A German case study involving a young mare has found further evidence that Equine Atypical Myopathy (EAM) is caused by ingestion of sycamore maple tree seeds.
The four researchers set out to evaluate the hypothesis that the ingestion of sycamore maple tree seeds containing hypoglycin A (HGA) – a toxic amino acid – caused acquired Multiple Acyl-CoA Dehydrogenase Deficiency (MADD) and might be associated with the clinical and pathological signs of EAM.
The disease leads to the destruction of muscle tissue, including the heart.
The mare in question had died following the development of clinical signs of progressive muscle stiffness and recumbency. Before death, she had ingested sycamore maple tree seeds (Acer pseudoplatanus).
Robert Klopfleisch and his colleagues performed a necropsy and microscopic tissue examination, and looked for metabolites – byproducts – of HGA in blood and urine samples from the mare.
Their compared their data with three geldings with no clinical history of myopathy.
They found fragments of maple tree seeds in the stomach of the mare and severe myopathy affecting several muscle groups.
Microscopic examination of the affected muscles showed severe, acute rhabdomyolysis with extensive accumulation of finely dispersed fat droplets in the cytoplasm of degenerated skeletal muscle cells that were not present in the geldings.
Urine and serum concentrations of several acyl carnitines and acyl glycines were increased and both contained metabolites of HGA.
The study supported the hypothesis that ingestion of HGA-containing maple tree seeds may cause EAM due to acquired MADD, they reported.
Their paper, entitled “Equine Atypical Myopathy caused by Hypoglycin A intoxication associated with ingestion of sycamore maple tree seeds”, has been accepted for publication in the Equine Veterinary Journal.
Equine Atypical Myopathy caused by Hypoglycin A intoxication associated with ingestion of sycamore maple tree seeds
A. Żuraw, K. Dietert, S. Kühnel, J. Sander and R. Klopfleisch.
The abstract can be read here.