ABCC4 is a PGE2 efflux transporter in the ovarian follicle: A mediator of ovulation and a potential non-hormonal contraceptive target.

The role of prostaglandins (PGs) in the ovulatory process is known. However, the role of the ATP binding cassette subfamily C member 4 (ABCC4), transmembrane PG carrier protein, in ovulation remains unknown. We report herein that ABCC4 expression is significantly upregulated in preovulatory human granulosa cells (GCs). We found that PGE2 efflux in cultured human GCs is mediated by ABCC4 thus regulating its extracellular concentration. The ABCC4 inhibitor probenecid demonstrated effective blocking of ovulation and affects key ovulatory genes in female mice in vivo. We postulate that the reduction in PGE2 efflux caused by the inhibition of ABCC4 activity in GCs decreases the extracellular concentration of PGE2 and its ovulatory effect. Treatment of female mice with low dose of probenecid as well as with the PTGS inhibitor indomethacin or Meloxicam synergistically blocks ovulation. These results support the hypothesis that ABCC4 has an important role in ovulation and might be a potential target for non-hormonal contraception, especially in combination with PGE2 synthesis inhibitors. These findings may fill the gap in understanding the role of ABCC4 in PGE2 signaling, enhance the understanding of ovulatory disorders, and facilitate the treatment and control of fertility.

Comparison of effects of thawing entire donor sperm vial vs. partial thawing (shaving) on sperm quality.

PURPOSE: Partial thawing of a vial of cryopreserved sperm (shaving) is sometimes applied as a measure to preserve sperm for further use, particularly in cases of very restricted sperm quantity. However, mechanical violence may disrupt the sperm-wall and lead to impaired in-vitro fertilization (IVF) outcomes. MATERIAL AND METHODS: In a retrospective case-control study at a tertiary, university-affiliated medical center, we compared the IVF/intracytoplasmic sperm injection (ICSI) outcomes of patients who used donor sperm following partial thawing (shaving) of the vial of cryopreserved sperm (n = 99) to a control group consisting of patients for whom the vial of sperm was completely thawed before use (n = 99). RESULTS: While no differences were observed in the rates of oocyte fertilization, the mean number of top-quality embryos (TQE) was significantly lower in the shaving group than in the complete thawing group (1.33 ± 0.17 vs. 1.87 ± 0.17, p < 0.02). Experimental analysis of aliquots from the same donors revealed significantly reduced motility in sperm samples that were shaved vs. fully thawed (6.5 vs. 37.1%, p < 0.001). CONCLUSIONS: In cases in which available cryopreserved sperm samples are limited, shaving of the vial without thawing can be used but with caution and only when absolutely necessary. Further, large prospective studies are needed to better clarify whether there is post-thawing sperm damage and to compare IVF outcomes after these two thawing methods.

Outcome of immature oocytes collection of 119 cancer patients during ovarian tissue harvesting for fertility preservation.

PURPOSE: Few clinical options for fertility preservation are available to females with cancer, and data about clinical outcomes is limited. Potential supplementary approaches to fertility preservation include retrieval of immature oocytes followed by in vitro maturation (IVM) and storage. The aim of this study was to evaluate post-thawing outcomes of immature oocytes collected both by transvaginal aspiration and from excised ovarian tissue. METHODS: We conducted a retrospective cohort study of patients treated in a single tertiary center. We reviewed the records of 119 cancer patients who underwent ovarian tissue cryopreservation and immature oocyte harvesting for fertility preservation. All embryos and oocytes that were frozen and thawed were included in the study. Post-thawing outcomes were evaluated. RESULTS: Thirty-five stored embryos from eight patients were thawed. Twenty-nine embryos survived (82% survival rate) and were transferred. Six oocytes were thawed, two oocytes survived, and no oocytes were fertilized. Only one PCOS patient became pregnant, resulting in the normal delivery of a healthy baby. CONCLUSIONS: Although a relatively high number of mature oocytes and embryos can be stored with the combined procedure, the limited rate of pregnancies represents a poor reproductive outcome. Therefore, this approach should be reserved for special groups with limited options.

The 'immunologic theory' of preeclampsia revisited: a lesson from donor oocyte gestations.

OBJECTIVE: To determine the prevalence of placental complications in patients conceived through donor versus autologous oocytes. STUDY DESIGN: A retrospective cohort study including 2 groups of patients who conceived through in vitro fertilization using: (1) donor oocyte (n = 139) and (2) autologous oocyte (n = 126). Only singleton gestations were included. The rate of placental complications including preeclampsia, gestational hypertension, and intrauterine growth restriction was compared between these 2 groups. RESULTS: The women who conceived using donor oocytes were older compared with women who conceived using autologous oocytes (median maternal age 45 vs 41, P < .01). The rate of hypertensive diseases of pregnancy including gestational hypertension and preeclampsia was significantly higher in ovum donor recipients compared with women conceived with autologous oocytes (25% vs 10%, P < .01). Similarly, the rate of intrauterine growth restriction was also higher among patients conceived through oocyte donation although it did not reach statistical significance (9.3% vs 4%, P = .08). When maternal age was restricted to ≤45 years, the rate of hypertensive diseases of pregnancy remained significantly higher among ovum donor compared with autologous oocyte recipients (22% vs 10%, P = .02). Adjustment for maternal age, gravidity, parity, and chronic hypertension revealed that oocyte donation was independently associated with higher rate of hypertensive diseases of pregnancy (P = .01). CONCLUSION: Patients conceived through oocyte donation have an increased risk for placental complications of pregnancy. These findings support the 'immunologic theory' suggesting that immunologic intolerance between the mother and the fetus may play an important role in the pathogenesis of preeclampsia.

Comparison between two protocols for thawed embryo transfer: natural cycle versus exogenous hormone replacement.

INTRODUCTION: There are two most popular protocols for Frozen Embryo Transfer: the natural and the E2&P4 replacement cycles. There is still a controversy whether one is superior over the other. PURPOSE: To compare the outcome in patient groups undergoing FET following these protocols. METHODS: About 1235 FET cycles were retrospectively analyzed during a period of 12 years. In 798 cycles (group A), the natural cycle protocol was used, and in 437 cycles (group B), the exogenous E2&P4 administration protocol was used. RESULTS: The average patient age was 32.11 ± 0.27 years in group A and 32.94 ± 0.19 years in group B (p<0.05). The endometrial thickness was 9.54 ± 0.11 mm and 8.95 ± 0.13 mm in groups A and B, respectively (p<0.001). The peak serum E2 level was 162.51 ± 8.97 pg/mL and 250.78 ± 33.67 pg/mL in groups A and B, respectively (p<0.001). The implantation, clinical pregnancy, and ongoing pregnancy rates in groups A and B were 6.47%, 12.91%, and 10.4% versus 4.26%, 8.47%, and 5.95%, respectively (p<0.05). CONCLUSIONS: Natural endometrial preparation yields better outcome in compare with exogenous E2&P4 in FET cycles with higher endometrial thickness, implantation, and clinical pregnancy rates.

Differential expression of poliovirus receptor, regulator of G-protein signaling 11 and erythrocyte protein band 4.1-like 3 in human granulosa cells during follicular growth and maturation.

Poliovirus receptor (PVR), regulator of G-protein signaling-11 (RGS11), and erythrocyte protein band-4.1-like 3 (EPB41L3) have been proposed to function in follicular maturation in mouse models. We have examined their expression in human mural (mGCs) and cumulus granulosa cells (CCs). Expression of PVR and RGS11 in mGCs decreased in medium-sized follicles compared to small follicles of IVM cycles and increased again in large follicles. Luteinization caused decreased expression of both PVR and RGS11. In vitro incubation of mGCs with progesterone-rich conditioned media decreased expression of RGS11 without affecting PVR levels. Inhibition of progesterone signaling enhanced expression of both RGS11 and PVR. Expression in CCs was examined by means of global transcriptome sequencing analysis RGS11 and EPB41L3 increased in CCs during follicular maturation while PVR levels did not change. In conclusion, during human follicular maturation there are significant changes in expression of PVR, RGS11 and EPB41L3, possibly regulated by progesterone.

Progesterone antagonist, RU486, represses LHCGR expression and LH/hCG signaling in cultured luteinized human mural granulosa cells.

Progesterone, the main steroid synthesized by the corpus luteum (CL), prepares the uterus for implantation, maintains the CL survival, and induces progesterone auto-secretion. However, the molecular mechanisms involving the progesterone auto-secretion pathways at the luteal phase are not fully understood, especially in humans. We aim to study the molecular mechanism of the progesterone pathway in human granulosa cells. Our model system consists of luteinized human-mural-granulosa-cells (hmGCs) obtained from follicles aspirated during in vitro fertilization (IVF) procedures. hmGCs were seeded in culture and were subjected to different hormonal treatments. mRNA levels were analyzed by quantitative real-time PCR (qRT-PCR). Progesterone levels were measured by enzyme immunoassay (EIA). We show that exposure of luteinized hmGCs to the progesterone receptor antagonist, RU486 (mifepristone), resulted in inhibition of LHCGR, LH/hCG target genes and progesterone secretion. Exposure of hmGCs to medium that was incubated with hmGCs for 4 d - conditioned medium (CM), which contain 150 ± 7.5 nM progesterone, resulted in induction of LHCGR and LH/hCG target genes, which was blocked by RU486. In addition, RU486 inhibited some of the progesterone biosynthesis pathway genes. Our results revealed a novel mechanism of the progesterone antagonist pathway in the luteal granulosa cells and emphasis the fundamental role of progesterone in the early luteal phase.

Cryopreservation of day 2-3 embryos by vitrification yields better outcome than slow freezing.

OBJECTIVE: To compare the outcome of vitrification versus slow freezing cryopreservation for cleavage stage day 2-3 embryos. DESIGN: A retrospective observational study. SETTING: All thawed embryos assisted reproduction cycles between January 2010 and December 2012 at a single IVF laboratory of a Tertiary Medical Center. PATIENTS: Five hundred and thirty-nine cycles of day 2-3 thawed embryos. INTERVENTIONS: In 327 of the thawed cycles, the embryos were vitrified and in 212 of the cycles the embryos were derived from slow freezing embryos. MAIN OUTCOMES MEASURE: Embryo survival rate, blastomere surviving rate and pregnancy rate. RESULTS: Embryo survival rate was significantly higher after vitrification compared with slow freezing (81.6%, 647/793 versus 70.0%, 393/562 embryos, p < 0.0001). The clinical pregnancy rate per ET was significantly higher following vitrification compared to slow freezing, 20.0%, 63/314 versus 11.9%, 23/193, respectively (p = 0.02). CONCLUSIONS: Vitrification of day 2-3 cleavage stage embryos yields better cycle outcome in all the parameters compared to slow freezing.

GnRH agonist early follicular challenge test as a predictor of ovarian response in antagonist cycles for fertility preservation.

The aim of our study was to evaluate if the response to follicular GnRH agonist (GnRHa) trigger be used to predict intracycle ovarian response in GnRH antagonist cycles among women undergoing fertility preservation IVF. We conducted a prospective study of 146 GnRH antagonist oocyte pickup (OPU) cycles to evaluate GnRHa stimulation test (GAST). On day 2 of the cycle, basal E2 were measured, followed by injection of 0.2 mg GnRHa as part of the initial ovarian stimulation. 12 h later blood sampling was repeated (GAST E3). E2 response was used as test parameter. The major outcome was the number of mature cryopreserved oocytes. We found a linear correlation between both GAST E3 level and GAST E3/E2 ratio and number of M2 oocytes. ROC curve analysis of GAST E3, GAST E3/E2 ratio, AFC and day 3 FSH for > 15 M2 and < 5 M2 oocytes was calculated. For GAST E3 levels obtaining < 5 M2 oocytes, an AUC value of 0.79 was found. For GAST E3 levels obtaining > 15 M2 oocytes, AUC value of 0.8. Patients with GAST E3 ≤ 384 pmol/l has 58.6% risk to obtain < 5 oocytes. Patients younger than 35 with GAST E3 > 708 pmol/l have 66% chance for freezing > 15 oocytes. The response to single GnRHa administration during GnRH antagonist cycle can be used as biomarker of ovarian reserve. This simple, widely available marker, which reflect the estradiol response of small follicles, might predict the response of the specific cycle, and can potentially be used to adjust the treatment dose.Trial registration number: 0304-20-ASF.

Anti-Müllerian hormone (AMH) downregulation in late antral stages is impaired in PCOS patients. A study in normo-ovulatory and PCOS patients undergoing in vitro maturation (IVM) treatments.

PURPOSE: To prospectively study the AMH expression and secretion pattern in mural granulosa cells (GCs) and follicular fluid (FF) from small follicles and medium follicles that were collected from normo-ovulatory (NO) and polycystic ovary syndrome (PCOS) patients undergoing in vitro maturation (IVM) treatments. METHODS: FF AMH levels and mRNA expression of mural GCs were measured in small (≤ 10 mm) and medium size follicles (11-15 mm) obtained from IVM treatments and large size follicles (≥ 16 mm) obtained from in vitro fertilization treatments. RESULTS: First, we show that AMH expression and protein level in the FF of NO patients were significantly higher in the small size follicles than in the medium and large size follicles (p < 0.003). We could not demonstrate these differences in PCOS patients. Second, we found significantly higher levels of AMH protein and mRNA in the large and medium (but not small) size follicles of PCOS patients compared to follicles from NO patients (p < 0.02). Finally, we observed a positive correlation between FF AMH of small and medium size follicles from NO patients and serum AMH (p < 0.03 and p < 0.0002, respectively). CONCLUSIONS: Our data demonstrate a pathological dysregulation of AMH expression and secretion in follicles from PCOS patients and emphasize the association between the physiological downregulation of AMH and follicular antral health.

What is the optimal threshold of serum Anti-Müllerian hormone (AMH) necessary for IVM treatments?

PURPOSE: To assesse circulating levels of Anti-Müllerian hormone (AMH) as a predictor of oocyte number and their potential to mature in vitro in both normo-ovulatory (NO) women and in women with Polycystic Ovary Syndrome (PCOS) undergoing in vitro maturation (IVM) treatments. METHODS: We prospectively studied NO women and women diagnosed with PCOS, (age range 21-39 years) underwent IVM treatments at our center. Serum AMH levels were quantified before each cycle and correlated to oocytes number, maturation and fertilization during in vitro maturation. RESULTS: 104 NO and 30 PCOS IVM cycles were followed with retrieval of a total of 672 and 491 oocytes, respectively. In NO women, the serum AMH level positively correlated with the number of oocytes retrieved, (R = 0.6; P <0.0001) the number of M2 oocytes at 24 and 48 h (R = 0.4; P <0.01; R = 0.26 p < 0.007, respectively) and with the total number of M2 oocytes (R = 0.47; P < 0.0001). In the PCOS group, the serum AMH level positively correlated only with the number of oocytes retrieved (R = 0.43; P <0.03). Receiver operating characteristic (ROC) analyses showed that a cutoff AMH level of 1.56 (ng/ml) could identify patients with 5 or more oocytes at OPU with a sensitivity of 83 % and a specificity of 75 %. An AMH level of 1.63 (ng/ml) was the threshold for 5 or more matured oocytes (sensitivity = 81 %, specificity = 53 %). CONCLUSIONS: Serum AMH may be used as a marker to identify candidates for IVM treatment in both NO and PCOS women.

Previous abortion is a positive predictor for ongoing pregnancy in the next cycle in women with repeated IVF failures.

Early pregnancy loss is common among women treated with assisted reproduction treatment, but whether it is a prognostic factor for success in subsequent IVF cycles is not well established. The aim of this study was to determine whether a biochemical pregnancy (BP) or spontaneous abortion (SA) affects the pregnancy rates in the following cycle. A retrospective study of 2687 women undergoing 6678 cycles between January 1998 and March 2010 was performed. Ongoing pregnancy rate (PR) per cycle was compared between patients with a pregnancy loss versus a negative ß-HCG in their previous cycles. Multivariate analysis of factors affecting ongoing pregnancy rate was performed. BP and/or SA in the first three cycles did not significantly alter the chances to conceive (16.9% patients with BP and/or SA in the previous cycle versus 16.5% patients with no previous pregnancy). From cycle 4 onwards, the presence of a previous abortion (either BP or SA) was associated with better ongoing PR (23.0% versus 11.2%, P<0.001). In conclusion, BP and/or SA in a previous cycle appears to be a positive marker for success in subsequent cycles in patients with repeated IVF failures. These results should be further investigated in this challenging group of patients.

Anti-Müllerian hormone is highly expressed and secreted from cumulus granulosa cells of stimulated preovulatory immature and atretic oocytes.

This study investigated anti-Müllerian hormone (AMH) expression and secretion from cumulus granulosa cells (GC) and steroidogenesis in follicular fluids (FF) with relation to oocyte maturational stages and fertilization capacity in large preovulatory follicles. This prospective study included 53 ovulatory women undergoing intracytoplasmic sperm injection. FF and cumulus GC from 140 large preovulatory follicles were individually obtained during oocyte retrieval. Main outcome measures were oocyte maturation, fertilization and embryo quality. FF were assayed for AMH, progesterone, 17ß-oestradiol and testosterone. Cumulus GC were assayed for AMH mRNA expression. AMH mRNA expression and secretion in cumulus GC in preovulatory follicles containing germinal-vesicle (GV) and metaphase-I (MI) oocytes were significantly higher than follicles containing MII oocytes (P<0.01 and P<0.0001, respectively). In addition, FF AMH concentrations from atretic oocytes were significantly higher than from MII oocytes. No correlation was found between AMH expression and secretion to fertilization or embryo quality. FF of MI and GV oocytes had higher concentrations of testosterone and lower progesterone/oestradiol ratios than MII oocytes, and FF of atretic oocytes contained higher testosterone concentrations than FF of MII oocytes. AMH is highly expressed in and secreted from cumulus GC of preovulatory follicles containing premature and atretic oocytes. Anti-Müllerian hormone (AMH) is produced in the female exclusively by granulosa cells. AMH has recently been shown to be one of the most important markers of ovarian reserve and it is highly associated with ovarian follicular development. This study investigates AMH expression and secretion from cumulus granulosa cells (GC) and steroidogenesis in the follicular fluids (FF) with relation to oocyte maturational stages, and fertilization capacity in large preovulatory follicles. We conducted a prospective study with 53 ovulatory women undergoing intracytoplasmic sperm injection. FF and cumulus GC from 140 large preovulatory follicles were individually obtained during oocyte retrieval. The main outcome measures were oocyte maturation, fertilization and embryo quality. FF were assayed for AMH, progesterone, 17ß-oestradiol and testosterone. Cumulus GC were assayed for AMH mRNA expression. AMH mRNA expression in cumulus GC and AMH concentrations in FF of preovulatory follicles containing premature oocytes (germinal vesicle (GV) and metaphase I (MI)) were significantly higher than preovulatory follicles containing mature oocytes (MII oocytes). In addition, FF AMH concentrations of atretic oocytes were significantly higher than FF AMH of MII oocytes. No correlation was found between AMH expression and secretion for fertilization or embryo quality. FF of preovulatory MI and GV oocytes had higher levels of testosterone and lower progesterone/oestradiol ratios than MII oocytes, and FF of atretic oocytes contained higher testosterone levels than FF of MII oocytes. This study shows that AMH is highly expressed in and secreted from cumulus GC of preovulatory follicles containing premature and atretic oocytes.

Does local injury to the endometrium before IVF cycle really affect treatment outcome? Results of a randomized placebo controlled trial.

AIM: To evaluate the effect of local injury to the endometrium during spontaneous menstrual cycles before in vitro fertilization (IVF) treatment on implantation and pregnancy rates in women with recurrent implantation failure (RIF). METHODS: In a prospective randomized controlled trial (RCT), a total of 36 patients, with RIF undergoing IVF, were randomized to two groups. In 18 patients, endometrial biopsies were performed using a pipelle curette on days 9-12 and 21-24 of the menstrual cycle preceding IVF treatment. In 18 control patients, a cervical pipelle was performed. RESULTS: The implantation rate (2.08% versus 11.11%; p = 0.1), clinical (0% versus 31.25%; p < 0.05) and live births rates (0% versus 25%; p = 0.1) were lower in the experimental group compared with controls. CONCLUSION: Our RCT did not find any benefit from local injury to the endometrium in women with a high number of RIFs. Further studies are warranted to better define the target population of patients who may benefit from this procedure.

Coronavirus disease 2019 vaccination and infertility treatment outcomes.

OBJECTIVE: To assess the influence of coronavirus disease 2019 (COVID-19) messenger ribonucleic acid vaccine on ovarian response and in vitro fertilization (IVF) treatment outcomes. DESIGN: A retrospective cohort study. SETTING: A tertiary university-affiliated medical center and a private medical center. PATIENT(S): The study included a total of 400 patients, 200 vaccinated women and 200 age-matched unvaccinated women, who underwent IVF in January-April 2021. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The mean number of oocytes retrieved and clinical pregnancy rates in vaccinated vs. unvaccinated patients. RESULT(S): A total of 200 patients underwent oocyte retrieval 14-68 days after receiving COVID-19 vaccination. No difference was found in the mean number of oocytes retrieved per cycle (10.63 vs. 10.72) between vaccinated and unvaccinated patients. Among 128 vaccinated and 133 unvaccinated patients who underwent fresh embryos transfers, no difference was demonstrated in the clinical pregnancy rates (32.8% vs. 33.1%), with 42 and 44 clinical pregnancies, respectively. The fertilization rates and mean number of cryopreserved embryos were similar between the 2 groups in freeze-all cycles (55.43% vs. 54.29% and 3.59 vs. 3.28, respectively). Among vaccinated and unvaccinated patients who underwent fresh embryo transfers, no difference was noted in the fertilization rate (64.81% vs. 61.98%) and transferred embryos' quality. Regression models applied demonstrated no effect of the vaccine on oocyte yields and pregnancy rates. CONCLUSION(S): The COVID-19 messenger ribonucleic acid vaccine did not affect the ovarian response or pregnancy rates in IVF treatment. Women should be vaccinated for COVID-19 before attempting to conceive via IVF treatments, given the higher risk of severe illness in pregnant women.

Molecular characterization of the human ovulatory cascade-lesson from the IVF/IVM model.

AIMS: Ovarian follicular development and ovulation in mammals is a complex and highly regulated process. Most advances in the understanding of the ovulatory process have come from animal models. However, translational research in humans is of crucial importance for improving fertility treatment and control. METHODS: IVM/IVF procedures allow us to obtain follicular fluid and granulosa cells (GC) from follicles in different developmental stages with and without hCG priming. RESULTS: Using the cells and fluids obtained in IVM/IVF procedures allowed us to characterize human ovulatory gene expression during antral folliculogenesis and ovulation, examine gene expression in luteinized and non-luteinized GC in vivo and in vitro and to use cumulus GC genes as biomarkers for oocyte and embryo maturity and competence. CONCLUSION: Biological material obtained during IVM/IVF procedures is an important tool to study the human ovulatory cascade and can serve to improve IVM techniques and fertility treatment and control.

HAS2-AS1 is a novel LH/hCG target gene regulating HAS2 expression and enhancing cumulus cells migration.

BACKGROUND: The cumulus expansion process is one of the LH mediated ovulatory processes. Hyaluronan synthase 2 (HAS2) regulates the synthesis of hyaluronic acid, the main component of the cumulus expansion process. Recently, the lncRNA HAS2 antisense RNA 1 (HAS2-AS1) was identified in our global transcriptome RNA-sequencing of novel ovulation associated genes. The role of HAS2-AS1 in HAS2 regulation w.as studied previously with contradictive results in different models but not in the ovary. Taken together the induction of HAS2-AS1 and the important role of HAS2 in the cumulus expansion process, we hypothesize that HAS2-AS1 regulate HAS2 expression and function in the ovary. Therefore we undertook to study the expression, regulation, and possible functional role of HAS2-AS1 in the human ovary. RESULTS: HAS2-AS1, located within the HAS2 gene that was highly regulated in our library. We found that HAS2-AS1 express mainly in cumulus cells (CCs). Furthermore, HAS2-AS1 showed low expression in immature CCs and a significant increase expression in mature CCs. Functional studies reveal that inhibition of HAS2-AS1 by siRNA caused decrease expression of HAS2. Furthermore, inhibition of HAS2-AS1 by siRNA results in decrease migration of granulosa cells. CONCLUSIONS: Our results suggest that HAS2-AS1 is an LH/hCG target gene that plays a positive role in HAS2 expression and thus might play a role in regulating cumulus expansion and migration.

The prostaglandin transporter (PGT) as a potential mediator of ovulation.

Prostaglandins (PGs) play an important role in the ovulatory process. However, the role of the PG transporter (PGT) in this context remains unknown. We report that the expression of PGT, a transmembrane PG carrier protein, is markedly up-regulated in preovulatory human granulosa cells (GCs). Treatment with human chorionic gonadotropin (hCG), an ovulatory trigger, significantly increases the expression of PGT mRNA and protein in human GCs both in vivo and in vitro. The hCG-induced increase in the expression of PGT in cultured human GCs is mediated via protein kinase A and protein kinase C by way of the extracellular signal-regulated kinase pathway. PGT in cultured human GCs mediates the uptake of PGE2, thereby regulating its extracellular concentration. In vivo treatment of mice with PGT inhibitors effectively blocks ovulation and markedly attenuates the expression of key ovulatory genes. We hypothesize that the inhibition of PGT activity in GCs increases the extracellular concentration of PGE2, the ability of which to exert its ovulatory effect is compromised by desensitization of its cognate receptors. Together, these findings support the idea that PGT is an important mediator of ovulation and that its inhibitors may be viewed as potential candidates for nonhormonal contraception. These findings may also fill the gap in the understanding of PGT signaling, enhance the understanding of ovulatory disorders, and facilitate the treatment of infertility or subfertility in women by using nonsteroidal PG-based therapeutic approaches.

Met-HGF/SF signal transduction induces mimp, a novel mitochondrial carrier homologue, which leads to mitochondrial depolarization.

Met-hepatocyte growth factor/scatter factor (HGF/SF) signaling plays an important role in epithelial tissue morphogenesis, lumen formation, and tumorigenicity. We have recently demonstrated that HGF/SF also alters the metabolic activity of cells by enhancing both the glycolytic and oxidative phosphorylation pathways of energy production. Using differential display polymerase chain reaction, we cloned a novel gene, designated mimp (Met-Induced Mitochondrial Protein), which is upregulated in NIH-3T3 cells cotransfected with both HGF/SF and Met (HMH cells). Northern and Western blot analyses showed that mimp is induced in several Met-expressing cell lines following treatment with HGF/SF. Mimp encodes a 33-kDa protein that shows sequence homology to the family of mitochondrial carrier proteins (MCPs). Murine Mimp (mMimp) is expressed in a wide variety of tissues, exhibiting an expression pattern similar to Met. Predominant expression is seen in liver, kidney, heart, skeletal muscle, and testis. Using immunostaining for HA-tagged mMimp and a GFP-mMimp chimeric protein as well as subcellular fractionation, we determined that Mimp is primarily localized to the mitochondria. Ectopic expression of mMimp in the Met-responsive adenocarcinoma cell line, DA3, reduced the mitochondrial membrane potential (uncoupling activity). The extent of the mitochondrial depolarization positively correlated with the level of Mimp expression. Our results demonstrate that Mimp is a novel mitochondrial carrier homologue upregulated by Met-HGF/SF signal transduction, which leads to mitochondrial depolarization, and suggest novel links among tyrosine kinase signaling, mitochondrial function, and cellular bioenergetics.

Is the modified natural in vitro fertilization cycle justified in patients with "genuine" poor response to controlled ovarian hyperstimulation?

OBJECTIVE: To examine whether patients with poor ovarian response (POR) during conventional IVF/intracytoplasmic sperm injection (ICSI) treatment cycle may benefit from a modified natural cycle (MNC)-IVF. DESIGN: Cohort historic study. SETTING: Tertiary, university-affiliated medical center. PATIENT(S): One hundred eleven patients with POR, defined according to the Bologna criteria, who underwent a subsequent MNC-IVF within 3 months of the previous failed conventional IVF/ICSI cycle. The elimination of bias in this selection, for the purposes of this study, was achieved by including only a subgroup of "genuine" poor responder patients, those who yielded up to three oocytes after controlled ovarian hyperstimulation (COH) with a minimal gonadotropin daily dose of 300 IU. INTERVENTION(S): Modified natural cycle IVF protocol with GnRH antagonist (GnRH-a) supplementation. Gonadotropin-releasing hormone antagonist treatment was started when a follicle of 13 mm was present. Two to three ampules of hMG were coadministered daily during the GnRH-a treatment. MAIN OUTCOME MEASURE(S): Live birth rate, pregnancy rate (PR), number of oocytes retrieved, and number of embryos transferred. RESULT(S): Live birth rate in "genuine" poor ovarian responders was <1%. Furthermore, in the subgroup of patients with POR who underwent a previous conventional IVF/ICSI cycle with a yield of only one oocyte, no pregnancies were achieved during the MNC-IVF cycle. CONCLUSION(S): Modified natural cycle-IVF is of no benefit for genuine poor ovarian responders and the option of egg donation should be seriously considered for this population.