Improved FSH sensitisation and aromatase assay in human granulosa-lutein cells

Pulmonary arterial hypertension: Sex matters

Pulmonary arterial hypertension (PAH) is a complex disease of multifactorial origin. While registries have demonstrated that women are more susceptible to the disease, females with PAH have superior right ventricle (RV) function and a better prognosis than their male counterparts, a phenomenon referred to as the 'estrogen paradox'. Numerous pre-clinical studies have investigated the involvement of sex hormones in PAH pathobiology, often with conflicting results. However, recent advances suggest that abnormal estrogen synthesis, metabolism and signalling underpin the sexual dimorphism of this disease. Other sex hormones, such as progesterone, testosterone and dehydroepiandrosterone may also play a role. Several non-hormonal factor including sex chromosomes and epigenetics have also been implicated. Though the underlying pathophysiological mechanisms are complex, several compounds that modulate sex hormones levels and signalling are under investigation in PAH patients. Further elucidation of the estrogen paradox will set the stage for the identification of additional therapeutic targets for this disease.

Effect of adiponectin on estradiol and progesterone secretion from human luteinized granulosa cells in vitro

Ιnformation on the role of adiponectin in human ovarian steroidogenesis is limited. The present study aimed to investigate the effect of different doses of adiponectin on the secretion of estradiol and progesterone by human luteinized granulosa cells in culture. Granulosa cells, obtained from women undergoing in vitro fertilization (IVF) treatment, were pre-incubated for 24 h and then cultured for 48 h. Adiponectin was used in 3 doses, i.e., 5, 10, and 100 μg/ml alone and in combinations with FSH (10 and 100 ng/ml). Estradiol and progesterone were measured by radioimmunoassays in culture supernatants at 24 h and 48 h. Adiponectin after 48 h of culture stimulated the secretion of estradiol and, to a lesser extent, progesterone in a dose-dependent manner. FSH showed a variable effect on steroidogenesis. However, when the low dose FSH was combined with adiponectin, estradiol, and progesterone secretion were increased disproportionally to the dose of adiponectin. With the high dose FSH, the positive effect of adiponectin on FSH-induced estradiol secretion was less pronounced, while the effect on progesterone secretion was negligible. This study shows for the first time a stimulatory effect of adiponectin on the secretion of estradiol and progesterone by human luteinized granulosa cells in vitro. It is suggested that adiponectin plays a paracrine role in human ovarian steroidogenesis by sensitizing the granulosa cells to FSH.

The influence of deoxynivalenol and zearalenone on steroid hormone production by porcine ovarian granulosa cells in vitro

Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEA) are frequently occurring in feed of pigs together. The aim of this study was to evaluate the possible in vitro effects of DON and ZEA, alone or their combination on steroid secretion of porcine ovarian granulosa cells (GCs). A species-specific model with porcine ovarian GCs was used to study the potential endocrine disrupting effects of DON and ZEA alone and in co-exposure. Progesterone (P4) and estradiol (E2) were determined by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). The results of this study demonstrate that DON alone at the higher concentrations may act to stimulate P4 (at 1,000, 2,000, 3,000 and 5,000 ng mL^-1 but not 10 and 100 ng mL^-1) and E2 (at 2,000, 3,000 and 5,000 ng mL^-1 but not 10, 100 and 1000 ng mL^-1) secretion. The effects of ZEA on P4 and E2 secretion were not confirmed. DON in combination with the other fusariotoxin ZEA may impair steroidogenesis. Results aslo demonstrate different toxicological effects of fusariotoxins on follicle stimulating hormone-induced secretion of P4 and E2. All these results taken together suggest that fusariotoxin and their interactions can impact ovarian steroidogenesis, thereby demonstrating their potential reproductive effects in pigs.

Aging-related premature luteinization of granulosa cells is avoided by early oocyte retrieval

Why IVF pregnancy rates decline sharply after age 43 is unknown. In this study, we compared granulosa cell (GC) function in young oocyte donors (n=31, ages 21-29), middle-aged (n=64, ages 30-37) and older infertile patients (n=41, ages 43-47). Gene expressions related to gonadotropin activity, steroidogenesis, apoptosis and luteinization were examined by real-time PCR and western blot in GCs collected from follicular fluid. FSH receptor (FSHR), aromatase (CYP19A1) and 17β-hydroxysteroid dehydrogenase (HSD17B) expression were found down regulated with advancing age, while LH receptor (LHCGR), P450scc (CYP11A1) and progesterone receptor (PGR) were up regulated. Upon in vitro culture, GCs were found to exhibit lower proliferation and increased apoptosis with aging. While FSH supplementation stimulated GCs growth and prevented luteinization in vitro. These observations demonstrate age-related functional declines in GCs, consistent with premature luteinization. To avoid premature luteinization in women above age 43, we advanced oocyte retrieval by administering human chorionic gonadotropin at maximal leading follicle size of 16  mm (routine 19-21  mm). Compared to normal cycles in women of similar age, earlier retrieved patients demonstrated only a marginal increase in oocyte prematurity, yet exhibited improved embryo numbers as well as quality and respectable clinical pregnancy rates. Premature follicular luteinization appears to contribute to rapidly declining IVF pregnancy chances after age 43, and can be avoided by earlier oocyte retrieval.

Effect of Anti-Müllerian hormone (AMH) and bone morphogenetic protein 15 (BMP-15) on steroidogenesis in primary-cultured human luteinizing granulosa cells through Smad5 signalling

PURPOSE

To determine if there is any effect of AMH and BMP-15 on estradiol and progesterone production from primary-cultured human luteinizing granulosa cells, to delineate what is the effect of FSH on their actions and which are the possible mechanisms involved.

METHODS

Luteinizing granulosa cells (GCs), obtained from follicular fluid of 30 women undergoing in vitro fertilization, were cultured, after a short 24-h preincubation period, in serum-free medium for 24 or/and 48 h in the presence/absence of various concentrations of AMH, BMP-15 and FSH alone or in combinations. Estradiol and progesterone production, SMAD5 phosphorylation and StAR expression were studied in parallel. Steroids were measured in culture-supernatant using enzyme-immunoassays, while Smad5-signaling pathway activation and StAR protein expression were assessed immunocytochemically.

RESULT(S)

We found that the treatment of AMH in GCs for 24/48 h attenuated FSH-induced estradiol production (p < 0.001), had no effect on basal estradiol levels, decreased basal progesterone production (p < 0.001) and FSH-induced StAR expression (p < 0.001). On the other hand, BMP-15 decreased basal estradiol levels (p < 0.001) and attenuated FSH-induced estradiol production (p < 0.001). Furthermore, BMP-15 reduced progesterone basal secretion (p < 0.001), an effect that was partially reversed by FSH (p < 0.01), probably via increasing StAR expression (p < 0.001). FSH-induced StAR expression was also attenuated by BMP-15 (p < 0.001). FSH, AMH and BMP-15 activated Smad-signaling pathway, as confirmed by the increase of phospo-Smad5 protein levels (p < 0.001 compared to control).

CONCLUSION(S)

AMH and BMP-15 by interacting with FSH affect the production of estradiol and progesterone from cultured luteinizing-granulosa cells possibly via Smad5-protein phosphorylation.

Effect of incubation with different concentrations and durations of FSH for in-vitro maturation of murine oocytes

The purpose of the study was to evaluate whether a lower concentration of FSH or 2-h incubation with FSH would improve the outcome of in-vitro maturation of oocytes. The immature oocytes were obtained from FVB mice, and were allocated to four groups and incubated in the maturation media for 24 h. The maturation media were supplemented with 10 mIU/ml FSH for 24 h (group 1), 10 mIU/ml FSH for 2 h (group 2), 75 mIU/ml FSH for 24 h (group 3) or 75 mIU/ml FSH for 2 h (group 4). In each group, half of the in-vitro-matured oocytes were fertilized and cultured to blastocysts and the remaining matured oocytes were analysed for growth differentiation factor (GDF)-9 and bone morphogenetic protein (BMP)-15 mRNA to assess the oocyte quality. The maturation rates and oocyte BMP-15 mRNA concentrations were similar among the four groups. The GDF-9 mRNA concentrations were similar in group 2 and group 4. The fertilization and blastocyst rates were higher in groups 2 and 4 than in groups 1 and 3. It is concluded that 2-h incubation with FSH is better than 24-h incubation in terms of the fertilization rate and blastocyst development.

Modulating effect of leptin on basal and follicle stimulating hormone stimulated steroidogenesis in cultured human lutein granulosa cells

BACKGROUND

In vitro data have shown conflicting results in terms of the effect of leptin on granulosa cells steroidogenesis.

AIM

The aim of the present study was to investigate the effect of low and high doses of leptin on basal and FSH-induced steroids secretion by human luteinized granulosa cells in culture.

MATERIALS AND METHODS

Granulosa cells were obtained from normal women undergoing in vitro fertilization (IVF) treatment and were cultured in serum-free conditions for 72 h. A one-way analysis of variance design was set to study the effect of leptin on basal and FSH-induced steroidogenesis.

RESULTS

Leptin affected basal estradiol and progesterone secretion in a dose-related manner. In particular, leptin at low concentrations stimulated the secretion of estradiol (1 and 10 ng/ml) and progesterone (10 ng/ml), while at a high concentration (100 ng/ml) it suppressed the secretion of both steroids. A dose-related effect of leptin on FSH-induced steroidogenesis was not evident, since only the suppressive effect of the high concentration of leptin (100 ng/ml) reached statistical significance for both steroids.

CONCLUSIONS

These results demonstrate that leptin affects the secretion of steroids in luteinized granulosa cells in a dose-dependent manner. Although a physiological role for leptin is possible, it is suggested that this protein is a mediator of negative rather than positive influential interactions on ovarian function that may compromise fertility.

Valproate inhibits the conversion of testosterone to estradiol and acts as an apoptotic agent in growing porcine ovarian follicular cells

PURPOSE

Long-term valproate (VPA) treatment has been associated with hyperandrogenism and polycystic ovaries in women with epilepsy. The exact mechanisms of action of the drug on sex steroid hormone function are still unsettled. The aim of the present study was to investigate the action of VPA on basal and gonadotropin-stimulated steroid secretion in porcine ovarian follicular cells and to measure the conversion of testosterone to estradiol. Second, the action of VPA on proliferation and apoptosis of follicular cells was investigated.

METHODS

Small and medium follicles were obtained from pig ovaries on days 8-10 and 14-16 of the estrus cycle. Both follicular compartments, theca and granulosa cells, were cultured as a coculture resembling follicles in vivo. VPA in concentrations of 100 and 250 micrg/ml was added to the control or gonadotropin-stimulated cultures.

RESULTS

VPA caused a significant increase in basal and luteinizing hormone (LH)-stimulated testosterone secretion from small follicles, whereas in medium follicles, an increased basal but decreased LH-stimulated testosterone secretion was found. VPA caused decreased basal and follicle-stimulating hormone (FSH)-stimulated estradiol secretion by small follicles, whereas only the higher concentration decreased estradiol secretion in medium follicles. The conversion of testosterone to estradiol by small follicles was decreased under the influence of VPA in testosterone-alone and in testosterone-plus-FSH-stimulated cultures, whereas this was seen at only the higher VPA concentration in medium follicles. VPA had no effect on cell proliferation and viability, whereas in a dose-dependent manner, VPA increased caspase-3 activity.

CONCLUSIONS

VPA affected steroidogenesis in both unstimulated and gonadotropin-stimulated porcine ovarian follicular cells and inhibited the conversion of testosterone to estradiol. In addition, VPA may act as an apoptotic agent in both small and medium-sized follicles.