Effects of acute hyperinsulinemia on inflammatory proteins in horses.

This research examines the effects of acute hyperinsulinemia on inflammatory proteins in horses, seeking to investigate a potential relationship between increased plasma insulin concentrations and laminitis, an inflammatory hoof disease.

Objective of the Study

The primary aim of this study was to investigate whether increased plasma insulin concentrations would produce a rise in plasma concentrations of inflammatory cytokines, and cytokine mRNA abundance in subcutaneous adipose tissue, skeletal muscle, and white blood cells in horses. This may indicate a role for insulin in the production of inflammatory cytokines, and potentially help to explain the increased risk of laminitis associated with high plasma insulin levels.

Methodology

• For this study, ten mature Thoroughbred mares were chosen. The researchers used an insulin infusion to artificially elevate plasma insulin concentrations for six hours.
• The study was conducted using a switchback design, with each horse receiving the insulin infusion and an equivalent amount of isotonic saline — presumably serving as the control condition.

Findings

• The results showed that the insulin infusion led to changes in plasma concentrations of two inflammatory cytokines, TNF and IL-6, confirming the hypothesis.
• However, the insulin infusion did not lead to consistent changes in cytokine mRNA in either skeletal muscle or adipose tissue. This implies that the elevated insulin concentration drives an inflammatory response, but it may not impact the genetic expression of these cytokines in the tissues studied.

Conclusion and Implications

The findings provide evidence that insulin may play a role in the production of inflammatory cytokines, potentially explaining how elevated insulin levels contribute to the development of laminitis in horses. However, further research is needed to fully understand the precise molecular mechanisms linking insulin and inflammation. This could eventually open new therapeutic avenues for preventing or treating laminitis.