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Flowmotion imaging analysis of spatiotemporal variations in skin microcirculatory perfusion. Microvasc Res 2023; 146:104456. [PMID: 36403668 DOI: 10.1016/j.mvr.2022.104456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/02/2022] [Accepted: 11/12/2022] [Indexed: 11/19/2022]
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2
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Tikhonova IV, Tankanag AV, Guseva IE, Grinevich AA. Analysis of interactions between cardiovascular oscillations for discrimination of early vascular disorders in arterial hypertension and type 2 diabetes. Biomed Signal Process Control 2023. [DOI: 10.1016/j.bspc.2022.104222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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3
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SenthilKumar G, Gutierrez-Huerta CA, Freed JK, Beyer AM, Fancher IS, LeBlanc AJ. New developments in translational microcirculatory research. Am J Physiol Heart Circ Physiol 2022; 323:H1167-H1175. [PMID: 36306213 PMCID: PMC9678417 DOI: 10.1152/ajpheart.00566.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/27/2022] [Accepted: 10/27/2022] [Indexed: 01/28/2023]
Abstract
Microvascular disease plays a critical role in systemic end-organ dysfunction, and treatment of microvascular pathologies may greatly reduce cardiovascular morbidity and mortality. The Call for Papers collection: New Developments in Translational Microcirculatory Research highlights key advances in our understanding of the role of microvessels in the development of chronic diseases as well as therapeutic strategies to enhance microvascular function. This Mini Review provides a concise summary of these advances and draws from other relevant research to provide the most up-to-date information on the influence of cutaneous, cerebrovascular, coronary, and peripheral microcirculation on the pathophysiology of obesity, hypertension, cardiovascular aging, peripheral artery disease, and cognitive impairment. In addition to these disease- and location-dependent research articles, this Call for Papers includes state-of-the-art reviews on coronary endothelial function and assessment of microvascular health in different organ systems, with an additional focus on establishing rigor and new advances in clinical trial design. These articles, combined with original research evaluating cellular, exosomal, pharmaceutical, exercise, heat, and dietary interventional therapies, establish the groundwork for translating microcirculatory research from bench to bedside. Although numerous studies in this collection are focused on human microcirculation, most used robust preclinical models to probe mechanisms of pathophysiology and interventional benefits. Future work focused on translating these findings to humans are necessary for finding clinical strategies to prevent and treat microvascular dysfunction.
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Affiliation(s)
- Gopika SenthilKumar
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Cristhian A Gutierrez-Huerta
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Julie K Freed
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Andreas M Beyer
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Ibra S Fancher
- Department of Kinesiology and Applied Physiology, College of Health Sciences, University of Delaware, Newark, Delaware
| | - Amanda Jo LeBlanc
- Department of Cardiovascular and Thoracic Surgery, School of Medicine, University of Louisville, Louisville, Kentucky
- Cardiovascular Innovation Institute, University of Louisville, Louisville, Kentucky
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4
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Jekell A, Kalani M, Kahan T. Skin microvascular reactivity and subendocardial viability ratio in relation to dyslipidemia and signs of insulin resistance in non-diabetic hypertensive patients. Microcirculation 2021; 29:e12747. [PMID: 34936176 DOI: 10.1111/micc.12747] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 11/11/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the influence of dyslipidemia and insulin resistance for the development of microvascular dysfunction in non-diabetic primary hypertension. METHODS Seventy-one patients with untreated primary hypertension were included. Skin microvascular reactivity was evaluated by laser Doppler fluxmetry with iontophoresis (acetylcholine, ACh and sodium nitroprusside, SNP) and heat-induced hyperemia. Myocardial microvascular function was estimated by the subendocardial viability ratio (SEVR) calculated from pulse wave analysis and applanation tonometry. Triglyceride x glucose (TyG index) and triglyceride/HDL cholesterol ratio were used as measurements of insulin resistance. RESULTS Skin microvascular dysfunction was associated with low HDL cholesterol, where Ach-mediated peak flux (r = .27, p = .025) and heat-induced peak flux (r = .29, p = .017) related to HDL cholesterol levels. ACh peak flux was inversely related to TG/HDL ratio (r = -.29, p = .016), while responses to local heating and SNP did not. SEVR did not relate to HDL and was unrelated to markers of insulin resistance. These findings were confirmed by multivariable analyses, including potential confounders. CONCLUSIONS Early microvascular dysfunction can be detected in non-diabetic hypertensive patients and is related to dyslipidemia and to signs of insulin resistance, thus predicting future cardiovascular risk.
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Affiliation(s)
- Andreas Jekell
- Division of Cardiovascular Medicine, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institute, Stockholm, Sweden
| | - Majid Kalani
- Division of Cardiovascular Medicine, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institute, Stockholm, Sweden
| | - Thomas Kahan
- Division of Cardiovascular Medicine, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institute, Stockholm, Sweden
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5
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Ranadive SM, Dillon GA, Mascone SE, Alexander LM. Vascular Health Triad in Humans With Hypertension-Not the Usual Suspects. Front Physiol 2021; 12:746278. [PMID: 34658930 PMCID: PMC8517241 DOI: 10.3389/fphys.2021.746278] [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: 07/23/2021] [Accepted: 08/25/2021] [Indexed: 11/13/2022] Open
Abstract
Hypertension (HTN) affects more than one-third of the US population and remains the top risk factor for the development of cardiovascular disease (CVD). Identifying the underlying mechanisms for developing HTN are of critical importance because the risk of developing CVD doubles with ∼20 mmHg increase in systolic blood pressure (BP). Endothelial dysfunction, especially in the resistance arteries, is the primary site for initiation of sub-clinical HTN. Furthermore, inflammation and reactive oxygen and nitrogen species (ROS/RNS) not only influence the endothelium independently, but also have a synergistic influence on each other. Together, the interplay between inflammation, ROS and vascular dysfunction is referred to as the vascular health triad, and affects BP regulation in humans. While the interplay of the vascular health triad is well established, new underlying mechanistic targets are under investigation, including: Inducible nitric oxide synthase, hydrogen peroxide, hydrogen sulfide, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and nuclear factor activated T cells. This review outlines the role of these unusual suspects in vascular health and function in humans. This review connects the dots using these unusual suspects underlying inflammation, ROS and vascular dysfunction especially in individuals at risk of or with diagnosed HTN based on novel studies performed in humans.
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Affiliation(s)
- Sushant M Ranadive
- Department of Kinesiology, University of Maryland, College Park, College Park, MD, United States
| | - Gabrielle A Dillon
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, United States.,Center for Healthy Aging, The Pennsylvania State University, University Park, PA, United States
| | - Sara E Mascone
- Department of Kinesiology, University of Maryland, College Park, College Park, MD, United States
| | - Lacy M Alexander
- Department of Kinesiology, The Pennsylvania State University, University Park, PA, United States.,Center for Healthy Aging, The Pennsylvania State University, University Park, PA, United States
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6
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Dillon GA, Stanhewicz AE, Serviente C, Greaney JL, Alexander LM. Hydrogen sulfide-dependent microvascular vasodilation is improved following chronic sulfhydryl-donating antihypertensive pharmacotherapy in adults with hypertension. Am J Physiol Heart Circ Physiol 2021; 321:H728-H734. [PMID: 34477463 DOI: 10.1152/ajpheart.00404.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Hypertension is characterized by systemic microvascular endothelial dysfunction, in part due to a functional absence of hydrogen sulfide (H2S)-mediated endothelium-dependent dilation. Treatment with a sulfhydryl-donating ACE inhibitor (SH-ACE inhibitor) improves endothelial function in preclinical models of hypertension. To date, no studies have directly assessed the effects of SH-ACE-inhibitor treatment on H2S-dependent vasodilation in humans with hypertension. We hypothesized that SH-ACE-inhibitor treatment would improve H2S-mediated endothelium-dependent vasodilation. Ten adults with hypertension [1 woman and 9 men; 56 ± 9 yr; systolic blood pressure (SBP): 141 ± 8.5 mmHg; diastolic blood pressure (DBP): 90.3 ± 6 mmHg] were treated (16 wk) with the SH-ACE-inhibitor captopril. Red blood cell flux (laser-Doppler flowmetry) was measured continuously during graded intradermal microdialysis perfusion of the endothelium-dependent agonist acetylcholine (ACh; 10-10 to 10-1 M) alone (control) and in combination with an inhibitor of enzymatic H2S production [10-3 M aminooxyacetate (AOAA)] preintervention and postintervention. Cutaneous vascular conductance (CVC; flux/mmHg) was calculated and normalized to the site-specific maximal CVC (0.028 M sodium nitroprusside and local heat to 43°C). Area under the curve was calculated using the trapezoid method. The 16-wk SH-ACE-inhibitor treatment resulted in a reduction of blood pressure (systolic BP: 129 ± 10 mmHg; diastolic BP: 81 ± 9 mmHg, both P < 0.05). Preintervention, inhibition of H2S production had no effect on ACh-induced vasodilation (316 ± 40 control vs. 322 ± 35 AU AOAA; P = 0.82). Captopril treatment improved ACh-induced vasodilation (316 ± 40 pre vs. 399 ± 55 AU post; P = 0.04) and increased the H2S-dependent component of ACh-induced vasodilation (pre: -6.6 ± 65.1 vs. post: 90.2 ± 148.3 AU, P = 0.04). These data suggest that SH-ACE-inhibitor antihypertensive treatment improves cutaneous microvascular endothelium-dependent vasodilation in adults with hypertension, in part via H2S-dependent mechanisms.NEW & NOTEWORTHY This is the first study to prospectively assess the effects of sulfhydryl antihypertensive treatment on microvascular endothelial function in adults with hypertension. Our data suggest that 16 wk of SH-ACE-inhibitor antihypertensive treatment improves cutaneous microvascular endothelium-dependent vasodilation in middle-aged adults with hypertension, in part via H2S-dependent mechanisms.
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Affiliation(s)
- Gabrielle A Dillon
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Center for Healthy Aging, The Pennsylvania State University, University Park, Pennsylvania
| | - Anna E Stanhewicz
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Department of Health and Human Physiology, The University of Iowa, Iowa City, Iowa
| | - Corinna Serviente
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Center for Healthy Aging, The Pennsylvania State University, University Park, Pennsylvania.,Institute for Applied Life Sciences, University of Massachusetts Amherst, Amherst, Massachusetts.,Department of Kinesiology, University of Massachusetts Amherst, Amherst, Massachusetts
| | - Jody L Greaney
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Department of Kinesiology, University of Texas Arlington, Arlington, Texas
| | - Lacy M Alexander
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, Pennsylvania.,Center for Healthy Aging, The Pennsylvania State University, University Park, Pennsylvania
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Liu JC, Hsu YP, Zhu JC, Hao WR, Yang TY, Sung LC, Kao PF, Hwang J, Hsiu H. Beat-to-beat and spectral analyses of the noninvasive radial pulse and laser-Doppler signals in patients with hypertension. Clin Hemorheol Microcirc 2021; 79:365-379. [PMID: 34180410 DOI: 10.3233/ch-201056] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study performed beat-to-beat and spectral analyses of 20-minute skin-surface laser-Doppler-flowmetry (LDF) and radial blood-pressure-waveform (BPW) signals in order to compare the blood-flow perfusion condition and regulatory mechanisms between essential-hypertension (EHT) patients and aged-matched control subjects. Beat-to-beat LDF analyses yielded the pulse width (PW), AC-to-DC ratio (AD), and their corresponding variability indices (coefficients of variation [CVs]). The relative energy contributions (RECs) of five characteristic frequency peaks (defined as FR1-FR5) were also calculated. Spectral BPW analysis obtained the amplitude proportion (Cn) and phase angle (Pn) of each harmonic component n. PW, AD, AD_CV, and REC of FR2 were significantly smaller in the EHT group than in the control group. Regarding BPW indices, C1, C2, C4, and C5 were significantly larger and P2-P8 were significantly smaller in EHT patients than in controls. The present results indicate that BPW and LDF indices can be used to evaluate the blood-flow perfusion efficiency and microcirculatory regulatory activities in EHT. Sex differences were found, with the effects being more prominent in female patients. These findings may be partly attributable to impairment of endothelial and neural regulatory functions. The present findings might aid the development of new noninvasive methods for reducing the risk of EHT-induced damage.
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Affiliation(s)
- Ju-Chi Liu
- Division of Cardiology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Taipei Heart Institute, Taipei Medical University, Taipei, Taiwan
| | - Yi-Ping Hsu
- Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Jia-Cheng Zhu
- Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
| | - Wen-Rui Hao
- Division of Cardiology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Tsung-Yeh Yang
- Division of Cardiology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Li-Chun Sung
- Division of Cardiology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Taipei Heart Institute, Taipei Medical University, Taipei, Taiwan
| | - Pai-Feng Kao
- Division of Cardiology, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Cardiology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Taipei Heart Institute, Taipei Medical University, Taipei, Taiwan
| | - Jaulang Hwang
- Department of Biochemistry and Molecular Cell Biology, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Hsin Hsiu
- Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan
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8
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Clough GF, Chipperfield AJ, Thanaj M, Scorletti E, Calder PC, Byrne CD. Dysregulated Neurovascular Control Underlies Declining Microvascular Functionality in People With Non-alcoholic Fatty Liver Disease (NAFLD) at Risk of Liver Fibrosis. Front Physiol 2020; 11:551. [PMID: 32581841 PMCID: PMC7283580 DOI: 10.3389/fphys.2020.00551] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/30/2020] [Indexed: 11/30/2022] Open
Abstract
Background/Aims Increasing evidence shows that non-alcoholic fatty liver disease (NAFLD) is associated with dysregulation of microvascular perfusion independently of established cardio-metabolic risk factors. We investigated whether hepatic manifestations of NAFLD such as liver fibrosis and liver fat are associated with microvascular hemodynamics through dysregulation of neurovascular control. Methods Microvascular dilator (post-occlusive reactive hyperemia) and sympathetically mediated constrictor (deep inspiratory breath-hold) responses were measured at the forearm and finger, respectively, using laser Doppler fluximetry. Non-linear complexity-based analysis was used to assess the information content and variability of the resting blood flux (BF) signals, attributable to oscillatory flow-motion activity, and over multiple sampling frequencies. Results Measurements were made in 189 adults (113 men) with NAFLD, with (n = 65) and without (n = 124) type 2 diabetes mellitus (T2DM), age = 50.9 ± 11.7 years (mean ± SD). Microvascular dilator and constrictor capacity were both negatively associated with age (r = −0.178, p = 0.014, and r = −0.201, p = 0.007, respectively) and enhanced liver fibrosis (ELF) score (r = −0.155, p = 0.038 and r = −0.418, p < 0.0001, respectively). There was no association with measures of liver fat, obesity or T2DM. Lempel-Ziv complexity (LZC) and sample entropy (SE) of the BF signal measured at the two skin sites were associated negatively with age (p < 0.01 and p < 0.001) and positively with ELF score (p < 0.05 and p < 0.0001). In individuals with an ELF score ≥7.8 the influence of both neurogenic and respiratory flow-motion activity on LZC was up-rated (p < 0.0001). Conclusion Altered microvascular network functionality occurs in adults with NAFLD suggesting a mechanistic role for dysregulated neurovascular control in individuals at risk of severe liver fibrosis.
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Affiliation(s)
- Geraldine F Clough
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Andrew J Chipperfield
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
| | - Marjola Thanaj
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
| | - Eleonora Scorletti
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.,National Institute for Health Research Southampton Biomedical Research Centre, University of Southampton, University Hospital Southampton National Health Service Foundation Trust, Southampton, United Kingdom.,Department of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Philip C Calder
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.,National Institute for Health Research Southampton Biomedical Research Centre, University of Southampton, University Hospital Southampton National Health Service Foundation Trust, Southampton, United Kingdom
| | - Christopher D Byrne
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.,National Institute for Health Research Southampton Biomedical Research Centre, University of Southampton, University Hospital Southampton National Health Service Foundation Trust, Southampton, United Kingdom
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9
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Katarzynska J, Cholewinski T, Sieron L, Marcinek A, Gebicki J. Flowmotion Monitored by Flow Mediated Skin Fluorescence (FMSF): A Tool for Characterization of Microcirculatory Status. Front Physiol 2020; 11:702. [PMID: 32636761 PMCID: PMC7317028 DOI: 10.3389/fphys.2020.00702] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/28/2020] [Indexed: 01/20/2023] Open
Abstract
Oscillations in the microcirculation, known as flowmotion, are a well-recognized characteristic of cutaneous blood flow. Since flowmotion reflects the microcirculatory status of the vascular system, which is very often impaired in many diseases and disorders, a quantitative assessment of skin flowmotion could potentially be used to screen for early symptoms of such conditions. In this study, skin flowmotion was monitored using the Flow Mediated Skin Fluorescence (FMSF) technique. The flowmotion parameter was used for quantitative assessment of basal flowmotion both at rest (FM) and during reperfusion [FM(R)] following the post-occlusive reactive hyperemia (PORH). The study population was composed of healthy volunteers between the ages of 30 and 72 (n = 75). The FM parameter showed an inverse dependence relative to age, while the FM(R) parameter was inversely correlated to blood pressure. The FM(R) parameter reflects the strong effect of hypoxia on flowmotion, which is mainly due to increased myogenic activity in the vessels. The FMSF technique appears to be uniquely suited for the analysis of basal flowmotion and the hypoxia response, and may be used for the characterization of microcirculatory status.
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Affiliation(s)
| | | | | | - Andrzej Marcinek
- Angionica Ltd., Lodz, Poland
- Institute of Applied Radiation Chemistry, Lodz University of Technology, Lodz, Poland
| | - Jerzy Gebicki
- Angionica Ltd., Lodz, Poland
- Institute of Applied Radiation Chemistry, Lodz University of Technology, Lodz, Poland
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10
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Wong BJ, Turner CG, Miller JT, Walker DC, Sebeh Y, Hayat MJ, Otis JS, Quyyumi AA. Sensory nerve-mediated and nitric oxide-dependent cutaneous vasodilation in normotensive and prehypertensive non-Hispanic blacks and whites. Am J Physiol Heart Circ Physiol 2020; 319:H271-H281. [PMID: 32559139 DOI: 10.1152/ajpheart.00177.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The purpose of this study was to investigate the effect of race and subclinical elevations in blood pressure (i.e., prehypertension) on cutaneous sensory nerve-mediated and nitric oxide (NO)-dependent vasodilation. We recruited participants who self-identified as either non-Hispanic black (n = 16) or non-Hispanic white (n = 16). Within each group, participants were subdivided as either normotensive (n = 8 per group) or prehypertensive (n = 8 per group). Each participant was instrumented with four intradermal microdialysis fibers: 1) control (lactated Ringer's), 2) 5% lidocaine (sensory nerve inhibition), 3) 20 mM Nω-nitro-l-arginine methyl ester (l-NAME) (NO synthase inhibition), and 4) lidocaine + l-NAME. Skin blood flow was assessed via laser-Doppler flowmetry, and each site underwent local heating from 33°C to 39°C. At the plateau, 20 mM l-NAME were infused at control and lidocaine sites to quantify NO-dependent vasodilation. Maximal vasodilation was induced via 54 mM sodium nitroprusside and local heating to 43°C. Data are means ± SD. Sensory nerve-mediated cutaneous vasodilation was reduced in prehypertensive non-Hispanic white (34 ± 7%) and both non-Hispanic black groups (normotensive, 20 ± 9%, prehypertensive, 24 ± 15%) relative to normotensive non-Hispanic whites (54 ± 12%). NO-dependent vasodilation was also reduced in prehypertensive non-Hispanic white (41 ± 7%) and both non-Hispanic black groups (normotensive, 44 ± 7%, prehypertensive, 19 ± 7%) relative to normotensive non-Hispanic whites (60 ± 11%). The decrease in NO-dependent vasodilation in prehypertensive non-Hispanic blacks was further reduced relative to all other groups. These data suggest subclinical increases in blood pressure adversely affect sensory-mediated and NO-dependent vasodilation in both non-Hispanic blacks and whites.NEW & NOTEWORTHY Overt hypertension is known to reduce cutaneous sensory nerve-mediated and nitric oxide (NO)-dependent vasodilation, but the effect of subclinical increases in blood pressure (i.e., prehypertension) is unknown. The combined effect of race and prehypertension is also unknown. In this study, we found that prehypertension reduces cutaneous sensory nerve-mediated and NO-dependent vasodilation in both non-Hispanic white and black populations, with the greatest reductions observed in prehypertensive non-Hispanic blacks.
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Affiliation(s)
- Brett J Wong
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Casey G Turner
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - James T Miller
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Demetria C Walker
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Yesser Sebeh
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Matthew J Hayat
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Jeffrey S Otis
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Arshed A Quyyumi
- Emory Clinical Cardiovascular Research Institute, School of Medicine, Emory University, Atlanta, Georgia
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11
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Low DA, Jones H, Cable NT, Alexander LM, Kenney WL. Historical reviews of the assessment of human cardiovascular function: interrogation and understanding of the control of skin blood flow. Eur J Appl Physiol 2019; 120:1-16. [PMID: 31776694 PMCID: PMC6969866 DOI: 10.1007/s00421-019-04246-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/19/2019] [Indexed: 02/06/2023]
Abstract
Several techniques exist for the determination of skin blood flow that have historically been used in the investigation of thermoregulatory control of skin blood flow, and more recently, in clinical assessments or as an index of global vascular function. Skin blood flow measurement techniques differ in their methodology and their strengths and limitations. To examine the historical development of techniques for assessing skin blood flow by describing the origin, basic principles, and important aspects of each procedure and to provide recommendations for best practise. Venous occlusion plethysmography was one of the earliest techniques to intermittently index a limb’s skin blood flow under conditions in which local muscle blood flow does not change. The introduction of laser Doppler flowmetry provided a method that continuously records an index of skin blood flow (red cell flux) (albeit from a relatively small skin area) that requires normalisation due to high site-to-site variability. The subsequent development of laser Doppler and laser speckle imaging techniques allows the mapping of skin blood flow from larger surface areas and the visualisation of capillary filling from the dermal plexus in two dimensions. The use of iontophoresis or intradermal microdialysis in conjunction with laser Doppler methods allows for the local delivery of pharmacological agents to interrogate the local and neural control of skin blood flow. The recent development of optical coherence tomography promises further advances in assessment of the skin circulation via three-dimensional imaging of the skin microvasculature for quantification of vessel diameter and vessel recruitment.
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Affiliation(s)
- David A Low
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK.
| | - Helen Jones
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - N Tim Cable
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Liverpool, UK
| | - Lacy M Alexander
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA
| | - W Larry Kenney
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, PA, USA
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12
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Hodges GJ, Cheung SS. Noninvasive assessment of increases in microvascular endothelial function following repeated bouts of hyperaemia. Microvasc Res 2019; 128:103929. [PMID: 31676308 DOI: 10.1016/j.mvr.2019.103929] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/07/2019] [Accepted: 09/16/2019] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Spectral analyses of laser-Doppler signal can delineate underlying mechanisms in response to pharmacological agents and in cross-sectional studies of healthy and clinical populations. We tested whether spectral analyses can detect acute changes in endothelial function in response to a 6-week intervention of repeated bouts of hyperaemia. METHODS Eleven males performed forearm occlusion (5 s with 10 s rest) for 30 min, 5 times/week for 6 weeks on one arm; the other was an untreated control. Skin blood flow was measured using laser-Doppler fluxmetry (LDF), and endothelial function was assessed with and without nitric oxide (NO) synthase-inhibition with L-NAME in response to local heating (42 °C and 44 °C) and acetylcholine. A wavelet transform was used for spectral analysis of frequency intervals associated with physiological functions. RESULTS Basal measures were all unaffected by the hyperaemia intervention (all P > 0.05). In response to local skin heating to 42 °C, the 6 weeks hyperaemia intervention increased LDF, endothelial NO-independent and NO-dependent activity (all P ≤ 0.038). In response to peak local heating (44 °C) endothelial NO-independent and NO-dependent activity increased (both P ≤ 0.01); however, LDF did not (P > 0.2). In response to acetylcholine, LDF, endothelial NO-independent and NO-dependent activity all increased (all P ≤ 0.003) post-intervention. CONCLUSIONS Spectral analysis appears sufficiently sensitive to measure changes over time in cutaneous endothelial activity that are consistent with standard physiological (local heating) and pharmacological (acetylcholine) interventions of assessing cutaneous endothelial function, and may be useful not only in research but also clinical diagnosis and treatment.
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Affiliation(s)
- Gary J Hodges
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Stephen S Cheung
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.
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13
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Silva H, Ferreira HA, da Silva HP, Monteiro Rodrigues L. The Venoarteriolar Reflex Significantly Reduces Contralateral Perfusion as Part of the Lower Limb Circulatory Homeostasis in vivo. Front Physiol 2018; 9:1123. [PMID: 30174614 PMCID: PMC6107688 DOI: 10.3389/fphys.2018.01123] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/27/2018] [Indexed: 12/31/2022] Open
Abstract
Perfusion at microvascular level involves the contribution of both local and central regulators, under a complex vascular signaling frame. The venoarteriolar reflex (VAR) is one of such regulatory responses, of particular relevance in the lower limb to prevent edema. Although known for quite some time, many of the complex interactions involving all of these regulatory mechanisms still need clarification. Our objective was to look deeper into VAR through modern photoplethymography (PPG). Twelve healthy subjects (both sexes, 26.0 ± 5.0 y.o.) were enrolled in this study after informed written consent. Subjects were submitted to a leg lowering maneuver while lying supine to evoke the VAR, involving three phases-10 min baseline register, both legs extended, 10 min challenge, with one randomly chosen leg (test) pending 50 cm below heart level, while the contralateral (control) remained in place, and 10 minutes recovery, resuming the initial position. PPG signals were collected from both feet and treated by the wavelet transform (WT) revealing six spectral bands in frequency intervals comprising the cardiac [1.6-0.7 Hz], respiratory [0.4-0.26 Hz], myogenic [0.26-0.1 Hz], neurogenic/sympathetic [0.1-0.045 Hz], endothelial NO-dependent (NOd) [0.045-0.015 Hz], and NO-independent (NOi) [0.015-0.007 Hz] activities. For the first time, this approach revealed that, with VAR, perfusion significantly decreased in both limbs, although the change was more pronounced in the test foot. Here, a significant decrease in myogenic, neurogenic and NOd, were noted, while the control foot recorded a decrease in neurogenic and an increase in NOd. These results confirm the utility of WT spectral analysis for flowmotion. Further, it strongly suggests that VAR results from a complex cooperation between local myogenic-endothelial responses, where a central neurogenic reflex might also be involved.
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Affiliation(s)
- Henrique Silva
- Research Center for Biosciences and Health Technologies, Universidade Lusófona's CBiOS, Lisbon, Portugal
- Pharmacological Sciences Department, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
| | - Hugo A. Ferreira
- Faculty of Sciences, Institute of Biophysics and Biomedical Engineering, Universidade de Lisboa, Lisbon, Portugal
| | - Hugo P. da Silva
- IT - Instituto de Telecomunicações, Lisbon, Portugal
- School of Technology, Polytechnic Institute of Setúbal, Setúbal, Portugal
| | - L. Monteiro Rodrigues
- Research Center for Biosciences and Health Technologies, Universidade Lusófona's CBiOS, Lisbon, Portugal
- Pharmacological Sciences Department, Faculty of Pharmacy, Universidade de Lisboa, Lisbon, Portugal
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14
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Roeykens HJJ, De Moor RJG. Diurnal variations and pulpal status: is there a need for FFT besides LDF? Lasers Med Sci 2018; 33:1891-1900. [PMID: 29948454 DOI: 10.1007/s10103-018-2550-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 05/21/2018] [Indexed: 11/28/2022]
Abstract
The aim of this article was to investigate the use of laser Doppler flowmetry (LDF) combined with a fast Fourier transformation (FFT). LDF data in relation to three different scenarios were evaluated: (a) LDF records of a right central upper incisor of one patient were used for FFT analysis. These records were obtained by means of 30 pre-manufactured splints, handled by dentists without any experience in LDF recording. (b) Diurnal variations in one patient were analysed with LDF and FFT using 11 splints by one and same experienced investigator at four specific moments of the day. (c) Pulpal status was analysed using 17 splints. Eleven for a patient, standing as case model and six splints for six other patients. In this specific group, each patient had one vital and one non-vital central maxillary incisor and was analysed separately by LDF and FFT. The data of assessment (b) showed diurnal variations on LDF values of almost 80%, indicating that LDF registration is best performed in the same time period of the day. Data verification with FFT confirmed the findings without FFT of assessment (a) and (b). In assessment, (c) FFT demonstrated a clear distinction between a vital and a non-vital pulp for those cases with one vital tooth and one root canal treated tooth. In those cases with one vital incisor and the other traumatised, FFT was undeterminated. Considered that FFT was obtained after LDF recording and remained undeterminated for a decision in cases with decreasing pulpal blood flow in time, the added value of FFT in pulpal traumatology was minimal.
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Affiliation(s)
- Herman J J Roeykens
- Department of Reconstructive Dentistry and Endodontology, Ghent Dental Laser Centre, Ghent Dental Photonics Research Cluster, Dental School, Ghent University Hospital, Ghent University, C.Heymanslaan 10 -1P8, 9000, Ghent, Belgium.
| | - Roeland J G De Moor
- Department of Reconstructive Dentistry and Endodontology, Ghent Dental Laser Centre, Ghent Dental Photonics Research Cluster, Dental School, Ghent University Hospital, Ghent University, C.Heymanslaan 10 -1P8, 9000, Ghent, Belgium
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15
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Clough GF, Kuliga KZ, Chipperfield AJ. Flow motion dynamics of microvascular blood flow and oxygenation: Evidence of adaptive changes in obesity and type 2 diabetes mellitus/insulin resistance. Microcirculation 2018; 24. [PMID: 27809397 DOI: 10.1111/micc.12331] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 10/31/2016] [Indexed: 11/29/2022]
Abstract
An altered spatial heterogeneity and temporal stability of network perfusion can give rise to a limited adaptive ability to meet metabolic demands. Derangement of local flow motion activity is associated with reduced microvascular blood flow and tissue oxygenation, and it has been suggested that changes in flow motion activity may provide an early indicator of declining, endothelial, neurogenic, and myogenic regulatory mechanisms and signal the onset and progression of microvascular pathophysiology. This short conference review article explores some of the evidence for altered flow motion dynamics of blood flux signals acquired using laser Doppler fluximetry in the skin in individuals at risk of developing or with cardiometabolic disease.
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Affiliation(s)
| | - Katarzyna Z Kuliga
- Faculty of Medicine, University of Southampton, Southampton, UK.,Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - Andrew J Chipperfield
- Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
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16
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Greaney JL, Kutz JL, Shank SW, Jandu S, Santhanam L, Alexander LM. Impaired Hydrogen Sulfide-Mediated Vasodilation Contributes to Microvascular Endothelial Dysfunction in Hypertensive Adults. Hypertension 2017; 69:902-909. [PMID: 28348008 DOI: 10.1161/hypertensionaha.116.08964] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 01/03/2017] [Accepted: 02/17/2017] [Indexed: 12/22/2022]
Abstract
Reductions in hydrogen sulfide (H2S) production have been implicated in the pathogenesis of vascular dysfunction in animal models of hypertension; however, no studies have examined a functional role for H2S in contributing to microvascular dysfunction in hypertensive (HTN) adults. We hypothesized that endogenous production of H2S would be reduced, impaired endothelium-dependent vasodilation would be mediated by reductions in H2S-dependent vasodilation, and vascular responsiveness to exogenous H2S (sodium sulfide) would be attenuated in HTN compared to normotensive adults. Fifteen normotensive (51±2 years; blood pressure, 116±3/76±3 mm Hg) and 14 HTN adults (57±2 years; blood pressure 140±3/89±2 mm Hg) participated. H2S biosynthetic enzyme expression (Western blot) and substrate-dependent H2S production (amperometric probe) were measured in cutaneous tissue homogenates. Red cell flux (laser Doppler flowmetry) was measured during graded perfusions of acetylcholine (ACh; 10-6-10-1 mol/L) and sodium sulfide (10-5-101 mol/L) using intradermal microdialysis; the functional role of H2S was determined using pharmacological inhibition with aminooxyacetic acid (0.5 mmol/L). H2S biosynthetic enzyme expression and substrate-dependent H2S production were reduced in HTN adults (all P<0.05). ACh-induced endothelium-dependent vasodilation was blunted in HTN adults (P=0.012). Aminooxyacetic acid attenuated ACh-induced vasodilation in normotensive adults (ACh, 1.31±0.13 versus ACh+aminooxyacetic acid, 1.07±0.09 flux/mm Hg; P=0.025) but had no effect on vasodilation in HTN adults (ACh, 1.16±0.10 versus ACh+aminooxyacetic acid, 1.37±0.11 flux/mm Hg; P=0.47). Sodium sulfide-induced vasodilation was not different between groups. Collectively, these findings indicate that while the microvasculature maintains the ability to vasodilate in response to exogenous H2S, reductions in endogenous synthesis and H2S-dependent vasodilation contribute to endothelial dysfunction in human hypertension.
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Affiliation(s)
- Jody L Greaney
- From the Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park (J.L.G., J.L.K., S.W.S., L.M.A.); Department of Exercise Science, Shenandoah University, Winchester, VA (J.L.K.); and Departments of Anesthesia and Critical Care Medicine and Bioengineering, Johns Hopkins University School of Medicine, Baltimore, MD (S.J., L.S.)
| | - Jessica L Kutz
- From the Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park (J.L.G., J.L.K., S.W.S., L.M.A.); Department of Exercise Science, Shenandoah University, Winchester, VA (J.L.K.); and Departments of Anesthesia and Critical Care Medicine and Bioengineering, Johns Hopkins University School of Medicine, Baltimore, MD (S.J., L.S.)
| | - Sean W Shank
- From the Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park (J.L.G., J.L.K., S.W.S., L.M.A.); Department of Exercise Science, Shenandoah University, Winchester, VA (J.L.K.); and Departments of Anesthesia and Critical Care Medicine and Bioengineering, Johns Hopkins University School of Medicine, Baltimore, MD (S.J., L.S.)
| | - Sandeep Jandu
- From the Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park (J.L.G., J.L.K., S.W.S., L.M.A.); Department of Exercise Science, Shenandoah University, Winchester, VA (J.L.K.); and Departments of Anesthesia and Critical Care Medicine and Bioengineering, Johns Hopkins University School of Medicine, Baltimore, MD (S.J., L.S.)
| | - Lakshmi Santhanam
- From the Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park (J.L.G., J.L.K., S.W.S., L.M.A.); Department of Exercise Science, Shenandoah University, Winchester, VA (J.L.K.); and Departments of Anesthesia and Critical Care Medicine and Bioengineering, Johns Hopkins University School of Medicine, Baltimore, MD (S.J., L.S.)
| | - Lacy M Alexander
- From the Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park (J.L.G., J.L.K., S.W.S., L.M.A.); Department of Exercise Science, Shenandoah University, Winchester, VA (J.L.K.); and Departments of Anesthesia and Critical Care Medicine and Bioengineering, Johns Hopkins University School of Medicine, Baltimore, MD (S.J., L.S.).
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17
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Kuliga KZ, Gush R, Clough GF, Chipperfield AJ. Time-dependent Behavior of Microvascular Blood Flow and Oxygenation: a Predictor of Functional Outcomes. IEEE Trans Biomed Eng 2017; 65:1049-1056. [DOI: 10.1109/tbme.2017.2737328] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Wong BJ, Hollowed CG. Current concepts of active vasodilation in human skin. Temperature (Austin) 2016; 4:41-59. [PMID: 28349094 PMCID: PMC5356216 DOI: 10.1080/23328940.2016.1200203] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/07/2016] [Accepted: 06/07/2016] [Indexed: 10/30/2022] Open
Abstract
In humans, an increase in internal core temperature elicits large increases in skin blood flow and sweating. The increase in skin blood flow serves to transfer heat via convection from the body core to the skin surface while sweating results in evaporative cooling of the skin. Cutaneous vasodilation and sudomotor activity are controlled by a sympathetic cholinergic active vasodilator system that is hypothesized to operate through a co-transmission mechanism. To date, mechanisms of cutaneous active vasodilation remain equivocal despite many years of research by several productive laboratory groups. The purpose of this review is to highlight recent advancements in the field of cutaneous active vasodilation framed in the context of some of the historical findings that laid the groundwork for our current understanding of cutaneous active vasodilation.
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Affiliation(s)
- Brett J. Wong
- Department of Kinesiology & Health, Georgia State University, Atlanta, GA, USA
| | - Casey G. Hollowed
- Department of Kinesiology & Health, Georgia State University, Atlanta, GA, USA
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19
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Hellmann M, Roustit M, Cracowski JL. Skin microvascular endothelial function as a biomarker in cardiovascular diseases? Pharmacol Rep 2015; 67:803-10. [DOI: 10.1016/j.pharep.2015.05.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 05/13/2015] [Accepted: 05/13/2015] [Indexed: 11/17/2022]
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20
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Hodges GJ, Kellogg DL, Johnson JM. Effect of skin temperature on cutaneous vasodilator response to the β-adrenergic agonist isoproterenol. J Appl Physiol (1985) 2015; 118:898-903. [PMID: 25701007 DOI: 10.1152/japplphysiol.01071.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/13/2015] [Indexed: 11/22/2022] Open
Abstract
The vascular response to local skin cooling is dependent in part on a cold-induced translocation of α2C-receptors and an increased α-adrenoreceptor function. To discover whether β-adrenergic function might contribute, we examined whether β-receptor sensitivity to the β-agonist isoproterenol was affected by local skin temperature. In seven healthy volunteers, skin blood flow was measured from the forearm by laser-Doppler flowmetry and blood pressure was measured by finger photoplethysmography. Data were expressed as cutaneous vascular conductance (CVC; laser-Doppler flux/mean arterial blood pressure). Pharmacological agents were administered via intradermal microdialysis. We prepared four skin sites: one site was maintained at a thermoneutral temperature of 34°C (32 ± 10%CVCmax) one site was heated to 39°C (38 ± 11%CVCmax); and two sites were cooled, one to 29°C (22 ± 7%CVCmax) and the other 24°C (16 ± 4%CVCmax). After 20 min at these temperatures to allow stabilization of skin blood flow, isoproterenol was perfused in concentrations of 10, 30, 100, and 300 μM. Each concentration was perfused for 15 min. Relative to the CVC responses to isoproterenol at the thermoneutral skin temperature (34°C) (+21 ± 10%max), low skin temperatures reduced (at 29°C) (+17 ± 6%max) or abolished (at 24°C) (+1 ± 5%max) the vasodilator response, and warm (39°C) skin temperatures enhanced the vasodilator response (+40 ± 9%max) to isoproterenol. These data indicate that β-adrenergic function was influenced by local skin temperature. This finding raises the possibility that a part of the vasoconstrictor response to direct skin cooling could include reduced background β-receptor mediated vasodilation.
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Affiliation(s)
- Gary J Hodges
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada; Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and
| | - Dean L Kellogg
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - John M Johnson
- Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas; and
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