US researchers have identified an unknown cell type present in the lungs of people who smoke. These cells remain in the body, even when smoking is stopped.
Lungs that darken and take on a necrotic appearance. The effects of tobacco on the lungs have been known for a long time, even in occasional smokers. However, cigarettes could also have an effect directly on the cells. Smokers would even have a type of cell that does not exist in people who do not smoke. This is the discovery made by a scientific team from the Boston University School of Medicine, in the United States. Their results are published in the journal Science Advances.
“The human bronchial epithelium (the layer of cells that covers the wall of the bronchi) is composed of several distinct cell types that cooperate to defend themselves against attacks from the external environment. The bronchi are lined with an epithelium which acts as a physical barrier against exposure to aggressions such as inhaled toxins, allergens and pathogens”, explain the authors of the study. This cooperative process between cells to eliminate inhalants also works when inhaling tobacco smoke.
To conduct their study, the researchers compared the bronchial epithelium of six smokers to that of six non-smokers. Each participant underwent a bronchoscopy, a test that involves examining a patient’s airways, trachea and large bronchi while they are asleep. In addition, the scientific team collected cells from their airways, which were then analyzed.
Detect Abnormalities in the Lungs Earlier
Several differences were highlighted. First, some cell types had decreased significantly between non-smokers and smokers, others had increased. But above all, the researchers discovered a subpopulation of cells that had never been identified before. Their origin and role are currently unknown. But “these irreversible alterations in the composition of the bronchial epithelium could be the cause of chronic diseases”, think the authors.
The sequencing of these cells also showed the presence of the CEACAM5 gene, also found in pre-cancerous lung tissue as well as in lung tumours. This new “cellular landscape” could make the lungs weaker in the face of disease. Worse still, the cell no longer disappears from the body once it is present, according to the study.
For researchers, better understanding the consequences of tobacco on cells will help to understand the transition from a healthy state to a diseased state. “We hope that this study and the work that will result from it will lead to effective strategies for the early detection, prevention and control of tobacco-associated lung diseases,” adds Joshua Campbell, assistant professor of medicine at Boston University. and author of the study. In France, around 46,000 cases of lung cancer were diagnosed in 2018, according to the Institut Curie.
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