A simple and rapid flow cytometry-based assay to identify a competent embryo prior to embryo transfer

Multiple pregnancy is a risk for prematurity and preterm birth. The goal of assisted reproduction is to achieve a single pregnancy, by transferring a single embryo. This requires improved methods to identify the competent embryo. Here, we describe such a test, based on flow cytometric determination of the nucleic acid (PI+) containing extracellular vesicle (EV) count in day 5 embryo culture media. 88 women undergoing IVF were included in the study. More than 1 embryos were transferred to most patients. In 58 women, the transfer resulted in clinical pregnancy, whereas in 30 women in implantation failure. In 112 culture media of embryos from the "clinical pregnancy" group, the number of PI+ EVs was significantly lower than in those of 49 embryos, from the "implantation failure" group. In 14 women, transfer of a single embryo resulted in a singleton pregnancy, or, transfer of two embryos in twin pregnancy. The culture media of 19 out of the 20 "confirmed competent" embryos contained a lower level of PI+ EVs than the cut off level, suggesting that the competent embryo can indeed be identified by low PI+ EV counts. We developed a noninvasive, simple, inexpensive, quick test, which identifies the embryos that are most likely to implant

Endometrial stromal cells of women with recurrent miscarriage fail to discriminate between high- and low-quality human embryos

Background The aetiology of recurrent miscarriage (RM) remains largely unexplained. Women with RM have a shorter time to pregnancy interval than normally fertile women, which may be due to more frequent implantation of non-viable embryos. We hypothesized that human endometrial stromal cells (H-EnSCs) of women with RM discriminate less effectively between high-and low-quality human embryos and migrate more readily towards trophoblast spheroids than H-EnSCs of normally fertile women. Methodology/Principal Findings Monolayers of decidualized H-EnSCs were generated from endometrial biopsies of 6 women with RM and 6 fertile controls. Cell-free migration zones were created and the effect of the presence of a high-quality (day 5 blastocyst, n = 13), a low-quality (day 5 blastocyst with three pronuclei or underdeveloped embryo, n = 12) or AC-1M88 trophoblast cell line spheroid on H-ESC migratory activity was analyzed after 18 hours. In the absence of a spheroid or embryo, migration of H-EnSCs from fertile or RM women was similar. In the presence of a low-quality embryo in the zone, the migration of H-EnSCs of control women was inhibited compared to the basal migration in the absence of an embryo (P<0.05) and compared to the migration in the presence of high-quality embryo (p<0.01). Interestingly, the migratory response H-EnSCs of women with RM did not differ between high- and low-quality embryos. Furthermore, in the presence of a spheroid their migration was enhanced compared to the H-EnSCs of controls (p<0.001). Conclusions H-EnSCs of fertile women discriminate between high- and low-quality embryos whereas H-EnSCs of women with RM fail to do so. H-EnSCs of RM women have a higher migratory response to trophoblast spheroids. Future studies will focus on the mechanisms by which low-quality embryos inhibit the migration of H-EnSCs and how this is deregulated in women with RM

Comprehensive analysis of karyotypic mosaicism between trophectoderm and inner cell mass

Aneuploidy has been well-documented in blastocyst embryos, but prior studies have been limited in scale and/or lack mechanistic data. We previously reported preclinical validation of microarray 24-chromosome preimplantation genetic screening in a 24-h protocol. The method diagnoses chromosome copy number, structural chromosome aberrations, parental source of aneuploidy and distinguishes certain meiotic from mitotic errors. In this study, our objective was to examine aneuploidy in human blastocysts and determine correspondence of karyotypes between trophectoderm (TE) and inner cell mass (ICM). We disaggregated 51 blastocysts from 17 couples into ICM and one or two TE fractions. The average maternal age was 31. Next, we ran 24-chromosome microarray molecular karyotyping on all of the samples, and then performed a retrospective analysis of the data. The average per-chromosome confidence was 99.95%. Approximately 80% of blastocysts were euploid. The majority of aneuploid embryos were simple aneuploid, i.e. one or two whole-chromosome imbalances. Structural chromosome aberrations, which are common in cleavage stage embryos, occurred in only three blastocysts (5.8%). All TE biopsies derived from the same embryos were concordant. Forty-nine of 51 (96.1%) ICM samples were concordant with TE biopsies derived from the same embryos. Discordance between TE and ICM occurred only in the two embryos with structural chromosome aberration. We conclude that TE karyotype is an excellent predictor of ICM karyotype. Discordance between TE and ICM occurred only in embryos with structural chromosome aberrations

Approaches to improve the diagnosis and management of infertility

Recent advances in our understanding of the causes of infertility and of assisted reproductive technology (ART) have led to the development of complex diagnostic tools, prognostic models and treatment options. The Third Evian Annual Reproduction (EVAR) Workshop Meeting was held on 26-27 April 2008 to evaluate evidence supporting current approaches to the diagnosis and management of infertility and to identify areas for future research efforts. Specialist reproductive medicine clinicians and scientists delivered presentations based on published literature and ongoing research on patient work-up, ovarian stimulation and embryo quality assessment during ART. This report is based on the expert presentations and subsequent group discussions and was supplemented with publications from literature searches and the authors' knowledge. It was agreed that single embryo transfer (SET) should be used with increasing frequency in cycles of ART. Continued improvements in cryopreservation techniques, which improve pregnancy rates using supernumerary frozen embryos, are expected to augment the global uptake of SET. Adaptation and personalization of fertility therapy may help to optimize efficacy and safety outcomes for individual patients. Prognostic modelling and personalized management strategies based on individual patient characteristics may prove to represent real progress towards improved treatment. However, at present, there is limited good-quality evidence to support the use of these individualized approaches. Greater quality control and standardization of clinical and laboratory evaluations are required to optimize ART practices and improve individual patient outcomes. Well-designed, good-quality studies are required to drive improvements to the diagnosis and management of ART processes

Telomeric probes for fish : technical aspects and clinical applications

Terminal regions of chromosomes are frequently involved in structural chromosomal abnormalities and are prone to rearrangements. They are also gene rich, and have been shown to be associated with a number of clinical conditions. This study focuses on telomere-specific fluorescence in situ hybridization (FISH) probes. It addresses the technical aspects of their preparation and application, and examines whether FISH using these probes is a valuable tool for detection of aberrations in the terminal regions of chromosomes. A set of telomere specific probes was generated from half yeast artificial chromosome (YAC) and cosmid clones by DNA preparation via Alu-PCR, alkaline lysis, cesium chloride-ethidium bromide centrifugation, or using a "Qiagen" kit. Probe quality and optimal FISH conditions were established by hybridizing half-YACs specific to telomeres 21q, 18q, 10p, and cosmids for telomeres 2q/8p, 13q, 14q and 20p to normal metaphases. Probes for 10p, 13q, 14q, 18q and 21q yielded clear and specific hybridization signals, present in over 90% of metaphases analyzed. Interphase analysis using the probes was not accurate. The ability of the telomeric probes to characterize balanced and unbalanced abnormalities was established by hybridization to patients with previously diagnosed chromosomal aberrations. The probes identified and confirmed partial trisomies 21q, 18q, and balanced translocations t(8;14), t(6;14), t(8;18), t(5;10). In three of the cases, partial monosomy 18q, translocation t(10;13), and t(1;10), the probes were able to provide information which was not revealed by banding analysis. This study demonstrates the ability of telomere specific probes to characterize aberrations in the terminal regions of chromosomes, and concludes that FISH using the telomeric probes is a valuable tool for clinical cytogenetics

Chromosomal mosaicism in the human preimplantation embryo in vitro

It has previously been demonstrated that a large percentage of in vitro generated human embryos are chromosomally mosaic. The current thesis investigated this mosaicism in greater detail. It characterized the mosaicism present at each stage of preimplantation development in vitro. It examined the relevance of the different forms of the observed mosaicism to preimplantation embryo wastage, implantation failure, and fetal and placental mosaicism. Finally, it addressed the identification of the chromosomally mosaic embryos during preimplantation genetic diagnosis (PGD). For each of the studies presented within the thesis, blastomeres from "spare" in vitro generated embryos were assessed for chromosomal content using multi-color fluorescence in situ hybridization (FISH) DNA probes. Mosaicism was detected at all stages of preimplantation development, from the 2-cell stage to the blastocyst stage; it comprised of diploid, aneuploid, "chaotic", haploid, and polyploid chromosome patterns. Compared to blastocysts, arrested embryos or embryos at the earlier stages of development, showed a much higher incidence of mosaicism involving "chaotic" imbalances for multiple chromosomes and/or high percentages of abnormal cells. These results indicate that extensive post-zygotic abnormalities impair embryonic development to the blastocyst stage. The presence of mosaicism was not predicted by embryo morphology. Mosaicism may therefore contribute to the low rates of blastocyst formation in vitro and to the high rates of implantation failure following cleavage stage embryo transfer. Probe mixtures comprising of three autosomes, of one autosome and gonosomes, or of five autosomes could be applied for the identification of the mosaic embryos during cleavage stage PGD. Culture of isolated blastomeres from cleavage stage embryos for genetic diagnosis increases the number of cells available for analysis; however, the presence of nuclear defects and mosaicism among the cultured cells indic