In a recent study published online, physician-scientists at Oregon Health & Science University Doernbecher Children's Hospital have challenged a view long held by pediatric neurologists about brain injury in the preterm infant.
They report that ischemia or reduced blood and oxygen flow to the developing brain do not cause an irreversible loss of brain cells, but rather disrupts their ability to mature fully. This discovery is likely to open up exciting new approaches for potential therapies that promote regeneration and repair of the premature developing brain.
More than 65,000 premature babies are born in the US every year. Those children who survive preterm birth typically go on to suffer from a wide range of life-long disabilities, including impaired walking due to cerebral palsy.
By the time they reach school age, between 25-50% of children born prematurely usually also suffer from a wide range of learning disabilities, social impairment and attention deficit disorders.
These findings suggest that pediatricians need to focus more attention on developing the right interventions at the right time to promote brain cell maturity and reduce the serious impact of preterm birth on brain development.
Studies in preterm fetal sheep also show that disturbances in brain blood flow harm the developing brain. Pioneering new MRI studies looked at the cerebral cortex, the "thinking" part of the brain, which controls complex tasks involved with learning, attention and social behaviors. Not surprisingly, these skills are frequently impaired in children who survive preterm birth.
Specifically, researchers observed how injury to brain cells in the cerebral cortex of fetal sheep evolved and noticed that more brain cells were being packed into a smaller brain volume. In other words, these sheep brain cells were smaller because they weren't maturing fully.
In another related study, investigators at The Hospital for Sick Children and the University of Toronto studied 95 premature infants using MRI and found that impaired infant growth was the strongest predictor of MRI abnormalities. This suggests that interventions to improve infant nutrition and growth may improve cerebral cortical brain development.
These studies are very promising for the future for preterm babies with brain injury, because they show that ischemia does not permanently destroy cerebral cortex brain cells and suggest that improved early infant nutrition may improve cognitive outcome.
Together, these findings are likely to both challenge and change the way neurologists think about the diagnosis and treatment of children born prematurely.