Stanford Advisors


All Publications


  • A multivariable miRNA signature delineates the systemic hemodynamic impact of arteriovenous shunt placement in a pilot study. Scientific reports Henn, D., Abu-Halima, M., Kahraman, M., Falkner, F., Fischer, K. S., Barrera, J. A., Chen, K., Gurtner, G. C., Keller, A., Kneser, U., Meese, E., Schmidt, V. J. 2020; 10 (1): 21809

    Abstract

    Arteriovenous (AV) fistulas for hemodialysis can lead to cardiac volume loading and increased serum brain natriuretic peptide (BNP) levels. Whether short-term AV loop placement in patients undergoing microsurgery has an impact on cardiac biomarkers and circulating microRNAs (miRNAs), potentially indicating an increased hemodynamic risk, remains elusive. Fifteen patients underwent AV loop placement with delayed free flap anastomosis for microsurgical reconstructions of lower extremity soft-tissue defects. N-terminal pro-BNP (NT-proBNP), copeptin (CT-proAVP), and miRNA expression profiles were determined in the peripheral blood before and after AV loop placement. MiRNA expression in the blood was correlated with miRNA expression from AV loop vascular tissue. Serum NT-proBNP and copeptin levels exceeded the upper reference limit after AV loop placement, with an especially strong NT-proBNP increase in patients with preexistent cardiac diseases. A miRNA signature of 4 up-regulated (miR-3198, miR-3127-5p, miR-1305, miR-1288-3p) and 2 down-regulated miRNAs (miR30a-5p, miR-145-5p) which are related to cardiovascular physiology, showed a significant systemic deregulation in blood and venous tissue after AV loop placement. AV loop placement causes serum elevations of NT-proBNP, copeptin as well as specific circulating miRNAs, indicating a potentially increased hemodynamic risk for patients with cardiovascular comorbidities, if free flap anastomosis is delayed.

    View details for DOI 10.1038/s41598-020-78905-y

    View details for PubMedID 33311598

  • Tissue Engineering of Axially Vascularized Soft-Tissue Flaps with a Poly-(ɛ-Caprolactone) Nanofiber-Hydrogel Composite. Advances in wound care Henn, D., Chen, K., Fischer, K., Rauh, A., Barrera, J. A., Kim, Y. J., Martin, R. A., Hannig, M., Niedoba, P., Reddy, S. K., Mao, H. Q., Kneser, U., Gurtner, G. C., Sacks, J. M., Schmidt, V. J. 2020; 9 (7): 365-377

    Abstract

    Objective: To develop a novel approach for tissue engineering of soft-tissue flaps suitable for free microsurgical transfer, using an injectable nanofiber hydrogel composite (NHC) vascularized by an arteriovenous (AV) loop. Approach: A rat AV loop model was used for tissue engineering of vascularized soft-tissue flaps. NHC or collagen-elastin (CE) scaffolds were implanted into isolation chambers together with an AV loop and explanted after 15 days. Saphenous veins were implanted into the scaffolds as controls. Neoangiogenesis, ultrastructure, and protein expression of SYNJ2BP, EPHA2, and FOXC1 were analyzed by immunohistochemistry and compared between the groups. Rheological properties were compared between the two scaffolds and native human adipose tissue. Results: A functional neovascularization was evident in NHC flaps with its amount being comparable with CE flaps. Scanning electron microscopy revealed a strong mononuclear cell infiltration along the nanofibers in NHC flaps and a trend toward higher fiber alignment compared with CE flaps. SYNJ2BP and EPHA2 expression in endothelial cells (ECs) was lower in NHC flaps compared with CE flaps, whereas FOXC1 expression was increased in NHC flaps. Compared with the stiffer CE flaps, the NHC flaps showed similar rheological properties to native human adipose tissue. Innovation: This is the first study to demonstrate the feasibility of tissue engineering of soft-tissue flaps with similar rheological properties as human fat, suitable for microsurgical transfer using an injectable nanofiber hydrogel composite. Conclusions: The injectable NHC scaffold is suitable for tissue engineering of axially vascularized soft-tissue flaps with a solid neovascularization, strong cellular infiltration, and biomechanical properties similar to human fat. Our data indicate that SYNJ2BP, EPHA2, and FOXC1 are involved in AV loop-associated angiogenesis and that the scaffold material has an impact on protein expression in ECs.

    View details for DOI 10.1089/wound.2019.0975

    View details for PubMedID 32587789

    View details for PubMedCentralID PMC7307685

  • 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
  • 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
  • Tissue Engineering of Axially Vascularized Soft-Tissue Flaps with a Poly-(e-Caprolactone) Nanofiber-Hydrogel Composite ADVANCES IN WOUND CARE Henn, D., Chen, K., Fischer, K., Rauh, A., Barrera, J. A., Kim, Y., Martin, R., Hannig, M., Niedoba, P., Reddy, S., Mao, H., Kneser, U., Gurtner, G., Sacks, J. M., Schmidt, V. J. 2020