Circulating biochemical markers of brain damage in infants complicated by ischemia reperfusion injury.

Hypoxia-ischemia constitutes a risk in infants by altering cerebral blood flow regulatory mechanisms and causing loss of cerebral vascular auto-regulation. Hypotension, cerebral ischemia, and reperfusion are the main events involved in vascular auto-regulation leading to cell death and tissue damage. Reperfusion could be critical since organ damage, particularly of the brain, may be amplified during this period. An exaggerated activation of vasoactive agents of calcium mediated effects could be responsible for reperfusion injury, which, in turns, leads to cerebral hemorrhage and damage. These dramatic phenomena represent a common repertoire in infants complicated by perinatal acute or chronic hypoxia or cardiovascular disorders treated by risky procedures such as open heart surgery and cardiopulmonary by-pass (CPB). To date, despite accurate perinatal and intra-operative monitoring, the post-insult period is crucial, since clinical symptoms and monitoring parameters may be of no avail and therapeutic window for pharmacological intervention (6-12 hours) may be limited, at a time when brain damage is already occurring. Therefore, the measurement of circulating biochemical markers of brain damage, such as vasoactive agents and nervous tissue peptides is eagerly awaited in clinical practice to detect high risk infants. The present review is aimed at investigating the role as circulating biochemical markers such as adrenomedullin, a vasoactive peptide; S100B, a calcium binding protein, activin A, a glycoprotein; neuronal specific enolase (NSE), a dimeric isoenzyme; glial fibrillary acid protein (GFAP), a astroglial protein, in the cascade of events leading to ischemia reperfusion injury in infants complicated by perinatal asphyxia or cardiovascular disorders requiring risky therapeutic strategies such as CPB and/or extracorporeal membrane oxygenation.