野田 佳照

Objectives: Alterations in the vaginal bacterial flora reflect the status of various obstetric conditions and are associated with mechanisms that underlie certain pregnancy-associated complications. These changes are also a predictive biomarker for clinical outcomes of these adverse events. Methods: We examined the vaginal microbiome in samples from pregnant Japanese women with preterm labor. Results: The microbiota composition in preterm delivery (PD) samples differed from those of control or threatened preterm delivery (TPD) samples in principal component analysis. An increase in Firmicutes and a decrease in Actinobacteria were significantly associated with PD only (both P<0.01). In the Firmicutes phylum, Lactobacillus tended to be abundant, and the abundance of L. iners and L. crispatus was especially high, whereas the L. gasseri population was low in PD samples. Longitudinal analysis showed that the abundance of L. iners decreased after commencing tocolytic treatment in TPD samples compared with before treatment, but it remained high in PD samples. Conclusions: The vaginal microbiome may be a useful prognostic indicator of preterm labor and a monitoring tool for tocolytic treatment to prevent preterm birth.

OBJECTIVE: The proprotein convertase furin is known to be involved in the processing of pro-B-type natriuretic peptide (proBNP) and prorenin receptor (PRR), suggesting that it has a potential function in blood pressure regulation. We investigated the role of furin in the etiology of pre-eclampsia and its related disorder, unexplained fetal growth restriction (FGR) without hypertension. METHODS: We evaluated serum and placental furin levels in pre-eclampsia, FGR and uncomplicated pregnancy. Additionally, we investigated the correlation between the serum furin levels and products of furin enzymatic activity or clinical parameters. RESULTS: We demonstrated that the maternal circulation in cases of pre-eclampsia and FGR had lower levels of soluble furin than uncomplicated pregnancies. Both NT-proBNP and soluble PRR were elevated in pre-eclampsia, whereas only soluble PRR was at higher levels in unexplained FGR. Linear regression analysis revealed a negative correlation between the serum furin level and that of NT-proBNP or soluble PRR. While we observed that the serum furin or soluble PRR level correlated with blood pressure, a stronger correlation was observed with birth and placental weights. Further to this, the FURIN mRNA levels were significantly reduced in placental pre-eclamptic placentas as well as in FGR cases. CONCLUSION: These data suggest the possibility that reduced levels of furin may be the result of a negative feedback from the activation of the renin-angiotensin pathway that leads to feto-placental dysfunction with or without maternal hypertension. This may represent an etiologic pathway of pre-eclampsia and unexplained FGR.

BACKGROUND: Soluble fms-like tyrosine kinase 1 (sFlt-1) is believed to be a prominent component in the pathogenesis of pre-eclampsia, although the precise etiology has remained elusive. In this study, the etiological role of FLT1 variant was further validated in pre-eclampsia by examining this association in a Japanese sample population. METHODS: The genotypes of three variants (rs4769613, rs12050029 and rs149427560) were examined in the upstream region of the FLT1 gene in placentas from pre-eclamptic (n=47) or normotensive control (n=49) pregnancy samples. Additionally, FLT1 mRNA levels in placenta were determined by qRT-PCR. ELISA was further used to detect circulating sFlt-1 levels in maternal sera. The intergroup comparisons were made using the Mann-Whitney U test or one way analysis of variance and P values of less than 0.05 were considered statistically significant. RESULTS: First, the rs4769613 (C>T) and rs12050029 (G>A) genotypes were examined in placentas but no significant differences were found in the genotype or allele-type frequencies. Next, nearby short tandem repeat, rs149427560, was examined which manifested four size variants. In the genotypewise analysis, the frequency of the 474/476 heterozygote was significantly lower in pre-eclampsia (p<0.05). As expected, the FLT1 mRNA levels were significantly elevated in the pre-eclamptic placentas and sFlt-1 was higher in pre-eclamptic maternal sera. However, the genotype of these variants did not affect the FLT1 mRNA or serum sFlt-1 levels. CONCLUSION: Our findings did not support the hypothesis that genetic variations around the FLT1 gene affect the subtle expression changes underlying the etiologic pathway of pre-eclampsia. The hypothesis deserves further investigation through a larger sample size.

BACKGROUND: Nectins are cell adhesion molecules that play a pivotal role in adherens junctions and tight junctions. Our previous study using whole-genome oligonucleotide microarrays revealed that nectin-4 was upregulated in pre-eclamptic placentas. We investigated the role of nectin-4 in the etiology of pre-eclampsia. METHODS: We investigated the expression of nectin-4 using real-time RT-PCR, western blot and immunostaining. Additionally, we performed matrigel invasion assay and cytotoxicity assay using cells overexpressing the nectin-4. RESULTS: NECTIN4 transcripts were elevated in pre-eclamptic placentas relative to uncomplicated pregnancies. Nectin-4 protein levels in pre-eclamptic placentas were higher on a semi-quantitative western blot. Nectin-4 was localized at the apical cell membrane in syncytiotrophoblast cells and not at the adherens junctions. Nectin-4 was also detected in cytotrophoblasts and a subset of cells in the decidua. Nectin-4 overexpressing trophoblast cells migrated normally in the matrix. However, Natural killer (NK) cells showed a strong cytotoxic effect against nectin-4 overexpressing trophoblast cells. No causative genetic variation was evident in the NECTIN4 gene from a pre-eclamptic placenta. CONCLUSIONS: There are as yet unknown factors that induce nectin-4 overexpression in trophoblast cells that may contribute to abnormal placentation via an aberrant immune response and the onset of a pre-eclamptic pregnancy.