Vertical transmission of microbiomes into embryo culture media and its association with assisted reproductive outcomes.

RESEARCH QUESTION: Can microbes vertically transmit from semen and follicular fluid to embryo culture media during assisted reproductive technology (ART) treatment? DESIGN: Spent embryo culture media (SECM), seminal fluid and follicular fluid samples were collected from 61 couples with infertility undergoing ART treatment at the Prince of Wales Hospital, Hong Kong SAR, China. Metagenomic analysis was conducted using 16s rRNA sequencing to identify the source of microbes in SECM, correlation between the semen microbiome and male infertility, and correlation between the follicular fluid microbiome and female infertility. RESULTS: Microbial vertical transmission into SECM was reported in 82.5% of cases, and semen was the main source of contamination in conventional IVF cases. The increased abundances of Staphylococcus spp. and Streptococcus anginosus in semen had negative impacts on total motility and sperm count, respectively (P < 0.001). Significant increases in abundance of the genera Prophyromonas, Neisseria and Facklamia were observed in follicular fluid in women with anovulation, uterine factor infertility and unexplained infertility, respectively (P < 0.01). No significant correlation was found between the bacteria identified in all sample types and ART outcomes, including fertilization rate, embryo development, number of available embryos, and clinical pregnancy rate. CONCLUSION: Embryo culture media can be contaminated during ART treatment, not only by seminal microbes but also by follicular fluid and other sources of microbes. Strong correlations were found between specific microbial taxa in semen and sperm quality, and between the follicular fluid microbiome and the aetiology of female infertility. However, no significant association was found between the microbiomes of SECM, semen and follicular fluid and ART outcomes.

NADase CD38 is a key determinant of ovarian aging.

The ovary ages earlier than most other tissues, yet the underlying mechanisms remain elusive. Here a comprehensive analysis of transcriptomic landscapes in different organs in young and middle-aged mice revealed that the ovaries showed earlier expression of age-associated genes, identifying increased NADase CD38 expression and decreased NAD+ levels in the ovary of middle-aged mice. Bulk and single-cell RNA sequencing revealed that CD38 deletion mitigated ovarian aging, preserving fertility and follicle reserve in aged mice by countering age-related gene expression changes and intercellular communication alterations. Mechanistically, the earlier onset of inflammation induced higher expression levels of CD38 and decreased NAD+ levels in the ovary, thereby accelerating ovarian aging. Consistently, pharmacological inhibition of CD38 enhanced fertility in middle-aged mice. Our findings revealed the mechanisms underlying the earlier aging of the ovary relative to other organs, providing a potential therapeutic target for ameliorating age-related female infertility.

Mature Cystic Teratoma: An Integrated Review.

Ovarian dermoid cysts, also called mature cystic teratomas (MCTs), account for 69% of ovarian germ cell tumors in young women. The tumors are formed by tissues derived from three germ layers, and sebaceous materials are most commonly seen. The origin of MCTs is widely considered to be the germ cell origin, which completes meiosis I. The clinical symptoms vary widely, but 20% of tumors could be asymptomatic. The diagnosis of MCTs is usually made without difficulty by ultrasound and confirmed by histopathology post-operatively. The imaging findings have a high diagnostic value. The typical characteristics present in the sonographic images, including a dermoid plug or Rokitansky nodule, are considered strong evidence for a teratoma. Although the malignant transformation of MCTs is rare, it can occur in some cases, especially in women of advanced age. The treatment of MCTs depends on the risk of malignancy, the age of the patient, and the patient's fertility reserve requirement. In this article, we review the epidemiology, clinical symptoms, diagnosis criteria, cellular origin, and treatment of mature cystic teratomas.

Sirt3 deficiency accelerates ovarian senescence without affecting spermatogenesis in aging mice.

Sirtuin-3 (SIRT3), the main deacetylase in the mitochondria, maintains cellular energy metabolism and redox balance by deacetylating mitochondrial proteins in a NAD+-dependent manner. Growing evidence indicates that decreased Sirt3 expression is involved in various age-related maladies. However, the role of Sirt3 in ovarian and testicular senescence remains unclear. In this study, we observed that sirt3 expression showed age-dependent decreases in the ovary but not the testis. We generated Sirt3 null mice via CRISPR/Cas9-mediated genome editing. We observed that Sirt3 deletion accelerated ovarian aging, as shown by a decrease in offspring sizes, the follicle reserve and oocytes markers (Bmp15 and Gdf9) as well as increased expression of aging and inflammation-related genes (p16, p21, Il-1α, and Il-1ß). Sirt3 deficiency led to an accumulation of superoxide and disruption of spindle assembly accompanied by mitochondrial dysfunction (uneven mitochondria distribution, decreased mitochondrial potential as well as reduced mitochondrial DNA content) in aging oocytes. Meanwhile, in ovaries of Sirt3 null mice, the impaired mitochondrial functions were shown by decreases in mitochondrial respiratory complexes, along with lower levels of mitochondrial fusion (OPA1, MFN2) and fission (DRP1, FIS1) proteins. er levels of mitochondrial fusion (OPA1, MFN2) and fission (DRP1, FIS1) proteins. Interestingly, Sirt3-/- male mice exhibited no changes on the testicular histology, serum testosterone levels, germ-cell proliferation, and differentiation of spermatogonia. Meiotic prophase I spermatocytes were also normal. Levels of superoxide, mitochondrial potential as well as expression of mitochondrially-encoded genes were unaltered in Sirt3-/- testes. Collectively, the results indicated that SIRT3 plays a critical role in maintaining the ovarian follicle reserve and oocyte quality in aging mice, suggesting its important role in controlling ovarian senescence.

Myostatin: a multifunctional role in human female reproduction and fertility - a short review.

Myostatin (MSTN) is member of the transforming growth factor ß (TGF-ß) superfamily and was originally identified in the musculoskeletal system as a negative regulator of skeletal muscle growth. The functional roles of MSTN outside of the musculoskeletal system have aroused researchers' interest in recent years, with an increasing number of studies being conducted in this area. Notably, the expression of MSTN and its potential activities in various reproductive organs, including the ovary, placenta, and uterus, have recently been examined. Numerous studies published in the last few years demonstrate that MSTN plays a critical role in human reproduction and fertility, including the regulation of follicular development, ovarian steroidogenesis, granule-cell proliferation, and oocyte maturation regulation. Furthermore, findings from clinical samples suggest that MSTN may play a key role in the pathogenesis of several reproductive disorders such as uterine myoma, preeclampsia (PE), ovary hyperstimulation syndrome (OHSS), and polycystic ovarian syndrome (PCOS). There is no comprehensive review regarding to MSTN related to the female reproductive system in the literature. This review serves as a summary of the genes in reproductive medicine and their potential influence. We summarized MSTN expression in different compartments of the female reproductive system. Subsequently, we discuss the role of MSTN in both physiological and several pathological conditions related to the female fertility and reproduction-related diseases.

NAD+ deficiency and mitochondrial dysfunction in granulosa cells of women with polycystic ovary syndrome‡.

Polycystic ovary syndrome (PCOS) is a prevalent heterogeneous endocrine disorder characterized by ovulation dysfunction, androgen excess, ovarian polycystic changes, insulin resistance, and infertility. Although underlying mechanisms for PCOS are still unknown, inflammation and mitochondrial dysfunction in granulosa cells (GCs) of PCOS patients have been reported. Here, we found that Nicotinamide Adenine Dinucleotide (NAD+) levels in GCs of PCOS patients was significantly decreased when compared with controls. Also, we found that higher expression of inflammation factors, increased reactive oxygen species (ROS) accumulation, lower adenosine triphosphate (ATP) generation, and decreased mitochondrial membrane potential, as well as abnormal mitochondrial dynamics in GCs of PCOS patients. In addition, the NAD+ levels were decreased after activation of inflammation in human granulosa-like tumor cell line (KGN) treated by Lipopolysaccharide (LPS). However, supplementation of nicotinamide riboside (NR), a NAD+ precursor, could largely restore the NAD+ content, reduce ROS levels and improve mitochondrial function demonstrated by increased mitochondrial membrane potential and ATP generation in LPS-treated KGN cells. Our data suggested that inflammation decreased NAD+ levels in GCs of PCOS patients, while supplementation of NR could restore NAD+ levels and alleviated mitochondrial dysfunction in GCs of PCOS patients.

Increasing ovarian NAD+ levels improve mitochondrial functions and reverse ovarian aging.

Loss of follicles together with decreased oocyte quality and quantity contribute to age-associated ovarian senescence and infertility. Although underlying mechanisms for ovarian senescence are still unknown, mitochondrial dysfunctions have been reported. Here, we showed age-dependent decreases in ovarian Nicotinamide Adenine Dinucleotide (NAD+) levels in mice whereas supplementing aging mice with nicotinamide riboside (NR), an NAD+ precursor, increased ovarian NAD+ content. We found that increases in ovarian NAD+ levels in aging mice led to increased number of ovarian follicles and ovulatory potential as well as increased live birth rate. NR supplementation also reduced levels of reactive oxygen species and decreased spindle anomalies in aging oocytes, together with increased mitochondrial membrane potential (ΔΨm) and decreased mitochondrial clustering. In addition, NR supplementation improved ovarian mitochondrial energy metabolism. Our data suggested that supplementation with NAD+ precursors in vivo and in vitro could be potential therapeutic approaches for treating age-related ovarian infertility.

Melatonin attenuates cadmium-induced ovulatory dysfunction by suppressing endoplasmic reticulum stress and cell apoptosis.

BACKGROUND: Increasing evidence demonstrate that cadmium (Cd) has adverse effects on the mammalian reproductive system. However, the mechanisms underlying the effects of Cd on ovarian function and the strategies to reverse these effects have not been fully elucidated. METHODS: In this study, 60 CD-1 mice were divided into four groups (control, melatonin, Cd, Cd with melatonin). During the treatment for 14 days, body weight was measured every 2 days. After the treatment, ovaries were isolated and weighted to observe the morphological and biological characteristics. Statistical analyses were performed using one-way ANOVA followed by Fisher's-multiple range test or chi-squared test, A P value < 0.05 indicated statistical significance. RESULTS: We observed that Cd exposure induced ovulatory dysfunction, demonstrated by the reduced number of ovulated oocytes numbers in the Cd group. However, this endoplasmic reticulum (ER) pathway was activated in the Cd-exposed ovaries and the expression of GRP78, ATF4, CHOP, and p-JNK was upregulated, which was reversed by treatment with melatonin. Furthermore, we found that melatonin inhibited Cd-induced activation of cleaved caspase-3, restored the ratio of Bax/Bcl-2, and ultimately decreased the apoptosis of granular cells as detected by TUNEL staining. CONCLUSION: Collectively, our findings reveal that melatonin attenuated Cd-induced ovulation dysfunction and cell apoptosis by inhibiting the activation of the ER pathway. Thus, melatonin can be a potential agent to protect mammalian ovaries against Cd toxicity.