Human islet function following 20 years of cryogenic biobanking.
OBJECTIVE
There are potential advantages to the low-temperature (-196 °C) banking of isolated islets, including the maintenance of viable islets for future research. We therefore assessed the in vitro and in vivo function of islets cryopreserved for nearly 20 years.


METHODS
Human islets were cryopreserved from 1991 to 2001 and thawed between 2012 and 2014. These were characterised by immunostaining, patch-clamp electrophysiology, insulin secretion, transcriptome analysis and transplantation into a streptozotocin (STZ)-induced mouse model of diabetes.


RESULTS
The cryopreservation time was 17.6 ± 0.4 years (n = 43). The thawed islets stained positive with dithizone, contained insulin-positive and glucagon-positive cells, and displayed levels of apoptosis and transcriptome profiles similar to those of freshly isolated islets, although their insulin content was lower. The cryopreserved beta cells possessed ion channels and exocytotic responses identical to those of freshly isolated beta cells. Cells from a subset of five donors demonstrated similar perifusion insulin secretion profiles pre- and post-cryopreservation. The transplantation of cryopreserved islets into the diabetic mice improved their glucose tolerance but did not completely normalise their blood glucose levels. Circulating human insulin and insulin-positive grafts were detectable at 10 weeks post-transplantation.


CONCLUSIONS
We have demonstrated the potential for long-term banking of human islets for research, which could enable the use of tissue from a large number of donors with future technologies to gain new insight into diabetes.
Alberta Diabetes Institute, University of Alberta, LKS Centre, Edmonton, AB, Canada, T6G 2R3.
Jocelyn E
JE
Manning Fox
James
J
Lyon
Xiao Qing
XQ
Dai
Robert C
RC
Wright
Julie
J
Hayward
Martijn
M
van de Bunt
Tatsuya
T
Kin
A M James
AM
Shapiro
Mark I
MI
McCarthy
Anna L
AL
Gloyn
Mark D
MD
Ungrin
Jonathan R
JR
Lakey
Norm M
NM
Kneteman
Garth L
GL
Warnock
Gregory S
GS
Korbutt
Raymond V
RV
Rajotte
Patrick E
PE
MacDonald
D000328:Adult; D000818:Animals; D015925:Cryopreservation; D003921:Diabetes Mellitus, Experimental / Q000628:therapy; D005089:Exocytosis / Q000502:physiology; D005260:Female; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000502:physiology; D007473:Ion Channels / Q000378:metabolism; D007515:Islets of Langerhans / Q000502:physiology*; D016381:Islets of Langerhans Transplantation; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018408:Patch-Clamp Techniques; D014015:Tissue Banks; D059467:Transcriptome / Q000235:genetics
D018398:Homeodomain Proteins; D007328:Insulin; D007473:Ion Channels; C064658:RAG-1 protein