Biomedical subjects

J Remohí

Publications and source records attributed to J Remohí.

At least 37 records · Page 2Linked to original sources

PubMed2001

Increasing levels of estradiol are deleterious to embryonic implantation because they directly affect the embryo.

OBJECTIVE: To investigate whether the deleterious effect of E(2) on embryonic implantation is due to a direct effect on the endometrium, on the embryo, or both. DESIGN: Prospective, controlled in vitro study. SETTING: Tertiary infertility center. PATIENT(S): Fertile patients in the luteal phase with histologically normal endometrium who were attending the infertility clinic as oocyte donors (n = 14). INTERVENTION(S): E(2) dose-response (0, 10(-8), 10(-7), 10(-6), 10(-5), and 10(-4) M) and time course (day 2 vs. day 5) experiments were performed in an in vitro embryo adhesion assay composed of human polarized endometrial epithelial cells obtained from fertile patients and mouse embryos. MAIN OUTCOME MEASURE(S): Blastocyst formation rate and embryo adhesion rate. RESULTS: Monolayers of polarized endometrial epithelial cells expressed ERalpha at the mRNA level. The E(2) dose response of blastocysts with polarized endometrial epithelial cells (n = 235) demonstrated a progressive reduction in embryonic adhesion that was statistically significant at 10(-6) M. When polarized endometrial epithelial cells were treated alone with increasing doses of E(2) for 3 days and E(2) was then removed and blastocysts added (n = 410), embryonic adhesion was not significantly reduced, except at 10(-4) M. When 2-day mouse embryos (n = 609) were treated with increasing E(2) concentrations until day 5, the rate of blastocyst formation significantly decreased at a concentration >or= 10(-6) M, and embryonic adhesion decreased when blastocysts (n = 400) were obtained at a concentration >or= 10(-7) M. Time course experiments of embryos cultured for 2 days with polarized endometrial epithelial cells (n = 426) showed that the adhesion rate was higher at E(2) levels of 10(-7), 10(-6) and 10(-5) M compared with embryos cultured for 5 days (n = 495). CONCLUSION(S): High E(2) levels are deleterious to embryo adhesion in vitro, mainly because they have a direct toxic effect on the embryo that may occur at the cleavage stage.

Animals↗

PubMed2001

An analysis of spontaneous hatching in a human endometrial epithelial coculture system: is assisted hatching justified?

PURPOSE: To evaluate spontaneous embryo hatching in an endometrial epithelial coculture system, and compare it with cases where coculture was performed because of maternal age, previous repeated implantation failures, or both. To clarify in which cases assisted hatching would be appropriate. METHODS: Individual human embryos were cocultured on an endometrial epithelial cell monolayer until Day 6. RESULTS: Blastocyst hatching rate at Day 6, depending on maternal age, was 9.1% (age <37 years) and 3.4% (age > or = 37 years). However, blastocyst hatching rates depending on number of previous IVF failures were similar. CONCLUSIONS: Maternal age and previous implantation failures are factors affecting the ability of human embryos to reach the blastocyst stage in coculture. However, assisted hatching is not justified in these populations because of the absence of hatching rate differences between blastocysts obtained from these two groups and the control group.

Blastocyst↗

PubMed2001

Incidence of sperm chromosomal abnormalities in a risk population: relationship with sperm quality and ICSI outcome.

BACKGROUND: An increased incidence of chromosome abnormalities has been reported in sperm samples of many infertile men by fluorescence in-situ hybridization (FISH). METHODS: Sperm aneuploidy and diploidy rates for chromosomes 13, 18, 21, X and Y were evaluated in 63 patients with normal karyotypes using dual and triple-colour FISH techniques. Indications for sperm FISH analysis were: recurrent miscarriages of unknown aetiology (RM, n = 40), repeated implantation failure after intracytoplasmic sperm injection (ICSI) (IF, n = 19), previous Down's syndrome pregnancies (n = 3), and meiotic abnormalities (MA, n = 1). Nine healthy normozoospermic donors were also evaluated as a control group. RESULTS: A significant increase in the incidence of sex chromosome disomies was found in the RM, IF and MA groups. Oligoasthenoteratozoospermic patients (n = 21) showed significantly higher rates of diploidy and disomies for sex chromosomes and chromosomes 18 and 21 than normozoospermic patients (n = 14). Thirty-one patients with normal and seven with abnormal FISH results had undergone several ICSI treatments (108 and 23 cycles respectively). Couples with abnormal sperm FISH results showed decreased pregnancy and implantation rates and increased miscarriage rates. CONCLUSIONS: Patients with a clinical background of recurrent miscarriages of unknown aetiology or implantation failure after ICSI are at risk of showing sperm chromosomal abnormalities, the incidence of which is higher in oligoasthenoteratozoospermic patients.

Abortion, Habitual↗

PubMed2001

The effect of repeated controlled ovarian stimulation in donors.

BACKGROUND: The effect of repeated controlled ovarian stimulation in young, healthy women who consented to donate their oocytes was assessed through a retrospective study. METHODS AND RESULTS: Between March 1994 and February 2000, 284 donors consented to at least two controlled ovarian stimulation cycles, with four donors undergoing up to nine cycles. Through an intra-group analysis we studied the oocyte retrieval rate, controlled by the duration and doses of stimulation, as well as the interval between cycles, finding that the number of retrieved oocytes was maintained during repeated controlled ovarian stimulation cycles. The oocyte quality, assessed as fertilization, implantation and pregnancy rates, was similar through five repeated controlled ovarian stimulation cycles. The same result was obtained when the interval in days was analysed as a continuous variable or categorized in <90 and > or =90 days. CONCLUSIONS: The analysis of the data suggests that successive stimulation cycles do not impair ovarian response in terms of quantity and quality of the oocytes obtained in this group of women. Furthermore, the interval between cycles does not influence the result of the stimulations.

Adolescent↗

PubMed2001

Human ovarian steroid secretion in vivo: effects of GnRH agonist versus antagonist (cetrorelix).

BACKGROUND: In order to investigate whether gonadotrophin-releasing hormone (GnRH) antagonists exert a significant effect on steroid secretion in vivo compared with GnRH agonists, concentrations of sex steroid hormones (oestradiol, progesterone and testosterone) were studied in follicular fluid from women undergoing ovarian stimulation and treated with either GnRH agonist or antagonist. In addition, the correlation between follicular fluid steroid hormone concentrations and variables of follicular and oocyte development was evaluated. METHODS: Microparticle enzyme immunoassay and radioimmunoassays were used. RESULTS: The mean (SEM) follicular fluid oestradiol concentration was significantly lower in patients treated with GnRH antagonist than in those treated with GnRH agonist (542.0 +/- 76.9 versus 873.0 +/- 105.1 pg/ml, P = 0.02), which correlates with the mean serum oestradiol concentrations found in these two groups. No significant differences were found between groups in follicular fluid progesterone concentrations. Women undergoing GnRH antagonist treatment showed similar concentrations of follicular fluid testosterone compared with GnRH agonist-treated women (14.8 +/- 1.1 versus 13.3 +/- 2.7 ng/ml). The oestradiol:testosterone ratio was markedly reduced in women treated with GnRH antagonist (49.1 +/- 2.3 versus 60.1 +/- 4.4, P = 0.04). In contrast, no differences were found either in the progesterone:testosterone ratio, or in the oestradiol:progesterone ratio. CONCLUSIONS: GnRH antagonist therapy in women undergoing ovarian stimulation had a significant effect on ovarian follicular steroidogenesis.

Adult↗

PubMed2001

Endocrinological and ultrasonographic variations after immature oocyte retrieval in a natural cycle.

BACKGROUND: In-vitro oocyte maturation is an appealing alternative in reproductive medicine but the results obtained are still poor. The aim of our prospective and observational investigation was to study the hormonal modifications that immature follicular aspiration might induce in a natural cycle as well as the implications that these alterations may have in the endometrium. METHODS: Eleven patients (13 cycles) were included in our in-vitro oocyte maturation programme. Ovaries were scanned with transvaginal probes every day and follicular aspiration was performed when a follicle of 9 mm was visualized. Blood was also drawn for hormonal analysis. Endometrial thickness was recorded every day after oocyte retrieval. Two endometrial biopsies were taken on days 6 and 8 after oocyte retrieval. RESULTS: We observed a significant drop in serum oestradiol concentrations after immature oocyte retrieval previous to follicle dominance. Immediately after, rises in both FSH and LH were detected. Also, a new dominant follicle started to grow 3-4 days later. Steroid hormones secreted by this newly recruited follicle were significantly lower than in controls, inducing inadequate endometrial thickness. CONCLUSIONS: These studies show that exogenous hormonal administration might be necessary to achieve a correct endometrial growth when in-vitro oocyte maturation is employed in IVF.

Adult↗

PubMed2001

Human endometrial mucin MUC1 is up-regulated by progesterone and down-regulated in vitro by the human blastocyst.

Expression of MUC1 in endometrial epithelium has been suggested to create a barrier to embryo attachment that must be lifted at the time of implantation. In this study, we investigated the hormonal regulation of human endometrial MUC1 in hormone replacement therapy cycles and in the human blastocyst. We also analyzed the embryonic regulation of MUC1 in human endometrial epithelial cells (EECs) during the apposition and adhesion phases of human implantation using two different in vitro models. Our results indicate that endometrial MUC1 mRNA and immunoreactive protein increase in receptive endometrium compared to nonreceptive endometrium. Human blastocysts express MUC1, as demonstrated by reverse transcription-polymerase chain reaction and immunocytochemistry, localized at the trophectoderm. In vitro, MUC1 was present at the surface of primary cultures of human EEC, and presence of a human blastocyst (i.e., apposition phase) increases EEC MUC1 protein and mRNA compared to control EEC lacking embryos. Interestingly, when human blastocysts were allowed to attach to the EEC monolayer (i.e., adhesion phase), MUC1 was locally removed in a paracrine fashion on EEC at the implantation site. These results demonstrate a coordinated hormonal and embryonic regulation of EEC MUC1. Progesterone combined with estradiol priming induces an up-regulation of MUC1 at the receptive endometrium. During the apposition phase, presence of a human embryo increases EEC MUC1. However, at the adhesion phase, the embryo induces a paracrine cleavage of EEC MUC1 at the implantation site. These findings strongly suggest that MUC1 may act as an endometrial antiadhesive molecule that must be locally removed by the human blastocyst during the adhesion phase.

Adult↗

PubMed2001

Embryo effects in human implantation: embryonic regulation of endometrial molecules in human implantation.

Embryonic implantation requires coordinated development of the blastocyst and the maternal endometrium. Considerable advances have been made in the understanding of the cell biology of human embryo and maternal endometrium as separate entities. Nevertheless, communication between them and their reciprocal effects on each other constitute an exciting and as-yet unsolved problem in reproductive medicine. Cross-talk among the embryo, endometrium, and the corpus luteum are known to occur in ruminants and primates; more specifically, endometrial-embryonic interactions have been reported in rodents and primates. Here, we present updated information in humans on the embryonic regulation of endometrial epithelial molecules such as chemokines, adhesion molecules, antiadhesion molecules, and leptin during the apposition and adhesion phases of human implantation. Also the embryonic induction of apoptosis in endometrial epithelial cells as a mechanism for crossing the epithelial barrier will be described.

Apoptosis↗

PubMed2001

Endometrial quality in infertile women with endometriosis.

Several analyses in our infertility (IVF) and oocyte donation programs were carried out to gain clinical knowledge of the factors involved in the etiology of endometriosis-associated infertility. We first compared the IVF outcomes in women with tubal infertility and endometriosis. The results indicated that patients with endometriosis had a poorer IVF outcome in terms of reduced pregnancy rate per cycle, per transfer, and reduced implantation rate per embryo replaced. We then evaluated embryo development in vitro in women with and without endometriosis who underwent IVF and embryo replacement 72 hours after oocyte retrieval. We observed that compared to controls, patients with endometriosis had a significantly reduced number of blastomeres per embryo as well as an increased incidence of arrested embryos in vitro. In subsequent studies we compared fertility parameters in patients receiving donor oocytes. We noted that when donor oocytes came from patients without known endometriosis, embryo development and implantation rates were similar in patients with and without endometriosis. However, when the results of oocyte donation were classified according to the nature of the oocytes donated, patients who received embryos derived from oocytes from women with endometriotic ovaries showed a significantly reduced implantation rate compared to the controls. Taken together, these observations suggest that IVF in patients with endometriosis may be related to alterations within the oocyte, which, in turn, result in embryos of lower quality with a reduced ability to implant.

Endometriosis↗

PubMed2000

Intracytoplasmic sperm injection with cryopreserved testicular spermatozoa.

To assess if testicular sperm cryopreservation is a valid alternative to repetition of testicular sperm retrieval techniques, results of a cryopreservation technique in pills have been retrospectively analyzed. Enough motile spermatozoa for ICSI were obtained in 172 from 190 (90.5%) frozen-thawed testicular sperm samples. Overall, 249 couples underwent 390 ICSI cycles, 156 using fresh and 234 using cryopreserved testicular sperm. Mean two-pronuclear fertilization rates per cycle were not significantly different after ICSI with fresh (62.0%) or with cryopreserved (63.2%) spermatozoa. Mean embryo cleavage rate per cycle was higher in the fresh (90.6%) than in the cryopreserved (84.6%) group (P = 0.016). However, clinical pregnancy rates per cycle (28.2% with fresh vs 27.8% with cryopreserved), implantation rates (12.2% vs 13.1%) and ongoing pregnancy rates per cycle (22.4% vs 21.8%) were not significantly different. Cryopreservation of testicular spermatozoa is an effective technique that can be used both in obstructive and in non-obstructive azoospermia.

Adolescent↗

PubMed2000

Impact of stage III-IV endometriosis on recipients of sibling oocytes: matched case-control study.

OBJECTIVE: To evaluate the impact of severe endometriosis on IVF-ET outcome in women receiving oocytes from the-same donor. DESIGN: A matched case-control study. SETTING: Oocyte donation program at the Instituto Valenciano de Infertilidad. PATIENT(S): Fifty-eight recipients were included in a matched case-control study of IVF-ET in our oocyte donation program. Twenty-five patients were diagnosed by laparoscopy with stage III-IV endometriosis (group I), while the remaining 33 were free of the disease (group II). On the day of retrieval, oocytes from a single donor were donated to recipients from both groups. Some of the donors supplied oocytes for more than 2 patients. Recipients received steroid replacement therapy for endometrial preparation. INTERVENTION(S): Ovarian stimulation and oocyte retrieval in donors. Uterine embryo transfer (ET) in recipients after appropriate exogenous hormone replacement therapy (HRT). MAIN OUTCOME MEASURE(S): Pregnancy, implantation, miscarriage, and live birth rates. RESULT(S): The number of oocytes donated and fertilized, as well as the number of available and transferred embryos, was not statistically different between the two groups. Pregnancy, implantation, and miscarriage rates were not affected by stage III-IV endometriosis when compared with the control group. The live birth rate was 28.0% in the group with endometriosis and 27.2% in the control group. CONCLUSION(S): These results show that implantation is not affected by stage III-IV endometriosis. Given the contemporary methods of endometrial preparation for transfer of embryos derived from donor oocytes, any potential negative effect of severe endometriosis on the uterine environment is undetectable.

Abortion, Spontaneous↗

PubMed2000

The potential use of maturation in vitro of human oocytes in low responder patients.

PURPOSE: To assess whether maturation in vitro of human oocytes (MIVHO) could be an alternative treatment in low responders to ovarian stimulation for in vitro fertilization (IVF). METHODS: Prospective case-control study. Spontaneously ovulatory women who volunteered were included in our program of MIVHO at the Instituto Valenciano de Infertilidad. Rates of oocyte retrieval, in vitro maturation, fertilization, and development up to the blastocyst stage were studied. RESULTS: A significantly increased rate of oocyte retrieval was found when the pickup was performed before follicular selection. No differences were found when MIVHO was used in a low responder patient with an ovarian content of early antral follicles > 5 as compared to normal responders. CONCLUSIONS: MIVHO could be a successful choice in low responder patients with an acceptable number of early antral follicles. Oocyte retrieval should be performed before follicular selection in order to obtain more oocytes.

Adult↗

PubMed2000

The human blastocyst regulates endometrial epithelial apoptosis in embryonic adhesion.

The implanting blastocyst must appose and adhere to the endometrial epithelium and, subsequently, invade it. Locally regulated uterine epithelial apoptosis induced by the embryo is a crucial step of the epithelial invasion in rodents. To address the physiological relevance of this process in humans, we investigated the effect of single human blastocysts on the regulation of apoptosis in cultured human endometrial epithelial cells (hEEC) in both apposition and adhesion phases of implantation. Here, we report a co-ordinated embryonic regulation of hEEC apoptosis. In the apposition phase, the presence of a blastocyst rescues hEEC from the apoptotic pathway. However, when the human blastocyst adheres to the hEEC monolayer, it induces a paracrine apoptotic reaction. Fas ligand (Fas-L) was present at the embryonic trophoectoderm. Fas was localized at the apical cell surface of hEEC, and flow cytometry revealed that 60% of hEEC express Fas. Neutralizing adhesion assays revealed that the Fas/Fas-L death system may be an important mechanism to cross the epithelial barrier, which is crucial for embryonic adhesion, and the manipulation of this system could have potential clinical implications as an interceptive mechanism.

Apoptosis↗

PubMed2000

Embryo reduction of multifetal pregnancies following assisted reproduction treatment: a modification of the transvaginal ultrasound-guided technique.

First-trimester transvaginal embryo reduction is an effective alternative for the management of multifetal pregnancy in assisted reproduction. We have modified the transvaginal technique by performing an intracardiac embryo puncture until asystolia is verified, without the injection of any substances. Any aspiration of embryo tissues or amniotic fluid was avoided. A total of 149 multifetal pregnancies was reduced to twins (n = 134) or singletons (n = 15) at early gestational age (7.8 +/- 0.8 weeks). Eleven cases (7.3%) of miscarriage, two cases (1.3%) of chorioamnionitis, and 17 cases (11.4%) of transient spotting were recorded as postoperative complications. Vanishing of one embryo occurred in four cases (3.0%) of those reduced to twins. The baby take-home rate was 89.5% for twins and 80.0% for singletons. Pregnancy outcome was analysed and compared with a control group of women with non-reduced multiple pregnancies. The birth weight of singleton pregnancies after reduction was lower (2929 +/- 160 versus 3291 +/- 422 g; P < 0.02). These studies show that early transvaginal intracardiac embryo puncture is an effective and safe technique.

Adult↗

PubMed2000

High doses of gonadotrophins combined with stop versus non-stop protocol of GnRH analogue administration in low responder IVF patients: a prospective, randomized, controlled trial.

Recent evidence suggests that early cessation of gonadotrophin releasing hormone analogue (GnRHa) administration may offer some benefit to low responder patients undergoing IVF. A prospective, randomized controlled trial was designed to evaluate whether early cessation of GnRHa in an ovarian stimulation regimen is more beneficial than just increasing the doses of gonadotrophins. Seventy low responder patients (less than three mature follicles in a previous cycle) with normal basal follicle stimulating hormone concentrations and a previous cancelled IVF cycle were randomly allocated into two protocols: (i) non-stop protocol: long GnRHa suppression with high doses of gonadotrophins, and (ii) stop protocol, in which GnRHa administration is stopped with the onset of menses, while gonadotrophin doses remained similar to the non-stop protocol. A significantly higher number of mature oocytes were obtained in the study group (stop protocol) compared to the control group (non-stop protocol) (8.7 +/- 0.9 versus 6.2 +/- 0.7, P: = 0. 027). The stop protocol reduced the number of ampoules of gonadotrophins required (56.6 +/- 2.7 versus 68.0 +/- 3.5, P: = 0. 013). Both protocols resulted in a similar cancellation rate (2.7 versus 5.8%) (with no cycles cancelled due to ovulation), pregnancy rate (14.3 versus 18.7%), and implantation rate (12.1 versus 8.8%). The early cessation of GnRHa combined with high doses of gonadotrophins permitted the retrieval of a significantly higher number of oocytes.

Adult↗

PubMed2000

Increased adhesiveness in cultured endometrial-derived cells is related to the absence of moesin expression.

Human endometrial epithelial cells (EECs) are nonadhesive for embryos throughout most of the menstrual cycle. During the so-called implantation window, the apical plasma membrane of EECs acquire adhesive properties by undergoing a series of morphological and biochemical changes. The human endometrial-derived epithelial cell line, RL95-2, serves as an in vitro model for receptive uterine epithelium because of its high adhesiveness for trophoblast-derived cells. In contrast, the HEC-1-A cell line, which displays poor adhesive properties for trophoblast cells, is considered to be less receptive. The ezrin, radixin, and moesin protein family members, which are present underneath the apical plasma membrane, potentially act to link the cytoskeleton and membrane proteins. In the present study, we have further investigated the adhesive features in these two unrelated endometrial-derived cell lines using an established in vitro model for embryonic adhesion. We have also analyzed the protein pattern and mRNA expression of ezrin and moesin in RL95-2 cells versus HEC-1-A cells. The results demonstrate that RL95-2 cells were indeed more receptive (81% blastocyst adhesion) compared with HEC-1-A cells (46% blastocyst adhesion). An intermediate adhesion rate was found in primary EECs cultured on extracellular matrix gel, thus allowing a partial polarization of these cells (67% blastocyst adhesion). Furthermore, we found that moesin was absent from RL95-2 cells. In contrast, ezrin is expressed in both cell lines, yet it is reduced in adherent RL95-2 cells. Data are in agreement with the hypothesis that uterine receptivity requires down-regulation or absence of moesin, which is a less-polarized actin cytoskeleton.

Animals↗

PubMed2000

The pathophysiology of endometriosis-associated infertility: follicular environment and embryo quality.

Several retrospective analyses of IVF and oocyte donation programmes, performed to gain clinical knowledge of the factors implicated in the aetiology of endometriosis-associated infertility, have demonstrated that the quality of the embryo is affected in patients with endometriosis. To understand the mechanisms of this alteration, the endocrine, paracrine and autocrine conditions induced during folliculogenesis in women with and without endometriosis were investigated. The first approach was to study ovarian steroid secretion in women undergoing IVF. Progesterone concentrations in follicular fluid increased with the severity of the disease and an increase in progesterone accumulation in vitro was observed in basal and hCG-stimulated granulosa cell cultures. It is proposed that the pattern of progesterone secretion may be related to changes in the release of cytokines by ovarian and white blood cells. Hence, a second trial measured interleukin 1 (IL-1), IL-6 and vascular endothelial growth factor (VEGF) concentrations in serum, follicular fluid and granulosa cell cultures. IL-6 concentrations in serum were higher in the natural cycles of women with endometriosis than in women in the control group, and were modulated by ovarian stimulation, decreasing significantly in serum from stimulated cycles. In addition, IL-6 concentrations were higher in the follicular fluid of women with endometriosis than in those in the control group and IL-6 was released in higher amounts by granulosa luteal cells of patients with endometriosis. VEGF was accumulated in lower concentrations in the follicular fluid of patients with endometriosis. These observations indicate that infertility in patients with endometriosis may be related to alterations within the follicle which, in turn, result in oocytes and embryos of lower quality, as demonstrated in the IVF programme. In addition, these embryos have a reduced ability to implant, as observed in the oocyte donation model. These alterations may be induced by functional changes in the process of folliculogenesis that affect steroid synthesis, as well as by cytokine release by ovarian and blood cells.

Embryo Transfer↗

PubMed2000

Is there a place for preimplantation genetic diagnosis screening in recurrent miscarriage patients?

Chromosomal abnormalities are one of the factors known to interfere with normal embryo development; thus preimplantation genetic diagnosis (PGD) for chromosome anomalies may be a new tool for improving the pregnancy rate in selected groups of patients. Embryos from three groups of patients (control, aged and recurrent miscarriage patients) were screened by PGD using specific DNA probes for chromosomes 13, 16, 18, 21, 22, X and Y. The control and aged groups were included in the PGD study because the women carried sex-linked genetic disease. The frequencies of chromosome anomalies observed in older women (46.3%) and in recurrent miscarriage patients (53%) were significantly higher (P < 0.05) than the frequency in the control group (19.3%). After PGD screening and transfer of normal embryos, pregnancies were obtained in women who had undergone repeated abortions (approximate 25% pregnancy rate per transfer) but not in older women. On the basis of these data, it seems that PGD screening of embryos can help some women undergoing repeated abortions, as these techniques allow successful pregnancies to be obtained or, if no pregnancy can be obtained, the results may help the couple to decide whether to enter an embryo or gamete donation programme.

Abortion, Habitual↗