Annie Benhaim

BMP system expression in GCs from polycystic ovary syndrome women and the in vitro effects of BMP4, BMP6, and BMP7 on GC steroidogenesis

BACKGROUND The bone morphogenetic proteins (BMPs) are growth factors involved in the folliculogenesis. Alteration in their expression may compromise the reproductive process in disease such as the polycystic ovary syndrome (PCOS). This study investigated the expression and role of granulosa cell (GC) BMP from normal cycling and PCOS women. METHODS AND RESULTS This prospective study was performed in GCs obtained from 14 patients undergoing IVF: i) six women with normal ovulatory cycles and tubal or male infertility and ii) eight women with PCOS. BMP2, BMP4, BMP5, BMP6, BMP7, and BMP8A and their receptors BMPR1A, BMPR1B, and BMPR2 were identified by RT-PCR in GCs from normally cycling and PCOS women. BMP4, BMP6, and BMP7 expressions were confirmed by immunohistochemistry. Quantitative transcript analysis showed the predominant expression of BMP6. In GCs from PCOS women, an overexpression of BMP6 (P<0.01) and BMPR1A mRNA (P<0.05) was observed. GC culture experiments demonstrated that basal estradiol (E₂) production was threefold higher but FSH-induced E₂ increment was twofold lower in PCOS compared with controls. In PCOS, BMP6 and BMP7 exerted a stimulatory effect on basal E₂ production while BMP4 and BMP6 inhibited FSH-induced E₂ production. FSH receptor and aromatase expression were not different between both groups. CONCLUSION The BMP system is expressed in human GCs from normal cycling and PCOS women. The BMP may be involved in reproductive abnormalities found in PCOS.

Aberrant adrenal sensitivity to vasopressin in adrenal tumours associated with subclinical or overt autonomous hypercortisolism: is this explained by an overexpression of vasopressin receptors?

Objective  Abnormal responsiveness to arginine vasopressin (AVP) was previously observed in cortisol‐producing adrenocortical tumours but the mechanism remains unclear. The aim of this study was to characterize the effect of AVP on cortisol secretion from adrenocortical tumours compared to normal human adrenal gland.

GnRH agonist and GnRH antagonist protocols in ovarian stimulation: differential regulation pathway of aromatase expression in human granulosa cells

Gonadotrophin-releasing hormone (GnRH) agonists and antagonists have been widely used to prevent premature LH surge during ovarian stimulation. However, studies have shown a significantly lower serum oestradiol concentration on the day of human chorionic gonadotrophin administration for cycles using GnRH antagonist. This study compared aromatase gene expression in granulosa lutein cells from 50 women randomly assigned to receive either GnRH agonist (group 1, n=28) or GnRH antagonist (group 2, n=22). The cellular mechanism involved in the observed effects was also investigated. GnRH antagonist treatment significantly affected serum oestradiol concentration (1894+/-138 versus 1074+/-63 pg/ml; P < or = 0.001), follicular-fluid oestradiol concentration in large follicles (18,565+/-2467 versus 10,184+/-1993 pg/ml; P < or = 0.05), aromatase activity (9600+/-1179 versus 5376+/-997 fmol/10(6) cells/h; P < or = 0.05) and mRNA aromatase/mRNA glyceraldehyde 3-phosphate dehydrogenase (15+/-3 versus 6+/-1; P < 0.05). Protein kinase C (PKC) activity in granulosa lutein cells from the GnRH antagonist group was 2.5-fold higher than in the GnRH agonist group. In-vitro experiments showed that selective down-regulation of PKC was only observed in GnRH-desensitized granulosa lutein cells. This report suggests that, in granulosa lutein cells, the modulation of the FSH-induced protein kinase A pathway by PKC was different in agonist versus antagonist cycles.

Transfert électif d’un embryon – le modèle scandinave

Limiting the number of embryos transferred from three to two does not reduce the high risk of twin pregnancy (between 21 and 40%). Scandinavian centers have proposed in the 2000s the elective single embryo transfer (eSET) as the only means to reduce maternal, neonatal and psychological consequences related to multiple births. Pooled results from prospective randomized controlled trials and prospective cohort studies comparing eSET and transfer of two embryos (DET) in a selected population have confirmed the almost complete disappearance of twins when eSET was effective but the compromising effect of eSET upon live birth rates was discussed. Optimizing the eSET overall pregnancy rate need to associate a freezing policy and to define risk factors for increased chance of multiple birth (patient age, diagnosis, number of top-embryos or unsuccessful attempts). The extension of eSET practice to an unselected population irrespective of embryo quality is still controversial. The choice between offering one cycle of SET or DET in an unselected patient population depends on the societys willingness to optimize the in vitro fertilization results according to a defined health care policy: the first one is the twins disappearance with reduced overall pregnancy rate and the second one is a reduced twin birth rate with maintain of the total pregnancy percentage. The real question is to define what percentage of twin pregnancy could be considered as acceptable.

Syndecan 1 represses cell growth and FSH responsiveness in human granulosa cells

Albeit devoid of intrinsic catalytic activity, the transmembrane heparan sulphate proteoglycan syndecan 1 plays critical roles in cellular processes such as extracellular matrix crosstalk, cytoskeletal organization, cell spreading, proliferation and differentiation. During the ovarian cycle, the expression of syndecan 1 in granulosa cells shows cyclic variation suggesting that it might fulfil specific roles in follicle development. To investigate its physiological roles on granulosa cells, syndecan 1 was overexpressed in human granulosa cell line KGN which retains features of granulosa cells from small antral follicle such as estradiol (E2) synthesis and low expression of functional FSH receptor (FSHR). We demonstrated that overexpression of syndecan 1 in immature granulosa cells (KGN-SDC1) induces a profound alteration in their intrinsic characteristics including enhanced spreading and attachment, both associated with a reduced growth rate. Flow cytometry analysis revealed that syndecan 1 overexpression increases the percentage of KGN cells in quiescent phase. This partial cell cycle exit is concordant with downregulated levels of CCND1 and CDK4 and upregulated expression of CDK inhibitor CDKN1A In parallel both unstimulated and FSH-induced E2 synthesis are reduced in KGN-SDC1 through both repression of CYP19A1 and FSHR mRNA associated with decreased levels of potential regulators NR5A1 and ESR2 Additionally, we provide evidence that transient cAMP accumulation reduction in cells overexpressing syndecan 1 is accompanied by an increase in cAMP-hydrolysing PDE activity. Our results demonstrated that syndecan 1 might regulate differentiation of granulosa cells and follicular development by means of various mechanisms involving morphological changes, control of signalling pathways and alterations in gene expressions.Free French abstract: A French translation of this abstract is freely available at http://www.reproduction-online.org/content/153/6/797/suppl/DC1.Reproduction.