Oxidative Stress in Autoimmune Diseases: An Under Dealt Malice

Attenuation of adjuvant-induced arthritis with carnosic acid by inhibiting mPGES-1, COX-2, and bone loss in male SD rats

OBJECTIVE

Rheumatoid arthritis (RA), a chronic inflammatory disease, is characterized by joint swelling, cartilage erosion, and bone destruction. This study investigated the therapeutic efficacy of Carnosic acid (CA), a natural compound with anti-inflammatory and antioxidant properties, in an adjuvant-induced arthritis model.

METHODS

Paw swelling and arthritis index were measured. Oxidative stress markers, including lipid peroxidation and antioxidant enzyme levels, were assessed. Synovial tissue was analyzed for pro-inflammatory markers using real-time Q-PCR and Western blotting. The expression of mPGES-1 was determined by Western blotting. Peripheral neuropathic pain was assessed using cold and mechanical allodynia tests. Bone loss was quantitatively assessed through microcomputed tomography (μCT) scanning of femurs and X-ray radiography. Indomethacin-induced gastric ulcers were evaluated. Molecular docking studies were conducted to analyze the binding affinity of CA to mPGES-1.

RESULTS

The CA treatment not only demonstrated a significant reduction in joint inflammation and paw swelling but also mitigated oxidative stress and improved the antioxidant defence system. CA inhibited microsomal prostaglandin E synthase-1 (mPGES-1) expression and the expression of pro-inflammatory molecules such as inducible nitric oxide synthase (iNOS) and cyclooxygenases-2 (COX-2), thus attenuating the arthritis symptoms without severe gastrointestinal side effects. Additionally, it inhibited the expression of pro-inflammatory molecules such as iNOS and COX-2, contributing to the reduction of arthritis symptoms. Notably, CA treatment prevented the common side effects of traditional RA treatments like corticosteroids and non-steroidal anti-inflammatory drugs (NSAIDs), including weight loss, bone degradation, and gastric ulcers.

CONCLUSIONS

These findings suggest that CA, through specific enzyme inhibition, offers a compelling alternative therapeutic approach for RA. Further research is warranted to explore the potential of CA in other arthritis models and its suitability for human RA treatment.

Ischemia-modified albumin in rheumatic diseases: A systematic review and meta-analysis

INTRODUCTION

The identification of novel, easily measurable disease biomarkers might enhance the diagnosis and management of patients with rheumatic diseases (RDs). We conducted a systematic review and meta-analysis of ischemia-modified albumin (IMA), a marker of oxidative stress, acidosis, and ischemia, in RD patients and healthy controls.

METHODS

We searched PubMed, Web of Science, and Scopus from inception to January 15, 2024. The risk of bias and the certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist and GRADE, respectively.

RESULTS

In 20 studies investigating a total of 1188 RD patients (mean age 45 years, 64% females) and 981 healthy controls (mean age 44 years, 66% females), RD patients had significantly higher IMA concentrations when compared to controls (standard mean difference, SMD = 0.50, 95% CI: 0.18-0.83, p = .003; I2 = 92.4%, p < .001; low certainty of evidence). In subgroup analysis, the pooled SMD was significantly different in studies investigating ankylosing spondylitis (p < .001), Behçet's disease (p < .001), and rheumatoid arthritis (p = .033), but not familial Mediterranean fever (p = .48). Further associations were observed between the pooled SMD and the broad classification of autoimmune and/or autoinflammatory diseases, the study country, and the method used to measure IMA.

CONCLUSION

Our study suggests that IMA is a promising biomarker of oxidative stress, acidosis, and ischemia, as it can effectively discriminate between patients with different types of RDs and healthy controls. Our results warrant confirmation in longitudinal studies of patients with different types of RDs and different ethnicities (PROSPERO registration number: CRD42024509126).

Association of autoimmune and allergic diseases with senile cataract: a bidirectional two-sample Mendelian randomization study

Background

Many observational studies have been reported that patients with autoimmune or allergic diseases seem to have a higher risk of developing senile cataract, but the views are not consistent. In order to minimize the influence of reverse causality and potential confounding factors, we performed Mendelian Randomization (MR) analysis to investigate the genetic causal associations between autoimmune, allergic diseases and senile cataract.

Methods

Single nucleotide polymorphisms associated with ten common autoimmune and allergic diseases were obtained from the IEU Open genome-wide association studies (GWAS) database. Summary-level GWAS statistics for clinically diagnosed senile cataract were obtained from the FinnGen research project GWAS, which consisted of 59,522 individuals with senile cataracts and 312,864 control individuals. MR analysis was conducted using mainly inverse variance weighted (IVW) method and further sensitivity analysis was performed to test robustness.

Results

As for ten diseases, IVW results confirmed that type 1 diabetes (OR = 1.06; 95% CI = 1.05-1.08; p = 2.24×10-12), rheumatoid arthritis (OR = 1.05; 95% CI = 1.02-1.08; p = 1.83×10-4), hypothyroidism (OR = 2.4; 95% CI = 1.42-4.06; p = 1.12×10-3), systemic lupus erythematosus (OR = 1.02; 95% CI = 1.01-1.03; p = 2.27×10-3), asthma (OR = 1.02; 95% CI = 1.01-1.03; p = 1.2×10-3) and allergic rhinitis (OR = 1.07; 95% CI = 1.02-1.11; p = 2.15×10-3) were correlated with the risk of senile cataract. Celiac disease (OR = 1.04; 95% CI = 1.01-1.08; P = 0.0437) and atopic dermatitis (OR = 1.05; 95% CI = 1.01-1.10; P = 0.0426) exhibited a suggestive connection with senile cataract after Bonferroni correction. These associations are consistent across weighted median and MR Egger methods, with similar causal estimates in direction and magnitude. Sensitivity analysis further proved that these associations were reliable.

Conclusions

The results of the MR analysis showed that there were causal relationships between type 1 diabetes, rheumatoid arthritis, hypothyroidism, systemic lupus erythematosus, asthma, allergic rhinitis and senile cataract. To clarify the possible role of autoimmune and allergy in the pathophysiology of senile cataract, further studies are needed.

Oxidative Stress is a New Avenue for Treatment of Neuropsychiatric Disorders: Hype of Hope?

The biochemical integrity of the brain is critical in maintaining normal central nervous system (CNS) functions. One of the factors that plays an important role in causing biochemical impairment of the brain is known as oxidative stress. Oxidative stress is generally defined as the excessive formation of free radicals relative to antioxidant defenses. The brain is particularly susceptible to oxidative stress because of its high oxygen consumption and lipid-rich content. Therefore, oxidative stress damage is associated with abnormal CNS function. Psychiatric disorders are debilitating diseases. The underlying pathophysiology of psychiatric disorders is poorly defined and may involve the interplay of numerous clinical factors and mechanistic mechanisms. Considerable evidence suggests that oxidative stress plays a complex role in several neuropsychiatric disorders, including anxiety, bipolar disorder, depression, obsessivecompulsive disorder, panic disorder, and schizophrenia. To address these issues, we reviewed the literature and considered the role of oxidative stress as one of the first pathological changes in the course of neuropsychiatric disorders, which should receive more attention in future research.

Variations of Redox Balance in Different Stages of Childhood Immune Thrombocytopenic Purpura

BACKGROUND

 Few previous studies indicated the role of oxidative stress in the pathogenesis of childhood idiopathic thrombocytopenic purpura (ITP), but there are little data regarding changes in redox balance in different forms of the disease, and changes after therapeutic procedures. We aimed to investigate the values of pro-oxidants and antioxidative capacity in various forms of ITP before and after the applying therapy.

MATERIALS AND METHODS

 The research included 102 children, classified into the following groups: (1) newly diagnosed ITP (ndITP), (2) persistent ITP, (3) chronic ITP (chITP), and (4) control groups: (A) healthy control and (B) previously experienced ITP-healthy children who had been suffering from ITP earlier. During the clinical assessment, a blood sample was taken from the patients, from which the value of pro-oxidants (index of lipid peroxidation measured as TBARS, nitrites [NO2 -], as measurement of nitric oxide [NO] production, superoxide anion radical [O2 -], and hydrogen peroxide [H2O2]) and the capacity of antioxidant protection (activity of superoxide dismutase and catalase, and quantity of reduced glutathione) were determined spectrophotometrically.

RESULTS

 Our results demonstrated that values of pro-oxidants, especially reflected through the TBARS and O2 -, were the highest in the ndITP and exacerbated chITP groups. Also, the activity of the endogenous antioxidative defense system was the lowest in these groups. Intravenous immunoglobulin therapy in the ndITP group exerted the most prominent effect on the redox balance.

CONCLUSION

 It can be concluded that severity and exacerbation of the ITP are closely related to the redox status.

Oxidative Stress Mediated Therapy in Patients with Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this meta-analysis is to explore all the available literature to obtain updated data about the potential use of antioxidants in the treatment of rheumatoid arthritis (RA) and its ability to reduce disease progression and cardiovascular risk.

METHODS

This systematic review and meta-analysis was performed strictly in accordance with the PRISMA guidelines. English and Chinese databases were searched with a retrieval time up to March 2023. These databases included the PubMed, Embase, Medline Complete, Web of Sciences and Cochrane Collaboration, Wanfang, China National Knowledge Infrastructure, and VIP databases. This literature search was formulated by the two researchers independently. The search strategy consists of reading, collecting the literature, and conducting the preliminary screening. After that, they provide the final selection of the literature according to the inclusion criteria and data extraction. Also, for all studies, the risk bias was assessed to evaluate the quality of the included references. The content of the risk assessment of bias included the following criteria: random allocation method, allocation plan hiding, blind method, completeness of result data, and selectivity of reporting of results, as well as other biases. The main outcomes were clinical efficiency of antioxidant therapy (C-reactive protein, DAS28 score, HAQ, Number of tender joints, etc.) and oxidative stress indicators (catalase, superoxide dismutase, or total antioxidant capacity).

RESULTS

We observed, in most of the studies, the small or moderate effects of antioxidant treatment. The mean effect size is 0.525, and that means that moderate effects were observed in 30 selected RCTs. Also, this effect is confirmed in the 1652 patients with RA with the mean confidence interval of 0.276 (lower limit) and 0.983 (upper limit). Cohen coefficient was calculated at 0.05.

CONCLUSION

The existing evidence is that antioxidants can reduce systemic and local oxidative stress and can reduce damage as the main agent involved in autoimmune diseases such as rheumatoid arthritis.

A Review of the Potential of Nuclear Factor [Erythroid-Derived 2]-like 2 Activation in Autoimmune Diseases

An autoimmune disease is the consequence of the immune system attacking healthy cells, tissues, and organs by mistake instead of protecting them. Inflammation and oxidative stress (OS) are well-recognized processes occurring in association with acute or chronic impairment of cell homeostasis. The transcription factor Nrf2 (nuclear factor [erythroid-derived 2]-like 2) is of major importance as the defense instrument against OS and alters anti-inflammatory activities related to different pathological states. Researchers have described Nrf2 as a significant regulator of innate immunity. Growing indications suggest that the Nrf2 signaling pathway is deregulated in numerous diseases, including autoimmune disorders. The advantageous outcome of the pharmacological activation of Nrf2 is an essential part of Nrf2-based chemoprevention and intervention in other chronic illnesses, such as neurodegeneration, cardiovascular disease, autoimmune diseases, and chronic kidney and liver disease. Nevertheless, a growing number of investigations have indicated that Nrf2 is already elevated in specific cancer and disease steps, suggesting that the pharmacological agents developed to mitigate the potentially destructive or transformative results associated with the protracted activation of Nrf2 should also be evaluated. The activators of Nrf2 have revealed an improvement in the progress of OS-associated diseases, resulting in immunoregulatory and anti-inflammatory activities; by contrast, the depletion of Nrf2 worsens disease progression. These data strengthen the growing attention to the biological properties of Nrf2 and its possible healing power on diseases. The evidence supporting a correlation between Nrf2 signaling and the most common autoimmune diseases is reviewed here. We focus on the aspects related to the possible effect of Nrf2 activation in ameliorating pathologic conditions based on the role of this regulator of antioxidant genes in the control of inflammation and OS, which are processes related to the progression of autoimmune diseases. Finally, the possibility of Nrf2 activation as a new drug development strategy to target pathogenesis is proposed.

Local Myeloid-Derived Suppressor Cells Impair Progression of Experimental Autoimmune Uveitis by Alleviating Oxidative Stress and Inflammation

Purpose

To evaluate the immune regulatory effect of human cord blood myeloid-derived suppressor cells (MDSCs) in experimental autoimmune uveitis (EAU) models.

Methods

MDSCs (1 × 106) or PBS were injected into established C57BL/6 EAU mice via the subconjunctival route on days 0 and 7. The severity of intraocular inflammation was evaluated for up to 3 weeks. Tissue injury and inflammation were analyzed using immunolabelled staining, real-time PCR, and ELISA. In addition, immune cells in draining lymph nodes (LNs) were quantified using flow cytometry.

Results

After 21 days, the clinical scores and histopathological grades of EAU were lower in the MDSCs group compared with the PBS group. Local administration of MDSCs suppressed the oxidative stress and the expression of TNF-α and IL-1β in the retinal tissues. In addition, it inhibited the activation of pathogenic T helper 1 (Th1) and Th17 cells in draining LNs. MDSCs increased the frequency of CD25+ Foxp3+ regulatory T cells and the mRNA expression of IL-10, as an immune modulator.

Conclusions

MDSCs suppressed inflammation and oxidative stress in the retina and inhibited pathogenic T cells in the LNs in EAU. Therefore, ocular administration of MDSCs has therapeutic potential for uveitis.

Etiology and Pathogenesis of Rheumatoid Arthritis-Interstitial Lung Disease

Interstitial lung disease (ILD) is one of the most serious extra-articular complications of rheumatoid arthritis (RA), which increases the mortality of RA. Because the pathogenesis of RA-ILD remains poorly understood, appropriate therapeutic strategies and biomarkers have not yet been identified. Thus, the goal of this review was to summarize and analyze the reported data on the etiology and pathogenesis of RA-ILD. The incidence of RA-ILD increases with age, and is also generally higher in men than in women and in patients with specific genetic variations and ethnicity. Lifestyle factors associated with an increased risk of RA-ILD include smoking and exposure to pollutants. The presence of an anti-cyclic citrullinated peptide antibody, high RA disease activity, and rheumatoid factor positivity also increase the risk of RA-ILD. We also explored the roles of biological processes (e.g., fibroblast-myofibroblast transition, epithelial-mesenchymal transition, and immunological processes), signaling pathways (e.g., JAK/STAT and PI3K/Akt), and the histopathology of RA involved in RA-ILD pathogenesis based on published preclinical and clinical models of RA-ILD in animal and human studies.

Oxidative Stress as a Regulatory Checkpoint in the Production of Antiphospholipid Autoantibodies: The Protective Role of NRF2 Pathway

Oxidative stress is a well-known hallmark of Antiphospholipid Antibody Syndrome (APS), a systemic autoimmune disease characterized by arterial and venous thrombosis and/or pregnancy morbidity. Oxidative stress may affect various signaling pathways and biological processes, promoting dysfunctional immune responses and inflammation, inducing apoptosis, deregulating autophagy and impairing mitochondrial function. The chronic oxidative stress and the dysregulation of the immune system leads to the loss of tolerance, which drives autoantibody production and inflammation with the development of endothelial dysfunction. In particular, anti-phospholipid antibodies (aPL), which target phospholipids and/or phospholipid binding proteins, mainly β-glycoprotein I (β-GPI), play a functional role in the cell signal transduction pathway(s), thus contributing to oxidative stress and thrombotic events. An oxidation-antioxidant imbalance may be detected in the blood of patients with APS as a reflection of disease progression. This review focuses on functional evidence highlighting the role of oxidative stress in the initiation and progression of APS. The protective role of food supplements and Nuclear Factor Erythroid 2-Related Factor 2 (NRF2) activators in APS patients will be summarized to point out the potential of these therapeutic approaches to reduce APS-related clinical complications.

Relationship between Malondialdehyde Serum Levels and Disease Features in a Full Characterized Series of 284 Patients with Systemic Lupus Erythematosus

Malondialdehyde (MDA) is a marker of oxidative stress and antioxidant status. Oxidative stress has been observed to be increased in systemic lupus erythematosus (SLE). Some studies have shown that MDA is upregulated in SLE compared to controls. However, the literature lacks reports regarding the relationship of MDA to disease manifestations. This is relevant since SLE is a multisystemic disease which may affect virtually any organ in the body. In this study, we set out to analyze how MDA serum levels are associated with disease expression in a large series of SLE patients who were fully characterized in clinical and laboratory terms. A total of 284 patients with SLE were recruited. Serum levels of MDA, and the activity (SLEDAI), severity (Katz) and damage index (SLICC-DI) scores, full lipid profile, and carotid subclinical atherosclerosis were assessed. In addition, a full characterization of the complement system was performed in SLE patients' samples. Multivariable linear regression analysis was executed to study the relationship between clinical and laboratory disease characteristics and MDA. A statistically significant negative relationship was found between disease duration and MDA. In contrast, the presence of anti-nucleosome antibodies was positively associated with MDA. Regarding the SLICC-DI areas, both the musculoskeletal domain and the cutaneous domain were significantly related to higher serum MDA values. Furthermore, after adjustment for confounding factors, lower levels of the classical complement pathway, which denotes activation, were associated with higher serum levels of MDA. In conclusion, cumulative musculoskeletal and skin damage in SLE patients is associated with superior serum levels of MDA. In addition, activation of the complement system is also related to higher circulating MDA levels.

Measurement of superoxide dismutase: clinical usefulness for patients with anti-neutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

To investigate the clinical usefulness of serum superoxide dismutase (SOD) measurement in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

METHODS

In this single-center retrospective study, demographic data, serum SOD levels, erythrocyte sedimentation rate (ESR), C reactive protein (CRP), the Birmingham Vasculitis Activity Score (BVAS), ANCA, organ involvement, and outcomes were analyzed for 152 AAV patients hospitalized in the Second Affiliated Hospital of Chongqing Medical University. Meanwhile, the serum SOD levels of 150 healthy people were collected as the control group.

RESULTS

Compared to the healthy control group, serum SOD levels of the AAV group were significantly lower (P < 0.001). SOD levels of AAV patients were negatively correlated to ESR, CRP, and BVAS (ESR rho = - 0.367, P < 0.001; CRP rho = - 0.590, P < 0.001; BVAS rho = - 0.488, P < 0.001). SOD levels for the MPO-ANCA group were significantly lower than the PR3-ANCA group (P = 0.045). SOD levels for the pulmonary involvement group and the renal involvement group were significantly lower than those for the non-pulmonary involvement group and the non-renal involvement group (P = 0.006; P < 0.001, respectively). SOD levels in the death group were significantly lower than the survival group (P = 0.001).

CONCLUSIONS

In AAV patients, low SOD levels might indicate disease associated oxidative stress. SOD levels in AAV patients were decreased with inflammation, suggesting that SOD levels could potentially be a surrogate marker for disease activity. SOD levels in AAV patients were closely related to ANCA serology, pulmonary involvement, and renal involvement, with low SOD levels an important indicator of a poor prognosis for AAV patients.

Anti-Inflammatory and Antioxidant Properties of Squalene in Copper Sulfate-Induced Inflammation in Zebrafish (Danio rerio)

Long-term or excessive oxidative stress can cause serious damage to fish. Squalene can be added to feed as an antioxidant to improve the body constitution of fish. In this study, the antioxidant activity was detected by 2,2-diphenyl-1-acrylhydrazyl (DPPH) test and fluorescent probe (dichloro-dihydro-fluorescein diacetate). Transgenic Tg (lyz: DsRed2) zebrafish were used to evaluate the effect of squalene on CuSO₄-induced inflammatory response. Quantitative real-time reverse transcription polymerase chain reaction was used to examine the expression of immune-related genes. The DPPH assay demonstrated that the highest free radical scavenging exerted by squalene was 32%. The fluorescence intensity of reactive oxygen species (ROS) decreased significantly after 0.7% or 1% squalene treatment, and squalene could exert an antioxidative effect in vivo. The number of migratory neutrophils in vivo was significantly reduced after treatment with different doses of squalene. Moreover, compared with CuSO₄ treatment alone, treatment with 1% squalene upregulated the expression of sod by 2.5-foldand gpx4b by 1.3-fold to protect zebrafish larvae against CuSO₄-induced oxidative damage. Moreover, treatment with 1% squalene significantly downregulated the expression of tnfa and cox2. This study showed that squalene has potential as an aquafeed additive to provide both anti-inflammatory and antioxidative properties.

The 4-Hydroxynonenal–Protein Adducts and Their Biological Relevance: Are Some Proteins Preferred Targets?

It is well known that oxidative stress and lipid peroxidation (LPO) play a role in physiology and pathology. The most studied LPO product with pleiotropic capabilities is 4-hydroxynonenal (4-HNE). It is considered as an important mediator of cellular signaling processes and a second messenger of reactive oxygen species. The effects of 4-HNE are mainly attributed to its adduction with proteins. Whereas the Michael adducts thus formed are preferred in an order of potency of cysteine > histidine > lysine over Schiff base formation, it is not known which proteins are the preferred targets for 4-HNE under what physiological or pathological conditions. In this review, we briefly discuss the methods used to identify 4-HNE–protein adducts, the progress of mass spectrometry in deciphering the specific protein targets, and their biological relevance, focusing on the role of 4-HNE protein adducts in the adaptive response through modulation of the NRF2/KEAP1 pathway and ferroptosis.

Expression of Nrf2 protein in serum of patients with rheumatoid arthritis: A novel indicator for disease activity and disease prognosis

OBJECTIVE

This study aimed to detect the expression level of nuclear factor erythroid 2-related factor 2 (Nrf2) in the serum of patients with rheumatoid arthritis (RA) to clarify the correlation between Nrf2 levels and medical parameters, such as disease activity, pro-inflammatory factor, clinical characteristics, as well as changes after treatment.

METHODS

Serum samples were collected from 100 patients with RA and 42 normal controls (NCs). Serum levels of Nrf2 protein, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-17A, and malondialdehyde (MDA) were analyzed. The receiver operating characteristic (ROC) curve was adopted to assess the potential of Nrf2 to predict different levels of disease activity in patients with RA. The relationship between clinical variables and parameters were evaluated.

RESULTS

For the first time, it was reported that Nrf2 levels were significantly elevated in the serum of patients with RA compared to those of NCs, as were the MDA levels. The levels of Nrf2 were positively correlated with the disease activity and pro-inflammatory factor levels. The significant cut-off points for Nrf2 to determine RA disease activity were 0.69 ng/mL, 0.69 ng/mL and 1.18 ng/mL. Levels of Nrf2 were higher in RA patients with wrist joint involvement and interstitial lung disease. Moreover, Nrf2 levels decreased after treatment.

CONCLUSIONS

Serum Nrf2 protein level is potentially a novel indicator to monitor disease activity and prognosis in patients with RA.

Discussion on the common controversies of Helicobacter pylori infection

BACKGROUND

Helicobacter pylori ( H. pylori ) can persistently colonize on the gastric mucosa after infection and cause gastritis, atrophy, metaplasia, and even gastric cancer (GC).

METHODS

Therefore, the detection and eradication of H. pylori are the prerequisite.

RESULTS

Clinically, there are some controversial issues, such as why H. pylori infection is persistent, why it translocases along with the lesser curvature of the stomach, why there is oxyntic antralization, what the immunological characteristic of gastric chronic inflammation caused by H. pylori is, whether H. pylori infection is associated with extra-gastric diseases, whether chronic atrophic gastritis (CAG) is reversible, and what the potential problems are after H. pylori eradication. What are the possible answers?

CONCLUSION

In the review, we will discuss these issues from the attachment to eradication in detail.

The role of oxidative stress in the pathogenesis of infections with coronaviruses

Coronaviruses can cause serious respiratory tract infections and may also impact other end organs such as the central nervous system, the lung and the heart. The coronavirus disease 2019 (COVID-19) has had a devastating impact on humanity. Understanding the mechanisms that contribute to the pathogenesis of coronavirus infections, will set the foundation for development of new treatments to attenuate the impact of infections with coronaviruses on host cells and tissues. During infection of host cells, coronaviruses trigger an imbalance between increased production of reactive oxygen species (ROS) and reduced antioxidant host responses that leads to increased redox stress. Subsequently, increased redox stress contributes to reduced antiviral host responses and increased virus-induced inflammation and apoptosis that ultimately drive cell and tissue damage and end organ disease. However, there is limited understanding how different coronaviruses including SARS-CoV-2, manipulate cellular machinery that drives redox responses. This review aims to elucidate the redox mechanisms involved in the replication of coronaviruses and associated inflammation, apoptotic pathways, autoimmunity, vascular dysfunction and tissue damage that collectively contribute to multiorgan damage.

The position of geochemical variables as causal co-factors of diseases of unknown aetiology

Abstract

The term diseases of unknown aetiology (DUA) or idiopathic diseases is used to describe diseases that are of uncertain or unknown cause or origin. Among plausible geoenvironmental co-factors in causation of DUA, this article focusses on the entry of trace elements, including metals and metalloids into humans, and their involvement in humoral and cellular immune responses, representing potentially toxic agents with implications as co-factors for certain DUA. Several trace elements/metals/metalloids (micronutrients) play vital roles as co-factors for essential enzymes and antioxidant molecules, thus, conferring protection against disease. However, inborn errors of trace element/metal/metalloid metabolisms can occur to produce toxicity, such as when there are basic defects in the element transport mechanism. Ultimately, it is the amount of trace element, metal or metalloid that is taken up, its mode of accumulation in human tissues, and related geomedical attributes such as the chemical form and bioavailability that decisively determine whether the exerted effects are toxic or beneficial. Several case descriptions of DUA that are common worldwide are given to illustrate our knowledge so far of how trace element/metal/metalloid interactions in the immune system may engender its dysregulation and be implicated as causal co-factors of DUA.

Article highlights

The importance of a proper understanding of geochemical perturbations in human metabolisms is emphasisedIt is proferred that such an understanding would aid greatly in the decipherment of diseases of unknown aetiology (DUA)The thesis presented may pave the way towards better diagnosis and therapy of DUA.

Assessment of free radicals and reactive oxygen species milieu in nanoparticles adjuvanted outer membrane proteins vaccine against Salmonella typhi

In this study, calcium phosphate nanoparticles-based (STCNV) and montanide oil adjuvant vaccine (STOAV) containing outer membrane proteins (Omps) of S. Typhi were evaluated for inducing oxidative stress indicators [reduced glutathione (GSH), lipid peroxidation (LPO), catalase, superoxide dismutase (SOD), and total protein] in the tissues of mice after vaccination. The GSH levels though slightly high in the liver, kidney, and lungs of STCNV group were not significantly different from STOAV and the control group (STC). There was no significant difference in LPO levels in any group for any tissue. The significantly lower activities of catalase were observed in the kidney and lungs of the STCNV group as compared to STOAV and STC group, while in the liver, STCNV group revealed lower catalase activity in comparison to the control group. No significant difference in the SOD activities between the two vaccinated groups was observed. The total protein contents in all the organs showed no significant difference in the vaccinated and the control group. The vaccines may induce long-term inflammatory response and consequently damage vital organs; this study revealed no long-term oxidative stress in all the three vital organs, suggesting that these vaccines may not cause oxidative damages in the vital organs of mice.

A Comprehensive Overview of the Complex Role of Oxidative Stress in Aging, The Contributing Environmental Stressors and Emerging Antioxidant Therapeutic Interventions

Introduction

Aging is a normal, inevitable, irreversible, and progressive process which is driven by internal and external factors. Oxidative stress, that is the imbalance between prooxidant and antioxidant molecules favoring the first, plays a key role in the pathophysiology of aging and comprises one of the molecular mechanisms underlying age-related diseases. However, the oxidative stress theory of aging has not been successfully proven in all animal models studying lifespan, meaning that altering oxidative stress/antioxidant defense systems did not always lead to a prolonged lifespan, as expected. On the other hand, animal models of age-related pathological phenotypes showed a well-correlated relationship with the levels of prooxidant molecules. Therefore, it seems that oxidative stress plays a more complicated role than the one once believed and this role might be affected by the environment of each organism. Environmental factors such as UV radiation, air pollution, and an unbalanced diet, have also been implicated in the pathophysiology of aging and seem to initiate this process more rapidly and even at younger ages.

Aim

The purpose of this review is to elucidate the role of oxidative stress in the physiology of aging and the effect of certain environmental factors in initiating and sustaining this process. Understanding the pathophysiology of aging will contribute to the development of strategies to postpone this phenomenon. In addition, recent studies investigating ways to alter the antioxidant defense mechanisms in order to prevent aging will be presented.

Conclusions

Careful exposure to harmful environmental factors and the use of antioxidant supplements could potentially affect the biological processes driving aging and slow down the development of age-related diseases. Maybe a prolonged lifespan could not be achieved by this strategy alone, but a longer healthspan could also be a favorable target.

Abrogating Oxidative Stress as a Therapeutic Strategy against Parkinson’s Disease: A Mini Review of the Recent Advances on Natural Therapeutic Antioxidant and Neuroprotective Agents

Background:

Reactive oxygen species (ROS) play a vital role in cell signaling when maintained at low concentrations. However, when ROS production exceeds the neutralizing capacity of endogenous antioxidants, oxidative stress is observed, which has been shown to contribute to neurodegenerative diseases such as Parkinson's disease (PD). PD is a progressive disorder characterized by the loss of dopaminergic neurons from the striatum, which leads to motor and nonmotor symptoms. Although the complex interplay of mechanisms responsible are yet to be fully understood, oxidative stress was found to be positively associated with PD. Despite active research, currently proposed regimens mainly focus on regulating dopamine metabolism within the brain, even though these treatments have shown limited long-term efficacy and several side effects. Due to the implication of oxidative stress in the pathophysiology of PD, natural antioxidant compounds have attracted interest as potential therapeutics over the last years, with a more favorable anticipated safety profile due to their natural origin. Therefore, natural antioxidants are currently being explored as promising anti-PD agents.

Objective:

In this mini review, emphasis was given to presently studied natural antioxidant and neuroprotective agents that have shown positive results in PD animal models.

Methods:

For this purpose, recent scientific articles were reviewed and discussed, with the aim to highlight the most up-to-date advances on PD treatment strategies related to oxidative stress.

Results:

A plethora of natural compounds are actively being explored against PD, including kaemferol, icaritin, artemisinin, and α-bisabolol, with promising results. Most of these compounds have shown adequate neuroprotective ability along with redox balance restoration, normalized mitochondrial function and limitation of the oxidative damage.

Conclusion:

In conclusion, natural antioxidants may be the way forward to novel treatments against PD, when the limitations of correct dosing and appropriate combinations are resolved.

Redox Control of Integrin-Mediated Hepatic Inflammation in Systemic Autoimmunity

Significance: Systemic autoimmunity affects 3%-5% of the population worldwide. Systemic lupus erythematosus (SLE) is a prototypical form of such condition, which affects 20-150 of 100,000 people globally. Liver dysfunction, defined by increased immune cell infiltration into the hepatic parenchyma, is an understudied manifestation that affects up to 20% of SLE patients. Autoimmunity in SLE involves proinflammatory lineage specification in the immune system that occurs with oxidative stress and profound changes in cellular metabolism. As the primary metabolic organ of the body, the liver is uniquely capable to encounter oxidative stress through first-pass derivatization and filtering of waste products. Recent Advances: The traffic of immune cells from their development through recirculation in the liver is guided by cell adhesion molecules (CAMs) and integrins, cell surface proteins that tightly anchor cells together. The surface expression of CAMs and integrins is regulated via endocytic traffic that is sensitive to oxidative stress. Reactive oxygen species (ROS) that elicit oxidative stress in the liver may originate from the mitochondria, the cytosol, or the cell membrane. Critical Issues: While hepatic ROS production is a source of vulnerability, it also modulates the development and function of the immune system. In turn, the liver employs antioxidant defense mechanisms to protect itself from damage that can be harnessed to serve as therapeutic mechanisms against autoimmunity, inflammation, and development of hepatocellular carcinoma. Future Directions: This review is aimed at delineating redox control of integrin signaling in the liver and checkpoints of regulatory impact that can be targeted for treatment of inflammation in systemic autoimmunity. Antioxid. Redox Signal. 36, 367-388.

Diet and Hygiene in Modulating Autoimmunity During the Pandemic Era

The immune system is an efficiently toned machinery that discriminates between friends and foes for achieving both host defense and homeostasis. Deviation of immune recognition from foreign to self and/or long-lasting inflammatory responses results in the breakdown of tolerance. Meanwhile, educating the immune system and developing immunological memory are crucial for mounting defensive immune responses while protecting against autoimmunity. Still to elucidate is how diverse environmental factors could shape autoimmunity. The emergence of a world pandemic such as SARS-CoV-2 (COVID-19) not only threatens the more vulnerable individuals including those with autoimmune conditions but also promotes an unprecedented shift in people's dietary approaches while urging for extraordinary hygiene measures that likely contribute to the development or exacerbation of autoimmunity. Thus, there is an urgent need to understand how environmental factors modulate systemic autoimmunity to better mitigate the incidence and or severity of COVID-19 among the more vulnerable populations. Here, we discuss the effects of diet (macronutrients and micronutrients) and hygiene (the use of disinfectants) on autoimmunity with a focus on systemic lupus erythematosus.

Carbohydrate and lipid metabolism in multiple sclerosis: Clinical implications for etiology, pathogenesis, diagnosis, prognosis, and therapy

Multiple sclerosis (MS) is a complicated autoimmune disease characterized by inflammatory and demyelinating events in the central nervous system. The exact etiology and pathogenesis of MS have not been elucidated. However, a set of metabolic changes and their effects on immune cells and neural functions have been explained. This review highlights the contribution of carbohydrates and lipids metabolism to the etiology and pathogenesis of MS. Then, we have proposed a hypothetical relationship between such metabolic changes and the immune system in patients with MS. Finally, the potential clinical implications of these metabolic changes in diagnosis, prognosis, and discovering therapeutic targets have been discussed. It is concluded that research on the pathophysiological alterations of carbohydrate and lipid metabolism may be a potential strategy for paving the way toward MS treatment.

DNA damage in leukocytes and serum nitrite concentration are negatively associated in type 1 diabetes

Chronic hyperglycaemia leads to DNA damage in diabetes and might be associated with nitrosative stress. In this study, we aimed at assessing the level of DNA strand breaks in leukocytes, serum nitrite and nitrate in patients with type 1 diabetes and healthy controls and associations of these parameters with diabetes-related outcomes in a prospective study. The level of DNA damage was determined in 71 patients with type 1 diabetes and 57 healthy controls by comet assay and scored with arbitrary units (AU). The chemiluminescence method was used to measure nitrite and nitrate. Clinical information and data on consumption of alcohol, physical activity and smoking were collected. Progression of complications in patients with diabetes was assessed after a follow-up time of 4-5 years. We observed a higher level of DNA damage in leukocytes of patients with type 1 diabetes compared with healthy subjects [type 1 diabetes AU 50 (36-74.5); control AU 30 (24.1-43), P < 0.001]. According to regression, type 1 diabetes leads to a 2-fold increase in DNA damage. In the group of type 1 diabetes, DNA damage correlated positively with total cholesterol (R = 0.262, P = 0.028) and negatively with serum glucose level (R = -0.284; P = 0.018) and serum nitrite (R = -0.335; P = 0.008). DNA damage was not significantly associated with HbA1c, diabetes duration, complications and lifestyle factors. However, DNA damage > 57 AU was associated with statistically significantly lower serum nitrite and 1.52 higher risk of progression of complications of diabetes over the follow-up period. The latter result was not statistically significant due to insufficient study power [relative risk 1.52 (95% confidence interval = 0.68, 3.42, P = 0.31)]. Our results confirm that type 1 diabetes is associated with a higher level of DNA strand breaks in leukocytes when compared with the reference group and demonstrate the negative association between DNA damage and serum nitrite concentration.

Protective Role of Natural and Semi-Synthetic Tocopherols on TNFα-Induced ROS Production and ICAM-1 and Cl-2 Expression in HT29 Intestinal Epithelial Cells

Vitamin E, a fat-soluble compound, possesses both antioxidant and non-antioxidant properties. In this study we evaluated, in intestinal HT29 cells, the role of natural tocopherols, α-Toc and δ-Toc, and two semi-synthetic derivatives, namely bis-δ-Toc sulfide (δ-Toc)₂S and bis-δ-Toc disulfide (δ-Toc)₂S₂, on TNFα-induced oxidative stress, and intercellular adhesion molecule-1 (ICAM-1) and claudin-2 (Cl-2) expression. The role of tocopherols was compared to that of N-acetylcysteine (NAC), an antioxidant precursor of glutathione synthesis. The results show that all tocopherol containing derivatives used, prevented TNFα-induced oxidative stress and the increase of ICAM-1 and Cl-2 expression, and that (δ-Toc)₂S and (δ-Toc)₂S₂ are more effective than δ-Toc and α-Toc. The beneficial effects demonstrated were due to tocopherol antioxidant properties, but suppression of TNFα-induced Cl-2 expression seems not only to be related with antioxidant ability. Indeed, while ICAM-1 expression is strongly related to the intracellular redox state, Cl-2 expression is TNFα-up-regulated by both redox and non-redox dependent mechanisms. Since ICAM-1 and Cl-2 increase intestinal bowel diseases, and cause excessive recruitment of immune cells and alteration of the intestinal barrier, natural and, above all, semi-synthetic tocopherols may have a potential role as a therapeutic support against intestinal chronic inflammation, in which TNFα represents an important proinflammatory mediator.

Thymoquinone in autoimmune diseases: Therapeutic potential and molecular mechanisms

Autoimmune diseases (AUDs) are a multifactorial disease, among which rheumatoid arthritis, systemic lupus erythematosus and multiple sclerosis are more prevalent. Several anti-inflammatory, biologics, and AUD-modifying drugs are found effective against them, but their repeated use are associated with various adverse effects. In this review article, we have focused on the regulation of inflammatory molecules, molecular signaling pathways, immune cells, and epigenetics by natural product thymoquinone on AUDs. Studies indicate that thymoquinone can regulate inflammatory molecules including interferons, interleukins, tumor necrosis factor-α (TNF-α), oxidative stress, regulatory T cells, and various signaling pathways such as nuclear factor kappa beta (NF-κβ), janus kinase/signal transduction and activator of transcription (JAK-STAT), mitogen-activated protein kinase (MAPK) at the molecular level and epigenetic alteration. As these molecules and signaling pathways with defective immune function play an important role in AUD development, controlling these molecules and deregulated molecular mechanism is a significant feature of AUD therapeutics. Interestingly thymoquinone is reported to possess all these potential. This article reviewed the deregulated mechanism of AUDs, and the action of thymoquinone on inflammatory molecules, immune cells, signaling pathways, and epigenetic machinery. Thymoquinone can be regarded as a potential drug candidate for AUD treatment.

Efficacy of a web application for stress management among Iranian college students during COVID-19 outbreak: a study protocol for randomized controlled trials

BACKGROUND

The prevalence of mental health disorders is increasing globally, and the prevalence of COVID-19 has made it worse. Evidence has indicated a major mental health burden and elevated anxiety associated with the new coronavirus outbreak in the general population. This study aims to evaluate an evidence-based web application (Naranj) for stress management among Iranian college students.

METHODS AND DESIGN

This study aims to present a protocol related to a randomized controlled trial among Iranian college students. The study will be conducted on 100 students from two colleges of Shiraz University of Medical Sciences in Iran. The participants will be randomly assigned to the intervention and control groups. The intervention group participants will be provided with a web application, whereas the control group ones will be provided with an app unrelated to stress management. The primary outcome for this study will be the Perceived Stress Scale, and the two groups will be compared with respect to stress level and sleep quality.

DISCUSSION

A web application will be developed according to psychological theories and will be scientifically approved for managing college students' stress and improving their sleep quality during the COVID-19 outbreak.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials IRCT20160427027647N2 . Registered on 14 May 2020.

Single-nucleotide polymorphisms (SNPs) of antioxidant enzymes SOD2 and GSTP1 genes and SLE risk and severity in an Egyptian pediatric population

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease associated with increased oxidative stress that participates in immune dysregulation, and injury resulting in loss of immune tolerance and increased auto-antibody production. This study was designed to investigate the effects of genetic polymorphisms of the antioxidant enzymes genes that code for SOD2 (rs2758332) and GSTP1 (rs1695) on SLE risk and severity in Egyptian children and adolescents cohort from Delta region.

METHODS

The frequencies of these genes polymorphic variants were compared between 100 SLE children and adolescents and 100 healthy control subjects. Single-nucleotide polymorphisms (SNPs) of the two antioxidants were determined using TaqMan SNP genotyping assay.

RESULTS

Individuals with the TT and CT genotypes of rs2758332 in the SOD2 gene were of significant risk for SLE patients (OR = 1.831, 95% CI = 1.082-3.101, P = 0.024) and (OR = 1.864, 95% CI = 1.136-3.059, P = 0.014), respectively. Cases who have combined CT + TT genotype were of significant higher risk of SLE (OR = 1.851, 95% CI = 1.156 - 2.962, P = 0.010). While, they did not show any significant association between SOD2 genotypes or alleles with SLE clinical features. In case of the SNP rs1695 in the GSTP1 gene, no significant associations of genotypes or alleles with SLE risk or with SLE clinical features were detected.

CONCLUSIONS

This study among Egyptian children and adolescents showed a strong association of the SOD2 rs2758332 not GSTP1 rs1695 polymorphism with the risk of SLE disease.

KEAP1, a cysteine-based sensor and a drug target for the prevention and treatment of chronic disease

Redox imbalance and persistent inflammation are the underlying causes of most chronic diseases. Mammalian cells have evolved elaborate mechanisms for restoring redox homeostasis and resolving acute inflammatory responses. One prominent mechanism is that of inducing the expression of antioxidant, anti-inflammatory and other cytoprotective proteins, while also suppressing the production of pro-inflammatory mediators, through the activation of transcription factor nuclear factor-erythroid 2 p45-related factor 2 (NRF2). At homeostatic conditions, NRF2 is a short-lived protein, which avidly binds to Kelch-like ECH-associated protein 1 (KEAP1). KEAP1 functions as (i) a substrate adaptor for a Cullin 3 (CUL3)-based E3 ubiquitin ligase that targets NRF2 for ubiquitination and proteasomal degradation, and (ii) a cysteine-based sensor for a myriad of physiological and pharmacological NRF2 activators. Here, we review the intricate molecular mechanisms by which KEAP1 senses electrophiles and oxidants. Chemical modification of specific cysteine sensors of KEAP1 results in loss of NRF2-repressor function and alterations in the expression of NRF2-target genes that encode large networks of diverse proteins, which collectively restore redox balance and resolve inflammation, thus ensuring a comprehensive cytoprotection. We focus on the cyclic cyanoenones, the most potent NRF2 activators, some of which are currently in clinical trials for various pathologies characterized by redox imbalance and inflammation.