microRNAs (miRNAs) play a critical role in implantation and development of mouse embryos. In this study, we aim to evaluate the possibility of miRNAs as potential biomarkers in the blastocyst culture to assess embryo quality. We also intend to investigate whether improved clinical outcomes of vitrified embryos agree with altered miRNA expressions. Mouse embryos from in vitro fertilization were vitrified at the two-cell stage. After thawing, the embryos were individually cultured and developed to the blastocyst stage. We used quantitative real-time polymerase chain reaction to evaluate miRNA expression levels in both vitrified and fresh groups, and culture medium (CM). The fibronectin binding assay was performed to examine for blastocyst attachment.The findings showed reduced expressions of miR-16-1 (0.2 ± 0.06) and miR-Let-7a (0.65 ± 0.1) after vitrification compared to fresh embryos. We observed significant upregulation of the target genes Vav3 (4.33 ± 0.25), integrin β-3 (Itg β3; 4.73 ± 0.2), and Bcl2 (2.29 ± 0.16) in the vitrified embryos compared to the fresh groups. Evaluation of blastocyst CM showed upregulation of miR-Let-7a (15.68 ± 0.89), miR-16-1 (16.18 ± 0.75), and miR-15a (13.36 ± 0.73) in the vitrified group in comparison to the fresh blastocysts (P < .05). The expression levels of miR-16-1 (3.28 ± 0.63), miR-15a (5.91 ± 0.38), and miR-Let-7a (9.07 ± 0.6) in CM of the vitrified blastocysts conducted on fibronectin were significantly higher than the fresh group (P < .05).This study showed that vitrification of embryos changes implantation and proliferation biomarkers. In addition, upregulated miRNAs in CM could be potentially used for noninvasive early assessment of embryo quality.

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2), was declared a global pandemic in March 2020 and resulted in more than 6 million deaths worldwide to date. Although several vaccines were produced against COVID-19 and many therapeutic protocols were developed for the management of this respiratory infection, COVID-19 pandemic has still remained an unresolved problem with the emergence of new variants of SARS-CoV-2, especially vaccine-resistant variants. Probably, end of the COVID-19 needs effective and certain treatments which were undiscovered to date. According to immunomodulatory and regenerative properties, mesenchymal stem cells (MSCs) have been considered a therapeutic approach to suppressing cytokine storm caused by SARS-CoV-2 and the treatmet of severe COVID-19. Following intravenous (IV) infusion of MSCs, cells entrap in the lung, guard alveolar epithelial cells, suppress pulmonary fibrosis and improve lung dysfunction. The human menstrual blood-derived stem cells (hMenSCs) as a novel source of MSCs are collected by noninvasive, painless, and easy way without ethical issues. MenScs are an abundant and cheap source with a high proliferation rate and differentiation ability into multiple cell lineages. Regarding immunomodulatory and anti-inflammatory properties, regenerative ability and low immunogenicity, these cells exhibit great potential in the treatment of various diseases. Some clinical trial studies have begun using MenSCs to treat severe COVID-19. According to these trials, MenSC therapy showed promising and encouraging results in treating severe COVID-19. We reviewed published clinical trials and summarized the effects of MenSC therapy on severe COVID-19 with a focus on clinical and laboratory data, immune and inflammatory factors and concluded the advantages and possible risks of this procedure.

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