1
|
Protective Effects of Fucoxanthin on Hydrogen Peroxide-Induced Calcification of Heart Valve Interstitial Cells. Mar Drugs 2021; 19:md19060307. [PMID: 34073219 PMCID: PMC8227531 DOI: 10.3390/md19060307] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/20/2021] [Accepted: 05/22/2021] [Indexed: 12/24/2022] Open
Abstract
Cardiovascular diseases such as atherosclerosis and aortic valve sclerosis involve inflammatory reactions triggered by various stimuli, causing increased oxidative stress. This increased oxidative stress causes damage to the heart cells, with subsequent cell apoptosis or calcification. Currently, heart valve damage or heart valve diseases are treated by drugs or surgery. Natural antioxidant products are being investigated in related research, such as fucoxanthin (Fx), which is a marine carotenoid extracted from seaweed, with strong antioxidant, anti-inflammatory, and anti-tumor properties. This study aimed to explore the protective effect of Fx on heart valves under high oxidative stress, as well as the underlying mechanism of action. Rat heart valve interstitial cells under H2O2-induced oxidative stress were treated with Fx. Fx improved cell survival and reduced oxidative stress-induced DNA damage, which was assessed by cell viability analysis and staining with propidium iodide. Alizarin Red-S analysis indicated that Fx has a protective effect against calcification. Furthermore, Western blotting revealed that Fx abrogates oxidative stress-induced apoptosis via reducing the expression of apoptosis-related proteins as well as modulate Akt/ERK-related protein expression. Notably, in vivo experiments using 26 dogs treated with 60 mg/kg of Fx in combination with medical treatment for 0.5 to 2 years showed significant recovery in their echocardiographic parameters. Collectively, these in vitro and in vivo results highlight the potential of Fx to protect heart valve cells from high oxidative stress-induced damage.
Collapse
|
2
|
Liu J, Ji XX, Fu Y, Zhang WC, Ji HF, Liu JW, Cheng XS, Dong YF. Early Passive Leg Movement Prevents Against the Development of Heart Failure With Preserved Ejection Fraction in Rats. Front Cardiovasc Med 2021; 8:655009. [PMID: 33969019 PMCID: PMC8096912 DOI: 10.3389/fcvm.2021.655009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/26/2021] [Indexed: 01/19/2023] Open
Abstract
Exercising was reported by several studies to bring great benefits to heart failure with preserved ejection fraction (HFpEF), which reduced the hospitalization and the mortality of heart failure. However, the underlying mechanism of exercising on HFpEF remains unclear. In the present study, we designed and constructed a device that can perform early passive leg movement (ePLM) in rats and further observed whether treatment of ePLM exerts protective effects on HFpEF of rats. Rats were fed with high salt feed to establish an animal model of pre-clinical diastolic dysfunction (PDD), which would eventually develop into HFpEF, and then treated rats with ePLM. We conducted several experiments to evaluate the conditions of heart and blood vessel. The results show that diastolic functions of heart and blood vessel in rats were significantly improved by treatment of ePLM. We also found that pathological injuries of heart and blood vessel were ameliorated after treatment of ePLM. Moreover, treatment of ePLM decreased the protein levels of Collagen type I, Collagen type III, MMP2, and MMP9 in heart and blood vessel, indicating that cardiac and vascular fibrosis were reduced apparently by treatment of ePLM. Further investigation suggested that treatment of ePLM probably inhibit the activation of TGF-β1/Smad3 signaling pathway as well as promote the activation of Akt/eNOS signaling pathway in high salt diet induced HFpEF. In conclusion, treatment of ePLM alleviated high salt diet induced HFpEF by inhibiting fibrosis via suppressing TGF-β1/Smad3 signaling pathway as well as activating Akt/eNOS signaling pathway, implicating treatment of ePLM as a promising novel non-pharmacological approach for HFpEF.
Collapse
Affiliation(s)
- Jian Liu
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China.,The First People's Hospital of Yongkang, Yongkang, China
| | - Xi-Xin Ji
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Yang Fu
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Wen-Chao Zhang
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Hui-Fang Ji
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Jian-Wei Liu
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Xiao-Shu Cheng
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| | - Yi-Fei Dong
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Nanchang University, Nanchang, China
| |
Collapse
|
3
|
Zhang R, Wang L, Zhao QH, Jiang R, Gong SG, Jiang X, Xu XQ, He YY, Li Y, Jing ZC. Alteration of Extracellular Superoxide Dismutase in Idiopathic Pulmonary Arterial Hypertension. Front Med (Lausanne) 2020; 7:509. [PMID: 33282881 PMCID: PMC7705200 DOI: 10.3389/fmed.2020.00509] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/23/2020] [Indexed: 01/07/2023] Open
Abstract
Background: Superoxide dismutases (SODs) are an important family of antioxidant enzymes that modulate reactive oxygen species levels. It is largely unknown which SOD isoform(s) change in vivo in idiopathic pulmonary arterial hypertension (IPAH) patients. Methods: A total of 133 consecutive adult IPAH patients who underwent bone morphogenetic protein receptor type 2 (BMPR2) genetic counseling were enrolled in this prospective study. The plasma activities of three subtypes of SOD [copper–zinc (Cu/Zn-SOD), manganese (Mn-SOD), and extracellular SOD (Ec-SOD)] were examined. Results: The activities of SODs were significantly lower in IPAH patients than in healthy subjects. However, only Ec-SOD activity in BMPR2 mutation patients was significantly decreased compared to those in patients without a mutation. The reduced Ec-SOD activity was markedly associated with mean pulmonary arterial pressure, pulmonary vascular resistance (PVR), and 6-min walking distance (6MWD). The reduction of Mn-SOD activity was only associated with 6MWD. There was no association between Cu/Zn-SOD and hemodynamics. Patients with a lower Ec-SOD level had a worse survival compared to those with a higher baseline. The reduced Ec-SOD activity and the raised PVR increased the mortality risk. Conclusions: Ec-SOD was correlated with BMPR2 mutation, hemodynamic dysfunction, and poor outcomes. Circulating Ec-SOD could be a potentially vital antioxidant enzyme in the pathogenesis of IPAH.
Collapse
Affiliation(s)
- Rui Zhang
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lan Wang
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qin-Hua Zhao
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Rong Jiang
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Su-Gang Gong
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xin Jiang
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xi-Qi Xu
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yang-Yang He
- Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yuan Li
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhi-Cheng Jing
- Department of Cardio-Pulmonary Circulation, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| |
Collapse
|
4
|
Li J, Teng X, Jin S, Dong J, Guo Q, Tian D, Wu Y. Hydrogen sulfide improves endothelial dysfunction by inhibiting the vicious cycle of NLRP3 inflammasome and oxidative stress in spontaneously hypertensive rats. J Hypertens 2020; 37:1633-1643. [PMID: 31058793 DOI: 10.1097/hjh.0000000000002101] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To elucidate whether by inhibiting inflammasome and oxidative stress, hydrogen sulfide (H2S) can ameliorate endothelial dysfunction with hypertension. METHODS Spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) were injected with 100 μmol/l sodium hydrosulfide (NaHS) intraperitoneally daily for 16 weeks. SBP and plasma malondialdehyde (MDA) and interleukin 1β (IL-1β) levels were measured. Renal vascular function was used to determine endothelial-dependent contraction (EDC) and endothelial-dependent relaxation (EDR). Protein levels of NOX1, p67, Nrf2, SOD1, CAT, NLRP3, caspase-1 and IL-1β were detected by western blot analysis. Human umbilical vein endothelial cells (HUVECs) were used to confirm the protective role of H2S against angiotensin II (Ang II)-induced cell injury. RESULTS Exogenous NaHS administration significantly reduced SBP and ameliorated damaged EDC and EDR. H2S reduced the activation of NLRP3 inflammasome and oxidative stress in SHR. The endothelial protective and antioxidant effect of H2S was abolished by lipopolysaccharide, an inducer of NLRP3 inflammasome. In HUVECs, H2S significantly ameliorated Ang II-induced cellular impairment, NLRP3 inflammasome activity and reactive oxygen species generation. After knocking down Nrf2, the protective effect of H2S was abolished. CONCLUSION H2S could inhibit the vicious cycle of oxidative stress and inflammation in hypertension, and then improve endothelial function and ameliorated hypertension. Our results help to reveal the crucial role of H2S in regulating endothelial function, which might be a new tool for treating hypertension.
Collapse
Affiliation(s)
- Jiabao Li
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University
| | - Xu Teng
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University.,Hebei Key Lab of Laboratory Animal Science, Hebei Medical University, Shijiazhuang, China
| | - Sheng Jin
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University
| | - Jinghui Dong
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University
| | - Qi Guo
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University
| | - Danyang Tian
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University
| | - Yuming Wu
- Department of Physiology, Institute of Basic Medicine, Hebei Medical University.,Key Laboratory of Vascular Medicine of Hebei Province.,Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease
| |
Collapse
|
5
|
Rosenblum WI. Endothelium-dependent responses in the microcirculation observed in vivo. Acta Physiol (Oxf) 2018; 224:e13111. [PMID: 29873936 DOI: 10.1111/apha.13111] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/19/2018] [Accepted: 06/04/2018] [Indexed: 12/17/2022]
Abstract
Endothelium-dependent responses were first demonstrated 40 years ago in the aorta. Since then, extensive research has been conducted in vitro using conductance vessels and materials derived from them. However, the microcirculation controls blood flow to vital organs and has been the focus of in vivo studies of endothelium-dependent dilation beginning immediately after the first in vitro report. Initial in vivo studies employed a light/dye technique for selectively damaging the endothelium to unequivocally prove, in vivo, the existence of endothelium-dependent dilation and in the microvasculature. Endothelium-dependent constriction was similarly proven. Endothelium-dependent agonists include acetylcholine (ACh), bradykinin, arachidonic acid, calcium ionophore A-23187, calcitonin gene-related peptide (CGRP), serotonin, histamine and endothelin-1. Normal and disease states have been studied. Endothelial nitric oxide synthase, cyclooxygenase and cytochrome P450 have been shown to generate the mediators of the responses. Some of the key enzyme systems generate reactive oxygen species (ROS) like superoxide which may prevent EDR. However, one ROS, namely H2 O2 , is one of a number of hyperpolarizing factors that cause dilation initiated by endothelium. Depending upon microvascular bed, a single agonist may use different pathways to elicit an endothelium-dependent response. Interpretation of studies using inhibitors of eNOS is complicated by the fact that these inhibitors may also inhibit ATP-sensitive potassium channels. Other in vivo observations of brain arterioles failed to establish nitric oxide as the mediator of responses elicited by CGRP or by ACh and suggest that a nitrosothiol may be a better fit for the latter.
Collapse
Affiliation(s)
- W. I. Rosenblum
- Department of Pathology; Icahn School of Medicine at Mt Sinai NYC; New York NY USA
| |
Collapse
|
6
|
Wray DW, Amann M, Richardson RS. Peripheral vascular function, oxygen delivery and utilization: the impact of oxidative stress in aging and heart failure with reduced ejection fraction. Heart Fail Rev 2018; 22:149-166. [PMID: 27392715 DOI: 10.1007/s10741-016-9573-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The aging process appears to be a precursor to many age-related diseases, perhaps the most impactful of which is cardiovascular disease (CVD). Heart disease, a manifestation of CVD, is the leading cause of death in the USA, and heart failure (HF), a syndrome that develops as a consequence of heart disease, now affects almost six million American. Importantly, as this is an age-related disease, this number is likely to grow along with the ever-increasing elderly population. Hallmarks of the aging process and HF patients with a reduced ejection fraction (HFrEF) include exercise intolerance, premature fatigue, and limited oxygen delivery and utilization, perhaps as a consequence of diminished peripheral vascular function. Free radicals and oxidative stress have been implicated in this peripheral vascular dysfunction, as a redox imbalance may directly impact the function of the vascular endothelium. This review aims to bring together studies that have examined the impact of oxidative stress on peripheral vascular function and oxygen delivery and utilization with both healthy aging and HFrEF.
Collapse
Affiliation(s)
- D Walter Wray
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Bldg 2, Rm 1D25, 500 Foothill Drive, Salt Lake City, UT, 84148, USA
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Markus Amann
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Bldg 2, Rm 1D25, 500 Foothill Drive, Salt Lake City, UT, 84148, USA
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.
- Geriatric Research, Education, and Clinical Center, VA Medical Center, Bldg 2, Rm 1D25, 500 Foothill Drive, Salt Lake City, UT, 84148, USA.
- Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA.
| |
Collapse
|
7
|
Cellular and Oxidative Mechanisms Associated with Interleukin-6 Signaling in the Vasculature. Int J Mol Sci 2017; 18:ijms18122563. [PMID: 29186034 PMCID: PMC5751166 DOI: 10.3390/ijms18122563] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 11/17/2017] [Accepted: 11/19/2017] [Indexed: 02/07/2023] Open
Abstract
Reactive oxygen species, particularly superoxide, promote endothelial dysfunction and alterations in vascular structure. It is increasingly recognized that inflammatory cytokines, such as interleukin-6 (IL-6), contribute to endothelial dysfunction and vascular hypertrophy and fibrosis. IL-6 is increased in a number of cardiovascular diseases, including hypertension. IL-6 is also associated with a higher incidence of future cardiovascular events and all-cause mortality. Both immune and vascular cells produce IL-6 in response to a number of stimuli, such as angiotensin II. The vasculature is responsive to IL-6 produced from vascular and non-vascular sources via classical IL-6 signaling involving a membrane-bound IL-6 receptor (IL-6R) and membrane-bound gp130 via Jak/STAT as well as SHP2-dependent signaling pathways. IL-6 signaling is unique because it can also occur via a soluble IL-6 receptor (sIL-6R) which allows for IL-6 signaling in tissues that do not normally express IL-6R through a process referred to as IL-6 trans-signaling. IL-6 signaling mediates a vast array of effects in the vascular wall, including endothelial activation, vascular permeability, immune cell recruitment, endothelial dysfunction, as well as vascular hypertrophy and fibrosis. Many of the effects of IL-6 on vascular function and structure are representative of loss or reductions in nitric oxide (NO) bioavailability. IL-6 has direct effects on endothelial nitric oxide synthase activity and expression as well as increasing vascular superoxide, which rapidly inactivates NO thereby limiting NO bioavailability. The goal of this review is to highlight both the cellular and oxidative mechanisms associated with IL-6-signaling in the vascular wall in general, in hypertension, and in response to angiotensin II.
Collapse
|
8
|
Matin N, Fisher C, Jackson WF, Diaz-Otero JM, Dorrance AM. Carotid artery stenosis in hypertensive rats impairs dilatory pathways in parenchymal arterioles. Am J Physiol Heart Circ Physiol 2017; 314:H122-H130. [PMID: 28842441 DOI: 10.1152/ajpheart.00638.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hypertension is a leading risk factor for vascular cognitive impairment and is strongly associated with carotid artery stenosis. In normotensive rats, chronic cerebral hypoperfusion induced by bilateral common carotid artery stenosis (BCAS) leads to cognitive impairment that is associated with impaired endothelium-dependent dilation in parenchymal arterioles (PAs). The aim of this study was to assess the effects of BCAS on PA function and structure in stroke-prone spontaneously hypertensive rats, a model of human essential hypertension. Understanding the effects of hypoperfusion on PAs in a hypertensive model could lead to the identification of therapeutic targets for cognitive decline in a model that reflects the at-risk population. We hypothesized that BCAS would impair endothelium-dependent dilation in PAs and induce artery remodeling compared with sham rats. PAs from BCAS rats had endothelial dysfunction, as assessed using pressure myography. Inhibition of nitric oxide and prostaglandin production had no effect on PA dilation in sham or BCAS rats. Surprisingly, inhibition of epoxyeicosatrienoic acid production increased dilation in PAs from BCAS rats but not from sham rats. Similar results were observed in the presence of inhibitors for all three dilatory pathways, suggesting that epoxygenase inhibition may have restored a nitric oxide/prostaglandin-independent dilatory pathway in PAs from BCAS rats. PAs from BCAS rats underwent remodeling with a reduced wall thickness. These data suggest that marked endothelial dysfunction in PAs from stroke-prone spontaneously hypertensive rats with BCAS may be associated with the development of vascular cognitive impairment. NEW & NOTEWORTHY The present study assessed the structure and function of parenchymal arterioles in a model of chronic cerebral hypoperfusion and hypertension, both of which are risk factors for cognitive impairment. We observed that impaired dilation and artery remodeling in parenchymal arterioles and abolished cerebrovascular reserve capacity may mediate cognitive deficits.
Collapse
Affiliation(s)
- Nusrat Matin
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - Courtney Fisher
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - Janice M Diaz-Otero
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| | - Anne M Dorrance
- Department of Pharmacology and Toxicology, Michigan State University , East Lansing, Michigan
| |
Collapse
|
9
|
De Silva TM, Faraci FM. Reactive Oxygen Species and the Regulation of Cerebral Vascular Tone. STUDIES ON ATHEROSCLEROSIS 2017. [DOI: 10.1007/978-1-4899-7693-2_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
10
|
Microvascular Dysfunction and Cognitive Impairment. Cell Mol Neurobiol 2016; 36:241-58. [PMID: 26988697 DOI: 10.1007/s10571-015-0308-1] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 11/19/2015] [Indexed: 12/18/2022]
Abstract
The impact of vascular risk factors on cognitive function has garnered much interest in recent years. The appropriate distribution of oxygen, glucose, and other nutrients by the cerebral vasculature is critical for proper cognitive performance. The cerebral microvasculature is a key site of vascular resistance and a preferential target for small vessel disease. While deleterious effects of vascular risk factors on microvascular function are known, the contribution of this dysfunction to cognitive deficits is less clear. In this review, we summarize current evidence for microvascular dysfunction in brain. We highlight effects of select vascular risk factors (hypertension, diabetes, and hyperhomocysteinemia) on the pial and parenchymal circulation. Lastly, we discuss potential links between microvascular disease and cognitive function, highlighting current gaps in our understanding.
Collapse
|
11
|
Springo Z, Tarantini S, Toth P, Tucsek Z, Koller A, Sonntag WE, Csiszar A, Ungvari Z. Aging Exacerbates Pressure-Induced Mitochondrial Oxidative Stress in Mouse Cerebral Arteries. J Gerontol A Biol Sci Med Sci 2015; 70:1355-9. [PMID: 25631392 PMCID: PMC4612385 DOI: 10.1093/gerona/glu244] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 12/08/2014] [Indexed: 12/21/2022] Open
Abstract
Epidemiological studies demonstrate that in addition to the increased prevalence of hypertension in old patients, the deleterious cerebrovascular effects of hypertension (including atherosclerosis, stroke, and vascular cognitive impairment) are also exacerbated in elderly individuals. The cellular mechanisms by which aging and hypertension interact to promote cerebrovascular pathologies are not well understood. To test the hypothesis that aging exacerbates high pressure-induced mitochondrial oxidative stress, we exposed isolated segments of the middle cerebral arteries of young (3 months) and aged (24 months) C57BL/6 mice to 60 or 140 mmHg intraluminal pressure and assessed changes in mitochondrial reactive oxygen species production using a mitochondria-targeted redox-sensitive fluorescent indicator dye (MitoSox) by confocal microscopy. Perinuclear MitoSox fluorescence was significantly stronger in high pressure-exposed middle cerebral arteries compared with middle cerebral arteries of the same animals exposed to 60 mmHg, indicating that high pressure increases mitochondrial reactive oxygen species production in the smooth muscle cells of cerebral arteries. Comparison of young and aged middle cerebral arteries showed that aging exacerbates high pressure-induced mitochondrial reactive oxygen species production in cerebral arteries. We propose that increased mechanosensitive mitochondrial oxidative stress may potentially exacerbate cerebrovascular injury and vascular inflammation in aging.
Collapse
Affiliation(s)
- Zsolt Springo
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center. Department of Pathophysiology and Gerontology, Medical School and Szentágothai Research Center, University of Pecs, Hungary
| | - Stefano Tarantini
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center
| | - Peter Toth
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center
| | - Zsuzsanna Tucsek
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center
| | - Akos Koller
- Department of Pathophysiology and Gerontology, Medical School and Szentágothai Research Center, University of Pecs, Hungary
| | - William E Sonntag
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center. The Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center
| | - Anna Csiszar
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center. Department of Pathophysiology and Gerontology, Medical School and Szentágothai Research Center, University of Pecs, Hungary. The Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center
| | - Zoltan Ungvari
- Reynolds Oklahoma Center on Aging, Donald W. Reynolds Department of Geriatric Medicine, University of Oklahoma Health Sciences Center. Department of Pathophysiology and Gerontology, Medical School and Szentágothai Research Center, University of Pecs, Hungary. The Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center.
| |
Collapse
|
12
|
Gudiño-Cabrera G, Ureña-Guerrero ME, Rivera-Cervantes MC, Feria-Velasco AI, Beas-Zárate C. Excitotoxicity triggered by neonatal monosodium glutamate treatment and blood-brain barrier function. Arch Med Res 2014; 45:653-9. [PMID: 25431840 DOI: 10.1016/j.arcmed.2014.11.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 11/13/2014] [Indexed: 12/21/2022]
Abstract
It is likely that monosodium glutamate (MSG) is the excitotoxin that has been most commonly employed to characterize the process of excitotoxicity and to improve understanding of the ways that this process is related to several pathological conditions of the central nervous system. Excitotoxicity triggered by neonatal MSG treatment produces a significant pathophysiological impact on adulthood, which could be due to modifications in the blood-brain barrier (BBB) permeability and vice versa. This mini-review analyzes this topic through brief descriptions about excitotoxicity, BBB structure and function, role of the BBB in the regulation of Glu extracellular levels, conditions that promote breakdown of the BBB, and modifications induced by neonatal MSG treatment that could alter the behavior of the BBB. In conclusion, additional studies to better characterize the effects of neonatal MSG treatment on excitatory amino acids transporters, ionic exchangers, and efflux transporters, as well as the role of the signaling pathways mediated by erythropoietin and vascular endothelial growth factor in the cellular elements of the BBB, should be performed to identify the mechanisms underlying the increase in neurovascular permeability associated with excitotoxicity observed in several diseases and studied using neonatal MSG treatment.
Collapse
Affiliation(s)
- Graciela Gudiño-Cabrera
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, México
| | - Monica E Ureña-Guerrero
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, México
| | - Martha C Rivera-Cervantes
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, México
| | - Alfredo I Feria-Velasco
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, México
| | - Carlos Beas-Zárate
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Zapopan, Jalisco, México; División de Neurociencias, CIBO, IMSS, Guadalajara, Jalisco, México.
| |
Collapse
|
13
|
Golub AS, Pittman RN. Bang-bang model for regulation of local blood flow. Microcirculation 2014; 20:455-83. [PMID: 23441827 DOI: 10.1111/micc.12051] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 02/19/2013] [Indexed: 11/27/2022]
Abstract
The classical model of metabolic regulation of blood flow in muscle tissue implies the maintenance of basal tone in arterioles of resting muscle and their dilation in response to exercise and/or tissue hypoxia via the evoked production of vasodilator metabolites by myocytes. A century-long effort to identify specific metabolites responsible for explaining active and reactive hyperemia has not been successful. Furthermore, the metabolic theory is not compatible with new knowledge on the role of physiological radicals (e.g., nitric oxide, NO, and superoxide anion, O2 (-) ) in the regulation of microvascular tone. We propose a model of regulation in which muscle contraction and active hyperemia are considered the physiologically normal state. We employ the "bang-bang" or "on/off" regulatory model which makes use of a threshold and hysteresis; a float valve to control the water level in a tank is a common example of this type of regulation. Active bang-bang regulation comes into effect when the supply of oxygen and glucose exceeds the demand, leading to activation of membrane NADPH oxidase, release of O2 (-) into the interstitial space and subsequent neutralization of the interstitial NO. Switching arterioles on/off when local blood flow crosses the threshold is realized by a local cell circuit with the properties of a bang-bang controller, determined by its threshold, hysteresis, and dead-band. This model provides a clear and unambiguous interpretation of the mechanism to balance tissue demand with a sufficient supply of nutrients and oxygen.
Collapse
Affiliation(s)
- Aleksander S Golub
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA.
| | | |
Collapse
|
14
|
Abstract
The cellular metabolism of oxygen generates potentially deleterious reactive oxygen species, including superoxide anion, hydrogen peroxide and hydroxyl radical. Under normal physiologic conditions, the rate and magnitude of oxidant formation is balanced by the rate of oxidant elimination. However, an imbalance between pro-oxidants and antioxidants results in oxidative stress, which is the pathogenic outcome of the overproduction of oxidants that overwhelms the cellular antioxidant capacity. There is growing evidence that increased oxidative stress and associated oxidative damage are mediators of vascular injury in cardiovascular pathologies, including hypertension, atherosclerosis and ischemia-reperfusion. This development has evoked considerable interest because of the possibilities that therapies targeted against reactive oxygen intermediates by decreasing the generation of reactive oxygen species and/or by increasing availability of antioxidants may be useful in minimizing vascular injury. This review focuses on the vascular actions of reactive oxygen species, the role of oxidative stress in vascular damage in hypertension and the therapeutic potential of modulating oxygen radical bioavailability in hypertension. In particular, the following topics will be highlighted: chemistry and sources of reactive oxygen species, antioxidant defense mechanisms, signaling events mediated by reactive oxygen species, role of reactive oxygen species in hypertension and the putative therapeutic role of antioxidants in cardiovascular disease.
Collapse
Affiliation(s)
- Rhian M Touyz
- Clinical Research Institute of Montreal, Quebec, Canada.
| |
Collapse
|
15
|
Affiliation(s)
- Aleksander S Golub
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia
| | | |
Collapse
|
16
|
Abstract
Based on mosaic theory, hypertension is a multifactorial disorder that develops because of genetic, environmental, anatomical, adaptive neural, endocrine, humoral, and hemodynamic factors. It has been recently proposed that oxidative stress may contribute to all of these factors and production of reactive oxygen species (ROS) play an important role in the development of hypertension. Previous studies focusing on the role of vascular NADPH oxidases provided strong support of this concept. Although mitochondria represent one of the most significant sources of cellular ROS generation, the regulation of mitochondrial ROS generation in the cardiovascular system and its pathophysiological role in hypertension are much less understood. In this review, the role of mitochondrial oxidative stress in the pathophysiology of hypertension and cross talk between angiotensin II signaling, pathways involved in mechanotransduction, NADPH oxidases, and mitochondria-derived ROS are considered. The possible benefits of therapeutic strategies that have the potential to attenuate mitochondrial oxidative stress for the prevention/treatment of hypertension are also discussed.
Collapse
Affiliation(s)
- Sergey I Dikalov
- Division of Clinical Pharmacology, Free Radicals in Medicine Core, Vanderbilt University Medical Center, Nashville, Tennessee; and
| | | |
Collapse
|
17
|
Witman MAH, Fjeldstad AS, McDaniel J, Ives SJ, Zhao J, Barrett-O'Keefe Z, Nativi JN, Stehlik J, Wray DW, Richardson RS. Vascular function and the role of oxidative stress in heart failure, heart transplant, and beyond. Hypertension 2012; 60:659-68. [PMID: 22753215 PMCID: PMC3421053 DOI: 10.1161/hypertensionaha.112.193318] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Using flow-mediated vasodilation (FMD), reactive hyperemia, and an acute oral antioxidant cocktail (AOC; vitamins C and E and α-lipoic acid), this study aimed to provide greater insight into altered vascular function and the role of oxidative stress in chronic heart failure patients with reduced ejection fraction (HFrEF) and at several time points beyond heart transplantation (HTx). A total of 61 age-matched subjects (12 healthy controls, 14 New York Heart Association class II and III HFrEF, and 35 HTx recipients [<3 years post-HTx, 5-10 years post-HTx, and >14 years post-HTx]) ingested either placebo (PL) or an AOC before FMD and reactive hyperemia testing of the brachial artery. Vascular function, as measured by FMD, was not different among the controls (6.8±1.9%), recent <3-year post-HTx group (8.1±1.2%), and the 5- to 10-year post-HTx group (5.5±1.0%). However, PL FMD was lower in the HFrEF (4.5±0.7%) and in the >14-year post-HTx group (2.9±0.8%). The AOC increased plasma ascorbate levels in all of the groups but only increased FMD in the controls (PL, 6.8±1.9%; AOC, 9.2±1.0%) and >14-year post-HTx recipients (PL, 2.9±0.8%; AOC, 4.5±1.3%). There were no differences in reactive hyperemia in any of the groups with PL or AOC. This cross-sectional study reveals that, compared with controls, vascular function is blunted in HFrEF, is similar soon after HTx, but is decreased with greater time post-HTx with free radicals implicated in this progression.
Collapse
Affiliation(s)
- Melissa A H Witman
- Geriatric Research Education and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Atochin DN, Huang PL. Role of endothelial nitric oxide in cerebrovascular regulation. Curr Pharm Biotechnol 2012; 12:1334-42. [PMID: 21235451 DOI: 10.2174/138920111798280974] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Revised: 07/01/2010] [Accepted: 08/08/2010] [Indexed: 11/22/2022]
Abstract
Endothelial nitric oxide (NO) plays important roles in the vascular system. Animal models that show vascular dysfunction demonstrate the protective role of endothelial NO dependent pathways. This review focuses on the role of endothelial NO in the regulation of cerebral blood flow and vascular tone. We will discuss the importance of NO in cerebrovascular function using animal models with altered endothelial NO production under normal, ischemic and reperfusion conditions, as well as in hyperoxia. Pharmacological and genetic manipulations of the endothelial NO system demonstrate the essential roles of endothelial NO synthase in maintenance of vascular tone and cerebral perfusion under normal and pathological conditions.
Collapse
Affiliation(s)
- Dmitriy N Atochin
- Cardiovascular Research Center and Cardiology Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02129, USA.
| | | |
Collapse
|
19
|
Dobashi Y, Miyakawa Y, Yamamoto I, Amao H. Effects of intestinal microflora on superoxide dismutase activity in the mouse cecum. Exp Anim 2011; 60:133-9. [PMID: 21512268 DOI: 10.1538/expanim.60.133] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In the antioxidant defense system, superoxide dismutase (SOD) catalyzes the breakdown of superoxide into hydrogen peroxide and oxygen. In the cecum, the influence of intestinal microflora on SOD activity is unknown. In this study, we used germ-free (GF) mice to examine the effect of intestinal microflora on SOD activity in the cecum, and SOD activity was compared between GF and conventional (CV) mice. The activity of CuZnSOD and MnSOD was determined using the SOD Assay Kit-WST. Expressions of CuZnSOD mRNA and protein were determined by real-time PCR and western blot analyses, respectively. The activities of CuZnSOD and MnSOD were significantly higher in the ceca of GF IQI and FVB/N strain mice than in CV mice (P<0.01-0.05). The gene expressions of CuZnSOD mRNA in the ceca of GF mice were significantly higher than those in CV mice (P<0.05), and CuZnSOD protein expression showed similar tendencies. Consistent with the abovementioned results, the total SOD activity in conventionalized mice decreased to the level of total SOD activity observed in the ceca of CV mice. Furthermore, no differences between GF and CV mice were observed in the SOD activities in the liver and thymus. Our results suggest that the antioxidant defense system in the mouse cecum is influenced by the intestinal microflora that downregulate SOD activity.
Collapse
Affiliation(s)
- Yuu Dobashi
- Laboratory of Experimental Animal Science, Nippon Veterinary and Animal Science University, Musashino, Tokyo 180-8602, Japan
| | | | | | | |
Collapse
|
20
|
Abstract
Endothelial cells exert an enormous influence on blood vessels throughout the circulation, but their impact is particularly pronounced in the brain. New concepts have emerged recently regarding the role of this cell type and mechanisms that contribute to endothelial dysfunction and vascular disease. Activation of the renin-angiotensin system plays a prominent role in producing these abnormalities. Both oxidative stress and local inflammation are key mechanisms that underlie vascular disease of diverse etiology. Endogenous mechanisms of vascular protection are also present, including antioxidants, anti-inflammatory molecules, and peroxisome proliferator-activated receptor-γ. Despite their clear importance, studies of mechanisms that underlie cerebrovascular disease continue to lag behind studies of vascular biology in general. Identification of endogenous molecules and pathways that protect the vasculature may result in targeted approaches to prevent or slow the progression of vascular disease that causes stroke and contributes to the vascular component of dementia and Alzheimer's disease.
Collapse
Affiliation(s)
- Frank M Faraci
- Dept. of Internal Medicine, Carver College of Medicine, Univ. of Iowa, Iowa City, Iowa 52242-1081, USA.
| |
Collapse
|
21
|
Oxidative Stress, Free Radicals, and Cellular Damage. OXIDATIVE STRESS IN APPLIED BASIC RESEARCH AND CLINICAL PRACTICE 2011. [DOI: 10.1007/978-1-61779-071-3_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
|
22
|
Cipolla MJ, Godfrey JA, Wiegman MJ. The effect of ovariectomy and estrogen on penetrating brain arterioles and blood-brain barrier permeability. Microcirculation 2010; 16:685-93. [PMID: 19905968 DOI: 10.3109/10739680903164131] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE We investigated the effect of estrogen replacement on the structure and function of penetrating brain arterioles (PA) and blood-brain barrier (BBB) permeability. MATERIALS AND METHODS Female ovariectomized Sprague-Dawley rats were replaced with estradiol (E(2)) and estriol (E(3)) (OVX + E; N=13) and compared to ovariectomized animals without replacement (OVX; N=14) and intact controls (CTL, proestrous; N=13). Passive and active diameters, percent tone, and passive distensibility of pressurized PA were compared. In addition, BBB permeability to Lucifer Yellow, a marker of transcellular transport, was compared in cerebral arteries. RESULTS Ovariectomy increased myogenic tone in PA, compared to CTL, that was not ameliorated by estrogen treatment. Percent tone at 75 mmHg for CTL vs. OVX and OVX + E was 44+/-3% vs. 51+/-1% and 54+/-3% (P<0.01 vs. CTL for both). No differences were found in passive diameters or distensibility between the groups. BBB permeability increased 500% in OVX vs. CTL animals; however, estrogen replacement restored barrier properties: flux of Lucifer Yellow for CTL, OVX, and OVX + E was (ng/mL): 3.4+/-1.2, 20.2+/-5.3 (P<0.01 vs. CTL), and 6.15+/-1.2 (n.s.). CONCLUSIONS These results suggest that estrogen replacement may not be beneficial for small-vessel disease in the brain, but may limit BBB disruption and edema under conditions that cause it.
Collapse
Affiliation(s)
- Marilyn J Cipolla
- Department of Neurology, University of Vermont, Burlington, Vermont, USA. Marilyn.
| | | | | |
Collapse
|
23
|
Prieto Peres MF, Valença MM. Headache endocrinological aspects. HANDBOOK OF CLINICAL NEUROLOGY 2010; 97:717-37. [PMID: 20816466 DOI: 10.1016/s0072-9752(10)97060-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this chapter we review the current understanding of how hormones, neurohormones, and neurotransmitters participate in the pain modulation of primary headaches. Stressful conditions and hormones intimately implicated in headache neurobiology are also discussed. With the recent progress in neuroimaging techniques and the development of animal models to study headache mechanisms, the physiopathology of several of the primary headaches is starting to be better understood. Various clinical characteristics of the primary headaches, such as pain, autonomic disturbances, and behavioral changes, are linked to hypothalamic brainstem activation and hormonal influence. Headache is greatly influenced by the circadian circle. Over the millennia the nervous system has evolved to meet changing environmental conditions, including the light-dark cycle, in order to ensure survival and reproduction. The main elements for synchronization between internal biological events and the external environment are the pineal gland and its main secretory product, melatonin. Melatonin is believed to be a significant element in migraine and in other headache disorders, which has implications for treatment. A potential therapeutic use of melatonin has been considered in several headache syndromes. In short, primary headaches are strongly influenced by physiological hormonal fluctuations, when nociceptive and non-nociceptive pathways are differentially activated to modulate the perception of pain.
Collapse
|
24
|
Lee BY, Al-Waili N, Stubbs D, Wendell K, Butler G, Al-Waili T, Al-Waili A. Ultra-low microcurrent in the management of diabetes mellitus, hypertension and chronic wounds: report of twelve cases and discussion of mechanism of action. Int J Med Sci 2009; 7:29-35. [PMID: 20046232 PMCID: PMC2792735 DOI: 10.7150/ijms.7.29] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Accepted: 09/10/2009] [Indexed: 02/06/2023] Open
Abstract
Oxidative stress plays a major role in the pathogenesis of both types of diabetes mellitus and cardiovascular diseases including hypertension. The low levels of antioxidants accompanied by raised levels of markers of free radical damage play a major role in delaying wound healing. Ultra-low microcurrent presumably has an antioxidant effect, and it was shown to accelerate wound healing. The purpose of the study is to investigate the efficacy of ultra-low microcurrent delivered by the Electro Pressure Regeneration Therapy (EPRT) device (EPRT Technologies-USA, Simi Valley, CA) in the management of diabetes, hypertension and chronic wounds. The EPRT device is an electrical device that sends a pulsating stream of electrons in a relatively low concentration throughout the body. The device is noninvasive and delivers electrical currents that mimic the endogenous electric energy of the human body. It is a rechargeable battery-operated device that delivers a direct current (maximum of 3 milliAmperes) of one polarity for 11.5 minutes, which then switched to the opposite polarity for another 11.5 minutes. The resulting cycle time is approximately 23min or 0.000732 Hz and delivers a square wave bipolar current with a voltage ranging from 5V up to a maximum of 40 V. The device produces a current range of 3 mA down to 100 nA. Twelve patients with long standing diabetes, hypertension and unhealed wounds were treated with EPRT. The patients were treated approximately for 3.5 h/day/5 days a week. Assessment of ulcer was based on scale used by National Pressure Ulcer Advisory Panel Consensus Development Conference. Patients were followed-up with daily measurement of blood pressure and blood glucose level, and their requirement for medications was recorded. Treatment continued from 2-4 months according to their response. Results showed that diabetes mellitus and hypertension were well controlled after using this device, and their wounds were markedly healed (30-100%). The patients either reduced their medication or completely stopped after the course of treatment. No side effects were reported. The mechanism of action was discussed.
Collapse
Affiliation(s)
- Bok Y Lee
- Department of Surgery, New York Medical College, Valhalla, New York, USA.
| | | | | | | | | | | | | |
Collapse
|
25
|
Roberts TJM, Chapman AC, Cipolla MJ. PPAR-gamma agonist rosiglitazone reverses increased cerebral venous hydraulic conductivity during hypertension. Am J Physiol Heart Circ Physiol 2009; 297:H1347-53. [PMID: 19666838 DOI: 10.1152/ajpheart.00630.2009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists have been shown to protect the cerebral vasculature, including the blood-brain barrier. In the present study, we investigated the effect of the PPAR-gamma agonist rosiglitazone on changes in venous permeability during chronic hypertension induced by nitric oxide synthase inhibition. Female Sprague-Dawley rats were either treated with N(G)-nitro-L-arginine methyl ester (L-NAME; 0.5 g/l in drinking water) for 5 wk (HTN; n = 8), L-NAME for 5 wk plus the PPAR-gamma agonist rosiglitazone (20 mg/kg in food) for the last 3 wk (HTN + Rosi; n = 5), L-NAME for 5 wk plus the superoxide dismutase mimetic Tempol (1 mmol/l in drinking water) for the last 3 wk (HTN + Tempol; n = 8), or were untreated controls (n = 9). Fluid filtration (J(v)/S) and hydraulic conductivity (L(p)) of cerebral veins were compared in vitro between groups after a step increase in pressure from 10 to 25 mmHg to mimic the change in hydrostatic pressure during acute hypertension. Hypertension increased J(v)/S by 2.2-fold and L(p) by 3.2-fold. Rosiglitazone treatment after 2 wk of hypertension completely reversed the increased J(v)/S and L(p) that occurred during hypertension, whereas Tempol had no effect. These results demonstrate that rosiglitazone was effective at reversing changes in venous permeability that occurred during chronic hypertension, an effect that does not appear to be related to its antioxidant properties. Our findings suggest that PPAR-gamma may be a key regulator of blood-brain barrier permeability and a potential therapeutic target during hypertension.
Collapse
Affiliation(s)
- Tim J M Roberts
- 1Departments of Neurology, Obstetrics, Gynecology and Reproductive Sciences, and Pharmacology, University of Vermont, Burlington, Vermont 05405, USA
| | | | | |
Collapse
|
26
|
Csiszar A, Lehoux S, Ungvari Z. Hemodynamic forces, vascular oxidative stress, and regulation of BMP-2/4 expression. Antioxid Redox Signal 2009; 11:1683-97. [PMID: 19320562 PMCID: PMC2842584 DOI: 10.1089/ars.2008.2401] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Changes in the hemodynamic environment (e.g., hypertension, disturbed-flow conditions) are known to promote atherogenesis by inducing proinflammatory phenotypic alterations in endothelial and smooth muscle cells; however, the mechanisms underlying mechanosensitive induction of inflammatory gene expression are not completely understood. Bone morphogenetic protein-2 and -4 (BMP-2/4) are TGF-beta superfamily cytokines that are expressed by both endothelial and smooth muscle cells and regulate a number of cellular processes involved in atherogenesis, including vascular calcification and endothelial activation. This review considers how hemodynamic forces regulate BMP-2/4 expression and explores the role of mechanosensitive generation of reactive oxygen species by NAD(P)H oxidases in the control of BMP signaling.
Collapse
Affiliation(s)
- Anna Csiszar
- Department of Physiology, New York Medical College, Valhalla, New York, USA
| | | | | |
Collapse
|
27
|
Brouns R, De Deyn PP. The complexity of neurobiological processes in acute ischemic stroke. Clin Neurol Neurosurg 2009; 111:483-95. [PMID: 19446389 DOI: 10.1016/j.clineuro.2009.04.001] [Citation(s) in RCA: 372] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 04/04/2009] [Accepted: 04/06/2009] [Indexed: 01/24/2023]
Abstract
There is an urgent need for improved diagnostics and therapeutics for acute ischemic stroke. This is the focus of numerous research projects involving in vitro studies, animal models and clinical trials, all of which are based on current knowledge of disease mechanisms underlying acute focal cerebral ischemia. Insight in the chain of events occurring during acute ischemic injury is essential for understanding current and future diagnostic and therapeutic approaches. In this review, we summarize the actual knowledge on the pathophysiology of acute ischemic stroke. We focus on the ischemic cascade, which is a complex series of neurochemical processes that are unleashed by transient or permanent focal cerebral ischemia and involves cellular bioenergetic failure, excitotoxicity, oxidative stress, blood-brain barrier dysfunction, microvascular injury, hemostatic activation, post-ischemic inflammation and finally cell death of neurons, glial and endothelial cells.
Collapse
Affiliation(s)
- R Brouns
- Department of Neurology and Memory Clinic, Middelheim General Hospital, Antwerp, Belgium
| | | |
Collapse
|
28
|
Oral antioxidants and cardiovascular health in the exercise-trained and untrained elderly: a radically different outcome. Clin Sci (Lond) 2009; 116:433-41. [PMID: 18795893 DOI: 10.1042/cs20080337] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Both antioxidant supplementation and exercise training have been identified as interventions which may reduce oxidative stress and thus improve cardiovascular health, but the interaction of these interventions on arterial BP (blood pressure) and vascular function has not been studied in older humans. Thus in six older (71+/-2 years) mildly hypertensive men, arterial BP was evaluated non-invasively at rest and during small muscle mass (knee-extensor) exercise with and without a pharmacological dose of oral antioxidants (vitamins C and E, and alpha-lipoic acid). The efficacy of the antioxidant intervention to decrease the plasma free radical concentration was verified via EPR (electron paramagnetic resonance) spectroscopy, while changes in endothelial function in response to exercise training and antioxidant administration were evaluated via FMD (flow-mediated vasodilation). Subjects were re-evaluated after a 6-week aerobic exercise training programme. Prior to training, acute antioxidant administration did not change resting arterial BP or FMD. Six weeks of knee-extensor exercise training reduced systolic BP (from 150+/-8 mmHg at pre-training to 138+/-3 mmHg at post-training) and diastolic BP (from 91+/-5 mmHg at pre-training to 79+/-3 mmHg at post-training), and improved FMD (1.5+/-1 to 4.9+/-1% for pre- and post-training respectively). However, antioxidant administration after exercise training negated these improvements, returning subjects to a hypertensive state and blunting training-induced improvements in FMD. In conclusion, the paradoxical effects of these interventions suggest a need for caution when exercise and acute antioxidant supplementation are combined in elderly mildly hypertensive individuals.
Collapse
|
29
|
Chrissobolis S, Faraci FM. The role of oxidative stress and NADPH oxidase in cerebrovascular disease. Trends Mol Med 2008; 14:495-502. [PMID: 18929509 DOI: 10.1016/j.molmed.2008.09.003] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 09/01/2008] [Accepted: 09/01/2008] [Indexed: 02/07/2023]
Abstract
The study of reactive oxygen species (ROS) and oxidative stress remains a very active area of biological research, particularly in relation to cellular signaling and the role of ROS in disease. In the cerebral circulation, oxidative stress occurs in diverse forms of disease and with aging. Within the vessel wall, ROS produce complex structural and functional changes that have broad implications for regulation of cerebral perfusion and permeability of the blood-brain barrier. These oxidative-stress-induced changes are thought to contribute to the progression of cerebrovascular disease. Here, we highlight recent findings in relation to oxidative stress in the cerebral vasculature, with an emphasis on the emerging role for NADPH oxidases as a source of ROS and the role of ROS in models of disease.
Collapse
Affiliation(s)
- Sophocles Chrissobolis
- Departments of Internal Medicine and Pharmacology, Division of Cardiovascular Diseases, Cardiovascular Center, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA
| | | |
Collapse
|
30
|
Valença MM, Andrade-Valença LPA, Bordini CA, Speciali JG. Thunderclap headache attributed to reversible cerebral vasoconstriction: view and review. J Headache Pain 2008; 9:277-88. [PMID: 18668199 PMCID: PMC3452202 DOI: 10.1007/s10194-008-0054-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Accepted: 06/20/2008] [Indexed: 11/02/2022] Open
Abstract
Thunderclap headache attributed to reversible cerebral vasoconstriction (THARCV) is a syndrome observed in a number of reported cases. In this article we reviewed this new headache entity (idiopathic form) using the clinical-radiological findings of 25 reported patients. In this series of patients 72% were women, the mean age at the onset of first headache episode was 39.4 +/- 2.3 years. In addition to the sine qua non condition of being abrupt and severe (thunderclap) at the onset, the headache was usually described as being explosive, excruciating, or crushing. The feature of pulsatility, accompanied or not by nausea was described by 80% of the patients. Forty percent of the cases manifested vomiting and 24% photophobia. Usually the headache was generalized, and in three cases it was unilateral at least at the onset. In 21 of 25 patients (84%) there was at least one recurrence or a sudden increase in the intensity of the headache. A past history of migraine was present in 52% of the patients. Precipitating factors were identified in 56% of the patients. Sexual intercourse was described by six patients. Of the 25 patients with THARCV syndrome studied, 12 (48%) developed focal neurological signs, transitory ischemic attack (n = 1), or ischemic stroke (n = 11, 44%), and two (8%) of them manifested seizures. The THARCV syndrome is a neurological disturbance perhaps more frequent than expected, preferentially affecting middle aged female migraineurs, and having an unpredictable prognosis, either showing a benign course or leading to stroke.
Collapse
Affiliation(s)
- Marcelo M Valença
- Division of Neurology and Neurosurgery, Department of Neuropsychiatry, Federal University of Pernambuco, Recife, PE, Brazil.
| | | | | | | |
Collapse
|
31
|
Richardson RS, Donato AJ, Uberoi A, Wray DW, Lawrenson L, Nishiyama S, Bailey DM. Exercise-induced brachial artery vasodilation: role of free radicals. Am J Physiol Heart Circ Physiol 2007; 292:H1516-22. [PMID: 17114239 DOI: 10.1152/ajpheart.01045.2006] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Originally thought of as simply damaging or toxic “accidents” of in vivo chemistry, free radicals are becoming increasingly recognized as redox signaling molecules implicit in cellular homeostasis. Indeed, at the vascular level, it is plausible that oxidative stress plays a regulatory role in normal vascular function. Using electron paramagnetic resonance (EPR) spectroscopy, we sought to document the ability of an oral antioxidant cocktail (vitamins C, E, and α-lipoic acid) to reduce circulating free radicals, and we employed Doppler ultrasound to examine the consequence of an antioxidant-mediated reduction in oxidative stress on exercise-induced vasodilation. A total of 25 young (18–31 yr) healthy male subjects partook in these studies. EPR spectroscopy revealed a reduction in circulating free radicals following antioxidant administration at rest (∼98%) and as a consequence of exercise (∼85%). Plasma total antioxidant capacity and vitamin C both increased following the ingestion of the antioxidant cocktail, whereas vitamin E levels were not influenced by the ingestion of the antioxidants. Brachial artery vasodilation during submaximal forearm handgrip exercise was greater with the placebo (7.4 ± 1.8%) than with the antioxidant cocktail (2.3 ± 0.7%). These data document the efficacy of an oral antioxidant cocktail in reducing free radicals and suggest that, in a healthy state, the aggressive disruption of the delicate balance between pro- and antioxidant forces can negatively impact vascular function. These findings implicate an exercise-induced reliance upon pro-oxidant-stimulated vasodilation, thereby revealing an important and positive vascular role for free radicals.
Collapse
Affiliation(s)
- Russell S Richardson
- Dept of Medicine, Physiology Division, Univ of California San Diego, La Jolla, CA 92093-0623, USA.
| | | | | | | | | | | | | |
Collapse
|
32
|
Christensen FH, Hansen T, Stankevicius E, Buus NH, Simonsen U. Elevated pressure selectively blunts flow-evoked vasodilatation in rat mesenteric small arteries. Br J Pharmacol 2006; 150:80-7. [PMID: 17128286 PMCID: PMC2013851 DOI: 10.1038/sj.bjp.0706965] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND AND PURPOSE The present study investigated mechanisms underlying impaired endothelium-dependent vasodilatation elicited by elevating the intraluminal pressure in rat mesenteric small arteries. EXPERIMENTAL APPROACH Arterial segments (internal diameter 316+/-2 microm, n=86) were mounted in a pressure myograph. The effect of elevating pressure from 50 to 120 mmHg for 1 h before resetting it to 50 mmHg was studied on endothelium-dependent vasodilatation. KEY RESULTS In arteries constricted with U46619 in the presence of indomethacin, shear stress generated by flow, evoked vasodilatation that was abolished by an inhibitor of nitric oxide (NO) synthase, asymmetric dimethylarginine (1 mM), whereas acetylcholine-induced vasodilatation was unchanged. After elevation of intraluminal pressure for 1 h and then resetting it to 50 mmHg, vasodilatation induced by shear stress and the NO donor, S-nitrosopenicillamine was inhibited, while vasodilatation induced by a guanylyl cyclase activator, BAY 412272, and acetylcholine was unaltered. Superoxide levels sensitive to polyethylene glycol superoxide dismutase were increased in segments exposed to elevated pressure. A superoxide scavenger, tempol (300 microM), a general endothelin receptor antagonist, SB 217242 and the selective ET(A) receptor antagonist, BQ 123 preserved shear stress-evoked vasodilatation. CONCLUSIONS AND IMPLICATIONS The present study shows that transient exposure to an elevated intraluminal pressure selectively inhibits flow-evoked NO-mediated vasodilatation, probably through activation of endothelin receptors and increased formation of superoxide. In contrast, elevation of pressure did not affect the acetylcholine-evoked endothelium-derived hyperpolarizing factor type vasodilatation in mesenteric small arteries.
Collapse
Affiliation(s)
- F H Christensen
- Department of Pharmacology, University of Aarhus, 8000 Aarhus C, Denmark
| | | | | | | | | |
Collapse
|
33
|
Ungvari Z, Wolin MS, Csiszar A. Mechanosensitive production of reactive oxygen species in endothelial and smooth muscle cells: role in microvascular remodeling? Antioxid Redox Signal 2006; 8:1121-9. [PMID: 16910760 DOI: 10.1089/ars.2006.8.1121] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Changes in the hemodynamic environment (e.g., hypertension, increased blood flow/shear stress) are known to lead to vascular remodeling; however, the underlying mechanisms by which hemodynamic forces control gene expression in vascular cells are not yet completely understood. This review considers how mechanosensitive generation of reactive oxygen species (ROS) by NAD(P)H oxidases and other sources interacts with downstream signaling systems [including activation of nuclear factor kappa B (NF-kappaB) and AP-1] that modulate the phenotype of endothelial and smooth muscle cells, leading to vascular remodeling. We propose a model for an interaction between direct mechanosensitive ROS signaling and pathways activated by pressure-induced upregulation of prooxidant paracrine signaling mechanisms [local renin-angiotensin system, TNF-alpha- converting enzyme (TACE)/tumor necrosis factor alpha (TNF-alpha) system, and endothelin signaling].
Collapse
Affiliation(s)
- Zoltan Ungvari
- Department of Physiology, New York Medical College, Valhalla, 10595, USA.
| | | | | |
Collapse
|
34
|
Mashiba J, Koike G, Kamiunten H, Ikeda M, Sunagawa K. Vasospastic angina and microvascular angina are differentially influenced by PON1 A632G polymorphism in the Japanese. Circ J 2006; 69:1466-71. [PMID: 16308493 DOI: 10.1253/circj.69.1466] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Ethnicity and smoking are well-known risk factors for the pathogenesis of coronary vasospasm. Oxidative stress induced by smoking plays a crucial role in coronary vasospasm, but is not enough to account for the pathogenesis of coronary vasospasm, indicating that genetic factors are strongly involved. METHODS AND RESULTS The study group comprised 162 vasospastic angina patients (VSAs), 61 microvascular angina patients (MVAs) and 61 non-responders (NRs) diagnosed by acetylcholine provocation test. Four polymorphisms of the oxidative stress related genes, cytochrome b-245, alpha polypeptide gene (CYBA) C242T and A640G, paraoxonase 1 gene (PON1) A632G, phospholipase A2 group VII gene (PLA2G7) G994T were genotyped. Allele frequency of PON1 632-G was significantly higher in both the VSA with dominant fashion and the MVA with recessive fashion compared with NR. This association was strongly influenced by gender in the MVA only. There were no significant associations between the other polymorphisms and coronary vasospasm. In addition, the allele frequency of PON1 632-G in the Japanese was higher than in Caucasians. CONCLUSIONS There was a significant association between PON1 A632G polymorphism and MVA as well as VSA, but the impact of this on VSA and MVA is different in the Japanese.
Collapse
Affiliation(s)
- Junko Mashiba
- Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | | | | | | | | |
Collapse
|
35
|
Aikawa K, Saitoh SI, Muto M, Osugi T, Matsumoto K, Onogi F, Maehara K, Yaoita H, Maruyama Y. Effects of antioxidants on coronary microvascular spasm induced by epicardial coronary artery endothelial injury in pigs. Coron Artery Dis 2005; 15:21-30. [PMID: 15201617 DOI: 10.1097/00019501-200402000-00004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The effect of oxidative stress on coronary microvascular disease is unknown. We investigated whether chronic administration of ascorbic acid (ASC) or glutathione (GSH) prevents microvascular dysfunction and remodeling induced by upstream repeated coronary artery endothelial injury. METHODS Balloon endothelial injury was repeated at the left anterior descending coronary artery (LAD), just distal to an implanted flow meter, every 2 weeks for 6 weeks in pigs. Changes in LAD blood flow induced by acetylcholine (ACh) and 5-hydroxytryptamine were assessed before each endothelial injury and at 8 weeks after the first endothelial injury in pigs without treatment (endothelial injury group, n = 12) and in pigs treated with oral ASC (3 g/day) (ASC group, n = 12) and ASC (3 g/day) plus GSH (1 g/day) (ASC + GSH group, n = 12). RESULTS In the endothelial injury group, reduced blood flow in response to ACh was augmented from a decrease of 18 +/- 17% to a decrease of 100% (that is, zero flow, 8 weeks, P < 0.01), accompanied by an increase of ascorbyl free radicals (AFRs) in coronary sinus blood. In contrast, in the ASC + GSH group, blood flow response to ACh was altered to a decrease of 45 +/- 17% (8 weeks, P < 0.01 compared with the endothelial injury group), coronary sinus blood AFRs did not change (8 weeks, 21.4 +/- 12.5 signal intensities, P < 0.01 compared with the endothelial injury group) and the rate of platelet aggregation induced by adenosine diphosphate was small (8 weeks, 56 +/- 17%, P < 0.01 compared with the endothelial injury group). CONCLUSIONS Chronic administration of antioxidants suppressed microvascular hypercontraction, suggesting that it may be a promising therapeutic strategy for treating coronary microvessel disorders, including microvascular angina.
Collapse
Affiliation(s)
- Kazuhiko Aikawa
- First Department of Internal Medicine, Fukushima Medical University, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Blackwell KA, Sorenson JP, Richardson DM, Smith LA, Suda O, Nath K, Katusic ZS. Mechanisms of aging-induced impairment of endothelium-dependent relaxation: role of tetrahydrobiopterin. Am J Physiol Heart Circ Physiol 2004; 287:H2448-53. [PMID: 15319209 DOI: 10.1152/ajpheart.00248.2004] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Oxidative stress has been implicated as an important mechanism of vascular endothelial dysfunction induced by aging. Previous studies suggested that tetrahydrobiopterin (BH4), an essential cofactor of endothelial NO synthase, could be a molecular target for oxidation. We tested the hypothesis that oxidative stress, in particular oxidation of BH4, may contribute to attenuation of endothelium-dependent relaxation in aged mice. Vasomotor function of isolated carotid arteries was studied using a video dimension analyzer. Vascular levels of BH4 and its oxidation products were measured via HPLC. In aged mice (age, 95 +/- 2 wk), endothelium-dependent relaxation to ACh (10(-5) to 10(-9) M) as well as endothelium-independent relaxation to the NO donor diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate (DEA-NONOate, 10(-5) to 10(-9) M) were significantly reduced compared with relaxation detected in young mice (age, 23 +/- 0.5 wk). Incubation of aged mouse carotid arteries with the cell-permeable SOD mimetic Mn(III)tetra(4-benzoic acid)porphyrin chloride normalized relaxation to ACh and DEA-NONOate. Furthermore, production of superoxide anion in aorta and serum levels of amyloid P component, which is the murine analog of C-reactive protein, was increased in old mice. In aorta, neither the concentration of BH4 nor the ratio of reduced BH4 to the oxidation products were different between young and aged mice. Our results demonstrate that in mice, aging impairs relaxation mediated by NO most likely by increased formation of superoxide anion. Oxidation of BH4 does not appear to be an important mechanism underlying vasomotor dysfunction in aged mouse arteries.
Collapse
Affiliation(s)
- Katherine A Blackwell
- Department of Anesthesia Research and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
| | | | | | | | | | | | | |
Collapse
|
37
|
Abstract
This review focuses on the role of oxidative processes in atherosclerosis and its resultant cardiovascular events. There is now a consensus that atherosclerosis represents a state of heightened oxidative stress characterized by lipid and protein oxidation in the vascular wall. The oxidative modification hypothesis of atherosclerosis predicts that low-density lipoprotein (LDL) oxidation is an early event in atherosclerosis and that oxidized LDL contributes to atherogenesis. In support of this hypothesis, oxidized LDL can support foam cell formation in vitro, the lipid in human lesions is substantially oxidized, there is evidence for the presence of oxidized LDL in vivo, oxidized LDL has a number of potentially proatherogenic activities, and several structurally unrelated antioxidants inhibit atherosclerosis in animals. An emerging consensus also underscores the importance in vascular disease of oxidative events in addition to LDL oxidation. These include the production of reactive oxygen and nitrogen species by vascular cells, as well as oxidative modifications contributing to important clinical manifestations of coronary artery disease such as endothelial dysfunction and plaque disruption. Despite these abundant data however, fundamental problems remain with implicating oxidative modification as a (requisite) pathophysiologically important cause for atherosclerosis. These include the poor performance of antioxidant strategies in limiting either atherosclerosis or cardiovascular events from atherosclerosis, and observations in animals that suggest dissociation between atherosclerosis and lipoprotein oxidation. Indeed, it remains to be established that oxidative events are a cause rather than an injurious response to atherogenesis. In this context, inflammation needs to be considered as a primary process of atherosclerosis, and oxidative stress as a secondary event. To address this issue, we have proposed an "oxidative response to inflammation" model as a means of reconciling the response-to-injury and oxidative modification hypotheses of atherosclerosis.
Collapse
Affiliation(s)
- Roland Stocker
- Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia.
| | | |
Collapse
|
38
|
Fabian RH, Perez-Polo JR, Kent TA. Extracellular superoxide concentration increases following cerebral hypoxia but does not affect cerebral blood flow. Int J Dev Neurosci 2004; 22:225-30. [PMID: 15245758 DOI: 10.1016/j.ijdevneu.2004.03.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Revised: 03/23/2004] [Accepted: 03/24/2004] [Indexed: 11/17/2022] Open
Abstract
Abnormalities of cerebral blood flow during and following hypoxia and ischemia contribute to the progression of tissue injury. Oxidative stress during and following hypoxia is known to markedly increase superoxide anion concentration. There is conflicting evidence that the concentration of superoxide anion regulates cerebral blood flow through its effect on vascular tone, although difficulties in measurement of superoxide anion complicate these studies. In order to test the hypothesis that changes in cerebral blood flow during and following hypoxia are due to changes in extracellular superoxide anion levels, we examined tissue oxygen levels by fiberoptic oximetry and superoxide anion levels using a previously validated cytochrome c coated electrode on the cortical surface and correlated these measurements to cerebral blood flow measured by laser Doppler in rats subjected to 20 min of hypoxia followed by hyperoxic reoxygenation recovery. The results showed a burst of superoxide anion with the onset of reoxygenation that temporally correlated with a transient peak in tissue oxygen tension lasting 10 min. and was eliminated by pretreatment with Cu-Zn superoxide dismutase conjugated to polyethylene glycol. Cerebral blood flow did not differ during hypoxia or recovery in the polyethylene glycol conjugated superoxide dismutase and control treatment groups. This study demonstrated no effect of increased superoxide anion concentration on cerebral blood flow during hyperoxic recovery following hypoxia.
Collapse
Affiliation(s)
- Roderic H Fabian
- Department of Neurology, University of Texas Medical Branch, Galveston, TX 77030, USA.
| | | | | |
Collapse
|
39
|
Ungvari Z, Csiszar A, Kaminski PM, Wolin MS, Koller A. Chronic high pressure-induced arterial oxidative stress: involvement of protein kinase C-dependent NAD(P)H oxidase and local renin-angiotensin system. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 165:219-26. [PMID: 15215177 PMCID: PMC1618527 DOI: 10.1016/s0002-9440(10)63290-7] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Regardless of the underlying pathological mechanisms oxidative stress seems to be present in all forms of hypertension. Thus, we tested the hypothesis that chronic presence of high pressure itself elicits increased arterial O(2)(.-) production. Hypertension was induced in rats by abdominal aortic banding (Ab). Rats with Ab had elevated pressure in vessels proximal and normal pressure in vessels distal to the coarctation, yet both vascular beds were exposed to the same circulating factors. Compared to normotensive hind limb arteries (HLAs) hypertensive forelimb arteries (FLAs) exhibited 1) impaired dilations to acetylcholine and the nitric oxide donor S-nitroso-N-acetyl-D,L-penicillamine that were restored by administration of superoxide dismutase; 2) an increased production of O(2)(.-) (measured by lucigenin chemiluminescence and ethidium bromide fluorescence) that was inhibited or reduced by superoxide dismutase, the NAD(P)H oxidase inhibitors diphenyleneiodonium and apocynin, or the protein kinase C (PKC) inhibitors chelerythrine and staurosporine or by the angiotensin-converting enzyme (ACE) inhibitor captopril; and 3) increased ACE activity. In organ culture, exposure of isolated arteries of normotensive rats to high pressure (160 mmHg, for 24 hours) significantly increased O(2)(.-) production compared to that in arteries exposed to 80 mmHg. High pressure-induced O(2)(.-) generation was reduced by inhibitors of ACE and PKC. Incubation of cultured arteries with angiotensin II elicited significantly increased O(2)(.-) generation that was inhibited by chelerythrine. Thus, we propose that chronic presence of high pressure itself can elicit arterial oxidative stress, primarily by activating directly a PKC-dependent NAD(P)H oxidase pathway, but also, in part, via activation of the local renin-angiotensin system.
Collapse
Affiliation(s)
- Zoltan Ungvari
- Department of Physiology, Basic Sciences Building, New York Medical College, Valhalla, NY 10595, USA
| | | | | | | | | |
Collapse
|
40
|
Veerareddy S, Cooke CLM, Baker PN, Davidge ST. Gender differences in myogenic tone in superoxide dismutase knockout mouse: animal model of oxidative stress. Am J Physiol Heart Circ Physiol 2004; 287:H40-5. [PMID: 14975934 DOI: 10.1152/ajpheart.01179.2003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Oxidative stress mediated by prooxidants has been implicated in the pathogenesis of vascular disorders. However, the effect of prooxidants on myogenic regulation of vascular function and the differential influence of gender is not known. SOD, an intracellular enzyme, restricts excess prooxidant levels and may limit vascular dysfunction. We therefore tested the effects of Cu,Zn SOD deficiency on vascular tone in both male and female SOD knockout (SOD−/−) mice. We hypothesized that myogenic tone would be enhanced in SOD−/− mice by excess prooxidants compared with wild-type control mice. Indeed, resistance-sized mesenteric arteries from SOD−/− mice exhibited enhanced myogenic tone compared with control mice. Myogenic tone was lower in female than male control mice. Interestingly, this gender effect was absent in SOD−/− mice, such that myogenic tone of mesenteric arteries from females was equated to that of arteries from males. Furthermore, the pathways that modulate myogenic tone were diverse. In both male and female control mice, inhibition of prostaglandin H synthase (PGHS) and nitric oxide synthase (NOS) pathways enhanced myogenic tone. In female SOD−/− mice, inhibition of PGHS and NOS pathways enhanced myogenic tone to a greater extent compared with control mice. Conversely, in male SOD−/− mice, NOS and PGHS inhibition did not alter tone and only inhibition of gap junctions enhanced myogenic tone. In conclusion, this study revealed enhanced myogenic tone in SOD−/− mice compared with control mice. Furthermore, Cu,Zn SOD deficiency particularly enhanced myogenic tone in female mice such that their vascular tone attained the level of male SOD−/− mice, possibly mediated by prooxidants.
Collapse
Affiliation(s)
- Sukrutha Veerareddy
- Perinatal Research Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
| | | | | | | |
Collapse
|
41
|
Cuzzocrea S, Mazzon E, Dugo L, Di Paola R, Caputi AP, Salvemini D. Superoxide: a key player in hypertension. FASEB J 2004; 18:94-101. [PMID: 14718390 DOI: 10.1096/fj.03-0428com] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Superoxide is increased in the vessel wall of spontaneously hypertensive rats (SHR) where, if "blocked," potentiates endothelium-dependent vasodilation. The purpose of this study was to determine the role of superoxide anion in hypertension and its interaction with nitric oxide (NO). For this purpose we used a low molecular weight synthetic superoxide dismutase mimetic (M40403), known to remove selectively superoxide anion. Baseline mean arterial pressure (MAP) was significantly elevated in the SHR compared with its normal counterpart, Wistar Kyoto (WKY). M40403 at a dose (2 mg x kg(-1) x h(-1)), which had no effect in the WKY, significantly decreased MAP in SHR rats. To determine whether superoxide anion increases MAP by inactivating NO, NO synthesis was blocked with N(G) nitro-arginine methyl ester (L-NAME, 3 mg/kg i.v.), a nonselective nitric oxide synthase inhibitor. L-NAME (3 mg/kg, i.v) blocked the anti-hypertensive effect of M40403 (2 mg/kg over 30 min). When used at a dose that yielded similar increases in MAP, norepinephrine (2.1 microg/kg) failed to alter the anti-hypertensive effects of M40403 in the SHR. To investigate whether the anti-hypertensive effect of M40403 was associated with an improvement of the alterations in vascular reactivity, a separate group of experiments was carried out ex vivo. Endothelium-dependent vasorelaxation to acetylcholine (10 nM-10 microM), an index of endothelial function, was reduced in aortic rings taken from SHR rats when compared with WKY rats. In vivo treatment with M40403 caused an improvement of the degree of the endothelial dysfunction in SHR rats. Furthermore, immunohistochemical analysis for nitrotyrosine (the product formed from the interaction of nitric oxide with superoxide) revealed a positive staining in aorta from SHR rats. The degree of staining for nitrotyrosine was markedly reduced in tissue sections obtained from SHR rats treated with M40403. Our data suggest that overt production of superoxide in SHR couples with nitric oxide, reducing its function and leading to a loss of blood vessel tone and hypertension. Another important effect appears to be at the level of endothelial cellular integrity, where by interacting with nitric oxide, superoxide anion forms peroxynitrite and subsequent endothelial cell dysfunction. By removing superoxide, M40403 restores blood pressure to near-to-normal values.
Collapse
|
42
|
Kazama K, Wang G, Frys K, Anrather J, Iadecola C. Angiotensin II attenuates functional hyperemia in the mouse somatosensory cortex. Am J Physiol Heart Circ Physiol 2003; 285:H1890-9. [PMID: 12907423 DOI: 10.1152/ajpheart.00464.2003] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated whether angiotensin II (ANG II), a peptide that plays a central role in the genesis of hypertension, alters the coupling between synaptic activity and cerebral blood flow (CBF), a critical homeostatic mechanism that assures adequate cerebral perfusion to active brain regions. The somatosensory cortex was activated by stroking the facial whiskers in anesthetized C57BL/6J mice while local CBF was recorded by laser-Doppler flowmetry. Intravenous ANG II infusion (0.25 mug.kg-1.min-1) increased mean arterial pressure (MAP) from 82 +/- 2 to 102 +/- 3 mmHg (P < 0.05) without affecting resting CBF (P > 0.05). ANG II attenuated the CBF increase produced by whisker stimulation by 65% (P < 0.05) but did not affect the response to hypercapnia or to neocortical application of the nitric oxide donor S-nitroso-N-acetyl penicillamine (P > 0.05). The effect of ANG II on functional hyperemia persisted if the elevation in MAP was offset by controlled hemorrhage or prevented by topical application of the peptide to the activated cortex. ANG II did not reduce the amplitude of the P1 wave of the field potentials evoked by whisker stimulation (P > 0.05). Infusion of phenylephrine increased MAP (P > 0.05 from ANG II) but did not alter the functional hyperemic response (P > 0.05). The data suggest that ANG II alters the coupling between CBF and neural activity. The mechanisms of the effect are not related to the elevation in MAP and/or to inhibition of the synaptic activity evoked by whisker stimulation. The imbalance between CBF and neural activity induced by ANG II may alter the homeostasis of the neuronal microenvironment and contribute to brain dysfunction during ANG II-induced hypertension.
Collapse
Affiliation(s)
- Ken Kazama
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, 411 E. 69th Street, Rm. KB410, New York, NY 10021, USA
| | | | | | | | | |
Collapse
|
43
|
Atochin DN, Demchenko IT, Astern J, Boso AE, Piantadosi CA, Huang PL. Contributions of endothelial and neuronal nitric oxide synthases to cerebrovascular responses to hyperoxia. J Cereb Blood Flow Metab 2003; 23:1219-26. [PMID: 14526232 DOI: 10.1097/01.wcb.0000089601.87125.e4] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hyperoxia causes a transient decrease in CBF, followed by a later rise. The mediators of these effects are not known. We used mice lacking endothelial or neuronal nitric oxide synthase (NOS) isoforms (eNOS-/- and nNOS-/- mice) to study the roles of the NOS isoforms in mediating changes in cerebral vascular tone in response to hyperoxia. Resting regional cerebral blood flow (rCBF) did not differ between wild type (WT), eNOS-/- mice, and nNOS-/- mice. eNOS-/- mice showed decreased cerebrovascular reactivities to NG-nitro-L-arginine methyl ester (L-NAME), PAPA NONOate, acetylcholine (Ach), and SOD1. In response to hyperbaric oxygen (HBO2) at 5 ATA, WT and nNOS-/- mice showed decreases in rCBF over 30 minutes, but eNOS-/- mice did not. After 60 minutes HBO2, rCBF increased more in WT mice than in eNOS-/- or nNOS-/- mice. Brain NO-metabolites (NOx) decreased in WT and eNOS-/- mice within 30 minutes of HBO2, but after 45 minutes, NOx rose above control levels, whereas they did not change in nNOS-/- mice. Brain 3NT increased during HBO2 in WT and eNOS-/- but did not change in nNOS-/- mice. These results suggest that modulation of eNOS-derived NO by HBO2 is responsible for the early vasoconstriction responses, whereas late HBO2-induced vasodilation depends upon both eNOS and nNOS.
Collapse
Affiliation(s)
- D N Atochin
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | | | | | | | | | | |
Collapse
|
44
|
Philip S, Armstead WM. Differential role of PTK, ERK and p38 MAPK in superoxide impairment of NMDA cerebrovasodilation. Brain Res 2003; 979:98-103. [PMID: 12850576 DOI: 10.1016/s0006-8993(03)02879-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Previous studies in piglets have shown that the generation of oxygen free radicals (O(-)(2)) following traumatic brain injury and hypoxia/ischemia contribute to the reversal of N-methyl-D-aspartate (NMDA)-induced pial artery dilation to vasoconstriction. This study determined the contribution of protein tyrosine kinase (PTK) and mitogen-activated protein (MAPK) activation to impairment of NMDA cerebrovasodilation by O(-)(2) in piglets equipped with a closed window. Exposure of the cerebral cortex to a xanthine oxidase O(-)(2) generating system (OX) reversed NMDA (10(-8), 10(-6) M) dilation to vasoconstriction but such impairment was partially prevented by the PTK inhibitor, genistein, the MAPK (ERK isoform) inhibitor, U0126, and the MAPK (p38 isoform) inhibitor, SB203580 (9+/-1 and 15+/-1 vs. -1+/-1 and -1+/-1 vs. 5+/-1 and 9+/-1% for sham control, OX and OX in the presence of genistein, respectively). However, the p38 MAPK inhibitor, SB203580, prevented NMDA dilator impairment significantly less than the ERK MAPK inhibitor, U0126. Similar results were obtained for glutamate. These data show that PTK and MAPK activation by the presence of O(-)(2) contributes to the impairment of NMDA dilation. Furthermore, these data indicate a differential role for ERK and p38 MAPK activation in impairment of NMDA dilation by O(-)(2) in the brain.
Collapse
Affiliation(s)
- Shaji Philip
- Department of Anesthesia, University of Pennsylvania, 3400 Spruce Street, 19104, Philadelphia, PA, USA
| | | |
Collapse
|
45
|
Ross J, Armstead WM. Differential role of PTK and ERK MAPK in superoxide impairment of K(ATP) and K(Ca) channel cerebrovasodilation. Am J Physiol Regul Integr Comp Physiol 2003; 285:R149-54. [PMID: 12793995 DOI: 10.1152/ajpregu.00003.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previously, superoxide (O2 -) has been observed to impair pial artery dilation (PAD) to activators of the ATP-sensitive (KATP) and calcium-sensitive (KCa) K+ channels. This study tested the hypothesis that activation of protein tyrosine kinase (PTK) and the ERK isoform of MAPK by O2 - contribute to impairment of KATP and KCa channel PAD. Exposure of the cerebral cortex to a xanthine oxidase O2 --generating system (OX) blunted PAD to cromakalim, a KATP agonist, but preadministration of genistein, a PTK antagonist, or U-0126, an ERK MAPK inhibitor, almost completely prevented such impairment (11 +/- 1 and 22 +/- 1 vs. 3 +/- 1 and 7 +/- 1 vs. 10 +/- 1 and 16 +/- 2% for cromakalim with 10-8 and 10-6 M PAD during control, OX, and OX + genistein conditions). In contrast, neither genistein nor U-0126 robustly protected PAD to NS-1619, a KCa agonist, after OX exposure (11 +/- 1 and 18 +/- 2 vs. 1 +/- 1 and 2 +/- 1 vs. 4 +/- 1 and 6 +/- 1% for 10-8 and 10-6 M NS-1619 during control, OX, and OX + genistein conditions). These data show that PTK and ERK MAPK activation contribute to O2 --induced KATP and KCa channel PAD impairment and suggest a differential greater role for PTK and ERK MAPK in KATP vs. KCa channel PAD impairment.
Collapse
Affiliation(s)
- John Ross
- Dept. of Anesthesia, Univ. of Pennsylvania, 3400 Spruce St., Philadelphia, PA 19104, USA
| | | |
Collapse
|
46
|
Shin HK, Lee JH, Kim CD, Kim YK, Hong JY, Hong KW. Prevention of impairment of cerebral blood flow autoregulation during acute stage of subarachnoid hemorrhage by gene transfer of Cu/Zn SOD-1 to cerebral vessels. J Cereb Blood Flow Metab 2003; 23:111-20. [PMID: 12500096 DOI: 10.1097/01.wcb.0000036561.60552.63] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present study determined whether gene transfer of human copper/zinc superoxide dismutase-1 (Cu/Zn SOD-1) prevented the autoregulatory impairment of CBF induced by subarachnoid hemorrhage (SAH). After application of recombinant adenovirus (100 microL of 1 x 10(10) pfu/mL, intracisternally) encoding human Cu/Zn SOD-1 3 days before experiments, Cu/Zn SOD-1 activity significantly increased in association with increase in Cu/Zn SOD-1 mRNA and protein expression in the cerebral vasculature of both sham-operated and SAH rats as determined by reverse transcriptase-polymerase chain reaction, Western blotting, and immunohistochemistry, and SAH-induced increase in superoxide anion was markedly reduced in accordance with increased nitric oxide production. In line with these findings, rats that received human Cu/Zn SOD-1 therapy showed the prominent restoration of blunted vasodilation of the pial artery in response to calcitonin gene-related peptide and levcromakalim, and the recovery of impaired autoregulatory vasodilation in response to acute hypotension, thereby leading to significant restoration of CBF autoregulation. These results provide a rational basis for application of Cu/Zn SOD-1 gene therapy for protection of the impairment of autoregulatory CBF during the acute stage of SAH.
Collapse
Affiliation(s)
- Hwa Kyoung Shin
- Department of Pharmacology and Internal Medicine, College of Medicine, Research Institute of Genetic Engineering, Pusan National University, Seo-Gu, Busan, South Korea
| | | | | | | | | | | |
Collapse
|
47
|
On YK, Kim HS, Kim SY, Chae IH, Oh BH, Lee MM, Park YB, Choi YS, Chung MH. Vitamin C prevents radiation-induced endothelium-dependent vasomotor dysfunction and de-endothelialization by inhibiting oxidative damage in the rat. Clin Exp Pharmacol Physiol 2001; 28:816-21. [PMID: 11553021 DOI: 10.1046/j.1440-1681.2001.03528.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. The present study was undertaken to determine whether endothelial function or morphology was altered in aortic rings of rats after irradiation, to investigate the mechanism of radiation effects on the endothelium and to examine the effect of vitamin C treatment against radiation-induced damage of the endothelium. 2. Female Sprague-Dawley rats were randomized into four groups (control, radiation, radiation + vitamin C, radiation + vitamin C + NG-nitro-L-arginine methyl ester (L-NAME); n = 10 for each group and n = 7 for the control group) and were irradiated with 10 Gy of 137Cs as a radiation source. Segments of the thoracic aorta were obtained and isometric tension, levels of 8-hydroxydeoxyguanosine (OH-dG) and immunohistochemical staining were measured. 3. Irradiation significantly impaired the acetylcholine-induced vasodilation of aortic segments, an effect that could be prevented by pretreatment with vitamin C (500 mg/kg per day). This beneficial effect of vitamin C was abolished by the addition of L-NAME (100 microg/kg per day), an inhibitor of nitric oxide (NO) synthesis. Irradiation significantly increased the level of OH-dG in the aorta (1.02 +/- 0.27 vs 2.61 +/- 0.78 OH-dG/105 deoxyguanosine (dG) for control and irradiated tissues, respectively; P < 0.01), an increase that was prevented by vitamin C treatment (1.59 +/- 0.23 OH-dG/105 dG; P < 0.01). Irradiation caused significant de-endothelialization (von Willebrand factor (vWF) staining was 93 +/- 7 vs 100% in irradiated and control tissues, respectively; P < 0.05) and this was prevented by vitamin C treatment (vWF staining 98 +/- 3%; P < 0.05). 4. Radiation caused endothelial damage and impaired NO production through oxidative injury, resulting in a selective impairment of endothelial-dependent vasodilation that could be prevented by vitamin C, partly through anti-oxidant mechanisms.
Collapse
Affiliation(s)
- Y K On
- Cardiovascular Laboratory, Clinical Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Didion SP, Hathaway CA, Faraci FM. Superoxide levels and function of cerebral blood vessels after inhibition of CuZn-SOD. Am J Physiol Heart Circ Physiol 2001; 281:H1697-703. [PMID: 11557560 DOI: 10.1152/ajpheart.2001.281.4.h1697] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The goal of this study was to examine the role of endogenous copper/zinc (CuZn)-superoxide dismutase (SOD) on superoxide levels and on responses of cerebral blood vessels to stimuli that are mediated by nitric oxide (acetylcholine) and cyclooxygenase-dependent mechanisms (bradykinin and arachidonic acid). Levels of superoxide in the rabbit basilar artery were measured using lucigenin-enhanced chemiluminescence (5 microM lucigenin). Diethyldithiocarbamate (DDC; 10 mM), an inhibitor of CuZn-SOD, increased superoxide levels by approximately 2.4-fold (P < 0.05) from a baseline value of 1.0 +/- 0.2 relative light units x min(-1) x mm(-2) (means +/- SE). The diameter of cerebral arterioles (baseline diameter, 99 +/- 3 microm) was also measured using a closed cranial window in anesthetized rabbits. Topical application of DDC attenuated responses to acetylcholine, bradykinin, and arachidonate, but not nitroprusside. For example, 10 microM arachidonic acid dilated cerebral arterioles by 40 +/- 5 and 2 +/- 2 microm under control conditions and after DDC, respectively (P < 0.05). These inhibitory effects of DDC were reversed by the superoxide scavenger 4,5-dihydroxy-1,3-benzenedisulfonic acid (10 mM). Arachidonate increased superoxide levels in the basilar artery moderately under normal conditions and this increase was greatly augmented in the presence of DDC. These findings suggest that endogenous CuZn-SOD limits superoxide levels under basal conditions and has a marked influence on increases in superoxide in vessels exposed to arachidonic acid. The results also suggest that nitric oxide- and cyclooxygenase-mediated responses in the cerebral microcirculation are dependent on normal activity of CuZn-SOD.
Collapse
Affiliation(s)
- S P Didion
- Department of Internal Medicine, Cardiovascular Center, University of Iowa College of Medicine, Iowa City, Iowa 52242-1081, USA
| | | | | |
Collapse
|
49
|
Armstead WM. Endothelin-Induced cyclooxygenase-dependent superoxide generation contributes to K+ channel functional impairment after brain injury. J Neurotrauma 2001; 18:1039-48. [PMID: 11686491 DOI: 10.1089/08977150152693737] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study determined if endothelin (ET-1) generates superoxide anion (O2-) in a cyclooxygenase-dependent manner and if such production contributes to impairment of dilation to activators of ATP-sensitive K+ (KATP) and calcium-sensitive K+ (Kca) channels following fluid percussion brain injury (FPI) in newborn pigs equipped with closed cranial windows. Superoxide dismutase (SOD)-inhibitable nitroblue tetrazolium (NBT) reduction was determined as an index of O2- generation. Under non-brain injury conditions, topical ET-1 (10(-10) M, the concentration present in CSF following FPI) increased SOD-inhibitable NBT reduction from 1 +/- 1 to 17 +/- 3 pmol/mm2. Indomethacin, a cyclooxygenase inhibitor, blunted such NBT reduction (1 +/- 1 to 4 +/- 1 pmol/mm2), while the ET-1 antagonist BQ123 blocked NBT reduction. BQ123 and indomethacin also blunted the NBT reduction observed after FPI. Under non-brain injury conditions, ET-1 (10(-10) M) coadministered with the KATP and Kca channel agonists cromakalim and NS1619 (10-8, 10(-6) M) diminished dilation to these K+ channel agonists, while indomethacin partially prevented such impairment (13 +/- 1 and 23 +/- 1 vs. 2 +/- 1 and 6 +/- 1 vs. 6 +/- 1 and 14 +/- 2% for cromakalim in untreated, ET-1, and ET-1 plus indomethacin-treated piglets, respectively). Cromakalim- and NS1619-induced pial artery dilation was attenuated following FPI, while indomethacin or BQ123 preadministration partially prevented such impairment (13 +/- 1 and 23 +/- 1, sham control; 1 +/- 1 and 4 +/- 1, FPI; 8 +/- 1 and 16 +/- 3%, FPI and indomethacin-pretreated for responses to cromakalim 10(-8), 10-6 M, respectively). These data show that ET-1 increased O2- production in a cyclooxygenase-dependent manner and contributed to this production after FPI. These data also show that ET-1 blunted KATP and Kca channel-mediated cerebrovasodilation in a cyclooxygenase dependent manner. These data suggest that ET-1-induced cyclooxygenase-dependent O2- generation contributes to KATP and Kca channel function impairment after FPI.
Collapse
Affiliation(s)
- W M Armstead
- Department of Anesthesia, University of Pennsylvania, Philadelphia 19104, USA.
| |
Collapse
|
50
|
Lee JY, Bae ON, Chung SM, Lee MY, Chung JH. Menadione induces endothelial dysfunction mediated by oxidative stress and arylation. Chem Biol Interact 2001; 137:169-83. [PMID: 11551532 DOI: 10.1016/s0009-2797(01)00235-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Our previous studies showed that menadione causes endothelial dysfunction which results in decreased relaxation and increased contraction of blood vessels. This investigation examined the role of two possible mechanisms (oxidative stress and arylation) in menadione-induced endothelial dysfunction. Menadione increased superoxide anion generation in aortic rings in a dose-dependent manner. Superoxide dismutase (SOD), reversed the inhibitory effects of menadione on vascular relaxation. The relaxation induced by the NO donor, sodium nitroprusside, was inhibited by menadione pretreatment in a dose-dependent manner. Endothelial nitric oxide synthase activity (eNOS) was suppressed by menadione. Menadione resulted in a dose-dependent reduction of cGMP levels accumulated by acetylcholine. This reduction of cGMP levels was blocked by SOD treatment, suggesting that superoxide anion generated by menadione could play a role in the inhibition of the nitric oxide pathway. Evidence supporting a possible role for arylation in impaired vascular relaxation was suggested by the observation that benzoquinone, which does not induce oxidative stress in aortic rings, inhibited acetylcholine-induced vascular relaxation to the same extent as menadione. Collectively, these results suggest that menadione can cause endothelial dysfunction in blood vessels by the inhibition of the nitric oxide pathway via superoxide anion generation and that arylation activity may also be another important mechanism.
Collapse
Affiliation(s)
- J Y Lee
- College of Pharmacy, Seoul National University, Shinrim-dong San 56-1, 151-742, Seoul, South Korea
| | | | | | | | | |
Collapse
|