Role of genetic polymorphisms of ion channels in the pathophysiology of coronary microvascular dysfunction and ischemic heart disease

mir-605-3p prevents liver premetastatic niche formation by inhibiting angiogenesis via decreasing exosomal nos3 release in gastric cancer

BACKGROUND

Cancer-induced pre-metastatic niches (PMNs) play a decisive role in promoting metastasis by facilitating angiogenesis in distant sites. Evidence accumulates suggesting that microRNAs (miRNAs) exert significant influence on angiogenesis during PMN formation, yet their specific roles and regulatory mechanisms in gastric cancer (GC) remain underexplored.

METHODS

miR-605-3p was identified through miRNA-seq and validated by qRT-PCR. Its correlation with the clinicopathological characteristics and prognosis was analyzed in GC. Functional assays were performed to examine angiogenesis both in vitro and in vivo. The related molecular mechanisms were elucidated using RNA-seq, immunofluorescence, transmission electron microscopy, nanoparticle tracking analysis, enzyme-linked immunosorbent assay, luciferase reporter assays and bioinformatics analysis.

RESULTS

miR-605-3p was screened as a candidate miRNA that may regulate angiogenesis in GC. Low expression of miR-605-3p is associated with shorter overall survival and disease-free survival in GC. miR-605-3p-mediated GC-secreted exosomes regulate angiogenesis by regulating exosomal nitric oxide synthase 3 (NOS3) derived from GC cells. Mechanistically, miR-605-3p reduced the secretion of exosomes by inhibiting vesicle-associated membrane protein 3 (VAMP3) expression and affects the transport of multivesicular bodies to the GC cell membrane. At the same time, miR-605-3p reduces NOS3 levels in exosomes by inhibiting the expression of intracellular NOS3. Upon uptake of GC cell-derived exosomal NOS3, human umbilical vein endothelial cells exhibited increased nitric oxide levels, which induced angiogenesis, established liver PMN and ultimately promoted the occurrence of liver metastasis. Furthermore, a high level of plasma exosomal NOS3 was clinically associated with metastasis in GC patients.

CONCLUSIONS

miR-605-3p may play a pivotal role in regulating VAMP3-mediated secretion of exosomal NOS3, thereby affecting the formation of GC PMN and thus inhibiting GC metastasis.

Association between dietary magnesium and 10-year risk of a first hard atherosclerotic cardiovascular disease event

BACKGROUND

To test whether dietary magnesium is associated with 10-year risk of a first hard atherosclerotic cardiovascular disease event.

METHODS

In this cross-sectional study, a total of 2980 participants, aged 40 to 79 years, from the National Health and Nutrition Examination Survey 1999-2018 were analyzed. The association between dietary magnesium and 10-year risk of a first hard atherosclerotic cardiovascular disease (ASCVD) event was assessed following adjustment for clinical risk factors, including sex, age, race, educational level, body mass index (BMI), alcohol drinking, smoking, systolic blood pressure (SBP), diastolic blood pressure (DBP), hypertension treated or not, diabetes and low density lipoprotein cholesterol (LDL-C), total energy and dietary fiber. We performed multivariate linear regression models and smooth curve fittings to evaluate the associations between dietary magnesium and 10-year risk of a first hard atherosclerotic cardiovascular disease event.

RESULTS

We observed a significant inverse association between dietary magnesium and predicted 10-year risk of a first hard atherosclerotic cardiovascular disease event (β=-0.01, [95% CI: -0.01, -0.00], P = 0.0256). We divided the 10-year risk into two categories, with a statistically significant reduction of ASCVD risk when the 10-year risk ≥7.5% (β=-0.01, [95% CI: -0.01, -0.00], P = 0.0440).

CONCLUSIONS

Dietary magnesium intake was inversely associated with the predicted 10-year risk of a first hard atherosclerotic cardiovascular disease event.

Coronary microvascular dysfunction

Coronary microvascular dysfunction (CMD) is a key mechanism underlying ischemic heart disease (IHD), yet its diagnosis and treatment remain challenging. This article presents a comprehensive overview of CMD research, covering its pathogenesis, diagnostic criteria, assessment techniques, risk factors, and therapeutic strategies. Additionally, it highlights the prospects for future CMD research. The article aims at advocating early and effective intervention for CMD and improving the prognosis of IHD.

Single Nucleotide Polymorphisms in Coronary Microvascular Dysfunction

Coronary microvascular dysfunction is an underdiagnosed pathologic process that is associated with adverse clinical outcomes. There are data to suggest that coronary microvascular dysfunction, in some cases, may be genetically determined. We present an updated review of single nucleotide polymorphisms in coronary microvascular dysfunction.

Bioinformatics and Systems Biology Approach to Identify the Pathogenetic Link between Heart Failure and Sarcopenia

Despite increasing evidence that patients with heart failure (HF) are susceptible to sarcopenia, the reason for the association is not well understood. The purpose of this study is to explore further the molecular mechanism of the occurrence of this complication. Gene expression datasets for HF (GSE57345) and Sarcopenia (GSE1428) were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using 'edgeR' and "limma" packages of R, and their functions were analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Protein-protein interaction (PPI) networks were constructed and visualized using Search Tool for the Retrieval of Interacting Genes (STRING) and Cytoscape. Hub genes were selected using the plugin cytoHubba and validation with GSE76701 for HF and GSE136344 for Sarcopenia. The related pathways and molecular mechanisms of the hub genes were performed by Gene set enrichment analysis (GSEA). The statistical analyses were performed using R software. P < 0.05 was considered statistically significant. A total of 114 common DEGs were found. Pathways related to growth factor, Insulin secretion and cGMP-PKG were enriched in both HF and Sarcopenia. CYP27A1, KCNJ8, PIK3R5, TIMP2, CXCL12, KIT, and VCAM1 were found to be significant hub genes after validation, with GSEA emphasizing the importance of the hub genes in the regulation of the inflammatory response. Our study reveals that HF and Sarcopenia share common pathways and pathogenic mechanisms. These findings may suggest new directions for future research into the underlying pathogenesis.

Mitochondria in endothelial cells angiogenesis and function: current understanding and future perspectives

Endothelial cells (ECs) angiogenesis is the process of sprouting new vessels from the existing ones, playing critical roles in physiological and pathological processes such as wound healing, placentation, ischemia/reperfusion, cardiovascular diseases and cancer metastasis. Although mitochondria are not the major sites of energy source in ECs, they function as important biosynthetic and signaling hubs to regulate ECs metabolism and adaptations to local environment, thus affecting ECs migration, proliferation and angiogenic process. The understanding of the importance and potential mechanisms of mitochondria in regulating ECs metabolism, function and the process of angiogenesis has developed in the past decades. Thus, in this review, we discuss the current understanding of mitochondrial proteins and signaling molecules in ECs metabolism, function and angiogeneic signaling, to provide new and therapeutic targets for treatment of diverse cardiovascular and angiogenesis-dependent diseases.

Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA): Focus on Coronary Microvascular Dysfunction and Genetic Susceptibility

Among the most common causes of death worldwide, ischemic heart disease (IHD) is recognized to rank first. Even if atherosclerotic disease of the epicardial arteries is known as the leading cause of IHD, the presence of myocardial infarction with non-obstructive coronary artery disease (MINOCA) is increasingly recognized. Notwithstanding the increasing interest, MINOCA remains a puzzling clinical entity that can be classified by distinguishing different underlying mechanisms, which can be divided into atherosclerotic and non-atherosclerotic. In particular, coronary microvascular dysfunction (CMD), classifiable in non-atherosclerotic mechanisms, is a leading factor for the pathophysiology and prognosis of patients with MINOCA. Genetic susceptibility may have a role in primum movens in CMD. However, few results have been obtained for understanding the genetic mechanisms underlying CMD. Future studies are essential in order to find a deeper understanding of the role of multiple genetic variants in the genesis of microcirculation dysfunction. Progress in research would allow early identification of high-risk patients and the development of pharmacological, patient-tailored strategies. The aim of this review is to revise the pathophysiology and underlying mechanisms of MINOCA, focusing on CMD and actual knowledge about genetic predisposition to it.

Protection against Ischemic Heart Disease: A Joint Role for eNOS and the KATP Channel

Genetic susceptibility may influence ischemic heart disease (IHD) predisposition and affect coronary blood flow (CBF) regulation mechanisms. The aim of this study was to investigate the association among single nucleotide polymorphisms (SNPs) of genes encoding for proteins involved in CBF regulation and IHD. A total of 468 consecutive patients were enrolled and divided into three groups according to coronary angiography and intracoronary functional tests results: G1, patients with coronary artery disease (CAD); G2, patients with coronary microvascular dysfunction (CMD); and G3, patients with angiographic and functionally normal coronary arteries. A genetic analysis of the SNPs rs5215 of the potassium inwardly rectifying channel subfamily J member 11 (KCNJ11) gene and rs1799983 of the nitric oxide synthase 3 (NOS3) gene, respectively encoding for the Kir6.2 subunit of ATP sensitive potassium (K_ATP) channels and nitric oxide synthase (eNOS), was performed on peripheral whole blood samples. A significant association of rs5215_G/G of KCNJ11 and rs1799983_T/T of NOS3 genes was detected in healthy controls compared with CAD and CMD patients. Based on univariable and multivariable analyses, the co-presence of rs5215_G/G of KCNJ11 and rs1799983_T/T of NOS3 may represent an independent protective factor against IHD, regardless of cardiovascular risk factors. This study supports the hypothesis that SNP association may influence the crosstalk between eNOS and the K_ATP channel that provides a potential protective effect against IHD.

Association of KATP variants with CMD and RAP in CAD patients with increased serum lipoprotein(a) levels

CONTEXT

Refractory angina pectoris (RAP) is a specific subtype of coronary artery disease (CAD). Lipoprotein(a) [Lp(a)] and its induced coronary microvascular dysfunction (CMD) play an important role in pathogenesis of RAP, but its metabolism was mostly genetically determined. ATP-sensitive potassium channels (KATP) is involved in lipid metabolism and microvascular homeostasis, and becomes a promising target for the management of Lp(a) and its related RAP.

OBJECTIVE

To investigate associations of KATP variants with hyperlipoprotein(a)emia, CMD and RAP in CAD patients.

DESIGN, PATIENTS, SETTINGS

A total of 1,148 newly diagnosed CAD patients were prospectively selected, and divided into control [Lp(a) < 180 mg/dL] and case [Lp(a) ≥ 180 mg/dL, hyperlipoprotein(a)emia] group.

METHODS

9 KATP variants were genotyped by MassARRAY system. The expression profile of exosome-derived microRNAs (exo-miRs) was identified by next-generation sequencing, and the expression levels of differentially expressed exo-miRs were evaluated by qRT-PCR in verification cohort.

RESULTS

Three KATP variants were associated with increased risk of hyperlipoprotein(a)emia in CAD patients as follows: rs2285676 (AA + GA genotype, adjusted OR = 1.44, 95% CI: 1.10-1.88, P = 0.008), rs1799858 (CC genotype, adjusted OR = 1.33, 95% CI: 1.03-1.73, P = 0.030), and rs141294036 (CC genotype, adjusted OR = 1.43, 95% CI: 1.10-1.87, P = 0.008). Only rs141294036 was associated with increased risk of CMD (CC genotype, adjusted OR = 1.62, 95% CI: 1.23-2.13, P = 0.001), and further with increased RAP risk (CC genotype, adjusted HR = 2.05, 95% CI: 1.22-3.43, P = 0.007) after median follow-up of 50.6-months. Between the two genotypes of rs141294036, 152 exo-miRs were significantly differentially expressed, only 10 exo-miRs (miR-7110-3p, miR-548az-5p, miR-214-3p, let-7i-5p, miR-218-5p, miR-128-3p, miR-378i, miR-625-3p, miR-128-1-5p and miR-3187-3p) were further confirmed in RAP patients with hyperlipoprotein(a)emia and CMD.

CONCLUSION

KATP rs141294036 may serve a potential genetic marker for hyperlipoprotein(a)emia, CMD and RAP in CAD patients.

The efficacy and safety of Rhodiola formulation for the treatment of ischemic heart disease: A protocol for systematic review and meta-analysis

BACKGROUND

Ischemic heart disease is the main cause of heart failure, which seriously endangers the health of people and puts a huge burden on health care resources all over the world. We propose the current protocol to evaluate the effectiveness and safety of Rhodiola on ischemic heart disease, providing a reference for clinical use.

METHODS

Two research members will electronically and independently search 4 English databases (EMBASE, PubMed, National Guideline Clearinghouse, and Cochrane Central Register of Controlled Trials) and 4 Chinese databases (Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, Wanfang Database, and VIP Database) from their inception to October 2020. Quality assessment of the included randomized controlled trial was assessed using the Cochrane Collaboration's tool. All calculations were carried out with Stata 11.0 (The Cochrane Collaboration, Oxford, United Kingdom).

RESULTS

A synthesis of current evidence of Rhodiola formulation for ischemic heart disease will be provided in this protocol.

CONCLUSION

This study will provide a theoretical basis for the clinical use of Rhodiola formulation for treating ischemic heart disease.

Potential Role of eNOS Genetic Variants in Ischemic Heart Disease Susceptibility and Clinical Presentation

Background: IHD is determined by an inadequate coronary blood supply to the myocardium, and endothelial dysfunction may represent one of the main pathophysiological mechanisms involved. Genetic predisposition to endothelial dysfunction has been associated with IHD and its clinical manifestation. However, studies are often confounding and inconclusive for several reasons, such as interethnic differences. Validation of results in larger cohorts and new populations is needed. The aim of this study is to evaluate the associations between the allelic variants of the eNOS rs1799983 single-nucleotide polymorphism, IHD susceptibility and its clinical presentation. Methods: A total of 362 consecutive patients with suspected myocardial ischemia were enrolled. Patients were divided into three groups: G1, coronary artery disease (CAD); G2, coronary microvascular dysfunction (CMD); and G3, a control group with anatomically and functionally normal coronary arteries. Analysis of three allelic variants, GT, GG and TT, of rs1799983 for the NOS3 gene, encoding for eNOS, was performed. Results: rs1799983_GT was significantly more expressed by the ischemic groups (G1 and G2) compared to G3. The TT variant was significantly more expressed by the G1 group, compared to the G2 group. Among ischemic patients, GT was significantly more expressed in patients with acute coronary syndrome (ACS) presentation, compared to other clinical presentations. In the multivariate analysis, the allelic variant GT was found to potentially represent an independent predictor of IHD and ACS presentation. Conclusion: The presence of the SNP rs1799983_GT, encoding for eNOS, is an independent risk factor for IHD and, remarkably, for ACS presentation, independently of cardiovascular risk factors. These results may be useful for the prediction of IHD development, particularly with an acute clinical manifestation. They may allow the early identification of patients at high risk of developing IHD with an ACS, promoting a genetic-based prevention strategy against IHD.

Association of eNOS (G894T, rs1799983) and KCNJ11 (E23K, rs5219) gene polymorphism with coronary artery disease in North Indian population

Background

Endothelial nitric oxide synthase (eNOS) and potassium voltage-gated channel subfamily J member 11 (KCNJ11) could be the candidate genes for coronary artery disease (CAD). This study investigated the relationship of the eNOS (rs1799983) and KCNJ11 (rs5219) polymorphisms with the presence and severity of CAD in the North Indian population.

Methods

This study included 300 subjects, 150 CAD cases and 150 healthy controls. Single nucleotide polymorphism was evaluated by Polymerase chain reaction and Restriction fragment length polymorphism (PCR-RFLP). Analysis was performed by SPSS (version 21.0).

Results

We observed that KK genotype of KCNJ11E23K (rs5219) polymorphism (P=0.0001) genotypes and K allele (P=0.0001) was found to be a positive risk factor and strongly associated with CAD. In the case of eNOSG894T (rs1799983) there was no association found with CAD.

Conclusion

These results illustrate the probability of associations between SNPs and CAD although specific genetic polymorphisms affecting ion channel function and expression have still to be clarified by further investigations involving larger cohorts.

Myocardial Tissue Characterization in Heart Failure with Preserved Ejection Fraction: From Histopathology and Cardiac Magnetic Resonance Findings to Therapeutic Targets

Heart failure with preserved ejection fraction (HFpEF) is a complex clinical syndrome responsible for high mortality and morbidity rates. It has an ever growing social and economic impact and a deeper knowledge of molecular and pathophysiological basis is essential for the ideal management of HFpEF patients. The association between HFpEF and traditional cardiovascular risk factors is known. However, myocardial alterations, as well as pathophysiological mechanisms involved are not completely defined. Under the definition of HFpEF there is a wide spectrum of different myocardial structural alterations. Myocardial hypertrophy and fibrosis, coronary microvascular dysfunction, oxidative stress and inflammation are only some of the main pathological detectable processes. Furthermore, there is a lack of effective pharmacological targets to improve HFpEF patients' outcomes and risk factors control is the primary and unique approach to treat those patients. Myocardial tissue characterization, through invasive and non-invasive techniques, such as endomyocardial biopsy and cardiac magnetic resonance respectively, may represent the starting point to understand the genetic, molecular and pathophysiological mechanisms underlying this complex syndrome. The correlation between histopathological findings and imaging aspects may be the future challenge for the earlier and large-scale HFpEF diagnosis, in order to plan a specific and effective treatment able to modify the disease's natural course.

Automatic Segmentation and Cardiac Mechanics Analysis of Evolving Zebrafish Using Deep Learning

Background: In the study of early cardiac development, it is essential to acquire accurate volume changes of the heart chambers. Although advanced imaging techniques, such as light-sheet fluorescent microscopy (LSFM), provide an accurate procedure for analyzing the heart structure, rapid, and robust segmentation is required to reduce laborious time and accurately quantify developmental cardiac mechanics. Methods: The traditional biomedical analysis involving segmentation of the intracardiac volume occurs manually, presenting bottlenecks due to enormous data volume at high axial resolution. Our advanced deep-learning techniques provide a robust method to segment the volume within a few minutes. Our U-net-based segmentation adopted manually segmented intracardiac volume changes as training data and automatically produced the other LSFM zebrafish cardiac motion images. Results: Three cardiac cycles from 2 to 5 days postfertilization (dpf) were successfully segmented by our U-net-based network providing volume changes over time. In addition to understanding each of the two chambers' cardiac function, the ventricle and atrium were separated by 3D erode morphology methods. Therefore, cardiac mechanical properties were measured rapidly and demonstrated incremental volume changes of both chambers separately. Interestingly, stroke volume (SV) remains similar in the atrium while that of the ventricle increases SV gradually. Conclusion: Our U-net-based segmentation provides a delicate method to segment the intricate inner volume of the zebrafish heart during development, thus providing an accurate, robust, and efficient algorithm to accelerate cardiac research by bypassing the labor-intensive task as well as improving the consistency in the results.

Detection of Coronary Artery Disease by an Erectile Dysfunction Questionnaire

Background

Erectile dysfunction (ED) has been become an important health challenge in recent years affecting the quality of life significantly. In addition to imposed social problems, it may warn the existence of cardiovascular diseases especially that of ischemic heart disease (IHD). We aimed to investigate the association between ED and coronary artery disease (CAD) in a population of patients with stable angina based on angiographic findings.

Methods

In this cross-sectional study, among patients who are diagnosed with stable angina referring for coronary angiography (excluding those with acute coronary syndrome), 200 patients were selected. They were divided equally into two groups of case and control. The former were positively CAD patients and the latter were normal peers, with respect to angiographic results. International index of erectile function (IIEF) questionnaire was used in order to evaluate erectile function during recent four weeks. Statistical analyses of the t-test and logistic regression were performed. The significance level was considered as a P value less than 5%.

Results

The age range of the patients was 40–65 years old. The case group was significantly older (P=0.001). There was a remarkable relation between the low score from IIEF (ED) and existence of CAD. Also, the severity of ED was in a close relationship with severity of CAD. In addition, dyslipidemia in terms of high LDL and low HDL was associated with both ED and severity of CAD.

Conclusion

Other than CAD, ED could be considered as one of the manifestations of atherosclerosis. Accordingly, the IIEF questionnaire is a useful tool to early diagnosis of CAD. Also, IIEF-derived scores estimate CAD severity. We suggest subjects with low score of IIEF examine their cardiovascular health with special attention to possible existence of IHD.

Ischemic Heart Disease Pathophysiology Paradigms Overview: From Plaque Activation to Microvascular Dysfunction

Ischemic heart disease still represents a large burden on individuals and health care resources worldwide. By conventions, it is equated with atherosclerotic plaque due to flow-limiting obstruction in large-medium sized coronary arteries. However, clinical, angiographic and autoptic findings suggest a multifaceted pathophysiology for ischemic heart disease and just some cases are caused by severe or complicated atherosclerotic plaques. Currently there is no well-defined assessment of ischemic heart disease pathophysiology that satisfies all the observations and sometimes the underlying mechanism to everyday ischemic heart disease ward cases is misleading. In order to better examine this complicated disease and to provide future perspectives, it is important to know and analyze the pathophysiological mechanisms that underline it, because ischemic heart disease is not always determined by atherosclerotic plaque complication. Therefore, in order to have a more complete comprehension of ischemic heart disease we propose an overview of the available pathophysiological paradigms, from plaque activation to microvascular dysfunction.

Coronary microvascular dysfunction in hypertrophy and heart failure

Left ventricular (LV) hypertrophy (LVH) is a growth in left myocardial mass mainly caused by increased cardiomyocyte size. LVH can be a physiological adaptation to physical exercise or a pathological condition either primary, i.e. genetic, or secondary to LV overload. Patients with both primary and secondary LVH have evidence of coronary microvascular dysfunction (CMD). The latter is mainly due to capillary rarefaction and adverse remodelling of intramural coronary arterioles due to medial wall thickening with an increased wall/lumen ratio. An important feature of this phenomenon is the diffuse nature of this remodelling, which generally affects the coronary microvessels in the whole of the left ventricle. Patients with LVH secondary to arterial hypertension can develop both heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF). These patients can develop HFrEF via a 'direct pathway' with an interval myocardial infarction and also in its absence. On the other hand, patients can develop HFpEF that can then progress to HFrEF with or without interval myocardial infarction. A similar evolution towards LV dysfunction and both HFpEF and HFrEF can occur in patients with hypertrophic cardiomyopathy, the most common genetic cardiomyopathy with a phenotype characterized by massive LVH. In this review article, we will discuss both the experimental and clinical studies explaining the mechanisms responsible for CMD in LVH as well as the evidence linking CMD with HFpEF and HFrEF.

Susceptibility to ischaemic heart disease: Focusing on genetic variants for ATP-sensitive potassium channel beyond traditional risk factors

AIMS

Ischaemic heart disease is classically associated with coronary artery disease. Recent evidences showed the correlation between coronary microvascular dysfunction and ischaemic heart disease, even independently of coronary artery disease. Ion channels represent the final effectors of blood flow regulation mechanisms and their genetic variants, in particular of Kir6.2 subunit of the ATP-sensitive potassium channel (KATP), are reported to be involved in ischaemic heart disease susceptibility. The aim of the present study is to evaluate the role of KATP channel and its genetic variants in patients with ischaemic heart disease and evaluate whether differences exist between coronary artery disease and coronary microvascular dysfunction.

METHODS

A total of 603 consecutive patients with indication for coronary angiography due to suspected myocardial ischaemia were enrolled. Patients were divided into three groups: coronary artery disease (G1), coronary microvascular dysfunction (G2) and normal coronary arteries (G3). Analysis of four single nucleotide polymorphisms (rs5215, rs5216, rs5218 and rs5219) of the KCNJ11 gene encoding for Kir6.2 subunit of the KATP channel was performed.

RESULTS

rs5215 A/A and G/A were significantly more represented in G1, while rs5215 G/G was significantly more represented in G3, rs5216 G/G and C/C were both more represented in G3, rs5218 C/C was more represented in G1 and rs5219 G/A was more represented in G1, while rs5219 G/G was significantly more represented in G2. At multivariate analysis, single nucleotide polymorphism rs5215_G/G seems to represent an ischaemic heart disease independent protective factor.

CONCLUSIONS

These results suggest the potential role of KATP genetic variants in ischaemic heart disease susceptibility, as an independent protective factor. They may lead to a future perspective for gene therapy against ischaemic heart disease.

Physiological Stratification of Patients With Angina Due to Coronary Microvascular Dysfunction

BACKGROUND

Coronary microvascular dysfunction (CMD) is defined by diminished flow reserve. Functional and structural CMD endotypes have recently been described, with normal and elevated minimal microvascular resistance, respectively.

OBJECTIVES

This study determined the mechanism of altered resting and maximal flow in CMD endotypes.

METHODS

A total of 86 patients with angina but no obstructive coronary disease underwent coronary pressure and flow measurement during rest, exercise, and adenosine-mediated hyperemia and were classified as the reference group or as patients with CMD by a coronary flow reserve threshold of 2.5; functional or structural endotypes were distinguished by a hyperemic microvascular resistance threshold of 2.5 mm Hg/cm/s. Endothelial function was assessed by forearm blood flow (FBF) response to acetylcholine, and nitric oxide synthase (NOS) activity was defined as the inverse of FBF reserve to NG-monomethyl-L-arginine.

RESULTS

Of the 86 patients, 46 had CMD (28 functional, 18 structural), and 40 patients formed the reference group. Resting coronary blood flow (CBF) (24.6 ± 2.0 cm/s vs. 16.6 ± 3.9 cm/s vs. 15.1 ± 4.7 cm/s; p < 0.001) and NOS activity (2.27 ± 0.96 vs. 1.77 ± 0.59 vs. 1.30 ± 0.16; p < 0.001) were higher in the functional group compared with the structural CMD and reference groups, respectively. The structural group had lower acetylcholine FBF augmentation than the functional or reference group (2.1 ± 1.8 vs. 4.1 ± 1.7 vs. 4.5 ± 2.0; p < 0.001). On exercise, oxygen demand was highest (rate-pressure product: 22,157 ± 5,497 beats/min/mm Hg vs. 19,519 ± 4,653 beats/min/mm Hg vs. 17,530 ± 4,678 beats/min/mm Hg; p = 0.004), but peak CBF was lowest in patients with structural CMD compared with the functional and reference groups.

CONCLUSIONS

Functional CMD is characterized by elevated resting flow that is linked to enhanced NOS activity. Patients with structural CMD have endothelial dysfunction, which leads to diminished peak CBF augmentation and increased demand during exercise. The value of pathophysiologically stratified therapy warrants investigation.

Ischemic Heart Disease and Heart Failure: Role of Coronary Ion Channels

Heart failure is a complex syndrome responsible for high rates of death and hospitalization. Ischemic heart disease is one of the most frequent causes of heart failure and it is normally attributed to coronary artery disease, defined by the presence of one or more obstructive plaques, which determine a reduced coronary blood flow, causing myocardial ischemia and consequent heart failure. However, coronary obstruction is only an element of a complex pathophysiological process that leads to myocardial ischemia. In the literature, attention paid to the role of microcirculation, in the pathophysiology of ischemic heart disease and heart failure, is growing. Coronary microvascular dysfunction determines an inability of coronary circulation to satisfy myocardial metabolic demands, due to the imbalance of coronary blood flow regulatory mechanisms, including ion channels, leading to the development of hypoxia, fibrosis and tissue death, which may determine a loss of myocardial function, even beyond the presence of atherosclerotic epicardial plaques. For this reason, ion channels may represent the link among coronary microvascular dysfunction, ischemic heart disease and consequent heart failure.

Mixture of MMP-2, MLC, and NOS Inhibitors Affects NO Metabolism and Protects Heart from Cardiac I/R Injury

Objectives

Coronary reperfusion procedure leads to ischemia/reperfusion injury of the heart (IRI). IRI arises from increased degradation of myosin light chains and increased activity of matrix metalloproteinase 2 (MMP-2). Increased production of toxic peroxynitrite (ONOO^-) during oxidative stress is a source of increased nitration/nitrosylation of contractile proteins, which enhance their degradation through MMP-2. Hence, an imbalance in nitric oxide (NO) metabolism along with oxidative stress is an important factor contributing to pathophysiology of cardiovascular disorders, including myocardial infarction. The aim of the current study was to provide an important insight into understanding the interaction of iNOS, eNOS, and ADMA during oxidative stress and to propose the beneficial therapy to modulate this interaction. Material and Methods. Pathogen-free Wistar rats were used in this study as a surrogate heart model ex vivo. Rat hearts perfused using the Langendorff method were subjected to global no-flow ischemia with or without administration of DOXY (1 µM), ML-7 (0.5 µM), and L-NAME (2 µM) mixture. Haemodynamic parameters of heart function, markers of I/R injury, tissue expression of iNOS, eNOS, and phospho-eNOS, asymmetric dimethylarginine, and NO production as well as MMP-2 activity were measured.

Results

Mechanical heart function and coronary flow (CF) were decreased in the hearts subjected to I/R. Treatment of the hearts with the tested mixture resulted in a recovery of mechanical function due to decreased activity of MMP-2. An infusion of Doxy, ML-7, and L-NAME mixture into I/R hearts decreased the expression of iNOS, eNOS, and phospho-eNOS and in consequence reduced ADMA expression. Decreased ADMA production led to enhanced NO synthesis and improvement of cardiac function at 85% of aerobic control.

Conclusions

Synergistic effect of the multidrug therapy with the subthreshold doses allows addressing a few pathways of I/R injury simultaneously to achieve protection of cardiac function during I/R.

Real-Time In Vivo Imaging of Mouse Left Ventricle Reveals Fluctuating Movements of the Intercalated Discs

Myocardial contraction is initiated by action potential propagation through the conduction system of the heart. It has been thought that connexin 43 in the gap junctions (GJ) within the intercalated disc (ID) provides direct electric connectivity between cardiomyocytes (electronic conduction). However, recent studies challenge this view by providing evidence that the mechanosensitive cardiac sodium channels Na_v1.5 localized in perinexii at the GJ edge play an important role in spreading action potentials between neighboring cells (ephaptic conduction). In the present study, we performed real-time confocal imaging of the CellMask-stained ID in the living mouse heart in vivo. We found that the ID structure was not rigid. Instead, we observed marked flexing of the ID during propagation of contraction from cell to cell. The variation in ID length was between ~30 and ~42 μm (i.e., magnitude of change, ~30%). In contrast, tracking of α-actinin-AcGFP revealed a comparatively small change in the lateral dimension of the transitional junction near the ID (i.e., magnitude of change, ~20%). The present findings suggest that, when the heart is at work, mechanostress across the perinexii may activate Na_v1.5 by promoting ephaptic conduction in coordination with electronic conduction, and, thereby, efficiently transmitting excitation-contraction coupling between cardiomyocytes.

Genetic Discovery of ATP-Sensitive K+ Channels in Cardiovascular Diseases

The ATP-sensitive K⁺ (K_ATP) channels are hetero-octameric protein complexes comprising 4 pore-forming (Kir6.x) subunits and 4 regulatory sulfonylurea receptor (SURx) subunits. They are prominent in myocytes, pancreatic β cells, and neurons and link cellular metabolism with membrane excitability. Using genetically modified animals and genomic analysis in patients, recent studies have implicated certain ATP-sensitive K⁺ channel subtypes in physiological and pathological processes in a variety of cardiovascular diseases. In this review, we focus on the causal relationship between ATP-sensitive K⁺ channel activity and pathophysiology in the cardiovascular system, particularly from the perspective of genetic changes in human and animal models.

Advanced Heart Failure and End-Stage Heart Failure: Does a Difference Exist

Advanced heart failure (AdHF) represents a challenging aspect of heart failure patients. Because of worsening clinical symptoms, high rates of re-hospitalization and mortality, AdHF represents an unstable condition where standard treatments are inadequate and additional interventions must be applied. A heart transplant is considered the optimal therapy for AdHF, but the great problem linked to the scarcity of organs and long waiting lists have led to the use of mechanical circulatory support with ventricular-assist device (VAD) as a destination therapy. VAD placement improves the prognosis, functional status, and quality of life of AdHF patients, with high rates of survival at 1 year, similar to transplant. However, the key element is to select the right patient at the right moment. The complete assessment must include a careful clinical evaluation, but also take into account psychosocial factors that are of crucial importance in the out-of-hospital management. It is important to distinguish between AdHF and end-stage HF, for which advanced therapy interventions would be unreasonable due to severe and irreversible organ damage and, instead, palliative care should be preferred to improve quality of life and relief of suffering. The correct selection of patients represents a great issue to solve, both ethically and economically.

PREDICTORS OF WEIGHT LOSS IN PATIENTS WITH CHRONIC HEART FAILURE AND REDUSED LEFT VENTRICULAR EJECTION FRACTION

Chronic heart failure (CHF) is a heterogeneous syndrome with a poor prognosis. Aim of the work – to define predictors of body weight (BW) loss in patients with CHF and a reduced left ventricular ejection fraction (LVEF). Materials and methods. 120 patients with stable CHF and LVEF ≤35 %, II-IV NYHA class were examined. Patients were divided into two groups according to the value of BW loss for 6 months: the first group - loss of BW <6 %, the second - ≥ 6 %. Results. Out of the 120 patients who were studied, a BW loss of ≥ 6 % occurred in 59 (49.2 %) patients. According to the results of binary logistic regression, predictors of BW loss of ≥6 % in patients with CHF and LVEF ≤ 35 % were: age, coronary heart disease, anaemia, and the number of hospitalizations over the last year. People with poorer quality of life, bigger number of points on the Beck depression scale and DEFS, with lower levels of physical activity and worse endothelium-dependent vasodilator response; higher sizes of the right atrium, right ventricle, and pulmonary artery systolic pressure, E / E '. Higher levels of C-reactive protein (CRP), uric acid are associated with a risk of losing BW≥6 %. Conclusions. Weight loss ≥ 6 % is observed in 49.2 % of patients with CHF and LVEF≤35 %. According to multivariate analysis, independent predictors of BW loss of ≥6 % in patients with CHF and LVEF≤35 % are age, CRP level, III-IV NYHA class, lower cholesterol levels, as well as lower rates of flow-dependent vasodilator response and hip circumference.

Endothelial Dysfunction in Chronic Heart Failure: Assessment, Findings, Significance, and Potential Therapeutic Targets

Chronic heart failure (CHF) is a complex syndrome that results from structural and functional disturbances that affect the ability of the heart to supply oxygen to tissues. It largely affects and reduces the patient's quality of life, socio-economic status, and imposes great costs on health care systems worldwide. Endothelial dysfunction (ED) is a newly discovered phenomenon that contributes greatly to the pathophysiology of numerous cardiovascular conditions and commonly co-exists with chronic heart failure. However, the literature lacks clarity as to which heart failure patients might be affected, its significance in CHF patients, and its reversibility with pharmacological and non-pharmacological means. This review will emphasize all these points and summarize them for future researchers interested in vascular pathophysiology in this particular patient population. It will help to direct future studies for better characterization of these two phenomena for the potential discovery of therapeutic targets that might reduce future morbidity and mortality in this "at risk" population.

Prevention of Cardiovascular Disease: Screening for Magnesium Deficiency

Magnesium is an essential mineral naturally present in the human body, where it acts as cofactor in several enzymatic reactions. Magnesium is a key cardiovascular regulator, which maintains electrical, metabolic, and vascular homeostasis. Moreover, magnesium participates in inflammation and oxidative processes. In fact, magnesium deficiency is involved in the pathophysiology of arterial hypertension, diabetes mellitus, dyslipidemia, metabolic syndrome, endothelial dysfunction, coronary artery disease, cardiac arrhythmias, and sudden cardiac death. In consideration of the great public-health impact of cardiovascular disease, the recognition of the negative effects of magnesium deficiency suggests the possible role of hypomagnesaemia as cardiovascular risk factor and the use of serum magnesium level for the screening and prevention of cardiovascular risk factors and cardiovascular diseases. Moreover, it might help with the identification of new therapeutical strategies for the management of cardiovascular disease through magnesium supplementation.

Xenopus Oocyte's Conductance for Bioactive Compounds Screening and Characterization

Background: Astaxanthin (ATX) is a lipophilic compound found in many marine organisms. Studies have shown that ATX has many strong biological properties, including antioxidant, antiviral, anticancer, cardiovascular, anti-inflammatory, neuro-protective and anti-diabetic activities. However, no research has elucidated the effect of ATX on ionic channels. ATX can be extracted from shrimp by-products. Our work aims to characterize ATX cell targets to lend value to marine by-products. Methods: We used the Xenopus oocytes cell model to characterize the pharmacological target of ATX among endogenous Xenopus oocytes’ ionic channels and to analyze the effects of all carotenoid-extract samples prepared from shrimp by-products using a supercritical fluid extraction (SFE) method. Results: ATX inhibits amiloride-sensitive sodium conductance, xINa, in a dose-dependent manner with an IC50 of 0.14 µg, a maximum inhibition of 75% and a Hill coefficient of 0.68. It does not affect the potential of half activation, but significantly changes the kinetics, according to the slope factor values. The marine extract prepared from shrimp waste at 10 µg inhibits xINa in the same way as ATX 0.1 µg does. When ATX was added to the entire extract at 10 µg, inhibition reached that induced with ATX 1 µg. Conclusions: ATX and the shrimp Extract inhibit amiloride-sensitive sodium channels in Xenopus oocytes and the TEVC method makes it possible to measure the ATX inhibitory effect in bioactive SFE-Extract samples.

Myocardial Ischemia and Diabetes Mellitus: Role of Oxidative Stress in the Connection between Cardiac Metabolism and Coronary Blood Flow

Ischemic heart disease (IHD) has several risk factors, among which diabetes mellitus represents one of the most important. In diabetic patients, the pathophysiology of myocardial ischemia remains unclear yet: some have atherosclerotic plaque which obstructs coronary blood flow, others show myocardial ischemia due to coronary microvascular dysfunction in the absence of plaques in epicardial vessels. In the cross-talk between myocardial metabolism and coronary blood flow (CBF), ion channels have a main role, and, in diabetic patients, they are involved in the pathophysiology of IHD. The exposition to the different cardiovascular risk factors and the ischemic condition determine an imbalance of the redox state, defined as oxidative stress, which shows itself with oxidant accumulation and antioxidant deficiency. In particular, several products of myocardial metabolism, belonging to oxidative stress, may influence ion channel function, altering their capacity to modulate CBF, in response to myocardial metabolism, and predisposing to myocardial ischemia. For this reason, considering the role of oxidative and ion channels in the pathophysiology of myocardial ischemia, it is allowed to consider new therapeutic perspectives in the treatment of IHD.

Effects of polymorphisms in APOA5 on the plasma levels of triglycerides and risk of coronary heart disease in Jilin, northeast China: a case-control study

OBJECTIVE

The goal of this study is to investigate the associations of apolipoprotein A5 (APOA5) polymorphisms with coronary artery disease (CAD) in a Chinese population.

METHOD

This case-control study included 710 subjects (355 patients with CAD and 355 controls) who were recruited from a cross-sectional study. Three single nucleotide polymorphisms (SNPs) rs662799 (-1131T>C), rs651821 (-3A>G) and rs2075291 (G185C) in APOA5 were selected and genotyped using the matrix-assisted laser desorption ioniasation time of flight mass spectrometry technology. The χ² test and haplotype analysis were performed to analyse the associations between APOA5 SNPs and CAD using the SPSS V.22.0 software package and the online SNPStats program.

RESULTS

APOA5 SNPs rs662799 and rs651821 exhibited significant differences in genotype and allele distributions between patients with CAD and control subjects. The SNP rs662799 was significantly correlated with an increased risk of CAD when a dominant model was considered. The SNP rs651821 was significantly correlated with an increased risk of CAD when a codominant model was considered. Moreover, the variant C alleles of rs662799 and the variant G alleles of the rs651821 polymorphism were significantly correlated with increased plasma triglyceride (TG) levels in the CAD group (all p<0.05). Additionally, a mediating effect of TG on the associations between the APOA5 rs662799 and rs651821 polymorphisms and CAD was observed.

CONCLUSION

Based on these data, variants of the APOA5 gene are associated with CAD susceptibility and may modulate plasma TG levels among a Chinese population.

Genetic Markers for Coronary Artery Disease

Coronary artery disease (CAD) and myocardial infarction (MI) are recognized as leading causes of mortality in developed countries. Although typically associated with behavioral risk factors, such as smoking, sedentary lifestyle, and poor dietary habits, such vascular phenotypes have also long been recognized as being related to genetic background. We review the currently available data concerning genetic markers for CAD in English and non-English articles with English abstracts published between 2003 and 2018. As genetic testing is increasingly available, it may be possible to identify adequate genetic markers representing the risk profile and to use them in a clinical setting.

Association between the PPP1R3B polymorphisms and serum lipid traits, the risk of coronary artery disease and ischemic stroke in a southern Chinese Han population

Background

Little is known about the association of the protein phosphatase 1 regulatory subunit 3B gene (PPP1R3B) single nucleotide polymorphisms (SNPs) and serum lipid levels, the risk of coronary artery disease (CAD) and ischemic stroke (IS) in the Chinese populations. This study detected such association in a Southern Chinese Han population.

Methods

Genotypes of 4 novel PPP1R3B SNPs (rs12785, rs330910, rs330915 and rs9949) in 1704 Han Chinese (CAD, 556; IS, 531 and control, 617) were determined by the Snapshot technology.

Results

The rs12785A and rs9949A allele frequency was higher in both CAD/IS patients than in controls. The rs330910T and rs330915T allele frequency was also higher in CAD patients than in controls. The rs330910T allele carriers in controls had lower serum low-density lipoprotein cholesterol (LDL-C) levels than the rs330910T allele non-carriers (P < 0.0014). The rs12785A, rs9949A and rs330910T allele carriers were associated with an increased risk of CAD (P = 0.008–0.004). There was strong linkage disequilibrium among the 4 SNPs in the controls and CAD/IS patients. The T-A-A-G haplotype was associated with a decreased risk of CAD and IS, whereas the A-A-T-A haplotype was associated with an increased risk for IS. Haplotype-environment interactions on the risk of CAD and IS were also observed.

Conclusions

Several PPP1R3B polymorphisms were associated with serum LDL-C levels, the risk of CAD and IS in the Southern Chinese Han population. But these findings still need to be confirmed in the other populations with larger sample sizes.

Electronic supplementary material

The online version of this article (10.1186/s12986-018-0266-y) contains supplementary material, which is available to authorized users.

Diabetes Mellitus and Ischemic Heart Disease: The Role of Ion Channels

Diabetes mellitus is one the strongest risk factors for cardiovascular disease and, in particular, for ischemic heart disease (IHD). The pathophysiology of myocardial ischemia in diabetic patients is complex and not fully understood: some diabetic patients have mainly coronary stenosis obstructing blood flow to the myocardium; others present with coronary microvascular disease with an absence of plaques in the epicardial vessels. Ion channels acting in the cross-talk between the myocardial energy state and coronary blood flow may play a role in the pathophysiology of IHD in diabetic patients. In particular, some genetic variants for ATP-dependent potassium channels seem to be involved in the determinism of IHD.

In vivo immunoprotective role of Indigofera tinctoria and Scoparia dulcis aqueous extracts against chronic noise stress induced immune abnormalities in Wistar albino rats

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Chronic noise stress was suppressed both innate and adaptive immune response of wistar albino rats.

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Noise stress also caused DNA damage in the liver and spleen tissues.

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Aqueous extracts of I. tinctoria and S. dulcis prevent the immune abnormalities caused by noise stress.

Indigofera tinctoria and Scoparia dulcis are being widely used in Indian folk medicine for the treatment of various disorders. Environmental noise pollution is thought to be an important factor for many health problems and it causes immune abnormalities. In the present study immune-regulating potential of I. tinctoria and S. dulcis aqueous extracts on innate and adaptive immune system of wistar albino rats was evaluated during normal and chronic noise induced stress conditions. The results demonstrated that both I. tinctoria and S. dulcis aqueous extracts (200 mg/kg b.w) showed immunostimulant effect on both innate and adaptive immune response of wistar albino rat compared to control group under normal condition. The noise stress (100 dB for 1 h, 20 days) induced animals showed suppressive effects on immune response by decreasing macrophage phagocytosis, antibody secretion by spleen cells, humoral immune response, proliferation of lymphocytes, cytotoxicity, TNF α expression, granzyme B and perforin expression in splenic NK cells. Similarly, noise stress also caused DNA damage in tissues. However, the suppressed effects induced by noise stress on rat immune system were significantly prevented by oral administration of both I. tinctoria and S. dulcis aqueous extracts. Considering all these results it is suggested that the selected medicinal plant’s aqueous extracts have the potential to prevent the effects of noise stress induced rat immune system and explore a strong immunostimulant potential applicable to clinical practices.

The effect of MVK-MMAB variants, their haplotypes and G×E interactions on serum lipid levels and the risk of coronary heart disease and ischemic stroke

Aim

This study aimed to detect the association of the mevalonate kinase (MVK) and methylmalonic aciduria (cobalamin deficiency) cblB type (MMAB) gene variants, their haplotypes, and gene-environment (G×E) interactions on serum lipid levels and the risk of coronary heart disease (CHD) and ischemic stroke (IS) in a Chinese Han population.

Methods

Genotyping of the rs3759387, rs7134594, rs877710 and rs9593 SNPs in 846 CHD and 869 IS patients and 847 healthy controls was performed by PCR-RFLP and Sanger sequencing. Logistic regression and factor regression were used to investigate the association of 4 MVK-MMAB SNPs and serum lipid levels and the risk of CHD and IS.

Results

The genotypic and allelic frequencies of the rs3759387 and rs7134594 SNPs differed between controls and patients (P < 0.0125-0.001). The rs3759387 SNP was associated with the risk of CHD and IS in different genetic models. The A-T-G-A and C-T-C-T haplotypes were associated with increased risk of CHD. The haplotype of A-T-G-A was associated with an increased risk of IS, whereas the C-T-G-A haplotype was associated with a decreased risk of IS. Interactions of C-T-C-T-smoking or C-T-C-T-age on the risk of CHD, and A-T-G-A-hypertension or A-T-G-A-age on the risk of IS were also observed. The subjects with the rs3759387AA genotype in controls had lower high-density lipoprotein cholesterol (HDL-C) levels than did the subjects with AC/CC genotypes. Several SNPs interacted with alcohol consumption and cigarette smoking to increase serum HDL-C and apolipoprotein A1 levels, but they interacted with body mass index ≥ 24 kg/m² to decrease serum HDL-C and apolipoprotein A1 levels.

Conclusion

Several MVK-MMAB variants, especially the rs3759387 SNP, 4 main haplotypes, and G×E interactions were associated with serum lipid levels and the risk of CHD and IS in a Chinese Han population.

A role of the endothelial nitric oxide system in acute renal colic caused by ureteral stone

BACKGROUND AND AIMS

Endothelial nitric oxide synthase gene polymorphisms play a role in some pathophysiological processes. In this study, the possible effects of endothelial nitric oxide synthase gene polymorphisms on ureteral stone disease in patients who were admitted to the emergency department with severe pain due to renal colic are examined.

MATERIALS AND METHODS

The study groups were designed as controls and patients. The control group was formed from the healthy volunteers who applied to the blood center next to the emergency service. The patient group comprised patients who were diagnosed with ureteral stone disease with severe pain. All of the genetic studies were based on extracted peripheral blood samples using the necessary procedures from the Genome and Stem Cell Center at Erciyes University (GENKOK). The data were analyzed with SPSS (IBM, ver 20, United Sate).

RESULTS

The study group comprised 62 females and 138 males, and the control group comprised 64 females and 136 males. All of the stones that caused renal colic were found to be localized in the ureters and the ureterovesical junction. The genotypes of the intron 4 polymorphism were found to be as follows: 4a/4a in 10 people, 4b/4a in 115, and 4b/4b in 275 people. The GG genotype of the eNOS-G894T polymorphism was found in 108 patients in the study group and in117 of the healthy individuals. There was no statistically significant difference between the two groups regarding these data.

CONCLUSION

Although this study is the first in the literature to examine the relationship between renal colic and endothelial nitric oxide synthase gene polymorphisms, our study demonstrated that no relation was found.

Effect of Glucocorticoids on Ultrastructure of Myocardial Muscle in the Course of Experimentally Induced Acute Myocardial Ischemia

The search for effective methods of myocardial cytoprotection against ischemia is the most significant issue in modern cardiology and cardiac surgery. Glucocorticoids are deemed very strong modulators of inflammatory response and thus can potentially protect heart muscle from postreperfusion injury and myocardial ischemia during cardiac surgery. Ultrastructural examination of the left ventricle heart samples revealed that the intravenous application of dexamethasone and hydrocortisone proved to exert cytoprotective effect on cardiomyocytes during experimentally induced acute ischemia in rats.

Kv1.3 channels facilitate the connection between metabolism and blood flow in the heart

The connection between metabolism and flow in the heart, metabolic dilation, is essential for cardiac function. We recently found redox-sensitive Kv1.5 channels play a role in coronary metabolic dilation; however, more than one ion channel likely plays a role in this process as animals null for these channels still showed limited coronary metabolic dilation. Accordingly, we examined the role of another Kv1 family channel, the energetically linked Kv1.3 channel, in coronary metabolic dilation. We measured myocardial blood flow (contrast echocardiography) during norepinephrine-induced increases in cardiac work (heart rate x mean arterial pressure) in WT, WT mice given correolide (preferential Kv1.3 antagonist), and Kv1.3-null mice (Kv1.3-/- ). We also measured relaxation of isolated small arteries mounted in a myograph. During increased cardiac work, myocardial blood flow was attenuated in Kv1.3-/- and in correolide-treated mice. In isolated vessels from Kv1.3-/- mice, relaxation to H2 O2 was impaired (vs WT), but responses to adenosine and acetylcholine were equivalent to WT. Correolide reduced dilation to adenosine and acetylcholine in WT and Kv1.3-/- , but had no effect on H2 O2 -dependent dilation in vessels from Kv1.3-/- mice. We conclude that Kv1.3 channels participate in the connection between myocardial blood flow and cardiac metabolism.

Homocysteine concentration in coronary artery disease: Influence of three common single nucleotide polymorphisms

BACKGROUND AND AIMS

Whether single nucleotide polymorphisms (SNPs) of homocysteine metabolism enzymes influence the rate of cardiovascular (CV) events in coronary artery disease (CAD) patients remains controversial.

METHODS AND RESULTS

In this analysis, 1126 subjects from the AtheroGene study with CAD and 332 control subjects without known CAD were included. The following SNPs were investigated: methylentetrahydrofolate reductase (MTHFR-C667T), methionin synthetase (MS-D919G), and cystathionin beta synthetase (CBS-I278T). The endpoint was the combination of cardiovascular death, stroke, and non-fatal myocardial infarction (N = 286). The median follow-up time was 6.4 years. Kaplan-Meier curve analysis showed an increasing event rate with rising homocysteine levels (p < 0.001) in CAD patients. Further, in Cox-Regression analysis homocysteine was a predictor of the endpoint with a hazard ratio (HR) of 6.5 (95% CI: 2.9-14.6, p < 0.001) in the adjusted model including cardiovascular risk factors. Of the three SNPs, homozygous MTHFR SNP increased homocysteine levels significantly in patients with CAD and individuals without CAD (both p < 0.001). The SNPs in MS and CBS were not related to relevant changes in homocysteine levels in CAD patients or controls. The different SNPs of MTHFR, MS, and CBS were not related to an increased event rate.

CONCLUSION

Homocysteine level is a strong predictor of CV events. Subjects with and without CAD and SNPs in the enzyme MTHFR had increased homocysteine levels. This was not observed for MS and CBS SNPs. Although MTHFR SNPs alter homocysteine levels in patients and controls, these polymorphisms had no impact on prognosis in CAD patients.

New Treatment Strategies for Alcohol-Induced Heart Damage

High-dose alcohol misuse induces multiple noxious cardiac effects, including myocyte hypertrophy and necrosis, interstitial fibrosis, decreased ventricular contraction and ventricle enlargement. These effects produce diastolic and systolic ventricular dysfunction leading to congestive heart failure, arrhythmias and an increased death rate. There are multiple, dose-dependent, synchronic and synergistic mechanisms of alcohol-induced cardiac damage. Ethanol alters membrane permeability and composition, interferes with receptors and intracellular transients, induces oxidative, metabolic and energy damage, decreases protein synthesis, excitation-contraction coupling and increases cell apoptosis. In addition, ethanol decreases myocyte protective and repair mechanisms and their regeneration. Although there are diverse different strategies to directly target alcohol-induced heart damage, they are partially effective, and can only be used as support medication in a multidisciplinary approach. Alcohol abstinence is the preferred goal, but control drinking is useful in alcohol-addicted subjects not able to abstain. Correction of nutrition, ionic and vitamin deficiencies and control of alcohol-related systemic organ damage are compulsory. Recently, several growth factors (myostatin, IGF-1, leptin, ghrelin, miRNA, and ROCK inhibitors) and new cardiomyokines such as FGF21 have been described to regulate cardiac plasticity and decrease cardiac damage, improving cardiac repair mechanisms, and they are promising agents in this field. New potential therapeutic targets aim to control oxidative damage, myocyte hypertrophy, interstitial fibrosis and persistent apoptosis In addition, stem-cell therapy may improve myocyte regeneration. However, these strategies are not yet approved for clinical use.

Critical contribution of KV1 channels to the regulation of coronary blood flow

Ion channels in smooth muscle control coronary vascular tone, but the identity of the potassium channels involved requires further investigation. The purpose of this study was to evaluate the functional role of KV1 channels on porcine coronary blood flow using the selective antagonist correolide. KV1 channel gene transcripts were found in porcine coronary arteries, with KCNA5 (encoding KV1.5) being most abundant (P < 0.001). Immunohistochemical staining demonstrated KV1.5 protein in the vascular smooth muscle layer of both porcine and human coronary arteries, including microvessels. Whole-cell patch-clamp experiments demonstrated significant correolide-sensitive (1-10 µM) current in coronary smooth muscle. In vivo studies included direct intracoronary infusion of vehicle or correolide into a pressure-clamped left anterior descending artery of healthy swine (n = 5 in each group) with simultaneous measurement of coronary blood flow. Intracoronary correolide (~0.3-3 µM targeted plasma concentration) had no effect on heart rate or systemic pressure, but reduced coronary blood flow in a dose-dependent manner (P < 0.05). Dobutamine (0.3-10 µg/kg/min) elicited coronary metabolic vasodilation and intracoronary correolide (3 µM) significantly reduced coronary blood flow at any given level of myocardial oxygen consumption (P < 0.001). Coronary artery occlusions (15 s) elicited reactive hyperemia and correolide (3 µM) reduced the flow volume repayment by approximately 30 % (P < 0.05). Taken together, these data support a major role for KV1 channels in modulating baseline coronary vascular tone and, perhaps, vasodilation in response to increased metabolism and transient ischemia.

The Human Microcirculation: Regulation of Flow and Beyond

The microcirculation is responsible for orchestrating adjustments in vascular tone to match local tissue perfusion with oxygen demand. Beyond this metabolic dilation, the microvasculature plays a critical role in modulating vascular tone by endothelial release of an unusually diverse family of compounds including nitric oxide, other reactive oxygen species, and arachidonic acid metabolites. Animal models have provided excellent insight into mechanisms of vasoregulation in health and disease. However, there are unique aspects of the human microcirculation that serve as the focus of this review. The concept is put forth that vasculoparenchymal communication is multimodal, with vascular release of nitric oxide eliciting dilation and preserving normal parenchymal function by inhibiting inflammation and proliferation. Likewise, in disease or stress, endothelial release of reactive oxygen species mediates both dilation and parenchymal inflammation leading to cellular dysfunction, thrombosis, and fibrosis. Some pathways responsible for this stress-induced shift in mediator of vasodilation are proposed. This paradigm may help explain why microvascular dysfunction is such a powerful predictor of cardiovascular events and help identify new approaches to treatment and prevention.

Chromosome 9p21 and ABCA1 Genetic Variants and Their Interactions on Coronary Heart Disease and Ischemic Stroke in a Chinese Han Population

The single nucleotide polymorphisms (SNPs) related to both coronary heart disease (CHD) and ischemic stroke (IS) in Chinese individuals have not been identified definitely. This study was developed to evaluate the genetic susceptibility to CHD and IS on the chromosome 9p21 and the adenosine triphosphate (ATP)-binding cassette transporter A1 genes (ABCA1) in a Chinese Han population. Genotypes of the rs1333040, rs1333042, rs4977574, rs2066715 and rs2740483 SNPs were determined in 1134 unrelated patients (CHD, 565 and IS, 569) and 541 controls. The frequencies of the rs4977574 genotypes and alleles between CHD and control groups, and the rs2740483 genotypes and alleles between IS and control groups were different (p = 0.006–0.001). The subjects with rs1333042GG genotype and the carriers of the rs4977574G allele were associated with increased risk of CHD. The carriers of the rs4977574G allele were associated with increased risk of IS. However, the carriers of the rs2740483C allele had lower risk of IS than the non-carriers of the rs2740483C allele after controlling for potential confounders. The rs4977574GG-age (>60 year) interaction increased the risk of CHD (p = 0.022), whereas the rs2740483CG/CC-body mass index (>24 kg/m²) interaction decreased the risk of IS (p = 0.035). The interactions of rs1333040-rs1333042 on the risk of CHD and IS were relatively strong, whereas the interactions of rs1333040-rs1333042-rs2066715 and rs1333040-rs1333042-rs2066715-rs2740483 on the risk of CHD, and rs1333040-rs1333042-rs4977574 and rs1333040-rs1333042-rs4977574-rs2740483 on the risk of IS were relatively weak. These findings suggest that some common variants on the chromosome 9p21 and ABCA1 and their interactions may significantly modify the risk of CHD and IS independent of effects on serum lipid levels.

MADD-FOLH1 Polymorphisms and Their Haplotypes with Serum Lipid Levels and the Risk of Coronary Heart Disease and Ischemic Stroke in a Chinese Han Population

This study aimed to detect the association of the MADD-FOLH1 single nucleotide polymorphisms (SNPs) and their haplotypes with the risk of coronary heart disease (CHD) and ischemic stroke (IS) in a Chinese Han population. Six SNPs of rs7395662, rs326214, rs326217, rs1051006, rs3736101, and rs7120118 were genotyped in 584 CHD and 555 IS patients, and 596 healthy controls. The genotypic and allelic frequencies of the rs7395662 SNP were different between controls and patients, and the genotypes of the rs7395662 SNP were associated with the risk of CHD and IS in different genetic models. Six main haplotypes among the rs1051006, rs326214, rs326217, rs3736101, and rs7120118 SNPs were detected in our study population, the haplotypes of G-G-T-G-C and G-A-T-G-T were associated with an increased risk of CHD and IS, respectively. The subjects with rs7395662GG genotype in controls had higher triglyceride (TG) and lower high-density lipoprotein cholesterol (HDL-C) levels than the subjects with AA/AG genotypes. Several SNPs interacted with alcohol consumption to influence serum TG (rs326214, rs326217, and rs7120118) and HDL-C (rs7395662) levels. The SNP of rs3736101 interacted with cigarette smoking to modify serum HDL-C levels. The SNP of rs1051006 interacted with body mass index ≥24 kg/m² to modulate serum low-density lipoprotein cholesterol levels. The interactions of several haplotypes and alcohol consumption on the risk of CHD and IS were also observed.

Intronic Polymorphisms in the CDKN2B-AS1 Gene Are Strongly Associated with the Risk of Myocardial Infarction and Coronary Artery Disease in the Saudi Population

Recent genome-wide association studies identified single nucleotide polymorphisms (SNPs) on the chromosome 9p21.3 conferring the risk for CAD (coronary artery disease) in individuals of Caucasian ancestry. We performed a genetic association study to investigate the effect of 12 candidate SNPs within 9p21.3 locus on the risk of CAD in the Saudi population of the Eastern Province of Saudi Arabia. A total of 250 Saudi CAD patients who had experienced an myocardial infarction (MI) and 252 Saudi age-matched healthy controls were genotyped using TaqMan assay. Controls with evidenced lack of CAD provided 90% of statistical power at the type I error rate of 0.05. Five percent of the results were rechecked for quality control using Sanger sequencing, the results of which concurred with the TaqMan genotyping results. Association analysis of 12 SNPs indicated a significant difference in the genotype distribution for four SNPs between cases and controls (rs564398 p = 0.0315, χ² = 4.6, odds ratio (OD) = 1.5; rs4977574 p = 0.0336, χ² = 4.5, OD = 1.4; rs2891168 p = 1.85 × 10 − 10, χ² = 40.6, OD = 2.1 and rs1333042 p = 5.14 × 10 − 9, χ² = 34.1, OD = 2.2). The study identified three protective haplotypes (TAAG p = 1.00 × 10 − 4; AGTA p = 0.022 and GGGCC p = 0.0175) and a risk haplotype (TGGA p = 2.86 × 10 − 10) for the development of CAD. This study is in line with others that indicated that the SNPs located in the intronic region of the CDKN2B-AS1 gene are associated with CAD.

SNP-SNP Interaction between TLR4 and MyD88 in Susceptibility to Coronary Artery Disease in the Chinese Han Population

The toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-dependent signaling pathway plays a role in the initiation and progression of coronary artery disease (CAD). We investigated SNP-SNP interactions between the TLR4 and MyD88 genes in CAD susceptibility and assessed whether the effects of such interactions were modified by confounding risk factors (hyperglycemia, hyperlipidemia and Helicobacter pylori (H. pylori) infection). Participants with CAD (n = 424) and controls (n = 424) without CAD were enrolled. Polymerase chain restriction-restriction fragment length polymorphism was performed on genomic DNA to detect polymorphisms in TLR4 (rs10116253, rs10983755, and rs11536889) and MyD88 (rs7744). H. pylori infections were evaluated by enzyme-linked immunosorbent assays, and the cardiovascular risk factors for each subject were evaluated clinically. The significant interaction between TLR4 rs11536889 and MyD88 rs7744 was associated with an increased CAD risk (p value for interaction = 0.024). In conditions of hyperglycemia, the interaction effect was strengthened between TLR4 rs11536889 and MyD88 rs7744 (p value for interaction = 0.004). In hyperlipidemic participants, the interaction strength was also enhanced for TLR4 rs11536889 and MyD88 rs7744 (p value for interaction = 0.006). Thus, the novel interaction between TLR4 rs11536889 and MyD88 rs7744 was related with an increased risk of CAD, that could be strengthened by the presence of hyperglycemia or hyperlipidemia.

Ion Channels and Oxidative Stress as a Potential Link for the Diagnosis or Treatment of Liver Diseases

Oxidative stress results from a disturbed balance between oxidation and antioxidant systems. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) may be either harmful or beneficial to the cells. Ion channels are transmembrane proteins that participate in a large variety of cellular functions and have been implicated in the development of a variety of diseases. A significant amount of the available drugs in the market targets ion channels. These proteins have sulfhydryl groups of cysteine and methionine residues in their structure that can be targeted by ROS and RNS altering channel function including gating and conducting properties, as well as the corresponding signaling pathways associated. The regulation of ion channels by ROS has been suggested to be associated with some pathological conditions including liver diseases. This review focuses on understanding the role and the potential association of ion channels and oxidative stress in liver diseases including fibrosis, alcoholic liver disease, and cancer. The potential association between ion channels and oxidative stress conditions could be used to develop new treatments for major liver diseases.