The dynamic equilibrium between ATP synthesis and ATP consumption is lower in isolated mitochondria from myotubes established from type 2 diabetic subjects compared to lean control

• Published in: Biochemical and biophysical research communications Vol. 409; no. 4; pp. 591 - 595
• Main Authors: Minet, Ariane D., Gaster, Michael
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 17.06.2011
• Subjects: adenosine triphosphate; Adenosine Triphosphate - biosynthesis; Adenosine Triphosphate - metabolism; antibodies; ATP; centrifugation; Diabetes Mellitus, Type 2 - metabolism; Equilibrium; Female; females; gender differences; genes; hexokinase; Hexokinase - metabolism; Human skeletal muscle; Humans; insulin resistance; Male; males; Middle Aged; Mitochondria; Mitochondria, Muscle - metabolism; mitochondrial membrane; Muscle Fibers, Skeletal - metabolism; Myotubes; noninsulin-dependent diabetes mellitus; Obesity - metabolism; oxidative phosphorylation; skeletal muscle; Thinness - metabolism; RCR; HK; Myotubes; TCA cycle; mt; mom; wc; Equilibrium; Human skeletal muscle; MRS; Mitochondria; VDAC; ATP
• ISSN: 0006-291X; 1090-2104; 1090-2104
• DOI: 10.1016/j.bbrc.2011.04.028

► Mitochondrial ATP levels were evaluated at equilibrium between ATP synthesis and ATP utilization. ► Lower ATP levels at equilibrium in diabetic versus lean mitochondria isolated from myotubes. ► Mitochondrial dysfunction in type 2 diabetes in vivo is partly based on a primarily impaired ATP synthesis. Although, most studies of human skeletal muscle in vivo have reported the co-existence of impaired insulin sensitivity and reduced expression of oxidative phosphorylation genes, there is so far no clear evidence for whether the intrinsic ATP synthesis is primarily decreased or not in the mitochondria of diabetic skeletal muscle from subjects with type 2 diabetes. ATP synthesis was measured on mitochondria isolated from cultured myotubes established from lean (11/9), obese (9/11) and subjects with type 2 diabetes (9/11) (female/male, n=20 in each group), precultured under normophysiological conditions in order to verify intrinsic impairments. To resemble dynamic equilibrium present in whole cells between ATP synthesis and utilization, ATP was measured in the presence of an ATP consuming enzyme, hexokinase, under steady state. Mitochondria were isolated using an affinity based method which selects the mitochondria based on an antibody recognizing the mitochondrial outer membrane and not by size through gradient centrifugation. The dynamic equilibrium between ATP synthesis and ATP consumption is 35% lower in isolated mitochondria from myotubes established from type 2 diabetic subjects compared to lean control. The ATP synthesis rate without ATP consumption was not different between groups and there were no significant gender differences. The mitochondrial dysfunction in type 2 diabetes in vivo is partly based on a primarily impaired ATP synthesis.