Academic Appointments


Administrative Appointments


  • Director, Comparative Medicine Necropsy Service (2018 - Present)

Honors & Awards


  • Department of Comparative Medicine Distinguished Clinician Award, Stanford University School of Medicine (2018)
  • Dr. Donald R. Cordy Prize in Veterinary Anatomic Pathology, University of California, Davis (2016)
  • Gerald V. Ling Award - Outstanding Small Animal Research Study and Presentation, University of California, Davis (2016)
  • Henry L. Foster DVM Scholar, Tufts Cummings School of Veterinary Medicine (2012-2013)
  • Norman J. MacLeod Endowed Scholar, Tufts Cummings School of Veterinary Medicine (2012)

Boards, Advisory Committees, Professional Organizations


  • Member, Geropathology Research Network (2017 - Present)
  • Member, Digital Pathology Association (2017 - Present)
  • Member, American College of Veterinary Pathologists (2016 - Present)

Professional Education


  • Fellow, Stanford University School of Medicine, Post-Doctoral Research Fellowship (2018)
  • Diplomate, American College of Veterinary Pathologists (ACVP), Anatomic Pathology (2016)
  • Resident, University of California - Davis, Anatomic Pathology (2016)
  • DVM, Tufts University, Veterinary Medicine (2013)
  • BA, Connecticut College, Behavioral Neuroscience (2007)

Graduate and Fellowship Programs


All Publications


  • Xist ribonucleoproteins promote female sex-biased autoimmunity. Cell Dou, D. R., Zhao, Y., Belk, J. A., Zhao, Y., Casey, K. M., Chen, D. C., Li, R., Yu, B., Srinivasan, S., Abe, B. T., Kraft, K., Hellström, C., Sjöberg, R., Chang, S., Feng, A., Goldman, D. W., Shah, A. A., Petri, M., Chung, L. S., Fiorentino, D. F., Lundberg, E. K., Wutz, A., Utz, P. J., Chang, H. Y. 2024; 187 (3): 733-749.e16

    Abstract

    Autoimmune diseases disproportionately affect females more than males. The XX sex chromosome complement is strongly associated with susceptibility to autoimmunity. Xist long non-coding RNA (lncRNA) is expressed only in females to randomly inactivate one of the two X chromosomes to achieve gene dosage compensation. Here, we show that the Xist ribonucleoprotein (RNP) complex comprising numerous autoantigenic components is an important driver of sex-biased autoimmunity. Inducible transgenic expression of a non-silencing form of Xist in male mice introduced Xist RNP complexes and sufficed to produce autoantibodies. Male SJL/J mice expressing transgenic Xist developed more severe multi-organ pathology in a pristane-induced lupus model than wild-type males. Xist expression in males reprogrammed T and B cell populations and chromatin states to more resemble wild-type females. Human patients with autoimmune diseases displayed significant autoantibodies to multiple components of XIST RNP. Thus, a sex-specific lncRNA scaffolds ubiquitous RNP components to drive sex-biased immunity.

    View details for DOI 10.1016/j.cell.2023.12.037

    View details for PubMedID 38306984

  • Exploring deep learning for estimating the isoeffective dose of FLASH irradiation from mouse intestinal histology images. International journal of radiation oncology, biology, physics Fu, J., Yang, Z., Melemenidis, S., Viswanathan, V., Dutt, S., Manjappa, R., Lau, B., Soto, L. A., Ashraf, R., Skinner, L., Yu, S. J., Surucu, M., Casey, K. M., Rankin, E. B., Graves, E., Lu, W., Loo, B. W., Gu, X. 2024

    Abstract

    Ultra-high dose rate (FLASH) irradiation has been reported to reduce normal tissue damage compared with conventional dose rate (CONV) irradiation without compromising tumor control. This proof-of-concept study aims to develop a deep learning (DL) approach to quantify the FLASH isoeffective dose (dose of CONV that would be required to produce the same effect as the given physical FLASH dose) with post-irradiation mouse intestinal histological images.84 healthy C57BL/6J female mice underwent 16 MeV electron CONV (0.12Gy/s; n=41) or FLASH (200Gy/s; n=43) single fraction whole abdominal irradiation. Physical dose ranged from 12 to 16Gy for FLASH and 11 to 15Gy for CONV in 1Gy increments. 4 days after irradiation, 9 jejunum cross-sections from each mouse were H&E stained and digitized for histological analysis. CONV dataset was randomly split into training (n=33) and testing (n=8) datasets. ResNet101-based DL models were retrained using the CONV training dataset to estimate the dose based on histological features. The classical manual crypt counting (CC) approach was implemented for model comparison. Cross-section-wise mean squared error (CS-MSE) was computed to evaluate the dose estimation accuracy of both approaches. The validated DL model was applied to the FLASH dataset to map the physical FLASH dose into the isoeffective dose.The DL model achieved a CS-MSE of 0.20Gy2 on the CONV testing dataset compared with 0.40Gy2 of the CC approach. Isoeffective doses estimated by the DL model for FLASH doses of 12, 13, 14, 15, and 16 Gy were 12.19±0.46, 12.54±0.37, 12.69±0.26, 12.84±0.26, and 13.03±0.28 Gy, respectively.Our proposed DL model achieved accurate CONV dose estimation. The DL model results indicate that in the physical dose range of 13 to 16 Gy, the biological dose response of small intestinal tissue to FLASH irradiation is represented by a lower isoeffective dose compared to the physical dose. Our DL approach can be a tool for studying isoeffective doses of other radiation dose modifying interventions.

    View details for DOI 10.1016/j.ijrobp.2023.12.032

    View details for PubMedID 38171387

  • Epizootic of enterocolitis and clostridial overgrowth in NSG and NSG-related mouse strains. Veterinary pathology Arthur, J. D., Mullen, J. L., Uzal, F. A., Nagamine, C. M., Casey, K. M. 2023: 3009858231217197

    Abstract

    While the immunodeficient status of NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) and NSG-related mice provides utility for numerous research models, it also results in increased susceptibility to opportunistic pathogens. Over a 9-week period, a high rate of mortality was reported in a housing room of NSG and NSG-related mice. Diagnostics were performed to determine the underlying etiopathogenesis. Mice submitted for evaluation included those found deceased (n = 2), cage mates of deceased mice with or without diarrhea (n = 17), and moribund mice (n = 8). Grossly, mice exhibited small intestinal and cecal dilation with abundant gas and/or digesta (n = 18), serosal hemorrhage and congestion (n = 6), or were grossly normal (n = 3). Histologically, there was erosive to ulcerative enterocolitis (n = 7) of the distal small and large intestine or widespread individual epithelial cell death with luminal sloughing (n = 13) and varying degrees of submucosal edema and mucosal hyperplasia. Cecal dysbiosis, a reduction in typical filamentous bacteria coupled with overgrowth of bacterial rods, was identified in 18 of 24 (75%) mice. Clostridium spp. and Paeniclostridium sordellii were identified in 13 of 23 (57%) and 7 of 23 (30%) mice, respectively. Clostridium perfringens (7 of 23, 30%) was isolated most frequently. Toxinotyping of C. perfringens positive mice (n = 2) identified C. perfringens type A. Luminal immunoreactivity to several clostridial species was identified within lesioned small intestine by immunohistochemistry. Clinicopathologic findings were thus associated with overgrowth of various clostridial species, though direct causality could not be ascribed. A diet shift preceding the mortality event may have contributed to loss of intestinal homeostasis.

    View details for DOI 10.1177/03009858231217197

    View details for PubMedID 38140953

  • INTERNAL CAROTID INJECTION MODEL OF BRAIN METASTASIS DESCRIBES LEPTOMENINGEAL DISEASE Chernikova, S., Tsau, S., Wang, Y., Hartmann, G., Polyak, D., Bhambhvani, H., Kolluru, S., Thy Trinh, Casey, K., Johnson, E., Connolly, I., Recht, L., Ahn, G., Nagpal, S., Quake, S., Brown, J., Gephart, M. OXFORD UNIV PRESS INC. 2023
  • Subcutaneous choriocarcinomas in captive Amargosa voles (Microtus californicus scirpensis). Veterinary pathology Carrasco, S. E., Johnson, A. L., Casey, K. M., Allan, N., Reed, M., Foley, J. E., Imai, D. M. 2023: 3009858231203647

    Abstract

    Spontaneous choriocarcinomas are rare, highly vascular, malignant trophoblastic tumors that occur in humans and animals. This report describes the unusual spontaneous presentation of 4 choriocarcinomas within the subcutaneous tissues of 4, multiparous but nongravid, Amargosa voles (Microtus californicus scirpensis) from a captive breeding colony. Two subcutaneous neoplasms were composed of multifocal discohesive and infiltrative aggregates of medium to large trophoblasts and cytotrophoblasts within a fibrovascular stroma. Neoplastic cells were associated with variably sized thrombi and cavitary areas of hemorrhage and necrosis. Two subcutaneous tumors were predominantly composed of expansile, blood-filled, cystic spaces lined by neoplastic cytotrophoblasts and occasionally contained medium to large trophoblasts. Trophoblasts and cytotrophoblasts were positive for pancytokeratin and cytokeratin 8/18, negative for alpha-fetoprotein, and contained intracytoplasmic Periodic acid-Schiff (PAS)-positive glycogen in all 4 tumors. In species with hemochorial placentation, migration of trophoblasts into maternal circulation with embolization to distant nonreproductive tissues occurs and may explain the unusual subcutaneous distribution of these 4 tumors. The 2 multiloculated paucicellular tumors may represent an early stage of neoplastic transformation. To the authors' knowledge, this is the first report characterizing choriocarcinomas in extrareproductive sites in rodents.

    View details for DOI 10.1177/03009858231203647

    View details for PubMedID 37830480

  • Deep Learning-Based Pipeline for Automatic Identification of Intestinal Regenerating Crypts in Mouse Histological Images. International journal of radiation oncology, biology, physics Fu, J., Jiang, H., Melemenidis, S., Viswanathan, V., Dutt, S., Lau, B., Soto, L. A., Manjappa, R., Skinner, L., Yu, S. J., Surucu, M., Graves, E. E., Casey, K., Rankin, E., Lu, W., Loo, B. W., Gu, X. 2023; 117 (2S): S117-S118

    Abstract

    PURPOSE/OBJECTIVE(S): A classical approach for evaluating normal tissue radiation response is to count the number of intestinal regenerating crypts in mouse histological images acquired after abdominal radiation. However, manual counting is time-consuming and subject to inter-observer variations. The goal of this study is to build a deep learning-based pipeline for automatically identifying intestinal regenerating crypts to facilitate high-throughput studies.MATERIALS/METHODS: Sixty-six healthy C57BL/6 female mice underwent 16 MeV whole abdominal electron irradiation. The small bowel was collected from each mouse 4 days post-irradiation, and 9 jejunal cross-sections from each were processed together in a single slide. The slides were stained with hematoxylin and eosin (H&E) and subsequently scanned (x20), providing one electronic histological image per mouse. Regenerating crypts, consisting of more than 10 basophilic crypt epithelial cells, were manually identified using point annotations in histological images. The pipeline was built to take the input of the image containing 9 cross sections and automatically identify the regenerating crypts on each cross section. It mainly consists of two components, cross section segmentation using intensity thresholding and morphological operations and crypt identification using a UNet. The dataset was randomly split into 46, 10, and 10 slide images for UNet training, validation, and testing. Each slide image was split into grid tiles with a voxel size of 200 * 200, and 40 * 40 square masks were placed with centers at manual point annotations on tiles with regenerating crypts. 5203/5198 tiles (w/wo crypt mask) were extracted to train UNet by minimizing dice loss. The mask probability map generated by the UNet was post-processed to identify the crypt position. Postprocessing hyperparameters were tuned using the validation dataset. The model accuracy was evaluated using the testing dataset by computing the mean absolute error (MAE) of the crypt number averaged across all cross sections.RESULTS: The number of regenerating crypts on testing cross sections ranges from 1 to 63. The testing cross-section-wise MAE achieved by the platform is 3.5±4.8 crypts. 81.25% of testing cross sections have absolute number differences less than or equal to 5 crypts.CONCLUSION: Our established deep learning-based pipeline can accurately count the number of regenerating crypts in mouse intestinal histological images. We have integrated it into an online platform that enables automatic crypt identification and allows users to interactively modify auto-identified crypt annotations. The acquired annotations from the platform will be used to finetune the deep learning model to achieve better identification performance.

    View details for DOI 10.1016/j.ijrobp.2023.06.451

    View details for PubMedID 37784305

  • Equivalent Dose Estimation in FLASH Irradiation with a Deep Learning Approach. International journal of radiation oncology, biology, physics Yang, Z., Fu, J., Melemenidis, S., Viswanathan, V., Dutt, S., Lau, B., Soto, L. A., Manjappa, R., Skinner, L., Yu, S. J., Surucu, M., Casey, K., Rankin, E., Lu, W., Jr, B. W., Gu, X. 2023; 117 (2S): e272

    Abstract

    PURPOSE/OBJECTIVE(S): Ultra-high dose rate (FLASH) irradiation has been reported to provide decreased normal tissue toxicity without compromising tumor control compared with conventional (CONV) irradiation. However, a comprehensive understanding of the FLASH biological effect requires precise quantification of radiobiology. The study is to explore whether deep learning (DL) can tackle the task. As a proof of concept, we investigate a DL model for estimating FLASH dose to its equivalent CONV dose.MATERIALS/METHODS: Healthy C57Bl/6 female mice underwent FLASH (200Gy/s; n = 43) or CONV (0.12Gy/s; n = 41) whole abdominal irradiation using 16 MeV electron beams with a dose escalation scheme of 5 groups (n = 8 or 9) at 1Gy increments: 12-16Gy FLASH, 11-15Gy CONV. 4 days post-irradiation, 9 jejunum cross-sections per mouse were H&E stained for histological analysis. Each cross-section image was processed to remove lumen background and oversampled into multiple large-scale and small-scale patches along jejunal circumference. In CONV dataset, we randomly selected the data of 32 mice (80%) for model training and the rest (20%) for model validation. A ResNet101-based DL model, pre-trained with an unsupervised contrastive learning scheme, was retrained with only CONV training set to estimate corresponding CONV dose. For comparison, a crypt counting (CC) approach was implemented by manually counting the number of regenerating crypts on each cross-section image. An exponential function of dose vs crypt number was fitted with the CONV training set and used for dose estimation on the testing set. Mean squared error (MSE) was used to assess the accuracy of DL and CC approaches in estimating dose levels in CONV irradiation. The validated DL model was applied to the FLASH set to project FLASH dose into corresponding CONV dose that results in equivalent biological response.RESULTS: The CONV dose estimated by DL and CC approaches and DL-estimated FLASH equivalent dose were summarized in Table 1. The DL model achieved an MSE of 0.21 Gy2 on CONV testing set compared with 0.32 Gy2 of the CC approach. FLASH equivalent dose estimated by DL model for 12, 13, 14, 15 and 16Gy were 12.16±0.40, 12.53±0.32, 12.72±0.24, 12.85±0.20 and 13.04±0.27 Sv, respectively.CONCLUSION: Our proposed DL model can accurately estimate the CONV dose based on histological images. The DL predictions of FLASH dataset demonstrate that FLASH may reduce normal tissue toxicity with a lower equivalent dose, especially at high irradiated dose levels. Our study indicates that deep learning can be potentially used to assess the equivalent dose of FLASH irradiation to normal tissue.

    View details for DOI 10.1016/j.ijrobp.2023.06.1241

    View details for PubMedID 37785029

  • An Online AI-Powered Interactive Histological Image Annotation Platform for Analyzing Intestinal Regenerating Crypts in Post-Irradiated Mice. International journal of radiation oncology, biology, physics Jiang, H., Fu, J., Melemenidis, S., Viswanathan, V., Dutt, S., Lau, B., Soto, L. A., Manjappa, R., Skinner, L., Yu, S. J., Surucu, M., Graves, E. E., Casey, K., Rankin, E., Lu, W., Loo, B. W., Gu, X. 2023; 117 (2S): e676

    Abstract

    PURPOSE/OBJECTIVE(S): The goal of this project is to build an online AI-powered interactive annotation platform to accurately and efficiently annotate intestinal regenerating crypts in histological images of mice after abdominal irradiation.MATERIALS/METHODS: The proposed platform is developed by the seamless integration of a front-end web client and a back-end server. Such client/server design allows the users to access the platform without software installation on local computers. Our front-end client is developed with SvelteJS + WebGL technology stack, allowing access from any common web browsers and enabling user interaction, such as image importing/visualization, interactive crypt annotating, and annotation saving/deleting. The back-end server is responsible for executing the tasks requested from the web client, for instance, image pre-processing, AI-based crypts automatic identification, and database management. The image preprocessing is designed to extract a single cross section image using morphological operations because multiple hematoxylin and eosin (H&E) stained jejunum cross sections from post-irradiated mice are scanned within one slide. The auto-crypt identification is powered by a trained and validated AI engine U-Net, classifying image grid tiles into two groups with and without regenerating crypts. The database is implemented with the self-contained SQLite to support recording and indexing the annotated grid tiles with regenerating crypts. The workflow for crypt analysis on this interactive platform has 5 steps: 1) manually import a whole H&E slide image; 2) auto-preprocess the slide by extracting single cross-section images; 3) auto-identify regenerating crypts with an AI engine; 4) interactively annotate (add, delete, modify) auto-identified crypt markers; 5) save and/or output the annotation to the database or the local drive.RESULTS: The performance of the developed interactive crypt analysis platform was evaluated in aspects of accuracy and efficiency. The AI-powered crypt auto-identification accuracy was assessed by computing the mean absolute error (MAE) on crypt number per cross section between manual and auto annotation using a testing dataset containing 80 cross sections. It achieved an MAE of 3.5±4.8 crypts per cross section, and 81.25% of the cross sections have no more than 5 crypts difference. The efficiency was assessed under two conditions with the server on the cloud and a local computer. It took about 2-3 minutes to finish the entire workflow on the cloud, while 1-2 minutes on the local by saving 1 minute on image uploading.CONCLUSION: The developed web client/server platform enables online automatic identification and interactive annotation of mice crypts in minutes. It is a convenient tool that allows accurate and efficient crypt analysis and can be extended for other histologic image analyses.

    View details for DOI 10.1016/j.ijrobp.2023.06.2130

    View details for PubMedID 37785993

  • Design of a mucin-selective protease for targeted degradation of cancer-associated mucins. Nature biotechnology Pedram, K., Shon, D. J., Tender, G. S., Mantuano, N. R., Northey, J. J., Metcalf, K. J., Wisnovsky, S. P., Riley, N. M., Forcina, G. C., Malaker, S. A., Kuo, A., George, B. M., Miller, C. L., Casey, K. M., Vilches-Moure, J. G., Ferracane, M. J., Weaver, V. M., Läubli, H., Bertozzi, C. R. 2023

    Abstract

    Targeted protein degradation is an emerging strategy for the elimination of classically undruggable proteins. Here, to expand the landscape of targetable substrates, we designed degraders that achieve substrate selectivity via recognition of a discrete peptide and glycan motif and achieve cell-type selectivity via antigen-driven cell-surface binding. We applied this approach to mucins, O-glycosylated proteins that drive cancer progression through biophysical and immunological mechanisms. Engineering of a bacterial mucin-selective protease yielded a variant for fusion to a cancer antigen-binding nanobody. The resulting conjugate selectively degraded mucins on cancer cells, promoted cell death in culture models of mucin-driven growth and survival, and reduced tumor growth in mouse models of breast cancer progression. This work establishes a blueprint for the development of biologics that degrade specific protein glycoforms on target cells.

    View details for DOI 10.1038/s41587-023-01840-6

    View details for PubMedID 37537499

    View details for PubMedCentralID 6031612

  • Subfunctionalized expression drives evolutionary retention of ribosomal protein paralogs Rps27 and Rps27l in vertebrates. eLife Xu, A. F., Molinuevo, R., Fazzari, E., Tom, H., Zhang, Z., Menendez, J., Casey, K. M., Ruggero, D., Hinck, L., Pritchard, J. K., Barna, M. 2023; 12

    Abstract

    The formation of paralogs through gene duplication is a core evolutionary process. For paralogs that encode components of protein complexes such as the ribosome, a central question is whether they encode functionally distinct proteins, or whether they exist to maintain appropriate total expression of equivalent proteins. Here, we systematically tested evolutionary models of paralog function using the ribosomal protein paralogs Rps27 (eS27) and Rps27l (eS27L) as a case study. Evolutionary analysis suggests that Rps27 and Rps27l likely arose during whole-genome duplication(s) in a common vertebrate ancestor. We show that Rps27 and Rps27l have inversely correlated mRNA abundance across mouse cell types, with the highest Rps27 in lymphocytes and the highest Rps27l in mammary alveolar cells and hepatocytes. By endogenously tagging the Rps27 and Rps27l proteins, we demonstrate that Rps27- and Rps27l-ribosomes associate preferentially with different transcripts. Furthermore, murine Rps27 and Rps27l loss-of-function alleles are homozygous lethal at different developmental stages. However, strikingly, expressing Rps27 protein from the endogenous Rps27l locus or vice versa completely rescues loss-of-function lethality and yields mice with no detectable deficits. Together, these findings suggest that Rps27 and Rps27l are evolutionarily retained because their subfunctionalized expression patterns render both genes necessary to achieve the requisite total expression of two equivalent proteins across cell types. Our work represents the most in-depth characterization of a mammalian ribosomal protein paralog to date and highlights the importance of considering both protein function and expression when investigating paralogs.

    View details for DOI 10.7554/eLife.78695

    View details for PubMedID 37306301

  • Lineage-Specific Induced Pluripotent Stem Cell-Derived Smooth Muscle Cell Modeling Predicts Integrin Alpha-V Antagonism Reduces Aortic Root Aneurysm Formation in Marfan Syndrome Mice. Arteriosclerosis, thrombosis, and vascular biology Nakamura, K., Dalal, A. R., Yokoyama, N., Pedroza, A. J., Kusadokoro, S., Mitchel, O., Gilles, C., Masoudian, B., Leipzig, M., Casey, K. M., Hiesinger, W., Uchida, T., Fischbein, M. P. 2023

    Abstract

    To delineate the effects of integrin αv signaling in Marfan syndrome (MFS) and examine the potential efficacy of integrin αv blockade as a therapeutic strategy for MFS aneurysms.Induced pluripotent stem cells were differentiated into aortic smooth muscle cells (SMCs) of the second heart field (SHF) and neural crest lineages, enabling in vitro modeling of thoracic aortic aneurysm in MFS. Fbn1C1039G/+ MFS mice treated with integrin αv antagonist (GLPG0187) confirmed the pathological role of integrin αv on aneurysm formation.Induced pluripotent stem cell-derived MFS SHF SMCs overexpress integrin αv relative to MFS neural crest and healthy control SHF cells. Furthermore, downstream targets of integrin αv (FAK [focal adhesion kinase]/AktThr308/mTORC1 [mechanistic target of rapamycin complex 1]) were activated, especially in MFS SHF. Treatment GLPG0187 reduced p-FAK/p-AktThr308/mTORC1 activity in MFS SHF back to control SHF levels. Functionally, MFS SHF SMCs had increased proliferation and migration compared to MFS neural crest and control SMCs, which was then inhibited by GLPG0187 treatment. In the Fbn1C1039G/+ MFS mouse model, integrin αv, p-AktThr308, and downstream targets of mTORC1 proteins were elevated in the aortic root/ascending segment compared to littermate wild-type control. Mice treated with GLPG0187 (age 6-14 weeks) resulted in reduced aneurysm growth, elastin fragmentation, and normalization of the FAK/AktThr308/mTORC1 pathway. GLPG0187 treatment reduced the amount and severity of SMC modulation assessed by single-cell RNA sequencing.The integrin αv-FAK-AktThr308 signaling pathway is activated in induced pluripotent stem cell SMCs from MFS patients, specifically from the SHF lineage. Mechanistically, this signaling pathway promotes SMC proliferation and migration in vitro. As biological proof of concept, GLPG0187 treatment slowed aneurysm growth and p-AktThr308 signaling in Fbn1C1039G/+ mice. Integrin αv blockade via GLPG0187 may be a promising therapeutic approach to inhibit MFS aneurysmal growth.

    View details for DOI 10.1161/ATVBAHA.122.318448

    View details for PubMedID 37078287

  • An optimized bioluminescent substrate for non-invasive imaging in the brain. Nature chemical biology Su, Y., Walker, J. R., Hall, M. P., Klein, M. A., Wu, X., Encell, L. P., Casey, K. M., Liu, L. X., Hong, G., Lin, M. Z., Kirkland, T. A. 2023

    Abstract

    Bioluminescence imaging (BLI) allows non-invasive visualization of cells and biochemical events in vivo and thus has become an indispensable technique in biomedical research. However, BLI in the central nervous system remains challenging because luciferases show relatively poor performance in the brain with existing substrates. Here, we report the discovery of a NanoLuc substrate with improved brain performance, cephalofurimazine (CFz). CFz paired with Antares luciferase produces greater than 20-fold more signal from the brain than the standard combination of D-luciferin with firefly luciferase. At standard doses, Antares-CFz matches AkaLuc-AkaLumine/TokeOni in brightness, while occasional higher dosing of CFz can be performed to obtain threefold more signal. CFz should allow the growing number of NanoLuc-based indicators to be applied to the brain with high sensitivity. Using CFz, we achieve video-rate non-invasive imaging of Antares in brains of freely moving mice and demonstrate non-invasive calcium imaging of sensory-evoked activity in genetically defined neurons.

    View details for DOI 10.1038/s41589-023-01265-x

    View details for PubMedID 36759751

  • Brain Permeable Bioluminescent Substrate for NanoLuc based Reporters Walker, J. R., Su, Y., Wu, X., Casey, K., Hong, G., Kirkland, T. A., Lin, M. Z. AMER SOC CELL BIOLOGY. 2023: 662
  • Canagliflozin retards age-related lesions in heart, kidney, liver, and adrenal gland in genetically heterogenous male mice. GeroScience Snyder, J. M., Casey, K. M., Galecki, A., Harrison, D. E., Jayarathne, H., Kumar, N., Macchiarini, F., Rosenthal, N., Sadagurski, M., Salmon, A. B., Strong, R., Miller, R. A., Ladiges, W. 2022

    Abstract

    Canagliflozin (Cana), a clinically important anti-diabetes drug, leads to a 14% increase in median lifespan and a 9% increase in the 90th percentile age when given to genetically heterogeneous male mice from 7months of age, but does not increase lifespan in female mice. A histopathological study was conducted on 22-month-old mice to see if Cana retarded diverse forms of age-dependent pathology. This agent was found to diminish incidence or severity, in male mice only, of cardiomyopathy, glomerulonephropathy, arteriosclerosis, hepatic microvesicular cytoplasmic vacuolation (lipidosis), and adrenal cortical neoplasms. Protection against atrophy of the exocrine pancreas was seen in both males and females. Thus, the extension of lifespan in Cana-treated male mice, which is likely to reflect host- or tumor-mediated delay in lethal neoplasms, is accompanied by parallel retardation of lesions, in multiple tissues, that seldom if ever lead to death in these mice. Canagliflozin thus can be considered a drug that acts to slow the aging process and should be evaluated for potential protective effects against many other late-life conditions.

    View details for DOI 10.1007/s11357-022-00641-0

    View details for PubMedID 35974129

  • A novel photosynthetic biologic topical gel for enhanced localized hyperoxygenation augments wound healing in peripheral artery disease. Scientific reports Zhu, Y., Jung, J., Anilkumar, S., Ethiraj, S., Madira, S., Tran, N. A., Mullis, D. M., Casey, K. M., Walsh, S. K., Stark, C. J., Venkatesh, A., Boakye, A., Wang, H., Woo, Y. J. 2022; 12 (1): 10028

    Abstract

    Peripheral artery disease and the associated ischemic wounds are substantial causes of global morbidity and mortality, affecting over 200 million people worldwide. Although advancements have been made in preventive, pharmacologic, and surgical strategies to treat this disease, ischemic wounds, a consequence of end-stage peripheral artery disease, remain a significant clinical and economic challenge. Synechococcus elongatus is a cyanobacterium that grows photoautotrophically and converts carbon dioxide and water into oxygen. We present a novel topical biologic gel containing S. elongatus that provides oxygen via photosynthesis to augment wound healing by rescuing ischemic tissues caused by peripheral artery disease. By using light rather than blood as a source of energy, our novel topical therapy significantly accelerated wound healing in two rodent ischemic wound models. This novel topical gel can be directly translated to clinical practice by using a localized, portable light source without interfering with patients' daily activities, demonstrating potential to generate a paradigm shift in treating ischemic wounds from peripheral artery disease. Its novelty, low production cost, and ease of clinical translatability can potentially impact the clinical care for millions of patients suffering from peripheral arterial disease.

    View details for DOI 10.1038/s41598-022-14085-1

    View details for PubMedID 35705660

  • Degenerative Osteoarthropathy in Laboratory Housed Xenopus (Silurana) tropicalis. Comparative medicine Zhang, M., Wilson, S. S., Casey, K. M., Thomson, P. E., Zlatow, A. L., Langlois, V. S., Green, S. L. 1800; 71 (6): 512-520

    Abstract

    In this case study, 15 adult laboratory Xenopus (Silurana) tropicalis (7 adult males and 8 adult females) were examined for nodular enlargements of the clawed digits (digits 0, I, II, and III) on the hind feet. Radiographs showed smoothly margined, rounded, peripherally mineralized lesions arising from the distal phalanges of digits 0-III with osteoproductive and osteolytic components in all frogs. Micro computed tomography (microCT) scans further revealed interphalangeal (IP), metacarpophalangeal (MCP), and metatarsophalangeal (MTP) joint osteoarthritis characterized by periarticular new bone formation, rounded mineral foci both peripherally and centrally within the joints, and more rarely, linear mineralization palmar/plantar to the joints in the flexor tendons. In the nonclawed digits, the shape of the distal phalanx was variably distorted and both subluxation and malangulation of IP joints were identified. Histologically, nodules corresponded to a peripheral rim of mature cortical bone surrounding central adipose tissue, scattered hematopoietic elements, and residual bone of the distal phalanx. Occasionally, the peripheral rim of cortical bone extended proximally to encompass the distal aspect of adjacent phalanx. MCP, MTP and IP joint spaces of most digits exhibited widespread osteoarthritis characterized by periarticular cartilaginous or osseous metaplasia, bony remodeling, and less frequently, granulomatous osteomyelitis. Nutritional analyses of the feed did not indicate imbalances nor were the lesions consistent with metabolic bone disease. The exact etiopathogenesis of these lesions is unknown; however, we hypothesize that the osteoarthritic changes are due to a combination of the frogs' mature age, the unique structure of the Xenopus spp. claw, genetics and biomechanical forces on the digits and distal phalanges of the hind feet.

    View details for DOI 10.30802/AALAS-CM-21-000061

    View details for PubMedID 34794532

  • Fibrous Osteodystrophy, Chronic Renal Disease, and Uterine Adenocarcinoma in Aged Gray Mouse Lemurs (Microcebus murinus). Comparative medicine Casey, K. M., Karanewsky, C. J., Pendleton, J. L., Krasnow, M. R., Albertelli, M. A. 2021; 71 (3): 256-266

    Abstract

    The gray mouse lemur (Microcebus murinus, GML) is a nocturnal, arboreal, prosimian primate that is native to Madagascar. Captive breeding colonies of GMLs have been established primarily for noninvasive studies on questions related to circadian rhythms and metabolism. GMLs are increasingly considered to be a strong translational model for neurocognitive aging due to overlapping histopathologic features shared with aged humans. However, little information is available describing the clinical presentations, naturally occurring diseases, and histopathology of aged GMLs. In our colony, a 9 y-old, male, GML was euthanized after sudden onset of weakness, lethargy, and tibial fracture. Evaluation of this animal revealed widespread fibrous osteodystrophy (FOD) of the mandible, maxilla, cranium, appendicular, and vertebral bones. FOD and systemic metastatic mineralization were attributed to underlying chronic renal disease. Findings in this GML prompted periodic colony-wide serum biochemical screenings for azotemia and electrolyte abnormalities. Subsequently, 3 additional GMLs (2 females and 1 male) were euthanized due to varying clinical and serum biochemical presentations. Common to all 4 animals were FOD, chronic renal disease, uterine adenocarcinoma (females only), cataracts, and osteoarthritis. This case study highlights the concurrent clinical and histopathologic abnormalities that are relevant to use of GMLs in the expanding field of aging research.

    View details for DOI 10.30802/AALAS-CM-20-000078

    View details for PubMedID 34082858

  • Antitumor effects of iPSC-based cancer vaccine in pancreatic cancer. Stem cell reports Ouyang, X., Liu, Y., Zhou, Y., Guo, J., Wei, T., Liu, C., Lee, B., Chen, B., Zhang, A., Casey, K. M., Wang, L., Kooreman, N. G., Habtezion, A., Engleman, E. G., Wu, J. C. 2021

    Abstract

    Induced pluripotent stem cells (iPSCs) and cancer cells share cellular similarities and transcriptomic profiles. Here, we show that an iPSC-based cancer vaccine, comprised of autologous iPSCs and CpG, stimulated cytotoxic antitumor CD8+ Tcell effector and memory responses, induced cancer-specific humoral immune responses, reduced immunosuppressive CD4+ T regulatory cells, and prevented tumor formation in 75% of pancreatic ductal adenocarcinoma (PDAC) mice. We demonstrate that shared gene expression profiles of "iPSC-cancer signature genes" and others are overexpressed in mouse and human iPSC lines, PDAC cells, and multiple human solid tumor types compared with normal tissues. These results support further studies of iPSC vaccination in PDAC in preclinical and clinical models and in other cancer types that have low mutational burdens.

    View details for DOI 10.1016/j.stemcr.2021.04.004

    View details for PubMedID 33961792

  • Management of Morbidity and Mortality in a New Zealand White Rabbit Model of Steroid-Induced Osteonecrosis of the Femoral Head COMPARATIVE MEDICINE Casey, K. M., Gore, F., Vilches-Moure, J. G., Maruyama, M., Goodman, S. B., Yang, Y., Baker, S. W. 2021; 71 (1): 86–98

    Abstract

    Steroid-induced osteonecrosis of the femoral head (SONFH) is a condition documented in humans and animals exposed to chronic steroid administration. The rabbit has become a preferred animal model for investigating the pathogenesis and treatment of SONFH due to its shared femoral vascular anatomy with human patients, relative size of the femoral head, and general fecundity. However, morbidity and mortality are frequent during the steroid induction period, prior to surgical manipulation. These problems are poorly reported and inadequately described in the literature. In this study, we report the clinical, gross, and histopathologic findings of New Zealand white (NZW) rabbits undergoing the steroid induction phase of the SONFH model. Severe weight loss (>30%), lipemia, hypercholesterolemia, hyperglycemia, and elevations in ALT and AST were consistent findings across all rabbits, although these changes did not differentiate asymptomatic rabbits from those that became clinically symptomatic or died. Euthanized and spontaneously deceased rabbits exhibited hepatomegaly, hepatic lipidosis/glycogenosis, and hepatocellular necrosis, in addition to a lipid-rich and proteinaceous thoracic effusion. A subset of rabbits developed opportunistic pulmonary infections with Bordetella bronchiseptica and Escherichia coli and small intestine infections with Lawsonia intracellularis superimposed on hepatic and thoracic disease. Together, these findings allowed us to establish a clinical decision-making flowchart that reduced morbidities and mortalities in a subsequent cohort of SONFH rabbits. Recognition of these model-associated morbidities is critical for providing optimal clinical care during the disease induction phase of SONFH.

    View details for DOI 10.30802/AALAS-CM-20-000071

    View details for Web of Science ID 000620257900005

    View details for PubMedID 33500020

    View details for PubMedCentralID PMC7898173

  • Mitochondrial copper depletion suppresses triple-negative breast cancer in mice. Nature biotechnology Cui, L., Gouw, A. M., LaGory, E. L., Guo, S., Attarwala, N., Tang, Y., Qi, J., Chen, Y., Gao, Z., Casey, K. M., Bazhin, A. A., Chen, M., Hu, L., Xie, J., Fang, M., Zhang, C., Zhu, Q., Wang, Z., Giaccia, A. J., Gambhir, S. S., Zhu, W., Felsher, D. W., Pegram, M. D., Goun, E. A., Le, A., Rao, J. 2020

    Abstract

    Depletion of mitochondrial copper, which shifts metabolism from respiration to glycolysis and reduces energy production, is known to be effective against cancer types that depend on oxidative phosphorylation. However, existing copper chelators are too toxic or ineffective for cancer treatment. Here we develop a safe, mitochondria-targeted, copper-depleting nanoparticle (CDN) and test it against triple-negative breast cancer (TNBC). We show that CDNs decrease oxygen consumption and oxidative phosphorylation, cause a metabolic switch to glycolysis and reduce ATP production in TNBC cells. This energy deficiency, together with compromised mitochondrial membrane potential and elevated oxidative stress, results in apoptosis. CDNs should be less toxic than existing copper chelators because they favorably deprive copper in the mitochondria in cancer cells instead of systemic depletion. Indeed, we demonstrate low toxicity of CDNs in healthy mice. In three mouse models of TNBC, CDN administration inhibits tumor growth and substantially improves survival. The efficacy and safety of CDNs suggest the potential clinical relevance of this approach.

    View details for DOI 10.1038/s41587-020-0707-9

    View details for PubMedID 33077961

  • FLASH irradiation enhances the therapeutic index of abdominal radiotherapy in mice Natarajan, S., Levy, K., Wang, J., Chow, S., Eggold, J., Loo, P., Manjappa, R., Lartey, F. M., Schuler, E., Skinner, L., Rafat, M., Ko, R., Kim, A., Al Rawi, D., von Eyben, R., Dorigo, O., Casey, K. M., Graves, E. E., Bush, K., Yu, A. S., Koong, A. C., Maxim, P. G., Loo, B. W., Rankin, E. B. AMER ASSOC CANCER RESEARCH. 2020
  • Novel NanoLuc substrates enable bright two-population bioluminescence imaging in animals. Nature methods Su, Y., Walker, J. R., Park, Y., Smith, T. P., Liu, L. X., Hall, M. P., Labanieh, L., Hurst, R., Wang, D. C., Encell, L. P., Kim, N., Zhang, F., Kay, M. A., Casey, K. M., Majzner, R. G., Cochran, J. R., Mackall, C. L., Kirkland, T. A., Lin, M. Z. 2020

    Abstract

    Sensitive detection of two biological events in vivo has long been a goal in bioluminescence imaging. Antares, a fusion of the luciferase NanoLuc to the orange fluorescent protein CyOFP, has emerged as a bright bioluminescent reporter with orthogonal substrate specificity to firefly luciferase (FLuc) and its derivatives such as AkaLuc. However, the brightness of Antares in mice is limited by the poor solubility and bioavailability of the NanoLuc substrate furimazine. Here, we report a new substrate, hydrofurimazine, whose enhanced aqueous solubility allows delivery of higher doses to mice. In the liver, Antares with hydrofurimazine exhibited similar brightness to AkaLuc with its substrate AkaLumine. Further chemical exploration generated a second substrate, fluorofurimazine, with even higher brightness in vivo. We used Antares with fluorofurimazine to track tumor size and AkaLuc with AkaLumine to visualize CAR-T cells within the same mice, demonstrating the ability to perform two-population imaging with these two luciferase systems.

    View details for DOI 10.1038/s41592-020-0889-6

    View details for PubMedID 32661427

  • The Stability and Efficacy of Tricaine Methanesulfonate (MS222) Solution After Long-Term Storage JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE Katz, E. M., Chu, D. K., Casey, K. M., Jampachaisri, K., Felt, S. A., Pacharinsak, C. 2020; 59 (4): 393–400

    Abstract

    Tricaine methanesulfonate (MS222) is widely used for the anesthesia and euthanasia of laboratory zebrafish. Fresh solutions have been recommended for each use; however, researchers often mix and store concentrated stock solutions for convenience and to reduce occupational exposure and environmental waste. While this is common practice, published guidelines are often inconsistent. Thus, the objective of this study was to evaluate the stability and anesthetic efficacy of MS222 after long-term storage and to develop specific storage parameters. Stock solutions (100 mg/mL MS222) were mixed and stored in amber jars at 4 °C and -20 °C for 2- and 6-mo. Stability of the solutions was analyzed using liquid chromatography-ion trapmass spectrometry and compared with fresh MS222. Fifty adult (30 male, 20 female) wildtype AB zebrafish (Danio rerio) wererandomly anesthetized with 150 mg/L of one of the following MS222 solutions to evaluate anesthetic efficacy: 1) freshly prepared(0m); 2) 2 mo at 4 °C (2m4); 3) 2 mo at -20 °C (2m-20); 4) 6 mo at 4 °C (6m4); 5) 6 mo at -20 °C (6m-20). Time to cessation of swimming, loss of equilibrium, lack of response to von Frey (VF) stimulation, return of equilibrium, and resumption of swimming were compared between groups. Two fish from each group were euthanized at 24-h and 2-wk after anesthesia, and histopathology was performed. All solutions were determined to be stable under all storage conditions. No clinically significant differences were observed between the fresh and stored stock groups during anesthetic testing. No evidence ofanesthetic-related histologic changes were noted in the gills, skin, kidneys, muscle, and central nervous system. Hepatic megalocytosis and a reduction in hepatic vacuolation were seen to varying degrees across all groups, but did not follow a treatment-related trend. Therefore, 100 mg/mL solutions of MS222 can be stored in amber jars at 4 °C or -20 °C for 6 mo and still used to effectively anesthetize zebrafish.

    View details for DOI 10.30802/AALAS-JAALAS-19-000067

    View details for Web of Science ID 000569144100009

    View details for PubMedID 32532365

    View details for PubMedCentralID PMC7338872

  • Premature thymic involution and oropharyngeal blistering cause early lethality in generalized severe junctional epidermolysis bullosa Yenamandra, V. K., Dolorito, J., Gurevitch, I., Godoy, E., Casey, K., Marinkovich, M. P. ELSEVIER SCIENCE INC. 2020: S35
  • Tumor shedding and metastatic progression after tumor excision in patient-derived orthotopic xenograft models of triple-negative breast cancer. Clinical & experimental metastasis Razmara, A. M., Sollier, E., Kisirkoi, G. N., Baker, S. W., Bellon, M. B., McMillan, A., Lemaire, C. A., Ramani, V. C., Jeffrey, S. S., Casey, K. M. 2020

    Abstract

    Patient-derived orthotopic xenograft (PDOX) models have been verified as a useful method for studying human cancers in mice. Previous studies on the extent of metastases in these models have been limited by the necessity of welfare euthanasia (primary tumors reaching threshold size), at which point metastases may only be micrometers in diameter, few in number, and solely identified by step-sectioning of formalin-fixed paraffin-embedded tissue. These small micro-metastases are less suitable for many downstream molecular analyses than macro-metastases. Resection of the primary tumor by survival surgery has been proven to allow further time for metastases to grow. Although PDOX models of triple-negative breast cancer (TNBC) shed circulating tumor cells (CTCs) into the bloodstream and metastasize, similar to human TNBC, little data has been collected in these TNBC PDOX models regarding the association between CTC characteristics and distant metastasis following excision of the primary tumor xenograft. This study assembles a timeline of PDOX tumor shedding and metastatic tumor progression before and after tumor excision surgery. We report the ability to use tumorectomies to increase the lifespan of TNBC PDOX models with the potential to obtain larger metastases. CTC clusters and CTCs expressing a mesenchymal marker (vimentin) were associated with metastatic burden in lung and liver. The data collected through these experiments will guide the further use of PDOX models in studying metastatic TNBC.

    View details for DOI 10.1007/s10585-020-10033-3

    View details for PubMedID 32335861

  • Histologic safety of transcranial focused ultrasound neuromodulation and magnetic resonance acoustic radiation force imaging in rhesus macaques and sheep. Brain stimulation Gaur, P., Casey, K. M., Kubanek, J., Li, N., Mohammadjavadi, M., Saenz, Y., Glover, G. H., Bouley, D. M., Pauly, K. B. 2020; 13 (3): 804–14

    Abstract

    BACKGROUND: Neuromodulation by transcranial focused ultrasound (FUS) offers the potential to non-invasively treat specific brain regions, with treatment location verified by magnetic resonance acoustic radiation force imaging (MR-ARFI).OBJECTIVE: To investigate the safety of these methods prior to widespread clinical use, we report histologic findings in two large animal models following FUS neuromodulation and MR-ARFI.METHODS: Two rhesus macaques and thirteen Dorset sheep were studied. FUS neuromodulation was targeted to the primary visual cortex in rhesus macaques and to subcortical locations, verified by MR-ARFI, in eleven sheep. Both rhesus macaques and five sheep received a single FUS session, whereas six sheep received repeated sessions three to six days apart. The remaining two control sheep did not receive ultrasound but otherwise underwent the same anesthetic and MRI procedures as the eleven experimental sheep. Hematoxylin and eosin-stained sections of brain tissue (harvested zero to eleven days following FUS) were evaluated for tissue damage at FUS and control locations as well as tissue within the path of the FUS beam. TUNEL staining was used to evaluate for the presence of apoptosis in sheep receiving high dose FUS.RESULTS: No FUS-related pre-mortem histologic findings were observed in the rhesus macaques or in any of the examined sheep. Extravascular red blood cells (RBCs) were present within the meninges of all sheep, regardless of treatment group. Similarly, small aggregates of perivascular RBCs were rarely noted in non-target regions of neural parenchyma of FUS-treated (8/11) and untreated (2/2) sheep. However, no concurrent histologic abnormalities were observed, consistent with RBC extravasation occurring as post-mortem artifact following brain extraction. Sheep within the high dose FUS group were TUNEL-negative at the targeted site of FUS.CONCLUSIONS: The absence of FUS-related histologic findings suggests that the neuromodulation and MR-ARFI protocols evaluated do not cause tissue damage.

    View details for DOI 10.1016/j.brs.2020.02.017

    View details for PubMedID 32289711

  • AND-gate contrast agents for enhanced fluorescence-guided surgery. Nature biomedical engineering Widen, J. C., Tholen, M. n., Yim, J. J., Antaris, A. n., Casey, K. M., Rogalla, S. n., Klaassen, A. n., Sorger, J. n., Bogyo, M. n. 2020

    Abstract

    Surgical resection of tumours requires precisely locating and defining the margins between lesions and normal tissue. However, this is made difficult by irregular margin borders. Although molecularly targeted optical contrast agents can be used to define tumour margins during surgery in real time, the selectivity of the contrast agents is often limited by the target being expressed in both healthy and tumour tissues. Here, we show that AND-gate optical imaging probes that require the processing of two substrates by multiple tumour-specific enzymes produce a fluorescent signal with significantly improved specificity and sensitivity to tumour tissue. We evaluated the performance of the probes in mouse models of mammary tumours and of metastatic lung cancer, as well as during fluorescence-guided robotic surgery. Imaging probes that rely on multivariate activation to selectively target complex patterns of enzymatic activity should be useful in disease detection, treatment and monitoring.

    View details for DOI 10.1038/s41551-020-00616-6

    View details for PubMedID 32989286

  • Multi-modal imaging reveals differential brain volumetric, biochemical, and white matter fiber responsivity to repeated intermittent ethanol vapor exposure in male and female rats. Neuropharmacology Zahr, N. M., Lenart, A. M., Karpf, J. A., Casey, K. M., Pohl, K. M., Sullivan, E. V., Pfefferbaum, A. n. 2020: 108066

    Abstract

    A generally accepted framework derived predominately from animal models asserts that repeated cycles of chronic intermittent ethanol (EtOH; CIE) exposure cause progressive brain adaptations associated with anxiety and stress that promote voluntary drinking, alcohol dependence, and further brain changes that contribute to the pathogenesis of alcoholism. The current study used CIE exposure via vapor chambers to test the hypothesis that repeated episodes of withdrawals from chronic EtOH would be associated with accrual of brain damage as quantified using in vivo magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), and MR spectroscopy (MRS). The initial study group included 16 male (∼325g) and 16 female (∼215g) wild-type Wistar rats exposed to 3 cycles of 1-month in vapor chambers + 1 week of abstinence. Half of each group (n = 8) was given vaporized EtOH to blood alcohol levels approaching 250 mg/dL. Blood and behavior markers were also quantified. There was no evidence for dependence (i.e., increased voluntary EtOH consumption), increased anxiety, or an accumulation of pathology. Neuroimaging brain responses to exposure included increased cerebrospinal fluid (CSF) and decreased gray matter volumes, increased Choline/Creatine, and reduced fimbria-fornix fractional anisotropy (FA) with recovery seen after one or more cycles and effects in female more prominent than in male rats. These results show transient brain integrity changes in response to CIE sufficient to induce acute withdrawal but without evidence for cumulative or escalating damage. Together, the current study suggests that nutrition, age, and sex should be considered when modeling human alcoholism.

    View details for DOI 10.1016/j.neuropharm.2020.108066

    View details for PubMedID 32240669

  • FLASH Irradiation Results in Reduced Severe Skin Toxicity Compared to Conventional-Dose-Rate Irradiation. Radiation research Soto, L. A., Casey, K. M., Wang, J. n., Blaney, A. n., Manjappa, R. n., Breitkreutz, D. n., Skinner, L. n., Dutt, S. n., Ko, R. B., Bush, K. n., Yu, A. S., Melemenidis, S. n., Strober, S. n., Englemann, E. n., Maxim, P. G., Graves, E. E., Loo, B. W. 2020

    Abstract

    Radiation therapy, along with surgery and chemotherapy, is one of the main treatments for cancer. While radiotherapy is highly effective in the treatment of localized tumors, its main limitation is its toxicity to normal tissue. Previous preclinical studies have reported that ultra-high dose-rate (FLASH) irradiation results in reduced toxicity to normal tissues while controlling tumor growth to a similar extent relative to conventional-dose-rate (CONV) irradiation. To our knowledge this is the first report of a dose-response study in mice comparing the effect of FLASH irradiation vs. CONV irradiation on skin toxicity. We found that FLASH irradiation results in both a lower incidence and lower severity of skin ulceration than CONV irradiation 8 weeks after single-fraction hemithoracic irradiation at high doses (30 and 40 Gy). Survival was also higher after FLASH hemithoracic irradiation (median survival >180 days at doses of 30 and 40 Gy) compared to CONV irradiation (median survival 100 and 52 days at 30 and 40 Gy, respectively). No ulceration was observed at doses 20 Gy or below in either FLASH or CONV. These results suggest a shifting of the dose-response curve for radiation-induced skin ulceration to the right for FLASH, compared to CONV irradiation, suggesting the potential for an enhanced therapeutic index for radiation therapy of cancer.

    View details for DOI 10.1667/RADE-20-00090

    View details for PubMedID 32853385

  • Abdominal FLASH irradiation reduces radiation-induced gastrointestinal toxicity for the treatment of ovarian cancer in mice. Scientific reports Levy, K. n., Natarajan, S. n., Wang, J. n., Chow, S. n., Eggold, J. T., Loo, P. E., Manjappa, R. n., Melemenidis, S. n., Lartey, F. M., Schüler, E. n., Skinner, L. n., Rafat, M. n., Ko, R. n., Kim, A. n., H Al-Rawi, D. n., von Eyben, R. n., Dorigo, O. n., Casey, K. M., Graves, E. E., Bush, K. n., Yu, A. S., Koong, A. C., Maxim, P. G., Loo, B. W., Rankin, E. B. 2020; 10 (1): 21600

    Abstract

    Radiation therapy is the most effective cytotoxic therapy for localized tumors. However, normal tissue toxicity limits the radiation dose and the curative potential of radiation therapy when treating larger target volumes. In particular, the highly radiosensitive intestine limits the use of radiation for patients with intra-abdominal tumors. In metastatic ovarian cancer, total abdominal irradiation (TAI) was used as an effective postsurgical adjuvant therapy in the management of abdominal metastases. However, TAI fell out of favor due to high toxicity of the intestine. Here we utilized an innovative preclinical irradiation platform to compare the safety and efficacy of TAI ultra-high dose rate FLASH irradiation to conventional dose rate (CONV) irradiation in mice. We demonstrate that single high dose TAI-FLASH produced less mortality from gastrointestinal syndrome, spared gut function and epithelial integrity, and spared cell death in crypt base columnar cells compared to TAI-CONV irradiation. Importantly, TAI-FLASH and TAI-CONV irradiation had similar efficacy in reducing tumor burden while improving intestinal function in a preclinical model of ovarian cancer metastasis. These findings suggest that FLASH irradiation may be an effective strategy to enhance the therapeutic index of abdominal radiotherapy, with potential application to metastatic ovarian cancer.

    View details for DOI 10.1038/s41598-020-78017-7

    View details for PubMedID 33303827

  • Biodegradable fluorescent nanoparticles for endoscopic detection of colorectal carcinogenesis. Advanced functional materials Rogalla, S., Flisikowski, K., Gorpas, D., Mayer, A. T., Flisikowska, T., Mandella, M. J., Ma, X., Casey, K. M., Felt, S. A., Saur, D., Ntziachristos, V., Schnieke, A., Contag, C. H., Gambhir, S. S., Harmsen, S. 2019; 29 (51)

    Abstract

    Early and comprehensive endoscopic detection of colonic dysplasia - the most clinically significant precursor lesion to colorectal adenocarcinoma - provides an opportunity for timely, minimally-invasive intervention to prevent malignant transformation. Here, the development and evaluation of biodegradable near-infrared fluorescent silica nanoparticles (FSN) is described that have the potential to improve adenoma detection during fluorescence-assisted white-light colonoscopic surveillance in rodent and human-scale models of colorectal carcinogenesis. FSNs are biodegradable (t1/2 of 2.7 weeks), well-tolerated, and enable detection and delineation of adenomas as small as 0.5 mm2 with high tumor-to-background ratios. Furthermore, in the human-scale, APC 1311/+ porcine model, the clinical feasibility and benefit of using FSN-guided detection of colorectal adenomas using video-rate fluorescence-assisted white-light endoscopy is demonstrated. Since nanoparticles of similar size (e.g., 100-150-nm) or composition (i.e., silica, silica/gold hybrid) have already been successfully translated to the clinic, and, clinical fluorescent/white light endoscopy systems are becoming more readily available, there is a viable path towards clinical translation of the proposed strategy for early colorectal cancer detection and prevention in high-risk patients.

    View details for DOI 10.1002/adfm.201904992

    View details for PubMedID 33041743

    View details for PubMedCentralID PMC7546531

  • Biodegradable Fluorescent Nanoparticles for Endoscopic Detection of Colorectal Carcinogenesis ADVANCED FUNCTIONAL MATERIALS Rogalla, S., Flisikowski, K., Gorpas, D., Mayer, A. T., Flisikowska, T., Mandella, M. J., Ma, X., Casey, K. M., Felt, S. A., Saur, D., Ntziachristos, V., Schnieke, A., Contag, C. H., Gambhir, S. S., Harmsen, S. 2019; 29 (51)
  • EVALUATION OF DYNAMIN 2 (DNM2) AS A THERAPEUTIC TARGET IN LEPTOMENINGEAL METASTATIC DISEASE Chernikova, S., Polyak, D., Deng, J., Tsau, S., Casey, K., Johnson, E., Bhambhvani, H., Khoeur, L., Stanley, G., Tran, K., Connolly, I., Joyce, A., Li, Y., von Eyben, R., Nagpal, S., Gephart, M. OXFORD UNIV PRESS INC. 2019: 57
  • Investigating circulating tumor cells and distant metastases in patient-derived orthotopic xenograft models of triple-negative breast cancer. Breast cancer research : BCR Ramani, V. C., Lemaire, C. A., Triboulet, M., Casey, K. M., Heirich, K., Renier, C., Vilches-Moure, J. G., Gupta, R., Razmara, A. M., Zhang, H., Sledge, G. W., Sollier, E., Jeffrey, S. S. 2019; 21 (1): 98

    Abstract

    BACKGROUND: Circulating tumor cells (CTCs) represent a temporal "snapshot" of a patient's cancer and changes that occur during disease evolution. There is an extensive literature studying CTCs in breast cancer patients, and particularly in those with metastatic disease. In parallel, there is an increasing use of patient-derived models in preclinical investigations of human cancers. Yet studies are still limited demonstrating CTC shedding and metastasis formation in patient-derived models of breast cancer.METHODS: We used seven patient-derived orthotopic xenograft (PDOX) models generated from triple-negative breast cancer (TNBC) patients to study CTCs and distant metastases. Tumor fragments from PDOX tissue from each of the seven models were implanted into 57 NOD scid gamma (NSG) mice, and tumor growth and volume were monitored. Human CTC capture from mouse blood was first optimized on the marker-agnostic Vortex CTC isolation platform, and whole blood was processed from 37 PDOX tumor-bearing mice.RESULTS: Staining and imaging revealed the presence of CTCs in 32/37 (86%). The total number of CTCs varied between different PDOX tumor models and between individual mice bearing the same PDOX tumors. CTCs were heterogeneous and showed cytokeratin (CK) positive, vimentin (VIM) positive, and mixed CK/VIM phenotypes. Metastases were detected in the lung (20/57, 35%), liver (7/57, 12%), and brain (1/57, less than 2%). The seven different PDOX tumor models displayed varying degrees of metastatic potential, including one TNBC PDOX tumor model that failed to generate any detectable metastases (0/8 mice) despite having CTCs present in the blood of 5/5 tested, suggesting that CTCs from this particular PDOX tumor model may typify metastatic inefficiency.CONCLUSION: PDOX tumor models that shed CTCs and develop distant metastases represent an important tool for investigating TNBC.

    View details for DOI 10.1186/s13058-019-1182-4

    View details for PubMedID 31462307

  • Novel NanoLuc substrates enable bright and sustained bioluminescence imaging in animals Walker, J., Park, Y., Smith, T., Wang, D., Hall, M., Liu, L., Hurst, R., Su, Y., Encell, L., Kim, N., Casey, K., Kirkland, T., Lin, M. AMER CHEMICAL SOC. 2019
  • Total abdominal ultra-rapid flash irradiation decreases gastrointestinal toxicity compared to conventional radiation Levy, K., Rafat, M., Casey, K., Rankin, E. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2019: 75
  • Preclinical testing of ultra-rapid FLASH total abdominal irradiation demonstrates survival benefit and decreased gastrointestinal toxicity compared to conventional external beam radiation. Levy, K., Rafat, M., Schueler, E., Eggold, J., Wang, J., Casey, K., Koong, A., Maxim, P., Loo, B. W., Rankin, E. AMER SOC CLINICAL ONCOLOGY. 2019
  • Remodeling of epigenome and transcriptome landscapes with aging in mice reveals widespread induction of inflammatory responses GENOME RESEARCH Benayoun, B. A., Pollina, E. A., Singh, P., Mahmoudi, S., Harel, I., Casey, K. M., Dulken, B. W., Kundaje, A., Brunet, A. 2019; 29 (4): 697–709
  • Western diet regulates immune status and the response to LPS-driven sepsis independent of diet-associated microbiome PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Napier, B. A., Andres-Terre, M., Massis, L. M., Hryckowian, A. J., Higginbottom, S. K., Cumnock, K., Casey, K. M., Haileselassie, B., Lugo, K. A., Schneider, D. S., Sonnenburg, J. L., Monack, D. M. 2019; 116 (9): 3688–94
  • SETD3 is an actin histidine methyltransferase that prevents primary dystocia NATURE Wilkinson, A. W., Diep, J., Dai, S., Liu, S., Ooi, Y., Song, D., Li, T., Horton, J. R., Zhang, X., Liu, C., Trivedi, D. V., Ruppel, K. M., Vilches-Moure, J. G., Casey, K. M., Mak, J., Cowan, T., Elias, J. E., Nagamine, C. M., Spudich, J. A., Cheng, X., Carette, J. E., Gozani, O. 2019; 565 (7739): 372-+
  • Pravastatin improves fetal survival in mice with a partial deficiency of heme oxygenase-1. Placenta Tsur, A. n., Kalish, F. n., Burgess, J. n., Nayak, N. R., Zhao, H. n., Casey, K. M., Druzin, M. L., Wong, R. J., Stevenson, D. K. 2019; 75: 1–8

    Abstract

    Statins induce heme oxygenase-1 (HO-1) expression in vitro and in vivo. Low HO-1 expression is associated with pregnancy complications, e.g. preeclampsia and recurrent miscarriages. Here, we investigated the effects of pravastatin on HO-1 expression, placental development, and fetal survival in mice with a partial HO-1 deficiency.At E14.5, untreated pregnant wild-type (WT, n=13-18), untreated HO-1+/- (Het, n=6-9), and Het mice treated with pravastatin (Het+Pravastatin, n=12-14) were sacrificed. Numbers of viable fetuses/resorbed concepti were recorded. Maternal livers and placentas were harvested for HO activity. Hematoxylin and eosin (H&E) and CD31 immunohistochemical staining were performed on whole placentas.Compared with WT, HO activity in Het livers (65±18%, P<0.001) and placentas (74±7%, P<0.001) were significantly decreased. Number of viable fetuses per dam was significantly lower in Untreated Het dams (6.0±2.2) compared with WT (9.1±1.4, P<0.01), accompanied by a higher relative risk (RR) for concepti resorption (17.1, 95% CI 4.0-73.2). In Hets treated with pravastatin, maternal liver and placental HO activity increased, approaching levels of WT controls (to 83±7% and 87±14%, respectively). The number of viable fetuses per dam increased to 7.7±2.5 with a decreased RR for concepti resorption (2.7, 95% CI 1.2-5.9). In some surviving Untreated Het placentas, there were focal losses of cellular architecture and changes suggestive of reduced blood flow in the labyrinth. These findings were absent in Het+Pravastatin placentas.Pravastatin induces maternal liver and placental HO activity, may affect placental function and improve fetal survival in the context of a partial deficiency of HO-1.

    View details for PubMedID 30712660

  • Pravastatin improves fetal survival in mice with a partial deficiency of heme oxygenase-1 PLACENTA Tsur, A., Kalish, F., Burgess, J., Nayak, N. R., Zhao, H., Casey, K. M., Druzin, M. L., Wong, R. J., Stevenson, D. K. 2019; 75: 1–8
  • Validation of a geropathology grading system for aging mouse studies. GeroScience Snyder, J. M., Snider, T. A., Ciol, M. A., Wilkinson, J. E., Imai, D. M., Casey, K. M., Vilches-Moure, J. G., Pettan-Brewer, C. n., Pillai, S. P., Carrasco, S. E., Salimi, S. n., Ladiges, W. n. 2019

    Abstract

    An understanding of early-onset mechanisms underlying age-related changes can be obtained by evaluating changes that precede frailty and end of life using histological characterization of age-related lesions. Histopathology-based information as a component of aging studies in mice can complement and add context to molecular, cellular, and physiologic data, but there is a lack of information regarding scoring criteria and lesion grading guidelines. This report describes the validation of a grading system, designated as the geropathology grading platform (GGP), which generated a composite lesion score (CLS) for comparison of histological lesion scores in tissues from aging mice. To assess reproducibility of the scoring system, multiple veterinary pathologists independently scored the same slides from the heart, lung, liver, and kidney from two different strains (C57BL/6 and CB6F1) of male mice at 8, 16, 24, and 32 months of age. There was moderate to high agreement between pathologists, particularly when agreement within a 1-point range was considered. CLS for all organs was significantly higher in older versus younger mice, suggesting that the GGP was reliable for detecting age-related pathology in mice. The overall results suggest that the GGP guidelines reliably distinguish between younger and older mice and may therefore be accurate in distinguishing between experimental groups of mice with more, or less, age-related pathology.

    View details for DOI 10.1007/s11357-019-00088-w

    View details for PubMedID 31468322

  • Proliferative Typhlocolitis With Multinucleated Giant Cells: A Nonspecific Enteropathy in Immunodeficient Sentinel Mice VETERINARY PATHOLOGY Casey, K. M., Johnson, A. L., Hunrath, M. N., Fraser, J. K., McCowan, N. C., Wasson, K., Doty, R. A., Griffey, S. M., Imai, D. M. 2019; 56 (1): 157–68
  • Evaluation of 3 Alcohol-based Agents for Presurgical Skin Preparation in Mice. Journal of the American Association for Laboratory Animal Science : JAALAS Huss, M. K., Casey, K. M., Hu, J. n., Moorhead, R. C., Chum, H. H. 2019

    Abstract

    Appropriate aseptic technique is a crucial component of rodent survival surgery. Ease of technique, surgical space constraint,batch surgery, and cost are factors that may affect researcher compliance with appropriate aseptic technique. The first part of this study compared 3 antiseptic preparation agents with the standard triplicate application of povidone-iodine and alcohol. Euthanized mice (n = 40) were shaved on the dorsum, and culture swabs were taken for RODAC plating and bacterial identification. Shaved sites were prepared by using one of the 4 antiseptic preparation agents. Culture samples were obtained immediately and at 20 min after antiseptic preparation. In the 2nd part of the study, 8 mice (n = 2 per group)were prepared for a survival surgical procedure by using one of the 4 antiseptic preparation agents to evaluate whether the antiseptic preparation agents caused skin irritation or impaired healing. Results from this study indicated that all 3 of the antiseptic agents evaluated were equally effective at reducing bacterial populations immediately and at 20 min after preparation. Histopathologic examination of the incision sites revealed signs of normal healing without lesions adjacent to the incision site. We conclude that all 3 of the products evaluated are comparable to traditional povidone-iodine and alcohol as agents for aseptic preparation of surgical sites.

    View details for DOI 10.30802/AALAS-JAALAS-19-000053

    View details for PubMedID 31753064

  • What is your diagnosis? Conjunctival smear in a dog VETERINARY CLINICAL PATHOLOGY Gonzales-Viera, O., Casey, K., Keel, M. 2018; 47 (3): 509-510

    View details for DOI 10.1111/vcp.12620

    View details for Web of Science ID 000444081200026

  • What is your diagnosis? Conjunctival smear in a dog. Veterinary clinical pathology Gonzales-Viera, O., Casey, K., Keel, M. K. 2018

    View details for PubMedID 29989194

  • Pravastatin Induces Heme Oxygenase Activity and Enhances Placental Development in a Murine Model. Tsur, A., Kalish, F., Burgess, J., Zhao, H., Casey, K. M., Druzin, M. L., Wong, R. J., Stevenson, D. K. SAGE PUBLICATIONS INC. 2018: 155A–156A
  • Pravastatin improves pregnancy outcome and placental development in heme oxygenase-1 deficient mice Tsur, A., Kalish, F., Burgess, J., Zhao, H., Casey, K., Druzin, M. L., Wong, R. J., Stevenson, D. K. MOSBY-ELSEVIER. 2018: S202
  • TREATMENT WITH PRAVASTATIN IMPROVES PREGNANCY OUTCOME AND PLACENTAL DEVELOPMENT IN HEME OXYGENASE-1-DEFICIENT MICE Tsur, A., Kalish, F., Burgess, J., Zhao, H., Casey, K. M., Druzin, M. L., Wong, R. J., Stevenson, D. K. BMJ PUBLISHING GROUP. 2018: 241–42
  • SETD3 is an actin histidine methyltransferase that prevents primary dystocia. Nature Wilkinson, A. W., Diep, J. n., Dai, S. n., Liu, S. n., Ooi, Y. S., Song, D. n., Li, T. M., Horton, J. R., Zhang, X. n., Liu, C. n., Trivedi, D. V., Ruppel, K. M., Vilches-Moure, J. G., Casey, K. M., Mak, J. n., Cowan, T. n., Elias, J. E., Nagamine, C. M., Spudich, J. A., Cheng, X. n., Carette, J. E., Gozani, O. n. 2018

    Abstract

    For more than 50 years, the methylation of mammalian actin at histidine 73 has been known to occur1. Despite the pervasiveness of His73 methylation, which we find is conserved in several model animals and plants, its function remains unclear and the enzyme that generates this modification is unknown. Here we identify SET domain protein 3 (SETD3) as the physiological actin His73 methyltransferase. Structural studies reveal that an extensive network of interactions clamps the actin peptide onto the surface of SETD3 to orient His73 correctly within the catalytic pocket and to facilitate methyl transfer. His73 methylation reduces the nucleotide-exchange rate on actin monomers and modestly accelerates the assembly of actin filaments. Mice that lack SETD3 show complete loss of actin His73 methylation in several tissues, and quantitative proteomics analysis shows that actin His73 methylation is the only detectable physiological substrate of SETD3. SETD3-deficient female mice have severely decreased litter sizes owing to primary maternal dystocia that is refractory to ecbolic induction agents. Furthermore, depletion of SETD3 impairs signal-induced contraction in primary human uterine smooth muscle cells. Together, our results identify a mammalian histidine methyltransferase and uncover a pivotal role for SETD3 and actin His73 methylation in the regulation of smooth muscle contractility. Our data also support the broader hypothesis that protein histidine methylation acts as a common regulatory mechanism.

    View details for PubMedID 30626964

  • Identification of occult micrometastases and isolated tumour cells within regional lymph nodes of previously diagnosed non-metastatic (stage 0) canine carcinomas VETERINARY AND COMPARATIVE ONCOLOGY Casey, K. M., Steffey, M. A., Affolter, V. K. 2017; 15 (3): 785–92

    Abstract

    Metastatic dissemination of carcinomas to lymph nodes impacts prognosis and treatment recommendations in human and veterinary medicine. Routine histopathologic evaluation of regional lymph nodes involves haematoxylin and eosin (H&E) staining to identify intra-nodal neoplastic cells; however, identification of small volume metastases (micrometastases and individual tumour cells) may be missed without the aid of immunohistochemistry or additional step-sections. The aim of this study was to identify occult carcinoma metastases in previously diagnosed non-metastatic lymph nodes using step-sections and pancytokeratin (panCK) immunohistochemistry. Samples from 20 regional lymph nodes diagnosed as non-metastatic were serially sectioned and evaluated with panCK. Of these, 25% (n = 5) contained micrometastases (n = 1) or isolated tumour cells (n = 4). This study demonstrates the increased efficacy of serial step-sections combined with panCK immunohistochemistry to identify small volume metastases in regional lymph nodes. The prognostic significance of micrometastases and isolated tumour cells in regional lymph nodes warrants further investigation in veterinary medicine.

    View details for DOI 10.1111/vco.12219

    View details for Web of Science ID 000408772500013

    View details for PubMedID 27135991

  • Partial gastrectomy for resection of a gastric leiomyoma in a guinea pig (Cavia porcellus) JAVMA-JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION Gardhouse, S. M., Guzman, D., Sadar, M. J., DeRouen, A. J., Bucy, D. S., Adedeji, A. O., Vernau, W., Casey, K. M., Mohr, F., Steffey, M. A. 2016; 249 (12): 1415–20

    Abstract

    CASE DESCRIPTION A 4-year-old sexually intact male pet guinea pig (Cavia porcellus) was evaluated for a routine wellness examination. CLINICAL FINDINGS During physical examination, a small mass was palpated in the cranial aspect of the abdomen. Abdominal radiographic and ultrasonographic findings were suggestive of a gastric mass. Cytologic evaluation of a fine-needle aspirate of the mass was indicative of spindle cell proliferation most consistent with a sarcoma. TREATMENT AND OUTCOME The patient was anesthetized, and an exploratory laparotomy and partial gastrectomy were performed to resect the gastric mass. Histologic and immunohistochemical examinations of the mass revealed that it was a gastric leiomyoma. The patient recovered from surgery without complications. No evidence of mass recurrence was observed during an abdominal ultrasonographic examination performed approximately 19 months after surgery. CLINICAL RELEVANCE To our knowledge, this was the first report of the clinical diagnosis and successful surgical treatment of a gastric neoplasm in a guinea pig. Gastric leiomyomas are not uncommon in guinea pigs, and although benign, they can cause clinical signs if they become large enough to impair gastric function. Gastrointestinal surgery should be considered as a treatment option for guinea pigs with similar gastric neoplasms.

    View details for DOI 10.2460/javma.249.12.1415

    View details for Web of Science ID 000388906500016

    View details for PubMedID 27901456

  • Bilateral Aural Adenocarcinoma in a Congo African Grey Parrot (Psittacus erithacus erithacus) JOURNAL OF AVIAN MEDICINE AND SURGERY Houck, E. L., Keller, K. A., Hawkins, M. G., Burton, A. G., Casey, K. M., Keel, K., Tong, N., Guzman, D. 2016; 30 (3): 257–62

    Abstract

    A 28-year-old female Congo African grey parrot ( Psittacus erithacus erithacus) was evaluated because of a mass in the left external auditory meatus. Results of a computed tomography scan revealed an osteolytic left hemimandibular mass with irregular bone production and a soft tissue mass in the left external auditory meatus. Results of cytologic examination of fine needle aspirates of the hemimandible were interpreted as adenocarcinoma with reactive osteoblasts. The owner chose palliative treatment, and a debulking procedure was performed on the left external auditory meatus mass 52 days after initial presentation to control self-trauma. Euthanasia was elected 67 days after initial presentation because of poor prognosis associated with the development of bilateral masses of the external auditory meatus and lateral deviation of the mandible, findings that were confirmed by postmortem examination. Histopathologic results confirmed the diagnosis of bilateral aural adenocarcinoma with invasion of both temporal bones and hemimandibles.

    View details for Web of Science ID 000385596600006

    View details for PubMedID 27736232

  • Bilaterally Symmetric Focal Cortical Dysplasia in a Golden Retriever Dog JOURNAL OF COMPARATIVE PATHOLOGY Casey, K. M., Bollen, A. W., Winger, K. M., Vernau, K. M., Dickinson, P. J., Higgins, R. J., Siso, S. 2014; 151 (4): 375–79

    Abstract

    A 10-year-old golden retriever dog was referred with a 24-h history of generalized seizures. Magnetic resonance imaging of the brain found no abnormalities on 3 mm transverse sections and the dog was subsequently humanely destroyed. Microscopically there was bilaterally symmetrical focal disorganization of cortical grey matter within the tips of the right and left suprasylvian gyri of the temporal cortex. The focal abnormal cortical lamination was characterized by loss of pyramidal neurons with abnormal, irregular, angular, remaining neurons occasionally forming clusters, surrounded by fibrillary astrogliosis and microgliosis and vascular proliferation. These histological findings are consistent with focal cortical dysplasia, a cerebral cortical malformation that causes seizures in people, but not reported previously in the dog.

    View details for DOI 10.1016/j.jcpa.2014.08.002

    View details for Web of Science ID 000347662200011

    View details for PubMedID 25246180

  • Reproductive Experience Alters Neural and Behavioural Responses to Acute Oestrogen Receptor alpha Activation JOURNAL OF NEUROENDOCRINOLOGY Byrnes, E. M., Casey, K., Carini, L. M., Bridges, R. S. 2013; 25 (12): 1280–89

    Abstract

    Reproductive experience (i.e. parturition and lactation) leads to persistent alterations in anxiety-like behaviour that are influenced by the oestrous cycle. We recently found that repeated administration of the selective oestrogen receptors (ER)α agonist propyl-pyrazole triol (PPT) results in anxiolytic-like behaviours on the elevated plus maze (EPM) in primiparous (but not nulliparous) female rats. The present study examined the effects of the acute administration of PPT on EPM behaviour in primiparous and aged-matched, nulliparous female rats. In addition, corticosterone secretion, corticotrophin-releasing hormone (CRH) gene expression and expression of the immediate early gene product Fos in the paraventricular nucleus (PVN) and amygdala were measured either after EPM testing or in home cage controls. Acute PPT administration significantly modified EPM behaviour as a function of reproductive experience, with nulliparous females tending toward increased anxiety-like behaviours and primiparous females tending toward decreased anxiety-like behaviours. In home cage controls, PPT increased corticosterone secretion in all females; however, both vehicle- and PPT-treated, primiparous females had reduced corticosterone levels compared to their nulliparous counterparts. Significant effects of PPT on CRH mRNA within the PVN were observed after the administration of PPT but only in primiparous females tested on the EPM. PPT also increased Fos expression within the PVN of EPM-exposed females; however, both vehicle- and PPT-treated primiparous females had reduced Fos expression compared to nulliparous females. In the amygdala, PPT increased Fos immunoreactivity in the central but not the medial or basolateral amygdala, although these effects were only observed in home cage females. Additionally, both vehicle- and PPT-treated home cage, primiparous females had increased Fos in the central nucleus of the amygdala compared to nulliparous controls. Overall, these data demonstrate that reproductive experience alters the behavioural response to acute ERα activation. Moreover, the findings suggest that central regulation of the hypothalamic-adrenal-pituitary axis is modified as a consequence of reproductive experience.

    View details for DOI 10.1111/jne.12113

    View details for Web of Science ID 000327295200006

    View details for PubMedID 24118285

    View details for PubMedCentralID PMC4269101

  • Reproductive experience modifies the effects of estrogen receptor alpha activity on anxiety-like behavior and corticotropin releasing hormone mRNA expression HORMONES AND BEHAVIOR Byrnes, E. M., Casey, K., Bridges, R. S. 2012; 61 (1): 44–49

    Abstract

    Previous studies have demonstrated that prior reproductive experience can influence anxiety-like behaviors, although neural mechanisms underlying this shift remain unknown. Studies in virgin females suggest that activation of the two estrogen receptor subtypes, ERα and ERβ, have differing effects on anxiety. Specifically, ERβ activation has been shown to reduce anxiety-like behaviors, while ERα activation has no significant effect. The purpose of the present study was to examine the possible roles of ERα and ERβ subtypes in parity-induced alterations in anxiety-like behavior, as tested on the elevated plus maze (EPM). Groups of ovariectomized, age-matched, nulliparous and primiparous females were tested on the EPM following administration of the ERα agonist 4,4',4''-(4-Propyl-{1H}-pyrazole-1,3,5-tryl)trisphenol (PPT; 1 mg/kg), the ERβ agonist Diarylpropionitrile (DPN; 1 mg/kg) or vehicle (DMSO). All drugs were administered once daily for 4 days prior to testing as this dosing paradigm has previously been used to demonstrate anxiolytic effects of DPN in virgin rats. In addition, as exposure to the EPM is a psychological stressor, physiological markers of the stress response were measured in both plasma (corticosterone) and brain (corticotropin releasing hormone; CRH) post-EPM testing. Unexpectedly, the ERα agonist PPT selectively increased the time spent exploring the open arms of the EPM in non-lactating, primiparous females, with no significant effects of DPN observed in either nulliparous or primiparous subjects. All females administered PPT and tested on the EPM demonstrated significantly reduced corticosterone secretion when compared to vehicle-treated controls. In addition, significant effects of both reproductive experience and PPT administration on CRH mRNA expression were observed in both the paraventricular nucleus and amygdala using qPCR. These findings indicate that reproductive experience modulates the effects of ERα activation on both EPM behavior related to anxiety and CRH gene expression.

    View details for DOI 10.1016/j.yhbeh.2011.10.001

    View details for Web of Science ID 000300120000008

    View details for PubMedID 22033279

    View details for PubMedCentralID PMC3264805