Impaired mitochondrial substrate oxidation in muscle of insulin-resistant offspring of type 2 diabetic patients.
Level 4 - case-series / case-control
Cross-sectional case-control physiological comparison study.
PubMed 17287462 · doi:10.2337/db06-0783
What was done
Investigators evaluated muscle mitochondrial substrate oxidation rates in young, lean, insulin-resistant offspring of type 2 diabetic patients compared with insulin-sensitive control subjects. In vivo substrate oxidation rates were measured noninvasively using 13C magnetic resonance spectroscopy (MRS) by tracking the incorporation of 13C label into C(4) glutamate during a [2-13C]acetate infusion.
What was found
Muscle mitochondrial substrate oxidation rates were 30% lower in lean, insulin-resistant offspring (59.8 ± 5.1 nmol × g⁻¹ × min⁻¹) compared with insulin-sensitive controls (96.1 ± 16.3 nmol × g⁻¹ × min⁻¹, P = 0.02).
Why it matters
The findings indicate that mitochondrial metabolic impairment in skeletal muscle is present in young, lean individuals at high risk for diabetes before the onset of overt disease.
Limits
The abstract does not state the sample size (n) or exact demographic breakdown. The observational case-control design demonstrates an association but cannot prove whether reduced mitochondrial oxidation causes insulin resistance or results from it.
Cited by
- contradicts Mitochondria in type 2 diabetics function at half the rate of mitochondria in people without type 2 diabetes.