PMID- 36072843
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20220910
IS  - 1664-042X (Print)
IS  - 1664-042X (Electronic)
IS  - 1664-042X (Linking)
VI  - 13
DP  - 2022
TI  - Application of a multicomponent model of convectional reaction-diffusion to 
      description of glucose gradients in a neurovascular unit.
PG  - 843473
LID - 10.3389/fphys.2022.843473 [doi]
LID - 843473
AB  - A supply of glucose to a nervous tissue is fulfilled by a cerebrovascular 
      network, and further diffusion is known to occur at both an arteriolar and a 
      microvascular level. Despite a direct relation, a blood flow dynamic and 
      reaction-diffusion of metabolites are usually considered separately in the 
      mathematical models. In the present study they are coupled in a multiphysical 
      approach which allows to evaluate the effects of capillary blood flow changes on 
      near-vessels nutrient concentration gradients evidently. Cerebral blood flow 
      (CBF) was described by the non-steady-state Navier-Stokes equations for a 
      non-Newtonian fluid whose constitutive law is given by the Carreau model. A 
      three-level organization of blood-brain barrier (BBB) is modelled by the flux 
      dysconnectivity functions including densities and kinetic properties of glucose 
      transporters. The velocity of a fluid flow in brain extracellular space (ECS) was 
      estimated using Darcy's law. The equations of reaction-diffusion with convection 
      based on a generated flow field for continues and porous media were used to 
      describe spatial-time gradients of glucose in the capillary lumen and brain 
      parenchyma of a neurovascular unit (NVU), respectively. Changes in CBF were 
      directly simulated using smoothing step-like functions altering the difference of 
      intracapillary pressure in time. The changes of CBF cover both the decrease (on 
      70%) and the increase (on 50%) in a capillary flow velocity. Analyzing the 
      dynamics of glucose gradients, it was shown that a rapid decrease of a capillary 
      blood flow yields an enhanced level of glucose in a near-capillary nervous tissue 
      if the contacts between astrocytes end-feet are not tight. Under the increased 
      CBF velocities the amplitude of glucose concentration gradients is always 
      enhanced. The introduced approach can be used for estimation of blood flow 
      changes influence not only on glucose but also on other nutrients concentration 
      gradients and for the modelling of distributions of their concentrations near 
      blood vessels in other tissues as well.
CI  - Copyright (c) 2022 Nartsissov.
FAU - Nartsissov, Yaroslav R
AU  - Nartsissov YR
AD  - Department of Mathematical Modeling and Statistical Analysis, Institute of 
      Cytochemistry and Molecular Pharmacology, Moscow, Russia.
LA  - eng
PT  - Journal Article
DEP - 20220822
PL  - Switzerland
TA  - Front Physiol
JT  - Frontiers in physiology
JID - 101549006
PMC - PMC9444140
OTO - NOTNLM
OT  - blood flow
OT  - blood-brain barrier
OT  - neurovascular unit
OT  - nutrients
OT  - reaction-diffusion
COIS- The authors declare that the research was conducted in the absence of any 
      commercial or financial relationships that could be construed as a potential 
      conflict of interest.
EDAT- 2022/09/09 06:00
MHDA- 2022/09/09 06:01
PMCR- 2022/08/22
CRDT- 2022/09/08 02:33
PHST- 2021/12/26 00:00 [received]
PHST- 2022/07/18 00:00 [accepted]
PHST- 2022/09/08 02:33 [entrez]
PHST- 2022/09/09 06:00 [pubmed]
PHST- 2022/09/09 06:01 [medline]
PHST- 2022/08/22 00:00 [pmc-release]
AID - 843473 [pii]
AID - 10.3389/fphys.2022.843473 [doi]
PST - epublish
SO  - Front Physiol. 2022 Aug 22;13:843473. doi: 10.3389/fphys.2022.843473. eCollection 
      2022.