According to a study conducted by Texas A&M University, exposure to pollution during pregnancy can have many adverse effects in infants and children that can even carry over into adulthood.
The results of the study have been published in the journal “Antioxidants”. Exposure to air pollution is associated with an accelerated risk of low birth weight, premature birth, and risk of developing asthma later in life. This is largely due to the rapid rate of growth and development of the fetus. However, exactly how pollutants have these effects and the roles of genes related to immune function and stress response have not been fully understood.
Natalie Johnson, PhD, associate professor at the Texas A&M School of Public Health, along with Carmen Lau, DVM, Jonathan Behlen and others exhibited animal models modified to lack the Nrf2 gene and unmodified animal models for pollution particulate like that found in diesel exhaust. They then assessed the effects on litter size, birth weight and immune markers found in the lung and liver tissues of newborn offspring.
Particle pollution is divided into three categories according to particle size, coarse particles, fine particles and ultrafine particles. Fine particles less than 2.5 microns in diameter and ultrafine particles less than a tenth of a micron in diameter are of most concern.
Researchers have found associations between fine particle pollution and increased risks of respiratory disease, but less work has been done on ultrafine pollutants, and no health standards currently exist for this smaller category. The small size of ultrafine particles means that they can penetrate deeper into the airways, which can make them even more dangerous to health than fine particles.
The Nrf2 gene is known to affect immune function and stress response in adults, but research on the effects of this gene in infants and children has been less explored. To better understand the role of Nrf2 during development and clarify the impact of ultrafine particles on health, researchers exposed both unmodified animal models and those with knocked out Nrf2 genes to fresh air. and filtered and air containing ultrafine particles like those found in diesel exhaust, a common pollutant in urban areas. The researchers monitored weight gain in pregnant animal models in all four groups and recorded litter size and offspring birth weight.
There were no statistically significant differences in weight gain in animal models of the four groups during pregnancy. Similarly, there were no noticeable differences in litter size. However, Nrf2-deficient offspring had lower birth weights than their unmodified counterparts, with the greatest effects in Nrf2-deficient animal models exposed to pollution. Pollution exposure had no noticeable effect in unmodified animal models, which may indicate that Nrf2 plays a protective role during pregnancy.
The researchers also analyzed lung and liver tissue from the offspring to measure differences in certain immune markers and the expression of genes related to the oxidative stress response. They found significant differences in immune markers in the Nrf2-deficient offspring, indicating a change in immune function in these models. These results indicate that the absence of a functional Nrf2 gene is the main contributor to the differences between the groups.
These results are consistent with other studies that have found associations between Nrf2 deficiency and certain chronic diseases. For example, previous research found that Nrf2-deficient adult animal models were more likely to develop autoimmune diseases. Although more work remains to be done, this study demonstrates that the absence of a functional Nrf2 gene affects prenatal growth in animal models, particularly when exposed to air pollution by ultrafine particles in womb.
These findings could point to a possible mechanism by which ultrafine particles may affect placental function and prenatal health. This highlights the need for further research into the roles of genes in immune and stress responses and how these genes interact with environmental factors. The research also reinforces the importance of setting health standards for ultrafine particle pollution, which appears to have serious effects on prenatal and neonatal health and development.
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Posted: Sunday April 10th 2022, 1:32 PM IST