LIPID-PEROXIDATION IN TYPE-2 DIABETES - RELATIONSHIP WITH MACROVASCULAR DISEASE

Background: Macrovascular disease is the leading cause of death in dia betes. The increased risk of atherosclerosis in diabetes may be partly explained by increased lipid peroxidation. Methods: We assessed Lipid peroxidation in subjects with type 2 diabetes with (n = 23) and witho ut (n = 23) macrovascular complications versus healthy age-matched con trols (n = 13). The diabetic groups were matched for glycemic control (mean HbA(1c) = 9%), and for age and had similar known duration of dia betes.Results: Plasma TEARS were comparable between diabetic subjects with and without macrovascular complications (1.89 +/- 0.32 and 1.81 /- 0.28 mu mol/l) and elevated compared to healthy controls (1.64 +/- 0.26 mu mol/l, p = 0.025). Ratios of IgG and IgM antibodies to oxidize d vs. native LDL were comparable between diabetic subjects and control s, and also between diabetic subjects with or without macrovascular co mplications. The lag phase, an index of the resistance of LDL to oxida tion, was significantly longer in diabetic patients with macrovascular complications (66 +/- 8 min) vs. those without macrovascular complica tions and controls (resp. 59 +/- 7 and 56 +/- 7 min, p < 0.05). An exp lanation may be the frequent use of drugs with possible antioxidant po tential, e.g. beta-blocking agents, ACE-inhibitors and calcium entry b lockers by these patients. Surprisingly, plasma vitamin E levels were higher in diabetic subjects. Conclusions: We found no evidence of incr eased lipid peroxidation in diabetic subjects with macrovascular compl ications, but an increased resistance to oxidation in this group, prob ably due to an altered antioxidant status. The increased TEARS level i n diabetic subjects contrasts with the other indices of lipid peroxida tion and may be related to prevalent hyperglycemia and should therefor e be interpreted cautiously. (C) 1998 Elsevier Science B.V. All rights reserved.