Dalit Ben-Yosef

PGD-derived human embryonic stem cell lines as a powerful tool for the study of human genetic disorders.

Human embryonic stem (ES) cells are derived from the inner cell mass (ICM) of blastocyst embryos. They are established from spare embryos that have been obtained by in vitro fertilization (IVF) and donated for research purposes. The ICM-derived cell lines have two unique properties, they can be propagated indefinitely in culture and have the potential to develop into practically any cell type in vitro and in vivo. Human embryonic stem (hES) cells carrying specific mutations can be used as a valuable tool for studying genetic disorders in human. One favorable approach to obtain such mutant ES cell lines is their derivation from affected preimplantation genetic diagnosed (PGD) embryos. This review focuses on the importance of deriving human ES cell lines from genetically abnormal embryos, especially in cases where no good cellular and/or animal models exist.

Ovarian stimulation and emergency in vitro fertilization for fertility preservation in cancer patients

OBJECTIVE To evaluate the outcome of ovarian stimulation and in vitro fertilization (IVF) in women undergoing fertility preservation prior to chemotherapy compared with healthy patients with infertility due to tubal factor. STUDY DESIGN Case control, retrospective study in an academic IVF unit. The study participants were 21 cancer patients and 1 patient with focal proliferative glomerulosclerosis, undergoing emergency IVF or intracytoplasmic sperm injection (ICSI; Group A) and 22 patients undergoing IVF for tubal factor (Group B). All patients underwent controlled ovarian stimulation, ovum pick-up, and embryo freezing or transfer. The outcome measures included: dose of gonadotropins, mean estradiol and progesterone levels, length of stimulation, number of retrieved oocytes, number of 2 pronuclei zygotes, fertilization rate, and clinical pregnancy rate. Students t-test was used for assessment of group comparisons. RESULTS Patients in Group A (mean age 32.8+/-5.7 years) underwent 22 emergency IVF cycles for fertility preservation prior to chemotherapy. The mean number of days until human chorionic gonadotropin administration was 10.4+/-4.8. Eleven cycles involved normal insemination while nine involved ICSI. In one cycle three arrested immature oocytes were retrieved, and in one cycle no oocytes were retrieved. Donor sperm was used in 9 cycles. Tamoxifen was part of the treatment protocol in 6 IVF cycles of breast cancer patients. The mean age of the women in Group B was 34+/-4.2 years. There were no significant differences in any of the main outcome measures between the two groups. Thawed embryos were transferred in four cancer patients: two patients had colon cancer, one had breast cancer and one had pseudomyxoma peritonei. Two of these four women conceived and gave birth to healthy newborns. CONCLUSIONS Emergency IVF is a promising approach for preserving fertility in cancer patients. Current treatment protocols offer a minimal time delay until chemotherapy is commenced, and the ovarian stimulation outcomes are comparable to those of women with tubal factor.

Human Embryonic Stem Cells as a Powerful Tool for Studying Human Embryogenesis

Human embryonic stem cells (HESC) are pluripotent stem cell lines derived from the inner cell mass (ICM) of human blastocyst-stage embryos. They are characterized by their unlimited capacity to self-renew in culture. In addition, they have a broad developmental potential, as demonstrated by their ability to form practically any cell type in vivo and in vitro. These two features have made HESC extremely important in basic and applied research. In addition, they may serve as a powerful tool for studying human development. HESC can recapitulate embryogenesis by expressing developmentally regulated genes and by activating molecular pathways as they occur in vivo. Moreover, they can be used to analyze the effect of specific mutations on particular developmental events and may enable us to identify critical factors that play a role in the processes of cell commitment, differentiation, and adult cell reprogramming. Thus, modeling human embryogenesis by the use of HESC may allow new insights into developmental processes, which would otherwise be inaccessible for research.

High Levels of Anticardiolipin Antibodies in Patients with Abnormal Embryo Morphology Who Attended an In Vitro Fertilization Program

PROBLEM: Recently, it has been suggested that anticardiolipin antibodies (ACAs) may serve as possible markers for reproductive failure. The association between ACAs and embryo morphology in patients undergoing in vitro fertilization (IVF) was investigated.

Prospective Randomized Comparison of Two Embryo Culture Systems: P1 Medium by Irvine Scientific and the Cook IVF Medium

AbstractPurpose: To compare the efficacy of two commercially available in vitro fertilization (IVF) and embryo culture media systems: the glucose-free P1 Medium supplemented with 20% synthetic serum substitute (SSS) (Irvine Scientific), and the Cook IVF Medium (Cook, Australia). Methods: A prospective randomized study. Medical center-based IVF Unit affiliated to the Faculty of Medicine of Tel Aviv University. IVF patients were randomly assigned to either P1 Medium supplemented with 20% SSS (182 patients, 196 cycles) or Cook Medium (167 patients, 179 cycles). Results: Fertilization rates were similar with both media (52.3 ± 26.1 and 53.8 ± 27.6, respectively). Likewise, no difference was found in morphological characteristics and grading of cultured embryos. However, a significantly higher proportion of the embryos incubated in the P1 Medium reached the four-cell stage on day 2 or the 6-cell stage on day 3 postfertilization, compared to those incubated in Cook Medium (54.3% vs. 41.9%, p<0.0001). Clinical pregnancy and delivery rates were improved when oocytes and embryos were cultured in P1 Medium. Finally, Implantation rate was significantly higher in the P1 Medium Group (9.9% vs. 6%, respectively). Conclusions: Our results suggest that the P1 Medium may be associated with a higher embryo cleavage rate and improved implantation rates compared to the Cook IVF Medium.

Effects of laser polar-body biopsy on embryo quality

OBJECTIVE To evaluate the effect of laser polar-body biopsy (PBB) for preimplantation genetic diagnosis on embryo quality. STUDY DESIGN Retrospective case-control analysis. The quality of 145 embryos after PBB was compared to 276 embryos of the same group of women without biopsy. SETTING University-based tertiary-care medical center. PATIENT(S) Women with inherited genetics disease. INTERVENTION(S) Laser PBB of IVF embryos for genetic diagnosis. MAIN OUTCOME MEASURE(S) The study and control embryos were compared for fertilization rate, pronuclear grading, and cleavage-stage parameters on days 1, 2, and 3 after oocyte retrieval. RESULT(S) The study embryos demonstrated higher rates of cleavage arrest (3.6% vs. 0.7%), higher rate of significant fragmentation on day 2 (9.5% vs. 3.0%), and lower rate of good cleavage embryos on day 2 (69.1% vs. 78.4%) compared with control embryos. On day 3, the study embryos had lower cleavage rates (six or more blastomeres; 56.5% vs. 74.5%), higher fragmentation (11.7% vs. 3.9%), higher rate of embryos presenting inferior cleavage pattern (57.2% vs. 38.5%), and lower mean blastomere number (5.8 ± 2.1 vs. 6.6 ± 1.9) compared with control embryos. CONCLUSION(S) Polar-body biopsy may have a negative effect on embryo quality.

The effect of CGG repeat number on ovarian response among fragile X premutation carriers undergoing preimplantation genetic diagnosis

OBJECTIVE To assess ovarian response among carriers of FMR1 premutation who undergo preimplantation genetic diagnosis (PGD). DESIGN Retrospective study. SETTING Academic IVF unit. PATIENT(S) Of 18 carriers of FMR1 premutation referred to PGD, eight had <100 CGG repeats and ten had >or=100 CGG repeats. INTERVENTION(S) Controlled ovarian stimulation (COH) and PGD. MAIN OUTCOME MEASURE(S) Correlation between the number of CGG repeats and the level of E2 at day of hCG administration, number of retrieved oocytes, number of two-pronuclear (2PN) zygotes, and dose of recombinant FSH. RESULT(S) There was a positive correlation between CGG repeats and the level of E2 at day of hCG administration, number of retrieved oocytes, and number of 2PN zygotes. There was a negative correlation between number of CGG repeats and the total dose of gonadotropins. The E2 level and the number of retrieved oocytes and 2PN zygotes were significantly higher and the dose of gonadotropins significantly lower for premutation patients with >or=100 CGG repeats compared with <100 CGG repeats. CONCLUSION(S) There is a positive correlation between E2 level, retrieved oocytes, 2PN zygotes, and number of CGG repeats. Premutation carriers with <100 CGG repeats suffer from impaired ovarian response and decreased fertilization rate.

Does high serum progesterone level on the day of human chorionic gonadotropin administration affect pregnancy rate after intracytoplasmic sperm injection and embryo transfer

Objective. The present study was conducted to evaluate the effect of serum progesterone (P) levels on the day of human chorionic gonadotropin (hCG) administration on embryo quality and pregnancy rate in intracytoplasmic sperm injection (ICSI) cycles. Design and setting. This was a retrospective analysis conducted in the in vitro fertilization (IVF) unit of a tertiary hospital. Patients. Two hundred and one patients who underwent a total of 280 IVF treatment cycles allocated to ICSI during routine IVF/embryo transfer treatment. Results. In cycles with elevated serum P, higher estradiol levels were noted (1915 pg/ml vs. 1256 pg/ml; p<0.05), more oocytes were retrieved and manipulated, and more embryos were available for transfer. Embryo grading was comparable between the two groups. The average age was lower in the group with elevated P; but the pregnancy rate was significantly lower (16.4% vs. 27.6%, p = 0.03). Conclusions. Our data demonstrate no deleterious effect of elevated P on embryo quality. However, high serum P adversely affects implantation and pregnancy rates.

Oocyte activation: lessons from human infertility

During fertilization, the spermatozoon penetrates through the cumulus cells and the zona pellucida that surrounds the oocyte, before it binds and fuses with the oocyte plasma membrane to induce activation. In vitro fertilization (IVF) studies performed in non-human mammals have contributed extensive knowledge regarding the mechanisms by which the spermatozoon activates the meiotic-arrested oocyte to resume meiosis, cleave and develop into an embryo. Although IVF has been used extensively for treating subfertile couples, not all of them were able to benefit from this procedure. In intracytoplasmic sperm injection (ICSI), one viable spermatozoon only is sufficient for successful fertilization of a single oocyte. Moreover, the injected fertilizing spermatozoon bypasses several physiological barriers, compared with IVF, which together could explain the high success rate for this procedure. ICSI has also allowed the identification of sperm components that are required for successful fertilization.

Increasing Synthetic Serum Substitute (SSS) Concentrations in P1 Glucose/Phosphate-Free Medium Improves Implantation Rate: A Comparative Study

AbstractPurpose: To assess the comparative efficacy of IVF medium (MediCult, with 5.2 mM glucose) and a glucose/phosphate-free medium, P1 (Irvine Scientific), and to investigate the influence of increasing the serum supplementation (synthetic serum substitute; SSS; Irvine Scientific) to P1 on embryo development and implantation. Methods: Patients were randomly assigned to IVF medium (Group 1, cycles n = 172) or P1 supplemented with 10% SSS (Group 2, cycles n = 229) according to the medium scheduled for use on the day of oocyte retrieval. Another 555 IVF consequent cycles (Group 3) were performed using increased SSS concentrations (20%) in P1 medium. Results and Conclusion: In this large series of IVF cycles, we herein demonstrate that significantly higher pregnancy and implantation rates were found when embryos were cultured in glucose/phosphate-free medium P1 supplemented with 20% SSS compared to supplementation with the lower SSS concentration and with IVF medium.