Insulin-like growth factor-1 in CNS and cerebrovascular aging

Insulin-like growth facto-1 (IGF-1) is an imprtant anabolic hormone that decreases with age. In the past two decades, extensive research has determined that the reduction in IGF-1 is an important component of the age-related decline in cognitive function in multiple species including humans. Deficiency in circulating IGF-1 results in impairment in processing speed and deficiencies in both spatial and working memory. Replacement of IGF-1 or factors that increase IGF-1 to told animals and humans reverses many of these cognitive deficits. Despite the overwhelming evidence of IGF-1 as an important neurotrophic agent, the specific mechanism through which IGF-1 as an important neurotrophic agent, the specific mechanisms through which IGF-1 acts have remained elusive. Recent evidence indicates that IGF-1 is both produced by and has important actions on the cerebrovasculature as well as neurons and glia. Nevertheless, the specific regulation and actions of brain- and vascular-derived IGF-1 is poorly understood. The diverse effects of IGF-1 discoverd thus far reveal a complex endocrine and paracrine system essential for integrating many of the functions necessary for brain health. Identification of the mechanism of IGF-1 actions will undoubtly provide critical insight into regulation of brain function in general and the causes of cognitive decline with age.