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Koyuncuoğlu T, Arabacı Tamer S, Erzik C, Karagöz A, Akakın D, Yüksel M, Yeğen BÇ. Oestrogen receptor ERα and ERβ agonists ameliorate oxidative brain injury and improve memory dysfunction in rats with an epileptic seizure. Exp Physiol 2019; 104:1911-1928. [PMID: 31608530 DOI: 10.1113/ep087986] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/08/2019] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? Could different hormonally active substances, including oestrogen receptor (ER) agonists, protect against oxidative brain damage and memory impairment induced by a single epileptic seizure in rats? If so, which signalling mechanisms are involved in their anti-inflammatory effects? What is the main finding and its importance? Chronic administration of oestrogen, progesterone, ER modulators/agonists or blockade of testosterone exhibited anti-inflammatory and antioxidant actions on single seizure-induced neuronal injury, while ER agonists additionally improved memory function and up-regulated CREB signalling and hippocampal GABA(A)α1 receptor density, suggesting that ERα or ERβ receptor activation may be beneficial in protecting against seizure-related oxidative brain injury and cognitive dysfunction. ABSTRACT The susceptibility to epileptic seizures is dependent on sex as well as fluctuations in oestrogen levels, while exogenous oestrogen was shown to have no effect or to facilitate or to inhibit seizure activity. Oestrogen receptors (ERs) mediate antioxidant and anti-inflammatory actions in several inflammatory models, but the involvement of ERs in seizure-induced neuronal injury has not been evaluated previously. In order to assess the effects of resveratrol, progesterone, oestradiol (E2), an anti-testosterone (cyproterone acetate; CPA), a selective ER modulator (tamoxifen; TMX) and ERα/ERβ agonists (propyl pyrazole triol (PPT), diarylpropionitrile (DPN)) on oxidative brain damage and memory impairment due to epileptic seizure, male Wistar rats (n = 120) received one of the treatment choices either in drinking water or intraperitoneally for 31 days, and epileptic seizure was induced on the 28th day by injection of a single-dose of pentylenetetrazole (45 mg kg-1 ). The results demonstrate that chronic pretreatment with resveratrol, progesterone, E2, CPA or TMX suppressed most of the inflammatory parameters indicative of oxidative neuronal injury, while treatment with the ER agonists DPN or PPT were found to be even more effective in limiting the oxidative damage. Treatment with DPN resulted in the up-regulation of cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) expression, while PPT up-regulated expression of CREB without affecting BDNF levels. Moreover, both ER agonists provided protection against seizure-induced memory loss with a concomitant increase in hippocampal GABA(A)α1-positive cells. In conclusion, ER agonists, and more specifically ERβ agonist, appear to provide maximum protection against seizure-induced oxidative brain injury and associated memory dysfunction by up-regulating the expression of CREB, BDNF and GABA(A)α1 receptors.
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Affiliation(s)
- Türkan Koyuncuoğlu
- Department of Physiology, School of Medicine, Marmara University, Istanbul, Turkey
| | - Sevil Arabacı Tamer
- Department of Physiology, School of Medicine, Marmara University, Istanbul, Turkey
| | - Can Erzik
- Department of Medical Biology, School of Medicine, Marmara University, Istanbul, Turkey
| | - Ayça Karagöz
- Department of Histology & Embryology, School of Medicine, Marmara University, Istanbul, Turkey
| | - Dilek Akakın
- Department of Histology & Embryology, School of Medicine, Marmara University, Istanbul, Turkey
| | - Meral Yüksel
- Department of Medical Laboratory, Vocational School of Health-Related Professions, Marmara University, Istanbul, Turkey
| | - Berrak Ç Yeğen
- Department of Physiology, School of Medicine, Marmara University, Istanbul, Turkey
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Dominguez R, Zitting M, Liu Q, Patel A, Babadjouni R, Hodis DM, Chow RH, Mack WJ. Estradiol Protects White Matter of Male C57BL6J Mice against Experimental Chronic Cerebral Hypoperfusion. J Stroke Cerebrovasc Dis 2018; 27:1743-1751. [PMID: 29602614 PMCID: PMC5972054 DOI: 10.1016/j.jstrokecerebrovasdis.2018.01.030] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 01/03/2018] [Accepted: 01/25/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Estradiol is a sex steroid hormone known to protect the brain against damage related to transient and global cerebral ischemia. In the present study, we leverage an experimental murine model of bilateral carotid artery stenosis (BCAS) to examine the putative effects of estradiol therapy on chronic cerebral hypoperfusion. We hypothesize that long-term estradiol therapy protects against white matter injury and declarative memory deficits associated with chronic cerebral hypoperfusion. METHODS Adult male C57BL/6J mice underwent either surgical BCAS or sham procedures. Two days after surgery, the mice were given oral estradiol (Sham+E, BCAS+E) or placebo (Sham+P, BCAS+P) treatments daily for 31-34 days. All mice underwent Novel Object Recognition (NOR) testing 31-34 days after the start of oral treatments. Following sacrifice, blood was collected and brains fixed, sliced, and prepared for histological examination of white matter injury and extracellular signal-regulated kinase (ERK) expression. RESULTS Animals receiving long-term oral estradiol therapy (BCAS-E2 and Sham-E2) had higher plasma estradiol levels than those receiving placebo treatment (BCAS-P and Sham-P). BCAS-E2 mice demonstrated less white matter injury (Klüver-Barrera staining) and performed better on the NOR task compared to BCAS-P mice. ERK expression in the brain was increased in the BCAS compared to sham cohorts. Among the BCAS mice, the BCAS-E2 cohort had a greater number of ERK + cells. CONCLUSION This study demonstrates a potentially protective role for oral estradiol therapy in the setting of white matter injury and declarative memory deficits secondary to murine chronic cerebral hypoperfusion.
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Affiliation(s)
- Reymundo Dominguez
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Madison Zitting
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Qinghai Liu
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Arati Patel
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Robin Babadjouni
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Drew M Hodis
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Robert H Chow
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - William J Mack
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California.
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He L, He R, Liang R, Li Y, Li X, Li C, Zhang S. Protein expression profiling in the hippocampus after focal cerebral ischemia injury in rats. J Integr Neurosci 2018. [DOI: 10.3233/jin-170047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Lichan He
- Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, No. 396 Tongfu Zhong Road, Guangzhou 510220, China. E-mail:
| | - Rui He
- Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, No. 396 Tongfu Zhong Road, Guangzhou 510220, China. E-mail:
| | - Ruihua Liang
- Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, No. 396 Tongfu Zhong Road, Guangzhou 510220, China. E-mail:
| | - Yi Li
- Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, No. 396 Tongfu Zhong Road, Guangzhou 510220, China. E-mail:
| | - Xiaoqiang Li
- Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, No. 396 Tongfu Zhong Road, Guangzhou 510220, China. E-mail:
| | - Chuqiao Li
- Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, No. 396 Tongfu Zhong Road, Guangzhou 510220, China. E-mail:
| | - Suping Zhang
- Department of Neurology, Guangzhou Red Cross Hospital, Medical College, Jinan University, No. 396 Tongfu Zhong Road, Guangzhou 510220, China. E-mail:
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Ebrahimzadeh-Bideskan AR, Mansouri S, Ataei ML, Jahanshahi M, Hosseini M. The effects of soy and tamoxifen on apoptosis in the hippocampus and dentate gyrus in a pentylenetetrazole-induced seizure model of ovariectomized rats. Anat Sci Int 2018; 93:218-230. [PMID: 28283880 DOI: 10.1007/s12565-017-0398-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 03/02/2017] [Indexed: 12/13/2022]
Abstract
The effects of tamoxifen and soy on apoptosis of the hippocampus and dentate gyrus of ovariectomized rats after repeated seizures were investigated. Female rats were divided into: (1) Control, (2) Sham, (3) Sham-Tamoxifen (Sham-T), (4) Ovariectomized (OVX), (5) OVX-Tamoxifen (OVX-T), (6)OVX-Soy(OVX-S) and (7) OVX-S-T. The animals in the OVX-S, OVX-T and OVX-S-T groups received soy extract (60 mg/kg; i.p.), tamoxifen (10 mg/kg) or both for 2 weeks before induction of seizures. The animals in these groups additionally received the mentioned treatments before each injection of pentylenetetrazole (PTZ; 40 mg/kg) for 6 days. The animals in the Sham and OVX groups received a vehicle of tamoxifen and soy. A significant decrease in the seizure score and TUNEL-positive neurons was seen in the OVX group compared to the Sham (P < 0.001). The animals in both the OVX-T and OVX-S groups had a significantly higher seizure score as well as number of TUNEL-positive neurons compared to the OVX group (P < 0.01-P < 0.001). Co-treatment of the OVX rats by the extract and tamoxifen decreased the seizure score and number of TUNEL-positive neurons compared to OVX-S (P < 0.001). Treatment of the OVX rats by either soy or tamoxifen increased the seizure score as well as the number of TUNEL-positive neurons in the hippocampal formation. Co-administration of tamoxifen and soy extract inhibited the effects of the soy extract and tamoxifen when they were administered alone. It might be suggested that both soy and tamoxifen have agonistic effects on estrogen receptors by changing the seizure severity.
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Affiliation(s)
- Ali Reza Ebrahimzadeh-Bideskan
- Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Microanatomy Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Somaieh Mansouri
- Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mariam Lale Ataei
- Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehrdad Jahanshahi
- Department of Anatomy, School of Medicine, Golestan University of Medical Sciences, Grogan, Iran
| | - Mahmoud Hosseini
- Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
- Pharmacological Research Center of Medicinal Plants, Mashhad University of Medical Sciences, Mashhad, Iran.
- Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Azadi Square, Mashhad, Iran.
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Zhong YH, Dhawan J, Kovoor JA, Sullivan J, Zhang WX, Choi D, Biegon A. Aromatase and neuroinflammation in rat focal brain ischemia. J Steroid Biochem Mol Biol 2017; 174:225-233. [PMID: 28964927 DOI: 10.1016/j.jsbmb.2017.09.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 09/24/2017] [Accepted: 09/25/2017] [Indexed: 12/22/2022]
Abstract
Accumulating evidence suggests that expression of aromatase, the enzyme responsible for the conversion of androgens to estrogens, is transiently upregulated in rat stroke models. It was further suggested that increased aromatase expression is linked to neuroinflammation and that it is neuroprotective in females. Our goal was to investigate aromatase upregulation in male rats subjected to experimental stroke in relationship to neuroinflammation, infarct and response to treatment with different putative neuroprotective agents. Intact male rats were subjected to transient (90min) middle cerebral artery occlusion (MCAO) and administered selfotel (N-methyl-d-aspartic acid (NMDA) receptor competitive antagonist), TPEN (a zinc chelator), a combination of the two drugs or vehicle, injected immediately after reperfusion. Animals were killed 14days after MCAO and consecutive brain sections used to measure aromatase expression, cerebral infarct volume and neuroinflammation. Quantitative immunohistochemistry (IHC) demonstrated increased brain aromatase expression in the peri-infarct area relative to contralesional area, which was partially abrogated by neuroprotective agents. There was no correlation between aromatase expression in the peri-infarct zone and infarct volume, which was reduced by neuroprotective agents. Microglial activation, measured by quantitative autoradiography, was positively correlated with infarct and inversely correlated with aromatase expression in the peri-infarct zone. Our findings indicate that focal ischemia upregulates brain aromatase in the male rat brain at 14days post surgery, which is within the time frame documented in females. However, the lack of negative correlation between aromatase expression and infarct volume and lack of positive correlation between microgliosis and aromatase do not support a major role for aromatase as a mediator of neuroprotection or a causal relationship between microglial activation and increased aromatase expression in male focal ischemia.
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Affiliation(s)
- Yu H Zhong
- Department of Neurology, the First Affiliated Hospital of Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, Guangdong Province 510080, PR China; Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - Jasbeer Dhawan
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - Joel A Kovoor
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - John Sullivan
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - Wei X Zhang
- Department of Neurology, the First Affiliated Hospital of Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, Guangdong Province 510080, PR China.
| | - Dennis Choi
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - Anat Biegon
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
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Gerbils exhibit stable open-arms exploration across repeated testing on the elevated plus-maze. Behav Processes 2016; 122:104-9. [DOI: 10.1016/j.beproc.2015.11.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 10/21/2015] [Accepted: 11/20/2015] [Indexed: 11/22/2022]
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The loss of estrogen efficacy against cerebral ischemia in aged postmenopausal female mice. Neurosci Lett 2014; 558:115-9. [DOI: 10.1016/j.neulet.2013.11.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 11/03/2013] [Accepted: 11/07/2013] [Indexed: 11/19/2022]
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Inagaki T, Etgen AM. Neuroprotective action of acute estrogens: animal models of brain ischemia and clinical implications. Steroids 2013; 78:597-606. [PMID: 23385013 PMCID: PMC3733348 DOI: 10.1016/j.steroids.2012.12.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 12/20/2012] [Accepted: 12/28/2012] [Indexed: 10/27/2022]
Abstract
The ovarian hormone 17β-estradiol (E2) exerts profound neuroprotective actions against ischemia-induced brain damage in rodent models of global and focal ischemia. This review focuses on the neuroprotective efficacy of post-ischemic administration of E2 and non-feminizing estrogen analogs in the aging brain, with an emphasis on studies in animals subjected to a long-term loss of circulating E2. Clinical findings from the Women's Health Initiative study as well as data from animal studies that used long-term, physiological levels of E2 treatment are discussed in this context. We summarize major published findings that highlight the effective doses and timing of E2 treatment relative to onset of ischemia. We then discuss recent findings from our laboratory showing that under some conditions the aging hippocampus remains responsive to E2 and some neuroprotective non-feminizing estrogen analogs even after prolonged periods of hormone withdrawal. Possible membrane-initiated signaling mechanisms that may underlie the neuroprotective actions of acutely administered E2 are also discussed. Based on these findings, we suggest that post-ischemic treatment with high doses of E2 or certain non-feminizing estrogen analogs may have great therapeutic potential for treatment of brain damage and neurodegeneration associated with ischemia.
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Affiliation(s)
- Tomoko Inagaki
- Dominick P. Purpura Dept. of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
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Wappler EA, Antal P, Várbíró S, Székács B, Simon A, Nagy Z, Monos E, Nádasy GL. Network remodeling of intramural coronary resistance arteries in the aged rat: a statistical analysis of geometry. Mech Ageing Dev 2013; 134:307-13. [PMID: 23523620 DOI: 10.1016/j.mad.2013.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 02/17/2013] [Accepted: 03/09/2013] [Indexed: 11/25/2022]
Abstract
AIMS To identify the geometrical alterations in the age-remodeled rat coronary artery network and to develop a useful technique to analyze network properties in the rat heart. METHODS AND RESULTS We analyzed the networks of the left anterior descendent coronary arteries on in situ perfused hearts of young (3 months) and old (18 months) male rats. All segments and branching over >80 μm diameter were analyzed using 50 μm long cylindrical ring units of the networks. Arterial widening and paucity, increased tortuosity were typical features in the old network. In addition, axis angles deviated more from the mother branches in the old, whereas the diameters of daughter branches fit the Murray law in both groups. The detected changes in the old network resulted in a longer blood flow route for the same direct distance. CONCLUSION We developed a useful method to investigate arterial network property changes in the rat heart. Ageing resulted in longer, more tortuous flow route in the LAD network that might be hemodynamically disadvantageous.
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Affiliation(s)
- Edina A Wappler
- Department of Anesthesiology and Intensive Therapy, Semmelweis University, Budapest, Hungary.
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Inagaki T, Kaneko N, Zukin RS, Castillo PE, Etgen AM. Estradiol attenuates ischemia-induced death of hippocampal neurons and enhances synaptic transmission in aged, long-term hormone-deprived female rats. PLoS One 2012; 7:e38018. [PMID: 22675505 PMCID: PMC3366987 DOI: 10.1371/journal.pone.0038018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 05/02/2012] [Indexed: 11/18/2022] Open
Abstract
Background Transient global forebrain ischemia causes selective, delayed death of hippocampal CA1 pyramidal neurons, and the ovarian hormone 17β-estradiol (E2) reduces neuronal loss in young and middle-aged females. The neuroprotective efficacy of E2 after a prolonged period of hormone deprivation is controversial, and few studies examine this issue in aged animals given E2 treatment after induction of ischemia. Methodology/Principal Findings The present study investigated the neuroprotective effects of E2 administered immediately after global ischemia in aged female rats (15–18 months) after 6 months of hormone deprivation. We also used electrophysiological methods to assess whether CA1 synapses in the aging hippocampus remain responsive to E2 after prolonged hormone withdrawal. Animals were ovariohysterectomized and underwent 10 min global ischemia 6 months later. A single dose of E2 (2.25 µg) infused intraventricularly after reperfusion significantly increased cell survival, with 45% of CA1 neurons surviving vs 15% in controls. Ischemia also induced moderate loss of CA3/CA4 pyramidal cells. Bath application of 1 nM E2 onto brain slices derived from non-ischemic aged females after 6 months of hormone withdrawal significantly enhanced excitatory transmission at CA1 synapses evoked by Schaffer collateral stimulation, and normal long-term potentiation (LTP) was induced. The magnitude of LTP and of E2 enhancement of field excitatory postsynaptic potentials was indistinguishable from that recorded in slices from young rats. Conclusions/Significance The data demonstrate that 1) acute post-ischemic infusion of E2 into the brain ventricles is neuroprotective in aged rats after 6 months of hormone deprivation; and 2) E2 enhances synaptic transmission in CA1 pyramidal neurons of aged long-term hormone deprived females. These findings provide evidence that the aging hippocampus remains responsive to E2 administered either in vivo or in vitro even after prolonged periods of hormone withdrawal.
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Affiliation(s)
- Tomoko Inagaki
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Naoki Kaneko
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - R. Suzanne Zukin
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Pablo E. Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Anne M. Etgen
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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van der Staay FJ, Gieling ET, Pinzón NE, Nordquist RE, Ohl F. The appetitively motivated “cognitive” holeboard: A family of complex spatial discrimination tasks for assessing learning and memory. Neurosci Biobehav Rev 2012; 36:379-403. [DOI: 10.1016/j.neubiorev.2011.07.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 06/30/2011] [Accepted: 07/04/2011] [Indexed: 12/27/2022]
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Leon RL, Huber JD, Rosen CL. Potential age-dependent effects of estrogen on neural injury. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2450-60. [PMID: 21641373 DOI: 10.1016/j.ajpath.2011.01.057] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 12/28/2010] [Accepted: 01/07/2011] [Indexed: 12/27/2022]
Abstract
In 2000, approximately 10 million women were receiving hormone replacement therapy (HRT) for alleviation of menopausal symptoms. A number of prior animal studies suggested that HRT may be neuroprotective and cardioprotective. Then, in 2003, reports from the Women's Health Initiative (WHI) indicated that long-term estrogen/progestin supplementation led to increased incidence of stroke. A second branch of the WHI in women with prior hysterectomy found an even stronger correlation between estrogen supplementation alone and stroke incidence. Follow-up analyses of the data, as well as data from other smaller clinical trials, have also demonstrated increased stroke severity in women receiving HRT or estrogen alone. This review examines the studies indicating that estrogen is neuroprotectant in animal models and explores potential reasons why this may not be true in postmenopausal women. Specifically, age-related differences in estrogen receptors and estrogenic actions in the brain are discussed, with the conclusion that animal models of disease must closely mimic human disease to produce clinically relevant results.
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Affiliation(s)
- Rachel L Leon
- Department of Neurosurgery, West Virginia University, Morgantown, West Virginia, USA
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Etgen AM, Jover-Mengual T, Zukin RS. Neuroprotective actions of estradiol and novel estrogen analogs in ischemia: translational implications. Front Neuroendocrinol 2011; 32:336-52. [PMID: 21163293 PMCID: PMC3080451 DOI: 10.1016/j.yfrne.2010.12.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 12/06/2010] [Accepted: 12/09/2010] [Indexed: 11/15/2022]
Abstract
This review highlights our investigations into the neuroprotective efficacy of estradiol and other estrogenic agents in a clinically relevant animal model of transient global ischemia, which causes selective, delayed death of hippocampal CA1 neurons and associated cognitive deficits. We find that estradiol rescues a significant number of CA1 pyramidal neurons that would otherwise die in response to global ischemia, and this is true when hormone is provided as a long-term pretreatment at physiological doses or as an acute treatment at the time of reperfusion. In addition to enhancing neuronal survival, both forms of estradiol treatment induce measurable cognitive benefit in young animals. Moreover, estradiol and estrogen analogs that do not bind classical nuclear estrogen receptors retain their neuroprotective efficacy in middle-aged females deprived of ovarian hormones for a prolonged duration (8weeks). Thus, non-feminizing estrogens may represent a new therapeutic approach for treating the neuronal damage associated with global ischemia.
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Affiliation(s)
- Anne M Etgen
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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Wappler E, Gál A, Skopál J, Nagy Z. Single, high-dose 17β-estradiol therapy has anti-apoptotic effect and induces cerebral plasticity following transient forebrain ischemia in gerbils (Short communication). ACTA ACUST UNITED AC 2011; 98:189-94. [DOI: 10.1556/aphysiol.98.2011.2.10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Current world literature. Curr Opin Pediatr 2011; 23:356-63. [PMID: 21566469 DOI: 10.1097/mop.0b013e3283481706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Fatehi-Hassanabad Z, Tasker RA. Peroxisome Proliferator-Activated Receptor-γ (PPAR-γ) Activation Confers Functional Neuroprotection in Global Ischemia. Neurotox Res 2010; 19:462-71. [DOI: 10.1007/s12640-010-9201-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 05/17/2010] [Accepted: 05/20/2010] [Indexed: 12/27/2022]
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Microvascular changes in estrogen-α sensitive brainstem structures of aging female hamsters. Neurosci Res 2010; 67:267-74. [PMID: 20420863 DOI: 10.1016/j.neures.2010.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 04/15/2010] [Accepted: 04/16/2010] [Indexed: 12/27/2022]
Abstract
Structural neuronal plasticity is present in the nucleus para-retroambiguus (NPRA) and the commissural nucleus of the solitary tract/A2 group (NTScom/A2) in female hamsters. Both brainstem nuclei play a role in estrous cycle related autonomic adaptations. We investigated how aging affects the capillary condition in these adaptive brainstem regions. Senescent female hamsters (+/-95 weeks) were tested weekly for their 4-day estrous cycle. Subsequently morphological changes of NPRA and NTScom/A2 were compared with those of young (+/-20 weeks) females in an ultrastructural study. The medial tegmental field served as control area. In 841 capillaries (n=319 capillaries, young females (N=3); n=522 capillaries, aged females (N=4)) vascular aberrations were classified into 3 categories: endothelial and tight junction, basement membrane and pericyte aberrations. In old animals, capillaries showed marked endothelial changes, disrupted tight junctions, and thickening and splitting of basement membranes. Aberrations were found in 40-60% of all capillaries. About 70% of the pericytes contained degenerative inclusions. Despite this generalized vascular degeneration, the reproductive cycle of female hamsters was unaffected by vascular senescence. Perivascular fibrosis as reported in aging rats was never observed, which suggests the existence of species differences.
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