Baylor Research Institute, Dallas, TX, USA.
Cell Transplant. 2012;21(7):1361-70. doi: 10.3727/096368912X637514.
One of the major issues in clinical islet transplantation is the poor efficacy of islet isolation. During pancreas preservation and islet isolation, islets suffer from hypoxia as islets are highly sensitive to hypoxic conditions.Cold preservation has been applied to minimize hypoxia-induced cell damage during organ preservation.However, the studies related to hypoxia-induced islet cell damage during islet isolation are limited. Recently,we demonstrated that mouse islets contain high levels of high-mobility group box 1 protein (HMGB1), and during proinflammatory cytokine-induced damage, islets release HMGB1 outside the cell. The released HMGB1 is involved in the initial events of early islet loss. In the present study, we hypothesize that low temperature conditions could prevent both hypoxia induced islet cell damage and HMGB1 release from islets in a mouse model. Isolated mouse islets underwent normoxic condition (95% air and 5% CO(2)) at 37°C or hypoxic conditions (1% O(2), 5% CO(2), and 94% N(2)) at 37°C (hypoxia-37°C islets), 22°C (hypoxia-22°C islets), or 4°C (hypoxia-4°C islets) for 12 h. In vitro and in vivo viability and functionality tests were performed. HMGB1, IL-6, G-CSF, KC, RANTES, MCP-1, and MIP-1α levels in the medium were measured. Low temperature conditions substantially reduced hypoxia-induced necrosis (p < 0.05) and apoptosis (p < 0.05). In addition, low temperature islet culture significantly increased the insulin secretion from islets by high glucose stimulation (p < 0.05). All of the recipient mice reversed diabetes after receiving the hypoxia-4°C islets but not after receipt of hypoxia-37°C or 22°C islets. The amounts of released HMGB1, IL-6, G-CSF, KC, RANTES, MCP-1, and MIP-1α were significantly reduced in the hypoxia-4°C islets compared to those of the hypoxia-37°C islets (p < 0.05). In conclusion, low temperature conditions could prevent hypoxia-induced islet cell damage, inflammatory reactions in islets, and HMGB1 release and expression. Low temperature conditions should improve the efficacy of isolated islets.
临床胰岛移植的主要问题之一是胰岛分离效果不佳。在胰腺保存和胰岛分离过程中，胰岛会遭受缺氧，因为胰岛对缺氧环境非常敏感。低温保存已被应用于最小化器官保存过程中缺氧引起的细胞损伤。然而，关于胰岛分离过程中缺氧诱导的胰岛细胞损伤的研究有限。最近，我们证明了小鼠胰岛中含有高水平的高迁移率族蛋白 B1（HMGB1），并且在促炎细胞因子诱导的损伤过程中，胰岛会将 HMGB1 释放到细胞外。释放的 HMGB1 参与了早期胰岛丢失的初始事件。在本研究中，我们假设低温条件可以防止在小鼠模型中缺氧诱导的胰岛细胞损伤和 HMGB1 从胰岛中的释放。分离的小鼠胰岛在 37°C 下处于常氧条件（95%空气和 5%CO(2)) 或在 37°C 下处于缺氧条件（1%O(2)、5%CO(2)和 94%N(2)) （缺氧-37°C 胰岛）、22°C（缺氧-22°C 胰岛）或 4°C（缺氧-4°C 胰岛）下孵育 12 小时。进行了体外和体内活力和功能测试。测量了培养基中 HMGB1、IL-6、G-CSF、KC、RANTES、MCP-1 和 MIP-1α 的水平。低温条件显著降低了缺氧诱导的坏死（p < 0.05）和凋亡（p < 0.05）。此外，低温胰岛培养显著增加了高糖刺激下胰岛的胰岛素分泌（p < 0.05）。所有接受缺氧-4°C 胰岛的受体小鼠在接受后逆转了糖尿病，但接受缺氧-37°C 或 22°C 胰岛后没有逆转。与缺氧-37°C 胰岛相比，缺氧-4°C 胰岛中释放的 HMGB1、IL-6、G-CSF、KC、RANTES、MCP-1 和 MIP-1α 的量显著减少（p < 0.05）。总之，低温条件可以防止缺氧诱导的胰岛细胞损伤、胰岛中的炎症反应和 HMGB1 的释放和表达。低温条件应提高分离胰岛的功效。
