Influence of VKORC1 gene polymorphisms on the effect of oral vitamin K supplementation in over-anticoagulated patients.

Significant inter-individual variability on the effect of vitamin K to reverse overanticoagulation has been identified. Genetic polymorphisms of the vitamin K epoxide reductase complex subunit 1 (VKORC1) gene might explain in part this variability. The objective of this study was to evaluate the influence of VKORC1 -1639G>A and 3730G>A polymorphisms on the effect of oral vitamin K supplementation in overanticoagulated patients. We performed an interventional trial of oral vitamin K supplementation in over-anticoagulated outpatients (international normalized ratio [INR] ≥ 4). Subjects received vitamin K (2.5-5.0 mg) according to baseline INR and were genotyped by real time polymerase chain reaction (PCR). INR values were determined at 3, 6, 24 and 72 h after supplementation. We evaluated 33 outpatients, 61 % were males, with a mean age of 62 ± 12 years old. There was a significant decrease in INR values over time for both polymorphisms after oral vitamin K. At 3 h after supplementation, patients carrying the G allele for the -1639G>A polymorphism had a greater decrease in INR values compared to AA patients (p < 0.05 for difference among groups; p < 0.001 for time variation; p = 0.001 for time × group interaction), with differences of -1.01 for GG versus AA (p = 0.003) and -0.84 for GA versus AA (p = 0.024). Mean INR value at 24 h was 1.9 ± 0.6 and at 72 h was 2.1 ± 0.7, with no differences among genotypes. No significant interaction was identified between the 3730G>A polymorphism and vitamin K supplementation. Our study indicated that the VKORC1 -1639G>A polymorphism plays a role in the response to acute vitamin K supplementation in over-anticoagulated patients, with faster decrease of INR value in patients carrying the G allele.

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.

Polymorphisms of matrix metalloproteinases in systolic heart failure: role on disease susceptibility, phenotypic characteristics, and prognosis.

BACKGROUND: The role of matrix metalloproteinases (MMPs) polymorphisms on heart failure (HF) susceptibility, phenotypic characteristics, and prognosis has been poorly explored. METHODS AND RESULTS: We studied 313 HF patients with left ventricular systolic dysfunction and 367 healthy control subjects. Genotyping of MMP-1 (-1607 1G/2G), MMP-3 (-1171 5A/6A), and MMP-9 (-1562 C/T) polymorphisms was performed by polymerase chain reaction. Allelic and genotypic frequencies of MMP-1, -3, and -9 were similar in HF patients and controls. MMP1 2G allele carriers were positively associated to ischemic etiology and history of myocardial infarction (all P values <.05). Patients were followed-up for a median of 40 months and 58 HF-related deaths occurred during this period. HF-related survival was significantly better in MMP1 2G allele carriers (71% versus 42% for 1G/1G patients, P = .002) and in MMP-3 6A allele carriers (70% versus 61% for 5A/5A patients, P = .064), particularly in non-ischemic patients (P = .039). MMP1 2G allele was independently associated to HF survival after adjustment for several other predictors of risk (hazard ratio 0.47, 95% confidence interval 0.27 to 0.82; P = .008). CONCLUSIONS: MMP-1, -3, and -9 polymorphisms were not associated to HF susceptibility. However, MMP1 2G allele carriers were related to a higher prevalence of ischemic etiology among patients with systolic HF and better HF-related prognosis.

Polymorphisms of the UCP2 gene are associated with proliferative diabetic retinopathy in patients with diabetes mellitus.

BACKGROUND AND OBJECTIVE: Uncoupling protein 2 (UCP2) plays a role in controlling reactive oxygen species (ROS) production by mitochondria. As ROS overproduction is related to diabetic retinopathy (DR), UCP2 gene polymorphisms might be involved in the development of this complication. We investigated whether the -866G/A (rs659366), Ala55Val (rs660339) and 45 bp insertion/deletion (Ins/Del) polymorphisms in the UCP2 gene might be associated with proliferative DR (PDR). DESIGN AND METHODS: In this case-control study, we analysed 501 type 2 diabetic patients (242 patients with PDR and 259 subjects without any degree of DR) and 196 type 1 diabetic patients (85 cases with PDR and 111 without DR). Haplotypes constructed from the combination of the three UCP2 polymorphisms were inferred using a Bayesian statistical method. RESULTS: In the type 2 diabetic group, multivariate analyses confirmed that the haplotype [A Val Ins] was an independent risk factor for PDR when present in one [adjusted odds ratio (aOR) = 2.12; P = 0.006], at least one (aOR = 2.75; P = 0.00001), or two copies (aOR = 5.30; P = 0.00001), suggesting an additive model of inheritance. Nevertheless, in type 1 diabetic patients, the association of this haplotype with PDR was confirmed only when it was present in at least one (aOR = 2.68; P = 0.014) or two copies (aOR = 6.02; P = 0.005). CONCLUSIONS: The haplotype [A Val Ins] seems to be an important risk factor associated with PDR in both type 2 and 1 diabetic groups.

Genetic polymorphisms of the adrenergic system and implantable cardioverter-defibrillator therapies in patients with heart failure.

AIMS: We investigated whether the combination of beta(1)-Gly389Arg and GNB3 C825T, two genetic polymorphisms strictly related to adrenergic system modulation, could act as predictors of appropriate therapies in patients with heart failure (HF) using implantable cardioverter-defibrillators (ICDs). METHODS AND RESULTS: Patients with HF and ICD implantation for primary and secondary prevention were studied. All ICD therapies were registered and classified as appropriate (secondary to ventricular tachycardia) or inappropriate (others). Genetic analysis was performed by polymerase chain reaction and restriction fragment length polymorphism methods. Seventy-three patients with mean left ventricular ejection fraction of 35 +/- 11% were evaluated. Overall, 35 ICD therapies occurred during follow-up in 31 (42.5%) patients. Twenty-four therapies (33%) were appropriate, and 11 (15%) were inappropriate. Individual analysis of each polymorphism only identified T825 carriers of GNB3 C825T as predictor of appropriate shocks. The combined presence of risk genotypes (Arg389 of the beta(1)-Gly389Arg and T825 of the GNB3 C825T) identified patients with higher risk of appropriate shocks. Patients with two at-risk genotypes had a survival rate free of appropriate shocks lower than those with none or only one of these markers (87 vs. 54%, respectively; log-rank statistic = 0.006). Using a Cox regression model, each at-risk genotype was associated with an increment of risk of appropriate ICD shocks (odds ratio = 3.9, 95% confidence interval of 1.3-12.0; P = 0.02). CONCLUSION: Genetic polymorphisms of the adrenergic system may help to identify HF patients who are more likely to receive appropriate ICD therapies. Further studies are necessary to determine the clinical applicability of these polymorphisms as predictors of arrhythmias.

Impact of beta1-adrenergic receptor polymorphisms on susceptibility to heart failure, arrhythmogenesis, prognosis, and response to beta-blocker therapy.

Beta1-adrenergic receptor polymorphisms have been implicated with inconsistent results in the pathogenesis, clinical presentation, and prognosis of patients with heart failure (HF). The impact of 2 functional polymorphisms (beta1-Arg389Gly and beta1-Ser49Gly) on HF susceptibility, arrhythmogenesis, and prognosis was evaluated in Brazilian outpatients. Genotyping at codons 389 and 49 was performed using polymerase chain reaction with restriction fragment length polymorphism analysis in 201 outpatients with systolic HF and 141 apparently healthy controls. Enrolled patients were followed up at the HF clinic, and vital status was evaluated using electronic hospital records, telephone contact, and a local death certificate database. Allele frequencies were similar between patients with HF and controls, with neither polymorphism related to HF susceptibility. The beta1-389Gly homozygotes had significantly less nonsustained ventricular tachycardia on Holter monitoring (17% vs 48% for Arg/Arg patients; p = 0.015) and improved HF-related survival, with no events after a median follow-up of 40 months (log-rank statistics = 0.025). The negative impact of beta1-389Arg allele on HF-related survival was substantially reduced using high-dose beta-blocker therapy (80% survival for high-dose vs 42% for low-dose beta blockers or nonusers; log-rank statistics = 0.0003). The beta1-Ser49Gly polymorphism was not associated with nonsustained ventricular tachycardia or HF prognosis. In conclusion, beta1-Arg389Gly and beta1-Ser49Gly polymorphisms had no influence on HF susceptibility. However, the Gly389 allele was associated with a lower prevalence of ventricular arrhythmias and better HF-related survival. A pharmacogenetic interaction is suggested because beta blockers were more effective in beta1-389Arg allele carriers.

Functional vascular endothelial growth factor -634G>C SNP is associated with proliferative diabetic retinopathy: a case-control study in a Brazilian population of European ancestry.

OBJECTIVE: The purpose of this study was to evaluate the effect of the single nucleotide polymorphism (SNP) -634G>C at the 5' regulatory region of the vascular endothelial growth factor (VEGF) in the risk of proliferative diabetic retinopathy (PDR) in the Brazilian population of European ancestry with type 2 diabetes. RESEARCH DESIGN AND METHODS: A case-control study was conducted in 501 type 2 diabetic patients of European ancestry. Patients underwent a standardized clinical, ophthalmological, and laboratory evaluation. Of these, 167 patients had PDR (case patients), and 334 were considered as control subjects (patients without PDR) for PDR. A reference population (110 individuals of European ancestry) was also evaluated. RESULTS: No evidence of association between -634G>C/VEGF and the presence of diabetic retinopathy or type 2 diabetes was observed (P > 0.05). However, CC homozygous for the SNP -634G>C was significantly more frequent in patients with PDR (37 of 167; 22.2%) than in the corresponding control group (40 of 334; 12%) in accordance with a recessive model (P = 0.003). This effect was further observed when creatinine, BMI, sex, duration of type 2 diabetes, HDL cholesterol, and systolic blood pressure were taken into account (odds ratio 1.9 [95% CI 1.01-3.79], P = 0.04). CONCLUSIONS: The presence of the allele -634C/VEGF in homozygosity is an independent risk factor for the development of PDR in type 2 diabetic patients of European ancestry.

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.

Relationship of p22phox C242T polymorphism with nephropathy in type 2 diabetic patients.

BACKGROUND: In this case-control study, we investigated the possible involvement of the p22phox C242T polymorphism in the development and progression of diabetic nephropathy (DN) in 535 Caucasian Brazilians with type 2 diabetes. We also evaluated the effects of the interaction of the C242T polymorphism with smoking and hypercholesterolemia on the susceptibility to nephropathy. METHODS: Genotype analysis was performed using polymerase chain reaction (PCR) followed by digestion with restriction enzyme. Logistic regression analysis was used to control for independent risk factors associated with nephropathy. RESULTS: The genotype frequencies in patients with overt DN (CC/CT/TT: 0.36/0.47/0.17) were not significantly different from those of diabetic individuals with normoalbuminuria (0.47/0.41/0.12) or microalbuminuria (0.42/0.48/0.10) (p=0.214). Likewise, there were no differences in the T allele frequency among patients with normoalbuminuria, microalbuminuria or overt DN (0.33, 0.34 and 0.40, respectively; p=0.111). However, the T allele was found to be more frequent among smokers with overt nephropathy (macroalbuminuria and/or in dialysis) than those who had normoalbuminuria (43 vs. 32%, p=0.045). The multiple logistic regression analysis confirmed that the CT+TT genotypes were independently associated with a higher risk of having overt nephropathy among smokers [odds ratio (OR)=6.76, 95% confidence interval (95% CI) 1.83-25.02]. CONCLUSIONS: Our study shows a gene-environment interaction associated with the increased risk of DN progression in Caucasian Brazilian smokers with type 2 diabetes. Further studies should be performed to clarify whether it exists, and to what extent there is a relationship between the p22phox C242T polymorphism and DN.

The -308G>a polymorphism of the TNF gene is associated with proliferative diabetic retinopathy in Caucasian Brazilians with type 2 diabetes.

PURPOSE: We tested the hypothesis that tumor necrosis factor (TNF) gene polymorphisms are associated with diabetic retinopathy (DR) in Caucasians with type 2 diabetes mellitus. METHODS: In a case-control study, the -238G>A (rs361525), -308G>A (rs1800629), and -857C>T (rs1799724) polymorphisms of the TNF gene were genotyped in 745 outpatients with type 2 diabetes, including 331 subjects without DR, 246 with nonproliferative DR (NPDR), and 168 with proliferative DR (PDR). RESULTS: Genotype and allele frequencies of the -238G>A, -308G>A, and -857C>T polymorphisms in subjects with NPDR were not significantly different from those of subjects without DR (P > 0.05 for all comparisons). However, the A allele of the -308G>A polymorphism was more frequent in subjects with PDR than in those with no DR (18.1% vs. 11.5%, corrected P = 0.035). Multivariate logistic regression analysis showed that the -308A allele was independently associated with an increased risk of PDR, under a dominant model (adjusted odds ratio [aOR], 1.82; 95% confidence interval [CI], 1.11-2.98). The combined analysis of the three polymorphisms also showed that haplotypes containing the -308A allele were associated with an increased risk of PDR (aOR, 2.36; 95% CI, 1.29-4.32). CONCLUSIONS: This study detected, for the first time to our knowledge, an independent association of the -308G>A polymorphism in the TNF gene with PDR in Caucasian Brazilians with type 2 diabetes. This finding suggests that TNF is a potential susceptibility gene for PDR.

Diabetic retinopathy in Euro-Brazilian type 2 diabetic patients: relationship with polymorphisms in the aldose reductase, the plasminogen activator inhibitor-1 and the methylenetetrahydrofolate reductase genes.

We investigated the relationship between diabetic retinopathy (DR) and three polymorphisms, C(-106)T in the aldose reductase (ALR2) gene, 4G/5G in the plasminogen activator inhibitor-1 (PAI-1) gene and C677T in the methylenetetrahydrofolate reductase (MTHFR) gene, in 210 Euro-Brazilian type 2 diabetic patients. Retinopathy was evaluated by funduscopic examination and genotype analysis was performed using the polymerase chain reaction and allele-specific restriction. Retinopathy was detected in 47% of the patients. There were no significant differences in allele or genotype distributions between patients with or without retinopathy for all polymorphisms. Thus, the three polymorphisms are not related to the presence of DR in Euro-Brazilian type 2 diabetic patients.

QRS widening rates and genetic polymorphisms of matrix metalloproteinases in a cohort of patients with chronic heart failure.

BACKGROUND: QRS duration is considered to be an indicator of adverse outcome in patients with heart failure (HF), and genetic polymorphisms may be involved in this conductivity impairment. We studied the prognostic impact of the QRS widening rate (QRS-WR) on patients with HF and the influence of the matrix metalloproteinases gene polymorphisms on the QRS-WR. METHODS: This prospective cohort study included 184 patients with left ventricular (LV) systolic dysfunction (LV ejection fraction [LVEF] < 45%). The QRS-WR was calculated as the difference between 2 electrocardiogram assessments (in ms) divided by the time elapsed between each evaluation (months). The MMP-1 -1607 1G/2G, MMP-2 -790G/T and -1575G/A, MMP-3 -1171 5A/6A, MMP-9 -1562 C/T and R279Q, and MMP-12 -82A/G polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Patients were predominantly white (68%) men (67%) in New York Heart Association functional classes I and II (77%). Patients with HF with a QRS-WR ≥ 0.5 ms/month had more HF-related deaths and more combined clinical events than those with a QRS-WR < 0.5 ms/month (P = 0.03 and P = 0.01, respectively). After adjusting for other covariates, the QRS-WR remained an independent predictor of combined clinical events (hazard ratio, 1.6; 95% confidence interval, 1.1-2.5; P = 0.02). The MMP-1 2G2G genotype was associated with nearly a 2-fold increase in QRS-WR (P = 0.03). Conversely, patients with the MMP-3 5A5A genotype and a nonischemic cause of HF were protected against QRS enlargement (P = 0.03). CONCLUSIONS: QRS-WR retains prognostic value in patients with chronic HF receiving guideline-based pharmacologic treatment. MMP gene polymorphisms can influence the rate of QRS enlargement over time.

An analysis of the global expression of microRNAs in an experimental model of physiological left ventricular hypertrophy.

BACKGROUND: MicroRNAs (miRs) are a class of small non-coding RNAs that regulate gene expression. Studies of transgenic mouse models have indicated that deregulation of a single miR can induce pathological cardiac hypertrophy and cardiac failure. The roles of miRs in the genesis of physiological left ventricular hypertrophy (LVH), however, are not well understood. OBJECTIVE: To evaluate the global miR expression in an experimental model of exercise-induced LVH. METHODS: Male Balb/c mice were divided into sedentary (SED) and exercise (EXE) groups. Voluntary exercise was performed on an odometer-monitored metal wheels for 35 days. Various tests were performed after 7 and 35 days of training, including a transthoracic echocardiography, a maximal exercise test, a miR microarray (miRBase v.16) and qRT-PCR analysis. RESULTS: The ratio between the left ventricular weight and body weight was increased by 7% in the EXE group at day 7 (p<0.01) and by 11% at day 35 of training (p<0.001). After 7 days of training, the microarray identified 35 miRs that were differentially expressed between the two groups: 20 were up-regulated and 15 were down-regulated in the EXE group compared with the SED group (p = 0.01). At day 35 of training, 25 miRs were differentially expressed: 15 were up-regulated and 10 were decreased in the EXE animals compared with the SED animals (p<0.01). The qRT-PCR analysis demonstrated an increase in miR-150 levels after 35 days and a decrease in miR-26b, miR-27a and miR-143 after 7 days of voluntary exercise. CONCLUSIONS: We have identified new miRs that can modulate physiological cardiac hypertrophy, particularly miR-26b, -150, -27a and -143. Our data also indicate that previously established regulatory gene pathways involved in pathological LVH are not changed in physiological LVH.

Relationship of endothelial nitric oxide synthase (eNOS) gene polymorphisms with diabetic retinopathy in Caucasians with type 2 diabetes.

BACKGROUND: Nitric oxide synthesized by endothelial nitric oxide synthase (eNOS) plays a key role in the regulation of endothelial function, and controversial results regarding the association of eNOS gene polymorphisms with diabetic complications have been reported. MATERIALS AND METHODS: In this case-control study, the relationship of the -786T/C, the VNTR intron 4 a/b and the 894G/T (Glu298Asp) polymorphisms in the eNOS gene with the presence or severity of diabetic retinopathy was analyzed in 630 Caucasian-Brazilians with type 2 diabetes (434 with and 196 without diabetic retinopathy). Genotyping of eNOS polymorphisms was carried out using the PCR or PCR-RFLP method, and haplotype frequencies were estimated using a Bayesian method. RESULTS: Genotype and allele frequencies in patients with any degree of diabetic retinopathy or proliferative diabetic retinopathy were not significantly different from those of patients without this complication for all eNOS polymorphisms. Likewise, there were no differences in haplotype frequencies among diabetic patients with or without diabetic retinopathy (p values > 0.05 for all comparisons). CONCLUSION: Our findings do not support the hypothesis that the -786T/C, the VNTR intron 4 a/b and the 894G/T (Glu298Asp) polymorphisms in the eNOS gene play a role in the pathogenesis of diabetic retinopathy in type 2 diabetes.

Association of eNOS gene polymorphisms with renal disease in Caucasians with type 2 diabetes.

AIM: In this study we investigated if the -786T>C, the VNTR intron 4 a/b and the 894G>T (Glu298Asp) polymorphisms in the eNOS gene were associated with renal disease in 617 type 2 diabetic Caucasian-Brazilians. These polymorphisms were also examined in 100 Caucasian healthy blood donors. METHODS: Genotyping of eNOS polymorphisms was performed by PCR or PCR-RFLP and haplotype frequencies were estimated using a Bayesian method. Logistic regression analysis was done to test for association of eNOS polymorphisms with susceptibility to renal involvement (microalbuminuria, macroalbuminuria or end-stage renal disease). This analysis was carried out assuming three different genetic models for the minor allele, adjusting for possible effect modifiers. RESULTS: Genotype and allele frequencies in patients with renal disease were not significantly different from those of patients with normoalbuminuria and healthy blood donors for all eNOS polymorphisms. Likewise, there were no differences in haplotype frequencies among healthy blood donors and type 2 diabetic patients with or without renal involvement (P>0.05 for all comparisons). CONCLUSION: No associations between the -786T>C, the VNTR intron 4 a/b and the 894G>T (Glu298Asp) polymorphisms in the eNOS gene and renal disease were observed in type 2 diabetic Caucasian-Brazilians.