F&S science最新文献

Detection of chromosomal aneuploidies and monogenic disorders in preimplantation embryos is essential for selecting the best embryo for transfer during in vitro fertilization to achieve a healthy pregnancy. Preimplantation genetic testing (PGT) is typically performed on preimplantation embryos to select a genetically normal embryo for transfer. A trophectoderm biopsy is necessary for PGT; this is an invasive procedure to the embryo that requires specialized equipment and highly trained embryologists, resulting in high costs associated with in vitro fertilization treatment. Moreover, the biopsy procedure may increase the likelihood of developing pregnancy complications, such as preeclampsia and hypertensive disorders. Therefore, there is a need for noninvasive embryo screening strategies. The presence of cell-free deoxyribonucleic acid in the embryo culture medium presents an opportunity to screen for genetic abnormalities. Cell-free deoxyribonucleic acid is released by embryos in the latter stages of preimplantation development, and its analysis has been proposed as a noninvasive approach for PGT. Here, we review studies reporting the concordance rates between cell-free deoxyribonucleic acid and trophectoderm biopsies, or whole blastocysts, in couples undergoing PGT. Noninvasive PGT results are promising for aneuploidy detection, with some early evidence of successful clinical application. Further research is required to explore its application for the detection of structural rearrangements and monogenic disorders.

Objective

To determine the relationship between the levels of cumulus cell (CC) hemoglobin messenger ribonucleic acid (mRNA) and the developmental potential of the associated oocyte and whether hemoglobin protects the CCs from oxidative stress–induced apoptosis.

Design

Laboratory-based study.

Setting

University laboratory and university-affiliated in vitro fertilization center.

Patient(s)

Cumulus cells from the oocytes of patients who underwent in vitro fertilization with intracytoplasmic sperm injection with and without preimplantation genetic testing between 2018 and 2020.

Intervention(s)

Studies on individual and pooled CCs collected at the time of oocyte retrieval or cultured under 20% or 5% O₂.

Main Outcome Measure(s)

Quantitative polymerase chain reaction analysis of individual and pooled patient CC samples were used to monitor the hemoglobin mRNA levels. Reverse transcription-polymerase chain reaction arrays were used to assess genes that regulate oxidative stress in CCs associated with aneuploid and euploid blastocysts. Studies were conducted to assess the effect of oxidative stress on the rate of apoptosis, level of reactive oxygen species, and gene expression in CCs in vitro.

Result(s)

Compared with CCs associated with arrested and aneuploid blastocysts, the mRNA levels encoding the alpha and beta chains of hemoglobin increased by 2.9- and 2.3-fold in CCs associated with euploid blastocysts, respectively. The mRNA levels encoding the alpha and beta chains of hemoglobin also increased by 3.8- and 4.5-fold in CCs cultured under 5% O₂ vs. 20% O₂, respectively, and multiple regulators of oxidative stress were overexpressed in cells cultured under 20% O₂ compared with those under 5% O₂. However, the rate of apoptosis and amount of mitochondrial reactive oxidative species increased by 1.25-fold in CCs cultured under 20% O₂ compared with those under 5% O₂. Variable amounts of the alpha and beta chains of hemoglobin were also detected within the zona pellucida and oocytes.

Conclusion(s)

Higher levels of nonerythroid hemoglobin in CCs are associated with oocytes that result in euploid blastocysts. Hemoglobin may protect CCs from oxidative stress–induced apoptosis, which may enhance cumulus-oocyte interactions. Moreover, CC-derived hemoglobin may be transferred to the oocytes and protect it from the adverse effects of oxidative stress that occurs in vivo and in vitro.

Objective

To gain an understanding of the potential role of endoplasmic reticulum (ER) stress in the endometrial compartment during early pregnancy, a highly understudied area.

Design

This study examined the regulation of interferon-β (IFNβ) in response to ER stress in human decidualized and nondecidualized endometrial cells (human endometrial stromal cells [HESCs]) in vitro. In vivo, we examined ER stress and the IFNβ levels locally in the mouse endometrium before and after implantation at embryonic day (E)1, E3, and E6.

Setting

The study was performed in a reproductive sciences laboratory for Human Growth and Development.

Patient(s)

None.

Intervention(s)

None.

Main Outcome Measure(s)

Quantitative polymerase chain reaction, Western blotting, and immunohistochemical analysis allowed us to test the action of endogenous ER stress activation in the endometrial compartment likely triggered by implantation and its ability to increase the endometrial IFNβ levels.

Result(s)

In vitro, we observed a significant difference in the IFNβ levels in HESCs, in response to ER stress activation, where decidualized HESCs exhibited a threefold increase in the IFNβ levels compared with nondecidualized HESCs. Apoptotic caspase-3 activation was also isolated to the decidualized cells as a result of ER stress–dependent suppression of nuclear factor-kappa beta–regulated antiapoptotic factors, XIAP and MCL-1. In vivo, mouse endometrial IFNβ was present in F4/80-positive macrophages at all time points examined. After implantation (E6), the mouse luminal epithelial cells robustly coexpressed both IFNβ and the ER stress marker immunoglobulin heavy chain binding protein (BiP).

Conclusion(s)

These analyses demonstrate that both in vivo and in vitro, differentiated and decidualized endometrial cells undergoing ER stress have the capacity to produce increased IFNβ levels; therefore, ER stress activation in the endometrial compartment may play a vital role in promoting successful implantation events.

Objective

To examine the activation and consequence of uterine apoptotic caspase-3 action on 1 day after coitus (dpc) in the pregnant mouse. We have previously demonstrated that in a pregnant uterus, caspase-3 activation from mid to late gestation isolated to the myometrial compartment is largely nonapoptotic and controls uterine quiescence. Additionally, we had demonstrated that apoptotic caspase-3 activation isolated to the endometrial compartment at term regulated endometrial prostaglandin synthesis.

Design

Uteri were isolated from pseudopregnant and nonligated controls and unilateral and bilateral ligated uterine horn mouse models at 1, 3, and 6 dpc. Uteri were examined for apoptotic indices, such as caspase-3 activation and terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling staining. Immunohistochemical analysis identified the site of uterine apoptotic caspase-3 activation. The truncated form of phospholipase A2 was examined as a measure of apoptotic caspase-3–mediated calcium independent phospholipase A2 (iPLA2) activation.

Result(s)

We identified the site and impact of uterine apoptotic caspase-3 activation using uteri isolated from nonpregnant control animals at estrous and diestrous and control pregnant mice at 1–19 dpc. Our analysis revealed that apoptotic caspase-3 and iPLA2 activation were limited to the endometrial compartments of the control and unilateral ligated uteri on 1 dpc and were not found in the pseudopregnant or bilateral ligated uterine horn or on 3 or 6 dpc in the control and unilateral ligated uteri.

Conclusion(s)

In this study, we determined that uterine caspase-3 activation on 1 dpc, which is endometrial and apoptotic in nature, may play a potential role in regulating the previously reported preimplantation surge in endometrial PGE2 synthesis through apoptotic caspase-3–mediated iPLA2 activation. Our data indicate that the presence of a conceptus on 1 dpc likely triggers an increase in endometrial apoptotic caspase-3–mediated iPLA2 activation. When activated, iPLA2 causes the hydrolysis of fatty acids, resulting in arachidonic acid release and PGE2 production, which has been demonstrated to act in a leutoprotective manner in early pregnancy, prolonging progesterone synthesis and promoting uterine receptivity.

Objective

To assess the role of evaluating sperm chromatin fragmentation (SCF) as a tool to guide treatment in couples who achieved unexpectedly poor clinical outcomes after intracytoplasmic sperm injection (ICSI).

Design

We identified couples with an unexpectedly suboptimal clinical outcome after ICSI who were then screened for SCF. Consequently, the same couples were counseled to undergo a subsequent ICSI cycle using either ejaculates processed by microfluidic sperm selection (MFSS) or spermatozoa retrieved from the testis, and clinical outcomes were compared between history and treatment cycles. To confirm the sole effect of a compromised male gamete, we compared the ICSI outcome in cycles where male gametes with abnormal SCF were used to inseminate autologous and donor oocytes. Finally, to eliminate an eventual confounding female factor component, we compared the clinical outcome of ICSI cycles using sibling donor oocytes injected with spermatozoa with normal or abnormal SCF.

Setting

Academic reproductive medicine center point of care.

Patient(s)

The patient population consisted of 76 couples with reproductively healthy and relatively young female partners and male partners with compromised semen parameters, but suitable for ICSI. In a subanalysis, we identified 67 couples with abnormal SCF who underwent ICSI cycle(s) with donor oocytes. Furthermore, we identified 29 couples, 12 with normal SCF and 17 with abnormal, uncorrected SCF, and 7 couples with abnormal, corrected SCF vs. a control, who used sibling donor oocytes for their ICSI cycle(s).

Intervention(s)

For couples who resulted in surprisingly low clinical outcomes after ICSI, despite semen parameters adequate for ICSI and a normal female infertility evaluation, a SCF assessment was performed on the semen specimen using the terminal deoxynucleotidyl transferase-mediated fluorescein-deoxyuridine triphosphate nick-end labeling (TUNEL) assay. The couples then underwent a subsequent ICSI cycle with spermatozoa processed by MFSS or surgically retrieved. Moreover, cycles with donor oocytes were used to confirm the sole contribution of the male gamete.

Main Outcome Measure(s)

Clinical outcomes, such as fertilization, embryo implantation, clinical pregnancy, delivery, and pregnancy loss rates were compared between history and treatment cycle(s) using ejaculated spermatozoa selected by MFSS or from a testicular biopsy, taking into consideration the level of SCF. In a subanalysis, we reported the clinical outcomes of 67 patients who used donor oocytes and compared them with cycles where their own oocytes were used. Furthermore, we compared the ICSI clinical outcomes between cycles using sibling donor oocytes injected with low or high SCF with or without sperm intervention aimed at correcting, or alleviating the degree of SCF.

Result(s)