THEORETICAL AND EXPERIMENTAL-ANALYSIS OF A HYBRID BIOARTIFICIAL MEMBRANE PANCREAS - A DISTRIBUTED PARAMETER MODEL TAKING INTO ACCOUNT STARLING FLUXES

Membrane bioreactors have been extensively used both in the medical and the industrial field. When cells are entrapped in the reactor shell, experimental evidence shows the existence of convective fluxes through the reactor shell side. Nevertheless, solute transport to and from the iramobilized cells has been mostly assumed to occur by diffusion only. This paper reports on the authors'ex vivo and in vitro experimental work with a hybrid bioartificial membrane pancreas (HBMP), in which porcine islets of Langerhans were segregated in the shell side of a hollow fibre module. The purpose of the paper is to outline the important role played by convective fluxes in determining reactor performance, in particular when the HBMP is usedin vivo. Hydraulic parameters estimated fromex vivo experiments, where the HBMP was implanted as an arterio-venous shunt between the aorta and vena cava in Landrace pigs, show that convection contributes to solute transport to and from the shell as much as diffusion. Kinetic parameters for insulin delivery by the islets were estimated fromin vitro experiments at various feed flow rates. A distributed parameter model, taking into account radial convective fluxes in the reactor shell side, is also proposed for a better description of mass transfer and kinetic phenomena occurring in this kind of bioreactor. © 1990.