Elevated interleukin-6 predicts progressive carotid artery atherosclerosis in dialysis patients: association with Chlamydia pneumoniae seropositivity

Exploring the Associations Between Inflammatory Biomarkers, Survival, and Cardiovascular Events in Hemodialysis Patients and the Interrelationship with Nutritional Parameters-The Experience of a Single Transylvanian Dialysis Center

Background/Objectives: In hemodialysis (HD), inflammatory biomarkers are discussed as prognostic markers for survival and cardiovascular events (CVEs). The results of the studies are not uniform and there are particularities related to population groups and comorbidities. In addition, it is known that inflammation determines protein malnutrition and less about the effect of adipose tissue on inflammation in HD. This study investigates the relationship between inflammatory molecules and nutritional biomarkers, and CVE and survival in HD patients. Methods: We included, in an observational, longitudinal study, 65 patients with chronic HD (53 without diabetes and 22 smokers), with a mean age of 60.1 ± 12.4 years. High-sensitivity C-reactive protein (hs-CRP), interleukin 1 beta, tumor necrosis factor alpha (TNF-alpha), interleukin 6, soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK), soluble CD163 (sCD163), and fibroblast growth factor 21 were determined. We recorded survival and cardiovascular events for 60 months. Univariate and multivariate analyses were performed. Results: Hs-CRP was significantly associated with survival (p = 0.014) in the total group. In smokers and former smokers, TNF-α lower than 368.34 pg/mL was associated with better survival. In multivariate analysis, hs-CRP was correlated with adipose tissue biomarkers (p = 0.006), and sCD163 was correlated with total and LDL cholesterol (p = 0.002). In addition, in univariate analysis, sTWEAK was correlated with serum albumin (p = 0.026, r = -0.30). In conclusion, in HD patients, hs-CRP was significantly associated with survival, and low TNF-alpha values in smokers and former smokers were linked to better survival. Hs-CRP was also correlated with adipose tissue biomarkers, CD163 was correlated with total and LDL cholesterol, and albumin was inversely associated with sTWEAK. The relation between inflammatory molecules and adipose tissue biomarkers was less identified in HD patients until now.

The cardiovascular unphysiology of thrice weekly hemodialysis

PURPOSE OF REVIEW

This review examines the unphysiological nature of conventional intermittent hemodialysis (IHD) and explores alternative dialysis modalities that more closely mimic natural kidney function. As cardiovascular complications remain a leading cause of morbidity and mortality in dialysis patients, understanding and addressing the limitations of IHD is crucial for improving outcomes.

RECENT FINDINGS

IHD's intermittent nature leads to significant fluctuations in metabolites, electrolytes, and fluid status, contributing to hemodynamic instability and increased cardiovascular risk. More frequent dialysis modalities, such as short daily hemodialysis and nocturnal hemodialysis have numerous benefits including reduced left ventricular hypertrophy, improved blood pressure control, and potentially decreasing mortality. Peritoneal dialysis offers a more continuous approach to treatment, which may provide cardiovascular benefits through gentler fluid removal and residual kidney function preservation.

SUMMARY

Conventional thrice weekly intermittent hemodialysis offers a fundamentally unphysiologic equilibrium of uremic solutes. Alternate approaches have demonstrated cardiovascular benefits.

Inflammation and all-cause mortality in patients undergoing peritoneal dialysis

OBJECTIVE

This study aimed to evaluate inflammatory biomarkers in patients undergoing peritoneal dialysis and investigate their association with all-cause mortality or transfer to hemodialysis.

METHODS

This prospective cohort study included 43 patients undergoing peritoneal dialysis. Plasma levels of cytokines were measured using flow cytometry and capture enzyme-linked immunosorbent assay. Biomarkers were categorized based on their respective median values. Survival analysis was conducted using the Kaplan-Meier estimator, considering two outcomes: all-cause mortality and transfer to hemodialysis.

RESULTS

After adjusting for confounding factors, plasma levels above the median of the levels of CCL2 and plasma, as well as below the median of TNF-α, and the median of dialysate IL-17 levels, were associated with an increased risk of experiencing the specified outcomes after approximately 16 months of follow-up.

CONCLUSION

These findings suggest that inflammatory biomarkers may be a valuable tool for predicting all-cause mortality and transfer to hemodialysis in patients undergoing peritoneal dialysis.

Cardiovascular Calcifications Are Correlated with Inflammation in Hemodialysis Patients

Background and Objectives: The main cause of morbidity and mortality in hemodialysis patients is cardiovascular disease, which is quite common. The main objective of our study was to investigate the relationship between oxidative stress, inflammation, and vascular and valvular calcifications in hemodialysis patients. Materials and Methods: This observational study had 54 hemodialysis patients, with an average age of 60.46 ± 13.18 years. Cardiovascular ultrasound was used to detect and/or measure aortic and mitral valve calcifications, carotid and femoral atheroma plaques, and common carotid intima-media thickness. The aortic calcification score was determined using a lateral abdomen plain radiograph. The inflammatory, oxidative, metabolic, and dietary statuses, as well as demographic characteristics, were identified. Results: There were significant correlations between the levels of IL-6 and carotid plaque number (p = 0.003), fibrinogen level and aortic valve calcifications (p = 0.05), intima-media thickness (p = 0.0007), carotid plaque number (p = 0.035), femoral plaque number (p = 0.00014), and aortic calcifications score (p = 0.0079). Aortic annulus calcifications (p = 0.03) and intima-media thickness (p = 0.038) were adversely linked with TNF-α. Nutrition parameters were negatively correlated with atherosclerosis markers: number of carotid plaques with albumin (p = 0.013), body mass index (p = 0.039), and triglycerides (p = 0.021); number of femoral plaques with phosphorus (0.013), aortic calcifications score with albumin (p = 0.051), intima-media thickness with LDL-cholesterol (p = 0.042). Age and the quantity of carotid plaques, femoral plaques, and aortic calcifications were linked with each other (p = 0.0022, 0.00011, and 0.036, respectively). Aortic annulus calcifications (p = 0.011), aortic valve calcifications (p = 0.023), and mitral valve calcifications (p = 0.018) were all associated with an increased risk of death. Conclusions: Imaging measures of atherosclerosis are adversely connected with dietary status and positively correlated with markers of inflammation and risk of mortality.

Plasma Interleukin-6 Level Predicts the Risk of Arteriovenous Fistula Dysfunction in Patients Undergoing Maintenance Hemodialysis

Systemic inflammation has been proposed as a relevant factor of vascular remodeling and dysfunction. We aimed to identify circulating inflammatory biomarkers that could predict future arteriovenous fistula (AVF) dysfunction in patients undergoing hemodialysis. A total of 282 hemodialysis patients were enrolled in this prospective multicenter cohort study. Plasma cytokine levels were measured at the time of data collection. The primary outcome was the occurrence of AVF stenosis and/or thrombosis requiring percutaneous transluminal angioplasty or surgery within the first year of enrollment. AVF dysfunction occurred in 38 (13.5%) patients during the study period. Plasma interleukin-6 (IL-6) levels were significantly higher in patients with AVF dysfunction than those without. Diabetes mellitus, low systolic blood pressure, and statin use were also associated with AVF dysfunction. The cumulative event rate of AVF dysfunction was the highest in IL-6 tertile 3 (p = 0.05), and patients in tertile 3 were independently associated with an increased risk of AVF dysfunction after multivariable adjustments (adjusted hazard ratio = 3.06, p = 0.015). In conclusion, circulating IL-6 levels are positively associated with the occurrence of incident AVF dysfunction in hemodialysis patients. Our data suggest that IL-6 may help clinicians identify those at high risk of impending AVF failure.

A randomized controlled pilot trial of anakinra for hemodialysis inflammation

Chronic inflammation is highly prevalent among patients receiving maintenance hemodialysis and is associated with morbidity and mortality. Inhibiting inflammation with anti-cytokine therapy has been proposed but not well studied in this population. Therefore, we conducted the ACTION trial, a pilot, multicenter, randomized, placebo-controlled trial of an IL-1 receptor antagonist, anakinra, to evaluate safety, tolerability, and feasibility, and explore efficacy. Eighty hemodialysis patients with plasma concentrations of high sensitivity C-reactive protein (hsCRP) 2 mg/L and above were randomized 1:1 to placebo or anakinra 100 mg, three times per week via the hemodialysis circuit for 24 weeks, with an additional 24 weeks of post-treatment safety monitoring. Efficacy outcomes included changes in hsCRP (primary), cytokines, and patient-reported outcomes. Rates of serious adverse events and deaths were similar with anakinra and placebo (serious adverse events: 2.71 vs 2.74 events/patient-year; deaths: 0.12 vs 0.22 events/patient-year). The rate of adverse events of interest (including infections and cytopenias) was significantly lower with anakinra than placebo (0.48 vs 1.40 events/patient-year). Feasibility was demonstrated by attaining the enrollment target, a retention rate of 80%, and administration of 72% of doses. The median decrease in hsCRP from baseline to Week 24 was 41% in the anakinra group and 6% in the placebo group, a between-group difference that was not statistically significant. For IL-6, the median decreases were significant: 25% and 0% in the anakinra and placebo groups, respectively. An effect of anakinra on patient-reported outcomes was not evident. Thus, anakinra was well tolerated and did not increase infections or cytopenias. The promising safety data and potential efficacy on CRP and IL-6 provide support for conducting definitive trials of IL-1 inhibition to improve outcomes in hemodialysis patients.

Evolving Concepts on Inflammatory Biomarkers and Malnutrition in Chronic Kidney Disease

While patient care, kidney replacement therapy, and transplantation techniques for chronic kidney disease (CKD) have continued to progress, the incidence of malnutrition disorders in CKD appears to have remained unchanged over time. However, there is now a better understanding of the underlying pathophysiology according to the disease background, disease stage, and the treatment received. In CKD patients, the increased production of proinflammatory cytokines and oxidative stress lead to a proinflammatory milieu that is at least partially responsible for the increased morbidity and mortality in this patient population. New insights into the pathogenic role of innate immunity and the proinflammatory cytokine profile, characterized, for instance, by higher levels of IL-6 and TNF-α, explain some of the clinical and laboratory abnormalities observed in these patients. In this article, we will explore currently available nutritional-inflammatory biomarkers in distinct CKD populations (hemodialysis, peritoneal dialysis, transplantation) with a view to evaluating their efficacy as predictors of malnutrition and their involvement in the common proinflammatory process. Although there is a direct relationship between inflammatory-nutritional status, signs and symptoms [e.g., protein-energy wasting (PEW), anorexia], and comorbidities (e.g., atheromatosis, atherosclerosis), we are in need of clearly standardized markers for nutritional-inflammatory assessment to improve their performance and design appropriate bidirectional interventions.

Efficacy of medium cut-off dialyzers and comparison with high-flux dialyzers in patients on maintenance hemodialysis: A systematic review and meta-analysis

Medium cut‐off (MCO) dialyzers were designed to provide better clearance of uremic toxins. We conducted a meta‐analysis comparing MCO with high‐flux (HF) dialyzers for the effect on uremic toxins in maintenance hemodialysis (HD) patients. Five databases were systematically searched for relevant studies and nine studies were identified finally. Reduction ratio (RR) of urea, urea, creatinine, β2‐macroglobulin (β2‐MG), kappa free light chain (κFLC), and lambda FLC (λFLC) levels were not significantly different between MCO and HF dialyzers. But RR of β2‐MG, κFLC, and λFLC were greater for MCO than HF dialyzers. MCO dialyzers could better reduce tumor necrosis factor‐α (TNF‐α) levels. Subgroup analysis stratified by study design indicated that in randomized controlled trial (RCT) studies, albumin levels was lower in MCO than HF dialyzers group, but the two dialyzers treatments were equivalent in non‐RCT subgroup. Compared with HF dialyzers, MCO dialyzers provided higher middle‐molecules uremic toxins clearance and obviously reduced TNF‐α levels.

IL-6 Is Associated with Progression of Coronary Artery Calcification and Mortality in Incident Dialysis Patients

INTRODUCTION

Inflammation is important in the pathogenesis of atherosclerosis. Elevated interleukin-6 (IL-6) is associated with cardiovascular events and also predicts mortality in individuals with CKD. Our goal was to determine the association between IL-6, FGF23, and high-sensitivity C-reactive protein (hsCRP) on coronary artery calcification (CAC) progression and mortality in incident dialysis patients without prior coronary events.

METHODS

A prospective cohort of incident adult dialysis participants had CAC measured by ECG-triggered multislice CT scans at baseline and at least 12 months later. Lipids, mineral metabolism markers, FGF23, and inflammatory markers, such as IL-6 and hsCRP, were measured at the baseline visit.

RESULTS

Participants in the high IL-6 tertile had the highest baseline CAC score (133.25 [10.35-466.15]) compared to the low (0.25 [0-212.2]) and intermediate (29.55 [0-182.85]) tertiles. Almost half of the participants with high IL-6 (15 of 32 [46.9%]) experienced progression of CAC compared to participants with low (8 of 32 [25%]) and intermediate (9 of 32 [28.1%]) (p = 0.05) IL-6 levels. Each log increase in IL-6 was associated with increase in death (hazard ratio 2.2, 95% CI: 1.2-3.8; p = 0.01). After adjusting for smoking, age, gender, race, diabetes, phosphate, and baseline calcium score, IL-6 (log) was associated with 2.2 times (95% CI: 1.1-4.6; p = 0.03) increase in death.

CONCLUSION

IL-6 is associated with progression of CAC and mortality in incident dialysis patients.

The association of Chlamydia pneumoniae infection with atherosclerosis: Review and update of in vitro and animal studies

Previous studies have tended to relate Chlamydia pneumoniae (Cpn) infection to atherosclerosis. However, while serological studies have mostly reinforced this hypothesis, inconsistent and even contradictory findings have been reported in various researches. Recent papers have pointed to the significance of Cpn in atherosclerotic lesions, which are regarded as the initiator and cause of chronic inflammation. This bacterium develops atherosclerosis by phenotypic changes in vascular smooth muscle cells, dysregulation of endothelin-1 in the vascular wall, and releasing pro-inflammatory cytokines from Toll-like receptor-2 (TLR2). Furthermore, Cpn infection, particularly under hyperlipidemic conditions, enhances monocyte adhesion to endothelium; changes the physiology of the host, e.g., cholesterol homeostasis; and activates the Low-density lipoprotein (LDL) receptor, which is the initial step in atherogenesis. On the other hand, it has been reported that Cpn, even without the immune system of the host, has the ability to stimulate arterial thickening. Moreover, there is evidence that Cpn can increase the impact of the classical risk factors such as hyperlipidemia, pro-inflammatory cytokines, and smoking for atherosclerosis. Furthermore, animal studies have shown that Cpn infection can induce atherosclerotic, which alongside hyperlipidemia is a co-risk factor for cardiovascular disease. Although the exact link between Cpn and atherosclerosis has not been determined yet, previous studies have reported possible mechanisms of pathogenesis for this bacterium. Accordingly, investigating the exact role of this infection in causing atherosclerosis may be helpful in controlling the disease.

Role of Uremic Toxins in Early Vascular Ageing and Calcification

In patients with advanced chronic kidney disease (CKD), the accumulation of uremic toxins, caused by a combination of decreased excretion secondary to reduced kidney function and increased generation secondary to aberrant expression of metabolite genes, interferes with different biological functions of cells and organs, contributing to a state of chronic inflammation and other adverse biologic effects that may cause tissue damage. Several uremic toxins have been implicated in severe vascular smooth muscle cells (VSMCs) changes and other alterations leading to vascular calcification (VC) and early vascular ageing (EVA). The above mentioned are predominant clinical features of patients with CKD, contributing to their exceptionally high cardiovascular mortality. Herein, we present an update on pathophysiological processes and mediators underlying VC and EVA induced by uremic toxins. Moreover, we discuss their clinical impact, and possible therapeutic targets aiming at preventing or ameliorating the harmful effects of uremic toxins on the vasculature.

Hospital costs and prognosis in end-stage renal disease patients receiving coronary artery bypass grafting

Background

Coronary artery disease is common in patients with end-stage renal disease (ESRD). Patients with ESRD are a high-risk group for cardiac surgery and have increased morbidity and mortality. Most studies comparing ESRD patients receiving coronary artery bypass grafting (CABG) or percutaneous coronary intervention have found that the long-term survival is good in ESRD patients after CABG. The aim of our study was to compare ESRD patients who underwent CABG with the general population who underwent CABG, in terms of prognosis and hospital costs.

Methods

This study analyzed data from the National Health Insurance Research Database in Taiwan for patients who were diagnosed with ESRD and received CABG (ICD-9-CM codes 585 or 586) between January 1, 2004, and December 31, 2009. The ESRD patients included in this study all received catastrophic illness cards with the major illness listed as ESRD from the Ministry of Health and Welfare in Taiwan.

The control subjects were randomly selected patients without ESRD after propensity score matching with ESRD patients according to age, gender, and comorbidities at a 2:1 ratio from the same dataset.

Results

A total of 48 ESRD patients received CABG, and their mean age was 62.04 ± 10.04 years. Of these patients, 29.2% were aged ≥70 years, and 66.7% were male. ESRD patients had marginally higher intensive care unit (ICU) stays (11.06 vs 7.24 days) and significantly higher ICU costs (28,750 vs 17,990 New Taiwan Dollars (NTD)) than non-ESRD patients. Similarly, ESRD patients had significantly higher surgical costs (565,200 vs. 421,890 NTD), a higher perioperative mortality proportion (10.4% vs 2.1%) and a higher postoperative mortality proportion (33.3% vs 11.5%) than non-ESRD patients.

Conclusions

After CABG, ESRD patients had a higher risk of mortality than non-ESRD patients, and ICU and surgery costs were also higher among the ESRD patients than among patients without ESRD.

C-Reactive Protein and Anti-Chlamydia Pneumoniae Antibodies as Risk Factors of Cardiovascular Death in Incident Patients on Peritoneal Dialysis

Objective

Recently it has been pointed out that inflammation and infections caused by germs such as Chlamydia pneumoniae are independent cardiovascular risk factors for the general population, but information about these relationships in dialysis patients is scarce. This work was done to analyze the association of C-reactive protein (CRP) and IgG anti- Chlamydia pneumoniae antibodies (anti-Chlp-IgG) as independent cardiovascular risk factors in incident patients on continuous ambulatory peritoneal dialysis (CAPD).

Design

Single-cohort, prospective observational study.

Setting

Three CAPD centers from the Instituto Mexicano del Seguro Social, and one from the Instituto de Seguridad y Servicios Sociales de los Trabajadores del Estado, Mexico.

Patients

A cohort of 75 adult incident patients on CAPD, without clinical signs of congestive heart failure, coronary heart disease, or peripheral arterial insufficiency. No restrictions for age, gender, or cause of renal failure were applied.

Primary Outcome

Mortality.

Methods

Demographic variables, body composition by electrical bioimpedance, serum glucose, urea, creatinine, lipids, homocysteine, nutritional markers (albumin, prealbumin, and transferrin), CRP, and anti-Chlp-IgG were measured and registered at the time of the first admission. When a patient died, the cause of death was determined by review of the clinical chart.

Results

Mean follow-up time was 10.25 patient-months. There were 14 cardiovascular deaths. CRP was positive (> 10 mg/L) in 64% of the patients, and anti-Chlp-IgG in 64%; 29% of the patients were positive for both markers. The relative risk for cardiovascular mortality was 6.23 for patients positive for either CRP or anti-Chlp-IgG, and increased to 9.52 when both markers were positive. Multivariate analysis revealed that CRP and anti-Chlp-IgG were stronger cardiovascular death predictors than age, diabetes, and nutritional status.

Conclusion

These data suggest that inflammation and the presence of Chlamydia pneumoniae infections are important predictors of cardiovascular death in patients on CAPD.

Prognostic Significance of Serum Lactic Acid, Lactate Dehydrogenase, and Albumin Levels in Patients with Metastatic Colorectal Cancer

Aim

To identify the population of patients with high risk of distant metastasis and the poor prognosis before treatment, so as to provide early intervention and better treatment decision.

Method

69 patients with nonmetastatic colorectal cancer (non-mCRC) and 57 with metastatic CRC (mCRC) were enrolled to evaluate the prognostic value of serum albumin (ALB), serum lactate (SLA), and lactate dehydrogenase (LDH) in patients with metastatic CRC. We then followed up the 57 patients with mCRC. The T test, Chi square test, Kaplan-Meier survival analysis model, and Multivariate Cox proportional hazards regression model were applied to assess the prognostic significance of SLA, LDH, and serum ALB on the patients with mCRC.

Results

Compared with the non-mCRC group, the patients with mCRC had an elevated level of blood lactate (P=0.01) and LDH (P<0.01) and a reduced level of ALB (P<0.01). Multivariable analysis showed the elevated LDH combined with elevated SLA (HR=2.922, 95%CI=0.971-8.793, P=0.056), the reduced ALB (HR=0.417, 95%CI=0.230-0.754, P=0.004), and the elevated CA199 (HR=2.072, 95%CI=1.125-3.816, P=0.019) were independent prognostic factors for PFS of patients with mCRC. The elevated LDH (HR=2.204, 95%CI=1.000-4.858, P=0.050), reduced ALB (HR=0.459, 95%CI=0.236-0.892, P=0.022), elevated LDH combined with elevated SLA (HR=3.187, 95%CI=1.019-9.970, P=0.046), and the primary site of tumor (HR=0.359, 95%CI=0.174-0.740, P=0.006) were independent prognostic factors for OS of patients with mCRC.

Conclusions

Taken together, our results implicate that the elevated LDH combined with elevated SLA and the reduced ALB are prognostic indicators for patients with mCRC.

Impact of arteriovenous fistula blood flow on serum il-6, cardiovascular events and death: An ambispective cohort analysis of 64 Chinese hemodialysis patients

Flows (Qa) of arteriovenous fistula (AVF) impact the dialysis adequacy in hemodialysis (HD) patients. However, data for different access flow levels on outcomes related to long-term dialysis patients, especially in Chinese patients, are limited. Herein, we performed an ambispective, mono-centric cohort study investigating the association between the AVF flows and inflammation, cardiovascular events and deaths in Chinese hemodialysis patients bearing a radio-cephalic fistula (AVF) from 2009 to 2015. Twenty-three patients (35.9%) developed at least one episode of cardiovascular disease (CVD) in two years after AVF creation. AVF Qa, IL-6 and hsCRP were significantly higher in patients with CVD than in patients without CVD. Multi-factorial binary logistic regression analysis found that the independent and strongest risk factor for CVD in HD patients was serum IL-6, which showed a positive association with AVF Qa levels in patients. Therefore, the linkage between AVF Qa tertiles and adverse clinical outcomes (cardiovascular events and mortality) was examined over a median follow-up of five years. IL-6 was significantly increased in the high AVF Qa (>1027.13 ml/min) group. Patients with median AVF Qa showed the lowest morbidity and mortality of CVD according to the AVF Qa tertiles, whereas higher Qa was associated with a higher risk of CVD, and lower AVF Qa (600 ml/min ≤AVF Qa <821.12 ml/min) had a higher risk of non-CVD death. Therefore, keeping the AVF Qa at an optimal level (821.12 to 1027.13 ml/min) would benefit HD patients, improve long-term clinical outcomes and lower AVF-induced inflammation.

Association of inflammatory cytokines with mortality in peritoneal dialysis patients

Aims: Previous study on association between pro-inflammatory cytokines and mortality in PD population is limited. We aimed to investigate here.

Methods: Total 50 patients who underwent incident PD were enrolled in this study. We measured the titers of pro-inflammatory cytokines Interleukin-18(IL-18), Interleukin-6 (IL-6), and Interleukin-1ß (IL-1ß). Study outcomes were all-cause mortality, cardiovascular-related mortality, and infection-caused mortality. Cox-regression model was used.

Results: In this 7 year prospective study, IL-18 ≥ 804.3pg/ml, IL-6 ≥ 3.92 pg/ml, IL-1ß ≥ 0.86pg/ml, age ≥ 50 years-old, and existence of diabetes could be used as individual significant predictors for mortality in PD patients. Higher titers of IL-6 were associated with lower averaging albumin levels within 1^st year of PD. Increasing numbers of these risk markers of mortality was associated with decreasing survival advantages (P = 0.001).

Conclusion: Age ≥ 50 years-old, diabetes, and inflammatory cytokines profiles at the start of PD therapy could predict for 7-year mortality in PD population.

Inflammation and elevated levels of fibroblast growth factor 23 are independent risk factors for death in chronic kidney disease

Inflammation is a consequence of chronic kidney disease (CKD) and is associated with adverse outcomes in many clinical settings. Inflammation stimulates production of fibroblast growth factor 23 (FGF23), high levels of which are independently associated with mortality in CKD. Few large-scale prospective studies have examined inflammation and mortality in patients with CKD, and none tested the interrelationships among inflammation, FGF23, and risk of death. Therefore, we conducted a prospective investigation of 3875 participants in the Chronic Renal Insufficiency Cohort (CRIC) study with CKD stages 2 to 4 to test the associations of baseline plasma interleukin-6, high-sensitivity C-reactive protein, and FGF23 levels with all-cause mortality, censoring at the onset of end-stage renal disease. During a median follow-up of 6.9 years, 550 participants died (20.5/1000 person-years) prior to end-stage renal disease. In separate multivariable-adjusted analyses, higher levels of interleukin-6 (hazard ratio per one standard deviation increase of natural log-transformed levels) 1.35 (95% confidence interval, 1.25-1.46), C-reactive protein 1.28 (1.16-1.40), and FGF23 1.45 (1.32-1.60) were each independently associated with increased risk of death. With further adjustment for FGF23, the risks of death associated with interleukin-6 and C-reactive protein were minimally attenuated. Compared to participants in the lowest quartiles of inflammation and FGF23, the multivariable-adjusted hazard ratio of death among those in the highest quartiles of both biomarkers was 4.38 (2.65-7.23) for interleukin-6 and FGF23, and 5.54 (3.04-10.09) for C-reactive protein and FGF23. Thus, elevated levels of interleukin-6, C-reactive protein, and FGF23 are independent risk factors for mortality in CKD.

Relative risk for cardiovascular morbidity in hemodialysis patients regarding gene polymorphism for IL-10, IL-6, and TNF

Uremia-related inflammation is prone to be a key factor to explain high cardiovascular morbidity in hemodialysis patients. Genetic susceptibility may be of importance, including IL-10, IL-6, and TNF. The aim was to analyze IL-10, IL-6, and TNF gene polymorphisms in a group of hemodialysis patients and to correlate the findings with cardiovascular morbidity. This study included 169 patients on regular hemodialysis at Zvezdara University Medical Center. Gene polymorphisms for IL-10, IL-6 and TNF were determined using PCR. These findings were correlated with the cardiovascular morbidity data from patient histories. Heterozygots for IL-10 gene showed significantly lower incidence of cardiovascular events (p = 0.05) and twice lower risk for development of myocardial infarction, but experienced twice higher risk for left ventricular hypertrophy. Regarding TNF gene polymorphism, patients with A allele had 1.5-fold higher risk for cerebrovascular accident and cardiovascular events and 2-fold higher risk for hypertension and peripheral vascular disease. Patients with G allele of IL-6 gene experienced 1.5-fold higher risks for cerebrovascular accident. We need studies with larger number of patients for definitive conclusion about the influence of gene polymorphisms on cardiovascular morbidity in hemodialysis patients and its importance in everyday clinical practice.

Combination with Red ginseng and Polygoni Multiflori ameliorates highfructose diet induced metabolic syndrome

BACKGROUND

Metabolic syndrome such as dyslipidemia, hypertension, obesity, impaired glucose tolerance and fatty liver, can be caused by modification of diet by means of overconsumption of high fructose diet. This study was designed to investigate whether combination with Red ginseng and Polygoni Multiflori Radix (RGPM), widely used traditional herbal medicine, ameliorates on highfructose (HF) diet-induced metabolic syndrome.

METHODS

SD rats were fed the 60% HF diet with/without rosiglitazone, and RGPM 100, 300 mg/kg/day, respectively. All groups received regular diet or HF diet, respectively, for 8 weeks. The last three groups treatment of rosiglitazone and RPGM orally for a period of 6 weeks.

RESULTS

Chronic treatment with RGPM significantly decreased body weight, fat weight and adipocyte size. RGPM significantly prevented the development of the metabolic disturbances such as hypertension, hyperlipidemia and impaired glucose tolerance. RGPM also led to increase in high density lipoprotein level in the HF group. RGPM suppressed high-fructose diet induced vascular inflammation marker expression such as adhesion molecules and ET-1 in aorta as well as increasing of C-reactive protein (CRP) levels in plasma. Similarly, RGPM attenuated hepatic lipid accumulation by inhibition of monocyte chemoattractant protein-1 (MCP-1) expression.

CONCLUSION

An administration of RGPM may be a beneficial therapy for the treatment of metabolic syndrome through the improvement of hypertension, obesity, hyperlipidemia, vascular inflammation and insulin resistance.

Elevation of Interleukin-18 Correlates With Cardiovascular, Cerebrovascular, and Peripheral Vascular Events: A Cohort Study of Hemodialysis Patients

Cardiocerebral vascular events are the major cause of mortality among patients with end-stage renal disease (ESRD). Subclinical inflammation and atherosclerosis have been implicated in the pathophysiology of ESRD. Evidence has shown the crucial role of interleukin-18 (IL-18) in inflammation. Interleukin-18 has been markedly upregulated in ESRD patients. Nevertheless, the ability of the IL-18 level to predict cardiocerebral vascular events and the correlation between IL-18 levels and cardiocerebral vascular events have not been established in hemodialysis patients.To determine whether the serum IL-18 level predicts cardiocerebral vascular events, the authors studied 171 ESRD patients. Samples were collected and patients were followed for 24 months. Demographic data, the duration of hemodialysis, nutrition status, inflammatory parameters, dialysis adequacy, and lipid profiles were analyzed to predict the outcome by using multivariate logistic regression. Cutoff points were calculated by acquiring the highest Youden index. The Kaplan-Meier method was used to scrutinize the cumulative proportion of events.The multivariate logistic regression model revealed that serum creatinine, C-reactive protein, and IL-18 levels were independent predictors for cardiocerebral vascular events. The odds ratio of events for each increase in IL-18 (pg/mL) was 1.008 for cardiocerebral vascular events. The area under the receiver operating characteristic curve of IL-18 was 0.779 ± 0.039, the overall correctness was 73%, and the Youden index was highest at a cutoff of 463 pg/mL. In the Kaplan-Meier model, patients with an IL-18 level higher than 463 pg/mL exhibited the highest probability of experiencing an adverse event during the entire follow-up period.Increased serum IL-18 could be considered as a predictor of cardiocerebral vascular events in dialysis patients. It is noteworthy that various comorbidities might interfere the expression of IL-18; therefore, further validation study is required to incorporate IL-18 in clinical use.

Pro-inflammatory cytokines and leukocyte oxidative burst in chronic kidney disease: culprits or innocent bystanders?

BACKGROUND

Pro-inflammatory cytokines are elevated in chronic kidney disease (CKD), a condition characterized by microinflammation with oxidative stress as key feature. However, their role in the inflammatory response at uraemic concentrations has not yet been defined. In this study, the contribution of cytokines on induction of leukocyte oxidative stress was investigated.

METHODS

Whole blood from healthy donors was incubated with 20-1400 pg/mL TNFα, 5-102.8 pg/mL IL-6, 20-400 pg/mL IL-1β and 75-1200 pg/mL IL-18 separately or in combination. Oxidative burst was measured, at baseline and after stimulation with fMLP (Phagoburst™). The effect of the TNFα blocker, adalimumab (Ada), was evaluated on TNFα-induced ROS production. Finally, the association between TNFα and the composite end point all-cause mortality or first cardiovascular event was analysed in a CKD population stage 4-5 (n = 121).

RESULTS

While interleukin (IL)-6, IL-1β and IL-18 alone induced no ROS activation of normal leukocytes, irrespective of concentrations, TNFα induced ROS activation at baseline (P < 0.01) and after fMLP stimulation (P < 0.05), but only at uraemic concentrations in the high range (400 and 1400 pg/mL). A similar pattern was observed with all cytokines in combination, but already at intermediate uraemic concentrations (all P < 0.05, except for monocytes after fMLP stimulation: n.s.), suggesting synergism between cytokines. ROS production induced by TNFα (400 pg/mL) and the cytokine combination was blocked with Ada. Uraemia-related oxidative stress in leukocytes of haemodialysis patients was however not blocked by Ada. In patients, TNFα was not associated to adverse events (HR: 1.52, 95% CI 0.81-2.85, P = 0.13).

CONCLUSION

Among several pro-inflammatory cytokines, TNFα alone was pro-oxidative but only at high-range uraemic concentrations. Adding a TNFα blocker, Ada, blocked this ROS production, but not the oxidative stress in blood samples from haemodialysis patients, suggesting that other uraemic toxins than TNFα are more crucial in this process. However, the lack of association between TNFα and mortality suggests that the role of TNFα-linked oxidative stress is limited.

Increased dialysate MCP-1 is associated with cardiovascular mortality in peritoneal dialysis patients: a prospective observational study

BACKGROUND

The aim of this study was to investigate the association between the dialysate MCP-1 (dMCP-1) and systemic inflammatory and nutritional markers in peritoneal dialysis (PD) patients. In addition, we examined the prognostic value of dMCP-1 on all-cause or cardiovascular mortality in these patients.

METHODS

We prospectively followed 169 prevalent PD patients from April 1st 2008 to December 31st 2012. At baseline, dMCP-1 and serum biochemical parameters including high sensitivity CRP (hs-CRP) and albumin were checked. All-cause mortality and cause of death were evaluated during the follow-up period. Based on the median level of dMCP-1, patients were classified as either low or high dMCP-1 groups.

RESULTS

Mean age, hs-CRP, and D/Pcr ratio at 4 h were significantly higher, while serum albumin levels and %lean body mass (LBM) were significantly lower in the high dMCP-1 group. During the mean follow-up period of 47.7 months, all-cause mortality and cardiovascular mortality rate were significantly higher in the high dMCP-1 group (9.6 and 6.3 per 100 person-years, respectively) compared to the low dMCP-1 group (5.1 and 3.1 per 100 person-years, respectively; p = 0.021, 0.038). In multivariate Cox analysis, high dMCP-1 was a significant independent predictor of all-cause mortality (hazard ratio: 1.83, 95% confidence interval: 1.03-3.24, p = 0.039).

CONCLUSIONS

dMCP-1 levels are closely correlated with nutritional and systemic inflammatory markers in PD patients. In addition, increased dMCP-1 is significantly associated with higher all-cause and cardiovascular mortality. These findings suggest that local peritoneal inflammation could contribute to poor clinical outcomes in PD patients.

The peptidic middle molecules: is molecular weight doing the trick?

Chronic kidney disease (CKD) is characterized by a gradual endogenous intoxication caused by the progressive accumulation of bioactive compounds that in normal conditions would be excreted and/or metabolized by the kidney. Uremic toxicity now is understood as one of the potential causes for the excess of cardiovascular disease and mortality observed in CKD. An important family of uremic toxins is that of the peptidic middle molecules, with a molecular weight ranging between 500 and 60,000 Da, which makes them, as a consequence, difficult to remove in the process of dialysis unless the dialyzer pore size is large enough. This review provides an overview of the main and best-characterized peptidic middle molecules and their role as potential culprits of the cardiometabolic complications inherent to CKD patients.

Anti-Inflammatory and Anti-Oxidative Nutrition in Hypoalbuminemic Dialysis Patients (AIONID) study: results of the pilot-feasibility, double-blind, randomized, placebo-controlled trial

BACKGROUND

Low serum albumin is common and associated with protein-energy wasting, inflammation, and poor outcomes in maintenance hemodialysis (MHD) patients. We hypothesized that in-center (in dialysis clinic) provision of high-protein oral nutrition supplements (ONS) tailored for MHD patients combined with anti-oxidants and anti-inflammatory ingredients with or without an anti-inflammatory appetite stimulator (pentoxifylline, PTX) is well tolerated and can improve serum albumin concentration.

METHODS

Between January 2008 and June 2010, 84 adult hypoalbuminemic (albumin <4.0 g/dL) MHD outpatients were double-blindly randomized to receive 16 weeks of interventions including ONS, PTX, ONS with PTX, or placebos. Nutritional and inflammatory markers were compared between the four groups.

RESULTS

Out of 84 subjects (mean ± SD; age, 59 ± 12 years; vintage, 34 ± 34 months), 32 % were Blacks, 54 % females, and 68 % diabetics. ONS, PTX, ONS plus PTX, and placebo were associated with an average change in serum albumin of +0.21 (P = 0.004), +0.14 (P = 0.008), +0.18 (P = 0.001), and +0.03 g/dL (P = 0.59), respectively. No related serious adverse events were observed. In a predetermined intention-to-treat regression analysis modeling post-trial serum albumin as a function of pre-trial albumin and the three different interventions (ref = placebo), only ONS without PTX was associated with a significant albumin rise (+0.17 ± 0.07 g/dL, P = 0.018).

CONCLUSIONS

In this pilot-feasibility, 2 × 2 factorial, placebo-controlled trial, daily intake of a CKD-specific high-protein ONS with anti-inflammatory and anti-oxidative ingredients for up to 16 weeks was well tolerated and associated with slight but significant increase in serum albumin levels. Larger long-term controlled trials to examine hard outcomes are indicated.

Subclinical Atherosclerosis, Endothelial Function, and Serum Inflammatory Markers in Chronic Kidney Disease Stages 3 to 4

Different inflammatory markers, brachial artery flow-mediated dilatation (FMD), and brachial intima-media thickness (bIMT) were measured in 50 patients with chronic kidney disease (CKD) stages 3 to 4 with estimated glomerular filtration rate (eGFR) and 35 age- and gender-matched controls. The bIMT was significantly increased in the patients with CKD compared with controls (0.43 mm [0.42, 0.45] vs 0.34 mm [0.32, 0.36]; P < .001). There was no significant difference in FMD between the study groups (4.7% vs 5.3%; P = .56). There were significant correlations between bIMT and high-sensitive C-reactive protein, vascular cellular adhesion molecule 1, tumor necrosis factor, and interleukin 6 ( P < .05). However, eGFR adjusted for age and gender was the best predictor of bIMT. In conclusion, bIMT and inflammatory markers were increased in patients with CKD compared with the controls. Furthermore, significant correlations between bIMT and inflammatory activity in patients with CKD were observed. The eGFR adjusted for age and gender was the best predictor of bIMT.

Accumulation of retained nonfunctional arteriovenous grafts correlates with severity of inflammation in asymptomatic ESRD patients

BACKGROUND

The contribution of multiple retained nonfunctional arteriovenous grafts (AVGs) to the burden of chronic inflammation in chronic hemodialysis patients has not been well studied. Here, we sought to evaluate the association between plasma levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha) and albumin and the number of retained nonfunctional AVGs.

METHODS

This cross-sectional study enrolled 91 prevalent patients undergoing in-center hemodialysis without evidence of infection or inflammation. A baseline blood sample was obtained at study enrollment. A general linear model (GLM) was used to compare levels of biomarkers of systemic inflammation across groups defined by the number of retained, nonfunctional AVGs.

RESULTS

A total of 43 patients had one or more retained thrombosed AVG and had significantly greater plasma log-CRP levels compared with patients without a previous AVG (P= 0.036), regardless of the current AV access type. Using a GLM, we found that for every additional retained thrombosed AVG, plasma log-CRP, log-IL-6 and TNF-alpha concentrations increased significantly by 0.30 mg/L (P= 0.011), 0.18 pg/mL (P= 0.046) and 0.72 pg/mL (P= 0.046), respectively, following adjustment.

CONCLUSIONS

Hence, the severity of inflammation increases with the number of retained nonfunctional AVG's, suggesting that AVG accumulation may contribute to the cardiovascular morbidity and mortality associated with chronic inflammation in asymptomatic end-stage renal disease (ESRD) patients. Further study is indicated to determine whether patients with one or more thrombosed, retained AVG may benefit from periodic screening with CRP monitoring to identify those patients who may benefit from AVG resection.

Biomarkers in hemodialysis patients

Patients with chronic kidney disease (CKD) are, compared to the general population, at higher risk of cardiovascular disease (CVD), including sudden death, coronary artery disease (CAD), congestive heart failure (HF), stroke, and peripheral artery disease. The presence of CVD is independently associated with kidney function decline. Renal insufficiency is a strong and independent predictor of mortality in patients with different CKD stages. The interplay of traditional and nontraditional risk factors is complex such that risk factor profiles are different in CKD patients. Seemingly, paradoxical associations between traditional risk factors and cardiovascular outcome complicate efforts to identify real cardiovascular etiology in these patients. Additional tools are often required to aid clinical assessment of cardiovascular risk. Recently, a number of cardiovascular biomarkers were identified as predictors of outcome in CVD. These may be used to guide early diagnosis and therapy for CVD or may predict outcome in CKD. This review focuses on the potential diagnostic and prognostic use of some important new biomarkers including brain natriuretic peptide (BNP), cardiac troponins (cTns), inflammatory markers, adhesion molecules, and asymmetric dimethylarginine (ADMA) in CKD as well as those patients with end-stage renal failure.

Correlates of resistin in children with chronic kidney disease: the chronic kidney disease in children cohort

OBJECTIVE

To test the hypothesis that resistin is associated with insulin resistance and inflammation in pediatric patients with chronic kidney disease (CKD).

STUDY DESIGN

This study is a cross-sectional analysis of 319 children in the Chronic Kidney Disease in Children cohort, a large cohort of children with stage II-IV CKD. Univariate and multivariate regression modeling was used to evaluate the association of serum resistin level with glomerular filtration rate (GFR), demographic data, and cardiovascular risk factors, including inflammatory cytokines, insulin resistance, and serum lipids.

RESULTS

In univariate analyses, serum resistin level was negatively correlated with GFR (P < .01). Increased serum resistin was associated with elevated inflammatory cytokines, including interleukin (IL)-6 (P < .01), IL-10 (P < .01), and tumor necrosis factor-α (P < .01). Resistin level was not associated with insulin resistance, although it was positively correlated with serum triglycerides (P < .01) and negatively correlated with high-density lipoprotein cholesterol (P < .01). In multivariate analysis, GFR (β = -0.01; P < .001), IL-6 (β = 0.18; P < .001), IL-10 (β = 0.09; P = .01), and pubertal status (β = 0.18; P < .01) were significantly associated with serum resistin level.

CONCLUSION

These results indicate that serum resistin level increases with GFR decline and is involved in the inflammatory milieu present in CKD.

Chronic Inflammation and Coronary Atherosclerosis in Patients with End-Stage Renal Disease

The key role of chronic inflammation in the pathogenesis of atherosclerosis has become increasingly apparent in recent years based on the results of experimental, epidemiologic and clinical studies. Coronary artery disease and its complications occur with disproportionately high frequency in patients with end-stage renal disease (ESRD) and contribute substantially to cardiovascular morbidity and mortality in this population. Traditional cardiovascular risk factors occur commonly in patients with ESRD. In addition, a variety of patient-related and dialysis-related factors unique to ESRD predispose to chronic inflammation and by doing so are thought to contribute to coronary atherosclerosis and its complications. These risk factors may serve as therapeutic targets and as such may offer the potential for altering the natural history of coronary atherosclerosis in ESRD.

Oxidized high-density lipoprotein as a risk factor for cardiovascular events in prevalent hemodialysis patients

BACKGROUND AND OBJECTIVES

Here, we assessed the impact of oxidized high-density lipoprotein (oxHDL), dysfunctional HDL, on mortality and cardiovascular disease (CVD) events in prevalent HD patients and compared oxHDL to interleukin-6 (IL-6), a strong predictor of CVD events in HD patients.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

This prospective study examined a cohort of prevalent HD patients (n=412). Blood samples were obtained at baseline to measure lipids, high-sensitive C-reactive protein (hsCRP), IL-6, oxidized low-density lipoprotein, N-terminal pro B-type natriuretic peptide, intercellular adhesion molecule 1 (ICAM-1), myeloperoxidase, adiponectin, and oxHDL. Carotid intima-media thickness (CIMT) was assessed at baseline and 3-year follow-up. Nutritional status was assessed by subjective global assessment (SGA), body mass index, and geriatric nutritional risk index (GNRI). After the baseline assessment, study patients were prospectively followed up (mean observational period, 40 months).

RESULTS

At baseline, patients with high oxHDL had a worse nutritional state and higher HDL-cholesterol (HDL-chol), ICAM-1, and adiponectin levels and a higher oxHDL/HDL-chol ratio than low oxHDL patients. A combination of high oxHDL and high IL-6 was significantly associated with increased CIMT at baseline and a larger increase in CIMT at 3-year follow-up. High oxHDL did not predict all-cause mortality; however, it was significantly associated with CVD-related mortality and composite CVD events, particularly with concomitant high IL-6. These associations were confirmed in multivariate Cox hazard models adjusted with confounding variables.

CONCLUSIONS

High oxHDL, particularly with concomitant high IL-6, may be associated with an increased risk of CVD events and CVD-related mortality in prevalent HD patients.

IL-6 levels, nutritional status, and mortality in prevalent hemodialysis patients

BACKGROUND AND OBJECTIVES

The influence of serum IL-6 levels on nutritional status in chronic hemodialysis (HD) patients remains to be elucidated. The present report describes a prospective longitudinal study of IL-6 levels and nutritional parameters to determine whether high IL-6 levels are independently associated with nutritional status over time in a cohort of prevalent hemodialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

85 clinically stable hemodialysis patients (37.6% women), with a mean age of 66.5 ± 10.6 years, were studied after exclusion of patients with BMI < 20 kg/m(2) and/or serum albumin <35 g/L. IL-6, dietary energy and protein intake, and biochemical markers of nutrition and body composition (anthropometry and bioimpedance analysis) were measured at baseline and at 6, 12, 18, and 24 months following enrollment. Observation of this cohort was continued over 2 additional years.

RESULTS

IL-6 levels increased with time in both unadjusted (linear estimate: 2.57 ± 0.44 pg/ml per 2 yrs; P = 0.001) and adjusted models (linear estimate: 2.35 ± 0.57 pg/ml per 2 yrs; P = 0.049). Significant reductions of daily energy intake, laboratory markers (albumin, transferrin, cholesterol, creatinine), and body composition (fat mass) with higher IL-6 levels were observed over the duration of the longitudinal observation period. However, none of the studied parameters were associated with changes in IL-6 levels over time (IL-6-by-time interactions were NS). Furthermore, cumulative incidences of survival were correlated with the baseline serum IL-6 levels (P = 0.004 by log-rank test). Finally, for each pg/ml increase in IL-6 level, the hazard ratio for death from all causes was 1.06 (95% CI 1.01 to 1.10) after adjustment for demographic and clinical parameters.

CONCLUSIONS

Our results suggest that higher serum IL-6 levels are associated with all-cause mortality without additional changes in clinical and laboratory markers of nutritional status in clinically stable HD patients.

Role of Growth Hormone Deficiency and Treatment in Chronic Kidney Disease

Malnutrition and inflammation are strong predictors of mortality in advanced kidney disease, especially in patients on renal replacement therapy. The complex relationship between kidney disease, uremia, and malnutrition significantly contributes to the increased morbidity and mortality in this patient population potentially through a relative deficiency in growth hormone (GH). With an approximate 26 million Americans currently affected by some stage of chronic kidney disease and a predicted 750,000 people to be on dialysis by 2020, there is a need to develop innovative strategies aimed at reducing the high mortality seen in dialysis patients. We will review evidence on one such intervention with infusion of recombinant GH to improve the nutritional and inflammatory state, thereby expecting to improve the mortality and morbidity in this patient population.

STAT1 as a novel therapeutical target in pro-atherogenic signal integration of IFNγ, TLR4 and IL-6 in vascular disease

Inflammation participates importantly in host defenses against infectious agents and injury, but it also contributes to the pathophysiology of atherosclerosis. Recruitment of blood leukocytes to the injured vascular endothelium characterizes the initiation and progression of atherosclerosis and involves many inflammatory mediators, modulated by cells of both innate and adaptive immunity. The pro-inflammatory cytokine, interferon (IFN)-γ derived from T cells, is vital for both innate and adaptive immunity and is also expressed at high levels in atherosclerotic lesions. As such IFN-γ plays a crucial role in the pathology of atherosclerosis through activation of signal transducer and activator of transcription (STAT) 1. Toll-like receptors (TLRs) are innate immune pattern recognition receptors (PRRs) expressed on a variety of cells, and thus initiate and sustain the inflammatory response in atherosclerosis. More recent studies have revealed that STAT1 is involved in the signaling events mediated by TLR4, leading to increased expression of several pro-inflammatory and pro-atherogenic mediators. By upregulating members of the Suppressors Of Cytokine Signaling (SOCS) family that regulate cellular responsiveness to immune signals, IFNγ and TLR4-activated pathways have also shown to inhibit IL-6 STAT3-dependent anti-inflammatory signaling and potentially shift IL-6 to a STAT1 activating pro-inflammatory cytokine. Consequently, STAT1 has been identified as a point of convergence for the cross-talk between the pro-atherogenic IFN-γ, TLR4 and IL-6 activated pathways in immune as well as vascular cells, as such amplifying pro-inflammatory signals. This results in augmented smooth muscle cell (SMC) and leukocyte migration, leukocyte to endothelial cell (EC) adhesion and foam cell formation, and could encompass a novel mechanism involved in the initiation and progression of atherosclerosis. Therefore, application of small inhibitory compounds that specifically interact with the SH2-phosphotyrosine pocket of STAT1, proposed here as a novel working mechanism for the known STAT1 inhibitor fludarabine, could be a promising tool in the development of a therapeutical strategy for atherosclerosis.

Quality-of-life and mortality in hemodialysis patients: roles of race and nutritional status

BACKGROUND AND OBJECTIVES

Maintenance hemodialysis (MHD) patients often have protein-energy wasting, poor health-related quality of life (QoL), and high premature death rates, whereas African-American MHD patients have greater survival than non-African-American patients. We hypothesized that poor QoL scores and their nutritional correlates have a bearing on racial survival disparities of MHD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined associations between baseline self-administered SF36 questionnaire-derived QoL scores with nutritional markers by multivariate linear regression and with survival by Cox models and cubic splines in the 6-year cohort of 705 MHD patients, including 223 African Americans.

RESULTS

Worse SF36 mental and physical health scores were associated with lower serum albumin and creatinine levels but higher total body fat percentage. Spline analyses confirmed mortality predictability of worse QoL, with an almost strictly linear association for mental health score in African Americans, although the race-QoL interaction was not statistically significant. In fully adjusted analyses, the mental health score showed a more robust and linear association with mortality than the physical health score in all MHD patients and both races: death hazard ratios for (95% confidence interval) each 10 unit lower mental health score were 1.12 (1.05-1.19) and 1.10 (1.03-1.18) for all and African American patients, respectively.

CONCLUSIONS

MHD patients with higher percentage body fat or lower serum albumin or creatinine concentration perceive a poorer QoL. Poor mental health in all and poor physical health in non-African American patients correlate with mortality. Improving QoL by interventions that can improve the nutritional status without increasing body fat warrants clinical trials.

Impact of seropositivity to Chlamydia pneumoniae and anti-hHSP60 on cardiovascular events in hemodialysis patients

Autoimmunity to heat shock protein 60 (HSP60) has been related to atherosclerosis. Chlamydia pneumoniae (CP), the most studied infectious agent implicated in promoting atherosclerosis, produces a form of HSP60, which can induce an autoimmune response, due to high antigenic homology with human HSP60 (hHSP60). In this study, we evaluated the correlations among anti-hHSP60 antibodies, CP infection, and cardiovascular disease (CVD) in a high-risk population, such as patients undergoing hemodialysis (HD). Thirty-two patients (67.9 ± 13.9 years; male/female, 23:9) on regular HD were enrolled. Global absolute cardiovascular risk (GCR) was assessed using the Italian CUORE Project's risk charts, which evaluate age, gender, smoking habits, diabetes, systolic blood pressure, and serum cholesterol. The occurrence of cardiovascular events during a 24-month follow-up was recorded. Seropositivity to CP and the presence of anti-hHSP60 antibodies were tested by specific enzyme-linked immunosorbent assays. Inflammation was assessed by measurement of C-reactive protein (CRP) serum levels. Fifteen healthy sex and age-matched (61.9 ± 9.5 years; male/female, 11:4) subjects were the control group. Fifteen of 32 patients resulted seropositive for CP. CP + patients were older than CP-, while they did not differ for GCR, CRP, and dialytic parameters. CVD incidence was significantly higher in CP+ (9 CP+ vs 2 CP-, p < 0.05). Cox analysis recognized that the incidence of CVD was independently correlated with seropositivity to CP (HR, 7.59; p = 0.01; 95% CI = 1.63-35.4). On the other hand, there were no significant differences in anti-hHSP60 levels among CP+, CP- and healthy subjects: 18.11 μg/mL (14.8-47.8), 31.4 μg/mL (23.2-75.3), and 24.72 μg/mL (17.7-41.1), respectively. Anti-hHSP60 did not correlate to GCR, CRP, and incidence of CVD. In conclusion, our data suggest that anti-hHSP60 autoimmune response is not related to CP infection and CP-related CVD risk in HD patients.

IFNγ-dependent SOCS3 expression inhibits IL-6-induced STAT3 phosphorylation and differentially affects IL-6 mediated transcriptional responses in endothelial cells

IL-6 has pro- and anti-inflammatory effects and is involved in endothelial cell (EC) dysfunction. The anti-inflammatory effects of IL-6 are mediated by signal transducer and activator of transcription-3 (STAT3), which is importantly controlled by suppressor of cytokine signaling 3 (SOCS3). Therefore, cytokines that modulate SOCS3 expression might inhibit the anti-inflammatory effects of IL-6. We hypothesized that in EC, interferon-γ (IFNγ)-induced SOCS3 expression leads to inhibition of IL-6-induced STAT3 activation and IL-6-dependent expression of anti-, but not pro-inflammatory, target genes. IFNγ activated STAT1 and STAT3 and increased SOCS3 expression in EC. IL-6 only activated STAT3 and induced SOCS3 expression. IFNγ pretreatment of EC inhibited IL-6-induced STAT3 activation accompanied by increased SOCS3 protein. Inhibition of SOCS3 expression, using costimulation, Act-D, and small interfering RNA (siRNA), subsequently implicated the importance of IFNγ-induced SOCS3 in this phenomenon. Pretreatment of EC with IFNγ also affected the transcriptional program induced by IL-6. We identified 1) IL-6 anti-inflammatory target genes that were inhibited by IFNγ, 2) IFNγ-target genes of pro-inflammatory nature that were increased in response to IL-6 in the presence of IFNγ, and 3) a set of target genes that were increased upon IL-6 or IFNγ alone, or combined IFNγ and IL-6. In summary, by increasing SOCS3 expression in EC, IFNγ can selectively inhibit STAT3-dependent IL-6 signaling. This in turn leads to decreased expression of some EC protective genes. In contrast, other genes of pro-inflammatory nature are not inhibited or even increased. This IFNγ-induced shift in IL-6 signaling to a pro-inflammatory phenotype could represent a novel mechanism involved in EC dysfunction.

Association of relatively low serum parathyroid hormone with malnutrition-inflammation complex and survival in maintenance hemodialysis patients

BACKGROUND

Low serum parathyroid hormone (PTH) has been implicated as a primary biochemical marker of adynamic bone disease in individuals with chronic kidney disease (CKD) who undergo maintenance hemodialysis (MHD) treatment. We hypothesized that the malnutrition-inflammation complex is associated with low PTH levels in these patients and confounds the PTH-survival association.

METHODS

We examined 748 stable MHD outpatients in southern California and followed them for up to 5 years (October 2001-December 2006).

RESULTS

In 748 MHD patients, serum PTH <150pg/mL was more prevalent among non-blacks and diabetics. There was no association between serum PTH and coronary artery calcification score, bone mineral density, or dietary protein or calorie intake. Low serum PTH was associated with markers of protein-energy wasting and inflammation, and this association confounded the relationship between serum PTH and alkaline phosphatase. Although 5-year crude mortality rates were similar across PTH increments, after adjustment for the case-mix and surrogates of malnutrition and inflammation, a moderately low serum PTH in 100-150pg/mL range was associated with the greatest survival compared to other serum PTH levels, i.e., a death hazard ratio of 0.52 (95% confidence interval: 0.29-0.92, p<0.001) compared to PTH of 300-600pg/mL (reference).

CONCLUSIONS

Low serum PTH may be another facet of the malnutrition-inflammation complex in CKD, and after controlling for this confounder, a moderately low PTH in 100-150pg/mL range appears associated with the greatest survival. Limitations of observational studies should be considered.

Dietary-induced hyperparathyroidism affects serum and gingival proinflammatory cytokine levels in rats

BACKGROUND

Poor diet and inadequate nutrition are suggested to affect the periodontium as well as impair the systemic health. This study investigated the systemic and periodontal effects of dietary-induced hyperparathyroidism (dHPT) by evaluating serum and gingival proinflammatory cytokine levels.

METHODS

Twenty-four Sprague-Dawley rats were used in the study. dHPT was induced in 12 rats by calcium/phosphorus imbalance, and 12 rats were fed a standard diet (SD). Afterward, endotoxin-induced periodontitis was induced on the right mandibular molar teeth (mmt). Four study groups were created: dHPT + mmt without periodontitis (group 1), dHPT + mmt with periodontitis (group 2), SD + mmt with periodontitis (group 3), and SD + mmt without periodontitis (group 4). Interleukin (IL)-1beta and tumor necrosis factor-alpha (TNF-alpha) levels were measured by enzyme-linked immunosorbent assay to evaluate the proinflammatory cytokine profiles. Serum cytokines were analyzed in the blood samples collected prior to periodontitis induction, whereas gingival cytokines were analyzed in the gingival supernatants of the four groups.

RESULTS

Serum cytokines were higher in dHPT rats than in SD rats (P <0.001), with a positive correlation between parathormone and the cytokines (P <0.001). Gingival cytokines were highest in group 2 and lowest in group 4 (group 2 > group 3 > group 1) (P <0.001). There was a positive correlation between parathormone and the gingival cytokines in group 1 (P <0.001 for IL-1beta; P <0.01 for TNF-alpha).

CONCLUSION

The results suggested that increased serum proinflammatory cytokine production may be a complication of dHPT, and this may affect healthy and diseased periodontia by increasing gingival proinflammatory cytokine levels.

Persistent inflammation as a catalyst for other risk factors in chronic kidney disease: a hypothesis proposal

Because inflammation by now is a "traditional" finding that predicts poor outcome and cardiovascular events in the vast majority of patients with ESRD, it could be argued that inflammatory biomarkers should not longer be considered "novel" risk factors. In this review, we forward the hypothesis that, in addition to putative direct proatherogenic effects, persistent inflammation may serve as a catalyst and, in the toxic uremic milieu, modulate the effects of other concurrent vascular and nutritional risk factors. We discuss some recent observational studies, suggesting that the presence of persistent inflammation magnifies the risk for poor outcome via mechanisms related to self-enhancement of the inflammatory cascade and exacerbation of both the wasting and the vascular calcification processes. Because persistent inflammation may be the silent culprit of other commonly observed pathophysiologic alterations in chronic kidney disease, it is imperative that inflammatory markers be regularly monitored and therapeutic attempts be made to target persistent low-grade inflammation in this patient group.

Cytokines, atherogenesis, and hypercatabolism in chronic kidney disease: a dreadful triad

The term cytokine clusters denotes a copious family of molecules and correspondent receptors implicated in numerous processes mediating health and disease. In the context of chronic kidney disease (CKD), generation and metabolism of most of these cytokines are disturbed. Available evidence suggests that cytokine imbalances contribute to the progression of common CKD complications, such as atherosclerosis, mineral-bone disease, and protein-energy wasting via pleiotropic effects. The belief that cytokine CKD research is solely represented by interleukins (IL) and tumor-necrosis factors (TNF) (mainly IL-6 and TNF-alpha) is a common misconception among nephrologists. We here explore recent findings concerning the pathophysiological role of various cytokines in uremic complications, and discuss how cytokines could be used as novel potential therapeutic targets in CKD. At the same time, we provide a brief overview of current discoveries in the main transforming growth factors and chemokines.

Inflammation as a cause of malnutrition, atherosclerotic cardiovascular disease, and poor outcome in hemodialysis patients

Cardiovascular disease (CVD) remains the major cause of morbidity and mortality in end-stage renal disease (ESRD) patients treated by hemodialysis (HD). Although traditional risk factors are common in dialysis patients, they may not alone be sufficient to account for the unacceptable high prevalence of CVD in this patient group. Recent evidence demonstrates that chronic inflammation, a nontraditional risk factor that is commonly observed in HD patients, may cause malnutrition and progressive atherosclerotic CVD by several pathogenetic mechanisms. The cause(s) of inflammation in HD patients is multifactorial and includes both dialysis-related (such as graft and fistula infections, bioincompatibility, impure dialysate, and back-filtration) and dialysis-unrelated factors. Although inflammation may reflect underlying CVD, an acute-phase reaction may also be a direct cause of vascular injury. Available data suggest that proinflammatory cytokines play a central role in the genesis of both malnutrition and CVD in ESRD. Thus, it could be speculated that suppression of the vicious cycle of malnutrition, inflammation, and atherosclerosis (MIA syndrome) would improve survival in dialysis patients. As there is not yet any recognized, or even proposed, targeted treatment for ESRD patients with chronic inflammation; it would be of considerable interest to study the long-term effect of various anti-inflammatory treatment strategies on nutritional and cardiovascular status as well as outcome in these patients.

Infectious Risk Factors for Atherosclerotic Vascular Disease in Hemodialysis Patients—Chlamydia pneumoniaebut notHelicobacter pylorior Cytomegalovirus is Associated with Increased C‐Reactive Protein

BACKGROUND

Cardiovascular disease is a major problem in patients with chronic renal failure leading to increased mortality. Several infectious agents have been implicated to be associated with atherosclerosis. We were interested to evaluate whether there is a correlation between a past infection with Chlamydia pneumoniae (Cpn), Helicobacter pylori (Hp) or cytomegalovirus (CMV) and the manifestation of a symptomatic atherosclerotic disease in patients with endstage renal failure.

METHODS AND RESULTS

Patients (n=267) on hemodialysis were investigated. In 101 patients with an apparent atherosclerotic disease (case group) increased IgA levels against Cpn were found (p < or = 0.0001 vs. controls; n=33). Nearly 45% of the case group had a history of myocardial infarction (MI) (p < or = 0.0001). Prior stroke was found in about 30% of patients in the case group (p < or = 0.002). Elevated CRP levels were identified as an independent risk factor for atherosclerosis in all groups. IgA seropositivity against Cpn correlated with elevated CRP values for all atherosclerotic patients (p < or = 0.001), especially in the group of patients with MI (p < or = 0.019) and peripheral vascular disease (p < or = 0.005). There was no correlation between CMV (IgG, IgM) or Hp (IgA, IgG) seropositivity and atherosclerotic disease.

CONCLUSION

IgA seropositivity for Cpn and elevated CRP values but not Hp or CMV was associated with an increased rate of symptomatic atherosclerotic manifestations as MI, stroke, cerebral or peripheral atherosclerosis in patients with endstage renal disease on hemodialysis.

Influence of single-nucleotide polymorphisms on C-reactive protein levels in chronic kidney disease before and after kidney transplantation

INTRODUCTION

We sought to evaluate 2 single-nucleotide polymorphisms (SNPs) in the C-reactive protein (CRP) gene promoter region for their effects on CRP levels in chronic kidney disease (CKD) patients before and after a successful kidney transplantation.

METHODS

Fifty CKD patients were evaluated before and at the first and second years after the graft. Two SNPs were studied, a bi-allelic (G-->A) at the -409 and a tri-allelic (C-->T-->A) variation at the -390 position in the CRP gene.

RESULTS

All patients presented the -409GG genotype. At the -390 position, the "A" allele was not found; there were 15 "CC" patients, 11 "TT" patients, and 24 "CT" patients. CRP levels were different among patients with various genotypes (P < .019). Also the presence of the allele "T" was sufficient to determine differences in CRP levels both in pretransplantation (P = .045) and at 1 year posttransplantation (P = .011), but not at the second year (P = .448).

CONCLUSION

SNPs at the -390 position of the CRP gene promoter region influence CRP basal levels in such a way that the "C" allele correlated with the lowest and the "T" with the highest. We did not observe this influence in our patients at the second year posttransplantation.

Atherosclerosis in hemodialysis patients--the role of microinflammation

INTRODUCTION

Cardiovascular diseases (CVDs) are the most frequent cause of morbidity and mortality in patients with end-stage renal disease, and the risk for coronary heart disease is higher among the hemodialysis (HD) patients than in the general population. This excess risk for coronary heart disease is not entirely explained by traditional risk factors for CVDs. The aim of the study was to determine possible correlations between asymptomatic atherosclerosis and inflammatory markers (high sensitivity CRP [hsCRP], interleukin 6 [IL-6], tumor necrosis factor-alpha [TNF-alpha], interleukin 2 receptor [IL-2R], and selective adhesion molecules ICAM-1 and VCAM-1) in HD patients.

PATIENTS AND METHODS

In our study, 95 HD patients, 56 (59%) male and 39 (41%) female, were included. The mean age was 60 +/- 13 years, ranging from 22-81 years. Using B-mode ultrasonography (US), we measured intima-media thickness (IMT) and plaque occurrence (markers of asymptomatic atherosclerosis) in carotid arteries in these patients. In the 1-4 weeks after US examination, we took blood samples from patients to determine serum concentrations of inflammatory markers.

RESULTS

The mean IMT value was 0.83 +/- 0.21 mm, ranging from 0.5 to 2 mm. The plaques were found in 63 (84%) of HD patients. Correlations between IMT values and serum concentrations of IL-2R (r = 0.269; p < 0.022) and VCAM-1 (r = 0.290; p < 0.014) were found. Multiple linear regression analysis showed relationship between IMT values and IL-2R (p = 0.049). No relationship between inflammatory markers and plaques was found.

CONCLUSION

The results indicate that atherosclerosis in HD patients correlates with some nontraditional risk factors--the markers of inflammation.