Gam 2011 Clin Physiol Funct Imaging
| Gam CM, Nielsen HB, Secher NH, Larsen FS, Ott P, Quistorff B (2011) In cirrhotic patients reduced muscle strength is unrelated to muscle capacity for ATP turnover suggesting a central limitation. Clin Physiol Funct Imaging 31: 169-174. |
Gam CM, Nielsen HB, Secher NH, Larsen FS, Ott P, Quistorff B (2011) Clin Physiol Funct Imaging
Abstract: BACKGROUND AND AIMS:We investigated whether in patients with liver cirrhosis reduced muscle strength is related to dysfunction of muscle mitochondria.
METHODS: The mitochondrial respiratory capacity of the tibial anterior muscle was evaluated in seven patients and eight healthy control subjects by 31P nuclear magnetic resonance spectroscopy (31PMRS) to express ATP turnover in vivo and by respirometry of permeabilized fibres from the same muscle to express the in vitro capacity for oxygen consumption.
RESULTS: Maximal voluntary contraction force for plantar extension was low in the patients (46% of the control value; P < 0.05), but neither the capacity for mitochondrial ATP synthesis, V(max-ATP) (0.38 ± 0.26 vs. 0.50 ± 0.07 mM s(-1) ; P = 0.13) nor the in vitro VO(2max) (0.52 ± 0.21 vs. 0.48 ± 0.21 μmol O2 (min g wet wt.)(-1) P = 0.25) were lowered correspondingly. Also, the activity of citrate synthesis and the respiratory chain complexes II and IV were similar in patients and controls. However during the contractions, the contribution to initial anaerobic ATP production from glycolysis relative to that from PCr was reduced in the patients (0.73 ± 0.22 vs. 0.99 ± 0.09; P < 0.01).
CONCLUSIONS: The results demonstrate that the markedly lower capacity for force generation in patients with liver cirrhosis is unrelated to their capacity for muscle ATP turnover, but the attenuated initial acceleration of anaerobic glycolysis suggests that these patients could be affected by a central limitation to force generation. • Keywords: ATP turnover, human skeletal muscle, liver cirrhosis, nuclear magnetic resonance spectroscopy, respirometry
• O2k-Network Lab: DK Copenhagen Quistorff B
Labels:
Organism: Human
Tissue;cell: Skeletal muscle
Preparation: Permeabilized tissue
HRR: Oxygraph-2k
