[Impact of SARS-CoV-2 on fertility, gametes' quality and Assisted Reproduction Technology]

Le contexte actuel de pandémie conduit à s’interroger sur les conséquences de la COVID-19 en Assistance médicale à la procréation (AMP). En effet, suite aux premières recommandations de l’Agence de la biomédecine en mars 2020, les centres d’AMP ont suspendu leurs activités. La reprise progressive des tentatives en mai 2020 s’est accompagnée de nombreux questionnements, concernant les effets directs et indirects du SARS-CoV-2 sur la qualité des gamètes, la gamétogenèse, la fertilité, la grossesse et la santé néonatale. L’objectif de cette revue de la littérature est de synthétiser les données disponibles, pour informer les patient(e)s pris(es) en charge et adapter les pratiques d’AMP en cette période de la COVID-19. La plupart des études récentes se basent sur l’évaluation des effets du syndrome infectieux, sur l’analyse des facteurs hormonaux, et sur l’expression des protéines d’entrée virale (ACE2 et TMPRSS2) au niveau des cellules impliquées dans la gamétogenèse pour évaluer les répercussions de la COVID-19. La transmission materno-fœtale du SARS-CoV-2 n’a pas pu être démontrée à ce jour, mais l’infection néonatale reste possible. Néanmoins, les hommes seraient plus à risque d’être infectés par le SARS-CoV-2, d’être symptomatiques et la spermatogenèse est vraisemblablement affectée. La présence du virus dans le sperme est un évènement rare, mais l’ensemble de ces paramètres sont à prendre en compte dans la prise en charge des couples en AMP. Cependant, aucune conséquence sur la qualité des gamètes féminins n’a été mise en évidence jusqu’à présent.

[Importance of the determination of MTHFR SNPs (Methylene Tetrahydrofolate Reductase Single Nucleotide Polymorphisms) in couple infertility]

OBJECTIVE

MTHFR SNPs (Methylene Tetrahydrofolate reductase Single Nucleotide polymorphisms) are biochemical modifications decreasing the capacity to form 5 MTHF 5 methyltetrahydrofolate (5MTHF). Their presence reduces the capacity of the One Carbon cycle, and so the regeneration of Homocysteine (Hcy) and in fine strongly perturbs all the methylation processes. As methylation processes are major regulators in gametogenesis and embryogenesis. We have determined the prevalence of the 2 most important SNPs A1298C and C677T in our population of patients consulting for infertility.

METHODS

Determination of the MTHFR SNPs A1298C and C677T, by hybridization using the LAMP Human MTHFR mutation KITs.

RESULTS

Only 15.8% of our patients (861) do not carry any SNP (WT wid type). Close to 20% of the patients are homozygotes for one mutation or the other. A total of 19.7% are composite heterozygous. A total of 43% of our population is considered "at risk", based on observations collected for the repeat miscarriages.

CONCLUSIONS

Determination of the 2 major MTHFR SNPs is not a "first row" choice, but it must not be neglected and should be carried out in case of repeat ART failures and repeat miscarriages. Some simple therapeutic options can be proposed: they are based on the use of 5MTHF (5MethyleneTetraHydroFolate) the compound downstream the MTHFR.

[Impact of air quality on practices and results in the IVF laboratory]

The concept of Air Quality often refers to particulate and microbiological contamination of ambiant air. European Directive 2006/86/CE encompass the IVF process and specify a class A air quality for manipulation of tissue and cells, in a class D environment (A over D rule). Recognizing the paramount importance of ensuring the highest microbiological and particulate safety in the IVF laboratory, it is equally important to take into account practicability issues and the financial burden of these recommendations, as well as the utter need to protect gametes and embryo viability during their IVF journey. The usefulness of such stringent recommendations may also be questionned given the absence of published cases of airborne contaminations and related patients infections after embryo transfer. The European directive stems from pharmaceutical standards and were not specifically designed for human IVF. Gametes and embryos are indeed extremely sensitive to physical and chemical stress and require strict temperature, osmolarity and pH control, as well as an absence of chemical contamination during manipulation and culture. These conditions are hardly obtained when using laminar flow hoods. Following concerns raised by many experts in the field, exceptions to the A over D rule were added in the 2006/86/CE Directives. This narrative review discusses all these aspects in a critical way and compare scientific and legal requirements applying to IVF practices in different regions of the world.