COVID-19, Oxidative Stress and Male Reproduction: Possible Role of Antioxidants

Zinc as a Possible Critical Element to Prevent Harmful Effects of COVID-19 on Testicular Function: a Narrative Review

Research into innovative non-pharmacological therapeutic routes via the utilization of natural elements like zinc (Zn) has been motivated by the discovery of new severe acute respiratory syndrome-related coronavirus 2 (SARS-COV2) variants and the ineffectiveness of certain vaccination treatments during COVID-19 pandemic. In addition, research on SARS-COV-2's viral cellular entry and infection mechanism has shown that it may seriously harm reproductive system cells and impair testicular function in young men and adolescents, which may lead to male infertility over time. In this context, we conducted a narrative review to give an overview of the data pertaining to Zn's critical role in testicular tissue, the therapeutic use of such micronutrients to enhance male fertility, as well as in the potential mitigation of COVID-19, with the ultimate goal of elucidating the hypothesis of the potential use of Zn supplements to prevent the possible harmful effects of SARS-COV2 infection on testis physiological function, and subsequently, on male fertility.

Association between post-COVID-19 conditions and male semen quality in Japan: A descriptive investigation

Some reports suggest that coronavirus disease 2019 (COVID-19) may affect male reproductive function. There is also concern in Japan that COVID-19 may contribute to the pre-existing decline in male fertility; however, no studies have investigated the effects of COVID-19 on male reproductive function. In this study, we aimed to analyze the semen quality of men who had recovered from COVID-19. Male patients who had recovered from COVID-19 between February 2020 and September 2021 were recruited for this study. Participants were sent a semen collection kit; they were asked to collect semen at home and deliver it to a laboratory at Osaka University. We used these samples to analyze sperm concentration, total sperm count, and semen volume. In total, 125 participants were included in this study. The median age of all patients was 46 years (interquartile range (IQR): 38-52 years). The severity of COVID-19 was mild in 80 patients; 19 were moderate I, 22 were moderate II, and four were severe. The median semen volume was 2.5 mL (IQR: 1.8-3.1), the median sperm concentration was 98.9 million/mL (IQR: 43.8-162.2), and the median total sperm count was 212.1 million (IQR: 89.7-368.2). In a previous study in Japan, the median sperm count in adult men was reported to be 201 million. Participants in our study did not have lower sperm counts than this, despite their older age. Our results suggest that the long-term effects of COVID-19 on spermatogenesis are minimal.

Redox Biomarkers - An Effective Tool for Diagnosing COVID-19 Patients and Convalescents

Aim

COVID-19 triggers the overproduction of reactive oxygen species (ROS) which, in combination with a weakened antioxidant barrier, can lead to protein oxidation and lipid peroxidation. The aim of this study was to evaluate enzymatic and non-enzymatic antioxidants, the overall redox potential, and protein and lipid peroxidation products in COVID-19 patients, convalescents, and healthy subjects, and to the determine the diagnostic applicability of these parameters in COVID-19 patients.

Materials and Methods

The study involved 218 patients with COVID-19, 69 convalescents, and 48 healthy subjects who were selected for the research based on age and sex. The study was conducted between 20 February 2021 and 20 November 2021 in Białystok, Poland. The antioxidant barrier, redox status, and oxidative damage products were assessed in serum/plasma samples with the use of colorimetric and spectrophotometric assays.

Results

Glutathione reductase (GR) activity was higher, whereas total antioxidant capacity (TAC) was lower in COVID-19 patients than in convalescents (p<0.0001) and the control group (p<0.0001). The concentrations of advanced glycation end products (AGEs), advanced oxidation protein products (AOPP), 4-hydroxynonenal (4-HNE), and malondialdehyde (MDA) were higher in COVID-19 patients (p<0.0001) and convalescents (p<0.0001) than in the control group. AGEs were the most effective diagnostic biomarker for differentiating COVID-19 patients from the control group (AUC=0.9971) and convalescents from the control group (AUC=1.000).

Conclusion

An infection with the SARS-CoV-2 disrupts the redox balance and increases protein oxidation and lipid peroxidation. AGEs fulfill the criteria for a potential diagnostic biomarker in COVID-19 patients and convalescents.

Significance of nitrosative stress and glycoxidation products in the diagnosis of COVID-19

Nitrosative stress promotes protein glycoxidation, and both processes can occur during an infection with the SARS-CoV-2 virus. Therefore, the aim of this study was to assess selected nitrosative stress parameters and protein glycoxidation products in COVID-19 patients and convalescents relative to healthy subjects, including in reference to the severity of COVID-19 symptoms. The diagnostic utility of nitrosative stress and protein glycoxidation biomarkers was also evaluated in COVID-19 patients. The study involved 218 patients with COVID-19, 69 convalescents, and 48 healthy subjects. Nitrosative stress parameters (NO, S-nitrosothiols, nitrotyrosine) and protein glycoxidation products (tryptophan, kynurenine, N-formylkynurenine, dityrosine, AGEs) were measured in the blood plasma or serum with the use of colorimetric/fluorometric methods. The levels of NO (p = 0.0480), S-nitrosothiols (p = 0.0004), nitrotyrosine (p = 0.0175), kynurenine (p < 0.0001), N-formylkynurenine (p < 0.0001), dityrosine (p < 0.0001), and AGEs (p < 0.0001) were significantly higher, whereas tryptophan fluorescence was significantly (p < 0.0001) lower in COVID-19 patients than in the control group. Significant differences in the analyzed parameters were observed in different stages of COVID-19. In turn, the concentrations of kynurenine (p < 0.0001), N-formylkynurenine (p < 0.0001), dityrosine (p < 0.0001), and AGEs (p < 0.0001) were significantly higher, whereas tryptophan levels were significantly (p < 0.0001) lower in convalescents than in healthy controls. The ROC analysis revealed that protein glycoxidation products can be useful for diagnosing infections with the SARS-CoV-2 virus because they differentiate COVID-19 patients (KN: sensitivity-91.20%, specificity-92.00%; NFK: sensitivity-92.37%, specificity-92.00%; AGEs: sensitivity-99,02%, specificity-100%) and convalescents (KN: sensitivity-82.22%, specificity-84.00%; NFK: sensitivity-82,86%, specificity-86,00%; DT: sensitivity-100%, specificity-100%; AGE: sensitivity-100%, specificity-100%) from healthy subjects with high sensitivity and specificity. Nitrosative stress and protein glycoxidation are intensified both during and after an infection with the SARS-CoV-2 virus. The levels of redox biomarkers fluctuate in different stages of the disease. Circulating biomarkers of nitrosative stress/protein glycoxidation have potential diagnostic utility in both COVID-19 patients and convalescents.

SARS-CoV-2 infection negatively impacts on the quality of embryos by delaying early embryonic development

BACKGROUND

The COVID-19 pandemic is an unprecedented health crisis that has affected in vitro fertilization practices globally. Previous studies have shown that SARS-CoV-2 impacts the quality of embryos by inducing an immunological response in infertile patients. In this study, the early embryonic development of SARS-CoV-2-infected infertile patients was investigated.

METHODS

Sixty-five SARS-CoV-2 infected infertile patients and 258 controls were involved in this study. The major outcome parameters for the cycle were analyzed, including the number of oocytes, maturation oocytes, available embryos per cycle, and embryo morpho kinetic characteristics.

RESULTS

From SARS-CoV-2 infection until oocyte retrieval, it took an average of 6.63 days. The results revealed that the number of oocytes and high-quality embryos on day 3 dramatically reduced in SARS-CoV-2-infected infertile patients. SARS-CoV-2 was detected in the follicular fluid of three infertile patients. SARS-CoV-2 infection had negatively impacted the number of oocytes in multivariate linear regression models. The early embryonic development in the SARS-CoV-2 infection group had a noticeable delay from the six-cell stage to blastocyst stage.

CONCLUSIONS

SARS-CoV-2 infection reduced the number of oocytes and high-quality embryos on day 3. It delays the early embryonic development from the six-cell stage to blastocyst stage and has a negative impact on the quality of embryos.

Potential Beneficial Effects of Naringin and Naringenin on Long COVID-A Review of the Literature

Coronavirus disease 2019 (COVID-19) caused a severe epidemic due to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Recent studies have found that patients do not completely recover from acute infections, but instead, suffer from a variety of post-acute sequelae of SARS-CoV-2 infection, known as long COVID. The effects of long COVID can be far-reaching, with a duration of up to six months and a range of symptoms such as cognitive dysfunction, immune dysregulation, microbiota dysbiosis, myalgic encephalomyelitis/chronic fatigue syndrome, myocarditis, pulmonary fibrosis, cough, diabetes, pain, reproductive dysfunction, and thrombus formation. However, recent studies have shown that naringenin and naringin have palliative effects on various COVID-19 sequelae. Flavonoids such as naringin and naringenin, commonly found in fruits and vegetables, have various positive effects, including reducing inflammation, preventing viral infections, and providing antioxidants. This article discusses the molecular mechanisms and clinical effects of naringin and naringenin on treating the above diseases. It proposes them as potential drugs for the treatment of long COVID, and it can be inferred that naringin and naringenin exhibit potential as extended long COVID medications, in the future likely serving as nutraceuticals or clinical supplements for the comprehensive alleviation of the various manifestations of COVID-19 complications.

The possible role of nuclear factor erythroid-2-related factor 2 activators in the management of Covid-19

COVID-19 is caused by a novel SARS-CoV-2 leading to pulmonary and extra-pulmonary manifestations due to oxidative stress (OS) development and hyperinflammation. COVID-19 is primarily asymptomatic though it may cause acute lung injury (ALI), acute respiratory distress syndrome (ARDS), systemic inflammation, and thrombotic events in severe cases. SARS-CoV-2-induced OS triggers the activation of different signaling pathways, which counterbalances this complication. One of these pathways is nuclear factor erythroid 2-related factor 2 (Nrf2), which induces a series of cellular interactions to mitigate SARS-CoV-2-mediated viral toxicity and OS-induced cellular injury. Nrf2 pathway inhibits the expression of pro-inflammatory cytokines and the development of cytokine storm in COVID-19. Therefore, Nrf2 activators may play an essential role in reducing SARS-CoV-2 infection-induced inflammation by suppressing NLRP3 inflammasome in COVID-19. Furthermore, Nrf2 activators can attenuate endothelial dysfunction (ED), renin-angiotensin system (RAS) dysregulation, immune thrombosis, and coagulopathy. Thus this mini-review tries to clarify the possible role of the Nrf2 activators in the management of COVID-19. Nrf2 activators could be an effective therapeutic strategy in the management of Covid-19. Preclinical and clinical studies are recommended in this regard.

COVID-19 and primary wound healing: A new insights and advance

With the outbreak and pandemic of coronavirus disease-2019 (COVID-19), a huge number of people died of it. Apart from lung injuries, multiple organs have been confirmed to be impaired. In COVID-19 time, primary wound healing processes always prolong, however, its possible underlying mechanisms are still unclear. Therefore, to overcome this clinical problem, clarifying its underlying mechanisms clearly is necessary and urgently needed. In this review, we summarized that COVID-19 can prolong primary wound healing by inducing excessive inflammation and oxidative stress, disturbing immune system and haematological system, as well as influencing the functions and viability of epidermal stem cells (ESCs). Otherwise, we summarized that the strict control measures of blocking up COVID-19 pandemic can also have side effects on primary wound healing process.

SARS-CoV-2 infection (COVID-19) and male fertility: Something we should be worried about?

As of 2021, roughly 5 million deaths were linked to SARS-CoV-2 infection based on World Health Organization estimates. The pandemic takes its staggering death toll, severely affecting the healthcare systems and leading to detrimental implications globally. While the severe impact on the respiratory system is well-established, the exact effect on male reproduction is still largely uncharted territory. When it comes to gender, men appear more vulnerable compared to women. Increasing evidence suggests that COVID-19 adversely affects spermatogenesis and hormonal balance in diverse ways. Semen parameters seem to be compromised at least temporarily, while long-term worsening needs to be clarified in studies with extended follow-up. For the time being, no data support the adverse effect of COVID-19 vaccines on a male's reproductive health. In the present article, we examine the available literature and briefly discuss the impact of the virus on reproduction and fertility. We further provide a comprehensive overview of the current status of vaccination and its potential effect on male fertility. Ultimately, we address the need for future well-designed large-scale trials before drawing definite conclusions on the exact impact of the virus on a male's fecundity.

The role of death receptor signaling pathways in mouse Sertoli cell avoidance of apoptosis during LPS- and IL-18-induced inflammatory conditions

Lipopolysaccharide (LPS) triggers infectious acute inflammation, and interleukin (IL)-18 is an inflammasome-mediated cytokine. We previously demonstrated that endogenous IL-18 induces testicular germ cell apoptosis during acute inflammation when plasma IL-18 levels are high. Additionally, high-dose recombinant IL-18 (rIL-18) induced Leydig cell apoptosis. The blood-testis barrier formed by Sertoli cells protects testicular germ cells from both exogenous and endogenous harmful substances. However, the impact of LPS and IL-18 on Sertoli cells remained unclear. We stimulated TM4 cells, a mouse Sertoli cell line, with LPS (200 or 1000 ng/mL) or rIL-18 (0.1-100 ng/mL) at levels that induced Leydig cell apoptosis in our previous study and assessed caspase 3 cleavage and the mRNA expression of inflammatory cytokines and markers of apoptotic pathways (Tnfr1, Fasl, Fas, Fadd) after stimulation. Il6 mRNA was increased by LPS stimulation. Tnfα mRNA was increased by 200 ng/mL LPS but not 1000 ng/mL LPS. Fas was increased, but Fasl was decreased, by LPS. LPS had little influence on Tnfr1 or Fadd mRNA expression and did not induce apoptosis. Il18 mRNA was not increased, and Il18r1 was significantly decreased following LPS treatment. Treatment with rIL-18 increased Il18r1 mRNA and induced inflammation, but decreased Tnfr1 and had little influence on apoptosis, as indicated by Tnfα, Fasl, Fas, Fadd and cleaved caspase 3. These results suggested that Sertoli cells do not easily undergo apoptosis despite strong inflammatory stimuli. Additionally, Sertoli cells may resist inflammation and play a larger role in protecting testicular homeostasis than other component cells of the testis.

COVID-19 and Male Infertility: Is There a Role for Antioxidants?

Coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), jeopardizes male fertility because of the vulnerability of the male reproductive system, especially the testes. This study evaluates the effects of the virus on testicular function and examines the potential role of antioxidants in mitigating the damage caused by oxidative stress (OS). A comprehensive PubMed search examined exocrine and endocrine testicular function alteration, the interplay between OS and COVID-19-induced defects, and the potential benefit of antioxidants. Although the virus is rarely directly detectable in sperm and testicular tissue, semen quality and hormonal balance are affected in patients, with some changes persisting throughout a spermatogenesis cycle. Testicular pathology in deceased patients shows defects in spermatogenesis, vascular changes, and inflammation. Acute primary hypogonadism is observed mainly in severely infected cases. Elevated OS and sperm DNA fragmentation markers suggest redox imbalance as a possible mechanism behind the fertility changes. COVID-19 vaccines appear to be safe for male fertility, but the efficacy of antioxidants to improve sperm quality after infection remains unproven due to limited research. Given the limited and inconclusive evidence, careful evaluation of men recovering from COVID-19 seeking fertility improvement is strongly recommended.

Insights into the Scenario of SARS-CoV-2 Infection in Male Reproductive Toxicity

COVID-19 has become a significant public health concern that has catastrophic consequences for society. Some preliminary evidence suggests that the male reproductive system may be an infection target for SARS-CoV-2. SARS-CoV-2 may be transmitted sexually, according to preliminary research. Testicular cells exhibit a high level of the angiotensin-converting enzyme 2 (ACE2) receptor, which enhances the entry of the SARS-CoV-2 into host cells. Some instances of COVID-19 have been documented to exhibit hypogonadism during the acute stage. Furthermore, systemic inflammatory reactions triggered by SARS-CoV-2 infection may cause oxidative stress (OS), which has been shown to have profoundly deleterious consequences on testicular functioning. This work gives a clear picture of how COVID-19 may affect male reproductive systems and calls attention to the many unanswered questions about the mechanisms by which this virus can be linked to men’s health and fertility.

Semen quality changes during infection and recovery phases of mild-to-moderate COVID-19 in reproductive-aged patients: a prospective case series

BACKGROUND

Despite the documented effects of the coronavirus disease 2019 (COVID-19) on spermatogenesis, the reversibility of these effects is uncertain. We aimed to assess the changes of sperm quality between the infection and recovery phases of COVID-19 in reproductive-aged men. The semen quality of men with mild-to-moderated COVID-19 (defined by the degrees of symptoms and chest involvement on computed tomography) was studied during October, 2020-May, 2021 at our hospital. Two semen samples were analyzed at timings estimated to represent spermatogenic cycles during the infection and recovery phases of COVID-19.

RESULTS

A total of 100 patients were included with mean ± SD (range) age of 24.6 ± 3.3 (21-35) years. During infection, 33% of patients had abnormal semen quality. However, a significant reduction was found in this abnormality from 33 to 11% (P < 0.001) after recovery from infection. In a comparison of the two semen analyses, there were significant improvements in the mean values of sperm progressive motility (P =0.043) and normal morphology (P < 0.001). However, the mean sperm concentration showed a statistically insignificant increase (P = 0.844).

CONCLUSIONS

In reproductive-aged patients with mild-to-moderate COVID-19, the effects on seminal quality were recoverable, represented by significant improvements in the means of progressive sperm motility and normal morphology between the infection and recovery phases of COVID-19.

TRIAL REGISTRATION

ClinicalTrials, NCT04595240 .

Is Nuclear Factor Erythroid 2-Related Factor 2 a Target for the Intervention of Cytokine Storms?

The term "cytokine storm" describes an acute pathophysiologic state of the immune system characterized by a burst of cytokine release, systemic inflammatory response, and multiple organ failure, which are crucial determinants of many disease outcomes. In light of the complexity of cytokine storms, specific strategies are needed to prevent and alleviate their occurrence and deterioration. Nuclear factor erythroid 2-related factor 2 (NRF2) is a CNC-basic region-leucine zipper protein that serves as a master transcription factor in maintaining cellular redox homeostasis by orchestrating the expression of many antioxidant and phase II detoxification enzymes. Given that inflammatory response is intertwined with oxidative stress, it is reasonable to assume that NRF2 activation limits inflammation and thus cytokine storms. As NRF2 can mitigate inflammation at many levels, it has emerged as a potential target to prevent and treat cytokine storms. In this review, we summarized the cytokine storms caused by different etiologies and the rationale of interventions, focusing mainly on NRF2 as a potential therapeutic target.