BACKGROUND/ OBJECTIVE: Apoptosis, or programmed cell death, is an evolutionary conserved mechanism essential for morphogenesis and tissue homeostasis, but it plays an important role also in pathologic conditions, including neurologic disorders. Its execution pathway is critically regulated at the mitochondrial level. Evidence of apoptosis in muscle specimens was investigated in patients with genetically defined mitochondrial encephalomyopathies. METHODS: Thirty-three muscle biopsies from patients with genotypically different mitochondrial diseases (single and multiple deletions, A3243G/A8344G point mutations of the mitochondrial DNA) were studied. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) reaction was used as a marker of nuclear DNA fragmentation, as well as antibodies against pro- (Fas) or anti- (Bcl-2) apoptotic factors. Also, because one hallmark of apoptosis is morphologic, ultrastructural studies were performed on skeletal muscle from 18 of 33 patients, examining both phenotypically normal and ragged red fibers. RESULTS: In all muscle biopsies, no significant expression of either pro (Fas) and inhibiting (Bcl-2) apoptosis-related proteins was found, nor TUNEL positivity. This latter finding is confirmed by lack of morphologic evidence of apoptosis in all the fibers examined at the ultrastructural level. CONCLUSION: The authors' findings suggest that genetically determined defects of oxidative phosphorylation do not induce the apoptotic process and that apoptosis is not involved in the pathogenesis of mitochondrial disorders.
BACKGROUND/ OBJECTIVE: Apoptosis, or programmed cell death, is an evolutionary conserved mechanism essential for morphogenesis and tissue homeostasis, but it plays an important role also in pathologic conditions, including neurologic disorders. Its execution pathway is critically regulated at the mitochondrial level. Evidence of apoptosis in muscle specimens was investigated in patients with genetically defined mitochondrial encephalomyopathies. METHODS: Thirty-three muscle biopsies from patients with genotypically different mitochondrial diseases (single and multiple deletions, A3243G/A8344G point mutations of the mitochondrial DNA) were studied. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) reaction was used as a marker of nuclear DNA fragmentation, as well as antibodies against pro- (Fas) or anti- (Bcl-2) apoptotic factors. Also, because one hallmark of apoptosis is morphologic, ultrastructural studies were performed on skeletal muscle from 18 of 33 patients, examining both phenotypically normal and ragged red fibers. RESULTS: In all muscle biopsies, no significant expression of either pro (Fas) and inhibiting (Bcl-2) apoptosis-related proteins was found, nor TUNEL positivity. This latter finding is confirmed by lack of morphologic evidence of apoptosis in all the fibers examined at the ultrastructural level. CONCLUSION: The authors' findings suggest that genetically determined defects of oxidative phosphorylation do not induce the apoptotic process and that apoptosis is not involved in the pathogenesis of mitochondrial disorders.
Authors: Benjamin J Grady; David C Samuels; Gregory K Robbins; Doug Selph; Jeffrey A Canter; Richard B Pollard; David W Haas; Robert Shafer; Spyros A Kalams; Deborah G Murdock; Marylyn D Ritchie; Todd Hulgan Journal: J Acquir Immune Defic Syndr Date: 2011-12-01 Impact factor: 3.731
Authors: Andrea Cortese; Arianna Tucci; Giovanni Piccolo; Carlo A Galimberti; Pietro Fratta; Enrico Marchioni; Gianpiero Grampa; Cristina Cereda; Gaetano Grieco; Ivana Ricca; Alan Pittman; Patrizia Ciscato; Laura Napoli; Valeria Lucchini; Michela Ripolone; Raffaella Violano; Gigliola Fagiolari; Sara E Mole; John Hardy; Arrigo Moglia; Maurizio Moggio Journal: Neurology Date: 2014-05-14 Impact factor: 9.910