In an add-on study of the WHO Solidarity trial, Norwegian investigators examined the effect of remdesivir and hydroxychloroquine on the degree of clinical respiratory failure, on SARS-CoV-2 viral load in the oropharynx, and on levels of inflammatory variables in plasma or serum.
Background
Although coronavirus disease 2019 (COVID‐19) is primarily a respiratory infection, mounting evidence suggests that the gastrointestinal tract is involved in the disease, with gut barrier dysfunction and gut microbiota alterations being related to disease severity. Whether these alterations persist and are related to long‐term respiratory dysfunction remains unknown.
Methods
Plasma was collected during hospital admission and after 3 months from the NOR‐Solidarity trial (n = 181) and analyzed for markers of gut barrier dysfunction and inflammation. At the 3‐month follow‐up, pulmonary function was assessed by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO). Rectal swabs for gut microbiota analyses were collected (n = 97) and analyzed by sequencing the 16S rRNA gene.
Results
Gut microbiota diversity was reduced in COVID‐19 patients with respiratory dysfunction, defined as DLCO below the lower limit of normal 3 months after hospitalization. These patients also had an altered global gut microbiota composition, with reduced relative abundance of 20 bacterial taxa and increased abundance of five taxa, including Veillonella, potentially linked to fibrosis. During hospitalization, increased plasma levels of lipopolysaccharide‐binding protein (LBP) were strongly associated with respiratory failure, defined as pO2/fiO2 (P/F ratio) <26.6 kPa. LBP levels remained elevated during and after hospitalization and were associated with low‐grade inflammation and respiratory dysfunction after 3 months.
Conclusion
Respiratory dysfunction after COVID‐19 is associated with altered gut microbiota and persistently elevated LBP levels. Our results should be regarded as hypothesis generating, pointing to a potential gut–lung axis that should be further investigated in relation to long‐term pulmonary dysfunction and long COVID.
Despite numerous studies on SARS-CoV-2induced inflammation, we still lack markers for rapid disease progression with admission to intensive care unit (ICU) or respiratory failure (RF). Few studies have evaluated the prognostic value of routine diagnostic repertoire available at most hospitals. The NOR-Solidarity trial is an independent add-on study to the WHO Solidarity trial, evaluating hydroxychloroquine (HCQ) and remdesivir compared to standard of care in hospitalized COVID-19 patients [1]. We explored whether standard biomarkers in peripheral blood could give information on ICU admission and RF in hospitalized COVID-19 patients.Adult patients admitted to 23 Norwegian hospitals with PCR-confirmed SARS-2-CoV-2 infection were eligible for participation. In this substudy, the routine biochemistry was related to (i) the need for ICU admission or (ii) RF defined as pO 2 /FiO 2 (P/F ratio) < 26.6 kPa during the first 10 days of hospitalization. Routine peripheral blood samples were collected at inclusion and daily until discharge from the hospital, and outpatients were followed up 3 months after discharge. Markers included were C-reactive protein (CRP), ferritin, lactate dehydrogenase (LDH), haemoglobin, fibrinogen, procalcitonin (PCT), D-dimer, platelet count, total white blood cell count, monocyte, neutrophil and lymphocyte count. Exclusion criteria, intervention, ethical statement, details on viral load and SARS-CoV-2 antibodies and statistical analysis are given in the Supporting Information file.
Objective: Although COVID-19 is primarily a respiratory infection, mounting evidence suggests that the GI tract is involved in the disease, with gut barrier dysfunction and gut microbiota alterations being related to disease severity. Whether these alterations persist and could be related to long-term respiratory dysfunction is unknown.
Design: From the NOR-Solidarity trial (n=181), plasma was collected during hospital admission and after three months, and analyzed for markers of gut barrier dysfunction and inflammation. At the three-month follow-up, pulmonary function was assessed by measuring diffusing capacity of the lungs for carbon monoxide (DLCO), and rectal swabs for gut microbiota analyses were collected (n= 97) and analysed by sequencing of the 16S rRNA gene.
Results: Gut microbiota diversity was reduced in COVID-19 patients with persistent respiratory dysfunction, defined as DLCO below lower limit of normal three months after hospitalization. These patients also had an altered global gut microbiota composition, with reduced abundance of Erysipelotrichaceae UCG-003 and increased abundance of Flavonifractor and Veillonella, the latter potentially being linked to fibrosis. During hospitalization, increased plasma levels of lipopolysaccharide-binding protein (LBP) were strongly associated with respiratory failure, defined as pO2/fiO2-(P/F-ratio)<26.6 kPa. LBP levels remained elevated during and after hospitalization, and was associated with low-grade inflammation and persistent respiratory dysfunction after three months.
Conclusion: Persistent respiratory dysfunction after COVID-19 is associated with reduced biodiversity and gut microbiota alterations, along with persistently elevated LBP levels. Our results point to a potential gut-lung axis that should be further investigated in relation to long-term pulmonary dysfunction and long COVID.
Jaundice due to bile duct obstruction by opisthorchiasis/clonorchiasis is a well-known problem in South-East Asia. It may become more common in Europe as well as a result of increasing migration. Treatment with Praziquantel is simple and effective.
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