Polymorphisms of endothelial nitric oxide synthase gene in systolic heart failure: an haplotype analysis.

BACKGROUND: Endothelial nitric oxide synthase (eNOS) gene polymorphisms have been associated with the pathogenesis of cardiovascular diseases, but few studies have evaluated the role of eNOS haplotypes on the risk and prognosis of heart failure (HF). This prospective study was designed to analyze the impact of three eNOS polymorphisms (T-786C, VNTR4a/b and Glu298Asp) and their haplotypes on the susceptibility and clinical outcomes in HF outpatients with systolic dysfunction. METHODS AND RESULTS: We conducted a case-control and a cohort study in which 316 HF patients and 360 healthy controls were recruited from a tertiary care university hospital. DNA was extracted from peripheral blood and eNOS polymorphisms were detected by PCR or PCR-RFLP. Patients were predominantly men, had a mean left ventricular ejection fraction of 31% and were followed-up for a median of 41months; there were 96 deaths, including 58 HF-related deaths. Genotype distribution of the eNOS T-786C, VNTR 4a/b and Glu298Asp was similar between HF patients and controls. Haplotype frequencies differed between HF patients and controls only in African-Brazilians (p=0.043). African-Brazilian patients that carried the haplotype -786C/4b/Asp298 had a better prognosis than patients that carried other haplotypes (log rank p value=0.016 for all-cause mortality). In a Cox proportional hazard model adjusted for clinical variables of risk, the -786C/4b/Asp298 haplotype remained as an independent genetic predictor of survival (adjusted HR=0.11; 95% CI=0.01-0.83; p=0.03). CONCLUSIONS: The -786C/4b/Asp298 eNOS haplotype had a significant impact on HF susceptibility and prognosis, particularly in African-Brazilian patients.

Matrix Metalloproteinase-2 Polymorphisms in Chronic Heart Failure: Relationship with Susceptibility and Long-Term Survival.

Circulating levels of matrix metalloproteinase-2 (MMP-2) predict mortality and hospital admission in heart failure (HF) patients. However, the role of MMP-2 gene polymorphisms in the susceptibility and prognosis of HF remains elusive. In this study, 308 HF outpatients (216 Caucasian- and 92 African-Brazilians) and 333 healthy subjects (256 Caucasian- and 77 African-Brazilians) were genotyped for the -1575G>A (rs243866), -1059G>A (rs17859821), and -790G>T (rs243864) polymorphisms in the MMP-2 gene. Polymorphisms were analyzed individually and in combination (haplotype), and positive associations were adjusted for clinical covariates. Although allele frequencies were similar in HF patients and controls in both ethnic groups, homozygotes for the minor alleles were not found among African-Brazilian patients. After a median follow-up of 5.3 years, 124 patients (40.3%) died (54.8% of them for HF). In Caucasian-Brazilians, the TT genotype of the -790G>T polymorphism was associated with a decreased risk of HF-related death as compared with GT genotype (hazard ratio [HR] = 0.512, 95% confidence interval [CI] 0.285-0.920). However, this association was lost after adjusting for clinical covariates (HR = 0.703, 95% CI 0.365-1.353). Haplotype analysis revealed similar findings, as patients homozygous for the -1575G/-1059G/-790T haplotype had a lower rate of HF-related death than those with any other haplotype combination (12.9% versus 28.5%, respectively; P = 0.010). Again, this association did not remain after adjusting for clinical covariates (HR = 0.521, 95% CI 0.248-1.093). Our study does not exclude the possibility that polymorphisms in MMP-2 gene, particularly the -790G>T polymorphism, might be related to HF prognosis. However, due to the limitations of the study, our findings need to be confirmed in further larger studies.