High Levels of Tumor Necrosis Factor-Alpha Reduce Placental Aquaporin 3 Expression and Impair in vitro Trophoblastic Cell Migration.

Placentas from preeclamptic women display augmented tumor necrosis factor-alpha (TNF-α) levels with reduced expression of aquaporin 3 (AQP3). However, whether TNF-α modulates AQP3 expression remains to be elucidated. We hypothesize that elevated levels of TNF-α reduce AQP3 expression and negatively impact trophoblastic cell migration. Spontaneously hypertensive rats (SHRs) and Wistar rats (14-16 weeks) were divided into hypertensive and normotensive groups, respectively. Systolic blood pressure (SBP) was measured, and animals mated. In a third group, pregnant SHRs were treated with a TNF-α antagonist, etanercept (0.8 mg/kg, subcutaneously) on days 0, 6, 12, and 18 of pregnancy. Placentas were collected on the 20th day of pregnancy. Human placental explants, from normotensive pregnancies, were incubated with TNF-α (5, 10, and 20 ng/ml) and/or etanercept (1 µg/ml). Swan 71 cells were incubated with TNF-α (10 ng/ml) and/or etanercept (1 µg/ml) and subjected to the wound healing assay. AQP3 expression was assessed by Western blot and TNF-α levels by ELISA. SBP (mmHg) was elevated in the hypertensive group, and etanercept treatment reduced this parameter. Placental TNF-α levels (pg/ml) were higher in the hypertensive group. AQP3 expression was reduced in the hypertensive group, and etanercept treatment reversed this parameter. Explants submitted to TNF-α exposition displayed reduced expression of AQP3, and etanercept incubation reversed it. Trophoblastic cells incubated with TNF-α showed decreased cell migration and reduced AQP3 expression, and etanercept incubation ameliorated it. Altogether, these data demonstrate that high TNF-α levels negatively modulate AQP3 in placental tissue, impairing cell migration, and its relationship in a pregnancy affected by hypertension.

The limited knowledge of placental damage due to neglected infections: ongoing problems in Latin America.

The placenta works as a selective barrier, protecting the fetus from potential infections that may affect the maternal organism during pregnancy. In this review, we will discuss several challenging infections that are common within Latin American countries and that may affect the maternal-fetal interface and pose risks to fetal development. Specifically, we will focus on emerging infectious diseases including the arboviruses, malaria, leishmaniasis, and the bacterial foodborne disease caused by Shiga toxin-producing Escherichia coli. We will also highlight some topics of interest currently being studied by research groups that comprise an international effort aimed at filling the knowledge gaps in this field. These topics address the relationship between exposure to microorganisms and placental abnormalities, congenital anomalies, and complications of pregnancy. ABBREVIATIONS: ADE: antibody-dependent enhancement; CCL2: monocyte chemoattractant protein-1; CCL3: macrophage inflammatory protein-1 α; CCL5: chemokine (C-C motif) ligand 5; CHIKV: chikungunya virus; DCL: diffuse cutaneous leishmaniasis; DENV: dengue virus; Gb3: glycolipid globotriaosylceramyde; HIF: hypoxia-inducible factor; HUS: hemolytic uremic syndrome; IFN: interferon; Ig: immunoglobulins; IL: interleukin; IUGR: intrauterine growth restriction; LCL: localized cutaneous leishmaniasis; LPS: lipopolysaccharid; MCL: mucocutaneous leishmaniasis; NO: nitric oxide; PCR: polymerase chain reaction; PGF: placental growth factor; PM: placental malaria; RIVATREM: Red Iberoamericana de Alteraciones Vasculares em transtornos del Embarazo; sVEGFR: soluble vascular endothelial growth factor receptor; STEC: shiga toxin-producing Escherichia coli; stx: shiga toxin protein; TNF: tumor necrosis factor; TOAS: T cell original antigenic sin; Var2CSA: variant surface antigen 2-CSA; VEGF: vascular endothelial growth factor; VL: visceral leishmaniasis; WHO: world health organization; YFV: yellow fever virus; ZIKV: Zika virus.

Leptin upregulates aquaporin 9 expression in human placenta in vitro.

Aquaporins are integral membrane proteins that have permeability functions in many tissues. Aquaporin 9 may transport not only water but also small molecules, such as glycerol, monocarboxylates, purines and pyrimidines. Aquaporin 9 is expressed in syncytiotrophoblast of human term placenta, and it may contribute to the embryonic/fetal growth and survival. We have previously found that Aquaporin 9 expression levels seem to be increased in placenta from gestational diabetes. Since leptin plasma levels and leptin expression are increased in placenta from gestational diabetes, we aimed to study the possible role of leptin on Aquaporin 9 expression in human placenta in vitro. The present work shows that leptin produces a dose-dependent increase of Aquaporin 9 expression, resulting in an increase in Aquaporin-9 protein in human trophoblast explants.

Niveles de ácido úrico sérico y riesgo de desarrollar preeclampsia

Si bien se conoce que existe una asociación entre los niveles elevados de ácido úrico y la preeclampsia, el debate sobre su aplicación clínica aún está abierto. Nuestro objetivo fue estudiar la utilidad del dosaje periódico del ácido úrico sérico durante el embarazo para identificar gestantes con mayor riesgo de desarrollar preeclampsia. Realizamos un estudio retrospectivo en gestantes primíparas: 79 normotensas y 79 con preeclampsia atendidas en el Hospital Nacional Posadas durante el año 2010. Se analizaron los niveles séricos de ácido úrico, creatinina y urea, y los datos de proteinuria de las historias clínicas de las mujeres embarazadas. Los niveles de ácido úrico fueron similares en ambos grupos durante la primera mitad de la gestación. Sin embargo, a partir de la semana 20, el ácido úrico se incrementó 1.5 veces en gestantes preeclámpticas, sin cambios en la uremia y creatininemia, descartándose así el compromiso renal. Además, encontramos que niveles más altos de ácido úrico se correlacionaban con bajo peso del recién nacido. También vimos que las gestantes con antecedentes familiares de hipertensión eran más propensas a desarrollar esta condición. Por otro lado, no observamos una relación directa ni con el sexo fetal ni con el tiempo de aparición de los síntomas clínicos. Estos hallazgos sugieren que los cambios en las concentraciones de ácido úrico se deberían a alteraciones en los estadios iniciales de la preeclampsia. Por ello, la monitorización de los niveles del mismo durante el embarazo podría contribuir al abordaje precoz de este desorden gestacional.

It is well known that preeclampsia is associated to high uric acid levels, but the clinical assessment of this relationship is still under consideration. Our research was to evaluate if periodic doses of uric acid during pregnancy might help to identify a high risk group prior to the onset of preeclampsia. We conducted a retrospective investigation in 79 primary gestates with normal blood pressure and 79 women with preeclampsia who were assisted at Hospital Nacional Posadas during 2010. Serum uric acid levels, creatininemia, uremia, and proteinuria data from the clinical records of the pregnant women were considered. Uric acid levels were similar in both groups during the first half of gestation. However, as of the 20th week, uric acid increased 1.5-times in preeclamptic women with no changes in creatinine and urea, confirming that these patients had no renal complications. Furthermore, we noted that higher levels of uric acid correlated with low birth weight. We also observed that pregnant women with a family history of hypertension were more likely to develop this condition. Moreover, we did not find a direct relationship with the fetal sex or the appearance of clinical symptoms. The analytical evidence suggests that changes in uric acid concentrations may be due to metabolic alterations at the initial stages of preeclampsia. Therefore, we propose that monitoring levels of uric acid during pregnancy might contribute to the early control of this condition.

High levels of human chorionic gonadotropin (hCG) correlate with increased aquaporin-9 (AQP9) expression in explants from human preeclamptic placenta.

Trophoblastic abnormalities have a central role in the pathophysiology of preeclampsia, and some placental hormones, such as human chorionic gonadotropin (hCG), could affect the placental function. Here, we hypothesized that the elevated serum levels of hCG may be involved in the increased aquaporin-9 (AQP9) protein expression in preeclamptic placentas via adenosine 3('),5(')-cyclic phosphate (cAMP) pathways. Normal placental explants were cultured with different concentrations of recombinant hCG or 8-Br-cAMP, a potent analogue of cAMP. We evaluated AQP9 protein expression and localization. After both treatments, we localized AQP9 in the apical membrane of syncytiotrophoblast and in the cytoplasm. We also observed a concentration-dependent effect on AQP9 protein expression. In addition, water uptake increased 1.6-fold in explants treated with hCG. Our results suggest that hCG may increase AQP9 protein expression and functionality via cAMP pathways. Although, in preeclamptic placentas high levels of hCG may upregulate AQP9 protein expression, AQP9 functionality was reduced possibly by other factors.

Ionic currents in multidrug resistant K562 human leukemic cells.

In this study, the expression and functional characterization of currents through the CFTR (cystic fibrosis transmembrane regulator) and ORCC (outwardly rectifying chloride channels) were determined in wild-type K562 chronic human leukemia cells (K562-WT) and in its resistant counterpart, the vincristine resistant cell line (K562-Vinc). Expression of the CFTR and MDR1 (multidrug resistant) gene products was determined by a semi-quantitative RT-PCR protocol. The amplified products in K562-WT and K562-Vinc showed two bands corresponding to CFTR and MDR1. MDR1 mRNA increased by 20-fold in K562-Vinc whereas no change in CFTR mRNA levels was observed. CFTR and ORCC channel activity were measured with a whole cell configuration of the patch clamp technique. Forskolin (40 microM n activator of adenylate cyclase, added to the extracellular side increased the current in both cell lines. A fraction of the activated whole cell currents was inhibited by 500 microM 4,4-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS) and subsequent addition of 500 microM diphenylamine-2-carboxylate (DPC plus DIDS) further inhibited the remaining currents. The levels of forskolin-activated currents and subsequent blockade were similar in both cell lines. The effect of forskolin was prevented in cells previously exposed to 500 microM DPC. The effects of DIDS and DPC on the forskolin-activated whole cell currents support the idea that both CFTR and ORCC are generating a significant fraction of these currents with DIDS inhibiting ORCC currents and DPC inhibiting CFTR currents when the blockers are added one after another to the extracellular side. Finally, we show that exposure of K562 cells to vincristine which results in the over expression of MDR1 is not accompanied by a significant down regulation of CFTR as in other cells.

CFTR in K562 human leukemic cells.

In this study, the expression and functional characterization of CFTR (cystic fibrosis transmembrane regulator) was determined in K562 chronic human leukemia cells. Expression of the CFTR gene product was determined by RT-PCR and confirmed by immunohistochemistry and Western blot analysis. Functional characterization of CFTR Cl- channel activity was conducted with patch-clamp techniques. Forskolin, an adenylyl cyclase activator, induced an anion-selective channel with a linear current-voltage relationship and a single-channel conductance of 11 pS. This cAMP-activated channel had a Pgluconate/PCl or PF/PCl perm-selectivity ratio of 0.35 and 0.30, respectively, and was inhibited by the CFTR blocker glibenclamide and the anti-CFTR antibody MAb 13-1, when added to the cytoplasmatic side of the patch. Glibenclamide decreased the open probability increasing the frequency of open-to-closed transitions. Addition of 200 microM DIDS caused an irreversible block of the channels when added to the cytosolic side of inside-out patches. These and other observations indicate a widespread distribution of CFTR gene expression and suggest that this channel protein may function in most human cells to help maintain cellular homeostasis.