Cardiomyocyte Cell Cycle Control

Abstract

Growth of the heart is traditionally divided into two phases. The initial phase of growth occurs during embryonic development and is characterized by the proliferation of differentiated, albeit immature, cardiomyocytes. The second phase of growth occurs after birth, and is characterized by hypertrophic growth of cardiomyocytes that have for the most part exited the cell cycle. Although cardiomyocyte DNA synthesis is observed in the adult heart, the magnitude and origin of these activities is debated. This chapter provides a brief review of mammalian cell cycle regulation, followed by a description of cardiomyocyte proliferation during development. Studies examining cardiomyocyte cell cycle activity in normal and injured adult hearts are then discussed. This is followed by a brief summary of efforts to enhance cardiomyocyte cell cycle activity using biochemical (i.e. addition of exogenous growth factors, cytokines, etc) or genetic (i.e. altering gene expression via gene transfer or gene ablation approaches, etc) interventions.