Published in:
01-10-2016 | Short Communication
Metabolic flexibility and oxidative capacity independently associate with insulin sensitivity in individuals with newly diagnosed type 2 diabetes
Published in: Diabetologia | Issue 10/2016
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Aims/hypothesis
Both inherited and acquired insulin resistance have been associated with abnormal muscle mitochondrial function. At whole-body level, maximal oxygen uptake (\( \overset{.}{V}{\mathrm{O}}_{2 \max } \)) and/or metabolic flexibility (as given by ΔRQ) reflect certain features of mitochondrial function. This study tests the hypotheses (1) that \( \overset{.}{V}{\mathrm{O}}_{2 \max } \) and ΔRQ correlate tightly with each other and with insulin sensitivity and (2) that glycaemia, lipidaemia or subclinical inflammation would explain such relationships.
Methods
Near-normoglycaemic individuals with type 2 diabetes mellitus (n = 136) with a short known disease duration (<12 months) underwent cycling spiroergometry, indirect calorimetry and hyperinsulinaemic–euglycaemic clamp tests.
Results
Both \( \overset{.}{V}{\mathrm{O}}_{2 \max } \) (r = 0.39, p < 0.0001) and ΔRQ (r = 0.32, p < 0.0001) correlated positively with whole-body insulin sensitivity, even after adjusting for anthropometric variables, glycaemia and glucose-lowering medication, but not after adjusting for NEFA. \( \overset{.}{V}{\mathrm{O}}_{2 \max } \) further correlated negatively with circulating high-sensitivity C-reactive protein concentration. However, \( \overset{.}{V}{\mathrm{O}}_{2 \max } \) did not relate to ΔRQ, even after adjusting for whole-body insulin sensitivity.
Conclusions/interpretation
Oxidative capacity and metabolic flexibility are independent determinants of insulin sensitivity but are influenced by circulating NEFA in recent-onset type 2 diabetes.
ClinicalTrial.gov registration no: NCT01055093