Polymorphisms of angiotensin converting enzyme and plasminogen activator inhibitor-1 genes in diabetes and macroangiopathy

Background. An insertion or deletion (I/D) polymorphism in the angiotensin converting enzyme (ACE) gene and a 4/5-guanine tract polymorphism (4G/5G) in the promoter region of the plasminogen activator inhibitor-1 (PAI-1) gene are associated with the plasma activities of these substances and with coronary heart disease. In smooth muscle cells and mesangial cells, the angiotensin II synthesized by ACE increases mRNA expression and the activity of PAI-1, which promotes antifibrinolysis and the accumulation of extracellular matrix. Therefore, ACE and PAI-1 polymorphisms may have a synergistic effect on diabetic nephropathy and macroangiopathy. Methods. Using multivariate logistic regression analyses, we investigated the independent or synergistic effects of the ACE IID and PAI-1 4G/5G polymorphisms on the development of diabetic nephropathy and macroangiopathy in 208 patients with noninsulin dependent diabetes mellitus (NIDDM) over a 15 year period. Results. Advanced diabetic nephropathy, defined as impaired renal function and diabetic retinopathy, was present in 98 patients. Manifest macrovascular diseases, confirmed by both clinical signs and physical and laboratory examinations, were present in 56 patients. There was no significant difference in the genotype distribution of ACE or PAI-1 polymorphisms between subjects with advanced nephropathy and those with normal renal function. There was no significant difference in the renal survival rate between patients with differing ACE or PAI-1 genotypes. Subjects with macroangiopathy had a higher frequency of the DD genotype than those without macroangiopathy. Subjects with both DD and 4G4G genotypes had a higher incidence of macroangiopathy than those with any other pair of genotypes. Multivariate logistic regression analysis showed that there was no association between ACE or PAI-1 polymorphisms and diabetic nephropathy. The ACE DD genotype and its interaction with the PAI-1 4G4G genotype and the presence of advanced diabetic nephropathy were positively associated with macrovascular disease. Conclusion. These results indicate that the ACE DD genotype and its interaction with the PAI-1 4G4G genotype are independent risk factors for macroangiopathy, but not for the progression of diabetic nephropathy in NIDDM patients, and that the genotyping of PAI-1 and ACE polymorphisms, especially in patients with advanced diabetic nephropathy, may be useful for predicting and preventing macroangiopathy-related events.