1
|
Renwick AN, Whitlock BK, Nestor CC, Daniel JA, Strickland L, Lear AS, Adkins M, Griffin C, Esteller-Vico A. Chronic inflammation decreases arcuate kisspeptin expression in male sheep. Domest Anim Endocrinol 2024; 89:106868. [PMID: 38901139 DOI: 10.1016/j.domaniend.2024.106868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/17/2024] [Accepted: 06/02/2024] [Indexed: 06/22/2024]
Abstract
Lipopolysaccharide (LPS) from Gram-negative bacteria induces an immune response and impairs reproduction through suppression of gonadotropin releasing hormone (GnRH), subsequently luteinizing hormone (LH) secretion. While there is evidence that acute inflammation inhibits kisspeptin, little is known about the impact of chronic inflammation on this key reproductive neuropeptide in livestock species. Thus, we sought to examine a central mechanism whereby LPS suppresses LH secretion in sheep. Twenty wethers were randomly assigned to one of five treatment groups: control (CON; n=4), single acute IV LPS dose (SAD; n=4), daily acute IV LPS dose (DAD; n=4), daily increasing IV LPS dose (DID; n=4), and chronic subcutaneous LPS dose (CSD; n=4). On Days 1 and 7, blood samples were collected every 12 minutes for 360 minutes using jugular venipuncture. Following blood collection on Day 7, all animals were euthanized, brain tissue was perfused with 4% paraformaldehyde, and hypothalamic blocks were removed and processed for immunohistochemistry. On Day 1, LH pulse frequency was significantly lower (p=0.02) in SAD (0.25 ± 0.1 pulses/hour), DAD (0.25 ± 0.1 pulses/hour), DID (0.35 ± 0.1 pulses/hour), and CSD (0.40 ± 0.1 pulses/hour) compared to CON (0.70 ±0.1 pulses/hour). On Day 7, only DID animals (0.35 ± 0.1 pulses/hour) had significantly lower (p=0.049) LH pulse frequency compared to controls (0.85 ± 0.1 pulse/hour). Furthermore, only DID animals (33.3 ± 10.9 cells/section/animal) had significantly fewer (p=0.001) kisspeptin-immunopositive cells compared to controls (82.6 ± 13.6 cells/section/animal). Taken together, we suggest that daily increasing doses of LPS is a powerful inhibitor of kisspeptin neurons in young male sheep and a physiologically relevant model to examine the impact of chronic inflammation on the reproductive axis in livestock.
Collapse
Affiliation(s)
- A N Renwick
- Large Animal Clinical Sciences Department, University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - B K Whitlock
- Large Animal Clinical Sciences Department, University of Tennessee College of Veterinary Medicine, Knoxville, TN.
| | - C C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, NC
| | - J A Daniel
- Animal Science Department, Berry College, Rome, GA
| | - L Strickland
- Large Animal Clinical Sciences Department, University of Tennessee College of Veterinary Medicine, Knoxville, TN; Department of Animal Science, University of Tennessee, Knoxville, TN
| | - A S Lear
- Large Animal Clinical Sciences Department, University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - M Adkins
- Large Animal Clinical Sciences Department, University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - C Griffin
- Large Animal Clinical Sciences Department, University of Tennessee College of Veterinary Medicine, Knoxville, TN
| | - A Esteller-Vico
- Biomedical and Diagnostic Sciences, University of Tennessee College of Veterinary Medicine, Knoxville, TN
| |
Collapse
|
2
|
Salmeri N, Viganò P, Cavoretto P, Marci R, Candiani M. The kisspeptin system in and beyond reproduction: exploring intricate pathways and potential links between endometriosis and polycystic ovary syndrome. Rev Endocr Metab Disord 2024; 25:239-257. [PMID: 37505370 DOI: 10.1007/s11154-023-09826-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/18/2023] [Indexed: 07/29/2023]
Abstract
Endometriosis and polycystic ovary syndrome (PCOS) are two common female reproductive disorders with a significant impact on the health and quality of life of women affected. A novel hypothesis by evolutionary biologists suggested that these two diseases are inversely related to one another, representing a pair of diametrical diseases in terms of opposite alterations in reproductive physiological processes but also contrasting phenotypic traits. However, to fully explain the phenotypic features observed in women with these conditions, we need to establish a potential nexus system between the reproductive system and general biological functions. The recent discovery of kisspeptin as pivotal mediator of internal and external inputs on the hypothalamic-pituitary-gonadal axis has led to a new understanding of the neuroendocrine upstream regulation of the human reproductive system. In this review, we summarize the current knowledge on the physiological roles of kisspeptin in human reproduction, as well as its involvement in complex biological functions such as metabolism, inflammation and pain sensitivity. Importantly, these functions are known to be dysregulated in both PCOS and endometriosis. Within the evolving scientific field of "kisspeptinology", we critically discuss the clinical relevance of these discoveries and their potential translational applications in endometriosis and PCOS. By exploring the possibilities of manipulating this complex signaling system, we aim to pave the way for novel targeted therapies in these reproductive diseases.
Collapse
Affiliation(s)
- Noemi Salmeri
- Gynecology and Obstetrics Unit, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Paola Viganò
- Infertility Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via M. Fanti 6, 20122, Milan, Italy.
| | - Paolo Cavoretto
- Gynecology and Obstetrics Unit, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| | - Roberto Marci
- Gynecology & Obstetrics, University of Ferrara, 44121, Ferrara, Italy
| | - Massimo Candiani
- Gynecology and Obstetrics Unit, IRCCS San Raffaele Scientific Institute, 20132, Milan, Italy
| |
Collapse
|
3
|
Nestor CC, Merkley CM, Lehman MN, Hileman SM, Goodman RL. KNDy neurons as the GnRH pulse generator: Recent studies in ruminants. Peptides 2023; 164:171005. [PMID: 36990389 PMCID: PMC10164117 DOI: 10.1016/j.peptides.2023.171005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/10/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023]
Abstract
This review considers three aspects of recent work on the role of KNDy neurons in GnRH pulse generation in ruminants. First, work on basic mechanisms of pulse generation includes several tests of this hypothesis, all of which support it, and evidence that Kiss1r-containing neurons form a positive feedback circuit with the KNDy neural network that strengthen the activity of this network. The second section on pathways mediating external inputs focuses on the influence of nutrition and photoperiod, and describes the evidence supporting roles for proopiomelanocortin (POMC) and agouti-related peptide (AgRP) afferents to KNDy cells in each of these. Finally, we review studies exploring the potential applications of manipulating signaling by kisspeptin, and the other KNDy peptides, to control reproductive function in domestic animals and conclude that, although these approaches show some promise, they do not have major advantages over current practices at this time.
Collapse
Affiliation(s)
- Casey C Nestor
- Department of Animal Science, North Carolina State University, Raleigh, NC, USA
| | | | - Michael N Lehman
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Stanley M Hileman
- Department of Physiology, Pharmacology, and Toxicology, West Virginia University, Morgantown, WV, USA
| | - Robert L Goodman
- Department of Physiology, Pharmacology, and Toxicology, West Virginia University, Morgantown, WV, USA.
| |
Collapse
|
4
|
Magata F, Tsukamura H, Matsuda F. The impact of inflammatory stress on hypothalamic kisspeptin neurons: Mechanisms underlying inflammation-associated infertility in humans and domestic animals. Peptides 2023; 162:170958. [PMID: 36682622 DOI: 10.1016/j.peptides.2023.170958] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/27/2022] [Accepted: 01/17/2023] [Indexed: 01/21/2023]
Abstract
Inflammatory diseases attenuate reproductive functions in humans and domestic animals. Lipopolysaccharide (LPS), an endotoxin released by bacteria, is known to disrupt female reproductive functions in various inflammatory diseases. LPS administration has been used to elucidate the impact of pathophysiological activation of the immune system on reproduction. Hypothalamic kisspeptin neurons are the master regulators of mammalian reproduction, mediating direct stimulation of hypothalamic gonadotropin-releasing hormone (GnRH) release and consequent release of gonadotropins, such as luteinizing hormone (LH) and follicle-stimulating hormone from the pituitary. The discovery of kisspeptin neurons in the mammalian hypothalamus has drastically advanced our understanding of how inflammatory stress causes reproductive dysfunction in both humans and domestic animals. Inflammation-induced ovarian dysfunction could be caused, at least partly, by aberrant GnRH and LH secretion, which is regulated by kisspeptin signaling. In this review, we focus on the effects of LPS on hypothalamic kisspeptin neurons to outline the impact of inflammatory stress on neuroendocrine regulation of mammalian reproductive systems. First, we summarize the attenuation of female reproduction by LPS during inflammation and the effects of LPS on ovarian and pituitary function. Second, we outline the inhibitory effects of LPS on pulsatile- and surge-mode GnRH/LH release. Third, we discuss the LPS-responsive hypothalamic-pituitary-adrenal axis and hypothalamic neural systems in terms of the cytokine-mediated pathway and the possible direct action of LPS via its hypothalamic receptors. This article describes the impact of LPS on hypothalamic kisspeptin neurons and the possible mechanisms underlying LPS-mediated disruption of LH pulses/surge via kisspeptin neurons.
Collapse
Affiliation(s)
- Fumie Magata
- Department of Veterinary Medical Sciences, the University of Tokyo, Tokyo 113-8657, Japan.
| | - Hiroko Tsukamura
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
| | - Fuko Matsuda
- Department of Veterinary Medical Sciences, the University of Tokyo, Tokyo 113-8657, Japan.
| |
Collapse
|
5
|
Hellier V, Dardente H, Lomet D, Cognié J, Dufourny L. Interactions between β-endorphin and kisspeptin neurons of the ewe arcuate nucleus are modulated by photoperiod. J Neuroendocrinol 2023; 35:e13242. [PMID: 36880357 DOI: 10.1111/jne.13242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023]
Abstract
Opioid peptides are well-known modulators of the central control of reproduction. Among them, dynorphin coexpressed in kisspeptin (KP) neurons of the arcuate nucleus (ARC) has been thoroughly studied for its autocrine effect on KP release through κ opioid receptors. Other studies have suggested a role for β-endorphin (BEND), a peptide cleaved from the pro-opiomelanocortin precursor, on food intake and central control of reproduction. Similar to KP, BEND content in the ARC of sheep is modulated by day length and BEND modulates food intake in a dose-dependent manner. Because KP levels in the ARC vary with photoperiodic and metabolic status, a photoperiod-driven influence of BEND neurons on neighboring KP neurons is plausible. The present study aimed to investigate a possible modulatory action of BEND on KP neurons located in the ovine ARC. Using confocal microscopy, numerous KP appositions on BEND neurons were found but there was no photoperiodic variation of the number of these interactions in ovariectomized, estradiol-replaced ewes. By contrast, BEND terminals on KP neurons were twice as numerous under short days, in ewes having an activated gonadotropic axis, compared to anestrus ewes under long days. Injection of 5 μg BEND into the third ventricle of short-day ewes induced a significant and specific increase of activated KP neurons (16% vs. 9% in controls), whereas the percentage of overall activated (c-Fos positive) neurons, was similar between both groups. These data suggest a photoperiod-dependent influence of BEND on KP neurons of the ARC, which may influence gonadotropin-releasing hormone pulsatile secretion and inform KP neurons about metabolic status.
Collapse
Affiliation(s)
- Vincent Hellier
- CNRS, IFCE, INRAE, Université de Tours, PRC, Nouzilly, France
| | - Hugues Dardente
- CNRS, IFCE, INRAE, Université de Tours, PRC, Nouzilly, France
| | - Didier Lomet
- CNRS, IFCE, INRAE, Université de Tours, PRC, Nouzilly, France
| | - Juliette Cognié
- CNRS, IFCE, INRAE, Université de Tours, PRC, Nouzilly, France
| | | |
Collapse
|
6
|
Magata F, Toda L, Sato M, Sakono T, Chambers JK, Uchida K, Tsukamura H, Matsuda F. Intrauterine LPS inhibited arcuate Kiss1 expression, LH pulses, and ovarian function in rats. Reproduction 2022; 164:207-219. [PMID: 36099331 DOI: 10.1530/rep-22-0047] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 09/12/2022] [Indexed: 11/08/2022]
Abstract
In brief Uterine inflammatory diseases are a major cause of infertility in humans and domestic animals. The current findings that intrauterine lipopolysaccharide is absorbed in systemic circulation and attenuates ovarian cyclic activities could provide a basis for developing novel treatments to improve fertility. Abstract Uterine inflammatory diseases are a major cause of infertility in humans and domestic animals. Circulating lipopolysaccharide (LPS), a bacterial endotoxin causing uterine inflammation, reportedly downregulates the hypothalamic-pituitary-gonadal axis to mediate ovarian dysfunction. In contrast, the mechanism whereby intrauterine LPS affects ovarian function has not been fully clarified. This study aimed to elucidate whether uterine exposure to LPS downregulates hypothalamic kisspeptin gene (Kiss1) expression, gonadotropin release, and ovarian function. Uterine inflammation was induced by intrauterine LPS administration to ovary-intact and ovariectomized female rats. As a result, plasma LPS concentrations were substantially higher in control rats until 48 h post injection, and the estrous cyclicity was disrupted with a prolonged diestrous phase. Three days post injection, the number of Graafian follicles and plasma estradiol concentration were reduced in LPS-treated rats, while numbers of Kiss1-expressing cells in the anteroventral periventricular nucleus and arcuate nucleus (ARC) were comparable in ovary-intact rats. Four days post injection, ovulation rate and plasma progesterone levels reduced significantly while gene expression of interleukin1β and tumor necrosis factor α was upregulated in the ovaries of LPS-treated rats that failed to ovulate. Furthermore, the number of Kiss1-expressing cells in the ARC and pulsatile luteinizing hormone (LH) release were significantly reduced in ovariectomized rats 24 h post injection. In conclusion, these results indicate that intrauterine LPS is absorbed in systemic circulation and attenuates ovarian function. This detrimental effect might be caused, at least partly, by the inhibition of ARC Kiss1 expression and LH pulses along with an induction of ovarian inflammatory response.
Collapse
Affiliation(s)
- Fumie Magata
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Lisa Toda
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Marimo Sato
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Takahiro Sakono
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - James K Chambers
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazuyuki Uchida
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroko Tsukamura
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Fuko Matsuda
- Department of Veterinary Medical Sciences, The University of Tokyo, Tokyo, Japan
| |
Collapse
|
7
|
Chen X, Huang L, Cui L, Xiao Z, Xiong X, Chen C. Sodium-glucose cotransporter 2 inhibitor ameliorates high fat diet-induced hypothalamic-pituitary-ovarian axis disorders. J Physiol 2022; 600:4549-4568. [PMID: 36048516 PMCID: PMC9826067 DOI: 10.1113/jp283259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 08/16/2022] [Indexed: 01/11/2023] Open
Abstract
High-fat diet (HFD) consumption is known to be associated with ovulatory disorders among women of reproductive age. Previous studies in animal models suggest that HFD-induced microglia activation contributes to hypothalamic inflammation. This causes the dysfunction of the hypothalamic-pituitary-ovarian (HPO) axis, leading to subfertility. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a novel class of lipid-soluble antidiabetic drugs that target primarily the early proximal tubules in kidney. Recent evidence revealed an additional expression site of SGLT2 in the central nervous system (CNS), indicating a promising role of SGLT2 inhibitors in the CNS. In type 2 diabetes patients and rodent models, SGLT2 inhibitors exhibit neuroprotective properties through reduction of oxidative stress, alleviation of cerebral atherosclerosis and suppression of microglia-induced neuroinflammation. Furthermore, clinical observations in patients with polycystic ovary syndrome (PCOS) demonstrated that SGLT2 inhibitors ameliorated patient anthropometric parameters, body composition and insulin resistance. Therefore, it is of importance to explore the central mechanism of SGLT2 inhibitors in the recovery of reproductive function in patients with PCOS and obesity. Here, we review the hypothalamic inflammatory mechanisms of HFD-induced microglial activation, with a focus on the clinical utility and possible mechanism of SGLT2 inhibitors in promoting reproductive fitness.
Collapse
Affiliation(s)
- Xiaolin Chen
- Department of EndocrinologyRenmin Hospital of Wuhan UniversityWuhanChina
| | - Lili Huang
- School of Biomedical ScienceUniversity of QueenslandBrisbaneQueenslandAustralia
| | - Ling Cui
- Department of Reproduction and InfertilityChengdu Women's and Children's Central HospitalSchool of MedicineUniversity of Electronic Science and Technology of ChinaChengduChina
| | - Zhuoni Xiao
- Reproductive Medical CenterRenmin Hospital of Wuhan UniversityWuhanChina
| | - Xiaoxing Xiong
- Department of NeurosurgeryRenmin Hospital of Wuhan UniversityWuhanChina
| | - Chen Chen
- School of Biomedical ScienceUniversity of QueenslandBrisbaneQueenslandAustralia
| |
Collapse
|
8
|
Dobson H, Routly JE, Smith RF. Understanding the trade-off between the environment and fertility in cows and ewes. Anim Reprod 2020; 17:e20200017. [PMID: 33029210 PMCID: PMC7534569 DOI: 10.1590/1984-3143-ar2020-0017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The environment contributes to production diseases that in turn badly affect cow performance, fertility and culling. Oestrus intensity is lower in lame cows, and in all cows 26% potential oestrus events are not expressed (to avoid getting pregnant). To understand these trade-offs, we need to know how animals react to their environment and how the environment influences hypothalamus-pituitary-adrenal axis (HPA) interactions with the hypothalamus-pituitary-ovarian axis (HPO). Neurotransmitters control secretion of GnRH into hypophyseal portal blood. GnRH/LH pulse amplitude and frequency drive oestradiol production, culminating in oestrus behaviour and a precisely-timed GnRH/LH surge, all of which are disrupted by poor environments. Responses to peripheral neuronal agents give clues about mechanisms, but do these drugs alter perception of stimuli, or suppress consequent responses? In vitro studies confirm some neuronal interactions between the HPA and HPO; and immuno-histochemistry clarifies the location and sequence of inter-neurone activity within the brain. In both species, exogenous corticoids, ACTH and/or CRH act at the pituitary (reduce LH release by GnRH), and hypothalamus (lower GnRH pulse frequency and delay surge release). This requires inter-neurones as GnRH cells do not have receptors for HPA compounds. There are two (simultaneous, therefore fail-safe?) pathways for CRH suppression of GnRH release via CRH-Receptors: one being the regulation of kisspeptin/dynorphin and other cell types in the hypothalamus, and the other being the direct contact between CRH and GnRH cell terminals in the median eminence. When we domesticate animals, we must provide the best possible environment otherwise animals trade-off with lower production, less intense oestrus behaviour, and impaired fertility. Avoiding life-time peri-parturient problems by managing persistent lactations in cows may be a worthy trade-off on both welfare and economic terms – better than the camouflage use of drugs/hormones/feed additives/intricate technologies? In the long term, getting animals and environment in a more harmonious balance is the ultimate strategy.
Collapse
Affiliation(s)
- Hilary Dobson
- Institute of Veterinary Science, University of Liverpool, Leahurst Campus, Neston, England
| | - Jean Elsie Routly
- Institute of Veterinary Science, University of Liverpool, Leahurst Campus, Neston, England
| | - Robert Frank Smith
- Institute of Veterinary Science, University of Liverpool, Leahurst Campus, Neston, England
| |
Collapse
|
9
|
Abstract
This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, CUNY, 65-30 Kissena Blvd., Flushing, NY, 11367, United States.
| |
Collapse
|
10
|
Barabás K, Szabó-Meleg E, Ábrahám IM. Effect of Inflammation on Female Gonadotropin-Releasing Hormone (GnRH) Neurons: Mechanisms and Consequences. Int J Mol Sci 2020; 21:ijms21020529. [PMID: 31947687 PMCID: PMC7014424 DOI: 10.3390/ijms21020529] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 02/06/2023] Open
Abstract
: Inflammation has a well-known suppressive effect on fertility. The function of gonadotropin-releasing hormone (GnRH) neurons, the central regulator of fertility is substantially altered during inflammation in females. In our review we discuss the latest results on how the function of GnRH neurons is modified by inflammation in females. We first address the various effects of inflammation on GnRH neurons and their functional consequences. Second, we survey the possible mechanisms underlying the inflammation-induced actions on GnRH neurons. The role of several factors will be discerned in transmitting inflammatory signals to the GnRH neurons: cytokines, kisspeptin, RFamide-related peptides, estradiol and the anti-inflammatory cholinergic pathway. Since aging and obesity are both characterized by reproductive decline our review also focuses on the mechanisms and pathophysiological consequences of the impact of inflammation on GnRH neurons in aging and obesity.
Collapse
Affiliation(s)
- Klaudia Barabás
- Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, H-7624 Pécs, Hungary;
| | - Edina Szabó-Meleg
- Departement of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary;
| | - István M. Ábrahám
- Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, H-7624 Pécs, Hungary;
- Correspondence:
| |
Collapse
|
11
|
Bidne KL, Dickson MJ, Ross JW, Baumgard LH, Keating AF. Disruption of female reproductive function by endotoxins. Reproduction 2018; 155:R169-R181. [DOI: 10.1530/rep-17-0406] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 01/22/2018] [Indexed: 12/20/2022]
Abstract
Endotoxemia can be caused by obesity, environmental chemical exposure, abiotic stressors and bacterial infection. Circumstances that deleteriously impact intestinal barrier integrity can induce endotoxemia, and controlled experiments have identified negative impacts of lipopolysaccharide (LPS; an endotoxin mimetic) on folliculogenesis, puberty onset, estrus behavior, ovulation, meiotic competence, luteal function and ovarian steroidogenesis. In addition, neonatal LPS exposures have transgenerational female reproductive impacts, raising concern about early life contacts to this endogenous reproductive toxicant. Aims of this review are to identify physiological stressors causing endotoxemia, to highlight potential mechanism(s) by which LPS compromises female reproduction and identify knowledge gaps regarding how acute and/or metabolic endotoxemia influence(s) female reproduction.
Collapse
|