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Prasad S, Sajja RK, Kaisar MA, Cucullo L. Hyperglycemia exacerbates antiretroviral drug combination induced blood-brain barrier endothelial toxicity. Neurotoxicology 2016; 56:1-6. [PMID: 27345270 DOI: 10.1016/j.neuro.2016.06.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/09/2016] [Accepted: 06/22/2016] [Indexed: 12/24/2022]
Abstract
In this study, we sought to investigate how concomitant hyperglycemia influences the impact of combination antiretroviral therapy on blood-brain barrier (BBB) endothelial function. Immortalized human brain microvascular endothelial cell line (hCMEC/D3) was exposed to azidothymidine (AZT; a nucleoside reverse transcriptase inhibitor) and/or indinavir (IND; protease inhibitor) in normal glycemic (5.5mM) or hyperglycemic (HG; 25mM) media containing D-glucose for 24-72h. Cellular reactive oxygen species (ROS) and mitochondria-specific superoxide levels were assayed in addition to membrane potential to determine the extent of mitochondrial dysfunction. Nrf2 expression was analyzed by immunofluorescence. Our results indicated a significant increase in BBB endothelial toxicity (decreased ATP) by HG and AZT+IND with progression of time (24-72h). Concurrent HG and antiviral drug combination synergistically elevated BBB endothelial ROS induced by either condition alone. Further, HG and AZT+IND mutually interact to elicit a pronounced increase in mitochondrial superoxide levels post 24h (vs. either condition alone or controls). In addition, HG and AZT+IND complemented each other to induce potential loss of mitochondrial membrane potential. While HG or AZT+IND alone for 24h increased Nrf2 nuclear distribution, co-exposure conditions induced a potential loss of Nrf2 expression/nuclear translocation in BBB endothelium. In summary, our data strongly suggest that antiretroviral drug combination potentially interacts with concomitant HG and triggers exacerbated mitochondrial dysfunction and BBB endothelial toxicity, possibly through dysregulation of Nrf2 signaling. Thus, this study warrants the critical need for safety evaluation and monitoring of neurovascular complications of HAART regimens in HIV-infected diabetic patient cohort.
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Affiliation(s)
- Shikha Prasad
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX 79106, USA
| | - Ravi K Sajja
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX 79106, USA
| | - Mohammad A Kaisar
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX 79106, USA
| | - Luca Cucullo
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, 1300 S. Coulter Street, Amarillo, TX 79106, USA.
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52
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Pugazhenthi S, Qin L, Reddy PH. Common neurodegenerative pathways in obesity, diabetes, and Alzheimer's disease. Biochim Biophys Acta Mol Basis Dis 2016; 1863:1037-1045. [PMID: 27156888 DOI: 10.1016/j.bbadis.2016.04.017] [Citation(s) in RCA: 409] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 04/28/2016] [Accepted: 04/29/2016] [Indexed: 12/16/2022]
Abstract
Cognitive decline in chronic diabetic patients is a less investigated topic. Diabetes and obesity are among the modifiable risk factors for Alzheimer's disease (AD), the most common form of dementia. Studies have identified several overlapping neurodegenerative mechanisms, including oxidative stress, mitochondrial dysfunction, and inflammation that are observed in these disorders. Advanced glycation end products generated by chronic hyperglycemia and their receptor RAGE provide critical links between diabetes and AD. Peripheral inflammation observed in obesity leads to insulin resistance and type 2 diabetes. Although the brain is an immune-privileged organ, cross-talks between peripheral and central inflammation have been reported. Damage to the blood brain barrier (BBB) as seen with aging can lead to infiltration of immune cells into the brain, leading to the exacerbation of central inflammation. Neuroinflammation, which has emerged as an important cause of cognitive dysfunction, could provide a central mechanism for aging-associated ailments. To further add to these injuries, adult neurogenesis that provides neuronal plasticity is also impaired in the diabetic brain. This review discusses these molecular mechanisms that link obesity, diabetes and AD. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.
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Affiliation(s)
- Subbiah Pugazhenthi
- Section of Endocrinology, Veterans Affairs Medical Center, Denver, CO, USA; Department of Medicine, University of Colorado - Denver, Aurora, CO, USA.
| | - Limei Qin
- Section of Endocrinology, Veterans Affairs Medical Center, Denver, CO, USA
| | - P Hemachandra Reddy
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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53
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May JM. Ascorbic acid repletion: A possible therapy for diabetic macular edema? Free Radic Biol Med 2016; 94:47-54. [PMID: 26898503 PMCID: PMC4844774 DOI: 10.1016/j.freeradbiomed.2016.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/10/2016] [Accepted: 02/16/2016] [Indexed: 02/07/2023]
Abstract
Macular edema poses a significant risk for visual loss in persons with diabetic retinopathy. It occurs when plasma constituents and fluid leak out of damaged retinal microvasculature in the area of the macula, causing loss of central vision. Apoptotic loss of pericytes surrounding capillaries is perhaps the earliest feature of diabetic vascular damage in the macula, which is also associated with dysfunction of the endothelium and loss of the otherwise very tight endothelial permeability barrier. Increased oxidative stress is a key feature of damage to both cell types, mediated by excess superoxide from glucose-induced increases in mitochondrial metabolism, as well as by activation of the receptor for advanced glycation end products (RAGE). The latter in turn activates multiple pathways, some of which lead to increased oxidative stress, such as those involving NF-ĸB, NADPH oxidase, and endothelial nitric oxide synthase. Such cellular oxidative stress is associated with low cellular and plasma ascorbic acid levels in many subjects with diabetes in poor glycemic control. Whether repletion of low ascorbate in retinal endothelium and pericytes might help to prevent diabetic macular edema is unknown. However, cell culture studies show that the vitamin prevents high-glucose and RAGE-induced apoptosis in both cell types, that it preserves nitric oxide generated by endothelial cells, and that it tightens the leaky endothelial permeability barrier. Although these findings need to be confirmed in pre-clinical animal studies, it is worth considering clinical trials to determine whether adequate ascorbate repletion is possible and whether it might help to delay or even reverse early diabetic macular edema.
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Affiliation(s)
- James M May
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, United States.
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54
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Abdullah Z, Bayraktutan U. Suppression of PKC-α attenuates TNF-α-evoked cerebral barrier breakdown via regulations of MMP-2 and plasminogen-plasmin system. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1354-66. [PMID: 27094771 DOI: 10.1016/j.bbadis.2016.03.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/08/2016] [Accepted: 03/30/2016] [Indexed: 10/21/2022]
Abstract
Ischaemic stroke, accompanied by neuroinflammation, impairs blood-brain barrier integrity through a complex mechanism involving both protein kinase C (PKC) and urokinase. Using an in vitro model of human blood-brain barrier (BBB) composed of brain microvascular endothelial cells (HBMEC) and astrocytes, this study assessed the putative roles of these elements in BBB damage evoked by enhanced availability of pro-inflammatory cytokine, TNF-α. Treatment of HBMEC with TNF-α significantly increased the mRNA and protein expressions of all plasminogen-plasmin system (PPS) components, namely tissue plasminogen activator, urokinase, urokinase plasminogen activator receptor and plasminogen activator inhibitor-1 and also the activities of urokinase, total PKC and extracellular MMP-2. Inhibition of urokinase by amiloride abated the effects of TNF-α on BBB integrity and MMP-2 activity without affecting that of total PKC. Conversely, pharmacological inhibition of conventional PKC isoforms dramatically suppressed TNF-α-induced overactivation of urokinase. Knockdown of PKC-α gene via specific siRNA in HBMEC suppressed the stimulatory effects of TNF-α on protein expression of all PPS components, MMP-2 activity, DNA fragmentation rates and pro-apoptotic caspase-3/7 activities. Establishment of co-cultures with BMEC transfected with PKC-α siRNA attenuated the disruptive effects of TNF-α on BBB integrity and function. This was partly due to elevations observed in expression of a tight junction protein, claudin-5 and partly to prevention of stress fibre formation. In conclusion, specific inhibition of PKC-α in cerebral conditions associated with exaggerated release of pro-inflammatory cytokines, notably TNF-α may be of considerable therapeutic value and help maintain endothelial cell viability, appropriate cytoskeletal structure and basement membrane.
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Affiliation(s)
- Zuraidah Abdullah
- Stroke, Division of Clinical Neuroscience, Clinical Sciences Building, School of Medicine, Hucknall Road, Nottingham NG5 1PB, UK
| | - Ulvi Bayraktutan
- Stroke, Division of Clinical Neuroscience, Clinical Sciences Building, School of Medicine, Hucknall Road, Nottingham NG5 1PB, UK.
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55
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Hind WH, England TJ, O'Sullivan SE. Cannabidiol protects an in vitro model of the blood-brain barrier from oxygen-glucose deprivation via PPARγ and 5-HT1A receptors. Br J Pharmacol 2016; 173:815-25. [PMID: 26497782 DOI: 10.1111/bph.13368] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 10/08/2015] [Accepted: 10/13/2015] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND AND PURPOSE In vivo and in vitro studies have demonstrated a protective effect of cannabidiol (CBD) in reducing infarct size in stroke models and against epithelial barrier damage in numerous disease models. We aimed to investigate whether CBD also affects blood-brain barrier (BBB) permeability following ischaemia. EXPERIMENTAL APPROACH Human brain microvascular endothelial cell (HBMEC) and human astrocyte co-cultures modelled the BBB. Ischaemia was modelled by oxygen-glucose deprivation (OGD) and permeability was measured by transepithelial electrical resistance. KEY RESULTS CBD (10 μM) prevented the increase in permeability caused by 4 h OGD. CBD was most effective when administered before the OGD, but protective effects were observed up to 2 h into reperfusion. This protective effect was inhibited by a PPARγ antagonist and partly reduced by a 5-HT1A receptor antagonist, but was unaffected by antagonists of cannabinoid CB1 or CB2 receptors, TRPV1 channels or adenosine A2A receptors. CBD also reduced cell damage, as measured by LDH release and by markers of cellular adhesion, such as the adhesion molecule VCAM-1. In HBMEC monocultures, CBD decreased VCAM-1 and increased VEGF levels, effects which were inhibited by PPARγ antagonism. CONCLUSIONS AND IMPLICATIONS These data suggest that preventing permeability changes at the BBB could represent an as yet unrecognized mechanism of CBD-induced neuroprotection in ischaemic stroke, a mechanism mediated by activation of PPARγ and 5-HT1A receptors.
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Affiliation(s)
- William H Hind
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Timothy J England
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
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56
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Hyperglycemia-Induced Oxidative-Nitrosative Stress Induces Inflammation and Neurodegeneration via Augmented Tuberous Sclerosis Complex-2 (TSC-2) Activation in Neuronal Cells. Mol Neurobiol 2016; 54:238-254. [PMID: 26738854 DOI: 10.1007/s12035-015-9667-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 12/17/2015] [Indexed: 10/22/2022]
Abstract
Diabetes is a systemic disease mainly characterized by chronic hyperglycemia and with extensive and long-lasting spiteful complications in central nervous systems (CNS). Astrocytes play an important role in the defense mechanism of CNS, with great ability of withstanding accumulation of toxic substances. Apart from functional disorders, hyperglycemia leads to slow progressive structural abnormalities in the CNS through oxidative stress pathways. However, the molecular mechanism by which neurons die under oxidative stress induced by high glucose (HG) remains largely unclear. Here, we report that HG-induced inflammation and neurodegeneration in brain tissues, brain astrocytes (C6), and pheochromocytoma (PC-12) cells are cultured in HG conditions. Our results show that the increases in phosphorylation of Akt and ERK1/2MAPK are associated with increased accumulations of reactive oxygen species (ROS) in neuronal cells, which simultaneously enhanced phosphorylations of tuberous sclerosis complex-2 (TSC-2) and mammalian target of rapamycin (mTOR) in the diabetic brain and in HG-exposed neuronal cells. Pharmacologic inhibition of Akt or ERK1/2 or siRNA-mediated gene silencing of TSC-2 suppressed the strong downregulation of TSC-2-mTOR activation. Findings of this study also demonstrate that HG resulted in phosphorylation of NF-κB, coinciding with the increased production of inflammatory mediators and activation of neurodegenerative markers. Pretreatment of cells with antioxidants, phosphoinositide3-kinase (PI3-K)/Akt, and ERK1/2 inhibitors significantly reduced HG-induced TSC-2 phosphorylation and restored NF-κB protein expression leading to decreased production of inflammatory mediators and neurodegenerative markers. These results illustrate that ROS functions as a key signaling component in the regulatory pathway induced by elevated glucose in neuronal cell activation leading to inflammation and neurodegeneration.
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57
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Rakkar K, Bayraktutan U. Increases in intracellular calcium perturb blood–brain barrier via protein kinase C-alpha and apoptosis. Biochim Biophys Acta Mol Basis Dis 2016; 1862:56-71. [DOI: 10.1016/j.bbadis.2015.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 10/14/2015] [Accepted: 10/20/2015] [Indexed: 12/11/2022]
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58
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Esin RG, Esin OR, Khairullin IK. [Discirculatory encephalopathy and small vessel disease]. Zh Nevrol Psikhiatr Im S S Korsakova 2016. [PMID: 28635746 DOI: 10.17116/jnevro201611681109-113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The report examines the practicability of the term 'discirculatory encephalopathy' used in the Russian Federation to designate the chronic cerebral ischemia of different origin. The authors discuss the state of small vessel disease which manifests itself through slowly progressive cerebral changes. On the basis of their own research results and literature review the authors conclude that a standardized extract of Ginkgo biloba EGb761 (tanakan) can be effectively used in patients with small vessel disease.
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Affiliation(s)
- R G Esin
- Kazan State Medical Academy, Kazan, Russia; Kazan Federal University, Kazan, Russia
| | - O R Esin
- Kazan Federal University, Kazan, Russia
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59
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Fan A, Wang Q, Yuan Y, Cheng J, Chen L, Guo X, Li Q, Chen B, Huang X, Huang Q. Liver X receptor-α and miR-130a-3p regulate expression of sphingosine 1-phosphate receptor 2 in human umbilical vein endothelial cells. Am J Physiol Cell Physiol 2015; 310:C216-26. [PMID: 26669941 DOI: 10.1152/ajpcell.00102.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 11/23/2015] [Indexed: 02/07/2023]
Abstract
Recent studies have shown that activation of liver X receptors (LXRs) attenuates the development of atherosclerosis, not only by regulating lipid metabolism but also by suppressing inflammatory signaling. Sphingosine 1-phosphate receptor 2 (S1PR2), an important inflammatory gene product, plays a role in the development of various inflammatory diseases. It was proposed that S1PR2 might be regulated by LXR-α. In the present study, the effect of LXR-α on tumor necrosis factor-α (TNF-α)-induced S1PR2 expression in human umbilical vein endothelial cells (HUVECs) was investigated and the underlying mechanism was explored. The results demonstrated that TNF-α led to an increase in S1PR2 expression and triggered a downregulation of LXR-α expression in HUVECs as well. Downregulation of LXR-α with specific small interfering RNA (siRNA) remarkably enhanced the primary as well as TNF-α-induced expression of S1PR2 in HUVECs. Activation of LXR-α by agonist GW3965 inhibited both primary and TNF-α-induced S1PR2 expression. GW3965 also attenuated S1PR2-induced endothelial barrier dysfunction. The data further showed that TNF-α induced a significant decrease in miR-130a-3p expression. Overexpression of miR-130a-3p with mimic product reduced S1PR2 protein expression, and inhibition of miR-130a-3p by specific inhibitor resulted in an increase in S1PR2 protein expression. Furthermore, activation of LXRs with agonist enhanced the expression of miR-130a-3p, and knockdown of LXR-α by siRNA suppressed miR-130a-3p expression. These results suggest that LXR-α might downregulate S1PR2 expression via miR-130a-3p in quiescent HUVECs. Stimulation of TNF-α attenuates the activity of LXR-α and results in enhanced S1PR2 expression.
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Affiliation(s)
- Aihui Fan
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China; Department of Physiology, Guangdong Medical College, Dongguan, People's Republic of China; and
| | - Qian Wang
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China
| | - Yongjun Yuan
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China
| | - Jilun Cheng
- Department of Pharmacology, Guangdong Medical College, Dongguan, People's Republic of China
| | - Lixian Chen
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China
| | - Xiaohua Guo
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China
| | - Qiang Li
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China
| | - Bo Chen
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China
| | - Xuliang Huang
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China;
| | - Qiaobing Huang
- Department of Pathophysiology, Key Lab for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, People's Republic of China
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60
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Abdullah Z, Rakkar K, Bath PMW, Bayraktutan U. Inhibition of TNF-α protects in vitro brain barrier from ischaemic damage. Mol Cell Neurosci 2015; 69:65-79. [PMID: 26546149 DOI: 10.1016/j.mcn.2015.11.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 09/11/2015] [Accepted: 11/02/2015] [Indexed: 12/11/2022] Open
Abstract
Cerebral ischaemia, associated with neuroinflammation and oxidative stress, is known to perturb blood-brain barrier (BBB) integrity and promote brain oedema formation. Using an in vitro model of human BBB composed of brain microvascular endothelial cells and astrocytes, this study examined whether suppression of TNF-α, a potent pro-inflammatory cytokine, might attenuate ischaemia-mediated cerebral barrier damage. Radical decreases in transendothelial electrical resistance and concomitant increases in paracellular flux across co-cultures exposed to increasing periods of oxygen-glucose deprivation alone (0.5-20 h) or followed by 20 h of reperfusion (OGD ± R) confirmed the deleterious effects of ischaemic injury on cerebral barrier integrity and function which concurred with reductions in tight junction protein (claudin-5 and occludin) expressions. OGD ± R elevated TNF-α secretion, NADPH oxidase activity, O2(-) production, actin stress fibre formation, MMP-2/9 activities and apoptosis in both endothelial cells and astrocytes. Increases in MMP-2 activity were confined to its extracellular isoform and treatments with OGD+R in astrocytes where MMP-9 could not be detected at all. Co-exposure of individual cell lines or co-cultures to an anti-TNF-α antibody dramatically diminished the extent of OGD ± R-evoked oxidative stress, morphological changes, apoptosis, MMP-2/9 activities while improving the barrier function through upregulation of tight junction protein expressions. In conclusion, vitiation of the exaggerated release of TNF-α may be an important therapeutic strategy in preserving cerebral integrity and function during and following a cerebral ischaemic attack.
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Affiliation(s)
- Zuraidah Abdullah
- Stroke, Division of Clinical Neuroscience, University of Nottingham, UK
| | - Kamini Rakkar
- Stroke, Division of Clinical Neuroscience, University of Nottingham, UK
| | - Philip M W Bath
- Stroke, Division of Clinical Neuroscience, University of Nottingham, UK
| | - Ulvi Bayraktutan
- Stroke, Division of Clinical Neuroscience, University of Nottingham, UK.
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61
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Zhang J, Yang GM, Zhu Y, Peng XY, Li T, Liu LM. Role of connexin 43 in vascular hyperpermeability and relationship to Rock1-MLC20 pathway in septic rats. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1323-32. [PMID: 26342084 DOI: 10.1152/ajplung.00016.2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 08/31/2015] [Indexed: 12/27/2022] Open
Abstract
Connexin (Cx)43 has been shown to participate in several cardiovascular diseases. Increased vascular permeability is a common and severe complication in sepsis or septic shock. Whether or not Cx43 takes part in the regulation of vascular permeability in severe sepsis is not known, and the underlying mechanism has not been described. With cecal ligation and puncture-induced sepsis in rats and lipopolysaccharide (LPS)-treated vascular endothelial cells (VECs) from pulmonary veins, the role of Cx43 in increased vascular permeability and its relationship to the RhoA/Rock1 pathway were studied. It was shown that vascular permeability in the lungs, kidneys, and mesentery in sepsis rats and LPS-stimulated monolayer pulmonary vein VECs was significantly increased and positively correlated with the increased expression of Cx43 and Rock1 in these organs and cultured pulmonary vein VECs. The connexin inhibitor carbenoxolone (10 mg/kg iv) and the Rock1 inhibitor Y-27632 (2 mg/kg iv) alleviated the vascular leakage of lung, mesentery, and kidney in sepsis rats. Overexpressed Cx43 increased the phosphorylation of 20-kDa myosin light chain (MLC20) and the expression of Rock1 and increased the vascular permeability and decreased the transendothelial electrical resistance of pulmonary vein VECs. Cx43 RNA interference decreased the phosphorylation of MLC20 and the expression of Rock1 and decreased LPS-stimulated hyperpermeability of cultured pulmonary vein VECs. The Rock1 inhibitor Y-27632 alleviated LPS- and overexpressed Cx43-induced hyperpermeability of monolayer pulmonary vein VECs. This report shows that Cx43 participates in the regulation of vascular permeability in sepsis and that the mechanism is related to the Rock1-MLC20 phosphorylation pathway.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Trauma, Burns, and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Guang-Ming Yang
- State Key Laboratory of Trauma, Burns, and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Yu Zhu
- State Key Laboratory of Trauma, Burns, and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Xiao-Yong Peng
- State Key Laboratory of Trauma, Burns, and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Tao Li
- State Key Laboratory of Trauma, Burns, and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
| | - Liang-Ming Liu
- State Key Laboratory of Trauma, Burns, and Combined Injury, Second Department of Research Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing, People's Republic of China
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62
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Retinoic acid ameliorates blood–brain barrier disruption following ischemic stroke in rats. Pharmacol Res 2015; 99:125-36. [DOI: 10.1016/j.phrs.2015.05.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 05/30/2015] [Accepted: 05/31/2015] [Indexed: 01/28/2023]
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63
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Hind WH, Tufarelli C, Neophytou M, Anderson SI, England TJ, O'Sullivan SE. Endocannabinoids modulate human blood-brain barrier permeability in vitro. Br J Pharmacol 2015; 172:3015-27. [PMID: 25651941 PMCID: PMC4459020 DOI: 10.1111/bph.13106] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 01/20/2015] [Accepted: 02/01/2015] [Indexed: 12/11/2022] Open
Abstract
Background and Purpose Endocannabinoids alter permeability at various epithelial barriers, and cannabinoid receptors and endocannabinoid levels are elevated by stroke, with potential neuroprotective effects. We therefore explored the role of endocannabinoids in modulating blood–brain barrier (BBB) permeability in normal conditions and in an ischaemia/reperfusion model. Experimental Approach Human brain microvascular endothelial cell and astrocyte co-cultures modelled the BBB. Ischaemia was modelled by oxygen-glucose deprivation (OGD) and permeability was measured by transepithelial electrical resistance. Endocannabinoids or endocannabinoid-like compounds were assessed for their ability to modulate baseline permeability or OGD-induced hyperpermeability. Target sites of action were investigated using receptor antagonists and subsequently identified with real-time PCR. Key Results Anandamide (10 μM) and oleoylethanolamide (OEA, 10 μM) decreased BBB permeability (i.e. increased resistance). This was mediated by cannabinoid CB2 receptors, transient receptor potential vanilloid 1 (TRPV1) channels, calcitonin gene-regulated peptide (CGRP) receptor (anandamide only) and PPARα (OEA only). Application of OEA, palmitoylethanolamide (both PPARα mediated) or virodhamine (all 10 μM) decreased the OGD-induced increase in permeability during reperfusion. 2-Arachidonoyl glycerol, noladin ether and oleamide did not affect BBB permeability in normal or OGD conditions. N-arachidonoyl-dopamine increased permeability through a cytotoxic mechanism. PPARα and γ, CB1 receptors, TRPV1 channels and CGRP receptors were expressed in both cell types, but mRNA for CB2 receptors was only present in astrocytes. Conclusion and Implication The endocannabinoids may play an important modulatory role in normal BBB physiology, and also afford protection to the BBB during ischaemic stroke, through a number of target sites.
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Affiliation(s)
- William H Hind
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Cristina Tufarelli
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Maria Neophytou
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Susan I Anderson
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
| | - Timothy J England
- School of Medicine, University of Nottingham, Royal Derby Hospital, Derby, UK
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64
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Primary Pontine Hemorrhage in the Acute Stage: Clinical Features and a Proposed New Simple Scoring System. J Stroke Cerebrovasc Dis 2015; 24:860-5. [DOI: 10.1016/j.jstrokecerebrovasdis.2014.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/23/2014] [Accepted: 12/03/2014] [Indexed: 01/04/2023] Open
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65
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Bath PM, Wardlaw JM. Pharmacological treatment and prevention of cerebral small vessel disease: a review of potential interventions. Int J Stroke 2015; 10:469-78. [PMID: 25727737 PMCID: PMC4832291 DOI: 10.1111/ijs.12466] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 01/06/2015] [Indexed: 12/21/2022]
Abstract
Small vessel disease encompasses lacunar stroke, white matter hyperintensities, lacunes and microbleeds. It causes a quarter of all ischemic strokes, is the commonest cause of vascular dementia, and the cause is incompletely understood. Vascular prophylaxis, as appropriate for large artery disease and cardioembolism, includes antithrombotics, and blood pressure and lipid lowering; however, these strategies may not be effective for small vessel disease, or are already used routinely so precluding further detailed study. Further, intensive antiplatelet therapy is known to be hazardous in small vessel disease through enhanced bleeding. Whether acetylcholinesterase inhibitors, which delay the progression of Alzheimer's dementia, are relevant in small vessel disease remains unclear. Potential prophylactic and treatment strategies might be those that target brain microvascular endothelium and the blood brain barrier, microvascular function and neuroinflammation. Potential interventions include endothelin antagonists, neurotrophins, nitric oxide donors and phosphodiesterase 5 inhibitors, peroxisome proliferator‐activated receptor‐gamma agonists, and prostacyclin mimics and phosphodiesterase 3 inhibitors. Several drugs that have relevant properties are licensed for other disorders, offering the possibility of drug repurposing. Others are in development. Since influencing multiple targets may be most effective, using multiple agents and/or those that have multiple effects may be preferable. We focus on potential small vessel disease mechanistic targets, summarize drugs that have relevant actions, and review data available from randomized trials on their actions and on the available evidence for their use in lacunar stroke.
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Affiliation(s)
- Philip M Bath
- Stroke Trials Unit, Division of Clinical Neuroscience, University of Nottingham, Nottingham, UK
| | - Joanna M Wardlaw
- Division of Neuroimaging Sciences, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
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Blood glucose levels during the initial 72h and 3-month functional outcomes in acute intracerebral hemorrhage: The SAMURAI–ICH study. J Neurol Sci 2015; 350:75-8. [DOI: 10.1016/j.jns.2015.02.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/05/2015] [Accepted: 02/09/2015] [Indexed: 11/20/2022]
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Urday S, Kimberly WT, Beslow LA, Vortmeyer AO, Selim MH, Rosand J, Simard JM, Sheth KN. Targeting secondary injury in intracerebral haemorrhage--perihaematomal oedema. Nat Rev Neurol 2015; 11:111-22. [PMID: 25623787 DOI: 10.1038/nrneurol.2014.264] [Citation(s) in RCA: 183] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Perihaematomal oedema (PHO) is an important pathophysiological marker of secondary injury in intracerebral haemorrhage (ICH). In this Review, we describe a novel method to conceptualize PHO formation within the framework of Starling's principle of movement of fluid across a capillary wall. We consider progression of PHO through three stages, characterized by ionic oedema (stage 1) and progressive vasogenic oedema (stages 2 and 3). In this context, possible modifiers of PHO volume and their value in identifying patients who would benefit from therapies that target secondary injury are discussed; the practicalities of using neuroimaging to measure PHO volume are also considered. We examine whether PHO can be used as a predictor of neurological outcome following ICH, and we provide an overview of emerging therapies. Our discussion emphasizes that PHO has clinical relevance both as a therapeutic target, owing to its augmentation of the mass effect of a haemorrhage, and as a surrogate marker for novel interventions that target secondary injury.
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Affiliation(s)
- Sebastian Urday
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - W Taylor Kimberly
- Department of Neurology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Lauren A Beslow
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Alexander O Vortmeyer
- Department of Pathology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Magdy H Selim
- Department of Neurology, Beth Israel Deaconess Medical Centre, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Jonathan Rosand
- Department of Neurology, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, MD 21201-1559, USA
| | - Kevin N Sheth
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
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Zheng Y, Hu Q, Manaenko A, Zhang Y, Peng Y, Xu L, Tang J, Tang J, Zhang JH. 17β-Estradiol attenuates hematoma expansion through estrogen receptor α/silent information regulator 1/nuclear factor-kappa b pathway in hyperglycemic intracerebral hemorrhage mice. Stroke 2014; 46:485-91. [PMID: 25523052 DOI: 10.1161/strokeaha.114.006372] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND PURPOSE 17β-estradiol (E2) has been reported to reduce bleeding and brain injury in experimental intracerebral hemorrhage (ICH) model. However, it is not clear if E2 can prevent early hematoma expansion (HE) induced by hyperglycemia in acute ICH. The aim of this study is to evaluate the effects of E2 on HE and its potential mechanisms in hyperglycemic ICH mice. METHODS Two hundred, 8-week-old male CD1 mice were used. ICH was performed by collagenase injection. 50% dextrose (8 mL/kg) was injected intraperitoneally 3 hours after ICH to induce acute HE (normal saline was used as control). The time course of HE was measured 6, 24, and 72 hours after ICH. Two dosages (100 and 300 μg/kg) of E2 were administrated 1 hour after ICH intraperitoneally. Neurobehavioral deficits, hemorrhage volume, blood glucose level, and blood-brain barrier disruption were measured. To study the mechanisms of E2, estrogen receptor α (ERα) inhibitor methyl-piperidino-pyrazole, silent information regulator 1 (Sirt1) siRNA was administered, respectively. Protein expression of ERα, Sirt1, and acetylated nuclear factor-kappa B, and activity of matrix metalloproteinases-9 were detected. RESULTS Hyperglycemia enhanced HE and deteriorated neurological deficits after ICH from 6 hours after ICH. E2 treatment prevented blood-brain barrier disruption and improved neurological deficits 24 and 72 hours after ICH. E2 reduced HE by activating its receptor ERα, decreasing the expression of Sirt1, deacelylation of nuclear factor-kappa B, and inhibiting the activity of matrix metalloproteinases-9. ERα inhibitor methyl-piperidino-pyrazole and Sirt1 siRNA removed these effects of E2. CONCLUSIONS E2 treatment prevented hyperglycemia-enhanced HE and improved neurological deficits in ICH mice mediated by ERα/Sirt1/nuclear factor-kappa B pathway. E2 may serve as an alternative treatment to decrease early HE after ICH.
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Affiliation(s)
- Yun Zheng
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng)
| | - Qin Hu
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng)
| | - Anatol Manaenko
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng)
| | - Yang Zhang
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng)
| | - Yan Peng
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng)
| | - Liang Xu
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng)
| | - Junjia Tang
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng)
| | - Jiping Tang
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng)
| | - John H Zhang
- From the Departments of Physiology and Pharmacology (Y. Zheng, Q.H., A.M., Y. Zhang, Y.P., L.X., Junjia Tang, Jiping Tang, J.H.Z.), and Neurosurgery (J.H.Z.), Loma Linda University School of Medicine, Loma Linda, CA; and Department of Physiology, Medical School of Yangtze University, Jingzhou, Hubei, China (Y. Zheng).
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Li Q, Chen B, Zeng C, Fan A, Yuan Y, Guo X, Huang X, Huang Q. Differential activation of receptors and signal pathways upon stimulation by different doses of sphingosine-1-phosphate in endothelial cells. Exp Physiol 2014; 100:95-107. [PMID: 25557733 DOI: 10.1113/expphysiol.2014.082149] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 10/21/2014] [Indexed: 01/08/2023]
Abstract
NEW FINDINGS What is the central question of this study? Why do different doses of sphingosine-1-phosphate (S1P) induce distinct biological effects in endothelial cells? What is the main finding and its importance? S1P at physiological concentrations preserved endothelial barrier function by binding to S1P receptor 1, then triggering Ca(2+) release from endoplasmic reticulum through phosphoinositide phospholipase C and inositol triphosphate, and consequently strengthening tight junction and F-actin assembly through Rac1 activation. Excessive S1P induced endothelial malfunction by activating S1P receptor 2 and RhoA/ROCK pathway, causing F-actin and tight junction disorganisation. Extracellular Ca(2+) influx was involved in this process. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid in plasma, and its plasma concentration can be adjusted through a complex metabolic process. The alterations in S1P levels and the activation of receptors collaboratively regulate distinct biological effects. This study was performed to investigate comparatively the effect of different concentrations of S1P on endothelial barrier function and to explore the roles of S1P receptors (S1PRs), Rho GTPases and calcium in S1P-induced endothelial responses. Endothelial barrier function was studied using transendothelial electric resistance and a resistance meter in human umbilical vein endothelial cells. Specific agonists or antagonists were applied to control the activation of S1P receptors and the release of calcium from different cellular compartments. The results indicated that at physiological concentrations, S1P preserved endothelial barrier function by binding with S1PR1. The activation of S1PR1 triggered the release of intracellular Ca(2+) from the endoplasmic reticulum through the PI-phospholipase C and inositol trisphosphate pathways. Consequently, the Rho GTPase Rac1 was activated, strengthening the assembly of tight junction proteins and F-actin. However, excessive S1P induced endothelial barrier dysfunction by activating S1PR2 followed by the RhoA/RhoA kinase pathway, causing the disorganization of F-actin and the disassembly of the tight junction protein ZO-1. An influx of extracellular Ca(2+) was involved in this process. These data suggest that physiological and excessive amounts of S1P induce different responses in human umbilical vein endothelial cells; the activation of the 1PR1-PLC-IP3 R-Ca(2+) -Rac1 pathway governs the low-dose S1P-enhanced endothelial barrier integrity, and the activation of S1PR2-calcium influx-RhoA/ROCK dominates the high-dose S1P-induced endothelial monolayer hyperpermeability response.
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Affiliation(s)
- Qiang Li
- Department of Pathophysiology, Key Laboratory for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, 510515, PR China
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Campos-Bedolla P, Walter FR, Veszelka S, Deli MA. Role of the Blood–Brain Barrier in the Nutrition of the Central Nervous System. Arch Med Res 2014; 45:610-38. [DOI: 10.1016/j.arcmed.2014.11.018] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 11/24/2014] [Indexed: 12/22/2022]
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Combination approaches to attenuate hemorrhagic transformation after tPA thrombolytic therapy in patients with poststroke hyperglycemia/diabetes. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 71:391-410. [PMID: 25307224 DOI: 10.1016/bs.apha.2014.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To date, tissue type plasminogen activator (tPA)-based thrombolytic stroke therapy is the only FDA-approved treatment for achieving vascular reperfusion and clinical benefit, but this agent is given to only about 5% of stroke patients in the USA. This may be related, in part, to the elevated risk of symptomatic intracranial hemorrhage, and consequently limited therapeutic time window. Clinical investigations demonstrate that poststroke hyperglycemia is one of the most important risk factors that cause intracerebral hemorrhage and worsen neurological outcomes. There is a knowledge gap in understanding the underlying molecular mechanisms, and lack of effective therapeutics targeting the severe complication. This short review summarizes clinical observations and experimental investigations in preclinical stroke models of the field. The data strongly suggest that interactions of multiple pathogenic factors including hyperglycemia-mediated vascular oxidative stress and inflammation, ischemic insult, and tPA neurovascular toxicity in concert contribute to the BBB damage-intracerebral hemorrhagic transformation process. Development of combination approaches targeting the multiple pathological cascades may help to attenuate the hemorrhagic complication.
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Elmorsy E, Elzalabany LM, Elsheikha HM, Smith PA. Adverse effects of antipsychotics on micro-vascular endothelial cells of the human blood-brain barrier. Brain Res 2014; 1583:255-68. [PMID: 25139421 DOI: 10.1016/j.brainres.2014.08.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 08/07/2014] [Indexed: 01/16/2023]
Abstract
Although the mechanisms of action of antipsychotics (APs) on neuronal function are well understood, very little is known about their effects on cells of the blood-brain barrier (BBB); one function of which is to limit the access of these amphiphilic compounds to the central nervous system. To address this question we have investigated the cytological and functional effects of four APs: chlorpromazine (CLP), haloperidol (HAL), risperidone (RIS) and clozapine (CLZ), at concentrations typical of high therapeutic dosage on a human brain microvascular endothelial cell (HBMEC) model of the BBB. At ~10 µM all four APs impaired the ability of HBMECs to reduce MTT which was followed by decreased Trypan blue exclusion and increased Lactate dehydrogenase release. These effects were associated with oxidative stress which was partly reversed by incubation in 10mM glutathione. At their EC50 concentrations for MTT reduction, all four APs disrupted cellular ultrastructure and morphology. HAL, CPZ and CLZ increased Caspase -3, -8 and -9 activity, chromatin condensation and fragmentation, data indicative of apoptosis. These events were associated with decreased transcytosis of Evans blue and increased transendothelial potential difference and electrical resistance of this BBB model. These findings suggest that at high therapeutic concentrations, CPZ and CLZ are likely to incur cytoxic effects and apoptosis of BBB endothelia with an impairment of barrier functionality. Such events may underlie the aetiology of neuroleptic associated cerebral oedema and neuroleptic malignant syndrome.
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Affiliation(s)
- Ekramy Elmorsy
- School of Life Science, University of Nottingham Medical School, Queens Medical Centre, Nottinghamshire NG7 2UH, UK; Departments of Forensic Medicine and Clinical Toxicology, Faculty of Medicine, Mansoura University, Egypt
| | - Laila M Elzalabany
- Departments of Forensic Medicine and Clinical Toxicology, Faculty of Medicine, Mansoura University, Egypt
| | - Hany M Elsheikha
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
| | - Paul A Smith
- School of Life Science, University of Nottingham Medical School, Queens Medical Centre, Nottinghamshire NG7 2UH, UK.
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NADPH oxidase mediates TNF-α-evoked in vitro brain barrier dysfunction: roles of apoptosis and time. Mol Cell Neurosci 2014; 61:72-84. [PMID: 24907586 DOI: 10.1016/j.mcn.2014.06.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 05/20/2014] [Accepted: 06/02/2014] [Indexed: 11/20/2022] Open
Abstract
The pro-inflammatory cytokine TNF-α severely perturbs the integrity of the blood-brain barrier (BBB). This study explored the specific roles of NADPH oxidase and associated downstream effectors by using human brain microvascular endothelial cells (HBMECs) and human astrocytes (HAs), the key components of BBB, alone or in co-cultures to mimic human BBB. Exposure to TNF-α (6h) impaired BBB integrity as evidenced by marked decreases in transendothelial electrical resistance and concurrent increases in paracellular flux which appeared to subside with time (24h). Increased barrier dysfunction concurred with increases in endothelial NADPH oxidase activity, O2(-) production, actin stress fibre formation, MMP-2/9 activities and concomitant decreases in antioxidant (CuZn-SOD and catalase) and tight junction (claudin-5 and occludin) protein expressions. Conversely, TNF-α did not affect astrocytic MMP activities and antioxidant enzyme expressions. Unlike BBB damage, rates of HBMEC and HA apoptosis increased by time. Suppression of NADPH oxidase by apocynin or diphenyleneiodonium prevented TNF-α-evoked morphological changes and apoptosis, attenuated endothelial MMP activity and helped retain usual tight junction protein expression and barrier function. In conclusion, HBMECs constitute the main source of oxidative stress and basement-membrane degrading endopeptidases in inflammatory conditions associated with excessive release of TNF-α where targeting NADPH oxidase may prove extremely beneficial in maintaining proper barrier activity through prevention of cytoskeletal and tight junction reorganisations.
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75
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Shao B, Bayraktutan U. Hyperglycaemia promotes human brain microvascular endothelial cell apoptosis via induction of protein kinase C-ßI and prooxidant enzyme NADPH oxidase. Redox Biol 2014; 2:694-701. [PMID: 24936444 PMCID: PMC4052534 DOI: 10.1016/j.redox.2014.05.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 05/21/2014] [Accepted: 05/23/2014] [Indexed: 01/13/2023] Open
Abstract
Blood-brain barrier disruption represents a key feature in hyperglycaemia-aggravated cerebral damage after an ischaemic stroke. Although the underlying mechanisms remain largely unknown, activation of protein kinase C (PKC) is thought to play a critical role. This study examined whether apoptosis of human brain microvascular endothelial cells (HBMEC) might contribute to hyperglycaemia-evoked barrier damage and assessed the specific role of PKC in this phenomenon. Treatments with hyperglycaemia (25 mM) or phorbol myristate acetate (PMA, a protein kinase C activator, 100 nM) significantly increased NADPH oxidase activity, O2 (•-) generation, proapoptotic protein Bax expression, TUNEL-positive staining and caspase-3/7 activities. Pharmacological inhibition of NADPH oxidase, PKC-a, PKC-ß or PKC-ßI via their specific inhibitors and neutralisation of O2 (•-) by a cell-permeable superoxide dismutase mimetic, MnTBAP normalised all the aforementioned increases induced by hyperglycaemia. Suppression of these PKC isoforms also negated the stimulatory effects of hyperglycaemia on the protein expression of NADPH oxidase membrane-bound components, Nox2 and p22-phox which determine the overall enzymatic activity. Silencing of PKC-ßI gene through use of specific siRNAs abolished the effects of both hyperglycaemia and PMA on endothelial cell NADPH oxidase activity, O2 (•-) production and apoptosis and consequently improved the integrity and function of an in vitro model of human cerebral barrier comprising HBMEC, astrocytes and pericytes. Hyperglycaemia-mediated apoptosis of HBMEC contributes to cerebral barrier dysfunction and is modulated by sequential activations of PKC-ßI and NADPH oxidase.
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Affiliation(s)
- Beili Shao
- Stroke, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, UK
| | - Ulvi Bayraktutan
- Stroke, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, UK
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Takeshita T, Nakagawa S, Tatsumi R, So G, Hayashi K, Tanaka K, Deli MA, Nagata I, Niwa M. Cilostazol attenuates ischemia–reperfusion-induced blood–brain barrier dysfunction enhanced by advanced glycation endproducts via transforming growth factor-β1 signaling. Mol Cell Neurosci 2014; 60:1-9. [DOI: 10.1016/j.mcn.2014.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/19/2013] [Accepted: 01/19/2014] [Indexed: 11/30/2022] Open
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Rakkar K, Srivastava K, Bayraktutan U. Attenuation of urokinase activity during experimental ischaemia protects the cerebral barrier from damage through regulation of matrix metalloproteinase-2 and NAD(P)H oxidase. Eur J Neurosci 2014; 39:2119-28. [PMID: 24649947 DOI: 10.1111/ejn.12552] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/06/2014] [Accepted: 02/08/2014] [Indexed: 01/22/2023]
Abstract
Ischaemic injury impairs the integrity of the blood-brain barrier (BBB). In this study, we investigated the molecular causes of this defect with regard to the putative correlations among NAD(P)H oxidase, plasminogen-plasmin system components, and matrix metalloproteinases. Hence, the activities of NAD(P)H oxidase, matrix metalloproteinase-2, urokinase-type plasminogen activator (uPA), and tissue-type plasminogen activator (tPA), and superoxide anion levels, were assessed in human brain microvascular endothelial cells (HBMECs) exposed to oxygen-glucose deprivation (OGD) alone or OGD followed by reperfusion (OGD + R). The integrity of an in vitro model of BBB comprising HBMECs and astrocytes was studied by measuring transendothelial electrical resistance and the paracellular flux of albumin. OGD with or without reperfusion (OGD ± R) radically perturbed barrier function while concurrently enhancing uPA, tPA and NAD(P)H oxidase activities and superoxide anion release in HBMECs. Pharmacological inactivation of NAD(P)H oxidase attenuated OGD ± R-mediated BBB damage through modulation of matrix metalloproteinase-2 and tPA, but not uPA activity. Overactivation of NAD(P)H oxidase in HBMECs via cDNA electroporation of its p22-phox subunit confirmed the involvement of tPA in oxidase-mediated BBB disruption. Interestingly, blockade of uPA or uPA receptor preserved normal BBB function by neutralizing both NAD(P)H oxidase and matrix metalloproteinase-2 activities. Hence, selective targeting of uPA after ischaemic strokes may protect cerebral barrier integrity and function by concomitantly attenuating basement membrane degradation and oxidative stress.
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Affiliation(s)
- Kamini Rakkar
- Stroke, Division of Clinical Neuroscience, University of Nottingham, Clinical Sciences Building, Hucknall Road, Nottingham, NG5 1PB, UK
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Gibson CL, Srivastava K, Sprigg N, Bath PMW, Bayraktutan U. Inhibition of Rho-kinase protects cerebral barrier from ischaemia-evoked injury through modulations of endothelial cell oxidative stress and tight junctions. J Neurochem 2014; 129:816-26. [PMID: 24528233 DOI: 10.1111/jnc.12681] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/20/2014] [Accepted: 02/07/2014] [Indexed: 12/22/2022]
Abstract
Ischaemic strokes evoke blood-brain barrier (BBB) disruption and oedema formation through a series of mechanisms involving Rho-kinase activation. Using an animal model of human focal cerebral ischaemia, this study assessed and confirmed the therapeutic potential of Rho-kinase inhibition during the acute phase of stroke by displaying significantly improved functional outcome and reduced cerebral lesion and oedema volumes in fasudil- versus vehicle-treated animals. Analyses of ipsilateral and contralateral brain samples obtained from mice treated with vehicle or fasudil at the onset of reperfusion plus 4 h post-ischaemia or 4 h post-ischaemia alone revealed these benefits to be independent of changes in the activity and expressions of oxidative stress- and tight junction-related parameters. However, closer scrutiny of the same parameters in brain microvascular endothelial cells subjected to oxygen-glucose deprivation ± reperfusion revealed marked increases in prooxidant NADPH oxidase enzyme activity, superoxide anion release and in expressions of antioxidant enzyme catalase and tight junction protein claudin-5. Cotreatment of cells with Y-27632 prevented all of these changes and protected in vitro barrier integrity and function. These findings suggest that inhibition of Rho-kinase after acute ischaemic attacks improves cerebral integrity and function through regulation of endothelial cell oxidative stress and reorganization of intercellular junctions. Inhibition of Rho-kinase (ROCK) activity in a mouse model of human ischaemic stroke significantly improved functional outcome while reducing cerebral lesion and oedema volumes compared to vehicle-treated counterparts. Studies conducted with brain microvascular endothelial cells exposed to OGD ± R in the presence of Y-27632 revealed restoration of intercellular junctions and suppression of prooxidant NADPH oxidase activity as important factors in ROCK inhibition-mediated BBB protection.
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Affiliation(s)
- Claire L Gibson
- School of Psychology, University of Leicester, Leicester, UK
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Wang L, Luo H, Chen X, Jiang Y, Huang Q. Functional characterization of S100A8 and S100A9 in altering monolayer permeability of human umbilical endothelial cells. PLoS One 2014; 9:e90472. [PMID: 24595267 PMCID: PMC3940892 DOI: 10.1371/journal.pone.0090472] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 02/03/2014] [Indexed: 12/22/2022] Open
Abstract
S100A8, S100A9 and S100A8/A9 complexes have been known as important endogenous damage-associated molecular pattern (DAMP) proteins. But the pathophysiological roles of S100A8, S100A9 and S100A8/A9 in cardiovascular diseases are incompletely explained. In this present study, the effects of homo S100A8, S100A9 and their hetero-complex S100A8/A9 on endothelial barrier function were tested respectively in cultured human umbilical venous endothelial cells (HUVECs). The involvement of TLR4 and RAGE were observed by using inhibitor of TLR4 and blocking antibody of RAGE. The clarification of different MAPK subtypes in S100A8/A9-induced endothelial response was implemented by using specific inhibitors. The calcium-dependency was detected in the absence of Ca2+ or in the presence of gradient-dose Ca2+. The results showed that S100A8, S100A9 and S100A8/A9 could induce F-actin and ZO-1 disorganization in HUVECs and evoked the increases of HUVEC monolayer permeability in a dose- and time-dependent manner. The effects of S100A8, S100A9 and S100A8/A9 on endothelial barrier function depended on the activation of p38 and ERK1/2 signal pathways through receptors TLR4 and RAGE. Most importantly, we revealed the preference of S100A8 on TLR4 and S100A9 on RAGE in HUVECs. The results also showed the calcium dependency in S100A8- and S100A9-evoked endothelial response, indicating that calcium dependency on formation of S100A8 or A9 dimmers might be the prerequisite for this endothelial functional alteration.
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Affiliation(s)
- Liqun Wang
- Key Lab for Shock and Microcirculation Research of Guangdong, Department of Pathophysiology, Southern Medical University, Guangzhou, P. R. China
| | - Haihua Luo
- Key Laboratory for Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou, P. R. China
| | - Xiaohuan Chen
- Key Laboratory for Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou, P. R. China
| | - Yong Jiang
- Key Laboratory for Functional Proteomics of Guangdong Province, Department of Pathophysiology, Southern Medical University, Guangzhou, P. R. China
- * E-mail: (YJ); (QH)
| | - Qiaobing Huang
- Key Lab for Shock and Microcirculation Research of Guangdong, Department of Pathophysiology, Southern Medical University, Guangzhou, P. R. China
- * E-mail: (YJ); (QH)
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80
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Prasad S, Sajja RK, Naik P, Cucullo L. Diabetes Mellitus and Blood-Brain Barrier Dysfunction: An Overview. ACTA ACUST UNITED AC 2014; 2:125. [PMID: 25632404 DOI: 10.4172/2329-6887.1000125] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A host of diabetes-related insults to the central nervous system (CNS) have been clearly documented in type-1 and -2 diabetic patients as well as experimental animal models. These host of neurological disorders encompass hemodynamic impairments (e.g., stroke), vascular dementia, cognitive deficits (mild to moderate), as well as a number of neurochemical, electrophysiological and behavioral alterations. The underlying causes of diabetes-induced CNS complications are multifactorial and are relatively little understood although it is now evident that blood-brain barrier (BBB) damage plays a significant role in diabetes-dependent CNS disorders. Changes in plasma glucose levels (hyper- or hypoglycemia) have been associated with altered BBB transport functions (e.g., glucose, insulin, choline, amino acids, etc.), integrity (tight junction disruption), and oxidative stress in the CNS microcapillaries. Last two implicating a potential causal role for upregulation and activation of the receptor for advanced glycation end products (RAGE). This type I membrane-protein also transports amyloid-beta (Aβ) from the blood into the brain across the BBB thus, establishing a link between type 2 diabetes mellitus (T2DM) and Alzheimer's disease (AD, also referred to as "type 3 diabetes"). Hyperglycemia has been associated with progression of cerebral ischemia and the consequent enhancement of secondary brain injury. Difficulty in detecting vascular impairments in the large, heterogeneous brain microvascular bed and dissecting out the impact of hyper- and hypoglycemia in vivo has led to controversial results especially with regard to the effects of diabetes on BBB. In this article, we review the major findings and current knowledge with regard to the impact of diabetes on BBB integrity and function as well as specific brain microvascular effects of hyper- and hypoglycemia.
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Affiliation(s)
- Shikha Prasad
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health, Texas, USA
| | - Ravi K Sajja
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health, Texas, USA
| | - Pooja Naik
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health, Texas, USA
| | - Luca Cucullo
- Department of Pharmaceutical Sciences, School of Pharmacy, Texas Tech University Health, Texas, USA ; Vascular Drug research Center, Texas Tech University Health Sciences Center, Amarillo, Texas, USA
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81
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Shao B, Bayraktutan U. Hyperglycaemia promotes cerebral barrier dysfunction through activation of protein kinase C-β. Diabetes Obes Metab 2013; 15:993-9. [PMID: 23617822 DOI: 10.1111/dom.12120] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 12/28/2012] [Accepted: 04/19/2013] [Indexed: 01/21/2023]
Abstract
AIM To examine whether protein kinase C (PKC) and associated downstream mechanisms are involved in hyperglycaemia (HG)-evoked blood-brain barrier (BBB) damage. METHODS The activities of total PKC (Peptag assay), NADPH oxidase (lucigenin assay) and matrix metalloproteinase-2 (MMP-2; gelatin zymography) were measured in human brain microvascular endothelial cells (HBMEC) exposed to normoglycaemia (5.5 mM) or HG (25 mM) using the specific assays indicated in parentheses. The integrity and function of the in vitro models of human BBB were assessed by measurements of transendothelial electrical resistance and paracellular flux of permeability markers, respectively. Occludin protein expression was studied by immunoblotting. RESULTS HG significantly compromised the BBB integrity and enhanced total PKC activity to which increases in PKC-β and PKC-βII isoforms contributed the most. Elevations in NADPH oxidase and MMP-2 activities and decreases in occludin levels contributed to barrier dysfunction. Selective inhibition of PKC-β isoform prevented the changes observed in occludin expression and the aforementioned enzyme activities and thus effectively preserved barrier integrity. Similarly, apocynin, a specific NADPH oxidase inhibitor, also effectively neutralized the effects of HG on barrier integrity, MMP-2 activity, occludin expression and PKC-β activity. CONCLUSION HG promotes cerebral-barrier dysfunction through activation of PKC-β and consequent stimulations of oxidative stress and tight junction dissolution.
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Affiliation(s)
- B Shao
- Division of Stroke Medicine, School of Clinical Sciences, The University of Nottingham, Nottingham, UK
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82
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Liu C, Wu J, Zou MH. Activation of AMP-activated protein kinase alleviates high-glucose-induced dysfunction of brain microvascular endothelial cell tight-junction dynamics. Free Radic Biol Med 2012; 53:1213-21. [PMID: 22796592 PMCID: PMC3437014 DOI: 10.1016/j.freeradbiomed.2012.07.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Revised: 05/10/2012] [Accepted: 07/03/2012] [Indexed: 11/28/2022]
Abstract
The blood-brain barrier, formed by specialized brain endothelial cells that are interconnected by tight junctions, strictly regulates paracellular permeability to maintain an optimal extracellular environment for brain homeostasis. Diabetes is known to compromise the blood-brain barrier, although the underlying mechanism remains unknown. The aim of this study was to elucidate the molecular mechanisms underlying disruption of the blood-brain barrier in diabetes and to determine whether activation of AMP-activated protein kinase prevents diabetes-induced blood-brain barrier dysfunction. Exposure of human brain microvascular endothelial cells to high glucose (25 mmol/L D-glucose), but not to high osmotic conditions (20 mmol/L L-glucose plus 5 mmol/L D-glucose), for 2h to 1 week significantly increased the permeability of the blood-brain barrier in parallel with lowered expression levels of zonula occludens-1, occludin, and claudin-5, three proteins that are essential to maintaining endothelial cell tight junctions. In addition, high glucose significantly increased the generation of superoxide anions. Adenoviral overexpression of superoxide dismutase or catalase significantly attenuated the high-glucose-induced reduction of endothelial cell tight-junction proteins. Furthermore, administration of apocynin reversed the effects of high glucose on endothelial cell tight-junction proteins. Finally, activation of AMP-activated protein kinase with 5-amino-4-imidazole carboxamide riboside or adenoviral overexpression of constitutively active AMP-activated protein kinase mutants abolished both the induction of NAD(P)H oxidase-derived superoxide anions and the tight-junction protein degradation induced by high glucose. We conclude that high glucose increases blood-brain barrier dysfunction in diabetes through induction of superoxide anions and that the activation of AMP-activated protein kinase protects the integrity of the blood-brain barrier by suppressing the induction of NAD(P)H oxidase-derived superoxide anions.
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Affiliation(s)
- Chao Liu
- Hubei Province Key Laboratory on Cardiovascular, Cerebrovascular, and Metabolic Disorders, Xianning University, Xianning, Hubei 437100, China
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83
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Feng W, Tauhid S, Goel S, Sidorov EV, Selim M. Hyperglycemia and outcome in intracerebral hemorrhage: from bedside to bench-more study is needed. Transl Stroke Res 2012; 3:113-8. [PMID: 24323866 DOI: 10.1007/s12975-012-0163-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 03/19/2012] [Accepted: 03/21/2012] [Indexed: 12/22/2022]
Abstract
Hyperglycemia on admission has been associated with poor outcome after intracerebral hemorrhage (ICH). However, the mechanistic links between hyperglycemia and poor outcome are not fully elucidated. We sought to determine the relationship between the serum glucose levels during the first 72 h after ICH, and evolution of hematoma and perihematomal edema (PHE), and functional outcome at 3 months and performed a retrospective review of prospectively collected data from 135 consecutive ICH patients. Patients were divided into two groups based on their mean glucose level-high (≥150 mg/dl) vs. controlled (<150 mg/dl). We used Chi-square test and multiple logistic regressions to assess the relationship between glucose level and outcome variables, including hematoma expansion (HE), PHE growth, and modified Rankin Scale (mRS) score at 3 months. The mean 72-h glucose level was 123 ± 16 for the controlled group and 190 ± 48 mg/dl for the high-glucose group. The corresponding rates of HE were 23.4 vs. 25.9 % (unadjusted p = 0.80; adjusted p = 0.08); PHE growth, 31.3 vs. 29.6 % (unadjusted p = 0.88; adjusted p = 0.39); and poor outcome at 3 months, defined as mRS score of ≥3, was 54 vs. 71 % (unadjusted p = 0.06; adjusted p = 0.89). On multivariate analyses, the ICH score emerged as the major predictor for poor outcome, but not glucose. In conclusion, we found a trend for an association between mean 72 h glucose levels and poor outcome at 3 months, but this effect attenuated after adjusting for the ICH score. High glucose was not associated with HE or PHE growth. More preclinical and clinical studies are needed to elucidate the role of hyperglycemia in ICH before embarking on large and costly clinical trials of tight glucose control in ICH patients.
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Affiliation(s)
- Wuwei Feng
- Department of Neuroscience, MUSC Stroke Center, Medical University of South Carolina, Charleston, SC, USA
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84
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Hyperglycemia and endothelial dysfunction in atherosclerosis: lessons from type 1 diabetes. Int J Vasc Med 2012; 2012:569654. [PMID: 22489274 PMCID: PMC3303762 DOI: 10.1155/2012/569654] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 10/27/2011] [Indexed: 12/18/2022] Open
Abstract
A clear relationship between diabetes and cardiovascular disease has been established for decades. Despite this, the mechanisms by which diabetes contributes to plaque formation remain in question. Some of this confusion derives from studies in type 2 diabetics where multiple components of metabolic syndrome show proatherosclerotic effects independent of underlying diabetes. However, the hyperglycemia that defines the diabetic condition independently affects atherogenesis in cell culture systems, animal models, and human patients. Endothelial cell biology plays a central role in atherosclerotic plaque formation regulating vessel permeability, inflammation, and thrombosis. The current paper highlights the mechanisms by which hyperglycemia affects endothelial cell biology to promote plaque formation.
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85
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Stonestreet BS, Sadowska GB, Hanumara RC, Petrache M, Petersson KH, Patlak CS. Comparative effects of glucose- and mannitol-induced osmolar stress on blood-brain barrier function in ovine fetuses and lambs. J Cereb Blood Flow Metab 2012; 32:115-26. [PMID: 21878946 PMCID: PMC3324288 DOI: 10.1038/jcbfm.2011.114] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We examined the effects of hyperglycemic hyperosmolality on blood-brain barrier (BBB) permeability during development. We hypothesized that the barrier becomes more resistant to hyperglycemic hyperosmolality during development, and the immature BBB is more resistant to glucose than to mannitol hyperosmolality. We quantified the BBB response to hyperosmolality with the blood-to-brain transfer constant (K(i)) in immature fetuses, premature, and newborn lambs. K(i) increased as a function of increases in osmolality. A segmented regression model described the relationship between K(i) and osmolality. At lower osmolalities, changes in K(i) were minimal but after a threshold, increases were linear. We examined responses of K(i) to hyperglycemic hyperosmolality by comparing the thresholds and slopes of the second regression segments. Lower thresholds and steeper slopes indicate greater vulnerability to hyperosmolality. Thresholds increased (P<0.05) during development in pons and superior colliculus. Thresholds were higher (P<0.05) during glucose than mannitol hyperosmolality in thalamus, superior colliculus, inferior colliculus and medulla of premature lambs, and in cerebrum and cerebellum of newborns. We conclude that BBB permeability increased as a function of changes in glucose osmolality, the barrier becomes more resistant to glucose hyperosmolality in two brain regions during development, and the barrier is more resistant to glucose than to mannitol hyperosmolality in some brain regions of premature and newborn lambs.
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Affiliation(s)
- Barbara S Stonestreet
- Department of Pediatrics, The Alpert Medical School of Brown University, Women and Infants Hospital of Rhode Island, Providence, Rhode Island 02905-240, USA.
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86
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Oxidative Stress and β-Amyloid Protein in Alzheimer’s Disease. Neuromolecular Med 2011; 13:223-50. [DOI: 10.1007/s12017-011-8155-9] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 08/26/2011] [Indexed: 12/21/2022]
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87
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Afanas'ev I. Signaling of reactive oxygen and nitrogen species in Diabetes mellitus. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2010; 3:361-73. [PMID: 21311214 PMCID: PMC3154046 DOI: 10.4161/oxim.3.6.14415] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/26/2010] [Accepted: 12/06/2010] [Indexed: 02/07/2023]
Abstract
Disorder of physiological signaling functions of reactive oxygen species (ROS) superoxide and hydrogen peroxide and reactive nitrogen species (RNS) nitric oxide and peroxynitrite is an important feature of diabetes mellitus type 1 and type 2. It is now known that hyperglycemic conditions of cells are associated with the enhanced levels of ROS mainly generated by mitochondria and NADPH oxidase. It has been established that ROS stimulate many enzymatic cascades under normal physiological conditions, but hyperglycemia causes ROS overproduction and the deregulation of ROS signaling pathways initiating the development of diabetes mellitus. On the other hand the deregulation of RNS signaling leads basically to a decrease in NO formation with subsequent damaging disorders. In the present work we will consider the pathological changes of ROS and RNS signaling in enzyme/gene regulated processes catalyzed by protein kinases C and B (Akt/B), phosphatidylinositol 3'-kinase (PI3-kinase), extracellular signal-regulated kinase 1/2 (ERK1/2), and some others. Furthermore we will discuss a particularly important role of several ROS-regulated genes and adapter proteins such as the p66shc, FOXO3a, and Sirt2. The effects of low and high ROS levels in diabetes will be also considered. Thus the regulation of damaging ROS levels in diabetes by antioxidants and free radical scavengers must be one of promising treatment of this disease, however, because of the inability of traditional antioxidative vitamin E and C to interact with superoxide and hydrogen peroxide, new free radical scavengers such as flavonoids, quinones and synthetic mimetics of superoxide dismutase (SOD) should be intensively studied.
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88
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Allen C, Srivastava K, Bayraktutan U. Small GTPase RhoA and Its Effector Rho Kinase Mediate Oxygen Glucose Deprivation-Evoked In Vitro Cerebral Barrier Dysfunction. Stroke 2010; 41:2056-63. [DOI: 10.1161/strokeaha.109.574939] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background and Purpose—
Enhanced vascular permeability attributable to disruption of blood–brain barrier results in the development of cerebral edema after stroke. Using an in vitro model of the brain barrier composed of human brain microvascular endothelial cells and human astrocytes, this study explored whether small GTPase RhoA and its effector protein Rho kinase were involved in permeability changes mediated by oxygen-glucose deprivation (OGD), key pathological phenomena during ischemic stroke.
Methods and Results—
OGD increased RhoA and Rho kinase protein expressions in human brain microvascular endothelial cells and human astrocytes while increasing or unaffecting that of endothelial nitric oxide synthase in respective cells. Reperfusion attenuated the expression and activity of RhoA and Rho kinase in both cell types compared to their counterparts exposed to equal periods of OGD alone while selectively increasing human brain microvascular endothelial cells endothelial nitric oxide synthase protein levels. OGD compromised the barrier integrity as confirmed by decreases in transendothelial electric resistance and concomitant increases in flux of permeability markers sodium fluorescein and Evan’s blue albumin across cocultures. Transfection of cells with constitutively active RhoA also increased flux and reduced transendothelial electric resistance, whereas inactivation of RhoA by anti-RhoA Ig electroporation exerted opposite effects. In vitro cerebral barrier dysfunction was accompanied by myosin light chain overphosphorylation and stress fiber formation. Reperfusion and treatments with a Rho kinase inhibitor Y-27632 significantly attenuated barrier breakdown without profoundly altering actin structure.
Conclusions—
Increased RhoA/Rho kinase/myosin light chain pathway activity coupled with changes in actin cytoskeleton account for OGD-induced endothelial barrier breakdown.
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Affiliation(s)
- Claire Allen
- From the Division of Stroke, University of Nottingham, Nottingham, UK
| | | | - Ulvi Bayraktutan
- From the Division of Stroke, University of Nottingham, Nottingham, UK
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89
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Granger DN, Rodrigues SF, Yildirim A, Senchenkova EY. Microvascular responses to cardiovascular risk factors. Microcirculation 2010; 17:192-205. [PMID: 20374483 DOI: 10.1111/j.1549-8719.2009.00015.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hypertension, hypercholesterolemia, diabetes, and obesity are among a growing list of conditions that have been designated as major risk factors for cardiovascular disease (CVD). While CVD risk factors are well known to enhance the development of atherosclerotic lesions in large arteries, there is also evidence that the structure and function of microscopic blood vessels can be profoundly altered by these conditions. The diverse responses of the microvasculature to CVD risk factors include oxidative stress, enhanced leukocyte- and platelet-endothelial cell adhesion, impaired endothelial barrier function, altered capillary proliferation, enhanced thrombosis, and vasomotor dysfunction. Emerging evidence indicates that a low-grade systemic inflammatory response that results from risk factor-induced cell activation and cell-cell interactions may underlie the phenotypic changes induced by risk factor exposure. A consequence of the altered microvascular phenotype and systemic inflammatory response is an enhanced vulnerability of tissues to the deleterious effects of secondary oxidative and inflammatory stresses, such as ischemia and reperfusion. Future efforts to develop therapies that prevent the harmful effects of risk factor-induced inflammation should focus on the microcirculation.
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Affiliation(s)
- D Neil Granger
- Department of Molecular & Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130-3932, USA.
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90
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Current literature in diabetes. Diabetes Metab Res Rev 2009; 25:i-x. [PMID: 19790194 DOI: 10.1002/dmrr.1037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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