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Adult intestinal stem cells are located at the bottom of crypts of Lieberkühn, where they express markers such as LGR5.sup.1,2 and fuel the constant replenishment of the intestinal epithelium.sup.1. Although fetal LGR5-expressing cells can give rise to adult intestinal stem cells.sup.3,4, it remains unclear whether this population in the patterned epithelium represents unique intestinal stem-cell precursors. Here we show, using unbiased quantitative lineage-tracing approaches, biophysical modelling and intestinal transplantation, that all cells of the mouse intestinal epithelium--irrespective of their location and pattern of LGR5 expression in the fetal gut tube--contribute actively to the adult intestinal stem cell pool. Using 3D imaging, we find that during fetal development the villus undergoes gross remodelling and fission. This brings epithelial cells from the non-proliferative villus into the proliferative intervillus region, which enables them to contribute to the adult stem-cell niche. Our results demonstrate that large-scale remodelling of the intestinal wall and cell-fate specification are closely linked. Moreover, these findings provide a direct link between the observed plasticity and cellular reprogramming of differentiating cells in adult tissues following damage.sup.5-9, revealing that stem-cell identity is an induced rather than a hardwired property. Lineage tracing, biophysical modelling and intestinal transplantation approaches are used to demonstrate that, in the mouse fetal intestinal epithelium, cells are highly plastic with respect to cellular identity and, independent of LGR5 expression and cell position, can contribute to the adult stem cell compartment., Author(s): Jordi Guiu [sup.1] , Edouard Hannezo [sup.2] [sup.3] , Shiro Yui [sup.1] [sup.13] , Samuel Demharter [sup.1] , Svetlana Ulyanchenko [sup.1] , Martti Maimets [sup.1] , Anne Jørgensen [sup.4] [...]

Introduction: Administration of dexamethasone (DEX) has been used experimentally to suppress androgenization of external genitalia in 46,XX fetuses with congenital adrenal hyperplasia. Despite this, the prenatal biological mechanism-of-action of DEX on fetal development is not known. This study aimed to examine direct effects of DEX on human fetal adrenal (HFA) steroidogenic activity including possible effects on the subsequent response to ACTH-stimulation. Methods: Human fetal adrenal (HFA) tissue from 30 fetuses (1st trimester) were cultured ex vivo with A) DEX (10 µm) for 14 days, or B) DEX (10 µm) for 10 days followed by ACTH (1 nM) for 4 days. DEX-mediated effects on HFA morphology, viability, and apoptosis (immunohistochemistry), gene expression (quantitative PCR), and steroid hormone secretion (LC-MS/MS) were investigated. Results: DEX-treatment caused decreased androstenedione (p<0.05) and increased cortisol (p<0.01) secretion suggesting that direct effects on the adrenal gland may contribute to the negative feedback on the hypothalamicpituitary-adrenal axis in vivo. An altered response to ACTH stimulation in HFA pre-treated with DEX included increased androgen (p<0.05) and reduced cortisol production (p<0.05), supporting clinical observations of a temporary decreased ACTH-response following prenatal DEX-treatment. Additionally, the secretion of corticosterone was decreased (p<0.0001) following ACTH-stimulation in the initially DEX-treated HFAs. Discussion: The observed effects suggest that prenatal DEX-treatment can cause direct effects on HFA steroidogenesis and in the subsequent response to ACTH-stimulation. This may indicate a requirement for careful monitoring of adrenal function in prenatally DEX-treated neonates, with particular focus on their mineralocorticoid levels. [ABSTRACT FROM AUTHOR]

Although assisted reproductive technology has reduced the need for surgery for women with infertility, there is evidence to support, that targeted reproductive surgery can improve fertility and pregnancy outcomes. In the last decades, increased access to minimal invasive surgery has brought a new era to reproductive surgery. An integration of reproductive surgery in the fertility treatment is therefore recommended. The patient should be offered detailed information regarding the pros and cons before the surgical treatment, as the evidence in the field is sparse, which is discussed in this review.