Fatty acid composition of serum lipid fractions in type 2 diabetic patients with microalbuminuria

Abstract

OBJECTIVE - To determine the fatty acid composition of serum phospholipid, triglyceride, and cholesterol ester fractions and to analyze the lipid profile of microalbuminuric type 2 diabetic patients. RESEARCH DESIGN AND METHODS - A case-control study was conducted with 72 patients: 37 were normoalbuminuric (urinary albumin excretion rate [UAER] <20 μg/min), and 35 were microalbuminuric (UAER 20-200 μg/min). After 4 weeks of a standardized diet, the fatty acid composition of phospholipid, triglyceride, and cholesterol ester fractions was determined by gas chromatography. Total cholesterol and triglycerides were measured by enzymatic-colorimetric methods; cholesterol HDL by double precipitation with heparin, MnCl2, and dextran sulfate; and apolipoprotein B by immunoturbidimetry. RESULTS - Microalbuminuric patients showed a lower proportion of polyunsaturated fatty acids (24.8 ± 11.0%), especially of the n-6 family (21.7 ± 10.5%), in triglyceride fraction than normoalbuminuric patients (34.1 ± 11.3%, P = 0.001 and 31.4 ± 11.5%, P < 0.001, respectively). Patients with microalbuminuria also presented higher levels of saturated fatty acids in triglyceride fraction (43.4 ± 18.0% vs. 34.7 ± 13.1%, P = 0.022). In the logistic regression analysis, only the proportion of polyunsaturated fatty acids in triglyceride fraction remained significantly associated with microalbuminuria (odds ratio [OR] 0.92, 95% CI 0.85-0.98, P = 0.019). Total cholesterol, HDL cholesterol, triglyceride, and apolipoprotein B levels were similar in normo- and microalbuminuric patients. CONCLUSION - Microalbuminuria in type 2 diabetic patients is associated with low polyunsaturated fatty acid contents in serum triglyceride fraction. This association may represent a risk factor for cardiovascular disease and may contribute to the progression of renal disease.