Growth factor and receptor mRNA expression in the intestine of horses with large colon volvulus: a pilot study.
Authors: Southwood L L, Lindermann J, Zarucco L, Driessen B, Olander H, Habecker P, Birks E K, Frisbie D D
Journal: Equine veterinary journal
Summary
# Editorial Summary Large colon volvulus causes significant intestinal ischaemia and reperfusion injury in horses, but the molecular mechanisms underlying mucosal damage and recovery remain poorly understood. Southwood and colleagues investigated mRNA expression of three key growth factor families—epidermal growth factor (EGF), insulin-like growth factor-I (IGF) and vascular endothelial growth factor (VEGF)—and their receptors in experimentally induced and naturally occurring large colon volvulus, comparing ischaemic tissue (1 hour post-volvulus) and early reperfusion phase (1 hour post-correction) against normal baseline samples from small intestine, pelvic flexure and right dorsal colon using quantitative reverse-transcription PCR and histological assessment. The most striking finding was significantly elevated VEGF and VEGF receptor expression in volvulus cases, suggesting an active angiogenic response; notably, IGF receptor expression increased specifically in the small intestine during both ischaemic and reperfusion phases. These upregulations likely reflect the intestine's attempted repair mechanisms, though elevated VEGF may paradoxically contribute to increased vascular permeability and the systemic inflammatory sequelae clinicians observe clinically. For practitioners managing post-surgical colic cases, particularly those involving small intestinal lesions, these findings underscore the importance of careful post-operative monitoring and suggest that understanding individual variation in growth factor responses may eventually help predict which horses face higher risk of delayed complications such as ileus or adhesion formation.
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Practical Takeaways
- •VEGF upregulation in large colon volvulus may be a protective mechanism for early intestinal healing but also contributes to increased vascular permeability and tissue edema
- •IGF pathway activation in small intestine during ischemia-reperfusion suggests potential therapeutic targets to improve outcomes after small intestinal surgical correction
- •Monitoring mRNA expression patterns of growth factors could provide insight into prognosis and guide post-operative management strategies in horses recovering from large colon volvulus
Key Findings
- •VEGF and VEGF-R mRNA expression increased in horses with large colon volvulus compared to normal intestine
- •IGF-R mRNA expression increased in small intestine during ischemia and reperfusion phases
- •Increased VEGF expression may contribute to vascular permeability changes in large colon volvulus
- •Growth factor receptor expression patterns warrant further investigation for understanding post-operative complications