How abundant are superoxide and hydrogen peroxide in the vasculature lumen, how far can they reach?

Paracrine superoxide (O2•−) and hydrogen peroxide (H2O2) signaling critically depends on these substances' concentrations, half-lives and transport ranges in extracellular media. Here we estimated these parameters for the lumen of human capillaries, arterioles and arteries using reaction-diffusion-advection models. These models considered O2•− and H2O2 production by endothelial cells and uptake by erythrocytes and endothelial cells, O2•− dismutation, O2•− and H2O2 diffusion and advection by the blood flow. Results show that in this environment O2•− and H2O2 have half-lives <60. ms and