Endothelial cell seeding of latissimus dorsi muscle pouches

The transformation of skeletal muscle tissue into a fatigue-resistant, autologous blood pump is being explored as an attempt to aid the failing heart. One of the options is to generate a pouch underneath the latissimus dorsi muscle, to connect an electrically conditioned muscle pouch to the circulation, and to use it as an autologous, contractile cardiac assist device. However, the potential of thrombus formation on the blood contacting surface, which is composed of fibrous material, might thwart the clinical usefulness of such skeletal muscle ventricles. We hypothesized that the thrombogenicity of these pouches could be reduced by lining their luminal surfaces with autologous endothelial cells. As a first step, we examined the feasibility of this approach under resting, nonbeating conditions. Using a multistage operative procedure, we isolated microvascular endothelial cells from canine adipose tissue and, after culturing these cells in the laboratory, seeded the autologous cells into preformed latissimus dorsi pouches in six mongrel dogs. Four to six weeks later the dogs were sacrificed and the ultrastructure of the pouches was examined by light and electron microscopy and by fluorescence techniques. The micrographs confirmed that the surfaces of seeded pouches, but not of the untreated controls, are lined with a continuous monolayer of functional endothelial cells, as assessed by the presence of several endothelial cell-specific markers. Current studies are under way to assess the thrombogenicity of these endothelialized skeletal muscle pouches.