Study: Mechanism Between Zika Virus, Birth Defects
Protein on fetal stem cells provides pathway for Zika; discovery might lead to infection-blocking drugs, researchers say
By Robert Preidt
WEDNESDAY, March 30, 2016 (HealthDay News) -- Scientists say they've discovered how the Zika virus might cause severe brain and eye birth defects.
The Zika outbreak in Brazil and other parts of Latin American and the Caribbean has coincided with a sharp increase in the number of babies born with microcephaly, which results in abnormally small heads and brains.
There has also been a rise in other brain and eye birth defects in countries affected by the Zika outbreak. But firm evidence of a link between the virus and these birth defects has been lacking.
In a new study, researchers at the University of California, San Francisco (UCSF), found that a protein the Zika virus uses to infect skin cells and cause a rash is also present in stem cells of the developing brain and retina of a fetus.
The so-called AXL protein sits on the surface of cells and can provide an entry point for Zika. Learning more about the link between Zika and AXL could lead to drugs to block Zika infection, according to the researchers.
The brain and eye birth defects occurring in areas with Zika outbreaks are "precisely the kind of damage we would expect to see from something that was destroying neural and retinal stem cells during development," said study senior author Dr. Arnold Kriegstein. He is director of UCSF's Center of Regeneration Medicine and Stem Cell Research.
"If we can understand how Zika may be causing birth defects, we can start looking for compounds to protect pregnant women who become infected," Kriegstein said in a university news release.
The study was published online March 30 in the journal Cell Stem Cell.
A mosquito-borne virus, Zika has been suspected of causing thousands of cases of microcephaly in Brazil.
While the bulk of Zika cases leading to microcephaly may occur via maternal infection during pregnancy, cases of sexual transmission from a man to his female partner have come to light, according to the U.S. Centers for Disease Control and Prevention.
Zika infection is usually a mild illness in adults, and many cases may occur without symptoms, experts say. However, because of the risk to babies, the CDC is advising that men with known or suspected infection with Zika refrain from sex -- or only have sex with a condom -- for six months after a diagnosis.