Biomarkers in Reproductive Medicine: Toward Selecting the Best IVF Embryo for Transfer
Embryonic chromosomal aneuploidies are the major genetic cause of infertility in humans. As a result, preimplantation genetic diagnosis for aneuploidy (PGT-A) has emerged as a technology that allows clinicians to select only chromosomally normal embryos for uterine transfer, resulting in remarkably higher delivery rates, lower miscarriage rates and improved cost-effectiveness of in vitro fertilization treatments. Nevertheless, even after selective transfer of euploid embryos, around one third of these chromosomally normal embryos fail to implant and result in a healthy pregnancy, which highlights the need to investigate additional factors and biomarkers for embryonic reproductive competence. This thesis approaches three major areas of preimplantation embryo development in order to develop tools to investigate for biomarkers for embryonic competence, thus improving embryo selection before transfer: The embryonic transcriptome, embryo single nucleotide polymorphism (SNP) genotyping and extracellular vesicles (EVs). First, a novel and unique method is proposed that assesses both gene expression and chromosome copy number form the same trophoectoderm biopsy. Second, SNP genotyping data generated in parallel with chromosome copy number analysis by targeted next generation sequencing is investigated to improve embryo selection by deciphering cases of embryo polyploidy and unmasking false-positive cases of chromosomal mosaicism. Finally, given that EVs have been described as major key players of intercellular communication and a molecular dialog between the embryo and the endometrium is responsible for correct embryo implantation, this thesis aimed to explore the potential of EVs present in the embryo spent culture medium as potential biomarkers of reproductive success. Three methods for isolation of EVs were tested in embryo spent medium microdrops so as to facilitate research on EVs at a single embryo level, therefore paving the way for the discovery of EV biomarkers.
Genetics|Molecular biology|Developmental biology
Marin, Diego, "Biomarkers in Reproductive Medicine: Toward Selecting the Best IVF Embryo for Transfer" (2019). ETD Collection for Thomas Jefferson University. AAI27542408.