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Is Hormone Replacement Therapy a Risk Factor or a Therapeutic Option for Alzheimer's Disease? Int J Mol Sci 2023; 24:ijms24043205. [PMID: 36834617 PMCID: PMC9964432 DOI: 10.3390/ijms24043205] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/21/2023] [Accepted: 01/23/2023] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder that accounts for more than half of all dementia cases in the elderly. Interestingly, the clinical manifestations of AD disproportionately affect women, comprising two thirds of all AD cases. Although the underlying mechanisms for these sex differences are not fully elucidated, evidence suggests a link between menopause and a higher risk of developing AD, highlighting the critical role of decreased estrogen levels in AD pathogenesis. The focus of this review is to evaluate clinical and observational studies in women, which have investigated the impact of estrogens on cognition or attempted to answer the prevailing question regarding the use of hormone replacement therapy (HRT) as a preventive or therapeutic option for AD. The articles were retrieved through a systematic review of the databases: OVID, SCOPUS, and PubMed (keywords "memory", "dementia," "cognition," "Alzheimer's disease", "estrogen", "estradiol", "hormone therapy" and "hormone replacement therapy" and by searching reference sections from identified studies and review articles). This review presents the relevant literature available on the topic and discusses the mechanisms, effects, and hypotheses that contribute to the conflicting findings of HRT in the prevention and treatment of age-related cognitive deficits and AD. The literature suggests that estrogens have a clear role in modulating dementia risk, with reliable evidence showing that HRT can have both a beneficial and a deleterious effect. Importantly, recommendation for the use of HRT should consider the age of initiation and baseline characteristics, such as genotype and cardiovascular health, as well as the dosage, formulation, and duration of treatment until the risk factors that modulate the effects of HRT can be more thoroughly investigated or progress in the development of alternative treatments can be made.
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Eslami-Amirabadi M, Sajjadi SA. The relation between thyroid dysregulation and impaired cognition/behaviour: An integrative review. J Neuroendocrinol 2021; 33:e12948. [PMID: 33655583 PMCID: PMC8087167 DOI: 10.1111/jne.12948] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 12/19/2020] [Accepted: 01/29/2021] [Indexed: 12/20/2022]
Abstract
Despite decades of research on the relation between thyroid diseases and cognition, the nature of this relationship remains elusive. An increasing prevalence of cognitive impairment and thyroid dysfunction has been consistently observed with ageing. Also, there appears to be an association between thyroid disorders and cognitive decline. Given the increasing global burden of dementia, elucidating the relationship between thyroid disorders as a potentially modifiable risk factor of cognitive impairment was the main goal of this review. We summarise the current literature examining the relationship between thyroid hormonal dysregulation and cognition or behaviour. We present the available imaging and pathological findings related to structural and functional brain changes related to thyroid hormonal dysregulation. We also propose potential mechanisms of interaction between thyroid hormones, autoantibodies and cognition/behaviour. Effects of gender, ethnicity and environmental factors are also briefly discussed. This review highlights the need for long-term prospective studies to capture the course of brain functional changes associated with the incidence and progression of thyroid dysregulations along with the confounding effects of non-modifiable risk factors such as gender and ethnicity. Moreover, double-blind controlled clinical trials are necessary to devise appropriate treatment plans to prevent cognitive consequences of over or undertreatment of thyroid disorders.
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Qin Y, An D, Xu W, Qi X, Wang X, Chen L, Chen L, Sha S. Estradiol Replacement at the Critical Period Protects Hippocampal Neural Stem Cells to Improve Cognition in APP/PS1 Mice. Front Aging Neurosci 2020; 12:240. [PMID: 32903757 PMCID: PMC7438824 DOI: 10.3389/fnagi.2020.00240] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/10/2020] [Indexed: 12/17/2022] Open
Abstract
It has been suggested that there is a critical window for estrogen replacement therapy (ERT) in postmenopausal women with Alzheimer’s disease (AD); however, supporting evidence is lacking. To address this issue, we investigated the effective period for estradiol (E2) treatment using a mouse model of AD. Four-month-old female APPswe/PSEN1dE9 (APP/PS1) mice were ovariectomized (OVX) and treated with E2 for 2 months starting at the age of 4 months (early period), 6 months (mid-period), or 8 months (late period). We then evaluated hippocampal neurogenesis, β-amyloid (Aβ) accumulation, telomerase activity, and hippocampal-dependent behavior. Compared to age-matched wild type mice, APP/PS1 mice with intact ovaries showed increased proliferation of hippocampal neural stem cells (NSCs) at 8 months of age and decreased proliferation of NSCs at 10 months of age; meanwhile, Aβ accumulation progressively increased with age, paralleling the reduced survival of immature neurons. OVX-induced depletion of E2 in APP/PS1 mice resulted in elevated Aβ levels accompanied by elevated p75 neurotrophin receptor (p75NTR) expression and increased NSC proliferation at 6 months of age, which subsequently declined; accelerated reduction of immature neurons starting from 6 months of age, and reduced telomerase activity and worsened memory performance at 10 months of age. Treatment with E2 in the early period post-OVX, rather than in the mid or late period, abrogated these effects, and p75NTR inhibition reduced the overproliferation of NSCs in 6-month-old OVX-APP/PS1 mice. Thus, E2 deficiency in young APP/PS1 mice exacerbates cognitive deficits and depletes the hippocampal NSC pool in later life; this can be alleviated by E2 treatment in the early period following OVX, which prevents Aβ/p75NTR-induced NSC overproliferation and preserves telomerase activity.
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Affiliation(s)
- Yaoyao Qin
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Dong An
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Weixing Xu
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Xiuting Qi
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Xiaoli Wang
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Ling Chen
- Department of Physiology, Nanjing Medical University, Nanjing, China.,State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing, China
| | - Lei Chen
- Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Sha Sha
- Department of Physiology, Nanjing Medical University, Nanjing, China.,State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing, China
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Loss of Estrogen Efficacy Against Hippocampus Damage in Long-Term OVX Mice Is Related to the Reduction of Hippocampus Local Estrogen Production and Estrogen Receptor Degradation. Mol Neurobiol 2020; 57:3540-3551. [PMID: 32542593 DOI: 10.1007/s12035-020-01960-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 05/28/2020] [Indexed: 10/24/2022]
Abstract
Postmenopausal women experience a higher risk for neurodegenerative diseases, including cognitive impairment and ischemic stroke. Many preclinical studies have indicated that estrogen replacement therapy (ERT) may provide protective effects against these neurological diseases. However, the results of Women's Health Initiative (WHI) studies have led to the proposal of "critical period hypothesis," which states that there is a precise window of opportunity for administering beneficial hormone therapy following menopause. However, the underlying molecular mechanisms require further characterization. Here, we explored the effects of ERT on cognition decline and global cerebral ischemia (GCI)-induced hippocampal neuronal damage in mice that had experienced both short-term (ovariectomized (OVX) 1 week) and long-term (OVX 10 weeks) estrogen deprivation. We also further explored the concentration of 17β-estradiol (E2) in the circulation and hippocampus and the expression of aromatase and estrogen receptors (ERα, ERα-Ser118, and ERβ). We found that the neuroprotective effectiveness of ERT against hippocampus damage exhibited in OVX1w mice was totally absent in OVX10w mice. Interestingly, the concentration of hippocampal E2 was irreversibly reduced in OVX10w mice, which was related to the decrease of aromatase expression in the hippocampus. In addition, long-term estrogen deprivation (LTED) led to a decrease in estrogen receptor proteins in the hippocampus. Thus, we concluded that the loss of ERT neuroprotection against hippocampus injury in LTED mice was related to the reduction in hippocampus E2 production and estrogen receptor degradation. These results provide several intervention targets to restore the effectiveness of ERT neuroprotection in elderly post-menopausal women.
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Guo H, Liu M, Zhang L, Wang L, Hou W, Ma Y, Ma Y. The Critical Period for Neuroprotection by Estrogen Replacement Therapy and the Potential Underlying Mechanisms. Curr Neuropharmacol 2020; 18:485-500. [PMID: 31976839 PMCID: PMC7457406 DOI: 10.2174/1570159x18666200123165652] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 12/03/2019] [Accepted: 01/14/2020] [Indexed: 01/13/2023] Open
Abstract
17β-Estradiol (estradiol or E2) is a steroid hormone that has been broadly applied as a neuroprotective therapy for a variety of neurodegenerative and cerebrovascular disorders such as ischemic stroke, Alzheimer's disease, and Parkinson's disease. Several laboratory and clinical studies have reported that Estrogen Replacement Therapy (ERT) had no effect against these diseases in elderly postmenopausal women, and at worst, increased their risk of onset and mortality. This review focuses on the growing body of data from in vitro and animal models characterizing the potential underlying mechanisms and signaling pathways that govern successful neuroprotection by ERT, including the roles of E2 receptors in mediating neuroprotection, E2 genomic regulation of apoptosis- related pathways, membrane-bound receptor-mediated non-genomic signaling pathways, and the antioxidant mechanisms of E2. Also discussed is the current evidence for a critical period of effective treatment with estrogen following natural or surgical menopause and the outcomes of E2 administration within an advantageous time period. The known mechanisms governing the duration of the critical period include depletion of E2 receptors, the switch to a ketogenic metabolic profile by neuronal mitochondria, and a decrease in acetylcholine that accompanies E2 deficiency. Also the major clinical trials and observational studies concerning postmenopausal Hormone Therapy (HT) are summarized to compare their outcomes with respect to neurological disease and discuss their relevance to the critical period hypothesis. Finally, potential controversies and future directions for this field are discussed throughout the review.
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Affiliation(s)
| | | | | | | | | | - Yaqun Ma
- Address correspondence to these authors at the Anesthesia and Operation Center, The First Medical Center to Chinese PLA General Hospital, Beijing 100853, China; Tel: +86 010 66938152; E-mail: and Department of Anesthesiology, The Seventh Medical Center to Chinese PLA General Hospital, Beijing 100700, China; E-mail:
| | - Yulong Ma
- Address correspondence to these authors at the Anesthesia and Operation Center, The First Medical Center to Chinese PLA General Hospital, Beijing 100853, China; Tel: +86 010 66938152; E-mail: and Department of Anesthesiology, The Seventh Medical Center to Chinese PLA General Hospital, Beijing 100700, China; E-mail:
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Schneider LS, Hernandez G, Zhao L, Franke AA, Chen YL, Pawluczyk S, Mack WJ, Brinton RD. Safety and feasibility of estrogen receptor-β targeted phytoSERM formulation for menopausal symptoms: phase 1b/2a randomized clinical trial. Menopause 2019; 26:874-884. [PMID: 30889096 PMCID: PMC6663614 DOI: 10.1097/gme.0000000000001325] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE PhytoSERM is a formulation of genistein, daidzein, and S-equol that has an 83-fold selective affinity for estrogen receptor-β (ERβ); and may enhance neuron function and estrogenic mechanisms in the brain without having peripheral estrogenic activity. METHODS We conducted an overarching, two-stage, dose-ranging, double-blinded, randomized, placebo-controlled trial of 12 weeks duration comparing 50 and 100 mg/d of phytoSERM with placebo for noncognitively impaired, perimenopausal women aged 45 to 60, with intact uteri and ovaries, with at least one cognitive complaint, and one vasomotor-related symptom. Primary objectives were to assess safety and tolerability of a 50 and 100 mg daily dose; and, secondly, to evaluate potential indicators of efficacy on cognition and vasomotor symptoms over 4 and 12 weeks, and using an embedded, 4-week, 2-period, placebo-controlled crossover trial for a subset of participants. RESULTS Seventy-one women were randomized to treatment; 70 were evaluated at 4 weeks; 12 were entered into the crossover study; 5 did not complete 12 weeks. Reasons for discontinuation were withdrawal of consent (n = 1) and lost to follow-up (n = 4). Adverse events occurred in 16.7% (n = 4) placebo, 39.1% (n = 9) 50 mg/d, and 29.2% (n = 7) 100 mg/d treated participants; 85% were mild and none was severe. Vaginal bleeding occurred in 0, placebo; 1, 50 mg; and 3, 100 mg/d participants. CONCLUSIONS The phytoSERM formulation was well tolerated at 50 and 100 mg daily doses. Based on safety outcomes, vaginal bleeding at the 100 mg dose, and vasomotor symptoms and cognitive outcomes at 12 weeks, a daily dose of 50 mg was considered preferable for a phase 2 efficacy trial.
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Affiliation(s)
- Lon S. Schneider
- Keck School of Medicine of the University of Southern California, Los Angeles, CA
| | | | - Liqin Zhao
- School of Pharmacy, University of Kansas, Lawrence, KS
| | | | - Yu-Ling Chen
- Keck School of Medicine of the University of Southern California, Los Angeles, CA
| | - Sonia Pawluczyk
- Keck School of Medicine of the University of Southern California, Los Angeles, CA
| | - Wendy J. Mack
- Keck School of Medicine of the University of Southern California, Los Angeles, CA
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Grković I, Mitrović N, Dragić M, Adžić M, Drakulić D, Nedeljković N. Spatial Distribution and Expression of Ectonucleotidases in Rat Hippocampus After Removal of Ovaries and Estradiol Replacement. Mol Neurobiol 2018; 56:1933-1945. [PMID: 29978426 DOI: 10.1007/s12035-018-1217-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/29/2018] [Indexed: 01/14/2023]
Abstract
Purinergic signaling is the main synaptic and non-synaptic signaling system in brain. ATP acts as a fast excitatory transmitter, while adenosine sets a global inhibitory tone within hippocampal neuronal networks. ATP and adenosine are interconnected by ectonucleotidase enzymes, which convert ATP to adenosine. Existing data point to the converging roles of ovarian steroids and purinergic signaling in synapse formation and refinement and synapse activity in the hippocampus. Therefore, in the present study, we have used enzyme histochemistry and expression analysis to obtain data on spatial distribution and expression of ecto-enzymes NTPDase1, NTPDase2, and ecto-5'-nucleotidase (eN) after removal of ovaries (OVX) and estradiol replacement (E2) in female rat hippocampus. The results show that target ectonucleotidases are predominantly localized in synapse-rich hippocampal layers. The most represented NTPDase in the hippocampal tissue is NTPDase2, being at the same time the mostly affected ectonucleotidase by OVX and E2. Specifically, OVX decreases the expression of NTPDase2 and eN, whereas E2 restores their expression to control level. Impact of OVX and E2 on ectonucleotidase expression was also examined in purified synaptosome (SYN) and gliosome (GLIO) fractions. Data reveal that SYN expresses NTPDase1 and NTPDase2, both of which are reduced following OVX and restored with E2. GLIO exhibits NTPDase2-mediated ATP hydrolysis, which falls in OVX, and recovers by E2. These changes in the activity occur without parallel changes in NTPDase2-protein abundance. The same holds for eN. The lack of correlation between NTPDase2 and eN activities and their respective protein abundances suggest a non-genomic mode of E2 action, which is studied further in primary astrocyte culture. Since ovarian steroids shape hippocampal synaptic networks and regulate ectonucleotidase activities, it is possible that cognitive deficits seen after ovary removal may arise from the loss of E2 modulatory actions on ectonucleotidase expression in the hippocampus.
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Affiliation(s)
- Ivana Grković
- Department of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, 11001, Serbia.
| | - Nataša Mitrović
- Department of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, 11001, Serbia
| | - Milorad Dragić
- Department of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, 11001, Serbia
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia
| | - Marija Adžić
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia
| | - Dunja Drakulić
- Department of Molecular Biology and Endocrinology, Vinča Institute of Nuclear Sciences, University of Belgrade, Mike Petrovića Alasa 12-14, Belgrade, 11001, Serbia
| | - Nadežda Nedeljković
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia
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Galvankar M, Singh N, Modi D. Estrogen is essential but not sufficient to induce endometriosis. J Biosci 2018; 42:251-263. [PMID: 28569249 DOI: 10.1007/s12038-017-9687-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Endometriosis is a common gynaecological disorder of unknown aetiology. Among the several factors, estrogen has been implicated as a causative factor in endometriosis. In the present study using mouse model, we assessed the role of estrogen in the initial implantation and growth of endometrium in ectopic locations. Uterine tissues from green fluorescent protein (GFP) mice were transplanted in to the peritoneum of wild type mice in presence and absence of estrogen. As compared to untreated controls, the implantation of uterine tissue at ectopic locations was higher when estrogen was administered to both host and donor animals. However, this effect was not sustained as lesions regressed within 14 days of treatment. Irrespective of the treatment, peritoneal adipose was the most preferred site of lesion establishment. The lesions did not have typical features of the endometriosis (presence of glands and stroma) even after estrogen treatment and the ectopic tissue underwent regression by apoptosis irrespective of treatment. Since estrogen promotes implantation of endometrial tissue to ectopic locations but failure of these ectopic lesions to grow and sustain even in high estrogenic environment we propose that estrogen is necessary but not sufficient to sustain endometriosis.
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Affiliation(s)
- Mosami Galvankar
- Molecular and Cellular Biology Laboratory, National Institute for Research in Reproductive Health, Mumbai 400 012, India
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Payrits M, Sághy É, Cseko K, Pohóczky K, Bölcskei K, Ernszt D, Barabás K, Szolcsányi J, Ábrahám IM, Helyes Z, Szoke É. Estradiol Sensitizes the Transient Receptor Potential Vanilloid 1 Receptor in Pain Responses. Endocrinology 2017; 158:3249-3258. [PMID: 28977586 DOI: 10.1210/en.2017-00101] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 06/29/2017] [Indexed: 11/19/2022]
Abstract
Sex differences exist in chronic pain pathologies, and gonadal estradiol (E2) alters the pain sensation. The nocisensor transient receptor potential vanilloid 1 (TRPV1) receptor plays a critical role in triggering pain. Here we examined the impact of E2 on the function of TRPV1 receptor in mice sensory neurons in vitro and in vivo. Both mechano- and thermonociceptive thresholds of the plantar surface of the paw of female mice were significantly lower in proestrus compared with the estrus phase. These thresholds were higher in ovariectomized (OVX) mice and significantly lower in sham-operated mice in proestrus compared with the sham-operated mice in estrus phase. This difference was absent in TRPV1 receptor-deficient mice. Furthermore, E2 potentiated the TRPV1 receptor activation-induced mechanical hyperalgesia in OVX mice. Long pretreatment (14 hours) with E2 induced a significant increase in TRPV1 receptor messenger RNA expression and abolished the capsaicin-induced TRPV1 receptor desensitization in primary sensory neurons. The short E2 incubation (10 minutes) also prevented the desensitization, which reverted after coadministration of E2 and the tropomyosin-related kinase A (TrkA) receptor inhibitor. Our study provides in vivo and in vitro evidence for E2-induced TRPV1 receptor upregulation and sensitization mediated by TrkAR via E2-induced genomic and nongenomic mechanisms. The sensitization and upregulation of TRPV1 receptor by E2 in sensory neurons may explain the greater pain sensitivity in female mice.
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Affiliation(s)
- Maja Payrits
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Hungary
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
| | - Éva Sághy
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Hungary
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089, Budapest, Hungary
| | - Kata Cseko
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Hungary
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
| | - Krisztina Pohóczky
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Hungary
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
| | - Kata Bölcskei
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Hungary
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
| | - Dávid Ernszt
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
- Department of Pharmaceutical Biotechnology, University of Pécs, Medical School, H-7624 Pécs, Hungary
| | - Klaudia Barabás
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
- Institute of Physiology, University of Pécs, Medical School, H-7624 Pécs, Hungary
| | - János Szolcsányi
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Hungary
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
| | - István M Ábrahám
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
- Institute of Physiology, University of Pécs, Medical School, H-7624 Pécs, Hungary
- MTA-PTE NAP B Molecular Neuroendocrinology Research Group-Hungary, H-7624 Pécs, Hungary
- Centre for Neuroscience, University of Pécs, H-7624 Pécs, Hungary
| | - Zsuzsanna Helyes
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Hungary
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
- Centre for Neuroscience, University of Pécs, H-7624 Pécs, Hungary
- MTA-PTE NAP B Chronic Pain Research Group-Hungary, H-7624 Pécs, Hungary
| | - Éva Szoke
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, H-7624 Pécs, Hungary
- Janos Szentagothai Research Centre, University of Pécs, H-7624 Pécs, Hungary
- MTA-PTE NAP B Chronic Pain Research Group-Hungary, H-7624 Pécs, Hungary
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Arevalo MA, Azcoitia I, Gonzalez-Burgos I, Garcia-Segura LM. Signaling mechanisms mediating the regulation of synaptic plasticity and memory by estradiol. Horm Behav 2015; 74:19-27. [PMID: 25921586 DOI: 10.1016/j.yhbeh.2015.04.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 04/02/2015] [Accepted: 04/20/2015] [Indexed: 01/29/2023]
Abstract
This article is part of a Special Issue "Estradiol and Cognition". Estradiol participates in the regulation of the function and plasticity of synaptic circuits in key cognitive brain regions, such as the prefrontal cortex and the hippocampus. The mechanisms elicited by estradiol are mediated by the regulation of transcriptional activity by nuclear estrogen receptors and by intracellular signaling cascades activated by estrogen receptors associated with the plasma membrane. In addition, the mechanisms include the interaction of estradiol with the signaling of other factors involved in the regulation of cognition, such as brain derived neurotrophic factor, insulin-like growth factor-1 and Wnt. Modifications in these signaling pathways by aging or by a long-lasting ovarian hormone deprivation after menopause may impair the enhancing effects of estradiol on synaptic plasticity and cognition.
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Affiliation(s)
- Maria-Angeles Arevalo
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avenida Doctor Arce 37, E-28002 Madrid, Spain
| | - Iñigo Azcoitia
- Department of Cell Biology, Faculty of Biology, Universidad Complutense, Calle José Antonio Novais 12, Ciudad Universitaria, E-28040 Madrid, Spain
| | - Ignacio Gonzalez-Burgos
- Laboratorio de Psicobiología, División de Neurociencias, Centro de Investigación Biomédica de Occidente, Instituto Mexicano del Seguro Social, Guadalajara, Jal. Mexico
| | - Luis M Garcia-Segura
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Avenida Doctor Arce 37, E-28002 Madrid, Spain.
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Yin W, Maguire SM, Pham B, Garcia AN, Dang NV, Liang J, Wolfe A, Hofmann HA, Gore AC. Testing the Critical Window Hypothesis of Timing and Duration of Estradiol Treatment on Hypothalamic Gene Networks in Reproductively Mature and Aging Female Rats. Endocrinology 2015; 156:2918-33. [PMID: 26018250 PMCID: PMC4511137 DOI: 10.1210/en.2015-1032] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
At menopause, the dramatic loss of ovarian estradiol (E2) necessitates the adaptation of estrogen-sensitive neurons in the hypothalamus to an estrogen-depleted environment. We developed a rat model to test the "critical window" hypothesis of the effects of timing and duration of E2 treatment after deprivation on the hypothalamic neuronal gene network in the arcuate nucleus and the medial preoptic area. Rats at 2 ages (reproductively mature or aging) were ovariectomized and given E2 or vehicle replacement regimes of differing timing and duration. Using a 48-gene quantitative low-density PCR array and weighted gene coexpression network analysis, we identified gene modules differentially regulated by age, timing, and duration of E2 treatment. Of particular interest, E2 status differentially affected suites of genes in the hypothalamus involved in energy balance, circadian rhythms, and reproduction. In fact, E2 status was the dominant factor in determining gene modules and hormone levels; age, timing, and duration had more subtle effects. Our results highlight the plasticity of hypothalamic neuroendocrine systems during reproductive aging and its surprising ability to adapt to diverse E2 replacement regimes.
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Affiliation(s)
- Weiling Yin
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
| | - Sean M Maguire
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
| | - Brian Pham
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
| | - Alexandra N Garcia
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
| | - Nguyen-Vy Dang
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
| | - Jingya Liang
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
| | - Andrew Wolfe
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
| | - Hans A Hofmann
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
| | - Andrea C Gore
- Division of Pharmacology and Toxicology (W.Y., B.P., N.-V.D., J.L., A.C.G.), Departments of Integrative Biology (S.M.M., H.A.H.) and Psychology (A.N.G., A.C.G.), and Institute for Neuroscience (H.A.H., A.C.G.), The University of Texas at Austin, Austin, Texas 78712; and Johns Hopkins University School of Medicine (A.W.), Baltimore, Maryland 21287
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12
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Kennedy DO. Polyphenols and the human brain: plant “secondary metabolite” ecologic roles and endogenous signaling functions drive benefits. Adv Nutr 2014; 5:515-33. [PMID: 25469384 PMCID: PMC4188223 DOI: 10.3945/an.114.006320] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Flavonoids and other polyphenols are ubiquitous plant chemicals that fulfill a range of ecologic roles for their home plant, including protection from a range of biotic and abiotic stressors and a pivotal role in the management of pathogenic and symbiotic soil bacteria and fungi. They form a natural part of the human diet, and evidence suggests that their consumption is associated with the beneficial modulation of a number of health-related variables, including those related to cardiovascular and brain function. Over recent years, the consensus as to the mechanisms responsible for these effects in humans has shifted away from polyphenols having direct antioxidant effects and toward their modulation of cellular signal transduction pathways. To date, little consideration has been given to the question of why, rather than how, these plant-derived chemicals might exert these effects. Therefore, this review summarizes the evidence suggesting that polyphenols beneficially affect human brain function and describes the current mechanistic hypotheses explaining these effects. It then goes on to describe the ecologic roles and potential endogenous signaling functions that these ubiquitous phytochemicals play within their home plant and discusses whether these functions drive their beneficial effects in humans via a process of “cross-kingdom” signaling predicated on the many conserved similarities in plant, microbial, and human cellular signal transduction pathways.
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13
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Regulation of object recognition and object placement by ovarian sex steroid hormones. Behav Brain Res 2014; 285:140-57. [PMID: 25131507 DOI: 10.1016/j.bbr.2014.08.001] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 07/29/2014] [Accepted: 08/01/2014] [Indexed: 12/26/2022]
Abstract
The ovarian hormones 17β-estradiol (E2) and progesterone (P4) are potent modulators of hippocampal memory formation. Both hormones have been demonstrated to enhance hippocampal memory by regulating the cellular and molecular mechanisms thought to underlie memory formation. Behavioral neuroendocrinologists have increasingly used the object recognition and object placement (object location) tasks to investigate the role of E2 and P4 in regulating hippocampal memory formation in rodents. These one-trial learning tasks are ideal for studying acute effects of hormone treatments on different phases of memory because they can be administered during acquisition (pre-training), consolidation (post-training), or retrieval (pre-testing). This review synthesizes the rodent literature testing the effects of E2 and P4 on object recognition (OR) and object placement (OP), and the molecular mechanisms in the hippocampus supporting memory formation in these tasks. Some general trends emerge from the data. Among gonadally intact females, object memory tends to be best when E2 and P4 levels are elevated during the estrous cycle, pregnancy, and in middle age. In ovariectomized females, E2 given before or immediately after testing generally enhances OR and OP in young and middle-aged rats and mice, although effects are mixed in aged rodents. Effects of E2 treatment on OR and OP memory consolidation can be mediated by both classical estrogen receptors (ERα and ERβ), and depend on glutamate receptors (NMDA, mGluR1) and activation of numerous cell signaling cascades (e.g., ERK, PI3K/Akt, mTOR) and epigenetic processes (e.g., histone acetylation, DNA methylation). Acute P4 treatment given immediately after training also enhances OR and OP in young and middle-aged ovariectomized females by activating similar cell signaling pathways as E2 (e.g., ERK, mTOR). The few studies that have administered both hormones in combination suggest that treatment can enhance OR and OP, but that effects are highly dependent on factors such as dose and timing of administration. In addition to providing more detail on these general conclusions, this review will discuss directions for future avenues of research into the hormonal regulation of object memory.
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14
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Scott EL, Zhang QG, Vadlamudi RK, Brann DW. Premature menopause and risk of neurological disease: basic mechanisms and clinical implications. Mol Cell Endocrinol 2014; 389:2-6. [PMID: 24462786 PMCID: PMC4040297 DOI: 10.1016/j.mce.2014.01.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/14/2014] [Accepted: 01/14/2014] [Indexed: 10/25/2022]
Abstract
Since basic scientific studies in the 1990s revealed dramatic gender differences in neurological damage from cerebral ischemia, significant evidence has accumulated for a neuroprotective role of ovarian-derived 17β-Estradiol (E2). Intriguingly, observational studies have further suggested that early and prolonged loss of ovarian E2 (premature menopause) leads to a doubled lifetime risk for dementia and a fivefold increased risk of mortality from neurological disorders, but some controversy remains. Here, we briefly summarize and analyze clinical cohort studies assessing the detrimental neurological outcomes of premature menopause. Furthermore, we discuss current basic science studies elucidating the molecular mechanisms underlying the enhanced risk of neurological disease in prematurely menopausal women and the "window of opportunity" for estrogen benefit. Finally, we highlight four critical issues in the field that require collaboration between basic scientists and clinicians for successful resolution, with the ultimate goal of maintaining optimal neurological health in prematurely menopausal women.
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Affiliation(s)
- Erin L Scott
- University System of Georgia MD/PhD Program, Georgia Regents University, Augusta, GA 30912, USA; Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, GA 30912, USA
| | - Quan-Guang Zhang
- Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, GA 30912, USA
| | - Ratna K Vadlamudi
- Department of Obstetrics and Gynecology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Darrell W Brann
- Institute of Molecular Medicine and Genetics, Georgia Regents University, Augusta, GA 30912, USA.
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15
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Soni M, Rahardjo TBW, Soekardi R, Sulistyowati Y, Lestariningsih, Yesufu-Udechuku A, Irsan A, Hogervorst E. Phytoestrogens and cognitive function: a review. Maturitas 2014; 77:209-20. [PMID: 24486046 DOI: 10.1016/j.maturitas.2013.12.010] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 12/22/2013] [Indexed: 02/04/2023]
Abstract
Neuroprotective effects of phytoestrogen compounds (found in soy) have been demonstrated in animal research and cell culture studies. In particular, phytoestrogens have been shown to reduce Alzheimer's Disease (AD) related pathology, potentially alleviating risk of AD progression. In addition to their antioxidant properties, soy products also have the ability to affect cognition via interaction with estrogen receptors. However, observational studies and randomised controlled trials in humans have resulted in inconclusive findings within this domain. There are several possible reasons for these discrepant data. Studies which report no effect of phytoestrogens on cognition have mainly been carried out in European cohorts, with an average low dietary consumption. In contrast, investigation of Asian populations, with a higher general intake of tofu (a non-fermented soy product) have shown negative associations with cognitive function in those over the age of 65. Consideration of type of soy product is important, as in the latter sample, protective effects of tempe (fermented soy) were also observed. Limited data provide evidence that effects of phytoestrogens on cognition may be modified by dosage, duration of consumption and cognitive test used. Additionally, characteristics of the study population including age, gender, ethnicity and menopausal status appear to be mediating variables. Phytoestrogen treatment interventions have also shown time-limited positive effects on cognition. These findings are consistent with estrogen treatment studies, where initial positive short-term cognitive effects may occur, which reverse with long-term continuous use in elderly women. Well controlled, large scale studies are needed to assess the effects of phytoestrogens on the aging brain and provide further understanding of this association.
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Affiliation(s)
- Mira Soni
- School of Sport, Exercise and Health Sciences, Loughborough University, United Kingdom.
| | | | - Rodiyah Soekardi
- Department of Public Health, Respati University Yogyakarta, Indonesia
| | | | - Lestariningsih
- Department of Public Health, Respati University Yogyakarta, Indonesia
| | - Amina Yesufu-Udechuku
- Centre for Outcomes Research and Effectiveness, Research Department of Clinical, Educational and Health Psychology, University College London, 1-19 Torrington Place, W1CE 4HB, UK
| | - Atik Irsan
- Department of Nutrition, University of Bogor, Bogor Indonesia
| | - Eef Hogervorst
- School of Sport, Exercise and Health Sciences, Loughborough University, United Kingdom; Department of Public Health, Respati University Yogyakarta, Indonesia
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16
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Neese SL, Pisani SL, Doerge DR, Helferich WG, Sepehr E, Chittiboyina AG, Rotte SCK, Smillie TJ, Khan IA, Korol DL, Schantz SL. The effects of dietary treatment with S-equol on learning and memory processes in middle-aged ovariectomized rats. Neurotoxicol Teratol 2014; 41:80-8. [PMID: 24368316 PMCID: PMC3943933 DOI: 10.1016/j.ntt.2013.12.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 11/22/2013] [Accepted: 12/17/2013] [Indexed: 01/18/2023]
Abstract
The use of over-the-counter botanical estrogens containing isolated soy isoflavones, including genistein and daidzein, has become a popular alternative to traditional hormone therapies. Menopausal women use these products as an aide in healthy aging, including for the maintenance of cognitive function. The safety and efficacy of many of these commercial preparations remain unknown. Previous research in our lab found that treatment of ovariectomized (OVX) female Long-Evans rats with genistein impaired working memory in an operant delayed spatial alternation (DSA) task and response learning in a plus-maze, but enhanced place learning assessed in the plus-maze. The present study further examined the effects of isolated isoflavones on working memory and place learning by treating middle-aged (12-13 month old) OVX female Long-Evans rats with S-equol, the exclusive enantiomer produced by metabolism of daidzein in the mammalian gut. S-equol binds selectively to ERβ with an affinity similar to that of genistein but has low transcriptional potency. For DSA testing, S-equol at 1.94, 0.97 mg, or 0mg (sucrose control) was orally administered to animals daily, 30 min before behavioral testing, and again both 4 and 8 hours after the first treatment. Rats were tested on the DSA task following the first, morning dose. For place learning, rats received 0.97 mg S-equol every 4 hours during the light portion of the cycle beginning 48 hours prior to behavioral testing (total exposure 8.7 mg S-equol). S-equol treatment was largely without effect on the DSA and place learning tasks. This is the first study to test the behavioral effects of isolated S-equol in OVX rodents, and shows that, unlike genistein or estradiol, repeated daily treatment with this isoflavone metabolite does not alter learning and memory processes in middle-aged OVX rats.
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Affiliation(s)
- Steven L Neese
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001S. Lincoln Avenue, Urbana, IL 61802, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, USA; Department of Psychology and Neuroscience, Baldwin Wallace University, 275 Eastland Road, Berea, OH 44017, USA.
| | - Samantha L Pisani
- Neuroscience Program, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, USA.
| | - Daniel R Doerge
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079-9502, USA.
| | - William G Helferich
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, 905S Goodwin Avenue, Urbana, IL 61801, USA.
| | - Estatira Sepehr
- Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR 72079-9502, USA.
| | - Amar G Chittiboyina
- National Center for Natural Product Research, University of Mississippi, 3011 Thad Cochran Research Center, University, MS 38677, USA.
| | - Sateesh Chandra Kumar Rotte
- National Center for Natural Product Research, University of Mississippi, 3011 Thad Cochran Research Center, University, MS 38677, USA.
| | - Troy J Smillie
- National Center for Natural Product Research, University of Mississippi, 3011 Thad Cochran Research Center, University, MS 38677, USA.
| | - Ikhlas A Khan
- National Center for Natural Product Research, University of Mississippi, 3011 Thad Cochran Research Center, University, MS 38677, USA.
| | - Donna L Korol
- Neuroscience Program, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, USA; Department of Biology, Syracuse University, 107 College Place, Syracuse, NY 13244, USA.
| | - Susan L Schantz
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 2001S. Lincoln Avenue, Urbana, IL 61802, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, USA.
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17
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Rao YS, Mott NN, Wang Y, Chung WCJ, Pak TR. MicroRNAs in the aging female brain: a putative mechanism for age-specific estrogen effects. Endocrinology 2013; 154:2795-806. [PMID: 23720423 PMCID: PMC3713211 DOI: 10.1210/en.2013-1230] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 05/21/2013] [Indexed: 11/19/2022]
Abstract
Menopause is characterized by the rapid age-related decline of circulating 17β-estradiol (E(2)) levels in women, which can sometimes result in cognitive disorders such as impaired memory and increased anxiety. Hormone therapy (HT) is a widely used treatment for the adverse effects associated with menopause; however, evidence suggests that HT administered to postmenopausal women age 65 years and over can lead to increased risks for cognitive disorders. We hypothesized that these age-related changes in E(2) action are due to posttranscriptional gene regulation by microRNAs (miRNAs). miRNAs are a class of small noncoding RNAs that regulate gene expression by binding to the 3'-untranslated region of target mRNAs and subsequently target these transcripts for degradation. In the present study, 3- and 18-month-old female rats were oophorectomized (OVX) and treated 1 week after surgery with 2.5 μg E(2) once per day for 3 days. Total RNA was isolated from the ventral and dorsal hippocampus, central amygdala, and paraventricular nucleus. Our results showed that E(2) differentially altered miRNA levels in an age- and brain region-dependent manner. Multiple miRNA target prediction algorithms revealed putative target genes that are important for memory and stress regulation, such as BDNF, glucocorticoid receptor, and SIRT-1. Indeed, quantitative RT-PCR analyses of some of the predicted targets, such as SIRT1, showed that the mRNA expression levels were the inverse of the targeting miRNA, thereby confirming the prediction algorithms. Taken together, these data show that E(2) regulates miRNA expression in an age- and E(2)-dependent manner, which we hypothesize results in differential gene expression and consequently altered neuronal function.
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Affiliation(s)
- Yathindar S Rao
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
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18
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Sánchez MG, Morissette M, Di Paolo T. Oestradiol modulation of serotonin reuptake transporter and serotonin metabolism in the brain of monkeys. J Neuroendocrinol 2013; 25:560-9. [PMID: 23414342 DOI: 10.1111/jne.12034] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 02/04/2023]
Abstract
Serotonin (5-hydroxytryptamine; 5-HT) is an important brain neurotransmitter that is implicated in mental and neurodegenerative diseases and is modulated by ovarian hormones. Nevertheless, the effect of oestrogens on 5-HT neurotransmission in the primate caudate nucleus, putamen and nucleus accumbens, which are major components of the basal ganglia, and the anterior cerebral cortex, mainly the frontal and cingulate gyrus, is not well documented. The present study evaluated 5-HT reuptake transporter (SERT) and 5-HT metabolism in these brain regions in response to 1-month treatment with 17β-oestradiol in short-term (1 month) ovariectomised (OVX) monkeys (Macaca fascicularis). SERT-specific binding was measured by autoradiography using the radioligand [³H]citalopram. Biogenic amine concentrations were quantified by high-performance liquid chromatography. 17β-Oestradiol increased SERT in the superior frontal cortex and in the anterior cingulate cortex, in the nucleus accumbens, and in subregions of the caudate nucleus of OVX monkeys. 17β-Oestradiol left [³H]citalopram-specific binding unchanged in the putamen, as well as the dorsal and medial raphe nucleus. 17β-Oestradiol treatment decreased striatal concentrations of the precursor of 5-HT, 5-hydroxytryptophan, and increased 5-HT, dopamine and 3-methoxytyramine concentrations in the nucleus accumbens, caudate nucleus and putamen, whereas the concentrations of the metabolites 5-hydroxyindoleacetic acid, 3,4-dihydroxyphenylacetic acid and homovanillic acid remained unchanged. No effect of 17β-oestradiol treatment was observed for biogenic amine concentrations in the cortical regions. A significant positive correlation was observed between [³H]citalopram-specific binding and 5-HT concentrations in the caudate nucleus, putamen and nucleus accumbens, suggesting their link. These results have translational value for women with low oestrogen, such as those in surgical menopause or perimenopause.
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Affiliation(s)
- M G Sánchez
- Neuroscience Research Unit, Centre hospitalier universitaire de Québec, Quebec City, Quebec, Canada
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19
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Sumien N, Chaudhari K, Sidhu A, Forster MJ. Does phytoestrogen supplementation affect cognition differentially in males and females? Brain Res 2013; 1514:123-7. [PMID: 23415935 DOI: 10.1016/j.brainres.2013.02.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 01/16/2013] [Accepted: 02/09/2013] [Indexed: 11/26/2022]
Abstract
Phytoestrogens are plant-derived compounds found mainly in soy with known estrogenic properties and a potential for benefits to human health. Increased intake in phytoestrogens stemmed from the search for safe alternatives to hormone replacement therapies. Based on epidemiologic evidence comparing Western and Asian populations and clinical studies, phytoestrogens show promise to improve health and brain function. This review is focused on the effects of phytoestrogens on cognition by examining clinical and animal studies, with special attention placed on (1) a window of therapeutic opportunity which may explain the discrepancy among studies, and (2) whether a sex/gender difference exists in response to phytoestrogen intake and what the possible underlying mechanisms may be.
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Affiliation(s)
- Nathalie Sumien
- Department of Pharmacology and Neuroscience, UNT Health Science Center at Fort Worth, Institute for Aging and Alzheimer's Disease Research, Fort Worth, TX 76107, USA.
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20
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Daniel JM. Estrogens, estrogen receptors, and female cognitive aging: the impact of timing. Horm Behav 2013; 63:231-7. [PMID: 22587940 DOI: 10.1016/j.yhbeh.2012.05.003] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 05/04/2012] [Accepted: 05/07/2012] [Indexed: 10/28/2022]
Abstract
Estrogens have been shown to be protective agents against neurodegeneration and associated cognitive decline in aging females. However, clinical data have been equivocal as to the benefits to the brain and cognition of estrogen therapy in postmenopausal women. One factor that is proposed to be critical in determining the efficacy of hormone therapy is the timing of its initiation. The critical period or window of opportunity hypothesis proposes that following long-term ovarian hormone deprivation, the brain and cognition become insensitive to exogenously administered estrogens. In contrast, if estrogens are administered during a critical period near the time of cessation of ovarian function, they will exert beneficial effects. The focus of the current review is the examination of evidence from rodent models investigating the critical period hypothesis. A growing body of experimental data indicates that beneficial effects of 17β-estradiol (estradiol) on cognition and on cholinergic function and hippocampal plasticity, both of which have been linked to the ability of estradiol to exert beneficial effects on cognition, are attenuated if estradiol is administered following a period of long-term ovarian hormone deprivation. Further, emerging data implicate loss of estrogen receptor alpha (ERα) in the brain resulting from long-term hormone deprivation as a basis for the existence of the critical period. A unifying model is proposed by which the presence or absence of estrogens during a critical period following the cessation of ovarian function permanently alters the system resulting in decreased or increased risk, respectively, of neurodegeneration and cognitive decline.
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Affiliation(s)
- Jill M Daniel
- Department of Psychology and Program in Neuroscience, Tulane University, New Orleans, LA 70118, USA.
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21
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Frick KM. Building a better hormone therapy? How understanding the rapid effects of sex steroid hormones could lead to new therapeutics for age-related memory decline. Behav Neurosci 2012; 126:29-53. [PMID: 22289043 DOI: 10.1037/a0026660] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A wealth of data collected in recent decades has demonstrated that ovarian sex-steroid hormones, particularly 17β-estradiol (E2), are important trophic factors that regulate the function of cognitive regions of the brain such as the hippocampus. The loss of hormone cycling at menopause is associated with cognitive decline and dementia in women, and the onset of memory decline in animal models. However, hormone therapy is not currently recommended to prevent or treat cognitive decline, in part because of its detrimental side effects. In this article, it is proposed that investigations of the rapid effects of E2 on hippocampal function be used to further the design of new drugs that mimic the beneficial effects of E2 on memory without the side effects of current therapies. A conceptual model is presented for elucidating the molecular and biochemical mechanisms through which sex-steroid hormones modulate memory, and a specific hypothesis is proposed to account for the rapid memory-enhancing effects of E2. Empirical support for this hypothesis is discussed as a means of stimulating the consideration of new directions for the development of hormone-based therapies to preserve memory function in menopausal women.
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Affiliation(s)
- Karyn M Frick
- Department of Psychology, University of Wisconsin-Milwaukee, 2441 East Hartford Avenue, Milwaukee, WI 53211, USA.
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22
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Scott E, Zhang QG, Wang R, Vadlamudi R, Brann D. Estrogen neuroprotection and the critical period hypothesis. Front Neuroendocrinol 2012; 33:85-104. [PMID: 22079780 PMCID: PMC3288697 DOI: 10.1016/j.yfrne.2011.10.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 10/21/2011] [Accepted: 10/24/2011] [Indexed: 12/15/2022]
Abstract
17β-Estradiol (estradiol or E2) is implicated as a neuroprotective factor in a variety of neurodegenerative disorders. This review focuses on the mechanisms underlying E2 neuroprotection in cerebral ischemia, as well as emerging evidence from basic science and clinical studies, which suggests that there is a "critical period" for estradiol's beneficial effect in the brain. Potential mechanisms underlying the critical period are discussed, as are the neurological consequences of long-term E2 deprivation (LTED) in animals and in humans after natural menopause or surgical menopause. We also summarize the major clinical trials concerning postmenopausal hormone therapy (HT), comparing their outcomes with respect to cardiovascular and neurological disease and discussing their relevance to the critical period hypothesis. Finally, potential caveats, controversies and future directions for the field are highlighted and discussed throughout the review.
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Affiliation(s)
- Erin Scott
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, GA 30912, USA
| | - Quan-guang Zhang
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, GA 30912, USA
| | - Ruimin Wang
- Experimental and Research Center, Hebei United University, 57 South Jian-she Road, Tangshan, Hebei, 063600, PR China
| | - Ratna Vadlamudi
- Department of Obstetrics & Gynecology, University of Texas Health Science Center at San Antonio, Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Darrell Brann
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, GA 30912, USA
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23
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Azcoitia I, Arevalo MA, De Nicola AF, Garcia-Segura LM. Neuroprotective actions of estradiol revisited. Trends Endocrinol Metab 2011; 22:467-73. [PMID: 21889354 DOI: 10.1016/j.tem.2011.08.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/19/2011] [Accepted: 08/03/2011] [Indexed: 12/31/2022]
Abstract
Results from animal experiments showing that estradiol is neuroprotective were challenged 10 years ago by findings indicating an increased risk of dementia and stroke in women over 65 years of age taking conjugated equine estrogens. Our understanding of the complex signaling of estradiol in neural cells has recently clarified the causes of this discrepancy. New data indicate that estradiol may lose its neuroprotective activity or even increase neural damage, a situation that depends on the duration of ovarian hormone deprivation and on age-associated modifications in the levels of other molecules that modulate estradiol action. These studies highlight the complex neuroprotective mechanisms of estradiol and suggest a window of opportunity during which effective hormonal therapy could promote brain function and cognition.
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Affiliation(s)
- Iñigo Azcoitia
- Cell Biology, Faculty of Biology, Complutense University of Madrid, E-28040 Madrid, Spain
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Clarkson TB, Utian WH, Barnes S, Gold EB, Basaria SS, Aso T, Kronenberg F, Frankenfeld CL, Cline JM, Landgren BM, Gallagher JC, Weaver CM, Hodis HN, Brinton RD, Maki PM. The role of soy isoflavones in menopausal health: report of The North American Menopause Society/Wulf H. Utian Translational Science Symposium in Chicago, IL (October 2010). Menopause 2011; 18:732-53. [PMID: 21685820 DOI: 10.1097/gme.0b013e31821fc8e0] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES If and to what extent soy protein, soy isoflavones, and their metabolites, including S(--)-equol, have beneficial effects on women's health is currently unclear. The North American Menopause Society (NAMS)/Utian Translational Science Symposium on Soy and Soy Isoflavones convened October 9-10, 2010, to clarify basic and clinical research findings as they relate to the risk and benefits of soy products for peri- and postmenopausal women. METHODS A working group of faculty and panelists composed of clinical and research experts in the fields of women's health and botanicals met during a 2-day translational symposium to cover the latest evidence-based science on isoflavones as they affect menopausal symptoms, breast and endometrial cancer, atherosclerosis, bone loss, and cognition. Full descriptions of the bioavailability and pharmacokinetics of isoflavones were also presented. Subspecialty groups then broke off with the goal of translating the information into a report for general medical practice and identifying further research areas. All faculty and panelists reviewed the final report, which was then approved by the NAMS Board of Trustees. RESULTS From the hundreds of studies reviewed in this report, there are mixed results of the effects on midlife women. Soy-based isoflavones are modestly effective in relieving menopausal symptoms; supplements providing higher proportions of genistein or increased in S(--)-equol may provide more benefits. Soy food consumption is associated with lower risk of breast and endometrial cancer in observational studies. The efficacy of isoflavones on bone has not been proven, and the clinical picture of whether soy has cardiovascular benefits is still evolving. Preliminary findings on cognitive benefit from isoflavone therapy support a "critical window" hypothesis wherein younger postmenopausal women derive more than older women. CONCLUSIONS Several areas for further research have been identified on soy and midlife women. More clinical studies are needed that compare outcomes among women whose intestinal bacteria have the ability to convert daidzein to equol (equol producers) with those that lack that ability (equol nonproducers) in order to determine if equol producers derive greater benefits from soy supplementation. Larger studies are needed in younger postmenopausal women, and more research is needed to understand the modes of use of soy isoflavone supplements in women. The interrelations of other dietary components on soy isoflavones consumed as a part of diet or by supplement on equol production also require further study, as do potential interactions with prescription and over-the-counter medications. And finally, greater standardization and documentation of clinical trial data of soy are needed.
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