CARDIOGEL - A BIOSYNTHETIC EXTRACELLULAR-MATRIX FOR CARDIOMYOCYTE CULTURE

Tissue-cultured neonatal cardiomyocytes can be successfully maintained in culture on a variety of extracellular matrix components such as la minin, fibronectin, and interstitial collagens (Types I and III). In v ivo, however, cardiomyocytes (as well as many other cells) exist in a highly complex extracellular matrix environment composed of, in additi on to the above three components, other proteins, proteoglycans, and g rowth factors. We have developed a procedure for culturing cardiomyocy tes on a naturally occurring complete extracellular matrix, Cardiogel. This substrate, synthesized by cardiac fibroblasts, contains laminin, fibronectin, Types I and III collagen, and proteoglycans. When compar ed to cardiomyocytes grown on laminin alone or fibronectin alone, Card iogel-supported cardiomyocytes adhere more rapidly after plating, exhi bit spontaneous contractility earlier, undergo cytoskeletal and myofib rillar differentiation earlier, and grow larger than their counterpart s. We suggest that their superior growth characteristics reflect the s ynergistic effect of numerous extracellular matrix components' signals in Cardiogel transduced by the cardiomyocyte cytoskeletal elements.