Multiscale analysis of human tissue engineered matrices for next generation heart valve applications

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Cardiovascular Research

Background:

• Human tissue-engineered matrices (hTEMs) are promising for engineered heart valves (TEHVs).
• Limited understanding exists regarding extracellular matrix (ECM) development in hTEMs over culture time.
• Characterizing ECM composition and its impact on mechanical properties is crucial for TEHV development.

Purpose of the Study:

• To longitudinally assess ECM composition and mechanical properties of hTEMs during tissue culture.
• To analyze protein pathways involved in ECM development within hTEMs.
• To evaluate the performance of TEHVs fabricated from mature hTEMs.

Main Methods:

• Multiscale evaluation of hTEM composition using histology, biochemical assays, and LC-MS/MS over 2, 4, and 6 weeks.
• Gene set enrichment analysis (GSEA) to identify ECM-related protein pathways.
• Uniaxial tensile testing for mechanical characterization.
• In vitro testing of TEHVs in a pulse duplicator.

Main Results:

• LC-MS/MS confirmed time-dependent increases in ECM proteins like collagens, proteoglycans, and glycoproteins.
• GSEA revealed distinct protein pathways at different culture times: mRNA metabolism (2 weeks), ECM production (4 weeks), and ECM organization (6 weeks).
• Mechanical testing showed increased stiffness and stress at failure, with reduced strain over culture time.
• hTEM-based TEHVs exhibited promising in vitro performance under pulmonary and aortic pressure conditions.

Conclusions:

• ECM protein abundance and maturation increase with tissue culture time in hTEMs.
• Extended tissue culture enhances hTEM mechanical characteristics, making them suitable for high-pressure applications.
• These findings are vital for translating hTEM-based TEHVs into clinical practice and predicting their in vivo remodeling potential.