During the last decade, a significant body of evidence has accumulated, indicating that
IGF-I might play a role in several pathological conditions commonly seen during aging, such as
atherosclerosis and
cardiovascular disease (CVD),
cognitive decline,
dementia,
sarcopenia and
frailty. A vascular protective role for
IGF-I has been suggested because of its ability to stimulate
nitric oxide production from endothelial and vascular smooth muscle cells. In cross sectional studies, low
IGF-I levels have been associated with unfavorable CVD risk factors profile, such as
atherosclerosis, abnormal
lipoprotein levels and
hypertension, while in prospective studies, lower
IGF-I levels predict future development of
ischemic heart disease. The fall in
IGF-I levels with aging correlates with
cognitive decline and it has been suggested that
IGF-I plays a role in the development of
dementia.
IGF-I is highly expressed within the brain and is essential for normal brain development.
IGF-I has anti-apoptotic and
neuroprotective effects and promotes projection neuron growth, dendritic arborization and synaptogenesis. Collectively, these data are consistent with a causal link between the age-related decline in GH and
IGF-I levels and cognitive deficits in older persons. Finally, there is evidence of a relationship between declining GH and
IGF-I levels and age-related changes in body composition and physical function. However, few studies have documented a precise role of
IGF-I in the development of
sarcopenia,
frailty and poor mobility. We have recently documented that serum
IGF-I is significantly associated with measures of muscle strength and physical performance in men and to a lesser extent in women. In conclusion,
IGF-I is a pleiotropic
hormone that in older persons may positively affect the cardiovascular system, the central nervous system and physical function.