Hyposecretion of cervical MUC5B is related to preterm birth in pregnant women after cervical excisional surgery.

PROBLEM: Excisional surgery for cervical intraepithelial neoplasia is a risk factor for preterm birth in subsequent pregnancies. However, the underlying mechanisms of this association remain unclear. We previously showed that cervical MUC5B, a mucin protein, may be a barrier to ascending pathogens during pregnancy. We thus hypothesized that hyposecretion of cervical MUC5B is associated with preterm birth after cervical excisional surgery. METHOD OF STUDY: This prospective nested case-control study (Study 1) included pregnant women who had previously undergone cervical excisional surgery across 11 hospitals. We used proteomics to compare cervicovaginal fluid at 18-22 weeks of gestation between the preterm and term birth groups. In another case-control analysis (Study 2), we compared MUC5B expression in nonpregnant uterine tissues between 15 women with a history of cervical excisional surgery and 26 women without a history of cervical surgery. RESULTS: The abundance of MUC5B in cervicovaginal fluid was significantly decreased in the preterm birth group (fold change = 0.41, p = .035). Among the 480 quantified proteins, MUC5B had the second highest positive correlation with gestational age at delivery in the combined preterm and term groups. The cervicovaginal microbiome composition was not significantly different between the two groups. Cervical length was not correlated with gestational age at delivery (r = 0.18, p = .079). Histologically, the MUC5B-positive area in the nonpregnant cervix was significantly decreased in women with a history of cervical excisional surgery (0.85-fold, p = .048). The distribution of MUC5B-positive areas in the cervical tissues of 26 women without a history of cervical excisional surgery differed across individuals. CONCLUSIONS: This study suggests that the primary mechanism by which cervical excisional surgery causes preterm birth is the hyposecretion of MUC5B due to loss of the cervical glands.

Shear stress in the intervillous space promotes syncytial formation of iPS cells-derived trophoblasts†.

The intervillous space of human placenta is filled with maternal blood, and villous trophoblasts are constantly exposed to the shear stress generated by maternal blood pressure and flow throughout the entire gestation period. However, the effects of shear stress on villous trophoblasts and their biological significance remain unknown. Here, using our recently established naïve human pluripotent stem cells-derived cytotrophoblast stem cells (nCTs) and a device that can apply arbitrary shear stress to cells, we investigated the impact of shear stress on early-stage trophoblasts. After 72 h of exposure to 10 dyn/cm2 shear stress, nCTs became fused and multinuclear, and mRNA expression of the syncytiotrophoblast (ST) markers, such as glial cell missing 1, endogenous retrovirus group W member 1 envelope, chorionic gonadotropin subunit beta 3, syndecan 1, pregnancy specific beta-1-glycoprotein 3, placental growth factor, and solute carrier family 2 member 1 were significantly upregulated compared to static conditions. Immunohistochemistry showed that shear stress increased fusion index, human chorionic gonadotropin secretion, and human placental lactogen secretion. Increased microvilli formation on the surface of nCTs under flow conditions was detected using scanning electron microscopy. Intracellular cyclic adenosine monophosphate significantly increased under flow conditions. Moreover, transcriptome analysis of nCTs subjected to shear stress revealed that shear stress upregulated ST-specific genes and downregulated CT-specific genes. Collectively, these findings indicate that shear stress promotes the differentiation of nCTs into ST.

Cervical MUC5B and MUC5AC are Barriers to Ascending Pathogens During Pregnancy.

CONTEXT: Cervical excision is a risk factor for preterm birth. This suggests that the cervix plays an essential role in the maintenance of pregnancy. OBJECTIVE: We investigated the role of the cervix through proteomic analysis of cervicovaginal fluid (CVF) from pregnant women after trachelectomy surgery, the natural model of a lack of cervix. METHODS: The proteome compositions of CVF in pregnant women after trachelectomy were compared with those in control pregnant women by liquid chromatography-tandem mass spectrometry and label-free relative quantification. MUC5B/AC expression in the human and murine cervices was analyzed by immunohistochemistry. Regulation of MUC5B/AC expression by sex steroids was assessed in primary human cervical epithelial cells. In a pregnant mouse model of ascending infection, Escherichia coli or phosphate-buffered saline was inoculated into the vagina at 16.5 dpc, and the cervices were collected at 17.5 dpc. RESULTS: The expression of MUC5B/5AC in cervicovaginal fluid was decreased in pregnant women after trachelectomy concomitant with the anatomical loss of cervical glands. Post-trachelectomy women delivered at term when MUC5B/AC abundance was greater than the mean normalized abundance of the control. MUC5B levels in the cervix were increased during pregnancy in both humans and mice. MUC5B mRNA was increased by addition of estradiol in human cervical epithelial cells, whereas MUC5AC was not. In a pregnant mouse model of ascending infection, E. coli was trapped in the MUC5B/AC-expressing mucin of the cervix, and neutrophils were colocalized there. CONCLUSION: Endocervical MUC5B and MUC5AC may be barriers to ascending pathogens during pregnancy.

Fetal macrophages assist in the repair of ruptured amnion through the induction of epithelial-mesenchymal transition.

The premature rupture of the amniotic sac, a condition referred to as a preterm prelabor rupture of membranes (pPROM), is a leading cause of preterm birth. In some cases, these ruptured membranes heal spontaneously. Here, we investigated repair mechanisms of the amnion, a layer of epithelial cells in the amniotic sac closest to the embryo. Macrophages migrated to and resided at rupture sites in both human and mouse amnion. A process called epithelial-mesenchymal transition (EMT), in which epithelial cells acquire a mesenchymal phenotype and which is implicated in tissue repair, was observed at rupture sites. In dams bearing macrophage-depleted fetuses, the repair of amnion ruptures was compromised, and EMT was rarely detected at rupture sites. The migration of cultured amnion epithelial cells in wound healing assays was mediated by EMT through transforming growth factor-ß (TGF-ß)-Smad signaling. These findings suggest that fetal macrophages are crucial in amnion repair because of their ability to induce EMT in amnion epithelial cells.

Three-dimensional human placenta-like bud synthesized from induced pluripotent stem cells.

Placental dysfunction is related to the pathogenesis of preeclampsia and fetal growth restriction, but there is no effective treatment for it. Recently, various functional three-dimensional organs have been generated from human induced-pluripotent cells (iPSCs), and the transplantation of these iPSCs-derived organs has alleviated liver failure or diabetes mellitus in mouse models. Here we successfully generated a three-dimensional placental organ bud from human iPSCs. The iPSCs differentiated into various lineages of trophoblasts such as cytotrophoblast-like, syncytiotrophoblast-like, and extravillous trophoblast-like cells, forming organized layers in the bud. Placental buds were transplanted to the murine uterus, where 22% of the buds were successfully engrafted. These iPSC-derived placental organ buds could serve as a new model for the study of placental function and pathology.

Power morcellation-induced dissemination of sarcomatous component arising in leiomyoma.

In 2014, the US Food and Drug Administration issued a safety communication warning against the use of power morcellators during laparoscopic hysterectomy or myomectomy. We report a case of peritoneal leiomyosarcomatosis attributable to power morcellation. A 49-year-old nulligravid woman presented with a huge uterine tumor measuring 15 × 8 cm that was diagnosed as benign leiomyoma on magnetic resonance imaging. The uterine tumor had shrunk to 13 × 7 cm after five treatment courses with a gonadotropin-releasing hormone agonist. She underwent laparoscopic hysterectomy using power morcellation; postoperative pathological diagnosis was benign leiomyoma. After 6 months, urinary ascites developed because of right ureteral rupture. She underwent laparotomy and was diagnosed with peritoneal leiomyosarcomatosis. Meticulous and thorough reevaluation of the morcellated specimens revealed a small component of leiomyosarcoma. Use of power morcellation should be minimized until the advent of novel methods that can perfectly differentiate benign from malignant uterine tumors preoperatively.