Objective: To determine if blood and peritoneal fluid levels of syndecan-1, heparan sulfate, and hyaluronan are elevated in horses with small intestinal disease compared to healthy counterparts.
Methods: 61 horses were categorized into control (n = 20), inflammatory (11), and strangulating (30) groups. Paired peritoneal fluid and blood samples were obtained from each group from December 2016 through December 2024 and analyzed via equine-validated ELISAs for syndecan-1, heparan sulfate, and hyaluronan concentrations. Patient survival to discharge was recorded for all groups. Immunofluorescence staining was performed on sections of healthy and diseased jejunum.
Results: Syndecan-1 concentrations were higher in horses with disease (inflammatory and strangulating lesions) compared to controls, in inflammatory peritoneal fluid relative to controls, and in horses that did not survive to discharge. Heparan sulfate concentrations were higher in diseased horses versus controls, in strangulating lesions compared to controls, and in horses that did not survive to discharge. Hyaluronan concentrations were higher in disease compared to control, lower in the peritoneal fluid of strangulating lesions, elevated in plasma from strangulating lesions, and higher in horses that did not survive to discharge. Immunofluorescence revealed a greater number of heparan sulfate-positive cells in diseased intestinal tissue.
Conclusions: These findings suggest that endothelial glycocalyx degradation is associated with small intestinal disease and nonsurvival to discharge in equine small intestinal colic.
Clinical relevance: Further investigation is needed to determine if measurement of endothelial glycocalyx biomarkers may offer a novel approach for assessing intestinal injury and guiding clinical decision-making in horses with gastrointestinal disease.
Keywords: colic; endothelial; glycocalyx; small intestine; strangulating.