Freezing: A Tool for the Preservation and Separation of Islets of Langerhans

Abstract

Many forms of diabetes can be successfully treated by oral hypoglycemic drugs or by subcutaneous administration of insulin or insulin analogs. A major disadvantage of such treatment is the difficulty in adjusting the insulin dose (hence blood glucose levels) in response to food consumption. The ideal therapy would utilize a continuous feedback network which permits minute by minute surveillance of the blood glucose level with appropriate alteration of hormonal output, just as the alpha and beta cells of the islets respond in the normal individual. One approach is to reimplant islets or beta cells in patients whose islets of Langerhans are not responding at an adequate level (Lacy, 1967, 1980; Mattas, 1976, 1977). The probability of a successful transplant would be greatly enhanced if large numbers of tissue-typed islets could be cryogenically stored until an immunologically suitable diabetic recipient is available. Since viability of frozen tissue stored in liquid nitrogen is essentially independent of the storage time, the current constraints involved in obtaining good tissue cross-matches can be overcome. Reimplantation of nonimmunogenic islets of Langerhans will provide the minute by minute regulation of blood glucose levels necessary to prevent the peripheral vascular complications of insulin dependent diabetes, including diabetic retinopathy, clotting disorders and glomerular nephritis.