Rescuing monopronucleated-derived human blastocysts: a model to study chromosomal topography and fingerprinting.

OBJECTIVE: To quantify the percentage of monopronuclear-derived blastocysts (MNBs) that are potentially useful for reproductive purposes using classic and state-of-the-art chromosome analysis approaches, and to study chromosomal distribution in the inner cell mass (ICM) and trophectoderm (TE) for intertissue/intratissue concordance comparison. DESIGN: Prospective experimental study. SETTING: Single-center in vitro fertilization clinic and reproductive genetics laboratory. PATIENT(S): A total of 1,128 monopronuclear zygotes were obtained between June 2016 and December 2018. INTERVENTION(S): MNBs were whole-fixed or biopsied to obtain a portion of ICM and 2 TE portions (TE1 and TE2) and were subsequently analyzed by fluorescence in situ hybridization, new whole-genome sequencing, and fingerprinting by single-nucleotide polymorphism array-based techniques (a-SNP). MAIN OUTCOME MEASURE(S): We assessed MNB rate, ploidy rate, and chromosomal constitution by new whole-genome sequencing, and parental composition by comparative a-SNP, performed in a "trio"-format (embryo/parents). The 24-chromosome distribution was compared between the TE and the ICM and within the TE. RESULT(S): A total of 18.4% of monopronuclear zygotes progressed to blastocysts; 77.6% of MNBs were diploid; 20% of MNBs were male and euploid, which might be reproductively useful. Seventy-five percent of MNBs were biparental and half of them were euploid, indicating that 40% might be reproductively useful. Intratissue concordance (TE1/TE2) was established for 93.3% and 73.3% for chromosome matching. Intertissue concordance (TE/ICM) was established for 78.8%, but 57.6% for chromosome matching. When segmental aneuploidy was not considered, intratissue concordance and chromosome matching increased to 100% and 80%, respectively, and intertissue concordance and chromosome matching increased to 84.8% and 75.8%, respectively. CONCLUSION(S): The a-SNP-trio strategy provides information about ploidy, euploidy, and parental origin in a single biopsy. This approach enabled us to identify 40% of MNBs with reproductive potential, which can have a significant effect in the clinical setting. Additionally, segmental aneuploidy is relevant for mismatched preimplantation genetic testing of aneuploidies, both within and between MNB tissues. Repeat biopsy might clarify whether segmental aneuploidy is a prone genetic character.

Obstetric and perinatal outcomes of pregnancies conceived with embryos cultured in a time-lapse monitoring system.

OBJECTIVE: To compare obstetric and perinatal outcomes of singleton pregnancies resulting from embryos incubated in a time-lapse system (TLS) with those of embryos grown in standard IVF incubators (SI). DESIGN: Retrospective description of a cohort of patients who conceived during a randomized, controlled trial. SETTING: Private university-affiliated IVF center. PATIENT(S): Of 856 randomized patients, 378 gave birth to a live-born infant: 216 of the deliveries originated from embryos incubated in TLS, and 162 deliveries were from embryos cultured in SI. INTERVENTION(S): Embryo incubation and selection in TLS. MAIN OUTCOME MEASURE(S): Delivery and neonatal outcomes. RESULT(S): No significant differences were observed in the baseline characteristics of the study population. The delivery rate was 49.3% (TLS) vs. 40.0% (SI), and multiple deliveries were higher in the TLS group: 31.0% (67 of 216) vs. 24.7% (40 of 162) in the SI group. When singleton pregnancies were analyzed no differences were found between the two groups in the rate of obstetric problems with respect to weeks at delivery: 38.8 (95% confidence interval [CI] 38.4-39.1) (TLS) vs. 39.5 (95% CI 38.0-39.9) (SI); preterm births (<37 weeks): 10.7% (TLS) vs. 12.3% (SI); and very preterm births (<34 weeks): 2.9% (TLS) vs. 3.3% (SI). No statistical differences were found in neonatal outcomes such as birth weight: 3,163 g (95% CI 3,035-3,292 g) (TLS) vs. 3,074 (95% CI 2,913-3,236) (SI); low birth weight (<2,500 g): 12.8% (TLS) vs. 12.3% (SI); very low birth weight (<1,500 g): 2.0% (TLS) vs. 2.4% (SI); or height: 50.3 cm (95% CI 49.6-50.9 cm) (TLS) vs. 49.7 (95% CI 48.9-50.4 cm) (SI). No major malformations or perinatal mortality were found in either of the two groups. CONCLUSION(S): No detrimental effects were observed in obstetric and perinatal outcomes when a time-lapse incubator was used rather than a more widely used conventional incubator. As far as we know this is the first report from a randomized study of the neonatal outcomes of time-lapse monitoring. Our results suggest that this technology is an effective and safe alternative for embryo incubation, though trials of larger numbers of patients are required to further confirm our conclusions. CLINICAL TRIAL REGISTRATION NUMBER: NCT01549262.

Docosahexaenoic acid prevents apoptosis of retina photoreceptors by activating the ERK/MAPK pathway.

Identifying the trophic factors for retina photoreceptors and the intracellular pathways activated to promote cell survival is crucial for treating retina neurodegenerative diseases. Docosahexaenoic acid (DHA), the major retinal polyunsaturated fatty acid, prevents photoreceptor apoptosis during early development in vitro, and upon oxidative stress. However, the signaling mechanisms activated by DHA are still unclear. We investigated whether the extracellular signal regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) or the phosphatidylinositol-3-kinase (PI3K) pathway participated in DHA protection. 1,4-Diamino-2,3-dicyano-1,4-bis(2-aminophynyltio) butadiene (U0126), a specific MEK inhibitor, completely blocked the DHA anti-apoptotic effect. DHA rapidly increased ERK phosphorylation in photoreceptors, whereas U0126 blocked this increase. U0126 hindered DHA prevention of mitochondrial depolarization, and blocked the DHA-induced increase in opsin expression. On the contrary, PI3K inhibitors did not diminish the DHA protective effect. DHA promoted the early expression of Bcl-2, decreased Bax expression and reduced caspase-3 activation in photoreceptors. These results suggest that DHA exclusively activates the ERK/MAPK pathway to promote photoreceptor survival during early development in vitro and upon oxidative stress. This leads to the regulation of Bcl-2 and Bax expression, thus preserving mitochondrial membrane potential and inhibiting caspase activation. Hence, DHA, a lipid trophic factor, promotes photoreceptor survival and differentiation by activating the same signaling pathways triggered by peptidic trophic factors.