Inhibition of Oocyte Maturation by Follicular Extracellular Vesicles of Nonhyperandrogenic PCOS Patients Requiring IVF.

CONTEXT: Polycystic ovary syndrome (PCOS) is one of the most common diseases that contribute to subfertility. Recent evidence showed that oocytes of women with PCOS matured in vitro away from the follicular fluid presented better potentials, whereas the reason remained unclear. OBJECTIVE: This work aimed to investigate whether follicular extracellular vesicles (EVs) of PCOS patients interfere with the quality of oocytes. METHODS: Follicular EVs of women with PCOS (PCOS-EVs) and control women (CTRL-EVs) were isolated and determined using Western blotting, nanoparticle tracking analysis, and transmission electron microscopy. The 2 types of EVs were co-cultured with murine germinal vesicle oocytes, respectively. Fluorescence-labeled EVs were used to visualize internalization by oocytes. After co-culture, oocyte maturation rates were calculated. Mitochondria distribution and reactive oxygen species (ROS) level were detected in the different groups. Spindle morphology was evaluated using immunofluorescence. Moreover, the expression of catalase (CAT), glutathione synthetase (GSS), and superoxide dismutase (SOD) was determined in the oocytes. RESULTS: Both PCOS-EVs and CTRL-EVs are bilayered vesicles, approximately 100 to 150 nm in size, and enriched in EV-associating protein markers. EVs were internalized by oocytes within 1 hour. Oocyte maturation rate decreased significantly in the PCOS-EV group compared with the CTRL-EV group, whereas the abnormal mitochondria distribution rate and abnormal spindle rate were significantly increased in the PCOS-EV group. Moreover, PCOS-EVs increased the ROS level and the expression of CAT, GSS, and SOD in the oocytes. CONCLUSION: PCOS-EVs interfered with oocyte mitochondria and spindles and inhibited oocyte maturation. Moreover, oxidative stress induced by PCOS-EVs might be a potential cause.

The Impact of Embryo Storage Time on Pregnancy and Perinatal Outcomes and the Time Limit of Vitrification: A Retrospective Cohort Study.

Background: The technique of embryo cryopreservation has been increasingly applied in clinical settings. However, there has been a concern about the safety and efficacy of long-term freezing of embryos. Therefore, the aim of this study was to evaluate whether storage time of vitrification had any effects on pregnancy as well as perinatal outcomes, further, to explore the appropriate time limit of vitrification. Methods: The study included women who underwent at least one frozen-thawed cycle with single embryo transfer between January 1st, 2016 and September 30th, 2019. Patients were assigned into 3 groups according to the storage time (<3 months, 3-12 months and >12 months) to evaluate the impact of embryo storage time on pregnancy and perinatal outcomes. To further investigate the time limit of vitrification, propensity score matching was used to compare the primary outcomes of patients with storage time of 1-3 years, 3-5 years, and >5 years to those stored for ≤1 year. Results: A total of 9806 frozen-thawed embryo transfer cycles were included in our study. After adjustment for confounding variables, no significant differences were found in pregnancy outcomes among groups. However, postponement of transfer increased the risks of large for gestational age and placenta previa. In addition, after propensity score matching, 171 cycles with storage time >5 years were matched with those ≤1 year, both the clinical pregnancy rate and live birth rate decreased significantly when the storage time exceeded 5 years. Conclusions: The duration of vitrification did not significantly affect the pregnancy outcomes within 5 years period. However, the clinical pregnancy rate and live birth rate both decreased significantly when the duration of vitrification exceeded 5 years. It is worth noting that the conclusion was drawn from a small sample study after propensity score matching and should be treated with caution. In addition, the cycles were from different time periods, which could have an impact on the results.

Reprogramming astrocytes to motor neurons by activation of endogenous Ngn2 and Isl1.

Central nervous system injury and neurodegenerative diseases cause irreversible loss of neurons. Overexpression of exogenous specific transcription factors can reprogram somatic cells into functional neurons for regeneration and functional reconstruction. However, these practices are potentially problematic due to the integration of vectors into the host genome. Here, we showed that the activation of endogenous genes Ngn2 and Isl1 by CRISPRa enabled reprogramming of mouse spinal astrocytes and embryonic fibroblasts to motor neurons. These induced neurons showed motor neuronal morphology and exhibited electrophysiological activities. Furthermore, astrocytes in the spinal cord of the adult mouse can be converted into motor neurons by this approach with high efficiency. These results demonstrate that the activation of endogenous genes is sufficient to induce astrocytes into functional motor neurons in vitro and in vivo. This direct neuronal reprogramming approach may provide a novel potential therapeutic strategy for treating neurodegenerative diseases and spinal cord injury.

Differential immune responses in pregnant patients recovered from COVID-19.

Pregnant women are generally more susceptible to viral infection. Although the impact of SARS-CoV-2 in pregnancy remains to be determined, evidence indicates that the risk factors for severe COVID-19 are similar in pregnancy to the general population. Here we systemically analyzed the clinical characteristics of pregnant and non-pregnant female COVID-19 patients who were hospitalized during the same period and found that pregnant patients developed marked lymphopenia and higher inflammation evident by higher C-reactive protein and IL-6. To elucidate the pathways that might contribute to immunopathology or protective immunity against COVID-19 during pregnancy, we applied single-cell mRNA sequencing to profile peripheral blood mononuclear cells from four pregnant and six non-pregnant female patients after recovery along with four pregnant and three non-pregnant healthy donors. We found normal clonal expansion of T cells in the pregnant patients, heightened activation and chemotaxis in NK, NKT, and MAIT cells, and differential interferon responses in the monocyte compartment. Our data present a unique feature in both innate and adaptive immune responses in pregnant patients recovered from COVID-19.

Transient impact of paclitaxel on mouse fertility and protective effect of gonadotropin­releasing hormone agonist.

Paclitaxel (PXL) is a chemotherapeutic agent widely used in solid tumors. However, whether PXL causes premature ovarian insufficiency in women of reproductive age remains controversial. The aim of the present study was to answer how and for how long PXL affects fertility, and to identify the protective effect of gonadotropin­releasing hormone agonist (GnRHa) in mice. A single dose of PXL was administered to 7­week­old female ICR mice. Mice were treated with GnRHa for 1 estrous cycle prior to chemotherapy, and for another following chemotherapy. On the days 1, 6, 11 and 16 following the administration of PXL, mice were assessed by ovarian histology, ovarian stimulation and mating experiment. Multiple doses of PXL were also administered to verify the duration of the gonadotoxicity of PXL. It was determined that PXL only destroyed antral follicles on day 1 following chemotherapy without reducing primordial follicles. In vitro experiments revealed that PXL impaired oocytes in metaphase, excluding those at the germinal vesicle stage. The number and quality of retrieved metaphaseⅡ(MⅡ) oocytes in PXL­exposed mice were reduced on day 1 following chemotherapy, which was recovered on day 11. MⅡ oocytes from mice pretreated with GnRHa recovered on day 6 following chemotherapy. Following 3 estrous cycles in mice after the last dose of the 3­dose paclitaxel administration, follicles in all stages and retrieved MII oocytes were recovered. It was concluded that the impairment caused by PXL on follicles and oocytes in mice lasted for <3 estrous cycles, which was shortened by pretreatment of GnRHa.