Blood Test Pinpoints Cause of Brain Injury in Newborns

Hypoxic-Ischemic Encephalopathy (HIE), also known as birth asphyxia, is a brain injury that occurs when a newborn's brain does not receive sufficient oxygen either before or just after birth. This condition is a major cause of death and disability in full-term babies worldwide, impacting about three million infants annually. Brain damage from oxygen deprivation can develop over a period ranging from hours to months, potentially impacting various brain areas and leading to diverse neurodisabilities such as cerebral palsy, epilepsy, and sensory impairments like deafness or blindness. South Asia, especially India, bears the brunt of this issue, with 60% of global HIE-related fatalities occurring in the country. Now, a blood test can pinpoint the underlying cause of brain injury in newborns and assist in making informed treatment choices.

In a study of infants with HIE, researchers from Imperial College London (London, UK) discovered that blood-based gene expression patterns can indicate the injury's origin and predict the infant's likelihood of responding to cooling treatment, a common method for treating brain injuries in babies. This advancement could pave the way for a simple blood test that rapidly diagnoses brain injuries in newborns, aiding in treatment decisions. The research included babies from both low and middle-income countries (LMICs) and high-income countries (HICs), revealing a stark contrast in gene expression between these groups, suggesting differing causes of brain injury.

Previous research, primarily in HICs, has shown that whole-body cooling can enhance recovery prospects for babies with HIE. This has led to its widespread adoption as standard practice in many HICs and some hospitals in South Asia. However, the most extensive study of its kind in LMICs, conducted by Imperial College London and its partners in India, Bangladesh, and Sri Lanka, had previously found that whole-body cooling might actually worsen outcomes and increase mortality risks in babies with HIE in these regions. The new study sheds light on why babies from different regions respond differently to cooling treatment and holds the potential for the development of a simple blood test to identify which infants will benefit from it. The research, a collaboration between Imperial College London and its South Asian partners, involved 35 Italian (a HIC) and 99 South Asian (from LMICs) newborns with HIE. Blood samples were collected soon after birth, and the infants were evaluated medically at 18 months.

About half of the babies in the South Asian group either passed away or developed severe disabilities, compared to a quarter in the Italian group. The researchers analyzed the correlation between gene expression at birth and outcomes at 18 months in both groups. They identified 1793 significant genes linked to adverse outcomes in the HIC group and 99 in the South Asian group, with only 11 significant genes common to both groups, but expressed differently. The researchers emphasized that these differences are not due to ethnic factors but rather socioeconomic ones. The type of chronic brain injury common in LMICs can also be found in impoverished areas of HICs. Conversely, in wealthier regions of LMICs, one might find more cases of acute brain injury, similar to those typically seen in HICs in this study.

“The key for clinicians, anywhere in the world, is to be able to identify which type of brain injury they are dealing with as soon as possible – and that’s something we’re currently working on,” said lead investigator, Professor Sudhin Thayyil from the Department of Brain Sciences at Imperial College London.

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Imperial College London