| Abstract: | Human islets of Langerhans were isolated from the pancreata of 13 adult organ donors, cultured for 24 h, cryopreserved, stored in liquid nitrogen at -196 degrees C for 6-88 days, thawed, and then cultured again. The number of islets recovered after this procedure was 80% of that present at the beginning. The viability of cultured/cryopreserved islets was then compared with that of islets from the same donor cultured for 24 hr, and was assessed by supravital staining, insulin response to glucose, and survival after implantation under the kidney capsule of nude rats. Supravital staining showed more nonviable cells in cryopreserved islets than in their cultured counterparts. Significant response to glucose was seen before and after cryopreservation in 2 of 4 sets of islets. Xenografts of 200 cultured islets (from 13 donors) were implanted in 15 nude rats under the kidney capsule, and a further 15 rats had cryopreserved islets (from the same 13 donors) similarly implanted beneath the kidney capsule. Two weeks later tissue was visible at the site of implantation in all 30 rats. Histological examination of both groups showed the tissue to have the morphology of islets, confirmed by immunohistochemical chemical localization of insulin. The insulin content of kidneys bearing 200 cultured islets was 7.88 +/- 1.6 mU (n = 13) versus 6.84 +/- 1.43 mU (n = 13) for kidneys bearing cryopreserved islets. Thus this technique for cryopreservation of isolated adult human islets enables a high recovery of endocrine tissue that survives after transplantation to nude rats, but some evidence of damage was apparent from insulin secretion studies and electron-microscopic studies. |
