Long-term storage methods, such as cryopreservation and long-term in vitro culture, hinder the therapeutical application of pancreatic islet transplantation, because they decrease islet viability. Pancreatic ductal epithelial cells ( @entity6567 ) are putative stem cells for islets, which may secrete specific factors supporting islet growth and function. Hence, we studied the effect of coculture with @entity6567 on the viability of fresh and cryopreserved @entity1 pancreatic islets. Islets and @entity6567 were isolated from the pancreas of an organ donor, and part of them were cryopreserved. Fresh and cryopreserved-thawed islets were cultured alone or in the presence of @entity6567 for 14 days at 33 degrees C or 37 degrees C. At day 1 and day 14 of culture, @entity2690 secretion was stimulated by two sequential 45-min exposures to low and high @entity413 concentrations (3.3 and 16.7 mmol/l, respectively). @entity2690 concentrations were measured by radio-immunoassay, and the ratio between the @entity2690 responses to high and low @entity413 was calculated ( @entity2690 stimulation index, ISI). After 14 days of culture, some fresh islets were processed for @entity4653 ( @entity4653 ). At day 14, ISI was markedly reduced in both fresh and cryopreserved islets with respect to 1 day cultures. Cryopreservation reduced ISI at day 1 and day 14, but in the latter case only when cultures were maintained at 37 degrees C. Coculture with @entity6567 did not affect ISI of fresh islets at day 1, and enhanced it at day 14, but only at a culture temperature of 33 degrees C. Conversely, coculture raised ISI of cryopreserved islets at both day 1 and day 14, independently of the culture temperature. @entity4653 showed that at day 14 of culture, the morphology of fresh islets displayed the best preservation when cocultured with @entity6567 at 33 degrees C. Our findings confirm that both long-term culture and cryopreservation decrease viability of @entity1 pancreatic islets. Moreover, they indicate that coculture of islets with @entity6567 at 33 degrees C represents a valuable tool to improve the survival and functional activity of islets, especially in the case of cryopreserved material.

Effects of cryopreservation and coculture with pancreatic ductal epithelial cells on XXXX secretion from @entity1 pancreatic islets.

@entity1 :: ('9606', 'Species') :: ['human'] @entity6567 :: ('CHEBI:23580', 'Chemical') :: ['DEC'] @entity2690 :: ('3630', 'Gene') :: ['Insulin', 'insulin'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose'] @entity4653 :: ('MESH:D004401', 'Disease') :: ['SEM', 'scanning electron microscopy']
@entity2690 :: (3630,Gene) :: ['insulin']
