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Laser speckle contrast imaging and laser Doppler flowmetry reproducibly assess reflex cutaneous vasoconstriction. Microvasc Res 2022; 142:104363. [DOI: 10.1016/j.mvr.2022.104363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 11/20/2022]
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Keramidas ME, Kölegård R, Sundblad P, Sköldefors H, Eiken O. Differential responsiveness of glabrous and nonglabrous skin to local transmural pressure elevations: impact of 5 weeks of iterative local pressure loading. Am J Physiol Regul Integr Comp Physiol 2021; 321:R742-R750. [PMID: 34523378 DOI: 10.1152/ajpregu.00151.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the in vivo pressure-flow relationship in human cutaneous vessels during acute and repeated elevations of local transmural pressure. In 10 healthy men, red blood cell flux was monitored simultaneously on the nonglabrous skin of the forearm and the glabrous skin of a finger during a vascular pressure provocation, wherein the blood vessels of an arm were exposed to a wide range of stepwise increasing distending pressures. Forearm skin blood flux was relatively stable at slight and moderate elevations of distending pressure, whereas it increased approximately three- to fourfold at the highest levels (P = 0.004). Finger blood flux, on the contrary, dropped promptly and consistently throughout the provocation (P < 0.001). Eight of the subjects repeated the provocation trial after a 5-wk pressure-training regimen, during which the vasculature in one arm was exposed intermittently (40 min, 3 times/wk) to increased transmural pressure (from +65 mmHg week 1 to +105 mmHg week 5). The training regimen diminished the pressure-induced increase in forearm blood flux by ∼34% (P = 0.02), whereas it inhibited the reduction in finger blood flux (P < 0.001) in response to slight and moderate distending pressure elevations. The present findings demonstrate that during local pressure perturbations, the cutaneous autoregulatory function is accentuated in glabrous compared with in the nonglabrous skin regions. Prolonged intermittent regional exposures to augmented intravascular pressure blunt the responsiveness of the glabrous skin but enhance arteriolar pressure resistance in the nonglabrous skin.
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Affiliation(s)
- Michail E Keramidas
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Roger Kölegård
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Patrik Sundblad
- Department of Laboratory Medicine, Division of Clinical Physiology, Karolinska Institute, Stockholm, Sweden.,Department of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Håkan Sköldefors
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Ola Eiken
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
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Cappel MA, Cappel JA, Wetter DA. Pernio (Chilblains), SARS-CoV-2, and COVID Toes Unified Through Cutaneous and Systemic Mechanisms. Mayo Clin Proc 2021; 96:989-1005. [PMID: 33714595 PMCID: PMC7826004 DOI: 10.1016/j.mayocp.2021.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 01/05/2021] [Accepted: 01/13/2021] [Indexed: 12/14/2022]
Abstract
Pernio or chilblains is characterized by erythema and swelling at acral sites (eg, toes and fingers), typically triggered by cold exposure. Clinical and histopathologic features of pernio are well described, but the pathogenesis is not entirely understood; vasospasm and a type I interferon (IFN-I) immune response are likely involved. During the coronavirus disease 2019 (COVID-19) pandemic, dermatologists have observed an increase in pernio-like acral eruptions. Direct causality of pernio due to COVID-19 has not been established in many cases because of inconsistent testing methods (often negative results) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, a form of COVID-19‒associated pernio (also called COVID toes) is probable because of increased occurrence, frequently in young patients with no cold exposure or a history of pernio, and reports of skin biopsies with positive SARS-CoV-2 immunohistochemistry. PubMed was searched between January 1, 2020, and December 31, 2020 for publications using the following keywords: pernio, chilblain, and acral COVID-19. On the basis of our review of the published literature, we speculate that several unifying cutaneous and systemic mechanisms may explain COVID-19‒associated pernio: (1) SARS-CoV-2 cell infection occurs through the cellular receptor angiotensin-converting enzyme 2 mediated by transmembrane protease serine 2, subsequently affecting the renin-angiotensin-aldosterone system with an increase in the vasoconstricting, pro-inflammatory, and prothrombotic angiotensin II pathway. (2) Severe acute respiratory syndrome coronavirus 2 cell infection triggers an immune response with robust IFN-I release in patients predisposed to COVID-19‒associated pernio. (3) Age and sex discrepancies correlated with COVID-19 severity and manifestations, including pernio as a sign of mild disease, are likely explained by age-related immune and vascular differences influenced by sex hormones and genetics, which affect susceptibility to viral cellular infection, the renin-angiotensin-aldosterone system balance, and the IFN-I response.
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Key Words
- ace2, angiotensin-converting enzyme 2
- adam17, a disintegrin and metalloproteinase 17
- ang, angiotensin
- ang1-7, angiotensin-(1-7)
- angii, angiotensin ii
- at1r, angiotensin type 1 receptor
- at2r, angiotensin type 2 receptor
- covid-19, coronavirus disease 2019
- hif-1α, hypoxia-inducible factor 1α
- ifn, interferon
- ifn-i, type i interferon
- ifn-α, interferon α
- il, interleukin
- mxa, myxovirus resistance protein a
- no, nitric oxide
- nsp, nonstructural protein
- pcr, polymerase chain reaction
- pdc, plasmacytoid dendritic cell
- raas, renin-angiotensin-aldosterone system
- s1, spike protein 1
- s2, spike protein 2
- sars-cov, severe acute respiratory syndrome coronavirus
- sars-cov-2, severe acute respiratory syndrome coronavirus 2
- th17, helper t cell 17
- tlr7, toll-like receptor 7
- tmprss2, transmembrane protease serine 2
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Affiliation(s)
- Mark A Cappel
- Gulf Coast Dermatopathology Laboratory, Dermatology Associates of Tampa Bay, Tampa, FL
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Kim J, Franke WD, Lang JA. Improved endothelial-dependent and endothelial-independent skin vasodilator responses following remote ischemic preconditioning. Am J Physiol Heart Circ Physiol 2020; 318:H110-H115. [PMID: 31774694 DOI: 10.1152/ajpheart.00467.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
One week of daily remote ischemic preconditioning (RIPC) improves cutaneous vasodilatory (VD) function. However, the underlying mechanisms and the number of sessions needed to optimize this adaptive response remain unclear. We hypothesized that the responses to localized heating of the skin will be greater after 2 wk as opposed to 1 wk of RIPC. Furthermore, 2 wk of repeated RIPC will augment cutaneous VD responses to thermal and pharmacological stimuli. In methods, twenty-four participants (24 ± 2 yr; 13 men, 11 women) performed repeated RIPC (7 daily sessions over 1 wk, n = 11; 12 sessions over 2 wk, n = 13), consisting of four repetitions of 5 min of arm blood flow occlusion separated by 5 min reperfusion. Laser speckle contrast imaging was used to measure skin blood flow responses, in perfusion units (PU), to local heating (Tloc = 42°C), acetylcholine (ACh), and sodium nitroprusside (SNP) before and after repeated RIPC. Data were expressed as cutaneous vascular conductance (CVC, in PU/mmHg). In results, the VD response to local heating increased after RIPC (∆CVC from baseline; 1 wk: 0.94 ± 0.11 to 1.19 ± 0.15, 2 wk: 1.18 ± 0.07 to 1.33 ± 0.10 PU/mmHg; P < 0.05) but the ∆CVC did not differ between weeks. SNP-induced VD increased after 2 wk of RIPC (∆CVC; 0.34 ± 0.07 to 0.63 ± 0.11 PU/mmHg; P < 0.05), but ACh-induced VD did not. In conclusion, repeated RIPC improves local heating- and SNP-mediated cutaneous VD. When compared with 1 wk of RIPC, 2 wk of RIPC does not induce further improvements in cutaneous VD function.NEW & NOTEWORTHY Repeated RIPC increases the cutaneous vasodilatory response to local heating and to sodium nitroprusside but not to acetylcholine. Thus, endothelial-independent and local heating-mediated cutaneous vasodilation are improved following RIPC. However, 2 wk of RIPC sessions are not more effective than 1 wk of RIPC sessions in enhancing local heating-mediated cutaneous vasodilation.
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Affiliation(s)
- Jahyun Kim
- Department of Kinesiology, Iowa State University, Ames, Iowa
| | - Warren D Franke
- Department of Kinesiology, Iowa State University, Ames, Iowa
| | - James A Lang
- Department of Kinesiology, Iowa State University, Ames, Iowa.,Department of Physical Therapy, Des Moines University, Des Moines, Iowa
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Fujii N, Hatam K, McGarr GW, Meade RD, Boulay P, Nishiyasu T, Kenny GP. Exogenous Activation of Protease-Activated Receptor 2 Attenuates Cutaneous Vasodilatation and Sweating in Older Men Exercising in the Heat. Skin Pharmacol Physiol 2019; 32:235-243. [PMID: 31220834 DOI: 10.1159/000500643] [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: 03/03/2019] [Accepted: 04/26/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Protease-activated receptor 2 (PAR2) exists in the cutaneous vasculature and eccrine sweat glands. We previously showed that in young habitually active men, exogenous PAR2 activation via the agonist SLIGKV-NH2 had no effect on heat loss responses of cutaneous vasodilatation and sweating during rest or exercise in the heat. However, ageing is associated with altered mechanisms governing these responses. Thus, the effect of exogenous PAR2 activation on cutaneous vasodilatation and sweating in older individuals may differ from that in young adults. METHODS Local cutaneous vascular conductance (CVC) and sweat rate were measured in 9 older males (62 ± 4 years) at four forearm skin sites treated with the following: (1) lactated Ringer solution (control), (2) 0.05 mM, (3) 0.5 mM, or (4) 5 mM SLIGKV-NH2. Measurements were performed while participants rested in a non-heat-stress environment (25°C) for ∼60 min and an additional 50 min thereafter in the heat (40°C). Participants then performed 50 min of cycling at a fixed metabolic heat load of 200 W/m2 (to maintain the same thermal drive for heat loss between participants) followed by a 30-min recovery. RESULTS CVC during non-heat-stress resting was elevated from the control site with 5 mM SLIGKV-NH2 (p ≤ 0.05), but this response was not observed during ambient heat exposure. By contrast, 5 mM SLIGKV-NH2 lowered CVC during the early stage (10 and 20 min) of exercise compared to the control site (all p ≤ 0.05). Although sweating during non-heat-stressed and heat-stressed resting was not affected by any dose of SLIGKV-NH2, it was reduced with all SLIGKV-NH2 doses relative to the control site during and following exercise (all p ≤ 0.05). CONCLUSION We show that while exogenous PAR2 activation induces cutaneous vasodilatation at rest under non-heat-stressed conditions, it attenuates cutaneous vasodilatation and sweating during and following an exercise-induced heat stress in older men.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada, .,Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan,
| | - Kion Hatam
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
| | - Gregory W McGarr
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Québec, Canada
| | - Takeshi Nishiyasu
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
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Alba BK, Castellani JW, Charkoudian N. Cold‐induced cutaneous vasoconstriction in humans: Function, dysfunction and the distinctly counterproductive. Exp Physiol 2019; 104:1202-1214. [DOI: 10.1113/ep087718] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 04/30/2019] [Indexed: 01/03/2023]
Affiliation(s)
- Billie K. Alba
- Thermal & Mountain Medicine Division US Army Research Institute of Environmental Medicine Natick MA USA
- Oak Ridge Institute of Science and Education Belcamp MD USA
| | - John W. Castellani
- Thermal & Mountain Medicine Division US Army Research Institute of Environmental Medicine Natick MA USA
| | - Nisha Charkoudian
- Thermal & Mountain Medicine Division US Army Research Institute of Environmental Medicine Natick MA USA
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Lang JA, Kim J, Franke WD, Vianna LC. Seven consecutive days of remote ischaemic preconditioning improves cutaneous vasodilatory capacity in young adults. J Physiol 2018; 597:757-765. [PMID: 30506681 DOI: 10.1113/jp277185] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/30/2018] [Indexed: 01/15/2023] Open
Abstract
KEY POINTS Remote ischaemic preconditioning (RIPC), induced by brief bouts of ischaemia followed by reperfusion, confers vascular adaptations that protect against subsequent bouts of ischaemia; however, the effect of RIPC repeated over several days on the human microcirculation is unknown. Using skin as a model, microvascular function was assessed at a control and a NO-inhibited area of skin before 1 day after and 1 week after administering seven consecutive days of repeated RIPC on the contralateral arm. Maximal vasodilatation was increased by ∼20-50% following 7 days of repeated RIPC, and this response remained elevated 1 week after stopping RIPC; however, NO-mediated vasodilatation was not affected by the RIPC stimulus. These data indicate that repeated RIPC augments maximal vasodilatation, but the underlying mechanism for this improvement is largely independent of NO. This finding suggests a role for other endothelium-derived mediators and/or for endothelium-independent adaptations with repeated RIPC. ABSTRACT Remote ischaemic preconditioning (RIPC), induced by intermittent periods of ischaemia followed by reperfusion, confers cardiovascular protection from subsequent ischaemic bouts. RIPC increases conduit and resistance vessel function; however, the effect of RIPC on the microvasculature remains unclear. Using human skin as a microvascular model, we hypothesized that cutaneous vasodilatory (VD) function elicited by localized heating would be increased following repeated RIPC. Ten participants (23 ± 1 years, 6 males, 4 females) performed RIPC for seven consecutive days. Each daily RIPC session consisted of 4 repetitions of 5 min of arm blood flow occlusion interspersed by 5 min reperfusion. Before, 1 day after and 1 week after the 7 days of RIPC, two microdialysis fibres were placed in ventral forearm skin for continuous infusion of Ringer solution or 20 mM l-NAME. Red blood cell flux was measured by laser Doppler flowmetry at each fibre site during local heating (Tloc = 39°C) and during maximal VD elicited by heating (Tloc = 43°C) and 28 mM sodium nitroprusside infusion. Data were normalized to cutaneous vascular conductance (flux/mmHg). Seven days of RIPC did not alter the nitric oxide (NO) contribution to the VD response to local heating (P > 0.05). However, the maximal VD was augmented (Pre: 2.5 ± 0.2, Post: 3.8 ± 0.5 flux/mmHg; P < 0.05) and remained elevated 1 week post RIPC (3.3 ± 0.4 flux/mmHg; P < 0.05). Repeated RIPC improves maximal VD but does not affect NO-mediated VD in the cutaneous microvasculature. This finding suggests that other factors may explain the vasodilatory adaptations that occur following repeated RIPC.
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Affiliation(s)
- James A Lang
- Department of Kinesiology, Iowa State University, Ames, IA, USA.,Department of Physical Therapy, Des Moines University, Des Moines, IA, USA
| | - Jahyun Kim
- Department of Kinesiology, Iowa State University, Ames, IA, USA
| | - Warren D Franke
- Department of Kinesiology, Iowa State University, Ames, IA, USA
| | - Lauro C Vianna
- Faculty of Physical Education, University of Brasilia, Federal District, Brazil
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Lang JA, Krajek AC. Age-related differences in the cutaneous vascular response to exogenous angiotensin II. Am J Physiol Heart Circ Physiol 2018; 316:H516-H521. [PMID: 30499715 DOI: 10.1152/ajpheart.00509.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Angiotensin II (ANG II) is locally produced in human skin and contributes to the reflex vasoconstriction (VC) response in aged but not young skin. We hypothesized that the exogenous ANG II-mediated VC response would be greater in older adults and would be affected by inhibition of adrenoreceptor or ANG II type II receptor (AT2R) pathways. Three microdialysis (MD) fibers were placed in the forearm skin of 11 young (26 ± 3 yr) and 11 older (68 ± 4 yr) individuals for perfusion of 1) Ringer solution (control), 2) adrenoreceptor blockade with yohimbine + propranolol, and 3) AT2R inhibition with PD-123319. ANG II was then added to the perfusates at eight graded dose concentrations ranging from 10-10 to 10-3 M. Laser Doppler flux was measured at each MD site, and cutaneous vascular conductance (CVC) was calculated as CVC = laser Doppler flux/mean arterial pressure and normalized to baseline CVC values collected before ANG II perfusion (%ΔCVCbaseline). At the control site, older adults (-34 ± 4%ΔCVCbaseline) exhibited a greater peak VC compared with young adults (-22 ± 2%ΔCVCbaseline, P < 0.05), which was attenuated with adrenoreceptor blockade. Young skin exhibited a vasodilation in response to lower ANG II doses that was inhibited with AT2R inhibition. AT2R inhibition also increased the VC response to higher ANG II doses such that young skin responded similarly to older skin. These results indicate that ANG II has a greater VC influence in older than young individuals. Furthermore, ANG II may be affecting multiple targets, including adrenergic and AT2R pathways. NEW & NOTEWORTHY Intradermal perfusion of successive doses of angiotensin II (ANG II) revealed a role for ANG II type II receptors and dose-dependent, ANG II-mediated vasodilation in young but not older adults. In contrast, older adults exhibited greater vasoconstriction for a given dose of ANG II. The increased vasoconstriction in older adults was subsequently blunted with adrenoreceptor blockade, which indicates an interaction between ANG II and adrenergic signaling pathways in the cutaneous microcirculation.
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Affiliation(s)
- James A Lang
- Department of Kinesiology, Iowa State University , Ames, Iowa.,Department of Physical Therapy, Des Moines University , Des Moines, Iowa
| | - Alex C Krajek
- Department of Physical Therapy, Des Moines University , Des Moines, Iowa
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McNeely BD, Meade RD, Fujii N, Seely AJE, Sigal RJ, Kenny GP. Fluid replacement modulates oxidative stress- but not nitric oxide-mediated cutaneous vasodilation and sweating during prolonged exercise in the heat. Am J Physiol Regul Integr Comp Physiol 2017; 313:R730-R739. [PMID: 28931548 PMCID: PMC5814697 DOI: 10.1152/ajpregu.00284.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/11/2017] [Accepted: 09/11/2017] [Indexed: 01/29/2023]
Abstract
The roles of nitric oxide synthase (NOS), reactive oxygen species (ROS), and angiotensin II type 1 receptor (AT1R) activation in regulating cutaneous vasodilation and sweating during prolonged (≥60 min) exercise are currently unclear. Moreover, it remains to be determined whether fluid replacement (FR) modulates the above thermoeffector responses. To investigate, 11 young men completed 90 min of continuous moderate intensity (46% V̇o2peak) cycling performed at a fixed rate of metabolic heat production of 600 W (No FR condition). On a separate day, participants completed a second session of the same protocol while receiving FR to offset sweat losses (FR condition). Cutaneous vascular conductance (CVC) and local sweat rate (LSR) were measured at four intradermal microdialysis forearm sites perfused with: 1) lactated Ringer (Control); 2) 10 mM NG-nitro-l-arginine methyl ester (l-NAME, NOS inhibition); 3) 10 mM ascorbate (nonselective antioxidant); or 4) 4.34 nM losartan (AT1R inhibition). Relative to Control (71% CVCmax at both time points), CVC with ascorbate (80% and 83% CVCmax) was elevated at 60 and 90 min of exercise during FR (both P < 0.02) but not at any time during No FR (all P > 0.31). In both conditions, CVC was reduced at end exercise with l-NAME (60% CVCmax; both P < 0.02) but was not different relative to Control at the losartan site (76% CVCmax; both P > 0.19). LSR did not differ between sites in either condition (all P > 0.10). We conclude that NOS regulates cutaneous vasodilation, but not sweating, irrespective of FR, and that ROS influence cutaneous vasodilation during prolonged exercise with FR.
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Affiliation(s)
- Brendan D McNeely
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
| | - Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
- Faculty of Health and Sports Science, University of Tsukuba, Tsukuba, Japan
| | - Andrew J E Seely
- Thoracic Surgery and Critical Care Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada
| | - Ronald J Sigal
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; and
- Departments of Medicine, Cardiac Sciences and Community Health Sciences, Faculties of Medicine and Kinesiology University of Calgary, Calgary, Alberta, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada;
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; and
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Lang JA, Krajek AC, Smaller KA. Evidence for a functional vasoconstrictor role for ATP in the human cutaneous microvasculature. Exp Physiol 2017; 102:684-693. [PMID: 28295755 DOI: 10.1113/ep086231] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/06/2017] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? In young adults, about half of the cold-related reduction in skin blood flow during cold exposure is mediated by noradrenaline, while the remainder is attributable to other substances co-released with noradrenaline that have yet to be identified. What is the main finding and its importance? Purinergic receptor blockade blunted the vasoconstriction response to whole-body cooling and to intradermal administration of tyramine. These results indicate that ATP is necessary to vasoconstrict blood vessels in the skin adequately and prevent heat loss in a cold environment. Noradrenaline is responsible for eliciting ∼60% of the reflex cutaneous vasoconstriction (VC) response in young adults, while the remainder is attributable to one or more unidentified co-released sympathetic adrenergic neurotransmitter(s). Inconsistent evidence has placed neuropeptide Y in this role; however, other putative cotransmitters have yet to be tested. We hypothesize that ATP contributes to the reflex cutaneous VC response. Two protocols were conducted in young adults (n = 10); both involved the placement of three microdialysis probes in forearm skin and whole-body cooling (skin temperature = 30.5°C). In protocol 1, the following solutions were infused: (i) lactated Ringer solution (control); (ii) 10 mm l-NAME; and (iii) purinergic receptor blockade with 1 mm suramin plus l-NAME. In protocol 2, the following solutions were infused: (i) lactated Ringer solution; (ii) suramin plus l-NAME; and (iii) suramin plus l-NAME plus adrenoreceptor blockade with 5 mm yohimbine plus 1 mm propranolol. Laser Doppler flux (LDF) was measured over each microdialysis site, and cutaneous vascular conductance (CVC) was calculated (CVC = LDF/MAP) and expressed as percentage changes from baseline (%ΔCVCBASELINE ). l-NAME was used to block the vasodilatory influence of ATP and unmask the P2 X-mediated VC response to exogenous ATP infusion (-21 ± 6%ΔCVCBASELINE ). During cooling, the VC response (control, -39 ± 8%ΔCVCBASELINE ) was attenuated at the suramin site (-21 ± 4%ΔCVCBASELINE ) and further blunted with combined adrenoreceptor blockade (-9 ± 3%ΔCVCBASELINE ; P < 0.05). Compared with the control site (-22 ± 5%ΔCVCBASELINE ), suramin inhibited pharmacologically induced VC to tyramine (-12 ± 6%ΔCVCBASELINE ; P < 0.05), which displaces adrenergic neurotransmitters from axon terminals. These data indicate that ATP contributes to the cutaneous VC response in humans.
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Affiliation(s)
- James A Lang
- Department of Physical Therapy, Des Moines University, Des Moines, IA, USA
| | - Alex C Krajek
- Department of Physical Therapy, Des Moines University, Des Moines, IA, USA
| | - Kevin A Smaller
- Department of Neuroscience, Drake University, Des Moines, IA, USA
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Fujii N, Amano T, Halili L, Louie JC, Zhang SY, McNeely BD, Kenny GP. Intradermal administration of endothelin-1 attenuates endothelium-dependent and -independent cutaneous vasodilation via Rho kinase in young adults. Am J Physiol Regul Integr Comp Physiol 2016; 312:R23-R30. [PMID: 27881399 DOI: 10.1152/ajpregu.00368.2016] [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] [Received: 08/29/2016] [Revised: 10/31/2016] [Accepted: 11/18/2016] [Indexed: 01/02/2023]
Abstract
We recently showed that intradermal administration of endothelin-1 diminished endothelium-dependent and -independent cutaneous vasodilation. We evaluated the hypothesis that Rho kinase may be a mediator of this response. We also sought to evaluate if endothelin-1 increases sweating. In 12 adults (25 ± 6 yr), we measured cutaneous vascular conductance (CVC) and sweating during 1) endothelium-dependent vasodilation induced via administration of incremental doses of methacholine (0.25, 5, 100, and 2,000 mM each for 25 min) and 2) endothelium-independent vasodilation induced via administration of 50 mM sodium nitroprusside (20-25 min). Responses were evaluated at four skin sites treated with either 1) lactated Ringer solution (Control), 2) 400 nM endothelin-1, 3) 3 mM HA-1077 (Rho kinase inhibitor), or 4) endothelin-1+HA-1077. Pharmacological agents were intradermally administered via microdialysis. Relative to the Control site, endothelin-1 attenuated endothelium-dependent vasodilation (CVC at 2,000 mM methacholine, 80 ± 10 vs. 56 ± 15%max, P < 0.01); however, this response was not detected when the Rho kinase inhibitor was simultaneously administered (CVC at 2,000 mM methacholine for Rho kinase inhibitor vs. endothelin-1 + Rho kinase inhibitor sites: 73 ± 9 vs. 72 ± 11%max, P > 0.05). Endothelium-independent vasodilation was attenuated by endothelin-1 compared with the Control site (CVC, 92 ± 13 vs. 70 ± 14%max, P < 0.01). However, in the presence of Rho kinase inhibition, endothelin-1 did not affect endothelium-independent vasodilation (CVC at Rho kinase inhibitor vs. endothelin-1+Rho kinase inhibitor sites: 81 ± 9 vs. 86 ± 10%max, P > 0.05). There was no between-site difference in sweating throughout (P > 0.05). We show that in young adults, Rho kinase is an important mediator of the endothelin-1-mediated attenuation of endothelium-dependent and -independent cutaneous vasodilation, and that endothelin-1 does not increase sweating.
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Affiliation(s)
- Naoto Fujii
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Tatsuro Amano
- Laboratory for Exercise and Environmental Physiology, Faculty of Education, Niigata University, Niigata, Japan
| | - Lyra Halili
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Jeffrey C Louie
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Sarah Y Zhang
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Brendan D McNeely
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Canada; and
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Greaney JL, Alexander LM, Kenney WL. Sympathetic control of reflex cutaneous vasoconstriction in human aging. J Appl Physiol (1985) 2015; 119:771-82. [PMID: 26272321 DOI: 10.1152/japplphysiol.00527.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
This Synthesis highlights a series of recent studies that has systematically interrogated age-related deficits in cold-induced skin vasoconstriction. In response to cold stress, a reflex increase in sympathetic nervous system activity mediates reductions in skin blood flow. Reflex vasoconstriction during cold exposure is markedly impaired in aged skin, contributing to the relative inability of healthy older adults to maintain core temperature during mild cold stress in the absence of appropriate behavioral thermoregulation. This compromised reflex cutaneous vasoconstriction in healthy aging can occur as a result of functional deficits at multiple points along the efferent sympathetic reflex axis, including blunted sympathetic outflow directed to the skin vasculature, reduced presynaptic neurotransmitter synthesis and/or release, and altered end-organ responsiveness at several loci, in addition to potential alterations in afferent thermoreceptor function. Arguments have been made that the relative inability of aged skin to appropriately constrict is due to the aging cutaneous arterioles themselves, whereas other data point to the neural circuitry controlling those vessels. The argument presented herein provides strong evidence for impaired efferent sympathetic control of the peripheral cutaneous vasculature during whole body cold exposure as the primary mechanism responsible for attenuated vasoconstriction.
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Affiliation(s)
- Jody L Greaney
- Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park, Pennsylvania
| | - Lacy M Alexander
- Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park, Pennsylvania
| | - W Larry Kenney
- Department of Kinesiology, Noll Laboratory, The Pennsylvania State University, University Park, Pennsylvania
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McGinn R, Meade RD, Kenny GP. Angiotensin II in human skin: an age-dependent role for core temperature regulation? Am J Physiol Heart Circ Physiol 2015; 308:H1192-3. [PMID: 25820393 DOI: 10.1152/ajpheart.00227.2015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Ryan McGinn
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Robert D Meade
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
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