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

Carotid plaque thickness predicts cardiovascular events and death in patients with chronic kidney disease

BACKGROUND

Classical risk scoring systems underestimate the risk of cardiovascular disease in chronic kidney disease (CKD). Coronary artery calcium score (CACS) has improved prediction of cardiovascular events in patients with CKD. The maximal carotid plaque thickness (cPTmax) measured in ultrasound scans of the carotid arteries has demonstrated similar predictive value as CACS in the general population. This is the first study to investigate whether cPTmax can predict cardiovascular events in CKD and to compare the predictive value of cPTmax and CACS in CKD.

METHOD

Two hundred patients with CKD stage 3 from the Copenhagen CKD Cohort underwent ultrasound scanning of the carotid arteries. The assessment consisted of locating plaque and measuring the thickest part of the plaque, cPTmax. Based on the distribution of cPTmax, the participants were divided into 3 groups: No plaques, cPTmax 1.0-1.9 mm and cPTmax > 1.9 mm (median cPTmax = 1.9 mm among patients with plaques). To measure CACS, 175 of the patients underwent a non-contrast CT scan of the coronary arteries. The follow-up time spanned between the ultrasound scan and a predefined end-date or the time of first event, defined as a composite of major cardiovascular events or death of any cause (MACE).

RESULTS

The median follow-up time was 5.4 years during which 45 patients (22.5%) developed MACE. In a Cox-regression adjusted for classical cardiovascular risk factors, patients with cPTmax > 1.9 mm had a significantly increased hazard ratio of MACE (HR 3.2, CI: 1.1-9.3), p = 0.031) compared to patients without plaques. C-statistics was used to evaluate models for predicting MACE. The improvement in C-statistics was similar for the two models including classical cardiovascular risk factors plus cPTmax (0.247, CI: 0.181-0.312) and CACS (0.243, CI: 0.172-0.315), respectively, when compared to a model only controlled for time since baseline (a Cox model with no covariates).

CONCLUSION

Our results indicate that cPTmax may be useful for predicting MACE in CKD. cPTmax and CACS showed similar ability to predict MACE.

Risk factors for progression in patients with KDOQI stage 3 Chronic Kidney Disease (PROGRESER study)

INTRODUCTION

The PROGRESER study is a multicentre, prospective, observational, 3-year follow-up study of a cohort of patients with stage 3 chronic kidney disease (CKD) from different nephrology departments of hospitals in the Spanish healthcare system. The primary study objective was to analyse risk factors for CKD progression, identifying possible differences between patients with and without diabetes mellitus (DM). The secondary objective was to analyse if the cardiovascular risk factors were also associated with CKD progression.

PATIENTS AND METHODS

A total of 462 patients (342 men and 120 women; mean age 66.5 ± 11.5 years) were recruited from 25 participating sites in Spain. Clinical, epidemilogical and analytical data were recorder in an electronic registrer each six months. Biological samples were obtained and frozen for a biobank record at baseline and at 18 and 36 months.

RESULTS

The initial mean glomerular filtration rate estimated by MDRD and after that reestimated by CKD-EPI was 43.9 ± 7.9 mL/min/1.73 m2; and 29 ± 6,8 mL/min/1,73 m2 at 3 years. 27.3% of patients had microalbuminuria and 22.5% had macroalbuminuria. Two-thirds of the patients (66.2%) presented renal damage progression according to the study criteria (decrease of more than 15% in eGFR over the baseline value). 38.7% presented a reduction in eGFR ≥ 30%; 20.3% had a reduction in eGFR ≥40%; 10.4% had a reduction ≥50% and 6.9% had a reduction ≥57%. Of the 199 diabetics, 134 (67.3%) suffered renal damage progression. Of the 263 non-diabetics, 172 (65.3%) presented progression (p = 0.456). 27.3% of patients had microalbuminuria and 22.5% proteinuria. The study found that CKD progression to a higher stage was not greater in diabetic compared to non-diabetic patients. Multivariate analysis revealed that the presence of arterial hypertension bordered on significance as a progression factor in non-diabetic patients (p = 0.07), and that, in diabetic patients, lower calcium levels and elevated intact parathyroid hormone levels at baseline were associated with progression.

CONCLUSION

in our study we have not found new factors for progression of renal damage, different from the yet well known traditional factors. DM "per se" was not a differential factor for progression in relation with non DM patients. Progression of renal damage in patients with CKD-3 KDOQI may be interpreted in a multifactorial context. The search for new biomarkers, different from traditional ones, is necessary to establish new therapeutic strategies to prevent the progression of CKD.

Pentoxifylline ameliorates subclinical atherosclerosis progression in patients with type 2 diabetes and chronic kidney disease: a randomized pilot trial

BACKGROUND

Diabetic kidney disease (DKD) is associated with a higher risk of cardiovascular disease (CVD). Pentoxifylline (PTF), a nonselective phosphodiesterase inhibitor with anti-inflammatory, antiproliferative, and antifibrotic actions, has demonstrated renal benefits in both clinical trials and meta-analyses. The present work aimed to study the effects of PTF on the progression of subclinical atherosclerosis (SA) in a population of patients with diabetes and moderate to severe chronic kidney disease (CKD).

METHODS

In this open-label, randomized controlled, prospective single-center pilot study the evolution of carotid intima-media thickness (CIMT) and ankle-brachial index (ABI) were determined in 102 patients with type 2 diabetes mellitus and CKD assigned to PTF, aspirin or control groups during 18 months. We also determined the variations in the levels of inflammatory markers and Klotho (KL), a protein involved in maintaining cardiovascular health, and their relationship with the progression of SA.

RESULTS

Patients treated with PTF presented a better evolution of CIMT, increased KL mRNA levels in peripheral blood cells (PBCs) and reduced the inflammatory state. The progression of CIMT values was inversely related to variations in KL both in serum and mRNA expression levels in PBCs. Multiple regression analysis demonstrated that PTF treatment and variations in mRNA KL expression in PBCs, together with changes in HDL, were significant determinants for the progression of CIMT (adjusted R2 = 0.24, P < 0.001) independently of traditional risk factors. Moreover, both variables constituted protective factors against a worst progression of CIMT [OR: 0.103 (P = 0.001) and 0.001 (P = 0.005), respectively].

CONCLUSIONS

PTF reduced SA progression assessed by CIMT variation, a beneficial effect related to KL gene expression in PBCs.

TRIAL REGISTRATION

The study protocol code is PTF-AA-TR-2009 and the trial was registered on the European Union Drug Regulating Authorities Clinical Trials (EudraCT #2009-016595-77). The validation date was 2010-03-09.

Blood Hemoglobin Concentrations and the Incidence of Lower Extremity Peripheral Arterial Disease in Patients Undergoing Hemodialysis: 10-Year Outcomes of the Q-Cohort Study

BACKGROUND

Lower extremity peripheral arterial disease is a potentially lethal cardiovascular complication in patients undergoing hemodialysis. Anemia is a risk factor for cardiovascular disease among the hemodialysis population. However, whether blood hemoglobin concentration is associated with the risk of peripheral arterial disease progression in this population remains undetermined.

METHODS AND RESULTS

This is an extension of a 4-year multicenter, prospective, observational cohort study to 10 years. A total of 3504 Japanese patients undergoing maintenance hemodialysis were recruited between 2006 and 2007. The primary exposure was blood hemoglobin concentration at baseline. The main outcome was the first-ever incidence of major adverse limb events (MALE), composed of endovascular treatment, bypass surgery, and amputation. Multivariable-adjusted Cox proportional hazards model, Fine-Gray subdistribution hazards model, restricted cubic spline analysis, and restricted mean survival time analysis were used to determine the association of blood hemoglobin concentration with the incidence of MALE. During a median follow-up of 8.0 years, 257 patients experienced MALE. A Cox proportional hazards model showed that the risk of MALE in patients with blood hemoglobin concentrations <10.0 g/dL was significantly higher than in patients with concentrations of 11.0 to 11.9 g/dL, even after adjusting for confounding factors. In contrast, elevated hemoglobin concentration (≥12.0 g/dL) was not significantly associated with increased risk of MALE. Similar associations were observed when the Fine-Gray subdistribution regression model was used by setting all-cause mortality as the competing risk.

CONCLUSIONS

A low blood hemoglobin concentration is an independent risk factor for peripheral arterial disease progression in patients undergoing maintenance hemodialysis.

B- and T-lymphocyte attenuator could be a new player in accelerated atherosclerosis associated with chronic kidney disease

BACKGROUND

In chronic kidney disease (CKD), cardiovascular morbi-mortality is higher than in general population. Atherosclerotic cardiovascular disease is accelerated in CKD, but specific CKD-related risk factors for atherosclerosis are unknown.

METHODS

CKD patients from the NEFRONA study were used. We performed mRNA array from blood of patients free from atheroma plaque at baseline, with (n=10) and without (n=10) de novo atherosclerotic plaque development 2 years later. Selected mRNA candidates were validated in a bigger sample (n=148). Validated candidates were investigated in vivo in an experimental model of CKD-accelerated atherosclerosis, and in vitro in murine macrophages.

RESULTS

mRNA array analysis showed 92 up-regulated and 67 down-regulated mRNAs in samples from CKD patients with de novo plaque development. The functional analysis pointed to a paramount role of the immune response. The validation in a bigger sample confirmed that B- and T-lymphocyte co-inhibitory molecule (BTLA) down-regulation was associated with de novo plaque presence after 2 years. However, BTLA down-regulation was not found to be associated with atherosclerotic progression in patients with plaque already present at baseline. In a model of CKD-accelerated atherosclerosis, mRNA and protein expression levels of BTLA were significantly decreased in blood samples and atheroma plaques. Plaques from animals with CKD were bigger, had more infiltration of inflammatory cells, higher expression of IL6 and IL17 and less presence of collagen than plaques from control animals. Incubation of macrophages with rat uremic serum decreased BTLA expression.

CONCLUSIONS

BTLA could be a potential biomarker or therapeutic target for atherosclerosis incidence in CKD patients.

Factors associated with carotid intima-media thickness progression in patients with asymptomatic hyperuricemia: insights from the PRIZE study

Hyperuricemia is reportedly associated with the progression of carotid intima-media thickness (IMT), a surrogate of cardiovascular risks and events. However, factors associated with carotid IMT progression in patients with asymptomatic hyperuricemia are largely unknown. In this post-hoc analysis of the multicenter, randomized PRIZE study, we analyzed data from a total of 326 patients who underwent carotid ultrasonography in a blind manner at baseline and 24 months to evaluate carotid IMT. Mean and maximum IMT at the common carotid artery (CCA) were measured at a central core laboratory. Factors related to the absolute change in mean and maximum IMT from baseline to 24 months were explored. Overall, the adjusted mean [0.0032 (- 0.0214 to 0.0278) mm] and maximum [0.0011 (- 0.0327 to 0.0351) mm] CCA-IMT increased numerically from baseline to 24 months. Multivariable analysis identified higher body mass index, history of atherosclerotic cardiovascular disease (ASCVD), and lower mean CCA-IMT at baseline as significant factors associated with the increase in mean CCA-IMT. In addition, older age and lower mean CCA-IMT at baseline were significant factors for an increased absolute change in the maximum CCA-IMT at 24 months. The present sub-analysis of the PRIZE study showed higher body mass index, history of ASCVD, and older age as significant factors associated with CCA-IMT progression in patients with asymptomatic hyperuricemia. These factors may be considered when identifying the possible risk of atherosclerotic progression in this specific patient population of hyperuricemia.Trial registration: UMIN000012911 and UMIN000041322.

Association of Intima-Media Thickness Measured at the Common Carotid Artery With Incident Carotid Plaque: Individual Participant Data Meta-Analysis of 20 Prospective Studies

Background The association between common carotid artery intima-media thickness (CCA-IMT) and incident carotid plaque has not been characterized fully. We therefore aimed to precisely quantify the relationship between CCA-IMT and carotid plaque development. Methods and Results We undertook an individual participant data meta-analysis of 20 prospective studies from the Proof-ATHERO (Prospective Studies of Atherosclerosis) consortium that recorded baseline CCA-IMT and incident carotid plaque involving 21 494 individuals without a history of cardiovascular disease and without preexisting carotid plaque at baseline. Mean baseline age was 56 years (SD, 9 years), 55% were women, and mean baseline CCA-IMT was 0.71 mm (SD, 0.17 mm). Over a median follow-up of 5.9 years (5th-95th percentile, 1.9-19.0 years), 8278 individuals developed first-ever carotid plaque. We combined study-specific odds ratios (ORs) for incident carotid plaque using random-effects meta-analysis. Baseline CCA-IMT was approximately log-linearly associated with the odds of developing carotid plaque. The age-, sex-, and trial arm-adjusted OR for carotid plaque per SD higher baseline CCA-IMT was 1.40 (95% CI, 1.31-1.50; I²=63.9%). The corresponding OR that was further adjusted for ethnicity, smoking, diabetes, body mass index, systolic blood pressure, low- and high-density lipoprotein cholesterol, and lipid-lowering and antihypertensive medication was 1.34 (95% CI, 1.24-1.45; I²=59.4%; 14 studies; 16 297 participants; 6381 incident plaques). We observed no significant effect modification across clinically relevant subgroups. Sensitivity analysis restricted to studies defining plaque as focal thickening yielded a comparable OR (1.38 [95% CI, 1.29-1.47]; I²=57.1%; 14 studies; 17 352 participants; 6991 incident plaques). Conclusions Our large-scale individual participant data meta-analysis demonstrated that CCA-IMT is associated with the long-term risk of developing first-ever carotid plaque, independent of traditional cardiovascular risk factors.

Endothelial Cell Dysfunction and Increased Cardiovascular Risk in Patients With Chronic Kidney Disease

The endothelium is considered to be the gatekeeper of the vessel wall, maintaining and regulating vascular integrity. In patients with chronic kidney disease, protective endothelial cell functions are impaired due to the proinflammatory, prothrombotic and uremic environment caused by the decline in kidney function, adding to the increase in cardiovascular complications in this vulnerable patient population. In this review, we discuss endothelial cell functioning in healthy conditions and the contribution of endothelial cell dysfunction to cardiovascular disease. Further, we summarize the phenotypic changes of the endothelium in chronic kidney disease patients and the relation of endothelial cell dysfunction to cardiovascular risk in chronic kidney disease. We also review the mechanisms that underlie endothelial changes in chronic kidney disease and consider potential pharmacological interventions that can ameliorate endothelial health.

Clinical Factors Associated with Arterial Stiffness in Chronic Kidney Disease

BACKGROUND

Arterial stiffness influences the prognosis of patients with end-stage kidney disease; however, the factors that promote arterial stiffness in chronic kidney disease (CKD) patients remain unknown. We aimed to explore the clinical factors associated with arterial stiffness in CKD.

METHODS

Between September 2017 and September 2022, all CKD patients treated at the Department of Nephrology, General Hospital of the Chinese People's Liberation Army, excluding dialysis patients, were screened and their medical records within the last month were collected. Arterial stiffness was measured by the augmentation index (AIx). The correlative clinical factors with arterial stiffness were explored in different linear regression models.

RESULTS

559 patients were included in the study. AIx@75 increased as the deterioration of CKDG1-CKDG5, with values of 1 (-9, 11), 5.5 (-4, 13.25), 9 (0, 16), 12 (1.5, 23.5), and 22 (13, 28), respectively (Z = 63.03, p < 0.001). Multivariate linear regression analysis showed that AIx@75 was positively associated with female sex (β = 8.926, 95% confidence interval (CI) 6.291, 11.562, p < 0.001), age (β = 0. 485, 95% CI 0.39, 0.58, p < 0.001), mean arterial pressure (MAP) (β = 0.255, 95% CI 0.159, 0.35, p < 0.001), and was negatively associated with ACEI/ARB (β = -4.466, 95% CI -6.963, -1.969, p < 0.001) and glucocorticoid (β = -3.163, 95% CI -6.143, -0.183, p = 0.038). Smoking, eGFR, hemoglobin, and cause of disease were associated with AIx@75 in multivariate linear regression models when considering factors partly.

CONCLUSIONS

Female, age, smoking, MAP, eGFR, cause of disease, ACEI/ARB, and glucocorticoid were found to be associated with atherosclerosis in CKD patients.

Lipid profile of patients treated with evolocumab in Spanish hospital nephrology units (RETOSS NEFRO)

BACKGROUND AND OBJECTIVE

To describe the clinical characteristics, the reasons for initiating therapy and the effects of treatment in the initial phase of evolocumab availability in the Nephrology Units of Spain.

MATERIAL AND METHODS

Retrospective, observational and multicentric study that included patients initiating treatment with evolocumab (from February 2016 to August 2018), in 15 Nephrology Units in Spain. The demographic and clinical characteristics of the patients, the lipid lowering treatment and the evolution of the lipid profiles between 24 weeks pre-initiation and 12±4 weeks post-initiation of evolocumab were reviewed.

RESULTS

60 patients were enrolled: 53.3% women; mean (SD) age, 56.9 (12.8) years, 45.0% with familial hypercholesterolemia (FH) (5.0% homozygous and 40.0% heterozygous) and 65.0% with atherosclerotic cardiovascular disease. The mean (SD) eGFR was 62.6 (30.0) ml/min/1.73m² (51.7% of patients had eGFR <60ml/min/1.73m² [CKD stage>2]), 50.0% had proteinuria (>300mg/g) and 10.0% had nephrotic syndrome. Other CV risk factors were hypertension (75.0%), diabetes (25.0%), and smoking (21.7%). A 40.0% of patients were statin intolerant. At evolocumab initiation, 41.7% of patients were on a high intensity statin, 18.3% on moderate intensity statin and 50.0% were receiving ezetimibe. Mean (SD) LDL-c at evolocumab initiation was 179.7 (62.9) mg/dL (53.4% of patients with LDL-c ≥160mg/dL and 29.3% ≥190mg/dL). After 12 weeks, evolocumab resulted in LDL-c reductions of 60.1%. At week 12, 90.0% of patients reached LDL-c levels <100mg/dL, 70.0% <70mg/dL, and 55.0% <55mg/dL, while mean eGFR levels and statin use remained stable.

CONCLUSION

In Nephrology Units of Spain, evolocumab was predominantly prescribed in patients with FH, chronic renal disease (CRD>2) and secondary prevention, with LDL-c levels above those recommended by the guidelines. Evolocumab used in clinical practice significantly reduced the LDL-c levels in all patients included in the study.

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.

Predictive Model for High Coronary Artery Calcium Score in Young Patients with Non-Dialysis Chronic Kidney Disease

Cardiovascular disease is a major complication of chronic kidney disease. The coronary artery calcium (CAC) score is a surrogate marker for the risk of coronary artery disease. The purpose of this study is to predict outcomes for non-dialysis chronic kidney disease patients under the age of 60 with high CAC scores using machine learning techniques. We developed the predictive models with a chronic kidney disease representative cohort, the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD). We divided the cohort into a training dataset (70%) and a validation dataset (30%). The test dataset incorporated an external dataset of patients that were not included in the KNOW-CKD cohort. Support vector machine, random forest, XGboost, logistic regression, and multi-perceptron neural network models were used in the predictive models. We evaluated the model’s performance using the area under the receiver operating characteristic (AUROC) curve. Shapley additive explanation values were applied to select the important features. The random forest model showed the best predictive performance (AUROC 0.87) and there was a statistically significant difference between the traditional logistic regression model and the test dataset. This study will help identify patients at high risk of cardiovascular complications in young chronic kidney disease and establish individualized treatment strategies.

Carotid plaque thickness is increased in chronic kidney disease and associated with carotid and coronary calcification

BACKGROUND

Chronic kidney disease accelerates both atherosclerosis and arterial calcification. The aim of the present study was to explore whether maximal carotid plaque thickness (cPTmax) was increased in patients with chronic kidney disease compared to controls and associated with cardiovascular disease and severity of calcification in the carotid and coronary arteries.

METHODS

The study group consisted of 200 patients with chronic kidney disease stage 3 from the Copenhagen Chronic Kidney Disease Cohort and 121 age- and sex-matched controls. cPTmax was assessed by ultrasound and arterial calcification by computed tomography scanning.

RESULTS

Carotid plaques were present in 58% of patients (n = 115) compared with 40% of controls (n = 48), p = 0.002. Among participants with plaques, cPTmax (median, interquartile range) was significantly higher in patients compared with controls (1.9 (1.4-2.3) versus 1.5 (1.2-1.8) mm), p = 0.001. Cardiovascular disease was present in 9% of patients without plaques (n = 85), 23% of patients with cPTmax 1.0-1.9 mm (n = 69) and 35% of patients with cPTmax >1.9 mm (n = 46), p = 0.001. Carotid and coronary calcium scores >400 were present in 0% and 4%, respectively, of patients with no carotid plaques, in 19% and 24% of patients with cPTmax 1.0-1.9 mm, and in 48% and 53% of patients with cPTmax >1.9 mm, p<0.001.

CONCLUSIONS

This is the first study showing that cPTmax is increased in patients with chronic kidney disease stage 3 compared to controls and closely associated with prevalent cardiovascular disease and severity of calcification in both the carotid and coronary arteries.

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.

Lipid profile of patients treated with evolocumab in Spanish hospital nephrology units (RETOSS NEFRO)

BACKGROUND AND OBJECTIVE

To describe the clinical characteristics, the reasons for initiating therapy and the effects of treatment in the initial phase of evolocumab availability in the Nephrology Units of Spain.

MATERIAL AND METHODS

Retrospective, observational and multicentric study that included patients initiating treatment with evolocumab (from February 2016 to August 2018), in 15 Nephrology Units in Spain. The demographic and clinical characteristics of the patients, the lipid lowering treatment and the evolution of the lipid profiles between 24 weeks pre-initiation and 12±4 weeks post-initiation of evolocumab were reviewed.

RESULTS

Sixty patients were enrolled: 53.3% women; mean (SD) age, 56.9 (12.8) years, 45.0% with familial hypercholesterolemia (FH) (5.0% homozygous and 40.0% heterozygous) and 65.0% with atherosclerotic cardiovascular (CV) disease. The mean (SD) eGFR was 62.6 (30.0)ml/min/1.73m2 (51.7% of patients had eGFR<60ml/min/1.73m2 [CKD stage>2]), 50.0% had proteinuria (>300mg/g) and 10.0% had nephrotic syndrome. Other CV risk factors were hypertension (75.0%), diabetes (25.0%), and smoking (21.7%). A 40.0% of patients were statin intolerant. At evolocumab initiation, 41.7% of patients were on a high-intensity statin, 18.3% on moderate intensity statin and 50.0% were receiving ezetimibe. Mean (SD) LDL-c at evolocumab initiation was 179.7 (62.9)mg/dL (53.4% of patients with LDL-c≥160mg/dL and 29.3%≥190mg/dL). After 12 weeks, evolocumab resulted in LDL-c reductions of 60.1%. At week 12, 90.0% of patients reached LDL-c levels <100mg/dL, 70.0% <70mg/dL, and 55.0% <55mg/dL, while mean eGFR levels and statin use were remained stable.

CONCLUSION

In Nephrology Units of Spain, evolocumab was predominantly prescribed in patients with FH, chronic renal disease (CRD>2) and secondary prevention, with LDL-c levels above those recommended by the guidelines. Evolocumab used in clinical practice significantly reduced the LDL-c levels in all patients included in the study.

Klotho as a biomarker of subclinical atherosclerosis in patients with moderate to severe chronic kidney disease

Chronic kidney disease (CKD) has been associated with a higher risk of cardiovascular disease (CVD). CKD patients present a decrease in the levels of the protein Klotho that accompanies the decrease in kidney function. This protein has been related to protective effects against CVD. However, it is unclear whether circulating Klotho, and its expression in peripheral blood cells (PBCs) are also associated with subclinical atherosclerosis in CKD. The present study aimed to study the relationship between Klotho and subclinical atherosclerosis in a population of patients with moderate to severe CKD. We determined the serum levels and gene expression in PBCs levels of Klotho and three inflammatory cytokines in 103 patients with CKD and investigated their relationship with two surrogate markers of subclinical atherosclerotis: ankle-brachial index (ABI) and carotid intima-media thickness (CIMT). Patients with subclinical atherosclerosis presented lower serum and PBCs expression levels of Klotho. Both variables were associated with the presence of subclinical atherosclerosis, being directly related with ABI and inversely with CIMT (P < 0.0001 for both). Multiple regression analysis demonstrated that both variables were significant determinants for ABI (adjusted R2 = 0.511, P < 0.0001) and CIMT (adjusted R2 = 0.445, P < 0.0001), independently of traditional and emergent cardiovascular risk factors. Moreover, both constituted protective factors against subclinical atherosclerosis [OR: 0.993 (P = 0.002) and 0.231 (P = 0.025), respectively]. Receiver operating characteristic analysis pointed to the utility of serum Klotho (area under the curve [AUC]: 0.817, 95% CI: 0.736-0.898, P < 0.001) and its gene expression in PBCs (AUC: 0.742, 95% CI: 0.647-0.836, P < 0.001) to distinguish subclinical atherosclerosis. The reductions in serum and PBCs expression levels of Klotho in CKD patients are independently associated with the presence of for subclinical atherosclerosis. Further research exploring whether therapeutic approaches to maintain or elevate Klotho could reduce the impact of CVD in CKD patients is warranted.

Association between chronic kidney disease and new-onset dyslipidemia: The Japan Specific Health Checkups (J-SHC) study

BACKGROUND AND AIMS

Dyslipidemias are common among patients with chronic kidney disease (CKD) and are a major risk factor for cardiovascular disease. This study aimed to investigate the association between early-stage CKD and new-onset dyslipidemia for each lipid profile.

METHODS

This nationwide longitudinal study included data from the Japan Specific Health Checkups (J-SHC) Study. New-onset dyslipidemia was indicated by hypertriglyceridemia (High-TG; ≥150 mg/dL), hyper-LDL cholesterolemia (High-LDL-C; ≥140 mg/dL), or hypo-HDL chelesterolemia (Low-HDL-C; <40 mg/dL) levels according to the guideline of Japan Atherosclerosis Society, or High-TG/HDL-C ratio (≥3.5) which was a good predictor of atherosclerosis. The incidence of new-onset dyslipidemia was compared between participants with and without CKD. Survival curves were used to analyze the incidence of each dyslipidemia.

RESULTS

Of 289,462 participants with a median follow-up period of 3 years, the incidence of High-TG, High-LDL-C, Low-HDL-C, and High-TG/HDL-C ratios were 64.4/1000 person-years, 83.1/1000 person-years, 14.5/1000 person-years, and 39.6/1000 person-years, respectively. The adjusted hazard ratios (95% confidence intervals) for High-TG, High-LDL-C, Low-HDL-C, and High-TG/HDL-C ratio were 1.09 (1.05-1.13), 0.99 (0.95-1.04), 1.12 (1.05-1.18), and 1.14 (1.09-1.18), respectively, in CKD participants as compared to non-CKD participants. Decreased eGFR and presence of proteinuria were independently associated with higher risks for new-onset of High-TG, Low-HDL-C, and High-TG/HDL-C ratios.

CONCLUSIONS

CKD was associated with a higher risk of new-onset High-TG, Low-HDL-C, and High-TG/HDL-C ratios, but not High-LDL-C, in the general population. These CKD-specific lipid abnormalities may explain the residual risk for CKD-related cardiovascular disease.

A Nomogram for Identifying Subclinical Atherosclerosis in Chronic Kidney Disease

Purpose

Atherosclerosis contributes substantially to cardiovascular mortality in patients with chronic kidney disease (CKD). But precise risk model for subclinical atherosclerosis in the CKD population is still lacking. The study aimed to develop and validate a nomogram for screening subclinical atherosclerosis among CKD patients without dialysis.

Patients and Methods

A total of 1452 CKD stage 1‒5 has been recruited in this cross-sectional study. Subclinical atherosclerosis was diagnosed with carotid ultrasonography. Patients were divided into the training set and validation set. The risk factors of atherosclerosis were identified by the training set and confirmed by the validation set. The receiver operating characteristic (ROC) curves and decision curve analyses (DCA) were executed to evaluate the accuracy of fitted logistic models in training and validation sets. Finally, a nomogram based on constructed logistic regression model in all participants was plotted.

Results

A total of 669 (46.1%) patients were diagnosed with subclinical carotid atherosclerosis. Binary logistic regression analysis showed that males, age, hypertension, diabetes, CKD stages, calcium, platelet, and albumin were risk factors for atherosclerosis. The accuracy of fitted logistic models was evaluated by the area under the ROC curve (AUC), which showed good predictive accuracy in the training set (AUC=0.764 (95% Confidence interval (CI): 0.733–0.794) and validation set (AUC=0.808 (95% CI: 0.765–0.852). A high net benefit was also proven by the DCA. Finally, these predictors were all included to generate the nomogram.

Conclusion

This proposed nomogram shows excellent predictive ability and might have a significant clinical implication for detecting subclinical atherosclerosis in patients with CKD.

Independent effects of secondary hyperparathyroidism and hyperphosphatemia on chronic kidney disease progression and cardiovascular events: an analysis from the NEFRONA cohort

BACKGROUND

Secondary hyperparathyroidism (SHPT) is a complication of chronic kidney disease (CKD), and it is associated with changes in calcium and phosphate. These related changes have been associated with increased cardiovascular mortality and CKD progression. It is not clear whether negative outcomes linked to SHPT are confounded by such factors. The present study was designed to assess the possible independent effects of SHPT (defined as patients with excessive PTH levels or on treatment with PTH reducing agents) on the risk of CKD progression and CVE incidence in CKD patients, as well as whether hypercalcemia and/or hyperphosphatemia act as effect modifiers.

METHODS

The study enrolled 2445 CKD patients without previous CVE from the NEFRONA cohort (950 stage 3, 612 stage 4, 195 stage 5 and 688 on Dialysis). Multivariate logistic and Fine and Gray regression analysis were used to determine the risk of patients of suffering CKD progression or a CVE.

RESULTS

Prevalence of SHPT in the whole cohort was 65.6% (CKD 3 54.7%; CKD 4 74.7%; CKD 5 71.4%; Dialysis 68.6%). After 2-years, 301 patients presented CKD progression. During 4-years follow-up, 203 CVE were registered. Patients with SHPT showed a higher adjusted risk for CKD progression and CVE. Furthermore, hyperphosphatemia was shown to be an independent risk factor in both outcomes and did not modify SHPT effect. No significant interactions were detected between the presence of SHPT and hypercalcemia or hyperphosphatemia.

CONCLUSIONS

We conclude that SHPT and hyperphosphatemia are independently associated with CKD progression and the incidence of CVE in CKD patients.

Effects of chronic kidney disease and declining renal function on coronary atherosclerotic plaque progression: a PARADIGM substudy

AIMS 

To investigate the change in atherosclerotic plaque volume in patients with chronic kidney disease (CKD) and declining renal function, using coronary computed tomography angiography (CCTA).

METHODS AND RESULTS

In total, 891 participants with analysable serial CCTA and available glomerular filtration rate (GFR, derived using Cockcroft-Gault formulae) at baseline (CCTA 1) and follow-up (CCTA 2) were included. CKD was defined as GFR <60 mL/min/1.73 m2. Declining renal function was defined as ≥10% drop in GFR from the baseline. Quantitative assessment of plaque volume and composition were performed on both scans. There were 203 participants with CKD and 688 without CKD. CKD was associated with higher baseline total plaque volume, but similar plaque progression, measured by crude (57.5 ± 3.4 vs. 65.9 ± 7.7 mm3/year, P = 0.28) or annualized (17.3 ± 1.0 vs. 19.9 ± 2.0 mm3/year, P = 0.25) change in total plaque volume. There were 709 participants with stable GFR and 182 with declining GFR. Declining renal function was independently associated with plaque progression, with higher crude (54.1 ± 3.2 vs. 80.2 ± 9.0 mm3/year, P < 0.01) or annualized (16.4 ± 0.9 vs. 23.9 ± 2.6 mm3/year, P < 0.01) increase in total plaque volume. In CKD, plaque progression was driven by calcified plaques whereas in patients with declining renal function, it was driven by non-calcified plaques.

CONCLUSION

Decline in renal function was associated with more rapid plaque progression, whereas the presence of CKD was not.

Chronic kidney disease, atherosclerotic plaque characteristics on carotid magnetic resonance imaging, and cardiovascular outcomes

Background

It is unclear whether faster progression of atherosclerosis explains the higher risk of cardiovascular events in CKD. The objectives of this study were to 1. Characterize the associations of CKD with presence and morphology of atherosclerotic plaques on carotid magnetic resonance imaging (MRI) and 2. Examine the associations of baseline CKD and carotid atherosclerotic plaques with subsequent cardiovascular events.

Methods

In a subgroup (N = 465) of Systolic Blood Pressure Intervention Trial.

(SPRINT) participants, we measured carotid plaque presence and morphology at baseline and after 30-months with MRI. We examined the associations of CKD (baseline eGFR < 60 ml/min/1.73m²) with progression of carotid plaques and the SPRINT cardiovascular endpoint.

Results

One hundred and ninety six (42%) participants had CKD. Baseline eGFR in the non-CKD and CKD subgroups were 77 ± 14 and 49 ± 8 ml/min/1.73 m², respectively. Lipid rich necrotic-core plaque was present in 137 (29.5%) participants. In 323 participants with both baseline and follow-up MRI measurements of maximum wall thickness, CKD was not associated with progression of maximum wall thickness (OR 0.62, 95% CI 0.36 to 1.07, p = 0.082). In 96 participants with necrotic core plaque at baseline and with a valid follow-up MRI, CKD was associated with lower odds of progression of necrotic core plaque (OR 0.41, 95% CI 0.17 to 0.95, p = 0.039). There were 28 cardiovascular events over 1764 person-years of follow-up. In separate Cox models, necrotic core plaque (HR 2.59, 95% CI 1.15 to 5.85) but not plaque defined by maximum wall thickness or presence of a plaque component (HR 1.79, 95% CI 0.73 to 4.43) was associated with cardiovascular events. Independent of necrotic core plaque, CKD (HR 3.35, 95% CI 1.40 to 7.99) was associated with cardiovascular events.

Conclusions

Presence of necrotic core in carotid plaque rather than the presence of plaque per se was associated with increased risk of cardiovascular events. We did not find CKD to be associated with faster progression of necrotic core plaques, although both were independently associated with cardiovascular events. Thus, CKD may contribute to cardiovascular disease principally via mechanisms other than atherosclerosis such as arterial media calcification or stiffening.

Trial Registration

NCT01475747, registered on November 21, 2011.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02260-x.

Association of a single nucleotide polymorphism combination pattern of the Klotho gene with non-cardiovascular death in patients with chronic kidney disease

Background

Chronic kidney disease (CKD) is associated with an elevated risk of all-cause mortality, with cardiovascular death being extensively investigated. However, non-cardiovascular mortality represents the biggest percentage, showing an evident increase in recent years. Klotho is a gene highly expressed in the kidney, with a clear influence on lifespan. Low levels of Klotho have been linked to CKD progression and adverse outcomes. Single nucleotide polymorphisms (SNPs) of the Klotho gene have been associated with several diseases, but studies investigating the association of Klotho SNPs with non-cardiovascular death in CKD populations are lacking.

Methods

The main aim of this study was to assess whether 11 Klotho SNPs were associated with non-cardiovascular death in a subpopulation of the National Observatory of Atherosclerosis in Nephrology (NEFRONA) study (n = 2185 CKD patients).

Results

After 48 months of follow-up, 62 cardiovascular deaths and 108 non-cardiovascular deaths were recorded. We identified a high non-cardiovascular death risk combination of SNPs corresponding to individuals carrying the most frequent allele (G) at rs562020, the rare allele (C) at rs2283368 and homozygotes for the rare allele (G) at rs2320762 (rs562020 GG/AG + rs2283368 CC/CT + rs2320762 GG). Among the patients with the three SNPs genotyped (n = 1016), 75 (7.4%) showed this combination. Furthermore, 95 (9.3%) patients showed a low-risk combination carrying all the opposite genotypes (rs562020 AA + rs2283368 TT + rs2320762 GT/TT). All the other combinations [n = 846 (83.3%)] were considered as normal risk. Using competing risk regression analysis, we confirmed that the proposed combinations are independently associated with a higher {hazard ratio [HR] 3.28 [confidence interval (CI) 1.51–7.12]} and lower [HR 6 × 10⁻⁶ (95% CI 3.3 × 10⁻⁷–1.1 × 10⁻⁵)] risk of suffering a non-cardiovascular death in the CKD population of the NEFRONA cohort compared with patients with the normal-risk combination.

Conclusions

Determination of three SNPs of the Klotho gene could help in the prediction of non-cardiovascular death in CKD.

Cardiovascular Risk Assessment Using Ultrasonographic Surrogate Markers of Atherosclerosis and Arterial Stiffness in Patients With Chronic Renal Impairment: A Narrative Review of the Evidence and a Critical View of Their Utility in Clinical Practice

PURPOSE OF THE REVIEW

Validated tools to improve cardiovascular disease (CVD) risk assessment and mortality in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) are lacking. Noninvasive measures of arteriosclerosis and subclinical atherosclerosis such as pulse wave velocity (PWV) and carotid intima-media thickness (cIMT), respectively, have emerged as promising risk stratification tools and potential modifiable biomarkers. Their wide use as surrogate markers in clinical research studies is based on the strong pathophysiological links with CVD. However, whether their effect as risk stratification or intervention targets is superior to established clinical approaches is uncertain. In this review, we examine the evidence on the utility of PWV, cIMT, and plaque assessment in routine practice and highlight unanswered questions from the clinician's perspective.

SOURCES OF INFORMATION

Electronic databases PubMed and Google Scholar were searched until February 2020.

METHODS

This narrative review is based on peer-reviewed meta-analyses, national and international societies' guidelines, and on focused critical review of recent original studies and landmark studies in the field.

KEY FINDINGS

Although patients with CKD are considered in the high-risk CVD groups, there is still need for tools to improve risk stratification and individualized management strategies within this group of patients. Carotid intima-media thickness is associated with all-cause mortality, CVD mortality, and events in CKD and hemodialysis cohorts. However, the evidence that measurement of cIMT has a clinically meaningful role over and above existing risk scores and management strategies is limited. Plaque assessment is a better predictor than cIMT in non-CKD populations and it has been incorporated in recent nonrenal-specific guidelines. In the CKD population, one large observational study provided evidence for a potential role of plaque assessment in CKD similar to the non-CKD studies; however, whether it improves prediction and outcomes in CKD is largely understudied. Pulse wave velocity as a marker of arterial stiffness has a strong pathophysiological link with CVD in CKD and numerous observational studies demonstrated associations with increased cardiovascular risk. However, PWV did not improve CVD reclassification of dialysis patients when added to common risk factors in a reanalysis of ESRD cohorts with available PWV data. Therapeutic strategies to regress PWV, independently from blood pressure reduction, have not been studied in well-conducted randomized trials.

LIMITATIONS

This study provides a comprehensive review based on extensive literature search and critical appraisal of included studies. Nevertheless, formal systematic literature review and quality assessment were not performed and the possibility of selection bias cannot be excluded.

IMPLICATIONS

Larger, prospective, randomized studies with homogeneous approach, designed to answer specific clinical questions and taking into consideration special characteristics of CKD and dialysis, are needed to study the potentially beneficial role of cIMT/plaque assessment and PWV in routine practice.

Magnesium Levels Modify the Effect of Lipid Parameters on Carotid Intima Media Thickness

Classical risk factors of atherosclerosis in the general population show paradoxical effects in chronic kidney disease (CKD) patients. Thus, low low-density lipoprotein (LDL) cholesterol levels have been associated with worse cardiovascular outcomes. Magnesium (Mg) is a divalent cation whose homeostasis is altered in CKD. Furthermore, Mg levels have been associated with cardiovascular health. The present study aims to understand the relationships of Mg and lipid parameters with atherosclerosis in CKD. In this analysis, 1754 participants from the Observatorio Nacional de Atherosclerosis en Nefrologia (NEFRONA) cohort were included. Carotid intima media thickness (cIMT) was determined in six arterial territories, and associated factors were investigated by linear regression. cIMT correlated positively with being male, Caucasian, a smoker, diabetic, hypertensive, dyslipidemic and with increased age, BMI, and triglyceride levels, and negatively with levels of HDL cholesterol. First-order interactions in linear regression analysis showed that Mg was an effect modifier on the influence of lipidic parameters. Thus, cIMT predicted values were higher when triglycerides or LDL levels were high and Mg levels were low. On the contrary, when Mg levels were high, this effect disappeared. In conclusion, Mg acts as an effect modifier between lipidic parameters and atherosclerotic cardiovascular disease. Therefore, Mg levels, together with lipidic parameters, should be taken into account when assessing atherosclerotic risk.

The Effect of Vitamin Supplementation on Subclinical Atherosclerosis in Patients without Manifest Cardiovascular Diseases: Never-ending Hope or Underestimated Effect?

Micronutrients, especially vitamins, play an important role in the evolution of cardiovascular diseases (CVD). It has been speculated that additional intake of vitamins may reduce the CVD burden by acting on the inflammatory and oxidative response starting from early stages of atherosclerosis, when the vascular impairment might still be reversible or, at least, slowed down. The current review assesses the role of major vitamins on subclinical atherosclerosis process and the potential clinical implications in patients without CVD. We have comprehensively examined the literature data for the major vitamins: A, B group, C, D, and E, respectively. Most data are based on vitamin E, D and C supplementation, while vitamins A and B have been scarcely examined for the subclinical atherosclerosis action. Though the fundamental premise was optimistic, the up-to-date trials with vitamin supplementation revealed divergent results on subclinical atherosclerosis improvement, both in healthy subjects and patients with CVD, while the long-term effect seems minimal. Thus, there are no conclusive data on the prevention and progression of atherosclerosis based on vitamin supplementation. However, given their enormous potential, future trials are certainly needed for a more tailored CVD prevention focusing on early stages as subclinical atherosclerosis.

Carotid intima-media thickness predicts carotid plaque development: Meta-analysis of seven studies involving 9341 participants

BACKGROUND

Carotid intima-media thickness and carotid plaque are well-established imaging markers used to capture different stages of the atherosclerotic disease process. We aimed to quantify to which extent carotid intima-media thickness predicts incidence of first-ever carotid plaque.

MATERIALS AND METHODS

Two independent reviewers conducted a comprehensive literature search of PubMed and Web of Science. To be eligible for inclusion, prospective studies were required to involve participants free of carotid plaque at baseline and report on the association of baseline carotid intima-media thickness with development of first-ever carotid plaque. Study-specific relative risks and 95% confidence intervals were collected and pooled using random-effects meta-analysis.

RESULTS

We identified seven relevant prospective studies involving a total of 9341 participants. Individuals were recruited between 1987 and 2012, average age at baseline was 54 years, and 63% were female. Studies reported on 1288 incident first-ever carotid plaques, occurring over an average maximum follow-up of 8.7 years. When individuals in the top fourth of baseline carotid intima-media thickness distribution were compared with those in the bottom fourth, the pooled relative risk for incidence of first-ever carotid plaque was 1.78 (95% confidence interval: 1.53-2.07, P < .001, I²  = 2.8%). The strength of association was not modified by mean baseline age, proportion of female participants, length of follow-up, year of baseline, and geographical location of the studies.

CONCLUSIONS

In general population studies, elevated baseline carotid intima-media thickness is associated with incidence of carotid plaque in individuals free of carotid plaque at baseline.

Mechanisms of Vascular Calcification in Kidney Disease

The increase in prevalence and severity of vascular calcification in chronic kidney disease is a result of complex interactions between changes in the vascular bed, mineral metabolites, and other uremic factors. Vascular calcification can occur in the intima and the media of arterial wall. Under permissive conditions, vascular smooth muscle cells (VSMCs) can transform to osteoblast-like phenotype. The membrane-bound vesicles released from transformed VSMCs and the apoptotic bodies derived from dying VSMCs serve as nucleating structures for calcium crystal formation. Alterations in the quality and the quantity of endogenous calcification inhibitors also give rise to an environment that potentiates calcification.

Atherosclerosis in Chronic Kidney Disease: More, Less, or Just Different?

Patients with chronic kidney disease (CKD) are at an increased risk of premature mortality, mainly from cardiovascular causes. The association between CKD on hemodialysis and accelerated atherosclerosis was described >40 years ago. However, more recently, it has been suggested that the increase in atherosclerosis risk is actually observed in early CKD stages, remaining stable thereafter. In this regard, interventions targeting the pathogenesis of atherosclerosis, such as statins, successful in the general population, have failed to benefit patients with very advanced CKD. This raises the issue of the relative contribution of atherosclerosis versus other forms of cardiovascular injury such as arteriosclerosis or myocardial injury to the increased cardiovascular risk in CKD. In this review, the pathophysiogical contributors to atherosclerosis in CKD that are shared with the general population, or specific to CKD, are discussed. The NEFRONA study (Observatorio Nacional de Atherosclerosis en NEFrologia) prospectively assessed the prevalence and progression of subclinical atherosclerosis (plaque in vascular ultrasound), confirming an increased prevalence of atherosclerosis in patients with moderate CKD. However, the adjusted odds ratio for subclinical atherosclerosis increased with CKD stage, suggesting a contribution of CKD itself to subclinical atherosclerosis. Progression of atherosclerosis was closely related to CKD progression as well as to the baseline presence of atheroma plaque, and to higher phosphate, uric acid, and ferritin and lower 25(OH) vitamin D levels. These insights may help design future clinical trials of stratified personalized medicine targeting atherosclerosis in patients with CKD. Future primary prevention trials should enroll patients with evidence of subclinical atherosclerosis and should provide a comprehensive control of all known risk factors in addition to testing any additional intervention or placebo.

Machine learning analysis of serum biomarkers for cardiovascular risk assessment in chronic kidney disease

Background

Chronic kidney disease (CKD) patients show an increased burden of atherosclerosis and high risk of cardiovascular events (CVEs). There are several biomarkers described as being associated with CVEs, but their combined effectiveness in cardiovascular risk stratification in CKD has not been tested. The objective of this work is to analyse the combined ability of 19 biomarkers associated with atheromatous disease in predicting CVEs after 4 years of follow-up in a subcohort of the NEFRONA study in individuals with different stages of CKD without previous CVEs.

Methods

Nineteen putative biomarkers were quantified in 1366 patients (73 CVEs) and their ability to predict CVEs was ranked by random survival forest (RSF) analysis. The factors associated with CVEs were tested in Fine and Gray (FG) regression models, with non-cardiovascular death and kidney transplant as competing events.

Results

RSF analysis detected several biomarkers as relevant for predicting CVEs. Inclusion of those biomarkers in an FG model showed that high levels of osteopontin, osteoprotegerin, matrix metalloproteinase-9 and vascular endothelial growth factor increased the risk for CVEs, but only marginally improved the discrimination obtained with classical clinical parameters: concordance index 0.744 (95% confidence interval 0.609–0.878) versus 0.723 (0.592–0.854), respectively. However, in individuals with diabetes treated with antihypertensives and lipid-lowering drugs, the determination of these biomarkers could help to improve cardiovascular risk estimates.

Conclusions

We conclude that the determination of four biomarkers in the serum of CKD patients could improve cardiovascular risk prediction in high-risk individuals.

Subclinical atherosclerosis burden predicts cardiovascular events in individuals with diabetes and chronic kidney disease

BACKGROUND

Individuals with diabetes have remarkably high rates of cardiovascular morbidity and mortality. However, the incremental cardiovascular risk in diabetes is heterogeneous and has often been related to renal involvement. The purpose of this study was to analyse the prognostic value of subclinical atherosclerosis in determining the incidence of first cardiovascular events (CVEs) in individuals with diabetes and chronic kidney disease (CKD) compared to CKD individuals without diabetes.

METHODS

We included data from individuals with CKD with and without diabetes, free from pre-existing cardiovascular disease, from the NEFRONA cohort. Participants underwent baseline carotid and femoral ultrasound and were followed up for 4 years. All CVEs during follow-up were registered. Bivariate analysis and Fine-Gray competing risk models were used to perform the statistical analysis.

RESULTS

During the mean follow-up time of 48 months, a total of 203 CVE was registered. 107 CVE occurred among participants without diabetes (19.58 per 1000 person-years) and 96 CVE occurred among participants with diabetes (44.44 per 1000 person-years). Following the competing risk analysis, the variables predicting CVEs in CKD individuals without diabetes were the number of territories with plaque at baseline (HR 1.862, 95% CI [1.432;2.240]), age (HR 1.026, 95% CI [1.003;1.049]) and serum concentrations of 25-OH vitamin D (HR 0.963, 95% CI [0.933;0.094]). The only variable predicting CVEs among CKD participants with diabetes was the number of territories with plaque at baseline (HR 1.782, 95% CI [1.393, 2.278]). For both models, concordance (C) index yielded was over 0.7.

CONCLUSIONS

The burden of subclinical atherosclerosis is the strongest predictor of future CVEs in diabetic individuals with CKD. Early detection of subclinical atherosclerotic burden by multiterritorial vascular ultrasound could improve CVE prediction in this population.

An in-depth analysis shows a hidden atherogenic lipoprotein profile in non-diabetic chronic kidney disease patients

Background: Chronic kidney disease (CKD) is an independent risk factor for atherosclerotic disease. We hypothesized that CKD promotes a proatherogenic lipid profile modifying lipoprotein composition and particle number. Methods: Cross-sectional study in 395 non-diabetic individuals (209 CKD patients and 186 controls) without statin therapy. Conventional lipid determinations were combined with advanced lipoprotein profiling by nuclear magnetic resonance, and their discrimination ability was assessed by machine learning. Results: CKD patients showed an increase of very-low-density (VLDL) particles and a reduction of LDL particle size. Cholesterol and triglyceride content of VLDLs and intermediate-density (IDL) particles increased. However, low-density (LDL) and high-density (HDL) lipoproteins gained triglycerides and lost cholesterol. Total-Cholesterol, HDL-Cholesterol, LDL-Cholesterol, non-HDL-Cholesterol and Proprotein convertase subtilisin-kexin type (PCSK9) were negatively associated with CKD stages, whereas triglycerides, lipoprotein(a), remnant cholesterol, and the PCSK9/LDL-Cholesterol ratio were positively associated. PCSK9 was positively associated with total-Cholesterol, LDL-Cholesterol, LDL-triglycerides, LDL particle number, IDL-Cholesterol, and remnant cholesterol. Machine learning analysis by random forest revealed that new parameters have a higher discrimination ability to classify patients into the CKD group, compared to traditional parameters alone: area under the ROC curve (95% CI), .789 (.711, .853) vs .687 (.611, .755). Conclusions: non-diabetic CKD patients have a hidden proatherogenic lipoprotein profile.

The rs1126616 Single Nucleotide Polymorphism of the Osteopontin Gene Is Independently Associated with Cardiovascular Events in a Chronic Kidney Disease Cohort

Chronic kidney disease (CKD) is associated with a higher risk of cardiovascular events (CVE), partly due to the higher burden of atherosclerosis. Circulating Osteopontin (OPN) levels have been also shown to have a potential role in the development of atherosclerosis. Indeed, CKD patients show an increase in circulating OPN levels, but their effect of CKD-related atherosclerosis is not clear. Polymorphisms in the OPN gene (SPP1) have been studied in atheromatous disease, but reported results show conflictive findings. Thus, the main aim of the present study is to analyze the influence of SPP1 polymorphisms in CVE in CKD patients, taking into account circulating OPN levels. We followed 559 healthy controls and 2445 CKD patients without previous CVE from the National Observatory of Atherosclerosis in Nephrology study (NEFRONA study). After 48 months of follow-up 206 CVE were recorded. Genotyping for rs9138, rs1126616, rs1126772, rs11730582 and rs28357094 polymorphisms of the SPP1 gene was performed along with the measurements of plasma OPN levels. The group of patients with CVE showed higher incidence of atherosclerotic plaque (90.3% vs 64.5%; p < 0.001) and higher OPN levels (p < 0.001) at baseline. Patients with the heterozygous genotype of the rs1126616 polymorphism showed a higher hazard ratio of having a CVE, even after adjustment for multiple potential confounders. After adjustment, OPN levels were no longer associated with the incidence of CVE. We found that the rs1126616 single nucleotide polymorphism (SNP) of the SPP1 gene is independently associated with a higher incidence of CVE in a cohort of CKD patients and that it could be used to predict CVE risk.

Relationship between low levels of circulating TRAIL and atheromatosis progression in patients with chronic kidney disease

Background

Chronic kidney disease (CKD) patients experience a high risk of cardiovascular disease (CV); however, the factors involved in CV-related morbidity and mortality in these patients have not been fully defined. Tumor necrosis factor related apoptosis-inducing ligand (TRAIL) is a cytokine, which exhibits pleiotropic activities on endothelial, vascular smooth muscle and inflammatory cells, with relevant effects on atheromatous plaque formation. On this basis, the present study aims to investigate the role of TRAIL in atheromatosis progression in CKD patients.

Methods

Circulating TRAIL levels were measured in 378 CKD patients belonging to the Spanish National Observatory of Atherosclerosis in Nephrology (NEFRONA) study. All patients were free of previous CV events. Carotid and femoral B-mode ultrasound was performed to detect the presence of plaque at baseline and after 24 months of follow-up.

Results

The lowest levels of TRAIL at baseline were significantly (p<0.05) associated with the appearance, after 24 months of follow-up, of at least two new atheromatous plaques in all territories and of one new plaque in the carotid artery, even after adjusting for CV risk factors. In addition, the patients with low levels of TRAIL at baseline were characterized by the presence of at least one hypoechoic plaque in the carotid artery. This association was significant (p<0.05) even after adjusting for CKD stage.

Conclusions

Overall, the results of our study suggest TRAIL as an assertable independent prognostic biomarker for atheromatosis plaque formation in CKD patients. This observation further supports the potential role of TRAIL for the prevention/treatment of CV disease.

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

Background

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

Methods

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

Results

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

Conclusions

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

Soluble Tumor Necrosis Factor Like Weak Inducer of Apoptosis and Vitamin D in Hemodialysis Patients: Relation to Carotid Intima-Media Thickness

Cardiovascular disease, as the leading cause of patient death with chronic kidney disease, could be predicted by carotid atherosclerosis. The aim of the present study was to evaluate a possible relationship between serum soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) and Vitamin D levels with mean right/left carotid intima-media thickness (cIMT), in the hemodialysis (HD) patients. In this cross-sectional study, serums were obtained from 50 stable chronic HD patients and 39 healthy controls. The serum levels of sTWEAK, Vitamin D, intact parathyroid hormone (iPTH) in both groups, and cIMT were determined in HD patients by standard methods. Serum levels of sTWEAK were higher [808.8 (521.6-5032.4) pg/ml vs. 664.4 (487.4-2955.8) pg/ml (p = 0.006)] and Vitamin D levels were lower [13.4 (2.5-153) ng/ml vs. 27.8 (18.4-59.0) ng/ml (p = 0.001)] in the hemodialysis patients than in the healthy control. No important correlation was found between sTWEAK Vitamin D levels (r = 0.010/p = 0.946), and mean right(r = -0.194/p = 0.178) and left (r = 0.061/p = 0.673) cIMT in the HD patients. Our study shows that sTWEAK levels are elevated in HD patients. This elevation has no association with the cIMT.

Prevalence and progression of subclinical atherosclerosis in patients with chronic kidney disease and diabetes

BACKGROUND AND AIMS

Cardiovascular disease is the leading cause of morbidity and mortality in patients with chronic kidney disease (CKD) and diabetes. Traditional cardiovascular risk factors fail to fully account for the increase in cardiovascular risk in these patients. This study aims to analyse the prevalence and progression of subclinical atherosclerosis in CKD patients with and without diabetes.

METHODS

We included data from CKD patients with and without diabetes free from previous cardiovascular events from the NEFRONA cohort. Patients underwent baseline and 24-month follow-up carotid and femoral ultrasound examinations. Multivariable models were used to assess the contribution of diabetes to the presence and plaque progression.

RESULTS

A total of 419 patients with diabetes and 1129 without diabetes were included. Diabetic patients were older, had higher BMIs, more hypertension and dyslipidaemia. At baseline, the proportion of patients with plaque was higher among diabetic patients (81.4% vs. 64.1%, p < 0.001). Diabetic patients more frequently had more than two vascular territories with plaque (64.4% vs. 48.4%, p < 0.001). Multivariable analysis indicated that plaque at baseline was significantly associated with age, gender, smoking and renal replacement therapy (RRT) in the non-diabetic patients, but only with age and male gender in diabetic patients. Plaque progression was significantly associated with age, number of territories with basal plaque, smoking and RRT in both groups.

CONCLUSIONS

Subclinical atherosclerosis is more prevalent, carries a higher plaque burden and is more rapidly progressive in renal patients with diabetes. In these patients, diabetes outweighs other described risk factors associated with the presence of subclinical atherosclerosis.

Association of the rs495392 Klotho polymorphism with atheromatosis progression in patients with chronic kidney disease

Background

Prevalence of atherosclerotic cardiovascular disease and its rate of progression are higher in patients with chronic kidney disease (CKD) compared with the general population. Mineral metabolism parameters have been shown to be involved in the increased velocity of atheromatosis progression. The aim of this study is to determine the role of 11 single-nucleotide polymorphisms (SNPs) of the Klotho gene on the rate of atherosclerosis progression in CKD.

Methods

This was a multicentre, prospective, observational study of 1439 CKD patients from the NEFRONA cohort. Carotid and femoral ultrasounds were performed at baseline and after 24 months in 10 arterial territories. Progression of atheromatosis was defined as an increase in the number of territories with plaque. Genotyping of 11 SNPs of the Klotho gene was performed and its association with atheromatosis progression was determined by multivariate logistic regression.

Results

Bivariate analysis showed that none of the 11 SNPs was associated with atheroma plaque prevalence, but 3 of them (rs495392, rs562020 and rs567170) showed association with atheromatosis progression. The multivariate analysis revealed that only rs495392 showed a statistically significant association with atheromatosis progression, after adjustment for several parameters known to affect it in CKD patients. Thus, the presence of one allele T was associated with a reduction of 30% of the odds of progression, whereas the presence of the two T alleles was associated with a decrease close to 50%.

Conclusions

The presence of the allele T of the SNP rs495392 of the Klotho gene is associated with a decrease in the odds of progression of atheromatosis in CKD patients.

Serum markers for asymptomatic atherosclerosis in Egyptian psoriatic patients: study controlled by Doppler estimation of carotid intima-media thickness

Background

The aim of the study was to measure serum levels of endocan, myeloperoxidase (MPO), pentraxin 3 (PTX3) and 1,25-dihydroxyvitamin D3 (1,25(OH)₂D₃) in psoriatic patients and to study their correlations with carotid intima-media thickness (CIMT) in trial to evaluate predictability of these parameters in diagnosing asymptomatic atherosclerosis (AAS).

Patients and methods

Seventy-five psoriasis patients and 75 control subjects underwent complete clinical examination and Doppler estimation of CIMT using thickness of 0.9 mm as cutoff point for diagnosis of AAS. Blood samples were collected for determination of fasting blood glucose, lipid profile and serum C-reactive protein (CRP), endocan, MPO, PTX3 and 1,25(OH)₂D₃.

Results

Estimated blood low-density lipoprotein cholesterol (LDL-c) and serum CRP, PTX3, MPO and endocan levels were significantly higher, while blood high-density lipoprotein cholesterol (HDL-c) and serum 1,25(OH)₂D₃ levels were significantly lower in patients than in controls. CIMT showed significant positive correlation with disease severity and duration; patients’ age; and endocan, MPO, LDL-c, PTX3 and CRP levels, and significant negative correlation with HDL-c and 1,25(OH)₂D₃ levels. Regression analysis defined high serum endocan and MPO, low serum 1,25(OH)₂D₃ and increased disease severity as significant predictors of high CIMT.

Conclusion

Elevated serum levels of endocan and MPO and low 1,25(OH)₂D₃ levels may underlie the development of psoriasis-related cardiac manifestations. Elevated serum endocan and low 1,25(OH)₂D₃ levels could be used as early predictors of increased CIMT, which is a pathognomonic feature of AAS.

Relationship of femoral artery ultrasound measures of atherosclerosis with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is strongly associated with peripheral artery disease (PAD). Detection of subclinical PAD may allow early interventions for or prevention of PAD in persons with CKD. Whether the presence of atherosclerotic plaque and femoral intima-media thickness (IMT) are associated with kidney function is unknown.

METHODS

We performed a cross-sectional observational study of 1029 community-living adults. We measured superficial and common femoral artery IMT and atherosclerotic plaque presence by ultrasound. Estimated glomerular filtration rate (eGFR; continuous) and eGFR <60 mL/min/1.73 m2 (binary) were evaluated as outcomes.

RESULTS

Mean age was 70 ± 10 years, mean eGFR was 78 ± 17 mL/min/1.73 m2, and 156 (15%) individuals had eGFR <60 mL/min/1.73 m2; 260 (25%) had femoral artery plaque. In models adjusted for demographics and cardiovascular risk factors, individuals with femoral artery plaque had mean eGFR approximately 3.0 (95% confidence interval, -5.3 to -0.8) mL/min/1.73 m2 lower than those without plaque (P < .01). The presence of plaque was also associated with a 1.7-fold higher odds of eGFR <60 mL/min/1.73 m2 (95% confidence interval, 1.1-2.8; P < .02). Associations were similar in persons with normal ankle-brachial index. The directions of associations were similar for femoral IMT measures with eGFR and CKD but were rendered no longer statistically significant with adjustment for demographic variables and cardiovascular disease risk factors.

CONCLUSIONS

Femoral artery plaque is significantly associated with CKD prevalence in community-living individuals, even among those with normal ankle-brachial index. Femoral artery ultrasound may allow evaluation of relationships and risk factors linking PAD and kidney disease earlier in its course.

Association of FGF-2 Concentrations with Atheroma Progression in Chronic Kidney Disease Patients

BACKGROUND AND OBJECTIVES

Atherosclerosis is highly prevalent in CKD. The rate of progression of atherosclerosis is associated with cardiovascular events. Fibroblast growth factor 2 (FGF-2) is a member of the FGF family with potentially both protective and deleterious effects in the development of atherosclerosis. The role of circulating FGF-2 levels in the progression of atherosclerosis in CKD is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used a multicenter, prospective, observational cohorts study of 481 patients with CKD. We determined the presence of atheroma plaque in ten arterial territories by carotid and femoral ultrasounds. Progression of atheromatosis was defined as an increase in the number of territories with plaque after 24 months. Plasma levels of FGF-2 were measured by multiplex analysis. A multivariable logistic regression analysis was performed to determine whether plasma FGF-2 levels were associated with atheromatosis progression.

RESULTS

Average age of the population was 61 years. The percentage of patients in each CKD stage was 51% in stage 3, 41% in stages 4-5, and 8% in dialysis. A total of 335 patients (70%) showed plaque at baseline. Atheromatosis progressed in 289 patients (67%). FGF-2 levels were similar between patients with or without plaque at baseline (79 versus 88 pg/ml), but lower in patients with atheromatosis progression after 2 years (78 versus 98 pg/ml; P<0.01). In adjusted analyses, higher plasma FGF-2 was associated with lower risk of atheromatosis progression (odds ratio [OR], 0.86; 95% confidence interval [95% CI], 0.76 to 0.96; per 50 pg/ml increment). Analysis of FGF-2 in tertiles showed that atheroma progression was observed for 102 participants in the lowest tertile of FGF-2 (reference group), 86 participants in the middle tertile of FGF-2 (adjusted OR, 0.70; 95% CI, 0.40 to 1.20), and 74 participants in the lowest tertile of FGF-2 (adjusted OR, 0.48; 95% CI, 0.28 to 0.82).

CONCLUSIONS

Low FGF-2 levels are independently associated with atheromatosis progression in CKD.

The modality of dialysis does not influence atheromatous vascular disease progression or cardiovascular outcomes in dialysis patients without previous cardiovascular disease

BACKGROUND

There is limited and inconclusive information regarding the influence of the modality of renal replacement therapy on the atherosclerotic burden of patients on dialysis. The aim of this study was to compare the prevalence of asymptomatic atheromatous carotid disease, as also its rate of progression and cardiovascular outcomes, in two matched populations of patients treated with hemodialysis (HD) and peritoneal dialysis (PD).

METHODS

Following a prospective, observational and multicenter design, we compared 237 PD and 237 HD patients without previous cardiovascular disease, included in the NEFRONA study, and matched for age, sex, diabetes and time on dialysis. Carotid ultrasound study was performed at baseline and after two years of follow-up in 6 carotid territories. Atheromatous vascular disease (AVD) progression was defined as any increase in the number of territories with plaques after 2 years. Fatal and non fatal cardiovascular events were also recorded during 36-month of follow-up.

MAIN RESULTS

At baseline, PD patients presented a worse general cardiovascular risk profile than HD patients. On the contrary, some markers of prevalent atherosclerotic disease (common carotid intima-media thickness and ankle-brachial index) were more favorable in PD patients. During follow-up, we observed no differences either in the rate of progression of atheromatous vascular disease (OR 1.78, 95% CI 0.80-4.06, p = 0.161) or in the incidence of cardiovascular events (OR 1.51, 95% CI 0.85-2.66, p = 0.159), according to the modality of dialysis.

CONCLUSION

Dialysis modality did not impact on atherosclerotic carotid disease progression or cardiovascular outcomes, in two groups of patients treated with PD or HD.

Factors predicting cardiovascular events in chronic kidney disease patients. Role of subclinical atheromatosis extent assessed by vascular ultrasound

Patients with chronic kidney disease (CKD) have an increased incidence of cardiovascular events (CVE). The contribution of subclinical atheromatosis extent, including femoral arteries, to CVE in CKD patients has not been investigated. In this paper, we examine the prognostic value of subclinical atheromatosis extent, assessed as the number of arterial territories with plaque, in predicting the incidence of major and minor CVE. The NEFRONA is a multicenter, prospective cohorts study that recruited 2445 CKD subjects and 559 controls, free from previous cardiovascular disease, in 81 medical centers across Spain. The presence of atheroma plaque was assessed by arterial ultrasound in ten arterial territories (carotid and femoral). The predictive power of the presence or absence of atheroma plaque in any territory was compared with the quantification of atheroma extent as the number of territories with plaque. During the median follow up of 48 months, 216 CVE were reported. Factors predicting the incidence of CVE in the whole cohort were being male, CKD patient, lower levels of 25(OH) vitamin D, higher levels of cholesterol and the extent of subclinical atheromatosis, yielding a higher concordance (C) index than the presence or absence of plaque. In stratified analysis including specific factors of CKD patients not on dialysis, the variables predicting CVE were the same as in the whole cohort, plus higher levels of potassium. Again, the inclusion of the information about atheromatosis as number of territories with plaque, presented a higher C index than the presence or absence of plaque. In the dialysis population, significant variables were older age, diabetes, dialysis vintage and higher levels of cholesterol and phosphate. In this case the higher C index was obtained with the information about plaque presence.

Subclinical atheromatosis extent, including femoral arteries, influences CVE in CKD and its detection could improve the prediction of cardiovascular events.

New perspectives on CKD-induced dyslipidemia

INTRODUCTION

Chronic kidney disease (CKD) is a world-wide health concern associated with a significantly higher cardiovascular morbidity and mortality. One of the principal cardiovascular risk factors is the lipid profile. CKD patients have a more frequent and progressive atheromatous disease that cannot be explained by the classical lipid parameters used in the daily clinical practice. Areas covered: The current review summarizes prevailing knowledge on the role of lipids in atheromathosis in CKD patients, including an overview of lipoprotein metabolism highlighting the CKD-induced alterations. Moreover, to obtain information beyond traditional lipid parameters, new state-of-the-art technologies such as lipoprotein subfraction profiling and lipidomics are also reviewed. Finally, we analyse the potential of new lipoprotein subclasses as therapeutic targets in CKD. Expert opinion: The CKD-induced lipid profile has specific features distinct from the general population. Besides quantitative alterations, renal patients have a plethora of qualitative lipid alterations that cannot be detected by routine determinations and are responsible for the excess of cardiovascular risk. New parameters, such as lipoprotein particle number and size, together with new biomarkers obtained by lipidomics will personalize the management of these patients. Therefore, nephrologists need to be aware of new insights into lipoprotein metabolism to improve cardiovascular risk assessment.

Association between serum 25-hydroxyvitamin D levels and carotid atherosclerosis in chronic kidney disease patients

Background

Epidemiological studies have shown an inverse relationship between vitamin D levels and cardiovascular diseases. However, this does not infer a causal relationship between the two. Chronic kidney disease (CKD) patients have a high prevalence of vitamin D deficiency and carotid atherosclerosis. Therefore, in this study we have aimed to determine the association between serum 25-hydroxyvitamin D levels and carotid atherosclerosis in the CKD population.

Methods

100 CKD stage 3–4 patients were included in the study. Direct chemiluminesent immunoassay was used to determine the level of serum 25-hydroxyvitamin D. All subjects underwent a carotid ultrasound to measure common carotid artery intima-media thickness (CCA-IMT) and to assess the presence of carotid plaques or significant stenosis (≥50 %). Vitamin D deficiency was defined as serum 25-hydroxyvitamin D < 25 nmol/L. Abnormal CCA-IMT was defined as CCA-IMT ≥ 0.8 mm. Plaque was defined as a focal structure that encroaches into the arterial lumen of ≥ 0.5 mm or 50 % of the surrounding IMT value. Significant stenosis was defined as peak-systolic velocities ≥ 125 cm/s and end-diastolic velocities ≥ 40 cm/s.

Results

The vitamin D deficiency and non-deficiency groups did not differ significantly in terms of abnormal CCA-IMT (P = 0.443), carotid plaque (P = 0.349), and carotid stenosis (P = 0.554). No significant correlation between serum 25-hydroxyvitamin D levels and CCA-IMT (P = 0.693) was found. On a backward multiple linear regression model, serum 25-hydroxyvitamin D levels was not associated with CCA-IMT, abnormal CCA-IMT, or plaque presence.

Conclusions

No important association between serum 25-hydroxyvitamin levels and carotid atherosclerosis was found in CKD patients.

Determinants of thromboxane biosynthesis in patients with moderate to severe chronic kidney disease

BACKGROUND

Mechanisms of accelerated atherothrombosis in patients with chronic kidney disease (CKD) are only partly characterized. The aims of this study were to evaluate the extent of thromboxane (TX)-dependent platelet activation in patients with CKD, and to characterize the determinants of altered TX biosynthesis in this setting, with particular reference to enhanced lipid peroxidation, low grade inflammation and CKD-related anemia.

PATIENTS AND METHODS

A cross sectional comparison between urinary 8-iso-PGF2α and 11-dehydro-TXB2, in vivo markers of oxidative stress and platelet activation, respectively, was performed in 115 patients with stage 1-4 CKD.

RESULTS

Levels of both urinary 11-dehydro-TXB2 and 8-iso-PGF2α increased sequentially across the four CKD stages (P<0.0001, Kruskal-Wallis test). Both urinary prostanoids were inversely associated with either estimated glomerular filtration rate (eGFR, P<0.0001) or hemoglobin levels (P<0.0001). A significant direct correlation was also observed between urinary 11-dehydro-TXB2 and 8-iso-PGF2α (Rho=0.620, P<0.0001). On multivariate analysis, urinary 8-iso-PGF2α (β=0.459, P<0.0001), hemoglobin levels (β=- 0.261, P=0.002) and eGFR (β=-0.172, P=0.032) were independent predictors of urinary 11-dehydro-TXB2 (adjusted R(2)=0.488).

CONCLUSIONS

This study provides biochemical evidence of persistent platelet activation in patients with CKD. This condition occurs early in the natural history of the disease and is related to kidney function and oxidative stress. Moreover, we found an independent inverse relationship between hemoglobin levels and TX-dependent platelet activation. This finding may provide a mechanistic link between CKD-related anemia and increased cardiovascular risk.

Quality Assurance of Samples and Processes in the Spanish Renal Research Network (REDinREN) Biobank

BACKGROUND

Biobanks are useful platforms to build bridges between basic, translational, and clinical research and clinical care. They are repositories of high-quality human biological samples ideal for evaluating their histological characteristics and also their genome, transcriptome, and proteome. The Spanish Renal Research Network Biobank contains more than 76,500 well-preserved frozen samples of a wide variety of kidney diseases, collected from 5450 patients seen by over 70 nephrology services throughout the Spanish territory.

OBJECTIVE

To determine and to report the results of the quality control of samples and processes conducted in our biobank, implemented in accordance with the requirements of the ISO 9001:2008 international standard.

STUDY DESIGN

Two types of quality controls were performed: (1) systematic, that is, measurement of viable peripheral blood mononuclear cells (PBMCs) obtained and purity of nucleic acids and (2) ad-hoc, that is, viability of thawed PBMC, DNA extraction process reproducibility, and the integrity and functionality of nucleic acids, implemented on a routine basis.

METHODS AND RESULTS

PBMC isolation by Ficoll yielded reproducible results and its cryopreserved viability was >90%. Acceptable A260/A280 ratios were obtained for the vast majority of the DNA (n = 2328) and RNA (n = 78) samples analyzed. DNA integrity was demonstrated by agarose gels and by β-globulin gene polymerase chain reaction (PCR) amplification of 1327 and 989 bp fragments. DNA of acceptable quality had at least three bands of β-globulin amplified obtained (n = 26/30). RNA integrity number (RIN) determinations obtained RIN numbers ≥7 (n = 87/96). The amplifiability of nucleic acids was confirmed by qPCR and RT-qPCR of β-actin and GAPDH genes. Long storage or delayed processing time did not affect the quality of the samples analyzed. The processes of DNA extraction also yielded reproducible results.

CONCLUSIONS

These results clearly indicate that our PBMC, DNA, and RNA stored samples meet the required quality standards to be used for biomedical research, ensuring their long-term preservation.