Risk of genetic and epigenetic alteration in children conceived following ART: Is it time to return to nature whenever possible?

Assisted reproductive technology may influence epigenetic signature as the procedures coincide with the extensive epigenetic modification occurring from fertilization to embryo implantation. However, it is still unclear to what extent ART alters the embryo epigenome. In vivo fertilization occurs in the fallopian tube, where a specific and natural environment enables the embryo's healthy development. During this dynamic period, major waves of epigenetic reprogramming, crucial for the normal fate of the embryo, take place. Over the past decade, concerns relating to the raised incidence of epigenetic anomalies and imprinting following ART have been raised by several authors. Epigenetic reprogramming is particularly susceptible to environmental conditions during the periconceptional period; therefore, unphysiological conditions, including ovarian stimulation, in vitro fertilization, embryo culture, cryopreservation of gametes and embryos, parental lifestyle, and underlying infertility, have the potential to contribute to epigenetic dysregulation independently or collectively. This review critically appraises the evidence relating to the association between ART and genetic and epigenetic modifications that may be transmitted to the offspring.

Chromosome Missegregation in Single Human Oocytes Is Related to the Age and Gene Expression Profile.

The growing trend for women to postpone childbearing has resulted in a dramatic increase in the incidence of aneuploid pregnancies. Despite the importance to human reproductive health, the events precipitating female age-related meiotic errors are poorly understood. To gain new insight into the molecular basis of age-related chromosome missegregation in human oocytes, we combined the transcriptome profiles of twenty single oocytes (derived from females divided into two groups according to age <35 and ≥35 years) with their chromosome status obtained by array comparative genomic hybridization (aCGH). Furthermore, we compared the transcription profile of the single oocyte with the surrounding cumulus cells (CCs). RNA-seq data showed differences in gene expression between young and old oocytes. Dysregulated genes play a role in important biological processes such as gene transcription regulation, cytoskeleton organization, pathways related to RNA maturation and translation. The comparison of the transcription profile of the oocyte and the corresponding CCs highlighted the differential expression of genes belonging to the G protein-coupled receptor superfamily. Finally, we detected the loss of a X chromosome in two oocytes derived from women belonging to the ≥35 years age group. These aneuploidies may be caused by the detriment of REEP4, an endoplasmic reticulum protein, in women aged ≥35 years. Here we gained new insight into the complex regulatory circuit between the oocyte and the surrounding CCs and uncovered a new putative molecular basis of age-related chromosome missegregation in human oocytes.

Is there a critical endometrioma size associated with reduced ovarian responsiveness in assisted reproduction techniques?

This study investigated the relationships between ovarian endometrioma size, ovarian responsiveness and the number of retrieved oocytes following ovarian stimulation. A prospective study was conducted in a public clinical assisted reproduction centre. A total of 64 infertile women with monolateral endometriomas undergoing IVF or intracytoplasmic sperm injection were included in the study. The total number of follicles, number of follicles ≥ 16 mm and number of oocytes retrieved of ovaries containing endometrioma and normal ovaries were compared. Multivariate linear regression was used to assess whether number of follicles and collected oocytes varied by endometrioma size, age, basal FSH concentration. Significantly lower numbers of follicles ≥ 16 mm (P = 0.024) and oocytes retrieved (P = 0.001) in the ovaries containing endometrioma were observed. In patients with endometriomas ≥ 30 mm, endometrioma size was the most influential contributor to the total number of follicles and oocytes retrieved. Ovarian endometriomas result in reduced response to ovarian stimulation, compared with the response of the contralateral normal ovary in the same individual. In case of endometriomas <30 mm, basal FSH concentration remains the most important prognostic factor for oocyte retrieval.

Air quality in the clinical embryology laboratory: a mini-review.

The scope of the clinical embryology laboratory has expanded over recent years. It now includes conventional in vitro fertilization (IVF) techniques and complex and time-demanding procedures like blastocyst culture, processing of surgically retrieved sperm, and trophectoderm biopsy for preimplantation genetic testing. These procedures require a stable culture environment in which ambient air quality might play a critical role. The existing data indicate that both particulate matter and chemical pollution adversely affect IVF results, with low levels for better outcomes. As a result, IVF clinics have invested in air cleaning technologies with variable efficiency to remove particulates and volatile organic compounds. However, specific regulatory frameworks mandating air quality control are limited, as are evidence-based guidelines for the best air quality control practices in the embryology laboratory. In this review, we describe the principles and existing solutions for improving air quality and summarize the clinical evidence concerning air quality control in the embryology laboratory. In addition, we discuss the gaps in knowledge that could guide future research to improve clinical outcomes.

A 46,XX SRY-negative man with complete virilization and infertility as the main anomaly.

OBJECTIVE: To report a case of a 46,XX SRY-negative man with a male phenotype and azoospermia. DESIGN: Case report. SETTING: Molecular and Cytogenetic Unit in a University Hospital. PATIENT(S): A 35-year-old man with complete masculinization who referred to our institution because of a history of several years of infertility. INTERVENTION(S): Lymphocytic karyotype and genetic counseling. MAIN OUTCOME MEASURE(S): Peripheral blood metaphases were analyzed by standard G-banding and Q-banding. Fluorescent in situ hybridization (FISH) and polymerase chain reaction (PCR) analyses were performed. RESULT(S): Semen analysis showed azoospermia. Chromosome analysis revealed a 46,XX karyotype; molecular and cytogenetic analyses excluded the presence of SRY (the sex-determining region of the Y chromosome) gene. CONCLUSION(S): This case is one of the rare patients reported in the literature in whom testicular differentiation and a complete virilization in a 46,XX chromosomal constitution does not account for a translocation of the SRY gene to the X chromosome or to the autosomes. This finding suggests that other genes downstream from SRY, not yet identified, play an important role in sex determination.

Molecular and cytogenetic characterization of a structural rearrangement of the Y chromosome in an azoospermic man.

OBJECTIVE: To better define an abnormal karyotype found in a male with primary infertility. DESIGN: Case report. SETTING: Molecular and cytogenetics unit in a university-affiliated hospital. PATIENT(S): A 41-year-old, azoospermic, but otherwise healthy male. INTERVENTION(S): Lymphocytic karyotype and genetic counseling. MAIN OUTCOME MEASURE(S): Metaphases were studied by standard G- and Q-banding, followed by fluorescence in situ hybridization (FISH) and polymerase chain reaction to analyze specific Y chromosome regions. RESULT(S): Chromosomal analysis and FISH allowed us to define the propositus's karyotype as 45,X/46,X,idic(Yp)/46,XY (71%, 26%, and 3% of analyzed metaphases, respectively). Molecular analysis of azoospermic factor (AZF) regions showed deletion of AZFb and AZFc. CONCLUSION(S): A 45,X/46,X,idic(Yp) mosaicism is associated with a very broad spectrum of phenotypes, including patients with Ullrich-Turner syndrome, patients with various degrees of genital ambiguity, or normal males. In the presence of a normal masculinization in otherwise healthy males azoospermia is a distinct feature that can be explained by partial deletion of AZF regions.