Preliminary investigation into a potential role for myostatin and its receptor (ActRIIB) in lean and obese horses and ponies.
Authors: Morrison Philippa K, Bing Chen, Harris Patricia A, Maltin Charlotte A, Grove-White Dai, Argo Caroline McG
Journal: PloS one
Summary
Obesity in leisure horses and ponies represents a significant metabolic challenge, yet the underlying physiological mechanisms remain incompletely understood; myostatin, a muscle-derived hormone that negatively regulates skeletal muscle mass and communicates systemically via myokine secretion, emerged as a candidate factor in this investigation. Morrison and colleagues compared gene and protein expression profiles of myostatin and its receptor (ActRIIB) in skeletal muscle and adipose tissue samples from six lean and six obese equines, whilst also measuring circulating myostatin concentrations. Obese animals demonstrated markedly elevated serum myostatin levels (9.00 ng/ml versus 4.98 ng/ml in lean controls) alongside increased myostatin mRNA expression in skeletal muscle and crest fat, though interestingly these gene-level changes did not consistently translate to elevated protein expression at tissue level. The positive correlation between circulating myostatin and muscle gene expression (R² = 0.58) suggests myostatin may contribute to the metabolic dysregulation characteristic of equine obesity, potentially through impaired muscle mass maintenance and altered whole-body energy expenditure. For practitioners, these findings indicate that targeting myostatin signalling pathways could represent a novel therapeutic angle for managing obesity, though further investigation into whether elevated myostatin is a cause or consequence of obesity—and whether interventions to suppress it would prove beneficial—remains essential before clinical application.
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Practical Takeaways
- •Myostatin dysregulation may be involved in obesity development in horses and ponies, suggesting potential therapeutic targets for weight management strategies
- •Circulating myostatin levels could potentially serve as a biomarker for obesity status, though further validation studies are needed
- •Weight management programmes should consider the role of skeletal muscle metabolism and myokine signalling as part of whole-body energy regulation
Key Findings
- •Obese horses and ponies had significantly higher circulating myostatin concentrations (9.00 ng/ml) compared to lean animals (4.98 ng/ml)
- •Myostatin mRNA expression was increased in skeletal muscle of obese animals, with positive correlation to serum myostatin levels (R² = 0.58)
- •ActRIIB mRNA was decreased in skeletal muscle of obese animals, but no protein-level differences were detected
- •Myostatin mRNA was elevated in crest fat (a site of increased fat deposition in obese horses) of obese animals