Combined effects of temperature and diet on the performance of larvae produced by young and old Palaemon serratus females.

Seasonal variations in environmental conditions determine the success of decapod larval development, and females transmit more energy in sub-optimal conditions to maximise the fitness of their offspring. The objective of this study was to focus on the combined effects of temperature (14, 18 and 22 °C) and food quality on the performance of larvae produced by 5 young (0+) and 5 old (I+) Palaemon serratus females. We prepared 3 diets based on Artemia, in decreasing order of total fatty acid content: freshly hatched nauplii (N), unenriched metanauplii (M) and metanauplii enriched with a mixture of microalgae (ME). At hatching, the larvae produced by I+ females had a higher biomass but a similar fatty acid concentration to those produced by 0+ females. Larvae survived better and developed relatively faster as temperature increased, and the longer they waited to metamorphose, the greater their weight at metamorphosis. These performances were diet-dependent, with more survival and more growth in less time with diet N than with the other two. Larvae from I+ females performed better than those from 0+ females, especially under the most stressful conditions. The greater biomass of the larvae of I+ females seems to have enabled them to follow a shorter, and therefore faster, development path than those of 0+ females. The larvae's diet also had an impact on post-metamorphic composition: larvae eating a diet richer in fatty acids produced richer juveniles and those eating a poorer diet produced juveniles with slightly more essential fatty acids. This study supports the high plasticity of caridean shrimp larval development and the importance of maternal effects on the fitness of offspring.

Safety and function of a new pre-vascularized bioartificial pancreas in an allogeneic rat model.

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.

Integration of nano- and biotechnology for beta-cell and islet transplantation in type-1 diabetes treatment.

Regenerative medicine using human or porcine ß-cells or islets has an excellent potential to become a clinically relevant method for the treatment of type-1 diabetes. High-resolution imaging of the function and faith of transplanted porcine pancreatic islets and human stem cell-derived beta cells in large animals and patients for testing advanced therapy medicinal products (ATMPs) is a currently unmet need for pre-clinical/clinical trials. The iNanoBIT EU H2020 project is developing novel highly sensitive nanotechnology-based imaging approaches allowing for monitoring of survival, engraftment, proliferation, function and whole-body distribution of the cellular transplants in a porcine diabetes model with excellent translational potential to humans. We develop and validate the application of single-photon emission computed tomography (SPECT) and optoacoustic imaging technologies in a transgenic insulin-deficient pig model to observe transplanted porcine xeno-islets and in vitro differentiated human beta cells. We are progressing in generating new transgenic reporter pigs and human-induced pluripotent cell (iPSC) lines for optoacoustic imaging and testing them in transplantable bioartificial islet devices. Novel multifunctional nanoparticles have been generated and are being tested for nuclear imaging of islets and beta cells using a new, high-resolution SPECT imaging device. Overall, the combined multidisciplinary expertise of the project partners allows progress towards creating much needed technological toolboxes for the xenotransplantation and ATMP field, and thus reinforces the European healthcare supply chain for regenerative medicinal products.

A fully implantable device for diffuse insulin delivery at extraperitoneal site for physiological treatment of type 1 diabetes.

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.