Removal of hydrosalpinges increases endometrial leukaemia inhibitory factor (LIF) expression at the time of the implantation window

BACKGROUND: The presence of hydrosalpinges is associated with lower implantation and pregnancy rates in women undergoing IVF-embryo transfer, while salpingectomy improves these parameters. Although the mechanism by which hydrosalpinges affects fertility is not entirely understood, an adverse effect on endometrial receptivity has been postulated. In this study, we hypothesized that the adverse effects of hydrosalpinges on fertility may be in part mediated by inappropriate endometrial expression of leukaemia inhibitory factor (LIF), a cytokine implicated in implantation. METHODS: In order to test our hypothesis, we prospectively examined the expression of LIF during the window of implantation in the endometrium of infertile women (n = 10) with hydrosalpinges prior to and following salpingectomy and of fertile controls (n = 10) by Western blotting and immunohistochemistry. RESULTS: LIF expression was significantly lower in infertile women with hydrosalpinges compared with fertile controls (P < 0.05). Salpingectomy resulted in an increase in LIF expression in eight out of 10 women with hydrosalpinges. LIF levels were increased by 231 +/-49% (mean +/- SEM) following salpingectomy. Immunohistochemical analysis confirmed the Western blot findings. The increased LIF immunoreactivity was predominantly localized to luminal and glandular epithelial cells. CONCLUSIONS: Our findings suggest that observed benefit from salpingectomy in infertile women with hydrosalpinges may be in part mediated by the up-regulation of endometrial LIF expression.     

Mouse blastocysts release a lipid which activates anandamide hydrolase in intact uterus

Anandamide (N-arachidonoylethanolamine, AEA) is a major endocannabinoid, known to impair mouse pregnancy and embryo development and to induce apoptosis in blastocysts. Here we show that mouse blastocysts rapidly (within 30 min of culture) release a soluble compound, that increases by approximately 2.5-fold the activity of AEA hydrolase (fatty acid amide hydrolase, FAAH) present in the mouse uterus, without affecting FAAH gene expression at the translational level. This "FAAH activator" was produced by both trophoblast and inner cell mass cells, and its initial biochemical characterization showed that it was fully neutralized by adding lipase to the blastocyst-conditioned medium (BCM), and was potentiated by adding trypsin to BCM. Other proteases, phospholipases A(2), C or D, DNAse I or RNAse A were ineffective. BCM did not affect the AEA-synthesizing phospholipase D, the AEA-binding cannabinoid receptors, or the selective AEA membrane transporter in mouse uterus. The FAAH activator was absent in uterine fluid from pregnant mice and could not be identified with any factor known to be released by blastocysts. In fact, platelet-activating factor inhibited non-competitively FAAH in mouse uterus extracts, but not in intact uterine horns, whereas leukotriene B(4) or prostaglandins E(2) and F(2)alpha had no effect. Overall, it can be suggested that blastocysts may protect themselves against the noxious effects of uterine endocannabinoids by locally releasing a lipid able to cross the cell membranes and to activate FAAH. The precise molecular identity of this activator, the first ever reported for FAAH, remains to be elucidated.     

Implantation, interception and contraception

The factors involved in post-fertilization events leading toimplantation in mammals are discussed with special referenceto potential forms of interception. The stages of embryonicgrowth until implantation are considered initially. The growthand differentiation of the uterine endometrium is then described,followed by the events occurring during the apposition and invasionof the implanting embryo. Several potential approaches to newforms of interception are considered, and the advantages anddisadvantages of each of them are evaluated. Among them, newvaccines against the zona pellucida, inactivation of the secretionsof the blastocyst, hatching, the activity of the pinopodes,and the endometrial proteins produced in the secretory phaseseem to offer various and varied targets. Some existing methodsof fertility regulation may act by affecting these stages ofdevelopment, e.g. RU486 may interfere with pinopod function.Various physiological and embryonic consequences of interferingwith these stages of pregnancy are discussed.     

Differentiation of endometrial stromal cells in vitro: down-regulation of suppression of the cell cycle inhibitor p57 by HOXA10?

Decidualization is a critical step during embryo implantation that is characterized by the differentiation of endometrial stromal cells (ESC) into decidua cells. However, the mechanism of differentiation remains largely unknown. Previously, it has been shown that the null function of homeo box A10 (HOXA10) causes defects in both implantation and decidualization, suggesting that the HOXA10 signalling pathway is likely to be involved in uterine decidualization. In the present study, we determined the expression and subcellular distribution of HOXA10 and its downstream molecule, p57, in ESC during in vitro decidualization induced by a combination of 8-bromo-cAMP and medroxyprogesterone acetate. We demonstrated that the HOXA10 was down-regulated while in contrast, p57 was up-regulated in the process of decidualization. Immunocytochemistry and transient expression of the HOXA10 tagged with green fluorescence protein revealed that there were no differences in the HOXA10 subcellular localization between the induced and non-induced ESC. Our results suggest that the down-regulation of HOXA10 may contribute to increased p57 and that up-regulation of p57 likely plays an important role in ESC differentiation in the process of decidualization. The progesterone receptor pathway may participate in promoting ESC to exit the cell cycle and enter differentiation.     

Secretory role for human uterodomes (pinopods): secretion of LIF

The differentiation of human endometrial epithelium is a dynamic event, which occurs throughout the menstrual cycle in preparation for pregnancy. The appearance of uterodomes (pinopods) in this regard was first introduced in rodents with an established pinocytotic function, whereas little evidence was available in humans in this context. This study was undertaken to identify the potential physiological roles of uterodomes in the implantation process. To address this, endometrial biopsies from early, mid- and late luteal phases of the menstrual cycle of 23 fertile female patients with regular menses were used. Scanning and transmission electron microscopies (SEM and TEM) as well as immunofluorescence and immunogold TEM were performed to study the morphological changes and the expression pattern of leukaemia inhibitory factor (LIF) at uterodomes. Our results illustrated a high level of LIF expression in the human uterodomes, which was colocalized with the well-known biochemical markers of exocytosis, including syntaxin-1, 25-kDa synaptosomal protein (SNAP-25) and vesicle-associated membrane protein-2 (VAMP-2). Our morphological and immunocytochemical findings illustrated a secretory function for human uterodomes for the first time. In conclusion, this novel function for uterodomes provides an important clue in detection of their physiological function(s) during the process of the plasma membrane transformation.     

Uterine contractility decreases at the time of blastocyst transfers

High-frequency uterine contractions at the time of non-cavitating embryo transfer influence adversely IVF-embryo transfer outcome. This prompted us to quantify prospectively the possible decline in uterine contraction frequency occurring during later stages of the luteal phase of ovarian stimulation, up to the time of blastocyst transfers, in 43 IVF-embryo transfer candidates. Contractility was assessed on the day of human chorionic gonadotrophin (HCG) administration, 4 days after HCG (non-cavitating embryo transfer; HCG + 4), and 7 days after HCG (blastocyst transfers; HCG + 7). For this, 2 min sagittal uterine scans were obtained by ultrasound and digitized with a computerized system for the assessment of uterine contraction frequency. Our results indicated that a slight, yet significant, decrease in uterine contraction frequency, observed from the day of HCG (4.4 +/- 0.2 contractions/min) to HCG + 4 (3.5 + 0.2 contractions/min), was followed by a more pronounced, additional decrease between HCG + 4 and HCG + 7 (1.5 +/- 0.2 contractions/min; P < 0.001). In conclusion, during the luteal phase of ovarian stimulation, uterine contractility decreases progressively, and reaches a nearly quiescent status 7 days after HCG administration, at the time of blastocyst transfers. It is possible that such a uterine relaxation assists blastocyst implantation.     

Continuous administration of gonadotrophin-releasing hormone agonist during the luteal phase in IVF

BACKGROUND: It has been reported that ceasing the administration of gonadotrophin-releasing hormone (GnRH) agonist causes a profound suppression of circulating serum gonadotrophins. A comparative prospective and randomized study was conducted to investigate the effect of continuous administration of GnRH agonist during the luteal phase in an ovarian stimulation programme for IVF. METHODS: GnRH agonist was administered intranasally from the midluteal phase of the previous cycle, and pure FSH administration started on cycle day 7. In the continuous-long protocol (cL) group (n = 161 ), GnRH agonist administration was continued until 14 days after oocyte retrieval. In the long protocol (L) group (n = 158 ), GnRH agonist was administered until the day before human chorionic gonadotrophin (HCG) administration. RESULTS: The implantation rate and live birth rate per unit of transferred embryos were significantly higher in the cL group than the L group (P < 0.05 ). Serum LH and FSH concentrations on the day of, and 1 day after, HCG administration were significantly lower in the L group than the cL group (P < 0.01 ). CONCLUSIONS: Continuation of GnRH agonist administration during the luteal phase might facilitate implantation, and prevent the profound suppression of serum gonadotrophins.     

中药单体调控自噬干预胚胎植入的研究进展

胚胎植入是生殖过程中最关键的步骤之一,植入失败的胚胎无法继续发育,是导致不孕的重要原因之一。胚胎植入的成功依赖于子宫内膜的高容受性和具有植入能力的胚胎。自噬是细胞质、细胞器和内含物被双膜囊泡吸收并运输到溶酶体进行降解和再循环的过程,是一种维持内环境稳态的方式。大量证据表明,自噬在胚胎植入的各个环节有着重要的作用。基于此探讨了自噬与子宫内膜容受性和胚胎植入能力的关系,并根据最新的研究进展,梳理了大黄素、梓醇、芍药苷、白藜芦醇、叶酸、玉米赤霉烯酮、姜黄素、汉黄芩素、槲皮素、白杨素、小檗碱、芹菜素、菲西汀、山柰酚在内的14种中药单体调控自噬干预胚胎植入的不同环节的5个机制,包括促进子宫内膜基质细胞蜕膜化、促进细胞凋亡、调节激素水平、协调炎症、促进排卵,希望对今后中药单体提高胚胎植入的成功率提供参考及思路。     

不同影像技术对胰腺癌模型兔原位种植建模效果的评价与比较

目的:比较CT、MRI及超声平扫检查对胰腺癌模型兔建模效果的评价价值。方法:建立胰腺癌模型兔10只,对每只模型兔采用CT、MRI、超声平扫等影像检查,比较不同影像技术对模型兔肿瘤病灶的检出率;并对肿瘤采用磁共振波谱(MRS)分析肿瘤代谢情况。结果:建模成功3周末,死亡5只,存活5只;3种检查方式均能发现胰腺区的肿瘤病变和腹腔积液,检出率均能够达到100%。在对肿大淋巴结和血管包绕的检出中,MRI与CT的检出率相当,均优于超声平扫;在对远处转移的检出中,MRI要优于另外两种方式,但三种影像检查方法的病灶肿大淋巴结、血管包绕及远处转移等检出率比较,差异均无统计学意义(χ²=3.619,χ²=3.000,χ²=6.857;P>0.05)。MRS分析能够清晰显示胆碱(Ch)、肌酐(Cr)和N-乙酰天门冬氨酸(NAA)峰。结论:对动物肿瘤模型采用CT、MRI和超声平扫检查,可以获得较为满意的检测效果,但是在行动物实验过程中,需要根据实际的肿瘤种植位置和肿瘤转移位置采用合适的影像检查方法。     

不同材料双J管对兔输尿管的影响

目的：观察不同材料双J管对兔输尿管的影响。方法：本实验通过三种双J管置于15例（每一种双J管5例）正常兔的输尿管内,6周后观察其对输尿管上皮的损伤,输尿管的反应变化,双J管长壳的程度,置管前后肾盂压力的变化,结果：三种双J管均产生上皮细胞的损伤,二种国产双J管所引起的输尿管反应性较小。而进口双J管较重,与之相反,国产双J管长结古石的程度远较进口双J管严重（P＜0．05）,置管6周后与管前比较肾盂压力无明显变化（P＜0．05）,结论：国产双J管有较严重的长结石的倾向,但输尿管的反应性变化较小,适合于短时间置管,进口双J管的输尿管反应性变化较重,便有较长长结石倾向,比较适合于篚置管,尽管这些为动物实验所得结果,但也可能与临床有关系。