1
|
Syed AA, Shafiq M, Reza MI, Bharati P, Husain A, Singh P, Hanif K, Gayen JR. Ethanolic extract of Cissus quadrangularis improves vasoreactivity by modulation of eNOS expression and oxidative stress in spontaneously hypertensive rats. Clin Exp Hypertens 2021; 44:63-71. [PMID: 34648416 DOI: 10.1080/10641963.2021.1991942] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Endothelial dysfunction is related to the reduced bioavailability of nitric oxide (NO) and plays a significant role in developing hypertension. The intake of a diet rich in antioxidants decreases the threat of hypertension. Cissus quadrangularis possesses antioxidant, anti-inflammatory, and hypocholesterolemic activities. However, to date, no studies have been performed to explore this plant's antihypertensive and vasorelaxant activity. Herein, we investigated the chronic effect of C. quadrangularis on blood pressure as well as vascular function in hypertensive rats. METHODS Male spontaneously hypertensive rats (SHR) were randomly divided into two groups. Normotensive Wistar rats were taken as the control group. The treatment was done using ethanolic extract of C. quadrangularis (EECQ) at a dose of 200 mg/kg. RESULTS The administration of EECQ for six weeks reduced the systolic blood pressure, mean arterial blood pressure, and heart rate. It also alleviated the cardiac and renal hypertrophy indices. Supplementation of EECQ improved the endothelium-dependent aortic vasodilation induced by acetylcholine. It restored the NO level and endothelial NO synthase expression in the aorta. Subsequently, the extract alleviates the oxidative stress and inflammatory markers in SHR rats. CONCLUSION Thus, in the present study, the chronic treatment of EECQ to genetically hypertensive rats improved endothelium-dependent relaxation in addition to its antihypertensive effect by eNOS activation and inhibition of ROS production, inflammation.
Collapse
Affiliation(s)
- Anees Ahmed Syed
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research (Acsir), Ghaziabad, India
| | - Mohammed Shafiq
- Academy of Scientific and Innovative Research (Acsir), Ghaziabad, India.,Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Mohammad Irshad Reza
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Pragya Bharati
- Academy of Scientific and Innovative Research (Acsir), Ghaziabad, India.,Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Athar Husain
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research (Acsir), Ghaziabad, India
| | - Pragati Singh
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Kashif Hanif
- Academy of Scientific and Innovative Research (Acsir), Ghaziabad, India.,Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Jiaur R Gayen
- Pharmaceutics & Pharmacokinetics Division, CSIR-Central Drug Research Institute, Lucknow, India.,Academy of Scientific and Innovative Research (Acsir), Ghaziabad, India.,Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow, India
| |
Collapse
|
2
|
Luttrell M, Kim H, Shin SY, Holly D, Massett MP, Woodman CR. Heterogeneous effect of aging on vasorelaxation responses in large and small arteries. Physiol Rep 2020; 8:e14341. [PMID: 31960593 PMCID: PMC6971410 DOI: 10.14814/phy2.14341] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aging is associated with impaired vascular function characterized in part by attenuated vasorelaxation to acetylcholine (ACh) and sodium nitroprusside (SNP). Due to structural and functional differences between conduit and resistance arteries, the effect of aging on vasorelaxation responses may vary along the arterial tree. Our purpose was to determine age-related differences in vasorelaxation responses in large and small arteries. Responses to the endothelium-dependent vasodilator acetylcholine (ACh) and the endothelium-independent vasodilator sodium nitroprusside (SNP) were assessed in abdominal aorta (AA), iliac arteries (IA), femoral arteries (FA), and gastrocnemius feed arteries (GFA) from young and old male rats. ACh-mediated vasorelaxation was significantly impaired in old AA and IA. SNP-mediated vasorelaxation was impaired in old AA. To investigate a potential mechanism for impaired relaxation responses in AA and IA, we assessed eNOS protein content and interactions with caveolin-1 (Cav-1), and calmodulin (CaM) via immunoprecipitation and immunoblot analysis. We found no age differences in eNOS content or interactions with Cav1 and CaM. Combined data from all rats revealed that eNOS content was higher in IA compared to AA and FA (p < .001), and was higher in GFA than AA (p < .05). Cav1:eNOS interaction was greater in FA than in AA and IA (p < .01), and in GFA compared to IA (p < .05). No differences in CaM:eNOS were detected. In conclusion, age-related impairment of vasorelaxation responses occurred in the large conduit, but not small conduit or resistance arteries. These detrimental effects of age were not associated with changes in eNOS or its interactions with Cav-1 or CaM.
Collapse
Affiliation(s)
- Meredith Luttrell
- Department of Health & KinesiologyTexas A&M UniversityCollege StationTexas
| | - Hyoseon Kim
- Department of Health & KinesiologyTexas A&M UniversityCollege StationTexas
- Present address:
Department of Kinesiology and Sport ManagementTexas Tech UniversityLubbockTexas
| | - Song Yi Shin
- Department of Health & KinesiologyTexas A&M UniversityCollege StationTexas
| | - Dylan Holly
- Department of Health & KinesiologyTexas A&M UniversityCollege StationTexas
| | - Michael P. Massett
- Department of Health & KinesiologyTexas A&M UniversityCollege StationTexas
- Present address:
Department of Kinesiology and Sport ManagementTexas Tech UniversityLubbockTexas
| | - Christopher R. Woodman
- Department of Health & KinesiologyTexas A&M UniversityCollege StationTexas
- Department of Veterinary Physiology & PharmacologyTexas A&M UniversityCollege StationTexas
| |
Collapse
|
3
|
Effect of N-Acetyl Cysteine on Intracerebroventricular Colchicine Induced Cognitive Deficits, Beta Amyloid Pathology, and Glial Cells. NEUROSCIENCE JOURNAL 2019; 2019:7547382. [PMID: 31139638 PMCID: PMC6500609 DOI: 10.1155/2019/7547382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 03/20/2019] [Indexed: 01/01/2023]
Abstract
Among the many factors responsible for the cognitive decline in Alzheimer's disease, beta amyloid protein and plaque formation is crucial. This amyloid pathology is associated with activation of glial cells and oxidative stress but whether oxidative stress activates beta amyloid protein in the neurons is not clear. Further the expression of microglia is also known to vary during pathogenesis of beta amyloid plaques. The aim of the present study is to evaluate the antioxidant effect of NAC on amyloid pathology and cognition and also to investigate the link between amyloid pathology and glial cells activation. Intracerebroventricular colchicine in rats known mimics human AD in many aspects including memory loss, oxidative stress, and hyper phosphorylation of tau protein. The animal groups consisted of age matched control, sham operated, AD, and NAC treated in AD models of rats. Cognitive function was evaluated in active avoidance test; beta amyloid protein, beta amyloid plaques, astrocytes, and microglia cells were quantified using immunohistochemistry in hippocampal and prefrontal cortices. Colchicine has resulted in significant cognitive loss, increased intraneuronal beta amyloid protein expression, increased reactive astrocytes, and activated microglia in all the regions of the hippocampus and prefrontal cortices. The antioxidant NAC has reversed the cognitive deficits and inhibited microglia activation but failed to inhibit BAP expression and astrocytosis. Intraneuronal BAP accumulation is deleterious and known to adversely affect cognition, but in this study in spite of intraneuronal BAP accumulation, the cognition is restored. It can be postulated that NAC might have reversed the effect of intraneuronal beta amyloid protein by acting on some downstream compensatory mechanisms which needs to be explored.
Collapse
|
4
|
Alehagen U, Johansson P, Aaseth J, Alexander J, Brismar K. Increase in insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 after supplementation with selenium and coenzyme Q10. A prospective randomized double-blind placebo-controlled trial among elderly Swedish citizens. PLoS One 2017; 12:e0178614. [PMID: 28609475 PMCID: PMC5469470 DOI: 10.1371/journal.pone.0178614] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 05/14/2017] [Indexed: 12/11/2022] Open
Abstract
Background Insulin-like growth factor-1(IGF-1) has a multitude of effects besides cell growth and metabolism. Reports also indicate anti-inflammatory and antioxidative effects. The concentrations of IGF-1 decrease with age and during inflammation. As selenium and coenzyme Q10 are involved in both the antioxidative defense and the inflammatory response, the present study aimed to examine the effects of supplementation with selenium and coenzyme Q10 on concentrations of IGF-1 and its binding protein IGFBP-1 in a population showing reduced cardiovascular mortality following such supplementation. Methods 215 elderly individuals were included and given the intervention for four years. A clinical examination was performed and blood samples were taken at the start and after 48 months. Evaluations of IGF-1, the age adjusted IGF-1 SD score and IGFBP-1 were performed using group mean values, and repeated measures of variance. Findings After supplementation with selenium and coenzyme Q10, applying group mean evaluations, significantly higher IGF-1 and IGF-1 SD scores could be seen in the active treatment group, whereas a decrease in concentration could be seen of the same biomarkers in the placebo group. Applying the repeated measures of variance evaluations, the same significant increase in concentrations of IGF-1 (F = 68; P>0.0001), IGF-1 SD score (F = 29; P<0.0001) and of IGFBP-1 (F = 6.88; P = 0.009) could be seen, indicating the effect of selenium and coenzyme Q10 also on the expression of IGF-1 as one of the mechanistic effects of the intervention. Conclusion Supplementation with selenium and coenzyme Q10 over four years resulted in increased levels of IGF-1 and the postprandial IGFBP-1, and an increase in the age-corrected IGF-1 SD score, compared with placebo. The effects could be part of the mechanistic explanation behind the surprisingly positive clinical effects on cardiovascular morbidity and mortality reported earlier. However, as the effects of IGF-1 are complex, more research on the result of intervention with selenium and coenzyme Q10 is needed.
Collapse
Affiliation(s)
- Urban Alehagen
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- * E-mail:
| | - Peter Johansson
- Division of Cardiovascular Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
- Department of Social and Welfare Studies, Linköping University, Norrköping, Sweden
| | - Jan Aaseth
- Research Department, Innlandet Hospital Trust, Brumunddal, Norway, and Hedmark University of Applied Sciences, Elverum, Norway
| | - Jan Alexander
- Norwegian Institute of Public Health, Oslo, and Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Kerstin Brismar
- Department of Molecular Medicine and Surgery, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
5
|
Puzserova A, Bernatova I. Blood pressure regulation in stress: focus on nitric oxide-dependent mechanisms. Physiol Res 2017; 65:S309-S342. [PMID: 27775419 DOI: 10.33549/physiolres.933442] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Stress is considered a risk factor associated with the development of various civilization diseases including cardiovascular diseases, malignant tumors and mental disorders. Research investigating mechanisms involved in stress-induced hypertension have attracted much attention of physicians and researchers, however, there are still ambiguous results concerning a causal relationship between stress and long-term elevation of blood pressure (BP). Several studies have observed that mechanisms involved in the development of stress-induced hypertension include increased activity of sympathetic nervous system (SNS), glucocorticoid (GC) overload and altered endothelial function including decreased nitric oxide (NO) bioavailability. Nitric oxide is well known neurotransmitter, neuromodulator and vasodilator involved in regulation of neuroendocrine mechanisms and cardiovascular responses to stressors. Thus NO plays a crucial role in the regulation of the stress systems and thereby in the BP regulation in stress. Elevated NO synthesis, especially in the initial phase of stress, may be considered a stress-limiting mechanism, facilitating the recovery from stress to the resting levels via attenuation of both GC release and SNS activity as well as by increased NO-dependent vasorelaxation. On the other hand, reduced levels of NO were observed in the later phases of stress and in subjects with genetic predisposition to hypertension, irrespectively, in which reduced NO bioavailability may account for disruption of NO-mediated BP regulatory mechanisms and accentuated SNS and GC effects. This review summarizes current knowledge on the role of stress in development of hypertension with a special focus on the interactions among NO and other biological systems affecting blood pressure and vascular function.
Collapse
Affiliation(s)
- A Puzserova
- Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
| | | |
Collapse
|
6
|
Paredes A, Palacios J, Quispe C, Nwokocha CR, Morales G, Kuzmicic J, Cifuentes F. Hydroalcoholic extract and pure compounds from Senecio nutans Sch. Bip (Compositae) induce vasodilation in rat aorta through endothelium-dependent and independent mechanisms. JOURNAL OF ETHNOPHARMACOLOGY 2016; 192:99-107. [PMID: 27392595 DOI: 10.1016/j.jep.2016.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/22/2016] [Accepted: 07/04/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Senecio nutans Sch. Bip. (Compositae) is an endemic plant of South America, and is used in herbal medicine in Andean communities for treating acute mountain sickness. Currently, the direct effects of hydroalcoholic extract of S. nutans (HAE S. nutans) or its isolated compounds on the vascular system are not well described. The aim of this study was to determine the effects and mechanism of action of S. nutans on vascular function in healthy rats. MATERIAL AND METHODS Seven compounds were isolated from the HAE S. nutans, and their structures were characterized using spectroscopic techniques as 1D and 2D NMR, and mass spectrometry. Vascular reactivity experiments were carried out in rat aorta. S. nutans-dependent vasodilation and phenylephrine-dependent contraction were measured in endothelium-intact and endothelium-denuded aortic rings of male rats. RESULTS Seven pure compounds were isolate from HAE S. nutans, but two pure compounds showed significant vasodilation in rat aorta: 4-hydroxy-3-(3-methyl-2-butenyl)acetophenone (compound E) and 5-acetyl-6-hydroxy-2-isopropenyl-2,3-dihydrobenzofurane (compound G). Although HAE S. nutans induced vasodilation in absence of endothelium, the vasodilation in intact aorta, via NO, was higher. HAE S. nutans reduced calcium-dependent contraction in endothelium-intact, but not in endothelium-denuded aortic rings. CONCLUSION HAE S. nutans and its isolated compounds caused vasodilation in rat aorta in absence of endothelium, suggesting its vasodilator properties is endothelium-dependent (NO) and or independent, and may involve a modulation of the calcium channels. This result is of clinical interest as potential therapy control of blood pressure.
Collapse
Affiliation(s)
- Adrián Paredes
- Laboratorio de Química Biológica, Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile
| | - Javier Palacios
- (b)Facultad Ciencias de la Salud, Instituto de EtnoFarmacología (IDE), Universidad Arturo Prat, Iquique, Chile.
| | - Cristina Quispe
- (b)Facultad Ciencias de la Salud, Instituto de EtnoFarmacología (IDE), Universidad Arturo Prat, Iquique, Chile
| | - Chukwuemeka R Nwokocha
- Department of Basic Medical Sciences Physiology Section, Faculty of Medical Sciences, The University of the West Indies, Mona, Kingston 7, Jamaica, W.I
| | - Glauco Morales
- Laboratorio de Química Biológica, Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile
| | - Jovan Kuzmicic
- Laboratorio de Fisiología Experimental (EPhyL), Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile
| | - Fredi Cifuentes
- Laboratorio de Fisiología Experimental (EPhyL), Instituto Antofagasta (IA), Universidad de Antofagasta, Antofagasta, Chile
| |
Collapse
|
7
|
Mitochondrial function in hypoxic ischemic injury and influence of aging. Prog Neurobiol 2016; 157:92-116. [PMID: 27321753 DOI: 10.1016/j.pneurobio.2016.06.006] [Citation(s) in RCA: 234] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 03/30/2016] [Accepted: 06/12/2016] [Indexed: 12/11/2022]
Abstract
Mitochondria are a major target in hypoxic/ischemic injury. Mitochondrial impairment increases with age leading to dysregulation of molecular pathways linked to mitochondria. The perturbation of mitochondrial homeostasis and cellular energetics worsens outcome following hypoxic-ischemic insults in elderly individuals. In response to acute injury conditions, cellular machinery relies on rapid adaptations by modulating posttranslational modifications. Therefore, post-translational regulation of molecular mediators such as hypoxia-inducible factor 1α (HIF-1α), peroxisome proliferator-activated receptor γ coactivator α (PGC-1α), c-MYC, SIRT1 and AMPK play a critical role in the control of the glycolytic-mitochondrial energy axis in response to hypoxic-ischemic conditions. The deficiency of oxygen and nutrients leads to decreased energetic reliance on mitochondria, promoting glycolysis. The combination of pseudohypoxia, declining autophagy, and dysregulation of stress responses with aging adds to impaired host response to hypoxic-ischemic injury. Furthermore, intermitochondrial signal propagation and tissue wide oscillations in mitochondrial metabolism in response to oxidative stress are emerging as vital to cellular energetics. Recently reported intercellular transport of mitochondria through tunneling nanotubes also play a role in the response to and treatments for ischemic injury. In this review we attempt to provide an overview of some of the molecular mechanisms and potential therapies involved in the alteration of cellular energetics with aging and injury with a neurobiological perspective.
Collapse
|
8
|
Phosphodiesterase 1 regulation is a key mechanism in vascular aging. Clin Sci (Lond) 2015; 129:1061-75. [PMID: 26464516 DOI: 10.1042/cs20140753] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 06/25/2015] [Indexed: 12/31/2022]
Abstract
Reduced nitric oxide (NO)/cGMP signalling is observed in age-related vascular disease. We hypothesize that this disturbed signalling involves effects of genomic instability, a primary causal factor in aging, on vascular smooth muscle cells (VSMCs) and that the underlying mechanism plays a role in human age-related vascular disease. To test our hypothesis, we combined experiments in mice with genomic instability resulting from the defective nucleotide excision repair gene ERCC1 (Ercc1(d/-) mice), human VSMC cultures and population genome-wide association studies (GWAS). Aortic rings of Ercc1(d/-) mice showed 43% reduced responses to the soluble guanylate cyclase (sGC) stimulator sodium nitroprusside (SNP). Inhibition of phosphodiesterase (PDE) 1 and 5 normalized SNP-relaxing effects in Ercc1(d/-) to wild-type (WT) levels. PDE1C levels were increased in lung and aorta. cGMP hydrolysis by PDE in lungs was higher in Ercc1(d/-) mice. No differences in activity or levels of cGMP-dependent protein kinase 1 or sGC were observed in Ercc1(d/-) mice compared with WT. Senescent human VSMC showed elevated PDE1A and PDE1C and PDE5 mRNA levels (11.6-, 9- and 2.3-fold respectively), which associated with markers of cellular senescence. Conversely, PDE1 inhibition lowered expression of these markers. Human genetic studies revealed significant associations of PDE1A single nucleotide polymorphisms with diastolic blood pressure (DBP; β=0.28, P=2.47×10(-5)) and carotid intima-media thickness (cIMT; β=-0.0061, P=2.89×10(-5)). In summary, these results show that genomic instability and cellular senescence in VSMCs increase PDE1 expression. This might play a role in aging-related loss of vasodilator function, VSMC senescence, increased blood pressure and vascular hypertrophy.
Collapse
|
9
|
Retarding the senescence of human vascular endothelial cells induced by hydrogen peroxide: effects of 17beta-estradiol (E2) mediated mitochondria protection. Biogerontology 2014; 15:367-75. [DOI: 10.1007/s10522-014-9507-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 05/30/2014] [Indexed: 01/26/2023]
|
10
|
Higashi Y, Quevedo HC, Tiwari S, Sukhanov S, Shai SY, Anwar A, Delafontaine P. Interaction between insulin-like growth factor-1 and atherosclerosis and vascular aging. FRONTIERS OF HORMONE RESEARCH 2014; 43:107-24. [PMID: 24943302 DOI: 10.1159/000360571] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The process of vascular aging encompasses alterations in the function of endothelial (ECs) and vascular smooth muscle cells (VSMCs) via oxidation, inflammation, cell senescence and epigenetic modifications, increasing the probability of atherosclerosis. Aged vessels exhibit decreased endothelial antithrombogenic properties, increased reactive oxygen species generation, inflammatory signaling and migration of VSMCs to the subintimal space, impaired angiogenesis and increased elastin degradation. The key initiating step in atherogenesis is subendothelial accumulation of apolipoprotein B-containing low-density lipoproteins resulting in activation of ECs and recruitment of monocytes. Activated ECs secrete 'chemokines' that interact with cognate chemokine receptors on monocytes and promote directional migration. Recruitment of immune cells establishes a proinflammatory status, further causing elevated oxidative stress, which in turn triggers a series of events including apoptotic or necrotic death of vascular and nonvascular cells. Increased oxidative stress is also considered to be a key factor in mechanisms of aging-associated changes in tissue integrity and function. Experimental evidence indicates that insulin-like growth factor-1 exerts antioxidant, anti-inflammatory and pro-survival effects on the vasculature, reducing atherosclerotic plaque burden and promoting features of atherosclerotic plaque stability.
Collapse
Affiliation(s)
- Yusuke Higashi
- Tulane University School of Medicine, Tulane University Heart and Vascular Institute, New Orleans, La., USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Time-related alteration in flow- (shear stress-) mediated remodeling in resistance arteries from spontaneously hypertensive rats. Int J Hypertens 2014; 2014:859793. [PMID: 24900916 PMCID: PMC4034663 DOI: 10.1155/2014/859793] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/31/2014] [Accepted: 03/31/2014] [Indexed: 11/17/2022] Open
Abstract
Hypertension is a major risk factor for cardiovascular disorders. As flow-mediated outward remodeling has a key role in postischemic revascularization, we investigated this remodeling in mesenteric resistance arteries of normotensive (WKY) and spontaneously hypertensive rats (SHRs) aged 3 to 9 months. Sequential ligation of mesenteric resistance arteries allowed modifying blood flow in vivo, thus exposing arteries to low, normal, or high flow. After 1, 3, 8, or 24 weeks, arteries were isolated for in vitro study. High flow (HF) induced outward hypertrophic remodeling in WKY rats after 1 week and persisted until 24 weeks without change in wall to lumen ratio. In SHRs, diameter increase was delayed, occurring only after 3 weeks. Nevertheless, it was reduced at 8 weeks and no longer significant after 24 weeks. In parallel, media cross-section area increased more with time in SHRs than in WKY rats and this was associated with increased contractility and oxidative stress with decreased NO-dependent relaxation. Low flow induced progressive inward remodeling until 24 weeks in both strains with excessive hypertrophy in SHRs. Thus, a chronic increase in flow induced transitory diameter expansion and long-lasting hypertrophy in SHRs. This could contribute to the higher susceptibility of hypertensive subjects to ischemic diseases.
Collapse
|
12
|
Rogers NM, Yao M, Novelli EM, Thomson AW, Roberts DD, Isenberg JS. Activated CD47 regulates multiple vascular and stress responses: implications for acute kidney injury and its management. Am J Physiol Renal Physiol 2012; 303:F1117-25. [PMID: 22874763 PMCID: PMC3469673 DOI: 10.1152/ajprenal.00359.2012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/05/2012] [Indexed: 02/08/2023] Open
Abstract
Ischemia-reperfusion injury (IRI) remains a significant source of early and delayed renal transplant failure. Therapeutic interventions have yet to resolve this ongoing clinical challenge although the reasons for this remain unclear. The cell surface receptor CD47 is widely expressed on vascular cells and in tissues. It has one known soluble ligand, the stress-released matricellular protein thrombospondin-1 (TSP1). The TSP1-CD47 ligand receptor axis controls a number of important cellular processes, inhibiting survival factors such as nitric oxide, cGMP, cAMP, and VEGF, while activating injurious pathways such as production of reactive oxygen species. A role of CD47 in renal IRI was recently revealed by the finding that the TSP1-CD47 axis is induced in renal tubular epithelial cells (RTEC) under hypoxia and following IRI. The absence of CD47 in knockout mice increases survival, mitigates RTEC damage, and prevents subsequent kidney failure. Conversely, therapeutic blockade of TSP1-CD47 signaling provides these same advantages to wild-type animals. Together, these findings suggest an important role for CD47 in renal IRI as a proximate promoter of injury and as a novel therapeutic target.
Collapse
Affiliation(s)
- Natasha M Rogers
- Vascular Medicine Institute, University of Pittsburgh School of Medicine, 200 Lothrop St., Pittsburgh, PA 15261, USA
| | | | | | | | | | | |
Collapse
|
13
|
Higashi Y, Sukhanov S, Anwar A, Shai SY, Delafontaine P. Aging, atherosclerosis, and IGF-1. J Gerontol A Biol Sci Med Sci 2012; 67:626-39. [PMID: 22491965 PMCID: PMC3348497 DOI: 10.1093/gerona/gls102] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 03/01/2012] [Indexed: 12/18/2022] Open
Abstract
Insulin-like growth factor 1 (IGF-1) is an endocrine and autocrine/paracrine growth factor that circulates at high levels in the plasma and is expressed in most cell types. IGF-1 has major effects on development, cell growth and differentiation, and tissue repair. Recent evidence indicates that IGF-1 reduces atherosclerosis burden and improves features of atherosclerotic plaque stability in animal models. Potential mechanisms for this atheroprotective effect include IGF-1-induced reduction in oxidative stress, cell apoptosis, proinflammatory signaling, and endothelial dysfunction. Aging is associated with increased vascular oxidative stress and vascular disease, suggesting that IGF-1 may exert salutary effects on vascular aging processes. In this review, we will provide a comprehensive update on IGF-1's ability to modulate vascular oxidative stress and to limit atherogenesis and the vascular complications of aging.
Collapse
Affiliation(s)
- Yusuke Higashi
- Tulane University Heart & Vascular Institute, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
| | | | | | | | | |
Collapse
|
14
|
Zhu Y, Xia M, Yang Y, Liu F, Li Z, Hao Y, Mi M, Jin T, Ling W. Purified anthocyanin supplementation improves endothelial function via NO-cGMP activation in hypercholesterolemic individuals. Clin Chem 2011; 57:1524-33. [PMID: 21926181 DOI: 10.1373/clinchem.2011.167361] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Anthocyanins have been shown to improve endothelial function in animal models. However, whether these compounds have similar beneficial effects in humans is largely unknown. METHODS In a short-term crossover study, 12 hypercholesterolemic individuals were given oral anthocyanins (320 mg) isolated from berries or placebo. Brachial artery flow-mediated dilation (FMD) was assessed before and after the intervention. In a long-term intervention trial (12 weeks), 150 hypercholesterolemic individuals were given anthocyanins (320 mg/day, n = 75) or placebo (n = 75), after which we measured FMD, plasma cGMP, and other serum biomarkers. Another short-term intervention was conducted in the presence of NO-cGMP inhibitors in 6 people and in a rat aortic ring model (n = 8). RESULTS Significant increases of FMD from 8.3% (0.6%) at baseline to 11.0% (0.8%) at 1 h and 10.1% (0.9%) at 2 h were observed after short-term anthocyanin consumption, concomitantly with increases of plasma anthocyanin concentrations (P < 0.05). In the study participants who received long-term anthocyanin intervention, compared with the control group, we observed significant increases in the FMD (28.4% vs 2.2%), cGMP (12.6% vs -1.2%), and HDL-cholesterol concentrations, but decreases in the serum soluble vascular adhesion molecule-1 and LDL cholesterol concentrations (P < 0.05). The changes in the cGMP and HDL cholesterol concentrations positively correlated with FMD in the anthocyanin group (P < 0.05). In the presence of NO-cGMP inhibitors, the effects of anthocyanin on endothelial function were abolished in human participants and in a rat aortic ring model. CONCLUSIONS Anthocyanin supplementation improves endothelium-dependent vasodilation in hypercholesterolemic individuals. This effect involves activation of the NO-cGMP signaling pathway, improvements in the serum lipid profile, and decreased inflammation.
Collapse
Affiliation(s)
- Yanna Zhu
- Guangdong Provincial Key Laboratory of Food, Nutrition, and Health, School of Public Health,SunYat-Sen University (Northern Campus), Guangzhou, China
| | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Bessa KL, Belletati JF, Santos L, Rossoni LV, Ortiz JP. Drag reduction by polyethylene glycol in the tail arterial bed of normotensive and hypertensive rats. Braz J Med Biol Res 2011; 44:767-77. [PMID: 21670893 DOI: 10.1590/s0100-879x2011007500071] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Accepted: 05/26/2011] [Indexed: 11/21/2022] Open
Abstract
This study was designed to evaluate the effect of drag reducer polymers (DRP) on arteries from normotensive (Wistar) and spontaneously hypertensive rats (SHR). Polyethylene glycol (PEG 4000 at 5000 ppm) was perfused in the tail arterial bed with (E+) and without endothelium (E-) from male, adult Wistar (N = 14) and SHR (N = 13) animals under basal conditions (constant flow at 2.5 mL/min). In these preparations, flow-pressure curves (1.5 to 10 mL/min) were constructed before and 1 h after PEG 4000 perfusion. Afterwards, the tail arterial bed was fixed and the internal diameters of the arteries were then measured by microscopy and drag reduction was assessed based on the values of wall shear stress (WSS) by computational simulation. In Wistar and SHR groups, perfusion of PEG 4000 significantly reduced pulsatile pressure (Wistar/E+: 17.5 ± 2.8; SHR/E+: 16.3 ± 2.7%), WSS (Wistar/E+: 36; SHR/E+: 40%) and the flow-pressure response. The E- reduced the effects of PEG 4000 on arteries from both groups, suggesting that endothelial damage decreased the effect of PEG 4000 as a DRP. Moreover, the effects of PEG 4000 were more pronounced in the tail arterial bed from SHR compared to Wistar rats. In conclusion, these data demonstrated for the first time that PEG 4000 was more effective in reducing the pressure-flow response as well as WSS in the tail arterial bed of hypertensive than of normotensive rats and these effects were amplified by, but not dependent on, endothelial integrity. Thus, these results show an additional mechanism of action of this polymer besides its mechanical effect through the release and/or bioavailability of endothelial factors.
Collapse
Affiliation(s)
- K L Bessa
- Departamento de Ciências Ambientais e Tecnológicas, Universidade Federal Rural do Semi-Árido, Mossoró, RN, Brasil
| | | | | | | | | |
Collapse
|
16
|
Stauss HM, Rarick KR, Leick KM, Burkle JW, Rotella DL, Anderson MG. Noninvasive assessment of vascular structure and function in conscious rats based on in vivo imaging of the albino iris. Am J Physiol Regul Integr Comp Physiol 2011; 300:R1333-43. [PMID: 21389331 DOI: 10.1152/ajpregu.00561.2010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experimental techniques allowing longitudinal studies of vascular disease progression or treatment effects are not readily available for most animal models. Thus, most existing studies are destined to either study individual time points or use large cohorts of animals. Here we describe a noninvasive technique for studying vascular disease that is based on in vivo imaging of the long posterior ciliary artery (LPCA) in the iris of albino rats. Using a slit-lamp biomicroscope, images of the LPCA were taken weekly in conscious normotensive Wistar Kyoto rats (WKY, n = 10) and spontaneously hypertensive rats (SHR, n = 10) for 10 wk. Using imaging software, we found that lumen diameter was significantly smaller and the wall-to-lumen (W/L) ratio larger in SHR than in WKY. Wall thickness was not different. Blood pressure correlated with the W/L ratio. Histology of the abdominal aorta also revealed a smaller lumen diameter and greater W/L ratio in SHR compared with WKY. Corneal application of the muscarinic receptor agonist pilocarpine elicited a dose-dependent vasodilation of the LPCA that could be antagonized by inhibition of nitric oxide synthase, suggesting that the pilocarpine response is mainly mediated by endothelium-derived nitric oxide. Consistent with endothelial dysfunction in SHR, pilocarpine-induced vasodilation was greater in WKY rats than in SHR. These findings indicate that in vivo imaging of the LPCA allows assessment of several structural and functional vascular parameters in conscious rats and that the LPCA responds to disease insults and pharmacologic treatments in a fashion that will make it a useful model for further studies.
Collapse
Affiliation(s)
- Harald M Stauss
- Department of Health and Human Physiology, The University of Iowa, Iowa City, 52242, USA.
| | | | | | | | | | | |
Collapse
|
17
|
Perinatal l-arginine and antioxidant supplements reduce adult blood pressure but not ameliorate the altered vascular function in spontaneously hypertensive rats. J Physiol Biochem 2010; 66:301-9. [DOI: 10.1007/s13105-010-0036-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Accepted: 07/15/2010] [Indexed: 01/23/2023]
|
18
|
Abstract
Despite the apparent consensus on the existence of endothelial dysfunction in conduit and resistance arteries of spontaneously hypertensive rats (SHR), a commonly employed experimental model of hypertension, there are a number of reports showing that endothelium-dependent vasodilatory responses are similar, or even increased, in SHR compared with their normotensive counterparts. The present paper aims to discuss the rationale for these apparent discrepancies, including the effect of age, type of artery and methodological aspects. Data from the literature indicate that the age of the animal is a contributing factor and that endothelial dysfunction is likely to be a consequence of hypertension. In addition, the use of antioxidant additives, such as ascorbic acid or ethylene diaminetetraacetic acid, and differences in the level of initial arterial stretch, might also be of importance because they may modify the oxidative status of the artery and the levels of vasoactive factors released by the endothelium.
Collapse
|
19
|
Simonsen U, Christensen FH, Buus NH. The effect of tempol on endothelium-dependent vasodilatation and blood pressure. Pharmacol Ther 2009; 122:109-24. [DOI: 10.1016/j.pharmthera.2009.02.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2009] [Accepted: 02/05/2009] [Indexed: 02/07/2023]
|
20
|
Wilcox CS, Pearlman A. Chemistry and antihypertensive effects of tempol and other nitroxides. Pharmacol Rev 2009; 60:418-69. [PMID: 19112152 DOI: 10.1124/pr.108.000240] [Citation(s) in RCA: 288] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Nitroxides can undergo one- or two-electron reduction reactions to hydroxylamines or oxammonium cations, respectively, which themselves are interconvertible, thereby providing redox metabolic actions. 4-Hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (tempol) is the most extensively studied nitroxide. It is a cell membrane-permeable amphilite that dismutates superoxide catalytically, facilitates hydrogen peroxide metabolism by catalase-like actions, and limits formation of toxic hydroxyl radicals produced by Fenton reactions. It is broadly effective in detoxifying these reactive oxygen species in cell and animal studies. When administered intravenously to hypertensive rodent models, tempol caused rapid and reversible dose-dependent reductions in blood pressure in 22 of 26 studies. This was accompanied by vasodilation, increased nitric oxide activity, reduced sympathetic nervous system activity at central and peripheral sites, and enhanced potassium channel conductance in blood vessels and neurons. When administered orally or by infusion over days or weeks to hypertensive rodent models, it reduced blood pressure in 59 of 68 studies. This was accompanied by correction of salt sensitivity and endothelial dysfunction and reduced agonist-evoked oxidative stress and contractility of blood vessels, reduced renal vascular resistance, and increased renal tissue oxygen tension. Thus, tempol is broadly effective in reducing blood pressure, whether given by acute intravenous injection or by prolonged administration, in a wide range of rodent models of hypertension.
Collapse
Affiliation(s)
- Christopher S Wilcox
- Division of Nephrology and Hypertension, Kidney and Vascular Disorder Center, Georgetown University, Washington, DC 20007, USA.
| | | |
Collapse
|
21
|
Hudes ML, McCann JC, Ames BN. Unusual clustering of coefficients of variation in published articles from a medical biochemistry department in India. FASEB J 2008; 23:689-703. [DOI: 10.1096/fj.08-108910] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mark L. Hudes
- Children's Hospital Oakland Research InstituteOaklandCaliforniaUSA
| | - Joyce C. McCann
- Children's Hospital Oakland Research InstituteOaklandCaliforniaUSA
| | - Bruce N. Ames
- Children's Hospital Oakland Research InstituteOaklandCaliforniaUSA
| |
Collapse
|
22
|
Qiao X, McConnell KR, Khalil RA. Sex steroids and vascular responses in hypertension and aging. ACTA ACUST UNITED AC 2008; 5 Suppl A:S46-64. [PMID: 18395683 DOI: 10.1016/j.genm.2008.03.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2007] [Indexed: 11/26/2022]
Abstract
BACKGROUND Sex hormones play a significant role in human physiology. Estrogen may have protective effects in the cardiovascular system, as evidenced by the decreased incidence of cardiovascular disease (CVD) in premenopausal compared with postmenopausal women. OBJECTIVE This review highlights the acute and long-term effects of sex hormones on the vascular endothelium and vascular smooth muscle (VSM) in adults. Changes in the sex hormone mix, their receptors, and their effects on vascular function in hypertension and aging are also discussed. METHODS Literature collected from the National Centers for Biotechnology Information as identified by a PubMed database search, as well as our experimental work, was used to highlight current knowledge regarding vascular responses to sex hormones in hypertension and in aging. RESULTS Experiments in adult female animals have shown that estrogen induces endothelium-dependent vascular relaxation via the nitric oxide (NO), prostacyclin, and hyperpolarization pathways. Also, surface membrane estrogen receptors (ERs) decrease intracellular free Ca2+ concentration and perhaps protein kinase C-dependent VSM contraction. However, clinical trials such as the Heart and Estrogen/progestin Replacement Study (HERS), HERS-II, and the Women's Health Initiative did not support the experimental findings and demonstrated adverse cardiovascular events of hormone therapy (HT) in aging women. The lack of vascular benefits of HT may be related to the hormone used, the ER, or the patient's cardiovascular condition or age. Experiments on vascular strips from aging (16-month-old) female spontaneously hypertensive rats have shown reduced ER-mediated NO production from endothelial cells and decreased inhibitory effects of estrogen on Ca2+ entry mechanisms of VSM contraction. The age-related decrease in ER-mediated vascular relaxation may explain the decreased effectiveness of HT on CVD in aging women. CONCLUSIONS New HT strategies should further examine the benefits of natural estrogens and phytoestrogens. Transdermal estrogen may be more effective than the oral form, and specific ER modulators may maximize the vascular benefits and reduce the risk of invasive breast cancer. Variants of vascular ERs should be screened for genetic polymorphisms and postmenopausal decrease in the amount of downstream signaling mechanisms. HT may be more effective during the menopausal transition than in late menopause. Progesterone, testosterone, or their specific modulators may be combined with estrogen to provide alternative HT strategies. Thus, HT type, dose, route of administration, and timing should be customized, depending on the patient's cardiovascular condition and age, thereby enhancing the vascular benefits of HT in aging women.
Collapse
Affiliation(s)
- Xiaoying Qiao
- Division of Vascular Surgery, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | | | | |
Collapse
|
23
|
Edwards RL, Lyon T, Litwin SE, Rabovsky A, Symons JD, Jalili T. Quercetin reduces blood pressure in hypertensive subjects. J Nutr 2007; 137:2405-11. [PMID: 17951477 DOI: 10.1093/jn/137.11.2405] [Citation(s) in RCA: 310] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Epidemiological studies report that quercetin, an antioxidant flavonol found in apples, berries, and onions, is associated with reduced risk of coronary heart disease and stroke. Quercetin supplementation also reduces blood pressure in hypertensive rodents. The efficacy of quercetin supplementation to lower blood pressure in hypertensive humans has never been evaluated. We tested the hypothesis that quercetin supplementation reduces blood pressure in hypertensive patients. We then determined whether the antihypertensive effect of quercetin is associated with reductions in systemic oxidant stress. Men and women with prehypertension (n = 19) and stage 1 hypertension (n = 22) were enrolled in a randomized, double-blind, placebo-controlled, crossover study to test the efficacy of 730 mg quercetin/d for 28 d vs. placebo. Blood pressure (mm Hg, systolic/diastolic) at enrollment was 137 +/- 2/86 +/- 1 in prehypertensives and 148 +/- 2/96 +/- 1 in stage 1 hypertensive subjects. Blood pressure was not altered in prehypertensive patients after quercetin supplementation. In contrast, reductions in (P < 0.01) systolic (-7 +/- 2 mm Hg), diastolic (-5 +/- 2 mm Hg), and mean arterial pressures (-5 +/- 2 mm Hg) were observed in stage 1 hypertensive patients after quercetin treatment. However, indices of oxidant stress measured in the plasma and urine were not affected by quercetin. These data are the first to our knowledge to show that quercetin supplementation reduces blood pressure in hypertensive subjects. Contrary to animal-based studies, there was no quercetin-evoked reduction in systemic markers of oxidative stress.
Collapse
Affiliation(s)
- Randi L Edwards
- Division of Nutrition, University of Utah, Salt Lake City, UT 84112, USA
| | | | | | | | | | | |
Collapse
|
24
|
Sena CM, Nunes E, Louro T, Proença T, Fernandes R, Boarder MR, Seiça RM. Effects of alpha-lipoic acid on endothelial function in aged diabetic and high-fat fed rats. Br J Pharmacol 2007; 153:894-906. [PMID: 17906683 PMCID: PMC2267261 DOI: 10.1038/sj.bjp.0707474] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE This study was conducted to investigate the effects of alpha-lipoic acid (alpha-LA) on endothelial function in diabetic and high-fat fed animal models and elucidate the potential mechanism underlying the benefits of alpha-LA. EXPERIMENTAL APPROACH Plasma metabolites reflecting glucose and lipid metabolism, endothelial function, urinary albumin excretion (UAE), plasma and aortic malondialdehyde (MDA) and urinary 8-hydroxydeoxyguanosine (8-OHdG) were assessed in non-diabetic controls (Wistar rats), untreated Goto-Kakizaki (GK) diabetic and high-fat fed GK rats (fed with atherogenic diet only, treated with alpha-LA and treated with vehicle, for 3 months). Vascular eNOS, nitrotyrosine, carbonyl groups and superoxide anion were also assessed in the different groups. KEY RESULTS alpha-LA and soybean oil significantly reduced both total and non-HDL serum cholesterol and triglycerides induced by atherogenic diet. MDA, carbonyl groups, vascular superoxide and 8-OHdG levels were higher in GK and high-fat fed GK groups and fully reversed with alpha-LA treatment. High-fat fed GK diabetic rats showed significantly reduced endothelial function and increased UAE, effects ameliorated with alpha-LA. This endothelial dysfunction was associated with decreased NO production, decreased expression of eNOS and increased vascular superoxide production and nitrotyrosine expression. CONCLUSIONS AND IMPLICATIONS alpha-LA restores endothelial function and significantly improves systemic and local oxidative stress in high-fat fed GK diabetic rats. Improved endothelial function due to alpha-LA was at least partially attributed to recoupling of eNOS and increased NO bioavailability and represents a pharmacological approach to prevent major complications associated with type 2 diabetes.
Collapse
Affiliation(s)
- C M Sena
- Institute of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.
| | | | | | | | | | | | | |
Collapse
|
25
|
Li D, Wang L, Lee CW, Dawson TA, Paterson DJ. Noradrenergic cell specific gene transfer with neuronal nitric oxide synthase reduces cardiac sympathetic neurotransmission in hypertensive rats. Hypertension 2007; 50:69-74. [PMID: 17515453 DOI: 10.1161/hypertensionaha.107.088591] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nitric oxide-cGMP pathway can inhibit cardiac norepinephrine (NE) release. Sympathetic hyper-responsiveness in hypertension may result from oxidative stress impairing this pathway. We tested the hypothesis that the gene transfer of neuronal NO synthase (nNOS) could restore sympathetic balance in the spontaneously hypertensive rat (SHR). An adenovirus (5x10(10) particles) constructed with a noradrenergic neuron-specific promoter (PRS x8) encoding nNOS (Ad.PRS-nNOS) or enhanced green fluorescence protein (Ad.PRS-eGFP) was targeted to the right atrial wall by percutaneous injection in age-matched male SHRs and Wistar-Kyoto (WKY) rats. Five days after transduction, right atria were removed, and evoked [(3)H] norephinephrine (NE) release, NOS activity, and cGMP were measured. In the Ad.PRS-eGFP treated group, tissue levels of cGMP were significantly lower in the SHR compared with the WKY atria. NE release was also greater in the SHR, and soluble guanylate cyclase inhibition did not alter evoked [(3)H] NE release in the Ad.PRS-eGFP-treated SHR. All atria treated with Ad.PRS-nNOS had enhanced nNOS activity when compared with Ad.PRS-eGFP atria. Ad.PRS-nNOS in WKY rats reduced NE release compared with the Ad.PRS-eGFP group. Guanylate cyclase inhibition enhanced NE release in both Ad.PRS-nNOS- and Ad.PRS-eGFP-treated WKY atria. Ad.PRS-nNOS restored cGMP levels in the SHR to those seen in the WKY atria. In the SHR, Ad.PRS-nNOS also attenuated NE release compared with Ad.PRS-eGFP group. This was reversed by guanylate cyclase inhibition. We conclude that artificial upregulation of sympathetic nNOS via gene transfer with a noradrenergic promoter may provide a novel approach for correcting peripheral sympathetic hyperactivity in hypertension.
Collapse
Affiliation(s)
- Dan Li
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy & Genetics, Oxford, UK
| | | | | | | | | |
Collapse
|
26
|
Pechánová O, Zicha J, Paulis L, Zenebe W, Dobesová Z, Kojsová S, Jendeková L, Sládková M, Dovinová I, Simko F, Kunes J. The effect of N-acetylcysteine and melatonin in adult spontaneously hypertensive rats with established hypertension. Eur J Pharmacol 2007; 561:129-36. [PMID: 17321519 DOI: 10.1016/j.ejphar.2007.01.035] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Revised: 01/10/2007] [Accepted: 01/11/2007] [Indexed: 11/21/2022]
Abstract
The attenuated nitric oxide (NO) formation and/or elevated production of reactive oxygen species are often found in experimental and human hypertension. We aimed to determine possible effects of N-acetylcysteine (1.5 g/kg/day) and N-acetyl-5-methoxytryptamine (melatonin, 10 mg/kg/day) in adult spontaneously hypertensive rats (SHR) with established hypertension. After a six-week-treatment, blood pressure was measured and NO synthase (NOS) activity, concentration of conjugated dienes, protein expression of endothelial NOS, inducible NOS and nuclear factor-kappaB (NF-kappaB) in the left ventricle were determined. Both treatments improved the NO pathway by means of enhanced NOS activity and reduced reactive oxygen species level as indicated by decreased conjugated diene concentrations and lowered NF-kappaB expression. N-acetylcysteine (but not melatonin) also increased the endothelial NOS protein expression. However, only melatonin was able to reduce blood pressure significantly. Subsequent in vitro study revealed that both N-acetylcysteine and melatonin lowered the tone of phenylephrine-precontracted femoral artery via NO-dependent relaxation. Nevertheless, melatonin-induced relaxation also involved NO-independent component which was preserved even after the blockade of soluble guanylate cyclase by oxadiazolo[4,3-a]quinoxalin-1-one. In conclusion, both N-acetylcysteine and melatonin were able to improve the NO/reactive oxygen species balance in adult SHR, but blood pressure was significantly lowered by melatonin only. This implies that a partial restoration of NO/reactive oxygen species balance achieved by the antioxidants such as N-acetylcysteine has no therapeutic effect in adult rats with established hypertension. The observed antihypertensive effect of melatonin is thus mediated by additional mechanisms independent of NO pathway.
Collapse
Affiliation(s)
- Olga Pechánová
- Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Bratislava, Slovak Republic.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Rajagopalan S, Kariisa M, Dellegrottaglie S, Bard RL, Kehrer C, Matlow S, Daley W, Pitt B, Brook R. Angiotensin Receptor Blockade Improves Vascular Compliance in Healthy Normotensive Elderly Individuals: Results From a Randomized Double‐Blind Placebo‐Controlled Trial. J Clin Hypertens (Greenwich) 2007; 8:783-90. [PMID: 17086018 PMCID: PMC8109297 DOI: 10.1111/j.1524-6175.2006.05797.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The renin-angiotensin system (RAS) may play a role in vascular aging. The authors hypothesized that blockade of the angiotensin II type 1 receptor with an angiotensin receptor blocker in healthy elderly subjects improves vascular compliance and endothelial function. Thirty-five healthy elderly subjects were randomized to valsartan or placebo in a double-blind crossover study after baseline testing for pulse wave velocity, aortic augmentation index, and brachial artery flow-mediated dilation. Angiotensin II type 1 receptor blockade with valsartan improved vascular compliance but not flow-mediated dilation. Changes in pulse wave velocity with valsartan were correlated with change in central systolic blood pressure and pulse pressure and remained associated on multivariate analysis. Change in pulse wave velocity after adjusting for degree of blood pressure change, age, and sex remained correlated with assignment to the angiotensin receptor blocker but not placebo. These data suggest that angiotensin II type 1 receptor blockade improves aging-related vascular compliance without alterations in flow-mediated dilation. Mechanisms regulating compliance and endothelial function are complex and may not necessarily converge in aging.
Collapse
Affiliation(s)
- Sanjay Rajagopalan
- Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Medical Center, New York, NY, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Jalili T, Carlstrom J, Kim S, Freeman D, Jin H, Wu TC, Litwin SE, David Symons J. Quercetin-supplemented diets lower blood pressure and attenuate cardiac hypertrophy in rats with aortic constriction. J Cardiovasc Pharmacol 2006; 47:531-41. [PMID: 16680066 DOI: 10.1097/01.fjc.0000211746.78454.50] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Quercetin (Q), a flavonoid found in berries and onions, can reduce blood pressure in hypertensive animals and inhibit signal transduction pathways in vitro that regulate cardiac hypertrophy. We hypothesized that quercetin could prevent cardiovascular complications in rats with abdominal aortic constriction (AAC). Rats consumed standard or Q-supplemented chow (1.5 g Q/kg chow) for 7 days before AAC or sham surgery (SHAM, n = 15; AAC, n = 15; SHAMQ, n = 15; AACQ, n = 14). Fourteen days after surgery, plasma and liver Q concentrations were elevated (P < 0.05) and hepatic lipid oxidation was reduced (P < 0.05) in Q-treated versus untreated rats. Carotid arterial blood pressure and cardiac hypertrophy were attenuated (P < 0.05), and cardiac protein kinase C betaII translocation was normalized (P < 0.05) in AACQ versus AAC. Expression of cardiac beta-myosin heavy-chain mRNA was also reduced in AACQ versus AAC (P < 0.05). However, extracellular regulated kinase 1/2 phosphorylation was similar in AAC versus AACQ. The level of aortic endothelial dysfunction (wire myography) was also similar between AAC and AACQ, in spite of reduced aortic thickening in AACQ. Importantly, Q-treated rats did not show any deleterious changes in myocardial function (echocardiography). Our data supports an antihypertensive and antihypertrophic effect of Q in vivo in the absence of changes concerning vascular and myocardial function.
Collapse
Affiliation(s)
- Thunder Jalili
- College of Health, University of Utah, Salt Lake City, USA.
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Kregel KC, Zhang HJ. An integrated view of oxidative stress in aging: basic mechanisms, functional effects, and pathological considerations. Am J Physiol Regul Integr Comp Physiol 2006; 292:R18-36. [PMID: 16917020 DOI: 10.1152/ajpregu.00327.2006] [Citation(s) in RCA: 533] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aging is an inherently complex process that is manifested within an organism at genetic, molecular, cellular, organ, and system levels. Although the fundamental mechanisms are still poorly understood, a growing body of evidence points toward reactive oxygen species (ROS) as one of the primary determinants of aging. The "oxidative stress theory" holds that a progressive and irreversible accumulation of oxidative damage caused by ROS impacts on critical aspects of the aging process and contributes to impaired physiological function, increased incidence of disease, and a reduction in life span. While compelling correlative data have been generated to support the oxidative stress theory, a direct cause-and-effect relationship between the accumulation of oxidatively mediated damage and aging has not been strongly established. The goal of this minireview is to broadly describe mechanisms of in vivo ROS generation, examine the potential impact of ROS and oxidative damage on cellular function, and evaluate how these responses change with aging in physiologically relevant situations. In addition, the mounting genetic evidence that links oxidative stress to aging is discussed, as well as the potential challenges and benefits associated with the development of anti-aging interventions and therapies.
Collapse
Affiliation(s)
- Kevin C Kregel
- Department of Integrative Physiology and Free Radical and Radiation Biology Program, Department of Radiation Oncology, The University of Iowa, Iowa City, IA 52242, USA.
| | | |
Collapse
|
30
|
Smith AR, Visioli F, Hagen TM. Plasma membrane-associated endothelial nitric oxide synthase and activity in aging rat aortic vascular endothelia markedly decline with age. Arch Biochem Biophys 2006; 454:100-5. [PMID: 16982030 DOI: 10.1016/j.abb.2006.02.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 02/21/2006] [Accepted: 02/21/2006] [Indexed: 11/16/2022]
Abstract
The mechanisms leading to the age-related loss of endothelial nitric oxide (NO) and NO-dependent vasodilation remain largely unknown. Freshly isolated endothelium from young (6 months) and old (36 months) F344xBrN rats were analyzed for endothelial nitric oxide synthase (eNOS) protein, its subcellular distribution, and association with regulatory proteins. Results show that both vessel ring vasoreactivity and A23187-induced eNOS activity in isolated endothelial cells significantly (p < or = 0.05) declined with age. Levels of cGMP, a reliable marker for NO bioactivity also declined significantly (p < or = 0.01). However, no change in overall eNOS protein was evident. Subcellular fractionation studies revealed an age-related loss in active, plasma membrane-bound eNOS relative to eNOS in the Golgi/cytosol of the endothelium. Plasma membrane-associated eNOS in aged endothelium was also less complexed with the activating proteins Hsp90 and Akt and more associated with to caveolin-1, which inhibits eNOS activity. These results suggest that age-dependent loss of NO may be partly caused by differences in eNOS subcellular distribution and its association with inhibitory proteins.
Collapse
Affiliation(s)
- Anthony R Smith
- Linus Pauling Institute and Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
| | | | | |
Collapse
|
31
|
Brown KA, Chu Y, Lund DD, Heistad DD, Faraci FM. Gene transfer of extracellular superoxide dismutase protects against vascular dysfunction with aging. Am J Physiol Heart Circ Physiol 2006; 290:H2600-5. [PMID: 16443677 DOI: 10.1152/ajpheart.00676.2005] [Citation(s) in RCA: 46] [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
Aging is an independent risk factor for cardiovascular disease, but mechanisms leading to vascular dysfunction have not been fully elucidated. Recent studies suggest that oxidative stress may increase in blood vessels during aging. Levels of superoxide are influenced by the activity of SODs. The goal of this study was to examine the effect of extracellular superoxide dismutase (ECSOD) on superoxide levels and vascular function in an animal model of aging. Aortas from young (4-8 mo old) and old (29-31 mo old) Fischer 344 rats were examined in vitro. Relaxation of aorta to ACh was impaired in old rats compared with young rats; e.g., 3 muM ACh produced 57 +/- 4% (mean +/- SE) and 84 +/- 2% relaxation in old and young rats, respectively (P < 0.0001). Three days after gene transfer of adenovirus expressing human ECSOD (AdECSOD), the response to ACh was not affected in young rats but was improved in old rats. There was no difference in relaxation to the endothelium-independent dilator sodium nitroprusside between young, aged, and AdECSOD-treated old rats. Superoxide levels (lucigenin-enhanced chemiluminescence) were significantly increased in aged rats compared with young rats. After gene transfer of ECSOD to aged rats, superoxide levels in aorta were similar in old and young rats. Gene transfer of an ECSOD with the heparin-binding domain deleted had no effect on vascular function or superoxide levels in old rats. These results suggest that 1) vascular dysfunction associated with aging is mediated in part by increased levels of superoxide, 2) gene transfer of ECSOD reduces vascular superoxide and dysfunction in old rats, and 3) beneficial effects of ECSOD in old rats require the heparin-binding domain of ECSOD.
Collapse
Affiliation(s)
- Kathryn A Brown
- Department of Pharmacology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | | | | | | | | |
Collapse
|
32
|
De la Fuente M, Hernanz A, Vallejo MC. The immune system in the oxidative stress conditions of aging and hypertension: favorable effects of antioxidants and physical exercise. Antioxid Redox Signal 2005; 7:1356-66. [PMID: 16115041 DOI: 10.1089/ars.2005.7.1356] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Several studies have shown that both oxidative stress and inflammation are linked to the process of hypertension and that the immune system is also involved in this age-related process. More specifically, the oxygen stress related to immune system dysfunction seems to have a key role in senescence, in agreement with the oxidation/ inflammation theory of aging. From a practical point of view, and according to our own research, the immune functions change in a similar fashion in hypertension and aging. As antioxidant diet supplementation decreases oxidative stress, it may be useful to treat hypertension and increase longevity. Probably, these favorable effects are mediated by an antioxidant-induced improvement of the immune function. The practice of moderate physical exercise shows similar favorable effects, and indeed our studies on exercising hypertensive women demonstrate an improved immune function, probably linked to raised levels of intracellular antioxidant defenses. The present review summarizes a selection of data related to the above from other authors as well as some findings from our own work.
Collapse
Affiliation(s)
- M De la Fuente
- Department of Physiology (Animal Physiology II), Faculty of Biological Sciences, Complutense University, Madrid, Spain.
| | | | | |
Collapse
|
33
|
Afanas'ev IB. Free Radical Mechanisms of Aging Processes Under Physiological Conditions. Biogerontology 2005; 6:283-90. [PMID: 16333762 DOI: 10.1007/s10522-005-2626-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Accepted: 05/03/2005] [Indexed: 01/22/2023]
Abstract
Free radical theory of aging predicts crucial role for free radicals produced by external factors (environmental contamination, irradiation, etc.) or pathological disorders (hereditary diseases or infections) in the initiation of aging. Does it mean that under hypothetical completely physiological conditions aging processes could be fully suppressed? To answer this question, we will consider the possible mechanisms of free radical formation in such hypothetical state. There are two major mechanisms, which are responsible for free radical-mediated damage in a living organism: superoxide overproduction by mitochondria and nonenzymatic lipid peroxidation. Superoxide overproduction causes the inhibition of nitric oxide formation and bioavailability, one of principal characteristics of aging, while nonenzymatic lipid peroxidation, which is already demonstrated at physiological conditions, produces toxic isoprostanes. We suggest that major initiators of free radical-mediated damaging processes leading to aging at physiological state are oxidizable components of diet. The possibility of inhibition of aging processes by supplementation of nontoxic antioxidants and calorie restriction is discussed. Scheme demonstrating the potential mechanisms of starting the free radical-mediated aging processes is presented, which are discussed on the grounds of known literature data.
Collapse
Affiliation(s)
- Igor B Afanas'ev
- Vitamin Research Institute, Nauchny pr. 14A, 117820, Moscow, Russia.
| |
Collapse
|
34
|
Madamanchi NR, Hakim ZS, Runge MS. Oxidative stress in atherogenesis and arterial thrombosis: the disconnect between cellular studies and clinical outcomes. J Thromb Haemost 2005; 3:254-67. [PMID: 15670030 DOI: 10.1111/j.1538-7836.2004.01085.x] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Atherosclerosis is a multifactorial disease for which the molecular etiology of many of the risk factors is still unknown. As no single genetic marker or test accurately predicts cardiovascular death, phenotyping for markers of inflammation may identify the individuals at risk for vascular diseases. Reactive oxygen species (ROS) are key mediators of signaling pathways that underlie vascular inflammation in atherogenesis, starting from the initiation of fatty streak development through lesion progression to ultimate plaque rupture. Various animal models of atherosclerosis support the notion that ROS released from NAD(P)H oxidases, xanthine oxidase, lipoxygenases, and enhanced ROS production from dysfunctional mitochondrial respiratory chain indeed have a causatory role in atherosclerosis and other vascular diseases. Human investigations also support the oxidative stress hypothesis of atherogenesis. This is further supported by the observed impairment of vascular function and enhanced atherogenesis in animal models that have deficiencies in antioxidant enzymes. The importance of oxidative stress in atherosclerosis is further emphasized because of its role as a unifying mechanism across many vascular diseases. The main contraindicator for the role oxidative stress plays in atherosclerosis is the lack of effectiveness of antioxidants in reducing primary endpoints of cardiovascular death and morbidity. However, this lack of effectiveness by itself does not negate the existence or causatory role of oxidative stress in vascular disease. Lack of proven markers of oxidative stress, which could help to identify a subset of population that can benefit from antioxidant supplementation, and the complexity and subcellular localization of redox reactions, are among the factors responsible for the mixed outcomes in the use of antioxidants for the prevention of cardiovascular diseases. To better understand the role of oxidative stress in vascular diseases, future studies should be aimed at using advances in mouse and human genetics to define oxidative stress phenotypes and link phenotype with genotype.
Collapse
Affiliation(s)
- N R Madamanchi
- Carolina Cardiovascular Biology Center, Department of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | | | | |
Collapse
|
35
|
Sugita M, Sugita H, Kaneki M. Increased insulin receptor substrate 1 serine phosphorylation and stress-activated protein kinase/c-Jun N-terminal kinase activation associated with vascular insulin resistance in spontaneously hypertensive rats. Hypertension 2004; 44:484-9. [PMID: 15302844 DOI: 10.1161/01.hyp.0000140778.53811.20] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Insulin resistance is associated with cardiovascular disease. Impaired insulin receptor substrate (IRS)-mediated signal transduction is a major contributor to insulin resistance. Recently, IRS-1 phosphorylation at serine 307 by stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) has been highlighted as a molecular event that causes insulin resistance. We investigated IRS-1-mediated insulin signaling, IRS-1 phosphorylation at serine 307, and SAPK/JNK activation status in the aorta of spontaneously hypertensive rats (SHR) by immunoprecipitation and immunoblotting. Insulin-stimulated tyrosine phosphorylation of insulin receptor and IRS-1 in SHR was decreased to 55% (P<0.01) and 40% (P<0.01) of the levels in Wistar-Kyoto rats (WKY), respectively. Insulin-stimulated IRS-1-associated phosphatidylinositol 3-kinase activation in SHR was reduced to 28% of the level in WKY (P<0.0001). Immunoblot analysis revealed that phosphorylated IRS-1 at serine 307 in SHR was increased to 261% (P<0.001) of the level in WKY. Phosphorylated (activated) SAPK/JNK in SHR was increased to 223% of the level in WKY (P<0.01). Serine-phosphorylated IRS-1 that was immunoprecipitated from the aorta of SHR was capable of inhibiting in vitro tyrosine phosphorylation by recombinant insulin receptor compared with WKY-derived IRS-1. These findings demonstrate that insulin resistance in the aorta of SHR was associated with elevated IRS-1 phosphorylation at serine 307 and increased SAPK/JNK activation. The present study suggests that increased SAPK/JNK activation may play an important role in the pathogenesis of vascular insulin resistance via inhibitory serine phosphorylation of IRS-1.
Collapse
Affiliation(s)
- Michiko Sugita
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | | | | |
Collapse
|
36
|
Abstract
Over the past several years, the insulin/insulin-like growth factor (IGF) signaling pathway has become a central figure in the study of organismal aging. Mutations in components of this pathway have led to enhanced longevity in several organisms, but it is still not clear whether and how this pathway contributes to human aging and aging-related diseases. In a new study, Miyauchi and colleagues propose that Akt, a member of the phosphatidylinositol 3-kinase family and a downstream component of the insulin/IGF pathway, plays a central role in the life span of endothelial cells. These findings implicate the insulin/IGF pathway in the development and progression of cardiovascular disease.
Collapse
|
37
|
Wynne FL, Payne JA, Cain AE, Reckelhoff JF, Khalil RA. Age-related reduction in estrogen receptor-mediated mechanisms of vascular relaxation in female spontaneously hypertensive rats. Hypertension 2003; 43:405-12. [PMID: 14699001 DOI: 10.1161/01.hyp.0000111833.82664.0c] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hypertension increases with aging, and changes in vascular estrogen receptors (ERs) may play a role in age-related hypertension in women. We tested whether age-related increases in blood pressure in female spontaneously hypertensive rats (SHRs) are associated with reduction in amount and/or vascular relaxation effects of estrogen and ER. Arterial pressure and plasma estradiol were measured in adult (12 weeks) and aging (16 months) female SHRs, and thoracic aorta was isolated for measurement of active stress, 45Ca2+ influx, and ERs. Arterial pressure was greater and plasma estradiol was less in aging females than in adult females. In aorta of adult females, Western blots revealed alpha- and beta-ERs that were slightly reduced in aging rats. In endothelium-intact vascular strips, phenylephrine (Phe; 10(-5) mol/L) caused greater active stress in aging rats (9.3+/-0.2) than in adult rats (6.2+/-0.3x10(4) N/m2). 17beta-estradiol (E2) caused relaxation of Phe contraction and stimulation of vascular nitrite/nitrate production, which was reduced in aging rats. In endothelium-denuded strips, E2 still caused relaxation of Phe contraction, which was smaller in aging rats than adult rats. KCl (51 mmol/L), which stimulates Ca2+ influx, produced greater active stress in aging rats (9.1+/-0.3) than in adult rats (5.9+/-0.2x10(4) N/m2). E2 caused relaxation of KCl contraction and inhibition of Phe- and KCl-induced 45Ca2+ influx, which were reduced in aging rats. Thus, aging in female SHR is associated with reduction in ER-mediated NO production from endothelial cells and decrease in inhibitory effects of estrogen on Ca2+ entry mechanisms of smooth muscle contraction. The age-related decrease in ER-mediated vascular relaxation may explain the increased vascular contraction and arterial pressure associated with aging in females.
Collapse
Affiliation(s)
- Fanisha L Wynne
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, USA
| | | | | | | | | |
Collapse
|
38
|
Solhaug MJ. Pathophysiological role for oxidative stress in geriatric vascular dysfunction. Am J Physiol Regul Integr Comp Physiol 2003; 285:R524-5. [PMID: 12909580 DOI: 10.1152/ajpregu.00302.2003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|