In Vivo Evaluation of a Decellularized Pericardium-polymer Biohybrid Composite for Use as a Cardiovascular Tissue Substitute

Abstract

Objective: Glutaraldehyde (GA) fixed bovine pericardium (BP) is the current gold standard for fabrication of bioprosthetic heart valves, despite their poor durability, lack of growth, risk of calcification and structural degeneration over time. These limitations make it unsuitable for use in children. Non-fixed, decellularized BP (dBP) has been tried as an alternative, but failed due to poor mechanical properties. In this study, our objective was to use a biodegradable polymer to treat dBP and improve its mechanical strength (Bio-Hybrid), and understand its remodeling potential in chronic animal implants. Methods: BP was decellularized using 2% sodium deoxycholate and its efficiency confirmed with DNA estimation and matrix analysis. The dBP was then coated with a layer of electrospun Polycaprolactone:Chitosan (PCL:Ch) to fabricate a Bio-Hybrid scaffold. The mechanical properties (uniaxial and biaxial), biocompatibility (cell adhesion, proliferation and cytotoxicity) and hemocompatibility (platelet adhesion, hemolysis and clot formation assay) of Bio-Hybrid material were assessed in comparison to GA treated BP. The in vivo biological response to the Bio-Hybrid material was evaluated in a rat subcutaneous model with GA treated BP as control material. Results: Decellularized BP showed significant reduction (p=0.0017) in DNA (49.05 + 41.09 ng/mg) compared to fresh BP (173.89 + 126.52 ng/mg). Electrospun PCL:Ch adhered to the decellularized BP, confirmed by FT-IR with unique peaks (1638.2, 1044.2 and 877.1 cm-1). Uniaxial mechanical testing showed significant increase in tensile extensibility (p=0.02) and the biaxial testing indicated an increase in the upper (p=0.002) and lower tangent modulus (p=0.0005) in the Bio-Hybrid. In vivo rat subcutaneous explants demonstrated higher cellular infiltration in the Bio-Hybrid scaffold along with remodeling of the extracellular matrix after 1, 4 and 12 weeks, compared to BP and dBP. Conclusions: BP modified with a synthetic polymer demonstrated favorable mechanical and remodeling potential, encouraging its pursuit as an alternative material for heart valve repair/replacement in children. KEYWORD: ICTEHV-O-13 The authors do not declare any conflict of interest.