Increased levels of soluble fms-like tyrosine kinase-1 are associated with adverse outcome in pregnant women with COVID-19.

OBJECTIVE: In addition to the lungs, the placenta and the endothelium can be affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) are markers of endothelial dysfunction and could potentially serve as predictors of severe coronavirus disease 2019 (COVID-19). We aimed to investigate the association of serum concentrations of sFlt-1 and PlGF with the severity of COVID-19 in pregnancy. METHODS: This was a prospective cohort study carried out in a tertiary care hospital in Mexico City, Mexico. Symptomatic pregnant women with a positive reverse-transcription quantitative polymerase chain reaction test for SARS-CoV-2 infection who fulfilled the criteria for hospitalization were included. The primary outcome was severe pneumonia due to COVID-19. Secondary outcomes were intensive care unit (ICU) admission, viral sepsis and maternal death. sFlt-1 levels were expressed as multiples of the median (MoM). The association between sFlt-1 and each adverse outcome was explored by logistic regression analysis, adjusted for gestational age for outcomes occurring in more than five patients, and the predictive performance was assessed by receiver-operating-characteristics-curve analysis. RESULTS: Among 113 pregnant women with COVID-19, higher sFlt-1 MoM was associated with an increased probability of severe pneumonia (adjusted odds ratio (aOR), 1.817 (95% CI, 1.365-2.418)), ICU admission (aOR, 2.195 (95% CI, 1.582-3.047)), viral sepsis (aOR, 2.318 (95% CI, 1.407-3.820)) and maternal death (unadjusted OR, 5.504 (95% CI, 1.079-28.076)). At a 10% false-positive rate, sFlt-1 MoM had detection rates of 45.2%, 66.7%, 83.3% and 100% for severe COVID-19 pneumonia, ICU admission, viral sepsis and maternal death, respectively. PlGF values were similar between women with severe and those with non-severe COVID-19 pneumonia. CONCLUSION: sFlt-1 MoM is higher in pregnant women with severe COVID-19 and has the capability to predict serious adverse pregnancy events, such as severe pneumonia, ICU admission, viral sepsis and maternal death. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Progesterone suppresses the lipopolysaccharide-induced pro-inflammatory response in primary mononuclear cells isolated from human placental blood.

Progesterone is an essential hormone that induces deep immune adaptations favoring pregnancy maintenance. We aimed at evaluating the effects of progesterone on the synthesis of pro- and anti-inflammatory cytokines by mononuclear cells isolated from human placental blood stimulated with lipopolysaccharide, emulating an infection-inflammation environment. Mononuclear cells isolated form human placental blood were obtained from nine women undergoing elective cesarean delivery at term (not in labor), isolated by density gradient sedimentation, cultured and co-stimulated with lipopolysaccharide (500 ng/ml) from Escherichia coli in the presence or not of progesterone (0.01, 0.1, or 1.0 µM) for 24 h. Culture supernatants were assayed for pro-inflammatory (IL-1ß, TNFα, IL-6), anti-inflammatory (IL-10) cytokines, chemokines (IL-8, MIP-1α) and total MMP-9 by ELISA. In comparison with basal conditions, lipopolysaccharide treatment induced IL-1ß, TNFα, IL-6, IL-8, MIP-1α, and MMP-9 synthesis. lipopolysaccharide co-treatment with progesterone significantly decreased the bacterial endotoxin-induced IL-1ß, TNF-α, IL-6, IL-8, and MIP-1α secretion. In contrast, co-treatment with progesterone increased the level of IL-10 secreted to the culture medium. The present results support the concept that progesterone can modulate--partially--the inflammatory response of professional immune cells isolated from placental blood. Therefore, progesterone might be part of the natural compensatory mechanism that limits the cytotoxic effects associated with an intrauterine infection process during gestation.

In vitro progesterone modulation on bacterial endotoxin-induced production of IL-1ß, TNFα, IL-6, IL-8, IL-10, MIP-1α, and MMP-9 in pre-labor human term placenta.

BACKGROUND: During human pregnancy, infection/inflammation represents an important factor that increases the risk of developing preterm labor. The purpose of this study was to determine if pre-treatment with progesterone has an immunomodulatory effect on human placenta production of endotoxin-induced inflammation and degradation of extracellular matrix markers. METHODS: Placentas were obtained under sterile conditions from pregnancies delivered at term before the onset of labor by cesarean section. Explants from central cotyledons of 10 human placentas were pre-treated with different concentrations of progesterone (0.01, 01, 1.0 µM) and then stimulated with 1000 ng/mL of LPS of Escherichia coli. Cytokines TNFα, IL-1ß, IL-6, IL-8, MIP-1α, IL-10 concentrations in the culture medium were then measured by specific ELISA. Secretion profile of MMP-9 was evaluated by ELISA and zymogram. Statistical differences were determined by one-way ANOVA followed by the appropriate ad hoc test; P < 0.05 was considered statistically significant. RESULTS: In comparison to the explants incubated with vehicle, the LPS treatment led to a significant increase in the level of all cytokines. In comparison to the explants treated only with LPS, pre-treatment with 0.01-1.0 µM progesterone significantly blunted (73, 56, 56, 75, 25, 48 %) the secretion of TNF-α, IL-1ß, IL-6, IL-8, MIP-1α, IL-10, respectively. The MMP-9 induced by LPS treatment was inhibited only with the highest concentration of progesterone. Mifepristone (RU486) blocked the immunosuppressive effect of progesterone. CONCLUSIONS: The present results support the concept that progesterone could be part of the compensatory mechanism that limits the inflammation-induced cytotoxic effects associated with an infection process during gestation.

Evidence of an immunosuppressive effect of progesterone upon in vitro secretion of proinflammatory and prodegradative factors in a model of choriodecidual infection.

OBJECTIVE: To evaluate whether progesterone (P4) is able to modulate the secretion of tumour necrosis factor α (TNF-α), interleukin-1ß (IL-1ß), IL-6, IL-8, IL-10 and matrix metalloproteinase-9 (MMP-9) after choriodecidual stimulation with lipopolysaccharide (LPS). DESIGN: Chorioamnionitis-elicited preterm delivery is associated with an uncontrolled secretion of proinflammatory cytokines that may induce MMPs, which modify the fine immunological and structural equilibrium at the fetal-maternal interface. SETTING: Instituto Nacional de Perinatología 'Isidro Espinosa de los Reyes', Mexico City. SAMPLE: Twelve human fetal membranes at term from healthy patients were placed in a two-chamber culture system. METHODS: Choriodecidual and amniotic regions were preincubated with 1.0, 0.1, or 0.01 µmol/l P4 for 24 hours; after which the choriodecidual region was costimulated with 1000 ng/ml of LPS for 24 hours. MAIN OUTCOME MEASURES: Descriptive statistics were obtained for each variable. Data distribution was tested for normality using Kolmogorov-Smirnoff and Shapiro-Wilk tests. When distribution was normal, Student's t test was used to analyse for differences among groups. Mann-Whitney's U test was used when data were not normally distributed. RESULTS: Pretreatment with 1.0 µmol/l P4 significantly blunted the secretion of TNF-α, IL-1ß, IL-6, IL-8 and IL-10. MMP-9 was inhibited with 0.1 µmol/l P4. Mifepristone (RU486) blocked the immunosuppressive effect of P4, suggesting a P4 effect mediated by its receptor. CONCLUSION: These results offer evidence to support the concept that P4 can protect the fetal-placental unit through a compensatory mechanism that partially limits the secretion of proinflammatory and prodegradative modulators.

PP134. l-Arginine supplementation induces the expression of genes related to antioxidant defense in cultures of human vascular endothelial cells: Protective role for preeclampsia.

INTRODUCTION: Recently, it has been proposed that supplementation with l-Arginine reduces the incidence of preeclampsia in high risk women, but the molecular mechanisms involved in the protective effect need to be determined. In addition, a critical role of l-Arginine in endothelial cell survival during oxidative stress, and the participation of neutrophils in the induction of oxidative stress during preeclampsia have been suggested. OBJECTIVES: To address if supplementation with l-arginine provides antioxidant defense in human vascular endothelial cells. METHODS: Human vascular endothelial cells (HUVECs) were isolated from umbilical cord veins obtained from healthy women underwent cesarean sections at term, with no evidence of hypertension disorders through the pregnancy. HUVECs were cultured in EndoGro media with LS supplement kit and 1% antibiotic with (n=10) or without 200uM l-Arginine (n=10). Confluent HUVECs were stimulated with neutrophils activated with 50umol/L arachidonic acid (1:16 ratio of neutrophil/cells). After incubation, cells were rinsed in PBS and harvested for RNA and protein extraction. Reverse transcription was performed using the RT(2) First Strand kit, and expression gene profiling was generated using the RT(2) Profiler PCR Array Human Oxidative Stress and Antioxidant Defense that includes the expression profile of 84 genes related to the oxidative pathway. Expression results were analyzed with the RT(2) Profiler PCR Array Data Analysis Template v3.0 and two different lists of fold change in gene expression were generated: (1) HUVEC+neutrophils vs HUVEC+l-Arginine + neutrophils and (2) HUVEC vs HUVEC+neutrophils. Validation of the expression assays was performed using western blots or ELISAS for proteins expressed by selected genes. RESULTS: Fold up- or down gene regulation are shown in Table 1. Forty six genes involved in oxidative stress defense were significantly up-regulated in HUVECs supplemented with l-arginine when were exposed to neutrophils. Interestingly, almost the same genes were down-regulated in non-supplemented HUVECs after neutrophil exposure. CONCLUSION: Supplementation with l-Arginine upregulates the expression of genes related to antioxidant defense in primary cultures of endothelial cells. This finding provides a novel insight about the molecular mechanisms involved in the protective role of l-Arginine during preeclampsia.