Accumulation of CK-MM is impaired in innervated and contracting cultured muscle fibers of Duchenne muscular dystrophy patients.
No specific abnormalities have been reproducibly manifested in aneurally cultured muscle of Duchenne muscular dystrophy (DMD) patients. We now report that the accumulation of the muscle-"specific" isozyme of creatine kinase (CK-MM) was significantly and preferentially impaired in long-term innervated contracting muscle fibers cultured from 4 DMD patients (DMD-InnCMFs) compared to: i) their noninnervated sister-cultured muscle fibers, and ii) innervated contracting control cultured human muscle fibers (Control-InnCHMFs). Accumulation of other muscle-"specific" isozymes (MSIs), viz. glycogen phosphorylase, phosphoglycerate mutase, and lactic dehydrogenase, was not significantly impaired. We have not observed preferentially-impaired CK-MM accumulation in any Control-InnCHMFs from 22 patients (children and adults) with a variety of neuromuscular diseases. There was no apparent difference between DMD-InnCMFs and Control InnCHMFs regarding: acceptance of innervation; neuronally-driven, virtually continuous muscle-fiber contractions; characteristic myofiber organization by phase-contrast microscopy, and increased longevity of the innervated fibers.
D000818:Animals; D002648:Child; D003402:Creatine Kinase / Q000378:metabolism*; D046508:Culture Techniques / Q000379:methods; D005727:Ganglia, Spinal / Q000502:physiology*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000201:enzymology* / Q000294:innervation; D009136:Muscular Dystrophies / Q000201:enzymology* / Q000473:pathology; D009474:Neurons / Q000502:physiology; D051381:Rats
D007527:Isoenzymes; D003402:Creatine Kinase