Development of 3-Dimensional Prevascularized Scaffold-Free Contractile Cardiac Patch for Heart Regeneration

Abstract

Purpose The aim of our study is to develop completely scaffold-free, viable, contractile cardiac tissue which can be grafted to the damaged native heart. Methods and Materials Our technology is based on the fundamental characteristics of self-assembling nature of cells. We called these self-assembled spherical cell aggregates as “spheroids”. We created contractile cardiac spheroids by plating a mixture of 800 cells of rat neonate ventricular cardiomyocytes (RNVCM), 100 cells of human normal dermal fibroblasts (HNDFB), and 100 cells of human coronary micro-artery endothelial cells (HCMEC) in ultra-low-attachment plate. After 24 hr cultivation, prevascularized contractile cardiac spheroids were fabricated. Next, 10000 spheroids were fused into patch like construct with a maximum diameter of 1cm with 200μm in thickness. We evaluated morphological characteristics, and electro- and mechanical function. We also grafted the cardiac patch onto the heart of F344 nude rats, and performed histological study 3 weeks after transplantation. Results We confirmed synchronous beating of the cardiac patch electro-physiologically, and mechanically (video-motion analysis). Expression of connexin 43 (a component of gap junction) and micro network of endothelial cell in the construct were demonstrated. Histological study performed 3 weeks after transplantation showed that the grafts were viable with functioning micro-vascular structure inside the graft. [ figure 1 ] Conclusions We consider that applying our scaffold-free 3-Dimensinal tissue engineering technology to cardiac regeneration therapy is feasible. We expect that this technology will become a promising tool to treat end-stage heart failure.