Modeling oxygen transport in a cylindrical bioartificial pancreas

Encapsulated pancreatic islets in a cylindrical hollow fiber have been reported to reverse diabetes in test animals; however, for many of these animals, the effects have only been temporary. Oxygen deficiency within the fiber has been proposed as a cause of the observed loss of islet viability. A mathematical model of transport and reaction kinetics in a bioartificial pancreas (BAP) has been developed to calculate the oxygen concentration profiles in a cylindrical BAP. Simulation results indicate that hypoxic conditions will exist in large diameter fibers or fibers with islet concentrations >20,000 islets/ml. Moreover, our results show that a significant amount of oxygen is consumed in the tissue region surrounding the cylindrical BAP. Even if the islet survives in a low-oxygen environment, the insulin productivity will likely be reduced.