[Endometriosis and miscarriage: Systematic review]

Causal Relationship Between Abortion and Endometriosis: A Bidirectional Two-Sample Mendelian Randomization Study

PROBLEM

The relationship between abortion and endometriosis (EMS) has been inconsistent in previous observational studies and remains controversial. We intended to examine the causal relationship between abortion and EMS.

METHODS OF STUDY

We conducted a Mendelian randomization (MR) analysis using genome-wide association study (GWAS) summary statistics, drawing data from the FinnGen database and the UK Biobank. The primary analysis utilized the random-effects inverse variance weighted (IVW) approach, complemented by weighted median, weighted mode, and MR-Egger methods. Comprehensive sensitivity analyses were conducted, encompassing the Cochran's Q statistic for assessing heterogeneity and MR-PRESSO to detect pleiotropy. Additionally, Leave-One-Out (LOO) analysis was conducted to confirm the stability of our results.

RESULTS

The IVW method revealed no statistically significant causal association between various types of abortion and EMS. Specifically, the odds ratios (ORs) were as follows: medical abortion (OR 0.96, 95% CI: 0.78-1.18, p = 0.72), spontaneous abortion (OR 0.99, 95% CI: 0.81-1.21, p = 0.92), and other types of abortions (OR 1.01, 95% CI: 0.99-1.03, p = 0.36), indicating no significant effects on the risk of EMS. Similarly, analysis in the reverse direction showed no significant causal effects of EMS on the likelihood of experiencing any type of abortion, with ORs for medical abortion (0.97, 95% CI: 0.91-1.03, p = 0.33), spontaneous abortion (0.98, 95% CI: 0.92-1.04, p = 0.50), and other abortions (1.30, 95% CI: 0.76-2.23, p = 0.34). Sensitivity analyses supported these findings, demonstrating no evidence of horizontal pleiotropy or significant heterogeneity.

CONCLUSION

Our MR results do not support a causal relationship between abortion and EMS.

Protopanaxadiol improves endometriosis associated infertility and miscarriage in sex hormones receptors-dependent and independent manners

Background: Patients with endometriosis (EMs) have high risks of infertility and spontaneous abortion. How to remodel the fertility of patients with EMs has always been the hot spot and difficulty in the field of reproductive medicine. As an aglycone of ginsenosides, protopanaxadiol (PPD) possesses pleiotropic biological functions and has high medicinal values. We aimed to investigate the effect and potential mechanism of PPD in the treatment of EMs-associated infertility and spontaneous abortion.

Methods: The EMs mice models were constructed by allotransplantation. The pregnancy rates, embryo implantation numbers and embryo resorption rates of control and EMs were counted. RNA sequencing, qRT-PCR, enzyme linked immunosorbent assay (ELISA) and FCM analysis were performed to screen and confirm the expression of endometrial receptivity/decidualization-related molecules, inflammation cytokines and NK cell function-related molecules in vitro and/or in vivo. The SWISS Target Prediction, STRING and Cytoscape were carried out to predict the potential cellular sensory proteins, the protein-protein interaction (PPI) network between sensory proteins and fertility-related molecules, respectively. Micro-CT detection, liver and kidney function tests were used to evaluate the safety.

Results: Here, we observe that PPD significantly up-regulates endometrial receptivity-related molecules (e.g., Lif, Igfbp1, Mmps, collagens) and restricts pelvic inflammatory response (low levels of IL-12 and IFN-γ) of macrophage, and further remodel and improve the fertility of EMs mice. Additionally, PPD increases the expression of decidualization-related genes and Collagens, and promotes the proliferation, residence, immune tolerance and anagogic functions of decidual NK cells (low levels of CD16 and NKp30, high levels of Ki67, VEGF, TGF-β) in pregnant EMs mice, and further triggers decidualization, decidual NK cell-mediated maternal-fetal immune tolerance and angiogenesis, preventing pregnant EMs mice from miscarriage. Mechanically, these effects should be dependent on ESRs, PGR and other sensory proteins (e.g., AR). Compared with GnRHa (the clinic first-line drug for EMs), PPD does not lead to the decline of serum estrogen and bone loss.

Conclusion: These data suggest that PPD prevents EMs-associated infertility and miscarriage in sex hormones receptors-dependent and independent manners possibly, and provides a potential therapeutic strategy with high efficiency and low side effects to remodels the fertility of patients with EMs.