Project description:This study evaluates the effectiveness of myocardial matrix (MM) hydrogels in mitigating negative right ventricular (RV) remodeling in a rat model of RV heart failure. The goal was to assess whether a hydrogel derived from either the right or left ventricle could promote cardiac repair. Injured rat right ventricles were injected with either RV-or left ventricular-derived MM hydrogels. Both hydrogels improved RV function and morphology and reduced negative remodeling. This study supports the potential of injectable biomaterial therapies for treating RV heart failure.
Project description:BackgroundRight ventricular (RV) dysfunction contributes to mortality in chronic heart failure (HF). However, the molecular mechanisms of RV failure remain poorly understood, and RV myocardial biomarkers have yet to be developed.Methods and resultsWe performed RNA sequencing (RNA-seq) on 22 explanted human HF RVs and 5 unused donor human heart RVs (DON RV) and compared results to those recently reported from 16 explanted human LVs We used Bowtie-Tophat for transcript alignment and transcriptome assembly, DESeq for identification of differentially expressed genes (DEGs) and Ingenuity for exploration of gene ontologies. In the HF RV, RNA-seq identified 130,790 total RNA transcripts including 13,272 protein coding genes, 10,831 long non-coding RNA genes and 8,605 pseudogenes. There were 800-1000 DEGs between DON and HF RV comparison groups with differences concentrated in cytoskeletal, basement membrane, extracellular matrix (ECM), inflammatory mediator, hemostasis, membrane transport and transcription factor genes, lncRNAs and pseudogenes. In an unbiased approach, the top 10 DEGs SERPINA3, SERPINA5, LCN6, LCN10, STEAP4, AKR1C1, STAC2, SPARCL1, VSIG4 and F8 exhibited no overlap in read counts between DON and HF RVs, high sensitivities, specificities, predictive values and areas under the receiver operating characteristic curves. STEAP4, SPARCL1 and VSIG4 were differentially expressed between RVs and LVs, supporting their roles as RV-specific myocardial biomarkers.ConclusionsUnbiased, comprehensive profiling of the RV transcriptome by RNA-seq suggests structural changes and abnormalities in inflammatory processes and yields specific, novel HF RV vs HF LV myocardial biomarkers not previously identified by more limited transcriptome profiling approaches.
Project description:Acute respiratory distress syndrome (ARDS) is burdened with significant mortality, mainly in connection with circulatory failure. The right ventricle (RV) is the weak link of hemodynamic stability among ARDS patients and its failure, also named "severe" acute cor pulmonale (ACP), is responsible for excess mortality. Driving pressure ≥18 cmH2O, PaCO2 ≥48 mmHg and PaO2/FiO2 <150 mmHg are three preventable factors recently identified as independently associated with ACP, on which ventilator strategy designed to protect the RV has to focus. This is largely achieved by the use of early and extended sessions of prone positioning (PP) and by daily monitoring of the RV by echocardiography.
Project description:Pulmonary arterial hypertension (PAH) is a fatal disease for which no cure is yet available. The leading cause of death in PAH is right ventricular (RV) failure. Previously, the TNF receptor superfamily member fibroblast growth factor-inducible molecule 14 (Fn14) has been associated with different fibrotic diseases. However, so far there is no study demonstrating a causal role for endogenous Fn14 signaling in RV or LV heart disease. The purpose of this study was to determine whether global ablation of Fn14 prevents RV fibrosis and remodeling improving heart function. Here, we provide evidence for a causative role of Fn14 in pulmonary artery banding (PAB)-induced RV fibrosis and dysfunction in mice. Fn14 expression was increased in the RV after PAB. Mice lacking Fn14 (Fn14(-/-)) displayed substantially reduced RV fibrosis and dysfunction following PAB compared to wild-type littermates. Cell culture experiments demonstrated that activation of Fn14 induces collagen expression via RhoA-dependent nuclear translocation of myocardin-related transcription factor-A (MRTF-A)/MAL. Furthermore, activation of Fn14 in vitro caused fibroblast proliferation and myofibroblast differentiation, which corresponds to suppression of PAB-induced RV fibrosis in Fn14(-/-) mice. Moreover, our findings suggest that Fn14 expression is regulated by endothelin-1 (ET-1) in cardiac fibroblasts. We conclude that Fn14 is an endogenous key regulator in cardiac fibrosis and suggest this receptor as potential new target for therapeutic interventions in heart failure.
Project description:Receptor-interacting protein kinase 1 (RIPK1) and 3 (RIPK3) are critical regulators of programmed necrosis or necroptosis. However, the role of the RIPK1/RIPK3 signaling pathway in myocardial fibrosis and related diabetic cardiomyopathy is still unclear. We hypothesized that RIPK1/RIPK3 activation mediated myocardial fibrosis by impairing the autophagic flux. To this end, we established in vitro and in vivo models of type 2 diabetes mellitus with high glucose fat (HGF) medium and diet respectively. HGF induced myocardial fibrosis, and impaired cardiac diastolic and systolic function by activating the RIPK1/RIPK3 pathway, which increased the expression of autophagic related proteins such as LC3-II, P62 and active-cathepsin D. Inhibition of RIPK1 or RIPK3 alleviated HGF-induced death and fibrosis of cardiac fibroblasts by restoring the impaired autophagic flux. The autophagy blocker neutralized the effects of the RIPK1 inhibitor necrostatin-1 (Nec-1) and RIPK3 inhibitor GSK872 (GSK). RIPK1/RIPK3 inhibition respectively decreased the levels of RIPK3/p-RIPK3 and RIPK1/p-RIPK1. P62 forms a complex with RIPK1-RIPK3 and promotes the binding of RIPK1 and RIPK3, silencing of RIPK1 decreased the association of RIPK1 with P62 and the binding of P62 to LC3. Furthermore, inhibition of both kinases in combination with a low dose of Nec-1 and GSK in the HGF-treated fibroblasts significantly decreased cell death and fibrosis, and restored the autophagic flux. In the diabetic rat model, Nec-1 (1.65 mg/kg) treatment for 4 months markedly alleviated myocardial fibrosis, downregulated autophagic related proteins, and improved cardiac systolic and diastolic function. In conclusion, HGF induces myocardial fibrosis and cardiac dysfunction by activating the RIPK1-RIPK3 pathway and by impairing the autophagic flux, which is obviated by the pharmacological and genetic inhibition of RIPK1/RIPK3.
Project description:Myocardial fibrosis, measured using cardiovascular magnetic resonance extracellular volume (ECV), is associated with adverse outcome in heart failure with preserved ejection fraction, but the mechanisms by which myocardial fibrosis exerts this deleterious effect are unclear. We performed mediation analyses of data from the Pirfenidone in Patients with Heart Failure and Preserved Left Ventricular Ejection Fraction (PIROUETTE) trial to determine whether myocardial fibrotic regression causes changes in cardiovascular function and functional status following antifibrotic therapy. Regression of myocardial fibrosis correlated with improvements in 6-min walk test and KCCQ clinical summary score. The only outcome variable that demonstrated a treatment effect was an increase in left ventricular ejection fraction (LVEF). The estimated average causal mediation effects of myocardial ECV, absolute myocardial extracellular matrix volume and absolute myocardial cellular volume on LVEF were 6.1%, 21.5% and 13.7%, respectively, none of which was significant and therefore not mediated by myocardial fibrosis. (PIROUETTE; NCT02932566).
Project description:Background Hypertensive myocardial fibrosis (MF) is characterized by excessive deposition of extracellular matrix and cardiac fibroblast proliferation, which can lead to heart failure, malignant arrhythmia, and sudden death. In recent years, with the deepening of research, microRNAs have been found to have an important role in blood pressure control and maintaining normal ventricular structure and function. Methods and Results In this study, we first documented the downregulation of microRNA-26a (miR-26a) in the plasma and myocardium of spontaneously hypertensive rats; more importantly, miR-26a-deficient mice showed MF, whereas overexpression of miR-26a significantly prevented elevated blood pressure and inhibited MF in vivo and angiotensin II-induced fibrogenesis in cardiac fibroblasts by directly targeting connective tissue growth factor and Smad4. miR-26a inhibited cardiac fibroblast proliferation by the enhancer of zeste homolog 2/p21 pathway. Conclusions Our study identified a novel role for miR-26a in blood pressure control and hypertensive MF and provides a possible treatment strategy for miR-26a to alleviate and reverse hypertensive MF.
Project description:BackgroundHepatic fibrosis progresses with right heart failure, and becomes cardiac cirrhosis in a severe case. Although its causal factor still remains unclear. Here we evaluated the progression of hepatic fibrosis using a pulmonary artery banding (PAB)-induced right heart failure model and investigated whether cardiac output (CO) is responsible for the progression of hepatic fibrosis.Methods and resultsFive-week-old Sprague-Dawley rats divided into the PAB and sham-operated control groups. After 4 weeks from operation, we measured CO by echocardiography, and hepatic fibrosis ratio by pathological examination using a color analyzer. In the PAB group, CO was significantly lower by 48% than that in the control group (78.2±27.6 and 150.1±31.2 ml/min, P<0.01). Hepatic fibrosis ratio and serum hyaluronic acid, an index of hepatic fibrosis, were significantly increased in the PAB group than those in the control group (7.8±1.7 and 1.0±0.2%, P<0.01, 76.2±27.5 and 32.7±7.5 ng/ml, P<0.01). Notably, the degree of hepatic fibrosis significantly correlated a decrease in CO. Immunohistological analysis revealed that hepatic stellate cells were markedly activated in hypoxic areas, and HIF-1? positive hepatic cells were increased in the PAB group. Furthermore, by real-time PCR analyses, transcripts of profibrotic and fibrotic factors (TGF-?1, CTGF, procollargen I, procollargen III, MMP 2, MMP 9, TIMP 1, TIMP 2) were significantly increased in the PAB group. In addition, western blot analyses revealed that the protein level of HIF-1? was significantly increased in the PAB group than that in the control group (2.31±0.84 and 1.0±0.18 arbitrary units, P<0.05).ConclusionsOur study demonstrated that low CO and tissue hypoxia were responsible for hepatic fibrosis in right failure heart model rats.
Project description:BackgroundDiabetes is associated with myocardial fibrosis, while the underlying mechanisms remain elusive. The aim of this study is to investigate the underlying role of calcineurin/nuclear factor of activated T cell 3 (CaN/NFATc3) pathway and the Enhancer of zeste homolog 2 (EZH2) in diabetes-related myocardial fibrosis.MethodsStreptozotocin (STZ)-injected diabetic rats were randomized to two groups: the controlled glucose (Con) group and the diabetes mellitus (DM) group. Eight weeks later, transthoracic echocardiography was used for cardiac function evaluation, and myocardial fibrosis was visualized by Masson trichrome staining. The primary neonatal rat cardiac fibroblasts were cultured with high-glucose medium with or without cyclosporine A or GSK126. The expression of proteins involved in the pathway was examined by western blotting. The nuclear translocation of target proteins was assessed by immunofluorescence.ResultsThe results indicated that high glucose treatment increased the expression of CaN, NFATc3, EZH2 and trimethylates lysine 27 on histone 3 (H3K27me3) in vitro and in vivo. The inhibition of the CaN/NFATc3 pathway alleviated myocardial fibrosis. Notably, inhibition of CaN can inhibit the nuclear translocation of NFATc3, and the expression of EZH2 and H3K27me3 protein induced by high glucose. Moreover, treatment with GSK126 also ameliorated myocardial fibrosis.ConclusionDiabetes can possibly promote myocardial fibrosis by activating of CaN/NFATc3/EZH2 pathway.