What triggers RV Fiber Re-Orientation in response to RV pressure overload, and what is its Consequence on Inter-Ventricular Decoupling?

是什么触发了右心室纤维重新定向以响应右心室压力过载，以及它对心室间解耦的影响是什么？

• 批准号: 10587587
• 负责人: Vitaly Kheyfets
• 金额: $ 49.18万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10587587
• 关键词: Adopted; Animals; Biological; Cardiac; Cardiac Myocytes; Catheterization; Cause of Death; Characteristics; Child; Collagen; Computer Models; Contracts; Coupling; Data; Data Set; Deterioration; Diffusion; Energy Transfer; Failure; Female; Fiber; Fibrosis; Focal Adhesions; Future; Gender; Gene Expression; Genes; Genetic Transcription; Geometry; Heart; Image; Interruption; Left; Left ventricular structure; Lung; Machine Learning; Magnetic Resonance Imaging; Matrix Metalloproteinases; Mechanical Stress; Mechanics; Modeling; Mus; Myocardial; Myosin Heavy Chains; Observational Study; Operative Surgical Procedures; Pathway interactions; Patient-Focused Outcomes; Physiologic intraventricular pressure; Process; Progressive Disease; Protein Isoforms; Pulmonary Heart Disease; Pulmonary Hypertension; Pump; Research; Right Ventricular Dysfunction; Right Ventricular Function; Right ventricular structure; Role; Signal Transduction Pathway; Stress; Systole; Time; Tissues; Torsion; Ventricular; Ventricular Ejection Fractions; aorta constriction; clinical practice; connectin; coping; functional decline; improved; improved outcome; in silico; innovation; male; mechanical energy; mechanical stimulus; mortality; mouse model; preservation; pressure; protein expression; pulmonary vascular disorder; response; right ventricular failure; right ventricular remodeling; simulation; targeted treatment; therapeutic target

PROJECT SUMMARY Pulmonary hypertension (PH) is a cardiopulmonary disease that ultimately leads to right ventricular (RV) failure. Currently there are no approved therapies targeting the RV and most research is focused on reducing fibrosis, although it is unclear if this will ultimately improve RV pumping function. However, the orientation of collagen and cardiomyocyte fibers likely have a major influence on RV function and are largely overlooked in ongoing research and clinical practice. Furthermore, the role of the left ventricle (LV) in RV function is almost completely discounted, but previous research from the 90’s has suggested that the LV is more important for RV function than the contracting RV free wall. Our preliminary data shows that LV torsion rate is reduced in children with PH and in mice after pulmonary arterial banding (PAB), which is correlated with reduced RV ejection fraction in both species. However, when we induced LV pressure overload in the PAB mice (by partial aortic constriction), we improved their LV torsion rate and RV systolic function. This was further validated with in silico studies of the bi-ventricular heart, which showed that targeting LV torsion rate could improve RV systolic function, but it depends on RV free wall fiber orientation. Therefore, these results left us with the following questions: (1) What new orientation do the fibers adopt in response to pressure overload (our preliminary results are not consistent with others), and does this new orientation improve or worsen RV function? (2) How does RV fiber re-orientation impact LV-to-RV mechanical assistance during systole? (3) How does the transient fiber re-orientation and stiffening impact mechanical stress/strain within the tissue, and how does that impact -or is driven by- gene expression? In this study, we will combine the PAB mouse model with in silico simulations to investigate how changes in RV fiber orientation and stiffening, in the RV free wall, impact RV pumping function. Then, we will combine PAB with aortic constriction to study how RV remodeling interferes with LV torsion and if this interrupts LV-to-RV mechanical assistance during systole. Finally, by collecting a time course dataset of imaging and gene expression, we will identify genes that are directly impacted by changes in mechanical stress and expose how they trigger their downstream remodeling pathways. The questions being answered in this project will lead to a better understanding of how RV structural remodeling, in response to pressure overload, impacts RV function and interventricular coupling, and identify target genes governing this process for future studies.

项目总结