Symposium: innovative techniques in human embryo viability assessment. Non-invasive assessment of embryo viability by metabolomic profiling of culture media ('metabolomics').

Increasing the efficiency of the IVF procedure by improving pregnancy/implantation rates and at the same time lowering (or avoiding) the risks of multiple gestations are the primary goals of the current assisted reproductive technology. These aims require a much improved gamete/embryo testing and selection procedure, which, using the current approach of microscopy-based morphology evaluation is unlikely to be achieved. Therefore, alternative or additional, non-invasive techniques have been proposed which may be able to detect alterations of the culture environment surrounding gametes/embryos reflective of the (patho-)physiological processes. One of the most recently applied approaches is to measure metabolomic changes in the culture medium of embryos and oocytes ('exometabolomics'). Initial studies have demonstrated that different types of spectrophotometric tests, including Raman and near-infrared (NIR) techniques, are similarly well capable of detecting specific changes of the 'secretome' (exometabolome). These studies have also demonstrated that metabolomic measurements correlate well with embryo development and morphology assessment. Furthermore, viability index on oocytes/embryos established by metabolomic tests may be a stronger predictor for implantation potential than traditional morphological assessment. Although the results of these initial investigations are promising, further prospective studies are required to define clearly the potential benefits and most relevant applications of this novel non-invasive technology in the field of assisted reproduction.