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Seidel K, Kirsch S, Lucht K, Zaade D, Reinemund J, Schmitz J, Klare S, Li Y, Schefe JH, Schmerbach K, Goldin-Lang P, Zollmann FS, Thöne-Reineke C, Unger T, Funke-Kaiser H. The promyelocytic leukemia zinc finger (PLZF) protein exerts neuroprotective effects in neuronal cells and is dysregulated in experimental stroke. Brain Pathol 2011; 21:31-43. [PMID: 20731660 DOI: 10.1111/j.1750-3639.2010.00427.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Stroke is one of the major medical burdens in industrialized countries. Animal experiments indicate that blockade of the angiotensin AT1 receptor (AT1R) improves neurological outcome after cerebral ischemia. These protective effects are partially mediated by the angiotensin AT2 receptor (AT2R). The transcription factor promyelocytic leukemia zinc finger (PLZF) was identified as a direct adapter protein of the AT2R. Furthermore, our group was able to demonstrate that PLZF also directly binds and mediates the effects of the human (pro)renin receptor [(P)RR] which is involved in brain development. Therefore, we hypothesized that PLZF is involved in neuroprotection. Here we show that PLZF and its receptors (P)RR and AT2R exhibited an ubiquitous expression pattern in different brain regions. Furthermore, stable PLZF overexpression in human neuronal cells was able to mediate neuroprotection in a glutamate toxicity model in vitro. Consistently, PLZF mRNA and protein were downregulated on the ipsilateral side in a stroke model in vivo, whereas the neurodetrimental PLZF target genes cyclin A2 and BID were upregulated under this condition. Further analyses indicated that the neuroprotective AT2R is upregulated upon stable PLZF overexpression in cultured neuronal cells. Finally, reporter gene assays demonstrated the functionality of (P)RR promoter polymorphisms regarding basal and PLZF-induced activity.
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Affiliation(s)
- Kerstin Seidel
- Center for Cardiovascular Research (CCR)/ Institute of Pharmacology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Genetic variant of BDNF (Val66Met) polymorphism attenuates stroke-induced angiogenic responses by enhancing anti-angiogenic mediator CD36 expression. J Neurosci 2011; 31:775-83. [PMID: 21228186 DOI: 10.1523/jneurosci.4547-10.2011] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) has been shown to be necessary and sufficient for post-stroke recovery in rodents. From these observations, we and others have hypothesized that a common single nucleotide polymorphism (SNP) in the pro-domain of bdnf that leads to a methionine (Met) substitution for valine (Val) at codon 66 (Val66Met) will affect stroke outcome. Here we investigate the effect of the BDNF genetic variant on ischemic outcome by using mice with a genetic knock-in of the human BDNF variant in both alleles (BDNF(Met/Met)). Compared with wild-type mice, BDNF(Met/Met) mice exhibited reduced CNS BDNF levels without a discernable effect on infarct size. Diminished BDNF levels in BDNF(Met/Met) mice were associated with greater deficits in post-stroke locomotor functions. Additionally, the BDNF(Met/Met) mice showed reduced angiogenesis and elevated expression of thrombospondin-1 (TSP-1) and its receptor CD36, anti-angiogenic factors. To assess the functional role of CD36 in antagonizing angiogenic response in Met homozygosity at the BDNF locus, we crossed BDNF(Met/Met) mice with CD36 knock-out mice. The double-mutant mice rescued the angiogenic deficit associated with the BDNF(Met/Met) mice without alterations in BDNF levels, indicating that the behavioral deficit in BDNF(Met/Met) mice after stroke is partly related to an unfavorable balance in pro-angiogenic BDNF and anti-angiogenic TSP-1/CD36. The results suggest that CD36 inhibition may be a viable strategy to enhance angiogenesis and possible recovery in human stroke victims who are Met homozygotes at codon 66 of the BDNF locus.
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Abstract
SummaryLonger lifespans have been accompanied by an increasing number of older people suffering from impaired cognitive function (dementia) including Alzheimer's disease (AD) and vascular dementia (VaD). Some studies have suggested that hypertension in old age correlates with the pathogenesis of dementia. Since hypertension is potentially reversible, a number of randomized trials have examined whether antihypertensive treatment may help to prevent dementia. We review five studies, all using subjects aged 60 years or older, which investigated different antihypertensive pharmacological treatments and found conflicting results regarding impact on dementia. At the same time, other studies have suggested that hypotension in older people, especially those with low diastolic blood pressure, are also at higher risk for developing dementia. Four studies are reviewed here, but none is able to determine unequivocally if hypotension is a cause or a consequence of dementia in old age.
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Shoja MM, Agutter PS, Tubbs RS, Payner TD, Ghabili K, Cohen-Gadol AA. The role of the renin—angiotensin system in the pathogenesis of intracranial aneurysms. J Renin Angiotensin Aldosterone Syst 2011; 12:262-73. [DOI: 10.1177/1470320310387845] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Introduction: Recent work has begun to elucidate the pathogenesis of intracranial aneurysms (IA) and has shown that many genes are involved in the risk for this condition. There has also been increasing research interest in the renin—angiotensin system (RAS) in the brain and its involvement in a range of cardiovascular and neurological disorders. The possibility that the RAS is implicated in the pathogenesis of IA merits further investigation. The aim of this article is to review the literature on the pathogenesis of IA and the pathophysiological significance of the brain RAS, and to identify directions for research into their association. Methods and results : A survey of the literature in these fields shows that although factors contributing to systemic hypertension predispose to IA, a large number of genes involved in endothelial cell adhesion, smooth muscle activity, extracellular matrix dynamics and the inflammatory and immune responses are also implicated. The brain RAS has a significant role in regulating blood pressure and in maintaining cerebrovascular autoregulation, but angiotensin II receptors are also involved in the maintenance of endothelial cell and vascular smooth muscle function and in the inflammatory response in the brain. Conclusions: There is strong, albeit largely circumstantial, evidence in the literature for a relationship between the brain RAS and the formation of IA. Research on the association between polymorphisms in RAS-related genes and the incidence of unruptured and ruptured IA is indicated.
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Affiliation(s)
- Mohammadali M Shoja
- Tuberculosis and Lung Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Paul S Agutter
- Theoretical Medicine and Biology Group, Glossop, Derbyshire, UK
| | - R Shane Tubbs
- Section of Pediatric Neurosurgery, Children's Hospital, Birmingham, Alabama, USA
| | - Troy D Payner
- Clarian Neuroscience Institute, Indianapolis Neurosurgical Group and Indiana University Department of Neurosurgery, Indianapolis, USA
| | - Kamyar Ghabili
- Tuberculosis and Lung Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Aaron A Cohen-Gadol
- Clarian Neuroscience Institute, Indianapolis Neurosurgical Group and Indiana University Department of Neurosurgery, Indianapolis, USA,
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Schmerbach K, Pfab T, Zhao Y, Culman J, Mueller S, Villringer A, Muller DN, Hocher B, Unger T, Thoene-Reineke C. Effects of aliskiren on stroke in rats expressing human renin and angiotensinogen genes. PLoS One 2010; 5:e15052. [PMID: 21124781 PMCID: PMC2993950 DOI: 10.1371/journal.pone.0015052] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 10/14/2010] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Pre-treatment with angiotensin receptor blockers is known to improve neurological outcome after stroke. This study investigated for the first time, whether the renin inhibitor aliskiren has similar neuroprotective effects. METHODS Since aliskiren specifically blocks human renin, double transgenic rats expressing human renin and angiotensinogen genes were used. To achieve a systolic blood pressure of 150 or 130 mmHg animals were treated with aliskiren (7.5 or 12.5 mg/kg*d) or candesartan (1.5 or 10 mg/kg*d) via osmotic minipump starting five days before middle cerebral artery occlusion with reperfusion. Infarct size was determined by magnetic resonance imaging. mRNA of inflammatory marker genes was studied in different brain regions. RESULTS The mortality of 33.3% (7 of 21 animals) in the vehicle group was reduced to below 10% by treatment with candesartan or aliskiren (p<0.05). Aliskiren-treated animals had a better neurological outcome 7 days post-ischemia, compared to candesartan (Garcia scale: 9.9±0.7 vs. 7.3±0.7; p<0.05). The reduction of infarct size in the aliskiren group did not reach statistical significance compared to candesartan and vehicle (24 h post-ischemia: 314±81 vs. 377±70 and 403±70 mm(3) respectively). Only aliskiren was able to significantly reduce stroke-induced gene expression of CXC chemokine ligand 1, interleukin-6 and tumor necrosis factor-alpha in the ischemic core. CONCLUSIONS Head-to-head comparison suggests that treatment with aliskiren before and during cerebral ischemia is at least as effective as candesartan in double transgenic rats. The improved neurological outcome in the aliskiren group was blood pressure independent. Whether this effect is due to primary anti-inflammatory mechanisms has to be investigated further.
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Affiliation(s)
- Kristin Schmerbach
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
| | - Thiemo Pfab
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
- Department of Nephrology, Charité Campus Benjamin Franklin, Berlin, Germany
| | - Yi Zhao
- Institute of Experimental and Clinical Pharmacology, University Hospital of Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Juraj Culman
- Institute of Experimental and Clinical Pharmacology, University Hospital of Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | | | - Arno Villringer
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | | | - Berthold Hocher
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
- Institute of Nutritional Science, University of Potsdam, Potsdam, Germany
| | - Thomas Unger
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
| | - Christa Thoene-Reineke
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
- Department of Experimental Medicine (FEM), Charité, Berlin, Germany
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Renin-angiotensin system blockade and cognitive function in patients at high risk of cardiovascular disease: analysis of data from the ONTARGET and TRANSCEND studies. Lancet Neurol 2010; 10:43-53. [PMID: 20980201 DOI: 10.1016/s1474-4422(10)70250-7] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND cardiovascular risk factors are associated with dementia and cognitive decline. We investigated the effects of renin-angiotensin system blockade on cognitive function in patients aged 55 years and older with established atherosclerotic cardiovascular disease or diabetes with end-organ damage in two clinical trials. METHODS in the main study, ONTARGET, a double-blind, double-dummy, randomised controlled trial, the effects on cardiovascular outcomes of standard doses of an angiotensin-converting enzyme (ACE) inhibitor (ramipril), an angiotensin-receptor blocker (telmisartan), and a combination of the drugs were evaluated in 25 620 participants. In the parallel TRANSCEND trial, the effects of telmisartan were compared with those of placebo in 5926 participants intolerant to ACE inhibitors. Secondary outcomes included cognitive impairment (defined by investigator-reported diagnosis of dementia or significant cognitive dysfunction, or a score of ≤ 23 on the Mini-Mental State Examination [MMSE]) and cognitive decline (a decrease of ≤ 3 points on the MMSE from baseline during follow-up). Analyses were by intention to treat. We pooled data from these studies to identify baseline predictors of cognitive impairment and its frequency according to mean systolic blood pressure during follow-up. These studies were registered with ClinicalTrials.gov, number NCT00153101. FINDINGS During a median duration of 56 months (IQR 51-64) of follow-up in ONTARGET, cognitive impairment occurred in 652 (8%) of 7865 patients allocated ramipril, 584 (7%) of 7797 allocated telmisartan, and 618 (8%) of 7807 allocated combination treatment (combination vs ramipril, odds ratio [OR] 0·95, 95% CI 0·85-1·07, p= 0·39; telmisartan vs ramipril, OR 0·90, 0·80-1·01, p = 0·06). Corresponding figures for cognitive decline were 1314 (17%), 1279 (17%), and 1240 (17%) in each of the groups, respectively (telmisartan vs ramipril, OR 0·97, 0·89-1·06, p= 0·53; combination vs ramipril, OR 0·95, 0·88-1·04, p=0·28). In TRANSCEND, cognitive impairment occurred in 239 (9%) of 2694 participants allocated telmisartan compared with 245 (9%) of 2689 allocated placebo (OR 0·97, 0·81-1·17, p= 0·76). The corresponding figures for cognitive decline were 454 (17%) and 412 (16%; OR 1·10, 0·95-1·27, p= 0·22). INTERPRETATION In patients with cardiovascular disease or diabetes, different approaches to blocking of the renin-angiotensin system had no clear effects on cognitive outcomes. Although patients with the lowest systolic blood pressure had the greatest preservation of cognitive function, meta-regression analyses did not show any benefits of blood-pressure lowering on cognition over several years of treatment.
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Chan SHH, Wu CWJ, Chang AYW, Hsu KS, Chan JYH. Transcriptional upregulation of brain-derived neurotrophic factor in rostral ventrolateral medulla by angiotensin II: significance in superoxide homeostasis and neural regulation of arterial pressure. Circ Res 2010; 107:1127-39. [PMID: 20814019 DOI: 10.1161/circresaha.110.225573] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RATIONALE Oxidative stress in rostral ventrolateral medulla (RVLM), where sympathetic premotor neurons for the maintenance of neurogenic vasomotor tone are located, contributes to neural mechanisms of hypertension. Emerging evidence suggests that brain-derived neurotrophic factor (BDNF) manifests "nontrophic" actions. OBJECTIVE We assessed the hypothesis that BDNF plays an active role in oxidative stress-associated neurogenic hypertension by maintaining superoxide anion (O⁻(.)₂) homeostasis in RVLM. METHODS AND RESULTS In Wistar-Kyoto rats, microinjection of angiotensin II (Ang II) bilaterally into RVLM upregulated BDNF mRNA and protein and induced cAMP response element binding protein (CREB) phosphorylation. The Ang II-induced BDNF upregulation in RVLM was attenuated by coadministration of the NADPH oxidase inhibitor apocynin; the superoxide dismutase mimetic tempol; or an antisense oligonucleotide against CREB. Intracisternal infusion of Ang II elicited phosphorylation of p47(phox) subunit of NADPH oxidase, suppression of mitochondrial electron coupling capacity, and augmentation in mitochondrial uncoupling protein (UCP)2 expression in RVLM. The former 2 cellular events were enhanced, whereas UCP2 upregulation was attenuated by gene knockdown of BDNF or depletion of tropomyosin receptor kinase (Trk)B ligands with recombinant human TrkB-Fc fusion protein. The same treatments also significantly potentiated both Ang II-induced (O⁻(.)₂) production in RVLM and chronic pressor response. CONCLUSIONS Ang II induces (O⁻(.)₂) -dependent upregulation of BDNF in RVLM via phosphorylation of CREB. The Ang II-activated BDNF/TrkB signaling, in turn, exerts negative-feedback regulation on tissue (O⁻(.)₂) level in RVLM through inhibition of p47(phox) phosphorylation, preservation of mitochondrial electron transport capacity, and upregulation of mitochondrial UCP2, resulting in protection against Ang II-induced oxidative stress and long-term pressor response.
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Affiliation(s)
- Samuel H H Chan
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Taiwan 813, Republic of China
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58
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Talbert RL. Role of antihypertensive therapy with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers in combination with calcium channel blockers for stroke prevention. J Am Pharm Assoc (2003) 2010; 50:e116-25. [DOI: 10.1331/japha.2010.09234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Porritt MJ, Chen M, Rewell SSJ, Dean RG, Burrell LM, Howells DW. ACE inhibition reduces infarction in normotensive but not hypertensive rats: correlation with cortical ACE activity. J Cereb Blood Flow Metab 2010; 30:1520-6. [PMID: 20407464 PMCID: PMC2949242 DOI: 10.1038/jcbfm.2010.57] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Angiotensin-converting enzyme (ACE) inhibition can reduce stroke risk by up to 43% in humans and reduce the associated disability, and hence understanding the mechanism of improvement is important. In animals and humans, these effects may be independent of the blood pressure-lowering effects of ACE inhibition. Normotensive (Wistar-Kyoto (WKY)) and hypertensive (spontaneously hypertensive rat (SHR)) animals were treated with the ACE inhibitors ramipril or lisinopril for 7 or 42 days before 2 hours of transient middle cerebral artery occlusion (MCAo). Blood pressure, serum ACE, and blood glucose levels were measured and stroke infarct volume was recorded 24 hours after stroke. Despite greater reductions in blood pressure, infarct size was not improved by ACE inhibition in hypertensive animals. Short-term ACE inhibition produced only a modest reduction in blood pressure, but WKY rats showed marked reductions in infarct volume. Long-term ACE inhibition had additional reductions in blood pressure; however, infarct volumes in WKY rats did not improve further but worsened. WKY rats differed from SHR in having marked cortical ACE activity that was highly sensitive to ACE inhibition. The beneficial effects of ACE inhibition on infarct volume in normotensive rats do not correlate with changes in blood pressure. However, WKY rats have ACE inhibitor-sensitive cortical ACE activity that is lacking in the SHR.
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Affiliation(s)
- Michelle J Porritt
- Department of Medicine, University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
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Villarroel M, Ciudin A, Hernández C, Simó R. Neurodegeneration: An early event of diabetic retinopathy. World J Diabetes 2010; 1:57-64. [PMID: 21537428 PMCID: PMC3083883 DOI: 10.4239/wjd.v1.i2.57] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 03/03/2010] [Accepted: 03/10/2010] [Indexed: 02/05/2023] Open
Abstract
Diabetic retinopathy (DR) has been classically considered to be a microcirculatory disease of the retina caused by the deleterious metabolic effects of hyperglycemia per se and the metabolic pathways triggered by hyperglycemia. However, retinal neurodegeneration is already present before any microcirculatory abnormalities can be detected in ophthalmoscopic examination. In other words, retinal neurodegeneration is an early event in the pathogenesis of DR which predates and participates in the microcirculatory abnormalities that occur in DR. Therefore, the study of the mechanisms that lead to neurodegeneration will be essential to identify new therapeutic targets in the early stages of DR. Elevated levels of glutamate and the overexpression of the renin- angiotensin-system play an essential role in the neurodegenerative process that occurs in diabetic retina. Among neuroprotective factors, pigment epithelial derived factor, somatostatin and erythropoietin seem to be the most relevant and these will be considered in this review. Nevertheless, it should be noted that the balance between neurotoxic and neuroprotective factors rather than levels of neurotoxic factors alone will determine the presence or absence of retinal neurodegeneration in the diabetic eye. New strategies, based on either the delivery of neuroprotective agents or the blockade of neurotoxic factors, are currently being tested in experimental models and in clinical pilot studies. Whether these novel therapies will eventually supplement or prevent the need for laser photocoagulation or vitrectomy awaits the results of additional clinical research.
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Affiliation(s)
- Marta Villarroel
- Marta Villarroel, Andreea Ciudin, Cristina Hernández, Rafael Simó, Diabetes and Metabolism Research Unit. Institut de Recerca Hospital Universitari Vall D'Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain
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61
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Szekeres M, Nádasy GL, Turu G, Süpeki K, Szidonya L, Buday L, Chaplin T, Clark AJL, Hunyady L. Angiotensin II-induced expression of brain-derived neurotrophic factor in human and rat adrenocortical cells. Endocrinology 2010; 151:1695-703. [PMID: 20181798 DOI: 10.1210/en.2009-1060] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Angiotensin II (Ang II) is a major regulator of steroidogenesis in adrenocortical cells, and is also an effective inducer of cytokine and growth factor synthesis in several cell types. In microarray analysis of H295R human adrenocortical cells, the mRNA of brain-derived neurotrophic factor (BDNF), a neurotrophin widely expressed in the nervous system, was one of the most up-regulated genes by Ang II. The aim of the present study was the analysis of the Ang II-induced BDNF expression and BDNF-induced effects in adrenocortical cells. Real-time PCR studies have shown that BDNF is expressed in H295R and rat adrenal glomerulosa cells. In H295R cells, the kinetics of Ang II-induced BDNF expression was faster than that of aldosterone synthase (CYP11B2). Inhibition of calmodulin kinase by KN93 did not significantly affect the Ang II-induced stimulation of BDNF expression, suggesting that it occurs by a different mechanism from the CYP11B2-response. Ang II also caused candesartan-sensitive, type-1 Ang II receptor-mediated stimulation of BDNF gene expression in primary rat glomerulosa cells. In rat adrenal cortex, BDNF protein was localized to the subcapsular region. Ang II increased BDNF protein levels both in human and rat cells, and BDNF secretion of H295R cells. Ang II also increased type-1 Ang II receptor-mediated BDNF expression in vivo in furosemide-treated rats. In rat glomerulosa cells, BDNF induced tropomyosin-related kinase B receptor-mediated stimulation of EGR1 and TrkB expression. These data demonstrate that Ang II stimulates BDNF expression in human and rat adrenocortical cells, and BDNF may have a local regulatory function in adrenal glomerulosa cells.
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MESH Headings
- Adrenal Cortex/cytology
- Adrenal Cortex/drug effects
- Adrenal Cortex/metabolism
- Analysis of Variance
- Angiotensin II/pharmacology
- Animals
- Brain-Derived Neurotrophic Factor/genetics
- Brain-Derived Neurotrophic Factor/metabolism
- Calcium-Calmodulin-Dependent Protein Kinases/genetics
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Cell Line
- Cells, Cultured
- Cytochrome P-450 CYP11B2/genetics
- Cytochrome P-450 CYP11B2/metabolism
- Dose-Response Relationship, Drug
- Gene Expression/genetics
- Humans
- Immunoassay
- Immunohistochemistry
- Male
- Microscopy, Confocal
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Tissue Array Analysis
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Verdecchia P, Angeli F, Mazzotta G, Ambrosio G, Reboldi G. Angiotensin receptor blockers in hypertension. New insights from Japan. Hypertens Res 2010; 33:394-7. [PMID: 20150909 DOI: 10.1038/hr.2010.13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Angiotensin II receptor blockers (ARBs) are widely used in the treatment of patients with hypertension, heart failure, diabetic nephropathy and other clinical conditions. Several intervention trials and systematic overviews showed that both angiotensin-converting enzyme inhibitors and ARBs effectively reduce the risk of stroke, myocardial infarction and congestive heart failure in hypertensive patients. Two recent intervention trials conducted in Japan (JIKEI and Kyoto studies) suggested that the protective effect of ARBs on major cardiovascular events might be partly independent from the degree of blood pressure (BP) reduction. Both studies used a prospective randomized open blinded end point (PROBE) design. No significant differences emerged in both studies between the ARB group (valsartan) and the control group in the achieved BP. We made a pooled analysis of the JIKEI and Kyoto studies. Overall, valsartan significantly reduced the risk of the primary composite outcome (by 42%; P<0.0001), angina pectoris (by 38%; P<0.0001), heart failure requiring hospitalization (by 43%; P=0.013) and cerebrovascular events (by 42%; P=0.002). The protective effect on the dissecting aneurysm of aorta bordered statistical significance. These data reinforce the notion that the protective effect of angiotensin II inhibition is partly independent of BP reduction.
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Affiliation(s)
- Paolo Verdecchia
- Struttura Complessa di Cardiologia, Unità di Ricerca Clinica Cardiologia Preventiva, Ospedale S Maria della Misericordia, Perugia, Italy.
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Li NC, Lee A, Whitmer RA, Kivipelto M, Lawler E, Kazis LE, Wolozin B. Use of angiotensin receptor blockers and risk of dementia in a predominantly male population: prospective cohort analysis. BMJ 2010; 340:b5465. [PMID: 20068258 PMCID: PMC2806632 DOI: 10.1136/bmj.b5465] [Citation(s) in RCA: 331] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE To investigate whether angiotensin receptor blockers protect against Alzheimer's disease and dementia or reduce the progression of both diseases. DESIGN Prospective cohort analysis. SETTING Administrative database of the US Veteran Affairs, 2002-6. Population 819 491 predominantly male participants (98%) aged 65 or more with cardiovascular disease. MAIN OUTCOME MEASURES Time to incident Alzheimer's disease or dementia in three cohorts (angiotensin receptor blockers, lisinopril, and other cardiovascular drugs, the "cardiovascular comparator") over a four year period (fiscal years 2003-6) using Cox proportional hazard models with adjustments for age, diabetes, stroke, and cardiovascular disease. Disease progression was the time to admission to a nursing home or death among participants with pre-existing Alzheimer's disease or dementia. RESULTS Hazard rates for incident dementia in the angiotensin receptor blocker group were 0.76 (95% confidence interval 0.69 to 0.84) compared with the cardiovascular comparator and 0.81 (0.73 to 0.90) compared with the lisinopril group. Compared with the cardiovascular comparator, angiotensin receptor blockers in patients with pre-existing Alzheimer's disease were associated with a significantly lower risk of admission to a nursing home (0.51, 0.36 to 0.72) and death (0.83, 0.71 to 0.97). Angiotensin receptor blockers exhibited a dose-response as well as additive effects in combination with angiotensin converting enzyme inhibitors. This combination compared with angiotensin converting enzyme inhibitors alone was associated with a reduced risk of incident dementia (0.54, 0.51 to 0.57) and admission to a nursing home (0.33, 0.22 to 0.49). Minor differences were shown in mean systolic and diastolic blood pressures between the groups. Similar results were observed for Alzheimer's disease. CONCLUSIONS Angiotensin receptor blockers are associated with a significant reduction in the incidence and progression of Alzheimer's disease and dementia compared with angiotensin converting enzyme inhibitors or other cardiovascular drugs in a predominantly male population.
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Affiliation(s)
- Nien-Chen Li
- Center for the Assessment of Pharmaceutical Practices and Pharmaceutical Assessment, Management and Policy Program, Department of Health Policy and Management, Boston University School of Public Health, Boston, MA 02118-2526, USA
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Sex-different effect of angiotensin II type 2 receptor on ischemic brain injury and cognitive function. Brain Res 2009; 1300:14-23. [PMID: 19729000 DOI: 10.1016/j.brainres.2009.08.068] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 07/17/2009] [Accepted: 08/21/2009] [Indexed: 11/23/2022]
Abstract
We previously reported that angiotensin II type 2 (AT(2)) receptor signaling prevents neural damage and cognitive impairment after focal cerebral ischemia. We investigated the possible roles of the AT(2) receptor in the sex difference, focusing on cognitive function and ischemic brain damage using AT(2) receptor-deficient mice (Agtr2(-)). In Agtr2(-), spatial memory evaluated by the Morris water maze test was impaired in female compared with that in male Agtr2(-) and female wild-type (Agtr2(+)), while no significant sex-different change was observed in Agtr2(+). Interestingly, bromodeoxyuridine incorporation assay showed a significant decrease of hippocampal neurogenesis in female Agtr2(-) compared with that in female Agtr2(+). In contrast, ischemic area after middle cerebral artery (MCA) occlusion was significantly increased in male compared with female mice in Agtr2(-), while no significant sex-different change was observed in Agtr2(+). Male Agtr2(-) mice showed higher AT(1) receptor expression and significantly impaired cerebral blood flow (CBF) in the ipsilateral side 24 hours after MCA occlusion compared with female Agtr2(-) mice. In conclusion, deletion of the AT(2) receptor showed a sex-different effect such as a severe cognitive impairment with a decrease of hippocampal neurogenesis in females and a larger ischemic brain damage with a decrease of CBF in males.
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Affiliation(s)
- Rafael Simó
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud CarlosIII, Madrid, Spain.
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Mecca AP, O'Connor TE, Katovich MJ, Sumners C. Candesartan pretreatment is cerebroprotective in a rat model of endothelin-1-induced middle cerebral artery occlusion. Exp Physiol 2009; 94:937-46. [PMID: 19429641 DOI: 10.1113/expphysiol.2009.047936] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Endogenous levels of angiotensin II (Ang II) are increased in the cortex and hypothalamus following stroke, and Ang II type 1 receptor blockers (ARBs) have been shown to attenuate the deleterious effects in animal stroke models using middle cerebral artery (MCA) intraluminal occlusion procedures. However, the endothelin-1 (ET-1)-induced middle cerebral artery occlusion (MCAO) model of cerebral ischaemia is thought to more closely mimic the temporal events of an embolic stroke. This method provides rapid occlusion of the MCA and a gradual reperfusion that lasts for 16-22 h. The aim of the present study was to evaluate whether systemic administration of an ARB prior to ET-1-induced MCAO would provide cerebroprotection during this model of ischaemic stroke. Injection of 3 microl of 80 microM ET-1 adjacent to the MCA resulted in complete occlusion of the vessel that resolved over a period of 30-40 min. Following ET-1-inducedMCAO, rats had significant neurological impairment, as well as an infarct that consisted of 30% of the ipsilateral grey matter. Systemic pretreatment with 0.2 mg kg(-1) day(-1) candesartan for 7 days attenuated both the infarct size and the neurological deficits caused by ET-1-induced MCAO without altering blood pressure. This study confirms the cerebroprotective properties of ARBs during ischaemic stroke and validates the ET-1-induced MCAO model for examination of the role of the brain renin-angiotensin system in ischaemic stroke.
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Affiliation(s)
- Adam P Mecca
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA
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Abstract
Ischemic stroke causes brain damage by multiple pathways. Previous stroke trials have demonstrated that drugs targeting one or only a few of these pathways fail to improve clinical outcome after stroke. Drugs with multimodal actions have been suggested to overcome this challenge. In this review, we describe the mechanisms of action of agents approved for secondary prevention of ischemic stroke, such as antiplatelet, antihypertensive, and lipid-lowering drugs. These drugs exhibit considerable properties beyond their classical mechanisms, including neuroprotective and neuroregenerative properties. In addition, candidate stroke drugs currently studied in clinical phase III trials are described. Among these, albumin, hematopoietic growth factors, and citicoline have been identified as promising agents with multiple mechanisms. These drugs offer hope that additional treatment options for the acute phase after a stroke will become available in the near future.
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Affiliation(s)
- Jens Minnerup
- grid.5949.10000000121729288Department of Neurology, University of Münster, Albert-Schweitzer-Straβe 33, 48149 Münster, Germany
| | - Wolf-Rüdiger Schäbitz
- grid.5949.10000000121729288Department of Neurology, University of Münster, Albert-Schweitzer-Straβe 33, 48149 Münster, Germany
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Whole-body periodic acceleration reduces brain damage in a focal ischemia model. Neuroscience 2008; 158:1390-6. [PMID: 19135137 DOI: 10.1016/j.neuroscience.2008.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 11/21/2008] [Accepted: 12/03/2008] [Indexed: 02/06/2023]
Abstract
Stroke is the second most common cause of death and major cause of disability worldwide. Actual treatment involves surgery and/or thrombolytic drugs, but there is an urgent need for new approaches. Periodic acceleration, a rocking headward to footward movement of the whole body, is a non-invasive method to induce pulsatile shear stress on the vascular endothelium eliciting an enhanced production and secretion of endothelium-derived products such as nitric oxide, prostacyclin, prostaglandin E2, tissue plasminogen activator (tPA), and adrenomedullin. All these products have been shown to protect the brain from ischemic injuries. A rat model of focal brain ischemia was treated with application of periodic acceleration for 3 h immediately after the onset of ischemia. Controls remained static for the same period of time. Brain damage was assessed by magnetic resonance imaging (MRI) and biochemical markers. A significant reduction in brain damage was observed, 7 days post-ischemia, in rocked rats when compared with the static controls, through MRI. Furthermore, rocked animals had significantly lower levels of Beclin 1 and fractin than their static counterparts, and some isoforms of nitric oxide synthase were regulated by periodic acceleration. Our results show that periodic acceleration may provide a novel, affordable, non-invasive therapeutic option for the treatment of stroke.
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The β-lactam antibiotic, ceftriaxone, dramatically improves survival, increases glutamate uptake and induces neurotrophins in stroke. J Hypertens 2008; 26:2426-35. [DOI: 10.1097/hjh.0b013e328313e403] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Diener HC, Sacco RL, Yusuf S, Cotton D, Ounpuu S, Lawton WA, Palesch Y, Martin RH, Albers GW, Bath P, Bornstein N, Chan BPL, Chen ST, Cunha L, Dahlöf B, De Keyser J, Donnan GA, Estol C, Gorelick P, Gu V, Hermansson K, Hilbrich L, Kaste M, Lu C, Machnig T, Pais P, Roberts R, Skvortsova V, Teal P, Toni D, VanderMaelen C, Voigt T, Weber M, Yoon BW. Effects of aspirin plus extended-release dipyridamole versus clopidogrel and telmisartan on disability and cognitive function after recurrent stroke in patients with ischaemic stroke in the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial: a double-blind, active and placebo-controlled study. Lancet Neurol 2008; 7:875-84. [PMID: 18757238 DOI: 10.1016/s1474-4422(08)70198-4] [Citation(s) in RCA: 233] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND The treatment of ischaemic stroke with neuroprotective drugs has been unsuccessful, and whether these compounds can be used to reduce disability after recurrent stroke is unknown. The putative neuroprotective effects of antiplatelet compounds and the angiotensin II receptor antagonist telmisartan were investigated in the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial. METHODS Patients who had had an ischaemic stroke were randomly assigned in a two by two factorial design to receive either 25 mg aspirin (ASA) and 200 mg extended-release dipyridamole (ER-DP) twice a day or 75 mg clopidogrel once a day, and either 80 mg telmisartan or placebo once per day. The predefined endpoints for this substudy were disability after a recurrent stroke, assessed with the modified Rankin scale (mRS) and Barthel index at 3 months, and cognitive function, assessed with the mini-mental state examination (MMSE) score at 4 weeks after randomisation and at the penultimate visit. Analysis was by intention to treat. The study was registered with ClinicalTrials.gov, number NCT00153062. FINDINGS 20,332 patients (mean age 66 years) were randomised and followed-up for a median of 2.4 years. Recurrent strokes occurred in 916 (9%) patients randomly assigned to ASA with ER-DP and 898 (9%) patients randomly assigned to clopidogrel; 880 (9%) patients randomly assigned to telmisartan and 934 (9%) patients given placebo had recurrent strokes. mRS scores were not statistically different in patients with recurrent stroke who were treated with ASA and ER-DP versus clopidogrel (p=0.38), or with telmisartan versus placebo (p=0.61). There was no significant difference in the proportion of patients with recurrent stroke with a good outcome, as measured with the Barthel index, across all treatment groups. Additionally, there was no significant difference in the median MMSE scores, the percentage of patients with an MMSE score of 24 points or less, the percentage of patients with a drop in MMSE score of 3 points or more between 1 month and the penultimate visit, and the number of patients with dementia among the treatment groups. There were no significant differences in the proportion of patients with cognitive impairment or dementia among the treatment groups. INTERPRETATION Disability due to recurrent stroke and cognitive decline in patients with ischaemic stroke were not different between the two antiplatelet regimens and were not affected by the preventive use of telmisartan.
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Comparison between angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on the risk of myocardial infarction, stroke and death: a meta-analysis. J Hypertens 2008; 26:1282-9. [DOI: 10.1097/hjh.0b013e328306ebe2] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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