Abstract 425: RGD-coupling To Collagen Scaffold Improves Cardiomyocyte Viability And Contractility: New Possibilities For Cardiac Tissue Engineering
Cardiac tissue engineering is an emerging field that holds great promise for replacement therapy of diseased myocardium or repair of cardiac malformations. However, the creation of functional, biocompatible contractile tissues remains challenging. Obvious concerns relate to the immunogenicity, safety and practical implementation of collagen-cell scaffolds (CCS). We hypothesized that efficient cardiomyocyte cell loading and the contractile function of CCS could be improved by coupling RGD peptides to clinically approved collagen scaffold (Ultrafoam). Collagen-cross-linked RGD+ scaffolds (RGD +, n = 16) were seeded with neonatal ventricular myocardial cells (1.2.107 cells/cm3). Contractile performance, cardiomyocyte viability and differentiation were analyzed at day 8. RGD- scaffolds (n =11) were used as controls. The method used for the RGD-collagen scaffold coupling allows i) high coupling yields and complete washout of excess reagent and by-products with no need for chromatography; ii) spectroscopic quantification of RGD coupling; iii) a spacer arm of 36 angstroms, a length reported as optimal for RGD peptide presentation and favorable for integrin receptor clustering and subsequent activation. In both RGD- and RGD +, active force (AF) reached a maximum value at 0.17 Hz stimulation frequency and decreased with increased stimulation frequency. Whatever the stimulation frequency, AF and +dP/dt were nearly 2-fold higher in RGD + than in RGD-constructs (each p<0.05). At optimal stimulation frequency, RGD + had nearly 3-fold increase in both maximum extent of shortening (31.1 ± 3.1 vs 9.4 ± 3.9 um, p<0.05) and maximum shortening velocity (633.0 ± 180.8 vs 256.5 ± 55.0 um/s, p<0.05) than RGD-. At day 8, RGD-constructs contained almost exclusively round cells that were poorly attached to the matrix. In contrast, cardiomyocytes in RGD + constructs were aligned, elongated, and exhibited cross-striations of mature cardiomyocytes. In conclusion, we report a novel method of engineering a highly effective and stable CCS based on a clinically approved collagen matrix cross-linked to RGD peptides. Here we demonstrate its advantages in terms of contractile performance, cardiomyocyte viability and differentiation.