Investigation of cardiac fibroblasts using myocardial slices

Aims: Cardiac fibroblasts (CFs) are considered the principal regulators of cardiac fibrosis. Factors that influence CF activity are difficult to determine. When isolated and cultured in vitro , CFs undergo rapid phenotypic changes including increased expression of α-SMA. Here we describe a new model to study CFs and their response to pharmacological and mechanical stimuli using in vitro cultured mouse, dog and human myocardial slices. Methods and Results: Unloading of myocardial slices induced CF proliferation without α-SMA expression up to 7 days in culture . CFs migrating onto the culture plastic support or cultured on glass expressed αSMA within 3 days. The cells on the slice remained αSMA(-) despite TGF-β (20ng/mL) or angiotensin II (200µM) stimulation. When diastolic load was applied to myocardial slices using A-shaped stretchers, CF proliferation was significantly prevented at day 3 and 7 (P < 0.001). Conclusions: Myocardial slices allow the study of CFs in a multicellular environment and may be used to effectively study mechanisms of cardiac fibrosis and potential targets