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Steward CJ, Hill M, Menzies C, Bailey SJ, Rahman M, Thake CD, Pugh CJA, Cullen T. Post exercise hot water immersion and hot water immersion in isolation enhance vascular, blood marker, and perceptual responses when compared to exercise alone. Scand J Med Sci Sports 2024; 34:e14600. [PMID: 38470997 DOI: 10.1111/sms.14600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 03/14/2024]
Abstract
Exercise and passive heating induce some similar vascular hemodynamic, circulating blood marker, and perceptual responses. However, it remains unknown whether post exercise hot water immersion can synergise exercise derived responses and if they differ from hot water immersion alone. This study investigated the acute responses to post moderate-intensity exercise hot water immersion (EX+HWI) when compared to exercise (EX+REST) and hot water immersion (HWI+HWI) alone. Sixteen physically inactive middle-aged adults (nine males and seven females) completed a randomized cross-over counterbalanced design. Each condition consisted of two 30-min bouts separated by 10 min of rest. Cycling was set at a power output equivalent to 50% V̇o2 peak . Water temperature was controlled at 40°C up to the mid sternum with arms not submerged. Venous blood samples and artery ultrasound scans were assessed at 0 (baseline), 30 (immediately post stressor one), 70 (immediately post stressor two), and 100 min (recovery). Additional physiological and perceptual measures were assessed at 10-min intervals. Brachial and superficial femoral artery shear rates were higher after EX+HWI and HWI+HWI when compared with EX+REST (p < 0.001). Plasma nitrite was higher immediately following EX+HWI and HWI+HWI than EX+REST (p < 0.01). Serum interleukin-6 was higher immediately after EX+HWI compared to EX+REST (p = 0.046). Serum cortisol was lower at 30 min in the HWI+HWI condition in contrast to EX+REST (p = 0.026). EX+HWI and HWI+HWI were more enjoyable than EX+REST (p < 0.05). Irrespective of whether hot water immersion proceeded exercise or heating, hot water immersion enhanced vascular and blood marker responses, while also being more enjoyable than exercise alone.
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Affiliation(s)
- Charles J Steward
- Centre for Physical Activity, Sport and Exercise Sciences, Coventry University, Coventry, UK
| | - Mathew Hill
- Centre for Physical Activity, Sport and Exercise Sciences, Coventry University, Coventry, UK
| | - Campbell Menzies
- Centre for Physical Activity, Sport and Exercise Sciences, Coventry University, Coventry, UK
| | - Stephen J Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Mushidur Rahman
- Centre for Physical Activity, Sport and Exercise Sciences, Coventry University, Coventry, UK
- Department of Cardiology, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, UK
| | - C Douglas Thake
- Centre for Physical Activity, Sport and Exercise Sciences, Coventry University, Coventry, UK
| | - Christopher J A Pugh
- Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, UK
| | - Tom Cullen
- Centre for Physical Activity, Sport and Exercise Sciences, Coventry University, Coventry, UK
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2
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Xu Z, Chen Y, Wang Y, Han W, Xu W, Liao X, Zhang T, Wang G. Matrix stiffness, endothelial dysfunction and atherosclerosis. Mol Biol Rep 2023; 50:7027-7041. [PMID: 37382775 DOI: 10.1007/s11033-023-08502-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 04/28/2023] [Indexed: 06/30/2023]
Abstract
Atherosclerosis (AS) is the leading cause of the human cardiovascular diseases (CVDs). Endothelial dysfunction promotes the monocytes infiltration and inflammation that participate fundamentally in atherogenesis. Endothelial cells (EC) have been recognized as mechanosensitive cells and have different responses to distinct mechanical stimuli. Emerging evidence shows matrix stiffness-mediated EC dysfunction plays a vital role in vascular disease, but the underlying mechanisms are not yet completely understood. This article aims to summarize the effect of matrix stiffness on the pro-atherosclerotic characteristics of EC including morphology, rigidity, biological behavior and function as well as the related mechanical signal. The review also discusses and compares the contribution of matrix stiffness-mediated phagocytosis of macrophages and EC to AS progression. These advances in our understanding of the relationship between matrix stiffness and EC dysfunction open the avenues to improve the prevention and treatment of now-ubiquitous atherosclerotic diseases.
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Affiliation(s)
- Zichen Xu
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400030, China
| | - Yi Chen
- Chongqing Engineering Laboratory of Nano/Micro Biomedical Detection, Chongqing Key Laboratory of Nano/Micro Composite Material and Device, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China
| | - Yi Wang
- College of Basic Medical Sciences, Chongqing Medical University, Chongqing, 400016, China
| | - Wenbo Han
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400030, China
| | - Wenfeng Xu
- Chongqing Engineering Laboratory of Nano/Micro Biomedical Detection, Chongqing Key Laboratory of Nano/Micro Composite Material and Device, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China
| | - Xiaoling Liao
- Chongqing Engineering Laboratory of Nano/Micro Biomedical Detection, Chongqing Key Laboratory of Nano/Micro Composite Material and Device, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China
| | - Tao Zhang
- Chongqing Engineering Laboratory of Nano/Micro Biomedical Detection, Chongqing Key Laboratory of Nano/Micro Composite Material and Device, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China.
| | - Guixue Wang
- Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400030, China.
- Bioengineering College of Chongqing University, NO.174, Shazheng Street, Shapingba District, Chongqing, 400030, PR China.
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Adams JA, Uryash A, Lopez JR. Non-Invasive Pulsatile Shear Stress Modifies Endothelial Activation; A Narrative Review. Biomedicines 2022; 10:biomedicines10123050. [PMID: 36551807 PMCID: PMC9775985 DOI: 10.3390/biomedicines10123050] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022] Open
Abstract
The monolayer of cells that line both the heart and the entire vasculature is the endothelial cell (EC). These cells respond to external and internal signals, producing a wide array of primary or secondary messengers involved in coagulation, vascular tone, inflammation, and cell-to-cell signaling. Endothelial cell activation is the process by which EC changes from a quiescent cell phenotype, which maintains cellular integrity, antithrombotic, and anti-inflammatory properties, to a phenotype that is prothrombotic, pro-inflammatory, and permeable, in addition to repair and leukocyte trafficking at the site of injury or infection. Pathological activation of EC leads to increased vascular permeability, thrombosis, and an uncontrolled inflammatory response that leads to endothelial dysfunction. This pathological activation can be observed during ischemia reperfusion injury (IRI) and sepsis. Shear stress (SS) and pulsatile shear stress (PSS) are produced by mechanical frictional forces of blood flow and contraction of the heart, respectively, and are well-known mechanical signals that affect EC function, morphology, and gene expression. PSS promotes EC homeostasis and cardiovascular health. The archetype of inducing PSS is exercise (i.e., jogging, which introduces pulsations to the body as a function of the foot striking the pavement), or mechanical devices which induce external pulsations to the body (Enhanced External Pulsation (EECP), Whole-body vibration (WBV), and Whole-body periodic acceleration (WBPA aka pGz)). The purpose of this narrative review is to focus on the aforementioned noninvasive methods to increase PSS, review how each of these modify specific diseases that have been shown to induce endothelial activation and microcirculatory dysfunction (Ischemia reperfusion injury-myocardial infarction and cardiac arrest and resuscitation), sepsis, and lipopolysaccharide-induced sepsis syndrome (LPS)), and review current evidence and insight into how each may modify endothelial activation and how these may be beneficial in the acute and chronic setting of endothelial activation and microvascular dysfunction.
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Affiliation(s)
- Jose A. Adams
- Division of Neonatology, Mount Sinai Medical Center, Miami Beach, FL 33140, USA
- Correspondence:
| | - Arkady Uryash
- Division of Neonatology, Mount Sinai Medical Center, Miami Beach, FL 33140, USA
| | - Jose R. Lopez
- Department of Research, Mount Sinai Medical Center, Miami Beach, FL 33140, USA
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4
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Abstract
In this review, we highlight recent studies from our group and others that have characterized the cardiovascular adjustments that occur after acute heat exposure. Special emphasis will be placed on underlying mechanisms and clinical implications. Finally, we postulate that these acute cardiovascular adjustments may predict the long-term adaptive response to chronic heat therapy.
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Affiliation(s)
- Steven A. Romero
- Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center
| | - Rauchelle E. Richey
- Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center
| | - Holden W. Hemingway
- Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center
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5
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Abello J, Raghavan S, Yien YY, Stratman AN. Peristaltic pumps adapted for laminar flow experiments enhance in vitro modeling of vascular cell behavior. J Biol Chem 2022; 298:102404. [PMID: 35988646 PMCID: PMC9508572 DOI: 10.1016/j.jbc.2022.102404] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/06/2022] Open
Abstract
Endothelial cells (ECs) are the primary cellular constituent of blood vessels that are in direct contact with hemodynamic forces over their lifetime. Throughout the body, vessels experience different blood flow patterns and rates that alter vascular architecture and cellular behavior. Because of the complexities of studying blood flow in an intact organism, particularly during development, the field has increasingly relied on in vitro modeling of blood flow as a powerful technique for studying hemodynamic-dependent signaling mechanisms in ECs. While commercial flow systems that recirculate fluids exist, many commercially available pumps are peristaltic and best model pulsatile flow conditions. However, there are many important situations in which ECs experience laminar flow conditions in vivo, such as along long straight stretches of the vasculature. To understand EC function under these contexts, it is important to be able to reproducibly model laminar flow conditions in vitro. Here, we outline a method to reliably adapt commercially available peristaltic pumps to study laminar flow conditions. Our proof-of-concept study focuses on 2D models but could be further adapted to 3D environments to better model in vivo scenarios, such as organ development. Our studies make significant inroads into solving technical challenges associated with flow modeling and allow us to conduct functional studies toward understanding the mechanistic role of shear forces on vascular architecture, cellular behavior, and remodeling in diverse physiological contexts.
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Affiliation(s)
- Javier Abello
- Department of Cell Biology and Physiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110
| | - Shreya Raghavan
- Department of Biomedical Engineering, Texas A&M University, College Station TX 77843
| | - Yvette Y Yien
- Pittsburgh Heart, Lung and Blood Vascular Medicine Institute and Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261
| | - Amber N Stratman
- Department of Cell Biology and Physiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110.
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Meki M, El-Baz A, Sethu P, Giridharan G. Effects of Pulsatility on Arterial Endothelial and Smooth Muscle Cells. Cells Tissues Organs 2022; 212:272-284. [PMID: 35344966 PMCID: PMC10782761 DOI: 10.1159/000524317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 03/16/2022] [Indexed: 01/04/2023] Open
Abstract
Continuous flow ventricular assist device (CFVAD) support in advanced heart failure patients causes diminished pulsatility, which has been associated with adverse events including gastrointestinal bleeding, end organ failure, and arteriovenous malformation. Recently, pulsatility augmentation by pump speed modulation has been proposed as a means to minimize adverse events. Pulsatility primarily affects endothelial and smooth muscle cells in the vasculature. To study the effects of pulsatility and pulse modulation using CFVADs, we have developed a microfluidic co-culture model with human aortic endothelial (ECs) and smooth muscle cells (SMCs) that can replicate physiologic pressures, flows, shear stresses, and cyclical stretch. The effects of pulsatility and pulse frequency on ECs and SMCs were evaluated during (1) normal pulsatile flow (120/80 mmHg, 60 bpm), (2) diminished pulsatility (98/92 mmHg, 60 bpm), and (3) low cyclical frequency (115/80 mmHg, 30 bpm). Shear stresses were estimated using computational fluid dynamics (CFD) simulations. While average shear stresses (4.2 dynes/cm2) and flows (10.1 mL/min) were similar, the peak shear stresses for normal pulsatile flow (16.9 dynes/cm2) and low cyclic frequency (19.5 dynes/cm2) were higher compared to diminished pulsatility (6.45 dynes/cm2). ECs and SMCs demonstrated significantly lower cell size with diminished pulsatility compared to normal pulsatile flow. Low cyclical frequency resulted in normalization of EC cell size but not SMCs. SMCs size was higher with low frequency condition compared to diminished pulsatility but did not normalize to normal pulsatility condition. These results may suggest that pressure amplitude augmentation may have a greater effect in normalizing ECs, while both pressure amplitude and frequency may be required to normalize SMCs morphology. The co-culture model may be an ideal platform to study flow modulation strategies.
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Affiliation(s)
- Moustafa Meki
- Bioengineering, University of Louisville, Louisville, KY, USA
| | - Ayman El-Baz
- Bioengineering, University of Louisville, Louisville, KY, USA
| | - Palanaippan Sethu
- Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
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Jiao Y, Zhang Y, Xiao Y, Xing Y, Cai Z, Wang C, Zhou Z, Feng Z, Gu Y. The crescendo pulse frequency of shear stress stimulates the endothelialization of bone marrow mesenchymal stem cells on the luminal surface of decellularized scaffold in the bioreactor. Bioengineered 2022; 13:7925-7938. [PMID: 35358008 PMCID: PMC9278976 DOI: 10.1080/21655979.2022.2039502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
A completely confluent endothelial cell (EC) monolayer is required to maintain proper vascular function in small diameter tissue-engineered vascular graft (TEVG). However, the most effective method for EC attachment to the luminal surface and formation of an entire endothelium layer that works in vitro remains a complicated challenge that requires urgent resolution. Although pulsatile flow has been shown to be better suited for the generation of functional endothelium, the optimal frequency setting is unknown. Several pulsatile flow frequencies were used to implant rat bone mesenchymal stem cells (MSC) into the lumen of decellularized porcine carotid arteries. The endothelium's integrity and cell activity were investigated in order to determine the best pulse frequency settings. The results showed that MSC were maximally preserved and exhibited maximal morphological changes with improved endothelialization performance in response to increased pulse stimulation frequency. Increased pulse frequency stimulation stimulates the expression of mechanoreceptor markers, cytoskeleton reorganization in the direction of blood flow, denser skeletal proteins fibronectin, and stronger intercellular connections when compared to constant pulse frequency stimulation. MSC eventually develops an intact endothelial layer with anti-thrombotic properties on the inner wall of the decellularized tubular lumen. Conclusion: The decellularized vessels retain the three-dimensional structure of the vasculature, have a surface topography suitable for MSC growth, and have good mechanical properties. By increasing the frequency of pulsed stimulation, MSC endothelialize the lumen of the decellularized vasculature. It is expected to have anti-thrombotic and anti-neointimal hyperplasia properties after implantation, ultimately improving the patency of TEVG.
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Affiliation(s)
- Yuhao Jiao
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yuanguo Zhang
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yonghao Xiao
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, China
| | - Yuehao Xing
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Zhiwen Cai
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Cong Wang
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Zhengtong Zhou
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Zengguo Feng
- School of Materials Science and Engineering, Beijing Institute of Technology, Beijing, China
| | - Yongquan Gu
- Department of Vascular Surgery, Xuanwu Hospital, Capital Medical University, Beijing, China
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8
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Roca F, Iacob M, Duflot T, Donnadieu N, Thill C, Bellien J, Joannides R. Adaptation of Arterial Wall Viscosity to the Short-Term Reduction of Heart Rate: Impact of Aging. J Am Heart Assoc 2022; 11:e023409. [PMID: 35112890 PMCID: PMC9245828 DOI: 10.1161/jaha.121.023409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Changes in arterial wall viscosity, which dissipates the energy stored within the arterial wall, may contribute to the beneficial effect of heart rate (HR) reduction on arterial stiffness and cardiovascular coupling. However, it has never been assessed in humans and could be altered by aging. We evaluated the effect of a selective HR-lowering agent on carotid arterial wall viscosity and the impact of aging on this effect. Methods and Results This randomized, placebo-controlled, double-blind, crossover study performed in 19 healthy volunteers evaluated the effects of ivabradine (5 mg BID, 1-week) on carotid arterial wall viscosity, mechanics, hemodynamics, and cardiovascular coupling. Arterial wall viscosity was evaluated by the area of the hysteresis loop of the pressure-lumen cross-sectional area relationship, representing the energy dissipated (WV), and by the relative viscosity (WV/WE), with WE representing the elastic energy stored. HR reduction by ivabradine increased WV and WE whereas WV/WE remained stable. In middle-aged subjects (n=11), baseline arterial stiffness and cardiovascular coupling were less favorable, and WE was similar but WV and therefore WV/WE were lower than in youth (n=8). HR reduction increased WV/WE in middle-aged but not in young subjects, owing to a larger increase in WV than WE. These results were supported by the age-related linear increase in WV/WE after HR reduction (P=0.009), explained by a linear increase in WV. Conclusion HR reduction increases arterial wall energy dissipation proportionally to the increase in WE, suggesting an adaptive process to bradycardia. This mechanism is altered during aging resulting in a larger than expected energy dissipation, the impact of which should be assessed. Registration URL: https://www.clinicaltrials.gov; Unique identifier: 2015/077/HP. URL: https://www. eudract.ema.europa.eu; Unique identifier: 2015-002060-17.
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Affiliation(s)
- Frédéric Roca
- Department of Pharmacology Rouen University Hospital Rouen France.,Clinical Investigation Center CIC-CRB 1404 Rouen France.,Normandie UniversityUNIROUENInserm U1096 Rouen France
| | - Michèle Iacob
- Department of Pharmacology Rouen University Hospital Rouen France.,Normandie UniversityUNIROUENInserm U1096 Rouen France
| | - Thomas Duflot
- Department of Pharmacology Rouen University Hospital Rouen France.,Normandie UniversityUNIROUENInserm U1096 Rouen France
| | | | | | - Jérémy Bellien
- Department of Pharmacology Rouen University Hospital Rouen France.,Clinical Investigation Center CIC-CRB 1404 Rouen France.,Normandie UniversityUNIROUENInserm U1096 Rouen France
| | - Robinson Joannides
- Department of Pharmacology Rouen University Hospital Rouen France.,Clinical Investigation Center CIC-CRB 1404 Rouen France.,Normandie UniversityUNIROUENInserm U1096 Rouen France
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Hemingway HW, Richey RE, Moore AM, Shokraeifard AM, Thomas GC, Olivencia-Yurvati AH, Romero SA. Shear stress induced by acute heat exposure is not obligatory to protect against endothelial ischemia-reperfusion injury in humans. J Appl Physiol (1985) 2022; 132:199-208. [PMID: 34941435 PMCID: PMC8759960 DOI: 10.1152/japplphysiol.00748.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Acute heat exposure protects against endothelial ischemia-reperfusion (I/R) injury in humans. However, the mechanism/s mediating this protective effect remain unclear. We tested the hypothesis that inhibiting the increase in shear stress induced by acute heat exposure would attenuate the protection of endothelial function following I/R injury. Nine (3 women) young healthy participants were studied under three experimental conditions: 1) thermoneutral control; 2) whole body heat exposure to increase body core temperature by 1.2°C; and 3) heat exposure + brachial artery compression to inhibit the temperature-dependent increase in shear stress. Endothelial function was assessed via brachial artery flow-mediated dilatation before (pre-I/R) and after (post-I/R) 20 min of arm ischemia followed by 20 min of reperfusion. Brachial artery shear rate was increased during heat exposure (681 ± 359 s-1), but not for thermoneutral control (140 ± 63 s-1; P < 0.01 vs. heat exposure) nor for heat + brachial artery compression (139 ± 60 s-1; P < 0.01 vs. heat exposure). Ischemia-reperfusion injury reduced flow-mediated dilatation following thermoneutral control (pre-I/R, 5.5 ± 2.9% vs. post-I/R, 3.8 ± 2.9%; P = 0.06), but was protected following heat exposure (pre-I/R, 5.8 ± 2.9% vs. post-I/R, 6.1 ± 2.9%; P = 0.5) and heat + arterial compression (pre-I/R, 4.4 ± 2.8% vs. post-I/R, 5.8 ± 2.8%; P = 0.1). Contrary to our hypothesis, our findings demonstrate that shear stress induced by acute heat exposure is not obligatory to protect against endothelial I/R injury in humans.NEW & NOTEWORTHY Acute heat exposure protects against endothelial ischemia-reperfusion injury in humans. However, the mechanism/s mediating this protective effect remain unclear. We utilized arterial compression to inhibit the temperature-dependent increase in brachial artery blood velocity that occurs during acute heat exposure to isolate the contribution of shear stress to the protection of endothelial function following ischemia-reperfusion injury. Our findings demonstrate that shear stress induced by acute heat exposure is not obligatory to protect against endothelial I/R injury.
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Affiliation(s)
- Holden W. Hemingway
- 1Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Rauchelle E. Richey
- 1Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Amy M. Moore
- 1Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Austin M. Shokraeifard
- 1Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Gabriel C. Thomas
- 1Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
| | - Albert H. Olivencia-Yurvati
- 1Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas,2Department of Surgery, University of North Texas Health Science Center, Fort Worth, Texas
| | - Steven A. Romero
- 1Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
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10
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Sakellariou XM, Papafaklis MI, Domouzoglou EM, Katsouras CS, Michalis LK, Naka KK. Exercise-mediated adaptations in vascular function and structure: Beneficial effects in coronary artery disease. World J Cardiol 2021; 13:399-415. [PMID: 34621486 PMCID: PMC8462042 DOI: 10.4330/wjc.v13.i9.399] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/30/2021] [Accepted: 07/21/2021] [Indexed: 02/06/2023] Open
Abstract
Exercise exerts direct effects on the vasculature via the impact of hemodynamic forces on the endothelium, thereby leading to functional and structural adaptations that lower cardiovascular risk. The patterns of blood flow and endothelial shear stress during exercise lead to atheroprotective hemodynamic stimuli on the endothelium and contribute to adaptations in vascular function and structure. The structural adaptations observed in arterial lumen dimensions after prolonged exercise supplant the need for acute functional vasodilatation in case of an increase in endothelial shear stress due to repeated exercise bouts. In contrast, wall thickness is affected by rather systemic factors, such as transmural pressure modulated during exercise by generalized changes in blood pressure. Several mechanisms have been proposed to explain the exercise-induced benefits in patients with coronary artery disease (CAD). They include decreased progression of coronary plaques in CAD, recruitment of collaterals, enhanced blood rheological properties, improvement of vascular smooth muscle cell and endothelial function, and coronary blood flow. This review describes how exercise via alterations in hemodynamic factors influences vascular function and structure which contributes to cardiovascular risk reduction, and highlights which mechanisms are involved in the positive effects of exercise on CAD.
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Affiliation(s)
- Xenofon M Sakellariou
- Michailideion Cardiac Centre, University of Ioannina, Ioannina 45100, Epirus, Greece
| | - Michail I Papafaklis
- Michailideion Cardiac Centre, University of Ioannina, Ioannina 45100, Epirus, Greece
- 2nd Department of Cardiology, University Hospital of Ioannina, Ioannina 45100, Epirus, Greece
| | - Eleni M Domouzoglou
- Michailideion Cardiac Centre, University of Ioannina, Ioannina 45100, Epirus, Greece
- Department of Pediatrics, University Hospital of Ioannina, Ioannina 45100, Epirus, Greece
| | - Christos S Katsouras
- Michailideion Cardiac Centre, University of Ioannina, Ioannina 45100, Epirus, Greece
- 2nd Department of Cardiology, University Hospital of Ioannina, Ioannina 45100, Epirus, Greece
| | - Lampros K Michalis
- Michailideion Cardiac Centre, University of Ioannina, Ioannina 45100, Epirus, Greece
- 2nd Department of Cardiology, University Hospital of Ioannina, Ioannina 45100, Epirus, Greece
| | - Katerina K Naka
- Michailideion Cardiac Centre, University of Ioannina, Ioannina 45100, Epirus, Greece
- 2nd Department of Cardiology, University Hospital of Ioannina, Ioannina 45100, Epirus, Greece
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11
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Sun Y, Zhang B, Xia L. Effect of low wall shear stress on the morphology of endothelial cells and its evaluation indicators. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 208:106082. [PMID: 34098346 DOI: 10.1016/j.cmpb.2021.106082] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/28/2021] [Indexed: 06/12/2023]
Abstract
OBJECTIVE This study is designed to explore the morphological changes of endothelial cells (ECs) under different levels of shear stress and find the effective evaluation indicators with in vivo and in vitro experiments. METHODS Human umbilical vein endothelial cells (HUVECs) and Sprague-Dawley rats were used to study the effect of different shear stress which applied by means of parallel plate-flow chamber and abdominal aorta banding model on the morphology of endothelial cells. Then, fluorescence images were acquired by means of a confocal laser-scanning microscope. Finally, Cell morphological indicators were extracted by SRAD-MCW computer image processing algorithm for quantitative analysis. RESULTS 1) The morphological changes of HUVECs were observed after exposure to shear stress for 6 h, the HUVECs were elongated and spindle-shaped. And the degree of cell deformability was different while the exposure time was different, then it became stable after 18 h. The HUVECs exposure to high shear stress (HSS) exhibited an ordered cell arrangement, while the HUVECs exposure to low shear stress (LSS) showed a disordered cell arrangement. 2) Traditional cell morphological indicators such as area, perimeter, long axis diameter, short axis diameter and orientation angle were not significantly different between the normal shear stress (NSS) group and the LSS group (P > 0.05), but the intercellular space characteristics such as the junction length per unit area and the triple points per unit area were significantly different (P < 0.05). CONCLUSION These results demonstrate that the size and duration of shear stress can affect the morphology and arrangement of endothelial cells. The commonly used evaluation indicators for studying the effect of shear stress on the morphology of endothelial cells, including area, perimeter, long axis diameter, short axis diameter and orientation angle, etc., had no significant statistical significance, while the intercellular space characteristics including the junction length per unit area and the triple points per unit area can be used as effective indicator to study the effect of shear stress on the morphology of endothelial cells.
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Affiliation(s)
- Yuqing Sun
- Department of Ultrasound in Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
| | - Bo Zhang
- Department of Ultrasound in Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
| | - Lianghua Xia
- Department of Ultrasound in Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
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12
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Haymet AB, Bartnikowski N, Wood ES, Vallely MP, McBride A, Yacoub S, Biering SB, Harris E, Suen JY, Fraser JF. Studying the Endothelial Glycocalyx in vitro: What Is Missing? Front Cardiovasc Med 2021; 8:647086. [PMID: 33937360 PMCID: PMC8079726 DOI: 10.3389/fcvm.2021.647086] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/19/2021] [Indexed: 12/16/2022] Open
Abstract
All human cells are coated by a surface layer of proteoglycans, glycosaminoglycans (GAGs) and plasma proteins, called the glycocalyx. The glycocalyx transmits shear stress to the cytoskeleton of endothelial cells, maintains a selective permeability barrier, and modulates adhesion of blood leukocytes and platelets. Major components of the glycocalyx, including syndecans, heparan sulfate, and hyaluronan, are shed from the endothelial surface layer during conditions including ischaemia and hypoxia, sepsis, atherosclerosis, diabetes, renal disease, and some viral infections. Studying mechanisms of glycocalyx damage in vivo can be challenging due to the complexity of immuno-inflammatory responses which are inextricably involved. Previously, both static as well as perfused in vitro models have studied the glycocalyx, and have reported either imaging data, assessment of barrier function, or interactions of blood components with the endothelial monolayer. To date, no model has simultaneously incorporated all these features at once, however such a model would arguably enhance the study of vasculopathic processes. This review compiles a series of current in vitro models described in the literature that have targeted the glycocalyx layer, their limitations, and potential opportunities for further developments in this field.
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Affiliation(s)
- Andrew B Haymet
- Critical Care Research Group, The Prince Charles Hospital, Chermside, QLD, Australia.,Faculty of Medicine, University of Queensland, St Lucia, QLD, Australia
| | - Nicole Bartnikowski
- Critical Care Research Group, The Prince Charles Hospital, Chermside, QLD, Australia.,Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia
| | - Emily S Wood
- Critical Care Research Group, The Prince Charles Hospital, Chermside, QLD, Australia.,Faculty of Medicine, University of Queensland, St Lucia, QLD, Australia
| | - Michael P Vallely
- Division of Cardiac Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, United States
| | - Angela McBride
- Department of Global Health and Infection, Brighton and Sussex Medical School, Brighton, United Kingdom.,Oxford University Clinical Research Unit, Wellcome Trust Africa Asia Programme, Ho Chi Minh City, Vietnam
| | - Sophie Yacoub
- Oxford University Clinical Research Unit, Wellcome Trust Africa Asia Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Scott B Biering
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Eva Harris
- Division of Infectious Diseases and Vaccinology, School of Public Health, University of California, Berkeley, Berkeley, CA, United States
| | - Jacky Y Suen
- Critical Care Research Group, The Prince Charles Hospital, Chermside, QLD, Australia.,Faculty of Medicine, University of Queensland, St Lucia, QLD, Australia
| | - John F Fraser
- Critical Care Research Group, The Prince Charles Hospital, Chermside, QLD, Australia.,Faculty of Medicine, University of Queensland, St Lucia, QLD, Australia
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13
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Brunt VE, Minson CT. Heat therapy: mechanistic underpinnings and applications to cardiovascular health. J Appl Physiol (1985) 2021; 130:1684-1704. [PMID: 33792402 DOI: 10.1152/japplphysiol.00141.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cardiovascular diseases (CVD) are the leading cause of death worldwide, and novel therapies are drastically needed to prevent or delay the onset of CVD to reduce the societal and healthcare burdens associated with these chronic diseases. One such therapy is "heat therapy," or chronic, repeated use of hot baths or saunas. Although using heat exposure to improve health is not a new concept, it has received renewed attention in recent years as a growing number of studies have demonstrated robust and widespread beneficial effects of heat therapy on cardiovascular health. Here, we review the existing literature, with particular focus on the molecular mechanisms that underscore the cardiovascular benefits of this practice.
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Affiliation(s)
- Vienna E Brunt
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado.,Department of Human Physiology, University of Oregon, Eugene, Oregon
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14
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Gao Y, Fan F, Jia J, Jiang Y, He D, Wu Z, Huo Y, Zhou J, Zhang Y. Heart Rate Predicts the Risk of New-Onset Peripheral Arterial Disease in a Community-Based Population in China. Ther Clin Risk Manag 2021; 17:267-274. [PMID: 33814912 PMCID: PMC8009540 DOI: 10.2147/tcrm.s304491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/17/2021] [Indexed: 11/23/2022] Open
Abstract
Introduction Elevated heart rate is linked with poor prognosis and has been shown to accelerate the progress of atherosclerosis. However, the association between heart rate and new-onset PAD is unknown. Methods A total of 3463 participants without PAD at baseline from a community-based cohort in Beijing were included and followed up for 2.3 years. PAD was defined as ankle–brachial index (ABI) ≤0.9. We used multivariate logistic regression models to investigate the association of heart rate and the risk of new-onset PAD. Results Participants were 56.67 ± 8.54 years old, and 36.12% were men. The baseline ABI was 1.11 ± 0.08, and the incidence of new-onset PAD was 2.97%. Multivariate regression models, adjusted for sex, age, risk factor of atherosclerosis, medications, and baseline ABI, showed that heart rate was significantly associated with incidence of PAD (odds ratio [OR] = 1.22, 95% confidence interval [CI]: 1.03–1.43, P = 0.020); every increase of 10 heart beats per minute (bpm) was associated with a 22% increase in the odds of developing new-onset PAD. Respondents in the higher-heart rate group (≥80 bpm) had an increased risk of new-onset PAD, compared with those in the lower-heart rate group (<80 bpm) (OR = 1.73, 95% CI: 1.14–2.63, P = 0.010). Subgroup analyses revealed no significant heterogeneity among the analyzed subgroups. Conclusion Elevated heart rate was independently associated with the risk of new-onset PAD in a community-based population in Beijing. Heart rate management should be considered for the purpose of PAD prevention.
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Affiliation(s)
- Yusi Gao
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
| | - Fangfang Fan
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
| | - Jia Jia
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
| | - Yimeng Jiang
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
| | - Danmei He
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
| | - Zhongli Wu
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
| | - Yong Huo
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
| | - Jing Zhou
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
| | - Yan Zhang
- Department of Cardiology, Peking University First Hospital, Beijing, People's Republic of China
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15
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Adams JA, Uryash A, Lopez JR, Sackner MA. The Endothelium as a Therapeutic Target in Diabetes: A Narrative Review and Perspective. Front Physiol 2021; 12:638491. [PMID: 33708143 PMCID: PMC7940370 DOI: 10.3389/fphys.2021.638491] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 01/29/2021] [Indexed: 12/18/2022] Open
Abstract
Diabetes has reached worldwide epidemic proportions, and threatens to be a significant economic burden to both patients and healthcare systems, and an important driver of cardiovascular mortality and morbidity. Improvement in lifestyle interventions (which includes increase in physical activity via exercise) can reduce diabetes and cardiovascular disease mortality and morbidity. Encouraging a population to increase physical activity and exercise is not a simple feat particularly in individuals with co-morbidities (obesity, heart disease, stroke, peripheral vascular disease, and those with cognitive and physical limitations). Translation of the physiological benefits of exercise within that vulnerable population would be an important step for improving physical activity goals and a stopgap measure to exercise. In large part many of the beneficial effects of exercise are due to the introduction of pulsatile shear stress (PSS) to the vascular endothelium. PSS is a well-known stimulus for endothelial homeostasis, and induction of a myriad of pathways which include vasoreactivity, paracrine/endocrine function, fibrinolysis, inflammation, barrier function, and vessel growth and formation. The endothelial cell mediates the balance between vasoconstriction and relaxation via the major vasodilator endothelial derived nitric oxide (eNO). eNO is critical for vasorelaxation, increasing blood flow, and an important signaling molecule that downregulates the inflammatory cascade. A salient feature of diabetes, is endothelial dysfunction which is characterized by a reduction of the bioavailability of vasodilators, particularly nitric oxide (NO). Cellular derangements in diabetes are also related to dysregulation in Ca2+ handling with increased intracellular Ca2+overload, and oxidative stress. PSS increases eNO bioavailability, reduces inflammatory phenotype, decreases intracellular Ca2+ overload, and increases antioxidant capacity. This narrative review and perspective will outline four methods to non-invasively increase PSS; Exercise (the prototype for increasing PSS), Enhanced External Counterpulsation (EECP), Whole Body Vibration (WBV), Passive Simulated Jogging and its predicate device Whole Body Periodic Acceleration, and will discuss current knowledge on their use in diabetes.
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Affiliation(s)
- Jose A Adams
- Division of Neonatology, Mount Sinai Medical Center, Miami Beach, FL, United States
| | - Arkady Uryash
- Division of Neonatology, Mount Sinai Medical Center, Miami Beach, FL, United States
| | - Jose R Lopez
- Department of Research, Mount Sinai Medical Center, Miami Beach, FL, United States
| | - Marvin A Sackner
- Department of Medicine, Mount Sinai Medical Center, Miami Beach, FL, United States
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16
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β-catenin promotes endothelial survival by regulating eNOS activity and flow-dependent anti-apoptotic gene expression. Cell Death Dis 2020; 11:493. [PMID: 32606304 PMCID: PMC7326989 DOI: 10.1038/s41419-020-2687-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 12/14/2022]
Abstract
Increased endothelial cell (EC) apoptosis is associated with the development of atherosclerotic plaques that develop predominantly at sites exposed to disturbed flow (DF). Strategies to promote EC survival may therefore represent a novel therapeutic approach in cardiovascular disease. Nitric oxide (NO) and β-catenin have both been shown to promote cell survival and they interact in ECs as we previously demonstrated. Here we investigated the physiological role of β-catenin as a mediator of NO-induced cell survival in ECs. We found that β-catenin depleted human umbilical vein ECs (HUVEC) stimulated with pharmacological activators of endothelial NO synthase (eNOS) showed a reduction in eNOS phosphorylation (Ser1177) as well as reduced intracellular cyclic guanosine monophosphate levels compared to control cells in static cultures. In addition, β-catenin depletion abrogated the protective effects of the NO donor, S-nitroso-N-acetylpenicillamine, during TNFα- and H2O2-induced apoptosis. Using an orbital shaker to generate shear stress, we confirmed eNOS and β-catenin interaction in HUVEC exposed to undisturbed flow and DF and showed that β-catenin depletion reduced eNOS phosphorylation. β-catenin depletion promoted apoptosis exclusively in HUVEC exposed to DF as did inhibition of soluble guanylate cyclase (sGC) or β-catenin transcriptional activity. The expression of the pro-survival genes, Bcl-2 and survivin was also reduced following inhibition of β-catenin transcriptional activity, as was the expression of eNOS. In conclusion, our data demonstrate that β-catenin is a positive regulator of eNOS activity and cell survival in human ECs. sGC activity and β-catenin-dependent transcription of Bcl-2, survivin, BIRC3 and eNOS are essential to maintain cell survival in ECs under DF.
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17
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Miura K, Kashima H, Morimoto M, Namura S, Yamaoka Endo M, Oue A, Fukuba Y. Effects of Unilateral Arm Warming or Cooling on the Modulation of Brachial Artery Shear Stress and Endothelial Function during Leg Exercise in Humans. J Atheroscler Thromb 2020; 28:271-282. [PMID: 32595193 PMCID: PMC8049146 DOI: 10.5551/jat.55731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: We examined the effect of modulating the shear stress (SS) profile using forearm warming and cooling on subsequent endothelial function in the brachial artery (BA) during exercise. Methods: Twelve healthy young subjects immersed their right forearm in water (15°C or 42°C) during a leg cycling exercise at 120–130 bpm for 60 min. The same exercise without water immersion served as a control. The BA diameter and blood velocity were simultaneously recorded using Doppler ultrasonography to evaluate the antegrade, retrograde, and mean shear rates (SRs, an estimate of SS) before, during, and after exercise. The endothelial function in the right BA was evaluated using flow-mediated dilation (FMD) (%) using two-dimensional high-resolution ultrasonography before (baseline) and 15 and 60 min after exercise. Results: During exercise, compared with the control trial, higher antegrade and mean SRs and lower retrograde SRs were observed in the warm trial; conversely, lower antegrade and mean SRs and higher retrograde SRs were observed in the cool trial. At 15 min postexercise, no significant change was observed in the FMD from baseline in the warm (Δ%FMD: +1.6%, tendency to increase; p = 0.08) and control trials (Δ %FMD: +1.1%). However, in the cool trial, the postexercise FMD at 60 min decreased from baseline (Δ%FMD: −2.7%) and was lower than that of the warm (Δ%FMD: +1.5%) and control (Δ%FMD: +1.2%) trials. Accumulated changes in each SR during and after exercise were significantly correlated with postexercise FMD changes. Conclusion: Modulation of shear profiles in the BA during exercise appears to be associated with subsequent endothelial function.
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Affiliation(s)
- Kohei Miura
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima.,Department of Health and Nutrition, Faculty of Health Sciences, University of Hiroshima Shudo
| | - Hideaki Kashima
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| | - Marina Morimoto
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| | - Saki Namura
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| | - Masako Yamaoka Endo
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
| | - Anna Oue
- Faculty of Food and Nutritional Sciences, Toyo University
| | - Yoshiyuki Fukuba
- Department of Exercise Science and Physiology, School of Health Sciences, Prefectural University of Hiroshima
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18
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Effects of heart rate reduction with ivabradine on vascular stiffness and endothelial function in chronic stable coronary artery disease. J Hypertens 2020; 37:1023-1031. [PMID: 30672832 DOI: 10.1097/hjh.0000000000001984] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Epidemiological and clinical studies have shown a relevant association between heart rate and cardiovascular mortality. Experimental studies identified vascular effects of heart rate reduction with the If channel inhibitor ivabradine. Therefore, the effects of heart rate reduction on endothelial function and indices of arterial stiffness were examined in patients with stable coronary artery disease in a prospective, placebo-controlled clinical crossover study. METHODS AND RESULTS Twenty-three patients (18 men and 5 women) with a resting heart rate (HR) of at least 70 beats per minute (bpm) and stable coronary artery disease were enrolled in this study. In a cross-over design, all patients were treated with ivabradine (Iva, 7.5 mg b.i.d.) and placebo for 6 months each. Iva reduced heart rate by 11.4 bpm (Iva 58.8 ± 8.2 bpm vs. placebo 70.2 ± 8.3 bpm, P < 0.0001). Augmentation index (AIx75), carotid-femoral pulse wave velocity (cfPWV) and central aortic blood pressure were measured using applanation tonometry (SphygmoCor). HRR by Iva increased AIx75 by 12.4% (Iva 24.3 ± 10.5% vs. placebo 21.3 ± 10.1%, P < 0.05) and reduced cfPWV by 14.1% (Iva 6.3 ± 1.7 m/s vs. placebo 7.3 ± 1.4 m/s, P < 0.01). Iva increased mean central blood pressure by 7.8% (Iva 107.5 ± 15.4 mmHg vs. placebo 99.1 ± 12.2 mmHg, P < 0.001). Endothelial function was determined measuring the flow-mediated vasodilation (FMD) of the brachial artery. HRR by Iva increased FMD by 18.5% (Iva 7.3 ± 2.2% vs. placebo 6.0 ± 2.0%, P < 0.001). Aortic distensibility was characterized by MRI. HRR by Iva increased aortic distensibility by 33.3% (Iva 0.003 ± 0.001/mmHg vs. placebo 0.002 ± 0.010/mmHg, P < 0.01) and circumferential cyclic strain by 37.1% (Iva 0.062 ± 0.027 vs. placebo 0.039 ± 0.018, P < 0.0001). CONCLUSION Heart rate reduction with Iva increased endothelium-dependent vasodilation and reduced arterial stiffness in patients with stable CAD. These findings corroborate and expand the results collected in experimental studies and indicate the importance of heart rate as a determinant of vascular function.
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19
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Van de Walle AB, McFetridge PS. Flow with variable pulse frequencies accelerates vascular recellularization and remodeling of a human bioscaffold. J Biomed Mater Res A 2020; 109:92-103. [PMID: 32441862 DOI: 10.1002/jbm.a.37009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 03/30/2020] [Accepted: 04/04/2020] [Indexed: 11/07/2022]
Abstract
Despite significant advances in vascular tissue engineering, the ideal graft has not yet been developed and autologous vessels remain the gold standard substitutes for small diameter bypass procedures. Here, we explore the use of a flow field with variable pulse frequencies over the regeneration of an ex vivo-derived human scaffold as vascular graft. Briefly, human umbilical veins were decellularized and used as scaffold for cellular repopulation with human smooth muscle cells (SMC) and endothelial cells (EC). Over graft development, the variable flow, which mimics the real-time cardiac output of an individual performing daily activities (e.g., resting vs. exercising), was implemented and compared to the commonly used constant pulse frequency. Results show marked differences on SMC and EC function, with changes at the molecular level reflecting on tissue scales. First, variable frequencies significantly increased SMC proliferation rate and glycosaminoglycan production. These results can be tied with the SMC gene expression that indicates a synthetic phenotype, with a significant downregulation of myosin heavy chain. Additionally and quite remarkably, the variable flow frequencies motivated the re-endothelialization of the grafts, with a quiescent-like structure observed after 10 days of conditioning, contrasting with the low surface coverage and unaligned EC observed under constant frequency (CF). Besides, the overall biomechanics of the generated grafts (conditioned with both pulsed and CFs) evidence a significant remodeling after 55 days of culture, depicted by high burst pressure and Young's modulus. These last results demonstrate the positive recellularization and remodeling of a human-derived scaffold toward an arterial vessel.
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Affiliation(s)
- Aurore B Van de Walle
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA.,Laboratoire Matière et Systèmes, Complexes MSC, UMR 7057, CNRS, University Paris Diderot, Paris Cedex 13, France
| | - Peter S McFetridge
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
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20
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Stupin M, Kibel A, Stupin A, Selthofer-Relatić K, Matić A, Mihalj M, Mihaljević Z, Jukić I, Drenjančević I. The Physiological Effect of n-3 Polyunsaturated Fatty Acids (n-3 PUFAs) Intake and Exercise on Hemorheology, Microvascular Function, and Physical Performance in Health and Cardiovascular Diseases; Is There an Interaction of Exercise and Dietary n-3 PUFA Intake? Front Physiol 2019; 10:1129. [PMID: 31543828 PMCID: PMC6728652 DOI: 10.3389/fphys.2019.01129] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/16/2019] [Indexed: 12/15/2022] Open
Abstract
Physical activity has a beneficial effect on systemic hemodynamics, physical strength, and cardiac function in cardiovascular (CV) patients. Potential beneficial effects of dietary intake of n-3 polyunsaturated fatty acids (n-3 PUFAs), such as α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid on hemorheology, vascular function, inflammation and potential to improve physical performance as well as other CV parameters are currently investigated. Recent meta-analysis suggests no effect of n-3 PUFA supplementation on CV function and outcomes of CV diseases. On the other hand, some studies support beneficial effects of n-3 PUFAs dietary intake on CV and muscular system, as well as on immune responses in healthy and in CV patients. Furthermore, the interaction of exercise and dietary n-3 PUFA intake is understudied. Supplementation of n-3 PUFAs has been shown to have antithrombotic effects (by decreasing blood viscosity, decreasing coagulation factor and PAI-1 levels and platelet aggregation/reactivity, enhancing fibrinolysis, but without effects on erythrocyte deformability). They decrease inflammation by decreasing IL-6, MCP-1, TNFα and hsCRP levels, expression of endothelial cell adhesion molecules and significantly affect blood composition of fatty acids. Treatment with n-3 PUFAs enhances brachial artery blood flow and conductance during exercise and enhances microvascular post-occlusive hyperemic response in healthy humans, however, the effects are unknown in cardiovascular patients. Supplementation of n-3 PUFAs may improve anaerobic endurance and may modulate oxygen consumption during intense exercise, may increase metabolic capacity, enhance endurance capacity delaying the onset of fatigue, and improving muscle hypertrophy and neuromuscular function in humans and animal models. In addition, n-3 PUFAs have anti-inflammatory and anti-nociceptive effects and may attenuate delayed-onset muscle soreness and muscle stiffness, and preserve joint mobility. On the other hand, effects of n-3 PUFAs were variably observed in men and women and they vary depending on dietary protocol, type of supplementation and type of sports activity undertaken, both in healthy and cardiovascular patients. In this review we will discuss the physiological effects of n-3 PUFA intake and exercise on hemorheology, microvascular function, immunomodulation and inflammation and physical performance in healthy persons and in cardiovascular diseases; elucidating if there is an interaction of exercise and diet.
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Affiliation(s)
- Marko Stupin
- Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Croatian National Scientific Center of Excellence for Personalized Health Care, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Department of Cardiovascular Diseases, Osijek University Hospital, Osijek, Croatia
| | - Aleksandar Kibel
- Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Croatian National Scientific Center of Excellence for Personalized Health Care, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Department of Cardiovascular Diseases, Osijek University Hospital, Osijek, Croatia
| | - Ana Stupin
- Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Croatian National Scientific Center of Excellence for Personalized Health Care, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Department of Pathophysiology, Physiology and Immunology, Faculty of Dental Medicine and Health Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Kristina Selthofer-Relatić
- Department of Cardiovascular Diseases, Osijek University Hospital, Osijek, Croatia.,Department of Internal Medicine, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Anita Matić
- Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Croatian National Scientific Center of Excellence for Personalized Health Care, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Martina Mihalj
- Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Croatian National Scientific Center of Excellence for Personalized Health Care, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Department of Dermatology, Osijek University Hospital, Osijek, Croatia
| | - Zrinka Mihaljević
- Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Croatian National Scientific Center of Excellence for Personalized Health Care, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Ivana Jukić
- Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Croatian National Scientific Center of Excellence for Personalized Health Care, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Ines Drenjančević
- Institute and Department of Physiology and Immunology, Faculty of Medicine Osijek, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.,Croatian National Scientific Center of Excellence for Personalized Health Care, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia
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Boeno FP, Farinha JB, Ramis TR, Macedo RCO, Rodrigues-Krause J, do Nascimento Queiroz J, Lopez P, Pinto RS, Reischak-Oliveira A. Effects of a Single Session of High- and Moderate-Intensity Resistance Exercise on Endothelial Function of Middle-Aged Sedentary Men. Front Physiol 2019; 10:777. [PMID: 31293446 PMCID: PMC6598115 DOI: 10.3389/fphys.2019.00777] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 06/04/2019] [Indexed: 01/30/2023] Open
Abstract
Regular resistance exercise is associated with metabolic, neuromuscular and cardiovascular adaptations which improve quality of life and health. However, sedentary subjects have shown acute impairments in endothelial function after high-intensity resistance exercise. The aim of this study was to evaluate endothelial function in sedentary middle-aged men after a single session of resistance exercise at different intensities. Eleven sedentary middle-aged men (40.1 ± 3.9 years; 27.3 ± 1.4 kg/m2) underwent three different conditions of assessment: (1) single knee extension exercise at moderate intensity (MI) [4 sets of 12 repetitions at 50% of one repetition maximum (1RM) for each leg], (2) single knee extension exercise at high intensity (HI) (4 sets of 8 repetitions at 80% of 1RM for each leg), (3) resting for the control condition (CON). Flow-mediated dilation (FMD) was assessed before, 30 and 60 min after exercise. Plasma concentrations of endothelin-1 (ET-1), nitrites and nitrates (NOx) and thiobarbituric acid reactive substances (TBARS) were measured before, immediately after and 60 min after exercise. Blood pressure (BP) was measured prior to the experimental protocols, and in the following times: immediately following, and 2, 5, 10, 15, 30, and 60 min after exertion. There was a significant improvement in FMD 30 min after MI condition (12.5 ± 4.10 vs. 17.2 ± 3.9%; p = 0.016). NOx levels were significantly higher immediately after MI (6.8 ± 3.3 vs. 12.6 ± 4.2 μM; p = 0.007) and there was a significant increase in the concentration of ET-1 immediately after HI (20.02 ± 2.2 vs. 25.4 ± 2.1 pg/mL; p = 0.004). However, there was no significant difference for BP (MI vs. HI) and TBARS among the experimental conditions. Resistance exercise performed at moderate intensity improved vasodilatation via increases on NOx levels and FMD in sedentary middle-aged men.
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Affiliation(s)
- Francesco Pinto Boeno
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Juliano Boufleur Farinha
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Thiago Rozales Ramis
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Rodrigo Cauduro Oliveira Macedo
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Josianne Rodrigues-Krause
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Jessica do Nascimento Queiroz
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Pedro Lopez
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Ronei Silveira Pinto
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Alvaro Reischak-Oliveira
- Program of Human Movement Sciences, Faculty of Physical Education, Physiotherapy and Dance, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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22
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Vitorino PR, Gomes KP, Ghazale PP, da Silva M, Mendes EP, Dos Santos FCA, Pansani AP, de Castro CH, Scorza FA, Colugnati DB. Coronary vasodilation impairment in pilocarpine model of epilepsy. Epilepsy Behav 2019; 90:7-10. [PMID: 30476810 DOI: 10.1016/j.yebeh.2018.10.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 10/23/2018] [Accepted: 10/27/2018] [Indexed: 01/27/2023]
Abstract
We investigated the coronary arteries reactivity alterations in rats with epilepsy induced by pilocarpine. To do so, male Wistar rats weighing between 250 g and 300 g were used. Status epilepticus (SE) was induced in rats using 385 mg/kg (i.p.) of pilocarpine. After 60 days from the first spontaneous seizure, rats were submitted to heart rate measurements and then, one day after, euthanized, and the heart was dissected and submitted to constant flow Langendorff approaches to evaluate coronary reactivity. Rats with epilepsy showed higher resting heart rate and impairment of coronary vasodilation induced by bradykinin. Endothelial nitric oxide synthase (eNOS) and superoxide dismutase (SOD) presented a reduced staining in coronary arteries, and eNOS expression was also reduced in the left ventricle of rats with epilepsy. Our findings demonstrated, for the first time, that epilepsy can cause impairment of coronary arteries reactivity, probably because of an endothelial dependent mechanism.
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Affiliation(s)
- Paula R Vitorino
- Department of Physiological Sciences, Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Federal University of Goiás, Goiânia, GO, Brazil
| | - Karina P Gomes
- Department of Physiological Sciences, Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Federal University of Goiás, Goiânia, GO, Brazil
| | - Poliana P Ghazale
- Department of Physiological Sciences, Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Federal University of Goiás, Goiânia, GO, Brazil
| | - Marielly da Silva
- Department of Physiological Sciences, Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Federal University of Goiás, Goiânia, GO, Brazil
| | - Elizabeth P Mendes
- Department of Physiological Sciences, Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Federal University of Goiás, Goiânia, GO, Brazil
| | - Fernanda C A Dos Santos
- Department of Histology, Embryology and Cell Biology, Laboratory of Histophysiology, Federal University of Goiás, Goiânia, GO, Brazil
| | - Aline P Pansani
- Department of Physiological Sciences, Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Federal University of Goiás, Goiânia, GO, Brazil
| | - Carlos H de Castro
- Department of Physiological Sciences, Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Federal University of Goiás, Goiânia, GO, Brazil
| | - Fulvio A Scorza
- Disciplina de Neurologia Experimental, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Diego B Colugnati
- Department of Physiological Sciences, Integrative Laboratory of Cardiovascular and Neurological Pathophysiology, Federal University of Goiás, Goiânia, GO, Brazil.
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23
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Xu L, Liang F, Zhao B, Wan J, Liu H. Influence of aging-induced flow waveform variation on hemodynamics in aneurysms present at the internal carotid artery: A computational model-based study. Comput Biol Med 2018; 101:51-60. [PMID: 30099239 DOI: 10.1016/j.compbiomed.2018.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/03/2018] [Accepted: 08/04/2018] [Indexed: 01/10/2023]
Abstract
The variation of blood flow waveform in the internal carotid artery (ICA) with age is a well-documented hemodynamic phenomenon, but little is known about how such variation affects the characteristics of blood flow in aneurysms present in the region. In the study, hemodynamic simulations were conducted for 26 ICA aneurysms, with flow waveforms measured in the ICAs of young and older adults being used respectively to set the inflow boundary conditions. Obtained results showed that replacing the young-adult flow waveform with the older-adult one led to little changes (<10%) in simulated time-averaged wall shear stress (WSS), transient maximum WSS, relative residence time and trans-aneurysm pressure loss coefficient, but resulted in a marked increase (32.36 ± 17.24%) in oscillatory shear index (OSI). Frequency-domain wave analysis revealed that the progressive enhancement of low-frequency harmonics dominated the observed flow waveform variation with age and was a major factor contributing to the increase in OSI. Cross-sectional comparisons among the aneurysms further revealed that the degree of increase in OSI correlated positively with some specific morphological features of aneurysm, such as aspect ratio and size ratio. In summary, the study demonstrates that the variation in flow waveform with age augments the oscillation of WSS in ICA aneurysms, which underlies the importance of setting patient-specific boundary conditions in hemodynamic studies on cerebral aneurysms, especially those involving long-term patient follow-up or cross-sectional comparison among patients of different ages.
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Affiliation(s)
- Lijian Xu
- School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China; Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE), Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Fuyou Liang
- School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China; Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration (CISSE), Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China; Sechenov University, Moscow, 119991, Russia.
| | - Bing Zhao
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Jieqing Wan
- Department of Neurosurgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200127, China
| | - Hao Liu
- Graduate School of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba-shi, Chiba, 2638522, Japan
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24
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Ghaffari M, Alaraj A, Du X, Zhou XJ, Charbel FT, Linninger AA. Quantification of near-wall hemodynamic risk factors in large-scale cerebral arterial trees. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2987. [PMID: 29601146 PMCID: PMC6043404 DOI: 10.1002/cnm.2987] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 05/18/2023]
Abstract
Detailed hemodynamic analysis of blood flow in pathological segments close to aneurysm and stenosis has provided physicians with invaluable information about the local flow patterns leading to vascular disease. However, these diseases have both local and global effects on the circulation of the blood within the cerebral tree. The aim of this paper is to demonstrate the importance of extending subject-specific hemodynamic simulations to the entire cerebral arterial tree with hundreds of bifurcations and vessels, as well as evaluate hemodynamic risk factors and waveform shape characteristics throughout the cerebral arterial trees. Angioarchitecture and in vivo blood flow measurement were acquired from healthy subjects and in cases with symptomatic intracranial aneurysm and stenosis. A global map of cerebral arterial blood flow distribution revealed regions of low to high hemodynamic risk that may significantly contribute to the development of intracranial aneurysms or atherosclerosis. Comparison of pre-intervention and post-intervention of pathological cases further shows large angular phase shift (~33.8°), and an augmentation of the peak-diastolic velocity. Hemodynamic indexes of waveform analysis revealed on average a 16.35% reduction in the pulsatility index after treatment from lesion site to downstream distal vessels. The lesion regions not only affect blood flow streamlines of the proximal sites but also generate pulse wave shift and disturbed flow in downstream vessels. This network effect necessitates the use of large-scale simulation to visualize both local and global effects of pathological lesions.
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Affiliation(s)
- Mahsa Ghaffari
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Ali Alaraj
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA
| | - Xinjian Du
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA
| | - Xiaohong Joe Zhou
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA
- Department of Radiology, University of Illinois at Chicago, Chicago, IL, USA
- Center for MR Research, University of Illinois at Chicago, Chicago, IL, USA
| | - Fady T. Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA
| | - Andreas A. Linninger
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA
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25
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Xu L, Liang F, Gu L, Liu H. Flow instability detected in ruptured versus unruptured cerebral aneurysms at the internal carotid artery. J Biomech 2018; 72:187-199. [PMID: 29602477 DOI: 10.1016/j.jbiomech.2018.03.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 03/03/2018] [Accepted: 03/06/2018] [Indexed: 11/30/2022]
Abstract
Flow instability has emerged as a new hemodynamic metric hypothesized to have potential value in assessing the rupture risk of cerebral aneurysms. However, diverse findings have been reported in the literature. In the present study, high-resolution hemodynamic simulations were performed retrospectively on 35 aneurysms (10 ruptured & 25 unruptured) located at the internal carotid artery (ICA). Simulated hemodynamic parameters were statistically compared between the ruptured and unruptured aneurysms, with emphasis on examining the correlation of flow instability with the status of aneurysm rupture. Pronounced flow instability was detected in 20% (2 out of 10) of the ruptured aneurysms, whereas in 44% (11 out of 25) of the unruptured aneurysms. Statistically, the flow instability metric (quantified by the temporally and spatially averaged fluctuating kinetic energy over the aneurysm sac) did not differ significantly between the ruptured and unruptured aneurysms. In contrast, low wall shear stress area (LSA) and pressure loss coefficient (PLC) exhibited significant correlations with the status of aneurysm rupture. In conclusion, the present study suggests that the presence of flow instability may not correlate closely with the status of aneurysm rupture, at least for ICA aneurysms. On the other hand, the retrospective nature of the study and the small sample size may have to some extent compromised the reliability of the conclusion, and therefore large-scale prospective studies would be needed to further address the issue.
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Affiliation(s)
- Lijian Xu
- School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Shanghai Jiao Tong University and Chiba University International Cooperative Research Centre (SJTU-CU ICRC), Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Fuyou Liang
- School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Shanghai Jiao Tong University and Chiba University International Cooperative Research Centre (SJTU-CU ICRC), Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
| | - Lixu Gu
- Shanghai Jiao Tong University and Chiba University International Cooperative Research Centre (SJTU-CU ICRC), Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Hao Liu
- School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Shanghai Jiao Tong University and Chiba University International Cooperative Research Centre (SJTU-CU ICRC), Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Graduate School of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba-shi, Chiba 2638522, Japan.
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26
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Bailey TG, Perissiou M, Windsor MT, Schulze K, Nam M, Magee R, Leicht AS, Green DJ, Greaves K, Golledge J, Askew CD. Effects of acute exercise on endothelial function in patients with abdominal aortic aneurysm. Am J Physiol Heart Circ Physiol 2017; 314:H19-H30. [PMID: 28939648 DOI: 10.1152/ajpheart.00344.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endothelial dysfunction is observed in patients with abdominal aortic aneurysm (AAA), who have increased risk of cardiovascular events and mortality. This study aimed to assess the acute effects of moderate- and higher-intensity exercise on endothelial function, as assessed by flow-mediated dilation (FMD), in AAA patients (74 ± 6 yr old, n = 22) and healthy adults (72 ± 5 yr old, n = 22). Participants undertook three randomized visits, including moderate-intensity continuous exercise [40% peak power output (PPO)], higher-intensity interval exercise (70% PPO), and a no-exercise control. Brachial artery FMD was assessed at baseline and at 10 and 60 min after each condition. Baseline FMD was lower [by 1.10% (95% confidence interval: 0.72-.81), P = 0.044] in AAA patients than in healthy adults. There were no group differences in FMD responses after each condition ( P = 0.397). FMD did not change after no-exercise control but increased by 1.21% (95% confidence interval: 0.69-1.73, P < 0.001) 10 min after moderate-intensity continuous exercise in both groups and returned to baseline after 60 min. Conversely, FMD decreased by 0.93% (95% confidence interval: 0.41-1.44, P < 0.001) 10 min after higher-intensity interval exercise in both groups and remained decreased after 60 min. We found that the acute response of endothelial function to exercise is intensity-dependent and similar between AAA patients and healthy adults. Our findings provide evidence that regular exercise may improve vascular function in AAA patients, as it does in healthy adults. Improved FMD after moderate-intensity exercise may provide short-term benefit. Whether the decrease in FMD after higher-intensity exercise represents an additional risk and/or a greater stimulus for vascular adaptation remains to be elucidated. NEW & NOTEWORTHY Abdominal aortic aneurysm patients have vascular dysfunction. We observed a short-term increase in vascular function after moderate-intensity exercise. Conversely, higher-intensity exercise induced a prolonged reduction in vascular function, which may be associated with both short-term increases in cardiovascular risk and signaling for longer-term vascular adaptation in abdominal aortic aneurysm patients.
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Affiliation(s)
- Tom G Bailey
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Maria Perissiou
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Mark T Windsor
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, Queensland, Australia
| | - Karl Schulze
- Sunshine Vascular Clinic, Buderim, Queensland, Australia
| | - Michael Nam
- Sunshine Coast University Hospital, Sunshine Coast Hospital and Health Service, Birtinya, Queensland, Australia
| | - Rebecca Magee
- Sunshine Coast University Hospital, Sunshine Coast Hospital and Health Service, Birtinya, Queensland, Australia
| | - Anthony S Leicht
- Sport and Exercise Science, James Cook University, Townville, Queensland, Australia
| | - Daniel J Green
- School of Sport Science, Exercise, and Health, University of Western Australia, Crawley, Western Australia, Australia.,Research Institute for Sport and Exercise Sciences, Liverpool John Moores University , Liverpool , United Kingdom
| | - Kim Greaves
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, Queensland, Australia.,Sunshine Coast University Hospital, Sunshine Coast Hospital and Health Service, Birtinya, Queensland, Australia
| | - Jonathan Golledge
- Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook University , Townsville, Queensland , Australia.,Department of Vascular and Endovascular Surgery, Townsville Hospital, Townsville, Queensland, Australia
| | - Christopher D Askew
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore, Queensland, Australia
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27
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Detection of frequency-dependent endothelial response to oscillatory shear stress using a microfluidic transcellular monitor. Sci Rep 2017; 7:10019. [PMID: 28855638 PMCID: PMC5577378 DOI: 10.1038/s41598-017-10636-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 08/10/2017] [Indexed: 02/06/2023] Open
Abstract
The endothelial microenvironment is critical in maintaining the health and function of the intimal layer in vasculature. In the context of cardiovascular disease (CVD), the vascular endothelium is the layer of initiation for the progression of atherosclerosis. While laminar blood flows are known to maintain endothelial homeostasis, disturbed flow conditions including those the endothelium experiences in the carotid artery are responsible for determining the fate of CVD progression. We present a microfluidic device designed to monitor the endothelium on two fronts: the real-time monitoring of the endothelial permeability using integrated electrodes and the end-point characterization of the endothelium through immunostaining. Our key findings demonstrate endothelial monolayer permeability and adhesion protein expression change in response to oscillatory shear stress frequency. These changes were found to be significant at certain frequencies, suggesting that a frequency threshold is needed to elicit an endothelial response. Our device made possible the real-time monitoring of changes in the endothelial monolayer and its end-point inspection through a design previously absent from the literature. This system may serve as a reliable research platform to investigate the mechanisms of various inflammatory complications of endothelial disorders and screen their possible therapeutics in a mechanistic and high-throughput manner.
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28
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Sarrami-Foroushani A, Lassila T, Frangi AF. Virtual endovascular treatment of intracranial aneurysms: models and uncertainty. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28488754 DOI: 10.1002/wsbm.1385] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/09/2017] [Accepted: 02/07/2017] [Indexed: 01/11/2023]
Abstract
Virtual endovascular treatment models (VETMs) have been developed with the view to aid interventional neuroradiologists and neurosurgeons to pre-operatively analyze the comparative efficacy and safety of endovascular treatments for intracranial aneurysms. Based on the current state of VETMs in aneurysm rupture risk stratification and in patient-specific prediction of treatment outcomes, we argue there is a need to go beyond personalized biomechanical flow modeling assuming deterministic parameters and error-free measurements. The mechanobiological effects associated with blood clot formation are important factors in therapeutic decision making and models of post-treatment intra-aneurysmal biology and biochemistry should be linked to the purely hemodynamic models to improve the predictive power of current VETMs. The influence of model and parameter uncertainties associated to each component of a VETM is, where feasible, quantified via a random-effects meta-analysis of the literature. This allows estimating the pooled effect size of these uncertainties on aneurysmal wall shear stress. From such meta-analyses, two main sources of uncertainty emerge where research efforts have so far been limited: (1) vascular wall distensibility, and (2) intra/intersubject systemic flow variations. In the future, we suggest that current deterministic computational simulations need to be extended with strategies for uncertainty mitigation, uncertainty exploration, and sensitivity reduction techniques. WIREs Syst Biol Med 2017, 9:e1385. doi: 10.1002/wsbm.1385 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ali Sarrami-Foroushani
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
| | - Toni Lassila
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
| | - Alejandro F Frangi
- Center for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), The University of Sheffield, Sheffield, UK
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29
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Bailey TG, Perissiou M, Windsor M, Russell F, Golledge J, Green DJ, Askew CD. Cardiorespiratory fitness modulates the acute flow-mediated dilation response following high-intensity but not moderate-intensity exercise in elderly men. J Appl Physiol (1985) 2017; 122:1238-1248. [DOI: 10.1152/japplphysiol.00935.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/30/2017] [Accepted: 02/11/2017] [Indexed: 01/05/2023] Open
Abstract
Impaired endothelial function is observed with aging and in those with low cardiorespiratory fitness (V̇o2peak). Improvements in endothelial function with exercise training are somewhat dependent on the intensity of exercise. While the acute stimulus for this improvement is not completely understood, it may, in part, be due to the flow-mediated dilation (FMD) response to acute exercise. We examined the hypothesis that exercise intensity alters the brachial (systemic) FMD response in elderly men and is modulated by V̇o2peak. Forty-seven elderly men were stratified into lower (V̇o2peak = 24.3 ± 2.9 ml·kg−1·min−1; n = 27) and higher fit groups (V̇o2peak = 35.4 ± 5.5 ml·kg−1·min−1; n = 20) after a test of cycling peak power output (PPO). In randomized order, participants undertook moderate-intensity continuous exercise (MICE; 40% PPO) or high-intensity interval cycling exercise (HIIE; 70% PPO) or no-exercise control. Brachial FMD was assessed at rest and 10 and 60 min after exercise. FMD increased after MICE in both groups {increase of 0.86% [95% confidence interval (CI), 0.17–1.56], P = 0.01} and normalized after 60 min. In the lower fit group, FMD was reduced after HIIE [reduction of 0.85% (95% CI, 0.12–1.58), P = 0.02] and remained decreased at 60 min. In the higher fit group, FMD was unchanged immediately after HIIE and increased after 60 min [increase of 1.52% (95% CI, 0.41–2.62), P < 0.01, which was correlated with V̇o2peak, r = 0.41; P < 0.01]. In the no-exercise control, FMD was reduced in both groups after 60 min ( P = 0.05). Exercise intensity alters the acute FMD response in elderly men and V̇o2peak modulates the FMD response following HIIE but not MICE. The sustained decrease in FMD in the lower fit group following HIIE may represent a signal for vascular adaptation or endothelial fatigue. NEW & NOTEWORTHY This study is the first to show that moderate-intensity continuous cycling exercise increased flow-mediated dilation (FMD) transiently before normalization of FMD after 1 h, irrespective of cardiorespiratory fitness level in elderly men. Interestingly, we show increased FMD after high-intensity cycling exercise in higher fit men, with a sustained reduction in FMD in lower fit men. The prolonged reduction in FMD after high-intensity cycling exercise may be associated with future vascular adaptation but may also reflect a period of increased cardiovascular risk in lower fit elderly men.
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Affiliation(s)
- Tom G. Bailey
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Queensland, Australia
| | - Maria Perissiou
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Queensland, Australia
| | - Mark Windsor
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Queensland, Australia
| | - Fraser Russell
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Queensland, Australia
| | - Jonathan Golledge
- Queensland Research Centre for Peripheral Vascular Disease, James Cook University and the Townsville Hospital, Townsville, Australia
| | - Daniel J. Green
- School of Sport Science, Exercise and Health, The University of Western Australia, Crawley, Australia; and
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Christopher D. Askew
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Queensland, Australia
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30
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Laosiripisan J, Parkhurst KL, Tanaka H. Associations of resting heart rate with endothelium-dependent vasodilation and shear rate. Clin Exp Hypertens 2017; 39:150-154. [PMID: 28287891 DOI: 10.1080/10641963.2016.1226890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Heart rate is an independent risk factor for cardiovascular disease and a hemodynamic factor that can modulate blood flow as it affects the frequency of shear stimuli acting on the arterial wall. However, the association between heart rate and endothelium-dependent vasodilation remains highly controversial. We determined the association between heart rate at rest and endothelium-dependent vasodilation in 98 apparently healthy adults (18-63 years). The mild and positive association between heart rate and flow-mediated dilation (FMD) was no longer significant when age and sex or baseline diameter were controlled for. The path analyses revealed that heart rate was not directly related to FMD but the association was indirectly mediated by shear rate, which was confirmed by a bias-corrected bootstrap 95% CIs (0.0157-0.1056). We concluded that even though heart rate and endothelium-dependent vasodilation were associated with shear rate, there was no independent relation between heart rate and FMD.
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Affiliation(s)
- Jitanan Laosiripisan
- a Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education , The University of Texas at Austin , Austin , Texas , USA
| | - Kristin L Parkhurst
- a Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education , The University of Texas at Austin , Austin , Texas , USA
| | - Hirofumi Tanaka
- a Cardiovascular Aging Research Laboratory, Department of Kinesiology and Health Education , The University of Texas at Austin , Austin , Texas , USA
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31
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Xu L, Gu L, Liu H. Exploring potential association between flow instability and rupture in patients with matched-pairs of ruptured-unruptured intracranial aneurysms. Biomed Eng Online 2016; 15:166. [PMID: 28155701 PMCID: PMC5260036 DOI: 10.1186/s12938-016-0277-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Background Patients with multiple intracranial aneurysms present a great challenge to the neurosurgeon, particularly when presenting with subarachnoid hemorrhage. Misjudgment may result in disastrous postoperative rebleeding from the untreated but true-ruptured lesion. Methods In this study, computational fluid dynamic simulations of two matched-pairs of ruptured–unruptured cerebral aneurysms were performed to investigate the potential association between flow instability and aneurysm rupture. Two pairs of cerebral aneurysms from two patients were located in the middle cerebral artery and the anterior communicating artery respectively. Results Our results demonstrated highly disturbed states of the blood flows in the ruptured aneurysms of the two patients with multiple aneurysms, which are characterized by remarked velocity and wall shear stress (WSS) fluctuations at late systole. The ruptured aneurysms exhibit obviously temporal intra-cycle WSS fluctuations rather than the unruptured aneurysms of the same patient. Cycle-to-cycle fluctuations are further observed in the ruptured aneurysms when the flow turns to decelerate. Conclusions The obvious differences observed between matched-pairs of ruptured–unruptured aneurysms imply that flow instability may be a potential source correlating to aneurysm rupture.
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Affiliation(s)
- Lijian Xu
- Shanghai Jiao Tong University and Chiba University International Cooperative Research Center (SJTU-CU ICRC), School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang district, Shanghai, People's Republic of China.,Graduate School of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba-shi, Chiba, Japan
| | - Lixu Gu
- Shanghai Jiao Tong University and Chiba University International Cooperative Research Center (SJTU-CU ICRC), School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang district, Shanghai, People's Republic of China.
| | - Hao Liu
- Shanghai Jiao Tong University and Chiba University International Cooperative Research Center (SJTU-CU ICRC), School of Biomedical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang district, Shanghai, People's Republic of China. .,Graduate School of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba-shi, Chiba, Japan.
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Sarrami-Foroushani A, Lassila T, Gooya A, Geers AJ, Frangi AF. Uncertainty quantification of wall shear stress in intracranial aneurysms using a data-driven statistical model of systemic blood flow variability. J Biomech 2016; 49:3815-3823. [PMID: 28573970 DOI: 10.1016/j.jbiomech.2016.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 09/06/2016] [Accepted: 10/09/2016] [Indexed: 01/17/2023]
Abstract
Adverse wall shear stress (WSS) patterns are known to play a key role in the localisation, formation, and progression of intracranial aneurysms (IAs). Complex region-specific and time-varying aneurysmal WSS patterns depend both on vascular morphology as well as on variable systemic flow conditions. Computational fluid dynamics (CFD) has been proposed for characterising WSS patterns in IAs; however, CFD simulations often rely on deterministic boundary conditions that are not representative of the actual variations in blood flow. We develop a data-driven statistical model of internal carotid artery (ICA) flow, which is used to generate a virtual population of waveforms used as inlet boundary conditions in CFD simulations. This allows the statistics of the resulting aneurysmal WSS distributions to be computed. It is observed that ICA waveform variations have limited influence on the time-averaged WSS (TAWSS) on the IA surface. In contrast, in regions where the flow is locally highly multidirectional, WSS directionality and harmonic content are strongly affected by the ICA flow waveform. As a consequence, we argue that the effect of blood flow variability should be explicitly considered in CFD-based IA rupture assessment to prevent confounding the conclusions.
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Affiliation(s)
- Ali Sarrami-Foroushani
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, The University of Sheffield, Pam Liversidge Building, Mappin Street, Sheffield S1 3JD, UK
| | - Toni Lassila
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, The University of Sheffield, Pam Liversidge Building, Mappin Street, Sheffield S1 3JD, UK
| | - Ali Gooya
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, The University of Sheffield, Pam Liversidge Building, Mappin Street, Sheffield S1 3JD, UK
| | - Arjan J Geers
- Centre for Cardiovascular Science, University of Edinburgh, UK
| | - Alejandro F Frangi
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, The University of Sheffield, Pam Liversidge Building, Mappin Street, Sheffield S1 3JD, UK.
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33
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Wall shear stress at the initiation site of cerebral aneurysms. Biomech Model Mechanobiol 2016; 16:97-115. [DOI: 10.1007/s10237-016-0804-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/24/2016] [Indexed: 11/30/2022]
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34
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Park WC, Seo I, Kim SH, Lee YJ, Ahn SV. Association between Resting Heart Rate and Inflammatory Markers (White Blood Cell Count and High-Sensitivity C-Reactive Protein) in Healthy Korean People. Korean J Fam Med 2016; 38:8-13. [PMID: 28197327 PMCID: PMC5305667 DOI: 10.4082/kjfm.2017.38.1.8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/02/2016] [Accepted: 05/19/2016] [Indexed: 01/30/2023] Open
Abstract
Background Inflammation is an important underlying mechanism in the pathogenesis of atherosclerosis, and an elevated resting heart rate underlies the process of atherosclerotic plaque formation. We hypothesized an association between resting heart rate and subclinical inflammation. Methods Resting heart rate was recorded at baseline in the KoGES-ARIRANG (Korean Genome and Epidemiology Study on Atherosclerosis Risk of Rural Areas in the Korean General Population) cohort study, and was then divided into quartiles. Subclinical inflammation was measured by white blood cell count and high-sensitivity C-reactive protein. We used progressively adjusted regression models with terms for muscle mass, body fat proportion, and adiponectin in the fully adjusted models. We examined inflammatory markers as both continuous and categorical variables, using the clinical cut point of the highest quartile of white blood cell count (≥7,900/mm3) and ≥3 mg/dL for high-sensitivity C-reactive protein. Results Participants had a mean age of 56.3±8.1 years and a mean resting heart rate of 71.4±10.7 beats/min; 39.1% were men. In a fully adjusted model, an increased resting heart rate was significantly associated with a higher white blood cell count and higher levels of high-sensitivity C-reactive protein in both continuous (P for trend <0.001) and categorical (P for trend <0.001) models. Conclusion An increased resting heart rate is associated with a higher level of subclinical inflammation among healthy Korean people.
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Affiliation(s)
- Woo-Chul Park
- Department of Family Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Inho Seo
- Department of Family Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Shin-Hye Kim
- Department of Family Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Yong-Jae Lee
- Department of Family Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Song Vogue Ahn
- Department of Preventive Medicine, Institute of Genomic Cohort, Yonsei University Wonju College of Medicine, Wonju, Korea
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35
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Franzoni M, Cattaneo I, Ene-Iordache B, Oldani A, Righettini P, Remuzzi A. Design of a cone-and-plate device for controlled realistic shear stress stimulation on endothelial cell monolayers. Cytotechnology 2016; 68:1885-96. [PMID: 26754843 DOI: 10.1007/s10616-015-9941-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 12/21/2015] [Indexed: 11/29/2022] Open
Abstract
Endothelial cells are constantly exposed to blood flow and the resulting frictional force, the wall shear stress, varies in magnitude and direction with time, depending on vasculature geometry. Previous studies have shown that the structure and function of endothelial cells, and ultimately of the vessel wall, are deeply affected by the nature of wall shear stress waveforms. To investigate the in vitro effects of these stimuli, we developed a compact, programmable, real-time operated system based on cone-and-plate geometry, that can be used within a standard cell incubator. To verify the capability to replicate realistic shear stress waveforms, we calculated both analytically and numerically to what extent the system is able to correctly deliver the stimuli defined by the user at plate level. Our results indicate that for radii greater than 25 mm, the shear stress is almost uniform and directly proportional to cone rotation velocity. We further established that using a threshold of 10 Hz of wall shear stress waveform frequency components, oscillating flow conditions can be reproduced on cell monolayer surface. Finally, we verified the capability of the system to perform long-term flow exposure experiments ensuring sterility and cell culture viability on human umbilical vein endothelial cells exposed to unidirectional and oscillating shear stress. In conclusion, the system we developed is a highly dynamic, easy to handle, and able to generate pulsatile and unsteady oscillating wall shear stress waveforms. This system can be used to investigate the effects of realistic stimulations on endothelial cells, similar to those exerted in vivo by blood flow.
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Affiliation(s)
- Marco Franzoni
- Department of Biomedical Engineering, IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Via Stezzano, 87, 24126, Bergamo, Italy
| | - Irene Cattaneo
- Department of Biomedical Engineering, IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Via Stezzano, 87, 24126, Bergamo, Italy
| | - Bogdan Ene-Iordache
- Department of Biomedical Engineering, IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Via Stezzano, 87, 24126, Bergamo, Italy
| | - Alberto Oldani
- Department of Management, Information and Production Engineering, University of Bergamo, Viale Marconi 4, 24144, Dalmine, BG, Italy
| | - Paolo Righettini
- Department of Management, Information and Production Engineering, University of Bergamo, Viale Marconi 4, 24144, Dalmine, BG, Italy
| | - Andrea Remuzzi
- Department of Biomedical Engineering, IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Via Stezzano, 87, 24126, Bergamo, Italy. .,Department of Management, Information and Production Engineering, University of Bergamo, Viale Marconi 4, 24144, Dalmine, BG, Italy.
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36
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De Wilde D, Trachet B, De Meyer GRY, Segers P. Shear Stress Metrics and Their Relation to Atherosclerosis: An In Vivo Follow-up Study in Atherosclerotic Mice. Ann Biomed Eng 2015; 44:2327-2338. [PMID: 26695938 DOI: 10.1007/s10439-015-1540-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/17/2015] [Indexed: 12/30/2022]
Abstract
It is generally accepted that low and oscillatory wall shear stress favors the initiation and development of atherosclerosis. However, a quantitative analysis of the association between shear stress metrics at baseline and lesion prevalence at a later stage is challenging to perform in vivo on a within-subject basis. In this study, we assessed carotid hemodynamics and derived hemodynamic wall parameters from subject-specific fluid-structure interaction simulations in the left and right carotid arteries of 4 ApoE(-/-) mice prior to disease development. We then applied a point-by-point quantitative association (surrogate sample data analysis) between various established and more recent shear related parameters and the extent of macrophage infiltration at a later stage. We conclude that, for the atherosclerotic murine carotid bifurcation, (i) there is an association between hemodynamics and macrophage infiltration; (ii) this correlation is most apparent when assessed at the level of the entire carotid bifurcation; (iii) the strongest spatial correlation between hemodynamics and atherosclerosis development was found for the time averaged wall shear stress (negative correlation) and the relative residence time (positive correlation); (iv) aggregating the data leads to an overestimation of the correlation.
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Affiliation(s)
- David De Wilde
- IBiTech-bioMMeda, iMinds Medical IT, Ghent University, Ghent, Belgium. .,bioMMeda, De Pintelaan185-blokB5, 9000, Ghent, Belgium.
| | - Bram Trachet
- IBiTech-bioMMeda, iMinds Medical IT, Ghent University, Ghent, Belgium.,Institute for Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | | | - Patrick Segers
- IBiTech-bioMMeda, iMinds Medical IT, Ghent University, Ghent, Belgium
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37
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Thijssen DHJ, Schreuder THA, Newcomer SW, Laughlin MH, Hopman MTE, Green DJ. Impact of 2-Weeks Continuous Increase in Retrograde Shear Stress on Brachial Artery Vasomotor Function in Young and Older Men. J Am Heart Assoc 2015; 4:e001968. [PMID: 26416875 PMCID: PMC4845130 DOI: 10.1161/jaha.115.001968] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 08/24/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Although acute elevation in retrograde shear rate (SR) impairs endothelial function, no previous study has explored the effect of prolonged elevation of retrograde SR on conduit artery vascular function. We examined the effect of 2-weeks elevation of retrograde SR on brachial artery endothelial function in young and in older men. METHODS AND RESULTS Thirteen healthy young (23±2 years) and 13 older men (61±5 years) were instructed to continuously wear a compression sleeve around the right forearm to chronically (2 weeks) elevate brachial artery retrograde SR in 1 arm. We assessed SR, diameter, and flow-mediated dilation in both the sleeve and contralateral control arms at baseline and after 30 minutes and 2 weeks of continuous sleeve application. The sleeve intervention increased retrograde SR after 30 minutes and 2 weeks in both young and older men (P=0.03 and 0.001, respectively). In young men, brachial artery flow-mediated dilation % was lower after 30 minutes and 2 weeks (P=0.004), while resting artery diameter was reduced after 2 weeks (P=0.005). The contralateral arm showed no change in retrograde SR or flow-mediated dilation % (P=0.32 and 0.26, respectively), but a decrease in diameter (P=0.035). In older men, flow-mediated dilation % and diameter did not change in either arm (all P>0.05). CONCLUSIONS Thirty-minute elevation in retrograde SR in young men caused impaired endothelial function, while 2-week exposure to elevated levels of retrograde SR was associated with a comparable decrease in endothelial function. Interestingly, these vascular changes were not present in older men, suggesting age-related vascular changes to elevation in retrograde SR.
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Affiliation(s)
- Dick H. J. Thijssen
- Department of PhysiologyRadboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Research Institute for Sport and Exercise ScienceLiverpool John Moores UniversityLiverpoolUnited Kingdom
| | - Tim H. A. Schreuder
- Department of PhysiologyRadboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | | | | | - Maria T. E. Hopman
- Department of PhysiologyRadboud Institute for Health SciencesRadboud University Medical CenterNijmegenThe Netherlands
| | - Daniel J. Green
- Research Institute for Sport and Exercise ScienceLiverpool John Moores UniversityLiverpoolUnited Kingdom
- School of Sport Science, Exercise and HealthThe University of Western AustraliaCrawleyWestern AustraliaAustralia
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38
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Ribeiro de Sousa D, Vallecilla C, Chodzynski K, Corredor Jerez R, Malaspinas O, Eker OF, Ouared R, Vanhamme L, Legrand A, Chopard B, Courbebaisse G, Zouaoui Boudjeltia K. Determination of a shear rate threshold for thrombus formation in intracranial aneurysms. J Neurointerv Surg 2015. [DOI: 10.1136/neurintsurg-2015-011737] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BackgroundParticular intra-aneurysmal blood flow conditions, created naturally by the growth of an aneurysm or induced artificially by implantation of a flow diverter stent (FDS), can potentiate intra-aneurysmal thrombosis. The aim of this study was to identify hemodynamic indicators, relevant to this process, which could be used as a prediction of the success of a preventive endovascular treatment.MethodA cross sectional study on 21 patients was carried out to investigate the possible association between intra-aneurysmal spontaneous thrombus volume and the dome to neck aspect ratio (AR) of the aneurysm. The mechanistic link between these two parameters was further investigated through a Fourier analysis of the intra-aneurysmal shear rate (SR) obtained by computational fluid dynamics (CFD). This analysis was first applied to 10 additional patients (4 with and 6 without spontaneous thrombosis) and later to 3 patients whose intracranial aneurysms only thrombosed after FDS implantation.ResultsThe cross sectional study revealed an association between intra-aneurysmal spontaneous thrombus volume and the AR of the aneurysm (R2=0.67, p<0.001). Fourier analysis revealed that in cases where thrombosis occurred, the SR harmonics 0, 1, and 2 were always less than 25/s, 10/s, and 5/s, respectively, and always greater than these values where spontaneous thrombosis was not observed.ConclusionsOur study suggests the existence of an SR threshold below which thrombosis will occur. Therefore, by analyzing the SR on patient specific data with CFD techniques, it may be potentially possible to predict whether or the intra-aneurysmal flow conditions, after FDS implantation, will become prothrombotic.
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Impact of handgrip exercise intensity on brachial artery flow-mediated dilation. Eur J Appl Physiol 2015; 115:1705-13. [PMID: 25805181 DOI: 10.1007/s00421-015-3157-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/17/2015] [Indexed: 01/22/2023]
Abstract
PURPOSE Previous studies that have examined the impact of exercise intensity on conduit artery endothelial function have involved large muscle group exercise which induces local and systemic effects. The aim of this study was to examine flow-mediated dilation (FMD) before and after incremental intensities of handgrip exercise (HE), to assess the role of local factors such as blood flow and shear rate on post-exercise brachial artery function. METHODS Eleven healthy men attended the laboratory on three occasions. Subjects undertook 30 min of handgrip exercise at three intensities (5, 10 or 15 % MVC). Brachial artery FMD, shear and blood flow patterns were examined before, immediately after and 60 min post exercise. RESULTS Handgrip exercise increased mean and antegrade shear rate (SR) and blood flow (BF) and reduced retrograde SR and BF (all P < 0.01). Exercise intensity was associated with a dose-dependent increase in both mean and antegrade BF and SR (interaction, P < 0.01). Post-hoc tests revealed that, whilst handgrip exercise did not immediately induce post-exercise changes, FMD was significantly higher 60 min post-exercise following the highest exercise intensity (5.9 ± 2.8-10.4 ± 5.8 %, P = 0.01). CONCLUSIONS Handgrip exercise leads to intensity-and time-dependent changes in conduit artery function, possibly mediated by local increases in shear, with improvement in function evident at 1 h post-exercise when performed at a higher intensity.
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40
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Fox BM, Brantley L, White C, Seigler N, Harris RA. Association beween resting heart rate, shear and flow-mediated dilation in healthy adults. Exp Physiol 2014; 99:1439-48. [PMID: 25037565 DOI: 10.1113/expphysiol.2014.080960] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Preclinical data have demonstrated that heart rate (HR) can directly impact vascular endothelial function, in part, through a shear-stress mechanism. This study sought to explore, in humans, the associations between resting heart rate and both shear and endothelial function assessed by flow-mediated dilation (FMD). The brachial artery FMD test was performed in 31 apparently healthy volunteers. Basal (B) and hyperaemic (H) shear were quantified in the following two ways using data from the FMD test: the traditional cumulative shear area under the curve up to peak dilation (Shearcum) method; and our novel method of shear summation (Shearsum), which accounts for HR by summing each individual cardiac cycle shear up to peak dilation. Data were grouped by tertiles based on resting HR as follows: low (LHR = 43-56 beats min(-1); n = 10); middle (MHR = 58-68 beats min(-1); n = 11); and high (HHR = 69-77 beats min(-1); n = 10). Within the LHR group, both B-Shearcum and H-Shearcum were significantly higher (P < 0.001) than B-Shearsum and H-Shearsum, respectively, whereas in the HHR group B-Shearcum and H-Shearcum were significantly lower (P < 0.001) than B-Shearsum and H-Shearsum, respectively. The FMD in the LHR group (8.8 ± 0.8%) was significantly greater than that in both the MHR group (5.5 ± 0.8%; P = 0.009) and the HHR group (5.9 ± 0.8%; P = 0.024). These findings demonstrate the existence of a relationship between heart rate and both shear and endothelial function in humans. Moreover, these findings have implications for considering heart rate as an important physiological variable when quantifying shear and performing the FMD test.
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Affiliation(s)
- Brandon M Fox
- Institute of Preventive and Public Health, Georgia Prevention Center, Georgia Regents University, Augusta, GA, UK
| | - Lucy Brantley
- Institute of Preventive and Public Health, Georgia Prevention Center, Georgia Regents University, Augusta, GA, UK
| | - Claire White
- Institute of Preventive and Public Health, Georgia Prevention Center, Georgia Regents University, Augusta, GA, UK
| | - Nichole Seigler
- Institute of Preventive and Public Health, Georgia Prevention Center, Georgia Regents University, Augusta, GA, UK
| | - Ryan A Harris
- Institute of Preventive and Public Health, Georgia Prevention Center, Georgia Regents University, Augusta, GA, UK Sport and Exercise Science Research Institute, University of Ulster, Jordanstown, County Antrim, UK
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41
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Significance, prognostic value and management of heart rate in hypertension. Arch Cardiovasc Dis 2014; 107:48-57. [DOI: 10.1016/j.acvd.2013.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/13/2013] [Indexed: 11/22/2022]
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Zhang J, Friedman MH. Adaptive response of vascular endothelial cells to an acute increase in shear stress frequency. Am J Physiol Heart Circ Physiol 2013; 305:H894-902. [PMID: 23851277 DOI: 10.1152/ajpheart.00174.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Local shear stress sensed by arterial endothelial cells is occasionally altered by changes in global hemodynamic parameters, e.g., heart rate and blood flow rate, as a result of normal physiological events, such as exercise. In a recently study (41), we demonstrated that during the adaptive response to increased shear magnitude, porcine endothelial cells exhibited an unique phenotype featuring a transient increase in permeability and the upregulation of a set of anti-inflammatory and antioxidative genes. In the present study, we characterize the adaptive response of these cells to an increase in shear frequency, another important hemodynamic parameter with implications in atherogenesis. Endothelial cells were preconditioned by a basal-level sinusoidal shear stress of 15 ± 15 dyn/cm(2) at 1 Hz, and the frequency was then elevated to 2 Hz. Endothelial permeability increased slowly after the frequency step-up, but the increase was relatively small. Using microarrays, we identified 37 genes that are sensitive to the frequency step-up. The acute increase in shear frequency upregulates a set of cell-cycle regulation and angiogenesis-related genes. The overall adaptive response to the increased frequency is distinctly different from that to a magnitude step-up. However, consistent with the previous study, our data support the notion that endothelial function during an adaptive response is different than that of fully adapted endothelial cells. Our studies may also provide insights into the beneficial effects of exercise on vascular health: transient increases in frequency may facilitate endothelial repair, whereas similar increases in shear magnitude may keep excessive inflammation and oxidative stress at bay.
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Affiliation(s)
- Ji Zhang
- Department of Biomedical Engineering, Duke University, Durham, North Carolina; and
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43
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Shalhub S, Zierler RE, Smith W, Olmsted K, Clowes AW. Vasospasm as a cause for claudication in athletes with external iliac artery endofibrosis. J Vasc Surg 2013; 58:105-11. [DOI: 10.1016/j.jvs.2012.12.060] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 10/27/2022]
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44
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Feaver RE, Gelfand BD, Blackman BR. Human haemodynamic frequency harmonics regulate the inflammatory phenotype of vascular endothelial cells. Nat Commun 2013; 4:1525. [PMID: 23443553 DOI: 10.1038/ncomms2530] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 01/21/2013] [Indexed: 01/14/2023] Open
Abstract
Haemodynamic variations are inherent to blood vessel geometries (such as bifurcations) and correlate with regional development of inflammation and atherosclerosis. However, the complex frequency spectrum characteristics from these haemodynamics have never been exploited to test whether frequency variations are critical determinants of endothelial inflammatory phenotype. Here we utilize an experimental Fourier transform analysis to systematically manipulate individual frequency harmonics from human carotid shear stress waveforms applied in vitro to human endothelial cells. The frequency spectrum, specifically the 0 th and 1st harmonics, is a significant regulator of inflammation, including NF-κB activity and downstream inflammatory phenotype. Further, a harmonic-based regression-model predicts eccentric NF-κB activity observed in the human internal carotid artery. Finally, short interfering RNA-knockdown of the mechanosensor PECAM-1 reverses frequency-dependent regulation of NF-κB activity. Thus, PECAM-1 may have a critical role in the endothelium's exquisite sensitivity to complex shear stress frequency harmonics and provide a mechanism for the focal development of vascular inflammation.
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Affiliation(s)
- Ryan E Feaver
- Department of Biomedical Engineering, University of Virginia, Box 800759, Health System, Charlottesville, Virginia 22908, USA
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45
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Frueh J, Maimari N, Homma T, Bovens SM, Pedrigi RM, Towhidi L, Krams R. Systems biology of the functional and dysfunctional endothelium. Cardiovasc Res 2013; 99:334-41. [PMID: 23650287 DOI: 10.1093/cvr/cvt108] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
This review provides an overview of the effect of blood flow on endothelial cell (EC) signalling pathways, applying microarray technologies to cultured cells, and in vivo studies of normal and atherosclerotic animals. It is found that in cultured ECs, 5-10% of genes are up- or down-regulated in response to fluid flow, whereas only 3-6% of genes are regulated by varying levels of fluid flow. Of all genes, 90% are regulated by the steady part of fluid flow and 10% by pulsatile components. The associated gene profiles show high variability from experiment to experiment depending on experimental conditions, and importantly, the bioinformatical methods used to analyse the data. Despite this high variability, the current data sets can be summarized with the concept of endothelial priming. In this concept, fluid flows confer protection by an up-regulation of anti-atherogenic, anti-thrombotic, and anti-inflammatory gene signatures. Consequently, predilection sites of atherosclerosis, which are associated with low-shear stress, confer low protection for atherosclerosis and are, therefore, more sensitive to high cholesterol levels. Recent studies in intact non-atherosclerotic animals confirmed these in vitro studies, and suggest that a spatial component might be present. Despite the large variability, a few signalling pathways were consistently present in the majority of studies. These were the MAPK, the nuclear factor-κB, and the endothelial nitric oxide synthase-NO pathways.
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Affiliation(s)
- Jennifer Frueh
- Department of Bioengineering, Royal School of Mines, Imperial College London, Exhibition Road, SW7 2AZ London, UK
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46
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Eberini I, Wait R, Calabresi L, Sensi C, Miller I, Gianazza E. A proteomic portrait of atherosclerosis. J Proteomics 2013; 82:92-112. [DOI: 10.1016/j.jprot.2013.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/11/2013] [Accepted: 02/13/2013] [Indexed: 01/11/2023]
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Yagi T, Sato A, Shinke M, Takahashi S, Tobe Y, Takao H, Murayama Y, Umezu M. Experimental insights into flow impingement in cerebral aneurysm by stereoscopic particle image velocimetry: transition from a laminar regime. J R Soc Interface 2013; 10:20121031. [PMID: 23427094 DOI: 10.1098/rsif.2012.1031] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner. The mid-systolic and late-diastolic flows with a Reynolds number of 450 and 230 were compared. The temporal and spatial variations of near-wall velocity at flow impingement delineated its inherent instability at a low Reynolds number. Wall shear stress (WSS) at that site exhibited a combination of temporal fluctuation and spatial divergence. The frequency range of fluctuation was found to exceed significantly that of the heart rate. The high-frequency-fluctuating WSS appeared only during mid-systole and disappeared during late diastole. These results suggested that the flow impingement induced a transition from a laminar regime. This study demonstrated that the hydrodynamic instability of shear layer could not be neglected even at a low Reynolds number. No assumption was found to justify treating the aneurysmal haemodynamics as a fully viscous laminar flow.
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Affiliation(s)
- Takanobu Yagi
- Center for Advanced Biomedical Sciences, Waseda University, Tokyo, Japan.
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Adaptation of endothelial cells to physiologically-modeled, variable shear stress. PLoS One 2013; 8:e57004. [PMID: 23457646 PMCID: PMC3573044 DOI: 10.1371/journal.pone.0057004] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 01/18/2013] [Indexed: 12/12/2022] Open
Abstract
Endothelial cell (EC) function is mediated by variable hemodynamic shear stress patterns at the vascular wall, where complex shear stress profiles directly correlate with blood flow conditions that vary temporally based on metabolic demand. The interactions of these more complex and variable shear fields with EC have not been represented in hemodynamic flow models. We hypothesized that EC exposed to pulsatile shear stress that changes in magnitude and duration, modeled directly from real-time physiological variations in heart rate, would elicit phenotypic changes as relevant to their critical roles in thrombosis, hemostasis, and inflammation. Here we designed a physiological flow (PF) model based on short-term temporal changes in blood flow observed in vivo and compared it to static culture and steady flow (SF) at a fixed pulse frequency of 1.3 Hz. Results show significant changes in gene regulation as a function of temporally variable flow, indicating a reduced wound phenotype more representative of quiescence. EC cultured under PF exhibited significantly higher endothelial nitric oxide synthase (eNOS) activity (PF: 176.0±11.9 nmol/105 EC; SF: 115.0±12.5 nmol/105 EC, p = 0.002) and lower TNF-a-induced HL-60 leukocyte adhesion (PF: 37±6 HL-60 cells/mm2; SF: 111±18 HL-60/mm2, p = 0.003) than cells cultured under SF which is consistent with a more quiescent anti-inflammatory and anti-thrombotic phenotype. In vitro models have become increasingly adept at mimicking natural physiology and in doing so have clarified the importance of both chemical and physical cues that drive cell function. These data illustrate that the variability in metabolic demand and subsequent changes in perfusion resulting in constantly variable shear stress plays a key role in EC function that has not previously been described.
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Jenkins NT, Martin JS, Laughlin MH, Padilla J. Exercise-induced Signals for Vascular Endothelial Adaptations: Implications for Cardiovascular Disease. CURRENT CARDIOVASCULAR RISK REPORTS 2012; 6:331-346. [PMID: 22844545 PMCID: PMC3404842 DOI: 10.1007/s12170-012-0241-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This article reviews recent advances in our understanding of hemodynamic signals, external/compressive forces, and circulating factors that mediate exercise training-induced vascular adaptations, with particular attention to the roles of these signals in prevention and treatment of endothelial dysfunction and cardiovascular (CV) diseases.
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Affiliation(s)
| | | | - M. Harold Laughlin
- Biomedical Sciences, University of Missouri, Columbia, MO
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO
- Medical Pharmacology and Physiology, University of Missouri, Columbia, MO
| | - Jaume Padilla
- Biomedical Sciences, University of Missouri, Columbia, MO
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Custodis F, Fries P, Müller A, Stamm C, Grube M, Kroemer HK, Böhm M, Laufs U. Heart rate reduction by ivabradine improves aortic compliance in apolipoprotein E-deficient mice. J Vasc Res 2012; 49:432-40. [PMID: 22759927 DOI: 10.1159/000339547] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 05/14/2012] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Impaired vascular compliance is associated with cardiovascular mortality. The effects of heart rate on vascular compliance are unclear. Therefore, we characterized effects of heart rate reduction (HRR) by I(f) current inhibition on aortic compliance and underlying molecular mechanisms in apolipoprotein E-deficient (ApoE(-)/(-)) mice. METHODS ApoE(-)/(-) mice fed a high-cholesterol diet and wild-type (WT) mice were treated with ivabradine (20 mg/kg/d) or vehicle for 6 weeks. Compliance of the ascending aorta was evaluated by MRI. RESULTS Ivabradine reduced heart rate by 113 ± 31 bpm (~19%) in WT mice and by 133 ± 6 bpm (~23%) in ApoE(-)/(-) mice. Compared to WT controls, ApoE(-)/(-) mice exhibited reduced distensibility and circumferential strain. HRR by ivabradine increased distensibility and circumferential strain in ApoE(-)/(-) mice but did not affect both parameters in WT mice. Ivabradine reduced aortic protein and mRNA expression of the angiotensin II type 1 (AT1) receptor and reduced rac1-GTPase activity in ApoE(-)/(-) mice. Moreover, membrane translocation of p47(phox) was inhibited. In ApoE(-)/(-) mice, HRR induced anti-inflammatory effects by reduction of aortic mRNA expression of IL-6, TNF-alpha and TGF-beta. CONCLUSION HRR by ivabradine improves vascular compliance in ApoE(-)/(-) mice. Contributing mechanisms include downregulation of the AT1 receptor, attenuation of oxidative stress and modulation of inflammatory cytokine expression.
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Affiliation(s)
- Florian Custodis
- Kliniken für Innere Medizin III, Kardiologie, Angiologie und Internistische Intensivmedizin, Universitätsklinikum des Saarlandes, Homburg/Saar, Germany.
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