[en] Introduction: Exertional rhabdomyolyses are a common cause of exercise intolerance in the equine athlete, and Polysaccharide Storage Myopathy (PSSM) is a widely described muscular pathology. It is characterized by an accumulation of abnormal glycogen in myofibers due to a genetic defect in the skeletal muscle glycogen synthase (GYS1) enzyme. We hypothesized that the energetic production through the oxidative phosphorylation (OXPHOS) in muscular mitochondria might be impaired in type-1 PSSM-affected horses.
Material and Methods: Eight horses with a history of exertional rhabdomyolysis were tested for the GYS1 mutation. Muscle biopsies were collected and used for histological analysis and high resolution respirometry (HRR). HRR values from 3 groups of horses (PSSM-positive horses, horses with a history of myopathy but negative to PSSM and healthy controls) were compared using a linear mixed model to take into account repeated (2-3 times) measurements made for each horse.
Results: In four horses histology revealed an accumulation of abnormal glycogen in myofibers. A severe depression of the maximal OXPHOS capacity was observed by HRR in all horses with exertional rhabodmyolysis, with lower values in PSSM-positive cases.
Conclusions: Our study shows a severe decreased OXPHOS capacity in PSSM-affected horses. PSSM is considered primarily a defect in glycogen synthesis but altered OXPHOS might play a central role in its pathogenesis.
Disciplines :
Veterinary medicine & animal health
Author, co-author :
Tosi, Irène ; Université de Liège - ULiège > Département de sciences fonctionnelles > Phys. neuro-muscul., de l'effort - Méd. sport. des animaux
Art, Tatiana ; Université de Liège - ULiège > Département de sciences fonctionnelles > Phys. neuro-muscul., de l'effort - Méd. sport. des animaux
Cassart, Dominique ; Université de Liège - ULiège > Département de morphologie et pathologie > Département de morphologie et pathologie
Serteyn, Didier ; Université de Liège - ULiège > Département clinique des animaux de compagnie et des équidés > Anesthésiologie gén. et pathologie chirurg. des grds animaux
Votion, Dominique ; Université de Liège - ULiège > Scientifiques attachés au Doyen (F MV)
Language :
English
Title :
Altered mitochondrial oxidative phosphorylation capacity in horses suffering from polysaccharide storage myopathy