Omental roll-up: a technique for islet engraftment in a large animal model.

ABSTRACT

BACKGROUND: Attrition of transplanted islets is significant after hepatic embolization. This study was designed to investigate a novel surgical technique for islet transplantation into the omentum. This site allows placement of the islets in a three-dimensional (3D) matrix, with growth factors, to temporarily culture the islets in vivo while revascularization progresses. MATERIALS AND METHODS: Five female dogs (three partial and two total pancreatectomies) received an autologous islet transplant in the omentum. Islets were suspended in 1 mL of PBS containing 10 ug of vascular endothelial growth factor (VEGF). Fresh autologous plasma (10 mL) was mixed with the islet/VEGF suspension. The coagulum containing the islets and VEGF was then placed on the greater omentum. The leading edge of omentum was rolled up to secure the islet/VEGF/coagulum in position and to present the thin islet layer with two omental surfaces for implantation. Omentum was recovered at 2, 13, 21, 42, and 180 d. RESULTS: Immunohistochemical staining for synaptophysin, glucagon, and insulin confirmed the presence of transplanted islets in all omenta. Insulin and C peptide production from the omental islets was confirmed in portal venous samples, and normalization of morning glucose levels beginning on day 7 was seen in the total pancreatectomy experiment. CONCLUSIONS: Autologous islets implant in rolled-up omentum when placed as a VEGF/autologous plasma coagulum. This technique has potential benefits, including the opportunity to accelerate revascularization and to investigate local strategies for modulating the immune response.