Amelioration of streptozotocin-induced diabetes in mice using human islet cells derived from long-term culture in vitro1

Abstract

Long-term maintenance of the phenotype of β cells in vitro is difficult. The objective of this study was to examine an in vitro method for preserving the capacity of adult human β cells to express insulin. We evaluated the use of long-term cultured islet cells for the treatment of diabetic SCID mice.

Human islets were isolated from cadaveric donors. The islets were cultured as monolayers and clusters in repeating cycles for 4 months. Thereafter, the cells were tested in vitro for their capacity to express insulin and to secrete insulin in response to glucose challenge. Finally, the cluster-cultured cells were transplanted under the kidney capsule and into the kidney tissue in streptozotocin (STZ)-induced diabetic SCID mice.

Approximately 3.6% of cultured islet cells in cluster phase expressed insulin at 4 months and this was confirmed using immuno-gold-labeling electron microscopy. The cultured islet cells secreted insulin in response to glucose challenge in a dose-dependent manner. After transplantation, the islet cells redifferentiated and generated >20% insulin positive cells. The 4-month cultured cells rendered the blood glucose level near normal in mild diabetic mice (7.25 mM±1.595 vs. 15.225 mM±2.55, P <0.0025).

It is possible to preserve the capacity of adult human islets to express insulin over a 4-month period in vitro, and this capacity was enhanced significantly by transplantation into SCID mice. The described system will be useful in studies of β cell proliferation and differentiation.