Biotechnologie et biomatériaux

Abstrait

A nanofluidic paradigm and approach to brain water metabolism

Ernst Titovets

The brain interstitial fluid, presenting an external medium for the neural cells, is involved in the nutrient and gas transport, non-synaptic intercellular communication (volume transmission), signal transduction, transport and targeted delivery of drugs and metabolites, ionic homeostasis, removal of pathogenic metabolites, the migration of cells (malignant cells, stem cells), transfer of heat generated by neuractivity
The nanodimentionality of the brain interstitial space has born a dominating opinion within the medico-biological community of a diffusion barrier to water movement and mass transfer events there. On the other hand, the very nanodimentionality of the brain interstitial space dictates the
use of the slip-flow principles of nanofluidics to describe water movement there. The fluid flow in the nanodimentional spaces is usually many orders of magnitude higher than predicted from the conventional no-slip approach. The nanofluidic paradigm to the water movement in the
brain interstitial space has been used by us to describe a nanofluidic mechanism of brain water metabolism. There has been carried out computer simulations, based on the new principle, of the mass transfer of glucose, oxygen and carbon dioxide within the neurovascular unite. We simulated the effects on the brain water metabolism of AQP4 polarization in the astrocyte endfeet membrane enveloping capillaries. Possible clinical implications of the simulation results are discussed. In particular, the nanofluidic mechanism might be used to develop the AQP4-targeted drug therapy of brain edema, drug delivery to brain tumors, removal of pathogenic metabolites and other.