Overexpression of semicarbazide-sensitive amine oxidase in human myopathies

• Published in: Muscle & nerve Vol. 29; no. 2; pp. 261 - 266
• Main Authors: Olivé, Montse, Unzeta, Mercè, Moreno, Dolores, Ferrer, Isidro
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.02.2004; Wiley
• Subjects: Aged; Amine Oxidase (Copper-Containing) - biosynthesis; Amine Oxidase (Copper-Containing) - genetics; Biological and medical sciences; desmin-related myopathies; Diseases of striated muscles. Neuromuscular diseases; Female; Gene Expression Regulation, Enzymologic - physiology; Humans; inclusion-body myositis; Male; Medical sciences; Middle Aged; Muscle Fibers, Skeletal - enzymology; Muscle Fibers, Skeletal - pathology; muscle necrosis; muscle regeneration; Muscular Diseases - enzymology; Muscular Diseases - genetics; Muscular Diseases - pathology; Myositis - enzymology; Myositis - genetics; Myositis - pathology; Neurology; oxidative-stress; Rhabdomyolysis - enzymology; Rhabdomyolysis - genetics; Rhabdomyolysis - pathology; SSAO; Human; Immunopathology; Connective tissue disease; Oxidative stress; Skin disease; Enzyme; Pathogenesis; Dermatomyositis; Gene overexpression; Autoimmune disease; Muscular fiber; Rhabdomyolysis; Gene expression; desmin-related myopathies; inclusion-body myositis; muscle necrosis; muscle régénération; Amine oxidase (copper-containing); Necrosis; Striated muscle disease; Systemic disease; oxidative-stress; SSAO; Myositis; Reinnervation; Oxidoreductases; Denervation; Myopathy
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.10550

Oxidative stress has been implicated in the pathogenesis of several muscle diseases. Semicarbazide‐sensitive amine oxidase (SSAO) metabolizes oxidative deamination of primary aromatic and aliphatic amines. In the oxidative reactions, amine substrates are converted into the aldehyde, followed by the production of ammonia and H2O2. Although normal levels in muscle are very low, SSAO is expressed in almost all mammalian tissues. In this study, we examined the possible implication of SSAO as an additional source of oxidative stress in the pathogenesis of muscle disorders. The expression of SSAO was examined immunohistochemically in muscle biopsy specimens from patients with inclusion‐body myositis (IBM; n = 5), desmin‐related myopathy (DRM; n = 3), dermatomyositis (n = 3), granulomatous (sarcoid) myopathy (n = 2), muscle denervation–reinnervation (n = 3), and rhabdomyolysis (n = 2), as well as from control subjects (n = 3). Strong SSAO immunoreactivity was present in vacuolated and nonvacuolated fibers in IBM, in abnormal fibers in DRM, and in degenerating and regenerating fibers in dermatomyositis and rhabdomyolysis. In addition, SSAO overexpression was observed in muscle fibers adjacent to granulomas in sarcoid myopathy. These results suggest that SSAO is a source of oxidative stress in diseased human skeletal muscle and that it contributes to oxidative stress‐induced damage in various inflammatory and other myopathies. Alternatively, the expression of SSAO in muscle fibers may be a consequence of muscle fiber injury. Muscle Nerve 29: 261–266, 2004