Dirty Air

Researchers study how combustion-derived pollution can change metabolism, epigenetic makeup in the womb

Gestational exposure to combustion-derived particular matter can lower energy expenditure at least in part through alterations to mitochondrial metabolism, according to a new study from researchers at Le Bonheur Children’s and the University of Tennessee Health Science Center.

The study, published in the American Journal of Physiology, Endocrinology and Metabolism, found that pregnant mice exposed to particulate pollution had larger pups – who stayed large throughout life – than pups born to mothers who weren’t exposed to pollutants. Surprisingly, hose large pups also ate less food than their control counterparts, said Stephania Cormier, director of the Pediatric Asthma Research Program and Plough Foundation Chair of Excellence in Pediatrics at Le Bonheur and UTHSC.

Cormier believes this work will translate to humans, particularly those in industrialized countries with high combustion pollution. It could also explain the rapid increase of obesity and diabetes among humans in industrialized countries – a rate that far outpaces evolutionary changes. Her goal is to learn more about how obesity and airway dysfunction correlate – and eventually develop therapeutics to treat the condition.

The increased body size observed in mice exposed to the combustion-directed particular matter was associated with reduced physical activity and lower energy expenditure. The reduced energy expenditure in pups indirectly exposed to the pollutants was associated with reductions in skeletal muscle, mitochondrial DNA copy number, lower mRNA levels of electron transport genes, and reduced citrate synthase (a marker of cellular oxidative capacity) activity.

Researchers also believe exposure increased oxidated stress and eventually changes the mitochondrial metabolism in the skeletal muscle of the pup. Cormier now wants to determine if exposure has transgenerational effects – and whether mitochondrial changes in the body can change genetic makeup and affect children for generations to come.