High-Density Lipoprotein Subfractions and Their Oxidized Subfraction Particles in Patients with Chronic Kidney Disease

Effects of turmeric extract supplementation on the lipid and lipoprotein subfraction profile in hemodialysis patients: A randomised, double-blind, crossover and controlled trial

Dyslipidemia is common in patients with chronic kidney disease. Curcumin, a bioactive polyphenol from Curcuma longa, can improve lipid profile. This study aims to analyze the effects of Curcuma Longa extract supplementation on lipid profile and lipoprotein subfractions in hemodialysis (HD) patients. This is a longitudinal, double-blind, washout-period randomized clinical trial. The patients were randomized into two groups: the curcumin group (n = 10) (orange and carrot juice with 2.5 g of Curcuma Longa extract) and the control group (n = 11) (juice without curcumin) 3x/w during HD sessions for 3 months. After the washout period, patients continued the supplementation as a crossover for the same period. The lipid profile was measured using enzymatic assays. The high-density lipoprotein and low-density lipoprotein subfractions analyses were performed using LipoprintTM. In the curcumin group, the triglyceride values tended to decrease with a different triglyceride variation between the pre and post-intervention for the control and curcumin groups of 38.5 (19.8) mg/dL (p = 0.06). There was no statistical difference in the others parameters. In conclusion, Curcuma longa extract may be a good nutritional strategy to reduce triglyceride plasma levels in hemodialysis patients, but it seems ineffective for the other parameter.

Adsorption of Acylhydroperoxy-Derivatives of Phospholipids from Biomembranes by Blood Plasma Lipoproteins

It has been established that acylhydroperoxy derivatives of phospholipids from oxidized rat liver mitochondria are captured predominantly by LDL particles but not by HDL during co-incubation with blood plasma lipoproteins, which refutes the previously suggested hypothesis about the involvement of HDL in the reverse transport of oxidized phospholipids and confirms the possibility of different mechanisms of lipohydroperoxide accumulation in LDL during oxidative stress.

Expanding the Molecular Disturbances of Lipoproteins in Cardiometabolic Diseases: Lessons from Lipidomics

The increasing global burden of cardiometabolic diseases highlights the urgent clinical need for better personalized prediction and intervention strategies. Early diagnosis and prevention could greatly reduce the enormous socio-economic burden posed by these states. Plasma lipids including total cholesterol, triglycerides, HDL-C, and LDL-C have been at the center stage of the prediction and prevention strategies for cardiovascular disease; however, the bulk of cardiovascular disease events cannot be explained sufficiently by these lipid parameters. The shift from traditional serum lipid measurements that are poorly descriptive of the total serum lipidomic profile to comprehensive lipid profiling is an urgent need, since a wealth of metabolic information is currently underutilized in the clinical setting. The tremendous advances in the field of lipidomics in the last two decades has facilitated the research efforts to unravel the lipid dysregulation in cardiometabolic diseases, enabling the understanding of the underlying pathophysiological mechanisms and identification of predictive biomarkers beyond traditional lipids. This review presents an overview of the application of lipidomics in the study of serum lipoproteins in cardiometabolic diseases. Integrating the emerging multiomics with lipidomics holds great potential in moving toward this goal.

Association of Kidney Function With NMR-Quantified Lipids, Lipoproteins, and Metabolic Measures in Mexican Adults

CONTEXT

Chronic kidney disease (CKD) and diabetes are associated with dyslipidemia, metabolic abnormalities, and atherosclerotic risk. Nuclear magnetic resonance (NMR) spectroscopy provides much more detail on lipoproteins than traditional assays.

METHODS

In about 38 000 participants from the Mexico City Prospective Study, aged 35 to 84 years and not using lipid-lowering medication, NMR spectroscopy quantified plasma concentrations of lipoprotein particles, their lipidic compositions, and other metabolic measures. Linear regression related low estimated glomerular filtration rate (eGFR; <60 mL/min/1.73 m2) to each NMR measure after adjustment for confounders and for multiplicity. Analyses were done separately for those with and without diabetes.

RESULTS

Among the 38 081 participants (mean age 52 years, 64% women), low eGFR was present for 4.8% (306/6403) of those with diabetes and 1.2% (365/31 678) of those without diabetes. Among both those with and without diabetes, low eGFR was significantly associated with higher levels of 58 NMR measures, including apolipoprotein B (Apo-B), the particle numbers of most Apo-B containing lipoproteins, the cholesterol and triglycerides carried in these lipoproteins, several fatty acids, total cholines and phosphatidylcholine, citrate, glutamine, phenylalanine, β-OH-butyrate, and the inflammatory measure glycoprotein-A, and significantly lower levels of 13 NMR measures, including medium and small high-density lipoprotein particle measures, very low-density lipoprotein particle size, the ratio of saturated:total fatty acids, valine, tyrosine, and aceto-acetate.

CONCLUSIONS

In this Mexican population with high levels of adiposity and diabetes, low kidney function was associated with widespread alterations in lipidic and metabolic profiles, both in those with and without diabetes. These alterations may help explain the higher atherosclerotic risk experienced by people with CKD.

Subpopulations of High-Density Lipoprotein: Friends or Foes in Cardiovascular Disease Risk in Chronic Kidney Disease?

Dyslipidemia is a major traditional risk factor for cardiovascular disease (CVD) in chronic kidney disease (CKD) patients, although the altered lipid profile does not explain the number and severity of CVD events. High-density lipoprotein (HDL) is a heterogeneous (size, composition, and functionality) population of particles with different atherogenic or atheroprotective properties. HDL-cholesterol concentrations per se may not entirely reflect a beneficial or a risk profile for CVD. Large HDL in CKD patients may have a unique proteome and lipid composition, impairing their cholesterol efflux capacity. This lack of HDL functionality may contribute to the paradoxical coexistence of increased large HDL and enhanced risk for CVD events. Moreover, CKD is associated with inflammation, oxidative stress, diabetes, and/or hypertension that are able to interfere with the anti-inflammatory, antioxidative, and antithrombotic properties of HDL subpopulations. How these changes interfere with HDL functions in CKD is still poorly understood. Further studies are warranted to fully clarify if different HDL subpopulations present different functionalities and/or atheroprotective effects. To achieve this goal, the standardization of techniques would be valuable.

The Role and Function of HDL in Patients with Chronic Kidney Disease and the Risk of Cardiovascular Disease

Chronic kidney disease (CKD) is a worldwide health problem with steadily increasing occurrence. Significantly elevated cardiovascular morbidity and mortality have been observed in CKD. Cardiovascular diseases are the most important and frequent cause of death of CKD patients globally. The presence of CKD is related to disturbances in lipoprotein metabolism whose consequences are dyslipidemia and the accumulation of atherogenic particles. CKD not only fuels the reduction of high-density lipoprotein (HDL) cholesterol concentration, but also it modifies the composition of this lipoprotein. The key role of HDL is the participation in reverse cholesterol transport from peripheral tissues to the liver. Moreover, HDL prevents the oxidation of low-density lipoprotein (LDL) cholesterol by reactive oxygen species (ROS) and protects against the adverse effects of oxidized LDL (ox-LDL) on the endothelium. Numerous studies have demonstrated the ability of HDL to promote the production of nitric oxide (NO) by endothelial cells (ECs) and to exert antiapoptotic and anti-inflammatory effects. Increasing evidence suggests that in patients with chronic inflammatory disorders, HDLs may lose important antiatherosclerotic properties and become dysfunctional. So far, no therapeutic strategy to raise HDL, or alter the ratio of HDL subfractions, has been successful in slowing the progression of CKD or reducing cardiovascular disease in patients either with or without CKD.

The influence of hemodialysis on FibroTest parameters

Chronic hepatitis C viral infection is an important cause of morbidity and mortality in patients with end-stage renal disease treated with hemodialysis. Liver fibrosis represents a main determinant of liver disease prognosis and clinical management, and its assessment by liver biopsy can decide treatment allocation. Although liver biopsy is the gold standard for staging liver fibrosis, it is an invasive procedure associated with complications that are more prevalent in patients with end-stage renal disease. FibroTest represents a surrogate marker of fibrosis which evaluates the levels of apolipoprotein A1, total bilirubin, haptoglobin, gamma-glutamyltransferase and α2-macroglobulin, generating a score that indicates the level of fibrosis. Discrepancies were observed in clinical practice between FibroTest score and histopathological findings. The aim of this study was to evaluate how hemodialysis influences the level of each FibroTest parameter and the final score. The systematic literature review conducted by us suggests that hemodialysis induces a reduction in apolipoprotein A1, haptoglobin and bilirubin levels, with an increase in gamma-glutamyltransferase and alpha-2-macroglobulin levels. In conclusion, hemodialysis modifies the levels of FibroTest parameters, suggesting that it may also have an impact on the accuracy of liver fibrosis assessment in hemodialysis patients.

Biological Consequences of Dysfunctional HDL

Epidemiological studies have suggested an inverse correlation between high-density lipoprotein (HDL) cholesterol levels and the risk of cardiovascular disease. HDLs promote reverse cholesterol transport (RCT) and possess several putative atheroprotective functions, associated to the anti-inflammatory, anti-thrombotic and anti-oxidant properties as well as to the ability to support endothelial physiology. The assumption that increasing HDL-C levels would be beneficial on cardiovascular disease (CVD), however, has been questioned as, in most clinical trials, HDL-C-raising therapies did not result in improved cardiovascular outcomes. These findings, together with the observations from Mendelian randomization studies showing that polymorphisms mainly or solely associated with increased HDL-C levels did not decrease the risk of myocardial infarction, shift the focus from HDL-C levels toward HDL functional properties. Indeed, HDL from atherosclerotic patients not only exhibit impaired atheroprotective functions but also acquire pro-atherogenic properties and are referred to as "dysfunctional" HDL; this occurs even in the presence of normal or elevated HDL-C levels. Pharmacological approaches aimed at restoring HDL functions may therefore impact more significantly on CVD outcome than drugs used so far to increase HDL-C levels. The aim of this review is to discuss the pathological conditions leading to the formation of dysfunctional HDL and their role in atherosclerosis and beyond.

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.

Long-Term Efficacy and Safety of Pemafibrate, a Novel Selective Peroxisome Proliferator-Activated Receptor-α Modulator (SPPARMα), in Dyslipidemic Patients with Renal Impairment

Pemafibrate (K-877) is a novel selective peroxisome proliferator-activated receptor-α modulator (SPPARMα) with a favorable benefit-risk balance. Previous clinical trials of pemafibrate used stringent exclusion criteria related to renal functions. Therefore, we investigated its safety and efficacy in a broader range of patients, including those with chronic kidney disease (CKD). In this multicenter, single-arm, open-label, phase III trial, 0.2⁻0.4 mg/day pemafibrate was administered for 52 weeks to 189 patients with hypertriglyceridemia and an estimated glomerular filtration rate (eGFR) ≥ 45 mL/min/1.73 m² on statin or regardless of eGFR when statin was not administered. Post-hoc analyses were performed on subgroups stratified by baseline eGFR. Triglyceride levels decreased by 45.9% at week 52 (last-observation-carried-forward). These reductions were not correlated with baseline eGFR. The eGFR < 30 mL/min/1.73 m² subgroup showed the greatest reduction in chylomicron, very low-density lipoprotein, small low-density lipoprotein cholesterol levels, and an increase in high-density lipoprotein cholesterol levels. The incidences of adverse events and adverse drug reactions were 82.0% and 31.7%, respectively, and these were not associated with baseline eGFR. In CKD patients, pemafibrate blood concentrations were not elevated. Pemafibrate showed a good safety profile and efficacy in correcting lipid abnormalities in a broad range of patients, including those with CKD.

Apolipoproteins A and B and PCSK9: Nontraditional Cardiovascular Risk Factors in Chronic Kidney Disease and in End-Stage Renal Disease

PURPOSE

Nontraditional cardiovascular risk factors as apolipoprotein A (ApoA), apolipoprotein B (ApoB), and the proprotein convertase subtilisin/kexin type 9 (PCSK9) increase the prevalence of cardiovascular mortality in chronic kidney disease (CKD) or in end-stage renal disease (ESRD) through quantitative alterations. This review is aimed at establishing the biomarker (ApoA, ApoB, and PCSK9) level variations in uremic patients, to identify the studies showing the association between these biomarkers and the development of cardiovascular events and to depict the therapeutic options to reduce cardiovascular risk in CKD and ESRD patients.

METHODS

We searched the electronic database of PubMed, Scopus, EBSCO, and Cochrane CENTRAL for studies evaluating apolipoproteins and PCSK9 in CKD and ESRD. Randomized controlled trials, observational studies (including case-control, prospective or retrospective cohort), and reviews/meta-analysis were included if reference was made to those keys and cardiovascular outcomes in CKD/ESRD.

RESULTS

18 studies met inclusion criteria. Serum ApoA-I has been significantly associated with the development of new cardiovascular event and with cardiovascular mortality in ESRD patients. ApoA-IV level was independently associated with maximum carotid intima-media thickness (cIMT) and was a predictor for sudden cardiac death. The ApoB/ApoA-I ratio represents a strong predictor for coronary artery calcifications, cardiovascular mortality, and myocardial infarction in CKD/ESRD. Plasma levels of PCSK9 were not associated with cardiovascular events in CKD patients.

CONCLUSIONS

Although the "dyslipidemic status" in CKD/ESRD is not clearly depicted, due to different research findings, ApoA-I, ApoA-IV, and ApoB/ApoA-I ratio could be predictors of cardiovascular risk. Serum PCSK9 levels were not associated with the cardiovascular events in patients with CKD/ESRD. Probably in the future, the treatment of dyslipidemia in CKD/ESRD will be aimed at discovering new effective therapies on the action of these biomarkers.

Malondialdehyde-modified LDL-related variables are associated with diabetic kidney disease in type 2 diabetes

BACKGROUND AND AIMS

Oxidized low-density lipoprotein (oxLDL) causes the development of atherosclerosis and kidney injury. Although circulating oxLDL levels were reportedly increased in type 2 diabetic patients with macroalbuminuria, it remains unclear whether albuminuria or the reduced glomerular filtration rate (GFR) is independently associated with the circulating oxLDL level. This study aimed to elucidate the association between the stage of diabetic nephropathy and serum malondialdehyde-modified LDL (MDA-LDL) and the ratio of MDA-LDL to LDL-cholesterol (MDA-LDL/LDL).

METHODS AND RESULTS

This retroactive cross-sectional study used data from 402 patients with type 2 diabetes. Patients undergoing hemodialysis were excluded. Serum MDA-LDL levels were significantly increased with increases in severity of albuminuria (103 ± 44 U/L, 109 ± 54 U/L, and 135 ± 72 U/L for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively; P for trend = 0.020) but not according to the estimated GFR (eGFR). An increased MDA-LDL/LDL ratio was significantly associated with both increased albuminuria (35 ± 13, 37 ± 14, and 40 ± 15 for normoalbuminuria, microalbuminuria, and macroalbuminuria, respectively; P for trend = 0.003) and reduced eGFR (34 ± 13, 36 ± 13, 38 ± 12, and 51 ± 28 for grade 1, 2, 3 and 4, respectively; P for trend = 0.002). Multiple linear regression analysis showed that neither the albumin excretion rate nor eGFR but ln-transformed triglycerides and LDL-C levels were independent determinants of both serum MDA-LDL levels and MDA-LDL/LDL ratios.

CONCLUSION

Serum MDA-LDL levels and MDA-LDL/LDL ratios were increased in those with dyslipidemia associated with diabetic kidney disease.

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.

Serum Non-High-Density Lipoprotein Cholesterol and Risk of Cardiovascular Disease in Community Dwellers with Chronic Kidney Disease: the Hisayama Study

AIM

It is not clear whether elevated serum non-high-density lipoprotein cholesterol (non-HDL-C) levels are a risk factor for cardiovascular disease (CVD) in subjects with chronic kidney disease (CKD) in the general population.

METHODS

A total of 2,630 community-dwelling Japanese subjects (1,107 men and 1,523 women) without history of CVD and aged ≥40 years were prospectively followed up for an average of 19 years, and the association between serum non-HDL-C levels and the incidence of type-specific CVD was estimated using a Cox proportional hazards model. CKD was defined as estimated glomerular filtration rate ＜60 mL/min/1.73 m2 or proteinuria (≥1＋ on dipstick).

RESULTS

At baseline, 357 subjects had CKD. During the follow up, 186 coronary heart disease (CHD) and 277 stroke events occurred. The age- and sex-adjusted incidence of CHD was significantly higher in subjects with higher non-HDL-C levels, both in those with and without CKD. In the CKD group, the risk of CHD was significantly higher in those with non-HDL-C levels of 150- 189 mg/dL [adjusted hazard ratio (HR), 2.23; 95% confidence interval (CI), 1.04-4.77] and those with levels ≥190 mg/dL (adjusted HR, 3.20; 95% CI, 1.46-7.03) than in those with levels ＜150 mg/dL. In the non-CKD group, the risk of CHD was significantly higher only in those with nonHDL-C levels ≥190 mg/dL (adjusted HR, 2.12; 95% CI, 1.33-3.38). However, no such association was observed for the risk of stroke.

CONCLUSIONS

Our findings suggest that higher serum non-HDL-C levels are associated with greater risk of CHD in subjects with and without CKD and that this association is greater in subjects with CKD than in those without CKD.

The pleiotropic vasoprotective functions of high density lipoproteins (HDL)

The pleiotropic functions of circulating high density lipoprotein (HDL) on peripheral vascular health are well established. HDL plays a pivotal role in reverse cholesterol transport and is also known to suppress inflammation, endothelial activation and apoptosis in peripheral vessels. Although not expressed in the central nervous system, HDL has nevertheless emerged as a potential resilience factor for dementia in multiple epidemiological studies. Animal model data specifically support a role for HDL in attenuating the accumulation of β-amyloid within cerebral vessels concomitant with reduced neuroinflammation and improved cognitive performance. As the vascular contributions to dementia are increasingly appreciated, this review seeks to summarize recent literature focused on the vasoprotective properties of HDL that may extend to cerebral vessels, discuss potential roles of HDL in dementia relative to brain-derived lipoproteins, identify gaps in current knowledge, and highlight new opportunities for research and discovery.

Associations among apolipoproteins, oxidized high-density lipoprotein and cardiovascular events in patients on hemodialysis

Apolipoproteins are associated with survival among patients on hemodialysis (HD), but these associations might be influenced by dysfunctional (oxidized) high-density lipoprotein (HDL). We assessed associations among apolipoproteins and oxidized HDL, mortality and cardiovascular disease (CVD) events in patients on HD. This prospective observational study examined 412 patients on prevalent HD. Blood samples were obtained before dialysis at baseline to measure lipids, apolipoproteins, oxidized LDL, oxidized HDL, high-sensitivity C-reactive protein (hs-CRP) and interleukin (IL)-6 at baseline, and HDL-C and hs-CRP were measured 12 months later. Patients were then prospectively followed-up (mean, 40 months) and all-cause mortality and composite CVD events were analyzed. Associations between variables at baseline and clinical outcome were assessed by Cox proportional hazards modeling (n = 412) and Cox hazards modeling with a time-varying covariate with HDL-C and hs-CRP (n = 369). Quartiles of apolipoproteins and oxidized HDL were not associated with all-cause mortality. However, Cox proportional hazards models with quartiles of each variable adjusted for confounders and hs-CRP or IL-6 identified apolipoprotein (apo)B-to-apoA-I ratio (apoB/apoA-I) and oxidized HDL, but not apoA-I or apoA-II, as independent risk factors for composite CVD events. These associations were confirmed by Cox proportional hazards modeling with time-varying covariates for hs-CRP. ApoB/apoA-I was independently associated with composite CVD events in 1-standard deviation (SD) increase-of-variables models adjusted for the confounders, oxidized HDL and hs-CRP. However, these associations disappeared from the model adjusted with IL-6 instead of hs-CRP, and oxidized HDL and IL-6 were independently associated with composite CVD events. Findings resembled those from Cox proportional hazards modeling using time-varying covariates with HDL-C adjusted with IL-6. In conclusion, both oxidized HDL and apoB/apoA-I might be associated with CVD events in patients on prevalent HD, while associations of apoB/apoA-I with CVD events differed between models of apoB/apoA-I quartiles and 1-SD increases, and were influenced by IL-6.

Impact of Renal Functional/Morphological Dynamics on the Calcification of Coronary and Abdominal Arteries in Patients with Chronic Kidney Disease

Aim: Fast-progressing vascular calcification (VC) is accompanied by renal atrophy and functional deterioration along with atherosclerosis in patients with chronic kidney disease (CKD). However, the relationship between VC progression and renal functional and/or morphological changes remains unclear.

Methods: We included 70 asymptomatic patients with CKD without hemodialysis in our study. To identify temporal variations, the coronary artery calcification score (CACS), abdominal aortic calcification index (ACI), and renal parenchymal volume index (RPVI) were determined via spiral computed tomography scans taken during the study. We investigated significant factors related to annualized variations of CACS (ΔCACS/y) and ACI (ΔACI/y).

Results: During the follow-up period (4.6 years), median values of CACS [in Agatston units (AU)] and ACI increased from 40.2 to 113.3 AU (p = 0.053) and from 13.2 to 21.7% (p = 0.036), respectively. Multivariate analysis revealed that CACS at baseline (p < 0.001) and diabetes mellitus (DM) status (p = 0.037) for ΔCACS/y and ACI at baseline (p = 0.017) and hypertension (HT) status (p = 0.046) for ΔACI/y were significant independent predictors. Furthermore, annualized RPVI variation was significantly related to both ΔCACS/y and ΔACI/y (R = −0.565, p < 0.001, and R = −0.289, p = 0.015, respectively). On the other hand, independent contributions of the estimated glomerular filtration rate (eGFR) and annualized eGFR variation to VC progression were not confirmed.

Conclusion: The degree of VC at baseline, DM, HT, and changes in renal volume, but not eGFR, had a strong impact on VC progression in patients with CKD.

Investigation of Metabolic Factors Associated with eGFR Decline Over 1 Year in a Japanese Population without CKD

Aim: Early intervention before the progression of chronic kidney disease (CKD) is essential to prevent end-stage renal disease (ESRD) and cardiovascular complications. This study evaluated the correlation between metabolic and lifestyle-related factors and the decline of estimated glomerular filtration rate (eGFR) over 1 year in a Japanese population without CKD.

Methods: Subjects who received two consecutive annual health checkups from 2013 to 2015 were involved. Factors associated with eGFR decline were identified using multiple regression models.

Results: A total of 2531 subjects aged 58.9 ± 11.7 years old were included in this study. Baseline levels of HDL-C and ApoA1 correlated with the eGFR decline over 1 year defined as eGFR reduction rate of 15% or more and/or eGFR at the next year < 60 ml/min/m² (odds ratio (OR) 0.87 (per 10 mg/dl); 95% CI, 0.80–0.94; p = 0.0012, 0.90 (per 10 mg/dl); 0.86–0.96; p = 0.0004, respectively). A U-shaped relationship between the eGFR decline and HDL-C or ApoA1 levels was not observed in non-CKD population of this study. Metabolic syndrome was significantly associated with eGFR decline (OR 1.32; 1.04–1.67; p = 0.0205), although obesity-related factors did not show a significant correlation with eGFR decline over 1 year.

Conclusion: Low HDL-C and ApoA1 levels significantly correlated with eGFR decline in a short period of 1 year. Metabolic syndrome also showed a significant association with eGFR decline. This study suggests the importance of hypertension and low HDL-C in the metabolic syndrome effect on eGFR decline rather than obesity in non-CKD population.

Association of High-Density Lipoprotein Subclasses with Chronic Kidney Disease Progression, Atherosclerosis, and Klotho

BACKGROUND

Atherosclerosis is often a complication of chronic kidney disease (CKD) because of dyslipidemia and CKD-mineral and bone disorder. High-density lipoproteins (HDLs) are grouped into various subclasses composed of multiple proteins and lipids, and their transformation is altered in CKD. We investigated the roles of lipoprotein subclasses in CKD progression, and atherosclerosis, and the relationships with Klotho and fibroblast growth factor (FGF) 23.

METHODS

Seventy-one CKD patients were enrolled in this prospective cohort study in Japan. The proportions of cholesterol level to total cholesterol level (cholesterol proportion) and lipoprotein particle numbers in 20 lipoprotein fractions were measured by a newly developed high-performance gel permeation chromatography.

RESULTS

Diabetic nephropathy was observed in 23.9% of the patients. The mean age was 75.0 years and estimated glomerular filtration rate (eGFR) was 17.2 ml/min./1.73m2. The lipoprotein particle numbers in small HDLs were higher in Stage 4 group than in Stage 5 group (p = 0.002). Multivariate regression analysis adjusted for baseline characteristics showed that the cholesterol proportions in very small HDLs were associated with eGFR change rate [F19 β = -17.63, p = 0.036] and ABI [F19 β = 0.047, p = 0.047] in Stage 4 group, and that serum soluble α-Klotho level was associated with the lipoprotein particle numbers in very small HDLs [F19 β = 0.00026, p = 0.012; F20 β = 0.00041, p = 0.036] in Stage 5 group.

CONCLUSIONS

This study showed that HDL subclasses are associated with CKD progression, ABI, and Klotho level in CKD-stage-specific manner.

Cardiothoracic Ratio as a Predictor of Cardiovascular Events in a Cohort of Hemodialysis Patients

AIM

The cardiothoracic ratio (CTR) on a chest X-ray is an indicator of cardiac enlargement, although its predictive power for cardiovascular disease (CVD) events in chronic kidney disease is unknown. We examined it in a cohort of hemodialysis patients, as compared with an N-terminal fragment of probrain natriuretic peptide (NT-proBNP).

METHOD

This was an observational study with cross-sectional and longitudinal analyses including 517 maintenance hemodialysis patients and 122 healthy control subjects. The main predictors were CTR and serum NT-proBNP, and the main outcome was CVD events in 5 years.

RESULTS

At baseline, the hemodialysis patients had higher median (interquartile range) levels of CTR [0.487 (0.457-0.520)] than the control group [0.458 (0.432-0.497)]. In the hemodialysis group, CTR was positively correlated with NT-proBNP (Spearman's r=0.44, P＜0.001). During follow-up, 190 CVD events occurred. CTR was significantly associated with the risk of CVD [HR 2.12 (95% CI, 1.38-3.25) for the fourth quartile as compared with the second quartile of CTR] in a multivariate Cox model. In the same model, NT-proBNP (fourth versus first quartile) showed a HR of 3.27 (2.02-5.31). When CTR and NT-proBNP were simultaneously included as predictors, only NT-proBNP remained a significant predictor of CVD events, all-cause mortality and composite of CVD plus all-cause mortality.

CONCLUSIONS

We showed that CTR was a significant and independent predictor of CVD in hemodialysis patients. CTR can be used for CVD risk stratification in hemodialysis patients when NT-proBNP is not available.

Subfractions of high-density lipoprotein (HDL) and dysfunctional HDL in chronic kidney disease patients

A number of studies have shown that chronic kidney disease (CKD) is associated with increased risk for cardiovascular disease (CVD). Chronic kidney disease is characterized by significant disturbances in lipoprotein metabolism, including differences in quantitative and qualitative content of high-density lipoprotein (HDL) particles. Recent studies have revealed that serum HDL cholesterol levels do not predict CVD in CKD patients; thus CKD-induced modifications in high-density lipoprotein (HDL) may be responsible for the increase in CV risk in CKD patients. Various methods are available to separate several subclasses of HDL and confirm their atheroprotective properties. However, under pathological conditions associated with inflammation and oxidation, HDL can progressively lose normal biological activities and be converted into dysfunctional HDL. In this review, we highlight the current state of knowledge on subfractions of HDL and HDL dysfunction in CKD.