Liraglutide, a long-acting human glucagon-like peptide 1 analogue, improves human islet survival in culture

The culture of human islets is associated with approximately 10-20% islet loss, occasionally preventing transplantation. Preconditioning of the islets to improve postculture yields would be of immediate benefit, with the potential to increase both the number of transplanted patients and their metabolic reserve. In this study, the effect of liraglutide, a long-acting human glucagon-like peptide 1 analogue, on cultured human islets was examined. Culture with liraglutide (1 micromol/l) was associated with a preservation of islet mass (significantly more islets at 24 and 48 h, compared to control; P ≤ 0.05 at 24 and 48 h) and with the presence of larger islets (P ≤ 0.05 at 48 h). These observations were supported by reduced apoptosis rates after 24 h of treatment. We also demonstrated that human islet engraftment is improved in C57Bl/6-RAG(-/-) mice treated with liraglutide 200 microg/kg sc twice daily (P ≤ 0.05), suggesting that liraglutide should be continued after transplantation. Overall, these data demonstrate the beneficial effect of liraglutide on cultured human islets, preserving islet mass. They support the design of clinical studies looking at the effect of liraglutide in clinical islet transplantation

Porcine marginal mass islet autografts resist metabolic failure over time and are enhanced by early treatment with liraglutide

Although insulin independence is maintained in most islet recipients at 1 yr after transplant, extended follow-up has revealed that many patients will eventually require insulin therapy. Previous studies have shown that islet autografts are prone to chronic failure in large animals and humans, suggesting that nonimmunological events contribute to islet graft functional decay. Early intervention with therapies that promote graft stability should provide a measurable benefit over time. In this study, the efficacy of the long-acting glucagon-like peptide-1 analog liraglutide was explored in a porcine marginal mass islet autograft transplant model. Incubation with liraglutide enhanced porcine islet survival and function after prolonged culture. Most vehicle-treated (83%) and liraglutide-treated (80%) animals became insulin independent after islet autotransplantation. Although liraglutide therapy did not improve insulin independence rates or blood glucose levels after transplant, a significant increase in insulin secretion and acute-phase insulin response was observed in treated animals. Surprisingly, no evidence for deterioration of graft function was observed in any of the transplanted animals over more than 18 months of follow-up despite significant weight gain; in fact, an enhanced response to glucose developed over time even in control animals. Histological analysis showed that intraportally transplanted islets remained highly insulin positive, retained alpha-cells, and did not form amyloid deposits. This study demonstrates that marginal mass porcine islet autografts have stable long-term function, even in the presence of an increasing metabolic demand. These results are discrepant with previous large animal studies and suggest that porcine islets may be resistant to metabolic failure

Human Islet Viability and Function Is Maintained During High-density Shipment in Silicone Rubber Membrane Vessels

BackgroundThe shipment of human islets (IE) from processing centers to distant laboratories is beneficial for both research and clinical applications. The maintenance of islet viability and function in transit is critically important. Gas-permeable silicone rubber membrane (SRM) vessels reduce the risk of hypoxia-induced death or dysfunction during high-density islet culture or shipment. SRM vessels may offer additional advantages: they are cost-effective (fewer flasks, less labor needed), safer (lower contamination risk), and simpler (culture vessel can also be used for shipment).MethodIE were isolated from two manufacturing centers and shipped in 10-cm(2) surface area SRM vessels in temperature- and pressure-controlled containers to a distant center after at least 2 days of culture (n = 6). Three conditions were examined: low density (LD), high density (HD), and a microcentrifuge tube negative control (NC). LD was designed to mimic the standard culture density for IE preparations (200 IE/cm(2)), while HD was designed to have a 20-fold higher tissue density, which would enable the culture of an entire human isolation in 1-3 vessels. Upon receipt, islets were assessed for viability (measured by oxygen consumption rate normalized to DNA content [OCR/DNA)]), quantity (measured by DNA), and, when possible, potency and function (measured by dynamic glucose-stimulated insulin secretion measurements and transplants in immunodeficient B6 Rag(+/-) mice). Postshipment OCR/DNA was not reduced in HD vs LD and was substantially reduced in the NC condition. HD islets exhibited normal function postshipment. Based on the data, we conclude that entire islet isolations (up to 400,000 IE) may be shipped using a single, larger SRM vessel with no negative effect on viability and ex vivo and in vivo function

Human Islet Viability and Function Is Maintained During High-density Shipment in Silicone Rubber Membrane Vessels

The shipment of human islets from processing centers to distant laboratories is beneficial for both research and clinical applications. The maintenance of islet viability and function in transit is critically important. Gas-permeable silicone rubber membrane (SRM) vessels reduce the risk of hypoxia-induced death or dysfunction during high-density islet culture or shipment. SRM vessels may offer additional advantages: they are cost-effective (fewer flasks, less labor needed), safer (lower contamination risk), and simpler (culture vessel can also be used for shipment). Human islets(IE) were isolated from two manufacturing centers and shipped in 10cm(2) surface area SRM vessels in temperature and pressure controlled containers to a distant center following at least two days of culture (n = 6). Three conditions were examined: low density (LD), high density (HD), and a micro centrifuge tube negative control (NC). LD was designed to mimic the standard culture density for human islet preparations (200 IE/cm(2)), while HD was designed to have a 20-fold higher tissue density, which would enable the culture of an entire human isolation in 1–3 vessels. Upon receipt, islets were assessed for viability, measured by oxygen consumption rate normalized to DNA content (OCR/DNA), and quantity, measured by DNA, and, when possible, potency and function with dynamic glucose-stimulated insulin secretion (GSIS) measurements and transplants in immunodeficient B6 rag mice. Post-shipment OCR/DNA was not reduced in HD versus LD, and was substantially reduced in the NC condition. HD islets exhibited normal function post-shipment. Based on the data we conclude that entire islet isolations (up to 400,000 IE) may be shipped using a single, larger SRM vessel with no negative effect on viability and ex vivo and in vivo function