IGF-1 ameliorates the blood brain barrier disruption induced by the neonatal hypoxia-ischemia

Neonatal hypoxic-ischemic encephalopathy (HIE) disrupts the blood-brain barrier (BBB) and destroys nascent vessels, thereby amplifying parenchymal loss and chronic neurological disability. Restoring a competent cerebrovasculature is therefore a critical therapeutic goal. Insulin-like growth factor-1 (IGF-1) is already recognized as a neurotrophic factor whose circulating levels correlate with HIE severity and long-term outcome, yet its capacity to drive vascular repair after the insult remains incompletely defined. This study investigated the role of exogenous IGF-1 in BBB repair in neonatal mouse post HI. Our results showed that IGF-1 receptor (IGF-1R) existed on the surface of endothelial cells, which was further upregulated in response to HI challenge. Administration of exogenous IGF-1 apparently attenuated BBB disruption concomitant with a marked enhancement of angiogenesis within the injured cerebral parenchyma. On the contrary, inhibition of the IGF-1R abrogated IGF-1-mediated proangiogenic effects. More importantly, activation of the IGF-1/IGF-1R axis promotes revascularization dependent on upregulation of AKT/eNOS signaling. All together, these findings indicate that IGF-1/IGF-1R axis may represent a potential therapeutic target for blood-brain barrier repair in neonatal HI injury.