Immunomodulatory effect of vitamin D supplementation on Behçet's disease patients: effect on nitric oxide and Th17/Treg cytokines production.

INTRODUCTION: In the last decade, an immuno-modulatory effect of vitamin D supplementation have emerged as a potential therapeutic approach for some inflammatory and autoimmune diseases. As previously reported, vitamin D deficiency was strongly linked to several diseases as Behçet's disease (BD). BD is a chronic systemic inflammatory disorder with autoimmunity, genetic and environmental factors involvement. The aim of our current study is to set up a new therapeutic strategy in BD, combining conventional therapy and vitamin D supplementation. MATERIALS AND METHODS: Blood samples were collected from active and inactive BD patients and healthy controls (HC) to evaluate 25(OH) vitamin D levels using an electrochemiluminescence method. All deficient and insufficient vitamin D BD patients' were supplemented with vitamin D3 (CHOLECALCIFEROL, 200 000 UI/1 ml). In this context, NO, IL-17A and IL-10 levels were evaluated in patients and HC in vivo and ex vivo using Griess and ELISA methods respectively. RESULTS: Before supplementation, we noted with interest that BD patients had vitamin D deficiency, associated with elevated in vivo and ex vivo NO and IL-17A levels compared to HC. Conversely, low IL-10 levels were observed in the same BD patients in comparison to HC. Interestingly, restored vitamin D status in supplemented BD patients was related to the decreased NO levels. In the same way, the IL-10/IL-17A ratio was improved. CONCLUSIONS: Collectively, our data suggest that vitamin D supplementation in combination with conventional treatments has a beneficial effect and could constitute a good therapeutic candidate for alleviating inflammatory responses during Behçet disease.

Auto-immunity profile evaluation during different clinical manifestations of Behçet disease in Algerian patients: effect of corticosteroid treatment.

BACKGROUND AND AIMS: Behçet disease (BD) is a chronic multisystem disease. It stands at the crossroads between the auto-immunity and auto-inflammatory disorders. Our study aims to evaluate corticosteroids therapy effects on serum immunoglobulin isotypes and anti-phospholipid auto-anti-body production in Algerian BD patients with different clinical manifestations. METHODS: We evaluated serum immunoglobulin isotypes and anti-phospholipid (anti-cardiolipin, anti-ß2glycoprotein I, anti-prothrombin) auto-anti-body production using Turbidimetric or Luminex platform assays. Our study was conducted in naïve active BD patients and in corticosteroid-treated patients with different clinical manifestations. RESULTS AND DISCUSSION: Our results indicate that IgM, IgG, and IgA levels were higher in naïve active patients. The increase in sera isotypes did not differ according to the clinical manifestation, except for IgA production, which was associated with an increased risk of mucocutaneous and ocular involvement. Interestingly, in corticosteroid-treated active patients, no difference was reported between each clinical subgroup. Furthermore,anti-cardiolipin, anti-ß2glycoprotein I and anti-prothrombin auto-anti-body levels were elevated in naïve active patients. Contrary to anti-prothrombin, high anti-cardiolipin and anti-ß2glycoprotein I, production differed according to the clinical manifestations and was associated with an increased risk of mucocutaneous and ocular involvement. Importantly, corticosteroid therapy significantly reduced these immune markers regardless of the clinical manifestations. CONCLUSION: Our results suggest that high IgA production could be a risk marker of uveitis in naïve active patients. Moreover, concomitant high anti-cardiolipin, anti-ß2glycoprotein I and anti-prothrombin production is related to an increased risk of mucocutaneous lesions, ocular and vascular involvement. Collectively, our data indicate the importance of evaluating the corticosteroid effect on immune responses associated with BD to ensure an adequate investigation of each related clinical manifestation.

Propolis modulates NOS2/arginase-1 pathway in tropomyosin-induced experimental autoimmune uveitis.

In this study, we evaluated the preventive and curative effects of ethanolic extract of Propolis (EEP) during α-Tropomyosin-induced uveitis in an experimental model using Wistar rats, through the regulation of inducible nitric oxide synthase (NOS2) and arginase-1. In this context, rats received daily injection of EEP (100 mg/kg) for 5 days prior to immunization or for 9 days commencing 5 days post immunization with α-Tropomyosin extract, then were sacrificed at day 14. Histological examination, NOS2, arginase-1, and nuclear factor-κB (NF-κB) expression were evaluated in the retinas. Plasmatic production of nitric oxide (NO), urea, IL-4, and TNF-α was assessed. We have found that treatment with EEP substantially reduced the retinal histological damages induced by α-Tropomyosin. In the same context, a significant decrease of NO and TNF-α levels was noticed. Interestingly, EEP down-modulated NOS2 and NF-κB expression in retina. Also, an increase in urea and IL-4 levels was concomitant to an up-modulation of arginase-1 expression. Hence, it appears that EEP attenuated retinal damages through the induction of Th2 response and the inhibition of NF-κB/NOS2 pathway.

Ex vivo immunomodulatory effect of ethanolic extract of propolis during Celiac Disease: involvement of nitric oxide pathway.

Celiac Disease (CeD) is a chronic immune-mediated enteropathy, in which dietary gluten induces an inflammatory reaction, predominantly in the duodenum. Propolis is a resinous hive product, collected by honeybees from various plant sources. Propolis is well-known for its anti-inflammatory, anti-oxidant and immunomodulatory effects, due to its major compounds, polyphenols and flavonoids. The aim of our study was to assess the ex vivo effect of ethanolic extract of propolis (EEP) upon the activity and expression of iNOS, along with IFN-γ and IL-10 production in Algerian Celiac patients. In this context, PBMCs isolated from peripheral blood of Celiac patients and healthy controls were cultured with different concentrations of EEP. NO production was measured using the Griess method, whereas quantitation of IFN-γ and IL-10 levels was performed by ELISA. Inducible nitric oxide synthase (iNOS) expression, NFκB and pSTAT-3 activity were analyzed by immunofluorescence assay. Our results showed that PBMCs from Celiac patients produced high levels of NO and IFN-γ compared with healthy controls (HC). Interestingly, EEP reduced significantly, NO and IFN-γ levels and significantly increased IL-10 levels at a concentration of 50 µg/mL. Importantly, EEP downmodulated the iNOS expression as well as the activity of NFκB and pSTAT-3 transcription factors. Altogether, our results highlight the immunomodulatory effect of propolis on NO pathway and on pro-inflammatory cytokines. Therefore, we suggest that propolis may constitute a potential candidate to modulate inflammation during Celiac Disease and has a potential therapeutic value.

Influence of corticosteroid therapy on IL-18 and nitric oxide production during Behçet's disease.

BACKGROUND AND AIMS: Behçet's disease (BD) is a chronic multisystemic inflammatory disease with complex etiopathogenesis. Th1-proinflammatory cytokines seem to be involved in its pathogenesis. Our current study aims to evaluate interleukin-18 (IL-18) and nitric oxide (NO) involvement in the development of different clinical manifestations of BD as well as to investigate the corticosteroid therapy effect on this production in Algerian patients. METHODS: For this purpose, we evaluated in vivo and ex vivo IL-18, interferon-γ (IFN-γ) levels using ELISA and NO production by the Griess' method in naïve-active and corticosteroid-treated BD patients with different clinical manifestations. Additionally, we assessed CD40/CD40L expression by flow cytometrics assay in these groups of patients. RESULTS AND DISCUSSION: Our results indicate that IL-18 and nitrite levels were higher in naïve-active BD patients. Interestingly, this high production differed according to the clinical manifestations and was associated with an increased risk of mucocutaneous and vascular involvement. Concerning corticosteroid treated-active BD patients, no difference was observed in this production between each clinical subgroup. However, IFN-γ levels increased in all categories of active patients. Interestingly, corticosteroid therapy reduced significantly these inflammatory mediators regardless of the clinical manifestations studied. In addition, the CD40/CD40L expression differed according to the clinical presentations. CONCLUSION: Collectively, our results suggest that concomitant high production of IL-18 and NO in naïve-active BD patients is related to an increased risk of mucocutaneous lesions and vascular involvement. Moreover, the relationship between these two inflammatory markers could constitute a predictable tool of BD clinical presentations and an early factor of therapy efficiency.

Vitamin D status in Algerian Behçet's disease patients: an immunomodulatory effect on NO pathway.

Behçet's disease (BD) is an inflammatory multisystemic disorder associated with orogenital ulcers, uveitis and skin lesions with unpredictable episodes of exacerbations and remissions. Even though several immunological and environmental factors contribute to BD progression, its ethiopathogenesis remains uncertain and elusive. Considered as one of the potent environmental factors that can increase prevalence of some autoimmune and inflammatory disorders, vitamin D deficiency has been linked to several diseases as BD. The aim of this study is to assess vitamin D status in Algerian BD patients and its relationship with disease activity. Immunomodulatory effect of this vitamin on nitric oxide (NO), inflammatory mediator, was also undertaken. Serum 25(OH) vitamin D levels were measured in healthy controls (HC), active and inactive BD patients with an electrochemiluminescence method. After treatment of HCs' and patients' peripheral blood mononuclear cells with different concentrations of vitamin D3, NO production was evaluated with Griess method, while inducible nitric oxide synthase (iNOS) and NF-κB expression with immunofluorescence test. A high decrease of vitamin D levels was noted in active BD patients compared to those of inactive stage and HC. However, a higher NO production was observed during active stage of BD compared to inactive one. In inactive BD, vitamin D levels correlates negatively with NO. Interestingly, vitamin D3 inhibits ex vivo NO production, iNOS and NF-κB expression in BD patients. In conclusion, vitamin D deficiency was associated with active BD. This vitamin down-modulates NO production in BD patients, suggesting that it may be considered as promising therapy modulating inflammation during BD.

Ex vivo all-trans retinoic acid modulates NO production and regulates IL-6 effect during rheumatoid arthritis: a study in Algerian patients.

Rheumatoid arthritis (RA) is a chronic autoimmune disease. The pathophysiology of RA implicates several mediators such as nitric oxide (NO) and cytokines such as interleukin-6 (IL-6), which is deeply involved in the main characteristics of RA. Furthermore, all-trans retinoic acid (ATRA) is an active vitamin A derivative well-known to have diverse immunomodulatory actions. In our study, we investigated first, the ex vivo immunomodulatory potential of ATRA on NO pathway by peripheral blood mononuclear cells (PBMCs) from Algerian RA patients. Then, we assessed the possible regulatory effect of ATRA on NO production induced by IL-6. PBMCs isolated from active and inactive RA patients and healthy controls were cultured with different concentrations of IL-6 or/with ATRA. NO production was assessed using the Griess method. Inducible nitric oxide synthase expression and NF-κB activity were analyzed by immunofluorescence test. Our results revealed a high NO production during active RA. We noticed that while IL-6 induced a high NO production and iNOS expression, ATRA downregulated both. ATRA also inhibited nuclear NF-κB translocation. Interestingly, it seems that NO production mediated by IL-6 on PBMCs of RA patients is downregulated by ATRA. Taken together, our results highlight the immunomodulatory effect of ATRA on NO pathway in RA patients and its possible role in regulating IL-6-mediated NO production. All these findings suggest its potential therapeutic role during RA.

Cytokines Modulate the "Immune-Metabolism" Interactions during Behçet Disease: Effect on Arginine Metabolism.

Aim and Methods. In this study, we evaluated NOS and arginase activities and their regulation during Behçet disease, a systemic chronic inflammatory disorder with uncertain etiology. The peripheral blood mononuclear cells of 36 patients and 15 control samples (PBMC) were cultured in either RPMI 1640, MEM, or DMEM complemented with 10% of FBS and antibiotics. Cultures were performed with or without the control or patients plasma. Subsequent treatment contained anticytokines (IL-6, TGF-ß), a mitogenic effector (PHA), or NOS modulators (L-NMMA, BH4). Culture supernatants were harvested after 24 h of incubation. NO and urea measurements were, respectively, performed by modified Griess and Berthelot methods. Results. Higher urea levels were found in patients' plasma compared to the control's (P < 0.05). NOS modulators induced inverted production profiles for NO and urea (P < 0.05). Their results differed depending on the clinical findings (P < 0.05). It was also found that cytokine neutralization induced different response profiles in patients as opposed to control cultures (P < 0.05). Conclusion. Our results suggest that arginases can compete with NOS2 for L-arginine during Behçet disease. Both enzymes are regulated by environmental cytokines and substrate availability. Furthermore, it seems that NOS/arginase balance is dependent on clinical expression.

Ex vivo immunomodulatory effect of all-trans-retinoic acid during Behçet's disease: a study in Algerian patients.

Uveitis, recurrent oral and genital ulcerations associated with skin lesions are the major symptoms of a chronic multisystemic inflammatory disorder known as Behçet's disease (BD). High prevalence of this dreaded disease has been observed in the Mediterranean basin, including Algeria and along the Silk Road. Although the etiologic agent of this disease remains uncertain, many hypotheses have been advanced in its pathogenesis. Our team has previously reported high levels of nitric oxide (NO) in sera of BD patients, suggesting its deleterious effect during chronic inflammation. In our current study, the aim is to investigate the ex vivo immunomodulatory effect of all-trans-retinoic acid (ATRA) on NO pathway in Algerian BD patients. First, peripheral blood mononuclear cells isolated from active and inactive BD patients and healthy controls were cultured with different concentrations of ATRA. NO production was estimated with the Griess method. To elucidate the underlying mechanisms of ATRA effect on NO production, we analyze inducible nitric oxide synthase expression and nuclear factor-κB (NF-κB) activity by immunofluorescence test. Our results revealed a higher production of NO in active BD compared with the inactive stage and healthy controls. We observed that ATRA inhibits NO production in BD both in active and inactive stages and inhibits NF-κB translocation. In conclusion, we report a relationship between NO production and the disease activity. ATRA down-regulates NO production in BD patients. This immunomodulatory effect seems to be mediated through NF-κB pathway. All these findings suggest that ATRA could be considered as a promising therapy for BD.

Beneficial role of the probiotic mixture Ultrabiotique on maintaining the integrity of intestinal mucosal barrier in DSS-induced experimental colitis.

The etiology of inflammatory bowel diseases which include ulcerative colitis (UC) and Crohn disease has not yet been clarified. Several hypotheses suggest a change in composition of gut microflora along with an impaired mucosal barrier that lead to excessive mucosal immunologic responses. Increased production of nitric oxide (NO) contributes greatly to the tissue injury caused by chronic inflammation. Evidence indicates that the mucus layer covering the epithelium is altered during UC and experimental colitis. Our aim in this study was to investigate the potential therapeutic effect of probiotic during DSS-induced colitis by modulating the immune system and colonic mucus production. For that purpose, the probiotic formulation Ultrabiotique(®) (Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus plantarum and Bifidobacterium breve) was administered daily for 7 d to mice with colitis. Probiotic supplementation improved clinical symptoms and histological alterations observed during DSS induced colitis. Ultrabiotique(®) treatment down regulated the NO production by peritoneal macrophages of DSS-treated mice and enhanced mucus production in both DSS-treated and healthy mice. In conclusion, the modification of microflora by the Ultrabiotique(®) played a beneficial role in maintaining the integrity of the intestinal mucosal barrier and promoted tissue repair.