Project Summary/Abstract
We propose studies to evaluate the direct impact of preimplantation embryo manipulation on the metabolism of
embryos and tissues. Because embryo manipulation is routinely used in the context of Assisted Reproductive
Technologies (ART) to treat patients with infertility, these goals have wide clinical implications. In fact, more
than 8 million children have been conceived by the technologies and more than 2.5 million in vitro fertilization
(IVF) cycles occur every year. Hence, there is great need to know if preimplantation embryo manipulation
induces subtle, but possibly long-lasting effects on the health of ART offspring.
The focus of this application is at the core of the PI’s expertise, as he has devoted most of his career to
understanding how ex-vivo embryo manipulation is associated with changes in the embryo (altered gene
expression, development, mitochondria function) and long-term maladaptive changes in the offspring (defects
in placentation, altered postnatal growth and ultimately altered glucose homeostasis).
While these results are important, multiple key questions remain unanswered. In particular, the molecular
mechanisms responsible to alter growth and metabolism in adults are unknown. For example, it is unclear if
metabolism is altered in embryos generated in vitro and if these metabolic alterations are maintained in adults
and responsible to cause abnormal glucose handling in adults generated by IVF. Importantly, the President's
Council on Bioethics and Congress urged the NICHD to determine whether these adverse outcomes are
specifically related to ART procedures.
Exciting novel preliminary data suggest that alteration of glycolysis and lactate metabolism are present in
embryos and possibly in adult generated by IVF. Based on preliminary data, objectives of this application are
to: 1) understand if alteration of glycolytic pathways exist in embryo who have undergone different degrees of
manipulation; discover the mechanisms leading to 2) metabolic alterations and 3) if specific epigenetic
changes exist; finally, 4) study if these alterations are maintained in adult mice conceived by IVF. Our central
hypothesis is that the ex vivo embryonic environment, deviating profoundly from the in vivo conditions (different
oxygen concentrations, altered energetic sources) cause increase in reactive oxygen species. Reparative
mechanisms will induce metabolic alterations and epigenetic changes. These molecular alterations will be
maintained in adult offspring resulting in altered glucose and lactate metabolism. Regarding expected
outcomes, we will: 1) determine what culture conditions produce greater or smaller change in glycolysis in
embryos, 2) discover the pathways responsible for these changes, 3) describe the specific epigenetic changes
induced by these alterations and finally 4) discover what metabolic pathways are altered in IVF offspring.
These datasets are expected to have an important impact because of the translational value to the fields of
developmental reprogramming, diabetes, obesity and for patients affected with infertility.