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Prajjwal P, Marsool MDM, Inban P, Sharma B, Asharaf S, Aleti S, Gadam S, Al Sakini AS, Hadi DD. Vascular dementia subtypes, pathophysiology, genetics, neuroimaging, biomarkers, and treatment updates along with its association with Alzheimer's dementia and diabetes mellitus. Dis Mon 2023; 69:101557. [PMID: 37031059 DOI: 10.1016/j.disamonth.2023.101557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2023]
Abstract
Dementia is a chronic progressive cognitive decline illness that results in functional impairment. Vascular dementia (VaD), second only to Alzheimer's disease (AD), is one of the most prevalent forms of dementia in the elderly (aged over 65 years), with a varied presentation and unpredictable disease development caused by cerebrovascular or cardiovascular illness. To get a better understanding of the changes occurring in the brain and to drive therapy efforts, new biomarkers for early and precise diagnosis of AD and VaD are required. In this review, Firstly, we describe the subtypes of vascular dementia, their clinical features, pathogenesis, genetics implemented, and their associated neuroimaging and biomarkers, while describing extensively the recent biomarkers discovered in the literature. Secondly, we describe some of the well-documented and other less-defined risk factors and their association and pathophysiology in relation to vascular dementia. Finally, we follow recent updates in the management of vascular dementia along with its association and differentiation from Alzheimer's disease. The aim of this review is to gather the scattered updates and the most recent changes in blood, CSF, and neuroimaging biomarkers related to the multiple subtypes of vascular dementia along with its association with Alzheimer's dementia and diabetes mellitus.
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Affiliation(s)
| | | | - Pugazhendi Inban
- Internal Medicine, Government Medical College, Omandurar, Chennai, India
| | | | - Shahnaz Asharaf
- Internal Medicine, Travancore Medical College, Kollam, Kerala, India
| | - Soumya Aleti
- PGY-2, Internal Medicine, Berkshire Medical Center, Pittsfield, MA, USA
| | - Srikanth Gadam
- Internal Medicine, Postdoctoral Research Fellow, Mayo Clinic, USA
| | | | - Dalia Dhia Hadi
- University of Baghdad, Al-Kindy College of Medicine, Baghdad, Iraq
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Yamamoto Y, Liao YC, Lee YC, Ihara M, Choi JC. Update on the Epidemiology, Pathogenesis, and Biomarkers of Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy. J Clin Neurol 2023; 19:12-27. [PMID: 36606642 PMCID: PMC9833879 DOI: 10.3988/jcn.2023.19.1.12] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/06/2022] [Accepted: 11/09/2022] [Indexed: 01/04/2023] Open
Abstract
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common monogenic disorder of the cerebral small blood vessels. It is caused by mutations in the NOTCH3 gene on chromosome 19, and more than 280 distinct pathogenic mutations have been reported to date. CADASIL was once considered a very rare disease with an estimated prevalence of 1.3-4.1 per 100,000 adults. However, recent large-scale genomic studies have revealed a high prevalence of pathogenic NOTCH3 variants among the general population, with the highest risk being among Asians. The disease severity and age at onset vary significantly even among individuals who carry the same NOTCH3 mutations. It is still unclear whether a significant genotype-phenotype correlation is present in CADASIL. The accumulation of granular osmiophilic material in the vasculature is a characteristic feature of CADASIL. However, the exact pathogenesis of CADASIL remains largely unclear despite various laboratory and clinical observations being made. Major hypotheses proposed so far have included aberrant NOTCH3 signaling, toxic aggregation, and abnormal matrisomes. Several characteristic features have been observed in the brain magnetic resonance images of patients with CADASIL, including subcortical lacunar lesions and white matter hyperintensities in the anterior temporal lobe or external capsule, which were useful in differentiating CADASIL from sporadic stroke in patients. The number of lacunes and the degree of brain atrophy were useful in predicting the clinical outcomes of patients with CADASIL. Several promising blood biomarkers have also recently been discovered for CADASIL, which require further research for validation.
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Affiliation(s)
- Yumi Yamamoto
- Department of Neurology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Yi-Chu Liao
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan.,Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yi-Chung Lee
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan.,Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Masafumi Ihara
- Department of Neurology, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Jay Chol Choi
- Department of Neurology, Jeju National University, Jeju, Korea.,Institute for Medical Science, Jeju National University, Jeju, Korea
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3
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Aerobic exercise increases sprouting angiogenesis in the male rat motor cortex. Brain Struct Funct 2020; 225:2301-2314. [PMID: 32918614 DOI: 10.1007/s00429-020-02100-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 06/10/2020] [Indexed: 12/14/2022]
Abstract
Exercise is beneficial to brain health, and historically, the advantageous effects of exercise on the brain have been attributed to neuronal plasticity. However, it has also become clear that the brain vascular system also exhibits plasticity in response to exercise. This plasticity occurs in areas involved in movement, such as the motor cortex. This experiment aimed to further characterize the effects of exercise on structural vascular plasticity in the male rat motor cortex, by specifically identifying whether features of angiogenesis, the growth of new capillaries, or changes in vessel diameter were present. Male rats in the exercise group engaged in a 5-week bout of voluntary wheel running, while a second group of rats remained sedentary. After the exercise regimen, vascular corrosion casts, resin replicas of the brain vasculature, were made for all animals and imaged using a scanning electron microscope. Results indicate sprouting angiogenesis was the primary form of structural vascular plasticity detected in the motor cortex under these aerobic exercise parameters. Additionally, exercised rats displayed a slight increase in capillary diameter and expanded endothelial cell nuclei diameters in this region.
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Belikov AV. Age-related diseases as vicious cycles. Ageing Res Rev 2019; 49:11-26. [PMID: 30458244 DOI: 10.1016/j.arr.2018.11.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 10/05/2018] [Accepted: 11/15/2018] [Indexed: 02/07/2023]
Abstract
The mortality rates of age-related diseases (ARDs) increase exponentially with age. Processes described by the exponential growth function typically involve a branching chain reaction or, more generally, a positive feedback loop. Here I propose that each ARD is mediated by one or several positive feedback loops (vicious cycles). I then identify critical vicious cycles in five major ARDs: atherosclerosis, hypertension, diabetes, Alzheimer's and Parkinson's. I also propose that the progression of ARDs can be halted by selectively interrupting the vicious cycles and suggest the most promising targets.
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Affiliation(s)
- Aleksey V Belikov
- Laboratory of Innovative Medicine, School of Biological and Medical Physics, Moscow Institute of Physics and Technology, Institutsky per., 9, 141701 Dolgoprudny, Moscow Region, Russia.
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Vascular structural and functional changes: their association with causality in hypertension: models, remodeling and relevance. Hypertens Res 2016; 40:311-323. [PMID: 27784889 DOI: 10.1038/hr.2016.145] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 09/09/2016] [Accepted: 09/26/2016] [Indexed: 12/22/2022]
Abstract
Essential hypertension is a complex multifactorial disease process that involves the interaction of multiple genes at various loci throughout the genome, and the influence of environmental factors such as diet and lifestyle, to ultimately determine long-term arterial pressure. These factors converge with physiological signaling pathways to regulate the set-point of long-term blood pressure. In hypertension, structural changes in arteries occur and show differences within and between vascular beds, between species, models and sexes. Such changes can also reflect the development of hypertension, and the levels of circulating humoral and vasoactive compounds. The role of perivascular adipose tissue in the modulation of vascular structure under various disease states such as hypertension, obesity and metabolic syndrome is an emerging area of research, and is likely to contribute to the heterogeneity described in this review. Diversity in structure and related function is the norm, with morphological changes being causative in some beds and states, and in others, a consequence of hypertension. Specific animal models of hypertension have advantages and limitations, each with factors influencing the relevance of the model to the human hypertensive state/s. However, understanding the fundamental properties of artery function and how these relate to signalling mechanisms in real (intact) tissues is key for translating isolated cell and model data to have an impact and relevance in human disease etiology. Indeed, the ultimate aim of developing new treatments to correct vascular dysfunction requires understanding and recognition of the limitations of the methodologies used.
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Affiliation(s)
- Daniel N Meijles
- From the Department of Pharmacology and Chemical Biology, Vascular Medicine Institute, University of Pittsburgh, PA
| | - Patrick J Pagano
- From the Department of Pharmacology and Chemical Biology, Vascular Medicine Institute, University of Pittsburgh, PA.
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Pires PW, Dams Ramos CM, Matin N, Dorrance AM. The effects of hypertension on the cerebral circulation. Am J Physiol Heart Circ Physiol 2013; 304:H1598-614. [PMID: 23585139 DOI: 10.1152/ajpheart.00490.2012] [Citation(s) in RCA: 250] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Maintenance of brain function depends on a constant blood supply. Deficits in cerebral blood flow are linked to cognitive decline, and they have detrimental effects on the outcome of ischemia. Hypertension causes alterations in cerebral artery structure and function that can impair blood flow, particularly during an ischemic insult or during periods of low arterial pressure. This review will focus on the historical discoveries, novel developments, and knowledge gaps in 1) hypertensive cerebral artery remodeling, 2) vascular function with emphasis on myogenic reactivity and endothelium-dependent dilation, and 3) blood-brain barrier function. Hypertensive artery remodeling results in reduction in the lumen diameter and an increase in the wall-to-lumen ratio in most cerebral arteries; this is linked to reduced blood flow postischemia and increased ischemic damage. Many factors that are increased in hypertension stimulate remodeling; these include the renin-angiotensin-aldosterone system and reactive oxygen species levels. Endothelial function, vital for endothelium-mediated dilation and regulation of myogenic reactivity, is impaired in hypertension. This is a consequence of alterations in vasodilator mechanisms involving nitric oxide, epoxyeicosatrienoic acids, and ion channels, including calcium-activated potassium channels and transient receptor potential vanilloid channel 4. Hypertension causes blood-brain barrier breakdown by mechanisms involving inflammation, oxidative stress, and vasoactive circulating molecules. This exposes neurons to cytotoxic molecules, leading to neuronal loss, cognitive decline, and impaired recovery from ischemia. As the population ages and the incidence of hypertension, stroke, and dementia increases, it is imperative that we gain a better understanding of the control of cerebral artery function in health and disease.
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Affiliation(s)
- Paulo W Pires
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
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Ritt M, Harazny JM, Ott C, Raff U, Schneider MP, Michelson G, Schmieder RE. Basal nitric oxide activity is an independent determinant of arteriolar structure in the human retinal circulation. J Hypertens 2011; 29:123-9. [DOI: 10.1097/hjh.0b013e3283406940] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Dynamic expression of proteins associated with adventitial remodeling in adventitial fibroblasts from spontaneously hypertensive rats. Acta Pharmacol Sin 2010; 31:1312-8. [PMID: 20802504 DOI: 10.1038/aps.2010.88] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
AIM To identify proteins that could potentially be involved in adventitial remodeling in vascular adventitial fibroblasts (AFs) from spontaneously hypertensive rats (SHR). METHODS AFs were isolated from thoracic aortas of 4-, 8-, 16-, and 24-week-old male SHR and Wistar-Kyoto (WKY) rats and cultured to passage 4. Proteomic differential expression profiles between SHR-AFs and WKY-AFs were investigated using 2-D electrophoresis (2-DE), whereas gel image analysis was processed using Image Master 2D Platinum. Protein spots were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Expression levels of annexin A1 in AFs and aortas from SHR and WKY rats were detected with Western blotting and immunofluorescence techniques. RESULTS In 4-, 8-, 16-, and 24-week-old SHR-AFs, 49, 59, 54, and 69 protein spots were found to have significant differences from the age-matched WKY-AFs. Fourteen spots with the same changes in patterns were analyzed in 4-, 8-, 16-, and 24-week-old SHR-AFs with mass spectrometry. Except for cytoskeleton proteins such as tubulin beta 5, it was found that annexin A1, translation elongation factor Tu, endoplasmic reticulum protein 29 and calcium-binding protein 1 were expressed in vascular AFs and their levels changed significantly in SHR-AFs compared with those in WKY-AFs. A decrease in annexin A1 in SHR-AFs was confirmed with Western blotting and immunofluorescence staining at the cell and tissue levels. CONCLUSION The application of proteomic techniques revealed a number of novel proteins involved in adventitial remodeling of AFs from SHR, which provide new mechanisms responsible for the occurrence and development of hypertension and potential targets for influencing vascular remodeling in hypertension.
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Osmond JM, Mintz JD, Stepp DW. Preventing increased blood pressure in the obese Zucker rat improves severity of stroke. Am J Physiol Heart Circ Physiol 2010; 299:H55-61. [PMID: 20418477 DOI: 10.1152/ajpheart.01111.2009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Obesity is a risk factor for stroke, but the determinants of increased stroke risk in obesity are unknown. We have previously reported that obese Zucker rats (OZRs) have a worse stroke outcome and display evidence of remodeling of the middle cerebral artery (MCA), in parallel with hypertension, compared with lean controls. This study tested the hypothesis that hypertension is an essential determinant of cerebral vascular remodeling and increased stroke damage in OZRs. Blood pressure was measured by telemetry in lean and obese rats with and without hydrochlorthiazide (HCT; 2 mg.kg(-1).day(-1)) from 8 to 15 wk of age. A separate group of rats was also chronically fed a low-sodium (LS) diet. Vessel structure was assessed in isolated, pressurized MCAs. Cerebral ischemia was induced for 60 min using an intralumenal suture technique, followed by 24 h of reperfusion. HCT treatment effectively prevented the increase in blood pressure in obese rats; however, the LS diet did not lower pressure. Importantly, infarct size was normalized by HCT after ischemia-reperfusion injury. Additionally, HCT improved the changes in MCA structure observed in untreated OZRs. There were no benefits of the LS diet on stroke injury or vessel structure. These results indicate that increased pressure is essential for driving the changes in infarct size in OZRs.
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Affiliation(s)
- Jessica M Osmond
- Vascular Biology Center, Medical College of Georgia, 1459 Laney Walker Blvd., Augusta, GA 30912, USA
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Csányi G, Taylor WR, Pagano PJ. NOX and inflammation in the vascular adventitia. Free Radic Biol Med 2009; 47:1254-66. [PMID: 19628034 PMCID: PMC3061339 DOI: 10.1016/j.freeradbiomed.2009.07.022] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 07/10/2009] [Accepted: 07/14/2009] [Indexed: 02/07/2023]
Abstract
Vascular inflammation has traditionally been thought to be initiated at the luminal surface and progress through the media toward the adventitial layer. In recent years, however, evidence has emerged suggesting that the vascular adventitia is activated early in a variety of cardiovascular diseases and that it plays an important role in the initiation and progression of vascular inflammation. Adventitial fibroblasts have been shown to produce substantial amounts of NAD(P)H oxidase-derived reactive oxygen species (ROS) in response to vascular injury. Additionally, inflammatory cytokines, lipids, and various hormones, implicated in fibroblast proliferation and migration, lead to recruitment of inflammatory cells to the adventitial layer and impairment of endothelium-dependent relaxation. Early in the development of vascular disease, there is clear evidence for progression toward a denser vasa vasorum which delivers oxygen and nutrients to an increasingly hypoxic and nutrient-deficient media. This expanded vascularization appears to provide enhanced delivery of inflammatory cells to the adventitia and outer media. Combined adventitial fibroblast and inflammatory cell-derived ROS therefore are expected to synergize their local effect on adventitial parenchymal cells, leading to further cytokine release and a feed-forward propagation of adventitial ROS production. In fact, data from our laboratory and others suggest a broader paracrine positive feedback role for adventitia-derived ROS in medial smooth muscle cell hypertrophy and neointimal hyperplasia. A likely candidate responsible for the adventitia-derived paracrine signaling across the vessel wall is the superoxide anion metabolite hydrogen peroxide, which is highly stable, cell permeant, and capable of activating downstream signaling mechanisms in smooth muscle cells, leading to phenotypic modulation of smooth muscle cells. This review addresses the role of adventitial NAD(P)H oxidase-derived ROS from a nontraditional, perivascular vantage of promoting vascular inflammation and will discuss how ROS derived from adventitial NAD(P)H oxidases may be a catalyst for vascular remodeling and dysfunction.
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Affiliation(s)
- Gábor Csányi
- Department of Pharmacology & Chemical Biology and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA
| | - W. Robert Taylor
- Departments of Medicine and Biomedical Engineering, Emory University and the Atlanta VA Medical Center, Atlanta, GA
| | - Patrick J. Pagano
- Department of Pharmacology & Chemical Biology and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA
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Wall-to-lumen ratio of retinal arterioles is related with urinary albumin excretion and altered vascular reactivity to infusion of the nitric oxide synthase inhibitor N-monomethyl-L-arginine. J Hypertens 2009; 27:2201-8. [DOI: 10.1097/hjh.0b013e32833013fd] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ritt M, Schmieder RE. Wall-to-Lumen Ratio of Retinal Arterioles as a Tool to Assess Vascular Changes. Hypertension 2009; 54:384-7. [DOI: 10.1161/hypertensionaha.109.133025] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Martin Ritt
- From the Department of Nephrology and Hypertension, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Roland E. Schmieder
- From the Department of Nephrology and Hypertension, University of Erlangen-Nürnberg, Erlangen, Germany
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Estrogen deficiency-induced alterations of vascular MMP-2, MT1-MMP, and TIMP-2 in ovariectomized rats. Am J Hypertens 2009; 22:27-34. [PMID: 19023275 DOI: 10.1038/ajh.2008.306] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Matrix metalloproteinases (MMPs) activity may modulate hypertension-related accumulation of extracellular matrix (ECM) in arteries. We tested whether estrogen deficiency induces alterations of vascular collagen, MMP-2, membrane-type 1-MMP (MT1-MMP), or tissue inhibitor of metalloproteinases-2 (TIMP-2) expression in ovariectomized rats, which may be associated with postmenopausal hypertension. METHODS Estrogen deficiency was induced by ovariectomy (Ovx) in female rats. Time-course changes of aortic MMPs protein expression were evaluated. Treatment with tempol or aminoguanidine was used to examine the role of oxidative stress and nitric oxide (NO) on these changes. RESULTS The level of the active-form MMP-2 was markedly reduced during 1-4 weeks after Ovx, with a significant increase in collagen accumulation and increased MT1-MMP expression. Although active-form MMP-2 and collagen progressively returned to normal levels, the markedly increased collagen deposition appeared again at 8 weeks and persisted until 12 weeks, followed by induction of MMP-2 and MT1-MMP at 12 weeks. The TIMP-2 level reduced for 2 weeks after Ovx, but soon returned to normal. Treatment with 17beta-estradiol (E(2)), tempol, or aminoguanidine for 6 weeks prevented Ovx-induced blood pressure elevation and apparently reversed the MMPs changes. CONCLUSIONS In an initial period, E(2) deficiency induces a reduction of active-form MMP-2 leading to collagen accumulation, and induction of MT1-MMP, which may be a compensatory response to degrade collagen. At a latter stage, the concurrent elevation of active-form MMP-2 and MT1-MMP expression may be adaptive responses to regulate ECM composition in the vascular wall. Oxidative stress and NO contribute to activity modulation of vascular MMPs in Ovx rats.
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Osmond JM, Mintz JD, Dalton B, Stepp DW. Obesity increases blood pressure, cerebral vascular remodeling, and severity of stroke in the Zucker rat. Hypertension 2008; 53:381-6. [PMID: 19104000 DOI: 10.1161/hypertensionaha.108.124149] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Obesity is a risk factor for stroke, but the mechanisms by which obesity increases stroke risk are unknown. Because microvascular architecture contributes to the outcome of stroke, we hypothesized that middle cerebral arteries (MCAs) from obese Zucker rats (OZRs) undergo inward remodeling and develop increased myogenic tone compared with those in lean Zucker rats (LZRs). We further hypothesized that OZRs have an increased infarct after cerebral ischemia and that changes in vascular structure and function correlate with the development of hypertension in OZRs. Blood pressure was measured by telemetry in LZRs and OZRs from 6 to 17 weeks of age. Vessel structure and function were assessed in isolated MCAs. Stroke damage was assessed after ischemia was induced for 60 minutes followed by 24 hours of reperfusion. Although mean arterial pressure was similar between young rats (6 to 8 weeks old), mean arterial pressure was higher in adult (14 to 17 weeks old) OZRs than in LZRs. MCAs from OZRs had a smaller lumen diameter and increased myogenic vasoconstriction compared with those from LZRs. After ischemia, infarction was 58% larger in OZRs than in LZRs. Before the development of hypertension, MCA myogenic reactivity and lumen diameter, as well as infarct size, were similar between young LZRs and OZRs. Our results indicate that the MCAs of OZRs undergo structural remodeling and that these rats have greater cerebral injury after cerebral ischemia. These cerebrovascular changes correlate with the development of hypertension and suggest that the increased blood pressure may be the major determinant for stroke risk in obese individuals.
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Affiliation(s)
- Jessica M Osmond
- Department of Physiology, Vascular Biology Center, Medical College of Georgia, 1459 Laney Walker Blvd, CB3212A, Augusta, GA 30912, USA
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Hypertension increases middle cerebral artery resting tone in spontaneously hypertensive rats: role of tonic vasoactive factor availability. Clin Sci (Lond) 2008; 114:651-9. [DOI: 10.1042/cs20070361] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The present study explores the contribution of alterations in resting tone to cerebral artery narrowing in SHRs (spontaneously hypertensive rats) and the role of hypertension development. Young pre-hypertensive and adult fully hypertensive SHRs and age-matched Wistar–Kyoto rat controls were used. The contribution of basal vasoactive factors to resting tone was studied in middle cerebral arteries with pressure myography. Basal NO and O2− (superoxide anion) availability were determined with fluorescent indicators using confocal microscopy and lucigenin-enhanced chemiluminescence. Basal O2− was also assessed in mesenteric resistance arteries. Middle cerebral arteries from adult rats, but not young pre-hypertensive rats, had augmented myogenic responses and resting tone and decreased relaxation to sodium nitroprusside compared with their normotensive counterparts. Cerebral arteries from adult SHRs also had an increase in tonic NO associated with a decrease in basal O2− availability. Basal O2− was instead increased in mesenteric arteries from SHRs. The present results indicate that large cerebral arteries from SHRs have an increase in their resting tone as a consequence of sustained hypertension and that this is related to a decrease in NO responsiveness. We suggest that this increase in resting tone and myogenic responses could act as a protective mechanism against the development of stroke in SHRs. The present study also demonstrates some unusual findings regarding the current understanding of the NO/O2− balance in hypertension with important differences between vascular beds and draws attention to the complexity of this balance in cardiovascular health and disease.
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Abstract
In the present review, microvascular remodelling refers to alterations in the structure of resistance vessels contributing to elevated systemic vascular resistance in hypertension. We start with some historical aspects, underscoring the importance of Folkow's contribution made half a century ago. We then move to some basic concepts on the biomechanics of blood vessels, and explicit the definitions proposed by Mulvany for specific forms of remodelling, especially inward eutrophic and inward hypertrophic. The available evidence for the existence of remodelled resistance vessels in hypertension comes next, with relatively more weight given to human, in comparison with animal data. Mechanisms are discussed. The impact of antihypertensive drug treatment on remodelling is described, again with emphasis on human data. Some details are given on the three studies to date which point to remodelling of subcutaneous resistance arteries as an independent predictor of cardiovascular risk in hypertensive patients. We terminate by considering the potential role of remodelling in the pathogenesis of end-organ damage and in the perpetuation of hypertension.
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Affiliation(s)
- François Feihl
- Division de Physiopathologie Clinique, Département de Médecine, Centre Hospitalier Universitaire Vaudois and Université de Lausanne, Rue du Bugnon 46, BH10-701, CH-1011 Lausanne, Switzerland.
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Pagano PJ, Gutterman DD. The adventitia: the outs and ins of vascular disease. Cardiovasc Res 2007; 75:636-9. [PMID: 17678636 PMCID: PMC3897155 DOI: 10.1016/j.cardiores.2007.07.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Accepted: 07/13/2007] [Indexed: 11/21/2022] Open
Affiliation(s)
- Patrick J. Pagano
- Hypertension and Vascular Research Division Henry Ford Hospital, Detroit MI
| | - David D. Gutterman
- Medical College of Wisconsin Cardiovascular Medicine, Pharmacology and Toxicology 8701 Watertown Plank Road Milwaukee, WI 53226 UNITED STATES
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Abstract
Blood vessels are capable of structural changes in a dynamic process called 'vascular remodelling', which involves cell growth, death, phenotypic change and migration, as well as extracellular matrix synthesis and degradation. An integrated view of the interrelationships of the different elements of the arterial wall is made possible by fluorescence confocal microscopy which enables collection of serial optical sections of relatively thick specimens without the need to cut them as with conventional histology. With the aid of image analysis software, these serial sections can be further reconstructed to obtain 3-D images, where the structures of interest are localized and quantified. Confocal microscopy can be combined with pressure myography to obtain, simultaneously, information on vascular function and 3-D structure at near-to-physiological conditions. There are a vast number of fluorescent compounds useful for imaging vessel structure and function. Nuclear dyes allow the identification of the different types of vascular cells and the quantification of their number, shape and orientation. The speed of confocal image acquisition and processing makes it possible to scan entire intact arteries stained with fluorescent kits or antibodies to locate infrequent events such as cell apoptosis, proliferation or migration. Confocal microscopy is not only useful for imaging vascular wall structure, but also to visualize and quantify, by the intensity of fluorescence, the generation of vascular cell factors such as nitric oxide or superoxide anion. In conclusion, confocal microscopy and image analysis software provide insight into vascular wall structure and function and the active process of vascular remodelling in physiological and pathological situations.
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Affiliation(s)
- Silvia M Arribas
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
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Briones AM, Salaices M, Vila E. Mechanisms Underlying Hypertrophic Remodeling and Increased Stiffness of Mesenteric Resistance Arteries From Aged Rats. J Gerontol A Biol Sci Med Sci 2007; 62:696-706. [PMID: 17634315 DOI: 10.1093/gerona/62.7.696] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The mechanisms associated with structural and mechanical alterations of mesenteric resistance arteries from aged rats were investigated by using pressure myography, confocal microscopy, immunofluorescence, and picrosirius red staining. Arteries from old rats showed: (i) increased wall and media thickness, greater number of smooth muscle cell (SMC) layers but decreased density of SMC; (ii) increased number of adventitial cells; (iii) hypertrophy of nuclei of SMC and endothelial cells; (iv) increased stiffness associated with increased total collagen content and collagen I/III deposition in the media; and (v) similar content but changes in elastin structure in the internal elastic lamina. Hypertrophic outward remodeling in aged rat resistance arteries involve adventitial cells hyperplasia, reorganization of the same number of hypertrophied SMC in more SMC layers leading to thickened media and endothelial cell hypertrophy. Fibrosis associated with collagen deposition and changes in elastin structure might be responsible for the increased stiffness of resistance arteries from aged rats.
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Affiliation(s)
- Ana M Briones
- Departament de Farmacologia, Terapèutica i Toxicología, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
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Arribas SM, Hinek A, González MC. Elastic fibres and vascular structure in hypertension. Pharmacol Ther 2006; 111:771-91. [PMID: 16488477 DOI: 10.1016/j.pharmthera.2005.12.003] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2005] [Indexed: 01/22/2023]
Abstract
Blood vessels are dynamic structures composed of cells and extracellular matrix (ECM), which are in continuous cross-talk with each other. Thus, cellular changes in phenotype or in proliferation/death rate affect ECM synthesis. In turn, ECM elements not only provide the structural framework for vascular cells, but they also modulate cellular function through specific receptors. These ECM-cell interactions, together with neurotransmitters, hormones and the mechanical forces imposed by the heart, modulate the structural organization of the vascular wall. It is not surprising that pathological states related to alterations in the nervous, humoral or haemodynamic environment-such as hypertension-are associated with vascular wall remodeling, which, in the end, is deleterious for cardiovascular function. However, the question remains whether these structural alterations are simply a consequence of the disease or if there are early cellular or ECM alterations-determined either genetically or by environmental factors-that can predispose to vascular remodeling independent of hypertension. Elastic fibres might be key elements in the pathophysiology of hypertensive vascular remodeling. In addition to the well known effects of hypertension on elastic fibre fatigue and accelerated degradation, leading to loss of arterial wall resilience, recent investigations have highlighted new roles for individual components of elastic fibres and their degradation products. These elements can act as signal transducers and regulate cellular proliferation, migration, phenotype, and ECM degradation. In this paper, we review current knowledge regarding components of elastic fibres and discuss their possible pathomechanistic associations with vascular structural abnormalities and with hypertension development or progression.
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Affiliation(s)
- Silvia M Arribas
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, C/ Arzobispo Morcillo 2, 28029-Madrid, Spain.
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22
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Briones AM, Xavier FE, Arribas SM, González MC, Rossoni LV, Alonso MJ, Salaices M. Alterations in structure and mechanics of resistance arteries from ouabain-induced hypertensive rats. Am J Physiol Heart Circ Physiol 2006; 291:H193-201. [PMID: 16473962 DOI: 10.1152/ajpheart.00802.2005] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously described that chronic administration of ouabain induces hypertension and functional alterations in mesenteric resistance arteries. The aim of this study was to analyze whether ouabain treatment also alters the structural and mechanical properties of mesenteric resistance arteries. Wistar rats were treated for 5 wk with ouabain (8.0 microg/day sc). The vascular structure and mechanics of the third-order branches of the mesenteric artery were assessed with pressure myography and confocal microscopy. Total collagen content was determined by picrosirius red staining, collagen I/III was analyzed by Western blot, and elastin was studied by confocal microscopy. Vascular reactivity was analyzed by wire myography. Internal and external diameters and cross-sectional area were diminished, whereas the wall-to-lumen ratio was increased in arteries from ouabain-treated rats compared with controls. In addition, arteries from ouabain-treated rats were stiffer. Ouabain treatment decreased smooth muscle cell number and increased total and I/III collagens in the vascular wall. However, this treatment did not modify adventitia and media thickness, nuclei morphology, elastin structure, and vascular reactivity to norepinephrine and acetylcholine. The present work shows hypotrophic inward remodeling of mesenteric resistance arteries from ouabain-treated rats that seems to be the consequence of a combination of decreased cell number and impaired distension of the artery, possibly due to a higher stiffness associated with collagen deposition. The narrowing of resistance arteries could play a role in the pathogenesis of hypertension in this model.
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Affiliation(s)
- Ana M Briones
- Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, C/Arzobispo Morcillo, E-28029 Madrid, Spain
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23
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Wang XL, Wang J. Smoking-gene interaction and disease development: relevance to pancreatic cancer and atherosclerosis. World J Surg 2005; 29:344-53. [PMID: 15696395 DOI: 10.1007/s00268-004-7819-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
There is little doubt that cigarette smoking remains a major environmental health risk that humans are facing in the twenty-first century. Cigarette smokers are more likely to develop many forms of diseases than nonsmokers, including cancers and vascular diseases. With the availability of the human genome sequence, we become more aware of the genetic contributions to these common diseases, especially the interactive relations between environmental factors (e.g., smoking) and genes on disease susceptibility, development, and prognosis. Although smoking is responsible for up to 30% of pancreatic cancers and about 10% of cases are ascribed to genetic reasons, some genetic variants do not predispose carriers to disease development unless they are exposed to a specific adverse environment such as smoking. This smoke-gene interaction could potentially be responsible for most of the cases. Certain polymorphisms in genes such as CYP1A1 have been shown particularly sensitive to smoking-induced pathogenesis, including pancreatic cancer and atherosclerosis. We found that individuals with CYP1A1 CC genotype had a more than three fold increase in risk for severe coronary atherosclerosis when they smoked. Patients with endothelial nitric oxide synthase (eNOS) intron 4 27 repeat homozygotes were more likely to develop severe coronary stenosis when they smoked. On the other hand, DNA variants at the eNOS gene also dictate how smoking affects the expression of eNOS. We showed that GSTM1 deficiency was not involved in smoking-induced vascular diseases, but p53 polymorphisms tended to modify the disease severity in smokers. We are still at an early stage of defining the pairs and mechanisms of smoke-gene interaction, and this etiologic mechanism may hold great potential for risk assessment, treatment strategy, and prognostic predictions.
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Affiliation(s)
- Xing Li Wang
- Division of Cardiothoracic Surgery, Michael E. DeBakey Department of Surgery, MS NAB 2010, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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McGrath JC, Deighan C, Briones AM, Shafaroudi MM, McBride M, Adler J, Arribas SM, Vila E, Daly CJ. New aspects of vascular remodelling: the involvement of all vascular cell types. Exp Physiol 2005; 90:469-75. [PMID: 15894533 DOI: 10.1113/expphysiol.2005.030130] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Conventionally, the architecture of arteries is based around the close-packed smooth muscle cells and extracellular matrix. However, the adventitia and endothelium are now viewed as key players in vascular growth and repair. A new dynamic picture has emerged of blood vessels in a constant state of self-maintenance. Recent work raises fundamental questions about the cellular heterogeneity of arteries and the time course and triggering of normal and pathological remodelling. A common denominator emerging in hypertensive remodelling is an early increase in adventitial cell density suggesting that adventitial cells drive remodelling and may initiate subsequent changes such as re-arrangement of smooth muscle cells and extracellular matrix. The organization of vascular smooth muscle cells follows regular arrangements that can be modelled mathematically. In hypertension, new patterns can be quantified in these terms and give insights to how structure affects function. As with smooth muscle, little is known about the organization of the vascular endothelium, or its role in vascular remodelling. Current observations suggest that there may be a close relationship between the helical organization of smooth muscle cells and the underlying pattern of endothelial cells. The function of myoendothelial connections is a topic of great current interest and may relate to the structure of the internal elastic lamina through which the connections must pass. In hypertensive remodelling this must present an organizational challenge. The objective of this paper is to show how the functions of blood vessels depend on their architecture and a continuous interaction of different cell types and extracellular proteins.
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MESH Headings
- Animals
- Arteriosclerosis/pathology
- Blood Vessels/cytology
- Blood Vessels/pathology
- Blood Vessels/physiology
- Endothelial Cells/physiology
- Endothelium, Vascular/physiology
- Extracellular Matrix/physiology
- Humans
- Hypertension/pathology
- Intracellular Membranes/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiology
- Myocytes, Smooth Muscle/physiology
- Oxidative Stress/physiology
- Receptors, Adrenergic, alpha-1/physiology
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Affiliation(s)
- John C McGrath
- Autonomic Physiology Unit, Institute of Biomedical & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
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Somoza B, González C, Cachofeiro V, Lahera V, Fernández-Alfonso MS. Chronic l-arginine treatment reduces vascular smooth muscle cell hypertrophy through cell cycle modifications in spontaneously hypertensive rats. J Hypertens 2004; 22:751-8. [PMID: 15126917 DOI: 10.1097/00004872-200404000-00018] [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: 11/26/2022]
Abstract
OBJECTIVE To investigate the effect of long-term l-arginine supplementation on phenotype and proliferative status of vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) as well as the possible changes in nitric oxide (NO) availability. METHODS Male SHR, 22 weeks of age, received l-arginine (660 mg/kg per day) in their drinking water for 12 weeks. VSMCs from untreated (C-VSMC) and l-arginine-treated (l-Arg-VSMC) SHR were isolated from the common carotid artery, cultured and used until passage five. Size, protein content, cell proliferation and ploidy were evaluated in carotid VSMCs in culture, as well as the possible association of NO in these changes. RESULTS Relative cell size, total protein content per cell, and number of polyploid cells were significantly lower in l-Arg-VSMC compared to C-VSMC. Fetal calf serum stimulation (10% FCS) increased cell number only in l-Arg-VSMC. DNA synthesis, assessed by [H]methylthymidine incorporation after 10% FCS stimulation, was higher in l-Arg-VSMC than in C-VSMC. Cell cycle analysis revealed a significant increase of the number of l-Arg-VSMC at the G1 phase, together with a reduction at the G2 + M phase. In contrast, C-VSMC were arrested at the G2 + M phase of the cell cycle. Nitrite/nitrate levels, as well as intracellular cyclic guanosine monophosphate (cGMP) content, were significantly higher in l-Arg-VSMC. This was accompanied by enhanced inducible nitric oxide synthase (iNOS) expression and activity and a decreased constitutive nitric oxide synthase (cNOS) activity in these cells. CONCLUSIONS The results suggest that chronic treatment with l-arginine induces changes in VSMC size, ploidy and cell cycle. These changes are accompanied by iNOS induction and stimulation of the NO-cGMP pathway.
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Affiliation(s)
- Beatriz Somoza
- Departamento de Farmacología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
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26
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Abstract
Cigarette smoking as an addictive habit has accompanied human beings for more than 4 centuries. It is also one of the most potent and prevalent environmental health risks human beings are exposed to, and it is responsible for more than 1000 deaths each day in the United States. With recent research progress, it becomes clear that cigarette smoking can cause almost all major diseases prevalent today, such as cancer or heart disease. These detrimental effects are not only present in active smokers who choose the risk, but also to innocent bystanders, as passive smokers, who are exposed to cigarettes not-by-choice. While the cigarette-induced harm to human health is indiscriminate and severe, the degree of damage also varies from individual to individual. This intersubject variability in cigarette-induced pathologies is partly mediated by genetic variants of genes that may participate in detoxification process, eg, cytochrome P450 (CYP), cellular susceptibility to toxins, such as p53, or disease development. Through population studies, we have learned that certain CYP1A1 variants, such as Mspl polymorphism, may render the carriers more susceptible to cigarette-induced lung cancer or severe coronary atherosclerosis. The endothelial nitric oxide synthase intron 4 rare allele homozygotes are more likely to have myocardial infarction if they also smoke. In vitro experimental approach has further demonstrated that cigarettes may specifically regulate these genes in genotype-dependent fashion. While we still know little about genetic basis and molecular pathways for cigarette-induced pathological changes, understanding these mechanisms will be of great value in designing strategies to further reduce smoking in targeted populations, and to implement more effective measures in prevention and treatment of cigarette-induced diseases.
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Affiliation(s)
- Xing Li Wang
- Vascular Genetics Laboratory, Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, TX 78227, USA.
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Kantachuvesiri S, Fleming S, Peters J, Peters B, Brooker G, Lammie AG, McGrath I, Kotelevtsev Y, Mullins JJ. Controlled hypertension, a transgenic toggle switch reveals differential mechanisms underlying vascular disease. J Biol Chem 2001; 276:36727-33. [PMID: 11448960 DOI: 10.1074/jbc.m103296200] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A novel inbred rat model with inducible hypertension has been generated using a renin transgene under the transcriptional control of the cytochrome P450, Cyp1a1 promoter. The degree and duration of hypertension are regulated tightly by administration of the natural xenobiotic indole-3 carbinol and can be readily reversed. Induction experiments reveal distinct temporal and mechanistic responses to hypertensive injury in different vascular beds, which is indicative of differential susceptibility of organs to a hypertensive stimulus. The mesentery and heart exhibited the greatest sensitivity to damage, and the kidney showed an adaptive response prior to the development of malignant hypertensive injury. Quantitative analysis of morphological changes induced in mesenteric resistance arteries suggest eutrophic remodeling of the vessels. Kinetic evidence suggests that locally activated plasma prorenin may play a critical role in mediating vascular injury. This model will facilitate studies of the cellular and genetic mechanisms underlying vascular injury and repair and provide a basis for the identification of novel therapeutic targets for vascular disease.
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Affiliation(s)
- S Kantachuvesiri
- Molecular Physiology Laboratory, University of Edinburgh Medical School, Wilkie Building, Teviot Place, Edinburgh EH8 9AG, United Kingdom
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Tuttle JL, Nachreiner RD, Bhuller AS, Condict KW, Connors BA, Herring BP, Dalsing MC, Unthank JL. Shear level influences resistance artery remodeling: wall dimensions, cell density, and eNOS expression. Am J Physiol Heart Circ Physiol 2001; 281:H1380-9. [PMID: 11514310 DOI: 10.1152/ajpheart.2001.281.3.h1380] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The magnitude of shear stimulus has been shown to determine the level of growth factor expression in cell culture. However, little is known regarding what effect shear level has on specific arterial wall remodeling events in vivo. We have hypothesized that the rate of luminal diameter change and specific remodeling events within the arterial wall layers are dependent on shear level. Selective ligations were made to alter the number of microvascular perfusion units of mesenteric arteries within the same animal to approximately 50%, 200%, and 400% of control. Arterial blood flow and wall shear rate were correlated with the degree of alteration in perfusion units. Luminal diameters were decreased in 50% arteries by day 2 and increased approximately 17% and 33% respectively, in 200% and 400% arteries at day 7. The rate of diameter change was greatest in 50% and 400% arteries. Wall areas (medial +37%; intimal +18% at day 2) and cell densities (intimal +26%; adventitial +44% at day 2) were altered only in the 400% arteries. A positive correlation existed by day 2 between endothelial staining for endothelial nitric oxide synthase and shear level. The results demonstrate that shear level influences the rate of luminal expansion, specific remodeling events within each wall layer, and the degree of endothelial gene expression. A greater understanding of how shear level influences specific remodeling events within each wall layer should aid in the development of targeted therapies to manipulate the remodeling process in health and disease.
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Affiliation(s)
- J L Tuttle
- Department of Surgery, Indiana University Medical Center, Indianapolis, Indiana 46202, USA
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29
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Zhang Y, Stewart KG, Davidge ST. Endogenous estrogen mediates vascular reactivity and distensibility in pregnant rat mesenteric arteries. Am J Physiol Heart Circ Physiol 2001; 280:H956-61. [PMID: 11179035 DOI: 10.1152/ajpheart.2001.280.3.h956] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of estrogen in the maternal systemic cardiovascular adaptations during pregnancy is still controversial. Female Sprague-Dawley rats were implanted at day 14 of pregnancy with either a 50-mg tamoxifen pellet (estrogen receptor blocker, n = 10) or placebo pellet (n = 10). Virgin female rats were a nonpregnant control (n = 7). At days 20-22 of pregnancy, resistance-sized mesenteric arteries were mounted onto a dual-chamber arteriograph system. Pregnancy significantly blunted the pressor response to phenylephrine [measurement of the effective concentration that yielded 50% maximum response (EC(50)) values were 1.5 +/- 0.22 vs. 0.69 +/- 0.16 microM (P < 0.05)] and enhanced vasodilation to ACh [EC(50) = 1.13 +/- 2.53 vs. 3.13 +/- 6.04 nM (P < 0.05)] compared with nonpregnant rats. However, tamoxifen treatment during pregnancy reversed these effects. Inhibition of nitric oxide (NO) synthase with N(G)-monomethyl-L-arginine (250 microM) shifted only the responses of the placebo-treated pregnant group to both phenylephrine and ACh. Arterial distensibility in the placebo-treated pregnant group was also significantly increased (P < 0.05) compared with nonpregnant and tamoxifen-treated pregnant animals. In summary, endogenous estrogen during pregnancy increases NO-dependent modulation of vessel tone and arterial distensibility.
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Affiliation(s)
- Y Zhang
- Perinatal Research Centre, Department of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta T6G 2S2, Canada
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Zhang Y, Stewart KG, Davidge ST. Estrogen replacement reduces age-associated remodeling in rat mesenteric arteries. Hypertension 2000; 36:970-4. [PMID: 11116109 DOI: 10.1161/01.hyp.36.6.970] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Estrogen replacement therapy significantly decreases the incidence of cardiovascular disease in postmenopausal women. In aging, there is an increase in vascular stiffness along with a decrease in matrix metalloproteinase (MMP) activity. Our hypothesis was that estrogen replacement would increase MMPs and therefore reduce the vascular stiffness that is associated with aging. Female Sprague-Dawley rats were implanted with a placebo or 17ss-estradiol-containing pellet (0.5 mg/pellet, 60-day release) at 10 months of age (n=6, each). Six young rats (3 months old) were also studied. After a 2-month exposure to the pellet, mesenteric arteries were studied on a pressurized arteriograph system. Distensibility and wall thickness were measured in response to stepwise increases in intraluminal pressure in Ca(2+)-free physiological saline solution buffer with papaverine (10(-4) mol/L). In response to increasing pressure, aged placebo rats exhibited a significant decrease in distensibility compared with young rats (P<0.05) that was accompanied by an increase in wall thickness (P<0.05). Conversely, estrogen replacement increased distensibility and decreased wall thickness in aged rats (old estrogen-replaced versus old placebo, P<0.05). Zymography data indicated that MMP-2 activity decreased in aging but was increased by estrogen replacement. In summary, estrogen replacement in aging female rats reduces age-associated vascular remodeling.
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Affiliation(s)
- Y Zhang
- Departments of Obstetrics/Gynecology and Physiology, Perinatal Research Centre, University of Alberta, Edmonton, Canada
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Ceiler DL, De Mey JG. Chronic N(G)-nitro-L-arginine methyl ester treatment does not prevent flow-induced remodeling in mesenteric feed arteries and arcading arterioles. Arterioscler Thromb Vasc Biol 2000; 20:2057-63. [PMID: 10978249 DOI: 10.1161/01.atv.20.9.2057] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although endothelium-derived NO is an important mediator in acute flow-induced changes in arterial tone, the role of NO in chronic flow-induced changes in the resistance artery and arteriolar structure remains largely unresolved. We investigated the effects of chronic inhibition of NO synthase on arterial and arteriolar remodeling in a rat mesenteric model in which flow changes were induced. Alternating first-order mesenteric arteries were ligated to shunt blood flow through the intermittent patent arteries. Animals received no treatment (NT) or a continuous infusion of N:(G)-nitro-L-arginine methyl ester (L-NAME, 25 mg/kg SC per day). After 2 weeks, local in vivo blood flow and in vitro arterial pressure-diameter relationships were assessed, as were the in situ diameters of arcading arterioles. Medial cross-sectional areas (CSAs) were measured histologically. In both groups of animals, blood flow was significantly increased in patent arteries and decreased in ligated arteries compared with control vessels. Nonetheless, in L-NAME-treated rats, patent artery flow was increased to a lesser extent, although control flow was not significantly reduced (0.18+/-0.05 versus 0.26+/-0.05 mL/min). In NT rats, the diameter of patent arteries was significantly larger and the diameter of ligated arteries was significantly smaller than that of control arteries. CSAs displayed the same pattern of change (11. 9+/-0.6 x 10(3), 6.1+/-0.7 x 10(3), and 8.2+/-1.0 x 10(3) microm(2) for patent, ligated, and control arteries, respectively). Arterioles in the NT collateral pathway (218+/-15 microm) had diameters similar to control arteriole diameters (201+/-15 microm) but had a significantly larger CSA (6.2+/-0.6 x 10(3) versus 4.2+/-0.4 x 10(3) microm(2)). In L-NAME-treated rats, the flow-induced changes of the diameter and CSA in patent arteries, ligated arteries, and arcading arterioles mimicked those in NT rats. Nonetheless, control feed arteries (430+/-21 versus 497+/-16 microm) and arcading arterioles (156+/-21 microm) were significantly narrower after L-NAME treatment. Thus, chronic blockade of NO oxide synthase (1) tended to reduce arterial blood flow and resulted in inward remodeling of mesenteric arteries and arterioles and (2) did not prevent arterial and arteriolar remodeling in response to imposed changes in blood flow. Endothelium-derived mediators other than NO can play a major role in flow-induced arterial remodeling.
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Affiliation(s)
- D L Ceiler
- Department of Pharmacology and Toxicology, Cardiovascular Research Institute Maastricht (CARIM), Universiteit Maastricht, Maastricht, the Netherlands
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Kidd GA, Dobrucki LW, Brovkovych V, Bohr DF, Malinski T. Nitric oxide deficiency contributes to large cerebral infarct size. Hypertension 2000; 35:1111-8. [PMID: 10818073 DOI: 10.1161/01.hyp.35.5.1111] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The purpose of this study was to examine the role played by a deficit in nitric oxide (NO) in contributing to the large cerebral infarcts seen in hypertension. Cerebral infarction was produced in rats by occlusion of the middle cerebral artery (MCA). Studies were performed in Sprague-Dawley (SD) rats subjected to NO synthase blockade (N(G)-nitro-L-arginine [L-NNA], 20 mg x kg(-1) x d(-1) in drinking water) and in spontaneously hypertensive stroke-prone rats (SHRSP). NO released in the brain in response to MCA occlusion was monitored with a porphyrinic microsensor in Wistar-Kyoto rats. The increment in NO released with MCA occlusion was 1.31+/-0.05 micromol/L in L-NNA-treated rats, 1.25+/-0.04 micromol/L in SHRSP, 2. 24+/-0.07 micromol/L in control SD rats, and 2.25+/-0.06 micromol/L in Wistar-Kyoto rats (P<0.0001 for control versus the other groups). Infarct sizes in the L-NNA-treated and control SD rats were 8.50+/-0. 8% and 5.22+/-0.7% of the brain weights, respectively (P<0.05). The basilar arterial wall was significantly thicker in L-NNA-treated rats compared with their controls. We conclude that both the deficit in NO and the greater wall thickness contribute to the larger infarct size resulting from MCA occlusion in SHRSP and in L-NNA-treated rats compared with their respective controls.
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Affiliation(s)
- G A Kidd
- Department of Physiology, University of Michigan, Ann Arbor, USA
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33
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Abstract
The introduction of myographs was crucial for the study of structure and function of resistance arteries. The ability to support and maintain small blood vessels paved the way for true microscopic studies of the vascular cells. However, even after decades of study, we still do not know very much about the "normal" arrangement of smooth muscle cells in the vascular wall and how their distribution affects function. It was clearly time for the next technological step forward. We have shown here how the combination of myography and confocal microscopy creates a platform for the study of vascular structure at the cellular level and in 3D. In addition, the possibility of using live myograph-mounted vessels in combination with LSCM opens a new field of research to assess vascular remodeling from a physiological point of view and to study vascular function at a level not achieved by any other method at present. Now that the hardware is in place it is time to concentrate on the software and improve the methods of analysis. We have used 2D analysis of 3D data sets to describe differences in vascular structure and, at the same time, developed methods to semiautomate the process. The success of the 3D methods will ultimately depend on the reliability and accuracy of the analysis routines. There are still problems to overcome en route to finding a complete solution. However, we believe that the search for a robust fully (or semi-) automated method of 3D analysis will be more than worthwhile. We have defined vascular remodeling to include any changes in cellular arrangement or morphology. However, on a more subtle level, changes in receptors, enzymes, and proteins leading to altered functionality could also be regarded as remodeling. In that respect it may be interesting to map the distribution of the many receptors, channels, and proteins that regulate vascular growth, death, and function. Currently, there is a growing list of fluorescent ligands and antibodies that can be used in conjunction with confocal microscopy. It is possible that multiple stains could be used and imaged at different wavelengths with a view to constructing full 3D models of various structures and their colocalization. It is our belief that the confocal approach will prove to be a major tool in unraveling the complexities of cell-cell interactions and arrangements and will allow a better understanding of the process of vascular remodeling and function.
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Affiliation(s)
- S M Arribas
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Spain
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Arribas SM, Costa R, Salomone S, Morel N, Godfraind T, McGrath JC. Functional reduction and associated cellular rearrangement in SHRSP rat basilar arteries are affected by salt load and calcium antagonist treatment. J Cereb Blood Flow Metab 1999; 19:517-27. [PMID: 10326719 DOI: 10.1097/00004647-199905000-00006] [Citation(s) in RCA: 21] [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
The stroke-prone spontaneously hypertensive rat (SHRSP) is a strain with high incidence of cerebrovascular accidents increased by salt-rich diet and decreased by calcium-antagonist treatment. In the SHRSP rat basilar artery the authors have previously shown reduced contractility and altered structure including regions of smooth muscle cell (SMC) disorganization. The aims of this study have been to analyze (1) the morphology of these abnormal regions, (2) the structural modifications responsible for the reduced function, and (3) the effect of salt and calcium-antagonist treatment on vascular structure and function. Wistar Kyoto and SHRSP rats, untreated or treated from week 8 through 14 with 1% NaCl or 1% NaCl + 1 mg x kg(-1) x d(-1) lacidipine, were used. Function was studied with wire myography. Structure was analyzed in fixed intact arteries with confocal microscopy. Basilar arteries from SHRSP rat showed (1) reduced contractility, (2) discrete foci of SMC disarray with altered proportion of adventitia to SMC, and (3) decreased SMC and increased adventitial cell number. Arteries from salt-loaded SHRSP rats showed a higher degree of SMC disarray and further reduction in contractility. Lacidipine treatment of salt-loaded rats significantly improved structure and function. These data suggest that vascular remodeling can provide an explanation for the observed reduction in vascular contractility of SHRSP rat basilar arteries and might show light on the effects of salt load and calcium-channel blockers in life span and the incidence of cerebrovascular accidents in SHRSP rats.
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Affiliation(s)
- S M Arribas
- Autonomic Physiology Unit and CRI in Heart Failure, Institute of Biomedical and Life Sciences, University of Glasgow, United Kingdom
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