Histidine-Tryptophan-Ketoglutarate and University of Wisconsin Solution Demonstrate Equal Effectiveness in the Preservation of Human Pancreata Intended for Islet Isolation: A Large-Scale, Single-Center Experience

We previously reported a small-scale study on the efficacy of histidine-tryptophan-ketoglutarate (HTK) solution versus University of Wisconsin (UW) solution on pancreas preservation for islet isolation. In this large-scale, retrospective analysis (n=252), we extend our initial description of the impact of HTK on islet isolation outcomes and include pancreatic digestion efficacy, purification outcomes, and islet size distribution. Multivariable linear regression analysis, adjusted for donor age, sex, BMI, cold ischemia time, and enzyme, demonstrated similar results for the HTK group (n=95) and the UW group (n=157), including postpurification islet yields (HTK: 289,702 IEQ vs. UW: 283,036 IEQ; p=0.76), percentage of digested pancreatic tissue (HTK: 66.9% vs. UW: 64.1%; p=0.18), and islet loss from postdigestion to postpurification (HTK: 24,972 IEQ vs. MAT: 39,551 IEQ; p=0.38). Changes in islet size between the postdigestion and postpurification stages were comparable within each islet size category for HTK and UW (p=0.14-0.99). Tissue volume distribution across purification fractions and islet purity in the top fractions were similar between the groups; however, the HTK group had significantly higher islet purity in the middle fractions (p=0.003-0.008). Islet viability and stimulation indices were also similar between the HTK and the UW groups. In addition, we analyzed a small sample of patients transplanted either with HTK (n=7) or UW (n=8) preserved islets and found no significant differences in posttransplant HbA(1e), beta-score, and frequency of insulin independence. This study demonstrates that HTK and UW solutions offer comparable pancreas preservation for islet transplantation. More in vivo islet outcome data are needed for a complete analysis of the effects of HTK on islet transplantation.