ISOLATION AND CHARACTERIZATION OF HUMAN CARDIAC FIBROBLASTS FROM EXPLANTED ADULT HEARTS

Fibrosis makes an important contribution to the pathophysiological eve nts leading to the development of heart failure in ischemic and hypert ensive heart disease. Since cardiac fibroblasts are mainly responsible for the synthesis and deposition of the extracellular matrix, we have established a method for isolating and cultivating human cardiac fibr oblasts from explanted human hearts. The cell yield was 2.14+/-0.25x10 (6) cells in five independent isolations and the cell purity was 95-97 %, contaminating cells being vascular smooth muscle cells and pericyte s. Cultured cells were studied with respect to growth properties, morp hology and deposition of components of the extracellular matrix. Isola ted cells displayed a differentiated phenotype, including the second p assage in culture; they synthesised collagen I, III, IV, fibronectin, vitronectin? tenascin and chondroitin sulphate and expressed an atypic al angiotensin receptor. This atypical angiotensin receptor internalis ed angiotensins II and III but not angiotensin IV in a time-dependent manner. Stimulation of the cells with angiotensins II and III but not with angiotensin IV resulted in a dose-dependent stimulation of DNA sy nthesis. Go-incubation with the subtype-specific receptor antagonists Losartan and PD 123317 did not prevent the stimulation of DNA synthesi s. The further characterisation of this receptor should provide insigh ts into the pathobiochemical events leading to heart failure in hypert ension and ischemic heart disease.