Chun-Kai Chen

The Relationship of Pronuclear Stage Morphology and Chromosome Status at Cleavage Stage

AbstractPurpose: Infertile couples undergoing in vitro fertilization-embryo transfer (IVF-ET) program were included to study the relationship of pronuclear stage morphology and chromosome status at cleavage stage. Methods: Eighteen to twenty-one hours after fertilization, zygotes were checked for pronuclear morphology with modified Scott Z-score system. After embryo transfer on day 3, arrested or non-transferred 2 PN embryos were spread for fluorescence in situ hybridization (FISH) staining of probes to chromosomes 18, X and Y. Results: Ninety-eight embryos were successfully fixed and stained. The chromosome status were recorded in each 2 PN score group: 7 (54%) of 13 embryos in Z2 group, 14 (35%) of 40 in Z3 group and 10 (36%) of 28 in Z4 group being normal diploid. Z1 group has 12 (71%) of 17 embryos being normal diploid, which is significantly more than Z3 (p=0.020) and Z4 group (p = 0.033). Conclusion: Our results demonstrated a high probability to get normal diploid embryos if good morphology at pronuclear stage was used as selection criteria, especially for Z1 score embryos.

Monozygotic twinning after in vitro fertilization/intracytoplasmic sperm injection treatment is not related to advanced maternal age, intracytoplasmic sperm injection, assisted hatching, or blastocyst transfer

OBJECTIVE To evaluate the effect of assisted reproductive techniques on the incidence of monozygotic twins (MZT) and the associated pregnancy outcomes. MATERIALS AND METHODS This was a retrospective study of all in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles with MZT pregnancies in our center from January 2001 to December 2011. The diagnosis of MZT pregnancies with their respective placental configurations was based on the results of ultrasonographic examinations performed during either the first or second trimester. The treatment characteristics and outcomes of each IVF cycle were recorded and stored in a computer database. RESULTS A total of 17 cycles with MZT pregnancies were identified, resulting in an overall incidence of MZT of 1.3%. The incidence of MZT for women aged <35 years and ≥35 years were 1.5% and 0.8%, respectively (p = 0.319). The incidence was not significantly different between ICSI and non-ICSI cycles (1.4% vs. 1.0%; p = 0.620). In addition, the incidence was not increased in the assisted hatching (AH) group compared to those without AH (0.9% vs. 2.1%; p = 0.103). Finally, cycles with embryo transfer at the blastocyst stage had an MZT incidence that was not significantly different from those transferred at the cleavage stage (1.4% vs. 1.3%, respectively; p = 1.000). The incidence of each type of chorionicity, dichorionic-diamniotic, monochorionic-diamniotic, and monochorionic-monoamniotic, was 33.3%, 46.7%, and 20.0%, respectively. A total of 11 of 39 (28%) monozygotic babies and 16 of 19 (84%) coexisting heterozygotic babies were born alive. CONCLUSION Until definite conclusions are drawn from larger trials, patients receiving IVF should not be overly concerned about the increase in MZT risk when proceeding to various assisted reproductive procedures (i.e., ICSI, AH, and blastocyst transfer). However, there is some evidence that the incidence of monochorionic-monoamniotic twins may be significantly increased after IVF/ICSI cycles. Patients should be informed about the possible obstetric complications regarding this rare type of MZT.

New perspectives on preimplantation genetic diagnosis and preimplantation genetic screening

Preimplantation genetic diagnosis is a procedure that involves the removal of one or more nuclei from oocytes (a polar body) or embryos (blastomeres or trophectoderm cells) in order to test for problems in genome sequence or chromosomes of the embryo prior to implantation. It provides new hope of having unaffected children, as well as avoiding the necessity of terminating an affected pregnancy for genetic parents who carry an affected gene or have balanced chromosomal status. Polymerase chain reaction-based molecular techniques are the methods used to detect gene defects with a known sequence and X-linked diseases. The indication for using this approach has expanded for couples who are prevented from having babies because they carry a serious genetic disorder to couples with conditions that are not immediately life threatening, such as cancer predisposition genes and Huntington disease. In addition, fluorescent in situ hybridization (FISH) has been widely applied for the detection of chromosome abnormalities. FISH allows the evaluation of many chromosomes at the same time, up to 15 chromosome pairs in a single cell. Preimplantation genetic screening, defined as a test that screens for aneuploidy, has been most commonly used in situations of advanced maternal age, a history of recurrent miscarriage, a history of repeated implantation failure, or a severe male factor. Unfortunately, randomized controlled trials have as yet shown no benefit with respect to preimplantation genetic screening using cleavage stage biopsy, which is probably attributable to the high levels of mosaicism at early cleavage stages and the limitations of FISH. Recently, two main types of array-based technology combined with whole genome amplification have been developed for use in preimplantation genetic diagnosis; these are comparative genomic hybridization and single nucleotide polymorphism-based arrays. Both allow the analysis of all chromosomes, and the latter also allows the haplotype of the sample to be determined. The promising results of these two approaches will inspire further validation of these array platforms, even at the single-cell level. It remains to be decided which embryo stage is the best for biopsy. Moreover, if randomized controlled trials are confirmed to play a role in increasing delivery rates, this will be a major step forward for assisted reproductive technology patients around the world.

Gonadotrophin-releasing hormone antagonist induces apoptosis in human decidual stromal cells: effect on GADD45α and MAPK signaling

BACKGROUND The impact of gonadotrophin-releasing hormone (GnRH) antagonists used in IVF protocols on endometrial tissue remodeling, embryo implantation and the programming of early pregnancy is still unclear. Pregnancy and infant outcomes after treatment with GnRH antagonist for IVF are particular causes of concern. The purpose of this study was to investigate the mechanisms of GnRH antagonist-induced apoptosis of human decidual stromal cells and the effects of GnRH antagonist on the activation of ERK1/2, JNK and GADD45α signaling. METHODS Human decidual stromal cells were isolated from decidual tissue. The expression of GnRH-I receptor (GnRH-IR) was examined by immunoblot analysis and immunohistochemistry. The cells were treated with the GnRH antagonist, Cetrorelix. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay was used to examine cell viability. Cleaved caspase-3 and terminal deoxynucleotidyl transferase-mediated dUDP nick-end labeling assay were used as indicators for cell apoptosis. Mitogen-activated protein kinase function was tested for the elucidation of intracellular signalings through the pre-treatment of stromal cells with ERK1/2 (U0126) and JNK (SP600125) inhibitors prior to the Cetrorelix treatment. To characterize the signaling pathway of GnRH antagonist, the endogenous GnRH-IR and GADD45α were knocked down by specific small-interfering RNA (siRNA). RESULTS The GnRH-IR is expressed in human decidual stromal cells. Treatment with GnRH antagonist decreased cell viability, induced apoptosis and increased the phosphorylation of ERK1/2 and JNK. Cells pre-treated with U0126 and SP600125 were rescued from the GnRH antagonist-mediated inhibition of cell growth and did not exhibit GnRH antagonist-induced apoptosis and downstream GADD45α signaling. GnRH antagonist-mediated cell growth inhibition and apoptosis were also abolished by the knockdown of the endogenous GnRH-IR or GADD45α with siRNAs. CONCLUSIONS The GnRH antagonist suppresses the growth of decidual stromal cells by inducing apoptosis through the GnRH-IR and through the ERK1/2 and JNK phosphorylation-dependent induction of GADD45α signaling. These results indicate that ERK1/2, JNK and GADD45α are coordinately regulated by the GnRH antagonist through the GnRH-IR to induce apoptosis in human decidual stromal cells, suggesting that the GnRH antagonist may play a role in decidual programming in human pregnancy.

Preimplantation genetic diagnosis by fluorescence in situ hybridization of reciprocal and Robertsonian translocations

OBJECTIVE The presence of reciprocal and Robertsonian chromosomal rearrangement is often related to recurrent miscarriage. Using preimplantation genetic diagnosis, the abortion rate can be decreased. Cases treated at our center were reviewed. MATERIALS AND METHODS A retrospective analysis for either Robertsonian or reciprocal translocations was performed on all completed cycles of preimplantation genetic diagnosis at our center since the first reported case in 2004 until the end of 2010. Day 3 embryo biopsies were carried out, and the biopsied cell was checked by fluorescent in situ hybridization using relevant informative probes. Embryos with a normal or balanced translocation karyotype were transferred on Day 4. RESULTS Thirty-eight preimplantation genetic diagnosis cycles involving 17 couples were completed. A total of 450 (82.6%) of the total oocytes were MII oocytes, and 158 (60.0%) of the two-pronuclei embryos were biopsied. In 41.4% of the fluorescent in situ hybridization analyses, the results were either normal or balanced. Embryos were transferred back after 21 cycles. Three babies were born from Robertsonian translocation carriers and another two from reciprocal translocation carriers. The miscarriage rate was 0%. Among the reciprocal translocation group, the live delivery rate was 8.3% per ovum pick-up cycle and 18.2% per embryo transfer cycle. Among the Robertsonian translocation group, the live delivery rate was 14.3% per ovum pick-up cycle and 20.0% per embryo transfer cycle. CONCLUSION There is a trend whereby the outcome for Robertsonian translocation group carriers is better than that for reciprocal translocation group carriers. Aneuploidy screening may possibly be added in order to improve the outcome, especially for individuals with an advanced maternal age. The emergence of an array-based technology should help improve this type of analysis.

Low-dose GnRH antagonist protocol is as effective as the long GnRH agonist protocol in unselected patients undergoing in vitro fertilization and embryo transfer.

OBJECTIVE The present retrospective and controlled comparative study was designed to evaluate the pregnancy rate achieved using a modified, fixed, multiple-dose 0.125mg gonadotropin-releasing hormone (GnRH) antagonist protocol with the long GnRH agonist protocol as the control group. MATERIALS AND METHODS One hundred and twenty unselected women between 30 and 40 years of age, in their first cycle of IVF/ICSI, with a baseline follicle-stimulating hormone (FSH) <10 IU and an antral follicle count >3 were assigned into two groups: (1) the study group received 0.125mg of cetrorelix daily starting on Day 6 of stimulation; and (2) the control group received leuprolide daily starting in the mid-luteal phase of the preceding cycle. Both groups were given a flexible dose of recombinant FSH for stimulation. An ongoing pregnancy rate of more than 12 weeks was the primary outcome measure of the study. RESULTS Primary and secondary outcomes were comparable in both groups. A shorter duration of stimulation, a lower dosage of recombinant FSH consumption and a thinner endometrium on the day of human chorionic gonadotropin administration were all observed in the GnRH antagonist group. CONCLUSION A dosage of 0.125mg GnRH antagonist protocol was effective for these unselected patients during IVF/ET.

Resumption of Meiosis-I After Transfer of Mouse Primordial Oocytes from Frozen-Thawed Ovarian Tissue to Enucleated Preovulatory Oocytes: A Preliminary Report

AbstractPurpose: Ovarian tissue banking may be the best strategy to preserve female fertility. But optimal method to obtain viable mature oocytes remains challenging. In order to bypass the long in vitro oocyte growth period, we developed this study to test whether reconstruction of thawed primordial oocytes with enucleated preovulatory germinal vesicle (GV) oocytes could induce dictyate nuclei to undergo chromosomal condensation and meiotic maturation. Methods: Isolated primordial oocytes from thawed mouse ovarian tissue were reconstructed with enucleated GV oocytes. After electrofusion and in vitro maturation, the reconstituted oocytes were assessed for first polar body extrusion, cytoskeleton configuration, and chromosome abnormalities. Results: Primordial oocytes from thawed ovarian tissue showed a high survival rate. Following transfer and electrofusion, they could be fused with enucleated GV oocytes (35.6%, 36/101) and extruded a first polar body (52.8%, 19/36). These mature oocytes showed a normal spindle configuration and chromosome number. Conclusions: We successfully established a mouse cell model to prove that omitting the whole growth and maturation period by transfer of primordial oocytes to developmentally older enucleated oocytes would bypass the long growth period required to the preovulatory stage. Polar body extrusion could also ensue after in vitro growth. This study provided an alternative approach for future investigations in oocyte maturation.