Brougham M.F.H.,Royal Hospital for Sick Children |
Crofton P.M.,Royal Hospital for Sick Children |
Johnson E.J.,Royal Hospital for Sick Children |
Evans N.,Medical Research Council Human Reproductive science Unit |
And 2 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2012
Context: Cytotoxic treatment may accelerate depletion of the primordial follicle pool, leading to impaired fertility and premature menopause. Assessment of ovarian damage in prepubertal girls is not currently possible, but Anti-Müllerian Hormone (AMH) is a useful marker of ovarian reserve in adults. Objective: The objective of the study was to prospectively evaluate AMH measurement in children as a marker of ovarian toxicity during cancer treatment. Design and Setting: This was a prospective, longitudinal study at a University Hospital. Patients: Twenty-two females (17 prepubertal), median age 4.4 yr (range 0.3-15 yr), were recruited before treatment for cancer. Main Outcome Measures: AMH, inhibin B, and FSH at diagnosis, after each chemotherapy course and during follow-up, were measured. Risk of gonadotoxicity was classified as low/medium (n =13) or high (n=9) based on chemotherapy agent, cumulative dose, and radiotherapy involving the ovaries. Results: Pretreatment AMH was detectable across the age range studied. AMH decreased progressively during chemotherapy (P < 0.0001) in both prepubertal and pubertal girls, becoming undetectable in 50% of patients, with recovery in the low/medium risk groups after completion of treatment. In the high-risk group, AMH became undetectable in all patients and showed no recovery. Inhibin B was undetectable in most patients before treatment and, with FSH, showed no clear relationship to treatment. Conclusion: AMH is detectable in girls of all ages and falls rapidly during cancer treatment in both prepubertal and pubertal girls. Both the fall during treatment and recovery thereafter varied with risk of gonadotoxicity. AMHis therefore a clinically useful marker of damage to the ovarian reserve in girls receiving treatment for cancer. Copyright © 2012 by The Endocrine Society.
Fraser H.M.,Medical Research Council Human Reproductive science Unit |
Hastings J.M.,Medical Research Council Human Reproductive science Unit |
Allan D.,Medical Research Council Human Reproductive science Unit |
Morris K.D.,Medical Research Council Human Reproductive science Unit |
And 2 more authors.
Endocrinology | Year: 2012
Using specific inhibitors established that angiogenesis in the ovarian follicle and corpus luteum is driven by vascular endothelial growth factor. Recently, it has been demonstrated that the Notch ligand, delta-like ligand 4 (Dll4) negatively regulates vascular endothelial growth factor-mediated vessel sprouting and branching. To investigate the role of Dll4 in regulation of the ovarian vasculature, we administered a neutralizing antibody to Dll4 to marmosets at the periovulatory period. The vasculature was examined on luteal d 3 or d 10: angiogenesis was determined by incorporation of bromodeoxyuridine, staining for CD31 and cell death by staining for activated caspase-3. Ovulatory progesterone rises were monitored to determine effects of treatment on luteal function and time to recover normal cycles in a separate group of animals. Additionally, animals were treated in the follicular or midluteal phase to determine effects of Dll4 inhibition on follicular development and luteal function. Controls were treated with human IgG (Fc). Corpora lutea from marmosets treated during the periovulatory period exhibited increased angiogenesis and increased vascular density on luteal d 3, but plasma progesterone was significantly suppressed. By luteal d 10, corpora lutea in treated ovaries were significantly reduced in size, with involution of luteal cells, increased cell death, and suppressed plasma progesterone concentrations. In contrast, initiation of anti-Dll4 treatment during the midluteal phase produced only a slight suppression of progesterone for the remainder of the cycle. Moreover, Dll4 inhibition had no appreciable effect on follicular development. These results show that Dll4 has a specific and critical role in the development of the normal luteal vasculature. Copyright © 2012 by The Endocrine Society.
Ramaesh T.,Queens Medical Research Institute |
Logie J.J.,Queens Medical Research Institute |
Roseweir A.K.,Medical Research Council Human Reproductive science Unit |
Millar R.P.,Medical Research Council Human Reproductive science Unit |
And 4 more authors.
Endocrinology | Year: 2010
Recent studies suggest that kisspeptin (a neuropeptide central to the regulation of gonadotrophin secretion) has diverse roles in human physiology, including a putative role in implantation and placental function. Kisspeptin and its receptor are present in human blood vessels, where they mediate vasoconstriction, and kisspeptin is known to inhibit tumor metastasis and trophoblast invasion, both processes involving angiogenesis. We hypothesized that kisspeptin contributes to the regulation of angiogenesis in the reproductive system. The presence of the kisspeptin receptor was confirmed in human placental blood vessels and human umbilical vein endothelial cells (HUVEC) using immunochemistry. The ability of kisspeptin-10 (KP-10) (a shorter biologically active processed peptide) to inhibit angiogenesis was tested in explanted human placental arteries and HUVEC using complementary ex vivo and in vitro assays. KP-10 inhibited new vessel sprouting from placental arteries embedded in Matrigel and tube-like structure formation by HUVEC, in a concentration-dependent manner. KP-10 had no effect on HUVEC viability or apoptosis but induced concentration-dependent inhibition of proliferation and migration. In conclusion, KP-10 has antiangiogenic effects and, given its high expression in the placenta,maycontribute to the regulation of angiogenesis in this tissue. Copyright © 2010 by The Endocrine Society.
Willems A.,Catholic University of Leuven |
Batlouni S.R.,São Paulo State University |
Esnal A.,Medical Research Council Human Reproductive science Unit |
Swinnen J.V.,Catholic University of Leuven |
And 5 more authors.
PLoS ONE | Year: 2010
The observation that mice with a selective ablation of the androgen receptor (AR) in Sertoli cells (SC) (SCARKO mice) display a complete block in meiosis supports the contention that SC play a pivotal role in the control of germ cell development by androgens. To delineate the physiological and molecular mechanism responsible for this control, we compared tubular development in pubertal SCARKO mice and littermate controls. Particular attention was paid to differences in SC maturation, SC barrier formation and cytoskeletal organization and to the molecular mediators potentially involved. Functional analysis of SC barrier development by hypertonic perfusion and lanthanum permeation techniques and immunohistochemical analysis of junction formation showed that SCARKO mice still attempt to produce a barrier separating basal and adluminal compartment but that barrier formation is delayed and defective. Defective barrier formation was accompanied by disturbances in SC nuclear maturation (immature shape, absence of prominent, tripartite nucleoli) and SC polarization (aberrant positioning of SC nuclei and cytoskeletal elements such as vimentin). Quantitative RT-PCR was used to study the transcript levels of genes potentially related to the described phenomena between day 8 and 35. Differences in the expression of SC genes known to play a role in junction formation could be shown from day 8 for Cldn11, from day 15 for Cldn3 and Espn, from day 20 for Cdh2 and Jam3 and from day 35 for ZO-1. Marked differences were also noted in the transcript levels of several genes that are also related to cell adhesion and cytoskeletal dynamics but that have not yet been studied in SC (Actn3, Ank3, Anxa9, Scin, Emb, Mpzl2). It is concluded that absence of a functional AR in SC impedes the remodeling of testicular tubules expected at the onset of spermatogenesis and interferes with the creation of the specific environment needed for germ cell development. © 2010 Willems et al.
Herr D.,University of Ulm |
Fraser H.M.,Medical Research Council Human Reproductive science Unit |
Konrad R.,University of Ulm |
Holzheu I.,University of Ulm |
And 2 more authors.
Fertility and Sterility | Year: 2013
Objective: To study the functional interactions of junctional proteins acting as regulators of vascular permeability in the human corpus luteum. We investigated the role of vascular endothelial (VE)-cadherin, nectin 2, and claudin 5 as controllers of vascular endothelial cell permeability. Design: Performing immunohistochemical dual staining, we colocalized the above-mentioned proteins in the human corpus luteum. Setting: Not applicable. Patient(s): Not applicable. Intervention(s): Not applicable. Main Outcome Measure(s): Using a granulosa-endothelial coculture system, we revealed that hCG-treatment down-regulates VE-cadherin, nectin 2, and claudin 5 in endothelial cells via vascular endothelial growth factor (VEGFA). Result(s): Furthermore, the interaction of VE-cadherin, nectin 2, and claudin 5 was investigated by silencing these proteins that perform siRNA knockdown. Interestingly, knockdown of VE-cadherin and claudin 5 induced a decrease of the respective other protein. This down-regulation was associated with changed rates of vascular permeability: hCG induced a VEGFA-dependent down-regulation of VE-cadherin, nectin 2, and claudin 5, which increased the endothelial permeability in the coculture system. Furthermore, knockdown of VE-cadherin, nectin-2, and claudin 5 also resulted in a consecutive increase of endothelial permeability for each different protein. Conclusion(s): These results demonstrate for the first time that VE-cadherin, nectin 2, and claudin 5 are involved in the regulation of vascular permeability in a mutually interacting manner, which indicates their prominent role for the functionality of the human corpus luteum. © 2013 American Society for Reproductive Medicine.
PubMed | Medical Research Council Human Reproductive science Unit
Type: | Journal: Brain research | Year: 2010
Kisspeptin has recently been identified as a key neuroendocrine gatekeeper of reproduction and is essential for the initiation of human puberty and maintenance of adult reproduction. Kisspeptin neurons appear to be integrative sensors, as they respond to changes in numerous internal and external factors including nutrient and fat status, stress and sex steroids, thus providing a link between these factors and reproduction. We have pioneered the development of kisspeptin antagonists as powerful tools for interrogating the role of kisspeptin in reproductive physiology and pathology, and as potential treatments for hormone-dependent disease. This article summarizes their development and key findings to date. These demonstrate an essential role for kisspeptin in GnRH neuron firing, GnRH pulsatile secretion, negative feedback by gonadal steroids, the onset of puberty, and the ovulatory LH surge. These studies establish that kisspeptin antagonists are powerful investigative tools and set the scene for more extensive physiological and pathophysiological studies as well as therapeutic intervention.