Acute insulin response of donors is correlated with pancreatic islet isolation outcome in the pig

Abstract

Aims/hypothesis: Unpredictability of islet isolation outcome remains a frustrating and costly issue in the clinical implementation of islet transplantation. The aim of this experimental study was to test the hypothesis that the donor's insulin secretory reserve, an in vivo surrogate of functional pancreatic mass, is correlated with the outcome of islet isolation. Methods: Insulin secretory reserve was evaluated in 28 healthy adult minipigs prior to pancreatectomy and islet isolation. Blood glucose and insulinaemia were measured before and 1, 3, 5, 10, 15, 30, 60 and 90 min after glucose infusion. Following total pancreatectomy, islet isolation was performed according to Ricordi's semi-automated method, and the total number of islets obtained was determined. Fasting blood glucose, insulinaemia, acute insulin response (AIR), maximal insulinaemia and the glucose decay constant (K G ) were calculated, and possible associations with the outcome of islet isolation were assessed. Results: AIR and maximal insulinaemia after glucose injection were correlated with the outcome of islet isolation (p<0.01). Mean values for AIR and maximal insulinaemia were significantly different between animals in which islet isolation was successful (n=11) vs those in which it was unsuccessful (n=17) (77.6±13.7 μU/ml vs 42.3±7.8 μU/ml, p<0.05; 144.7± 21.6 μU/ml vs 71.9±10.4 μU/ml, p<0.05, respectively). Conclusions/interpretation: This study suggests that the donor's pancreatic endocrine mass, as estimated by AIR, is a major determinant of the outcome of islet isolation in large mammals. Our results may explain the frustrating variability of human islet isolation outcome and could lead to a new approach for optimising the selection of brain-dead and/or living pancreas donors.

Influence of Preservation Solution on Human Islet Isolation Outcome

“…Total pancreatectomy was performed as previously described for limiting warm ischemia (6,33): an adequate volume of either Celsior (nϭ5), UW (nϭ4), or Solution de Conservation d'Organes et de Tissus (SCOT, Macopharma, Mouvaux, France) (nϭ5) solution was perfused through a catheter inserted in the aorta for in situ perfusion of all abdominal organs including pancreas with the preservation solution. Simultaneous to clamping the aorta, ice packs were quickly poured into the abdominal cavity for lowering the temperature within the abdominal cavity at 4°C.…”

“…Optimizing the use of the scarce available organs and limited human and financial resources by increasing the consistency of the procedure appears therefore essential (5). Despite several technical improvements in the isolation method, the donor characteristics still condition the outcome of islet isolation (6). A stringent donor selection according to age and body mass index is therefore proposed by some authors (7).…”

Predicting the outcome of islet isolation in large mammals

“…Exploring this hypothesis in large mammalian models, we indeed confirmed that the main determinant of islet isolation outcome is the donor islet mass itself. In two studies, in the pig [5] and in humans [6], the pancreatic endocrine mass was assessed by determination of the acute insulin response (AIR) [7] in the donor. Stimulation by injection of arginine is preferred in human organ donors because it does not affect glycaemia and does not interfere with the functioning of other organs, whereas glucose can be used as an alternative in experimental studies, as employed in our pig model [5].…”

Pre‐clinical model of composite foetal pig pancreas fragment/renal xenotransplantation to treat renal failure and diabetes

“…It is well known that one of the major difficulties associated with using adult pigs for islet isolation is the need for these donor animals to be more than 2 yr of age to have developed enough fibrous capsule around the islet to prevent it being broken down during pancreas digestion [17]. Even when purpose bred pigs have been developed for the express purpose of improved islet isolation, there remains the logistical difficulties of keeping and handling large numbers of adult donor pigs in specialized pathogen‐free housing for extended periods of time, making it extremely expensive and rather impractical [18].…”