Plasma ubiquinol/cholesterol ratios in patients with hyperlipidaemia, those with diabetes mellitus and in patients requiring dialysis.

Plasma ubiquinol was measured in diabetics, patients on haemodialysis (HD) therapy, patients maintained by continuous ambulatory peritoneal dialysis (CAPD), hyperlipidaemic patients and control subjects. Ubiquinol values were standardized using total cholesterol (mumol/mmol). Diabetics, HD and CAPD patients were found to have plasma ubiquinol levels which were lower than the control subjects. There was no difference in values between the control subjects and hyperlipidaemic patients. Values for diabetics with poor metabolic control were similar to those with good control, and patients with diabetic complications had values which were not significantly different from those for patients with no complications. IDDM patients were found to have values which were lower than the control group, whereas values for the NIDDM patients were not significantly different. These results suggest that increased oxidative stress in certain patient groups may be the result of, and/or the cause of, decreased plasma ubiquinol. This could be due to increased demand or to decreased ability to regenerate the effective form of antioxidant.