Reconstitution of Human Corpus Cavernosum Smooth Muscle in Vitro and in Vivo

Abstract

A large number of congenital and acquired abnormalities of the genitalia would benefit from the availability of transplantable, autologous corpus cavernosum tissue for use in reconstructive procedures. We describe the results of preliminary experiments designed to determine the feasibility of using cultured human corporal smooth muscle cells seeded onto biodegradable polymer scaffolds for the formation of corpus cavernosum smooth muscle in vitro and in vivo. Primary cultures of human corpus cavernosum smooth muscle cells were derived from operative biopsies obtained during penile prosthesis implantation. Cells were characterized in vitro and seeded as a contiguous multilayered sheet onto polymers of non-woven polyglycolic acid. The seeded polymer constructs were then implanted subcutaneously in athymic mice. Animals were killed 7, 14, and 24 days after surgery and implants were examined via histology, immunocytochemistry, and Western blot analyses. Cultured cell multilayers were identified as smooth muscle before implantation via phase-contrast microscopy, immunocytochemistry and Western blot analyses. Retrieved implants from all time points demonstrated corporal smooth muscle tissue grossly, and histologically, at the time of sacrifice. Intact smooth muscle cell multilayers were observed growing along the surface of the polymers. There was evidence of early vascular ingrowth at the periphery of the implants by 7 days. By 24 days, there was evidence of polymer degradation. Maintenance of the smooth muscle phenotype in vivo was confirmed immunocytochemically and by Western blot analyses with antibodies to α-smooth muscle actin. This study provides evidence that cultured human corporal smooth muscle cells may be used in conjunction with biodegradable polymer scaffolds to create corpus cavernosum smooth muscle tissue in vitro and in vivo.