Development of effective methods of islet transplantation for severe diabetes mellitus.

1.从刘易斯大鼠分离胰岛，经皮下组织（SCT）、肝门静脉或肾包膜下间隙（SNCS）移植至同系大鼠。移植后4周，胰岛素染色显示肝脏和SNCS中有存活的胰岛，但SCT中没有。正常大鼠胰腺，胰岛分离后立即，和移植的胰岛无论是在肝脏或SNCS免疫染色后胰蛋白酶处理的血管内皮生长因子（VEGF）。正常胰腺中的胰岛和分离后即刻的胰岛呈阳性染色，但移植（Tx）部位的胰岛倾向于VEGF阴性。另一方面，微波处理后的VEGF染色显示阳性结果，即使在胰岛的Tx网站，表明VEGF仍然存在后Tx。血管标记物，因子VIII相关抗原（vWF）和新生血管特异性标记物，血小板内皮细胞粘附分子-1（PECAM-1/CD-31）进行了类似的免疫染色。PECAM-1在正常胰岛中不表达，而在移植部位表达阳性，而vWF在正常和移植胰岛中表达阳性.在胰岛移植链脲佐菌素（STZ）糖尿病大鼠中检查了抗新生血管形成剂TNP-470的作用。TNP-470的给药不改变进食状态或口服葡萄糖耐量试验期间的血糖水平。然而，它取消了响应于口服葡萄糖激发的血浆胰岛素增加，这在正常大鼠和胰岛移植STZ大鼠中观察到，而没有TNP-470治疗。组织学检查显示血管样管状结构，缺乏PECAM-1阳性内皮层。这些结果表明，新血管可以从移植胰岛中诱发，并且促血管生成治疗可以改善移植胰岛的功能。

1. Islets of Langerhans were isolated from Lewis rats and transplanted to the same descent rats at either subcutaneous tissue (SCT), liver via the portal vein or subnephrocapsular space (SNCS). Up to 4 weeks after transplantation, insulin staining showed viable islets at the liver and SNCS but not at SCT.2. Normal rat pancreas, islets of Langerhans immediately after isolation, and transplanted islets either at the liver or SNCS were immunostained for vascular endothelial growth factor (VEGF) after trypsin treatment. Islets in the normal pancreas and immediately after isolation were positively stained but those at transplantation (Tx) sites tended to be VEGF-negative. On the other hand, VEGF-staining after microwave treatment showed positive results even in the islets at Tx sites, suggesting that VEGF still exists after Tx. A marker for blood vassels, factor VIII-related antigen (vWF), and specific marker for neogeneic vessels, platelet endothelial cell adhesion molecule-1 (PECAM-1/CD-31) were similarly immunostained. PECAM-1 was not stained in the islets of normal pancreas but became positively stained in those at Tx sites, whereas vWF was stained in normal and transplanted islets.3. Effects of an anti-neovascularization agent, TNP-470, were examined in islet-transplanted streptozotocin (STZ)-diabetic rats. Administered of TNP-470 did not altered blood glucose levels either at fed state or during oral glucose tolerance test. However, it abolished plasma insulin increase in response to oral glucose challenge, which was observed in normal rats and islet-transplanted STZ-rats without TNP-470 treatment. Histological examination revealed vessel-like tubular structures, which lack PECAM-1-positive endothelial layer.These results suggest that neovascularization can be evoked from transplanted islets and that neovascularization-promoting treatment may improve the function of transplanted islets.