1- Independent researcher 2- , Department of Biochemistry and Biophysics, TeMS.C., Islamic Azad University, Tehran, Iran , drissalayali@gmail.com 3- Master's Student in Biochemistry, TeMS.C., Islamic Azad University, Tehran, Iran
Abstract: (3 Views)
Background: The association between insulin resistance and Alzheimer's disease (AD) has been proposed as the "type 3 diabetes" hypothesis. This systematic review investigates the role of impaired cerebral insulin signaling in the pathogenesis of AD and its therapeutic prospects. Materials and methods: Following the PRISMA guidelines, a comprehensive search was conducted in PubMed/MEDLINE, Scopus, and Web of Science databases up to 2025. After screening, 32 studies were included in the review. Results: Cerebral insulin resistance is a key pathological factor in AD that acts through independent mechanisms. It impairs amyloid-beta (Aβ) clearance by reducing the activity of insulin-degrading enzyme (IDE) and by disrupting the PI3K/Akt pathway, leads to GSK-3β activation and tau hyperphosphorylation. These processes, together with impaired neurotransmission and inflammation, form a vicious cycle of neurodegeneration and support the concept of type 3 diabetes. In contrast, emerging therapies such as intranasal insulin and GLP-1 agonists have shown potential to improve molecular markers and cognition in early studies. Conclusion: Cerebral insulin resistance is an important and targetable causal component in the pathogenesis of AD. Targeting this pathway is a promising therapeutic strategy. However, challenges such as standardization of measurement, rigorous trial design, and crossing the blood-brain barrier require attention before widespread clinical application. Future research should focus on identifying biomarkers and developing combination therapies.
Torabi Goodarzi S, Layali I, Nematollah Z. Interaction of insulin hormone with neurotransmitters in the pathogenesis of Alzheimer's disease. MEDICAL SCIENCES 2026; 36 (3) :281-288 URL: http://tmuj.iautmu.ac.ir/article-1-2492-en.html