Is Alzheimerʹs disease, type 3 diabetes?

Abstract

Alzheimer's Disease (AD) is the most common cause of dementia. The term of 'type 3 diabetes' is constituted to point out the insulin deficiency and resistant in brain of people with AD. In postmortem studies about AD, it has ben detected that insulin receptors, insulin-like growth factor 1 and 2, insulin messenger ribonucleic acid are decreased in brain. Insulin can pass through brain-blood-barrier, besides it can be synthesized by a group of neuron internally. Gene expression of insulin is present in mature and immature neurons of mammals. Insulin has important effects on regulation of energy metabolism of neurons and neuronal recovery. Decreased glucose uptake and adenosine triphosphate production in the case of insulin deficiency, leads an impairment in neuronal homeostasis. Insulin can increase cognitive functions without changing plasma glucose and insulin levels when it applied intranasally. Insulin and its sub-pathways will maintain its current importance about improvement and protection of cognitive functions.