Changes in peripheral serum levels of total activin A during the human menstrual cycle and pregnancy

Integrated trajectories of the maternal metabolome, proteome, and immunome predict labor onset

Estimating the time of delivery is of high clinical importance because pre- and postterm deviations are associated with complications for the mother and her offspring. However, current estimations are inaccurate. As pregnancy progresses toward labor, major transitions occur in fetomaternal immune, metabolic, and endocrine systems that culminate in birth. The comprehensive characterization of maternal biology that precedes labor is key to understanding these physiological transitions and identifying predictive biomarkers of delivery. Here, a longitudinal study was conducted in 63 women who went into labor spontaneously. More than 7000 plasma analytes and peripheral immune cell responses were analyzed using untargeted mass spectrometry, aptamer-based proteomic technology, and single-cell mass cytometry in serial blood samples collected during the last 100 days of pregnancy. The high-dimensional dataset was integrated into a multiomic model that predicted the time to spontaneous labor [R = 0.85, 95% confidence interval (CI) [0.79 to 0.89], P = 1.2 × 10^-40, N = 53, training set; R = 0.81, 95% CI [0.61 to 0.91], P = 3.9 × 10^-7, N = 10, independent test set]. Coordinated alterations in maternal metabolome, proteome, and immunome marked a molecular shift from pregnancy maintenance to prelabor biology 2 to 4 weeks before delivery. A surge in steroid hormone metabolites and interleukin-1 receptor type 4 that preceded labor coincided with a switch from immune activation to regulation of inflammatory responses. Our study lays the groundwork for developing blood-based methods for predicting the day of labor, anchored in mechanisms shared in preterm and term pregnancies.

Terminal differentiation of human granulosa cells as luteinization is reversed by activin-A through silencing of Jnk pathway

Molecular mechanisms underlying luteinization (terminal differentiation of granulosa and theca cells after ovulation) and luteolysis (demise of corpus luteum) are poorly understood in human ovary. Here we report that activin-A, after binding to its cognate receptors induces a functional luteolytic state and reverses luteinization phenotype by downregulating the expression of the steroidogenic enzymes, LH receptor and VEGF and reducing estradiol (E2) progesterone (P4) production and upregulating FSH receptor and cyclin D1 expression in human primary luteinized granulosa cells. Further, this action of activin-A involves downregulation of JNK signaling pathway and is opposite to that of human chorionic gonadotropin (hCG), which acts as a luteotropic hormone and improves luteal function through the activation of JNK pathway in the same cell type. Reversal of luteinization phenotype in luteal granulosa cells by activin-A potentially makes this hormone an attractive candidate for use under certain clinical situations, where induction of luteolysis and rapid reduction of endogenous sex steroid levels are beneficial such as ovarian hyperstimulation syndrome (OHSS), in which the ovaries hyper-respond to gonadotropin stimulation by producing too many growing follicles along with development of ascites, pleural effusion, and hemo-concentrations as a result of increased vascular permeability and leakage of intravascular volume into third spaces. Our work unveils a previously undefined role for activin-A and JNK signaling pathway in human corpus luteum biology, that might have a direct clinical impact in assisted reproductive technologies.

Changes in pregnancy-related serum biomarkers early in gestation are associated with later development of preeclampsia

Background

Placental protein expression plays a crucial role during pregnancy. We hypothesized that: (1) circulating levels of pregnancy-associated, placenta-related proteins throughout gestation reflect the temporal progression of the uncomplicated, full-term pregnancy, and can effectively estimate gestational ages (GAs); and (2) preeclampsia (PE) is associated with disruptions in these protein levels early in gestation; and can identify impending PE. We also compared gestational profiles of proteins in the human and mouse, using pregnant heme oxygenase-1 (HO-1) heterozygote (Het) mice, a mouse model reflecting PE-like symptoms.

Methods

Serum levels of placenta-related proteins–leptin (LEP), chorionic somatomammotropin hormone like 1 (CSHL1), elabela (ELA), activin A, soluble fms-like tyrosine kinase 1 (sFlt-1), and placental growth factor (PlGF)–were quantified by ELISA in blood serially collected throughout human pregnancies (20 normal subjects with 66 samples, and 20 subjects who developed PE with 61 samples). Multivariate analysis was performed to estimate the GA in normal pregnancy. Mean-squared errors of GA estimations were used to identify impending PE. The human protein profiles were then compared with those in the pregnant HO-1 Het mice.

Results

An elastic net-based gestational dating model was developed (R² = 0.76) and validated (R² = 0.61) using serum levels of the 6 proteins measured at various GAs from women with normal uncomplicated pregnancies. In women who developed PE, the model was not (R² = -0.17) associated with GA. Deviations from the model estimations were observed in women who developed PE (P = 0.01). The model developed with 5 proteins (ELA excluded) performed similarly from sera from normal human (R² = 0.68) and WT mouse (R² = 0.85) pregnancies. Disruptions of this model were observed in both human PE-associated (R² = 0.27) and mouse HO-1 Het (R² = 0.30) pregnancies. LEP outperformed sFlt-1 and PlGF in differentiating impending PE at early human and late mouse GAs.

Conclusions

Serum placenta-related protein profiles are temporally regulated throughout normal pregnancies and significantly disrupted in women who develop PE. LEP changes earlier than the well-established biomarkers (sFlt-1 and PlGF). There may be evidence of a causative action of HO-1 deficiency in LEP upregulation in a PE-like murine model.

Neuroendocrine, autocrine, and paracrine control of follicle-stimulating hormone secretion

Follicle-stimulating hormone (FSH) is a glycoprotein hormone produced by gonadotropes in the anterior pituitary that plays a central role in controlling ovarian folliculogenesis and steroidogenesis in females. Moreover, recent studies strongly suggest that FSH exerts extragonadal actions, particularly regulating bone mass and adiposity. Despite its crucial role, the mechanisms regulating FSH secretion are not completely understood. It is evident that hypothalamic, ovarian, and pituitary factors are involved in the neuroendocrine, paracrine, and autocrine regulation of FSH production. Large animal models, such as the female sheep, represent valuable research models to investigate specific aspects of FSH secretory processes. This review: (i) summarizes the role of FSH controlling reproduction and other biological processes; (ii) discusses the hypothalamic, gonadal, and pituitary regulation of FSH secretion; (iii) considers the biological relevance of the different FSH isoforms; and (iv) summarizes the distinct patterns of FSH secretion under different physiological conditions.

Decrease in preovulatory serum estradiol is a valuable marker for predicting premature ovulation in natural/unstimulated in vitro fertilization cycle

Background

Premature ovulation occurs at a high rate in natural-cycle in vitro fertilization (IVF), and cycle cancellation further hampers the overall efficiency of the procedure. While lower levels of estradiol (E2) are observed in preovulatory follicles, it is unclear whether declines in E2 can be used as an effective marker of premature ovulation.

Methods

This retrospective analysis includes 801 natural/unstimulated IVF/ICSI cycles undergoing scheduled ovum pick-up (OPU) and 153 natural/unstimulated IVF/ICSI cycles undergoing emergency OPU at a university IVF center from May 2014 to February 2017.

Results

Among the 801 IVF/ICSI cycles undergoing scheduled OPU, preovulatory E2 levels increased by more than 10% in 403 (50.31%) cycles of the sample (Group A), while 192 (23.97%) cycles experienced a plateau (increased or decreased by 10%; Group B), and 206 (25.72%) cycles decreased by more than 10% (Group C). Group C had more patients who experienced premature LH surges, premature ovulation, as well as the fewest oocytes retrieved, frozen embryos, and top-quality embryos. A multivariate logistic regression analysis indicated that premature ovulation was associated with preovulatory E2/−1E2 ratio and premature LH surge. Moreover, preovulatory E2/−1E2 ratio served as a valuable marker for differentiating premature ovulation, with an AUC (area under the receiver operating curve) of 0.708 and 0.772 in cycles with premature LH surges and cycles without premature LH surges, respectively. Emergency OPU resulted in a significantly decreased rate of premature ovulation and increased number of frozen embryos.

Conclusion

Decreases in preovulatory serum E2 was a valuable marker for premature ovulation in natural/unstimulated IVF cycle. Emergency OPU based on the preovulatory E2/−1E2 ratio decreased the rate of premature ovulation in cycles that experienced E2 decreases.

Electronic supplementary material

The online version of this article (10.1186/s13048-018-0469-x) contains supplementary material, which is available to authorized users.

Regulation of the activins-follistatins-inhibins axis by energy status: Impact on reproductive function

BACKGROUND

We have previously demonstrated that the adipose tissue derived hormone leptin controls reproductive function by regulating the hypothalamic-pituitary-gonadal axis in response to energy deficiency. Here, we evaluate the activins-follistatins-inhibins (AFI) axis during acute (short-term fasting in healthy people) and chronic energy deficiency (women with hypothalamic amenorrhea due to strenuous exercise [HA]) and investigate their relation to leptin and reproductive function in healthy subjects and subjects with HA.

METHODS

The AFI axis was investigated in: a) A double-blinded study in healthy subjects having three randomly assigned admissions, each time for four days: in the isocaloric fed state, complete fasting with placebo treatment, complete fasting with leptin replacement, b) A case-control study comparing women with HA vs healthy controls, c) An open-label interventional study investigating leptin treatment in women with HA over a period of up to three months, d) A randomized interventional trial investigating leptin treatment vs placebo in women with HA for nine months.

RESULTS

The circulating levels of activin A, activin B, follistatin and follistatin-like 3 change robustly in response to acute and chronic energy deficiency. Leptin replacement in acute energy deprivation does not affect the levels of these hormones suggesting an independent regulation by these two hormonal pathways. In chronic energy deficiency, leptin replacement restores only activin B levels, which are in turn associated with an increase in the number of dominant follicles.

CONCLUSIONS

We demonstrate for the first time that the AFI axis is affected both by acute and chronic energy deficiency. Partial restoration of a component of the axis, i.e. activin B only, through leptin replacement is associated with improved reproductive function in women with HA.

Oral contraceptives cause evolutionarily novel increases in hormone exposure: A risk factor for breast cancer

Background and objectives: In the evolutionary past, women spent most of their reproductive lives either pregnant or in lactational amenorrhea, and rarely menstruated. The current pattern of frequent menses, and the associated increase in endogenous hormonal exposure, has been implicated in the current breast cancer epidemic. It is not known, however, whether oral contraceptives further increase, or actually decrease, hormonal exposure over one menstrual cycle. Here, we examined variation in hormonal exposure across seven oral contraceptive (OC) formulations, and produced the first quantitative comparison of exogenous versus endogenous hormone exposure. Methodology: Data from 12 studies of serum estradiol (E2) and progesterone (P4) were aggregated to create a composite graph of endogenous hormone levels over one menstrual cycle in European or American women (age 19-40 years). Pharmacokinetic package insert data, also from Western women, were used to calculate exposures for hormones in seven different OC formulations. Endogenous and exogenous hormone levels were compared after adjusting for the relative binding affinity (RBA) of progestin to the progesterone receptor and ethinyl estradiol (EE) to the estrogen receptor. Results: After adjusting for RBA, median ethinyl estradiol exposure across 28 days in the OCs was 11.4 nmol/l, similar to median E2 exposure. One formulation, however, was 40% higher in ethinyl estradiol exposure relative to median endogenous estradiol. Median exposure from progestins in OCs (1496 nmol/l) was 4-fold higher than the median endogenous exposure from P4 (364 nmol/l). Exposure from OC progestins ranged from one sixtieth to 8-fold median endogenous P4 over 28 days. Conclusions and implications: Given that breast cancer risk increases with hormonal exposure, our finding that four widely prescribed formulations more than quadruple progestin exposure relative to endogenous progesterone exposure is cause for concern. As not all formulations produce the same exposures, these findings are pertinent to contraceptive choice. We also identify critical gaps in the provision of relevant data on pharmacokinetics and carcinogenicity by drug manufacturers.

Change in the Gastro-Intestinal Tract by Overexpressed Activin Beta A

Originally, activins were identified as stimulators of FSH release in reproduction. Other activities, including secondary axis formation in development, have since been revealed. Here, we investigated the influence of activin βA on the body, including the gastro-intestinal (GI) tract. Initially, the activin βA protein was detected in the serum proportional to the amount of pCMV-rAct plasmid injected. The induced level of activin βA in muscle was higher in female than male mice. Subsequent results revealed that stomach and intestine were severely damaged in pCMV-rAct-injected mice. At the cellular level, loss of parietal cells was observed, resulting in increased pH within the stomach. This phenomenon was more severe in male than female mice. Consistent with damage of the stomach and intestine, activin βA often led to necrosis in the tip of the tail or foot, and loss of body weight was observed in pCMV-rAct-injected male but not female mice. Finally, in pCMV-rAct-injected mice, circulating activin βA led to death at supraphysiological doses, and this was dependent on the strain of mice used. Taken together, these results indicate that activin βA has an important role outside of reproduction and development, specifically in digestion. These data also indicate that activin βA must be controlled within a narrow range because of latent lethal activity. In addition, our approach can be used effectively for functional analysis of secreted proteins.

Engineering the ovarian cycle using in vitro follicle culture

STUDY QUESTION

Can cultured follicles model the ovarian cycle, including follicular- and luteal-phase hormone synthesis patterns and ovulation?

SUMMARY ANSWER

Under gonadotrophin stimulation, murine follicles grown in an encapsulated three-dimensional system ovulate in vitro and murine and human follicle hormone synthesis mimics follicular and luteal phases expected in vivo.

WHAT IS KNOWN ALREADY

Studies of the human ovary and follicle function are limited by the availability of human tissue and lack of in vitro models. We developed an encapsulated in vitro follicle growth (eIVFG) culture system, which preserves 3D follicular structure. Thus far, the alginate system has supported the culture of follicles from mice, dog, rhesus macaque, baboon and human. These studies have shown that cultured follicles synthesize steroid hormones similar to those observed during the follicular phase in vivo.

STUDY DESIGN, SIZE, DURATION

Cultured murine follicles were treated with human chorionic gonadotrophin (hCG) and epidermal growth factor (EGF) and either assayed for luteinization or removed from alginate beads and assayed for ovulation. Human follicles were also cultured, treated with follicle-stimulating hormone (FSH), hCG and EGF to mimic gonadotrophin changes throughout the ovarian cycle, and culture medium was assayed for hormone production.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Murine and human follicles were cultured in alginate hydrogel and hormone production [17β-estradiol, progesterone, inhibin A, inhibin B, activin A and anti-Müllerian hormone (AMH)] was quantified in medium by enzyme-linked immuno assay (ELISA). Human ovarian tissue was acquired from females between 6 and 34 years of age with a cancer diagnosis. These participants were undergoing ovarian tissue cryopreservation at National Physicians Cooperative sites as part of the Oncofertility Consortium.

MAIN RESULTS AND THE ROLE OF CHANCE

When grown in this system, 96% of mouse follicles ovulated in response to hCG and released meiotically competent eggs. Ovulated follicles recapitulated transcriptional, morphologic and hormone synthesis patterns post-luteinizing hormone (LH/hCG). In addition to rodent follicles, individual human follicles secreted steroid and peptide hormones that mimicked the patterns of serum hormones observed during the menstrual cycle.

LIMITATIONS, REASONS FOR CAUTION

This was a descriptive study of an in vitro model of ovulation and the ovarian hormone cycle. The ovulation studies were limited to murine tissue and further studies are needed to optimize conditions using other species.

WIDER IMPLICATIONS OF THE FINDINGS

The eIVFG system reliably phenocopies the in vivo ovarian cycle and provides a new tool to study human follicle biology and the influence of cycling female hormones on other tissue systems in vitro.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by NIH U54 HD041857, NIH U54 HD076188, NIH UH2 E5022920, NIH UH3 TR001207 and F30 AG040916 (R.M.S.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

In-vitro study of the effect of anti-hypertensive drugs on placental hormones and angiogenic proteins synthesis in pre-eclampsia

INTRODUCTION

Antihypertensive drugs lower the maternal blood pressure in pre-eclampsia (PE) by direct or central vasodilatory mechanisms but little is known about the direct effects of these drugs on placental functions.

OBJECTIVE

The aim of our study is to evaluate the effect of labetolol, hydralazine, α-methyldopa and pravastatin on the synthesis of placental hormonal and angiogenic proteins know to be altered in PE.

DESIGN

Placental villous explants from late onset PE (n = 3) and normotensive controls (n = 6) were cultured for 3 days at 10 and 20% oxygen (O2) with variable doses anti-hypertensive drugs. The levels of activin A, inhibin A, human Chorionic Gonadotrophin (hCG), soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng) were measured in explant culture media on day 1, 2 and 3 using standard immunoassays. Data at day 1 and day 3 were compared.

RESULTS

Spontaneous secretion of sEndoglin and sFlt-1 were higher (p < 0.05) in villous explants from PE pregnancies compared to controls. There was a significant time dependent decrease in the secretion of sFlt-1 and sEndoglin in PE cases, which was seen only for sFlt-1 in controls. In both PE cases and controls the placental protein secretions were not affected by varying doses of anti-hypertensive drugs or the different O2 concentration cultures, except for Activin, A which was significantly (p < 0.05) higher in controls at 10% O2.

INTERPRETATION

Our findings suggest that the changes previously observed in maternal serum hormones and angiogenic proteins level after anti-hypertensive treatment in PE could be due to a systemic effect of the drugs on maternal blood pressure and circulation rather than a direct effect of these drugs on placental biosynthesis and/or secretion.

Stress signaling from human mammary epithelial cells contributes to phenotypes of mammographic density

Telomere malfunction and other types of DNA damage induce an activin A-dependent stress response in mortal nontumorigenic human mammary epithelial cells that subsequently induces desmoplastic-like phenotypes in neighboring fibroblasts. Some characteristics of this fibroblast/stromal response, such as reduced adipocytes and increased extracellular matrix content, are observed not only in tumor tissues but also in disease-free breast tissues at high risk for developing cancer, especially high mammographic density tissues. We found that these phenotypes are induced by repression of the fatty acid translocase CD36, which is seen in desmoplastic and disease-free high mammographic density tissues. In this study, we show that epithelial cells from high mammographic density tissues have more DNA damage signaling, shorter telomeres, increased activin A secretion and an altered DNA damage response compared with epithelial cells from low mammographic density tissues. Strikingly, both telomere malfunction and activin A expression in epithelial cells can repress CD36 expression in adjacent fibroblasts. These results provide new insights into how high mammographic density arises and why it is associated with breast cancer risk, with implications for the definition of novel invention targets (e.g., activin A and CD36) to prevent breast cancer.

Gram-negative bacterial lipopolysaccharide stimulates activin a secretion from human amniotic epithelial cells

Activin A is involved in inflammation. The present study was performed to clarify if lipopolysaccharide, a component of Gram-negative bacteria, stimulates activin A secretion from human amniotic epithelial cells and to determine if activin A plays a role in amnionitis. Fetal membranes were obtained during elective cesarean sections performed in full-term pregnancies of patients without systemic disease, signs of premature delivery, or fetal complications. Amniotic epithelial cells were isolated by trypsinization. The activin A concentrations in the culture media were measured by enzyme-linked immunosorbent assay, and cell proliferation was assessed by 5-bromo-2'-deoxyuridine incorporation. Amniotic epithelial cells secreted activin A in a cell density-dependent manner, and lipopolysaccharide (10  μ g/mL) enhanced the secretion at each cell density. Lipopolysaccharide (10-50  μ g/mL) also stimulated activin A secretion in a dose-dependent manner. Contrary to the effect of activin A secretion, lipopolysaccharide inhibited cell proliferation in amniotic epithelial cells. The present study suggests that lipopolysaccharide stimulation of activin A secretion may be a mechanism in the pathogenesis of amnionitis.

Maternal circulating levels of activin A, inhibin A, sFlt-1 and endoglin at parturition in normal pregnancy and pre-eclampsia

Background

Maternal circulating levels of anti-angiogenic factors such as soluble fms-like tyrosine kinase-1 (sFlt-1), endoglin (sEng) and placental proteins like activin A and inhibin A are increased before the onset of pre-eclampsia. There is evidence for oxidative stress in pre eclampsia. Recently it was shown that placental oxygen concentration is related to sFlt-1 and inhibin A. In addition it is reported that oxidative stress markers are increased in placental tissue delivered after labour. Therefore, the objective of this study is to investigate if these proteins are altered in maternal circulation of labouring pre-eclampsia and normal pregnancies.

Methodology

To assess the effects of labour, samples were taken from 10 normal pregnant (NP) and 10 pre-eclamptic (PE) women pre-labour, full dilation, placental delivery and 24 h. To assess the effects of placental delivery, plasma samples were taken from 10NP and 10PE women undergoing elective Caesarean section, pre-delivery, placental delivery and 10 min, 60 min and 24 h post delivery. SFlt-1 and sEng and activin A and inhibin A were measured using commercial and in house ELISA's respectively.

Results

The levels of sFlt-1 and sEng were significantly higher in PE compared to NP women in both groups. In labour, sFlt-1 levels increased significantly at full dilatation in PE women, before declining by 24 hr. However there was no significant rise in sEng levels in labour. Activin A and inhibin A levels declined rapidly with placental delivery in NP and PE pregnancies. There was a significant rise in activin A levels during labour in PE compared to pre labour, but inhibin levels did not increase.

Conclusion

Labour in pre-eclamptic women increases the levels of sFlt-1 and activin A. This pilot data suggests that increase in the maternal levels of these factors in labour could predict and/or contribute to the maternal syndrome postpartum.

Changes in the reproductive function and developmental phenotypes in mice following intramuscular injection of an activin betaA-expressing plasmid

BACKGROUND

The TGF-beta family protein activin has numerous reported activities with some uncertainty in the reproductive axis and development. The precise roles of activin in in vivo system were investigated using a transient gain of function model.

METHODS

To this end, an expression plasmid, pCMV-rAct, with the activin betaA cDNA fused to the cytomegalovirus promoter, was introduced into muscle of the female adult mice by direct injection.

RESULTS

Activin betaA mRNA was detected in the muscle by RT-PCR and subsequent Southern blot analysis. Activin betaA was also detected, and western blot analysis revealed a relatively high level of serum activin with correspondingly increased FSH. In the pCMV-rAct-injected female mice, estrus stage within the estrous cycle was extended. Moreover, increased numbers of corpora lutea and a thickened granulosa cell layer with a small antrum in tertiary follicles within the ovary were observed. When injected female mice were mated with males of proven fertility, a subset of embryos died in utero, and most of those that survived exhibited increased body weight.

CONCLUSION

Taken together, our data reveal that activin betaA can directly influence the estrous cycle, an integral part of the reproduction in female mice and activin betaA can also influence the embryo development as an endocrine fashion.

Relationships between TGFbeta proteins and oxygen concentrations inside the first trimester human gestational sac

In early pregnancy, the O(2) gradient between the maternal circulation and the gestational sac tissues modulates trophoblast biological functions. The aim was to evaluate if placental partial pressure of oxygen (PaO(2)) modulates in vivo synthesis of specific placental proteins inside the first trimester gestational sac. Matched samples of peripheral venous blood, blood from the placental bed (PB), coelomic fluid (CF) and placental tissue were obtained in 37 normal pregnancies at 6-12 weeks gestation. PaO(2) was measured in PB and CF using an IRMA blood gas monitor. Inhibin A, activin A, sEng, PlGF, sFlt-1 and free VEGF concentrations were measured in all samples. HSP 70 was measured in placental extracts. ANOVA showed approximately 60% increase in PB PaO(2) (P = 0.02) between after 10 weeks gestation. Unpaired Student's T-test between two groups (6-9 weeks vs 9-12 weeks) shows a significant increase in MS Activin A (P = 0.001), CF activin A (P<0.001), MS P1GF (P = 0.001), CF PlGF (P<0.001), MS sFLT-1 (P = 0.03), CF sFLT-1 (P = 0.01), HSP 70 in placental extracts (P = 0.04) and a significant decrease in PB inhibin A levels (P<0.001) and PB sFLT-1 (P = 0.02) . Multiple correlation analysis showed a significant negative correlation between PB inhibin A levels and gestation (r = -0.45, P<0.05) and PB PaO(2) (r = -0.5, P = 0.008) and also between sFLT-1 and PB PaO(2) (P = 0.03). There was a positive correlation (P<0.01) between PlGF, sEng and VEGF levels in the placental extracts. Our results indicate a direct relationship in the early intrauterine PaO(2) in vivo and inhibin A and sFLT-1 concentrations confirming our hypothesis that specific placental proteins are regulated by intrauterine O(2) tension.

Activin-A in myometrium: characterization of the actions on myometrial cells

Activin is a pleiotropic growth factor with a broad pattern of tissue distribution that includes reproductive tissues. Although direct actions of activin have been described in gonadal and uterine tissues, actions in the myometrium have not been defined. In this study we have characterized the responsiveness of uterine tissue and myometrial cell lines to activin-A. Uterine tissue and two myometrial cell lines, PHM1 (pregnant human myometrial 1) and hTERT HM (telomerase reverse transcriptase-infected human myometrial) respond to activin-A as measured by phosphorylation of Smad-2. Those cell lines express a full complement of activin receptors, as well as activin beta(A) subunit and follistatin. Activin inhibited proliferation of PHM1 and human telomerase reverse transcriptase-infected human myometrial cell line cells, with more extensive growth inhibition observed in PHM1s. In PHM1s, activin-A decreased oxytocin receptor and HoxA-10 mRNA expression but did not alter total progesterone receptor, cyclooxygenase-2 (Cox-2), and connexin 43 mRNA expression levels. Furthermore, treatment of PHM1 myometrial cells with activin-A attenuated oxytocin and thromboxaneA2 induced intracellular Ca(2+) accumulation. In conclusion, myometrial cells are activin sensitive, and activin-A can regulate myometrial cell functions.

Predictors of ovarian reserve in young women with breast cancer

Ovarian reserve can be diminished following treatment for breast cancer. This study evaluated biochemical and biophysical parameters of ovarian reserve in these patients. Biochemical and biophysical tests of ovarian reserve were performed simultaneously in young (age 22–42 years), regularly menstruating women with breast cancer (n=22) and age-matched controls (n=24). All tests were performed before (baseline) and after transient ovarian stimulation in the early follicular phase. Patients were recruited both before and after completion of chemotherapy, with some patients being followed up prospectively. Serum samples were analysed for follicle-stimulating hormone (FSH), luteinising hormone (LH), oestradiol (E₂), inhibins A and B, and antimullerian hormone (AMH). Biophysical (ultrasound) tests included ovarian volume, antral follicle count (AFC), ovarian stromal blood flow and uterine dimensions. Significant differences were revealed (when compared with the controls) for basal FSH (11.32±1.48 vs 6.62±0.42 mIU ml⁻¹, P<0.001), basal AMH (0.95±0.34 vs 7.89±1.62 ng ml⁻¹, P<0.001) and basal inhibin B (19.24±4.56 vs 83.61±13.45 pg ml⁻¹, P<0.001). Following transient ovarian stimulation, there were significant differences in the increment change (Δ) for inhibin B (3.02±2.3 vs 96.82±16.38 pg ml⁻¹, P<0.001) and E₂ (107.8±23.95 vs 283.2±40.34 pg ml⁻¹, P<0.01). AFC was the only biophysical parameter that was significantly different between patients and the controls (7.80±0.85 vs 16.77±1.11, P<0.001). Basal and stimulated biochemical (serum AMH, FSH, inhibin B and E₂) and biophysical (AFC) tests may be potential markers of ovarian reserve in young women with breast cancer.

Differential effects of aging on activin A and its binding protein, follistatin, across the menopause transition

To assess the involvement of ovarian-derived regulatory proteins in FSH modulation, we compared FSH, inhibin A, inhibin B, activin A, and follistatin (FS) in 79 women from the following five groups: young cycling, older cycling, perimenopause (PERI), spontaneous menopause (PM), and surgical menopause receiving estrogen (OVX+ET). Although inhibin B varied as expected by ovarian function, no group differences were observed in activin A, barring a tendency for an increase in PERI, while FS 288 was lower in the PERI, PM, and OVX+ET groups and negatively correlated with advancing age.

Serum inhibin B correlates with successful ovulation in infertile women

PURPOSE

To investigate whether inhibin B and activin A serum and follicular fluid levels in infertile women undergoing induction of superovulation correlate with successful ovulation.

METHODS

Infertile women (n = 16) (30-43 years of age) undergoing induction of superovulation for assisted reproduction were studied. A blood sample was collected before and days 3, 8, and 12 during the induction of superovulation. A follicular fluid sample at the time of ovarian pick up was also collected. Serum and follicular fluid were assayed for inhibin B, activin A, and estradiol.

RESULTS

According to the successful follicular development women were divided in two groups: (A) responders (n = 10) and (B) poor responders (n = 6). Women of group A showed mean follicular fluid inhibin B levels higher than in group B (P = 0.001), while no significant difference for activin A levels was found. During induction of superovulation serum activin A levels did not change in both groups of women, while inhibin B and estradiol levels significantly increase only in responder women (P < 0.001). Serum inhibin B and estradiol levels correlated with follicles developed > or = 10 mm (P = 0.000).

CONCLUSIONS

Serum inhibin B is an effective marker of follicular development in infertile women undergoing induction of superovulation, and may represent a further marker for ovarian follicular capacity.

Gonadotropic control of secretion of dimeric inhibins and activin A by human granulosa-luteal cells in vitro

PURPOSE

It is well established that human granulosa cells and luteal cells express inhibin/activin subunit protein and secrete immunoreactive inhibin. The gonadotropic control of secretion of different molecular forms of inhibin and activin A by granulosa-luteal cells (G-LCs) was investigated using recently developed specific enzyme immunoassays (EIAs).

METHODS

Granulosa-luteal cells obtained at IVF egg pickup were cultured in a serum-free medium at 37 degrees C in a water-saturated incubator with 5% CO2 for up to 5 days. Experiments with varying concentrations of human FSH, hLH, and hCG were carried out.

RESULTS

FSH raised the secretion of inhibin A and pro-alpha C-containing inhibins after 24 and 48 hr in culture. Inhibin B was raised after 24 hr and activin A was raised after 48 hr of FSH treatment. LH treatment for 24 hr stimulated inhibin A, inhibin B, pro-alpha C, and activin A. hCG stimulated G-LC secretion of inhibin A after 48 hr and pro-alpha C after 24 hr. Paradoxically, inhibin B secretion was inhibited by 1 and 10 ng/ml hCG after 48 hr. Activin A was stimulated by hCG after 24 and 48 hr of incubation. G-LC secretion of estradiol and progesterone was also stimulated significantly by LH and hCG.

CONCLUSIONS

Secretion of dimeric inhibins and activin A is controlled differentially by gonadotropins.