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Feng L, Gao L. The role of neurovascular coupling dysfunction in cognitive decline of diabetes patients. Front Neurosci 2024; 18:1375908. [PMID: 38576869 PMCID: PMC10991808 DOI: 10.3389/fnins.2024.1375908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/05/2024] [Indexed: 04/06/2024] Open
Abstract
Neurovascular coupling (NVC) is an important mechanism to ensure adequate blood supply to active neurons in the brain. NVC damage can lead to chronic impairment of neuronal function. Diabetes is characterized by high blood sugar and is considered an important risk factor for cognitive impairment. In this review, we provide fMRI evidence of NVC damage in diabetic patients with cognitive decline. Combined with the exploration of the major mechanisms and signaling pathways of NVC, we discuss the effects of chronic hyperglycemia on the cellular structure of NVC signaling, including key receptors, ion channels, and intercellular connections. Studying these diabetes-related changes in cell structure will help us understand the underlying causes behind diabetes-induced NVC damage and early cognitive decline, ultimately helping to identify the most effective drug targets for treatment.
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Affiliation(s)
| | - Ling Gao
- Department of Endocrinology, Renmin Hospital of Wuhan University, Wuhan, China
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2
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Li B, Liu Y, Liu J, Sun H, Feng Y, Zhang Z, Zhang L. Cerebral multi-autoregulation model based enhanced external counterpulsation treatment planning for cerebral ischemic stroke. J Cereb Blood Flow Metab 2023; 43:1764-1778. [PMID: 37254770 PMCID: PMC10581230 DOI: 10.1177/0271678x231179542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 03/03/2023] [Accepted: 04/24/2023] [Indexed: 06/01/2023]
Abstract
Enhanced external counterpulsation (EECP) treatment for cerebral ischemic stroke patients with differing severity of stenosis, is subject to uncertainties due to the varying effects of the cerebral autoregulation mechanism on haemodynamics. The current study reports the development of a cerebral multi-autoregulation (MR) mathematical model, based on cerebral arteriole regulation of neurogenic, vascular smooth muscle reflex and shear stress mechanisms which takes into account the severity of stenosis. The model was evaluated by comparison to authentic clinical measurements of cerebral autoregulatory efficiency. Then it was applied to a 0D/3D geometric multi-scale haemodynamic model of a cerebral artery. Haemodynamic indicators were calculated under different pressurization durations of EECP to evaluate the efficacy for different stenosis lesions. Moderate stenosis of 50% to 60% produced excessive time-averaged wall shear stress in the distal area of the stenosis (>7 Pa) during prolonged pressurization and may result in damage to vascular endothelial cells. However, prolonged pressurization did not result in haemodynamic risk for severe stenosis of 70% to 80%, indicating that the duration of pressurization may be extended with increasing severity of stenosis. The current MR model accurately simulated cerebral blood flow and has relevance to the simulation of cerebral haemodynamics in a clinical setting.
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Affiliation(s)
- Bao Li
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Youjun Liu
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Jincheng Liu
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Hao Sun
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Yili Feng
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Zhe Zhang
- Department of Cardiac Surgery, Peking University Third Hospital, Beijing, China
| | - Liyuan Zhang
- Department of Biomedical Engineering, Faculty of Environment and Life, Beijing University of Technology, Beijing, China
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3
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Duarte JV, Guerra C, Moreno C, Gomes L, Castelo-Branco M. Changes in hemodynamic response function components reveal specific changes in neurovascular coupling in type 2 diabetes. Front Physiol 2023; 13:1101470. [PMID: 36703928 PMCID: PMC9872943 DOI: 10.3389/fphys.2022.1101470] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023] Open
Abstract
Type 2 Diabetes Mellitus (T2DM) is a metabolic disease that leads to multiple vascular complications with concomitant changes in human neurophysiology, which may lead to long-term cognitive impairment, and dementia. Early impairments of neurovascular coupling can be studied using event-related functional magnetic resonance imaging (fMRI) designs. Here, we aimed to characterize the changes in the hemodynamic response function (HRF) in T2DM to probe components from the initial dip to late undershoot. We investigated whether the HRF morphology is altered throughout the brain in T2DM, by extracting several parameters of the fMRI response profiles in 141 participants (64 patients with T2DM and 77 healthy controls) performing a visual motion discrimination task. Overall, the patients revealed significantly different HRFs, which extended to all brain regions, suggesting that this is a general phenomenon. The HRF in T2DM was found to be more sluggish, with a higher peak latency and lower peak amplitude, relative slope to peak, and area under the curve. It also showed a pronounced initial dip, suggesting that the initial avidity for oxygen is not compensated for, and an absent or less prominent but longer undershoot. Most HRF parameters showed a higher dispersion and variability in T2DM. In sum, we provide a definite demonstration of an impaired hemodynamic response function in the early stages of T2DM, following a previous suggestion of impaired neurovascular coupling. The quantitative demonstration of a significantly altered HRF morphology in separate response phases suggests an alteration of distinct physiological mechanisms related to neurovascular coupling, which should be considered in the future to potentially halt the deterioration of the brain function in T2DM.
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Affiliation(s)
- João Valente Duarte
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Coimbra, Portugal,Faculty of Medicine, University of Coimbra, Coimbra, Portugal,Intelligent Systems Associate Laboratory (LASI), Coimbra, Portugal
| | - Catarina Guerra
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Coimbra, Portugal
| | - Carolina Moreno
- Service of Endocrinology, Diabetes and Metabolism, Coimbra University Hospital, Coimbra, Portugal
| | - Leonor Gomes
- Service of Endocrinology, Diabetes and Metabolism, Coimbra University Hospital, Coimbra, Portugal
| | - Miguel Castelo-Branco
- Coimbra Institute for Biomedical Imaging and Translational Research (CIBIT), Institute for Nuclear Sciences Applied to Health (ICNAS), University of Coimbra, Coimbra, Portugal,Faculty of Medicine, University of Coimbra, Coimbra, Portugal,Intelligent Systems Associate Laboratory (LASI), Coimbra, Portugal,*Correspondence: Miguel Castelo-Branco,
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Gonçalves JS, Seiça RM, Laranjinha J, Lourenço CF. Impairment of neurovascular coupling in the hippocampus due to decreased nitric oxide bioavailability supports early cognitive dysfunction in type 2 diabetic rats. Free Radic Biol Med 2022; 193:669-675. [PMID: 36372286 DOI: 10.1016/j.freeradbiomed.2022.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/01/2022] [Accepted: 11/07/2022] [Indexed: 11/13/2022]
Abstract
Numerous epidemiological and preclinical studies have established a strong correlation between type 2 diabetes (T2DM) and cognitive impairment and T2DM is now established as an undisputable risk factor in different forms of dementia. However, the mechanisms underlying cognitive impairment in T2DM are still not fully understood. The temporal and spatial coupling between neuronal activity and cerebral blood flow (CBF) - neurovascular coupling (NVC) - is essential for normal brain function. Neuronal-derived nitric oxide (⦁NO) produced through the nNOS-NMDAr pathway, is recognized as a key messenger in NVC, especially in the hippocampus. Of note, impaired hippocampal perfusion in T2DM patients has been closely linked to learning and memory dysfunction. In this study, we aimed to investigate the functionality of NVC, in terms of neuronal-•NO signaling and spatial memory performance, in young Goto-Kakizaki (GK) rats, a non-obese model of T2DM. For that, we performed direct and simultaneous measurements of •NO concentration dynamics and microvascular CBF changes in the hippocampus upon glutamatergic activation. We found that limited •NO bioavailability, connected to shorter and faster •NO transients in response to glutamatergic neuronal activation, is associated with decreased hemodynamic responses and a decline in spatial memory performance. This evidence supports a close mechanistic association between neuronal-triggered •NO concentration dynamics in the hippocampus, local microvascular responses, and cognitive performance in young diabetic animals, establishing the functionality of NVC as a critical early factor to consider in the cascade of events leading to cognitive decline in T2DM. These results suggest that strategies capable to overcome the limited •NO bioavailability in early stages of T2DM and maintaining a functional NVC pathway may configure pertinent therapeutic approaches to mitigate the risk for cognitive impairment in T2DM.
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Affiliation(s)
- João S Gonçalves
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Raquel M Seiça
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.
| | - Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.
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Varga BT, Gáspár A, Ernyey AJ, Hutka B, Tajti BT, Zádori ZS, Gyertyán I. Introduction of a pharmacological neurovascular uncoupling model in rats based on results of mice. Physiol Int 2022. [PMID: 36057105 DOI: 10.1556/2060.2022.00226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/02/2022] [Accepted: 05/19/2022] [Indexed: 02/18/2024]
Abstract
Our aim was to establish a pharmacologically induced neurovascular uncoupling (NVU) method in rats as a model of human cognitive decline. Pharmacologically induced NVU with subsequent neurological and cognitive defects was described in mice, but not in rats so far. We used 32 male Hannover Wistar rats. NVU was induced by intraperitoneal administration of a pharmacological "cocktail" consisting of N-(methylsulfonyl)-2-(2-propynyloxy)-benzenehexanamide (MSPPOH, a specific inhibitor of epoxyeicosatrienoic acid-producing epoxidases, 5 mg kg-1), L-NG-nitroarginine methyl ester (L-NAME, a nitric oxide synthase inhibitor, 10 mg kg-1) and indomethacin (a nonselective inhibitor of cyclooxygenases, 1 mg kg-1) and injected twice daily for 8 consecutive days. Cognitive performance was tested in the Morris water-maze and fear-conditioning assays. We also monitored blood pressure. In a terminal operation a laser Doppler probe was used to detect changes in blood-flow (CBF) in the barrel cortex while the contralateral whisker pad was stimulated. Brain and small intestine tissue samples were collected post mortem and examined for prostaglandin E2 (PGE2) level. Animals treated with the "cocktail" showed no impairment in their performance in any of the cognitive tasks. They had higher blood pressure and showed cca. 50% decrease in CBF. Intestinal bleeding and ulcers were found in some animals with significantly decreased levels of PGE2 in the brain and small intestine. Although we could evoke NVU by the applied mixture of pharmacons, it also induced adverse side effects such as hypertension and intestinal malformations while the treatment did not cause cognitive impairment. Thus, further refinements are still required for the development of an applicable model.
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Affiliation(s)
- Bence Tamás Varga
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Attila Gáspár
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Aliz Judit Ernyey
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Barbara Hutka
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Brigitta Tekla Tajti
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Zoltán Sándor Zádori
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - István Gyertyán
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
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Impact of diabetes and ischemic stroke on the cerebrovasculature: A female perspective. Neurobiol Dis 2022; 167:105667. [PMID: 35227927 PMCID: PMC9615543 DOI: 10.1016/j.nbd.2022.105667] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/25/2022] [Accepted: 02/17/2022] [Indexed: 01/16/2023] Open
Abstract
There is a very complex interaction between the brain and the cerebral vasculature to meet the metabolic demands of the brain for proper function. Preservation of vascular networks and cerebrovascular function ultimately plays a key role in this intricate communication within the brain in health and disease. Experimental evidence showed that diabetes not only affects the architecture of cerebral blood arteries causing adverse remodeling, pathological neovascularization, and vasoregression, but also alters cerebrovascular function resulting in compromised myogenic reactivity and endothelial dysfunction. Coupled with the disruption of blood brain barrier (BBB) integrity, changes in blood flow and microbleeds into the brain can rapidly occur. When an ischemic insult is superimposed on this pathology, not only is the neurovascular injury greater, but repair mechanisms fail, resulting in greater physical and cognitive deficits. While clinically it is known that women suffer disproportionately from diabetes as well as ischemic stroke and post-stroke cognitive impairment, the cerebrovascular architecture, patho/physiology, as well as cerebrovascular contributions to stroke recovery in female and diabetic animal models are inadequately studied and highlighted in this review.
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7
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Wolf V, Abdul Y, Ergul A. Novel Targets and Interventions for Cognitive Complications of Diabetes. Front Physiol 2022; 12:815758. [PMID: 35058808 PMCID: PMC8764363 DOI: 10.3389/fphys.2021.815758] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/08/2021] [Indexed: 01/16/2023] Open
Abstract
Diabetes and cognitive dysfunction, ranging from mild cognitive impairment to dementia, often coexist in individuals over 65 years of age. Vascular contributions to cognitive impairment/dementia (VCID) are the second leading cause of dementias under the umbrella of Alzheimer's disease and related dementias (ADRD). Over half of dementia patients have VCID either as a single pathology or a mixed dementia with AD. While the prevalence of type 2 diabetes in individuals with dementia can be as high as 39% and diabetes increases the risk of cerebrovascular disease and stroke, VCID remains to be one of the less understood and less studied complications of diabetes. We have identified cerebrovascular dysfunction and compromised endothelial integrity leading to decreased cerebral blood flow and iron deposition into the brain, respectively, as targets for intervention for the prevention of VCID in diabetes. This review will focus on targeted therapies that improve endothelial function or remove iron without systemic effects, such as agents delivered intranasally, that may result in actionable and disease-modifying novel treatments in the high-risk diabetic population.
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Affiliation(s)
- Victoria Wolf
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Yasir Abdul
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States,*Correspondence: Yasir Abdul,
| | - Adviye Ergul
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States,Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
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Huber G, Ogrodnik M, Wenzel J, Stölting I, Huber L, Will O, Peschke E, Matschl U, Hövener JB, Schwaninger M, Jurk D, Raasch W. Telmisartan prevents high-fat diet-induced neurovascular impairments and reduces anxiety-like behavior. J Cereb Blood Flow Metab 2021; 41:2356-2369. [PMID: 33730932 PMCID: PMC8393307 DOI: 10.1177/0271678x211003497] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Angiotensin II receptor blockers (telmisartan) prevent rodents from diet-induced obesity and improve their metabolic status. Hyperglycemia and obesity are associated with reduced cerebral blood flow and neurovascular uncoupling which may lead to behavioral deficits. We wanted to know whether a treatment with telmisartan prevents these changes in obesity.We put young mice on high-fat diet and simultaneously treated them with telmisartan. At the end of treatment, we performed laser speckle imaging and magnetic resonance imaging to assess the effect on neurovascular coupling and cerebral blood flow. Different behavioral tests were used to investigate cognitive function.Mice developed diet-induced obesity and after 16, not 8 weeks of high-fat diet, however, the response to whisker pad stimulation was about 30% lower in obese compared to lean mice. Simultaneous telmisartan treatment increased the response again by 10% compared to obese mice. Moreover, telmisartan treatment normalized high-fat diet-induced reduction of cerebral blood flow and prevented a diet-induced anxiety-like behavior. In addition to that, telmisartan affects cellular senescence and string vessel formation in obesity.We conclude, that telmisartan protects against neurovascular unit impairments in a diet-induced obesity setting and may play a role in preventing obesity related cognitive deficits in Alzheimer's disease.
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Affiliation(s)
- Gianna Huber
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany.,CBBM (Centre for Brain, Behavior and Metabolism), University of Lübeck, Lübeck, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
| | - Mikolaj Ogrodnik
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester MN, USA.,Ludwig Boltzmann Research Group Senescence and Healing of Wounds at LBI Trauma, Vienna, Austria
| | - Jan Wenzel
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany.,CBBM (Centre for Brain, Behavior and Metabolism), University of Lübeck, Lübeck, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
| | - Ines Stölting
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany.,CBBM (Centre for Brain, Behavior and Metabolism), University of Lübeck, Lübeck, Germany
| | - Lukas Huber
- Section Biomedical Imaging, MOIN CC, Department of Radiology and Neuroradiology, UKSH, Kiel University, Kiel, Germany
| | - Olga Will
- Section Biomedical Imaging, MOIN CC, Department of Radiology and Neuroradiology, UKSH, Kiel University, Kiel, Germany
| | - Eva Peschke
- Section Biomedical Imaging, MOIN CC, Department of Radiology and Neuroradiology, UKSH, Kiel University, Kiel, Germany
| | - Urte Matschl
- Department Virus Immunology, Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Jan-Bernd Hövener
- Section Biomedical Imaging, MOIN CC, Department of Radiology and Neuroradiology, UKSH, Kiel University, Kiel, Germany
| | - Markus Schwaninger
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany.,CBBM (Centre for Brain, Behavior and Metabolism), University of Lübeck, Lübeck, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
| | - Diana Jurk
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester MN, USA
| | - Walter Raasch
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany.,CBBM (Centre for Brain, Behavior and Metabolism), University of Lübeck, Lübeck, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
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Guo Z, Jia J, Tu Y, Jin C, Guo C, Song F, Wu X, Bao H, Fan W. Altered Jagged1-Notch1 Signaling in Enhanced Dysfunctional Neovascularization and Delayed Angiogenesis After Ischemic Stroke in HFD/STZ Induced Type 2 Diabetes Rats. Front Physiol 2021; 12:687947. [PMID: 34305641 PMCID: PMC8297620 DOI: 10.3389/fphys.2021.687947] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/14/2021] [Indexed: 11/17/2022] Open
Abstract
Diabetes exacerbates brain damage in cerebral ischemic stroke. Our previous study has demonstrated that after cerebral ischemia, type 2 diabetes rats displayed worse neurological outcomes, larger cerebral infarction and severer blood-brain barrier disruption. However, our knowledge of the mechanisms of how diabetes impacts the cerebrovascular repair process is limited. This study was aimed to characterize structural alterations and potential mechanisms in brain microvessels before and after ischemic stroke in type 2 diabetic rats treated with high-fat diet and streptozotocin (HFD/STZ). Furtherly, we tested our hypothesis that dysregulated intercellular Jagged1-Notch1 signaling was involved in the dysfunctional cerebral neovascularization both before and after ischemic stroke in HFD/STZ rats. In our study, we found increased yet dysfunctional neovascularization with activated Jagged1-Notch1 signaling in the cerebrovasculature before cerebral ischemia in HFD/STZ rats compared with non-diabetic rats. Furthermore, we observed delayed angiogenesis as well as suppressed Jagged1-Notch1 signaling after ischemic stroke. Our results elucidate the potential mechanisms underlying diabetes-related cerebral microvasculature dysfunction after ischemic stroke.
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Affiliation(s)
- Zhihui Guo
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Jia Jia
- Department of Neurology, Shanghai Xuhui District Central Hospital, Shanghai, China
| | - Yanling Tu
- Department of Neurology, Zhongshan Hospital, Xiamen University, Xiamen, China
| | - Chang Jin
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Cen Guo
- Department of Neurology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Feifei Song
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Xuqing Wu
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Haifeng Bao
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Wei Fan
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
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Shao JW, Wang JD, He Q, Yang Y, Zou YY, Su W, Xiang ST, Li JB, Fang J. Three-dimensional-arterial spin labeling perfusion correlation with diabetes-associated cognitive dysfunction and vascular endothelial growth factor in type 2 diabetes mellitus rat. World J Diabetes 2021; 12:499-513. [PMID: 33889293 PMCID: PMC8040076 DOI: 10.4239/wjd.v12.i4.499] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 01/12/2021] [Accepted: 03/08/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Type 2 diabetes mellitus (T2DM) has been strongly associated with an increased risk of developing cognitive dysfunction and dementia. The mechanisms of diabetes-associated cognitive dysfunction (DACD) have not been fully elucidated to date. Some studies proved lower cerebral blood flow (CBF) in the hippocampus was associated with poor executive function and memory in T2DM. Increasing evidence showed that diabetes leads to abnormal vascular endothelial growth factor (VEGF) expression and CBF changes in humans and animal models. In this study, we hypothesized that DACD was correlated with CBF alteration as measured by three-dimensional (3D) arterial spin labeling (3D-ASL) and VEGF expression in the hippocampus.
AIM To assess the correlation between CBF (measured by 3D-ASL and VEGF expression) and DACD in a rat model of T2DM.
METHODS Forty Sprague-Dawley male rats were divided into control and T2DM groups. The T2DM group was established by feeding rats a high-fat diet and glucose to induce impaired glucose tolerance and then injecting them with streptozotocin to induce T2DM. Cognitive function was assessed using the Morris water maze experiment. The CBF changes were measured by 3D-ASL magnetic resonance imaging. VEGF expression was determined using immunofluorescence.
RESULTS The escape latency time significantly reduced 15 wk after streptozotocin injection in the T2DM group. The total distance traveled was longer in the T2DM group; also, the platform was crossed fewer times. The percentage of distance in the target zone significantly decreased. CBF decreased in the bilateral hippocampus in the T2DM group. No difference was found between the right CBF value and the left CBF value in the T2DM group. The VEGF expression level in the hippocampus was lower in the T2DM group and correlated with the CBF value. The escape latency negatively correlated with the CBF value. The number of rats crossing the platform positively correlated with the CBF value.
CONCLUSION Low CBF in the hippocampus and decreased VEGF expression might be crucial in DACD. CBF measured by 3D-ASL might serve as a noninvasive imaging biomarker for cognitive impairment associated with T2DM.
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Affiliation(s)
- Ju-Wei Shao
- Department of Radiology, The Second People’s Hospital of Yunnan Province, The Affiliated Hospital of Yunnan University, Kunming 650021, Yunnan Province, China
- College of Public Health, Kunming Medical University, Kunming 650500, Yunnan Province, China
| | - Jin-De Wang
- College of Clinical Medicine, Kunming Medical University, Kunming 650500, Yunnan Province, China
| | - Qian He
- Department of Radiology, The Second People’s Hospital of Yunnan Province, The Affiliated Hospital of Yunnan University, Kunming 650021, Yunnan Province, China
| | - Ying Yang
- Department of Endocrinology and Metabolism, The Second People’s Hospital of Yunnan Province, The Affiliated Hospital of Yunnan University, Kunming 650021, Yunnan Province, China
| | - Ying-Ying Zou
- Department of Pathology and Pathophysiology, Kunming Medical University, Kunming 650021, Yunnan Province, China
| | - Wei Su
- Department of Radiology, The Second People’s Hospital of Yunnan Province, The Affiliated Hospital of Yunnan University, Kunming 650021, Yunnan Province, China
| | - Shu-Tian Xiang
- Department of Radiology, The Second People’s Hospital of Yunnan Province, The Affiliated Hospital of Yunnan University, Kunming 650021, Yunnan Province, China
| | - Jian-Bo Li
- Department of Radiology, The Second People’s Hospital of Yunnan Province, The Affiliated Hospital of Yunnan University, Kunming 650021, Yunnan Province, China
| | - Jing Fang
- Institute for Health Sciences, Kunming Medical University, Kunming 650500, Yunnan Province, China
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11
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Chandran R, Li W, Ahmed HA, Dong G, Ward RA, He L, Doueiry C, Ergul A. Diabetic rats are more susceptible to cognitive decline in a model of microemboli-mediated vascular contributions to cognitive impairment and dementia. Brain Res 2020; 1749:147132. [PMID: 33002484 DOI: 10.1016/j.brainres.2020.147132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/26/2020] [Accepted: 09/15/2020] [Indexed: 12/17/2022]
Abstract
Vascular disease plays an important role in all kinds of cognitive impairment and dementia. Diabetes increases the risk of vascular disease and dementia. However, it is not clear how existing vascular disease in the brain accelerates the development of small vessel disease and promotes cognitive dysfunction in diabetes. We used microemboli (ME) injection model in the current study to test the hypothesis that cerebrovascular dysfunction in diabetes facilitates entrapment of ME leading to inflammation and cognitive decline. We investigated cognitive function, axonal/white matter (WM) changes, neurovascular coupling, and microglial activation in control and diabetic male and female Wistar rats subjected to sham or low/high dose ME injection. Diabetic male animals had cognitive deficits, WM demyelination and greater microglial activation than the control animals even at baseline. Functional hyperemia gradually declined in diabetic male animals after ME injection. Both low and high ME injection worsened WM damage and increased microglial activation in diabetic male and female animals. Low ME did not cause cognitive decline in controls, while promoting learning/memory deficits in diabetic female rats and no further decline in diabetic male animals. High ME led to cognitive decline in control male rats and exacerbated the deficits in diabetic cohort. These results suggest that the existing cerebrovascular dysfunction in diabetes may facilitate ME-mediated demyelination leading to cognitive decline. It is important to integrate comorbidities/sex as a biological variable into experimental models for the development of preventive or therapeutic targets.
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Affiliation(s)
- Raghavendar Chandran
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Weiguo Li
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States.
| | - Heba A Ahmed
- Department of Anatomy and Neurobiology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - Guangkuo Dong
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA, United States
| | - Rebecca A Ward
- Department of Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Lianying He
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Caren Doueiry
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States
| | - Adviye Ergul
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, United States
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12
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Dysfunction of the neurovascular unit in diabetes-related neurodegeneration. Biomed Pharmacother 2020; 131:110656. [PMID: 32841897 DOI: 10.1016/j.biopha.2020.110656] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 12/13/2022] Open
Abstract
In current aging societies, diabetes mellitus and neurodegenerative diseases represented by Alzheimer's disease are highly prevalent among adults, especially the elderly all over the world. It is worth noting that a substantial body of evidence suggests diabetes contributes to accelerated neurodegenerative processes and the decline of cognition. Over the last few years, some studies have indicated neurovascular uncoupling and disrupted functional connectivity in the early stages of many neurodegenerative diseases, and the concept of the neurovascular unit (NVU) has been highlighted to understand the initiation and progression of neurodegenerative diseases recently. Considering that some components of the NVU are also demonstrated to have abnormal morphology and function under the condition of diabetes, we propose the hypothesis that diabetes may promote the onset and development of neurodegenerative diseases by impairing the integrity of the NVU, named Diabetes-NVU-Neurodegeneration Hypothesis. The existing body of literature supporting the hypothesis and elucidating the underlying mechanisms will be summarized in this review.
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13
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Wang S, Lv W, Zhang H, Liu Y, Li L, Jefferson JR, Guo Y, Li M, Gao W, Fang X, Paul IA, Rajkowska G, Shaffery JP, Mosley TH, Hu X, Liu R, Wang Y, Yu H, Roman RJ, Fan F. Aging exacerbates impairments of cerebral blood flow autoregulation and cognition in diabetic rats. GeroScience 2020; 42:1387-1410. [PMID: 32696219 DOI: 10.1007/s11357-020-00233-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/08/2020] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus (DM) is a leading risk factor for aging-related dementia; however, the underlying mechanisms are not well understood. The present study, utilizing a non-obese T2DN diabetic model, demonstrates that the myogenic response of the middle cerebral artery (MCA) and parenchymal arteriole (PA) and autoregulation of cerebral blood flow (CBF) in the surface and deep cortex were impaired at both young and old ages. The impaired CBF autoregulation was more severe in old than young DM rats, and in the deep than the surface cortex. The myogenic tone of the MCA was enhanced at perfusion pressure in the range of 40-100 mmHg in young DM rats but was reduced at 140-180 mmHg in old DM rats. No change of the myogenic tone of the PA was observed in young DM rats, whereas it was significantly reduced at 30-60 mmHg in old DM rats. Old DM rats had enhanced blood-brain barrier (BBB) leakage and neurodegeneration, reduced vascular density, tight junction, and pericyte coverage on cerebral capillaries in the CA3 region in the hippocampus. Additionally, DM rats displayed impaired functional hyperemia and spatial learning and short- and long-term memory at both young and old ages. Old DM rats had impaired non-spatial short-term memory. These results revealed that impaired CBF autoregulation and enhanced BBB leakage plays an essential role in the pathogenesis of age- and diabetes-related dementia. These findings will lay the foundations for the discovery of anti-diabetic therapies targeting restoring CBF autoregulation to prevent the onset and progression of dementia in elderly DM.
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Affiliation(s)
- Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Wenshan Lv
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.,Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Longyang Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Joshua R Jefferson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Ya Guo
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Man Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Wenjun Gao
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Ian A Paul
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Grazyna Rajkowska
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - James P Shaffery
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Thomas H Mosley
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, 39216, USA.,Department of Medicine (Geriatrics), University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Xinlin Hu
- Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Ruen Liu
- Department of Neurosurgery, Peking University People's Hospital, Beijing, 100044, China
| | - Yangang Wang
- Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
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14
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Abstract
Blood flow in the retina increases in response to light-evoked neuronal activity, ensuring that retinal neurons receive an adequate supply of oxygen and nutrients as metabolic demands vary. This response, termed "functional hyperemia," is disrupted in diabetic retinopathy. The reduction in functional hyperemia may result in retinal hypoxia and contribute to the development of retinopathy. This review will discuss the neurovascular coupling signaling mechanisms that generate the functional hyperemia response in the retina, the changes to neurovascular coupling that occur in diabetic retinopathy, possible treatments for restoring functional hyperemia and retinal oxygen levels, and changes to functional hyperemia that occur in the diabetic brain.
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15
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Abstract
PURPOSE To review the recent developments on the effect of chronic high mean arterial blood pressure (MAP) on cerebral blood flow (CBF) autoregulation and supporting the notion that CBF autoregulation impairment has connection with chronic cerebral diseases. Method: A narrative review of all the relevant papers known to the authors was conducted. Results: Our understanding of the connection between cerebral perfusion impairment and chronic high MAP and cerebral disease is rapidly evolving, from cerebral perfusion impairment being the result of cerebral diseases to being the cause of cerebral diseases. We now better understand the intertwined impact of hypertension and Alzheimer's disease (AD) on cerebrovascular sensory elements and recognize cerebrovascular elements that are more vulnerable to these diseases. Conclusion: We conclude with the suggestion that the sensory elements pathology plays important roles in intertwined mechanisms of chronic high MAP and AD that impact cerebral perfusion.
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Affiliation(s)
- Noushin Yazdani
- College of Public Health, University of South Florida , Tampa, FL, USA
| | - Mark S Kindy
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida , Tampa, FL, USA.,Biomedical Research, James A. Haley VA Medical Center , Tampa, FL, USA
| | - Saeid Taheri
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida , Tampa, FL, USA.,Byrd Neuroscience Institute, University of South Florida , Tampa, FL, USA
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16
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Jackson L, Li W, Abdul Y, Dong G, Baban B, Ergul A. Diabetic Stroke Promotes a Sexually Dimorphic Expansion of T Cells. Neuromolecular Med 2019; 21:445-453. [PMID: 31197651 PMCID: PMC6884673 DOI: 10.1007/s12017-019-08554-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/04/2019] [Indexed: 12/31/2022]
Abstract
We recently reported that diabetes negates the cerebrovascular protection typically seen in adult female rats resulting in cognitive impairment, which is worsened by increased parenchymal bleeding and edema after ischemic stroke. Although women experience more severe diabetes and suffer from a higher rate of diabetic complications, including stroke and cognitive impairment, underlying mechanisms contributing to sex differences are limited. Emerging evidence suggests interleukin (IL)-17 contributes to cerebrovascular pathologies: (1) high salt diet-mediated expansion of IL-17-producing T cells (Th17) in the gut microbiome promotes cerebrovascular dysfunction and cognitive impairment in male mice, (2) increased IL-17-producing γδTCR cells exacerbates stroke injury in male mice, and (3) IL-17 promotes rupture of cerebral aneurysms in female mice. Based on these premises, we investigated the potential involvement of IL-17-producing inflammatory cells in cerebrovascular dysfunction and post-stroke vascular injury in diabetes by measuring intestinal, circulating, or cerebral T cell profiles as well as in plasma IL-17 in both sexes. Cell suspensions prepared from naive or stroked (3 days after stroke) diabetic and control rats were analyzed by flow cytometry, and IL-17 levels were measured in plasma using ELISA. Diabetes deferentially promoted the expansion of cerebral Th17 cells in females. In response to stroke, diabetes had a sexually dimorphic effect on the expansion of numerous T cell profiles. These results suggest that a better understanding of the role of IL-17-producing cells in diabetes may identify potential avenues in which the molecular mechanisms contributing to these sex differences can be further elucidated.
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Affiliation(s)
- Ladonya Jackson
- Program in Clinical and Experimental Therapeutics, University of Georgia, Augusta, GA, USA
| | - Weiguo Li
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Ave. MSC 908, Charleston, SC, 29425, USA
- Ralph Johnson Veterans Affairs Medical Center, Charleston, SC, USA
| | - Yasir Abdul
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Ave. MSC 908, Charleston, SC, 29425, USA
- Ralph Johnson Veterans Affairs Medical Center, Charleston, SC, USA
| | - Guangkuo Dong
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Babak Baban
- Department of Oral Biology, Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Adviye Ergul
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Ave. MSC 908, Charleston, SC, 29425, USA.
- Ralph Johnson Veterans Affairs Medical Center, Charleston, SC, USA.
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17
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Zhang P, Ma L, Yang Z, Li H, Gao Z. Study on the detoxification mechanisms to 5,10,15,20-tetrakis (4-sulfonatophenyl) porphyrinato iron(III) chloride (FeTPPS), an efficient pro-oxidant of heme water-soluble analogue. J Inorg Biochem 2018; 189:40-52. [DOI: 10.1016/j.jinorgbio.2018.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 08/19/2018] [Accepted: 08/30/2018] [Indexed: 11/30/2022]
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18
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Li W, Abdul Y, Ward R, Ergul A. Endothelin and diabetic complications: a brain-centric view. Physiol Res 2018; 67:S83-S94. [PMID: 29947530 DOI: 10.33549/physiolres.933833] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The global epidemic of diabetes is of significant concern. Diabetes associated vascular disease signifies the principal cause of morbidity and mortality in diabetic patients. It is also the most rapidly increasing risk factor for cognitive impairment, a silent disease that causes loss of creativity, productivity, and quality of life. Small vessel disease in the cerebral vasculature plays a major role in the pathogenesis of cognitive impairment in diabetes. Endothelin system, including endothelin-1 (ET-1) and the receptors (ET(A) and ET(B)), is a likely candidate that may be involved in many aspects of the diabetes cerebrovascular disease. In this review, we took a brain-centric approach and discussed the role of the ET system in cerebrovascular and cognitive dysfunction in diabetes.
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Affiliation(s)
- W Li
- Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia, USA, Department of Physiology, Augusta University, Augusta, Georgia, USA.
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19
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Li W, Valenzuela JP, Ward R, Abdelbary M, Dong G, Fagan SC, Ergul A. Post-stroke neovascularization and functional outcomes differ in diabetes depending on severity of injury and sex: Potential link to hemorrhagic transformation. Exp Neurol 2018; 311:106-114. [PMID: 30243988 DOI: 10.1016/j.expneurol.2018.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 09/05/2018] [Accepted: 09/18/2018] [Indexed: 01/04/2023]
Abstract
Diabetes is associated with increased risk and worsened outcome of stroke. Previous studies showed that male diabetic animals had greater hemorrhagic transformation (HT), profound loss of cerebral vasculature, and poor behavioral outcomes after ischemic stroke induced by suture or embolic middle cerebral artery occlusion (MCAO). Females are protected from stroke until reaching the menopause age, but young females with diabetes have a higher risk of stroke and women account for the majority of stroke mortality. The current study postulated that diabetes is associated with greater vascular injury and exacerbated sensorimotor and cognitive outcome after stroke even in young female animals. Male and female control and diabetic animals were subjected to transient MCAO and followed for 3 or 14 days to assess the neurovascular injury and repair. The vascularization indices after stroke were lower in male diabetic animals with 90-min but not 60-min ischemia/reperfusion injury, while there was no change in female groups. Cognitive deficits were exacerbated in both male and female groups regardless of the injury period, while the sensorimotor dysfunction was worsened in male diabetic animals with longer ischemia time. These results suggest that diabetes negates the protection afforded by sex in young female animals, and post-stroke vascularization pattern is influenced by the degree of injury and correlates with functional outcome in both sexes. Vasculoprotection after acute ischemic stroke may provide a novel therapeutic strategy in diabetes.
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Affiliation(s)
- Weiguo Li
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States; Charlie Norwood VA Medical Center, Augusta, GA, United States.
| | - John Paul Valenzuela
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Rebecca Ward
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States; Department of Neuroscience & Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Mahmoud Abdelbary
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Guangkuo Dong
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Susan C Fagan
- Charlie Norwood VA Medical Center, Augusta, GA, United States; Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, United States
| | - Adviye Ergul
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, United States; Charlie Norwood VA Medical Center, Augusta, GA, United States
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20
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Coucha M, Abdelsaid M, Ward R, Abdul Y, Ergul A. Impact of Metabolic Diseases on Cerebral Circulation: Structural and Functional Consequences. Compr Physiol 2018; 8:773-799. [PMID: 29687902 DOI: 10.1002/cphy.c170019] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Metabolic diseases including obesity, insulin resistance, and diabetes have profound effects on cerebral circulation. These diseases not only affect the architecture of cerebral blood arteries causing adverse remodeling, pathological neovascularization, and vasoregression but also alter the physiology of blood vessels resulting in compromised myogenic reactivity, neurovascular uncoupling, and endothelial dysfunction. Coupled with the disruption of blood brain barrier (BBB) integrity, changes in blood flow and microbleeds into the brain rapidly occur. This overview is organized into sections describing cerebrovascular architecture, physiology, and BBB in these diseases. In each section, we review these properties starting with larger arteries moving into smaller vessels. Where information is available, we review in the order of obesity, insulin resistance, and diabetes. We also tried to include information on biological variables such as the sex of the animal models noted since most of the information summarized was obtained using male animals. © 2018 American Physiological Society. Compr Physiol 8:773-799, 2018.
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Affiliation(s)
- Maha Coucha
- South University, School of Pharmacy, Savannah, Georgia, USA
| | | | - Rebecca Ward
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Yasir Abdul
- Charlie Norwood VA Medical Center, Augusta, Georgia, USA.,Department of Physiology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Adviye Ergul
- Charlie Norwood VA Medical Center, Augusta, Georgia, USA.,Department of Physiology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
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21
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Thompson JA, Larion S, Mintz JD, Belin de Chantemèle EJ, Fulton DJ, Stepp DW. Genetic Deletion of NADPH Oxidase 1 Rescues Microvascular Function in Mice With Metabolic Disease. Circ Res 2017; 121:502-511. [PMID: 28684629 DOI: 10.1161/circresaha.116.309965] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 06/19/2017] [Accepted: 07/05/2017] [Indexed: 01/04/2023]
Abstract
RATIONALE Early vascular changes in metabolic disease that precipitate the development of cardiovascular complications are largely driven by reactive oxygen species accumulation, yet the extent to which excess reactive oxygen species derive from specific NADPH oxidase isoforms remains ill defined. OBJECTIVE Identify the role of Nox1 in the development of microvascular dysfunction in metabolic disease. METHODS AND RESULTS Four genotypes were generated by breeding Nox1 knockout mice with db/db mice: lean (HdbWnox1), lean Nox1 knockout (HdbKnox1), obese (KdbWnox1), and obese KK (KdbKnox1). The degree of adiposity, insulin resistance, and dyslipidemia in KW mice was not influenced by Nox1 deletion as determined by nuclear magnetic resonance spectroscopy, glucose tolerance tests, and plasma analyses. Endothelium-dependent responses to acetylcholine in pressurized mesenteric arteries were reduced in KW versus HW (P<0.01), whereas deletion of Nox1 in KW mice normalized dilation. Vasodilator responses after inhibition of NO synthase blunted acetylcholine responses in KK and lean controls, but had no impact in KW, attributing recovered dilatory capacity in KK to normalization of NO. Acetylcholine responses were improved (P<0.05) with Tempol, and histochemistry revealed oxidative stress in KW animals, whereas Tempol had no impact and reactive oxygen species staining was negligible in KK. Blunted dilatory responses to an NO donor and loss of myogenic tone in KW animals were also rescued with Nox1 deletion. CONCLUSIONS Nox1 deletion reduces oxidant load and restores microvascular health in db/db mice without influencing the degree of metabolic dysfunction. Therefore, targeted Nox1 inhibition may be effective in the prevention of vascular complications.
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Affiliation(s)
- Jennifer A Thompson
- From the Vascular Biology Center (J.A.T., S.L., J.D.M., E.J.B.d.C., D.J.F., D.W.S.), Department of Physiology (D.W.S), Department of Pharmacology (D.J.F.), and Department of Medicine (S.L., E.J.B.d.C.), Augusta University, GA
| | - Sebastian Larion
- From the Vascular Biology Center (J.A.T., S.L., J.D.M., E.J.B.d.C., D.J.F., D.W.S.), Department of Physiology (D.W.S), Department of Pharmacology (D.J.F.), and Department of Medicine (S.L., E.J.B.d.C.), Augusta University, GA
| | - James D Mintz
- From the Vascular Biology Center (J.A.T., S.L., J.D.M., E.J.B.d.C., D.J.F., D.W.S.), Department of Physiology (D.W.S), Department of Pharmacology (D.J.F.), and Department of Medicine (S.L., E.J.B.d.C.), Augusta University, GA
| | - Eric J Belin de Chantemèle
- From the Vascular Biology Center (J.A.T., S.L., J.D.M., E.J.B.d.C., D.J.F., D.W.S.), Department of Physiology (D.W.S), Department of Pharmacology (D.J.F.), and Department of Medicine (S.L., E.J.B.d.C.), Augusta University, GA
| | - David J Fulton
- From the Vascular Biology Center (J.A.T., S.L., J.D.M., E.J.B.d.C., D.J.F., D.W.S.), Department of Physiology (D.W.S), Department of Pharmacology (D.J.F.), and Department of Medicine (S.L., E.J.B.d.C.), Augusta University, GA
| | - David W Stepp
- From the Vascular Biology Center (J.A.T., S.L., J.D.M., E.J.B.d.C., D.J.F., D.W.S.), Department of Physiology (D.W.S), Department of Pharmacology (D.J.F.), and Department of Medicine (S.L., E.J.B.d.C.), Augusta University, GA.
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22
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Shekhar S, Wang S, Mims PN, Gonzalez-Fernandez E, Zhang C, He X, Liu CY, Lv W, Wang Y, Huang J, Fan F. Impaired Cerebral Autoregulation-A Common Neurovascular Pathway in Diabetes may Play a Critical Role in Diabetes-Related Alzheimer's Disease. CURRENT RESEARCH IN DIABETES & OBESITY JOURNAL 2017; 2:555587. [PMID: 28825056 PMCID: PMC5559201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Alzheimer's disease (AD) is the leading cause of progressive degenerative dementia. The hallmark pathological features include beta amyloid deposition and neurofibrillary tangles. There has been a strong association of AD with Diabetes (DM) based on human studies and animal experiments. The hallmark features of AD seem to have an exaggerated presence in AD with DM, especially type 2 diabetes (T2D). In addition, insulin resistance is a common feature in both diseases and as such AD has been called type 3 diabetes. Furthermore, impairment of cerebral autoregulation has been reported in both animal and human diabetic subjects. Cerebral vascular impairment has also been implicated in the pathophysiology of AD. There is an urgent need to develop animal models of AD and DM to explore the neuropathological mechanisms of these disease and utilize such models to develop treatment strategies.
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Affiliation(s)
- Shashank Shekhar
- Department of Neurology, University of Mississippi Medical Center, USA,Institute of Clinical Medicine, University of Turku, Finland
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, USA
| | - Paige N Mims
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, USA
| | | | - Chao Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, USA,Department of Urology, Fudan University, China
| | - Xiaochen He
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, USA
| | - Catherine Y Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, USA
| | - Wenshan Lv
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, USA,Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, China
| | - Yangang Wang
- Department of Endocrinology and Metabolism, The Affiliated Hospital of Qingdao University, China
| | - Juebin Huang
- Department of Neurology, University of Mississippi Medical Center, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, USA,Corresponding author: Fan Fan, Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, USA, Tel: 601-984-2320; Fax: 601-984-1637;
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23
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Hardigan T, Hernandez C, Ward R, Hoda MN, Ergul A. TLR2 knockout protects against diabetes-mediated changes in cerebral perfusion and cognitive deficits. Am J Physiol Regul Integr Comp Physiol 2017; 312:R927-R937. [PMID: 28336553 DOI: 10.1152/ajpregu.00482.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 01/25/2017] [Accepted: 02/17/2017] [Indexed: 12/29/2022]
Abstract
The risk of cognitive decline in diabetes (Type 1 and Type 2) is significantly greater compared with normoglycemic patients, and the risk of developing dementia in diabetic patients is doubled. The etiology for this is likely multifactorial, but one mechanism that has gained increasing attention is decreased cerebral perfusion as a result of cerebrovascular dysfunction. The innate immune system has been shown to play a role in diabetic vascular complications, notably through the Toll-like receptor (TLR)-stimulated release of proinflammatory cytokines and chemokines that lead to vascular damage. TLR2 has been implicated in playing a crucial role in the development of diabetic microvascular complications, such as nephropathy, and thus, we hypothesized that TLR2-mediated cerebrovascular dysfunction leads to decreased cerebral blood flow (CBF) and cognitive impairment in diabetes. Knockout of TLR2 conferred protection from impaired CBF in early-stage diabetes and from hyperperfusion in long-term diabetes, prevented the development of endothelium-dependent vascular dysfunction in diabetes, created a hyperactive and anxiolytic phenotype, and protected against diabetes-induced impairment of long-term hippocampal and prefrontal cortex-mediated fear learning. In conclusion, these findings support the involvement of TLR2 in the pathogenesis of diabetic vascular disease and cognitive impairment.
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Affiliation(s)
- Trevor Hardigan
- Department of Physiology, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Caterina Hernandez
- Department of Pharmacology and Toxicology, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia.,Department of Small Animal Behavior Core Facility, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - Rebecca Ward
- Department of Neuroscience, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia
| | - M Nasrul Hoda
- Department of Medical Laboratory, Imaging and Radiologic Sciences, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia.,Department of Neurology, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia.,Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia; and
| | - Adviye Ergul
- Department of Physiology, University of Georgia, Medical College of Georgia, Augusta University, Augusta, Georgia; .,Charlie Norwood Veterans Administration Medical Center, Augusta, Georgia
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24
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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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Coucha M, Abdelsaid M, Li W, Johnson MH, Orfi L, El-Remessy AB, Fagan SC, Ergul A. Nox4 contributes to the hypoxia-mediated regulation of actin cytoskeleton in cerebrovascular smooth muscle. Life Sci 2016; 163:46-54. [PMID: 27558234 DOI: 10.1016/j.lfs.2016.08.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/12/2016] [Accepted: 08/19/2016] [Indexed: 11/29/2022]
Abstract
UNLABELLED Ischemia/reperfusion and the resulting oxidative/nitrative stress impair cerebral myogenic tone via actin depolymerization. While it is known that NADPH oxidase (Nox) family is a major source of vascular oxidative stress; the extent and mechanisms by which Nox activation contributes to actin depolymerization, and equally important, the relative role of Nox isoforms in this response is not clear. AIM To determine the role of Nox4 in hypoxia-mediated actin depolymerization and myogenic-tone impairment in cerebral vascular smooth muscle. MAIN METHODS Control and Nox4 deficient (siRNA knock-down) human brain vascular smooth muscle cells (HBVSMC) were exposed to 30-min hypoxia/45-min reoxygenation. Nox2, Nox4, inducible and neuronal nitric oxide synthase (iNOS and nNOS) and nitrotyrosine levels as well as F:G actin were determined. Myogenic-tone was measured using pressurized arteriography in middle cerebral artery isolated from rats subjected to sham, 30-min ischemia/45-min reperfusion or ex-vivo oxygen glucose deprivation in the presence and absence of Nox inhibitors. RESULTS Nox4 and iNOS expression were significantly upregulated following hypoxia or ischemia/reperfusion. Hypoxia augmented nitrotyrosine levels while reducing F actin. These effects were nullified by inhibiting nitration with epicatechin or pharmacological or molecular inhibition of Nox4. Ischemia/reperfusion impaired myogenic-tone, which was restored by the selective inhibition of Nox4. CONCLUSION Nox4 activation in VSMCs contributes to actin depolymerization after hypoxia, which could be the underlying mechanism for myogenic-tone impairment following ischemia/reperfusion.
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Affiliation(s)
- Maha Coucha
- Charlie Norwood VA Medical Center, Augusta University, United States; Departments of Physiology, Augusta University, United States; Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, United States
| | - Mohammed Abdelsaid
- Charlie Norwood VA Medical Center, Augusta University, United States; Departments of Physiology, Augusta University, United States
| | - Weiguo Li
- Charlie Norwood VA Medical Center, Augusta University, United States; Departments of Physiology, Augusta University, United States
| | | | | | - Azza B El-Remessy
- Charlie Norwood VA Medical Center, Augusta University, United States; Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, United States
| | - Susan C Fagan
- Charlie Norwood VA Medical Center, Augusta University, United States; Departments of Neurology, Augusta University, United States; Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, United States
| | - Adviye Ergul
- Charlie Norwood VA Medical Center, Augusta University, United States; Departments of Physiology, Augusta University, United States; Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA, United States.
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Sauvé M, Hui SK, Dinh DD, Foltz WD, Momen A, Nedospasov SA, Offermanns S, Husain M, Kroetsch JT, Lidington D, Bolz SS. Tumor Necrosis Factor/Sphingosine-1-Phosphate Signaling Augments Resistance Artery Myogenic Tone in Diabetes. Diabetes 2016; 65:1916-28. [PMID: 27207546 DOI: 10.2337/db15-1450] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 03/23/2016] [Indexed: 11/13/2022]
Abstract
Diabetes strongly associates with microvascular complications that ultimately promote multiorgan failure. Altered myogenic responsiveness compromises tissue perfusion, aggravates hypertension, and sets the stage for later permanent structural changes to the microcirculation. We demonstrate that skeletal muscle resistance arteries isolated from patients with diabetes have augmented myogenic tone, despite reasonable blood glucose control. To understand the mechanisms, we titrated a standard diabetes mouse model (high-fat diet plus streptozotocin [HFD/STZ]) to induce a mild increase in blood glucose levels. HFD/STZ treatment induced a progressive myogenic tone augmentation in mesenteric and olfactory cerebral arteries; neither HFD nor STZ alone had an effect on blood glucose or resistance artery myogenic tone. Using gene deletion models that eliminate tumor necrosis factor (TNF) or sphingosine kinase 1, we demonstrate that vascular smooth muscle cell TNF drives the elevation of myogenic tone via enhanced sphingosine-1-phosphate (S1P) signaling. Therapeutically antagonizing TNF (etanercept) or S1P (JTE013) signaling corrects this defect. Our investigation concludes that vascular smooth muscle cell TNF augments resistance artery myogenic vasoconstriction in a diabetes model that induces a small elevation of blood glucose. Our data demonstrate that microvascular reactivity is an early disease marker and advocate establishing therapies that strategically target the microcirculation.
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Affiliation(s)
- Meghan Sauvé
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Sonya K Hui
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada Toronto Centre for Microvascular Medicine, University of Toronto at the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Danny D Dinh
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Warren D Foltz
- Spatio-Temporal Targeting and Amplification of Radiation Response Innovation Centre, Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Abdul Momen
- Division of Cell and Molecular Biology, Toronto General Hospital Research Institute, Toronto, Ontario, Canada
| | - Sergei A Nedospasov
- Engelhardt Institute of Molecular Biology and Lomonosov Moscow State University, Moscow, Russia
| | - Stefan Offermanns
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Mansoor Husain
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada Division of Cell and Molecular Biology, Toronto General Hospital Research Institute, Toronto, Ontario, Canada Department of Medicine, University of Toronto, Toronto, Ontario, Canada Heart and Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, University of Toronto, Toronto, Ontario, Canada
| | - Jeffrey T Kroetsch
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Darcy Lidington
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada Toronto Centre for Microvascular Medicine, University of Toronto at the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Steffen-Sebastian Bolz
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada Toronto Centre for Microvascular Medicine, University of Toronto at the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada Heart and Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, University of Toronto, Toronto, Ontario, Canada Keenan Research Centre at the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
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Hardigan T, Yasir A, Abdelsaid M, Coucha M, El-Shaffey S, Li W, Johnson MH, Ergul A. Linagliptin treatment improves cerebrovascular function and remodeling and restores reduced cerebral perfusion in Type 2 diabetes. Am J Physiol Regul Integr Comp Physiol 2016; 311:R466-77. [PMID: 27357799 DOI: 10.1152/ajpregu.00057.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/24/2016] [Indexed: 12/20/2022]
Abstract
The antihyperglycemic agent linagliptin, a dipeptidyl peptidase-4 (DPP-IV) inhibitor, has been shown to reduce inflammation and improve endothelial cell function. In this study, we hypothesized that DPP-IV inhibition with linagliptin would improve impaired cerebral perfusion in diabetic rats, as well as improve insulin-induced cerebrovascular relaxation and reverse pathological cerebrovascular remodeling. We further postulated that these changes would lead to a subsequent improvement of cognitive function. Male Type-2 diabetic and nondiabetic Goto-Kakizaki rats were treated with linagliptin for 4 wk, and blood glucose and DPP-IV plasma levels were assessed. Cerebral perfusion was assessed after treatment using laser-Doppler imaging, and dose response to insulin (10(-13) M-10(-6) M) in middle cerebral arteries was tested on a pressurized arteriograph. The impact of DPP-IV inhibition on diabetic cerebrovascular remodeling was assessed over a physiologically relevant pressure range, and changes in short-term hippocampus-dependent learning were observed using a novel object recognition test. Linagliptin lowered DPP-IV activity but did not change blood glucose or insulin levels in diabetes. Insulin-mediated vascular relaxation and cerebral perfusion were improved in the diabetic rats with linagliptin treatment. Indices of diabetic vascular remodeling, such as increased cross-sectional area, media thickness, and wall-to-lumen ratio, were also ameliorated; however, improvements in short-term hippocampal-dependent learning were not observed. The present study provides evidence that linagliptin treatment improves cerebrovascular dysfunction and remodeling in a Type 2 model of diabetes independent of glycemic control. This has important implications in diabetic patients who are predisposed to the development of cerebrovascular complications, such as stroke and cognitive impairment.
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Affiliation(s)
- Trevor Hardigan
- Department of Physiology, Medical College of Georgia, Augusta, Georgia; and
| | - Abdul Yasir
- Department of Physiology, Medical College of Georgia, Augusta, Georgia; and
| | - Mohammed Abdelsaid
- Charlie Norwood Veterans Administration Medical Center, Augusta, Georgia; Department of Physiology, Medical College of Georgia, Augusta, Georgia; and
| | - Maha Coucha
- Charlie Norwood Veterans Administration Medical Center, Augusta, Georgia; Department of Physiology, Medical College of Georgia, Augusta, Georgia; and
| | - Sally El-Shaffey
- Department of Physiology, Medical College of Georgia, Augusta, Georgia; and
| | - Weiguo Li
- Charlie Norwood Veterans Administration Medical Center, Augusta, Georgia; Department of Physiology, Medical College of Georgia, Augusta, Georgia; and
| | - Maribeth H Johnson
- Department of Biostatistics, The Graduate School at Augusta University, Augusta, Georgia
| | - Adviye Ergul
- Charlie Norwood Veterans Administration Medical Center, Augusta, Georgia; Department of Physiology, Medical College of Georgia, Augusta, Georgia; and
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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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Ma S, Zhao H, Ji X, Luo Y. Peripheral to central: Organ interactions in stroke pathophysiology. Exp Neurol 2015; 272:41-9. [PMID: 26054885 DOI: 10.1016/j.expneurol.2015.05.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/20/2015] [Accepted: 05/23/2015] [Indexed: 12/27/2022]
Abstract
Stroke is associated with a high risk of disability and mortality, and with the exception of recombinant tissue-type plasminogen activator for acute stroke, most treatments have proven ineffective. Clinical translation of promising experimental therapeutics is limited by inadequate stroke models and a lack of understanding of the mechanisms underlying acute stroke and how they affect outcome. Bidirectional communication between the ischemic brain and peripheral immune system modulates stroke progression and tissue repair, while epidemiological studies have provided evidence of an association between organ dysfunction and stroke risk. This crosstalk can determine the fate of stroke patients and must be taken into consideration when investigating the pathophysiological mechanisms and therapeutic options for stroke. This review summarizes the current evidence for interactions between the brain and other organs in stroke pathophysiology in basic and clinic studies, and discusses the role of these interactions in the progression and outcome of stroke and how they can direct the development of more effective treatment strategies.
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Affiliation(s)
- Shubei Ma
- Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, Beijing 100053, China
| | - Haiping Zhao
- Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, Beijing 100053, China
| | - Xunming Ji
- Department of Neurosurgery, Xuanwu Hospital of Capital Medical University, Beijing 100053, China.
| | - Yumin Luo
- Cerebrovascular Diseases Research Institute, Xuanwu Hospital of Capital Medical University, Beijing 100053, China; Center of Stroke, Beijing Institute for Brain Disorders, Beijing 100053, China.
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30
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Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
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Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Abstract
SIGNIFICANCE The brain has high energetic requirements and is therefore highly dependent on adequate cerebral blood supply. To compensate for dangerous fluctuations in cerebral perfusion, the circulation of the brain has evolved intrinsic safeguarding measures. RECENT ADVANCES AND CRITICAL ISSUES The vascular network of the brain incorporates a high degree of redundancy, allowing the redirection and redistribution of blood flow in the event of vascular occlusion. Furthermore, active responses such as cerebral autoregulation, which acts to maintain constant cerebral blood flow in response to changing blood pressure, and functional hyperemia, which couples blood supply with synaptic activity, allow the brain to maintain adequate cerebral perfusion in the face of varying supply or demand. In the presence of stroke risk factors, such as hypertension and diabetes, these protective processes are impaired and the susceptibility of the brain to ischemic injury is increased. One potential mechanism for the increased injury is that collateral flow arising from the normally perfused brain and supplying blood flow to the ischemic region is suppressed, resulting in more severe ischemia. FUTURE DIRECTIONS Approaches to support collateral flow may ameliorate the outcome of focal cerebral ischemia by rescuing cerebral perfusion in potentially viable regions of the ischemic territory.
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Affiliation(s)
- Katherine Jackman
- Brain and Mind Research Institute, Weill Cornell Medical College , New York, New York
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Coucha M, Li W, Hafez S, Abdelsaid M, Johnson MH, Fagan SC, Ergul A. SOD1 overexpression prevents acute hyperglycemia-induced cerebral myogenic dysfunction: relevance to contralateral hemisphere and stroke outcomes. Am J Physiol Heart Circ Physiol 2014; 308:H456-66. [PMID: 25552308 DOI: 10.1152/ajpheart.00321.2014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Admission hyperglycemia (HG) amplifies vascular injury and neurological deficits in acute ischemic stroke, but the mechanisms remain controversial. We recently reported that ischemia-reperfusion (I/R) injury impairs the myogenic response in both hemispheres via increased nitration. However, whether HG amplifies contralateral myogenic dysfunction and whether loss of tone in the contralateral hemisphere contributes to stroke outcomes remain to be determined. Our hypothesis was that contralateral myogenic dysfunction worsens stroke outcomes after acute hyperglycemic stroke in an oxidative stress-dependent manner. Male wild-type or SOD1 transgenic rats were injected with saline or 40% glucose solution 10 min before surgery and then subjected to 30 min of ischemia/45 min or 24 h of reperfusion. In another set of animals (n = 5), SOD1 was overexpressed only in the contralateral hemisphere by stereotaxic adenovirus injection 2-3 wk before I/R. Myogenic tone and neurovascular outcomes were determined. HG exacerbated myogenic dysfunction in contralateral side only, which was associated with infarct size expansion, increased edema, and more pronounced neurological deficit. Global and selective SOD1 overexpression restored myogenic reactivity in ipsilateral and contralateral sides, respectively, and enhanced neurovascular outcomes. In conclusion, our results show that SOD1 overexpression nullified the detrimental effects of HG on myogenic tone and stroke outcomes and that the contralateral hemisphere may be a novel target for the management of acute hyperglycemic stroke.
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Affiliation(s)
- Maha Coucha
- Department of Physiology, Georgia Regents University, Augusta, Georgia
| | - Weiguo Li
- Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; Department of Physiology, Georgia Regents University, Augusta, Georgia
| | - Sherif Hafez
- Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, Georgia
| | - Mohammed Abdelsaid
- Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; Department of Physiology, Georgia Regents University, Augusta, Georgia
| | - Maribeth H Johnson
- Department of Biostatistics, Georgia Regents University, Augusta, Georgia
| | - Susan C Fagan
- Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; Department of Neurology, Georgia Regents University, Augusta, Georgia; and Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, Georgia
| | - Adviye Ergul
- Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia; Department of Physiology, Georgia Regents University, Augusta, Georgia; Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, Georgia
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Abdelsaid M, Coucha M, Ergul A. Cerebrovasculoprotective effects of azilsartan medoxomil in diabetes. Transl Res 2014; 164:424-32. [PMID: 24999268 PMCID: PMC4250409 DOI: 10.1016/j.trsl.2014.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 06/11/2014] [Indexed: 01/13/2023]
Abstract
We have shown that Goto-Kakizaki (GK) rats, a lean model of type 2 diabetes, develop significant cerebrovascular remodeling by the age of 18 weeks, which is characterized by increased media thickness and matrix deposition. Although early glycemic control prevents diabetes-mediated remodeling of the cerebrovasculature, whether the remodeling can be reversed is unknown. Given that angiotensin II type 1 receptor blockers reverse pathologic vascular remodeling and function independent of changes in blood pressure in other vascular beds, we hypothesized that azilsartan medoxomil, a new angiotensin II type 1 receptor blocker, is vasculoprotective by preventing and reversing cerebrovascular remodeling in diabetes. Control Wistar and diabetic GK rats (n = 6-8 per group) were treated with vehicle (water) or azilsartan medoxomil (3 mg/kg/d) from the age of 14 to 18 or 18 to 22 weeks before or after vascular remodeling is established, respectively. Blood glucose and blood pressure were monitored and middle cerebral artery structure and function were evaluated using pressurized arteriography. Blood glucose was higher in GK rats compared with Wistar rats. Azilsartan treatment lowered blood glucose in diabetic animals with no effect on blood pressure. Diabetic animals exhibited lower myogenic tone, increased wall thickness, and cross-sectional area compared with control group animals, which were corrected by azilsartan treatment when started at the onset of diabetes or later after vascular remodeling is established. Azilsartan medoxomil offers preventive and therapeutic vasculoprotection in diabetes-induced cerebrovascular remodeling and myogenic dysfunction and this is independent of blood pressure.
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Affiliation(s)
- Mohammed Abdelsaid
- Charlie Norwood Veterans Administration Medical Center, Georgia Regents University, Augusta, GA; Department of Physiology, Georgia Regents University, Augusta, GA
| | - Maha Coucha
- Department of Physiology, Georgia Regents University, Augusta, GA
| | - Adviye Ergul
- Charlie Norwood Veterans Administration Medical Center, Georgia Regents University, Augusta, GA; Department of Physiology, Georgia Regents University, Augusta, GA.
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Coucha M, Li W, Johnson MH, Fagan SC, Ergul A. Reply to "Letter to the editor: 'Targeting cerebrovascular myogenic dysfunction in stroke'". Am J Physiol Heart Circ Physiol 2014; 306:H1483. [PMID: 24833734 DOI: 10.1152/ajpheart.00207.2014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Maha Coucha
- Department of Physiology, Georgia Regents University, Augusta, Georgia
| | - Weiguo Li
- Department of Physiology, Georgia Regents University, Augusta, Georgia; Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia
| | - Maribeth H Johnson
- Department of Biostatistics, Georgia Regents University, Augusta, Georgia
| | - Susan C Fagan
- Department of Neurology, Georgia Regents University, Augusta, Georgia; Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia, Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, Georgia
| | - Adviye Ergul
- Department of Physiology, Georgia Regents University, Augusta, Georgia; Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia,
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Ergul A, Abdelsaid M, Fouda AY, Fagan SC. Cerebral neovascularization in diabetes: implications for stroke recovery and beyond. J Cereb Blood Flow Metab 2014; 34:553-63. [PMID: 24496174 PMCID: PMC3982092 DOI: 10.1038/jcbfm.2014.18] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 12/20/2013] [Accepted: 12/30/2013] [Indexed: 01/30/2023]
Abstract
Neovascularization is an innate physiologic response by which tissues respond to various stimuli through collateral remodeling (arteriogenesis) and new vessel formation from existing vessels (angiogenesis) or from endothelial progenitor cells (vasculogenesis). Diabetes has a major impact on the neovascularization process but the response varies between different organ systems. While excessive angiogenesis complicates diabetic retinopathy, impaired neovascularization contributes to coronary and peripheral complications of diabetes. How diabetes influences cerebral neovascularization remained unresolved until recently. Diabetes is also a major risk factor for stroke and poor recovery after stroke. In this review, we discuss the impact of diabetes, stroke, and diabetic stroke on cerebral neovascularization, explore potential mechanisms involved in diabetes-mediated neovascularization as well as the effects of the diabetic milieu on poststroke neovascularization and recovery, and finally discuss the clinical implications of these effects.
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Affiliation(s)
- Adviye Ergul
- 1] Charlie Norwood VA Medical Center, Augusta, Georgia, USA [2] Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA [3] Center for Pharmacy and Experimental Therapeutics, Medical College of Georgia and University of Georgia College of Pharmacy, Augusta, Georgia, USA
| | - Mohammed Abdelsaid
- 1] Charlie Norwood VA Medical Center, Augusta, Georgia, USA [2] Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
| | - Abdelrahman Y Fouda
- 1] Charlie Norwood VA Medical Center, Augusta, Georgia, USA [2] Center for Pharmacy and Experimental Therapeutics, Medical College of Georgia and University of Georgia College of Pharmacy, Augusta, Georgia, USA
| | - Susan C Fagan
- 1] Charlie Norwood VA Medical Center, Augusta, Georgia, USA [2] Center for Pharmacy and Experimental Therapeutics, Medical College of Georgia and University of Georgia College of Pharmacy, Augusta, Georgia, USA [3] Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
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36
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Hyperglycemia, acute ischemic stroke, and thrombolytic therapy. Transl Stroke Res 2014; 5:442-453. [PMID: 24619488 DOI: 10.1007/s12975-014-0336-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 02/25/2014] [Accepted: 02/27/2014] [Indexed: 01/04/2023]
Abstract
Ischemic stroke is a leading cause of disability and is considered now the fourth leading cause of death. Many clinical trials have shown that stroke patients with acute elevation in blood glucose at onset of stroke suffer worse functional outcomes, longer in-hospital stay, and higher mortality rates. The only therapeutic hope for these patients is the rapid restoration of blood flow to the ischemic tissue through intravenous administration of the only currently proven effective therapy, tissue plasminogen activator (tPA). However, even this option is associated with the increased risk of intracerebral hemorrhage. Nonetheless, the underlying mechanisms through which hyperglycemia (HG) and tPA worsen the neurovascular injury after stroke are not fully understood. Accordingly, this review summarizes the latest updates and recommendations about the management of HG and coadministration of tPA in a clinical setting while focusing more on the various experimental models studying (1) the effect of HG on stroke outcomes, (2) the potential mechanisms involved in worsening the neurovascular injury, (3) the different therapeutic strategies employed to ameliorate the injury, and finally, (4) the interaction between HG and tPA. Developing therapeutic strategies to reduce the hemorrhage risk with tPA in hyperglycemic setting is of great clinical importance. This can best be achieved by conducting robust preclinical studies evaluating the interaction between tPA and other therapeutics in order to develop potential therapeutic strategies with high translational impact.
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Abdelsaid M, Ma H, Coucha M, Ergul A. Late dual endothelin receptor blockade with bosentan restores impaired cerebrovascular function in diabetes. Life Sci 2014; 118:263-7. [PMID: 24434796 DOI: 10.1016/j.lfs.2013.12.231] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 12/16/2013] [Accepted: 12/31/2013] [Indexed: 01/21/2023]
Abstract
AIMS Up-regulation of the endothelin (ET) system in type-2 diabetes increases contraction and decreases relaxation in basilar artery. We showed that 1) ET-receptor antagonism prevents diabetes-mediated cerebrovascular dysfunction; and 2) glycemic control prevents activation of the ET-system in diabetes. Here, our goal is to determine whether and to what extent glycemic control or ET-receptor antagonism reverses established cerebrovascular dysfunction in diabetes. MAIN METHODS Non-obese type-2 diabetic Goto-Kakizaki rats were administered either vehicle, metformin (300 mg/kg/day) or dual ET-receptor antagonist bosentan (100mg/kg) for 4-weeks starting at 18-weeks after established cerebrovascular dysfunction (n=5-6/group). Control group included vehicle-treated aged-matched Wistar rats. Blood glucose and pressure were monitored weekly. At termination, basilar arteries were collected and cumulative dose-response curves to ET-1 (0.1-500 nM), 5-HT (1-1000 nM) and acetylcholine (Ach, 0.1 nM-5 μM) were studied by wire myograph. Middle cerebral artery (MCA) myogenic reactivity and tone were measured using pressurized arteriograph. KEY FINDINGS There was no difference in ET-1 and 5-HT-mediated constrictions. Endothelium-dependent relaxation was impaired in diabetes. Bosentan improved sensitivity to Ach as well as the maximum relaxation. Myogenic-tone is decreased over the course of the disease. Both treatments improved the ability of MCAs to develop tone at 80 mm Hg and only bosentan improved the tone at higher pressures. SIGNIFICANCE These results suggest that contractile response is not affected by glycemic control or ET-receptor antagonism. Meanwhile, dual ET-receptor blockade is effective in partially improving endothelium-dependent relaxation and myogenic response in a blood pressure-independent manner even after established cerebrovascular dysfunction and offers therapeutic potential.
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Affiliation(s)
- Mohammed Abdelsaid
- Charlie Norwood Veterans Administration Medical Center, University of Georgia College of Pharmacy, USA; Department of Physiology, Georgia Regents University, Augusta, GA, USA
| | - Handong Ma
- Charlie Norwood Veterans Administration Medical Center, University of Georgia College of Pharmacy, USA; Department of Physiology, Georgia Regents University, Augusta, GA, USA
| | - Maha Coucha
- Department of Physiology, Georgia Regents University, Augusta, GA, USA
| | - Adviye Ergul
- Charlie Norwood Veterans Administration Medical Center, University of Georgia College of Pharmacy, USA; Center for Pharmacy and Experimental Therapeutics, University of Georgia College of Pharmacy, USA; Department of Physiology, Georgia Regents University, Augusta, GA, USA.
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Comparative analysis of the neurovascular injury and functional outcomes in experimental stroke models in diabetic Goto-Kakizaki rats. Brain Res 2013; 1541:106-14. [PMID: 24144674 DOI: 10.1016/j.brainres.2013.10.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/09/2013] [Accepted: 10/11/2013] [Indexed: 12/25/2022]
Abstract
Diabetes worsens functional outcome and is associated with greater hemorrhagic transformation (HT) after ischemic stroke. We have shown that diabetic Goto-Kakizaki (GK) rats develop greater HT and neurological deficit despite smaller infarcts after transient middle cerebral artery occlusion (MCAO) with the suture model. However, the impact of (1) the duration of ischemia/reperfusion (I/R); (2) the method of ischemia; and (3) acute glycemic control on neurovascular injury and functional outcome in diabetic stroke remained unanswered. Wistar and GK rats were subjected to variable MCAO by suture or embolus occlusion. A group of GK rats were treated with insulin or metformin before stroke with suture occlusion. In all groups, infarct size, edema, HT occurrence and severity, and functional outcome were measured. Infarct size at 24h was smaller in GK rats with both suture and embolic MCAO, but expanded with longer reperfusion period. Edema and HT were increased in GK rats after 90min and 3h occlusion with the suture model, but not in the embolic MCAO. Neurological deficit was greater in diabetic rats. These findings suggest that diabetes accelerates the development of HT and amplifies vascular damage in the suture model where blood flow is rapidly reestablished. Acute metformin treatment worsened the infarct size, HT, and behavior outcome, whereas insulin treatment showed a protective effect. These results suggest that the impact of ischemia/reperfusion on neurovascular injury and functional outcome especially in disease models needs to be fully characterized using different models of stroke to model the human condition.
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Coucha M, Li W, Johnson MH, Fagan SC, Ergul A. Protein nitration impairs the myogenic tone of rat middle cerebral arteries in both ischemic and nonischemic hemispheres after ischemic stroke. Am J Physiol Heart Circ Physiol 2013; 305:H1726-35. [PMID: 24097431 DOI: 10.1152/ajpheart.00535.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The myogenic response is crucial for maintaining vascular resistance to achieve constant perfusion during pressure fluctuations. Reduced cerebral blood flow has been reported in ischemic and nonischemic hemispheres after stroke. Ischemia-reperfusion injury and the resulting oxidative stress impair myogenic responses in the ischemic hemisphere. Yet, the mechanism by which ischemia-reperfusion affects the nonischemic side is still undetermined. The goal of the present study was to determine the effect of ischemia-reperfusion injury on the myogenic reactivity of cerebral vessels from both hemispheres and whether protein nitration due to excess peroxynitrite production is the underlying mechanism of loss of tone. Male Wistar rats were subjected to sham operation or 30-min middle cerebral artery occlusion/45-min reperfusion. Rats were administered saline, the peroxynitrite decomposition catalyst 5,10,15,20-tetrakis(4-sulfonatophenyl)prophyrinato iron (III), or the nitration inhibitor epicatechin at reperfusion. Middle cerebral arteries isolated from another set of control rats were exposed to ex vivo oxygen-glucose deprivation with and without glycoprotein 91 tat (NADPH oxidase inhibitor) or N(ω)-nitro-l-arginine methyl ester. Myogenic tone and nitrotyrosine levels were determined. Ischemia-reperfusion injury impaired the myogenic tone of vessels in both hemispheres compared with the sham group (P < 0.001). Vessels exposed to ex vivo oxygen-glucose deprivation experienced a similar loss of myogenic tone. Inhibition of peroxynitrite parent radicals significantly improved the myogenic tone. Peroxynitrite scavenging or inhibition of nitration improved the myogenic tone of vessels from ischemic (P < 0.001 and P < 0.05, respectively) and nonischemic (P < 0.01 and P < 0.05, respectively) hemispheres. Nitration was significantly increased in both hemispheres versus the sham group and was normalized with epicatechin treatment. In conclusion, ischemia-reperfusion injury impairs vessel reactivity in both hemispheres via nitration. We suggest that sham operation rather than the nonischemic side should be used as a control in preclinical stroke studies.
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Affiliation(s)
- Maha Coucha
- Department of Physiology, Georgia Regents University, Augusta, Georgia
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Prakash R, Li W, Qu Z, Johnson MA, Fagan SC, Ergul A. Vascularization pattern after ischemic stroke is different in control versus diabetic rats: relevance to stroke recovery. Stroke 2013; 44:2875-82. [PMID: 23920018 DOI: 10.1161/strokeaha.113.001660] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND AND PURPOSE Pre-existing diabetes mellitus worsens brain functionality in ischemic stroke. We have previously shown that type 2 diabetic rats exhibit enhanced dysfunctional cerebral neovascularization and when these rats are subjected to cerebral ischemic reperfusion injury develop hemorrhagic transformation and greater neurological deficits. However, our knowledge of vascular and functional plasticity during the recovery phase of diabetic stroke is limited. This study tested the hypothesis that vascular repair is impaired in the poststroke period in diabetes mellitus, and this is associated with poor sensorimotor and cognitive function. We further hypothesized that glycemic control prevents impaired vascularization and improves functional outcome in diabetes mellitus. METHODS Vascularization was assessed in the ipsilateral and contralateral hemispheres in control, diabetes mellitus and diabetes mellitus plus metformin groups 14 days after ischemic reperfusion injury, as well as in respective sham controls. Three-dimensional reconstruction of the fluorescein isothiocyanate (FITC)-stained vasculature was achieved by confocal microscopy, and stereological parameters, including vascular volume and surface area, were measured. Astrogliosis was determined by glial fibrillary acidic protein staining. The relative rates of sensorimotor recovery, cognitive decline, and spontaneous activity were assessed. RESULTS Vascular density in the peri-infarct area was significantly reduced in diabetes mellitus, whereas there was reparative neovascularization in control rats. Astroglial swelling and reactivity were more pronounced in diabetic stroke compared with control stroke. Diabetes mellitus blunted sensorimotor recovery and also exacerbated anxiety-like symptoms and cognitive deficits. Glycemic control started after stroke partially prevented these changes. CONCLUSIONS Diabetes mellitus impairs poststroke reparative neovascularization and impedes the recovery. Glycemic control after stroke can improve neurovascular repair and improve functional outcome.
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Affiliation(s)
- Roshini Prakash
- From the Department of Physiology, Charlie Norwood Veterans Administration Medical Center, Augusta, GA (R.P., W.L., S.C.F., A.E.); Program in Clinical and Experimental Therapeutics, University of Georgia College of Pharmacy, Augusta, GA (R.P., S.C.F., A.E.); and Departments of Physiology (W.L., Z.Q., A.E.), and Biostatistics (M.A.J.), Georgia Regents University, Augusta, GA
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Li W, Prakash R, Chawla D, Du W, Didion SP, Filosa JA, Zhang Q, Brann DW, Lima VV, Tostes RC, Ergul A. Early effects of high-fat diet on neurovascular function and focal ischemic brain injury. Am J Physiol Regul Integr Comp Physiol 2013; 304:R1001-8. [PMID: 23576615 DOI: 10.1152/ajpregu.00523.2012] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Obesity is a risk factor for stroke, but the early effects of high-fat diet (HFD) on neurovascular function and ischemic stroke outcomes remain unclear. The goal of this study was to test the hypotheses that HFD beginning early in life 1) impairs neurovascular coupling, 2) causes cerebrovascular dysfunction, and 3) worsens short-term outcomes after cerebral ischemia. Functional hyperemia and parenchymal arteriole (PA) reactivity were measured in rats after 8 wk of HFD. The effect of HFD on basilar artery function after middle cerebral artery occlusion (MCAO) and associated O-GlcNAcylation were assessed. Neuronal cell death, infarct size, hemorrhagic transformation (HT) frequency/severity, and neurological deficit were evaluated after global ischemia and transient MCAO. HFD caused a 10% increase in body weight and doubled adiposity without a change in lipid profile, blood glucose, and blood pressure. Functional hyperemia and PA relaxation were decreased with HFD. Basilar arteries from stroked HFD rats were more sensitive to contractile factors, and acetylcholine-mediated relaxation was impaired. Vascular O-GlcNAcylated protein content was increased with HFD. This group also showed greater mortality rate, infarct volume, HT occurrence rate, and HT severity and poor functional outcome compared with the control diet group. These results indicate that HFD negatively affects neurovascular coupling and cerebrovascular function even in the absence of dyslipidemia. These early cerebrovascular changes may be the cause of greater cerebral injury and poor outcomes of stroke in these animals.
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Affiliation(s)
- Weiguo Li
- Charlie Norwood Department of Veterans Affairs Medical Center, Augusta, GA, USA
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Cerebral neovascularization and remodeling patterns in two different models of type 2 diabetes. PLoS One 2013; 8:e56264. [PMID: 23441170 PMCID: PMC3575336 DOI: 10.1371/journal.pone.0056264] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/07/2013] [Indexed: 11/19/2022] Open
Abstract
We previously reported intense pial cerebral collateralization and arteriogenesis in a mild and lean model of type 2 diabetes (T2D), Goto-Kakizaki (GK) rats. Increased cerebral neovascularization differed regionally and was associated with poor vessel wall maturity. Building upon these findings, the goals of this study were to determine whether a) glycemic control prevents this erratic cerebral neovascularization in the GK model, and b) this pathological neovascularization pattern occurs in Lepr(db/db) model, which is the most commonly used model of T2D for studies involving cerebral complications of diabetes. Vascular volume, surface area and structural parameters including microvessel/macrovessel ratio, non-FITC (fluorescein) perfusing vessel abundance, vessel tortuosity, and branch density were measured by 3D reconstruction of FITC stained vasculature in GK rats or Lepr(db/db) mice. GK rats exhibited an increase in all of these parameters, which were prevented by glycemic control with metformin. In Lepr(db/db) mice, microvascular density was increased but there was no change in nonFITC-perfusing vessels. Increased PA branch density was associated with reduced branch diameter. These results suggest that T2D leads to cerebral neovascularization and remodeling but some structural characteristics of newly formed vessels differ between these models of T2D. The prevention of dysfunctional cerebral neovascularization by early glucose control suggests that hyperglycemia is a mediator of this response.
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Kelly-Cobbs AI, Prakash R, Li W, Pillai B, Hafez S, Coucha M, Johnson MH, Ogbi SN, Fagan SC, Ergul A. Targets of vascular protection in acute ischemic stroke differ in type 2 diabetes. Am J Physiol Heart Circ Physiol 2013; 304:H806-15. [PMID: 23335797 DOI: 10.1152/ajpheart.00720.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hemorrhagic transformation is an important complication of acute ischemic stroke, particularly in diabetic patients receiving thrombolytic treatment with tissue plasminogen activator, the only approved drug for the treatment of acute ischemic stroke. The objective of the present study was to determine the effects of acute manipulation of potential targets for vascular protection [i.e., NF-κB, peroxynitrite, and matrix metalloproteinases (MMPs)] on vascular injury and functional outcome in a diabetic model of cerebral ischemia. Ischemia was induced by middle cerebral artery occlusion in control and type 2 diabetic Goto-Kakizaki rats. Treatment groups received a single dose of the peroxynitrite decomposition catalyst 5,10,15,20-tetrakis(4-sulfonatophenyl)prophyrinato iron (III), the nonspecific NF-κB inhibitor curcumin, or the broad-spectrum MMP inhibitor minocycline at reperfusion. Poststroke infarct volume, edema, hemorrhage, neurological deficits, and MMP-9 activity were evaluated. All acute treatments reduced MMP-9 and hemorrhagic transformation in diabetic groups. In addition, acute curcumin and minocycline therapy reduced edema in these animals. Improved neurological function was observed in varying degrees with treatment, as indicated by beam-walk performance, modified Bederson scores, and grip strength; however, infarct size was similar to untreated diabetic animals. In control animals, all treatments reduced MMP-9 activity, yet bleeding was not improved. Neuroprotection was only conferred by curcumin and minocycline. Uncovering the underlying mechanisms contributing to the success of acute therapy in diabetes will advance tailored stroke therapies.
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Affiliation(s)
- Aisha I Kelly-Cobbs
- Department of Physiology, Georgia Regents University Augusta, Augusta, GA 30912, USA
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