Enhanced recognition of reactive oxygen species damaged human serum albumin by circulating systemic lupus erythematosus autoantibodies

Plasma/Serum Oxidant Parameters in Systemic Lupus Erythematosus Patients: A Systematic Review and Meta-Analysis

Most published results have revealed variations in the association of serum/plasma levels of malondialdehyde (MDA), apolipoprotein B (ApoB), and oxidized low-density lipoprotein (OxLDL) and systemic lupus erythematosus (SLE). This study was performed to establish MDA, ApoB, and OxLDL levels in systemic lupus erythematosus (SLE) patients. Electronic databases were searched for the included articles up to 27th February 2023. The meta-analysis included 48 articles with 2358 SLE patients and 2126 healthy controls considered for MDA, ApoB, and OxLDL levels. There were significantly higher MDA, ApoB, and OxLDL levels in SLE patients than those in the control groups. Subgroup analysis indicated that European/American SLE patients and patients of both ages <36 and ≥36 exhibited higher MDA, ApoB, and OxLDL levels. Arab and Asian SLE patients had higher ApoB and MDA/OxLDL levels. African SLE patients recorded higher OxLDL levels than the control groups. SLE patients with a body mass index (BMI) of ≥23 and a disease duration of <10 recorded significantly higher MDA, ApoB, and OxLDL levels. Patients with systemic lupus erythematosus disease activity index (SLEDAI) ≥8 of SLE had higher MDA and ApoB levels, whereas SLE patients with SLEDAI <8 showed significantly higher ApoB levels. Patients with BMI <23 of SLE had higher MDA and OxLDL levels. This study established significantly higher MDA, ApoB, and OxLDL levels in SLE patients, suggesting a possible role of MDA, ApoB, and OxLDL in the disease.

Thymoquinone provides structural protection of human hemoglobin against oxidative damage: Biochemical studies

Hydroxyl radicals (OH^.) are one of the most active reactive oxidants recognized for their deleterious effects to cause protein oxidative damage. Thymoquinone, a monoterpene molecule abundantly present in black cumin and known for its pharmacological activities, but its activity against the OH^.-induced protein oxidative damage has never been explored. This study determined the therapeutic potential of thymoquinone against OH^.-induced oxidative human hemoglobin damage. Novel data demonstrated that thymoquinone provides structural protection of hemoglobin against oxidative damage. Treatment of hemoglobin with OH^. induces hypochromicity at 280 and 405 nm, whereas thymoquinone reversed these hypochromic effects. In addition, OH^. cause significant reduction in tryptophan fluorescence, however thymoquinone also reversed these damaging effects. Thymoquinone also reduces OH^.-induced hydrophobicity and also reduces OH^.-induced carbonylation. Moreover, it also inhibits thermal stabilization of OH^.-hemoglobin complex. SDS-PAGE of unmodified hemoglobin showed four bands, which disappeared upon OH^. treatment and these changes were also retained by thymoquinone. In conclusion, this is the first study that shows the therapeutic potential of thymoquinone against OH^.-induced oxidative damage in human hemoglobin.

Protective Potential of Uric Acid, Folic Acid, Glutathione and Ascorbic Acid Against the Formation of Toxic Met-Myoglobin

BACKGROUND

Myoglobin is an oxygen binding protein and its dysfunction has been associated with the pathology of several human disorders. This study was undertaken to investigation the role of hydrogen peroxide (H2O2) in the formation of met-myoglobin and the protective potential of four different reductants such as uric acid, folic acid, glutathione and ascorbic acid were also tested against met-myoglobin formation.

METHODS

Human myoglobin was treated with H2O2 in-vitro in order to prepare met-myoglobin. The generation of met-myoglobin was confirmed by UV-visible spectroscopy and its stability was analysed by the treatment of human myoglobin with H2O2 at varying pH or time. High performance liquid chromatography (HPLC) was used to determine the oxidatively modified heme products in met-myoglobin. Spectroscopic analysis was used to identify the protective potential of uric acid, folic acid, glutathione and ascorbic acid against the formation of met-myoglobin.

RESULTS

The novel data of this study showed that H2O2 induced extensive damage of myoglobin but the treatment with uric acid, folic acid, glutathione or ascorbic acid provides protection of myoglobin against H2O2 induced oxidative damaged. The study apparently proved the protective potential of all these compounds against the toxicity produced by H2O2.

CONCLUSION

This is the first study that shows uric acid, folic acid, glutathione and ascorbic acid provide protection against the generation of toxic met-myoglobin and might be used therapeutically to modify the blood conditions in order to prevent the progression of human disorders associated with myoglobin dysfunction.

Oxidative Stress Biomarkers and Peripheral Endothelial Dysfunction in Rheumatoid Arthritis: A Monocentric Cross-Sectional Case-Control Study

Previous studies have suggested that oxidative stress may heighten atherosclerotic burden in rheumatoid arthritis (RA), but direct evidence is lacking.

OBJECTIVE

To evaluate the relationship between established plasma oxidative stress biomarkers and peripheral endothelial dysfunction (ED), a marker of early atherosclerosis, in RA.

METHODS

Paroxonase-1 (PON-1), protein-SH (PSH), and malondialdehyde (MDA) were measured in 164 RA patient s and 100 age- and sex-matched healthy controls without previous cardiovascular events. Peripheral ED, evaluated by flow-mediated pulse amplitude tonometry, was defined by log-transformed reactive hyperemia index (Ln-RHI) values < 0.51.

RESULTS

PON-1 activity and PSH concentrations were significantly reduced in RA patients compared to controls. In regression analysis, increased plasma MDA levels were significantly associated with reduced Ln-RHI [B coefficient (95% CI) = -0.003 (-0.005 to -0.0008), p = 0.008] and the presence of peripheral ED (OR (95% CI) = 1.75 (1.06-2.88), p = 0.028). Contrary to our expectations, increased PON-1 activity was significantly associated, albeit weakly, with the presence of ED (OR (95% CI) = 1.00 (1.00-1.01), p = 0.017).

CONCLUSIONS

In this first evidence of a link between oxidative stress and markers of atherosclerosis, MDA and PON-1 showed opposite associations with peripheral vasodilatory capacity and the presence of ED in RA. Further studies are needed to determine whether this association predicts atherosclerotic events in the RA population.

A, Alzolibani AA. Filaggrin, major basic protein and leukotriene B4: Biomarkers for adult patients of bronchial asthma, atopic dermatitis and allergic rhinitis

Bronchial asthma (BA), atopic dermatitis (AD), and allergic rhinitis (AR) are well known atopic disorders with complex etiologies. This study was undertaken to investigate the role of filaggrin, eosinophil major basic protein (MBP) and leukotriene B4 (LTB4) in patients with BA, AD, and AR. Sera from 1,246 patients with different atopic disorders and 410 normal healthy controls were collected and were evaluated for filaggrin, MBP and LTB4 by specific sandwich ELISAs, whereas immunoglobulin E (IgE) was used as a positive control for atopic patients. Serum analysis showed that filaggrin levels were remarkably high in patients with AD and in patients with multiple (mixed) atopic disorders (p < 0.001), whereas its levels in BA and AR patients were low but much higher than in normal human sera (p < 0.01). MBP levels were also high in AR, BA and mixed atopic patients, whereas AD patients showed no increase of MBP (p > 0.05). In contrast, LTB4 level was found to be significantly low in all tested atopic patients groups as compared to the levels of LTB4 present in normal human sera (p < 0.001). In conclusion, these findings support an association between filaggrin, MBP or LTB4 and atopic disorders. Our data strongly suggest that filaggrin, MBP or LTB4 might be useful in elucidating the mechanisms involved in the pathogenesis of these atopic disorders.

Evaluation of Lymphocyte Response to the Induced Oxidative Stress in a Cohort of Ageing Subjects, including Semisupercentenarians and Their Offspring

The production of reactive oxygen species (ROS) may promote immunosenescence if not counterbalanced by the antioxidant systems. Cell membranes, proteins, and nucleic acids become the target of ROS and progressively lose their structure and functions. This process could lead to an impairment of the immune response. However, little is known about the capability of the immune cells of elderly individuals to dynamically counteract the oxidative stress. Here, the response of the main lymphocyte subsets to the induced oxidative stress in semisupercentenarians (CENT), their offspring (OFF), elderly controls (CTRL), and young individuals (YO) was analyzed using flow cytometry. The results showed that the ratio of the ROS levels between the induced and noninduced (I/NI) oxidative stress conditions was higher in CTRL and OFF than in CENT and YO, in almost all T, B, and NK subsets. Moreover, the ratio of reduced glutathione levels between I/NI conditions was higher in OFF and CENT compared to the other groups in almost all the subsets. Finally, we observed significant correlations between the response to the induced oxidative stress and the degree of methylation in specific genes on the oxidative stress pathway. Globally, these data suggest that the capability to buffer dynamic changes in the oxidative environment could be a hallmark of longevity in humans.

The SOD1 transgene expressed in erythroid cells alleviates fatal phenotype in congenic NZB/NZW-F1 mice

Oxidative stress due to a superoxide dismutase 1 (SOD1) deficiency causes anemia and autoimmune responses, which are phenotypically similar to autoimmune hemolytic anemia (AIHA) and systemic lupus erythematosus (SLE) in C57BL/6 mice and aggravates AIHA pathogenesis in New Zealand black (NZB) mice. We report herein on an evaluation of the role of reactive oxygen species (ROS) in a model mouse with inherited SLE, that is, F1 mice of the NZB × New Zealand white (NZW) strain. The ROS levels within red blood cells (RBCs) of the F1 mice were similar to the NZW mice but lower compared to the NZB mice throughout adult period. Regarding SLE pathogenesis, we examined the effects of an SOD1 deficiency or the overexpression of human SOD1 in erythroid cells by establishing corresponding congenic F1 mice. A SOD1 deficiency caused an elevation in ROS production, methemoglobin content, and hyperoxidation of peroxiredoxin in RBC of the F1 mice, which were all consistent with elevated oxidative stress. However, while the overexpression of human SOD1 in erythroid cells extended the life span of the congenic F1 mice, the SOD1 deficiency had no effect on life span compared to wild-type F1 mice. It is generally recognized that NZW mice possess a larval defect in the immune system and that NZB mice trigger an autoimmune reaction in the F1 mice. Our results suggest that the oxidative insult originated from the NZB mouse background has a functional role in triggering an aberrant immune reaction, leading to fatal responses in F1 mice.

Genetic, Immune-Inflammatory, and Oxidative Stress Biomarkers as Predictors for Disability and Disease Progression in Multiple Sclerosis

The aim of this study was to evaluate the TNFβ NcoI polymorphism (rs909253) and immune-inflammatory, oxidative, and nitrosative stress (IO&NS) biomarkers as predictors of disease progression in multiple sclerosis (MS). We included 212 MS patients (150 female, 62 male, mean (±standard deviation (SD)) age = 42.7 ± 13.8 years) and 249 healthy controls (177 female, 72 male, 36.8 ± 11 years). The disability was measured the Expanded Disability Status Scale (EDSS) in 2006 and 2011. We determined the TNFβ NcoI polymorphism and serum levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, IL-4, IL-10, and IL-17, albumin, ferritin, and plasma levels of lipid hydroperoxides (CL-LOOH), carbonyl protein, advanced oxidation protein products (AOPPs), nitric oxide metabolites (NOx), and total radical-trapping antioxidant parameter (TRAP). The mean EDSS (±SD) in 2006 was 1.62 ± 2.01 and in 2011 3.16 ± 2.29, and disease duration was 7.34 ± 7.0 years. IL-10, TNF-α, IFN-γ, AOPP, and NOx levels were significantly higher and IL-4 lower in MS patients with a higher 2011 EDSS scores (≥3) as compared with those with EDSS < 3. The actual increases in EDSS from 2006 to 2011 were positively associated with TNF-α and IFN-γ. Increased IFN-γ values were associated with higher pyramidal symptoms and increased IL-6 with sensitive symptoms. Increased carbonyl protein and IL-10 but lowered albumin levels predicted cerebellar symptoms. The TNFB1/B2 genotype decreased risk towards progression of pyramidal symptoms. Treatments with IFN-β and glatiramer acetate significantly reduced TNF-α but did not affect the other IO&NS biomarkers or disease progression. Taken together, IO&NS biomarkers and NcoI TNFβ genotypes predict high disability in MS and are associated with different aspects of disease progression. New drugs to treat MS should also target oxidative stress pathways.

Oxidative stress as a potential causal factor for autoimmune hemolytic anemia and systemic lupus erythematosus

The kidneys and the blood system mutually exert influence in maintaining homeostasis in the body. Because the kidneys control erythropoiesis by producing erythropoietin and by supporting hematopoiesis, anemia is associated with kidney diseases. Anemia is the most prevalent genetic disorder, and it is caused by a deficiency of glucose 6-phosphate dehydrogenase (G6PD), for which sulfhydryl oxidation due to an insufficient supply of NADPH is a likely direct cause. Elevated reactive oxygen species (ROS) result in the sulfhydryl oxidation and hence are another potential cause for anemia. ROS are elevated in red blood cells (RBCs) under superoxide dismutase (SOD1) deficiency in C57BL/6 mice. SOD1 deficient mice exhibit characteristics similar to autoimmune hemolytic anemia (AIHA) and systemic lupus erythematosus (SLE) at the gerontic stage. An examination of AIHA-prone New Zealand Black (NZB) mice, which have normal SOD1 and G6PD genes, indicated that ROS levels in RBCs are originally high and further elevated during aging. Transgenic overexpression of human SOD1 in erythroid cells effectively suppresses ROS elevation and ameliorates AIHA symptoms such as elevated anti-RBC antibodies and premature death in NZB mice. These results support the hypothesis that names oxidative stress as a risk factor for AIHA and other autoimmune diseases such as SLE. Herein we discuss the association between oxidative stress and SLE pathogenesis based mainly on the genetic and phenotypic characteristics of NZB and New Zealand white mice and provide insight into the mechanism of SLE pathogenesis.

Preferential recognition of hydroxyl radical-modified superoxide dismutase by circulating autoantibodies in patients with alopecia areata

Background

Alopecia areata (AA) is a common form of localized, non-scarring hair loss. The cause of AA is unknown but reports suggest an autoimmune etiology, where oxygen free radicals play an important role.

Objective

The aim of this study was to investigate the role of a hydroxyl radicals (·OH)-modified antioxidant enzyme, superoxide dismutase (SOD), in AA autoimmunity.

Methods

SOD was modified by ·OH radicals. Binding characteristics of autoantibodies in AA patients (n=26) against ·OH-modified SOD (·OH-SOD) were evaluated by immunoassays and the results were compared with those of healthy, age-matched controls (n=30). The effects of ·OH radicals on immunoglobulin G (IgG) isolated from AA patients were studied.

Results

Highly specific binding to ·OH-SOD was observed in 32% of the samples of patient sera, whereas normal human sera showed negligible binding with either antigen. Competitive inhibition immunoassays reiterated the results from direct binding. Protein-A-purified IgG from AA patients (AA-IgG) also showed strong binding to ·OH-SOD as compared to IgG from normal human controls (p<0.001). In addition, AA-IgG from patients with alopecia universalis recognized ·OH-SOD to a greater extent than did AA-IgG from patients with the patchy, persistent type of alopecia. Furthermore, sera from AA patients had lower levels of SOD activity as compared to control sera.

Conclusion

This is the first report showing an association between ·OH-modified SOD and AA. These novel results demonstrate that ·OH radical-mediated changes in SOD present unique neo-epitopes that might contribute to antigen-driven antibody induction in AA.

Chronic hydroxychloroquine improves endothelial dysfunction and protects kidney in a mouse model of systemic lupus erythematosus

Hydroxychloroquine has been shown to be efficacious in the treatment of autoimmune diseases, including systemic lupus erythematosus. Hydroxychloroquine-treated lupus patients showed a lower incidence of thromboembolic disease. Endothelial dysfunction, the earliest indicator of the development of cardiovascular disease, is present in lupus. Whether hydroxychloroquine improves endothelial function in lupus is not clear. The aim of this study was to analyze the effects of hydroxychloroquine on hypertension, endothelial dysfunction, and renal injury in a female mouse model of lupus. NZBWF1 (lupus) and NZW/LacJ (control) mice were treated with hydroxychloroquine 10 mg/kg per day by oral gavage, or with tempol and apocynin in the drinking water, for 5 weeks. Hydroxychloroquine treatment did not alter lupus disease activity (assessed by plasma double-stranded DNA autoantibodies) but prevented hypertension, cardiac and renal hypertrophy, proteinuria, and renal injury in lupus mice. Aortae from lupus mice showed reduced endothelium-dependent vasodilator responses to acetylcholine and enhanced contraction to phenylephrine, which were normalized by hydroxychloroquine or antioxidant treatments. No differences among all experimental groups were found in both the relaxant responses to acetylcholine and the contractile responses to phenylephrine in rings incubated with the nitric oxide synthase inhibitor N(G)-nitro-l-arginine methyl ester. Vascular reactive oxygen species content and mRNA levels of nicotinamide adenine dinucleotide phosphate oxidase subunits NOX-1 and p47(phox) were increased in lupus mice and reduced by hydroxychloroquine or antioxidants. Chronic hydroxychloroquine treatment reduced hypertension, endothelial dysfunction, and organ damage in severe lupus mice, despite the persistent elevation of anti-double-stranded DNA, suggesting the involvement of new additional mechanisms to improve cardiovascular complications.

Biochemical and immunological studies on erythrocytes superoxide dismutase modified by nitric oxide in patients with alopecia areata: Implications in alopecia patchy persistent and alopecia universalis

Alopecia areata (AA) is a non-scarring hair loss disorder that ranges in severity from patchy loss of scalp hair (AA patchy persistent; AAP) to loss of all scalp and body hair (alopecia universalis; AU). The cause of AA is unknown but most evidences support that AA has an autoimmune etiology, where free radicals play an important role. This study was undertaken to investigate the role of nitric oxide (NO) modified erythrocytes superoxide dismutase (eSOD) in AA. Data revealed that NO-induced damage in eSOD caused alteration in hydrophobic or aromatic amino acids and protein carbonyl contents. NO-specific quencher, carboxyl-PTIO further reiterates NO-modifications. Specificity of antibodies from AA patients (n=26) was analyzed toward NO-modified eSOD (NO-eSOD) and their results were compared with healthy controls (n=30). Protein-A purified IgG of AA patients (AA-IgG) showed strong binding to NO-eSOD in comparison with IgG from controls. In addition, AA-IgG from patients with AU recognized NO-eSOD in a greater extent as compared to AA-IgG from patients with AAP. Furthermore, AU patients' sera contained higher levels of NO or carbonyl contents and lower levels of SOD activity compared with AAP patients' or control sera. In conclusion, this is the first study to demonstrate the role of NO-modified-eSOD in AA. Our novel results conclude that perturbations in SOD by NO presenting unique neo-epitopes that might be one of the factors for the antigen driven antibodies induction in AA. Preferential binding of NO-eSOD by AA-IgG pointed out the likely role of NO-eSOD in the initiation/progression of AA.

Oxidative stress and immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by increased platelet destruction or decreased platelet production. The mechanism of the disease has been extensively studied so that we now have a much improved understanding of the pathophysiology; however, the trigger of the autoimmunity remains unclear. More recently, oxidative stress was identified to be involved in the pathogenesis of ITP and provides a new hypothesis for the initiation of autoimmunity in patients with ITP. In this review, oxidative stress and its impact on autoimmunity, particularly ITP, will be covered.

Measurement of malondialdehyde, glutathione, and glutathione peroxidase in SLE patients

Oxidative stress contributes to chronic inflammation of tissues and plays a central role in immunomodulation, which may lead to autoimmune diseases such as systemic lupus erythematosus (SLE) and antiphospholipid syndrome. Markers of oxidative damage include malondialdehyde (MDA), antioxidant scavengers as glutathione (GSH), and glutathione peroxidase (GSH Px), which all correlate well with SLE disease activity. Amelioration of some clinical manifestations of SLE may be expected by targeting lipid peroxidation with dietary or pharmacological antioxidants. Here, we describe the detection of the key players of oxidant/antioxidant imbalance in SLE.

Delivering Oxidation Resistance-1 (OXR1) to Mouse Kidney by Genetic Modified Mesenchymal Stem Cells Exhibited Enhanced Protection against Nephrotoxic Serum Induced Renal Injury and Lupus Nephritis

OBJECTIVE

To elucidate the role of oxidation resistance 1 (OXR1) gene. Oxidative stress plays a pivotal role in pathogenesis of immune-mediated nephritis. Recently we identified oxidation resistance 1 (OXR1) is conventionally expressed in eukaryotes and has an ability to prevent oxidative damage caused by various oxidative stresses. However the protective effect of OXR1 in immune-associated inflammatory response and oxidative damage is not clear and will be investigated in this study.

METHODS

We utilized mesenchymal stem cells (MSCs) as vehicles to carry OXR1 into the injured kidneys of nephritis model mice and investigated the influence of OXR1 on glomerulonephritis. Human OXR1 gene was integrated into genome of MSCs via lentiviral vector, and established hOXR1-MSC cell line which still maintains the differentiation property. 129/svj mice with anti-glomerular basement membrane (GBM) challenge and spontaneous lupus mice B6.Sle1.Sle2.Sle3 were injected with hOXR1-MSCs (i.v. injection) to evaluate the function of hOXR1. Immunohistochemistry was used to appraise the renal pathology and Tunel staining was applied to detect cell apoptosis.

RESULTS

Compared with control mice, hOXR1-MSCs administration showed significantly decreased blood urea nitrogen (BUN), proteinuria and ameliorated renal pathological damage. hOXR1-MSCs transplantation significantly reduced macrophage and T lymphocyte infiltration by inhibiting the expression of CCL2, CCL7, IL-1β, IL-6 and NFκB in mouse kidney. Moreover, hOXR1-MSCs prevented hydrogen peroxide (H₂O₂)-induced oxidative stress and its implantation reduced nitric oxide (NO) in mouse serum and urine to inhibit tubular cell apoptosis.

CONCLUSION

OXR1-MSCs transplantation may exert a certain protective effect on nephritis by suppressing inflammation and oxidative stress.

Immunological studies of reactive oxygen species damaged catalase in patients with systemic lupus erythematosus: correlation with disease activity index

OBJECTIVES

This study was undertaken to investigate the status and contribution of oxidized catalase in systemic lupus erythematosus (SLE) and to explore whether oxidized catalase has a role in disease progression.

METHODS

Catalase (CAT) was modified by reactive oxygen species (ROS). Sera from 50 SLE patients with varying levels of disease activity according to SLE Disease-Activity-Index (SLEDAI) and 45 age- and sex-matched healthy controls were evaluated for antibodies against oxidized CAT.

RESULTS

Serum analysis showed significantly higher level of anti-oxidized-CAT-antibodies in SLE patients compared with controls. Interestingly, not only was there an increased number of subjects positive for anti-oxidized-CAT-antibodies, but also the levels of these antibodies were significantly higher among SLE patients, whose SLEDAI scores were ≥ 10 as compared with lower SLEDAI scores (<10). In addition, significant correlation was observed between the levels of anti-oxidized-CAT-antibodies and SLEDAI score (r = 0.796). Furthermore, sera from SLE patients had lower levels of CAT activity compared with control sera.

CONCLUSIONS

These findings support an association between oxidized CAT and SLE. The stronger response observed in serum samples from patients with higher SLEDAI scores suggests that oxidized CAT may be a useful biomarker in evaluating the progression of SLE and in elucidating the mechanisms of disease pathogenesis.

Relationship between iron metabolism, oxidative stress, and insulin resistance in patients with systemic lupus erythematosus

OBJECTIVE

The aim of the present study was to assess oxidative stress and iron metabolism in systemic lupus erythematosus (SLE) patients with and without insulin resistance (IR).

METHOD

This study included 236 subjects (125 controls and 111 SLE patients). Patients with SLE were divided in two groups: with (n = 72) or without (n = 39) IR.

RESULTS

SLE patients with IR showed higher advanced oxidation protein product (AOPP) levels (p = 0.030) and gamma-glutamyltransferase (GGT) levels (p = 0.001) and lower sulfhydryl groups of proteins (p = 0.0002) and total radical-trapping antioxidant parameter (TRAP) corrected by uric acid (UA) levels (p = 0.04) when compared to SLE patients without IR. However, SLE patients with IR presented lower serum 8-isoprostane (p = 0.05) and carbonyl protein levels (p = 0.04) when compared to SLE patients without IR. Serum ferritin levels were significantly higher in SLE patients (p = 0.0006) than in controls, and SLE patients with IR presented higher serum ferritin levels (p = 0.01) than SLE patients without IR. Patients with SLE showed that IR was inversely correlated to TRAP/UA (r = -0.2724, p = 0.0008) and serum ferritin was positively correlated to AOPP (r = 0.2870, p = 0.004).

CONCLUSIONS

This study found that oxidative stress was higher in the group of SLE patients with IR, and increased ferritin, whether caused by the inflammatory process per se or hyperinsulinaemia, can favour the redox process. In addition, the preset data reinforce the need to measure oxidative stress with several methodologies with different assumptions.

Oxidative stress markers in intestinal mucosa of Tunisian inflammatory bowel disease patients

BACKGROUND / AIMS: Inflammatory bowel diseases (IBDs), Crohn's disease (CrD) and ulcerative colitis (UC), are chronic gastrointestinal inflammatory disorders. The precise etiology of IBD remains unclear, and it is thought that interactions among various factors, including, genetic factors, the host immune system and environmental factors, cause disruption of intestinal homeostasis, leading to dysregulated inflammatory responses of the gut. As inflammation is intimately related to formation of reactive intermediates, including, reactive oxygen species, oxidative stress has been proposed as a mechanism underlying the pathophysiology of IBD. The purpose of this study is to examine the lipid peroxidation, protein oxidation and anti-oxidative profile in Tunisian IBD.

MATERIALS AND METHODS

Malondialdehyde (MDA), conjugated dienes (CD), protein thiol levels, as well as the catalase (CAT) activity were evaluated in intestinal biopsies of 17 patients affected by IBD (12 CrD and 5 UC) and 12 healthy control individuals.

RESULTS

Oxidative stress was confirmed in these two types of disease biopsies as compared to controls. MDA and CD levels were significantly increased in both UC and CrD patients' biopsies as compared to controls' biopsies ( P < 0.001). CAT activity was similar in UC and CrD biopsies' and was not significantly increased in IBD patients' biopsies compared with controls' biopsies ( P > 0.05). Anon-significant decrease in thiol (SH) level was observed in both UC and CrD patients' biopsies compared with controls' biopsies ( P > 0.05).

CONCLUSION

Increased levels of MDA and CD in IBD patients' biopsies underline the implication of oxidative stress in the physiopathology of IBD.

Interaction between glutathione and apoptosis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by imbalance redox state and increased apoptosis. The activation, proliferation and cell death of lymphocytes are dependent on intracellular levels of glutathione and controlled production of reactive oxygen species (ROS). Changes in the intracellular redox environment of cells, through oxygen-derived free radical production known as oxidative stress, have been reported to be critical for cellular immune dysfunction, activation of apoptotic enzymes and apoptosis. The shift in the cellular GSH-to-GSSG redox balance in favor of the oxidized species, GSSG, constitutes an important signal that can decide the fate of the abnormal apoptosis in the disease. The current review will focus on four main areas: (1) general description of oxidative stress markers in SLE, (2) alteration of redox state and complication of disease, (3) role of redox mechanisms in the initiation and execution phases of apoptosis, and (4) intracellular glutathione and its checkpoints with lymphocyte apoptosis which represent novel targets for pharmacological intervention in SLE.

Redox albuminomics: oxidized albumin in human diseases

SIGNIFICANCE

Albumin is the major contributor to colloid oncotic pressure and also serves as an important carrier protein of many endogenous and exogenous molecules throughout the body. In blood and extravascular fluids, albumin is susceptible to different oxidative modifications, especially thiol oxidation and carbonylation. Because of its metal-binding properties and the redox properties of its Cys34 thiol, albumin displays an important antioxidant activity. As albumin is the predominant protein in most body fluids, its Cys34 represents the largest fraction of free thiols within body fluids.

RECENT ADVANCES

Evidence that albumin oxidation takes place in vivo has been reported only recently. Different redox proteomic, mass spectrometric, and chromatographic techniques have shown albumin redox modifications in various human pathophysiological conditions. As a whole, most data here presented demonstrate that massive albumin oxidation occurs in vivo in different biological fluids and, to some extent, that this process is correlated to organ dysfunction.

CRITICAL ISSUES

Recent reports suggest that the albumin redox state may serve as a global biomarker for the redox state in the body in various human diseases. However, further study is required to elucidate the exact relationship between albumin oxidation and pathology. In addition, it is unknown if some albumin oxidized forms may also have diagnostic uses.

FUTURE DIRECTIONS

Application of specific redox proteomics techniques for the characterization of oxidized albumin forms in screening studies is required. A further challenge will be to analyze how these oxidative albumin modifications are related to real impact to the body.

Catalase and lipid peroxidation values in serum of Tunisian patients with pemphigus vulgaris and foliaceus

Pemphigus is an autoimmune disorder resulting from the interaction between autoantibodies and desmoglein. Oxidative stress seems to be responsible for the onset/aggravation of many human diseases. Actually, it is considered as one of the several factors for the etiopathogenesis of pemphigus. The present study aims to evaluate the oxidative state in the sera of pemphigus vulgaris and pemphigus foliaceus patients by assessing lipid peroxidation, proteins oxidation, and antioxidant enzyme activity. This study included 36 pemphigus vulgaris and 42 pemphigus foliaceus patients as well as a group of controls consisting of 78 healthy volunteers. Malondialdehyde levels (p < 0.001) and catalase activity (p < 0.001) are higher in both groups of patients than in the control group. The two groups of patients showed a nonsignificant decrease in the thiol groups compared with the healthy one. A nonsignificant difference was shown between pemphigus vulgaris and pemphigus foliaceus patients, except for the catalase which shows an increase in the pemphigus vulgaris group. We have also found significant correlations between serum oxidative stress marker levels and serum anti-desmoglein antibody levels in the two pemphigus groups. These findings underline the implication of oxidative stress in the physiopathology of pemphigus by the increase in the autoantibodies' reactivity.

Extracellular matrix remodeling: the common denominator in connective tissue diseases. Possibilities for evaluation and current understanding of the matrix as more than a passive architecture, but a key player in tissue failure

Increased attention is paid to the structural components of tissues. These components are mostly collagens and various proteoglycans. Emerging evidence suggests that altered components and noncoded modifications of the matrix may be both initiators and drivers of disease, exemplified by excessive tissue remodeling leading to tissue stiffness, as well as by changes in the signaling potential of both intact matrix and fragments thereof. Although tissue structure until recently was viewed as a simple architecture anchoring cells and proteins, this complex grid may contain essential information enabling the maintenance of the structure and normal functioning of tissue. The aims of this review are to (1) discuss the structural components of the matrix and the relevance of their mutations to the pathology of diseases such as fibrosis and cancer, (2) introduce the possibility that post-translational modifications (PTMs), such as protease cleavage, citrullination, cross-linking, nitrosylation, glycosylation, and isomerization, generated during pathology, may be unique, disease-specific biochemical markers, (3) list and review the range of simple enzyme-linked immunosorbent assays (ELISAs) that have been developed for assessing the extracellular matrix (ECM) and detecting abnormal ECM remodeling, and (4) discuss whether some PTMs are the cause or consequence of disease. New evidence clearly suggests that the ECM at some point in the pathogenesis becomes a driver of disease. These pathological modified ECM proteins may allow insights into complicated pathologies in which the end stage is excessive tissue remodeling, and provide unique and more pathology-specific biochemical markers.

Increased neutrophil oxidative burst metabolism in systemic lupus erythematosus

INTRODUCTION

There is increased frequency of discoid lesions (2.7%) and SLE (0.5%) in patients with chronic granulomatosus disease, but the literature is still controversial about phagocyte oxidative burst in SLE patients.

MATERIALS AND METHODS

300 SLE patients and 301 blood donors were evaluated for quantitation of the oxidative burst in phagocytes by flow cytometry based on the oxidation of 2,7-dichlorofluorescein-diacetate after stimuli with Staphylococcus aureus and Pseudomonas aeruginosa.

RESULTS

Neutrophils from SLE patients displayed higher basal reactive oxygen species (ROS) production than healthy controls [Mean of fluorescence intensity (MFI) = 53.77 ± 11.38 vs 15.08 ± 2.63, p < 0.001] and after stimulation with S. aureus (MFI = 355.46 ± 58.55 vs 151.92 ± 28.25, p < 0.001) or P. aeruginosa (MFI = 82.53 ± 10.1 vs 48.99 ± 6.74, p < 0.001). There was stronger neutrophil response after bacterial stimuli (ΔMFI) in SLE patients than in healthy controls (S. aureus = 301.69 ± 54.42 vs 118.38 ± 26.03, p < 0.001; P. aeruginosa = 28.76 ± 12.3 vs 15.45 ± 5.15, p < 0.001), but no difference with respect to the oxidative burst profile according to disease activity (SLEDAI ≥ 6) or severity (SLICC-DI ≥2). Patients with kidney involvement presented higher basal and stimulated ROS production in neutrophils.

DISCUSSION

The present findings corroborate the important role of innate immunity in SLE and implicate neutrophils in the pathophysiology of the disease.

The relationship between the increased frequency of serum antineuronal antibodies and the severity of autism in children

BACKGROUND

Autism may involve an autoimmune pathogenesis. Immunotherapy may have a role in autistic children who have brain auto-antibodies.

AIM

This study aimed to investigate the frequency of serum antineuronal auto-antibodies, as indicators of the presence of autoimmunity to brain, in a group of autistic children. We are the first to measure the relationship between these antibodies and the degree of the severity of autism.

METHODS

Serum antineuronal antibodies were measured, by indirect immunofluorescence technique, in 80 autistic children, aged between 6 and 12 years, in comparison to 80 healthy-matched children. The severity of autism was assessed by using the Childhood Autism Rating Scale.

RESULTS

Autistic children had significantly higher percent positivity of serum antineuronal antibodies (62.5%) than healthy controls (5%), P<0.001. The frequency of the positivity of serum antineuronal antibodies was significantly higher in children with severe autism (87.5%) than children with mild to moderate autism (25%), P<0.001. Similarly, the frequency of the positivity of these antibodies was significantly higher in female children with autism (90%) than male autistic children (53.3%), P=0.001.

CONCLUSIONS

Serum antineuronal antibodies were found in a subgroup of autistic children and they were significantly correlated to the severity of autism. Thus, autism may be, in part, one of the pediatric autoimmune neuropsychiatric disorders. Further wide-scale studies are warranted to shed light on the etiopathogenic role of antineuronal antibodies in autism. The role of immunotherapy in autistic patients, who are seropositive for antineuronal antibodies, should also be studied.

Oxidative stress in multiple sclerosis patients in clinical remission: association with the expanded disability status scale

Increased levels of oxidative stress markers and/or decreased levels of antioxidant molecules have been described in patients with multiple sclerosis (MS). This imbalance has been implicated in demyelination and axonal damage. The aims of this study were to evaluate oxidative stress in MS patients and to verify its correlation with disability as assessed by the expanded disability status scale (EDSS). This case-controlled study included 91 patients with relapsing-remitting multiple sclerosis (RR-MS) and 196 healthy individuals matched by age, gender, ethnicity, smoking status, and body mass index. Oxidative stress was evaluated by tert-butyl hydroperoxide-initiated chemiluminescence (CL-LOOH), carbonyl protein, nitric oxide metabolites (NOx), total radical-trapping antioxidant parameter (TRAP), sulfhydryl groups of proteins and serum uric acid levels. MS patients exhibited higher plasma levels of CL-LOOH (p<0.0001) and carbonyl protein (p=0.0081), and lower plasma levels of NOx (p<0.0001), TRAP (p=0.0088), and sulfhydryl groups (p=0.0003) compared to the control subjects. A multivariate analysis showed an association between oxidative markers and the presence of MS. Patients with an EDSS >3.5 showed higher CL-LOOH than control subjects (p=0.0093). A positive correlation was observed between CL-LOOH and EDSS (r=0.3244, p=0.0026) and between carbonyl protein and EDSS (r=0.3012, p=0.0041). These results demonstrate that oxidative stress plays an important role in the physiopathology of MS progression.

Biomarkers of oxidative stress in epidermis of Tunisian pemphigus foliaceus patients

BACKGROUND

Reactive oxygen species play a key role in the development of many dermatological disorders.

OBJECTIVE

The purpose of this study is to examine the lipid peroxidation, protein oxidation and antioxidative profile in Tunisian pemphigus foliaceus (PF) patients.

METHODS

Malondialdehyde (MDA), conjugated dienes (CD), protein thiol levels, catalase (CAT) and superoxide dismutase (SOD) activities were evaluated in skin biopsies of 13 patients compared to biopsies of 7 healthy controls.

RESULTS

Oxidative stress was confirmed in these three types of patient biopsies as compared to controls. Thus, MDA, CD levels and catalase CAT and SOD activities were significantly increased in lesional, perilesional and normal biopsies of PF patients than in those of control subjects. Protein oxidative was confirmed by lower levels of protein thiols in lesional, perilesional and normal biopsies than in control's biopsies. Otherwise, in patients, a significant rise of these biomarkers was observed in lesional and perilesional biopsies compared with normal biopsies.

CONCLUSION

This study shows that oxidative stress could be involved in the pathogenesis of PF by the spread of skin lesions and/or by the increase in auto-antibodies' reactivity.

A lack of association between elevated serum levels of S100B protein and autoimmunity in autistic children

BACKGROUND

S100B is a calcium-binding protein that is produced primarily by astrocytes. Increased serum S100B protein levels reflect neurological damage. Autoimmunity may have a role in the pathogenesis of autism in some patients. Autoantibodies may cross the blood-brain barrier and combine with brain tissue antigens, forming immune complexes and resulting in neurological damage. We are the first to investigate the relationship between serum levels of S100B protein, a marker of neuronal damage, and antiribosomal P protein antibodies in autistic children.

METHODS

Serum S100B protein and antiribosomal P antibodies were measured in 64 autistic children in comparison to 46 matched healthy children.

RESULTS

Autistic children had significantly higher serum S100B protein levels than healthy controls (P < 0.001). Children with severe autism had significantly higher serum S100B protein than patients with mild to moderate autism (P = 0.01). Increased serum levels of antiribosomal P antibodies were found in 40.6% of autistic children. There were no significant correlations between serum levels of S100B protein and antiribosomal P antibodies (P = 0.29).

CONCLUSIONS

S100B protein levels were elevated in autistic children and significantly correlated to autistic severity. This may indicate the presence of an underlying neuropathological condition in autistic patients. Antiribosomal P antibodies may not be a possible contributing factor to the elevated serum levels of S100B protein in some autistic children. However, further research is warranted to investigate the possible link between serum S100B protein levels and other autoantibodies, which are possible indicators of autoimmunity to central nervous system in autism.

Oxidative stress-induced antibodies to carbonyl-modified protein correlate with severity of chronic obstructive pulmonary disease

RATIONALE

There is increasing evidence for the presence of autoantibodies in chronic obstructive pulmonary disease (COPD). Chronic oxidative stress is an essential component in COPD pathogenesis and can lead to increased levels of highly reactive carbonyls in the lung, which could result in the formation of highly immunogenic carbonyl adducts on "self" proteins.

OBJECTIVES

To determine the presence of autoantibodies to carbonyl-modified protein in patients with COPD and in a murine model of chronic ozone exposure. To assess the extent of activated immune responses toward carbonyl-modified proteins.

METHODS

Blood and peripheral lung were taken from patients with COPD, age-matched smokers, and nonsmokers with normal lung function, as well as patients with severe persistent asthma. Mice were exposed to ambient air or ozone for 6 weeks. Antibody titers were measured by ELISA, activated compliment deposition by immunohistochemistry, and cellular activation by ELISA and fluorescence-activated cell sorter.

MEASUREMENTS AND MAIN RESULTS

Antibody titer against carbonyl-modified self-protein was significantly increased in patients with Global Initiative for Chronic Obstructive Lung Disease stage III COPD compared with control subjects. Antibody levels inversely correlated with disease severity and showed a prevalence toward an IgG1 isotype. Deposition of activated complement in the vessels of COPD lung as well as autoantibodies against endothelial cells were also observed. Ozone-exposed mice similarly exhibited increased antibody titers to carbonyl-modified protein, as well as activated antigen-presenting cells in lung tissue and splenocytes sensitized to activation by carbonyl-modified protein.

CONCLUSIONS

Carbonyl-modified proteins, arising as a result of oxidative stress, promote antibody production, providing a link by which oxidative stress could drive an autoimmune response in COPD.

Post-translational modifications of the extracellular matrix are key events in cancer progression: opportunities for biochemical marker development

The aim of this review is to discuss the potential usefulness of a novel class of biochemical markers, designated neoepitopes. Neoepitopes are post-translational modifications (PTMs) of proteins and are derived by processes, such as protease cleavage, citrullination, nitrosylation, glycosylation and isomerization. Each PTM results from a specific local physiological or pathobiological process. Identification of each modification to a tissue-specific protein may reveal a unique disease-specific biochemical marker. During cancer metastasis, the host tissue is extensively degraded and replaced by cancer-associated extracellular matrix (ECM) proteins. Furthermore, severe cellular stress and inflammation, caused by cancer, results in generation of PTMs, which will be distributed throughout the ECM. This gives rise to release of protein-specific fragments to the circulation. Here we highlight the importance of remodeling of the ECM in cancer and the generation of PTMs, which may be cancer specific and reflect disease progression; thus having potential for biochemical marker development.

Oxidative stress is associated with liver damage, inflammatory status, and corticosteroid therapy in patients with systemic lupus erythematosus

Oxidative stress exerts an important role on the pathophysiological mechanisms of systemic lupus erythematosus (SLE). This study investigated oxidative stress in patients with SLE and its correlation with disease activity, corticosteroid therapy, and liver function biomarkers. The study included 58 patients with SLE and 105 healthy volunteers. Patients showed oxidative stress increase evaluated by tert-butyl hydroperoxide-initiated chemiluminescence (CL-LOOH), advanced oxidation protein products (AOPP), and nitric oxide metabolites. C-reactive protein (CRP) was associated with CL-LOOH and with AOPP. Aspartate aminotransferase correlated significantly with CL-LOOH and with AOPP. Patients with disease activity showed an inverse significant correlation of daily prednisone doses and CL-LOOH and a direct correlation with total antioxidant capacity. In conclusion, patients with SLE have persistent lipoperoxidation and protein oxidation even with inactive disease or mild disease activity. The significant correlation between oxidative stress and CRP suggests that, despite clinical remission, the persistence of an inflammatory condition favors oxidative stress. Oxidative stress was associated with liver enzymes, and this relationship seems to support the hypothesis of drug-induced oxidative stress with consequent liver injury. In relation to non-active disease, patients with active SLE did not present oxidative stress and antioxidant capacity changes, due to the antioxidant drugs used in SLE treatment, especially prednisone.

Molecular pathophysiology of the antiphospholipid syndrome: the role of oxidative post-translational modification of beta 2 glycoprotein I

It has been well established that antiphospholipid antibodies and specifically those directed against beta 2 glycoprotein I (β2GPI) are pathogenic for the development of thrombosis in the antiphospholipid syndrome (APS). Several groups have shown that anti-β2GPI antibodies, in complex with β2GPI, elicit effects on blood cells and coagulation-fibrinolysis proteins, which prime the arterial and venous vasculature for the development of thrombosis. However, much less is known about the mechanism initiating the production of autoantibodies against β2GPI, a physiological abundant protein of blood. In the current review, novel findings are presented regarding the structure and oxidative post-translational modifications of β2GPI, which trigger the immune response. The majority of circulating β2GPI exists in a form containing unpaired cysteines (free thiols), which constitutes the reduced form of β2GPI. The free thiols exposed on β2GPI are involved in the interaction with platelets and endothelial cells. We propose that this abundant pool of free thiols may serve as an antioxidant reservoir protecting cells or critical molecules from oxidative stress. Oxidation of β2GPI confers an increase in its immunogenicity through a Th1 immunological mechanism. The clinical significance of these observations is that serum from patients with APS, assessed by a novel ELISA assay, have a significant increase in oxidised β2GPI. These findings hold promise, not only for the delineation of the role of β2GPI as an immunological target, but also for the development of improved diagnostic and prognostic assays for APS.

Hydroxyl radical modification of immunoglobulin g generated cross-reactive antibodies: its potential role in systemic lupus erythematosus

Objective:

Role of reactive oxygen species (ROS) modified human Immunoglobulin G (IgG) in systemic lupus erythematosus (SLE) has been investigated.

Methods:

Human IgG was modified by hydroxyl-radicals. Immunogenicity of native and modified human IgG was probed by inducing polyclonal antibodies in rabbits. Cross-reactions of induced antibodies with nucleic acid, chromatin, different blood proteins and their ROS modified conformers were determined by competitive inhibition ELISA. The binding characteristics of circulating autoantibodies in SLE patients (n = 72) against native and modified IgG were screened by direct binding and competition ELISA and the results were compared with healthy age-matched controls (n = 39).

Results:

Induced antibodies against ROS-modified human IgG exhibited diverse antigen binding characteristics. Native DNA, native chromatin and their ROS-modified conformers were found to be effective inhibitors of induced antibody-immunogen interaction. Induced antibodies against native human IgG showed negligible binding to the above mentioned nucleic acid antigens. SLE sera (48.6%) showed strong binding to ROS-human IgG in comparison with its native analogue (P < 0.01). Normal human sera (NHS) showed negligible binding with either antigen (P > 0.05).

Conclusion:

ROS-induced modifications in human IgG present neo-epitopes, and make it a potential immunogen. The induced antibodies against ROS-modified human IgG resembled the diverse antigen-binding characteristics of naturally occurring SLE anti-DNA autoantibodies. ROS-modified IgG may be one of the factors for the induction of circulating SLE autoantibodies.

Enhanced reactivity to malondialdehyde-modified proteins by systemic lupus erythematosus autoantibodies

OBJECTIVE

Evaluation of the reactivity of autoantibodies of systemic lupus erythematosus (SLE) patients directed against malondialdehyde (MDA)-modified catalase, superoxide dismutase (SOD), and different Hep2 protein fractions (hydrophobic, hydrophilic, and nuclear).

METHOD

Thiol groups and MDA-protein adducts were first assessed among 65 SLE patients and 60 healthy controls. Then, the reactivities of SLE immunoglobulin (Ig)G autoantibodies towards MDA-modified and unmodified proteins were compared using a standard enzyme-linked immunosorbent assay (ELISA).

RESULTS

An increase in the levels of MDA-modified proteins and a decrease in the concentration of thiol groups among SLE patients (p < 0.05) were observed. IgG circulating autoantibodies in the sera of SLE patients exhibited a significant enhanced reactivity (p < 0.05) against catalase and SOD-modified proteins. The same data were observed in the different protein fractions extracted from cultured cells (p < 0.05).

CONCLUSION

These data reinforce the role of oxidative stress and especially lipid peroxidation products in the progression of SLE disease.

Evidence for chronically elevated serum protein oxidation in systemic lupus erythematosus patients

Serum protein oxidation levels in people with the autoimmune disease systemic lupus erythematosus (SLE) have previously been shown to (a) be elevated at a single time point and (b) correlate with disease activity. This study investigates whether this elevation is a chronic phenomenon, by analysis of multiple serum samples collected from 21 SLE patients and nine controls over a period of up to 38 months. Protein thiols were chronically decreased in SLE patients with stable or variable disease activity compared to controls, whilst protein-bound carbonyls and glycine were chronically increased. 2D-gel analysis of carbonyl distribution showed albumin and immunoglobulins to be particularly affected. In SLE patients with stable disease activity, higher long-term protein oxidation correlated with higher long-term disease activity. SLE patients with variable disease activity exhibited varying correlations between protein oxidation and disease activity markers. These results further support a role for oxidative stress in the pathogenesis of SLE.

De novo autoimmunity after organ transplantation: targets and possible pathways

The development of autoantibodies to different tissue-specific antigens in patients without existing history of autoimmune diseases suggests that autoimmunity may develop de novo after organ transplantation. In addition to allo-specific immune responses, tissue-specific autoimmunity also appears contribute to the host anti-graft response, and thus may affect long-term graft function. As graft failure caused by chronic rejection is a major challenge in clinical transplantation, understanding de novo autoreactivity after transplantation has important ramifications. This review investigates this emerging concept by discussing target antigens and possible pathways.