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Study bolsters link between Zika and microcephaly
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Researchers from three universities — Johns Hopkins, Florida State and Emory — exhibited the first evidence of a likely biological link between Zika and microcephaly by showing the virus directly targeted and infected cells involved in the brain’s development, according to their study published in Cell Stem Cell.
“Potentially, this could explain why there is a link to microcephaly, but there is a lot more work needed to show the direct causal effect,” researcher Guo-li Ming, MD, PhD, of Johns Hopkins’ Institute for Cell Engineering, said in a news release.
Meanwhile, in the New England Journal of Medicine, researchers reported that Zika virus infection in pregnant women was associated with other “grave outcomes” in fetuses — among them, fetal death.
‘Significant’ findings explain cell death
Ming and colleagues provided evidence that lab-grown human neural progenitor cells (hNPCs) were a “direct target” of Zika by showing that a strain of the virus serially passaged in monkey and mosquito cells “efficiently” infected the hNPCs. In turn, they were more likely to die and less likely to divide normally and create new brain cells. Infection spread to 65% to 90% of the cells within 3 days of infection, they reported.
Zika-infected hNPCs also were able to produce infectious Zika particles, the researchers found.
According to Ming and colleagues, their results “fill a major gap” in our knowledge about the primarily mosquito-borne virus and serve as an “entry point” in the race to discover a proven link with microcephaly.
“It’s significant because we’re literally the first people in the world to know this, to know that this virus can infect these very important cells and interfere with their function,” Hengli Tang, PhD, professor of biological sciences at Florida State, said in a news release. “Research is rewarding in general, but when you have something this timely and this clinically relevant, it’s extra satisfying because we’ll be helping people in the long run.”
Fetal abnormalities in 29% of cases
In addition to fetal death and fetal growth restrictions, a study in the New England Journal of Medicine reported that Zika virus infection in pregnant women in Rio de Janeiro led to placental insufficiency and central nervous system injury.
Researchers from Brazil and California enrolled 88 pregnant women who had developed a rash within the previous 5 days between September 2015 and February at the Oswaldo Cruz Foundation. Among them, 82% tested positive for Zika virus. Forty-two of the Zika-positive patients and all 16 of the Zika-negative women agreed to ultrasounds. Among them, abnormalities were detected in 29% of the fetuses of patients infected with the virus, and in none of the women who were not infected.
Two fetuses died, at 36 and 38 weeks, and in-utero growth was restricted — with or without microcephaly — in five fetuses. Researchers also observed ventricular calcifications or other central nervous system lesions, and abnormal amniotic fluid volume or cerebral or umbilical artery flow.
Eight of the women who had ultrasounds have given birth, and the ultrasound findings were confirmed in each, according to the researchers.
They said their findings offer “further support” linking Zika infection in pregnant women to abnormalities in their fetuses.
“Women with suspected or confirmed [Zika virus] infection should be monitored closely, with serial ultrasonography to evaluate for signs of placental insufficiency, given the risks of fetal death and intrauterine growth restriction,” they wrote. “The establishment of a scientifically credible link between [Zika virus] and abnormal congenital findings is of utmost importance for the effective and successful management of this epidemic in Brazil and worldwide.” – by Gerard Gallagher
Disclosure: The researchers report no relevant financial disclosures.
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