To evaluate the role of endometrial thickness and pattern in in-vitro fertilization (IVF), these parameters were prospectively measured in 516 cycles of IVF with embryo transfer at our clinic. Pregnancy and embryo implantation rates were assessed for each mm of endometrial thickness and for each of three endometrial patterns. Embryo implantation, clinical and ongoing pregnancy rates were significantly higher in the patients with an endometrial thickness >9 mm (24.4, 48.6 and 42.2% respectively) compared with those of 9 mm as well as ring and intermediate endometrial patterns denoted a more favourable prognosis for pregnancy in IVF but thinner endometrium and those exhibiting a solid configuration had an acceptable pregnancy outcome.
The purpose of this study was to devise an embryo score to predict the likelihood of successful implantation after in-vitro fertilization (IVF), Unlike most studies dealing with the influence of embryo stage and morphology on pregnancy, our study was based on single rather than multiple embryo transfers, A total of 957 single embryo transfers were carried out, No delivery was obtained after any of the 99 transfers using 1-cell embryos or embryos obtained after delayed fertilization, In the remaining 858 transfers, the embryos had cleaved, Higher pregnancy rates were obtained with embryos displaying no irregular cells (11.7 versus 6.9%; P 38 years (8.2 versus 11.4%; P < 0.05), even though embryo quality was similar regardless of age, Single embryo transfer allowed us to define a simple and useful embryo score to choose the best embryo for transfer to optimize NF and embryo transfer outcome, The use of this embryo score could decrease multiple pregnancies after multiple embryo transfers.
Expression of 72 kDa and 92 kDa type IV collagenases and the metalloproteinase inhibitors TIMPs 1, 2, and 3 was studied by in situ hybridization in implanting mouse embryos of days 5.5 to 7.5. The 92 kDa type IV collagenase was strongly expressed in invading trophoblasts, signals above background not being observed in the embryonic proper or placental tissue. In contrast, signals above background were not seen for the 72 kDa enzyme in any cells of the implantation region, including trophoblasts and stromal cells of the decidual tissue. Only cells in the mucosal stroma outside the decidual region displayed some expression. TIMP-3 was intensily expressed in maternal cells in the area surrounding the invading embryonic tissue. No expression was observed for TIMP-1 or TIMP-2 in the embryo proper, trophoblasts, or the area of the uterine decidual reaction. Weak signals appeared for TIMP-1 only in the circular layer of myometrial smooth muscle and in some uterine stroma cells distant from the site of embryo implantation. The results suggest a central role for 92 kDa type IV collagenase and TIMP-3 in the extracellular proteolysis associated with implantation of the early embryo. (C) 1995 Wiley-Liss, Inc.
Mammalian preimplantation embryos normally develop within the protected environment of the female reproductive tract, which virtually precludes studies on embryogenesis in situ. Information must therefore be derived from experiments on cultured embryos. Consequently, studies on the epigenetic regulation of embryogenesis have long been interwoven with efforts to formulate culture media capable of sustaining normal development. In this review, comparative information on epigenetic regulation of embryo development is discussed, including information on energy substrate and amino acid preferences of embryos. Advantages of simple versus complex culture media, and of substituting serum albumin or synthetic macromolecules for serum, are discussed. Some potential pitfalls of co-culture are described. Culture appears to induce anomalies in embryo metabolism, which may derive from disturbed intracellular pH. Rationales for selecting endpoints to evaluate the outcome of experiments are considered, including incorporation of timing of embryo development into the analysis. Poor experimental design and/or data analysis can detract from or even negate the value of data obtained from embryo culture; examples are examined to help correct this problem. All of these points are discussed with a view to using data on the needs of embryos for making improvements in the design of culture media, so that higher yields and increased viability of embryos are achieved.
Gene targeting was used to create a null allele at the epidermal growth factor receptor locus (Egfr). The phenotype was dependent on genetic background. EGFR deficiency on a CF-1 background resulted in peri-implantation death due to degeneration of the inner cell mass. On a 129/Sv background, homozygous mutants died at mid-gestation due to placental defects; on a CD-1 background, the mutants lived for up to 3 weeks and showed abnormalities in skin, kidney, brain, liver, and gastrointestinal tract. The multiple abnormalities associated with EGFR deficiency indicate that the receptor is involved in a wide range of cellular activities.
Several retrospective analyses of our in-vitro fertilization (IVF) and oocyte donation programmes have been carried out in an attempt to gain clinical knowledge of the factors implied in the aetiology of endometriosis-associated infertility, In a first approach, a comparison was made of the IVF outcome between 96 cycles in 78 patients with tubal infertility and 96 more cycles in 59 women with endometriosis. The results indicate that endometriosis patients had a poor IVF outcome in terms of a reduced pregnancy rate per cycle (P < 0.0004), a reduced pregnancy rate per transfer (P < 0.002) and a reduced implantation rate per embryo replaced (P < 0.003), In a second study, we addressed the analysis of patients undergoing oocyte donation, The results showed that patients with this disease have the same chances of implantation and embryo development in vivo as other recipients when the oocytes come from donors without known endometriosis. However, when the results of oocyte donation were classified according to the nature of the oocytes donated, patients who received embryos derived from endometriotic ovaries showed a significantly (P < 0.05) reduced ability to implant compared with the remaining groups, In a third approach, we evaluated embryo development in vitro when women with and without endometriosis underwent IVF and embryo replacement 72 h after oocyte retrieval, We observed a significantly (P < 0.04) reduced number of blastomeres in embryos from endometriosis patients compared with controls, as well as an increased (P < 0.05) incidence of arrested embryos in vitro, Taken together, these observations suggest that infertility in endometriosis patients may be related to alterations within the oocyte which, in turn, result in embryos of lower quality, as demonstrated in our IVF programme, and a lower ability to implant, as shown in the oocyte donation model.
A synchrony between the activated state of the blastocyst and differentiation of the uterus to the receptive state is essential to the process of implantation. This process is directed by progesterone (P4) and estrogen. The mechanism by which P4 differentiates the uterus, enabling estrogen to initiate implantation, is unknown but likely to involve localized induction of growth and differentiation factors. We have cloned the murine amphiregulin (AR) gene, a newly discovered member of the: epidermal growth factor family, and demonstrate that its expression is implantation-specific and P4-regulated in the mouse uterus. A transient surge in AR mRNA levels occurred throughout the uterine epithelium on day 4 of pregnancy. With the onset of blastocyst attachment late on day 4, AR mRNA accumulated in the luminal epithelium exclusively at the sites of blastocysts. Thus, AR expression correlated first with rising P4 levels and then with the attachment reaction. The rapid induction of AR mRNA in the ovariectomized uterus only by P4 and abrogation of this induction by RU-486 (a P4 receptor antagonist) suggest that this uterine gene is regulated by P4. AR appeared to exhibit preferential phosphorylation of epidermal growth factor receptor in the uterus over that in the blastocyst. This is a first report of a P4-regulated uterine epithelial cell growth factor that is associated with epithelial cell differentiation during implantation. The association of AR in implantation is further documented by its down-regulation in the day 4 pregnant uterus in which uterine receptivity and implantation were disrupted by estrogen or RU-486 treatment on day 3. These results further indicate that the expression of the AR gene could serve as a molecular marker for the receptive state of the uterus for implantation.
Non-invasive selection of transgenic mice was performed at the stage of preimplantation embryos, The morulae collected from wild female mated with hemizygous transgenic male expressing Aequorea victoria green fluorescent protein (GFP) under chicken beta-actin promoter could be classified as green or non-green under a fluorescent microscope, All the green embryos were shown to carry the transgene by PCR analysis, Taking advantage of the detection of GFP expression can be done non-invasively, the selected embryos mere demonstrated to be able to developed to term with 100% of accuracy of the selection.