Seasonal changes in plasma concentrations of cecum-derived amines in clinically normal ponies and ponies predisposed to laminitis.

The research article focuses on studying the variation in plasma concentrations of amines, formed in the cecum of ponies, during different seasons and comparing these concentrations in healthy ponies and ponies prone to laminitis. The study finds that amine concentrations increase significantly in spring, which could potentially contribute to blood flow disruptions in ponies with acute laminitis.

Methodology

• The researchers collected cecal contents from 10 ponies who were euthanized at an abattoir, and blood samples from 42 adult ponies for the experiment.
• Out of these 42 ponies, 20 were predisposed to acute laminitis, and 22 were clinically normal ones.
• The cecal contents were assayed for amines using high-performance liquid chromatography (HPLC).
• Blood samples were collected at different times in the year and analyzed. Plasma serotonin concentration was measured using HPLC, and the concentrations of tryptamine (TRP), tyramine (TYR), phenylethylamine (PEA), and isoamylamine (IAA) were measured using liquid chromatography-mass spectrometry.

Results

• A total of 15 amines were identified in the cecal contents of the ponies.
• The concentrations of TRP, TYR, PEA, and IAA in the plasma ranged between 10pM to 100nM in both groups of ponies.
• No significant difference was found in the concentration of serotonin or other amines between the healthy ponies and ponies predisposed to laminitis.
• However, the study found significantly higher concentrations of TRP, PEA, and IAA in blood samples collected during the spring as compared to the winter samples.

Conclusion

• The study confirmed that various amines are found in the cecum of ponies, several of which can be detected in the plasma.
• These concentrations significantly increase in the spring, and this upsurge may reach levels that could potentially cause vasoconstriction or narrowing of the blood vessels.
• The study concluded that the release of these amines from the cecum into the systemic circulation might contribute to hemodynamic disturbances in horses and ponies suffering from acute laminitis.