Pathophysiology of valvular heart disease

Transcatheter Structural Heart Interventions in the Acute Setting: An Emerging Indication

Structural heart disease is increasingly prevalent in the general population, especially in patients of increased age. Recent advances in transcatheter structural heart interventions have gained a significant following and are now considered a mainstay option for managing stable valvular disease. However, the concept of transcatheter interventions has also been tested in acute settings by several investigators, especially in cases where valvular disease comes as a result of acute ischemia or in the context of acute decompensated heart failure. Tested interventions include both the mitral and aortic valve, mostly evaluating mitral transcatheter edge-to-edge repair and transcatheter aortic valve implantation, respectively. This review is going to focus on the use of acute structural heart interventions in the emergent setting, and it will delineate the available data and provide a meaningful discussion on the optimal patient phenotype and future directions of the field.

A study protocol to characterise pathophysiological and molecular markers of rheumatic heart disease and degenerative aortic stenosis using multiparametric cardiovascular imaging and multiomics techniques

INTRODUCTION

Rheumatic heart disease (RHD), degenerative aortic stenosis (AS), and congenital valve diseases are prevalent in sub-Saharan Africa. Many knowledge gaps remain in understanding disease mechanisms, stratifying phenotypes, and prognostication. Therefore, we aimed to characterise patients through clinical profiling, imaging, histology, and molecular biomarkers to improve our understanding of the pathophysiology, diagnosis, and prognosis of RHD and AS.

METHODS

In this cross-sectional, case-controlled study, we plan to recruit RHD and AS patients and compare them to matched controls. Living participants will undergo clinical assessment, echocardiography, CMR and blood sampling for circulatory biomarker analyses. Tissue samples will be obtained from patients undergoing valve replacement, while healthy tissues will be obtained from cadavers. Immunohistology, proteomics, metabolomics, and transcriptome analyses will be used to analyse circulatory- and tissue-specific biomarkers. Univariate and multivariate statistical analyses will be used for hypothesis testing and identification of important biomarkers. In summary, this study aims to delineate the pathophysiology of RHD and degenerative AS using multiparametric CMR imaging. In addition to discover novel biomarkers and explore the pathomechanisms associated with RHD and AS through high-throughput profiling of the tissue and blood proteome and metabolome and provide a proof of concept of the suitability of using cadaveric tissues as controls for cardiovascular disease studies.

A systematic review and meta-analysis on outcomes of valvular heart surgery in Africa

INTRODUCTION

The prevalence of valvular heart diseases remain considerably high in Africa, largely but not solely due to rheumatic heart disease. Valvular heart surgeries have emerged as the cornerstone in their management. While several studies have reported data on outcomes following heart valve surgery in many developed countries, there is a staggering paucity of data and evidence reporting the outcomes in the Africa population. The aim of this study is to report the perioperative outcomes following valvular heart surgery in Africa.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analysis guideline was utilized. Electronic searches were performed using PubMed, African journal online, and Research gate from inception to June 2023. The primary endpoints were overall mortality and 30-day mortality, and secondary endpoints included postoperative complications, length of hospital, and intensive care stays. The outcome data were pooled together and analyzed with the random effect model for proportions and mean for meta-analysis using the R software.

RESULTS

This systematic review identified 31 studies that fulfilled the study eligibility criteria and all were observational studies. The countries in which these studies were carried out include South Africa, Ethiopia, Egypt, Mali, Rwanda, Nigeria, Cameroon, Ghana, Senegal, Tanzania, and Kenya. Statistical analysis reported a pooled overall mortality of 10.48% and a pooled 30-day mortality of 4.59%.

CONCLUSION

Several obstacles, such as lack of financial resources and inadequate infrastructure, continue to impede valvular heart surgery practice in many parts of Africa. Future studies need to focus on identifying factors associated with this poor early mortality.

Exosomal Cargo: Pro-angiogeneic, anti-inflammatory, and regenerative effects in ischemic and non-ischemic heart diseases - A comprehensive review

Heart diseases are the primary cause of mortality and morbidity worldwide which inflict a heavy social and economic burden. Among heart diseases, most deaths are due to myocardial infarction (MI) or heart attack, which occurs when a decrement in blood flow to the heart causes injury to cardiac tissue. Despite several available diagnostic, therapeutic, and prognostic approaches, heart disease remains a significant concern. Exosomes are a kind of small extracellular vesicles released by different types of cells that play a part in intercellular communication by transferring bioactive molecules important in regenerative medicine. Many studies have reported the diagnostic, therapeutic, and prognostic role of exosomes in various heart diseases. Herein, we reviewed the roles of exosomes as new emerging agents in various types of heart diseases, including ischemic heart disease, cardiomyopathy, arrhythmia, and valvular disease, focusing on pathogenesis, therapeutic, diagnostic, and prognostic roles in different areas. We have also mentioned different routes of exosome delivery to target tissues, the effects of preconditioning and modification on exosome's capability, exosome production in compliance with good manufacturing practice (GMP), and their ongoing clinical applications in various medical contexts to shed light on possible clinical translation.

Artificial Intelligence-Based Prediction of Cardiovascular Diseases from Chest Radiography

Chest radiography (CXR) is the most frequently performed radiological test worldwide because of its wide availability, non-invasive nature, and low cost. The ability of CXR to diagnose cardiovascular diseases, give insight into cardiac function, and predict cardiovascular events is often underutilized, not clearly understood, and affected by inter- and intra-observer variability. Therefore, more sophisticated tests are generally needed to assess cardiovascular diseases. Considering the sustained increase in the incidence of cardiovascular diseases, it is critical to find accessible, fast, and reproducible tests to help diagnose these frequent conditions. The expanded focus on the application of artificial intelligence (AI) with respect to diagnostic cardiovascular imaging has also been applied to CXR, with several publications suggesting that AI models can be trained to detect cardiovascular conditions by identifying features in the CXR. Multiple models have been developed to predict mortality, cardiovascular morphology and function, coronary artery disease, valvular heart diseases, aortic diseases, arrhythmias, pulmonary hypertension, and heart failure. The available evidence demonstrates that the use of AI-based tools applied to CXR for the diagnosis of cardiovascular conditions and prognostication has the potential to transform clinical care. AI-analyzed CXRs could be utilized in the future as a complimentary, easy-to-apply technology to improve diagnosis and risk stratification for cardiovascular diseases. Such advances will likely help better target more advanced investigations, which may reduce the burden of testing in some cases, as well as better identify higher-risk patients who would benefit from earlier, dedicated, and comprehensive cardiovascular evaluation.

Etiologies and Patterns of Valvular Heart Disease Among Cardiac Patients at the Cardiac Center of Ethiopia During February 2000 to April 2022

Background

The leading global contributor to cardiovascular morbidity and mortality is valvular heart disease. It is on the rise worldwide, including in the developing countries. However, the prevalence, patterns, and etiologies of valvular heart disease have not been well studied in Ethiopia. Hence, the purpose of this study was to evaluate the prevalence, patterns, and etiologies of valvular heart disease at the Cardiac Center of Ethiopia from February 2000 to April 2022.

Methods

This institution-based retrospective cross-sectional study was conducted between February 2000 and April 2022. Data from three thousand two hundred fifty-seven VHD were extracted from the electronic medical records and analyzed using SPSS version 25. Descriptive statistics, such as the frequency, mean ± standard deviation, and cross tabulations, were used to summarize the data.

Results

Of 10,588 total cardiac cases registered and treated at the Cardiac Centre of Ethiopia from February 2000 to April 2022, 30.8% (3257) were diagnosed with VHD. The most typical diagnosis for VHD was multi-valvular involvement, which accounted for 49.5% of cases (1612), followed by pulmonary stenosis (15%) and mitral regurgitation (14.3%). Females were more likely to develop valve diseases than males, being at the highest risk for each identified etiology of valve disease 1928 (59.2%). The majority percentages of the population affected by VHD were between 18 and 44 age category 1473 (45.2%). The most common etiology of VHD was rheumatic 2015 (61.87%), followed by congenital origin 828 (25.42%).

Conclusion

VHD affects nearly one-third of all cardiac cases admitted to the hospital. Multi-valvular involvement is the most commonly diagnosed form of VHD. Rheumatic causes were more prevalent in this study. As found in this study, VHD affects a significant percentage of the population, which in turn could have an impact on the country's economy and deserve attention as a possible means of intervention.

The potential therapeutic impacts of trehalose on cardiovascular diseases as the environmental-influenced disorders: An overview of contemporary findings

Cardiovascular diseases (CVDs) as environmental-influenced disorders, are a major concern and the leading cause of death worldwide. A range of therapeutic approaches has been proposed, including conventional and novel methods. Natural compounds offer a promising alternative for CVD treatment due to their ability to regulate molecular pathways with minimal adverse effects. Trehalose is natural compound and disaccharide with unique biological functions and cardio-protective properties. The cardio-protective effects of trehalose are generated through its ability to induce autophagy, which is mediated by the transcription factors TFEB and FOXO1. The stimulation of TFEB plays a significant role in regulating autophagy genes and autophagosome formation. Activation of FOXO1 through dephosphorylation of Foxo1 and blocking of p38 mitogen-activated protein kinase (p38 MAPK) also triggers autophagy dramatically. Trehalose has been shown to reduce CVD risk factors, including atherosclerosis, cardiac remodeling after a heart attack, cardiac dysfunction, high blood pressure, and stroke. It also reduces structural abnormalities of mitochondria, cytokine production, vascular inflammation, cardiomyocyte apoptosis, and pyroptosis. This review provides a molecular overview of trehalose's cardioprotective functions, including its mechanisms of autophagy and its potential to improve CVD symptoms based on clinical evidence.

Organ-on-a-chip: Its use in cardiovascular research

Organ-on-a-chip (OOAC) has attracted great attention during the last decade as a revolutionary alternative to conventional animal models. This cutting-edge technology has also brought constructive changes to the field of cardiovascular research. The cardiovascular system, especially the heart as a well-protected vital organ, is virtually impossible to replicate in vitro with conventional approaches. This made scientists assume that they needed to use animal models for cardiovascular research. However, the frequent failure of animal models to correctly reflect the native cardiovascular system necessitated a search for alternative platforms for preclinical studies. Hence, as a promising alternative to conventional animal models, OOAC technology is being actively developed and tested in a wide range of biomedical fields, including cardiovascular research. Therefore, in this review, the current literature on the use of OOACs for cardiovascular research is presented with a focus on the basis for using OOACs, and what has been specifically achieved by using OOACs is also discussed. By providing an overview of the current status of OOACs in cardiovascular research and its future perspectives, we hope that this review can help to develop better and optimized research strategies for cardiovascular diseases (CVDs) as well as identify novel applications of OOACs in the near future.

A biomimetic multilayered polymeric material designed for heart valve repair and replacement

Materials currently used to repair or replace a heart valve are not durable. Their limited durability related to structural degeneration or thrombus formation is attributed to their inadequate mechanical properties and biocompatibility profiles. Our hypothesis is that a biostable material that mimics the structure, mechanical and biological properties of native tissue will improve the durability of these leaflets substitutes and in fine improve the patient outcome. Here, we report the development, optimization, and testing of a biomimetic, multilayered material (BMM), designed to replicate the native valve leaflets. Polycarbonate urethane and polycaprolactone have been processed as film, foam, and aligned fibers to replicate the leaflet's architecture and anisotropy, through solution casting, lyophilization, and electrospinning. Compared to the commercialized materials, our BMMs exhibited an anisotropic behavior and a closer mechanical performance to the aortic leaflets. The material exhibited superior biostability in an accelerated oxidization environment. It also displayed better resistance to protein adsorption and calcification in vitro and in vivo. These results will pave the way for a new class of advanced synthetic material with long-term durability for surgical valve repair or replacement.

Multimodal Treatment and Diagnostic Modalities in the Setting of Heyde’s Syndrome: A Systematic Review

Heyde’s syndrome encompasses the triad of aortic stenosis (AS), angiodysplasia, and acquired Von Willebrand's disease (aVWD). The disease itself is a rare association that affects a small subset of patients who suffer from aortic stenosis. Nonetheless, it represents a vital area of clinical interest and is woefully underreported in the literature. Patients with Heyde’s syndrome develop gastrointestinal bleeding (GI) as a result of angiodysplasia and due to lack of adequate hemostasis, they tend to be positively predisposed toward developing gastrointestinal hemorrhage. Due to the glaring lack of comprehensive literature on Heyde's syndrome, this systematic review aims to bridge the gap by elucidating the various diagnostic and treatment options available to clinicians for Heyde’s syndrome patients as well as to give a detailed account of the pathophysiology of the disease.

This systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Google Scholar, Gulf Medical University (GMU) e-library, and PubMed were thoroughly searched for studies done in the last 10 years, which corresponds with our outlined inclusion and exclusion criteria. Relevant studies were then selected on the basis of their abstracts and titles. These studies then underwent a comprehensive quality assessment in which any papers which did not meet this study’s eligibility criteria were omitted. Overall, 18 studies fulfilled the criteria of this systematic review.

Pathogenesis and Molecular Immune Mechanism of Calcified Aortic Valve Disease

Calcified aortic valve disease (CAVD) was previously regarded as a passive process associated with valve degeneration and calcium deposition. However, recent studies have shown that the occurrence of CAVD is an active process involving complex changes such as endothelial injury, chronic inflammation, matrix remodeling, and neovascularization. CAVD is the ectopic accumulation of calcium nodules on the surface of the aortic valve, which leads to aortic valve thickening, functional stenosis, and ultimately hemodynamic disorders. CAVD has become an important cause of death from cardiovascular disease. The discovery of therapeutic targets to delay or block the progression of CAVD and the clinical application of transcatheter aortic valve implantation (TAVI) provide new ideas for the prevention and treatment of CAVD. This article summarizes the pathogenesis of CAVD and provides insight into the future directions of CAVD diagnosis and treatment.

Aortic valve cell microenvironment: Considerations for developing a valve-on-chip

Cardiac valves are sophisticated, dynamic structures residing in a complex mechanical and hemodynamic environment. Cardiac valve disease is an active and progressive disease resulting in severe socioeconomic burden, especially in the elderly. Valve disease also leads to a 50% increase in the possibility of associated cardiovascular events. Yet, valve replacement remains the standard of treatment with early detection, mitigation, and alternate therapeutic strategies still lacking. Effective study models are required to further elucidate disease mechanisms and diagnostic and therapeutic strategies. Organ-on-chip models offer a unique and powerful environment that incorporates the ease and reproducibility of in vitro systems along with the complexity and physiological recapitulation of the in vivo system. The key to developing effective valve-on-chip models is maintaining the cell and tissue-level microenvironment relevant to the study application. This review outlines the various components and factors that comprise and/or affect the cell microenvironment that ought to be considered while constructing a valve-on-chip model. This review also dives into the advancements made toward constructing valve-on-chip models with a specific focus on the aortic valve, that is, in vitro studies incorporating three-dimensional co-culture models that incorporate relevant extracellular matrices and mechanical and hemodynamic cues.

Comparison of Serotonin-Regulated Calcific Processes in Aortic and Mitral Valvular Interstitial Cells

Calcification is an important pathological process and a common complication of degenerative valvular heart diseases, with higher incidence in aortic versus mitral valves. Two phenotypes of valvular interstitial cells (VICs), activated VICs and osteoblastic VICs (obVICs), synergistically orchestrate this pathology. It has been demonstrated that serotonin is involved in early stages of myxomatous mitral degeneration, whereas the role of serotonin in calcific aortic valve disease is still unknown. To uncover the link between serotonin and osteogenesis in heart valves, osteogenesis of aortic and mitral VICs was induced in vitro. Actin polymerization and serotonin signaling were inhibited using cytochalasin D and serotonin inhibitors, respectively, to investigate the role of cell activation and serotonin signals in valvular cell osteogenesis. To evaluate calcification progress, calcium and collagen deposits along with the expression of protein markers, including the rate-limiting enzyme of serotonin synthesis [tryptophan hydroxylase 1 (TPH1)], were assessed. When exposed to osteogenic culture conditions and grown on soft surfaces, passage zero aortic VICs increased extracellular collagen deposits and obVIC phenotype markers. A more intense osteogenic process was observed in aortic VICs of higher passages, where cells were activated prior to osteogenic induction. For both, TPH1 expression was upregulated as osteogenesis advanced. However, these osteogenic changes were reversed upon serotonin inhibition. This discovery provides a better understanding of signaling pathways regulating VIC phenotype transformation and explains different manifestations of degenerative pathologies. In addition, the discovery of serotonin-based inhibition of valvular calcification will contribute to the development of potential novel therapies for calcific valvular diseases.

Convolutional and recurrent neural networks for the detection of valvular heart diseases in phonocardiogram recordings

Valvular heart diseases (VHD) are one of the major causes of cardiovascular diseases that are having high mortality rates worldwide. The early diagnosis of VHD prevents the development of cardiac diseases and allows for optimum medication. Despite of the ability of current gold standards in identifying VHD, they still lack the required accuracy and thus, several cases go misdiagnosed. In this vein, a study is conducted herein to investigate the efficiency of deep learning models in identifying VHD through phonocardiography (PCG) recordings. PCG heart sounds were obtained from an open-access data-set representing normal heart sounds along with four major VHD; namely aortic stenosis (AS), mitral stenosis (MS), mitral regurgitation (MR), and mitral valve prolapse (MVP). A total of 1,000 patients were involved in the study with 200 recordings for each class. All recordings were initially trimmed to have 9,600 samples ensuring their coverage of at least 1 cardiac cycle. In addition, they were pre-processed by applying maximal overlap discrete wavelet transform (MODWT) smoothing algorithm and z-score normalization. The neural network architecture was designed to reduce the complexity often found in literature and consisted of a combination of convolutional neural networks (CNN) and recurrent neural networks (RNN) based on Bi-directional long short-term memory (BiLSTM). The model was trained and tested following a k-fold cross-validation scheme of 10-folds utilizing the CNN-BiLSTM network as well as the CNN and BiLSTM, individually. The highest performance was achieved using the CNN-BiLSTM network with an overall Cohen's kappa, accuracy, sensitivity, and specificity of 97.87%, 99.32%, 98.30%, and 99.58%, respectively. In addition, the model had an average area under the curve (AUC) of 0.998. Furthermore, the performance of the model was assessed on the PhysioNet/Computing in Cardiology 2016 challenge data-set and reached an overall accuracy of 87.31% with an AUC of 0.900. This study paves the way towards implementing deep learning models in VHD identification under clinical settings to assist clinicians in decision making and prevent many cases from cardiac abnormalities development.

Evaluation of epicardial fat thickness and the ankle-brachial index in patients with rosacea: A case-control study

BACKGROUND

Recent data suggest that rosacea is related to cardiovascular diseases (CVD) due to its inflammatory nature and immune dysregulation.

AIM

The aim of this study was to evaluate the values of epicardial fat thickness (EFT) and the ankle-brachial index (ABI) in patients with rosacea, as indicators of subclinical atherosclerosis and CVD risk.

METHODS

This prospective case-control study was carried out on 62 participants, including 31 rosacea patients and 31 controls. The values of EFT and ABI were measured in all subjects.

RESULTS

The mean thickness of EFT was statistically higher in rosacea patients (0.54 ± 0.12 mm) than in the controls (0.39 ± 0.05 mm) (P < 0.01). ABI was not significantly different between the subjects with rosacea and the comparison group (1.02 ± 0.1 vs 0.98 ± 0.07; P = 0.131). A total of 29% of the rosacea patients had mitral valve insufficiency (MVI), while 3.2% of the control group had MVI (P = 0.006). A mild degree of tricuspid valve insufficiency (TVI) was present in 45.2% of the rosacea patients, while 19.4% of the controls had TVI (P = 0.03).

CONCLUSION

Rosacea may be associated with subclinical cardiac dysfunction. EFT measurements in rosacea patients can provide early detection of possible subclinical cardiovascular diseases, which can be life-extending in rosacea. However, further studies with larger sample sizes are required to confirm the present findings.

An update on vascular calcification and potential therapeutics

Pathological calcification is a major cause of cardiovascular morbidities primarily in population with chronic kidney disease (CKD), end stage renal diseases (ERSD) and metabolic disorders. Investigators have accepted the fact that vascular calcification is not a passive process but a highly complex, cell mediated, active process in patients with cardiovascular disease (CVD) resulting from, metabolic insults of bone fragility, diabetes, hypertension, dyslipidemia and atherosclerosis. Over the years, studies have revealed various mechanisms of vascular calcification like induction of bone formation, apoptosis, alteration in Ca-P balance and loss of inhibition. Novel clinical studies targeting cellular mechanisms of calcification provide promising and potential avenues for drug development. The interventions include phosphate binders, sodium thiosulphate, vitamin K, calcimimetics, vitamin D, bisphosphonates, Myoinositol hexaphosphate (IP6), Denosumab and TNAP inhibitors. Concurrently investigators are also working towards reversing or curing pathological calcification. This review focuses on the relationship of vascular calcification to clinical diseases, regulators and factors causing calcification including genetics which have been identified. At present, there is lack of any significant preventive measures for calcifications and hence this review explores further possibilities for drug development and treatment modalities.

Inappropriate cathepsin K secretion promotes its enzymatic activation driving heart and valve malformation

Although congenital heart defects (CHDs) represent the most common birth defect, a comprehensive understanding of disease etiology remains unknown. This is further complicated since CHDs can occur in isolation or as a feature of another disorder. Analyzing disorders with associated CHDs provides a powerful platform to identify primary pathogenic mechanisms driving disease. Aberrant localization and expression of cathepsin proteases can perpetuate later-stage heart diseases, but their contribution toward CHDs is unclear. To investigate the contribution of cathepsins during cardiovascular development and congenital disease, we analyzed the pathogenesis of cardiac defects in zebrafish models of the lysosomal storage disorder mucolipidosis II (MLII). MLII is caused by mutations in the GlcNAc-1-phosphotransferase enzyme (Gnptab) that disrupt carbohydrate-dependent sorting of lysosomal enzymes. Without Gnptab, lysosomal hydrolases, including cathepsin proteases, are inappropriately secreted. Analyses of heart development in gnptab-deficient zebrafish show cathepsin K secretion increases its activity, disrupts TGF-β–related signaling, and alters myocardial and valvular formation. Importantly, cathepsin K inhibition restored normal heart and valve development in MLII embryos. Collectively, these data identify mislocalized cathepsin K as an initiator of cardiac disease in this lysosomal disorder and establish cathepsin inhibition as a viable therapeutic strategy.

Mislocalized cathepsin K promotes cardiac disease in a zebrafish model of the lysosomal disorder mucolipidosis II and can be targeted by cathespin inhibition.

Preoperative myocardial expression of E3 ubiquitin ligases in aortic stenosis patients undergoing valve replacement and their association to postoperative hypertrophy

Currently, aortic valve replacement is the only treatment capable of relieving left ventricle pressure overload in patients with severe aortic stenosis. It aims to improve cardiac function and revert hypertrophy, by triggering myocardial reverse remodeling. Despite immediately relieving afterload, reverse remodeling turns out to be extremely variable. Among other factors, the extent of reverse remodeling may depend on how well ubiquitin-proteasome system tackle hypertrophy. Therefore, we assessed tagged ubiquitin and ubiquitin ligases in the left ventricle collected from patients undergoing valve replacement and tested their association to the degree of reverse remodeling. Patients were classified according to the regression of left ventricle mass (ΔLVM) and assigned to complete (ΔLVM≥15%) or incomplete (ΔLVM≤5%) reverse remodeling groups. No direct inter-group differences were observed. Nevertheless, correlation analysis supports a fundamental role of the ubiquitin-proteasome system during reverse remodeling. Indeed, total protein ubiquitination was associated to hypertrophic indexes such as interventricular septal thickness (r = 0.55, p = 0.03) and posterior wall thickness (r = 0.65, p = 0.009). No significant correlations were observed for Muscle Ring Finger 3. Surprisingly, though, higher levels of atrogin-1 were associated to postoperative interventricular septal thickness (r = 0.71, p = 0.005). In turn, Muscle Ring Finger 1 correlated negatively with this postoperative hypertrophy marker (r = -0.68, p = 0.005), suggesting a cardioprotective role during reverse remodeling. No significant correlations were found with left ventricle mass regression, although a trend for a negative association between the ligase Murine Double Minute 2 and mass regression (r = -0.44, p = 0.10) was found. Animal studies will be necessary to understand whether this ligase is protective or detrimental. Herein, we show, for the first time, an association between the preoperative myocardial levels of ubiquitin ligases and postoperative hypertrophy, highlighting the therapeutic potential of targeting ubiquitin ligases in incomplete reverse remodeling.

Vascular Calcification-New Insights Into Its Mechanism

Vascular calcification (VC), which is categorized by intimal and medial calcification, depending on the site(s) involved within the vessel, is closely related to cardiovascular disease. Specifically, medial calcification is prevalent in certain medical situations, including chronic kidney disease and diabetes. The past few decades have seen extensive research into VC, revealing that the mechanism of VC is not merely a consequence of a high-phosphorous and -calcium milieu, but also occurs via delicate and well-organized biologic processes, including an imbalance between osteochondrogenic signaling and anticalcific events. In addition to traditionally established osteogenic signaling, dysfunctional calcium homeostasis is prerequisite in the development of VC. Moreover, loss of defensive mechanisms, by microorganelle dysfunction, including hyper-fragmented mitochondria, mitochondrial oxidative stress, defective autophagy or mitophagy, and endoplasmic reticulum (ER) stress, may all contribute to VC. To facilitate the understanding of vascular calcification, across any number of bioscientific disciplines, we provide this review of a detailed updated molecular mechanism of VC. This encompasses a vascular smooth muscle phenotypic of osteogenic differentiation, and multiple signaling pathways of VC induction, including the roles of inflammation and cellular microorganelle genesis.

Non-coding RNAs: Regulators of valvular calcification

There is currently a growing global burden of valvular heart diseases due to aging populations and changing lifestyles. Valvular heart diseases mainly include the malfunctioning of aortic and mitral valves and are characterized by extensive tissue remodeling, which includes calcification, endothelial dysfunction, and endothelial-mesenchymal transition. These valvular remodeling processes are known to be regulated by protein-coding genes as well as non-coding genes. Here, we have summarized studies highlighting the non-coding RNA mediated regulation of valvular tissue remodeling and their potential therapeutic benefits. Additionally, studies investigating the diagnostic capability of circulating non-coding RNA molecules in valvular diseases are also summarized. Overall, of the various candidates, several studies have highlighted miR-214 and miR-204 as central regulators of valvular calcification.

Elastin-Dependent Aortic Heart Valve Leaflet Curvature Changes During Cyclic Flexure

The progression of calcific aortic valve disease (CAVD) is characterized by extracellular matrix (ECM) remodeling, leading to structural abnormalities and improper valve function. The focus of the present study was to relate aortic valve leaflet axial curvature changes as a function of elastin degradation, which has been associated with CAVD. Circumferential rectangular strips (L × W = 10 × 2.5 mm) of normal and elastin-degraded (via enzymatic digestion) porcine AV leaflets were subjected to cyclic flexure (1 Hz). A significant increase in mean curvature (p < 0.05) was found in elastin-degraded leaflet specimens in comparison to un-degraded controls at both the semi-constrained (50% of maximum flexed state during specimen bending and straightening events) and fully-constrained (maximally-flexed) states. This significance did not occur in all three flexed configurations when measurements were performed using either minimum or maximum curvature. Moreover, the mean curvature increase in the elastin-degraded leaflets was most pronounced at the instance of maximum flexure, compared to un-degraded controls. We conclude that the mean axial curvature metric can detect distinct spatial changes in aortic valve ECM arising from the loss in bulk content and/or structure of elastin, particularly when there is a high degree of tissue bending. Therefore, the instance of maximum leaflet flexure during the cardiac cycle could be targeted for mean curvature measurements and serve as a potential biomarker for elastin degradation in early CAVD remodeling.

Mitochondrial DNA haplogroups influence the risk of aortic stenosis

AIM

The underlying pathophysiologic mechanisms of aortic stenosis are not clear. Mitochondrial dysfunction plays a role in many pathological conditions including cardiac diseases. We aimed to analyze the mitochondrial DNA haplogroups in a group of patients undergoing valve replacement surgery due to severe aortic stenosis.

METHODS

Mitochondrial DNA haplogroups were assessed in 176 patients with severe aortic stenosis and 308 control subjects. Cardiovascular risk factors and demographics were similar in both groups.

RESULTS

Patients carrying haplogroup Uk had a lower risk of developing aortic stenosis, especially compared to patients carrying haplogroup H (odds ratio = 0.507; 95% confidence interval: 0.270-0.952, p = 0.035).

CONCLUSIONS

Mitochondrial DNA haplogroups could be involved in the development of severe aortic stenosis. Specifically, haplogroup H could be a risk factor and Uk a protective factor for severe aortic stenosis in a population from Spain.

Serotonin and catecholamines in the development and progression of heart valve diseases

Heart valve diseases (HVDs) arise from a number of different processes that affect both the structure and function of the valve apparatus. Despite diverse aetiologies, treatments for HVDs are limited to percutaneous or surgical interventions. The search for medical therapies to prevent or slow the progression of HVDs has been hampered by our poor understanding of the progression from subclinical to symptomatic phases, and our limited knowledge of the molecular signals that control the susceptibility of valve interstitial cells to pathological remodeling. Clinical evidence has suggested a link between certain neurotransmitters and valvular diseases of the heart. The fenfluramine-phentermine appetite suppressants popular in the 1980s were linked to mitral valve dysfunction, and ergot-derived dopamine agonists for Parkinson's disease have been associated with an increased risk of mitral and aortic valve regurgitation. The effect does not appear to be limited to medications, as valvular pathologies have also been observed in patients with carcinoid tumours of serotonin-producing enterochromaffin cells. The role of neurotransmitter molecules in valve pathology has not been adequately characterized and may represent a target for future medical therapies. Here we present current evidence from both clinical and basic science suggesting a link between neurotransmitters and HVDs, opening the door to future research in this area.

Asymptomatic heart valve dysfunction in healthy middle-aged companion dogs and its implications for cardiac aging

Heart disease is the leading cause of death in the USA, accounting for about one in every four deaths. Age is the greatest risk factor for heart disease in both people and dogs; however, heart disease is generally not considered as a major cause of morbidity or mortality in dogs. As part of the preliminary selection process for a veterinary clinical trial, 40 companion dogs with no history of cardiac pathology that were at least 6 years old and weighed at least 18 kg underwent a cardiac screening using Doppler echocardiography. Eleven dogs from this cohort were diagnosed with valvular regurgitation by echocardiography, and seven of these cases were of sufficient severity to warrant exclusion from the clinical trial. In only one case was a heart murmur detected by auscultation. Serum alkaline phosphatase levels were significantly higher in the dogs with moderate to severe valvular regurgitation compared to the rest of the cohort. These observations suggest that asymptomatic degenerative valvular disease detectable by echocardiography, but not by a standard veterinary exam including auscultation, may be present in a significant fraction of middle-aged companion dogs, indicating a previously underappreciated similarity between human and canine aging. Further, these data suggest that companion dogs may be a particularly useful animal model for understanding mechanisms of age-related degenerative valve disease and for developing and testing interventions to ameliorate cardiac disease. Future studies should address whether dogs with asymptomatic valve disease are at higher risk for subsequent morbidity or early death.

Concentrations of fetuin-A, osteoprotegerin and α-Klotho in patients with alcoholic liver cirrhosis

The aim of the present study was to evaluate the concentrations of fetuin-A, osteoprotegerin (OPG) and α-Klotho protein in patients with alcoholic cirrhosis at different stages of the disease, and to demonstrate that fetuin-A, osteoprotegin and α-Klotho may be used as markers of the severity of cirrhosis. A total of 54 patients with alcoholic liver cirrhosis treated in various hospitals in the Lublin region of Poland were randomly enrolled. The control group consisted of 18 healthy individuals without liver disease, who did not drink alcohol. Serum levels of fetuin-A, OPG and α-Klotho were measured by ELISA kits. Levels of fetuin-A were significantly reduced in patients with alcoholic liver cirrhosis compared with the control group. OPG levels were higher in patients with alcoholic liver cirrhosis than in the controls, whereas the levels of α-Klotho were comparable in the cirrhosis and control groups. No statistically significant differences in the concentrations of fetuin-A, OPG and α-Klotho protein were demonstrated according to type of liver cirrhosis. The findings of the present study revealed a significant negative correlation between the level of α-Klotho protein and C-reactive protein in the patients with alcoholic liver cirrhosis. Concentrations of fetuin-A were lower, whereas those of OPG were higher, in the alcoholic liver cirrhosis group compared with the control group. Fetuin-A, OPG and α-Klotho may not be good indicators of liver cirrhosis severity. In conclusion, fetuin-A and OPG may be used in the diagnosis of liver cirrhosis.

The mechanisms, diagnosis and management of mitral regurgitation in mitral valve prolapse and hypertrophic cardiomyopathy

Valvular disease is a frequent cardiac pathology leading to heart failure and, ultimately, death. Mitral regurgitation, defined as the inability of the two mitral leaflets to coapt, is a common valvular disease and a self sustained pathology. A better understanding of the mitral valve histological layers provides a better understanding of the leaflet and chordae changes in mitral valve prolapse. Mitral valve prolapse may occur in myxomatous degenerative abnormalities, connective tissue disorders or in sporadic isolated cases. It is the most common mitral abnormality of non-ischemic cause leading to severe surgery-requiring mitral regurgitation. In addition to standard echocardiographic investigations, newly implemented three-dimensional techniques are being used and they permit a better visualisation, from the so-called ‘surgical view’, and an improved evaluation of the mitral valve. Hypertrophic cardiomyopathy is the most frequent inherited myocardial disease caused by mutations in various genes encoding proteins of the cardiac sarcomere, leading to a marked left ventricular hypertrophy unexplained by other comorbidities. The pathological echocardiographic hallmarks of hypertrophic cardiomyopathy are left ventricular hypertrophy, left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve. The systolic anterior motion of the mitral valve contributes to the development of mitral regurgitation and further narrows the left ventricular outflow tract, leading to more severe symptomatology. Cardiac magnetic resonance imaging accurately measures the left ventricular mass, the degree of diastolic function and it may also be used to distinguish phenotypic variants. The clinical outcome of patients with these pathologies is mostly determined by the selected option of treatment. The purpose of surgical correction regarding mitral valve involvement is to restore valvular competence. Surgery has proven to be the only useful treatment in preventing heart failure, improving symptomatology and reducing mortality. Our approach wishes to enhance the understanding of the mitral valve’s involvement in hypertrophic cardiomyopathy and mitral valve prolapse from genetic, haemodynamic and clinical perspectives, as well as to present novelties in the grand field of treatment.