Genetic predisposition in patients with hypertension and normal ejection fraction to oxidative stress

Superoxide Dismutase Gene Polymorphism is Associated With Ischemic Stroke Risk in the China Dali Region Han Population

BACKGROUND

Stroke is a serious cardiovascular disease, a major cause of disability and death in both developed and developing countries. Superoxide dismutases (SODs) are enzymes that catalyze the breakdown of superoxide into oxygen and hydrogen peroxide and play a key role in the antioxidant response. This study explored the relationship between single-nucleotide polymorphisms (SNPs) in SOD genes and the risk of ischemic stroke (IS) in the Chinese Han population of Dali City.

METHODS

For this case-control study, the authors enrolled 144 patients who had an IS and 128 healthy controls. The SNPs rs17880487 and rs80265967 of the SOD1 gene, rs4880 and rs2842960 of the SOD2 gene, and rs2695232 and rs7655372 of the SOD3 gene were detected through TaqMan polymerase chain reaction. Genotypes and allele frequencies of the 2 groups were compared. Odds ratio and 95% confidence intervals were calculated by unconditional logistic regression, and environmental factors were corrected with multivariate logistic regression analysis.

RESULTS

Rs7655372 of SOD3 was associated with a significantly increased risk of IS. Moreover, the A and GA genotypes of SNP rs7655372 were associated with increased risk of IS, whereas the A and GA genotypes were risk factors for IS. Furthermore, multivariate logistic regression analysis showed that the rs7655372 GA genotype is the independent risk factor for IS.

CONCLUSION

The SOD3 gene rs7655372 locus polymorphism is a risk factor for IS in the Dali region.

Factors associated with elevated plasma phenylalanine in patients with heart failure

Elevated phenylalanine has been observed in patients with advanced heart failure (HF) and in community cohorts at risk of HF, and has been shown to have prognostic value. This study aimed to explore the factors associated with elevated phenylalanine in HF patients. Mass spectrometry was performed on blood from 669 participants, including 75 normal controls and 594 HF patients (stages A, B, and C). We measured phenylalanine and associated degradation products on the catecholamine pathway, C-reactive protein, valerylcarnitine, methionine sulfoxide, estimated glomerular filtration rate (eGFR), and B-type natriuretic peptide. Longitudinal analysis was conducted on 61 stage C HF patients who had recovered systolic function after 1 year. Phenylalanine and tyrosine levels increased from normal through stages A, B and C. Cross-sectional analysis in patients at stage C showed that phenylalanine levels were related to total bilirubin, eGFR, valerylcarnitine, methionine sulfoxide, C-reactive protein, and male gender. Longitudinal analysis in the patients at stage C with recovered systolic function after 1 year revealed that phenylalanine, tyrosine, methionine sulfoxide, total bilirubin, and C-reactive protein levels significantly decreased from baseline to 12 months. Based on a generalized estimating equations analysis model with time interaction considered, the only significant factor associated with changes in phenylalanine was changes in C-reactive protein concentrations from baseline to 12 months [B (coefficient) = 0.81, P < 0.001] after adjusting for methionine sulfoxide and total bilirubin levels. In conclusion, phenylalanine levels respond sensitively to HF improvement. Our findings suggest that inflammation plays a pivotal role in the elevation of phenylalanine levels in patients with HF.

Clinical Significance of Arterial Velocity Pulse Index in Patients With Stage B Heart Failure With Preserved Ejection Fraction

Background

In clinical settings, the arterial velocity pulse index (AVI) is explored as a novel marker of atherosclerosis using pulse wave analysis; however, data regarding the correlations between AVI and heart failure (HF) are limited. This study aimed to elucidate the clinical significance of AVI in patients with stage B HF with preserved ejection fraction (HFpEF).

Methods

In this cross-sectional study, 345 patients with stage B HFpEF (no symptoms despite evidence of cardiac structural or functional impairment, and left ventricular ejection fraction which is estimated by echocardiography ≥ 50%) were enrolled. Patients with a history of HF hospitalization were excluded. The AVI was measured using a commercial device, and associations between AVI and various clinical parameters were examined.

Results

Significant correlations between AVI and various clinical parameters, such as E/e' as a maker of left ventricular diastolic function (r = 0.35; P < 0.001), high-sensitivity cardiac troponin T levels as a marker of myocardial injury (r = 0.47; P < 0.001), reactive oxygen metabolite levels as an oxidative stress marker (r = 0.31; P < 0.001), urinary albumin concentration as a marker of kidney function (r = 0.34; P < 0.001) and calf circumference as a marker of muscle mass volume (r = -0.42; P < 0.001) were observed. Furthermore, multiple regression analyses revealed that these clinical parameters were selected as independent variables when AVI was used as a subordinate factor.

Conclusions

This study shows that AVI might be a determining factor for prognosis in patients with stage B HFpEF. Nevertheless, further comprehensive prospective studies, including intervention therapies, are warranted to validate the findings of this study.

Heart failure with preserved ejection fraction in hypertension

PURPOSE OF REVIEW

Hypertension is the most prevalent risk factor in heart failure with preserved ejection fraction (HFpEF) and plays a key role in the disease. The continued lack of effective therapies to improve outcomes in HFpEF underscores the knowledge gaps regarding the pathophysiology of HFpEF. This review builds on fundamental concepts in pressure overload-induced left ventricular modeling, and summarizes recent knowledge gained regarding the mechanisms underlying the transition from hypertensive heart disease to HFpEF.

RECENT FINDINGS

The pathophysiology of hypertensive HFpEF extends beyond the development of left ventricular hypertrophy and diastolic dysfunction to myocardial contractile dysfunction, beyond left atrial structural dilatation to left atrial functional decline, beyond macrovascular stiffening to microvascular dysfunction, beyond central cardiac triggers to systemic endothelial inflammation, beyond fibrosis to titin changes, and beyond collagen deposition to qualitative changes in collagen. The central paradigm involves a systemic proinflammatory state triggering a downstream cascade of cardiac microvascular endothelial activation, oxidative stress, and abnormal myocardial cyclic guanosine monophosphate signaling, leading to microvascular rarefaction, chronic ischemia, fibrosis and progression to HFpEF.

SUMMARY

Recent advances have provided insights into the pathophysiology of HFpEF in hypertension. Such knowledge provides novel opportunities for therapeutic strategies in the treatment of hypertensive HFpEF.

Circulating Biomarkers in Heart Failure

Biological markers have served for diagnosis, risk stratification and guided therapy of heart failure (HF). Our knowledge regarding abilities of biomarkers to relate to several pathways of HF pathogenesis and reflect clinical worsening or improvement in the disease is steadily expanding. Although there are numerous clinical guidelines, which clearly diagnosis, prevention and evidence-based treatment of HF, a strategy regarding exclusion of HF, as well as risk stratification of HF, nature evolution of disease is not well established and requires more development. The aim of the chapter is to discuss a role of biomarker-based approaches for more accurate diagnosis, in-depth risk stratification and individual targeting in treatment of patients with HF.