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The unborn baby: Healthy pregnant mothers exposed to air pollution from road traffic inhale toxic particles that may end up in the placenta
Sep28

The unborn baby: Healthy pregnant mothers exposed to air pollution from road traffic inhale toxic particles that may end up in the placenta

By Roberta Attanasio According to a recently published study, carbon and metal particles from road traffic, once inhaled, reach one of the many places where we would rather not find them—the unborn baby’s life support system, best known as placenta. Lead author Jonathan Grigg said: “Our study for the first time shows that inhaled carbon particulate matter in air pollution, travels in the blood stream, and is taken up by important cells in the placenta.” For the study, researchers analyzed placentas from 15 healthy non-smoking women, donated after the birth of their children. All women delivered healthy babies. However, they lived in an environment that exposed them to high levels of particulate matter originating from urban traffic. Indeed, the particles observed in the placental cells closely resemble—in size, shape and composition—those emitted by traffic-related sources or formed from them.   Photo by Camylla Battani on Unsplash Particulate matter (also called particle pollution) is a mixture of solid particles and liquid droplets found in the air, which come in many sizes and shapes and are made up of hundreds of different chemicals. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope. Some particles are emitted by construction sites, unpaved roads, fields, smokestacks or fires, but most form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries and automobiles. The researchers found—within the placental cells—not only carbon particles, but also particles containing carbon with a mixture of chemicals found in vehicle exhaust, such as iron, phosphorus, calcium, silica, aluminum, titanium, chromium, and cerium, which arise from fuel and oil additives. How did these particles get into the placental cells? Particles present in air pollution are inhaled, and then from the lungs translocate to distant organs through the blood stream. Macrophages and trophoblasts— the primary resident phagocytes in the placenta—pick them up. Phagocytes are cells of the innate immune system also known as the “big eaters”—they engulf the particles with the aim of “cleaning up” the placenta. Lisa Miyashita, a study co-author, said: “We have thought for a while that maternal inhalation could potentially result in pollution particles traveling to the placenta once inhaled. However, there are many defense mechanisms in the lung that prevent foreign particles from traveling elsewhere, so it was surprising to identify these particles in the placental cells from all 15 of our participants.” Why is it worrisome to find particulate matter in placental cells? “The placenta is a distinctive and...

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