Skeletal Muscle Mitochondrial Respiration And Type 2 Diabetes Duration

초록

Type 2 diabetes (T2DM) resolution following Roux-en Y gastric bypass (RYGB) surgery is poorer in patients with longer duration T2DM and lower pre-RYGB insulin sensitivity. Skeletal muscle mitochondrial function is impaired in T2DM. PURPOSE : It was hypothesized that skeletal muscle mitochondrial respiration (JO2) would be lowest in T2DM patients with long-duration (LD; ≥ 8 y) compared to medium-duration (MD; 4-7) and short-duration (SD; ≤ 3 y). METHODS: Vastus lateralis biopsies were obtained from T2DM patients (N = 12). Muscle mitochondrial JO2 was measured using the permeabilized fiber technique under basal (State 2) and ADP stimulated (State 3) conditions with glutamate+malate (GM) or palmitoylcarnitine+malate (PM) as substrate. Respiratory control index (RCI), an index of mitochondrial coupling, was calculated as State 3/State 2 JO2. RESULTS : There was a non-significant (p = 0.10) trend of lower GM State 2 JO2 with longer T2DM duration (LD: 9.7 +/- 1.7; MD: 13.5 +/- 1.0; SD: 17.8 +/- 4.7 pmol/sec/mg dry wt.). GM RCI was greater in LD than MD or SD (LD: 21.3 +/- 1.8; MD: 12.6 +/- 2.4; SD: 13.8 +/- 1.3). There was a significant correlation between T2DM duration and GM RCI (r = 0.59; p ≤ 0.05). There was no difference in JO2 or RCI for PM conditions between groups. CONCLUSIONS : Skeletal muscle mitochondrial coupling is higher in longer compared to shorter duration T2DM patients. Also, there may be a trend toward lower basal skeletal muscle mitochondrial respiration in patients with longer compared to shorter duration T2DM.