Maternal high-fat diet may alter airway nerves in offspring, leading to asthma

New research points to a novel potential mechanism behind eating a high-fat diet during pregnancy and asthma in the offspring. This correlation has been previously documented, but the cause was unclear. The study is published ahead of print in the American Journal of Physiology-Lung Cellular and Molecular Physiology. It was chosen as an APSselect article for August.

"Our study reveals a novel potential mechanism, by which maternal high-fat diet increases the risk and severity of asthma in offspring."

Researchers from Oregon Health & Science University fed female mice either a high-fat diet (HFD) or a regular diet (RD). After eight weeks on their assigned diets, females in both groups were bred with males raised on a regular diet. Females continued their assigned diet until their pups were weaned. Once weaned, pups from both groups were fed a regular diet.

At different points in the offspring's development, researchers measured various metabolic factors, nerve development in their respiratory system, airway resistance and the presence of a molecule associated with asthma called substance P. Researchers also measured the offspring's responses to exposure to a chemical that triggered bronchoconstriction-;a narrowing of the airways.

Compared to offspring of RD mothers, both male and female offspring of HFD dams had greater body weight, despite eating a regular diet. They also had increased insulin resistance and more insulin in their blood than is healthy. In addition, male offspring of HFD mothers had an increased percentage of body fat and decreased lean mass.

At 16 weeks old, HFD offspring had longer nerves, more nerve branching and an increase in substance P associated with their nerves than the RD offspring. During the bronchoconstriction trials, HFD offspring also showed greater constriction of their airways and greater airway resistance, which are hallmark characteristics of asthma.

The researchers further demonstrated that the HFD offsprings' response to the bronchoconstriction trials was influenced by blocking the influence of the airway nerves. In these trials, the differences between groups went away. "These findings have important clinical implications and provide new insights into the pathophysiology of asthma," researchers concluded.