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Potent peroxisome proliferator-activated receptor-α agonist treatment increases cholesterol efflux capacity in humans with the metabolic syndrome.
Khera, AV, Millar, JS, Ruotolo, G, Wang, MD, Rader, DJ
European heart journal. 2015;(43):3020-2
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AIMS: Fibrate medications weakly stimulate the nuclear receptor peroxisome proliferator-activated receptor-α (PPAR-α) and are currently employed clinically in patients with dyslipidaemia. The potent and selective agonist of PPAR-α LY518674 is known to substantially increase apolipoprotein A-I (apoA-I) turnover without major impact on steady-state levels of apoA-I or high-density lipoprotein-cholesterol (HDL-C). We sought to determine whether therapy with a PPAR-α agonist impacts cholesterol efflux capacity, a marker of HDL function. METHODS AND RESULTS Cholesterol efflux capacity was measured at baseline and after 8 weeks of therapy in a randomized, placebo-controlled trial involving participants with metabolic syndrome treated with either LY518674 100 μg daily (n = 13) or placebo (n = 15). Efflux capacity assessment was quantified using a previously validated ex vivo assay that measures the ability of apolipoprotein-B depleted plasma to mobilize cholesterol from macrophages. LY518674 led to a 15.7% increase from baseline (95% CI 3.3-28.1%; P = 0.02, P vs. placebo = 0.01) in efflux capacity. The change in apoA-I production rate in the active treatment arm was strongly linked to change in cholesterol efflux capacity (r = 0.67, P = 0.01). CONCLUSIONS Potent stimulation of PPAR-α leads to accelerated turnover of apoA-I and an increase in cholesterol efflux capacity in metabolic syndrome patients despite no change in HDL-C or apoA-I levels. This finding reinforces the notion that changes in HDL-C levels may poorly predict impact on functionality and thus has implications for ongoing pharmacologic efforts to enhance apoA-I metabolism.
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Elevated interleukin-10: a new cause of dyslipidemia leading to severe HDL deficiency.
Moraitis, AG, Freeman, LA, Shamburek, RD, Wesley, R, Wilson, W, Grant, CM, Price, S, Demosky, S, Thacker, SG, Zarzour, A, et al
Journal of clinical lipidology. 2015;(1):81-90
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BACKGROUND Low high-density lipoprotein cholesterol (HDL-C) is a risk factor for coronary artery disease. Investigating mechanisms underlying acquired severe HDL deficiency in noncritically ill patients ("disappearing HDL syndrome") could provide new insights into HDL metabolism. OBJECTIVE To determine the cause of low HDL-C in patients with severe acquired HDL deficiency. METHODS AND RESULTS Patients with intravascular large B-cell lymphoma (n = 2), diffuse large B-cell lymphoma (n = 1), and autoimmune lymphoproliferative syndrome (n = 1) presenting with markedly decreased HDL-C, low low-density lipoprotein cholesterol (LDL-C), and elevated triglycerides were identified. The abnormal lipoprotein profile returned to normal after therapy in all 4 patients. All patients were found to have markedly elevated serum interleukin-10 (IL-10) levels that also normalized after therapy. In a cohort of autoimmune lymphoproliferative syndrome patients (n = 93), IL-10 showed a strong inverse correlation with HDL-C (R(2) = 0.3720, P < .0001). A direct causal role for increased serum IL-10 in inducing the observed changes in lipoproteins was established in a randomized, placebo-controlled clinical trial of recombinant human IL-10 in psoriatic arthritis patients (n = 18). Within a week of initiating subcutaneous recombinant human IL-10 injections, HDL-C precipitously decreased to near-undetectable levels. LDL-C also decreased by more than 50% (P < .0001) and triglycerides increased by approximately 2-fold (P < .005). All values returned to baseline after discontinuing IL-10 therapy. CONCLUSION Increased IL-10 causes severe HDL-C deficiency, low LDL-C, and elevated triglycerides. IL-10 is thus a potent modulator of lipoprotein levels, a potential new biomarker for B-cell disorders, and a novel cause of disappearing HDL syndrome.
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Smoking associates with visceral fat accumulation especially in women.
Nakanishi, K, Nishida, M, Ohama, T, Moriyama, T, Yamauchi-Takihara, K
Circulation journal : official journal of the Japanese Circulation Society. 2014;(5):1259-63
Abstract
BACKGROUND Smoking and metabolic syndrome (MetS) are major public health problems in modern society and are important risk factors of cardiovascular disease (CVD). The association of smoking, MetS, and CVD is widely reported, but reports targeted to women are few. In the present study, we evaluated risk factors, including visceral fat area (VFA), for CVD and development of subclinical atherosclerosis in female smokers especially. METHODS AND RESULTS Subjects consisted of 162 apparent healthy female and male smokers, and 315 age-matched never-smokers who underwent a health examination in the Osaka University Health Care Center. For female smokers, lifestyle and carotid intima-media thickness (IMT) were evaluated. Triglycerides were significantly higher and high-density lipoprotein-cholesterol significantly lower in smokers than in never-smokers for both men and women. However, VFA was significantly high only in smoking women when compared with never-smokers. Multivariate analysis revealed that age, body mass index, and smoking were the independent predictors of high VFA in women. In addition, annual IMT increase was significantly higher in smokers than never-smokers in women. CONCLUSIONS VFA was notably high in female smokers, but the difference was not observed in men. Smoking habit is an important risk factor of visceral fat accumulation and progression of subclinical atherosclerosis in women.
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Resistant starch type 4-enriched diet lowered blood cholesterols and improved body composition in a double blind controlled cross-over intervention.
Nichenametla, SN, Weidauer, LA, Wey, HE, Beare, TM, Specker, BL, Dey, M
Molecular nutrition & food research. 2014;(6):1365-9
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A metabolic health crisis is evident as cardiovascular diseases (CVD) remain the leading cause of mortality in the United States. Effects of resistant starch type 4 (RS4), a prebiotic fiber, in comprehensive management of metabolic syndrome (MetS) remain unknown. This study examined the effects of a blinded exchange of RS4-enriched flour (30% v/v) with regular/control flour (CF) diet on multiple MetS comorbidities. In a double blind (participants-investigators), placebo-controlled, cluster cross-over intervention (n = 86, age≥18, 2-12 week interventions, 2-week washout) in the United States, individuals were classified as having MetS (With-MetS) or not (No-MetS) following International Diabetes Federation (IDF)-criteria. RS4 consumption compared with CF resulted in 7.2% (p = 0.002) lower mean total cholesterol, 5.5% (p = 0.04) lower non-HDL, and a 12.8% (p < 0.001) lower HDL cholesterol in the With-MetS group. No-MetS individuals had a 2.6% (p = 0.02) smaller waist circumference and 1.5% (p = 0.03) lower percent body fat following RS4 intervention compared to CF. A small but significant 1% increase in fat-free mass was observed in all participants combined (p = 0.02). No significant effect of RS4 was observed for glycemic variables and blood pressures. RS4 consumption improved dyslipidemia and body composition. Incorporation of RS4 in routine diets could offer an effective strategy for public cardio-metabolic health promotion.
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Relationship of lipoproteins to cardiovascular events: the AIM-HIGH Trial (Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides and Impact on Global Health Outcomes).
Guyton, JR, Slee, AE, Anderson, T, Fleg, JL, Goldberg, RB, Kashyap, ML, Marcovina, SM, Nash, SD, O'Brien, KD, Weintraub, WS, et al
Journal of the American College of Cardiology. 2013;(17):1580-4
Abstract
OBJECTIVES This study sought to examine the relationship between niacin treatment, lipoproteins, and cardiovascular (CV) outcomes in this secondary analysis of the AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides and Impact on Global Health Outcomes) trial. BACKGROUND During a 3-year follow-up in 3,414 patients with established CV disease and low high-density lipoprotein cholesterol (HDL-C) levels, combined niacin + low-density lipoprotein cholesterol (LDL-C)-lowering therapy did not reduce CV events compared with LDL-C-lowering therapy alone. METHODS Subjects taking simvastatin and/or ezetimibe were randomized to receive extended-release (ER) niacin 1,500 to 2,000 mg or minimal immediate-release niacin (≤ 150 mg) as placebo at bedtime. LDL-C levels in both groups were maintained from 40 to 80 mg/dl. Hazard ratios were estimated by using Cox proportional hazards models for relationships between lipoproteins and the composite endpoint of CV death, myocardial infarction, acute coronary syndrome, ischemic stroke, or symptom-driven revascularization. RESULTS CV outcomes were not associated with ER niacin in any baseline lipoprotein tertile. In a subset of patients in both the highest triglyceride (≥ 198 mg/dl) and lowest HDL-C (<33 mg/dl) tertiles, ER niacin showed a trend toward benefit (hazard ratio: 0.74, p = 0.073). In-trial LDL-C levels, non-HDL-C levels, and the total cholesterol/HDL-C ratio were positively associated with CV events in the control group, but these relationships were absent in the ER niacin group. CONCLUSIONS Baseline lipoprotein tertiles did not predict differential benefit or harm with ER niacin added to LDL-C-lowering therapy, but a small dyslipidemic subgroup may benefit. ER niacin attenuated expected relationships of lipoprotein risk factors with CV events, raising the possibility that nonlipoprotein actions of niacin could affect risk. (Niacin Plus Statin to Prevent Vascular Events [AIM-HIGH]; NCT00120289).
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Altered relationship of plasma triglycerides to HDL cholesterol in patients with HIV/HAART-associated dyslipidemia: further evidence for a unique form of metabolic syndrome in HIV patients.
Vu, CN, Ruiz-Esponda, R, Yang, E, Chang, E, Gillard, B, Pownall, HJ, Hoogeveen, RC, Coraza, I, Balasubramanyam, A
Metabolism: clinical and experimental. 2013;(7):1014-20
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INTRODUCTION Plasma triglycerides (TG) and HDL-C are inversely related in Metabolic Syndrome (MetS), due to exchange of VLDL-TG for HDL-cholesteryl esters catalyzed by cholesteryl ester transfer protein (CETP). We investigated the relationship of TG to HDL-C in highly-active antiretroviral drug (HAART)-treated HIV patients. METHODS Fasting plasma TG and HDL-C levels were compared in 179 hypertriglyceridemic HIV/HAART patients and 71 HIV-negative persons (31 normotriglyceridemic (NL) and 40 hypertriglyceridemic due to type IV hyperlipidemia (HTG)). CETP mass and activity were compared in 19 NL and 87 HIV/HAART subjects. RESULTS Among the three groups, a plot of HDL-C vs. TG gave similar slopes but significantly different y-intercepts (9.24±0.45, 8.16±0.54, 6.70±0.65, sqrt(HDL-C) for NL, HIV and HTG respectively; P<0.001); this difference persisted after adjusting HDL-C for TG, age, BMI, gender, glucose, CD4 count, viral load and HAART strata (7.18±0.20, 6.20±0.05 and 4.55±0.15 sqrt(HDL-C) for NL, HIV and HTG, respectively, P<0.001). CETP activity was not different between NL and HIV, but CETP mass was significantly higher in HIV (1.47±0.53 compared to 0.93±0.27μg/mL, P<0.0001), hence CETP specific activity was lower in HIV (22.67±13.46 compared to 28.46±8.24nmol/μg/h, P=0.001). CONCLUSIONS Dyslipidemic HIV/HAART patients have a distinctive HDL-C plasma concentration adjusted for TG. The weak inverse relationship between HDL-C and TG is not explained by altered total CETP activity; it could result from a non-CETP-dependent mechanism or a decrease in CETP function due to inhibitors of CETP activity in HIV patients' plasma.
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Relationship of apolipoproteins A-1 and B, and lipoprotein(a) to cardiovascular outcomes: the AIM-HIGH trial (Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglyceride and Impact on Global Health Outcomes).
Albers, JJ, Slee, A, O'Brien, KD, Robinson, JG, Kashyap, ML, Kwiterovich, PO, Xu, P, Marcovina, SM
Journal of the American College of Cardiology. 2013;(17):1575-9
Abstract
OBJECTIVES This study sought to examine the relationship between baseline and on-study apolipoproteins (apo) A-1 and B and lipoprotein(a) [Lp(a)] levels and the development of subsequent cardiovascular (CV) events in the AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglyceride and Impact on Global Health Outcomes) trial. BACKGROUND Niacin has been reported to lower apoB and Lp(a) and to raise apoA-1. METHODS Individuals with CV disease and low baseline levels of high-density lipoprotein cholesterol were randomized to simvastatin plus placebo or simvastatin, plus extended-release niacin ([ERN], 1,500 to 2,000 mg/day), with ezetimibe added as needed, in both groups, to maintain an on-treatment low-density lipoprotein cholesterol in the range of 40 to 80 mg/dl. Hazard ratios (HRs) were used to evaluate the relationship between levels of apoA-1, apoB, and Lp(a), and CV events in each treatment group. RESULTS Baseline apoB and the apoB/apoA-I ratio were significantly predictive of CV events only for the placebo group (HR: 1.17 [p = 0.018] and HR: 1.19 [p = 0.016]). Baseline and on-study Lp(a) were predictive of CV events in both simvastatin plus placebo (baseline HR: 1.24 [p = 0.002] and on-study HR: 1.21 [p = 0.017]) and the simvastatin plus ERN group (baseline HR: 1.25 [p = 0.001] and on-study HR: 1.18 [p = 0.028]). The ERN modestly increased 1-year apoA-1 (7%), decreased apoB (13%), decreased the ApoB/ApoA-1 ratio (19%), and decreased Lp(a) 21%, but did not reduce CV events. CONCLUSIONS Lp(a) was associated with increased CV risk in both treatment groups indicating that it contributes to residual CV risk. However, there was no evidence that ERN reduced CV risk, despite favorable lipoprotein changes.
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The role of niacin in raising high-density lipoprotein cholesterol to reduce cardiovascular events in patients with atherosclerotic cardiovascular disease and optimally treated low-density lipoprotein cholesterol Rationale and study design. The Atherothrombosis Intervention in Metabolic syndrome with low HDL/high triglycerides: Impact on Global Health outcomes (AIM-HIGH).
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American heart journal. 2011;(3):471-477.e2
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BACKGROUND The aim of this study was to test the hypothesis that patients with atherosclerotic cardiovascular (CV) disease optimally treated on a statin but with residual atherogenic dyslipidemia (low high-density lipoprotein cholesterol [HDL-C] and high triglycerides) will benefit from addition of niacin with fewer CV events compared with placebo. Statin monotherapy trials have found 25%-35% CV risk reduction relative to placebo, leaving significant residual risk. Patients with atherogenic dyslipidemia have substantially increased CV risk. METHODS Participants were men and women with established CV disease and atherogenic dyslipidemia. Lipid entry criteria varied by gender and statin dose at screening. All participants received simvastatin (or simvastatin plus ezetimibe) at a dose sufficient to maintain low-density lipoprotein cholesterol (LDL-C) 40-80 mg/dL (1.03-2.07 mmol/L). Participants were randomized to extended-release niacin or matching placebo. The primary end point was time to occurrence of the first of the following: coronary heart disease death, nonfatal myocardial infarction, ischemic stroke, hospitalization for acute coronary syndrome, or symptom-driven coronary or cerebral revascularization. This event-driven trial will have 85% power to show a 25% reduction in primary event frequency after 850 patients have experienced a primary outcome event. RESULTS AIM-HIGH completed enrollment in April 2010. Follow-up is expected to continue through 2012. SUMMARY AIM-HIGH was designed to determine whether treating residual dyslipidemia with niacin further reduces cardiovascular events in patients with CV disease on a statin at target levels of low-density lipoprotein cholesterol.
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Dietary cholesterol from eggs increases plasma HDL cholesterol in overweight men consuming a carbohydrate-restricted diet.
Mutungi, G, Ratliff, J, Puglisi, M, Torres-Gonzalez, M, Vaishnav, U, Leite, JO, Quann, E, Volek, JS, Fernandez, ML
The Journal of nutrition. 2008;(2):272-6
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Carbohydrate-restricted diets (CRD) significantly decrease body weight and independently improve plasma triglycerides (TG) and HDL cholesterol (HDL-C). Increasing intake of dietary cholesterol from eggs in the context of a low-fat diet maintains the LDL cholesterol (LDL-C)/HDL-C for both hyper- and hypo-responders to dietary cholesterol. In this study, 28 overweight/obese male subjects (BMI = 25-37 kg/m2) aged 40-70 y were recruited to evaluate the contribution of dietary cholesterol from eggs in a CRD. Subjects were counseled to consume a CRD (10-15% energy from carbohydrate) and they were randomly allocated to the EGG group [intake of 3 eggs per day (640 mg/d additional dietary cholesterol)] or SUB group [equivalent amount of egg substitute (0 dietary cholesterol) per day]. Energy intake decreased in both groups from 10,243 +/- 4040 to 7968 +/- 2401 kJ (P < 0.05) compared with baseline. All subjects irrespective of their assigned group had reduced body weight and waist circumference (P < 0.0001). Similarly, the plasma TG concentration was reduced from 1.34 +/- 0.66 to 0.83 +/- 0.30 mmol/L after 12 wk (P < 0.001) in all subjects. The plasma LDL-C concentration, as well as the LDL-C:HDL-C ratio, did not change during the intervention. In contrast, plasma HDL-C concentration increased in the EGG group from 1.23 +/- 0.39 to 1.47 +/- 0.38 mmol/L (P < 0.01), whereas HDL-C did not change in the SUB group. Plasma glucose concentrations in fasting subjects did not change. Eighteen subjects were classified as having the metabolic syndrome (MetS) at the beginning of the study, whereas 3 subjects had that classification at the end. These results suggest that including eggs in a CRD results in increased HDL-C while decreasing the risk factors associated with MetS.