Isolation and characterization of rabbit cardiac endothelial cells: response to cyclic strain and growth factors in vitro.

Studies of the cardiac endothelium have been complicated by difficulties in isolating and maintaining cardiac endothelial cells (EC) in culture. We present in this paper a method of obtaining pure EC from rabbit hearts by collagenase digestion and membrane filtration. Pure cultures of EC displaying characteristic EC morphology, uptake of di-I-acetylated LDL, and contact-inhibition of growth were successfully maintained in culture for several weeks in media supplemented with fetal bovine serum, bovine retina-derived growth factor (RDGF), and antibiotics. Since EC in vivo are exposed to a complex pattern of physical forces we also sought to determine the proliferative response of cardiac EC subjected to pulsatile strain in vitro and compared it with the response to the addition of an exogenous growth factor, RDGF. The results demonstrate that a regimen of 60 cycles per minute, 24% cyclic strain induced a significant increase in cardiac EC proliferation and suggests that physical forces may have a trophic effect on EC proliferation.