We published a brain MRS study showing for the first time that patients with AD have higher glucose and lactate concentrations and lower glutamate and GABA concentrations in the precuneus, a critical area for Alzheimer's disease. In particular, the finding of higher glucose concentration in Alzheimer's is the mirror image of decreased glucose utilization seen in FDG PET studies in the disease. MRS Glucose levels helped discriminate patients with Alzheimer's from controls and they may be a promising novel biomarker for the disease. Interestingly MRS glucose was also increased in a study of patients with Schizophrenia conducted by an extramural collaborator. In collaboration with Drs. Chia and Egan, we are analyzing MRI scans from the RISE study, a multi-faceted randomized placebo-controlled cross-over clinical study on the effects of a CB1 receptor agonist and antagonist on peripheral metabolism, brain function and brain metabolic control. The study included a robust neuroimaging component including fMRI and MRS. We performed two activation-paradigm fMRI studies, one to discover brain correlates of cephalic insulin secretion and the effects of CB1 receptors, the second to assess the effects of CB1 receptors on food appetitiveness. The goal of the first study was to demonstrate a rise in insulin levels in response to food visual stimuli (cephalic insulin response) as a result of activation of certain brain areas (insula, anterior cingulate, hypothalamus, ventral tegmental area, etc). Moreover, given the presence of CB1 receptors in the candidate areas, we aimed to demonstrate a difference in their level of activation with CB1 agonists and antagonists. The goal of the second study was to demonstrate dissociable effects of CB1 receptor stimulation on food value (food choices) and salience (intensity of such choices). In addition, we performed a resting fMRI study to assess CB1 modulation of functional connectivity of the various brain networks. Finally, we performed MRS to assess CB1 modulation of brain metabolism (glucose, lactate) and neurotransmission (glutamate, GABA, glycine). We are currently in the process of analyzing and interpreting the data from these studies.
| Mullins, Roger; Reiter, David; Kapogiannis, Dimitrios (2018) Magnetic resonance spectroscopy reveals abnormalities of glucose metabolism in the Alzheimer's brain. Ann Clin Transl Neurol 5:262-272 |
| Mullins, Roger J; Diehl, Thomas C; Chia, Chee W et al. (2017) Insulin Resistance as a Link between Amyloid-Beta and Tau Pathologies in Alzheimer's Disease. Front Aging Neurosci 9:118 |
| Willette, Auriel A; Modanlo, Nina; Kapogiannis, Dimitrios et al. (2015) Insulin resistance predicts medial temporal hypermetabolism in mild cognitive impairment conversion to Alzheimer disease. Diabetes 64:1933-40 |
| Willette, Auriel A; Kapogiannis, Dimitrios (2015) Does the brain shrink as the waist expands? Ageing Res Rev 20:86-97 |
| Kapogiannis, Dimitrios; Deshpande, Gopikrishna; Krueger, Frank et al. (2014) Brain networks shaping religious belief. Brain Connect 4:70-9 |
| Willette, Auriel A; Calhoun, Vince D; Egan, Josephine M et al. (2014) Prognostic classification of mild cognitive impairment and Alzheimer's disease: MRI independent component analysis. Psychiatry Res 224:81-8 |
| Kapogiannis, Dimitrios; Reiter, David A; Willette, Auriel A et al. (2013) Posteromedial cortex glutamate and GABA predict intrinsic functional connectivity of the default mode network. Neuroimage 64:112-9 |
| Kapogiannis, Dimitrios; Sutin, Angelina; Davatzikos, Christos et al. (2013) The five factors of personality and regional cortical variability in the Baltimore longitudinal study of aging. Hum Brain Mapp 34:2829-40 |
| Kapogiannis, Dimitrios; Kisser, Jason; Davatzikos, Christos et al. (2012) Alcohol consumption and premotor corpus callosum in older adults. Eur Neuropsychopharmacol 22:704-10 |
| Makrogiannis, Sokratis; Ramachandran, Ramona; Fishbein, Kenneth W et al. (2011) Towards segmentation of the thymus in fat and water parametric MR images. Conf Proc IEEE Eng Med Biol Soc 2011:8078-81 |
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