Acute pneumonia is mostly caused by infectious pathogens (e.g., bacteria, viruses, and fungi), leading to an inflammatory condition of the lungs. Acute pneumonia has been one of the major causes of death in the past several years. In addition to acute pneumonia-related respiratory failure, neurological disorders after severe acute pneumonia are common complications that reduce patient’s quality of life. A very recent example is “brain fog” occurring in “long coronavirus disease (long-COVID)” . Neurological syndromes after severe pneumonia exist in recovered patients with many respiratory diseases. One study showed that the frequencies of most neurological manifestations did not differ after coronavirus disease 2019 (COVID-19), influenza, and bacterial pneumonia, indicating a potential general mechanism involved in all acute pneumonia–induced neurological disorders. Given the major role of astrocytes and microglia in neuroinflammation, there is growing evidence suggesting that a detrimental immune response in the brain contributes to neurological symptoms after severe pneumonia. Yet, it still remains controversial whether the alteration of the brain is induced by direct inflammatory responses from the lung or the bystander effects of pneumonia. The relationship between acute pneumonia and brain activity has not been elucidated.
Recently, the group of Prof. Chao Wang of our Institute shows that the neurological syndromes after severe acute pneumonia are partly attributed to the translocation of endogenous bacteria from the lung to the brain during pneumonia. Using principal components analysis, similarities were found between the brain’s flora species and those of the lungs, indicating that the bacteria detected in the brain may originate from the lungs. The researchers also observed impairment of both the lung-blood and brain-blood barriers, allowing endogenous lung bacteria to invade the brain during pneumonia. Collectively, The researchers identify endogenous lung bacteria that play a role in altering brain homeostasis, which provides insight into the mechanism of neurological syndromes after severe pneumonia. The relevant results were published online October 19, 2023 in Science Advances. Dr. Qingle Ma is the first author of this paper.
Link: https://www.science.org/doi/10.1126/sciadv.adi0699
Title: Neurological Disorders after Severe Pneumonia are Associated with Translocation of Endogenous Bacteria from Lung to Brain
Authors: Qingle Ma, Chenlu Yao, Yi Wu, Heng Wang, Qin Fan, Qianyu Yang, Jialu Xu, Huaxing Dai, Yue Zhang, Fang Xu, Ting Lu, Jennifer K. Dowling, Chao Wang*.
Group page: http://funsom.suda.edu.cn/c3/9d/c2735a50077/page.htm
Editor: Guo Jia