Hypothermic Perfusion Preservation of Pancreas for Islet Grafts: Validation Using a Split Lobe Porcine Model

Abstract

The demand for high-quality islets for transplantation in type I diabetics will increase as the current clinical trials transition into standard of care. The mode of preservation of donor pancreata is critical to this mission since islets are very sensitive to ischemic injury. Hypothermic perfusion preservation (HPP) is being investigated for extended pancreas preservation in light of the beneficial effects reported for other organs. The present pilot study aimed to establish the potency of porcine islets isolated from pancreata after 24 h of HPP at 4-8°C. The study design included a split-lobe pancreas model that permitted paired comparisons of islets isolated from 24-h HPP splenic lobes with nonperfused, fresh control duodenal/connecting lobes stored at 4°C for <3 h. Prior to transplantation, islet viability was assessed in vitro using the ratio of oxygen consumption rate to DNA (OCR/DNA) assay and correlated with subsequent in vivo function by transplantation in diabetic immunodeficient mice. The OCR/DNA (mean ± SD) measured after 7 days of culture and immediately prior to transplantation for islets from the 24-h HPP group was 269 ± 19 nmol/min/mg DNA, which was higher but not statistically different to the mean of 236 ± 43 for the counterpart control group. All four nude mice transplanted with islets from the 24-h HPP group showed diabetes reversal, compared with five of six transplants from the control group. In conclusion, islets isolated from adult porcine pancreata after 24-h HPP exhibited high viability as measured by OCR/DNA and were able to consistently reverse diabetes in a nude mouse bioassay.