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van Sloten TT, Souverein PC, Stehouwer CDA, Driessen JHM. Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers and risk of depression among older people with hypertension. J Psychopharmacol 2022; 36:594-603. [PMID: 35388727 PMCID: PMC9112619 DOI: 10.1177/02698811221082470] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), commonly used antihypertensive drugs, may have a protective effect against depression in older individuals, but evidence in humans is limited. AIMS We evaluated the risk of depression, among older individuals with hypertension, comparing ACE or ARB initiators to thiazide(-like) diuretic initiators. Thiazide(-like) diuretics were used as control because these drugs are not associated with mood disorders. METHODS We used a propensity score-matched new user cohort design with routinely collected data from general practices in England from the Clinical Practice Research Datalink database. We matched 12,938 pairs of new users of ACEIs/ARBs and thiazide(-like) diuretics with hypertension (mean age 67.6 years; 54.7% women). Follow-up time started on the date of drug initiation and ended on the date of treatment discontinuation plus 30 days, or switch to a comparator, occurrence of a study event, death, date of patient's transfer out of practice, or end of the study period. The primary outcome was a composite endpoint of treated depression and nonfatal and fatal self-harm. RESULTS/OUTCOMES Compared to the thiazide(-like) diuretic group, ACEIs/ARBs use was not associated with a lower risk of the primary outcome (hazard ratio 0.96 (95% confidence interval: 0.79; 1.15)). Results did not differ according to lipophilicity, duration of use, and average daily dose, or class (ACEIs or ARBs). CONCLUSIONS/INTERPRETATION New use of ACEIs or ARBs is not associated with a lower risk of depression among individuals with hypertension.
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Affiliation(s)
- Thomas T van Sloten
- Department of Internal Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands,School for Cardiovascular Diseases (CARIM), Maastricht University, Maastricht, The Netherlands,Thomas T van Sloten, Department of Internal Medicine, Maastricht University Medical Center+, P. Debyelaan 25, P.O. Box 5800, 6202AZ Maastricht, The Netherlands.
| | - Patrick C Souverein
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Coen DA Stehouwer
- Department of Internal Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands,School for Cardiovascular Diseases (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Johanna HM Driessen
- School for Cardiovascular Diseases (CARIM), Maastricht University, Maastricht, The Netherlands,Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands,Department of Clinical Pharmacy and Toxicology, Maastricht University Medical Center+, Maastricht, The Netherlands,School of Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University, Maastricht, The Netherlands
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Ungvari Z, Toth P, Tarantini S, Prodan CI, Sorond F, Merkely B, Csiszar A. Hypertension-induced cognitive impairment: from pathophysiology to public health. Nat Rev Nephrol 2021; 17:639-654. [PMID: 34127835 PMCID: PMC8202227 DOI: 10.1038/s41581-021-00430-6] [Citation(s) in RCA: 203] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2021] [Indexed: 02/06/2023]
Abstract
Hypertension affects two-thirds of people aged >60 years and significantly increases the risk of both vascular cognitive impairment and Alzheimer's disease. Hypertension compromises the structural and functional integrity of the cerebral microcirculation, promoting microvascular rarefaction, cerebromicrovascular endothelial dysfunction and neurovascular uncoupling, which impair cerebral blood supply. In addition, hypertension disrupts the blood-brain barrier, promoting neuroinflammation and exacerbation of amyloid pathologies. Ageing is characterized by multifaceted homeostatic dysfunction and impaired cellular stress resilience, which exacerbate the deleterious cerebromicrovascular effects of hypertension. Neuroradiological markers of hypertension-induced cerebral small vessel disease include white matter hyperintensities, lacunar infarcts and microhaemorrhages, all of which are associated with cognitive decline. Use of pharmaceutical and lifestyle interventions that reduce blood pressure, in combination with treatments that promote microvascular health, have the potential to prevent or delay the pathogenesis of vascular cognitive impairment and Alzheimer's disease in patients with hypertension.
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Affiliation(s)
- Zoltan Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Peter Toth
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Neurosurgery, Medical School, University of Pecs, Pecs, Hungary
| | - Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Calin I Prodan
- Department of Neurology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Veterans Affairs Medical Center, Oklahoma City, OK, USA
| | - Farzaneh Sorond
- Department of Neurology, Division of Stroke and Neurocritical Care, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Bela Merkely
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Institute of Clinical Experimental Research, Semmelweis University, Budapest, Hungary.
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3
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Empana JP, Boutouyrie P, Lemogne C, Jouven X, van Sloten TT. Microvascular Contribution to Late-Onset Depression: Mechanisms, Current Evidence, Association With Other Brain Diseases, and Therapeutic Perspectives. Biol Psychiatry 2021; 90:214-225. [PMID: 34325805 DOI: 10.1016/j.biopsych.2021.04.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/16/2022]
Abstract
Depression is common in older individuals and is associated with high disability and mortality. A major problem is treatment resistance: >50% of older patients do not respond to current antidepressants. Therefore, new effective interventions for prevention and treatment of depression in older individuals need to be developed, which requires a better understanding of the mechanisms underlying depression. The pathophysiology of depression is multifactorial and complex. Microvascular dysfunction may be an early and targetable mechanism in the development of depression, notably depression that initiates in late life (late-onset depression). Late-onset depression commonly co-occurs with other diseases or syndromes that may share a microvascular origin, including apathy, cognitive impairment, dementia, and stroke. Together, these disabilities may all be part of one large phenotype resulting from global cerebral microvascular dysfunction. In this review, we discuss the pathophysiology of microvascular dysfunction-related late-onset depression, summarize recent epidemiological evidence on the association between cerebral microvascular dysfunction and depression, and indicate potential drivers of cerebral microvascular dysfunction. We also propose the hypothesis that depression may be a manifestation of a larger phenotype of cerebral microvascular dysfunction, highlight potential therapeutic targets and interventions, and give directions for future research.
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Affiliation(s)
- Jean-Philippe Empana
- Université de Paris, INSERM, U970, Paris Cardiovascular Research Center, Paris, France
| | - Pierre Boutouyrie
- Université de Paris, INSERM, U970, Paris Cardiovascular Research Center, Paris, France
| | - Cédric Lemogne
- Université de Paris, AP-HP, Hôpital Hôtel-Dieu, DMU Psychiatrie et Addictologie, Service de Psychiatrie de l'adulte, INSERM, Institut de Psychiatrie et Neurosciences de Paris, UMR_S1266, Paris, France
| | - Xavier Jouven
- Université de Paris, INSERM, U970, Paris Cardiovascular Research Center, Paris, France
| | - Thomas T van Sloten
- Université de Paris, INSERM, U970, Paris Cardiovascular Research Center, Paris, France; School for Cardiovascular Diseases Maastricht and Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, the Netherlands.
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4
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Elhessy HM, Eltahry H, Erfan OS, Mahdi MR, Hazem NM, El-Shahat MA. Evaluation of the modulation of nitric oxide synthase expression in the cerebellum of diabetic albino rats and the possible protective effect of ferulic acid. Acta Histochem 2020; 122:151633. [PMID: 33045658 DOI: 10.1016/j.acthis.2020.151633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 01/29/2023]
Abstract
INTRODUCTION Diabetes mellitus is a multisystem disease. Oxidative stress and nitric oxide isoforms are involved in diabetic pathogenesis. Ferulic acid is a natural substance that is distributed broadly in plants with strong potent properties. THE AIM OF THE RESEARCH This research was designed to study the possible protective role of ferulic acid on oxidative stress and different Nitric oxide synthase isoforms (NOS) in the cerebellum of streptozotocin-induced diabetic rats. MATERIALS AND METHODS Twenty-four albino male rats were randomly divided into equal four groups: control group, group 2 received ferulic acid orally (10 mg/kg), group 3 diabetic group, group 4 diabetic rats received ferulic acid. After 8 weeks, the left cerebellar hemisphere was taken for tissue homogenate for oxidative markers and real-time PCR for NOS isoforms. Paraffin sections of the right cerebellar hemisphere were stained with cresyl violet, Luxol fast blue and immnunohistochemically stained for neuronal NOS, inducible NOS and endothelial NOS. RESULTS Degenerative changes were seen in the cerebella of the diabetic rats with significant elevation of Malondialdehyde, Nitric Oxide, and decrease of Superoxide dismutase levels. nNOS expression decreased and iNOS expression increased significantly. The ferulic acid-treated group showed a reduction of the degenerative changes in the cerebellum with significant improvement in oxidative stress marker, an increase of nNOS expression, and a decrease of iNOS expression. CONCLUSIONS Ferulic acid improves cerebellar functional and histopathological changes induced by diabetes which can be attributed mainly to its anti-oxidative effect and its ability to modulate NOS isoforms.
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van Sloten TT, Sedaghat S, Carnethon MR, Launer LJ, Stehouwer CDA. Cerebral microvascular complications of type 2 diabetes: stroke, cognitive dysfunction, and depression. Lancet Diabetes Endocrinol 2020; 8:325-336. [PMID: 32135131 DOI: 10.1016/s2213-8587(19)30405-x] [Citation(s) in RCA: 279] [Impact Index Per Article: 69.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/29/2019] [Accepted: 12/11/2019] [Indexed: 12/19/2022]
Abstract
Adults with type 2 diabetes are at an increased risk of developing certain brain or mental disorders, including stroke, dementia, and depression. Although these disorders are not usually considered classic microvascular complications of diabetes, evidence is growing that microvascular dysfunction is one of the key underlying mechanisms. Microvascular dysfunction is a widespread phenomenon in people with diabetes, including effects on the brain. Cerebral microvascular dysfunction is also apparent in adults with prediabetes, suggesting that cerebral microvascular disease processes start before the onset of diabetes. The microvasculature is involved in the regulation of many cerebral processes that when impaired predispose to lacunar and haemorrhagic stroke, cognitive dysfunction, and depression. Main drivers of diabetes-related cerebral microvascular dysfunction are hyperglycaemia, obesity and insulin resistance, and hypertension. Increasing amounts of data from observational studies suggest that diabetes-related microvascular dysfunction is associated with a higher risk of stroke, cognitive dysfunction, and depression. Cerebral outcomes in diabetes might be improved following treatments targeting the pathways through which diabetes damages the microcirculation. These treatments might include drugs that reduce dicarbonyl compounds, augment cerebral insulin signalling, or improve blood-brain barrier permeability and cerebral vasoreactivity.
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Affiliation(s)
- Thomas T van Sloten
- Department of Internal Medicine, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Sanaz Sedaghat
- Department of Preventive Medicine and Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Mercedes R Carnethon
- Department of Preventive Medicine and Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Lenore J Launer
- Laboratory of Epidemiology and Population Sciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Coen D A Stehouwer
- Department of Internal Medicine, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, Netherlands.
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6
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Fouda AY, Fagan SC, Ergul A. Brain Vasculature and Cognition. Arterioscler Thromb Vasc Biol 2019; 39:593-602. [PMID: 30816798 PMCID: PMC6540805 DOI: 10.1161/atvbaha.118.311906] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 02/15/2019] [Indexed: 12/18/2022]
Abstract
There is a complex interaction between the brain and the cerebral vasculature to meet the metabolic demands of the brain for proper function. Preservation of cerebrovascular function and integrity has a central role in this sophisticated communication within the brain, and any derangements can have deleterious acute and chronic consequences. In almost all forms of cognitive impairment, from mild to Alzheimer disease, there are changes in cerebrovascular function and structure leading to decreased cerebral blood flow, which may initiate or worsen cognitive impairment. In this focused review, we discuss the contribution of 2 major vasoactive pathways to cerebrovascular dysfunction and cognitive impairment in an effort to identify early intervention strategies.
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Affiliation(s)
- Abdelrahman Y. Fouda
- Vascular Biology Center, Augusta University, GA
- Charlie Norwood VA Medical Center Augusta, GA
| | - Susan C. Fagan
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, GA
- Charlie Norwood VA Medical Center Augusta, GA
| | - Adviye Ergul
- Ralph Johnson Veterans Administration Medical Center, Medical University of South Carolina, Charleston, SC
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC
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7
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Hardigan T, Ward R, Ergul A. Cerebrovascular complications of diabetes: focus on cognitive dysfunction. Clin Sci (Lond) 2016; 130:1807-22. [PMID: 27634842 PMCID: PMC5599301 DOI: 10.1042/cs20160397] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/11/2015] [Indexed: 01/01/2023]
Abstract
The incidence of diabetes has more than doubled in the United States in the last 30 years and the global disease rate is projected to double by 2030. Cognitive impairment has been associated with diabetes, worsening quality of life in patients. The structural and functional interaction of neurons with the surrounding vasculature is critical for proper function of the central nervous system including domains involved in learning and memory. Thus, in this review we explore cognitive impairment in patients and experimental models, focusing on links to vascular dysfunction and structural changes. Lastly, we propose a role for the innate immunity-mediated inflammation in neurovascular changes in diabetes.
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Affiliation(s)
- Trevor Hardigan
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA 30912, U.S.A
| | - Rebecca Ward
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, U.S.A
| | - Adviye Ergul
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA 30912, U.S.A. Charlie Norwood Veterans Administration Medical Center, Augusta, GA 30912, U.S.A.
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8
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Mu ZH, Jiang Z, Lin XJ, Wang LP, Xi Y, Zhang ZJ, Wang YT, Yang GY. Vessel Dilation Attenuates Endothelial Dysfunction Following Middle Cerebral Artery Occlusion in Hyperglycemic Rats. CNS Neurosci Ther 2016; 22:316-24. [PMID: 26842484 DOI: 10.1111/cns.12500] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/26/2015] [Accepted: 11/27/2015] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVES Dynamically observe cerebral vascular changes in hyperglycemic rats in vivo and explore the effect of diabetes on endothelial function after ischemic stroke. BACKGROUND Diabetes affects both large and small vessels in the brain, but the dynamic process and mechanism are unclear. METHODS We investigated the structural and functional changes of brain vasculature in living hyperglycemic rats and their impact on stroke outcomes via a novel technique: synchrotron radiation angiography. We also examined the effect of prolonged fasudil treatment on arterial reactivity and hemorrhagic transformation. Adult Sprague Dawley rats were treated by streptozotocin to induce type 1 diabetes. These hyperglycemic rats received fasudil pretreatment and then underwent transient middle cerebral artery occlusion. RESULTS We found that diabetes caused arteries narrowing in the circus Willis as early as 2 weeks after streptozotocin injection (P < 0.05). These vessels were further constricted after middle cerebral artery occlusion. L-NAME could induce regional constrictions and impaired relaxation in hyperglycemic animals. Furthermore, hemorrhagic transformation was also increased in the hyperglycemic rats compared to the control (P < 0.05). In fasudil-treated rats, the internal carotid artery narrowing was ameliorated and L-NAME-induced regional constriction was abolished. Importantly, stroke prognosis was improved in fasudil-treated rats compared to the control (P < 0.05). CONCLUSIONS Our dynamic angiographic data demonstrated that diabetes could impair the cerebral arterial reactivity. Prolonged fasudil treatment could attenuate arterial dysfunction and improve the prognosis of ischemic stroke by affecting both the large and small vasculature.
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Affiliation(s)
- Zhi-Hao Mu
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhen Jiang
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiao-Jie Lin
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Li-Ping Wang
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yan Xi
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.,Center for Biotechnology and Interdisciplinary Studies, Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Zhi-Jun Zhang
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yong-Ting Wang
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Yuan Yang
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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9
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Demir R, Cadirci E, Akpinar E, Cayir Y, Atmaca HT, Un H, Kunak CS, Yayla M, Bayraktutan Z, Demir I. Does Bosentan Protect Diabetic Brain Alterations in Rats? The Role of Endothelin-1 in the Diabetic Brain. Basic Clin Pharmacol Toxicol 2014; 116:236-43. [DOI: 10.1111/bcpt.12318] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 08/25/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Recep Demir
- Faculty of Medicine; Department of Neurology; Ataturk University; Erzurum Turkey
| | - Elif Cadirci
- Faculty of Pharmacy; Department of Pharmacology; Ataturk University; Erzurum Turkey
| | - Erol Akpinar
- Faculty of Medicine; Department of Pharmacology; Ataturk University; Erzurum Turkey
| | - Yasemin Cayir
- Faculty of Medicine; Department of Family Medicine; Ataturk University; Erzurum Turkey
| | - Hasan Tarik Atmaca
- Faculty of Veterinary; Department of Pathology; Kırıkkale University; Kırıkkale Turkey
| | - Harun Un
- Faculty of Pharmacy; Department of Biochemistry; Agri Ibrahim Cecen University; Agri Turkey
| | - Celalettin Semih Kunak
- Faculty of Medicine; Department of Pharmacology and Toxicology; Ordu University; Ordu Turkey
| | - Muhammed Yayla
- Faculty of Medicine; Department of Pharmacology; Ataturk University; Erzurum Turkey
| | - Zafer Bayraktutan
- Department of Biochemistry; Regional Research and Education Hospital; Erzurum Turkey
| | - Ilknur Demir
- Department of Paediatry; Regional Research and Education Hospital; Erzurum Turkey
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10
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Ong PK, Meays D, Frangos JA, Carvalho LJM. A chronic scheme of cranial window preparation to study pial vascular reactivity in murine cerebral malaria. Microcirculation 2014; 20:394-404. [PMID: 23279271 DOI: 10.1111/micc.12034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 12/14/2012] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The acute implantation of a cranial window for studying cerebroarteriolar reactivity in living animals involves a highly surgically invasive craniotomy procedure at the time of experimentation, which limits its application in severely ill animals such as in the experimental murine model of cerebral malaria (ECM). To overcome this problem, a chronic window implantation scheme was designed and implemented. METHODS A partial craniotomy is first performed by creating a skull bone flap in the healthy mice, which are then left to recover for one to two weeks, followed by infection to induce ECM. Uninfected animals are utilized as control. When cranial superfusion is needed, the bone flap is retracted and window implantation completed by assembling a perfusion chamber for compound delivery to the exposed brain surface. The presurgical step is intended to minimize surgical trauma on the day of experimentation. RESULTS Chronic preparations in uninfected mice exhibited remarkably improved stability over acute ones by significantly reducing periarteriolar tissue damage and enhancing cerebroarteriolar dilator responses. The chronic scheme was successfully implemented in ECM mice, which unveiled novel preliminary insights into impaired cerebroarteriolar reactivity and eNOS dysfunction. CONCLUSION The chronic scheme presents an innovative approach for advancing our mechanistic understanding on cerebrovascular dysfunction in ECM.
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Affiliation(s)
- Peng Kai Ong
- Center for Malaria Research, La Jolla Bioengineering Institute, San Diego, CA 92121, USA.
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11
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Ergul A, Kelly-Cobbs A, Abdalla M, Fagan SC. Cerebrovascular complications of diabetes: focus on stroke. Endocr Metab Immune Disord Drug Targets 2012; 12:148-58. [PMID: 22236022 DOI: 10.2174/187153012800493477] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 09/27/2011] [Indexed: 12/18/2022]
Abstract
Cerebrovascular complications make diabetic patients 2-6 times more susceptible to a stroke event and this risk is magnified in younger individuals and in patients with hypertension and complications in other vascular beds. In addition, when patients with diabetes and hyperglycemia experience an acute ischemic stroke they are more likely to die or be severely disabled and less likely to benefit from the one FDA-approved therapy, intravenous tissue plasminogen activator. Experimental stroke models have revealed that chronic hyperglycemia leads to deficits in cerebrovascular structure and function that may explain some of the clinical observations. Increased edema, neovascularization and protease expression as well as altered vascular reactivity and tone may be involved and point to potential therapeutic targets. Further study is needed to fully understand this complex disease state and the breadth of its manifestation in the cerebrovasculature.
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Affiliation(s)
- Adviye Ergul
- Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA 30912, USA
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12
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Srivastava K, Bath PMW, Bayraktutan U. Current therapeutic strategies to mitigate the eNOS dysfunction in ischaemic stroke. Cell Mol Neurobiol 2011; 32:319-36. [PMID: 22198555 DOI: 10.1007/s10571-011-9777-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 11/29/2011] [Indexed: 12/22/2022]
Abstract
Impairment of endothelial nitric oxide synthase (eNOS) activity is implicated in the pathogenesis of endothelial dysfunction in many diseases including ischaemic stroke. The modulation of eNOS during and/or following ischaemic injury often represents a futile compensatory mechanism due to a significant decrease in nitric oxide (NO) bioavailability coupled with dramatic increases in the levels of reactive oxygen species that further neutralise NO. However, applications of a number of therapeutic agents alone or in combination have been shown to augment eNOS activity under a variety of pathological conditions by potentiating the expression and/or activity of Akt/eNOS/NO pathway components. The list of these therapeutic agents include NO donors, statins, angiotensin-converting enzyme inhibitors, calcium channel blockers, phosphodiesterase-3 inhibitors, aspirin, dipyridamole and ellagic acid. While most of these compounds exhibit anti-platelet properties and are able to up-regulate eNOS expression in endothelial cells and platelets, others suppress eNOS uncoupling and tetrahydrobiopterin (an eNOS stabiliser) oxidation. As the number of therapeutic molecules that modulate the expression and activity of eNOS increases, further detailed research is required to reveal their mode of action in preventing and/or reversing the endothelial dysfunction.
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Affiliation(s)
- Kirtiman Srivastava
- Division of Stroke, Clinical Sciences Building, Nottingham City Hospital Campus, The University of Nottingham, Nottingham, UK.
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13
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Abstract
Endothelial cells exert an enormous influence on blood vessels throughout the circulation, but their impact is particularly pronounced in the brain. New concepts have emerged recently regarding the role of this cell type and mechanisms that contribute to endothelial dysfunction and vascular disease. Activation of the renin-angiotensin system plays a prominent role in producing these abnormalities. Both oxidative stress and local inflammation are key mechanisms that underlie vascular disease of diverse etiology. Endogenous mechanisms of vascular protection are also present, including antioxidants, anti-inflammatory molecules, and peroxisome proliferator-activated receptor-γ. Despite their clear importance, studies of mechanisms that underlie cerebrovascular disease continue to lag behind studies of vascular biology in general. Identification of endogenous molecules and pathways that protect the vasculature may result in targeted approaches to prevent or slow the progression of vascular disease that causes stroke and contributes to the vascular component of dementia and Alzheimer's disease.
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Affiliation(s)
- Frank M Faraci
- Dept. of Internal Medicine, Carver College of Medicine, Univ. of Iowa, Iowa City, Iowa 52242-1081, USA.
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14
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Wajima D, Nakamura M, Horiuchi K, Miyake H, Takeshima Y, Tamura K, Motoyama Y, Konishi N, Nakase H. Enhanced cerebral ischemic lesions after two-vein occlusion in diabetic rats. Brain Res 2010; 1309:126-35. [DOI: 10.1016/j.brainres.2009.10.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Revised: 10/22/2009] [Accepted: 10/24/2009] [Indexed: 11/26/2022]
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15
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Xu HL, Vetri F, Lee HK, Ye S, Paisansathan C, Mao L, Tan F, Pelligrino DA. Estrogen replacement therapy in diabetic ovariectomized female rats potentiates postischemic leukocyte adhesion in cerebral venules via a RAGE-related process. Am J Physiol Heart Circ Physiol 2009; 297:H2059-67. [PMID: 19820198 DOI: 10.1152/ajpheart.00445.2009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In this study, we tested the hypothesis that the documented transformation of 17beta-estradiol (E2) from a counterinflammatory hormone in nondiabetic (ND) rats to a proinflammatory agent in rats with diabetes mellitus (DM) is due to an enhanced contribution from the receptor for advanced glycation end products (RAGE). Rhodamine 6G-labeled leukocytes were observed through a closed cranial window in rats. In vivo pial venular leukocyte adherence and infiltration were measured over 10 h reperfusion after transient forebrain ischemia in DM (streptozotocin) versus ND intact, ovariectomized (OVX), and E2-replaced (for 7-10 days) OVX (OVE) females. The role of RAGE was examined in two ways: 1) RAGE knockdown via topical application of RAGE antisense versus missense oligodeoxynucleotide or 2) intracerebroventricular injection of the RAGE decoy inhibitor, soluble RAGE. Among diabetic rats, the lowest levels of cortical RAGE mRNA and immunoreactivity of the RAGE ligand, AGE, were seen in OVX females, with significantly higher levels exhibited in intact and OVE females. However, results from the analysis of cortical RAGE protein only partially tracked those findings. When comparing ND to DM rats, cortical AGE immunoreactivity was significantly lower in OVE and intact females but similar in OVX rats. In DM rats, the level of postischemic leukocyte adhesion and infiltration (highest to lowest) was OVE>intact>>untreated OVX. In NDs, adhesion was highest in the untreated OVX group. Leukocyte extravasation was observed at >6 h postischemia but only in diabetic OVE and intact females and in ND OVX (untreated) rats. Pretreatment with RAGE antisense-oligodeoxynucleotide or soluble RAGE attenuated postischemic leukocyte adhesion and prevented infiltration but only in the diabetic OVE and intact groups. These results indicate that the exacerbation of postischemic leukocyte adhesion by chronic E2 replacement therapy in diabetic OVX females involves a RAGE-related mechanism. Targeting RAGE may restore the neuroprotective effect of E2 replacement therapy in diabetic females.
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Affiliation(s)
- Hao-Liang Xu
- Neuroanesthesia Research Laboratory, Department of Anesthesiology, University of Illinois at Chicago, 835 S. Wolcott Ave., Rm. E-714C, Chicago, IL 60612, USA
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Toda N, Ayajiki K, Okamura T. Cerebral Blood Flow Regulation by Nitric Oxide: Recent Advances. Pharmacol Rev 2009; 61:62-97. [DOI: 10.1124/pr.108.000547] [Citation(s) in RCA: 268] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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17
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Zhang R, Bai YG, Lin LJ, Bao JX, Zhang YY, Tang H, Cheng JH, Jia GL, Ren XL, Ma J. Blockade of AT1 receptor partially restores vasoreactivity, NOS expression, and superoxide levels in cerebral and carotid arteries of hindlimb unweighting rats. J Appl Physiol (1985) 2009; 106:251-8. [DOI: 10.1152/japplphysiol.01278.2007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies have demonstrated activation of the local renin-angiotensin system in hindlimb unweighting (HU) rat vasculature. The present study intended to identify the effects of blockade of angiotensin II (ANG II) type 1 (AT1) receptors with losartan on vascular reactivity, nitric oxide synthase (NOS) expression, and superoxide anion (O2•−) levels in 3-wk HU rat cerebral and carotid arteries. Three weeks later, vasoconstriction, vasodilatation, endothelial NOS (eNOS) and inducible NOS (iNOS) protein, as well as O2•− levels in rat cerebral and carotid arteries were examined. We found that HU enhanced maximal response to KCl/5-hydroxytryptamine ( P < 0.01) in basilar arteries and KCl/phenylephrine ( P < 0.05) in common carotid arteries from HU rats. Acetylcholine induced concentration-dependent vasodilatation in all the artery rings, but with significantly smaller amplitude in basilar ( P < 0.01) and common carotid ( P < 0.05) arteries from HU rats than those from control rats. Chronic treatment with losartan partially restored response to vasoconstrictors and acetylcholine-induced vasodilatation in basilar ( P < 0.01) and common carotid ( P < 0.05) arteries from losartan-treated HU rats. Furthermore, iNOS content in cerebral arteries and eNOS/iNOS content in carotid arteries were significantly ( P < 0.01) increased in HU rats. Meanwhile, HU increased O2•− levels in all the layers of these arteries. However, losartan restored NOS content and O2•− levels toward normal. These results suggested that the HU-induced enhancement of vasoconstriction and reduction in endothelium-dependent relaxation involved alterations in O2•− and NOS content through an ANG II/AT1 receptor signaling pathway.
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Arrick DM, Sharpe GM, Sun H, Mayhan WG. Losartan improves impaired nitric oxide synthase-dependent dilatation of cerebral arterioles in type 1 diabetic rats. Brain Res 2008; 1209:128-35. [PMID: 18400212 DOI: 10.1016/j.brainres.2008.03.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 03/11/2008] [Accepted: 03/11/2008] [Indexed: 11/16/2022]
Abstract
We examined whether activation of angiotensin-1 receptors (AT1R) could account for impaired responses of cerebral arterioles during type 1 diabetes (T1D). First, we measured responses of cerebral arterioles in nondiabetic rats to eNOS-dependent (acetylcholine and adenosine diphosphate (ADP)) and -independent (nitroglycerin) agonists before and during application of angiotensin II. Next, we examined whether losartan could improve impaired responses of cerebral arterioles during T1D. In addition, we harvested cerebral microvessels for Western blot analysis of AT1R protein and measured production of superoxide anion by brain tissue under basal conditions and in response to angiotensin II in the absence or presence of losartan. We found that angiotensin II specifically impaired eNOS-dependent reactivity of cerebral arterioles. In addition, while losartan did not alter responses in nondiabetics, losartan restored impaired eNOS-dependent vasodilatation in diabetics. Further, AT1R protein was higher in diabetics compared to nondiabetics. Finally, superoxide production was higher in brain tissue from diabetics compared to nondiabetics under basal conditions, angiotensin II increased superoxide production in nondiabetics and diabetics, and losartan decreased basal (diabetics) and angiotensin II-induced production of superoxide (nondiabetics and diabetics). We suggest that activation of AT1R during T1D plays a critical role in impaired eNOS-dependent dilatation of cerebral arterioles.
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Affiliation(s)
- Denise M Arrick
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA
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19
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Oltman CL, Kleinschmidt TL, Davidson EP, Coppey LJ, Lund DD, Yorek MA. Treatment of cardiovascular dysfunction associated with the metabolic syndrome and type 2 diabetes. Vascul Pharmacol 2008; 48:47-53. [DOI: 10.1016/j.vph.2007.11.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 10/11/2007] [Accepted: 11/14/2007] [Indexed: 11/25/2022]
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Last D, de Bazelaire C, Alsop DC, Hu K, Abduljalil AM, Cavallerano J, Marquis RP, Novak V. Global and regional effects of type 2 diabetes on brain tissue volumes and cerebral vasoreactivity. Diabetes Care 2007; 30:1193-9. [PMID: 17290035 PMCID: PMC2031924 DOI: 10.2337/dc06-2052] [Citation(s) in RCA: 179] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The aim of this study was to evaluate the regional effects of type 2 diabetes and associated conditions on cerebral tissue volumes and cerebral blood flow (CBF) regulation. RESEARCH DESIGN AND METHODS CBF was examined in 26 diabetic (aged 61.6 +/- 6.6 years) and 25 control (aged 60.4 +/- 8.6 years) subjects using continuous arterial spin labeling (CASL) imaging during baseline, hyperventilation, and CO2 rebreathing. Regional gray and white matter, cerebrospinal fluid (CSF), and white matter hyperintensity (WMH) volumes were measured on a T1-weighted inversion recovery fast-gradient echo and a fluid attenuation inversion recovery magnetic resonance imaging at 3 Tesla. RESULTS The diabetic group had smaller global white (P = 0.006) and gray (P = 0.001) matter and larger CSF (36.3%, P < 0.0001) volumes than the control group. Regional differences were observed for white matter (-13.1%, P = 0.0008) and CSF (36.3%, P < 0.0001) in the frontal region, for CSF (20.9%, P = 0.0002) in the temporal region, and for gray matter (-3.0%, P = 0.04) and CSF (17.6%, P = 0.01) in the parieto-occipital region. Baseline regional CBF (P = 0.006) and CO2 reactivity (P = 0.005) were reduced in the diabetic group. Hypoperfusion in the frontal region was associated with gray matter atrophy (P < 0.0001). Higher A1C was associated with lower CBF (P < 0.0001) and greater CSF (P = 0.002) within the temporal region. CONCLUSIONS Type 2 diabetes is associated with cortical and subcortical atrophy involving several brain regions and with diminished regional cerebral perfusion and vasoreactivity. Uncontrolled diabetes may further contribute to hypoperfusion and atrophy. Diabetic metabolic disturbance and blood flow dysregulation that affects preferentially frontal and temporal regions may have implications for cognition and balance in elderly subjects with diabetes.
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Affiliation(s)
- David Last
- Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Cedric de Bazelaire
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - David C. Alsop
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Kun Hu
- Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | | | - Jerry Cavallerano
- Beetham Eye Institute, Joslin Diabetes Center, Boston, Massachusetts
| | - Robert P. Marquis
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Vera Novak
- Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
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Toda N, Ayajiki K, Okamura T. Interaction of Endothelial Nitric Oxide and Angiotensin in the Circulation. Pharmacol Rev 2007; 59:54-87. [PMID: 17329548 DOI: 10.1124/pr.59.1.2] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Discovery of the unexpected intercellular messenger and transmitter nitric oxide (NO) was the highlight of highly competitive investigations to identify the nature of endothelium-derived relaxing factor. This labile, gaseous molecule plays obligatory roles as one of the most promising physiological regulators in cardiovascular function. Its biological effects include vasodilatation, increased regional blood perfusion, lowering of systemic blood pressure, and antithrombosis and anti-atherosclerosis effects, which counteract the vascular actions of endogenous angiotensin (ANG) II. Interactions of these vasodilator and vasoconstrictor substances in the circulation have been a topic that has drawn the special interest of both cardiovascular researchers and clinicians. Therapeutic agents that inhibit the synthesis and action of ANG II are widely accepted to be essential in treating circulatory and metabolic dysfunctions, including hypertension and diabetes mellitus, and increased availability of NO is one of the most important pharmacological mechanisms underlying their beneficial actions. ANG II provokes vascular actions through various receptor subtypes (AT1, AT2, and AT4), which are differently involved in NO synthesis and actions. ANG II and its derivatives, ANG III, ANG IV, and ANG-(1-7), alter vascular contractility with different mechanisms of action in relation to NO. This review article summarizes information concerning advances in research on interactions between NO and ANG in reference to ANG receptor subtypes, radical oxygen species, particularly superoxide anions, ANG-converting enzyme inhibitors, and ANG receptor blockers in patients with cardiovascular disease, healthy individuals, and experimental animals. Interactions of ANG and endothelium-derived relaxing factor other than NO, such as prostaglandin I2 and endothelium-derived hyperpolarizing factor, are also described.
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Affiliation(s)
- Noboru Toda
- Department of Pharmacology, Shiga University of Medical Science, Seta, Otsu, Japan.
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22
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Mayhan WG, Arrick DM, Sharpe GM, Patel KP, Sun H. Inhibition of NAD(P)H oxidase alleviates impaired NOS-dependent responses of pial arterioles in type 1 diabetes mellitus. Microcirculation 2006; 13:567-75. [PMID: 16990215 DOI: 10.1080/10739680600885194] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
OBJECTIVE The goal was to identify the role of NAD(P)H oxidase in cerebrovascular dysfunction in type 1 diabetes mellitus (T1D). METHODS In a first series of studies, rats were assigned to nondiabetic, diabetic (streptozotocin; 50 mg/kg IP), nondiabetic-apocynin (40 mg/kg/day in drinking water)-treated and diabetic-apocynin-treated groups. Two to three months later, the authors examined in vivo responses of pial arterioles to nitric oxide synthase (NOS)-dependent (acetylcholine and adenosine diphosphate (ADP)) and -independent (nitroglycerin) agonists. Next, they used Western blot analysis to examine protein levels for subunits of NAD(P)H oxidase in cerebral microvessels and parietal cortex tissue of nondiabetic and diabetic rats. Finally, they measured superoxide production by parietal cortex tissue in nondiabetic and diabetic rats. RESULTS Acetylcholine- and ADP-induced dilatation of pial arterioles was impaired in diabetic compared to nondiabetic rats. In addition, while apocynin did not alter responses in nondiabetic rats, apocynin alleviated T1D-induced impairment of NOS-dependent vasodilatation. In addition, p47phox and gp91phox proteins were elevated in cerebral microvessels and parietal cortex tissue, respectively, of diabetic compared to nondiabetic rats. Further, basal production of superoxide was increased in diabetic compared to nondiabetic rats and apocynin decreased this basal production. CONCLUSIONS The findings suggest that T1D impairs NOS-dependent reactivity of cerebral arterioles by a mechanism related to the formation of superoxide via activation of NAD(P)H oxidase.
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Affiliation(s)
- William G Mayhan
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, 68198-5850, USA.
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Novak V, Last D, Alsop DC, Abduljalil AM, Hu K, Lepicovsky L, Cavallerano J, Lipsitz LA. Cerebral blood flow velocity and periventricular white matter hyperintensities in type 2 diabetes. Diabetes Care 2006; 29:1529-34. [PMID: 16801574 PMCID: PMC1978169 DOI: 10.2337/dc06-0261] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Diabetes increases the risk for cerebromicrovascular disease, possibly through its effects on blood flow regulation. The aim of this study was to assess the effects of type 2 diabetes on blood flow velocities (BFVs) in the middle cerebral arteries and to determine the relationship between white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) and BFVs. RESEARCH DESIGN AND METHODS We measured BFVs in 28 type 2 diabetic and 22 control subjects (aged 62.3 +/- 7.2 years) using transcranial Doppler ultrasound during baseline, hyperventilation, and CO(2) rebreathing. WMHs were graded, and their volume was quantified from fluid-attenuated inversion recovery images on a 3.0 Tesla MRI. RESULTS The diabetic group demonstrated decreased mean BFVs and increased cerebrovascular resistance during baseline, hypo- and hypercapnia (P < 0.0001), and impaired CO(2) reactivity (P = 0.05). WMH volume was negatively correlated with baseline BFV (P < 0.0001). A regression model revealed that baseline BFVs were negatively associated with periventricular WMHs, HbA(1c) (A1C), and inflammatory markers and positively associated with systolic blood pressure (R(2) = 0.86, P < 0.0001). CONCLUSIONS Microvascular disease in type 2 diabetes, which manifests as white matter abnormalities on MRI, is associated with reduced cerebral BFVs, increased resistance in middle cerebral arteries, and inflammation. These findings are clinically relevant as a potential mechanism for cerebrovascular disease in elderly with type 2 diabetes.
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Affiliation(s)
- Vera Novak
- Division of Gerontology, Beth Israel Deaconess Medical Center, 110 Francis St., Boston, MA 02215, USA.
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Miyamoto A, Wada R, Inoue A, Ishiguro S, Liao JK, Nishio A. Role of angiotensin II receptor subtypes in porcine basilar artery: functional, radioligand binding, and cell culture studies. Life Sci 2006; 78:943-9. [PMID: 16223512 PMCID: PMC2641039 DOI: 10.1016/j.lfs.2005.06.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Accepted: 06/01/2005] [Indexed: 11/26/2022]
Abstract
We aimed to clarify responsiveness to angiotensin (Ang) II in the porcine basilar artery and the role of Ang II receptor subtypes by functional, radioligand binding, and cell culture studies. Ang II induced more potent contractions in the proximal part than in the distal part of isolated porcine basilar arteries. The contraction induced by Ang II was inhibited by the Ang II type 1 (AT1) receptor antagonist losartan, but the Ang II type 2 (AT2) receptor antagonist PD123319 enhanced it. After removal of the endothelium, the effect of losartan remained but the effect of PD123319 was abolished. The specific binding site of [3H]Ang II on the smooth muscle membrane was inhibited by losartan, but not by PD123319. Stimulation of angiotensin II increased nitric oxide (NO) production in cultured basilar arterial endothelial cells. This production was inhibited by PD123319 and the NO synthase inhibitor L-NG-nitroarginine. These results suggest that the contraction induced by Ang II might be mediated via the activation of AT1 receptors on the basilar arterial smooth muscle cells and be modulated via the activation of AT2 receptors on the endothelial cells, followed by NO production.
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Affiliation(s)
- Atsushi Miyamoto
- Department of Veterinary Pharmacology, Faculty of Agriculture, Kagoshima University, Kagoshima, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
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Ibrahim MA, Kanzaki T, Yamagata SI, Satoh N, Ueda S. Effect of diabetes on aortic nitric oxide synthesis in spontaneously hypertensive rats; does captopril modulate this effect? Life Sci 2005; 77:1003-14. [PMID: 15890370 DOI: 10.1016/j.lfs.2005.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2004] [Accepted: 02/03/2005] [Indexed: 11/16/2022]
Abstract
Nitric oxide (NO) is a potent regulator in the cardiovascular system; it is generated by the nitric oxide synthase (NOS) family of proteins. NO produced in endothelial cells plays a crucial role in vascular functions. The aim of this study was to clarify the effect of diabetes on aortic NO synthesis in a model of genetic hypertension and determine whether captopril modulates this effect. Diabetes was induced in ten weeks old spontaneously hypertensive rats (SHR) by streptozotocin injection. The rats were allocated into 3 groups: control group 1, non-diabetic SHR; group 2, diabetic SHR; group 3, diabetic SHR group receiving captopril at 80 mg/kg in drinking water for 4 weeks. Mean blood pressure (MBP) was measured once a week by tail-cuff method. Aortic NO metabolities (nitrite/nitrate) and endothelial NOS (NOS-3) were assayed by Griess reaction and by immunoblotting and immunohistochemistry, respectively. There was a significant decrease in nitrite/nitrate (NOx) in aortas of diabetic SHR compared with controls. The decrease of aortic NOx in diabetic SHR was accompanied by a decrease in NOS-3 expression. Captopril treatment reduced MBP without affecting either NOx level or NOS-3 expression in aortas of diabetic SHR. We conclude that STZ-induced diabetes decreased NO in aortas of SHR that may reflect endothelial cell dysfunction; captopril administration decreased MBP without affecting NO level in aortas of diabetic SHR which suggest that the blood pressure-lowering effects of captopril were independent of NO.
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Affiliation(s)
- Mohamed A Ibrahim
- Department of Drug Information and Communication, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chiba City, 260-8675, Japan
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Fujiki T, Shimokawa H, Morikawa K, Kubota H, Hatanaka M, Talukder MAH, Matoba T, Takeshita A, Sunagawa K. Endothelium-derived hydrogen peroxide accounts for the enhancing effect of an angiotensin-converting enzyme inhibitor on endothelium-derived hyperpolarizing factor-mediated responses in mice. Arterioscler Thromb Vasc Biol 2005; 25:766-71. [PMID: 15705930 DOI: 10.1161/01.atv.0000158498.19027.75] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
UNLABELLED Background- We have recently identified that endothelium-derived hydrogen peroxide (H2O2) is an endothelium-derived hyperpolarizing factor (EDHF) in animals and humans, for which endothelial nitric oxide synthase (eNOS) is an important source. Angiotensin-converting enzyme (ACE) inhibitors are known to enhance EDHF-mediated responses. In this study, we examined whether endothelium-derived H2O2 accounts for the enhancing effect of an ACE inhibitor on EDHF-mediated responses and, if so, what mechanism is involved. METHODS AND RESULTS Control and eNOS-/- mice were maintained with or without temocapril (10 mg/kg per day orally) for 4 weeks, and isometric tensions and membrane potentials of mesenteric arteries were recorded. In control mice, temocapril treatment significantly enhanced EDHF-mediated relaxations and hyperpolarizations to acetylcholine (n=8 each). Catalase, a specific scavenger of H2O2, abolished the beneficial effects of temocapril, although it did not affect endothelium-independent relaxations to sodium nitroprusside or NS1619, a direct opener of K(Ca) channels (n=6 each). Western blot analysis demonstrated that the temocapril treatment significantly upregulated the expression of eNOS. By contrast, this enhancing effect of temocapril was absent in eNOS-/- mice (n=6). CONCLUSIONS These results indicate that endothelium-derived H2O2 accounts for the enhancing effect of temocapril on EDHF-mediated responses caused in part by eNOS upregulation, further supporting our H2O2 theory.
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Affiliation(s)
- Takako Fujiki
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
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Mayhan WG, Sun H, Mayhan JF, Patel KP. Influence of exercise on dilatation of the basilar artery during diabetes mellitus. J Appl Physiol (1985) 2004; 96:1730-7. [PMID: 14729730 DOI: 10.1152/japplphysiol.01185.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Our goal was to examine whether exercise training alleviates impaired nitric oxide synthase (NOS)-dependent dilatation of the basilar artery in Type 1 diabetic rats. To test this hypothesis, we measured in vivo diameter of the basilar artery in sedentary and exercised nondiabetic and diabetic rats in response to NOS-dependent (acetylcholine) and -independent (nitroglycerin) agonists. To determine the potential role for nitric oxide in vasodilatation in sedentary and exercised nondiabetic and diabetic rats, we examined responses after NG-monomethyl-l-arginine (l-NMMA). We found that acetylcholine produced dilatation of the basilar artery that was similar in sedentary and exercised nondiabetic rats. Acetylcholine produced only minimal vasodilatation in sedentary diabetic rats. However, exercise alleviated impaired acetylcholine-induced vasodilatation in diabetic rats. Nitroglycerin produced dilatation of the basilar artery that was similar in sedentary and exercised nondiabetic and diabetic rats. l-NMMA produced similar inhibition of acetylcholine-induced dilatation of the basilar artery in sedentary and exercised nondiabetic and diabetic rats. Finally, we found that endothelial NOS (eNOS) protein in the basilar artery was higher in diabetic compared with nondiabetic rats and that exercise increased eNOS protein in the basilar artery of nondiabetic and diabetic rats. We conclude that 1) exercise can alleviate impaired NOS-dependent dilatation of the basilar artery during diabetes mellitus, 2) the synthesis and release of nitric oxide accounts for dilatation of the basilar artery to acetylcholine in sedentary and exercised nondiabetic and diabetic rats, and 3) exercise may exert its affect on cerebrovascular reactivity during diabetes by altering levels of eNOS protein in the basilar artery.
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Affiliation(s)
- William G Mayhan
- Department of Physiology and Biophysics, University of Nebraska Medical Center, 985850 Nebraska Medical Center, Omaha, Nebraska 68198-5850, USA.
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