Interleukin-8 Is a Powerful Prognostic Predictor of All-Cause and Cardiovascular Mortality in Dialytic Patients

Role of Uremic Toxins in Vascular Inflammation Associated with Chronic Kidney Disease

Cardiovascular disease (CVD) is a major complication of chronic kidney disease (CKD), despite improvements in patient care. Vascular inflammation is a crucial process in the pathogenesis of CVD and a critical factor in the cardiovascular complications in CKD patients. CKD promotes a pro-inflammatory environment that impacts the vascular wall, leading to endothelial dysfunction, increased oxidative stress, and vascular remodeling. The uremic toxins that accumulate as kidney function declines are key contributors to vascular inflammatory processes. Our review will examine how CKD leads to vascular inflammation, paving the way to CVD. We will provide an overview of the mechanisms of vascular inflammation induced by uremic toxins, with a particular focus on those derived from tryptophan metabolism. These toxins, along with their receptor, the aryl hydrocarbon receptor (AHR), have emerged as key players linking inflammation and thrombosis. A deeper understanding of the mechanisms underlying inflammation in CKD, particularly those driven by uremic toxins, could reveal valuable therapeutic targets to alleviate the burden of CVD in CKD patients.

Aortic valve calcification is promoted by interleukin-8 and restricted through antagonizing CXC motif chemokine receptor 2

AIMS

Inflammatory cytokines play a critical role in the progression of calcific aortic valve disease (CAVD), for which there is currently no pharmacological treatment. The aim of this study was to test the hypothesis that interleukin-8 (IL-8), known to be involved in arterial calcification, also promotes aortic valve calcification (AVC) and to evaluate whether pharmacologically blocking the IL-8 receptor, CXC motif chemokine receptor 2 (CXCR2), could be effective in preventing AVC progression.

METHODS AND RESULTS

A cohort of 195 patients (median age 73, 74% men) diagnosed with aortic valve stenosis (severe in 16.9% of cases) were prospectively followed by CT for a median time of 2.6 years. A Cox proportional hazards regression analysis indicated that baseline IL-8 serum concentrations were associated with rapid progression of AVC, defined as an annualized change in the calcification score by CT ≥ 110 AU/year, after adjustment for age, gender, bicuspid anatomy, and baseline disease severity. In vitro, exposure of primary human aortic valvular interstitial cells (hVICs) to 15 pg/mL IL-8 induced a two-fold increase in inorganic phosphate (Pi)-induced calcification. IL-8 promoted NFκB pathway activation, MMP-12 expression, and elastin degradation in hVICs exposed to Pi. These effects were prevented by SCH527123, an antagonist of CXCR2. The expression of CXCR2 was confirmed in hVICs and samples of aortic valves isolated from patients with CAVD, in which the receptor was mainly found in calcified areas, along with MMP-12 and a degraded form of elastin. Finally, in a rat model of chronic kidney disease-associated CAVD, SCH527123 treatment (1 mg/kg/day given orally for 11 weeks) limited the decrease in aortic cusp separation, the increase in maximal velocity of the transaortic jet, and the increase in aortic mean pressure gradient measured by echocardiography, effects that were associated with a reduction in hydroxyapatite deposition and MMP-12 expression in the aortic valves.

CONCLUSION

Overall, these results highlight, for the first time, a significant role for IL-8 in the progression of CAVD by promoting calcification via a CXCR2- and MMP-12-dependent mechanism that leads to elastin degradation, and identify CXCR2 as a promising therapeutic target for the treatment of CAVD.

The effects for inflammatory responses by CPP with different colloidal properties in hemodialysis patients

Calciprotein particles (CPPs) are colloids composed of solid-phase calcium-phosphate and serum protein fetuin-A. CPPs form a polydispersed system with different particle size and density. CPPs with specific physical properties can induce calcification and innate immune responses in cultured cells. In hemodialysis patients, blood CPP levels were reported to correlate with vascular calcification and inflammation. However, little is known about relation between these disorders and physical properties of CPPs. Here, we show that the association between physical properties of plasma CPPs and serum levels of inflammatory cytokines/chemokines in 78 hemodialysis out-patients by cross-sectional study. Patients with cardiovascular disease (CVD) had significantly higher high density CPP (H-CPP) levels than patients without CVD but not low density CPP (L-CPP). Seven cytokines/chemokines (EGF, eotaxin, IL-8, IP-10, MCP-1, MIP-1, MIP-1β and TNFα) were detectable in the serum samples from > 95% of the patients. In multivariate regression analysis, H-CPP was positively associated with eotaxin after adjusting for age, gender, smoking, serum phosphate and FGF23. L-CPP was negatively associated with IL-8 after adjusting for age, gender, serum albumin, phosphate and FGF23. High H-CPP levels were associated with pro-inflammatory response, whereas L-CPPs were associated with anti-inflammatory response. CPPs with different physical properties may impact differently on pathophysiology in HD patients.

A randomized prospective cross over study on the effects of medium cut-off membranes on T cellular and serologic immune phenotypes in hemodialysis

Extended cut-off filtration by medium cut-off membranes (MCO) has been shown to be safe in maintenance hemodialysis (HD). The notion of using them for the control of chronic low-grade inflammation and positively influencing cellular immune aberrations seems tempting. We conducted an open label, multicenter, randomized, 90 day 2-phase cross over clinical trial (MCO- vs. high flux-HD). 46 patients underwent randomization of which 34 completed the study. Dialysate- or pre- and post-dialysis serum inflammatory mediators were assayed for each study visit. Ex vivo T cell activation was assessed from cryopreserved leucocytes by flow cytometry. Linear mixed models were used to compare treatment modalities, with difference in pre-dialysis serum MCP-1 levels after 3 months as the predefined primary endpoint. Filtration/dialysate concentrations of most mediators, including MCP-1 (mean ± SD: 10.5 ± 5.9 vs. 5.1 ± 3.8 pg/ml, P < 0.001) were significantly increased during MCO- versus high flux-HD. However, except for the largest mediator studied, i.e., YKL-40, this did not confer any advantages for single session elimination kinetics (post-HD mean ± SD: 360 ± 334 vs. 564 ± 422 pg/ml, P < 0.001). No sustained reduction of any of the studied mediators was found neither. Still, the long-term reduction of CD69+ (P = 0.01) and PD1+ (P = 0.02) activated CD4+ T cells was striking. Thus, MCO-HD does not induce reduction of a broad range of inflammatory mediators studied here. Long-term reduction over a 3-month period was not possible. Increased single session filtration, as evidenced by increased dialysate concentrations of inflammatory mediators during MCO-HD, might eventually be compensated for by compartment redistribution or increased production during dialysis session. Nevertheless, lasting effects on the T-cell phenotype were seen, which deserves further investigation.

Association between Inhaled β2-agonists Initiation and Risk of Major Adverse Cardiovascular Events: A Population-based Nested Case-Control Study

Purpose

Despite ample evidence underpinning the efficacy of β₂-agonists in asthma and chronic obstructive pulmonary disease (COPD), the occurrence of β₁- and β₂-adrenoceptors in the heart suggests that β₂-agonists may have deleterious cardiac effects. We investigated the association between new users of long-or short-acting β₂-agonists (LABA or SABA) or ICS (inhaled corticosteroids)/LABA and major adverse cardiovascular events (MACE).

Methods

A nested case–control analysis was conducted using the UK Clinical Practice Research Datalink of patients with asthma, COPD or asthma–COPD overlap with initial treatment of LABA, SABA, ICS/LABA, ICS, long-or short-acting muscarinic antagonist (LAMA or SAMA) between 01 January 1998 and 31 July 2018. The primary outcome was MACE, defined as the first occurrence of stroke, heart failure, myocardial infarction, arrhythmia, or cardiovascular death. Each case was matched with up to 10 controls on age, sex, date of cohort-entry, and duration of follow-up. The risk of MACE associated with β₂-agonists was estimated using conditional logistic regression after controlling for potential confounders.

Results

The cohort included 180,567 new users of β₂-agonists, ICS, SAMA, or LAMA. Among asthmatics, β₂-agonists were not associated with the risk of MACE (SABA vs ICS: HR 1.29 [0.96–1.73]; ICS/LABA vs ICS, HR 0.75 [0.33–1.73]). In contrast, among COPD patients, LABA (HR, 2.38 [1.04–5.47]), SABA (HR, 2.02 [1.13–3.59]) and ICS/LABA (HR, 2.08 [1.04–4.16]) users had an increased risk of MACE compared with SAMA users. Among patients with asthma–COPD overlap, SABA (HR, 2.57 [1.26–5.24]) was associated with an increased risk of MACE compared with ICS.

Conclusion

In conclusion, initiation of LABA, SABA, or ICS/LABA in COPD or SABA in asthma–COPD overlap is associated with increased risk of MACE. No associations were observed among patients with asthma.

Novel Biomarkers Detected by Proteomics Predict Death and Cardiovascular Events in Hemodialysis Patients

End-stage kidney disease increases mortality and the risk of cardiovascular (CV) disease. It is crucial to explore novel biomarkers to predict CV disease in the complex setting of patients receiving hemodialysis (HD). This study investigated the association between 92 targeted proteins with all-cause death, CV death, and composite vascular events (CVEs) in HD patients. From December 2010 to March 2011, 331 HD patients were included and followed prospectively for 5 years. Serum was analyzed for 92 CV-related proteins using Proseek Multiplex Cardiovascular I panel, a high-sensitivity assay based on proximity extension assay (PEA) technology. The association between biomarkers and all-cause death, CV death, and CVEs was evaluated using Cox-regression analyses. Of the PEA-based proteins, we identified 20 proteins associated with risk of all-cause death, 7 proteins associated with risk of CV death, and 17 proteins associated with risk of CVEs, independent of established risk factors. Interleukin-8 (IL-8), T-cell immunoglobulin and mucin domain 1 (TIM-1), and C-C motif chemokine 20 (CCL20) were associated with increased risk of all-cause death, CV death, and CVE in multivariable-adjusted models. Stem cell factor (SCF) and Galanin peptides (GAL) were associated with both decreased risk of all-cause death and CV death. In conclusion, IL-8, TIM-1, and CCL20 predicted death and CV outcomes in HD patients. Novel findings were that SCF and GAL were associated with a lower risk of all-cause death and CV death. The SCF warrants further study with regard to its possible biological effect in HD patients.

Cytokines and chemokines systemic levels are related to dialysis adequacy and creatinine clearance in patients with end-stage renal disease undergoing hemodialysis

Although the clearance of low-molecular weight toxins is modulated by dialysis dose, the relationship between dialysis adequacy and middle systemic inflammatory mediators is often overlooked. Thus, the relationship between dialysis adequacy, pro- and anti-inflammatory cytokines and chemokines in hemodialysis (HD) patients was investigated. Forty-eight HD patients (19 women and 25 men) were investigated. Age, body mass index, time in HD, nutritional status, Kt/V and blood biochemical parameters was similar in patients of both sexes (P > 0.05). Thus, patients were stratified by dialysis adequacy measured by Kt/V method (adequate Kt/V ≥ 1.2). Post-HD urea, creatinine, cytokines (IFN-γ, IL-4 and IL-10) and chemokines (CCL-2, CCL-5, CXCL-8 and CXCL-10) were higher in patients with Kt/V < 1.2 (P < 0.05). Kt/V exhibited significant correlation with CXCL-10/IP-10 serum levels. Positive correlation between creatinine with IFN-γ, CCL-2/MCP-1, and CXCL-10/IP-10, and negative correlation with IL-10 was identified in patients with Kt/V < 1.2 (P < 0.05). In patients with Kt/V ≥ 1.2, only IL-10 was positively and CXCL-10/IP-10 negatively correlated with creatinine levels (P < 0.05). Kt/V and creatinine levels exhibited variable predictive value (Kt/V = 27% to 37%, creatinine = 29% to 47%) to explain cytokines and chemokines circulating levels in patients with adequate and inadequate dialysis dose. Taken together, our findings provide evidence that in addition to modulating uremic toxins levels, such as urea and creatinine, dialysis dose is associated with circulating levels of inflammatory mediators. Thus, low Kt/V results and creatinine accumulation are potential indicators of the systemic inflammatory stress determined by up-regulation of proinflammatory cytokines and chemokines, and downregulation of anti-inflammatory cytokines.

The Pivotal Role of Oxidative Stress in the Pathophysiology of Cardiovascular-Renal Remodeling in Kidney Disease

The excessive activation of the renin-angiotensin system in kidney disease leads to alteration of intracellular pathways which concur altogether to the induction of cardiovascular and renal remodeling, exposing these patients since the very beginning of the renal injury to chronic kidney disease and progression to end stage renal disease, a very harmful and life threatening clinical condition. Oxidative stress plays a pivotal role in the pathophysiology of renal injury and cardiovascular-renal remodeling, the long-term consequence of its effect. This review will examine the role of oxidative stress in the most significant pathways involved in cardiovascular and renal remodeling with a focus on the detrimental effects of oxidative stress-mediated renal abnormalities on the progression of the disease and of its complications. Food for thoughts on possible therapeutic target are proposed on the basis of experimental evidences.

Interleukin-8 is increased in chronic kidney disease in children, but not related to cardiovascular disease

Introduction:

In this study, we aimed to detect the cytokine that is involved in the early stage of chronic kidney disease and associated with cardiovascular disease.

Methods:

We included 50 patients who were diagnosed with predialytic chronic kidney disease and 30 healthy pediatric patients in Ege University Medical Faculty Pediatric Clinic, İzmir/Turkey. Interleukin-8 (IL-8), interleukin-10 (IL-10), interleukin-13 (IL-13), and transforming grow factor-β1 (TGF-β1) levels (pg/mL) were measured by ELISA. Carotid-femoral pulse wave velocity (PWV), augmentation index (Aix), carotid intima media thickness (cIMT), and left ventricular mass index (LVMI) were evaluated as markers of cardiovascular disease. The presence of a cardiovascular disease marker was defined as an abnormality in any of the parameters (cIMT, PWV, Aix, and left ventricular mass index (SVKI)). The patient group was divided into two groups as with and without cardiovascular disease.

Results:

Mean Aix and PWV values were higher in CKD patients than controls (Aix: CKD 32.8±11.11%, healthy subjects: 6.74±6.58%, PWV CKD: 7.31±4.34m/s, healthy subjects: 3.42±3.01m/s, respectively; p=0.02, p=0.03). The serum IL-8 levels of CKD were significantly higher than of healthy subjects 568.48±487.35pg/mL, 33.67±47.47pg/mL, respectively (p<0.001). There was no statistically significant difference between IL-8, IL-10, IL-13, TGF-1, in CKD patients with and without cardiovascular disease (p> 0.05).

Discussion:

IL-8 is the sole cytokine that increases in pediatric patients with chronic kidney disease among other cytokines (IL-10, IL-13 and TGF-β1). However, we did not show that IL-8 is related to the presence of cardiovascular disease.

Effect of Sevelamer on Calciprotein Particles in Hemodialysis Patients: The Sevelamer Versus Calcium to Reduce Fetuin-A-Containing Calciprotein Particles in Dialysis (SCaRF) Randomized Controlled Trial

Introduction

Calciprotein particles (CPPs) are potentially modifiable mediators of phosphate toxicity in patients with kidney disease. We compared the effects of calcium carbonate (CC) and the non–calcium-based phosphate binder sevelamer on CPP levels in patients undergoing hemodialysis (HD). We hypothesized that treatment with sevelamer would achieve greater reductions in amorphous calcium phosphate–containing CPP (CPP-1) and hydroxyapatite-containing CPP (CPP-2) owing to reduced calcium loading and anti-inflammatory pleiotropic effects.

Methods

We conducted an open-label, randomized controlled trial (RCT) in which 31 stable prevalent HD patients were allocated to receive either sevelamer hydrochloride (SH), sevelamer carbonate (SC), or CC for 24 weeks. Dual primary endpoints were the between groups differences in serum CPP-1 and CPP-2 levels at 24 weeks in SH + SC–treated versus CC-treated patients. Effects on aortic pulse wave velocity (aPWV), inflammatory cytokines (interleukin-6 and -8), and effects across individual treatment arms were also assessed.

Results

Serum CPP-1, but not CPP-2, levels were lower in those randomly assigned to the sevelamer (SH + SC) group compared with the CC group at 24 weeks (–70%, 95% confidence interval [CI] –90% to –15%, P = 0.02). In subgroup analysis, this effect was confined to those receiving SC (–83.4%, 95% CI –95.7% to –36.8%, P = 0.01). aPWV and interleukin-8 levels were also lower in those who received sevelamer compared with CC at 24 weeks (–2.0 m/s, 95% CI –2.9 to –1.1; –57%, 95% CI –73% to –30%, respectively, both P = 0.01). Conventional markers of mineral metabolism remained stable across all treatment groups.

Discussion

Compared with treatment with CC, use of sevelamer for 24 weeks was associated with lower serum CPP-1 levels and a reduction in aPWV and systemic inflammation.

Endothelial cells exposed to phosphate and indoxyl sulphate promote vascular calcification through interleukin-8 secretion

BACKGROUND

Vascular calcification (VC) is amplified during chronic kidney disease, partly due to uraemic toxins such as inorganic phosphate (Pi) and indoxyl sulphate (IS) that trigger osteogenic differentiation of vascular smooth muscle cells (VSMCs). These toxins also alter endothelial cell (EC) functions but whether this contributes to VC is unknown. Here, we hypothesized that ECs exposed to Pi and IS promote VSMC calcification.

METHODS

Human umbilical vein ECs were treated with Pi, IS or both, and then the conditioned media [endothelial cell conditioned medium (EC-CM)] was collected. Human aortic SMCs (HASMCs) were exposed to the same toxins, with or without EC-CM, and then calcification and osteogenic differentiation were evaluated. Procalcifying factors secreted from ECs in response to Pi and IS were screened. Rat aortic rings were isolated to assess Pi+IS-induced calcification at the tissue level.

RESULTS

Pi and Pi+IS induced HASMCs calcification, which was significantly exacerbated by EC-CM. Pi+IS induced the expression and secretion of interleukin-8 (IL-8) from ECs. While IL-8 treatment of HASMCs stimulated the Pi+IS-induced calcification in a concentration-dependent manner, IL-8 neutralizing antibody, IL-8 receptors antagonist or silencing IL-8 gene expression in ECs before collecting EC-CM significantly prevented the EC-CM procalcifying effect. IL-8 did not promote the Pi+IS-induced osteogenic differentiation of HASMCs but prevented the induction of osteopontin (OPN), a potent calcification inhibitor. In rat aortic rings, IS also promoted Pi-induced calcification and stimulated the expression of IL-8 homologues. Interestingly, in the Pi+IS condition, IL-8 receptor antagonist lifted the inhibition of OPN expression and partially prevented aortic calcification.

CONCLUSION

These results highlight a novel role of IL-8, whose contribution to VC in the uraemic state results at least from interaction between ECs and VSMCs.

Markers of mineral metabolism and vascular access complications: The Choices for Healthy Outcomes in Caring for ESRD (CHOICE) study

INTRODUCTION

Vascular access dysfunction is a major cause of morbidity in patients with end-stage renal disease (ESRD) on chronic hemodialysis. The effects of abnormalities in mineral metabolism on vascular access are unclear. In this study, we evaluated the association of mineral metabolites, including 25-hydroxy vitamin D (25(OH)D) and fibroblast growth factor-23 (FGF-23), with vascular access complications.

METHODS

We included participants from the Choices for Healthy Outcomes in Caring for ESRD (CHOICE) Study who were using an arteriovenous fistula (AVF; n = 103) or arteriovenous graft (AVG; n = 116). Serum levels of 25(OH)D, FGF-23, parathyroid hormone (PTH), calcium, phosphorus, C-reactive protein (CRP) and interleukin-6 (IL-6) were assessed from stored samples. Participants were followed for up to 1 year or until a vascular access intervention or replacement.

FINDINGS

A total of 24 participants using an AVF and 43 participants using an AVG experienced access intervention. Those with 25(OH)D level in the lowest tertile (<11 ng/mL) had an increased risk of AVF intervention compared to those with higher 25(OH)D levels (adjusted relative hazard [aHR] = 3.28; 95% confidence interval [CI]: 1.31, 8.20). The highest tertile of FGF-23 (>3750 RU/mL) was associated with greater risk of AVF intervention (aHR = 2.56; 95% CI: 1.06, 6.18). Higher PTH was associated with higher risk of AVF intervention (aHR = 1.64 per SD of log(PTH); 95% CI: 1.02, 2.62). These associations were not observed in participants using an AVG. None of the other analytes were significantly associated with AVF or AVG intervention.

DISCUSSION

Low levels of 25(OH)D and high levels of FGF-23 and PTH are associated with increased risk of AVF intervention. Abnormalities in mineral metabolism are risk factors for vascular access dysfunction and potential therapeutic targets to improve outcomes.

Oxidative stress - chronic kidney disease - cardiovascular disease: A vicious circle

Chronic kidney disease patient's progression to end-stage renal disease as well as their high mortality are linked to cardiovascular disease. However, the high incidence rate of cardiovascular morbidity and mortality in these patients is not fully accounted for by traditional cardiovascular risk factors such as diabetes, hypertension and obesity. Renal disease and CVD are associated with endothelial dysfunction, inflammation and oxidative stress and in this review we will examine what is known regarding their similar roles in both CVD and chronic kidney disease, specifically focusing on the interconnections between oxidative stress, inflammation and endothelial dysfunction. These interconnections are best visualized as a vicious circle wherein these entities coexist and communicate with each other, thereby exacerbating the processes underpinning these different entities with the end result of the high morbidity and mortality that characterize CKD patients. By exploring this vicious circle i.e. the mode and extent of the interrelationships as well as some of the underlying mechanisms involved, this review aims at outlining our current understanding as well as highlighting future avenues for research and potential targets for therapeutic intervention.

GRHL2 Is Required for Collecting Duct Epithelial Barrier Function and Renal Osmoregulation

Collecting ducts make up the distal-most tubular segments of the kidney, extending from the cortex, where they connect to the nephron proper, into the medulla, where they release urine into the renal pelvis. During water deprivation, body water preservation is ensured by the selective transepithelial reabsorption of water into the hypertonic medullary interstitium mediated by collecting ducts. The collecting duct epithelium forms tight junctions composed of barrier-enforcing claudins and exhibits a higher transepithelial resistance than other segments of the renal tubule exhibit. However, the functional relevance of this strong collecting duct epithelial barrier is unresolved. Here, we report that collecting duct-specific deletion of an epithelial transcription factor, grainyhead-like 2 (GRHL2), in mice led to reduced expression of tight junction-associated barrier components, reduced collecting duct transepithelial resistance, and defective renal medullary accumulation of sodium and other osmolytes. In vitro, Grhl2-deficient collecting duct cells displayed increased paracellular flux of sodium, chloride, and urea. Consistent with these effects, Grhl2-deficient mice had diabetes insipidus, produced dilute urine, and failed to adequately concentrate their urine after water restriction, resulting in susceptibility to prerenal azotemia. These data indicate a direct functional link between collecting duct epithelial barrier characteristics, which appear to prevent leakage of interstitial osmolytes into urine, and body water homeostasis.

Inflammatory Cytokines as Uremic Toxins: "Ni Son Todos Los Que Estan, Ni Estan Todos Los Que Son"

Chronic kidney disease is among the fastest growing causes of death worldwide. An increased risk of all-cause and cardiovascular death is thought to depend on the accumulation of uremic toxins when glomerular filtration rate falls. In addition, the circulating levels of several markers of inflammation predict mortality in patients with chronic kidney disease. Indeed, a number of cytokines are listed in databases of uremic toxins and uremic retention solutes. They include inflammatory cytokines (IL-1β, IL-18, IL-6, TNFα), chemokines (IL-8), and adipokines (adiponectin, leptin and resistin), as well as anti-inflammatory cytokines (IL-10). We now critically review the cytokines that may be considered uremic toxins. We discuss the rationale to consider them uremic toxins (mechanisms underlying the increased serum levels and evidence supporting their contribution to CKD manifestations), identify gaps in knowledge, discuss potential therapeutic implications to be tested in clinical trials in order to make this knowledge useful for the practicing physician, and identify additional cytokines, cytokine receptors and chemokines that may fulfill the criteria to be considered uremic toxins, such as sIL-6R, sTNFR1, sTNFR2, IL-2, CXCL12, CX3CL1 and others. In addition, we suggest that IL-10, leptin, adiponectin and resistin should not be considered uremic toxins toxins based on insufficient or contradictory evidence of an association with adverse outcomes in humans or preclinical data not consistent with a causal association.

A pilot study of CXCL8 levels in crystal proven gout patients during allopurinol treatment and their association with cardiovascular disease

OBJECTIVES

Gout is associated with cardiovascular diseases, and systemic inflammation has a role in this. CXCL8 (interleukin-8) levels were increased in synovial fluid of gout patients, and in serum in gout patients irrespective of their disease activity. We hypothesized that the well-known cardiovascular protective effects of allopurinol could be related to effects of this drug on CXCL8 levels.

METHODS

Patients with a crystal proven gout diagnosis, who newly started allopurinol treatment, were included in this prospective cohort study. After evaluation at baseline for cardiovascular diseases, tophi, uric acid, CRP and CXCL8 serum levels, patients were followed for changes in uric acid and CXCL8 levels. A subgroup analysis was performed in 10 patients with the longest follow-up period and at least 4 assessments of serum uric acid and CXCL8.

RESULTS

Sixty patients were included, and patients known with cardiovascular diseases at baseline had significantly higher CXCL8 and uric acid levels (P<0.01). In the whole group, median CXCL8 levels had not decreased after a median (IQR) follow-up of 27 (12-44) weeks (P=0.66). In the subgroup analysis in 9 out of 10 patients, CXCL8 levels showed a slight decrease, sometimes after an initial increase after a median (IQR) follow-up of 51 (45-60) weeks.

CONCLUSIONS

This pilot study indicates that higher CXCL8 levels were associated cardiovascular diseases in gout patients. Short-term use of allopurinol does not decrease CXCL8 levels in gout patients, but longer use possibly does. Further studies are warranted to establish the potential mechanisms of treatment and effects on CXCL8 levels.

Gout Is a Chronic Inflammatory Disease in Which High Levels of Interleukin-8 (CXCL8), Myeloid-Related Protein 8/Myeloid-Related Protein 14 Complex, and an Altered Proteome Are Associated With Diabetes Mellitus and Cardiovascular Disease

OBJECTIVE

The frequent association of gout with metabolic syndrome and cardiovascular disease (CVD) suggests that it has a systemic component. Our objective was to study whether circulating proinflammatory cytokines are associated with comorbidities in gout patients.

METHODS

We studied 330 gout patients from 3 independent cohorts and compared them with 144 healthy individuals and 276 disease controls. We measured circulating levels of interleukin-8 (IL-8)/CXCL8, IL-1β, IL-6, IL-10, IL-12, and tumor necrosis factor, after which we performed proteome-wide analysis in a selection of samples to identify proteins that were possibly prognostic for the development of comorbidities. Replication analysis was performed specifically for myeloid-related protein 8 (MRP-8)/MRP-14 complex.

RESULTS

Compared to healthy controls and disease control patients, patients with gouty arthritis (n = 48) had significantly higher mean levels of CXCL8 (P < 0.001), while other cytokines were almost undetectable. Similarly, patients with intercritical gout showed high levels of CXCL8. CXCL8 was independently associated with diabetes mellitus in patients with intercritical gout (P < 0.0001). Proteome-wide analysis in gouty arthritis (n = 18) and intercritical gout (n = 39) revealed MRP-8 and MRP-14 as the proteins with the greatest differential expression between low and high levels of CXCL8 and also showed a positive correlation of MRP8/MRP14 complex with CXCL8 levels (R(2)  = 0.49, P < 0.001). These findings were replicated in an independent cohort. The proteome of gout patients with high levels of CXCL8 was associated with diabetes mellitus (odds ratio 16.5 [95% confidence interval 2.8-96.6]) and CVD (odds ratio 3.9 [95% confidence interval 1.0-15.3]).

CONCLUSION

Circulating levels of CXCL8 are increased during both the acute and intercritical phases of gout, and they coincide with a specific circulating proteome that is associated with risk of diabetes mellitus and CVD. Further research focused on the roles of CXCL8 and MRP8/MRP14 complex in patients with gout is warranted.

Inflammation in coronary artery disease

Coronary artery disease (CAD) is the leading cause of death in the United States. Although CAD was formerly considered a lipid accumulation-mediated disease, it has now been clearly shown to involve an ongoing inflammatory response. Advances in basic science research have established the crucial role of inflammation in mediating all stages of CAD. Today, there is convincing evidence that multiple interrelated immune mechanisms interact with metabolic risk factors to initiate, promote, and ultimately activate lesions in the coronary arteries. This review aims to provide current evidence pertaining to the role of inflammation in the pathogenesis of CAD and discusses the impact of inflammatory markers and their modification on clinical outcomes.

Interleukin-8 is associated with increased total mortality in women but not in men-findings from a community-based cohort of elderly

OBJECTIVE

To elucidate the association among circulating IL-8 and total mortality in a cohort of elderly, and to explore potential sex differences in the observed association.

METHODS

The Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) is a cohort of 70-year-old men and women living in Uppsala, Sweden; baseline period: 2001-2004. IL-8 serum measurements were performed in 1003 participants.

RESULTS

In total, 61 men and 40 women died during follow-up (median 7.9 years). Baseline IL-8 concentrations were higher in women than in men (P = 0.03). In a multivariable model adjusting for age, established cardiovascular risk factors, and C-reactive protein, log-transformed standard deviation increments in IL-8 levels were weakly associated with an increased risk for total mortality (hazard ratio (HR) 1.12, 95% confidence interval (CI) 1.02-1.23, P < 0.05) in the whole cohort. Stratified analysis revealed an association in women (HR 1.18, 95% CI 1.06-1.30, P < 0.01) but not in men (HR 0.98, 95% CI 0.76-1.26).

CONCLUSIONS

A weak association between IL-8 serum levels and an increased risk for mortality was observed. The prospective data support the role of IL-8 as a biomarker of interest; yet, further studies are warranted to elucidate validity of our finding and the possibility of a sex difference.

Microinflammation factors in the common diseases of the heart and kidneys

Aim. To determine levels of interleukin-8 (IL-8) and plasminogen activator inhibitor-1 (PAI-1) in different cardiorenal syndrome (CRS) modalities and to compare findings to some already investigated direct and indirect parameters of inflammation and atherosclerosis. Materials and Methods. Testing involved 114 examinees, divided into control and clinical groups suffering from different modalities and were formed according to the basis of a valid classification for CRS. Results. C-reactive protein (CRP) was significantly higher in all CRSs in comparison to the control group (P < 0.05). PAI-1 in CRSs was statistically higher than in the control group. IL-8 was increased in all CRSs, and especially in CRS-5, where no significance was found. PAI-1 correlated with IL-8 in all CRSs, with significant value in CRS-2 and CRS-5. Correlation for PAI-1 and high-density lipoproteins (HDL) was found in CRS-4, while IL-8 was found to be related to CRP level in all CRSs, with significance only in CRS-1 (P < 0.001). Conclusions. C-reactive protein, IL-8, and PAI-1 could be useful for clinical differentiation of chronic modalities of CRSs. Inflammation was the most pronounced in CRS-4. Lipid status parameters could be useful for differentiation of CRSs. Furthermore, HDL in chronic primary kidney diseases and triglycerides and total cholesterol in CRS-5 could be valuable.

Effects of alpha lipoic acid supplementation on serum levels of IL-8 and TNF-α in patient with ESRD undergoing hemodialysis

BACKGROUND

Chronic renal failure is a progressive and irreversible loss of kidney function, and the hemodialysis (HD) is one of the most common modalities in this regard. Oxidative stresses [like interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α)] and inflammation are the main risk factors associated with cardiovascular diseases and other complications in many organs in hemodialysis patients; meanwhile, antioxidants like alpha lipoic acid (ALA) may reduce the oxidative stress markers and the levels of inflammatory cytokines, so can improve of the patient's quality of life.

METHODS

In this randomized clinical trial study, 60 HD patients were randomly categorized in two case and control groups. Case group received a daily capsule of 600 mg of ALA supplementation for 8 weeks, and the control group received placebo capsules daily. The serum level of IL-8 and TNF-α was measured in both groups before and after the intervention.

RESULTS

There were no significant differences in age, gender, duration of dialysis, and causative factor for dialysis between both groups (P > 0.05). The mean of IL-8 and TNF-α after the intervention in case group was 26.20 ± 15.34 and 21.25 ± 9.61, respectively; the difference between both groups was not statistically significant (P > 0.05).

CONCLUSION

Based on the better feeling and other beneficial effects of ALA were found in our study; we can conclude that it is a beneficial and recommended supplement, especially, for diabetic and dialysis patients.

ROL' tsITOKINOV V RAZVITII SERDEChNO-SOSUDISTyKh ZABOLEVANIY I OSTEOPOROZA

At thepresent time there is a great interest in médical researche devoted to investigation the role of cytokines (interleukins) in the pathogenesis of cardiovascular diseases (atherosclerosis, arterial hypertension, ischemic heart disease, etc.), and osteoporosis. The review provides data on the conducted research on the importance of cytokines in the event of these diseases.

Investigation of skeletal muscle quantity and quality in end-stage renal disease

AIM

A more precise understanding of the aetiology and sequelae of muscle wasting in end-stage renal disease (ESRD) is required for the development of effective interventions to target this pathology.

METHODS

We investigated 49 patients with ESRD (62.6 +/- 14.2 years, 0.3-16.7 years on haemodialysis). Thigh muscle cross-sectional area (CSA), intramuscular lipid and intermuscular adipose tissue (IMAT) were measured via computed tomography as indices of muscle quantity (i.e. CSA) and quality (i.e. intramuscular lipid and IMAT). Additional health and clinical measures were investigated to determine associations with these variables.

RESULTS

Age, energy intake, disease burden, pro-inflammatory cytokines, nutritional status, strength and functioning were related to muscle quantity and quality. Potential aetiological factors entered into forward stepwise regression models indicated that hypoalbuminaemia and lower body mass index accounted significantly and independently for 32% of the variance in muscle CSA (r = 0.56, P < 0.001), while older age and interleukin-8 accounted for 41% of the variance in intramuscular lipid (r = 0.64, P < 0.001) and body mass index accounted for 45% of the variance in IMAT (r = 0.67, P < 0.001). Stepwise regression models revealed that intramuscular lipid was independently predictive of habitual gait velocity and 6 min walk distance, while CSA was independently predictive of maximal isometric strength (P < 0.05).

CONCLUSION

Ageing, poor nutritional status and elevated interleukin-8 are factors potentially contributing to the loss of muscle quality and quantity in ESRD. These deficits can predict functional impairments, with intramuscular lipid accumulation most closely related to decline of submaximal musculoskeletal performance (walking), and low muscle CSA most closely related to decline of maximal performance (peak isometric strength).

Elastase, α1-proteinase inhibitor, and interleukin-8 in pre-dialyzed and hemodialyzed patients with chronic kidney disease

BACKGROUND

Neutrophil elastase in complex with α(1) -proteinase inhibitor (NE-α(1) PI) and interleukin (IL)-8 may serve as indicators of neutrophil activation and inflammatory stage. The aim of the study was to evaluate NE-α(1) PI, α(1)-PI, and IL-8 levels in the blood of patients with chronic kidney disease (CKD) undergoing hemodialysis (HD) or conservatively treated (CT). The influence of a single HD session on the investigated parameters was also assessed.

METHODS

Blood samples were obtained from two groups of hemodialyzed patients (children/young adults [group HD1, n = 8] and adults [group HD2, n = 13]), as well as 13 CT patients and a group of healthy subjects. The proteins were measured using enzyme-linked immunosorbent assay or radial immunodiffusion.

RESULTS

There were no significant differences in NE-α(1) PI, α(1)-PI, and IL-8 concentrations between the HD1 and HD2 patients. The levels of NE-α(1) PI were considerably higher than normal in both groups of HD patients (before and after the HD session) and in the CT patients. Higher titers of NE-α(1) PI (P < 0.05) and α(1)-PI (P < 0.01) were obtained in the adults during the course of HD. Increased NE-α(1) PI was positively correlated with α(1)-PI. The serum concentration of IL-8 was significantly higher in the HD2 patients before and after dialysis than in the controls.

CONCLUSIONS

The data indicate that in CKD patients, neutrophils are highly activated both in the pre-dialyzed period and on regular HD. Contact with the dialysis membrane during HD causes a significant increase in blood NE-α(1) PI and α(1)-PI in adults, but not in children/young adults. NE-α(1) PI seems to be a much better indicator of an inflammatory state in CKD patients than free α(1)-PI or IL-8.

Cholecalciferol supplementation alters calcitriol-responsive monocyte proteins and decreases inflammatory cytokines in ESRD

In vitro, monocyte 1alpha-hydroxylase converts 25-hydroxyvitamin D [25(OH)D] to 1,25-dihydroxyvitamin D to regulate local innate immune responses, but whether 25(OH)D repletion affects vitamin D-responsive monocyte pathways in vivo is unknown. Here, we identified seven patients who had 25(OH)D insufficiency and were undergoing long-term hemodialysis and assessed changes after cholecalciferol and paricalcitol therapies in both vitamin D-responsive proteins in circulating monocytes and serum levels of inflammatory cytokines. Cholecalciferol therapy increased serum 25(OH)D levels four-fold, monocyte vitamin D receptor expression three-fold, and 24-hydroxylase expression; therapy decreased monocyte 1alpha-hydroxylase levels. The CD16(+) "inflammatory" monocyte subset responded to 25(OH)D repletion the most, demonstrating the greatest increase in vitamin D receptor expression after cholecalciferol. Cholecalciferol therapy reduced circulating levels of inflammatory cytokines, including IL-8, IL-6, and TNF. These data suggest that nutritional vitamin D therapy has a biologic effect on circulating monocytes and associated inflammatory markers in patients with ESRD.

Review article: Tackling the survival issue in end-stage renal disease: time to get physical on haemodialysis

Life expectancy in haemodialysis patients is reduced fourfold on average versus healthy age-matched individuals. The purpose of this review is to present empirical evidence that intradialytic exercise can mitigate primary independent risk factors for early mortality in end-stage renal disease. These risk factors include measures of skeletal muscle wasting, systemic inflammation, cardiovascular functioning and dialysis adequacy. Overall, the available literature provides support for the integration of exercise within the conventional outpatient haemodialysis unit. The amelioration of various physiological risk factors through an appropriate exercise prescription may enhance survival in this vulnerable cohort. Investigations are required to determine the effects of various doses of intradialytic exercise on a broad range of clinical outcomes, and more thoroughly elucidate the relationship between exercise-induced adaptations and survival advantage in end-stage renal disease.

Cytokine dysregulation in chronic kidney disease: how can we treat it?

As the kidney is the major site for elimination of many cytokines, the delicate equilibrium of pro-inflammatory cytokines and their inhibitors is clearly dysregulated in chronic kidney disease (CKD) patients. The consequences of the altered immune response in uremia lead to a state of persistent inflammation which is highly prevalent among CKD patients and is linked to complications such as the development of protein-energy wasting and atherosclerotic vascular disease. The present review aims at reviewing this complex orchestration of uremic cytokines beyond the well-studied interleukin-6 and tumor necrosis factor-alpha. Finally, we update our current understanding on anti-inflammatory treatment strategies in CKD patients, including nutritional and lifestyle measurements, pharmacological intervention and specific anticytokine strategies targeting the dialytic procedure.

Simvastatin and fluvastatin reduce interleukin-6 and interleukin-8 lipopolysaccharide (LPS) stimulated production by isolated human monocytes from chronic kidney disease patients

BACKGROUND

Statins reduce lipid levels, inflammation and cardiovascular events in patients with coronary artery disease; CKD patients show increased risk of cardiovascular and increased plasma levels of IL-6 and IL-8.

AIM

To evaluate the in vitro effect of simvastatin (S) or fluvastatin (F) on the lipopolysaccharide (LPS) stimulated secretion of IL-6 and IL-8 from monocytes of chronic kidney disease patients (CKD) in K-DOQI stages 3-5.

METHODS AND SUBJECTS

Monocytes enriched peripheral blood (PBMC) from 28 CKD (15 in K-DOQI stages 3-4, Group I, and 13 in K-DOQI stage 5 on hemodialysis, Group II) and 10 healthy subjects (HS), were isolated by Ficoll-gradient centrifugation. Cells were incubated with LPS 100 ng/ml or with LPS plus increasing doses of statins (from 10(-6) to 10(-8) M ) for 24 h. Surnatant IL-6 and IL-8 concentrations were determined by EIA.

RESULTS

Basally the mean concentration of IL-6 and IL-8 was higher in patients than in HS and in Group II than in Group I (IL6: HS 285 +/- 77 pg/ml, Group I 365 +/- 178 pg/ml, Group II 520 +/- 139 pg/ml- IL8 HS 180 +/- 75 pg/ml, Group I 1722 +/- 582 pg/ml, Group II 4400 +/- 1935 pg/ml). After addition of LPS the mean concentration of IL-6 and IL-8 increased in all groups (IL6: HS 1740 +/- 178 pg/ml, Group I 3754 +/- 672 pg/ml, Group II 4800 +/- 967 pg/ml; IL8: HS 450+/-132 pg/ml, Group I 9700+/-2837 pg/ml, Group II 11608 +/- 2316 pg/ml). After the addition of LPS plus increasing doses of S or F from 10(-10) to 10(-6) M, a significantly lower cytokine concentration compared to the data after LPS alone was observed (IL6: HS 45%, Group I 75%, Group II 50%; IL8: HS 100%, Group I 65%, Group II 35%).

CONCLUSIONS

These data confirm that cytokine release is increased in CKD patients and that is highest in the most severe patients. Furthermore they suggest that fluvastatin or simvastatin can be used in order to reduce the high cardiovascular risk.

Cardiovascular Biomarkers in CKD: Pathophysiology and Implications for Clinical Management of Cardiac Disease

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with all forms of chronic kidney disease (CKD). The underlying pathological state is caused by a complex interplay of traditional and nontraditional risk factors that results in atherosclerosis, arteriosclerosis, and altered cardiac morphological characteristics. This multifactorial disease introduces new challenges in predicting and treating patients with CVD sufficiently early in the course of CKD to positively alter patient outcome. Asymptomatic individuals with progressive CVD are a group of patients that deserve focused attention because early detection and intervention may provide the best opportunity for improved outcome. However, identifying CVD in asymptomatic patients with CKD or end-stage renal disease remains a significant hurdle in the management of these patients. Recently, a number of cardiovascular biomarkers were identified as predictors of patient outcome in individuals with CVD and, with additional research, may be used to guide the early diagnosis of and therapy for CVD in patients with CKD. This review examines the pathophysiological characteristics and potential clinical role of these novel cardiovascular biomarkers in risk stratification, risk monitoring, and selection of preventive therapies for patients with CKD.

Epidemiology of dialysis patients and heart failure patients

The epidemiology of maintenance dialysis patients and heart failure patients has striking similarities. Both groups have a high prevalence of comorbid conditions, a high hospitalization rate, a low self-reported quality of life, and an excessively high mortality risk, mostly because of cardiovascular causes. Observational studies in both dialysis and heart failure patients have indicated the lack of a significant association between the traditional cardiovascular risk factors and mortality, or the existence of a paradoxic or reverse association, in that obesity, hypercholesterolemia, and hypertension appear to confer survival advantages. The time discrepancy between the 2 sets of risk factors, that is, overnutrition (long-term killer) versus undernutrition (short-term killer) may explain the overwhelming role of malnutrition, inflammation, and cachexia in causing the reverse epidemiology, which may exist in more than 20 million Americans. We have reviewed the opposing views about the concept of reverse epidemiology in dialysis and heart failure patients, the recent Die Deutsche Diabetes Dialyze study findings, and the possible role of racial disparities. Contradictory findings on hyperhomocysteinemia in dialysis patients are reviewed in greater details as a possible example of publication bias. Additional findings related to intravenous iron and serum ferritin, calcium, and leptin levels in dialysis patients may enhance our understanding of the new paradigm. The association between obesity and increased death risk in kidney transplanted patients is reviewed as an example of the reversal of reverse epidemiology. Studying the epidemiology of dialysis patients as the archetypical population with such paradoxic associations may lead to the development of population-specific guidelines and treatment strategies beyond the current Framingham cardiovascular risk factor paradigm.