From glass to life: a commentary on the assessment of the reproductive potential of cryopreserved human oocytes

© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Oocyte cryopreservation is one of the more recently established methods of assisted reproduction technologies (ART). Vitrifcation procedures have helped to overcome most technical difculties enabling better oocyte survival after warming. There are diferent indications for oocyte cryopreservation. The technology can be used if the partner fails to produce sperm for an IVF treatment on the day of oocyte collection. For patients at risk of ovarian hyperstimulation syndrome (OHSS), we could also opt not only for “freeze-all embryos” but possibly also for “freeze-all oocytes.” Also, women who may have no partner or may lose their fertility potential due to surgery, chemotherapy, radiotherapy, autoimmune diseases, medical conditions causing ovarian insuffciency, or hematopoietic stem cell transplantation could store their oocytes for future use. Planned oocyte cryopreservation can also be used as a tool to help mitigate age-related fertility decline regardless of whether a patient is partnered. All such procedures raise questions both to patients and healthcare professionals: Can we predict the chance for the parenthood from one medically assisted reproduction (MAR) cycle with cryopreserved oocytes? What is the minimal number of cryopreserved oocytes needed to have a reasonable likelihood of success? Is there an upper age limit for women to store their oocytes?The paper is a part of research programme P3-0327 funded by the Slovenian Research Agency.info:eu-repo/semantics/publishedVersio

Genetic Dissection of the AZF Regions of the Human Y Chromosome: Thriller or Filler for Male (In)fertility?

The azoospermia factor (AZF) regions consist of three genetic domains in the long arm of the human Y chromosome referred to as AZFa, AZFb and AZFc. These are of importance for male fertility since they are home to genes required for spermatogenesis. In this paper a comprehensive analysis of AZF structure and gene content will be undertaken. Particular care will be given to the molecular mechanisms underlying the spermatogenic impairment phenotypes associated to AZF deletions. Analysis of the 14 different AZF genes or gene families argues for the existence of functional asymmetries between the determinants; while some are prominent players in spermatogenesis, others seem to modulate more subtly the program. In this regard, evidence supporting the notion that DDX3Y, KDM5D, RBMY1A1, DAZ, and CDY represent key AZF spermatogenic determinants will be discussed

Characterizing partial AZFc deletions of the Y chromosome with amplicon-specific sequence markers

BACKGROUND: The AZFc region of the human Y chromosome is a highly recombinogenic locus containing multi-copy male fertility genes located in repeated DNA blocks (amplicons). These AZFc gene families exhibit slight sequence variations between copies which are considered to have functional relevance. Yet, partial AZFc deletions yield phenotypes ranging from normospermia to azoospermia, thwarting definite conclusions on their real impact on fertility. RESULTS: The amplicon content of partial AZFc deletion products was characterized with novel amplicon-specific sequence markers. Data indicate that partial AZFc deletions are a male infertility risk [odds ratio: 5.6 (95% CI: 1.6–30.1)] and although high diversity of partial deletion products and sequence conversion profiles were recorded, the AZFc marker profiles detected in fertile men were also observed in infertile men. Additionally, the assessment of rearrangement recurrence by Y-lineage analysis indicated that while partial AZFc deletions occurred in highly diverse samples, haplotype diversity was minimal in fertile men sharing identical marker profiles. CONCLUSION: Although partial AZFc deletion products are highly heterogeneous in terms of amplicon content, this plasticity is not sufficient to account for the observed phenotypical variance. The lack of causative association between the deletion of specific gene copies and infertility suggests that AZFc gene content might be part of a multifactorial network, with Y-lineage evolution emerging as a possible phenotype modulator

The time is ripe for oocyte in vitro maturation

© The Author(s) 2021.When it comes to welcome transitions 2021 seems to have started on a promising note. From the ushering in of COVID-19 vaccination programs to a renewed appreciation of evidence-based policy in many countries progress manifested itself in swift and emphatic manners. The same can be said of the field of assisted reproduction techniques (ART) home to a recent practice committee document on oocyte in vitro maturation (IVM) [1]. In this landmark document the practice committees of the American Society for Reproductive Medicine (ASRM) the Society of Reproductive Biologists and Technologists and the Society for Assisted Reproductive Technology (SART) present a considerable (and compelling) body of published evidence supporting the conclusion that IVM should no longer be considered an experimental technique.Study partially supported by a Fundação para a Ciência e a Tecnologia grant (PTDC/MEC-AND/30221/2017).info:eu-repo/semantics/publishedVersio

Electre Tri-C, a multiple criteria decision aiding sorting model applied to assisted reproduction

International audienceObjective The aim of this paper is to apply an informatics tool for dealing with a medical decision aiding problem to help infertile couples to become parents, when using assisted reproduction. Methods A multiple criteria decision aiding method for sorting or ordinal classification problems, called Electre Tri-C, was chosen in order to assign each couple to an embryo-transfer category. The set of categories puts in evidence a way for increasing the single pregnancy rate, while minimizing multiple pregnancies. The decision aiding sorting model was co-constructed through an interaction process between the decision aiding analysts and the medical experts. Results According to the sample used in this study, the Electre Tri-C method provides a unique category in 86% of the cases and it achieves a sorting accuracy of 61%. Retrospectively, the medical experts do agree that some of their judgments concerning the number of embryos to transfer back to the uterus of the woman could be different according to these results. The current ART methodology achieves a single pregnancy rate of 47% and a twin pregnancy rate of 14%. Thus, this informatics tools may play an important role for supporting ART medical decisions, aiming to increase the single pregnancy rate, while minimizing multiple pregnancies. Limitations Building the set of criteria comprises a part of arbitrariness and imperfect knowledge, which require time and expertise to be refined. Among them, three criteria are modeled by means of a holistic classification procedure by the medical experts

Incorrect DNA methylation of the DAZL promoter CpG island associates with defective human sperm

Background: Successful gametogenesis requires the establishment of an appropriate epigenetic state in developing germ cells. Nevertheless, an association between abnormal spermatogenesis and epigenetic disturbances in germline-specific genes remains to be demonstrated. Methods: In this study, the DNA methylation pattern of the promoter CpG island (CGI) of two germline regulator genes—DAZL and DAZ, was characterized by bisulphite genomic sequencing in quality-fractioned ejaculated sperm populations from normozoospermic (NZ) and oligoasthenoteratozoospermic (OAT) men. Results: OAT patients display increased methylation defects in the DAZL promoter CGI when compared with NZ controls. Such differences are recorded when analyzing sperm fractions enriched either in normal or defective germ cells (P , 0.001 in both cases). Significant differences in DNA methylation profiles are also observable when comparing the qualitatively distinct germ cell fractions inside the NZ and OAT groups (P ¼ 0.003 and P ¼ 0.007, respectively). Contrastingly, the unmethylation pattern of the DAZ promoter CGI remains correctly established in all experimental groups. Conclusions: An association between disrupted DNA methylation of a key spermatogenesis gene and abnormal human sperm is described here for the first time. These results suggest that incorrect epigenetic marks in germline genes may be correlated with male gametogenic defects.Fundação para a Ciência e a Tecnologia (#SFRH/BD/16662/2004 to P.N.-C.) and Centro de Investigação em Genética Molecular Human