Imaging of glutamate neurotransmitter alterations in Alzheimer's disease

Glutamate (Glu) is a major excitatory neurotransmitter in the brain and has been shown to decrease in the early stages of Alzheimer's disease (AD). Using a glutamate chemical (amine) exchange saturation transfer (GluCEST) method, we imaged the change in [Glu] in the APP-PS1 transgenic mouse model of AD at high spatial resolution. Compared with wild-type controls, AD mice exhibited a notable reduction in GluCEST contrast (similar to 30%) in all areas of the brain. The change in [Glu] was further validated through 1H MRS. A positive correlation was observed between GluCEST contrast and 1H MRS-measured Glu/total creatine ratio. This method potentially provides a novel noninvasive biomarker for the diagnosis of the disease in preclinical stages and enables the development of disease-modifying therapies for AD. Copyright (c) 2012 John Wiley & Sons, Ltd.