Improved Islet Yields From Macaca Nemestrina and Marginal Human Pancreata After Two‐Layer Method Preservation and Endogenous Trypsin Inhibition

Abstract

We tested whether two‐layer method (TLM) pancreas preservation and trypsin inhibition (Pefabloc) during processing allows longer preservation while retaining or improving viable islet recovery. Non‐marginal primate (Macaca nemestrina) and marginal human (ischemic or preservation‐injured) pancreata were processed with a research‐oriented pan technique (Seattle method). Organs were processed upon arrival (± Pefabloc), or after TLM or University of Wisconsin solution (UW) preservation (+ Pefabloc). Islet yield, viability, and function were assessed.Pefabloc increased M. nemestrina islet yields from 9696 ± 1749 IE/g to 15 822 ± 1332 IE/g (p < 0.01). Two‐layer method preservation (< 6 h) further increased yields, to 23 769 ± 2773 IE/g (vs. + Pefabloc; p < 0.01). Similarly, Pefabloc increased marginal human islet yields from 2473 ± 472 IE/g to 4723 ± 1006 IE/g (p < 0.04). This increase was maintained after lengthy TLM preservation (> 30 h; 4801 ± 1066 IE/g).We also tested the applicability of TLM preservation (23.5 ± 3.2 h) to the processing of marginal human pancreata by the Edmonton/Immune Tolerance Network clinical protocol. Islet yield and function approached published results of pancreata processed 4.8 ± 0.8 h after organ recovery (p = 0.06).Pefabloc, and TLM vs. UW preservation, prolonged the tolerable interval between organ recovery and islet isolation. Islet yield, viability, and functionality improved from both marginal and nonmarginal pancreata. We tested whether two‐layer method (TLM) pancreas preservation and trypsin inhibition (Pefabloc) during processing allows longer preservation while retaining or improving viable islet recovery. Non‐marginal primate (Macaca nemestrina) and marginal human (ischemic or preservation‐injured) pancreata were processed with a research‐oriented pan technique (Seattle method). Organs were processed upon arrival (± Pefabloc), or after TLM or University of Wisconsin solution (UW) preservation (+ Pefabloc). Islet yield, viability, and function were assessed. Pefabloc increased M. nemestrina islet yields from 9696 ± 1749 IE/g to 15 822 ± 1332 IE/g (p < 0.01). Two‐layer method preservation (< 6 h) further increased yields, to 23 769 ± 2773 IE/g (vs. + Pefabloc; p < 0.01). Similarly, Pefabloc increased marginal human islet yields from 2473 ± 472 IE/g to 4723 ± 1006 IE/g (p < 0.04). This increase was maintained after lengthy TLM preservation (> 30 h; 4801 ± 1066 IE/g). We also tested the applicability of TLM preservation (23.5 ± 3.2 h) to the processing of marginal human pancreata by the Edmonton/Immune Tolerance Network clinical protocol. Islet yield and function approached published results of pancreata processed 4.8 ± 0.8 h after organ recovery (p = 0.06). Pefabloc, and TLM vs. UW preservation, prolonged the tolerable interval between organ recovery and islet isolation. Islet yield, viability, and functionality improved from both marginal and nonmarginal pancreata.