Using HTK for prolonged pancreas preservation prior to human islet isolation

Histidine-tryptophan-ketoglutarate (HTK) has been established as an alternative to University-of-Wisconsin solution (UWS) for abdominal organ preservation, but data about HTK efficiency to preserve pancreata during prolonged cold ischemia time (CIT) are conflicting. In human islet transplantation, HTK provided similar isolation outcomes after short CIT. The present study aimed to investigate whether islets can be successfully isolated from HTK-preserved pancreata after prolonged CIT compared with UWS.

Sixty-four human pancreata retrieved from donors meeting criteria for kidney donation were perfused utilizing either HTK or UWS and preserved for more or less than 10 h prior to islet isolation. Along with parameters related to isolation and islet quality assessment, the dry-to-wet weight ratio was evaluated.

Donor- and procurement-related factors did not vary between HTK- and UWS-perfused pancreata. The dry-to-wet weight ratio was lower in HTK-preserved pancreata indicated tissue edema (21.0% ± 3.5% versus 24.8% ± 2.0%, P = 0.007). Isolation-related variables differed between experimental groups after prolonged CIT with respect to purified packed tissue volume (9.1 ± 5.0 versus 17.2 ± 8.1 μL/g, P = 0.004) and islet yield (1910 ± 980 versus 3150 ± 1420 IE/g, P = 0.012). Islet purity and survival after culture were similar after HTK or UWS perfusion. The preservation solution did not affect in vitro function and transplantability of isolated islets.

Compared with UWS, HTK has similar efficiency to preserve human pancreata for subsequent islet isolation during <10 h CIT but seems to be limited for prolonged cold storage.