Senataxin: A New Guardian of the Female Germline Important for Delaying Ovarian Aging

Study on the clinical value of Vitamin D in recurrent spontaneous abortion: Revisiting the Importance of Vitamin D

OBJECTIVE

This study explores the possible pathogenesis of recurrent spontaneous abortion (RSA) caused by vitamin D (VD), provides evidence-based bases for prevention and treatment of RSA, improves female reproductive health.

METHODS

This study randomly selected 305 patients without spontaneous abortion (SA0), 216 patients with a spontaneous abortion (SA1) and 200 patients with RSA from 1421 women of childbearing age who visited the RSA specialty clinic of Hangzhou First People's Hospital from January 2021 to June 2023 to conduct a prospective clinical study. Then, we collected the data of clinical diagnosis and treatment, conducted intervention and follow-up, and finally executed statistical analysis.

RESULTS

(1) RSA patients were significantly older than the other two groups. (2) The rates of VD deficiency in SA1 and RSA patients were significantly higher than those in SA0. (3) When BMI < 20  or > 24 kg/m2 , there were abnormal increase in VD and increased number of spontaneous abortions. (4) The bilateral S/D of the VD-sufficient, VD-insufficient and VD-deficient groups gradually increased with statistical significance (p ≤ .018). (5) Among the 65 cases undergoing embryo chromosome examinations, chromosomal abnormalities accounted for 55.38% and 69.05% in RSA patients. (6) Among 186 patients with abnormal ACA, there was a certain negative correlation between ACA and VD, which was stronger among RSA patients. Moreover, ACA significantly decreased (p < .001) after effectively supplementing VD, and the miscarriage rate of re-pregnancy also decreased.

CONCLUSION

The rate of VD deficiency is higher in RSA patients. VD deficiency may be related to the age of women of childbearing age and too low or high BMI, and may cause abnormal plasma antiphospholipid antibodies, increased uterine artery resistance and abnormal chromosomal division during fertilization, leading to spontaneous abortion and even RSA. The improvement of VD deficiency may reduce the risk of RSA occurrence.

Facilitation of Ovarian Response by Mechanical Force-Latest Insight on Fertility Improvement in Women with Poor Ovarian Response or Primary Ovarian Insufficiency

The decline in fertility in aging women, especially those with poor ovarian response (POR) or primary ovarian insufficiency (POI), is a major concern for modern IVF centers. Fertility treatments have traditionally relied on gonadotropin- and steroid-hormone-based IVF practices, but these methods have limitations, especially for women with aging ovaries. Researchers have been motivated to explore alternative approaches. Ovarian aging is a complicated process, and the deterioration of oocytes, follicular cells, the extracellular matrix (ECM), and the stromal compartment can all contribute to declining fertility. Adjunct interventions that involve the use of hormones, steroids, and cofactors and gamete engineering are two major research areas aimed to improve fertility in aging women. Additionally, mechanical procedures including the In Vitro Activation (IVA) procedure, which combines pharmacological activators and fragmentation of ovarian strips, and the Whole Ovary Laparoscopic Incision (WOLI) procedure that solely relies on mechanical manipulation in vivo have shown promising results in improving follicle growth and fertility in women with POR and POI. Advances in the use of mechanical procedures have brought exciting opportunities to improve fertility outcomes in aging women with POR or POI. While the lack of a comprehensive understanding of the molecular mechanisms that lead to fertility decline in aging women remains a major challenge for further improvement of mechanical-manipulation-based approaches, recent progress has provided a better view of how these procedures promote folliculogenesis in the fibrotic and avascular aging ovaries. In this review, we first provide a brief overview of the potential mechanisms that contribute to ovarian aging in POI and POR patients, followed by a discussion of measures that aim to improve ovarian folliculogenesis in aging women. At last, we discuss the likely mechanisms that contribute to the outcomes of IVA and WOLI procedures and potential future directions.

Non-linear Relationship of Maternal Age With Risk of Spontaneous Abortion: A Case-Control Study in the China Birth Cohort

Background

Spontaneous abortion is one of the prevalent adverse reproductive outcomes, which seriously threatens maternal health around the world.

Objective

The current study is aimed to evaluate the association between maternal age and risk for spontaneous abortion among pregnant women in China.

Methods

This was a case-control study based on the China Birth Cohort, we compared 338 cases ending in spontaneous abortion with 1,352 controls resulting in normal live births. The main exposure indicator and outcome indicator were maternal age and spontaneous abortion, respectively. We used both a generalized additive model and a two-piece-wise linear model to determine the association. We further performed stratified analyses to test the robustness of the association between maternal age and spontaneous abortion in different subgroups.

Results

We observed a J-shaped relationship between maternal age and spontaneous abortion risk, after adjusting for multiple covariates. Further, we found that the optimal threshold age was 29.68 years old. The adjusted odds ratio (95% confidence interval) of spontaneous abortion per 1 year increase in maternal age were 0.97 (0.90–1.06) on the left side of the turning point and 1.25 (1.28–1.31) on the right side. Additionally, none of the covariates studied modified the association between maternal age and spontaneous abortion (P > 0.05).

Conclusions

Advanced maternal age (>30 years old) was significantly associated with increased prevalence of spontaneous abortion, supporting a J-shaped association between maternal age and spontaneous abortion.

Adipose tissue and ovarian aging: Potential mechanism and protective strategies

Ovarian aging occurs approximately 10 years prior to the natural age-associated functional decline of other organ systems. With the increase of life expectancy worldwide, ovarian aging has gradually become a key health problem among women. Therefore, understanding the causes and molecular mechanisms of ovarian aging is very essential for the inhibition of age-related diseases and the promotion of health and longevity in women. Recently, studies have revealed an association between adipose tissue (AT) and ovarian aging. Alterations in the function and quantity of AT have profound consequences on ovarian function because AT is central for follicular development, lipid metabolism, and hormonal regulation. Moreover, the interplay between AT and the ovary is bidirectional, with ovary-derived signals directly affecting AT biology. In this review, we summarize the current knowledge of the complex molecular mechanisms controlling the crosstalk between the AT and ovarian aging, and further discuss how therapeutic targeting of the AT can delay ovarian aging.

Local DNA synthesis is critical for DNA repair during oocyte maturation

Mammalian oocytes can be very long-lived cells and thereby are very likely to encounter DNA damage during their lifetime. Defective DNA repair may result in oocytes that are developmentally incompetent or give rise to progeny with congenital disorders. During oocyte maturation, damaged DNA is repaired primarily by non-homologous end joining (NHEJ) or homologous recombination (HR). Although these repair pathways have been studied extensively, the associated DNA synthesis is poorly characterized. Here, using porcine oocytes, we demonstrate that the DNA synthesis machinery is present during oocyte maturation and dynamically recruited to sites of DNA damage. DNA polymerase δ is identified as being crucial for oocyte DNA synthesis. Furthermore, inhibiting synthesis causes DNA damage to accumulate and delays the progression of oocyte maturation. Importantly, inhibition of the spindle assembly checkpoint (SAC) bypassed the delay of oocyte maturation caused by DNA synthesis inhibition. Finally, we found that ∼20% of unperturbed oocytes experienced spontaneously arising damage during maturation. Cumulatively, our findings indicate that oocyte maturation requires damage-associated DNA synthesis that is monitored by the SAC. This article has an associated First Person interview with the first author of the paper.