1
|
Wang S, Lei Y, Li Wang X, Ma K, Wang C, Sun C, Han T. Association between temperatures and type 2 diabetes: A prospective study in UK Biobank. Diabetes Res Clin Pract 2024; 215:111817. [PMID: 39128563 DOI: 10.1016/j.diabres.2024.111817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 08/04/2024] [Accepted: 08/08/2024] [Indexed: 08/13/2024]
Abstract
OBJECTIVE This study aims to prospectively examine the association between temperatures and the occurrence of type 2 diabetes (T2D). METHODS We used the CPH models to analyze 103,215 non-diabetic participants in the UK Biobank cohort who answered questions about workplace temperature, to evaluate the survival relationship, and the interaction effects of working environmental temperature and T2D-related genetic risk scores (GRS) on the occurrence of T2D. The occurrence of T2D was assessed by hospital inpatient records. The weighted T2D-related GRS were calculated. RESULTS During 1,355,200.6 person-years follow-up, a total of 2436 participants were documented as having diagnosed T2D. After adjustment, compared to the comfortable group, the participants working in non-comfortable environmental temperature had greater risk of T2D (HR: 1.27, 95 %CI: 1.04 to 1.55, for cold; HR: 1.32, 95 %CI: 1.17 to 1.48 for hot; HR: 1.51, 95 %CI: 1.38 to 1.65 for alternate). Similarly, individuals exposed to different levels of genetic risk scores in alternating hot and cold work environments had a higher risk of developing type 2 diabetes. CONCLUSIONS This study found working in single non-comfortable environmental temperatures was associated with greater risk of T2D occurrence, and exposure to alternating environmental temperatures had the highest risk of range and severity.
Collapse
Affiliation(s)
- ShengYuan Wang
- Department of Occupational Health, School of Public Health, Harbin Medical University, Harbin, PR China
| | - YaTing Lei
- Department of Occupational Health, School of Public Health, Harbin Medical University, Harbin, PR China
| | - Xiao Li Wang
- Department of Occupational Health, School of Public Health, Harbin Medical University, Harbin, PR China
| | - Kun Ma
- Department of Hygiene Toxicology, School of Public Health, Harbin Medical University, Harbin, PR China
| | - Cheng Wang
- Department of Environmental Health, School of Public Health, Harbin Medical University, Harbin, PR China
| | - ChangHao Sun
- National Key Discipline, Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, Harbin, Heilongjiang Province 150081, PR China.
| | - TianShu Han
- National Key Discipline, Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, Harbin, Heilongjiang Province 150081, PR China.
| |
Collapse
|
2
|
Hammond ST, Baumfalk DR, Parr SK, Butenas AL, Scheuermann BC, Turpin VRG, Behnke BJ, Hashmi MH, Ade CJ. Impaired microvascular reactivity in patients treated with 5-fluorouracil chemotherapy regimens: Potential role of endothelial dysfunction. IJC HEART & VASCULATURE 2023; 49:101300. [PMID: 38173789 PMCID: PMC10761309 DOI: 10.1016/j.ijcha.2023.101300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/27/2023] [Accepted: 11/06/2023] [Indexed: 01/05/2024]
Abstract
Background 5-fluorouracil (5-FU) is the second most common cancer chemotherapy associated with short- and long-term cardiotoxicity. Although the mechanisms mediating these toxicities are not well understood, patients often present with symptoms suggestive of microvascular dysfunction. We tested the hypotheses that patients undergoing cancer treatment with 5-FU based chemotherapy regimens would present with impaired microvascular reactivity and that these findings would be substantiated by decrements in endothelial nitric oxide synthase (eNOS) gene expression in 5-FU treated human coronary artery endothelial cells (HCAEC). Methods We first performed a cross-sectional analysis of 30 patients undergoing 5-FU based chemotherapy treatment for cancer (5-FU) and 32 controls (CON) matched for age, sex, body mass index, and prior health history (excluding cancer). Cutaneous microvascular reactivity was evaluated by laser Doppler flowmetry in response to endothelium-dependent (local skin heating; acetylcholine iontophoresis, ACh) and -independent (sodium nitroprusside iontophoresis, SNP) stimuli. In vitro experiments in HCAEC were completed to assess the effects of 5-FU on eNOS gene expression. Results 5-FU presented with diminished microvascular reactivity following eNOS-dependent local heating compared to CON (P = 0.001). Iontophoresis of the eNOS inhibitor L-NAME failed to alter the heating response in 5-FU (P = 0.95), despite significant reductions in CON (P = 0.03). These findings were corroborated by lower eNOS gene expression in 5-FU treated HCAEC (P < 0.01) compared to control. Peak vasodilation to ACh (P = 0.58) nor SNP (P = 0.39) were different between groups. Conclusions The present findings suggest diminished microvascular function along the eNOS-NO vasodilatory pathway in patients with cancer undergoing treatment with 5-FU-based chemotherapy regimens and thus, may provide insight into the underlying mechanisms of 5-FU cardiotoxicity.
Collapse
Affiliation(s)
- Stephen T. Hammond
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
- Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Shannon K. Parr
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Alec L.E. Butenas
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | | | | | - Bradley J. Behnke
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
- Johnson Cancer Research Center, Kansas State University, Manhattan, KS, USA
| | | | - Carl J. Ade
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA
- Johnson Cancer Research Center, Kansas State University, Manhattan, KS, USA
- Physicians Associates Studies, Kansas State University, Manhattan, KS, USA
| |
Collapse
|
3
|
Marcinkevics Z, Rubins U, Aglinska A, Logina I, Glazunovs D, Grabovskis A. Contactless photoplethysmography for assessment of small fiber neuropathy. Front Physiol 2023; 14:1180288. [PMID: 37727661 PMCID: PMC10505793 DOI: 10.3389/fphys.2023.1180288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 08/02/2023] [Indexed: 09/21/2023] Open
Abstract
Chronic pain is a prevalent condition affecting approximately one-fifth of the global population, with significant impacts on quality of life and work productivity. Small fiber neuropathies are a common cause of chronic pain, and current diagnostic methods rely on subjective self-assessment or invasive skin biopsies, highlighting the need for objective noninvasive assessment methods. The study aims to develop a modular prototype of a contactless photoplethysmography system with three spectral bands (420, 540, and 800 nm) and evaluate its potential for assessing peripheral neuropathy patients via a skin topical heating test and spectral analyses of cutaneous flowmotions. The foot topical skin heating test was conducted on thirty volunteers, including fifteen healthy subjects and fifteen neuropathic patients. Four cutaneous nerve fiber characterizing parameters were evaluated at different wavelengths, including vasomotor response trend, flare area, flare intensity index, and the spectral power of cutaneous flowmotions. The results show that neuropathic patients had significantly lower vasomotor response (50%), flare area (63%), flare intensity index (19%), and neurogenic component (54%) of cutaneous flowmotions compared to the control group, independent of photoplethysmography spectral band. An absolute value of perfusion was 20%-30% higher in the 420 nm band. Imaging photoplethysmography shows potential as a cost-effective alternative for objective and non-invasive assessment of neuropathic patients, but further research is needed to enhance photoplethysmography signal quality and establish diagnostic criteria.
Collapse
Affiliation(s)
- Zbignevs Marcinkevics
- Department of Human and Animal Physiology, Faculty of Biology, University of Latvia, Riga, Latvia
- Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga, Latvia
| | - Uldis Rubins
- Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga, Latvia
| | - Alise Aglinska
- Department of Human and Animal Physiology, Faculty of Biology, University of Latvia, Riga, Latvia
| | - Inara Logina
- Department of Neurology and Neurosurgery, Riga Stradins University, Riga, Latvia
| | - Dmitrijs Glazunovs
- Department of Neurology and Neurosurgery, Riga Stradins University, Riga, Latvia
| | - Andris Grabovskis
- Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Riga, Latvia
| |
Collapse
|
4
|
Tzen YT, Champagne PT, Rao V, Wang J, Tan WH, Klakeel M, Jain NB, Wukich DK, Koh TJ. Utilisation of skin blood flow as a precursor for pressure injury development in persons with acute spinal cord injury: A proof of concept. Int Wound J 2022; 19:2191-2199. [PMID: 35543296 DOI: 10.1111/iwj.13829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 11/28/2022] Open
Abstract
People with spinal cord injury (SCI) are at high risk of developing a pressure injury. It is unclear why some people with SCI develop pressure injury while others with similar predisposing risk factors do not during acute hospitalisation. This may hinder healthcare utilisation to prevent pressure injuries. The purpose of the study was to examine the proof-of-concept objective bedside skin blood flow measurements before a pressure injury develops in spinal cord injured patients during acute hospitalisation. This was an observational study. All participants had acute traumatic SCI and were pressure injury-free upon enrollment. Skin blood flow patterns were collected at both heels under two circumstances: localised pressure for reactive hyperemia, and localised heating for heat hyperemia. Our results showed that reactive and heat hyperemia were successfully induced in all eleven participants. Two participants developed pressure injury and nine did not have pressure injury at discharge. Heat hyperemia was smaller in participants with pressure injury. No difference was observed in reactive hyperemia between the groups. In conclusion, skin blood flow measurements could be obtained at bedside during acute hospitalisation of SCI for the purpose of research. Further examination of a larger group is warranted to determine clinical use of heat hyperemia pattern as predictor for pressure injury development.
Collapse
Affiliation(s)
- Yi-Ting Tzen
- Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, Texas, USA.,Department of Physical Medicine and Rehabilitation, UT Southwestern Medical Center, Dallas, Texas, USA.,Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Patricia T Champagne
- Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Varsha Rao
- Masters in Rehabilitation Science Program, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Physical Therapy, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Jijia Wang
- Department of Applied Clinical Research, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Wei-Han Tan
- Department of Physical Medicine and Rehabilitation, UT Southwestern Medical Center, Dallas, Texas, USA.,VA North Texas Health Care System, Dallas, Texas, USA
| | - Merrine Klakeel
- Department of Physical Medicine and Rehabilitation, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Nitin B Jain
- Department of Physical Medicine and Rehabilitation, UT Southwestern Medical Center, Dallas, Texas, USA.,Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Dane K Wukich
- Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Timothy J Koh
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois, USA
| |
Collapse
|
5
|
Pyevich M, Alexander LM, Stanhewicz AE. Women with a history of preeclampsia have preserved sensory nerve-mediated dilatation in the cutaneous microvasculature. Exp Physiol 2022; 107:175-182. [PMID: 34961978 PMCID: PMC8810741 DOI: 10.1113/ep090177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 12/20/2021] [Indexed: 02/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? Are sensory nerve-mediated vasodilatation and the NO-dependent contribution to that response attenuated in the cutaneous microvasculature of women who have had preeclampsia? What is the main finding and its importance? Women who have had preeclampsia demonstrate attenuated microvascular endothelium-dependent dilatation compared to women with a history of uncomplicated pregnancy. However, there are no differences in sensory nerve-mediated vasodilatation between groups. This suggests that the neurogenic response is not altered following preeclampsia, and that the NO-dependent vasodilatation of the neurogenic response is not related to endothelium-dependent NO-mediated dilatation in these women. ABSTRACT Women who have had preeclampsia (PE) demonstrate microvascular endothelial dysfunction, mediated in part by reduced nitric oxide (NO)-dependent mechanisms. Localized heating of the skin induces a biphasic vasodilatation response: a sensory nerve-mediated initial peak, followed by a sustained endothelium-dependent plateau. We have previously shown that the endothelium-dependent plateau is attenuated in PE. However, it is unknown if the sensory nerve-mediated initial peak is similarly attenuated. Therefore, the purpose of this study was to examine the effect of PE history on sensory nerve-mediated vasodilatation and the NO-dependent contribution to that response. We hypothesized that PE would have an attenuated initial peak and a reduced NO-dependent contribution to that response compared to women with a history of normotensive pregnancy (healthy controls, HC). Nine HC (31 ± 4 years) and nine PE (28 ± 6 years) underwent a standard local heating protocol (42°C; 0.1°C s-1 ). Two intradermal microdialysis fibres were placed in the skin of the ventral forearm for the continuous local delivery of lactated Ringer solution alone (control) or 15-mM NG -nitro-l-arginine methyl ester for nitric oxide synthase (NOS) inhibition. Red blood cell flux was measured at each site by laser Doppler flowmetry (LDF). Cutaneous vascular conductance was calculated (CVC = LDF/mean arterial pressure) and normalized to maximum (%CVCmax ; 28-mM SNP + local heat 43°C). There were no differences in the initial peak between groups (HC: 79 ± 8 vs. PE: 80 ± 10%CVCmax ; P = 0.936). NOS inhibition attenuated the initial peak in both HC (57 ± 18% CVCmax ; P = 0.003) and PE (54 ± 10%CVCmax ; P = 0.002). However, there were no differences in the NO-dependent portion of the initial peak (HC: 23 ± 16 vs. PE: 24 ± 9%; P = 0.777). The local heating plateau (HC: 99 ± 4 vs. PE: 88 ± 7%CVCmax ; P = 0.001) and NO contribution to the plateau (HC: 31 ± 9 vs. PE: 17 ± 14%; P = 0.02) were attenuated in PE. There was no relation between NO-dependent dilatation in the initial peak and NO-dependent dilatation in the plateau across groups (R2 = 0.005; P = 0.943). Women who have had PE demonstrate attenuated microvascular endothelium-dependent dilatation. However, there are no differences in sensory nerve-mediated vasodilatation following PE, suggesting that the NO-dependent vasodilatation of the neurogenic response is not related to endothelium-dependent NO-mediated dilatation in these women.
Collapse
Affiliation(s)
- Michael Pyevich
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA
| | - Lacy M Alexander
- Department of Kinesiology, Pennsylvania State University, University Park, PA
| | - Anna E. Stanhewicz
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA
| |
Collapse
|
6
|
Argarini R, Carter HH, Smith KJ, Naylor LH, McLaughlin RA, Green DJ. Adaptation to Exercise Training in Conduit Arteries and Cutaneous Microvessels in Humans: An Optical Coherence Tomography Study. Med Sci Sports Exerc 2021; 53:1945-1957. [PMID: 33731650 DOI: 10.1249/mss.0000000000002654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Exercise training has antiatherogenic effects on conduit and resistance artery function and structure in humans and induces angiogenic changes in skeletal muscle. However, training-induced adaptation in cutaneous microvessels is poorly understood, partly because of technological limitations. Optical coherence tomography (OCT) is a novel high-resolution imaging technique capable of visualizing cutaneous microvasculature at a resolution of ~30 μm. We utilized OCT to visualize the effects of training on cutaneous microvessels, alongside assessment of conduit artery flow-mediated dilation (FMD). METHODS We assessed brachial FMD and cutaneous microcirculatory responses at rest and in response to local heating and reactive hyperemia: pretraining and posttraining in eight healthy men compared with age-matched untrained controls (n = 8). Participants in the training group underwent supervised cycling at 80% maximal heart rate three times a week for 8 wk. RESULTS We found a significant interaction (P = 0.04) whereby an increase in FMD was observed after training (post 9.83% ± 3.27% vs pre 6.97% ± 1.77%, P = 0.01), with this posttraining value higher compared with the control group (6.9% ± 2.87%, P = 0.027). FMD was not altered in the controls (P = 0.894). There was a significant interaction for OCT-derived speed (P = 0.038) whereby a significant decrease in the local disk heating response was observed after training (post 98.6 ± 3.9 μm·s-1 vs pre 102 ± 5 μm·s-1, P = 0.012), whereas no changes were observed for OCT-derived speed in the control group (P = 0.877). Other OCT responses (diameter, flow rate, and density) to local heating and reactive hyperemia were unaffected by training. CONCLUSIONS Our findings suggest that vascular adaptation to exercise training is not uniform across all levels of the arterial tree; although exercise training improves larger artery function, this was not accompanied by unequivocal evidence for cutaneous microvascular adaptation in young healthy subjects.
Collapse
Affiliation(s)
| | - Howard H Carter
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, AUSTRALIA
| | | | - Louise H Naylor
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, AUSTRALIA
| | | | - Daniel J Green
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, AUSTRALIA
| |
Collapse
|
7
|
Marcinkevics Z, Aglinska A, Rubins U, Grabovskis A. Remote Photoplethysmography for Evaluation of Cutaneous Sensory Nerve Fiber Function. SENSORS 2021; 21:s21041272. [PMID: 33670087 PMCID: PMC7916836 DOI: 10.3390/s21041272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 11/23/2022]
Abstract
About 2% of the world’s population suffers from small nerve fiber dysfunction, neuropathy, which can result in severe pain. This condition is caused by damage to the small nerve fibers and its assessment is challenging, due to the lack of simple and objective diagnostic techniques. The present study aimed to develop a contactless photoplethysmography system using simple instrumentation, for objective and non-invasive assessment of small cutaneous sensory nerve fiber function. The approach is based on the use of contactless photoplethysmography for the characterization of skin flowmotions and topical heating evoked vasomotor responses. The feasibility of the technique was evaluated on volunteers (n = 14) using skin topical anesthesia, which is able to produce temporary alterations of cutaneous nerve fibers function. In the treated skin region in comparison to intact skin: neurogenic and endothelial component of flowmotions decreased by ~61% and 41%, the local heating evoked flare area decreased by ~44%, vasomotor response trend peak and nadir were substantially reduced. The results indicate for the potential of the remote photoplethysmography in the assessment of the cutaneous nerve fiber function. It is believed that in the future this technique could be used in the clinics as an affordable alternative to laser Doppler imaging technique.
Collapse
Affiliation(s)
- Zbignevs Marcinkevics
- Department of Human and Animal Physiology, Faculty of Biology, University of Latvia, Jelgavas St.1, LV-1004 Riga, Latvia
- Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Jelgavas St. 3, LV-1004 Riga, Latvia; (A.A.); (U.R.); (A.G.)
- Correspondence:
| | - Alise Aglinska
- Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Jelgavas St. 3, LV-1004 Riga, Latvia; (A.A.); (U.R.); (A.G.)
| | - Uldis Rubins
- Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Jelgavas St. 3, LV-1004 Riga, Latvia; (A.A.); (U.R.); (A.G.)
| | - Andris Grabovskis
- Biophotonics Laboratory, Institute of Atomic Physics and Spectroscopy, University of Latvia, Jelgavas St. 3, LV-1004 Riga, Latvia; (A.A.); (U.R.); (A.G.)
| |
Collapse
|
8
|
Sinusoidal changes in transcutaneous oxygen pressure, suggesting Cheyne-Stokes respiration, are frequent and of poor prognosis among patients with suspected critical limb ischemia. Atherosclerosis 2020; 316:15-24. [PMID: 33260007 DOI: 10.1016/j.atherosclerosis.2020.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/10/2020] [Accepted: 11/19/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND AIMS Transcutaneous oxygen pressure (TcpO2) is used in patients with suspected critical limb ischemia (CLI). Sinusoidal changes (SC~) in TcpO2 are found in patients with Cheyne-Stokes respiration (CSR). We aimed to determine the characteristics of TcpO2 changes at rest in patients with suspected CLI, define the objective criteria for SC ~ TcpO2 patterns (SC+), and estimate the prevalence of SC+ in our population and its impact on the outcome. METHODS We retrospectively analyzed 300 chest TcpO2 recordings performed in a 16-month period. We determined the presence/absence of SC ~ TcpO2 by visual analysis. We determined the acceptable error in the regularity of peaks of the cross-correlation with ROC curve analysis, among patients with typical SC ~ TcpO2 and non-sinusoidal patterns. Then, we defined SC + as a minimum of five peaks, a standard deviation of TcpO2 >1.25 mmHg, an error in regularity of peaks of the cross-correlation < 10%, and a cycle length between 30 and 100 s. In patients included until October 2019, we compared the outcome as a function of SC + or SC- with Cox models. RESULTS Mathematical detection of SC + found that 43 patients (14.3%) fulfilled all four defined criteria at the chest level, but only 23 did so at the limb level. In the follow-up of 207 patients, the presence of Sc ~ TcpO2 at the chest significantly increased the risk of mortality: hazard ratio: 2.69 [95%CI: 1.37-5.30]; p < 0.005. CONCLUSIONS SC ~ TcpO2 is frequent, and is associated with a poor outcome in patients with suspected CLI.
Collapse
|
9
|
Miller JT, Turner CG, Otis JS, Sebeh Y, Hayat MJ, Quyyumi AA, Wong BJ. Inhibition of iNOS augments cutaneous endothelial NO-dependent vasodilation in prehypertensive non-Hispanic Whites and in non-Hispanic Blacks. Am J Physiol Heart Circ Physiol 2020; 320:H190-H199. [PMID: 33124886 DOI: 10.1152/ajpheart.00644.2020] [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: 01/21/2023]
Abstract
We tested the hypothesis that inducible nitric oxide synthase (iNOS) contributes to reduced nitric oxide (NO)-dependent vasodilation in non-Hispanic Blacks and prehypertensive non-Hispanic Whites. Twenty Black and twenty White participants (10 normotensive, 10 prehypertensive per group; n = 40 total) participated in this study. Participants were instrumented with two microdialysis fibers, and each site was randomized as control (lactated Ringer) or iNOS inhibition (0.1 mM 1400W). Laser-Doppler flow probes and local heaters were used to measure skin blood flow and heat the skin to induce vasodilation, respectively. Each site was heated from 33°C to 39°C (rate: 0.1°C/s). Once a plateau was established, 20 mM nitro-l-arginine methyl ester (l-NAME), a nonspecific NOS inhibitor, was infused at each site to quantify NO-dependent vasodilation. At control sites, %NO-dependent vasodilation was reduced in prehypertensive Whites (47 ± 10%NO) and in both normotensive and prehypertensive Blacks (39 ± 9%NO and 28 ± 5%NO, respectively) relative to normotensive Whites (73 ± 8%NO; P < 0.0001 for all comparisons). Compared with respective control sites, iNOS inhibition increased NO-dependent vasodilation in prehypertensive Whites (68 ± 8%NO) and in both normotensive and prehypertensive Blacks (78 ± 8%NO and 55 ± 6%NO, respectively; P < 0.0001 for all comparisons). We failed to find an effect for normotensive Whites (77 ± 7%NO). After iNOS inhibition, %NO-dependent vasodilation was similar between normotensive Whites, prehypertensive Whites, and normotensive Blacks. Inhibition of iNOS increased NO-dependent vasodilation to a lesser extent in prehypertensive Blacks. These data suggest that iNOS contributes to reduced NO-dependent vasodilation in prehypertension and in Black participants.NEW & NOTEWORTHY Inducible nitric oxide synthase (iNOS) is typically upregulated in conditions of increased oxidative stress and may have detrimental effects on the vasculature. Endothelial nitric oxide (NO), which is cardioprotective, is reduced in prehypertensive non-Hispanic Whites and in non-Hispanic Blacks. We found that inhibition of iNOS can increase endothelial NO-dependent vasodilation in prehypertensive White participants and in both normotensive and prehypertensive Black participants.Inducible nitric oxide (NO) synthase (iNOS) can be upregulated under conditions of increased oxidative stress and may have detrimental effects on the vasculature. Endothelial NO, which is cardioprotective, is reduced in prehypertensive non-Hispanic Whites and in non-Hispanic Blacks. We found that inhibition of iNOS can increase endothelial NO-dependent vasodilation in prehypertensive White participants and in both normotensive and prehypertensive Black participants.
Collapse
Affiliation(s)
- James T Miller
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Casey G Turner
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Jeffrey S Otis
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Yesser Sebeh
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Matthew J Hayat
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Arshed A Quyyumi
- Emory Clinical Cardiovascular Research Institute, Emory University School of Medicine, Atlanta, Georgia
| | - Brett J Wong
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| |
Collapse
|
10
|
Wong BJ, Turner CG, Miller JT, Walker DC, Sebeh Y, Hayat MJ, Otis JS, Quyyumi AA. Sensory nerve-mediated and nitric oxide-dependent cutaneous vasodilation in normotensive and prehypertensive non-Hispanic blacks and whites. Am J Physiol Heart Circ Physiol 2020; 319:H271-H281. [PMID: 32559139 DOI: 10.1152/ajpheart.00177.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The purpose of this study was to investigate the effect of race and subclinical elevations in blood pressure (i.e., prehypertension) on cutaneous sensory nerve-mediated and nitric oxide (NO)-dependent vasodilation. We recruited participants who self-identified as either non-Hispanic black (n = 16) or non-Hispanic white (n = 16). Within each group, participants were subdivided as either normotensive (n = 8 per group) or prehypertensive (n = 8 per group). Each participant was instrumented with four intradermal microdialysis fibers: 1) control (lactated Ringer's), 2) 5% lidocaine (sensory nerve inhibition), 3) 20 mM Nω-nitro-l-arginine methyl ester (l-NAME) (NO synthase inhibition), and 4) lidocaine + l-NAME. Skin blood flow was assessed via laser-Doppler flowmetry, and each site underwent local heating from 33°C to 39°C. At the plateau, 20 mM l-NAME were infused at control and lidocaine sites to quantify NO-dependent vasodilation. Maximal vasodilation was induced via 54 mM sodium nitroprusside and local heating to 43°C. Data are means ± SD. Sensory nerve-mediated cutaneous vasodilation was reduced in prehypertensive non-Hispanic white (34 ± 7%) and both non-Hispanic black groups (normotensive, 20 ± 9%, prehypertensive, 24 ± 15%) relative to normotensive non-Hispanic whites (54 ± 12%). NO-dependent vasodilation was also reduced in prehypertensive non-Hispanic white (41 ± 7%) and both non-Hispanic black groups (normotensive, 44 ± 7%, prehypertensive, 19 ± 7%) relative to normotensive non-Hispanic whites (60 ± 11%). The decrease in NO-dependent vasodilation in prehypertensive non-Hispanic blacks was further reduced relative to all other groups. These data suggest subclinical increases in blood pressure adversely affect sensory-mediated and NO-dependent vasodilation in both non-Hispanic blacks and whites.NEW & NOTEWORTHY Overt hypertension is known to reduce cutaneous sensory nerve-mediated and nitric oxide (NO)-dependent vasodilation, but the effect of subclinical increases in blood pressure (i.e., prehypertension) is unknown. The combined effect of race and prehypertension is also unknown. In this study, we found that prehypertension reduces cutaneous sensory nerve-mediated and NO-dependent vasodilation in both non-Hispanic white and black populations, with the greatest reductions observed in prehypertensive non-Hispanic blacks.
Collapse
Affiliation(s)
- Brett J Wong
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Casey G Turner
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - James T Miller
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Demetria C Walker
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Yesser Sebeh
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Matthew J Hayat
- School of Public Health, Georgia State University, Atlanta, Georgia
| | - Jeffrey S Otis
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia
| | - Arshed A Quyyumi
- Emory Clinical Cardiovascular Research Institute, School of Medicine, Emory University, Atlanta, Georgia
| |
Collapse
|
11
|
Mallette MM, Cheung SS, Kumar RI, Hodges GJ, Holmes MWR, Gabriel DA. The effects of local forearm heating and cooling on motor unit properties during submaximal contractions. Exp Physiol 2020; 106:200-211. [DOI: 10.1113/ep088256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/07/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Matthew M. Mallette
- Department of Kinesiology and Physical Education Wilfrid Laurier University Waterloo Ontario Canada
- Department of Kinesiology Brock University St Catharines Ontario Canada
| | - Stephen S. Cheung
- Department of Kinesiology Brock University St Catharines Ontario Canada
| | - Robert I. Kumar
- Department of Kinesiology Brock University St Catharines Ontario Canada
| | - Gary J. Hodges
- Department of Kinesiology Brock University St Catharines Ontario Canada
| | | | - David A. Gabriel
- Department of Kinesiology Brock University St Catharines Ontario Canada
| |
Collapse
|
12
|
Lobov GI, Gerasimenko YP, Moshonkina TR. Mechanisms of Blood Flow Regulation in the Skin during Stimulation of the Spinal Cord in Humans. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2019; 485:27-29. [PMID: 31197588 DOI: 10.1134/s0012496619020030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/30/2018] [Accepted: 11/30/2018] [Indexed: 01/14/2023]
Abstract
Changes in the blood flow in the shin skin were observed by laser Doppler flowmetry after transcutaneous electrical spinal cord stimulation (TSCS) by subthreshold bipolar pulses with a frequency of 30 Hz in 12 healthy subjects. It was found that TSCS in the area of the T11 and L1 vertebrae led to a significant increase in skin blood flow. The microcirculation rate increased by more than 85% relative to the baseline at a stimulus intensity of 90% of the motor threshold. Cutaneous blood flow activization by TSCS is implemented mainly through the antidromic stimulation of sensory nerve fibers. Nitric oxide (NO) is an important mediator that contributes to vasodilation and increase in cutaneous blood flow upon TSCS. NO is predominantly of endothelial origin.
Collapse
Affiliation(s)
- G I Lobov
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034, St. Petersburg, Russia.
| | - Yu P Gerasimenko
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034, St. Petersburg, Russia
| | - T R Moshonkina
- Pavlov Institute of Physiology, Russian Academy of Sciences, 199034, St. Petersburg, Russia
| |
Collapse
|
13
|
Hodges GJ, Cheung SS. The effect of repeated bouts of hyperaemia on sensory nerve-mediated cutaneous vasodilatation in humans. Microvasc Res 2018; 119:22-28. [DOI: 10.1016/j.mvr.2018.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 10/17/2022]
|
14
|
Tan CH, McNaughton PA. TRPM2 and warmth sensation. Pflugers Arch 2018; 470:787-798. [PMID: 29552700 PMCID: PMC5942353 DOI: 10.1007/s00424-018-2139-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 03/08/2018] [Accepted: 03/09/2018] [Indexed: 01/08/2023]
Abstract
The abilities to detect warmth and heat are critical for the survival of all animals, both in order to be able to identify suitable thermal environments for the many different activities essential for life and to avoid damage caused by extremes of temperature. Several ion channels belonging to the TRP family are activated by non-noxious warmth or by heat and are therefore plausible candidates for thermal detectors, but identifying those that actually regulate warmth and heat detection in intact animals has proven problematic. TRPM2 has recently emerged as a likely candidate for the detector of non-noxious warmth, as it is expressed in sensory neurons, and mice show deficits in the detection of warmth when TRPM2 is genetically deleted. TRPM2 is a chanzyme, containing a thermally activated TRP ion channel domain attached to a C-terminal motif, derived from a mitochondrial ADP ribose pyrophosphatase, that confers on the channel sensitivity to ADP ribose and reactive oxygen species such as hydrogen peroxide. Several open questions remain. Male mammals prefer cooler environments than female, but the molecular basis of this sex difference is unknown. TRPM2 plays a role in regulating body temperature, but are other warmth-detecting mechanisms also involved? TRPM2 is expressed in autonomic neurons, but does it confer a sensory function in addition to the well-known motor functions of autonomic neurons? TRPM2 is thought to play important roles in the immune system, in pain and in insulin secretion, but the mechanisms are unclear. TRPM2 has to date received less attention than many other members of the TRP family but is rapidly assuming importance both in normal physiology and as a key target in disease pathology.
Collapse
Affiliation(s)
- Chun-Hsiang Tan
- Department of Neurology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Peter A McNaughton
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, Guy's Campus, King's College London, London, SE1 1UL, UK.
| |
Collapse
|
15
|
Hodges GJ, Mallette MM, Martin ZT, Del Pozzi AT. Effect of sympathetic nerve blockade on low-frequency oscillations of forearm and leg skin blood flow in healthy humans. Microcirculation 2017. [DOI: 10.1111/micc.12388] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Gary J. Hodges
- Environmental Ergonomics Laboratory; Brock University; St Catharines ON Canada
| | - Matthew M. Mallette
- Environmental Ergonomics Laboratory; Brock University; St Catharines ON Canada
| | - Zachary T. Martin
- Integrative Exercise Physiology Laboratory; Ball State University; Muncie IN USA
| | - Andrew T. Del Pozzi
- Integrative Exercise Physiology Laboratory; Ball State University; Muncie IN USA
| |
Collapse
|
16
|
Jonasson H, Bergstrand S, Nystrom FH, Länne T, Östgren CJ, Bjarnegård N, Fredriksson I, Larsson M, Strömberg T. Skin microvascular endothelial dysfunction is associated with type 2 diabetes independently of microalbuminuria and arterial stiffness. Diab Vasc Dis Res 2017; 14:363-371. [PMID: 28482676 DOI: 10.1177/1479164117707706] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Skin and kidney microvascular functions may be affected independently in diabetes mellitus. We investigated skin microcirculatory function in 79 subjects with diabetes type 2, where 41 had microalbuminuria and 38 not, and in 41 age-matched controls. The oxygen saturation, fraction of red blood cells and speed-resolved microcirculatory perfusion (% red blood cells × mm/s) divided into three speed regions: 0-1, 1-10 and above 10 mm/s, were assessed during baseline and after local heating of the foot with a new device integrating diffuse reflectance spectroscopy and laser Doppler flowmetry. Arterial stiffness was assessed as carotid-femoral pulse wave velocity. Subjects with diabetes and microalbuminuria had significantly higher carotid-femoral pulse wave velocity compared to subjects without microalbuminuria and to controls. The perfusion for speeds 0-1 mm/s and red blood cell tissue fraction were reduced in subjects with diabetes at baseline and after heating, independent of microalbuminuria. These parameters were correlated to HbA1c. In conclusion, the reduced nutritive perfusion and red blood cell tissue fraction in type 2 diabetes were related to long-term glucose control but independent of microvascular changes in the kidneys and large-vessel stiffness. This may be due to different pathogenic pathways in the development of nephropathy, large-vessel stiffness and cutaneous microvascular impairment.
Collapse
Affiliation(s)
- Hanna Jonasson
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Sara Bergstrand
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Fredrik H Nystrom
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Toste Länne
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Carl Johan Östgren
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Niclas Bjarnegård
- 2 Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | - Ingemar Fredriksson
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
- 3 Perimed AB, Stockholm, Sweden
| | - Marcus Larsson
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| | - Tomas Strömberg
- 1 Department of Biomedical Engineering, Linköping University, Linköping, Sweden
| |
Collapse
|
17
|
Hodges GJ, Martin ZT, Del Pozzi AT. Neuropeptide Y not involved in cutaneous vascular control in young human females taking oral contraceptive hormones. Microvasc Res 2017; 113:9-15. [PMID: 28427990 DOI: 10.1016/j.mvr.2017.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 04/11/2017] [Accepted: 04/15/2017] [Indexed: 11/27/2022]
Abstract
We previously reported that the cutaneous vasodilator response to local warming in males required noradrenaline (NA) and neuropeptide-Y (NPY). Animal work has shown no role for NPY in female vascular control. We investigated the contribution of NA and NPY in human female cutaneous vascular control. Nine female and nine male participants volunteered. To elucidate whether synthetic oestrogen and progesterone altered cutaneous vascular responses, females were tested in high-hormone (HH) and low-hormone (LH) phases of oral contraceptive pill (OCP). Skin blood flow was assessed by laser-Doppler flowmetry and expressed as cutaneous vascular conductance (CVC). Treatments were: control, combined yohimbine and propranolol (YP), BIBP-3226, and bretylium tosylate (BT). YP and BT increased basal CVC (p<0.05) relative to control sites in both HH and LH phases; though, BIBP-3226 had no effect in either phase (both p>0.05). Males basal CVC was increased at all treated sites compared to control sites (all p<0.05). YP and BT treated sites were higher in HH compared to LH (p<0.05). YP and BT treatment reduced the local warming-induced vasodilatation compared to control sites (p>0.05) in both HH and LH phases; whereas, BIBP-3226 treatment had no effect (p>0.05). In males, the vasodilatation achieved at all treated sites was reduced compared to the untreated control site (p<0.05). Data indicate that NA, not NPY, regulates basal skin blood flow and contributes to the vasodilator response to local warming in young females; however, both NA and NPY play a role in both basal and heat-induced cutaneous responses in males.
Collapse
Affiliation(s)
- Gary J Hodges
- Environmental Ergonomics Laboratory, Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada.
| | - Zachary T Martin
- Integrative Exercise Physiology Laboratory, School of Kinesiology, Ball State University, 2000 West University Avenue, Muncie, IN 47306, USA.
| | - Andrew T Del Pozzi
- Integrative Exercise Physiology Laboratory, School of Kinesiology, Ball State University, 2000 West University Avenue, Muncie, IN 47306, USA.
| |
Collapse
|
18
|
Sauvet F, Arnal PJ, Tardo-Dino PE, Drogou C, Van Beers P, Bougard C, Rabat A, Dispersyn G, Malgoyre A, Leger D, Gomez-Merino D, Chennaoui M. Protective effects of exercise training on endothelial dysfunction induced by total sleep deprivation in healthy subjects. Int J Cardiol 2017; 232:76-85. [DOI: 10.1016/j.ijcard.2017.01.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 11/30/2016] [Accepted: 01/04/2017] [Indexed: 12/31/2022]
|
19
|
Stoyneva Z, Velcheva I, Antonova N, Titianova E. Microvascular reactivity to thermal stimulation in patients with diabetes mellitus and polyneuropathy. Clin Hemorheol Microcirc 2017; 65:67-75. [DOI: 10.3233/ch-15107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Z. Stoyneva
- Department of Neurology, University Hospital St. Ivan Rilsky – Sofia, Medical Universities of Sofia and Plovdiv, Bulgaria
| | - I. Velcheva
- Department of Neurology, University Hospital of Neurology and Psychiatry, Medical University, Sofia, Bulgaria
| | - N. Antonova
- Department of Biomechanics, Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - E. Titianova
- Clinic of Functional Diagnostics of the Nervous System, Military Medical Academy, Sofia, Bulgaria
| |
Collapse
|
20
|
Hodges GJ, McGarr GW, Mallette MM, Del Pozzi AT, Cheung SS. The contribution of sensory nerves to the onset threshold for cutaneous vasodilatation during gradual local skin heating of the forearm and leg. Microvasc Res 2016; 105:1-6. [DOI: 10.1016/j.mvr.2015.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 11/03/2015] [Accepted: 12/08/2015] [Indexed: 10/22/2022]
|
21
|
Nieuwenhoff MD, Wu Y, Huygen FJPM, Schouten AC, van der Helm FCT, Niehof SP. Reproducibility of axon reflex-related vasodilation assessed by dynamic thermal imaging in healthy subjects. Microvasc Res 2016; 106:1-7. [PMID: 26956622 DOI: 10.1016/j.mvr.2016.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Small nerve fiber dysfunction is an early feature of diabetic neuropathy. There is a strong clinical need for a non-invasive method to assess small nerve fiber function. Small nerve fibers mediate axon reflex-related vasodilation and play an important role in thermoregulation. Assessing the reflex vasodilation after local heating might elucidate some aspects of small fiber functioning. In this study, we determined the reproducibility of the reflex vasodilation after short local heating in healthy subjects, assessed with thermal imaging and laser Doppler imaging. METHODS Healthy subjects underwent six heating rounds in one session (protocol I, N=10) or spread over two visits (protocol II, N=20). Reflex vasodilation was elicited by heating the skin to 42°C with an infrared lamp. Skin temperature and skin blood flow were recorded during heating and recovery with a thermal imaging camera and a laser Doppler imager. Skin temperature curves were fitted with a mathematical model to describe the heating and recovery phase with time constant tau (tauHeat and tauCool1). RESULTS The reproducibility of tau within a session was moderate to excellent (intra-class correlation coefficient 0.42-0.86) and good (0.71-0.72) between different sessions. Within one session the differences in tauHeat were small (bias±SD -1.3±18.9s); the bias between two visits was -1.2±12.2s. For tauCool1 the differences were also small, 1.4±6.6s within a session and between visits -1.4±11.6s. CONCLUSIONS The heat induced axon reflex-related vasodilation, assessed with thermal imaging and laser Doppler imaging, was reproducible both within a session and between different sessions. Tau describes the temporal profile in one parameter and represents the effects of all changes including blood flow and as such, is an indicator of the vasodilator function. TauHeat and tauCool1 can accurately describe the dynamics of the axon reflex-related vasodilator response in the heating and recovery phase respectively.
Collapse
Affiliation(s)
- M D Nieuwenhoff
- Department of Anesthesiology and Pain Medicine, Erasmus MC University Medical Center, Room Ba-430, P.O. box 2040, 3000CA Rotterdam, The Netherlands.
| | - Y Wu
- Department of Biomechanical Engineering, Delft University of Technology, Mekelweg 2, 2628CD Delft, The Netherlands.
| | - F J P M Huygen
- Department of Anesthesiology and Pain Medicine, Erasmus MC University Medical Center, Room Ba-430, P.O. box 2040, 3000CA Rotterdam, The Netherlands.
| | - A C Schouten
- Department of Biomechanical Engineering, Delft University of Technology, Mekelweg 2, 2628CD Delft, The Netherlands; Department of Biomechanical Engineering, MIRA Institute, University of Twente, Building Zuidhorst, P.O. box 217, 7500AE Enschede, The Netherlands.
| | - F C T van der Helm
- Department of Biomechanical Engineering, Delft University of Technology, Mekelweg 2, 2628CD Delft, The Netherlands.
| | - S P Niehof
- Department of Anesthesiology and Pain Medicine, Erasmus MC University Medical Center, Room Ba-430, P.O. box 2040, 3000CA Rotterdam, The Netherlands.
| |
Collapse
|
22
|
Del Pozzi AT, Miller JT, Hodges GJ. The effect of heating rate on the cutaneous vasomotion responses of forearm and leg skin in humans. Microvasc Res 2016; 105:77-84. [PMID: 26808211 DOI: 10.1016/j.mvr.2016.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022]
Abstract
We examined skin blood flow (SkBF) and vasomotion in the forearm and leg using laser-Doppler fluxmetry (LDF) and spectral analysis to investigate endothelial, sympathetic, and myogenic activities in response to slow (0.1 °C·10 s(-1)) and fast (0.5 °C·10 s(-1)) local heating. At 33 °C (thermoneutral) endothelial activity was higher in the legs than the forearms (P ≤ 0.02). Fast-heating increased SkBF more than slow heating (P=0.037 forearm; P=0.002 leg). At onset of 42 °C, endothelial (P=0.043 forearm; P=0.48 leg) activity increased in both regions during the fast-heating protocol. Following prolonged heating (42 °C) endothelial activity was higher in both the forearm (P=0.002) and leg (P<0.001) following fast-heating. These results confirm regional differences in the response to local heating and suggest that the greater increase in SkBF in response to fast local heating is initially due to increased endothelial and sympathetic activity. Furthermore, with sustained local skin heating, greater vasodilatation was observed with fast heating compared to slow heating. These data indicate that this difference is due to greater endothelial activity following fast heating compared to slow heating, suggesting that the rate of skin heating may alter the mechanisms contributing to cutaneous vasodilatation.
Collapse
Affiliation(s)
- Andrew T Del Pozzi
- Integrative Exercise Physiology Laboratory, School of Kinesiology, Ball State University, Muncie, IN 47306, United States
| | - James T Miller
- Exercise Physiology Laboratory, Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, United States
| | - Gary J Hodges
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.
| |
Collapse
|
23
|
Smith CJ, Johnson JM. Responses to hyperthermia. Optimizing heat dissipation by convection and evaporation: Neural control of skin blood flow and sweating in humans. Auton Neurosci 2016; 196:25-36. [PMID: 26830064 DOI: 10.1016/j.autneu.2016.01.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 01/05/2023]
Abstract
Under normothermic, resting conditions, humans dissipate heat from the body at a rate approximately equal to heat production. Small discrepancies between heat production and heat elimination would, over time, lead to significant changes in heat storage and body temperature. When heat production or environmental temperature is high the challenge of maintaining heat balance is much greater. This matching of heat elimination with heat production is a function of the skin circulation facilitating heat transport to the body surface and sweating, enabling evaporative heat loss. These processes are manifestations of the autonomic control of cutaneous vasomotor and sudomotor functions and form the basis of this review. We focus on these systems in the responses to hyperthermia. In particular, the cutaneous vascular responses to heat stress and the current understanding of the neurovascular mechanisms involved. The available research regarding cutaneous active vasodilation and vasoconstriction is highlighted, with emphasis on active vasodilation as a major responder to heat stress. Involvement of the vasoconstrictor and active vasodilator controls of the skin circulation in the context of heat stress and nonthermoregulatory reflexes (blood pressure, exercise) are also considered. Autonomic involvement in the cutaneous vascular responses to direct heating and cooling of the skin are also discussed. We examine the autonomic control of sweating, including cholinergic and noncholinergic mechanisms, the local control of sweating, thermoregulatory and nonthermoregulatory reflex control and the possible relationship between sudomotor and cutaneous vasodilator function. Finally, we comment on the clinical relevance of these control schemes in conditions of autonomic dysfunction.
Collapse
Affiliation(s)
- Caroline J Smith
- Department of Health and Exercise Science, Appalachian State University, Boone, NC 28608-2071, United States
| | - John M Johnson
- Department of Physiology, University of Texas Health Science Center, San Antonio, TX 78229-3901, United States
| |
Collapse
|
24
|
Harvey JC, Roseguini BT, Goerger BM, Fallon EA, Wong BJ. Acute Thermotherapy Prevents Impairments in Cutaneous Microvascular Function Induced by a High Fat Meal. J Diabetes Res 2016; 2016:1902325. [PMID: 27595112 PMCID: PMC4993934 DOI: 10.1155/2016/1902325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/09/2016] [Accepted: 07/05/2016] [Indexed: 12/20/2022] Open
Abstract
We tested the hypothesis that a high fat meal (HFM) would impair cutaneous vasodilation, while thermotherapy (TT) would reverse the detrimental effects. Eight participants were instrumented with skin heaters and laser-Doppler (LD) probes and tested in three trials: control, HFM, and HFM + TT. Participants wore a water-perfused suit perfused with 33°C (control and HFM) or 50°C (HFM + TT) water. Participants consumed 1 g fat/kg body weight. Blood samples were taken at baseline and two hours post-HFM. Blood pressure was measured every 5-10 minutes. Microvascular function was assessed via skin local heating from 33°C to 39°C two hours after HFM. Cutaneous vascular conductance (CVC) was calculated and normalized to maximal vasodilation (%CVCmax). HFM had no effect on initial peak (48 ± 4 %CVCmax) compared to control (49 ± 4 %CVCmax) but attenuated the plateau (51 ± 4 %CVCmax) compared to control (63 ± 4 %CVCmax, P < 0.001). Initial peak was augmented in HFM + TT (66 ± 4 %CVCmax) compared to control and HFM (P < 0.05), while plateau (73 ± 3 % CVCmax) was augmented only compared to the HFM trial (P < 0.001). These data suggest that HFM negatively affects cutaneous vasodilation but can be minimized by TT.
Collapse
Affiliation(s)
- Jennifer C. Harvey
- Department of Kinesiology & Health, Georgia State University, Atlanta, GA 30302-3975, USA
| | - Bruno T. Roseguini
- Department of Health & Kinesiology, Purdue University, West Lafayette, IN 47907, USA
| | - Benjamin M. Goerger
- Department of Kinesiology & Health, Georgia State University, Atlanta, GA 30302-3975, USA
| | - Elizabeth A. Fallon
- Department of Kinesiology & Health, Georgia State University, Atlanta, GA 30302-3975, USA
| | - Brett J. Wong
- Department of Kinesiology & Health, Georgia State University, Atlanta, GA 30302-3975, USA
- *Brett J. Wong:
| |
Collapse
|
25
|
The contribution of sensory nerves to cutaneous vasodilatation of the forearm and leg to local skin heating. Eur J Appl Physiol 2015; 115:2091-8. [PMID: 25998144 DOI: 10.1007/s00421-015-3188-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 05/09/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE The initial cutaneous vasodilatory response to local skin heating is larger in the forearm than the leg. While the initial vasodilatation of the forearm to local heating is primarily dependent on sensory nerves, their role in the leg is unknown. We compared the contribution of sensory nerves in driving the cutaneous vasodilatory response of the forearm and leg to local heating using local anaesthetic (EMLA) cream. METHOD In seven participants, two skin sites were selected on both the dorsal forearm and anterolateral calf; one site on each region received EMLA, with the other an untreated control. All sites were controlled at 33 °C and then locally heated to 42 °C with integrated laser-Doppler local heating probes. RESULTS Cutaneous vascular conductance (CVC) during the initial vasodilatation to local heating was smaller in the leg (47 ± 9% max) compared to the forearm (62 ± 7 % max) (P = 0.012). EMLA reduced the initial vasodilatation at both the leg (27 ± 13 % max) (P = 0.02) and forearm (33 ± 14% max) (P < 0.001). The times to onset of vasodilatation, initial vasodilatory peak, and plateau phase were longer in the leg compared to the forearm (all P < 0.05), and EMLA increased these times in both regions (both P < 0.05). CVC during the plateau phase to sustained local skin heating was higher in the leg compared to the forearm at both the untreated (93 ± 6 vs. 85 ± 4% max) (P = 0.33) and EMLA-treated (94 ± 5 vs. 86 ± 6% max) (P = 0.001) sites; EMLA did not affect CVC (P > 0.05). CONCLUSION The differences in the initial vasodilatory peak to local skin heating between the forearm and the leg are due to the contribution of sensory nerves.
Collapse
|
26
|
Del Pozzi AT, Hodges GJ. Comparison of the noradrenergic sympathetic nerve contribution during local skin heating at forearm and leg sites in humans. Eur J Appl Physiol 2015; 115:1155-64. [DOI: 10.1007/s00421-014-3097-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 12/24/2014] [Indexed: 01/08/2023]
|
27
|
Del Pozzi AT, Hodges GJ. To reheat, or to not reheat: that is the question: The efficacy of a local reheating protocol on mechanisms of cutaneous vasodilatation. Microvasc Res 2015; 97:47-54. [DOI: 10.1016/j.mvr.2014.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/08/2014] [Accepted: 09/25/2014] [Indexed: 10/24/2022]
|
28
|
Noninvasive examination of endothelial, sympathetic, and myogenic contributions to regional differences in the human cutaneous microcirculation. Microvasc Res 2014; 93:87-91. [DOI: 10.1016/j.mvr.2014.04.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/25/2014] [Accepted: 04/08/2014] [Indexed: 11/21/2022]
|
29
|
Bruning RS, Kenney WL, Alexander LM. Altered skin flowmotion in hypertensive humans. Microvasc Res 2014; 97:81-7. [PMID: 24418051 DOI: 10.1016/j.mvr.2014.01.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Revised: 12/11/2013] [Accepted: 01/01/2014] [Indexed: 01/10/2023]
Abstract
Essential hypertensive humans exhibit attenuated cutaneous nitric oxide (NO)-dependent vasodilation. Using spectral analysis (fast Fourier transformation) we aimed to characterize the skin flowmotion contained in the laser-Doppler flowmetry recordings during local heating-induced vasodilation before and after concurrent pharmacological inhibition of nitric oxide synthase (NOS) in hypertensive and age-matched normotensive men and women. We hypothesized that hypertensive subjects would have lower total power spectral densities (PSDs), specifically in the frequency intervals associated with intrinsic endothelial and neurogenic control of the microvasculature. Furthermore, we hypothesized that NOS inhibition would attenuate the endothelial frequency interval. Laser-Doppler flowmetry recordings during local heating experiments from 18 hypertensive (MAP: 108±2mmHg) and 18 normotensive (MAP: 88±2mmHg) men and women were analyzed. Within site NO-dependent vasodilation was assessed by perfusion of a non-specific NOS inhibitor (N(G)-nitro-l-arginine methyl ester; l-NAME) through intradermal microdialysis during the heating-induced plateau in skin blood flow. Local heating-induced vasodilation increased total PSD for all frequency intervals (all p<0.001). Hypertensives had a lower total PSD (p=0.03) and absolute neurogenic frequency intervals (p<0.01) compared to the normotensives. When normalized as a percentage of total PSD, hypertensives had reduced neurogenic (p<0.001) and augmented myogenic contributions (p=0.04) to the total spectrum. NOS inhibition decreased total PSD (p<0.001) for both groups, but hypertensives exhibited lower absolute endothelial (p<0.01), neurogenic (p<0.05), and total PSD (p<0.001) frequency intervals compared to normotensives. These data suggest that essential hypertension results in altered neurogenic and NOS-dependent control of skin flowmotion and support the use of spectral analysis as a non-invasive technique to study vasoreactivity.
Collapse
Affiliation(s)
- R S Bruning
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802-6900, USA
| | - W L Kenney
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802-6900, USA
| | - L M Alexander
- Department of Kinesiology, The Pennsylvania State University, University Park, PA 16802-6900, USA.
| |
Collapse
|
30
|
Hodges GJ, Sparks PA. Noradrenaline and neuropeptide Y contribute to initial, but not sustained, vasodilatation in response to local skin warming in humans. Exp Physiol 2013; 99:381-92. [PMID: 24213859 DOI: 10.1113/expphysiol.2013.075549] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
NEW FINDINGS What is the central question of this study? Previous work has produced the counterintuitive finding that the vasoconstrictor neurotransmitters noradrenaline and neuropeptide Y are involved in vasodilatation. We aimed to discover whether sympathetic neurotransmitters are required for the sustained vasodilatation in response to local skin warming, as has been previously suggested, and to determine whether noradrenaline and neuropeptide Y are 'mediating' the sustained vasodilator response directly or acting to 'prime' (or kick-start) it. What is the main finding and its importance? We have found that noradrenaline and neuropeptide Y are required at the initiation of vasodilatation in response to local skin warming, if a complete vasodilator response is to be achieved; however, they are not required once vasodilatation has begun. In a three-part study, we examined whether noradrenaline, neuropeptide Y (NPY) and endothelial nitric oxide synthase (eNOS) were involved in the sustained vasodilatation in response to local skin warming. Forearm skin sites were instrumented with intradermal microdialysis fibres, local skin heaters and laser-Doppler flow probes. Local skin temperature (T(loc)) was increased from 34 to 42°C at a rate of 0.5°C (10 s)(-1). Laser-Doppler flow was expressed as cutaneous vascular conductance (CVC; laser-Doppler flow/mean arterial pressure). In part 1, three skin sites were prepared; two were treated with the study vehicle (lactated Ringer solution), while the third site was treated with yohimbine and propranolol to antagonize α- and β-receptors, and 10 min of baseline data were record at a T(loc) of 34°C. Receptor antagonism was confirmed via infusion of clonidine. The T(loc) was increased to 42°C at all sites. Once CVC had stabilized, site 2 was treated with yohimbine and propranolol to examine the effect of adrenergic receptor blockade on sustained vasodilatation of the skin. Receptor antagonism was again confirmed via infusion of clonidine. All sites were treated with sodium nitroprusside, and T(loc) was increased to 43°C to elicit maximal vasodilatation. In parts 2 and 3, the general protocol was the same, except that BIBP-3226 was used to antagonize Y(1)-receptors, NPY to test the efficacy of the antagonism, N(G)-amino-l-arginine to inhibit eNOS and ACh to test the adequacy of inhibition. Compared with control conditions, antagonism of α- and β-receptors, Y(1)-receptors and eNOS before local skin warming reduced the initial and sustained vasodilatation in response to increased T(loc). However, treatment with yohimbine and propranolol or BIBP-3226 after local skin warming did not affect the sustained vasodilatation [CVC, 90 ± 3 versus 89 ± 3%max (control vs. yohimbine and propranolol) and 88 ± 5 versus 87 ± 4%max (control vs. BIBP-3226); P > 0.05]. N(G)-Amino-l-arginine perfusion caused a large reduction in CVC during this phase (89 ± 5 versus 35 ± 4%max; P < 0.05). These data indicate that if their actions are antagonized after local warming and cutaneous vasodilatation has occurred, noradrenaline and NPY play little, if any, role in the sustained vasodilatation in response to local skin warming. However, eNOS contributes markedly to the sustained vasodilatation regardless of when it is inhibited.
Collapse
Affiliation(s)
- Gary J Hodges
- * Department of Kinesiology, 2007 Moore Hall, The University of Alabama, Tuscaloosa, AL 35487, USA.
| | | |
Collapse
|
31
|
Del Pozzi AT, Carter SJ, Collins AB, Hodges GJ. The regional differences in the contribution of nitric oxide synthase to skin blood flow at forearm and lower leg sites in response to local skin warming. Microvasc Res 2013. [DOI: 10.1016/j.mvr.2013.10.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
32
|
Hodges GJ, Sparks PA. Contributions of endothelial nitric oxide synthase, noradrenaline, and neuropeptide Y to local warming-induced cutaneous vasodilatation in men. Microvasc Res 2013; 90:128-34. [PMID: 24012636 DOI: 10.1016/j.mvr.2013.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 07/24/2013] [Accepted: 08/28/2013] [Indexed: 12/31/2022]
Abstract
We performed a two-part study to determine the roles of endothelial nitric oxide synthase (eNOS) and the vasoconstrictor nerves neurotransmitters noradrenaline (NA) and neuropeptide Y (NPY) in the cutaneous vasodilator response to local skin warming. Forearm skin sites were instrumented with intradermal microdialysis fibres, local heaters, and laser-Doppler flow (LDF) probes. Sites were locally heated from 34 to 42°C. LDF was expressed as cutaneous vascular conductance (CVC; LDF/mean arterial pressure). In Part I, we tested whether sympathetic noradrenergic nerves acted via eNOS. In 8 male participants, treatments were as follows: 1) untreated; 2) bretylium tosylate (BT), preventing sympathetic neurotransmitter release; 3) l-NAA to inhibit eNOS; and 4) combined BT+l-NAA. At treated sites, the initial peak response was markedly reduced, and the plateau phase response to 35min of local warming was also reduced (P<0.05), which was not different among those sites (P>0.05). In Part II, we tested whether NA and NPY were involved in the vasodilator response to local warming. In Part IIa, treatments were: 1) untreated; 2) propranolol and yohimbine to antagonize α- and β-receptors; 3) l-NAA; and 4) combined propranolol, yohimbine, and l-NAA. In Part IIb, conditions were: 1) untreated; 2) BIBP to antagonize Y1-receptors; 3) l-NAA; and 4) combined BIBP and l-NAA. All treatments caused a reduction in the initial peak and plateau responses to local skin warming (P<0.05). The results of Part II indicate that both NA and NPY play roles in the cutaneous vasodilator response and their actions are achieved via eNOS. These data indicate that NA and NPY are involved in the initial, rapid rise in skin blood flow at the onset of local skin warming. However, their vasodilator actions in response to local skin warming appears to be manifested through eNOS.
Collapse
Affiliation(s)
- Gary J Hodges
- Exercise Physiology Laboratory, Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, USA.
| | | |
Collapse
|
33
|
Metzler-Wilson K, Wilson TE. Topical anaesthesia does not affect cutaneous vasomotor or sudomotor responses in human skin. ACTA ACUST UNITED AC 2013; 33:25-33. [PMID: 23663206 DOI: 10.1111/aap.12007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 02/16/2013] [Accepted: 03/08/2013] [Indexed: 12/31/2022]
Abstract
(1) The effects of local sensory blockade (topical anaesthesia) on eccrine sweat glands and cutaneous circulation are not well understood. This study aimed to determine whether topical lidocaine/prilocaine alters eccrine sweat gland and cutaneous blood vessel responses. (2) Sweating (capacitance hygrometry) was induced via forearm intradermal microdialysis of five acetylcholine (ACh) doses (1 × 10(-4) to 1 × 10(0) m, 10-fold increments) in control and treated forearm sites in six healthy subjects. Nitric oxide-mediated vasodilatory (sodium nitroprusside) and adrenergic vasoconstrictor (noradrenaline) agonists were iontophoresed in lidocaine/prilocaine-treated and control forearm skin in nine healthy subjects during blood flow assessment (laser Doppler flowmetry, expressed as% from baseline cutaneous vascular conductance; CVC; flux/mean arterial pressure). (3) Non-linear regression curve fitting identified no change in the ED50 of ACh-induced sweating after sensory blockade (-1.42 ± 0.23 logM) compared to control (-1.27 ± 0.23 logM; P > .05) or in Emax (0.43 ± 0.08 with, 0.53 ± 0.16 mg cm(-2) min(-1) without lidocaine/prilocaine; P > .05). Sensory blockade did not alter the vasodilator response to sodium nitroprusside (1280 ± 548% change from baseline CVC with, 1204 ± 247% without lidocaine/prilocaine) or vasoconstrictor response to noradrenaline (-14 ± 4% change from baseline CVC with, -22 ± 14% without lidocaine/prilocaine; P > 0.05). (4) Cutaneous sensory blockade does not appear to alter nitric oxide-mediated vasodilation, adrenergic vasoconstriction, or cholinergic eccrine sweating dose-response sensitivity or responsiveness to maximal dose. Thus, lidocaine/prilocaine treatment should not affect sweat gland function or have blood flow implications for subsequent research protocols or clinical procedures.
Collapse
Affiliation(s)
- K Metzler-Wilson
- Ohio Musculoskeletal and Neurological Institute, Irvine Hall, Ohio University, Athens, OH, 45701, USA; Department of Physical Therapy, Lebanon Valley College, 101 N College Ave, Annville, PA, 17003, USA
| | | |
Collapse
|
34
|
Huang CS, Wang SF, Tsai YF. Axon reflex-related hyperemia induced by short local heating is reproducible. Microvasc Res 2012; 84:351-5. [PMID: 22796314 DOI: 10.1016/j.mvr.2012.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/31/2012] [Accepted: 07/05/2012] [Indexed: 01/15/2023]
Abstract
OBJECTIVES The axon reflex (AR) flare is induced by antidromic activation of afferent C-fibers during nociceptive stimulation. This response has been suggested to be modulated by sympathetic activity and basal level of nitric oxide. In previously used protocols of local thermal hyperemia (LTH), AR flare has been used in combination with maximal vasodilatation to study the integrated endothelial function. The aim of this study was to investigate the intra-session reproducibility of short heating-induced AR flare, the specific neural-mediated portion of LTH, and to compare the reproducibility between different forms of data expression. METHODS Short-heating LTH was assessed using single-point laser Doppler flowmetry (LDF) on bilateral volar surface of the forearm in 10 men and 10 women. The blood flux measurement included a non-heating process for 5 min, followed by a quick heating process from 33°C to 42°C for 5 min. The test was repeated 45 min later at the same recording sites with fixed holders. Baseline and heating blood flux were recorded and expressed as different forms of data. Reproducibility was assessed using coefficient of variation (CV) and intra-class correlation coefficient (ICC) statistics. RESULTS The reproducibility of peak cutaneous vascular conductance (CVC) (CV=16.02-17.31%, ICC=0.77-0.78), peak CVC change (CV=14.30-18.12%, ICC=0.80-0.86), and the 4 min area-under-the-curve (CV=18.37-18.70%, ICC=0.60-0.78) was acceptable. The time to peak flux of each recording site ranged from 90 to 209 s and all the peak fluxes have been achieved before 4 min of heating. CONCLUSIONS Single-point LDF is a reproducible technique of assessing AR flare on volar surface of the forearm when the heating period is reduced to 5 min and the recording sites are fixed. Using this new protocol, short-heating LTH has a potential to be used to evaluate the effects of acute physical or chemical interventions between two short-heating LTH tests to further explore the pathophysiological meaning of heating-induced AR flare.
Collapse
Affiliation(s)
- Chung-Shin Huang
- Department of Physiology, College of Medicine, National Taiwan University, No. 1 Jen-Ai Road, Section 1, Taipei 100, Taiwan, ROC.
| | | | | |
Collapse
|