Figure 1.

Mitochondrial respiratory capacity in PBMCs. (A) Scheme of the mitochondrial electron transfer system (ETS) with the SUIT (substrate–uncoupler–inhibitor–titration) protocol that we used for evaluation of the mitochondrial respiratory capacity in the present study. (B) Summarized data of the O₂ consumption rate during each respiratory state with different respiratory substrates in the permeabilized PBMCs of obese (n = 14) and healthy control subjects (n = 15). The box bounds the interquartile range (IQR) divided by the median, and Tukey-style whiskers extend to a maximum of 1.5 × IQR beyond the box. The LEAK respiration indicates non-ADP stimulated respiration (i.e., state 2 respiration) with CI-linked substrates. The oxidative phosphorylation (OXPHOS) capacity, an ADP-stimulated respiration (i.e., state 3 respiration), was measured in the presence of CI− or CI+II-linked substrates. The maximal ETS capacity was measured after addition of FCCP, an uncoupler, in the presence of CI+CII-linked substrates. The capacity of complex IV was measured after addition of TMPD, an electron donor to cytochrome c (cyt c), in the presence of ascorbate. CI complex I, CII complex II, CIII complex III, CIV complex IV, CV complex V, UCP uncoupling protein.