Endogenous and Uric Acid-Induced Activation of NLRP3 Inflammasome in Pregnant Women with Preeclampsia.

Preeclampsia (PE) is a specific syndrome of pregnancy, characterized by hypertension and proteinuria. This pathology is associated with hyperuricemia and elevated serum levels of inflammatory cytokines. Uric acid crystals may activate an intracellular complex called inflammasome, which is important for processing and release of inflammatory cytokines. This study investigated the state of monocyte activation, both endogenous and stimulated with monosodium urate (MSU), by gene expression of NLRP1 and NLRP3 receptors as well as their association with inflammatory cytokines expression. Monocytes were obtained from peripheral blood of 23 preeclamptic pregnant women, 23 normotensive pregnant women (NT) and 23 healthy non-pregnant women (NP). Inflammasome activation was evaluated by the gene expression of NLRP1, NLRP3, caspase-1, IL-1ß, IL-18 and TNF-α by RT-qPCR in unstimulated monocytes (endogenous expression), or after cell stimulation with MSU (stimulated expression). The concentration of cytokines was assessed by ELISA. In preeclamptic pregnant women, gene expression of NLRP1, NLRP3, caspase-1, IL-1ß and TNF-α by monocytes stimulated or not with MSU was significantly higher than in NT and NP groups. Stimulation of monocytes from preeclamptic and non-pregnant women with MSU induced increased gene expression of NLRP3, caspase-1 and TNF-α in relation to the endogenous expression in these groups, while this was not observed in the NT group. The cytokine determination showed that monocytes from women with PE produced higher endogenous levels of IL-1ß, IL-18 and TNF-α compared to the other groups, while the stimulus with MSU led to higher production of these cytokines in preeclamptic group than in the NT group. In conclusion, the results showed increased basal gene expression of NLRP1 and NLRP3 receptors in monocytes from PE group. These cells stimulation with MSU demonstrates that uric acid plays a role in NLRP3 inflammasome activation, suggesting the participation of this inflammatory complex in the pathogenesis of preeclampsia.

Elevated hyaluronan and extracellular matrix metalloproteinase inducer levels in women with preeclampsia.

PURPOSE: Preeclampsia (PE) is a specific syndrome of pregnancy clinically identified by hypertension and proteinuria from the 20th week of gestation associated with a systemic inflammatory response and oxidative stress. While pro-inflammatory cytokines have been extensively studied in PE, other factors in the circulation that also influence the magnitude of inflammation have received much less attention. The present study compared serum concentrations of five immune-regulatory compounds in normotensive pregnant women and in women with gestational hypertension (GH) or PE. METHODS: Sixty women with PE, 53 with GH and 40 normotensive women paired by gestational age were evaluated. Sera were evaluated for concentrations of extracellular matrix metalloproteinase inducer (EMMPRIN), hyaluronan, gelsolin, visfatin and histone 2B by ELISA. Differences between groups were analyzed by nonparametric tests, with a significance level of 5%. RESULTS: Increased levels of EMMPRIN and hyaluronan were present in preeclamptic women as compared to the GH and normotensive groups. There was no difference between groups in gelsolin, visfatin or histone 2B. CONCLUSION: Increased release of EMMPRIN and hyaluronan may contribute to an elevated pro-inflammatory response and tissue damage in women with PE.

Hepatoprotective and anti-inflammatory effects of silibinin on experimental preeclampsia induced by L-NAME in rats.

AIMS: Inhibition of nitric oxide synthase with N-omega-nitro-l-arginine methyl ester (l-NAME) has been employed as an experimental model of human preeclampsia. This study determined the protective effect of silibinin, a flavonoid with anti-inflammatory and hepatoprotective properties on the deleterious effects observed in experimentally induced preeclampsia in rats. MAIN METHODS: Pregnant Wistar rats were treated during gestation (days 10-20) with l-NAME (70-80mg/kg/day) in drinking water or with l-NAME plus silibinin (100mg/kg/day, orally) starting at day 0, day 7 or day 14 of pregnancy. Systolic blood pressure was recorded from gestation days 0 to 21. A control group of pregnant non-treated rats was analyzed similarly. On day 21 the rats were euthanized and the following parameters were evaluated: proteinuria, platelet count, liver histopathology and reproductive outcome. Tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1ß), IL-6, IL-10 and interferon-gamma (IFN-γ) were determined in liver homogenate by enzyme immunoassay. KEY FINDINGS: In comparison with the l-NAME group the silibinin treatment reduced the values of systolic blood pressure, proteinuria, TNF-α, IL-1ß and IFN-γ in liver, normalized the platelet count and improved fetal outcomes. Histopathological lesions in liver of the l-NAME group showed intense mononuclear inflammatory infiltrate and thickening of muscle tunica of arterial vessel, mainly in the periportal area. Silibinin treatment induced attenuation of periportal inflammatory infiltrate, showing an association between inflammatory infiltrate and TNF-α, IL-1ß and IFN-γ levels in liver homogenate. SIGNIFICANCE: Silibinin administration to l-NAME-treated rats displays anti-inflammatory and immunomodulatory actions that may contribute to its hepatoprotective effects and improve reproductive outcomes in experimental preeclampsia.

Downregulation of nuclear factor-kappa B (NF-kappaB) pathway by silibinin in human monocytes challenged with Paracoccidioides brasiliensis.

AIMS: Silibinin is the major active component of silymarin, a polyphenolic plant flavonoid that has anti-inflammatory effects. The modulatory effect of silibinin on monocyte function against Paracoccidioides brasiliensis (Pb18) has not yet been demonstrated. The present study investigated whether the effect of silibinin on nuclear factor-kappa B (NF-kappaB) pathways may affect the production of tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10), transforming growth factor beta (TGF-beta1), prostaglandin E(2) (PGE(2)), nitric oxide (NO) and fungicidal activity of human monocytes challenged in vitro with Pb18. MAIN METHODS: Peripheral blood monocytes from healthy individuals were treated with silibinin and challenged with Pb18 for 18h. TNF-alpha, IL-10, TGF-beta1 and PGE(2) expression were determined by immunoenzymatic assay (ELISA) and NO release was determined by the accumulation of nitrite in culture supernatants. Fungicidal activity of monocytes was analyzed after treatment with interferon-gamma plus silibinin and challenge with Pb18. NF-kappaB activation in cultured monocytes was evaluated by flow cytometry and ELISA. KEY FINDINGS: Silibinin partially inhibited p65NF-kappaB activation as the number of cells expressing this factor was reduced and the concentration of nuclear p65NF-kappaB was low, compared to untreated controls. The addition of silibinin also resulted in suppression of TNF-alpha, IL-10, TGF-beta1, PGE(2) and NO production but did not affect the fungicidal activity of monocytes against Pb18. SIGNIFICANCE: Silibinin exerts anti-inflammatory and anti-fibrotic effects on CD14+/- human monocytes challenged by Pb18 by partial inhibition of p65NF-kappaB activation.