Epidemiology and Mechanisms of Uremia-Related Cardiovascular Disease

Urea Memory: Transient Cell Exposure to Urea Causes Persistent Mitochondrial ROS Production and Endothelial Dysfunction

Urea at post-dialysis levels induces increased ROS in a number of cell types. The aim of this study was to determine whether urea-induced production of ROS remains elevated after urea is no longer present, and, if it does, to characterize its origin and effects. Human arterial endothelial cells were incubated with 20 mM urea for two days, and then cells were incubated for an additional two days in medium alone. Maximal ROS levels induced by initial urea continued at the same level despite urea being absent. These effects were prevented by either MnSOD expression or by Nox1/4 inhibition with GKT13781. Sustained urea-induced ROS caused a persistent reduction in mtDNA copy number and electron transport chain transcripts, a reduction in transcription of mitochondrial fusion proteins, an increase in mitochondrial fission proteins, and persistent expression of endothelial inflammatory markers. The SOD-catalase mimetic MnTBAP reversed each of these. These results suggest that persistent increases in ROS after cells are no long exposed to urea may play a major role in continued kidney damage and functional decline despite reduction of urea levels after dialysis.

Analysis of Hospitalizations in Simultaneous Pancreas-Kidney Transplant Recipients: A Single-center Experience in Poland

BACKGROUND

End-stage renal disease due to type 1 diabetes mellitus appears to be a regular indication for simultaneous pancreas and kidney transplantation (SPKT). Although transplantation improves a patient's health condition, it does not mean that all complications will be eliminated.

METHODS

We performed a retrospective analysis of 73 patients who underwent SPKT and follow-up between 1988 and 2015 at our institute. The number, duration, and reasons for hospitalization at 1, 5, 10, and 15 years after SPKT were analyzed.

RESULTS

The average number of hospitalizations at 1, 5, 10, 15 years after SPKT were 1.66, 0.39, 0.36, and 0.33, respectively. The main reason for hospitalization over the 15-year period was infections, at 32.4% (SD, 6.8%). Within the first year after SPKT, 6.8% of hospital admissions were caused by cytomegalovirus (CMV) infection. Over time, the percentage of hospitalizations for cardiovascular complications increased from 0.6% at 1 year to 29% at 12-15 years. Incidence of hospitalization due to cardiovascular complications correlated with a longer period of dialysis and a diagnosis of ischemic heart disease before transplant (r = 0.56, P = .004; r = 0.54, P < .0001, respectively). At 12-15 years after transplantation, 18.2% of hospitalizations were caused by secondary complications of diabetes.

CONCLUSION

The most common reason for hospitalization after SPKT is infectious complications. In the first year posttransplant, there is a high percentage of CMV infections. Hospitalization associated with cardiovascular complications was found to be most common in the latter follow-up period and showed a correlation with longer dialysis period.

Prevalence of atheromatous and non-atheromatous cardiovascular disease by age in chronic kidney disease

Background

Although chronic kidney disease (CKD) and age are major risk factors for cardiovascular disease (CVD), little is known about the relative proportions of atheromatous and non-atheromatous CVD by age in CKD patients.

Methods

We used baseline data from the French Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort of 3033 patients (65% men) with CKD Stages 3–4 to study crude and adjusted associations between age, the estimated glomerular filtration rate (eGFR), atheromatous CVD (coronary artery disease, peripheral artery disease and stroke) and non-atheromatous CVD (heart failure, cardiac arrhythmia and valvular heart disease).

Results

Mean age was 66.8 and mean Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) eGFR was 32.9 mL/min/1.73 m2. In the &lt;65, (65–74), (75–84) and ≥85 year age groups, the prevalence was, respectively, 18.7, 35.5, 42.9 and 37.8% for atheromatous CVD, and 14.9, 28.4, 38.1 and 56.4% for non-atheromatous CVD. After adjusting for albuminuria, sex and CVD risk factors, the odds ratio (OR) [95% confidence interval (CI)] for (65–74), (75–84) and ≥85 age groups (compared with the &lt;65 group) was, respectively, 1.99 (1.61–2.46), 2.89 (2.30–3.62), 2.72 (1.77–4.18) for atheromatous CVD and 2.07 (1.66–2.58), 3.15 (2.50–3.97), 7.04 (4.67–10.61) for non-atheromatous CVD. Compared with patients with an eGFR ≥30 mL/min/1.73 m2, those with an eGFR &lt;30 mL/min/1.73 m2 had a higher OR for atheromatous CVD [1.21 (1.01–1.44)] and non-atheromatous CVD [1.16 (0.97–1.38)].

Conclusions

In this large cohort of CKD patients, both atheromatous and non-atheromatous CVD were highly prevalent and more frequent in older patients. In a given age group, the prevalence of atheromatous and non-atheromatous CVD was similar (except for a greater prevalence of non-atheromatous CVD after 85).

Ultrasonic image analysis of longitudinal strain in uremic patients with preserved left ventricular ejection fraction

Background

Patients with uremia have high cardiovascular disease morbidity and mortality despite having normal left ventricular ejection fraction (LVEF). Longitudinal strain (LS) can be associated with subtle changes in LV systolic function. The aim of this study was to use two-dimensional speckle-tracking echocardiography (2DSTE) to assess subclinical LV myocardial dysfunction and to explore strain-changing regularities in uremic patients with LVEF ≥ 55%.

Methods

The study population included 40 uremic patients and 40 healthy volunteers. 2DSTE was performed on all participants to assess peak LS in the basal, mid and apical LV (BLS, MLS and ALS) and the respective time to peak LS (T-BLS, T-MLS, T-ALS).

Results

BLS, MLS, and ALS were significantly decreased in the uremic group relative to healthy controls and LS increased going in a basal to apical direction in both groups. T-BLS, T-MLS and T-ALS was significantly increased in the uremic group compared with the control group. In uremic patients, T-BLS, but not T-MLS or T-ALS, was significantly delayed relative to the control group. Bivariate analysis of creatinine (Cr) or urea nitrogen and strain parameters revealed a correlation only between ALS and Cr.

Conclusion

2DSTE can identify LV myocardial abnormalities in uremic patients with preserved LVEF at early stage, as well as some changing regularities of LS and T-LS in the left ventricle.

Left Ventricular Strain and Dyssynchrony in Young and Middle-Aged Peritoneal Dialysis Patients and Healthy Controls: A Case-Matched Study

BACKGROUND

This study aimed to evaluate the role of two-dimensional speckle-tracking imaging (2D-STI) and myocardial layer-specific analysis in evaluating early left ventricular (LV) myocardial function and systolic dyssynchrony in young and middle-aged uremic patients undergoing peritoneal dialysis (PD).

METHODS

We enrolled 31 PD patients aged ≤65 years with preserved LV ejection fraction (LVEF, ≥54%) as the PD group and 49 age-matched healthy people as the control group. Echocardiography was used to assess the left atrial diameter index (LADI, LAD/BSA), LV mass index (LVMI), LVEF, peak early diastolic velocity/late diastolic velocity (E/A) (measured by pulsed Doppler), and peak early diastolic velocity (by pulsed Doppler)/peak velocity of the early diastolic wave (by pulsed-wave tissue Doppler) (E/e'). Next, we used 2D-STI and myocardial layer-specific analysis to obtain longitudinal strains (LS) of the endocardium (LSendo), the myocardium (LSmyo), the epicardium (LSepi), and the global myocardium (GLS). Then, we measured the postsystolic index (PSI) to evaluate LV myocardial function. Time to peak LS (TTP) and peak strain dispersion (PSD) from 17 consecutive segments were assessed to quantify LV dyssynchrony.

RESULTS

Compared with the controls, PD patients had significantly increased LADI (p = 0.041), LVMI (p = 0.000), and E/e' (p = 0.009), but reduced LVEF (p = 0.000) and E/A (p = 0.000). The average values of GLS (GLS avg) (p = 0.01) and GLS of the apical 2-chamber view (p = 0.003), including the LSendo (p = 0.024), LSmyo (p = 0.024), and LSepi (p = 0.032), were significantly decreased in patients with PD compared with controls. In PSI, segments of LS were markedly delayed in the anterior septum (p = 0.047), anterior (p = 0.000) and septum wall (p = 0.024) from basal segments, anterior wall (p = 0.001) from middle segments, and anterior (p = 0.024) and inferior (p = 0.024) wall from apical segments. Moreover, PSD was significantly increased in PD patients (p = 0.015), while TTP was evidently delayed in the anterior septum (p = 0.004), anterior (p = 0.000) and posterior (p = 0.042) wall from basal segments, and inferior wall (p = 0.048) from apical segments.

CONCLUSIONS

Despite preserved LVEF, young and middle-aged PD patients developed LV dysfunction and myocardial systolic dyssynchrony earlier compared with controls.

Inverse Association Between Serum Non-High-Density Lipoprotein Cholesterol Levels and Mortality in Patients Undergoing Incident Hemodialysis

BACKGROUND

There is accumulating evidence that serum levels of non-high-density lipoprotein cholesterol (non-HDL-C) are a more accurate predictor of cardiovascular outcomes when compared with low-density lipoprotein cholesterol. However, we recently found that higher serum concentrations of triglycerides are associated with better outcomes in patients undergoing hemodialysis. Therefore, we hypothesized that the association of serum levels of non-HDL-C (which includes triglyceride-rich lipoproteins) with outcomes may also be different in patients undergoing hemodialysis when compared with other patient populations.

METHODS AND RESULTS

We studied the association of baseline and time-dependent serum levels of non-HDL-C with all-cause and cardiovascular mortality using Cox proportional hazard regression models in a nationally representative cohort of 50 118 patients undergoing incident hemodialysis from January 1, 2007, to December 31, 2011. In time-dependent models adjusted for case mix and surrogates of malnutrition and inflammation, a graded inverse association between non-HDL-C level and mortality was demonstrated with hazard ratios (95% confidence intervals) of the lowest (<60 mg/dL) and highest (≥160 mg/dL) categories: 1.88 (1.72-2.06) and 0.73 (0.64-0.83) for all-cause mortality and 2.07 (1.78-2.41) and 0.75 (0.60-0.93) for cardiovascular mortality, respectively (reference, 100-115 mg/dL). In analyses using baseline values, non-HDL-C levels <100 mg/dL were also associated with significantly higher mortality risk across all levels of adjustment. Similar associations were found when evaluating non-HDL/HDL cholesterol ratio and mortality, with the highest all-cause and cardiovascular mortality being observed in patients with decreased non-HDL/HDL-C ratio (<2.5).

CONCLUSIONS

Contrary to the general population, decrements in non-HDL-C and non-HDL/HDL cholesterol ratio were paradoxically associated with increased all-cause and cardiovascular mortality in patients undergoing incident hemodialysis. The underlying mechanisms responsible for these associations await further investigation.

Negative Correlation of Serum Adiponectin Levels With Carotid–Femoral Pulse Wave Velocity in Patients Treated With Hemodialysis

Purpose:

The aim of this study was to evaluate the relationship between serum adiponectin levels and carotid–femoral pulse wave velocity (cfPWV) in hemodialysis (HD) patients.

Method:

Blood samples were obtained from 120 HD patients. cfPWV was measured with a validated tonometry system (SphygmoCor; AtCor Medical, West Ryde, Australia). Serum adiponectin levels were measured using a commercially available enzyme-linked immunosorbent assay kit.

Results:

By univariate linear analysis of cfPWV in HD patients, we found that diabetes ( r = .281, p = .002), pre-HD body weight ( r = .194, p = .033), post-HD body weight ( r = .192, p = .036), waist circumference ( r =.210, p = .022), and body fat mass ( r = .194, p = .034) were positively correlated, whereas adiponectin level ( r = −.254, p = .005) was negatively correlated with cfPWV in HD patients. Multivariate forward stepwise linear regression analysis showed that diabetes (β = .274, p = .006) and adiponectin level (β = −.215, p = .016) were independent predictors of cfPWV in HD patients. Moreover, post-HD body weight (β = −.274, p = .041), waist circumference (β = −.311, p < .001), logarithmically transformed triglyceride level (log-TG; β = −.186, p = .031), and log-glucose (β = −.225, p = .008) were negatively associated with adiponectin levels in HD patients after multivariable forward stepwise linear regression analysis.

Conclusions:

Among HD patients, serum adiponectin level was inversely associated with cfPWV level, and post-HD body weight, waist circumference, log-TG, and log-glucose were negatively associated with adiponectin level.

Design of Carrageenan-Based Heparin-Mimetic Gel Beads as Self-Anticoagulant Hemoperfusion Adsorbents

The currently used hemoperfusion adsorbents such as activated carbon and ion-exchange resin show dissatisfactory hemocompatibility, and a large dose of injected heparin leads to the increasing cost and the risk of systematic bleeding. Natural polysaccharide adsorbents commonly have good biocompatibility, but their application is restricted by the poor mechanical strength and low content of functional groups. Herein, we developed an efficient, self-anticoagulant and blood compatible hemoperfusion adsorbent by imitating the structure and functional groups of heparin. Carrageenan and poly(acrylic acid) (PAA) cross-linked networks were built up by the combination of phase inversion of carrageenan and post-cross-linking of AA, and the formed dual-network structure endowed the beads with improved mechanical properties and controlled swelling ratios. The beads exhibited low protein adsorption amounts, low hemolysis ratios, low cytotoxicity, and suppressed complement activation and contact activation levels. Especially, the activated partial thromboplastin time, prothrombin time, and thrombin time of the gel beads were prolonged over 13, 18, and 4 times than those of the control. The self-anticoagulant and biocompatible beads showed good adsorption capacities toward exogenous toxins (560.34 mg/g for heavy metal ions) and endogenous toxins (14.83 mg/g for creatinine, 228.16 mg/g for bilirubin, and 18.15 mg/g for low density lipoprotein (LDL)), thus, highlighting their potential usage for safe and efficient blood purification.

Stroke risk and outcomes in patients with chronic kidney disease or end-stage renal disease: Two nationwide studies

Background and aims

Because the risk and outcomes of stroke in patients with chronic kidney disease (CKD) or end-stage renal disease (ESRD) were unclear, we evaluated these risks using a retrospective cohort study and a nested cohort study.

Methods

We used Taiwan’s National Health Insurance Research Database to identify 1378 patients aged ≥20 years who had ESRD in 2000–2004. An age- and sex-matched CKD cohort (n = 5512) and a control cohort (n = 11,024) were selected for comparison. Events of incident stroke were considered as outcome during the follow-up period in 2000–2013, and we calculated adjusted hazard ratios (HR) and 95% CIs of stroke associated with CKD or ESRD. We further used matching procedure with propensity score to estimate the risk of stroke for control group, CKD patients, and EDRD patients. A nested cohort study of 318,638 hospitalized stroke patients between 2000 and 2010 also was conducted to analyze the impact of CKD and ESRD on post-stroke mortality.

Results

Before propensity-score matching, the incidences of stroke for controls, CKD patients and ESRD patients were 6.57, 13.3, and 21.7 per 1000 person-years, respectively. Compared with control group, the adjusted HRs of stroke were 1.49 (95% CI, 1.32–1.68) and 2.39 (95% CI, 1.39–2.87) for people with CKD or ESRD respectively, and were significantly higher in both sexes and every age group. After propensity-score matching, the HRs of stroke for patients with CKD and ESRD were 1.51 (95% CI 1.24–1.85) and 2.08 (95% CI 1.32–3.26), respectively, during the follow-up period. Among hospitalized stroke patients, adjusted rate ratio (RR) of post-stroke mortality in CKD and ESRD cohorts were 1.44 (95% CI, 1.33–1.56) and 2.62 (95% CI, 2.43–2.82) respectively compared with control.

Conclusions

CKD and ESRD patient groups thus faced significantly higher risk of stroke and post-stroke mortality. Risk factor identification and preventive strategies are needed to minimize stroke risk and post-stroke mortality in these vulnerable patient groups.

Value of Excess Pressure Integral for Predicting 15-Year All-Cause and Cardiovascular Mortalities in End-Stage Renal Disease Patients

BACKGROUND

The excess pressure integral (XSPI), derived from analysis of the arterial pressure curve, may be a significant predictor of cardiovascular events in high-risk patients. We comprehensively investigated the prognostic value of XSPI for predicting long-term mortality in end-stage renal disease patients undergoing regular hemodialysis.

METHODS AND RESULTS

A total of 267 uremic patients (50.2% female; mean age 54.2±14.9 years) receiving regular hemodialysis for more than 6 months were enrolled. Cardiovascular parameters were obtained by echocardiography and applanation tonometry. Calibrated carotid arterial pressure waveforms were analyzed according to the wave-transmission and reservoir-wave theories. Multivariable Cox proportional hazard models were constructed to account for age, sex, diabetes mellitus, albumin, body mass index, and hemodialysis treatment adequacy. Incremental utility of the parameters to risk stratification was assessed by net reclassification improvement. During a median follow-up of 15.3 years, 124 deaths (46.4%) incurred. Baseline XSPI was significantly predictive of all-cause (hazard ratio per 1 SD 1.4, 95% confidence interval 1.15-1.70, P=0.0006) and cardiovascular mortalities (1.47, 1.18-1.84, P=0.0006) after accounting for the covariates. The addition of XSPI to the base prognostic model significantly improved prediction of both all-cause mortality (net reclassification improvement=0.1549, P=0.0012) and cardiovascular mortality (net reclassification improvement=0.1535, P=0.0033). XSPI was superior to carotid-pulse wave velocity, forward and backward wave amplitudes, and left ventricular ejection fraction in consideration of overall independent and incremental prognostics values.

CONCLUSIONS

In end-stage renal disease patients undergoing regular hemodialysis, XSPI was significantly predictive of long-term mortality and demonstrated an incremental value to conventional prognostic factors.

Chronic Kidney Disease and Disproportionally Increased Cardiovascular Damage: Does Oxidative Stress Explain the Burden?

Chronic kidney disease (CKD) patients are among the groups at the highest risk for cardiovascular disease and significantly shortened remaining lifespan. CKD enhances oxidative stress in the organism with ensuing cardiovascular damage. Oxidative stress in uremia is the consequence of higher reactive oxygen species (ROS) production, whereas attenuated clearance of pro-oxidant substances and impaired antioxidant defenses play a complementary role. The pathophysiological mechanism underlying the increased ROS production in CKD is at least partly mediated by upregulation of the intrarenal angiotensin system. Enhanced oxidative stress in the setting of the uremic milieu promotes enzymatic modification of circulating lipids and lipoproteins, protein carbamylation, endothelial dysfunction via disruption of nitric oxide (NO) pathways, and activation of inflammation, thus accelerating atherosclerosis. Left ventricular hypertrophy (LVH) and heart failure are hallmarks of CKD. NADPH oxidase activation, xanthine oxidase, mitochondrial dysfunction, and NO-ROS are the main oxidative pathways leading to LVH and the cardiorenal syndrome. Finally, a subset of antioxidant enzymes, the paraoxonases (PON), deserves special attention due to abundant clinical evidence accumulated regarding reduced serum PON1 activity in CKD as a contributor to the increased burden of cardiovascular disease. Future, meticulously designed studies are needed to assess the effects of antioxidant therapy on patients with CKD.

Global kidney health 2017 and beyond: a roadmap for closing gaps in care, research, and policy

The global nephrology community recognises the need for a cohesive plan to address the problem of chronic kidney disease (CKD). In July, 2016, the International Society of Nephrology hosted a CKD summit of more than 85 people with diverse expertise and professional backgrounds from around the globe. The purpose was to identify and prioritise key activities for the next 5-10 years in the domains of clinical care, research, and advocacy and to create an action plan and performance framework based on ten themes: strengthen CKD surveillance; tackle major risk factors for CKD; reduce acute kidney injury-a special risk factor for CKD; enhance understanding of the genetic causes of CKD; establish better diagnostic methods in CKD; improve understanding of the natural course of CKD; assess and implement established treatment options in patients with CKD; improve management of symptoms and complications of CKD; develop novel therapeutic interventions to slow CKD progression and reduce CKD complications; and increase the quantity and quality of clinical trials in CKD. Each group produced a prioritised list of goals, activities, and a set of key deliverable objectives for each of the themes. The intended users of this action plan are clinicians, patients, scientists, industry partners, governments, and advocacy organisations. Implementation of this integrated comprehensive plan will benefit people who are at risk for or affected by CKD worldwide.

Albuminuria and Endothelial Dysfunction in Patients with Non-Diabetic Chronic Kidney Disease

BACKGROUND Albuminuria has been associated with cardiovascular events, but whether such an association can be explained by endothelial dysfunction is not fully understood. In this study, we examined the relationship between the urine albumin-to-creatinine ratio (UACR) and biomarkers of endothelial function in patients with chronic kidney disease (CKD). MATERIAL AND METHODS The cross-sectional associations of renal dysfunction and UACR with procoagulant and inflammatory factors were evaluated for 151 consecutive CKD (stage 3-5) patients. Subjects were grouped by UACR (≤300 mg/g or >300 mg/g) and estimated glomerular filtration rate (eGFR) (30≤ eGFR <60, 15≤ eGFR <30, or eGFR <15 ml/min per 1.73 m²). RESULTS A higher UACR level was associated with an increase in von Willebrand factor antigen (vWF: Ag) levels, vWF activity, factor VIII, interleukin-2, and log (interleukin-6), even after adjustment for risk factors. Linear regression analysis indicated that for every 88.5 mg/g increase in UACR, the vWF activity and factor VIII were elevated by 8.3% and 6.3%, respectively. The factorial design ANOVA data showed no statistically significant interaction between UACR and CKD stage with procoagulant and inflammatory factors. CONCLUSIONS Our study shows an eGFR-independent association of higher UACR with elevations in markers of endothelial dysfunction and inflammatory factors in CKD patients.

In-Hospital Cardiovascular Complications After Pancreas Transplantation in the United States from 2003 to 2012

Large database studies detailing the risk of perioperative cardiovascular complications after pancreas transplant has been limited, perhaps because these outcomes are not captured by transplant registries. Greater data on the incidence and risks of such outcomes could provide additional insight for referring physicians and inform potential recipients of their risk. We performed a serial, cross-sectional analysis of the National Inpatient Sample, the largest publicly available inpatient database in the United States, to assess for the risk of cardiovascular complications after pancreas transplants in the United States from 2003 to 2012 (n = 13,399). Using multivariable logistic regression models, the risk of cardiovascular outcomes after simultaneous pancreas-kidney transplants (SPK) was compared with solitary pancreas transplants (pancreas after kidney and pancreas transplant alone [PAK + PTA]). The unadjusted prevalence of in-hospital cardiovascular complications was higher in SPK than PAK + PTA (5.5% vs 3.7%, p <0.001). After multivariable adjustment, SPK remained associated with significantly higher odds of any cardiovascular complication (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.21 to 1.80, p = 0.01), and particularly stroke (OR 13.41, 95% CI 4.78 to 37.63, p <0.001), compared with PAK + PTA. However, there was no difference in perioperative mortality (OR 0.78, 95% CI 0.54 to 1.12, p = 0.18). In conclusion, these findings highlight the association between uremia and stroke in pancreas transplant patients, as well as the need for improved preoperative cardiac risk assessment and perioperative management, especially in those who underwent SPK.

The nature, consequences, and management of neurological disorders in chronic kidney disease

Perhaps no other organ in the body is affected as often and in as many ways as the brain is in patients with chronic kidney disease (CKD). Several factors contribute to the neurological disorders in CKD including accumulation of uremic toxins, metabolic and hemodynamic disorders, oxidative stress, inflammation, and impaired blood brain barrier among others. The neurological disorders in CKD involve both peripheral and central nervous system. The peripheral neurological symptoms of CKD are due to somatic and cranial peripheral neuropathies as well as a myopathy. The central neurological symptoms of CKD are due to the cortical predominantly cortical, or subcortical lesions. Cognitive decline, encephalopathy, cortical myoclonus, asterixis and epileptic seizures are distinct features of the cortical disorders of CKD. Diffuse white matter disease due to ischemia and hypoxia may be an important cause of subcortical encephalopathy. A special and more benign form of subcortical disorder caused by brain edema in CKD is termed posterior reversible encephalopathy. Subcortical pathology especially when it affects the basal ganglia causes a number of movement disorders including Parkinsonism, chorea and dystonia. A stimulus-sensitive reflex myoclonus is believed to originate from the medullary structures. Sleep disorder and restless leg syndrome are common in CKD and have both central and peripheral origin. This article provides an overview of the available data on the nature, prevalence, pathophysiology, consequences and treatment of neurological complications of CKD.

CD133+ cells are associated with ADIPOCYTOKINES and endothelial dysfunction in hemodialysis patients

BACKGROUND

Hemodialysis (HD) patients have increased risk of cardiovascular disease (CVD). Impaired stem cell health and adipocytokine metabolism may play important roles in the complex pathophysiological mechanisms of CVD in this patient population. We aimed to investigate the relationships between CD133+ cell counts, adipocytokines and parameters of endothelial dysfunction and atherosclerosis in HD patients.

METHODS

In 58 chronic HD patients (male/female:28/30, mean age:58 ± 14 years), serum levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), leptin, adiponectin and resistin were measured by ELISA. Left ventricular mass index (LVMI), carotid intima-media thickness (CIMT), flow-mediated dilatation (FMD) of the brachial artery were measured. CD133+ cells were counted by flow cytometry (BD FACSCalibur-BD Bioscience,CA).

RESULTS

CD133+ cell counts were inversely associated with FMD (r = -0.39, p = 0.007) and positively correlated with serum resistin (r = 0.45, p < 0.001) and serum TNF-α (r = 0.31, p = 0.02). Serum leptin levels were higher in high CD133 group compared to low CD133 group [32.37(12.74-72.29) vs 15.50(5.38-37.12)ng/mL, p = 0.03]. Serum leptin levels were correlated with TNF-α(r = 0.35, p = 0.009). Serum adiponectin levels were negatively correlated with serum leptin (r = -0.28, p = 0.03). Serum resistin levels were associated with TNF-α (r = 0.54, p < 0.001) and leptin (r = 0.29, p = 0.03). Serum IL-6 levels were significantly associated with LVMI (r = 0.31, p = 0.03). Serum IL-6 levels were significantly higher in patients with carotid plaque compared to patients without plaque [12.75(9.91-28.68) vs 8.27(5.97-14.04) pg/mL, p = 0.02]. In multiple linear regression analysis to determine the factors predicting LogFMD; dialysis vintage, LVMI and LogCD133+ cell counts were included as independent variables(R = 0.57, adjusted R-square = 0.27, p = 0.001). CD133+ cell count and LVMI were found to significantly predict FMD (p = 0.03 and p = 0.04 respectively).

CONCLUSION

CD133+ cells were associated with inflammation and endothelial dysfunction in HD patients. Serum leptin, resistin and TNF-α levels were positively related to CD133+ cell count. Impaired regulation of undifferentiated stem cells and adipocytokines might contribute to endothelial dysfunction in HD patients.

IL-33 and ST2 levels in chronic kidney disease: Associations with inflammation, vascular abnormalities, cardiovascular events, and survival

Objective

Increased inflammation, associated with the increase in chronic kidney disease (CKD) stage, has a very important influence in vascular injury and cardiovascular diseases. In this study, we aimed to investigate the levels of IL-33 and ST2 in the different stages of CKD and to determine their effect on vascular damage and cardiovascular events (CVE).

Methods

This was an observational cohort study in which serum IL-33 and ST2 were obtained from 238 CKD (stages 1–5) patients. We examined the changes in IL-33/ST2 levels in CKD patients, as well as the association with a surrogate of endothelial dysfunction. Fatal and non-fatal CVE were recorded for a mean of 24 months. We also performed a COX regression analysis to determine the association of IL-33/ST2 levels with CVE and survival.

Results

IL-33 and ST2 levels were significantly increased and estimated glomerular filtration rates (eGFR) were decreased. Flow-mediated dilatation (FMD) was significantly decreased from stage 1 to stage 5 CKD. IL-33 and ST2 levels were associated with FMD, and ST2 was a predictor. Multivariate Cox analysis showed that the presence of diabetes mellitus, smoking, and proteinuria and haemoglobin, Hs-CRP, IL-33, and ST2 were associated with the risk of CVE. Kaplan-Meier survival curves showed that patients with IL-33 and ST2 levels below the median value (IL-33 = 132.6 ng/L, ST2 = 382.9 pg/mL) had a higher cumulative survival compared with patients who had IL-33 and ST2 levels above the median value (log-rank test, p = 0.000).

Conclusion

This is the first study that demonstrates that serum IL-33 and ST2 are associated with vascular injury, cardiovascular events, and survival in CKD patients.

Indoxyl sulfate (IS)-mediated immune dysfunction provokes endothelial damage in patients with end-stage renal disease (ESRD)

Progressive renal failure causes uremia-related immune dysfunction, which features a chronic inflammatory milieu. Given the central role of end-stage renal disease (ESRD)-related immune dysfunction in the pathogenesis of cardiovascular diseases (CVDs), much attention has been focused on how uremic toxins affect cellular immunity and the mechanisms underlying pathogenesis of atherosclerosis in ESRD patients. Here, we investigated the characteristics of monocytes and CD4+ T cells in ESRD patients and the immune responses induced by indoxyl sulfate (IS), a key uremic toxin, in order to explore the pathogenic effects of these cells on vascular endothelial cells. In ESRD patients, monocytes respond to IS through the aryl hydrocarbon receptor (AhR) and consequently produce increased levels of TNF-α. Upon stimulation with TNF-α, human vascular endothelial cells produce copious amounts of CX3CL1, a chemokine ligand of CX3CR1 that is highly expressed on CD4+CD28-T cells, the predominantly expanded cell type in ESRD patients. A migration assay showed that CD4+CD28- T cells were preferentially recruited by CX3CL1. Moreover, activated CD4+CD28- T cells exhibited cytotoxic capability allowing for the induction of apoptosis in HUVECs. Our findings suggest that in ESRD, IS-mediated immune dysfunction may cause vascular endothelial cell damage and thus, this toxin plays a pivotal role in the pathogenesis of CVD.

Association of adipokines with blood pressure, arterial elasticity and cardiac markers in dialysis patients: cross-sectional analysis of baseline data from a cohort study

Background

Adipokines are a set of cytokines secreted by white adipose tissue that have been suggested to be involved in the development of cardiovascular diseases. We aimed to evaluate the cross-sectional associations of a panel of representative adipokines with cardiovascular measures in a cohort of hemodialysis patients.

Methods

We measured plasma adiponectin, resistin, plasminogen activator inhibitor-1 (PAI-1), leptin, monocyte chemotactic protein 1 (MCP-1) and adipsin levels in 366 dialysis patients and 60 healthy controls. The associations of these adipokines with systolic blood pressure (assessed by ambulatory blood pressure monitoring), pulse wave velocity (PWV) and cardiac markers (BNP, NT-proBNP, Troponin I, Troponin T) in these patients were determined by general linear models with stepwise adjustment for covariates.

Results

In unadjusted comparison with controls, dialysis patients showed increased adiponectin, resistin, MCP-1 and adipsin levels, decreased PAI-1 concentrations (all p <0.001) and similar leptin levels (p = 0.82). On adjustment for body mass index and diabetes, however, the PAI-1 level was comparable between group (p = 0.06), whereas leptin levels became significantly higher in the patients(p <0.001). Higher adiponectin, lower PAI-1 and leptin levels were associated with higher systolic blood pressure, even after extensive adjustment (all p ≤ 0.01). Adiponectin was also consistently and inversely associated with PWV in fully adjusted models (p = 0.003). Resistin, PAI-1, leptin and adipsin showed negative associations with one or more circulating cardiac markers (all p ≤ 0.02).

Conclusions

We found significant associations between adipokines and cardiovascular measures. Our data suggest the possible involvement of adipokines in cardiovascular modulation in dialysis patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-017-0185-3) contains supplementary material, which is available to authorized users.

Sodium fluoride induces hypertension and cardiac complications through generation of reactive oxygen species and activation of nuclear factor kappa beta

Human exposure to sodium fluoride through its daily usage is almost inevitable. Cardiovascular and renal dysfunction has been associated with fluoride toxicity. Therefore, this study investigated the mechanism of action of sodium fluoride (NaF) induced hypertension and cardiovascular complications Forty male albino rats of an average of 10 rats per group were used. Group A received clean tap water. Toxicity was induced in Group B to D by administering graded doses of NaF through drinking water ad libitum for 10 days at 150 ppm, 300 ppm, and 600 ppm concentration respectively. Following administration of NaF, there was significant increase in systolic pressure, diastolic pressure and mean arterial pressure. Markers of oxidative stress; malondialdehyde, hydrogen peroxide, advance oxidation protein products, and protein carbonyl were significantly increased in dose-dependent pattern in the cardiac and renal tissues of rats together with significant decrease in the GST activity in NaF-treated rats compared to the control. Also serum markers of inflammation, cardiac, and renal damage including myeloperoxidase, xanthine oxidase, blood urea nitrogen, creatinine, Lactate dehydrogenase (LDH), and Creatinine kinase myocardial band (CK-MB) significantly increased indicating induction of oxidative stress, renal, and cardiac damage after exposure. Histopathology of the kidney and heart revealed aberrations in the histological architecture in NaF-treated rats. Also, immunohistochemistry showed higher expression of nuclear factor kappa beta (NF-kB) in the cardiac and renal tissues of rats administered NaF. Combining all, these results indicate NaF-induced hypertension through generation of reactive oxygen species and activation of renal and cardiac NF-kB expressions. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1089-1101, 2017.

Unrecognized Fibrinogen A α-Chain Amyloidosis: Results From Targeted Genetic Testing

BACKGROUND

Fibrinogen A α-chain (AFib) amyloidosis results from autosomal-dominant mutations in the gene encoding AFib (FGA). Patients with this disorder typically present with proteinuria. Isolated cases of AFib amyloidosis, carrying the FGA p.Glu545Val variant, were identified in the district of Braga, in northwest Portugal. This observation led us to hypothesize that this disorder might be an unrecognized cause of kidney disease in that region and prompted us to carry out targeted genetic testing for the p.Glu545Val variant in the local hemodialysis population and family members of identified cases.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

3 groups of participants: (1) kidney biopsy registry, n=4; (2) hemodialysis facility, n=122 of 267 patients; and (3) genetically at-risk individuals; n=69 of 167 family members.

OUTCOMES

Kidney disease, kidney disease progression, and survival.

RESULTS

The p.Glu545Val variant was identified in all 4 patients of the biopsy registry, 12 of 122 (9.8%) hemodialysis patients tested, and 34 of 69 (49%) relatives tested. These 50 cases belonged to 13 unrelated families with kidney disease or amyloidosis identified in 61% of probands. 35 individuals presented with hypertension at a mean of 51.0±10.4 years. Of these, 30 developed kidney disease at a mean of 56.7±12.0 years, and 21 initiated dialysis therapy at a mean of 61.4±11.3 years. Heart, liver, spleen, colon, and ileum were involved along the progression of the disease. Kidney disease was formerly attributed to hypertension in 25% of patients with AFib amyloidosis undergoing hemodialysis.

LIMITATIONS

Retrospective data collection for patients with amyloidosis previously diagnosed.

CONCLUSIONS

AFib amyloidosis appears to be an under-recognized disorder in Braga, Portugal, where we found a high frequency of the FGA p.Glu545Val variant. Due to the nonspecific nature of its major clinical features, the diagnosis of AFib amyloidosis should have a high index of suspicion, particularly in populations in which hypertension is prevalent.

Inflammatory and Metabolic Syndrome Biomarker Analysis of Vascular Outcomes in End-stage Renal Disease

End-stage renal disease (ESRD) presents a complex syndrome in which inflammatory and metabolic processes contribute to disease progression and development of comorbid conditions. Over $1 trillion is spent globally on ESRD care. Plasma samples collected from 83 ESRD patients prior to hemodialysis were profiled for metabolic and inflammatory biomarker concentrations. Concentrations were compared between groups with and without history of stroke, acute coronary syndrome (ACS), congestive heart failure (CHF), and coronary artery disease (CAD). The 25 patients (30.1%) with history of stroke demonstrated decreased plasma interferon-γ levels (p = 0.042) and elevated plasma resistin, interleukin (IL)-1α, and leptin levels (p = 0.008, 0.021, 0.026, respectively) when compared with ESRD patients without history of stroke. The 14 patients (16.9%) with history of ACS demonstrated elevated plasma IL-6 levels (p = 0.040) when compared with ESRD patients without history of ACS. The 30 patients (36.1%) with history of CHF demonstrated decreased plasma leptin levels (p = 0.031) and elevated plasma IL-1β levels (p = 0.042) when compared with ESRD patients without history of CHF. Finally, the 39 patients (47.0%) with history of CAD demonstrated elevated plasma IL-1α levels (p = 0.049) when compared with ESRD patients without history of CAD. Plasma biomarker concentration disturbances were observed in ESRD patients with history of stroke, ACS, CHF, and CAD when compared with ESRD patients without such history. Proinflammatory biomarker elevations were seen in stroke, ACS, CHF and CAD, while adipocytokine aberrations were observed in both stroke and CHF. These studies demonstrate that biomarker profiling of vascular comorbidities in ESRD may provide useful diagnostic and prognostic information in the management of ESRD patients.

Targeting Immunity in End-Stage Renal Disease

BACKGROUND

Despite the stable incidence of end-stage renal disease (ESRD), it continues to be associated with an unacceptably high cardiovascular risk.

SUMMARY

ESRD is characterized by enhanced oxidative stress and severe inflammation, which boost cardiovascular risk, thus increasing cardiovascular-associated mortality rate. While substantial effort has been made in the technological innovation of dialytic techniques, few significant advances have been made to reduce inflammation in patients with ESRD. Indeed, this contrasts with the extensive scientific breakthroughs made in the basic field of science in targeting inflammation. There is thus a pressing need for clinical trials to test the effect of reducing inflammation in patients with ESRD. Here, we will revisit the negative effect of ESRD on inflammation and explore the impact of enhanced inflammation on cardiovascular outcomes and survival in patients with ESRD. Finally, we will discuss the need for clinical trials that target inflammation in ESRD, as well as weigh potential disadvantages and offer novel innovative approaches. Key Message: We will try to understand why the issue of inflammation has not been successfully addressed thus far in patients with ESRD, while at the same time weighing the potential disadvantages and offering novel innovative approaches for targeting inflammation in patients with ESRD.

High Neutrophil-to-Lymphocyte Ratio Predicts Cardiovascular Mortality in Chronic Hemodialysis Patients

The neutrophil-to-lymphocyte ratio (NLR) is a novel simple biomarker of inflammation. It has emerged as a predictor of poor prognosis in cancer and cardiovascular disease in general population. But little was known of its prognostic value in chronic hemodialysis (HD) patients. Here we investigated the association between NLR and cardiovascular risk markers, including increased pulse pressure (PP), left ventricular mass index (LVMI) and intima-media thickness (IMT), and mortality in HD patients. Two hundred and sixty-eight HD patients were enrolled in this study and were followed for 36 months. The primary end point was all-cause mortality and cardiovascular mortality. Multivariable Cox regression was used to calculate the adjusted hazard ratios for NLR on all-cause and cardiovascular survival. We pinpointed that higher NLR in HD patients was a predictor of increased PP, LVMI, and IMT; HD patients with higher NLR had a lower survival at the end of the study; furthermore, high NLR was an independent predictor of all-cause and cardiovascular mortality when adjusted for other risk factors. In conclusion, higher NLR in HD patients was associated with cardiovascular risk factors and mortality.

Use of Electronic Health Data to Estimate Heart Failure Events in a Population-Based Cohort with CKD

BACKGROUND AND OBJECTIVES

Studies that use electronic health data typically identify heart failure (HF) events from hospitalizations with a principal diagnosis of HF. This approach may underestimate the total burden of HF among persons with CKD. We assessed the accuracy of algorithms for identifying validated HF events from hospitalizations and outpatient encounters, and we used this validation information to estimate the rate of HF events in a large CKD population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We identified a cohort of 15,141 adults age 18-89 years with an eGFR<60 ml/min per 1.73 m2 from 2008 to 2011. Potential HF events during follow-up were randomly sampled for validation with medical record review. Positive predictive values from the validation study were used to estimate the rate of validated HF events in the full cohort.

RESULTS

A total of 1864 participants had at least one health care encounter that qualified as a potential HF event during 2.7 years of mean follow-up. Among 313 potential events that were randomly sampled for validation, positive predictive values were 92% for hospitalizations with a principal diagnosis of HF, 32% for hospitalizations with a secondary diagnosis of HF, and 70% for qualifying outpatient HF encounters. Through use of this validation information in the full cohort, the rate of validated HF events estimated from the most comprehensive algorithm that included principal and secondary diagnosis hospitalizations and outpatient encounters was 35.2 events/1000 person-years (95% confidence interval, 33.1 to 37.4), compared with 9.5 events/1000 person-years (95% confidence interval, 8.7 to 10.5) from the algorithm that included only principal diagnosis hospitalizations. Outpatient encounters accounted for 20% of the total number of validated HF events.

CONCLUSIONS

In studies that rely on electronic health data, algorithms that include hospitalizations with a secondary diagnosis of HF and outpatient HF encounters more fully capture the burden of HF, although validation of HF events may be necessary with this approach.