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

Molecular Mechanisms and Therapeutic Implications of Endothelial Dysfunction in Patients with Heart Failure

Heart failure is a complex medical syndrome that is attributed to a number of risk factors; nevertheless, its clinical presentation is quite similar among the different etiologies. Heart failure displays a rapidly increasing prevalence due to the aging of the population and the success of medical treatment and devices. The pathophysiology of heart failure comprises several mechanisms, such as activation of neurohormonal systems, oxidative stress, dysfunctional calcium handling, impaired energy utilization, mitochondrial dysfunction, and inflammation, which are also implicated in the development of endothelial dysfunction. Heart failure with reduced ejection fraction is usually the result of myocardial loss, which progressively ends in myocardial remodeling. On the other hand, heart failure with preserved ejection fraction is common in patients with comorbidities such as diabetes mellitus, obesity, and hypertension, which trigger the creation of a micro-environment of chronic, ongoing inflammation. Interestingly, endothelial dysfunction of both peripheral vessels and coronary epicardial vessels and microcirculation is a common characteristic of both categories of heart failure and has been associated with worse cardiovascular outcomes. Indeed, exercise training and several heart failure drug categories display favorable effects against endothelial dysfunction apart from their established direct myocardial benefit.

Association of eNOS and ACE gene polymorphisms as a genetic risk factor in gestational diabetes in Iranian women

Background

Gestational diabetes mellitus (GDM) is the most popular metabolic disease during pregnancy. The aim of the present study was to investigate any possible association between eNOS Glu298Asp and ACE I/D gene polymorphisms and the risk of GDM in a group of Iranian pregnant women.

Methods

In this case-control study 204 pregnant women were recruited (94 cases and 110 controls). Genomic DNA was isolated from whole blood and genotyping was performed by the Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR- RFLP) and only PCR for eNOS and ACE polymorphisms respectively.

Results

Frequencies of GT and TT genotype of eNOS polymorphism among women with and without GDM were 67.90% vs. 74.47 and 7.41% vs. 8.51% respectively (P = 0.4). Corresponding figures for DD genotype of ACE polymorphism among GDM patients was more than that in healthy women (51.65% vs. 63.81% respectively). Conversely, ACE heterozygote genotype was more common in diabetic women (35.16% vs. 26.67% respectively). Although these differences were not statistically significant (P = 0.2).

Conclusions

Our study showed that there is no association between the presence of eNOS and ACE gene polymorphisms and developing gestational diabetes mellitus among pregnant women in our population. Further longitudinal and multicenter studies should be carried out to assess the exact metabolic effects of these polymorphisms.

Heart failure and endothelial nitric oxide synthase G894T gene polymorphism frequency variations within ancestries

The G894T polymorphism in endothelial nitric oxide synthase enzyme gene plays an important role in heart failure (HF) and its frequency varies among populations. We investigated this association in highly admixed samples in terms of ancestry. The cohort included 210 HF patients and 106 healthy individuals. Self-reported race and NYHA class were analyzed for HF patients. G894T polymorphism was analyzed by polymerase chain reaction (PCR) and by restriction fragment length polymorphism technique. Ancestry was estimated using a PCR reaction containing 46 autosomal ancestry informative markers and an analysis by capillary electrophoresis. The GG homozygous genotype had a higher frequency in HF patients (63.8%) than in healthy individuals (48.1%), showing an increased chance (odds ratio 1.90, 95% confidence interval 1.18-3.05). The ancestry profiles in patients and controls were similar, with a major European contribution (57.1% and 63.2%), followed by African (30.2% and 24.0%) and Native American (12.7% and 12.8%), without a significant difference between both samples (p = 0.28). The GG genotype is associated to HF prognosis, and this association remains present in highly admixed sample groups.

The Endothelial Nitric Oxide Synthase (NOS3-786T>C) Genetic Polymorphism in Chronic Heart Failure: Effects of Mutant -786C allele on Long-term Mortality

BACKGROUND

Nitric oxide plays an important role in the regulation of basal vascular tone and cardiac myocyte function. We investigated the NOS3-786T>C polymorphism in chronic heart failure (CHF) and its effects on long-term mortality.

METHODS

Ninety-one patients with CHF who were referred to the Department of Cardiology of Siyami Ersek Cardiovascular and Thoracic Surgery Center for cardiopulmonary exercise testing between April 2001 and January 2004 and 30 controls were enrolled in this study. Patient were followed prospectively for a period of 1 to 12 years.

RESULTS

Patients and controls were divided into three groups: TT, TC and CC, according to their NOS3-786T>C polymorphism. We noted that there was no significant difference in the genotype distribution between patients and controls. There was also no significant difference in endothelial nitric oxide synthase (eNOS) gene polymorphism between ischemic HF and nonischemic HF. During the follow-up period, 61 (67%) deaths occurred. The nonsurvivor group had lower left ventricular ejection fraction (LVEF) (p = 0.01), reduced peak oxygen consumption (p = 0.04) and were of older age (p = 0.001). Age, LVEF, peak oxygen consumption and genotype were found to be predictors of mortality (p < 0.05). Additionally, mortality was significantly increased in -786CC genotype patients compared to TT genotype patients (hazard ratio = 2.2; p = 0.03). By multivariate analysis, age and eNOS genotype were determined to be significant independent predictors of death. Additionally, Kaplan-Meier analysis confirmed that homozygote -786C genotype was associated with an increased risk of death (χ2 = 4.6, p = 0.03).

CONCLUSIONS

Our findings showed that the NOS3-786T>C polymorphism was associated with an increased risk of mortality in patients with CHF.

Pro-atherogenic mediators and subclinical atherogenesis are related to epicardial adipose tissue thickness in patients with cardiovascular risk

Objective

To evaluate the relationship between pro-atherogenic biomarkers and epicardial adipose tissue (EAT) thickness in patients with cardiovascular risk factors.

Methods

Plasma nitric oxide (NO), soluble intercellular adhesion molecule-1 and malondialdehyde (MDA) levels, EAT thickness, flow-mediated dilation (FMD) and carotid intima media thickness (CIMT) were determined in patients aged >18 years who were referred for echocardiography for heart ischemia or non-ischemic diseases. Cardiovascular risk factors (Framingham score [FS] ≥ 20) were weighted.

Results

Hypertension, dyslipidaemia and type 2 diabetes mellitus were prevalent (≥55% of 40 patients). Patients with FS ≥ 20 (n = 21) showed significantly higher EAT and CIMT values. Globally, MDA, CIMT, age, waist circumference, high-density lipoprotein cholesterol (HDL-C) and FS were associated with EAT thickness. EAT was significantly associated with NO in patients with FS ≥ 20. Significant differences in EAT thickness were found between patients stratified by NO value, FMD, age, smoking status, dyslipidaemia, type 2 diabetes mellitus and FS. An EAT-associated atherogenic risk (CIMT ≥ 1 mm) model was statistically significant when MDA and type 2 diabetes mellitus were included.

Conclusion

EAT thickness was associated with MDA, CIMT, age, waist circumference, HDL-C and FS globally, but with NO only in patients with FS≥20. EAT may be used to identify vascular damage stage, possibly influenced by MDA and type 2 diabetes mellitus.

Genetics of systolic and diastolic heart failure

Heart failure accounts for a significant portion of heart diseases. Molecular mechanisms gradually emerge that participate in pathways leading to left ventricular dysfunction in common systolic heart failure (SHF) and diastolic heart failure (DHF). A human genome-wide association study (GWAS) identified two markers for SHF and no GWAS on DHF has been documented. However, genetic analyses in rat models of SHF and DHF have begun to unravel the genetic components known as quantitative trait loci (QTLs) initiating systolic and diastolic function. A QTL for systolic function was detected and the gene responsible for it is identified to be that encoding the soluble epoxide hydrolase. Diastolic function is determined by multiple QTLs and the Ccl2/monocyte chemotactic protein gene is the strongest candidate. An amelioration on diastolic dysfunction is merely transient from changing such a single QTL accompanied by a blood pressure reduction. A long-term protection can be achieved only via combining alleles of several QTLs. Thus, distinct genes in synergy are involved in physiological mechanisms durably ameliorating or reversing diastolic dysfunction. These data lay the foundation for identifying causal genes responsible for individual diastolic function QTLs and the essential combination of them to attain a permanent protection against diastolic dysfunction, and consequently will facilitate the elucidation of pathophysiological mechanisms underlying hypertensive diastolic dysfunction. Novel pathways triggering systolic and diastolic dysfunction have emerged that will likely provide new diagnostic tools, innovative therapeutic targets and strategies in reducing, curing and even reversing SHF and DHF.

Polymorphism of Nitric Oxide Synthase 1 Affects the Clinical Phenotypes of Ischemic Stroke in Korean Population

Objective

To investigate whether four single nucleotide polymorphisms (SNPs) rs2293054 [Ile734Ile], rs1047735 [His902His], rs2293044 [Val1353Val], rs2682826 (3'UTR) of nitric oxide synthase 1 (NOS1) are associated with the development and clinical phenotypes of ischemic stroke.

Methods

We enrolled 120 ischemic stroke patients and 314 control subjects. Ischemic stroke patients were divided into subgroups according to the scores of the National Institutes of Health Stroke Survey (NIHSS, <6 and ≥6) and Modified Barthel Index (MBI, <60 and ≥60). SNPStats, SNPAnalyzer, and HelixTree programs were used to calculate odds ratios (ORs), 95% confidence intervals (CIs), and p-values. Multiple logistic regression models were performed to analyze genetic data.

Results

No SNPs of the NOS1 gene were found to be associated with ischemic stroke. However, in an analysis of clinical phenotypes, we found that rs2293054 was associated with the NIHSS scores of ischemic stroke patients in codominant (p=0.019), dominant (p=0.007), overdominant (p=0.033), and log-additive (p=0.0048) models. Also, rs2682826 revealed a significant association in the recessive model (p=0.034). In allele frequency analysis, we also found that the T alleles of rs2293054 were associated with lower NIHSS scores (p=0.007). Respectively, rs2293054 had a significant association in the MBI scores of ischemic stroke in codominant (p=0.038), dominant (p=0.031), overdominant (p=0.045), and log-additive (p=0.04) models.

Conclusion

These results suggest that NOS1 may be related to the clinical phenotypes of ischemic stroke in Korean population.

Thalidomide embryopathy: Follow-up of cases born between 1959 and 2010

BACKGROUND

Thalidomide is a known teratogen and it is estimated that more than ten thousand babies were affected by thalidomide embryopathy (TE), which is characterized mainly by limb defects, but can involve many organs and systems. Most people with TE were only evaluated at birth and it is not well established if thalidomide exposure during embryonic development leads to later effects. We analyzed the clinical history of adults with TE to better understand this gap in the clinical findings of TE.

METHODS

Brazilian individuals with TE were invited to answer a clinical questionnaire which considered family history, social information, medical history, and current clinical and psychological health status. A clinical examination was also performed, including on the infant subjects to evaluate congenital anomalies. The characterization of the features was analyzed using descriptive statistics and Chi-square or Fisher's exact test.

RESULTS

The congenital anomalies caused by thalidomide were reviewed in 28 Brazilian individuals, and the questionnaire was applied to the 23 adult subjects with TE (aged 19 to 55). Progressive deafness and dental loss were reported. From the comparison of TE individuals with the general Brazilian population, the early onset of cardiovascular diseases (p = 0.009) and a higher frequency of psychological disorders (p = 0.011) were observed.

CONCLUSION

Although there is no sufficient evidence that thalidomide exposure caused or worsened the described events, this approach helps to better understand the TE phenotype, improves the clinical diagnosis, and can lead to adequate health support for these individuals.

Genetic prediction of heart failure incidence, prognosis and beta-blocker response

Heart failure (HF) is a widespread syndrome due to left ventricular dysfunction with high mortality, morbidity and health-care costs. Beta-blockers, together with diuretics and ACE-inhibitors or angiotensin receptor blockers, are a cornerstone of HF therapy, as they reduce mortality and morbidity. Nevertheless, their efficacy varies among patients, and genetics is likely to be one of the modifying factors. In this article, literature on the role of candidate genes on the development of HF, its prognosis and pharmacogenomics of β-blockers in patients with HF is reviewed. The available findings do not support, at the present time, a role for genetic tests in the treatment of HF. More large-scale genome-wide studies with adequate methodology and statistical analysis are required before considering genetic tailoring of HF therapy in patients with systolic HF.