Is there 'glue' for embryos? EmbryoGlue

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L'EmbryoGlue is a embryo transfer medium used in medically assisted procreation (MAP) techniques, particularly in in vitro fertilisation (IVF/ICSI). It was developed with the aim of improving embryo implantation, one of the main factors limiting the success of PMA procedures. The product features a high concentration of hyaluronic acid (HA), a molecule naturally present in the endometrium and uterine fluids during the implantation window. In addition to hyaluronic acid in high concentration, it contains recombinant human albumin, electrolytes, amino acids and carbohydrates in physiological concentrations. There are no proteins of animal origin inside. This composition aims to reproduce the uterine microenvironment as faithfully as possible.

The way EmbryoGlue performs its action is mainly attributed to hyaluronic acid, which acts through several mechanisms Increasing embryo-endometrium adhesiveness, as hyaluronic acid interacts with CD44 receptors expressed by both the embryo and the endometrium, facilitating initial anchorage; Improving the viscosity of the medium, higher viscosity can reduce the dispersion of the embryo after transfer, favouring retention in the uterine cavity, as it is denser it acts limiting the random movements of the embryo in the uterus after transfer by helping it to remain in contact with the uterine wall; and finally by providing biological support to the embryo, thanks to hyaluronic acid's role in cell proliferation, migration and protection from oxidative stress.

This type of transfer medium with a high concentration of hyaluronic acid is proposed in different clinical contexts such as in patients with repeated implantation failure (RIF), in embryo transfers at the blastocyst stage, in PMA cycles with poor prognosis or in single transfers to increase the probability of success. Numerous clinical studies and meta-analyses have evaluated the efficacy of EmbryoGlue suggesting evidence for a significant increase in implantation and clinical pregnancy rates, an effect more evident in selected subgroups (e.g. RIF) and pointing out no demonstrated increase in congenital abnormalities or neonatal adverse events. However, some studies report mixed results, indicating that the benefit may depend on factors such as maternal age, embryo quality and laboratory protocol. In general, it should be emphasised that this technique of using an embryo transfer medium should not replace proper embryo selection or endometrial evaluation, which remain the main objectives for a higher probability of success.

In conclusion, EmbryoGlue represents an evolution in embryo transfer media, based on solid biological grounds. Scientific evidence supports a potential improvement of reproductive outcomes, especially in selected patients. However, further randomised studies are needed to define more precisely which groups benefit most.

 

References

1. Bontekoe S. et al. High concentration hyaluronan in embryo transfer media for assisted reproductive technologies.Cochrane Database of Systematic Reviews, 2014.
2. Simon A. et al. Hyaluronic acid can successfully replace albumin as the sole macromolecule in human embryo transfer media.Fertility and Sterility, 2003.
3. Hazlett W.D. et al. Effect of EmbryoGlue on implantation and pregnancy rates.Journal of Assisted Reproduction and Genetics, 2008.
4. EmbryoGlue - Scientific background and clinical documentation.