Influence of oxygen uptake through the liver surface on the metabolism of ex vivo perfused liver during hypoxia.

The low quality of transplants having undergone hypoxic injury can lead to postoperative complications. The aim of the present research is to estimate, by means of mathematical modeling, how the process of oxygen uptake through the liver surface influences the metabolism of ex vivo perfused liver under hypoxia. The value of oxygen uptake through the surface was established to depend on the degree of oxygenation of the perfusion medium. A decrease in the oxygenation of the perfusion medium resulted in a decreased oxygen uptake through the liver surface. Stoichiometric modeling of the liver metabolism shows that upon the decreased oxygenation of the perfusion medium more energy is required for the process of oxygen uptake through the surface even at a lower level as compared to the normal oxygen supply. The application of the Pareto optimality allows estimating the optimum distribution of the energy resources in liver under ex vivo conditions. Both upon the normal and decreased oxygenation of the perfusion medium, the phenomenon of "free competition" for the resource was observed, with the energy being optimally distributed among all the metabolic fluxes. Moreover, this energy is also spent on the accompanying processes, e.g. for the transport of interstitial fluid.