The mosaic embryo: what it means for the doctor and the patient.

INTRODUCTION: Mosaic embryos are embryos that on preimplantation genetic analysis are found to be composed of euploid and aneuploid cells. Although most of these embryos do not implant when transferred into the uterus following IVF treatment, some may implant and are capable of giving rise to babies. EVIDENCE ACQUISITION: There is currently an increasing number of reports of live births following the transfer of mosaic embryos. Compared to euploid, mosaic embryos have lower implantation rates and higher rates of miscarriage, and occasionally aneuploid component persists. However, their outcome is better than that obtained after the transfer of embryos consisting entirely of aneuploid cells. After implantation, the ability to develop into a full-term pregnancy is influenced by the amount and type of chromosomal mosaicism present in a mosaic embryo. Nowadays many experts in the reproductive field consider mosaic transfers as an option when no euploid embryos are available. Genetic counseling is an important part of educating patients about the likelihood of having a pregnancy with healthy baby but also on the risk that mosaicism could persist and result in liveborn with chromosomal abnormality. Each situation needs to be assessed on a case-by-case basis and counseled accordingly. EVIDENCE SYNTHESIS: So far, the transfers of 2155 mosaic embryos have been documented and 440 live births resulting in healthy babies have been reported. In addition, in the literature to date, there are 6 cases in which embryonic mosaicism persisted. CONCLUSIONS: In conclusion, the available data indicate that mosaic embryos have the potential to implant and develop into healthy babies, albeit with lower success rates than euploids. Further clinical outcomes should be collected to better establish a refined ranking of embryos to transfer.

PGT-M, a Useful Tool to Manage the Lynch Syndrome Transmission.

Lynch syndrome is one of the most common hereditary cancer sensitivity syndromes and is caused by autosomal-dominant germline mutations in DNA mismatch repair genes. In patients affected by this syndrome, pre-implantation genetic testing for monogenic disorders (PGT-M) could be the elective technique used to prevent the transmission of this hereditary syndrome to offspring. Notably, despite the severity of the condition, some authors have observed a markedly lower demand for PGT-M in these patients compared to those with other hereditary conditions. A 34-year-old woman with a medical history of Lynch syndrome associated with endometrial cancer came to the Villa Mafalda fertility center in Rome in order to conceive a healthy baby. In a pre-implantation genetic testing for aneuploidy (PGT-A) + PGT-M cycle, eight blastocysts were formed. Six out of eight blastocysts were affected by the same mother syndrome. One of the other two was aneuploid and the other one was a mosaic embryo, which resulted in a healthy pregnancy. The aim of this report is to emphasize the importance of a multidisciplinary approach to managing patients with this condition. In vitro fertilization (IVF), specifically PGT-M, is a tool that allow patients to conceive biological children with lower risk of inheriting the disease.

Two clinical case reports of embryonic mosaicism identified with PGT-A persisting during pregnancy as true fetal mosaicism.

The health risks associated with transferring embryos classified as mosaic by preimplantation genetic testing for aneuploidies (PGT-A) are currently unknown. Such embryos produce PGT-A results indicating the presence of both euploid and aneuploid cells and have historically been deselected from transfer and grouped with uniformly aneuploid embryos as 'abnormal'. In recent years, numerous groups have reported the intentional transfer of mosaic embryos in the absence of uniformly euploid embryos, largely observing births of seemingly healthy babies. However, it remains to be understood whether the embryonic mosaicism invariably becomes resolved during the ensuing pregnancy, or whether the placenta and/or fetal tissues retain aneuploid cells, and if so to what potential clinical effect. Here, we report two cases of mosaicism persisting from the embryonic stage to the established pregnancy. Case 1 involved an embryonic low-level segmental mosaic loss in Chromosome (Chr) 1, which was confirmed in amniocentesis as well as in brain tissue of the products of conception. This pregnancy was terminated due to the chromosomal pathologies associated with 1p36 deletion syndrome, such as severe intellectual disability. Case 2 involved a low-level mosaic Chr 21 trisomy, which was confirmed with chorionic villus sampling and amniocentesis. The ensuing pregnancy was terminated after ultrasound identification of severe abnormalities in the placenta and fetus. Together, these two cases should be taken into account for risk-benefit assessments of prospective mosaic embryo transfers.

Altered Follicular Fluid Metabolic Pattern Correlates with Female Infertility and Outcome Measures of In Vitro Fertilization.

Nearly 40-50% of infertility problems are estimated to be of female origin. Previous studies dedicated to the analysis of metabolites in follicular fluid (FF) produced contrasting results, although some valuable indexes capable to discriminate control groups (CTRL) from infertile females (IF) and correlate with outcome measures of assisted reproduction techniques were in some instances found. In this study, we analyzed in blind FF of 35 control subjects (CTRL = patients in which inability to obtain pregnancy was exclusively due to a male factor) and 145 IF (affected by: endometriosis, n = 19; polycystic ovary syndrome, n = 14; age-related reduced ovarian reserve, n = 58; reduced ovarian reserve, n = 29; unexplained infertility, n = 14; genetic infertility, n = 11) to determine concentrations of 55 water- and fat-soluble low molecular weight compounds (antioxidants, oxidative/nitrosative stress-related compounds, purines, pyrimidines, energy-related metabolites, and amino acids). Results evidenced that 27/55 of them had significantly different values in IF with respect to those measured in CTRL. The metabolic pattern of these potential biomarkers of infertility was cumulated (in both CTRL and IF) into a Biomarker Score index (incorporating the metabolic anomalies of FF), that fully discriminated CTRL (mean Biomarker Score value = 4.00 ± 2.30) from IF (mean Biomarker Score value = 14.88 ± 3.09, p < 0.001). The Biomarker Score values were significantly higher than those of CTRL in each of the six subgroups of IF. Posterior probability curves and ROC curve indicated that values of the Biomarker Score clustered CTRL and IF into two distinct groups, based on the individual FF metabolic profile. Furthermore, Biomarker Score values correlated with outcome measures of ovarian stimulation, in vitro fertilization, number and quality of blastocysts, clinical pregnancy, and healthy offspring. These results strongly suggest that the biochemical quality of FF deeply influences not only the effectiveness of IVF procedures but also the following embryonic development up to healthy newborns. The targeted metabolomic analysis of FF (using empowered Redox Energy Test) and the subsequent calculation of the Biomarker Score evidenced a set of 27 low molecular weight infertility biomarkers potentially useful in the laboratory managing of female infertility and to predict the success of assisted reproduction techniques.

Antioxidant-Based Therapies in Male Infertility: Do We Have Sufficient Evidence Supporting Their Effectiveness?

Under physiological conditions, reactive oxygen species (ROS) play pivotal roles in various processes of human spermatozoa. Indeed, semen requires the intervention of ROS to accomplish different stages of its maturation. However, ROS overproduction is a well-documented phenomenon occurring in the semen of infertile males, potentially causing permanent oxidative damages to a vast number of biological molecules (proteins, nucleic acids, polyunsaturated fatty acids of biological membrane lipids), negatively affecting the functionality and vitality of spermatozoa. ROS overproduction may concomitantly occur to the excess generation of reactive nitrogen species (RNS), leading to oxidative/nitrosative stress and frequently encountered in various human pathologies. Under different conditions of male infertility, very frequently accompanied by morpho-functional anomalies in the sperm analysis, several studies have provided evidence for clear biochemical signs of damages to biomolecules caused by oxidative/nitrosative stress. In the last decades, various studies aimed to verify whether antioxidant-based therapies may be beneficial to treat male infertility have been carried out. This review analyzed the results of the studies published during the last ten years on the administration of low-molecular-weight antioxidants to treat male infertility in order to establish whether there is a sufficient number of data to justify antioxidant administration to infertile males. An analysis of the literature showed that only 30 clinical studies tested the effects of the administration of low-molecular-weight antioxidants (administered as a single antioxidant or as a combination of different antioxidants with the addition of vitamins and/or micronutrients) to infertile males. Of these studies, only 33.3% included pregnancy and/or live birth rates as an outcome measure to determine the effects of the therapy. Of these studies, only 4 were case-control studies, and only 2 of them found improvement of the pregnancy rate in the group of antioxidant-treated patients. Additionally, of the 30 studies considered in this review, only 43.3% were case-control studies, 66.7% enrolled a number of patients higher than 40, and 40% carried out the administration of a single antioxidant. Therefore, it appears that further studies are needed to clearly define the usefulness of antioxidant-based therapies to treat male infertility.

Water- and Fat-Soluble Antioxidants in Human Seminal Plasma and Serum of Fertile Males.

Reactive oxygen species (ROS) are physiologically involved in functions like sperm maturation, capacitation and acrosome reaction, but their excess is involved in male infertility. Antioxidants in seminal plasma (SP) are an important factor balancing physiologic and harmful ROS activities. In this study, we determined and compared the full profiles of the water- and fat-soluble antioxidants in SP and serum of 15 healthy fertile subjects (ranging between the ages of 35 and 42 years). Ejaculates were obtained after 2⁻5 days of sexual abstinence. After liquefaction and withdrawal of an aliquot for the sperm count, samples were centrifuged to obtain SP. Thirty min after semen donation, a venous blood sample was collected from each subject. Donors with lower SP concentrations of ascorbic acid (n = 5) or α-tocopherol (n = 5) received a 4 week oral administration of either vitamin C (100 mg/day) or vitamin E (30 mg/day). They were then re-assayed to determine the SP and serum levels of ascorbic acid and α-tocopherol. SP and serum samples were properly processed and analyzed by HPLC methods suitable to determine water (ascorbic acid, glutathione (GSH) and uric acid) and fat-soluble (all-trans-retinoic acid, all-trans-retinol, α-tocopherol, carotenoids and coenzyme Q10) antioxidants. Data demonstrate that only ascorbic acid is higher in SP than in serum (SP/serum ratio = 4.97 ± 0.88). The other water-soluble antioxidants are equally distributed in the two fluids (GSH SP/serum ratio = 1.14 ± 0.34; uric acid SP/serum ratio = 0.82 ± 0.12). All fat-soluble antioxidants are about 10 times less concentrated in SP than in serum. In donors treated with vitamin C or vitamin E, ascorbic acid and α-tocopherol significantly increased in both fluids. However, the SP/serum ratio of ascorbic acid was 4.15 ± 0.45 before and 3.27 ± 0.39 after treatment, whilst those of α-tocopherol were 0.11 ± 0.03 before and 0.10 ± 0.02 after treatment. The results of this study, by showing the peculiar composition in water- and fat-soluble antioxidants SP, indicate that it is likely that still-unknown mechanisms allow ascorbic acid accumulation in SP against a concentration gradient. SP mainly relies its defenses on water- rather than fat-soluble antioxidants and on the mechanisms ensuring their transfer from serum.

Low-molecular weight compounds in human seminal plasma as potential biomarkers of male infertility.

STUDY QUESTION: Is the determination of antioxidants, oxidative/nitrosative stress-related compounds, purines, pyrimidines and energy-related metabolites in human seminal plasma of utility to evidence biomarkers related to male infertility? SUMMARY ANSWER: The determination of 26 metabolites in seminal plasma allowed to evidence that 21/26 of them are biomarkers of male infertility, as well as to calculate a cumulative index, named Biomarker Score, that fully discriminates fertile controls from infertile patients and partially differentiates infertile without from infertile with spermiogram anomalies. WHAT IS KNOWN ALREADY: Epidemiological studies indicated that a male factor is involved in ~50% of cases of pregnancy failure, with a significant percentage of infertile males having no alterations in the spermiogram. Further laboratory analyses of male infertility are mainly dedicated only to gross evaluations of oxidative stress or total antioxidant capacity. STUDY DESIGN, SIZE, DURATION: Seminal plasma of 48 fertile controls and 96 infertile patients (master group), were collected from September 2016 to February 2018. A second group of 44 infertile patients (validation group) was recruited in a second, independent centre from September 2017 to March 2018. Samples were analysed in blind using a 'Redox Energy Test' to determine various low-molecular weight compounds, with the aim of finding metabolic profiles and biomarkers related to male infertility. PARTICIPANTS/MATERIALS, SETTING, METHODS: In all seminal plasma, 26 water- and fat-soluble compounds (related to antioxidant defences, oxidative/nitrosative stress, purine, pyrimidine and energy metabolism) were analysed using high-performance liquid chromatographic methods. According to spermiogram, infertile patients of both groups were also categorized into normozoospermic (N, no anomalies in the spermiogram), or into the subgroup including all patients with anomalies in the spermiogram (asthenoteratooligozoospermic ATO + asthenozoospermic A + teratozoospermic T + oligozoospermic O). MAIN RESULTS AND THE ROLE OF CHANCE: In the master group, results indicated that 21/26 compounds assayed in seminal plasma of infertile males were significantly different from corresponding values determined in fertile controls. These 21 compounds constituted the male infertility biomarkers. Similar results were recorded in patients of the validation group. Using an index cumulating the biochemical seminal plasma anomalies (Biomarker Score), we found that fertile controls had mean Biomarker Score values of 2.01 ± 1.42, whilst infertile patients of the master and of the validation group had mean values of 12.27 ± 3.15 and of 11.41 ± 4.09, respectively (P < 0.001 compared to controls). The lack of statistical differences between the master and the validation groups, in both the metabolic profiles and the Biomarker Score values, allowed to pool patients into a single cohort of infertile males. The Biomarker Score values showed that fertile controls and infertile males clustered into two distinct groups. Infertile patients without (N, n = 42) or with (ATO + A + T + O, n = 98) spermiogram anomalies differed in some biomarkers (ascorbic acid, all-trans retinol, α-tocopherol, cytidine, uridine, guanine). These differences were reinforced by distribution frequencies and posterior probability curves of the Biomarker Score in the three groups. LIMITATIONS, REASONS FOR CAUTION: Results were obtained in relatively limited number of human seminal plasma samples. Using the 'Redox Energy Test' it was possible to associate specific metabolic profiles and values of the Biomarker Score to fertile controls or infertile males. However, it was not possible to evaluate whether the different anomalies of the spermiogram are associated with specific metabolic profiles and values of the Biomarker Score. WIDER IMPLICATIONS OF THE FINDINGS: The 'Redox Energy Test', coupled with the Biomarker Score that cumulates the biochemical characteristics of seminal plasma into a single index, evidenced a set of low-molecular weight biomarkers potentially useful in the laboratory management of male infertility. STUDY FUNDING/COMPETING INTEREST(S): The study was partly funded with research grants from the University of Catania. None of the authors have any conflicting interests to declare.