Two‐dimensional model for prediction of arteriolar NO/O2 modulation by spatiotemporal variations in cell‐free layer (678.13)

Abstract

The role of cell‐free layer (CFL) in modulating nitric oxide (NO) and oxygen (O2) transport has been of particular interest in many microcirculatory studies. Despite the significant roles of CFL in balancing NO/O2 bioavailability in arteriolar tissue, many of previous numerical approaches have relied on a one‐dimensional steady‐state model for simplicity. However, these models are incapable of providing information on the influence of spatiotemporal variations in CFL on the NO/O2 transport under dynamic flow conditions. Therefore, the present study proposes a new two‐dimensional transient model capable of predicting NO/O2 transport modulated by dynamic changes in the CFL width. The CFL width data were obtained from an in vivo experiment performed in the rat cremaster muscle. Our new model revealed that the NO bioavailability could be inversely related to the CFL width. The enhancement of NO production by greater wall shear stress with a thinner CFL could dominate the diffusion barrier role of the CFL preventing NO scavenging by RBCs. In addition, the NO/O2 availability along the vascular wall was not homogeneous and highly regulated by dynamic changes of the local CFL width variation. The time‐averaged spatial variations of the CFL widths on opposite sides of the arteriole exhibited a significant inverse relation. This asymmetric formation of CFL resulted in signifcantly imbalanced NO/O2 bioavailability in the tissues on opposite sides of the arteriole. This work was supported by NMRC/CBRG/0019/2012.Grant Funding Source: Supported by NMRC/CBRG/0019/2012.