Pancreatic islet cell survival following islet isolation: the role of cellular interactions in the pancreas

Abstract

The purpose of this study was to characterize the trophic effect of pancreatic duct cells on the islets of Langerhans. Ductal epithelium and islets were isolated from hamster pancreata. In addition, duct-conditioned medium (DCM) was prepared from primary duct cultures that had been passaged twice to remove other cellular elements. Three experimental groups were then established: Group 1, 100 islets alone; Group 2, 100 islets+80 duct fragments; and Group 3, 100 islets in 25% DCM. All tissues were embedded in rat tail collagen for up to 12 days and the influence of pancreatic ductal epithelium on islet cell survival was examined. By day 12, 20·6 3·0% (...) of the islets cultured alone developed central necrosis, compared with 6·7 2·0% of the islets co-cultured with ducts and 5·6 1·5% of the islets cultured in DCM (P<0·05). The presence of apoptotic cell death was determined by a TdT-mediated dUTP-biotin nick end labelling (TUNEL) assay and by a specific cell death ELISA. DNA fragmentation in islets cultured alone was significantly increased compared with islets cultured either in the presence of duct epithelium or in DCM (P<0·05). More than 80% of TUNEL-positive cells were situated in the inner 80% of the islet area, suggesting that most were -cells. DCM was analysed for known growth factors. The presence of a large amount of IGF-II (34 ng/ml) and a much smaller quantity of nerve growth factor (4 ng/ml) was identified. When the apoptosis studies were repeated to compare islets alone, islets+DCM and islets+IGF-II, the cell death ELISA indicated that IGF-II produced the same beneficial result as DCM when compared with islets cultured alone.We conclude that pancreatic ductal epithelium promotes islet cell survival. This effect appears to be mediated in a paracrine manner by the release of IGF-II from cells in the ductal epithelium.

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

“…Surrounding acinar and ductal cells are considered to be the source of important islet growth and regulatory factors, and the loss of their influences following islet isolation and culture may result in disordered beta cell function [18,19]. In the present investigation we sought to determine whether appropriate glucose signalling and insulin secretion could be restored in culture by re-establishing cellular interactions between islets and non-endocrine components of the human pancreas.…”

“…In the present investigation we sought to determine whether appropriate glucose signalling and insulin secretion could be restored in culture by re-establishing cellular interactions between islets and non-endocrine components of the human pancreas. Specifically, we aimed to re-introduce the influences exerted by pancreatic ductal epithelial cells (DECs), which are considered to be a potential source of trophic factors [19], ECM components [20] and beta cell progenitors [21] thought to contribute to sustained graft survival following islet transplantation [22].…”

Adenoviral overproduction of interleukin-1 receptor antagonist increases beta cell replication and mass in syngeneically transplanted islets, and improves metabolic outcome

“…Many factors play a role in early beta cell damage and death after transplantation, including islet injury during isolation [4,5], technical problems in the transplantation process [6], inadequate mass of islet tissue [7], hypoxia [8], exposure to the recipient hyperglycaemia [9], absence of survival factors present in the non-endocrine pancreas [10], or disruption of islet cellular connections to extracellular matrix [11]. In addition, non-specific inflammation at the grafted site, involving the expression of pro-inflammatory cytokines, is considered to play a role in early graft failure [4,5,12,13].…”

Co-encapsulation of bioengineered IGF-II-producing cells and pancreatic islets: effect on beta-cell survival

“…The culture medium was changed every second day as previously described. 5 Note that, for in vivo experiments, the time in culture (in CMRL) was limited to 2 days, the islets being transplanted 24 h after encapsulation and 48 h after isolation, which corresponds to what would be done in clinical applications. TM4-IGF-II and TM4-GFP cells were cultured in DMEM/F12 supplemented by serum until co-encapsulation with islets, then cultured for 24 h in CMRL until transplantation.…”

“…5 We have investigated the use of IGF-II in a transplantation setting. 6 In vitro studies showed that IGF-II prevents the apoptosis and necrosis of microencapsulated mouse islet cells in a dose-dependent manner.…”