Activin signalling and pre-eclampsia: from genetic risk to pre-symptomatic biomarker.

Pre-eclampsia is a multi-system condition in pregnancy that is characterised by the onset of hypertension and proteinuria in women after the 20th week and it remains a leading cause of maternal and fetal mortality. Despite this the causative molecular basis of pre-eclampsia remains poorly understood. As a result, an intensive research effort has focused on understanding the molecular mechanisms involved in pre-eclampsia and using this information to identify new pre-symptomatic bio-markers of the condition. Activin A and its receptor, ACVR2A, have been extensively studied in this regard. Activin A is a member of the transforming growth factor (TGF)-ß superfamily that has a wide range of biological functions depending on the cellular context. Recent work has shown that polymorphisms in ACVR2A may be a genetic risk factor for pre-eclampsia. Furthermore, both placenta and serum levels of Activin A are significantly increased in pre-eclampsia suggesting that Activin A may be a possible biomarker for the condition. Here we review the latest advances in this field and link these with new molecular data that suggest that the oxidative stress and pro-inflammatory cytokine production seen in pre-eclampsia may result in increased placental Activin A secretion in an attempt to maintain placental function.

L-(+)-Ergothioneine Significantly Improves the Clinical Characteristics of Preeclampsia in the Reduced Uterine Perfusion Pressure Rat Model.

Preeclampsia is a multifactorial hypertensive disorder of pregnancy founded on abnormal placentation, and the resultant placental ischemic microenvironment is thought to play a crucial role in its pathophysiology. Placental ischemia because of fluctuations in the delivery of oxygen results in oxidative stress, and recent evidence suggests that mitochondrial dysfunction may be a prime mediator. However, large clinical trials of therapeutic antioxidants such as vitamins C and E for the treatment of preeclampsia have been disappointing. L-(+)-ergothioneine (ERG)-an unusual amino acid betaine derived from histidine-has important cytoprotective and antioxidant properties under conditions of high oxidative stress. In this study, we investigated the potential therapeutic effects of administration of ERG in the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia. ERG (25 mg/kg per day) was administered to rats on gestational day 11. On gestational day 14, RUPP surgery was performed, and on gestational day 19, blood pressure (mean arterial pressure) and fetal growth were measured. Production of mitochondria-specific H2O2 was analyzed in vivo in kidney samples. ERG ameliorated the hypertension (129±3 versus 115±4 mm Hg; P=0.01; n=8) and significantly increased pup weight in RUPP rats. ERG also significantly decreased circulating levels of antiangiogenic sFlt-1 (soluble fms-like tyrosine kinase-1) in RUPP rats (1367±245 pg/mL; P=0.04). Mitochondria-specific H2O2 (0.022±0.003 versus 0.029±0.001; MitoP/B ratio, n=3; P=0.05) was also significantly decreased in kidney tissue in RUPP rats treated with ERG. These data support the potential use of ERG for the treatment of preeclampsia.

Effect of L-Ergothioneine on the metabolic plasma profile of the RUPP rat model of pre-eclampsia.

INTRODUCTION: Pre-eclampsia is a major cause of maternal and fetal mortality and morbidity worldwide. Its pathophysiology remains unclear, but mitochondrial dysfunction and oxidative stress have been implicated. L-Ergothioneine is a naturally occurring, water-soluble betaine, that has demonstrated antioxidant properties. Using the reduced uterine perfusion pressure (RUPP) rat model of pre-eclampsia, this study aimed to define the plasma metabolic profile following treatment with L-Ergothioneine. METHODS: The effect of L-Ergothioneine (ET) treatment was explored using in vivo treatment in rats: Sham control (SC, n = 5), RUPP control (RC, n = 5), Sham +ET (ST, n = 5), RUPP +ET (RT, n = 5). Differential expression of plasma metabolites were obtained using untargeted liquid chromatography coupled to mass spectrometry. Statistical analysis was performed on normalised data comparing RC to SC, RT to RC, and RT to ST. Metabolites significantly altered (FDR < 0.05) were identified through database search. RESULTS: We report significantly lower levels of L-palmitoylcarnitine in RC compared to SC, a fatty acyl substrate involved in beta-oxidation in the mitochondria. We report that a metabolite that has been associated with oxidative stress (Glutamylcysteine) was detected at significantly higher levels in RT vs RC and RT vs ST. Five metabolites associated with inflammation were significantly lower in RT vs RC and three metabolites in RT vs ST, demonstrating the anti-inflammatory effects of ET in the RUPP rat model of pre-eclampsia. CONCLUSIONS: L-Ergothioneine may help preserve mitochondrial function by increasing antioxidant levels, and reducing inflammatory responses associated with pre-eclampsia. This study shows the potential of L-Ergothioneine as a treatment for pre-eclampsia.

Activation of a TLR9 mediated innate immune response in preeclampsia.

Preeclampsia is a multisystemic disorder leading to the development of a placental ischemic microenvironment with a resultant increase in oxidative stress. There is evidence that mitochondrial dysfunction and the innate immune system both play a role in the pathophysiology of this disease. Mitochondrial DAMPs such as mtDNA bind specific pattern recognition receptors such as Toll-like receptor 9 (TLR9) on the endosomal surface of immune cells, in particular neutrophils, subsequently activating them and triggering an innate response. We hypothesised that the exaggerated innate immune response seen in preeclampsia is provoked by dysfunctional mitochondria. Here we provide evidence that TLR9 activity is significantly increased at time of disease in women with preeclampsia. Furthermore, we show activation of neutrophil markers, Calprotectin, Myeloperoxidase (MPO), and IL-8 are significantly increased at time of disease compared to uncomplicated pregnancies. This research supports a potential role of TLR9 activation of an innate immune response evident in preeclampsia which may possibly be initially triggered by dysfunctional mitochondria.

Magnesium sulphate prevents lipopolysaccharide-induced cell death in an in vitro model of the human placenta.

OBJECTIVES: To determine if magnesium sulphate (MgSO4) prevents lipopolysaccharide (LPS)-induced cell death in an in vitro model of the human placenta. STUDY DESIGN: BeWo choriocarcinoma cells were treated with increasing concentrations of LPS (10-1000ng/ml) and MgSO4 ranging from 1 mM to 100 mM for 24 or 48h. For co-treatments, cells were pre-treated with 1mM MgSO4 for 1h and 200ng/ml LPS was then added for the remaining 48h. To assess viability an MTT assay was carried out along with nuclear staining to assess pyknotic nuclei. The expression of the pro-inflammatory cytokine TNF-α was examined by real-time PCR. RESULTS: MgSO4 had a dose dependent effect of cell viability with a narrow therapeutic window. MgSO4 (1mM) protected against adverse effects of LPS on cell viability by preventing LPS-induced decreases in cell viability (MTT assay) and protecting against LPS-induced pyknotic changes in nuclear membrane. MgSO4 also inhibited the elevated TNF-α mRNA expression induced by LPS. CONCLUSIONS: MgSO4 preserves BeWo cell viability following an inflammatory insult and reduces the mRNA expression of the inflammatory cytokine TNF-α. These data elucidate a potential therapeutic pathway by which MgSO4 may be protective in pre-eclampsia.