In Vivo Detection of Transition Metals and Nitrosyl-Heme Complexes Using Ex Vivo Electron Paramagnetic Resonance Spectroscopy

Cellular redox environment is a critical determinant of stress-induced cellular responses and the progression of disease (1 ). Under normal (nonstress) conditions, the cell maintains a strong reducing environment that favors reductive over highly compartmentalized oxidative biochemistry. Exposure of cellular macromolecules to reactive oxygen (ROS) and reactive nitrogen species (RNS) is tightly controlled. Environmental stress can shift the redox balance away from reductive biochemistry however, promoting transition metal activation, and nonprogrammed oxidative and/or nitrosative reactions. Metalcatalyzed oxidative and nitrosative stress have been implicated in the etiology of numerous clinical disorders including inflammation, ischemia-reperfusion injury, rheumatoid arthritis, and aging (1 ).