Aortic valve calcification in the era of non-coding RNAs: The revolution to come in aortic stenosis management?

Biomarkers as Prognostic Markers for Aortic Stenosis: A Review

Aortic stenosis (AS) is the most frequent valvular heart disease among the older individuals. Current guidelines indicate intervention for patients with symptomatic or fast progressive severe AS and asymptomatic patients with a reduced left ventricular (LV) ejection fraction by 50%. Interestingly, myocardial damage may have already happened by the time symptoms appear or LV function deteriorates. Serum biomarkers can be an early indicator to show LV function decline and AS progression even before clinical symptom onset. Studies have shown that cardiac biomarkers have prognostic value in patients with AS. Hence, cardiac biomarkers can be helpful in determining the optimum time to intervene. Transcatheter aortic valve replacement is a less invasive alternative to conventional surgical aortic valve replacement. The elevation of cardiac biomarkers at discharge has been associated with 2-year mortality after transcatheter aortic valve replacement. The correlation between biomarkers and AS-associated morbidity and mortality is an area to explore further. The authors of this review article have discussed the role of cardiac biomarkers in patients with AS for better risk stratification and identification of patients who would benefit from early intervention.

Neutrophil-Lymphocyte Ratio and Red Blood Cell Distribution Width in Patients with Atrial Fibrillation and Rheumatic Valve Disease

The lifetime risk of developing atrial fibrillation (AF) is 1 in 3 adults, resulting in a prevalence of 2-4%. Rheumatic heart disease (RHD) is a frequent aetiology of valvular heart disease in lowand middle-income countries. Between 21% and 80% of patients with mitral valve disease, especially with stenosis, may have AF. Both these conditions, AF and RHD, present a state of persistent inflammation. In turn, inflammation is a frequent cause of anisocytosis, which can be evidenced through the parameter RDW (red bold cell distribution width). Factors associated with increased RDW are also known as risk factors associated with a higher incidence of AF. RDW may have an independent role in the pathogenesis of AF and the increased propensity of both thromboembolic and bleeding events. Another marker involved in the incidence of AF is the neutrophil-lymphocyte ratio. This is also a marker of oxidative stress and inflammation and is associated with a higher rate of AF recurrence. This review will evaluate these biomarkers and their association with cardiovascular events in patients with AF and RHD. The hypotheses and current debates about the relationship of biomarkers with the severity of chronic valve dysfunction, with acute rheumatic carditis in the paediatric population, and with the presence of thrombus in the left atrium will be discussed.

miRNA in Ischemic Heart Disease and Its Potential as Biomarkers: A Comprehensive Review

Ischemic heart disease (IHD) constitutes the leading global cause of mortality and morbidity. Although significant progress has been achieved in the diagnosis, treatment, and prognosis of IHD, more robust diagnostic biomarkers and therapeutic interventions are still needed to circumvent the increasing incidence of IHD. MicroRNAs (miRNAs) are critical regulators of cardiovascular function and are involved in various facets of cardiovascular biology. While the knowledge of the role of miRNAs in IHD as diagnostic biomarkers has improved, research emphasis on how miRNAs can be effectively used for diagnosis and prognosis of IHD is crucial. This review provides an overview of the biology, therapeutic and diagnostic potential, as well as the caveats of using miRNAs in IHD based on existing research.

The mechanistic pathways of oxidative stress in aortic stenosis and clinical implications

Despite the elucidation of the pathways behind the development of aortic stenosis (AS), there remains no effective medical treatment to slow or reverse its progress. Instead, the gold standard of care in severe or symptomatic AS is replacement of the aortic valve. Oxidative stress is implicated, both directly as well as indirectly, in lipid infiltration, inflammation and fibro-calcification, all of which are key processes underlying the pathophysiology of degenerative AS. This culminates in the breakdown of the extracellular matrix, differentiation of the valvular interstitial cells into an osteogenic phenotype, and finally, calcium deposition as well as thickening of the aortic valve. Oxidative stress is thus a promising and potential therapeutic target for the treatment of AS. Several studies focusing on the mitigation of oxidative stress in the context of AS have shown some success in animal and in vitro models, however similar benefits have yet to be seen in clinical trials. Statin therapy, once thought to be the key to the treatment of AS, has yielded disappointing results, however newer lipid lowering therapies may hold some promise. Other potential therapies, such as manipulation of microRNAs, blockade of the renin-angiotensin-aldosterone system and the use of dipeptidylpeptidase-4 inhibitors will also be reviewed.

Aortic valve disease in diabetes: Molecular mechanisms and novel therapies

Valve disease and particularly calcific aortic valve disease (CAVD) and diabetes (DM) are progressive diseases constituting a global health burden for all aging societies (Progress in Cardiovascular Diseases. 2014;56(6):565: Circulation Research. 2021;128(9):1344). Compared to non‐diabetic individuals (The Lancet. 2008;371(9626):1800: The American Journal of Cardiology. 1983;51(3):403: Journal of the American College of Cardiology. 2017;69(12):1523), the diabetic patients have a significantly greater propensity for cardiovascular disorders and faster degeneration of implanted bioprosthetic aortic valves. Previously, using an original experimental model, the diabetic‐hyperlipemic hamsters, we have shown that the earliest alterations induced by these conditions occur at the level of the aortic valves and, with time these changes lead to calcifications and CAVD. However, there are no pharmacological treatments available to reverse or retard the progression of aortic valve disease in diabetes, despite the significant advances in the field. Therefore, it is critical to uncover the mechanisms of valve disease progression, find biomarkers for diagnosis and new targets for therapies. This review aims at presenting an update on the basic research in CAVD in the context of diabetes. We provide an insight into the accumulated data including our results on diabetes‐induced progressive cell and molecular alterations in the aortic valve, new potential biomarkers to assess the evolution and therapy of the disease, advancement in targeted nanotherapies, tissue engineering and the potential use of circulating endothelial progenitor cells in CAVD.

Telocytes-derived extracellular vesicles alleviate aortic valve calcification by carrying miR-30b

AIMS

Calcific aortic valve disease (CAVD) is frequent in the elderly. Telocytes (TCs) are implicated in intercellular communication by releasing extracellular vesicles (EVs). This study investigated the role of TC-EVs in aortic valve calcification.

METHODS AND RESULTS

TCs were obtained and identified using enzymolysis method and flow cytometry. EVs were isolated from TCs using differential high-speed centrifugation method and identified using transmission electron microscope, western blot, and qNano analysis. The mouse model of CAVD was established. The changes of aortic valve activity-related indicators were analysed by ultrasound, and the expressions of TC markers CD34 and vimentin in mouse valve tissues were detected using RT-qPCR and western blot. The model mice were injected with TC-derived EVs. The expressions of Runx2, osteocalcin, and caspase-3 were detected using RT-qPCR and western blot. The calcification model of valvular interstitial cells (VICs) was established. TC-EVs were co-cultured with calcified VICs, and calcium deposition was detected using alizarin red S staining. miR-30b expression in calcified valvular tissues and cells was detected after EV treatment. miR-30b expression in TCs was knocked down and then EVs were extracted and co-cultured with calcified VICs. The target of miR-30b was predicted through bioinformatics website and verified using dual-luciferase assay. The levels of Wnt/β-catenin pathway-related proteins were detected. ApoE^-/- mice fed with a high-fat diet showed decreased aortic valve orifice area, increased aortic transvalvular pressure difference and velocity, reduced left ventricular ejection fraction, decreased CD34 and vimentin, and increased caspase-3, Runx2, and osteocalcin. The levels of apoptosis- and osteogenesis- related proteins were inhibited after EV treatment. TC-EVs reduced calcium deposition and osteogenic proteins in calcified VICs. EVs could be absorbed by VICs. miR-30b expression was promoted in calcified valvular tissues and cells after EV treatment. Knockdown of miR-30b weakened the inhibitory effects of TC-EVs on calcium deposition and osteogenic proteins. miR-30b targeted Runx2. EV treatment inhibited the Wnt/β-catenin pathway, and knockdown of miR-30b in TCs attenuated the inhibitory effect of TC-EVs on the Wnt/β-catenin pathway.

CONCLUSION

TC-EVs played a protective role in aortic valve calcification via the miR-30b/Runx2/Wnt/β-catenin axis.