Tamotsu Kiya

Lysyl Oxidase and MMP-2 Expression in Dehydroepiandrosterone-Induced Polycystic Ovary in Rats

Abstract Polycystic ovary syndrome (PCOS) is characterized by cystogenesis; however, the cause of this cystogenesis is unknown. At ovulation, preovulatory collagenolytic activities in the ovarian follicles increase and various proteinases are needed to degrade the tissues surrounding the follicles. To clarify the roles of enzymes in collagen degradation of the follicular wall of polycystic ovary (PCO) in relation to the cystogenesis, we examined expression of lysyl oxidase (LOX), which initiates cross-link formation of the collagen and elastin in the extracellular matrix, and expression of matrix metalloproteinases (MMPs) in ovaries of model rats with PCO induced by dehydroepiandrosterone (DHEA) compared with MMP expression in control rats. DHEA treatment increased LOX mRNA expression to more than three times the control value (P < 0.01). MMP-2 mRNA expression in control rats was threefold greater than that in the DHEA-induced group (P < 0.05). Expression of both latent and active forms of MMP-2 in controls was more than twice that in the DHEA-induced group (P < 0.05) as shown by Western blotting, and expression of the active form of MMP-2 was also twice as high in the controls as in the DHEA-treated group (P < 0.05) as shown by zymography. Our results suggest that depression of MMP-2 activity and increased LOX expression may be one of the causes of the cystogenesis of PCO.

Excessive androgen exposure in female-to-male transsexual persons of reproductive age induces hyperplasia of the ovarian cortex and stroma but not polycystic ovary morphology.

STUDY QUESTION Does administration of androgen to female-to-male transsexual persons (FTMs) of reproductive age induce polycystic ovary (PCO) morphology? SUMMARY ANSWER Administration of high-dose androgen to women causes pathognomonic changes to the ovarian cortex and stroma that resemble Stein-Leventhal syndrome but it does not induce PCO morphology. WHAT IS KNOWN ALREADY Androgen is thought to play a key role in follicular development and to be involved in the pathophysiology of polycystic ovary syndrome (PCOS). In several experimental models, animals given high-dose androgen show ovarian changes similar to those in women with PCOS. In previous human studies, the ovaries of FTMs who received androgen for long periods also exhibited PCO morphology. STUDY DESIGN, SIZE, DURATION We conducted a retrospective case-control study of women, all without PCOS, undergoing salpingo-oophorectomy. The case group consisted of 11 FTMs taking testosterone (duration range: 17 months to 14 years), while the control group consisted of 10 patients with gynaecologic malignancies who did not receive testosterone. PARTICIPANTS/MATERIALS, SETTING, METHODS Resected ovaries from both groups were compared histologically with respect to changes in the cortex and stroma, and the number of follicles at each maturation stage. MAIN RESULTS AND THE ROLE OF CHANCE Compared with controls, the FTM group had a thicker ovarian cortex (P = 0.0001), and more hyperplastic collagen (P = 0.001), ovarian stromal hyperplasia (P = 0.003) and stromal luteinization, i.e. luteinized stromal cells with a small dark central nucleus surrounded by clear cytoplasm (P = 0.004). Isolated clusters of such stromal luteinized cells were found only in the testosterone-treated ovaries of FTMs. The number of primordial follicles was similar in the two groups (P = 0.22). The numbers of early stage (primary, pre-antral and early antral) follicles, which are dependent on androgen, were also similar (P = 0.81), as were the numbers of antral follicles (P = 0.97). In contrast, significantly greater numbers of atretic follicles were seen in the FTM than that in the control group (P = 0.01). LIMITATIONS, REASON FOR CAUTION In addition to the low numbers in the study groups, the histological changes in FTMs were investigated after testosterone administration, therefore it is possible that some of the observed changes were already present, before androgen administration. WIDER IMPLICATION OF THE FINDINGS Our results are at variance with those of earlier studies and suggest that excessive androgen exposure in women of reproductive age may not be a factor in the pathogenesis of PCOS.

Distinctive features of female-to-male transsexualism and prevalence of gender identity disorder in Japan.

INTRODUCTION The prevalence of transsexualism is thought to differ among socio-geographic backgrounds, and little is known about its prevalence in Japan. Polycystic ovary syndrome (PCOS), which is known to be associated with insulin resistance and metabolic syndrome, is often seen in female-to-male (FTM) transsexual patients. Consequently, detection of PCOS is an important part of health care for these individuals. AIM The purpose of this study was to assess the prevalence of transsexuality in Japan, as well as the incidences of PCOS and insulin resistance among Japanese FTM transsexual patients. METHODS One hundred four male-to-female (MTF) and 238 FTM Japanese transsexual patients were studied. Medical histories, including histories of menstrual cycling and hormone treatment, were taken. To exclude other diseases, such as congenital adrenal hyperplasia and hormone-secreting tumors, thorough medical assessments, including transvaginal or transrectal ultrasonography and measurement of serum hormone levels and insulin resistance indexes, were performed. MAIN OUTCOME MEASURES The diagnosis of PCOS was based on the Rotterdam 2003 criteria. RESULTS Based on demographic statistics, the prevalences of MTF and FTM transsexuality are about 3.97 and 8.20 per 100,000 people, respectively, making the MTF-to-FTM ratio about 1:2. Of the FTM transsexual patients studied, 128 had not taken hormones before their initial assessment (untreated group); the remaining 50 self-administered androgen. Among the untreated group, 32.0% were diagnosed with PCOS, 30.1% were insulin-resistant, and 31.1% showed hypoadiponectinemia. CONCLUSIONS The sex ratio among Japanese transsexuals is different than among Caucasians. PCOS and insulin resistance are common findings in FTM transsexual patients at initial presentation.

Apoptosis and PCNA expression induced by prolactin in structural involution of the rat corpus luteum

There are two stages of luteal regression. The first stage is functional regression that is characterized by a decreased production of progesterone secretion; the second stage of structural involution is referred to as a structural luteolysis. In rodents, prolactin has a biphasic action on the corpus luteum. It is luteotrophic, but when exposed to functionally regressed corpora lutea it causes luteolysis. The objective of the present studies was to examine mechanisms of prolactin action in structural luteolysis, whether apoptosis is involved in this process, and to examine the possible association of cell proliferation signals as mediators of structural luteolysis. Prolactin-induced structural luteolysis was associated with apoptosis verified by terminal deoxynucleotidyl transferase (TdT)- mediated dUTP-biotin nick end labeling (TUNEL). Apoptotic cells made up about 3% of the cells 24 hours after the first injection of prolactin, a level that remained constant at all stages of structural luteolysis. Total ovarian weight and DNA content were decreased about 50% in 72 hours after induction of structural luteolysis by prolactin. The finding of about 3% of cells in apoptosis indicates apoptosis is a rapid process. Proliferating cell nuclear antigens (PCNA) of luteal cells were significantly decreased during functional luteal regression, but were conversely increased in structural luteolysis as shown by western blotting and immunohistochemistry. In general PCNA expression is reported to be decreased during structural involution, and there are no reports that have linked excess expression of PCNA with apoptosis and structural luteolysis. We speculate that an excessive increase in expression of PCNA which signals activation of cell proliferation creates a disorder in the signals involved with DNA synthesis. This disorder results in mitotic catastrophe and in the induction of apoptosis. Therefore the disorder of cell cycle signals in luteal cells are associated with prolactin induced apoptosis in structural luteolysis.

Effects of estradiol and an aromatase inhibitor on progesterone production in human cultured luteal cells

The human corpus luteum produces both estradiol and progesterone. It is well known that there are both autocrine and paracrine systems for the regulation of the corpus luteum and that estradiol regulates the progesterone production of the corpora lutea of some other species. To assess the direct effects of estrogen on human luteal function, we performed cell culture experiments. A low concentration of estradiol, almost equal to the amount of estradiol produced by human cultured luteal cells, directly stimulated progesterone production. 4-Cyclohexylaniline, an aromatase inhibitor, significantly reduced both progesterone production and estradiol production. Levels of estradiol higher than the levels that cultured human luteal cells themselves produced significantly reduced basal progesterone production and also significantly reduced human chorionic gonadotropin (hCG), forskolin and dibutyryl-cyclic AMP-stimulated progesterone production. According to these data, high doses of estradiol produced a luteolytic action which widely inhibited the steroidogenesis process. In conclusion, our results indicated that estradiol in part regulates progesterone production physiologically and blocks progesterone production in a pharmacological or pathological state in the human corpus luteum.

Remarkable features of ovarian morphology and reproductive hormones in insulin-resistant Zucker fatty (fa/fa) rats

BackgroundZucker fatty (fa/fa) rats are a well-understood model of obesity and hyperinsulinemia. It is now thought that obesity/hyperinsulinemia is an important cause of endocrinological abnormality, but to date there have been no reports on the changes in ovarian morphology or the ovarian androgen profile in rat models of obesity and insulin resistance.MethodsIn this study we investigated the effects of obesity and hyperinsulinemia on ovarian morphology and the hormone profile in insulin-resistant Zucker fatty rats (5, 8, 12 and 16 weeks of age, n = 6-7).ResultsOvaries from 5-week-old fatty rats had significantly greater total and atretic follicle numbers, and higher atretic-to-total follicle ratios than those from lean rats. Ovaries from 12- and 16-week-old fatty rats showed interstitial cell hyperplasia and numerous cysts with features of advanced follicular atresia. In addition, serum testosterone and androstenedione levels significantly declined in fatty rats from age 8 to 16 weeks, so that fatty rats showed significantly lower levels of serum testosterone (12 and 16 weeks) and androstenedione (all weeks) than lean rats. This may reflect a reduction of androgen synthesis during follicular atresia. Serum adiponectin levels were high in immature fatty rats, and although the levels declined significantly as they matured, it remained significantly higher in fatty rats than in lean rats. On the other hand, levels of ovarian adiponectin and its receptors were significantly lower in mature fatty rats than in lean mature rats or immature fatty rats.ConclusionsOur findings indicate that ovarian morphology and hormone profiles are significantly altered by the continuous insulin resistance in Zucker fatty rats. Simultaneously, abrupt reductions in serum and ovarian adiponectin also likely contribute to the infertility seen in fatty rats.

The effects of growth hormone on corpus luteum of superovulated rats.

In general, growth hormone acts as a factor promoting cell proliferation in the positive direction and suppresses apoptosis. No report has described growth hormone (GH)-induced structural luteolysis. The present studies showed that GH induced structural luteolysis in rats after the induction of functional luteolysis by treatment with bromocriptine, and that apoptotic cells were present among luteal cells during structural luteolysis as shown by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling. Zymography showed that the activity of matrix metalloproteinase (MMP)-2 increased during GH-induced structural luteolysis. The expression of c-myc protein of luteal cells was significantly decreased, but proliferating cell nuclear antigens (PCNA) were conversely increased during structural luteolysis, as shown by Western blot analysis. We propose that an excessive increase in PCNA and a marked decrease in c-myc protein of luteal cells lead to a disorder in the signals concerned with DNA synthesis, causing mitotic catastrophe and inducing apoptosis in luteal cells, and that structural luteolysis may be triggered. GH-induced apoptosis in structural luteolysis therefore highly depends on the cell cycle. There are thought to be two mechanisms of GH-induced structural luteolysis. One is apoptosis, and the other is destruction of extracellular matrix by MMP.

Activation of phospholipase D by prostaglandin F2α in rat luteal cells and effects of inhibitors of arachidonic acid metabolism

In rat luteal cells labeled with [3H]oleic acid, PGF2 alpha-stimulated phospholipase D (PLD) activation was investigated. The PLD activity was detected by measuring the accumulation of [3H]phosphatidylethanol (PtdEt) in the presence of ethanol. PGF2 alpha stimulated PtdEt accumulation at concentrations of more than 100 nM in the presence of ethanol. However, PtdEt accumulation did not change in the absence of ethanol. PGF2 alpha (1 microM) increased PtdEt accumulation after 1 min, and the accumulation reached a plateau by 2-3 min. These results indicate that PGF2 alpha activates PLD in rat luteal cells. U-73122, a phospholipase C (PLC) inhibitor, and staurosporine, a protein kinase C (PKC) inhibitor, did not inhibit PGF2 alpha-stimulated [3H]PtdEt accumulation. These results suggest that PGF2 alpha-induced PLD activation is different from PLC-PKC systems. We reported previously that PGF2 alpha stimulated the release of arachidonic acid. The effects of indomethacin, nordihydroguaiaretic acid (NDGA), and 5,8,11,14-eicosatetraynoic acid (ETYA), inhibitors of arachidonic acid metabolism, on PGF2 alpha-stimulated PtdEt accumulation were examined. Pretreatment with indomethacin enhanced PGF2 alpha-induced PtdEt accumulation. In contrast, pretreatment with NDGA and ETYA inhibited PGF2 alpha-induced PtdEt accumulation. It is suggested that PGF2 alpha-stimulated PLD activation is mediated via lipoxygenase products.

A Case of a Screlosing Stromal Ovarian Tumor That Expresses VEGF

A case of a sclerosing stromal tumor (SST) of the ovary is presented. One of the tumors characteristics was its high vascularity. On immunohistochemical staining, the vascular endothelial growth factor (VEGF) was positive for both cellular and edematous areas in the tumor. VEGF was thought to be a factor that affected the clinicopathological features of this tumor.

Assisted reproductive technique increases the risk of placental polyp.

Abstract The purpose of this study was to clarify the risk factors and outcomes of placental polyp. This retrospective study was conducted on 1645 patients delivered or aborted in Sapporo Medical University from 2007 through 2011. Transvaginal color Doppler ultrasonography, hysteroscopy, contrast-enhanced MRI or 3D-CT angiography were performed. There were 1532 deliveries and 113 abortions. Seventy-one (4.3%) were ART-conceived and the remaining 1574 (95.7%) were non-ART pregnancies. Fifteen (0.91%) cases were confirmed as having placental polyp. Nine cases of placental polyp were identified among the 1574 (0.57%) as non-ART-related pregnancies, and 6 were identified among the 71 (8.5%) as ART-related pregnancies. Thus, pregnancies achieved through ART showed 20x greater incidence of complicating placental polyp than pregnancies achieved through without ART (p = 9.02 × 10−6; odds ratio, 19.59; 95% confidence interval, 5.27–72.84, logistic regression analysis). Evaluation of blood flow within the polyp showed that in five of seven patients with low blood flow, the polyps spontaneously dropped off 79–115 days postpartum. Thus, ART-related pregnancies may be a risk factor of placental polyp, and spontaneous drop-off of the polyp is often observed in cases with low blood flow within the mass.