Leukemia Inhibitory Factor mRNA Expression Research Articles

Oil-Based Hysterosalpingography ?mproves Leukaemia ?nhibitory Factor Expression ?n Endometrial Flushing Samples

Objective: The biological mechanism of the fertility-enhancing effect of hysterosalpingography (HSG) is not fully known. Leukemia inhibitory factor (LIF) is an important cytokine involved in implantation. This study was planned to investigate the effect of HSG on LIF mRNA expression in endometrial flushing samples. Methods: Forty infertile patients scheduled for HSG were included in the study. Before HSG, endometrial flushing was performed in the mid-luteal phase, followed by contrast-medium infusion into the cavity. Second flushing was done in the mid-luteal phase of the next cycle. Ten patients who underwent diagnostic hysteroscopy were taken as the second control group. LIF mRNA levels were measured by RT-PCR in endometrial flushing samples collected from each group. Results: The pre-HSG LIF mRNA levels of the infertile group were significantly lower than those of the fertile group. In infertile patients, LIF mRNA expression increased 3.2 times after HSG compared to baseline levels. LIF values reached fertile levels after HSG. While the LIF levels measured in the hysteroscopy group were significantly lower than in fertile patients, they were similar to the pre-HSG values of infertile patients. LIF levels of infertile patients after HSG were found to be significantly higher than those of the hysteroscopy group. Conclusions: In infertile patients, HSG contributes to receptivity by increasing LIF mRNA synthesis.

Decidualization of Stromal Cells Promotes Involvement of Mast Cells in Successful Human Pregnancy by Increasing Stem Cell Factor Expression.

Decidualization of endometrial stromal cells and the presence of immunocompetent cells, including human mast cells, play important roles in the establishment of pregnancy. In the present study, the effects of decidualization of endometrial stromal cells on the function of decidual mast cells were elucidated. The in vitro assay revealed that decidualization of an endometrial stromal cell line, T HESCs, increased stem cell factor (SCF) mRNA expression. Decidualization of T HESCs enhanced the production of leukemia inhibitory factor (LIF), and the migration of LAD2 cells when co-cultured with T HESCs and LAD2 cells. In addition, decidualization of T HESCs enhanced cell migration in a human trophoblast cell line, HTR-8/SVneo, increased CD9 expression, a marker for extravillous trophoblast (EVT) differentiation, and decreased the secretion of β human chorionic gonadotropin (hCG), a marker for syncytiotrophoblast (ST) differentiation, when co-cultured with T HESCs, LAD2 cells, and HTR-8/SVneo cells, in a LIF-dependent manner. Histological samples from uterine pregnancies, including decidual stromal cells, showed increased SCF mRNA expression, mast cell numbers and LIF mRNA expression thereof compared with tubal pregnancy. SCF produced by decidual stromal cells enhanced the migration and LIF production of mast cells, and promoted the migration and differentiation of trophoblasts to increase the likelihood of successful human pregnancy.

Endometrial injury concurrent with hysteroscopy increases the expression of Leukaemia inhibitory factor: a preliminary study

ObjectiveIt is not known by which mechanism endometrial injury increases pregnancy rates. Leukaemia inhibitory factor (LIF) is a cytokine involved in wound healing and implantation. The aim of this study was to determine the change in endometrial LIF mRNA expression before and after mechanical injury during hysteroscopy.MethodsForty patients with a history of two or more unsuccessful implantations who decided to undergo hysteroscopy in the proliferative phase were divided into two equal groups: one with endometrial injury (scratching group) and the other with noninjury (control group). Endometrial sampling was conducted before injury on the patients in the scratching group, and then injury was performed with monopolar needle forceps. Only diagnostic hysteroscopy was performed on the patients in the control group. Endometrial tissues were collected using a Pipelle catheter between Days 20 and 23 of the mid-luteal phase of the next cycles in both the scratching and control groups. Endometrial LIF mRNA expression was evaluated with the use of reverse-transcription polymerase chain reactions.ResultsRelative changes in mRNA expression levels of the LIF gene in endometrial samples taken before and after injury were calculated using the 2-ΔΔCt method, and the fold changes obtained were compared between and within the groups. Compared with preinjury values, an 11.1-fold increase was found in postinjury LIF mRNA expression in patients with monopolar forceps injury (p < 0.001). There was a 3.9-fold significant increase in postinjury LIF mRNA levels compared with those in the control group (p < 0.02).ConclusionsThe fertility-promoting effect of hysteroscopy-guided mechanical endometrial injury may be mediated by LIF mRNA.

Leukemia inhibitory factor is involved in the pathogenesis of NSCLC through activation of the STAT3 signaling pathway.

Leukemia inhibitory factor (LIF) is a tumor promoter in several cancer types. However, the role of LIF in non-small cell lung cancer (NSCLC) remains to be explored. The present study explored the hypothesis that LIF is important for NSCLC development by measuring LIF expression and its downstream signal transducer and activator of transcription 3 (STAT3) phosphorylation in tumor samples derived from patients with NSCLC. The association between LIF expression and clinical features was analyzed in two cancer subtypes. The effects of LIF on cell proliferation, migration and invasion were also evaluated in a NSCLC-derived cell line, A549. LIF mRNA and protein expression levels were significantly higher in tumor tissues compared with those in the corresponding adjacent and normal lung tissues. Regarding NSCLC subtypes, LIF expression was significantly higher in adenocarcinoma than in squamous cell carcinoma tissues. It was also found that phosphorylated-STAT3 levels were higher in tumor tissues compared with those in the corresponding adjacent and normal lung tissues, which was in agreement with the LIF expression levels in NSCLC tissues. Clinically, overexpression of LIF was positively correlated with aggressive tumor characteristics, including lymph node metastasis and advanced tumor stage. In A549 cells, LIF treatment enhanced cell proliferation, migration and invasion. LIF also increased STAT3 phosphorylation in A549 cells, and the STAT3 inhibitor Stattic decreased A549 cell migration and invasion following LIF stimulation. The present results demonstrate that LIF is overexpressed in NSCLC, and that LIF can promote NSCLC development through activation of the STAT3 signaling pathway. The present study indicates that LIF may serve as a potential prognostic marker for NSCLC.

ATP and repetitive electric stimulation increases leukemia inhibitory factor expression in astrocytes: A potential role for astrocytes in the action mechanism of electroconvulsive therapy.

Electroconvulsive therapy (ECT) is effective for psychiatric disorders. However, its action mechanism remains unclear. We previously reported that transcription factor 7 (TCF7) was increased in patients successfully treated with ECT. TCF7 regulates Wnt pathway, which regulates adult hippocampal neurogenesis. Adult hippocampal neurogenesis is involved in the pathophysiology of psychiatric disorders. Astrocytes play a role in adult hippocampal neurogenesis via neurogenic factors. Of astrocyte-derived neurogenic factors, leukemia inhibitory factor (LIF) and fibroblast growth factor 2 (FGF2) activate Wnt pathway. In addition, adenosine triphosphate (ATP), released from excited neurons, activates astrocytes. Therefore, we hypothesized that ECT might increase LIF and/or FGF2 in astrocytes. To test this, we investigated the effects of ATP and electric stimulation (ES) on LIF and FGF2 expressions in astrocytes. Astrocytes were derived from neonatal mouse forebrain and administered ATP and ES. The mRNA expression was estimated with quantitative reverse-transcription polymerase chain reaction. Protein concentration was measured with ELISA. ATP increased LIF, but not FGF2, expression. Multiple ES, but not single, increased LIF expression. Knockdown of P2X2 receptor (P2X2R) attenuated ATP-induced increase of LIF mRNA expression. In contrast, P2X3 and P2X4 receptors intensified it. P2X2R may mediate ATP-induced LIF expression in astrocytes and multiple ES directly increases LIF expression in astrocytes. Therefore, both ATP/P2X2R and multiple ES-induced increases of LIF expression in astrocytes might mediate the efficacy of ECT on psychiatric disorders. Elucidating detailed mechanisms of ATP/P2X2R and multiple ES-induced LIF expression is expected to result in the identification of new therapeutic targets for psychiatric disorders.

PPARβ/δ ligands regulate the expression of immune response mediators in the porcine endometrium – An in vitro study

The peroxisome proliferator-activated receptor (PPAR) β/δ belongs to a group of nuclear receptors that act as transcription factors. PPAR β/δ plays a significant role in the regulation of female reproductive processes. It has been demonstrated that PPARβ/δ is expressed in mouse, rat and porcine endometrium during the estrous cycle and pregnancy. The current study aimed to investigate the effect of selected PPARβ/δ ligands on the expression of nuclear factor kappa (NF-κB) and selected cytokines – interleukin (IL)-1β, IL-6, IL-8, IL-4, IL-10, leukemia inhibitory factor (LIF), in the porcine endometrium on days 10–12 and 14–16 of the estrous cycle (mid- and late-luteal phases corresponding to the full activity and luteolysis of the corpus luteum, respectively) and pregnancy (maternal recognition of pregnancy and beginning of implantation, respectively). Endometrial slices were incubated in vitro in the presence of PPARβ/δ agonist L-165,041 (1 or 10 μM) or antagonist GW9662 (10 μM). The expression of mRNA and protein of the immune response mediator in the tissues was determined by real-time PCR and Western Blot. In general, the PPARβ/δ agonist inhibited endometrial NF-κB mRNA expression during all analyzed reproductive stages, but it did not change protein expression. In turn, the PPARβ/δ antagonist increased NF-κB protein levels on days 10–12 of the estrous cycle or pregnancy. The presence of the PPARβ/δ agonist stimulated mRNA expression of LIF, IL-1β and IL-8 and decreased the expression of IL-6. The presence of PPARβ/δ ligands had a varied effect on protein expression in different stages on the analyzed period. The obtained results indicate that PPARβ/δ regulates the expression of endometrial NF-κB and selected cytokines in pigs. The effects of PPARβ/δ ligands on immune response mediators varied subject to the reproductive status of females and could be associated with differences in endometrial receptivity.

Vascular endothelial growth factor is up-regulated by leukemia inhibitory factor and interleukin-6 in human endometriotic stromal cells

Objective: To compare the expression of leukemia inhibitory factor (LIF), interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) in tissue and fluid samples from patients with endometriosis, and investigate whether LIF and IL-6 regulate VEGF in human endometriotic stromal cells (ESC). Methods: The levels of VEGF, LIF, IL-6 in serum, peritoneal fluid of patients with and without endometriosis were measured by ELISA. The mRNA of these three factors in the ectopic and eutopic endometrial tissue and stromal cells were measured by real-time PCR. ESC derived from ovarian endometriomas were cultured using the method of primary cell culture with LIF and IL-6, and the level of VEGF mRNA and protein were measured by the method of real-time PCR and ELISA respectively. Results: VEGF and IL-6 concentration were 1.2 and 1.3 times higher in the serum of patients with endometriosis than in the control group [(94±19) versus (78±17) ng/L; (45±14) versus (35±9) ng/L; all P<0.05]. VEGF and IL-6 concentration were 1.2 and 1.4 times higher in the peritoneal fluid of patients with endometriosis than in the control group [(110±25) versus (91±21) ng/L; (69±20) versus (49±15) ng/L; all P<0.05]. VEGF and IL-6 concentrations in peritoneal fluid of patients with endometriosis were 1.2 and 1.5 times higher than in serum (all P<0.01). VEGF, LIF and IL-6 mRNA expression were 2.2, 8.6, 44.7 times higher in ESC compared with the matching eutopic endometrial stromal cells (all P<0.01). LIF and IL-6 mRNA were 2.0 and 64.8 times higher in ectopic endometrial tissue than the matching eutopic endometrial tissue (all P<0.05).ESC cultured with LIF, IL-6 and LIF+IL-6 induce VEGF protein secretion [(106±18), (124±30), (140±27) ng/L] by 1.3, 1.5 and 1.7 times (all P<0.05). Conclusion: Overexpression of LIF and IL-6 may synergistically contribute to upregulation of VEGF in ESC and promote development of endometriosis.

Evaluation of Laparoscopic Intervention versus Ultrasound Guided Aspiration of Bilateral Hydrosalpinges on Endometrial LIF mRNA Expression Level and Pregnancy Outcome after IVF-ET Cycle

Background : Hydrosalpinx is a common gynecological dis­ease. 30% of infertile women undergoing in vitro fertilization-embryo transfer (IVF-ET) have hydrosalpin­x. Leukemia inhibitory factor (LIF) mRNA expression level is lower in the endometrium during the implantation window in the presence of bilateral hydrosalpinges. If the hydrosalpinx is removed, LIF mRNA expression returns to normal values. Objectives: This study was designed to evaluate laparoscopic intervention of bilateral hydrosalpinges versus transvaginal ultrasound guided aspiration on LIF mRNA expression level during implantation window and pregnancy outcome after IVF-ET cycle. Methodology : Sixty patients who had bilateral hydrosalpinges were classified into two groups; 30 women underwent laparoscopic salpingectomy or proximal tubal occlusion and 30 women underwent transvaginal ultrasound guided aspiration. Determination of LIF mRNA expression level in endometrial samples was performed preoperatively and in the 3 rd postoperative cycle. In addition, pregnancy outcome was evaluated in the first IVF-ET cycle. Results: Endometrial LIF mRNA expression level in laparoscopic group significantly increased postoperatively than transvaginal ultrasound guided aspiration group with a significant difference (P=0.03). In addition, there is increased levels in patients undergoing laparoscopic and ultrasound guided aspiration groups after treatment than before with a significant difference (P=0.005) and (P =0.04); respectively. As regards pregnancy outcome, it is more favorable in laparoscopic group than ultrasound guided aspiration with statistically significant difference (P=0.013). Conclusion: Our findings showed that endometrial LIF mRNA expression level was increased and pregnancy outcome was more favorable after laparoscopic inter­vention versus transvaginal ultrasound guided aspiration for treatment of bilateral hydrosalpinges patients. , Egypt

Interferon-γ differentially modulates the impact of tumor necrosis factor-α on human endometrial stromal cells

The pro-inflammatory T helper (Th)-1 cytokines, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), are immunological factors relevant at the feto-maternal interface and involved in the pathophysiology of implantation disorders. The synergistic action of the two cytokines has been described with regard to apoptotic cell death and inflammatory responses in different cell types, but little is known regarding the human endometrium. Therefore, we examined the interaction of TNF-α and IFN-γ in human endometrial stromal cells (ESCs). ESCs were isolated from specimens obtained during hysterectomy and decidualized in vitro. Cells were incubated with TNF-α, IFN-γ or signaling-inhibitor. Insulin-like growth factor binding protein (IGFBP)-1, prolactin (PRL), leukemia inhibitory factor (LIF), interleukin (IL)-6, IL-8, regulated on activation normal T-cell expressed and secreted protein (RANTES) and monocyte chemotactic protein (MCP)-1 were measured using ELISA and real-time RT-PCR. Nuclear factor of transcription (NF)-κB and its inhibitor (IκBα) were analyzed by in-cell western assay and transcription factor assay. TNF-α inhibited and IFN-γ did not affect the decidualization of ESCs. In contrast, IFN-gamma differentially modulated the stimulating effect of TNF-alpha on cytokines by enhancing IL-6, RANTES and MCP-1 and attenuating LIF mRNA expression. These effects were time- and dose-dependent. IFN-γ had no impact on the initial activation of NF-κB signaling. Histone-deacetylase activity was involved in the modulating effect of IFN-γ on RANTES secretion. These observations showed a distinct pattern of interaction of the Th-1 cytokines, TNF-α and IFN-γ in the human endometrium, which could play an important role in the pathophysiology of implantation disorders.

Expression of leukaemia inhibitory factor at the conceptus?maternal interface during preimplantation development and in the endometrium during the oestrous cycle in the mare.

Leukaemia inhibitory factor (LIF) plays a critical role in blastocyst development and implantation in several species. The present study investigated mRNA and protein expression for LIF, as well as the low-affinity LIF receptor (LIFR) and interleukin-6 signal transducer (IL6ST), in equine endometrium, trophoblast and histotroph during early pregnancy and in the endometrium during the oestrous cycle. Endometrial LIF mRNA expression was upregulated after Day 21 of pregnancy, whereas LIF immunoreactivity increased in the endometrium on Day 28. Expression of LIF mRNA in the yolk sac membrane increased from Day 21 of pregnancy, whereas LIF immunoreactivity increased from Day 28 in the trophoblast. LIFR and IL6ST mRNA was expressed in the endometrium during both the oestrous cycle and early pregnancy and, although LIFR and IL6ST protein were localised to the glandular epithelium during the cycle and first 14 days of pregnancy, from Day 21 they were located in the luminal epithelium. Trophoblast expression of LIFR and IL6ST increased as pregnancy proceeded. In conclusion, LIF expression increased at the conceptus-maternal interface during capsule attenuation. Because contemporaneous upregulation of both LIFR and IL6ST was also observed in the trophoblast, we propose that LIF plays an important role in the development of endometrial receptivity for trophoblast growth, apposition and adhesion in mares.

HIF-2α mediates hypoxia-induced LIF expression in human colorectal cancer cells.

Leukemia inhibitory factor (LIF), a multi-functional cytokine, has a complex role in cancer. While LIF induces the differentiation of several myeloid leukemia cells and inhibits their growth, it also promotes tumor progression, metastasis and chemoresistance in many solid tumors. LIF is frequently overexpressed in a variety of human tumors and its overexpression is often associated with poor prognosis of patients. Currently, the mechanism for LIF overexpression in tumor cells is not well-understood. Here, we report that hypoxia, a hallmark of solid tumors, induced LIF mRNA expression in human colorectal cancer cells. Analysis of LIF promoter revealed several hypoxia-responsive elements (HREs) that can specifically interact with and be transactivated by HIF-2α but not HIF-1α. Consistently, ectopic expression of HIF-2α but not HIF-1α transcriptionally induced LIF expression levels in cells. Knockdown of endogenous HIF-2α but not HIF-1α by siRNA largely abolished the induction of LIF by hypoxia in cells. Furthermore, there is a strong association of HIF-2α overexpression with LIF overexpression in human colorectal cancer specimens. In summary, results from this study demonstrate that hypoxia induces LIF expression in human cancer cells mainly through HIF-2α, which could be an important underlying mechanism for LIF overexpression in human cancers.

Bu Shen Huo Xue decoction restores endometrial leukemia-inhibitory factor but not Angiopoietin-2 expression, and improves uterine receptivity in the controlled ovarian stimulation rat model.

Leukemia-inhibitory factor (LIF) and Angiopoietin-2 (Ang-2) are important factors in fertility. In the present study, it was investigated whether Bu Shen Huo Xue Decoction (BSHXD) prevents controlled ovarian hyperstimulation (COH) treatment-induced changes in endometrial LIF and Ang-2 expression and whether it has an effect on the number of implantation sites and live births in rats. Uteri were collected on day (D) 3, 4 and 5 of pregnancy, and LIF and Ang-2 protein and mRNA expression were detected using western blot analysis and quantitative polymerase chain reaction. On pregnancy D10, the average number of implantation sites was observed. The number of live births from each group was recorded. The results indicated that BSHXD treatment markedly increased the number of live births by restoring endometrial LIF expression and the implantation capacity in the COH rat model. In addition, no association was identified between LIF and Ang-2 expression. Therefore, this suggests that BSHXD may be useful for female reproduction.

109 EXPRESSION OF GENES RELATED TO ENDOMETRIAL RECEPTIVITY IN EQUINE ENDOMETRIUM DURING THE ESTROUS CYCLE AND EARLY PREGNANCY

A set of genes that display differential expression levels in the reproductive tract could serve as beneficial markers of endometrial receptivity. SERPINA14 is present in the uterus during pregnancy and suppresses lymphocyte accumulation. Osteopontin is the ligand of integrin β3 and enables trophoblast communication during implantation. Leukemia inhibitory factor (LIF) is involved in inflammatory cell signalling and contributes to implantation by regulating immune cells. The objective was to assess the expression of SERPINA14, osteopontin, and LIF mRNAs in the equine endometrium during the oestrous cycle and early pregnancy. Biopsies were obtained from mares on day of ovulation (d 0, n = 4), late diestrus (LD, n = 4, high progesterone [P4]), and after luteolysis at the beginning of oestrus phase (AL, n = 4, &lt;1 ng mL–1 P4) of the cycle. Biopsies were also taken on days 14 (P14, n = 4), 18 (P18, n = 4), and 22 (P22; n = 4) of pregnancy. Relative mRNA expression levels of genes were quantified using real-time quantitative RT-qPCR in duplicate. Data were analysed using one-way ANOVA, and l.s.d. test was applied. Both the oestrous cycle and early pregnancy increased SERPINA14 mRNA levels compared to d0. Expression of LIF mRNA was not significantly regulated except for a decline at AL. Expression of osteopontin mRNA was up-regulated during the oestrous cycle at LD while early pregnancy inhibited this up-regulation. The results suggest that the genes studied related to endometrial receptivity are strictly regulated accordingly to the stage of oestrous cycle, probably by circulating ovarian steroids, specifically progesterone, and pregnancy-associated factors are also involved in this regulation. This project was partially funded by TUBITAK 107O035 to AG and DUBAP 14VF12 to MOA. MH was supported by OYP 2013-090.

Prokineticin 1 and leukemia inhibitory factor mRNA expression in the endometrium of women with idiopathic recurrent pregnancy loss

To determine the expression patterns of prokineticin 1 (PROK1) and leukemia inhibitory factor (LIF) mRNA differ in peri-implantation endometrial tissue of women with idiopathic recurrent pregnancy loss (RPL) from normal fertile women. A case-control study. University-based tertiary care center. 30 women with idiopathic RPL and 30 fertile controls. Endometrial biopsies. Real-time polymerase chain reaction analysis for expression of PROK1 and LIF mRNA. The expression of PROK1 and LIF was statistically significantly increased in the endometrium of the women with idiopathic RPL compared with the controls. Furthermore, increased LIF expression was observed in the endometrium of women with idiopathic RPL compared with controls. An increased mRNA expression of PROK1 and LIF could be one of the several abnormalities characterizing the endometrium in women with RPL.

Tissue levels of leukemia inhibitory factor vary by osteoarthritis grade.

The objective of this study was to observe the expression of leukemia inhibitory factor (LIF) in animals and in different clinical grades of patient osteoarthritic tissues. Thirty-five rabbits were used in a Colombo model of experimental osteoarthritis (OA). Five rabbits each were sacrificed on postoperative days 3, 7, 14, 28, 42, 56, and 84. Immunohistochemistry analysis for LIF expression and distribution in the cartilage and synovium of animals was performed at these times. Sixty-seven samples of human articular tissue were obtained from patients with different grades of OA according to symptoms and radiographic inspection. The mRNA expression of LIF was determined by reverse transcription polymerase chain reaction, and LIF protein was determined by enzyme-linked immunosorbent assay (ELISA). The results showed a slight expression of LIF in normal cartilage tissue but less in synovium tissue; however, the expression of LIF was marked in synovial lining cells and superficial and middle-layer cartilage in animal OA (P<.05). Leukemia inhibitory factor mRNA was expressed at the highest level in moderate degrading subchondral bone, and LIF was expressed at the highest level in seriously degrading articular cartilage tissue. These results were similar to those found with ELISA. This study suggests that LIF in OA articular tissues varies by clinical symptoms and grade. It plays an important role in the pathogenesis of OA.

Effect of Uterine Flushing Leukemia Inhibitory Factor on Reproductive Outcome of Infertile Couple

Aim: To determine the role of Leukemia Inhibitory Factor (LIF) in predicting the reproductive outcome in infertile couple. Method of study: Uterine flushing and endometrialsamples were collected from infertile women during implantation window with stage I/II endometriosis (n=17), patients with idiopathic infertility (n=24), luteal phase defect (n=16), and fertile control (n=26). LIF was assessed in uterine flushings in all patients by ELISA. In endometrium, semiquantitative RT-PCR was performed for LIF mRNA expression. Reproductive outcome of all infertile women were recorderd. Results: 34.6% of patients included in the study got pregnant. LIF concentration had 96.5% sensitivity and 86.1% specificity at a cut-off point of 2.45 pg/ml for predicting the reproductive outcome. Conclusion: LIF in uterine flushing could be used as a predictor of successful reproductive outcome in infertile women.

Progesterone Is Essential for Protecting against LPS-Induced Pregnancy Loss. LIF as a Potential Mediator of the Anti-inflammatory Effect of Progesterone

Lipopolysaccharide (LPS) administration to mice on day 7 of gestation led to 100% embryonic resorption after 24 h. In this model, nitric oxide is fundamental for the resorption process. Progesterone may be responsible, at least in part, for a Th2 switch in the feto-maternal interface, inducing active immune tolerance against fetal antigens. Th2 cells promote the development of T cells, producing leukemia inhibitory factor (LIF), which seems to be important due to its immunomodulatory action during early pregnancy. Our aim was to evaluate the involvement of progesterone in the mechanism of LPS-induced embryonic resorption, and whether LIF can mediate hormonal action. Using in vivo and in vitro models, we provide evidence that circulating progesterone is an important component of the process by which infection causes embryonic resorption in mice. Also, LIF seems to be a mediator of the progesterone effect under inflammatory conditions. We found that serum progesterone fell to very low levels after 24 h of LPS exposure. Moreover, progesterone supplementation prevented embryonic resorption and LPS-induced increase of uterine nitric oxide levels in vivo. Results show that LPS diminished the expression of the nuclear progesterone receptor in the uterus after 6 and 12 h of treatment. We investigated the expression of LIF in uterine tissue from pregnant mice and found that progesterone up-regulates LIF mRNA expression in vitro. We observed that LIF was able to modulate the levels of nitric oxide induced by LPS in vitro, suggesting that it could be a potential mediator of the inflammatory action of progesterone. Our observations support the view that progesterone plays a critical role in a successful pregnancy as an anti-inflammatory agent, and that it could have possible therapeutic applications in the prevention of early reproductive failure associated with inflammatory disorders.

Regulation of expression and role of leukemia inhibitory factor and interleukin-6 in the uterus of early pregnant pigs

Cytokines, which are generally involved in the process of inflammation, may also play a critical role in conceptus implantation. We examined: (1) the expression profiles of leukemia inhibitory factor (LIF) and interleukin (IL)-6 mRNA and their protein content in the endometrium of cyclic and pregnant gilts on Days 10 to 18 after estrus; (2) the effect of conceptus-exposed medium on LIF and IL-6 synthesis in the endometrium; (3) the profiles of IL6R and LIFR mRNA expression in pig conceptuses collected on Days 10 to 18 of pregnancy; and (4) the effect of LIF and IL-6 on the attachment and proliferation of porcine trophoblast cells. The expression of LIF mRNA in the endometrium increased between Days 10 and 12 in both cyclic and pregnant gilts, and tended to be higher in Day 12 pregnant animals compared with nonpregnant ones. The LIF protein content in the uterine lumen peaked on Day 12 of pregnancy, and was higher than on Day 12 of the estrous cycle. Endometrial IL-6 mRNA expression was upregulated on Day 12 in pregnant gilts compared with nonpregnant animals. Moreover, a higher content of IL-6 protein was observed in pregnant than in cyclic gilts. The addition of conceptus-exposed medium resulted in up-regulation of LIF and IL6 mRNA expression, and increased IL-6 content in endometrial slices. In conceptuses, increased mRNA expression was detected on Days 10 to 14 for IL6R and on Day 14 for LIFR, when compared with other days studied. LIF and IL-6 stimulated the attachment and proliferation of trophoblast cells in vitro. In summary, LIF and IL-6 are important components of embryo-uterine interactions during early pregnancy in the pig, and may contribute to successful conceptus implantation.

Assessment of leukemia inhibitory factor and glycoprotein 130 expression in endometrium and uterine flushing: a possible diagnostic tool for impaired fertility

BackgroundUterine receptivity and implantation are complex processes requiring coordinated expression of molecules by zygote and uterus. Our objective was to evaluate the role of the endometrial expression of leukemia inhibitory factor (LIF) and its glycoprotein 130 (gp130) receptor molecules and their secretion in uterine flushing during the window of implantation in cases of primary unexplained infertilityCase presentationThe study was conducted on 25 infertile women with unexplained infertility for at least two years and 10 normal fertile women as a control group . Endometrial tissue and uterine flushing were obtained. Each tissue specimen was divided into two pieces; one piece was used for histological dating of the endometrium and for immunostaining of progesterone receptors, and the second was used for RNA extraction and PCR assay of LIF and gp130 mRNA expression. Serum estrogen and progesterone were measured for all subjects. LIF mRNA was expressed in the endometrium of all normal fertile women but significantly decreased in infertile women. LIF was not detectable in 88% of infertile women while it was fairly detectable in 12% of them. Gp130 mRNA was hardly detectable in both fertile and infertile women with no difference between them. Infertile women secreted significantly less LIF and gp130 molecules in the uterine flushing compared with normal fertile women.ConclusionsExpression of LIF mRNA in endometrium could be used as a molecular marker of unexplained infertility. Assessment of secreted LIF and gp130 molecules in uterine flushing could be another useful and safe method for predicting successful implantation as well as for diagnosing and eventually treating women with impaired fertility using recombinant human LIF.

Semi-quantitative analysis of endometrial receptivity marker mRNA expression in the mid-secretory endometrium of patients with uterine fibromas

In fertile women, expression of molecular marker of endometrial receptivity, HOXA11, leukemia inhibitory factor (LIF) and basic transcriptional element binding protein 1 (BTEB1), rises during the luteal phase with the peak occurring during the implantation window. We evaluated the transcript levels of HOXA-11, LIF and BTEB1 in the mid-secretory endometrium of infertile patients with uterine fibroid infertility (n = 8) and from normal fertile women (n = 8). Expression levels of HOXA11, LIF and BTEB1 mRNA were measured in endometrium during the mid-secretory phase using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Endometrial HOXA11, LIF and BTEB1 mRNA expression levels (normalized to s-actin expression) were significantly decreased in endometrium of infertile patients with uterine fibroid as compared with healthy fertile controls at the time of implantation (P<0.05). The results suggest that the alteration in expression pattern of some genes could account for some aspects of infertility in patients with uterine fibroma. Key words: Myoma, fibromas, implantation, HOXA11, leukemia inhibitory factor, basic transcriptional element binding protein 1.