Soluble urokinase plasminogen activator receptor (suPAR) as a prognostic marker in COVID-19 patients: a systematic review

OBJECTIVE

The aim of this study was to perform a systematic review of the usefulness of suPAR as a prognostic marker in non-critical COVID-19 patients.

MATERIALS AND METHODS

We carried out a literature search in MEDLINE, Embase, and Web of Science using the following keywords: ("soluble urokinase receptor" OR "urokinase plasminogen activator receptor" OR "suPAR" OR "soluble uPAR" OR "soluble uPA receptor") AND ("COVID-19" OR "SARS-CoV-2"). We included observational studies (descriptive or analytic) that measured plasma suPAR on COVID-19 patients 18 years old or older, with non-critical disease at the beginning of the study.

RESULTS

After screening and eligibility assessment, a total of 16 articles were included in the review. Most studies that measured mean differences found that suPAR levels were higher in patients with worse outcomes. The studies that measured diagnostic accuracy concluded that suPAR was highly sensitive and moderately specific to predicting bad outcomes. Studies that performed a survival analysis found that patients with high suPAR levels were more at risk of bad outcomes. Most of the studies included in this review were performed before extensive vaccination and omicron wave.

CONCLUSIONS

COVID-19 patients with moderate initial disease and elevated suPAR levels are more at risk of poor outcomes. Larger prospective clinical trials are needed to confirm the results obtained in this review.

Description of two cultivated and two uncultivated new Salinibacter species, one named following the rules of the bacteriological code: Salinibacter grassmerensis sp. nov.; and three named following the rules of the SeqCode: Salinibacter pepae sp. nov., Salinibacter abyssi sp. nov., and Salinibacter pampae sp. nov

Current -omics methods allow the collection of a large amount of information that helps in describing the microbial diversity in nature. Here, and as a result of a culturomic approach that rendered the collection of thousands of isolates from 5 different hypersaline sites (in Spain, USA and New Zealand), we obtained 21 strains that represent two new Salinibacter species. For these species we propose the names Salinibacter pepae sp. nov. and Salinibacter grassmerensis sp. nov. (showing average nucleotide identity (ANI) values < 95.09% and 87.08% with Sal. ruber M31^T, respectively). Metabolomics revealed species-specific discriminative profiles. Sal. ruber strains were distinguished by a higher percentage of polyunsaturated fatty acids and specific N-functionalized fatty acids; and Sal. altiplanensis was distinguished by an increased number of glycosylated molecules. Based on sequence characteristics and inferred phenotype of metagenome-assembled genomes (MAGs), we describe two new members of the genus Salinibacter. These species dominated in different sites and always coexisted with Sal. ruber and Sal. pepae. Based on the MAGs from three Argentinian lakes in the Pampa region of Argentina and the MAG of the Romanian lake Fără Fund, we describe the species Salinibacter pampae sp. nov. and Salinibacter abyssi sp. nov. respectively (showing ANI values 90.94% and 91.48% with Sal. ruber M31^T, respectively). Sal. grassmerensis sp. nov. name was formed according to the rules of the International Code for Nomenclature of Prokaryotes (ICNP), and Sal. pepae, Sal. pampae sp. nov. and Sal. abyssi sp. nov. are proposed following the rules of the newly published Code of Nomenclature of Prokaryotes Described from Sequence Data (SeqCode). This work constitutes an example on how classification under ICNP and SeqCode can coexist, and how the official naming a cultivated organism for which the deposit in public repositories is difficult finds an intermediate solution.