Lipid and lipoprotein metabolism in chronic kidney disease

Fibrate and the risk of cardiovascular disease among moderate chronic kidney disease patients with primary hypertriglyceridemia

Introduction

Hypertriglyceridemia is the most prevalent dyslipidemia in patients with chronic kidney disease (CKD). However, research about fibrate treatment in CKD patients is limited, and assessing its benefits becomes challenging due to the frequent concurrent use of statins. Thus, this study is aimed to investigate the role of fibrate in CKD stage 3 patients with hypertriglyceridemia who did not receive other lipid-lowering agents.

Methods

This study enrolled patients newly diagnosed CKD3 with LDL-C<100mg/dL and had never received statin or other lipid-lowering agents from Chang Gung Research Database. The participants were categorized into 2 groups based on the use of fibrate: fibrate group and non-fibrate group (triglyceride >200mg/dL but not receiving fibrate treatment). The inverse probability of treatment weighting was performed to balance baseline characteristics.

Results

Compared with the non-fibrate group (n=2020), the fibrate group (n=705) exhibited significantly lower risks of major adverse cardiac and cerebrovascular events (MACCEs) (10.4% vs. 12.8%, hazard ratios [HRs]: 0.69, 95% confidence interval [CI]: 0.50 to 0.95), AMI (2.3% vs. 3.9%, HR: 0.52, 95% CI: 0.37 to 0.73), and ischemic stroke (6.3% vs. 8.0%, HR: 0.67, 95% CI: 0.52 to 0.85). The risk of all-cause mortality (5.1% vs. 4.5%, HR: 1.09, 95% CI: 0.67 to 1.79) and death from CV (2.8% vs. 2.3%, HR: 1.07, 95% CI: 0.29 to 2.33) did not significantly differ between the 2 groups.

Conclusion

This study suggests that, in moderate CKD patients with hypertriglyceridemia but LDL-C < 100mg/dL who did not take other lipid-lowering agents, fibrates may be beneficial in reducing cardiovascular events.

Can Concurrent Fibrate Use Reduce Cardiovascular Risks among Moderate Chronic Kidney Disease Patients Undergoing Statin Therapy? A Cohort Study

The role of fibrates in treating hypertriglyceridemia in chronic kidney disease (CKD) patients to prevent cardiovascular disease (CVD) has been insufficiently investigated. Since statin is considered the first-line treatment for dyslipidemia in CKD patients, this study aims to evaluate the role of concurrent fibrate therapy with statins among moderate CKD patients. We recruited CKD3 patients from the Chang Gung Research Database who were receiving statin treatment but had not previously been administered ezetimibe or niacin. The participants were divided into two groups based on their use of fibrates (fibrate group) or those with triglyceride levels >200 mg/dL without fibrate treatment (non-fibrate group). The fibrate group (n = 954) only exhibited a significantly lower incidence of AMI (4.4% vs. 5.4%, HR: 0.77, 95% CI: 0.61 to 0.98). The risk of major adverse cardiovascular and cerebrovascular events (14.7% vs. 15.6%, HR: 0.91, 95% CI: 0.72 to 1.15) and all-cause mortality (5.7% vs. 6.1%, HR: 0.91, 95% CI: 0.63 to 1.30) did not significantly differ between the fibrate group and the non-fibrate group (n = 2358). In moderate CKD patients, combining fibrate therapy with statins may not offer additional cardiovascular protection compared to statin alone.

Integrative phosphatidylcholine metabolism through phospholipase A2 in rats with chronic kidney disease

Dysregulation in lipid metabolism is the leading cause of chronic kidney disease (CKD) and also the important risk factors for high morbidity and mortality. Although lipid abnormalities were identified in CKD, integral metabolic pathways for specific individual lipid species remain to be clarified. We conducted ultra-high-performance liquid chromatography-high-definition mass spectrometry-based lipidomics and identified plasma lipid species and therapeutic effects of Rheum officinale in CKD rats. Adenine-induced CKD rats were administered Rheum officinale. Urine, blood and kidney tissues were collected for analyses. We showed that exogenous adenine consumption led to declining kidney function in rats. Compared with control rats, a panel of differential plasma lipid species in CKD rats was identified in both positive and negative ion modes. Among the 50 lipid species, phosphatidylcholine (PC), lysophosphatidylcholine (LysoPC) and lysophosphatidic acid (LysoPA) accounted for the largest number of identified metabolites. We revealed that six PCs had integral metabolic pathways, in which PC was hydrolysed into LysoPC, and then converted to LysoPA, which was associated with increased cytosolic phospholipase A2 protein expression in CKD rats. The lower levels of six PCs and their corresponding metabolites could discriminate CKD rats from control rats. Receiver operating characteristic curves showed that each individual lipid species had high values of area under curve, sensitivity and specificity. Administration of Rheum officinale significantly improved impaired kidney function and aberrant PC metabolism in CKD rats. Taken together, this study demonstrates that CKD leads to PC metabolism disorders and that the dysregulation of PC metabolism is involved in CKD pathology.

New Insights into Adiponectin and Leptin Roles in Chronic Kidney Disease

Chronic kidney disease (CKD) is commonly associated with a high burden of comorbidities and poor clinical outcomes. Malnutrition–inflammation–atherosclerosis syndrome is common in the more severe stages of CKD, suggesting a close interplay for these three comorbid conditions. Both malnutrition and obesity are associated with a disturbed adipokine profile and inflammation, contributing to a higher risk of cardiovascular disease (CVD) events. Adiponectin and leptin have important roles in carbohydrate and lipid metabolism, and in the inflammatory process. The effects of adiponectin and leptin alterations in CKD, which are usually increased, and their association with the different comorbidities found in CKD, will be focused on to understand their crosstalk with the risk of CVD events. Nonetheless, although adiponectin and leptin contribute to a higher risk of CVD events, further studies are warranted to fully clarify their roles, especially when different comorbidities exist.

Relationship between obesity-related parameters and chronic kidney disease in middle-aged and elderly populations in Taiwan: A community-based study

Globally, obesity is a major health problem and can markedly increase the risk of various diseases, including type 2 diabetes mellitus, hypertension (HTN), dyslipidemia, and chronic kidney disease (CKD). The association of obesity-related parameters, such as lipid parameters and their ratio, with CKD in clinical settings is not well understood. This study aimed to investigate the association of obesity-related parameters with CKD in the middle-aged and elderly population in Taiwan. This cross-sectional, community-based study recruited 400 participants (141 males and 259 females) aged 50 years or over from a community health promotion project at the Linkou Chang Gung Memorial Hospital (Guishan District, Taoyuan City) in 2014. Each participant completed a questionnaire including personal information and medical history during a face-to-face interview. Laboratory data were obtained from blood and urine sampling. The data were analyzed using t-test, chi-square test, Pearson's correlation test, multivariate logistic regression, and receiver operating characteristic (ROC) analysis. A total of 81 participants were identified as having CKD [estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m² or urine albumin/creatinine ratio ≥30 mg/g], and their mean triglyceride/high-density lipoprotein cholesterol (TG/HDL-C) ratio was 3.37 ± 2.72. The mean TG/HDL-C ratio of the 319 participants without CKD was 2.35 ± 1.66. After adjusting for age, TG/HDL-C was significantly positively correlated with blood pressure, body mass index, waist circumference, and fasting plasma glucose but not low-density lipoprotein cholesterol. There was a negative correlation between TG/HDL-C and eGFR. Multiple logistic regression model analysis showed that TG/HDL-C was still significantly associated with CKD (OR: 1.17, 95% CI: 1.01–1.36, p = 0.04) after adjusting for multiple covariates. The cut-off point of TG/HDL-C as a predictor of CKD was 2.54 with an area under the ROC curve of 0.61 (95% CI: 0.53–0.68). There was a significant positive correlation between TG/HDL-C and several cardiovascular disease risk factors, including obesity indices. The TG/HDL-C ratio was significantly associated with the risk of CKD and demonstrated predictive ability for CKD in the middle-aged and elderly population. Further studies on its application in clinical settings are warranted.

Non-High-Density Lipoprotein Cholesterol and Cardiovascular Outcomes in Chronic Kidney Disease: Results from KNOW-CKD Study

As non-high-density lipoprotein cholesterol (non-HDL-C) levels account for all atherogenic lipoproteins, serum non-HDL-C level has been suggested to be a marker for cardiovascular (CV) risk stratification. Therefore, to unveil the association of serum non-HDL-C levels with CV outcomes in patients with non-dialysis chronic kidney disease (ND-CKD), the patients at stages 1 to 5 (n = 2152) from the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD) were prospectively analyzed. The subjects were divided into quintiles by serum non-HDL-C level. The primary outcome was a composite of all-cause death or non-fatal CV events. The median duration of follow-up was 6.940 years. The analysis using the Cox proportional hazard model unveiled that the composite CV event was significantly increased in the 5th quintile (adjusted hazard ratio 2.162, 95% confidence interval 1.174 to 3.981), compared to that of the 3rd quintile. A fully adjusted cubic spline model depicted a non-linear, J-shaped association between non-HDL-C and the risk of a composite CV event. The association remained robust in a series of sensitivity analyses, including the analysis of a cause-specific hazard model. Subgroup analyses reveled that the association is not significantly altered by clinical conditions, including age, gender, body mass index, estimated glomerular filtration rate, and albuminuria. In conclusion, high serum non-HDL-C level increased the risk of adverse CV outcomes among the patients with ND-CKD. Further studies are warranted to define the optimal target range of non-HDL-C levels in this population.

The Roles of Fatty Acids and Apolipoproteins in the Kidneys

The kidneys are organs that require energy from the metabolism of fatty acids and glucose; several studies have shown that the kidneys are metabolically active tissues with an estimated energy requirement similar to that of the heart. The kidneys may regulate the normal and pathological function of circulating lipids in the body, and their glomerular filtration barrier prevents large molecules or large lipoprotein particles from being filtered into pre-urine. Given the permeable nature of the kidneys, renal lipid metabolism plays an important role in affecting the rest of the body and the kidneys. Lipid metabolism in the kidneys is important because of the exchange of free fatty acids and apolipoproteins from the peripheral circulation. Apolipoproteins have important roles in the transport and metabolism of lipids within the glomeruli and renal tubules. Indeed, evidence indicates that apolipoproteins have multiple functions in regulating lipid import, transport, synthesis, storage, oxidation and export, and they are important for normal physiological function. Apolipoproteins are also risk factors for several renal diseases; for example, apolipoprotein L polymorphisms induce kidney diseases. Furthermore, renal apolipoprotein gene expression is substantially regulated under various physiological and disease conditions. This review is aimed at describing recent clinical and basic studies on the major roles and functions of apolipoproteins in the kidneys.

Fenofibrate Delays the Need for Dialysis and Reduces Cardiovascular Risk Among Patients With Advanced CKD

CONTEXT

Fenofibrate provides limited cardiovascular (CV) benefits in the general population; however, little is known about its benefit among advanced chronic kidney disease (CKD) patients.

OBJECTIVE

This study compared outcomes among advanced CKD patients treated with fenofibrate, statins, a combination of both, and none of these.

METHODS

This national cohort study was based on Taiwan's National Health Insurance Research Database. Patients younger than 20 years with advanced CKD were identified and further divided into 4 groups according to treatment. The inverse probability of treatment weighting was used to balance baseline characteristics. Patients received fenofibrate, statins, a combination of fenofibrate and statins, or none of these in the 3 months preceding the advanced CKD date. Main outcome measures included all-cause mortality, CV death, and incidence of permanent dialysis.

RESULTS

The fenofibrate and statin groups exhibited a lower risk of CV death (fenofibrate vs nonuser: hazard ratio [HR]: 0.84; 95% CI, 0.75-0.94; statins vs nonuser: HR: 0.94; 95% CI, 0.90-0.97) compared with the nonuser group. The fenofibrate group further exhibited the lowest incidence of permanent dialysis (fenofibrate vs nonuser: subdistribution HR [SHR]: 0.78; 95% CI, 0.77-0.80; statins vs fenofibrate: SHR: 1.27; 95% CI, 1.26-1.29; combination vs fenofibrate: SHR: 1.15; 95% CI, 1.13-1.17). Furthermore, the combined administration of fenofibrate and high-intensity statins exhibited a lower risk of major adverse cardiac and cerebrovascular events.

CONCLUSION

For patients with advanced CKD, continuing fenofibrate may provide a protective effect on CV outcomes equal to that of statins, and it may further delay the need for permanent dialysis. The combination of fenofibrate and high-intensity statins may have additional benefits.

High-Density Lipoproteins and the Kidney

Dyslipidemia is a typical trait of patients with chronic kidney disease (CKD) and it is typically characterized by reduced high-density lipoprotein (HDL)-cholesterol(c) levels. The low HDL-c concentration is the only lipid alteration associated with the progression of renal disease in mild-to-moderate CKD patients. Plasma HDL levels are not only reduced but also characterized by alterations in composition and structure, which are responsible for the loss of atheroprotective functions, like the ability to promote cholesterol efflux from peripheral cells and antioxidant and anti-inflammatory proprieties. The interconnection between HDL and renal function is confirmed by the fact that genetic HDL defects can lead to kidney disease; in fact, mutations in apoA-I, apoE, apoL, and lecithin–cholesterol acyltransferase (LCAT) are associated with the development of renal damage. Genetic LCAT deficiency is the most emblematic case and represents a unique tool to evaluate the impact of alterations in the HDL system on the progression of renal disease. Lipid abnormalities detected in LCAT-deficient carriers mirror the ones observed in CKD patients, which indeed present an acquired LCAT deficiency. In this context, circulating LCAT levels predict CKD progression in individuals at early stages of renal dysfunction and in the general population. This review summarizes the main alterations of HDL in CKD, focusing on the latest update of acquired and genetic LCAT defects associated with the progression of renal disease.

Increased serum concentration of apolipoprotein B is associated with an increased risk of reaching renal replacement therapy in patients with diabetic kidney disease

Objective

Few studies have investigated the association of apolipoprotein B (ApoB) with the progression of diabetic kidney disease (DKD) and the risk of renal replacement therapy (RRT).

Method

In this retrospective cohort study, a group of 258 DKD patients with stage 3–5chronic kidney disease(CKD)were divided into low ApoB (<1.1 g/L) and high ApoB (≥1.1 g/L) groups and followed-up for 20.51 ± 6.11 months. The association of the serum ApoB concentration with RRT was determined by Kaplan–Meier and Cox regression analysis. ApoB was measured in the serum.

Results

Ninety-three of the 258 DKD patients needed RRT during follow-up. Kaplan–Meier analysis showed that patients with high ApoB were significantly more likely to progress to RRT than those with low ApoB (log-rank = 16.62, p < 0.001). The presence of high ApoB increased the risk of RRT. Analysis of ApoB as either a categorical (<1.1 g/L or ≥1.1 g/l) or continuous variable by univariate and multivariate regression found that ApoB was an independent risk factor of DKD progression to RRT in this group of DKD patients with stage 3–5 CKD (p < 0.05).

Conclusion

Increased ApoB was an independent predictor of progression to RRT. A larger study is needed to confirm the unfavorable prognosis of increased ApoB in DKD patients.

Current Understanding of the Relationship of HDL Composition, Structure and Function to Their Cardioprotective Properties in Chronic Kidney Disease

In the general population, the ability of high-density lipoproteins (HDLs) to promote cholesterol efflux is a predictor of cardiovascular events, independently of HDL cholesterol levels. Although patients with chronic kidney disease (CKD) have a high burden of cardiovascular morbidity and mortality, neither serum levels of HDL cholesterol, nor cholesterol efflux capacity associate with cardiovascular events. Important for the following discussion on the role of HDL in CKD is the notion that traditional atherosclerotic cardiovascular risk factors only partially account for this increased incidence of cardiovascular disease in CKD. As a potential explanation, across the spectrum of cardiovascular disease, the relative contribution of atherosclerotic cardiovascular disease becomes less important with advanced CKD. Impaired renal function directly affects the metabolism, composition and functionality of HDL particles. HDLs themselves are a heterogeneous population of particles with distinct sizes and protein composition, all of them affecting the functionality of HDL. Therefore, a more specific approach investigating the functional and compositional features of HDL subclasses might be a valuable strategy to decipher the potential link between HDL, cardiovascular disease and CKD. This review summarizes the current understanding of the relationship of HDL composition, metabolism and function to their cardio-protective properties in CKD, with a focus on CKD-induced changes in the HDL proteome and reverse cholesterol transport capacity. We also will highlight the gaps in the current knowledge regarding important aspects of HDL biology.

Treatment With Gemfibrozil Prevents the Progression of Chronic Kidney Disease in Obese Dahl Salt-Sensitive Rats

Recently, we reported that Dahl salt-sensitive leptin receptor mutant (SS^LepRmutant) rats exhibit dyslipidemia and renal lipid accumulation independent of hyperglycemia that progresses to chronic kidney disease (CKD). Therefore, in the current study, we examined the effects of gemfibrozil, a lipid-lowering drug (200 mg/kg/day, orally), on the progression of renal injury in SS and SS^LepRmutant rats for 4 weeks starting at 12 weeks of age. Plasma triglyceride levels were markedly elevated in the SS^LepRmutant strain compared to SS rats (1193 ± 243 and 98 ± 16 mg/day, respectively). Gemfibrozil treatment only reduced plasma triglycerides in the SS^LepRmutant strain (410 ± 79 mg/dL). MAP was significantly higher in the SS^LepRmutant strain vs. SS rats at the end of the study (198 ± 7 vs. 165 ± 7 mmHg, respectively). Administration of gemfibrozil only lowered MAP in SS^LepRmutant rats (163 ± 8 mmHg). During the course of the study, proteinuria increased to 125 ± 22 mg/day in SS rats. However, proteinuria did not change in the SS^LepRmutant strain and remained near baseline (693 ± 58 mg/day). Interestingly, treatment with gemfibrozil increased the progression of proteinuria by 77% in the SS^LepRmutant strain without affecting proteinuria in SS rats. The renal injury in the SS^LepRmutant strain progressed to CKD. Moreover, the kidneys from SS^LepRmutant rats displayed significant glomerular injury with mesangial expansion and increased renal lipid accumulation and fibrosis compared to SS rats. Treatment with gemfibrozil significantly reduced glomerular injury and lipid accumulation and improved renal function. These data indicate that reducing plasma triglyceride levels with gemfibrozil inhibits hypertension and CKD associated with obesity in SS^LepRmutant rats.

Serum apolipoprotein B/apolipoprotein A1 ratio is associated with the progression of diabetic kidney disease to renal replacement therapy

PURPOSE

The apolipoprotein B/apolipoprotein A1 (ApoB/ApoA1) ratio has been shown to be associated with cardiovascular disease risk and the progression of chronic kidney disease. The association between the ApoB/ApoA1 ratio and the progression of diabetic kidney disease (DKD) is not well studied.

METHODS

Patients with DKD were divided into four groups (< 0.63, ≥ 0.63 and < 0.85, ≥ 0.85 and < 1.15, ≥ 1.15) according to their ApoB/ApoA1 ratio. The association of the ApoB/ApoA1 ratio and progression of DKD to renal replacement therapy (RRT) were determined using Kaplan-Meier and Cox regression analyses.

RESULTS

The Kaplan-Meier analysis showed that the ≥ 1.15 group (log-rank = 15.771, P < 0.05) was significantly more likely to progress to RRT than the other three groups. Using univariate and multivariate regression analyses, we found that an ApoB/ApoA1 ratio of ≥ 1.15 was an independent predictor of DKD patients progressing to RRT.

CONCLUSION

An elevated ApoB/ApoA1 ratio of ≥ 1.15 was an independent predictor of DKD progression to RRT. A further study with a larger sample is needed to confirm the findings of the current study.

Concepts and Controversies: Lipid Management in Patients with Chronic Kidney Disease

Atherosclerotic cardiovascular disease (ASCVD) remains an important contributor of morbidity and mortality in patients with chronic kidney disease (CKD). CKD is recognized as an important risk enhancer that identifies patients as candidates for more intensive low-density lipoprotein (LDL) cholesterol lowering. However, there is controversy regarding the efficacy of lipid-lowering therapy, especially in patients on dialysis. Among patients with CKD, not yet on dialysis, there is clinical trial evidence for the use of statins with or without ezetimibe to reduce ASCVD events. Newer cholesterol lowering agents have been introduced for the management of hyperlipidemia to reduce ASCVD, but these therapies have not been tested in the CKD population except in secondary analyses of patients with primarily CKD stage 3. This review summarizes the role of hyperlipidemia in ASCVD and treatment strategies for hyperlipidemia in the CKD population.

Apolipoprotein B and renal function: across-sectional study from the China health and nutrition survey

BACKGROUND

Chronic kidney disease (CKD) is a worldwide public health problem characterized by changes in kidney structure and function, usually leading to a loss of kidney function. The identification of risk factors and management of patients with early-stage CKD may slow or prevent the progression to end-stage renal disease.

METHODS

This study used the population-based cohort database from the China Health and Nutrition Survey (CHNS). Data from 11,978 patients were collected from the 2009 to 2011 wave of the CHNS. After removing patients with missing data, we finally included 8322 participants. A cross-sectional design was used to assess the association between Apolipoprotein B (Apo-B) levels and CKD. We used overlapping covariates to develop 5 models to evaluate the odds ratios.

RESULTS

Among the study participants, patients with estimated glomerular filtration rates (eGFR) < 60 ml/min/1.73m2were more likely to have increased Apo-B levels (> 1.2 mmol/L, 19.41%), likely to be elderly (> 65 years, 61.76%), likely to be female (61.21%), and likely to be less educated (< 6 years and > 6 & ≤12 years, 32.07 and 52.44%, respectively).The significant association between Apo-B and CKD defined by eGFR even after adjusting for confounders including demographic characteristics, nutritional status, comorbidities, biochemical indicators, and lifestyle factors. In addition, stratified analyses showed that young and middle age (< 65 years), being overweight (body mass index [BMI] > 25 kg/m2), and hyperuricemia were associated with higher risks of CKD stages.

CONCLUSIONS

The results of this Chinese population-based study revealed a strong positive correlation between Apo-B and CKD stages. The current findings were obtained from an epidemiologic study; therefore, these data cannot directly address the mechanisms of disease progression. The underlying mechanisms require analysis in future independent validation and prospective cohort studies.

Lipid-modifying therapy in chronic kidney disease: Pathophysiological and clinical considerations

Chronic kidney disease (CKD), which affects >10% of the population worldwide, is associated with a dramatically increased rate of cardiovascular disease (CVD). More people with CKD will die from CVD than develop end-stage renal disease with dialysis-dependency. However, the contribution of classical atherosclerotic cardiovascular risk factors is less evident than in the general population. Particularly, the relationship between dyslipidemia and CVD morbidity and mortality in CKD patients is not as evident as in the general population. While LDL cholesterol-lowering drugs such as statins significantly reduce the rate of cardiovascular events in the general population, their role in patients with end-stage renal disease has been questioned. This could be caused by a shift from atherosclerotic to non-atherosclerotic CVD in patients with advanced CKD, which cannot be effectively prevented by lipid-lowering drugs. In addition, many lines of evidence suggest that impaired renal function directly affects the metabolism, composition and functionality of lipoproteins, which may affect their responsiveness to pharmacological interventions. In this review, we highlight the challenges for the therapeutic application of lipid-lowering treatment strategies in CKD and discuss why treatment strategies used in the general population cannot be applied uncritically to CKD patients.

Lipid management in patients with chronic kidney disease

An increased risk of cardiovascular disease, independent of conventional risk factors, is present even at minor levels of renal impairment and is highest in patients with end-stage renal disease (ESRD) requiring dialysis. Renal dysfunction changes the level, composition and quality of blood lipids in favour of a more atherogenic profile. Patients with advanced chronic kidney disease (CKD) or ESRD have a characteristic lipid pattern of hypertriglyceridaemia and low HDL cholesterol levels but normal LDL cholesterol levels. In the general population, a clear relationship exists between LDL cholesterol and major atherosclerotic events. However, in patients with ESRD, LDL cholesterol shows a negative association with these outcomes at below average LDL cholesterol levels and a flat or weakly positive association with mortality at higher LDL cholesterol levels. Overall, the available data suggest that lowering of LDL cholesterol is beneficial for prevention of major atherosclerotic events in patients with CKD and in kidney transplant recipients but is not beneficial in patients requiring dialysis. The 2013 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline for Lipid Management in CKD provides simple recommendations for the management of dyslipidaemia in patients with CKD and ESRD. However, emerging data and novel lipid-lowering therapies warrant some reappraisal of these recommendations.

The Protective Role of Adiponectin for Lipoproteins in End-Stage Renal Disease Patients: Relationship with Diabetes and Body Mass Index

Cardiovascular disease (CVD) events are the main causes of death in end-stage renal disease (ESRD) patients on dialysis. The number and severity of CVD events remain inappropriate and difficult to explain by considering only the classic CVD risk factors. Our aim was to clarify the changes and the relationship of lipoprotein subfractions with other CVD risk factors, namely, body mass index (BMI) and adipokines, inflammation and low-density lipoprotein (LDL) oxidation, and the burden of the most prevalent comorbidities, diabetes mellitus (DM) and hypertension (HT). We studied 194 ESRD patients on dialysis and 22 controls; lipid profile, including lipoprotein subpopulations and oxidized LDL (oxLDL), C-reactive protein (CRP), adiponectin, leptin, and paraoxonase 1 activity were evaluated. Compared to controls, patients presented significantly lower levels of cholesterol, high-density lipoprotein cholesterol (HDLc), LDLc, oxLDL, and intermediate and small HDL and higher triglycerides, CRP, adiponectin, large HDL, very-low-density lipoprotein (VLDL), and intermediate-density lipoprotein- (IDL) B. Adiponectin levels correlated positively with large HDL and negatively with intermediate and small HDL, oxLDL/LDLc, and BMI; patients with DM (n = 17) and with DM+HT (n = 70), as compared to patients without DM or HT (n = 69) or only with HT (n = 38), presented significantly higher oxLDL, oxLDL/LDLc, and leptin and lower adiponectin. Obese patients (n = 45), as compared to normoponderal patients (n = 81), showed lower HDLc, adiponectin, and large HDL and significantly higher leptin, VLDL, and intermediate and small HDL. In ESRD, the higher adiponectin seems to favor atheroprotective HDL modifications and protect LDL particles from oxidative atherogenic changes. However, in diabetic and obese patients, adiponectin presents the lowest values, oxLDL/LDLc present the highest ones, and the HDL profile is the more atherogenic. Our data suggest that the coexistence of DM and adiposity in ESRD patients on dialysis contributes to a higher CVD risk, as showed by their lipid and adipokine profiles.

Cardiovascular Disease and Diabetic Kidney Disease

Diabetic kidney disease commonly is associated with an increased risk of cardiovascular disease. There are traditional common risk factors for both conditions including hypertension and poor glycemic control. However, it is likely that there are other pathophysiological mechanisms that explain the clinical phenomenon of increased cardiovascular disease in diabetic patients with chronic kidney and vice versa. Current management of both conditions includes aggressive glucose and blood pressure control. The protective role of treating dyslipidemia has been shown for cardiovascular disease, but the results for renal disease are not as clear. The advent of new classes of glucose-lowering agents such as sodium glucose co-transporter2 inhibitors and glucagon-like peptide-1 agonists has resulted in impressive effects on both cardiovascular and renal disease in diabetes. However, how these drugs act independently of glucose lowering to confer both kidney and cardiovascular protection has not been fully elucidated. Nevertheless, these new treatments provide optimism for reducing both microvascular and macrovascular complications in diabetes, which represent the major causes of morbidity and premature mortality in this condition.

A Population-Based Study on the Prevalence and Risk Factors of Chronic Kidney Disease in the Adult Population of Shiraz, Southern Iran

Background:

Currently, we are facing a significant increase in the new cases of the end-stage renal disease in developing countries. Hence, it seems vital to work on strategies aimed at reducing its development and progression. Determining the related risk factors can provide an insight into achieving these policymaking goals. Therefore, this study was conducted to identify risk factors associated with chronic kidney disease (CKD) in the Iranian adult population.

Materials and Methods:

This cross-sectional study was performed in Shiraz, Southern Iran, through a cluster random sampling technique that involved 819 subjects, including 340 male and 479 female adult participants. Factors such as the body mass index, waist circumference, blood pressure, and biochemical profile were determined. We evaluated the prevalence of CKD according to the glomerular filtration rate (GFR), as well as possible risk factors associated with it. GFR was calculated on the basis of the "Chronic Kidney Disease Epidemiology Collaboration" creatinine equation.

Results:

The cluster comprised 58.5% females and 41.5% males. The mean age of our participants was 43.0 ± 14.0 years. Our results showed that 16.6% of adult urban inhabitants in Iran had CKD (stages 3 to 5, eGFR ≤60), that is, GFR less than 60 mL/min/1.73 m2. The proportion of participants having hypertension, obesity, high waist circumference, diabetes mellitus, and history of cardiovascular disease was 17.3%, 19.3%, 35%, 9.4%, and 5.3%, respectively. Multiple regression analysis indicated an independent correlation between age, sex, dyslipidemia, and hypertension with CKD.

Conclusion:

This study indicates that CKD is a substantial health burden in Iranian adult population. Additionally, the results of this study addressed the importance of integrated strategies that aimed to identify, prevent, and treat noncommunicable diseases fueling the development of CKD.

Atorvastatin and carnitine combination versus atorvastatin alone impacts on the lipid profile of haemodialyzed patients: A randomised clinical trial

Introduction: Dyslipidemia is one of the most common problems in hemodialysis patients and healthcare system. Some studies have suggested the use of carnitine in the treatment of dyslipidemia in hemodialysis patients. This study was carried out aiming to evaluate the effect of atorvastatin and carnitine combination versus atorvastatin alone on the lipid profile of hemodialyzed patients. Methods: In this clinical trial, 50 hemodialysis patients referred to the educational centres of Tabriz University of Medical Sciences, Tabriz, Iran, for haemodialysis were enrolled. Patients were randomly assigned into two groups. In the first group, patients were treated with carnitine (1000 mg three times daily) and atorvastatin (10-80 mg/day based on the baseline lipid profile of the patients) and in the second group, the patients were treated with atorvastatin alone for six months. The levels of triglyceride (TG), cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and haemoglobin before and after intervention were compared. The side effects of carnitine administration were also evaluated. Results: Results showed that TG, cholesterol, and LDL levels were significantly lower in the carnitine group compared to those in the other group at the end of study (P < 0.050). In addition, HDL and haemoglobin levels were significantly higher in the carnitine group in comparison to the other group (P < 0.050). No major side effects of carnitine were observed among the patients. Conclusion: The use of carnitine plus atorvastatin combination is an effective and safe method in the treatment of dyslipidemia in patients undergoing hemodialysis without imposing significant side effects.

Circulating Biomarker Levels in Patients With Stage 5 Chronic Kidney Disease With Respect to Neurovascular Diseases

The prevalence of neurocognitive deficits remains high in patients with stage 5 chronic kidney disease (CKD5D). Major contributors to such deficits include stroke, cervical carotid artery disease (CCAD), and intracranial atherosclerotic disease (ICAD). The risk of developing these dysfunctional vascular processes is facilitated by the chronic inflammation associated with renal failure. Plasma levels of 10 circulating biomarkers in patients with CKD5D (n = 78-90) were quantified using the sandwich enzyme linked immune sorbent assay method. Biomarkers for this study included kidney injury molecule-1, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), neutrophil gelatinase-associated lipocalin, interleukin-18, endothelin 1, calcifediol, parathyroid hormone, platelet-derived growth factor, microparticles-expressing tissue factor, and lipoprotein(a) (Lp(a)). Of the 90 patients with CKD5D, 30 had CCAD, 24 had ICAD, and 22 had stroke. Lp(a) level was significantly elevated in patients with CKD5D with comorbid ICAD compared to those without (125.70 ± 10.03 ng/mL vs 97.16 ± 5.97 ng/mL; P = .0065). NT-proBNP level was also significantly elevated in patients with CKD5D with comorbid stroke diagnosis compared to those without stroke history, once patients with a diagnosis of heart failure (HF) were excluded (14.84 ± 2.80 ng/mL vs 9.06 ± 1.27 ng/mL; P = .0283). Profiling levels of Lp(a) and NT-ProBNP could thus be useful in the risk stratification of ICAD and stroke, respectively, in the CKD5D population.

Managing Diabetes and Cardiovascular Risk in Chronic Kidney Disease Patients

We discuss mechanisms of increased cardiovascular disease (CVD) in patients with chronic kidney disease (CKD) and strategies for managing cardiovascular (CV) risk in these patients. Our focus was mainly on decreasing CV events and progression of microvascular complications by reducing levels of glucose and lipids. We searched PubMed with no limit on the date of the article. All articles were discussed among all authors. We chose pertinent articles, and searched their references in turn for additional relevant publications.

Chronic kidney disease stage affects small, dense low-density lipoprotein but not glycated low-density lipoprotein in younger chronic kidney disease patients: a cross-sectional study

Background

Small, dense low-density lipoprotein (sd-LDL) and glycated LDL (g-LDL) have been associated with cardiovascular disease (CVD) in chronic kidney disease (CKD) in patients >60 years of age. Since young adult and paediatric patients have shorter exposure to Framingham-type risk factors, our study aims to determine whether younger CKD patients exhibit the same sd-LDL and g-LDL pattern.

Methods

After ethics board approval, this cross-sectional study was conducted at two universities with 44 patients (mean ± standard deviation age 12.6 ± 4.9, range 2-24 years) with CKD stage of 1-5. Laboratory parameters studied were Cystatin C (CysC), CysC estimated glomerular filtration rate (eGFR) (calculated from the Filler formula), sd-LDL, g-LDL and albumin. Lipid samples were measured for sd-LDL and g-LDL using ELISA. Non-linear correlation analysis was performed to determine the relationship between g-LDL, sd-LDL and eGFR. Clinical Trials Registration is at clinicaltrials.gov, NCT02126293, https://clinicaltrials.gov/ct2/show/NCT02126293.

Results

Triglycerides, but not total cholesterol and calculated LDL, were associated with CKD stages (ANOVA P = 0.0091). As in adults, sd-LDL was significantly associated with CKD stages (ANOVA P = 0.0133), CysC eGFR (r = -0.6495, P < 0.00001), and body mass index (r = -0.3895, P = 0.0189), but not with age. By contrast, there was no significant correlation between g-LDL and CKD stages or CysC eGFR (P = 0.9678).

Conclusions

Our study demonstrates that only triglycerides and sd-LDL were associated with CKD stages in this young cohort without confounding Framingham-type CVD risk factors. While larger studies are needed, this study suggests that lowering sd-LDL levels may be a potential target to ameliorate the long-term CVD risks in paediatric CKD patients.

Dyslipidemia in patients with chronic kidney disease

Chronic kidney disease (CKD) is associated with high risk for cardiovascular disease (CVD). This association is multifactorial, but CKD is often associated with dyslipidemia, which likely contributes. Patients with CKD have dyslipidemia even at early stages of renal dysfunction and dyslipidemia tends to progress with deterioration of kidney function. The dyslipidemia in CKD is largely due to increased triglyceride levels, decreased HDL-C and varying levels of LDL-C. Current management of CKD may also affect lipid levels. Robust clinical trials demonstrate that statins are safe and efficacious in both lipid lowering and prevention of CVD events in pre-end stage CKD and post-transplant. However, there is no evidence of improved CVD outcomes with statin use in dialysis patients. This review will focus on mechanisms underlying dyslipidemia in CKD and clinical trial evidence for lipid lowering therapy in patients with CKD.

Do HDL and LDL subfractions play a role in atherosclerosis in end-stage renal disease (ESRD) patients?

BACKGROUND

Significantly increased cardiovascular mortality in patients with chronic kidney (CKD) disease cannot be explained by traditional risk factors. Recent studies revealed that the quality of HDL and LDL cholesterol may be more important than their serum levels. The aim of this study was to assess which LDL and HDL subfractions were more abundant in end-stage renal disease (ESRD) patients and to analyse whether subfraction distribution could be associated with accelerated atherosclerotic processes.

METHODS

This study included 50 ESRD patients undergoing dialysis and 20 healthy volunteers. LDL and HDL subfractions were analysed in serum with the use of Lipoprint system. All patients had intima-media thickness (IMT) measured.

RESULTS

Statistically significant differences in subfractions between control and study group were observed in case of: HDL1 (p < 0.0001), HDL2 (p = 0.009), HDL3 (p < 0.0001), HDL4 (p = 0.003), HDL5 (p = 0.01), HDL7 (p < 0.0001), HDL8 (p < 0.0001), HDL9 (p < 0.0001), HDL10 (p < 0.0001), large HDL (p < 0.0001), HDL Small (p < 0.0001) as well as IDL-B (p = 0.014), IDLA (p = 0.011), LDL2 (p = 0.007). Significant differences were also observed in HDL and LDL subfraction distribution between haemodialysis patients with normal and increased IMT: HDL6 (p = 0.020), HDL Large (HDL1-3) (p = 0.017), HDL Intermediate (HDL4-7) (p = 0.017).

CONCLUSIONS

This study revealed that ESRD influenced HDL subfractions. In HD patients, large HDL subfractions are more abundant while small HDL fraction is more frequent in healthy persons. It failed to show the influence of end-stage disease on LDL subfraction levels. Shift in HDL subfractions might be responsible for the increased risk of atherosclerosis in CKD patients.

Triglyceride Treatment in the Age of Cholesterol Reduction

Cholesterol reduction has markedly reduced major cardiovascular disease (CVD) events and shown regression of atherosclerosis in some studies. However, CVD has for decades also been associated with increased levels of circulating triglyceride (TG)-rich lipoproteins. Whether this is due to a direct toxic effect of these lipoproteins on arteries or whether this is merely an association is unresolved. More recent genetic analyses have linked genes that modulate TG metabolism with CVD. Moreover, analyses of subgroups of hypertriglyceridemic (HTG) subjects in clinical trials using fibric acid drugs have been interpreted as evidence that TG reduction reduces CVD events. This review will focus on how HTG might cause CVD, whether TG reduction makes a difference, what pathophysiological defects cause HTG, and what options are available for treatment.

Lipidomic Signature of Progression of Chronic Kidney Disease in the Chronic Renal Insufficiency Cohort

Introduction

Human studies report conflicting results on the predictive power of serum lipids on the progression of chronic kidney disease. We aimed to systematically identify the lipids that predict progression to end-stage kidney disease.

Methods

From the Chronic Renal Insufficiency Cohort, 79 patients with chronic kidney disease stages 2 to 3 who progressed to end-stage kidney disease over 6 years of follow-up were selected and frequency matched by age, sex, race, and diabetes with 121 nonprogressors with less than 25% decline in estimated glomerular filtration rate during the follow-up. The patients were randomly divided into training and test sets. We applied liquid chromatography-mass spectrometry-based lipidomics on visit year 1 samples.

Results

We identified 510 lipids, of which the top 10 coincided with false discovery threshold of 0.058 in the training set. From the top 10 lipids, the abundance of diacylglycerols and cholesteryl esters was lower, but that of phosphatidic acid 44:4 and monoacylglycerol 16:0 was significantly higher in progressors. Using logistic regression models, a multimarker panel consisting of diacylglycerols and monoacylglycerol independently predicted progression. The c-statistic of the multimarker panel added to the base model consisting of estimated glomerular filtration rate and urine protein-to-creatinine ratio as compared with that of the base model was 0.92 (95% confidence interval: 0.88–0.97) and 0.83 (95% confidence interval: 0.76–0.90, P < 0.01), respectively, an observation that was validated in the test subset.

Discussion

We conclude that a distinct panel of lipids may improve prediction of progression of chronic kidney disease beyond estimated glomerular filtration rate and urine protein-to-creatinine ratio when added to the base model.

Increased HDL Size and Enhanced Apo A-I Catabolic Rates Are Associated With Doxorubicin-Induced Proteinuria in New Zealand White Rabbits

The catabolism and structure of high-density lipoproteins (HDL) may be the determining factor of their atheroprotective properties. To better understand the role of the kidney in HDL catabolism, here we characterized HDL subclasses and the catabolic rates of apo A-I in a rabbit model of proteinuria. Proteinuria was induced by intravenous administration of doxorubicin in New Zealand white rabbits (n = 10). HDL size and HDL subclass lipids were assessed by electrophoresis of the isolated lipoproteins. The catabolic rate of HDL-apo A-I was evaluated by exogenous radiolabelling with iodine-131. Doxorubicin induced significant proteinuria after 4 weeks (4.47 ± 0.55 vs. 0.30 ± 0.02 g/L of protein in urine, P < 0.001) associated with increased uremia, creatininemia, and cardiotoxicity. Large HDL2b augmented significantly during proteinuria, whereas small HDL3b and HDL3c decreased compared to basal conditions. HDL2b, HDL2a, and HDL3a subclasses were enriched with triacylglycerols in proteinuric animals as determined by the triacylglycerol-to-phospholipid ratio; the cholesterol content in HDL subclasses remained unchanged. The fractional catabolic rate (FCR) of [(131)I]-apo A-I in the proteinuric rabbits was faster (FCR = 0.036 h(-1)) compared to control rabbits group (FCR = 0.026 h(-1), P < 0.05). Apo E increased and apo A-I decreased in HDL, whereas PON-1 activity increased in proteinuric rabbits. Proteinuria was associated with an increased number of large HDL2b particles and a decreased number of small HDL3b and 3c. Proteinuria was also connected to an alteration in HDL subclass lipids, apolipoprotein content of HDL, high paraoxonase-1 activity, and a rise in the fractional catabolic rate of the [(131)I]-apo A-I.

Plasma Nitration of High-Density and Low-Density Lipoproteins in Chronic Kidney Disease Patients Receiving Kidney Transplants

BACKGROUND

Functional abnormalities of high-density lipoprotein (HDL) could contribute to cardiovascular disease in chronic kidney disease patients. We measured a validated marker of HDL dysfunction, nitrated apolipoprotein A-I, in kidney transplant recipients to test the hypothesis that a functioning kidney transplant reduces serum nitrated apoA-I concentrations.

METHODS

Concentrations of nitrated apoA-I and apoB were measured using indirect sandwich ELISA assays on sera collected from each transplant subject before transplantation and at 1, 3, and 12 months after transplantation. Patients were excluded if they have history of diabetes, treatment with lipid-lowering medications or HIV protease inhibitors, prednisone dose > 15 mg/day, nephrotic range proteinuria, serum creatinine > 1.5 mg/dL, or active inflammatory disease. Sera from 18 transplanted patients were analyzed. Four subjects were excluded due to insufficient data. Twelve and eight patients had creatinine < 1.5 mg/dL at 3 and 12 months after transplantation, respectively. RESULTS. Nitrated apoA-I was significantly reduced at 12 months after transplantation (p = 0.039). The decrease in apoA-I nitration was associated with significant reduction in myeloperoxidase (MPO) activity (p = 0.047). In contrast to apoA-I, nitrated apoB was not affected after kidney transplantation.

CONCLUSIONS

Patients with well-functioning grafts had significant reduction in nitrated apoA-I 12 months after kidney transplantation. Further studies are needed in a large cohort to determine if nitrated apoA-I can be used as a valuable marker for cardiovascular risk stratification in chronic kidney disease.

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

AIM

Chronic kidney disease (CKD) may lead to reduced concentrations of high-density lipoprotein (HDL) and its subfractions (HDL2 and HDL3), and damage them via inflammation and oxidative stress. The present study aimed to determine the contribution of such changes to cardiovascular disease (CVD) in patients with CKD.

METHODS

The levels of total cholesterol, low-density lipoprotein cholesterol, HDL-C, HDL2, HDL3, apolipoproteins, malondialdehyde-modified LDL (MDA-LDL), oxidized (ox) HDL, oxHDL2, and oxHDL3 were measured in blood samples from patients with CKD (stages 2-5, n=86) who were not on dialysis and from patients undergoing hemodialysis (CKD stage 5D, n=25). The patients were followed up for 28±9 months after baseline examinations and CVD events were recorded.

RESULT

The levels of HDL3 and ApoA1 in HDL3 fraction decreased according to CKD severity, whereas those of HDL2 and ApoA1 in HDL2 fraction did not differ. The levels of oxHDL were similar across CKD stages. The levels of oxHDL3 and MDA-LDL were decreased, whereas those of oxHDL2 increased according to CKD severity. Multivariate analyses using the Cox proportional hazards model selected high levels of oxHDL and its subfractions, and those adjusted with HDL-C and HDL subfractions or ApoA1 in HDL fractions respectively, compared with HDL-C and HDL subfractions or ApoA1 in HDL fractions alone as independent risk factors for CVD events.

CONCLUSION

The levels of HDL subfractions and their oxidized subfraction particles differed among patients with CKD. The increasing levels of oxHDL subfractions might cause a high frequency of CVD events in such patients.

Residual Cardiovascular Risk in Chronic Kidney Disease: Role of High-density Lipoprotein

Although reducing low-density lipoprotein-cholesterol (LDL-C) levels with lipid-lowering agents (statins) decreases cardiovascular disease (CVD) risk, a substantial residual risk (up to 70% of baseline) remains after treatment in most patient populations. High-density lipoprotein (HDL) is a potential contributor to residual risk, and low HDL-cholesterol (HDL-C) is an established risk factor for CVD. However, in contrast to conventional lipid-lowering therapies, recent studies show that pharmacologic increases in HDL-C levels do not bring about clinical benefits. These observations have given rise to the concept of dysfunctional HDL where increases in serum HDL-C may not be beneficial because HDL loss of function is not corrected by or even intensified by the therapy. Chronic kidney disease (CKD) increases CVD risk, and patients whose CKD progresses to end-stage renal disease (ESRD) requiring dialysis are at the highest CVD risk of any patient type studied. The ESRD population is also unique in its lack of significant benefit from standard lipid-lowering interventions. Recent studies indicate that HDL-C levels do not predict CVD in the CKD population. Moreover, CKD profoundly alters metabolism and composition of HDL particles and impairs their protective effects on functions such as cellular cholesterol efflux, endothelial protection, and control of inflammation and oxidation. Thus, CKD-induced perturbations in HDL may contribute to the excess CVD in CKD patients. Understanding the mechanisms of vascular protection in renal disease can present new therapeutic targets for intervention in this population.

Top-down lipidomics of low density lipoprotein reveal altered lipid profiles in advanced chronic kidney disease

This study compared the molecular lipidomic profile of LDL in patients with nondiabetic advanced renal disease and no evidence of CVD to that of age-matched controls, with the hypothesis that it would reveal proatherogenic lipid alterations. LDL was isolated from 10 normocholesterolemic patients with stage 4/5 renal disease and 10 controls, and lipids were analyzed by accurate mass LC/MS. Top-down lipidomics analysis and manual examination of the data identified 352 lipid species, and automated comparative analysis demonstrated alterations in lipid profile in disease. The total lipid and cholesterol content was unchanged, but levels of triacylglycerides and N-acyltaurines were significantly increased, while phosphatidylcholines, plasmenyl ethanolamines, sulfatides, ceramides, and cholesterol sulfate were significantly decreased in chronic kidney disease (CKD) patients. Chemometric analysis of individual lipid species showed very good discrimination of control and disease sample despite the small cohorts and identified individual unsaturated phospholipids and triglycerides mainly responsible for the discrimination. These findings illustrate the point that although the clinical biochemistry parameters may not appear abnormal, there may be important underlying lipidomic changes that contribute to disease pathology. The lipidomic profile of CKD LDL offers potential for new biomarkers and novel insights into lipid metabolism and cardiovascular risk in this disease.

Comparison of the efficacy and safety profile of morning administration of controlled-release simvastatin versus evening administration of immediate-release simvastatin in chronic kidney disease patients with dyslipidemia

PURPOSE

Evening administration of the conventional immediate-release (IR) formulation of simvastatin is recommended because of its short half-life (1.9 hours). In a healthy population, morning administration of a controlled-release (CR) formulation of simvastatin was shown to have equivalent lipid-lowering efficacy and a safety profile similar to that of evening doses of IR simvastatin. The present study aimed to verify noninferiority and to compare the safety of morning administration of CR simvastatin with that of evening administration of IR simvastatin in patients with chronic kidney disease (CKD) who have dyslipidemia.

METHODS

The present study was a prospective, multicenter, double-blind, Phase IV trial with an active comparator. We randomly assigned 122 patients with CKD and dyslipidemia to 1 of 2 drug administration groups: morning administration of CR simvastatin 20 mg (test group) and evening administration of IR simvastatin 20 mg (control group). After 8 weeks, the treatment outcomes and adverse effects of the 2 treatments were compared.

FINDINGS

The mean (SD) percentage of change in serum LDL-C at the end of treatment was -35.1% (15.7%) for the test group and -35.6% (14.6%) for the control group. The difference between the 2 groups was not significant (P = 0.858). The 95% CI of the difference in the percentage of change of LDL-C between the test and control groups was -6.0 to 5.0. There was no difference in the percentage of change of total cholesterol (-24.3% [12.5%] vs -26.5% [12.0%], P = 0.317), triglyceride (-10.6% [35.1%] vs -12.4% [33.2%], P = 0.575) and HDL-C (10.2% [20.7%] vs 4.5% [11.4%], P = 0.064). Treatment-related adverse events were similar in both groups (10 events in the test group vs 8 events in the control group, P = 0.691).

IMPLICATIONS

The efficacy of morning administration of CR simvastatin was noninferior to evening administration of IR simvastatin in patients with CKD. Furthermore, the safety profile analysis showed no significant difference between the 2 treatments. Morning administration of CR simvastatin is expected to increase patient compliance and therefore better control of dyslipidemia in CKD patients.

Treatment options for hypertriglyceridemia: from risk reduction to pancreatitis

While there has been considerable focus on the role and treatment of LDL cholesterol levels, a definitive role of triglycerides in the management of cardiovascular disease has been uncertain. Notably, with increasing triglyceride levels, there is a parallel increase in cholesterol levels carried by triglyceride-rich lipoproteins, which has prompted interest in the use of non-HDL cholesterol levels as a tool guiding interventions. Recent studies have provided evidence for an independent role of triglyceride levels as a cardiovascular risk factor, and recently, an Endocrine Society guideline was published for treatment of hypertriglyceridemia. In contrast to the relative uncertainty regarding triglycerides and cardiovascular disease, a role of very high triglyceride levels as a risk factor for pancreatitis has been well known. The present paper summarizes the underlying evidence for a risk role for triglyceride levels in cardiovascular disease and pancreatitis, current treatment recommendations and areas of future research.

Relation of serum lipids and lipoproteins with progression of CKD: The CRIC study

BACKGROUND AND OBJECTIVES

Hyperlipidemia is common in patients with CKD. The objective of this study was to evaluate whether measures of plasma lipids and lipoproteins predict progression of kidney disease in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Prospective cohort study in adults (n=3939) with CKD aged 21-74 years recruited between 2003 and 2008 and followed for a median of 4.1 years. At baseline, total cholesterol, triglycerides, very-low-density lipoprotein cholesterol (VLDL-C), LDL cholesterol (LDL-C), HDL cholesterol (HDL-C), apoA-I , apoB, and lipoprotein(a) [Lp(a)] were measured. The outcomes were composite end point of ESRD or 50% decline in eGFR from baseline (rate of change of GFR).

RESULTS

Mean age of the study population was 58.2 years, and the mean GFR was 44.9 ml/min per 1.73 m(2); 48% of patients had diabetes. None of the lipid or lipoprotein measures was independently associated with risk of the composite end point or rate of change in GFR. However, there were significant (P=0.01) interactions by level of proteinuria. In participants with proteinuria<0.2 g/d, 1-SD higher LDL-C was associated with a 26% lower risk of the renal end point (hazard ratio [HR], 0.74; 95% confidence interval [95% CI], 0.59 to 0.92; P=0.01), and 1-SD higher total cholesterol was associated with a 23% lower risk of the renal end point (HR, 0.77; 95% CI, 0.62 to 0.96; P=0.02). In participants with proteinuria>0.2 g/d, neither LDL-C (HR, 0.98; 95% CI, 0.98 to 1.05) nor total cholesterol levels were associated with renal outcomes. Treatment with statins was reported in 55% of patients and was differential across lipid categories.

CONCLUSIONS

In this large cohort of patients with CKD, total cholesterol, triglycerides, VLDL-C, LDL-C, HDL-C, apoA-I, apoB, and Lp(a) were not independently associated with progression of kidney disease. There was an inverse relationship between LDL-C and total cholesterol levels and kidney disease outcomes in patients with low levels of proteinuria.

Effect of serum FGF-23, MGP and fetuin-A on calcium-phosphate metabolism in maintenance hemodialysis patients

This study was aimed to explore the role of serum fibroblast growth factor (FGF)-23, matrix Gla protein (MGP) and fetuin-A in the calcium-phosphate metabolism and their predicting value in coronary artery calcification in maintenance hemodialysis (MHD) patients. This study included 64 patients who receive hemodialysis in our hospital. The serum FGF-23, MGP and fetuin-A were analyzed by enzyme-linked immunosorbent assay (ELlSA). Coronary artery calcification score (CACS) was evaluated by coronary artery computed tomography scan. The 64 patients (30 males, 34 females, 60.6 ± 11.3 years of age) received an average dialysis vintage of 6.88 ± 2.94 years. We divided the CACS into three levels, and 13 (20.31%), 16 (25%), and 35 (54.69%) exhibited a CACS of 0-100, 100-400, and >400, respectively. Dialysis vintage, serum FGF-23, fetuin-A, phosphorus and high-density lipoprotein-C levels were identified as independent variables of CACS by stepwise multiple regression analysis. The area under receiver operating characteristic curve indicated that serum FGF-23 and fetuin-A were useful for identifying CAC in MHD patients. The cut-off value corresponding to the highest Youden's index was serum FGF-23 ≥ 256 pg/mL and fetuin-A ≤ 85 μg/mL, which was defined as the optimal predictors of CAC. Different combinations of serum FGF-23 and fetuin-A in parallel or in series effectively boosted the identification of CAC. The incidence of CAC is high in MHD patients. Serum FGF-23 and fetuin-A levels are closely correlated with CAC.

Lipoprotein metabolism and CKD: overview

Patients with chronic kidney disease (CKD) frequently display abnormalities of plasma lipids and lipoproteins. These abnormalities include hypertriglyceridemia associated with elevated levels of very low-density lipoproteins (VLDLs) and chylomicrons. There is often also an increase in the concentration of the atherogenic, cholesterol-enriched remnants of VLDLs and chylomicrons. The concentration of low-density lipoprotein cholesterol is usually normal, but there is frequently a decrease in concentration of the cardio-protective high-density lipoproteins. There is also often an increase in the concentration of the atherogenic lipoprotein (a) particles. This article provides an overview of plasma lipoprotein transport and identifies mechanisms responsible for the abnormalities observed in patients with CKD.

Post-transcriptional nature of uremia-induced downregulation of hepatic apolipoprotein A-I production

Chronic kidney disease is associated with premature death from cardiovascular disease, which is, in part, driven by high density lipoprotein deficiency and dysfunction. One of the main causes of high density lipoprotein deficiency in chronic kidney disease is diminished plasma apolipoprotein (Apo)A-I level. Plasma ApoA-I is reduced in dialysis patients and hepatic ApoA-I messenger RNA (mRNA) is decreased in the uremic rats. This study explored the mechanism of uremia-induced downregulation of ApoA-I. Human hepatoma derived cells were incubated in media containing whole plasma or plasma subfractionation from normal subjects and patients with end stage renal disease pre- and posthemodialysis. Cells and culture media were isolated to measure ApoA-I protein and mRNA. ApoA-I promoter activity was measured using transfection with a luciferase promoter construct containing the -2096 to +293 segment of ApoA-I gene. Finally, effect of uremic and control plasma was assessed on ApoA-I RNA stability. Exposure to uremic plasma significantly reduced ApoA-I mRNA expression and ApoA-I protein production. These effects were reversed by replacing uremic plasma with normal plasma. Although no difference in ApoA-I promoter activity was found between cells exposed to uremic and normal plasma, uremic plasma significantly reduced ApoA-I RNA stability. Experiments using plasma subfractions revealed that the inhibitory effect of uremic plasma on ApoA-I mRNA expression resides in fractions containing molecules larger but not smaller than 30 kd. The pre- and postdialysis plasma exerted an equally potent inhibitory effect on ApoA-I mRNA abundance. Uremia lowers ApoA-I production by reducing its RNA stability. The inhibitory effect of uremic milieu on ApoA-I mRNA expression is mediated by non-dialyzable molecule(s) larger than 30 kd.

Triglyceride-cholesterol imbalance across lipoprotein subclasses predicts diabetic kidney disease and mortality in type 1 diabetes: the FinnDiane Study

BACKGROUND

Circulating cholesterol (C) and triglyceride (TG) levels are associated with vascular injury in type 1 diabetes (T1DM). Lipoproteins are responsible for transporting lipids, and alterations in their subclass distributions may partly explain the increased mortality in individuals with T1DM.

DESIGN AND SUBJECTS

A cohort of 3544 individuals with T1DM was recruited by the nationwide multicentre FinnDiane Study Group. At baseline, six very low-density lipoprotein VLDL, one intermediate-density lipoprotein IDL, three low-density lipoprotein LDL and four higher high-density lipoprotein HDL subclasses were quantified by proton nuclear magnetic resonance spectroscopy. At follow-up, the baseline data were analysed for incident micro- or macroalbuminuria (117 cases in 5.3 years), progression from microalbuminuria (63 cases in 6.1 years), progression from macroalbuminuria (109 cases in 5.9 years) and mortality (385 deaths in 9.4 years). Univariate associations were tested by age-matched cases and controls and multivariate lipoprotein profiles were analysed using the self-organizing map (SOM).

RESULTS

TG and C levels in large VLDL were associated with incident albuminuria, TG and C in medium VLDL were associated with progression from microalbuminuria, and TG and C in all VLDL subclasses were associated with mortality. Large HDL-C was inversely associated with mortality. Three extreme phenotypes emerged from SOM analysis: (i) low C (<3% mortality), (ii) low TG/C ratio (6% mortality), and (iii) high TG/C ratio (40% mortality) in all subclasses.

CONCLUSIONS

TG-C imbalance is a general lipoprotein characteristic in individuals with T1DM and high vascular disease risk.

Lipid abnormalities in patients with chronic kidney disease: implications for the pathophysiology of atherosclerosis

Cardiovascular disease is increased in patients with chronic kidney disease (CKD) and is the principle cause of morbidity and mortality in these patients. In patients with stage 5 CKD, structural changes in the myocardium have been implicated as the principle cardiovascular processes leading to this increase in morbidity and mortality, while atherosclerotic events including acute myocardial infarction and strokes are responsible for approximately 10-15% of cardiovascular deaths. Dyslipidemia is common in CKD patients and is usually not characterized by elevated cholesterol levels, except in patients with marked proteinuria. Increased triglyceride levels in conjunction with decreased high-density lipoprotein levels are the commonest qualitative abnormality. Characteristically, abnormalities in the metabolism of apolipoprotein (apo) B-containing lipoproteins have been described, including both gut derived (apoB-48) as well as those produced by hepatic synthesis (apoB-100). A decrease in enzymatic delipidation as well as reduced receptor removal of these lipoproteins both contribute to the increased levels of these apo-B-containing particles and their remnants (which are believed to be highly atherogenic). Abnormalities in the metabolism of apoA-containing lipoproteins are also present and these changes contribute to the lower levels of HDL seen. Qualitative abnormalities of these HDL particles may be associated with cellular oxidative injury and contribute to a pro-inflammatory, pro-thrombotic milieu that is frequently present in CKD patients.

Evaluation and treatment of hypertriglyceridemia: an Endocrine Society clinical practice guideline

OBJECTIVE

The aim was to develop clinical practice guidelines on hypertriglyceridemia.

PARTICIPANTS

The Task Force included a chair selected by The Endocrine Society Clinical Guidelines Subcommittee (CGS), five additional experts in the field, and a methodologist. The authors received no corporate funding or remuneration.

CONSENSUS PROCESS

Consensus was guided by systematic reviews of evidence, e-mail discussion, conference calls, and one in-person meeting. The guidelines were reviewed and approved sequentially by The Endocrine Society's CGS and Clinical Affairs Core Committee, members responding to a web posting, and The Endocrine Society Council. At each stage, the Task Force incorporated changes in response to written comments.

CONCLUSIONS

The Task Force recommends that the diagnosis of hypertriglyceridemia be based on fasting levels, that mild and moderate hypertriglyceridemia (triglycerides of 150-999 mg/dl) be diagnosed to aid in the evaluation of cardiovascular risk, and that severe and very severe hypertriglyceridemia (triglycerides of > 1000 mg/dl) be considered a risk for pancreatitis. The Task Force also recommends that patients with hypertriglyceridemia be evaluated for secondary causes of hyperlipidemia and that subjects with primary hypertriglyceridemia be evaluated for family history of dyslipidemia and cardiovascular disease. The Task Force recommends that the treatment goal in patients with moderate hypertriglyceridemia be a non-high-density lipoprotein cholesterol level in agreement with National Cholesterol Education Program Adult Treatment Panel guidelines. The initial treatment should be lifestyle therapy; a combination of diet modification and drug therapy may also be considered. In patients with severe or very severe hypertriglyceridemia, a fibrate should be used as a first-line agent.

Serum non-high-density lipoprotein cholesterol (non-HDL-C) levels and cardiovascular mortality in chronic hemodialysis patients

BACKGROUND

Non-high-density lipoprotein cholesterol (non-HDL-C) has been proposed as a predictor of cardiovascular disease (CVD) in the general population. The aim of this study was to evaluate the utility of non-HDL-C in predicting CV mortality in chronic hemodialysis (HD) patients.

METHODS

We calculated the serum non-HDL-C level of 259 HD patients by subtracting their HDL-C levels from their total cholesterol. Cox proportional hazards models were used to estimate the hazards ratio (HR) for CV mortality and the 95% confidence interval (CI). A receiver-operating characteristic (ROC) analysis was performed to estimate the relationship between sensitivity and specificity of a diagnostic parameter.

RESULTS

There were 44 deaths (17.0%) during the follow-up period, 33 (12.7%) of which were due to CVD. A multivariate Cox analysis with adjustments for age, diabetes, dialysis vintage, systolic blood pressure, serum albumin, and lipid levels showed that non-HDL-C was an independent predictor of CV mortality (HR 1.015, 95% CI 1.004-1.025, p = 0.0083). An ROC analysis showed that the plots of the non-HDL-C levels yielded significant specificity and sensitivity for predicting the risk of CVD mortality in HD patients [area under the curve (AUC) 0.62416; p = 0.0366; cutoff value 111.0 mg/dl]. The Kaplan-Meier survival curves of HD patients showed significant differences in CV mortality according to their tertiles with respect to serum non-HDL-C levels (p = 0.0165).

CONCLUSION

The results of this study suggest that serum non-HDL-C level is a significant CV mortality predictor of chronic HD patients.

Lipid abnormalities and oxidized LDL in chronic kidney disease patients on hemodialysis and peritoneal dialysis

Dyslipoproteinemia and oxidative modification of low-density lipoprotein (oxLDL) contribute to the development of oxidative stress and atherosclerosis in chronic kidney disease (CKD). On the contrary, high-density lipoprotein cholesterol (HDL-C), especially HDL3-C subtype, has protective effect against oxidative damage. There is limited evidence referring HDL-C subclass levels in patients on dialysis. This study was designed to compare lipid abnormalities and oxLDL levels in hemodialysis (HD) and peritoneal dialysis (PD) patients. Serum lipids, HDL subclasses, and oxLDL were measured in 55 patients with CKD-stage 5 (31 patients on HD and 24 patients on PD) and in 21 normal controls (NC). The results showed that in dialysis patients, triglycerides were higher than in controls (p < 0.0001) and HDL-C was significantly lower (p < 0.0001). The HDL2-C subclass concentration did not differ significantly between patients and controls, while HDL3-C was lower in patients (11 ± 0.5 mg/dL) than in NC (23 ± 1, p < 0.0001). oxLDL levels were markedly increased in patients (1.92 ± 0.29 mg/L) compared to NC (0.22 ± 0.05, p < 0.0001). Patients on PD had higher levels of cholesterol (p < 0.001) and apolipoprotein B (p < 0.05) than patients on HD. However, HDL-C, HDL-C subclasses, and oxLDL concentrations did not differ significantly between PD and HD patients. It is concluded that patients with CKD have a nearly 10-fold elevation of oxLDL compared with NC. Patients on PD have differences in the lipid profile compared with patients on HD; however, both modalities seem to possess similar potential to atherosclerosis development.