Type 3 Diabetes Mellitus: A Novel Implication of Alzheimers Disease

The brain of patients with Alzheimer disease (AD) showed the evidence of reduced expression of insulin and neuronal insulin receptors, as compared with those of age-matched controls. This event gradually and certainly leads to a breakdown of the entire insulin-signaling pathway, which manifests insulin resistance. This in turn affects brain metabolism and cognitive functions, which are the bestdocumented abnormalities in AD. These observations led Dr. de la Monte and her colleagues to suggest that AD is actually a neuroendocrine disorder that resembles type 2 diabetes mellitus. The truth would be more complex with understanding the role of low-density lipoprotein receptor-related protein 1, Aβ derived diffusible ligands, and advanced glycation end products. However, now it known as “brain diabetes” and is called type 3 diabetes mellitus (T3DM). This review provides an overview of “brain diabetes” focusing on the reason why the phenomenon is called T3DM.