Vascular contraction of umbilical arteries of pregnant women with preeclampsia.

Objective: Potassium channels have an important role in the vascular adaptation during pregnancy and a reduction in the expression of adenosine triphosphate-sensitive potassium channels (Katp) has been linked to preeclampsia. Activation of Katp induces vasodilation; however, no previous study has been conducted to evaluate the effects of the inhibition of these channels in the contractility of preeclamptic arteries. Glibenclamide is an oral antihyperglycemic agent that inhibits Katp and has been widely used in vascular studies. Methods: To investigate the effects of the inhibition of Katp, umbilical arteries of preeclamptic women and women with healthy pregnancies were assessed by vascular contractility experiments, in the presence or absence of glibenclamide. The umbilical arteries were challenged with cumulative concentrations of potassium chloride (KCl) and serotonin. Results: There were no differences between the groups concerning the maternal age and gestational age of the patients. The percentage of smokers, caucasians and primiparae per group was also similar. On the other hand, blood pressure parameters were elevated in the preeclamptic group. In addition, the preeclamptic group presented a significantly higher body mass index. The newborns of both groups presented similar APGAR scores and weights. Conclusion: In the presence of glibenclamide, there was an increase in the KCl-induced contractions only in vessels from the PE group, showing a possible involvement of these channels in the disorder.

EGCG, a Green Tea Compound, Increases NO Production and Has Antioxidant Action in a Static and Shear Stress In Vitro Model of Preeclampsia.

Preeclampsia (PE) is a gestational hypertensive disease characterized by endothelial dysfunction. Epigallocatechin-3-gallate (EGCG), the main compound in green tea, is a promising therapeutic target for the disease. By activating eNOS, EGCG increased NO production and exerted an important antioxidant action, but its specific impact in the context of PE remains understudied. The aim of this study is to evaluate the effects of EGCG on endothelial function in static and shear stress in in vitro models of PE. Endothelial cells were incubated with healthy (HP) and preeclamptic (PE) pregnant women's plasma, and the latter group was treated with EGCG. Additionally, NOS (L-NAME) and PI3K protein (LY249002) inhibitors were also used. The levels of NO, ROS, and O2•- were evaluated, as well as the antioxidant potential. These investigations were also carried out in a shear stress model. We found that EGCG increases the NO levels, which were reduced in the PE group. This effect was attenuated with the use of L-NAME and LY249002. Furthermore, EGCG increased the antioxidant capacity of PE, but its action decreased with LY294002. In cells subjected to shear stress, EGCG increased nitrite levels in the PE group and maintained its action on the antioxidant capacity. This is the first study of the effects of EGCG in this experimental model, as well as the investigation of its effects along with shear stress. Our findings suggest that EGCG improves parameters of endothelial dysfunction in vitro, making it a promising target in the search for treatments for the disease.

Vascular contraction of umbilical arteries of pregnant women with preeclampsia

Abstract Objective: Potassium channels have an important role in the vascular adaptation during pregnancy and a reduction in the expression of adenosine triphosphate-sensitive potassium channels (Katp) has been linked to preeclampsia. Activation of Katp induces vasodilation; however, no previous study has been conducted to evaluate the effects of the inhibition of these channels in the contractility of preeclamptic arteries. Glibenclamide is an oral antihyperglycemic agent that inhibits Katp and has been widely used in vascular studies. Methods: To investigate the effects of the inhibition of Katp, umbilical arteries of preeclamptic women and women with healthy pregnancies were assessed by vascular contractility experiments, in the presence or absence of glibenclamide. The umbilical arteries were challenged with cumulative concentrations of potassium chloride (KCl) and serotonin. Results: There were no differences between the groups concerning the maternal age and gestational age of the patients. The percentage of smokers, caucasians and primiparae per group was also similar. On the other hand, blood pressure parameters were elevated in the preeclamptic group. In addition, the preeclamptic group presented a significantly higher body mass index. The newborns of both groups presented similar APGAR scores and weights. Conclusion: In the presence of glibenclamide, there was an increase in the KCl-induced contractions only in vessels from the PE group, showing a possible involvement of these channels in the disorder.

Sildenafil attenuates oxidative stress and endothelial dysfunction in lead-induced hypertension.

Lead (Pb) reduces NO bioavailability, impairs the antioxidant system, and increases the generation of reactive oxygen species (ROS). Pb-induced oxidative stress may be responsible for the associated endothelial dysfunction. Sildenafil has shown nitric oxide (NO)-independent action, including antioxidant effects. Therefore, we examined the effects of sildenafil on oxidative stress, reductions of NO and endothelial dysfunction in Pb-induced hypertension. Wistar rats were distributed into three groups: Pb, Pb + sildenafil and Sham. Blood pressure and endothelium-dependent vascular function were recorded. We also examined biochemical determinants of lipid peroxidation and antioxidant function. ROS levels, NO metabolites and NO levels in human umbilical vein endothelial cells (HUVECs) were also evaluated. Sildenafil prevents impairment of endothelium-dependent NO-mediated vasodilation and attenuates Pb-induced hypertension, reduces ROS formation, enhances superoxide dismutase (SOD) activity and antioxidant capacity in plasma and increases NO metabolites in plasma and HUVECs culture supernatants, while no changes were found on measurement of NO released from HUVECs incubated with plasma of the Pb and Pb + sildenafil groups compared with the sham group. In conclusion, sildenafil protects against ROS-mediated inactivation of NO, thus preventing endothelial dysfunction and attenuating Pb-induced hypertension, possibly through antioxidant effects.

Markers of Endothelial Dysfunction Are Attenuated by Resveratrol in Preeclampsia.

Preeclampsia (PE) is characterized by great endothelial dysfunction, decreased nitric oxide (NO) bioavailability, and higher levels of arginase activity. In the present study, we investigated the potential modulatory effects of trans-resveratrol (RSV) on arginase and endothelial dysfunction biomarkers in endothelial cells exposed to plasma from patients with PE and healthy pregnant (HP) women, and umbilical arteries from patients with PE. Human umbilical vein endothelial cells (HUVECs) were incubated with pooled plasma from 10 HP or 10 PE pregnant women and RSV; umbilical arteries from patients with PE were incubated with RSV; intracellular NO and total reactive oxygen species (ROS) levels were assessed using a probe that interacted with these radicals; total arginase activity was evaluated measuring the urea produced; total antioxidant capacity was measured using the ferric reduction ability power (FRAP) assay; and endothelial dysfunction biomarkers were assessed using qPCR in endothelial cells and umbilical arteries. RSV increased NO levels and decreased total arginase activity in endothelial cells incubated with plasma from patients with PE. In addition, RSV increased total antioxidant capacity and downregulated endothelial dysfunction biomarkers, such as intercellular adhesion molecule-1 (ICAM-1), von Willebrand factor (vWF), and Caspase-3, (CASP-3), in endothelial cells and umbilical arteries from PE patients. RSV treatment positively modulated the L-arginine-NO pathway, decreased arginase activity, and increased antioxidant capacity, in addition to downregulating endothelial dysfunction biomarkers.

Glibenclamide Increases Nitric Oxide Levels and Decreases Oxidative Stress in an In Vitro Model of Preeclampsia.

(1) Background: The bioavailability of nitric oxide (NO) and oxidative stress are important events related to the pathophysiology of preeclampsia (PE). In this present study, we aimed to evaluate the antioxidant effect of glibenclamide (GB) on the NO synthesis, oxidative stress, and antioxidant capacity in endothelial cells incubated with plasma from preeclamptic (PE) and normotensive pregnant women (NT). (2) Methods: Human umbilical vein endothelial cells (HUVECs) were incubated with a plasma pool from 10 NT and 10 PE pregnant women; NO/NOx quantification and ROS levels were assessed by a fluorescence compound; lipid peroxidation was evaluated employing thiobarbituric acid (TBA); and total antioxidant capacity was measured by ferric reduction ability power (FRAP) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). (3) Results: We found that endothelial cells incubated with plasma from PE showed lower NO and NOx levels compared with the NT group. However, GB treatment increased these levels, as well as the antioxidant capacity. Furthermore, a decrease was observed in ROS generation and lipid peroxidation (4) Conclusions: The GB treatment exerted a positive effect on the NO/NOx production by HUVEC incubated with plasma from NT and PE pregnant women, as well as in the reduction in oxidative stress and increase in the antioxidant capacity.

Inflammasomes in placental explants of women with preeclampsia cultured with monosodium urate may be modulated by vitamin D.

OBJECTIVES: Preeclampsia (PE) is an important syndrome of gestation characterized by placental and systemic inflammation. High plasma concentration of uric acid are frequently associated with inflammation and endothelial dysfunction and may contribute to PE pathogenesis. This study aimed to evaluate the vitamin D (VD) immunomodulatory effect on the NLRP1/NLRP3 inflammasomes in placental explants from preeclamptic (PE) and normotensive (NT) pregnant women. STUDY DESIGN: Placental explants from 10 late-onset PE (LOPE), 10 early-onset PE (EOPE), and 10 NT pregnant women were cultured with or without monosodium urate (MSU) and VD. MAIN OUTCOME MEASURES: Gene and protein expression of NLRP1, NLRP3, HMGB1, caspase-1, interleukin-1 beta (IL-1ß), and IL-18 were determined by quantitative PCR and Western blotting/ELISA. Statistical significance was accepted at p < 0.05. RESULTS: Basal gene and protein expression of NLRP1/NLRP3 and IL-1ß, IL-18 and HMGB1 were significantly higher in explants from EOPE compared to LOPE and NT pregnant women. In addition, culture with MSU increased these inflammatory markers, and concomitant treatment with MSU+VD decreased this effect. CONCLUSIONS: The results demonstrated that NLRP1 and NLRP3 inflammasomes are upregulated in the placental tissue of EOPE women, associated with high production of inflammatory cytokines. The in vitro treatment with VD downregulated placental inflammasomes induced by MSU, suggesting its immunomodulatory role in the systemic inflammation of PE.

Nebivolol Increases Nitric Oxide Synthase via ß3 Adrenergic Receptor in Endothelial Cells Following Exposure to Plasma from Preeclamptic Patients.

Background: Low bioavailability of nitric oxide (NO) is related to the pathophysiology of preeclampsia (PE). In the present study, we investigated the effect of nebivolol (NEB), a ß3-receptor agonist with vasodilator properties, on the NO synthesis in endothelial cells incubated with plasma from preeclamptic patients. Methods and results: Human umbilical vein endothelial cells (HUVECs) were incubated with plasma from healthy pregnant (HP) and PE women; NO quantification was assessed by a fluorescence compound. We found that endothelial cells incubated with plasma from women with PE show lower NO levels compared with the HP group (p < 0.0001). However, NEB treatment increases NO levels, partially, mediated by ß3 adrenergic receptors (p < 0.0001) and through eNOS activation (p < 0.0001). Conclusions: Our results suggest that NEB acts in NO synthesis through eNOS activation and ß3 adrenergic receptors in the endothelium. However, further studies will be needed to understand this molecule.

Vitamin D decreases cell death and inflammation in human umbilical vein endothelial cells and placental explants from pregnant women with preeclampsia cultured with TNF-α.

This study evaluated the impact of vitamin D on Human Umbilical Vein Endothelial Cells (HUVEC) and inflammation in placental explants from women with preeclampsia (PE). HUVEC and explants from 10 late-onset PE (LOPE), 10 early-onset (EOPE), and 10 normotensive (NT) pregnant women were cultured with/without tumor necrosis factor (TNF-α) and VD. Interleukin-1ß (IL-1ß), 18 (IL-18), TNF-α, and TNF-related apoptosis-inducing ligand (TRAIL) were detected by ELISA. High mobility group box 1 (HMGB1) was determined by qPCR/Western blotting, and cell death by flow cytometry. Statistical significance was accepted at p < .05. Compared to the NT group, the endogenous levels of IL-1ß, TNF-α, and IL-18 were higher in the PE group. The stimulus with TNF-α increased cytokines in NT, TNF-α in EOPE/LOPE, IL-18 in LOPE, and all cytokines in HUVEC. TNF-α+VD treatment decreased cytokines in explant and HUVEC supernatants. TRAIL was higher in EOPE versus NT, while TNF-α increased this receptor in NT versus control. In HUVEC, TNF-α increased TRAIL versus control, and TNF-α+VD decreased levels compared to only TNF-α stimulus. Protein expression of HMGB1 was higher in explant cultures treated with TNF-α and decreased after TNF-α+VD treatment in all groups, and gene/protein expression in HUVEC. Gene expression was elevated in EOPE versus NT and LOPE, and TNF-α increased HMGB1 in NT versus control, while TNF-α+VD decreased mRNA levels in EOPE. TNF-α stimulus increased late apoptosis in HUVEC, while VD increased viability. These in vitro observations suggest that VD administration to women with preeclampsia may be beneficial in reducing placental inflammation and cell death.

NLRP3 Activation and Its Relationship to Endothelial Dysfunction and Oxidative Stress: Implications for Preeclampsia and Pharmacological Interventions.

Preeclampsia (PE) is a specific syndrome of human pregnancy, being one of the main causes of maternal death. Persistent inflammation in the endothelium stimulates the secretion of several inflammatory mediators, activating different signaling patterns. One of these mechanisms is related to NLRP3 activation, initiated by high levels of danger signals such as cholesterol, urate, and glucose, producing IL-1, IL-18, and cell death by pyroptosis. Furthermore, reactive oxygen species (ROS), act as an intermediate to activate NLRP3, contributing to subsequent inflammatory cascades and cell damage. Moreover, increased production of ROS may elevate nitric oxide (NO) catabolism and consequently decrease NO bioavailability. NO has many roles in immune responses, including the regulation of signaling cascades. At the site of inflammation, vascular endothelium is crucial in the regulation of systemic inflammation with important implications for homeostasis. In this review, we present the important role of NLRP3 activation in exacerbating oxidative stress and endothelial dysfunction. Considering that the causes related to these processes and inflammation in PE remain a challenge for clinical practice, the use of drugs related to inhibition of the NLRP3 may be a good option for future solutions for this disease.

Association between Adverse Maternal Clinical Outcomes and Imbalance of Cytokines and Angiogenic Factors in Preterm Preeclampsia.

OBJECTIVE: Preeclampsia (PE) is a pregnancy-specific syndrome characterized by abnormal levels of cytokines and angiogenic factors, playing a role in the disease development. The present study evaluated whether immunological markers are associated with the gestational age and with the disease severity in preeclamptic women. METHODS: Ninety-five women who developed PE were stratified for gestational age as preterm PE (< 37 weeks) and term PE (≥ 37 weeks of gestation) and compared for disease severity as well as plasma concentration of angiogenic factors and cytokines. The concentrations of placental growth factor (PlGF), vascular endothelial growth factor (VEGF), Fms-like soluble tyrosine kinase (sFlt-1) and soluble endoglin (sEng), as well as the cytokines, tumor necrosis factor-α (TNF-α) and interleukin 10 (IL-10), were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: The comparison between preeclamptic groups showed a higher percentage of severe cases in preterm PE (82.1%) than in term PE (35.9%). Similarly, the concentrations of TNF-α, sFlt-1, and sEng, as well as TNF-α/IL-10 and sFlt-1/PlGF ratios were significantly higher in the preterm PE group. In contrast, concentrations of PlGF, VEGF, and IL-10 were significantly lower in women with preterm PE. Negative correlations between TNF-α and IL-10 (r = 0.5232) and between PlGF and sFlt1 (r = -0.4158) were detected in the preterm PE. CONCLUSION: In pregnant women with preterm PE, there is an imbalance between immunological markers, with the predominance of anti-angiogenic factors and TNF-α, associated with adverse maternal clinical outcomes.

OBJETIVO: A pré-eclâmpsia (PE) é uma síndrome específica da gravidez caracterizada por níveis anormais de citocinas e fatores angiogênicos, que desempenham um papel no desenvolvimento da doença. Este estudo avaliou se os marcadores imunológicos estão associados à idade gestacional e à gravidade da doença em mulheres com pré-eclâmpsia. MéTODOS: Noventa e cinco mulheres que desenvolveram PE foram estratificadas pela idade gestacional em PE pré-termo (< 37 semanas) e PE a termo (≥ 37 semanas de gestação) e comparadas quanto à gravidade da doença, bem como à concentração plasmática de fatores angiogênicos e citocinas. As concentrações de fator de crescimento placentário (PlGF), fator de crescimento endotelial vascular (VEGF), tirosina quinase solúvel semelhante a Fms (sFlt-1) e endoglina solúvel (sEng), bem como as citocinas, fator de necrose tumoral alfa (TNF- α) e interleucina 10 (IL-10), foram determinados porensaio de imunoabsorção enzimática (ELISA, na sigla em inglês). RESULTADOS: A comparação entre os grupos com pré-eclâmpsia mostrou maior porcentagem de casos graves em PE pré-termo (82,1%) do que em PE a termo (35,9%). Da mesma forma, as concentrações de TNF-α, sFlt-1 e sEng, bem como as razões TNF-α/IL-10 e sFlt-1/PlGF foram significativamente maiores no grupo de PE pré-termo. Em contraste, as concentrações de PlGF, VEGF e IL-10 foram significativamente menores em mulheres com PE pré-termo. Correlações negativas entre TNF-α e IL-10 (r = 0.5232) e entre PlGF e sFlt1 (r = −0.4158) foram detectadas no grupo de PE pré-termo. CONCLUSãO: Em gestantes com PE pré-termo, ocorre um desequilíbrio entre os marcadores imunológicos, com predomínio de fatores antiangiogênicos e TNF-α, associados a desfechos clínicos maternos adversos.

Association between Adverse Maternal Clinical Outcomes and Imbalance of Cytokines and Angiogenic Factors in Preterm Preeclampsia / Associação entre desfechos maternos adversos e desbalanço de citocinas e fatores angiogênicos em pré-eclâmpsia pré-termo

Abstract Objective Preeclampsia (PE) is a pregnancy-specific syndrome characterized by abnormal levels of cytokines and angiogenic factors, playing a role in the disease development. The present study evaluated whether immunological markers are associated with the gestational age and with the disease severity in preeclamptic women. Methods Ninety-five women who developed PE were stratified for gestational age as preterm PE (< 37 weeks) and term PE (≥ 37 weeks of gestation) and compared for disease severity as well as plasma concentration of angiogenic factors and cytokines. The concentrations of placental growth factor (PlGF), vascular endothelial growth factor (VEGF), Fms-like soluble tyrosine kinase (sFlt-1) and soluble endoglin (sEng), as well as the cytokines, tumor necrosis factor-α (TNF-α) and interleukin 10 (IL-10), were determined by enzyme-linked immunosorbent assay (ELISA). Results The comparison between preeclamptic groups showed a higher percentage of severe cases in preterm PE (82.1%) than in term PE (35.9%). Similarly, the concentrations of TNF-α, sFlt-1, and sEng, as well as TNF-α/IL-10 and sFlt-1/PlGF ratios were significantly higher in the preterm PE group. In contrast, concentrations of PlGF, VEGF, and IL-10 were significantly lower in women with preterm PE. Negative correlations between TNF-α and IL-10 (r = 0.5232) and between PlGF and sFlt1 (r = 0.4158) were detected in the preterm PE. Conclusion In pregnant women with preterm PE, there is an imbalance between immunological markers, with the predominance of anti-angiogenic factors and TNF-α, associated with adverse maternal clinical outcomes.

Resumo Objetivo A pré-eclâmpsia (PE) é uma síndrome específica da gravidez caracterizada por níveis anormais de citocinas e fatores angiogênicos, que desempenham um papel no desenvolvimento da doença. Este estudo avaliou se os marcadores imunológicos estão associados à idade gestacional e à gravidade da doença em mulheres com pré-eclâmpsia. Métodos Noventa e cinco mulheres que desenvolveram PE foram estratificadas pela idade gestacional em PE pré-termo (< 37 semanas) e PE a termo (≥ 37 semanas de gestação) e comparadas quanto à gravidade da doença, bem como à concentração plasmática de fatores angiogênicos e citocinas. As concentrações de fator de crescimento placentário (PlGF), fator de crescimento endotelial vascular (VEGF), tirosina quinase solúvel semelhante a Fms (sFlt-1) e endoglina solúvel (sEng), bem como as citocinas, fator de necrose tumoral alfa (TNF- α) e interleucina 10 (IL-10), foram determinados porensaio de imunoabsorção enzimática (ELISA, na sigla em inglês). Resultados A comparação entre os grupos com pré-eclâmpsia mostrou maior porcentagem de casos graves em PE pré-termo (82,1%) do que em PE a termo (35,9%). Da mesma forma, as concentrações de TNF-α, sFlt-1 e sEng, bem como as razões TNF-α/IL-10 e sFlt-1/PlGF foram significativamente maiores no grupo de PE pré-termo. Em contraste, as concentrações de PlGF, VEGF e IL-10 foram significativamente menores em mulheres com PE pré-termo. Correlações negativas entre TNF-α e IL-10 (r = 0.5232) e entre PlGF e sFlt1 (r = 0.4158) foram detectadas no grupo de PE pré-termo. Conclusão Em gestantes com PE pré-termo, ocorre um desequilíbrio entre os marcadores imunológicos, com predomínio de fatores antiangiogênicos e TNF-α, associados a desfechos clínicos maternos adversos.

Progesterone and vitamin D downregulate the activation of the NLRP1/NLRP3 inflammasomes and TLR4-MyD88-NF-κB pathway in monocytes from pregnant women with preeclampsia.

This study evaluated the in vitro modulatory effect of progesterone (PG) and vitamin D (VD) on NLRP1/NLRP3 inflammasomes and TLR4/NF-κB pathway in monocytes from pregnant women with preeclampsia (PE). Monocytes from 20 preeclamptic and 20 normotensive (NT) pregnant women, and THP-1 cells were cultured with/without hyaluronan (HA), PG, or VD to determine gene and protein expression of TLR4 receptor, phosphorylated NF-κB, IκBα, TLR4, MYD88, NF-κB, NLRP1, NLRP3, caspase-1, IL-1ß, IL-18, TNF-α, and IL-10. Higher endogenous activation of inflammatory genes and higher protein expression of TLR4 and NF-κB was detected in monocytes of PE group and decreased after PG or VD treatment. Monocyte from PE stimulated with HA increased while treatment with PG or VD decreased the expression of genes and proteins related to the inflammasomes. THP-1 cells showed a similar immune response profile as monocytes from PE. These results demonstrate that PG and VD play an immunomodulatory role in monocyte activation.

Silibinin induces in vitro M2-like phenotype polarization in monocytes from preeclamptic women.

Preeclampsia (PE) is a pregnancy-specific syndrome featuring intense activation of circulating monocytes and an imbalance between pro- and anti-inflammatory cytokines. The present study evaluated the immunomodulatory effect of silibinin (Sb) on the expression of surface markers and the nuclear transcription factor NF-κB signalling pathway of monocytes from preeclamptic women. Monocytes were cultured with or without Sb, and the mean fluorescence intensity of the surface molecules TLR4, CD64, and CD163 as well as the intracellular transcription factors IκB-α and NF-κBp65 was analysed by flow cytometry. The concentration of cytokines in the monocyte culture supernatant was determined by cytometric bead array and ELISA immunoassay. The results showed that the in vitro treatment of monocytes from preeclamptic women with Sb downregulated the endogenous activation of NF-κB and the expression of surface receptors TLR4 and CD64, and reduced the synthesis of the pro-inflammatory cytokines interleukin 1 (IL-1ß), IL-6, IL-8, IL-12p70, IL-23, and tumour necrosis factor alpha (TNF-α) compared with cultures not treated with Sb. The presence of this flavonoid in monocyte cultures increased the expression of CD163 and IκBα and the release of IL-10 and transforming growth factor beta (TGF-ß) in the culture supernatants, polarising these cells from the M1-like profile to the M2-like profile. The anti-inflammatory activity of Sb on the NF-κB activation pathway and induction of cell polarisation to the M2 profile was confirmed by an in vitro assay using monocytes from healthy, non-pregnant women. Treatment of monocytes from preeclamptic women with Sb polarises the cells to the M2-like phenotype, suggesting that this flavonoid has an immunomodulatory effect on the sterile inflammation characteristic of PE.

Silibinin Downregulates the NF-κB Pathway and NLRP1/NLRP3 Inflammasomes in Monocytes from Pregnant Women with Preeclampsia.

Preeclampsia (PE) is a human pregnancy-specific syndrome with abnormal activation of cells from the innate immune system. The present study evaluated whether silibinin (SB) treatment of monocytes from preeclamptic women could modulate NLRP1 and NLRP3 inflammasomes as well as TLR4/NF-κB pathway activation. Peripheral blood monocytes from 20 preeclamptic and 20 normotensive (NT) pregnant women, as well as the THP-1 cell line, were cultured with or without monosodium urate (MSU) or SB. NLRP1, NLRP3, Caspase-1, TLR4, MyD88, NF-κB, IL-1ß, IL-18, TNF-α and IL-10 gene expression by monocytes was analysed by quantitative real-time polymerase chain reaction (qPCR), while inflammatory cytokine production and p65NF-κB activity were determined by enzyme-linked immunosorbent assays (ELISAs). TLR4/MyD88/NF-κB and NLRP1/NLRP3 inflammasomes pathways in THP-1 cells were evaluated by flow cytometry and western blot respectively. Compared with NT women, monocytes from preeclamptic women showed The Ethics Committee of the Botucatu Medical School approved the study (protocol number 2.333.216)higher endogenous activation of NLRP1/NLRP3 inflammasomes and the TLR4/NF-κB pathway as well as higher gene and protein expression of IL-1ß, IL-18 and TNF-α, and lower expression of IL-10. Monocyte stimulation with MSU increased inflammation-related genes as well as NF-κB activity. In vitro, SB treatment of monocytes from preeclamptic women reduced the basal activation of these cells by decreasing NLRP1/NLRP3 inflammasomes and p65NF-κB activity. THP-1 cells exhibited a similar immunological response profile to monocytes from preeclamptic women when cultured with or without MSU or SB. These results suggest uric acid participates in the systemic inflammatory response characteristic of preeclampsia and that in vitro SB treatment can modulate the sterile inflammation established in monocytes from preeclamptic women.

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.