Seizure-induced alterations in cerebrovascular function in the neonate

Epileptiform seizures are most common during the neonatal period, affecting at least 0.3% of term neonates and more than 10% of preterm neonates. The adverse impact of neonatal seizures on the long-term neurological outcome has been well documented, but their cerebrovascular consequences are rarely emphasized. The cerebral blood flow is controlled by the interaction of the vascular and parenchymal cells forming the neurovascular unit via multiple mediator systems that have unique features in the newborn. Seizures drastically affect the neurovascular unit, resulting in (1) dramatic increases in brain metabolism and cerebral blood flow during the ictal period, (2) disruption of the blood-brain barrier, (3) an acute loss of cerebral pressure autoregulation, and (4) a delayed impairment of cerebrovascular reactivity to various stimuli. Furthermore, seizures frequently accompany and potentially aggravate a pre-existing cerebrovascular insult. This review summarizes the current knowledge on how seizures affecting various cells in the neurovascular unit result in the observed alterations in cerebrovascular function in the neonate.