Faculty Bibliography

OBJECTIVE: To report a case of gestational carrier pregnancy with oocytes from a stage IIIc ovarian cancer patient. DESIGN: Case report. SETTING: University hospital. PATIENT: A 38-year-old woman with stage IIIc ovarian cancer. INTERVENTION(S): Controlled ovarian stimulation, cancer surgery, and IVF-ET to a gestational carrier. MAIN OUTCOME MEASURE(S): Oocyte fertilization and pregnancy. RESULT(S): Singleton term delivery occurred after transfer of three frozen-thawed embryos. CONCLUSION(S): Cryopreservation of embryos derived from IVF of oocytes obtained from ovarian cancer patients should be an option for their future fertility

In mammals, the dynamic reprogramming of DNA methylation begins during gametogenesis and continues through embryogenesis. Recently, immunofluorescence staining with an antibody against 5-methylcytosine (anti-5-MeC) has revealed active demethylation of the male pronucleus in zygotes beginning at 4-6 h after fertilization. In this study, we characterized the DNA methylation patterns in mouse zygotes and in human tripronucleate (3 PN) zygotes discarded after conventional fertilization or following ICSI. Pronuclei were subjected to fluorescence in-situ hybridization to identify the X and/or Y chromosomes and then stained with anti-5-MeC. In diandric 3 PN zygotes from conventional IVF, we consistently observed one strongly and two weakly stained pronuclei. In contrast, the majority of 3 PN ICSI zygotes, mainly digynic zygotes, displayed two strongly and one weakly stained pronuclei. Two zygotes from ICSI failed to show any staining difference among the three pronuclei. Our results indicate that the active demethylation of male pronuclei occurs in both mouse and human zygotes. It is possible that the abnormal methylation patterns resulting from a dysfunctional cytoplasm may occur in a small number of oocytes and may affect embryonic viability

Cell allocation and subsequent lineage commitment in the human embryo may be established as early as in the unfertilized oocyte. This phenomenon might be the result of subtle differences of gene expression and protein distribution. To assess whether gene expression profiling by reverse transcription-polymerase chain reaction could be a suitable tool for the detection of cell allocation and lineage commitment, the expression pattern of the putative inner cell mass marker gene Oct-4 and the trophectodermal marker genes beta-HCG and beta-LH were correlated in individual blastomeres of preimplantation human embryos. In 2- to 5-cell stage embryos, expression of beta-HCG and Oct-4 mRNA was negatively correlated in all blastomeres with statistical significance, suggesting that cell allocation can be assessed by those markers at early stages. In 7- to 10-cell stage embryos, expression of beta-LH and Oct-4 mRNA was negatively correlated in some blastomeres without statistical significance, suggesting that more experiments are necessary to decide if lineage commitment can be assessed in some cells by those markers at later stages