Researchers from Imperial College London have shown that a blood test can identify the underlying cause of brain damage in newborns.
Their study looked at babies with a type of brain damage caused by hypoxia – a lack of oxygen. It was found that gene expression patterns detectable in the blood can indicate the cause of the injury and tell doctors whether the newborn is likely to respond to cooling treatment, commonly used to treat brain damage in infants .
The results, published in the journal Open JAMA Networkcould eventually lead to a simple test to quickly diagnose brain damage in newborns and aid treatment decisions.
The study included babies from low- and middle-income countries (LMICs) as well as high-income countries (HICs). There was a dramatic divergence in gene expression between the two groups, suggesting a different underlying cause of the brain damage.
Lead investigator Professor Sudhin Thayyil from the Department of Brain Sciences at Imperial College London explains: “Although cases of brain damage in babies may seem similar, they can be very different in terms of how they are happening, as our study shows. The gene expression patterns we observed in LMIC babies were similar to those that would be seen in people with sleep apnea, suggesting that they experienced intermittent hypoxia in the uterus and at birth.
“We believe this is caused by multiple chronic stresses during pregnancy, such as poor diet or infection, as well as the normal process of labor and uterine contractions, which lead to further hypoxia and ultimately brain damage to the baby.
“On the other hand, gene expression patterns in babies born with ICH suggest a single, acute cause of brain injury, for example complications during delivery such as maternal bleeding, leading to a sudden drop in levels oxygen in the fetal blood.”
A factor in neonatal mortality
Hypoxic-ischemic encephalopathy (HIE) is a type of brain injury sometimes called birth asphyxia, which occurs when a baby’s brain does not receive enough oxygen before or shortly after birth.
Globally, HIE is a leading cause of death and disability in full-term babies, affecting approximately 3 million babies each year. Following a lack of oxygen, brain damage can develop within hours or even months and affect different regions of the brain, leading to various potential neurological impairments such as cerebral palsy, epilepsy, deafness or blindness.
South Asia, and particularly India, has the highest burden of disease, with this country accounting for 60% of all HIE-related deaths worldwide.
Previous studies, mainly conducted in high-income countries (HIC), have shown that whole-body cooling treatment can improve outcomes for babies with HIE. As a result, this method has become standard practice in many HICs and is also used in some hospitals in South Asia.
However, in the largest study of its kind in low- and middle-income countries (LMICs), Professor Thayyil and colleagues in India, Bangladesh and Sri Lanka previously showed that whole-body cooling actually worsens outcomes in babies with HIE and may even have increased mortality risk.
The new study helps explain the reason behind this difference in treatment response between the two groups of babies and could eventually lead to a simple test to assess which babies are likely to benefit from cooling treatment.
Comparison of gene expression
The study, led by Imperial and its South Asian partners, included 35 babies born with HIE in Italy (an HIC) and 99 babies from LMICs in South Asia (India, Sri Lanka and Bangladesh). . Blood samples were taken shortly after birth and the babies were medically examined at 18 months of age.
In total, around half of the babies in the South Asian cohort died or developed serious disabilities, compared to a quarter in the Italian cohort.
The researchers looked for correlations between gene expression at birth and outcomes at 18 months in both cohorts. They found 1,793 significant genes associated with adverse outcomes in the HIC cohort and 99 significant genes associated with adverse outcomes in the South Asian cohort. There were only 11 significant genes common between the cohorts, but they were expressed in opposite directions (either on in one cohort and off in the other, or vice versa).
Study co-author Professor Swati Manerkar of Lokmanya Tilak Municipal Medical College in Mumbai, India, comments: “We expected to see some differences in gene expression between babies in the cohorts, but not such a dramatic divergence. This clearly shows that we are seeing very different causes of brain damage between the two groups, with different characteristics that also help to explain why some babies respond to cooling and others suffer from it.
Guide treatment decisions
The researchers emphasize that the differences between cohorts are not linked to ethnicity, but rather to socio-economic factors. The type of chronic brain injury commonly seen in LMICs is also likely to be present in deprived areas of HICs. Similarly, among wealthier populations in LMICs, one might expect to see more cases of acute brain injury of the type seen primarily in HICs in the present study.
Professor Thayyil comments: “The key for clinicians everywhere is to be able to identify as quickly as possible the type of brain injury they are facing – and this is something we are working on Currently. »
More information:
Sudhin Thayyil et al, Whole body hypothermia, brain magnetic resonance biomarkers and outcomes in neonates with moderate or severe hypoxic-ischemic encephalopathy born in tertiary care centers compared to other facilities, Open JAMA Network (2023). DOI: 10.1001/jamanetworkopen.2023.12152
Provided by Imperial College London
Quote: Blood test could reveal cause of brain damage in newborns (February 2, 2024) retrieved February 2, 2024 from
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