Interaction between gene expression and morphokinetic parameters in undisturbed human embryo culture
The clinical in vitro fertilisation (IVF) need for optimal culture conditions and improved selection of human embryos for transfer led to the development of time-lapse systems built into incubators to allow a stable, well-defined and undisturbed culture environment with continual monitoring of embryo development. Clinical data suggest that both undisturbed culture of embryos and selection algorithms based on time-lapse morphometric parameters can potentially improve embryo development and live birth rates. However, there remains a need to validate and understand the mechanisms underlying the potential benefits of the time-lapse technology in IVF. In this study, we compared the gene expression of human embryos grown in an undisturbed time-lapse system with a conventional incubator and showed that there is no fundamental difference in the developmental program of the undisturbed embryos, which provides important reassurance concerning the time-lapse technology. We then performed a network-based integrative analysis based on the undisturbed blastocyst transcriptomes and identified time-lapse parameter correlated genes. These showed cross talk with identified embryo development gene functional modules, suggesting potential molecular mechanisms underlying the clinical predictive capabilities of embryo time-lapse morphokinetic parameters for subsequent live birth. This study suggests methodologies for assessing the impact of additional predictive correlates of value for optimal embryo development and understanding their mechanisms of action.