Autonomic Cardiovascular Alterations in Chronic Kidney Disease: Effects of Dialysis, Kidney Transplantation, and Renal Denervation

The autonomic nervous system and bone health in chronic kidney disease

Besides the well-known role of hormonal factors in mineral and bone metabolism, the sympathetic nervous system participates in this regulation by inhibiting bone formation and promoting bone resorption, primarily via β-adrenergic receptors expressed on osteoblasts. Conversely, the parasympathetic system, through cholinergic signalling, inhibits osteoclast activity, promoting bone formation and maintaining skeletal homeostasis. This review presents the role of the autonomic nervous system, with particular focus on the potential role of β-blockers, especially β1-selective blockers, in modulating bone health in people with normal kidney function and those with CKD. While early studies with non-selective β-blockers like propranolol showed mixed results, recent findings in postmenopausal women suggested that β1-selective β-blockers could enhance bone density by modulating sympathetic activity. Trial emulation using large databases and eventually randomized controlled trials are needed to test the hypothesis that β-blockade can favourably impact bone disease in patients with kidney failure.

Renalase, dopamine, and norepinephrine as markers for the development of hypertension in CKD patients

INTRODUCTION

Chronic kidney disease (CKD) leads to irreversible changes in kidney function and structure, with over 90% of patients developing arterial hypertension (HT). Renalase, dopamine, and norepinephrine are believed to influence HT development and CKD progression.

AIM OF THE STUDY

This study aims to measure renalase, dopamine, and norepinephrine levels in CKD patients to evaluate their potential as markers for CKD progression, HT development, and cardiovascular event risk.

MATERIALS AND METHODS

The study involved 117 CKD patients divided into four groups: 32 hemodialysis patients (before and after treatment), 31 peritoneal dialysis patients, 24 kidney transplant recipients (pre- and post-transplant), and 30 conservatively treated patients (CKD stages 2-5). A control group included 31 healthy volunteers. Levels of renalase, dopamine, and norepinephrine were measured using the ELISA method.

RESULTS

The study found that CKD significantly affected renalase, dopamine, and norepinephrine levels (p = 0.046; p = 0.035; p = 0.023). The lowest renalase levels were in patients with ADPKD and HT, while the highest dopamine levels were in those with CKD due to glomerulonephritis. The lowest norepinephrine levels were observed in patients with HT and diabetes.

CONCLUSIONS

Levels of renalase, dopamine, and norepinephrine may indicate CKD progression, cardiovascular event risk, and patient prognosis.

Multi-Organ Denervation: The Past, Present and Future

The sympathetic division of the autonomic nervous system plays a crucial role in maintaining homeostasis, but its overactivity is implicated in various pathological conditions, including hypertension, hyperglycaemia, heart failure, and rheumatoid arthritis. Traditional pharmacotherapies often face limitations such as side effects and poor patient adherence, thus prompting the exploration of device-based multi-organ denervation as a therapeutic strategy. Crucially, this procedure can potentially offer therapeutic benefits throughout the 24 h circadian cycle, described as an "always-on" effect independent of medication compliance and pharmacokinetics. In this comprehensive review, we evaluate the evidence behind targeted multi-organ sympathetic denervation by considering the anatomy and function of the autonomic nervous system, examining the evidence linking sympathetic nervous system overactivity to various cardiometabolic and inflammatory conditions and exploring denervation studies within the literature. So far, renal denervation, developed in 2010, has shown promise in reducing blood pressure and may have broader applications for conditions including arrhythmias, glucose metabolism disorders, heart failure, chronic kidney disease and obstructive sleep apnoea. We review the existing literature surrounding the denervation of other organ systems including the hepatic and splenic arteries, as well as the pulmonary artery and carotid body, which may provide additional physiological benefits and enhance therapeutic effects if carried out simultaneously. Furthermore, we highlight the challenges and future directions for implementing multi-organ sympathetic ablation, emphasising the need for further clinical trials to establish optimal procedural technique, efficacy and safety.

Diagnostic accuracy of Bellavere's score in cardiac autonomic neuropathy among chronic kidney disease patients: a study of prevalence and dialysis impact

Background

Cardiac autonomic neuropathy (CAN) is a significant complication in chronic kidney disease (CKD), leading to increased morbidity and mortality. Early detection is essential for managing CKD patients effectively, especially those on hemodialysis. This study evaluated the prevalence CAN in CKD and diagnostic accuracy of Bellavere's Score in predicting CAN in CKD patients, including those undergoing hemodialysis.

Methods

This prospective observational study included 200 CKD patients. Cardiac autonomic neuropathy was assessed using Bellavere's Score, calculated through a series of autonomic function tests including heart rate variability and blood pressure responses. Bellavere's Score was measured pre-and post-dialysis in hemodialysis patients. The diagnostic performance of the score was evaluated using receiver operating characteristic (ROC) curves to determine sensitivity, specificity, and likelihood ratios.

Results

Among the patients, 60% were diagnosed with CAN, with 35% having early CAN and 24% severe CAN. Bellavere's Score showed high diagnostic accuracy across CKD stages, with sensitivity ranging from 75 to 89.29% and specificity from 69.09 to 96%. In CKD stage III patients, the sensitivity was 78.57% and specificity 91.4%. In stage V, sensitivity increased to 89.29%, though specificity dropped to 69.09%. For hemodialysis patients, Bellavere's Score exhibited a sensitivity of 79.78% and specificity of 79.28%. The prevalence of CAN decreased significantly from 79.8% pre-dialysis to 64% post-dialysis (p < 0.01).

Conclusion

Bellavere's Score provides a reliable and non-invasive approach for diagnosing CAN in CKD patients, with strong diagnostic performance across different disease stages and in hemodialysis. Larger studies are warranted to further validate its utility.

Association between the age-adjusted Charlson Comorbidity Index and complications after kidney transplantation: a retrospective observational cohort study

BACKGROUND

Complications following kidney transplantation elevate the risks of readmission and mortality. The aim of this study was to assess the association between the age-adjusted Charlson Comorbidity Index (ACCI) and postoperative complications among kidney transplant (KT) recipients.

METHODS

Between January 2015 and March 2021, a study involving 886 kidney transplant recipients at the Third Affiliated Hospital of Sun Yat-sen University was conducted. Postoperative complications were defined by the Clavien-Dindo Classification of Surgical Complications. Target Maximum Likelihood Estimation (TMLE) was employed to assess the association between ACCI and postoperative complications. The odds ratio (OR) was computed to determine the relationship between ACCI and postoperative complications. Subsequent interaction and stratified analyses were performed to assess the robustness of the findings.

RESULTS

Out of 859 KT participants ultimately included in the study, 30.7% were documented to have encountered postoperative complications. Participants with an ACCI value exceeding 3 exhibited a notably increased risk of postoperative complications following multivariable adjustment [aOR = 1.64, 95% CI [1.21,2.21], p = 0.001]. Congestive heart failure (OR = 16.18, 95% CI [1.98-132.17], p < 0.001), peripheral vascular disease (OR = 2.32, 95% CI [1.48-3.78], p < 0.001), and chronic obstructive pulmonary disease (OR = 6.05, 95% CI [2.95-12.39], p < 0.001) emerged as the top three preoperative comorbidities significantly linked to postoperative complications in ACCI.

CONCLUSION

An ACCI value exceeding 3 preoperatively constituted a risk factor for postoperative complications among KT patients.

Brain natriuretic peptide and N-terminal pro b-type natriuretic peptide in kidney transplantation: More than just cardiac markers

Although kidney transplantation (KT) is the best treatment option for most patients with end-stage kidney disease (ESKD) due to reduced mortality, morbidity and increased quality of life, long- term complications such as chronic kidney allograft dysfunction (CKAD) and increased cardiovascular disease burden are still major challenges. Thus, routine screening of KT recipients (KTRs) is very important to identify and quantify risks and guide preventative measures. However, no screening parameter has perfect sensitivity and specificity, and there is unmet need for new markers. In this review, we evaluate brain natriuretic peptide (BNP) and N-terminal pro b-type natriuretic peptide (NT-proBNP) as promising markers for risk stratification in the kidney transplant recipients (KTRs). The usefulness of these markers are already proven in heart failure, hypertension, coronary artery disease. In the context of KT, evidence is emerging. BNP and NT-proBNP has shown to be associated with kidney function, graft failure, echocardiographic parameters, major cardiovascular events and mortality but the underlying mechanisms are not known. Although BNP and NT-proBNP interact with immune system, renin angiotensin system and sympathetic system; it is not known whether these interactions are responsible for the clinical findings observed in KTRs. Future studies are needed whether these biomarkers show clinical efficacy, especially with regard to hard outcomes such as major adverse cardiovascular events and graft dysfunction and whether routine implementation of these markers are cost effective in KTRs.

Non-invasive approaches to hydration assessment: a literature review

Traditional hydration assessment methods, while accurate, are often invasive and impractical for routine monitoring. In response, innovative non-invasive techniques such as bioelectrical impedance analysis (BIA), electrodermal activity (EDA), electrocardiogram (ECG) monitoring, and urine color charts have emerged, offering greater comfort and accessibility for patients. These methods use various types of sensors to capture a range of bio-signals, followed by machine learning-based classification or regression methods, providing real-time feedback on hydration status, which is crucial for effective management and prevention of urinary stones. This review explores the principles, applications, and efficacy of these non-invasive techniques, highlighting their potential to transform hydration monitoring in clinical and everyday settings. By facilitating improved patient compliance and enabling proactive hydration management, these approaches align with contemporary trends in personalized healthcare. This article presents a literature review on non-invasive approaches to hydration assessment, focusing on their significance in preventing kidney stone disease and enhancing kidney health.

The Clinical Significance and Application of Heart Rate Variability in Dialysis Patients: A Narrative Review

Autonomic nervous system (ANS) dysfunction is prevalent in end-stage kidney disease (ESKD) patients, carrying significant risks for morbidity and mortality. Heart rate variability (HRV) is a simple and non-invasive method to evaluate ANS functions and predict prognoses in specific patient populations. Since there is a lack of a clear understanding of the clinical significance of HRV in predicting prognoses in ESKD patients, an updated review on this topic is urgently warranted. The clinical significance of HRV in dialysis patients includes its associations with metabolic syndrome, nutritional status, intradialytic hypotension, vascular access failure, major adverse cardiovascular events, and mortality. These findings underscore the essential role of the autonomic reserve, which might denote the elevation of ANS activity as a response to external stimulus. Patients with a higher level of sympathetic activity at the resting stage, but who are unable to adequately elevate their sympathetic activity under stress might be susceptible to a worse outcome in critical circumstances. Further applications of HRV include HRV biofeedback, risk classification, and real-time HRV monitoring. Overall, HRV is an optimal tool for predicting prognoses in dialysis patients. Further study is encouraged in order to gain a clearer understanding of the clinical significance and application of HRV, and thereby enhance the care of ESKD patients.

Characterization of heart rate variability in end-stage renal disease patients after kidney transplantation with recurrence quantification analysis

Heart rate variability (HRV) is a noninvasive approach to studying the autonomic modulation of heart rate in experimental settings, such as active standing sympathetic stimulation. It is known that patients with end-stage renal disease during active standing have few changes in HRV dynamics, which are improved after hemodialysis. However, it is unknown whether the response to active standing is recovered after definitive treatment with kidney transplantation. This work aims to assess the change in HRV dynamics in the supine position and active standing through time and frequency-based metrics, as well as recurrence plot quantitative analysis (RQA). We studied HRV dynamics by obtaining 5-minute electrocardiographic recordings from kidney transplant recipients who underwent an active standing test. The mean duration of heartbeats and their standard deviation diminished in active standing, compared with the supine position. Also, the low-frequency component of HRV and the presence of diagonal and vertical structures in RQA were predominant. A larger estimated glomerular filtration rate was significantly correlated with broader HRV in the supine position and during active standing. The narrower HRV during active standing may indicate a sympathetic response to external stimuli, which is expected in a functional cardiovascular system, and may be influenced by renal function.

Renal Denervation in End-Stage Renal Disease: Current Evidence and Perspectives

In patients with end-stage renal disease (ESRD) undergoing haemodialysis, hypertension is of common detection and frequently inadequately controlled. Multiple pathophysiological mechanisms are involved in the development and progression of the ESRD-related high blood pressure state, which has been implicated in the increased cardiovascular risk reported in this hypertensive clinical phenotype. Renal sympathetic efferent and afferent nerves play a relevant role in the development and progression of elevated blood pressure values in patients with ESRD, often leading to resistant hypertension. Catheter-based bilateral renal nerves ablation has been shown to exert blood pressure lowering effects in resistant hypertensive patients with normal kidney function. Promising data on the procedure in ESRD patients with resistant hypertension have been reported in small scale pilot studies. Denervation of the native non-functioning kidney's neural excitatory influences on central sympathetic drive could reduce the elevated cardiovascular morbidity and mortality seen in ESRD patients. The present review article will focus on the promising results obtained with renal denervation in patients with ESRD, its mechanisms of action and future perspectives in these high risk patients.

Renal Denervation in the Treatment of Resistant Hypertension and Difficult-to-Control Hypertension - Consensus Document of the Croatian Hypertension League - Croatian Society of Hypertension, Croatian Cardiac Society, Croatian Endovascular Initiative, Croatian Society for Diabetes and Metabolic Diseases, Croatian Renal Association, and Croatian Society of Family Physicians of the Croatian Medical Association

Renal denervation (RDN) as a method of treating arterial hypertension (AH) was introduced in Croatia in 2012. A multidisciplinary team and a network of hospitals that diagnose and treat patients with severe forms of AH were established, and a very strict diagnostic-treatment algorithm was prepared. At monthly meetings patients with truly resistant hypertension who were candidates for RDN were discussed. According to the 2021 ESH position statement and 2023 ESH guidelines, RDN is considered an alternative and additional, not a competitive method of treating patients with various forms of AH which must be performed by following a structured procedure and the patient's preference should be considered. In view of the changes in the global scientific community, the Croatian Hypertension League brings this consensus document on RDN conducted with radiofrequency-based catheter, the only currently available method in Croatia. In this document, exclusion and inclusion criteria are shown, as well as three groups of patients in whom RDN could be considered. The new diagnostic-treatment algorithm is prepared and follow-up procedure is explained. In Croatia, RDN is reimbursed by the national insurance company, thus pharmacoeconomic analyses is also shown. Criteria required by an individual centre to be approved of RDN are listed, and plans for prospective research on RDN in Croatia, including the Croatian registry for RDN, are discussed.

Possible organ-protective effects of renal denervation: insights from basic studies

Inappropriate sympathetic nervous activation is the body's response to biological stress and is thought to be involved in the development of various lifestyle-related diseases through an elevation in blood pressure. Experimental studies have shown that surgical renal denervation decreases blood pressure in hypertensive animals. Recently, minimally invasive catheter-based renal denervation has been clinically developed, which results in a reduction in blood pressure in patients with resistant hypertension. Accumulating evidence in basic studies has shown that renal denervation exerts beneficial effects on cardiovascular disease and chronic kidney disease. Interestingly, recent studies have also indicated that renal denervation improves glucose tolerance and inflammatory changes. In this review article, we summarize the evidence from animal studies to provide comprehensive insight into the organ-protective effects of renal denervation beyond changes in blood pressure.

Does Renal Denervation a Reasonable Treatment Option in Hemodialysis-Dependent Patient with Resistant Hypertension? A Narrative Review

PURPOSE OF REVIEW

This narrative review aims to assess the pathophysiology, diagnosis, and treatment of resistant hypertension (RH) in end-stage kidney disease (ESKD) patients on dialysis, with a specific focus on the effect of renal denervation (RDN) on short-term and long-term blood pressure (BP) control. Additionally, we share our experience with the use of RDN in an amyloidotic patient undergoing hemodialysis with RH.

RECENT FINDINGS

High BP, an important modifiable cardiovascular risk factor, is often observed in patients in ESKD, despite the administration of multiple antihypertensive medications. However, in clinical practice, it remains challenging to identify RH patients on dialysis treatment because of the absence of specific definition for RH in this context. Moreover, the use of invasive approaches, such as RDN, to treat RH is limited by the exclusion of patients with reduced renal function (eGFR < 45 mL/min/1.73 m3) in the clinical trials. Nevertheless, recent studies have reported encouraging results regarding the effectiveness of RDN in stage 3 and 4 chronic kidney disease (CKD) and ESKD patients on dialysis, with reductions in BP of nearly up to 10 mmhg. Although multiple underlying pathophysiological mechanisms contribute to RH, the overactivation of the sympathetic nervous system in ESKD patients on dialysis plays a crucial role. The diagnosis of RH requires both confirmation of adherence to antihypertensive therapy and the presence of uncontrolled BP values by ambulatory BP monitoring or home BP monitoring. Treatment involves a combination of nonpharmacological approaches (such as dry weight reduction, sodium restriction, dialysate sodium concentration reduction, and exercise) and pharmacological treatments. A promising approach for managing of RH is based on catheter-based RDN, through radiofrequency, ultrasound, or alcohol infusion, directly targeting on sympathetic overactivity.

The role of LncRNA-regulated autophagy in AKI

Acute kidney injury (AKI) is a complex clinical syndrome involving a series of pathophysiological processes regulated by multiple pathways at the molecular and cellular level. Long noncoding RNAs (lncRNAs) play an important role in the regulation of epigenetics, and their regulation of autophagy-related genes in AKI has attracted increasing attention. However, the role of lncRNA-regulated autophagy in AKI has not been fully elucidated. Evidence indicated that lncRNAs play regulatory roles in most factors that induce AKI. LncRNAs can regulate autophagy in AKI via a complex network of regulatory pathways to affect the development and prognosis of AKI. This article reviewed and analyzed the pathways of lncRNA regulation of autophagy in AKI in recent years. The results provide new ideas for further study of the pathophysiological process and targeted therapy for AKI.

Home-Based Exercise Training and Cardiac Autonomic Neuropathy in Kidney Transplant Recipients with Type-II Diabetes Mellitus

This randomized clinical trial aimed to examine the effects of a 6-month home-based, combined exercise training program on Cardiac Autonomic Neuropathy (CAN) in kidney transplant recipients (KTRs) with diabetes. Twenty-five KTRs (19 men (76.0%), with a mean age of 54.4 ± 11.3 years old, CAN and type II Diabetes Mellitus (DM-II)), were randomly assigned into two groups: A (n1 = 13 KTRs), who underwent a home-based exercise training program for 6 months, and B (n2 = 12 KTRs), who were assessed at the end of the study. A cardiopulmonary exercise testing (CPET), sit-to-stand test in 30 s (30-s STS), isokinetic muscle strength dynamometry, and 24-h electrocardiographic monitoring were applied to all participants, both at the baseline and at the end of the clinical trial. At first, there were no statistically significant differences between groups. After 6 months, group A showed higher values in exercise time by 8.7% (p = 0.02), VO2peak by 7.3% (p < 0.05), 30-s STS by 12.0% (p < 0.05), upper limb strength by 46.1% (p < 0.05), and lower limb strength by 24.6% (p = 0.02), respectively, compared to the B group. Furthermore, inter-group changes at the end of the 6-month study indicated that group A statistically increased the standard deviation of R-R intervals (SDNN) by 30.3% (p = 0.01), root mean square of successive differences between normal heartbeats (rMSSD) by 32.0% (p = 0.03), number of pairs of successive NN (R-R) intervals that differ by more than 50 ms (pNN50) by 29.0% (p = 0.04), high frequency (HF (ms2)) by 21.6% (p < 0.05), HF (n.u.) by 48.5% (p = 0.01), and turbulence slope (TS) by 22.5% (p = 0.02), and decreased the low frequency (LF (ms2)) by 13.2% (p = 0.01), LF (n.u.) by 24.9% (p = 0.04), and LF/HF ratio by 24% (p = 0.01), compared to group B. Linear regression analysis after the 6-month study showed that there was a strong positive correlation between VO2peak and SDNN (r = 0.701, p < 0.05) in group A. Moreover, multiple regression analysis showed that KTRs' participation in the exercise program showed favorable modifications to sympathovagal balance and aerobic capacity, as measured with SDNN and VO2peak, respectively. To summarize, diabetic KTRs' cardiac autonomic function and functional capacity can be improved after a home-based long-term exercise training program.

Non-dipping pulse rate and chronic changes of the kidney in patients with chronic kidney disease

Introduction

An insufficient decrease in nocturnal pulse rate (PR), non-dipping PR, reflects autonomic imbalance and is associated with cardiovascular events and all-cause mortality. We aimed to investigate the clinical and microanatomical structural findings associated with the non-dipping PR status in patients with chronic kidney disease (CKD).

Methods

This cross-sectional study included 135 patients who underwent ambulatory blood pressure monitoring and kidney biopsy concurrently at our institution between 2016 and 2019. Non-dipping PR status was defined as (daytime PR-nighttime PR)/daytime PR <0.1. We compared clinical parameters and microstructural changes in the kidney between patients with and without non-dipping PR, including 24 h proteinuria, glomerular volume, and Mayo Clinic/Renal Pathology Society Chronicity Score.

Results

The median age was 51 years (interquartile range: 35-63), 54% of which were male, and the median estimated glomerular filtration rate was 53.0 (30.0-75.0) mL/min/1.73 m². Non-dipping PR status was observed in 39 patients. Patients with non-dipping PR were older and had worse kidney function, higher blood pressure, greater prevalence of dyslipidemia, lower hemoglobin levels, and a larger amount of urinary protein excretion than patients with dipping PR. Patients with non-dipping PR had more severe glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arteriosclerosis. In the multivariable analysis, the severe chronic changes of the kidney were associated with non-dipping PR status after adjusting for age, sex, and other clinical parameters (odds ratio = 20.8; 95% confidence interval, 2.82-153; P = 0.003).

Conclusion

This study is the first to indicate that non-dipping PR is significantly associated with chronic microanatomical changes in the kidneys of patients with CKD.

Insight on Efficacy of Renal Artery Denervation for Refractory Hypertension with Chronic Kidney Diseases: A Long-Term Follow-Up of 24-Hour Ambulatory Blood Pressure

Aims

To explore the long-term efficacy and safety of renal denervation in patients with RHT and CKD, a post hoc analysis of eGFR subgroups was completed.

Methods

Fifty-four patients with refractory hypertension with chronic kidney disease were treated with RDN and enrolled in the study. Patients were divided into three groups according to eGFR: eGFR 46–90 ml/min group, eGFR 15–45 ml/min group, and eGFR <15 ml/min group. The planned follow-up period was 48 months to assess 24 h ambulatory blood pressure, renal function, type of antihypertensive medication, and RDN complications.

Results

The ablation sites of the GFR 46–90 ml/min group and GFR 15–45 ml/min group were 32.57 ± 2.99 and 29.53 ± 5.47, respectively. No complications occurred in the GFR 46–90 ml/min group. The GFR<15 ml/min group was treated with 27.07 ± 5.59  ablation. Renal artery dissection occurred in each group of GFR 15–45 ml/min and GFR <15 ml/min. And renal stent implantation artery was performed on these two patients. No severe renal artery stenosis occurred. There were no significant differences in Scr and eGFR between the three groups at each follow-up point. Compared with baseline, SBP was significantly of each group decreased to varying degrees at each follow-up time point. SBP decreased most in the GFR 46–90 ml/min group. Compared with baseline, the type of antihypertensive drugs used in the GFR46-90 ml/min group decreased significantly except for 36 and 48 months. At 48 months' postadmission, there was a significant decrease in the type of antihypertensive medication used in the GFR15-45 ml/min group, and there was no significant decrease in the type of antihypertensive medication used in the GFR<15 ml/min group.

Conclusions

RDN can safely reduce SBP in CKD patients combined with RHT for 48 months, with the most pronounced reduction in the GFR15-45 ml/min group. The variety of antihypertensive drugs was significantly reduced after RDN. This was particularly evident in patients with GFR 15–45 ml/min.

A parallel evaluation of short- and mid-term changes of ambulatory blood pressure in kidney transplant recipients and kidney donors

Introduction

Kidney transplantation (KTx) is associated with improved blood pressure (BP) levels for kidney transplant recipients (KTRs) without evoking significant changes in donors. However, there is a paucity of studies offering simultaneous detailed evaluation of BP profiles over time in transplant donor-recipient pairs. The aim of the present study was the parallel evaluation of ambulatory BP levels and trajectories in KTRs and their respective living kidney donors in the short and mid-term following KTx.

Methods

The study enrolled 40 prospective adult KTRs and their 40 respective donors. All participants were evaluated with 24-h ambulatory BP monitoring (Mobil-O-Graph NG device) at three time points: baseline (1 month before KTx), 3 months and 12 months after KTx.

Results

In KTRs, 3-month 24-h systolic BP (SBP) was marginally reduced and 12-month 24-h SBP significantly reduced compared with baseline [131.9 ± 13.3 versus 126.4 ± 11.9 mmHg (P = .075) and 123.9 ± 10.3 mmHg (P = .009),  respectively]. At both the 3- and 12-month time points, 24-h diastolic BP (DBP) was significantly reduced [86.7 ± 11.5 versus 82.2 ± 8.1 mmHg (P = .043) and 80.3 ± 8.5 mmHg (P = .009)]. Similar observations were made for day- and night time SBP and DBP. Repeated-measures analysis of variance (ANOVA) showed a significant gradual decrease over time in mean 24-h SBP [F(1.463, 39.505) = 3.616; P = .049, partial η ² = 0.118] and DBP [F(1.374, 37.089) = 11.34; P = .055, partial η ² = 0.116]. In contrast, in kidney donors, 24-h SBP [118.5 ± 11.6 versus 118.2 ± 12.8 mmHg (P = .626) and 119.2 ± 11.4 mmHg (P = .748)] and DBP did not change at 3 or 12 months compared with baseline; repeated measures ANOVA showed no differences in the mean 24-h SBP and DBP levels over time. The number of antihypertensive agents decreas in KTRs and remained stable in donors.

Conclusions

KTx reduces ambulatory BP levels and trajectories in KTRs at 3 months and further so at 12 months post-surgery. Kidney donation does not affect the ambulatory BP levels and trajectories of donors at the same intervals.

Ambulatory blood pressure trajectories and blood pressure variability in kidney transplant recipients: a comparative study against chronic kidney disease patients

Background

Methods

Results

Conclusion

Vagally Associated Second Degree Atrio-Ventricular Block in a Dog with Severe Azotemia and Evidence of Sympathetic Overdrive

A 14 years old, 6 kg, mix-breed male dog with severe azotemia due to urinary bladder herniation was presented to our Veterinary Teaching Hospital (VTH). Electrocardiography revealed normal heart rate of 100 bpm, evidence of sinus respiratory arrhythmia (SRA) and frequent second degree atrio-ventricular block following peak inspiratory phase suggestive of vagally-induced atrio-ventricular conduction delay. Echocardiographic examination showed mild mitral regurgitation without any other cardiac changes, and systolic (SAP) and diastolic (DAP) blood pressure values were 185/90 mmHg (SAP/DAP). Cardiac troponin I (cTnI) was increased to 7.3 ng/mL, suggesting a myocardial injury. A Holter examination revealed evidence of overall decrease in heart rate variability with evidence of sympathetic overdrive on time and frequency domain as well as when the non-linear Poincaré plot was analyzed. Based on the author's knowledge, this is the first report of a second degree atrio-ventricular block associated with vagal activity in a dog, with evidence of sympathetic overdrive and severe azotemia.

The sympathies of the body: functional organization and neuronal differentiation in the peripheral sympathetic nervous system

During the last 30 years, our understanding of the development and diversification of postganglionic sympathetic neurons has dramatically increased. In parallel, the list of target structures has been critically extended from the cardiovascular system and selected glandular structures to metabolically relevant tissues such as white and brown adipose tissue, lymphoid tissues, bone, and bone marrow. A critical question now emerges for the integration of the diverse sympathetic neuron classes into neural circuits specific for these different target tissues to achieve the homeostatic regulation of the physiological ends affected.

Clinical Relevance of the Sympathetic-Vascular Interactions in Health and Disease

The sympathetic nervous system is known to play a pivotal role in the short- and long-term regulation of different cardiovascular functions. In recent decades, increasing evidence has demonstrated that sympathetic neural influences are involved not only in the vasomotor modulation of small resistance arteries but also in the control of large arteries. Sympathetic activity and vascular function, which are key factors in the pathophysiology and prognosis of cardiovascular disease, are linked by a close relationship. Evidence from experimental studies indicates that the sympathetic nervous system is critically influenced, at the central and also at the peripheral level, by the most relevant factors regulating vascular function, namely nitric oxide, reactive oxygen species and endothelin. Additionally, there is evidence of a reciprocal influence between endothelial function and sympathetic mechanisms. This paper will provide an overview of the relationships between endothelial function and the sympathetic nervous system characterizing physiological states. It will also briefly mention the alterations described in cardiovascular disease, with particular emphasis on essential hypertension and congestive heart failure, i.e., the two pathological states in which endothelial dysfunction and neuroadrenergic activation appear to be relevant factors for determining cardiovascular prognosis.