Simvastatin down-regulates osteogenic response in cultured human aortic valve interstitial cells

Risk score for coronary heart disease (CHD-RISK) and hemodynamically significant aortic valve stenosis

BACKGROUND AND AIM

Multiple studies have investigated the association between coronary heart disease (CHD) risk factors and aortic valve stenosis (AS). However, limited studies have explored the relationship between CHD risk scores and AS. Whether incident risk scores for coronary heart disease (CHD-RISK) may be applied to predict AS remains unclear. We aim to investigate the association between AS and CHD-RISK.

METHODS AND RESULTS

We included 4791 participants (age 54.6 ± 5.0 yrs, 58.7% women, 81% were of European origin), and CHD-RISK was estimated in 1990-1992. The participants were then followed-up until December 31, 2013. The primary outcome was hemodynamic significant AS identified by Doppler echocardiography in 2011-2013. We used multivariate-logistic regression models to assess the associations between CHD-RISK and AS. During follow-up, 963 (20.1%) cases of AS were identified. Per-standard deviation (6%) increase in CHD-RISK was associated with OR 95% Cl [1.194, 95% CI 1.068 to 1.335, p = 0.002] risk of AS in the fully adjusted models. Results were similar when stratified by quintiles of CHD-RISK, using the lowest quintiles <0.94% of CHD-RISK as the reference, 0.94%-2.26%, 2.26%-4.83%, 4.83%-9.21%, and >9.21% were; 1.33 (95% CI, 0.99-1.78, p = 0.055), 1.64 (95% CI, 1.17-2.29, p = 0.004), 2.23 (95% CI, 1.49-3.32, p = <0.001), 2.66 (95% CI, 1.65-4.31, p = <0.001) respectively.

CONCLUSIONS

CHD-RISK was associated with AS. CHD-RISK and AS were high in females, age ≥55 yrs, current smokers, and BMI ≥ 30 kg/m². This investigation suggests CHD-RISK may be applied to forecast AS risk similar to CHD. Future studies are required to detect, manage, and establish better treatment strategies in these high-risk subgroups.

MyD88: At the heart of inflammatory signaling and cardiovascular disease

Cardiovascular disease is a leading cause of death worldwide and is associated with systemic inflammation. In depth study of the cell-specific signaling mechanisms mediating the inflammatory response is vital to improving anti-inflammatory therapies that reduce mortality and morbidity. Cellular damage in the cardiovascular system results in the release of damage associated molecular patterns (DAMPs), also known as "alarmins," which activate myeloid cells through the adaptor protein myeloid differentiation primary response 88 (MyD88). MyD88 is broadly expressed in most cell types of the immune and cardiovascular systems, and its role often differs in a cardiovascular disease context and cell specific manner. Herein we review what is known about MyD88 in the setting of a variety of cardiovascular diseases, discussing cell specific functions and the relative contributions of MyD88-dependent vs. independent alarmin triggered inflammatory signaling. The widespread involvement of these pathways in cardiovascular disease, and their largely unexplored complexity, sets the stage for future in depth mechanistic studies that may place MyD88 in both immune and non-immune cell types as an attractive target for therapeutic intervention in cardiovascular disease.

Immunohistochemical Detection of Bacteria in the Resected Valves was Associated with Stromal Immune Checkpoint Protein Expression that may Contribute to Calcific Aortic Stenosis

Aortic stenosis (AS) is a disease characterized by narrowing of the aortic valve (AV) orifice. The purpose of this study was to clarify the significance of bacterial detection and clinicopathological factors, including valve-infiltrating immune cells and disease severity, in relation to AS. After obtaining the written informed consent form from 50 patients with AS, we performed immunohistochemical analysis of lipopolysaccharide (LPS) for gram-negative bacteria and lipoteichoic acid (LTA) for gram-positive bacteria on surgically resected-AVs. Moreover, we evaluated the relationships among the presence of bacteria, immune checkpoint protein PD-L1 expression, and immune cell infiltrations such as CD8-positive T lymphocytes, CD163-positive macrophages, and FOXP3-positive regulatory T cell (Treg) in resected-aortic valves. LPS detection in the resected-aortic valve tissues was significantly associated with stromal PD-L1 expression, valve calcification, and LTA existence in resected samples. We showed that the presence of LPS was significantly related to high PD-L1 expression only in calcified-AVs, not in non-calcified-AVs. Moreover, the high expression of PD-L1 in AS samples without LPS was significantly associated with positive infiltration of CD163-positive macrophages and FOXP3-positive Tregs. Immunohistochemical bacterial detection in resected-aortic valves was associated with PD-L1 accumulation and valve calcification. PD-L1 significantly accumulated only in calcified valves with LPS existence.

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.

Current Evidence and Future Perspectives on Pharmacological Treatment of Calcific Aortic Valve Stenosis

Calcific aortic valve stenosis (CAVS), the most common heart valve disease, is characterized by the slow progressive fibro-calcific remodeling of the valve leaflets, leading to progressive obstruction to the blood flow. CAVS is an increasing health care burden and the development of an effective medical treatment is a major medical need. To date, no effective pharmacological therapies have proven to halt or delay its progression to the severe symptomatic stage and aortic valve replacement represents the only available option to improve clinical outcomes and to increase survival. In the present report, the current knowledge and latest advances in the medical management of patients with CAVS are summarized, placing emphasis on lipid-lowering agents, vasoactive drugs, and anti-calcific treatments. In addition, novel potential therapeutic targets recently identified and currently under investigation are reported.

The Histone Demethylase KDM3B Promotes Osteo-/Odontogenic Differentiation, Cell Proliferation, and Migration Potential of Stem Cells from the Apical Papilla

Understanding the regulation mechanisms of mesenchymal stem cells (MSCs) can assist in tissue regeneration. The histone demethylase (KDM) family has a crucial role in differentiation and cell proliferation of MSCs, while the function of KDM3B in MSCs is not well understood. In this study, we used the stem cells from the apical papilla (SCAPs) to test whether KDM3B could regulate the function of MSCs. By an alkaline phosphatase (ALP) activity assay, Alizarin red staining, real-time RT-PCR, and western blot analysis, we found that KDM3B enhanced the ALP activity and mineralization of SCAPs and promoted the expression of runt-related transcription factor 2 (RUNX2), osterix (OSX), dentin sialophosphoprotein (DSPP), and osteocalcin (OCN). Additionally, the CFSE, CCK-8, and flow cytometry assays revealed that KDM3B improved cell proliferation by accelerating cell cycle transition from the G1 to S phase. Scratch and transwell migration assays displayed that KDM3B promoted the migration potential of SCAPs. Mechanically, microarray results displayed that 98 genes were upregulated, including STAT1, CCND1, and FGF5, and 48 genes were downregulated after KDM3B overexpression. Besides, we found that the Toll-like receptor and JAK-STAT signaling pathway may be involved in the regulating function of KDM3B in SCAPs. In brief, we discovered that KDM3B promoted the osteo-/odontogenic differentiation, cell proliferation, and migration potential of SCAPs and provided a novel target and theoretical basis for regenerative medicine.

A novel role of FKN/CX3CR1 in promoting osteogenic transformation of VSMCs and atherosclerotic calcification

Fractalkine (FKN) and its specific receptor CX3CR1 play a critical role in the pathogenesis of atherosclerosis including recruitment of vascular cells and the development of inflammation. However, its contribution to regulating the development of atherosclerotic calcification has not been well documented. Osteogenic transformation of vascular smooth muscle cells (VSMCs) is critical in the development of calcification in atherosclerotic lesions. In this study, for the first time, we evaluated the effect of FKN/CX3CR1 on the progression of VSMCs calcification and defined molecular signaling that is operative in the FKN/CX3CR1-induced osteogenic transformation of VSMCs. We found that high-fat diet induced atherosclerotic calcification in vivo was markedly inhibited in the Apolipoprotein E (ApoE) and CX3CR1 deficient (ApoE^-/-/CX3CR1^-/-) mice compared with their control littermates. FKN and CX3CR1 were both expressed in VSMCs and up-regulated by oxidized low-density lipoprotein (ox-LDL). FKN/CX3CR1 promoted the expression of osteogenic markers, including osteopontin (OPN), bone morphogenetic protein (BMP)-2 and alkaline phosphatase (ALP) and decreased VSMCs markers, including smooth muscle (SM) α-actin and SM22-α in a dose-dependent manner. The essential role of FKN/CX3CR1 in VSMCs calcification was further confirmed by lentivirus-mediated knockdown or overexpression of CX3CR1 blocked or accelerated osteogenic transformation of VSMCs. This response was associated with reciprocal up- and down-regulation of osteogenic factor, runt-related transcription factor 2 (RUNX2), transcription factors in osteoclast differentiation, receptor activator of nuclear factor-κB (RANK), RANK ligand (RNAKL) and osteoprotegerin (OPG), respectively. Inhibition of FKN/CX3CR1-activated Jak2/Stat3 signaling by the Jak/Stat inhibitor AG490 blocked osteogenic transformation of VSMCs and RUNX2 induction concurrently. Taken together, our data uncovered novel roles of FKN/CX3CR1 in promoting VSMC osteogenic transformation and atherosclerotic calcification by activating RUNX2 through Jak2/Stat3 signaling pathway and suppressing OPG. Our findings suggest that targeting FKN/CX3CR1 may provide new strategies for the prevention and treatment of atherosclerotic calcification.