NMR studies of preimplantation embryo metabolism in human assisted reproductive techniques: a new biomarker for assessment of embryo implantation potential

Abstract

There has been growing interest in understanding energy metabolism in human embryos generated using assisted reproductive techniques (ART) for improving the overall success rate of the method. Using NMR spectroscopy as a noninvasive tool, we studied human embryo metabolism to identify specific biomarkers to assess the quality of embryos for their implantation potential. The study was based on estimation of pyruvate, lactate and alanine levels in the growth medium, ISM1, used in the culture of embryos. An NMR study involving 127 embryos from 48 couples revealed that embryos transferred on Day 3 (after 72 h in vitro culture) with successful implantation (pregnancy) exhibited significantly (p < 10(-5) ) lower pyruvate/alanine ratios compared to those that failed to implant. Lactate levels in media were similar for all embryos. This implies that in addition to lactate production, successfully implanted embryos use pyruvate to produce alanine and other cellular functions. While pyruvate and alanine individually have been used as biomarkers, the present study highlights the potential of combining them to provide a single parameter that correlates strongly with implantation potential.

1H NMR based profiling of spent culture media cannot predict success of implantation for day 3 human embryos

“…In particular, our findings are contrary to the study of Seli et al, [26] and to the study of Pudakalakatti et al [18] where a positive correlation was found between implantation and NMR profiling. The reason for the difference is unclear.…”

“…Our study contrast several publications that showed a correlation between specific metabolic profiles of embryo spent culture media and successful implantation [18,[25][26][27][28]31,33]; however, our findings are consistent with the results from two recent randomized controlled trials [11,31,33] showing no improvement in pregnancy outcome when media profiling was added to the conventional embryo selection protocol. In particular, our findings are contrary to the study of Seli et al, [26] and to the study of Pudakalakatti et al [18] where a positive correlation was found between implantation and NMR profiling.…”

“…However, pyruvate uptake in individual embryos differed widely, indicating that pyruvate uptake is a rather poor marker for embryo selection [5]. Pudakalakatti et al also analyzed the concentration of pyruvate in spent culture media; in addition, lactate and alanine were assessed in 57 embryos that implanted and 43 embryos that did not implant using NMR [18]. They found that embryos transferred on day 3 (after 72 h in vitro culture) with successful implantation exhibited significantly higher pyruvate uptake (not lower, as in the Conaghan study) and lower pyruvate/alanine ratios compared to those that failed to implant.…”

“…More recently the use of metabonomics of spent culture media has been studied by several groups. In particular, profiling using Raman, near-infrared spectroscopy (NIR) [25,28,32] or proton nuclear magnetic resonance spectroscopy ( 1 H NMR) [18,26] have been proposed to predict implantability. However, none of these techniques has yet been validated for clinical application [17,21] and two randomized control trials using Near Infrared (NIR) technology have recently failed to find a beneficial effect [11,31,33].…”

Selecting a Single Embryo for Transfer after In-vitro Fertilization: A Translational Medicine Perspective

“…This can be a powerful means of assessing embryos that are viable from those that are not in the future. There are also growing evidence that metabolic profiles of spent embryo culture media differ between embryos that implant and those that fail to implant and may be used to predict reproductive potential [18][19][20][21]. Technologies that assess omic profiles are available, the problem is that they are commonly applied to assess individual pathway.…”