Coenzyme Q(10) improves endothelial dysfunction of the brachial artery in Type II diabetes mellitus.
OBJECTIVE
We assessed whether dietary supplementation with coenzyme Q(10) improves endothelial function of the brachial artery in patients with Type II (non-insulin-dependent) diabetes mellitus and dyslipidaemia.


METHODS
A total of 40 patients with Type II diabetes and dyslipidaemia were randomized to receive 200 mg of coenzyme Q(10) or placebo orally for 12 weeks. Endothelium-dependent and independent function of the brachial artery was measured as flow-mediated dilatation and glyceryl-trinitrate-mediated dilatation, respectively. A computerized system was used to quantitate vessel diameter changes before and after intervention. Arterial function was compared with 18 non-diabetic subjects. Oxidative stress was assessed by measuring plasma F(2)-isoprostane concentrations, and plasma antioxidant status by oxygen radical absorbance capacity.


RESULTS
The diabetic patients had impaired flow-mediated dilation [3.8 % (SEM 0.5) vs 6.4 % (SEM 1.0), p = 0.016], but preserved glyceryl-trinitrate-mediated dilation, of the brachial artery compared with non-diabetic subjects. Flow-mediated dilation of the brachial artery increased by 1.6 % (SEM 0.3) with coenzyme Q(10) and decreased by -0.4 % (SEM 0.5) with placebo (p = 0.005); there were no group differences in the changes in pre-stimulatory arterial diameter, post-ischaemic hyperaemia or glyceryl-trinitrate-mediated dilation response. Coenzyme Q(10) treatment resulted in a threefold increase in plasma coenzyme Q(10) (p < 0.001) but did not alter plasma F(2)-isoprostanes, oxygen radical absorbance capacity, lipid concentrations, glycaemic control or blood pressure.


CONCLUSIONS
Coenzyme Q(10) supplementation improves endothelial function of conduit arteries of the peripheral circulation in dyslipidaemic patients with Type II diabetes. The mechanism could involve increased endothelial release and/or activity of nitric oxide due to improvement in vascular oxidative stress, an effect that might not be reflected by changes in plasma F(2)-isoprostane concentrations.
Watts
G F
GF
Department of Medicine, University of Western Australia, Royal Perth Hospital, Perth, Australia. gfwatts@cyllene.uwa.edu.au
Playford
D A
DA
Croft
K D
KD
Ward
N C
NC
Mori
T A
TA
Burke
V
V
D000975:Antioxidants / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D001916:Brachial Artery / Q000187:drug effects / Q000503:physiopathology*; D002784:Cholesterol / Q000097:blood; D003067:Coenzymes; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000517:prevention & control*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000517:prevention & control; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008875:Middle Aged; D010919:Placebos; D012039:Regional Blood Flow / Q000187:drug effects; D014280:Triglycerides / Q000097:blood; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D014664:Vasodilation / Q000187:drug effects
D000975:Antioxidants; D003067:Coenzymes; D008074:Lipoproteins; D010919:Placebos; D014280:Triglycerides; D014451:Ubiquinone; D002784:Cholesterol; C024989:coenzyme Q10