Department of Surgery, University of California Irvine, Orange, CA, USA.
Department of Surgery, University of California Irvine, Orange, CA, USA; Department of Biomedical Engineering, University of California Irvine, Irvine, CA, USA.
Cryobiology. 2019 Jun;88:23-28. doi: 10.1016/j.cryobiol.2019.04.004. Epub 2019 Apr 13.
Islet transplantation has been shown to restore normoglycemia in animal models and for type 1 diabetic patients in clinical trials. One method of storing islets intended for transplantation is via cryobanking at very low temperatures (-196 °C). Cryobanking islets without the use of cryoprotecting agents (CPAs) contributes to cellular shear stress and cell death. Although current CPA protocols vary, high concentrations of these agents are toxic to islets cells. This study tested the effects of the permeating CPA dimethyl sulfoxide (MeSO) with the addition of ethylene glycol (EG), both at reduced concentrations, on rat and human islet cell yield, viability, and glucose stimulated insulin release (GSIR). To test this, islets were treated using three combinations of CPAs (2M MESO, 1M MESO + 1M EG, and 1M MESO + 0.5M EG). Next, fresh islets, 2M MESO islets, and 1M MESO + 0.5M EG isolated rat islets were transplanted into streptozotocin-induced (STZ) diabetic mice. Our data showed that cryopreservation with a reduced concentration of MESO (1M MESO + multimolar EG) achieved a higher percent yield and viability when compared to the current standard 2M MESO treatment for both rat and human islets. Furthermore, STZ-induced diabetic mice achieved normoglycemia after transplantation with 1000 islet equivalents (IE), an average 12 days sooner, with islets cryopreserved with reduced-concentration (MESO + 0.5M EG), compared to islets preserved with 2M MESO. In conclusion, reduced concentration of penetrating CPAs during islet cryopreservation increases islet yield and viability in vitro and reduces delay before normoglycemia in diabetic mice.
胰岛移植已被证明可在动物模型中恢复正常血糖水平，并可在临床试验中用于 1 型糖尿病患者。一种用于移植的胰岛储存方法是通过在非常低的温度（-196°C）下进行低温保存。不使用冷冻保护剂（CPAs）的低温保存会导致细胞剪切应力和细胞死亡。尽管目前的 CPA 方案有所不同，但这些试剂的高浓度对胰岛细胞有毒。本研究测试了低浓度渗透 CPA 二甲亚砜（MeSO）与乙二醇（EG）的添加对大鼠和人胰岛细胞产量、活力和葡萄糖刺激胰岛素释放（GSIR）的影响。为此，使用三种 CPA 组合（2M MeSO、1M MeSO+1M EG 和 1M MeSO+0.5M EG）处理胰岛。接下来，将新鲜胰岛、2M MeSO 胰岛和 1M MeSO+0.5M EG 分离的大鼠胰岛移植到链脲佐菌素（STZ）诱导的糖尿病小鼠中。我们的数据表明，与当前的标准 2M MeSO 处理相比，用低浓度 MeSO（1M MeSO+多摩尔 EG）冷冻保存可获得更高的产率和活力，无论是大鼠还是人胰岛。此外，与用 2M MeSO 保存的胰岛相比，用低浓度（MeSO+0.5M EG）冷冻保存的胰岛移植后，STZ 诱导的糖尿病小鼠在 1000 个胰岛当量（IE）时达到正常血糖水平的时间平均提前了 12 天。总之，在胰岛冷冻保存过程中降低渗透 CPA 的浓度可提高体外胰岛的产量和活力，并减少糖尿病小鼠达到正常血糖水平的延迟。
