LIPIDS, LIPOPROTEINS, ANTIOXIDANTS AND GLOMERULAR AND TUBULAR DYSFUNCTION IN TYPE-1 DIABETES

We aimed to examine the relationship of serum lipids, lipoproteins, ap olipoproteins and antioxidants with renal dysfunction as measured by u rinary excretion of albumin and of retinol binding protein (REP) in in sulin-dependent diabetes mellitus (IDDM). We studied 121 patients with IDDM. Glomerular function was assessed as the urinary albumin/creatin ine ratio (U-A/U-C), and tubular function as the urinary retinol-bindi ng protein/creatinine ratio (U-R/U-C), both measured in three early mo rning spot urine samples. The mean (range) U-A/U-C was 1.95 mg/mmol (0 .3-476.5) and U-R/U-C was 17.5 mu g/mmol (1.0-1853.8). 17% of the pati ents had a U-A/U-C > 3 mg/mmol and 33% had a U-R/U-C > 20 mu g/mmol. S ignificant positive 'correlations were observed between both U-A/U-C a nd U-R/U-C and the following: serum total cholesterol (P < 0.005); tri glycerides(P < 0.001); apolipoproteins A-I (P < 0.05), A-II (P < 0.02) and B (P < 0.002); glycated haemoglobin (P < 0.002). No significant a ssociations were found with serum vitamin E, beta-carotene or total an tioxidant activity. In multiple regression, only U-A/U-C was independe ntly associated with serum apo B and cholesterol concentrations. In co nclusion, in IDDM glomerular dysfunction, as measured by U-A/U-C, is a ssociated with elevated serum cholesterol, triglycerides, apo B, apo A -I and apo A-II, but not with HDL cholesterol or antioxidant status. T ubular dysfunction tends to occur with increasing albuminuria, but it is not independently associated with serum lipid, lipoprotein, apolipo protein or antioxidant levels.