Lipoprotein Metabolism and Lipid Management in Chronic Kidney Disease

Benefit of Ezetimibe Added to Simvastatin in Reduced Kidney Function

Efficacy of statin-based therapies in reducing cardiovascular mortality in individuals with CKD seems to diminish as eGFR declines. The strongest evidence supporting the cardiovascular benefit of statins in individuals with CKD was shown with ezetimibe plus simvastatin versus placebo. However, whether combination therapy or statin alone resulted in cardiovascular benefit is uncertain. Therefore, we estimated GFR in 18,015 individuals from the IMPROVE-IT (ezetimibe plus simvastatin versus simvastatin alone in individuals with cardiovascular disease and creatinine clearance >30 ml/min) and examined post hoc the relationship of eGFR with end points across treatment arms. For the primary end point of cardiovascular death, major coronary event, or nonfatal stroke, the relative risk reduction of combination therapy compared with monotherapy differed by eGFR (P=0.04). The difference in treatment effect was observed at eGFR≤75 ml/min per 1.73 m2 and most apparent at levels ≤60 ml/min per 1.73 m2 Compared with individuals receiving monotherapy, individuals receiving combination therapy with a baseline eGFR of 60 ml/min per 1.73 m2 experienced a 12% risk reduction (hazard ratio [HR], 0.88; 95% confidence interval [95% CI], 0.82 to 0.95); those with a baseline eGFR of 45 ml/min per 1.73 m2 had a 13% risk reduction (HR, 0.87; 95% CI, 0.78 to 0.98). In stabilized individuals within 10 days of acute coronary syndrome, combination therapy seemed to be more effective than monotherapy in individuals with moderately reduced eGFR (30-60 ml/min per 1.73 m2). Further studies examining potential benefits of combination lipid-lowering therapy in individuals with CKD are needed.

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.

Effects of statin therapy on clinical outcomes after acute myocardial infarction in patients with advanced renal dysfunction: A propensity score-matched analysis

Objective

Lipid lowering therapy is widely used for the prevention of cardiovascular complications after acute myocardial infarction (AMI). However, some studies show that this benefit is uncertain in patients with renal dysfunction, and the role of statins is based on the severity of renal dysfunction. In this study, we investigated the impact of statin therapy on major adverse cardiac events (MACEs) and all-cause mortality in patients with advanced renal dysfunction undergoing percutaneous coronary intervention (PCI) after AMI.

Methods

This study was based on the Korea Acute Myocardial Infarction Registry database. We included 861 patients with advanced renal dysfunction from among 33,205 patients who underwent PCI after AMI between November 2005 and July 2012. Patients were divided into two groups: a statin group (n = 537) and a no-statin group (n = 324). We investigated the 12-month MACEs (cardiac death, myocardial infarction, repeated PCI or coronary artery bypass grafting) and all-cause mortality of each group. Subsequently, a propensity score-matched analysis was performed.

Results

In the total population studied, no significant differences were observed between the two groups with respect to the rate of recurrent MI, repeated PCI, coronary artery bypass grafting (CABG), or all-cause mortality. However, the cardiac death rate was significantly lower in the statin group (p = 0.009). Propensity score-matched analysis yielded 274 pairs demonstrating, results similar to those obtained from the total population. However, there was no significant difference in the cardiac death rate in the propensity score-matched population (p = 0.103). Cox-regression analysis revealed only left ventricular ejection fraction to be an independent predictor of 12-month MACEs (Hazard ratio [HR] of 0.979, 95% confidence interval [CI], 0962–0.996, p = 0.018).

Conclusions

Statin therapy was not significantly associated with a reduction in the 12-month MACEs or all-cause mortality in patients with advanced renal dysfunction undergoing PCI after AMI.

High-density lipoprotein particle pattern and overall lipid responses to a short-term moderate-intensity aerobic exercise training intervention in patients with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is associated with abnormal lipid profiles and altered high-density lipoprotein (HDL) particle size patterns. Lower levels of the larger, cardioprotective HDL particles found in CKD may play a role in the increased risk for cardiovascular disease in these patients. The current study was designed to assess the effects of short-term moderate-intensity aerobic exercise training on the HDL particle pattern and overall lipid profiles in stage 3 CKD patients.

METHODS

Forty-six men and women with stage 3 CKD were randomized to either exercise (EX, n = 25) or control (CON, n = 21). Those in the EX group completed 16 weeks of supervised moderate-intensity aerobic exercise three times per week. Serum total cholesterol, HDL cholesterol (HDL-C), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), HDL particle size, estimated glomerular filtration rate (eGFR), body composition and peak oxygen uptake (VO2peak) were assessed at baseline and week 16.

RESULTS

The rate of compliance in the EX group was 97 ± 7.2%. No change was observed in eGFR over time in either group. There was an 8.2% improvement in VO2peak in the EX group (P = 0.05), while VO2peak decreased in the CON group. HDL-C, TGs, HDL particle size and body composition remained unchanged in both groups. A trend was found for lower total cholesterol (TC) (P = 0.051) and LDL-C (P = 0.07) in the CON group.

CONCLUSION

Our findings indicate that a short-term aerobic exercise training intervention in stage 3 CKD patients does not induce changes in HDL particle size or favorable lipid profile modifications.

2017 Position Paper of the Italian Society for Cardiovascular Prevention (SIPREC) for an Updated Clinical Management of Hypercholesterolemia and Cardiovascular Risk: Executive Document

The benefits achieved by implementing cardiovascular prevention strategies in terms of reduced incidence of atherosclerotic diseases and mortality are accepted, worldwide. In particular, the clinical management of hypercholesterolemia has a fundamental role for all preventive strategies, both in primary and secondary prevention, at each stage of cardiovascular risk. Since the net clinical benefit of lipid-lowering therapy largely depends on baseline individual cardiovascular risk profile, the assessment of individual risk is essential to establish type and intensity of both preventive and therapeutic strategies. Thus, the real challenge in a setting of clinical practice is not only to identify whom to treat among individuals at low-to-moderate risk, but mostly how much and how long to treat high or very-high risk patients. This manuscript, which reflects concepts and positions that have been published in a more extensive document of the Italian Society for Cardiovascular Prevention (SIPREC), deals with the diagnostic and therapeutic management of patients with dyslipidaemia, with an evidence-based approach adapted and updated from recent guidelines of the European Society of Cardiology and very recent results of randomized clinical trials. The purpose is to suggest a multidimensional and integrated actions aimed at eliminating or minimizing the impact of cardiovascular diseases and their related disabilities and mortality in patients with hypercholesterolemia.

ApoB and apoM - New aspects of lipoprotein biology in uremia-induced atherosclerosis

Chronic kidney disease affects as much as 13% of the population, and is associated with a markedly increased risk of developing cardiovascular disease. One of the underlying reasons is accelerated development of atherosclerosis. This can be ascribed both to increased occurrence of traditional cardiovascular risk factors, and to risk factors that may be unique to patients with chronic kidney disease. The latter is reflected in the observation that the current treatment modalities, mainly directed against traditional risk factors, are insufficient to prevent cardiovascular disease in the patient with chronic kidney disease. This review discusses mechanisms accelerating uremic atherosclerosis with a specific focus on the putative roles of apolipoprotein(apo)s B and M that may be particularly important in patients with chronic kidney disease.

Unusual Dyslipidemia in Patients with Chronic Kidney Diseases

INTRODUCTION

Chronic Kidney Disease (CKD) is a major and globally increasing health problem in the general population arising from a spectrum of diseases. Majority of the patients die even before reaching End Stage Renal Disease (ESRD) due to cardiovascular complications which arise due to altered lipoprotein compositions.

AIM

Present study was aimed at evaluating the serum lipid profile in CKD patients and to find the pattern of its alteration in both haemodialyzed and conservatively treated CKD patients.

MATERIALS AND METHODS

Seventy one randomly selected CKD patients attending a tertiary care hospital of Assam during one year of time frame (40 haemodialyzed and 31 conservatively treated) along with 50 apparently healthy controls were included in the study. Test for serum lipid profile, urea creatinine, FBS, PPBS, total protein and albumin were carried out in all the cases and controls. The results were analyzed and compared with the controls using Microsoft Excel software.

RESULTS

Triglyceride Level (TGL) of CKD group 157.88±61.82, controls 96.98±37.52, Very Low Density Lipoprotein (VLDL) of CKD group 31.58±12.36, controls 19.39±7.50 was marginally elevated and High Density Lipoprotein (HDL) of CKD group 33.40±9.06, controls 45.95±10.35 was significantly reduced in the patient group as compared to the controls and the results were statistically highly significant with p-value<0.001. Total cholesterol (CKD group 128.2±53.57, controls 142.53±31.44) and LDL (CKD group 63.23±46.47, controls 77.35±26.81) were lower in the patient group as compared to the controls, however the difference was statistically not significant (p value 0.09 and 0.059 respectively). There was no statistically significant difference of lipid profile between hemodialyzed and conservatively treated CKD groups and there was no gender related variation of lipid profile too.

CONCLUSION

Increased TGL and reduced HDL, rather than increased total cholesterol and increased LDL are responsible for the high incidence of cardiovascular complications in CKD patients. Hypolipidemic drugs and low fat diet may be helpful in impeding the progression of cardiovascular complications and decrease mortality and morbidity in those patients.

Live donor study - implications of kidney donation on cardiovascular risk with a focus on lipid parameters including lipoprotein a

In this prospective observational cohort study, we evaluate the change in cardiovascular risk parameters, with a focus on lipids, in live kidney donors 1 year post donation. Body mass index, systolic/diastolic blood pressure, kidney function (chromium-51 ethylenediaminetetraacetic acid estimated glomerular filtration) and lipid parameters were measured at baseline and 1 year. Data on 87 live kidney donors were collected. Body mass index increased from 26.5 ± 2.7 pre to 27.4 ± 3.0 kg/m(2) post donation (p < 0.0001). Chromium-51 ethylenediaminetetraacetic acid estimated glomerular filtration decreased from 111.8 ± 20.0 pre to 72.1 ± 13.1 mL/min/1.73 m(2) post donation (p < 0.0001). Serum triglyceride levels increased from 0.8 (interquartile range 0.6-1.3) pre to 1.0 mmol/L (interquartile range 0.7-1.6) post donation (p = 0.0004). Statin use increased from 11.5% pre to 21% post donation (p < 0.005). Low-density lipoprotein remained stable, and other lipids (high-density lipoprotein, apolipoprotein B and lipoprotein a) did not change post donation.

Dyslipidemia in patients with chronic kidney disease: etiology and management

Patients with chronic kidney disease (CKD), including those with end-stage renal disease, treated with dialysis, or renal transplant recipients have an increased risk for cardiovascular disease (CVD) morbidity and mortality. Dyslipidemia, often present in this patient population, is an important risk factor for CVD development. Specific quantitative and qualitative changes are seen at different stages of renal impairment and are associated with the degree of glomerular filtration rate declining. Patients with non-dialysis-dependent CKD have low high-density lipoproteins (HDL), normal or low total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol, increased triglycerides as well as increased apolipoprotein B (apoB), lipoprotein(a) (Lp (a)), intermediate- and very-low-density lipoprotein (IDL, VLDL; “remnant particles”), and small dense LDL particles. In patients with nephrotic syndrome lipid profile is more atherogenic with increased TC, LDL, and triglycerides. Lipid profile in hemodialysis (HD) patients is usually similar to that in non-dialysis-dependent CKD patients. Patients on peritoneal dialysis (PD) have more altered dyslipidemia compared to HD patients, which is more atherogenic in nature. These differences may be attributed to PD per se but may also be associated with the selection of dialytic modality. In renal transplant recipients, TC, LDL, VLDL, and triglycerides are elevated, whereas HDL is significantly reduced. Many factors can influence post-transplant dyslipidemia including immunosuppressive agents. This patient population is obviously at high risk; hence, prompt diagnosis and management are required to improve their clinical outcomes. Various studies have shown statins to be effective in the cardiovascular risk reduction in patients with mild-to-moderate CKD as well as in renal transplant recipients. However, according to recent clinical randomized controlled trials (4D, A Study to Evaluate the Use of Rosuvastatin in Subjects on Regular Dialysis: an Assessment of Survival and Cardiovascular Events, and Study of Heart and Renal protection), these beneficial effects are uncertain in dialyzed patients. Therefore, further research for the most suitable treatment options is needed.

Apolipoprotein L1 and apolipoprotein A-IV and their association with kidney function

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is a common disease with an estimated prevalence of 10-12%. There are pronounced differences between ethnicities with a 3-fold to 4-fold higher lifetime risk for end-stage kidney disease in African Americans compared to European Americans. The purpose of this review was to discuss recent findings on two apolipoproteins (apolipoprotein L1 and A-IV) in the context of kidney disease and kidney function.

RECENT FINDINGS

The observation that certain apolipoprotein L1 risk genotypes that are only present in African Americans might explain a major fraction of the ethnic differences for nondiabetic CKD has set the stage for this otherwise under-researched apolipoprotein. These risk genotypes on the one hand protect African Americans against African sleeping sickness but cause on the other hand several types of nondiabetic CKD. We are currently beginning to understand the mechanisms how apolipoprotein L1 is involved in the modification of lysosomal and cytoplasmic membranes. The second protein, apolipoprotein A-IV (apoA-IV), turned out to be an early marker of kidney impairment not only in patients with primary CKD but also in individuals from the general population. Genetic studies provided strong support of a causal effect of kidney function on apoA-IV concentrations.

SUMMARY

These two apolipoproteins have very distinct properties. Apolipoprotein L1 is causally involved in the development of nondiabetic CKD in African Americans. In contrast, apoA-IV is an early marker for kidney impairment.

PCSK9 in chronic kidney disease

PURPOSE

Chronic kidney disease (CKD) is accompanied by a number of secondary metabolic dysregulations, such as lipid abnormalities, presenting with unique characteristics. Proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitors have been introduced as the new era in the management of dyslipidemia with promising results in groups with refractory lipid abnormalities. Increasing number of studies investigate the possible association of PCSK9 levels with kidney function, especially with nephrotic range proteinuria, as well as its role as a prognostic cardiovascular risk marker in CKD. In this review, we discuss the existing evidence for PCSK9 levels in patient groups with nephrotic syndrome, non-dialysis CKD, end-stage renal disease and kidney transplantation.

METHODS

Online research was conducted in MEDLINE database to identify articles investigating PCSK9 in all different aspects of CKD. References from relevant studies were screened for supplementary articles.

RESULTS

Four cross-sectional studies, one secondary analysis, one publication from two independent cohort studies and one multicentre prospective cohort study assessed PCSK9 plasma levels in different subgroups of CKD patients. PCSK9 levels increase in nephrotic syndrome and have a positive correlation with proteinuria. In CKD patients, no correlation was found between PCSK9 levels and estimated GFR. Peritoneal dialysis patients have higher PCSK9 levels compared with hemodialysis and renal transplant patients as well as general population.

CONCLUSION

Accumulative evidence focuses on the possible association of PCSK9 levels with kidney function. No data are available for the administration of PCSK9 inhibitors in CKD patients. Further research will optimize knowledge on the role of PCSK9 levels and PCSK9 inhibitors in CKD.

Risk factors of progressive IgA nephropathy which progress to end stage renal disease within ten years: a case-control study

Background

There were few related studies aiming to severe IgA nephropathy (IgAN) which could progress rapidly to end stage renal disease (ESRD) within ten years. To find valuable clinical or pathological factors and promising precautions is essential.

Methods

A single center case–control study was performed. Fifty ESRD patients with the primary cause of IgAN and a short renal survival time of less than ten years after diagnose were enrolled in the case group. One hundred IgAN patients with a renal survival time of more than ten years were enrolled in the control group. IgA Oxford classification scores, clinical data at baseline and during the follow-up were collected. Multivariate logistic regression was used to investigate factors associated with the development of ESRD.

Results

There were significant differences in baseline clinical data between these two groups, as well as the constituent ratio of Oxford MEST-score. Distinct differences were observed in time-average uric acid(TA-UA), time-average hemoglobin(TA-Hb), time-average albumin(TA-Alb), time-average total cholesterol(TA-TC) and time-average urinary protein(TA-P) during the follow-up. In multivariate logistic models, IgA Oxford score M1(OR = 5.10, P = 0.018) and eGFR(OR = 0.97, P = 0.039) at biopsy, TA-UA (OR = 2.06, P = 0.026) and TA-Hb (OR = 0.53, P = 0.022) during the follow-up were identified independent factors for developing ESRD.

Conclusion

IgAN patients with pathological assessment of M1, low baseline eGFR, TA-Hb and high TA-UA were more likely to progress to ESRD, and should be paid more attention. Appropriate regulations of UA, Hb and urine protein after diagnose may be a promising treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0429-x) contains supplementary material, which is available to authorized users.

A Robust Lipidomics Workflow for Mammalian Cells, Plasma, and Tissue Using Liquid-Chromatography High-Resolution Tandem Mass Spectrometry

Lipids have been analyzed in applications including drug discovery, disease etiology elucidation, and natural products. The chemical and structural diversity of lipids requires a tailored lipidomics workflow for each sample type. Therefore, every protocol in the lipidomics workflow, especially those involving sample preparation, should be optimized to avoid the introduction of bias. The coupling of ultra-high-performance liquid chromatography (UHPLC) with high-resolution mass spectrometry (HRMS) allows for the separation and identification of lipids based on class and fatty acid acyl chain. This work provides a comprehensive untargeted lipidomics workflow that was optimized for various sample types (mammalian cells, plasma, and tissue) to balance extensive lipid coverage and specificity with high sample throughput. For identification purposes, both data-dependent and data-independent tandem mass spectrometric approaches were incorporated, providing more extensive lipid coverage. Popular open-source feature detection, data processing, and identification software are also outlined.

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.

[Chronic kidney disease and dyslipidaemia]

Chronic kidney disease (CKD) has to be considered as a high, or even very high risk cardiovascular risk condition, since it leads to an increase in cardiovascular mortality that continues to increase as the disease progresses. An early diagnosis of CKD is required, together with an adequate identification of the risk factors, in order to slow down its progression to more severe states, prevent complications, and to delay, whenever possible, the need for renal replacement therapy. Dyslipidaemia is a factor of the progression of CKD that increases the risk in developing atherosclerosis and its complications. Its proper control contributes to reducing the elevated cardiovascular morbidity and mortality presented by these patients. In this review, an assessment is made of the lipid-lowering therapeutic measures required to achieve to recommended objectives, by adjusting the treatment to the progression of the disease and to the characteristics of the patient. In CKD, it seems that an early and intensive intervention of the dyslipidaemia is a priority before there is a significant decrease in kidney function. Treatment with statins has been shown to be safe and effective in decreasing LDL-Cholesterol, and in the reduction of cardiovascular events in individuals with CKD, or after renal transplant, although there is less evidence in the case of dialysed patients.

Cytokine-like Activity of Liver Type Fatty Acid Binding Protein (L-FABP) Inducing Inflammatory Cytokine Interleukin-6

It has been reported that fatty acid binding proteins (FABPs) do not act only as intracellular mediators of lipid responses but also have extracellular functions. This study aimed to investigate whether extracellular liver type (L)-FABP has a biological activity and to determined serum L-FABP levels in patients with end-stage renal disease (ESRD). We isolated L-FABP complementary deoxyribonucleic acid (cDNA) from the Huh7 human hepatocarcinoma cell line and expressed the recombinant L-FABP protein in Escherichia coli. A549 lung carcinoma and THP-1 monocytic cells were stimulated with the human recombinant L-FABP. Human whole blood cells were also treated with the human recombinant L-FABP or interleukin (IL)-1α. IL-6 levels were measured in cell culture supernatants using IL-6 enzyme-linked immunosorbent assay (ELISA). Human recombinant L-FABP induced IL-6 in a dose-dependent manner in A549, THP-1 cells, and whole blood cells. The blood samples of healthy volunteers and patients with ESRD were taken after an overnight fast. The serum levels of L-FABP in healthy volunteers and ESRD patients were quantified with L-FABP ELISA. The values of L-FABP in patients with ESRD were significantly lower than those in the control group. Our results demonstrated the biological activity of L-FABP in human cells suggesting L-FABP can be a mediator of inflammation.

[LDL-cholesterol and cardiovascular events: the lower the better?]

For over 30 years, intensive research efforts investigated the role of LDL cholesterol in the pathogenesis of cardiovascular disease. In various settings, large statin trials showed an association between LDL cholesterol levels and cardiovascular event rates. This association is often referred to as the 'LDL cholesterol hypothesis'. More recent trials on agents with totally different modes of action confirmed this association and indicated a causal relationship between lower LDL cholesterol levels and improved cardiovascular outcomes. It has been proposed to term this causal relationship the 'LDL cholesterol principle'. It is to be expected that currently ongoing outcomes trials will further support the assumption of a causal relationship and will finally offer an armamentarium to therapists that will enable individualized treatment of dyslipidemias and their sequelae.

Impact of renal function on the effects of LDL cholesterol lowering with statin-based regimens: a meta-analysis of individual participant data from 28 randomised trials

BACKGROUND

Statin therapy is effective for the prevention of coronary heart disease and stroke in patients with mild-to-moderate chronic kidney disease, but its effects in individuals with more advanced disease, particularly those undergoing dialysis, are uncertain.

METHODS

We did a meta-analysis of individual participant data from 28 trials (n=183 419), examining effects of statin-based therapy on major vascular events (major coronary event [non-fatal myocardial infarction or coronary death], stroke, or coronary revascularisation) and cause-specific mortality. Participants were subdivided into categories of estimated glomerular filtration rate (eGFR) at baseline. Treatment effects were estimated with rate ratio (RR) per mmol/L reduction in LDL cholesterol.

FINDINGS

Overall, statin-based therapy reduced the risk of a first major vascular event by 21% (RR 0·79, 95% CI 0·77-0·81; p<0·0001) per mmol/L reduction in LDL cholesterol. Smaller relative effects on major vascular events were observed as eGFR declined (p=0·008 for trend; RR 0·78, 99% CI 0·75-0·82 for eGFR ≥60 mL/min per 1·73 m(2); 0·76, 0·70-0·81 for eGFR 45 to <60 mL/min per 1·73 m(2); 0·85, 0·75-0·96 for eGFR 30 to <45 mL/min per 1·73 m(2); 0·85, 0·71-1·02 for eGFR <30 mL/min per 1·73 m(2) and not on dialysis; and 0·94, 0·79-1·11 for patients on dialysis). Analogous trends by baseline renal function were seen for major coronary events (p=0·01 for trend) and vascular mortality (p=0·03 for trend), but there was no significant trend for coronary revascularisation (p=0·90). Reducing LDL cholesterol with statin-based therapy had no effect on non-vascular mortality, irrespective of eGFR.

INTERPRETATION

Even after allowing for the smaller reductions in LDL cholesterol achieved by patients with more advanced chronic kidney disease, and for differences in outcome definitions between dialysis trials, the relative reductions in major vascular events observed with statin-based treatment became smaller as eGFR declined, with little evidence of benefit in patients on dialysis. In patients with chronic kidney disease, statin-based regimens should be chosen to maximise the absolute reduction in LDL cholesterol to achieve the largest treatment benefits.

FUNDING

UK Medical Research Council, British Heart Foundation, Cancer Research UK, European Community Biomed Programme, Australian National Health and Medical Research Council, Australian National Heart Foundation.

Imbalance of plasma amino acids, metabolites and lipids in patients with lysinuric protein intolerance (LPI)

BACKGROUND

Lysinuric protein intolerance (LPI [MIM 222700]) is an aminoaciduria with defective transport of cationic amino acids in epithelial cells in the small intestine and proximal kidney tubules due to mutations in the SLC7A7 gene. LPI is characterized by protein malnutrition, failure to thrive and hyperammonemia. Many patients also suffer from combined hyperlipidemia and chronic kidney disease (CKD) with an unknown etiology.

METHODS

Here, we studied the plasma metabolomes of the Finnish LPI patients (n=26) and healthy control individuals (n=19) using a targeted platform for analysis of amino acids as well as two analytical platforms with comprehensive coverage of molecular lipids and polar metabolites.

RESULTS

Our results demonstrated that LPI patients have a dichotomy of amino acid profiles, with both decreased essential and increased non-essential amino acids. Altered levels of metabolites participating in pathways such as sugar, energy, amino acid and lipid metabolism were observed. Furthermore, of these metabolites, myo-inositol, threonic acid, 2,5-furandicarboxylic acid, galactaric acid, 4-hydroxyphenylacetic acid, indole-3-acetic acid and beta-aminoisobutyric acid associated significantly (P<0.001) with the CKD status. Lipid analysis showed reduced levels of phosphatidylcholines and elevated levels of triacylglycerols, of which long-chain triacylglycerols associated (P<0.01) with CKD.

CONCLUSIONS

This study revealed an amino acid imbalance affecting the basic cellular metabolism, disturbances in plasma lipid composition suggesting hepatic steatosis and fibrosis and novel metabolites correlating with CKD in LPI. In addition, the CKD-associated metabolite profile along with increased nitrite plasma levels suggests that LPI may be characterized by increased oxidative stress and apoptosis, altered microbial metabolism in the intestine and uremic toxicity.

Chronic Kidney Disease and Lipid Disorders

Introduction:

Chronic kidney disease (CKD) represents a serious public health problem due to the increase in incidence and prevalence of this disease worldwide. Given the significant morbidity and mortality from cardiovascular disease (CVD) in the population of patients with CKD, and the fact that dyslipidemia itself is a risk factor for CVD, increases the importance of lipid metabolism study in patients with CKD. Goal: Evaluate the lipid status of patients with chronic kidney disease.

Material and methods:

A one-year prospective study included 150 adult patients who were in various stages of chronic renal failure (stage I to IV). Estimate of creatinine clearance was performed using Cockroft-Goult formula. The classification of patients according to stages of chronic renal insufficiency was performed in accordance with the criteria of Kidney Disease Outcomes Quality Initiative (K/DOQI).

Results:

Of the total number of patients (N=150) there was 71 males and 79 females. The mean age of patients was 55.43 years. Average values of serum cholesterol were highest in patients with stage II renal disease and the lowest in patients classified as stage IV (5.76±1.60 mmol/L vs. 5.07±1.88 mmol/L). Analysis of the average value of triglycerides in blood show a slight increase through the stages of CKD in a manner that patients classified into stage I have low serum triglyceride levels (1.73±1.17 mmol/L (range 0.61 to 5.5 mmol/L), and patients classified in stage III the highest value 2.13±1.11 mmol/L (range 0.62 to 4.66 mmol/L).

Conclusion:

Average cholesterol levels does not statistically significantly change with progression of chronic renal disease. There is an almost linear increase in average triglyceride levels in chronic renal disease. Triglyceride levels in serum begins to increase in the early stage of chronic renal disease and reach the peak in stage IV.

Remnant lipoproteinemia predicts cardiovascular events in patients with type 2 diabetes and chronic kidney disease

BACKGROUND

Patients having type 2 diabetes mellitus (DM) and chronic kidney disease (CKD) are at high risk of cardiovascular events. Triglyceride-rich lipoprotein levels are synergistically increased in patients with DM and CKD. This study examined the predictive value of remnant lipoprotein levels for cardiovascular events in patients with DM and CKD.

METHODS

Three hundred and sixty-five patients with type 2 DM and CKD were enrolled. Serum levels of remnant lipoproteins (remnant-like lipoprotein particles cholesterol; RLP-C) were measured by an immunoseparation method. All patients were followed prospectively for a period of 45±23 months or until occurrence of one of the following events: cardiac death, non-fatal myocardial infarction, unstable angina requiring unplanned coronary revascularization, or ischemic stroke.

RESULTS

During the follow-up period, 59 patients had cardiovascular events. Multivariate Cox analysis revealed that high levels of RLP-C (≥4.3mg/dL; median value) were a significant risk factor for cardiovascular events, independent of traditional risk factors (HR: 1.30; 95% CI: 1.04-1.63; p=0.02). The addition of high levels of RLP-C to traditional risk factors improved net reclassification improvement (NRI) and integrated discrimination improvement (IDI) (NRI 0.36, p=0.01; and IDI 0.03, p=0.02).

CONCLUSIONS

RLP-C is useful for risk assessment of future cardiovascular events in patients having type 2 DM and CKD.

Red blood cell abnormalities and the pathogenesis of anemia in end-stage renal disease

Anemia is the most common hematologic complication in end-stage renal disease (ESRD). It is ascribed to decreased erythropoietin production, shortened red blood cell (RBC) lifespan, and inflammation. Uremic toxins severely affect RBC lifespan; however, the implicated molecular pathways are poorly understood. Moreover, current management of anemia in ESRD is controversial due to the "anemia paradox" phenomenon, which underlines the need for a more individualized approach to therapy. RBCs imprint the adverse effects of uremic, inflammatory, and oxidative stresses in a context of structural and functional deterioration that is associated with RBC removal signaling and morbidity risk. RBCs circulate in hostile plasma by raising elegant homeostatic defenses. Variability in primary defect, co-morbidity, and therapeutic approaches add complexity to the pathophysiological background of the anemic ESRD patient. Several blood components have been suggested as biomarkers of anemia-related morbidity and mortality risk in ESRD. However, a holistic view of blood cell and plasma modifications through integrated omics approaches and high-throughput studies might assist the development of new diagnostic tests and therapies that will target the underlying pathophysiologic processes of ESRD anemia.

Kidney Function as a Determinant of HDL and Triglyceride Concentrations in the Australian Population

Background: Chronic kidney disease (CKD) is a potent risk factor for cardiovascular disease (CVD). CVD risk increases in a stepwise manner with increasing kidney impairment and is significantly reduced by kidney transplantation, suggesting a causal relationship. Dyslipidemia, a well recognised CVD risk factor, is highly prevalent in CKD. While dyslipidemia is a risk factor for CKD, kidney impairment can also induce a dyslipidemic state that may contribute to the excess burden of CVD in CKD. We utilised a multipronged approach to determine whether a causal relationship exists. Materials and Methods: Retrospective case-control analysis of 816 patients admitted to the Royal Hobart Hospital in 2008–2009 with different degrees of kidney impairment and retrospective before-after cohort analysis of 60 patients who received a transplanted kidney between 1999 and 2009. Results: Decreased estimated GFR (eGFR) was independently associated with decreased high density lipoprotein (HDL, p < 0.0001) and increased triglyceride concentrations (p < 0.01) in multivariate analysis. There was no significant relationship between eGFR and low density lipoprotein (LDL) or total cholesterol in multivariate analysis. Kidney transplantation increased HDL (p < 0.0001) and decreased triglyceride (p = 0.007) concentration, whereas there was no significant change in LDL and total cholesterol. These effects were dependent on maintenance of graft function, statin therapy (those who were on) if graft failure occurred then HDL again decreased and triglycerides increased. Conclusions: Kidney transplantation ameliorated alterations in plasma lipoprotein profile associated with kidney impairment, an effect that was dependent on the maintenance of graft function. These data suggest that kidney function is a determinant of HDL and triglyceride concentrations in patients with CKD.

Etiology and management of dyslipidemia in children with chronic kidney disease and end-stage renal disease

Lipids are essential components of cell membranes, contributing to cell fuel, myelin formation, subcellular organelle function, and steroid hormone synthesis. Children with chronic kidney disease (CKD) and end-stage renal disease (ESRD) exhibit various co-morbidities, including dyslipidemia. The prevalence of dyslipidemias in children with CKD and ESRD is high, being present in 39-65% of patients. Elevated lipid levels in children without renal disease are a risk factor for cardiovascular disease (CVD), while the risk for CVD in pediatric CKD/ESRD is unclear. The pathogenesis of dyslipidemia in CKD features various factors, including increased levels of triglycerides, triglyceride-rich lipoproteins, apolipoprotein C3 (ApoC-III), decreased levels of cholesterylester transfer protein and high-density lipoproteins, and aberrations in serum very low-density and intermediate-density lipoproteins. If initial risk assessment indicates that a child with advanced CKD has 2 or more co-morbidities for CVD, first-line treatment should consist of non-pharmacologic management such as therapeutic lifestyle changes and dietary counseling. Pharmacologic treatment of dyslipidemia may reduce the incidence of CVD in children with CKD/ESRD, but randomized trials are lacking. Statins are the only class of lipid-lowering drugs currently approved by the U.S. Food and Drug Administration (FDA) for use in the pediatric population. FDA-approved pediatric labeling for these drugs is based on results from placebo-controlled trial results, showing 30-50% reductions in baseline low-density lipoprotein cholesterol. Although statins are generally well tolerated in adults, a spectrum of adverse events has been reported with their use in both the clinical trial and post-marketing settings.

High-Performance Affinity Chromatography: Applications in Drug-Protein Binding Studies and Personalized Medicine

The binding of drugs with proteins and other agents in serum is of interest in personalized medicine because this process can affect the dosage and action of drugs. The extent of this binding may also vary with a given disease state. These interactions may involve serum proteins, such as human serum albumin or α1-acid glycoprotein, or other agents, such as lipoproteins. High-performance affinity chromatography (HPAC) is a tool that has received increasing interest as a means for studying these interactions. This review discusses the general principles of HPAC and the various approaches that have been used in this technique to examine drug-protein binding and in work related to personalized medicine. These approaches include frontal analysis and zonal elution, as well as peak decay analysis, ultrafast affinity extraction, and chromatographic immunoassays. The operation of each method is described and examples of applications for these techniques are provided. The type of information that can be obtained by these methods is also discussed, as related to the analysis of drug-protein binding and the study of clinical or pharmaceutical samples.

Endogenously elevated bilirubin modulates kidney function and protects from circulating oxidative stress in a rat model of adenine-induced kidney failure

Mildly elevated bilirubin is associated with a reduction in the presence and progression of chronic kidney disease and related mortality, which may be attributed to bilirubin's antioxidant properties. This study investigated whether endogenously elevated bilirubin would protect against adenine-induced kidney damage in male hyperbilirubinaemic Gunn rats and littermate controls. Animals were orally administered adenine or methylcellulose solvent (vehicle) daily for 10 days and were then monitored for 28 days. Serum and urine were assessed throughout the protocol for parameters of kidney function and antioxidant/oxidative stress status and kidneys were harvested for histological examination upon completion of the study. Adenine-treated animals experienced weight-loss, polyuria and polydipsia; however, these effects were significantly attenuated in adenine-treated Gunn rats. No difference in the presence of dihydroadenine crystals, lymphocytic infiltration and fibrosis were noted in Gunn rat kidneys versus controls. However, plasma protein carbonyl and F2-isoprostane concentrations were significantly decreased in Gunn rats versus controls, with no change in urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine or kidney tissue F2-isoprostane concentrations. These data indicated that endogenously elevated bilirubin specifically protects from systemic oxidative stress in the vascular compartment. These data may help to clarify the protective relationship between bilirubin, kidney function and cardiovascular mortality in clinical investigations.

Risk of New-Onset Dyslipidemia After Laparoscopic Adrenalectomy in Patients with Primary Aldosteronism

BACKGROUND

Many patients with primary aldosteronism (PA) show a significant decline in kidney function after adrenalectomy. Thus, PA patients who undergo surgery are at greater risk of both postoperative renal damage and new-onset metabolic events associated with renal insufficiency. The aim of this study was to explore postoperative changes in serum lipid levels and to identify risk factors associated with postoperative new-onset dyslipidemia in PA patients.

METHODS

The records of 57 Japanese patients who underwent unilateral laparoscopic adrenalectomy for PA were retrospectively surveyed. Clinical and biochemical data were evaluated at baseline and 12 months after surgery. Preoperative and postoperative estimated glomerular filtration (eGFR) and serum lipid profile, including triglycerides, high-density lipoprotein (HDL)-cholesterol and low-density lipoprotein (LDL)-cholesterol levels, were compared. Furthermore, uni- and multivariate analyses were performed to determine the predictors for postoperative new-onset dyslipidemia.

RESULTS

A significant decrease in eGFR and deterioration of serum lipid levels was identified postoperatively in most patients. Of the 39 patients without pre-existing dyslipidemia, 18 developed new-onset dyslipidemia postoperatively. Multivariate analysis identified preoperative lower eGFR and higher body mass index as independent predictors for new-onset dyslipidemia after surgery. On univariate analyses, additional factors associated with new-onset dyslipidemia included older age, male sex, higher LDL-cholesterol, and higher LDL/HDL ratio.

CONCLUSIONS

PA patients had a higher risk of postoperative new-onset or progressive dyslipidemia. Clinicians should pay attention to not only follow-up of renal impairment but also total management of new-onset metabolic events associated with renal insufficiency in PA patients.

Effect of colestilan on serum phosphorus in dialysis patients: A meta-analysis of the literature

AIM

To evaluate the efficacy and safety of colestilan as a phosphorus binder in dialysis patients, we performed a meta-analysis of randomized controlled trials.

METHODS

We retrieved studies that compared colestilan with placebo in the treatment of dialysis patients from Medline, EMBASE, the Cochrane Library and conference proceedings.

RESULTS

Four studies were included. The treatment durations ranged from 2 to 12 weeks, median 7.5 weeks. Compared with placebo group, colestilan significantly decreased serum phosphorus (WMD, -0.22 mmol/L; 95% CI, -0.33 to -0.12, P < 0.0001), calcium phosphorus product (WMD, -0.70 mmol(2) /L(2) ; 95% CI, -1.06 to -0.35, P = 0.0001), intact PTH (WMD, -5.37 pmol/L; 95% CI, -8.38 to -2.36, P = 0.0005) and LDL cholesterol (WMD, -0.78 mmol/L; 95% CI, -0.85 to -0.71, P < 0.00001). There was no significant difference in serum calcium between the two groups. Colestilan therapy increased gastrointestinal complaints significantly (OR = 4.07, 95% CI: 3.06-6.53, P < 0.00001). Sensitivity analysis was performed by excluding studies with Jadad score of three or 3 g/day colestilan, the results did not change.

CONCLUSIONS

Short-term administration of colestilan is effective for the treatment of hyperphosphataemia in dialysis patients. Long-term effectiveness and safety needs to be evaluated.

Survival Benefit of Statins in Hemodialysis Patients Awaiting Renal Transplantation

End-stage renal disease (ESRD) patients have extraordinarily high cardiovascular risk and mortality, yet the benefit of statins in this population remains unclear based on the randomized trials. We investigated the prognostic value of statins in a large, pure cohort of prospectively recruited patients with ESRD awaiting renal transplantation, and being followed up in a dedicated cardiac clinic. We prospectively collected demographic, clinical, laboratory, and pharmacological data on 423 consecutive ESRD patients on hemodialysis awaiting renal transplantation. Survival analysis was performed as a function of statin therapy. The baseline characteristics were as follows: age 57 ± 11 years, males 64%, diabetes mellitus in 68%, known coronary artery disease in 30%, left ventricular (LV) ejection fraction 61 ± 11%. Over a mean follow-up of 2 years, there were 43 deaths. Adjusted for age, gender, hypertension, body mass index, diabetes mellitus, coronary artery disease, smoking, and treatment with angiotensin converting enzyme inhibitor, β blocker, and antiplatelet medications, statin use was a predictor of lower mortality (hazard ratio 0.30, 95% confidence interval 0.11-0.79, p = 0.01). This beneficial effect of statin was supported by propensity score analysis (p = 0.02) and was consistent across all clinical subgroups. The benefit of statins seemed to be greater in those with LV hypertrophy and smoking. Statin therapy in hemodialysis patients awaiting renal transplant is independently associated with better survival supporting its use in this high-risk population.

Associations of Trimethylamine N-Oxide With Nutritional and Inflammatory Biomarkers and Cardiovascular Outcomes in Patients New to Dialysis

OBJECTIVES

Trimethylamine N-oxide (TMAO) is a product of metabolism of phosphatidylcholine (lecithin) and carnitine by the intestinal microbiome. Elevated serum concentrations of TMAO have been linked to adverse cardiovascular outcomes in the general population. We examined correlates of serum TMAO and the relations among serum TMAO concentrations, all-cause mortality, and cardiovascular mortality and hospitalizations in a nationally derived cohort of patients new to hemodialysis (HD).

METHODS

We quantified serum TMAO by liquid chromatography and online tandem mass spectrometry and assessed nutritional and cardiovascular risk factors in 235 patients receiving HD and measured TMAO in pooled serum from healthy controls. We analyzed time to death and time to cardiovascular death or hospitalization using Cox proportional hazards regression.

RESULTS

Serum TMAO concentrations of patients undergoing HD (median, 43 μM/L; 25th-75th percentile, 28-67 μM/L) were elevated compared with those with normal or near-normal kidney function (1.41 ± 0.49 μM/L). TMAO was directly correlated with serum albumin (Spearman rank correlation, 0.24; 95% CI, 0.12-0.35; P <.001), prealbumin (Spearman rank correlation, 0.19; 95% CI, 0.07-0.31; P = .003), and creatinine (Spearman rank correlation, 0.21; 95% CI, 0.08-0.33; P = .002) and inversely correlated with log C-reactive protein (Spearman rank correlation, -0.18; 95% CI, -0.30 to -0.06; P = .005). Higher serum concentrations of TMAO were not significantly associated with time to death (Spearman rank correlation, 0.84; CI, 0.65-1.09; P = .19) or time to cardiovascular hospitalization or cardiovascular death (Spearman rank correlation, 0.88; CI, 0.57-1.35; P = .55).

CONCLUSIONS

Serum TMAO concentrations were markedly elevated and correlated directly with biochemical markers of nutritional status and inversely with markers of inflammation in patients receiving HD. There was no significant association between serum TMAO concentrations and all-cause mortality, cardiovascular death, or hospitalizations. In patients receiving dialysis-in contrast with the general population-adverse vascular effects of TMAO may be counterbalanced by associations with nutritional or inflammatory status.

The Effect of n-3 Fatty Acids on Small Dense Low-Density Lipoproteins in Patients With End-Stage Renal Disease: A Randomized Placebo-Controlled Intervention Study

OBJECTIVE

Patients with end-stage renal disease (ESRD) have a high risk of cardiovascular disease. Small dense low-density lipoprotein (sdLDL) particles are particularly atherogenic. Marine n-3 polyunsaturated fatty acids (PUFA) may have a beneficial effect on numbers of sdLDL particles, and the aim of this study was to investigate the effect of n-3 PUFA on plasma levels of sdLDL in patients with ESRD.

METHODS

ESRD patients with cardiovascular disease (n = 161) on chronic hemodialysis were randomized to treatment with 1.7 g of n-3 PUFA (n = 81) or 2 g of placebo (olive oil; n = 80) for 3 months. The study was double-blinded. Densities of LDL and percentages of sdLDL (sdLDL%) of total LDL were measured before and after intervention. On the basis of sdLDL%, patients were classified as having lipid pattern A, I (intermediate), or B defined by a successive increase in sdLDL concentration and decrease in lipid particle size.

RESULTS

n-3 PUFAs significantly reduced triglycerides. However, LDL cholesterol remained unchanged. In the n-3 group, the LDL density did not change significantly during follow-up. Similarly, the LDL density remained unchanged in the placebo group. In the n-3 group, the sdLDL% was 34% at baseline and unchanged at follow-up. At baseline 71% had LDL pattern A, 9% had pattern I, and 20% had pattern B, and none of these patterns were significantly changed by n-3 PUFA supplementation.

CONCLUSION

Dietary supplementation with 1.7 g of n-3 PUFA had no effect on LDL density or sdLDL levels in patients with ESRD.

Low-density lipoprotein receptor affects the fertility of female mice

Low-density lipoprotein receptor (LDLR) has been demonstrated to play a central role in lipoprotein metabolism, with Ldlr-deficient (Ldlr–/–) mice developing severe dyslipidemia. In the present study we investigated whether Ldlr knockout could harm female reproduction and explored the mechanisms involved. The results indicate that although the number of litters born to Ldlr–/– mice did not differ significantly from that born to controls, the number of pups per litter was significantly lower in the former group. Interestingly, although Ldlr–/– mice were obese, the weight of their ovaries was lower than that in control mice. Serum cholesterol levels was significantly higher in Ldlr–/– mice than in their wild-type counterparts. In contrast, there were significant decreases in cholesterol, triglyceride and total lipid levels in ovaries of Ldlr–/– mice. Both ovarian lipid deposition, as detected by Oil red O staining, and lipid droplets, as evaluated by transmission electron microscopy, supported decreased lipid levels in ovaries from Ldlr–/– mice. In addition, Ldlr–/– mice had fewer ovarian follicles, more atretic follicles, lower oestrogen levels and spent significantly less time in oestrus than did the controls. Superovulation assays indicated immature Ldlr–/– mice ovulated fewer ova than controls. These results indicate that lack of Ldlr results in dyslipidaemia and poor fertility.

In vivo studies of nanostructure-based photosensitizers for photodynamic cancer therapy

Animal models, particularly rodents, are major translational models for evaluating novel anticancer therapeutics. In this review, different types of nanostructure-based photosensitizers that have advanced into the in vivo evaluation stage for the photodynamic therapy (PDT) of cancer are described. This article focuses on the in vivo efficacies of the nanostructures as delivery agents and as energy transducers for photosensitizers in animal models. These materials are useful in overcoming solubility issues, lack of tumor specificity, and access to tumors deep in healthy tissue. At the end of this article, the opportunities made possible by these multiplexed nanostructure-based systems are summarized, as well as the considerable challenges associated with obtaining regulatory approval for such materials. The following questions are also addressed: (1) Is there a pressing demand for more nanoparticle materials? (2) What is the prognosis for regulatory approval of nanoparticles to be used in the clinic?

Quantification of HDL proteins, cardiac events, and mortality in patients with type 2 diabetes on hemodialysis

BACKGROUND AND OBJECTIVES

Impairment of HDL function has been associated with cardiovascular events in patients with kidney failure. The protein composition of HDLs is altered in these patients, presumably compromising the cardioprotective effects of HDLs. This post hoc study assessed the relation of distinct HDL-bound proteins with cardiovascular outcomes in a dialysis population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The concentrations of HDL-associated serum amyloid A (SAA) and surfactant protein B (SP-B) were measured in 1152 patients with type 2 diabetes mellitus on hemodialysis participating in The German Diabetes Dialysis Study who were randomly assigned to double-blind treatment of 20 mg atorvastatin daily or matching placebo. The association of SAA(HDL) and SP-B(HDL) with cardiovascular outcomes was assessed in multivariate regression models adjusted for known clinical risk factors.

RESULTS

High concentrations of SAA(HDL) were significantly and positively associated with the risk of cardiac events (hazard ratio per 1 SD higher, 1.09; 95% confidence interval, 1.01 to 1.19). High concentrations of SP-B(HDL) were significantly associated with all-cause mortality (hazard ratio per 1 SD higher, 1.10; 95% confidence interval, 1.02 to 1.19). Adjustment for HDL cholesterol did not affect these associations.

CONCLUSIONS

In patients with diabetes on hemodialysis, SAA(HDL) and SP-B(HDL) were related to cardiac events and all-cause mortality, respectively, and they were independent of HDL cholesterol. These findings indicate that a remodeling of the HDL proteome was associated with a higher risk for cardiovascular events and mortality in patients with ESRD.

Serum amyloid A and clusterin as potential predictive biomarkers for severe hand, foot and mouth disease by 2D-DIGE proteomics analysis

Hand, foot, and mouth disease (HFMD) affects more than one million children, is responsible for several hundred child deaths every year in China and is the cause of widespread concerns in society. Only a small fraction of HFMD cases will develop further into severe HFMD with neurologic complications. A timely and accurate diagnosis of severe HFMD is essential for assessing the risk of progression and planning the appropriate treatment. Human serum can reflect the physiological or pathological states, which is expected to be an excellent source of disease-specific biomarkers. In the present study, a comparative serological proteome analysis between severe HFMD patients and healthy controls was performed via a two-dimensional difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) strategy. Fifteen proteins were identified as differentially expressed in the sera of the severe HFMD patients compared with the controls. The identified proteins were classified into different groups according to their molecular functions, biological processes, protein classes and physiological pathways by bioinformatics analysis. The up-regulations of two identified proteins, serum amyloid A (SAA) and clusterin (CLU), were confirmed in the sera of the HFMD patients by ELISA assay. This study not only increases our background knowledge about and scientific insight into the mechanisms of HFMD, but also reveals novel potential biomarkers for the clinical diagnosis of severe HFMD.

Lipid mediators in diabetic nephropathy

The implications of lipid lowering drugs in the treatment of diabetic nephropathy have been considered. At the same time, the clinical efficacy of lipid lowering drugs has resulted in improvement in the cardiovascular functions of chronic kidney disease (CKD) patients with or without diabetes, but no remarkable improvement has been observed in the kidney outcome. Earlier lipid mediators have been shown to cause accumulative effects in diabetic nephropathy (DN). Here, we attempt to analyze the involvement of lipid mediators in DN. The hyperglycemia-induced overproduction of diacyglycerol (DAG) is one of the causes for the activation of protein kinase C (PKCs), which is responsible for the activation of pathways, including the production of VEGF, TGFβ1, PAI-1, NADPH oxidases, and NFҟB signaling, accelerating the development of DN. Additionally, current studies on the role of ceramide are one of the major fields of study in DN. Researchers have reported excessive ceramide formation in the pathobiological conditions of DN. There is less report on the effect of lipid lowering drugs on the reduction of PKC activation and ceramide synthesis. Regulating PKC activation and ceramide biosynthesis could be a protective measure in the therapeutic potential of DN. Lipid lowering drugs also upregulate anti-fibrotic microRNAs, which could hint at the effects of lipid lowering drugs in DN.

Effects of fish oil on serum lipid profile in dialysis patients: a systematic review and meta-analysis of randomized controlled trials

Background

The effects of fish oil supplements on lipid profile in dialysis patients are controversial. With increasing interest in the potential health benefits of fish oil, it is important to explore its real effects.

Objective

We aimed to identify and quantify the effects of fish oil on triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in dialysis patients.

Methods

PubMed, EMBASE and the Cochrane Central Register of Controlled Trials were searched for relevant trials of fish oil and lipid profile in dialysis patients. We identified 209 potential studies and included 13 randomized controlled trials. Eligible studies, determined by consensus using predefined criteria, were reviewed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and a meta-analysis was performed.

Results

Compared with the control group, serum TG and TC levels in the fish oil group were reduced by 0.23 mmol/L (95% CI, −0.31, −0.14, P <0.01) and 0.12 mmol/L (95% CI, −0.23, −0.01, P =0.03), respectively. HDL-C levels were increased by 0.20 mmol/L (95% CI, 0.01, 0.40, P <0.01) attributable to fish oil. In contrast, fish oil did not influence serum LDL-C levels. Subgroup analysis showed the effects of fish oil were stronger in subjects with higher baseline TG levels, and the long-term intervention (>12w) demonstrated a tendency towards greater improvement of serum HDL-C and LDL-C levels compared with short-term intervention (≤12 w). However, both of the changes were not statistically significant in meta-regression analysis. There were no obvious difference in effects of different doses and components of fish oil on lipid levels.

Conclusion

Fish oil supplements reduced serum TG and TC levels, and increased HDL-C levels, without affecting LDL-C levels among dialysis patients. It should benefit patients at risk of cardiovascular diseases. Based on randomized controlled trials, we suggested a daily supplement dose of fish oil for dialysis patients of >1 g, but a high dose might not be necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-511X-13-127) contains supplementary material, which is available to authorized users.

Chronic kidney disease, lipids and apolipoproteins, and coronary heart disease: the ARIC study

BACKGROUND

Chronic kidney disease (CKD) is associated with elevated apolipoprotein B to A-1 ratio (ApoB/A1). It is not known whether these markers are more strongly associated with the risk of coronary heart disease (CHD) in CKD compared to traditionally measured lipids and lipoprotein cholesterol ratios.

METHODS

We studied the association of lipids and apolipoproteins including non-HDL-cholesterol to HDL-cholesterol ratio (NonHDLc/HDLc) and ApoB/A1 with incident CHD in 10,137 individuals free of CHD at baseline (visit four) in the Atherosclerosis Risk in Communities (ARIC) study. An estimated glomerular filtration rate of 15 to <60 ml/min/1.73 m(2) based on a cystatin C measurement was used to define CKD (Stage 3-4). Cox proportional hazards regression models were used to determine the association of lipids and apolipoprotein measurements with the risk of CHD in those with and without CKD after adjustment for demographic and known clinical cardiovascular risk factors.

RESULTS

CKD was present in 1217 (12%) individuals free of CHD at baseline. The median follow-up time was 11.1 years. A CHD event developed in 498 out of 8920 individuals without CKD (incidence rate: 5.2 events per 1000 person-years) and in 138 out of 1217 individuals with CKD (incidence rate: 12.0 events per 1000 person-years; P < 0.001). Those with CKD had a lower concentration of ApoA1: median (in g/L) and interquartile range (IQR) = 1.40 (1.38-1.42) vs. 1.48 (1.47-1.49) P < 0.001; and a higher ApoB/A1 = 0.75 (0.73-0.77) vs. 0.71 (0.70-0.72) P < 0.001; than those without CKD (eGFR ≥ 60 ml/min/1.73 m(2)). Among individuals with CKD, ApoB/A1 and NonHDLc/HDLc were both associated with the risk of CHD: hazard ratios (HR) and 95% confidence intervals (CI) per one standard deviation increase = 1.22 (1.02-1.46) for ApoB/A1 and 1.30 (1.07-1.57) for NonHDLc/HDLc with no significant differences detected (P for interaction >0.1) when comparing these estimates to those of participants without CKD.

CONCLUSIONS

Although CKD is associated with a lower ApoA1 concentration and with a higher ApoB/A1, we found no evidence that these apolipoproteins are more strongly associated with CHD incidence in CKD compared to NonHDLc/HDLc.

Relationship between Icodextrin use and decreased level of small low-density lipoprotein cholesterol fractioned by high-performance gel permeation chromatography

Background

Because of the absorption of glucose in peritoneal dialysis (PD) solution, PD patients show an atherogenic lipid profile, which is predictive of poor survival in PD patients. Lipoprotein subclasses consist of a continuous spectrum of particles of different sizes and densities (fraction). In this study, we investigated the lipoprotein fractions in PD patients with controlled serum low-density lipoprotein (LDL) cholesterol level, and evaluated the effects of icodextrin on lipid metabolism.

Methods

Forty-nine PD patients were enrolled in this cross-sectional study in Japan. The proportions of cholesterol levels to total cholesterol level (cholesterol proportion) in 20 lipoprotein fractions were measured using an improved method of high-performance gel permeation chromatography (HPGPC).

Results

Twenty-six patients used icodextrin. Although no significant differences in cholesterol levels in LDL and high-density lipoprotein (HDL) were observed between the patients using icodextrin (icodextrin group) and control groups, HPGPC showed that the icodextrin group had significantly lower cholesterol proportions in the small LDL (t-test, p=0.053) and very small LDL (p=0.019), and significantly higher cholesterol proportions in the very large HDL and large HDL than the control group (p=0.037; p=0.066, respectively). Multivariate analysis adjusted for patient characteristics and statin use showed that icodextrin use was negatively associated with the cholesterol proportions in the small LDL (p=0.037) and very small LDL (p=0.026), and positively with those in the very large HDL (p=0.040), large HDL (p=0.047), and medium HDL (p=0.009).

Conclusions

HPGPC showed the relationship between icodextrin use and the cholesterol proportions in lipoprotein fractions in PD patients. These results suggest that icodextrin may improve atherogenic lipid profiles in a manner different from statin.

Causes and consequences of lipoprotein(a) abnormalities in kidney disease

Lipoprotein(a) is one of the strongest genetically determined risk factors for cardiovascular disease, and patients with chronic kidney disease have major disturbances in lipoprotein(a) metabolism. Concentrations are increased and are influenced by glomerular filtration rate (GFR) and the amount of proteinuria. The reason for this elevation can be increased synthesis, as is the case for patients with nephrotic syndrome or those treated by peritoneal dialysis. In hemodialysis patients, a catabolic block is the reason for this elevation. The elevated concentrations might contribute to the tremendous cardiovascular risk in this particular population. In particular, the genetically determined small apolipoprotein(a) isoforms are associated with an increased risk for cardiovascular events and total mortality.

The association of very-low-density lipoprotein with ankle-brachial index in peritoneal dialysis patients with controlled serum low-density lipoprotein cholesterol level

Background

Peripheral artery disease (PAD) represents atherosclerotic disease and is a risk factor for death in peritoneal dialysis (PD) patients, who tend to show an atherogenic lipid profile. In this study, we investigated the relationship between lipid profile and ankle-brachial index (ABI) as an index of atherosclerosis in PD patients with controlled serum low-density lipoprotein (LDL) cholesterol level.

Methods

Thirty-five PD patients, whose serum LDL cholesterol level was controlled at less than 120mg/dl, were enrolled in this cross-sectional study in Japan. The proportions of cholesterol level to total cholesterol level (cholesterol proportion) in 20 lipoprotein fractions and the mean size of lipoprotein particles were measured using an improved method, namely, high-performance gel permeation chromatography. Multivariate linear regression analysis was adjusted for diabetes mellitus and cardiovascular and/or cerebrovascular diseases.

Results

The mean (standard deviation) age was 61.6 (10.5) years; PD vintage, 38.5 (28.1) months; ABI, 1.07 (0.22). A low ABI (0.9 or lower) was observed in 7 patients (low-ABI group). The low-ABI group showed significantly higher cholesterol proportions in the chylomicron fraction and large very-low-density lipoproteins (VLDLs) (Fractions 3–5) than the high-ABI group (ABI>0.9). Adjusted multivariate linear regression analysis showed that ABI was negatively associated with serum VLDL cholesterol level (parameter estimate=-0.00566, p=0.0074); the cholesterol proportions in large VLDLs (Fraction 4, parameter estimate=-3.82, p=0.038; Fraction 5, parameter estimate=-3.62, p=0.0039) and medium VLDL (Fraction 6, parameter estimate=-3.25, p=0.014); and the size of VLDL particles (parameter estimate=-0.0352, p=0.032).

Conclusions

This study showed that the characteristics of VLDL particles were associated with ABI among PD patients. Lowering serum VLDL level may be an effective therapy against atherosclerosis in PD patients after the control of serum LDL cholesterol level.