RESUMEN
Background: Recurrent pregnancy loss refers to the spontaneous demise of two or more pregnancies before the 24 weeks of gestation. In almost half of the cases of recurrent miscarriages, the causes remain unknown since there is no reliable way of prognosis, early diagnosis, or treatment. Recent research has detected differential expression of certain miRNAs in reproductive system pathologies. Methods: The aim of the present review is to focus on microRNAs and their relationship with idiopathic recurrent miscarriages and to correlate miRNA expression with recurrent miscarriage and examine their potential role as biomarkers. Pubmed/Medline and Scopus databases were searched up to 31st January 2024 with terms related to recurrent pregnancy loss and miRNAs. Results: In total, 21 studies were selected for the review. A total of 75 different miRNAs were identified, showing a statistically significant differential expression. Around 40 miRNAs had increased expression, such as miR-520, miR-184 and miR-100-5p, 21 decreased, such as let-7c, and 14 had either increased or decreased expression depending on the study, such as miR-21. Conclusions: The dysregulation of miRNA expression is strongly associated with recurrent miscarriages. The circulating in the peripheral blood miRNAs, miR-100-5p and let-7c, might be utilized as biomarkers and establish a valuable non-invasive prognostic and diagnostic tool in the future.
RESUMEN
Recurrent implantation failure (RIF) poses a significant challenge in assisted reproductive technology (ART) outcomes. The endometrium plays a crucial role in embryo implantation, and its protein expression profile is integral in determining receptivity. Proteomics has emerged as a valuable tool in unraveling the molecular intricacies underlying endometrial receptivity and RIF. The aim of the present review is to analyze the contribution of proteomics to the understanding of endometrial protein expression in women with RIF, based on the results of significant proteomic studies. Medline/Pubmed databases were searched using keywords pertaining to proteomics combined with terms related to RIF. 15 studies were included in the present review. Several proteins have been found to exbibit differential expression in endometrial biopsies and fluid samples between fertile women and women with RIF during the receptive endometrial phase. The profile of endometrial proteins varied significantly among the studies. Nevertheless, similar changes in the expression levels of annexin-6, progesterone receptor, MMP-2, and MMP-9 in the endometrium of women with RIF, were found in more than one study indicating that certain proteins could potentially be effective biomarkers of endometrial receptivity. Proteomics contributes significantly to the understanding of protein expression in the endometrium of women with RIF and the analysis of proteins in endometrial fluid are promising for improving the clinical management of RIF.
