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Wee J, Tan XR, Gunther SH, Ihsan M, Leow MKS, Tan DSY, Eriksson JG, Lee JKW. Effects of Medications on Heat Loss Capacity in Chronic Disease Patients: Health Implications Amidst Global Warming. Pharmacol Rev 2023; 75:1140-1166. [PMID: 37328294 DOI: 10.1124/pharmrev.122.000782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 04/20/2023] [Accepted: 05/31/2023] [Indexed: 06/18/2023] Open
Abstract
Pharmacological agents used to treat or manage diseases can modify the level of heat strain experienced by chronically ill and elderly patients via different mechanistic pathways. Human thermoregulation is a crucial homeostatic process that maintains body temperature within a narrow range during heat stress through dry (i.e., increasing skin blood flow) and evaporative (i.e., sweating) heat loss, as well as active inhibition of thermogenesis, which is crucial to avoid overheating. Medications can independently and synergistically interact with aging and chronic disease to alter homeostatic responses to rising body temperature during heat stress. This review focuses on the physiologic changes, with specific emphasis on thermolytic processes, associated with medication use during heat stress. The review begins by providing readers with a background of the global chronic disease burden. Human thermoregulation and aging effects are then summarized to give an understanding of the unique physiologic changes faced by older adults. The effects of common chronic diseases on temperature regulation are outlined in the main sections. Physiologic impacts of common medications used to treat these diseases are reviewed in detail, with emphasis on the mechanisms by which these medications alter thermolysis during heat stress. The review concludes by providing perspectives on the need to understand the effects of medication use in hot environments, as well as a summary table of all clinical considerations and research needs of the medications included in this review. SIGNIFICANCE STATEMENT: Long-term medications modulate thermoregulatory function, resulting in excess physiological strain and predisposing patients to adverse health outcomes during prolonged exposures to extreme heat during rest and physical work (e.g., exercise). Understanding the medication-specific mechanisms of altered thermoregulation has importance in both clinical and research settings, paving the way for work toward refining current medication prescription recommendations and formulating mitigation strategies for adverse drug effects in the heat in chronically ill patients.
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Affiliation(s)
- Jericho Wee
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine (J.W., X.R.T., S.H.G., M.I., M.K.S.L., J.G.E., J.K.W.L.), Department of Pharmacy, Faculty of Science, (D.S.-Y.T), Department of Physiology, Yong Loo Lin School of Medicine (J.K.W.L.), Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine (J.K.W.L.), National University of Singapore, Singapore; Health and Social Sciences, Singapore Institute of Technology, Singapore (X.R.T.); Campus for Research Excellence and Technological Enterprise, Singapore (S.H.G., J.K.W.L.); Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore (M.K.S.L.); Duke-National University of Singapore Medical School, Singapore (M.K.S.L.); Department of Endocrinology, Division of Medicine, Tan Tock Seng Hospital, Singapore (M.K.S.L.); Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore (M.K.S.L., J.G.E.); Folkhalsan Research Center, Helsinki, Finland (J.G.E.); Department of General Practice and Primary Health Care, University of Helsinki, and Helsinki University Hospital, University of Helsinki, Helsinki, Finland (J.G.E.); and Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (J.G.E.)
| | - Xiang Ren Tan
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine (J.W., X.R.T., S.H.G., M.I., M.K.S.L., J.G.E., J.K.W.L.), Department of Pharmacy, Faculty of Science, (D.S.-Y.T), Department of Physiology, Yong Loo Lin School of Medicine (J.K.W.L.), Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine (J.K.W.L.), National University of Singapore, Singapore; Health and Social Sciences, Singapore Institute of Technology, Singapore (X.R.T.); Campus for Research Excellence and Technological Enterprise, Singapore (S.H.G., J.K.W.L.); Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore (M.K.S.L.); Duke-National University of Singapore Medical School, Singapore (M.K.S.L.); Department of Endocrinology, Division of Medicine, Tan Tock Seng Hospital, Singapore (M.K.S.L.); Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore (M.K.S.L., J.G.E.); Folkhalsan Research Center, Helsinki, Finland (J.G.E.); Department of General Practice and Primary Health Care, University of Helsinki, and Helsinki University Hospital, University of Helsinki, Helsinki, Finland (J.G.E.); and Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (J.G.E.)
| | - Samuel H Gunther
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine (J.W., X.R.T., S.H.G., M.I., M.K.S.L., J.G.E., J.K.W.L.), Department of Pharmacy, Faculty of Science, (D.S.-Y.T), Department of Physiology, Yong Loo Lin School of Medicine (J.K.W.L.), Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine (J.K.W.L.), National University of Singapore, Singapore; Health and Social Sciences, Singapore Institute of Technology, Singapore (X.R.T.); Campus for Research Excellence and Technological Enterprise, Singapore (S.H.G., J.K.W.L.); Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore (M.K.S.L.); Duke-National University of Singapore Medical School, Singapore (M.K.S.L.); Department of Endocrinology, Division of Medicine, Tan Tock Seng Hospital, Singapore (M.K.S.L.); Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore (M.K.S.L., J.G.E.); Folkhalsan Research Center, Helsinki, Finland (J.G.E.); Department of General Practice and Primary Health Care, University of Helsinki, and Helsinki University Hospital, University of Helsinki, Helsinki, Finland (J.G.E.); and Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (J.G.E.)
| | - Mohammed Ihsan
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine (J.W., X.R.T., S.H.G., M.I., M.K.S.L., J.G.E., J.K.W.L.), Department of Pharmacy, Faculty of Science, (D.S.-Y.T), Department of Physiology, Yong Loo Lin School of Medicine (J.K.W.L.), Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine (J.K.W.L.), National University of Singapore, Singapore; Health and Social Sciences, Singapore Institute of Technology, Singapore (X.R.T.); Campus for Research Excellence and Technological Enterprise, Singapore (S.H.G., J.K.W.L.); Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore (M.K.S.L.); Duke-National University of Singapore Medical School, Singapore (M.K.S.L.); Department of Endocrinology, Division of Medicine, Tan Tock Seng Hospital, Singapore (M.K.S.L.); Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore (M.K.S.L., J.G.E.); Folkhalsan Research Center, Helsinki, Finland (J.G.E.); Department of General Practice and Primary Health Care, University of Helsinki, and Helsinki University Hospital, University of Helsinki, Helsinki, Finland (J.G.E.); and Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (J.G.E.)
| | - Melvin Khee Shing Leow
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine (J.W., X.R.T., S.H.G., M.I., M.K.S.L., J.G.E., J.K.W.L.), Department of Pharmacy, Faculty of Science, (D.S.-Y.T), Department of Physiology, Yong Loo Lin School of Medicine (J.K.W.L.), Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine (J.K.W.L.), National University of Singapore, Singapore; Health and Social Sciences, Singapore Institute of Technology, Singapore (X.R.T.); Campus for Research Excellence and Technological Enterprise, Singapore (S.H.G., J.K.W.L.); Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore (M.K.S.L.); Duke-National University of Singapore Medical School, Singapore (M.K.S.L.); Department of Endocrinology, Division of Medicine, Tan Tock Seng Hospital, Singapore (M.K.S.L.); Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore (M.K.S.L., J.G.E.); Folkhalsan Research Center, Helsinki, Finland (J.G.E.); Department of General Practice and Primary Health Care, University of Helsinki, and Helsinki University Hospital, University of Helsinki, Helsinki, Finland (J.G.E.); and Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (J.G.E.)
| | - Doreen Su-Yin Tan
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine (J.W., X.R.T., S.H.G., M.I., M.K.S.L., J.G.E., J.K.W.L.), Department of Pharmacy, Faculty of Science, (D.S.-Y.T), Department of Physiology, Yong Loo Lin School of Medicine (J.K.W.L.), Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine (J.K.W.L.), National University of Singapore, Singapore; Health and Social Sciences, Singapore Institute of Technology, Singapore (X.R.T.); Campus for Research Excellence and Technological Enterprise, Singapore (S.H.G., J.K.W.L.); Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore (M.K.S.L.); Duke-National University of Singapore Medical School, Singapore (M.K.S.L.); Department of Endocrinology, Division of Medicine, Tan Tock Seng Hospital, Singapore (M.K.S.L.); Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore (M.K.S.L., J.G.E.); Folkhalsan Research Center, Helsinki, Finland (J.G.E.); Department of General Practice and Primary Health Care, University of Helsinki, and Helsinki University Hospital, University of Helsinki, Helsinki, Finland (J.G.E.); and Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (J.G.E.)
| | - Johan G Eriksson
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine (J.W., X.R.T., S.H.G., M.I., M.K.S.L., J.G.E., J.K.W.L.), Department of Pharmacy, Faculty of Science, (D.S.-Y.T), Department of Physiology, Yong Loo Lin School of Medicine (J.K.W.L.), Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine (J.K.W.L.), National University of Singapore, Singapore; Health and Social Sciences, Singapore Institute of Technology, Singapore (X.R.T.); Campus for Research Excellence and Technological Enterprise, Singapore (S.H.G., J.K.W.L.); Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore (M.K.S.L.); Duke-National University of Singapore Medical School, Singapore (M.K.S.L.); Department of Endocrinology, Division of Medicine, Tan Tock Seng Hospital, Singapore (M.K.S.L.); Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore (M.K.S.L., J.G.E.); Folkhalsan Research Center, Helsinki, Finland (J.G.E.); Department of General Practice and Primary Health Care, University of Helsinki, and Helsinki University Hospital, University of Helsinki, Helsinki, Finland (J.G.E.); and Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (J.G.E.)
| | - Jason Kai Wei Lee
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine (J.W., X.R.T., S.H.G., M.I., M.K.S.L., J.G.E., J.K.W.L.), Department of Pharmacy, Faculty of Science, (D.S.-Y.T), Department of Physiology, Yong Loo Lin School of Medicine (J.K.W.L.), Heat Resilience and Performance Centre, Yong Loo Lin School of Medicine (J.K.W.L.), National University of Singapore, Singapore; Health and Social Sciences, Singapore Institute of Technology, Singapore (X.R.T.); Campus for Research Excellence and Technological Enterprise, Singapore (S.H.G., J.K.W.L.); Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore (M.K.S.L.); Duke-National University of Singapore Medical School, Singapore (M.K.S.L.); Department of Endocrinology, Division of Medicine, Tan Tock Seng Hospital, Singapore (M.K.S.L.); Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore (M.K.S.L., J.G.E.); Folkhalsan Research Center, Helsinki, Finland (J.G.E.); Department of General Practice and Primary Health Care, University of Helsinki, and Helsinki University Hospital, University of Helsinki, Helsinki, Finland (J.G.E.); and Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore (J.G.E.)
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Bartlett MF, Akins JD, Oneglia A, Brothers RM, Wilkes D, Nelson MD. Impact of Cutaneous Blood Flow on NIR-DCS Measures of Skeletal Muscle Blood Flow Index. J Appl Physiol (1985) 2021; 131:914-926. [PMID: 34264131 DOI: 10.1152/japplphysiol.00337.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an optical technique for estimating relative changes in skeletal muscle perfusion during exercise, but may be affected by changes in cutaneous blood flow, as photons emitted by the laser must first pass through the skin. Accordingly, the purpose of this investigation was to examine how increased cutaneous blood flow affects NIR-DCS blood flow index (BFI) at rest and during exercise using a passive whole-body heating protocol that increases cutaneous, but not skeletal muscle, perfusion in the uncovered limb. BFI and cutaneous perfusion (laser Doppler flowmetry) were assessed in 15 healthy young subjects before (e.g., rest) and during 5-minutes of moderate-intensity hand-grip exercise in normothermic conditions and after cutaneous blood flow was elevated via whole-body heating. Hyperthermia significantly increased both cutaneous perfusion (~7.3-fold; p≤0.001) and NIR-DCS BFI (~4.5-fold; p≤0.001). Although relative BFI (i.e., fold-change above baseline) exhibited a typical exponential increase in muscle perfusion during normothermic exercise (2.81±0.95), there was almost no change in BFI during hyperthermic exercise (1.43±0.44). A subset of 8 subjects were subsequently treated with intradermal injection of botulinum toxin-A (Botox) to block heating-induced elevations in cutaneous blood flow, which 1) nearly abolished the hyperthermia-induced increase in BFI, and 2) restored BFI kinetics during hyperthermic exercise to values that were not different from normothermic exercise (p=0.091). Collectively, our results demonstrate that cutaneous blood flow can have a substantial, detrimental impact on NIR-DCS estimates of skeletal muscle perfusion and highlight the need for technical and/or pharmacological advancements to overcome this issue moving forward.
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Affiliation(s)
- Miles F Bartlett
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, United States
| | - John D Akins
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, United States
| | - Andrew Oneglia
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, United States
| | - R Matthew Brothers
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, United States
| | - Dustin Wilkes
- Medical City Weatherford Dermatology Residency Program, Weatherford, TX, United States
| | - Michael D Nelson
- Department of Kinesiology, The University of Texas at Arlington, Arlington, TX, United States
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Limberg JK, Casey DP, Trinity JD, Nicholson WT, Wray DW, Tschakovsky ME, Green DJ, Hellsten Y, Fadel PJ, Joyner MJ, Padilla J. Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology. Am J Physiol Heart Circ Physiol 2019; 318:H301-H325. [PMID: 31886718 DOI: 10.1152/ajpheart.00649.2019] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,François M. Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | | | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Western Australia, Australia
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | | | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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Laitano O, Leon LR, Roberts WO, Sawka MN. Controversies in exertional heat stroke diagnosis, prevention, and treatment. J Appl Physiol (1985) 2019; 127:1338-1348. [DOI: 10.1152/japplphysiol.00452.2019] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
During the past several decades, the incidence of exertional heat stroke (EHS) has increased dramatically. Despite an improved understanding of this syndrome, numerous controversies still exist within the scientific and health professions regarding diagnosis, pathophysiology, risk factors, treatment, and return to physical activity. This review examines the following eight controversies: 1) reliance on core temperature for diagnosing and assessing severity of EHS; 2) hypothalamic damage induces heat stroke and this mediates “thermoregulatory failure” during the immediate recovery period; 3) EHS is a predictable condition primarily resulting from overwhelming heat stress; 4) heat-induced endotoxemia mediates systemic inflammatory response syndrome in all EHS cases; 5) nonsteroidal anti-inflammatory drugs for EHS prevention; 6) EHS shares similar mechanisms with malignant hyperthermia; 7) cooling to a specific body core temperature during treatment for EHS; and 8) return to physical activity based on physiological responses to a single-exercise heat tolerance test. In this review, we present and discuss the origins and the evidence for each controversy and propose next steps to resolve the misconception.
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Affiliation(s)
- Orlando Laitano
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Lisa R. Leon
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - William O. Roberts
- Department of Family Medicine and Community Health, University of Minnesota Twin Cities, Minneapolis, Minnesota
| | - Michael N. Sawka
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia
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Francisco MA, Minson CT. Cutaneous active vasodilation as a heat loss thermoeffector. HANDBOOK OF CLINICAL NEUROLOGY 2019; 156:193-209. [PMID: 30454590 DOI: 10.1016/b978-0-444-63912-7.00012-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Human skin is the interface between the human body and the environment. As such, human temperature regulation relies largely on cutaneous vasomotor and sudomotor adjustments to appropriately thermoregulate. In particular, changes in skin blood flow can increase or decrease the convective heat transfer from internal tissues to the periphery where it can increase or prevent heat loss to the environment. Thermoregulatory control of the cutaneous vasculature is largely due to cutaneous sympathetic nerves. Sympathetic adrenergic nerves mediate vasoconstriction of the skin, similar to other vascular beds, whereas active vasodilator nerves in nonglabrous skin respond to changes in internal and peripheral temperatures and can profoundly increase skin blood flow. Activation of these vasodilator nerves is known as cutaneous active vasodilation and has been the subject of much recent research. This research has uncovered a highly complex system that involves the activation of multiple receptors and vasodilator pathways in a synergistic and sometimes redundant manner. This complexity and redundancy has left our understanding of cutaneous active vasodilation incomplete; however, the employment of new techniques and use of new pharmacologic agents have introduced many new insights into cutaneous active vasodilation.
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Affiliation(s)
- Michael A Francisco
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Christopher T Minson
- Department of Human Physiology, University of Oregon, Eugene, OR, United States.
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Kenney WL. Edward F. Adolph Distinguished Lecture: Skin-deep insights into vascular aging. J Appl Physiol (1985) 2017; 123:1024-1038. [PMID: 28729391 DOI: 10.1152/japplphysiol.00589.2017] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 11/22/2022] Open
Abstract
The skin is an accessible model circulation for studying vascular function and dysfunction across the lifespan. Age-related changes, as well as those associated with disease progression, often appear first in the cutaneous circulation. Furthermore, impaired vascular signaling and attendant endothelial dysfunction, the earliest indicators of cardiovascular pathogenesis, occur in a similar fashion across multiple tissue beds throughout the body, including the skin. Because microvascular dysfunction is a better predictor of long-term outcomes and adverse cardiovascular events than is large vessel disease, an understanding of age-associated changes in the control of the human cutaneous microcirculation is important. This review focuses on 1) the merits of using skin-specific methods and techniques to study vascular function, 2) microvascular changes in aged skin (in particular, the role of the endothelial-derived dilator nitric oxide), and 3) the impact of aging on heat-induced changes in skin vasodilation. While skin blood flow is controlled by multiple, often redundant, mechanisms, our laboratory has used a variety of distinct thermal provocations of this model circulation to isolate specific age-associated changes in vascular function. Skin-specific approaches and techniques, such as intradermal microdialysis coupled with laser-Doppler flowmetry (in vivo) and biochemical analyses of skin biopsy samples (in vitro), have allowed for the targeted pharmacodissection of the mechanistic pathways controlling skin vasoreactivity and study of the impact of aging and disease states. Aged skin has an attenuated ability to vasodilate in response to warm stimuli and to vasoconstrict in response to cold stimuli.
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Affiliation(s)
- W Larry Kenney
- Department of Kinesiology and Intercollege Graduate Program in Physiology, Noll Laboratory, The Pennsylvania State University, University Park, Pennsylvania
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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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McEntire SJ, Reis SE, Suman OE, Hostler D. Effects of Low-Dose Aspirin Therapy on Thermoregulation in Firefighters. Saf Health Work 2015; 6:256-62. [PMID: 26929836 PMCID: PMC4674504 DOI: 10.1016/j.shaw.2015.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 06/11/2015] [Accepted: 06/12/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Heart attack is the most common cause of line-of-duty death in the fire service. Daily aspirin therapy is a preventative measure used to reduce the morbidity of heart attacks but may decrease the ability to dissipate heat by reducing skin blood flow. METHODS In this double-blind, placebo-controlled, crossover study, firefighters were randomized to receive 14 days of therapy (81-mg aspirin or placebo) before performing treadmill exercise in thermal-protective clothing in a hot room [38.8 ± 2.1°C, 24.9 ± 9.1% relative humidity (RH)]. Three weeks without therapy was provided before crossing to the other arm. Firefighters completed a baseline skin blood-flow assessment via laser Doppler flowmetry; skin was heated to 44°C to achieve maximal cutaneous vasodilation. Skin blood flow was measured before and after exercise in a hot room, and at 0 minutes, 10 minutes, 20 minutes, and 30 minutes of recovery under temperature conditions (25.3 ± 1.2°C, 40.3 ± 13.7% RH). Platelet clotting time was assessed before drug administration, and before and after exercise. RESULTS Fifteen firefighters completed the study. Aspirin increased clotting time before and after exercise compared with placebo (p = 0.003). There were no differences in absolute skin blood flow between groups (p = 0.35). Following exercise, cutaneous vascular conductance (CVC) was 85 ± 42% of maximum in the aspirin and 76 ± 37% in the placebo groups. The percentage of maximal CVC did not differ by treatment before or after recovery. Neither maximal core body temperature nor heart rate responses to exercise differed between trials. CONCLUSION There were no differences in skin blood flow during uncompensable heat stress following exercise after aspirin or placebo therapy.
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Affiliation(s)
- Serina J. McEntire
- Department of Exercise Physiology College of Nursing and Health Sciences, Valdosta State University, Valdosta, GA, USA
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Steven E. Reis
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Oscar E. Suman
- Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA
| | - David Hostler
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Exercise and Nutrition Sciences, University of Buffalo, Buffalo, NY, USA
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Kenney WL, Craighead DH, Alexander LM. Heat waves, aging, and human cardiovascular health. Med Sci Sports Exerc 2015; 46:1891-9. [PMID: 24598696 DOI: 10.1249/mss.0000000000000325] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This brief review is based on a President's Lecture presented at the Annual Meeting of the American College of Sports Medicine in 2013. The purpose of this review was to assess the effects of climate change and consequent increases in environmental heat stress on the aging cardiovascular system. The earth's average global temperature is slowly but consistently increasing, and along with mean temperature changes come increases in heat wave frequency and severity. Extreme passive thermal stress resulting from prolonged elevations in ambient temperature and prolonged physical activity in hot environments creates a high demand on the left ventricle to pump blood to the skin to dissipate heat. Even healthy aging is accompanied by altered cardiovascular function, which limits the extent to which older individuals can maintain stroke volume, increase cardiac output, and increase skin blood flow when exposed to environmental extremes. In the elderly, the increased cardiovascular demand during heat waves is often fatal because of increased strain on an already compromised left ventricle. Not surprisingly, excess deaths during heat waves 1) occur predominantly in older individuals and 2) are overwhelmingly cardiovascular in origin. Increasing frequency and severity of heat waves coupled with a rapidly growing at-risk population dramatically increase the extent of future untoward health outcomes.
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Affiliation(s)
- W Larry Kenney
- Department of Kinesiology, Pennsylvania State University, University Park, PA
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Carter SJ, Herron RL, Akers SZ, Bishop PA. Acetylsalicylic acid does not alter thermo-effector responses during mild whole-body passive heat stress in young men. Int J Hyperthermia 2015; 31:319-24. [PMID: 25697227 DOI: 10.3109/02656736.2014.999721] [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: 11/13/2022] Open
Abstract
Acetylsalicylic acid (ASA), aspirin, exerts potent systemic effects that may interfere with normal thermo-effector responses. We investigated the influence of commonly ingested ASA doses on measures of skin blood flow (SkBF) and local sweat rate (SR) during whole-body, passive heat stress. Seven male participants completed counter-balanced trials to compare ASA treatments (single dose 325 mg or 4 consecutive days 81 mg (4-d 81 mg)) to control (no ASA). Laser-Doppler flowmetry provided an index of SkBF. A ventilated capsule measured local sweat rate via capacitance hygrometry. Mean body temperature ([Formula: see text]) was increased by 1 °C above baseline using a water-perfused suit. [Formula: see text] was similar at the onset of cutaneous vasodilation among trials. Cutaneous vascular conductance, expressed as a percentage change from baseline, was not different among trials. Additionally, [Formula: see text] at the onset of local SR and SR sensitivity did not differ among trials. While ASA has previously been shown to influence SkBF during heat stress, it is possible our cohort's relatively young age may have contributed to our dissimilar results.
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Affiliation(s)
- Stephen J Carter
- Department of Kinesiology, University of Alabama , Tuscaloosa , Alabama
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Johnson JM, Minson CT, Kellogg DL. Cutaneous vasodilator and vasoconstrictor mechanisms in temperature regulation. Compr Physiol 2014; 4:33-89. [PMID: 24692134 DOI: 10.1002/cphy.c130015] [Citation(s) in RCA: 241] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In this review, we focus on significant developments in our understanding of the mechanisms that control the cutaneous vasculature in humans, with emphasis on the literature of the last half-century. To provide a background for subsequent sections, we review methods of measurement and techniques of importance in elucidating control mechanisms for studying skin blood flow. In addition, the anatomy of the skin relevant to its thermoregulatory function is outlined. The mechanisms by which sympathetic nerves mediate cutaneous active vasodilation during whole body heating and cutaneous vasoconstriction during whole body cooling are reviewed, including discussions of mechanisms involving cotransmission, NO, and other effectors. Current concepts for the mechanisms that effect local cutaneous vascular responses to local skin warming and cooling are examined, including the roles of temperature sensitive afferent neurons as well as NO and other mediators. Factors that can modulate control mechanisms of the cutaneous vasculature, such as gender, aging, and clinical conditions, are discussed, as are nonthermoregulatory reflex modifiers of thermoregulatory cutaneous vascular responses.
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Affiliation(s)
- John M Johnson
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
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12
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Hostler D, Suyama J, Guyette FX, Moore CG, Pryor RR, Khorana P, McEntire SJ, Comer D, Reis SE. A Randomized Controlled Trial of Aspirin and Exertional Heat Stress Activation of Platelets in Firefighters during Exertion in Thermal Protective Clothing. PREHOSP EMERG CARE 2014; 18:359-67. [DOI: 10.3109/10903127.2013.869644] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Decorps J, Saumet JL, Sommer P, Sigaudo-Roussel D, Fromy B. Effect of ageing on tactile transduction processes. Ageing Res Rev 2014; 13:90-9. [PMID: 24373814 DOI: 10.1016/j.arr.2013.12.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 12/02/2013] [Accepted: 12/16/2013] [Indexed: 01/09/2023]
Abstract
With advancing age, a decline in the main sensory modalities including touch sensation and perception is well reported to occur. This review mainly outlines the peripheral components of touch perception highlighting ageing influences on morphological and functional features of cutaneous mechanical transducers and mechanosensitive ion channels, sensory innervation, neurotransmitters and even vascular system required to ensure efferent function of the afferent nerve fibres in the skin. This, in conjunction with effect of ageing on the skin per se and central nervous system, could explain the tactile deficit seen among the ageing population. We also discuss appropriate tools and experimental models available to study the age-related tactile decline.
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Affiliation(s)
- Johanna Decorps
- Laboratory of Tissue Biology and Therapeutic Engineering, Centre National de la Recherche Scientifique (CNRS) UMR 5305, Lyon, France; University of Lyon 1, UMR 5305, Lyon, France.
| | - Jean Louis Saumet
- Laboratory of Tissue Biology and Therapeutic Engineering, Centre National de la Recherche Scientifique (CNRS) UMR 5305, Lyon, France; University of Lyon 1, UMR 5305, Lyon, France.
| | - Pascal Sommer
- Laboratory of Tissue Biology and Therapeutic Engineering, Centre National de la Recherche Scientifique (CNRS) UMR 5305, Lyon, France; University of Lyon 1, UMR 5305, Lyon, France.
| | - Dominique Sigaudo-Roussel
- Laboratory of Tissue Biology and Therapeutic Engineering, Centre National de la Recherche Scientifique (CNRS) UMR 5305, Lyon, France; University of Lyon 1, UMR 5305, Lyon, France.
| | - Berengere Fromy
- Laboratory of Tissue Biology and Therapeutic Engineering, Centre National de la Recherche Scientifique (CNRS) UMR 5305, Lyon, France; University of Lyon 1, UMR 5305, Lyon, France.
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Bruning RS, Dahmus JD, Kenney WL, Alexander LM. Aspirin and clopidogrel alter core temperature and skin blood flow during heat stress. Med Sci Sports Exerc 2013; 45:674-82. [PMID: 23135368 DOI: 10.1249/mss.0b013e31827981dc] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
UNLABELLED Antithrombotic therapy with oral aspirin (ASA) or clopidogrel (CLO) (Plavix; Bristol-Myers Squibb, Bridgewater, NJ) is associated with an attenuated skin vasodilator response and a greater rate of rise in core temperature in healthy, middle-age individuals during passive heating in a water perfused suit. PURPOSE The present double-blind, crossover study examined the functional consequences of 7 d of low-dose ASA (81 mg·d) versus CLO (75 mg·d) treatment in 14 healthy, middle-age (50-65 yr) men and women during passive heating in air (40 min at 30°C, 40% relative humidity) followed by exercise (60% V˙O2peak). METHODS Oral temperature (Tor) was measured in the antechamber (23.0°C ± 0.1°C) before entering a warm environmental chamber. After 40 min of rest, subjects cycled on a recumbent cycle ergometer for up to 120 min. Esophageal temperature (Tes) and laser Doppler flux were measured continuously, and the latter was normalized to maximal cutaneous vascular conductance (%CVCmax). RESULTS Before entry into the environmental chamber there were no differences in Tor among treatments; however, after 40 min of rest in the heat, Tes was significantly higher for ASA and CLO versus placebo (37.2°C ± 0.1°C, 37.3°C ± 0.1°C, vs 37.0°C ± 0.1°C, both P < 0.001), a difference that persisted throughout exercise (P < 0.001 vs placebo). The mean body temperature thresholds for the onset of cutaneous vasodilation were shifted to the right for both ASA and CLO during exercise (P < 0.05). CONCLUSION ASA and CLO resulted in elevated core temperatures during passive heat stress and shifted the onset of peripheral thermoeffector mechanisms toward higher body temperatures during exercise heat stress.
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Affiliation(s)
- Rebecca S Bruning
- Noll Laboratory, Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802, USA
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15
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Blann AD, Kuzniatsova N, Lip GYH. Vascular and platelet responses to aspirin in patients with coronary artery disease. Eur J Clin Invest 2013. [PMID: 23198725 DOI: 10.1111/eci.12021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Variability in the response to aspirin (sometimes known as aspirin resistance) in modulating platelet activity is a potentially important clinical issue in coronary artery disease (CAD), but may be also be important in other areas of pathophysiology. MATERIALS AND METHODS Testing the hypothesis of a relationship between aspirin resistance and vascular function, inflammation and coagulation, we recruited 175 stable CAD outpatients taking 75 mg aspirin daily. Indices were compared to 58 controls not taking aspirin. Platelet activity was assessed by light transmission aggregometry (LTA) to 0·5 mg/mL arachidonic acid (AA), plasma markers soluble P selectin and thromboxane (ELISA), and resting and AA stimulated membrane P selectin and PAC-1 expression (flow cytometry). Vascular function was assessed by arterial stiffness (Sphygmocor system), von Willebrand factor and soluble E selectin (ELISA), inflammation by high sensitivity CRP and interleukin-6, and coagulation by tissue factor and fibrin d-dimers levels (all immunoassay). RESULTS The 5-min LTA response AA was superior to flow cytometry in discriminating the response of platelets to aspirin. Using the cut-off of 20% LTA response to AA, 32·6% of patients were aspirin resistant. The latter had higher soluble P selectin (P = 0·03), CRP (P = 0·029) and fibrin d-dimers (P = 0·01) compared to those who were aspirin sensitive. There was no relationship between aspirin response status and any vascular index. CONCLUSION We conclude that LTA is a more sensitive marker of aspirin resistance than is flow cytometry for P-selectin and PCA-1, and that aspirin response has no influence on vascular function.
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Affiliation(s)
- Andrew D Blann
- Centre for Cardiovascular Sciences, University of Birmingham, Birmingham, UK.
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Bogie K, Powell HL, Ho CH. New concepts in the prevention of pressure sores. HANDBOOK OF CLINICAL NEUROLOGY 2012; 109:235-246. [PMID: 23098716 DOI: 10.1016/b978-0-444-52137-8.00014-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Pressure sores are a serious, and costly, complication for many patients with reduced mobility and sensation. Some populations, such as those with spinal cord injury (SCI), remain at high risk throughout their lifetime. Prevention is highly preferable and while the concept is readily definable, it is much more challenging to develop valid preventative measures. Subjective and objective approaches to risk factor assessment before pressure sores develop are reviewed, including risk status scales and emerging techniques to assess deep tissue injury. Devices to prevent pressure sores have traditionally focused on pressure-relieving cushions and mattresses. Technological advances being applied in the development of new pressure sore prevention devices are presented. Clinical evidence-based practice is integral to pressure sore prevention. Comprehensive assessment must include evaluation of systemic diseases, anatomical and physiological factors, together with environmental and psychosocial factors, which can all contribute to pressure sore development. Extrinsic factors need to be considered in conjunction with intrinsic tissue health factors and are reviewed together with an evaluation of currently available clinical practice guidelines. This chapter presents the broad diversity of factors associated with pressure sore development and highlights the need for an interdisciplinary team approach in order to maximize successful prevention of pressure sores.
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Affiliation(s)
- Kath Bogie
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, USA.
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17
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Murray LK, Otterstetter R, Muller MD, Glickman EL. The Effects of High- and Low-Dose Aspirin on Thermoregulation During and After Acute Cold Exposure. Wilderness Environ Med 2011; 22:321-5. [DOI: 10.1016/j.wem.2011.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 05/10/2011] [Accepted: 06/10/2011] [Indexed: 10/17/2022]
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Colberg SR, Hill LC, Parson HK, Thomas KS, Vinik AI. Aerobic training increases skin perfusion by a nitric oxide mechanism in type 2 diabetes. Diabetes Metab Syndr Obes 2010; 3:275-80. [PMID: 21437095 PMCID: PMC3047977 DOI: 10.2147/dmsott.s12136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
It is well known that a number of locally released vasodilatory and vasoconstrictive compounds can affect skin perfusion. This study investigated the effects of aerobic training on the contribution of nitric oxide (NO), prostaglandins (PG), and endothelial-derived hyperpolarizing factor (EDHF) in stimulated dorsal foot skin perfusion in individuals with type 2 diabetes (T2DM). Ten previously sedentary, older individuals with T2DM (57.0 ± 3.1 years) and nine sedentary controls (53.5 ± 3.2 years) were tested before and after undertaking six months of moderate aerobic training three times weekly in a supervised setting. All subjects underwent measurement of baseline (32°C) and heat-stimulated (40°C and 44°C) dorsal foot skin perfusion starting one hour after ingestion of a single, oral 325 mg dose of aspirin, a known inhibitor of PG synthesis. Before aspirin ingestion, a subcutaneous microdialysis probe was inserted into each foot dorsum to administer either saline (PG pathway only blocked by aspirin in the left foot) or L-NAME (N(G)-nitro-l-arginine methyl ester; thereby inhibiting both PG and NO pathways in the right foot). Normative data collected previously on subjects undergoing saline administration via microdialysis without aspirin ingestion served as a control group. Significantly lower responsiveness of maximal perfusion was found with the EDHF pathway alone unblocked compared with NO and EDHF unblocked after training. Maximal suppression attributable directly to NO, PG, and EDHF was not significantly different when examined by subject group and training status. However, contributions of NO, PG, and EDHF to maximal perfusion were significantly increased, decreased, and unchanged by aerobic training, respectively, with diabetic and control subjects combined due to nonsignificant differences between groups. Improvements in maximally stimulated dorsal foot skin perfusion resulting from six months of aerobic training appear to have primarily an NO basis, with lesser contributions from PG following training, regardless of diabetes status.
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Affiliation(s)
- Sheri R Colberg
- Old Dominion University, Norfolk, Virginia, USA
- Correspondence: Sheri Colberg, Human Movement Sciences Department, Old Dominion University, Norfolk, VA 23529, USA, Tel +1 757 683 3356, Fax +1 757 683 4270, Email
| | - Laura C Hill
- State University of New York at Cortland, New York, USA
| | | | | | - Aaron I Vinik
- Eastern Virginia Medical School, Norfolk, Virginia, USA
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Holowatz LA, Kenney WL. Peripheral mechanisms of thermoregulatory control of skin blood flow in aged humans. J Appl Physiol (1985) 2010; 109:1538-44. [PMID: 20413421 DOI: 10.1152/japplphysiol.00338.2010] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human skin blood flow is controlled via dual innervation from the sympathetic nervous system. Reflex cutaneous vasoconstriction and vasodilation are both impaired with primary aging, rendering the aged more vulnerable to hypothermia and cardiovascular complications from heat-related illness. Age-related alterations in the thermoregulatory control of skin blood flow occur at multiple points along the efferent arm of the reflex, including 1) diminished sympathetic outflow, 2) altered presynaptic neurotransmitter synthesis, 3) reduced vascular responsiveness, and 4) impairments in downstream (endothelial and vascular smooth muscle) second-messenger signaling. This mechanistic review highlights some of the recent findings in the area of aging and the thermoregulatory control of skin blood flow.
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Affiliation(s)
- Lacy A Holowatz
- Department of Kinesiology, The Pennsylvania State University, Noll Laboratory, University Park, PA 16802, USA.
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Holowatz LA, Jennings JD, Lang JA, Kenney WL. Systemic low-dose aspirin and clopidogrel independently attenuate reflex cutaneous vasodilation in middle-aged humans. J Appl Physiol (1985) 2010; 108:1575-81. [PMID: 20360429 DOI: 10.1152/japplphysiol.01362.2009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Chronic systemic platelet cyclooxygenase (COX) inhibition with low-dose aspirin [acetylsalicylic acid (ASA)] significantly attenuates reflex cutaneous vasodilation in middle-aged humans, whereas acute, localized, nonisoform-specific inhibition of vascular COX with intradermal administration of ketorolac does not alter skin blood flow during hyperthermia. Taken together, these data suggest that platelets may be involved in reflex cutaneous vasodilation, and this response is inhibited with systemic pharmacological platelet inhibition. We hypothesized that, similar to ASA, specific platelet ADP receptor inhibition with clopidogrel would attenuate reflex vasodilation in middle-aged skin. In a double-blind crossover design, 10 subjects (53+/-2 yr) were instrumented with four microdialysis fibers for localized drug administration and heated to increase body core temperature [oral temperature (Tor)] 1 degrees C during no systemic drug (ND), and after 7 days of systemic ASA (81 mg) and clopidogrel (75 mg) treatment. Skin blood flow (SkBF) was measured using laser-Doppler flowmetry over each site assigned as 1) control, 2) nitric oxide synthase inhibited (NOS-I; 10 mM NG-nitro-L-arginine methyl ester), 3) COX inhibited (COX-I; 10 mM ketorolac), and 4) NOS-I+COX-I. Data were normalized and presented as a percentage of maximal cutaneous vascular conductance (%CVCmax; 28 mM sodium nitroprusside+local heating to 43 degrees C). During ND conditions, SkBF with change (Delta) in Tor=1.0 degrees C was 56+/-3% CVCmax. Systemic low-dose ASA and clopidogrel both attenuated reflex vasodilation (ASA: 43+/-3; clopidogrel: 32+/-3% CVCmax; both P<0.001). In all trials, localized COX-I did not alter SkBF during significant hyperthermia (ND: 56+/-7; ASA: 43+/-5; clopidogrel: 35+/-5% CVCmax; all P>0.05). NOS-I attenuated vasodilation in ND and ASA (ND: 28+/-6; ASA: 25+/-4% CVCmax; both P<0.001), but not with clopidogrel (27+/-4% CVCmax; P>0.05). NOS-I+COX-I was not different compared with NOS-I alone in either systemic treatment condition. Both systemic ASA and clopidogrel reduced the time required to increase Tor 1 degrees C (ND: 58+/-3 vs. ASA: 45+/-2; clopidogrel: 39+/-2 min; both P<0.001). ASA-induced COX and specific platelet ADP receptor inhibition attenuate reflex vasodilation, suggesting platelet involvement in reflex vasodilation through the release of vasodilating factors.
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Affiliation(s)
- Lacy A Holowatz
- Department of Kinesiology, The Pennsylvania State University, 113 Noll Lab, Univ. Park, PA 16802, USA.
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Hodges GJ, Johnson JM. Adrenergic control of the human cutaneous circulation. Appl Physiol Nutr Metab 2009; 34:829-39. [DOI: 10.1139/h09-076] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cutaneous circulation is influenced by a variety of thermoregulatory (skin and internal temperature-driven) and nonthermoregulatory (e.g., baroreflex, exercise-associated reflexes) challenges. The responses to these stimuli are brought about through vasoconstrictor nerves, vasodilator nerves, and changes in the local temperature of the vessels themselves. In this review, we examine how thermoregulatory influences mediate changes in skin blood flow through the sympathetic nervous system. We discuss cutaneous vascular responses to both local and whole-body heating and cooling and the mechanisms underlying these responses, with the overarching conclusion that sympathetic function plays significant roles in reflex vasoconstriction and vasodilatation and in the responses to both local cooling and local heating of the skin.
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Affiliation(s)
- Gary J. Hodges
- Department of Physiology, The University of Texas Health Science Center, San Antonio, TX 78229, USA
- School of Kinesiology, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - John M. Johnson
- Department of Physiology, The University of Texas Health Science Center, San Antonio, TX 78229, USA
- School of Kinesiology, The University of Western Ontario, London, ON N6A 3K7, Canada
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Holowatz LA, Jennings JD, Lang JA, Kenney WL. Ketorolac alters blood flow during normothermia but not during hyperthermia in middle-aged human skin. J Appl Physiol (1985) 2009; 107:1121-7. [PMID: 19661446 DOI: 10.1152/japplphysiol.00750.2009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In young healthy humans full expression of reflex cutaneous vasodilation is dependent on cyclooxygenase (COX)- and nitric oxide synthase (NOS)-dependent mechanisms. Chronic low-dose aspirin therapy attenuates reflex cutaneous vasodilation potentially through both platelet and vascular COX-dependent mechanisms. We hypothesized the contribution of COX-dependent vasodilators to reflex cutaneous vasodilation during localized acute COX inhibition would be attenuated in healthy middle-aged humans due to a shift toward COX-dependent vasoconstrictors. Four microdialysis fibers were placed in forearm skin of 13 middle-aged (53 +/- 2 yr) normotensive healthy humans, serving as control (Ringer), COX-inhibited (10 mM ketorolac), NOS-inhibited (10 mM N(G)-nitro-l-arginine methyl ester), and combined NOS- and COX-inhibited sites. Red blood cell flux was measured over each site by laser-Doppler flowmetry as reflex vasodilation was induced by increasing oral temperature (T(or)) 1.0 degrees C using a water-perfused suit. Cutaneous vascular conductance was calculated (CVC = flux/mean arterial pressure) and normalized to maximal CVC (CVC(max); 28 mM sodium nitroprusside). CVC(max) was not affected by localized microdialysis drug treatment (P > 0.05). Localized COX inhibition increased baseline (18 +/- 3%CVC(max); P < 0.001) compared with control (9 +/- 1%CVC(max)), NOS-inhibited (7 +/- 1%CVC(max)), and combined sites (10 +/- 1%CVC(max)). %CVC(max) in the COX-inhibited site remained greater than the control site with DeltaT(or) < or = 0.3 degrees C; however, there was no difference between these sites with DeltaT(or) > or = 0.4 degrees C. NOS inhibition and combined COX and NOS inhibition attenuated reflex vasodilation compared with control (P < 0.001), but there was no difference between these sites. Localized COX inhibition with ketorolac significantly augments baseline CVC but does not alter the subsequent skin blood flow response to hyperthermia, suggesting a limited role for COX-derived vasodilator prostanoids in reflex cutaneous vasodilation and a shift toward COX-derived vasoconstrictors in middle-aged human skin.
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Affiliation(s)
- Lacy A Holowatz
- Department of Kinesiology, The Pennsylvania State University, Noll Laboratory,University Park, Pennsylvania, USA.
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23
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Holowatz LA, Kenney WL. Reply to Mahe, Rousseau, Saumet, and Abraham. J Appl Physiol (1985) 2009. [DOI: 10.1152/japplphysiol.00038.2009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Mahe G, Rousseau P, Saumet JL, Abraham P. About “Chronic low-dose aspirin therapy attenuates reflex cutaneous vasodilatation in middle-aged humans”. J Appl Physiol (1985) 2009; 106:1471; author reply 1472. [DOI: 10.1152/japplphysiol.91653.2008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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