Researchers have made a new discovery, which entails that Zika virus is capable of infecting and imitating immune cells present in the placenta. This discovery can actually shed light on the way virus manages to get transferred via the placenta of a pregnant woman, thereby infecting the developing brain cells in her fetus. The senior author of the study and an Assistant Professor of Pediatrics at Emory University School of Medicine, Mehul Suthar, PhD, stated that the outcomes validate the incomplete proofs that are provided by pathology case reports.
Suthar added that it has been known that placenta is getting infected by Virus, but very limited information was available on to the location of the virus imitation and the kind of cell it was replicating. A team of scientists headed by Suthar and Pediatric Infectious Disease Specialist Rana Chakraborty, MD, detected Zika virus infecting placental macrophages known as Hofbauer cells, in cell culture.
Second kind of placental cell that can be infected by the virus is cytotrophoblasts. It was recently revealed by other scientists that a more varied type of placental cell, called yncytiotrophoblasts, as compared to cytotrophoblasts, displayed higher resistance towards Zika infection. The researchers collected the sample of cells to conduct the analysis from full-term placentae, which were voluntarily provided by women, who delivered though Cesarean section.
The analysis revealed variation in level of viral infection among the various samples. This reveals that placentae of certain females might me more prone to viral infections as compared to others. Suthar revealed that Zika virus is not transmitted to the fetus of every infected female.
“Host genetics and non-viral factors, including nutrition and microbiota, as well as timing may be influencing infectivity. A better understanding of these factors could allow the design of preventive measures, and eventually antiviral therapies”, said Suthar.
According to a story published on the topic by UPI News, New research seems to shed light on how the Zika virus infects, but doesn’t kill, placenta cells. The mosquito-borne virus can cause severe birth defects in babies whose mothers are exposed to Zika during pregnancy, but scientists don’t know exactly how that happens. “Our results substantiate the limited evidence from pathology case reports,” said senior author Mehul Suthar, an assistant professor of pediatrics at Emory University School of Medicine, in Atlanta.
The Zika virus used in the study is the strain circulating in Puerto Rico. The researchers said it’s closely related to the strain in Brazil, where the virus-related birth defects became apparent last spring. The researchers found that Zika can replicate in immune cells from the placenta without killing them. They said this may explain how the virus can pass through the placenta of a pregnant woman and infect developing brain cells in her fetus.
The level of viral replication varied markedly from donor to donor, which hints that some women’s placentae may be more susceptible to viral infection than others, they said. “Not every pregnant woman who is infected by Zika transmits the virus to her foetus. Host genetics and non-viral factors, including nutrition and microbiota, as well as timing may be influencing infectivity,” said Suthar. “A better understanding of these factors could allow the design of preventive measures, and eventually antiviral therapies,” according to a recent DNA News report.
This is thought to be because of the protective role of the placenta, which separates the circulatory systems of the mother and foetus, they said. “Zika may be unique in its ability to infect placental cells and cross the placental barrier, in comparison with other flaviviruses,” said Suthar. “It is still possible that disruption of the placental barrier – as seen in a recent case report – or antibody-mediated mechanisms are contributing to placental infection by Zika virus.”
A report published in News Medical informed, “Scientists led by Suthar and pediatric infectious disease specialist Rana Chakraborty, MD found that Zika virus could infect placental macrophages, called Hofbauer cells, in cell culture. The virus could also infect another type of placental cell, called cytotrophoblasts, but only after a couple days delay and not as readily. Other researchers recently reported that syncytiotrophoblasts, a more differentiated type of placental cell than cytotrophoblasts, are resistant to Zika infection.”
For viruses related to Zika (flaviviruses) such as dengue virus, West Nile virus and yellow fever virus, it is rare for the infection to be transmitted from mother to fetus. This is thought to be because of the protective role of the placenta, which separates the circulatory systems of the mother and fetus. “Zika may be unique in its ability to infect placental cells and cross the placental barrier, in comparison with other flaviviruses.”