Ontogeny of Enhanced Decorin Levels and Distribution Within Myocardium of Failing Hearts

The proteoglycan, decorin, is a regulator of collagen fibril organization and its resulting functional properties. The temporal and spatial expression of decorin during the progression to heart failure is not well understood and may play a significant role in extracellular matrix remodeling. Decorin and types I and III collagen levels were measured in male Spontaneously Hypertensive Heart Failure (SHHF) and control Wistar-Furth rats at 2 and 8 mo, and at congestive heart failure (CHF). Decorin levels increased in the SHHF rats relative to the control rats in CHF. Type I collagen levels increased while type III levels decreased in the SHHF rats in CHF relative to the age matched controls. The SHHF rats have 48 and 45 KDa isoforms of the decorin core protein expressed at all ages while control Wistar-Furths produced only a 45 KDa form. Decorin was localized in the outer ventricle wall but during CHF, decorin was expressed throughout the ventricular myocardium. Immunogold localization of decorin demonstrated an increased distribution of decorin along the myocardium collagen fibrils at CHF. The enhanced expression and greater distribution of decorin may be linked to extracellular matrix remodeling which occurs with the development of heart failure.