Figure 4. Preparing a site by prevascularization to improve engraftment.
Preimplantation of a material stimulates vascular enrichment (a). The islets can then be introduced into the preimplanted device (b) or the device can be removed to create a space left by the device that the islets can be introduced into (c). All of these approaches result in a space for the islets that has a greater vascular supply at the time of transplantation than an unprepared site.