Relationship between level of circulating modified LDL and the extent of coronary artery disease in type 2 diabetic patients.

The impact of diabetes on health is due almost entirely to a series of complications that characterise the disease. It is associated with an increased incidence of macrovascular complications including coronary artery disease (CAD). The aim of the present study is to evaluate the possible relationship between the circulating levels of the modified derivatives of low-density lipoprotein (LDL) and the development of angiopathy in type 2 diabetic patients with CAD. The status of the antioxidant defences and the role of supplementation with antioxidant combinations are also studied in these patients. The study was conducted on three groups: group I (controls); group II (type 2 diabetic patients without complications--CAD[-]); and group III (including type 2 diabetic patients with stable CAD - CAD[+]). Patients in group III received adjunct treatment of antioxidant tablets for three months. The results of the present study clearly indicated that there was excessive exposure to oxidative stress in diabetic patients. The increase in free radicals was coupled with disturbance in free radical scavengers, particularly the glutathione system. The disturbance was more prominent in CAD(+) patients. The study has shown alteration in the lipid profile in diabetic groups, where the oxidised LDL (ox-LDL) levels were significantly higher than in control subjects. Diabetics with CAD had higher levels of ox-LDL than did patients without CAD. The intima/media thickness (IMT) of the carotid artery was within clinically accepted normal values if the ox-LDL level was below 100-110 u/L. Once the ox-LDL exceeded this range, IMT increased sharply with the increase in plasma ox-LDL. It seems that the level of ox-LDL should be kept below an upper limit of the 100-110 u/L range in order to avoid the serious atherosclerotic effects of this factor. The results demonstrate that plasma levels of ox-LDL correlate with the extent of coronary artery disease in type 2 diabetic patients and suggest that elevated levels of ox-LDL, can serve as an independent and significant predictor for future cardiac events in type 2 diabetic patients with CAD.