Novel strategy with potential to identify developmentally competent IVF blastocysts

BACKGROUND: Currently there are no markers fully predictive of developmental competence of human IVF embryos. The present study investigated a novel strategy involving blastocyst biopsy and DNA fingerprinting to link developmental competence with gene expression patterns. METHODS: Patient's blastocysts were biopsied to remove 8-20 trophectoderm (TE) cells for molecular analysis prior to transfer. Biopsy samples were amplified and gene expression was evaluated using microarrays. Sibling TE biopsies and cells from resulting offspring were subjected to DNA fingerprinting to identify which blastocyst(s) in the transfer cohort developed to term. RESULTS: Blastocyst biopsy did not appear to impair developmental competence. Comparative microarray analysis of cDNA from pooled 'viable' and 'non-viable' TE samples identified over 7000 transcripts expressed exclusively in 'viable' blastocysts. The most significant of these included transcripts involved in cell adhesion and cell communication, key processes that have been associated with mammalian implantation. DNA fingerprinting of three cohorts of sibling blastocysts identified those blastocyst(s) that produced term pregnancies. CONCLUSIONS: The combination of blastocyst biopsy, microarray gene expression profiling and DNA fingerprinting is a powerful tool to identify diagnostic markers of competence to develop to term. This strategy may be used to develop a rapid diagnostic assay or for refining existing criteria for the selection of the single most viable blastocyst among a cohort developing in vitro.