Particulate matter is considered a serious environmental threat to human health - and its effects begin earlier than previously assumed. An international research collaboration between the University of Lund in Sweden and the Medical University of Graz has shown for the first time that particulate matter from urban traffic can not only change the structure of the placenta, but can also affect the function of its immune cells. Even brief contact with PM2.5 particles - i.e. particularly fine air pollutants - led to measurable changes in placental tissue in the experiment.
Destroyed cell structures and inflammatory immune reactions
The placenta takes on central tasks during pregnancy: It supplies the unborn child with nutrients and oxygen, regulates the metabolism between mother and foetus and ensures an inflammation-free, protective environment in the womb through specialized immune cells. In order to better understand how air pollutants could affect these functions, the research team used a highly specialized experimental model - the so-called ex vivo dual placental perfusion, in which placental tissue can be examined immediately after birth under controlled conditions.
Analysis of the samples using transmission electron microscopy showed that even brief contact with PM2.5 particles, the particularly small particulate matter from urban traffic, leads to significant damage in the placental tissue. Collagen fibers, which give the tissue stability, and mitochondria, which are crucial for the energy supply of the cells, were affected. "The reaction of the immune cells in the placenta was particularly striking: they switched from a normally anti-inflammatory to a pro-inflammatory state - a pattern that is also observed in pre-eclampsia, a serious pregnancy disease with potential risks for mother and child," describes molecular biologist Birgit Hirschmugl from the Medical University of Graz.
A possible risk factor for pre-eclampsia
Our data suggest that air pollutants not only increase the risk of respiratory and cardiovascular diseases, but also represent a previously underestimated risk for pregnant women and their unborn child," emphasizes Christian Wadsack , head of the Graz research group. The changes in the placenta could therefore contribute to the development of pre-eclampsia, a condition that can be associated with high blood pressure, organ damage and growth retardation in the foetus.
Scientific progress with social relevance
The findings underline the urgency of political and social measures to reduce air pollution - especially in urban areas. At the same time, they show the importance of intensive research into the placenta as a central organ of pregnancy.