Lipoprotein Metabolism and Lipid Management in Chronic Kidney Disease

Proteinuria converts hepatic heparan sulfate to an effective proprotein convertase subtilisin kexin type 9 enzyme binding partner

Hepatic uptake of triglyceride-rich remnant lipoproteins is mediated by the low-density lipoprotein receptor, a low-density lipoprotein receptor related protein and the heparan sulfate proteoglycan, syndecan-1. Heparan sulfate proteoglycan also mediates low-density lipoprotein receptor degradation by a regulator of cholesterol homeostasis, proprotein convertase subtilisin kexin type 9 (PCSK9), thereby hampering triglyceride-rich remnant lipoproteins uptake. In this study, we investigated the effects of proteinuria on PCSK9, hepatic heparan sulfate proteoglycan and plasma triglyceride-rich remnant lipoproteins. Adriamycin-injected rats developed proteinuria, elevated triglycerides and total cholesterol (all significantly increased). Proteinuria associated with triglycerides and total cholesterol and serum PCSK9 (all significant associations) without loss of the low-density lipoprotein receptor as evidenced by immunofluorescence staining and western blotting. In proteinuric rats, PCSK9 accumulated in sinusoids, whereas in control rats PCSK9 was localized in the cytoplasm of hepatocytes. Molecular profiling revealed that the heparan sulfate side chains of heparan sulfate proteoglycan to be hypersulfated in proteinuric rats. Competition assays revealed sulfation to be a major determinant for PCSK9 binding. PCSK9 partly colocalized with hypersulfated heparan sulfate in proteinuric rats, but not in control rats. Hence, proteinuria induces hypersulfated hepatic heparan sulfate proteoglycans, increasing their affinity to PCSK9. This might impair hepatic triglyceride-rich remnant lipoproteins uptake, causing proteinuria-associated dyslipidemia. Thus, our study reveals PCSK9/heparan sulfate may be a novel target to control dyslipidemia.

Habitual coffee intake and plasma lipid profile: Evidence from UK Biobank

BACKGROUND & AIMS

There is evidence that long-term heavy coffee consumption may adversely affect individuals' cardiovascular disease (CVD) risk. As hyperlipidemia is a well-established contributor to CVD risk, we investigated the association between habitual coffee intake and plasma lipid profile.

METHODS

We used data from up to 362,571 UK Biobank participants to examine phenotypic associations between self-reported coffee intake and plasma lipid profiles, including low-density-lipoproteins cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (total-C), triglycerides, and apolipoproteins A1 and B (ApoA1 and ApoB). Mendelian randomization (MR) analysis using genetically instrumented coffee intake was used to interrogate the causal nature of coffee-lipid associations.

RESULTS

We observed a positive dose-dependent association between self-reported coffee intake and plasma concentration of LDL-C, ApoB and total-C, with the highest lipid levels seen among participants reported drinking >6 cups/day (P_{linear trend}≤ 3.24E-55 for all). Consistently, in MR analyses using genetically instrumented coffee intake one cup higher coffee intake was associated with a 0.07 mmol/L (95% CI 0.03 to 0.12), 0.02 g/L (95% CI 0.01 to 0.03), and 0.09 mmol/L (95% CI 0.04 to 0.14) increase in plasma concentration of LDL-C, ApoB, and total-C, respectively.

CONCLUSIONS

Our phenotypic and genetic analyses suggest that long-term heavy coffee consumption may lead to unfavourable lipid profile, which could potentially increase individuals' risk for CVD. These findings may have clinical relevance for people with elevated LDL cholesterol.

Tissue-Specific 1H-NMR Metabolomic Profiling in Mice with Adenine-Induced Chronic Kidney Disease

Chronic kidney disease (CKD) results in the impaired filtration of metabolites, which may be toxic or harmful to organs/tissues. The objective of this study was to perform unbiased ¹H nuclear magnetic resonance (NMR)-based metabolomics profiling of tissues from mice with CKD. Five-month-old male C57BL6J mice were placed on either a casein control diet or adenine-supplemented diet to induce CKD for 24 weeks. CKD was confirmed by significant increases in blood urea nitrogen (24.1 ± 7.7 vs. 105.3 ± 18.3 mg/dL, p < 0.0001) in adenine-fed mice. Following this chronic adenine diet, the kidney, heart, liver, and quadriceps muscles were rapidly dissected; snap-frozen in liquid nitrogen; and the metabolites were extracted. Metabolomic profiling coupled with multivariate analyses confirm clear separation in both aqueous and organic phases between control and CKD mice. Severe energetic stress and apparent impaired mitochondrial metabolism were observed in CKD kidneys evidenced by the depletion of ATP and NAD⁺, along with significant alterations in tricarboxylic acid (TCA) cycle intermediates. Altered amino acid metabolism was observed in all tissues, although significant differences in specific amino acids varied across tissue types. Taken together, this study provides a metabolomics fingerprint of multiple tissues from mice with and without severe CKD induced by chronic adenine feeding.

Relationship between serum lipid concentrations and impaired renal function in patients with chronic kidney disease: the Fukuoka Kidney Disease Registry Study

BACKGROUND

Patients with chronic kidney disease (CKD) have a higher risk of atherosclerotic cardiovascular disease (ASCVD). Dyslipidemia has been established as a risk factor for ASCVD. In the present study, we aimed to determine the prevalence of dyslipidemia at each stage of CKD.

METHODS

We conducted a cross-sectional study among 4476 patients registered in the Fukuoka Kidney Disease Registry Study, a Japanese prospective cohort study in patients with non-dialysis-dependent CKD. Outcomes were the prevalence of hyper-low-density lipoprotein (LDL) cholesterolemia, hyper-non-high-density lipoprotein (non-HDL) cholesterolemia, hypertriglyceridemia, and hypo-high-density lipoprotein (hypo-HDL) cholesterolemia at each stage of CKD. We analyzed the relationships between CKD stage and the prevalence of dyslipidemia using logistic regression models.

RESULTS

Patients in the advanced stages of CKD were more likely to have hypertriglyceridemia [OR 2.16 (95% CI 1.03-4.56), OR 2.24 (95% CI 1.04-4.84), OR 2.62 (95% CI 1.19-5.78), and OR 2.47 (95% CI 1.04-5.88) for CKD stages G3a, G3b, G4, and G5, respectively] and hypo-HDL-cholesterolemia [OR 2.66 (95% CI 1.21-5.82), OR 3.10 (95% CI 1.38-6.95), OR 2.86 (95% CI 1.25-6.53), and OR 3.30 (95% CI 1.35-8.10) for CKD stages G3a, G3b, G4, and G5, respectively] as compared with patients in CKD stage G1. The prevalence of hyper-LDL-cholesterolemia and hyper-non-HDL-cholesterolemia was not related to CKD stage.

CONCLUSION

Patients with advanced CKD stages are more likely to have hypertriglyceridemia and hypo-HDL-cholesterolemia than those in early stages. This type of lipid profile may represent a risk factor for ASCVD in patients with CKD.

The influence of the prebiotic gum acacia on the intestinal microbiome composition in rats with experimental chronic kidney disease

Chronic kidney disease (CKD) is a globally common and important disease and there are evidence for a bidirectional relationship between microbiota and CKD. The aim of the study was to examine the influence of prebiotic - gum acacia (GA) on the intestinal microbiota in rats with adenine-induced CKD. Animals were randomly distributed into four equal groups (n = 6): control, adenine, GA and adenine + GA groups. CKD was induced by adenine (0.75% w/w) given in the diet daily for four weeks, and GA was administered in drinking water at a concentration of 15% w/v. The 16s rRNA analysis was performed on Illumina Miseq targeting V3-V4 region to characterize microbial composition. The abundance of Actinobacteria, Proteobacteria, Tenericutes and Verrucomicrobia bacteria was increased in adenine-induced CKD, and GA treatment successfully reversed those levels. Interestingly, alpha and beta diversity index were both reduced with GA treatment in rats with CKD. Short chain fatty acids (SCFAs) measurement and PICRUSt analysis have shown that GA treatment completely restored the depleted butyrate level and various perturbated functional pathways, respectively, in CKD rats. Taking together, our results suggest that GA supplementation has a beneficial role in treating CKD, through an increased production of butyrate, as well as its anti-inflammatory, antioxidant capacity and anti-nitrosative properties.

Cross-sectional study of diabetes kidney disease in the Eastern Cape, South Africa

Diabetes mellitus (DM) is an independent risk factor for the development of kidney disease. This study assesses the prevalence and determinants of asymptomatic kidney disease in individuals with DM attending health facilities in OR Tambo district, Eastern Cape, South Africa.In this cross-sectional analysis, medical data of 327 individuals receiving care for DM in primary health care centers in OR Tambo district, Eastern Cape between June and November 2013 were reviewed. Significant kidney disease was defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m in accordance with the guidelines of the Society of Endocrinology, Metabolism and Diabetes of South Africa (2017).One-quarter of the 327 participants (n = 80) had significant kidney disease. Female sex [odds ratio (OR) = 5.2; 95% confidence interval (95% CI) 1.2-23.5], never used alcohol (OR = 13.4; 95% CI 2.5-72.1), hypertension (OR = 16.2; 95% CI 2.0-130.0), triglyceride (TG)/high-density lipoprotein (HDL) ratio (OR = 1.2; 95% CI 1.0-1.5), current smoker (OR = 1127.9; 95% CI 162.9-7808.9), former smoker (OR = 13.3; 95% CI 4.1-41.4), and longer duration of diabetes (OR = 4.6; 95% CI 1.6-13.0) were the independent determinants of significant kidney disease among the participants. A significant dose--effect relationship exists between renal disease and smoking status (P < .0001), duration of DM (P < .001), glycemic status (P = .025), and body mass index (P = .003).There is a high rate of undiagnosed kidney disease in this setting, which was independently associated with female sex and presence of other cardiovascular risk factors. Strategic interventions targeting screening and monitoring of renal functions in individuals with DM are urgently needed in this region.

Association of tubular solute clearances with the glomerular filtration rate and complications of chronic kidney disease: the Chronic Renal Insufficiency Cohort study

BACKGROUND

The secretion of organic solutes by the proximal tubules is an essential intrinsic kidney function. The degree to which secretory solute clearance corresponds with the glomerular filtration rate (GFR) and potential metabolic implications of net secretory clearance are largely unknown.

METHODS

We evaluated 1240 participants with chronic kidney disease (CKD) from the multicenter Chronic Renal Insufficiency Cohort (CRIC) Study. We used targeted mass-spectrometry to quantify candidate secretory solutes in paired 24-h urine and plasma samples. CRIC study personnel measured GFR using 125I-iothalamate clearance (iGFR). We used correlation and linear regression to determine cross-sectional associations of secretory clearances with iGFR and common metabolic complications of CKD.

RESULTS

Correlations between iGFR and secretory solute clearances ranged from ρ  = +0.30 for hippurate to ρ = +0.58 for kynurenic acid. Lower net clearances of most secretory solutes were associated with higher serum concentrations of parathyroid hormone (PTH), triglycerides and uric acid. Each 50% lower kynurenic acid clearance was associated with a 21% higher serum PTH concentration [95% confidence interval (CI) 15-26%] and a 10% higher serum triglyceride concentration (95% CI 5-16%) after adjustment for iGFR, albuminuria and other potential confounders. Secretory solute clearances were not associated with statistically or clinically meaningful differences in serum calcium, phosphate, hemoglobin or bicarbonate concentrations.

CONCLUSIONS

Tubular secretory clearances are modestly correlated with measured GFR among adult patients with CKD. Lower net secretory clearances are associated with selected metabolic complications independent of GFR and albuminuria, suggesting potential clinical and biological relevance.

Oxidative Stress in ESRD Patients on Dialysis and the Risk of Cardiovascular Diseases

Chronic kidney disease is highly prevalent worldwide. The decline of renal function is associated with inadequate removal of a variety of uremic toxins that exert detrimental effects on cells functioning, thus affecting the cardiovascular system. The occurrence of cardiovascular aberrations in CKD is related to the impact of traditional risk factors and non-traditional CKD-associated risk factors, including anemia; inflammation; oxidative stress; the presence of some uremic toxins; and factors related to the type, frequency of dialysis and the composition of dialysis fluid. Cardiovascular diseases are the most frequent cause for the deaths of patients with all stages of renal failure. The kidney is one of the vital sources of antioxidant enzymes, therefore, the impairment of this organ is associated with decreased levels of these enzymes as well as increased levels of pro-oxidants. Uremic toxins have been shown to play a vital role in the onset of oxidative stress. Hemodialysis itself also enhances oxidative stress. Elevated oxidative stress has been demonstrated to be strictly related to kidney and cardiac damage as it aggravates kidney dysfunction and induces cardiac hypertrophy. Antioxidant therapies may prove to be beneficial since they can decrease oxidative stress, reduce uremic cardiovascular toxicity and improve survival.

Gestational Diabetes Type 2: Variation in High-Density Lipoproteins Composition and Function

Aims: Class A2 gestational diabetes mellitus (GDMA2) has short- and long-term effects on the mother and child. These may include abnormalities of placentation, damage to endothelial cells and cardiovascular disease. This research investigated the function and composition of high-density lipoproteins (HDL) among women with GDMA2 and their fetuses. Methods: Thirty pregnant women were recruited during admission for delivery. The function and expression of HDL, paraoxonase1 (PON1) and apolipoprotein A1 (APOA1) in the blood samples and the placental tissue were evaluated. The effect of HDL on migration of endothelial cells was measured in vitro. Results: Compared to normal pregnancy (NP), APOA1 in the maternal plasma of women with GDMA2 was decreased. More APOA1 and PON1 were released from HDL of women with GDMA2, compared to NP. Placental APOA1 and PON1 were decreased in GDMA2. For endothelial cells stimulated with TNFα, HDL cell migration was decreased when cells were evaluated with NP-HDL, as compared to GDMA2-HDL. Conclusions: GDMA2 affects the composition and function of HDL in plasma. Changes in HDL commonly seen in GDMA2 were observed in maternal and placental samples, but not in cord samples. These results might indicate a placental role in protecting the fetus by preserving the components and functions of HDL and require further investigation.

Chronic Kidney Disease as Oxidative Stress- and Inflammatory-Mediated Cardiovascular Disease

Generating reactive oxygen species (ROS) is necessary for both physiology and pathology. An imbalance between endogenous oxidants and antioxidants causes oxidative stress, contributing to vascular dysfunction. The ROS-induced activation of transcription factors and proinflammatory genes increases inflammation. This phenomenon is of crucial importance in patients with chronic kidney disease (CKD), because atherosclerosis is one of the critical factors of their cardiovascular disease (CVD) and increased mortality. The effect of ROS disrupts the excretory function of each section of the nephron. It prevents the maintenance of intra-systemic homeostasis and leads to the accumulation of metabolic products. Renal regulatory mechanisms, such as tubular glomerular feedback, myogenic reflex in the supplying arteriole, and the renin–angiotensin–aldosterone system, are also affected. It makes it impossible for the kidney to compensate for water–electrolyte and acid–base disturbances, which progress further in the mechanism of positive feedback, leading to a further intensification of oxidative stress. As a result, the progression of CKD is observed, with a spectrum of complications such as malnutrition, calcium phosphate abnormalities, atherosclerosis, and anemia. This review aimed to show the role of oxidative stress and inflammation in renal impairment, with a particular emphasis on its influence on the most common disturbances that accompany CKD.

There is a U shaped association between non high density lipoprotein cholesterol with overall and cardiovascular mortality in chronic kidney disease stage 3-5

Dyslipidemia is common in patients with chronic kidney disease (CKD), however the relationship between dyslipidemia and mortality in patients with moderate to severe CKD remains controversial. Non-high-density lipoprotein (HDL) cholesterol has been reported to be a more accurate predictor of clinical outcomes than conventional lipid measurements. Hence, the aim of this study was to investigate associations between non-HDL cholesterol and the risk of overall and cardiovascular mortality in patients with CKD stage 3–5. We enrolled 429 pre-dialysis patients with stage 3 to 5 CKD from May 2006 to January 2010. The patients were divided into four groups according to quartiles of non-HDL cholesterol. The patients were followed until death or until January 2020. During a median 11.6 years of follow-up, there were 78 (18.2%) deaths overall and 32 (7.5%) cardiovascular deaths. In adjusted models, the patients in quartile 1 (hazard ratio [HR] 3.368; 95% confidence interval [CI] 1.388–8.176; p = 0.007), quartile 3 (HR 3.666; 95% CI 1.486–9.044; p = 0.005), and quartile 4 (HR 2.868; 95% CI 1.136–7.240; p = 0.026) of non-HDL cholesterol had a higher risk of overall mortality (vs. quartile 2). In addition, the patients in quartile 1 (HR 19.503; 95% CI 2.185–174.0925 p = 0.008), quartile 3 (HR 28.702; 95% CI 2.990–275.559; p = 0.004), and quartile 4 (HR 11.136; 95% CI 1.126–110.108; p = 0.039) had a higher risk of cardiovascular mortality (vs. quartile 2). Our study showed a U-shaped relationship between non-HDL cholesterol and the risk of overall and cardiovascular mortality in patients with CKD stage 3–5. Assessing non-HDL cholesterol may help to identify subjects at high-risk of adverse outcomes.

Progress and prospects of biological approaches targeting PCSK9 for cholesterol-lowering, from molecular mechanism to clinical efficacy

INTRODUCTION

Cardiovascular disorders are one of the leading causes of mortality and morbidity worldwide. Recent advances showed a promising role of proprotein convertase subtilisin/kexin type 9 (PCSK9) as a critical player in regulating plasma LDL levels and lipid metabolism.

AREAS COVERED

This review addresses the molecular functions of PCSK9 with a vision on the clinical progress of utilizing monoclonal antibodies and other biological approaches to block PCSK9 activity. The successful clinical trials with monoclonal antibodies are reviewed. Recent advances in (pre)clinical trials of other biological approaches, such as small interfering RNAs, are also discussed.

EXPERT OPINION

Discovery of PCSK9 and clinical use of its inhibitors to manage lipid metabolism is a step forward in hypolipidaemic therapy. A better understanding of the molecular activity of PCSK9 can help to identify new approaches in the inhibition of PCSK9 expression/activity. Whether if PCSK9 plays a role in other cardiometabolic conditions may provide grounds for further development of therapies.

Chronic kidney disease as a cardiovascular risk factor

: Chronic kidney disease (CKD) is a public health threat with impact in cardiovascular risk. All forms of cardiovascular disease and mortality are more common in CKD. Treatment of cardiovascular risk factors, hypertension, dyslipidemia and diabetes is essential for cardiovascular and kidney protection. CKD is a marker of high or very high cardiovascular risk and its presence require early treatment and specific goals. Lifestyle is a pivotal factor, stopping smoking, reducing weight in the overweight or obese, starting regular physical exercise and healthy dietary pattern are recommended. Office BP should be lowered towards 130/80 mmHg or even lower if tolerated with sodium restriction and single pill combination, including angiotensin system blocker. Out-of-office BP monitoring, mainly 24-h assessment, is recommended. Diabetes requires treatment from the moment of diagnosis, but prediabetes benefits with lifestyle changes and metformin in patients stage 2 and 3a. iSGLT2 and GLP-1RA are initially recommended in T2D patients with high or very high cardiovascular risk. Concerning dyslipidemia, for patients in stage 4, LDL-C 55 mg/dl or less (1.4 mmol/l) and an LDL-C reduction of 50% or less from baseline is recommended. In stage 3, LDL-C goal is 70 mg/dl or less (1.8 mmol/l) and an LDL-C. reduction of at least 50% from baseline. Statins are the lipid-lowering therapy of choice with or without ezetimibe. Higher doses of statins are required as GFR declines. Available evidence suggests that combined PCSK9 inhibitors with maximally tolerated dose of statins may have an emerging role in treatment of dyslipidemia in CKD patients.

A Review of Efforts to Improve Lipid Stability during Sample Preparation and Standardization Efforts to Ensure Accuracy in the Reporting of Lipid Measurements

Lipidomics is a rapidly growing field, fueled by developments in analytical instrumentation and bioinformatics. To date, most researchers and industries have employed their own lipidomics workflows without a consensus on best practices. Without a community-wide consensus on best practices for the prevention of lipid degradation and transformations through sample collection and analysis, it is difficult to assess the quality of lipidomics data and hence trust results. Clinical studies often rely on samples being stored for weeks or months until they are analyzed, but inappropriate sampling techniques, storage temperatures, and analytical protocols can result in the degradation of complex lipids and the generation of oxidized or hydrolyzed metabolite artifacts. While best practices for lipid stability are sample dependent, it is generally recommended that strategies during sample preparation capable of quenching enzymatic activity and preventing oxidation should be considered. In addition, after sample preparation, lipid extracts should be stored in organic solvents with antioxidants at -20 °C or lower in an airtight container without exposure to light or oxygen. This will reduce or eliminate sublimation, and chemically and physically induced molecular transformations such as oxidation, enzymatic transformation, and photon/heat-induced degradation. This review explores the available literature on lipid stability, with a particular focus on human health and/or clinical lipidomic applications. Specifically, this includes a description of known mechanisms of lipid degradation, strategies, and considerations for lipid storage, as well as current efforts for standardization and quality insurance of protocols.

Lipid profiles and risk of major adverse cardiovascular events in CKD and diabetes: A nationwide population-based study

The association of lipid parameters with cardiovascular outcomes and the impact of kidney function on this association have not been thoroughly evaluated in chronic kidney disease (CKD) patients with diabetes. We reviewed the National Health Insurance Database of Korea, containing the data of 10,505,818 subjects who received routine check-ups in 2009. We analyzed the association of lipid profile parameters with major adverse cardiovascular events (MACEs) risk and all-cause mortality in a nationally representative cohort of 51,757 lipid-lowering medication-naïve patients who had CKD and diabetes. Advanced CKD patients with eGFR <30 mL/min/1.73 m² (n = 10,775) had lower serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c) but higher non-HDL-c levels and triglyceride (TG) to HDL-c ratios. There was a positive linear association between serum LDL-c and MACE risk in both early and advanced CKD patients (P <0.001 for trend), except for the category of LDL-c 30–49 mg/dL in extremely low LDL-c subgroup analyses. A U-shaped relationship was observed between serum LDL-c and all-cause mortality (the 4^th and 8^th octile groups; lowest hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.87–1.05 and highest HR 1.14, 95% CI 1.04–1.26, respectively). A similar pattern remained in both early and advanced CKD patients. The TG/HDL-c ratio categories showed a positive linear association for MACE risk in early CKD (P <0.001 for trend), but this correlation disappeared in advanced CKD patients. There was no correlation between the serum TG/HDL-c ratio and all-cause mortality in the study patients. The LDL-c level predicted the risk for MACEs and all-cause mortality in both early and advanced CKD patients with diabetes, although the patterns of the association differed from each other. However, the TG/HDL-c ratio categories could not predict the risk for either MACEs or all-cause mortality in advanced CKD patients with diabetes, except that the TG/HDL-c ratio predicted MACE risk in early CKD patients with diabetes.

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

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

High-throughput liquid chromatography mass-spectrometry-driven lipidomics discover metabolic biomarkers and pathways as promising targets to reveal the therapeutic effects of the Shenqi pill

Lipidomics, a branch of metabonomics, could provide a powerful technique for discovery of lipid molecules to reveal disease status and drug efficacy.

"Lipidomics": Mass spectrometric and chemometric analyses of lipids

Lipids are ubiquitous in the human organism and play essential roles as components of cell membranes and hormones, for energy storage or as mediators of cell signaling pathways. As crucial mediators of the human metabolism, lipids are also involved in metabolic diseases, cardiovascular and renal diseases, cancer and/or hepatological and neurological disorders. With rapidly growing evidence supporting the impact of lipids on both the genesis and progression of these diseases as well as patient wellbeing, the characterization of the human lipidome has gained high interest and importance in life sciences and clinical diagnostics within the last 15 years. This is mostly due to technically advanced molecular identification and quantification methods, mainly based on mass spectrometry. Mass spectrometry has become one of the most powerful tools for the identification of lipids. New lipidic mediators or biomarkers of diseases can be analysed by state-of-the art mass spectrometry techniques supported by sophisticated bioinformatics and biostatistics. The lipidomic approach has developed dramatically in the realm of life sciences and clinical diagnostics due to the available mass spectrometric methods and in particular due to the adaptation of biostatistical methods in recent years. Therefore, the current knowledge of lipid extraction methods, mass-spectrometric approaches, biostatistical data analysis, including workflows for the interpretation of lipidomic high-throughput data, are reviewed in this manuscript.

Cardiovascular Risk Reduction in High-Risk Pediatric Patients: A Scientific Statement From the American Heart Association

This scientific statement presents considerations for clinical management regarding the assessment and risk reduction of select pediatric populations at high risk for premature cardiovascular disease, including acquired arteriosclerosis or atherosclerosis. For each topic, the evidence for accelerated acquired coronary artery disease and stroke in childhood and adolescence and the evidence for benefit of interventions in youth will be reviewed. Children and adolescents may be at higher risk for cardiovascular disease because of significant atherosclerotic or arteriosclerotic risk factors, high-risk conditions that promote atherosclerosis, or coronary artery or other cardiac or vascular abnormalities that make the individual more vulnerable to the adverse effects of traditional cardiovascular risk factors. Existing scientific statements and guidelines will be referenced when applicable, and suggestions for risk identification and reduction specific to each setting will be described. This statement is directed toward pediatric cardiologists, primary care providers, and subspecialists who provide clinical care for these young patients. The focus will be on management and justification for management, minimizing information on pathophysiology and epidemiology.

Chronic treatment of curcumin improves hepatic lipid metabolism and alleviates the renal damage in adenine-induced chronic kidney disease in Sprague-Dawley rats

Background

Chronic kidney disease (CKD), including nephrotic syndrome, is a major cause of cardiovascular morbidity and mortality. The literature indicates that CKD is associated with profound lipid disorders due to the dysregulation of lipoprotein metabolism which progresses kidney disease. The objective of this study is to evaluate the protective effects of curcumin on dyslipidaemia associated with adenine-induced chronic kidney disease in rats.

Methods

Male SD rats (n = 29) were divided into 5 groups for 24 days: normal control (n = 5, normal diet), CKD control (n = 6, 0.75% w/w adenine-supplemented diet), CUR 50 (n = 6, 50 mg/kg/day curcumin + 0.75% w/w adenine-supplemented diet), CUR 100 (n = 6, 100 mg/kg/day curcumin + 0.75% w/w adenine-supplemented diet), and CUR 150 (n = 6, 150 mg/kg/day curcumin + 0.75% w/w adenine-supplemented diet). The serum and tissue lipid profile, as well as the kidney function test, were measured using commercial diagnostic kits.

Results

The marked rise in total cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, triglycerides and free fatty acids in serum, as well as hepatic cholesterol, triglyceride and free fatty acids of CKD control rats were significantly protected by curcumin co-treatment (at the dose of 50, 100 and 150 mg/kg). Furthermore, curcumin significantly increased the serum high-density lipoprotein (HDL) cholesterol compared to the CKD control rats but did not attenuate the CKD-induced weight retardation. Mathematical computational analysis revealed that curcumin significantly reduced indicators for the risk of atherosclerotic lesions (atherogenic index) and coronary atherogenesis (coronary risk index). In addition, curcumin improved kidney function as shown by the reduction in proteinuria and improvement in creatinine clearance.

Conclusion

The results provide new scientific evidence for the use of curcumin in CKD-associated dyslipidaemia and substantiates the traditional use of curcumin in preventing kidney damage.

Cholesterol Disturbances and the Role of Proper Nutrition in CKD Patients

Chronic kidney disease (CKD) is a widespread disease with increasing prevalence in the modern society. Lipid disturbances are common in this group of patients. In most patients with CKD atherogenic dyslipidemia is observed. Dyslipidemia in patients with renal diseases increases the risk of cardiovascular diseases and it accelerates the progression of chronic kidney disease to its end stage. The amelioration of dyslipidemia and the lowering of oxidative stress, inflammatory processes, insulin sensitivity and remnant lipoproteins levels may lead to the reduction in cardiovascular burden. Nutritional interventions can strengthen the beneficial effect of treatment and they play an important role in the preservation of overall well-being of the patients with CKD since the aim of appropriate diet is to reduce the risk of cardiovascular events, prevent malnutrition, and hamper the progression of kidney disease. The management of dyslipidemia, regardless of the presence of chronic kidney disease, should be initiated by the introduction of therapeutic lifestyle changes. The introduction of diet change was shown to exert beneficial effect on the lipid level lowering that reaches beyond pharmacological therapy. Currently available evidence give the impression that data on dietary interventions in CKD patients is not sufficient to make any clinical practice guidelines and is of low quality.

Efficacy and Safety of Pemafibrate, a Novel Selective Peroxisome Proliferator-Activated Receptor α Modulator (SPPARMα): Pooled Analysis of Phase 2 and 3 Studies in Dyslipidemic Patients with or without Statin Combination

Hypertriglyceridemia has emerged as an independent risk factor for cardiovascular events, despite low-density lipoprotein-cholesterol (LDL-C) well-controlled with statins. We pooled data from the first 12 weeks of six randomized double-blind placebo-controlled studies of pemafibrate in Japan and investigated its efficacy and safety with and without statins, particularly focusing on patients with renal dysfunction. Subjects were 1253 patients (677 in the "with-statin" group and 576 in the "without-statin" group). At Week 12 (last observation carried forward), triglyceride (TG) was significantly reduced at all pemafibrate doses (0.1, 0.2, and 0.4 mg/day), both with and without statin, compared to placebo (p < 0.001 vs. placebo for all groups). In the "with-statin" group, the estimated percent change from baseline was -2.0% for placebo and -45.1%, -48.5%, and -50.0%, respectively, for the pemafibrate groups. Findings for both groups showed significant decreases in TG-rich lipoproteins and atherogenic lipid parameters compared to placebo. The incidence of adverse events was similar between the pemafibrate and placebo groups and was also similar for patients with and without renal dysfunction in the "with-statin" group. Pemafibrate lowered TG and improved atherogenic dyslipidemia without a significant increase in adverse events in comparison to the placebo, even among "with-statin" patients who had renal dysfunction.

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.

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

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

Anti-Oxidant in China: A Thirty-Year Journey

Anti-oxidant refers to such a kind of endogenous or exogenous compound that is able to retard or even prohibit in vivo or in vitro oxidation with only small amount being used. The study of anti-oxidants starts nearly 30 years ago, and the research on this topic in China almost begins simultaneously with that in the world. Gratifyingly, contributions on anti-oxidants from China researchers have rapidly increased in the recent decade as anti-oxidants have become a hot topic in biochemistry, pharmacology, food science, chemistry as well as other related disciplines. Anti-oxidants provide a specific viewpoint for clarifying pharmacological effects of Chinese medicinal herbs. For example, as a traditional Chinese medicinal herb, Panax ginseng C. A. Meyer is found to be a natural anti-oxidant resource. Meanwhile, some signaling pathways such as nuclear factor-[Formula: see text]B (NF-[Formula: see text]B), nuclear factor erythroid 2 related factor 2 (Nrf2), and Kelch-like ECH associated protein 1 (Keap1) are regarded to play an important role in anti-oxidant responses. These findings provide a substantial basis for understanding the pharmacological behaviors of Chinese medicinal herbs in view of regulating the aforementioned signaling pathways. Moreover, inhibition of reactive oxygen species (ROS) by supplementation of anti-oxidant becomes a popularly accepted idea in keeping health and treating diseases. Isolations of antio-xidative ingredients from medicinal herbs and foods lead to set up a large range of anti-oxidative compound libraries, and intake of anti-oxidants from foods may be the most efficient way for supplementing exogenous anti-oxidants. On the other hand, designing anti-oxidants with novel structures motivates organic and medicinal chemists to explore the structure–activity relationship, and then, to find novel structural features with anti-oxidative properties. Therefore, it is reasonable to believe that China researchers will donate more endeavors to obtain more achievements on anti-oxidants in the future.

Endothelin Receptor Antagonism Improves Lipid Profiles and Lowers PCSK9 (Proprotein Convertase Subtilisin/Kexin Type 9) in Patients With Chronic Kidney Disease

Dyslipidemia is common in chronic kidney disease (CKD). Despite statins, many patients fail to adequately lower lipids and remain at increased risk of cardiovascular disease. Selective ET_A (endothelin-A) receptor antagonists reduce cardiovascular disease risk factors. Preclinical data suggest that ET_A antagonism has beneficial effects on circulating lipids. We assessed the effects of selective ET_A antagonism on circulating lipids and PCSK9 (proprotein convertase subtilisin/kexin type 9) in CKD. This was a secondary analysis of a fully randomized, double-blind, 3-phase crossover study. Twenty-seven subjects with predialysis CKD on optimal cardio- and renoprotective treatment were randomly assigned to receive 6 weeks dosing with placebo, the selective ET_A receptor antagonist, sitaxentan, or long-acting nifedipine. We measured circulating lipids and PCSK9 at baseline and then after 3 and 6 weeks. Baseline lipids and PCSK9 did not differ before each study phase. Whereas placebo and nifedipine had no effect on lipids, 6 weeks of ET_A antagonism significantly reduced total (-11±1%) and low-density lipoprotein-associated (-20±3%) cholesterol, lipoprotein (a) (-16±2%) and triglycerides (-20±4%); high-density lipoprotein-associated cholesterol increased (+14±2%), P<0.05 versus baseline for all. Additionally, ET_A receptor antagonism, but neither placebo nor nifedipine, reduced circulating PCSK9 (-19±2%; P<0.001 versus baseline; P<0.05 versus nifedipine and placebo). These effects were independent of statin use and changes in blood pressure or proteinuria. Selective ET_A antagonism improves lipid profiles in optimally-managed patients with CKD, effects that may occur through a reduction in circulating PCSK9. ET_A receptor antagonism offers a potentially novel strategy to reduce cardiovascular disease risk in CKD. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT00810732.

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

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

Dual-modified natural high density lipoprotein particles for systemic glioma-targeting drug delivery

Therapeutic outcome for the treatment of glioma was often limited due to the two barriers involved: the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB). Therefore, the development of nanocarriers that possess both BBB and BBTB permeability and glioma-targeting ability is of great importance for the chemotherapy of glioma. New frontiers in nanomedicine are advancing the research of new biomaterials. Here we constructed a natural high-density lipoprotein particle (HDL)-based drug delivery system with the dual-modification of T7 and ^dA7R peptide ligand (T7/^dA7R-HDL) to achieve the above goals. HDL, the smallest lipoprotein, plays a biological role and is highly suitable as a platform for delivering imaging and therapeutic agents. T7 is a seven-peptide ligand of transferrin receptors (TfR) capable of circumventing the BBB and then targeting glioma. ^dA7R is a d-peptide ligand of vascular endothelial growth factor receptor 2 (VEGFR 2) overexpressed on angiogenesis, presenting excellent glioma-homing property. 10-Hydroxycamptothecin (HCPT), a hydrophobic anti-cancer drug, was used as the model drug in this study. By combining the dual-targeting delivery effect, the dual-modified HDL displayed higher glioma localization than that of single ligand-modified HDL or free HCPT. After loading with HCPT, T7/^dA7R-HDL showed the most favorable anti-glioma effect in vivo. These results demonstrated that the dual-targeting natural nanocarriers strategy provides a potential method for improving brain drug delivery and anti-glioma treatment efficacy.

Longitudinal lipid trends and adverse outcomes in patients with CKD: a 13-year observational cohort study

Studies on the effects of longitudinal lipid trajectories on end-stage renal disease (ESRD) development and deaths among patients with chronic kidney disease (CKD) are limited. We conducted a registry-based prospective study using data from a 13-year multidisciplinary pre-ESRD care program. The final study population comprised 4,647 patients with CKD. Using group-based trajectory modeling, we dichotomized longitudinal trajectories of total cholesterol (T-CHO), triglyceride (TG), LDL cholesterol (LDL-C), and HDL cholesterol (HDL-C). Time to ESRD or death was analyzed using multiple Cox regression. At baseline, higher levels of T-CHO and LDL-C were associated with rapid progression to ESRD, whereas only HDL-C was positively associated with all-cause mortality [adjusted hazard ratio (HR), 1.20; 95% CI, 1.06-1.36; P-value, 0.005]. Compared with those with a normal T-CHO trajectory, the fully adjusted HR of patients with a high T-CHO trajectory for ESRD risk was 1.21 (P-value, 0.019). Subgroup analysis showed that a high TG trajectory was associated with a 49% increase in mortality risk in CKD patients without diabetes (P-value for interaction, 0.012). In contrast to what was observed based on baseline HDL-C, patients with a trajectory of frequent hypo-HDL cholesterolemia had higher risk of all-cause mortality (adjusted HR, 1.53; P-value, 0.014). Thus, only T-CHO, both at baseline and over the longitudinal course, demonstrated a significant potential risk of incident ESRD. The inconsistency in the observed directions of association between baseline levels and longitudinal trajectories of HDL-C warrants further research to unveil specific pathogenic mechanisms underlying the HDL-C metabolism in patients with CKD.

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.

Alteration of HDL Protein Composition with Hemodialysis Initiation

BACKGROUND AND OBJECTIVES

HDL particles obtained from patients on chronic hemodialysis exhibit lower cholesterol efflux capacity and are enriched in inflammatory proteins compared with those in healthy individuals. Observed alterations in HDL proteins could be due to effects of CKD, but also may be influenced by the hemodialysis procedure, which stimulates proinflammatory and prothrombotic pathways.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We compared HDL-associated proteins in 143 participants who initiated hemodialysis within the previous year with those of 110 participants with advanced CKD from the Hemodialysis Fistula Maturation Study. We quantified concentrations of 38 HDL-associated proteins relative to total HDL protein using targeted mass spectrometry assays that included a stable isotope-labeled internal standard. We used linear regression to compare the relative abundances of HDL-associated proteins after adjustment and required a false discovery rate q value ≤10% to control for multiple testing. We further assessed the association between hemodialysis initiation and cholesterol efflux capacity in a subset of 80 participants.

RESULTS

After adjustment for demographics, comorbidities, and other clinical characteristics, eight HDL-associated proteins met the prespecified false discovery threshold for association. Recent hemodialysis initiation was associated with higher HDL-associated concentrations of serum amyloid A1, A2, and A4; hemoglobin-β; haptoglobin-related protein; cholesterylester transfer protein; phospholipid transfer protein; and apo E. The trend for participants recently initiating hemodialysis for lower cholesterol efflux capacity compared with individuals with advanced CKD did not reach statistical significance.

CONCLUSIONS

Compared with advanced CKD, hemodialysis initiation within the previous year is associated with higher concentrations of eight HDL proteins related to inflammation and lipid metabolism. Identified associations differ from those recently observed for nondialysis-requiring CKD. Hemodialysis initiation may further impair cholesterol efflux capacity. Further work is needed to clarify the clinical significance of the identified proteins with respect to cardiovascular risk.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_07_25_CJASNPodcast_18_8_W.mp3.

Effects of Low-Protein Diet on lipid and anthropometric profiles of patients with chronic kidney disease on conservative management

INTRODUCTION

Chronic Kidney disease (CKD) patients have a high prevalence of cardiovascular mortality, and among the risk factors are dyslipidemia and obesity, common findings in the early stages of CKD. The aim of this study was to evaluate the effects of low protein diet (LPD) on the lipid and anthropometric profile in non-dialysis CKD patients.

METHODS

Forty CKD patients were studied (20 men, 62.7 ± 15.2 years, glomerular filtration rate (GFR) 26.16 ± 9.4 mL/min/1.73m2). LPD (0.6g/kg/d) was prescribed for six months and, biochemical and anthropometric parameters like body mass index (BMI), waist circumference and body fat mass (assessed by dual X-ray absorptiometry - DXA) were evaluated before and after six months with LPD.

RESULTS

After six months of nutritional intervention, patients presented reduction on BMI (from 28.1 ± 5.6 to 27.0 ± 5.3 Kg/m2, p = 0.001), total cholesterol (from 199.7 ± 57.1 to 176.0 ± 43.6mg/dL, p = 0.0001), LDL (from 116.2 ± 48.1 to 97.4 ± 39.1 mg/dL, p = 0,001) and uric acid (from 6.8 ± 1.4 to 6.2 ± 1.3 mg/dL, p = 0.004). In addition, GFR values were increased from 26.2 ± 9.5 to 28.9 ± 12.7mL/min (p = 0.02). The energy, proteins, cholesterol and fiber intake were reduced significantly.

CONCLUSION

LPD prescribe to non-dialysis CKD patients for six months was able to improve some cardiovascular risk factors as overweight and plasma lipid profile, suggesting that LPD can be also an important tool for protection against cardiovascular diseases in these patients.

A Dipeptidyl Peptidase-4 Inhibitor, Teneligliptin, Decreases Plasma Triglyceride-Rich Lipoprotein Remnants in Diabetic Patients with Chronic Kidney Disease Undergoing Hemodialysis

Objective

A high plasma level of remnant-like particle cholesterol (RLP-C), which is equivalent to triglyceride-rich lipoprotein remnant, is an important coronary risk marker. RLP-C level is high, independent of other plasma lipids, in patients with chronic kidney disease (CKD) undergoing hemodialysis. The effect of teneligliptin, a dipeptidyl peptidase (DPP)-4 inhibitor, on plasma levels of RLP-C in patients with diabetes mellitus and CKD under hemodialysis was studied.

Methods

Teneligliptin 20 mg/day was administered to 15 patients with diabetes and CKD undergoing hemodialysis for 12 weeks. Ten patients with diabetes and CKD undergoing hemodialysis were allocated to the control group. Blood was sampled following a 12-h fast. Fasting plasma glucose (FPG), C-peptide, triglyceride, low-density lipoprotein (LDL)-cholesterol (C), high-density lipoprotein (HDL)-C, RLP-C, apolipoprotein (apo) B, oxidized LDL, lipoprotein lipase, and glycated hemoglobin (HbA1c) were measured.

Results

HbA1c decreased in the teneligliptin group but significantly increased in the control group. FPG and RLP-C significantly decreased in the teneligliptin group. Plasma lipoprotein-related parameters except RLP-C were not affected by teneligliptin treatment.

Conclusion

Teneligliptin treatment significantly reduced plasma levels of RLP-C, FPG, and HbA1c in patients with diabetes with CKD who are undergoing hemodialysis.

Lipid levels are inversely associated with infectious and all-cause mortality: international MONDO study results

Cardiovascular (CV) events are increased 36-fold in patients with end-stage renal disease. However, randomized controlled trials to lower LDL cholesterol (LDL-C) and serum total cholesterol (TC) have not shown significant mortality improvements. An inverse association of TC and LDL-C with all-cause and CV mortality has been observed in patients on chronic dialysis. Lipoproteins also may protect against infectious diseases. We used data from 37,250 patients in the international Monitoring Dialysis Outcomes (MONDO) database to evaluate the association between lipids and infection-related or CV mortality. The study began on the first day of lipid measurement and continued for up to 4 years. We applied Cox proportional models with time-varying covariates to study associations of LDL-C, HDL cholesterol (HDL-C), and triglycerides (TGs) with all-cause, CV, infectious, and other causes of death. Overall, 6,147 patients died (19.2% from CV, 13.2% from infection, and 67.6% from other causes). After multivariable adjustment, higher LDL-C, HDL-C, and TGs were independently associated with lower all-cause death risk. Neither LDL-C nor TGs were associated with CV death, and HDL-C was associated with lower CV risk. Higher LDL-C and HDL-C were associated with a lower risk of death from infection or other non-CV causes. LDL-C was associated with reduced all-cause and infectious, but not CV mortality, which resulted in the inverse association with all-cause mortality.

Serum ApoA4 levels predicted the progression of renal impairment in T2DM

BACKGROUND

Among multiple causes, diabetic nephropathy (DN) is the major underlying renal disease that leads to end-stage renal disease (ESRD), and early diagnosis can effectively prevent or delay the progression to ESRD. Therefore, the current study aimed to develop noninvasive, accurate detection markers.

MATERIALS & METHODS

For this study, 62 diabetes mellitus (DM) patients, 59 DN patients and 21 healthy controls (HCs) were recruited. All participants' serum samples were subjected to concavanalin (Con) A affinity chromatography, which utilizes glycoproteins to discover potential markers.

RESULTS

From nano LC-MS and Western blot analysis, apolipoprotein A-IV (ApoA4) was selected which featured a gradual, almost twofold increase in the order of HC, DM and DN. In the Con A-based ELISA, the DM group was 1.91-fold higher than the HC group, while the DN group was 2.56-fold higher than the HCs and 1.33-fold higher than the DM group. In addition, significant positive correlations were observed between ApoA4 and blood urea nitrogen levels and between ApoA4 and creatine levels, while significant negative correlations were seen between serum protein levels and between serum albumin levels in comparisons of DM and DN samples.

CONCLUSIONS

Serum Con A-bound ApoA4 levels were higher in the DM group than in HCs, and further increased in the DN group. Levels of ApoA4 were positively correlated with blood urea nitrogen and creatine, but negatively correlated with serum protein and albumin. This evidence supports serum Con A-bound ApoA4 as a circulating marker for predicting the progression of renal impairment in DM patients.

Structural analysis of a Petri net model of oxidative stress in atherosclerosis

Atherosclerosis is a complex process of gathering sub-endothelial plaques decreasing lumen of the blood vessels. This disorder affects people of all ages, but its progression is asymptomatic for many years. It is regulated by many typical and atypical factors including the immune system response, a chronic kidney disease, a diet rich in lipids, a local inflammatory process and a local oxidative stress that is here one of the key factors. In this study, a Petri net model of atherosclerosis regulation is presented. This model includes also some information about stoichiometric relationships between its components and covers all mentioned factors. For the model, a structural analysis based on invariants was made and biological conclusions are presented. Since the model contains inhibitor arcs, a heuristic method for analysis of such cases is presented. This method can be used to extend the concept of feasible t-invariants.

Disorders of Lipid Metabolism in Chronic Kidney Disease

Cardiovascular disease (CVD) is the leading cause of death in chronic kidney disease (CKD). One of the most important pathophysiological mechanisms for CVD in patients with CKD is the widespread and possibly accelerated formation of atherosclerotic plaques due to hyperlipidemia, uremic toxins, inflammation, oxidative stress, and endothelial dysfunction. Recent studies showed that the level of oxidized low-density lipoprotein cholesterol increases, and that high-­density lipoprotein cholesterol dysfunction occurs as kidney function declines and inflammation becomes more prevalent. In this review, we aimed to discuss the effect of kidney dysfunction, oxidative stress, and inflammation on lipid ­profile.

Palmitic Acid-Induced Podocyte Apoptosis via the Reactive Oxygen Species-Dependent Mitochondrial Pathway

BACKGROUND/AIMS

Chronic kidney disease (CKD) is often accompanied by hyperlipidemia, which accelerates progression of the disease. Podocyte injury can lead to dysfunction of the glomerular filtration barrier, which is associated with proteinuria, a risk marker for the progression of CKD. Our previous studies demonstrated that palmitic acid (PA) can induce podocyte apoptosis; however, the underlying mechanisms are unclear. In the present study, we investigated the specific molecular mechanisms of PA-induced apoptosis in cultured podocytes.

METHODS

We cultured mouse podocytes and treated them with PA. Then, cell viability was measured using the Cell Counting Kit-8 colorimetric assay, lipid uptake was assessed by Oil Red O staining and boron-dipyrromethene staining, apoptosis was measured by flow cytometry, mitochondrial injury was assessed by JC-1 staining and transmission electron microscopy, and mitochondrial production of reactive oxygen species (ROS) was evaluated by fluorescence microscopy using the MitoSOX Red reagent. The effects of PA on the mitochondria-mediated caspase activation pathway were investigated by examining the expression of caspase-8, cleaved caspase-9, cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), B-cell lymphoma 2 (Bcl-2), Bax, Bid, cytochrome c, and Fas-associated protein with death domain (FADD) using western blotting. The translocation of Bax and cytochrome c were detected by immunofluorescence.

RESULTS

PA treatment significantly increased lipid accumulation and induced podocyte apoptosis. We investigated whether the two primary apoptosis signaling pathways (death receptor-mediated pathway and mitochondria-mediated pathway) were involved in the execution of PA-induced podocyte apoptosis, and found that the levels of FADD, caspase-8, and Bid did not significantly change during this process. Meanwhile, PA treatment induced an increase in Bax protein expression and a decrease in Bcl-2 protein expression, with Bax translocation to the mitochondria. Furthermore, PA treatment induced mitochondrial impairment, and triggered the release of cytochrome c from the mitochondria to cytosol, with a concomitant dose-dependent increase in the levels of cleaved caspase-9, cleaved caspase-3, and PARP. Meanwhile, PA treatment increased mitochondrial production of ROS, and the mitochondria-targeted antioxidant mitoTEMPO significantly ameliorated PA-induced podocyte apoptosis.

CONCLUSION

Our findings indicated that PA induced caspase-dependent podocyte apoptosis through the mitochondrial pathway, and mitochondrial ROS production participated in this process, thus potentially contributing to podocyte injury.

HDL in CKD-The Devil Is in the Detail

The picture of HDL cholesterol (HDL-C) as the "good" cholesterol has eroded. This is even more surprising because there exists strong evidence that HDL-C is associated with cardiovascular disease (CVD) in the general population as well as in patients with impairment of kidney function and/or progression of CKD. However, drugs that dramatically increase HDL-C have mostly failed to decrease CVD events. Furthermore, genetic studies took the same line, as genetic variants that have a pronounced influence on HDL-C concentrations did not show an association with cardiovascular risk. For many, this was not surprising, given that an HDL particle is highly complex and carries >80 proteins and several hundred lipid species. Simply measuring cholesterol might not reflect the variety of biologic effects of heterogeneous HDL particles. Therefore, functional studies and the involvement of HDL components in the reverse cholesterol transport, including the cholesterol efflux capacity, have become a further focus of study during recent years. As also observed for other aspects, CKD populations behave differently compared with non-CKD populations. Although clear disturbances have been observed for the "functionality" of HDL particles in patients with CKD, this did not necessarily translate into clear-cut associations with outcomes.

A plasma proteomics method reveals links between ischemic stroke and MTHFR C677T genotype

Methylene Tetrahydrofolate Reductase (MTHFR) catalyzes the conversion of methylene tetrahydrofolate to methylte trahydrofolate. The 677th nucleotide of the MTHFR gene is often regarded as a risk factor of cardiovascular disease. Previous studies demonstrated an elevated risk of ischemic stroke with the MTHFR677TT genotype. In this study, we employed a plasma proteomics method to investigate the connection between the polymorphism of the target nucleotide and stroke. In total, 28 protein spots were differentially expressed between the two groups, and of which, 25 protein spots were up-regulated and 3 were down-regulated. Five randomly selected spots were successfully identified as Haptoglobin (HPT) and Transferrin (TRFE). A functional analysis indicated that most of the differential expressed proteins (DEPs) were related to the inflammatory immune response. A Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that these DEPs were involved in the complement cascade reaction. Meanwhile, protein-protein interactions (PPIs) analysis highlighted the novel association between the C677T MTHFR genotype and Vitamin D binding protein (DBP), which was confirmed by a molecular genetic analysis. The results suggested that the phenotype of the MTHFR might be associated with multiple proteins that have a synergistic effect, which might be related to the mechanism of ischemic stroke.