Novel 3D culture system for study of cardiac myocyte development.

Insufficient myocardial repair after pathological processes contributes to cardiovascular disease, which is a major health concern. Understanding the molecular mechanisms that regulate the proliferation and differentiation of cardiac myocytes will aid in designing therapies for myocardial repair. Models are needed to delineate these molecular mechanisms. Here we report the development of a model system that recapitulates many aspects of cardiac myocyte differentiation that occur during early cardiac development. A key component of this model is a novel three-dimensional tubular scaffold engineered from aligned type I collagen strands. In this model embryonic ventricular myocytes undergo a transition from a hyperplastic to a quiescent phenotype, display significant myofibrillogenesis, and form critical cell-cell connections. In addition, embryonic cardiac myocytes grown on the tubular substrate have an aligned phenotype that closely resembles in vivo neonatal ventricular myocytes. We propose that embryonic cardiac myocytes grown on the tube substrate develop into neonatal cardiac myocytes via normal in vivo mechanisms. This model will aid in the elucidation of the molecular mechanisms that regulate cardiac myocyte proliferation and differentiation, which will provide important insights into myocardial development.