December 26, 2024
Keio University School of Medicine
Tokyo University of Agriculture and Technology
Chronic obstructive pulmonary disease (COPD) is a major respiratory illness, ranking as the third leading cause of death worldwide. This disease is primarily caused by chronic inflammation of the lungs due to smoking and presents with the characteristic pathological finding of pulmonary emphysema. In recent years, the connection between the gut and lung diseases, mediated by the gut microbiota, has been reported, particularly the role of short-chain fatty acids produced by gut bacteria. However, it was not clear whether the gut microbiota and the short-chain fatty acids they produce are actually involved in the pathophysiology of COPD.
A research group led by Shiro Otake, a graduate student; Shotaro Chubachi, a senior lecturer; and Koichi Fukunaga, a professor at the Division of Pulmonary Medicine, Department of Internal Medicine, Keio University School of Medicine, along with Junki Miyamoto, an associate professor at Tokyo University of Agriculture and Technology, used blood samples from smokers and non-smokers to reveal that smokers have reduced concentrations of short-chain fatty acids in their blood, and that these concentrations correlate with lung function. Subsequently, through experiments using a COPD mouse model, they demonstrated that exposure to smoke alters the gut microbiota and reduces the short-chain fatty acids produced by gut bacteria. In addition, they found that supplementing the diet of the COPD mouse model with dietary fiber increased the body's short-chain fatty acids and suppressed airway inflammation and pulmonary emphysema. Conversely, they showed that administering antibiotics to eliminate gut bacteria markedly decreased short-chain fatty acids, exacerbating airway inflammation and pulmonary emphysema. These findings revealed that gut bacteria are closely involved in the pathophysiology of COPD through the production of short-chain fatty acids. The results of this study suggest that appropriate dietary fiber supplementation could lead to new therapeutic strategies for COPD.
The results of this research were published in Mucosal Immunology on December 13, 2024.
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