Protoscolicidal activity of Atriplex halimus leaves extract against Echinococcus granulosus protoscoleces.

Cystic echinococcosis, an endemic zoonosis in Algeria, is caused by the development of the helminth Echinococcus granulosus. Surgery remains the main treatment despite inducing relapse and several adverse reactions. In this context, natural scolicidal agents seem to be promising tools to overcome these reactions. In our study, we evaluated the phytochemical contents, antioxidant activity and scolicidal effect of Atriplex halimus. In this context, the aqueous extract from AH leaves (AHE) was subjected to preliminary phytochemical screening by HPLC. The in vitro antioxidant activity was determined by DPPH test. The cytotoxicity of AHE was evaluated in murine peritoneal macrophages and cell viability was examined by MTT assay. Moreover, different concentrations of AHE (20, 40, 50, 60 and 100 mg/ml) were tested on E. granulosus protoscoleces (PSC) cultures, during different times of incubation (15, 30, 60, 90, 120 and 180 min). The viability was evaluated by eosin exclusion test. The morphological and ultrastructural damages were evaluated by SEM. Our results indicate that total phenolic and flavonoids contents were 37.93 µg of Gallic acid equivalent per mg of extract (GAE/mg E) and 18.86 µg of Quercetin equivalent per mg (QE/mg E) respectively. Furthermore, AHE has an antioxidant activity with an IC50 of 0.95 mg/ml. Interestingly, the extracts did not exhibit any cytotoxic effect against murine peritoneal macrophages. Moreover, our study indicated a significant scolicidal activity time- and dose-dependent. At 60 and 100 mg/ml; and after 120 min of incubation; the mortality rate was 99.36 and 100%, respectively. The parasite's tegument is one of the plant's targets as demonstrated by SEM. Our findings show the benefits of Atriplex halimus extract as a new promising scolicidal tool in hydatid cyst treatment.

Vitamin D Levels Correlate with Metabolic Syndrome Criteria in Algerian Patients: The Ex-vivo Immunomodulatory Effect of α, 25 Dihydroxyvitamin D3.

BACKGROUND: Metabolic syndrome (MetS) is a combination of metabolic disorders with increased risks for several diseases, such as cardiovascular diseases and diabetes. It is associated with the presence of various inflammatory molecules. Vitamin D plays an important role in the regulation of metabolism homeostasis. OBJECTIVE: The main goal of this work is to investigate vitamin D levels among Algerian MetS patients and its possible outcomes on key molecules of the immune response, as well, the immunomodulatory effects of its active metabolite. METHODS: We evaluated vitamin D status by the electrochemiluminescence method, Nitric Oxide (NO) levels by the Griess method and Matrix Metalloproteinases (MMPs) activities such as MMP-2 and MMP-9 by zymography in plasma of patients and healthy controls (HC). The immunomodulatory effects of the active metabolite of vitamin D (α-25 (OH)2D3) on the production of NO, IL-6, IL-10, TGF- ß and s-CTLA-4 were assessed by Griess method and ELISA, in peripheral blood mononuclear cells (PBMCs) of Algerian MetS patients and HC. MMPs activities were also determined ex-vivo, while iNOS expression was assessed by immunofluorescence staining. RESULTS: Severe vitamin D deficiency was registered in Algerian MetS patients. The deficiency was found to be associated with an elevated in vivo NO production and high MMPs activity. Interestingly, α-25 (OH)2D3 declined the NO/iNOS system and IL-6 production, as well as MMPs activities. However, the ex-vivo production of IL-10, TGF-ß increased in response to the treatment. We observed in the same way, the implication of s-CTLA-4 in MetS, which was markedly up-regulated with α-25 (OH)2D3. CONCLUSION: Our report indicated the relationship between MetS factors and Vitamin D deficiency. The ex-vivo findings emphasize its impact on maintaining regulated immune balance.

Potential role of NF-κB pathway in the immuno-inflammatory responses during human cystic echinococcosis.

Cystic echinococcosis (CE) induces in the human host innate and adaptive immune response that plays an important role in controlling the immunopathogenesis. Due to the crucial role of nuclear factor kappa B (NF-κB) in regulating immuno-inflammatory processes, we investigated its potential contribution in systemic and local immuno-inflammatory responses in primary CE patients and relapsed patients. The expression of NF-κB and inducible nitric oxide synthase (iNOS) was analyzed in peripheral blood mononuclear cells (PBMC) as well as in pericystic layer of pulmonary hydatid cysts from Algerian primary CE patients and relapsed patients. Tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) production was evaluated in plasma samples. Our results showed high iNOS and NF-κB expression in both PBMCs and pericystic histiocytes from primary CE patients. In addition, substantial amounts of systemic NO and TNF-α were detected in the same patients. Remarkably, relapsed patients exhibited a low NF-κB and iNOS expression associated with low amounts of plasmatic TNF-α and NO. Collectively, NF-κB/iNOS pathway is involved in the host defense mechanisms at the systemic and local level during primary CE. Our results indicate that the inhibition of this pathway in relapsed patients will attenuate protective immunity and promote parasite escape. This study allowed to identify a novel predictive biomarkers of hydatidosis.

Antihydatic and immunomodulatory effects of Punica granatum peel aqueous extract in a murine model of echinococcosis.

OBJECTIVE: To investigate the effect of pomegranate peel aqueous extract (PGE) on the development of secondary experimental echinococcosis and on the viability of Echinococcus granulosus protoscoleces, and the immunomodulatory properties of PGE. METHODS: Swiss mice were inoculated intraperitoneally with viable protoscoleces. Then, PGE was orally administered daily during cystic echinococcosis development. Cyst development and hepatic damage were macroscopically and histologically analyzed. The production of nitric oxide and TNF-α was assessed in plasma and the hepatic expression of iNOS, TNF-α, NF-κB and CD68 was examined. Moreover, protoscoleces were cultured and treated with different concentrations of PGE. RESULTS: It was observed that in vitro treatment of protoscoleces caused a significant decrease in viability in a PGE-dose-dependent manner. In vivo, after treatment of cystic echinococcosis infected mice with PGE, a significant decrease in nitric oxide levels (P < 0.0001) and TNF-α levels (P < 0.001) was observed. This decline was strongly related to the inhibition of cyst development (rate of hydatid cyst growth inhibition = 63.08%) and a decrease in CD68 expression in both the pericystic layer of hepatic hydatid cysts and liver tissue (P < 0.0001). A significant diminution of iNOS, TNF-α and NF-κB expression was also observed in liver tissue of treated mice (P < 0.0001). CONCLUSIONS: Our results indicate an antihydatic scolicidal effect and immunomodulatory properties of PGE, suggesting its potential therapeutic role against Echinococcus granulosus infection.

Comparative study of nitric oxide (NO) production during human hydatidosis: relationship with cystic fluid fertility.

Human hydatidosis is characterized by a prolonged coexistence of Echinococcus granulosus and its host without effective rejection of the parasite. This parasitic infection constitutes a major health problem in Algeria. In this study, we investigated in vivo production of nitrite (NO(2)(-) + NO(3)(-)) in sera of Algerian patients carrying different cyst locations. Nitrite (NO(2)(-) + NO(3)(-)) levels were evaluated by the Griess method. Our results indicated that the levels of nitrite were significantly higher in the sera of hydatic patients than those of healthy controls supporting the involvement of nitric oxide (NO) in antihydatic action. The levels of nitrite in sera of the patients with hepatic hydatidosis were significantly higher than those with pulmonary infection. The lower serum (NO(2)(-) + NO(3)(-)) levels were observed in the relapsing cases. In addition, (NO(2)(-) + NO(3)(-)) levels of fertile hydatic fluids were significantly higher compared to infertile fluids. Our results suggest that the presence of NO products in hydatic fluids seems to be related to the location and the fertility of hydatic cysts. The assessment of protein concentration in hydatic fluids showed that the concentration of proteins was not exclusively dependent on the fertility but on the cyst locations. The assessment of (NO(2)(-) + NO(3)(-)) production in hydatic patients may be a useful tool to evaluate effector mechanisms of NO and clinical manifestations.

Interleukin-17A correlates with interleukin-6 production in human cystic echinococcosis: a possible involvement of IL-17A in immunoprotection against Echinococcus granulosus infection.

Hydatidosis is a parasitic disease caused by the development, in humans and other mammals, of the larval form of Taenia, Echinococcus granulosus. It is one of the world's major zoonotic infections. This study aimed to examine interleukin-6 (IL-6), interferon-γ (IFN-γ) and interleukin-17A (IL-17A) production in patients with cystic echinococcosis (CE), and the role of IL-17A in the modulation of the immune response against the extracellular parasite, E. granulosus. A relationship between IL-6, IL-17A production and C reactive Protein (CRP) levels was also assessed. IL-6, IFN-γ, IL-17A and CRP production were determined in serum from Algerian hydatid patients. Cytokine production was also measured in supernatants from cultures of peripheral blood mononuclear cells (PBMCs) from hydatid patients stimulated by a major parasitic antigen (antigen-5). The increased activity of IL-6, IFN-γ and IL-17A were observed in most serum samples from patients. In contrast, healthy controls showed only minor levels. Similarly, high levels of CRP were detected. Our in vitro results indicate a positive correlation between IL-6, IFN-γ and IL-17A production in PBMC culture supernatants. However, IL-6, IFN-γ and IL-17A activity was low in serum and supernatants of PBMC cultures from relapsing patients, and there was no evidence of an immune response against parasitic antigen. Collectively, our results show that IL-17A was produced during human cystic echinococcosis, and was involved in the host defense mechanisms against the extracellular parasite E. granulosus. Our data suggest that IL-17A plays an immunoprotective role in this parasitic, helminth infection.

Involvement of IL-10 and IL-4 in evasion strategies of Echinococcus granulosus to host immune response.

Human echinococcosis is one of the world's major zoonotic infections. In this study, our aim is to clarify one of the strategies used by the parasite for evasion and prolonged infestation in the host. We wished to provide further immunological evidence for the involvement of IL-10/IL-4 in these mechanisms. In this regard, we investigated the effects of IL-4 and IL-10 on protoscoleces (PSC: the larval form of the parasite), co-cultured with patient PBMC. Furthermore, we used IL-4 and IL-10 antibodies to confirm this effect. Our results showed that IL-4 and IL-10 reduced PSC killing. This reduction correlates with an decrease in NO production by PBMC. In conclusion, the results reported here suggest that IL-4/IL-10 impairs the Th1 protective response and allows the parasite to survive in hydatid patients.

In Vitro Study of Nitric Oxide Metabolites Effects on Human Hydatid of Echinococcus granulosus.

Hydatidosis is characterized by the long-term coexistence of larva Echinococcus granulosus and its host without effective rejection. Previous studies demonstrated nitric oxide (NO) production (in vivo and in vitro) during hydatidosis. In this study, we investigated the direct in vitro effects of NO species: nitrite (NO(2) (-)), nitrate (NO(3) (-)) and peroxynitrite (ONOO(-)) on protoscolices (PSCs) viability and hydatid cyst layers integrity for 24 hours and 48 hours. Our results showed protoscolicidal activity of NO(2) (-) and ONOO(-) 24 hours and 3 hours after treatment with 320 muM and 80 muM respectively. Degenerative effects were observed on germinal and laminated layers. The comparison of the in vitro effects of NO species on the PSCs viability indicated that ONOO(-) is more cytotoxic than NO(2) (-). In contrast, NO(3) (-) has no effect. These results suggest possible involvement of NO(2) (-) and ONOO(-) in antihydatic action and point the efficacy of these metabolites as scolicidal agents.

In vivo IL-12 and IL-8 production in hydatic patients and their possible diffusion in hydatid cysts.

Cystic echinococcosis (CE) is caused by infection with the larval stage of the cestode Echinococcus granulosus. It is one of the world's major zoonotic infections. Variability and severity of clinical expression of this parasitosis are associated with duration and intensity of infection. They are also related to the variety of human immunological responses to the hydatic antigens. The aim of this work is to study the inflammatory response associated with human hydatidosis by evaluating the possible roles of the proinflammatory cytokines in hydatic patients. We investigated the patterns of IL-12 and IL-8 in serum from Algerian hydatic patients. Serum IL-12 and IL-8 levels are significantly higher in patients with hydatidosis than in control subjects. Furthermore, cytokines secretion correlates with disease statues (cystic localizations and clinical stage). These data indicate that infection with E. granulosus is associated with high levels of circulating IL-12 and IL-8. Moreover, our data, to our knowledge, constitute the first report of IL-12 and IL-8 diffusion into the hydatid cyst. Our results underline the permeability of the cyst wall to the soluble immune system of the host. The relationship between cyst fertility and cytokine infiltration indicates a strong host-parasite interaction. All these findings have important implications for the diagnosis of hydatidosis in humans.

In vitro antihydatic action of IFN-gamma is dependent on the nitric oxide pathway.

Hydatidosis is a widely endemic helminthic disease vectored in human by the larval stage of the metacestode Echinococcus granulosus. It is characterized by the long-term coexistence of chronic infection with detectable humoral and cellular responses against the macroparasite. Previous studies demonstrated interferon-gamma (IFN-gamma) and nitric oxide (NO) production (in vivo and in vitro) during hydatidosis. In this study, we tested the hypothesis that NO production after IFN-gamma induction may constitute a host defense against E. granulosus. We also investigated the IFN-gamma effect on protoscolices (larval form of the parasite) viability in coculture with hydatid patients' peripheral blood mononuclear cells (PBMC). PBMCs from hydatic patients incubated with IFN-gamma (100 U/mL) alone are effective in the killing of protoscolices. This scolicidal activity is concomitant with elevation of nitrite levels. NO release and cytotoxic activity are inhibited by N-monomethyl-L-arginine (L-NMMA), a specific inhibitor of the NO pathway and increased by L-arginine, an NO precursor, and tetrahydrobiopterin (BH4), a nitric oxide synthase (NOS) cofactor. Our results indicate that IFN-gamma mediated iNOS induction as one of host defense mechanism against human E. granulosus infection.