Time filter

Source Type

Qingdao, China

Guo C.,Fudan University | Ni X.,Fudan University | Zhu P.,No. 401 Hospital | Li W.,Maternity and Infant Health Hospital of Changning District | And 2 more authors.
Reproduction | Year: 2010

Cytosolic phospholipase A2α (cPLA2α, now known as PLA2G4A) is the enzyme catalyzing the formation of the rate-limiting substrate, arachidonic acid, for prostaglandin (PG) synthesis. The increasing expression of PLA2G4A toward termgestation in human amnion fibroblasts is believed to be the crucial event in parturition. Human amnion fibroblasts produce cortisol, progesterone and express glucocorticoid receptor (GR), progesterone receptorA (PGRA) format term. The roles of progesterone and PGRA in the induction of PLA2G4A by cortisol via GR in the amnion fibroblasts remain largely unknown. Using cultured human term amnion fibroblasts, we found that cortisol induced the expression of PGRA, which was attenuated by inhibiting PG synthesis with indomethacin. Knockdown of PGRA expression or inhibition of endogenous progesterone production with trilostane significantly enhanced the induction of PLA2G4A by cortisol, whereas overexpression of PGRA attenuated the induction of PLA2G4A by cortisol. Although exogenous progesterone did not alter PLA2G4A expression under basal conditions, it attenuated cortisol-induced PLA2G4A expression at concentrations about tenfold higher, which might be achieved by competition with cortisol for GR. In conclusion, PGRA in the presence of endogenous progesterone is a transdominant repressor of the induction of PLA2G4A by cortisol. High level of progesterone may compete with cortisol for GR, thus further inhibiting the induction of PLA2G4A by cortisol. Moreover, increased PG synthesis by cortisol may feed back on the expression of PGRA leading to attenuation of cortisol-induced PLA2G4A expression. The above findings may be pertinent to the inconsistent effects of glucocorticoids on parturition in humans. © 2010 Society for Reproduction and Fertility.

Wang W.S.,Fudan University | Liu C.,Fudan University | Li W.J.,Maternity and Infant Health Hospital of Changning District | Zhu P.,No. 401 Hospital | And 3 more authors.
Placenta | Year: 2014

Introduction Increased estrogen production in placenta towards the end of gestation plays a pivotal role in the onset of human labor. Estrogen transforms myometrium from a quiescent to a contractile status. Glucocorticoids have been shown to induce estrogen production through the transcription factor specificity protein 1 (Sp1)-mediated induction of aromatase transcription upon elevation of cyclic adenosine mono-phosphate (cAMP) level in human placental syncytiotrophoblasts. However, it is unclear how glucocorticoids activate cAMP pathway thereby inducing aromatase expression in human placental syncytiotrophoblasts. Material and methods We investigated this issue in cultured primary human placental syncytiotrophoblasts prepared from placentas collected at term without labor. Results We demonstrated that cortisol (0.01-1 μM) dose-dependently increased corticotropin-releasing hormone (CRH) and human chorionic gonadotropin (hCG) α/β subunit expression and their production in the syncytiotrophoblasts. The induction of intracellular cAMP level, Sp1 expression, Sp1 enrichment at the aromatase promoter as well as aromatase expression by cortisol could be partially attenuated by either hCG antibody (1:100) or CRH receptor antagonist α-helical-CRH (1 μM), and further attenuated by combination of hCG antibody and α-helical-CRH. Conclusions Cortisol increases aromatase expression via induction of CRH and hCG production and subsequent elevation of cAMP level and enrichment of Sp1 at the aromatase promoter in human placental syncytiotrophoblasts. These findings may account for the parallel increases of cortisol and estrogen production prior to the onset of parturition. © 2013 Elsevier Ltd. All rights reserved.

Li X.Q.,Yangzhou University | Zhu P.,No. 401 Hospital | Myatt L.,University of Texas Health Science Center at San Antonio | Sun K.,Shanghai JiaoTong University | Sun K.,University of Texas Health Science Center at San Antonio
Placenta | Year: 2014

The pivotal role of glucocorticoids in the initiation of parturition has been very well documented in several domestic mammalian animal species. However the role of glucocorticoids in human parturition remains controversial mainly because of the absence of effect of synthetic glucocorticoids, given to promote fetal organ maturation in pregnant women with threatened preterm delivery, on the length of gestation. This article will review studies of glucocorticoids in human parturition and provide evidence for an important role of glucocorticoids in human parturition as well but a simultaneous high concentration of estrogen within the intrauterine tissues may be necessary for GCs to initiate parturition. The synthetic GCs dexamethasone and betamethasone pass through the placenta intact resulting in potent negative feedback on the fetal HPA axis and diminished production of DHEA from fetal adrenal glands for estrogen synthesis by the placenta. This may negate the effect of systemic administration of GCs on the induction of labor, especially in cases where the myometrium is not yet fully primed by estrogen. Endogenous glucocorticoids are inactivated by the placental 11β-HSD2 thus limiting the negative feedback of maternal cortisol on the fetal HPA axis and allowing the simultaneous rise of cortisol and estrogen levels towards the end of gestation. Therefore, endogenous glucocorticoids, particularly glucocorticoids produced locally in the intrauterine tissues may play an important role in parturition in humans by enhancing prostaglandin production in the fetal membranes and stimulating estrogen and CRH production in the placenta. © 2014 Elsevier Ltd. All rights reserved.

Wang W.,Shanghai JiaoTong University | Wang W.,Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics | Guo C.,University of Texas Health Science Center at San Antonio | Zhu P.,No. 401 Hospital | And 12 more authors.
Science Signaling | Year: 2015

The induction of cyclooxygenase-2 (COX-2) and subsequent production of prostaglandin E2 (PGE2) by cortisol in the amnion contrast with the effect of cortisol on most other tissues, but this proinflammatory effect of cortisol may be a key event in human parturition (labor). We evaluated the underlying mechanism activated by cortisol in primary human amnion fibroblasts. Exposure of the amnion fibroblasts to cortisol led to the activation of the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway, which induced the phosphorylation of the kinase SRC and STAT3 (signal transducer and activator of transcription 3). STAT3 interacted with the glucocorticoid receptor (GR) and the transcription factor CREB-1 (cAMP response element-binding protein 1) at the promoter of the gene encoding COX-2, which promoted the production of the secreted prostaglandin PGE2. PGE2 activates the prostaglandin receptors EP2 and EP4, which stimulate cAMP-PKA signaling. Thus, cortisol reinforced the activation of cAMP-PKA signaling through an SRC-STAT3-COX-2-PGE2-mediated feedback loop. Inhibiting STAT3, SRC, or the cAMP-PKA pathway attenuated the cortisol-stimulated induction of COX-2 and PGE2 production in amnion fibroblasts. In human amnion tissue, the amount of phosphorylated STAT3 correlated positively with that of cortisol, COX-2, and PGE2, and all were more abundant in tissue obtained after active labor than in tissue obtained from cesarean surgeries in the absence of labor. These results indicated that the coordinated recruitment of STAT3, CREB-1, and GR to the promoter of the gene encoding COX-2 contributes to the feed-forward induction of COX-2 activity and prostaglandin synthesis in the amnion during parturition.

Li J.,Shanghai University | Zhao J.,No. 401 Hospital | He C.,Shanghai University | Tong W.,Shanghai University | And 2 more authors.
Journal of Arthroplasty | Year: 2016

Background: This study was conducted to compare the blood loss during primary total hip arthroplasty (THA) between ankylosing spondylitis (AS) and hip osteoarthritis (OA). Methods: We reviewed 120 THAs in 68 patients comprising 3 groups: AS with total bony ankylosis of the hips (ASB), AS with stiff hips (ASS), and OA. Demographics, perioperative laboratory values, intraoperative data, blood loss, transfusion rate, transfusion reactions, surgical complications, hospitalization cost, and length of stay (LOS) were collected and analyzed among ASB, ASS, and OA groups. Results: The patients of the ASB and ASS groups were much younger and thinner than those of the OA group. There were no significant differences in the preoperative values of activated partial thromboplastin time, prothrombin time, and international normalized ratio among the 3 groups (all P > .05). The intraoperative blood loss, volume of drainage, hidden blood loss, transfusion rate, transfusion reactions, and hospitalization cost in the ASB group were significantly higher than in the other 2 groups, although not significantly different between the ASS and OA groups (P > .05). Conclusion: Both AS and OA can cause hyperosteogeny to the hips, but ASB patients have more serious symptoms in their affected hips. This may cause more blood loss in THA surgery because of bone surface bleeding. The reason that ASB patients suffered more blood loss may be related to the high difficulty and long duration of the operation. © 2016 Elsevier Inc.

Discover hidden collaborations