Minako Koizumi

Increased risk of placenta previa is associated with endometriosis and tubal factor infertility in assisted reproductive technology pregnancy

Although assisted reproductive technology (ART) is suspected to increase the risk of placenta previa, a life-threatening complication of pregnancy, the reason is poorly understood. We recruited consecutive 318 pregnancies conceived by ART in our clinic and examined relation of ten variables, i.e. maternal age, gravidity, parity, male or female fetus, previous abortion, previous cesarean delivery, endometriosis, ovulatory disorder, tubal disease, and male infertility, to placenta previa, by logistic regression analysis. As a result, we found that endometriosis (odds ratio = 15.1; 95% CI = 7.6–500.0) and tubal disease (odds ratio = 4.4; 95% CI = 1.1–26.3) were significantly associated with placenta previa. It would be preferable to take the increased risk of placenta previa into account in treating ART pregnancy with endometriosis and tubal disease.

Expression of retinoic acid-related orphan receptor alpha and its responsive genes in human endometrium regulated by cholesterol sulfate.

Cholesterol sulfate (CS) is a major sterol sulfate in human plasma that is detected in the uterine endometrium. CS plays a role in steroidogenesis, cellular membrane stabilization, and regulation of the skin barrier. We previously reported that CS increased in rabbit endometrium during the implantation period. Recently, CS has been reported to be a ligand of retinoic acid receptor-related orphan receptor alpha (RORA). NR1D1 is one of the genes regulated by RORA. In the present study, we investigated the regulation of RORA and NR1D1 by CS in human endometrium. We determined the association-dissociation curves for the interaction of CS with RORA and the kinetic rates by surface plasmon resonance. Immunohistochemical staining and in situ hybridization revealed that RORA and NR1D1 were expressed in human endometrial stromal and epithelial cells. CS treatment significantly induced the mRNA expression of RORA and NR1D1 mRNA in ESCs. The results of a luciferase assay showed that RORA significantly activated the human NR1D1 promoter regardless of CS. Our results suggest that CS regulates the expression of RORA responsive genes in human endometrial cells but not as a ligand for RORA.

Inhibition of proteases involved in embryo implantation by cholesterol sulfate

BACKGROUND Matrix metalloproteinases (MMPs) and the plasminogen activator (PA)/plasmin system are two major groups of proteases involved in the matrix degradation required for embryo implantation. We previously showed that the content of cholesterol sulfate (CS) in rabbit endometrium increases characteristically during the implantation period. Furthermore, CS has been reported to inhibit serine proteases. In this study, we investigated whether CS can regulate the activity of proteases in cultured human endometrial stromal cells. METHODS AND RESULTS CS (1-30 microM) and plasminogen (precursor of plasmin) were added to the culture media of human endometrial stromal cells and incubated for 24 h. Culture media were collected for analysis of plasmin and MMP-2, -3 and -9 enzyme activities using fluorescence assays. Plasmin and MMP-3 activities were significantly reduced by CS in a dose-dependent manner (P < 0.001). Western blot analysis of the culture media revealed that CS inhibited the conversion by plasmin of MMP-3 from the precursor form to the active form. Fluorescence assay using a common substrate of MMP-2 and MMP-9 showed that enzymatic activity remains at approximately 50%, even at 30 microM CS. Gelatin zymography demonstrated that CS inhibited the activation of MMP-9 but not MMP-2 from the precursor, suggesting that the activation of MMP-2 may be independent of plasmin. CONCLUSIONS CS inhibits not only plasmin activity but also MMP activities indirectly by inhibiting the plasmin-mediated process. These findings suggest that CS may be an important regulator of proteolysis during trophoblast invasion.

Inhibition of cell invasion and protease activity by cholesterol sulfate

We demonstrated that cholesterol sulfate (CS) inhibits invasion of a trophoblast cell line and plasmin enzyme activity in a noncompetitive manner by binding to the enzyme itself, suggesting that CS can repress cell invasion by inhibiting proteinases such as those involved in the plasminogen activator/plasmin system. Considering these results, it is possible that CS may act as a signaling molecule between the trophoblast and endometrium, and may regulate the process of implantation.

The progesterone-responsive gene 14-3-3τ enhances the transcriptional activity of progesterone receptor in uterine cells

Members of the 14-3-3 family are intracellular dimeric phosphoserine-binding proteins that can associate with and modulate the activities of many proteins. In our efforts to isolate the genes regulated by progesterone (P(4)) using suppressive subtractive hybridization, we previously found that 14-3-3τ is one of the genes upregulated by P(4). In this study, we demonstrated by quantitative RT-PCR (qRT-PCR), western blot analyses, and immunohistochemistry that 14-3-3τ mRNA and protein levels were increased in the rat uterus after P(4) treatment. Furthermore, qRT-PCR indicated that P(4) increased 14-3-3τ mRNA levels in human endometrial epithelial cells and endometrial stromal cells (ESCs). Western blot and qRT-PCR analyses revealed that in vitro decidualization using cAMP and medroxyprogesterone 17-acetate increased levels of 14-3-3τ mRNA and protein in ESCs. We have shown by qRT-PCR and western blot analyses that P(4) increased the mRNA and protein levels of 14-3-3τ in Ishikawa cells that stably express P(4) receptor-B (PR-B). Immunocytochemistry revealed that 14-3-3τ colocalizes with PR and translocates from the cytoplasm to the nucleus in response to P(4). Moreover, by luciferase reporter assay, we demonstrated that 14-3-3τ enhances the transcriptional activity of PR-B. Taken together, we propose that 14-3-3τ is a P(4)-responsive gene in uterine cells that modulates P(4) signaling.

Successful pregnancy following low-dose hCG administration in addition to hMG in a patient with hypothalamic amenorrhea due to weight loss

We describe successful ovulation induction with low-dose hCG administration in addition to hMG in a patient with refractory hypothalamic amenorrhea. A 24-year-old woman with weight loss-related amenorrhea underwent ovulation induction and intracytoplasmic sperm injection (ICSI). Administration of exogenous gonadotropins was ineffective in ovulation induction. Supplementation with low-dose hCG in order to increase luteinizing hormone (LH) activity in the late follicular phase produced late folliculogenesis and steroidogenesis, and ovulation was then successfully induced. This report reacknowledges the critical role that LH plays cooperatively with follicle-stimulating hormone in both folliculogenesis and steroidogenesis.