Hiroshi Suginami

Expression and localization of aminopeptidase N, neutral endopeptidase, and dipeptidyl peptidase IV in the human placenta and fetal membranes

OBJECTIVE Our purpose was to determine the distribution of membrane-bound cell surface peptidases, namely aminopeptidase N, neutral endopeptidase, and dipeptidyl peptidase IV in the human placenta and fetal membranes. STUDY DESIGN Frozen tissue sections of the first-trimester chorionic villi, term placentas, and term fetal membranes were stained by indirect immunofluorescence with specific monoclonal antibodies. RESULTS In the first trimester chorionic villi cytotrophoblasts expressed both neutral endopeptidase and dipeptidyl peptidase IV, but syncytiotrophoblasts expressed only neutral endopeptidase. Stromal cells in the chorionic villi expressed the three peptidases at various intensities. In the term placentas villous syncytiotrophoblasts expressed neutral endopeptidase weakly, and the villous stromal cells expressed large amounts of both aminopeptidase N and dipeptidyl peptidase IV but neutral endopeptidase weakly or faintly. In the term fetal membranes amniotic epithelial cells and chorion laeve expressed both neutral endopeptidase and dipeptidyl peptidase IV. Decidual cells in the decidua parietalis moderately or highly expressed aminopeptidase N. CONCLUSION Three peptidases, aminopeptidase N, neutral endopeptidase, and dipeptidyl peptidase IV, are expressed by different cell populations in the human placenta and fetal membranes, suggesting their respective and important roles at the maternofetal interface.

Physiological Roles of Integrin α6β1 in Ovarian Functions

We previously reported that human ovarian cells express integrin β1 families. The physiological role(s) of integrins was investigated using in vitro human granulosa cell culture and in vivo mouse ovulation model. In human luteinizing granulosa cell culture obtained from the patients undergoing in vitro fertilization treatment, laminin, which is a ligand for integrin α6β1, suppressed the production of progesterone by granulosa cells. On the other hand, the anti-α6 monoclonal antibody (mAb) GoH3, which partially inhibits the interaction between integrin α6β1 and laminin, enhanced production of progesterone by 2-fold of the control under the culture with laminin, indicating that integrin α6β1 regulates the luteinization of human granulosa cell during the periovulatory phase. In an immature superovulated 13-day-old ICR (CD-1) mice model, intraperitoneal administration of GoH3 induced successful ovulation, whereas no ovulation was observed in the GoH3-nontreated groups, showing that integrin α6β1 is related to gonadotropin-induced follicular growth. These findings suggest that the interaction between integrin α6β1 and laminin plays an important role in the corpus luteum formation and follicular growth.

Cell Adhesion and Reproduction

Cell adhesion is essential for the regulation of many cellular functions. The adhesion molecule plays a critical role as a fundamental substance in various processes of reproduction such as trophoblast-endometrial interaction. Our understanding of the physiology of adhesion molecules will be helpful for clinical application of these molecules in the treatment and assessment of disorders of many processes of reproduction. We will briefly review integrins, cadherins, and laminin, which were the principal subjects of discussion in this conference.

An aminopeptidase inhibitor, bestatin, enhances progesterone and oestradiol secretion by porcine granulosa cells stimulated with follicle stimulating hormone in vitro

We examined the presence of cell surface aminopeptidase on cultured porcine granulosa cells by employing the aminopeptidase assay using alanine-p-nitroanilide and histochemical staining using L-leucyl-beta-naphthylamide. Porcine granulosa cells obtained from follicles 4-5 mm in diameter were cultured for 7 days. The aminopeptidase assay showed that the porcine granulosa cell culture had aminopeptidase activity and that this activity was inhibited in a dose-dependent manner by bestatin which binds to cell surfaces and inhibits cell surface aminopeptidases. Histochemical staining also indicated that cultured granulosa cells had aminopeptidase activity. Porcine granulosa cells were cultured in the presence or absence of porcine follicle stimulating hormone (FSH, 3.125 nmol/l) and/or bestatin (0.4, 4.0 and 40.0 micrograms/ml) for 7 days, and the production of progesterone and oestradiol was measured. In the presence of porcine FSH, the production of progesterone and oestradiol by granulosa cells was increased significantly by approximately 5- and 2-fold respectively. These increases were enhanced further by bestatin (40.0 micrograms/ml). In the absence of porcine FSH, progesterone production was enhanced by bestatin (40.0 micrograms/ml), whereas no significant effect of bestatin on oestradiol secretion was observed. These findings indicate that the inhibition of membrane-bound aminopeptidase(s) on the cell surfaces affects the steroidogenesis of granulosa cells, and that these aminopeptidase(s) are important regulators of granulosa cell differentiation.

Complete Removal of Endometriosis Improves Fecundity

Endometriosis is one of the causative factors of impaired fecundity. Whatever the mechanisms are of this impairment, surgical removal of endometriosis appears to increase postoperative fecundity. Our strategy in laparoscopic surgery for symptomatic endometriosis is to completely remove endometriosis. However, despite this strategy, laparoscopic surgery nonetheless creates two categories of patients; complete and incomplete surgery groups. We found by comparing the two groups that both were comparable in terms of fecundity during the early postoperative phase, whereas unlike the complete surgery group, fecundity in the incomplete surgery group stayed low during the late postoperative phase. Deep rectal endometriosis and deeply invading pelvic endometriosis are conditions wherein complete removal of endometriosis is difficult. We have developed laparoscopic surgeries for these conditions: laparoscopic anterior rectum slicing (LARS) and laparoscopic pelvic wall slicing (LPWS) operations, respectively. Both operations are effective in alleviating disease-related symptoms with minimal surgical invasiveness.

Granulosa Cells Express Integrin α6: Possible Involvement of Integrin α6 in Folliculogenesis

To identify differentiation antigens of granulosa cells, we have raised two monoclonal antibodies against porcine granulosa cells (POG-2 antibody) and human granulosa cells (OG-1 antibody). Analysis of N-terminal amino acid sequences of purified OG-1 and POG-2 antigens revealed that they were identical to human integrin α6 and its porcine homolog, respectively. An immunohistochemical study showed that integrin α6 was highly expressed on granulosa cells in preovulatory follicles in the human ovary, whereas it was highly expressed on granulosa cells in small follicles in the porcine ovary. As a common characteristic of integrin α6 expression in both ovaries, granulosa cells located in inner layers, which are not in contact with the basal lamina, expressed integrin α6 on the cell surface. This expression profile suggests that the interaction between integrin and extracellular matrices occurs in the granulosa cells located in inner layers. This cell surface interaction is reported to modulate soluble signals to the cells. Since the expression of integrin α6 on inner-layer granulosa cells is related to stages of differentiation, this interaction may be involved in folliculogenesis.

Laparoscopic Surgery for Endometriosis: A Long Term Follow‐Up

Objective: To investigate if complete resolution of endometriosis by laparoscopic surgery is beneficial to postoperative fecundity, dysmenorrhea and dyspareunia.

Unusual uterus didelphys presenting in the retroperitoneum

We describe a case of uterus didelphys with obstructed hemivagina and ipsilateral renal agenesis. Magnetic resonance imaging (MRI) demonstrated uterus didelphys and laparoscopy revealed that an affected uterus was present in the retroperitoneum.