Changes in circulating forms of anti-Muüllerian hormone and androgens in women with and without PCOS: a systematic longitudinal study throughout pregnancy.

STUDY QUESTION: What are the changes in serum concentration of total and cleaved anti-Muüllerian hormone (AMH) molecular forms and of androgens before and throughout pregnancy in women with and without polycystic ovary syndrome (PCOS) in a longitudinal follow-up investigation? SUMMARY ANSWER: Serum levels of total and cleaved AMH are higher from preconception to the third trimester of pregnancy in women with PCOS as compared to controls, whereas testosterone and androstenedione levels are higher in women with PCOS than in control women before pregnancy and during the second and third trimester of pregnancy. WHAT IS KNOWN ALREADY: Cross-sectional or partial longitudinal studies have shown higher AMH and androgen levels in pregnant women with PCOS as compared with non-PCOS women. To date, no complete longitudinal dynamic monitoring of the circulating forms of AMH and androgens from pre-conception to the third trimester of pregnancy have compared women with and without PCOS. STUDY DESIGN, SIZE, DURATION: This systematic prospective quarterly longitudinal monocentric study was a comparative follow-up of 30 women with PCOS and 29 controls before and during pregnancy from April 2019 to July 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women aged 18-43 years with a pre-conception measurement of AMH were included during the first trimester of a singleton pregnancy. The PCOS group was defined according to the Rotterdam diagnostic criteria. The control group patients included in the study had normal ovarian reserves. Circulating total and cleaved AMH, and serum estradiol, LH, and androgen levels were measured during the first, second, and third trimester of pregnancy in all study participants. MAIN RESULTS AND THE ROLE OF CHANCE: Before pregnancy, patients with PCOS had higher levels of AMH than controls. The total and cleaved AMH forms were significantly higher in women with PCOS than controls from pre-conception to the third trimester of pregnancy (all P < 0.001). Androgens (total testosterone and androstenedione) were higher in women with PCOS than controls from mid-pregnancy onwards. LIMITATIONS, REASONS FOR CAUTION: Our control population was a population of infertile women with no ovarian problems but most of them had undergone ART treatments to achieve pregnancy. WIDER IMPLICATIONS OF THE FINDINGS: These results strengthen the hypothesis that gestational hyperandrogenism as well as exposure to elevated AMH levels in utero could be driving forces predisposing female progeny to develop PCOS. STUDY FUNDING/COMPETING INTEREST(S): Funding was provided by INSERM, France (grant number U1172) and the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program, ERC-2016-CoG to P.G. grant agreement n° 725149/REPRODAMH. The authors have nothing to declare. TRIAL REGISTRATION NUMBER: NCT03483792.

[How to deal with the different serum AMH kits in France in 2017?] / Les différentes trousses de dosage d'AMH en France en 2017 : comment s'y retrouver en pratique clinique quotidienne ?

Serum AMH measurement became a key element in clinical practice, especially before using Assisted reproductive techniques (ART). However, many AMH kits exist giving different AMH results, leading to a confusion in their interpretation. Until recently, only manual ELISA kits existed (mainly Gen II Beckman, EIA/AMH Immunotech and two Anshlab kits) reporting non-interchangeable results. High and low AMH cut-off values, mainly useful to adapt therapeutics in ART, were different between kits. Since the end of 2014, the arrival of two automatic assays (Access Dxi Beckman and AMH Elecsys Roche) seems to improve the sensitivity and the reproducibility of AMH measurement. It could simplify the interpretation of AMH values and improve our clinical choices. This review synthetizes the main comparisons between the different AMH kits available in 2017 to help clinicians in their daily clinical practice.

Factors involved in the migration of neuroendocrine hypothalamic neurons.

Neuroendocrine control of physiological functions needs a complex developmental organisation of the hypothalamic parvicellular neurons, which synthesise and release hypophysiotropic hormones. Among the hypothalamic neuroendocrine cells, Gonadotropin-releasing hormone (GnRH) neurons represent a unique class; they are generated in the olfactory placode and, during embryonic life, migrate to the septo/hypothalamic region along terminal and vomeronasal nerves. At this level GnRH neurons undergo terminal differentiation and start to release GnRH to modulate the secretion of pituitary gonadotropins. All these steps are under the strict control of several developmental cues and their defect might represent a cause of clinical disorders. A number of factors have been proposed to be involved in the migration of GnRH neurons, but their role is still unclear. By using gene knockout techniques it has been found that mice carrying a targeted deletion of Ebf2 gene, a component of Olf/Ebf bHLH transcription factors, show a defective migration of GnRH neurons, providing the first evidence of a mouse model of such defect. Since the investigation of GnRH neurons is hindered by their peculiar anatomical distribution, other studies has been forwarded by the availability of immortalized GnRH-expressing neurons (GN11 cells) that retain a strong chemomigratory response "in vitro". Among the factors analysed, we found that hepatocyte growth factor/scatter factor (HGF/SF) and vascular endothelial growth factor (VEGF) induce specific chemotaxis of GN 11 neurons, suggesting that migratory signals can arise from nasal mesenchyme and from the concomitant vasculogenesis. Finally, anosmin-1 (the product of the gene responsible of the X-linked form of Kallmann's disease) was found to induce a significant chemotactic response of GN11 cells, confirming a permissive/instructive role of KAL1 gene product in the migratory behaviour of GnRH neurons. In conclusion, the migration of the GnRH neurons appears to be a complex process, which involves the interplay of multiple molecular cues. These studies may provide new insights on the etiopathogenesis of the large proportion of reproductive dysfunctions that affect humans and could provide novel insights on common biochemical events controlling neuronal development and migration.

Hepatocyte growth factor/scatter factor facilitates migration of GN-11 immortalized LHRH neurons.

The molecular cues regulating the migratory process of LHRH neurons from the olfactory placode into the brain are not well known, but gradients of chemotropic and chemorepellent factors secreted by the targets are likely to play a key role in guidance mechanisms. Hepatocyte growth factor/scatter factor (HGF/SF) is a pleiotropic cytokine inducing cell migration. It is involved in a variety of developmental processes through interaction with its receptor c-Met. Here we show that c-Met-antibody labels LHRH migrating neurons in the olfactory mesenchyme of E12 mouse and analyze the potential chemotropic effect of HGF/SF on two immortalized LHRH cell lines, GT1-7 and GN11, isolated from tumors developed in the hypothalamus and in the olfactory bulb, respectively. By RT-PCR analysis, Western blotting, and immunocytochemistry, we provide evidence for a high level of c-Met expression in GN11, but not in GT1-7, cells. In addition, HGF/SF treatment promotes specific migratory activity of GN11 cells, as demonstrated by collagen gel assay, time-lapse video microscopy, and Boyden's chamber experiments. Such promotion is inhibited by the neutralizing antibody. The data reported here represent the first direct evidence of a chemotactic effect of HGF/SF on immortalized LHRH neurons.

Proliferation and migration of receptor neurons in the vomeronasal organ of the adult mouse.

Cell proliferation and differentiation in the vomeronasal organ of the adult mouse was studied by bromodeoxyuridine (BrdU) immunohistochemistry coupled to immunostaining for specific markers of the differentiation, such as carnosine, B50-GAP43 (growth-associated protein) and stathmin. The present study shows that three populations of proliferating elements are present in the vomeronasal sensory epithelium that are placed, respectively, in the supporting cell layer, at the boundaries between the sensory epithelium (S-VNO) and the non-sensory (NS-VNO) and in the basal region of the S-VNO. The number of dividing cells at the boundaries of the S-VNO is by far prevailing. Few proliferating cells located adjacent to the basal membrane are, however, present 1 day after BrdU inoculations. Seven days after BrdU treatment immunopositive nuclei were detected in more central regions of the VNO and at longer survival times they were also positive to carnosine, a marker of fully differentiated neurons. In conclusion, the present results suggest that at least two populations of VNO neuronal precursors are responsible for cell replacement throughout life.

Apoptosis in the development of the mouse olfactory epithelium.

Apoptotic cells were detected in the mouse olfactory epithelium (OE) at different embryonic and postnatal stages by in situ nick translation (ISNT) and Tdt-mediated dUTP nick end-labeling (TUNEL) techniques. During development, the apoptotic process presented two peaks. One at E12 during the invagination of the olfactory placode and the second at E16 corresponding to olfactory axon synaptogenesis. Then, from E18, a sharp decrease in the number of apoptotic cells was observed and at E19 the apoptotic index reached low values that were maintained in postnatal stages, P1 and P8, and in the adult. Apoptotic nuclei belonged to mature as well as immature olfactory receptor neurons (ORNs). Indeed, double-labeling experiments evidenced apoptotic neurons immunopositive for olfactory marker protein (OMP), carnosine and GAP-43. According to our data, two apoptotic phases occur during early development. One is involved in the morphogenesis of the OE when this last is not yet, or poorly, connected to its target, the olfactory bulb (OB). The second peak of apoptosis is more closely dependent on the interplay between OE and OB.