Oocyte maturation is a long process during which oocytes acquire their intrinsic ability to support the subsequent stages of development in a stepwise manner, ultimately reaching activation of the ...embryonic genome. This process involves complex and distinct, although linked, events of nuclear and cytoplasmic maturation. Nuclear maturation mainly involves chromosomal segregation, whereas cytoplasmic maturation involves organelle reorganization and storage of mRNAs, proteins and transcription factors that act in the overall maturation process, fertilization and early embryogenesis. Thus, for didactic purposes, we subdivided cytoplasmic maturation into: (1) organelle redistribution, (2) cytoskeleton dynamics, and (3) molecular maturation. Ultrastructural analysis has shown that mitochondria, ribosomes, endoplasmic reticulum, cortical granules and the Golgi complex assume different positions during the transition from the germinal vesicle stage to metaphase II. The cytoskeletal microfilaments and microtubules present in the cytoplasm promote these movements and act on chromosome segregation. Molecular maturation consists of transcription, storage and processing of maternal mRNA, which is stored in a stable, inactive form until translational recruitment. Polyadenylation is the main mechanism that initiates protein translation and consists of the addition of adenosine residues to the 3′ terminal portion of mRNA. Cell cycle regulators, proteins, cytoplasmic maturation markers and components of the enzymatic antioxidant system are mainly transcribed during this stage. Thus, the objective of this review is to focus on the cytoplasmic maturation process by analyzing the modifications in this compartment during the acquisition of meiotic competence for development.
BACKGROUND There is evidence that intrauterine growth restriction, resulting in newborn girls that are small for gestational age (SGA), may be related to the onset of polycystic ovary syndrome ...(PCOS). Thus, we studied whether women born SGA have a higher prevalence of PCOS than women born appropriate for gestational age (AGA). METHODS This was a prospective birth cohort study of 384 women born at term between June 1, 1978, and May 31, 1979, in Ribeirão Preto, Brazil. After exclusion, 165 women effectively participated in this study, of whom 43 were SGA and 122 were AGA. The prevalence of PCOS was analysed. At a mean age of 29 years, the women agreed to follow the study protocol, which included: anamnesis, physical examination, serum tests follicle stimulating hormone, luteinizing hormone, total and free testosterone, dehydroepiandrostenedione sulphate, 17-OH-progesterone, fasting insulin, sex steroid-binding globulin (SHBG) and fasting glucose and pelvic ultrasound. Data regarding gestational age, birthweight, age at menarche and maternal data were obtained from the files of the cohort. The adjusted relative risk (RR) values of the SGA, insulin resistance, body mass index, maternal smoking and parity variables were analysed using Poisson regression with robust adjustment of variance for the prediction of PCOS. RESULTS The prevalence of PCOS was higher in the SGA group than in the AGA group adjusted RR = 2.44, 95% CI (1.39–4.28). Hyperandrogenism was more prevalent in the SGA women than in the AGA women (P = 0.011). Circulating SHBG was lower in the SGA women than in the AGA women (P = 0.041), but fasting insulinemia was similar in both groups. CONCLUSIONS The prevalence of PCOS in SGA women was twice as high as in AGA women in our study population.
Assisted hatching (AH) is a manipulation of zona pellucida aiming to facilitate embryo implantation.
Systematic review and meta-analysis of medical literature was used to evaluate the effect of AH on ...assisted reproduction outcomes: clinical pregnancy, live birth, multiple pregnancy and miscarriage. Additional analysis was performed in these subgroups: (i) fresh embryos transferred to unselected or non-poor prognosis women; (ii) fresh embryos transferred to women with previous repeated failure; (iii) fresh embryos transferred to women of advanced age; (iv) frozen-thawed embryos transferred to unselected or non-poor prognosis women. Analyses were based on risk ratio and 95% confidence intervals (RR, 95% CIs) using Mantel-Haenszel random effects model.
There were 28 studies (5507 participants) included. AH was related to a trend toward increased clinical pregnancy for all participants (RR = 1.11, 95% CI = 1.00-1.24), with a significant increase in subgroups 2 (RR = 1.73; 95% CI = 1.37-2.17) and 4 (RR = 1.36; 95% CI = 1.08-1.72, P< 0.01), but not for subgroups 1 and 3. For multiple pregnancy, a significant increase was observed for all participants (RR = 1.45; 95% CI = 1.11-1.90) and for subgroups 2 (RR = 2.53; 95% CI = 1.23-5.21) and 4 (RR = 3.40; 95% CI = 1.93-6.01). No significant heterogeneity was observed in subgroup analysis.
AH was related to increased clinical pregnancy and multiple pregnancy rates in women with previous repeated failure or frozen-thawed embryos. However, AH is unlikely to increase clinical pregnancy rates when performed in fresh embryos transferred to unselected or non-poor prognosis women or to women of advanced age. Due to the small sample evaluated by the pool of included studies, no proper conclusions could be drawn regarding miscarriage or live birth.
Genomic imprinting alterations have been shown to be associated with assisted reproductive technologies (ARTs) in animals. At present, data obtained in humans are inconclusive; however, some ...epidemiological studies have demonstrated an increased incidence of imprinting disorders in children conceived by ARTs. In the present study, we focused on the effect of ARTs IVF and intracytoplasmic sperm injection (ICSI) on the epigenetic reprogramming of the maternally methylated imprinting control region KvDMR1 in clinically normal children. Qualitative and quantitative methylation at KvDMR1 were assessed by the methylation-specific PCR approach and by the methylation-sensitive enzymatic digestion associated with real-time PCR method, respectively. DNA was obtained from peripheral blood of 12/18 and umbilical cord blood and placenta of 6/18 children conceived by IVF or ICSI. The methylation patterns observed in this group were compared with the patterns observed in 30 clinically normal naturally conceived children (negative controls) and in 3 naturally conceived Beckwith–Wiedemann syndrome patients (positive controls). Hypomethylation at KvDMR1 was observed in 3/18 clinically normal children conceived by ARTs (2 conceived by IVF and 1 by ICSI). A discordant methylation pattern was observed in the three corresponding dizygotic twins. Our findings corroborate the hypothesis of vulnerability of maternal imprinting to ARTs. Furthermore, the discordant methylation at KvDMR1 observed between dizygotic twins could be consequent to one of the following possibilities: (i) a differential vulnerability of maternal imprints among different embryos; or (ii) epimutations that occurred during gametogenesis resulting in the production of oocytes without the correct primary imprint at KvDMR1.
BACKGROUND: The objective of this multicentre randomized, controlled clinical trial was to compare the efficacy of a levonorgestrel-releasing intrauterine system (LNG-IUS) and a depot-GnRH-analogue ...in the control of endometriosis-related pain over a period of six months. METHODS: Eighty-two women, 18 to 40 years of age (mean 30 years), with endometriosis, dysmenorrhoea and/or CPP, were randomized using a computer-generated system of sealed envelopes into either LNG-IUS (n=39) or GnRH analogue (n=43) treatment groups at three university centres. Daily scores of endometriosis-associated CPP were evaluated using the Visual Analogue Scale (VAS), daily bleeding score was calculated from bleeding calendars, and improvement in quality of life was evaluated using the Psychological General Well-Being Index Questionnaire (PGWBI). The pain score diary was based on the VAS in which women recorded the occurrence and intensity of pain on a daily basis. A monthly score was calculated from the result of the sum of the daily scores divided by the number of days in each observation period. RESULTS: CPP decreased significantly from the first month throughout the six months of therapy with both forms of treatment and there was no difference between the groups (P>0.999). In both treatment groups, women with stage III and IV endometriosis showed a more rapid improvement in the VAS pain score than women with stage I and II of the disease (P<0.002). LNG-IUS users had a higher bleeding score than GnRH-analogue users at all time points of observation with 34% and 71% of patients in the LNG-IUS and GnRH-analogue groups, respectively, reporting no bleeding during the first treatment month, and 70% and 98% reporting no bleeding during the sixth month. No difference was observed between groups with reference to improvement in quality of life. CONCLUSIONS: Both, the LNG-IUS and the GnRH-analogue were effective in the treatment of CPP-associated endometriosis, although no differences were observed between the two treatments. Among the additional advantages of the LNG-IUS is the fact that it does not provoke hypoestrogenism and that it requires only one medical intervention for its introduction every 5 years. This device could therefore become the treatment of choice for CPP-associated endometriosis in women who do not wish to conceive.
STUDY QUESTION
What is the potential impact of follicular fluid (FF) from infertile women with mild endometriosis (ME) on oocyte quality, especially on nuclear maturation and the meiotic spindle?
...SUMMARY ANSWER
FF from infertile women with ME may compromise nuclear maturation and the meiotic spindles of in vitro matured bovine oocytes.
WHAT IS KNOWN ALREADY
Controversial studies have suggested that impaired oocyte quality may be involved in the pathogenesis of endometriosis-related infertility. Moreover, some studies have demonstrated alterations in the composition of FF from infertile women with endometriosis. However, to date no study has evaluated the effect of FF from infertile women with ME on the genesis of meiotic oocyte anomalies.
STUDY DESIGN, SIZE, DURATION
We performed an experimental study. Samples of FF were obtained from February 2009 to February 2011 from 22 infertile women, 11 with ME and 11 with tubal or male factors of infertility (control group), who underwent ovarian stimulation for ICSI at our university IVF Unit. From March 2011 to February 2012 we performed in vitro maturation (IVM) experiments using immature bovine oocytes as described below.
PARTICIPANTS/MATERIALS, SETTING, METHODS
FF free of blood and containing a mature oocyte was obtained from 22 infertile women during oocyte retrieval for ICSI. Immature bovine oocytes underwent IVM in the absence of FF (No-FF) and in the presence of four concentrations (1, 5, 10 and 15%) of FF from infertile women without endometriosis (C-FF) and with ME (ME-FF). Eleven replicates were performed, each one using FF from a control patient and a patient with ME. Each FF sample was used in only one experiment. After 22–24 h of IVM, oocytes were denuded, fixed and immunostained for morphological visualization of microtubules and chromatin by confocal microscopy.
MAIN RESULTS AND THE ROLE OF CHANCE
A total of 1324 cumulus–oocyte complexes were matured in vitro. Of these, 1128 were fixed and 1048 were analyzed by confocal microscopy. The percentage of meiotically normal oocytes was significantly higher for oocytes that underwent IVM in the absence of FF (No-FF; 76.5%) and in the presence of 1% (80.9%), 5% (76.6%), 10% (75%) and 15% (76.2%) C-FF than in oocytes that underwent IVM in the presence of 1% (44.4%), 5% (36.7%), 10% (45.5%) and 15% (51.2%) ME-FF (P < 0.01). No differences were observed among FF concentrations within each group. When the four concentrations from each group were pooled, the number of oocytes in metaphase I stage was significantly higher in the ME-FF (50 oocytes) than in the C-FF (29 oocytes) group and the percentage of meiotic abnormalities was significantly higher when oocytes were matured with ME-FF (55.8%) than with C-FF (23.1%), P < 0.01.
LIMITATIONS, REASONS FOR CAUTION
Owing to the strict selection criteria for FF donors, this study had a small sample size (11 cases and 11 controls), and thus further investigations using a large cohort of patients are needed to confirm these results. In addition, data obtained from studies using animal models may not necessarily be extrapolated to humans and studies evaluating in vivo matured oocytes from infertile women with ME are important to confirm our results.
WIDER IMPLICATIONS OF THE FINDINGS
Our results open new insights into the pathogenic mechanisms of infertility related to mild endometriosis, suggesting that FF from infertile women with mild endometriosis may be involved in the worsening of oocyte quality of these women.
STUDY FUNDING/COMPETING INTEREST(S)
This study was supported by the National Council for Scientific and Technological Development (CNPq), Brazil. The authors declare no conflicts of interest.
BACKGROUND The objectives of this study were: (i) to evaluate the effects of the levonorgestrel-releasing intrauterine system (LNG-IUS) on both proliferation and apoptosis markers and hormone ...receptors of the eutopic and ectopic endometrium of women experiencing pain related to endometriosis and (ii) to compare the results with those obtained with GnRH agonist (GnRHa) injections. METHODS Pre- and post-treatment endometrium and endometriosis specimens were obtained from 22 women experiencing pain related to endometriosis who were treated with LNG-IUS (n = 11) or GnRHa (n = 11) for 6 months. Changes in the expression of proliferating cell nuclear antigen, Fas, progesterone receptor (PRA) and estrogen receptor α (ER-α) were analyzed by immunohistochemistry. RESULTS The cell proliferation index was significantly reduced in the epithelium and stroma of both the eutopic and the ectopic endometrium after treatment with the LNG-IUS and GnRHa. Only LNG-IUS users showed an increased H-score for Fas in the epithelium of the eutopic and ectopic endometrium (P < 0.05). Expression of ER-α and PRA by the glandular epithelium was lower in the eutopic endometrium after both treatments, but this reduction was noted in the ectopic endometrium only after LNG-IUS treatments (P < 0.05). No difference was detected between groups for any of the markers. CONCLUSIONS LNG-IUS reduced both cell proliferation and the expression of PRA and ER-α and increased Fas expression in the eutopic and ectopic endometrium of patients with endometriosis. Some of these actions were not observed with GnRHa.
Abstract
STUDY QUESTION
Compared to healthy women, is the profile of transcripts altered in the eutopic endometrium of infertile women with endometriosis during the implantation window (IW)?
SUMMARY ...ANSWER
The eutopic endometrium of infertile women with endometriosis seems to be transcriptionally similar to the endometrium of infertile and fertile controls (FC) during the IW.
WHAT IS KNOWN ALREADY
Endometriosis is a disease related to infertility; nevertheless, little is known regarding the ethiopathogenic mechanisms underlying this association. Some studies evaluating the eutopic endometrium of endometriosis patients suggest there is an endometrial factor involved in the disease-related infertility. However, no study to date has evaluated the endometrial transcriptome (mRNA and miRNA) by next generation sequencing (NGS), comparing patients with endometriosis as the exclusive infertility factor (END) to infertile controls (IC; male and/or tubal factor) and FC.
STUDY DESIGN, SIZE, DURATION
From November 2011 to November 2015 we performed a case-control study, where 17 endometrial samples (six END, six IC, five FC) were collected during the IW.
PARTICIPANTS/MATERIALS, SETTING, METHODS
All endometrial samples had the RNA extracted. Two libraries were prepared for each one (mRNA and miRNA), which were sequenced, respectively, at HISEQ 2500 (RNA-Seq) and MiSeq System (miRNA-Seq), Illumina. The normalization and differential expression were conducted in statistical R environment using DESeq2 package. qPCR was used for data validation, which were analyzed by Kruskal–Wallis test and Dunn posttest (P < 0.05).
MAIN RESULTS AND THE ROLE OF CHANCE
RNA-Seq revealed no differentially expressed genes (DEG) among END, IC and FC groups. miRNA-Seq revealed three differentially expressed miRNAs (has-27a-5p, has-miR-150-5p, has-miR-504-5p) in END group compared to FC group. However, none of the miRNAs identified in the sequencing was validated by qPCR.
LIMITATIONS, REASONS FOR CAUTION
The main limitation of this study was the small sample size evaluated as a result of the restrictive eligibility criteria adopted, limiting the generalization of the results obtained here. On the other hand, strict eligibility criteria, which eliminated factors potentially related to impaired endometrial receptivity, were required to increase the study’s internal validity.
WIDER IMPLICATIONS OF THE FINDINGS
This study brings new perspectives on the mechanisms involved in endometriosis-related infertility. The present findings suggest the eutopic endometrium of infertile women with endometriosis, without considering the disease’s stage, is transcriptionally similar to controls during the IW, possibly not affecting receptivity. Further studies are needed to evaluate endometrial alterations related to endometriosis’ stages.
STUDY FUNDING/COMPETING INTEREST(S)
This study received financial support from the Sao Paulo Research Foundation (FAPESP—Fundação de Amparo à Pesquisa do Estado de São Paulo; fellowship 2011/17614–6, MGB) and from the National Council for Scientific and Technological Development (CNPq—Conselho Nacional de Desenvolvimento Científico e Tecnológico; INCT—National Institutes of Hormones and Woman’s Health, grant 471 943/2012-6, 309 397/2016-2, PAN; fellowship 140 137/2015-7, MGB). The authors have no conflicts of interest.
TRIAL REGISTRATION NUMBER
N/A.
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