Mood disorders influencing endometriosis and adenomyosis: Mendelian randomisation study.

BACKGROUND: Many studies have found an association between mood-disorder-related traits and endometriosis and adenomyosis. However, the cause-effect relationship remains unclear. AIMS: We conducted Mendelian randomisation analyses to evaluate any causal relationship between mood disorders and endometriosis as well as different sites of endometriosis. METHOD: Summary-level statistics for mood-disorder-related traits and endometriosis (8288 cases, 68 969 controls) in European populations were derived from large-scale data-sets of genome-wide association studies. A two-sample Mendelian randomisation was performed using the inverse-variance weighted and weight median methods. Further sensitivity analyses, including heterogeneity, pleiotropy and leave-one-out analyses, were conducted to test the consistency of the results. RESULTS: Genetically determined mood swings (odds ratio = 2.557, 95% CI: 1.192-5.483, P = 0.016) and major depression (odds ratio = 1.233, 95% CI: 1.019-1.493, P = 0.031) were causally associated with an increased risk of endometriosis. Mood swings (odds ratio = 4.238, 95% CI: 1.194-15.048, P = 0.025) and major depression (odds ratio = 1.512, 95% CI: 1.052-2.173, P = 0.025) were also causally associated with the risk of adenomyosis. Sensitivity analyses confirmed the reliability of the results. CONCLUSIONS: Our results suggest that mood-disorder-related traits increase the risk of endometriosis and adenomyosis. This study provides new insights into the potential pathogenesis of endometriosis and adenomyosis, and highlights the importance of preventing endometriosis and adenomyosis in patients with mood-disorder-related traits.

Number of embryos transferred could possibly be associated with angular pregnancy in in vitro fertilization-embryo transfer.

OBJECTIVE: The probability of embryo implantation in an abnormal location is significantly higher in assisted reproductive technology (ART) than in natural pregnancies. Angular pregnancy is an eccentric intrauterine pregnancy with embryo implantation in the lateral superior angle of the uterine cavity. Cycle-level factors associated with angular pregnancy in patients conceived with ART needed to be explored. METHODS: A total of 11 336 clinical pregnancies cycles were included. Angular pregnancy rate was compared among groups according to the type of embryos transferred. Among them, 53 cases of angular pregnancy and 159 cases of normal intrauterine pregnancy were screened out using propensity score matching. Risk factors of angular pregnancy were explored. RESULTS: The angular pregnancy rate was 0.31% (14/4572) in the day 5 blastocyst transfer group, 0.58% (39/6764) in non-day 5 embryo transfer group, with 0.55% (29/5280) in day 3 embryo transfer and 0.67% (10/1484) in the day 6 blastocyst group, respectively. A multifactor regression analysis was performed and indicated that the number of embryos transferred was significantly associated with angular pregnancy (P = 0.031, OR, 2.23, 95% CI: 1.09-4.68). CONCLUSION: Multiple embryo transfer could possibly be associated with an increased incidence of angular pregnancy in patients conceived with ART.

Chronic endometritis positively correlates with the aggravation of intrauterine adhesions but has limited effects on reproductive prognosis with antibiotic application.

OBJECTIVE: To assess the effect of chronic endometritis (CE) diagnosed by CD138 staining on the aggravation of intrauterine adhesions (IUAs), and the reproductive prognosis after transcervical resection of adhesions (TCRA). METHODS: Sixty-three patients with severe IUAs (group A) and 119 patients with moderate IUAs (group B) were included in this retrospective study. TCRA and endometrial biopsy with CD138 staining were performed. Participants in each group were classified into two subgroups: CE group and NCE group (without CE). Patients were treated with a course of oral antibiotics for 2 weeks after TCRA. Embryo transfer would be performed if patients had embryos after operations. RESULTS: Increased incidence of CE was found in group A (18/63, 28.57%) compared with group B (18/119, 15.13%) (P = 0.030). No significant differences were found in the comparisons of chemical pregnancy rate, early miscarriage rate, or full-term pregnancy rate between the CE group and NCE group (P > 0.05), in either the subgroup analysis of group A and group B, or the total analysis. CONCLUSION: CE has a positive correlation with the aggravation of IUAs. CE did not have a negative impact on the reproductive prognosis of patients with moderate or severe IUAs after TCRA followed by antibiotic administration.

Interaction between Cervical Microbiota and Host Gene Regulation in Caesarean Section Scar Diverticulum.

Cesarean section scar diverticulum (CSD) has become a formidable obstacle preventing women receiving CS from reproducing. However, the pathogenesis of CSD remains unexplored. In this study, we characterized the cervical microbiota, metabolome, and endometrial transcriptome of women with CSD. Based on the 16s rRNA results of cervical microbes, the microbial diversity in the CSD group was higher than that in the control group. Lactobacillus were significantly decreased in the CSD group and were mutually exclusive with potentially harmful species (Sphingomonas, Sediminbacterium, and Ralstonia) abnormally elevated in CSD. The microbiota in the CSD group exhibited low activity in carbohydrate metabolism and high activity in fatty acid metabolism, as confirmed by the metabolomic data. The metabolomic characterization identified 6,130 metabolites, of which 34 were significantly different between the two groups. In the CSD group, N-(3-hydroxy-eicosanoid)-homoserine lactone and Ternatin were significantly increased, in addition to the marked decrease in fatty acids due to high consumption. N-(3-hydroxy-eicosanoyl)-homoserine lactone is a regulator that promotes abnormal apoptosis in a variety of cells, including epithelial cells and vascular endothelial cells. This abnormal apoptosis of endometrial epithelial cells and neovascularization was also reflected in the transcriptome of the endometrium surrounding the CSD. In the endometrial transcriptome data, the upregulated genes in the CSD group were active in negatively regulating the proliferation of blood vessel endothelial cells, endothelial cells, and epithelial cells. This alteration in the host's endometrium is most likely influenced by the abnormal microbiota, which appears to be confirmed in the results by integrating host transcriptome and microbiome data. For the first time, this study described the abnormal activity characteristics of microbiota and the mechanism of host-microbiota interaction in CSD. IMPORTANCE Cesarean section scar diverticulum (CSD) has become a formidable obstacle preventing women receiving CS from reproducing. In this study, we revealed that potentially harmful microbes do have adverse effects on the host endometrium. The mechanism of these adverse effects includes the inhibition of the activity of beneficial bacteria such as lactobacilli, consumption of protective metabolites of the endometrium, and also the production of harmful metabolites. In the present study, we elucidated the mechanism from the perspectives of microbial, metabolic, and host responses, providing an important rationale to design preventive and therapeutic strategies for CSD.

Endometrial polyp is associated with a higher prevalence of chronic endometritis in infertile women.

OBJECTIVE: To assess the prevalence of chronic endometritis (CE) among infertile women with endometrial polyps (EP). METHODS: From June 2017 to October 2021, 583 patients in the polyp group (group A-group A1: single-polyp group, 322 patients; group A2: multiple-polyp group, 261 patients) and 4534 patients in the non-polyp group (group B) were included in this retrospective study. Hysteroscopic polypectomy was performed in group A. Endometrial biopsy and CD138 immunohistochemistry staining for specimens was carried out in all groups. RESULTS: Prevalence of CE was significantly higher in group A than in group B (45.28% vs. 27.94%, P < 0.001). A significantly higher prevalence of CE was found in group A1 and group A2 compared with group B (42.24% vs. 27.94%, P < 0.001; 49.04% vs. 27.94%, P < 0.001; respectively). No significant difference in the comparison of CE prevalence was found between group A1 and group A2. Similar results were achieved in the subgroup analysis among patients aged 40 years or older and patients younger than 40 years. CONCLUSION: EP, either single EP or multiple EP, positively correlates with CE. The prevalence of CE was similar between the single-polyp group and the multiple-polyp group.

Correlation between hysteroscopy findings in patients with hydrosalpinx and chronic endometritis.

OBJECTIVE: To evaluate the role of hydrosalpinx in susceptibility to chronic endometritis (CE). METHODS: This is a retrospective cohort study, which includes 624 patients with hydrosalpinx (group A) and 789 patients without hydrosalpinx (group B) undergoing laparoscopy and hysteroscopy simultaneously. Endometrial morphology was recorded under hysteroscopy. Endometrial biopsy was obtained after hysteroscopy, and immunohistochemical staining for syndecan-1 (CD138) was carried out. RESULTS: No significantly statistical differences were found between the two groups when comparing the incidence of endometrial hyperemia or endometrial micro-polyps under hysteroscopy (P > 0.05). Hydrosalpinx had a significant impact on the incidence of CE (P < 0.05) (plasma cell count: no plasma cells: odds ratio [OR] 0.71, 95% confidence interval [CI] 0.58-0.88, P = 0.002; ≥1/high-power field [HPF]: OR 1.40, 95% CI 1.14-1.74, P = 0.002; ≥3/HPF: OR 1.50, 95% CI 1.18-1.91, P = 0.001; ≥5/HPF: OR 1.62, 95% CI 1.27-2.21, P < 0.001). There were no significant differences in the comparison of plasma cell count between the unilateral hydrosalpinx group (274 patients) and the bilateral hydrosalpinx group (350 patients) (P > 0.05). CONCLUSION: The presence of hydrosalpinx increased the incidence of CE. Bilateral hydrosalpinx did not significantly increase the incidence of CE compared with unilateral hydrosalpinx.

Clinical outcomes after single-versus double-embryo transfers in women with adenomyosis: a retrospective study.

BACKGROUND: Adenomyosis affects the outcomes of spontaneous fertility and assisted reproductive technology. The single blastocyst embryo transfer (SBT) policy is an effective strategy known to minimize the risk of multiple pregnancy for non-adenomyosis women. However, little is known about its applicability to women with adenomyosis. The purpose of this study is to compare pregnancy outcomes between SBT, double-blastocyst embryo transfer (DBT), single-cleavage-stage embryo transfer (SET) and double-cleavage-stage embryo transfer (DET) in the frozen-thawed embryo transfer cycles among adenomyosis patients. METHODS: This retrospective study was conducted in all frozen-thawed autologous embryo transfer cycles. 393 frozen-thawed embryo transfer cycles performed in adenomyosis patients were enrolled. The major clinical outcomes were implantation rate (IR), clinical pregnancy rate (CPR), miscarriage rate (MR), multiple pregnancy rate (MPR) and live birth rate (LBR). RESULTS: The SBT and DBT groups achieved higher IR (P < 0.001), CPR (P = 0.017), LBR (P = 0.040) and lower MR (P = 0.020) than the SET and DET groups. But the SBT and DBT groups achieved similar CPR and LBR. The SBT and SET groups achieved lower MPR (P < 0.001) than the DBT and DET groups. The average birth weight (BW) of SBT groups was higher than the DBT and DET groups (P = 0.016). When compared with SBT group, low-birth-weight infants were significantly higher with DBT and DET. CONCLUSIONS: When performing frozen-thawed embryo transfer cycles among adenomyosis patients, the SBT group has similar IR, CPR, MR, LBR but lower MPR compared to the DBT group. Therefore, SBT might be offered as standard practice.

Identification of Crucial lncRNAs, miRNAs, mRNAs, and Potential Therapeutic Compounds for Polycystic Ovary Syndrome by Bioinformatics Analysis.

BACKGROUND: This study was aimed at mining crucial long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) for the development of polycystic ovary syndrome (PCOS) based on the coexpression and the competitive endogenous RNA (ceRNA) theories and investigating the underlying therapeutic drugs that may function by reversing the expression of lncRNAs, miRNAs, and mRNAs. METHODS: RNA (GSE106724, GSE114419, GSE137684, and GSE138518) or miRNA (GSE84376 and GSE138572) expression profile datasets of PCOS patients were downloaded from the Gene Expression Omnibus database. The weighted gene coexpression network analysis (WGCNA) using four RNA datasets was conducted to construct the lncRNA-mRNA coexpression networks, while the common differentially expressed miRNAs in two miRNA datasets and module RNAs were used to establish the ceRNA network. A protein-protein interaction (PPI) network was created to explore the potential interactions between genes. Gene Ontology and KEGG pathway enrichment analyses were performed to explore the functions of genes in networks. Connectivity Map (CMap) and Comparative Toxicogenomics Database (CTD) analyses were performed to identify potential therapeutic agents for PCOS. RESULTS: Three modules (black, magenta, and yellow) were identified to be PCOS-related after WGCNA analysis, in which KLF3-AS1-PLCG2, MAPKAPK5-AS1-MAP3K14, and WWC2-AS2-TXNIP were important coexpression relationship pairs. WWC2-AS2-hsa-miR-382-PLCG2 was a crucial ceRNA loop in the ceRNA network. The PPI network showed that MAP3K14 and TXNIP could interact with hub genes PLK1 (degree = 21) and TLR1 (degree = 18), respectively. These genes were enriched into mitosis (PLK1), immune response (PLCG2 and TLR1), and cell cycle (TXNIP and PLK1) biological processes. Ten small molecule drugs (especially quercetin) were considered to be therapeutical for PCOS. CONCLUSION: Our study may provide a novel insight into the mechanisms and therapy for PCOS.

Transferrin and antioxidants partly prevented mouse oocyte oxidative damage induced by exposure of cumulus-oocyte complexes to endometrioma fluid.

BACKGROUND: Exposure of oocytes to the endometrioma fluid has an adverse effect on embryonic quality. To determine whether adding transferrin and antioxidants to culture medium could counteract detrimental effects on mouse cumulus-oocyte complexes (COCs) induced by exposure to endometrioma fluid or not, we conducted an in vitro cross-sectional study using human and mouse COCs. METHODS: Eighteen women who had their oocytes exposed to endometrioma fluid during oocyte retrieval were enrolled. COCs from superovulated ICR female mice were collected. They were first exposed to human endometrioma fluid and then treated by transferrin and/or antioxidants (cysteamine + cystine). Subsequently, COCs function was assessed by molecular methods. RESULTS: This study observed that human COCs inadvertently exposed to endometrioma fluid in the in vitro fertilization (IVF) group led to a lower good quality embryo rate compared to intracytoplasmic sperm injection (ICSI) group. Exposure of mouse COCs to endometrioma fluid accelerated oocyte oxidative damage, evidenced by significantly reduced CCs viability, defective mitochondrial function, decreased GSH content and increased ROS level, associated with the significantly higher pro-portion of abnormal spindles and lower blastocyst formation (p < 0.05, respectively). This damage could be recovered partly by treating COCs with transferrin and antioxidants (cysteamine + cystine). CONCLUSIONS: Transferrin and antioxidants could reduce the oxidative damage caused by COCs exposure to endometrioma fluid. This finding provides a promising new possibility for intervention in the human oocyte oxidative damage process induced by endometrioma fluid during oocyte pick-up.

The Effect of Sex Differences on Endothelial Function and Circulating Endothelial Progenitor Cells in Hypertriglyceridemia.

BACKGROUND: Men have a higher risk and earlier onset of cardiovascular diseases compared with premenopausal women. Hypertriglyceridemia is an independent risk factor for the occurrence of ischemic heart disease. Endothelial dysfunction is related to the development of ischemic heart disease. Whether sex differences will affect the circulating endothelial progenitor cells (EPCs) and endothelial function in hypertriglyceridemia patients or not is not clear. METHODS: Forty premenopausal women and forty age- and body mass index (BMI)-matched men without cardiovascular and metabolic disease were recruited and then divided into four groups: normotriglyceridemic women (women with serum triglycerides level <150 mg/dl), hypertriglyceridemic women (women with serum triglycerides level ≥150 mg/dl), normotriglyceridemic men (men with serum triglycerides level <150 mg/dl), and hypertriglyceridemic men (men with serum triglycerides level ≥150 mg/dl). Peripheral blood was obtained and evaluated. Flow-mediated dilatation (FMD), the number and activity of circulating EPCs, and the levels of nitric oxide (NO), vascular endothelial growth factor (VEGF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) in plasma and culture medium were measured. RESULTS: The number and activity of circulating EPCs, as well as the level of NO in plasma or culture medium, were remarkably increased in premenopausal females compared with those in males both in the hypertriglyceridemic group and the normotriglyceridemic group. The EPC counts and activity, as well as the production of NO, were restored in hypertriglyceridemic premenopausal women compared with those in normal women. However, in hypertriglyceridemic men, the EPC counts and activity, as well as levels of NO, were significantly reduced. The values of VEGF and GM-CSF were without statistical change. CONCLUSIONS: The present study firstly demonstrated that there were sex differences in the number and activity of circulating EPCs in hyperglyceridemia patients. Hypertriglyceridemic premenopausal women displayed restored endothelial functions, with elevated NO production, probably mediated by estradiol. We provided a new insight to explore the clinical biomarkers and therapeutic strategies for hypertriglyceridemia-related vascular damage.

Overexpression of long non-coding RNA nuclear enriched abundant transcript 1 inhibits the expression of p53 and improves premature ovarian failure.

It has been previously reported that the long non-coding RNA nuclear enriched abundant transcript 1 (NEAT1) can regulate cell apoptosis. The present study aimed to investigate the involvement of NEAT1 in premature ovarian failure (POF). A total of 60 patients with POF admitted at the Sixth Affiliated Hospital of Sun Yat-sen University between December 2016 and December 2018 were enrolled in the present study. Reverse transcription-quantitative PCR (RT-qPCR) was performed to measure NEAT1 expression level in tissue samples from patients with POF and healthy controls. Transient transfections were performed on two normal Chinese hamster ovary cell lines Lec8 and CHO, followed by RT-qPCR and western blot to evaluate gene interaction. Flow cytometry was performed to assess cell apoptosis. The results from the present study demonstrated that NEAT1 expression in ovarian tissues was significantly downregulated in patients with POF compared with healthy controls. Furthermore, the expression of p53 was upregulated in ovarian tissues from patients with POF compared with healthy controls and was inversely associated with NEAT1 expression. In hamster ovary cells, overexpression of NEAT1 led to inhibition of p53, whereas NEAT1 knockdown promoted the expression of p53. In addition, ovary cell apoptosis was inhibited following NEAT1 overexpression and stimulated following p53 overexpression. In conclusion, overexpression of NEAT1 may inhibit the expression of p53 and improve premature ovarian failure.

A 14-Methylation-Driven Differentially Expressed RNA as a Signature for Overall Survival Prediction in Patients with Uterine Corpus Endometrial Carcinoma.

DNA methylation has been implicated as an important mechanism for the development of uterine corpus endometrial carcinoma (UCEC), indicating that methylation-driven genes may be potential biomarkers for survival prediction. In this study, we aimed to identify a new prognostic methylation signature for UCEC based on differentially expressed genes (DEGs) and long noncoding RNAs (lncRNAs) (DELs). Sample-matched RNA-sequencing and methylation-array data were downloaded from The Cancer Genome Atlas database, by analysis of which a total of 269 DEGs and 4 DELs were identified to be methylation driven. Least absolute shrinkage and selection operator analysis screened that 14 methylation-driven genes were significantly associated with overall survival (OS) and thus were used as a signature to establish a prognostic risk model. Based on the median threshold, the patients were divided into the low-risk and the high-risk groups, which showed significantly different survival periods under the Kaplan-Meier curve. The area under receiver operating characteristic curve (AUC) was 0.934, 0.919, and 0.952 for the training, validation, and entire cohort, respectively. Stratification analysis showed that the established risk model may add prognostic values to conventional clinical factors (age, neoplasm histologic grade, and clinical stage). A nomogram was constructed based on the risk model and clinical parameters, with the AUC of 0.978 and c-index of 0.8079. Database for Annotation, Visualization, and Integrated Discovery (DAVID) function enrichment and Human Protein Atlas (HPA) protein expression validation showed 5 of these 14 genes may be especially important for UCEC (hypermethylated lowly expressed: CCBE1, FOXL2, PHLDB2, and DTNA; hypomethylated highly expressed: CCNE1). Comparison with breast cancer in the methylation level indicated ABCA12, CCNE1, and CLRN3 may be specific methylation-driven genes for UCEC. LncRNA HCG11 may function by coexpressing with DTNA. In conclusion, this 14-DNA methylation signature combined with clinical factors may a potentially effective biomarker in predicting OS for UCEC patients.

Predictors of live birth rate in women with diminished ovarian reserve.

OBJECTIVE: To investigate the chance of live birth after several oocyte retrieval cycles in patients with diminished ovarian reserve (DOR) and identify the possible predictors. METHODS: A retrospective analysis of 931 patients with DOR who underwent in vitro fertilization at a university hospital in China between January 2012 and December 2014. All data for fresh and the associated frozen-thawed embryo transfer attempts were analyzed. Conditional and cumulative live birth rates (LBRs) were calculated. Mediation and logistic regression analyses were performed to determine the predictors of live birth. RESULTS: Conditional LBRs remained around 10.0% in the first five cycles. Conservative cumulative LBRs (CLBRs) reached 22.0% after three cycles and increased to 24.8% after six cycles; optimal CLBRs increased from 12.9% to nearly 50.0% after six cycles. Patient age and the number of good-quality embryos were two key predictors in determining the conditional and conservative LBRs. CONCLUSION: For patients with DOR, conditional LBR remained constant in the first five cycles, and patients should be encouraged to continue to three or five completed cycles to maximize their chance of live birth. Patient age and the number of good-quality embryos were two key factors to predict live birth.

Suppressive Effects of Ursolic Acid on Human Endometriotic Stromal Cells Survival.

BACKGROUND/AIMS: The identification of new compound candidates for endometriosis treatment is needed. Cyclooxygenase-2 (COX-2) is considered a crucial target to control the progress and recurrence of endometriosis. Here, we identified ursolic acid (UA) as a natural inhibitor of COX-2 and investigated its effects on endometriosis progression. METHODS: Primary human endometriotic stromal cells isolated from patients with endometriosis were exposed to UA at concentrations of 15, 30, 45, and 60 µM. 3-(4,5-Dimethylthiaziazol-2-yl)-2,5-diphenyl tetrazolium bromide assays, 5'-bromo-2'-deoxy-uridine assays, and Caspase-3 activity measurements were performed to detect cell growth and apoptosis. Enzyme-linked immunosorbent assays were used to detect COX-2 and vascular endothelial growth factor (VEGF) protein expression and prostaglandin E2 (PGE2) levels. Capillary-tubule formation assays using human umbilical vein endothelial cells were also carried out to determine angiogenesis. RESULTS: UA significantly decreased cell viability, inhibited proliferation, and increased caspase-3 activity in a dose-dependent manner. COX-2 protein expression and the subsequent PGE2 production were both reduced by UA. Meanwhile, UA exposure decreased VEGF secretion in the stromal cells and the capillary-tubule formation assay confirmed the inhibitory effect of UA on angiogenesis. Furthermore, UA increased the phosphorylation of c-Jun N-terminal kinase and p38. CONCLUSIONS: Our data suggest that UA plays a role as a natural inhibitor of COX-2 to control the survival of human endometriotic stromal cells by inhibiting proliferation and angiogenesis and promoting apoptosis.

miR-92a promotes progesterone resistance in endometriosis through PTEN/AKT pathway.

The alteration of PTEN expression may be a vital part of the pathological and physiological mechanisms in infertility-related with endometriosis. However, the potential mechanisms underlying abnormal expression of PTEN and its role in progesterone-resistant endometriosis have not been thoroughly elucidated. In this study, our data showed the PTEN messenger RNA (mRNA) level and protein expression was reduced in progesterone-resistant endometriosis tissue and primary stomal cells. Low levels of PTEN in endometrial stromal cells led to higher cell proliferation and resistance to progesterone. In terms of PTEN suppression in progesterone-resistant endometriosis, the mRNA level of miR-92a was correlated negatively with PTEN level. Transfection of miR-92a mimic reduced PTEN expression and made the stromal cells more resistant to progesterone treatment. Inhibition of miR-92a by its antagomir had the opposite effects. Results of the luciferase reporter assay for the 3'-nontranslated region suggested that miR-92a directly modulated PTEN levels. Moreover, miR-92a inhibition by its antagomir enhanced the therapeutic effect of progesterone, which suppressed stromal cell proliferation, and reduced the formation of ectopic lesions in the mouse model of endometriosis. Hence, this study revealed that miR-92a contributed to the development of progesterone resistant endometriosis by suppression of PTEN expression, and modulation of miR-92a might be a potential medical method of treating endometriosis.

Increased expression and altered methylation of HERVWE1 in the human placentas of smaller fetuses from monozygotic, dichorionic, discordant twins.

BACKGROUND: The human endogenous retroviral family W, Env(C7), member 1 gene (HERVWE1) is thought to participate in trophoblast cell fusion, and its expression is diminished in the placentas of singleton intrauterine growth-retarded pregnancies. However, there is limited information about the role of HERVWE1 in discordant fetal growth in twins. This study was to compare HERVWE1 gene expression between the placentas of discordant monozygotic twins and to identify its regulation by methylation. METHODOLOGY/PRINCIPAL FINDINGS: Fetuses from twenty-one pairs of monozygotic, dichorionic, discordant twins were marked as "smaller" or "larger" according to birth weight. Placental HERVWE1 mRNA and protein expression profiles were analyzed using quantitative RT-PCR and immunohistochemistry (IHC) staining. Methylation profiles of the HERVWE1 promoter region were analyzed using a pyrosequencing assay. DNA methyltransferase (DNMT) transcript levels were analyzed by RT-PCR. 5-methyl cytosine (5-MC) was stained using an immunohistochemical assay. There was a significant negative correlation between HERVWE1 mRNA levels and birth weight in twins (P<0.01). Whereas the mean methylation level of the HERVWE1 promoter region was diminished in the smaller group in discordant twins(P<0.01), increased mRNA and protein levels of HERVWE1 were found in smaller fetuses compared with larger fetuses in discordant twins(P<0.01). There was no significant difference in 5-MC staining intensity between discordant twins (P>0.05). The DNMT3b3 mRNA levels in the smaller group were significantly downregulated compared with the larger group in discordant twins(P<0.05), whereas the DNMT3b7 mRNA levels in the smaller group were significantly upregulated compared with the larger group in discordant twins(P<0.05). CONCLUSIONS/SIGNIFICANCE: In discordant, monozygotic, dichorionic twins, HERVWE1 expression was higher in smaller fetuses and lower in larger fetuses. Methylation of the HERVWE1 gene promoter region may participate in the regulation of HERVWE1 gene expression in discordant twin pregnancies.

[Expression and methylated regulation of HERVWE1 in placenta of monozygotic discordant twins].

OBJECTIVE: To explore the HERVWE1 gene expression in the placentas of discordant monozygotic twins and identify its regulation by methylation. METHODS: Fetuses from 21 pairs of monozygotic discordant twins were marked as "smaller" or "larger" according to birth weight. Placental HERVWE1 mRNA and protein expression profiles were analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) stain. Methylation profiles of the HERVWE1 promoter region were analyzed by COBRA, MSP-PCR and pyrosequencing assay. RESULTS: In discordant twins group, the mean methylation level of the HERVWE1 promoter region decreased in smaller fetuses (P < 0.05). And there were increased mRNA and protein levels of HERVWE1 in smaller fetuses versus larger counterparts (P < 0.05). CONCLUSION: In discordant monozygotic twins, the HERVWE1 expression is higher in smaller fetuses and lower in larger counterparts. Methylation of HERVWE1 gene promoter region may participate in the regulation of HERVWE1 gene expression in twins.

Selective and non-selective intrauterine growth restriction in twin pregnancies: high-risk factors and perinatal outcome.

PURPOSE: To evaluate the high-risk factors and perinatal outcome in selective intrauterine growth restriction (sIUGR) and non-selective IUGR (non-sIUGR) in twins. METHODS: In total, 336 pairs of twins were enrolled from December 2003 to 2009. According to the birth weight, 295 pairs of twins were divided into sIUGR, non-sIUGR and normal growth groups. Maternal characteristics, complications, chorionicity, zygosity and perinatal outcomes were analyzed among the three groups. RESULTS: The overall IUGR incidence (including sIUGR and non-sIUGR) in twin pregnancies was 23.2%. The sIUGR incidence was ten times greater than that of non-sIUGR. Monochorionicity and monozygosity were risk factors for overall IUGR, especially for the sIUGR (P < 0.01). Pre-eclampsia was more common in sIUGR than in the normal growth group (P < 0.05). Both the sIUGR and non-sIUGR groups had more intrauterine fetal death and neonatal death than the normal growth group (P < 0.01). The sIUGR group had more brain injury than the normal growth group (P < 0.01). CONCLUSION: Monochorionicity, monozygosity, pre-eclampsia were high-risk factors for IUGR in twins. Perinatal death was more prevalent in the non-sIUGR group, and neonatal brain damage was more prevalent in the sIUGR group.