Chapter 7 Monitoring Oxidative Stress in Vascular Endothelial Cells in Response to Fluid Shear Stress: From Biochemical Analyses to Micro- and Nanotechnologies

Hemodynamics, specifically, fluid shear stress, modulates the focal nature of atherosclerosis. Shear stress induces vascular oxidative stress via the activation of membrane-bound NADPH oxidases present in vascular smooth muscle cells, fibroblasts, and phagocytic mononuclear cells. Shear stress acting on the endothelial cells at arterial bifurcations or branching points regulates both NADPH oxidase and nitric oxide (NO) synthase activities. The former is considered a major source of oxygen-centered radicals (i.e., superoxide anion [O₂^{· -}]) that give rise to oxidative stress; the latter is a source of nitrogen-centered radicals (i.e., nitric oxide [NO]) that give rise to nitrative/nitrosative stress. In addition to conventional biochemical analyses, the emerging microelectromechanical systems (MEMS) provide spatial and temporal resolutions to investigate the mechanisms whereby the characteristics of shear stress regulate the biological activities of endothelial cells at the complicated arterial geometry. In parallel, the development of MEMS liquid chromatography (LC) provides a new venue to measure circulating oxidized low-density lipoprotein (ox-LDL) particles as a lab-on-a chip platform. Nanowire-based field effect transistors further pave the way for a high throughput approach to analyze the LDL redox state. Integration of MEMS with oxidative biology is synergistic in assessing vascular oxidative stress. The MEMS LC provides an emerging lab-on-a-chip platform for ox-LDL analysis. In this context, this chapter has integrated expertise from the fields of vascular biology and oxidative biology to address the dynamics of inflammatory responses.