Xin-Mei Liu

Activation of the epithelial Na + channel triggers prostaglandin E 2 release and production required for embryo implantation

Embryo implantation remains a poorly understood process. We demonstrate here that activation of the epithelial Na+ channel (ENaC) in mouse endometrial epithelial cells by an embryo-released serine protease, trypsin, triggers Ca2+ influx that leads to prostaglandin E2 (PGE2) release, phosphorylation of the transcription factor CREB and upregulation of cyclooxygenase 2, the enzyme required for prostaglandin production and implantation. We detected maximum ENaC activation, as indicated by ENaC cleavage, at the time of implantation in mice. Blocking or knocking down uterine ENaC in mice resulted in implantation failure. Furthermore, we found that uterine ENaC expression before in vitro fertilization (IVF) treatment is markedly lower in women with implantation failure as compared to those with successful pregnancy. These results indicate a previously undefined role of ENaC in regulating the PGE2 production and release required for embryo implantation, defects that may be a cause of miscarriage and low success rates in IVF.

FSH regulates fat accumulation and redistribution in aging through the Gαi/Ca2+/CREB pathway

Increased fat mass and fat redistribution are commonly observed in aging populations worldwide. Although decreased circulating levels of sex hormones, androgens and oestrogens have been observed, the exact mechanism of fat accumulation and redistribution during aging remains obscure. In this study, the receptor of follicle‐stimulating hormone (FSH), a gonadotropin that increases sharply and persistently with aging in both males and females, is functionally expressed in human and mouse fat tissues and adipocytes. Follicle‐stimulating hormone was found to promote lipid biosynthesis and lipid droplet formation; FSH could also alter the secretion of leptin and adiponectin, but not hyperplasia, in vitro and in vivo. The effects of FSH are mediated by FSH receptors coupled to the Gαi protein; as a result, Ca2+ influx is stimulated, cAMP‐response‐element‐binding protein is phosphorylated, and an array of genes involved in lipid biosynthesis is activated. The present findings depict the potential of FSH receptor‐mediated lipodystrophy of adipose tissues in aging. Our results also reveal the mechanism of fat accumulation and redistribution during aging of males and females.

Down-Regulation of S100A11, a Calcium-Binding Protein, in Human Endometrium May Cause Reproductive Failure

BACKGROUNDnLow expression levels of S100A11 proteins were demonstrated in the placental villous tissue of patients with early pregnancy loss, and S100A11 is a Ca2+-binding protein that interprets the calcium fluctuations and elicits various cellular responses.nnnOBJECTIVESnThe objective of the study was to determine S100A11 expression in human endometrium and its roles in endometrial receptivity and embryo implantation.nnnMETHODSnS100A11 expression in human endometrium was analyzed using quantitative RT-PCR, Western blot, and immunohistochemical techniques. The effects of S100A11 on embryo implantation were examined using in vivo mouse model, and JAr (a human choriocarcinoma cell line) spheroid attachment assays. The effects of endometrial S100A11 on factors related to endometrial receptivity and immune responses were examined. Using a fluorescence method, we examined the changes in cytosolic Ca2+ and Ca2+ release from intracellular stores in epidermal growth factor (EGF)-treated endometrial cells transfected with or without S100A11 small interfering RNA.nnnRESULTSnS100A11 was expressed in human endometrium. S100A11 protein levels were significantly lower in endometrium of women with failed pregnancy than that in women with successful pregnancy outcomes. The knockdown of endometrial S100A11 not only reduced embryo implantation rate in mouse but also had adverse effects on the expression of factors related to endometrial receptivity and immune responses in human endometrial cells. Immunofluorescence analysis showed that S100A11 proteins were mainly localized in endoplasmic reticulum. The EGF up-regulated endometrial S100A11 expression and promoted the Ca2+ uptake and release from Ca2+ stores, which was inhibited by the knockdown of S100A11.nnnCONCLUSIONSnEndometrial S100A11 is a crucial intermediator in EGF-stimulated embryo adhesion, endometrium receptivity, and immunotolerance via affecting Ca2+ uptake and release from intracellular Ca2+ stores. Down-regulation of S100A11 may cause reproductive failure.

Tunable deep-subwavelength superscattering using graphene monolayers

In this Letter, we theoretically propose for the first time that graphene monolayers can be used for superscatterer designs. We show that the scattering cross-section of the bare deep-subwavelength dielectric cylinder is markedly enhanced by six orders of magnitude due to the excitation of the first-order resonance of graphene plamons. By utilizing the tunability of the plasmonic resonance through tuning graphenes chemical potential, the graphene superscatterer works in a wide range of frequencies from several terahertz to tens of terahertz.

Cardiovascular and metabolic profiles of offspring conceived by assisted reproductive technologies: a systematic review and meta-analysis

OBJECTIVEnTo evaluate cardiovascular and metabolic features of offspring conceived by inxa0vitro fertilization/intracytoplasmic sperm injection (IVF-ICSI).nnnDESIGNnLiterature review and meta-analysis.nnnSETTINGnNot applicable.nnnPATIENT(S)nOffspring from IVF-ICSI versus natural conception.nnnINTERVENTION(S)nNone.nnnMAIN OUTCOME MEASURE(S)nSystolic and diastolic blood pressure (SBP and DBP), cardiovascular function, body mass index (BMI), and lipid and glucose profiles.nnnRESULT(S)nWe included 19 studies that had recruited 2,112 IVF-ICSI and 4,096 naturally conceived offspring, ranging from childhood to early adulthood. The blood pressure levels of IVF-ICSI offspring were statistically significantly higher than those of naturally conceived offspring (weighted mean differences and confidence intervals: 1.88xa0mm Hg [95% CI, 0.27, 3.49] for SBP and 1.51xa0mm Hg [95% CI, 0.33, 2.70] for DBP). In addition, cardiac diastolic function was suboptimal and vessel thickness was higher among IVF-ICSI offspring. Compared with the metabolism of naturally conceived offspring, IVF-ICSI offspring displayed comparable BMI, lower low-density lipoprotein cholesterol levels, and higher fasting insulin levels.nnnCONCLUSION(S)nChildren conceived by IVF-ICSI manifested a minor yet statistically significant increase in blood pressure without the clustering of increased BMI or impaired lipid metabolism by early adulthood. Our findings indicate a risk of cardiovascular disease among IVF-ICSI offspring, which calls for longer-term follow-ups and further investigation.

Cardiovascular Dysfunction in Offspring of Ovarian-Hyperstimulated Women and Effects of Estradiol and Progesterone: A Retrospective Cohort Study and Proteomics Analysis

CONTEXTnThe cardiovascular dysfunction in children born with assisted reproductive technologies has been of great concern. However, the association of ovarian hyperstimulation syndrome (OHSS), a complication of assisted reproductive technologies, with worse cardiovascular functions and underlying mechanism remains unknown.nnnOBJECTIVESnThe objective of the study was to assess the cardiovascular functions of children born to mothers with OHSS and investigate the underlying regulator(s).nnnDESIGN AND SETTINGnThis was a retrospective cohort recruited in a university hospital.nnnPARTICIPANTS AND METHODSnWe assessed the cardiovascular functions by Doppler echography in 42 children born to OHSS women, 34 children of mothers with non-OHSS in vitro fertilization, and 48 spontaneously conceived (SC) children (mean age ∼ 4.5 y). Groups were matched for gestational age at delivery and birth weight. An isobaric tag for relative and absolute quantitation-labeled proteomics analysis was performed with another set of umbilical arteries from OHSS and SC pregnancies (n = 3 for both groups).nnnRESULTSnChildren of OHSS mothers showed a significantly decreased mitral ratio of early to late mitral peak velocities, reduced systolic and diastolic diameters of common carotid arteries, and impaired flow-mediated dilation compared with non-OHSS in vitro fertilization and SC children. Intima-media thickness and arterial stiffness indices were similar in the three groups. In the proteomics study, 1640 proteins were identified from OHSS and SC umbilical arteries, and 40 differentially expressed proteins were selected for further analysis. Estradiol and progesterone were identified as activated upstream regulators.nnnCONCLUSIONSnChildren born to ovarian-hyperstimulated women displayed cardiovascular dysfunctions. The underlying mechanisms may involve the effects of supraphysiological estradiol and progesterone levels.

Altered thyroid hormone profile in offspring after exposure to high estradiol environment during the first trimester of pregnancy: a cross-sectional study

BackgroundThe increasing number of babies conceived by in vitro fertilization and embryo transfer (IVF-ET) shifts concern from pregnancy outcomes to long-time health of offspring. Maternal high estradiol (E2) is a major characteristic of IVF-ET and lasts throughout the first trimester of pregnancy. The fetal thyroid develops during this period and may thus be affected by exposure to the supra-physiological E2. The aim of this study is to investigate whether the high E2 maternal environment in the first trimester increases the risk of thyroid dysfunction in children born following IVF-ET.MethodsA cross-sectional survey design was used to carry out face-to-face interviews with consecutive children attending the hospital. A total of 949 singletons born after fresh embryo transfer (ET) (nu2009=u2009357), frozen ET (nu2009=u2009212), and natural conception (NC) (nu2009=u2009380), aged 3 to 10xa0years old, were included. All children were thoroughly examined. Meanwhile, another 183 newborns, including 55 fresh ET, 48 frozen ET, and 80 NC were studied. Levels of serum T3, FT3, T4, FT4, and TSH and levels of maternal E2 at different stages of the first trimester were examined.ResultsThe mean serum E2 levels of women undergoing fresh ET during the first trimester of pregnancy were significantly higher than those of the women undergoing frozen ET or following NC. The thyroid hormone profile, especially the levels of T4, FT4, and TSH, were significantly increased in 3- to 10-year-old children conceived by fresh ET compared to NC. The same tendency was confirmed in newborns. However, levels of T4 and TSH in the frozen ET group were nearer to that of the NC group. Furthermore, levels of T4 and FT4 in fresh ET were positively correlated with maternal serum levels of E2 during early pregnancy.ConclusionsThe maternal high E2 environment in the first trimester is correlated with increased risk of thyroid dysfunction. Frozen ET could reduce risks of thyroid damage in children conceived by IVF. Further studies are needed to confirm these findings and to better determine the underlying molecular mechanisms and clinical significance.Trial registrationChicCTR-OCC-14004682 (22-05-2014)

Lowering the high rate of caesarean delivery in China: an experience from Shanghai

To examine the trends of caesarean delivery (CD) after an intervention to lower the high rate of CD at a Chinese maternity hospital.

Ion/water channels for embryo implantation barrier.

Successful implantation involves three distinct processes, namely the embryo apposition, attachment, and penetration through the luminal epithelium of the endometrium to establish a vascular link to the mother. After penetration, stromal cells underlying the epithelium differentiate and surround the embryo to form the embryo implantation barrier, which blocks the passage of harmful substances to the embryo. Many ion/water channel proteins were found to be involved in the process of embryo implantation. First, ion/water channel proteins play their classical role in establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ions across the cell membrane. Second, most of ion/water channel proteins are regulated by steroid hormone (estrogen or progesterone), which may have important implications to the embryo implantation. Last but not least, these proteins do not limit themselves as pure channels but also function as an initiator of a series of consequences once activated by their ligand/stimulator. Herein, we discuss these new insights in recent years about the contribution of ion/water channels to the embryo implantation barrier construction during early pregnancy.

Follicle-stimulating hormone promotes age-related endometrial atrophy through cross-talk with transforming growth factor beta signal transduction pathway

It is widely believed that endometrial atrophy in postmenopausal women is due to an age‐related reduction in estrogen level. But the role of high circulating follicle‐stimulating hormone (FSH) in postmenopausal syndrome is not clear. Here, we explored the role of high circulating FSH in physiological endometrial atrophy. We found that FSH exacerbated post‐OVX endometrial atrophy in mice, and this effect was ameliorated by lowering FSH with Gonadotrophin‐releasing hormone agonist (GnRHa). In vitro, FSH inhibited endometrial proliferation and promoted the apoptosis of primary cultured endometrial cells in a dose‐dependent manner. In addition, upregulation of caspase3, caspase8, caspase9, autophagy‐related proteins (ATG3, ATG5, ATG7, ATG12 and LC3) and downregulation of c‐Jun were also observed in endometrial adenocytes. Furthermore, smad2 and smad3 showed a time‐dependent activation in endometrial cells which can be partly inhibited by blocking the transforming growth factor beta receptor II (TβRII). In conclusion, FSH regulated endometrial atrophy by affecting the proliferation, autophagy and apoptosis of endometrial cells partly through activation of the transforming growth factor beta (TGFβ) pathway.