Long‐term culture, low‐temperature culture, and hyperoxic culture do not prolong fish‐to‐mouse islet xenograft survival

Abstract

Abstract: Macroscopic, anatomically discrete islets called Brockmann bodies (BB) were harvested from tilapia with microscissors and then cultured under various conditions known to prolong islet allograft survival. BBs were cultured in 95% air/5% CO2 at 37°C either overnight (groups 1 and 2) or for 1 week (group 3); in 95% O2/5% CO2 at 37°C for 1 week (group 4), or in 95% air/5% CO2 at 24°C for 1 week (groups 5 and 6). Viability and function of cultured islets was confirmed by fluorescein diacetate/ethidium bromide staining and by transplantation under the left renal capsules of streptozotocin‐diabetic balb/c mice. Recipient mice in groups 2 and 6 received CsA (50 mg/kg/d p.o.) × 4 days. All recipient mice became normoglycemic posttransplant. Mean graft survival times (± S.D.) for groups 1, 2, 3, 4, 5, and 6 were 7.6 (± 1.1), 6.2 (± 1.5), 6.4 (± 0.79), 8.2 (± 2.3), 7.0 (± 0.71), and 6.2 (± 0.45) days, respectively. Rejection (i.e., nonfasting plasma glucose levels > 200 mg/dl) was confirmed histologically in all instances; rejection was characterized by infiltrates composed of mononuclear cells, plasma cells, and eosinophils. In our study, neither short‐term CsA nor any of the culture protocols significantly prolonged discordant fish‐to‐mouse islet xenograft survival.