ASSESSMENT OF ENDOTHELIAL NITRIC OXIDE SYNTHASE LEVELS IN CHILDREN WITH COVID-19 OF VARYING SEVERITY AND MULTISYSTEM INFLAMMATORY SYNDROME IN CHILDREN, AND ITS DIAGNOSTIC SIGNIFICANCE
DOI:
https://doi.org/10.11603/mcch.2410-681X.2026.i2.16070Abstract
Introduction. Endothelial nitric oxide synthase (eNOS) plays an important role in the regulation of vascular tone, microcirculation, and antiviral defense. Impaired eNOS function may represent one of the mechanisms underlying endothelial dysfunction, hypoxia, and a more severe course of SARS-CoV-2 infection in children. The aim of the study − to determine the diagnostic significance of endothelial nitric oxide synthase levels in the course of SARS-CoV-2 infection in children. Research Methods. The study included 200 children diagnosed with coronavirus disease 2019 (COVID-19), 40 children with multisystem inflammatory syndrome in children (MIS-C), and 45 children in the control group who were not infected with SARS-CoV-2. The age of the examined children ranged from 1 month to 17 years. The level of eNOS, encoded by the NOS3 gene, was determined using an enzyme-linked immunosorbent assay (ELISA) with the Elabscience Human NOS3/eNOS (Nitric Oxide Synthase 3, Endothelial) ELISA Kit (E-EL-H0755). Statistical analysis was performed using GraphPad Prism 8.4.3 and Statistica 13.0 (StatSoft Inc., Tulsa, Oklahoma, USA). Results and Discussion. Children with moderate and severe COVID-19, as well as those with MIS-C, had significantly lower eNOS levels compared with healthy children not infected with SARS-CoV-2. Among boys with COVID-19, eNOS levels were significantly lower than in boys with MIS-C (p<0.05), whereas no statistically significant differences between the COVID-19 and MIS-C groups were observed among girls (p>0.05). An eNOS level below 453.00 pg/mL was found to have diagnostic significance for identifying severe COVID-19 in children aged 1 month to 17 years. At the same time, an eNOS level below 427.30 pg/mL was associated with an increased likelihood of MIS-C, with a positive likelihood ratio of 2.74. Conclusions. eNOS may be considered a potential biomarker of a more severe course of SARS-CoV-2 infection in children, as its decrease is associated with severe COVID-19 and the development of MIS-C.
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