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Hansen AB, Amin SB, Hofstätter F, Mugele H, Simpson LL, Gasho C, Dawkins TG, Tymko MM, Ainslie PN, Villafuerte FC, Hearon CM, Lawley JS, Moralez G. Global Reach 2018: sympathetic neural and hemodynamic responses to submaximal exercise in Andeans with and without chronic mountain sickness. Am J Physiol Heart Circ Physiol 2022; 322:H844-H856. [PMID: 35333117 PMCID: PMC9018046 DOI: 10.1152/ajpheart.00555.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 03/14/2022] [Accepted: 03/14/2022] [Indexed: 11/22/2022]
Abstract
Andeans with chronic mountain sickness (CMS) and polycythemia have similar maximal oxygen uptakes to healthy Andeans. Therefore, this study aimed to explore potential adaptations in convective oxygen transport, with a specific focus on sympathetically mediated vasoconstriction of nonactive skeletal muscle. In Andeans with (CMS+, n = 7) and without (CMS-, n = 9) CMS, we measured components of convective oxygen delivery, hemodynamic (arterial blood pressure via intra-arterial catheter), and autonomic responses [muscle sympathetic nerve activity (MSNA)] at rest and during steady-state submaximal cycling exercise [30% and 60% peak power output (PPO) for 5 min each]. Cycling caused similar increases in heart rate, cardiac output, and oxygen delivery at both workloads between both Andean groups. However, at 60% PPO, CMS+ had a blunted reduction in Δtotal peripheral resistance (CMS-, -10.7 ± 3.8 vs. CMS+, -4.9 ± 4.1 mmHg·L-1·min-1; P = 0.012; d = 1.5) that coincided with a greater Δforearm vasoconstriction (CMS-, -0.2 ± 0.6 vs. CMS+, 1.5 ± 1.3 mmHg·mL-1·min-1; P = 0.008; d = 1.7) and a rise in Δdiastolic blood pressure (CMS-, 14.2 ± 7.2 vs. CMS+, 21.6 ± 4.2 mmHg; P = 0.023; d = 1.2) compared with CMS-. Interestingly, although MSNA burst frequency did not change at 30% or 60% of PPO in either group, at 60% Δburst incidence was attenuated in CMS+ (P = 0.028; d = 1.4). These findings indicate that in Andeans with polycythemia, light intensity exercise elicited similar cardiovascular and autonomic responses compared with CMS-. Furthermore, convective oxygen delivery is maintained during moderate-intensity exercise despite higher peripheral resistance. In addition, the elevated peripheral resistance during exercise was not mediated by greater sympathetic neural outflow, thus other neural and/or nonneural factors are perhaps involved.NEW & NOTEWORTHY During submaximal exercise, convective oxygen transport is maintained in Andeans suffering from polycythemia. Light intensity exercise elicited similar cardiovascular and autonomic responses compared with healthy Andeans. However, during moderate-intensity exercise, we observed a blunted reduction in total peripheral resistance, which cannot be ascribed to an exaggerated increase in muscle sympathetic nerve activity, indicating possible contributions from other neural and/or nonneural mechanisms.
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Affiliation(s)
- Alexander B Hansen
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Sachin B Amin
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Florian Hofstätter
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Hendrik Mugele
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Lydia L Simpson
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Christopher Gasho
- Division of Pulmonary and Critical Care, Department of Medicine, University of Loma Linda, Loma Linda, California
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Michael M Tymko
- Physical Activity and Diabetes Laboratory, Faculty of Kinesiology and Recreation, University of Alberta, Edmonton, Alberta, Canada
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Christopher M Hearon
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas
| | - Justin S Lawley
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
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2
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Li S, Hildreth CM, Rahman AA, Barton SA, Wyse BF, Lim CK, Pilowsky PM, Phillips JK. Renal denervation does not affect hypertension or the renin-angiotensin system in a rodent model of juvenile-onset polycystic kidney disease: clinical implications. Sci Rep 2021; 11:14286. [PMID: 34253766 PMCID: PMC8275789 DOI: 10.1038/s41598-021-93575-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 06/21/2021] [Indexed: 12/17/2022] Open
Abstract
We examined the effect of total and afferent renal denervation (RDN) on hypertension and the renin-angiotensin system (RAS) in a rodent model of juvenile-onset polycystic kidney disease (PKD). Lewis Polycystic Kidney (LPK) and control rats received total, afferent or sham RDN by periaxonal application of phenol, capsaicin or normal saline, respectively, and were monitored for 4-weeks. Afferent RDN did not affect systolic blood pressure (SBP) determined by radiotelemetry in either strain (n = 19) while total RDN significantly reduced SBP in Lewis rats 4-weeks post-denervation (total vs. sham, 122 ± 1 vs. 130 ± 2 mmHg, P = 0.002, n = 25). Plasma and kidney renin content determined by radioimmunoassay were significantly lower in LPK vs. Lewis (plasma: 278.2 ± 6.7 vs. 376.5 ± 11.9 ng Ang I/ml/h; kidney: 260.1 ± 6.3 vs. 753.2 ± 37.9 ng Ang I/mg/h, P < 0.001, n = 26). These parameters were not affected by RDN. Intrarenal mRNA expression levels of renin, angiotensinogen, angiotensin-converting enzyme (ACE)2, and angiotensin II receptor type 1a were significantly lower, whereas ACE1 expression was significantly higher in the LPK vs. Lewis (all P < 0.05, n = 26). This pattern of intrarenal RAS expression was not changed by RDN. In conclusion, RDN does not affect hypertension or the RAS in the LPK model and indicates RDN might not be a suitable antihypertensive strategy for individuals with juvenile-onset PKD.
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Affiliation(s)
- Sheran Li
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Cara M Hildreth
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Ahmed A Rahman
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Sean A Barton
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Benjamin F Wyse
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Chai K Lim
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Paul M Pilowsky
- Discipline of Physiology, School of Medical Sciences, University of Sydney, Sydney, Australia
| | - Jacqueline K Phillips
- Department of Biomedical Sciences, Faculty of Medicine, Human and Health Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
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3
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Holwerda SW, Carter JR, Yang H, Wang J, Pierce GL, Fadel PJ. CORP: Standardizing methodology for assessing spontaneous baroreflex control of muscle sympathetic nerve activity in humans. Am J Physiol Heart Circ Physiol 2021; 320:H762-H771. [PMID: 33275522 PMCID: PMC8082800 DOI: 10.1152/ajpheart.00704.2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 12/28/2022]
Abstract
The use of spontaneous bursts of muscle sympathetic nerve activity (MSNA) to assess arterial baroreflex control of sympathetic nerve activity has seen increased utility in studies of both health and disease. However, methods used for analyzing spontaneous MSNA baroreflex sensitivity are highly variable across published studies. Therefore, we sought to comprehensively examine methods of producing linear regression slopes to quantify spontaneous MSNA baroreflex sensitivity in a large cohort of subjects (n = 150) to support a standardized procedure for analysis that would allow for consistent and comparable results across laboratories. The primary results demonstrated that 1) consistency of linear regression slopes was considerably improved when the correlation coefficient was above -0.70, which is more stringent compared with commonly reported criterion of -0.50, 2) longer recording durations increased the percentage of linear regressions producing correlation coefficients above -0.70 (1 min = 15%, 2 min = 28%, 5 min = 53%, 10 min = 67%, P < 0.001) and reaching statistical significance (1 min = 40%, 2 min = 69%, 5 min = 78%, 10 min = 89%, P < 0.001), 3) correlation coefficients were improved with 3-mmHg versus 1-mmHg and 2-mmHg diastolic blood pressure (BP) bin size, and 4) linear regression slopes were reduced when the acquired BP signal was not properly aligned with the cardiac cycle triggering the burst of MSNA. In summary, these results support the use of baseline recording durations of 10 min, a correlation coefficient above -0.70 for reliable linear regressions, 3-mmHg bin size, and importance of properly time-aligning MSNA and diastolic BP. Together, these findings provide best practices for determining spontaneous MSNA baroreflex sensitivity under resting conditions for improved rigor and reproducibility of results.
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Affiliation(s)
- Seth W Holwerda
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, Kansas
| | - Jason R Carter
- Department of Health and Human Development, Montana State University, Bozeman, Montana
| | - Huan Yang
- Department of Neurology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts
| | - Jing Wang
- College of Nursing, University of Texas at Arlington, Arlington, Texas
| | - Gary L Pierce
- Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
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Nishi EE, Lopes NR, Gomes GN, Perry JC, Sato AYS, Naffah-Mazzacoratti MG, Bergamaschi CT, Campos RR. Renal denervation reduces sympathetic overactivation, brain oxidative stress, and renal injury in rats with renovascular hypertension independent of its effects on reducing blood pressure. Hypertens Res 2018; 42:628-640. [PMID: 30573809 DOI: 10.1038/s41440-018-0171-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 10/19/2018] [Accepted: 10/31/2018] [Indexed: 12/27/2022]
Abstract
The underlying mechanisms by which renal denervation (RD) decreases blood pressure (BP) remain incompletely understood. In this study, we investigated the effects of ischemic kidney denervation on different sympathetic outflows, brain and renal expression of angiotensin-II receptors, oxidative stress and renal function markers in the 2-kidney, 1-clip (2K-1C) rat model. Surgical RD was performed in Wistar male rats 4-5 weeks after clip implantation. After 10 days of RD, BP, and the activity of sympathetic nerves projecting to the contralateral kidney (rSNA) and splanchnic region were partially reduced in 2K-1C rats, with no change in systemic renin-angiotensin system (RAS). To distinguish the effects of RD from the reduction in BP, 2K-1C rats were treated with hydralazine by oral gavage (25 mg/kg/day for 1 week). RD, but not hydralazine, normalized oxidative stress in the sympathetic premotor brain regions and improved intrarenal RAS, renal injury, and proteinuria. Furthermore, different mechanisms led to renal injury and oxidative stress in the ischemic and contralateral kidneys of 2K-1C rats. Injury and oxidative stress in the ischemic kidney were driven by the renal nerves. Although RD attenuated rSNA, injury and oxidative stress persisted in the contralateral kidney, probably due to increased BP. Therefore, nerves from the ischemic kidney at least partially contribute to the increase in BP, sympathetic outflows, brain oxidative stress, and renal alterations in rats with renovascular hypertension. Based on these findings, the reduction in oxidative stress in the brain is a central mechanism that contributes to the effects of RD on Goldblatt hypertension.
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Affiliation(s)
- Erika E Nishi
- Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
| | - Nathalia R Lopes
- Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Guiomar N Gomes
- Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Juliana C Perry
- Department of Psychobiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Alex Y S Sato
- Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Maria G Naffah-Mazzacoratti
- Department of Neurology and Neurosurgery, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Cássia T Bergamaschi
- Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Ruy R Campos
- Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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5
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Gueguen C, Jackson KL, Marques FZ, Eikelis N, Phillips S, Stevenson ER, Charchar FJ, Lambert GW, Davern PJ, Head GA. Renal nerves contribute to hypertension in Schlager BPH/2J mice. Hypertens Res 2018; 42:306-318. [PMID: 30531841 DOI: 10.1038/s41440-018-0147-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 07/30/2018] [Accepted: 08/22/2018] [Indexed: 01/29/2023]
Abstract
Schlager mice (BPH/2J) are hypertensive due to a greater contribution of the sympathetic nervous system (SNS) and renin-angiotensin system (RAS). The kidneys of BPH/2J are hyper-innervated suggesting renal nerves may contribute to the hypertension. We therefore determined the effect of bilateral renal denervation (RD) on hypertension in BPH/2J. Mean arterial pressure (MAP) was measured by radiotelemetry before and for 3 weeks after RD in BPH/2J and BPN/3J. The effects of pentolinium and enalaprilat were examined to determine the contribution of the SNS and RAS, respectively. After 3 weeks, MAP was -10.9 ± 2.1 mmHg lower in RD BPH/2J compared to baseline and -2.1 ± 2.2 mmHg in sham BPH/2J (P < 0.001, n = 8-10). RD had no effect in BPN/3J (P > 0.1). The depressor response to pentolinium was greater in BPH/2J than BPN/3J, but in both cases the response in RD mice was similar to sham. Enalaprilat decreased MAP more in RD BPH/2J compared to sham (-12 vs -3 mmHg, P < 0.001) but had no effect in BPN/3J. RD reduced renal noradrenaline in both strains but more so in BPH/2J. RD reduced renin mRNA and protein, but not plasma renin in BPH/2J to levels comparable with BPN/3J mice. We conclude that renal nerves contribute to hypertension in BPH mice as RD induced a sustained fall in MAP, which was associated with a reduction of intrarenal renin expression. The lack of inhibition of the depressor effects of pentolinium and enalaprilat by RD suggests that vasoconstrictor effects of the SNS or RAS are not involved.
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Affiliation(s)
- Cindy Gueguen
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Kristy L Jackson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Francine Z Marques
- Heart Failure Research Group, Baker Heart and Diabetes Institute, Melbourne, Australia.,Department of Pharmacology Monash University, Melbourne, Australia
| | - Nina Eikelis
- Human Neurotransmitters Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia.,Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Australia
| | - Sarah Phillips
- Human Neurotransmitters Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia.,Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Australia
| | - Emily R Stevenson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Fadi J Charchar
- Faculty of Science and Technology, Federation University Australia, Ballarat, Victoria, Australia
| | - Gavin W Lambert
- Human Neurotransmitters Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia.,Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Australia
| | - Pamela J Davern
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Geoffrey A Head
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, Australia. .,Department of Pharmacology Monash University, Melbourne, Australia.
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El Sayed K, Macefield VG, Hissen SL, Joyner MJ, Taylor CE. Blood pressure reactivity at onset of mental stress determines sympathetic vascular response in young adults. Physiol Rep 2018; 6:e13944. [PMID: 30552755 PMCID: PMC6294720 DOI: 10.14814/phy2.13944] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 11/22/2018] [Indexed: 11/24/2022] Open
Abstract
We have previously shown in young males that the rate of rise in blood pressure (BP) at the onset of mental stress determines whether or not muscle sympathetic nerve activity (MSNA) has a role in driving the pressor response. The aim of this study was to investigate these interactions in young females. BP and MSNA were recorded continuously in 19 females and 21 males during 2-min mental stressors (mental arithmetic and Stroop test). Physical stressor tasks (cold pressor, handgrip exercise, postexercise ischemia) were also performed. During the first minute of mental arithmetic, the rate of rise in mean arterial pressure (MAP) was significantly greater in negative responders (mean decrease in MSNA) compared with positive responders (mean increase in MSNA) in both males (1.9 ± 0.7 vs. 0.7 ± 0.3 mmHg/sec) and females (1.0 ± 0.3 vs. 0.5 ± 0.2 mmHg/sec). For the Stroop test, there was no significant difference in the rate of the rise in BP between positive and negative responders (P > 0.05). However, peak changes in MAP were significantly greater in negative responders compared with positive responders in both males (22 ± 6 vs. 13 ± 3 mmHg) and females (12 ± 2 vs. 6 ± 1 mmHg). Sympathetic baroreflex sensitivity was greater in negative responders and may contribute to the fall in MSNA experienced by these individuals during mental stress. During physical stressors there were consistent increases in BP and MSNA in males and females. The findings suggest that, in both males and females, BP reactivity at the onset of mental stress dictates whether or not there is an increase or decrease in MSNA.
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Affiliation(s)
- Khadigeh El Sayed
- School of MedicineWestern Sydney UniversitySydneyNew South WalesAustralia
| | - Vaughan G. Macefield
- School of MedicineWestern Sydney UniversitySydneyNew South WalesAustralia
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Baker Heart and Diabetes InstituteMelbourneVictoriaAustralia
| | - Sarah L Hissen
- School of Science and HealthWestern Sydney UniversitySydneyNew South WalesAustralia
| | | | - Chloe E. Taylor
- School of MedicineWestern Sydney UniversitySydneyNew South WalesAustralia
- School of Science and HealthWestern Sydney UniversitySydneyNew South WalesAustralia
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7
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Hissen SL, Sayed KE, Macefield VG, Brown R, Taylor CE. The Stability and Repeatability of Spontaneous Sympathetic Baroreflex Sensitivity in Healthy Young Individuals. Front Neurosci 2018; 12:403. [PMID: 29962929 PMCID: PMC6010576 DOI: 10.3389/fnins.2018.00403] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/25/2018] [Indexed: 01/18/2023] Open
Abstract
Spontaneous sympathetic baroreflex sensitivity (BRS) is a valuable tool for assessing how well the baroreflex buffers beat-to-beat changes in blood pressure. However, there has yet to be a study involving appropriate statistical tests to examine the stability of sympathetic BRS within an experimental session and the repeatability between separate sessions. The aim of this study was to use intra-class correlations, ordinary least products regression, and Bland–Altman analyses to examine the stability and repeatability of spontaneous sympathetic BRS assessment. In addition, the influence of recording duration on values of BRS was assessed. In eighty-four healthy young individuals (49 males, 35 females), continuous measurements of blood pressure, heart rate and muscle sympathetic nerve activity (MSNA) were recorded for 10 min. In a subgroup of 13 participants (11 male, 2 female) the measurements were repeated on a separate day. Sympathetic BRS was quantified using MSNA burst incidence (BRSinc) and total MSNA (BRStotal) for the first 5-min period, the second 5-min period, and a 2-min segment taken from the second 5-min period. Intra-class correlation coefficients indicated moderate stability in sympathetic BRSinc and BRStotal between the first and second 5-min periods in males (BRSincr = 0.63, BRStotalr = 0.78) and females (BRSincr = 0.61, BRStotalr = 0.47) with no proportional bias, but with fixed bias for BRSinc in females. When comparing the first 5-min with the 2-min period (n = 76), the intra-class correlation coefficient indicated poor to moderate repeatability in sympathetic BRSinc and BRStotal for males (BRSincr = -0.01, BRStotalr = 0.70) and females (BRSincr = 0.46, BRStotalr = 0.39). However, Bland–Altman analysis revealed a fixed bias for BRStotal in males and proportional bias for BRStotal in females, with lower BRS values for 5-min recordings. In the subgroup, intra-class correlations indicated moderate repeatability for measures of BRSinc (9 male, 2 female, r = 0.63) and BRStotal (6 male, 2 female, r = 0.68) assessed using 5-min periods recorded on separate days. However, Bland–Altman analysis indicated proportional bias for BRSinc and fixed bias for BRStotal. In conclusion, measures of spontaneous sympathetic BRS are moderately stable and repeatable within and between testing sessions in healthy young adults, provided that the same length of recording is used when making comparisons.
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Affiliation(s)
- Sarah L Hissen
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia
| | - Khadigeh El Sayed
- School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, NSW, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Rachael Brown
- School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Chloe E Taylor
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia.,School of Medicine, Western Sydney University, Sydney, NSW, Australia
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Fudim M, Sobotka AA, Yin YH, Wang JW, Levin H, Esler M, Wang J, Sobotka PA. Selective vs. Global Renal Denervation: a Case for Less Is More. Curr Hypertens Rep 2018; 20:37. [PMID: 29717380 DOI: 10.1007/s11906-018-0838-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Review the renal nerve anatomy and physiology basics and explore the concept of global vs. selective renal denervation (RDN) to uncover some of the fundamental limitations of non-targeted renal nerve ablation and the potential superiority of selective RDN. RECENT FINDINGS Recent trials testing the efficacy of RDN showed mixed results. Initial investigations targeted global RDN as a therapeutic goal. The repeat observation of heterogeneous response to RDN including non-responders with lack of a BP reduction, or even more unsettling, BP elevations after RDN has raised concern for the detrimental effects of unselective global RDN. Subsequent studies have suggested the presence of a heterogeneous fiber population and the potential utility of renal nerve stimulation to identify sympatho-stimulatory fibers or "hot spots." The recognition that RDN can produce heterogeneous afferent sympathetic effects both change therapeutic goals and revitalize the potential of therapeutic RDN to provide significant clinical benefits. Renal nerve stimulation has emerged as potential tool to identify sympatho-stimulatory fibers, avoid sympatho-inhibitory fibers, and thus guide selective RDN.
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Affiliation(s)
- Marat Fudim
- Duke University Medical Center, Durham, NC, USA.,Duke Clinical Research Institute, Durham, NC, USA
| | | | - Yue-Hui Yin
- The 2nd Affiliated Hospital of Chongqing Medical University, Chongqin, China
| | | | | | - Murray Esler
- Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Jie Wang
- Columbia University, New York, NY, USA.,SyMap Medical Ltd., Suzhou, China
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9
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Azadbakht MK, Hassanshahi J, Nematbakhsh M. The Role of Angiotensin II Infusion on the Baroreflex Sensitivity and Renal Function in Intact and Bilateral Renal Denervation Rats. Adv Biomed Res 2018; 7:52. [PMID: 29657937 PMCID: PMC5887788 DOI: 10.4103/abr.abr_192_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Background The role of renin-angiotensin system (RAS) in communication between renal system and cardiovascular system is extremely important. Baroreflex sensitivity (BRS) index defines as heart rate (HR) alteration versus mean arterial pressure (MAP) change ratio . Sympathetic nerve is arm of the baroreflexes and any change in its activity will lead to change in the BRS. The role of angiotensin II (Ang II) infusion in systemic circulation accompanied with bilateral renal denervation (RDN) on BRS index and renal function was studied. Materials and Methods Seventy-two male and female Wistar rats in 12 groups were anesthetized and catheterized. The alteration of MAP and HR responses to phenylephrine infusion compared to control groups was determined in bilateral RDN rats subjected to treat with Ang II (300 or 1000 ng/kg/min) administration. Results The BRS index was elevated in Ang II-treated non-RDN (normal) male rats gradually and dose dependently (P < 0.05), while this index was significantly different when compared with RDN male rats (P < 0.05). Accordingly, the BRS index was significantly lower in RDN than non-RDN male rats, and such observation was not observed in female rats. The creatinine clearance (insignificantly) and urine flow (significantly; P < 0.05) were decreased in both non-RDN and RDN male and female rats treated with Ang II. In RDN model, the serum nitrite levels were decreased in male and increased in female by Ang II infusion when compared with vehicle infusion. Conclusion The Ang II infusion could increase the BRS index in non-RDN (normal) male rats which is significantly greater than BRS index in RDN rats.
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Affiliation(s)
- Mohammad Karim Azadbakht
- Water and Electrolytes Research Center/Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Jalal Hassanshahi
- Water and Electrolytes Research Center/Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mehdi Nematbakhsh
- Water and Electrolytes Research Center/Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran
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10
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Hart EC. Human hypertension, sympathetic activity and the selfish brain. Exp Physiol 2018; 101:1451-1462. [PMID: 27519960 DOI: 10.1113/ep085775] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/10/2016] [Indexed: 12/19/2022]
Abstract
NEW FINDINGS What is the topic of this review? This review article revisits an historical hypothesis that cerebral hypoperfusion, caused by elevated cerebral vascular resistances, causes the onset of high sympathetic nerve activity and hypertension in humans. What advances does it highlight? The review article highlights new evidence indicating that congenital cerebrovascular abnormalities, namely vertebral artery hypoplasia and an incomplete posterior circle of Willis, may play a role in the onset of hypertension. Despite the harmful consequences of high blood pressure (hypertension; e.g. stroke, renal failure, dementia and even death), the underlying physiological mechanisms that cause the onset of hypertension are poorly understood. The most established finding is that hypertension occurs alongside activation of the sympathetic nervous system, yet exactly what triggers this in humans is ambiguous. This review discusses evidence for elevated sympathetic nerve activity, particularly in human hypertension, and revisits an historical theory regarding the aetiology underlying human hypertension that was proposed by Seymour Kety and John Dickinson in the 1940s-1950s. My research group hypothesizes that elevated sympathetic nerve activity and hypertension develop as a fundamental mechanism to maintain adequate cerebral blood flow, which is now termed Cushing's mechanism or the selfish brain hypothesis. Moreover, it goes against the traditional belief that high cerebrovascular resistance is a consequence of hypertension; we propose that this elevated resistance drives hypertension. This review discusses historical and new evidence in animals and humans supporting this hypothesis. In particular, unique human data indicating a higher prevalence of congenital cerebral vascular abnormalities in hypertension are considered.
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Affiliation(s)
- Emma C Hart
- School of Physiology, Pharmacology and Neuroscience, Clinical Research and Imaging Centre, University of Bristol, Bristol, UK
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11
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Lincevicius GS, Shimoura CG, Nishi EE, Oliveira T, Cespedes JG, Bergamaschi CT, Campos RR. Differential effects of renal denervation on arterial baroreceptor function in Goldblatt hypertension model. Auton Neurosci 2017; 208:43-50. [PMID: 28688830 DOI: 10.1016/j.autneu.2017.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 06/09/2017] [Accepted: 06/19/2017] [Indexed: 01/19/2023]
Abstract
Sympathetic vasomotor activity is significantly increased in renovascular hypertension. Renal denervation (DnX) has emerged as a novel therapy for resistant hypertension to drug therapy. However, the underlying mechanisms regarding the reduction in blood pressure (BP) after DnX remain unclear. Thus, the aim of this study was to evaluate the effects of DnX of a clipped kidney on the baseline and baroreceptor reflex control of post-ganglionic sympathetic activity to the contralateral kidney (rSNA) and lumbar (lSNA) nerves in Goldblatt hypertensive rats (2K1C). Renal denervation of an ischaemic kidney (DxX - all visible bundles of nerves were dissected - 10% phenol) was performed 5weeks after clipping (gap width: 0.2mm). Ten days after DnX, BP was significantly reduced (16%) in the 2K1C compared with the undenervated 2K1C (p<0.05). DnX significantly reduced basal rSNA (control group (CT): 110±8, n=14; 2K1C: 150±8, n=12; 2K1C DnX: 89±7, spikes per second (spikes/s); p<0.05, n=8) and lSNA (CT: 137±8, n=8; 2K1C: 202±7, n=11; 2K1C DnX: 131±7, spikes/s; p<0.05, n=8) only in 2K1C rats. DnX significantly improved the arterial baroreceptor sensitivity of rSNA (CT: -2.3±0.2, n=11; 2K1C: -0.7±0.1, n=8; 2K1C DnX: -1.5±0.2, spikes/s/mmHg; p<0.05, n=5) and heart rate for tachycardic response (CT: -3.9±0.5, n=7; 2K1C: -1.9±0.1, n=8; 2K1C DnX: -3.3±0.4, bpm/mmHg; p<0.05, n=8), but not for lSNA in 2K1C rats. The results show that DnX normalized baseline sympathetic vasomotor activity to the lumbar and renal nerves, followed by a differential improvement in the arterial baroreceptor sensitivity. Whether the baroreceptor function sensitivity improvement induced by DnX is a cause or a consequence of BP reduction remains to be determined.
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Affiliation(s)
- Gisele S Lincevicius
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Caroline G Shimoura
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Erika E Nishi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Tales Oliveira
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Juliana G Cespedes
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, Campus São José dos Campos, Brazil
| | - Cássia T Bergamaschi
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil
| | - Ruy R Campos
- Cardiovascular Division, Department of Physiology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Brazil.
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12
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Howden EJ, East C, Lawley JS, Stickford AS, Verhees M, Fu Q, Levine BD. Integrative Blood Pressure Response to Upright Tilt Post Renal Denervation. Am J Hypertens 2017; 30:632-641. [PMID: 28338768 DOI: 10.1093/ajh/hpx018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 02/03/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Whether renal denervation (RDN) in patients with resistant hypertension normalizes blood pressure (BP) regulation in response to routine cardiovascular stimuli such as upright posture is unknown. We conducted an integrative study of BP regulation in patients with resistant hypertension who had received RDN to characterize autonomic circulatory control. METHODS Twelve patients (60 ± 9 [SD] years, n = 10 males) who participated in the Symplicity HTN-3 trial were studied and compared to 2 age-matched normotensive (Norm) and hypertensive (unmedicated, HTN) control groups. BP, heart rate (HR), cardiac output (Qc), muscle sympathetic nerve activity (MSNA), and neurohormonal variables were measured supine, and 30° (5 minutes) and 60° (20 minutes) head-up-tilt (HUT). Total peripheral resistance (TPR) was calculated from mean arterial pressure and Qc. RESULTS Despite treatment with RDN and 4.8 (range, 3-7) antihypertensive medications, the RDN had significantly higher supine systolic BP compared to Norm and HTN (149 ± 15 vs. 118 ± 6, 108 ± 8 mm Hg, P < 0.001). When supine, RDN had higher HR, TPR, MSNA, plasma norepinephrine, and effective arterial elastance compared to Norm. Plasma norepinephrine, Qc, and HR were also higher in the RDN vs. HTN. During HUT, BP remained higher in the RDN, due to increases in Qc, plasma norepinephrine, and aldosterone. CONCLUSION We provide evidence of a possible mechanism by which BP remains elevated post RDN, with the observation of increased Qc and arterial stiffness, as well as plasma norepinephrine and aldosterone levels at approximately 2 years post treatment. These findings may be the consequence of incomplete ablation of sympathetic renal nerves or be related to other factors.
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Affiliation(s)
- Erin J. Howden
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Cara East
- Baylor Soltero Cardiovascular Research Center, Baylor Scott and White Research Institute, Dallas, Texas, USA
| | - Justin S. Lawley
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Abigail S.L. Stickford
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Myrthe Verhees
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Benjamin D. Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, USA
- University of Texas Southwestern Medical Center, Dallas, Texas, USA
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13
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Hoye NA, Wilson LC, Wilkins GT, Jardine DL, Putt TL, Samaranayaka A, Schollum JBW, Walker RJ. Endovascular Renal Denervation in End-Stage Kidney Disease Patients: Cardiovascular Protection-A Proof-of-Concept Study. Kidney Int Rep 2017; 2:856-865. [PMID: 29270493 PMCID: PMC5733679 DOI: 10.1016/j.ekir.2017.04.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 04/17/2017] [Accepted: 04/26/2017] [Indexed: 01/28/2023] Open
Abstract
Introduction Sympathetic neural activation is markedly increased in end-stage kidney disease (ESKD). Catheter-based renal denervation (RDN) reduces sympathetic overactivity and blood pressure in resistant hypertension. We investigated the effect of RDN on sympathetic neural activation and left ventricular mass in patients with ESKD. Methods Nine ESKD (6 hemodialysis and 3 peritoneal dialysis) patients with dialysis vintage of ≥11 months were treated with RDN (EnligHTN system). Data were obtained on a nondialysis day; at baseline, 1, 3, and 12 months post-RDN. Results At baseline sympathetic neural activation measured by muscle sympathetic nervous activity (MSNA) and plasma norepinephrine concentrations were markedly elevated. Left ventricular hypertrophy (LVH) was evident in 8 of the 9 patients. At 12 months post-RDN, blind analysis revealed that MSNAfrequency (–12.2 bursts/min1, 95% CI [–13.6, –10.7]) and LV mass (–27 g/m2, 95% CI [–47, –8]) were reduced. Mean ambulatory BP (systolic: –24 mm Hg, 95% CI [–42, –5] and diastolic: –13 mm Hg, 95% CI [–22, –4]) was also reduced at 12 months. Office BP was reduced as early as 1 month (systolic: –25 mm Hg, 95% CI [–45, –5] and diastolic: –13 mm Hg, 95% CI [–24, –1]). Both ambulatory and office BP had clinically significant reductions in at least 50% of patients out to 12 months. Discussion Catheter-based RDN significantly reduced MSNA and LV mass as well as systemic BP in this group of patients with ESKD.
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Affiliation(s)
- Neil A Hoye
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, Otago, New Zealand.,Department of Renal Medicine, St. James's University Hospital, Leeds, UK
| | - Luke C Wilson
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, Otago, New Zealand
| | - Gerard T Wilkins
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, Otago, New Zealand
| | - David L Jardine
- Department of Medicine, University of Otago, Christchurch, Otago, New Zealand
| | - Tracey L Putt
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, Otago, New Zealand
| | - Ari Samaranayaka
- Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, Dunedin, Otago, New Zealand
| | - John B W Schollum
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, Otago, New Zealand
| | - Robert J Walker
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, Otago, New Zealand
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14
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Burnstock G, Loesch A. Sympathetic innervation of the kidney in health and disease: Emphasis on the role of purinergic cotransmission. Auton Neurosci 2017; 204:4-16. [DOI: 10.1016/j.autneu.2016.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/27/2016] [Accepted: 05/29/2016] [Indexed: 11/29/2022]
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15
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McBryde FD, Hart EC, Ramchandra R, Paton JF. Evaluating the carotid bodies and renal nerves as therapeutic targets for hypertension. Auton Neurosci 2017; 204:126-130. [DOI: 10.1016/j.autneu.2016.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 07/28/2016] [Accepted: 08/01/2016] [Indexed: 11/30/2022]
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16
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Total renal denervation reduces sympathoexcitation to different target organs in a model of chronic kidney disease. Auton Neurosci 2017; 204:81-87. [DOI: 10.1016/j.autneu.2016.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 12/28/2022]
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17
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Nishi EE, Martins BS, Milanez MI, Lopes NR, de Melo JF, Pontes RB, Girardi AC, Campos RR, Bergamaschi CT. Stimulation of renal afferent fibers leads to activation of catecholaminergic and non-catecholaminergic neurons in the medulla oblongata. Auton Neurosci 2017; 204:48-56. [DOI: 10.1016/j.autneu.2017.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 01/17/2017] [Accepted: 01/18/2017] [Indexed: 12/17/2022]
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18
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Wang Y, Dinh TN, Nield A, Krishna SM, Denton K, Golledge J. Renal Denervation Promotes Atherosclerosis in Hypertensive Apolipoprotein E-Deficient Mice Infused with Angiotensin II. Front Physiol 2017; 8:215. [PMID: 28450836 PMCID: PMC5390019 DOI: 10.3389/fphys.2017.00215] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/24/2017] [Indexed: 11/13/2022] Open
Abstract
Objective: To determine the effect of renal denervation (RDN) on the severity of atherosclerosis and aortic aneurysm in hypertensive mice. Methods: Hypertension, atherosclerosis and aortic aneurysm were induced by subcutaneous infusion of angiotensin II (1 μg/kg/min) for 28 days in apolipoprotein E-deficient mice. RDN was conducted using combined surgical and local chemical denervation. The norepinephrine concentration in the kidney was measured by high-performance liquid chromatography. Blood pressure was measured by the tail-cuff method. Atherosclerosis was assessed by Sudan IV staining of the aortic arch. The aortic diameter was measured by the morphometric method. The mRNA expression of genes associated with atherosclerosis and aortic aneurysm were analyzed by quantitative PCR. Results: RDN decreased the median norepinephrine content in the kidney by 93.4% (n = 5-7, P = 0.003) 5 days after the procedure, indicating that the RDN procedure was successful. RDN decreased systolic blood pressure in apolipoprotein E-deficient mice. Mice that had RDN had more severe aortic arch atherosclerosis (median percentage of Sudan IV positive area: 13.2% in control mice, n = 12, and 25.4% in mice having RDN, n = 12, P = 0.028). The severity of the atherosclerosis was negatively correlated with the renal norepinephrine content (spearman r = -0.6557, P = 0.005). RDN did not affect the size of aortic aneurysms formed or the incidence of aortic rupture in mice receiving angiotensin II. RDN significantly increased the aortic mRNA expression of matrix metalloproteinase-2 (MMP-2). Conclusion: RDN promoted atherosclerosis in apolipoprotein E-deficient mice infused with angiotensin II associated with upregulation of MMP-2. The higher MMP-2 expression could be the results of the greater amount of atheroma in the RDN mice. The findings suggest further research is needed to assess potentially deleterious effects of RDN in patients.
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Affiliation(s)
- Yutang Wang
- School of Applied and Biomedical Science, Federation University AustraliaBallarat, VIC, Australia.,The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook UniversityTownsville, QLD, Australia
| | - Tam N Dinh
- School of Applied and Biomedical Science, Federation University AustraliaBallarat, VIC, Australia.,The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook UniversityTownsville, QLD, Australia
| | - Alexander Nield
- School of Applied and Biomedical Science, Federation University AustraliaBallarat, VIC, Australia
| | - Smriti M Krishna
- The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook UniversityTownsville, QLD, Australia
| | - Kate Denton
- Cardiovascular and Renal Physiology, Department of Physiology, Monash UniversityClayton, VIC, Australia
| | - Jonathan Golledge
- The Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, College of Medicine and Dentistry, James Cook UniversityTownsville, QLD, Australia.,Department of Vascular and Endovascular Surgery, The Townsville HospitalTownsville, QLD, Australia
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19
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da Silva Gonçalves Bos D, Happé C, Schalij I, Pijacka W, Paton JFR, Guignabert C, Tu L, Thuillet R, Bogaard HJ, van Rossum AC, Vonk-Noordegraaf A, de Man FS, Handoko ML. Renal Denervation Reduces Pulmonary Vascular Remodeling and Right Ventricular Diastolic Stiffness in Experimental Pulmonary Hypertension. JACC Basic Transl Sci 2017; 2:22-35. [PMID: 29034356 PMCID: PMC5628179 DOI: 10.1016/j.jacbts.2016.09.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 09/17/2016] [Accepted: 09/20/2016] [Indexed: 01/20/2023]
Abstract
Neurohormonal overactivation plays an important role in pulmonary hypertension (PH). In this context, renal denervation, which aims to inhibit the neurohormonal systems, may be a promising adjunct therapy in PH. In this proof-of-concept study, we have demonstrated in 2 experimental models of PH that renal denervation delayed disease progression, reduced pulmonary vascular remodeling, lowered right ventricular afterload, and decreased right ventricular diastolic stiffness, most likely by suppression of the renin-angiotensin-aldosterone system.
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Key Words
- AT1, angiotensin II type 1
- Ea, right ventricular afterload
- Eed, right ventricular stiffness
- Ees, right ventricular contractility
- MCT, monocrotaline model
- PH, pulmonary hypertension
- RAAS, renin angiotensin-aldosterone system
- RD, renal denervation
- SNS, sympathetic nervous system
- SuHx, sugen combined with hypoxia model
- pulmonary hypertension
- renin angiotensin system
- right ventricular failure
- sympathetic nervous system
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Affiliation(s)
- Denielli da Silva Gonçalves Bos
- Department of Pulmonology, VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands.,Department of Physiology VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands
| | - Chris Happé
- Department of Pulmonology, VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands.,Department of Physiology VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands
| | - Ingrid Schalij
- Department of Pulmonology, VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands.,Department of Physiology VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands
| | - Wioletta Pijacka
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Christophe Guignabert
- University of Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre, France.,INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Ly Tu
- University of Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre, France.,INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Raphaël Thuillet
- University of Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin Bicêtre, France.,INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Harm-Jan Bogaard
- Department of Pulmonology, VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands
| | - Albert C van Rossum
- Department of Cardiology, VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands
| | - Anton Vonk-Noordegraaf
- Department of Pulmonology, VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands
| | - Frances S de Man
- Department of Pulmonology, VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands.,Department of Physiology VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands
| | - M Louis Handoko
- Department of Physiology VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands.,Department of Cardiology, VU University Medical Center, Institute for Cardiovascular Research, Amsterdam, the Netherlands
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20
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Narkiewicz K, Ratcliffe LEK, Hart EC, Briant LJB, Chrostowska M, Wolf J, Szyndler A, Hering D, Abdala AP, Manghat N, Burchell AE, Durant C, Lobo MD, Sobotka PA, Patel NK, Leiter JC, Engelman ZJ, Nightingale AK, Paton JFR. Unilateral Carotid Body Resection in Resistant Hypertension: A Safety and Feasibility Trial. ACTA ACUST UNITED AC 2016; 1:313-324. [PMID: 27766316 PMCID: PMC5063532 DOI: 10.1016/j.jacbts.2016.06.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 06/06/2016] [Accepted: 06/07/2016] [Indexed: 11/17/2022]
Abstract
Animal and human data indicate pathological afferent signaling emanating from the carotid body that drives sympathetically mediated elevations in blood pressure in conditions of hypertension. This first-in-man, proof-of-principle study tested the safety and feasibility of unilateral carotid body resection in 15 patients with drug-resistant hypertension. The procedure proved to be safe and feasible. Overall, no change in blood pressure was found. However, 8 patients showed significant reductions in ambulatory blood pressure coinciding with decreases in sympathetic activity. The carotid body may be a novel target for treating an identifiable subpopulation of humans with hypertension.
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Key Words
- ABP, ambulatory blood pressure
- ASBP, ambulatory systolic blood pressure
- BRS, baroreceptor reflex sensitivity
- CB, carotid body
- HRV, heart rate variability
- HVR, hypoxic ventilatory response
- MSNA, muscle sympathetic nerve activity
- OBP, office blood pressure
- OSBP, office systolic blood pressure
- afferent drive
- baroreceptor reflex
- hypertension
- hypoxia
- peripheral chemoreceptor
- sympathetic nervous system
- uCB, unilateral carotid body
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Affiliation(s)
- Krzysztof Narkiewicz
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Laura E K Ratcliffe
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Emma C Hart
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom; School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Linford J B Briant
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Marzena Chrostowska
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Jacek Wolf
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Anna Szyndler
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Dagmara Hering
- Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, Poland
| | - Ana P Abdala
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
| | - Nathan Manghat
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Amy E Burchell
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Claire Durant
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Melvin D Lobo
- NIHR Barts Cardiovascular Biomedical Research Unit, William Harvey Research Institute, QMUL, Charterhouse Square, London, United Kingdom
| | - Paul A Sobotka
- Department of Internal Medicine, Division of Cardiovascular Diseases, The Ohio State University, Columbus, Ohio
| | - Nikunj K Patel
- Neurosurgery, North Bristol NHS Trust, Southmead Hospital, Bristol, United Kingdom
| | - James C Leiter
- Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
| | | | - Angus K Nightingale
- CardioNomics Research Group, Clinical Research & Imaging Centre, University of Bristol and University Hospitals Bristol NHS Foundation Trust, Bristol, United Kingdom
| | - Julian F R Paton
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, United Kingdom
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21
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Fink GD, Phelps JT. Can we predict the blood pressure response to renal denervation? Auton Neurosci 2016; 204:112-118. [PMID: 27530600 DOI: 10.1016/j.autneu.2016.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/08/2016] [Accepted: 07/29/2016] [Indexed: 12/31/2022]
Abstract
Renal denervation (RDN) is a new therapy used to treat drug-resistant hypertension in the clinical setting. Published human trials show substantial inter-individual variability in the blood pressure (BP) response to RDN, even when technical aspects of the treatment are standardized as much as possible between patients. Widespread acceptance of RDN for treating hypertension will require accurate identification of patients likely to respond to RDN with a fall in BP that is clinically significant in magnitude, well-maintained over time and does not cause adverse consequences. In this paper we review and evaluate clinical studies that address possible predictors of the BP response to RDN. We conclude that only one generally reliable predictor has been identified to date, namely pre-RDN BP level, although there is some evidence for a few other factors. Experimental interventions in laboratory animals provide the opportunity to explore potential predictors that are difficult to investigate in human patients. Therefore we also describe results (from our lab and others) with RDN in spontaneously hypertensive rats. Since virtually all patients receiving RDN are taking three or more antihypertensive drugs, a particular focus of our work was on how ongoing antihypertensive drug treatment might alter the BP response to RDN. We conclude that patient age (or duration of hypertension) and concomitant treatment with certain drugs can affect the blood pressure response to RDN and that this information could help predict a favorable clinical response.
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Affiliation(s)
- Gregory D Fink
- Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48840, USA.
| | - Jeremiah T Phelps
- Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48840, USA.
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22
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Sanders MF, Blankestijn PJ. Chronic Kidney Disease As a Potential Indication for Renal Denervation. Front Physiol 2016; 7:220. [PMID: 27375498 PMCID: PMC4896963 DOI: 10.3389/fphys.2016.00220] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 05/26/2016] [Indexed: 01/08/2023] Open
Abstract
Renal denervation is being used as a blood pressure lowering therapy for patients with apparent treatment resistant hypertension. However, this population does not represent a distinct disease condition in which benefit is predictable. In fact, the wide range in effectiveness of renal denervation could be a consequence of this heterogeneous pathogenesis of hypertension. Since renal denervation aims at disrupting sympathetic nerves surrounding the renal arteries, it seems obvious to focus on patients with increased afferent and/or efferent renal sympathetic nerve activity. In this review will be argued, from both a pathophysiological and a clinical point of view, that chronic kidney disease is particularly suited to renal denervation.
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Affiliation(s)
- Margreet F Sanders
- Department of Nephrology and Hypertension, University Medical Centre Utrecht Utrecht, Netherlands
| | - Peter J Blankestijn
- Department of Nephrology and Hypertension, University Medical Centre Utrecht Utrecht, Netherlands
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Salman IM. Current Approaches to Quantifying Tonic and Reflex Autonomic Outflows Controlling Cardiovascular Function in Humans and Experimental Animals. Curr Hypertens Rep 2016; 17:84. [PMID: 26363932 DOI: 10.1007/s11906-015-0597-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of the autonomic nervous system in the pathophysiology of human and experimental models of cardiovascular disease is well established. In the recent years, there have been some rapid developments in the diagnostic approaches used to assess and monitor autonomic functions. Although most of these methods are devoted for research purposes in laboratory animals, many have still found their way to routine clinical practice. To name a few, direct long-term telemetry recording of sympathetic nerve activity (SNA) in rodents, single-unit SNA recording using microneurography in human subjects and spectral analysis of blood pressure and heart rate in both humans and animals have recently received an overwhelming attention. In this article, we therefore provide an overview of the methods and techniques used to assess tonic and reflex autonomic functions in humans and experimental animals, highlighting current advances available and procedure description, limitations and usefulness for diagnostic purposes.
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Affiliation(s)
- Ibrahim M Salman
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia.
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Salman IM. Cardiovascular Autonomic Dysfunction in Chronic Kidney Disease: a Comprehensive Review. Curr Hypertens Rep 2016; 17:59. [PMID: 26071764 DOI: 10.1007/s11906-015-0571-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cardiovascular autonomic dysfunction is a major complication of chronic kidney disease (CKD), likely contributing to the high incidence of cardiovascular mortality in this patient population. In addition to adrenergic overdrive in affected individuals, clinical and experimental evidence now strongly indicates the presence of impaired reflex control of both sympathetic and parasympathetic outflow to the heart and vasculature. Although the principal underlying mechanisms are not completely understood, potential involvements of altered baroreceptor, cardiopulmonary, and chemoreceptor reflex function, along with factors including but not limited to increased renin-angiotensin-aldosterone system activity, activation of the renal afferents and cardiovascular structural remodeling have been suggested. This review therefore analyzes potential mechanisms underpinning autonomic imbalance in CKD, covers results accumulated thus far on cardiovascular autonomic function studies in clinical and experimental renal failure, discusses the role of current interventional and therapeutic strategies in ameliorating autonomic deficits associated with chronic renal dysfunction, and identifies gaps in our knowledge of neural mechanisms driving cardiovascular disease in CKD.
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Affiliation(s)
- Ibrahim M Salman
- The Australian School of Advanced Medicine, Macquarie University, Sydney, New South Wales, Australia,
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25
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Patel HC, Hayward C, Vassiliou V, Patel K, Howard JP, Di Mario C. Renal denervation for the management of resistant hypertension. Integr Blood Press Control 2015; 8:57-69. [PMID: 26672761 PMCID: PMC4675644 DOI: 10.2147/ibpc.s65632] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Renal sympathetic denervation (RSD) as a therapy for patients with resistant hypertension has attracted great interest. The majority of studies in this field have demonstrated impressive reductions in blood pressure (BP). However, these trials were not randomized or sham-controlled and hence, the findings may have been overinflated due to trial biases. SYMPLICITY HTN-3 was the first randomized controlled trial to use a blinded sham-control and ambulatory BP monitoring. A surprise to many was that this study was neutral. Possible reasons for this neutrality include the fact that RSD may not be effective at lowering BP in man, RSD was not performed adequately due to limited operator experience, patients’ adherence with their anti-hypertensive drugs may have changed during the trial period, and perhaps the intervention only works in certain subgroups that are yet to be identified. Future studies seeking to demonstrate efficacy of RSD should be designed as randomized blinded sham-controlled trials. The efficacy of RSD is in doubt, but many feel that its safety has been established through the thousands of patients in whom the procedure has been performed. Over 90% of these data, however, are for the Symplicity™ system and rarely extend beyond 12 months of follow-up. Long-term safety cannot be assumed with RSD and nor should it be assumed that if one catheter system is safe then all are. We hope that in the near future, with the benefit of well-designed clinical trials, the role of renal denervation in the management of hypertension will be established.
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Affiliation(s)
- Hitesh C Patel
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK
| | - Carl Hayward
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK
| | - Vassilis Vassiliou
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK
| | - Ketna Patel
- Department of Cardiology, Royal Free Hospital, London, UK
| | - James P Howard
- National Heart and Lung Institute, Imperial College, London, UK
| | - Carlo Di Mario
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK
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26
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Iliescu R, Lohmeier TE, Tudorancea I, Laffin L, Bakris GL. Renal denervation for the treatment of resistant hypertension: review and clinical perspective. Am J Physiol Renal Physiol 2015. [PMID: 26224718 DOI: 10.1152/ajprenal.00246.2015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
When introduced clinically 6 years ago, renal denervation was thought to be the solution for all patients whose blood pressure could not be controlled by medication. The initial two studies, SYMPLICITY HTN-1 and HTN-2, demonstrated great magnitudes of blood pressure reduction within 6 mo of the procedure and were based on a number of assumptions that may not have been true, including strict adherence to medication and absence of white-coat hypertension. The SYMPLICITY HTN-3 trial controlled for all possible factors believed to influence the outcome, including the addition of a sham arm, and ultimately proved the demise of the initial overly optimistic expectations. This trial yielded a much lower blood pressure reduction compared with the previous SYMPLICITY trials. Since its publication in 2014, there have been many analyses to try and understand what accounted for the differences. Of all the variables examined that could influence blood pressure outcomes, the extent of the denervation procedure was determined to be inadequate. Beyond this, the physiological mechanisms that account for the heterogeneous fall in arterial pressure following renal denervation remain unclear, and experimental studies indicate dependence on more than simply reduced renal sympathetic activity. These and other related issues are discussed in this paper. Our perspective is that renal denervation works if done properly and used in the appropriate patient population. New studies with new approaches and catheters and appropriate controls will be starting later this year to reassess the efficacy and safety of renal denervation in humans.
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Affiliation(s)
- Radu Iliescu
- Department of Physiology, University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania
| | - Thomas E Lohmeier
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Ionut Tudorancea
- Department of Physiology, University of Medicine and Pharmacy, "Gr. T. Popa," Iasi, Romania
| | - Luke Laffin
- Department of Medicine, ASH Comprehensive Hypertension Center, The University of Chicago Medicine, Chicago, Illinois
| | - George L Bakris
- Department of Medicine, ASH Comprehensive Hypertension Center, The University of Chicago Medicine, Chicago, Illinois
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Thaung HPA, Yao Y, Bussey CT, Hughes G, Jones PP, Bahn A, Sammut IA, Lamberts RR. Chronic bilateral renal denervation reduces cardiac hypertrophic remodelling but not β-adrenergic responsiveness in hypertensive type 1 diabetic rats. Exp Physiol 2015; 100:628-39. [DOI: 10.1113/ep085021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/13/2015] [Indexed: 11/08/2022]
Affiliation(s)
- H. P. Aye Thaung
- Department of Physiology - HeartOtago, Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
| | - Yimin Yao
- Department of Pharmacology and Toxicology, Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
| | - Carol T. Bussey
- Department of Physiology - HeartOtago, Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
| | - Gillian Hughes
- Department of Physiology - HeartOtago, Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
| | - Peter P. Jones
- Department of Physiology - HeartOtago, Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
| | - Andrew Bahn
- Department of Physiology - HeartOtago, Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
| | - Ivan A. Sammut
- Department of Pharmacology and Toxicology, Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
| | - Regis R. Lamberts
- Department of Physiology - HeartOtago, Otago School of Medical Sciences; University of Otago; Dunedin New Zealand
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O'Callaghan EL, McBryde FD, Burchell AE, Ratcliffe LEK, Nicolae L, Gillbe I, Carr D, Hart EC, Nightingale AK, Patel NK, Paton JFR. Deep brain stimulation for the treatment of resistant hypertension. Curr Hypertens Rep 2015; 16:493. [PMID: 25236853 DOI: 10.1007/s11906-014-0493-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hypertension is a leading risk factor for the development of several cardiovascular diseases. As the global prevalence of hypertension increases, so too has the recognition of resistant hypertension. Whilst figures vary, the proportion of hypertensive patients that are resistant to multiple drug therapies have been reported to be as high as 16.4 %. Resistant hypertension is typically associated with elevated sympathetic activity and abnormal homeostatic reflex control and is termed neurogenic hypertension because of its presumed central autonomic nervous system origin. This resistance to conventional pharmacological treatment has stimulated a plethora of medical devices to be investigated for use in hypertension, with varying degrees of success. In this review, we discuss a new therapy for drug-resistant hypertension, deep brain stimulation. The utility of deep brain stimulation in resistant hypertension was first discovered in patients with concurrent neuropathic pain, where it lowered blood pressure and improved baroreflex sensitivity. The most promising central target for stimulation is the ventrolateral periaqueductal gray, which has been well characterised in animal studies as a control centre for autonomic outflow. In this review, we will discuss the promise and potential mechanisms of deep brain stimulation in the treatment of severe, resistant hypertension.
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Affiliation(s)
- Erin L O'Callaghan
- School of Physiology & Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
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29
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Barrett CJ. Renal sympathetic nerves - what have they got to do with cardiovascular disease? Exp Physiol 2015; 100:359-65. [DOI: 10.1113/expphysiol.2014.080176] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 01/20/2015] [Indexed: 11/08/2022]
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Poulikakos D, Malik M, Banerjee D. Sex-dependent association between heart rate variability and pulse pressure in haemodialysis patients. Nephron Clin Pract 2014; 128:361-6. [PMID: 25502577 DOI: 10.1159/000368436] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 09/18/2014] [Indexed: 11/19/2022] Open
Abstract
AIMS Increased pulse pressure (PP) is associated with increased cardiovascular mortality in haemodialysis (HD) patients. Autonomic imbalance is common in HD patients and predisposes to sudden cardiac death, but its relationship to PP is unknown. We investigated the relationship between cardiac autonomic modulation assessed by heart rate variability (HRV) and PP in HD patients. METHODS Continuous electrocardiograms recorded during HD sessions were repeated 5 times at 2-week intervals in stable HD patients. The high-frequency (HF) and low-frequency (LF) components and the LF/HF ratio of HRV were calculated during the first and last hour of the recordings. These values and the corresponding systolic blood pressure (SBP), diastolic blood pressure (DBP) and PP measurements were averaged in repeated recordings of each patient. RESULTS Seventy-six patients were included in the final analysis (aged 61 ± 15 years, 32% females, 37% diabetics). In male patients, LF/HF correlated inversely with pre- and post-HD PP (r = -0.369, p = 0.007 and r = -0.546, p = 0.000, respectively), positively with pre- and post-HD DBP (r = 0.358, p = 0.009 and r = 0.306, p = 0.028, respectively) and inversely with post-HD SBP (r = -0.350, p = 0.011). In female patients, LF/HF correlated positively with post-HD SBP (r = 0.422, p = 0.040). CONCLUSION We observed an association between PP and HRV in male HD patients. Sex differences may be important for cardiac risk assessment.
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Lobo MD, de Belder MA, Cleveland T, Collier D, Dasgupta I, Deanfield J, Kapil V, Knight C, Matson M, Moss J, Paton JFR, Poulter N, Simpson I, Williams B, Caulfield MJ. Joint UK societies' 2014 consensus statement on renal denervation for resistant hypertension. Heart 2014; 101:10-6. [PMID: 25431461 PMCID: PMC4283620 DOI: 10.1136/heartjnl-2014-307029] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Resistant hypertension continues to pose a major challenge to clinicians worldwide and has serious implications for patients who are at increased risk of cardiovascular morbidity and mortality with this diagnosis. Pharmacological therapy for resistant hypertension follows guidelines-based regimens although there is surprisingly scant evidence for beneficial outcomes using additional drug treatment after three antihypertensives have failed to achieve target blood pressure. Recently there has been considerable interest in the use of endoluminal renal denervation as an interventional technique to achieve renal nerve ablation and lower blood pressure. Although initial clinical trials of renal denervation in patients with resistant hypertension demonstrated encouraging office blood pressure reduction, a large randomised control trial (Symplicity HTN-3) with a sham-control limb, failed to meet its primary efficacy end point. The trial however was subject to a number of flaws which must be taken into consideration in interpreting the final results. Moreover a substantial body of evidence from non-randomised smaller trials does suggest that renal denervation may have an important role in the management of hypertension and other disease states characterised by overactivation of the sympathetic nervous system. The Joint UK Societies does not recommend the use of renal denervation for treatment of resistant hypertension in routine clinical practice but remains committed to supporting research activity in this field. A number of research strategies are identified and much that can be improved upon to ensure better design and conduct of future randomised studies.
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Affiliation(s)
- Melvin D Lobo
- On behalf of the British Hypertension Society Barts NIHR Cardiovascular Biomedical Research Unit, William Harvey Research Institute, Queen Mary University of London, London, UK Department of Cardiovascular Medicine, Barts Health NHS Trust, London, UK
| | - Mark A de Belder
- The British Cardiovascular Society The British Cardiovascular Intervention Society Cardiothoracic Division, The James Cook University Hospital, Middlesbrough, UK
| | - Trevor Cleveland
- The British Society for Interventional Radiology Sheffield Vascular Institute, Sheffield Teaching Hospitals NHSFT, Northern General Hospital, Sheffield, UK
| | - David Collier
- On behalf of the British Hypertension Society Barts NIHR Cardiovascular Biomedical Research Unit, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Indranil Dasgupta
- The Renal Association Department of Renal Medicine, Birmingham Heartlands Hospital, Birmingham, UK
| | - John Deanfield
- Cardiothoracic Division, The James Cook University Hospital, Middlesbrough, UK The National Institute for Cardiovascular Outcomes Research, University College London, London, UK
| | - Vikas Kapil
- On behalf of the British Hypertension Society Barts NIHR Cardiovascular Biomedical Research Unit, William Harvey Research Institute, Queen Mary University of London, London, UK Department of Cardiovascular Medicine, Barts Health NHS Trust, London, UK
| | - Charles Knight
- Department of Cardiovascular Medicine, Barts Health NHS Trust, London, UK The British Cardiovascular Society
| | - Matthew Matson
- The British Society for Interventional Radiology Barts NIHR Cardiovascular Biomedical Research Unit, William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Jonathan Moss
- The British Society for Interventional Radiology Interventional Radiology Unit, Gartnavel General Hospital, Glasgow, UK
| | - Julian F R Paton
- On behalf of the British Hypertension Society School of Physiology & Pharmacology, Bristol Cardiovascular Medical Sciences Building, University of Bristol, Bristol, UK
| | - Neil Poulter
- On behalf of the British Hypertension Society International Centre for Circulatory Health, Imperial College, London, UK
| | - Iain Simpson
- The British Cardiovascular Society Wessex Regional Cardiac Unit, University Hospital Southampton, UK
| | - Bryan Williams
- On behalf of the British Hypertension Society Institute of Cardiovascular Sciences, University College London, London, UK
| | - Mark J Caulfield
- On behalf of the British Hypertension Society Barts NIHR Cardiovascular Biomedical Research Unit, William Harvey Research Institute, Queen Mary University of London, London, UK Department of Cardiovascular Medicine, Barts Health NHS Trust, London, UK
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Phillips JK. What underlies the prolonged hypotensive effect of catheter-based renal denervation in humans? Hypertension 2014; 65:276-7. [PMID: 25403605 DOI: 10.1161/hypertensionaha.114.04346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Wang Y. Ethnicity and sympathetic tone: predictors of the blood pressure response to renal denervation? Nat Rev Cardiol 2014; 11:638. [DOI: 10.1038/nrcardio.2014.70-c1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ratcliffe LEK, Pijacka W, McBryde FD, Abdala AP, Moraes DJ, Sobotka PA, Hart EC, Narkiewicz K, Nightingale AK, Paton JFR. Rebuttal from L. E. K. Ratcliffe, W. Pijacka, F. D. McBryde, A. P. Abdala, D. J. Moraes, P. A. Sobotka, E. C. Hart, K. Narkiewicz, A. K. Nightingale and J. F. R. Paton. J Physiol 2014; 592:3949-50. [PMID: 25225256 DOI: 10.1113/jphysiol.2014.279737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- L E K Ratcliffe
- CardioNomics Research Group, Clinical Research and Imaging Centre and School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
| | - W Pijacka
- CardioNomics Research Group, Clinical Research and Imaging Centre and School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
| | - F D McBryde
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - A P Abdala
- CardioNomics Research Group, Clinical Research and Imaging Centre and School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
| | - D J Moraes
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, 14049-900, SP, Brazil
| | - P A Sobotka
- The Ohio State University, 2015 Marywood Lane West, St Paul, MN, 55118, USA
| | - E C Hart
- CardioNomics Research Group, Clinical Research and Imaging Centre and School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
| | - K Narkiewicz
- Department of Hypertension and Diabetology, Medical University of Gdansk, Debinki 7c, 80-952 Gdansk, Poland
| | - A K Nightingale
- CardioNomics Research Group, Clinical Research and Imaging Centre and School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
| | - J F R Paton
- CardioNomics Research Group, Clinical Research and Imaging Centre and School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
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35
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Wang Y. Letter by Wang regarding article, "renal denervation for the treatment of cardiovascular high risk-hypertension or beyond?". Circ Res 2014; 115:e18. [PMID: 25214577 DOI: 10.1161/circresaha.114.304917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yutang Wang
- School of Health Sciences, Federation University Australia, Mount Helen, Victoria, Australia
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36
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37
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Ivy JR, Bailey MA. Pressure natriuresis and the renal control of arterial blood pressure. J Physiol 2014; 592:3955-67. [PMID: 25107929 DOI: 10.1113/jphysiol.2014.271676] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The regulation of extracellular fluid volume by renal sodium excretion lies at the centre of blood pressure homeostasis. Renal perfusion pressure can directly regulate sodium reabsorption in the proximal tubule. This acute pressure natriuresis response is a uniquely powerful means of stabilizing long-term blood pressure around a set point. By logical extension, deviation from the set point can only be sustained if the pressure natriuresis mechanism is impaired, suggesting that hypertension is caused or sustained by a defect in the relationship between renal perfusion pressure and sodium excretion. Here we describe the role of pressure natriuresis in blood pressure control and outline the cascade of biophysical and paracrine events in the renal medulla that integrate the vascular and tubular response to altered perfusion pressure. Pressure natriuresis is impaired in hypertension and mechanistic insight into dysfunction comes from genetic analysis of blood pressure disorders. Transplantation studies in rats show that blood pressure is determined by the genotype of the kidney and Mendelian hypertension indicates that the distal nephron influences the overall natriuretic efficiency. These approaches and the outcomes of genome-wide-association studies broaden our view of blood pressure control, suggesting that renal sympathetic nerve activity and local inflammation can impair pressure natriuresis to cause hypertension. Understanding how these systems interact is necessary to tackle the global burden of hypertension.
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Affiliation(s)
- Jessica R Ivy
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Matthew A Bailey
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
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Zuern CS, Eick C, Rizas KD, Bauer S, Langer H, Gawaz M, Bauer A. Reply: Baroreflex sensitivity: a reliable predictor of response to renal denervation? J Am Coll Cardiol 2014; 64:233-4. [PMID: 24509282 DOI: 10.1016/j.jacc.2013.11.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 11/26/2013] [Indexed: 11/18/2022]
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39
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Hering D, Esler MD, Schlaich MP. Baroreflex sensitivity: a reliable predictor of response to renal denervation? J Am Coll Cardiol 2014; 64:232-3. [PMID: 24509281 DOI: 10.1016/j.jacc.2013.10.088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 10/10/2013] [Indexed: 11/27/2022]
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40
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Maliha G, Townsend RR. An Update on Treatment Options for Drug Resistant Hypertension. CURRENT CARDIOVASCULAR RISK REPORTS 2014. [DOI: 10.1007/s12170-014-0394-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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41
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Renal Denervation for Drug-Resistant Hypertension: Suffering Its Original Sin, Seeking Redemption. Can J Cardiol 2014; 30:476-8. [DOI: 10.1016/j.cjca.2014.02.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 02/15/2014] [Indexed: 12/16/2022] Open
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Angle JF, Prince EA, Matsumoto AH, Lohmeier TE, Roberts AM, Misra S, Razavi MK, Katholi RE, Sarin SN, Sica DA, Shivkumar K, Ahrar K. Proceedings from the Society of Interventional Radiology Foundation Research Consensus Panel on Renal Sympathetic Denervation. J Vasc Interv Radiol 2014; 25:497-509. [PMID: 24674208 DOI: 10.1016/j.jvir.2013.12.572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 12/27/2013] [Accepted: 12/27/2013] [Indexed: 10/25/2022] Open
Affiliation(s)
- John F Angle
- Department of Radiology, Division of Vascular and Interventional Radiology, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22908.
| | - Ethan A Prince
- Department of Radiology, Division of Vascular and Interventional Radiology, Brown University, Providence, Rhode Island
| | - Alan H Matsumoto
- Department of Radiology, Division of Vascular and Interventional Radiology, University of Virginia Health System, 1215 Lee Street, Charlottesville, VA 22908
| | - Thomas E Lohmeier
- Department of Physiology, University of Mississippi, Jackson, Mississippi
| | - Andrew M Roberts
- Department of Physiology, University of Louisville, Louisville, Kentucky
| | - Sanjay Misra
- Department of Radiology, Division of Vascular and Interventional Radiology, Mayo Clinic, Rochester, Minnesota
| | - Mahmood K Razavi
- Vascular & Interventional Specialists of Orange County, Inc., Los Angeles, California
| | - Richard E Katholi
- Department of Cardiology, Prairie Heart Institute at St. John's Hospital, Springfield, Illinois
| | - Shawn N Sarin
- Department of Radiology, Division of Vascular and Interventional Radiology, George Washington University, Washington, D.C
| | - Domenic A Sica
- Department of Internal Medicine, Division of Nephrology, Virginia Commonwealth University, Richmond, Virginia
| | - Kalyanam Shivkumar
- Department of Internal Medicine, Division of Cardiology, University of California, Los Angeles, Los Angeles, California
| | - Kamran Ahrar
- Department of Radiology, Division of Vascular and Interventional Radiology, University of Texas, MD Anderson Cancer Center, Houston, Texas
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43
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Kapil V, Jain AK, Lobo MD. Renal Sympathetic Denervation - A Review of Applications in Current Practice. Interv Cardiol 2014; 9:54-61. [PMID: 29588780 PMCID: PMC5808654 DOI: 10.15420/icr.2011.9.1.54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/18/2014] [Indexed: 02/07/2023] Open
Abstract
Resistant hypertension is associated with high morbidity and mortality despite numerous pharmacological strategies. A wealth of preclinical and clinical data have demonstrated that resistant hypertension is associated with elevated renal and central sympathetic tone. The development of interventional therapies to modulate the sympathetic nervous system potentially represents a paradigm shift in the strategy for blood pressure control in this subset of patients. Initial first-in-man and pivotal, randomised controlled trials of endovascular, radio-frequency renal sympathetic denervation have spawned numerous iterations of similar technology, as well as many novel concepts for achieving effective renal sympatholysis. This review details the current knowledge of these devices and the evidence base behind each technology.
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Affiliation(s)
- Vikas Kapil
- William Harvey Heart Centre, NIHR Cardiovascular Biomedical Research Unit, Centre for Clinical Pharmacology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Barts Hypertension Clinic, Department of Clinical Pharmacology, Barts Health NHS Trust, London, UK
| | - Ajay K Jain
- William Harvey Heart Centre, NIHR Cardiovascular Biomedical Research Unit, Centre for Clinical Pharmacology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Department of Cardiology, London Chest Hospital, Barts Health NHS Trust, London, UK
| | - Melvin D Lobo
- William Harvey Heart Centre, NIHR Cardiovascular Biomedical Research Unit, Centre for Clinical Pharmacology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
- Barts Hypertension Clinic, Department of Clinical Pharmacology, Barts Health NHS Trust, London, UK
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It is urgent to investigate predictors of the response of blood pressure to renal denervation. Can J Cardiol 2014; 30:465.e7. [PMID: 24561011 DOI: 10.1016/j.cjca.2013.12.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 12/16/2013] [Indexed: 11/23/2022] Open
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Hoye NA, Baldi JC, Putt TL, Schollum JB, Wilkins GT, Walker RJ. Endovascular renal denervation: a novel sympatholytic with relevance to chronic kidney disease. Clin Kidney J 2014; 7:3-10. [PMID: 25859344 PMCID: PMC4389153 DOI: 10.1093/ckj/sft130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 10/01/2013] [Indexed: 01/20/2023] Open
Abstract
Endovascular renal denervation (sympathectomy) is a novel procedure developed for the treatment of resistant hypertension. Evidence suggests that it reduces both afferent and efferent sympathetic nerve activity, which may offer clinical benefit over and above any blood pressure-lowering effect. Studies have shown objective improvements in left ventricular mass, ventricular function, central arterial stiffness, central haemodynamics, baroreflex sensitivity and arrhythmia frequency. Benefits have also been seen in insulin resistance, microalbuminuria and glomerular filtration rate. In chronic kidney disease, elevated sympathetic activity has been causally linked to disease progression and cardiovascular sequelae. Effecting a marked reduction in sympathetic hyperactivity may herald a significant step in the management of this and other conditions. In this in-depth review, the pathophysiology and clinical significance of the sympatholytic effects of endovascular renal denervation are discussed.
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Affiliation(s)
- Neil A Hoye
- Department of Medicine , Dunedin School of Medicine , Dunedin , New Zealand
| | - James C Baldi
- Department of Medicine , Dunedin School of Medicine , Dunedin , New Zealand
| | - Tracey L Putt
- Department of Medicine , Dunedin School of Medicine , Dunedin , New Zealand
| | - John B Schollum
- Department of Medicine , Dunedin School of Medicine , Dunedin , New Zealand
| | - Gerard T Wilkins
- Department of Medicine , Dunedin School of Medicine , Dunedin , New Zealand
| | - Robert J Walker
- Department of Medicine , Dunedin School of Medicine , Dunedin , New Zealand
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Abstract
Renal denervation is increasingly being adopted as a treatment option in patients with resistant hypertension. The long-term safety of this procedure is unknown. Though the procedure interrupts the sympathetic nerves at the renal level, it also has effects on other organ beds, notably the heart and vasculature. These effects have been purported to be clinically beneficial and thus formed a rationale for examining the role of renal denervation in other conditions, including heart failure, arrhythmia, obstructive sleep apnoea and the metabolic syndrome. There is a theoretical concern that attenuating the renal sympathetic nerves might cause orthostatic hypotension or syncope. From the limited data available from hypertension trials, the procedure has not been associated with excessive episodes of syncope and this is supported by mechanistic tilt table data in asymptomatic patients. Ultimately, the safety of this technique will only be established once we have larger phase III/IV studies.
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Abstract
Orthostatic hypertension-a condition characterized by a hyperactive pressor response to orthostatic stress-is an emerging risk factor for cardiovascular disease and is associated with hypertensive target-organ damage (resulting in silent cerebrovascular disease, left ventricular hypertrophy, carotid atherosclerosis and/or chronic kidney disease) and cardiovascular events (such as coronary artery disease and lacunar stroke). The condition is also considered to be a form of prehypertension as it precedes hypertension in young, normotensive adults. Orthostatic blood pressure changes can be assessed using orthostatic stress tests, including clinic active standing tests, home blood pressure monitoring and the head-up tilting test. Devices for home and for ambulatory blood pressure monitoring that are equipped with position sensors and do not induce a white-coat effect have increased the sensitivity and specificity of diagnosis of out-of-clinic orthostatic hypertension. Potential major mechanisms of orthostatic hypertension are sympathetic hyperactivity (as a result of hypersensitivity of the cardiopulmonary and arterial baroreceptor reflex) and α-adrenergic hyperactivation. Orthostatic hypertension is also associated with morning blood pressure surge and extreme nocturnal blood pressure dipping, both of which increase the pulsatile haemodynamic stress of central arterial pressure and blood flow in patients with systemic haemodynamic atherothrombotic syndrome.
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Hirooka Y, Kishi T, Ito K, Sunagawa K. Potential clinical application of recently discovered brain mechanisms involved in hypertension. Hypertension 2013; 62:995-1002. [PMID: 24101665 DOI: 10.1161/hypertensionaha.113.00801] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Yoshitaka Hirooka
- Department of Advanced Cardiovascular Regulation and Therapeutics, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
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