14 DAY TRIAL // You would think that doctors and scientists know all there is to know about the human body but the new discovery of taste receptors within the lungs came to contradict this idea.
Researchers at the University of Maryland School of Medicine in Baltimore have made an amazing discovery – by accident: they found out that bitter taste receptors are not located only in the mouth, but also in human lungs.
After analyzing these taste receptors, the researchers think that this could boost up the treatment of asthma and other obstructive lung diseases.
At first, even the researchers were skeptical about the discovery, said the study's senior author, Stephen B. Liggett, MD, professor of medicine and physiology at the University of Maryland School of Medicine and director of its Cardiopulmonary Genomics Program.
They actually found the taste receptors by accident, while carrying out a study on human lung muscle receptors that control airway contraction and relaxation.
The taste receptors in the lungs are not clustered in buds, nor they send messages to the brain, nevertheless they react to bitter-tasting substances.
Dr Liggett's team thought that most plant-based poisons are bitter, so the purpose of these lung bitter-taste receptors was to warn against poisons.
The team tested the receptors by exposing non-toxic, plant-based, bitter-tasting compounds to human and mouse airways, individual airway smooth muscle cells, and asthmatic mice.
Except that the results were far from what the team expected to find: the bitter compounds “opened the airway more profoundly than any known drug that we have for treatment of asthma or chronic obstructive pulmonary disease (COPD),” said Dr Liggett.
This amazing discovery could have a tremendous importance for the development of new therapies, and “new drugs to treat asthma, emphysema or chronic bronchitis are needed.
“This could replace or enhance what is now in use, and represents a completely new approach.”
The researchers also tested quinine and chloroquine (used for treating malaria), and even saccharin, with its bitter aftertaste, and the compounds opened the contracted airways.
Another discovery the team made while testing different bitter compounds was that in an aerosolized form, the bitter substances relaxed the airways in asthmatic mice, which can only be a step forward in treating this disease.
Still, Dr. Liggett added that eating bitter food will have no effect whatsoever in treating asthma: “based on our research, we think that the best drugs would be chemical modifications of bitter compounds, which would be aerosolized and then inhaled into the lungs with an inhaler,” he said.
E. Albert Reece, MD, PhD, M.B.A., vice president for medical affairs at the University of Maryland and dean of the University of Maryland School of Medicine said: “the work of this team exemplifies what it takes to make real improvements in treating certain diseases.
“These researchers were willing to take chances and ask questions about an unlikely concept.
“Why are taste receptors in the lungs?
“What do they do?
“Can we take advantage of them to devise a new therapy? In the end, their discoveries are in the best tradition of scientific research.”
Asthma and COPD together affect 300 million people worldwide, out of which 23 million are Americans, according to the American Lung Association.
This research was supported by grants from the National Heart, Lung, and Blood Institute of the National Institutes of Health, and the results are published online in Nature Medicine.