Accuracy of preimplantation genetic screening (PGS) is compromised by degree of mosaicism of human embryos

Background To preclude transfer of aneuploid embryos, current preimplantation genetic screening (PGS) usually involves one trophectoderm biopsy at blastocyst stage, assumed to represent embryo ploidy. Whether one such biopsy can correctly assess embryo ploidy has recently, however, been questioned. Methods This descriptive study investigated accuracy of PGS in two ways. Part I: Two infertile couples donated 11 embryos, previously diagnosed as aneuploid and, therefore, destined to be discarded. They were dissected into 37 anonymized specimens, and sent to another national laboratory for repeat analyses to assess (i) inter-laboratory congruity and (ii) intra-embryo congruity of multiple embryo biopsies in a single laboratory. Part II: Reports on human IVF cycle outcomes after transfer of allegedly aneuploid embryos into 8 infertile patients. Results Only 2/11 (18.2 %) embryos were identically assessed at two PGS laboratories; 4/11 (36.4 %), on repeat analysis were chromosomally normal, 2 mosaic normal/abnormal, and 5/11 (45.5 %) completely differed in reported aneuploidies. In intra-embryo analyses, 5/10 (50 %) differed between biopsy sites. Eight transfers of previously reported aneuploid embryos resulted in 5 chromosomally normal pregnancies, 4 delivered and 1 ongoing. Three patients did not conceive, though 1 among them experienced a chemical pregnancy. Conclusions Though populations of both study parts are too small to draw statistically adequately powered conclusions on specific degrees of inaccuracy of PGS, here presented results do raise concerns especially about false-positive diagnoses. While inter-laboratory variations may at least partially be explained by different diagnostic platforms utilized, they cannot explain observed intra-embryo variations, suggesting more frequent trophectoderm mosiaicsm than previously reported. Together with recentl published mouse studies of lineages-specific degrees of survival of aneuploid cells in early stage embryos, these results call into question the biological basis of PGS, based on the assumption that a single trophectoderm biopsy can reliably determine embryo ploidy

Preimplantation genetic testing guidelines of International Society of Reproductive Genetics

The International Society of Reproductive Genetics (ISRG) assembled a workgroup made up of clinicians, clinical laboratory directors, and scientists for the purpose of creating the guidelines for preimplantation genetic testing (PGT). The most up-to-date information and clinical insights for the optimal PGT practice were incorporated in these guidelines. Recommendations are provided for embryologists, medical geneticists, clinical laboratorians, and other healthcare providers to improve the wellbeing of patients seeking assisted reproductive treatment and their offspring

Regulation of dsRNA-dependent protein kinase (PKR)-RNA complex

honors thesisCollege of ScienceBiochemistryPeter BealThomas G. RichmondThe activity of RNA dependant protein kinase, PKR, in the interferon signaling system has been shown to lead to inhibition of cell growth in response to a viral infection. It has been hypothesized that it is possible to control the interaction of PKR with viral RNA's using small molecular intercalators such as acridine orange. I have performed a series of experiments to study the effects of acridine orange (an intercalator of RNA) on RNA-protein complexes. These experiments complement the work of a graduate student who has designed a series of experiments referred to as SELEX to choose RNAs which are sensitive to acridine orange. In my part of the project, I was able to show that the SELEX was in fact effective at screening those RNAs whose binding to protein is sensitive to acridine orange. The study has focused on four RN As: V Al, Clone 2, 2ACR, and 2A/N. V Al and Clone 2 were chosen randomly, they were used to study the behavior of a typical small RNA molecule in the presence and absence of acridine orange. 2 ACR is an RNA chosen in the SELEX for sensitivity to acridine orange. 2 AIN was chosen as a very insensitive RNA. For the two randomly selected RNAs (VAl and Clone 2), acridine was shown to increase the Kd concentration of RBD approximately by a factor of four. However, for 2ACR acridine shifted the Kd by factor of forty, approximately ten times the normal. Gel shifts with 2A/N showed that this RNA was more resistant to acridine than either Clone 2 or V Al. Furthermore, it was shown that 56% of 2A/N bound to RBD, while 51% bound in the presence of acridine orange and 50% bound in presence of acridine yellow

New national outcome data on fresh versus cryopreserved donor oocytes

Abstract Background Improvements in oocyte cryopreservation techniques and establishment of cryopreserved donor oocyte banks have led to improved access to and lower cost of donor oocytes, upending the traditional practice of fresh oocyte donation. The objective of this study was to examine national trends in utilization and live birth rates with fresh versus cryopreserved donor oocytes. Methods A retrospective analysis of 2013 through 2015 aggregate U.S. national data reported by the Society for Assisted Reproductive Technology which included 30,160 IVF cycles with either fresh or cryopreserved donor oocytes was performed. Results During the study period utilization of fresh oocyte donations rapidly declined by 32.9%, while cryopreserved oocyte donation increased by 44.4%. Fresh donor oocytes produced significantly higher live birth rates per recipient cycle start than cryopreserved donor oocytes (51.1% vs. 39.7%). Over the three-year study period fresh donor oocytes produced stable live birth rates per recipient cycle start while those with cryopreserved oocytes significantly declined year-by-year. Conclusion Despite rising popularity of cryopreserved donor oocytes, prospective patients should be counselled that fresh donor oocytes still represent standard of care due to higher live birth rates

Degree of mosaicism in trophectoderm does not predict pregnancy potential: a corrected analysis of pregnancy outcomes following transfer of mosaic embryos

Abstract Background Preimplantation genetic screening (PGS) is increasingly utilized as an adjunct procedure to IVF. Recently healthy euploid live birth were reported following transfer of mosaic embryos. Several recent publications have surmised that the degree of trophectoderm (TE) mosaicism in transferred embryos is predictive of ongoing pregnancy and miscarriage rates. Methods This is a corrected analysis of previously published retrospective data on vitro fertilization (IVF) cycle outcomes involving replacement of 143 mosaic and 1045 euploid embryos tested by PGS, utilizing high-resolution next-generation sequencing (NGS) of TE and determination of percentages of mosaicism. Receiver operating curves (ROCs) and measurement of area under the curve (AUC) were used to evaluated the accuracy of the predictor variable, proportion of aneuploid cells in a TE biopsy specimen, with IVF outcomes, ongoing pregnancy and miscarriage rates. Results Confirming findings of the previously published report we also found higher ongoing pregnancy rates (63.3% vs. 39.2%) and lower miscarriage rates (10.2% vs. 24.3%) with euploid embryo transfers than with mosaic embryo transfer. There, however, were no significant differences in ongoing pregnancy or miscarriage rates among mosaic embryo transfers at any threshold of aneuploidy. Based on AUC, TE biopsies predicted ongoing pregnancy for euploid, as well as mosaic embryos, in a range of 0.50 to 0.59 and miscarriage in a range from 0.50 to 0.66 Conclusions Degree of TE mosaicism was a poor predictor of ongoing pregnancy and miscarriage