Use of myocardial matrix in a chitosan-based full-thickness heart patch.

A novel cardiac scaffold comprised of decellularized porcine heart matrix was investigated for use as a biodegradable patch with a potential for surgical reconstruction of the right ventricular outflow tract. Powdered heart matrix solution was blended with chitosan and lyophilized to form three-dimensional scaffolds. For this investigation, we examined the influence of different blending ratios of heart matrix to chitosan on porosity and mechanical properties, then gene expression and electrophysiological function of invading neonatal rat ventricular myocytes (NRVM) compared to type-A gelatin/chitosan composite scaffolds. Heart matrix/chitosan-blended hydrogels (1.6 mg/mL heart matrix) had similar porosity (109±34 μm), and elastic modulus (13.2±4.0 kPa) as previously published gelatin/chitosan scaffolds. Heart matrix/chitosan hydrogels maintained>80% viability and had higher NRVM retention (∼1000 cells/mm(2)) than gelatin/chitosan scaffolds. There was a significant increase in α-myosin heavy chain and connexin-43 expression in NRVM cultured on heart matrix/chitosan scaffolds after 14 days compared with gelatin/chitosan scaffolds. Further, heart matrix/chitosan scaffolds had significantly higher conduction velocity (12.6±4.9 cm/s) and contractile stress (0.79±0.13 mN/mm(2)) than gelatin/chitosan scaffolds. In summary, NRVM cultured on heart matrix scaffold showed improvements in contractile and electrophysiological function.