Gender-specific risk factors and outcomes of hyperkalemia in CKD patients: smoking as a driver of hyperkalemia in men.

Background: Hyperkalemia is common among patients with chronic kidney disease (CKD) but there is scarce information on differential risk factors and outcomes for men and women. For instance, smoking has been suggested to be a risk factor for hyperkalemia, but specific analysis of the sex-specific impact of smoking on hyperkalemia in CKD is lacking. Methods: We studied serum potassium levels in 2891 participants from the NEFRONA cohort: 483 controls (47% women) and 2408 CKD patients (38% women) without prior cardiovascular disease (CVD), assessing whether smoking is a risk factor for hyperkalemia, and if hyperkalemia is associated with outcomes separately for men and women. Results: Median potassium levels and prevalence of hypo and hyperkalemia were higher in CKD participants than in controls. Serum potassium levels were higher and hyperkalemia and severe hyperkalemia more prevalent in men than in women with non-dialysis CKD (G3-G5). The highest prevalence of hyperkalemia for each gender was found in CKD G4-G5 and hemodialysis patients for men (46%) and in hemodialysis (54%) for women. Gender-specific etiological multivariate analysis identified current smoking as a risk factor for hyperkalemia only in men. Hyperkalemia was independently associated with stopping RAASi, an outcome which was more common in women. Hyperkalemia was also associated to higher risk of cardiovascular events within 4 years in men. In conclusion, hyperkalemia is common among men and women with CKD, but the prevalence, risk factors and outcomes may differ by gender. Specifically, current smoking is a driver of hyperkalemia in men.

Advanced lipoprotein parameters could better explain atheromatosis in non-diabetic chronic kidney disease patients.

BACKGROUND: Chronic kidney disease (CKD) patients have a high burden of atheromatous cardiovascular disease (ASCVD) not fully explained by traditional lipid parameters. Lipoprotein composition and subclass particle number information could improve ASCVD risk assessment. The objective of this study is to investigate the association of advanced lipoprotein parameters with the risk of atheromatosis in a subpopulation of the NEFRONA study. METHODS: This was a cross-sectional study in 395 non-diabetic individuals (209 CKD and 186 non-diabetic and non-CKD) without statin therapy. Vascular ultrasound examination assessing 10 territories was combined with advanced lipoprotein testing performed by nuclear magnetic resonance spectroscopy. Logistic regression was used to estimate adjusted odds ratios (ORs) per 1 standard deviation increment. RESULTS: Atheromatosis was more prevalent in CKD patients (33.9% versus 64.6%). After adjusting for age, gender, smoking habit and CKD stage, the amount of triglycerides (TGs) within low-density lipoprotein (LDL) lipoproteins was independently and positively associated with atheromatosis [OR 1.33; 95% confidence interval (CI) 1.03-1.74; P = 0.03]. Similarly, total and medium LDL particles (LDL-Ps) showed a positive association (OR 1.29; 95% CI 1.00-1.68; P = 0.05 and OR 1.34; 95% CI 1.04-1.75; P = 0.03, respectively). TG-loaded medium LDL-Ps were higher in CKD patients compared with controls and showed an adjusted OR of 1.40 (95% CI 1.09-1.82; P = 0.01) in non-diabetic patients (CKD and non-CKD individuals). In contrast, non-diabetic CKD patients showed a similar coefficient but the significance was lost (OR 1.2; 95% CI 0.8-1.7; P = 0.359). CONCLUSIONS: Non-diabetic CKD patients showed a higher amount of TG-loaded medium LDL-Ps compared with controls. These particles were independently associated with atheromatosis in non-diabetic patients.

Circulating CD5L is associated with cardiovascular events and all-cause mortality in individuals with chronic kidney disease.

This study assessed the association of CD5L and soluble CD36 (sCD36) with the risk of a cardiovascular event (CVE), including CV death and all-cause mortality in CKD. We evaluated the association of CD5L and sCD36 with a predefined composite CV endpoint (unstable angina, myocardial infarction, transient ischemic attack, cerebrovascular accident, congestive heart failure, arrhythmia, peripheral arterial disease [PAD] or amputation by PAD, aortic aneurysm, or death from CV causes) and all-cause mortality using Cox proportional hazards regression, adjusted for CV risk factors. The analysis included 1,516 participants free from pre-existing CV disease followed up for 4 years. The median age was 62 years, 38.8% were female, and 26.8% had diabetes. There were 98 (6.5%) CVEs and 72 (4.8%) deaths, of which 26 (36.1%) were of CV origin. Higher baseline CD5L concentration was associated with increased risk of CVE (HR, 95% CI, 1.17, 1.0-1.36), and all-cause mortality (1.22, 1.01-1.48) after adjusting for age, sex, diabetes, systolic blood pressure, dyslipidemia, waist circumference, smoking, and CKD stage. sCD36 showed no association with adverse CV outcomes or mortality. Our study showed for the first time that higher concentrations of CD5L are associated with future CVE and all-cause mortality in individuals with CKD.

Intravenous iron therapy and the cardiovascular system: risks and benefits.

Anaemia is a common complication of chronic kidney disease (CKD). In this setting, iron deficiency is frequent because of the combination of increased iron needs to sustain erythropoiesis with increased iron losses. Over the years, evidence has accumulated on the involvement of iron in influencing pulmonary vascular resistance, endothelial function, atherosclerosis progression and infection risk. For decades, iron therapy has been the mainstay of therapy for renal anaemia together with erythropoiesis-stimulating agents (ESAs). Despite its long-standing use, grey areas still surround the use of iron therapy in CKD. In particular, the right balance between either iron repletion with adequate therapy and the avoidance of iron overload and its possible negative effects is still a matter of debate. This is particularly true in patients having functional iron deficiency. The recent Proactive IV Iron Therapy in Haemodialysis Patients trial supports the use of intravenous (IV) iron therapy until a ferritin upper limit of 700 ng/mL is reached in haemodialysis patients on ESA therapy, with short dialysis vintage and minimal signs of inflammation. IV iron therapy has also been proven to be effective in the setting of heart failure (HF), where it improves exercise capacity and quality of life and possibly reduces the risk of HF hospitalizations and cardiovascular deaths. In this review we discuss the risks of functional iron deficiency and the possible benefits and risks of iron therapy for the cardiovascular system in the light of old and new evidence.

Extracellular Vesicles and Renal Fibrosis: An Odyssey toward a New Therapeutic Approach.

Renal fibrosis is a complex disorder characterized by the destruction of kidney parenchyma. There is currently no cure for this devastating condition. Extracellular vesicles (EVs) are membranous vesicles released from cells in both physiological and diseased states. Given their fundamental role in transferring biomolecules to recipient cells and their ability to cross biological barriers, EVs have been widely investigated as potential cell-free therapeutic agents. In this review, we provide an overview of EVs, focusing on their functional role in renal fibrosis and signaling messengers responsible for EV-mediated crosstalk between various renal compartments. We explore recent findings regarding the renoprotective effect of EVs and their use as therapeutic agents in renal fibrosis. We also highlight advantages and future perspectives of the therapeutic applications of EVs in renal diseases.

Risk factors associated with valvular calcification in patients with chronic kidney disease. Analysis of NEFRONA study.

INTRODUCTION: Patients with chronic kidney disease (CKD) are at high risk of cardiovascular morbidity and mortality. Subclinical cardiac structural alterations have prognostic value in these patients. The aim was to analyse the prevalence of valvular calcification, the evolution and the relationship with different risk factors. MATERIAL AND METHODS: Part of the sample of the NEFRONA study was randomly selected. Aortic and mitral valve calcification were analysed in echocardiograms performed at the baseline visit and at 24 months. RESULTS: We included 397 patients, the estimated basal glomerular filtrate (eGFR) was 33 ml/min with significant decrease to 30.9 ml/min. There was an increase in the area of carotid and femoral plaque, as well as an increase in patients with aortic and mitral calcification at 24 months. A positive association of mitral calcification at 24 months with age, ankle-brachial index (ABI) and calcium-phosphorus product (CaxP) at baseline visit was observed, without association with eGFR. Aortic calcification at 24 months was positively associated with age, phosphorous and total carotid plaque area at baseline, with no relationship to eGFR. CONCLUSIONS: A significant prevalence of valvular calcification was observed in patients with CKD without known cardiovascular disease.Two-year progression was observed independently of the eGFR. Patients with higher risk of mitral valve calcification were those with older age, higher ABI and CaxP product. Patients with a higher risk of aortic calcification were those with older age, higher phosphorous levels and larger area of carotid plaque. Identifying these higher risk patients would help to avoid future cardiovascular events intensifying follow-ups.

[Risk factors associated with valvular calcification in patients with chronic kidney disease. Analysis of NEFRONA Study]. / Factores de riesgo asociados a la calcificación valvular en pacientes con enfermedad renal crónica. Análisis del Estudio Nefrona.

INTRODUCTION: Patients with chronic kidney disease (CKD) are at high risk of cardiovascular morbidity and mortality. Subclinical cardiac structural alterations have prognostic value in these patients. The aim was to analyse the prevalence of valvular calcification, the evolution and the relationship with different risk factors. MATERIAL AND METHODS: Part of the sample of the NEFRONA study was randomly selected. Aortic and mitral valve calcification were analysed in echocardiograms performed at the baseline visit and at 24 months. RESULTS: We included 397 patients, the estimated basal glomerular filtrate (eGFR) was 33ml/min with significant decrease to 30.9ml/min. There was an increase in the area of carotid and femoral plaque, as well as an increase in patients with aortic and mitral calcification at 24 months. A positive association of mitral calcification at 24 months with age, ankle-brachial index (ABI) and calcium-phosphorus product (CaxP) at baseline visit was observed, without association with eGFR. Aortic calcification at 24 months was positively associated with age, phosphorous and total carotid plaque area at baseline, with no relationship to eGFR. CONCLUSIONS: A significant prevalence of valvular calcification was observed in patients with CKD without known cardiovascular disease.Two-year progression was observed independently of the eGFR. Patients with higher risk of mitral valve calcification were those with older age, higher ABI and CaxP product. Patients with a higher risk of aortic calcification were those with older age, higher phosphorous levels and larger area of carotid plaque. Identifying these higher risk patients would help to avoid future cardiovascular events intensifying follow-ups.

Conversion of Urine Protein-Creatinine Ratio or Urine Dipstick Protein to Urine Albumin-Creatinine Ratio for Use in Chronic Kidney Disease Screening and Prognosis : An Individual Participant-Based Meta-analysis.

BACKGROUND: Although measuring albuminuria is the preferred method for defining and staging chronic kidney disease (CKD), total urine protein or dipstick protein is often measured instead. OBJECTIVE: To develop equations for converting urine protein-creatinine ratio (PCR) and dipstick protein to urine albumin-creatinine ratio (ACR) and to test their diagnostic accuracy in CKD screening and staging. DESIGN: Individual participant-based meta-analysis. SETTING: 12 research and 21 clinical cohorts. PARTICIPANTS: 919 383 adults with same-day measures of ACR and PCR or dipstick protein. MEASUREMENTS: Equations to convert urine PCR and dipstick protein to ACR were developed and tested for purposes of CKD screening (ACR ≥30 mg/g) and staging (stage A2: ACR of 30 to 299 mg/g; stage A3: ACR ≥300 mg/g). RESULTS: Median ACR was 14 mg/g (25th to 75th percentile of cohorts, 5 to 25 mg/g). The association between PCR and ACR was inconsistent for PCR values less than 50 mg/g. For higher PCR values, the PCR conversion equations demonstrated moderate sensitivity (91%, 75%, and 87%) and specificity (87%, 89%, and 98%) for screening (ACR >30 mg/g) and classification into stages A2 and A3, respectively. Urine dipstick categories of trace or greater, trace to +, and ++ for screening for ACR values greater than 30 mg/g and classification into stages A2 and A3, respectively, had moderate sensitivity (62%, 36%, and 78%) and high specificity (88%, 88%, and 98%). For individual risk prediction, the estimated 2-year 4-variable kidney failure risk equation using predicted ACR from PCR had discrimination similar to that of using observed ACR. LIMITATION: Diverse methods of ACR and PCR quantification were used; measurements were not always performed in the same urine sample. CONCLUSION: Urine ACR is the preferred measure of albuminuria; however, if ACR is not available, predicted ACR from PCR or urine dipstick protein may help in CKD screening, staging, and prognosis. PRIMARY FUNDING SOURCE: National Institute of Diabetes and Digestive and Kidney Diseases and National Kidney Foundation.

Adiposity and risk of decline in glomerular filtration rate: meta-analysis of individual participant data in a global consortium.

OBJECTIVE: To evaluate the associations between adiposity measures (body mass index, waist circumference, and waist-to-height ratio) with decline in glomerular filtration rate (GFR) and with all cause mortality. DESIGN: Individual participant data meta-analysis. SETTING: Cohorts from 40 countries with data collected between 1970 and 2017. PARTICIPANTS: Adults in 39 general population cohorts (n=5 459 014), of which 21 (n=594 496) had data on waist circumference; six cohorts with high cardiovascular risk (n=84 417); and 18 cohorts with chronic kidney disease (n=91 607). MAIN OUTCOME MEASURES: GFR decline (estimated GFR decline ≥40%, initiation of kidney replacement therapy or estimated GFR <10 mL/min/1.73 m2) and all cause mortality. RESULTS: Over a mean follow-up of eight years, 246 607 (5.6%) individuals in the general population cohorts had GFR decline (18 118 (0.4%) end stage kidney disease events) and 782 329 (14.7%) died. Adjusting for age, sex, race, and current smoking, the hazard ratios for GFR decline comparing body mass indices 30, 35, and 40 with body mass index 25 were 1.18 (95% confidence interval 1.09 to 1.27), 1.69 (1.51 to 1.89), and 2.02 (1.80 to 2.27), respectively. Results were similar in all subgroups of estimated GFR. Associations weakened after adjustment for additional comorbidities, with respective hazard ratios of 1.03 (0.95 to 1.11), 1.28 (1.14 to 1.44), and 1.46 (1.28 to 1.67). The association between body mass index and death was J shaped, with the lowest risk at body mass index of 25. In the cohorts with high cardiovascular risk and chronic kidney disease (mean follow-up of six and four years, respectively), risk associations between higher body mass index and GFR decline were weaker than in the general population, and the association between body mass index and death was also J shaped, with the lowest risk between body mass index 25 and 30. In all cohort types, associations between higher waist circumference and higher waist-to-height ratio with GFR decline were similar to that of body mass index; however, increased risk of death was not associated with lower waist circumference or waist-to-height ratio, as was seen with body mass index. CONCLUSIONS: Elevated body mass index, waist circumference, and waist-to-height ratio are independent risk factors for GFR decline and death in individuals who have normal or reduced levels of estimated GFR.

Combination of biomarkers of vascular calcification and sTWEAK to predict cardiovascular events in chronic kidney disease.

BACKGROUND AND AIMS: Vascular calcification (VC) and atherosclerosis are associated with an increased cardiovascular morbimortality in chronic kidney disease (CKD). Osteoprotegerin (OPG) and osteopontin (OPN) are involved in both VC and CKD. Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) has been related to cardiovascular disease. We hypothesized that OPG, OPN and sTWEAK levels may be associated with a higher prevalence of cardiovascular outcomes in patients with CKD. METHODS: The presence of calcified or non-calcified atherosclerotic plaques was assessed in 1043 stage 3 to 5D CKD patients from The NEFRONA Study. Biochemical measurements and OPG, OPN and sTWEAK serum levels were analyzed. Patients were followed for cardiovascular outcomes (41 ±â€¯16 months). RESULTS: At recruitment, 26% of CKD patients had VC. The adjusted odds ratios for having VC were 2.22 (1.32-3.75); p=.003 for OPG, and 0.45 (0.24-0.84); p=.01 for sTWEAK concentrations. After follow-up, 95 CV events occurred. In a Cox model, patients with OPG or OPN above and sTWEAK below their optimal cut-off points had an adjusted higher risk of cardiovascular events [HR: 2.10 (1.49-3.90); p=.02; 1.65 (1.02-2.65); p=.04; 2.05 (1.28-3.29), p=.003; respectively]. When CKD patients were grouped according to the number of biomarkers above (OPG and OPN) or below (sTWEAK) their cut-off points, the combination of these biomarkers showed the highest risk for cardiovascular events [HR: 9.46 (3.80-23.5) p < .001]. A composite score of these three biomarkers increased the C-statistic and net reclassification index beyond conventional risk factors and VC. CONCLUSIONS: The combination of OPG, OPN and sTWEAK increased the predictability of cardiovascular outcomes.

Role of Epidermal Growth Factor Receptor (EGFR) and Its Ligands in Kidney Inflammation and Damage.

Chronic kidney disease (CKD) is characterized by persistent inflammation and progressive fibrosis, ultimately leading to end-stage renal disease. Although many studies have investigated the factors involved in the progressive deterioration of renal function, current therapeutic strategies only delay disease progression, leaving an unmet need for effective therapeutic interventions that target the cause behind the inflammatory process and could slow down or reverse the development and progression of CKD. Epidermal growth factor receptor (EGFR) (ERBB1), a membrane tyrosine kinase receptor expressed in the kidney, is activated after renal damage, and preclinical studies have evidenced its potential as a therapeutic target in CKD therapy. To date, seven official EGFR ligands have been described, including epidermal growth factor (EGF) (canonical ligand), transforming growth factor-α, heparin-binding epidermal growth factor, amphiregulin, betacellulin, epiregulin, and epigen. Recently, the connective tissue growth factor (CTGF/CCN2) has been described as a novel EGFR ligand. The direct activation of EGFR by its ligands can exert different cellular responses, depending on the specific ligand, tissue, and pathological condition. Among all EGFR ligands, CTGF/CCN2 is of special relevance in CKD. This growth factor, by binding to EGFR and downstream signaling pathway activation, regulates renal inflammation, cell growth, and fibrosis. EGFR can also be "transactivated" by extracellular stimuli, including several key factors involved in renal disease, such as angiotensin II, transforming growth factor beta (TGFB), and other cytokines, including members of the tumor necrosis factor superfamily, showing another important mechanism involved in renal pathology. The aim of this review is to summarize the contribution of EGFR pathway activation in experimental kidney damage, with special attention to the regulation of the inflammatory response and the role of some EGFR ligands in this process. Better insights in EGFR signaling in renal disease could improve our current knowledge of renal pathology contributing to therapeutic strategies for CKD development and progression.

The PDK1 Inhibitor Dichloroacetate Controls Cholesterol Homeostasis Through the ERK5/MEF2 Pathway.

Controlling cholesterol levels is a major challenge in human health, since hypercholesterolemia can lead to serious cardiovascular disease. Drugs that target carbohydrate metabolism can also modify lipid metabolism and hence cholesterol plasma levels. In this sense, dichloroacetate (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, augments usage of the glycolysis-produced pyruvate in the mitochondria increasing oxidative phosphorylation (OXPHOS). In several animal models, DCA decreases plasma cholesterol and triglycerides. Thus, DCA was used in the 70 s to treat diabetes mellitus, hyperlipoproteinemia and hypercholesterolemia with satisfactory results. However, the mechanism of action remained unknown and we describe it here. DCA increases LDLR mRNA and protein levels as well as LDL intake in several cell lines, primary human hepatocytes and two different mouse models. This effect is mediated by transcriptional activation as evidenced by H3 acetylation on lysine 27 on the LDLR promoter. DCA induces expression of the MAPK ERK5 that turns on the transcription factor MEF2. Inhibition of this ERK5/MEF2 pathway by genetic or pharmacological means decreases LDLR expression and LDL intake. In summary, our results indicate that DCA, by inducing OXPHOS, promotes ERK5/MEF2 activation leading to LDLR expression. The ERK5/MEF2 pathway offers an interesting pharmacological target for drug development.

Soluble TWEAK and atheromatosis progression in patients with chronic kidney disease.

BACKGROUND AND AIMS: Circulating soluble TNF-like weak inducer of apoptosis (sTWEAK) concentrations are related to the presence of chronic kidney disease (CKD) and cardiovascular disease (CVD). However, there are no data regarding the potential association between sTWEAK and atheromatosis progression in patients free of cardiovascular events. METHODS: Soluble TWEAK serum concentration was measured in 702 CKD patients without any previous CV event from The National Observatory of Atherosclerosis in Nephrology (NEFRONA) Study. B-mode ultrasound was performed to detect the presence of carotid and/or femoral atherosclerotic plaques. The association between sTWEAK levels, atherosclerotic burden (number of plaques) and atheromatosis progression (increase in the number of plaques) after 24 months of follow-up was analyzed. RESULTS: A continuous decrease in sTWEAK concentrations, with an increase in the number of atherosclerotic plaques after 24 months of follow-up, was observed in the studied population. Multivariable linear regression analysis showed that age, blood pressure, HDL-c, and sTWEAK concentrations were independent predictors of atherosclerotic burden after 24 months of follow-up. In addition, sTWEAK concentrations diminished in CKD patients in whom progressive silent atherosclerosis was observed. Multivariable linear regression analysis showed that age, sex, smoking status and sTWEAK levels were independent predictors of atheromatosis progression after 24 months of follow-up. CONCLUSIONS: Lower sTWEAK concentrations are associated with atherosclerotic burden and atheromatosis progression in CKD patients free of clinical CVD. These data suggest that sTWEAK could serve as a biomarker to predict CV risk before clinical manifestations.

Soluble TWEAK and Major Adverse Cardiovascular Events in Patients with CKD.

BACKGROUND AND OBJECTIVES: Soluble TNF-like weak inducer of apoptosis (sTWEAK) is a proinflammatory cytokine belonging to the TNF superfamily. sTWEAK concentrations have been associated with the presence of CKD and cardiovascular disease (CVD). We hypothesized that sTWEAK levels may relate to a higher prevalence of atherosclerotic plaques, vascular calcification, and cardiovascular outcomes observed in patients with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A 4-year prospective, multicenter, longitudinal study was conducted in 1058 patients with CKD stages 3-5D (mean age =58±13 years old; 665 men) but without any history of CVD from the NEFRONA Study (a study design on the prevalence of surrogate markers of CVD). Ankle-brachial index and B-mode ultrasound were performed to detect the presence of carotid and/or femoral atherosclerotic plaques together with biochemical measurements and sTWEAK assessment. Patients were followed for cardiovascular outcomes (follow-up of 3.13±1.15 years). RESULTS: Patients with more advanced CKD had lower sTWEAK levels. sTWEAK concentrations were independently and negatively associated with carotid intima-media thickness. sTWEAK levels were lower in patients with carotid atherosclerotic plaques but not in those with femoral plaques. After adjustment by confounders, the odds ratio (OR) for presenting carotid atherosclerotic plaques in patients in the lowest versus highest tertile of sTWEAK was 4.18 (95% confidence interval [95% CI], 2.89 to 6.08; P<0.001). Furthermore, sTWEAK levels were lower in patients with calcified carotid atherosclerotic plaques. The OR for presenting calcified carotid plaques was 1.77 (95% CI, 1.06 to 2.93; P=0.02) after multivariable adjustment. After the follow-up, 41 fatal and 68 nonfatal cardiovascular events occurred. In a Cox model, after controlling for potential confounding factors, patients in the lowest tertile of sTWEAK concentrations had a higher risk of fatal and nonfatal cardiovascular events (hazard ratio [HR], 2.40; 95% CI, 1.33 to 4.33; P=0.004) and cardiovascular mortality (HR, 2.67; 95% CI, 1.05 to 6.76; P=0.04). CONCLUSIONS: Low sTWEAK levels were associated with the presence of carotid atherosclerotic plaques in patients with CKD. Additionally, lower sTWEAK levels were associated with a higher risk of cardiovascular morbidity and mortality.

Predictors of Subclinical Atheromatosis Progression over 2 Years in Patients with Different Stages of CKD.

BACKGROUND AND OBJECTIVES: Ultrasonographic detection of subclinical atheromatosis is a noninvasive method predicting cardiovascular events. Risk factors predicting atheromatosis progression in CKD are unknown. Predictors of atheromatosis progression were evaluated in patients with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Our multicenter, prospective, observational study included 1553 patients with CKD (2009-2011). Carotid and femoral ultrasounds were performed at baseline and after 24 months. A subgroup of 476 patients with CKD was also randomized to undergo ultrasound examination at 12 months. Progression of atheromatosis was defined as an increase in the number of plaque territories analyzed by multivariate logistic regression. RESULTS: Prevalence of atheromatosis was 68.7% and progressed in 59.8% of patients after 24 months. CKD progression was associated with atheromatosis progression, suggesting a close association between pathologies. Variables significantly predicting atheromatosis progression, independent from CKD stages, were diabetes and two interactions of age with ferritin and plaque at baseline. Given that multiple interactions were found between CKD stage and age, phosphate, smoking, dyslipidemia, body mass index, systolic BP (SBP), carotid intima-media thickness, plaque at baseline, uric acid, cholesterol, 25-hydroxy vitamin D (25OH vitamin D), and antiplatelet and phosphate binders use, the analysis was stratified by CKD stages. In stage 3, two interactions (age with phosphate and plaque at baseline) were found, and smoking, diabetes, SBP, low levels of 25OH vitamin D, and no treatment with phosphate binders were positively associated with atheromatosis progression. In stages 4 and 5, three interactions (age with ferritin and plaque and plaque with smoking) were found, and SBP was positively associated with atheromatosis progression. In dialysis, an interaction between body mass index and 25OH vitamin D was found, and age, dyslipidemia, carotid intima-media thickness, low cholesterol, ferritin, and uric acid were positively associated with atheromatosis progression. CONCLUSIONS: Atheromatosis progression affects more than one half of patients with CKD, and predictive factors differ depending on CKD stage.

Diabetic nephropathy is an independent factor associated to severe subclinical atheromatous disease.

BACKGROUND: Atheromatous disease (AD) is a risk factor for death in renal patients. Traditional CV risk factors do not predict the presence of AD in this population. The aim of this study is to analyze whether the etiology of the primary renal disease influences in the risk of having silent AD. STUDY DESIGN: Observational cross-sectional study in chronic kidney disease patients without previous cardiovascular events. SETTINGS AND PARTICIPANTS: 2436 CKD subjects without any previous CV event included in the prospective Spanish multicenter NEFRONA study. Patients were classified according to primary renal disease: diabetic nephropathy (n = 347), vascular nephropathy (n = 476), systemic/glomerular disease (n = 447), tubulointerstitial and drug toxicity nephropathy (n = 320), polycystic kidney disease (n = 238), non-filiated nephropathy (n = 406) and other causes (n = 202). PREDICTORS: B-mode and Doppler ultrasonography analysis of the carotid arteries were performed to measure intima media thickness (IMT) and the presence of plaques. Clinical and laboratory parameters related to CV risk were also determined. OUTCOMES: AD was scored according with the ultrasonography findings and the ankle-brachial index into two large groups: absence or incipient AD and severe AD. RESULTS: In multivariate regression analysis, older age (OR 1.09/year [1.088-1.108]), smoking habit (OR 2.10 [1.61-2.74]), male gender (OR 1.33 [1.09-1.64]), grade-5D of CKD (OR 2.19 [1.74-2.74]), and diabetic nephropathy (OR 2.59 [1.93-3.48]) are independent risk factors for severe AD. The prevalence of silent AD was highest for diabetic nephropathy with grade-5D of CKD (82.2%) and lowest with stages 2-3 CKD systemic/glomerular disease (36.6%). LIMITATIONS: Observational study with the potential for confounding. CONCLUSION: In CKD patients without any CV event in the background clinical history, diabetic nephropathy as primary renal disease is the most significant factor associated to severe silent AD. Furthermore, this difference was independent of other conventional risk factors for atherosclerosis and CV events.

Paricalcitol Inhibits Aldosterone-Induced Proinflammatory Factors by Modulating Epidermal Growth Factor Receptor Pathway in Cultured Tubular Epithelial Cells.

Chronic kidney disease is characterized by Vitamin D deficiency and activation of the renin-angiotensin-aldosterone system. Increasing data show that vitamin D receptor agonists (VDRAs) exert beneficial effects in renal disease and possess anti-inflammatory properties, but the underlying mechanism remains unknown. Emerging evidence suggests that "a disintegrin and metalloproteinase" (ADAM)/epidermal growth factor receptor (EGFR) signalling axis contributes to renal damage. Aldosterone induces EGFR transactivation regulating several processes including cell proliferation and fibrosis. However, data on tubular epithelial cells is scarce. We have found that, in cultured tubular epithelial cells, aldosterone induced EGFR transactivation via TGF-α/ADAM17. Blockade of the TGF-α/ADAM17/EGFR pathway inhibited aldosterone-induced proinflammatory gene upregulation. Moreover, among the potential downstream mechanisms, we found that TGF-α/ADAM17/EGFR inhibition blocked ERK and STAT-1 activation in response to aldosterone. Next, we investigated the involvement of TGF-α/ADAM17/EGFR axis in VDRA anti-inflammatory effects. Preincubation with the VDRA paricalcitol inhibited aldosterone-induced EGFR transactivation, TGF-α/ADAM-17 gene upregulation, and downstream mechanisms, including proinflammatory factors overexpression. In conclusion, our data suggest that the anti-inflammatory actions of paricalcitol in tubular cells could depend on the inhibition of TGF-α/ADAM17/EGFR pathway in response to aldosterone, showing an important mechanism of VDRAs action.

Soluble TWEAK levels predict the presence of carotid atherosclerotic plaques in subjects free from clinical cardiovascular diseases.

OBJECTIVE: Reduced soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) levels have been related with cardiovascular disease. However, there are no data on the relationship between sTWEAK and atherosclerotic burden in subjects with or without cardiovascular risk factors but free from clinical disease. We have analyzed the association between circulating sTWEAK levels and the presence of carotid and/or femoral atherosclerotic plaques in subjects without known vascular disease. METHODS: A multicenter, cross-sectional study was conducted in 448 subjects free from clinical CVD. B-mode ultrasound was performed to detect the presence of carotid and/or femoral atherosclerotic plaques. sTWEAK concentrations were measured by enzyme-linked immunosorbent assay. RESULTS: sTWEAK serum levels were reduced in parallel with an increment in cardiovascular risk factors. sTWEAK concentrations were independently and negatively associated with carotid intima/media thickness. Subjects with atherosclerotic plaques showed a reduction in sTWEAK levels [808 (645-963) vs 993 (830-1278); p < 0.001]. A gradual decrease in sTWEAK levels was observed as the number of atherosclerotic plaques increased in our studied population. When we analyzed sTWEAK levels according to the vascular territory affected, we observed that sTWEAK concentrations were only diminished in subjects with carotid atherosclerotic plaques but not in those with femoral plaques. Following adjustment for various confounders, the OR for presenting carotid atherosclerotic plaque in subjects in lower vs higher tertile of sTWEAK levels was 8.09 [4.30-15.23; median (IQR); p < 0.001]. CONCLUSIONS: Diminished sTWEAK concentrations were significantly and independently associated with the presence of carotid atherosclerotic plaques in asymptomatic subjects.

A low fractional excretion of Phosphate/Fgf23 ratio is associated with severe abdominal Aortic calcification in stage 3 and 4 kidney disease patients.

BACKGROUND: Vascular calcification (VC) contributes to high mortality rates in chronic kidney disease (CKD). High serum phosphate and FGF23 levels and impaired phosphaturic response to FGF23 may affect VC. Therefore, their relative contribution to abdominal aortic calcification (AAC) was examined in patients CKD stages 3-4. METHODS: Potential risk factors for AAC, measured by the Kauppila Index (KI), were studied in 178 patients. RESULTS: In multivariate linear analysis, AAC associated positively with age, male gender, CKD-stage, presence of carotid plaques (CP) and also with FGF23, but negatively with fractional excretion of phosphate (FEP). Intriguingly, FEP increased with similar slopes with elevations in PTH, with reductions in GFR, and also with elevations in FGF23 but the latter only in patients with none (KI = 0) or mild (KI = 1-5) AAC. Lack of a FEP-FGF23 correlation in patients with severe AAC (KI > 5) suggested a role for an impaired phosphaturic response to FGF23 but not to PTH in AAC. Logistic and zero-inflated analysis confirmed the independent association of age, CKD stage, male gender and CP with AAC, and also identified a threshold FEP/FGF23 ratio of 1/3.9, below which the chances for a patient of presenting severe AAC increased by 3-fold. Accordingly, KI remained unchanged as FEP/FGF23 ratios decreased from 1/1 to 1/3.9 but markedly increased in parallel with further reductions in FEP/FGF23 < 1/3.9. CONCLUSIONS: In CKD 3-4, an impaired phosphaturic response to FGF23 with FEP/FGF23 < 1/3.9 associates with severe AAC independently of age, gender or CP.

Soluble TWEAK is associated with atherosclerotic burden in patients with chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is characterized by a high mortality rate, primarily due to cardiovascular disease. Reduced soluble TNF-like weak inducer of apoptosis (sTWEAK) levels have been related with endothelial function in CKD patients. However, there are no data on the relationship between sTWEAK and its scavenger receptor CD163 and atherosclerotic burden in CKD. METHODS: A cross-sectional, observational study was conducted in 58 patients with CKD stages 1-3, 86 with CKD stages 4-5, 195 on dialysis and 86 healthy controls. The severity of atherosclerosis was estimated with the atherosclerosis score (AS), combining the results of ankle-brachial index and carotid ultrasound. sTWEAK and CD163 plasma concentrations were measured by ELISA. RESULTS: sTWEAK plasma levels were diminished and CD163 concentrations were increased in patients with CKD compared with controls (sTWEAK: median [interquartile range] 308 pg/mL [258-378] vs. 371 pg/mL [319-455]; p<0.001; and CD163: 1,047 ng/mL [740-1,495] vs. 540 ng/mL [319-765]; p<0.001; respectively). A weak but statistically significant association between sTWEAK or CD163 and carotid intima-media thickness (r = -0.109, p = 0.025; r = 0.179, p<0.001; respectively) was observed. Patients with more severe atherosclerosis presented a higher reduction in sTWEAK concentrations (312 pg/mL [302-322] vs. 368 pg/mL [351-385]; p<0.001) and a higher increment in CD163 levels (1,182 ng/mL [1,107-1,258] vs. 826 ng/mL [733-919]; p<0.001). After multivariable analysis, only elevated sTWEAK levels were associated with reduced risk of atherosclerosis (0.34 [0.14-0.86], p = 0.02). CONCLUSIONS: A significant reduction in sTWEAK and increment in CD163 plasma levels were observed in patients with more severe atherosclerosis. Our results indicate that sTWEAK could be a novel biomarker of atherosclerotic burden in CKD patients.