Cardiac fibroblast-derived extracellular matrix produced in vitro stimulates growth and metabolism of cultured ventricular cells.

Cardiac fibroblasts (CFs) produce extracellular matrix (ECM) which is a potent regulator of heart cell function and growth, and provides a supportive microenvironment for heart cells. Therefore, CF-derived ECM produced in vitro is very suitable for heart-cell culturing and cardiac tissue engineering. The aim of this study was to investigate the effect of CF-derived ECM produced in vitro on the growth and metabolism of cultured ventricular cells. CF-derived ECM-coated cell culture dishes were prepared by culturing rat CFs and then decellularizing the cultures. Isolated neonatal rat ventricular cells were seeded on ECM-coated, collagen I-coated or uncoated dishes, and the growth of cells after 1-5 days of culture was assayed with MTT reagent. In addition, cellular metabolic activity was analyzed by spectrophotometric methods and protein levels of sarco(endo)plasmic reticulum Ca(2+)-ATPase type 2a (SERCA2a) by Western blotting. The relative growth of ventricular cells was better on ECM-coated than on uncoated or collagen I-coated dishes. Furthermore, the glucose consumption ratio, lactic acid production ratio, Na(+)/K(+)-ATPase activity, SERCA activity and protein levels of SERCA2a were all higher in cells on the ECM-coated dishes. In conclusion, cardiac fi broblast-derived ECM produced in vitro stimulates the growth and metabolism of cultured ventricular cells. This study indicates that the bioactivity of the ECM supports heart cell growth in vitro, and this might be useful for cardiac tissue engineering.