Scientists create a new model for cigarette smoking research
Orange County, CA - February 11th 2017 - To study the effects that smoking has on normal and diseased human airways, researchers from Harvard University have combined a robot designed to take drags from cigarettes with a human lung-on-a-chip. The lungs-on-a-chip were formed from the cells of healthy participants and those with Chronic Obstructive Pulmonary Disease (COPD), a chronic inflammatory lung disease that labors breathing and the third leading cause of death in humans, to discover how smoking affects these patients differently.
The combination of the smoking robot and the lung-on-a-chip facilitates a realistic environment with a controlled participant that was previously unattainable. Human subjects aren’t consistent enough to procure dependable results while most animals commonly used in research only breathe through their nose, making it difficult to be exposed to realistic smoke. Another reason researchers chose to look into the lung-on-a-chip method is due to animals in studies, more often than not, are not predictors of what will happen in humans. This approach allows the study of smoking’s effects without harming subjects in the process.
To create their model, the team first constructed a micro-respirator to mimic a ribcage and diaphragm in order to inhale and exhale air. Next was the lung-on-a-chip, which is able to replicate the complex physiology of living human organs. The third component was a machine to light and hold the cigarettes before funneling the smoke into the chamber where the lung-on-a-chip resides. Lastly is the software that controls the breathing profile. Researchers timed the inhalations to be similar to that of real smokers.
After looking at the patterns of gene expression in the lung cells exposed to cigarette smoke, the researchers found 335 significant modifications caused by smoking. Their results are similar to other research studying gene expression in smokers, establishing that their experiment model is an imitation of the human lungs of a smoker.
Researchers observed, after only 9 cigarettes, that COPD patients showed a larger inflammatory response to the smoke in comparison to healthy patients. Their cilia, the hair-like structures that line the lungs and transport bacteria carrying mucus out of the bronchi, were disrupted. They appeared disoriented and could not perform their function as they normally would.
Donald Ingber, one of the robot’s creators and director of the Wyss Institute, has said this is, “probably why people who smoke are coughing and have more mucus.”
A genetic analysis of the lung chips grown from COPD cells found a set of ten entirely new affected genes. The genes of COPD patients seem to be most heavily affected comparatively and show that smoking can affect those with the disease differently.
After testing traditional cigarettes, the research team made a switch to e-cigarettes. This research, based on the same model, found that the patterns of gene expression exhibiting weakened cilia was absent with e-cigs and could possibly be safer than traditional cigarettes.
