FRIDAY, Oct. 14, 2011 (HealthDay News) -- Elevated blood levels of a central nervous system protein can help doctors identify newborns with brain injuries caused by a lack of oxygen, according to a new study.
Monitoring levels of "glial fibrillary acidic protein," or GFAP, can also help doctors assess the effectiveness of a body-cooling therapy meant to prevent permanent brain damage in these infants, Johns Hopkins researchers said.
GFAP is specific to central nervous system cells that are crucial to the brain's structure.
The Hopkins team examined GFAP levels in 23 newborns who were born between 36 and 41 weeks' gestation and diagnosed with clinical oxygen deficiency to the brain (hypoxic-ischemic encephalopathy, or HIE), and compared them to babies without brain injury who were born at the same length of gestation.
HIE affects one to eight newborns per 1,000 U.S. births and can cause death, developmental delays, mental retardation or cerebral palsy.
The researchers found that GFAP levels were significantly higher in newborns with brain damage caused by oxygen deficiency during the first week of life.
"GFAP, a circulating brain-specific protein, is already measured in adult patients after stroke, cardiac arrest or traumatic brain injury in an effort to provide a prognosis for survival or brain damage," Dr. Ernest M. Graham, an associate professor of gynecology and obstetrics and a maternal-fetal medicine expert, noted in a Hopkins news release.
"Now we know this biomarker can serve as a valid predictor of disease, injury evolution and outcome in newborns," he added.
The highest GFAP levels were found in infants who had abnormal MRI brain scans and who underwent whole-body cooling, a three-day treatment that lowers the body temperature to 92.3 degrees Fahrenheit.
"Even though cooling therapy decreases the risk of death and neurological damage in newborns, it is far from perfect therapy, and its effectiveness varies from baby to baby," co-investigator Dr. Allen Everett, a pediatric cardiologist at the Johns Hopkins Children's Center, said in the news release.
"We don't really know for sure if during the 72 hours of cooling the brain is actually recovering. Biomarkers like GFAP can remove that uncertainty by telling physicians how the brain is responding, allowing them to tailor treatments accordingly," Everett explained.
One expert agreed that it's often "difficult" to spot newborns at risk.
"Diagnosis of neonatal encephalopathy and identification of eligible patients for hypothermia therapy can be challenging," said Dr. Elena Wachtel, director of the Neonatal Comprehensive Care Program at NYU Langone Medical Center and Bellevue Hospital Center in New York City.
Wachtel, who also directs the hospital's Hypothermia Program, said the new study results contain "very important and exciting data." She said it might "assist neonatologists to accurately identify eligible infants for hypothermia therapy, measure treatment efficacy and assist in providing prognostic information to the families." However, "further research is needed to determine if GFAP level can also predict the long-term neurodevelopmental outcome," Wachtel added.
The study was published in a recent issue of the American Journal of Obstetrics & Gynecology.
BirthInjury.org has more about hypoxic-ischemic encephalopathy.