Michael Januszyk MD

All Publications

• Editorial for Special Issue on Artificial Intelligence in Tissue Engineering and Biology. Tissue engineering. Part A Guo, J. L., Januszyk, M., Longaker, M. T. 2024

  Abstract

  N/A.

  View details for DOI 10.1089/ten.TEA.2024.0240

  View details for PubMedID 39162812

• HoloDIEP-Faster and More Accurate Intraoperative DIEA Perforator Mapping Using a Novel Mixed Reality Tool. Journal of reconstructive microsurgery Necker, F. N., Cholok, D. J., Fischer, M. J., Shaheen, M. S., Gifford, K., Januszyk, M., Leuze, C. W., Scholz, M., Daniel, B. L., Momeni, A. 2024

  Abstract

   Microsurgical breast reconstruction using abdominal tissue is a complex procedure, in part, due to variable vascular/perforator anatomy. Preoperative computed tomography angiography (CTA) has mitigated this challenge to some degree; yet it continues to pose certain challenges. The ability to map perforators with Mixed Reality has been demonstrated in case studies, but its accuracy has not been studied intraoperatively. Here, we compare the accuracy of "HoloDIEP" in identifying perforator location (vs. Doppler ultrasound) by using holographic 3D models derived from preoperative CTA. Using a custom application on HoloLens, the deep inferior epigastric artery vascular tree was traced in 15 patients who underwent microsurgical breast reconstruction. Perforator markings were compared against the 3D model in a coordinate system centered on the umbilicus. Holographic- and Doppler-identified markings were compared using a perspective-corrected photo technique against the 3D model along with measurement of duration of perforator mapping for each technique. Vascular points in HoloDIEP skin markings were -0.97 ± 6.2 mm (perforators: -0.62 ± 6.13 mm) away from 3D-model ground-truth in radial length from the umbilicus at a true distance of 10.81 ± 6.14 mm (perforators: 11.40 ± 6.15 mm). Absolute difference in radial distance was twice as high for Doppler markings compared with Holo-markings (9.71 ± 6.16 and 4.02 ± 3.20 mm, respectively). Only in half of all cases (7/14), more than 50% of the Doppler-identified points were reasonably close (<30 mm) to 3D-model ground-truth. HoloDIEP was twice as fast as Doppler ultrasound (76.9s vs. 150.4 s per abdomen). HoloDIEP allows for faster and more accurate intraoperative perforator mapping than Doppler ultrasound.

  View details for DOI 10.1055/s-0044-1788548

  View details for PubMedID 39038461

• Understanding the Foreign Body Response via Single-Cell Meta-Analysis. Biology Liang, N. E., Parker, J. B., Lu, J. M., Januszyk, M., Wan, D. C., Griffin, M., Longaker, M. T. 2024; 13 (7)

  Abstract

  Foreign body response (FBR) is a universal reaction to implanted biomaterial that can affect the function and longevity of the implant. A few studies have attempted to identify targets for treating FBR through the use of single-cell RNA sequencing (scRNA-seq), though the generalizability of these findings from an individual study may be limited. In our study, we perform a meta-analysis of scRNA-seq data from all available FBR mouse studies and integrate these data to identify gene signatures specific to FBR across different models and anatomic locations. We identify subclusters of fibroblasts and macrophages that emerge in response to foreign bodies and characterize their signaling pathways, gene ontology terms, and downstream mediators. The fibroblast subpopulations enriched in the setting of FBR demonstrated significant signaling interactions in the transforming growth factor-beta (TGF-beta) signaling pathway, with known pro-fibrotic mediators identified as top expressed genes in these FBR-derived fibroblasts. In contrast, FBR-enriched macrophage subclusters highly expressed pro-fibrotic and pro-inflammatory mediators downstream of tumor necrosis factor (TNF) signaling. Cell-cell interactions were additionally interrogated using CellChat, with identification of key signaling interactions enriched between fibroblasts and macrophages in FBR. By combining multiple FBR datasets, our meta-analysis study identifies common cell-specific gene signatures enriched in foreign body reactions, providing potential therapeutic targets for patients requiring medical implants across a myriad of devices and indications.

  View details for DOI 10.3390/biology13070540

  View details for PubMedID 39056733

• Circulating Mechanoresponsive Myeloid Cells Contribute To Fibrosis Across Disease States And Organ Systems Chen, K., Henn, D., Sivaraj, D., Fischer, K. S., Padmanabhan, J., Januszyk, M., Gurtner, G. C. WILEY. 2024: 525-526

  View details for Web of Science ID 001290635400059

• Single-cell transcriptional analysis of irradiated skin reveals changes in fibroblast subpopulations and variability in caveolin expression. Radiation oncology (London, England) Kameni, L. E., Griffin, M., Berry, C. E., Shariatzadeh, S., Downer, M. A., Valencia, C., Fazilat, A. Z., Nazerali, R., Momeni, A., Januszyk, M., Longaker, M. T., Wan, D. C. 2024; 19 (1): 82

  Abstract

  Radiation-induced fibrosis (RIF) is an important late complication of radiation therapy, and the resulting damaging effects of RIF can significantly impact reconstructive outcomes. There is currently a paucity of effective treatment options available, likely due to the continuing knowledge gap surrounding the cellular mechanisms involved. In this study, detailed analyses of irradiated and non-irradiated human skin samples were performed incorporating histological and single-cell transcriptional analysis to identify novel features guiding development of skin fibrosis following radiation injury.Paired irradiated and contralateral non-irradiated skin samples were obtained from six female patients undergoing post-oncologic breast reconstruction. Skin samples underwent histological evaluation, immunohistochemistry, and biomechanical testing. Single-cell RNA sequencing was performed using the 10X single cell platform. Cells were separated into clusters using Seurat in R. The SingleR classifier was applied to ascribe cell type identities to each cluster. Differentially expressed genes characteristic to each cluster were then determined using non-parametric testing.Comparing irradiated and non-irradiated skin, epidermal atrophy, dermal thickening, and evidence of thick, disorganized collagen deposition within the extracellular matrix of irradiated skin were readily appreciated on histology. These histologic features were associated with stiffness that was higher in irradiated skin. Single-cell RNA sequencing revealed six predominant cell types. Focusing on fibroblasts/stromal lineage cells, five distinct transcriptional clusters (Clusters 0-4) were identified. Interestingly, while all clusters were noted to express Cav1, Cluster 2 was the only one to also express Cav2. Immunohistochemistry demonstrated increased expression of Cav2 in irradiated skin, whereas Cav1 was more readily identified in non-irradiated skin, suggesting Cav1 and Cav2 may act antagonistically to modulate fibrotic cellular responses.In response to radiation therapy, specific changes to fibroblast subpopulations and enhanced Cav2 expression may contribute to fibrosis. Altogether, this study introduces a novel pathway of caveolin involvement which may contribute to fibrotic development following radiation injury.

  View details for DOI 10.1186/s13014-024-02472-z

  View details for PubMedID 38926892

  View details for PubMedCentralID 6329848

• Hematoxylin and Eosin Architecture Uncovers Clinically Divergent Niches in Pancreatic Cancer. Tissue engineering. Part A Guo, J. L., Lopez, D. M., Mascharak, S., Foster, D. S., Khan, A., Davitt, M. F., Nguyen, A. T., Burcham, A. R., Chinta, M. S., Guardino, N. J., Griffin, M., Miller, E., Januszyk, M., Raghavan, S. S., Longacre, T. A., Delitto, D. J., Norton, J. A., Longaker, M. T. 2024

  Abstract

  Pancreatic ductal adenocarcinoma (PDAC) represents one of the only cancers with an increasing incidence rate and is often associated with intra- and peri-tumoral scarring, referred to as desmoplasia. This scarring is highly heterogeneous in extracellular matrix (ECM) architecture and plays complex roles in both tumor biology and clinical outcomes that are not yet fully understood. Using hematoxylin and eosin (H&E), a routine histological stain utilized in existing clinical workflows, we quantified ECM architecture in 85 patient samples to assess relationships between desmoplastic architecture and clinical outcomes such as survival time and disease recurrence. By utilizing unsupervised machine learning (ML) to summarize a latent space across 147 local (e.g. fiber length, solidity) and global (e.g. fiber branching, porosity) H&E-based features, we identified a continuum of histological architectures that were associated with differences in both survival and recurrence. Further, we mapped H&E architectures to a CO-Detection by indEXing (CODEX) reference atlas, revealing localized cell- and protein-based niches associated with outcome-positive vs. outcome-negative scarring in the tumor microenvironment. Overall, our study utilizes standard H&E staining to uncover clinically relevant associations between desmoplastic organization and PDAC outcomes, offering a translatable pipeline to support prognostic decision-making and a blueprint of spatial-biological factors for modeling by tissue engineering methods.

  View details for DOI 10.1089/ten.TEA.2024.0039

  View details for PubMedID 38874979

• Healing of Chronically Irradiated Excisional Wounds Improved by Topical Deferoxamine Treatment Berry, C., Griffin, M., Kameni, L., Abbas, D., Downer, M., Parker, J. B., Liang, N., Januszyk, M., Longaker, M. T., Wan, D. C. LIPPINCOTT WILLIAMS & WILKINS. 2023: S382-S383

  View details for Web of Science ID 001094086301234

• Single-Cell RNA-Seq Analysis Reveals Similar Fibroblasts in Irradiated Skin of Humans, Mice, and Pigs Kameni, L., Berry, C., Griffin, M., Januszyk, M., Downer, M., Huber, J. L., Parker, J., Momeni, A., Longaker, M. T., Wan, D. C. LIPPINCOTT WILLIAMS & WILKINS. 2023: S389

  View details for Web of Science ID 001094086301247

• Fat Grafting Treatment for Radiation-Induced Fibrosis Results in Downregulation of Inflammatory and Fibrotic Signaling Pathways Berry, C., Abbas, D., Kameni, L., Griffin, M., Downer, M., Parker, J. B., Guo, J. L., Januszyk, M., Longaker, M. T., Wan, D. C. LIPPINCOTT WILLIAMS & WILKINS. 2023: S381-S382

  View details for Web of Science ID 001094086301232

• Meta-Analysis of Single-Cell Transcriptomics Data of Cardiac Fibroblasts Reveals Temporal Heterogeneity of Cardiac Fibroblast Response after MI Lu, J., Januszyk, M., Griffin, M., Guo, J. L., Wan, D. C., Longaker, M. T. LIPPINCOTT WILLIAMS & WILKINS. 2023: S68

  View details for Web of Science ID 001094086300124

• Ferropotosis Levels Decrease in Response to Deferoxamine Treatment in Irradiated Murine Skin Berry, C., Kameni, L., Griffin, M., Downer, M., Parker, J. B., Guo, J. L., Liang, N., Januszyk, M., Longaker, M. T., Wan, D. C. LIPPINCOTT WILLIAMS & WILKINS. 2023: S382

  View details for Web of Science ID 001094086301233

• A Review of Radiation-Induced Vascular Injury and Clinical Impact. Annals of plastic surgery Kameni, L. E., Januszyk, M., Berry, C. E., Downer, M. A., Parker, J. B., Morgan, A. G., Valencia, C., Griffin, M., Li, D. J., Liang, N. E., Momeni, A., Longaker, M. T., Wan, D. C. 2023

  Abstract

  ABSTRACT: The number of cancer survivors continues to increase because of advances in therapeutic modalities. Along with surgery and chemotherapy, radiotherapy is a commonly used treatment modality in roughly half of all cancer patients. It is particularly helpful in the oncologic treatment of patients with breast, head and neck, and prostate malignancies. Unfortunately, among patients receiving radiation therapy, long-term sequalae are often unavoidable, and there is accumulating clinical evidence suggesting significant radiation-related damage to the vascular endothelium. Ionizing radiation has been known to cause obliterative fibrosis and increased wall thickness in irradiated blood vessels. Clinically, these vascular changes induced by ionizing radiation can pose unique surgical challenges when operating in radiated fields. Here, we review the relevant literature on radiation-induced vascular damage focusing on mechanisms and signaling pathways involved and highlight microsurgical anastomotic outcomes after radiotherapy. In addition, we briefly comment on potential therapeutic strategies, which may have the ability to mitigate radiation injury to the vascular endothelium.

  View details for DOI 10.1097/SAP.0000000000003723

  View details for PubMedID 37962260

• Optimized Nuclei Isolation from Fresh and Frozen Solid Tumor Specimens for Multiome Sequencing. Journal of visualized experiments : JoVE Foster, D. S., Griffin, M., Januszyk, M., Delitto, D., Norton, J. A., Longaker, M. T. 2023

  Abstract

  Multiome sequencing, which provides same-cell/paired single-cell RNA- and the assay for transposase-accessible chromatin with sequencing (ATAC-sequencing) data, represents a breakthrough in our ability to discern tumor cell heterogeneity-a primary focus of translational cancer research at this time. However, the quality of sequencing data acquired using this advanced modality is highly dependent on the quality of the input material. Digestion conditions need to be optimized to maximize cell yield without sacrificing quality. This is particularly challenging in the context of solid tumors with dense desmoplastic matrices that must be gently broken down for cell release. Freshly isolated cells from solid tumor tissue are more fragile than those isolated from cell lines. Additionally, as the cell types isolated are heterogeneous, conditions should be selected to support the total cell population. Finally, nuclear isolation conditions must be optimized based on these qualities in terms of lysis times and reagent types/ratios. In this article, we describe our experience with nuclear isolation for the 10x Genomics multiome sequencing platform from solid tumor specimens. We provide recommendations for tissue digestion, storage of single-cell suspensions (if desired), and nuclear isolation and assessment.

  View details for DOI 10.3791/65831

  View details for PubMedID 37902368

• Desmoplastic stromal signatures predict patient outcomes in pancreatic ductal adenocarcinoma. Cell reports. Medicine Mascharak, S., Guo, J. L., Foster, D. S., Khan, A., Davitt, M. F., Nguyen, A. T., Burcham, A. R., Chinta, M. S., Guardino, N. J., Griffin, M., Lopez, D. M., Miller, E., Januszyk, M., Raghavan, S. S., Longacre, T. A., Delitto, D. J., Norton, J. A., Longaker, M. T. 2023: 101248

  Abstract

  Pancreatic ductal adenocarcinoma (PDAC) is projected to become the second leading cause of cancer-related death. Hallmarks include desmoplasia with variable extracellular matrix (ECM) architecture and a complex microenvironment with spatially defined tumor, stromal, and immune populations. Nevertheless, the role of desmoplastic spatial organization in patient/tumor variability remains underexplored, which we elucidate using two technologies. First, we quantify ECM patterning in 437 patients, revealing architectures associated with disease-free and overall survival. Second, we spatially profile the cellular milieu of 78 specimens using codetection by indexing, identifying an axis of pro-inflammatory cell interactions predictive of poorer outcomes. We discover that clinical characteristics, including neoadjuvant chemotherapy status, tumor stage, and ECM architecture, correlate with differential stromal-immune organization, including fibroblast subtypes with distinct niches. Lastly, we define unified signatures that predict survival with areas under the receiver operating characteristic curve (AUCs) of 0.872-0.903, differentiating survivorship by 655 days. Overall, our findings establish matrix ultrastructural and cellular organizations of fibrosis linked to poorer outcomes.

  View details for DOI 10.1016/j.xcrm.2023.101248

  View details for PubMedID 37865092

• Allometrically scaling tissue forces drive pathological foreign-body responses to implants via Rac2-activated myeloid cells. Nature biomedical engineering Padmanabhan, J., Chen, K., Sivaraj, D., Henn, D., Kuehlmann, B. A., Kussie, H. C., Zhao, E. T., Kahn, A., Bonham, C. A., Dohi, T., Beck, T. C., Trotsyuk, A. A., Stern-Buchbinder, Z. A., Than, P. A., Hosseini, H. S., Barrera, J. A., Magbual, N. J., Leeolou, M. C., Fischer, K. S., Tigchelaar, S. S., Lin, J. Q., Perrault, D. P., Borrelli, M. R., Kwon, S. H., Maan, Z. N., Dunn, J. C., Nazerali, R., Januszyk, M., Prantl, L., Gurtner, G. C. 2023

  Abstract

  Small animals do not replicate the severity of the human foreign-body response (FBR) to implants. Here we show that the FBR can be driven by forces generated at the implant surface that, owing to allometric scaling, increase exponentially with body size. We found that the human FBR is mediated by immune-cell-specific RAC2 mechanotransduction signalling, independently of the chemistry and mechanical properties of the implant, and that a pathological FBR that is human-like at the molecular, cellular and tissue levels can be induced in mice via the application of human-tissue-scale forces through a vibrating silicone implant. FBRs to such elevated extrinsic forces in the mice were also mediated by the activation of Rac2 signalling in a subpopulation of mechanoresponsive myeloid cells, which could be substantially reduced via the pharmacological or genetic inhibition of Rac2. Our findings provide an explanation for the stark differences in FBRs observed in small animals and humans, and have implications for the design and safety of implantable devices.

  View details for DOI 10.1038/s41551-023-01091-5

  View details for PubMedID 37749310

  View details for PubMedCentralID 2966551

• Cas9-mediated knockout of Ndrg2 enhances the regenerative potential of dendritic cells for wound healing. Nature communications Henn, D., Zhao, D., Sivaraj, D., Trotsyuk, A., Bonham, C. A., Fischer, K. S., Kehl, T., Fehlmann, T., Greco, A. H., Kussie, H. C., Moortgat Illouz, S. E., Padmanabhan, J., Barrera, J. A., Kneser, U., Lenhof, H., Januszyk, M., Levi, B., Keller, A., Longaker, M. T., Chen, K., Qi, L. S., Gurtner, G. C. 2023; 14 (1): 4729

  Abstract

  Chronic wounds impose a significant healthcare burden to a broad patient population. Cell-based therapies, while having shown benefits for the treatment of chronic wounds, have not yet achieved widespread adoption into clinical practice. We developed a CRISPR/Cas9 approach to precisely edit murine dendritic cells to enhance their therapeutic potential for healing chronic wounds. Using single-cell RNA sequencing of tolerogenic dendritic cells, we identified N-myc downregulated gene 2 (Ndrg2), which marks a specific population of dendritic cell progenitors, as a promising target for CRISPR knockout. Ndrg2-knockout alters the transcriptomic profile of dendritic cells and preserves an immature cell state with a strong pro-angiogenic and regenerative capacity. We then incorporated our CRISPR-based cell engineering within a therapeutic hydrogel for in vivo cell delivery and developed an effective translational approach for dendritic cell-based immunotherapy that accelerated healing of full-thickness wounds in both non-diabetic and diabetic mouse models. These findings could open the door to future clinical trials using safe gene editing in dendritic cells for treating various types of chronic wounds.

  View details for DOI 10.1038/s41467-023-40519-z

  View details for PubMedID 37550295

• Call for Special Issue Papers: Artificial Intelligence in Tissue Engineering and Biology. Tissue engineering. Part A Guo, J. L., Januszyk, M., Longaker, M. T. 2023

  View details for DOI 10.1089/ten.tea.2023.29049.cfp

  View details for PubMedID 37466469

• Call for Special Issue Papers: Artificial Intelligence in Tissue Engineering and Biology. Tissue engineering. Part B, Reviews Guo, J. L., Januszyk, M., Longaker, M. T. 2023

  View details for DOI 10.1089/ten.teb.2023.29019.cfp

  View details for PubMedID 37466464

• Call for Special Issue Papers: Artificial Intelligence in Tissue Engineering and Biology. Tissue engineering. Part C, Methods Guo, J. L., Januszyk, M., Longaker, M. T. 2023

  View details for DOI 10.1089/ten.tec.2023.29040.cfp

  View details for PubMedID 37466465

• Radiation Injury Genetically Alters Fibroblast Subpopulations to Induce Fibrosis Abbas, D., Griffin, M., Guo, J. L., Lavin, C. V., Fahy, E. J., Guardino, N. J., Lintel, H., Januszyk, M., Longaker, M. T., Wan, D. C. LIPPINCOTT WILLIAMS & WILKINS. 2023: S94

  View details for Web of Science ID 000989943300243

• Developing a Mouse Model to Evaluate Tibial Distraction Osteogenesis DiIorio, S., Tevlin, R., Shah, H. N., Salhotra, A., Griffin, M., Januszyk, M., Wan, D. C., Longaker, M. T. LIPPINCOTT WILLIAMS & WILKINS. 2023: S90

  View details for Web of Science ID 000989943300230

• Spatial Fidelity of Microvascular Perforating Vessels as Perceived by Augmented Reality Virtual Projections. Plastic and reconstructive surgery Cholok, D. J., Fischer, M. J., Leuze, C. W., Januszyk, M., Daniel, B. L., Momeni, A. 2023

  Abstract

  Autologous breast reconstruction yields improved long-term aesthetic results but requires increased resources of practitioners and hospital systems. Innovations in radiographic imaging have been used increasingly to improve the efficiency and success of free-flap harvest. Augmented reality (AR) affords the opportunity to superimpose relevant imaging on a surgeon's native field of view, potentially facilitating dissection of anatomically variable structures. To validate the spatial fidelity of AR projections of deep inferior epigastric perforator flap (DIEP) relevant anatomy, comparisons of 3D models and their virtual renderings were performed by four independent observers. Measured discrepancies between the real and holographic models were evaluated.3D-printed models of DIEP relevant anatomy were fabricated from CTA data from 19 de-identified patients. The corresponding CTA data was similarly formatted for the Microsoft Hololens to generate corresponding projections. Anatomic points were initially measured on 3D models, after which, the corresponding points were measured on the Hololens projections from two separate vantages. Statistical analyses, including Generalized Linear Modeling, were performed to characterize spatial fidelity regarding translation, rotation, and scale of holographic projections.Amongst all participants, the median translational displacement at corresponding points was 9.0 mm, 12.1 mm, and 13.5 mm between the real 3D model and V1, 3D model and V2, and between V1 and V2, respectively.Corresponding points, including topography of perforating vessels for the purposes of breast reconstruction can be identified within millimeters, but there remain multiple independent contributors of error, most notably the participant and location at which the projection is perceived.

  View details for DOI 10.1097/PRS.0000000000010592

  View details for PubMedID 37092985

• Nitric oxide-releasing gel accelerates healing in a diabetic murine splinted excisional wound model. Frontiers in medicine Sivaraj, D., Noishiki, C., Kosaric, N., Kiwanuka, H., Kussie, H. C., Henn, D., Fischer, K. S., Trotsyuk, A. A., Greco, A. H., Kuehlmann, B. A., Quintero, F., Leeolou, M. C., Granoski, M. B., Hostler, A. C., Hahn, W. W., Januszyk, M., Murad, F., Chen, K., Gurtner, G. C. 2023; 10: 1060758

  Abstract

  According to the American Diabetes Association (ADA), 9-12 million patients suffer from chronic ulceration each year, costing the healthcare system over USD $25 billion annually. There is a significant unmet need for new and efficacious therapies to accelerate closure of non-healing wounds. Nitric Oxide (NO) levels typically increase rapidly after skin injury in the inflammatory phase and gradually diminish as wound healing progresses. The effect of increased NO concentration on promoting re-epithelization and wound closure has yet to be described in the context of diabetic wound healing.In this study, we investigated the effects of local administration of an NO-releasing gel on excisional wound healing in diabetic mice. The excisional wounds of each mouse received either NO-releasing gel or a control phosphate-buffered saline (PBS)-releasing gel treatment twice daily until complete wound closure.Topical administration of NO-gel significantly accelerated the rate of wound healing as compared with PBS-gel-treated mice during the later stages of healing. The treatment also promoted a more regenerative ECM architecture resulting in shorter, less dense, and more randomly aligned collagen fibers within the healed scars, similar to that of unwounded skin. Wound healing promoting factors fibronectin, TGF-β1, CD31, and VEGF were significantly elevated in NO vs. PBS-gel-treated wounds.The results of this work may have important clinical implications for the management of patients with non-healing wounds.

  View details for DOI 10.3389/fmed.2023.1060758

  View details for PubMedID 36999070

  View details for PubMedCentralID PMC10045479

• Mechanoresponsive Pancreatic Ductal Adenocarcinoma Cancer Associated Fibroblasts Shows an FAK-Dependent Subtype Divergent from Canonical Fibrotic TGFB-Pathway Dependence Foster, D., Delitto, D., Januszyk, M., Yost, K., Griffin, M., Guo, J., Guardino, N., Delitto, A., Chinta, M., Burcham, A., Nguyen, A., Bauer-, K., Berry, C., Kim, A., Nosrati, F., Wapnir, I., Chang, H., Norton, J. A., Longaker, M. SPRINGER. 2023: S30-S31

  View details for Web of Science ID 001046841200059

• Denervation during mandibular distraction osteogenesis results in impaired bone formation. Scientific reports Tevlin, R., Griffin, M., Chen, K., Januszyk, M., Guardino, N., Spielman, A., Walters, S., Gold, G. E., Chan, C. K., Gurtner, G. C., Wan, D. C., Longaker, M. T. 2023; 13 (1): 2097

  Abstract

  Mandibular distraction osteogenesis (DO) is mediated by skeletal stem cells (SSCs) in mice, which enact bone regeneration via neural crest re-activation. As peripheral nerves are essential to progenitor function during development and in response to injury, we questioned if denervation impairs mandibular DO. C57Bl6 mice were divided into two groups: DO with a segmental defect in the inferior alveolar nerve (IAN) at the time of mandibular osteotomy ("DO Den") and DO with IAN intact ("DO Inn"). DO Den demonstrated significantly reduced histological and radiological osteogenesis relative to DO Inn. Denervation preceding DO results in reduced SSC amplification and osteogenic potential in mice. Single cell RNA sequencing analysis revealed that there was a predominance of innervated SSCs in clusters dominated by pathways related to bone formation. A rare human patient specimen was also analyzed and suggested that histological, radiological, and transcriptional alterations seen in mouse DO may be conserved in the setting of denervated human mandible distraction. Fibromodulin (FMOD) transcriptional and protein expression were reduced in denervated relative to innervated mouse and human mandible regenerate. Finally, when exogenous FMOD was added to DO-Den and DO-Inn SSCs undergoing in vitro osteogenic differentiation, the osteogenic potential of DO-Den SSCs was increased in comparison to control untreated DO-Den SSCs, modeling the superior osteogenic potential of DO-Inn SSCs.

  View details for DOI 10.1038/s41598-023-27921-9

  View details for PubMedID 36747028

• An Inexpensive 3D Printed Mouse Model of Successful, Complication-free Long Bone Distraction Osteogenesis. Plastic and reconstructive surgery. Global open Tevlin, R., Shah, H. N., Salhotra, A., Di Iorio, S. E., Griffin, M., Januszyk, M., Wan, D. C., Longaker, M. T. 2023; 11 (2): e4674

  Abstract

  Distraction osteogenesis (DO) is used for skeletal defects; however, up to 50% of cases exhibit complications. Previous mouse models of long bone DO have been anecdotally hampered by postoperative complications, expense, and availability. To improve clinical techniques, cost-effective, reliable animal models are needed. Our focus was to develop a new mouse tibial distractor, hypothesized to result in successful, complication-free DO.A lightweight tibial distractor was developed using CAD and 3D printing. The device was fixed to the tibia of C57Bl/6J mice prior to osteotomy. Postoperatively, mice underwent 5 days latency, 10 days distraction (0.15 mm every 12 hours), and 28 days consolidation. Bone regeneration was examined on postoperative day 43 using micro-computed tomography (μCT) and Movat's modified pentachrome staining on histology (mineralized volume fraction and pixels, respectively). Costs were recorded. We compared cohorts of 11 mice undergoing sham, DO, or acute lengthening (distractor acutely lengthened 3.0 mm).The histological bone regenerate was significantly increased in DO (1,879,257 ± 155,415 pixels) compared to acute lengthening (32847 ± 1589 pixels) (P < 0.0001). The mineralized volume fraction (bone/total tissue volume) of the regenerate was significantly increased in DO (0.9 ± 0.1) compared to acute lengthening (0.7 ± 0.1) (P < 0.001). There was no significant difference in bone regenerate between DO and sham. The distractor was relatively low cost ($11), with no complications.Histology and µCT analysis confirmed that the proposed tibial DO model resulted in successful bone formation. Our model is cost-effective and reproducible, enabling implementation in genetically dissectible transgenic mice.

  View details for DOI 10.1097/GOX.0000000000004674

  View details for PubMedID 36798717

  View details for PubMedCentralID PMC9925097

• Multiplexed evaluation of mouse wound tissue using oligonucleotide barcoding with single-cell RNA sequencing. STAR protocols Januszyk, M., Griffin, M., Mascharak, S., Talbott, H. E., Chen, K., Henn, D., Spielman, A. F., Parker, J. B., Liang, N. E., Cotterell, A., Guardino, N., Foster, D. S., Wagh, D., Coller, J., Gurtner, G. C., Wan, D. C., Longaker, M. T. 2022; 4 (1): 101946

  Abstract

  Despite its rapidly increased availability for the study of complex tissue, single-cell RNA sequencing remains prohibitively expensive for large studies. Here, we present a protocol using oligonucleotide barcoding for the tagging and pooling of multiple samples from healing wounds, which are among the most challenging tissue types for this application. We describe steps to generate skin wounds in mice, followed by tissue harvest and oligonucleotide barcoding. This protocol is also applicable to other species including rats, pigs, and humans. For complete details on the use and execution of this protocol, please refer to Stoeckius etal. (2018),1 Galiano etal. (2004),2 and Mascharak etal. (2022).3.

  View details for DOI 10.1016/j.xpro.2022.101946

  View details for PubMedID 36525348

• Macrophage inflammatory and regenerative response periodicity is programmed by cell cycle and chromatin state. Molecular cell Daniel, B., Belk, J. A., Meier, S. L., Chen, A. Y., Sandor, K., Czimmerer, Z., Varga, Z., Bene, K., Buquicchio, F. A., Qi, Y., Kitano, H., Wheeler, J. R., Foster, D. S., Januszyk, M., Longaker, M. T., Chang, H. Y., Satpathy, A. T. 2022

  Abstract

  Cell cycle (CC) facilitates cell division via robust, cyclical gene expression. Protective immunity requires the expansion of pathogen-responsive cell types, but whether CC confers unique gene expression programs that direct the subsequent immunological response remains unclear. Here, we demonstrate that single macrophages (MFs) adopt different plasticity states in CC, which leads to heterogeneous cytokine-induced polarization, priming, and repolarization programs. Specifically, MF plasticity to interferon gamma (IFNG) is substantially reduced during S-G2/M, whereas interleukin 4 (IL-4) induces S-G2/M-biased gene expression, mediated by CC-biased enhancers. Additionally, IL-4 polarization shifts the CC-phase distribution of MFs toward the G2/M phase, providing a subpopulation-specific mechanism for IL-4-induced, dampened IFNG responsiveness. Finally, we demonstrate CC-dependent MF responses in murine and human disease settings invivo, including Th2-driven airway inflammation and pulmonary fibrosis, where MFs express an S-G2/M-biased tissue remodeling gene program. Therefore, MF inflammatory and regenerative responses are gated by CC in a cyclical, phase-dependent manner.

  View details for DOI 10.1016/j.molcel.2022.11.017

  View details for PubMedID 36521490

• Wireless, closed-loop, smart bandage with integrated sensors and stimulators for advanced wound care and accelerated healing. Nature biotechnology Jiang, Y., Trotsyuk, A. A., Niu, S., Henn, D., Chen, K., Shih, C. C., Larson, M. R., Mermin-Bunnell, A. M., Mittal, S., Lai, J. C., Saberi, A., Beard, E., Jing, S., Zhong, D., Steele, S. R., Sun, K., Jain, T., Zhao, E., Neimeth, C. R., Viana, W. G., Tang, J., Sivaraj, D., Padmanabhan, J., Rodrigues, M., Perrault, D. P., Chattopadhyay, A., Maan, Z. N., Leeolou, M. C., Bonham, C. A., Kwon, S. H., Kussie, H. C., Fischer, K. S., Gurusankar, G., Liang, K., Zhang, K., Nag, R., Snyder, M. P., Januszyk, M., Gurtner, G. C., Bao, Z. 2022

  Abstract

  'Smart' bandages based on multimodal wearable devices could enable real-time physiological monitoring and active intervention to promote healing of chronic wounds. However, there has been limited development in incorporation of both sensors and stimulators for the current smart bandage technologies. Additionally, while adhesive electrodes are essential for robust signal transduction, detachment of existing adhesive dressings can lead to secondary damage to delicate wound tissues without switchable adhesion. Here we overcome these issues by developing a flexible bioelectronic system consisting of wirelessly powered, closed-loop sensing and stimulation circuits with skin-interfacing hydrogel electrodes capable of on-demand adhesion and detachment. In mice, we demonstrate that our wound care system can continuously monitor skin impedance and temperature and deliver electrical stimulation in response to the wound environment. Across preclinical wound models, the treatment group healed ~25% more rapidly and with ~50% enhancement in dermal remodeling compared with control. Further, we observed activation of proregenerative genes in monocyte and macrophage cell populations, which may enhance tissue regeneration, neovascularization and dermal recovery.

  View details for DOI 10.1038/s41587-022-01528-3

  View details for PubMedID 36424488

  View details for PubMedCentralID 5350204

• Engrailed-Positive Fibroblasts: The Primary Cell Type Present in Fibrotic Capsules During Foreign Body Response Parker, J. B., Griffin, M., Mascharak, S., Spielman, A., Cotterell, A. C., Abbas, D., Lintel, H., Januszyk, M., Wan, D. C., Longaker, M. T. LIPPINCOTT WILLIAMS & WILKINS. 2022: S68

  View details for Web of Science ID 000867877000171

• Inhibition of Yes-Associated Protein Promotes Skin Wound Regeneration in Large Animals Januszyk, M., Talbott, H. E., Griffin, M., Guardino, N., Spielman, A., Guo, J. L., Mascharak, S., Wan, D. C., Longaker, M. T. LIPPINCOTT WILLIAMS & WILKINS. 2022: S196

  View details for DOI 10.1097/01.XCS.0000894508.92389.a2

  View details for Web of Science ID 000867889300379

• Denervation During Mouse and Human Mandibular Distraction Osteogenesis Results in Impaired Osteogenesis Tevlin, R., Griffin, M., Chen, K., Januszyk, M., Wan, D. C., Longaker, M. T. LIPPINCOTT WILLIAMS & WILKINS. 2022: S202

  View details for DOI 10.1097/01.XCS.0000894560.64479.80

  View details for Web of Science ID 000867889300393

• Multiomic analysis reveals conservation of cancer-associated fibroblast phenotypes across species and tissue of origin. Cancer cell Foster, D. S., Januszyk, M., Delitto, D., Yost, K. E., Griffin, M., Guo, J., Guardino, N., Delitto, A. E., Chinta, M., Burcham, A. R., Nguyen, A. T., Bauer-Rowe, K. E., Titan, A. L., Salhotra, A., Jones, R. E., da Silva, O., Lindsay, H. G., Berry, C. E., Chen, K., Henn, D., Mascharak, S., Talbott, H. E., Kim, A., Nosrati, F., Sivaraj, D., Ransom, R. C., Matthews, M., Khan, A., Wagh, D., Coller, J., Gurtner, G. C., Wan, D. C., Wapnir, I. L., Chang, H. Y., Norton, J. A., Longaker, M. T. 2022

  Abstract

  Cancer-associated fibroblasts (CAFs) are integral to the solid tumor microenvironment. CAFs were once thought to be a relatively uniform population of matrix-producing cells, but single-cell RNA sequencing has revealed diverse CAF phenotypes. Here, we further probed CAF heterogeneity with a comprehensive multiomics approach. Using paired, same-cell chromatin accessibility and transcriptome analysis, we provided an integrated analysis of CAF subpopulations over a complex spatial transcriptomic and proteomic landscape to identify three superclusters: steady state-like (SSL), mechanoresponsive (MR), and immunomodulatory (IM) CAFs. These superclusters are recapitulated across multiple tissue types and species. Selective disruption of underlying mechanical force or immune checkpoint inhibition therapy results in shifts in CAF subpopulation distributions and affected tumor growth. As such, the balance among CAF superclusters may have considerable translational implications. Collectively, this research expands our understanding of CAF biology, identifying regulatory pathways in CAF differentiation and elucidating therapeutic targets in a species- and tumor-agnostic manner.

  View details for DOI 10.1016/j.ccell.2022.09.015

  View details for PubMedID 36270275

• The Majority of Venous Thromboembolism Events Should Occur in Lower Risk Aesthetic Surgery Patients: A Simulation Study. Plastic and reconstructive surgery. Global open Pannucci, C. J., Momeni, A., Januszyk, M. 2022; 10 (10): e4573

  Abstract

  Evidence-based venous thromboembolism (VTE) prevention among aesthetic patients is lacking. This study seeks to (1) quantify 2005 Caprini scores in primary breast augmentation patients, (2) determine the proportion of patients with potentially modifiable VTE risk factors, and (3) project, using Monte Carlo simulation, the expected distribution of Caprini scores among aesthetic surgery patients who develop VTE.Methods: The observational study (part 1) screened consecutive primary breast augmentation patients for VTE risk using the 2005 Caprini score. Aggregate scores were compiled, and the proportion of patients with potentially modifiable risk factors were identified. Part 2 used Monte Carlo simulation to generate risk score distributions for VTE events predicted to occur among randomly sampled patient cohorts with baseline Caprini risk profiles derived from the part 1 data.Results: One hundred patients had mean age of 35.7 years and mean body mass index of 23.8kg/m2. Median 2005 Caprini score was 3 (range, 2-8), with the majority (96%) having scores of ≤6. Twenty-eight percent of patients had at least one potentially modifiable risk factor or risk factor potentially benefiting from further investigation. Monte Carlo simulations demonstrated that for a population with 96% Caprini ≤6 (and 4% Caprini ≥7), 80% of VTE events would be expected to occur in patients with Caprini scores ≤6.Conclusions: The majority of breast augmentation patients in this study (96%) have 2005 Caprini scores ≤6. Twenty-eight percent of patients have potentially modifiable risk factors. The majority of patients with VTE after aesthetic surgery are expected to have lower Caprini risk scores.

  View details for DOI 10.1097/GOX.0000000000004573

  View details for PubMedID 36246074

• Machine Learning in Tissue Engineering. Tissue engineering. Part A Guo, J. L., Januszyk, M., Longaker, M. T. 2022

  Abstract

  Machine learning (ML) and artificial intelligence have accelerated scientific discovery, augmented clinical practice, and deepened fundamental understanding of many biological phenomena. ML technologies have now been applied to diverse areas of tissue engineering research, including biomaterial design, scaffold fabrication, and cell/tissue modeling. Emerging ML-empowered strategies include machine-optimized polymer synthesis, predictive modeling of scaffold fabrication processes, complex analyses of structure-function relationships, and deep learning of spatialized cell phenotypes and tissue composition. The emergence of ML in tissue engineering, while relatively recent, has already enabled increasingly complex and multivariate analyses of the relationships between biological, chemical, and physical factors in driving tissue regenerative outcomes. This review highlights the novel methodologies, emerging strategies, and areas of potential growth within this rapidly evolving area of research.

  View details for DOI 10.1089/ten.TEA.2022.0128

  View details for PubMedID 35943870

• Partial Tendon Injury at the Tendon-to-Bone Enthesis Activates Skeletal Stem Cells. Stem cells translational medicine Titan, A. L., Davitt, M., Foster, D., Salhotra, A., Menon, S., Chen, K., Fahy, E., Lopez, M., Jones, R. E., Baiu, I., Burcham, A., Januszyk, M., Gurtner, G., Fox, P., Chan, C., Quarto, N., Longaker, M. 2022

  Abstract

  The tendon enthesis plays a critical role in facilitating movement and reducing stress within joints. Partial enthesis injuries heal in a mechanically inferior manner and never achieve healthy tissue function. The cells responsible for tendon-to-bone healing remain incompletely characterized and their origin is unknown. Here, we evaluated the putative role of mouse skeletal stem cells (mSSCs) in the enthesis after partial-injury. We found that mSSCs were present at elevated levels within the enthesis following injury and that these cells downregulated TGFβ signaling pathway elements at both the RNA and protein levels. Exogenous application of TGFβ post-injury led to a reduced mSSC response and impaired healing, whereas treatment with a TGFβ inhibitor (SB43154) resulted in a more robust mSSC response. Collectively, these data suggest that mSSCs may augment tendon-to-bone healing by dampening the effects of TGFβ signaling within the mSSC niche.

  View details for DOI 10.1093/stcltm/szac027

  View details for PubMedID 35640155

• Disrupting mechanotransduction decreases fibrosis and contracture in split-thickness skin grafting. Science translational medicine Chen, K., Henn, D., Januszyk, M., Barrera, J. A., Noishiki, C., Bonham, C. A., Griffin, M., Tevlin, R., Carlomagno, T., Shannon, T., Fehlmann, T., Trotsyuk, A. A., Padmanabhan, J., Sivaraj, D., Perrault, D. P., Zamaleeva, A. I., Mays, C. J., Greco, A. H., Kwon, S. H., Leeolou, M. C., Huskins, S. L., Steele, S. R., Fischer, K. S., Kussie, H. C., Mittal, S., Mermin-Bunnell, A. M., Diaz Deleon, N. M., Lavin, C., Keller, A., Longaker, M. T., Gurtner, G. C. 2022; 14 (645): eabj9152

  Abstract

  Burns and other traumatic injuries represent a substantial biomedical burden. The current standard of care for deep injuries is autologous split-thickness skin grafting (STSG), which frequently results in contractures, abnormal pigmentation, and loss of biomechanical function. Currently, there are no effective therapies that can prevent fibrosis and contracture after STSG. Here, we have developed a clinically relevant porcine model of STSG and comprehensively characterized porcine cell populations involved in healing with single-cell resolution. We identified an up-regulation of proinflammatory and mechanotransduction signaling pathways in standard STSGs. Blocking mechanotransduction with a small-molecule focal adhesion kinase (FAK) inhibitor promoted healing, reduced contracture, mitigated scar formation, restored collagen architecture, and ultimately improved graft biomechanical properties. Acute mechanotransduction blockade up-regulated myeloid CXCL10-mediated anti-inflammation with decreased CXCL14-mediated myeloid and fibroblast recruitment. At later time points, mechanical signaling shifted fibroblasts toward profibrotic differentiation fates, and disruption of mechanotransduction modulated mesenchymal fibroblast differentiation states to block those responses, instead driving fibroblasts toward proregenerative, adipogenic states similar to unwounded skin. We then confirmed these two diverging fibroblast transcriptional trajectories in human skin, human scar, and a three-dimensional organotypic model of human skin. Together, pharmacological blockade of mechanotransduction markedly improved large animal healing after STSG by promoting both early, anti-inflammatory and late, regenerative transcriptional programs, resulting in healed tissue similar to unwounded skin. FAK inhibition could therefore supplement the current standard of care for traumatic and burn injuries.

  View details for DOI 10.1126/scitranslmed.abj9152

  View details for PubMedID 35584231

• Tension offloading improves cutaneous scar formation in Achilles tendon repair. Journal of surgical case reports Abbas, D. B., Lintel, H., Griffin, M., Guardino, N. J., Guo, J. L., Spielman, A. F., Cotterell, A. C., Parker, J. B., Januszyk, M., Wan, D. C. 2022; 2022 (3): rjac066

  Abstract

  Hypertrophic scar formation and non-healing wounds following Achilles tendon repair arise from poor vascularity to the incisional site or from excess mechanical stress/strain to the incision during the healing process. The embrace scar therapy dressing is a tension offloading device for incisional scars. This study explored the effects of tension offloading during Achilles scar formation. A healthy 30-year-old male without any medical co-morbidities developed an acute rupture of his left Achilles tendon. The patient underwent open repair 1 week after injury. At post-operative day (POD) 14, the patient started daily tension offloading treatment on the inferior portion of the incision through POD 120. By POD 120, the untreated portion of the Achilles incision appeared hypertrophic and hyperpigmented, while the treated portion of the scar appeared flat with minimal pigmentation changes. The 12-week treatment of tension offloading on an Achilles tendon repair incision significantly improved cosmesis compared to untreated incision.

  View details for DOI 10.1093/jscr/rjac066

  View details for PubMedID 35280050

• The Oral Mucosa Hosts Distinct Fibroblast Subpopulations to Facilitate Regenerative Wound Repair Griffin, M., Cook, J., Bofelli, D., Guardino, N., Spielman, A. F., Januszyk, M., Chen, K., Abbas, D. B., Zwick, R., Klein, O., Longaker, M. T. WILEY. 2022: A12-A13

  View details for Web of Science ID 000763583000035

• Galvanotactic Smart Bandage for Chronic Wound Management and Tissue Regeneration Trotsyuk, A. A., Jiang, Y., Niu, S., Henn, D., Chen, K., Larson, M., Beard, E., Saberi, A., Sivaraj, D., Mermin-Bunnell, A., Mittal, S., Jing, S., Kwon, S., Bonham, C., Padmanabhan, J., Perrault, D., Leeolou, M. C., Januszyk, M., Bao, Z., Gurtner, G. C. WILEY. 2022: A36

  View details for Web of Science ID 000763583000080

• Allometric Tissue-Scale Forces Activate Mechanoresponsive Immune Cells To Drive Pathological Foreign Body Response To Biomedical Implants Padmanabhan, J., Chen, K., Sivaraj, D., Kuehlmann, B., Bonham, C., Dohi, T., Henn, D., Stern-Buchbinder, Z., Than, P., Hosseini, H., Barrera, J., Kussie, H., Magbual, N., Borrelli, M., Trotsyuk, A. A., Kwon, S., Dunn, J., Maan, Z., Januszyk, M., Prantl, L., Gurtner, G. C. WILEY. 2022: A19-A20

  View details for Web of Science ID 000763583000048

• Multi-omic analysis reveals divergent molecular events in scarring and regenerative wound healing. Cell stem cell Mascharak, S., Talbott, H. E., Januszyk, M., Griffin, M., Chen, K., Davitt, M. F., Demeter, J., Henn, D., Bonham, C. A., Foster, D. S., Mooney, N., Cheng, R., Jackson, P. K., Wan, D. C., Gurtner, G. C., Longaker, M. T. 1800

  Abstract

  Regeneration is the holy grail of tissue repair, but skin injury typically yields fibrotic, non-functional scars. Developing pro-regenerative therapies requires rigorous understanding of the molecular progression from injury to fibrosis or regeneration. Here, we report the divergent molecular events driving skin wound cells toward scarring or regenerative fates. We profile scarring versus YAP-inhibition-induced wound regeneration at the transcriptional (single-cell RNA sequencing), protein (timsTOF proteomics), and tissue (extracellular matrix ultrastructural analysis) levels. Using cell-surface barcoding, we integrate these data to reveal fibrotic and regenerative "molecular trajectories" of healing. We show that disrupting YAP mechanotransduction yields regenerative repair by fibroblasts with activated Trps1 and Wnt signaling. Finally, via invivo gene knockdown and overexpression in wounds, we identify Trps1 as a key regulatory gene that is necessary and partially sufficient for wound regeneration. Our findings serve as a multi-omic map of wound regeneration and could have therapeutic implications for pathologic fibroses.

  View details for DOI 10.1016/j.stem.2021.12.011

  View details for PubMedID 35077667

• IQGAP1-mediated mechanical signaling promotes the foreign body response to biomedical implants. FASEB journal : official publication of the Federation of American Societies for Experimental Biology Sivaraj, D., Padmanabhan, J., Chen, K., Henn, D., Noishiki, C., Trotsyuk, A. A., Kussie, H. C., Leeolou, M. C., Magbual, N. J., Andrikopoulos, S., Perrault, D. P., Barrera, J. A., Januszyk, M., Gurtner, G. C. 2022; 36 (2): e22007

  Abstract

  The aim of this study was to further elucidate the molecular mechanisms that mediate pathologic foreign body response (FBR) to biomedical implants. The longevity of biomedical implants is limited by the FBR, which leads to implant failure and patient morbidity. Since the specific molecular mechanisms underlying fibrotic responses to biomedical implants have yet to be fully described, there are currently no targeted approaches to reduce pathologic FBR. We utilized proteomics analysis of human FBR samples to identify potential molecular targets for therapeutic inhibition of FBR. We then employed a murine model of FBR to further evaluate the role of this potential target. We performed histological and immunohistochemical analysis on the murine FBR capsule tissue, as well as single-cell RNA sequencing (scRNA-seq) on cells isolated from the capsules. We identified IQ motif containing GTPase activating protein 1 (IQGAP1) as the most promising of several targets, serving as a central molecular mediator in human and murine FBR compared to control subcutaneous tissue. IQGAP1-deficient mice displayed a significantly reduced FBR compared to wild-type mice as evidenced by lower levels of collagen deposition and maturity. Our scRNA-seq analysis revealed that decreasing IQGAP1 resulted in diminished transcription of mechanotransduction, inflammation, and fibrosis-related genes, which was confirmed on the protein level with immunofluorescent staining. The deficiency of IQGAP1 significantly attenuates FBR by deactivating downstream mechanotransduction signaling, inflammation, and fibrotic pathways. IQGAP1 may be a promising target for rational therapeutic design to mitigate pathologic FBR around biomedical implants.

  View details for DOI 10.1096/fj.202101354

  View details for PubMedID 35051300

• Cancer-Associated Fibroblasts Share Highly Conserved Phenotypes and Functions Across Tumor Types and Species Foster, D. S., Januszyk, M., Yost, K. E., Chinta, M., Titan, A. L., Wapnir, I. L., Gurtner, G. C., Chang, H. Y., Norton, J. A., Longaker, M. T. ELSEVIER SCIENCE INC. 2021: S243-S244

  View details for Web of Science ID 000718303100463

• Acellular Dermal Matrix Modulation of the Peri-Prosthetic Breast Microenvironment During Breast Reconstruction Tevlin, R., Januszyk, M., Griffin, M., Shefren, K., Chan, C. F., Momeni, A., Wan, D. C., Longaker, M. T. ELSEVIER SCIENCE INC. 2021: S195-S196

  View details for Web of Science ID 000718303100367

• Fibroblast Sub-Populations Dynamically Change Composition to Heal Dorsal Skin Radiation Wounds in Wild-Type Mice Abbas, D. B., Griffin, M., Fahy, E. J., Lavin, C., Lee, D., Mascharak, S., King, M., Januszyk, M., Longaker, M. T., Wan, D. C. ELSEVIER SCIENCE INC. 2021: S207-S208

  View details for Web of Science ID 000718303100389

• Denervation During Mandibular Distraction Osteogenesis Results in Impaired Osteogenesis Tevlin, R., Januszyk, M., Griffin, M., Salhotra, A., Wan, D. C., Chan, C. F., Longaker, M. T. ELSEVIER SCIENCE INC. 2021: S196-S197

  View details for Web of Science ID 000718303100369

• Integrated spatial multiomics reveals fibroblast fate during tissue repair. Proceedings of the National Academy of Sciences of the United States of America Foster, D. S., Januszyk, M., Yost, K. E., Chinta, M. S., Gulati, G. S., Nguyen, A. T., Burcham, A. R., Salhotra, A., Ransom, R. C., Henn, D., Chen, K., Mascharak, S., Tolentino, K., Titan, A. L., Jones, R. E., da Silva, O., Leavitt, W. T., Marshall, C. D., des Jardins-Park, H. E., Hu, M. S., Wan, D. C., Wernig, G., Wagh, D., Coller, J., Norton, J. A., Gurtner, G. C., Newman, A. M., Chang, H. Y., Longaker, M. T. 2021; 118 (41)

  Abstract

  In the skin, tissue injury results in fibrosis in the form of scars composed of dense extracellular matrix deposited by fibroblasts. The therapeutic goal of regenerative wound healing has remained elusive, in part because principles of fibroblast programming and adaptive response to injury remain incompletely understood. Here, we present a multimodal -omics platform for the comprehensive study of cell populations in complex tissue, which has allowed us to characterize the cells involved in wound healing across both time and space. We employ a stented wound model that recapitulates human tissue repair kinetics and multiple Rainbow transgenic lines to precisely track fibroblast fate during the physiologic response to skin injury. Through integrated analysis of single cell chromatin landscapes and gene expression states, coupled with spatial transcriptomic profiling, we are able to impute fibroblast epigenomes with temporospatial resolution. This has allowed us to reveal potential mechanisms controlling fibroblast fate during migration, proliferation, and differentiation following skin injury, and thereby reexamine the canonical phases of wound healing. These findings have broad implications for the study of tissue repair in complex organ systems.

  View details for DOI 10.1073/pnas.2110025118

  View details for PubMedID 34620713

• Inhibiting Fibroblast Mechanotransduction Modulates Severity of Idiopathic Pulmonary Fibrosis. Advances in wound care Trotsyuk, A. A., Chen, K., Kwon, S. H., Ma, K. C., Henn, D., Mermin-Bunnell, A. M., Mittal, S., Padmanabhan, J., Larson, M. R., Steele, S. R., Sivaraj, D., Bonham, C. A., Noishiki, C., Rodrigues, M., Jiang, Y., Jing, S., Niu, S., Chattopadhyay, A., Perrault, D. P., Leeolou, M. C., Fischer, K., Gurusankar, G., Choi Kussie, H., Wan, D. C., Januszyk, M., Longaker, M. T., Gurtner, G. C. 2021

  Abstract

  OBJECTIVE: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease that affects 63 in every 100,000 Americans. Its etiology remains unknown, although inflammatory pathways appear to be important. Given the dynamic environment of the lung, we examined the significance of mechanotransduction on both inflammatory and fibrotic signaling during IPF.INNOVATION: Mechanotransduction pathways have not been thoroughly examined in the context of lung disease and pharmacologic approaches for IPF do not currently target these pathways. The interplay between mechanical strain and inflammation in pulmonary fibrosis remain incompletely understood.APPROACH: In this study, we used conditional KO mice to block mechanotransduction by knocking out FAK (Focal Adhesion Kinase) expression in fibroblasts, followed by induction of pulmonary fibrosis using bleomycin. We examined both normal human and human IPF fibroblasts and used immunohistochemistry, qRT-PCR, and Western Blot to evaluate the effects of FAK inhibition (FAKI) on modulating fibrotic and inflammatory genes.RESULTS: Our data indicate that deletion of FAK in mice reduces expression of fibrotic and inflammatory genes in lungs. Similarly, mechanical straining in normal human lung fibroblasts activates inflammatory and fibrotic pathways. FAK inhibition decreases these signals but has less effect on IPF fibroblasts as compared to normal human fibroblasts.CONCLUSION: Administering FAKI at early stages of fibrosis may attenuate the FAK-mediated fibrotic response pathway in IPF, potentially mediating disease progression.

  View details for DOI 10.1089/wound.2021.0077

  View details for PubMedID 34544267

• JUN promotes hypertrophic skin scarring via CD36 in preclinical in vitro and in vivo models. Science translational medicine Griffin, M. F., Borrelli, M. R., Garcia, J. T., Januszyk, M., King, M., Lerbs, T., Cui, L., Moore, A. L., Shen, A. H., Mascharak, S., Diaz Deleon, N. M., Adem, S., Taylor, W. L., desJardins-Park, H. E., Gastou, M., Patel, R. A., Duoto, B. A., Sokol, J., Wei, Y., Foster, D., Chen, K., Wan, D. C., Gurtner, G. C., Lorenz, H. P., Chang, H. Y., Wernig, G., Longaker, M. T. 2021; 13 (609): eabb3312

  Abstract

  [Figure: see text].

  View details for DOI 10.1126/scitranslmed.abb3312

  View details for PubMedID 34516825

• Skeletal stem and progenitor cells maintain cranial suture patency and prevent craniosynostosis. Nature communications Menon, S., Salhotra, A., Shailendra, S., Tevlin, R., Ransom, R. C., Januszyk, M., Chan, C. K., Behr, B., Wan, D. C., Longaker, M. T., Quarto, N. 2021; 12 (1): 4640

  Abstract

  Cranial sutures are major growth centers for the calvarial vault, and their premature fusion leads to a pathologic condition called craniosynostosis. This study investigates whether skeletal stem/progenitor cells are resident in the cranial sutures. Prospective isolation by FACS identifies this population with a significant difference in spatio-temporal representation between fusing versus patent sutures. Transcriptomic analysis highlights a distinct signature in cellsderived from the physiological closing PF suture, and scRNA sequencing identifies transcriptional heterogeneity among sutures. Wnt-signaling activation increases skeletal stem/progenitor cells in sutures, whereas its inhibition decreases. Crossing Axin2LacZ/+ mouse, endowing enhanced Wnt activation, to a Twist1+/- mouse model of coronal craniosynostosis enriches skeletal stem/progenitor cells in sutures restoring patency. Co-transplantation of these cells with Wnt3a prevents resynostosis following suturectomy in Twist1+/- mice. Our study reveals that decrease and/or imbalance of skeletal stem/progenitor cells representation within sutures may underlie craniosynostosis. These findings have translational implications toward therapeutic approaches for craniosynostosis.

  View details for DOI 10.1038/s41467-021-24801-6

  View details for PubMedID 34330896

• Mechanical Strain Drives Myeloid Cell Differentiation Toward Pro-Inflammatory Subpopulations. Advances in wound care Chen, K., Henn, D., Sivaraj, D., Bonham, C. A., Griffin, M., Choi Kussie, H., Padmanabhan, J., Trotsyuk, A. A., Wan, D. C., Januszyk, M., Longaker, M. T., Gurtner, G. C. 2021

  Abstract

  OBJECTIVE: After injury, humans and other mammals heal by forming fibrotic scar tissue with diminished function, and this healing process involves the dynamic interplay between resident cells within the skin and cells recruited from the circulation. Recent studies have provided mounting evidence that external mechanical forces stimulate intracellular signaling pathways to drive fibrotic processes.INNOVATION: While most studies have focused on studying mechanotransduction in fibroblasts, recent data suggest that mechanical stimulation may also shape the behavior of immune cells, referred to as "mechano-immunomodulation". However, the effect of mechanical strain on myeloid cell recruitment and differentiation remains poorly understood and has never been investigated at the single cell level.APPROACH: In this study, we utilized a three-dimensional (3D) in vitro culture system that permits the precise manipulation of mechanical strain applied to cells. We cultured myeloid cells and used single cell RNA-sequencing to interrogate the effects of strain on myeloid differentiation and transcriptional programming.RESULTS: Our data indicate that myeloid cells are indeed mechanoresponsive, with mechanical stress influencing myeloid differentiation. Mechanical strain also upregulated a cascade of inflammatory chemokines, most notably from the Ccl family.CONCLUSION: Further understanding of how mechanical stress affects myeloid cells in conjunction with other cell types in the complicated, multicellular milieu of wound healing may lead to novel insights and therapies for the treatment of fibrosis.

  View details for DOI 10.1089/wound.2021.0036

  View details for PubMedID 34278820

• Mechanical Activation Of Inflammation At The Implant-tissue Interface Underlies Pathological Foreign Body Response Padmanabhan, J., Chen, K., Bonham, C. A., Kuehlmann, B. A., Dohi, T., Henn, D., Stern-Buchbinder, Z. A., Than, P. A., Hosseini, H. S., Magbual, N. J., Borrelli, M., Sivaraj, D., Trotsyuk, A. A., Kwon, S., Maan, Z., Januszyk, M., Prantl, L., Gurtner, G. C. WILEY. 2021: A9

  View details for Web of Science ID 000650720500032

• Single Cell RNA Sequencing Reveals Fibroblast Heterogeneity Across Embryonic Origins Of Skin Griffin, M., King, M., Chen, K., desJardins-Park, H., Mascharak, S., Fahy, E., Guardino, N., Lavin, C., Abbas, D., Januszyk, M., Wan, D., Longaker, M. WILEY. 2021: A11-A12

  View details for Web of Science ID 000650720500037

• Wnt-active Engrailed-1 Lineage-negative Fibroblasts Mediate Postnatal Skin Regeneration Mascharak, S., desJardins-Park, H. E., Januszyk, M., Chen, K., Davitt, M. F., Demeter, J., Henn, D., Griffin, M., Bonham, C. A., Mooney, N., Cheng, R., Jackson, P. K., Wan, D. C., Gurtner, G. C., Longaker, M. T. WILEY. 2021: A30

  View details for Web of Science ID 000650720500076

• CRISPR/Cas9 Editing Of Autologous Dendritic Cells To Enhance Angiogenesis And Wound Healing Henn, D., Zhao, D., Bonham, C. A., Chen, K., Greco, A. H., Padmanabhan, J., Sivaraj, D., Trotsyuk, A., Barrera, J. A., Januszyk, M., Qi, L., Gurtner, G. C. WILEY. 2021: A31-A32

  View details for Web of Science ID 000650720500079

• Disrupting Mechanotransduction Reduces Scar Formation And Restores Cellular Subpopulations In A Large Animal Model Of Skin Grafting Chen, K., Henn, D., Bonham, C. A., Noishiki, C., Barrera, J. A., Carlomagno, T. C., Shannon, T., Mays, C. J., Trotsyuk, A. A., Padmanabhan, J., Longaker, M. T., Januszyk, M., Gurtner, G. C. WILEY. 2021: A12-A13

  View details for Web of Science ID 000650720500039

• Preventing Engrailed-1 activation in fibroblasts yields wound regeneration without scarring. Science (New York, N.Y.) Mascharak, S., desJardins-Park, H. E., Davitt, M. F., Griffin, M., Borrelli, M. R., Moore, A. L., Chen, K., Duoto, B., Chinta, M., Foster, D. S., Shen, A. H., Januszyk, M., Kwon, S. H., Wernig, G., Wan, D. C., Lorenz, H. P., Gurtner, G. C., Longaker, M. T. 2021; 372 (6540)

  Abstract

  Skin scarring, the end result of adult wound healing, is detrimental to tissue form and function. Engrailed-1 lineage-positive fibroblasts (EPFs) are known to function in scarring, but Engrailed-1 lineage-negative fibroblasts (ENFs) remain poorly characterized. Using cell transplantation and transgenic mouse models, we identified a dermal ENF subpopulation that gives rise to postnatally derived EPFs by activating Engrailed-1 expression during adult wound healing. By studying ENF responses to substrate mechanics, we found that mechanical tension drives Engrailed-1 activation via canonical mechanotransduction signaling. Finally, we showed that blocking mechanotransduction signaling with either verteporfin, an inhibitor of Yes-associated protein (YAP), or fibroblast-specific transgenic YAP knockout prevents Engrailed-1 activation and promotes wound regeneration by ENFs, with recovery of skin appendages, ultrastructure, and mechanical strength. This finding suggests that there are two possible outcomes to postnatal wound healing: a fibrotic response (EPF-mediated) and a regenerative response (ENF-mediated).

  View details for DOI 10.1126/science.aba2374

  View details for PubMedID 33888614

• Adipose-derived stromal cells seeded in pullulan-collagen hydrogels improve healing in murine burns. Tissue engineering. Part A Barrera, J., Trotsyuk, A., Maan, Z. N., Bonham, C. A., Larson, M. R., Mittermiller, P. A., Henn, D., Chen, K., Mays, C. J., Mittal, S., Mermin-Bunnell, A. M., Sivaraj, D., Jing, S., Rodrigues, M., Kwon, S. H., Noishiki, C., Padmanabhan, J., Jiang, Y., Niu, S., Inayathullah, M., Rajadas, J., Januszyk, M., Gurtner, G. C. 2021

  Abstract

  Burn scars and scar contractures cause significant morbidity for patients. Recently, cell-based therapies have been proposed as an option for improving healing and reducing scarring after burn injury, through their known pro-angiogenic and immunomodulatory paracrine effects. Our lab has developed a pullulan-collagen hydrogel that, when seeded with mesenchymal stem cells (MSCs), improves cell viability and augments their pro-angiogenic capacity in vivo. Concurrently, recent research suggests that prospective isolation of cell subpopulations with desirable transcriptional profiles can be used to further improve cell-based therapies. In this study, we examined whether adipose-derived stem cell-seeded hydrogels could improve wound healing following thermal injury using a murine contact burn model. Partial thickness contact burns were created on the dorsum of mice. On days 5 and 10 following injury, burns were debrided and received either ASC-hydrogel, ASC injection alone, hydrogel alone, or no treatment. On days 10 and 25, burns were harvested for histologic and molecular analysis. This experiment was repeated using CD26+/CD55+ FACS-enriched ASCs to further evaluate the regenerative potential of ASCs in wound healing. ASC-hydrogel-treated burns demonstrated accelerated time to re-epithelialization, greater vascularity, and increased expression of the pro-angiogenic genes MCP-1, VEGF, and SDF-1 at both the mRNA and protein level. Expression of the pro-fibrotic gene Timp1 and pro-inflammatory gene Tnfa were down-regulated in ASC-hydrogel treated burns. ASC-hydrogel treated burns exhibited reduced scar area compared to hydrogel-treated and control wounds, with equivalent scar density. CD26+/CD55+ ASC-hydrogel treatment resulted in accelerated healing, increased dermal appendage count, and improved scar quality with a more reticular collagen pattern. Here we find that ASC-hydrogel therapy is effective for treating burns, with demonstrated pro-angiogenic, fibro-modulatory and immunomodulatory effects. Enrichment for CD26+/CD55+ ASCs has additive benefits for tissue architecture and collagen remodeling post-burn injury. Research is ongoing to further facilitate clinical translation of this promising therapeutic approach.

  View details for DOI 10.1089/ten.TEA.2020.0320

  View details for PubMedID 33789446

• Flap Neurotization in Breast Reconstruction with Nerve Allografts: 1-year Clinical Outcomes. Plastic and reconstructive surgery. Global open Momeni, A., Meyer, S., Shefren, K., Januszyk, M. 2021; 9 (1): e3328

  Abstract

  Autologous breast reconstruction is widely regarded as the gold standard approach following mastectomy. However, the lack of sensation continues to present a reconstructive challenge. In this study, clinical outcomes following abdominal flap neurotization with processed human nerve allograft were investigated.Methods: In this prospective analysis, patients who underwent microsurgical breast reconstruction with (Group 1) or without (Group 2) abdominal flap neurotization at a single institution were investigated. Processed human nerve allograft (Avance, AxoGen, Alachua, Fla.) was used in all cases of flap neurotization. Only patients with a follow-up of ≥12 months were included. Cutaneous pressure threshold was tested using Semmes-Weinstein monofilaments (SWMF) at 9 pre-defined locations.Results: A total of 59 patients (96 breasts) were enrolled into the registry. Of these, 22 patients (Group 1: N = 15, 22 breasts; Group 2: N = 7, 14 breasts) had a complete data set with ≥12 months follow-up. Measuring cutaneous pressure thresholds, we observed a greater likelihood for return of protective sensation (SWMF ≤ 4.31) in neurotized breasts in 8 of the 9 examined zones. Additionally, flap neurotization was associated with a greater likelihood for return of protective sensation in the majority of the reconstructed breast-that is, ≥5 zones (55% versus 7%; P < 0.01).Conclusion: Flap neurotization using processed nerve allograft resulted in a greater degree of return of protective sensation to the reconstructed breast than reconstructions without neurotization at ≥12 months.

  View details for DOI 10.1097/GOX.0000000000003328

  View details for PubMedID 33564572

• Hydrogel Scaffolds to Deliver Cell Therapies for Wound Healing. Frontiers in bioengineering and biotechnology Sivaraj, D., Chen, K., Chattopadhyay, A., Henn, D., Wu, W., Noishiki, C., Magbual, N. J., Mittal, S., Mermin-Bunnell, A. M., Bonham, C. A., Trotsyuk, A. A., Barrera, J. A., Padmanabhan, J., Januszyk, M., Gurtner, G. C. 2021; 9: 660145

  Abstract

  Cutaneous wounds are a growing global health burden as a result of an aging population coupled with increasing incidence of diabetes, obesity, and cancer. Cell-based approaches have been used to treat wounds due to their secretory, immunomodulatory, and regenerative effects, and recent studies have highlighted that delivery of stem cells may provide the most benefits. Delivering these cells to wounds with direct injection has been associated with low viability, transient retention, and overall poor efficacy. The use of bioactive scaffolds provides a promising method to improve cell therapy delivery. Specifically, hydrogels provide a physiologic microenvironment for transplanted cells, including mechanical support and protection from native immune cells, and cell-hydrogel interactions may be tailored based on specific tissue properties. In this review, we describe the current and future directions of various cell therapies and usage of hydrogels to deliver these cells for wound healing applications.

  View details for DOI 10.3389/fbioe.2021.660145

  View details for PubMedID 34012956

• Disrupting biological sensors of force promotes tissue regeneration in large organisms. Nature communications Chen, K., Kwon, S. H., Henn, D., Kuehlmann, B. A., Tevlin, R., Bonham, C. A., Griffin, M., Trotsyuk, A. A., Borrelli, M. R., Noishiki, C., Padmanabhan, J., Barrera, J. A., Maan, Z. N., Dohi, T., Mays, C. J., Greco, A. H., Sivaraj, D., Lin, J. Q., Fehlmann, T., Mermin-Bunnell, A. M., Mittal, S., Hu, M. S., Zamaleeva, A. I., Keller, A., Rajadas, J., Longaker, M. T., Januszyk, M., Gurtner, G. C. 2021; 12 (1): 5256

  Abstract

  Tissue repair and healing remain among the most complicated processes that occur during postnatal life. Humans and other large organisms heal by forming fibrotic scar tissue with diminished function, while smaller organisms respond with scarless tissue regeneration and functional restoration. Well-established scaling principles reveal that organism size exponentially correlates with peak tissue forces during movement, and evolutionary responses have compensated by strengthening organ-level mechanical properties. How these adaptations may affect tissue injury has not been previously examined in large animals and humans. Here, we show that blocking mechanotransduction signaling through the focal adhesion kinase pathway in large animals significantly accelerates wound healing and enhances regeneration of skin with secondary structures such as hair follicles. In human cells, we demonstrate that mechanical forces shift fibroblasts toward pro-fibrotic phenotypes driven by ERK-YAP activation, leading to myofibroblast differentiation and excessive collagen production. Disruption of mechanical signaling specifically abrogates these responses and instead promotes regenerative fibroblast clusters characterized by AKT-EGR1.

  View details for DOI 10.1038/s41467-021-25410-z

  View details for PubMedID 34489407

• Xenogeneic skin transplantation promotes angiogenesis and tissue regeneration through activated Trem2+ macrophages. Science advances Henn, D., Chen, K., Fehlmann, T., Trotsyuk, A. A., Sivaraj, D., Maan, Z. N., Bonham, C. A., Barrera, J. A., Mays, C. J., Greco, A. H., Moortgat Illouz, S. E., Lin, J. Q., Steele, S. R., Foster, D. S., Padmanabhan, J., Momeni, A., Nguyen, D., Wan, D. C., Kneser, U., Januszyk, M., Keller, A., Longaker, M. T., Gurtner, G. C. 2021; 7 (49): eabi4528

  Abstract

  [Figure: see text].

  View details for DOI 10.1126/sciadv.abi4528

  View details for PubMedID 34851663

• Epidermal-Derived Hedgehog Signaling Drives Mesenchymal Proliferation during Digit Tip Regeneration. Journal of clinical medicine Maan, Z. N., Rinkevich, Y., Barrera, J., Chen, K., Henn, D., Foster, D., Bonham, C. A., Padmanabhan, J., Sivaraj, D., Duscher, D., Hu, M., Yan, K., Januszyk, M., Longaker, M. T., Weissman, I. L., Gurtner, G. C. 2021; 10 (18)

  Abstract

  Hand injuries often result in significant functional impairments and are rarely completely restored. The spontaneous regeneration of injured appendages, which occurs in salamanders and newts, for example, has been reported in human fingertips after distal amputation, but this type of regeneration is rare in mammals and is incompletely understood. Here, we study fingertip regeneration by amputating murine digit tips, either distally to initiate regeneration, or proximally, causing fibrosis. Using an unbiased microarray analysis, we found that digit tip regeneration is significantly associated with hair follicle differentiation, Wnt, and sonic hedgehog (SHH) signaling pathways. Viral over-expression and genetic knockouts showed the functional significance of these pathways during regeneration. Using transgenic reporter mice, we demonstrated that, while both canonical Wnt and HH signaling were limited to epidermal tissues, downstream hedgehog signaling (through Gli) occurred in mesenchymal tissues. These findings reveal a mechanism for epidermal/mesenchyme interactions, governed by canonical hedgehog signaling, during digit regeneration. Further research into these pathways could lead to improved therapeutic outcomes after hand injuries in humans.

  View details for DOI 10.3390/jcm10184261

  View details for PubMedID 34575372

• Discussion: Overcoming the Patent Gap: A Guide to Patenting for Plastic Surgeons. Plastic and reconstructive surgery Januszyk, M., desJardins-Park, H. E., Gurtner, G. C., Longaker, M. T. 2021; 148 (4): 918-919

  View details for DOI 10.1097/PRS.0000000000008394

  View details for PubMedID 34550949

• Prrx1 Fibroblasts Represent a Pro-fibrotic Lineage in the Mouse Ventral Dermis. Cell reports Leavitt, T., Hu, M. S., Borrelli, M. R., Januszyk, M., Garcia, J. T., Ransom, R. C., Mascharak, S., desJardins-Park, H. E., Litzenburger, U. M., Walmsley, G. G., Marshall, C. D., Moore, A. L., Duoto, B., Adem, S., Foster, D. S., Salhotra, A., Shen, A. H., Griffin, M., Shen, E. Z., Barnes, L. A., Zielins, E. R., Maan, Z. N., Wei, Y., Chan, C. K., Wan, D. C., Lorenz, H. P., Chang, H. Y., Gurtner, G. C., Longaker, M. T. 2020; 33 (6): 108356

  Abstract

  Fibroblast heterogeneity has been shown within the unwounded mouse dorsal dermis, with fibroblast subpopulations being identified according to anatomical location and embryonic lineage. Using lineage tracing, we demonstrate that paired related homeobox 1 (Prrx1)-expressing fibroblasts are responsible for acute and chronic fibroses in the ventral dermis. Single-cell transcriptomics further corroborated the inherent fibrotic characteristics of Prrx1 fibroblasts during wound repair. In summary, we identify and characterize a fibroblast subpopulation in the mouse ventral dermis with intrinsic scar-forming potential.

  View details for DOI 10.1016/j.celrep.2020.108356

  View details for PubMedID 33176144

• Ectoderm-Derived Wnt and Hedgehog Signaling Drive Digit Tip Regeneration Barrera, J., Maan, Z. N., Foster, D., Henn, D., Chen, K., Bonham, C., Januszyk, M., Longaker, M. T., Weissman, I., Gurtner, G. C. ELSEVIER SCIENCE INC. 2020: S186

  View details for Web of Science ID 000582792300339

• Wounds Heal by Tissue-Resident Fibroblast Progenitors that Proliferate Polyclonally and Mechanoresponsively Foster, D. S., Chinta, M., Salhotra, A., Nguyen, A. T., Burcham, A., Mascharak, S., Januszyk, M., Gurtner, G. C., Wernig, G., Longaker, M. T. ELSEVIER SCIENCE INC. 2020: S236–S237

  View details for Web of Science ID 000582792300433

• Single-Cell RNA Sequencing Uncovers Antifibrotic Subpopulations of Macrophages in the Cellular Response to Skin Xenografts Henn, D., Chen, K., Maan, Z., Illouz, S., Bonham, C. A., Barrera, J. A., Momeni, A., Wan, D. C., Januszyk, M., Gurtner, G. C. ELSEVIER SCIENCE INC. 2020: S232

  View details for Web of Science ID 000582792300425

• Characterization of Diabetic and Non-Diabetic Foot Ulcers Using Single-Cell RNA-Sequencing. Micromachines Januszyk, M., Chen, K., Henn, D., Foster, D. S., Borrelli, M. R., Bonham, C. A., Sivaraj, D., Wagh, D., Longaker, M. T., Wan, D. C., Gurtner, G. C. 2020; 11 (9)

  Abstract

  Background: Recent advances in high-throughput single-cell sequencing technologies have led to their increasingly widespread adoption for clinical applications. However, challenges associated with tissue viability, cell yield, and delayed time-to-capture have created unique obstacles for data processing. Chronic wounds, in particular, represent some of the most difficult target specimens, due to the significant amount of fibrinous debris, extracellular matrix components, and non-viable cells inherent in tissue routinely obtained from debridement. Methods: Here, we examined the feasibility of single cell RNA sequencing (scRNA-seq) analysis to evaluate human chronic wound samples acquired in the clinic, subjected to prolonged cold ischemia time, and processed without FACS sorting. Wound tissue from human diabetic and non-diabetic plantar foot ulcers were evaluated using an optimized 10X Genomics scRNA-seq platform and analyzed using a modified data pipeline designed for low-yield specimens. Cell subtypes were identified informatically and their distributions and transcriptional programs were compared between diabetic and non-diabetic tissue. Results: 139,000 diabetic and non-diabetic wound cells were delivered for 10X capture after either 90 or 180 min of cold ischemia time. cDNA library concentrations were 858.7 and 364.7 pg/L, respectively, prior to sequencing. Among all barcoded fragments, we found that 83.5% successfully aligned to the human transcriptome and 68% met the minimum cell viability threshold. The average mitochondrial mRNA fraction was 8.5% for diabetic cells and 6.6% for non-diabetic cells, correlating with differences in cold ischemia time. A total of 384 individual cells were of sufficient quality for subsequent analyses; from this cell pool, we identified transcriptionally-distinct cell clusters whose gene expression profiles corresponded to fibroblasts, keratinocytes, neutrophils, monocytes, and endothelial cells. Fibroblast subpopulations with differing fibrotic potentials were identified, and their distributions were found to be altered in diabetic vs. non-diabetic cells. Conclusions: scRNA-seq of clinical wound samples can be achieved using minor modifications to standard processing protocols and data analysis methods. This simple approach can capture widespread transcriptional differences between diabetic and non-diabetic tissue obtained from matched wound locations.

  View details for DOI 10.3390/mi11090815

  View details for PubMedID 32872278

• An artificial intelligence based meta-analysis of publicly available single cell RNA-seq datasets for hematopoietic and lymphoid malignancies identifies repurposable cancer drug targets Jiang, B., Januszyk, M. AMER ASSOC CANCER RESEARCH. 2020

  View details for DOI 10.1158/1538-7445.AM2020-4166A

  View details for Web of Science ID 000590059305442

• Prophylactic treatment with transdermal deferoxamine mitigates radiation-induced skin fibrosis. Scientific reports Shen, A. H., Borrelli, M. R., Adem, S., Deleon, N. M., Patel, R. A., Mascharak, S., Yen, S. J., Sun, B. Y., Taylor, W. L., Januszyk, M., Nguyen, D. H., Momeni, A., Gurtner, G. C., Longaker, M. T., Wan, D. C. 2020; 10 (1): 12346

  Abstract

  Radiation therapy can result in pathological fibrosis of healthy soft tissue. The iron chelator deferoxamine (DFO) has been shown to improve skin vascularization when injected into radiated tissue prior to fat grafting. Here, we evaluated whether topical DFO administration using a transdermal drug delivery system prior to and immediately following irradiation (IR) can mitigate the chronic effects of radiation damage to the skin. CD-1 nude immunodeficient mice were split into four experimental groups: (1) IR alone (IR only), (2) DFO treatment for two weeks after recovery from IR (DFO post-IR), (3) DFO prophylaxis with treatment through and post-IR (DFO ppx), or (4) no irradiation or DFO (No IR). Immediately following IR, reactive oxygen species and apoptotic markers were significantly decreased and laser doppler analysis revealed significantly improved skin perfusion in mice receiving prophylactic DFO. Six weeks following IR, mice in the DFO post-IR and DFO ppx groups had improved skin perfusion and increased vascularization. DFO-treated groups also had evidence of reduced dermal thickness and collagen fiber network organization akin to non-irradiated skin. Thus, transdermal delivery of DFO improves tissue perfusion and mitigates chronic radiation-induced skin fibrosis, highlighting a potential role for DFO in the treatment of oncological patients.

  View details for DOI 10.1038/s41598-020-69293-4

  View details for PubMedID 32704071

• Inhibiting mechanotransduction signaling changes fibroblast heterogeneity and promotes tissue regeneration in healing wounds Chen, K., Kwon, S., Henn, D., Kuehlmann, B. A., Bonham, C. A., Padmanabhan, J., Noishiki, C., Barrera, J., Longaker, M. T., Januszyk, M., Gurtner, G. C. WILEY. 2020: S12–S13

  View details for Web of Science ID 000548418300023

• Radiation-induced skin fibrosis is reversed by transdermal delivery of deferoxamine Borrelli, M. R., Adem, S., Diaz, N., Mascharak, S., Sen, A., Januszyk, M., Nguyen, D., Momeni, A., Gurtner, G. C., Longaker, M. T., Wan, D. C. WILEY. 2020: S51–S52

  View details for Web of Science ID 000548418300116

• Stretch marks are abundant in CD26-positive human dermal fibroblasts and exhibit increased profibrotic mechanosensitive signaling Borrelli, M. R., Griffin, M., Ngaage, L. M., Mascharak, S., Lewis, N., Januszyk, M., Wan, D. C., Longaker, M. T., Lorenz, H. P. WILEY. 2020: S32

  View details for Web of Science ID 000548418300069

• Flexible smart bandage for wireless wound healing Trotsyuk, A. A., Jiang, Y., Niu, S., Larson, M., Beard, E., Saberi, A., Henn, D., Kwon, S., Bonham, C., Chen, K., Januszyk, M., Maan, Z., Barrera, J., Padmanabhan, J., Fischer, K. S., Bao, Z., Gurtner, G. C. WILEY. 2020: S24

  View details for Web of Science ID 000548418300050

• Digit tip regeneration relies on germ layer restricted Wnt and Hedgehog signaling Barrera, J., Maan, Z., Rinkevich, Y., Henn, D., Chen, K., Bonham, C. A., Padmanabhan, J., Januszyk, M., Weissman, I. L., Gurtner, G. C. WILEY. 2020: S5

  View details for Web of Science ID 000548418300006

• Human cryopreserved skingrafts recruit M2-macrophages and induce angiogenesis in a murine xenograft model Henn, D., Chen, K., Maan, Z. N., Illouz, S., Bonham, C. A., Fischer, K. S., Padmanabhan, J., Barrera, J. A., Wan, D. C., Januszyk, M., Gurtner, G. C. WILEY. 2020: S62–S63

  View details for Web of Science ID 000548418300144

• Inhibiting mechanotransduction signaling changes fibroblast heterogeneity and promotes tissue regeneration in healing wounds Chen, K., Kwon, S., Henn, D., Kuehlmann, B. A., Bonham, C. A., Padmanabhan, J., Noishiki, C., Barrera, J., Longaker, M. T., Januszyk, M., Gurtner, G. C. WILEY. 2020: S13–S14

  View details for Web of Science ID 000548418300026

• Cryopreserved human skin allografts promote angiogenesis and dermal regeneration in a murine model. International wound journal Henn, D. n., Chen, K. n., Maan, Z. N., Greco, A. H., Moortgat Illouz, S. E., Bonham, C. A., Barrera, J. A., Trotsyuk, A. A., Padmanabhan, J. n., Momeni, A. n., Wan, D. C., Nguyen, D. n., Januszyk, M. n., Gurtner, G. C. 2020

  Abstract

  Cryopreserved human skin allografts (CHSAs) are used for the coverage of major burns when donor sites for autografts are insufficiently available and have clinically shown beneficial effects on chronic non-healing wounds. However, the biologic mechanisms behind the regenerative properties of CHSA remain elusive. Furthermore, the impact of cryopreservation on the immunogenicity of CHSA has not been thoroughly investigated and raised concerns with regard to their clinical application. To investigate the importance and fate of living cells, we compared cryopreserved CHSA with human acellular dermal matrix (ADM) grafts in which living cells had been removed by chemical processing. Both grafts were subcutaneously implanted into C57BL/6 mice and explanted after 1, 3, 7, and 28 days (n = 5 per group). A sham surgery where no graft was implanted served as a control. Transmission electron microscopy (TEM) and flow cytometry were used to characterise the ultrastructure and cells within CHSA before implantation. Immunofluorescent staining of tissue sections was used to determine the immune reaction against the implanted grafts, the rate of apoptotic cells, and vascularisation as well as collagen content of the overlaying murine dermis. Digital quantification of collagen fibre alignment on tissue sections was used to quantify the degree of fibrosis within the murine dermis. A substantial population of live human cells with intact organelles was identified in CHSA prior to implantation. Subcutaneous pockets with implanted xenografts or ADMs healed without clinically apparent rejection and with a similar cellular immune response. CHSA implantation largely preserved the cellularity of the overlying murine dermis, whereas ADM was associated with a significantly higher rate of cellular apoptosis, identified by cleaved caspase-3 staining, and a stronger dendritic cell infiltration of the murine dermis. CHSA was found to induce a local angiogenic response, leading to significantly more vascularisation of the murine dermis compared with ADM and sham surgery on day 7. By day 28, aggregate collagen-1 content within the murine dermis was greater following CHSA implantation compared with ADM. Collagen fibre alignment of the murine dermis, correlating with the degree of fibrosis, was significantly greater in the ADM group, whereas CHSA maintained the characteristic basket weave pattern of the native murine dermis. Our data indicate that CHSAs promote angiogenesis and collagen-1 production without eliciting a significant fibrotic response in a xenograft model. These findings may provide insight into the beneficial effects clinically observed after treatment of chronic wounds and burns with CHSA.

  View details for DOI 10.1111/iwj.13349

  View details for PubMedID 32227459

• Elucidating the fundamental fibrotic processes driving abdominal adhesion formation. Nature communications Foster, D. S., Marshall, C. D., Gulati, G. S., Chinta, M. S., Nguyen, A. n., Salhotra, A. n., Jones, R. E., Burcham, A. n., Lerbs, T. n., Cui, L. n., King, M. E., Titan, A. L., Ransom, R. C., Manjunath, A. n., Hu, M. S., Blackshear, C. P., Mascharak, S. n., Moore, A. L., Norton, J. A., Kin, C. J., Shelton, A. A., Januszyk, M. n., Gurtner, G. C., Wernig, G. n., Longaker, M. T. 2020; 11 (1): 4061

  Abstract

  Adhesions are fibrotic scars that form between abdominal organs following surgery or infection, and may cause bowel obstruction, chronic pain, or infertility. Our understanding of adhesion biology is limited, which explains the paucity of anti-adhesion treatments. Here we present a systematic analysis of mouse and human adhesion tissues. First, we show that adhesions derive primarily from the visceral peritoneum, consistent with our clinical experience that adhesions form primarily following laparotomy rather than laparoscopy. Second, adhesions are formed by poly-clonal proliferating tissue-resident fibroblasts. Third, using single cell RNA-sequencing, we identify heterogeneity among adhesion fibroblasts, which is more pronounced at early timepoints. Fourth, JUN promotes adhesion formation and results in upregulation of PDGFRA expression. With JUN suppression, adhesion formation is diminished. Our findings support JUN as a therapeutic target to prevent adhesions. An anti-JUN therapy that could be applied intra-operatively to prevent adhesion formation could dramatically improve the lives of surgical patients.

  View details for DOI 10.1038/s41467-020-17883-1

  View details for PubMedID 32792541

• Digit Tip Regeneration Relies on Germ Layer Restricted Wnt and Hedgehog Signaling Maan, Z. N., Januszyk, M., Rinkevich, Y., Weissman, I., Gurtner, G. ELSEVIER SCIENCE INC. 2019: S220–S221

  View details for Web of Science ID 000492740900422

• Small molecule inhibition of dipeptidyl peptidase-4 enhances bone marrow progenitor cell function and angiogenesis in diabetic wounds TRANSLATIONAL RESEARCH Whittam, A. J., Maan, Z. N., Duscher, D., Barrera, J. A., Hu, M. S., Fischer, L. H., Khong, S., Kwon, S., Wong, V. W., Walmsley, G. G., Giacco, F., Januszyk, M., Brownlee, M., Longaker, M. T., Gurtner, G. C. 2019; 205: 51–63

  View details for DOI 10.1016/j.trsl.2018.10.006

  View details for Web of Science ID 000459843700005

• Small molecule inhibition of dipeptidyl peptidase-4 enhances bone marrow progenitor cell function and angiogenesis in diabetic wounds. Translational research : the journal of laboratory and clinical medicine Whittam, A. J., Maan, Z. N., Duscher, D., Barrera, J. A., Hu, M. S., Fischer, L. H., Khong, S., Kwon, S. H., Wong, V. W., Walmsley, G. G., Giacco, F., Januszyk, M., Brownlee, M., Longaker, M. T., Gurtner, G. C. 2018

  Abstract

  In diabetes, stromal cell-derived factor-1 (SDF-1) expression and progenitor cell recruitment are reduced. Dipeptidyl peptidase-4 (DPP-4) inhibits SDF-1 expression and progenitor cell recruitment. Here we examined the impact of the DPP-4 inhibitor, MK0626, on progenitor cell kinetics in the context of wound healing. Wildtype (WT) murine fibroblasts cultured under high-glucose to reproduce a diabetic microenvironment were exposed to MK0626, glipizide, or no treatment, and SDF-1 expression was measured with ELISA. Diabetic mice received MK0626, glipizide, or no treatment for 6 weeks and then were wounded. Immunohistochemistry was used to quantify neovascularization and SDF-1 expression. Gene expression was measured at the RNA and protein level using quantitative polymerase chain reaction and ELISA, respectively. Flow cytometry was used to characterize bone marrow-derived mesenchymal progenitor cell (BM-MPC) population recruitment to wounds. BM-MPC gene expression was assayed using microfluidic single cell analysis. WT murine fibroblasts exposed to MK0626 demonstrated increased SDF-1 expression. MK0626 treatment significantly accelerated wound healing and increased wound vascularity, SDF-1 expression, and dermal thickness in diabetic wounds. MK0626 treatment increased the number of BM-MPCs present in bone marrow and in diabetic wounds. MK0626 had no effect on BM-MPC population dynamics. BM-MPCs harvested from MK0626-treated mice exhibited increased chemotaxis in response to SDF-1 when compared to diabetic controls. Treatment with a DPP-4 inhibitor significantly improved wound healing, angiogenesis, and endogenous progenitor cell recruitment in the setting of diabetes.

  View details for PubMedID 30452888

• Pathway Analysis of Gene Expression in Murine Fetal and Adult Wounds. Advances in wound care Hu, M. S., Hong, W. X., Januszyk, M., Walmsley, G. G., Luan, A., Maan, Z. N., Moshrefi, S., Tevlin, R., Wan, D. C., Gurtner, G. C., Longaker, M. T., Lorenz, H. P. 2018; 7 (8): 262-275

  Abstract

  Objective: In early gestation, fetal wounds heal without fibrosis in a process resembling regeneration. Elucidating this remarkable mechanism can result in tremendous benefits to prevent scarring. Fetal mouse cutaneous wounds before embryonic day (E)18 heal without scar. Herein, we analyze expression profiles of fetal and postnatal wounds utilizing updated gene annotations and pathway analysis to further delineate between repair and regeneration. Approach: Dorsal wounds from time-dated pregnant BALB/c mouse fetuses and adult mice at various time points were collected. Total RNA was isolated and microarray analysis was performed using chips with 42,000 genes. Significance analysis of microarrays was utilized to select genes with >2-fold expression differences with a false discovery rate of <2. Enrichment analysis was performed on significant genes to identify differentially expressed pathways. Results: Our analysis identified 471 differentially expressed genes in fetal versus adult wounds following injury. Utilizing enrichment analysis of significant genes, we identified the top 20 signaling pathways that were upregulated and downregulated at 1 and 12 h after injury. At 24 h after injury, we discovered 18 signaling pathways upregulated in adult wounds and 11 pathways upregulated in fetal wounds. Innovation: These novel target genes and pathways may reveal repair mechanisms of the early fetus that promote regeneration over fibrosis. Conclusion: Our microarray analysis recognizes hundreds of possible genes as candidates for regulators of scarless versus scarring wound repair. Enrichment analysis reveals 109 signaling pathways related to fetal scarless wound healing.

  View details for DOI 10.1089/wound.2017.0779

  View details for PubMedID 30087802

  View details for PubMedCentralID PMC6080120

• Pathway Analysis of Gene Expression in Murine Fetal and Adult Wounds ADVANCES IN WOUND CARE Hu, M. S., Hong, W., Januszyk, M., Walmsley, G. G., Luan, A., Maan, Z. N., Moshrefi, S., Tevlin, R., Wan, D. C., Gurtner, G. C., Longaker, M. T., Lorenz, H. 2018

  View details for DOI 10.1089/wound.2017.0779

  View details for Web of Science ID 000429548900001

• Pathway Analysis of Gene Expression of E14 Versus E18 Fetal Fibroblasts ADVANCES IN WOUND CARE Hu, M. S., Borrelli, M. R., Januszyk, M., Luan, A., Malhotra, S., Walmsley, G. G., Hong, W., Tevlin, R., Gurtner, G. C., Longaker, M. T., Lorenz, H. P. 2018; 7 (1): 1–10

  Abstract

  Objective: Fetuses early in gestation heal skin wounds without forming scars. The biological mechanisms behind this process are largely unknown. Fibroblasts, however, are cells known to be intimately involved in wound healing and scar formation. We examined fibroblasts in different stages of development to characterize differences in gene expression that may result in the switch from regenerative wound repair to repair with scarring. Approach: Fibroblasts were isolated and cultured from the back skin of BALB/c wild-type mouse fetuses at embryonic day (E)14 and E18 (n = 10). The fibroblast total RNA was extracted, and microarray analysis was conducted using chips containing 42,000 genes. Significance analysis of microarrays was performed to identify genes with greater than twofold expression difference and a false discovery rate of less than two. Identified genes subsequently underwent enrichment analysis to detect differentially expressed pathways. Results: Two hundred seventy-five genes were differentially expressed between E14 and E18 in fetal fibroblasts. Thirty genes were significantly downregulated and 245 genes were significantly upregulated at E18 compared with E14. Ingenuity pathway analysis identified the top 20 signaling pathways differentially activated in fetal fibroblasts between the E18 and E14 time points. Innovation: To our knowledge, this work represents the first instance where differentially expressed genes and signaling pathways between fetal fibroblasts at E14 and E18 have been studied. Conclusion: The genes and pathways identified here potentially underlie the mechanism behind the transition from fetal wound healing via regeneration to wound healing by repair, and may prove to be key targets for future therapeutics.

  View details for PubMedID 29344429

• Is Distraction Osteogenesis of the Irradiated Craniofacial Skeleton Contraindicated? JOURNAL OF CRANIOFACIAL SURGERY Momeni, A., Januszyk, M., Wan, D. C. 2017; 28 (5): 1236–41

  Abstract

  Craniofacial distraction osteogenesis (DO) is a common treatment modality today. Despite its numerous advantages, however, concerns have been expressed regarding the use of DO in the irradiated setting.A systematic review was performed to identify all published reports of patients who underwent DO of the irradiated craniofacial skeleton. The following parameters were of particular interest: postoperative complications, specifically, insufficient bone formation, fracture, and hardware exposure (intraoral and cutaneous), as well as the need for additional bone grafting.The initial search retrieved a total of 183 articles of which 20 articles (38 patients) met predetermined inclusion criteria. The most common site of distraction was the mandible (76.3%). The median radiation dose was 50.7 Gy (range, 30-70 Gy). Bone defects ranged from 30 to 80 mm (median, 42.5 mm). Complications were encountered in 19 patients (50%), with insufficient bone formation being most common (9 patients; 23%). The overall incidence of complications was not significantly associated with radiation dosage (P = 0.79). The remaining procedural and demographic variables also failed to meet statistical significance when compared against the overall complication rate (P = 0.27-0.97).The complication rate associated with craniofacial DO of the irradiated skeleton does not appear to be substantially higher than what is reported for DO in the nonirradiated setting. As such, patients should be offered this treatment modality, particularly in light of the fact, that it offers the option to decrease patient morbidity as well as treatment complexity.

  View details for PubMedID 28665865

• Isolation of CD248-expressing stromal vascular fraction for targeted improvement of wound healing. Wound repair and regeneration Brett, E., Zielins, E. R., Chin, M., Januszyk, M., Blackshear, C. P., Findlay, M., Momeni, A., Gurtner, G. C., Longaker, M. T., Wan, D. C. 2017

  Abstract

  Wound healing remains a global issue of disability, cost, and health. Addition of cells from the stromal vascular fraction (SVF) of adipose tissue has been shown to increase the rate of full thickness wound closure. This study aimed to investigate the angiogenic mechanisms of CD248+ SVF cells in the context of full thickness excisional wounds. Single cell transcriptional analysis was used to identify and cluster angiogenic gene-expressing cells, which was then correlated with surface marker expression. SVF cells isolated from human lipoaspirate were FACS sorted based on the presence of CD248. Cells were analyzed for angiogenic gene expression and ability to promote microvascular tubule formation in vitro. Following this, 6mm full thickness dermal wounds were created on the dorsa of immunocompromised mice and then treated with CD248+, CD248-, or unsorted SVF cells delivered in a pullalan-collagen hydrogel or the hydrogel alone. Wounds were measured every other day photometrically until closure. Wounds were also evaluated histologically at 7 and 14 days post-wounding and when fully healed to assess for reepithelialization and development of neovasculature. Wounds treated with CD248+ cells healed significantly faster than other treatment groups, and at 7 days, had quantitatively more reepithelialization. Concurrently, immunohistochemistry of CD31 revealed a much higher presence of vascularity in the CD248+ SVF cells treated group at the time of healing and at 14 days post-op, consistent with a pro-angiogenic effect of CD248+ cells in vivo. Therefore, using CD248+ pro-angiogenic cells obtained from SVF presents a viable strategy in wound healing by promoting increased vessel growth in the wound.

  View details for DOI 10.1111/wrr.12542

  View details for PubMedID 28464475

• Comparison of the Hydroxylase Inhibitor Dimethyloxalylglycine and the Iron Chelator Deferoxamine in Diabetic and Aged Wound Healing. Plastic and reconstructive surgery Duscher, D., Januszyk, M., Maan, Z. N., Whittam, A. J., Hu, M. S., Walmsley, G. G., Dong, Y., Khong, S. M., Longaker, M. T., Gurtner, G. C. 2017; 139 (3): 695e-706e

  Abstract

  A hallmark of diabetes mellitus is the breakdown of almost every reparative process in the human body, leading to critical impairments of wound healing. Stabilization and activity of the transcription factor hypoxia-inducible factor (HIF)-1α is impaired in diabetes, leading to deficits in new blood vessel formation in response to injury. In this article, the authors compare the effectiveness of two promising small-molecule therapeutics, the hydroxylase inhibitor dimethyloxalylglycine and the iron chelator deferoxamine, for attenuating diabetes-associated deficits in cutaneous wound healing by enhancing HIF-1α activation.HIF-1α stabilization, phosphorylation, and transactivation were measured in murine fibroblasts cultured under normoxic or hypoxic and low-glucose or high-glucose conditions following treatment with deferoxamine or dimethyloxalylglycine. In addition, diabetic wound healing and neovascularization were evaluated in db/db mice treated with topical solutions of either deferoxamine or dimethyloxalylglycine, and the efficacy of these molecules was also compared in aged mice.The authors show that deferoxamine stabilizes HIF-1α expression and improves HIF-1α transactivity in hypoxic and hyperglycemic states in vitro, whereas the effects of dimethyloxalylglycine are significantly blunted under hyperglycemic hypoxic conditions. In vivo, both dimethyloxalylglycine and deferoxamine enhance wound healing and vascularity in aged mice, but only deferoxamine universally augmented wound healing and neovascularization in the setting of both advanced age and diabetes.This first direct comparison of deferoxamine and dimethyloxalylglycine in the treatment of impaired wound healing suggests significant therapeutic potential for topical deferoxamine treatment in ischemic and diabetic disease.

  View details for DOI 10.1097/PRS.0000000000003072

  View details for PubMedID 28234841

  View details for PubMedCentralID PMC5327844

• Pharmacological rescue of diabetic skeletal stem cell niches. Science translational medicine Tevlin, R., Seo, E. Y., Marecic, O., McArdle, A., Tong, X., Zimdahl, B., Malkovskiy, A., Sinha, R., Gulati, G., Li, X., Wearda, T., Morganti, R., Lopez, M., Ransom, R. C., Duldulao, C. R., Rodrigues, M., Nguyen, A., Januszyk, M., Maan, Z., Paik, K., Yapa, K., Rajadas, J., Wan, D. C., Gurtner, G. C., Snyder, M., Beachy, P. A., Yang, F., Goodman, S. B., Weissman, I. L., Chan, C. K., Longaker, M. T. 2017; 9 (372)

  Abstract

  Diabetes mellitus (DM) is a metabolic disease frequently associated with impaired bone healing. Despite its increasing prevalence worldwide, the molecular etiology of DM-linked skeletal complications remains poorly defined. Using advanced stem cell characterization techniques, we analyzed intrinsic and extrinsic determinants of mouse skeletal stem cell (mSSC) function to identify specific mSSC niche-related abnormalities that could impair skeletal repair in diabetic (Db) mice. We discovered that high serum concentrations of tumor necrosis factor-α directly repressed the expression of Indian hedgehog (Ihh) in mSSCs and in their downstream skeletogenic progenitors in Db mice. When hedgehog signaling was inhibited during fracture repair, injury-induced mSSC expansion was suppressed, resulting in impaired healing. We reversed this deficiency by precise delivery of purified Ihh to the fracture site via a specially formulated, slow-release hydrogel. In the presence of exogenous Ihh, the injury-induced expansion and osteogenic potential of mSSCs were restored, culminating in the rescue of Db bone healing. Our results present a feasible strategy for precise treatment of molecular aberrations in stem and progenitor cell populations to correct skeletal manifestations of systemic disease.

  View details for DOI 10.1126/scitranslmed.aag2809

  View details for PubMedID 28077677

• Pharmacological rescue of diabetic skeletal stem cell niches SCIENCE TRANSLATIONAL MEDICINE Tevlin, R., Seo, E., Marecic, O., McArdle, A., Tong, X., Zimdahl, B., Malkovskiy, A., Sinha, R., Gulati, G., Li, X., Wearda, T., Morganti, R., Lopez, M., Ransom, R. C., Duldulao, C. R., Rodrigues, M., Nguyen, A., Januszyk, M., Maan, Z., Paik, K., Yapa, K., Rajadas, J., Wan, D. C., Gurtner, G. C., Snyder, M., Beachy, P. A., Yang, F., Goodman, S. B., Weissman, I. L., Chan, C. F., Longaker, M. T. 2017; 9 (372)

  View details for DOI 10.1126/scitranslmed.aag2809

  View details for Web of Science ID 000394445700005

• The Role of Focal Adhesion Kinase in Keratinocyte Fibrogenic Gene Expression. International journal of molecular sciences Januszyk, M. n., Kwon, S. H., Wong, V. W., Padmanabhan, J. n., Maan, Z. N., Whittam, A. J., Major, M. R., Gurtner, G. C. 2017; 18 (9)

  Abstract

  Abnormal skin scarring causes functional impairment, psychological stress, and high socioeconomic cost. Evidence shows that altered mechanotransduction pathways have been linked to both inflammation and fibrosis, and that focal adhesion kinase (FAK) is a key mediator of these processes. We investigated the importance of keratinocyte FAK at the single cell level in key fibrogenic pathways critical for scar formation. Keratinocytes were isolated from wildtype and keratinocyte-specific FAK-deleted mice, cultured, and sorted into single cells. Keratinocytes were evaluated using a microfluidic-based platform for high-resolution transcriptional analysis. Partitive clustering, gene enrichment analysis, and network modeling were applied to characterize the significance of FAK on regulating keratinocyte subpopulations and fibrogenic pathways important for scar formation. Considerable transcriptional heterogeneity was observed within the keratinocyte populations. FAK-deleted keratinocytes demonstrated increased expression of genes integral to mechanotransduction and extracellular matrix production, including Igtbl, Mmpla, and Col4a1. Transcriptional activities upon FAK deletion were not identical across all single keratinocytes, resulting in higher frequency of a minor subpopulation characterized by a matrix-remodeling profile compared to wildtype keratinocyte population. The importance of keratinocyte FAK signaling gene expression was revealed. A minor subpopulation of keratinocytes characterized by a matrix-modulating profile may be a keratinocyte subset important for mechanotransduction and scar formation.

  View details for PubMedID 28880199

  View details for PubMedCentralID PMC5618564

• Delivery of monocyte lineage cells in a biomimetic scaffold enhances tissue repair. JCI insight Hu, M. S., Walmsley, G. G., Barnes, L. A., Weiskopf, K. n., Rennert, R. C., Duscher, D. n., Januszyk, M. n., Maan, Z. N., Hong, W. X., Cheung, A. T., Leavitt, T. n., Marshall, C. D., Ransom, R. C., Malhotra, S. n., Moore, A. L., Rajadas, J. n., Lorenz, H. P., Weissman, I. L., Gurtner, G. C., Longaker, M. T. 2017; 2 (19)

  Abstract

  The monocyte lineage is essential to normal wound healing. Macrophage inhibition or knockout in mice results in impaired wound healing through reduced neovascularization, granulation tissue formation, and reepithelialization. Numerous studies have either depleted macrophages or reduced their activity in the context of wound healing. Here, we demonstrate that by increasing the number of macrophages or monocytes in the wound site above physiologic levels via pullulan-collagen composite dermal hydrogel scaffold delivery, the rate of wound healing can be significantly accelerated in both wild-type and diabetic mice, with no adverse effect on the quality of repair. Macrophages transplanted onto wounds differentiate into M1 and M2 phenotypes of different proportions at various time points, ultimately increasing angiogenesis. Given that monocytes can be readily isolated from peripheral blood without in vitro manipulation, these findings hold promise for translational medicine aimed at accelerating wound healing across a broad spectrum of diseases.

  View details for PubMedID 28978794

• Systematic Reviews in Craniofacial Trauma-Strengths and Weaknesses. Annals of plastic surgery Hunter, C., Januszyk, M., Wan, D. C., Momeni, A. 2016; 77 (3): 363-368

  Abstract

  Despite substantial advances in the management of craniofacial trauma, numerous clinical questions remain. These are increasingly being answered using systematic reviews (SRs). However, caution is warranted as their validity and role in influencing clinical practice has been called into question.A PubMed search was performed in October 2014 to identify SRs published up to and including September 2014 in 35 scientific journals. Two authors independently reviewed the literature and extracted data from included studies. Discrepancies were resolved by consensus. Assessment of multiple systematic reviews (AMSTAR) was used to determine the quality of SRs.The initial search retrieved 3080 articles of which 3051 articles were excluded after screening title and abstract. After full-text review of the remaining 29 articles, 3 additional articles were excluded, thus, leaving 26 SRs for final analysis. Regression analysis demonstrated that the overall number of published SRs increased significantly throughout the period analyzed (P = 0.022). The median AMSTAR score of all SRs was 4.5, consistent with a "poor-to-fair" quality. The interobserver agreement was high, as evidenced by a mean κ of 0.91. Although there appeared to be a trend toward an increase in AMSTAR score by year over the period analyzed, this failed to reach statistical significance in terms of median (P = 0.36) or absolute (P = 0.26) counts.A tremendous opportunity exists for improvements in the quality of SRs focusing on craniofacial trauma. In addition to familiarizing authors with quality criteria for SRs, adoption of strict reporting criteria by scientific journals may result in long-term improvements in the quality of reporting.

  View details for DOI 10.1097/SAP.0000000000000633

  View details for PubMedID 26418794

• Microfluidic single-cell transcriptional analysis rationally identifies novel surface marker profiles to enhance cell-based therapies NATURE COMMUNICATIONS Rennert, R. C., Januszyk, M., Sorkin, M., Rodrigues, M., Maan, Z. N., Duscher, D., Whittam, A. J., Kosaraju, R., Chung, M. T., Paik, K., Li, A. Y., Findlay, M., Glotzbach, J. P., Butte, A. J., Gurtner, G. C. 2016; 7

  Abstract

  Current progenitor cell therapies have only modest efficacy, which has limited their clinical adoption. This may be the result of a cellular heterogeneity that decreases the number of functional progenitors delivered to diseased tissue, and prevents correction of underlying pathologic cell population disruptions. Here, we develop a high-resolution method of identifying phenotypically distinct progenitor cell subpopulations via single-cell transcriptional analysis and advanced bioinformatics. When combined with high-throughput cell surface marker screening, this approach facilitates the rational selection of surface markers for prospective isolation of cell subpopulations with desired transcriptional profiles. We establish the usefulness of this platform in costly and highly morbid diabetic wounds by identifying a subpopulation of progenitor cells that is dysfunctional in the diabetic state, and normalizes diabetic wound healing rates following allogeneic application. We believe this work presents a logical framework for the development of targeted cell therapies that can be customized to any clinical application.

  View details for DOI 10.1038/ncomms11945

  View details for Web of Science ID 000379085200001

  View details for PubMedID 27324848

• Concomitant Liposuction Reduces Complications of Vertical Medial Thigh Lift in Massive Weight Loss Patients PLASTIC AND RECONSTRUCTIVE SURGERY Schmidt, M., Pollhammer, M. S., Januszyk, M., Duscher, D., Huemer, G. M. 2016; 137 (6): 1748–57

  Abstract

  Medial thigh lift procedures in the massive weight loss population have been associated with significant complication rates. Liposuction-assisted medial thighplasty has recently been introduced as a technical advancement to improve outcomes. To date, no study is available directly comparing the traditional approach and this new technique. Here, the authors evaluate outcomes and complications of both techniques in a retrospective cohort study.Outcomes of 59 patients undergoing vertical medial thighplasty at the authors' institution between 2008 and 2014 were assessed retrospectively. Evaluated parameters include age, sex, body mass indices, method of weight loss, comorbidities, and complications (e.g., seroma, infection, wound dehiscence, hematoma, and surgical revision). Appropriate statistical analysis was performed.There were 29 patients in the excision-only group and 30 patients in the liposuction-assisted group (all women; average age, 41.5 years). The overall complication rate was significantly reduced in the liposuction-assisted group (13 percent versus 59 percent; p < 0.001). The incidence of individual complications such as seroma formation (zero patients versus 10 patients; p < 0.001) and wound infection (one patient versus eight patients; p = 0.01) was significantly less in the liposuction-assisted group. In addition, we observed a significantly shorter hospital stay (6.0 days versus 7.8 days), reduced number of follow-up visits (2.0 versus 4.4), and reduced time to drain removal (1.8 days versus 4.1 days; p < 0.001) in the liposuction-assisted group.Liposuction-assisted medial thighplasty led to a significant reduction of complications and faster recovery in the massive weight loss patient population. As a consequence, the excision-only vertical thigh lift has been completely abandoned in the authors' clinical practice.Therapeutic, III.

  View details for PubMedID 27219231

• Multiple Subsets of Brain Tumor Initiating Cells Coexist in Glioblastoma STEM CELLS Rennert, R. C., Achrol, A. S., Januszyk, M., Kahn, S. A., Liu, T. T., Liu, Y., Sahoo, D., Rodrigues, M., Maan, Z. N., Wong, V. W., Cheshier, S. H., Chang, S. D., Steinberg, G. K., Harsh, G. R., Gurtner, G. C. 2016; 34 (6): 1702-1707

  Abstract

  Brain tumor-initiating cells (BTICs) are self-renewing multipotent cells critical for tumor maintenance and growth. Using single-cell microfluidic profiling, we identified multiple subpopulations of BTICs co-existing in human glioblastoma, characterized by distinct surface marker expression and single-cell molecular profiles relating to distinct bulk tissue molecular subtypes. These data suggest BTIC subpopulation heterogeneity as an underlying source of intra-tumoral bulk tissue molecular heterogeneity, and will support future studies into BTIC subpopulation-specific therapies. This article is protected by copyright. All rights reserved.

  View details for DOI 10.1002/stem.2359

  View details for Web of Science ID 000378089500025

  View details for PubMedID 26991945

• Microsurgical ear replantation is venous repair necessary? A systematic review MICROSURGERY Momeni, A., Liu, X., Januszyk, M., Wan, D. C., Buncke, G. M., Buntic, R. F., Parrett, B. M. 2016; 36 (4): 345-350

  Abstract

  A common postoperative observation after microsurgical ear replantation has been venous congestion necessitating alternate modes of decongestion, frequently in conjunction with blood transfusion. A comprehensive literature search was performed to assess the relationship between mode of vascular reconstruction and postoperative outcome as well as postoperative transfusion requirement after microsurgical ear replantation.The search was limited to cases of microsurgical ear replantation following complete amputation. Only articles published in English and indexed in PubMed were included.The initial search retrieved 285 articles, which was narrowed down to 40 articles reporting on 60 cases that matched the aforementioned criteria. Reconstruction of the arterial and venous limb (Group 1) was performed in 63.3% of patients and artery-only anastomosis (Group 2) was performed in 31.7%. Among measurable outcomes, only the duration of surgery was significantly different between groups (2.6 hours longer in Group 1 than Group 2; P = 0.0042).In light of contemporary data demonstrating successful artery-only ear replantation, replantation should not be abandoned when unable to establish venous outflow microsurgically. © 2015 Wiley Periodicals, Inc. Microsurgery 36:345-350, 2016.

  View details for DOI 10.1002/micr.22411

  View details for Web of Science ID 000377114900013

  View details for PubMedID 25847853

• High-Resolution Microfluidic Single-Cell Transcriptional Profiling Reveals Clinically Relevant Subtypes among Human Stem Cell Populations Commonly Utilized in Cell-Based Therapies FRONTIERS IN NEUROLOGY Rennert, R. C., Schaefer, R., Bliss, T., Januszyk, M., Sorkin, M., Achrol, A. S., Rodrigues, M., Maan, Z. N., Kluba, T., Steinberg, G. K., Gurtner, G. C. 2016; 7

  Abstract

  Stem cell therapies can promote neural repair and regeneration, yet controversy regarding optimal cell source and mechanism of action has slowed clinical translation, potentially due to undefined cellular heterogeneity. Single-cell resolution is needed to identify clinically relevant subpopulations with the highest therapeutic relevance. We combine single-cell microfluidic analysis with advanced computational modeling to study for the first time two common sources for cell-based therapies, human NSCs and MSCs. This methodology has the potential to logically inform cell source decisions for any clinical application.

  View details for DOI 10.3389/fneur.2016.00041

  View details for Web of Science ID 000372534400001

  View details for PubMedCentralID PMC4801858

• Extracellular superoxide dismutase deficiency impairs wound healing in advanced age by reducing neovascularization and fibroblast function EXPERIMENTAL DERMATOLOGY Fujiwara, T., Duscher, D., Rustad, K. C., Kosaraju, R., Rodrigues, M., Whittam, A. J., Januszyk, M., Maan, Z. N., Gurtner, G. C. 2016; 25 (3): 206-211

  Abstract

  Advanced age is characterized by impairments in wound healing, and evidence is accumulating that this may be due in part to a concomitant increase in oxidative stress. Extended exposure to reactive oxygen species (ROS) is thought to lead to cellular dysfunction and organismal death via the destructive oxidation of intra-cellular proteins, lipids and nucleic acids. Extracellular superoxide dismutase (ecSOD/SOD3) is a prime antioxidant enzyme in the extracellular space that eliminates ROS. Here, we demonstrate that reduced SOD3 levels contribute to healing impairments in aged mice. These impairments include delayed wound closure, reduced neovascularization, impaired fibroblast proliferation and increased neutrophil recruitment. We further establish that SOD3 KO and aged fibroblasts both display reduced production of TGF-β1, leading to decreased differentiation of fibroblasts into myofibroblasts. Taken together, these results suggest that wound healing impairments in ageing are associated with increased levels of ROS, decreased SOD3 expression and impaired extracellular oxidative stress regulation. Our results identify SOD3 as a possible target to correct age-related cellular dysfunction in wound healing.

  View details for DOI 10.1111/exd.12909

  View details for Web of Science ID 000373072800285

• Extracellular superoxide dismutase deficiency impairs wound healing in advanced age by reducing neovascularization and fibroblast function. Experimental dermatology Fujiwara, T., Duscher, D., Rustad, K. C., Kosaraju, R., Rodrigues, M., Whittam, A. J., Januszyk, M., Maan, Z. N., Gurtner, G. C. 2016; 25 (3): 206-211

  Abstract

  Advanced age is characterized by impairments in wound healing, and evidence is accumulating that this may be due in part to a concomitant increase in oxidative stress. Extended exposure to reactive oxygen species (ROS) is thought to lead to cellular dysfunction and organismal death via the destructive oxidation of intra-cellular proteins, lipids and nucleic acids. Extracellular superoxide dismutase (ecSOD/SOD3) is a prime antioxidant enzyme in the extracellular space that eliminates ROS. Here, we demonstrate that reduced SOD3 levels contribute to healing impairments in aged mice. These impairments include delayed wound closure, reduced neovascularization, impaired fibroblast proliferation and increased neutrophil recruitment. We further establish that SOD3 KO and aged fibroblasts both display reduced production of TGF-β1, leading to decreased differentiation of fibroblasts into myofibroblasts. Taken together, these results suggest that wound healing impairments in ageing are associated with increased levels of ROS, decreased SOD3 expression and impaired extracellular oxidative stress regulation. Our results identify SOD3 as a possible target to correct age-related cellular dysfunction in wound healing.

  View details for DOI 10.1111/exd.12909

  View details for PubMedID 26663425

• Adipose-Derived Stem Cell-Seeded Hydrogels Increase Endogenous Progenitor Cell Recruitment and Neovascularization in Wounds TISSUE ENGINEERING PART A Kosaraju, R., Rennert, R. C., Maan, Z. N., Duscher, D., Barrera, J., Whittam, A. J., Januszyk, M., Rajadas, J., Rodrigues, M., Gurtner, G. C. 2016; 22 (3-4): 295-305

  Abstract

  Adipose-derived mesenchymal stem cells (ASCs) are appealing for cell-based wound therapies because of their accessibility and ease of harvest, but their utility is limited by poor cell survival within the harsh wound microenvironment. In prior work, our laboratory has demonstrated that seeding ASCs within a soft pullulan-collagen hydrogel enhances ASC survival and improves wound healing. To more fully understand the mechanism of this therapy, we examined whether ASC-seeded hydrogels were able to modulate the recruitment and/or functionality of endogenous progenitor cells. Employing a parabiosis model and fluorescence-activated cell sorting analysis, we demonstrate that application of ASC-seeded hydrogels to wounds, when compared with injected ASCs or a noncell control, increased the recruitment of provascular circulating bone marrow-derived mesenchymal progenitor cells (BM-MPCs). BM-MPCs comprised 23.0% of recruited circulating progenitor cells in wounds treated with ASC-seeded hydrogels versus 8.4% and 2.1% in those treated with controls, p < 0.05. Exploring the potential for functional modulation of BM-MPCs, we demonstrate a statistically significant increase in BM-MPC migration, proliferation, and tubulization when exposed to hydrogel-seeded ASC-conditioned medium versus control ASC-conditioned medium (73.8% vs. 51.4% scratch assay closure; 9.1% vs. 1.4% proliferation rate; 10.2 vs. 5.5 tubules/HPF; p < 0.05 for all assays). BM-MPC expression of genes related to cell stemness and angiogenesis was also significantly increased following exposure to hydrogel-seeded ASC-conditioned medium (p < 0.05). These data suggest that ASC-seeded hydrogels improve both progenitor cell recruitment and functionality to effect greater neovascularization.

  View details for DOI 10.1089/ten.tea.2015.0277

  View details for Web of Science ID 000369987900012

  View details for PubMedID 26871860

  View details for PubMedCentralID PMC4779321

• Challenges and Opportunities in Drug Delivery for Wound Healing. Advances in wound care Whittam, A. J., Maan, Z. N., Duscher, D., Wong, V. W., Barrera, J. A., Januszyk, M., Gurtner, G. C. 2016; 5 (2): 79-88

  Abstract

  Significance: Chronic wounds remain a significant public health problem. Alterations in normal physiological processes caused by aging or diabetes lead to impaired tissue repair and the development of chronic and nonhealing wounds. Understanding the unique features of the wound environment will be required to develop new therapeutics that impact these disabling conditions. New drug-delivery systems (DDSs) may enhance current and future therapies for this challenging clinical problem. Recent Advances: Historically, physical barriers and biological degradation limited the efficacy of DDSs in wound healing. In aiming at improving and optimizing drug delivery, recent data suggest that combinations of delivery mechanisms, such as hydrogels, small molecules, RNA interference (RNAi), as well as growth factor and stem cell-based therapies (biologics), could offer exciting new opportunities for improving tissue repair. Critical Issues: The lack of effective therapeutic approaches to combat the significant disability associated with chronic wounds has become an area of increasing clinical concern. However, the unique challenges of the wound environment have limited the development of effective therapeutic options for clinical use. Future Directions: New platforms presented in this review may provide clinicians and scientists with an improved understanding of the alternatives for drug delivery in wound care, which may facilitate the development of new therapeutic approaches for patients.

  View details for PubMedID 26862465

• Rapid identification of slow healing wounds. Wound repair and regeneration Jung, K., Covington, S., Sen, C. K., Januszyk, M., Kirsner, R. S., Gurtner, G. C., Shah, N. H. 2016; 24 (1): 181-188

  Abstract

  Chronic nonhealing wounds have a prevalence of 2% in the United States, and cost an estimated $50 billion annually. Accurate stratification of wounds for risk of slow healing may help guide treatment and referral decisions. We have applied modern machine learning methods and feature engineering to develop a predictive model for delayed wound healing that uses information collected during routine care in outpatient wound care centers. Patient and wound data was collected at 68 outpatient wound care centers operated by Healogics Inc. in 26 states between 2009 and 2013. The dataset included basic demographic information on 59,953 patients, as well as both quantitative and categorical information on 180,696 wounds. Wounds were split into training and test sets by randomly assigning patients to training and test sets. Wounds were considered delayed with respect to healing time if they took more than 15 weeks to heal after presentation at a wound care center. Eleven percent of wounds in this dataset met this criterion. Prognostic models were developed on training data available in the first week of care to predict delayed healing wounds. A held out subset of the training set was used for model selection, and the final model was evaluated on the test set to evaluate discriminative power and calibration. The model achieved an area under the curve of 0.842 (95% confidence interval 0.834-0.847) for the delayed healing outcome and a Brier reliability score of 0.00018. Early, accurate prediction of delayed healing wounds can improve patient care by allowing clinicians to increase the aggressiveness of intervention in patients most at risk.

  View details for DOI 10.1111/wrr.12384

  View details for PubMedID 26606167

  View details for PubMedCentralID PMC4820011

• Rapid identification of slow healing wounds WOUND REPAIR AND REGENERATION Jung, K., Covington, S., Sen, C. K., Januszyk, M., Kirsner, R. S., Gurtner, G. C., Shah, N. H. 2016; 24 (1): 181-188

  Abstract

  Chronic nonhealing wounds have a prevalence of 2% in the United States, and cost an estimated $50 billion annually. Accurate stratification of wounds for risk of slow healing may help guide treatment and referral decisions. We have applied modern machine learning methods and feature engineering to develop a predictive model for delayed wound healing that uses information collected during routine care in outpatient wound care centers. Patient and wound data was collected at 68 outpatient wound care centers operated by Healogics Inc. in 26 states between 2009 and 2013. The dataset included basic demographic information on 59,953 patients, as well as both quantitative and categorical information on 180,696 wounds. Wounds were split into training and test sets by randomly assigning patients to training and test sets. Wounds were considered delayed with respect to healing time if they took more than 15 weeks to heal after presentation at a wound care center. Eleven percent of wounds in this dataset met this criterion. Prognostic models were developed on training data available in the first week of care to predict delayed healing wounds. A held out subset of the training set was used for model selection, and the final model was evaluated on the test set to evaluate discriminative power and calibration. The model achieved an area under the curve of 0.842 (95% confidence interval 0.834-0.847) for the delayed healing outcome and a Brier reliability score of 0.00018. Early, accurate prediction of delayed healing wounds can improve patient care by allowing clinicians to increase the aggressiveness of intervention in patients most at risk.

  View details for DOI 10.1111/wrr.12384

  View details for Web of Science ID 000372925500018

  View details for PubMedCentralID PMC4820011

• High-Resolution Microfluidic Single-Cell Transcriptional Profiling Reveals Clinically Relevant Subtypes among Human Stem Cell Populations Commonly Utilized in Cell-Based Therapies. Frontiers in neurology Rennert, R. C., Schäfer, R., Bliss, T., Januszyk, M., Sorkin, M., Achrol, A. S., Rodrigues, M., Maan, Z. N., Kluba, T., Steinberg, G. K., Gurtner, G. C. 2016; 7: 41-?

  Abstract

  Stem cell therapies can promote neural repair and regeneration, yet controversy regarding optimal cell source and mechanism of action has slowed clinical translation, potentially due to undefined cellular heterogeneity. Single-cell resolution is needed to identify clinically relevant subpopulations with the highest therapeutic relevance. We combine single-cell microfluidic analysis with advanced computational modeling to study for the first time two common sources for cell-based therapies, human NSCs and MSCs. This methodology has the potential to logically inform cell source decisions for any clinical application.

  View details for DOI 10.3389/fneur.2016.00041

  View details for PubMedID 27047447

• Stem Cells in Wound Healing: The Future of Regenerative Medicine? A Mini-Review. Gerontology Duscher, D., Barrera, J., Wong, V. W., Maan, Z. N., Whittam, A. J., Januszyk, M., Gurtner, G. C. 2016; 62 (2): 216-225

  Abstract

  The increased risk of disease and decreased capacity to respond to tissue insult in the setting of aging results from complex changes in homeostatic mechanisms, including the regulation of oxidative stress and cellular heterogeneity. In aged skin, the healing capacity is markedly diminished resulting in a high risk for chronic wounds. Stem cell-based therapies have the potential to enhance cutaneous regeneration, largely through trophic and paracrine activity. Candidate cell populations for therapeutic application include adult mesenchymal stem cells, embryonic stem cells and induced pluripotent stem cells. Autologous cell-based approaches are ideal to minimize immune rejection but may be limited by the declining cellular function associated with aging. One strategy to overcome age-related impairments in various stem cell populations is to identify and enrich with functionally superior stem cell subsets via single cell transcriptomics. Another approach is to optimize cell delivery to the harsh environment of aged wounds via scaffold-based cell applications to enhance engraftment and paracrine activity of therapeutic stem cells. In this review, we shed light on challenges and recent advances surrounding stem cell therapies for wound healing and discuss limitations for their clinical adoption.

  View details for DOI 10.1159/000381877

  View details for PubMedID 26045256

• Fibroblast-Specific Deletion of Hypoxia Inducible Factor-1 Critically Impairs Murine Cutaneous Neovascularization and Wound Healing PLASTIC AND RECONSTRUCTIVE SURGERY Duscher, D., Maan, Z. N., Whittam, A. J., Sorkin, M., Hu, M. S., Walmsley, G. G., Baker, H., Fischer, L. H., Januszyk, M., Wong, V. W., Gurtner, G. C. 2015; 136 (5): 1004-1013

  Abstract

  Diabetes and aging are known risk factors for impaired neovascularization in response to ischemic insult, resulting in chronic wounds, and poor outcomes following myocardial infarction and cerebrovascular injury. Hypoxia-inducible factor (HIF)-1α, has been identified as a critical regulator of the response to ischemic injury and is dysfunctional in diabetic and elderly patients. To better understand the role of this master hypoxia regulator within cutaneous tissue, the authors generated and evaluated a fibroblast-specific HIF-1α knockout mouse model.The authors generated floxed HIF-1 mice (HIF-1) by introducing loxP sites around exon 1 of the HIF-1 allele in C57BL/6J mice. Fibroblast-restricted HIF-1α knockout (FbKO) mice were generated by breeding our HIF-1 with tamoxifen-inducible Col1a2-Cre mice (Col1a2-CreER). HIF-1α knockout was evaluated on a DNA, RNA, and protein level. Knockout and wild-type mice were subjected to ischemic flap and wound healing models, and CD31 immunohistochemistry was performed to assess vascularity of healed wounds.Quantitative real-time polymerase chain reaction of FbKO skin demonstrated significantly reduced Hif1 and Vegfa expression compared with wild-type. This finding was confirmed at the protein level (p < 0.05). HIF-1α knockout mice showed significantly impaired revascularization of ischemic tissue and wound closure and vascularity (p < 0.05).Loss of HIF-1α from fibroblasts results in delayed wound healing, reduced wound vascularity, and significant impairment in the ischemic neovascular response. These findings provide new insight into the importance of cell-specific responses to hypoxia during cutaneous neovascularization.

  View details for Web of Science ID 000364092800001

  View details for PubMedID 26505703

• Impairment in Fracture Healing in a Mouse Model of Type 2 Diabetes Is Driven by Skeletal Stem Cell Niche Dysregulation Tevlin, R., Seo, E., Mc Ardle, A., Tong, X., Januszyk, M., Yang, F., Gurtner, G. C., Chan, C. F., Weissman, I. L., Longaker, M. T. ELSEVIER SCIENCE INC. 2015: S115

  View details for DOI 10.1016/j.jamcollsurg.2015.07.268

  View details for Web of Science ID 000361119700230

• Delivery of Macrophages in a Biomimetic Scaffold Accelerates Diabetic Wound Healing Through Enhanced Angiogenesis Walmsley, G. G., Hu, M. S., Duscher, D., Januszyk, M., Maan, Z. N., Senarath-Yapa, K., Tevlin, R., Zielins, E. R., Gurtner, G. C., Longaker, M. T. ELSEVIER SCIENCE INC. 2015: S113–S114

  View details for DOI 10.1016/j.jamcollsurg.2015.07.264

  View details for Web of Science ID 000361119700227

• Microfluidic single cell transcriptional analysis reveals subpopulations of adipose derived stromal cells with enhanced angiogenic potential Zielins, E. R., Januszyk, M., Luan, A., Brett, E. A., Paik, K., Walmsley, G. G., Gurtner, G. C., Longaker, M. T., Wan, D. C. ELSEVIER SCIENCE INC. 2015: E26

  View details for DOI 10.1016/j.jamcollsurg.2015.08.366

  View details for Web of Science ID 000386899000059

• Melanoma Progression Depends on CXCL12 Expression by Host Endothelium Maan, Z. N., Hu, M. S., Whittam, A., Fischer, L. H., Duscher, D., Walmsley, G. G., Januszyk, M., Whitmore, A. J., Longaker, M. T., Gurtner, G. C. ELSEVIER SCIENCE INC. 2015: S116

  View details for DOI 10.1016/j.jamcollsurg.2015.07.272

  View details for Web of Science ID 000361119700234

• Using the wisdom of the crowds to find critical errors in biomedical ontologies: a study of SNOMED CT. Journal of the American Medical Informatics Association Mortensen, J. M., Minty, E. P., Januszyk, M., Sweeney, T. E., Rector, A. L., Noy, N. F., Musen, M. A. 2015; 22 (3): 640-648

  Abstract

  The verification of biomedical ontologies is an arduous process that typically involves peer review by subject-matter experts. This work evaluated the ability of crowdsourcing methods to detect errors in SNOMED CT (Systematized Nomenclature of Medicine Clinical Terms) and to address the challenges of scalable ontology verification.We developed a methodology to crowdsource ontology verification that uses micro-tasking combined with a Bayesian classifier. We then conducted a prospective study in which both the crowd and domain experts verified a subset of SNOMED CT comprising 200 taxonomic relationships.The crowd identified errors as well as any single expert at about one-quarter of the cost. The inter-rater agreement (κ) between the crowd and the experts was 0.58; the inter-rater agreement between experts themselves was 0.59, suggesting that the crowd is nearly indistinguishable from any one expert. Furthermore, the crowd identified 39 previously undiscovered, critical errors in SNOMED CT (eg, 'septic shock is a soft-tissue infection').The results show that the crowd can indeed identify errors in SNOMED CT that experts also find, and the results suggest that our method will likely perform well on similar ontologies. The crowd may be particularly useful in situations where an expert is unavailable, budget is limited, or an ontology is too large for manual error checking. Finally, our results suggest that the online anonymous crowd could successfully complete other domain-specific tasks.We have demonstrated that the crowd can address the challenges of scalable ontology verification, completing not only intuitive, common-sense tasks, but also expert-level, knowledge-intensive tasks.

  View details for DOI 10.1136/amiajnl-2014-002901

  View details for PubMedID 25342179

• Skin fibrosis. Identification and isolation of a dermal lineage with intrinsic fibrogenic potential. Science Rinkevich, Y., Walmsley, G. G., Hu, M. S., Maan, Z. N., Newman, A. M., Drukker, M., Januszyk, M., Krampitz, G. W., Gurtner, G. C., Lorenz, H. P., Weissman, I. L., Longaker, M. T. 2015; 348 (6232)

  Abstract

  Dermal fibroblasts represent a heterogeneous population of cells with diverse features that remain largely undefined. We reveal the presence of at least two fibroblast lineages in murine dorsal skin. Lineage tracing and transplantation assays demonstrate that a single fibroblast lineage is responsible for the bulk of connective tissue deposition during embryonic development, cutaneous wound healing, radiation fibrosis, and cancer stroma formation. Lineage-specific cell ablation leads to diminished connective tissue deposition in wounds and reduces melanoma growth. Using flow cytometry, we identify CD26/DPP4 as a surface marker that allows isolation of this lineage. Small molecule-based inhibition of CD26/DPP4 enzymatic activity during wound healing results in diminished cutaneous scarring. Identification and isolation of these lineages hold promise for translational medicine aimed at in vivo modulation of fibrogenic behavior.

  View details for DOI 10.1126/science.aaa2151

  View details for PubMedID 25883361

  View details for PubMedCentralID PMC5088503

• Identification and isolation of a dermal lineage with intrinsic fibrogenic potential SCIENCE Rinkevich, Y., Walmsley, G. G., Hu, M. S., Maan, Z. N., Newman, A. M., Drukker, M., Januszyk, M., Krampitz, G. W., Gurtner, G. C., Lorenz, H. P., Weissman, I. L., Longaker, M. T. 2015; 348 (6232): 302-?

  Abstract

  Dermal fibroblasts represent a heterogeneous population of cells with diverse features that remain largely undefined. We reveal the presence of at least two fibroblast lineages in murine dorsal skin. Lineage tracing and transplantation assays demonstrate that a single fibroblast lineage is responsible for the bulk of connective tissue deposition during embryonic development, cutaneous wound healing, radiation fibrosis, and cancer stroma formation. Lineage-specific cell ablation leads to diminished connective tissue deposition in wounds and reduces melanoma growth. Using flow cytometry, we identify CD26/DPP4 as a surface marker that allows isolation of this lineage. Small molecule-based inhibition of CD26/DPP4 enzymatic activity during wound healing results in diminished cutaneous scarring. Identification and isolation of these lineages hold promise for translational medicine aimed at in vivo modulation of fibrogenic behavior.

  View details for DOI 10.1126/science.aaa2151

  View details for Web of Science ID 000352999000034

  View details for PubMedCentralID PMC5088503

• Studies in Fat Grafting: Part IV. Adipose-Derived Stromal Cell Gene Expression in Cell-Assisted Lipotransfer PLASTIC AND RECONSTRUCTIVE SURGERY Garza, R. M., Rennert, R. C., Paik, K. J., Atashroo, D., Chung, M. T., Duscher, D., Januszyk, M., Gurtner, G. C., Longaker, M. T., Wan, D. C. 2015; 135 (4): 1045-1055

  Abstract

  Fat graft volume retention remains highly unpredictable, but addition of adipose-derived stromal cells to fat grafts has been shown to improve retention. The present study aimed to investigate the mechanisms involved in adipose-derived stromal cell enhancement of fat grafting.Adipose-derived stromal cells isolated from human lipoaspirate were labeled with green fluorescent protein and luciferase. Fat grafts enhanced with adipose-derived stromal cells were injected into the scalp and bioluminescent imaging was performed to follow retention of adipose-derived stromal cells within the fat graft. Fat grafts were also explanted at days 1, 5, and 10 after grafting for adipose-derived stromal cell extraction and single-cell gene analysis. Finally, CD31 immunohistochemical staining was performed on fat grafts enriched with adipose-derived stromal cells.Bioluminescent imaging demonstrated significant reduction in luciferase-positive adipose-derived stromal cells within fat grafts at 5 days after grafting. A similar reduction in viable green fluorescent protein-positive adipose-derived stromal cells retrieved from explanted grafts was also noted. Single-cell analysis revealed expression of multiple genes/markers related to cell survival and angiogenesis, including BMPR2, CD90, CD105, FGF2, CD248, TGFß1, and VEGFA. Genes involved in adipogenesis were not expressed by adipose-derived stromal cells. Finally, CD31 staining revealed significantly higher vascular density in fat grafts explanted at day 10 after grafting.Although adipose-derived stromal cell survival in the hypoxic graft environment decreases significantly over time, these cells provide multiple angiogenic growth factors. Therefore, improved fat graft volume retention with adipose-derived stromal cell enrichment may be attributable to improved graft vascularization.

  View details for DOI 10.1097/PRS.0000000000001104

  View details for Web of Science ID 000351910200043

  View details for PubMedID 25502860

  View details for PubMedCentralID PMC4376612

• Cell recruitment by amnion chorion grafts promotes neovascularization JOURNAL OF SURGICAL RESEARCH Maan, Z. N., Rennert, R. C., Koob, T. J., Januszyk, M., Li, W. W., Gurtner, G. C. 2015; 193 (2): 953-962

  Abstract

  Nonhealing wounds are a significant health burden. Stem and progenitor cells can accelerate wound repair and regeneration. Human amniotic membrane has demonstrated efficacy in promoting wound healing, though the underlying mechanisms remain unknown. A dehydrated human amnion chorion membrane (dHACM) was tested for its ability to recruit hematopoietic progenitor cells to a surgically implanted graft in a murine model of cutaneous ischemia.dHACM was subcutaneously implanted under elevated skin (ischemic stimulus) in either wild-type mice or mice surgically parabiosed to green fluorescent protein (GFP) + reporter mice. A control acellular dermal matrix, elevated skin without an implant, and normal unwounded skin were used as controls. Wound tissue was harvested and processed for histology and flow cytometric analysis.Implanted dHACMs recruited significantly more progenitor cells compared with controls (*P < 0.05) and displayed in vivo SDF-1 expression with incorporation of CD34 + progenitor cells within the matrix. Parabiosis modeling confirmed the circulatory origin of recruited cells, which coexpressed progenitor cell markers and were localized to foci of neovascularization within implanted matrices.In summary, dHACM effectively recruits circulating progenitor cells, likely because of stromal derived factor 1 (SDF-1) expression. The recruited cells express markers of "stemness" and localize to sites of neovascularization, providing a partial mechanism for the clinical efficacy of human amniotic membrane in the treatment of chronic wounds.

  View details for DOI 10.1016/j.jss.2014.08.045

  View details for Web of Science ID 000346244300056

  View details for PubMedID 25266600

• Exercise induces stromal cell-derived factor-1a-mediated release of endothelial progenitor cells with increased vasculogenic function. Plastic and reconstructive surgery Chang, E., Paterno, J., Duscher, D., Maan, Z. N., Chen, J. S., Januszyk, M., Rodrigues, M., Rennert, R. C., Bishop, S., Whitmore, A. J., Whittam, A. J., Longaker, M. T., Gurtner, G. C. 2015; 135 (2): 340e-50e

  Abstract

  Endothelial progenitor cells have been shown to traffic to and incorporate into ischemic tissues, where they participate in new blood vessel formation, a process termed vasculogenesis. Previous investigation has demonstrated that endothelial progenitor cells appear to mobilize from bone marrow to the peripheral circulation after exercise. In this study, the authors investigate potential etiologic factors driving this mobilization and investigate whether the mobilized endothelial progenitor cells are the same as those present at baseline.Healthy volunteers (n = 5) performed a monitored 30-minute run to maintain a heart rate greater than 140 beats/min. Venous blood samples were collected before, 10 minutes after, and 24 hours after exercise. Endothelial progenitor cells were isolated and evaluated.Plasma levels of stromal cell-derived factor-1α significantly increased nearly two-fold immediately after exercise, with a nearly four-fold increase in circulating endothelial progenitor cells 24 hours later. The endothelial progenitor cells isolated following exercise demonstrated increased colony formation, proliferation, differentiation, and secretion of angiogenic cytokines. Postexercise endothelial progenitor cells also exhibited a more robust response to hypoxic stimulation.Exercise appears to mobilize endothelial progenitor cells and augment their function by means of stromal cell-derived factor 1α-dependent signaling. The population of endothelial progenitor cells mobilized following exercise is primed for vasculogenesis with increased capacity for proliferation, differentiation, secretion of cytokines, and responsiveness to hypoxia. Given the evidence demonstrating positive regenerative effects of exercise, this may be one possible mechanism for its benefits.

  View details for DOI 10.1097/PRS.0000000000000917

  View details for PubMedID 25626819

• Transdermal deferoxamine prevents pressure-induced diabetic ulcers. Proceedings of the National Academy of Sciences of the United States of America Duscher, D., Neofytou, E., Wong, V. W., Maan, Z. N., Rennert, R. C., Inayathullah, M., Januszyk, M., Rodrigues, M., Malkovskiy, A. V., Whitmore, A. J., Walmsley, G. G., Galvez, M. G., Whittam, A. J., Brownlee, M., Rajadas, J., Gurtner, G. C. 2015; 112 (1): 94-99

  Abstract

  There is a high mortality in patients with diabetes and severe pressure ulcers. For example, chronic pressure sores of the heels often lead to limb loss in diabetic patients. A major factor underlying this is reduced neovascularization caused by impaired activity of the transcription factor hypoxia inducible factor-1 alpha (HIF-1α). In diabetes, HIF-1α function is compromised by a high glucose-induced and reactive oxygen species-mediated modification of its coactivator p300, leading to impaired HIF-1α transactivation. We examined whether local enhancement of HIF-1α activity would improve diabetic wound healing and minimize the severity of diabetic ulcers. To improve HIF-1α activity we designed a transdermal drug delivery system (TDDS) containing the FDA-approved small molecule deferoxamine (DFO), an iron chelator that increases HIF-1α transactivation in diabetes by preventing iron-catalyzed reactive oxygen stress. Applying this TDDS to a pressure-induced ulcer model in diabetic mice, we found that transdermal delivery of DFO significantly improved wound healing. Unexpectedly, prophylactic application of this transdermal delivery system also prevented diabetic ulcer formation. DFO-treated wounds demonstrated increased collagen density, improved neovascularization, and reduction of free radical formation, leading to decreased cell death. These findings suggest that transdermal delivery of DFO provides a targeted means to both prevent ulcer formation and accelerate diabetic wound healing with the potential for rapid clinical translation.

  View details for DOI 10.1073/pnas.1413445112

  View details for PubMedID 25535360

• Evaluating the Effect of Cell Culture on Gene Expression in Primary Tissue Samples Using Microfluidic-Based Single Cell Transcriptional Analysis. Microarrays (Basel, Switzerland) Januszyk, M., Rennert, R. C., Sorkin, M., Maan, Z. N., Wong, L. K., Whittam, A. J., Whitmore, A., Duscher, D., Gurtner, G. C. 2015; 4 (4): 540-550

  Abstract

  Significant transcriptional heterogeneity is an inherent property of complex tissues such as tumors and healing wounds. Traditional methods of high-throughput analysis rely on pooling gene expression data from hundreds of thousands of cells and reporting a population-wide average that is unable to capture differences within distinct cell subsets. Recent advances in microfluidic technology have permitted the development of large-scale single cell analytic methods that overcome this limitation. The increased granularity afforded by such approaches allows us to answer the critical question of whether expansion in cell culture significantly alters the transcriptional characteristics of cells isolated from primary tissue. Here we examine an established population of human adipose-derived stem cells (ASCs) using a novel, microfluidic-based method for high-throughput transcriptional interrogation, coupled with advanced bioinformatic analysis, to evaluate the dynamics of single cell gene expression among primary, passage 0, and passage 1 stem cells. We find significant differences in the transcriptional profiles of cells from each group, as well as a considerable shift in subpopulation dynamics as those subgroups better able to adhere and proliferate under these culture conditions gradually emerge as dominant. Taken together, these findings reinforce the importance of using primary or very early passage cells in future studies.

  View details for DOI 10.3390/microarrays4040540

  View details for PubMedID 27600239

  View details for PubMedCentralID PMC4996408

• Reduced Regenerative Capacity of Aged Adipose Derived Stem Cells is Caused by Alterations of Cell Subpopulation Dynamics Duscher, D., Rennert, R. C., Januszyk, M., Maan, Z. N., Whittam, A. J., Hu, M. S., Walmsley, G. G., Atashroo, D., Longaker, M. T., Gurtner, G. C. ELSEVIER SCIENCE INC. 2014: S136

  View details for DOI 10.1016/j.jamcollsurg.2014.07.326

  View details for Web of Science ID 000342420900287

• Understanding regulatory pathways of neovascularization in diabetes. Expert review of endocrinology & metabolism Maan, Z. N., Rodrigues, M., Rennert, R. C., Whitmore, A., Duscher, D., Januszyk, M., Hu, M., Whittam, A. J., Davis, C. R., Gurtner, G. C. 2014; 9 (5): 487-501

  Abstract

  Diabetes mellitus and its associated comorbidities represent a significant health burden worldwide. Vascular dysfunction is the major contributory factor in the development of these comorbidities, which include impaired wound healing, cardiovascular disease and proliferative diabetic retinopathy. While the etiology of abnormal neovascularization in diabetes is complex and paradoxical, the dysregulation of the varied processes contributing to the vascular response are due in large part to the effects of hyperglycemia. In this review, we explore the mechanisms by which hyperglycemia disrupts chemokine expression and function, including the critical hypoxia inducible factor-1 axis. We place particular emphasis on the therapeutic potential of strategies addressing these pathways; as such targeted approaches may one day help alleviate the healthcare burden of diabetic sequelae.

  View details for DOI 10.1586/17446651.2014.938054

  View details for PubMedID 30736211

• Noncontact, low-frequency ultrasound therapy enhances neovascularization and wound healing in diabetic mice. Plastic and reconstructive surgery Maan, Z. N., Januszyk, M., Rennert, R. C., Duscher, D., Rodrigues, M., Fujiwara, T., Ho, N., Whitmore, A., Hu, M. S., Longaker, M. T., Gurtner, G. C. 2014; 134 (3): 402e-11e

  Abstract

  Chronic wounds are a major source of morbidity for patients and represent a significant health burden. Implementing noninvasive techniques that accelerate healing of these wounds would provide great benefit. Ultrasound appears to be an effective modality for the treatment of chronic wounds in humans. MIST Therapy is a noncontact, low-frequency ultrasound treatment delivered through a saline mist. A variety of mechanisms have been proposed to explain the efficacy of ultrasound therapy, but the underlying molecular and cellular pathways impacted by this technique remain unclear. The in vivo effect of noncontact, low-frequency ultrasound was therefore examined in a humanized excisional wound model.The treatment group received noncontact, low-frequency ultrasound therapy three times per week, whereas the control group received a standard dressing change. Wounds were photographed at regular intervals to calculate healing kinetics. Wound tissue was harvested and processed for histology, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay.The MIST group demonstrated significantly accelerated wound healing, with 17.3 days to wound closure compared with 24 days in the controls (p < 0.05). This improvement became evident by day 9, with healing evidenced by significantly decreased mean wound area relative to original size (68 percent versus 80 percent; p < 0.01). Expression of markers of neovascularization (stromal cell-derived factor 1, vascular endothelial growth factor, and CD31) was also increased in the wound beds of noncontact, low-frequency ultrasound-treated mice compared with controls.Noncontact, low-frequency ultrasound treatment improves neovascularization and wound closure rates in excisional wounds for diabetic mice, likely because of the stimulated release of angiogenic factors.

  View details for DOI 10.1097/PRS.0000000000000467

  View details for PubMedID 25158717

• A Randomized Controlled Trial of the embrace Advanced Scar Therapy Device to Reduce Incisional Scar Formation. Plastic and reconstructive surgery Longaker, M. T., Rohrich, R. J., Greenberg, L., Furnas, H., Wald, R., Bansal, V., Seify, H., Tran, A., Weston, J., Korman, J. M., Chan, R., Kaufman, D., Dev, V. R., Mele, J. A., Januszyk, M., Cowley, C., McLaughlin, P., Beasley, B., Gurtner, G. C. 2014; 134 (3): 536-546

  Abstract

  Scarring represents a significant biomedical burden in clinical medicine. Mechanomodulation has been linked to scarring through inflammation, but until now a systematic approach to attenuate mechanical force and reduce scarring has not been possible.The authors conducted a 12-month, prospective, open-label, randomized, multicenter clinical trial to evaluate abdominoplasty scar appearance following postoperative treatment with the embrace Advanced Scar Therapy device to reduce mechanical forces on healing surgical incisions. Incisions from 65 healthy adult subjects were randomized to receive embrace treatment on one half of an abdominoplasty incision and control treatment (surgeon's optimal care methods) on the other half. The primary endpoint for this study was the difference between assessments of scar appearance for the treated and control sides using the visual analogue scale scar score.Final 12-month study photographs were obtained from 36 subjects who completed at least 5 weeks of dressing application. The mean visual analogue scale score for embrace-treated scars (2.90) was significantly improved compared with control-treated scars (3.29) at 12 months (difference, 0.39; 95 percent confidence interval, 0.14 to 0.66; p = 0.027). Both subjects and investigators found that embrace-treated scars demonstrated significant improvements in overall appearance at 12 months using the Patient and Observer Scar Assessment Scale evaluation (p = 0.02 and p < 0.001, respectively). No serious adverse events were reported.These results demonstrate that the embrace device significantly reduces scarring following abdominoplasty surgery. To the authors' knowledge, this represents the first level I evidence for postoperative scar reduction.Therapeutic, II.

  View details for DOI 10.1097/PRS.0000000000000417

  View details for PubMedID 24804638

• Diabetes irreversibly depletes bone marrow-derived mesenchymal progenitor cell subpopulations. Diabetes Januszyk, M., Sorkin, M., Glotzbach, J. P., Vial, I. N., Maan, Z. N., Rennert, R. C., Duscher, D., Thangarajah, H., Longaker, M. T., Butte, A. J., Gurtner, G. C. 2014; 63 (9): 3047-3056

  Abstract

  Diabetic vascular pathology is largely attributable to impairments in tissue recovery from hypoxia. Circulating progenitor cells have been postulated to play a role in ischemic recovery and deficiencies in these cells have been well described in diabetic patients. Here, we examine bone marrow-derived mesenchymal progenitor cells (BM-MPCs) that have previously been shown to be important for new blood vessel formation, and demonstrate significant deficits in the context of diabetes. Further, we determine that this dysfunction is attributable to intrinsic defects in diabetic BM-MPCs that are not correctable by restoring glucose homeostasis. We identify two transcriptionally distinct subpopulations that are selectively depleted by both type 1 and type 2 diabetes, and these subpopulations have pro-vasculogenic expression profiles, suggesting that they are vascular progenitor cells. These results suggest that the clinically observed deficits in progenitor cells may be attributable to selective and irreversible depletion of progenitor cell subsets in patients with diabetes.

  View details for DOI 10.2337/db13-1366

  View details for PubMedID 24740572

• Clonal analysis reveals nerve-dependent and independent roles on mammalian hind limb tissue maintenance and regeneration PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Rinkevich, Y., Montoro, D. T., Muhonen, E., Walmsley, G. G., Lo, D., Hasegawa, M., Januszyk, M., Connolly, A. J., Weissman, I. L., Longaker, M. T. 2014; 111 (27): 9846-9851

  Abstract

  The requirement and influence of the peripheral nervous system on tissue replacement in mammalian appendages remain largely undefined. To explore this question, we have performed genetic lineage tracing and clonal analysis of individual cells of mouse hind limb tissues devoid of nerve supply during regeneration of the digit tip, normal maintenance, and cutaneous wound healing. We show that cellular turnover, replacement, and cellular differentiation from presumed tissue stem/progenitor cells within hind limb tissues remain largely intact independent of nerve and nerve-derived factors. However, regenerated digit tips in the absence of nerves displayed patterning defects in bone and nail matrix. These nerve-dependent phenotypes mimic clinical observations of patients with nerve damage resulting from spinal cord injury and are of significant interest for translational medicine aimed at understanding the effects of nerves on etiologies of human injury.

  View details for DOI 10.1073/pnas.1410097111

  View details for Web of Science ID 000338514800040

  View details for PubMedCentralID PMC4103362

• Clonal analysis reveals nerve-dependent and independent roles on mammalian hind limb tissue maintenance and regeneration. Proceedings of the National Academy of Sciences of the United States of America Rinkevich, Y., Montoro, D. T., Muhonen, E., Walmsley, G. G., Lo, D., Hasegawa, M., Januszyk, M., Connolly, A. J., Weissman, I. L., Longaker, M. T. 2014; 111 (27): 9846-9851

  Abstract

  The requirement and influence of the peripheral nervous system on tissue replacement in mammalian appendages remain largely undefined. To explore this question, we have performed genetic lineage tracing and clonal analysis of individual cells of mouse hind limb tissues devoid of nerve supply during regeneration of the digit tip, normal maintenance, and cutaneous wound healing. We show that cellular turnover, replacement, and cellular differentiation from presumed tissue stem/progenitor cells within hind limb tissues remain largely intact independent of nerve and nerve-derived factors. However, regenerated digit tips in the absence of nerves displayed patterning defects in bone and nail matrix. These nerve-dependent phenotypes mimic clinical observations of patients with nerve damage resulting from spinal cord injury and are of significant interest for translational medicine aimed at understanding the effects of nerves on etiologies of human injury.

  View details for DOI 10.1073/pnas.1410097111

  View details for PubMedID 24958860

• Gene expression in fetal murine keratinocytes and fibroblasts JOURNAL OF SURGICAL RESEARCH Hu, M. S., Januszyk, M., Hong, W. X., Walmsley, G. G., Zielins, E. R., Atashroo, D. A., Maan, Z. N., McArdle, A., Takanishi, D. M., Gurtner, G. C., Longaker, M. T., Lorenz, H. P. 2014; 190 (1): 344-357

  Abstract

  Early fetuses heal wounds without the formation of a scar. Many studies have attempted to explain this remarkable phenomenon. However, the exact mechanism remains unknown. Herein, we examine the predominant cell types of the epidermis and dermis-the keratinocyte and fibroblast-during different stages of fetal development to better understand the changes that lead to scarring wound repair versus regeneration.Keratinocytes and fibroblasts were harvested and cultured from the dorsal skin of time-dated BALB/c fetuses. Total RNA was isolated and microarray analysis was performed using chips with 42,000 genes. Significance analysis of microarrays was used to select genes with >2-fold expression differences with a false discovery rate <2. Enrichment analysis was performed on significant genes to identify differentially expressed pathways.By comparing the gene expression profile of keratinocytes from E16 versus E18 fetuses, we identified 24 genes that were downregulated at E16. Analysis of E16 and E18 fibroblasts revealed 522 differentially expressed genes. Enrichment analysis showed the top 20 signaling pathways that were downregulated in E16 keratinocytes and upregulated or downregulated in E16 fibroblasts.Our data reveal 546 differentially expressed genes in keratinocytes and fibroblasts between the scarless and scarring transition. In addition, a total of 60 signaling pathways have been identified to be either upregulated or downregulated in these cell types. The genes and pathways recognized by our study may prove to be essential targets that may discriminate between fetal wound regeneration and adult wound repair.

  View details for DOI 10.1016/j.jss.2014.02.030

  View details for Web of Science ID 000338444700051

• Mechanotransduction and fibrosis JOURNAL OF BIOMECHANICS Duscher, D., Maan, Z. N., Wong, V. W., Rennert, R. C., Januszyk, M., Rodrigues, M., Hu, M., Whitmore, A. J., Whittam, A. J., Longaker, M. T., Gurtner, G. C. 2014; 47 (9): 1997-2005

  Abstract

  Scarring and tissue fibrosis represent a significant source of morbidity in the United States. Despite considerable research focused on elucidating the mechanisms underlying cutaneous scar formation, effective clinical therapies are still in the early stages of development. A thorough understanding of the various signaling pathways involved is essential to formulate strategies to combat fibrosis and scarring. While initial efforts focused primarily on the biochemical mechanisms involved in scar formation, more recent research has revealed a central role for mechanical forces in modulating these pathways. Mechanotransduction, which refers to the mechanisms by which mechanical forces are converted to biochemical stimuli, has been closely linked to inflammation and fibrosis and is believed to play a critical role in scarring. This review provides an overview of our current understanding of the mechanisms underlying scar formation, with an emphasis on the relationship between mechanotransduction pathways and their therapeutic implications.

  View details for DOI 10.1016/j.jbiomech.2014.03.031

  View details for Web of Science ID 000338621900009

• Transcriptional profiling of rapamycin-treated fibroblasts from hypertrophic and keloid scars. Annals of plastic surgery Wong, V. W., You, F., Januszyk, M., Gurtner, G. C., Kuang, A. A. 2014; 72 (6): 711-719

  Abstract

  Excess scar formation after cutaneous injury can result in hypertrophic scar (HTS) or keloid formation. Modern strategies to treat pathologic scarring represent nontargeted approaches that produce suboptimal results. Mammalian target of rapamycin (mTOR), a central mediator of inflammation, has been proposed as a novel target to block fibroproliferation. To examine its mechanism of action, we performed genomewide microarray on human fibroblasts (from normal skin, HTS, and keloid scars) treated with the mTOR inhibitor, rapamycin. Hypertrophic scar and keloid fibroblasts demonstrated overexpression of collagen I and III that was effectively abrogated with rapamycin. Blockade of mTOR specifically impaired fibroblast expression of the collagen biosynthesis genes PLOD, PCOLCE, and P4HA, targets significantly overexpressed in HTS and keloid scars. These data suggest that pathologic scarring can be abrogated via modulation of mTOR pathways in procollagen and collagen processing.

  View details for DOI 10.1097/SAP.0b013e31826956f6

  View details for PubMedID 24835866

• In Vivo clonal analysis reveals lineage-restricted progenitor characteristics in Mammalian kidney development, maintenance, and regeneration. Cell reports Rinkevich, Y., Montoro, D. T., Contreras-Trujillo, H., Harari-Steinberg, O., Newman, A. M., Tsai, J. M., Lim, X., Van-Amerongen, R., Bowman, A., Januszyk, M., Pleniceanu, O., Nusse, R., Longaker, M. T., Weissman, I. L., Dekel, B. 2014; 7 (4): 1270-1283

  Abstract

  The mechanism and magnitude by which the mammalian kidney generates and maintains its proximal tubules, distal tubules, and collecting ducts remain controversial. Here, we use long-term in vivo genetic lineage tracing and clonal analysis of individual cells from kidneys undergoing development, maintenance, and regeneration. We show that the adult mammalian kidney undergoes continuous tubulogenesis via expansions of fate-restricted clones. Kidneys recovering from damage undergo tubulogenesis through expansions of clones with segment-specific borders, and renal spheres developing in vitro from individual cells maintain distinct, segment-specific fates. Analysis of mice derived by transfer of color-marked embryonic stem cells (ESCs) into uncolored blastocysts demonstrates that nephrons are polyclonal, developing from expansions of singly fated clones. Finally, we show that adult renal clones are derived from Wnt-responsive precursors, and their tracing in vivo generates tubules that are segment specific. Collectively, these analyses demonstrate that fate-restricted precursors functioning as unipotent progenitors continuously maintain and self-preserve the mouse kidney throughout life.

  View details for DOI 10.1016/j.celrep.2014.04.018

  View details for PubMedID 24835991

  View details for PubMedCentralID PMC4425291

• Tracking the elusive fibrocyte: identification and characterization of collagen-producing hematopoietic lineage cells during murine wound healing. Stem cells Suga, H., Rennert, R. C., Rodrigues, M., Sorkin, M., Glotzbach, J. P., Januszyk, M., Fujiwara, T., Longaker, M. T., Gurtner, G. C. 2014; 32 (5): 1347-1360

  Abstract

  Fibrocytes are a unique population of circulating cells reported to exhibit characteristics of both hematopoietic and mesenchymal cells, and play an important role in wound healing. However, putative fibrocytes have been found to lose expression of hematopoietic surface markers such as CD45 during differentiation, making it difficult to track these cells in vivo with conventional methodologies. In this study, to distinguish hematopoietic and nonhematopoietic cells without surface markers, we took advantage of the gene vav 1, which is expressed solely on hematopoietic cells but not on other cell types, and established a novel transgenic mouse, in which hematopoietic cells are irreversibly labeled with green fluorescent protein and nonhematopoietic cells with red fluorescent protein. Use of single-cell transcriptional analysis in this mouse model revealed two discrete types of collagen I (Col I) expressing cells of hematopoietic lineage recruited into excisional skin wounds. We confirmed this finding on a protein level, with one subset of these Col I synthesizing cells being CD45+ and CD11b+, consistent with the traditional definition of a fibrocyte, while another was CD45- and Cd11b-, representing a previously unidentified population. Both cell types were found to initially peak, then reduce posthealing, consistent with a disappearance from the wound site and not a loss of identifying surface marker expression. Taken together, we have unambiguously identified two cells of hematopoietic origin that are recruited to the wound site and deposit collagen, definitively confirming the existence and natural time course of fibrocytes in cutaneous healing. Stem Cells 2014;32:1347-1360.

  View details for DOI 10.1002/stem.1648

  View details for PubMedID 24446236

• Mechanical offloading of incisional wounds is associated with transcriptional downregulation of inflammatory pathways in a large animal model ORGANOGENESIS Januszyk, M., Wong, V. W., Bhatt, K. A., Vial, I. N., Paterno, J., Longaker, M. T., Gurtner, G. C. 2014; 10 (2): 186-193

  Abstract

  Cutaneous scarring is a major source of morbidity and current therapies to mitigate scar formation remain ineffective. Although wound fibrosis and inflammation are highly linked, only recently have mechanical forces been implicated in these pathways. Our group has developed a topical polymer device that significantly reduces post-injury scar formation via the manipulation of mechanical forces. Here we extend these studies to examine the genomewide transcriptional effects of mechanomodulation during scar formation using a validated large animal model, the red Duroc pig. We demonstrate that mechanical loading of incisional wounds upregulates expression of genes associated with inflammatory and fibrotic pathways, and that device-mediated offloading of these wounds reverses these effects. Validation studies are needed to clarify the clinical significance of these findings.

  View details for DOI 10.4161/org.28818

  View details for Web of Science ID 000341807300005

  View details for PubMedID 24739276

  View details for PubMedCentralID PMC4154952

• Mechanotransduction and fibrosis. Journal of biomechanics Duscher, D., Maan, Z. N., Wong, V. W., Rennert, R. C., Januszyk, M., Rodrigues, M., Hu, M., Whitmore, A. J., Whittam, A. J., Longaker, M. T., Gurtner, G. C. 2014

  Abstract

  Scarring and tissue fibrosis represent a significant source of morbidity in the United States. Despite considerable research focused on elucidating the mechanisms underlying cutaneous scar formation, effective clinical therapies are still in the early stages of development. A thorough understanding of the various signaling pathways involved is essential to formulate strategies to combat fibrosis and scarring. While initial efforts focused primarily on the biochemical mechanisms involved in scar formation, more recent research has revealed a central role for mechanical forces in modulating these pathways. Mechanotransduction, which refers to the mechanisms by which mechanical forces are converted to biochemical stimuli, has been closely linked to inflammation and fibrosis and is believed to play a critical role in scarring. This review provides an overview of our current understanding of the mechanisms underlying scar formation, with an emphasis on the relationship between mechanotransduction pathways and their therapeutic implications.

  View details for DOI 10.1016/j.jbiomech.2014.03.031

  View details for PubMedID 24709567

• Abstract 15: Characterization of the Endothelial Progenitor Cell from Adult Tissue using Vav/Cre RFP-GFP Murine Model and Single Cell Microfluidics. Plastic and reconstructive surgery Rodrigues, M., Rennert, R. C., Bishop, S., Januszyk, M., Maan, Z., Sorkin, M., Duscher, D., Gurtner, G. C. 2014; 133 (3): 25-?

  View details for DOI 10.1097/01.prs.0000445018.79483.78

  View details for PubMedID 25942126

• Abstract 10: Global and Endothelial Cell Specific Deletion of SDF-1 Results in Delayed Wound Healing. Plastic and reconstructive surgery Maan, Z. N., Ho, N., Rennert, R. C., Duscher, D., Sorkin, M., Rodrigues, M., Chen, J., Vial, I. N., Januszyk, M., Findlay, M., Hu, M., Walmsley, G., Longaker, M. T., Gurtner, G. C. 2014; 133 (3): 20-?

  View details for DOI 10.1097/01.prs.0000444963.66915.ba

  View details for PubMedID 25942121

• Abstract 8: SDF-1 Regulates Adipose Niche Homeostasis and Adipose Derived Stromal Cell Function. Plastic and reconstructive surgery Maan, Z. N., Rennert, R. C., Duscher, D., Januszyk, M., Paik, K., Chung, M. T., Paik, K., Fujiwara, T., Rodrigues, M., Ho, N., Baker, H., Perez, M., Hu, M., Sorkin, M., Longaker, M. T., Gurtner, G. C. 2014; 133 (3): 15-16

  View details for DOI 10.1097/01.prs.0000444941.23852.ce

  View details for PubMedID 25942119

• Abstract 33: Stress Offloading through Mechanomodulation is Associated with Down-Regulation of Inflammatory Pathways in a Large Animal Model. Plastic and reconstructive surgery Januszyk, M., Wong, V. W., Bhatt, K., Vial, I. N., Dauskardt, R., Longaker, M. T., Gurtner, G. C. 2014; 133 (3): 44-?

  View details for DOI 10.1097/01.prs.0000445066.09978.3b

  View details for PubMedID 25942144

• Gene expression in fetal murine keratinocytes and fibroblasts. The Journal of surgical research Hu, M. S., Januszyk, M., Hong, W. X., Walmsley, G. G., Zielins, E. R., Atashroo, D. A., Maan, Z. N., McArdle, A., Takanishi, D. M., Gurtner, G. C., Longaker, M. T., Lorenz, H. P. 2014

  Abstract

  Early fetuses heal wounds without the formation of a scar. Many studies have attempted to explain this remarkable phenomenon. However, the exact mechanism remains unknown. Herein, we examine the predominant cell types of the epidermis and dermis-the keratinocyte and fibroblast-during different stages of fetal development to better understand the changes that lead to scarring wound repair versus regeneration.Keratinocytes and fibroblasts were harvested and cultured from the dorsal skin of time-dated BALB/c fetuses. Total RNA was isolated and microarray analysis was performed using chips with 42,000 genes. Significance analysis of microarrays was used to select genes with >2-fold expression differences with a false discovery rate <2. Enrichment analysis was performed on significant genes to identify differentially expressed pathways.By comparing the gene expression profile of keratinocytes from E16 versus E18 fetuses, we identified 24 genes that were downregulated at E16. Analysis of E16 and E18 fibroblasts revealed 522 differentially expressed genes. Enrichment analysis showed the top 20 signaling pathways that were downregulated in E16 keratinocytes and upregulated or downregulated in E16 fibroblasts.Our data reveal 546 differentially expressed genes in keratinocytes and fibroblasts between the scarless and scarring transition. In addition, a total of 60 signaling pathways have been identified to be either upregulated or downregulated in these cell types. The genes and pathways recognized by our study may prove to be essential targets that may discriminate between fetal wound regeneration and adult wound repair.

  View details for DOI 10.1016/j.jss.2014.02.030

  View details for PubMedID 24726057

• Reduced BMPR2 expression induces GM-CSF translation and macrophage recruitment in humans and mice to exacerbate pulmonary hypertension. journal of experimental medicine Sawada, H., Saito, T., Nickel, N. P., Alastalo, T., Glotzbach, J. P., Chan, R., Haghighat, L., Fuchs, G., Januszyk, M., Cao, A., Lai, Y., Perez, V. d., Kim, Y., Wang, L., Chen, P., Spiekerkoetter, E., Mitani, Y., Gurtner, G. C., Sarnow, P., Rabinovitch, M. 2014; 211 (2): 263-280

  Abstract

  Idiopathic pulmonary arterial hypertension (PAH [IPAH]) is an insidious and potentially fatal disease linked to a mutation or reduced expression of bone morphogenetic protein receptor 2 (BMPR2). Because intravascular inflammatory cells are recruited in IPAH pathogenesis, we hypothesized that reduced BMPR2 enhances production of the potent chemokine granulocyte macrophage colony-stimulating factor (GM-CSF) in response to an inflammatory perturbation. When human pulmonary artery (PA) endothelial cells deficient in BMPR2 were stimulated with tumor necrosis factor (TNF), a twofold increase in GM-CSF was observed and related to enhanced messenger RNA (mRNA) translation. The mechanism was associated with disruption of stress granule formation. Specifically, loss of BMPR2 induced prolonged phospho-p38 mitogen-activated protein kinase (MAPK) in response to TNF, and this increased GADD34-PP1 phosphatase activity, dephosphorylating eukaryotic translation initiation factor (eIF2α), and derepressing GM-CSF mRNA translation. Lungs from IPAH patients versus unused donor controls revealed heightened PA expression of GM-CSF co-distributing with increased TNF and expanded populations of hematopoietic and endothelial GM-CSF receptor α (GM-CSFRα)-positive cells. Moreover, a 3-wk infusion of GM-CSF in mice increased hypoxia-induced PAH, in association with increased perivascular macrophages and muscularized distal arteries, whereas blockade of GM-CSF repressed these features. Thus, reduced BMPR2 can subvert a stress granule response, heighten GM-CSF mRNA translation, increase inflammatory cell recruitment, and exacerbate PAH.

  View details for DOI 10.1084/jem.20111741

  View details for PubMedID 24446489

• The embrace Device Significantly Decreases Scarring following Scar Revision Surgery in a Randomized Controlled Trial. Plastic and reconstructive surgery Lim, A. F., Weintraub, J., Kaplan, E. N., Januszyk, M., Cowley, C., McLaughlin, P., Beasley, B., Gurtner, G. C., Longaker, M. T. 2014; 133 (2): 398-405

  Abstract

  Mechanically offloading or shielding an incision significantly reduces scarring in both animal and first-in-human studies. Whether or not this strategy would be effective following scar revision surgery was previously unknown. In this article, the authors report that the embrace device, which uses principles of mechanomodulation, significantly improves aesthetic outcomes following scar revision surgery.A prospective, open-label, randomized, single-center study was conducted to evaluate the appearance of scars following revision and embrace treatment. Revision surgery was performed on 12 patients, each acting as his or her own control, and outcomes were assessed at 6 months. A visual analogue scale was used to evaluate each scar, rated by four independent surgeons who were not involved in the study.Evaluation of 6-month scar images by four independent surgeons using the visual analogue scale demonstrated a highly significant improvement in scar appearance following embrace treatment (p < 0.005).The embrace device represents a powerful new technology for significantly improving scar appearance following revision surgery.Therapeutic, II.

  View details for DOI 10.1097/01.prs.0000436526.64046.d0

  View details for PubMedID 24105084

• Aging disrupts cell subpopulation dynamics and diminishes the function of mesenchymal stem cells. Scientific reports Duscher, D., Rennert, R. C., Januszyk, M., Anghel, E., Maan, Z. N., Whittam, A. J., Perez, M. G., Kosaraju, R., Hu, M. S., Walmsley, G. G., Atashroo, D., Khong, S., Butte, A. J., Gurtner, G. C. 2014; 4: 7144-?

  Abstract

  Advanced age is associated with an increased risk of vascular morbidity, attributable in part to impairments in new blood vessel formation. Mesenchymal stem cells (MSCs) have previously been shown to play an important role in neovascularization and deficiencies in these cells have been described in aged patients. Here we utilize single cell transcriptional analysis to determine the effect of aging on MSC population dynamics. We identify an age-related depletion of a subpopulation of MSCs characterized by a pro-vascular transcriptional profile. Supporting this finding, we demonstrate that aged MSCs are also significantly compromised in their ability to support vascular network formation in vitro and in vivo. Finally, aged MSCs are unable to rescue age-associated impairments in cutaneous wound healing. Taken together, these data suggest that age-related changes in MSC population dynamics result in impaired therapeutic potential of aged progenitor cells. These findings have critical implications for therapeutic cell source decisions (autologous versus allogeneic) and indicate the necessity of strategies to improve functionality of aged MSCs.

  View details for DOI 10.1038/srep07144

  View details for PubMedID 25413454

• Understanding regulatory pathways of neovascularization in diabetes EXPERT REVIEW OF ENDOCRINOLOGY & METABOLISM Maan, Z. N., Rodrigues, M., Rennert, R. C., Whitmore, A., Duscher, D., Januszyk, M., Hu, M., Whittam, A. J., Davis, C. R., Gurtner, G. C. 2014; 9 (5): 487–501

  View details for DOI 10.1586/17446651.2014.938054

  View details for Web of Science ID 000420054600007

• High-Throughput Single-Cell Analysis for Wound Healing Applications. Advances in wound care Januszyk, M., Gurtner, G. C. 2013; 2 (9): 457-469

  Abstract

  Wound repair is a complex biological process that integrates multiple physiologic pathways to restore skin homeostasis after a wide array of gross and anatomical insults. As such, a scientific examination of the wound typically requires broad sampling of numerous factors and is commonly achieved through DNA microarray analysis.In the last several years, it has become increasingly evident that the granularity afforded by such traditional population-based assays may be insufficient to capture the complex relationships in heterogeneous processes such as those associated with wound healing and stem cell biology.Several emerging technologies have recently become available that permit high-throughput single-cell gene expression analysis in a manner which provides novel insights into the relationships of complex tissue. The most prominent among these employs microfluidic-based devices to achieve a high-resolution analysis of tissue samples.The intrinsically heterogeneous nature of injured tissue, in conjunction with its temporal dynamics, makes wound repair and tissue regeneration an attractive target for high-throughput single-cell analysis. Given the staggering costs associated with chronic and non-healing wounds, the development of predictive and diagnostic tools using this technology would likely be attractive to healthcare providers.

  View details for PubMedID 24527358

• Cell surface marker profiling of human adipose derived stem cells using single cell transcriptional analysis identifies heterogeneous subpopulations Sorkin, M., Rennert, R. C., Januszyk, M., Glotzbach, J. P., Chung, M. T., Longaker, M. T., Gurtner, G. C. ELSEVIER SCIENCE INC. 2013: S96–S97

  View details for DOI 10.1016/j.jamcollsurg.2013.07.219

  View details for Web of Science ID 000325577900190

• Molecular analysis and differentiation capacity of adipose-derived stem cells from lymphedema tissue. Plastic and reconstructive surgery Levi, B., Glotzbach, J. P., Sorkin, M., Hyun, J., Januszyk, M., Wan, D. C., Li, S., Nelson, E. R., Longaker, M. T., Gurtner, G. C. 2013; 132 (3): 580-589

  Abstract

  Many breast cancer patients are plagued by the disabling complication of upper limb lymphedema after axillary surgery. Conservative treatments using massage and compression therapy do not offer a lasting relief, as they fail to address the chronic transformation of edema into excess adipose tissue. Liposuction to address the adipose nature of the lymphedema has provided an opportunity for a detailed analysis of the stromal fraction of lymphedema-associated fat to clarify the molecular mechanisms for this adipogenic transformation.Adipose-derived stem cells were harvested from human lipoaspirate of the upper extremity from age-matched patients with lymphedema (n = 3) or subcutaneous adipose tissue from control patients undergoing cosmetic procedures (n = 3). Immediately after harvest, adipose-derived stem cells were analyzed using single-cell transcriptional profiling techniques. Osteogenic, adipogenic, and vasculogenic gene expression and differentiation were assessed by quantitative real-time polymerase chain reaction and standard in vitro differentiation assays.Differential transcriptional clusters of adipose-derived stem cells were found between lymphedema and subcutaneous fat. Interestingly, lymphedema-associated stem cells had a much higher adipogenic gene expression and enhanced ability to undergo adipogenic differentiation. Conversely, they had lower vasculogenic gene expression and diminished capability to form tubules in vitro, whereas the osteogenic differentiation capacity was not significantly altered.Adipose-derived stem cells from extremities affected by lymphedema appear to exhibit transcriptional profiles similar to those of abdominal adipose-derived stem cells; however, their adipogenic differentiation potential is strongly increased and their vasculogenic capacity is compromised. These results suggest that the underlying pathophysiology of lymphedema drives adipose-derived stem cells toward adipogenic differentiation.

  View details for DOI 10.1097/PRS.0b013e31829ace13

  View details for PubMedID 23985633

• Tacrolimus fails to regulate collagen expression in dermal fibroblasts. journal of surgical research Wong, V. W., You, F., Januszyk, M., Kuang, A. A. 2013; 184 (1): 678-690

  Abstract

  BACKGROUND: The purpose of this study was to investigate the effects of tacrolimus on human fibroblasts derived from unwounded skin, hypertrophic scars (HTS), and keloids. We hypothesized that tacrolimus, a potent anti-inflammatory and immunosuppressant drug known to attenuate solid organ transplant fibrosis, would block collagen expression in human dermal fibroblasts. METHODS: We performed genomewide microarray analysis on human dermal fibroblasts treated with tacrolimus in vitro. We used principal component analysis and hierarchical clustering to identify targets regulated by tacrolimus. We performed quantitative polymerase chain reaction to validate the effect of tacrolimus on collagen 1 and 3 expression. RESULTS: We identified 62, 136, and 185 gene probes on microarray analysis that were significantly regulated (P < 0.05) by tacrolimus in normal, HTS, and keloid fibroblasts, respectively. Collagen pathways were not blocked after tacrolimus exposure in any of the fibroblast groups; we validated these findings using quantitative polymerase chain reaction for collagen 1 and 3. Microarray gene expression of NME/NM23 nucleoside diphosphate kinase 1 and heterogeneous nuclear ribonucleoprotein H3-2H9 were significantly downregulated (P < 0.05) by tacrolimus in both HTS and keloid fibroblast populations but not normal fibroblasts. CONCLUSIONS: Tacrolimus does not modulate the expression of collagen 1 or 3 in human dermal fibroblasts in vitro. Microarray gene expression of NME/NM23 nucleoside diphosphate kinase 1 and heterogeneous nuclear ribonucleoprotein H3-2H9 are blocked by tacrolimus in pathologic fibroblasts but not normal fibroblasts, and may represent novel genes underlying HTS and keloid pathogenesis. Tacrolimus-based anti-fibrotics might prove more effective if non-fibroblast populations such as inflammatory cells and keratinocytes are targeted.

  View details for DOI 10.1016/j.jss.2013.04.006

  View details for PubMedID 23647800

• Micro-Computed Tomography Evaluation of Human Fat Grafts in Nude Mice TISSUE ENGINEERING PART C-METHODS Chung, M. T., Hyun, J. S., Lo, D. D., Montoro, D. T., Hasegawa, M., Levi, B., Januszyk, M., Longaker, M. T., Wan, D. C. 2013; 19 (3): 227-232

  Abstract

  Although autologous fat grafting has revolutionized the field of soft tissue reconstruction and augmentation, long-term maintenance of fat grafts is unpredictable. Recent studies have reported survival rates of fat grafts to vary anywhere between 10% and 80% over time. The present study evaluated the long-term viability of human fat grafts in a murine model using a novel imaging technique allowing for in vivo volumetric analysis.Human fat grafts were prepared from lipoaspirate samples using the Coleman technique. Fat was injected subcutaneously into the scalp of 10 adult Crl:NU-Foxn1(nu) CD-1 male mice. Micro-computed tomography (CT) was performed immediately following injection and then weekly thereafter. Fat volume was rendered by reconstructing a three-dimensional (3D) surface through cubic-spline interpolation. Specimens were also harvested at various time points and sections were prepared and stained with hematoxylin and eosin (H&E), for macrophages using CD68 and for the cannabinoid receptor 1 (CB1). Finally, samples were explanted at 8- and 12-week time points to validate calculated micro-CT volumes.Weekly CT scanning demonstrated progressive volume loss over the time course. However, volumetric analysis at the 8- and 12-week time points stabilized, showing an average of 62.2% and 60.9% survival, respectively. Gross analysis showed the fat graft to be healthy and vascularized. H&E analysis and staining for CD68 showed minimal inflammatory reaction with viable adipocytes. Immunohistochemical staining with anti-human CB1 antibodies confirmed human origin of the adipocytes.Studies assessing the fate of autologous fat grafts in animals have focused on nonimaging modalities, including histological and biochemical analyses, which require euthanasia of the animals. In this study, we have demonstrated the ability to employ micro-CT for 3D reconstruction and volumetric analysis of human fat grafts in a mouse model. Importantly, this model provides a platform for subsequent study of fat manipulation and soft tissue engineering.

  View details for DOI 10.1089/ten.tec.2012.0371

  View details for Web of Science ID 000314179900006

  View details for PubMedID 22916732

  View details for PubMedCentralID PMC3557441

• Cellular response to a novel fetal acellular collagen matrix: implications for tissue regeneration. International journal of biomaterials Rennert, R. C., Sorkin, M., Garg, R. K., Januszyk, M., Gurtner, G. C. 2013; 2013: 527957-?

  Abstract

  Introduction. PriMatrix (TEI Biosciences Inc., Boston, MA, USA) is a novel acellular collagen matrix derived from fetal bovine dermis that is designed for use in partial- and full-thickness wounds. This study analyzes the cellular response to PriMatrix in vivo, as well as the ability of this matrix to facilitate normal tissue regeneration. Methods. Five by five mm squares of rehydrated PriMatrix were implanted in a subcutaneous fashion on the dorsum of wild-type mice. Implant site tissue was harvested for histology, immunohistochemistry (IHC), and flow cytometric analyses at multiple time points until day 28. Results. PriMatrix implants were found to go through a biological progression initiated by a transient infiltrate of inflammatory cells, followed by mesenchymal cell recruitment and vascular development. IHC analysis revealed that the majority of the implanted fetal dermal collagen fibers persisted through day 28 but underwent remodeling and cellular repopulation to form tissue with a density and morphology consistent with healthy dermis. Conclusions. PriMatrix implants undergo progressive in vivo remodeling, facilitating the regeneration of histologically normal tissue through a mild inflammatory and progenitor cell response. Regeneration of normal tissue is especially important in a wound environment, and these findings warrant further investigation of PriMatrix in this setting.

  View details for DOI 10.1155/2013/527957

  View details for PubMedID 23970899

  View details for PubMedCentralID PMC3736474

• Single cell analysis reveals phenotypically distinct sub-populations in putative endothelial progenitor cells Surgical Forum at the 98th Annual Clinical Congress of the American-College-of-Surgeons / 67th Annual Sessions of the Owen H Wangensteen Forum on Fundamental Surgical Problems Chen, J., Januszyk, M., Sorkin, M., Gurtner, G. C. ELSEVIER SCIENCE INC. 2012: S93–S93

  View details for Web of Science ID 000308909600195

• Focal adhesion kinase links mechanical force to skin fibrosis via inflammatory signaling. Nature medicine Wong, V. W., Rustad, K. C., Akaishi, S., Sorkin, M., Glotzbach, J. P., Januszyk, M., Nelson, E. R., Levi, K., Paterno, J., Vial, I. N., Kuang, A. A., Longaker, M. T., Gurtner, G. C. 2012; 18 (1): 148-152

  Abstract

  Exuberant fibroproliferation is a common complication after injury for reasons that are not well understood. One key component of wound repair that is often overlooked is mechanical force, which regulates cell-matrix interactions through intracellular focal adhesion components, including focal adhesion kinase (FAK). Here we report that FAK is activated after cutaneous injury and that this process is potentiated by mechanical loading. Fibroblast-specific FAK knockout mice have substantially less inflammation and fibrosis than control mice in a model of hypertrophic scar formation. We show that FAK acts through extracellular-related kinase (ERK) to mechanically trigger the secretion of monocyte chemoattractant protein-1 (MCP-1, also known as CCL2), a potent chemokine that is linked to human fibrotic disorders. Similarly, MCP-1 knockout mice form minimal scars, indicating that inflammatory chemokine pathways are a major mechanism by which FAK mechanotransduction induces fibrosis. Small-molecule inhibition of FAK blocks these effects in human cells and reduces scar formation in vivo through attenuated MCP-1 signaling and inflammatory cell recruitment. These findings collectively indicate that physical force regulates fibrosis through inflammatory FAK-ERK-MCP-1 pathways and that molecular strategies targeting FAK can effectively uncouple mechanical force from pathologic scar formation.

  View details for DOI 10.1038/nm.2574

  View details for PubMedID 22157678

• Focal adhesion kinase links mechanical force to skin fibrosis via inflammatory signaling NATURE MEDICINE Wong, V. W., Rustad, K. C., Akaishi, S., Sorkin, M., Glotzbach, J. P., Januszyk, M., Nelson, E. R., Levi, K., Paterno, J., Vial, I. N., Kuang, A. A., Longaker, M. T., Gurtner, G. C. 2012; 18 (1): 148-152

  Abstract

  Exuberant fibroproliferation is a common complication after injury for reasons that are not well understood. One key component of wound repair that is often overlooked is mechanical force, which regulates cell-matrix interactions through intracellular focal adhesion components, including focal adhesion kinase (FAK). Here we report that FAK is activated after cutaneous injury and that this process is potentiated by mechanical loading. Fibroblast-specific FAK knockout mice have substantially less inflammation and fibrosis than control mice in a model of hypertrophic scar formation. We show that FAK acts through extracellular-related kinase (ERK) to mechanically trigger the secretion of monocyte chemoattractant protein-1 (MCP-1, also known as CCL2), a potent chemokine that is linked to human fibrotic disorders. Similarly, MCP-1 knockout mice form minimal scars, indicating that inflammatory chemokine pathways are a major mechanism by which FAK mechanotransduction induces fibrosis. Small-molecule inhibition of FAK blocks these effects in human cells and reduces scar formation in vivo through attenuated MCP-1 signaling and inflammatory cell recruitment. These findings collectively indicate that physical force regulates fibrosis through inflammatory FAK-ERK-MCP-1 pathways and that molecular strategies targeting FAK can effectively uncouple mechanical force from pathologic scar formation.

  View details for DOI 10.1038/nm.2574

  View details for Web of Science ID 000299018600041

• Mechanical force prolongs acute inflammation via T-cell-dependent pathways during scar formation FASEB JOURNAL Wong, V. W., Paterno, J., Sorkin, M., Glotzbach, J. P., Levi, K., Januszyk, M., Rustad, K. C., Longaker, M. T., Gurtner, G. C. 2011; 25 (12): 4498-4510

  Abstract

  Mechanical force significantly modulates both inflammation and fibrosis, yet the fundamental mechanisms that regulate these interactions remain poorly understood. Here we performed microarray analysis to compare gene expression in mechanically loaded wounds vs. unloaded control wounds in an established murine hypertrophic scar (HTS) model. We identified 853 mechanically regulated genes (false discovery rate <2) at d 14 postinjury, a subset of which were enriched for T-cell-regulated pathways. To substantiate the role of T cells in scar mechanotransduction, we applied the HTS model to T-cell-deficient mice and wild-type mice. We found that scar formation in T-cell-deficient mice was reduced by almost 9-fold (P < 0.001) with attenuated epidermal (by 2.6-fold, P < 0.01) and dermal (3.9-fold, P < 0.05) proliferation. Mechanical stimulation was highly associated with sustained T-cell-dependent Th2 cytokine (IL-4 and IL-13) and chemokine (MCP-1) signaling. Further, T-cell-deficient mice failed to recruit systemic inflammatory cells such as macrophages or monocytic fibroblast precursors in response to mechanical loading. These findings indicate that T-cell-regulated fibrogenic pathways are highly mechanoresponsive and suggest that mechanical forces induce a chronic-like inflammatory state through immune-dependent activation of both local and systemic cell populations.

  View details for DOI 10.1096/fj.10-178087

  View details for Web of Science ID 000298138100040

  View details for PubMedID 21911593

• Reduced BMPR2 Increases GM-CSF mRNA Translation by Inhibiting eIF2 alpha Mediated Stress Granule Formation and Propensity to Pulmonary Vascular Disease Scientific Sessions of the American-Heart-Association/Resuscitation Science Symposium Sawada, H., Alastalo, T., Glotzbach, J. P., Chan, R., Fuchs, G., Januszyk, M., Lai, Y., Perez, V. D., Saito, T., Spiekerkoetter, E., Wang, L., Gurtner, G. C., Sarnow, P., Rabinovitch, M. LIPPINCOTT WILLIAMS & WILKINS. 2011

  View details for Web of Science ID 000299738703348

• CD105 Protein Depletion Enhances Human Adipose-derived Stromal Cell Osteogenesis through Reduction of Transforming Growth Factor beta 1 (TGF-beta 1) Signaling JOURNAL OF BIOLOGICAL CHEMISTRY Levi, B., Wan, D. C., Glotzbach, J. P., Hyun, J., Januszyk, M., Montoro, D., Sorkin, M., James, A. W., Nelson, E. R., Li, S., Quarto, N., Lee, M., Gurtner, G. C., Longaker, M. T. 2011; 286 (45): 39497-39509

  Abstract

  Clinically available sources of bone for repair and reconstruction are limited by the accessibility of autologous grafts, infectious risks of cadaveric materials, and durability of synthetic substitutes. Cell-based approaches for skeletal regeneration can potentially fill this need, and adipose tissue represents a promising source for development of such therapies. Here, we enriched for an osteogenic subpopulation of cells derived from human subcutaneous adipose tissue utilizing microfluidic-based single cell transcriptional analysis and fluorescence-activated cell sorting (FACS). Statistical analysis of single cell transcriptional profiles demonstrated that low expression of endoglin (CD105) correlated with a subgroup of adipose-derived cells with increased osteogenic gene expression. FACS-sorted CD105(low) cells demonstrated significantly enhanced in vitro osteogenic differentiation and in vivo bone regeneration when compared with either CD105(high) or unsorted cells. Evaluation of the endoglin pathway suggested that enhanced osteogenesis among CD105(low) adipose-derived cells is likely due to identification of a subpopulation with lower TGF-β1/Smad2 signaling. These findings thus highlight a potential avenue to promote osteogenesis in adipose-derived mesenchymal cells for skeletal regeneration.

  View details for DOI 10.1074/jbc.M111.256529

  View details for PubMedID 21949130

• An Information Theoretic, Microfluidic-Based Single Cell Analysis Permits Identification of Subpopulations among Putatively Homogeneous Stem Cells PLOS ONE Glotzbach, J. P., Januszyk, M., Vial, I. N., Wong, V. W., Gelbard, A., Kalisky, T., Thangarajah, H., Longaker, M. T., Quake, S. R., Chu, G., Gurtner, G. C. 2011; 6 (6)

  Abstract

  An incomplete understanding of the nature of heterogeneity within stem cell populations remains a major impediment to the development of clinically effective cell-based therapies. Transcriptional events within a single cell are inherently stochastic and can produce tremendous variability, even among genetically identical cells. It remains unclear how mammalian cellular systems overcome this intrinsic noisiness of gene expression to produce consequential variations in function, and what impact this has on the biologic and clinical relevance of highly 'purified' cell subgroups. To address these questions, we have developed a novel method combining microfluidic-based single cell analysis and information theory to characterize and predict transcriptional programs across hundreds of individual cells. Using this technique, we demonstrate that multiple subpopulations exist within a well-studied and putatively homogeneous stem cell population, murine long-term hematopoietic stem cells (LT-HSCs). These subgroups are defined by nonrandom patterns that are distinguishable from noise and are consistent with known functional properties of these cells. We anticipate that this analytic framework can also be applied to other cell types to elucidate the relationship between transcriptional and phenotypic variation.

  View details for DOI 10.1371/journal.pone.0021211

  View details for Web of Science ID 000292033700046

  View details for PubMedID 21731674

  View details for PubMedCentralID PMC3120839

• Engineered Pullulan-Collagen Composite Dermal Hydrogels Improve Early Cutaneous Wound Healing TISSUE ENGINEERING PART A Wong, V. W., Rustad, K. C., Galvez, M. G., Neofyotou, E., Glotzbach, J. P., Januszyk, M., Major, M. R., Sorkin, M., Longaker, M. T., Rajadas, J., Gurtner, G. C. 2011; 17 (5-6): 631-644

  Abstract

  New strategies for skin regeneration are needed to address the significant medical burden caused by cutaneous wounds and disease. In this study, pullulan-collagen composite hydrogel matrices were fabricated using a salt-induced phase inversion technique, resulting in a structured yet soft scaffold for skin engineering. Salt crystallization induced interconnected pore formation, and modification of collagen concentration permitted regulation of scaffold pore size. Hydrogel architecture recapitulated the reticular distribution of human dermal matrix while maintaining flexible properties essential for skin applications. In vitro, collagen hydrogel scaffolds retained their open porous architecture and viably sustained human fibroblasts and murine mesenchymal stem cells and endothelial cells. In vivo, hydrogel-treated murine excisional wounds demonstrated improved wound closure, which was associated with increased recruitment of stromal cells and formation of vascularized granulation tissue. In conclusion, salt-induced phase inversion techniques can be used to create modifiable pullulan-collagen composite dermal scaffolds that augment early wound healing. These novel biomatrices can potentially serve as a structured delivery template for cells and biomolecules in regenerative skin applications.

  View details for DOI 10.1089/ten.tea.2010.0298

  View details for Web of Science ID 000287801600005

  View details for PubMedID 20919949

• Statistics in Medicine PLASTIC AND RECONSTRUCTIVE SURGERY Januszyk, M., Gurtner, G. C. 2011; 127 (1): 437-444

  Abstract

  The scope of biomedical research has expanded rapidly during the past several decades, and statistical analysis has become increasingly necessary to understand the meaning of large and diverse quantities of raw data. As such, a familiarity with this lexicon is essential for critical appraisal of medical literature. This article attempts to provide a practical overview of medical statistics, with an emphasis on the selection, application, and interpretation of specific tests. This includes a brief review of statistical theory and its nomenclature, particularly with regard to the classification of variables. A discussion of descriptive methods for data presentation is then provided, followed by an overview of statistical inference and significance analysis, and detailed treatment of specific statistical tests and guidelines for their interpretation.

  View details for DOI 10.1097/PRS.0b013e3181f95dd2

  View details for Web of Science ID 000285992100060

  View details for PubMedID 21200241

• Anatomical and Technical Tips for Use of the Superficial Inferior Epigastric Artery (SIEA) Flap in Breast Reconstructive Surgery JOURNAL OF RECONSTRUCTIVE MICROSURGERY Dorafshar, A. H., Januszyk, M., Song, D. H. 2010; 26 (6): 381-389

  Abstract

  Techniques for autologous breast reconstruction have evolved to minimize donor-site morbidity and reduce flap-specific complications. When available, the superficial inferior epigastric artery (SIEA) flap represents the optimal method to achieve the former. However, many microsurgeons have been reluctant to adopt this procedure due to technical challenges inherent to the surgery, as well as concerns with the intrinsic capacity of the superficial vessel system to adequately support this flap. This article sets forth a simple approach to the SIEA flap harvest and demonstrates that favorable results may be achieved even for small caliber vessels. A total of 46 patients underwent 53 SIEA breast reconstructions over a 6-year period using a modified approach for pedicle dissection and arterial inclusion criteria solely on the basis of presence of a palpable pulse. Average pedicle length harvested for all SIEA flaps was 6.07 cm; and mean arterial (0.96 mm) and venous (2.27 mm) diameters represent the lowest published values. Three flaps (5.7%) demonstrated fat necrosis or partial flap necrosis, with one (1.9%) complete flap loss. These results compare favorably with those of previous SIEA series employing diameter-based selection criteria, suggesting that the presence of a palpable arterial pulse may be sufficient to permit successful utilization of this flap.

  View details for DOI 10.1055/s-0030-1249604

  View details for Web of Science ID 000279057300005

  View details for PubMedID 20301060

• HIF-1 alpha dysfunction in diabetes CELL CYCLE Thangarajah, H., Vial, I. N., Grogan, R. H., Yao, D., Shi, Y., Januszyk, M., Galiano, R. D., Chang, E. I., Galvez, M. G., Glotzbach, J. P., Wong, V. W., Brownlee, M., Gurtner, G. C. 2010; 9 (1): 75-79

  Abstract

  Diabetic wounds are a significant public health burden, with slow or nonhealing diabetic foot ulcers representing the leading cause of non-traumatic lower limb amputation in developed countries. These wounds heal poorly as a result of compromised blood vessel formation in response to ischemia. We have recently shown that this impairment in neovascularization results from a high glucose-induced defect in transactivation of hypoxia-inducible factor-1alpha (HIF-1alpha), the transcription factor regulating vascular endothelial growth factor (VEGF) expression. HIF-1 dysfunction is the end result of reactive oxygen species-induced modification of its coactivator p300 by the glycolytic metabolite methylglyoxal. Use of the iron chelator-antioxidant deferoxamine (DFO) reversed these effects and normalized healing of humanized diabetic wounds in mice. Here, we present additional data demonstrating that HIF-1alpha activity, not stability, is impaired in the high glucose environment. We demonstrate that high glucose-induced impairments in HIF-1alpha transactivation persist even in the setting of constitutive HIF-1alpha protein overexpression. Further, we show that high glucose-induced hydroxylation of the C-terminal transactivation domain of HIF-1alpha (the primary pathway regulating HIF-1alpha/p300 binding) does not alter HIF-1alpha activity. We extend our study of DFO's therapeutic efficacy in the treatment of impaired wound healing by demonstrating improvements in tissue viability in diabetic mice with DFO-induced increases in VEGF expression and vascular proliferation. Since DFO has been in clinical use for decades, the potential of this drug to treat a variety of ischemic conditions in humans can be evaluated relatively quickly.

  View details for Web of Science ID 000273236800025

  View details for PubMedID 20016290

• The molecular basis for impaired hypoxia-induced VEGF expression in diabetic tissues PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Thangarajah, H., Yao, D., Chang, E. I., Shi, Y., Jazayeri, L., Vial, I. N., Galiano, R. D., Du, X., Grogan, R., Galvez, M. G., Januszyk, M., Brownlee, M., Gurtner, G. C. 2009; 106 (32): 13505-13510

  Abstract

  Diabetes is associated with poor outcomes following acute vascular occlusive events. This results in part from a failure to form adequate compensatory microvasculature in response to ischemia. Since vascular endothelial growth factor (VEGF) is an essential mediator of neovascularization, we examined whether hypoxic up-regulation of VEGF was impaired in diabetes. Both fibroblasts isolated from type 2 diabetic patients, and normal fibroblasts exposed chronically to high glucose, were defective in their capacity to up-regulate VEGF in response to hypoxia. In vivo, diabetic animals demonstrated an impaired ability to increase VEGF production in response to soft tissue ischemia. This resulted from a high glucose-induced decrease in transactivation by the transcription factor hypoxia-inducible factor-1alpha (HIF-1alpha), which mediates hypoxia-stimulated VEGF expression. Decreased HIF-1alpha functional activity was specifically caused by impaired HIF-1alpha binding to the coactivator p300. We identify covalent modification of p300 by the dicarbonyl metabolite methylglyoxal as being responsible for this decreased association. Administration of deferoxamine abrogated methylglyoxal conjugation, normalizing both HIF-1alpha/p300 interaction and transactivation by HIF-1alpha. In diabetic mice, deferoxamine promoted neovascularization and enhanced wound healing. These findings define molecular defects that underlie impaired VEGF production in diabetic tissues and offer a promising direction for therapeutic intervention.

  View details for DOI 10.1073/pnas.0906670106

  View details for Web of Science ID 000268877300065

  View details for PubMedID 19666581

  View details for PubMedCentralID PMC2726398

• IFATS Collection: Adipose Stromal Cells Adopt a Proangiogenic Phenotype Under the Influence of Hypoxia STEM CELLS Thangarajah, H., Vial, I. N., Chang, E., El-Ftesi, S., Januszyk, M., Chang, E. I., Paterno, J., Neofytou, E., Longaker, M. T., Gurtner, G. C. 2009; 27 (1): 266-274

  Abstract

  Evolving evidence suggests a possible role for adipose stromal cells (ASCs) in adult neovascularization, although the specific cues that stimulate their angiogenic behavior are poorly understood. We evaluated the effect of hypoxia, a central mediator of new blood vessel development within ischemic tissue, on proneovascular ASC functions. Murine ASCs were exposed to normoxia (21% oxygen) or hypoxia (5%, 1% oxygen) for varying lengths of time. Vascular endothelial growth factor (VEGF) secretion by ASCs increased as an inverse function of oxygen tension, with progressively higher VEGF expression at 21%, 5%, and 1% oxygen, respectively. Greater VEGF levels were also associated with longer periods in culture. ASCs were able to migrate towards stromal cell-derived factor (SDF)-1, a chemokine expressed by ischemic tissue, with hypoxia augmenting ASC expression of the SDF-1 receptor (CXCR4) and potentiating ASC migration. In vivo, ASCs demonstrated the capacity to proliferate in response to a hypoxic insult remote from their resident niche, and this was supported by in vitro studies showing increasing ASC proliferation with greater degrees of hypoxia. Hypoxia did not significantly alter the expression of endothelial surface markers by ASCs. However, these cells did assume an endothelial phenotype as evidenced by their ability to tubularize when seeded with differentiated endothelial cells on Matrigel. Taken together, these data suggest that ASCs upregulate their proneovascular activity in response to hypoxia, and may harbor the capacity to home to ischemic tissue and function cooperatively with existing vasculature to promote angiogenesis.

  View details for DOI 10.1634/stemcells.2008-0276

  View details for Web of Science ID 000263032400030

  View details for PubMedID 18974212