Saloua Lassoued

Increased levels of autoantibodies against catalase and superoxide dismutase associated with oxidative stress in patients with rheumatoid arthritis and systemic lupus erythematosus

Objective: To evaluate the level of autoantibodies against superoxide dismutase (SOD) and catalase (CAT) in the sera of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) Tunisian patients, to study the oxidative profile among the same patients and to establish a correlation between the two parameters in order to understand the role of each one in the genesis of the two diseases. Method: Using a standard enzyme‐linked immunosorbent assay (ELISA), the levels of immunoglobulin G (IgG) and IgM directed against CAT and SOD in the sera of 39 RA patients, 40 SLE patients, and 50 control healthy individuals were evaluated. The oxidative/antioxidative profile was tested by measuring serum malondialdehyde (MDA), conjugated dienes (CD), CAT activity, and SOD activity. Results: Our data showed increased levels of IgG antibodies (Ab) against CAT in both groups of patients (p<0.05) compared to control subjects. However, the SLE patients displayed an increased level of anti‐SOD IgG (p<0.05). In all patients the lipid peroxidation was confirmed by high levels of MDA and conjugated dienes (p<0.05). RA patients exhibited an increasing CAT and SOD activity in their sera (p<0.05) with a positive correlation observed between CAT and IgG anti‐CAT (p<0.05). The same results were observed for SLE patients. In addition, a positive correlation was observed between anti‐CAT Ab and anti‐SOD Ab in SLE patients (p<0.05). Conclusion: Collectively, these results suggested that the primary factor causing the oxidative stress observed in RA and SLE is excessive free radical production rather than impaired CAT or SOD activity due to autoantibody inhibition.

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.

A new Lactobacillus plantarum strain, TN8, from the gastro intestinal tract of poultry induces high cytokine production.

This study aimed to determine the probiotic potential of 100 strains of Lactic Acid Bacteria (LAB) isolated from different intestinal segments of indigenous poultry in Tunisia. The strains were submitted to a battery of standard tests and criteria commonly used for determining their probiotic properties and attributes. The findings revealed that 19 of the isolates exhibited antimicrobial activity against 4 pathogenic bacteria, and that 4 (TN1, TN8, TN7, and TN13) showed good resistance to pH 3 and 5% bovine bile. Three isolates, namely TN1, TN8, and TN13, showed sensitivity to several antibiotics and were, therefore, selected for further enzymatic activity assays. Two isolates, namely TN1 and TN8, showed high efficacy of adhesion to chicken enterocytes. The cytokines released after stimulation by the two isolates showed high anti-inflammatory profiles, with an increased rate of Interleukin-10 (IL-10) production for the TN8 strain. Showing the highest performance, TN8 was submitted to 16S rRNA gene sequencing, which revealed that the strain was of the species Lactobacillus plantarum. Overall, the findings indicate that the Lactobacilli from poultry intestine has a number of promising properties that make it candidate for application as a probiotic additive in poultry industry.

A Comparative Study of the Oxidative Profile in Graves’ Disease, Hashimoto’s Thyroiditis, and Papillary Thyroid Cancer

The aim of this study was to evaluate and compare the oxidative profiles of three thyroid disorders: Graves’ disease (GD), Hashimoto thyroiditis (HT), and papillary thyroid cancer (PTC). Malondialdehyde levels (MDA), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities were examined in the plasma of 52 patients (29 untreated HT, 16 untreated GD, and 7 PTC who underwent surgical therapy). Results were compared with those of 30 healthy controls and among the three groups of patients. The GD, HT, and PTC patients exhibited increased plasma MDA levels and SOD activities compared with the controls (p < 0.05, p < 0.05, and p < 0.001, respectively). CAT activities significantly increased only for the PTC and HT patients (p < 0.001 and p < 0.05, respectively), whereas GPx activities significantly decreased only in the GD and PTC (p < 0.05 and p < 0.01, respectively). The comparison among the three groups of patients has shown increased MDA level and SOD activity for the PTC patients as compared to the GD patients (p < 0.01 and p < 0.001, respectively). Compared with HT, PTC patients exhibited significant higher MDA level, SOD, and CAT activities and a significant lower GPx activity (p < 0.01, p < 0.001, p < 0.05, and p < 0.05, respectively). No significant discrepancies were noted between the GD and HT patients. Our results have clearly shown an oxidative profile that is highly disturbed for the PTC patients as compared to those of autoimmune disorders. Future studies are needed to determine whether or not the oxidative stress has a prognostic value in this pathology.

Protective effect of quercetin against oxidative stress caused by dimethoate in human peripheral blood lymphocytes

BackgroundThe aim of this study is to investigate the effect of quercetin in alleviating the cytotoxic effects of Dimethoate in human peripheral blood lymphocytes.MethodsLymphocytes were divided into too groups. The first group, lymphocytes were incubated for 4 h at 37°C with different concentrations (0, 40, 60 and 100 mM) of Dimethoate. The second group was preincubated with quercetin for 30 min and followed by Dim incubation for 4 h at 37°C.ResultsFollowing in vitro incubation, Dimethoate caused a significant increase in malondialdehyde levels, a significant decrease in thiol levels, as well as a significant increase in superoxide dismutase, and catalase activities in lymphocytes at different concentrations. Quercetin pretreated lymphocytes showed a significant protection against the cytotoxic effects inducted by Dimethoate on the studied parameters.ConclusionIn conclusion, antioxidant quercetin could protect against Dimethoate-induced oxidative stress by decreasing lipid peroxidation, protein oxidation and increasing superoxide dismutase and catalase activities in human lymphocytes.

Oxidative Stress Markers in Intestinal Mucosa of Tunisian Inflammatory Bowel Disease Patients

Background/Aims: Inflammatory bowel diseases (IBDs), Crohns 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.

Lipid Peroxidation and Antioxidant System in the Tumor and in the Blood of Patients with Nasopharyngeal Carcinoma

Reactive oxygen species play a key role in cancer development by inducing and maintaining the oncogenic phenotypes of cancer cells. In this study, we examined lipid peroxidation and antioxidant enzymes activities in the blood and in the tumor of nasopharyngeal carcinoma patients. Plasma malondialdehyde, conjugated dienes, erythrocytes catalase, and superoxide dismutase activities have been measured in 30 untreated nasopharyngeal carcinoma patients and 30 controls on one hand. On the other hand, tumor malondialdehyde level, catalase, and superoxide dismutase activities have been measured in five nasopharyngeal carcinoma patients and compared with four controls. The lipid peroxidation was confirmed in the plasma by the high levels of malondialdehyde and conjugated dienes (p < 0.001, respectively). Additionally, significantly higher concentrations of malondialdehyde were found in biopsies compared to the control group (p < 0.001). In erythrocytes, superoxide dismutase activity was higher in patients than in controls (p < 0.05), while it was unchanged in the tumor (p > 0.05). Both erythrocytes and tumor catalase activities were significantly lower in patients than in controls (p < 0.001, respectively). Statistical studies have shown a positive correlation between malondialdehyde level and IgA antibodies level against Epstein–Barr virus capsid antigen (p < 0.05). In conclusion, we reported the presence of an oxidative stress in the blood and in the biopsies of nasopharyngeal carcinoma patients where Epstein–Barr virus seems to play a role.

Antioxidant activity of ethanolic extract of inflorescence of Ormenis Africana in vitro and in cell cultures.

BackgroundThe antioxidant potency of the hydroethanolic extract of Ormenis Africana (HEOA), Asteraceae was evaluated with regards to total polyphenol, flavonoid and anthocyanins content. Antioxidant activity has been assessed chemically and biologically. First, the free radical scavenging ability of HEOA was evaluated using two commonly in vitro tests: ABTS and DPPH radicals. Then, the protection effect of this extract against oxidative stress was conducted in HeLa cells treated with Fe2+ or H2O2. Oxidative stress was evaluated by measuring the lipid peroxidation levels (TBARs and DC) and the antioxidant enzymes activities (catalase and Superoxide dismutase). Cytotoxic effect of HEOA was prealably determined against HeLa cell line by MTT assay.ResultsHEOA contain considerable levels of antioxidant compound as evidenced by high amount of polyphenols (312.07 mg GAE/g dray matter), flavonoids (73.72 ± 1.98 mg QE/g dray matterl) and anthocyanins (0.28 ± 0.09 mg Cy-3-glu E/g dray matter). DPPH and ABTS assays showed a high antioxidant activity (IC50 = 24 μg/ml; TEAC = 2.137 mM) which was comparable to BHT.In biological system, HEOA exhibited a 50% cytotoxic concentration evaluated as 16.52 μg/ml. Incubation of HeLa cell line with no cytotoxic concentrations resulted in a remarkable protection from oxidative stress induced by Fe2+ or H2O2 which was evidenced by a decrease of MDA and CD levels as well as a diminution of antioxidant enzymes activities (Catalase and SOD) as compared to cells treated with Fe2+ or H2O2 alone.ConclusionThe hydroethanolic extract of O. Africana could thus be considered as a source of potential antioxidants. The results of this study will promote the reasonable usage of this plant in food and pharmacy industries as well as in alternative medicine and natural therapy.

Phenolic contents and antioxidant activity of ethanolic extract of Capparis spinosa

Caper plant (Capparis spinosa) extracts have been associated with diverse biological activities including anti-oxidant properties. In this work, we characterized the hydro-ethanolic extract obtained from C. spinosa leaves [hydroethanolic extract of C. spinosa (HECS)] by analyzing the content in anti-oxidant compounds such as polyphenols, flavonoids and anthocyanins. Further, we evaluated HECS antioxidant activities in vitro using bleaching of 1,1-diphenyl-2-picrylhydrazyl radical and ABTS test as well as by pretreatment of HeLa cells exposed to Fe2+ or H2O2. Our findings indicate that HECS contains high amount of total phenolic compounds and high levels of flavonoids and anthocyanins. Furthermore, HECS exhibited antioxidant activity in both chemical and biological tests. Specially, pretreatment of HeLa cells with different concentrations of the extract conferred protection against lipid peroxidation and modulated activities of two antioxidant enzymes, SOD and catalase. These results revealed HECS antioxidant effects and suggest that C. spinosa leaves are a potential source of natural antioxidant molecules with possible applications in industry and medicine.

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.