Identification of methylenecyclopropyl acetic acid in serum of European horses with atypical myopathy.

The research suggests that atypical myopathy (AM) in European horses, a muscle disease, is likely caused by the ingestion of the toxic metabolite of hypoglycin A, methylenecyclopropyl acetic acid (MCPA). This finding mirrors what happens with seasonal pasture myopathy in North American horses and is linked to the ingestion of seeds from the tree Acer pseudoplatanus.

Research Objective

• The two main objectives of this research were to determine if MCPA-carnitine was present in the serum of European horses diagnosed with AM, and to confirm if the tree Acer negundo or related species was present on the affected pastures in Europe.

Methodology

• The researchers used retrospective study approach on previously collected samples.
• They analyzed the concentrations of MCPA-carnitine in stored serum samples of 17 AM-affected horses from Europe and 3 diseased control samples (cases of tetanus, neoplasia and exertional rhabdomyolysis) using a specialized scientific technique known as tandem mass spectrometry.
• AM was diagnosed through characteristic serum acylcarnitine profiles, a distinctive biochemical signature of the disease.
• The pastures of 12 farms with AM affected horses were visited by experienced botanists to document the plant species present.

Results

• High concentrations of MCPA-carnitine were observed in the AM horses but not in the disease control samples.
• The tree Acer pseudoplatanus was found to be present on all AM farms, whereas Acer negundo was not found.

Conclusion

• AM in Europe, like seasonal pasture myopathy in North America, is highly linked to the toxic metabolite of hypoglycin A, MCPA-carnitine.
• The presence of Acer pseudoplatanus trees, whose seeds are known to contain hypoglycin A, on all AM farms suggests that ingestion of this tree’s seeds is the probable cause of AM in Europe.
• This finding has significant implications for prevention as avoiding or limiting exposure to the seeds of Acer pseudoplatanus could prevent the disease.