New Method of Cryopreservation for Pancreatic Islets by Flash Freeze Apparatus

自2004年以来，日本对胰岛素依赖型糖尿病(IDDM)患者进行了胰岛移植。然而，这种治疗方法尚未普及，因为用于胰岛移植的供体一直很少。如果不能从供体胰腺中分离出足够数量的胰岛，我们就不能移植胰岛。在这种情况下，我们应该对胰岛进行冷冻保存，以便在未来的移植机会中使用。胰岛的冷冻保存是近几年发展起来的。然而，胰岛解冻后的功能和复苏率并不完全令人满意。需要更多的研究才能应用于临床治疗。在本研究中，我们寻求一种更好的胰岛冷冻保存方法的解决方案。我们与昭和丹参株式会社的胰岛保存团队共同开发了一种新的胰岛冷冻保存设备。该装置通过胰岛颗粒和液氮的混合，在瞬间将胰岛颗粒均匀制成冰冻颗粒。因此，冷冻胰岛被认为是为了保持胰岛解冻后的结构和分泌功能。利用该装置可以连续制备直径为0.5 mm的CP-1/RPMI1640冻结液冷冻颗粒，并获得80%的颗粒收集率。然而，使用胰岛胶体溶液时，冷冻颗粒没有得到充分的制备，冻结的胰岛颗粒不会被不便地从仪器中拯救出来。目前，该设备已被改进以克服这些问题。该设备将成为解决胰岛冷冻保存中几个问题的有力工具。

Pancreatic islet transplantation has been performed for the patients with insulin-dependent diabetes mellitus (IDDM) in Japan since 2004. However, the treatment has not yet been popular, because donor for islet transplantation has been very few. We are not able to transplant the islets if enough population of islet is not isolated from donor pancreas. In the case, we should do cryopreservation of islet for using it in future chance of transplantation. Cryopreservation of pancreatic islet has been developed in several years. However, function and recovery rate of islet after thawing are not fully satisfied. More studies are necessary to apply to clinical treatment. In this research, we searched for a solution of better cryopreservation methods for pancreatic islet.We developed a new apparatus for cryopreservation of pancreatic islet together with the Islet Preservation Team in Showa Tansan Co., LTD. The apparatus uniformly makes freeze particles of islet in a moment by mixing islet particles and liquid nitrogen. Consequently, freeze islets are thought to keep the structure and secretion function of islet after thawed out. With this apparatus, we were able to constantly prepare 0.5mm diameter freeze particles of CP-1/RPMI1640 freeze liquid and get the particles with 80% of collecting rate. However, with colloid solution of islets, freeze particles were not sufficiently made and the freeze islet particles were not inconveniently rescued from the apparatus. Now, the apparatus has been improved to overcome these problems.This apparatus would be a potent instrument for solution of several problems in cryopreservation of pancreatic islets.