In vitro and in vivo studies of homocysteine in equine tissues: implications for the pathophysiology of laminitis.

The research article explores the role of homocysteine (HCy) in equine vascular endothelial cell function and the implications for laminitis, a common hooved animal disease. Despite the initial hypothesis, the study did not find a direct correlation between high plasma HCy concentrations and an increased risk of laminitis in horses.

Research Objectives

• The research had two primary goals: firstly, to determine the concentration of HCy in vitro which inhibits the function of equine vascular endothelial cells; secondly, to identify any potential link between the risk of laminitis, a painful condition in hooved animals, and plasma HCy concentrations.

Methodology

• The research employed in vitro and in vivo studies. The function of endothelium was examined by evaluating endothelium-dependent vasodilatory responses of the equine isolated perfused digit, essentially an isolated section of horse hoof in a controlled environment, and basal nitric oxide (NO) production by cultured equine digital vein endothelial cells (EDVECs).
• Concentration measurements of total plasma homocysteine (tHCy) were carried out using samples collected during winter and spring seasons from both normal ponies and those predisposed to laminitis.

Results

• Findings from the study showed that HCy inhibited endothelial function, and above 100 micromol/l, it also inhibited the NO production by EDVECs.
• Measured plasma tHCy concentrations ranged from 13 to 14.7 micromol/l, and the results did not show any seasonal or disease status influence on this concentration.

Conclusions

• The study established that HCy interferes with the function of endothelial cells at physiological concentrations. However, contrary to the initial hypothesis, the research did not find a definitive link between higher levels of plasma HCy and an increased risk of laminitis.
• The researchers conclude that any practices that could potentially raise plasma HCy concentrations should still be avoided in ponies that are more susceptible to laminitis, given the established adverse impact of HCy on endothelial cell function.