Plasma concentrations of inflammatory markers in previously laminitic ponies.

The research work studied systemic inflammation markers in ponies with previous incidence of laminitis, a painful condition affecting the horse’s feet. The study discovered that recurrent laminitis may be linked with reduced anti-inflammatory capacity, with the marker adiponectin being significantly lower in previously laminitic ponies.

Introduction and Methodology

• The researchers sought to understand the reasons for certain ponies’ predisposition to pasture-associated laminitis — a condition which remains largely unclear and suspected to involve chronic inflammation.
• In particular, they aimed to identify differences in the inflammatory profile among ponies with previous episodes of laminitis, in comparison to healthy ones.
• The observation was made during the late spring and winter seasons in a group of previously laminitic (PL) and nonlaminitic (NL) ponies.
• Body condition score, height, weight, and crest height and thickness were measured, and plasma concentrations of various inflammatory markers, cytokines (tumour necrosis factor-α, interleukin-17, interleukin-4, interferon-γ), and other regimen (serum amyloid A, haptoglobin, insulin, adiponectin, triglyceride, fibrinogen) were assayed.
• The factors independently associated with each cytokine were also determined using multivariate analysis.

Results

• The most compelling finding was that plasma adiponectin concentration was significantly affected by the laminitis status — lower in PL ponies compared to NL ones.
• No other cytokines or inflammatory markers were associated with laminitis status.
• Plasma fibrinogen and serum amyloid A concentrations differed significantly based on the sex of the pony (higher in geldings than in mares) and the season (higher in winter than in late spring).
• Serum haptoglobin concentration also followed a similar pattern, with a notable inverse association with the weight of the ponies.
• A significant seasonal difference was observed for serum interleukin-4 concentration (higher in winter than in late spring).
• Serum insulin and plasma triglyceride concentrations had significant variations, influenced by the season and the laminitis status of the ponies, respectively.

Conclusions

• The study found significant influences of season, gender, and body weight on several proinflammatory mediators or markers of inflammation.
• Plasma adiponectin concentration, an anti-inflammatory marker, was the only marker affected by laminitis status, and was found to be lower in ponies with a history of laminitis.
• Significance of these results point out that instead of a pro-inflammatory state, recurrent laminitis might be associated with a diminished anti-inflammatory capacity.