First evidence that soot from polluted air reaches the placenta

Evidence for tiny carbon particles, typically created by the burning of fossil fuels, was found for the first time in placentas, according to a new study presented today (Sunday) at the International Congress of the European Respiratory Society.

Previous research has shown links between the exposure of pregnant women to air pollution and premature birth, low birth weight, infant mortality and respiratory problems in children.

The new study adds to existing evidence on the dangers of pollution for unborn babies and suggests that when pregnant women breathe in polluted air, soot particles can reach the placenta via the bloodstream.

The work was presented by Dr. Norrice Liu, pediatrician and clinical researcher, and Dr. Lisa Miyashita, postdoctoral researcher, both members of Professor Jonathan Grigg's research group at Queen Mary University in London, UK. -United. Dr. Miyashita said, "We have known for some time that air pollution affects fetal development and can continue to affect babies after birth and throughout their lives.

"We were interested to see if these effects could be due to pollution particles moving from the mother's lungs to the placenta." Until now, there was very little evidence that inhaled particles enter the bloodstream. by the lungs. "

The researchers worked with five pregnant women living in London who planned to deliver by caesarean section at the Royal London Hospital. They were all nonsmokers with a single pregnancy and each gave birth to a healthy baby. The women all allowed researchers to study their placenta after delivery.

The researchers focused on particular cells called placental macrophages. Macrophages exist in many different parts of the body. They are part of the immune system and work by including harmful particles, such as bacteria and pollution particles. In the placenta, they also help protect the fetus.

The team studied a total of 3,500 placental macroscopic cells from the five placentas and examined them under a powerful microscope. They found 60 cells that contained between them 72 small black areas that researchers think are carbon particles. On average, each placenta contained about five square micrometers of this dark substance.

They then further studied placental macrophages from two placentas with the help of an electron microscope and found materials that they thought were tiny particles of carbon.

In previous research, the team had used the same techniques to identify and measure these soot particles in macrophages in the airways. Dr. Liu added, "We thought that examining macrophages in other organs could provide direct evidence that inhaled particles were coming out of the lungs to other parts of the body.

"We did not know if we were going to find particles and if we found them, we were only expecting to find a small number of placental macrophages that contain these soot particles." That's because most of they should be engulfed by macrophages in the airways, especially larger particles, and only a minority of small particles would enter the circulation.

"Our results provide the first evidence that inhaled pollution particles can move from the lungs to the circulation and then to the placenta.

"We do not know if the particles we found could also move into the fetus, but our evidence suggests that this is actually possible.We also know that particles do not need to enter the baby's body to have an adverse effect, because if they have an effect on the placenta, this will have a direct impact on the fetus. "

Professor Mina Gaga is President of the European Society of Pneumology and Medical Director and Chief of Respiratory Service of the Athens Hospital, Greece, and did not participate in the study. She said: "Previous research shows that pregnant women living in polluted cities are more prone to pregnancy problems such as restricted fetal growth, premature birth, and low birth weight." Below-limit pollution annual report recommended by the European Union.

"This new research suggests a possible mechanism of how babies are affected by pollution while theoretically protected in the uterus.This should educate clinicians and the public about the harmful effects of air pollution in pregnant women. .

"We need tougher policies for cleaner air to reduce the impact of pollution on global health because we are already seeing a new population of young adults with health problems."

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