Saline Contamination of University of Wisconsin Solution Preserved Human Pancreata

Abstract

The use of University of Wisconsin (UW) solution is widely accepted for the cold storage and transport of human donor pancreata destined for islet isolation. While several variables exist in islet isolation, proper procurement and packaging is essential for optimizing preprocessing conditions. This study examined the effect of normal saline (NS) contamination/dilution of transport UW solution in 89 human pancreata processed by our islet isolation program. Samples of UW were taken from the primary pancreas container and examined for the presence of blood and or hemolysis. The cold ischemia time (CIT) was calculated, and processing by cold collagenase perfusion commenced. Islets were then isolated by collagenase digestion, purified by continuous gradient Ficoll centrifugation, and islet equivalent (IE) yield determined by dithizone staining. Viability of isolated islets was assayed by using the fluorescent SYTO/ethidium bromide (SYTO/EB) method. Na⁺ and K⁺ values were assayed using ion-specific electrode methodologies. Isolation outcomes were grouped by successful versus unsuccessful categories, and statistically compared using an unpaired t-test, where p < 0.05 was deemed to be statistically significant. Values are expressed as mean ± SEM. There was no significant relationship between increased Na⁺ and an unsuccessful isolation as a single variable. The study did suggest that the prolonged ischemic pancreas is more vulnerable to isolation failure if significant Na⁺ is present. In either case, a shorter CIT in UW was beneficial to increased IE yield and viability in human islet isolation.