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. 2021 Dec 20;10(12):2022.
doi: 10.3390/antiox10122022.

Mild Coronavirus Disease 2019 (COVID-19) Is Marked by Systemic Oxidative Stress: A Pilot Study

Larissa E van Eijk  1 , Adriana Tami  2 , Jan-Luuk Hillebrands  1 , Wilfred F A den Dunnen  1 , Martin H de Borst  3 , Peter H J van der Voort  4 , Marian L C Bulthuis  1 , Alida C M Veloo  2 , Karin I Wold  2 , María F Vincenti González  2 , Bernardina T F van der Gun  2 , Harry van Goor  1 , Arno R Bourgonje  5
Affiliations

Mild Coronavirus Disease 2019 (COVID-19) Is Marked by Systemic Oxidative Stress: A Pilot Study

Larissa E van Eijk et al. Antioxidants (Basel). .

Abstract

Oxidative stress has been implicated to play a critical role in the pathophysiology of coronavirus disease 2019 (COVID-19) and may therefore be considered as a relevant therapeutic target. Serum free thiols (R-SH, sulfhydryl groups) comprise a robust marker of systemic oxidative stress, since they are readily oxidized by reactive oxygen species (ROS). In this study, serum free thiol concentrations were measured in hospitalized and non-hospitalized patients with COVID-19 and healthy controls and their associations with relevant clinical parameters were examined. Serum free thiol concentrations were measured colorimetrically (Ellman's method) in 29 non-hospitalized COVID-19 subjects and 30 age-, sex-, and body-mass index (BMI)-matched healthy controls and analyzed for associations with clinical and biochemical disease parameters. Additional free thiol measurements were performed on seven serum samples from COVID-19 subjects who required hospitalization to examine their correlation with disease severity. Non-hospitalized subjects with COVID-19 had significantly lower concentrations of serum free thiols compared to healthy controls (p = 0.014), indicating oxidative stress. Serum free thiols were positively associated with albumin (St. β = 0.710, p < 0.001) and inversely associated with CRP (St. β = -0.434, p = 0.027), and showed significant discriminative ability to differentiate subjects with COVID-19 from healthy controls (AUC = 0.69, p = 0.011), which was slightly higher than the discriminative performance of CRP concentrations regarding COVID-19 diagnosis (AUC = 0.66, p = 0.042). This study concludes that systemic oxidative stress is increased in patients with COVID-19 compared with healthy controls. This opens an avenue of treatment options since free thiols are amenable to therapeutic modulation.

Keywords: COVID-19; free thiols; oxidative stress; redox.

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Conflict of interest statement

All authors have no conflict of interest to declare.

Figures

Figure 1
Figure 1
(A) Kernel density estimation of the distributions of serum free thiol concentrations among subjects with mild COVID-19 and healthy controls, demonstrating a normal distribution in both groups. Density estimates were performed using a Gaussian kernel. (B) Baseline serum concentrations of free thiols (µM) are significantly reduced in subjects with mild COVID-19 as compared to healthy controls (* p = 0.014).
Figure 2
Figure 2
(A) Serum CRP concentrations are inversely associated with serum free thiol concentrations (R-SH) (St. β = −0.434, p = 0.027) in mild COVID-19 subjects. (B) Serum albumin is positively associated with serum free thiol concentrations (R-SH) (μM) (St. β = 0.710, p < 0.001) in mild COVID-19 subjects.
Figure 3
Figure 3
(A) Serum concentrations of free thiols (µM) significantly discriminated between patients with COVID-19 and healthy controls and (B) showing a slightly higher discriminative capacity as compared to CRP concentrations (mg/L).
See this image and copyright information in PMC

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