Islet Isolation from the Pancreas of Large Mammals and Humans: 10 Years of Experience

Abstract

Despite experience, that has been obtained in the field of islet isolation in large mammals for about the past 20 years, allo- and autotransplantation of both human and porcine islets are still not routine procedures. The reasons for islet isolation and purification associated problems, which prevent a continuous isolation success and regular islet transplantation, can be categorized to variables related to 1) pancreas donor; 2) pancreas procurement; 3) isolation-techniques and 4) purification techniques. The development of porcine and human islet isolation was carried out by the authors since 1986. During this period several techniques for the isolation and purification of human and porcine islets were compared with regard to their influence on islet isolation outcome, integrity of islet morphology, islet in-vitro and in-vivo function: sequential vs continuous digestion-filtration, counterflow elutriation vs neutral density separation, conventional density gradient centrifugation vs Cobe cell separation and discontinuous vs continuous gradient purification. Furthermore, we analysed the influence of donor factors and variables related to organ procurement on islet isolation success. From this experience we concluded that successful porcine islet isolation is possible if islets of adult donors are isolated utilizing the continuous digestion-filtration following distension with UW-solution prior to a neutral density gradient purification on a Cobe. Human islets can be successfully isolated by digestion-filtration and purified utilizing a continuous Ficoll-sodium-diatrizoate gradient on a Cobe when intact pancreata are harvested after a secondary pancreatic warm ischemia time < 20 min from adult donors > 30 years.

Comparative aspects of rodent and nonrodent animal models for mechanistic and translational diabetes research

“…In contrast, the capsule in human and especially pig islets is more diffuse or even absent, making them more prone to injury during isolation with collagenase digestion [95]. Rodent islets have a roundto-oval shape, whereas human and pig islets are predominantly irregularly shaped [121]. Fractional volumes of the different endocrine cell populations within the islet differ slightly by species (Table 2), with the most prominent difference in human neonates showing a distinctly lower beta-to-alpha cell ratio compared to adults and animal species [97].…”

Sustained insulin secretory response in human islets co-cultured with pancreatic duct-derived epithelial cells within a rotational cell culture system

“…Disruption of the complex cytoarchitecture of the human islet as a consequence of isolation leads to a loss of both structural and functional integrity [3][4][5], and pretransplant culture is associated with a decline in beta cell mass [6,7] concomitant with a marked diminution in glucose sensitivity [8,9]. The adverse events occurring within the islet during the early post-isolation period also narrow the 'window of opportunity' for their use in research and drug development.…”

Islet xenotransplantation: what is the optimal age of the islet‐source pig?

“…As expected, the average yield of islets is considerably higher from adult pigs than from neonatal and fetal pigs (Table 1) [63,64]. Even though retired breeders (>2 yr old and in excess of 200 kg) more consistently provide a higher yield and also of compact and spherical morphology [65], the isolation of adult pig islets remains technically challenging and expensive [42,[66][67][68]. It is an arduous process that requires cannulation of the pancreatic duct, perfusion of the organ with warm enzymes, and controlled and balanced enzymatic digestion of the pancreas.…”