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Neuroadrenergic function in type 2 diabetic (T2D) patients without neuropathy is poorly characterized. We therefore compared sympathetic nervous system activity at rest and during an oral glucose tolerance test in obese metabolic syndrome (MetS) subjects classified as glucose intolerant (impaired glucose tolerance [IGT]; n = 17) or treatment-naive T2D (n = 17). Untreated subjects, matched for age (mean 59 ± 1 year), sex, BMI (32.4 ± 0.6 kg/m(2)), and family history of diabetes were studied. We measured resting muscle sympathetic nerve activity (MSNA) by microneurography, whole-body norepinephrine kinetics by isotope dilution, insulin sensitivity by euglycemic-hyperinsulinemic clamp (steady-state glucose utilization adjusted for fat-free mass and steady-state insulin concentration [M/I]), and MetS components. T2D subjects had higher resting MSNA burst incidence (67 ± 4 versus 55 ± 3 bursts per 100 heartbeats; P = 0.05) and arterial norepinephrine levels (264 ± 33 versus 167 ± 16 pg/mL; P = 0.02), lower plasma norepinephrine clearance (by 17%; P = 0.03), and reduced neuronal reuptake compared with IGT subjects (by 46%; P = 0.04). Moreover, norepinephrine spillover responses to glucose ingestion were blunted in T2D subjects. The M/I value independently predicted whole-body norepinephrine spillover (r = -0.47; P = 0.008), whereas fasting insulin level related to neuronal norepinephrine reuptake (r = -0.35, P = 0.047). These findings demonstrate that progression to T2D is associated with increased central sympathetic drive, blunted sympathetic responsiveness, and altered norepinephrine disposition. [ABSTRACT FROM AUTHOR]

Multiple sham-controlled clinical trials have demonstrated significant reductions in both office and 24-h blood pressure (BP) following radiofrequency renal denervation (RDN) in the uncontrolled hypertension population. Notably, the blood pressure response varies widely within individual participants, thus showing a clinical need to identify potential RDN "responders" prior to the procedure. Despite multiple analytic efforts, no single parameter, aside from baseline blood pressure, has been consistently associated with BP reduction following RDN. However, this failure may be due to limitations in empiric definitions of responders. Indeed, commonly applied responder definitions based on the difference between two point-in-time BP measurements are fraught due to visit-to-visit variability in office and 24-h blood pressure endpoints. Several factors should be considered to develop a more clinically useful operational definition of procedural response including relative changes in office and 24-h BP, consideration of the temporal response to RDN, as well as adjustment for baseline BP. The current evidence may provide incentives for future expert consensus to precisely define responders to hypertension treatments., Competing Interests: Compliance with ethical standards Conflict of interest RES reports grants and personal fees from Medtronic, Recor, and Ablative Solutions. DAH is a full-time employee of Medtronic, Inc. MB reports support from Astra-Zeneca, Bayer, BMS, Boehringer-Ingelheim, Glaxo, Medtronic, Novartis, ReCor, Servier and Vifor. MB is funded by the German Research Foundation (DFG, TTR 219, S-01, M-03, project number 322900939). DEK receives institutional research/grant support from Biotronik, Boston Scientific,. Orbus Neich, Teleflex, Medtronic, and Ablative Solutions; he also receives personal consulting honoraria from Medtronic and HyperQure. KK receives personal fees from Medtronic, receives grants from A&D Company, JIMRO, OmronHealthcare, CureApp, Terumo, and Fukuda Denshi, receives honoraria from Otsuka Pharmaceuticals and Omron Healthcare, and participates on the advisory board of Fukuda Denshi. FM is supported by Deutsche Gesellschaft für Kardiologie (DGK), Deutsche Forschungsgemeinschaft (SFB TRR219, Project-ID 322900939), and Deutsche Herzstiftung. Saarland University has received scientific support from Ablative Solutions, Medtronic and ReCor Medical. Until May 2024, FM has received speaker honoraria/consulting fees from Ablative Solutions, Amgen, Astra-Zeneca, Bayer, Boehringer Ingelheim, Inari, Medtronic, Merck, ReCor Medical, Servier, and Terumo. KT receives payments from Medtronic for work as centre principal investigator. MAW is a consultant for Medtronic, ReCor Medical, Ablative Solutions, Johnson & Johnson, and Urovant. MDE has received consulting fees and travel and research support from Medtronic. RET is a consultant for Medtronic, Axio, Regeneron, Bard, OBIO and AstraZeneca. Royalties from UpToDate., (© 2024. The Author(s).)

Background: Renal denervation is a recognized adjunct therapy for hypertension with clinically significant blood pressure (BP)-lowering effects. Long-term follow-up data are critical to ascertain durability of the effect and safety. Aside from the 36-month follow-up data available from randomized control trials, recent cohort analyses extended follow-up out to 10 years. We sought to analyze study-level data and quantify the ambulatory BP reduction of renal denervation across contemporary randomized sham-controlled trials and available long-term follow-up data up to 10 years from observational studies., Methods: A systematic review was performed with data from 4 observational studies with follow-up out to 10 years and 2 randomized controlled trials meeting search and inclusion criteria with follow-up data out to 36 months. Study-level data were extracted and compared statistically., Results: In 2 contemporary randomized controlled trials with 36-month follow-up, an average sham-adjusted ambulatory systolic BP reduction of -12.7±4.5 mm Hg from baseline was observed ( P =0.05). Likewise, a -14.8±3.4 mm Hg ambulatory systolic BP reduction was found across observational studies with a mean long-term follow-up of 7.7±2.8 years (range, 3.5-9.4 years; P =0.0051). The observed reduction in estimated glomerular filtration rate across the long-term follow-up was in line with the predicted age-related decline. Antihypertensive drug burden was similar at baseline and follow-up., Conclusions: Renal denervation is associated with a significant and clinically meaningful reduction in ambulatory systolic BP in both contemporary randomized sham-controlled trials up to 36 months and observational cohort studies up to 10 years without adverse consequences on renal function., Competing Interests: Disclosures M.P. Schlaich has received support from a National Health and Medical Research Council Research Fellowship and research support from Medtronic, Abbott, and Servier Australia. He serves on scientific advisory boards for Abbott, Boehringer Ingelheim, Servier, Novartis, and Medtronic. A. Walton is a Proctor for Medtronic and Abbott, is on the Medical Advisory Board of Medtronic, and receives grant support from Medtronic, Abbott, and Edwards. M.D. Esler and G.W. Lambert have received consulting fees and travel and research support from Medtronic. The other authors report no conflicts.

The importance of the sympathetic nervous system in essential hypertension has been recognized in 2 eras. The first was in early decades of the 20 th century, through to the 1960s. Here, the sympathetic nervous system was identified as a target for the treatment of hypertension, and an extensive range of antiadrenergic therapies were developed. Then, after a period of lapsed interest, in a second era from 1985 on, the development of precise measures of human sympathetic nerve firing and transmitter release allowed demonstration of the importance of neural mechanisms in the initiation and maintenance of the arterial blood pressure elevation in hypertension. This led to the development of a device treatment of hypertension, catheter-based renal denervation, which we will discuss., Competing Interests: Disclosures M.D. Esler and J.W. Osborn have received consulting fees and travel and research support from Medtronic. M.P. Schlaich has received research support from Medtronic, Abbott, and Servier Australia. He serves on scientific advisory boards for Abbott, BI, Servier, Novartis, and Medtronic.

Background: Renal denervation (RDN) has been consistently shown in recent sham-controlled clinical trials to reduce blood pressure (BP). Salt sensitivity is a critical factor in hypertension pathogenesis, but cumbersome to assess by gold-standard methodology. Twenty-four-hour average heart rate (HR) and mean arterial pressure (MAP) dipping, taken by ambulatory blood pressure monitoring (ABPM), stratifies patients into high, moderate, and low salt sensitivity index (SSI) risk categories., Objectives: We aimed to assess whether ABPM-derived SSI risk could predict the systolic blood pressure reduction at long-term follow-up in a real-world RDN patient cohort., Methods: Sixty participants had repeat ABPM as part of a renal denervation long-term follow-up. Average time since RDN was 8.9 ± 1.2 years. Based on baseline ABPM, participants were stratified into low (HR < 70 bpm and MAP dipping > 10%), moderate (HR ≥70 bpm or MAP dipping ≤ 10%), and high (HR ≥ 70 bpm and MAP dipping ≤ 10%) SSI risk groups, respectively., Results: One-way ANOVA indicated a significant treatment effect ( P  = 0.03) between low ( n  = 15), moderate ( n  = 35), and high ( n  = 10) SSI risk with systolic BP reduction of 9.6 ± 3.7 mmHg, 8.4 ± 3.5 mmHg, and 28.2 ± 9.6 mmHg, respectively. Baseline BP was not significantly different between SSI Risk groups ( P  = 0.18). High SSI risk independently correlated with systolic BP reduction ( P  = 0.02)., Conclusions: Our investigation indicates that SSI risk may be a simple and accessible measure for predicting the BP response to RDN. However, the influence of pharmacological therapy on these participants is an important extraneous variable requiring testing in prospective or drug naive RDN cohorts., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Aims: Catheter-based radiofrequency renal denervation (RF RDN) has recently been approved for clinical use in the European Society of Hypertension guidelines and by the US FDA. This study evaluated the lifetime cost-effectiveness of RF RDN using contemporary evidence., Methods and Results: A decision-analytic model based on multivariate risk equations projected clinical events, quality-adjusted life years (QALYs) and costs. The model consisted of seven health states: hypertension alone, myocardial infarction (MI), other symptomatic coronary artery disease, stroke, heart failure (HF), end-stage renal disease, and death. Risk reduction associated with changes in office systolic blood pressure (oSBP) was estimated based on a published meta-regression of hypertension trials. The base case effect size of -4.9 mmHg oSBP (observed vs. sham control) was taken from the SPYRAL HTN-ON MED trial of 337 patients. Costs were based on NHS England data. The incremental cost-effectiveness ratio (ICER) was evaluated against the NICE cost-effectiveness threshold of £20 000-30 000 per QALY gained. Extensive scenario and sensitivity analyses were conducted, including the ON-MED subgroup on three medications and pooled effect sizes. RF RDN resulted in a relative risk reduction in clinical events over 10 years (0.80 for stroke, 0.88 for MI, 0.72 for HF), with an increase in health benefit over a patient's lifetime, adding 0.35 QALYs at a cost of £4 763, giving an ICER of £13 482 per QALY gained. Findings were robust across tested scenarios., Conclusion: Catheter-based radiofrequency RDN can be a cost-effective strategy for uncontrolled hypertension in the UK, with an ICER substantially below the NICE cost-effectiveness threshold. Funding: Medtronic Inc., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: Recent sham-controlled randomized clinical trials have confirmed the safety and efficacy of catheter-based renal denervation (RDN). Long-term safety and efficacy data beyond 3 years are scarce. Here, we report on outcomes after RDN in a cohort of patients with resistant hypertension with an average of ≈9-year follow-up (FU)., Methods: We recruited patients with resistant hypertension who were previously enrolled in various RDN trials applying radiofrequency energy for blood pressure (BP) lowering. All participants had baseline assessments before RDN and repeat assessment at long-term FU including medical history, automated office and ambulatory BP measurement, and routine blood and urine tests. We analyzed changes between baseline and long-term FU., Results: A total of 66 participants (mean±SD, 70.0±10.3 years; 76.3% men) completed long-term FU investigations with a mean of 8.8±1.2 years post-procedure. Compared with baseline, ambulatory systolic BP was reduced by -12.1±21.6 (from 145.2 to 133.1) mm Hg ( P <0.0001) and diastolic BP by -8.8±12.8 (from 81.2 to 72.7) mm Hg ( P <0.0001). Mean heart rate remained unchanged. At long-term FU, participants were on one less antihypertensive medication compared with baseline ( P =0.0052). Renal function assessed by estimated glomerular filtration rate fell within the expected age-associated rate of decline from 71.1 to 61.2 mL/min per 1.73 m 2 . Time above target was reduced significantly from 75.0±25.9% at baseline to 47.3±30.3% at long-term FU ( P <0.0001)., Conclusions: RDN results in a significant and robust reduction in both office and ambulatory systolic and diastolic BP at ≈9-year FU after catheter-based RDN on less medication and without evidence of adverse consequences on renal function.

Background: Renal denervation (RDN) has been proven in multiple sham-controlled trials to lower blood pressure (BP) in various forms of hypertension. RDN-mediated interruption of sympathetic signaling through its effects on renal blood flow, salt retention, and renin release are likely contributors to the BP-lowering effects. However, the impact of RDN on salt sensitivity in humans has not yet been explored., Methods: We, therefore, investigated the effect of RDN on ambulatory BP monitoring-derived salt sensitivity in a cohort of patients with uncontrolled hypertension on habitual salt intake. RDN was performed in 153 hypertensive patients, who were categorized into low intermediate and high-salt sensitivity groups, based on the ambulatory BP monitoring-derived salt sensitivity index estimated prior to (baseline) and at 3, 6 and 12 months after the procedure as previously described. Crude and adjusted mixed effects ordinal regression models were fitted to test for changes in the proportions of salt sensitivity risk during follow-up., Results: The proportions of individuals in the intermediate and high-salt sensitivity risk group increased after RDN and the odds for being in a higher estimated salt sensitivity risk group at 3, 6 and 12 months follow-up compared with baseline were highly significant during the 12 months follow-up period., Conclusion: Increased salt sensitivity after RDN may represent a compensatory mechanism to maintain renal capacity for adequate salt handling. This novel finding may have implications for patient management after RDN, such as prescription of salt moderation to further optimize RDN-induced BP-lowering efficacy., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Sympathetic overdrive plays a key role in the perturbation of cardiometabolic homeostasis. Diet-induced and exercise-induced weight loss remains a key strategy to combat metabolic disorders, but is often difficult to achieve. Current pharmacological approaches result in variable responses in different patient cohorts and long-term efficacy may be limited by medication intolerance and nonadherence. A clinical need exists for complementary therapies to curb the burden of cardiometabolic diseases. One such approach may include interventional sympathetic neuromodulation of organs relevant to cardiometabolic control. The experience from catheter-based renal denervation studies clearly demonstrates the feasibility, safety and efficacy of such an approach. In analogy, denervation of the common hepatic artery is now feasible in humans and may prove to be similarly useful in modulating sympathetic overdrive directed towards the liver, pancreas and duodenum. Such a targeted multiorgan neuromodulation strategy may beneficially influence multiple aspects of the cardiometabolic disease continuum offering a holistic approach., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Unlike noradrenaline, the sympathetic neurotransmitter which overflows to the circulation, adrenaline (ADR) is a secreted hormone, with a low plasma concentration, and plasma concentration for biological action a log order lower than that of noradrenaline. The venous drainage of the left adrenal medulla into the left renal vein does expose this vein to uniquely high plasma ADR concentrations and possible risk of thrombosis at high rates of ADR secretion. There is typically a different timeframe for adrenal medullary and sympathetic nervous system responses: ADR release is short term in contrast with sympathetic activation persisting for years in heart failure and hypertension. The historic view of Walter Cannon, subject to recent review, that the sympathoadrenal system is a unified biological system, was deconstructed further with demonstration of frequent mismatching of adrenal medullary and sympathetic nervous responses. Under gravity stimulation with standing, there is prompt sympathetic activation without ADR release. In many diseases, notably obesity, hypertension, heart failure and depressive illness, an activated sympathetic nervous system and silent adrenal medulla coexist. The therapeutic corollary of this is that ADR blockade is much less commonly needed clinically than pharmacological antagonism of the sympathetic nervous system., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Amongst other immune cells, neutrophils play a key role in systemic inflammation leading to cardiovascular disease and can release inflammatory factors, including lipocalin-2 (LCN2). LCN2 drives cardiac hypertrophy and plays a role in maladaptive remodelling of the heart and has been associated with renal injury. While lifestyle factors such as diet and exercise are known to attenuate low-grade inflammation, their ability to modulate plasma LCN2 levels is unknown. Forty-eight endurance athletes and 52 controls (18-55 years) underwent measurement for various cardiovascular health indicators, along with plasma LCN2 concentration. No significant difference in LCN2 concentration was seen between the two groups. LCN2 was a very weak predictor or absent from models describing blood pressures or predicting athlete status. In another cohort, 57 non-diabetic overweight or obese men and post-menopausal women who fulfilled Adult Treatment Panel III metabolic syndrome criteria were randomly allocated into either a control, modified Dietary Approaches to Stop Hypertension (DASH) diet, or DASH and exercise group. Pre- and post-intervention demographic, cardiovascular health indicators, and plasma LCN2 expression were measured in each individual. While BMI fell in intervention groups, LCN2 levels remained unchanged within and between all groups, as illustrated by strong correlations between LCN2 concentrations pre- and 12 weeks post-intervention (r = 0.743, P < 0.0001). This suggests that circulating LCN2 expression are stable over a period of at least 12 weeks and is not modifiable by diet and exercise.

Conclusive evidence demonstrates that the sympathetic nervous system activation is a hallmark of congestive heart failure. This has been shown via a variety of biochemical, neurophysiological, and neuroimaging approaches for studying human sympathetic neural function. The sympathetic activation appears to be an early phenomenon in the clinical course of the disease, closely related to its severity and potentiated by the concomitant presence of other comorbidities, such as obesity, diabetes mellitus, metabolic syndrome, hypertension, and renal failure. The adrenergic overdrive in heart failure is associated with other sympathetic abnormalities, such as the downregulation of beta-adrenergic adrenoreceptors at cardiac level, and exerts unfavorable consequences on the cardiovascular system. These include the endothelial dysfunction, the development of left ventricular hypertrophy, the atherosclerosis development, as well as the generation of atrial and ventricular arrhythmias, and, at very extreme levels of sympathetic activation, the occurrence of microscopic myocardial necrosis. Given the close direct independent relationships detected in heart failure between sympathetic activation and mortality, the adrenergic overdrive has become a target of neuromodulatory therapeutic interventions, which include non-pharmacological, pharmacological, and device-based interventions. For some of these approaches (specifically bilateral renal nerves ablation and carotid baroreceptor stimulation), additional studies are needed to better define their impact on the clinical course of the disease.

Chronic kidney disease (CKD) is associated with greater sympathetic nerve activity but it is unclear if this is a kidney-specific response or due to generalized stimulation of sympathetic nervous system activity. To determine this, we used a rabbit model of CKD in which quantitative comparisons with control rabbits could be made of kidney sympathetic nerve activity and whole-body norepinephrine spillover. Rabbits either had surgery to lesion 5/6 th of the cortex of one kidney by electro-lesioning and two weeks later removal of the contralateral kidney, or sham lesioning and sham nephrectomy. After three weeks, the blood pressure was statistically significantly 20% higher in conscious rabbits with CKD compared to rabbits with a sham operation, but their heart rate was similar. Strikingly, kidney nerve activity was 37% greater than in controls, with greater burst height and frequency. Total norepinephrine spillover was statistically significantly lower by 34%, and kidney baroreflex curves were shifted to the right in rabbits with CKD. Plasma creatinine and urine output were elevated by 38% and 131%, respectively, and the glomerular filtration rate was 37% lower than in sham-operated animals (all statistically significant). Kidney gene expression of fibronectin, transforming growth factor-β, monocyte chemotactic protein1, Nox4 and Nox5 was two- to eight-fold greater in rabbits with CKD than in control rabbits. Overall, the glomerular layer lesioning model in conscious rabbits produced a moderate, stable degree of CKD characterized by elevated blood pressure and increased kidney sympathetic nerve activity. Thus, our findings, together with that of a reduction in total norepinephrine spillover, suggest that kidney denervation, rather than generalized sympatholytic treatments, may represent a preferable management for CKD associated hypertension., (Copyright © 2020 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Aims: To determine whether renal denervation (RDN) in hypertensive patients affects the platelet activation status., Methods and Results: We investigated the effect of RDN on the platelet activation status in 41 hypertensive patients undergoing RDN. Ambulatory blood pressure (BP), plasma sympathetic neurotransmitter Neuropeptide Y, and platelet activation markers were measured at baseline, at 3 months, and 6 months after RDN. RDN significantly decreased BP at 3 months (150.6 ± 11.3/80.9 ± 11.4 mmHg to 144.7 ± 12.0/77.1 ± 11.1 mmHg; P < 0.01) and at 6 months (144.3 ± 13.8/78.3 ± 11.1 mmHg; P < 0.01). Plasma levels of the sympathetic neurotransmitter Neuropeptide Y, an indicator of sympathetic nerve activity, were significantly decreased at 3 months (0.29 ± 0.11 ng/mL to 0.23 ± 0.11 ng/mL; P < 0.0001) and at 6 months (0.22 ± 0.12 ng/mL; P < 0.001) after RDN. This was associated with a reduction in platelet membrane P-selectin expression (3 months, P < 0.05; 6 months, P < 0.05), soluble P-selectin (6 months, P < 0.05), circulating numbers of platelet-derived extracellular vesicles (EVs) (3 months, P < 0.001; 6 months, P < 0.01), and phosphatidylserine expressing EVs (3 months, P < 0.001; 6 months, P < 0.0001), indicative of a reduction in platelet activation status and procoagulant activity. Only patients who responded to RDN with a BP reduction showed inhibition of P-selectin expression at 3 months (P < 0.05) and 6 months (P < 0.05) as well as reduction of glycoprotein IIb/IIIa activation at 3 months (P < 0.05). Notably, 13 patients who took aspirin did not show significant reduction in platelet P-selectin expression following RDN., Conclusion: Our results imply a connection between the sympathetic nervous system and the platelet activation status and provide a potential mechanistic explanation by which RDN can have favourable effects towards reducing cardiovascular complications., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Pseudopheochromocytoma manifests as severe, symptomatic paroxysmal hypertension without significant elevation in catecholamine and metanephrine levels and lack of evidence of tumor in the adrenal gland. The clinical manifestations are similar but not identical to those in excess circulating catecholamines. The underlying symptomatic mechanism includes augmented cardiovascular responsiveness to catecholamines alongside heightened sympathetic nervous stimulation. The psychological characteristics are probably attributed to the component of repressed emotions related to a past traumatic episode or repressive coping style. Successful management can be achieved by strong collaboration between a hypertension specialist and a psychiatrist or psychologist with expertise in cognitive-behavioral panic management., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Initial studies of catheter-based renal denervation (RDN) for uncontrolled HTN using radiofrequency ablation in the main renal arteries showed that RDN was effective in lowering office blood pressure (BP). However, the first randomized sham-controlled trial, SYMPLICITY-HTN-3, did not show significantly lower office or 24-h ambulatory systolic BP compared with sham treatment. Subsequent studies in both animals and humans demonstrated the potential importance of more distal and branch renal artery radiofrequency ablation, and a second-generation multielectrode system became available. Two recent randomized sham-controlled trials in patients not taking antihypertensive drugs (SPYRAL HTN-OFF MED) or continuing to take drugs (SPYRAL HTN-ON MED) performed RDN with the second-generation radiofrequency ablation system using an ablation protocol that included treatment of the distal renal artery as well as the branch renal arteries. These studies showed that RDN significantly reduced office and 24-h ambulatory BP compared with sham treatment. Another recent randomized sham-controlled trial in patients not receiving medications showed that RDN with catheter-based ultrasound (RADIANCE-HTN SOLO) applied in just the main renal arteries significantly lowered daytime ambulatory and office BP compared with sham treatment. These trials have renewed clinical and scientific interest in defining the appropriate role of RDN in hypertension treatment. In addition, other important issues will need to be addressed in the future such as the development of tests to determine the extent of RDN at the time of the procedure and the potential of renal nerve fibers to regain their patency at some later stage following the ablation procedure., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Three recent renal denervation studies in both drug-naïve and drug-treated hypertensive patients demonstrated a significant reduction of ambulatory blood pressure compared with respective sham control groups. Improved trial design, selection of relevant patient cohorts, and optimized interventional procedures have likely contributed to these positive findings. However, substantial variability in the blood pressure response to renal denervation can still be observed and remains a challenging and important problem. The International Sympathetic Nervous System Summit was convened to bring together experts in both experimental and clinical medicine to discuss the current evidence base, novel developments in our understanding of neural interplay, procedural aspects, monitoring of technical success, and others. Identification of relevant trends in the field and initiation of tailored and combined experimental and clinical research efforts will help to address remaining questions and provide much-needed evidence to guide clinical use of renal denervation for hypertension treatment and other potential indications., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Renal sympathetic denervation (RDN) is under investigation as a treatment option in patients with resistant hypertension (RH). Determinants of arterial compliance may, however, help to predict the BP response to therapy. Aortic distensibility (AD) is a well-established parameter of aortic stiffness and can reliably be obtained by CMR. This analysis sought to investigate the effects of RDN on AD and to assess the predictive value of pre-treatment AD for BP changes. We analyzed data of 65 patients with RH included in a multicenter trial. RDN was performed in all participants. A standardized CMR protocol was utilized at baseline and at 6-month follow-up. AD was determined as the change in cross-sectional aortic area per unit change in BP. Office BP decreased significantly from 173/92 ± 24/16 mmHg at baseline to 151/85 ± 24/17 mmHg (p < 0.001) 6 months after RDN. Maximum aortic areas increased from 604.7 ± 157.7 to 621.1 ± 157.3 mm 2 (p = 0.011). AD improved significantly by 33% from 1.52 ± 0.82 to 2.02 ± 0.93 × 10 -3 mmHg -1 (p < 0.001). Increase of AD at follow-up was significantly more pronounced in younger patients (p = 0.005) and responders to RDN (p = 0.002). Patients with high-baseline AD were significantly younger (61.4 ± 10.1 vs. 67.1 ± 8.4 years, p = 0.022). However, there was no significant correlation of baseline AD to response to RDN. AD is improved after RDN across all age groups. Importantly, these improvements appear to be unrelated to observed BP changes, suggesting that RDN may have direct effects on the central vasculature.

Renal afferent and efferent sympathetic nerves are involved in the regulation of blood pressure and have a pathophysiological role in hypertension. Additionally, several conditions that frequently coexist with hypertension, such as heart failure, obstructive sleep apnea, atrial fibrillation, renal dysfunction, and metabolic syndrome, demonstrate enhanced sympathetic activity. Renal denervation (RDN) is an approach to reduce renal and whole body sympathetic activation. Experimental models indicate that RDN has the potential to lower blood pressure and prevent cardio-renal remodeling in chronic diseases associated with enhanced sympathetic activation. Studies have shown that RDN can reduce blood pressure in drug-naïve hypertensive patients and in hypertensive patients under drug treatment. Beyond its effects on blood pressure, sympathetic modulation by RDN has been shown to have profound effects on cardiac electrophysiology and cardiac arrhythmogenesis. RDN can display anti-arrhythmic effects in a variety of animal models for atrial fibrillation and ventricular arrhythmias. The first non-randomized studies demonstrate that RDN may promote the maintenance of sinus rhythm following catheter ablation in patients with atrial fibrillation. Registry data point towards a beneficial effect of RDN to prevent ventricular arrhythmias in patients with heart failure and electrical storm. Further large randomized placebo-controlled trials are needed to confirm the antihypertensive and anti-arrhythmic effects of RDN. Here, we will review the current literature on anti-arrhythmic effects of RDN with the focus on atrial fibrillation and ventricular arrhythmias. We will discuss new insights from preclinical and clinical mechanistic studies and possible clinical implications of RDN.

Objectives: Noradrenaline released from sympathetic nerves is rapidly inactivated via the action of the noradrenaline transporter (NET). We aimed to determine whether a single nucleotide polymorphism (SNP) in the NET gene, rs7194256, was associated with blood pressure and plasma noradrenaline concentration in patients with resistant hypertension., Methods: Ninety-two consecutive patients with resistant hypertension participated in this study (age 62 ± 1.3 years, BMI 32 ± 0.6 kg/m, mean ± SEM). Blood pressure was assessed using 24-h ambulatory blood pressure monitoring. Genotyping of rs7194256 (C/T) was performed using a predeveloped TaqMan SNP Genotyping Assay. Plasma catecholamines were analyzed using high-performance liquid chromatography., Results: There were no differences in anthropometric measures between those carrying a T allele or the CC genotype. Patients carrying a T allele had significantly higher SBP: 24-h mean 148 ± 2.6 vs. 140 ± 2.4; 24-h max 189 ± 3.2 vs. 179 ± 2.6; 24-h min 114 ± 3.0 vs. 105 ± 2.3; night mean 141 ± 3.0 vs. 131 ± 2.5; night max 170 ± 3.6 vs. 159 ± 3.1; night min 118 ± 3.4 vs. 109 ± 2.4 (all P < 0.05). T-allele carriers had a significantly higher arterial noradrenaline concentration: 573 ± 53 vs. 377 ± 35 pg/ml (P = 0.002) and lower ratio of the intraneuronal noradrenaline metabolite, 3,4-dihydroxyphenylglycol, to noradrenaline (3.01 ± 0.4 vs. 4.08 ± 0.3 pg/ml; P = 0.024)., Conclusion: A SNP in the NET gene in patients with resistant hypertension is associated with higher plasma noradrenaline concentration and elevated SBP. Impaired NET function may be a contributor to the pronounced activation of the sympathetic nervous system characteristic of patients with resistant hypertension.

Background: Renal denervation (RDN) can reduce blood pressure (BP) in patients with resistant hypertension, but less so in patients with isolated systolic hypertension. A possible explanation is that patients with stiffer arteries may have lesser neural contribution to their hypertension., Method: We hypothesized that arterial stiffness predicts the response to RDN. From ambulatory BP monitoring (ABPM), ambulatory arterial stiffness index (AASI) was calculated as 1 - the regression slope of DBP versus SBP., Results: In 111 patients with resistant hypertension, RDN reduced office and 24-h SBP after 3, 6, and 12 months (by -11 ± 22, -11 ± 25, -14 ± 21 mmHg for office, and -4 ± 11, -5 ± 12, -5 ± 15 mmHg for 24-h SBP, respectively, P < 0.01). Patients with baseline AASI above the median (>0.51) showed no change in 24-h SBP at 6 months after RDN (-0.4 ± 12.3 mmHg, P > 0.05), whereas an AASI below 0.51was associated with a marked reduction (-9.3 ± 11.0 mmHg, P < 0.01). Across AASI quartiles, patients in the highest quartile (AASI ≥ 0.60) had lower muscle sympathetic nerve activity than the other three quartiles (39 ± 13 versus 49 ± 13 bursts/min, P = 0.035). The responder rate, defined as a 24-h SBP reduction of at least 5% was 58% in the lowest AASI quartile (<0.45) and 16% in the highest quartile (≥0.60). After adjustment for age, sex, BMI, office and 24-h SBP, an AASI less than 0.51predicted those who respond to RDN (odds ratio 3.46, P = 0.04)., Conclusion: We conclude that in patients with resistant hypertension, a lower AASI is an independent predictor of the BP response to RDN, possibly explained by a more pronounced neurogenic rather than biomechanical contribution to their BP elevation.

Pure autonomic failure (PAF) is a rare sporadic disorder characterized by autonomic failure in the absence of a movement disorder or dementia and is associated with very low plasma norepinephrine (NE) levels-suggesting widespread sympathetic denervation, however due to its rarity the pathology remains poorly elucidated. We sought to correlate clinical and neurochemical findings with sympathetic nerve protein abundances, accessed by way of a forearm vein biopsy, in patients with PAF and in healthy controls and patients with multiple systems atrophy (MSA) in whom sympathetic nerves are considered intact. The abundance of sympathetic nerve proteins, extracted from forearm vein biopsy specimens, in 11 patients with PAF, 8 patients with MSA and 9 age-matched healthy control participants was performed following a clinical evaluation and detailed evaluation of sympathetic nervous system function, which included head-up tilt (HUT) testing with measurement of plasma catecholamines and muscle sympathetic nerve activity (MSNA) in addition to haemodynamic assessment to confirm the clinical phenotype. PAF participants were found to have normal abundance of the NE transporter (NET) protein, together with very low levels of tyrosine hydroxylase (TH) ( P <0.0001) and reduced vesicular monoamine transporter 2 (VMAT2) ( P <0.05) protein expression compared with control and MSA participants. These findings were associated with a significantly higher ratio of plasma 3,4-dihydroxyphenylglycol (DHPG):NE in PAF participants when compared with controls ( P <0.05). The finding of normal NET abundance in PAF suggests intact sympathetic nerves but with reduced NE synthesis. The finding of elevated plasma ratio of DHPG:NE and reduced VMAT2 in PAF indicates a shift towards intraneuronal NE metabolism over sequestration in sympathetic nerves and suggests that sympathetic dysfunction may occur ahead of denervation., (© 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)