Xiao-Hong Zhu1, Ming Lu1, Yi Zhang1, Wei Chen2
1Center of Magnetic Resonance Research, Department of Radiology, University of Minnesota Medical School, Minneapolis, MN, United States; 2Center of Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, United States
Nicotinamide adenine dinucleotide (NAD), as an important coenzyme and/or co-substrate in all living cells, plays vital roles in cellular metabolism and regulation. However, due to the technique limitation, it is very difficult to directly measure the NAD and its redox state (define as the ratio of oxidized and reduced forms: NAD+/NADH) in a live brain. We have developed an in vivo 31P MRS approach that is capable of quantitative and non-invasive imaging of the intracellular NAD levels and the NAD+/NADH ratio in intact organs, such as brain. In the present study, we applied this novel MRS approach to image the intracellular NAD contents, including the NAD+, NADH and total NAD concentrations, and the NAD+/NADH redox ratio in anesthetized cat brain under normal physiological condition, and in the rat brains under acute ischemia-recovery conditions. The results indicate that the NAD imaging approach can provide reliable measure of the cerebral NAD contents and redox state and is sensitive to detect their changes in response to physiopathological alteration in brain energy and metabolism; thus, has great values for basic biomedical research and potential for clinical translation.