RESUMO
Cell encapsulation could overcome limitations of free islets transplantation but is currently limited by inefficient cells immune protection and hypoxia. As a response to these challenges, we tested in vitro and in vivo the safety and efficacy of a new macroencapsulation device named MailPan®. Membranes of MailPan® device were tested in vitro in static conditions. Its bio-integration and level of oxygenation was assessed after implantation in non-diabetic rats. Immune protection properties were also assessed in rat with injection in the device of allogeneic islets with incompatible Major Histocompatibility Complex. Finally, function was assessed in diabetic rats with a Beta cell line injected in MailPan®. In vitro, membranes of the device showed high permeability to glucose, insulin, and rejected IgG. In rat, the device displayed good bio-integration, efficient vascularization, and satisfactory oxygenation (>5%), while positron emission tomography (PET)-scan and angiography also highlighted rapid exchanges between blood circulation and the MailPan®. The device showed its immune protection properties by preventing formation, by the rat recipient, of antibodies against encapsulated allogenic islets. Injection of a rat beta cell line into the device normalized fasting glycemia of diabetic rat with retrieval of viable cell clusters after 2 months. These data suggest that MailPan® constitutes a promising encapsulation device for widespread use of cell therapy for type 1 diabetes.
RESUMO
Intraperitoneal insulin delivery has higher benefits than subcutaneous insulin administration but has limitations, including obstruction of the catheter used in delivery devices. To overcome these limitations this study assessed safety and efficacy of an alternative approach involving a new delivery device, named ExOlin®, allowing diffuse release of insulin in the extraperitoneal site. The aim of this study is to validate both safety and efficacy of insulin delivery in extraperitoneal using ExOlin® device. Safety of the ExOlin® device implantation in the extraperitoneal site was investigated over a 3-month period in Wistar rat and landrace swine models before comparing efficacy pharmacokinetics and hepatic first-pass metabolism of insulin after focal delivery using a catheter or diffuse release via ExOlin® device in extraperitoneal. Implantation in rat and swine models demonstrated good integration of the device, validating the safety of the extraperitoneal site. In diabetic rats, direct insulin administration at the extraperitoneal showed an efficacy comparable to intraperitoneal and statistically significantly higher than subcutaneous route as shown by 23% lower AUC calculated from glycaemia profile. Diffuse extraperitoneal delivery of insulin via ExOlin® device in diabetic rats exhibited better efficacy than the subcutaneous route with up to six-fold lower peripheral insulin and higher hepatic first-pass than with intraperitoneal injection. Similar results were confirmed in the swine model after injecting insulin lispro via the device at the extraperitoneal site. In conclusion, diffuse administration of insulin at the extraperitoneal site via ExOlin® device is a new promising approach to physiologically treating type 1 diabetes. It can therefore be considered as a promising alternative to intraperitoneal route.