Status of oxidative stress in rheumatoid arthritis

Low Levels of IgM Recognizing 4-Hydroxy-2-Nonenal-Modified Apolipoprotein A-I Peptide and Its Association with the Severity of Coronary Artery Disease in Taiwanese Patients

Autoantibodies against apolipoprotein A-I (ApoA-I) are associated with cardiovascular disease risks. We aimed to examine the 4-hydroxy-2-nonenal (HNE) modification of ApoA-I in coronary artery disease (CAD) and evaluate the potential risk of autoantibodies against their unmodified and HNE-modified peptides. We assessed plasma levels of ApoA-I, HNE-protein adducts, and autoantibodies against unmodified and HNE-peptide adducts, and significant correlations and odds ratios (ORs) were examined. Two novel CAD-specific HNE-peptide adducts, ApoA-I251-262 and ApoA-I70-83, were identified. Notably, immunoglobulin G (IgG) anti-ApoA-I251-262 HNE, IgM anti-ApoA-I70-83 HNE, IgG anti-ApoA-I251-262, IgG anti-ApoA-I70-83, and HNE-protein adducts were significantly correlated with triglycerides, creatinine, or high-density lipoprotein in CAD with various degrees of stenosis (<30% or >70%). The HNE-protein adduct (OR = 2.208-fold, p = 0.020) and IgM anti-ApoA-I251-262 HNE (2.046-fold, p = 0.035) showed an increased risk of progression from >30% stenosis in CAD. HNE-protein adducts and IgM anti-ApoA-I251-262 HNE may increase the severity of CAD at high and low levels, respectively.

A Nanomedicine-Enabled Ion-Exchange Strategy for Enhancing Curcumin-Based Rheumatoid Arthritis Therapy

Curcumin (Cur) has been clinically used for rheumatoid arthritis treatment by the means of reactive oxygen species (ROS) scavenging and immune microenvironment regulation. However, this compound has a poor water solubility and moderate antioxidative activity, favoring no further broadened application. Metal complexes of curcumin such as zinc-curcumin (Zn-Cur) features enhanced water solubilities, while copper-curcumin (Cu-Cur) shows a higher antioxidant activity but lower solubility than Zn-Cur. Based on their inherent biological properties, this work proposes a nanomedicine-based ion-exchange strategy to enhance the efficacy of Cur for rheumatoid arthritis treatment. Copper silicate nanoparticles with hollow mesoporous structure were prepared to load water-soluble Zn-Cur for constructing a composite nanomedicine, which can degrade in acidic microenvironment of arthritic region, releasing Cu2+ and Zn-Cur. Cu2+ then substitute for Zn2+ in Zn-Cur to form Cu-Cur with a significantly enhanced antioxidative effect, capable of efficiently scavenging ROS in M1 macrophages, promoting their transition to an anti-inflammatory M2 phenotype. In addition, the silicate released after nanocarrier degradation and the Zn2+ released after ion exchange reaction synergistically promote the biomineralization of osteoblasts. This work provides a new approach for enhancing the antiarthritic effect of Cur via an ion-exchange strategy.

The Synergy between Glutathione and Phenols-Phenolic Antioxidants Repair Glutathione: Closing the Virtuous Circle-A Theoretical Insight

Glutathione (GSH) and phenols are well-known antioxidants, and previous research has suggested that their combination can enhance antioxidant activity. In this study, we used Quantum Chemistry and computational kinetics to investigate how this synergy occurs and elucidate the underlying reaction mechanisms. Our results showed that phenolic antioxidants could repair GSH through sequential proton loss electron transfer (SPLET) in aqueous media, with rate constants ranging from 3.21 × 10⁶ M^-1 s^-1 for catechol to 6.65 × 10⁸ M^-1 s^-1 for piceatannol, and through proton-coupled electron transfer (PCET) in lipid media with rate constants ranging from 8.64 × 10⁶ M^-1 s^-1 for catechol to 5.53 × 10⁷ M^-1 s^-1 for piceatannol. Previously it was found that superoxide radical anion (O₂^•-) can repair phenols, thereby completing the synergistic circle. These findings shed light on the mechanism underlying the beneficial effects of combining GSH and phenols as antioxidants.

Long Term Treatment of Corticostreroids May Cause Hepatotoxicity and Oxidative Damage: A Case Controlled Study

Arthritis is a clinical condition, which mainly affects the structure and function joints. During this condition the joints gets swelled and stiffed resulting into development of pain and morbidity. Corticosteroids are frequently prescribed to manage various clinical conditions including the chronic inflammatory diseases such as arthritis. The steroidal drug also causes certain adverse effects depending on the dose, the route of administration and duration of treatment. However, a systematic investigation on the biochemical consequences of steroids as a therapeutic has not been carried out. In the present study we analyzed certain parameters associated to oxidative stress, liver function and energy metabolism has been done in the blood plasma of the arthritis patients who were using steroidal drugs (methylprednisolone and deflazacort) up to 168 days for the treatment of the disease. The results indicated increase in level of MDA and decrease in the activities of SOD, CAT and LDH. The activities of AST and ALT were found to be significantly enhanced over the increase in the treatment period. These results suggested that corticosteroids may induce lipid peroxidation, oxidative stress and liver toxicity in the arthritis patients in the dose and duration dependent manner. The use of antioxidants as supplements to the anti-arthritis agents could play a role in suppressing the oxidative stress mediated adverse effects. However, extensive research is required to explore for safer medication devoid of steroids to cure arthritis.

Graphical Abstract

Edible Seaweeds Extracts: Characterization and Functional Properties for Health Conditions

Seaweeds are popular foods due to claimed beneficial health effects, but for many there is a lack of scientific evidence. In this study, extracts of the edible seaweeds Aramé, Nori, and Fucus are compared. Our approach intends to clarify similarities and differences in the health properties of these seaweeds, thus contributing to target potential applications for each. Additionally, although Aramé and Fucus seaweeds are highly explored, information on Nori composition and bioactivities is scarce. The aqueous extracts of the seaweeds were obtained by decoction, then fractionated and characterized according to their composition and biological activity. It was recognized that fractioning the extracts led to bioactivity reduction, suggesting a loss of bioactive compounds synergies. The Aramé extract showed the highest antioxidant activity and Nori exhibited the highest potential for acetylcholinesterase inhibition. The identification of the bioactive compounds in the extracts allowed to see that these contained a mixture of phloroglucinol polymers, and it was suggested that Nori’s effect on acetylcholinesterase inhibition may be associated with a smaller sized phlorotannins capable of entering the enzyme active site. Overall, these results suggest a promising potential for the use of these seaweed extracts, mainly Aramé and Nori, in health improvement and management of diseases, namely those associated to oxidative stress and neurodegeneration.

Free Radicals and Oxidative Stress: Signaling Mechanisms, Redox Basis for Human Diseases, and Cell Cycle Regulation

Free radicals contain one or more unpaired electrons in their valence shell, thus making them unstable, short-lived, and highly reactive species. Excessive generation of these free radicals ultimately leads to oxidative stress causing oxidation and damage to significant macromolecules in the living system and essentially disrupting signal transduction pathways and antioxidants equilibrium. At lower concentrations, ROS serves as "second messengers," influencing many physiological processes in the cell. However, higher concentrations beyond cell capacity cause oxidative stress, contributing to human pathologies such as diabetes, cancer, Parkinson's disease, cardiovascular diseases, cataract, asthma, hypertension, atherosclerosis, arthritis, and Alzheimer's disease. Signaling pathways such as NF-κB, MAPKs, PI3K/Akt/ mTOR, and Keap1-Nrf2- ARE modulate the detrimental effects of oxidative stress by increasing the expression of cellular antioxidant defenses, phase II detoxification enzymes, and decreased production of ROS. Free radicals such as H2O2 are indeed needed for the advancement of the cell cycle as these molecules influence DNA, proteins, and enzymes in the cell cycle pathway. In the course of cell cycle progression, the cellular redox environment becomes more oxidized, moving from the G1 phase, becoming higher in G2/M and moderate in the S phase. Signals in the form of an increase in cellular pro-oxidant levels are required, and these signals are often terminated by a rise in the amount of antioxidants and MnSOD with a decrease in the level of cyclin D1 proteins. Therefore, understanding the mechanism of cell cycle redox regulation will help in the therapy of many diseases.

Nanoenzyme engineered neutrophil-derived exosomes attenuate joint injury in advanced rheumatoid arthritis via regulating inflammatory environment

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovitis and destruction of cartilage, promoted by sustained inflammation. However, current treatments remain unsatisfactory due to lacking of selective and effective strategies for alleviating inflammatory environments in RA joint. Inspired by neutrophil chemotaxis for inflammatory region, we therefore developed neutrophil-derived exosomes functionalized with sub-5 nm ultrasmall Prussian blue nanoparticles (uPB-Exo) via click chemistry, inheriting neutrophil-targeted biological molecules and owning excellent anti-inflammatory properties. uPB-Exo can selectively accumulate in activated fibroblast-like synoviocytes, subsequently neutralizing pro-inflammatory factors, scavenging reactive oxygen species, and alleviating inflammatory stress. In addition, uPB-Exo effectively targeted to inflammatory synovitis, penetrated deeply into the cartilage and real-time visualized inflamed joint through MRI system, leading to precise diagnosis of RA in vivo with high sensitivity and specificity. Particularly, uPB-Exo induced a cascade of anti-inflammatory events via Th17/Treg cell balance regulation, thereby significantly ameliorating joint damage. Therefore, nanoenzyme functionalized exosomes hold the great potential for enhanced treatment of RA in clinic.

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uPB-Exo were firstly developed by combining NE-Exo with sub-5 nm ultrasmall PB nanoparticles via click chemistry.

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uPB-Exo selectively targeted inflamed joints via neutrophil-targeted biological molecules inherited from neutrophils.

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uPB-Exo accumulated in active FLS, and eventually scavenged reactive oxygen species and alleviated inflammatory stress.

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uPB-Exo induced a cascade of anti-inflammatory events via Th17/Treg cell balance regulation, thereby significantly ameliorating joint damage.

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uPB-Exo, as a drug free therapeutical agent, holds the great potential for enhanced treatment of RA in clinic.

Targeting Oxidative Stress Involved in Endometriosis and Its Pain

Endometriosis is a common gynecological disorder seen in women and is characterized by chronic pelvic pain and infertility. This disorder is becoming more prevalent with increased morbidity. The etiology of endometriosis remains to be fully elucidated, which will lead to improved therapeutic options. In this review, we will evaluate the biochemical mechanisms leading to oxidative stress and their implication in the pathophysiology of endometriosis, as well as potential treatments that target these processes. A comprehensive exploration of previous research revealed that endometriosis is associated with elevated reactive oxygen species and oxidation products, decreased antioxidants and detoxification enzymes, and dysregulated iron metabolism. High levels of oxidative stress contributed to inflammation, extracellular matrix degradation, angiogenesis, and cell proliferation, which may explain its role in endometriosis. Endometriosis-associated pain was attributed to neurogenic inflammation and a feed-forward mechanism involving macrophages, pro-inflammatory cytokines, and pain-inducing prostaglandins. N-acetylcysteine, curcumin, melatonin, and combined vitamin C and E supplementation displayed promising results for the treatment of endometriosis, but further research is needed for their use in this population.

Leveraging whole blood based functional flow cytometry assays to open new perspectives for rheumatoid arthritis translational research

Despite introduction of biological disease modifying anti-rheumatic drugs (DMARDs) for Rheumatoid arthritis (RA) treatment, therapeutic strategies do not always lead to disease control and remission. Hence, a more efficient patient stratification and monitoring biomarkers and tools are needed to enable a more personalized medicine. We used a whole blood based functional flow cytometry assay to characterize immune cells from RA patients (treated or not), healthy donors and psoriatic arthritis (PsA) patients according to their responses to LPS and/or anti-TNFα (infliximab, IFX). Activation marker expression was measured using a 10-color flow cytometry panel following a no-wash protocol. Naïve-to-treatment RA patients had a stronger inflammatory profile in comparison to healthy donors at basal level. Higher expression of activation markers (CD69 and/or CD11b) on NK, B cells and granulocytes and lower expression of the adhesion molecule CD62L were measured on monocytes, granulocytes and B cells. After LPS, naïve RA patients' cells were less capable of regulating CD69, CD11b, CD16 or CD62L showing impaired activation capabilities. Upon LPS and IFX co-incubation, hierarchical clustering analysis showed different profiles between cohorts. We believe that this whole blood-based approach should further be assessed for RA patient characterization as it provides new perspectives for stratification and/or monitoring.

Expression Profile of mRNAs and miRNAs Related to the Oxidative-Stress Phenomenon in the Ishikawa Cell Line Treated Either Cisplatin or Salinomycin

The oxidative stress phenomenon is a result of anticancer therapy. The aim of this study was the assessment of gene expression profile changes, and to determine the miRNAs regulating genes’ transcriptional activity in an Ishikawa endometrial cancer culture exposed to cisplatin or salinomycin, compared to a control culture. The molecular analysis comprised the microarray technique (mRNAs and micro RNA (miRNA), the real-time quantitative reverse transcription reaction (RTqPCR), enzyme-linked immunosorbent assay (ELISA) reactions, and Western blot. NR4A2, MAP3K8, ICAM1, IL21, CXCL8, CCL7, and SLC7A11 were statistically significantly differentiated depending not only on time, but also on the drug used in the experiment. The conducted assessment indicated that the strongest links were between NR4A2 and hsa-miR-30a-5p and has-miR-302e, MAP3K8 and hsa-miR-144-3p, CXCL8 and hsa-miR-140-3p, and SLC7A11 and hsa-miR-144-3p. The obtained results suggest that four mRNAs—NR4A2, MAP3K8, CXCL8 and SLC7A11—and four miRNAs—hsa-miR-30a-5p, hsa-miR-302e, hsa-miR-144-3p and hsa-miR-140-3—changed their expressions regardless of the chemotherapeutic agent used, which suggests the possibility of their use in monitoring the severity of oxidative stress in endometrial cancer. However, considering the results at both the mRNA and the protein level, it is most likely that the expressions of NR4A2, MAP3K8, CXCL8 and SLC7A11 are regulated by miRNA molecules as well as other epigenetic mechanisms.

Evaluation of Antiarthritic and Antinociceptive Effects of Cedrol in a Rat Model of Arthritis

Pharmacological studies revealed that cedrol, a natural sesquiterpene, has antioxidant, anti-inflammatory, and analgesic properties. This study is aimed at evaluating the potential antiarthritic activity of cedrol in a rat experimental model of arthritis induced by using complete Freund's adjuvant (CFA). Arthritis was induced in Wistar rats by CFA (0.1 ml) injection. Cedrol (10 and 20 mg/kg) and indomethacin (5 mg/kg) were orally administered from day one and continued for 21 days. The antiarthritic activity was assessed through mechanical allodynia and thermal hyperalgesia responses, paw edema assessment, and arthritis scores. Serum TNF-α and IL-1β levels were measured for the evaluation of inflammation. Furthermore, serum oxidative stress markers, including malondialdehyde (MDA) and thiol levels, as well as superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities, were also assessed. Oral administration of cedrol and indomethacin significantly decreased paw edema and arthritis score. Besides, cedrol and indomethacin significantly decreased pain responses. In the serum of the CFA group, TNF-α, IL-1β, and MDA were higher, while thiol and SOD and GPx were lower than the control group. Treatment by cedrol and indomethacin corrected the biochemical parameters in the serum. In this study, cedrol offers potential antiarthritic properties through its anti-inflammatory and antioxidant effects.

Pharmacological evaluation of anti-arthritic potential of terpinen-4-ol using in vitro and in vivo assays

Terpinen 4-ol, a phytochemical is a monoterpene which has been reported for its anti-inflammatory effect. Present research was planned to check its effect against arthritis through in vitro and in vivo models. Terpinen 4-ol was evaluated through in-vitro procedures including blocking of protein (BSA and egg albumin) denaturation and human RBC membrane stabilization. In in vivo study, terpinen 4-ol (15, 30 and 60 mg/kg) was evaluated using formaldehyde and CFA arthritic models. Terpinen 4-ol significantly inhibited increase in paw and joint swelling as compared to diseased group. Terpinen 4-ol showed remarkable antioxidant effect (SOD, reducing power) and also improved body weight, haematological, histopathological and radiological parameters in CFA model. Also, moreover, the excess production of IL-1β, TNF-α, IRAK, and NF-kB were noticeably attenuated in all terpinen 4-ol treated rats, however, IL-17 and IL-10 were distinctly increased compared to arthritic control rats in RT-PCR. Also, terpinen 4-ol showed promising antioxidant effect in DPPH assay. Henceforth, it might be concluded that terpinen 4-ol has anti-arthritic effect which can be attributed to the downregulation of pro-inflammatory cytokines.

Chemical repair of damaged leucine and tryptophane by thiophenols at close to diffusion-controlled rates: Mechanisms and kinetics

Thiophenols are chemical species with multiple desirable biological properties, including their primary and secondary antioxidant capacity. In this work, the repairing antioxidant activity of eight different thiophenols has been investigated for damaged leucine and tryptophane. The investigation was carried out employing quantum mechanical and transition state methods to calculate the thermodynamic and kinetic data of the reactions involved, while simulating the biological conditions at physiological pH and aqueous and lipidic medium. The analysis of the atomic charges and the spin densities at each of the points on the potential energy surface was the tool that allowed the elucidation of the reaction mechanisms through which thiophenols repair the oxidative damage caused to the amino acids leucine and tryptophan. It was found that thiophenols can repair leucine via a hydrogen atom transfer mechanism in a manner which is similar to the one used by glutathione to repair the carbon-centered radicals of guanosine. In addition, thiophenols can also restore tryptophane, a nitrogen-centered radical, via proton-coupled electron transfer and single electron transfer mechanisms. Moreover, both processes occur at close to diffusion-controlled rates.

Mechanisms of action of radon therapy on cytokine levels in normal mice and rheumatoid arthritis mouse model

The typical indication of radon therapy is rheumatoid arthritis. Although there are several reports that radon therapy has regulation effects on Th17 cells, there has been no study reporting that radon inhalation affects the immune balance among Th1, Th2, and Th17. The purpose of this study is to examine the cytokine changes after radon inhalation. BALB/c mice inhaled radon at 2,000 Bq/m³ for 2 or 4 weeks. SKG/Jcl mice inhaled radon at 2,000 Bq/m³ for 4 weeks after zymosan administration. The results showed that radon inhalation for 4 weeks activated the immune response of Th1, Th2, and Th17. Moreover, the balance among them was not lost by radon inhalation. Radon inhalation for 4 weeks decreased superoxide dismutase activity and increased catalase activity in spleen. These findings suggest that an imbalance of oxidative stress may contribute to activate the immune response. Although zymosan administration activated Th17 immune response and decreased Th1 and Th2 immune response in SKG/Jcl mice, most cytokines related to Th1, Th2, and Th17 approached the normal level by radon inhalation. These findings suggested that radon inhalation has a different action between SKG/Jcl mice and normal BABL/c mice. This may indicate that radon inhalation has an immunomodulation function.

Alpha-tocopherol-loaded polycaprolactone nanoparticles improve the inflammation and systemic oxidative stress of arthritic rats

Background and aim

The present study investigated the effects of orally administered α-tocopherol-loaded polycaprolactone nanoparticles on the articular inflammation and systemic oxidative status of middle-aged Holtzman rats with Freund's adjuvant-induced polyarthritis, a model for rheumatoid arthritis. Intraperitoneally administered free α-tocopherol provided the reference for comparison.

Experimental procedure

Two protocols of treatment were followed: intraperitoneal administration of free α-tocopherol (100 mg/kg i.p.) or oral administration of free and nanoencapsulated α-tocopherol (100 mg/kg p.o.). Animals were treated during 18 days after arthritis induction.

Results

Free (i.p.) and encapsulated α-tocopherol decreased the hind paws edema, the leukocytes infiltration into femorotibial joints and the mRNA expression of pro-inflammatory cytokines in the tibial anterior muscle of arthritic rats, but the encapsulated compound was more effective. Free (i.p.) and encapsulated α-tocopherol decreased the high levels of reactive oxygen species in the brain and liver, but only the encapsulated compound decreased the levels of protein carbonyl groups in these organs. Both free (i.p.) and encapsulated α-tocopherol increased the α-tocopherol levels and the ratio of reduced to oxidized glutathione in these organs.

Conclusion

Both intraperitoneally administered free α-tocopherol and orally administered encapsulated α-tocopherol effectively improved inflammation and systemic oxidative stress in middle-aged arthritic rats. However, the encapsulated form should be preferred because the oral administration route does not be linked to the evident discomfort that is caused in general by injectable medicaments. Consequently, α-tocopherol-loaded polycaprolactone nanoparticles may be a promising adjuvant to the most current approaches aiming at rheumatoid arthritis therapy.

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Oxidative stress is systemically increased in rats with adjuvant-induced arthritis.

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Arthritic rats were orally treated with α-tocopherol-loaded polycaprolactone nanoparticles.

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Treatment decreased the paw edema and articular inflammation of arthritic rats.

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Treatment improved the oxidative stress in the liver and brain arthritic rats.

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The content of α-tocopherol was increased in the brain and liver of treated rats.

Comparison of individual and combination treatments with naproxen, prednisolone and hydroxychloroquine to treat Complete Freund's Adjuvant induced arthritis

Aim of this study was to evaluate and compare the efficacy of anti-arthritic drugs (naproxen, prednisolone, and hydroxychloroquine) alone and in combination. The in vitro anti-arthritic activity was evaluated by stabilization of human erythrocytes (HRBCs) membrane assays. In vivo activity was carried out using Complete Freund's Adjuvant (CFA) induced arthritic model in Wistar rat. Individual and combination drugs were administered for 21 days in rats 8 days post inoculation with CFA (0.15 ml injected in right hind paw). Body weight and paw edema were measured at different intervals. Combination treatments exhibited more HRBC stabilization than individual treatments. All individual and combination treatments reduced the level of C-reactive protein (CRP), liver function enzymes, malondialdehyde, white blood cells and platelets, with the most pronounced activity exhibited by the combination of three drugs. The level of oxidative stress biomarkers (reduced glutathione, catalase, and superoxide dismutase), red blood cells, and hemoglobin were notably increased in all treatment groups in contrasts to diseased control rats. Histopathological evaluation of the paw showed that all the treatments had reduced (p < 0.05-0.001) the arthritic indices in contrasts to diseased control rats. The serum concentrations of TNF-α and PGE2 were provoked in diseased control rats but had been notably (p < 0.0001) restored by treatments with individual and combination drugs. It was also found that combination treatments, more precisely triple drug was remarkably effective in treating arthritis. It can be concluded that naproxen, prednisolone, and hydroxychloroquine effectively ameliorated the CFA-induced arthritis and were more effective in combination as compared to individual drug therapy probably due to reduction in oxidative stress and inflammatory markers. Moreover, two lower doses (half NPH/2 and one-third NPH/3) of triple combination therapy naproxen, prednisolone, and hydroxychloroquine (NPH) showed no significant difference in anti-arthritic effect as compared to the highest dose level of NPH.

Sinapic Acid Attenuates Rheumatoid Arthritis Through Reducing Inflammation and Oxidative Stress by Downregulating IκB Kinase

Sinapic acid (SA) was reported to protect against inflammation in various types of diseases. However, the role of SA in rheumatoid arthritis remains unclear. This study was designed to investigate the role of SA on rheumatoid arthritis. Rheumatoid arthritis mouse model was established by collagen immunization [collagen-induced arthritis (CIA)]. Histological analysis of articular cartilage tissue was carried out by hematoxylin and eosin (H&E) staining. Serum concentrations of tumor necrosis factor alpha and interleukin 6 were determined through enzyme-linked immunosorbent assay (ELISA). Oxidative damage indexes such as superoxide dismutase activity, malondialdehyde detection, glutathione detection, and catalase were determined by biochemical analysis. The protein levels of related genes were determined using Western blot. In CIA model, SA treatment attenuated paw swelling and clinical score of arthritis, attenuated articular cartilage tissues edema and infiltration of inflammatory cells, suppressed inflammatory cytokines release, and attenuated oxidative damage indexes. Mechanically, SA suppressed immune responses through inhibiting the IκB kinase (IKKs). SA attenuates rheumatoid arthritis through reducing inflammation and oxidative stress by downregulating IKKs.

Redox Status in Women with Rheumathoid Arthritis

The aim of this study was to assess oxidative status and to set baseline characteristics for female population with established rheumatoid arthritis. Total of 42 patients with rheumatoid arthritis and 48 age- and sex-matched controls were included in the study. Clinical examination was performed and assessed disease activity. Peripheral blood samples were used for all the assays. The markers of oxidative stress were assessed, including plasma levels of index of lipid peroxidation – thiobarbituric acid reactive substances, hydrogen peroxide, superoxide anion radical, nitrites and activity of superoxide dismutase, catalase and reduced glutathione levels as anti-oxidant parameters. In the patients group, levels of hydrogen peroxide and index of lipid peroxidation were higher than in controls. Patients with rheumatoid arthritis had decreased su-peroxide dismutase and catalase activity compared to healthy subjects. Interestingly, controls had higher levels of nitrites compared to patients. Patients showed a marked increase in reactive oxygen species formation and lipid peroxidation as well as decrease in the activity of antioxidant defense system leading to oxidative stress which may contribute to tissue and cartilage damage and hence to the chronicity of the disease.

Activation of the Nrf2/HO-1 signaling pathway by dimethyl fumarate ameliorates complete Freund's adjuvant-induced arthritis in rats

The nuclear factor erythroid 2-related factor (Nrf2) signaling pathway has recently emerged as a novel therapeutic target in treating various diseases. Therefore, the present study aimed to assess the protective role of the Nrf2 activator, dimethyl fumarate (DMF) in the complete Freund's adjuvant (CFA)- induced arthritis model. DMF (25, 50, and 100 mg/kg) and dexamethasone (2 mg/kg) were orally administered for 14 days. Pain-related tests, paw volume, and arthritic scores were measured weekly. Serum TNF-α, IL-1β, cyclic citrullinated peptide (CCP), C-reactive protein (CRP), and rheumatoid factor (RF) levels were estimated. Nitrite, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (GSH), catalase (CAT), and myeloperoxidase (MPO) levels were also evaluated. NF-κB, Nrf2, HO-1, and COX-2 levels were estimated in the joint tissue. DMF treatment exerted anti-arthritic activity by enhancing the nociceptive threshold, improving arthritis scores, and reducing paw edema. Also, DMF suppressed changes in oxidative stress markers and inflammatory mediators and enhanced Nrf2 and HO-1 levels in CFA-injected rats. These findings indicate that the anti-arthritic activity of DMF may be mediated by the activation of the Nrf2/HO-1 pathway, which reduced oxidative damage and inflammation.

Alterations of Extracellular Matrix Components in the Course of Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is the most common group of chronic connective tissue diseases in children that is accompanied by joint structure and function disorders. Inflammation underlying the pathogenic changes in JIA, caused by hypersecretion of proinflammatory cytokines, leads to the destruction of articular cartilage. The degradation which progresses with the duration of JIA is not compensated by the extent of repair processes. These disorders are attributed in particular to changes in homeostasis of extracellular matrix (ECM) components, including proteoglycans, that forms articular cartilage. Changes in metabolism of matrix components, associated with the disturbance of their degradation and biosynthesis processes, are the basis of the progressive wear of joint structures observed in the course of JIA. Clinical evaluation and radiographic imaging are current methods to identify the destruction. The aim of this paper is to review enzymatic and non-enzymatic factors involved in catabolism of matrix components and molecules stimulating their biosynthesis. Therefore, we discuss the changes in these factors in body fluids of children with JIA and their potential diagnostic use in the assessment of disease activity. Understanding the changes in ECM components in the course of the child-hood arthritis may provide the introduction of both new diagnostic tools and new therapeutic strategies in children with JIA.

Anti-nociceptive effect of Portulaca oleracea L. ethanol extracts attenuated zymosan-induced mouse joint inflammation via inhibition of Nrf2 expression

The aim of this study was to explore the effects of ethanol extracts from Portulaca oleracea L. (ePO) on joint inflammation and to explain the underlying mechanisms. A joint inflammation mouse model was constructed by injecting zymosan, and the Von Frey method was employed and the joint thickness measured. The numbers of leukocytes, neutrophils, and monocytes were counted in the joint cavity and the infiltration of inflammatory cells was assessed by joint histopathological analysis. The mRNA levels of inflammatory cytokines were determined by quantitative RT-PCR and their secretion levels were determined by specific ELISAs. Pre-treatment with ePO inhibited articular mechanical hyperalgesia and edema and ameliorated the recruitment of mononuclear neutrophils and leukocytes. In addition, pre-treatment with ePO improved pathological alternations in the joint tissues by reducing the number of inflammatory cells. Pre-treatment with ePO regulated the nuclear factor erythroid 2-related factor 2 (Nrf2)-related proteins and thereby inhibited oxidative stress. In addition, ePO inhibited NLR family pyrin domain containing 3 (NLRP3) inflammasome-related genes (NLRP3, ASC, pro-caspase-1 and pro-IL-1ß), modulated inflammatory cytokines and the activation of NF-κB. ePO attenuated zymosan-induced joint inflammation by regulating oxidative stress, NLRP3 inflammasome, and NF-κB.

The Influence of Menopause and Inflammation on Redox Status and Bone Mineral Density in Patients with Rheumatoid Arthritis

Although oxidative stress is considered to be one of the key pathogenic factors in rheumatoid arthritis (RA), there is insufficient knowledge regarding the impact of menopause on redox status in this population. Thus, this study is aimed at assessing the influence of menopause within healthy women and within RA patients as well as the impact of RA in premenopausal and postmenopausal women on redox status, with special reference to bone mineral density (BMD). A total of 90 women were included in the study, 42 with RA and 48 age-matched healthy controls. They were divided into subgroups according to the presence of menopause. Following oxidative stress parameters were measured spectrophotometrically: index of lipid peroxidation (measured as TBARS), nitrites (NO2 -), superoxide anion radical (O2 -), hydrogen peroxide (H2O2), superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH). BMD was assessed by using a dual-energy X-ray absorptiometry scanner. Comorbidities and drug history were recorded. The levels of H2O2 and TBARS were elevated in patients with RA, while NO2 - and O2 - increased in healthy women, both in premenopausal and postmenopausal groups. SOD activity decreased in postmenopausal RA patients. BMD was reduced in postmenopausal RA women. There was a correlation between NO2 - and O2 - with Health Assessment Questionnaire (HAQ) index in RA patients. Given that postmenopausal state was associated with elevated oxidative stress within healthy women and that menopausal state did not affect redox homeostasis within RA patients, but the redox homeostasis was altered in both RA groups compared to healthy women, it can be presumed that impaired redox status in RA occurred due to presence of the disease, irrespective of age. Moreover, menopause attenuates BMD reduction in women with RA. These results may indicate the need for therapeutic use of antioxidants in the form of supplements in women with RA, regardless of age.

1H-NMR-Based Analysis for Exploring Knee Synovial Fluid Metabolite Changes after Local Cryotherapy in Knee Arthritis Patients

Rehabilitation using cryotherapy has widely been used in inflammatory diseases to relieve pain and decrease the disease activity. The aim of this study was to explore the metabolite changes in inflammatory knee-joint synovial fluids following local cryotherapy treatment (ice or cold CO2). We used proton nuclear magnetic resonance (1H NMR) spectroscopy to assess the metabolite patterns in synovial fluid (SF) in patients with knee arthritis (n = 46) before (D0) and after (D1, 24 h later) two applications of local cryotherapy. Spectra from aqueous samples and organic extracts were obtained with an 11.75 Tesla spectrometer. The metabolite concentrations within the SF were compared between D1 and D0 using multiple comparisons with the application of a false discovery rate (FDR) adjusted at 10% for each metabolite. A total of 32 metabolites/chemical structures were identified including amino acids, organic acids, fatty acids or sugars. Pyruvate, alanine, citrate, threonine was significantly higher at D1 vs D0 (p < 0.05). Tyrosine concentration significantly decreases after cryotherapy application (p < 0.001). We did not observe any effect of gender and cooling technique on metabolite concentrations between D0 and D1 (p > 0.05). The present study provides new insight into a short-term effect of cold stimulus in synovial fluid from patients with knee arthritis. Our observations suggest that the increased level of metabolites involved in energy metabolism may explain the underlying molecular pathways that mediate the antioxidant and anti-inflammatory capacities of cryotherapy.

How the redox state regulates immunity

Oxidative stress is defined as an imbalance between the levels of reactive oxygen species (ROS) and antioxidant defences. The view of oxidative stress as a cause of cell damage has evolved over the past few decades to a much more nuanced view of the role of oxidative changes in cell physiology. This is no more evident than in the field of immunity, where oxidative changes are now known to regulate many aspects of the immune response, and inflammatory pathways in particular. Our understanding of redox regulation of immunity now encompasses not only increases in reactive oxygen and nitrogen species, but also changes in the activities of oxidoreductase enzymes. These enzymes are important regulators of immune pathways both via changes in their redox activity, but also via other more recently identified cytokine-like functions. The emerging picture of redox regulation of immune pathways is one of increasing complexity and while therapeutic targeting of the redox environment to treat inflammatory disease is a possibility, any such strategy is likely to be more nuanced than simply inhibiting ROS production.

Accelerated ageing profile in inflammatory arthritis is unique and tissue compartment specific

Rheumatoid arthritis is prevalent in more than 1% of the global population, with the highest occurrence between ages 35 and 50, which places a huge burden on the economy. Drug discovery for the prevention of this chronic disease is; therefore, a priority. It is known that subclinical progression of many chronic non-communicable diseases is exacerbated via accelerated ageing, a pro-inflammatory phenotype shift. However, rheumatoid arthritis additionally has significant humoral immune activation, inflammatory signalling-and thus the accelerated ageing profile-may differ from other chronic inflammatory diseases. The current study simulated inflammatory arthritis onset in a collagen-induced arthritis (CIA) rodent model, to characterise the redox and inflammatory profile at the onset of clinical symptoms, in different tissues, in the presence and absence of preventative antioxidant treatment. The data illustrate that an increased free radical level are evident already very early on in RA disease progression. Furthermore, oxidative stress seems to somewhat precede a significant pro-inflammatory state, perhaps due to humoral immune activation. Our data across different compartments further suggest that the compensatory increase in endogenous antioxidant activity is gradually exhausted at a different pace, with the liver showing the first signs of oxidant damage, even before significant evidence exist in circulation. The current data further suggest that preventative antioxidant intervention may have a sparing effect on endogenous antioxidant mechanisms and preserve telomere length to delay disease progression-or at least the accelerated ageing known to exacerbate RA symptoms-although it did not seem to have a significant direct effect on the autoimmune activity.

Emerging Therapeutic Effects of Herbal Plants in Rheumatoid Arthritis

Rheumatoid arthritis is a chronic inflammatory autoimmune disease characterized by the failure of spontaneous resolution of inflammation with lifetime perseverance, becoming one of the major causes of disability in millions of people. It is mainly characterized by progressive erosion of cartilage in response to the formation of pannus leading to chronic polyarthritis and joint distortion. Early diagnosis and advances in molecular biology undoubtedly revolutionized therapeutic interventions in the past decade for better disease management. Despite favorable prospects, many patients still fail to respond to the current therapies urging a burning need to develop newer and safer medications. Herbal plants have been utilized since the ancient era and provided the base for massive bioactive compounds with flaunting therapeutic potential, many being advanced to drugs that are consumed worldwide for treating countless ailments. Scientific studies showed the involvement of several cellular mechanisms like oxidative stress suppression, downregulated synthesis of proinflammatory cytokines namely interleukins (IL-1, IL-6), TNF-α, NF-κB, demoted metalloproteinases induced cartilage destruction and augmentation of free radical scavenging and antioxidant activity in the treatment of rheumatoid arthritis. A plethora of active phytoconstituents like flavonoids, saponins, terpenes, alkaloids, lactones, etc, have been isolated from herbal plants with proven curative actions. The present review enlists some of the herbal drugs that can be used to amend the effects of rheumatoid arthritis and impart symptomatic relief to patients.

Immunogenic and inflammatory responses to citrullinated proteins are enhanced following modification with malondialdehyde-acetaldehyde adducts

BACKGROUND/OBJECTIVE

Malondialdehyde-acetaldehyde adducts (MAA) act as potent immune adjuvants and co-localize with citrullinated antigens in tissues effected by rheumatoid arthritis (RA). We sought to examine the role of MAA-adducts in promoting RA-related autoimmunity and inflammation.

METHODS

DBA/J1 mice were immunized with human serum albumin (HSA), HSA-MAA, citrullinated HSA (HSA-Cit), or HSA-MAA-Cit with subsequent measurement of serum anti-citrullinated protein antibody (ACPA) and anti-Cit T cell responses. Cellular binding of the same antigens was examined using THP-1 monocytes and Chinese Hamster Ovary (CHO) cells transfected with specific scavenger receptors (SRs: TLR4, SR-B2, SREC-1). The effects of these antigens on THP-1 activation were then examined by quantifying plate adherence, pro-inflammatory (TNFα, IL-1β, IL-10) cytokine release, and SR (CD14, SR-B2)/co-stimulatory molecule (CD80, HLA-DR) expression. Comparisons were completed using one-way ANOVA with Tukey's post-hoc test.

RESULTS

Mice immunized with co-modified HSA produced significantly higher ACPA concentrations than all other groups whereas T cell responses to citrullinated proteins were highest following immunization with HSA-MAA. Both transfected CHO and THP-1 cells demonstrated significantly higher binding of HSA-MAA-Cit vs. HSA or HSA-Cit. THP-1 cells exposed to HSA-MAA-Cit expressed significantly higher concentrations of TNFα, IL-1β, and IL-10 vs. all other groups. Furthermore, THP-1 cells demonstrated significantly increased plate adherence and higher expression of CD14, SR-B2, and HLA-DR following incubation with HSA-MAA-Cit vs. HSA or HSA-Cit.

CONCLUSION

These studies demonstrate that MAA-adduction of citrullinated antigen greatly enhances immune and cellular responses, potentially acting as a key co-factor in RA pathogenesis.

Platelets: emerging facilitators of cellular crosstalk in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease in which a variety of circulating pro-inflammatory cells and dysregulated molecules are involved in disease aetiology and progression. Platelets are an important cellular element in the circulation that can bind several dysregulated molecules (such as collagen, thrombin and fibrinogen) that are present both in the synovium and the circulation of patients with RA. Platelets not only respond to dysregulated molecules in their environment but also transport and express their own inflammatory mediators, and serve as regulators at the boundary between haemostasis and immunity. Activated platelets also produce microparticles, which further convey signalling molecules and receptors to the synovium and circulation, thereby positioning these platelet-derived particles as strategic regulators of inflammation. These diverse functions come together to make platelets facilitators of cellular crosstalk in RA. Thus, the receptor functions, ligand binding potential and dysregulated signalling pathways in platelets are becoming increasingly important for treatment in RA. This Review aims to highlight the role of platelets in RA and the need to closely examine platelets as health indicators when designing effective pharmaceutical targets in this disease.

Epigallocatechin 3-gallate attenuates arthritis by regulating Nrf2, HO-1, and cytokine levels in an experimental arthritis model

Epigallocatechin 3-gallate (EGCG) is a polyphenol that has been shown to have antioxidant and anti-inflammatory effects. In this study, collagen-induced arthritis (CIA) model, in Wistar albino rats, was used to elucidate the effect of EGCG on pathogenetic pathways in inflammatory arthritis. The levels of serum TNF-α, IL-17, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx); the expression levels of tissue heme oxygenase-1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2); histopathologically, perisynovial inflammation and cartilage-bone destruction were examined. In the sham group, serum TNF-α, IL-17, and MDA levels increased, while SOD, CAT, GPx levels, and the expressions of Nrf2 and HO-1 decreased. On the other hand, in the EGCG administered groups, serum TNF-α, IL-17, and MDA levels improved, while SOD, CAT, GPx levels and the expressions of Nrf2 and HO-1 increased. Moreover, histopathological analysis has shown that perisynovial inflammation and cartilage-bone destruction decreased in the EGCG administered groups. These results suggest that EGCG has an antiarthritic effect by regulating the oxidative-antioxidant balance and cytokine levels in the CIA model, which is a surrogate experimental model of rheumatoid arthritis.

Genkwanin ameliorates adjuvant-induced arthritis in rats through inhibiting JAK/STAT and NF-κB signaling pathways

BACKGROUND

Genkwanin is a flavone isolated from the traditional Chinese herb Daphne genkwa. Our previous work proved that four flavonoids (including genkwanin) isolated from D. genkwa (FFD) significantly improved the symptoms of arthritis in rat models. Recent studies have revealed that genkwanin exhibited anti-inflammatory and immunomodulatory activities, both of which were closely related to the pathology of rheumatoid arthritis (RA). Therefore, studying the anti-RA effects and mechanisms of genkwanin may give us insight into FFD's therapeutic effects on RA.

PURPOSE

This study aimed to investigate the anti-rheumatoid arthritis activity of genkwanin on adjuvant-induced arthritis (AIA) model in rats and explore the underlying mechanisms.

METHODS

The anti-rheumatoid arthritis activity of genkwanin was evaluated on AIA rat model by determining the paw swelling degrees and arthritis index scores, along with histopathological analysis of joint tissues. The serum cytokine levels were measured by ELISA method, and serum NO levels were measured by Griess method. The expression and phosphorylation levels of proteins in JAK/STAT and NF-κB signaling pathways were determined by western blot analysis and immunohistochemistry analysis.

RESULTS

Genkwanin significantly decreased the paw swelling and arthritis index in AIA rats and also decreased the inflammation and bone destruction in joint tissues. The serum TNF-α, IL-6, and NO concentrations were markedly reduced while the IL-10 concentration was markedly increased with the treatment of genkwanin. Genkwanin inhibited the activation of JAK/STAT and NF-κB signaling pathways in synovial tissues of AIA rats.

CONCLUSION

Genkwanin exerted anti-rheumatoid arthritis effects on AIA rats through inhibiting the activation of JAK/STAT and NF-κB signaling pathways. The results obtained in this work lead us to suggest that Genkwanin could play a crucial role on the previously demonstrated anti-rheumatoid arthritis activity of flavonoid extract of D. genkwa (namely FFD).

Inflammaging and Oxidative Stress in Human Diseases: From Molecular Mechanisms to Novel Treatments

It has been proposed that a chronic state of inflammation correlated with aging known as inflammaging, is implicated in multiple disease states commonly observed in the elderly population. Inflammaging is associated with over-abundance of reactive oxygen species in the cell, which can lead to oxidation and damage of cellular components, increased inflammation, and activation of cell death pathways. This review focuses on inflammaging and its contribution to various age-related diseases such as cardiovascular disease, cancer, neurodegenerative diseases, chronic obstructive pulmonary disease, diabetes, and rheumatoid arthritis. Recently published mechanistic details of the roles of reactive oxygen species in inflammaging and various diseases will also be discussed. Advancements in potential treatments to ameliorate inflammaging, oxidative stress, and consequently, reduce the morbidity of multiple disease states will be explored.

Role of hydrotherapy in the amelioration of oxidant-antioxidant status in rheumatoid arthritis patients

AIM

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease. Reactive oxygen species (ROS) are involved in the pathophysiology of RA. Moderate intensity exercises have been reported to have anti-oxidant and anti-inflammatory effects. The aim of this study was to evaluate the effect of hydrotherapy on oxidant-antioxidant status in RA patients.

METHODS

Forty RA patients and 30 age- and sex-matched healthy controls were included in this study. RA patients were subdivided into two groups: the first group (n = 20) received treatment with conventional RA drugs, while the second group (n = 20) received hydrotherapy along with the conventional drugs for a period of 12 weeks. Disease Activity Score of 28 joints (DAS-28), ROS level, protein oxidation, lipid peroxidation, DNA damage and the activities of antioxidant enzymes were evaluated before and after 12 weeks of treatment.

RESULTS

RA patients showed a significant change in the oxidative stress biomarkers (ROS, P < 0.01; ferric reducing antioxidant potential, P < 0.001; malondialdehyde, P < 0.01; protein carbonyl, P < 0.001; tail length, P < 0.05) and decrease in the activities of anti-oxidant enzymes (superoxide dismutase [SOD], P < 0.01; glutathione peroxidase [GPx], P < 0.001). Conventional drug treatment has not produced any significant change in these parameters. However, cotreatment of drugs with hydrotherapy has decreased protein, lipid and DNA oxidation by increasing the activities of antioxidant enzymes (SOD and GPx).

CONCLUSION

Our results indicate that hydrotherapy along with drugs has reduced the severity of disease (DAS-28) by ameliorating the oxidant-antioxidant status in RA patients. Thus, in addition to conventional drugs, RA patients should be advised to have hydrotherapy (moderate intensity exercise) in their treatment regimen.

Melatonin and its metabolites vs oxidative stress: From individual actions to collective protection

Oxidative stress (OS) represents a threat to the chemical integrity of biomolecules including lipids, proteins, and DNA. The associated molecular damage frequently results in serious health issues, which justifies our concern about this phenomenon. In addition to enzymatic defense mechanisms, there are compounds (usually referred to as antioxidants) that offer chemical protection against oxidative events. Among them, melatonin and its metabolites constitute a particularly efficient chemical family. They offer protection against OS as individual chemical entities through a wide variety of mechanisms including electron transfer, hydrogen transfer, radical adduct formation, and metal chelation, and by repairing biological targets. In fact, many of them including melatonin can be classified as multipurpose antioxidants. However, what seems to be unique to the melatonin's family is their collective effects. Because the members of this family are metabolically related, most of them are expected to be present in living organisms wherever melatonin is produced. Therefore, the protection exerted by melatonin against OS may be viewed as a result of the combined antioxidant effects of the parent molecule and its metabolites. Melatonin's family is rather exceptional in this regard, offering versatile and collective antioxidant protection against OS. It certainly seems that melatonin is one of the best nature's defenses against oxidative damage.

Modulation of the Oxidative Stress and Lipid Peroxidation by Endocannabinoids and Their Lipid Analogues

Growing evidence supports the pivotal role played by oxidative stress in tissue injury development, thus resulting in several pathologies including cardiovascular, renal, neuropsychiatric, and neurodegenerative disorders, all characterized by an altered oxidative status. Reactive oxygen and nitrogen species and lipid peroxidation-derived reactive aldehydes including acrolein, malondialdehyde, and 4-hydroxy-2-nonenal, among others, are the main responsible for cellular and tissue damages occurring in redox-dependent processes. In this scenario, a link between the endocannabinoid system (ECS) and redox homeostasis impairment appears to be crucial. Anandamide and 2-arachidonoylglycerol, the best characterized endocannabinoids, are able to modulate the activity of several antioxidant enzymes through targeting the cannabinoid receptors type 1 and 2 as well as additional receptors such as the transient receptor potential vanilloid 1, the peroxisome proliferator-activated receptor alpha, and the orphan G protein-coupled receptors 18 and 55. Moreover, the endocannabinoids lipid analogues N-acylethanolamines showed to protect cell damage and death from reactive aldehydes-induced oxidative stress by restoring the intracellular oxidants-antioxidants balance. In this review, we will provide a better understanding of the main mechanisms triggered by the cross-talk between the oxidative stress and the ECS, focusing also on the enzymatic and non-enzymatic antioxidants as scavengers of reactive aldehydes and their toxic bioactive adducts.

Systemic Inflammatory Response and Atherosclerosis: The Paradigm of Chronic Inflammatory Rheumatic Diseases

Patients with Chronic Inflammatory Rheumatic diseases (CIRD) are at increased risk of cardiovascular disease (CVD), ascribed not only to classical risk factors, but also to the presence of chronic systemic inflammatory response. Αtherosclerosis, the cornerstone of CVD, is known to be accelerated in CIRD; rheumatoid arthritis promotes atheromatosis and associates with preclinical atherosclerosis equivalent to Diabetes Mellitus, which also seems to apply for systemic lupus erythematosus. Data on ankylosing spondylitis and psoriatic arthritis, albeit more limited, also support an increased CV risk in these patients. The association between inflammation and atherosclerosis, has been thoroughly investigated in the last three decades and the role of inflammation in the pathogenesis and progression of atherogenesis has been well established. Endothelial dysfunction, oxidative stress in vascular endothelial cells and macrophage accumulation, toll-like receptor signaling, NLPR-3 formation and subsequent pro-inflammatory cytokine production, such as TNFa, IL-1β, IL-6, and TNF-like cytokine 1A, are few of the mechanisms implicated in the atherogenic process. Moreover, there is evidence that anti-inflammatory biologic drugs, such as anti-TNF and anti-IL1β agents, can decelerate the atherogenic process, thus setting new therapeutic targets for early and effective disease control and suppression of inflammation, in addition to aggressive management of classical CV risk factors.

Associations between D3R expression in synovial mast cells and disease activity and oxidant status in patients with rheumatoid arthritis

Dopamine D3 receptor (D3R) on immune cells is involved in the pathogenesis of rheumatoid arthritis (RA). Mast cells (MCs) are currently identified as important effector cells in synovial inflammation of RA, but little is known about the role of D3R on synovial MCs in the pathogenesis of RA. Several inflammatory cells in the synovium induce reactive oxygen species (ROS) formation which are involved in the progression of RA. However, it is unclear whether D3R on synovial MCs is related to the levels of ROS in RA patients. In this study, a total of 73 patients with RA were divided into three groups according to disease activity DAS28 scores. The number of cases in group 1, group 2, and group 3 was 19, 26, and 28, respectively. We examined D3R-positive MC numbers in the synovial fluid and ROS levels in each group of RA patients, and we also analyzed the association of D3R-positive MC numbers with RA disease activity and ROS levels. MDA and protein carbonylation in the serum and synovial fluid were measured to reflect the level of lipid peroxidation and protein oxidation, respectively. Additionally, superoxide dismutase (SOD) and catalase (CAT) in the serum and synovial fluid were used to be markers of antioxidant levels. Our results showed that D3R-positive MCs in the synovial fluid showed a declining trend with the increased disease activity DAS28 score in RA patients. There was negative correlation between D3R-positive MC numbers in the synovial fluid and disease severity DAS28 score of RA patients. Moreover, D3R-positive MC numbers in the synovial fluid were negatively correlated with the level of MDA and protein carbonylation while were positively correlated with antioxidant levels such as SOD and CAT in RA patients. Our results suggested that D3R on MCs may be involved in ROS-mediated pathogenesis of RA.

Metabolic syndrome and the decreased levels of uric acid by leflunomide favor redox imbalance in patients with rheumatoid arthritis

Oxidative stress plays a role in the pathophysiology of rheumatoid arthritis (RA). The aim of the present study was to verify the influence of metabolic syndrome (MetS) and disease-modifying antirheumatic drugs on nitrosative and oxidative biomarkers in patients with RA. A total of 177 patients with RA and 150 healthy volunteers participated in this study, which measured lipid hydroperoxides, advanced oxidation protein products (AOPP), nitric oxide metabolites (NOx), carbonyl protein, total radical-trapping antioxidant parameter (TRAP), uric acid (UA), and C-reactive protein (CRP). NOx and the NOx/TRAP ratio were significantly increased in RA, while no significant differences in lipid hydroperoxides, AOPP, UA, and TRAP levels were found between both groups. Treatment with leflunomide was associated with increased levels of carbonyl protein, and lowered levels in TRAP and UA, while the NOx/TRAP ratio further increased. NOx and the NOx/TRAP ratio were significantly higher in women than in men, while TRAP and UA were significantly lower in women. MetS was accompanied by increased AOPP and UA levels. RA was best predicted by increased NOx/TRAP ratio, CRP, and BMI. In conclusion, our data demonstrated that NOx and NOx/TRAP are strongly associated with RA physiopathology. Our findings suggest that inhibition of iNOS may become an interesting therapeutic approach for the treatment of RA. In addition, the presence of MetS and a decrease in levels of UA by leflunomide favor redox imbalance in RA patients. More studies are needed to evaluate the impact of antioxidant capacity reduction on RA progression.

Using chemiluminescence to determine whole blood antioxidant capacity in rheumatoid arthritis and Parkinson's disease patients

The consequences of oxidative stress and inflammation are implicated in a wide range of diseases, including rheumatoid arthritis and Parkinson's disease. The status of antioxidant capacity in rheumatoid arthritis and Parkinson's disease remains unclear, in part due to common practice of assaying erythrocytes separately to plasma. This method removes any synergistic interactions between plasma and erythrocyte-based antioxidants. The experiments in this report tested antioxidant capacity in whole blood, erythrocytes and plasma by group and disease stage. Medically diagnosed patients were recruited along with appropriate control group participants. Fasting venous blood was assayed using chemiluminescence methods for: time to maximum light emitted, maximum light emitted, and plasma antioxidant capacity in vitamin E analogue units. Here we demonstrate that whole blood exhibits higher antioxidant capacity than either plasma or erythrocytes assayed separately. We report increased oxidative stress in the blood of rheumatoid arthritis patients by group (p = 0.018, p = 0.049). We show increased antioxidant capacity in Parkinson's disease patients by group (p < 0.001). For later stage Parkinson's disease patients, we report reduced oxidative stress (p = 0.025), and increased antioxidant capacity and for erythrocytes (p < 0.001, p = 0.004) and whole blood (p < 0.001, p = 0.003). Early stage Parkinson's disease showed higher antioxidant capacity on only one measure (p = 0.008). Whole blood chemiluminescence is a useful technique for determining redox status in disease and might help clarify the role of oxidative stress in rheumatoid arthritis and Parkinson's disease.

Association of oxidative stress with clinical characteristics in patients with rheumatoid arthritis

BACKGROUND

Few studies examining the association between oxidative stress and clinical parameters or disease activity in patients with rheumatoid arthritis (RA) are available. Therefore, the objective of this study was to test whether oxidative stress has any association with clinical parameters and disease activity in patients with RA.

MATERIALS AND METHODS

In this post hoc cross-sectional study, 45 patients with RA treated with traditional disease-modifying antirheumatic drugs (DMARDs) ± low-dose glucocorticoids ± nonsteroidal analgesics for at least 3 months were analysed. Oxidative stress parameters were malondialdehyde (MDA), superoxide dismutase (SOD), antioxidant potential (AOP) and nonenzymatic superoxide radical scavenger activity (NSSA). Clinical parameters were pain, patient global assessment, physician global assessment, Health Assessment Questionnaire (HAQ), and disease activity score (DAS28).

RESULTS

Plasma NSSA levels were significantly inversely correlated with tender joints count (r = -.304; P = .042), swollen joints count (r = -.342; P = .021) and DAS28 (r = -.396; P = .009). There were no significant correlations between MDA/SOD/AOP and any of clinical parameters or DAS28 (P > .05 for all). Multiple regression analysis revealed that NSSA was an independent variable of DAS28 (β=-.243, P = .016).

CONCLUSION

The preliminary results demonstrate that plasma NSSA levels were inversely correlated with tender and swollen joints count and DAS28 and that NSSA was independently associated with DAS28, in patients with RA treated with traditional DMARDs; and provide initial support that NSSA may be used as a biomarker of disease activity in patients with RA.

Isotypes of autoantibodies against differentially expressed novel malondialdehyde-modified peptide adducts in serum of Taiwanese women with rheumatoid arthritis

This study identified and validated four differentially expressed novel malondialdehyde (MDA)-modified peptide adducts and evaluated autoantibodies against native and MDA-modified peptides among Taiwanese women patients with rheumatoid arthritis (RA), osteoarthritis (OA) and healthy controls (HCs). Ig kappa chain C region^76-99, alpha-1-antitrypsin^284-298, alpha-2-macroglobulin^824-841, and apolipoprotein B-100^4022-4040 exhibiting 2-fold differences in relative modification ratios were identified by concanavalin A (Con A) affinity chromatography, 1D SDS-PAGE, in-gel digestion, nano-LC/MS/MS and nano-LC/MS using pooled serum-derived Con A-captured proteins from 9 RA and 9 age-matched HCs. Furthermore, the levels of proteins, serum MDA, and MDA-modified protein adducts were further validated against individual serum from 20 RA and 20 HCs, and autoantibodies against native and their MDA-modified peptides used 45 RA, 30 OA and 45 HCs. Levels of serum MDA and MDA-modified protein adducts were significantly higher in RA than HCs but protein levels were not significantly different. Serum Igs G and M against MDA-modified peptides showed better diagnostic performance in differentiating among patients with RA, OA and HCs, with an area under the receiver operating characteristic curve of 0.96-0.98, sensitivity of 88.9%-97.8%, and specificity of 88.9%-100%. Autoantibodies against MDA-modified epitopes become useful clinical biomarkers for RA.

BIOLOGICAL SIGNIFICANCE

By using a label-free relative quantitative proteomic analysis of concanavalin A (Con A)-bound serum samples, the current study discovered and validated malondialdehyde (MDA)-modified peptide adducts as novel biomarkers for differentiating between rheumatoid arthritis (RA) patients and healthy controls (HCs). In addition, the serum levels of MDA, proteins, and MDA-modified protein adducts as well as the MDA modification of proteins were determined. Isotypes of autoantibodies against MDA-modified peptide adducts can be used as serological biomarkers for further discriminating among RA patients, osteoarthritis patients and HCs. This strategy can become the basis for identifying potential diagnostic and pathological biomarkers for RA.

Protective Effect of Pinitol Against Inflammatory Mediators of Rheumatoid Arthritis via Inhibition of Protein Tyrosine Phosphatase Non-Receptor Type 22 (PTPN22)

Background

The aim of the current study was to explore the anti-arthritic effect of pinitol via assessing its effect on various inflammatory mediators and its possible mechanism of action.

Material/Method

We assessed the anti-arthritic effect of pinitol in a formaldehyde- and CFA-induced arthritic model in Wistar Swiss albino strain rats divided into 6 groups. The rats received different doses of pinitol and indomethacin for 28 days. The arthritic index and body weight were determined at regular intervals, together with hepatic, hematological, and antioxidant parameters. The expression of proinflammatory cytokines (e.g., IL-6, TNF-α, and IL-1β) and inflammatory mediators (e.g., COX-2 and VEGF) were also estimated with histopathological evaluation of the joint tissue of rats. A docking study of pinitol with PTPN22 was also carried out.

Results

The CFA-induced model rats developed redness and nodules in the tail and front paws, and the arthritic control (AC) group rats showed similar symptoms, which were decreased by pinitol administration. The body weight of AC group rats was decreased, while pinitol-treated rats showed considerably increased body weight. Hematological, hepatic, and antioxidant parameters were altered by pinitol in a dose-dependent manner. Pinitol significantly decreased the elevated concentration of proinflammatory cytokines and inflammatory mediators, with improvement in histopathological condition. The docking study suggested that pinitol efficiently interacted with PTPN22 via Arg59, Tyr60, Leu106, and Lys138 by creating close interatomic hydrogen bonds and hydrophobic contacts.

Conclusions

Pinitol showed anti-arthritic effects via reduction of proinflammatory cytokines and inflammatory mediators via inhibition of PTPN22.

Photobiomodulation therapy associated with treadmill training in the oxidative stress in a collagen-induced arthritis model

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by chronic and systemic inflammation, which leads to the destruction of the cartilage and bone and affects tissues in multiple joints. Oxidative stress has been implicated with regards to involvement in various disease conditions, such as diabetes mellitus and neurodegenerative, respiratory, cardiovascular, and RA diseases. In vivo experimental studies using photobiomodulation therapy (PBMT) have shown positive effects in reducing lipid peroxidation and in increasing antioxidant activity. The regular practice of physical exercise has also been reported to be a beneficial treatment capable of reducing oxidative damage. Thus, the aim of this study was to analyze the effects of photobiomodulation therapy at 2- and 4-J doses associated with physical exercise on oxidative stress in an experimental model of RA in protein expression involving superoxide dismutase (SOD), glutathione peroxidase (GPX), and/or catalase (CAT) on thiobarbituric acid reactive substances (TBARS). In this study, 24 male Wistar rats divided into four groups were submitted to an RA model (i.e., collagen-induced arthritis, CIA), with the first immunization performed at the base of the tail on days 0 and 7 were included. After 28 days, a third intraarticular dose was administered in both knees of the animals. After the last induction, PBMT was started immediately, transcutaneously at two points (i.e., the medial and lateral), with a total of 15 applications. Treadmill exercise was also started the day after the last induction, and lasted for 5 weeks. With respect to results, we obtained the decreases in the lipid peroxidation and the increases of the antioxidant activities of SOD, GPX and CAT, with physical exercise associated to PBMT in doses of 2 and 4 J. In conclusion, physical exercise associated with PBMT decreases lipid peroxidation and increases antioxidant activity.

Major involvement of bacterial components in rheumatoid arthritis and its accompanying oxidative stress, systemic inflammation and hypercoagulability

We review the evidence that infectious agents, including those that become dormant within the host, have a major role to play in much of the etiology of rheumatoid arthritis and the inflammation that is its hallmark. This occurs in particular because they can produce cross-reactive (auto-)antigens, as well as potent inflammagens such as lipopolysaccharide that can themselves catalyze further inflammagenesis, including via β-amyloid formation. A series of observables coexist in many chronic, inflammatory diseases as well as rheumatoid arthritis. They include iron dysregulation, hypercoagulability, anomalous morphologies of host erythrocytes, and microparticle formation. Iron dysregulation may be responsible for the periodic regrowth and resuscitation of the dormant bacteria, with concomitant inflammagen production. The present systems biology analysis benefits from the philosophical idea of "coherence," that reflects the principle that if a series of ostensibly unrelated findings are brought together into a self-consistent narrative, that narrative is thereby strengthened. As such, we provide a coherent and testable narrative for the major involvement of (often dormant) bacteria in rheumatoid arthritis.

Pharmacological studies on the anti-inflammatory and immunomodulatory role of pentoxifylline and its interaction with nitric oxide (NO) in experimental arthritis in rats

AIM

Present study was designed to evaluate protective effects of pentoxifylline and its potentiation with low dose of nitric oxide (NO) modulators in adjuvant-induced experimental arthritis in rats.

METHOD

Wistar rats (200-300 g, n = 8 per group) of both sexes were used in the study. On day "0" experimental arthritis was induced by injecting 0.2 ml of Complete Freund's adjuvant (CFA) in sub-planter region of right hind paw of animals. Pentoxifylline treatment alone and in combination with NO modulators was given (i.p.) from day 14 to 28. Various arthritic parameters were recorded and blood and joint synovial fluid was collected for biochemical analysis.

RESULTS

CFA inoculation significantly increases (1) arthritic index (2) ankle diameter (3) paw volume (4) histopathology score (5) serum TNF-α, IL-6, IL-1β and synovial TNF-α levels (p < 0.001) (6) serum Th₁ and Th₂ cytokine levels g) MDA levels in rat paw tissue homogenates (7) serum NF-κB levels. Significant decrease in serum IL-10 levels and SOD activity was observed in rats after CFA inoculation. Decrease in body weight and suppressed general quality of life of CFA inoculated rats was also observed. These CFA-induced arthritic changes were significantly reversed by pentoxifylline alone and in combination with low dose of NO modulators (p < 0.05).

CONCLUSION

These results are suggestive of protective effects of pentoxifylline and its potentiation in combination with low dose of NO modulators. These results may provide new pharmacological therapy for management of rheumatoid arthritis (RA).