The effect of pancreatic warm ischemia on islet isolation in rats and dogs

Abstract

Warm ischemia (WI) has been shown to be detrimental to organ function following transplantation. We investigated the effect of increasing warm ischemic time (WIT) on islet isolation in rats and dogs. Rat isolations were performed by collagenase digestion and Ficoll purification after increasing periods of WI. Dog isolations were performed after similarly increasing periods of WI by ductal perfusion with collagenase, counts being performed on unpurified tissue. Viability studies were performed on isolated purified rat islets by in vitro perifusion. Islet counts decreased as WIT increased such that after 45 min WI islet counts were only 45.7% of those at 0 WIT ( P < 0.001) in rats and 52.5% in dogs ( P < 0.002). Islet volumes decreased to 47.0% in rats ( P < 0.001) and 33.1% ( P < 0.001) in dogs over the same time period. After 90 min WIT islet counts were down to 15.6% ( P < 0.001) in rats and 23.9% in dogs ( P < 0.001) and volumes were down to 16.0% ( P < 0.001) in rats and 10.9% ( P < 0.001) in dogs. The increased release of insulin in response to dextrose stimulation was abolished after only 30 min WIT as assessed by perifusion. This work suggests that if successful islet isolation is to be performed for clinical transplantation, WI during donor pancreatectomy must be minimized, or techniques must be developed to prevent or reverse the ensuing effects.