Introduction. Influenza and other acute respiratory viral infections (ARVI) account for a significant share in the structure of childhood infectious diseases. The determination of medium-weight molecules (MMM) and the calculation of leukocyte intoxication indices in respiratory pathology in children are of interest for studying and searching for informative markers. The aim of the work: to determine the diagnostic significance of indices characterizing the state of endogenous intoxication in children with seasonal influenza and ARVI. Materials and methods. One hundred twenty five patients were examined, of which 76 children diagnosed with influenza made up the main group (42 boys, 34 girls, average age of 5.2 ± 2.3 g), the comparison group consisted of 49 children diagnosed with acute respiratory viral infections (27 boys, 22 girls, average age 5.6 ± 2.5 yr). The control group consisted of 112 conditionally healthy children, groups of children being comparable in gender and age. The levels of MMM were determined by spectrophotometry. Statistical data analysis was performed with the Statistica 6.0 software. Results. In patients with influenza, multiple correlations there were found between MMM and island-inflammatory proteins. The distribution coefficient in patients with influenza and ARVI did not differ significantly, while it significantly correlated in both groups with the rate of erythrocyte sedimentation and the level of C-reactive protein (CRP), (p = 0.000), the aromaticity coefficient and the peptide-nucleotide coefficient significantly correlated with the level of CRP in influenza (p < 0.05). The Garkavi index was higher in 67% of cases of influenza, 53% of cases of ARVI, the allergization index and the leukocyte intoxication index according to V.K. Ostrovsky’s was slightly elevated in children with ARVI. Conclusion. The determination of MMM and the calculation of leukocyte intoxication indices in children with respiratory viral infection provides an objective assessment of the degree of endotoxicosis. The established correlations of the distribution coefficient with the indices of inflammation allow recommending its use in clinical practice.

The literature review is devoted to the problem of exogenous-constitutional obesity and the role of oxidative stress (OS) in this form of obesity. The issues of modern diagnostics and pathogenesis of exogenous-constitutional obesity are considered. The results of various studies devoted to the study of OS in obesity in both laboratory animals and humans are presented. Excess body weight is often accompanied by increased OS and subclinical systemic inflammation. The need to correct the antioxidant status of the body is a topical issue, an important part of which is an individual approach to the selection of agents and dosages in order to reduce the negative impact of free radicals at the cellular level. A significant problem is the lack of a single standard for determining OS parameters, which requires standardized laboratory equipment, in this regard, the choice of a specific method is a responsible step for a research specialist. In this area, there are still many questions that require more detailed study.

We studied the histological structure of the hippocampus in male and female Wistar rats kept on a standard vivarium diet (StD) or a high-calorie diet (HCD) for 16 weeks. The effect of diet-induced visceral obesity correction was also evaluated. To this end, the rats receiving HCD for 8 weeks were transferred to StD for the next 8 weeks. HCD for 16 weeks led to diet-induced visceral obesity and disturbances in the histological structure of the hippocampus in both males and females. The most typical consequences of HCD were neurodegenerative signs, which appeared in different regions of the hippocampus. Transition to StD was effective not only in correcting visceral obesity, but also in leveling neurodegenerative changes in the structure of hippocampal neurons in male and female rats.

BACKGROUND: Balanced nutrition is a key component in the prevention of cardiovascular diseases. An adequate intake of fatty acids in the adolescent diet can contribute to resistance against adverse environmental factors. The activity of lipid peroxidation reactions and the antioxidant defense system serves as an indicator of the body’s resistance to adverse influences and its adaptive capacity. However, rural adolescents remain an understudied population. AIM: To characterize the fatty acid composition of the diets, assess parameters of the lipid peroxidation–antioxidant defense system, and examine potential correlations between them in rural adolescents. METHODS: A cross-sectional analysis was conducted among 76 adolescents (38 boys and 38 girls) aged 14–17 years residing in rural areas of Irkutsk Region. Actual dietary intake was assessed using the 24-hour dietary recall method and compared to established physiological requirements for energy and nutrients. Parameters of the lipid peroxidation–antioxidant defense system were evaluated using spectrophotometric and fluorometric methods. RESULTS: The dietary status of rural adolescents was characterized by elevated intake of saturated and monounsaturated fatty acids and a deficiency in polyunsaturated omega-3 and omega-6 fatty acids. Notably low intake levels were observed for monounsaturated (myristoleic, palmitoleic) and polyunsaturated (alpha-linolenic, arachidonic, docosahexaenoic, and eicosapentaenoic) fatty acids. Blood analyses in adolescents revealed elevated levels of secondary end products of lipid peroxidation, α-tocopherol, and reduced glutathione, along with decreased levels of primary products, total antioxidant activity, and retinol. Correlation analysis revealed associations between ketodienes and conjugated trienes and estimated dietary level of oleic acid; TBA-reactive substances and arachidonic acid; total antioxidant activity and caprylic and lauric acids; superoxide dismutase activity and estimated dietary level of docosahexaenoic; α-tocopherol and behenic acid. Multiple positive correlations were found between oxidized glutathione and estimated dietary level of caprylic, lauric, palmitic, and stearic acids, total monounsaturated fatty acids, palmitoleic acid, and oleic acid. CONCLUSION: Estimated intake levels of saturated and unsaturated fatty acids help identify dietary deficiencies in rural adolescents and may be associated with high systemic lipid peroxidation activity.

BACKGROUND: Polycystic ovary syndrome is considered a pressing problem that significantly reduces the quality of life of women. Patients with androgenic phenotypes of this disease are allocated to a special observation group for the development of metabolic disorders and related complications. It has now been proven that there are ethnic differences in the manifestations of polycystic ovary syndrome, but its hormonal and metabolic aspects in representatives of the indigenous ethnic groups of Eastern Siberia have not yet been assessed. Understanding these processes will contribute to the personalization of the prevention and treatment of polycystic ovary syndrome in reproductive age. AIM: The aim of this study was to determine changes in the parameters of neuroendocrine regulation and oxidative stress in reproductive-age women of different ethnic groups with hyperandrogenic phenotypes of polycystic ovary syndrome. METHODS: This study included 186 women of reproductive age (18–44 years old) living in the Irkutsk region and the Republic of Buryatia. Groups of women with polycystic ovary syndrome of Russian (n = 67) and Buryat (n = 27) ethnic groups and corresponding control groups (n = 68 and n = 24) were formed. RESULTS: Both Russian and Buryat ethnic patients with polycystic ovary syndrome had elevated testosterone levels, free androgen indices, and dehydroepiandrosterone sulfate levels, as well as reduced sex hormone-binding globulin levels relative to the corresponding control values. At the same time, Russian patients also had increased anti-Müllerian hormone levels. Oxidative stress parameters in the group of Russian ethnic women with polycystic ovary syndrome were expressed by elevated retinol levels, while in Buryat ethnic women, they were expressed by increased values of thiobarbituric acid products, as well as reduced glutathione and α-tocopherol levels. CONCLUSION: The data obtained indicate the presence of dramatic changes in neuroendocrine regulation in women with polycystic ovary syndrome, regardless of ethnicity. At the same time, compensatory shifts in the antioxidant defense system in women of the Russian ethnicity and activation of lipid peroxidation in patients of the Buryat ethnic group were revealed. The results also indicate the need to assess and control the levels of these metabolites in women with polycystic ovary syndrome, taking into account their ethnicity.

Background: The study aimed to evaluate the parameters of lipid metabolism and lipid peroxidation (LPO) - antioxidant defense (AOD) system disorders in Caucasian women with metabolic syndrome (MetS) and hyperandrogenism (HA). Methods and Results: 300 Caucasian women of reproductive age (18-44 years) living in the Irkutsk region and the Republic of Buryatia territories were examined. According to MetS and polycystic ovary syndrome (PCOS) diagnostic criteria, the following groups were formed: Group 1 included 209 women with MetS, and Group 2 included 23 women with MetS and PCOS (hyperandrogenic phenotypes). The control group (n=68) consisted of practically healthy women. The parameters of lipid metabolism (triglycerides [TG], low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C]), lipid peroxidation system (double bounds [DBs], conjugated dienes [CDs], ketodienes and conjugated trienes [KD and CT], thiobarbituric acids reactive substances [TBARS]), and antioxidant defense (total antioxidant activity [TAA], superoxide dismutase [SOD] activity, reduced glutathione [GSH], oxidized glutathione [GSSG], retinol, alpha-tocopherol) were studied. Spectrophotometric, fluorometric, and statistic methods were used. In Group 1 (MetS), the levels of TG and LDL-C were significantly higher than in the control group (P<0.0001 and P=0.046, respectively). In contrast, the HDL-C level was significantly lower than in the control group (P<0001). Similarly, in Group 2 (MetS+HA), we found an increase in the TG level (P<0.001) and a decrease in the HDL-C level (P=0.008) compared with the control group. (Table 1). There were no differences between Groups 1 and 2 (P>0.05). The LPO reactions were more intense in women with MetS, characterized by a higher content of substrates with DBs (P=0.010) and TBARS (P=0.037) compared with the control group. In Group 2 (MetS+HA), only the TBARS level was statistically significantly higher (P=0.008) than in the control group. In Group 1 (MetS), the SOD activity and the levels of alpha-tocopherol and retinol were significantly higher than in the control group (P=0.005, P=0.017, and P<0.001, respectively) (Table 3). The SOD activity was significantly lower in Group 2 (MetS+HA) than in Group 1 (MetS) (P=0.043). The remaining indicators of antioxidant defense status did not differ significantly between Groups 1 and 2. Conclusion: The data obtained indicated a proatherogenic nature of lipid metabolism, increased LPO reactions, and a compensatory increase in some components of the AOD system in Caucasian women with MetS. In women with the MetS-HA comorbidity, the activity of AOD factors does not increase.

BACKGROUND: The course of menopause may acquire a pathological trajectory, leading to the development of associated disorders and the formation of climacteric syndrome. The predisposition to pathological conditions can be assessed through evaluation of nonspecific lipid peroxidation processes. It is known that these processes can be influenced by various factors, including ethnicity of the subjects, whereas the impact of place of residence remains poorly studied. AIM: This study aimed to assess the parameters of free radical oxidation and antioxidant defense in menopausal women of Russian and Buryat ethnic groups living in urban and rural areas of the Baikal region, in order to determine the impact of territorial factors of this region on the local population. METHODS: The study included 344 women in the climacteric period, divided into four groups: Russian ethnic group, urban (n=115); Russian ethnic group, rural (n=43); Buryat ethnic group, urban (n=129); Buryat ethnic group, rural (n=57). In all women, lipid peroxidation parameters were measured: the levels of substrates with isolated double bonds, diene conjugates, ketodienes and conjugated trienes, and thiobarbituric acid reactive substances. Assessment of antioxidant defense components included determination of superoxide dismutase activity, total antioxidant activity of blood, concentrations of α-tocopherol and retinol, levels of reduced and oxidized glutathione, and calculation of their ratio. Differences were considered significant at p 0.05. RESULTS: Russian women living in rural areas had higher levels of substrates with isolated double bonds (p=0.013), diene conjugates (p=0.018), ketodienes and conjugated trienes (p=0.047), thiobarbituric acid reactive substances (p=0.011), superoxide dismutase activity (p 0.001), and oxidized glutathione (p=0.006), along with lower retinol levels (p=0.001), reduced glutathione (p 0.001), and the reduced/oxidized glutathione ratio (p 0.001), compared to urban residents. Among Buryat women in rural areas, higher levels of substrates with isolated double bonds (p 0.001), diene conjugates (p=0.001), ketodienes and conjugated trienes (p =0.001), thiobarbituric acid reactive substances (p 0.001), superoxide dismutase activity (p = 0.009), α-tocopherol (p=0.043), and oxidized glutathione (p=0.008) were observed compared to urban residents. Ethnic differences were identified only among urban women, with Russian women showing higher values of ketodienes and conjugated trienes (p=0.008), thiobarbituric acid reactive substances (p 0.001), α-tocopherol (p 0.001), retinol (p 0.001), reduced glutathione (p 0.001), and the reduced/oxidized glutathione ratio (p 0.001). CONCLUSION: The ecological characteristics of the Baikal region exert a significant influence on the state of free radical homeostasis in menopausal women of the region’s major ethnic groups.

The investigation of periodontitis pathogenesis is critically important due to its global prevalence. It has been established that periodontitis is associated with chronic periodontal inflammation, alveolar bone loss, the development of oxidative stress, and oral microbiota dysbiosis. Oxidative stress biomarkers (e.g., malondialdehyde, 8-OHdG) and genetic factors (CXCR4, SELL, ITGAL) exacerbate tissue damage and osteoclastogenesis. The oral microbiota plays a significant role in the development and progression of periodontitis through complex interactions with host immune responses, mediated by pathogenic bacteria like Porphyromonas gingivalis and their metabolic byproducts. Emerging therapies targeting OS (e.g., resveratrol, curcumin) and microbial balance highlight the need for integrated treatment strategies. In this context, it is particularly relevant to investigate the interplay between oxidative stress and microbial dysbiosis to develop targeted therapeutic strategies for the prevention and treatment of periodontitis and its systemic complications.

CONTEXT:Previous studies have shown that the prevalence of polycystic ovary syndrome (PCOS) may vary according to race/ethnicity, although a few studies have assessed women of different ethnicities who live in similar geographic and socioeconomic conditions. OBJECTIVE:To determine the prevalence of PCOS in an unselected multiethnic population of premenopausal women. DESIGN:A multicenter prospective cross-sectional study. SETTINGS:The main regional employers of Irkutsk Region and the Buryat Republic, Russia. PARTICIPANTS:During 2016-2019, 1398 premenopausal women underwent a history and physical exam, pelvic ultrasound, and testing during a mandatory annual employment-related health assessment. MAIN OUTCOME MEASURES:PCOS prevalence, overall and by ethnicity in a large medically unbiased population, including Caucasian (White), Mongolic or Asian (Buryat), and mixed ethnicity individuals living in similar geographic and socioeconomic conditions for centuries. RESULTS:PCOS was diagnosed in 165/1134 (14.5%) women who had a complete evaluation for PCOS. Based on the probabilities for PCOS by clinical presentation observed in the cohort of women who had a complete evaluation, we also estimated the weight-adjusted prevalence of PCOS in 264 women with an incomplete evaluation: 46.2 or 17.5%. Consequently, the total prevalence of PCOS in the population was 15.1%, higher among Caucasians and women of mixed ethnicity compared to Asians (16.0% and 21.8% vs 10.8%, Pz < .05). CONCLUSION:We observed a 15.1% prevalence of PCOS in our medically unbiased population of premenopausal women. In this population of Siberian premenopausal women of Caucasian, Asian, and mixed ethnicity living in similar geographic and socioeconomic conditions, the prevalence was higher in Caucasian or mixed than Asian women. These data highlight the need to assess carefully ethnic-dependent differences in the frequency and clinical manifestation of PCOS.

The parameters of oxidative damage of DNA, proteins, as well as the parameters of the thiol-disulfide system and C-reactive protein in adolescent girls and boys with exogenous constitutional obesity (ECO) were evaluated. In girls and boys with obesity, the levels of 8-hydroxy-2’-deoxyguanosine (marker of DNA destruction) were higher than in controls. Evaluation of the activity of the thiol-disulfide system revealed increased levels of oxidized glutathione (GSSG) and decreased levels of the reduced glutathione (GSH) and GSSG ratio (GSH/GSSG) in adolescents with ECO regardless of the sex in comparison with the control. C-reactive protein was also higher in the ECO groups regardless of the sex. The levels of glutathione peroxidase in obese boys were higher than in girls. In view of the revealed shifts, corrective measures with the prescription of drugs with antioxidant properties are recommended in adolescents with ECO to stabilize the indices.

We analyzed the state of neuroendocrine regulation and LPO-antioxidant defense systems in reproductive age women with metabolic syndrome (MetS), representatives of the Russian and Buryat ethnic groups. Compared to the corresponding control groups, women from the Russian ethnic group with MetS had elevated levels of thyroid-stimulating hormone and free androgen index (FAI) and reduced levels of sex hormone-binding globulin, while women from the Buryat ethnic group had increased levels of prolactin and FAI. Changes in the LPO system in women of the Russian ethnic group with MetS consisted in an increase in the levels of substrates with double bonds, TBA-reactive substances, and fat-soluble vitamins. Buryat women with MetS had a higher content of primary oxidation products and reduced levels of glutathione. The results of the study indicate a hyperandrogenic shift in the neuroendocrine regulation system, as well as compensatory influences from different parts of the antioxidant defense system in women of reproductive age with MetS, depending on their ethnicity. These findings indicate the need for assessing and monitoring the levels of these metabolites in women with MetS, considering their ethnicity.

The tissue preparations of the pelvic veins obtained during laparoscopy were examined. The expression of markers of proliferation (Ki-67), apoptosis (p53), and angiogenesis (CD31, CD34), as well as estrogen and progesterone receptors in women with pelvic varicose veins was assessed by the immunohistochemical method. A decrease in the median expression of the proliferation marker (Ki-67) and estrogen and progesterone receptors and simultaneous increase in the expression of apoptosis marker (p53) and activation of angiogenesis processes (markers CD31 and CD34) were observed with increasing the severity of the disease. These data extend our understanding of the pathogenetic mechanisms of pelvic varicose veins and contribute to the development of methods of pathogenetically based targeted therapy.

Understanding how gut flora interacts with oxidative stress has been the subject of significant research in recent years. There is much evidence demonstrating the existence of the microbiome–oxidative stress interaction. However, the biochemical basis of this interaction is still unclear. In this narrative review, possible pathways of the gut microbiota and oxidative stress interaction are presented, among which genetic underpinnings play an important role. Trimethylamine-N-oxide, mitochondria, short-chain fatty acids, and melatonin also appear to play roles. Moreover, the relationship between oxidative stress and the gut microbiome in obesity, metabolic syndrome, chronic ethanol consumption, dietary supplements, and medications is considered. An investigation of the correlation between bacterial community features and OS parameter changes under normal and pathological conditions might provide information for the determination of new research methods. Furthermore, such research could contribute to establishing a foundation for determining the linkers in the microbiome–OS association.

The levels of endothelins were assessed in menopausal women with arterial hypertension (AH) and type 2 diabetes mellitus (T2DM) in the acute phase of the moderate COVID-19. Women under observation (age 45-69 years) were divided into two groups. Control group consisted of women (n=16) who did not have COVID-19, were not vaccinated, and had no antibodies to SARS-CoV-2 (IgG). The main group included women (n=63) in the acute phase of the moderate COVID-19 accompanied by pneumonia. According to the clinical and anamnestic data analysis, the main group was divided into subgroups: without AH and T2DM (n=21); with AH and without T2DM (n=32); and with AH and T2DM (n=10). The parameters of clinical blood analysis, as well as endothelin-1, endothelin-2, and endothelin-3 levels were assessed. In women with a moderate COVID-19, the endothelin-1 and endothelin-2 levels were increased compared to the control regardless of AH and T2DM status. We found no statistically significant differences in the studied parameters of endothelial dysfunction between the subgroups of menopausal women in the acute phase of the moderate COVID-19.

We compared alpha diversity indices of the intestinal microbiota in adolescents with obesity and normal body weight, taking into account their ethnicity. Intestinal biocenosis was studied by metasequencing of amplicon libraries of V3-V4 fragments of the 16S rRNA gene. The alpha diversity of the microbiota was assessed using classical and alternative indices. Statistically significant differences in intestinal microbiota were observed between Russians with obesity and Buryats with normal body weight, as well as between Russians with obesity and Buryats with obesity when assessing the Shannon—Weaver, Chao1 indices, Faith phylogenetic diversity index, ACE, Fisher, Gini coefficient, Margalef, and Menkhinik indices. It was shown that alpha diversity indices can be used to assess significance of differences and variability of the intestinal microbiota in multifactorial diseases such as obesity in adolescents; however, the scope of application of the criteria should be considered.

Background: This study aimed to evaluate the state of the pituitary-ovarian link of the neuroendocrine regulation system in women of reproductive age with OH of the main ethnic groups of the Baikal region. Methods and Results: Groups of women with OH of Buryat (n=35) and Caucasian (n=97) ethnic groups were formed. Data from somatically healthy women of Buryat (n=42) and Caucasian (n=87) ethnic groups were used for comparison. A comparative characterization of clinical data and indicators of the pituitary-ovarian link of the neuroendocrine regulation system was carried out. ELISA methods were used to determine thyroid-stimulating hormone (TSH), prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), 17-OH-progesterone (17-OH-Pg), and sex hormone-binding globulin (SHBG). Testosterone levels were analyzed by liquid chromatography-mass spectrometry. Buryat ethnic group women with OH had higher values of body weight, BMI, waist and hip circumference, and % fat compared to the corresponding control group. In the group of Caucasian women with OH, higher values of height, systolic blood pressure, and diastolic blood pressure were registered compared to the control group. In Buryat women with OH, higher TSH, anti-Mullerian hormone (AMH), free androgen index (FAI), and dehydroepiandrosterone sulfate (DHEA-S) values were found compared to controls. In the group of Caucasian women with OH, higher values of PRL, AMH, TSH, FAI, 17-OH-Pg, and DHEA-S were registered compared to the control. In Buryat women with OH, LH values were higher only in phase 2 compared to controls. In Caucasian women with OH, LH values increased both in phase 1 and phase 2 compared to controls. Conclusion. A comprehensive analysis of the state of the neuroendocrine regulation system in women of reproductive age with OH showed certain changes in the level of a number of hormones relative to control groups, most pronounced in the group of Caucasian women. At the same time, there were no differences in the studied indicators between ethnic groups with OH. The data obtained indicate the necessity of assessing and controlling the state of the neuroendocrine regulation system in female patients with OH for PCOS prevention and treatment. The ethnic component may have a certain contribution to the realization of further risks of the disease.

The literature review examines the problem of obesity in modern society. It has been shown that obesity aggravates concomitant diseases, increases the probability of developing metabolic disorders and related pathologies, increases the risk of complications and mortality. The secretory function of adipose tissue, its participation in the regulation of biological processes is considered in detail. The concept of carbonyl stress and its components is revealed, the role of carbonyl compounds in the body is described, the metabolic pathways leading to the formation of carbonyl reaction products are shown, the participation of free radicals in these metabolic pathways is noted. The mechanisms of pathogenesis associated with the development of carbonyl stress in obesity are discussed; the greatest contribution to the development of car bonyl pathology in obesity is made by two types of processes: lipid peroxidation reactions resulting in the formation of carbonyl products of lipoperoxidation and the processes activated by hyperglycemia (glycolysis, polyol and hexоzamine pathways) leading to the formation of glyoxal, methylglyoxal, and active carbonyl forms of glucose. The question of the contribution of advanced glycation end products (AGEs) and advanced oxidation protein products (AOРР) to the development of carbonyl pathology in obesity remains controversial. It is assumed that AGEs and AOРР levels depend on the severity of obesity and the development of metabolic syndrome.

We studied the effects of visceral obesity induced by a high-calorie diet and health-improving variants of its correction on morphological characteristics of the muscle tissue in male Wistar rats. At stage I, the rats received standard (StD) or high-calorie diet (HCD) for 8 weeks. At stage II, the animals were divided into the following subgroups: no correction (StD and HCD), switching from HCD to StD (HCD/StD) and/or connection of physical activity in the form of treadmill running (StD+running, HCD+running, and HCD/StD+running) for the next 8 weeks. Diet-induced visceral obesity was shown to result in a decrease in the weight of the triceps surae muscle, fatty infiltration, intracellular edema, partial lysis of contractile elements, weak inflammatory response, and decreased muscle fiber area on cross section. Treadmill running (HCD+running) exacerbates the morphological changes, but returns muscle fiber area to normal. Correction of visceral obesity and relative normalization of muscle tissue structure was noted when switching to a standard diet (HCD/StD and HCD/StD+running).

This literature review was compiled according to the data of search engines PubMed, eLIBRARY.RU, Google Scholar using key words influenza, cytokines, children. The article highlights the participation of pro-inflammatory and antiinflammatory cytokines in the pathogenesis of influenza, compares the cytokine profile in different strains of the virus, with concomitant pathology, as well as attempts to find an answer to the question: “Why are young children more susceptible to this infection?” The article contains information about the creation of express systems for diagnosing cytokine storm in patients with influenza and other acute respiratory viral infections, taking into account a complex of clinical and laboratory data that comes to the aid of a practicing physician. It should be noted that there are different opinions among authors regarding the early markers of severe and complicated influenza in childhood. This information makes the topic of studying the significance of cytokines in influenza in children relevant, but it requires continuation and clarification of knowledge on this issue.

The assessment of endothelial dysfunction and free radical homeostasis parameters were performed in 92 women, aged 45 to 69 years, divided into the following groups: women without COVID-19 (unvaccinated, no antibodies, control); women with acute phase of COVID-19 infection (main group, COVID-19+); 12 months post COVID-19+; women with anti-SARS-CoV-2 IgG with no symptoms of COVID-19 in the last 12 months (asymptomatic COVID-19). Compared to the control, patients of the main group had lower glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities, decreased advanced glycation end products (AGEs) level, higher glutathione reductase (GR) activity, and higher glutathione S transferases pi (GSTpi), thiobarbituric acid reactants (TBARs), endothelin (END)-1, and END-2 concentrations (all p ≤ 0.05). The group with asymptomatic COVID-19 had lower 8-OHdG and oxidized glutathione (GSSG) levels, decreased total antioxidant status (TAS), and higher reduced glutathione (GSH) and GSH/GSSG levels (all p ≤ 0.05). In the group COVID-19+, as compared to the group without clinical symptoms, we detected lower GPx and SOD activities, decreased AGEs concentration, a higher TAS, and greater GR activity and GSTpi and TBARs concentrations (all p ≤ 0.05). The high content of lipid peroxidation products 12 months post COVID-19+, despite decrease in ENDs, indicates long-term changes in free radical homeostasis. These data indicate increased levels of lipid peroxidation production contribute, in part, to the development of free radical related pathologies including long-term post COVID syndrome.