The effect of DHEA on apoptosis and cohesin levels in oocytes in aged mice

[Predictive factors of spontaneous pregnancies among women with diminished ovarian reserve patients treated with DHEA]

INTRODUCTION

Diminished ovarian reserve remains a challenge in the reproductive medicine field. Treatment options for these patients are limited and there is no consensus to make any recommendations. Regarding adjuvant supplements, DHEA could play a role in follicular recruitment and, therefore, may increase spontaneous pregnancy rate.

MATERIALS AND METHODS

This study was a monocentric historical and observational cohort study carried out in the reproductive medicine department at the University Hospital, Femme-Mère-Enfant in Lyon. All women presenting with a diminished ovarian reserve treated with 75mg/day of DHEA were consecutively included. The main objective was to evaluate the spontaneous pregnancy rate. The secondary objectives were to identify predictive factors for pregnancy and the evaluation of treatment side effects.

RESULTS

Four hundred and thirty-nine women were included. In all, 277 were analyzed, 59 had a spontaneous pregnancy (21.3%). The probability of being pregnant was respectively 13.2% (IC95 9-17.2%), 21.3% (IC95 15.1-27%) and 38.8% (IC95 29.3-48.4%) at 6, 12 and 24 months. Only 20.6% of patients complained of side effects.

CONCLUSION

DHEA may improve spontaneous pregnancies in women with diminished ovarian reserve without any stimulation.

Metabolic Mechanisms and Potential Therapeutic Targets for Prevention of Ovarian Aging: Data from Up-to-Date Experimental Studies

Female infertility and reproduction is an ongoing and rising healthcare issue, resulting in delaying the decision to start a family. Therefore, in this review, we examine potential novel metabolic mechanisms involved in ovarian aging according to recent data and how these mechanisms may be addressed through new potential medical treatments. We examine novel medical treatments currently available based mostly on experimental stem cell procedures as well as caloric restriction (CR), hyperbaric oxygen treatment and mitochondrial transfer. Understanding the connection between metabolic and reproductive pathways has the potential to offer a significant scientific breakthrough in preventing ovarian aging and prolonging female fertility. Overall, the field of ovarian aging is an emerging field that may expand the female fertility window and perhaps even reduce the need for artificial reproductive techniques.

Investigation of Physiological Effects Induced by Dehydroepiandrosterone in Human Endothelial Cells and Ovarian Cancer Cell Line

Objectives

Dehydroepiandrosterone (DHEA) is an endogenous hormone that acts as a ligand for several cellular receptors. An age-dependent decline in circulating levels of DHEA is linked to changes in various physiological functions. In gynecological clinical practice, DHEA is commonly prescribed to induce ovulation. Some clinical studies report a positive association between high serum concentrations of DHEA and an increased risk of developing ovarian cancer. However, the in vitro physiological effects of DHEA on ovarian cancerous cells have not been explored thus far. In this study, we aimed to investigate the physiological effects of DHEA treatment (0-200 μM, 24-72 hours) on MDAH-2774 human ovarian cancer cell line and primary HuVeC human endothelial cells.

Materials and Methods

The physiological effects of DHEA treatment (0-200 μM, 24-72 hours) on MDAH-2774 human ovarian cancer cell line and primary HuVeC human endothelial cells were investigated with the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test, acridine orange/ethidium bromide staining, and scratch assay.

Results

DHEA treatment promoted proliferation of the MDAH-2774 cancer cell line in a dose-dependent manner (r=0.6906, p<0.0001, for 24 hours) (r=0.6802, p<0.0001, for 48 hours) (r=0.7969, p<0.0001, for 72 hours). In contrast, DHEA inhibited proliferation of the primary HuVeC cells (r=0.9490, p<0.0001, for 24 hours) (r=0.9533, p<0.0001, for 48 hours) (r=0.9584, p<0.0001, for 72 hours). In agreement with these observations, DHEA treatment resulted in a dose-dependent increase in the number of necrotic cells in the primary HuVeC cells (r=0.97, p<0.0001). However, the number of necrotic or apoptotic cells did not change significantly when the MDAH-2774 cells was exposed to DHEA. Moreover, we found that DHEA treatment reduced the migration rate of HuVeC cells in a dose-dependent manner (r=0.9868, p<0.0001), whereas only a slight increase was observed in the MDAH-2774 ovarian cancer cell line (r=0.8938, p<0.05).

Conclusion

Our findings suggest that DHEA promotes the proliferation of ovarian cancer cells in a dose-dependent manner in vitro. Moreover, DHEA induced necrosis and inhibited proliferation in endothelial cells. Although mechanistic evidence is required, our preliminary findings imply that exposure to high doses of DHEA may be associated with an increased risk of developing ovarian cancer.

IGF2 improves the developmental competency and meiotic structure of oocytes from aged mice

Advanced maternal-age is a major factor adversely affecting oocyte quality, consequently worsening pregnancy outcomes. Thus, developing strategies to reduce the developmental defects associated with advanced maternal-age would benefit older mothers. Multiple growth factors involved in female fertility have been extensively studied; however, the age-related impacts of various growth factors remain poorly studied. In the present study, we identified that levels of insulin-like growth factor 2 (IGF2) are significantly reduced in the serum and oocytes of aged mice. We found that adding IGF2 in culture medium promotes oocyte maturation and significantly increases the proportion of blastocysts: from 41% in the untreated control group to 64% (50 nM IGF2) in aged mice (p < 0.05). Additionally, IGF2 supplementation of the culture medium reduced reactive oxygen species production and the incidence of spindle/chromosome defects. IGF2 increases mitochondrial functional activity in oocytes from aged mice: we detected increased ATP levels, elevated fluorescence intensity of mitochondria, higher mitochondrial membrane potentials, and increased overall protein synthesis, as well as increased autophagy activity and decreased apoptosis. Collectively, our findings demonstrate that IGF2 supplementation in culture media improves oocyte developmental competence and reduces meiotic structure defects in oocytes from aged mice.

A Preliminary Study on the Characteristics of microRNAs in Ovarian Stroma and Follicles of Chuanzhong Black Goat during Estrus

microRNAs (miRNAs) play a significant role in ovarian follicular maturity, but miRNA expression patterns in ovarian stroma (OS), large follicles (LF), and small follicles (SF) have been rarely explored. We herein aimed to identify miRNAs, their target genes and signaling pathways, as well as their interaction networks in OS, LF, and SF of Chuanzhong black goats at the estrus phase using small RNA-sequencing. We found that the miRNA expression profiles of LF and SF were more similar than those of OS—32, 16, and 29 differentially expressed miRNAs were identified in OS vs. LF, OS vs. SF, and LF vs. SF, respectively. Analyses of functional enrichment and the miRNA-targeted gene interaction network suggested that miR-182 (SMC3), miR-122 (SGO1), and miR-206 (AURKA) were involved in ovarian organogenesis and hormone secretion by oocyte meiosis. Furthermore, miR-202-5p (EREG) and miR-485-3p (FLT3) were involved in follicular maturation through the MAPK signaling pathway, and miR-2404 (BMP7 and CDKN1C) played a key role in follicular development through the TGF-β signaling pathway and cell cycle; nevertheless, further research is warranted. To our knowledge, this is the first study to investigate miRNA expression patterns in OS, LF, and SF of Chuanzhong black goats during estrus. Our findings provide a theoretical basis to elucidate the role of miRNAs in follicular maturation. These key miRNAs might provide candidate biomarkers for the diagnosis of follicular maturation and will assist in developing new therapeutic targets for female goat infertility.

Chemically induced aneuploidy in germ cells. Part II of the report of the 2017 IWGT workgroup on assessing the risk of aneugens for carcinogenesis and hereditary diseases

As part of the 7th International Workshops on Genotoxicity Testing held in Tokyo, Japan in November 2017, a workgroup of experts reviewed and assessed the risk of aneugens for human health. The present manuscript is one of three manuscripts from the workgroup and reports on the unanimous consensus reached on the evidence for aneugens affecting germ cells, their mechanisms of action and role in hereditary diseases. There are 24 chemicals with strong or sufficient evidence for germ cell aneugenicity providing robust support for the ability of chemicals to induce germ cell aneuploidy. Interference with microtubule dynamics or inhibition of topoisomerase II function are clear characteristics of germ cell aneugens. Although there are mechanisms of chromosome segregation that are unique to germ cells, there is currently no evidence for germ cell-specific aneugens. However, the available data are heavily skewed toward chemicals that are aneugenic in somatic cells. Development of high-throughput screening assays in suitable animal models for exploring additional targets for aneuploidy induction, such as meiosis-specific proteins, and to prioritize chemicals for the potential to be germ cell aneugens is encouraged. Evidence in animal models support that: oocytes are more sensitive than spermatocytes and somatic cells to aneugens; exposure to aneugens leads to aneuploid conceptuses; and, the frequencies of aneuploidy are similar in germ cells and zygotes. Although aneuploidy in germ cells is a significant cause of infertility and pregnancy loss in humans, there is currently limited evidence that aneugens induce hereditary diseases in human populations because the great majority of aneuploid conceptuses die in utero. Overall, the present work underscores the importance of protecting the human population from exposure to chemicals that can induce aneuploidy in germ cells that, in contrast to carcinogenicity, is directly linked to an adverse outcome.