Larsen 2012 Acta Physiol (Oxf): Difference between revisions
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|instruments=Oxygraph-2k | |instruments=Oxygraph-2k | ||
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Revision as of 15:31, 15 June 2015
Larsen S, Hey-Mogensen M, Rabol R, Stride N, Helge JW, Dela F (2012) The influence of age and aerobic fitness: Effects on mitochondrial respiration in skeletal muscle. Acta Physiol (Oxf) 205:423-32. |
Larsen S, Hey-Mogensen M, Rabol R, Stride N, Helge JW, Dela F (2012) Acta Physiol (Oxf)
Abstract: AIM: Mitochondrial function has previously been studied in ageing, but never in humans matched for maximal oxygen uptake (VยทO2max). Furthermore, the influence of ageing on mitochondrial substrate sensitivity is not known.
METHODS: Skeletal muscle mitochondrial respiratory capacity and mitochondrial substrate sensitivity was measured by respirometry in young (23ยฑ3 years) and middle-aged (53ยฑ3 years) male subjects with similar VยทO2max. Protocols for respirometry included titration of substrates for complexI (glutamate), complexII (succinate) and both (octanoyl-carnitine) for calculation of substrate sensitivity (C(50) ). Myosin Heavy Chain (MHC) isoforms, citrate synthase (CS) and ฮฒ-hydroxy-acyl-CoA-dehydrogenase (HAD) activity, mitochondrial DNA (mtDNA) content, protein levels of complexes I-V and antioxidant defense system (manganese superoxide dismutase (MnSOD)) was measured.
RESULTS: No differences were found in maximal mitochondrial respiration or C(50) with glutamate (2.0ยฑ0.3 and 1.8ยฑ0.3 mmol/l), succinate (3.7ยฑ0.2 and 3.8ยฑ0.4 mmol/l) or octanoyl-carnitine (47ยฑ8 and 56ยฑ7 ฮผmol/l) in young and middle-aged subjects, respectively. Normalising mitochondrial respiration to mtDNA young subjects had a higher (P<0.05) respiratory capacity per mitochondrion compared to middle-aged subjects. HAD activity and mtDNA per mg tissue were higher in middle-aged compared to young subjects. Middle-aged had a higher MHC I isoform and a lower MHC IIX isoform content compared to young subjects.
CONCLUSION: Mitochondrial substrate sensitivity is not affected by ageing. When young and middle-aged men are carefully matched for VยทO2max, mitochondrial respiratory capacity is also similar. However, per mitochondrion respiratory capacity was lower in middle-aged compared to young subjects. Thus, when matched for VยทO2max middle-aged seems to require a higher mitochondrial content than young subjects.
โข O2k-Network Lab: DK Copenhagen Dela F
Labels:
Pathology: Aging;senescence
Organism: Human Tissue;cell: Skeletal muscle
Enzyme: Complex I, Complex II;succinate dehydrogenase Regulation: Substrate
HRR: Oxygraph-2k