Increased reactive oxygen species and tumor necrosis factor-alpha production by monocytes are associated with elevated levels of uric acid in pre-eclamptic women.

PROBLEM: To evaluate associations between hyperuricemia and increases in production of reactive oxygen species (ROS) and tumor necrosis factor alpha (TNF-α) in pre-eclamptic pregnancies. METHOD OF STUDY: This study investigated serum uric acid levels, monocyte production of TNF-α, superoxide anion (O(2)(-)) and hydrogen peroxide (H(2)O(2)), as well as superoxide dismutase (SOD) and catalase (CAT) activities in erythrocytes from 30 women with pre-eclampsia (PE) compared with 30 normotensive (NT) pregnant women in the last trimester of pregnancy. RESULTS: Serum uric acid levels (6.1 versus 2.8 mg/dL) as well as endogenous O(2)(-) (2.2 versus 1.6 nm), H(2)O(2) (1.8 versus 1.4 nm) and TNF-α (91.6 versus 40.4 pg/mL) released from monocytes were significantly higher in the pre-eclamptic group than in the NT group (P < 0.05). SOD activity in erythrocytes was also significantly elevated in the PE group (5969.2 versus 4834.7 U/g Hb). No significant difference between groups was observed in relation to CAT activity. CONCLUSIONS: Elevated serum uric acid levels are correlated with higher O(2)(-) and TNF-α production by monocytes in women with PE. This may contribute to the enhanced oxidative and inflammatory state characteristic of this disorder.

Interactions between TLR2, TLR4, and mannose receptors with gp43 from Paracoccidioides brasiliensis induce cytokine production by human monocytes.

The glycoprotein gp43 is an immunodominant antigen secreted by Paracoccidioides brasiliensis, the agent of paracoccidioidomycosis. The present study evaluated whether gp43 can interact with toll-like (TLR2, TLR4) and mannose (MR) receptors on the surface of human monocytes, and how that affects their expression and cytokine production. Monocytes were incubated with or without monoclonal antibodies anti-TLR2, anti-TLR4, or anti-MR, individually or in combination, prior to the addition of gp43. The gp43 binding to monocyte surface, as well as expression of TLR2, TLR4, and MRs were analyzed by flow cytometry, while production of TNF-α and IL-10 was monitored by ELISA. The results suggested that gp43 binds to TLR2, TLR4, and MR receptors, with TLR2 and MR having the strongest effect. All three receptors influenced the production of IL-10, while TNF-α production was associated with expression of TLR4 and MR. The modulatory effect of gp43 was demonstrated by high levels of TLR4 expression associated with increased production of TNF-α after 4 h of culture. Alternatively, high levels of TLR2 expression, and elevated production of IL-10, were detected after 18 h. We showed that interaction between gp43 and monocytes may affect the innate immune response by modulating the expression of the pattern recognition receptors TLR2, TLR4 and MR, as well as production of pro- and anti-inflammatory cytokines.