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Kim KT, Gemechu DT, Seo E, Lee T, Park JW, Youn I, Kang JW, Lee SJ. Venous congestion affects neuromuscular changes in pigs in terms of muscle electrical activity and muscle stiffness. PLoS One 2023; 18:e0289266. [PMID: 37535620 PMCID: PMC10399817 DOI: 10.1371/journal.pone.0289266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/16/2023] [Indexed: 08/05/2023] Open
Abstract
Early detection of venous congestion (VC)-related diseases such as deep vein thrombosis (DVT) is important to prevent irreversible or serious pathological conditions. However, the current way of diagnosing DVT is only possible after recognizing advanced DVT symptoms such as swelling, pain, and tightness in affected extremities, which may be due to the lack of information on neuromechanical changes following VC. Thus, the goal of this study was to investigate acute neuromechanical changes in muscle electrical activity and muscle stiffness when VC was induced. The eight pigs were selected and the change of muscle stiffness from the acceleration and muscle activity in terms of integral electromyography (IEMG) was investigated in three VC stages. Consequently, we discovered a significant increase in the change in muscle stiffness and IEMG from the baseline to the VC stages (p < 0.05). Our results and approach can enable early detection of pathological conditions associated with VC, which can be a basis for further developing early diagnostic tools for detecting VC-related diseases.
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Affiliation(s)
- Keun-Tae Kim
- Korea Institute of Science and Technology, Bionics Research Center, Seoul, Korea Repub
| | - Duguma T. Gemechu
- Korea Institute of Science and Technology, Bionics Research Center, Seoul, Korea Repub
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul, Korea Repub
| | - Eunyoung Seo
- Korea Institute of Science and Technology, Bionics Research Center, Seoul, Korea Repub
| | - Taehoon Lee
- Korea Institute of Science and Technology, Bionics Research Center, Seoul, Korea Repub
| | - Jong Woong Park
- Department of Orthopaedic Surgery, Korea University Ansan Hospital, Ansan, Korea Repub
| | - Inchan Youn
- Korea Institute of Science and Technology, Bionics Research Center, Seoul, Korea Repub
| | - Jong Woo Kang
- Department of Orthopaedic Surgery, Korea University Anam Hospital, Seoul, Korea Repub
| | - Song Joo Lee
- Korea Institute of Science and Technology, Bionics Research Center, Seoul, Korea Repub
- Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology, Seoul, Korea Repub
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Claffey P, Pérez-Denia L, Lavan A, Kenny RA, Finucane C, Briggs R. Asymptomatic orthostatic hypotension and risk of falls in community-dwelling older people. Age Ageing 2022; 51:6936398. [PMID: 36571778 DOI: 10.1093/ageing/afac295] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Indexed: 12/27/2022] Open
Abstract
INTRODUCTION Many older people with orthostatic hypotension (OH) may not report typical symptoms of dizziness, light-headedness or unsteadiness. However, the relationships between OH and falls in the absence of typical symptoms are not yet established. METHODS Continuous orthostatic blood pressure (BP) was measured during active stand using a Finometer at Wave 1 of The Irish Longitudinal Study on Ageing in participants aged ≥ 70 years.OH, with and without dizziness, was defined as a sustained drop in systolic BP ≥ 20 and/or diastolic BP ≥ 10 mm Hg at 30, 60 and 90 seconds post-standing.The association between symptoms of dizziness and orthostatic BP was assessed with multi-level mixed-effects linear regression; logistic regression models assessed the longitudinal relationship between OH and falls at 6-year follow-up (Waves 2-5). RESULTS Almost 11% (n = 934, mean age 75 years, 51% female) had OH, two-thirds of whom were asymptomatic.Dizziness was not associated with systolic BP drop at 30 (β = 1.54 (-1.27, 4.36); p = 0.256), 60 (β = 2.64 (-0.19, 5.47); p = 0.476) or 90 seconds (β = 2.02 (-0.91, 4.95); p = 0.176) after standing in adjusted models.Asymptomatic OH was independently associated with unexplained falls (odds ratio 2.01 [1.11, 3.65]; p = 0.022) but not explained falls (OR 0.93 [0.53, 1.62]; p = 0.797) during follow-up. CONCLUSIONS Two-thirds of older people with OH did not report typical symptoms of light-headedness. Dizziness or unsteadiness after standing did not correlate with the degree of orthostatic BP drop or recovery. Participants with asymptomatic OH had a significantly higher risk of unexplained falls during follow-up, and this has important clinical implications for the assessment of older people with falls.
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Affiliation(s)
- Paul Claffey
- The Irish Longitudinal Study on Ageing, Trinity College Dublin, Dublin, Ireland.,Mercer's Institute for Successful Ageing, St James's Hospital, Dublin, Ireland.,Discipline of Medical Gerontology, Trinity College Dublin, Dublin, Ireland
| | - Laura Pérez-Denia
- Mercer's Institute for Successful Ageing, St James's Hospital, Dublin, Ireland.,Discipline of Medical Gerontology, Trinity College Dublin, Dublin, Ireland.,Department of Medical Physics and Bioengineering, St James's Hospital, Dublin, Ireland
| | - Amanda Lavan
- The Irish Longitudinal Study on Ageing, Trinity College Dublin, Dublin, Ireland.,Mercer's Institute for Successful Ageing, St James's Hospital, Dublin, Ireland.,Discipline of Medical Gerontology, Trinity College Dublin, Dublin, Ireland
| | - Rose Anne Kenny
- The Irish Longitudinal Study on Ageing, Trinity College Dublin, Dublin, Ireland.,Mercer's Institute for Successful Ageing, St James's Hospital, Dublin, Ireland.,Discipline of Medical Gerontology, Trinity College Dublin, Dublin, Ireland
| | - Ciarán Finucane
- Mercer's Institute for Successful Ageing, St James's Hospital, Dublin, Ireland.,Discipline of Medical Gerontology, Trinity College Dublin, Dublin, Ireland.,Department of Medical Physics and Bioengineering, St James's Hospital, Dublin, Ireland
| | - Robert Briggs
- The Irish Longitudinal Study on Ageing, Trinity College Dublin, Dublin, Ireland.,Mercer's Institute for Successful Ageing, St James's Hospital, Dublin, Ireland.,Discipline of Medical Gerontology, Trinity College Dublin, Dublin, Ireland
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Oue A, Iimura Y, Shinagawa A, Miyakoshi Y, Ota M. Acute dietary nitrate supplementation does not change venous volume and compliance in healthy young adults. Am J Physiol Regul Integr Comp Physiol 2022; 323:R331-R339. [PMID: 35816716 DOI: 10.1152/ajpregu.00083.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this randomized single-blind, placebo-controlled, crossover study, we investigated the influence of inorganic nitrate (NO3-) supplementation on venous volume and compliance in the resting forearm and calf. Twenty healthy young adults were assigned to receive an NO3--rich beverage (beetroot juice [BRJ]: 140 mL; ~8 mmol NO3-) or an NO3¯-depleted control beverage (prune juice [CON]: 166 mL; < 0.01 mmol NO3-). Two hours after consuming the allocated beverage, each participant rested in the supine position for 20 min. Cuffs were then placed around the right upper arm and right thigh, inflated to 60 mmHg for 8 min, and then decreased to 0 mmHg at a rate of 1 mmHg/s. During inflation and deflation of cuff pressure, changes in venous volume in the forearm and calf were measured by venous occlusion plethysmography. Venous compliance was calculated as the numerical derivative of the cuff pressure‒venous volume curve in the limbs. The plasma NO3- concentration was elevated by intake of BRJ (before, 15.5 ± 5.8 µM; after, 572.0 ± 116.1 µM, P < 0.05) but not by CON (before, 14.8 ± 7.2 µM; after, 15.3 ± 7.4 µM, P > 0.05). On the other hand, there was no significant difference in venous volume or compliance in the forearm or calf between BRJ and CON. These findings suggest that although acute inorganic NO3- supplementation may enhance the activity of nitric oxide (NO) via NO3- → nitrite → NO pathway, it does not influence venous volume or compliance in the limbs in healthy young adults.
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Affiliation(s)
- Anna Oue
- Faculty of Food and Nutritional Sciences, Toyo University, Gunma, Japan
| | - Yasuhiro Iimura
- Graduate School of Food and Nutritional Sciences, Toyo University, Gunma, Japan
| | - Akiho Shinagawa
- Graduate School of Food and Nutritional Sciences, Toyo University, Gunma, Japan
| | - Yuichi Miyakoshi
- Faculty of Food and Nutritional Sciences, Toyo University, Gunma, Japan
| | - Masako Ota
- Faculty of Food and Nutritional Sciences, Toyo University, Gunma, Japan
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4
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Hamaoka T, Leuenberger UA, Blaha C, Luck JC, Sinoway LI, Cui J. Baroreflex responses to limb venous distension in humans. Am J Physiol Regul Integr Comp Physiol 2022; 323:R267-R276. [PMID: 35726869 PMCID: PMC9359652 DOI: 10.1152/ajpregu.00028.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The venous distension reflex (VDR) is a pressor response evoked by peripheral venous distension and accompanied by increased muscle sympathetic nerve activity (MSNA). The effects of venous distension on the baroreflex, an important modulator of blood pressure (BP), has not been examined. The purpose of this study was to examine the effect of the VDR on baroreflex sensitivity (BRS). We hypothesized that the VDR will increase the sympathetic BRS (SBRS). Beat-by-beat heart rate (HR), BP and MSNA were recorded in 16 female and 19 male young healthy subjects. To induce venous distension, normal saline equivalent to 5% of the forearm volume was infused into the veins of the occluded forearm. SBRS was assessed from the relationship between diastolic BP and MSNA during spontaneous BP variations. Cardiovagal BRS (CBRS) was assessed with the sequence technique. Venous distension evoked significant increases in BP and MSNA. Compared to baseline, during the maximal VDR response period, SBRS was significantly increased (-3.1 ± 1.5 to -4.5 ± 1.6 bursts・100 heartbeat-1・mmHg-1, P < 0.01) and CBRS was significantly decreased (16.6 ± 5.4 to 13.8 ± 6.1 ms・mmHg-1, P < 0.01). No sex differences were observed in the effect of the VDR on SBRS or CBRS. These results indicate that in addition to its pressor effect, the VDR altered both SBRS and CBRS. We speculate that these changes in baroreflex function contribute to the modulation of MSNA and BP during limb venous distension.
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Affiliation(s)
- Takuto Hamaoka
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Urs A Leuenberger
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Cheryl Blaha
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Jonathan Carter Luck
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Lawrence I Sinoway
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Jian Cui
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
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ISHIKAWA M, MIURA H, TAMURA Y, MURAKAMI A. Effect of Electrical Muscle Stimulation on Vascular Endothelial Function during Prolonged Sitting. Phys Ther Res 2022; 25:127-133. [PMID: 36819917 PMCID: PMC9910348 DOI: 10.1298/ptr.e10191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 09/07/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE While prolonged sedentary behaviors (SBs) increase cardiovascular disease (CVD) risk, interrupting prolonged sitting (PS) with frequent light exercise reduces arterial functional decline. Skeletal muscle electrical stimulation (EMS) enhances peripheral circulation through passive muscle contraction, suggesting that EMS reduces CVD risk by providing an alternative to active exercise for prolonged SBs. This study aimed to investigate the effects of EMS to skeletal muscles during PS on the endothelial function of the brachial artery (BA). METHODS Study participants included 12 healthy adult men who were subjected to 15 min of supine rest, followed by 1 h of PS only (control [CON] trial), or 20 min of EMS to the lower extremities at 50% of the maximum tolerance intensity during PS (EMS trial). Flow-mediated dilation (FMD) of the BA was measured before and 30 min after PS, and normalized FMD (nFMD) was calculated. RESULTS The nFMD of the CON trial significantly decreased 30 min after PS completion (6.21% ± 1.13%) compared with that before PS (7.26% ± 0.73%), and there was no significant change in the EMS trial before and after PS. The EMS trial showed a significant increase in the nFMD 30 min after PS completion (1.14 ± 0.77) compared with that before PS (0.84 ± 0.43). However, no significant difference was observed in the CON trials. CONCLUSION Passive contraction of the lower extremity muscles by EMS increases BA nFMD, suggesting that prolonged sedentary lower extremity EMS use may reduce the risk of vascular endothelial dysfunction.
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Affiliation(s)
- Mizuki ISHIKAWA
- Department of Physical Therapy, Faculty of Health Science, Osaka Yukioka College of Health Science, Japan
| | - Hajime MIURA
- Laboratory for Applied Physiology, Institutes of Socio-Arts and Sciences, Tokushima University, Japan
| | - Yasuaki TAMURA
- Department of Rehabilitation Medicine, Tokushima Prefecture Naruto Hospital, Japan
| | - Ayako MURAKAMI
- Department of Health and Nutrition, Shikoku University, Japan
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Hamaoka T, Blaha C, Luck JC, Leuenberger UA, Sinoway LI, Cui J. Acute effects of sublingual nitroglycerin on cardiovagal and sympathetic baroreflex sensitivity. Am J Physiol Regul Integr Comp Physiol 2021; 321:R525-R536. [PMID: 34378422 DOI: 10.1152/ajpregu.00304.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of nitroglycerin (glyceryl trinitrate, GTN) on baroreflex sensitivity (BRS) are incompletely understood. Moreover, there are no reports evaluating the acute responses in both the sympathetic BRS (SBRS) and the cardiovagal BRS (CBRS) to the administration of sublingual GTN. We hypothesized that sublingual GTN modulates both CBRS and SBRS. In 10 healthy subjects, beat-to-beat heart rate (HR), blood pressure (BP) and muscle sympathetic nerve activity (MSNA) were recorded before and for 10 min after sublingual administration of GTN 0.4 mg. SBRS was evaluated from the relationship between spontaneous variations in diastolic BP and MSNA. CBRS was assessed with the sequence technique. These variables were assessed during baseline, during min 3rd - 6th (Post A) and 7th -10th min (Post B) after GTN administration. Two min after GTN administration, MSNA increased significantly and remained significantly elevated during recording. Compared to baseline, CBRS decreased significantly (Post A: 12.9 ± 1.6 to 7.1 ± 1.0 ms/mmHg, P < 0.05), while SBRS increased significantly (Post A: 0.8 ± 0.2 to 1.5 ± 0.2 units・beat-1・mmHg-1, P < 0.05) with an upward shift of the operating point. There were no differences in these variables between Post A and B. A clinical dose of GTN increased MSNA rapidly through effects on both CBRS and SBRS. These effects should be kept in mind when nitrates are used to clinically treat chest pain and acute coronary syndromes and used as vasodilators in experimental settings.
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Affiliation(s)
- Takuto Hamaoka
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Cheryl Blaha
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - J Carter Luck
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Urs A Leuenberger
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Lawrence I Sinoway
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
| | - Jian Cui
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA, United States
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Cui J, Blaha C, Leuenberger UA, Sinoway LI. Sympathetic activation due to limb venous distension is preserved during muscle metaboreceptor stimulation. Am J Physiol Regul Integr Comp Physiol 2021; 321:R21-R28. [PMID: 33978490 DOI: 10.1152/ajpregu.00305.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Venous saline infusions in an arterially occluded forearm evoke reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP) in humans (venous distension reflex). It is unclear if the inputs from metabolically sensitive skeletal muscle afferents (i.e., muscle metaboreflex) would modify the venous distension reflex. We hypothesized that muscle metaboreceptor stimulation might augment the venous distension reflex. BP (Finapres), heart rate (ECG), and MSNA (microneurography) were assessed in 18 young healthy subjects. In trial A, saline (5% forearm volume) was infused into the veins of an arterially occluded arm (nonhandgrip trial). In trial B, subjects performed 2-min static handgrip followed by postexercise circulatory occlusion (PECO) of the arm. During PECO, saline was infused into the veins of the arm (handgrip trial). In trial A, the infusion increased MSNA and BP as expected (both P < 0.001). In trial B, handgrip significantly raised MSNA, BP, and venous lactic acid concentrations. Venous saline infusion during PECO further raised MSNA and BP (both P < 0.001). The changes in MSNA (Δ8.6 ± 1.5 to Δ10.6 ± 1.8 bursts/min, P = 0.258) and mean arterial pressure (P = 0.844) evoked by the infusion during PECO were not significantly different from those in the nonhandgrip trial. These observations indicate that venous distension reflex responses are preserved during sympathetic activation mediated by the muscle metaboreflex.
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Affiliation(s)
- Jian Cui
- Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Cheryl Blaha
- Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Urs A Leuenberger
- Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
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Fudim M, Sobotka PA, Dunlap ME. Extracardiac Abnormalities of Preload Reserve: Mechanisms Underlying Exercise Limitation in Heart Failure with Preserved Ejection Fraction, Autonomic Dysfunction, and Liver Disease. Circ Heart Fail 2021; 14:e007308. [PMID: 33464948 DOI: 10.1161/circheartfailure.120.007308] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
While many of the cardiac limitations to exercise performance are now well-characterized, extracardiac limitations to exercise performance have been less well recognized but are nevertheless important. We propose that abnormalities of cardiac preload reserve represents an under-recognized but common cause of exercise limitations. We further propose that mechanistic links exist between conditions as seemingly disparate as heart failure with preserved ejection fraction, nonalcoholic fatty liver disease, and pelvic venous compression/obstruction syndromes (eg, May-Thurner). We conclude that extracardiac abnormalities of preload reserve serve as a major pathophysiologic mechanism underlying these and other disease states.
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Affiliation(s)
- Marat Fudim
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC (M.F.). Duke Clinical Research Institute, Durham, NC (M.F.)
| | - Paul A Sobotka
- Affiliated Faculty, Department of Medicine, Division of Cardiology, The Ohio State University, Columbus (P.A.S.)
| | - Mark E Dunlap
- Heart and Vascular Center, MetroHealth Campus of Case Western Reserve University, Cleveland, OH (M.E.D.)
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9
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Cui J, Blaha C, Herr MD, Sinoway LI. Lower-limb venous distension reflex and orthostatic tolerance in young healthy humans. Am J Physiol Regul Integr Comp Physiol 2020; 319:R142-R147. [PMID: 32663039 DOI: 10.1152/ajpregu.00269.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Earlier reports suggest that limb venous distension evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP) (i.e., venous distension reflex). Our recent report also shows that suction of arterially occluded limb evokes venous distension reflex. We postulate that the venous distension reflex contributes to autonomic responses to orthostatic stress. In this study, we hypothesized that orthostatic tolerance would be linked to the MSNA response seen with lower limb suction. Fifteen healthy subjects were tested in the supine position. Negative pressure (-100 mmHg) was applied on an arterially occluded lower limb for 2 min. MSNA from the peroneal nerve in the limb not exposed to suction, ECG, and BP (Finometer) was recorded throughout the study. Limb occlusion without suction was used as a control trial. In a separate visit, the individual's orthostatic tolerance was assessed using a graded lower body negative pressure (LBNP) tolerance test. Mean arterial BP and MSNA (18.6 ± 1.9 to 23.6 ± 2.0 bursts/min) significantly (both P < 0.05) increased during limb suction. Orthostatic tolerance index positively correlated (R = 0.636, P = 0.011) with the MSNA response seen with suction during occlusion. Since the venous distension reflex strength correlates with the level of orthostatic tolerance, we speculate that lower-limb venous distension reflex engagement increases the sympathetic responses during orthostatic challenge and serves to maintain BP with postural stress.
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Affiliation(s)
- Jian Cui
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Cheryl Blaha
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Michael D Herr
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
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10
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Klassen SA, Moir ME, Usselman CW, Shoemaker JK. Heterogeneous baroreflex control of sympathetic action potential subpopulations in humans. J Physiol 2020; 598:1881-1895. [PMID: 32091132 DOI: 10.1113/jp279326] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 02/21/2020] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Emission patterns in muscle sympathetic nerve activity stem from differently sized action potential (AP) subpopulations that express varying discharge probabilities. The mechanisms governing these firing behaviours are unclear. This study investigated the hypothesis that the arterial baroreflex exerts varying control over the different AP subpopulations. During baseline, medium APs expressed the greatest baroreflex slopes, while small and large APs exhibited weaker slopes. On going from baseline to lower body negative pressure (LBNP; simulated orthostatic stress), baroreflex slopes for some clusters of medium APs expressed the greatest increase, while slopes for large APs also increased but to a lesser degree. A subpopulation of previously silent larger APs was recruited with LBNP but these APs expressed weak baroreflex slopes. The arterial baroreflex heterogeneously regulates sympathetic AP subpopulations, exerting its strongest effect over medium APs. Weak baroreflex mechanisms govern the recruitment of latent larger AP subpopulations during orthostatic stress. ABSTRACT Muscle sympathetic nerve activity (MSNA) occurs primarily in bursts of action potentials (AP) with subpopulations that differ in size and discharge probabilities. The mechanisms determining these discharge patterns remain unclear. This study investigated the hypothesis that variations in AP discharge are due to subpopulation-specific baroreflex control. We employed multi-unit microneurography and a continuous wavelet analysis approach to extract sympathetic APs in 12 healthy individuals during baseline (BSL) and lower body negative pressure (LBNP; -40, -60, -80 mmHg). For each AP cluster, the baroreflex threshold slope was measured from the linear regression between AP probability (%) and diastolic blood pressure (mmHg). During BSL, the baroreflex exerted non-uniform regulation over AP subpopulations: medium-sized AP clusters expressed the greatest slopes while clusters of small and large APs expressed weaker slopes. On going from BSL to LBNP, the baroreflex slopes for each AP subpopulation were modified differently. Baroreflex slopes (%/mmHg) for some medium APs (cluster 5: -4.4 ± 4 to -9.1 ± 5) expressed the greatest increase with LBNP, while slopes for large APs (cluster 9: -1.3 ± 1 to -2.6 ± 2) also increased, but to a lesser degree. Slopes for small APs present at BSL exhibited reductions with LBNP (cluster 2: -3.9 ± 3 to -2.2 ± 3). Larger previously silent AP clusters recruited with LBNP expressed weak baroreflex regulation (cluster 14: -0.9 ± 1%/mmHg). The baroreflex exerts the strongest control over medium-sized APs. Augmenting baroreflex gain and upward resetting of discrete AP subpopulations active at BSL, as well as recruiting larger previously silent APs with weak baroreflex control, facilitates elevated MSNA during orthostatic stress.
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Affiliation(s)
- Stephen A Klassen
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, Canada
| | - M Erin Moir
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, Canada
| | - Charlotte W Usselman
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, Canada.,Department of Kinesiology and Physical Education, McGill University, Canada
| | - J Kevin Shoemaker
- Neurovascular Research Laboratory, School of Kinesiology, University of Western Ontario, Canada.,Department of Physiology and Pharmacology, University of Western Ontario, Canada
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11
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Mansur DE, Campos MO, Mattos JD, Paiva ACS, Rocha MP, Videira RLR, Macefield VG, Nóbrega ACL, Fernandes IA. Muscle sympathetic nerve activity and hemodynamic responses to venous distension: does sex play a role? Am J Physiol Heart Circ Physiol 2018; 316:H734-H742. [PMID: 30592900 DOI: 10.1152/ajpheart.00702.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peripheral venous distension mechanically stimulates type III/IV sensory fibers in veins and evokes pressor and sympathoexcitatory reflex responses in humans. As young women have reduced venous compliance and impaired sympathetic transduction, we tested the hypothesis that pressor and sympathoexcitatory responses to venous distension may be attenuated in women compared with men. Mean arterial pressure (photoplethysmography), heart rate (HR), stroke volume (SV; Modelflow), cardiac output (CO = HR × SV), muscle sympathetic nerve activity (MSNA), femoral artery blood flow, and femoral artery conductance (Doppler ultrasound) were quantified in eight men (27 ± 4 yr) and nine women (28 ± 4 yr) before [control (CON)], during (INF), and immediately after (post-INF) a local infusion of saline [5% of the total forearm volume (30 ml/min); the infusion time was 2 ± 1 and 1 ± 1 min ( P = 0.0001) for men and women, respectively] through a retrograde catheter inserted into an antecubital vein, to which venous drainage and arterial supply had been occluded. Mean arterial pressure increased during and after infusion in both groups (vs. the CON group, P < 0.05), but women showed a smaller pressor response in the post-INF period (Δ+7.2 ± 2.0 vs. Δ+18.3 ± 3.9 mmHg in men, P = 0.019). MSNA increased and femoral artery conductance decreased similarly in both groups (vs. the CON group, P < 0.05) at post-INF. Although HR changes were similar, increases in SV (Δ+20.4 ± 8.6 vs. Δ+2.6 ± 2.7 ml, P = 0.05) and CO (Δ+0.84 ± 0.17 vs. Δ+0.34 ± 0.10 l/min, P = 0.024) were greater in men compared with women. Therefore, venous distension evokes a smaller pressor response in young women due to attenuated cardiac adjustments rather than reduced venous compliance or sympathetic transduction. NEW & NOTEWORTHY We found that the pressor response to venous distension was attenuated in young women compared with age-matched men. This was due to attenuated cardiac adjustments rather than reduced venous compliance, sympathetic activation, or impaired transduction and vascular control. Collectively, these findings suggest that an attenuated venous distension reflex could be involved in orthostatic intolerance in young women.
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Affiliation(s)
- Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Adrielle C S Paiva
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | | | - Vaughan G Macefield
- College of Medicine, Mohammed Bin Rashid University of Health and Medicine , Dubai , United Arab Emirates.,Baker Heart and Diabetes Institute , Melbourne, Victoria , Australia
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil
| | - Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University , Niterói , Brazil.,NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília , Brasília , Brazil
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12
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Stavres J, Singer TJ, Brochetti A, Kilbane MJ, Brose SW, McDaniel J. The Feasibility of Blood Flow Restriction Exercise in Patients With Incomplete Spinal Cord Injury. PM R 2018; 10:1368-1379. [DOI: 10.1016/j.pmrj.2018.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/07/2018] [Accepted: 05/12/2018] [Indexed: 01/09/2023]
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13
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Bud Craig AD. Central neural substrates involved in temperature discrimination, thermal pain, thermal comfort, and thermoregulatory behavior. HANDBOOK OF CLINICAL NEUROLOGY 2018; 156:317-338. [PMID: 30454598 DOI: 10.1016/b978-0-444-63912-7.00019-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A phylogenetically novel pathway that emerged with primate encephalization is described, which conveys high-fidelity cutaneous thermosensory activity in "labeled lines" to a somatotopic map in the dorsal posterior insular cortex. It originates in lamina I of the superficial dorsal horn and ascends by way of the lateral spinothalamic tract and a distinct region in posterolateral thalamus. It evolved from the homeostatic sensory activity that represents the physiologic (interoceptive) condition of the body and drives the central autonomic network, which underlies all affective feelings from the body. Accordingly, human discriminative thermal sensations are accompanied by thermally motivated behaviors and thermal feelings of comfort or discomfort (unless neutral), which evidence suggests are associated with activity in the insular, cingulate, and orbitofrontal cortices, respectively. Yet, the substrates for thermoregulatory behavior have not been established, and several strong candidates (including the hypothalamus and the bed nucleus of the stria terminalis) are discussed. Finally, the neural underpinnings for relationships between thermal affect and social feelings (warm-positive/cold-negative) are addressed, including the association of hyperthermia with clinical depression.
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Affiliation(s)
- Arthur D Bud Craig
- Atkinson Research Laboratory, Barrow Neurological Institute, Phoenix, AZ, United States.
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14
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Lin J, Chudasama N, Hayashi Y, Hawk C, Ramnauth SD, Wong KY, Harxhi A, Onat D, Wakabayashi M, Uriel N, Jorde UP, LeJemtel TH, Sabbah HN, Demmer RT, Colombo PC. Peripheral venous congestion causes time- and dose-dependent release of endothelin-1 in humans. Physiol Rep 2017; 5:5/6/e13118. [PMID: 28320895 PMCID: PMC5371548 DOI: 10.14814/phy2.13118] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 01/08/2023] Open
Abstract
Endothelin‐1 (ET‐1) is a pivotal mediator of vasoconstriction and inflammation in congestive states such as heart failure (HF) and chronic kidney disease (CKD). Whether peripheral venous congestion (VC) increases plasma ET‐1 at pressures commonly seen in HF and CKD patients is unknown. We seek to characterize whether peripheral VC promotes time‐ and dose‐dependent increases in plasma ET‐1 and whether these changes are sustained after decongestion. We used a randomized, cross‐over design in 20 healthy subjects (age 30 ± 7 years). To experimentally model VC, venous pressure was increased to either 15 or 30 mmHg (randomized at first visit) above baseline by inflating a cuff around the subject's dominant arm; the nondominant arm served as a noncongested control. We measured plasma ET‐1 at baseline, after 20, 60 and 120 min of VC, and finally at 180 min (60 min after cuff release and decongestion). Plasma ET‐1 progressively and significantly increased over 120 min in the congested arm relative to the control arm and to baseline values. This effect was dose‐dependent: ET‐1 increased by 45% and 100% at VC doses of 15 and 30 mmHg, respectively (P < 0.05), and declined after 60 min of decongestion though remaining significantly elevated compared to baseline. In summary, peripheral VC causes time‐ and dose‐dependent increases in plasma ET‐1. Of note, the lower dose of 15 mmHg (more clinically relevant to HF and CKD patients) was sufficient to raise ET‐1. These findings support the potentially contributory, not merely consequential, role of VC in the pathophysiology of HF and CKD.
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Affiliation(s)
- Jeffrey Lin
- Columbia University Medical Center, New York, New York
| | | | - Yacki Hayashi
- Columbia University Medical Center, New York, New York
| | | | | | - Ka Yuk Wong
- Columbia University Medical Center, New York, New York
| | - Ante Harxhi
- Columbia University Medical Center, New York, New York
| | - Duygu Onat
- Columbia University Medical Center, New York, New York
| | | | - Nir Uriel
- Columbia University Medical Center, New York, New York
| | | | | | | | - Ryan T Demmer
- Columbia University Medical Center, New York, New York
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15
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Cardiovascular Responses to Skeletal Muscle Stretching: “Stretching” the Truth or a New Exercise Paradigm for Cardiovascular Medicine? Sports Med 2017; 47:2507-2520. [DOI: 10.1007/s40279-017-0768-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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16
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Watanabe N, Hotta H. Heart Rate Changes in Response to Mechanical Pressure Stimulation of Skeletal Muscles Are Mediated by Cardiac Sympathetic Nerve Activity. Front Neurosci 2017; 10:614. [PMID: 28119562 PMCID: PMC5222799 DOI: 10.3389/fnins.2016.00614] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 12/26/2016] [Indexed: 12/01/2022] Open
Abstract
Stimulation of mechanoreceptors in skeletal muscles such as contraction and stretch elicits reflexive autonomic nervous system changes which impact cardiovascular control. There are pressure-sensitive mechanoreceptors in skeletal muscles. Mechanical pressure stimulation of skeletal muscles can induce reflex changes in heart rate (HR) and blood pressure, although the neural mechanisms underlying this effect are unclear. We examined the contribution of cardiac autonomic nerves to HR responses induced by mechanical pressure stimulation (30 s, ~10 N/cm2) of calf muscles in isoflurane-anesthetized rats. Animals were artificially ventilated and kept warm using a heating pad and lamp, and respiration and core body temperature were maintained within physiological ranges. Mechanical stimulation was applied using a stimulation probe 6 mm in diameter with a flat surface. Cardiac sympathetic and vagus nerves were blocked to test the contribution of the autonomic nerves. For sympathetic nerve block, bilateral stellate ganglia, and cervical sympathetic nerves were surgically sectioned, and for vagus nerve block, the nerve was bilaterally severed. In addition, mass discharges of cardiac sympathetic efferent nerve were electrophysiologically recorded. Mechanical stimulation increased or decreased HR in autonomic nerve-intact rats (range: −56 to +10 bpm), and the responses were negatively correlated with pre-stimulus HR (r = −0.65, p = 0.001). Stimulation-induced HR responses were markedly attenuated by blocking the cardiac sympathetic nerve (range: −9 to +3 bpm, p < 0.0001) but not the vagus nerve (range: −75 to +30 bpm, p = 0.17). In the experiments with cardiac sympathetic efferent nerve activity recordings, mechanical stimulation increased, or decreased the frequency of sympathetic nerve activity in parallel with HR (r = 0.77, p = 0.0004). Furthermore, the changes in sympathetic nerve activity were negatively correlated with its tonic level (r = −0.62, p = 0.0066). These results suggest that cardiac sympathetic nerve activity regulates HR responses to muscle mechanical pressure stimulation and the direction of HR responses depends on the tonic level of the nerve activity, i.e., bradycardia occurs when the tonic activity is high and tachycardia occurs when the activity is low.
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Affiliation(s)
- Nobuhiro Watanabe
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology Tokyo, Japan
| | - Harumi Hotta
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology Tokyo, Japan
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17
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Morishima T, Restaino RM, Walsh LK, Kanaley JA, Fadel PJ, Padilla J. Prolonged sitting-induced leg endothelial dysfunction is prevented by fidgeting. Am J Physiol Heart Circ Physiol 2016; 311:H177-82. [PMID: 27233765 DOI: 10.1152/ajpheart.00297.2016] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/19/2016] [Indexed: 11/22/2022]
Abstract
Prolonged sitting impairs endothelial function in the leg vasculature, and this impairment is thought to be largely mediated by a sustained reduction in blood flow-induced shear stress. Indeed, preventing the marked reduction of shear stress during sitting with local heating abolishes the impairment in popliteal artery endothelial function. Herein, we tested the hypothesis that sitting-induced reductions in shear stress and ensuing endothelial dysfunction would be prevented by periodic leg movement, or "fidgeting." In 11 young, healthy subjects, bilateral measurements of popliteal artery flow-mediated dilation (FMD) were performed before and after a 3-h sitting period during which one leg was subjected to intermittent fidgeting (1 min on/4 min off) while the contralateral leg remained still throughout and served as an internal control. Fidgeting produced a pronounced increase in popliteal artery blood flow and shear rate (prefidgeting, 33.7 ± 2.6 s(-1) to immediately postfidgeting, 222.7 ± 28.3 s(-1); mean ± SE; P < 0.001) that tapered off during the following 60 s. Fidgeting did not alter popliteal artery blood flow and shear rate of the contralateral leg, which was subjected to a reduction in blood flow and shear rate throughout the sitting period (presit, 71.7 ± 8.0 s(-1) to 3-h sit, 20.2 ± 2.9 s(-1); P < 0.001). Popliteal artery FMD was impaired after 3 h of sitting in the control leg (presit, 4.5 ± 0.3% to postsit: 1.6 ± 1.1%; P = 0.039) but improved in the fidgeting leg (presit, 3.7 ± 0.6% to postsit, 6.6 ± 1.2%; P = 0.014). Collectively, the present study provides evidence that prolonged sitting-induced leg endothelial dysfunction is preventable with small amounts of leg movement while sitting, likely through the intermittent increases in vascular shear stress.
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Affiliation(s)
- Takuma Morishima
- Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan; Japan Society for the Promotion of Science, Chiyoda, Tokyo, Japan
| | - Robert M Restaino
- Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Lauren K Walsh
- Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Jill A Kanaley
- Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Paul J Fadel
- Kinesiology, University of Texas-Arlington, Arlington, Texas
| | - Jaume Padilla
- Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; and Child Health, University of Missouri, Columbia, Missouri
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18
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Matthews EL, Brian MS, Coyle DE, Edwards DG, Stocker SD, Wenner MM, Farquhar WB. Peripheral venous distension elicits a blood pressure raising reflex in young and middle-aged adults. Am J Physiol Regul Integr Comp Physiol 2016; 310:R1128-33. [PMID: 27053648 DOI: 10.1152/ajpregu.00438.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 03/31/2016] [Indexed: 11/22/2022]
Abstract
Distension of peripheral veins in humans elicits a pressor and sympathoexcitatory response that is mediated through group III/IV skeletal muscle afferents. There is some evidence that autonomic reflexes mediated by these sensory fibers are blunted with increasing age, yet to date the venous distension reflex has only been studied in young adults. Therefore, we tested the hypothesis that the venous distension reflex would be attenuated in middle-aged compared with young adults. Nineteen young (14 men/5 women, 25 ± 1 yr) and 13 middle-aged (9 men/4 women, 50 ± 2 yr) healthy normotensive participants underwent venous distension via saline infusion through a retrograde intravenous catheter in an antecubital vein during limb occlusion. Beat-by-beat blood pressure, muscle sympathetic nerve activity (MSNA), and model flow-derived cardiac output (Q), and total peripheral resistance (TPR) were recorded throughout the trial. Mean arterial pressure (MAP) increased during the venous distension in both young (baseline 83 ± 2, peak 94 ± 3 mmHg; P < 0.05) and middle-aged adults (baseline 88 ± 2, peak 103 ± 3 mmHg; P < 0.05). MSNA also increased in both groups [young: baseline 886 ± 143, peak 1,961 ± 242 arbitrary units (AU)/min; middle-aged: baseline 1,164 ± 225, peak 2,515 ± 404 AU/min; both P < 0.05]. TPR (P < 0.001), but not Q (P = 0.76), increased during the trial. However, the observed increases in blood pressure, MSNA, and TPR were similar between young and middle-aged adults. Additionally, no correlation was found between age and the response to venous distension (all P > 0.05). These findings suggest that peripheral venous distension elicits a pressor and sympathetic response in middle-aged adults similar to the response observed in young adults.
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Affiliation(s)
- Evan L Matthews
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
| | - Michael S Brian
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
| | - Dana E Coyle
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
| | - David G Edwards
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
| | - Sean D Stocker
- Departments of Physiology and Neural and Behavioral Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Megan M Wenner
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
| | - William B Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware; and
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19
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Sternberg Z. Promoting sympathovagal balance in multiple sclerosis; pharmacological, non-pharmacological, and surgical strategies. Autoimmun Rev 2016; 15:113-23. [DOI: 10.1016/j.autrev.2015.04.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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20
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Colombo PC, Doran AC, Onat D, Wong KY, Ahmad M, Sabbah HN, Demmer RT. Venous congestion, endothelial and neurohormonal activation in acute decompensated heart failure: cause or effect? Curr Heart Fail Rep 2016; 12:215-22. [PMID: 25740404 DOI: 10.1007/s11897-015-0254-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Venous congestion and endothelial and neurohormonal activation are known to occur in acute decompensated heart failure (ADHF), yet the temporal role of these processes in the pathophysiology of decompensation is not fully understood. Conventional wisdom presumes congestion to be a consequence of worsening cardiovascular function; however, the biomechanically driven effects of venous congestion are biologically plausible contributors to ADHF that remain largely unexplored in vivo. Recent experimental evidence from human models suggests that fluid accumulation and venous congestion are not simply consequences of poor cardiovascular function, but rather are fundamental pro-oxidant, pro-inflammatory, and hemodynamic stimuli that contribute to acute decompensation. The latest advances in the monitoring of volume status using implantable devices allow for the detection of venous congestion before symptoms arise. This may ultimately lead to improved treatment strategies including not only diuretics, but also specific, adjuvant interventions to counteract endothelial and neurohormonal activation during early preclinical decompensation.
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Affiliation(s)
- Paolo C Colombo
- Division of Cardiology, College of Physicians & Surgeons, Department of Medicine, Columbia University, 622 West 168th Street, PH 12-134, New York, NY, 10032, USA,
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21
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Impaired Neurovisceral Integration of Cardiovascular Modulation Contributes to Multiple Sclerosis Morbidities. Mol Neurobiol 2016; 54:362-374. [DOI: 10.1007/s12035-015-9599-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 12/01/2015] [Indexed: 12/16/2022]
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22
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Cui J, Muller MD, Blaha C, Kunselman AR, Sinoway LI. Seasonal variation in muscle sympathetic nerve activity. Physiol Rep 2015; 3:3/8/e12492. [PMID: 26265752 PMCID: PMC4562578 DOI: 10.14814/phy2.12492] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Epidemiologic data suggest there are seasonal variations in the incidence of severe cardiac events with peak levels being evident in the winter. Whether autonomic indices including muscle sympathetic nerve activity (MSNA) vary with season remains unclear. In this report, we tested the hypothesis that resting MSNA varies with the seasons of the year with peak levels evident in the winter. We analyzed the supine resting MSNA in 60 healthy subjects. Each subject was studied during two, three, or four seasons (total 237 visits). MSNA burst rate in the winter (21.0 ± 6.8 burst/min, mean ± SD) was significantly greater than in the summer (13.5 ± 5.8 burst/min, P < 0.001), the spring (17.1 ± 9.0 burst/min, P = 0.03), and the fall (17.9 ± 7.7 burst/min, P = 0.002). There was no significant difference in MSNA for other seasonal comparisons. The results suggest that resting sympathetic nerve activity varies along the seasons, with peak levels evident in the winter. We speculate that the seasonal changes in sympathetic activity may be a contribution to the previously observed seasonal variations in cardiovascular morbidity and mortality.
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Affiliation(s)
- Jian Cui
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Matthew D Muller
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Cheryl Blaha
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Allen R Kunselman
- Division of Biostatistics and Bioinformatics, Department of Public Health Sciences, Pennsylvania State University College of Medicine Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine Milton S. Hershey Medical Center, Hershey, Pennsylvania
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Cui J, Blaha C, Herr MD, Drew RC, Muller MD, Sinoway LI. Limb suction evoked during arterial occlusion causes systemic sympathetic activity in humans. Am J Physiol Regul Integr Comp Physiol 2015; 309:R482-8. [PMID: 26136530 DOI: 10.1152/ajpregu.00117.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/29/2015] [Indexed: 12/30/2022]
Abstract
Venous saline infusions in an arterially occluded forearm evokes reflex increases in muscle sympathetic nerve activity (MSNA) and blood pressure (BP). We hypothesized that the application of suction to the human limbs would activate this venous distension reflex and raise sympathetic outflow. We placed airtight pressure tanks and applied 100 mmHg negative pressure to an arterially occluded limb (occlusion and suction, O&S) to induce tissue deformation without fluid translocation. BP, heart rate (HR), and MSNA were assessed in 19 healthy subjects during 2 min of arm or leg O&S. Occlusion without suction served as a control. During a separate visit, saline (5% forearm volume) was infused into veins of the arterially occluded arm (n = 13). The O&S increased limb circumference, MSNA burst rate (arm: Δ6.7 ± 0.7; leg: Δ6.8 ± 0.7 bursts/min), and total activity (arm: Δ199 ± 14; leg: Δ172 ± 22 units/min) and BP (arm: Δ4.3 ± 0.3; leg: Δ9.4 ± 1.4 mmHg) from the baseline. The MSNA and BP responses during arm O&S correlated with those during leg O&S. Occlusion alone had no effect on MSNA and BP. MSNA (r = 0.607) responses during arm O&S correlated with those evoked by the saline infusion into the arm. These correlations suggest that sympathetic activation during limb O&S is likely, at least partially, to be evoked via the venous distension reflex. These data suggest that suction of an occluded limb evokes sympathetic activation and that the limb venous distension reflex exists in arms and legs of normal humans.
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Affiliation(s)
- Jian Cui
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Cheryl Blaha
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Michael D Herr
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Rachel C Drew
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Matthew D Muller
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
| | - Lawrence I Sinoway
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, Pennsylvania
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24
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Affiliation(s)
- Zohara Sternberg
- Department of Neurology, Stroke Center, Buffalo Medical Center, Buffalo, NY, USA
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25
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Arata M, Sternberg Z. Transvascular autonomic modulation: a modified balloon angioplasty technique for the treatment of autonomic dysfunction in multiple sclerosis patients. J Endovasc Ther 2015; 21:417-28. [PMID: 24915592 DOI: 10.1583/13-4605mr.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To describe the use of transvascular autonomic modulation (TVAM) to improve cardiovascular autonomic nervous system (ANS) dysfunction in multiple sclerosis (MS) patients, comparing the safety and efficacy of this modified technique with traditional balloon angioplasty. METHODS Twenty-one MS patients (11 men; mean age 48.7±13.0 years) who presented with symptoms of cardiovascular ANS dysfunction underwent TVAM. These patients were compared with age/sex-matched MS patients (10 men; 49.3±11.1 years) in the same stages of the disease who presented with chronic cerebrospinal venous insufficiency (CCSVI) and who underwent venous balloon angioplasty. TVAM involved the coupling of balloon angioplasty of the internal jugular veins with the application of external manual compression and dilation of the azygos and renal veins; unlike traditional angioplasty for CCSVI, which treats only abnormal veins (≥50% stenosis or static valve), all targeted vessels were treated with TVAM regardless of the presence of an abnormality. The effect of TVAM on ANS function was indicated by determining heart rate variability based on the electrocardiographic R-R interval lengths using vector analysis to derive the mean circular resultant (MCR) and the expiration/inspiration (E/I) ratio, the Valsalva ratio, and the 30:15 postural ratio at 24 hours after intervention. RESULTS Left renal vein compression was common among the TVAM patients and resulted in ≥50% luminal compromise in 10 of 21 patients. Azygos vein abnormalities (a static valve) were identified in 5 patients. Overall, 18 patients met the diagnostic criteria for CCSVI with at least one lesion >50%, but only 10 lesions were considered treatable by traditional balloon angioplasty. After intervention, the R-R interval values, including the 30:15 postural ratio (p=0.01), the MCR (p=0.1), and E/I ratio (p=0.1), were higher for the TVAM patients compared to the control group. The safety profile of the TVAM procedure was similar to that of traditional balloon angioplasty. CONCLUSION The combination of balloon angioplasty of anatomically normal veins coupled with external compression during dilation of these veins can improve indicators of ANS dysfunction. The safety and efficacy of TVAM in MS patients observed in this pilot study is encouraging, paving the way for the treatment of dysautonomia in pathological states other than MS. Further studies should investigate TVAM in a larger MS cohort.
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Affiliation(s)
- Michael Arata
- Synergy Health Concepts, Newport Beach, California, USA
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26
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Lindenberger M, Länne T. Slower lower limb blood pooling in young women with orthostatic intolerance. Exp Physiol 2015; 100:2-11. [PMID: 25557726 DOI: 10.1113/expphysiol.2014.082867] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 10/20/2014] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Orthostatic stress is mostly caused by venous blood pooling in the lower limbs. Venous distension elicits sympathetic responses, and increased distension speed enhances the cardiovascular response. We examine whether lower limb blood pooling rate during lower body negative pressure is linked to orthostatic intolerance. What is the main finding and its importance? A similar amount of blood was pooled in the lower limb, but at a slower rate in women who developed signs of orthostatic intolerance. The difference in blood pooling rate increased with orthostatic stress and was most prominent at a presyncope-inducing level of lower body negative pressure. The findings have implications for the pathophysiology as well as treatment of orthostatic intolerance. Vasovagal syncope is common in young women, but its aetiology remains elusive. Orthostatic stress-induced lower limb blood pooling is linked with central hypovolaemia and baroreceptor unloading. Venous distension in the arm elicits a sympathetic response, which is enhanced with more rapid distension. Our aim was to study both the amount and the speed of lower limb pooling during orthostatic stress and its effects on compensatory mechanisms to maintain cardiovascular homeostasis in women with orthostatic intolerance. Twenty-seven healthy women, aged 20-27 years, were subjected to a lower body negative pressure (LBNP) of 11-44 mmHg. Five women developed symptoms of vasovagal syncope (orthostatic intolerant) and were compared with the remaining women, who tolerated LBNP well (orthostatic tolerant). Lower limb blood pooling, blood flow and compensatory mobilization of venous capacitance blood were measured. Lower body negative pressure induced equal lower limb blood pooling in both groups, but at a slower rate in orthostatic intolerant women (e.g. time to 50% of total blood pooling, orthostatic intolerant 44 ± 7 s and orthostatic tolerant 26 ± 2 s; P < 0.001). At presyncope-inducing LBNP, the mobilization of venous capacitance blood was both reduced (P < 0.05) and much slower in orthostatic intolerant women (P = 0.0007). Orthostatic intolerant women elicited blunted arterial vasoconstriction at low-grade LBNP, activating only cardiopulmonary baroreceptors, while orthostatic tolerant women responded with apparent vasoconstriction (P < 0.0001). In conclusion, slower lower limb blood pooling could contribute to orthostatic intolerance in women. Mobilization of venous capacitance blood from the peripheral to the central circulation was both slower and decreased; furthermore, reduced cardiopulmonary baroreceptor sensitivity was found in women who developed orthostatic intolerance. Further studies including women who experience syncope in daily life are needed.
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Affiliation(s)
- Marcus Lindenberger
- Department of Medical and Health Sciences, Linköping University, Linköping, Sweden; Department of Cardiology, County Council of Östergötland, Linköping, Sweden
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Harada D, Asanoi H, Takagawa J, Ishise H, Ueno H, Oda Y, Goso Y, Joho S, Inoue H. Slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with chronic heart failure: from modeling to clinical application. Am J Physiol Heart Circ Physiol 2014; 307:H1159-68. [DOI: 10.1152/ajpheart.00109.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Influences of slow and deep respiration on steady-state sympathetic nerve activity remain controversial in humans and could vary depending on disease conditions and basal sympathetic nerve activity. To elucidate the respiratory modulation of steady-state sympathetic nerve activity, we modeled the dynamic nature of the relationship between lung inflation and muscle sympathetic nerve activity (MSNA) in 11 heart failure patients with exaggerated sympathetic outflow at rest. An autoregressive exogenous input model was utilized to simulate entire responses of MSNA to variable respiratory patterns. In another 18 patients, we determined the influence of increasing tidal volume and slowing respiratory frequency on MSNA; 10 patients underwent a 15-min device-guided slow respiration and the remaining 8 had no respiratory modification. The model predicted that a 1-liter, step increase of lung volume decreased MSNA dynamically; its nadir (−33 ± 22%) occurred at 2.4 s; and steady-state decrease (−15 ± 5%), at 6 s. Actually, in patients with the device-guided slow and deep respiration, respiratory frequency effectively fell from 16.4 ± 3.9 to 6.7 ± 2.8/min ( P < 0.0001) with a concomitant increase in tidal volume from 499 ± 206 to 1,177 ± 497 ml ( P < 0.001). Consequently, steady-state MSNA was decreased by 31% ( P < 0.005). In patients without respiratory modulation, there were no significant changes in respiratory frequency, tidal volume, and steady-state MSNA. Thus slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with high levels of resting sympathetic tone as in heart failure.
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Affiliation(s)
- Daisuke Harada
- The Cardiology Division, Imizu City Hospital, Imizu City, Toyama, Japan; and
| | - Hidetsugu Asanoi
- The Cardiology Division, Imizu City Hospital, Imizu City, Toyama, Japan; and
| | - Junya Takagawa
- The Cardiology Division, Imizu City Hospital, Imizu City, Toyama, Japan; and
| | - Hisanari Ishise
- The Cardiology Division, Imizu City Hospital, Imizu City, Toyama, Japan; and
| | - Hiroshi Ueno
- The Cardiology Division, Imizu City Hospital, Imizu City, Toyama, Japan; and
| | - Yoshitaka Oda
- The Cardiology Division, Toyama University Hospital, Toyama City, Toyama, Japan
| | - Yukiko Goso
- The Cardiology Division, Toyama University Hospital, Toyama City, Toyama, Japan
| | - Shuji Joho
- The Cardiology Division, Toyama University Hospital, Toyama City, Toyama, Japan
| | - Hiroshi Inoue
- The Cardiology Division, Toyama University Hospital, Toyama City, Toyama, Japan
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Circulatory responses to lower body negative pressure in young Afghans and Danes: implications for understanding ethnic effects on blood pressure regulation. Eur J Appl Physiol 2014; 114:2321-9. [PMID: 25059759 DOI: 10.1007/s00421-014-2946-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 06/25/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE We have previously shown that Afghans residing in Denmark for at least 12 years exhibit a lower 24-h ambulatory blood pressure compared to Danes. The purpose of this study was to test the hypothesis that the lower blood pressure reflects attenuated compensatory baroreflex responses in the Afghans. METHODS On a controlled diet (2,822 cal/day, 55-75 mmol + 2 mmol Na+/kg/day), 12 young males of Afghan (Afghans) and 12 young males of Danish (Danes) origin were exposed to a two-step lower body negative pressure (LBNP) protocol of -20 and -50 mmHg, respectively, each of 10-min duration. RESULTS Afghans had lower 24-h systolic blood pressure compared to Danes (115 ± 2 vs. 123 ± 1 mmHg, p < 0.05). Cardiac output and stroke volume were significantly lower in Afghans compared to Danes prior to and during each level of LBNP. However, it decreased to the same extent in both groups during LBNP. During LBNP of -20 mmHg, plasma noradrenaline concentration and plasma renin activity (PRA) increased significantly only in the Afghans. At LBNP of -50 mmHg plasma noradrenaline concentration and PRA both increased significantly and similarly in the two groups. CONCLUSION The lower 24-h ambulatory blood pressure in the Afghans is probably caused by a lower stroke volume, which augmented the circulatory and vasoactive hormonal responses to LBNP in the Afghans. The lower stroke volume in Afghans residing in Denmark compared to that of matched native Danes remains to be explained.
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Immink RV, Pott FC, Secher NH, van Lieshout JJ. Hyperventilation, cerebral perfusion, and syncope. J Appl Physiol (1985) 2013; 116:844-51. [PMID: 24265279 DOI: 10.1152/japplphysiol.00637.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This review summarizes evidence in humans for an association between hyperventilation (HV)-induced hypocapnia and a reduction in cerebral perfusion leading to syncope defined as transient loss of consciousness (TLOC). The cerebral vasculature is sensitive to changes in both the arterial carbon dioxide (PaCO2) and oxygen (PaO2) partial pressures so that hypercapnia/hypoxia increases and hypocapnia/hyperoxia reduces global cerebral blood flow. Cerebral hypoperfusion and TLOC have been associated with hypocapnia related to HV. Notwithstanding pronounced cerebrovascular effects of PaCO2 the contribution of a low PaCO2 to the early postural reduction in middle cerebral artery blood velocity is transient. HV together with postural stress does not reduce cerebral perfusion to such an extent that TLOC develops. However when HV is combined with cardiovascular stressors like cold immersion or reduced cardiac output brain perfusion becomes jeopardized. Whether, in patients with cardiovascular disease and/or defect, cerebral blood flow cerebral control HV-induced hypocapnia elicits cerebral hypoperfusion, leading to TLOC, remains to be established.
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Affiliation(s)
- R V Immink
- Laboratory for Clinical Cardiovascular Physiology, Department of Anatomy, Embryology, and Physiology, AMC Center for Heart Failure Research, Academic Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
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30
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Garvin NM, Levine BD, Raven PB, Pawelczyk JA. Pneumatic antishock garment inflation activates the human sympathetic nervous system by abdominal compression. Exp Physiol 2013; 99:101-10. [DOI: 10.1113/expphysiol.2013.072447] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Cui J, Gao Z, Blaha C, Herr MD, Mast J, Sinoway LI. Distension of central great vein decreases sympathetic outflow in humans. Am J Physiol Heart Circ Physiol 2013; 305:H378-85. [PMID: 23729210 DOI: 10.1152/ajpheart.00019.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Classic canine studies suggest that central great vein distension evokes an autonomic reflex tachycardia (Bainbridge reflex). It is unclear whether central venous distension in humans is a necessary and sufficient stimulus to evoke a reflex increase in heart rate (HR), blood pressure (BP), and muscle sympathetic nerve activity (MSNA). Prior work from our laboratory suggests that limb venous distension evokes a reflex increase in BP and MSNA in humans. We hypothesized that in humans, compared with the limb venous distension, inferior vena cava (IVC) distension would evoke a less prominent increase in HR and MSNA. IVC distension (monitored with ultrasonography) was induced by two methods: 1) head-down tilt (HDT, N = 13); and 2) lower-body positive pressure (LBPP, N = 10). Two minutes of HDT induced IVC distension (Δ2.6 ± 0.2 mm, P < 0.001, ~27% in cross-sectional area), slightly increased mean BP (Δ2.3 ± 0.7 mmHg, P = 0.005), decreased MSNA (Δ5.2 ± 0.8 bursts/min, P < 0.001, N = 10), and did not alter HR (P = 0.37). LBPP induced similar IVC distension, increased BP (Δ2.0 ± 0.7 mmHg, P < 0.01), and did not alter HR (P = 0.34). Thus central venous distension leads to a rapid increase in BP and a subsequent fall in MSNA. Central venous distension does not evoke either bradycardia or tachycardia in humans. The absence of a baroreflex-mediated bradycardia suggests that the Bainbridge reflex is engaged. Clearly, this reflex differs from the powerful sympathoexcitation peripheral venous distension reflex described in humans.
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Affiliation(s)
- Jian Cui
- Pennsylvania State University College of Medicine, Penn State Hershey Heart and Vascular Institute, Milton S. Hershey Medical Center, Hershey, PA 17033, USA
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Muller MD, Mast JL, Cui J, Heffernan MJ, McQuillan PM, Sinoway LI. Tactile stimulation of the oropharynx elicits sympathoexcitation in conscious humans. J Appl Physiol (1985) 2013; 115:71-7. [PMID: 23599399 DOI: 10.1152/japplphysiol.00197.2013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tactile stimulation of the oropharynx (TSO) elicits the gag reflex and increases heart rate (HR) and mean arterial pressure (MAP) in anesthetized patients. However, the interaction between upper-airway defense reflexes and the sympathetic nervous system has not been investigated in conscious humans. In Experiment 1, beat-by-beat measurements of HR, MAP, muscle sympathetic nerve activity (MSNA), and renal vascular resistance (RVR) were measured during TSO and tactile stimulation of the hard palate (Sham) in the supine posture. In Experiment 2, TSO was performed before (pre) and after (post) inhalation of 4% lidocaine via nebulizer. Rate pressure product (RPP) was determined. Compared with Sham, TSO elicited the gag reflex and increased RPP [absolute change (Δ)36 ± 6 vs. 17 ± 5%], MSNA (Δ122 ± 39 vs. 19 ± 19%), and RVR (Δ55 ± 11 vs. 4 ± 4%). This effect occurred within one to two cardiac cycles of TSO. The ΔMAP (12 ± 3 vs. 6 ± 1 mmHg) and the ΔHR (10 ± 3 vs. 3 ± 3 beats/min) were also greater following TSO compared with Sham. Lidocaine inhalation blocked the gag reflex and attenuated increases in MAP (Δpre: 16 ± 2; Δpost: 5 ± 2 mmHg) and HR (Δpre: 12 ± 3; Δpost: 2 ± 2 beats/min) in response to TSO. When mechanically stimulated, afferents in the oropharynx not only serve to protect the airway but also cause reflex increases in MSNA, RVR, MAP, and HR. An augmented sympathoexcitatory response during intubation and laryngoscopy may contribute to perioperative cardiovascular morbidity and mortality.
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Affiliation(s)
- Matthew D Muller
- Penn State Hershey Heart and Vascular Institute, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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