Modeling O2-dependent effects of nitrite reductase activity in blood and tissue on coupled NO and O2 transport around arterioles

Abstract

Recent evidence in the literature suggests that tissues play a greater role than blood in reducing nitrite to NO under ischemic or hypoxic conditions. Our previous mathematical model for coupled NO and O2 transport around an arteriole, modified to include superoxide generation from dysfunctional endothelium, was developed further to include nitrite reductase activity in blood and tissue. Steady-state radial and axial NO and pO2 profiles in the arteriole and surrounding tissue were simulated for different blood flow rates and arterial blood pO2 values. The resulting computer simulations demonstrate that nitrite reductase activity in blood is not a very effective mechanism for conserving NO due to the strong scavenging of NO by hemoglobin. In contrast, nitrite reductase activity in tissue is much more effective in increasing NO bioavailability in the vascular wall and contributes progressively more NO as tissue hypoxia becomes more severe. © 2011 Springer Science+Business Media, LLC.