semaxinib and Heart-Failure

Right heart failure is the leading cause of death in pulmonary hypertension (PH), and echocardiography is a commonly used tool for evaluating the risk hierarchy of PH. However, few studies have explored the dynamic changes in the structural and functional changes of the right heart during the process of PH. Previous studies have found that pulmonary circulation coupling right ventricular adaptation depends on the degree of pressure overload and other factors. In this study, we performed a time-dependent evaluation of right heart functional changes using transthoracic echocardiography in a SU5416 plus hypoxia (SuHx)-induced PH rat model. Rats were examined in 1-, 2-, 4-, and 6-week using right-heart catheterization, cardiac echocardiography, and harvested heart tissue. Our study found that echocardiographic measures of the right ventricle (RV) gradually worsened with the increase of right ventricular systolic pressure, and right heart hypofunction occurred at an earlier stage than pulmonary artery thickening during the development of PH. Furthermore, sarco-endoplasmic reticulum calcium ATPase 2 (SERCA2), a marker of myocardial damage, was highly expressed in week 2 of SuHx-induced PH and had higher levels of expression of γ-H2AX at all timepoints, as well as higher levels of DDR-related proteins p-ATM and p53/p-p53 and p21 in week 4 and week 6. Our study demonstrates that the structure and function of the RV begin to deteriorate with DNA damage and cellular senescence during the early stages of PH development.

Topics: Animals; DNA Damage; Echocardiography; Heart Failure; Hypertension, Pulmonary; Hypoxia; Rats; Tumor Suppressor Protein p53

Right ventricular (RV) dysfunction is a significant prognostic determinant of morbidity and mortality in pulmonary arterial hypertension (PAH). Despite the importance of RV function in PAH, the underlying molecular mechanisms of RV dysfunction secondary to PAH remain unclear. We aim to identify and compare molecular determinants of RV failure using RNA sequencing of RV tissue from 2 clinically relevant animal models of PAH.. We performed RNA sequencing on RV from rats treated with monocrotaline or Sugen with hypoxia/normoxia. PAH and RV failure were confirmed by catheterization and echocardiography. We validated the RV transcriptome results using quantitative real-time polymerase chain reaction, immunofluorescence, and Western blot. Immunohistochemistry and immunofluorescence were performed on human RV tissue from control (n=3) and PAH-induced RV failure patients (n=5).. We identified similar transcriptomic profiles of RV from monocrotaline- and Sugen with hypoxia-induced RV failure. Pathway analysis showed genes enriched in epithelial-to-mesenchymal transition, inflammation, and metabolism. Histological staining of human RV tissue from patients with RV failure secondary to PAH revealed significant RV fibrosis and endothelial-to-mesenchymal transition, as well as elevated cellular communication network factor 2 (top gene implicated in epithelial-to-mesenchymal transition/endothelial-to-mesenchymal transition) expression in perivascular areas compared with normal RV.. Transcriptomic signature of RV failure in monocrotaline and Sugen with hypoxia models showed similar gene expressions and biological pathways. We provide translational relevance of this transcriptomic signature using RV from patients with PAH to demonstrate evidence of epithelial-to-mesenchymal transition/endothelial-to-mesenchymal transition and protein expression of cellular communication network factor 2 (CTGF [connective tissue growth factor]). Targeting specific molecular mechanisms responsible for RV failure in monocrotaline and Sugen with hypoxia models may identify novel therapeutic strategies for PAH-associated RV failure.

Topics: Aged; Aged, 80 and over; Angiogenesis Inhibitors; Animals; Disease Models, Animal; Epithelial-Mesenchymal Transition; Female; Gene Expression Profiling; Heart Failure; Heart Ventricles; Humans; Hypoxia; Indoles; Male; Middle Aged; Monocrotaline; Pulmonary Arterial Hypertension; Pyrroles; Rats; Real-Time Polymerase Chain Reaction; RNA-Seq; Transcriptome; Ventricular Dysfunction, Right; Ventricular Remodeling