Cardiac remodeling and failure: From molecules to man (Part I)

The process of heart failure appears to be a common and coordinated response to cardiac injury and dysfunction. The contemporary mechanistic viewpoint that predictable, shared, highly regulated events underlie the complex heart failure process implies that an improved understanding of these mechanisms is fundamental to the advancement of cardiovascular biology and the subsequent development of targeted, effective treatment strategies for patients with congestive heart failure (CHF). Cardiac remodeling (CR) is the restructuring and reshaping of the heart that underlies heart failure progression. CR is a major determinant of the clinical course of CHF, irrespective of its etiology. The traditional concepts of cellular remodeling in the failing heart are based on well-established data indicating characteristic alterations in cell size, shape, and the ability to perform contractile work. The role of programmed cell death and the exciting possibility of cardiomyocyte regeneration are areas of intense investigation. Notably, the accumulating data in both animal and human hearts suggesting cardiomyocyte regeneration and renewal indicate that cellular remodeling is a complex and dynamic process that is not completely understood. For the development of new treatments to regenerate and restore failing myocardium, the possibilities offered by controlling cell death and enhancing cell renewal as a therapeutic target are unprecedented. Based on a critical review of the available literature, the traditional concepts and mechanisms describing the regulation of remodeling are largely inadequate. The neurohormonal (RAAS and adrenergic systems) and innovative cytokine hypothesis (TNF-α and others) of remodeling and failure do not account for all the cellular and molecular changes that result in the progression of CHF. Given that these contemporary concepts serve as the basis for the majority of our current heart failure treatments, it is not surprising that CHF is an emerging epidemic in our society. To define new therapeutic targets and to control the process of remodeling, novel biomolecules and mechanisms for the coordinated control of CR must be further defined.