GI07 - Spatial Transcriptomic Profiling of Stunted Villi in Yorkshire Terriers with Protein Losing Enteropathy

Abstract: Background Yorkshire terriers (YT) commonly develop a severe form of protein-losing enteropathy (PLE) associated with ectatic small intestinal crypts and stunted villi. Distended crypts and blunted, stunted villi have been associated with hypoalbuminemia, but the factors leading to these morphological lesions are unknown. Hypothesis/objectives Differences in gene expression in stunted versus healthy villi will provide novel insights into the pathogenesis of PLE in YT. Animals Archived formalin-fixed paraffin-embedded (FFPE) duodenal endoscopic biopsies from 8 YT with PLE. Methods FFPE slides were examined using H&E histology to select regions of interest (ROIs) comparing abnormal (stunted) and normal appearing villi, as well as epithelial (PanCK positive) and non-epithelial cells within the same section. Differential gene expression between ROIs was evaluated with Nanostring’s GeoMx Digital Spatial profiler. Quality control and pre-processing were performed with the GeoMxTools R package. Normalization, batch-correction, differential expression, and cellular deconvolution were performed using the StandR package. Results Differences in gene expression (P < .05) between stunted and normal villi were characterized by increased expression of genes related to epithelial stress responses (e.g., GLUD1, ADH4) and myofibroblast activation (e.g., ACTA2, TMP1). Genes with reduced relative expression in stunted villi included those involved in intestinal lipid transport (e.g., APOA1, APOC3) and epithelial renewal (e.g., PRC1, PLK1, TOP2A). Conclusions and clinical importance Spatial transcriptomic profiling of stunted villi in the duodenal mucosa of YT with PLE identified disruption of pathways involving cellular stress, lipid transport, and epithelial renewal that may be involved in disease pathogenesis.