Beyond Immune Balance: The Pivotal Role of Decidual Regulatory T Cells in Unexplained Recurrent Spontaneous Abortion.

Recurrent spontaneous abortion (RSA) is defined as two or more consecutive pregnancy failures, which brings tremendous stress to women of childbearing age and seriously affects family well-being. However, the reason in about 50% of cases remains unknown and is defined as unexplained recurrent spontaneous abortion (URSA). The immunological perspective in URSA has attracted widespread attention in recent years. The embryo is regarded as a semi-allogeneic graft to the mother. A successful pregnancy requires transition to an immune environment conducive to embryo survival at the maternal-fetal interface. As an important member of regulatory immunity, regulatory T (Treg) cells play a key role in regulating immune tolerance at the maternal-fetal interface. This review will focus on the phenotypic plasticity and lineage stability of Treg cells to illustrate its relationship with URSA.

Decidual macrophages in recurrent spontaneous abortion.

Recurrent spontaneous abortion (RSA) is defined as two or more pregnancy loss, affecting the happiness index of fertility couples. The mechanisms involved in the occurrence of RSA are not clear to date. The primary problem for the maternal immune system is how to establish and maintain the immune tolerance to the semi-allogeneic fetuses. During the pregnancy, decidual macrophages mainly play an important role in the immunologic dialogue. The purpose of this study is to explore decidual macrophages, and to understand whether there is a connection between these cells and RSA by analyzing their phenotypes and functions. Pubmed, Web of Science and Embase were searched. The eligibility criterion for this review was evaluating the literature about the pregnancy and macrophages. Any disagreement between the authors was resolved upon discussion and if required by the judgment of the corresponding author. We summarized the latest views on the phenotype, function and dysfunction of decidual macrophages to illuminate its relationship with RSA.

[Capability of oocyte maturation in human cryopreserved ovarian tissue following xenografting].

OBJECTIVE: To investigate the development and maturation competence of oocytes retrieved from cryopreserved and transplanted human fetal ovarian tissue by techniques of tissue culture, inducing ovary, oocyte retrieval, and in vitro maturation (IVM). METHODS: Fetal ovaries of 20 weeks were frozen-thawed and cultured for 6 days in vitro, then xenografted into kidney capsules of immunodeficient mice. All mice were stimulated with follicle stimulating hormone every second day for 23 weeks, starting 1 week after grafting. Then oocytes were retrieved from antral follicles 13 hours after human chorionic gonadotrophin injection. IVM was performed to evaluate the maturation competence of the oocytes from ovarian grafts. Human fetal ovarian tissues were examined with histological and proliferating cell nuclear antigen (PCNA) evaluation. RESULTS: There was no difference between fresh ovarian tissues and frozen-thawed ovarian tissues in the percentage of follicles at different growth stages (P > 0.05). The proportion of the primary follicles and preantral follicles in the cultured ovarian tissues was significantly larger than that of fresh ovarian tissues and frozen-thawed ovarian tissues (P < 0.05). The proportion of the primary follicles, preantral follicles, and antral follicles in the transplanted ovarian tissues was significantly higher than that of cultured ovarian tissues, fresh ovarian tissues, and frozen-thawed ovarian tissues (P < 0.05). No significant signals of PCNA in the primordial follicles in all ovarian tissues were observed. PCNA immunoreactivity first appeared in primary follicles. However, the obviously positive signals of PCNA were seen in the oocytes and/or the granular cells of cultured ovarian tissues and transplanted ovarian tissues. Oocytes from antral follicles were collected and matured in vitro, and 21.43% of the oocytes reached to MII within 48 hours IVM. CONCLUSIONS: Human ovarian follicles can survive and develop well after cryopreservation, tissue culture, and xenotransplantation. Furthermore, oocytes recovered from grafts have normal maturation competence.