Tridimensional Visualization and Analysis of Early Human Development.

Generating a precise cellular and molecular cartography of the human embryo is essential to our understanding of the mechanisms of organogenesis in normal and pathological conditions. Here, we have combined whole-mount immunostaining, 3DISCO clearing, and light-sheet imaging to start building a 3D cellular map of the human development during the first trimester of gestation. We provide high-resolution 3D images of the developing peripheral nervous, muscular, vascular, cardiopulmonary, and urogenital systems. We found that the adult-like pattern of skin innervation is established before the end of the first trimester, showing important intra- and inter-individual variations in nerve branches. We also present evidence for a differential vascularization of the male and female genital tracts concomitant with sex determination. This work paves the way for a cellular and molecular reference atlas of human cells, which will be of paramount importance to understanding human development in health and disease. PAPERCLIP.

Development of the neurons controlling fertility in humans: new insights from 3D imaging and transparent fetal brains.

Fertility in mammals is controlled by hypothalamic neurons that secrete gonadotropin-releasing hormone (GnRH). These neurons differentiate in the olfactory placodes during embryogenesis and migrate from the nose to the hypothalamus before birth. Information regarding this process in humans is sparse. Here, we adapted new tissue-clearing and whole-mount immunohistochemical techniques to entire human embryos/fetuses to meticulously study this system during the first trimester of gestation in the largest series of human fetuses examined to date. Combining these cutting-edge techniques with conventional immunohistochemistry, we provide the first chronological and quantitative analysis of GnRH neuron origins, differentiation and migration, as well as a 3D atlas of their distribution in the fetal brain. We reveal not only that the number of GnRH-immunoreactive neurons in humans is significantly higher than previously thought, but that GnRH cells migrate into several extrahypothalamic brain regions in addition to the hypothalamus. Their presence in these areas raises the possibility that GnRH has non-reproductive roles, creating new avenues for research on GnRH functions in cognitive, behavioral and physiological processes.

[Chronic disease and sexuality, a taboo for caregivers]. / Maladie chronique et sexualité, un tabou pour les soignants.

Chronic disease impacts on patients' quality of life and in particular their sexuality. The consequences on their sexual quality of life are both physical and psychological and also affect their relationship as a couple. The issue is still taboo with too few caregivers prepared to address it.

Novel role for anti-Müllerian hormone in the regulation of GnRH neuron excitability and hormone secretion.

Anti-Müllerian hormone (AMH) plays crucial roles in sexual differentiation and gonadal functions. However, the possible extragonadal effects of AMH on the hypothalamic-pituitary-gonadal axis remain unexplored. Here we demonstrate that a significant subset of GnRH neurons both in mice and humans express the AMH receptor, and that AMH potently activates the GnRH neuron firing in mice. Combining in vivo and in vitro experiments, we show that AMH increases GnRH-dependent LH pulsatility and secretion, supporting a central action of AMH on GnRH neurons. Increased LH pulsatility is an important pathophysiological feature in many cases of polycystic ovary syndrome (PCOS), the most common cause of female infertility, in which circulating AMH levels are also often elevated. However, the origin of this dysregulation remains unknown. Our findings raise the intriguing hypothesis that AMH-dependent regulation of GnRH release could be involved in the pathophysiology of fertility and could hold therapeutic potential for treating PCOS.

SEMA3A, a gene involved in axonal pathfinding, is mutated in patients with Kallmann syndrome.

Kallmann syndrome (KS) associates congenital hypogonadism due to gonadotropin-releasing hormone (GnRH) deficiency and anosmia. The genetics of KS involves various modes of transmission, including oligogenic inheritance. Here, we report that Nrp1(sema/sema) mutant mice that lack a functional semaphorin-binding domain in neuropilin-1, an obligatory coreceptor of semaphorin-3A, have a KS-like phenotype. Pathohistological analysis of these mice indeed showed abnormal development of the peripheral olfactory system and defective embryonic migration of the neuroendocrine GnRH cells to the basal forebrain, which results in increased mortality of newborn mice and reduced fertility in adults. We thus screened 386 KS patients for the presence of mutations in SEMA3A (by Sanger sequencing of all 17 coding exons and flanking splice sites) and identified nonsynonymous mutations in 24 patients, specifically, a frameshifting small deletion (D538fsX31) and seven different missense mutations (R66W, N153S, I400V, V435I, T688A, R730Q, R733H). All the mutations were found in heterozygous state. Seven mutations resulted in impaired secretion of semaphorin-3A by transfected COS-7 cells (D538fsX31, R66W, V435I) or reduced signaling activity of the secreted protein in the GN11 cell line derived from embryonic GnRH cells (N153S, I400V, T688A, R733H), which strongly suggests that these mutations have a pathogenic effect. Notably, mutations in other KS genes had already been identified, in heterozygous state, in five of these patients. Our findings indicate that semaphorin-3A signaling insufficiency contributes to the pathogenesis of KS and further substantiate the oligogenic pattern of inheritance in this developmental disorder.

Differential distribution of erbB receptors in human glioblastoma multiforme: expression of erbB3 in CD133-positive putative cancer stem cells.

Glioblastomas are the most common primary central nervous system tumors in adults, and they remain resistant to current treatments. erbB1 signaling is frequently altered in glioblastomas, suggesting thaterbB receptor family members may represent targets for molecular therapy. We performed a comprehensive analysis of erbB receptor and ligand expression profiles in a panel of 9 glioblastomas andcompared them to nonneoplastic cerebral tissue containing neocortex and adjacent white matter. Quantitative reverse transcription-polymerase chain reaction and Western blot analysis showed that erbB1signaling and erbB2 receptors exhibited highly variable deregulation profiles in the tumors, with patterns ranging from underexpression to overexpression; in contrast, erbB3 and erbB4 were downregulated. We next performed immunohistochemistry to determinethe distribution patterns of erbB receptors among the main neuralcell types in the tumors with special reference to the putative tumor stem cell population. Results revealed intertumoral and intratumoral heterogeneity in all 4 erbB expression profiles, but each receptor exhibited a distinct distribution pattern among glial fibrillary acidic protein-, Olig2-, NeuN-, and CD133-positive populations. Although erbB1 immunoreactivity was detected in only small subsets of CD133-positive putative tumor stem cells, erbB3 immunoreactivity was prominent in this population, suggesting that erbB3 may represent a new potential therapeutic target.

[Benefit of the Internet as an information tool in case of oral contraceptive miss. Survey of 1964 women visiting the website www.g-oubliemapilule.com]. / Intérêt d'Internet comme outil d'information en cas d'oubli de pilule en médecine générale. Enquête chez 1964 femmes consultant le site www.g-oubliemapilule.com.

The aim of the study is to evaluate the utility of the website http://www.g-oubliemapilule.com/ that contains the recommendations of the French Haute Autorité de santé in case of oral contraceptive pill missing. This epidemiologic prospective study was conducted using an online questionnaire available at http://www.g-oubliemapilule.com/. The results emphasize the poor quality of information provided by the physicians. 40% of the physicians don't provide information about what to do in case of oral contraceptive pill missing during the first medical visit for oral contraceptive prescription and the physicians don't inquire about oral contraceptive pill missing during the follow-up in 3/4 of the cases. Furthermore, when women find information about what to do in case of oral contraceptive pill missing, a majority of them won't follow the advice provided even if it is fully understood. 60% of the women who should use the condom during the 7 days following the oral contraceptive pill missing don't use it and 86% of the women who should use the emergency contraceptive pill don't use it. The reason mostly invoked (1/3 of the cases) to support that behaviour is the assumption that the risk of pregnancy is too low. The results help to understand the gap between theoretical efficacy (Pearl Index: 0.3%) and real efficacy (8%) of the oral contraceptive pill. Finally, the website http://www.g-oubliemapilule.com/ is a useful well understood additional tool but can't replace the medical follow-up.

Differential erbB signaling in astrocytes from the cerebral cortex and the hypothalamus of the human brain.

Studies in rodents have shown that astroglial erbB tyrosine kinase receptors are key regulatory elements in neuron-glia communication. Although both astrocytes and deregulation of erbB functions have been implicated in the pathogenesis of many common human brain disorders, erbB signaling in native human brain astrocytes has never been explored. Taking advantage of our ability to perform primary cultures from the cortex and the hypothalamus of human fetuses, we conducted a thorough analysis of erbB signaling in human astrocytes. We showed that human cortical astrocytes express erbB1, erbB2, and erbB3, whereas human hypothalamic astrocytes express erbB1, erbB2, and erbB4 receptors. Ligand-dependent activation of different erbB receptor heterodimeric complexes in these two populations of astrocytes translated into different morphological and proliferative responses. Although morphological plasticity was more pronounced in hypothalamic astrocytes than in cortical astrocytes, the former showed a lower mitogenic potential. Decreasing erbB4 expression via siRNA-mediated gene knockdown revealed that erbB4 constitutively restrains basal proliferative activity in hypothalamic astrocytes. We further show that treatment of human astrocytes with a protein kinase C activator results in rapid tyrosine phosphorylation of erbB receptors that involves cleavage of endogenous membrane bound erbB ligands by metalloproteinases. Together, these results indicate that erbB signaling in primary human brain astrocytes is functional, region-specific, and can be activated in a paracrine and/or autocrine manner. In addition, by revealing that some aspects of astroglial erbB signaling are different between human and rodents, our results provide a molecular framework to explore the potential involvement of astroglial erbB signaling deregulation in human brain disorders.

Factors influencing changes in bone mineral density in patients with anorexia nervosa-related osteoporosis: the effect of hormone replacement therapy.

The purpose of this longitudinal study was to evaluate factors affecting changes in bone mineral density (BMD) in patients with anorexia nervosa (AN) and osteoporosis and, more particularly, to assess the benefits of hormone replacement therapy (HRT) on BMD in these patients. Our study involved 45 AN patients, 12 of whom had been treated by HRT for 2 years following a diagnosis of osteoporosis by densitometry (WHO criteria). Patients' mean age was 25.3 +/- 6.7 years. Mean duration of illness was 5.7 +/- 5.3 years. Serum calcium and phosphate were measured at baseline, as were bone remodeling markers. Osteodensitometry by dual-energy X-ray absorptiometry was performed at inclusion and after 2 years. After 2 years, no significant differences were observed between spine, femoral neck, and total hip BMDs either in the HRT group (P = 0.3, P = 0.59, P = 0.58) or in the nontreatment group (P = 0.17, P = 0.68, P = 0.98). Moreover, there were no significant differences between the two groups when changes in spine, femoral neck, and total hip BMDs at 2 years were compared (P = 0.72, P = 0.95, P = 0.58). In both groups, change in weight at 1 year correlated with change in spine BMD at 2 years (r = 0.35, P = 0.04) and change in total-hip BMD at 2 years (r = 0.35, P = 0.04) but not with change in femoral neck BMD at 2 years. Patients with a body mass index (BMI) > or = 17 kg/m(2) at 2 years showed a significant increase in total-hip BMD when compared with patients with a BMI < 17 kg/m(2) (+4.4% +/- 6.7 vs. -0.5% +/- 6.01, P = 0.03). No significant differences were observed for spine and femoral neck BMD. In patients who had recovered their menstrual cycle, significant increases were observed in spine BMD (+4% +/- 6.3 vs. -1.9% +/- 5.6, P = 0.008), femoral neck BMD (+3% +/- 6.2 vs. -2.4% +/- 8, P = 0.05), and total-hip BMD (+3% +/- 7.1 vs. -3.7% +/- 10, P = 0.04). Prevention of bone loss at 2 years in AN patients treated by HRT was not confirmed in this study. We did confirm that increase in weight at 1 year was the most predictive factor for the improvement of spine and hip BMD at 2 years.

Evaluation of bone loss and its mechanisms in anorexia nervosa.

The purpose of this cross-sectional study was to assess the extent of and mechanisms involved in bone loss in anorexia nervosa patients. We compared 113 anorexia nervosa patients (mean age 25 +/- 8 years, mean duration of disease 5.7 +/- 6.1 years) with 21 age-matched controls. Mean duration of amenorrhea was 3.2 +/- 4.7 years. We measured serum calcium and phosphate; bone remodeling markers (osteocalcin, bone-specific alkaline phosphatase [BSAP], serum crosslaps [CTX], and carboxyl-terminal telopeptide of type I collagen [ICTP]); follicle-stimulating hormone and luteinizing hormone levels; and estradiol (ultrasensitive assay), cortisol, urinary free cortisol, thyroid function, prolactin, and nutritional factors (insulin-like growth factor I [IGF-I], IGF binding protein 3 [IGFBP3]). In controls, only bone remodeling markers and nutritional factors were measured. Osteodensitometry was also performed on both patients and controls. Weight and body mass index (BMI) were significantly lower in anorexia nervosa patients than in controls (P < 0.0001). No significant differences were observed in biological indicators except for IGF-I, which was lower in anorexia nervosa patients (0.9 +/- 0.4 UI/mL) than in controls (1.5 +/- 0.4 UI/mL) (P < 0.0001). Densitometric measurements at three sites were significantly lower in anorexia nervosa patients and correlated with duration of disease and amenorrhea and with IGF-I at the hip only (P < 0.01). In the study population, osteoporosis was observed in 24 patients (21%) and osteopenia in 54 patients (48%). Patients with osteoporosis were significantly older and had longer disease and amenorrhea durations; lower weight and BMI; higher alkaline phosphatase, BSAP, and osteocalcin; and lower serum ICTP, IGF-I, and IGFBP3. All of these differences were significant and remained so even after multiple adjustments were made, except for IGF-I (P = 0.21). When multivariate analysis was performed, we found that age at onset of amenorrhea, weight, alkaline phosphatase, urinary free cortisol, and serum estradiol concentration accounted for 54% of the variance in spinal bone mineral density (BMD). Duration of amenorrhea, alkaline phosphatase, and weight explained 46.6% of the variance in femoral neck BMD. Duration of amenorrhea, IGF-I, and ICTP levels accounted for 38.6% of the variance observed in total hip BMD. The etiology of bone loss in patients with anorexia nervosa is multifactorial. Hypoestrogenia alone cannot account for this loss, and nutritional factors, IGF-I concentrations in particular, seem to play an important role.

Bone loss associated with anorexia nervosa.

The objective of this study was to evaluate the epidemiology, diagnosis, pathophysiology, and treatment of bone loss related to anorexia nervosa. Earlier onset and longer duration of anorexia nervosa are associated with more severe bone loss. Osteoporosis develops in 38-50% of cases. Bone mineral density measurement by dual-energy X-ray absorptiometry is useful for assessing bone mass, and bone marker assays provide information on bone turnover. Bone loss in anorexia nervosa is probably multifactorial. Estrogen deficiency was long felt to be the major factor. However, in contrast to postmenopausal osteoporosis, bone loss associated with anorexia nervosa is related mainly to inadequate bone formation, with only a slight increase in bone resorption. This suggests a role for nutritional factors, such as disturbances in the growth hormone-somatomedin C axis (GH/IGF-I) related to malnutrition. The best treatment strategy for correcting bone mass in patients with anorexia nervosa is not agreed on. Resumption of menstrual cycles and weight gain seem necessary but not always sufficient. Studies found no benefits with estrogen therapy, but this was usually given as estrogen-progestin contraceptives. No vast studies evaluating hormone replacement therapy have been reported. Bone formation enhancers such as IGF-I seem to provide the best results, most notably when used in combination with estrogens. This suggests that complex treatment strategies combining bone formation enhancers and bone resorption inhibitors may deserve evaluation.