Sertoli cells enhance formation of capillary-like structures in vitro

Sertoli cells isolated from the testis (referred to as extratesticular Sertoli cells) have been shown to facilitate allo- and xenogeneic cell transplantations. It appears likely that the ability of these cells to enhance the success of cell engraftment is due, in part, to the retention of their intratesticular functions of trophic support and immunoprotection. Sertoli cells also are involved in the regulation of angiogenesis in the testis, which may also contribute to enhanced cell engraftment success facilitated by extratesticular Sertoli cells. Because the maintenance of the cell's intratesticular angiogenic function has not yet been evaluated for extratesticular Sertoli cells, this study examined the cell's ability to enhance angiogenesis in vitro. Sertoli cell conditioned media were derived from isolated rat Sertoli cell cultures and used in a rat aortic model of induced angiogenesis, in endothelial and smooth muscle cell monocultures, and in endothelial smooth muscle cocultures. An angiogenic rat cytokine array identified angiogenic factors in the control and conditioned media. Aorta sections incubated with Sertoli cell conditioned media showed a marked increase in the formation of capillary-like structures when compared to controls. Likewise, endothelial cells incubated in conditioned media organized into capillary-like structures not observed when incubated in control media. In coculture, smooth muscle cells were associated with endothelial cell-derived capillary-like structures only when incubated in conditioned media. Cytokine arrays indicated the presence and a qualitative increase of specific angiogenic growth factors in Sertoli cell conditioned media not observed in control media. Results indicate that extratesticular Sertoli cells retain their intratesticular angiogenic function in vitro.