Ghrelin is secreted in the body as a part of the process of hunger, and increased amounts in circulation have a range of sweeping effects on the operation of metabolism. It has been proposed that some portion of the long-term health benefits of calorie restriction and intermittent fasting arise because there are longer periods of hunger and thus longer periods in which there is more circulating ghrelin. For example, ghrelin has been shown to reduce inflammation and promote the development of new immune cells, among many other changes. So read this research in the broader context; I note it because it should be of interest to those who practice dietary restriction of one form or another, not because I believe that the approach here is necessarily going to result in a useful form of therapy:
A new study by a team of researchers suggests that the appetite-regulating hormone ghrelin could be used clinically for the early treatment of critical limb ischemia (CLI), an advanced form of peripheral artery disease. CLI is the severe obstruction of blood flow to the extremities that often requires major amputations and in half of all cases leads to death within five years. Its leading risk factors are diabetes, obesity and age. Using a mouse model of CLI, researchers showed that administering ghrelin daily over two weeks markedly improved blood flow in affected limbs. They found that ghrelin promoted growth of new structurally and functionally normal blood vessels, improved cell survival, and decreased tissue fibrosis.
The findings are exciting as currently there are no drugs treatments for CLI and other techniques are effective in only half of the cases. "Our team has previously shown that ghrelin showed promise for treating the presently incurable lung disease known as pulmonary hypertension, which is caused by blood vessels becoming progressively blocked. This prompted us to investigate whether ghrelin might have a similar effect in CLI." The researchers also studied ghrelin's action at the molecular level in tissue with restricted blood supply and identified that the hormone modulated downstream signalling cascades involved in new blood vessel growth and cell survival.