title: Aging, sex differences, and oxidative stress in human respiratory and limb muscles.
abstract: Oxidative stress is involved in the sarcopenia of aging muscles. On the grounds that ventilatory muscles are permanently active, and their activity may even increase with aging, we hypothesized that the levels of oxidative stress would probably be increased in the external intercostals of elderly healthy individuals. We conducted a case-control study in which reactive carbonyl groups, malondialdehyde-protein adducts, 3-nitrotyrosine immunoreactivity, Mn-superoxide dismutase (Mn-SOD), and catalase were detected using immunoblotting in external intercostals and quadriceps (open muscle biopsies) obtained from 12 healthy elderly and 12 young individuals of both sexes. In elderly subjects, reactive carbonyls, malondialdehyde-protein adducts, 3-nitrotyrosine, Mn-SOD, and catalase were significantly greater in the external intercostals than in the young controls. A post hoc analysis, in which men and women from both groups were analyzed separately, revealed that the external intercostals of elderly women, but not those of elderly men, showed significantly increased levels of reactive carbonyls, malondialdehyde-protein adducts, 3-nitrotyrosine, and Mn-SOD compared to those of control females. This study suggests that differences in muscle activity might explain the differential pattern of oxidative stress observed in human respiratory and limb muscles with aging as well as the likely existence of a sex-related regulation of this phenomenon in these muscles.
authors.affiliation: Muscle and Respiratory System Research Unit and Respiratory Medicine Department, IMIM Hospital del Mar, Universitat Pompeu Fabra, C/Dr. Aiguader, 80, Barcelona E-08003, Spain. ebarreiro@imim.es <ebarreiro@imim.es>
authors.forename: Esther
authors.initials: E
authors.lastname: Barreiro
authors.forename: Carlos
authors.initials: C
authors.lastname: Coronell
authors.forename: Barbara
authors.initials: B
authors.lastname: Laviña
authors.forename: Alba
authors.initials: A
authors.lastname: Ramírez-Sarmiento
authors.forename: Mauricio
authors.initials: M
authors.lastname: Orozco-Levi
authors.forename: Joaquim
authors.initials: J
authors.lastname: Gea
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging; D000975:Antioxidants / Q000737:chemistry; D001706:Biopsy; D002374:Catalase / Q000378:metabolism; D005260:Female; D005609:Free Radicals; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D012132:Respiratory Muscles / Q000378:metabolism*; D012737:Sex Factors; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D002374:Catalase; D013482:Superoxide Dismutase; D010100:Oxygen