The steroid hormone estriol (E3) regulates epigenetic programming of fetal mouse brain and reproductive tract.

BACKGROUND: Estriol (E3) is a steroid hormone formed only during pregnancy in primates including humans. Although E3 is synthesized at large amounts through a complex pathway involving the fetus and placenta, it is not required for the maintenance of pregnancy and has classically been considered virtually inactive due to associated very weak canonical estrogen signaling. However, estrogen exposure during pregnancy may have an effect on organs both within and outside the reproductive system, and compounds with binding affinity for estrogen receptors weaker than E3 have been found to impact reproductive organs and the brain. Here, we explore potential effects of E3 on fetal development using mouse as a model system. RESULTS: We administered E3 to pregnant mice, exposing the fetus to E3. Adult females exposed to E3 in utero (E3-mice) had increased fertility and superior pregnancy outcomes. Female and male E3-mice showed decreased anxiety and increased exploratory behavior. The expression levels and DNA methylation patterns of multiple genes in the uteri and brains of E3-mice were distinct from controls. E3 promoted complexing of estrogen receptors with several DNA/histone modifiers and their binding to target genes. E3 functions by driving epigenetic change, mediated through epigenetic modifier interactions with estrogen receptors rather than through canonical nuclear transcriptional activation. CONCLUSIONS: We identify an unexpected functional role for E3 in fetal reproductive system and brain. We further identify a novel mechanism of estrogen action, through recruitment of epigenetic modifiers to estrogen receptors and their target genes, which is not correlated with the traditional view of estrogen potency.

Variations in incidence and mortality rates of endometrial cancer at the global, regional, and national levels, 1990-2019.

BACKGROUND: Endometrial cancer (EC) is a commonly diagnosed cancer in women. A comprehensive knowledge of its epidemiological features is essential for understanding the disease burden and guiding prevention strategies. METHODS: We retrieved the incidence and mortality data of EC from the Global Burden of Disease database. Estimated average percentage change (EAPC) was used to quantify the trends of the age-standardized incidence and mortality rates (ASIR and ASMR, respectively) of EC from 1990 to 2019. RESULTS: Globally, the ASIR of EC significantly increased by 0.69% (95% confidence interval [CI] 0.57-0.81%) per year between 1990 and 2019. This increasing trend was also observed in 160 countries or territories, regardless of the sociodemographic status. The most pronounced increase was found in Italy (EAPC = 4.81, 95% CI, 4.10-5.53), followed by Saudi Arabia and Singapore. Between 1990 and 2019, the ASMR of EC decreased significantly worldwide (EAPC = -0.85, 95% CI, -0.93 to -0.76) but increased significantly in 91 countries or territories, with the highest increase in Lesotho (EAPC = 3.27, 95% CI, 2.81-3.74). The ASMR-ASIR ratio of EC was higher in developing countries than in developed countries. This ratio showed a decreasing trend at the national level over the past three decades. CONCLUSIONS: EC incidence has ubiquitously increased worldwide. EC mortality has decreased at the global level but increased in many countries. More efforts are required to alleviate the disease burden of EC.

Repeated Superovulation Accelerates Primordial Follicle Activation and Atresia.

For humans, ARTs (assisted reproductive technologies) have become the most effective method to treat subfertility/infertility in clinic. To obtain enough oocytes during ART, ovarian stimulation is performed by exogenous hormones, and some patients undergo several ovarian stimulation cycles. Although some adverse effects of ARTs on women and offspring are reported, few studies are focused on the effects of multiple superovulation on ovarian reserve. In the present study, we found that repeated superovulation significantly reduced primordial follicle number and the serum AMH. Compared to the decreased antral follicle number, the expression of genes related to primordial follicle activation, such as Foxo3, Akt, and Rptor, and the atretic follicle number in ovaries were increased by superovulation times. We further found that repeated superovulation reduced the plasma level of FSH, LH, and estradiol, and increased the expression of genes related to apoptosis (Bax, Casp3 (caspase-3), Casp8, and Casp9) in granulosa cells, providing evidence that repeated superovulation disrupted the balance between survival and death in granulosa cells. In summary, our results suggest that repeated superovulation has adverse effects on folliculogenesis.

[Outcomes of ICSI with sperm from different sources: a retrospective study of 431 cycles].

OBJECTIVE: To compare the outcomes of intracytoplasmic sperm injection (ICSI) with retrieved epididymal and testicular sperm for obstructive azoospermia and with ejaculated sperm for severe oligozoospermia and asthenospermia. METHODS: We retrospectively analyzed 431 ICSI cycles, which were divided according to sperm sources into Groups A (n=287 in patients with severe oligozoospermia or asthenospermia using ejaculated sperm), B (n=109 in obstructive azoospermia patients with sperm retrieved by percutaneous epididymal sperm aspiration, PESA) and C (n=35 in obstructive azoospermia patients with sperm retrieved by testicular sperm extraction, TESE). Comparisons were made among the three groups in the rates of embryo implantation, fertilization, pregnancy, cleavage, and miscarriage. RESULTS: Group A showed statistically significant differences from Groups B and C in the rates of embryo implantation and pregnancy (18.46% vs. 25.23% and 28.76%, 31.23% vs. 42.16% and 39.39%, P < 0.05). But no significant differences were seen in the rates of fertilization, cleavage and miscarriage among the three groups (P > 0.05). CONCLUSION: The rates of embryo implantation and clinical pregnancy are higher in patients with obstructive azoospermia than in those with severe oligozoospermia or asthenospermia after ICSI with ejaculated sperm.

Abnormal expression of TLRs may play a role in lower embryo quality of women with polycystic ovary syndrome.

Toll-like receptors (TLRs) localize in mammalian ovary, including granulosa cells, cumulus cells, and theca cells. Previous studies demonstrated that TLRs may be important for the cumulus-oocyte complex expansion and fertilization. There is no evidence to indicate that the deletion of TLRs will induce infertility; however, the abnormal expression of TLRs may decrease oocyte quality and fertility rate. In the present study, we investigated the effects of polycystic ovary syndrome (PCOS) on the expression of TLRs in cumulus cells by using western-blot and quantitative real-time PCR (qRT-PCR) analyses. We found that the expression of TLR4 and 9 in cumulus cells was influenced significantly by PCOS. We also observed that overweight/obesity changed the expression of TLR2 and 5 in cumulus cells of PCOS subjects. In addition, we found that the rate of available embryos of women with PCOS was slightly lower. These results indicate that the abnormal expression of TLRs in cumulus may be a reason for the lower embryo quality of women with PCOS. ABBREVIATIONS: ART: assisted reproductive technology BMI: body mass index COC: cumulus-cell-oocyte complex PCOS: polycystic ovary syndrome q RT-PCR: quantitative real-time PCR TLRs: Toll-like receptors.