Ageing is associated in females with a decline in the content and activity of the b-c1 complex in skeletal muscle mitochondria

Boffoli, Domenico; Scacco, Salvatore; Vergari, Rosaria; Persio, M. T.; Solarino, Giuseppe; Laforgia, R.; Papa, Sergio

doi:10.1016/0925-4439(95)00107-7

Cited by 47 publications

(27 citation statements)

References 19 publications

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“…27 Some sex-dependent differences in age-linked decline of mitochondrial respiration (eg specific activities of COX, NADH-cytochrome c reductase, UQH 2 -cytochrome c reductase) were also reported in humans. 28,29 There was reported lower COX activity in skeletal muscle in women than in men, but no differences in the CS activity were found. 30 In our study, no significant differences in the activities of COX and CS in lymphocytes were found between men and women, which is consistent with results of Pastoris et al, 31 who found no significant differences between males and females in the activities of various marker enzymes related to glycolysis, Krebs cycle and respiratory chain of human skeletal muscles.…”

Section: Effect Of Gendermentioning

confidence: 96%

Activities of cytochrome c oxidase and citrate synthase in lymphocytes of obese and normal-weight subjects

et al. 2002

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BACKGROUND: Obesity represents a heterogeneous group of disorders associated with broad spectrum of metabolic and endocrine abnormalities. The metabolic changes in obesity may also concern the efficacy of mitochondrial system of energy provision. The aim of our study was to analyse activities of mitochondrial enzymes cytochrome c oxidase (COX) and citrate synthase (CS) in isolated lymphocytes of obese and normal-weight subjects. RESULTS: In the group of 304 non-obese controls, differences between men and women were found neither in the COX and CS activities nor in the COX=CS ratio in isolated lymphocytes. The activity of COX did not change even with age, whereas the activity of CS decreased significantly resulting in age-dependent increase of the COX=CS ratio (P < 0.01). In the group of 60 obese patients aged 17 -75 y, the COX activity was 1.2-fold higher (P < 0.01) and the CS activity was 1.3-fold lower (P < 0.01) compared to 151 non-obese healthy age-matched controls. Consequently, the COX=CS ratio became 1.7-fold higher (P < 0.01) in the obese patients compared to the non-obese population, which indicates that both the absolute and relative oxidative capacity are increased. CONCLUSION: Isolated lymphocytes from peripheral blood contribute very little to the overall metabolic turnover, but they may serve as easily available marker cells for studying the changes of mitochondrial energy converting systems in obesity.

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Section: Effect Of Gendermentioning

confidence: 96%

Activities of cytochrome c oxidase and citrate synthase in lymphocytes of obese and normal-weight subjects

et al. 2002

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“…23 decreased activity of individual electron chain complexes, 24,25 mitochondria DNA 26 and mitochondrial transcription. 26 The decay in mitochondrial function is attributed to oxygen stress and free radical production 27 .…”

Section: Agingmentioning

confidence: 97%

Indirect measurement of mitochondrial proton leak and its application

et al. 1999

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In mitochondria, ATP synthesis is coupled to oxygen consumption by the proton electrochemical gradient established across the mitochondrial inner membrane in a process termed oxidative phosphorylation. It has long been known from stoichiometric studies that ATP synthesis is not perfectly coupled to oxygen consumption. The major inef®ciency in the system is leakage of protons across the mitochondrial inner membrane driven by the proton electrochemical gradient. The kinetics of the proton leak can be determined indirectly, by measuring the oxygen consumption of mitochondria under non-phosphorylating conditions (plus oligomycin) as a function of the proton electrochemical gradient. This experimental system provides a convenient means to investigate inner membrane permeability to protons and the effect of factors that may effect that permeability. In this paper we review some results from our laboratory of indirect measurement of mitochondrial proton leak and how it has been applied to investigate the effect of aging, obesity and thyroid status on proton leak. The results show that (i) proton leak in isolated liver mitochondria is not signi®cantly different in a comparison of young and old rats, in contrast (ii) there is an apparent increase in proton leak in in situ mitochondria in hepatocytes from old rats when compared to those from young rats, (iii) proton leak in neuronal mitochondria in situ in synaptosomes is not signi®cantly different in young and old rats, (iv) proton leak is greater in isolated liver mitochondria from obaob mice compared to lean controls, (v) acute leptin (OB protein) administration restores the increased leak rate in isolated liver mitochondria from obaob mice to that of lean controls, (vi) administration of thyroid hormone (T 3 ) increases proton leak in rat muscle mitochondria, and (vii) proton leak in muscle mitochondria is insensitive to the presence of GDP. It is proposed that the experimental system described here for measuring proton leak, is an ideal functional assay for determining whether the novel uncoupling proteins increase inner membrane permeability to protons.

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“…The decreased activity of citrate synthase in the mitochondria indicated that the age-related decline in skeletal muscle oxidative capacity is, most likely, the result of a decline in both mitochondrial content and function. Many other studies have shown an age-related decline in muscle mitochondrial content (8,30) and function (6,(31)(32)(33).…”

Section: Discussionmentioning

confidence: 99%

Effect of age onin vivorates of mitochondrial protein synthesis in human skeletal muscle

Rooyackers

Adey

Ades

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

519

393

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A progressive decline in muscle performance in the rapidly expanding aging population is causing a dramatic increase in disability and health care costs. A decrease in muscle endurance capacity due to mitochondrial decay likely contributes to this decline in muscle performance. We developed a novel stable isotope technique to measure in vivo rates of mitochondrial protein synthesis in human skeletal muscle using needle biopsy samples and applied this technique to elucidate a potential mechanism for the age-related decline in the mitochondrial content and function of skeletal muscle. The fractional rate of muscle mitochondrial protein synthesis in young humans (24 ؎ 1 year) was 0.081 ؎ 0.004%⅐h ؊1 , and this rate declined to 0.047 ؎ 0.005%⅐h ؊1 by middle age (54 ؎ 1 year; P < 0.01). No further decline in the rate of mitochondrial protein synthesis (0.051 ؎ 0.004%⅐h ؊1 ) occurred with advancing age (73 ؎ 2 years). The mitochondrial synthesis rate was about 95% higher than that of mixed protein in the young, whereas it was approximately 35% higher in the middle-aged and elderly subjects. In addition, decreasing activities of mitochondrial enzymes were observed in muscle homogenates (cytochrome c oxidase and citrate synthase) and in isolated mitochondria (citrate synthase) with increasing age, indicating declines in muscle oxidative capacity and mitochondrial function, respectively. The decrease in the rates of mitochondrial protein synthesis is likely to be responsible for this decline in muscle oxidative capacity and mitochondrial function. These changes in muscle mitochondrial protein metabolism may contribute to the age-related decline in aerobic capacity and muscle performance.

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Ageing is associated in females with a decline in the content and activity of the b-c1 complex in skeletal muscle mitochondria

Cited by 47 publications

References 19 publications

Activities of cytochrome c oxidase and citrate synthase in lymphocytes of obese and normal-weight subjects

Activities of cytochrome c oxidase and citrate synthase in lymphocytes of obese and normal-weight subjects

Indirect measurement of mitochondrial proton leak and its application

Effect of age onin vivorates of mitochondrial protein synthesis in human skeletal muscle

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