JUN 01, 2016 08:41 AM PDT

New Work Suggests How Zika May Infect the Fetus

WRITTEN BY: Carmen Leitch
3 11 1071
While the current Zika virus outbreak is known to be transmittable from mother to fetus, the exact mechanism of this transfer is unknown. The route may involve multiple cell types through an indirect mode of delivery. A new study that was published in Cell Host & Microbe provides evidence for the theory that placental immune cells that have direct access to blood vessels of the fetus, called Hofbauer cells, are one of the cell types involved in this process.
"Our study indicates that this cell type may be a target for Zika virus in the placenta and replication in these cells may allow the virus to cross the placental barrier and enter the fetal circulation," said Rana Chakraborty, a pediatric infectious disease specialist at Emory University and one of the authors of the study.

"One group has recently discovered viral antigen in Hofbauer cells collected from placental tissue of a fetus that unfortunately died as a result of Zika virus infection," added senior author and Assistant Professor of Pediatrics at the Emory, Mehul Suthar.

In this work, the scientists looked at full-term placental tissue samples, donated by five women who had delivered by Caesarean section, to find cell types that could be vulnerable to infection from Zika virus. They infected the tissue with a strain of Zika virus that is currently spreading in Puerto Rico. Hofbauer cells are macrophages of the placenta that come from the mesenchymal stem cells of a developing fetus. Zika virus infection was found there in the Hofbauer cells. It was also revealed to a lesser extent in cells located in the middle layer of the placental barrier, called cytotrophoblasts. The team found that while the virus infects Hofbauer cells right away, the cytotrophoblasts only become infected after a couple of days.
Micrograph showing chorionic villi of placenta with Hofbauer cells
This work indicates that cytotrophoblasts are more permissive for Zika virus infection than the outer layer of the placenta, called the syncytiotrophoblast layer, previously shown to be impervious to Zika infection. The hypothesis is then that if the virus can cross the syncytiotrophoblast, the virus then has access to cells where it can penetrate and replicate.

One intriguing finding from the study was that the placental cells there were varying levels of viral replication over time in the five different samples. "A concept that is emerging is how host genetics or other non-viral factors, including nutrition and microbiota, influence your immune response," Suthar said. "What our study suggests is not everyone is predisposed to having the virus replicate in the placenta, but the full meaning of this needs to be explored further."

Hofbauer cells were identified more than a 100 years ago and yet there is very little information known about them. Overall, the Zika epidemic has certainly highlighted the dearth of facts we have about the human placenta and indicates that it’s an area ripe for more research.
 
Sources: Cell Host & Microbe, AAAS
 
About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
JUN 15, 2018
Genetics & Genomics
JUN 15, 2018
Why Blood Cells Originate in Bone
Adults typically produce billions of new blood cells every day.
JUN 18, 2018
Genetics & Genomics
JUN 18, 2018
Repairing Epigenetic Imbalance may Relieve Alzheimer's
When the balance between two enzymes was restored, it relieved symptoms of Alzheimer's in an animal model.
JUL 07, 2018
Genetics & Genomics
JUL 07, 2018
Cause of Gender Differences in Neurodevelopmental Disorders is ID'ed
Gender is a known factor in the development of neurological disorders. Now scientists think they know why.
JUL 19, 2018
Cell & Molecular Biology
JUL 19, 2018
Stopping Structural Changes in Collagen may Prevent Lung Fibrosis
Lung fibrosis is a serious condition that thickens tissues in the lungs and makes it hard to breathe.
AUG 05, 2018
Cell & Molecular Biology
AUG 05, 2018
The Major Health Risks Posed by Cipro
In recent years, studies have shown that a once-popular class of antibiotics can have life-threatening side effects.
AUG 14, 2018
Cell & Molecular Biology
AUG 14, 2018
A Totally New Look at the Cell's Powerhouse
Mitochondria don't only have their own DNA. They also have their own ribosomes.
Loading Comments...