LCZ696 (Sacubitril/Valsartan), an Angiotensin-Receptor Neprilysin Inhibitor, Attenuates Cardiac Hypertrophy, Fibrosis, and Vasculopathy in a Rat Model of Chronic Kidney Disease.

BACKGROUND: Chronic kidney disease (CKD) is associated with cardiac hypertrophy, fibrosis, and increased risk of cardiovascular mortality. LCZ696 (sacubitril/valsartan) is a promising agent that has shown significant potential in treatment of heart failure. We hypothesized that LCZ696 is more effective than valsartan alone in the treatment of cardiovascular abnormalities associated with experimental CKD. METHODS AND RESULTS: Male Sprague-Dawley rats underwent 5/6 nephrectomy and were subsequently randomized to no treatment (CKD), 30 mg/kg valsartan (VAL), or 60 mg/kg LCZ696 (LCZ). After 8 weeks, cardiovascular parameters, including markers of inflammation, oxidative stress, mitochondrial abundance/function, hypertrophy, and fibrosis, were measured. Treatment with LCZ resulted in significant improvements in the heart-body weight ratio and serum concentrations of N-terminal pro-B-type natriuretic peptide and fibroblast growth factor 23 along with improvement of kidney function. In addition, LCZ ameliorated aortic fibrosis and cardiac hypertrophy and fibrosis, reduced markers of cardiac oxidative stress and inflammation, and improved indicators of mitochondrial mass/function. Although VAL also improved some of these indices, treatment with LCZ was more effective than VAL alone. CONCLUSIONS: CKD-associated cardiovascular abnormalities, including myocardial hypertrophy, fibrosis, inflammation, oxidative stress, and mitochondrial depletion/dysfunction, were more effectively attenuated by LCZ treatment than by VAL alone.

Niacin and progression of CKD.

Niacin is the oldest drug available for the treatment of dyslipidemia. It has been studied extensively and tested in clinical trials of atherosclerotic cardiovascular disease prevention and regression in the general population, but not specifically in patients with chronic kidney disease (CKD), who are at extremely high residual risk despite current therapy. Despite the current controversy about recent trials with niacin, including their limitations, there may be a place for this agent in select patients with CKD with dyslipidemia. Niacin has a favorable unique impact on factors affecting the rate of glomerular filtration rate decline, including high-density lipoprotein (HDL) particle number and function, triglyceride levels, oxidant stress, inflammation and endothelial function, and lowering of serum phosphorus levels by reducing dietary phosphorus absorption in the gastrointestinal tract. These effects may slow glomerular filtration rate decline and ultimately improve CKD outcomes and prevent cardiovascular risk. This review presents the clinically relevant concept that niacin holds significant potential as a renoprotective therapeutic agent. In addition, this review concludes that clinical investigations to assess the effect of niacin (in addition to aggressive low-density lipoprotein cholesterol lowering) on reduction of cardiovascular events in patients with CKD with very low HDL cholesterol (or those with identified dysfunctional HDL) and elevated triglyceride levels need to be considered seriously to address the high residual risk in this population.

Association of serum lipids with outcomes in Hispanic hemodialysis patients of the West versus East Coasts of the United States.

BACKGROUND: Paradoxical associations exist between serum lipid levels and mortality in patients on maintenance hemodialysis (MHD) including those of Hispanic origin. However, there are significant racial and ethnic variations in patients of 'Hispanic' background. We hypothesized that clinically meaningful differences existed in the association between lipids and survival in Hispanic MHD patients on the West versus East Coast. METHODS: We examined the survival impact of serum lipids in a 2-year cohort of 15,109 MHD patients of Hispanic origin being treated in California, Texas, representing the West versus New York, New Jersey and Florida representing the East Coast, using Cox models with various degrees of adjustments. RESULTS: The association of serum total and HDL cholesterol with mortality follows a U-shaped pattern in Hispanic patients residing in the West. This is in contrast to Hispanic patients in the East Coast whose survival seems to improve with increasing total and HDL cholesterol levels. Elevated serum LDL levels in Hispanic patients on the West Coast are associated with a significant increase in mortality, while this association is not observed in patients residing on the East Coast. CONCLUSIONS: Substantial differences exist in the association of serum lipids with mortality in MHD patients of Hispanic background depending on whether they reside on the West or East Coast of the United States. These geographical variances most likely reflect ethnic, racial and genetic distinctions, which are usually ignored. Future studies should take into account these critical variations in a population of patients who make up a significant portion of our society.

Therapeutic role of niacin in the prevention and regression of hepatic steatosis in rat model of nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD), a leading cause of liver damage, comprises a spectrum of liver abnormalities including the early fat deposition in the liver (hepatic steatosis) and advanced nonalcoholic steatohepatitis. Niacin decreases plasma triglycerides, but its effect on hepatic steatosis is elusive. To examine the effect of niacin on steatosis, rats were fed either a rodent normal chow, chow containing high fat (HF), or HF containing 0.5% or 1.0% niacin in the diet for 4 wk. For regression studies, rats were first fed the HF diet for 6 wk to induce hepatic steatosis and were then treated with niacin (0.5% in the diet) while on the HF diet for 6 wk. The findings indicated that inclusion of niacin at 0.5% and 1.0% doses in the HF diet significantly decreased liver fat content, liver weight, hepatic oxidative products, and prevented hepatic steatosis. Niacin treatment to rats with preexisting hepatic steatosis induced by the HF diet significantly regressed steatosis. Niacin had no effect on the mRNA expression of fatty acid synthesis or oxidation genes (including sterol-regulatory element-binding protein 1, acetyl-CoA carboxylase 1, fatty acid synthase, and carnitine palmitoyltransferase 1) but significantly inhibited mRNA levels, protein expression, and activity of diacylglycerol acyltrasferase 2, a key enzyme in triglyceride synthesis. These novel findings suggest that niacin effectively prevents and causes the regression of experimental hepatic steatosis. Approved niacin formulation(s) for other indications or niacin analogs may offer a very cost-effective opportunity for the clinical development of niacin for treating NAFLD and fatty liver disease.

Elevated high-density lipoprotein cholesterol and cardiovascular mortality in maintenance hemodialysis patients.

BACKGROUND: High-density lipoprotein (HDL) confers protection against atherosclerosis by several different mechanisms. Although in the general population, increasing levels of HDL are associated with reduced cardiovascular (CV) mortality, this association is not well known in patients with chronic disease states such as end-stage renal disease. We hypothesize that the association of serum HDL concentration and its ratio to total cholesterol with all-cause and CV mortality in hemodialysis patients is different from the general population. METHODS: A 3-year (July 2004 to June 2007) cohort of 33 109 chronic hemodialysis patients was studied in the USA in the dialysis clinics where lipid profile was measured in at least 50% of all outpatients of the clinic during a given calendar quarter. Cox proportional hazard models were adjusted for demographics and case-mix variables and cubic splines were plotted. RESULTS: Higher HDL concentrations up to 50 mg/dL were associated with better overall survival, while HDL at 60 mg/dL and above was associated with a rise in all-cause and CV mortality. All-cause and CV mortality hazard ratio was 1.28 (1.20-1.38) and 1.08 (1.01-1.16) for HDL <30 mg/dL and 1.05 (1.00-1.10) and 1.08 (1.00-1.16) for HDL ≥ 60 mg/dL, respectively (reference: HDL: 30-<60 mg/dL). CONCLUSIONS: In contrast to the general population, low total cholesterol to HDL ratio was associated with higher mortality in hemodialysis patients. A U-shaped association between HDL cholesterol level and all-cause and CV mortality exists in hemodialysis patients with HDL between 50 and <60 mg/dL exhibiting the best survival. The underlying mechanisms responsible for these seemingly paradoxical associations await further investigation.

Recent advances in niacin and lipid metabolism.

PURPOSE OF REVIEW: This review focuses on the current understanding of the physiological mechanisms of action of niacin on lipid metabolism and atherosclerosis. RECENT FINDINGS: Emerging findings indicate that niacin decreases hepatic triglyceride synthesis and subsequent VLDL/LDL secretion by directly and noncompetitively inhibiting hepatocyte diacylglycerol acyltransferase 2. Recent studies in mice lacking niacin receptor GPR109A and human clinical trials with GPR109A agonists disproved the long believed hypothesis of adipocyte triglyceride lipolysis as the mechanism for niacin's effect on serum lipids. Niacin, through inhibiting hepatocyte surface expression of ß-chain ATP synthase, inhibits the removal of HDL-apolipoprotein (apo) AI resulting in increased apoAI-containing HDL particles. Additional recent findings suggest that niacin by increasing hepatic ATP-binding cassette transporter A1-mediated apoAI lipidation increases HDL biogenesis, thus stabilizing circulation of newly secreted apoAI. New concepts have also emerged on lipid-independent actions of niacin on vascular endothelial oxidative and inflammatory events, myeloperoxidase release from neutrophils and its impact on HDL function, and GPR109A-mediated macrophage inflammatory events involved in atherosclerosis. SUMMARY: Recent advances have provided physiological mechanisms of action of niacin on lipid metabolism and atherosclerosis. Better understanding of niacin's actions on multiple tissues and targets may be helpful in designing combination therapy and new treatment strategies for atherosclerosis.

Mammalian colonocytes possess a carrier-mediated mechanism for uptake of vitamin B3 (niacin): studies utilizing human and mouse colonic preparations.

Niacin (vitamin B3; nicotinic acid) plays an important role in maintaining redox state of cells and is obtained from endogenous and exogenous sources. The latter source has generally been assumed to be the dietary niacin, but another exogenous source that has been ignored is the niacin that is produced by the normal microflora of the large intestine. For this source of niacin to be bioavailable, it needs to be absorbed, but little is known about the ability of the large intestine to absorb niacin and the mechanism involved. Here we addressed these issues using the nontransformed human colonic epithelial NCM460 cells, native human colonic apical membrane vesicles (AMV) isolated from organ donors, and mouse colonic loops in vivo as models. Uptake of ³H-nicotinic acid by NCM460 cells was: 1) acidic pH (but not Na⁺) dependent; 2) saturable (apparent Km = 2.5 ± 0.8 µM); 3) inhibited by unlabeled nicotinic acid, nicotinamide, and probenecid; 4) neither affected by other bacterially produced monocarboxylates, monocarboxylate transport inhibitor, or by substrates of the human organic anion transporter-10; 5) affected by modulators of the intracellular protein tyrosine kinase- and Ca²âº-calmodulin-regulatory pathways; and 6) adaptively regulated by extracellular nicotinate level. Uptake of nicotinic acid by human colonic AMV in vitro and by mouse colonic loops in vivo was also carrier mediated. These findings report, for the first time, that mammalian colonocytes possess a high-affinity carrier-mediated mechanism for nicotinate uptake and show that the process is affected by intracellular and extracellular factors.

Role of HDL dysfunction in end-stage renal disease: a double-edged sword.

End-stage renal disease (ESRD) is associated with a significant propensity for development of atherosclerosis and cardiovascular mortality. The atherogenic diathesis associated with ESRD is driven by inflammation, oxidative stress, and dyslipidemia. Reduced high-density lipoprotein cholesterol (HDL-C) level and high-density lipoprotein (HDL) dysfunction are the hallmarks of ESRD-related dyslipidemia. Clinical and laboratory studies have revealed that ESRD is associated with significantly reduced serum apolipoprotein A-I (ApoA-I) and HDL-C level as well as altered HDL composition. Furthermore, although ESRD is associated with impaired HDL antioxidant and anti-inflammatory properties in most patients, in a small subset, HDL may in fact have a pro-oxidant and proinflammatory effect. Therefore, it is no surprise that serum HDL-C level is not a dependable indicator of cardiovascular disease burden in ESRD, and markers such as HDL function are critical to accurately identifying patients at risk for cardiovascular disease and mortality in ESRD.

Niacin increases human aortic endothelial Sirt1 activity and nitric oxide: effect on endothelial function and vascular aging.

OBJECTIVES: Vascular endothelium, the innermost monolayer of endothelial cells lining the vessel wall, plays a vital physiologic role in the functional integrity of the aorta. Endothelial-derived nitric oxide (NO) is an important molecule regulating vascular endothelial function by its vasodilatory properties and inhibiting pathological inflammatory and oxidative consequences of vascular aging and cardiovascular disorders. Sirtuin 1 (Sirt1), has recently emerged as an important regulator of vascular endothelial NO production. The effect of niacin on Sirt1 in human arterial tissue has not been studied. METHODS: Using primary cultures of human aortic endothelial cells (HAEC), we examined the effect of niacin on endothelial Nicotinamide Adenine Dinucleotide+ (NAD+), Sirt1 and NO production. RESULTS: In HAEC, we show that pharmacologically relevant doses of niacin at 0.2-0.3 mM for 24 h significantly increased cellular NAD+ levels, Sirt1 activity, and NO production as compared to controls. Using silencing of Sirt1 by siRNA, we observed that Sirt1 mediates niacin-induced NO production. CONCLUSIONS: Translationally, these findings suggest that Sirt1 activation by niacin may be one of the mechanisms of action of niacin acting on NO to improve endothelial function and mitigate human vascular aging and its deleterious cardiovascular consequences.

Niacin increases HDL biogenesis by enhancing DR4-dependent transcription of ABCA1 and lipidation of apolipoprotein A-I in HepG2 cells.

The lipidation of apoA-I in liver greatly influences HDL biogenesis and plasma HDL levels by stabilizing the secreted apoA-I. Niacin is the most effective lipid-regulating agent clinically available to raise HDL. This study was undertaken to identify regulatory mechanisms of niacin action in hepatic lipidation of apoA-I, a critical event involved in HDL biogenesis. In cultured human hepatocytes (HepG2), niacin increased: association of apoA-I with phospholipids and cholesterol by 46% and 23% respectively, formation of lipid-poor single apoA-I molecule-containing particles up to ~2.4-fold, and pre ß 1 and α migrating HDL particles. Niacin dose-dependently stimulated the cell efflux of phospholipid and cholesterol and increased transcription of ABCA1 gene and ABCA1 protein. Mutated DR4, a binding site for nuclear factor liver X receptor alpha (LXR α ) in the ABCA1 promoter, abolished niacin stimulatory effect. Further, knocking down LXR α or ABCA1 by RNA interference eliminated niacin-stimulated apoA-I lipidation. Niacin treatment did not change apoA-I gene expression. The present data indicate that niacin increases apoA-I lipidation by enhancing lipid efflux through a DR4-dependent transcription of ABCA1 gene in HepG2 cells. A stimulatory role of niacin in early hepatic formation of HDL particles suggests a new mechanism that contributes to niacin action to increase the stability of newly synthesized circulating HDL.

Niacin regresses collagen content in human hepatic stellate cells from liver transplant donors with fibrotic non-alcoholic steatohepatitis (NASH).

In patients with non-alcoholic steatohepatitis (NASH), the onset of fibrosis is a major predictor of cirrhosis and its deadly complications. There is no approved effective pharmacologic therapy for liver fibrosis. Niacin (in pharmacologic concentrations or dose) reverses hepatic steatosis and steatohepatitis. Niacin's efficacy on human hepatic fibrosis is unknown. We investigated the effect of niacin on reversal of preexisting collagen content, in cultured primary human hepatic stellate cells (HSC) obtained from 7 donor livers (processed for transplantation) selected from 5 deceased patients having histologically diagnosed NASH with fibrosis (F1-F3) and 2 non-NASH-fibrosis subjects (Samsara Sciences, Inc., now LifeNet Health). Pharmacologically relevant concentrations of niacin produced a robust and significant dose and time-dependent regression of pre-existing fibrosis by an average of 47.6% and 60.1% (0.25 and 0.5 mM niacin at 48 h incubation) and 53.5% and 65.0% (0.25 and 0.5 mM niacin at 96 h incubation), respectively. In stellate cells from non-NASH-fibrosis subjects, niacin prevented, and regressed fibrosis induced by liver fibrosis stimulators, transforming growth factor-ß (TGF-ß) and hydrogen peroxide. Niacin significantly inhibited oxidative stress induced by stressors, palmitic acid, or hydrogen peroxide by 52% and 50%, respectively. Translationally, these human HSC data, coupled with emerging in vivo animal data and in vitro human hepatocyte data, suggest that niacin (used clinically for dyslipidemia) could be repurposed as an effective drug for the clinical treatment of patients with NASH-fibrosis or liver cirrhosis. This is in addition to its known efficacy for reversing steatohepatitis and steatosis which can also result in liver cirrhosis.

Pioglitazone increases apolipoprotein A-I production by directly enhancing PPRE-dependent transcription in HepG2 cells.

Pioglitazone, a hypoglycemic agent, has been shown to increase plasma HDL cholesterol, but the mechanism is incompletely understood. We further investigated effects of pioglitazone on transcriptional regulation of apolipoprotein (apo)A-I gene and functional properties of pioglitazone-induced apoA-I-containing particles. Pioglitazone dose-dependently stimulated apoA-I promoter activities in HepG2 cells. A peroxisome proliferator-activated receptor (PPAR)-response element located in site A (-214 to -192 bp, upstream of the transcription start site) of the promoter is required for pioglitazone-induced apoA-I gene transcription. Deletion of site A (-214 to -192 bp), B (-169 to -146 bp), or C (-134 to -119 bp), which clusters a number of cis-acting elements for binding of different transcription factors, reduced the basal apoA-I promoter activities, and no additional pioglitazone-sensitive elements were found within this region. Overexpression or knock-down of liver receptor homolog-1, a newly identified nuclear factor with strong stimulatory effect on apoA-I transcription, did not alter pioglitazone-induced apoA-I transcription. Pioglitazone-induced apoA-I transcription is mainly mediated through PPARalpha but not PPARgamma in hepatocytes. Pioglitazone induced production of HDL enriched in its subfraction containing apoA-I without apoA-II, which inhibited monocyte adhesion to endothelial cells in vitro. In conclusion, pioglitazone increases apoA-I production by directly enhancing PPAR-response element-dependent transcription, resulting in generation of apoA-I-containing HDL particles with increased anti-inflammatory property.

Niacin: an old drug rejuvenated.

Niacin has long been used in the treatment of dyslipidemia and cardiovascular disease. Recent research on niacin has been focused on understanding the mechanism of action of niacin and preparation of safer niacin formulations. New findings indicate that niacin does the following: 1) it inhibits hepatic diacylglycerol acyltransferase 2, resulting in inhibition of triglyceride synthesis and decreased apolipoprotein B-containing lipoproteins; 2) it decreases the surface expression of hepatic adenosine triphosphate synthase beta-chain, leading to decreased holoparticle high-density lipoprotein catabolism and increased high-density lipoprotein levels; and 3) it increases redox potential in arterial endothelial cells, resulting in inhibition of redox-sensitive genes. Flushing, an adverse effect of niacin, results from niacin receptor GPR109A-mediated production of prostaglandin D2 and E2 via DP1 and EP2/4 receptors. DP1 receptor antagonist (laropiprant) attenuates the niacin flush. A reformulated preparation of extended-release niacin (Niaspan; Abbott, Abbott Park, IL) lowers flushing compared with an older Niaspan formulation. These advancements in niacin research have rejuvenated its use for the treatment of dyslipidemia and cardiovascular disease.

Acetylsalicylic acid reduces niacin extended-release-induced flushing in patients with dyslipidemia.

BACKGROUND: Niacin extended-release (NER) is safe and effective for treatment of dyslipidemia. However, some patients discontinue NER treatment because of flushing, the most common adverse event associated with niacin therapy. OBJECTIVE: To evaluate the effect of daily oral acetylsalicylic acid (ASA) on NER-induced flushing in patients with dyslipidemia. METHODS: A randomized, double-blind, placebo-controlled, multicenter, 5-week study was conducted (ClinicalTrials.gov identifier: NCT00626392). Patients (n = 277) were randomly assigned to one of six treatment arms and received a 1-week run-in with ASA 325 mg or placebo followed by 4 weeks of ASA 325 mg or placebo 30 minutes before NER at a starting dose of 500 mg or 1000 mg; all patients were titrated to NER 2000 mg at week 3. The primary endpoint was the maximum severity of flushing events during week 1. RESULTS: In week 1, ASA run-in, ASA pretreatment, and a lower starting dosage of NER (500 mg/day) resulted in reductions in mean maximum severity of flushing; 48% fewer patients who received ASA experienced flushing episodes of moderate or greater intensity relative to placebo (absolute rates 15% vs 29%; p = 0.01). Over 4 weeks, ASA reduced the number of flushing episodes/patient/week by 42% relative to placebo. The discontinuation rate due to flushing was lower in the ASA group compared with placebo (1.8% vs 9.4%; p = 0.007). Overall safety was not different between groups. CONCLUSION: These data suggest that a clinically meaningful reduction in the severity and incidence of NER-induced flushing may be achieved with ASA use.

Niacin for treatment of nonalcoholic fatty liver disease (NAFLD): novel use for an old drug?

Niacin has been widely used clinically for over half a century for dyslipidemia. Recent new evidence indicates that niacin may be useful in the treatment of nonalcoholic fatty liver disease (NAFLD) and its sequential complications including nonalcoholic steatohepatitis and fibrosis. There is an urgent unmet need for a cost-effective solution for this public health problem affecting nearly one in three adults. Niacin inhibits and reverses hepatic steatosis and inflammation in animals and liver cell cultures. It prevents liver fibrosis in animals and decreases collagen in cultured human stellate cells. Its mechanism of action is by oxidative stress reduction and inhibition of diacylglycerol acyltransferase 2 and other possible targets. An uncontrolled clinical trial in 39 hypertriglyceridemic patients with steatosis showed reduction of liver fat by 47% and reductions in liver enzymes and C-reactive protein from the baseline when treated with niacin extended-release for 6 months These hypothesis-generating data indicate a novel repurposed use of niacin for NAFLD. Niacin beneficially affects NAFLD at 3 major stages directly and, by affecting steatosis, it indirectly decreases the cascade effect on inflammation and fibrosis. It offers the advantage potentially of combination with other drugs in development for evolving synergistically more intense and broader efficacy. In select patients, it may benefit frequently associated atherogenic dyslipidemia. A randomized placebo-controlled double-blind parallel trial (with niacin alone or in combination with another drug in development) to assess the safety and efficacy of niacin on steatosis, inflammation, and fibrosis in patients with nonalcoholic steatohepatitis/NAFLD is warranted.

Statin Therapy Before Transition to End-Stage Renal Disease With Posttransition Outcomes.

Background Although studies have shown that statin therapy in patients with non-dialysis-dependent chronic kidney disease was associated with a lower risk of death, this was not observed in dialysis patients newly initiated on statins. It is unclear if statin therapy benefits administered during the predialysis period persist after transitioning to end-stage renal disease. Methods and Results In 47 720 veterans who transitioned to end-stage renal disease during 2007 to 2014, we examined the association of statin therapy use 1 year before transition with posttransition all-cause and cardiovascular mortality and hospitalization incidence rates over the first 12 months of follow-up. Associations were examined using multivariable adjusted Cox proportional hazard models and negative binomial regressions. Sensitivity analyses included propensity score and subgroup analyses. The cohort's mean± SD age was 71±11 years, and the cohort included 4% women, 23% blacks, and 66% diabetics. Over 12 months of follow-up, there were 13 411 deaths, with an incidence rate of 35.3 (95% CI , 34.7-35.8) deaths per 100 person-years. In adjusted models, statin therapy compared with no statin therapy was associated with lower risks of 12-month all-cause (hazard ratio [95% CI], 0.79 [0.76-0.82]) and cardiovascular (hazard ratio [95% CI ], 0.83 [0.78-0.88]) mortality, as well as with a lower rate of hospitalizations (incidence rate ratio [95% CI ], 0.89 [0.87-0.92]) after initiating dialysis. These lower outcome risks persisted across strata of clinical characteristics, and in propensity score analyses. Conclusions Among veterans with non-dialysis-dependent chronic kidney disease, treatment with statin therapy within the 1 year before transitioning to end-stage renal disease is associated with favorable early end-stage renal disease outcomes.

Effects of Extended-Release Niacin on Quartile Lp-PLA2 Levels and Clinical Outcomes in Statin-treated Patients with Established Cardiovascular Disease and Low Baseline Levels of HDL-Cholesterol: Post Hoc Analysis of the AIM HIGH Trial.

BACKGROUND: Lipoprotein-associated phospholipase A2 (LpPLA2) is an inflammatory marker that has been associated with the presence of vulnerable plaque and increased risk of cardiovascular (CV) events. OBJECTIVE: To assess the effect of extended-release niacin (ERN) on Lp-PLA2 activity and clinical outcomes. METHODS: We performed a post hoc analysis in 3196 AIM-HIGH patients with established CV disease and low baseline levels of high-density lipoprotein cholesterol (HDL-C) who were randomized to ERN versus placebo on a background of simvastatin therapy (with or without ezetimibe) to assess the association between baseline Lp-PLA2 activity and the rate of the composite primary end point (CV death, myocardial infarction, stroke, hospitalization for unstable angina, and symptom-driven revascularization). RESULTS: Participants randomized to ERN, but not those randomized to placebo, experienced a significant 8.9% decrease in LpPLA2. In univariate analysis, the highest quartile of LpPLA2 activity (>208 nmol/min/mL, Q4) was associated with higher event rates compared to the lower quartiles in the placebo group (log rank P = .032), but not in the ERN treated participants (log rank P = .718). However, in multivariate analysis, adjusting for sex, diabetes, baseline LDL-C, HDL-C, and triglycerides, there was no significant difference in outcomes between the highest Lp-PLA2 activity quartile versus the lower quartiles in both the placebo and the ERN groups. CONCLUSION: Among participants with stable CV disease on optimal medical therapy, elevated Lp-PLA2 was associated with higher CV events; however, addition of ERN mitigates this effect. This association in the placebo group was attenuated after multivariable adjustment, which suggests that Lp-PLA2 does not improve risk assessment beyond traditional risk factors.

Serum Endocannabinoid Levels in Patients With End-Stage Renal Disease.

CONTEXT: Previous studies have shown that the endocannabinoid system plays a major role in energy metabolism through the actions of its main mediators, 2-arachidonoyl-sn-glycerol (2-AG) and anandamide (AEA). OBJECTIVE: We examined serum levels of major endocannabinoid mediators and their association with clinical parameters in patients with end-stage renal disease (ESRD). DESIGN AND SETTING: Serum concentrations of 2-AG and AEA were measured in patients on maintenance hemodialysis (MHD) and controls, and correlations with various clinical and laboratory indices were examined. 2-AG was also measured in age and sex-matched healthy subjects for comparison of levels in patients undergoing MHD. MAIN OUTCOME MEASURE: Serum 2-AG. RESULTS: Serum 2-AG levels were significantly elevated in patients with ESRD compared with healthy controls. Higher levels of 2-AG were found in patients on MHD compared to healthy subjects, and similar findings were seen in a second set of subjects in independent analyses. Among 96 patients on MHD, 2-AG levels correlated significantly and positively with serum triglycerides (ρ = 0.43; P < 0.0001), body mass index (ρ = 0.40; P < 0.0001), and body anthropometric measures and negatively with serum high-density lipoprotein cholesterol (ρ = -0.33; P = 0.001) following adjustment for demographic and clinical variables. CONCLUSIONS: In patients on MHD, levels of serum 2-AG, a major endocannabinoid mediator, were increased. In addition, increasing serum 2-AG levels correlated with increased serum triglycerides and markers of body mass. Future studies will need to evaluate the potential mechanisms responsible for these findings.

Association of Serum Paraoxonase/Arylesterase Activity With All-Cause Mortality in Maintenance Hemodialysis Patients.

CONTEXT: In end-stage renal disease (ESRD), serum high-density lipoprotein cholesterol (HDL-C) level is not an accurate predictor of mortality, partly because it does not necessarily correlate with indices of HDL function. Paraoxonase (PON) is a major enzyme constituent of HDL and a key component of HDL antioxidant activity. Apolipoprotein A-I (Apo A-1) is the core HDL structural protein that plays a major role in various aspects of HDL function. OBJECTIVE: We sought to examine PON activity and Apo A-I levels in patients with ESRD vs healthy controls. DESIGN AND SETTING: PON/arylesterase activity was measured in 499 patients with maintenance hemodialysis (MHD) and 24 healthy controls with similar distributions of age, sex, and race/ethnicity. Serum acrolein-modified Apo A-I was measured in 30 patients with MHD and 10 healthy controls. MAIN OUTCOME MEASURES: Multilevel Cox models were used to assess associations among PON activity, Apo A-I, and HDL-C levels with 12-month all-cause mortality. RESULTS: PON activity was significantly lower in patients with MHD vs controls. Furthermore, acrolein-modified Apo A-I levels were higher in patients with MHD vs controls. In fully adjusted models, high PON activity was associated with lower 12-month mortality, whereas no difference of mortality risk was observed across HDL-C levels. The combination of high PON and low Apo A-I compared with low PON and low Apo A-I was associated with lower mortality risk. CONCLUSIONS: In patients with MHD, PON activity had a stronger association with 12-month mortality than HDL-C. Future studies are needed to examine the role of these markers as potential diagnostic and therapeutic tools in ESRD.