Review
Copyright ©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. Jul 15, 2024; 15(7): 1430-1447
Published online Jul 15, 2024. doi: 10.4239/wjd.v15.i7.1430
Insulin resistance as the molecular link between diabetes and Alzheimer's disease
Mona Mohamed Ibrahim Abdalla
Mona Mohamed Ibrahim Abdalla, Department of Human Biology, School of Medicine, International Medical University, Bukit Jalil 57000, Kuala Lumpur, Malaysia
Author contributions: Abdalla MMI designed the research, searched the databases, and wrote the paper.
Conflict-of-interest statement: The author has nothing to disclose.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Mona Mohamed Ibrahim Abdalla, MSc, PhD, Senior Lecturer, Department of Human Biology, School of Medicine, International Medical University, No. 126 Jln Jalil Perkasa 19, Bukit Jalil 57000, Kuala Lumpur, Malaysia. monamohamed@imu.edu.my
Received: February 14, 2024
Revised: April 8, 2024
Accepted: May 6, 2024
Published online: July 15, 2024
Processing time: 144 Days and 18.7 Hours
Abstract

Diabetes mellitus (DM) and Alzheimer's disease (AD) are two major health concerns that have seen a rising prevalence worldwide. Recent studies have indicated a possible link between DM and an increased risk of developing AD. Insulin, while primarily known for its role in regulating blood sugar, also plays a vital role in protecting brain functions. Insulin resistance (IR), especially prevalent in type 2 diabetes, is believed to play a significant role in AD's development. When insulin signalling becomes dysfunctional, it can negatively affect various brain functions, making individuals more susceptible to AD's defining features, such as the buildup of beta-amyloid plaques and tau protein tangles. Emerging research suggests that addressing insulin-related issues might help reduce or even reverse the brain changes linked to AD. This review aims to explore the rela-tionship between DM and AD, with a focus on the role of IR. It also explores the molecular mechanisms by which IR might lead to brain changes and assesses current treatments that target IR. Understanding IR's role in the connection between DM and AD offers new possibilities for treatments and highlights the importance of continued research in this interdisciplinary field.

Keywords: Alzheimer's disease; Insulin resistance; Obesity; Dementia; Diabetes; Metabolic syndrome

Core Tip: Insulin resistance (IR), commonly associated with type 2 diabetes, is a crucial factor linking diabetes mellitus to Alzheimer's disease (AD). While insulin is primarily known for regulating blood sugar, it also plays a significant role in brain health. Dysfunctional insulin signaling, characteristic of IR, adversely impacts brain functions and is implicated in the development of AD's defining features, such as beta-amyloid plaques and tau protein tangles. Understanding and addressing IR early could offer new treatment strategies for AD, highlighting the importance of continued research in this interdisciplinary field.