ABSTRACT
Chronic alcohol abuse increases the risk of mortality and poor outcomes in patients with acute respiratory distress syndrome. However, the underlying mechanisms remain to be elucidated. The present study aimed to investigate the effects of chronic alcohol consumption on lung injury and clarify the signaling pathways involved in the inhibition of alveolar fluid clearance (AFC). In order to produce rodent models with chronic alcohol consumption, wildtype C57BL/6 mice were treated with alcohol. A2a adenosine receptor (AR) small interfering (si)RNA or A2bAR siRNA were transfected into the lung tissue of mice and primary rat alveolar type II (ATII) cells. The rate of AFC in lung tissue was measured during exposure to lipopolysaccharide (LPS). Epithelial sodium channel (ENaC) expression was determined to investigate the mechanisms underlying alcoholinduced regulation of AFC. In the present study, exposure to alcohol reduced AFC, exacerbated pulmonary edema and worsened LPSinduced lung injury. Alcohol caused a decrease in cyclic adenosine monophosphate (cAMP) levels and inhibited αENaC, ßENaC and γENaC expression levels in the lung tissue of mice and ATII cells. Furthermore, alcohol decreased αENaC, ßENaC and γENaC expression levels via the A2aAR or A2bARcAMP signaling pathways in vitro. In conclusion, the results of the present study demonstrated that chronic alcohol consumption worsened lung injury by aggravating pulmonary edema and impairing AFC. An alcoholinduced decrease of αENaC, ßENaC and γENaC expression levels by the A2ARmediated cAMP pathway may be responsible for the exacerbated effects of chronic alcohol consumption in lung injury.
Subject(s)
Acute Lung Injury/metabolism , Alveolar Epithelial Cells/metabolism , Epithelial Sodium Channels/drug effects , Epithelial Sodium Channels/metabolism , Ethanol/pharmacology , Receptors, Adenosine A2/metabolism , Acute Lung Injury/chemically induced , Acute Lung Injury/pathology , Alveolar Epithelial Cells/pathology , Animals , Cyclic AMP/metabolism , Cytokines , Lipopolysaccharides/adverse effects , Lung/metabolism , Lung Injury/chemically induced , Lung Injury/metabolism , Lung Injury/pathology , Mice , Mice, Inbred C57BL , Pulmonary Alveoli/metabolism , Pulmonary Edema/chemically induced , Pulmonary Edema/metabolism , Pulmonary Edema/pathology , RNA Splicing Factors/genetics , RNA Splicing Factors/metabolism , Rats , Receptor, Adenosine A2A/genetics , Receptor, Adenosine A2A/metabolism , Signal TransductionABSTRACT
BACKGROUND: Since December 2019, over 80,000 patients with coronavirus disease 2019 (COVID-19) have been confirmed in China. With the increasing number of recovered patients, more attention should be paid to the follow-up of these patients. METHODS: In the study, 576 patients with COVID-19 discharged from hospital in Chongqing, China from January 24, 2020, to March 10, 2020 were evaluated by viral nucleic acid tests for severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) to determine if they could be released from quarantine. Among the 576 patients, 61 patients (10.6%) had positive RT-PCR test results of SARS-CoV-2. We aimed to analyze the demographics, clinical characteristics and treatment of 61 patients. RESULTS: These positive patients were characterized by older age, chronic medical illness and mild conditions. 38 (62.3%) patients who were asymptomatic without abnormalities on chest radiographs were found in the positive with COVID-19. Also, they showed positive results of stool or sputum specimens with negative results of nasal and pharyngeal swab specimens. The median duration of positive result of SARS-CoV-2 was varied from 3 days to 35 days in the patients discharged from hospital with no family member infection. CONCLUSIONS: Multi-site screening of SARS-CoV-2 including nasal and pharyngeal swabs, stool and sputum specimens could be considered to improve the diagnosis, treatment and infection control in patients with COVID-19. Our findings provide the important information and clinical evidence for the improved management of patients recovered from COVID-19.