Is there an increased risk of preeclampsia after Frozen-thawed Embryo Transfer(FET) compared to In Vitro Fertilization-fresh transfer(IVF-fresh-ET) according to endometrial type of preparation for FET? The frequency of preeclampsia and... more
Is there an increased risk of preeclampsia after Frozen-thawed Embryo Transfer(FET) compared to In Vitro Fertilization-fresh transfer(IVF-fresh-ET) according to endometrial type of preparation for FET? The frequency of preeclampsia and hypertension were significantly higher in the group of artificial cycle (AC-FET) compared to ovulatory cycle (OC-FET) and fresh-ET (P < 0.0001). Risks of maternal morbidity are known to be reduced in pregnancies resulting from FET compared to fresh-ET except for the risk of preeclampsia, that was reported to be significantly higher in pregnancies resulting from FET compared to fresh-ET or spontaneous conception. Most recent studies demonstrate an equal live birth rate with either OC-FET or AC-FET preparation. Few studies compared the maternal vascular morbidities with the two hormonal environments that preside over the early stages of embryonic development: OC (major role of the corpus luteum) and AC (prolonged hormone replacement with high doses o...
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Cryoconservation of gametes : how to perform ? The patients can preserve their gametes when they are exposed to potential gonadotoxic pathology or treatment. In this context, the French bioethical law clearly states the obligation to... more
Cryoconservation of gametes : how to perform ? The patients can preserve their gametes when they are exposed to potential gonadotoxic pathology or treatment. In this context, the French bioethical law clearly states the obligation to inform the patients about the risks for their fertility and the possibilities to cryopreserve their gametes. Regional platforms of fertility preservation allow notably for the coordination of the oncology teams and the CECOS. For the men, sperm freezing is achieved by a slow and controlled temperature protocol. For the women, the oocytes are usually vitrified after hormonal stimulation and ovarian punction. For both, the gametes are cryopreserved in straws and stored in liquid nitrogen until use in assisted reproductive treatment (ART). Each year, the CECOS keeping the gametes interrogates patients on their wish to continue, or not, the cryoconservation. The gametes can only be used in ART by the patients only during their lifetime and with their consen...
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The causes of male infertility may be identified, with the possibility of drugs treatment, or they may be idiopathic, for which treatments are at the research stage. The treatments available aim to increase the quantity and quality of... more
The causes of male infertility may be identified, with the possibility of drugs treatment, or they may be idiopathic, for which treatments are at the research stage. The treatments available aim to increase the quantity and quality of spermatozoa produced by increasing their fertilising capacity and protecting their nuclear structure. Hormone treatments - recombinant FSH, purified FSH - give different results depending on whether studies examine semen parameters or fertilisation and pregnancy rates. In the case of non-hormone treatments (folates, zinc, vitamins E or C, selenium, glutathione and carnitine), the data in the literature is also contradictory and there is no clear consensus of opinion. However, the studies make use of highly variable methodologies and many of them are non-randomised. In terms of hygiene and dietary measures, tobacco, alcohol and excess weight have a negative effect on semen parameters and it is relevant to encourage patients to adopt a healthier lifestyle.
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<b>Copyright information:</b>Taken from "Assisted Reproductive Technology affects developmental kinetics, Imprinting Control Region methylation and gene expression in individual mouse... more
<b>Copyright information:</b>Taken from "Assisted Reproductive Technology affects developmental kinetics, Imprinting Control Region methylation and gene expression in individual mouse embryos"http://www.biomedcentral.com/1471-213X/7/116BMC Developmental Biology 2007;7():116-116.Published online 18 Oct 2007PMCID:PMC2169233.y and degree of expansion). The results were expressed as a percentage of the total blastocyst number. In the same experimental group (C or D), significant differences of maturity degree were observed according to the culture medium (χtest, P &lt; 0.05)
Modulation of imprinted gene network in placenta results in normal development of in vitro
Background To the best of our knowledge, no study has exhaustively evaluated the association between maternal morbidities and Coronavirus Disease 2019 (COVID-19) during the first wave of the pandemic in pregnant women. We investigated, in... more
Background To the best of our knowledge, no study has exhaustively evaluated the association between maternal morbidities and Coronavirus Disease 2019 (COVID-19) during the first wave of the pandemic in pregnant women. We investigated, in natural conceptions and assisted reproductive technique (ART) pregnancies, whether maternal morbidities were more frequent in pregnant women with COVID-19 diagnosis compared to pregnant women without COVID-19 diagnosis during the first wave of the COVID-19 pandemic. Methods and findings We conducted a retrospective analysis of prospectively collected data in a national cohort of all hospitalizations for births ≥22 weeks of gestation in France from January to June 2020 using the French national hospitalization database (PMSI). Pregnant women with COVID-19 were identified if they had been recorded in the database using the ICD-10 (International Classification of Disease) code for presence of a hospitalization for COVID-19. A total of 244,645 births w...
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Children conceived by assisted reproductive technologies (ART) have a moderate risk for a number of adverse events and conditions. The question whether this additional risk is associated with specific procedures used in ART or whether it... more
Children conceived by assisted reproductive technologies (ART) have a moderate risk for a number of adverse events and conditions. The question whether this additional risk is associated with specific procedures used in ART or whether it is related to the intrinsic biological factors associated with infertility remains unresolved. One of the main hypotheses is that laboratory procedures could have an effect on the epigenome of gametes and embryos. This suspicion is linked to the fact that ART procedures occur precisely during the period when there are major changes in the organization of the epigenome. Oocyte freezing protocols are generally considered safe; however, some evidence suggests that vitrification may be associated with modifications of the epigenetic marks. In this manuscript, after describing the main changes that occur during epigenetic reprogramming, we will provide current information regarding the impact of oocyte vitrification on epigenetic regulation and the conse...
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STUDY QUESTION Do assisted reproductive technologies (ART) and in vitro embryo culture influence the epigenetic control of imprinted genes (IGs) and transposable elements (TEs) in children? SUMMARY ANSWER Significant differences in the... more
STUDY QUESTION Do assisted reproductive technologies (ART) and in vitro embryo culture influence the epigenetic control of imprinted genes (IGs) and transposable elements (TEs) in children? SUMMARY ANSWER Significant differences in the DNA methylation of IGs or transposon families were reported between ART and naturally conceived children, but there was no difference between culture media. WHAT IS KNOWN ALREADY There is concern that ART may play a role in increasing the incidence of adverse health outcomes in children, probably through epigenetic mechanisms. It is crucial to assess epigenetic control, especially following non-optimal in vitro culture conditions and to compare epigenetic analyses from ART-conceived and naturally conceived children. STUDY DESIGN, SIZE, DURATION This follow-up study was based on an earlier randomized study comparing in vitro fertilization outcomes following the use of two distinct culture media. We compared the epigenetic profiles of children from the ...
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Children conceived through assisted reproductive technologies (ART) now account for a noteworthy proportion (-2.4%) of births in France. Considerable attention is being paid to the outcome of ART pregnancies. The vast majority of these... more
Children conceived through assisted reproductive technologies (ART) now account for a noteworthy proportion (-2.4%) of births in France. Considerable attention is being paid to the outcome of ART pregnancies. The vast majority of these children are apparently normal. However, they are at an increased risk of minor birth defects, low birth weight, and rare imprinting disorders such as Beckwith-Wiedemann syndrome (BWS), Angelman syndrome (AS) and Silver Russel syndrome (SRS). Animal models are important for investigating the possible role of each step of ART (ovarian stimulation, gamete manipulation, in vitro fertilization, embryo culture and embryo transfer) in epigenetic reprogramming This review discusses these issues in the context of epigenetic and developmental abnormalities observed in animals following ART More research is needed on ART-induced errors, focusing not only on genomic imprinting but also on non-imprinted loci, which may help explain some of the more subtle longer-term health effects emerging from studies with animal models.
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To study whether the closed culture system, as compared with a benchtop incubator with similar culture conditions, has a positive impact on intracytoplasmic sperm injection (ICSI) outcomes. Randomized controlled trial. University... more
To study whether the closed culture system, as compared with a benchtop incubator with similar culture conditions, has a positive impact on intracytoplasmic sperm injection (ICSI) outcomes. Randomized controlled trial. University hospital. A total of 386 patients undergoing ICSI cycles with at least six mature oocytes were randomized. Of these patients, 195 were assigned to the group with culture in a time-lapse imaging (TLI) system (EmbryoScope) and 191 to the group with culture in the G185 K-System (G185). Rate of implantation (primary endpoint) and embryo morphology grade. No significant differences were found in the implantation rates. The proportion of high-grade embryos on day 2 was significantly higher in the TLI group compared with the G185 group (40.4% vs. 35.2%). The impact of the incubator on embryo morphology remained significant in multivariate analysis, which took into account the woman's age, the rank of attempt, and the smoking status (TLI vs. G185: odds ratio = ...
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Do assisted reproductive technologies alter DNA methylation and/or transcription of transposable elements and imprinted genes in cord blood and placenta? After ART, DNA methylation and/or transcription changes of some transposable... more
Do assisted reproductive technologies alter DNA methylation and/or transcription of transposable elements and imprinted genes in cord blood and placenta? After ART, DNA methylation and/or transcription changes of some transposable elements and imprinted genes were found in placenta samples while transcription modifications for some transposable elements were also discovered in cord blood. Recent studies have confirmed the increased risk of placenta-related adverse pregnancy outcomes and the excess of imprinted disorders with abnormal methylation patterns after ART, which raises the issue of a potential ART-induced epigenetic risk. A total of 51 IVF/ICSI (15 conventional and 36 ICSI) singleton pregnancies were prospectively included from January 2013 to April 2015 and compared to 48 spontaneously conceived singleton pregnancies. The DNA methylation and transcription of three imprinted loci (H19/IGF2, KCNQ1OT1 and SNURF DMRs) and four transposon families (LINE-1, ERVFRD, AluYa5 and ER...
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Progress in assisted reproductive technologies strongly relies on understanding the regulation of the dialogue between oocyte and cumulus cells (CCs). Little is known about the role of long non-coding RNAs (lncRNAs) in the human... more
Progress in assisted reproductive technologies strongly relies on understanding the regulation of the dialogue between oocyte and cumulus cells (CCs). Little is known about the role of long non-coding RNAs (lncRNAs) in the human cumulus-oocyte complex (COC). To this aim, publicly available RNA-sequencing data were analyzed to identify lncRNAs that were abundant in metaphase II (MII) oocytes (BCAR4, C3orf56, TUNAR, OOEP-AS1, CASC18, and LINC01118) and CCs (NEAT1, MALAT1, ANXA2P2, MEG3, IL6STP1, and VIM-AS1). These data were validated by RT-qPCR analysis using independent oocytes and CC samples. The functions of the identified lncRNAs were then predicted by constructing lncRNA-mRNA co-expression networks. This analysis suggested that MII oocyte lncRNAs could be involved in chromatin remodeling, cell pluripotency and in driving early embryonic development. CC lncRNAs were co-expressed with genes involved in apoptosis and extracellular matrix-related functions. A bioinformatic analysis ...
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To evaluate the ART results with sperm donation for couples who do not succeed after IC ICSI treatment for male infertility. Retrospective study of 71 couples (November 1994-February 2009). Two control populations were determined to... more
To evaluate the ART results with sperm donation for couples who do not succeed after IC ICSI treatment for male infertility. Retrospective study of 71 couples (November 1994-February 2009). Two control populations were determined to analyse this two-steps treatment (IC and sperm donation) based on different criteria such as the date of ICSI, the female age at the time of the first attempt and the male indication. In IC-ICSI, the proportion of azoospermic subjects and/or carrying chromosomal abnormalities was significantly higher in the studied population as compared to control. The fertilization rate (FR) and the embryo quality were significantly lower in the studied population. After donation, 30 couples (42.2%) succeeded in being parents. The donor IA pregnancy rates were similar to those of the control population except for the azoospermic patients with poor results. When IVF/ICSI-D was performed, the pregnancy rates were lower than in the control population. Sperm donation const...
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Research Interests: Andrology, Kinetics, Health, Fetal development, Pregnancy, and 15 moreHumans, Female, Intracytoplasmic Sperm Injection, Male, Embryo Transfer, Newborn Infant, Fertility Rate, Fertilization, Embryonic Development, Retrospective Studies, Reproductive, Embryos, Pregnancy Rate, Pregnancy Outcome, and Paediatrics and reproductive medicine
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The pregnancy outcome and the chances of birth were assessed according to embryo quality after IVF or ICSI. The implantation rate (IR), the loss of gestational sacs rate (LGSR), and birth rate (BR) were determined according to the... more
The pregnancy outcome and the chances of birth were assessed according to embryo quality after IVF or ICSI. The implantation rate (IR), the loss of gestational sacs rate (LGSR), and birth rate (BR) were determined according to the cleavage stage and the integrity of blastomeres after day-2 homogeneous embryo transfers (n = 1812). The LGSR was higher after transfers of 2-3-cell or 5-6-cell embryos and was significantly increased when more than 20% of the embryo volume was fragmented in 4-cell embryos. After transfers of 4-cell embryos without fragmentation, the BR was significantly higher than the BR after transfers of 4-cell embryos with 1-20% fragmentation (16.6% vs 13.1%). The difference was the consequence of a higher IR (20.4% vs 17.3%) but also of a lower LGSR (18.9% vs 24.2%). Not only implantation and the ability to give a pregnancy, but also the capacity to give a live birth are dependent on the embryo quality.
Research Interests: Genetics, Obstetrics, Medicine, Pregnancy, Humans, and 14 moreFemale, Assisted Reproduction, Embryo Transfer, Newborn Infant, Adult, Fertilization in Vitro, Embryos, Fetal death, Pregnancy Outcome, Embryo Development, Assisted, Embryo disposition, embryo implantation, and Paediatrics and reproductive medicine
Objectives. To analyze the impact of oocyte denudation and microinjection timings on intracytoplasmic sperm injection (ICSI) outcomes. Study Design. We included ICSI cycles with the following parameters: rank 1 or 2, female age <36... more
Objectives. To analyze the impact of oocyte denudation and microinjection timings on intracytoplasmic sperm injection (ICSI) outcomes. Study Design. We included ICSI cycles with the following parameters: rank 1 or 2, female age <36 years, male factor infertility, long protocol using GnRH agonist and rFSH for ovarian stimulation, and use of freshly ejaculated sperm (n = 110). Several ICSI parameters were analyzed according to the time between oocyte retrieval and denudation (T(1)) and the time between denudation and ICSI (T(2)) using a statistical logistic regression analysis. Results. Neither T(1) nor T(2) had a significant influence on the Metaphase II (MII) rate but the fertilisation rate (FR) showed a significant improvement when T(1) was longer (optimal results at T(1) = 3 hours) while FR significantly decreased with the increase of T(2). Optimal implantation (IR) and pregnancy (PR) rates were obtained when T(1) was around 2 hours. Conclusion. Incubation of oocytes around 2 h...
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Research Interests: Biology, Genomic Imprinting, Medicine, Embryo, Biological Sciences, and 15 moreMice, Methylation, Female, Animals, In Vitro Fertilization, Human Molecular Genetics, DNA methylation, Blastocyst, Gene Network, Gene Regulatory Networks, Embryonic Development, Imprinting Psychology, Fertilization in Vitro, Medical and Health Sciences, and In Vitro Techniques
Research Interests: Obstetrics, Treatment Outcome, Medicine, Soft Tissue Preservation, Pregnancy, and 15 moreHumans, Fertility and Sterility, Female, Male, Embryo Transfer, Clinical Sciences, Newborn Infant, Adult, Public health systems and services research, Oocytes, Freezing, Twin Pregnancy, Cumulant, Assisted Reproductive Technique, and Paediatrics and reproductive medicine
Research Interests: Treatment Outcome, Infertility, Medicine, HIV, Pregnancy, and 14 moreHumans, Fertility and Sterility, Female, Male, Body Mass Index, Clinical Sciences, Adult, Public health systems and services research, Time Factors, Retrospective Studies, Age Factors, Hiv seropositivity, Case Control Studies, and Paediatrics and reproductive medicine
Research Interests: Andrology, Infertility, Medicine, Oogenesis, Pregnancy, and 15 moreHumans, Fertility and Sterility, Female, Ovulation Induction, Male, Embryo Transfer, Clinical Sciences, Adult, Public health systems and services research, Time Factors, Polar Body, Oocytes, Embryos, Live birth, and Paediatrics and reproductive medicine
Research Interests: Multivariate Analysis, Embryo, Birth, Pregnancy, Humans, and 14 moreFertility and Sterility, Female, Blastocyst, Clinical Sciences, Cell nucleus, Embryonic Development, Public health systems and services research, Retrospective Studies, Prognosis, Fertilization in Vitro, Pregnancy Rate, Predictive value of tests, embryo implantation, and Paediatrics and reproductive medicine
Research Interests: Treatment Outcome, Medicine, Pregnancy, Humans, Fertility and Sterility, and 15 moreFemale, Ovulation Induction, Assisted Reproduction, Clinical Sciences, Adult, Public health systems and services research, Endometriosis, Gonadotropin Releasing Hormone, Prognosis, Elsevier, Female Infertility, Oral Contraceptive, Combined Modality Therapy, Uterine diseases, and Paediatrics and reproductive medicine
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A stimulatory DNA methyltransferase co-factor, Dnmt3L, has evolved in mammals to assist the process of de novo methylation, as genetically demonstrated in the germline. The function of Dnmt3L in the early embryo remains unresolved. By... more
A stimulatory DNA methyltransferase co-factor, Dnmt3L, has evolved in mammals to assist the process of de novo methylation, as genetically demonstrated in the germline. The function of Dnmt3L in the early embryo remains unresolved. By combining developmental and genetic approaches, we find that mouse embryos begin development with a maternal store of Dnmt3L, which is rapidly degraded and does not participate in embryonic de novo methylation. A zygotic-specific promoter of Dnmt3l is activated following gametic methylation loss and the potential recruitment of pluripotency factors just before implantation. Importantly, we find that zygotic Dnmt3L deficiency slows down the rate of de novo methylation in the embryo by affecting methylation density at some, but not all, genomic sequences. Dnmt3L is not strictly required, however, as methylation patterns are eventually established in its absence, in the context of increased Dnmt3A protein availability. This study proves that the postimpla...
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Research Interests: Kinetics, Biology, Genomic Imprinting, Epigenetics, Medicine, and 14 moreGene expression, Biological Sciences, Methylation, In Vitro Fertilization, DNA methylation, Experimental Study, Imprinting Psychology, Developments In Assisted Reproduction Technology, Embryos, Embryo Development, culture medium, Experimental Group, Medical and Health Sciences, and Embryo Culture
STUDY QUESTION Do IVF, IUI or female infertility (i.e. endometriosis, polycystic ovary syndrome [PCOS] and primary ovarian insufficiency [POI]) lead to an increased risk of congenital anomalies in singletons? SUMMARY ANSWER After... more
STUDY QUESTION Do IVF, IUI or female infertility (i.e. endometriosis, polycystic ovary syndrome [PCOS] and primary ovarian insufficiency [POI]) lead to an increased risk of congenital anomalies in singletons? SUMMARY ANSWER After multivariable adjustments, the increased risks of congenital defects associated with IUI were no longer significant, but the underlying maternal infertility presented a potential emental risk, in addition to the risk associated with IVF. WHAT IS KNOWN ALREADY Most epidemiological studies suggest that singletons born from ART have a higher risk of birth defects, specifically musculoskeletal, cardiovascular and urogenital disorders. However, most of these studies were established on data obtained at birth or in the neonatal period and from relatively small populations or several registries. Moreover, to our knowledge, female infertility, which is a potential confounder, has never been included in the risk assessment. STUDY DESIGN, SIZE, DURATION Using data fr...
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Today, there is growing interest in the potential epigenetic risk related to assisted reproductive technologies (ART). Much evidence in the literature supports the hypothesis that adverse pregnancy outcomes linked to ART are associated... more
Today, there is growing interest in the potential epigenetic risk related to assisted reproductive technologies (ART). Much evidence in the literature supports the hypothesis that adverse pregnancy outcomes linked to ART are associated with abnormal trophoblastic invasion. The aim of this review is to investigate the relationship between epigenetic dysregulation caused by ART and subsequent placental response. The dialogue between the endometrium and the embryo is a crucial step to achieve successful trophoblastic invasion, thus ensuring a non-complicated pregnancy and healthy offspring. However, as described in this review, ART could impair both actors involved in this dialogue. First, ART may induce epigenetic defects in the conceptus by modifying the embryo environment. Second, as a result of hormone treatments, ART may impair endometrial receptivity. In some cases, it results in embryonic growth arrest but, when the development of the embryo continues, the placenta could bring adaptive responses throughout pregnancy. Amongst the different mechanisms, epigenetics, especially thanks to a finely tuned network of imprinted genes stimulated by foetal signals, may modify nutrient transfer, placental growth and vascularization. If these coping mechanisms are overwhelmed, improper maternal-foetal exchanges occur, potentially leading to adverse pregnancy outcomes such as abortion, preeclampsia or intra-uterine growth restriction. But in most cases, successful placental adaptation enables normal progress of the pregnancy. Nevertheless, the risks induced by these modifications during pregnancy are not fully understood. Metabolic diseases later in life could be exacerbated through the memory of epigenetic adaptation mechanisms established during pregnancy. Thus, more research is still needed to better understand abnormal interactions between the embryo and the milieu in artificial conditions. As trophectoderm cells are in direct contact with the environment, they deserve to be studied in more detail. The ultimate goal of these studies will be to render ART protocols safer. Optimization of the environment will be the key to improving the dialogue between the endometrium and embryo, so as to ensure that placentation after ART is similar to that following natural conception.
The case of a successful pregnancy is reported here, following intracytoplasmic sperm injection which resulted in a cohort of embryos showing accelerated cleavage kinetics. Pregnancy was not achieved with fresh embryos transferred at the... more
The case of a successful pregnancy is reported here, following intracytoplasmic sperm injection which resulted in a cohort of embryos showing accelerated cleavage kinetics. Pregnancy was not achieved with fresh embryos transferred at the 4-cell stage but was achieved with cryopreserved accelerated embryos. After an ovarian stimulation cycle, 20 mature oocytes were observed. Early cleavage was observed in 19 of these, 26 h post-injection, and 17 were beyond the 4-cell stage 42 h after injection. No pregnancy was obtained after the transfer of two fresh embryos at the 4-cell stage without fragments. Following the transfer of two frozen accelerated embryos, a twin pregnancy was obtained, which resulted in the delivery of two healthy babies. This case report demonstrates that classical scoring systems may need to be adapted to reflect the cleavage kinetics of the whole embryo cohort.
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Erectile dysfunction, ejaculatory dysfunction and poor semen quality are the main causes of infertility in men with spinal cord injury (SCI). Different sperm retrieval techniques such as penile vibratory stimulation (PVS),... more
Erectile dysfunction, ejaculatory dysfunction and poor semen quality are the main causes of infertility in men with spinal cord injury (SCI). Different sperm retrieval techniques such as penile vibratory stimulation (PVS), electro-ejaculation (EEJ) or surgical sperm retrieval (SSR) associated or not with sperm cryopreservation can be offered to these patients to preserve their fertility. If fatherhood cannot be achieved naturally, assisted reproductive techniques can be offered to these patients using either fresh or frozen/thawed sperm. The aim of the study was to report in SCI patients from Dijon (Burgundy) and in the literature, intracytoplasmic sperm injection (ICSI) outcomes using frozen sperm obtained either by antegrade ejaculation (PVS or sexual intercourse) or by SSR. A retrospective analysis was performed in Dijon, Burgundy over a 17 year period (1995-2011) on a cohort of 19 SCI men (6 quadriplegics and 13 paraplegics, mean age: 25.2 ± 5.6 years) who underwent a sperm cryopreservation followed or not by intracytoplasmic sperm injection (ICSI). Patients were divided into two groups according to the sperm retrieval method used (antegrade ejaculation group (n=10): penile vibratory stimulation (PVS) for 9 patients and sexual intercourse for 1 patient and surgical sperm retrieval (SSR) group: n=9). The sperm parameters in both groups were analyzed. Pregnancy outcomes in the 8 couples who underwent ICSI were evaluated. The fertilization rates were 57 and 55%, the embryo&amp;amp;amp;amp;amp;amp;amp;amp;#39;s cleavage rates were 90 and 93% in the antegrade ejaculation and SSR groups respectively. Among the 8 couples who underwent ICSI, 5 couples achieved pregnancy. The pregnancy rates per couple were 50% and 75% in the antegrade and SSR groups respectively. Although some studies don&amp;amp;amp;amp;amp;amp;amp;amp;#39;t recommend freezing sperm in SCI patients, the pregnancy rates presented in this study are encouraging and warrant the use of frozen/thawed sperm in very specific situations.
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X-chromosome inactivation (XCI) in female mammals allows dosage compensation for X-linked gene products between the sexes. The developmental regulation of this process has been extensively investigated in mice, where the X chromosome of... more
X-chromosome inactivation (XCI) in female mammals allows dosage compensation for X-linked gene products between the sexes. The developmental regulation of this process has been extensively investigated in mice, where the X chromosome of paternal origin (Xp) is silenced during early embryogenesis owing to imprinted expression of the regulatory RNA, Xist (X-inactive specific transcript). Paternal XCI is reversed in the inner cell mass of the blastocyst and random XCI subsequently occurs in epiblast cells. Here we show that other eutherian mammals have very different strategies for initiating XCI. In rabbits and humans, the Xist homologue is not subject to imprinting and XCI begins later than in mice. Furthermore, Xist is upregulated on both X chromosomes in a high proportion of rabbit and human embryo cells, even in the inner cell mass. In rabbits, this triggers XCI on both X chromosomes in some cells. In humans, chromosome-wide XCI has not initiated even by the blastocyst stage, despite the upregulation of XIST. The choice of which X chromosome will finally become inactive thus occurs downstream of Xist upregulation in both rabbits and humans, unlike in mice. Our study demonstrates the remarkable diversity in XCI regulation and highlights differences between mammals in their requirement for dosage compensation during early embryogenesis.
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To check the efficiency of the cryopreservation procedure by using trypan blue staining of ovarian test fragments to assess the quality of frozen-thawed ovarian tissue. Prospective study. University hospital. Patients with polycystic... more
To check the efficiency of the cryopreservation procedure by using trypan blue staining of ovarian test fragments to assess the quality of frozen-thawed ovarian tissue. Prospective study. University hospital. Patients with polycystic ovary syndrome undergoing laparoscopic ovarian drilling. Ovarian cortical biopsies obtained from polycystic ovary syndrome patients were frozen using a slow freezing-rapid thawing protocol. Primordial and primary follicle viability was assessed with trypan blue staining. Unstained isolated follicles were studied by transmission electron microscopy. Histologic and immunohistochemical analysis of apoptosis was performed on tissue sections. The percentage of unstained follicles considered live was lower (P=.015) after freezing/thawing (71.9%) than before cryopreservation (87.3%). Transmission electron microscopy on follicles considered live confirmed the lack of ultrastructural damage. After freezing/thawing, tissue morphology was preserved, but immunohistochemical analysis shows a significant increase in the apoptosis process. Ovarian cortical test fragments combined with trypan blue staining on enzymatically isolated follicles is a useful and quick method of assessing the initial quality and viability of follicles in cryopreserved ovarian tissue. This type of test should be used routinely as quality control in ovarian cryopreservation procedures.
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To review donor-egg assisted reproductive technology (ART) activity using young fertile donors (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;37 years of age) paired with multiple recipients. Age-matched cohort study.... more
To review donor-egg assisted reproductive technology (ART) activity using young fertile donors (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;37 years of age) paired with multiple recipients. Age-matched cohort study. Tertiary ART center at Cochin Hospital, Paris. A total of 125 oocyte donors and 361 age-matched control subjects. Donated oocytes were attributed to 163 different recipients undertaking 258 transfer cycles. Donor-egg and regular ART. Controlled ovarian hyperstimulation (COH) outcome-oocytes provided-was compared in donors and control subjects. Clinical pregnancy (cPR), ongoing pregnancy (oPR), and implantation (IR) rates per transfer in recipients were compared with age-matched controls. IRs were analyzed in the various recipients as a function of the number of oocytes harvested. COH outcome was similar in donors and control subjects. cPR (37.5%), oPR (28.4%), and IR (24.4%) were slightly but significantly lower in donor-egg recipients compared with control subjects (44.9%, 37.4%, and 31.8%, respectively). More embryos (average +2.06) were transferred fresh and fewer frozen. In recipients, IRs were independent from the number of oocytes received in the donor. Multiplying recipients paired with oocyte donors slightly lowered per-transfer outcome, but enabled more (average +2.06) embryos to be transferred fresh.
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Objectives. To analyze the impact of oocyte denudation and microinjection timings on intracytoplasmic sperm injection (ICSI) outcomes. Study Design. We included ICSI cycles with the following parameters: rank 1 or 2, female age <36... more
Objectives. To analyze the impact of oocyte denudation and microinjection timings on intracytoplasmic sperm injection (ICSI) outcomes. Study Design. We included ICSI cycles with the following parameters: rank 1 or 2, female age <36 years, male factor infertility, long protocol using GnRH agonist and rFSH for ovarian stimulation, and use of freshly ejaculated sperm (n = 110). Several ICSI parameters were analyzed according to the time between oocyte retrieval and denudation (T(1)) and the time between denudation and ICSI (T(2)) using a statistical logistic regression analysis. Results. Neither T(1) nor T(2) had a significant influence on the Metaphase II (MII) rate but the fertilisation rate (FR) showed a significant improvement when T(1) was longer (optimal results at T(1) = 3 hours) while FR significantly decreased with the increase of T(2). Optimal implantation (IR) and pregnancy (PR) rates were obtained when T(1) was around 2 hours. Conclusion. Incubation of oocytes around 2 h...