Heart Valve Injury Model

Indication and Application:

Validation of structural heart medical devices (e.g., transcatheter aortic/mitral valve replacement or repair systems, transcatheter edge-to-edge repair / TEER), evaluation of anti-calcification treatments and coatings, preclinical testing of antimicrobial therapies for infective endocarditis, and research on leaflet thrombosis and remodeling kinetics.

Modeling Method:

• Catheter-Induced Mechanical Injury (Rodents/Large Animals): Under continuous fluoroscopic or echocardiographic guidance, a specialized guide wire or indwelling polyethylene catheter is introduced via the right carotid artery and advanced retrogradely across the aortic valve. The catheter is moved repeatedly across the valve leaflets to cause localized endothelial denudation and disruption of the extracellular matrix.

• Indwelling Catheter Model (Infective Endocarditis Validation): For infectious profiling, the catheter is left placed across the valve for a designated period (e.g., 24 hours) followed by a calibrated intravenous injection of pathogenic bacteria (e.g., Staphylococcus aureus or Streptococcus mutans) to induce robust, bacterial-laden valvular vegetations.

Clinical Relevance:

• Pathological Correlation: The mechanical disruption of the valvular endotheium triggers immediate platelet-fibrin deposition, establishing non-bacterial thrombotic endocarditis (NBTE), which serves as the essential clinical prerequisite for bacterial colonization or calcific degeneration.

• Structural Heart Evaluation Platform: In sheep and porcine variations, the dimensions and hemodynamic parameters of the aortic and mitral valves closely resemble human anatomy. This provides a rigorous, translationally valid platform to assess paravalvular leak (PVL), structural valve deterioration (SVD), and leaf-anchoring stability for cutting-edge transcatheter devices prior to entering human clinical trials.

Key Evaluation Endpoints:

1. In Vivo / Surgical / Imaging:

• High-Resolution Echocardiography (Transthoracic/Transesophageal Echocardiography - TTE/TEE): Real-time longitudinal monitoring of transvalvular pressure gradients, peak velocity, jet area of valvular regurgitation (insufficiency), and the presence or size of mobile valvular vegetations.

• Continuous Hemodynamic Monitoring: Measurement of left ventricular end-diastolic pressure (LVEDP) and aortic root pressure waves to quantify the severity of acute valvular insufficiency.

• Microbiological Assays (For IE Models): Longitudinal quantitative blood cultures to confirm persistent bacteremia and determine systemic bacterial load.

2. Histopathology:

• Valvular Structure Assessment (Gold Standard): H&E and Masson's Trichrome staining to evaluate leaflet thickening, structural distortion, matrix remodeling, and collagen organization.

• Vegetation and Thrombosis Profiling: Brown-Brenn (Gram) staining to visualize localized bacterial clusters within the vegetations, and Von Kossa or Alizarin Red staining to quantify intra-leaflet calcification and mineralization.

• IHC/IF: Profiling of endothelial lining integrity (CD31, vWF), inflammatory cell recruitment (CD68 for macrophages, myeloperoxidase for neutrophils), and myofibroblast activation (alpha-SMA).

3. Molecular:

• Expression analysis of osteogenic and calcification markers (e.g., Runx2, Osteopontin, BMP-2) or inflammatory cytokines (TNF-alpha, IL-1beta) via RT-qPCR or Western Blotting to determine the performance of protective pharmaceutical compounds or biomaterial modifications.

Regulatory-Grade Data Package (OECD GLP, AAALAC, CMA, CNAS):

As a premier preclinical CRO specializing in structural heart disease, all study protocols at HuaTeng Biotechnology comply fully with global regulatory framework standards. Our high-resolution intraoperative imaging (TEE and fluoroscopy) coupled with precise, computerized histomorphometric analysis ensures low data dispersion and high reproducibility, delivering robust data packages engineered to support international IND and medical device regulatory approvals.