Tetrahydrobiopterin: a vascular redox target to improve endothelial function

Loss of normal endothelial function and bioactivity of nitric oxide (NO), associated with increased production of reactive oxygen species (ROS), are characteristics of cardiovascular disease states. There is good experimental evidence that these abnormalities are causally related to cardiovascular disease pathogeneses, and are amenable to therapeutic intervention. However, simple attempts to increase NO levels or reduce "oxidative stress", for example using nonselective anti-oxidant drugs, have shown no benefit as treatments of cardiovascular disease. Increasing evidence highlights the need to better understand NO and ROS mediated signaling mechanisms in endothelial function, in order to identify more rational and selective therapeutic targets. The NO synthase co-factor, tetrahydrobiopterin (BH4) is a redox active molecule which regulates NO and ROS production by NO synthase and provides an exemplar of redox dependent signaling in the endothelium, with relevance to cardiovascular disease. Loss of endothelial cell BH4 is observed in cardiovascular disease states and results in loss of NO, but increased ROS production by endothelial NO synthase. Genetic mouse models of augmented endothelial cell BH4 synthesis have shown proof of concept that endothelial cell BH4 can alter cardiovascular disease pathogenesis, but clinical trials of BH4 therapy in vascular disease have been limited by systemic oxidation and limited endothelial cell uptake of BH4. In contrast, some existing therapies such as statins appear to exert favourable effects on endothelial cell BH4 and endothelial NO synthase function. Identifying specific redox mechanisms and targets in the endothelium will provide new potential targets for future drug treatments.

Novel therapeutic approaches in limiting oxidative stress and inflammation

The interaction between reactive oxygen species (ROS) and inflammation plays an important role in the pathogenesis of endothelial dysfunction and cardiovascular disease, cancer and other diseases. Thus, antioxidant strategies may be important in immune regulation and in limiting inflammation. Surprisingly, large clinical trials have shown that ROS scavenging by antioxidant vitamins is ineffective or even harmful in spite of the fact that reactive oxygen species themselves are pro-inflammatory, regulate immune system and enhance atherosclerosis. Therefore, there is a need of novel, more specific antioxidant and anti-inflammatory approaches aimed on prevention of ROS formation, by targeting specific molecular pathways involved in ROS generation and their activation of pro-inflammatory cascades. Potential targets include the NADPH oxidases (Nox enzymes), xanthine oxidase, endothelial nitric oxide synthase and mitochondrial oxidases. Nox enzymes play central role, as they can stimulate other enzymatic sources of ROS. The interplay between inflammation and oxidative stress is discussed in the context of adipose tissue, perivascular inflammation and role of the central nervous system in immune regulation. All of the above participate in "brain-vessel axis" critical in the pathogenesis of numerous pathologies. Role of cytokines such as TNF-alpha, IL-17 or IL-6 and their links to superoxide and hydrogen peroxide production are discussed. Statins, angiotensin converting enzyme inhibitors and angiotensin II receptor antagonists, block upstream signaling of Nox activation, including MAP kinase signaling or G protein activation, which contribute to their clinical effectiveness. Here, we discuss novel possibilities that drugs directly inhibiting Nox activation could successfully inhibit oxidative stress and inflammation related to cardiovascular disease. Moreover, we describe potential gene therapy approaches in limiting oxidative stress in the vasculature. These approaches can become also useful in cancer immunomodulation.

Cardiac cyclic nucleotide phosphodiesterases: function, regulation, and therapeutic prospects

The second messengers cAMP and cGMP exist in multiple discrete compartments and regulate a variety of biological processes in the heart. The cyclic nucleotide phosphodiesterases, by catalyzing the hydrolysis of cAMP and cGMP, play crucial roles in controlling the amplitude, duration, and compartmentalization of cyclic nucleotide signaling. Over 60 phosphodiesterase isoforms, grouped into 11 families, have been discovered to date. In the heart, both cAMP- and cGMP-hydrolyzing phosphodiesterases play important roles in physiology and pathology. At least 7 of the 11 phosphodiesterase family members appear to be expressed in the myocardium, and evidence supports phosphodiesterase involvement in regulation of many processes important for normal cardiac function including pacemaking and contractility, as well as many pathological processes including remodeling and myocyte apoptosis. Pharmacological inhibitors for a number of phosphodiesterase families have also been used clinically or preclinically to treat several types of cardiovascular disease. In addition, phosphodiesterase inhibitors are also being considered for treatment of many forms of disease outside the cardiovascular system, raising the possibility of cardiovascular side effects of such agents. This review will discuss the roles of phosphodiesterases in the heart, in terms of expression patterns, regulation, and involvement in physiological and pathological functions. Additionally, the cardiac effects of various phosphodiesterase inhibitors, both potentially beneficial and detrimental, will be discussed.

Extremes of an aromatase index predict increased 25-year risk of cardiovascular mortality in older women

BACKGROUND

Peripheral conversion of androgens to oestrogens via aromatase is the primary source of oestrogen in postmenopausal women and may play a role in cardiovascular health.

DESIGN

Prospective. PARTICIPANTS, MEASUREMENTS: The association of an index of aromatase activity (AROM), the serum oestrone-to-androstenedione ratio, with 25-year cardiovascular disease (CVD) mortality was examined in 819 postmenopausal non-oestrogen using women (mean age at baseline = 72).

RESULTS

Overall, 247 deaths were attributed to CVD. The median AROM value was 60 (95% range 17-129). AROM was positively correlated with age (r = 0·28) and body mass index (BMI) (r = 0·22) (P < 0·001). The age-adjusted risk for CVD mortality was significantly elevated for women in the lowest (HR = 2·01, 95% CI 1·31-3·12) and highest (HR = 1·51, 95%CI 1·02-2·22) quintiles of AROM, compared with the middle quintile. This U-shaped association persisted after additional adjustment for BMI, waist-to-hip ratio, exercise, smoking, alcohol use and traditional CVD risk factor covariates. There was a significant interaction of AROM and BMI (P = 0·001), such that high AROM was associated with a 63% reduction in risk of CVD death for women with low BMI (<22 kg/m(2) ), but with 2·1- to 2·5-fold increased risk in women with mid-range (22-<25 kg/m(2) ) and high (≥25 kg/m(2) ) BMI. Oestradiol did not influence AROM associations and was not independently related to CVD death.

CONCLUSIONS

These results suggest that aromatase is a novel endocrine factor predictive of CVD mortality among postmenopausal women. If confirmed, additional studies are needed to determine whether extremes of aromatase reflect genetic influences or underlying disease processes.

Aldose reductase, oxidative stress and diabetic cardiovascular complications

Cardiovascular disease represents the major cause of morbidity and mortality in patients with diabetes mellitus. Studies by us and others have implicated increased flux via aldose reductase (AR) as a key player in mediating diabetic complications, including cardiovascular complications. Data suggest that increased flux via AR in diabetics perpetuates increased injury after myocardial infarction, accelerates atherosclerotic lesion formation, and promotes restenosis via multiple mechanisms. Most importantly, studies have shown that increased generation of reactive oxygen species due to flux via AR has been a common feature in animal models of diabetic cardiovascular disease. Taken together, these considerations place AR in the center of biochemical and molecular stresses that characterize the cardiovascular complications of diabetes. Stopping AR-dependent signaling may hold the key to interrupting cycles of cellular perturbation and tissue damage in diabetic cardiovascular complications.

A randomized trial of copper supplementation effects on blood copper enzyme activities and parameters related to cardiovascular health

Marginal copper deficiency, which may affect cardiovascular disease risk, is proposed to occur in many adults in Western industrialized countries. The present study tested the hypothesis that in a group of USA adults, increased copper intake would alter readings for blood copper enzymes and markers relevant to cardiovascular disease risk. Healthy middle aged adults with moderately high cholesterol, were given either placebo or copper supplementation (2 mg copper/day as copper glycinate) for 8 weeks. Blood samples were taken before and after the 8 weeks. Copper, but not placebo, raised activities for two copper enzymes, erythrocyte superoxide dismutase 1 and plasma ceruloplasmin. In contrast, five cardiovascular health related plasma parameters were not changed significantly by copper: C-reactive protein, homocysteine, and cholesterol (total, LDL and HDL). However, changes in erythrocyte superoxide dismutase 1 correlated positively with changes in plasma HDL and negatively with plasma homocysteine. Also, copper lowered mean oxidized LDL values, a result that was statistically significant, but inconsistent. In this test population, increased copper intake raised copper enzyme activities, but did not consistently improve the cardiovascular health measures studied.

Predicting the Risk of Cardiovascular Disease

Although an atherogenic lipoprotein phenotype has been well recognized as an important predictor of cardiovascular disease, recent studies have demonstrated a number of additional lipid-related markers as emerging biomarkers to identify patients at risk for future coronary heart disease. Among them, lipoprotein-associated phospholipase A(2) (Lp-PLA(2)), seems to be a promising candidate that might be added to the clinical armamentarium for improved prediction of cardiovascular disease in the future. Of particular note, Lp-PLA(2) is the only enzyme that cleaves oxidized low-density lipoprotein (oxLDL) in the subendothelial space, with further generation of proinflammatory mediators such as lysophosphatidylcholine (LysoPC) and oxidized fatty acid (oxFA), thereby probably linking two important features of atherogenesis, namely oxidation of LDL and local inflammatory processes within the atherosclerotic plaque. This overview aims to summarize our current knowledge based on observations from recent experimental and clinical studies. Emphasis has been put on potential pathophysiological mechanisms of action and on the clinical relevance of Lp-PLA(2) in a wide variety of clinical settings, including apparently healthy individuals, patients with stable angina or acute coronary syndromes, after myocardial infarction, and with subclinical disease. Although a growing body of evidence from epidemiological and clinical studies suggests that Lp-PLA(2) may represent an independent and clinically relevant long-term risk marker for coronary heart disease and, probably, also for stroke, the role of this enzyme in the setting of the acute coronary syndrome remains to be established.

DNA methylation analysis of the angiotensin converting enzyme (ACE) gene in major depression

BACKGROUND

The angiotensin converting enzyme (ACE) has been repeatedly discussed as susceptibility factor for major depression (MD) and the bi-directional relation between MD and cardiovascular disorders (CVD). In this context, functional polymorphisms of the ACE gene have been linked to depression, to antidepressant treatment response, to ACE serum concentrations, as well as to hypertension, myocardial infarction and CVD risk markers. The mostly investigated ACE Ins/Del polymorphism accounts for ~40%-50% of the ACE serum concentration variance, the remaining half is probably determined by other genetic, environmental or epigenetic factors, but these are poorly understood.

MATERIALS AND METHODS

The main aim of the present study was the analysis of the DNA methylation pattern in the regulatory region of the ACE gene in peripheral leukocytes of 81 MD patients and 81 healthy controls.

RESULTS

We detected intensive DNA methylation within a recently described, functional important region of the ACE gene promoter including hypermethylation in depressed patients (p = 0.008) and a significant inverse correlation between the ACE serum concentration and ACE promoter methylation frequency in the total sample (p = 0.02). Furthermore, a significant inverse correlation between the concentrations of the inflammatory CVD risk markers ICAM-1, E-selectin and P-selectin and the degree of ACE promoter methylation in MD patients could be demonstrated (p = 0.01 - 0.04).

CONCLUSION

The results of the present study suggest that aberrations in ACE promoter DNA methylation may be an underlying cause of MD and probably a common pathogenic factor for the bi-directional relationship between MD and cardiovascular disorders.

Effect of chronic forced running on gene expression of catecholamine biosynthetic enzymes in stellate ganglia of rats

The sympathoneural system has a profound influence on the heart function. Sympathetic neurons are the major contributors to the huge rise of circulating noradrenaline (NA) level in response to stressful stimuli. Treadmill training in rats is forced exercise which has the propensity to induce both psychological and physical stress. The aim of this study is to examine how chronic forced running (CFR) affects the expression of catecholamine biosynthetic enzymes (tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT)) and cAMP response element-binding (CREB) in stellate ganglia, as well as the concentrations of catecholamines, adrenocorticotropic hormone (ACTH) and corticosterone (CORT) in the plasma of rats. Also, we investigated how the additional acute immobilization stress changes the mentioned parameters. The rat training program consisted of 12 weeks running on a treadmill (20 m/min, 20 min/day). We found that CFR increases TH and DBH mRNA and protein levels in stellate ganglia, which is followed by increased NA concentration in the plasma. CFR reduces the level of PNMT mRNA, while the level of PNMT protein remains unchanged in stellate ganglia. The increased expression of TH and DBH genes positively correlates with the expression of CREB in stellate ganglia and with plasma ACTH level, while reduced level of PNMT mRNA in stellate ganglia correlates with reduced plasma CORT level. The additional acute immobilization stress increased gene expression of catecholamine biosynthetic enzymes in stellate ganglia, as well as catecholamines, ACTH and CORT levels in the plasma. The results presented here suggest that the continuous increase of the noradrenaline biosynthetic enzyme expression in stellate ganglia due to CFR may play a role in growing risk of cardiovascular diseases.

Variation of lipoprotein associated phospholipase A2 across demographic characteristics and cardiovascular risk factors: a systematic review of the literature

BACKGROUND

Lipoprotein association phospholipase A2 (Lp-PLA(2)), an enzyme which has been found in atherosclerotic plaque is currently under investigation in large Phase III clinical trials of vascular disease prevention. We assessed in a variety of different population settings variation of Lp-PLA(2) mass and activity across gender, ethnicity, diabetes, kidney disease and metabolic syndrome. We also assessed correlations with measures of circulating lipids, systemic inflammation and adiposity.

METHODS

Systematic review of studies measuring Lp-PLA(2) and at least one of the relevant characteristics in >50 participants.

RESULTS

We identified a total of 77 studies involving 102,499 participants meeting the inclusion criteria. Lp-PLA(2) mass and activity were consistently approximately 10% higher in males than females and 15% higher in Caucasians than African Americans or Hispanics. There were no clear associations of Lp-PLA(2) mass or activity with type II diabetes, markers of systemic inflammation (C-reactive protein, fibrinogen) or with body mass index. Correlations of Lp-PLA(2) mass or activity with low density lipoprotein cholesterol and apolipoprotein B were moderate and positive, whilst correlations with high density lipoprotein cholesterol were negative and moderate to weak. There was no clear differences in associations with any of the above characteristics in groups defined based upon prevalent cardiovascular disease or its risk factors.

CONCLUSIONS

Despite considerable variability in absolute levels of Lp-PLA(2) across studies, the variability of Lp-PLA(2) across gender, ethnicity, and levels of circulating lipids and markers of systemic inflammation are more consistent and appear not to vary importantly across categories defined by CVD or its risk factors.

Atypical protein kinase C in cardiometabolic abnormalities

PURPOSE OF REVIEW

To review the aberrations of insulin signaling to atypical protein kinase C (aPKC) in muscle and liver that generate cardiovascular risk factors, including obesity, hypertriglyceridemia, hypercholesterolemia, insulin resistance and glucose intolerance in type 2 diabetes mellitus (T2DM), and obesity-associated metabolic syndrome (MetSyn).

RECENT FINDINGS

aPKC and Akt mediate the insulin effects on glucose transport in muscle and synthesis of lipids, cytokines and glucose in liver. In T2DM, whereas Akt and aPKC activation are diminished in muscle, and hepatic Akt activation is diminished, hepatic aPKC activation is conserved. Imbalance between muscle and hepatic aPKC activation (and expression of PKC-ι in humans) by insulin results from differential downregulation of insulin receptor substrates that control phosphatidylinositol-3-kinase. Conserved activation of hepatic aPKC in hyperinsulinemic states of T2DM, obesity and MetSyn is problematic, as excessive activation of aPKC-dependent lipogenic, gluconeogenic and proinflammatory pathways increases the cardiovascular risk factors. Indeed, selective inhibition of hepatic aPKC by adenoviral-mediated expression of kinase-inactive aPKC, or newly developed small-molecule biochemicals, dramatically improves abdominal obesity, hepatosteatosis, hypertriglyceridemia, hypercholesterolemia, insulin resistance and glucose intolerance in murine models of obesity and T2DM.

SUMMARY

Hepatic aPKC is a unifying target for treating multiple clinical abnormalities that increase the cardiovascular risk in insulin-resistant states of obesity, MetSyn and T2DM.

Angiotensin-converting enzyme deletion allele is beneficial for the longevity of Europeans

The human angiotensin converting enzyme (ACE) gene is one of the most investigated candidate genes for cardiovascular diseases (CVD), but the understanding of its role among the elderly is vague. Therefore, this study focuses at: (a) testing the association of ACE polymorphism with CVD risk factors among the elderly, and (b) detecting the possible unequal distribution of ACE genotypes between senescent and younger segments of the European populations. The association of ACE I/D polymorphism with CVD health status [hypertension (HT), obesity, dislypidemia] in 301 very old subjects (88.2 ± 5 years; F/M = 221/80) was tested by means of logistic regression analysis. The meta-analysis of D allele frequency in general vs. elderly (80+ years) groups was conducted using all publicly available data for European populations comprising both age cohorts. Multiple multinomial logistic regression revealed that within this elderly sample, age (younger olds, 80-90 years), female sex (OR = 3.13, 95% CI = 1.59-6.19), and elevated triglycerides (OR = 2.53, 95% CI = 1.29-4.95) were positively associated with HT, while ACE polymorphism was not. It was also established that the DD genotype was twice as high in 80+ cohort compared to general population of Croatia (p < 0.00001). This trend was confirmed by the meta-analysis that showed higher D allele frequencies in olds from nine of ten considered European populations (OR = 1.19, 95% CI = 1.08-1.31). The data in elderly cohort do not confirm previously reported role of ACE DD genotype to the development of HT. Moreover, meta-analysis indicated that ACE D allele has some selective advantage that contributes to longevity in majority of European populations.

Phospholipase A(2) enzymes in metabolic and cardiovascular diseases

PURPOSE OF REVIEW

The phospholipase A2 (PLA2) family of proteins includes lipolytic enzymes that liberate the sn-2 fatty acyl chains from phospholipids to yield nonesterified fatty acids and lysophospholipids. The purpose of this review is to discuss recent findings showing distinct roles of several of these PLA2 enzymes in inflammatory metabolic diseases such as diabetes and atherosclerosis.

RECENT FINDINGS

The group 1B PLA2 digestion of phospholipids in the intestinal lumen facilitates postprandial lysophospholipid absorption, which suppresses hepatic fatty acid oxidation leading to increased VLDL synthesis, decreased glucose tolerance, and promotion of tissue lipid deposition to accentuate diet-induced hyperlipidemia, diabetes, and obesity. Other secretory PLA2s promote inflammatory metabolic diseases by generating bioactive lipid metabolites to induce inflammatory cytokine production, whereas the major intracellular PLA2s, cPLA2α, and iPLA2, generate arachidonic acid and lysophosphatic acid in response to extracellular stimuli to activate leukocyte chemotactic response.

SUMMARY

Each member of the PLA2 family of enzymes serves a distinct role in generating active lipid metabolites that promote inflammatory metabolic diseases including atherosclerosis, hyperlipidemia, obesity, and diabetes. The development of specific drugs that target one or more of these PLA2 enzymes may be novel strategies for treatment of these chronic inflammatory metabolic disorders.

Phenotyping vs. genotyping for prediction of clopidogrel efficacy and safety: the PEGASUS-PCI study

BACKGROUND

Prognostic values of genotyping and phenotyping for assessment of clopidogrel responsiveness have been shown in independent studies.

OBJECTIVES

To compare different assays for prediction of events during long-term follow-up.

METHODS

In this prospective cohort study polymorphisms of CYP2C19*2 and CYP2C19*17 alleles, vasodilator-stimulated phosphoprotein phosphorylation (VASP) assay, multiple electrode aggregometry (MEA), cone and platelet analyser (CPA) and platelet function analyser (PFA-100) were performed in 416 patients undergoing percutaneous coronary intervention. The rates of events were recorded during a 12-month follow-up.

RESULTS

Platelet aggregation by MEA predicted stent thrombosis (2.4%) better (c-index = 0.90; P < 0.001; sensitivity = 90%; specificity = 83%) than the VASP assay, CPA or PFA-100 (c-index < 0.70; P > 0.05; sensitivity < 70%; specificity < 70% for all) or even the CYP2C19*2 polymorphism (c-index < 0.56; P > 0.05; sensitivity = 30%; specificity = 71%). Survival analysis indicated that patients classified as poor responders by MEA had a substantially higher risk of developing stent thrombosis or MACE than clopidogrel responders (12.5% vs. 0.3%, P < 0.001, and 18.5% vs. 11.3%, P = 0.022, respectively), whereas poor metabolizers (CYP2C19*1/*2 or *2/*2 carriers) were not at increased risks (stent thrombosis, 2.7% vs. 2.5%, P > 0.05; MACE, 13.5% vs. 12.1%, P = 0.556). The incidence of major bleedings (2.6%) was numerically higher in patients with an enhanced vs. poor response to clopidogrel assessed by MEA (4% vs. 0%) or in ultra-metabolizers vs. regular metabolizers (CYP2C19*17/*17 vs. CYP2C19*1/*1; 9.5% vs. 2%). The classification tree analysis demonstrated that acute coronary syndrome at hospitalization and diabetes mellitus were the best discriminators for clopidogrel responder status.

CONCLUSIONS

 Phenotyping of platelet response to clopidogrel was a better predictor of stent thrombosis than genotyping.

Nitric oxide synthases: regulation and function

Nitric oxide (NO), the smallest signalling molecule known, is produced by three isoforms of NO synthase (NOS; EC 1.14.13.39). They all utilize l-arginine and molecular oxygen as substrates and require the cofactors reduced nicotinamide-adenine-dinucleotide phosphate (NADPH), flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN), and (6R-)5,6,7,8-tetrahydrobiopterin (BH(4)). All NOS bind calmodulin and contain haem. Neuronal NOS (nNOS, NOS I) is constitutively expressed in central and peripheral neurons and some other cell types. Its functions include synaptic plasticity in the central nervous system (CNS), central regulation of blood pressure, smooth muscle relaxation, and vasodilatation via peripheral nitrergic nerves. Nitrergic nerves are of particular importance in the relaxation of corpus cavernosum and penile erection. Phosphodiesterase 5 inhibitors (sildenafil, vardenafil, and tadalafil) require at least a residual nNOS activity for their action. Inducible NOS (NOS II) can be expressed in many cell types in response to lipopolysaccharide, cytokines, or other agents. Inducible NOS generates large amounts of NO that have cytostatic effects on parasitic target cells. Inducible NOS contributes to the pathophysiology of inflammatory diseases and septic shock. Endothelial NOS (eNOS, NOS III) is mostly expressed in endothelial cells. It keeps blood vessels dilated, controls blood pressure, and has numerous other vasoprotective and anti-atherosclerotic effects. Many cardiovascular risk factors lead to oxidative stress, eNOS uncoupling, and endothelial dysfunction in the vasculature. Pharmacologically, vascular oxidative stress can be reduced and eNOS functionality restored with renin- and angiotensin-converting enzyme-inhibitors, with angiotensin receptor blockers, and with statins.

The Alu polymorphism of angiotensin I converting enzyme (ACE) and atherosclerosis, incident chronic diseases and mortality in an elderly Chinese population

OBJECTIVE

We examined the contribution of ACE I/D polymorphism in a large Chinese population to four year change in ankle-brachial index (ABI), development of cardiovascular diseases and mortality in a prospective study adjusting for many confounding factors.

METHOD

Data are drawn from a longitudinal study of 4000 community-living men and women aged 65 years and over, for which detailed information regarding lifestyle, chronic diseases, body mass index (BMI), ABI measurements and ACE polymorphisms were documented at baseline. During the fifth year of follow up, incident cardiovascular diseases, ABI, and mortality were documented, and related to ACE genotype adjusting for age, smoking, alcohol, dietary intake, physical activity, body mass index, and use of ACE inhibitors.

RESULTS

Women with the D/D genotype had the greatest reduction in mean ABI after adjusting for confounding factors. D/D genotype was also more common among women who developed hypertension or myocardial infarction. However D/D genotype was associated with mortality only in men.

CONCLUSION

In a Chinese elderly population, ACE polymorphism may be considered "deleterious" to longevity, the D/D genotype being associated with mortality, the atherosclerotic process, hypertension and myocardial infarction. There are gender differences in the relationship between D/D genotype and cardiovascular diseases and mortality may not be mediated by the atherosclerotic process alone.

Matrix metalloproteinases in metabolic syndrome

Metabolic syndrome is commonly accompanied by an elevated cardiovascular risk with high morbidity and mortality. The alterations of the arterial vasculature begin with endothelial dysfunction and lead to micro- and macrovascular complications. The remodeling of the endothelial basal membrane, that promotes erosion and thrombosis, has a multifactorial pathogenesis that includes leukocyte activation, increased oxidative stress and also an altered matrix metalloproteinases (MMPs) expression. MMPs are endopeptidases which degrade extracellular matrix proteins, such as collagen, gelatins, fibronectin and laminin. They can be secreted by several cells within the vascular wall, but macrophages are determinant in the atherosclerotic plaques. Their activity is regulated by tissue inhibitors of MMP (TIMPs) and also by other molecules, such as plasmin. MMPs could be implicated in plaque instability predisposing to vascular complications. It has been demonstrated that an impaired MMP or TIMP expression is associated with higher risk of all-cause mortality. A large number of studies evaluated MMPs pattern in obesity, diabetes mellitus, arterial hypertension and dyslipidemia, all of which define metabolic syndrome according to several Consensus Statement (i.e. IDF, ATP III, AHA). However, few research have been carried out on subjects with metabolic syndrome. The evidences of an improvement in MMP/TIMP ratio with diet, exercise and medical therapy should encourage further investigations with the intent to contrast the atherosclerotic process and to reduce morbidity and mortality of this kind of patients.

Alcohol consumption, genetic variants in alcohol deydrogenases, and risk of cardiovascular diseases: a prospective study and meta-analysis

Objective

First, to investigate and compare associations between alcohol consumption and variants in alcohol dehydrogenase (ADH) genes with incidence of cardiovascular diseases (CVD) in a large German cohort. Second, to quantitatively summarize available evidence of prospective studies on polymorphisms in ADH1B and ADH1C and CVD-risk.

Methods

We conducted a case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort including a randomly drawn subcohort (n = 2175) and incident cases of myocardial infarction (MI; n = 230) or stroke (n = 208). Mean follow-up time was 8.2±2.2 years. The association between alcohol consumption, ADH1B or ADH1C genotypes, and CVD-risk was assessed using Cox proportional hazards regression. Additionally, we report results on associations of variants in ADH1B and ADH1C with ischemic heart disease and stroke in the context of a meta-analysis of previously published prospective studies published up to November 2011.

Results

Compared to individuals who drank >0 to 6 g alcohol/d, we observed a reduced risk of MI among females consuming >12 g alcohol/d (HR = 0.31; 95% CI: 0.10–0.97) and among males consuming >24 to 60 g/d (HR = 0.57; 95% CI: 0.33–0.98) or >60 g alcohol/d (HR = 0.30; 95% CI: 0.12–0.78). Stroke risk was not significantly related to alcohol consumption >6 g/d, but we observed an increased risk of stroke in men reporting no alcohol consumption. Individuals with the slow-coding ADH1B*1/1 genotype reported higher median alcohol consumption. Yet, polymorphisms in ADH1B or ADH1C were not significantly associated with risk of CVD in our data and after pooling results of eligible prospective studies [ADH1B*1/1: RR = 1.35 (95% CI: 0.98–1.88; p for heterogeneity: 0.364); ADH1C*2/2: RR = 1.07 (95% CI: 0.90–1.27; p for heterogeneity: 0.098)].

Conclusion

The well described association between alcohol consumption and CVD-risk is not reflected by ADH polymorphisms, which modify the rate of ethanol oxidation.

[Na+, K(+)-ATPase, endogenous cardiotonic steroids and their transducing role]

Na+, K(+)-ATPase--a protein complex of plasmatic membrane, which performs the dual function: firstly, it supports the Na+ and K+ homeostasis, and also transmembrane potential gradient, secondly, it serves as the transducer of signals and as the regulator of the expression of many key genes. Endogenous cardiotonic steroids, which are synthesized in the adrenal glands and hypothalamus, serve as the signal molecules. New concepts about the mechanisms of the realization of the Na+, K(+)-ATPase signal function and their connection with cellular functions, apoptosis, and with pathologies of cardiovascular system and water-salt homeostasis are described in the survey.

Study of changes in antioxidant enzymes status in diabetic post menopausal group of women suffering from cardiovascular complications

BACKGROUND

In type 2 diabetic patients, persistence of hyperglycemia has been reported as a cause of increased production of oxygen free radicals (FR), which leads to oxidative stress (OS) and becomes the main factor for predisposition to the cardiovascular complications in diabetes. Diabetic postmenopausal women are prone to cardiovascular disease due to reduced production of estrogen which is a potent antioxidant and prevents oxidative stress (OS) in body. The study is being aimed to find out the status of antioxidant enzymes (AOEs) and malondialdehyde (MDA) in post-menopausal diabetic women.

METHODS

The study was conducted with a total of 70 cases, which included 35 Type 2 diabetic post-menopausal females (45 - 60 years) with diabetic CVD complication as the study group and 35 age matched type 2 diabetic postmenopausal females without CVD complication.

RESULTS

All diabetic post menopausal females with CVD had significantly higher levels of fasting plasma glucose (FPG), postprandial plasma glucose (PPPG), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), catalase (CAT), and malondialdehyde (MDA) and significantly lower levels of HDL-C, reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), and superoxide dismutase (SOD) as compared to the levels of control subjects.

CONCLUSIONS

During menopause, reduced production of estrogen causes hypertriglyceridemia, hypercholesterolemia, and hyperlipoproteinemia whose oxidation causes the accumulation of FR in the cell, which precipitates OS. Also, type 2 diabetic subjects with CVD poor glycemic control and impaired AOEs result in increased oxidative injury by failure of protective mechanisms, which further leads to oxidative stress.

Regulation of cardiac excitability by protein kinase C isozymes

Cardiac excitability and electrical activity are determined by the sum of individual ion channels, gap junctions and exchanger activities. Electrophysiological remodeling during heart disease involves changes in membrane properties of cardiomyocytes and is related to higher prevalence of arrhythmia-associated morbidity and mortality. Pharmacological and genetic manipulation of cardiac cells as well as animal models of cardiovascular diseases are used to identity changes in electrophysiological properties and the molecular mechanisms associated with the disease. Protein kinase C (PKC) and several other kinases play a pivotal role in cardiac electrophysiological remodeling. Therefore, identifying specific therapies that regulate these kinases is the main focus of current research. PKC, a family of serine/threonine kinases, has been implicated as potential signaling nodes associated with biochemical and biophysical stress in cardiovascular diseases. In this review, we describe the role of PKC isozymes that are involved in cardiac excitability and discuss both genetic and pharmacological tools that were used, their attributes and limitations. Selective and effective pharmacological interventions to normalize cardiac electrical activities and correct cardiac arrhythmias will be of great clinical benefit.

Increased IGF1 levels in relation to heart failure and cardiovascular mortality in an elderly population: impact of ACE inhibitors

OBJECTIVE

There are conflicting results regarding the association of circulating IGF1 with cardiovascular (CV) morbidity and mortality. We assessed the relationship between IGF1 levels and heart failure (HF), ischemic heart disease (IHD), and CV mortality in an elderly population taking into account the possible impact of angiotensin converting enzyme (ACE) inhibitors.

DESIGN AND METHODS

A total of 851 persons aged 66-81 years, in a rural Swedish municipality, were subjected to medical history, clinical examination, electrocardiography, echocardiography, and fasting plasma samples. They were then followed for 8 years.

RESULTS AND CONCLUSION

Patients on ACE inhibitors had higher IGF1 levels compared with those without ACE inhibitors. In patients on ACE inhibitors, higher IGF1 values were found in patients with an ejection fraction (EF) <40% compared with EF ≥40%, in patients with higher proBNP levels in quartile 4 vs 1, and in patients with IHD when compared to those without ACE inhibitors (P<0.001). In patients without ACE inhibitors, no relationship was found between IGF1 levels and HF or IHD. In multivariate regression, only ACE inhibitors, ECG changes characteristic for IHD, and gender had a significant impact on IGF1. Patients with higher IGF1 levels in quintiles 4 and 5 compared to quintiles 1 and 2 had a 50% higher risk for CV death (P=0.03). This was significant after adjustment for well-known CV risk factors and ACE inhibitors (P=0.03).

CONCLUSIONS

Our results show that treatment with ACE inhibitors in an elderly population is associated with increased IGF1 levels, especially in patients with impaired cardiac function or IHD. High IGF1 levels tend to be associated with an increased risk for CV mortality.

Effect of exercise training on the cardiovascular and biochemical parameters in women with eNOS gene polymorphism

CONTEXT

Presence of endothelial nitric oxide synthase (eNOS) gene polymorphism has been associated with cardiovascular disease (CVD) whereas exercise training (EX) promotes beneficial effects on CVD which is related to increased nitric oxide levels (NO).

OBJECTIVE

To evaluate if women with eNOS gene polymorphism at position-G894T would be less responsive to EX than those who did not carry T allele.

METHODS

Women were trained 3 days/week, 40 minutes session during 6 months. Cardio-biochemical parameters and genetic analysis were performed in a double-blind fashion.

RESULTS

Plasma NOx- levels were similar in both groups at baseline (GG genotype: 18.44±3.28 μM) and (GT+TT genotype: 17.19±2.43 μM) and after EX (GG: 29.20±4.33 and GT+TT: 27.38±3.12 μM). A decrease in blood pressure was also observed in both groups.

DISCUSSION AND CONCLUSION

The presence of eNOS polymorphism does not affect the beneficial effects of EX in women.