TY - JOUR
T1 - Mitochondrial biogenesis and angiogenesis in skeletal muscle of the elderly
AU - Iversen, Ninna
AU - Krustrup, Peter
AU - Rasmussen, Hans N
AU - Rasmussen, Ulla F
AU - Saltin, Bengt
AU - Pilegaard, Henriette
N1 - CURIS 2011 5200 052
PY - 2011/8
Y1 - 2011/8
N2 - The aim of this study was to test the hypotheses that 1) skeletal muscles of elderly subjects can adapt to a single endurance exercise bout and 2) endurance trained elderly subjects have higher expression/activity of oxidative and angiogenic proteins in skeletal muscle than untrained elderly people. To investigate this, lifelong endurance trained elderly (ET; n=8) aged 71.3±3.4years and untrained elderly subjects (UT; n=7) aged 71.3±4years, performed a cycling exercise bout at 75% VO2max with vastus lateralis muscle biopsies obtained before (Pre), immediately after exercise (0h) and at 2h of recovery. Capillarization was detected histochemically and oxidative enzyme activities were determined on isolated mitochondria. GLUT4, HKII, Cyt c and VEGF protein expression was measured on muscle lysates from Pre-biopsies, phosphorylation of AMPK and P38 on lysates from Pre and 0h biopsies, while PGC-1α, VEGF, HKII and TFAM mRNA content was determined at all time points. ET had ~40% higher PDH, CS, SDH, α-KG-DH and ATP synthase activities and 27% higher capillarization than UT, reflecting increased skeletal muscle oxidative capacity with lifelong endurance exercise training. In addition, acute exercise increased in UT PGC-1α mRNA 11-fold and VEGF mRNA 4-fold at 2h of recovery, and AMPK phosphorylation ~5-fold immediately after exercise, relative to Pre, indicating an ability to adapt metabolically and angiogenically to endurance exercise. However, in ET PGC-1α mRNA only increased 5 fold and AMPK phosphorylation ~2-fold, while VEGF mRNA remained unchanged after the acute exercise bout. P38 increased similarly in ET and UT after exercise. In conclusion, the present findings suggest that lifelong endurance exercise training ensures an improved oxidative capacity of skeletal muscle, and that skeletal muscle of elderly subjects maintains the ability to respond to acute endurance exercise.
AB - The aim of this study was to test the hypotheses that 1) skeletal muscles of elderly subjects can adapt to a single endurance exercise bout and 2) endurance trained elderly subjects have higher expression/activity of oxidative and angiogenic proteins in skeletal muscle than untrained elderly people. To investigate this, lifelong endurance trained elderly (ET; n=8) aged 71.3±3.4years and untrained elderly subjects (UT; n=7) aged 71.3±4years, performed a cycling exercise bout at 75% VO2max with vastus lateralis muscle biopsies obtained before (Pre), immediately after exercise (0h) and at 2h of recovery. Capillarization was detected histochemically and oxidative enzyme activities were determined on isolated mitochondria. GLUT4, HKII, Cyt c and VEGF protein expression was measured on muscle lysates from Pre-biopsies, phosphorylation of AMPK and P38 on lysates from Pre and 0h biopsies, while PGC-1α, VEGF, HKII and TFAM mRNA content was determined at all time points. ET had ~40% higher PDH, CS, SDH, α-KG-DH and ATP synthase activities and 27% higher capillarization than UT, reflecting increased skeletal muscle oxidative capacity with lifelong endurance exercise training. In addition, acute exercise increased in UT PGC-1α mRNA 11-fold and VEGF mRNA 4-fold at 2h of recovery, and AMPK phosphorylation ~5-fold immediately after exercise, relative to Pre, indicating an ability to adapt metabolically and angiogenically to endurance exercise. However, in ET PGC-1α mRNA only increased 5 fold and AMPK phosphorylation ~2-fold, while VEGF mRNA remained unchanged after the acute exercise bout. P38 increased similarly in ET and UT after exercise. In conclusion, the present findings suggest that lifelong endurance exercise training ensures an improved oxidative capacity of skeletal muscle, and that skeletal muscle of elderly subjects maintains the ability to respond to acute endurance exercise.
U2 - 10.1016/j.exger.2011.03.004
DO - 10.1016/j.exger.2011.03.004
M3 - Journal article
C2 - 21504786
SN - 0531-5565
VL - 46
SP - 670
EP - 678
JO - Experimental Gerontology
JF - Experimental Gerontology
IS - 8
ER -