A comparison of media supplement methods for the extended culture of human islet tissue
Fraga, D.W.; Sabek, O.; Hathaway, D.K.; Gaber, A.O.
Transplantation 65(8): 1060-1066
1998
ISSN/ISBN: 0041-1337 PMID: 9583866 Document Number: 491044
Background. The preservation of sufficient quantities of islets for human transplantation has proven to be a tenacious problem for researchers and transplant programs. Beyond the variables associated with islet procurement, there is the problem of tissue storage before transplantation. Cryopreservation has been adopted as a method for long-term islet storage that allows for recovery of viable tissue. However, there is significant tissue loss during the process and the possibility that long-term viability may be compromised. An alternate method of prolonged culture at 24degreeC was initially introduced as a means of reducing islet antigenicity. Although successful in the short term, prolonged culture with serum-based media has also resulted in a significant loss of tissue. In this study, we report the successful use of an ITS+ Premix-supplemented serum-free media for prolonged islet culture and its comparison to fetal bovine serum-supplemented media and to cryopreservation. Methods. Pancreata were procured from cadaveric organ donors, and islets were isolated using our own modification of the automated method of Ricordi. Aliquots from a series of human islet isolations were cultured in parallel in (A) CMRL + ITS (serum-free media; SFM) or (B) CMRL + 10% fetal bovine serum (standard media) and compared with cryopreserved and thawed tissue. Results. Our results show that SFM allows for the long-term culture of islet tissue. For time points up to 2 months, islets cultured in SFM showed recovery ratios greater than those for standard serum-supplemented media. At 1 week and 1 month, islet recovery ratios were greater for SFM-cultured islets than for cryopreserved tissue. Viability studies confirmed that the SFM-cultured islets were able to respond to glucose stimulation (stimulation index 0.8-21.2). Additionally, in vivo results using cultured islets in a patient demonstrated good islet function, with a 1-month stimulation index of 4.02 in response to an intravenous glucose tolerance test. Conclusion. We conclude that this culture modification represents a method by which functional islet tissue can be maintained in long-term culture and successfully transplanted.