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Shilo M, Mayo A, Alon U. A Mechanism for Ovulation Number Control. Front Endocrinol (Lausanne) 2022; 13:816967. [PMID: 35909517 PMCID: PMC9329923 DOI: 10.3389/fendo.2022.816967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 05/26/2022] [Indexed: 11/29/2022] Open
Abstract
Every menstrual cycle, many follicles begin to develop but only a specific number ovulate. This ovulation number determines how many offspring are produced per litter, and differs between species. The physiological mechanism that controls ovulation number is unknown; a class of mathematical models can explain it, but these models have no physiological basis. Here, we suggest a physiological mechanism for ovulation number control, which enables selection of a specific number of follicles out of many, and analyze it in a mathematical model of follicular growth. The mechanism is based on a signal, intra-follicular androgen concentration, that measures follicle size relative to the other follicles. This signal has a biphasic effect, suppressing follicles that are too large or too small compared to others. The ovulation number is determined by the androgen inhibitory thresholds. The model has a scaling symmetry that explains why the dominant follicles grow linearly with time, as observed in human ultrasound data. This approach also explains how chronic hyperandrogenism disrupts ovulation in polycystic ovary syndrome (PCOS), a leading cause of infertility. We propose specific experiments for testing the proposed mechanism.
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Affiliation(s)
| | | | - Uri Alon
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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2
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Fischer-Holzhausen S, Röblitz S. Hormonal regulation of ovarian follicle growth in humans: Model-based exploration of cycle variability and parameter sensitivities. J Theor Biol 2022; 547:111150. [PMID: 35568223 DOI: 10.1016/j.jtbi.2022.111150] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 03/23/2022] [Accepted: 04/28/2022] [Indexed: 10/18/2022]
Abstract
We present a modelling and simulation framework for the dynamics of ovarian follicles and key hormones along the hypothalamic-pituitary-gonadal axis throughout consecutive human menstrual cycles. All simulation results (hormone concentrations and ovarian follicle sizes) are in biological units and can easily be compared to clinical data. The model takes into account variability in follicles' response to stimulating hormones, which introduces variability between cycles. The growth of ovarian follicles in waves is an emergent property in our model simulations and further supports the hypothesis that follicular waves are also present in humans. We use Approximate Bayesian Computation and cluster analysis to construct a population of virtual subjects and to study parameter distributions and sensitivities. The model can be used to compare and optimize treatment protocols for ovarian hyperstimulation, thus potentially forming the integral part of a clinical decision support system in reproductive endocrinology.
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Affiliation(s)
| | - Susanna Röblitz
- Computational Biology Unit, Department of Informatics, University of Bergen, Bergen, Norway
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Jarrett BY, Vanden Brink H, Oldfield AL, Lujan ME. Ultrasound Characterization of Disordered Antral Follicle Development in Women with Polycystic Ovary Syndrome. J Clin Endocrinol Metab 2020; 105:5891761. [PMID: 32785651 PMCID: PMC7473602 DOI: 10.1210/clinem/dgaa515] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 08/06/2020] [Indexed: 01/26/2023]
Abstract
CONTEXT The mechanism of oligo-anovulation in polycystic ovary syndrome (PCOS) is unknown. OBJECTIVES To evaluate follicular and endocrine characteristics of anovulatory and sporadic ovulatory cycles in women with PCOS. DESIGN Prospective, longitudinal study. SETTING Academic clinical research unit. PARTICIPANTS 26 reproductive-aged women (18-38 years) with PCOS, observed during natural anovulatory (PCOS-Anov; n = 12) and sporadic ovulatory cycles (PCOS-Ov; n = 14), and 12 controls. INTERVENTIONS Transvaginal ultrasonography and venipuncture were performed every other day for 4 to 6 weeks in women with PCOS or at 1 interovulatory interval in control subjects. MAIN OUTCOME MEASURES Follicle number and diameter (ie, ≥2 mm) were quantified at each visit. Individual growth profiles were assessed for all follicles that grew to ≥7 mm. Blood samples were assayed for follicle-stimulating hormone, luteinizing hormone, estradiol, and progesterone. RESULTS Follicular excess, or heightened follicle number versus controls, was observed across anovulatory and sporadic ovulatory cycles in PCOS. In PCOS-Anov, follicles emerged cyclically in some women (6/12; 50%) and continuously in others (6/12; 50%), then grew to a mean maximum diameter of 7.2 mm and regressed within 4.7 days. In PCOS-Ov, follicles mostly emerged cyclically as part of a cohort and dominant follicles showed normal growth to ovulation-albeit mean and maximum luteal progesterone concentrations were significantly lower versus controls. CONCLUSIONS Follicle growth and regression were detected on ultrasonography amidst perpetual follicular excess in PCOS. Documentation of continuous follicle recruitment and turnover, the absence of persistence, and altered luteal progesterone following sporadic ovulation, provide formative data on antral follicle development in PCOS.
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Affiliation(s)
| | | | - Alexis L Oldfield
- Division of Nutritional Sciences, Cornell University, Ithaca, New York
| | - Marla E Lujan
- Division of Nutritional Sciences, Cornell University, Ithaca, New York
- Correspondence and Reprint Requests: Marla E. Lujan, PhD, Associate Professor, Division of Nutritional Sciences, Cornell University, 216 Savage Hall, Ithaca, NY 14853, USA. E-mail:
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4
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Characterization of circular RNA expression profiles in cumulus cells from patients with polycystic ovary syndrome. Fertil Steril 2019; 111:1243-1251.e1. [PMID: 30979425 DOI: 10.1016/j.fertnstert.2019.02.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/23/2019] [Accepted: 02/17/2019] [Indexed: 01/24/2023]
Abstract
OBJECTIVE To determine aberrant circular RNA (circRNA) expression profiles in cumulus cells from polycystic ovarian syndrome (PCOS) patients and identify their potential biological functions. DESIGN Circular RNAs microarray analysis of human tissue. SETTING University hospital. PATIENT(S) A total of 40 women, including 20 PCOS patients and 20 non-PCOS patients. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) A circRNA microarray containing probes that interrogate 21,442 human circRNAs to investigate differentially expressed circRNAs in cumulus cells, with potential target genes of significantly changed circRNAs and biological functions measured by microRNA support vector regression (mirSVR) and gene ontology (GO) analysis, with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. RESULT(S) A total of 1,032 circRNAs were identified that were differentially expressed in PCOS cumulus cells, including 311 circRNAs increase and 721 circRNAs decrease (fold change ≥2). Four aberrantly expressed circRNAs reached a statistically significant result after Bonferroni correction (with Bonferroni correction, only circRNAs for which P < .05/21,442 = 2.3 × 10-6 were considered statistically significant). Further analysis showed that aberrantly expressed circRNAs harbored microRNA binding sites, and some microRNAs were associated with PCOS. The GO and KEGG biological pathway analysis indicated that the genes with protein binding, mitotic nuclear envelope disassembly and metabolic pathways were statistically significantly enriched. CONCLUSION(S) Our data suggest that the aberrantly expressed circRNAs and their targeted genes might be associated with PCOS, providing new clues to find key diagnostic and therapeutic molecular biomarkers for PCOS patients.
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Lange A, Schwieger R, Plöntzke J, Schäfer S, Röblitz S. Follicular competition in cows: the selection of dominant follicles as a synergistic effect. J Math Biol 2018; 78:579-606. [PMID: 30194480 DOI: 10.1007/s00285-018-1284-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/04/2018] [Indexed: 11/29/2022]
Abstract
The reproductive cycle of mono-ovulatory species such as cows or humans is known to show two or more waves of follicular growth and decline between two successive ovulations. Within each wave, there is one dominant follicle escorted by subordinate follicles of varying number. Under the surge of the luteinizing hormone a growing dominant follicle ovulates. Rarely the number of ovulating follicles exceeds one. In the biological literature, the change of hormonal concentrations and individually varying numbers of follicular receptors are made responsible for the selection of exactly one dominant follicle, yet a clear cause has not been identified. In this paper, we suggest a synergistic explanation based on competition, formulated by a parsimoniously defined system of ordinary differential equations (ODEs) that quantifies the time evolution of multiple follicles and their competitive interaction during one wave. Not discriminating between follicles, growth and decline are given by fixed rates. Competition is introduced via a growth-suppressing term, equally supported by all follicles. We prove that the number of dominant follicles is determined exclusively by the ratio of follicular growth and competition. This number turns out to be independent of the number of subordinate follicles. The asymptotic behavior of the corresponding dynamical system is investigated rigorously, where we demonstrate that the [Formula: see text]-limit set only contains fixed points. When also including follicular decline, our ODEs perfectly resemble ultrasound data of bovine follicles. Implications for the involved but not explicitly modeled hormones are discussed.
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Affiliation(s)
- Alexander Lange
- Computational Systems Biology, Zuse Institute Berlin, Berlin, Germany. .,Department of Applied Biosciences and Process Engineering, Anhalt University of Applied Sciences, Köthen, Germany.
| | - Robert Schwieger
- Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany
| | - Julia Plöntzke
- Computational Systems Biology, Zuse Institute Berlin, Berlin, Germany
| | - Stefan Schäfer
- Computational Systems Biology, Zuse Institute Berlin, Berlin, Germany
| | - Susanna Röblitz
- Computational Systems Biology, Zuse Institute Berlin, Berlin, Germany.,Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany
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6
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Zhang J, Liu J, Zhu K, Hong Y, Sun Y, Zhao X, Du Y, Chen ZJ. Effects of BMAL1-SIRT1-positive cycle on estrogen synthesis in human ovarian granulosa cells: an implicative role of BMAL1 in PCOS. Endocrine 2016; 53:574-84. [PMID: 27117143 DOI: 10.1007/s12020-016-0961-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 04/14/2016] [Indexed: 01/24/2023]
Abstract
Brain and muscle ARNT-like protein 1 (BMAL1) is necessary for fertility and has been found to be essential to follicle growth and steroidogenesis. Sirtuin1 (SIRT1) has been reported to interact with BMAL1 and function in a circadian manner. Evidence has shown that SIRT1 regulates aromatase expression in estrogen-producing cells. We aimed to ascertain if there is a relationship between polycystic ovary syndrome (PCOS) and BMAL1, and whether and how BMAL1 takes part in estrogen synthesis in human granulosa cells (hGCs). Twenty-four women diagnosed with PCOS and 24 healthy individuals undergoing assisted reproduction were studied. BMAL1 expression in their granulosa cells (GCs) was observed by quantitative real-time polymerase chain reaction (qRT-PCR). The level of expression in the PCOS group was lower than that of the group without PCOS (p < 0.05). We also analyzed estrogen synthesis and aromatase expression in KGN cell lines. Both were downregulated after BMAL1 and SIRT1 knock-down and, conversely, upregulated after overexpression treatments of these two genes in KGN cells. Both BMAL1 and SIRT1 had a mutually positive regulation, as did the phosphorylation of JNK. Furthermore, JNK overexpression increased estrogen synthesis activity and the expression levels of aromatase, BMAL1, and SIRT1. In KGN and hGCs, estrogen synthesis and aromatase expression were downregulated after treatment with JNK and SIRT1 inhibitors. In addition, BMAL1, SIRT1, and JNK expression levels were all downregulated. Our results demonstrate the effects of BMAL1 on estrogen synthesis in hGCs and suggest a BMAL1-SIRT1-JNK positive feedback cycle in this process, which points out an important role of BMAL1 in the development of PCOS.
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Affiliation(s)
- Jiaou Zhang
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 845 Lingshan Road, Shanghai, 200135, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China
| | - Jiansheng Liu
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 845 Lingshan Road, Shanghai, 200135, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China
| | - Kai Zhu
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 845 Lingshan Road, Shanghai, 200135, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China
| | - Yan Hong
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 845 Lingshan Road, Shanghai, 200135, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China
| | - Yun Sun
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 845 Lingshan Road, Shanghai, 200135, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China
| | - Xiaoming Zhao
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 845 Lingshan Road, Shanghai, 200135, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China
| | - Yanzhi Du
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 845 Lingshan Road, Shanghai, 200135, China.
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China.
| | - Zi-Jiang Chen
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 845 Lingshan Road, Shanghai, 200135, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, The Key Laboratory for Reproductive Endocrinology of Ministry of Education, Shandong Provincial Key Laboratory of Reproductive Medicine, Center for Reproductive Medicine, Shandong Provincial Hospital, Shandong University, Jingwu Road 324, Jinan, 250021, China
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7
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Abstract
Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women. The syndrome is typified by its heterogeneous presentation, which includes hirsutism (a function of hypersecretion of ovarian androgens), menstrual irregularity and infertility (that is due to infrequent or absent ovulation). Furthermore, PCOS predisposes patients to metabolic dysfunction and an increased risk of type 2 diabetes mellitus (T2DM). The aetiology of the syndrome has a major genetic component. Obesity exacerbates the insulin resistance that is a feature of PCOS in many women and amplifies the clinical and biochemical abnormalities. In clinical practice, the choice of investigations to be done depends mainly on the presenting symptoms. The approach to management is likewise dependent on the presenting complaint. Symptoms of androgen excess (hirsutism, acne and alopecia) require cosmetic measures, suppression of ovarian androgen function and anti-androgen therapy, alone or in combination. Ovulation rate is improved by diet and lifestyle intervention in overweight individuals but induction of ovulation by, in the first instance, anti-estrogens is usually required. Monitoring of glucose is important in overweight women and/or those with a family history of T2DM. Metformin is indicated for women with impaired glucose tolerance but whether this drug is otherwise useful in women with PCOS remains debatable.
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Affiliation(s)
- Channa N Jayasena
- Section of Investigative Medicine, Imperial College London, Hammersmith Hospital, DuCane Road, London W12 0NN, UK
| | - Stephen Franks
- Institute of Reproductive and Developmental Biology, Imperial College London, Hammersmith Hospital, DuCane Road, London W12 0NN, UK
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A mathematical model of the bovine oestrous cycle: simulating outcomes of dietary and pharmacological interventions. J Theor Biol 2012; 313:115-26. [PMID: 22925571 DOI: 10.1016/j.jtbi.2012.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 05/16/2012] [Accepted: 08/08/2012] [Indexed: 11/20/2022]
Abstract
A mathematical model was constructed to simulate the bovine oestrous cycle by using nonlinear differential equations to describe the biological mechanisms which regulate the cycle. The model predicts circulating concentrations of gonadotrophin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, oestradiol, inhibin and progesterone. These hormones collectively provide control and feedback mechanisms between the hypothalamus, pituitary gland and ovaries, which regulate ovarian follicular dynamics, corpus luteum function and ovulation. When follicular growth parameters are altered, the model predicts that cows will exhibit either two or three follicular waves per cycle, as seen in practice. Changes in other parameters allow the model to simulate: effects of nutrition on follicle recruitment and size of the ovulatory follicle; effects of negative energy balance on postpartum anoestrus; and effects of pharmacological intervention on hormone profiles and timing of ovulation. It is concluded that this model provides a sound basis for exploring factors that influence the bovine oestrous cycle in order to test hypotheses about nutritional and hormonal influences which, with further validation, should help to design dietary or pharmacological strategies for improving reproductive performance in cattle.
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9
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Imbar T, Klipper E, Greenfield C, Hurwitz A, Haimov-Kochman R, Meidan R. Altered endothelin expression in granulosa-lutein cells of women with polycystic ovary syndrome. Life Sci 2012; 91:703-9. [PMID: 22727793 DOI: 10.1016/j.lfs.2012.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 05/08/2012] [Accepted: 06/01/2012] [Indexed: 11/25/2022]
Abstract
AIMS To examine the levels of endothelin system components in granulosa lutein cells (GLCs) of women with PCOS and compare them to normally ovulating women undergoing In Vitro Fertilization (IVF). Polycystic ovary syndrome (PCOS) is one of the most common endocrine-metabolic disorders in women of reproductive age. Endothelins are locally produced by endothelial and granulosa cells of the preovulatory follicle. Abnormal expression or production of endothelins may be a contributing factor in PCOS pathogenesis. MAIN METHODS Follicular aspirates containing GLCs were obtained from PCOS and normally ovulating patients undergoing oocyte retrieval during the IVF cycle. RNA was extracted and endothelin system components were quantified using real-time PCR. GLCs were cultured in basal media for 7 days, and then challenged with various luteinizing agents (luteinizing hormone, hCG, or forskolin) for 24 h. KEY FINDINGS In GLCs from women with PCOS, Endothelin-1 mRNA expression was elevated (2.2-fold) as compared with normally ovulating women, whereas endothelin-2 mRNA was reduced (1.8-fold). ET receptors and endothelin-converting enzyme showed the same expression levels in the two groups. In vitro modeling showed that although the steroidogenic response was preserved in GLC, endothelin expression levels were not exhibited in vitro in their original pattern. SIGNIFICANCE Dysregulation of ovarian endothelin expression may induce a pathologic ovulation pattern characteristic of PCOS.
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Affiliation(s)
- Tal Imbar
- IVF Unit, Department of Obstetrics & Gynecology, Hadassah Hebrew University Medical Center, Mt. Scopus, Jerusalem, Israel.
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10
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Androgens and poor responders: are we ready to take the plunge into clinical therapy? Fertil Steril 2011; 96:1062-5. [PMID: 22036049 DOI: 10.1016/j.fertnstert.2011.09.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 09/28/2011] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To review and summarize data from the scientific literature on the use of androgens to improve ovarian function. DESIGN Review of pertinent literature. SETTING University hospital. PATIENT(S) Women exposed to androgens. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Critical review of the literature. RESULT(S) The artificial increase of intra-ovarian androgen concentrations constitutes an attractive concept for improving the deficient ovarian function of poor responders. Data from studies conducted in animals treated with high-dose androgens, together with observations made in hyperandrogenic women or female-to-male transsexuals receiving virilizing androgen doses, indicate that androgens may increase follicle responsiveness to FSH and/or the number of growing follicles in the ovary. Yet, definite clinical demonstration of such a concept still is not available. CONCLUSION(S) Current clinical approaches aiming at increasing androgen availability in the ovary showed conflicting results. Therefore, additional studies using proper strategies to achieving higher intra-ovarian androgen concentrations for longer intervals are required to define the clinical efficiency of androgens in poor responders.
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11
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Lyles D, Tien JH, McCobb DP, Zeeman ML. Pituitary network connectivity as a mechanism for the luteinising hormone surge. J Neuroendocrinol 2010; 22:1267-78. [PMID: 20961340 DOI: 10.1111/j.1365-2826.2010.02084.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ovulation in vertebrates is caused by a surge of luteinising hormone (LH) from the pituitary. The LH surge is initiated by rising oestradiol concentration, although the precise mechanism of oestradiol action in humans and primates is not yet understood. Recent advances in labelling and three-dimensional imaging have revealed a rich pituitary structure of interwoven networks of different cell types. In the present study, we develop a mathematical model to test the hypothesis that oestradiol modulation of connectivity between pituitary cells can underlie the LH surge. In the model, gonadotrophin-releasing hormone (GnRH) pulses stimulate LH secretion by two independent mechanisms. The first mechanism corresponds to the well known direct action of GnRH on gonadotrophs, which is inhibited by the rising oestradiol concentration. The second mechanism of GnRH action is to stimulate a recurrent network of pituitary cells; in this case, the folliculostellate cells, which in turn stimulate LH secretion from the gonadotrophs. The network activity is modelled by a one-dimensional ordinary differential equation. The key to the LH surge in the model lies in the assumption that oestradiol modulates network connectivity. When the circulating oestradiol concentration is low, the network is barely connected, and cannot maintain a recurrent signal. When the oestradiol concentration is high, the network is highly connected, and maintains a high level of activity even after GnRH stimulation, thereby leading to a surge of LH secretion.
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Affiliation(s)
- D Lyles
- Department of Environmental Science and Policy, UC Davis, Davis, CA, USA
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12
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Moran LJ, Noakes M, Clifton PM, Norman RJ. The use of anti-mullerian hormone in predicting menstrual response after weight loss in overweight women with polycystic ovary syndrome. J Clin Endocrinol Metab 2007; 92:3796-802. [PMID: 17652213 DOI: 10.1210/jc.2007-1188] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND Polycystic ovary syndrome (PCOS) is associated with reproductive and metabolic abnormalities, specifically menstrual dysfunction and anovulation in conjunction with elevated pre-antral follicle number and arrested follicular maturation. Although anti-müllerian hormone (AMH), an inhibitor of follicle recruitment and maturation, is increased in women with PCOS, the usefulness of circulating AMH levels as a clinical predictor of menstrual response to weight loss in PCOS is not known. METHODS Overweight women with PCOS (n = 26, age 32.9 +/- 5.8 yr, weight 98.9 +/- 20.8 kg, body mass index 36.1 +/- 7.0 kg/m(2), mean +/- sd) followed an 8-wk weight loss and 6-month weight maintenance program. RESULTS Net reductions in weight (4.6 +/- 4.8 kg), waist circumference (6.0 +/- 5.3 cm), testosterone (0.3 +/- 0.6 nmol/liter), fasting insulin (3.7 +/- 7.6 mU/liter), and the homeostasis model assessment of insulin sensitivity (0.7 +/- 1.3) occurred for all subjects over the entire study duration. Of 26 subjects, 15 (57.7%) responded to the intervention with improvements in menstrual cyclicity (responders). Compared to nonresponders, responders had lower AMH levels at baseline (23.6 +/- 12.0 vs. 37.9 +/- 17.8 pmol/liter; P = 0.021). Only responders had reductions in fasting insulin (6.1 +/- 5.9 mU/liter; P = 0.001) and homeostasis model assessment (1.3 +/- 5.9; P = 0.002) with acute weight loss (wk 0-8). Baseline AMH was most strongly predicted by baseline ghrelin, free testosterone, and insulin (r(2) = 0.528; P = 0.002). CONCLUSIONS Overweight women with PCOS who respond to weight loss with menstrual improvements have significantly reduced preweight loss AMH and demonstrate improvements in surrogate measures of insulin resistance with weight loss. Pretreatment AMH is a potential clinical predictor of menstrual improvements with weight loss in PCOS.
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Affiliation(s)
- Lisa J Moran
- Research Centre for Reproductive Health, Discipline of Obstetrics and Gynaecology, University of Adelaide, 6th Floor, Medical School North, Adelaide SA 5005, Australia
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13
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Reinecke I, Deuflhard P. A complex mathematical model of the human menstrual cycle. J Theor Biol 2007; 247:303-30. [PMID: 17448501 DOI: 10.1016/j.jtbi.2007.03.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Revised: 03/08/2007] [Accepted: 03/08/2007] [Indexed: 10/23/2022]
Abstract
Despite the fact that more than 100 million women worldwide use birth control pills and that half of the world's population is concerned, the menstrual cycle has so far received comparatively little attention in the field of mathematical modeling. The term menstrual cycle comprises the processes of the control system in the female body that, under healthy circumstances, lead to ovulation at regular intervals, thus making reproduction possible. If this is not the case or ovulation is not desired, the question arises how this control system can be influenced, for example, by hormonal treatments. In order to be able to cover a vast range of external manipulations, the mathematical model must comprise the main components where the processes belonging to the menstrual cycle occur, as well as their interrelations. A system of differential equations serves as the mathematical model, describing the dynamics of hormones, enzymes, receptors, and follicular phases. Since the processes take place in different parts of the body and influence each other with a certain delay, passing over to delay differential equations is deemed a reasonable step. The pulsatile release of the gonadotropin-releasing hormone (GnRH) is controlled by a complex neural network. We choose to model the pulse time points of this GnRH pulse generator by a stochastic process. Focus in this paper is on the model development. This rather elaborate mathematical model is the basis for a detailed analysis and could be helpful for possible drug design.
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Affiliation(s)
- Isabel Reinecke
- Zuse Institute Berlin, Department of Numerical Analysis and Modelling, Research Group Computational Drug Design, Takustrasse 7, 14195 Berlin, Germany.
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14
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Webber LJ, Stubbs SA, Stark J, Margara RA, Trew GH, Lavery SA, Hardy K, Franks S. Prolonged survival in culture of preantral follicles from polycystic ovaries. J Clin Endocrinol Metab 2007; 92:1975-8. [PMID: 17341570 DOI: 10.1210/jc.2006-1422] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT In polycystic ovary syndrome (PCOS), an increased proportion of follicles leave the primordial (resting) pool and initiate growth. However, there is little evidence for a reduced reproductive life span (early menopause) in women with PCOS, suggesting that the dynamics of follicle growth, and of follicle loss by atresia, is altered in PCOS. OBJECTIVE The aim of this study was to investigate the possibility that loss of preantral follicles by atresia is reduced in PCOS, leading to prolonged follicle survival. DESIGN We compared follicle growth in normal and polycystic ovaries using cultures of small ovarian biopsies. SETTING Tissue samples were obtained at routine laparoscopy from 12 patients with anovulatory PCOS and 16 controls and processed in an ovarian physiology laboratory. MAIN OUTCOME MEASURES We performed morphometric analysis of follicle population in tissue fixed at time of biopsy (d 0) or after 5, 10, or 15 d in culture. Analyses included assessment of follicle and oocyte diameter, number and proportion of primordial and growing follicles, and number and proportion of atretic follicles. RESULTS In tissue fixed on d 0, the proportion of healthy growing follicles was, as expected, greater in ovaries from PCOS patients than in normal ovaries (64 vs. 28%; P = 0.0005), but there were no differences between PCOS and normal tissue during culture. The rate of atresia throughout the period of culture in follicles was, however, significantly lower in PCOS tissue (P < 0.0001). After culture, 80% of follicles in normal ovarian tissue were atretic compared with 53% in PCOS biopsies. CONCLUSION Follicles from polycystic ovaries demonstrate a decreased rate of atresia in culture, suggesting a mechanism for maintaining a larger follicle pool throughout reproductive life.
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Affiliation(s)
- Lisa J Webber
- Imperial College School of Medicine, Institute of Reproductive and Developmental Biology, Hammersmith Hospital, Du Cane Road, London W12 0NN, United Kingdom
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Sarty GE, Pierson RA. An application of Lacker’s mathematical model for the prediction of ovarian response to superstimulation. Math Biosci 2005; 198:80-96. [PMID: 16185721 DOI: 10.1016/j.mbs.2005.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Revised: 06/15/2005] [Accepted: 07/20/2005] [Indexed: 10/25/2022]
Abstract
Introduction. A mathematical model of ovarian follicular growth is applied to the problem of predicting ovarian response in a superstimulation protocol. Methods. Fifty-four women enrolled in an ovarian superstimulation program of therapy for the amelioration of idiopathic infertility had their ovarian cycles synchronized by taking Demulen 30 for two weeks prior to the study. Daily ultrasonographic imaging, measurements of serum estradiol and doses of hMG began on day 5 after the patients stopped taking Demulen. The diameters of individual follicles were measured and followed daily. When the largest follicle attained a diameter of 19 mm, hCG was given to induce ovulation. Individual follicle growth data were fit to a mathematical model of ovarian follicle maturation and the resulting parameters were used to classify patients into low and high ovarian response groups. Results. The parameters computed from the mathematical model fit were found to be predictive of ovarian response with a sensitivity of 71% and a specificity of 70%. The parameters were also meaningful within the context of the original mathematical model and have value for determining how doses of hMG may be adjusted during the course therapy to increase the ovarian response in individuals. Conclusion. Mathematical modeling of ultrasonographically derived follicular growth data has significant potential for clinical application in ovarian superstimulation protocols. The method of fitting follicular growth data to a mathematical follicle maturation surface furthermore provides a straightforward approach for the characterization of ovarian follicular dynamics in general.
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Affiliation(s)
- Gordon E Sarty
- Department of Psychology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5A5.
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16
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Echenim N, Monniaux D, Sorine M, Clément F. Multi-scale modeling of the follicle selection process in the ovary. Math Biosci 2005; 198:57-79. [PMID: 16038949 DOI: 10.1016/j.mbs.2005.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 04/29/2005] [Accepted: 05/15/2005] [Indexed: 10/25/2022]
Abstract
The biological meaning of follicular development is to free fertilizable oocytes at the time of ovulation. The ovulation rate results from an FSH-dependent follicle selection process. In this paper, we designed a multi-scale model of follicular development, where selection arises from the endocrine feedback between the ovaries and pituitary gland and appeals to control theory concepts. Each ovarian follicle is described through a 2D density function giving an age and maturity-structured description of its cell population. The control intervenes in the velocity, gain and loss terms of the conservation law ruling the changes in the density. The model accounts for the changes in the total cell number, growth fraction and global maturity of both ovulatory and degenerating follicles for various intensities of the selection rate. The different selection process outputs (mono- or poly-ovulation, anovulation) predicted by the model are consistent with physiological knowledge regarding vascularization, pituitary sensitivity to ovarian feedback and treatment with exogenous FSH.
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Affiliation(s)
- Nki Echenim
- Unité de Recherche INRIA Rocquencourt, Domaine de Voluceau, Rocquencourt BP 105, 78153 Le Chesnay Cedex, France
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17
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Abstract
The analytical representation and simulation of complex molecular pathways can contribute to understanding and evaluating physiological as well as pathological processes. We are interested in modeling the processes of menopause to stratify women in terms of the genotypic and environmental components and their implications for development of individualized risk of postmenopausal disorders, e.g., breast and ovarian cancer, cardiovascular disease, and osteoporosis. We have initiated this study using the UltraSAN package to analyze the pathway associated with estrogen production. This model incorporates detailed information about the hormone factors affecting estrogen production, and the simulations carried out are based on published experimental data corresponding to hormone levels during the course of the normal female reproductive cycle. The agreement between the experimental data and the simulation is typically less than 2 ng/ml or 2 pg/ml respectively for progesterone and estradiol output. This approach further permits inclusion of information about an SNP observed in the gene coding for the enzyme aromatase as a model to study the impact of reduced enzymatic activity on hormone levels.
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Affiliation(s)
- Dimitra Tsavachidou
- Affiliations of the authors: Abramson Family Cancer Research Institute, University of Pennsylvania Cancer Center, Philadelphia, Pennsylvania
| | - Michael N. Liebman
- Affiliations of the authors: Abramson Family Cancer Research Institute, University of Pennsylvania Cancer Center, Philadelphia, Pennsylvania
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18
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Edelstein-Keshet L, Israel A, Lansdorp P. Modelling perspectives on aging: can mathematics help us stay young? J Theor Biol 2001; 213:509-25. [PMID: 11742522 DOI: 10.1006/jtbi.2001.2429] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We survey several types of mathematical models that keep track of age distributions in a population, or follow some aspects of aging, such as loss of replicative potential of stem cells. The properties of a class of linear models of this type are discussed and compared. We illustrate the applicability of such models with a simple example based on hypothetical stem cell dynamics developed to address age-related telomere loss in the human granulocyte pool. We then describe the contrasting behaviour of nonlinear systems. Examples are drawn from the class of "dynamical diseases" to illustrate some of the aspects of nonlinear systems. Applications of these, and other models to the problems of aging and replicative aging are discussed.
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19
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Abstract
The offspring of older parents are at a higher risk of suffering low birth weights and congenital birth defects that result from mutations and chromosomal anomalies. When the defect is paternal in origin, it often can be shown that the primary lesion arose during mitotic proliferation of the spermatogonial germ cell population. By contrast, germline mosaicism is seldom invoked to explain the age dependency of maternally derived aberrations because germline proliferation in the ovary is already completed during fetal development. Age-dependent defects of maternal origin might, however, be explained in part by the progressive loss of oocytes during the mother's reproductive life. A large number of oocytes undergo the initial stages of maturation each month, but typically only one completes maturation and is ovulated while the majority are discarded, probably by an apoptotic mechanism. Here we explore the possibility that the monthly choice of oocytes to undergo maturation is influenced by subtle phenotypic characters of those oocytes that may bear genetic defects such as trisomy 21. We have generated a mathematical model to describe the loss kinetics for such mutant oocytes relative to the overall pool of resting oocytes, and we assess evolutionary strategies that would favor their utilization faster than, at the same rate as, or slower than the normal oocytes. This formulation reveals that the slower-rate scheme would effectively diminish the utilization of mutant oocytes in young mothers but would increase the risk of related birth defects for older mothers. Accordingly, we propose that natural selection should have favored the delayed utilization of defective oocytes in a primitive high-mortality culture, but that this evolutionary strategy would be outmoded for modern society, because it would lead to an increased frequency of birth defects for older mothers.
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Affiliation(s)
- C J Zheng
- Division of Environmental and Occupational Health, University of Minnesota, Minneapolis 55455, USA.
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20
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Abstract
Anovulation in women with polycystic ovary syndrome (PCOS) is characterised by arrested growth of antral follicles. A relative lack of FSH may contribute to the persistence of anovulation but is unlikely, by itself, to be a major cause of it. Granulosa cells from anovulatory women with polycystic ovaries hypersecrete oestradiol, compared with size-matched follicles from normal ovaries or polycystic ovaries from ovulatory women. This phenomenon appears to reflect a condition of advanced maturation of medium-sized antral follicles. The underlying basis for the abnormalities in anovulatory PCOS remains uncertain, but it is possible that there are intrinsic differences in folliculogenesis between polycystic and normal ovaries which affect preantral as well as antral follicles. An alternative - but not mutually exclusive - explanation of this disorder is the abnormal endocrine environment. Hypersecretion of both LH and insulin are typical of anovulatory women with PCOS. Studies in isolated granulosa cells, have shown, that insulin greatly augments the action of LH on steroidogenesis but this interaction may compromise further growth of medium-sized antral follicles by generation of 'preovulatory' concentrations of cAMP within the granulosa cell and thereby leading, prematurely, to terminal differentiation of granulosa cells.
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Affiliation(s)
- S Franks
- Department of Reproductive Science and Medicine, Imperial College School of Medicine, St Mary's Hospital, W2 1PG, London, UK
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