Zika Infection During Pregnancy Damages Placenta

Zika virus damages placenta
Zika virus damages a pregnant mother's placenta, an organ inside a woman's uterus that helps protect and care for a growing baby. Recent research describes how Zika virus infection in five pregnant rhesus monkeys caused placental tissues to become thickened and inflamed. As a result, the researchers saw less oxygen being transported across the placenta and to the baby. Decreased oxygen levels in a placenta can impair fetal development and ultimately the health of a baby after its born.

"The role of a placenta is to protect and provide nutrition to a growing baby for optimum health," said one of the paper's corresponding authors, Antonio Frias, M.D., an obstetrician and gynecologist at Oregon Health & Science University. "It's concerning how much damage the Zika virus can do to a placenta."

Zika virus affects placental oxygen reserve
Despite the seemingly normal fetal growth and persistent fetal-placenta-maternal infection, advanced non-invasive in vivo imaging studies reveal dramatic effects on placental oxygen reserve accompanied by significantly decreased oxygen permeability of the placental villi. The observation of abnormal oxygen transport within the placenta appears to be a consequence of uterine vasculitis and placental villous damage in ZIKV cases.

The paper's two other corresponding authors are associate professor Daniel Streblow, Ph.D., and assistant professor Alec Hirsch, Ph.D., both of whom lead molecular microbiology and immunology research at the OHSU Vaccine and Gene Therapy Institute. Streblow also leads pathobiology and immunology research at the Oregon National Primate Research Center and is a professor of molecular microbiology and immunology within the OHSU School of Medicine.

The research team used a non-invasive, in vivo MRI technique to evaluate oxygen levels inside the placenta and oxygen flow between mother and baby. They found that, in monkeys that were infected with Zika early in their pregnancies, the rate of oxygen transport through the placenta decreased about 10-fold.

The OHSU research team also determined the Zika virus can readily pass from mother to baby and remain in the baby long-term, leading to a chronic infection in utero. These findings may provide important insights into the mechanisms by which Zika virus causes disease during pregnancy.

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By better understanding how both mother and child become infected with and affected by the Zika virus, researchers can determine how to prevent its infection and disease. The OHSU research team is using the knowledge gained from this study to help develop a safe and effective Zika vaccine for use during pregnancy.

References:

1. Alec J. Hirsch, Victoria H. J. Roberts. Zika Virus Infection in Pregnant Rhesus Macaques Causes Placental Dysfunction and Immunopathology, Nature Communications https://www.nature.com/articles/s41467-017-02499-9

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Source-Eurekalert