THE beta AIR registered : IMPLANTABLE BIO-ARTIFICIAL PANCREAS (BAP)

Objectives: Current therapy for insulin-dependent patients requires frequent blood glucose testing and insulin injections. Quite often, this treatment does not result in optimized control over blood glucose. Islet transplantation could form the optimal solution for these patients once two key targets are met: adequate oxygenation and efficient immune protection of the donor tissue. The sub-dermal implanted beta Air registered is designed to overcome both hurdles. Methods: The beta Air registered is a two compartment device. Donor islets of Langerhans immobilized in a flat sheet hydrogel and an oxygen chamber separated from the islet module by a gas permeable membrane. The immune barrier is a three-layer system: a 0.4 mu m hydrophilyzed Teflon membrane, that prevents cell-cell contact, thus preventing cellular immunity; a small pore size alginate hydrogel Impregnated into the Teflon membrane, significantly inhibiting inward diffusion of immune macromolecules and a large flat alginate hydrogel inflicting with the capacity of cytokines and NO to affect the islets. Results: The beta Air registered was implanted in small and large animals. Average blood glucose levels were adjusted to near normal for up to 6 months in iso and allogenic diabetic rats and for one month in large xenogenic pig. Upon retrieval, blood glucose levels returned to the disease state. No pig's DNA was found within the device. Migration of IgG across the impregnated membrane was reduced by 20 fold, suggesting a strict delay in penetration of antibodies and other components of the immune system. More than 90% of the alginate was maintained with minor toss of the cross linking ion, suggesting a stable alginate gel. Conclusions: Results demonstrate the ability of the beta Air registered to treat diabetes in rats and pigs with long-term immuno protection.