Polymorphisms of antioxidant enzymes, blood pressure and risk of hypertension

Sour Tamarind Is More Antihypertensive than the Sweeter One, as Evidenced by In Vivo Biochemical Indexes, Ligand-Protein Interactions, Multitarget Interactions, and Molecular Dynamic Simulation

This research investigated the antihypertensive effects of tamarind products and compared their potentials based on an animal model's data verified by molecular docking, multitarget interactions, and dynamic simulation assays. GC-MS-characterized tamarind products were administered to cholesterol-induced hypertensive albino rat models. The two-week-intervened animals were dissected to collect their serum and organs and respectively subjected to analyses of their hypertension-linked markers and tissue architectures. The lead biometabolites of tamarinds interacted with eight target receptors in the molecular docking and dynamic simulation studies and with multitarget in the network pharmacological analyses. The results show that the serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), C-reactive protein (CRP), troponin I, and lipid profiles were maximally reinstated by the phenolic-enriched ripened sour tamarind extract compared to the sweet one, but the seed extracts had a smaller influence. Among the tamarind's biometabolites, ϒ-sitosterol was found to be the best ligand to interact with the guanylate cyclase receptor, displaying the best drug-likeliness with the highest binding energy, -9.3 Kcal. A multitargeted interaction-based degree algorithm and a phylogenetic tree of pathways showed that the NR3C1, REN, PPARG, and CYP11B1 hub genes were consistently modulated by ϒ-sitosterol to reduce hypertension and related risk factors. The dynamic simulation study showed that the P-RMSD values of ϒ-sitosterol-guanylate cyclase were stable between 75.00 and 100.00 ns at the binding pocket. The findings demonstrate that ripened sour tamarind extract may be a prospective antihypertensive nutraceutical or supplement target affirmed through advanced preclinical and clinical studies.

Modulation of NRF2/KEAP1 Signaling in Preeclampsia

Placentation is a key and tightly regulated process that ensures the normal development of the placenta and fetal growth. Preeclampsia (PE) is a hypertensive pregnancy-related disorder involving about 5-8% of all pregnancies and clinically characterized by de novo maternal hypertension and proteinuria. In addition, PE pregnancies are also characterized by increased oxidative stress and inflammation. The NRF2/KEAP1 signaling pathway plays an important role in protecting cells against oxidative damage due to increased reactive oxygen species (ROS) levels. ROS activate NRF2, allowing its binding to the antioxidant response element (ARE) region present in the promoter of several antioxidant genes such as heme oxygenase, catalase, glutathione peroxidase and superoxide dismutase that neutralize ROS, protecting cells against oxidative stress damages. In this review, we analyze the current literature regarding the role of the NRF2/KEAP1 pathway in preeclamptic pregnancies, discussing the main cellular modulators of this pathway. Moreover, we also discuss the main natural and synthetic compounds that can regulate this pathway in in vivo and in vitro models.

Role of thioredoxin-interacting protein in mediating endothelial dysfunction in hypertension

Excessive oxidative stress is a major causative factor of endothelial dysfunction in hypertension. As an endogenous pro-oxidant, thioredoxin-interacting protein (TXNIP) contributes to oxidative damage in various tissues. The present study aimed to investigate the role of TXNIP in mediating endothelial dysfunction in hypertension. In vivo, an experimental model of acquired hypertension was established with two-kidney, one-clip (2K1C) surgery. The expression of TXNIP in the vascular endothelial cells of multiple vessels was significantly increased in hypertensive rats compared with sham-operated rats. Resveratrol, a TXNIP inhibitor, suppressed vascular oxidative damage and increased the expression and activity of eNOS in the aorta of hypertensive rats. Notably, impaired endothelium-dependent vasodilation was effectively improved by TXNIP inhibition in hypertensive rats. In vitro, we observed that Ang II increased the expression of TXNIP in primary human aortic endothelial cells (HAECs) and that TXNIP knockdown by RNA interference alleviated cellular oxidative stress damage and mitigated the impaired eNOS activation and intracellular nitric oxide (NO) production observed in Ang II-treated HAECs. However, inhibiting thioredoxin (TRX) with PX-12 completely blunted the protective effect of silencing TXNIP. In addition, TXNIP knockdown facilitated TRX expression and promoted TRX nuclear translocation to further activate AP1 and REF1. TRX overexpression exhibited favorable effects on eNOS/NO homeostasis in Ang II-treated HAECs. Thus, TXNIP contributes to oxidative stress and endothelial dysfunction in hypertension, and these effects are dependent on the antioxidant capacity of TRX, suggesting that targeting TXNIP may be a novel strategy for antihypertensive therapy.

Genetic Variations on Redox Control in Cardiometabolic Diseases: The Role of Nrf2

The transcription factor Nrf2 is a master regulator of multiple cytoprotective genes that maintain redox homeostasis and exert anti-inflammatory functions. The Nrf2-Keap1 signaling pathway is a paramount target of many cardioprotective strategies, because redox homeostasis is essential in cardiovascular health. Nrf2 gene variations, including single nucleotide polymorphisms (SNPs), are correlated with cardiometabolic diseases and drug responses. SNPs of Nrf2, KEAP1, and other related genes can impair the transcriptional activation or the activity of the resulting protein, exerting differential susceptibility to cardiometabolic disease progression and prevalence. Further understanding of the implications of Nrf2 polymorphisms on basic cellular processes involved in cardiometabolic diseases progression and prevalence will be helpful to establish more accurate protective strategies. This review provides insight into the association between the polymorphisms of Nrf2-related genes with cardiometabolic diseases. We also briefly describe that SNPs of Nrf2-related genes are potential modifiers of the pharmacokinetics that contribute to the inter-individual variability.

Status of Catalase, Glutathione Peroxidase, Glutathione S-Transferase, and Myeloperoxidase Gene Polymorphisms in Beta-Thalassemia Major Patients to Assess Oxidative Injury and Its Association with Enzyme Activities

Beta-thalassemic patients require regular blood transfusion to sustain their life which leads to iron overload and causes oxidative stress. The aim of this study was to investigate the status of variants in genes including GSTM1, GSTT1 (null/present), CT-262 (C > T) and CT-89 (A > T), glutathione peroxidase (GPx), and myeloperoxidase (MPO). The genotype studies were conducted with 200 thalassemia major (TM) patients and 200 healthy controls. Genotyping of GST gene was performed by multiplex polymerase chain reaction (PCR), whereas for CT, GPx and MPO genesvariants PCR- restriction fragment length polymorphism technique used. However, the enzyme activities were measured only in the patients group to assess the association with the genotypes. All enzyme estimations were performed by ELISA. We observed higher frequency of GSTT1 null, CT-89 (A > T), GPx1 198 (C > T) and MPO-463 (G > A) polymorphisms in TM patient than healthy controls. However, CT-262 (C > T) polymorphism was not found to be statistically significantly different between patients and controls. Our results suggest that frequency of null allele of glutathione-S-transferase is significantly high among TM patients. The other alleles CT-89 (A > T), GPx1 198 (C > T), and MPO-463 (G > A) are linked to decreased CT, GPX, and MPO enzyme activities.

Superoxide Dismutase Administration: A Review of Proposed Human Uses

Superoxide dismutases (SODs) are metalloenzymes that play a major role in antioxidant defense against oxidative stress in the body. SOD supplementation may therefore trigger the endogenous antioxidant machinery for the neutralization of free-radical excess and be used in a variety of pathological settings. This paper aimed to provide an extensive review of the possible uses of SODs in a range of pathological settings, as well as describe the current pitfalls and the delivery strategies that are in development to solve bioavailability issues. We carried out a PubMed query, using the keywords "SOD", "SOD mimetics", "SOD supplementation", which included papers published in the English language, between 2012 and 2020, on the potential therapeutic applications of SODs, including detoxification strategies. As highlighted in this paper, it can be argued that the generic antioxidant effects of SODs are beneficial under all tested conditions, from ocular and cardiovascular diseases to neurodegenerative disorders and metabolic diseases, including diabetes and its complications and obesity. However, it must be underlined that clinical evidence for its efficacy is limited and consequently, this efficacy is currently far from being demonstrated.

Nutrition, Bioenergetics, and Metabolic Syndrome

According to the World Health Organization (WHO), the global nutrition report shows that whilst part of the world’s population starves, the other part suffers from obesity and associated complications. A balanced diet counterparts these extreme conditions with the proper proportion, composition, quantity, and presence of macronutrients, micronutrients, and bioactive compounds. However, little is known on the way these components exert any influence on our health. These nutrients aiming to feed our bodies, our tissues, and our cells, first need to reach mitochondria, where they are decomposed into CO₂ and H₂O to obtain energy. Mitochondria are the powerhouse of the cell and mainly responsible for nutrients metabolism, but they are also the main source of oxidative stress and cell death by apoptosis. Unappropriated nutrients may support mitochondrial to become the Trojan horse in the cell. This review aims to provide an approach to the role that some nutrients exert on mitochondria as a major contributor to high prevalent Western conditions including metabolic syndrome (MetS), a constellation of pathologic conditions which promotes type II diabetes and cardiovascular risk. Clinical and experimental data extracted from in vitro animal and cell models further demonstrated in patients, support the idea that a balanced diet, in a healthy lifestyle context, promotes proper bioenergetic and mitochondrial function, becoming the best medicine to prevent the onset and progression of MetS. Any advance in the prevention and management of these prevalent complications help to face these challenging global health problems, by ameliorating the quality of life of patients and reducing the associated sociosanitary burden.

Association between serum liver enzymes and hypertension: a cross-sectional study in Bangladeshi adults

BACKGROUND

Hypertension is a major contributing factor to cardiovascular disease and is a leading cause of death in the world. The association between hepatic enzymes and hypertension has been reported in limited studies and the findings are inconsistent; data from Bangladeshi adults are not available yet. This study was conducted to estimate the prevalence of elevated liver enzymes and evaluate the association of elevated liver enzymes with hypertension in Bangladeshi adults.

METHODS

In this cross-sectional study, 302 blood samples were collected from adult participants and analyzed the serum concentrations of alanine and aspartate aminotransferase (ALT, AST), alkaline phosphatase (ALP), and γ-glutamyltransferase (GGT) and other markers related to hypertension. Hypertension was defined as resting SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg. Associations between elevated liver enzymes and hypertension were evaluated by multinomial logistic regression.

RESULTS

The mean concentrations of serum ALT, AST and GGT were significantly higher in the hypertensive group compared to the normotensive group (p < 0.01, p < 0.01 and p < 0.001, respectively). Overall, 49.2% of subjects in the hypertensive group and 38.1% of individuals in the normotensive group had at least one or more elevated liver enzymes. The prevalence of elevated ALT, AST, and GGT was significantly higher among participants in the hypertensive group compared to the normotensive group (p < 0.01, p < 0.01 and p < 0.001, respectively). An increasing trend for elevated liver enzymes was observed with increasing blood pressure. Serum ALT and GGT showed an independent relationship with hypertension.

CONCLUSIONS

The prevalence of elevated liver enzymes was higher in hypertensive individuals. Increased serum ALT and GGT activities were positively associated with hypertension in Bangladeshi adults.

Association of combined genetic variations in SOD3, GPX3, PON1, and GSTT1 with hypertension and severity of coronary artery disease

Oxidative stress plays a critical role in the pathophysiology of hypertension (HT) and the progression of atherosclerotic coronary artery disease (CAD). Genetic variations in superoxide dismutase (SOD), glutathione peroxidase 3 (GPX3), paraoxonase 1 (PON1) and glutathione S-transferase theta 1 (GSTT1) may modulate their gene functions, affecting protein functions. These changes could have an impact on the pathogenesis of HT and progression of CAD. The present study investigated the associations of individual and combined antioxidant-related gene polymorphisms with the incidence of HT and severity of CAD. Two study populations were enrolled. The HT-associated study comprised 735 control and 735 hypertensive subjects (mean age 59.3 ± 9.0 years), matched for age and sex. The CAD study, hospital-based subjects (mean age 62.1 ± 9.5 years), included 279 CAD patients and 165 non-CAD subjects. Gene polymorphisms were identified in genomic DNA using polymerase chain reaction (PCR)-based technique. Genetic variations were assessed for their associations with HT and severity of CAD. Antioxidant gene variants, SOD3 rs2536512-GG, GPX3 rs3828599-GG, PON1 rs705379-TT, and GSTT1^{-/- and +/-}, were independently associated with the incidence of HT. A combination of four HT-associated genotypes, as a genetic risk score (GRS), revealed an association of GRS 5 and GRS ≥ 6 with increased susceptibility to HT and CAD, and further with multivessel coronary atherosclerosis (multivessel CAD) compared with GRS 0-2 [respective ORs(95% CI) for GRS ≥ 6 = 2.37 (1.46-3.85), 3.26 (1.29-8.25), and 4.36 (1.36-14.0)]. Combined polymorphisms in these four antioxidant-related genes were associated with the incidences of HT and CAD, and with the severity of coronary atherosclerosis.

Genetic polymorphisms associated with reactive oxygen species and blood pressure regulation

Hypertension is the most prevalent cause of cardiovascular disease and kidney failure, but only about 50% of patients achieve adequate blood pressure control, in part, due to inter-individual genetic variations in the response to antihypertensive medication. Significant strides have been made toward the understanding of the role of reactive oxygen species (ROS) in the regulation of the cardiovascular system. However, the role of ROS in human hypertension is still unclear. Polymorphisms of some genes involved in the regulation of ROS production are associated with hypertension, suggesting their potential influence on blood pressure control and response to antihypertensive medication. This review provides an update on the genes associated with the regulation of ROS production in hypertension and discusses the controversies on the use of antioxidants in the treatment of hypertension, including the antioxidant effects of antihypertensive drugs.

Comparison of CAT-21A/T Gene Polymorphism in Women with Preeclampsia and Control Group

Background:

Preeclampsia (PE) is one of the main causes of maternal and perinatal mortality and morbidity. Evidence shows that oxidative stress plays an important role in the pathophysiology of the PE. As catalase is a key enzyme in antioxidant enzymatic defense which protects cell from oxidative damage, in this study, we aimed to investigate the relationship between CAT-21A/T (rs7943316) polymorphism and PE susceptibility.

Materials and Methods:

This case–control study was conducted on 155 PE women and 159 normotensive pregnant women. Polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping.

Results:

There was no association between CAT-21AT and TT genotypes and PE susceptibility. However, the CAT-21A/T polymorphism was associated with 1.6-fold higher risk of PE in dominant model (AA vs. AT + TT) (odds ratio [OR] 1.6 [95% confidence interval [CI]: 0.9–2.9]; P = 0.04). However, the CAT-21A/T polymorphism was not associated with PE in recessive model (TT vs. AA + AT) (OR 1.3 [95% CI: 0.8–2.1]; P = 0.4).

Conclusions:

The CAT-21A/T polymorphism could be a risk factor for PE susceptibility in dominant model.

The role of the thioredoxin/thioredoxin reductase system in the metabolic syndrome: towards a possible prognostic marker?

Mammalian thioredoxin reductase (TrxR) is a selenoprotein with three existing isoenzymes (TrxR1, TrxR2, and TrxR3), which is found primarily intracellularly but also in extracellular fluids. The main substrate thioredoxin (Trx) is similarly found (as Trx1 and Trx2) in various intracellular compartments, in blood plasma, and is the cell's major disulfide reductase. Thioredoxin reductase is necessary as a NADPH-dependent reducing agent in biochemical reactions involving Trx. Genetic and environmental factors like selenium status influence the activity of TrxR. Research shows that the Trx/TrxR system plays a significant role in the physiology of the adipose tissue, in carbohydrate metabolism, insulin production and sensitivity, blood pressure regulation, inflammation, chemotactic activity of macrophages, and atherogenesis. Based on recent research, it has been reported that the modulation of the Trx/TrxR system may be considered as a new target in the management of the metabolic syndrome, insulin resistance, and type 2 diabetes, as well as in the treatment of hypertension and atherosclerosis. In this review evidence about a possible role of this system as a marker of the metabolic syndrome is reported.

Gamma-glutamyltransferase, fatty liver index and hepatic insulin resistance are associated with incident hypertension in two longitudinal studies

OBJECTIVE

We hypothesized that liver markers and the fatty liver index (FLI) are predictive of incident hypertension and that hepatic insulin resistance plays a role.

METHODS

The association between liver markers and incident hypertension was analysed in two longitudinal studies of normotensive individuals, 2565 from the 9-year data from an epidemiological study on the insulin resistance cohort and the 321 from the 3-year 'Relationship between Insulin Sensitivity and Cardiovascular disease' cohort who had a measure of endogenous glucose production. The FLI is calculated from BMI, waist circumference, triglycerides and gamma-glutamyltransferase (GGT) and the hepatic insulin resistance index from endogenous glucose production and fasting insulin.

RESULTS

The incidence of hypertension increased across the quartiles groups of both baseline GGT and alanine aminotransferase. After adjustment for sex, age, waist circumference, fasting glucose, smoking and alcohol intake, only GGT was significantly related with incident hypertension [standardized odds ratio: 1.21; 95% confidence interval (1.10-1.34); P = 0.0001]. The change in GGT levels over the follow-up was also related with an increased risk of hypertension, independently of changes in body weight. FLI analysed as a continuous value, or FLI at least 60 at baseline were predictive of incident hypertension in the multivariable model. In the RISC cohort, the hepatic insulin resistance index was positively related with the risk of 3-year incident hypertension [standardized odds ratio: 1.54 (1.07-2.22); P = 0.02].

CONCLUSION

Baseline GGT and FLI, as well as an increase in GGT over time, were associated with the risk of incident hypertension. Enhanced hepatic insulin resistance predicted the onset of hypertension and may be a link between liver markers and hypertension.

Shared metabolic and immune-inflammatory, oxidative and nitrosative stress pathways in the metabolic syndrome and mood disorders

This review examines the shared immune-inflammatory, oxidative and nitrosative stress (IO&NS) and metabolic pathways underpinning metabolic syndrome (MetS), bipolar disorder (BD) and major depressive disorder (MDD). Shared pathways in both MetS and mood disorders are low grade inflammation, including increased levels of pro-inflammatory cytokines and acute phase proteins, increased lipid peroxidation with formation of malondialdehyde and oxidized low density lipoprotein cholesterol (LDL-c), hypernitrosylation, lowered levels of antioxidants, most importantly zinc and paraoxonase (PON1), increased bacterial translocation (leaky gut), increased atherogenic index of plasma and Castelli risk indices; and reduced levels of high-density lipoprotein (HDL-c) cholesterol. Insulin resistance is probably not a major factor associated with mood disorders. Given the high levels of IO&NS and metabolic dysregulation in BD and MDD and the high comorbidity with the atherogenic components of the MetS, mood disorders should be viewed as systemic neuro-IO&NS-metabolic disorders. The IO&NS-metabolic biomarkers may have prognostic value and may contribute to the development of novel treatments targeting neuro-immune, neuro-oxidative and neuro-nitrosative pathways.

Association of GCLM -588C/T and GCLC -129T/C Promoter Polymorphisms of Genes Coding the Subunits of Glutamate Cysteine Ligase with Ischemic Heart Disease Development in Kazakhstan Population

BACKGROUND

Glutamate cysteine ligase (GCL) is a rate-limiting enzyme in synthesis of glutathione. Evidence suggests that genetic variations in the promoter region of genes coding a catalytic subunit (GCLC -129T/C) and a modifier subunit (GCLM -588C/T) of GCL have a functional impact on their transcriptional activity and were associated with various disorders. Hence, we hypothesize whether these two polymorphic variants of GCLM and GCLC genes are associated with the risk of ischemic heart disease (IHD) development in the population of Kazakhstan.

METHODS

We evaluated 360 patients with IHD and 341 control subjects. Allele frequencies of studied promoters' polymorphisms were detected by PCR-RFLP analysis. Multiple logistic regression analysis was applied to assess the risk for different genotypes obtained.

RESULTS

The presence of -588T allele in GCLM and -129T allele in GCLC gene genotypes was associated with an increased risk of IHD (GCLM -588T: OR = 3.92, p = 0.003; GCLC -129T: OR = 3.22, p = 0.03) for general ethnically mixed group. Analysis of each ethnical groups separately showed the higher risk tendency for Kazakhs as for GCLM -588T (OR = 4.79; p = 0.03) and as for GCLC -129T (OR = 4.79, p = 0.03). For Russians, statistically differences for two polymorphisms were not observed.

CONCLUSION

The two promoter polymorphisms of GCLM (-588C/T) and GCLC (-128T/C) are associated with an increased risk of IHD in Kazakhstan population.

The nutrigenetic influence of the interaction between dietary vitamin E and TXN and COMT gene polymorphisms on waist circumference: a case control study

Background

Abdominal obesity (AO) is a common modifiable risk factor for certain non-communicable diseases associated with enhanced oxidative stress (OS). The objective of this work was to investigate whether the interaction between antioxidant vitamin intake and OS-related polymorphisms modulates gene-associated anthropometry in a Spanish population.

Methods

A total of 246 subjects with AO, and 492 age and gender matched non-AO subjects were included in the study. Anthropometric, biochemical, and OS parameters, and antioxidant dietary intake data were assessed using validated procedures. DNA from white blood cells was isolated and the genotype of seven polymorphisms from genes involved in OS (pro-oxidant and antioxidant) were analyzed using the SNPlex system. The effects of the c.-793T > C polymorphism on promoter activity and thus thioredoxin (TXN) activity were examined using reporter assays.

Results

The AO group had higher 8-Oxo-2′-deoxyguanosine levels and took in less vitamin A and vitamin E compared to the non-AO group. Logistic regression analysis revealed that the rs2301241 polymorphism in TXN and rs740603 in catechol-O-methyltransferase (COMT) were associated with waist circumference (WC) and AO. Moreover, these polymorphisms were more strongly associated with variations in WC in subjects with low vitamin E intakes. A promoter assay revealed that the T to C conversion at c.-793 (rs2301241) induced a more than two fold increase in reporter gene expression.

Conclusions

WC is associated both with dietary vitamin E intake and genetic variants of TXN and COMT suggesting that existence of a complex nutrigenetic pathway that involves regulation of AO.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0652-4) contains supplementary material, which is available to authorized users.

Metabolic syndrome, aging and involvement of oxidative stress

The prevalence of the metabolic syndrome, a cluster of cardiovascular risk factors associated with obesity and insulin resistance, is dramatically increasing in Western and developing countries. This disorder consists of a cluster of metabolic conditions, such as hypertriglyceridemia, hyper-low-density lipoproteins, hypo-high-density lipoproteins, insulin resistance, abnormal glucose tolerance and hypertension, that-in combination with genetic susceptibility and abdominal obesity-are risk factors for type 2 diabetes, vascular inflammation, atherosclerosis, and renal, liver and heart diseases. One of the defects in metabolic syndrome and its associated diseases is excess of reactive oxygen species. Reactive oxygen species generated by mitochondria, or from other sites within or outside the cell, cause damage to mitochondrial components and initiate degradative processes. Such toxic reactions contribute significantly to the aging process. In this article we review current understandings of oxidative stress in metabolic syndrome related disease and its possible contribution to accelerated senescence.

Environmental lead exposure, catalase gene, and markers of antioxidant and oxidative stress relation to hypertension: an analysis based on the EGAT study

Lead has been linked to the development of hypertension via oxidative stress. Catalase plays an important role in the disposal of hydrogen peroxide in erythrocyte and its activity was determined by CAT gene. The aims of this study were to investigate (1) the association between blood levels of antioxidant markers such as catalase, superoxide dismutase, glutathione, glutathione peroxidase, oxidative stress-marker (malondialdehyde), and blood lead level and (2) the influence of genetic polymorphism of CAT gene (rs769217) on change in blood pressure in general population of EGAT study project. This is a cross-sectional study of 332 normotensive, 432 prehypertensive, and 222 hypertensive male subjects. Hypertensive subjects had significantly higher blood lead level (5.28 μg/dL) compared to normotensive (4.41 μg/dL) and prehypertensive (4.55 μg/dL) subjects (P < 0.05). These significant findings are also found in MDA levels. Moreover, individuals with TT genotype in hypertensive group had significantly higher blood lead and MDA levels (6.06 μg/dL and 9.67 μmol/L) than those with CC genotype (5.32 μg/dL and 8.31 μmol/L, P < 0.05). Our findings suggested that decreased blood catalase activity in this polymorphism together with low level lead exposure induced lipid peroxidation may be responsible for hypertension.

rs2070424 of the SOD1 gene is associated with risk of Alzheimer's disease

OBJECTIVE

Oxidative stress plays an important role in Alzheimer's disease (AD) etiopathogenesis. There were several studies that showed impaired antioxidant defense system (ADS) enzymes expression or activity in AD patients. There are only few studies evaluating the importance of ADS gene single nucleotide polymorphisms (SNPs) as risk factors of AD. We evaluated association between chosen SNPs of the enzymes of the ADS and risk of AD.

METHODS

We included 400 AD patients and 402 healthy controls. We studied rs1041740, rs4998557 and rs2070424 of the SOD1 gene, rs2855116, rs5746136 and rs4880 of the SOD2 gene and rs3448, rs1050450 and rs1800668 of the GPx-1 gene (real time PCR). To determine the APOE gene common polymorphism, two single-nucleotide polymorphisms (SNPs; NCBI SNPs rs429358 and rs7412) were genotyped (TaqMan assays, Applied Biosystems [ABI], Foster City, CA, USA). The genotype and gender frequencies were compared between the studied groups by the χ(2) test and mean age by the t-Student test.

RESULTS

Among all studied SNPs only rs2070424 of the SOD1 gene was a protective factor for AD in an additive (OR=0.47; 95% CI=0.30-0.74, p=0.001) and recessive (OR=0.47; 95% CI=0.30-0.75, p=0.002) models including age, gender and APOE gene status.

CONCLUSIONS

rs2070424 polymorphism of the SOD1 gene is a risk factor for AD in Polish population. Allel G and genotype AG and GG are protective factors for AD.

A possible protective role of Nrf2 in preeclampsia

Excess release of reactive oxygen species (ROS) is a major cause of oxidative stress. This disturbance has been implicated as a cause of preeclampsia, a pregnancy-related disorder characterized by hypertension and proteinuria. Increased oxidative stress leads to trophoblast apoptosis/necrosis and alters the balance between pro- and anti-angiogenic factors, resulting in generalized maternal endothelial dysfunction. Trials using antioxidants have significantly failed to improve the condition of, or in any way protect, the mother from the life-threatening complications of this syndrome. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a potent transcription activator that regulates the expression of a multitude of genes that encode detoxification enzymes and anti-oxidative proteins. Recent discussion on evidence of a link between Nrf2 and vascular angiogenic balance has focussed on the downstream target protein, heme oxygenase-1 (HO-1). HO-1 metabolizes heme to biliverdin, iron and carbon monoxide (CO). HO-1/CO protects against hypertensive cardiovascular disease and contributes to the sustained health of the vascular system. In one animal model, sFlt-1 (soluble fms-like tyrosine kinase-1) has induced blood pressure elevation, but the induction of HO-1 attenuated the hypertensive response in the pregnant animals. The special conditions under which Nrf2 participates in the pathogenesis of preeclampsia are still unclear, as is whether Nrf2 attenuates or stimulates the processes involved in this syndrome. In this review, we summarize recent theories about how Nrf2 is involved in the pathogenesis of preeclampsia and present the reasons for considering Nrf2 as a therapeutic target for the treatment of preeclampsia.

SOD3 and eNOS genotypes are associated with SOD activity and NOx

Oxidative stress, characterized by increased reactive oxygen species production and/or decreased antioxidant enzyme activity, plays an important role in the pathogenesis of hypertension. The identification of molecular markers corresponding to the oxidative stress status of hypertension may assist in the antioxidant therapy of hypertension. In the present study, superoxide dismutase (SOD) and endothelial nitric oxide synthase (eNOS) were analyzed as markers of hypertension responding to oxidative stress. The plasma SOD activity and mononitrogen oxides (NO_x) concentration were measured, and the SOD3 Ala58Thr and eNOS Glu298Asp polymorphisms were genotyped in hypertensive patients and normotensive controls. Further association experiments were replicated in an extended population, including 343 hypertensive patients and 290 controls. The results demonstrated that no statistically significant differences in the total SOD activity and NO_x concentration were identified between the hypertensive patients and controls. However, the plasma SOD activity levels in the SOD3 Ala/Ala homozygote carriers (80.51±27.68 U/ml) were significantly lower compared with the Thr allele carriers (92.18±16.37 U/ml; P=0.031). In addition, the plasma NO_x concentration in the eNOS Glu/Glu homozygote carriers (129.66±59.15 μmol/l) was significantly lower compared with the Asp allele carriers (169.84± 55.18 μmol/l; P=0.010). Notably, the altered SOD activity levels and NO_x concentration were in concordance in 56.3% of the 80 participants. Therefore, the concordance of decreased SOD activity and NO_x concentration, combined with genotypes of SOD3 Ala/Ala and/or eNOS Glu/Glu in hypertensive patients, may be useful in directing the antioxidant therapy of hypertension.

The role of nutrition and nutraceutical supplements in the treatment of hypertension

Vascular biology, endothelial and vascular smooth muscle and cardiac dysfunction play a primary role in the initiation and perpetuation of hypertension, cardiovascular disease and target organ damage. Nutrient-gene interactions and epigenetics are predominant factors in promoting beneficial or detrimental effects in cardiovascular health and hypertension. Macronutrients and micronutrients can prevent, control and treat hypertension through numerous mechanisms related to vascular biology. Oxidative stress, inflammation and autoimmune dysfunction initiate and propagate hypertension and cardiovascular disease. There is a role for the selected use of single and component nutraceutical supplements, vitamins, antioxidants and minerals in the treatment of hypertension based on scientifically controlled studies which complement optimal nutrition, coupled with other lifestyle modifications.

Nutrition and nutraceutical supplements for the treatment of hypertension: part I

Vascular biology, endothelial and vascular smooth muscle, and cardiac dysfunction play a primary role in the initiation and perpetuation of hypertension, cardiovascular disease, and target organ damage. Nutrient-gene interactions and epigenetics are predominant factors in promoting beneficial or detrimental effects in cardiovascular health and hypertension. Macronutrients and micronutrients may be able to prevent, control, or treat hypertension through numerous mechanisms related to vascular biology or other mechanisms. Oxidative stress, inflammation, and autoimmune dysfunction are some of the primary factors that initiate and propagate hypertension and cardiovascular disease. The literature suggests that there may be a complementary role of single and component nutraceutical supplements, vitamins, antioxidants, and minerals in the treatment of hypertension when combined with optimal nutrition and other lifestyle modifications. However, many of these studies are small and do not have long-term follow-up for efficacy and safety. The role of these nutrition and nutraceutical supplements will require careful review and additional studies to determine their exact role in the management of hypertension.

The mosaic theory revisited: common molecular mechanisms coordinating diverse organ and cellular events in hypertension

More than 60 years ago, Dr. Irvine Page proposed the Mosaic Theory of hypertension, which states that many factors, including genetics, environment, adaptive, neural, mechanical, and hormonal perturbations interdigitate to raise blood pressure. In the past two decades, it has become clear that common molecular and cellular events in various organs underlie many features of the Mosaic Theory. Two of these are the production of reactive oxygen species and inflammation. These factors increase neuronal firing in specific brain centers, increase sympathetic outflow, alter vascular tone and morphology, and promote sodium retention in the kidney. Moreover, factors such as genetics and environment contribute to oxidant generation and inflammation. Other common cellular signals, including calcium signaling and endoplasmic reticulum stress are similarly perturbed in different cells in hypertension and contribute to components of Page's theory. Thus, Page's Mosaic Theory formed a framework for future studies of molecular and cellular signals in the context of hypertension, and has greatly aided our understanding of this complex disease.

Loss of oxidative stress tolerance in hypertension is linked to reduced catalase activity and increased c-Jun NH2-terminal kinase activation

Hypertension is accompanied by increased levels of reactive oxygen species, which may contribute to progressive renal injury and dysfunction. Here we tested the hypothesis that sensitivity to exogenous hydrogen peroxide (H(2)O(2)) is enhanced in immortalized renal proximal tubular epithelial cells from spontaneously hypertensive rats (SHR) compared to normotensive control Wistar Kyoto rats (WKY). We found that SHR cells were more sensitive to H(2)O(2)-induced cell death than WKY cells. Lower survival in SHR cells correlated with increased DNA fragmentation, chromatin condensation, and caspase-3 activity, indicating apoptosis. H(2)O(2) degradation was slower in SHR than in WKY cells, suggesting that reduced antioxidant enzyme activity might be the basis for their increased sensitivity. In fact, catalase activity was downregulated in SHR cells, whereas glutathione peroxidase activity was similar in both cell types. We next examined whether MAPK signaling pathways contributed to H(2)O(2)-mediated apoptosis. Inhibition of c-Jun NH(2)-terminal kinase (JNK) with SP600125 partially rescued H(2)O(2)-induced apoptosis in WKY but not in SHR cells. In addition, p54 JNK2 isoform was robustly phosphorylated by H(2)O(2), this effect being more pronounced in SHR cells. Together, these results suggest that the survival disadvantage of SHR cells upon exposure to H(2)O(2) stems from impaired antioxidant mechanisms and activated JNK proapoptotic signaling pathways.

Systematic testing of literature reported genetic variation associated with coronary restenosis: results of the GENDER Study

Background

Coronary restenosis after percutaneous coronary intervention still remains a significant problem, despite all medical advances. Unraveling the mechanisms leading to restenosis development remains challenging. Many studies have identified genetic markers associated with restenosis, but consistent replication of the reported markers is scarce. The aim of the current study was to analyze the joined effect of previously in literature reported candidate genes for restenosis in the GENetic DEterminants of Restenosis (GENDER) databank.

Methodology/Principal Findings

Candidate genes were selected using a MEDLINE search including the terms ‘genetic polymorphism’ and ‘coronary restenosis’. The final set included 36 genes. Subsequently, all single nucleotide polymorphisms (SNPs) in the genomic region of these genes were analyzed in GENDER using set-based analysis in PLINK. The GENDER databank contains genotypic data of 2,571,586 SNPs of 295 cases with restenosis and 571 matched controls. The set, including all 36 literature reported genes, was, indeed, significantly associated with restenosis, p = 0.024 in the GENDER study. Subsequent analyses of the individual genes demonstrated that the observed association of the complete set was determined by 6 of the 36 genes.

Conclusion

Despite overt inconsistencies in literature, with regard to individual candidate gene studies, this is the first study demonstrating that the joint effect of all these genes together, indeed, is associated with restenosis.

Catalase polymorphisms and metabolic diseases

PURPOSE OF REVIEW

This review summarizes our current understanding of the implication of catalase polymorphisms in the occurrence, control and comorbidities of metabolic diseases.

RECENT FINDINGS

Whatever impaired glucose tolerance, insulin resistance on diabetes and whatever their occurrence or implications, the studies taken together converge toward the hypothesis that catalase polymorphisms play a role in glucose disorders. -262C/T and -844A>G single nucleotide polymorphisms are associated to hypertension susceptibility and/or onset. Concerning dyslipidemia, very recent studies requiring confirmation report a -262C/T implication. Finally, a role of catalase polymorphisms in bone metabolism is described.

SUMMARY

Plethora of studies on catalase SNPs and their link with diseases exist. It is now clear that genetic variations in the catalase gene and its promoter are putative risk factors for metabolic disease. The question of how these polymorphisms actively play a role in various metabolisms remains unanswered. Further functional studies are required in order to gain a deeper insight into the direct role of catalase.

Effect of felodipine with irbesartan or metoprolol on sexual function and oxidative stress in women with essential hypertension

OBJECTIVE

To evaluate the impact of felodipine with irbesartan on sexual function compared with felodipine with metoprolol in hypertensive women.

METHODS

This was a prospective, randomized, parallel, active-controlled, open-label study (ClinicalTrials.org: NCT01238705) in 160 women (18-60 years) with mild or moderate hypertension, randomized to a once-daily treatment with felodipine combined with irbesartan or metoprolol for 48 weeks. Patients' sexual function was evaluated using a female sexual function index (FSFI) questionnaire at baseline and after 24 and 48 weeks of therapy. Levels of serum estradiol, testosterone, 8-hydroxy-2'-deoxyguanosine (8-OHdG), 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) were measured.

RESULTS

The two combination regimens were similarly effective in lowering blood pressure. After 48 weeks, in felodipine-irbesartan group, total scores of FSFI improved (P < 0.001). Items showing improvement in scores corresponded to desire, arousal and orgasm (P < 0.001; P = 0.002; P = 0.049, respectively). Levels of estradiol increased under treatment with felodipine-irbesartan (P = 0.003) and decreased under felodipine-metoprolol treatment (P < 0.001). The concentration of testosterone declined after felodipine-irbesartan therapy (P < 0.001) and increased under felodipine-metoprolol treatment (P < 0.001). In the felodipine-irbesartan group, decreases of 8-OHdG, 4-HNE (P < 0.001) and MDA (P < 0.001) were observed. The felodipine-irbesartan combination resulted in less oxidative stress. The differences in changes in 8-OHdG, 4-HNE and MDA between the two groups were significant (P < 0.05).

CONCLUSION

These results suggested that the felodipine-irbesartan combination regimen improved sexual function in hypertensive women, whereas felodipine-metoprolol regiment did not. The reason for the different influence of these two combination therapy on female sexual function might be their different impacts on oxidative stress and hormone levels.