Fig. 5
Markers of mitochondrial biogenesis and oxidative metabolism in vastus lateralis muscle homogenates of COPD patients relative to controls. a Higher levels of mitochondrial biogenesis and oxidative metabolism markers in COPD (two-way ANOVA revealed the significant main effect of disease status, P < 0.01; TFAM and PGC-1α; COPD n = 17, controls n = 11, NRF1, PGC1β, PPAR δ, and PPAR γ; COPD n = 9 controls n = 9). b Significant correlation between upregulated mitochondrial biogenesis signals PGC-1α and TFAM in COPD patients (r 2 = 0.99, n = 10; P < 0.001). c Levels of TFAM protein in COPD patients (0.76 ± 0.14, n = 20) and control subjects (1.0 ± 0.23, n = 10; P = 0.18) assessed by Western blot. d Lower ratio of TFAM protein relative to TFAM mRNA in COPD patients (0.25 ± 0.07) compared to controls (0.94 ± 0.2; *P < 0.5). e Lower levels of citric synthase activity in COPD patients (4.62 ± 0.33, n = 19) than controls (13.44 ± 1.14, n = 14; ***P < 0.001). f Positive relationship between TFAM and CS exists in controls (r 2 = 0.67, P < 0.1) but not in COPD patients (r 2 < 0.1). Measured levels of CS activity in COPD are 51 % lower than predicted for the measured TFAM protein. Graphs show mean ± SEM