Abstract. The pandemic of COVID-19 effected the world not only by itself but left us with long term consequences in a form post-COVID syndrome. The research on oxidative stress markers can provide an understanding on the pathogenesis of COVID-19 and the post COVID syndrome.

Purpose –The aim of this research was determining the content of products of oxidative modification of proteins, lipid peroxidation, levels median molecules and of L-arginine in blood serum in patients with post-COVID syndrome to improve diagnostic and to gain better understanding of long-term biochemical processes that can impact patients’ health.

Materials and Methods. The aim of this research was determining the content of products of oxidative modification of proteins, lipid peroxidation, levels median molecules and of L-arginine in blood serum in patients with post-COVID syndrome to improve diagnostic methods and to gain better understanding of long-term biochemical processes that can impact patients’ health. The content of the products of oxidative modification of proteins was determined by the level of carbonyl derivatives, which are detected by the reaction with 2,4-dinitrophenylhydrazine. The indicators of lipid peroxidation (LPO) were determined by the spectrophotometric method proposed by R. A. Timirbulatov and E. I. Seleznyov. Oxidative modification of proteins (OMP) in serum was determined by the spectrophotometric method modified by E. E. Dubinina. To determine L-arginine in venous blood serum, K. N. Veremienko, O. P. Holoborodko, and A. I. Kizym proposed a reaction with α-naphthol. The concentration of middle molecules (MM) in blood was determined by a screening method proposed by N. I. Gabrielian and V. I. Lipatova. The Mann-Whitney U non-parametric statistical test was employed for statistical calculations.

Results. The study investigated 82 patients diagnosed with COVID-19 (mean age 44.2 years) to evaluate biochemical markers associated with postCOVID syndrome. Among the participants, 61 (74.0 %) experienced symptoms lasting over 12 weeks. Significant differences were found in neutral aldehyde and ketone levels at E max wavelengths of 356 nm and 370 nm, comparing the control group (Group A) with patients without post COVID syndrome (Group B) and who developed post-COVID syndrome (Group C) at both time points (p < 0.0001). Additionally, post-COVID patients exhibited higher levels of basic aldehydes at E max = 430 nm. The analysis of lipid peroxidation levels revealed differences even between non-post-COVID patients and controls (p < 0.0001). Notably, L-arginine levels also differed significantly between groups, suggesting altered biochemical pathways in those affected. These findings underscore the relevance of monitoring oxidative stress markers to better understand the long-term effects of COVID-19.

Conclusions. The analysis consistently shows significant differences in lipid peroxidation levels, L-arginine concentrations, and middle molecules (MM) between the control group (A), non-post-COVID patients (B), and patients with post-COVID syndrome (C).

Keywords: сovid-19, coronavirus disease, post-covid syndrome, oxidative modification of proteins, lipid peroxidation, median molecules, L-arginine, oxidative stress

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1. Adebayo A, Varzideh F, Wilson S, Gambardella J, Eacobacci M, Jankauskas S.S., Donkor K, Kansakar U, Trimarco V, Mone P, et al. L-Arginine and COVID-19: An Update. Nutrients 2021, 13, 3951. doi.org/10.3390/nu13113951
2. Wu G, Meininger CJ, McNeal CJ, Bazer FW, Rhoads JM. Role of L-Arginine in Nitric Oxide Synthesis and Health in Humans. Adv. Exp. Med. Biol. 2021, 1332, 167-187. doi.org/10.1007/978-3-030-74180-8_10
3. Wang Y, Gorenstein C. Chapter 16 - The Beck Depression Inventory: Uses and applica- tions. In: The Neuroscience of Depression: Features, Diagnosis, and Treatment.
4. Martín-Fernández M, Aller R, Heredia-Rodríguez M, Gómez-Sánchez E, Martínez-Paz P, Gonzalo-Benito H, Sánchez-de Prada L, Gorgojo Ó, Carnicero-Frutos I, Tamayo E, & Tamayo-Velasco Á. (2021). Lipid peroxidation as a hallmark of severity in COVID-19 patients. Redox Biology, 48, Article 102181. doi.org/10.1016/j.redox.2021.102181
5. Davis, H. E., et al. (2021). Characterizing long COVID in an international cohort: Seven months of symptoms and their impact. EclinicalMedicine, 38, 101019. doi.org/10.1016/j.eclinm.2021.101019
6. Li, J., Zhou, Y., Ma, J., et al. (2023). The long-term health outcomes, pathophysiological mechanisms, and multidisciplinary management of long COVID. Signal Transduction and Targeted Therapy, 8, 416.doi.org/10.1038/s41392-023-01640-z