Relationship among urinary albumin excretion rate, lipoprotein lipase PvuII polymorphism and plasma fibrinogen in type 2 diabetic patients

Plasma fibrinogen level represents a strong cardiovascular risk factor and is regulated by an interplay of genetic and environmental factors. Hyperfibrinogenemia frequently occurs in cluster with dyslipidemia within the frame of insulin resistance syndrome (IRS) and type 2 diabetes mellitus. Genetic variants with a pleiotropic effect have been proposed to cause IRS features including hyperfibrinogenemia. We studied the influence of polymorphisms in lipoprotein lipase (LPL) gene, beta-fibrinogen gene (FIBB) and environmental factors on plasma fibrinogen levels in type 2 diabetes patients. 131 type 2 diabetes patients (mean age 62+/-10 years, 33% male) were genotyped for polymorphisms in LPL gene (intron 6 PvuII, intron 8 HindIII) and FIBB gene (-148C/T, -455G/A) by PCR-RFLP method. Fibrinogen was measured by thrombin coagulation method, albuminuria by immunoturbidimetric assay. Polymorphism LPL PvuII showed a gene-dose effect on fibrinogen levels, with the highest fibrinogen in P-P- homozygotes (p = 0.05, analysis of variance). P-carriers (P-P- and P+P- combined) had significantly higher fibrinogen levels compared with P+P+ homozygotes (3.74+/-1.40 g/l vs 3.06+/-1.20 g/l, p=0.03). Other studied polymorphisms were not significantly related to fibrinogen levels. Age- and sex-adjusted fibrinogenemia correlated significantly with albuminuria (r = 0.48, p=0.001), serum uric acid (r = 0.42, p=0.006) and serum creatinine (r = 0.32, p=0.04). Multiple stepwise linear regression identified interaction term of LPL PvuII and albuminuria as an independent predictor of fibrinogen level, explaining 18% of fibrinogen variance. Albuminuria thus appears to be the best predictor of fibrinogen plasma levels in type 2 diabetic patients. Relationship between albuminuria and fibrinogenemia may be modified by the genotype LPL PvuII, which also shows a weak association with plasma fibrinogen level in type 2 diabetes patients.