Differential Behaviors of Atrial Versus Ventricular Fibroblasts A Potential Role for Platelet-Derived Growth Factor in Atrial-Ventricular Remodeling Differences

TLDR: Atrial fibroblasts behave differently than ventricular fibro Blasts over a range of in vitro and in vivo paradigms, with atrial Fibroblast showing enhanced reactivity that may explain greater atrial fibrotic responses.

Abstract: Background— In various heart disease paradigms, atria show stronger fibrotic responses than ventricles. The possibility that atrial and ventricular fibroblasts respond differentially to pathological stimuli has not been examined. Methods and Results— We compared various morphological, secretory, and proliferative response indexes of canine atrial versus ventricular fibroblasts. Cultured atrial fibroblasts showed faster cell surface area increases, distinct morphology at confluence, and greater α-smooth muscle actin expression than ventricular fibroblasts. Atrial fibroblast proliferation ([3H]thymidine incorporation) responses were consistently greater for a range of growth factors, including fetal bovine serum, platelet-derived growth factor (PDGF), basic fibroblast growth factor, angiotensin II, endothelin-1, and transforming growth factor-β1. Normal atrial tissue showed larger myofibroblast density compared with ventricular tissue, and the difference was exaggerated by congestive heart failure. Congesti...