Long noncoding TSI attenuates aortic valve calcification by suppressing TGF-ß1-induced osteoblastic differentiation of valve interstitial cells.

INTRODUCTION: Calcific aortic valve disease (CAVD) is an active and cellular-driven fibrocalcific process characterised by differentiation of valve interstitial cells (VICs) towards an osteogenic-like phenotype. A recently identified lncRNA, lncTSI, has been reported to inhibit fibrogenesis through transforming growth factor (TGF)-ß/Smad3 pathway. Here, the present study aimed to investigate the role of lncTSI in CAVD. METHODS: The effect of TGF-ß1 on lncTSI of VICs was measured. TGF-ß1, RUNX2 and collagen I expression between calcified aortic valve tissue and normal samples by immunohistochemistry and western blotting. Human VICs were cultured and treated with TGF-ß1. SiRNA and pcDNA3.1-lncTSI plasmid transfection were used to silence and overexpress lncTSI in VICs for 48 h, Smads phosphorylation, RUNX2 and collagen I expression were then verified by western blotting. In ApoE-/- mice fed with 0.25 % high-cholesterol diet, AAV2-lncTSI were injected intravenously to observe their effect on the formation of aortic valve calcification. RESULTS: lncTSI was highly expressed in VICs treated with TGF-ß1. lncTSI was transcriptionally regulated by Smad3 and reversely inhibited TGF-ß1-induced Smad3 phosphorylation and downregulated profibrotic gene expression. Silencing lncTSI increased TGF-ß1-induced Smad3 phosphorylation, and subsequently, upregulated RUNX2 and collagen I expressions in VICs. While overexpression of lncTSI reversed the production of RUNX2 and collagen I in VICs. In a mouse CAVD model of 24 week 0.25 % high-cholesterol diet feeding, overexpression of lncTSI significantly reduced calcium deposition, RUNX2, pSmad3, and collagen I expression in aortic valve leaflets, with less aortic valve stenosis. CONCLUSIONS: The novel findings of present study suggested that lncTSI alleviated aortic valve calcification through negative regulation of the TGF-ß/Smad3 pathway. The results may help elucidate new diagnostic and therapeutic targets to prevent CAVD progression.

Endoplasmic Reticulum Stress and Pathogenesis of Vascular Calcification.

Vascular calcification (VC) is characterized by calcium phosphate deposition in blood vessel walls and is associated with many diseases, as well as increased cardiovascular morbidity and mortality. However, the molecular mechanisms underlying of VC development and pathogenesis are not fully understood, thus impeding the design of molecular-targeted therapy for VC. Recently, several studies have shown that endoplasmic reticulum (ER) stress can exacerbate VC. The ER is an intracellular membranous organelle involved in the synthesis, folding, maturation, and post-translational modification of secretory and transmembrane proteins. ER stress (ERS) occurs when unfolded/misfolded proteins accumulate after a disturbance in the ER environment. Therefore, downregulation of pathological ERS may attenuate VC. This review summarizes the relationship between ERS and VC, focusing on how ERS regulates the development of VC by promoting osteogenic transformation, inflammation, autophagy, and apoptosis, with particular interest in the molecular mechanisms occurring in various vascular cells. We also discuss, the therapeutic effects of ERS inhibition on the progress of diseases associated with VC are detailed.

Donor-Recipient Weight Match in Pediatric Heart Transplantation: Liberalizing Weight Matching with Caution.

(1) Background: To expand the donor pool, greater donor hearts tended to be used in heart transplantation. However, the data about the feasibility of expanding the donor and recipient weight ratios (DRWRs. All donor and recipient weight ratio (DRWR) in this study or cited from other articles were converted to the DRWR calculated by ((donor weight-recipient weight)/recipient weight) × 100%.) to >30% was still scant in China's pediatric heart transplantation (HTx). The potential risk increased along with the further expansion of the appropriate range of DRWR to >30% and its upper limit was still in debate. (2) Methods: Seventy-eight pediatric patients (age < 18 years) undergoing HTx between 2015 and 2020 at our center were divided into two groups based on the DRWR (>30% and ≤30%). Variables were summarized and analyzed via univariate analyses and multivariate analyses. A Kaplan-Meier methodology was used to calculate survival and conditional survival. (3) Results: No significant difference was found in one-year, three-year or five-year survival between the two groups. (4) Conclusions: The expansion of DRWR to >30% was acceptable for China's pediatric HTx. Notably, continuously liberalizing of the upper DRWR boundary to more than 200% could be used as a stop-loss option but should be applied with caution.

Endothelial cell-derived tetrahydrobiopterin prevents aortic valve calcification.

AIMS: Tetrahydrobiopterin (BH4) is a critical determinant of the biological function of endothelial nitric oxide synthase. The present study was to investigate the role of valvular endothelial cell (VEC)-derived BH4 in aortic valve calcification. METHODS AND RESULTS: Plasma and aortic valve BH4 concentrations and the BH4:BH2 ratio were significantly lower in calcific aortic valve disease patients than in controls. There was a significant decrease of the two key enzymes of BH4 biosynthesis, guanosine 5'-triphosphate cyclohydrolase I (GCH1) and dihydrofolate reductase (DHFR), in calcified aortic valves compared with the normal ones. Endothelial cell-specific deficiency of Gch1 in Apoe-/- (Apoe-/-Gch1fl/flTie2Cre) mice showed a marked increase in transvalvular peak jet velocity, calcium deposition, runt-related transcription factor 2 (Runx2), dihydroethidium (DHE), and 3-nitrotyrosine (3-NT) levels in aortic valve leaflets compared with Apoe-/-Gch1fl/fl mice after a 24-week western diet (WD) challenge. Oxidized LDL (ox-LDL) induced osteoblastic differentiation of valvular interstitial cells (VICs) co-cultured with either si-GCH1- or si-DHFR-transfected VECs, while the effects could be abolished by BH4 supplementation. Deficiency of BH4 in VECs caused peroxynitrite formation increase and 3-NT protein increase under ox-LDL stimulation in VICs. SIN-1, the peroxynitrite generator, significantly up-regulated alkaline phosphatase (ALP) and Runx2 expression in VICs via tyrosine nitration of dynamin-related protein 1 (DRP1) at Y628. Finally, folic acid (FA) significantly attenuated aortic valve calcification in WD-fed Apoe-/- mice through increasing DHFR and salvaging BH4 biosynthesis. CONCLUSION: The reduction in endothelial-dependent BH4 levels promoted peroxynitrite formation, which subsequently resulted in DRP1 tyrosine nitration and osteoblastic differentiation of VICs, thereby leading to aortic valve calcification. Supplementation of FA in diet attenuated hypercholesterolaemia-induced aortic valve calcification by salvaging BH4 bioavailability.

Prediction of 1-year mortality after heart transplantation using machine learning approaches: A single-center study from China.

BACKGROUND: Heart transplantation (HTx) remains the gold-standard treatment for end-stage heart failure. The aim of this study was to establish a risk-prediction model for assessing prognosis of HTx using machine-learning approach. METHODS: Consecutive recipients of orthotopic HTx at our institute between January 1st, 2015 and December 31st, 2018 were included in this study. The primary outcome was 1-year mortality. Least absolute shrinkage and selection operator method was used to select variables and seven different machine-learning approaches were employed to develop the risk-prediction model. Bootstrap method was used for model validation. Shapley Additive exPlanations (SHAP) method was used for model interpretation. RESULTS: 381 recipients were included with average age of 43.783 years old. Albumin, recipient age and left atrium diameter ranked top three most important variables that affected the 1-year mortality of HTx. Other important variables included red blood cell, hemoglobin, lymphocyte%, smoking history, use of lyophilized rhBNP, use of Levosimendan, hypertension, cardiac surgery history, malignancy and endotracheal intubation history. Random Forest (RF) model achieved the best area under curves (AUC) of 0.801 and gradient boosting machine (GBM) showed the best sensitivity of 0.271. SHAP method was introduced to display the RF model's predicting processes of "survival" or "death" in individual level. CONCLUSIONS: We established the risk-prediction model for postoperative prognosis of HTx patients by using machine learning method and demonstrated that the RF model performed the highest discrimination with the largest AUC when validated. This prediction model could help to recognize high-risk HTx recipients, provide personalized therapy plan and reduce organ wastage.