Insights Into Zika Virus and Birth Defect Reported
The pathogen appears to attack cells crucial to the developing fetal brain
By Dennis Thompson
FRIDAY, March 4, 2016 (HealthDay News) -- The Zika virus may cause the birth defect microcephaly by targeting certain brain stem cells and stunting their growth, researchers report.
Zika virus has been linked to microcephaly -- which results in abnormally small heads and brains -- since the current epidemic of the mosquito-borne pathogen began in Brazil last spring.
But, health experts have been at a loss to say whether or how the virus might cause the birth defect.
Now, laboratory studies have shown that Zika can infect a type of neural stem cell that gives rise to the cerebral cortex of the brain, researchers report in the March 4 issue of the journal Cell Stem Cell.
According to the researchers, the Zika virus flourished in lab dishes containing these stem cells, causing either cell death or disruption of cell growth.
"Although our study hasn't provided a direct link between Zika virus and microcephaly, we identify the direct cell targets of the virus and we show the virus can affect cell growth," said study co-author Zhexing Wen, a postdoctoral fellow at the Johns Hopkins University School of Medicine in Baltimore.
Since the Zika epidemic began, there have been more than 5,600 suspected or confirmed cases of microcephaly in Brazil, the epicenter of the outbreak, the World Health Organization has reported. And the virus is spreading in Latin America and the Caribbean.
The new findings "provide a potential mechanism [for] how a Zika virus infection can lead to poor brain growth and, therefore, microcephaly," said Dr. Sallie Permar, director of Duke University's Laboratory of Neonatal Viral Pathogen Immunity, in Durham, N.C.
The researchers said the stem cells targeted by Zika are called cortical neural precursors, and they spawn the brain cells that make up the cerebral cortex, the outer layer of the brain's gray matter that's largely responsible for higher brain functions.
The researchers tested Zika's effect on these cells using a Zika virus stock grown in mosquito cells, to replicate the means by which the virus infects human beings.