Incorporation of beta-galactosidase-expressing endothelial cells into the skeletal muscle microvascular bed of mice

Cloned murine endothelial cells (cEC) were used as a carrier system for introducing a foreign gene into the microvascular bed of the hind limb of inbred mice. cEC were transfected with a beta-galactosidase-neo fusion construct, which enables both selection for DNA uptake in the presence of G 418 and the staining of cells for beta-galactosidase activity. Transfected cEC adhered and integrated readily into confluent monolayers of nontransfected cEC (up to 26% of total cell number). Seeding lacZ-transfected cEC on explanted arteries revealed rapid adhesion of the cells (within minutes) to the intact endothelium. After injection of 10(6) transfected EC via the femoral artery into the microvascular bed of the hind limb their presence was documented by beta-galactosidase staining after various time periods (1 h to 4 wk). Implanted cEC were detected in numerous elements of the microcirculation both in frozen sections and in squash preparations of the hind limb muscle and in the femoral bone up to 4 wk after the injection. The microvascular bed of skeletal muscle of the mouse as a recipient site for transduced syngeneic endothelial cells is, thus, a suitable experimental model to study various strategies for somatic gene therapy.