Conserved roles of mouse DUX and human DUX4 in activating cleavage-stage genes and MERVL/HERVL retrotransposons.

To better understand transcriptional regulation during human oogenesis and preimplantation development, we defined stage-specific transcription, which highlighted the cleavage stage as being highly distinctive. Here, we present multiple lines of evidence that a eutherian-specific multicopy retrogene, DUX4, encodes a transcription factor that activates hundreds of endogenous genes (for example, ZSCAN4, KDM4E and PRAMEF-family genes) and retroviral elements (MERVL/HERVL family) that define the cleavage-specific transcriptional programs in humans and mice. Remarkably, mouse Dux expression is both necessary and sufficient to convert mouse embryonic stem cells (mESCs) into 2-cell-embryo-like ('2C-like') cells, measured here by the reactivation of '2C' genes and repeat elements, the loss of POU5F1 (also known as OCT4) protein and chromocenters, and the conversion of the chromatin landscape (as assessed by transposase-accessible chromatin using sequencing (ATAC-seq)) to a state strongly resembling that of mouse 2C embryos. Thus, we propose mouse DUX and human DUX4 as major drivers of the cleavage or 2C state.

Comparison of 5% and ambient oxygen during days 3-5 of in vitro culture of human embryos.

OBJECTIVE: To compare the effect of two oxygen concentrations used during days 3-5 of human embryo culture on embryo quality and pregnancy outcome. DESIGN: Retrospective analysis of the use of two culture conditions. SETTING: University-based infertility clinic. PATIENT(S): Three hundred eighty-two patients undergoing IVF. INTERVENTION(S): Embryos were cultured in 5% CO(2) balanced ( approximately 20% O(2)) gas phase until day 3 then assigned to approximately 20% or reduced (5%) oxygen concentration groups and cultured until ET. MAIN OUTCOME MEASURE(S): Embryo quality, pregnancy rates, and implantation rates. RESULT(S): There were no differences in demographic features (age, type of infertility) between the two groups. The embryo scores at day 3 and day 5, blastulation rate, and transfer score did not differ between groups. No differences were observed between the 5% and 20% oxygen concentrations in the chemical pregnancy rate (71.27% vs. 78.72%), clinical pregnancy rate (58.56% vs. 64.36%), or implantation rate (44.06% vs. 44.16%). CONCLUSION(S): Reduced oxygen concentration in the gas mixture from day 3 until ET did not support better embryo development or result in higher pregnancy or implantation rates. These data do not support the hypothesis that beneficial effects of reduced oxygen concentration can be gained by employing the strategy during the latter stages of embryo culture (days 3-5) only and highlight the need for further studies through all stages of in vitro culture.

In vitro oocyte maturation and subsequent delayed fertilization is associated with increased embryo aneuploidy.

Failed fertilization and the appearance of immature oocytes are common in IVF practice; rescue intracytoplasmic sperm injection can be used as a therapy. However, this study indicates that embryos created after in vitro maturation and delayed intracytoplasmic sperm injection contain an increase in aneuploidy (79.7%) over control embryos (60.5%). Therefore, patients should be informed of the possible risk when presented with delayed intracytoplasmic sperm injection.

Comparison of four media types during 3-day human IVF embryo culture.

The aim of this study was to compare the effectiveness of human tubal fluid (HTF), G1.2, Sage Cleavage and Life Global media for IVF outcome during 3-day culture of human embryos. A three-phase auto-controlled study was conducted in which IVF outcome was compared between (1) HTF and G1.2, (2) HTF and Cleavage, and (3) Cleavage and Life Global. In phase 1, no differences in embryo quality were observed between HTF and G1.2. However, embryos derived from intracytoplasmic sperm injection (ICSI) displayed significantly improved quality when grown in HTF versus G1.2. No differences in pregnancy and implantation rates were observed in cases where embryos transferred were grown exclusively in HTF or G1.2 media. In phase 2, embryo quality was significantly improved for embryos cultured in Cleavage versus HTF media (P < 0.001). However, pregnancy, implantation and spontaneous abortion rates were similar between the two media. In phase 3, there were no differences in embryo quality, pregnancy, implantation, and spontaneous abortion rates between Cleavage and Life Global media. Overall, the data indicate that Life Global and Cleavage media yield similar results in a 3-day IVF culture programme. Cleavage medium is superior to HTF, as evidenced by significantly improved embryo quality (P < 0.001). Meanwhile, HTF medium is superior to G1.2 for ICSI cases.

Improved in vitro fertilization embryo quality and pregnancy rates with intracytoplasmic sperm injection of sperm from fresh testicular biopsy samples vs. frozen biopsy samples.

OBJECTIVE: To compare the outcomes of first-attempt IVF-intracytoplasmic sperm injection (ICSI) cycles when using fresh testicular biopsy samples vs. frozen biopsy samples. DESIGN: Retrospective chart review of 92 consecutive first-attempt IVF-ICSI cycles. SETTING: Two IVF programs. PATIENT(S): Forty consecutive first-attempt IVF-ICSI patients using sperm from fresh testicular biopsy samples and 52 consecutive first-attempt IVF-ICSI cycles using frozen testicular biopsy samples. INTERVENTION(S): Testicular biopsy, IVF-ICSI with fresh and frozen-thawed spermatozoa. MAIN OUTCOME MEASURE(S): Fertilization rates, embryo quality, pregnancy, delivery, and spontaneous abortion rates. RESULT(S): A significantly increased ICSI fertilization percentage was obtained with frozen testicular biopsy samples (76.5% +/- 3.1%) vs. fresh biopsy samples (68.3% +/- 2.6%). However, embryo quality, pregnancy, and delivery rates were higher in the fresh biopsy group. Mean embryo score was 4.54 +/- 0.31 and 3.62 +/- 0.2 in the fresh vs. frozen group, respectively. Chemical pregnancy rates (60% vs. 49.1%), clinical pregnancy rates (56.4% vs. 41.2%), and delivery rates (48.7% vs. 31.2%) were each higher in the fresh group vs. frozen group. Accordingly, the spontaneous abortion rate was lower in the fresh group (21.7%) vs. the frozen group (33.3%). CONCLUSION(S): Although the use of frozen biopsy samples has logistical advantages, we conclude it may be advantageous to use fresh testicular biopsy samples in IVF-ICSI cases whenever possible, as fresh specimens yielded significantly improved embryo quality, generally higher pregnancy rates, and lower spontaneous abortion rates.

Elevated sperm chromosome aneuploidy and apoptosis in patients with unexplained recurrent pregnancy loss.

OBJECTIVE: To evaluate sperm chromosome aneuploidy and semen quality in 24 partners of women with unexplained recurrent pregnancy loss and to analyze the data in relation to sperm apoptosis data. METHODS: Semen quality parameters and sperm chromosome aneuploidy for chromosomes X, Y, 13, 18, and 21 were evaluated in the recurrent pregnancy loss patients, fertile controls, and a control group of men from the general population. RESULTS: The mean aneuploidy rate in the recurrent pregnancy loss group was 2.77 +/- 0.22, significantly higher (P <.005) than in either the general population (1.48 +/- 0.12) or in fertile (1.19 +/- 0.11) control groups. In the recurrent pregnancy loss patients, the percentage of aneuploid sperm was correlated to the percentage of apoptotic sperm (r =.62, P <.001). Normal morphology was diminished in the patient group, compared with the general population group (P <.01) and the donor group (P <.001). CONCLUSIONS: These data indicate that some recurrent pregnancy loss patients have a significant increase of sperm chromosome aneuploidy, apoptosis, and abnormal sperm morphology. This study demonstrates a new possible cause of recurrent pregnancy loss.