A morphological and quantitative immunohistochemical study of the interstitial cells of Cajal in the normal equine intestinal tracts.
Authors: Pavone S, Mandara M T
Journal: Equine veterinary journal
Summary
# Editorial Summary Interstitial cells of Cajal (ICC) orchestrate intestinal motility through electrical and mechanical signalling, and reduced ICC populations have been documented in equine grass sickness and other dysmotility conditions, yet baseline reference data for normal horses remained scarce. Pavone and Mandara immunostained jejunal to small colon tissue samples from five clinically normal horses using anti-c-Kit antibodies and quantified ICC density across anatomical regions via image analysis software. Three ICC populations were identified: myenteric ICC (IC-MY) predominated throughout the small intestine and showed peak density in the right ventral colon and small colon, whilst intramuscular ICC in the circular muscle layer (IC-CM) clustered notably at the ileocaecal junction—a region of high functional demand—and longitudinal layer ICC (IC-LM) appeared substantial in the ileum and ileocaecal junction. These numerical baseline data provide clinicians and researchers with quantitative reference standards against which pathological specimens can be compared, establishing a framework for detecting ICC depletion in cases of suspected grass sickness or other motility disorders. For practitioners managing horses with chronic colic or dysmotility, this work underscores the biological rationale for pursuing definitive diagnosis through biopsy sampling, as ICC density loss may explain clinical signs undetectable through conventional examination alone.
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Practical Takeaways
- •This study establishes baseline ICC density values for normal horses, providing a reference standard for diagnosing ICC deficiencies in cases of grass sickness or other dysmotility disorders
- •The regional variation in ICC distribution along the intestinal tract suggests different motility control mechanisms at different sites, which may inform targeted diagnostic or therapeutic approaches
- •Image analysis quantification of c-Kit expression offers a standardized, reproducible method for veterinarians to assess ICC involvement in equine intestinal disease cases
Key Findings
- •Two types of ICC were identified in equine intestine: intramuscular ICC (in circular and longitudinal muscle layers) and myenteric ICC
- •Myenteric ICC density was highest throughout the small intestine and greatest in right ventral colon and small colon
- •Intramuscular circular ICC density was highest at the ileocaecal junction; caecum and left ventral/dorsal colon showed lowest c-Kit immunoreactivity
- •Image analysis using anti-c-Kit antibody is a rapid and reproducible method for quantifying normal ICC density in equine intestinal tract