Despite its wide-spread use, the success rate of assisted reproductive technologies including in vitro fertilization is less than 20%. Most human embryos are mosaic for chromosome abnormalities: containing cells that are euploid (normal) and aneuploid (incorrect number of chromosomes). Currently, a cell biopsy is used in IVF clinics to diagnose aneuploidy in the embryo but this does not provide a diagnosis of how many cells are aneuploid in the entire embryo. Hence, the development of a non-invasive tool to determine the proportion of aneuploid cells would likely improve IVF success. Aneuploidy in human embryos leads to altered metabolism. The co-factors utilized in cellular metabolism are autofluorescent and can be used to predict the metabolic state of cells. Here we used hyperspectral imaging to noninvasively assess intracellular fluorophores and thus metabolism. In this study, we utilized a powerful model of embryo aneuploidy where we generate mouse embryos with differing ratios of euploid:aneuploid cells. We also used primary human fibroblast cells with known aneuploidies to make comparison with euploid cells. Hyperspectral imaging of 1:3 chimeric embryos showed a distinct spectral profile compare to the control/normal embryos. The abundance of FAD in the inner cell mass (cells that form the fetus) of euploid and aneuploid blastocysts was strikingly different. For human cell lines, we were able to clearly distinguish between euploid and aneuploid with different karyotypes. These data show hyperspectral imaging is able to distinguish cells based on their ploidy status making it a promising tool in assessing embryo mosaicism.
Despite its wide-spread use, the success rate of assisted reproductive technologies including IVF is less than 20% in Australia/New Zealand. Most early human embryos are mosaic for chromosome abnormalities, containing a proportion of normal and abnormal cells. The most common chromosomal abnormality is aneuploidy: incorrect number of chromosomes. This form of mosaicism is thought account for early pregnancy loss in IVF. Current single cell biopsies of embryos are not diagnostic for the proportion of cells that are aneuploid (degree of heterogeneity/mosaicism). Thus, development of a non-invasive tool to determine the proportion of aneuploid cells facilitating segregation of embryos with a low percentage of aneuploid cells would likely improve IVF success rates. In other cells, including cancer cells, aneuploidy results in altered cellular metabolism. In this study we utilised hyperspectral imaging as a means of non-invasively measuring cellular metabolism in the early embryo. We utilised a mouse model where we manipulated the ratio of aneuploid:normal cells. Aneuploid embryos were generated by treatment during division from 4 to 8 cells using a reversible spindle assembly check point inhibitor, reversine. Eight-cell aneuploid embryos were dissociated and joined with control/normal cells to generate 1:1 aneuploid:normal chimeras. Hyperspectral imaging of 1:1 chimeric embryos had a distinct spectral profile that varied dramatically from the control/normal embryos. Interestingly, entirely aneuploid embryos showed a spectral profile dissimilar from both normal and chimeric embryos. These data show hyperspectral imaging is capable of distinguishing between embryos with varying degrees of aneuploidy making it a promising tool in assessing embryo health.