Alterations in Glucose Metabolism in Alzheimer's Disease

Background: Alzheimer's disease (AD) is the most frequent type of dementia in people over 65 years of age; type 2 diabetes mellitus is a metabolic condition affecting 382 million of adults worldwide. Glucose is the main substrate for energy for the brain, which consumes 25% of the body's glucose. Glucose metabolism, evaluated using Positron Emission Tomography (PET) scanning using 18F-fluorodeoxyglucose ([18F]-FDG) is commonly used for diagnosis and follow up in AD. Epidemiological and pathophysiological studies showed a link between AD and diabetes, particularly in relation to insulin resistance. Objective: In this paper, we discuss how [18F] FDG is a marker of glucose metabolism, how insulin resistance is related to diabetes, the link between diabetes and AD, and how novel treatments for diabetes could be beneficial in the treatment of Alzheimer's disease. We also review few recent patents in the field, suggesting both diagnostic and therapeutic potential approaches. Methods: The electronic searches were performed in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases. We also manually searched abstract books and reviewed available recent patents on specific websites. Results: The impaired glucose metabolism in the brain of subject with AD is a widely recognised early feature of the disease; in vivo evaluation with PET is a useful diagnostic tool. The link between diabetes and neurodegeneration is widely recognized and offer a target for novel therapeutic strategies. Conclusions: Early diagnosis and early therapeutic intervention are needed to approach this devastating disease. Important studies targeting different aspect of the disease are currently ongoing.