Oxygen and inulin transport measurements in a planar tissue-engineered bioartificial organ

In vivo oxygen and inulin transport rates were measured in a planar tissue-engineered bioartificial organ implanted in a rat. A compartmental model was used to describe the transport of oxygen and inulin between the cell chamber, across the immunoisolation membrane, and within the neovascularized region adjacent to the immunoisolation membrane. A nonlinear regression analysis of the plasma inulin levels and the oxygen transport rate into the device provided information on the degree of vascularization in the region adjacent to the bioartificial organ. Key parameters that were obtained from the analysis of the in vivo transport data included the average capillary blood oxygen partial pressure, the Krogh tissue cylinder radius, the extracellular volume fraction, and the capillary blood residence time. These four parameters are important indicators for assessing the degree of vascularization in the tissue adjacent to the immunoisolation membrane in the bioartificial organ. The oxygen and inulin transport technique reported here is a useful tool for describing the in vivo transport characteristics of a bioartificial organ and for assessment of the vascularization within tissue engineered structures.