Reversing Asthma Caused by Maternal Smoking

Asthma caused by maternal smoking in pregnancy may be able to be reversed, according to research published in the American Journal of Physiology — Lung Cellular and Molecular Physiology.

Researchers from Los Angeles Biomedical Research Institute (LA BioMed) hypothesized that perinatal nicotine exposure induced asthma could be reversed using homeostatic mesenchymal PPARγ agonist rosiglitazone (RGZ) — a diabetic medication which can stimulate cellular activity related to lung development – and they conducted this experiment on mice models.

The researchers noted that it is challenging to identify which chemicals in cigarettes are responsible for causing the asthma in newborns, as there are over 4,000 known chemicals in 1 cigarette. However, they commented that nicotine is known to affect fetal lung development, which can result in asthma. They used nicotine for this study to replicate its effects on pregnant mice and their newborns.

Pregnant rats received either placebo or nicotine from embryonic day 6 until term, and the treatment was continued up to postnatal day (PND) 21. The newborns were divided into groups, of which 1 group received placebo and the other received RGZ from PND 1 to PND 21.

Pulmonary function was assessed in the newborns at PND 21, where the researchers noted a significant increase in airway resistance and a decrease in airway compliance following methacholine challenge, a significant increase in acetylcholine induced tracheal constriction, and increased pulmonary and tracheal expression of the mesenchymal markers of contractility in the perinatal nicotine exposure group compared to the controls.

The researchers concluded that the RGZ treatment starting on PND 1 reversed the nicotine induced molecular and functional pulmonary effects and normalized the mice. Even when started postnatally, the authors wrote, perinatal nicotine exposure induced functional and molecular alterations in upper and lower airways can be reduced using PPARγ agonist RGZ.

“This is the first study to indicate that we could actually reverse the damage caused by exposure to nicotine during pregnancy,” the study’s corresponding author Virender K. Rehan, MD said in a press release. “Our earlier studies found this medication could prevent nicotine induced asthma when given during pregnancy. So we wanted to determine if we could actually reverse the lung and airway damage caused by nicotine, and we were able to do so.”