PITTSBURGH – Obesity-mediated oxidative stress not only plays an important role in the pathogenesis of vascular disease and non-alcoholic liver disease, but it may directly affect lung health.

The accumulating evidence supporting a possible link between obesity and asthma has prompted researchers to address the question of how cytokine imbalances and metabolic abnormalities seen in obesity may affect the lung. Visceral adipose tissue is known to be metabolically active and to secrete a multitude of hormones and cytokines. However, the main targets for these effects were thought to be the liver and the cardiovascular system.

The chronic generalised inflammatory changes occurring in obesity do more than just perpetuate the progression of atherosclerosis, according to Dr Fernando Holguin from the University of Pittsburgh Medical Center and his colleagues.

They write in the Journal of Applied Physiology: “Obesity is associated with increased systemic and airway oxidative stress, which may result from a combination of adipokine imbalance, comorbidities and reduced antioxidant defences.”

However, the combination of obesity and asthma, both of which are chronic inflammatory diseases, does not necessarily have a synergistic effect leading to even greater oxidative stress. Studies looking at oxidative stress biomarkers to date have included only stable asthma patients and it is possible that the interaction of oxidative stress between obesity and asthma is not readily detectable under basal conditions.

Therefore, according to Dr Holguin, obesity-mediated oxidative stress, which may affect the lung function of asthma patients by increasing airway inflammation and reducing the effectiveness of inhaled corticosteroids, should be examined during exposure to an aggravating factor or during periods of asthma exacerbation.

“Understanding whether obesity-mediated oxidative stress plays a mechanistic role in the association between obesity and asthma will help in the formation of public health policies and increase our capacity to develop therapeutic interventions that improve the life of obese asthmatics,” he adds.

Photo Credit: Patrick T Power (Flickr)