Malnutrition linked with increased risk of Zika birth defects

The severity of Zika virus-related deformations in babies has been shown to be affected by environmental factors such as maternal nutrition

Congenital Zika Syndrome (CZS) refers to a collection of developmental malformations associated with Zika virus (ZIKV) congenital infection. This syndrome includes devastating conditions that have a huge impact on the rest of the life of the individual and their family, such as smaller (microcephaly) and unfolded (lissencephalic) brains, retinal abnormalities, enlarged ventricles of the heart, a lack of the inter-hemispheric connections and calcifications in the brain.

Brazil has been widely affected by ZIKV, but ~75% of CZS have been found in the socio-economically disadvantaged region of the Northeast.

In a new study, researchers from the University of Oxford and the Federal University of Rio de Janeiro have found that this rise in cases of CZS is linked to poor diet among the infants’ mothers.

Professor Zoltán Molnár of the University of Oxford’s Department of Physiology, Anatomy & Genetics, who participated in the study and has a long-term collaboration with the lead author Associate Professor Patricia Garcez of the Federal University of Rio de Janeiro Brazil partially supported by the Medical Research Council and Royal Society, said: ‘We knew that areas of Brazil with the lowest socioeconomic status had the highest level of developmental impairment in babies due to CZS, which is why we looked at the possible link between ZIKV and one of the potentially most important co-factors, nutrition.

‘This study showed that developmental impairment caused by ZIKV congenital infection is made much worse by environmental co-factors, specifically diets poor in protein, which explains why the devastating effects of CZS vary across ZIKV endemic regions.’

The link between Zika virus infection and the CZS has been demonstrated in previous studies, which helped researchers understand how the infection affected brain growth and development of blood vessels. These showed that ZIKV infects the cells that develop into the brain and alter genes and proteins related to the normal cell cycle and blood vessel development.

The current study also used a mouse model to replicate the effects of Zika infection in mice that had a low-protein diet, and found that several of the pathological signs found in humans appeared in the undernourished mice in a similar way.

Professor Molnár added: ‘When we replicated the effects seen in humans who had poor diets in mice we saw similar effects in the foetuses, such as placental damage as well as poor embryonic body growth and a reduction in brain size of newborns born to undernourished pregnant mouse.

‘The mouse mothers were clearly less able to fight against ZIKV, which was shown by a robust and persistent ZIKV infection in the spleens of undernourished mothers, in contrast to healthy mice. Our undernourished mouse model helped us to identify the cellular mechanisms that are responsible for the differences in humans.’

‘Improving diet alone will not protect against ZIKV infections, but it can determine the severity of the CZS.

‘While we need more work to translate these findings to human disease, our mouse model helped us to identify significant differences in the regulation patterns of key molecular pathways, and particular genes identified within developing brains reflect how a poor nutritional status increases the adverse effects of ZIKV infection.’

The study was partially funded by a joint MRC Grant between Professor Zoltán Molnár of the University of Oxford and Associate Professor Patricia Garcez of the Federal University of Rio de Janeiro.

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Notes to editors

Congenital Zika Syndrome is associated with Maternal Protein Malnutrition – Sciences Advances AAAS

For further information, please contact:
Chris McIntyre in the University of Oxford press office at [email protected] or on +44 (0)1865 270 046

Oxford University’s Medical Sciences Division is one of the largest biomedical research centres in Europe, with over 2,500 people involved in research and more than 2,800 students. The University is rated the best in the world for medicine and life sciences, and it is home to the UK’s top-ranked medical school. It has one of the largest clinical study portfolios in the UK and great expertise in taking discoveries from the lab into the clinic. Partnerships with the local NHS Trusts enable patients to benefit from close links between medical research and healthcare delivery.

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