Potential role of follicle-stimulating hormone (FSH) and transforming growth factor (TGFβ1) in the regulation of ovarian angiogenesis.
ABSTRACT Angiogenesis occurs during ovarian follicle development and luteinization. Pituitary secreted FSH was reported to stimulate the expression of endothelial mitogen VEGF in granulosa cells. And, intraovarian cytokine transforming growth factor (TGF)β1 is known to facilitate FSH-induced differentiation of ovarian granulosa cells. This intrigues us to investigate the potential role of FSH and TGFβ1 regulation of granulosa cell function in relation to ovarian angiogenesis. Granulosa cells were isolated from gonadotropin-primed immature rats and treated once with FSH and/or TGFβ1 for 48 h, and the angiogenic potential of conditioned media (granulosa cell culture conditioned media; GCCM) was determined using an in vitro assay with aortic ring embedded in collagen gel and immunoblotting. FSH and TGFβ1 increased the secreted angiogenic activity in granulosa cells (FSH + TGFβ1 > FSH ≈ TGFβ1 >control) that was partly attributed to the increased secretion of pro-angiogenic factors VEGF and PDGF-B. This is further supported by the evidence that pre-treatment with inhibitor of VEGF receptor-2 (Ki8751) or PDGF receptor (AG1296) throughout or only during the first 2-day aortic ring culture period suppressed microvessel growth in GCCM-treated groups, and also inhibited the FSH + TGFβ1-GCCM-stimulated release of matrix remodeling-associated gelatinase activities. Interestingly, pre-treatment of AG1296 at late stage suppressed GCCM-induced microvessel growth and stability with demise of endothelial and mural cells. Together, we provide original findings that both FSH and TGFβ1 increased the secretion of VEGF and PDGF-B, and that in turn up-regulated the angiogenic activity in rat ovarian granulosa cells. This implicates that FSH and TGFβ1 play important roles in regulation of ovarian angiogenesis during follicle development.
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ABSTRACT: Cytokines are key regulators of ovarian physiology, particularly in relation to folliculogenesis and ovulation, where they contribute to creating an environment supporting follicle selection and growth. Their manifold functions include regulating cellular proliferation/differentiation, follicular survival/atresia, and oocyte maturation. Several cytokines, such as TGFβ-superfamily members, are involved at all stages of folliculogenesis while the production of others is stage-dependent. This review draws upon evidence from both human and animal models to highlight the species-specific roles at each milestone of follicular developmental. Given these pivotal roles and their ease of detection in follicular fluid, cytokines have been considered as attractive biomarkers of oocyte maturational status and of successful assisted reproductive outcome. Despite this, our understanding of cytokines and their interactions remains incomplete, and is still frequently limited to overly simplistic descriptions of their interrelationships. Given our increased appreciation of cytokine activity in complex and highly regulated networks, we put forward the case for using Bayesian modelling approaches to describe their hierarchical relationships in order to predict causal physiological interactions in vivo. Mol. Reprod. Dev. © 2013 Wiley Periodicals, Inc.Molecular Reproduction and Development 11/2013; · 2.81 Impact Factor
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ABSTRACT: Mathematical models of the hypothalamus-pituitary-ovarian axis in women were first developed by Schlosser and Selgrade in 1999, with subsequent models of Harris-Clark et al. (Bull. Math. Biol. 65(1):157-173, 2003) and Pasteur and Selgrade (Understanding the dynamics of biological systems: lessons learned from integrative systems biology, Springer, London, pp. 38-58, 2011). These models produce periodic in-silico representation of luteinizing hormone (LH), follicle stimulating hormone (FSH), estradiol (E2), progesterone (P4), inhibin A (InhA), and inhibin B (InhB). Polycystic ovarian syndrome (PCOS), a leading cause of cycle irregularities, is seen as primarily a hyper-androgenic disorder. Therefore, including androgens into the model is necessary to produce simulations relevant to women with PCOS. Because testosterone (T) is the dominant female androgen, we focus our efforts on modeling pituitary feedback and inter-ovarian follicular growth properties as functions of circulating total T levels. Optimized parameters simultaneously simulate LH, FSH, E2, P4, InhA, and InhB levels of Welt et al. (J. Clin. Endocrinol. Metab. 84(1):105-111, 1999) and total T levels of Sinha-Hikim et al. (J. Clin. Endocrinol. Metab. 83(4):1312-1318, 1998). The resulting model is a system of 16 ordinary differential equations, with at least one stable periodic solution. Maciel et al. (J. Clin. Endocrinol. Metab. 89(11):5321-5327, 2004) hypothesized that retarded early follicle growth resulting in "stockpiling" of preantral follicles contributes to PCOS etiology. We present our investigations of this hypothesis and show that varying a follicular growth parameter produces preantral stockpiling and a period-doubling cascade resulting in apparent chaotic menstrual cycle behavior. The new model may allow investigators to study possible interventions returning acyclic patients to regular cycles and guide developments of individualized treatments for PCOS patients.Bulletin of Mathematical Biology 11/2013; · 2.02 Impact Factor
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ABSTRACT: Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) may play important roles in prostate cancer (PCa) progression. Specifically, LH expression in PCa tissues has been associated with metastatic disease with a poor prognosis, while FSH has been shown to stimulate prostate cell growth in hormone-refractory PCa cell lines. Gonadotropin-realizing hormone (GnRH) analogues are common agents used for achieving androgen deprivation in the treatment for PCa. GnRH analogues include LH-releasing hormone (LHRH) agonists and GnRH antagonists, both of which exhibit distinct mechanisms of action that may be crucial in terms of their overall clinical efficacy. LHRH agonists are typically used as the primary therapy for most patients and function via a negative-feedback mechanism. This mechanism involves an initial surge in testosterone levels, which may worsen clinical symptoms of PCa. GnRH antagonists provide rapid and consistent hormonal suppression without the initial surge in testosterone levels associated with LHRH agonists, thus representing an important therapeutic alternative for patients with PCa. The concentrations of testosterone and dihydrotestosterone are significantly reduced after treatment with both LHRH agonists and GnRH antagonists. This reduction in testosterone concentrations to castrate levels results in significant, rapid, and consistent reductions in prostatic-specific antigen, a key biomarker for PCa. Evidence suggests that careful maintenance of testosterone levels during androgen deprivation therapy provides a clinical benefit to patients with PCa, emphasizing the need for constant monitoring of testosterone concentrations throughout the course of therapy.World Journal of Urology 09/2013; · 2.89 Impact Factor