Further metabolite-based analysis may help identify the mechanisms underlying pulmonary dysfunction in COVID-19 survivors and provide potential therapeutic targets in the future, according to the results of a random, outcome-stratified, case-control study published in Clinical Infectious Diseases.

Clarification of the molecular mechanisms involved in the pathogenesis of COVID-19 may help to discover therapeutic targets; therefore, researchers compared the metabolomic profiles of circulating plasma from 103 patients who had recovered from COVID-19 with pulmonary sequelae 3 months after discharge to 27 healthy donors. The researchers performed pulmonary function tests, computerized tomography (CT) scans, laboratory examinations, and liquid chromatography-mass spectrometry.

The plasma metabolite profiles of COVID-19 survivors with abnormal pulmonary function were “evidently different” from those of healthy donors or individuals with normal pulmonary function. These alterations were associated with disease severity, and mainly involved amino acid and glycerophospholipid metabolic pathways. Furthermore, increased levels of triacylglycerols, phosphatidylcholines, prostaglandin E2, arginine, and decreased levels of betain and adenosine were associated with pulmonary CO diffusing capacity and total lung capacity. The global plasma metabolomic profiles were different between individuals with abnormal and normal pulmonary function.


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This study had several limitations in that it was a single-center, prospective study with a relatively small sample size. In addition, patients with asymptomatic infection were not included in this study. Blood routine tests, liver and kidney function tests, and chest CT findings were also not sensitive indicators of the organ injury presented by metabolomics. The researchers noted that larger-sized studies with more sensitive measures are warranted.

“Pathway analysis revealed that these alterations related to abnormal pulmonary function mainly involved the metabolic pathways of lysine degradation, taurine and hypotaurine metabolism, alpha-linolenic acid metabolism, glycerophospholipid metabolism, arginine biosynthesis, as well as arginine and proline metabolism,” the study authors wrote.

Reference

Xu J, Zhou M, Luo P, et al. Plasma metabolomic profiling of patients recovered from COVID-19 with pulmonary sequelae 3 months after discharge. Clin Infect Dis. Published online February 17, 2021. doi:10.1093/cid/ciab147