Improved human pancreatic islet purification with the refined UIC-UB density gradient

Human islet isolation outcomes were compared between two purification methods; 32 pancreases were processed by conventional Biocoll purification method (SM, standard method) and 132 pancreases by a refined University of Illinois at Chicago UW/Biocoll method (UIC-UB). There was no difference in donor characteristics between the two study groups. The prepurification equivalent islet number was similar between the groups (359,425 40,794 equivalent islet number in SM vs. 370,682 17,579 in UIC-UB). SM purified islets were mostly collected in only 2 of 12 fractions (68.9% and 36.3% purity). With the UIC-UB, highly purified islets were collected in 6 of 12 separate fractions (fractions 3-8 with purity of 84.8%, 82.5%, 72.0%, 59.3%, 46.8%, and 36.2%). UIC-UB yielded significantly greater islet yield compared with SM (368,419 +/- 18,245 vs. 260,908 +/- 37,835, P = 0.017). Islet recovery rate was superior in UIC-UB (84.9% vs. 64.5%, P = 0.04). Our study demonstrates a superior recovery of highly pure human pancreatic islets after purification using the refined method of UIC-UB gradient.