Researchers have found that exposure to environmental pollution during pregnancy increases asthma risk in children, grandchildren and great grandchildren. To arrive at their findings, the team studied three generations of mice born to mothers exposed to either diesel exhaust particles or urban air particle concentrate during pregnancy.
The team compared cells from the lungs of the first, second and third generations of offspring to three generations of control offspring that were not exposed to the pollutants. They found that all generations of mice from mother exposed to diesel exhaust particles had an abnormal increase in a type of immune cell, a common marker for allergy.
It was also found that mice whose mothers were exposed to pollutants had elevated levels of interleukin proteins that are involved in regulating the immune system, which are a marker of asthma risk. These risks were however found to be more prominent in the first and second generations, implying that inherited risk factors reduces in further generations.
Their findings reveal that exposure to environmental pollutant before birth caused epigenetic changes in the offspring’s DNA that affect how genetic code is used. This is known as DNA methylation. The team found that atypical DNA methylation led to transgenerational asthma risk due to abnormal changes in a type of immune cell called dendritic cells. They found that these cells play a crucial role in the development of asthma later in life.
According to Alexey Fedulov, corresponding researcher on the study, findings of this study may help doctors begin to recognize asthma not only as an inflammatory disease but also, to a large extent, an epigenetic disease, which may allow the invention of new treatment strategies.