Air pollution associated with high risks for birth defects

By Dr. Ananya Mandal, MDMay 29 2019

A study came from the Texas A&M University researchers that shows that the harmful particulate matter present in the atmosphere due to air pollution could lead to birth defects and even still births during pregnancy. They used animal models to prove their theories. The study results were published in the latest issue of the journal Proceedings of the National Academy of Sciences. The study was titled, “Adverse organogenesis and predisposed long-term metabolic syndrome from prenatal exposure to fine particulate matter.”

Air pollution associated with high risks for birth defects. Image Credit: Shaijo / Shutterstock

The World Health Organization says that 90 percent of the world population breathes in polluted air and 1 in 9 deaths is directly associated with harmful effects of air pollution leading around 7 million deaths yearly. The U. S. Environmental Protection Agency in 2018 said that one in three persons in the nation lives in regions with poor air quality conditions.

Researchers from the Colleges of Agriculture and Life Sciences and Geosciences, the Texas A&M Health Science Center collaborated with colleagues from University of California-San Diego to use female rats and study the effects of air pollution on the animals. They noted that ammonium sulphate was a common chemical found in the particulate matter in regions where there is air pollution. Large amounts of ammonium sulphate were found in major regions in Asia in China and India, and also in some areas in the United States for example the concentration was 51 percent in Houston and 31 percent in Los Angeles.

Lead author Renyi Zhang, Texas A&M Distinguished Professor of Atmospheric Sciences and the Harold J. Haynes Chair in Geosciences, in a statement said, “People typically believe that ammonium sulfate may not be terribly toxic, but our results show large impacts on female pregnant rats. It is unclear yet what is causing these profound effects, but we speculate that the size of nanoparticles or even the acidity may be the culprit.” He explained that this chemical is produced from burning coal which is the main source of energy for many of the developed and developing nations across the globe. Ammonium, he said comes from ammonia that comes from the emissions of agriculture, automobiles and animals. He said that this means that the present problem is a “major problem worldwide.”

The team took two groups of 10 female rats each who were between 0 to 18 days of their pregnancy. One group received clean air while the other received polluted air with “100 to 200 µg·m−3 of ultrafine aerosols of ammonium sulphate”. After the pups were born four of them from each group were nursed by the females while tissues were collected for analysis from the other pups. At day 21 of birth tissues were collected from these nursed pups (both males and females) and rest were fed a high fat diet until they were 105 days old. At this age their tissues were also collected for analysis.

Results showed that mothers exposed to ammonium sulphate had more still births, shorter pregnancies and lower birth weight of their babies. They also had raised glucose and fatty acids in their blood. There were fat deposits in their livers and around their arteries as well. The effects were replicated in their progeny as well.

Guoyao Wu, Texas A&M University Distinguished Professor and a co-author of this study said, “...our results show that prenatal exposure to air pollution may not dispose offspring to obesity in adulthood. Nutrition and lifestyle are likely major factors contributing to the current obesity epidemic worldwide.” Part of this study examined the effects of air pollution on the organs of the pups especially liver and the arteries and heart. There was fat deposits on thiese organs and when fet a high fat diet, there was an increased risk of obesity.

This study reveals that exposure to air pollution during pregnancy of the animals leads to lower survival rates of the fetus and offspring and also leads to preterm births. There is damage to the brains, hearts and other organs of the adult rats when exposed to these pollutants, write the authors. Zhang concludes, “While epidemiological studies have been widely adopted to assess the health effects of air pollution, these tend to yield little insight into adverse outcomes and long-term effects.” He said, “Furthermore, there is an absence of clinical recommendations for prevention and treatment of air pollution-related health issues. Our study has demonstrated that well-controlled exposure experiments using animal models offer major advantages for future air pollution control and are promising in the development of therapeutic intervention and treatment procedures.”

The study received funding support from Tier One Program (TOP) at Texas A&M, the Robert A. Welch Foundation, and the National Institute of Environmental Health Sciences.