Control High-density Lipoprotein Research Articles

Anti-Inflammatory Effect of High-Density Lipoprotein Blunted by Delivery of Altered MicroRNA Cargo in Patients With Rheumatoid Arthritis.

High-density lipoprotein (HDL) has well-characterized anti-atherogenic cholesterol efflux and antioxidant functions. Another function of HDL uncharacterized in rheumatoid arthritis (RA) is its ability to transport microRNAs (miRNAs) between cells and thus alter cellular function. The study's purpose was to determine if HDL-miRNA cargo is altered and affects inflammation in RA. HDL-microRNAs were characterized in 30 RA and 30 control participants by next generation sequencing and quantitative polymerase chain reaction. The most abundant differentially expressed miRNA was evaluated further. The function of miR-1246 was assessed by miRNA mimics, antagomiRs, small interfering RNA knockdown, and luciferase assays. Monocyte-derived macrophages were treated with miR-1246-loaded HDL and unmodified HDL from RA and control participants to measure delivery of miR-1246 and its effect on interleukin-6 (IL-6). The most abundant miRNA on HDL was miR-1246; it was significantly enriched two-fold on HDL from RA versus control participants. HDL-mediated miR-1246 delivery to macrophages significantly increased IL6 expression 43-fold. miR-1246 delivery significantly decreased DUSP3 1.5-fold and DUSP3 small interfering RNA knockdown increased macrophage IL6 expression. Luciferase assay indicated DUSP3 is a direct target of miR-1246. Unmodified HDL from RA delivered 1.6-fold more miR-1246 versus control participant HDL. Unmodified HDL from both RA and control participants attenuated activated macrophage IL6 expression, but this effect was significantly blunted in RA so that IL6 expression was 3.4-fold higher after RA versus control HDL treatment. HDL-miR-1246 was increased in RA versus control participants and delivery of miR-1246 to macrophages increased IL-6 expression by targeting DUSP3. The altered HDL-miRNA cargo in RA blunted HDL's anti-inflammatory effect.

Cookies enriched with anethole and secoisolariciresinol diglucoside from flaxseed and fennel seeds improve hypercholesterolemia, lipid profile, and liver functions: A pilot study.

Over millennia, flaxseeds and fennel seeds have captured greater attention owing to the broad spectrum of bioactive compounds and their respective therapeutic potential. They are well-known therapeutic plants, frequently used in home treatments for a variety of medical conditions. The novelty of this pilot study is to assess the beneficial health effects of secoisolariciresinol diglucoside (SDG) and anethole-based enriched cookies among hyperlipidemic patients. The result of sensory evaluation revealed that cookies with anethole and SDG (500 + 500 mg/day) were significantly acceptable in terms of color, texture, taste, and overall acceptability same as that of control. This study was performed among 34 patients with hyperlipidemia in a university-affiliated hospital, Lahore, Pakistan. In this study, patients received dietary supplementation with anethole and SDG (500 + 500 mg/day) administered in cookies for 8 weeks. Patients were assigned into two groups, intervention (receiving anethole + SDG-enriched cookies; n = 16) and placebo (n = 18), for 8 weeks. Both groups maintained the same diet and lifestyle. Pre- and postintervention weight, lipid profile, and liver enzyme levels were measured. Analysis of covariance and paired sample t-test were used for comparing the two groups. After 8 weeks, a significant mean weight loss was observed in the intervention group (4.26%) as compared to the placebo group (0.3%). A significant reduction of TC (177.02 ± 5.14 mg/dL; p = .024), TG (150.19 ± 7.94 mg/dL; p = .032), and LDL (87.38 ± 3.58 mg/dL; p = .001) were compared to the control group and HDL level (57.09 ± 3.90 mg/dL; p = .035) were increased in the intervention group as compared to the placebo. Meanwhile, it had a minor improvement in AST (30.97 ± 2.95 U/L; p = .01), ALT (33.05 ± 1.52 U/L; p = .025), and ALP (112.15 ± 4.03 U/L; p = .03) among the intervention group. Thus, based on the results from the study, it can be said that anethole + SDG-enriched bakery products could be developed as a functional dietary option for hyperlipidemia in developing countries like Pakistan.

Dalcetrapib and anacetrapib increase apolipoprotein E-containing HDL in rabbits and humans

The large HDL particles generated by administration of cholesteryl ester transfer protein inhibitors (CETPi) remain poorly characterized, despite their potential importance in the routing of cholesterol to the liver for excretion, which is the last step of the reverse cholesterol transport. Thus, the effects of the CETPi dalcetrapib and anacetrapib on HDL particle composition were studied in rabbits and humans. The association of rabbit HDL to the LDL receptor (LDLr) in vitro was also evaluated. New Zealand White rabbits receiving atorvastatin were treated with dalcetrapib or anacetrapib. A subset of patients from the dal-PLAQUE-2 study treated with dalcetrapib or placebo were also studied. In rabbits, dalcetrapib and anacetrapib increased HDL-C by more than 58% (P < 0.01) and in turn raised large apo E-containing HDL by 66% (P < 0.001) and 59% (P < 0.01), respectively. Additionally, HDL from CETPi-treated rabbits competed with human LDL for binding to the LDLr on HepG2 cells more than control HDL (P < 0.01). In humans, dalcetrapib increased concentrations of large HDL particles (+69%, P < 0.001) and apo B-depleted plasma apo E (+24%, P < 0.001), leading to the formation of apo E-containing HDL (+47%, P < 0.001) devoid of apo A-I. Overall, in rabbits and humans, CETPi increased large apo E-containing HDL particle concentration, which can interact with hepatic LDLr. The catabolism of these particles may depend on an adequate level of LDLr to contribute to reverse cholesterol transport.

Early time-restricted feeding improves high-density lipoprotein amount and function in nonhuman primates, without effects on body composition.

Time-restricted feeding (TRF), whereby caloric intake is limited to a <12-hour window, is a potential regimen to ameliorate metabolic syndrome and cardiovascular disease (CVD) risk co-occurring with aging and with obesity. Early TRF (eTRF; early morning feeding followed by overnight fasting) times calorie consumption with hepatic circadian gene expression rhythms. Brief TRF trials demonstrate that high-density lipoprotein (HDL) cholesterol increases similar to diet/exercise interventions, which may impart beneficial CVD effects. Using a nonhuman primate (NHP) model, the efficacy of eTRF to raise HDL and increase plasma cholesterol efflux capacity (CEC) (primarily mediated by cholesterol efflux to HDL particles, a process that is inversely associated with CVD risk) was examined. Adult (8-16 years old, n=25) and geriatric (≥17 years old) NHPs were randomized to ad libitum feeding or eTRF for 12 months, and relevant body composition, glycemic control, and plasma HDL cholesterol levels and CEC were measured. Impaired CEC was found in geriatric NHPs. eTRF induced larger-sized HDL particles, increased HDL apolipoprotein A-1 content, lowered triglyceride concentrations, and increased plasma CEC (primarily to HDL particles) in both adult and geriatric NHPs without changes in glycemic control or body composition. A beneficial effect of eTRF on increasing HDL CEC in NHPs was demonstrated.

Effect of eight weeks of regular aerobic exercise on apolipoprotein AI gene expression and lipid profile indices in obese women

Background: Heart disease is a multifactorial disease with genetic background and environmental factors involved. And new studies believe that markers such as apolipoprotein AI are a better criterion for diagnosis. Therefore, the purpose of this study was to investigate the effect of eight weeks of regular aerobic exercise on apolipoprotein AI gene expression and lipid profile indices in obese women. Methods: In this experimental study, 30 healthy obese women aged 35-30 years were randomly selected and divided into control (n =15) and experimental (n =15) groups. The experimental group underwent 8 weeks of regular aerobic exercise at 60-75% of the heart rate reserve three sessions per week for 60 minutes each session. Apolipoprotein AI mRNA expression was measured by Semi-quantitative-RT-PCR method and lipid profiles were measured in both pre-test and post-test. Results: The apolipoprotein AI gene expression was significantly increased in the experimental group compared to the control group (P&lt;0.05). Also, TG (P = 0.003), TG LDL in the experimental group showed a significant decrease compared to the control group and HDL level in the experimental group was significantly higher than the control group (P = 0.001) Conclusion: The regular aerobic exercise has an important role in reducing cardiovascular diseases through increasing apolipoprotein AI gene expression and improving lipid

Serum levels of total sialic acid and lipid profile with the severity of the vessel in patients with non-smoker and diabetic coronary artery disease

Background: Coronary Artery Disease (CAD) is a major cause of mortality in most countries. Many risk factors such as high blood pressure, hyperlipidemia, diabetes, age, sex, obesity, smoking, and family history play a role in CAD. The aim of this study was to evaluate the concentration of Total Sialic Acid (TSA) and Lipid Profiles (LP) with the Severity of the Vessel in patients with non-smoker and diabetic CAD, so that by measuring these parameters, effective help for diagnosis and prevention for healthy people Prone to CAD, and also control the treatment of patients. Methods: In this study, 200 individual including 160 patient and 40 control group were considered. All patient groups were non-smokers and diabetic. Patients were divided into 4 groups according to the results of angiography: Patients with Normal angiography (n = 40) with one eclipse (n = 40), patients with double stenosis (n = 40) and patients with eclipse Three vessels (n = 40). The control group was chosen from people who had no history of CAD and other diseases. The lipid profile was measured by standard methods and serum total sialic acid was measured by ELISA method. Results: There was no significant difference between the two groups in age and sex, but there was a significant difference in family history (p&lt;0.05). There was a significant difference in serum glucose level between the patient and the control group (p&lt;0.05), Also hs-CRP serum levels were normal in two patient and control groups. Serum levels of cholesterol, triglyceride and LDL in patient group were significantly higher than that of the control group but HDL serum level was adverse (p &lt;0.05), Also TSA serum level in the patient group was significantly higher than the control group (p&lt;0.05). Conclusion: Serum Total Sialic Acid level in non-smoker and diabetic CAD patients has a significant increase compared to the control group. It seems that the above biochemical parameters contribute significantly to the development and progression of atherosclerosis and CAD, by which timely measurements of these parameters in healthy individual probably can be helpful in preventing and improving CAD and controlling the treatment of patients.

An Increased Plasma Level of ApoCIII-Rich Electronegative High-Density Lipoprotein May Contribute to Cognitive Impairment in Alzheimer's Disease.

High-density lipoprotein (HDL) plays a vital role in lipid metabolism and anti-inflammatory activities; a dysfunctional HDL impairs cholesterol efflux pathways. To understand HDL’s role in patients with Alzheimer’s disease (AD), we analyzed the chemical properties and function. HDL from AD patients (AD-HDL) was separated into five subfractions, H1–H5, using fast-protein liquid chromatography equipped with an anion-exchange column. Subfraction H5, defined as the most electronegative HDL, was increased 5.5-fold in AD-HDL (23.48 ± 17.83%) in comparison with the control HDL (4.24 ± 3.22%). By liquid chromatography mass spectrometry (LC/MSE), AD-HDL showed that the level of apolipoprotein (apo)CIII was elevated but sphingosine-1-phosphate (S1P)-associated apoM and anti-oxidative paraoxonase 1 (PON1) were reduced. AD-HDL showed a lower cholesterol efflux capacity that was associated with the post-translational oxidation of apoAI. Exposure of murine macrophage cell line, RAW 264.7, to AD-HDL induced a vibrant expression of ganglioside GM1 in colocalization with apoCIII on lipid rafts alongside a concomitant increase of tumor necrosis factor-α (TNF-α) detectable in the cultured medium. In conclusion, AD-HDL had a higher proportion of H5, an apoCIII-rich electronegative HDL subfraction. The associated increase in pro-inflammatory (apoCIII, TNF-α) components might favor Amyloid β assembly and neural inflammation. A compromised cholesterol efflux capacity of AD-HDL may also contribute to cognitive impairment.

Abstract 14088: Pro-neurotensin/neuromedin N is Associated With Incident Metabolic Syndrome

Introduction: The tridecapeptide neurotensin increases dietary fatty acid uptake and is implicated in insulin resistance in animal models and—through plasma levels of its stable precursor pro-neurotensin/neuromedin N (pro-NT/NMN)—with human diabetes mellitus, obesity, and cardiovascular disease. We evaluated the association of pro-NT/NMN with incident metabolic syndrome (MetS). Methods: This analysis included a subcohort of 2,770 Black and White participants without prevalent MetS at baseline (2003-2007) from the REasons for Geographic And Racial Differences in Stroke study who had fasting plasma pro-NT/NMN measured by immunoassay and completed a second assessment from 2013-2016. Incident MetS was defined as ≥3 harmonized criteria at follow-up: impaired glycemic control, high systolic blood pressure, high triglycerides, low high-density lipoprotein (HDL), and increased waist circumference. Four sequential weighted logistic regression models were fitted to incident MetS overall and for each criterion separately, incorporating demographic factors, metabolic risk factors, HOMA-IR, and diet scores. Results: Over mean 9.4 (standard deviation [SD] 1.0) years follow up, 564 participants developed MetS. Median [IQR] plasma pro-NT/NMN was 160 [118-218] pmol/L. In the overall group, higher log pro-NT/NMN was associated with incidence of lower HDL (odds ratio [OR] per SD pro-NT/NMN 1.16, 95% confidence interval [CI] 1.00-1.35) and impaired glycemic control (1.25, 95% CI 1.11-1.40), but not other MetS components. Each SD higher log pro-NT/NMN was associated with a 22% increased odds of incident MetS, adjusted for demographics (Table); this was not significant when controlling for HOMA-IR in all but the White subgroup (race p -interaction 0.05). No differences by sex were observed. Conclusions: Higher neurotensin likely augments insulin resistance to increase odds of incident metabolic syndrome through impaired glycemic control and lower HDL.

Serum levels of Total Sialic Acid and Lipid Profile with the Severity of the Vessel in patients with non-smoker and diabetic Coronary Artery Disease

Background: Coronary Artery Disease (CAD) is a major cause of mortality in most countries. Many risk factors such as high blood pressure, hyperlipidemia, diabetes, age, sex, obesity, smoking, and family history play a role in CAD. The aim of this study was to evaluate the concentration of Total Sialic Acid (TSA) and Lipid Profiles (LP) with the Severity of the Vessel in patients with non-smoker and diabetic CAD, so that by measuring these parameters, effective help for diagnosis and prevention for healthy people Prone to CAD, and also control the treatment of patients. Methods: In this study, 200 individual including 160 patient and 40 control group were considered. All patient groups were non-smokers and diabetic. Patients were divided into 4 groups according to the results of angiography: Patients with Normal angiography (n = 40) with one eclipse (n = 40), patients with double stenosis (n = 40) and patients with eclipse Three vessels (n = 40). The control group was chosen from people who had no history of CAD and other diseases. The lipid profile was measured by standard methods and serum total sialic acid was measured by ELISA method. Results: There was no significant difference between the two groups in age and sex, but there was a significant difference in family history (p<0.05). There was a significant difference in serum glucose level between the patient and the control group (p<0.05), Also hs-CRP serum levels were normal in two patient and control groups. Serum levels of cholesterol, triglyceride and LDL in patient group were significantly higher than that of the control group but HDL serum level was adverse (p <0.05), Also TSA serum level in the patient group was significantly higher than the control group (p<0.05). Conclusion: Serum Total Sialic Acid level in non-smoker and diabetic CAD patients has a significant increase compared to the control group. It seems that the above biochemical parameters contribute significantly to the development and progression of atherosclerosis and CAD, by which timely measurements of these parameters in healthy individual probably can be helpful in preventing and improving CAD and controlling the treatment of patients.

Endothelial lipase increases eNOS activating capacity of high-density lipoprotein

Endothelial lipase (EL) changes structural and functional properties of high-density lipoprotein (HDL). HDL is a relevant modulator of endothelial nitric oxide synthase (eNOS) activity, but the effect of EL on HDL induced eNOS-activation has not yet been investigated. Here, we examined the impact of EL-modified HDL (EL-HDL) on eNOS activity, subcellular trafficking, and eNOS- dependent vasorelaxation. EL-HDL and empty virus (EV)-HDL as control were isolated from human serum incubated with EL-overexpressing or EV infected HepG2 cells. EL-HDL exhibited higher capacity to induce eNOS phosphorylation at Ser1177 and eNOS activity in EA.hy 926 cells, as well as eNOS-dependent vasorelaxation of mouse aortic rings compared to control HDL. As revealed by confocal and structured illumination-microscopy EL-HDL-driven induction of eNOS was accompanied by an increased eNOS-GFP targeting to the plasma membrane and a lower eNOS-GFP colocalization with Golgi and mitochondria. Widefield microscopy of filipin stained cells revealed that EL-HDL lowered cellular free cholesterol (FC) and as found by thin-layer chromatography increased cellular cholesterol ester (CE) content. Additionally, cholesterol efflux capacity, acyl-coenzyme A: cholesterol acyltransferase activity, and HDL particle uptake were comparable between EL-HDL and control HDL. In conclusion, EL increases eNOS activating capacity of HDL, a phenomenon accompanied by an enrichment of the plasma membrane eNOS pool, a decreased cell membrane FC and increased cellular CE content.

Could phthalates exposure contribute to the development of metabolic syndrome and liver disease in humans?

In the study, 305 patients of both genders were enrolled and divided into three groups: obese (BMI > 30 kg/m2), patients who were diagnosed type 2 diabetes mellitus (T2DM), and control, normal weight healthy volunteers. At least one of ten different phthalate metabolites was determined in the urine samples of 49.84% all enrolled participants. In the obese subgroup, the sum of all urinary phthalate metabolites was positively associated with TG levels (p = 0.031) together with derived TC/HDL and TG/HDL ratios (p = 0.023 and 0.015), respectively. Urinary MEP concentration was positively correlated with the HOMA-IR in T2DM subgroup (p = 0.016) while in the control subgroup, log10MEP levels were negatively correlated with total cholesterol (p = 0.0051), and LDL serum levels (p = 0.0015), respectively. Also, in the control subgroup, positive linear correlations between urinary log10MEP levels and TyG and TYG-BMI values (p = 0.028 and p = 0.027), respectively, were determined. Urinary MEHP levels were associated with glucose serum levels (p = 0.02) in T2DM subgroup, while in the control HDL values were negatively associated with log10MEHP (p = 0.0035). Healthy volunteers exposed to phthalates had elevated AST levels in comparison to non-exposed ones (p = 0.023). In control subgroup, ALT and AST values were increased (p = 0.02 and p = 0.01, respectively) in MEP exposed while GGT levels were enhanced (p = 0.017) in MEHP exposed in comparison with non-exposed. Combined phthalates influence on glucose and lipid metabolism may increase the possibility for NAFLD and insulin resistance development among exposed individuals.

PON-1 carbamylation is enhanced in HDL of uremia patients

High-density lipoprotein (HDL) carbamylation has been known in uremia patients. Paraoxonase-1 (PON-1) is an important HDL protein responsible for HDL anti-oxidant, arylesterase and lactonase activities. PON-1 carbamylation in uremic HDL has never been explored. We isolated HDL from uremia patients and control healthy subjects for study. Sandwich ELISA was used to estimate carbamylated PON-1 protein expression in HDL, and nanoflow liquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) was applied to identify the amino acid in PON-1 carbamylated. PON-1 enzyme activities were estimated by substrates conversion method. HDL anti-oxidant activity was gauged by fluorescence changes of indicator dye in the presence of H2O2. Our study results proved that the degree of PON-1 carbamylation was higher in uremic HDL than in control HDL. Sandwich ELISA study showed that carbamylated PON-1 concentration in uremic HDL was 1.49 ± 0.08 fold higher than that in HDL from controls (p < 0.05). The nanoLC-MS/MS showed that the carbamylation of lysine 290 (K290) of PON-1, a residue adjacent to PON-1 activity determining site, was detected in uremic HDL but not detected in control HDL. K290 carbamylation leads to local conformation changes that reduce accessible solvent accessibility. The HDL paraoxonase, arylesterase, and lactonase activities were all significantly lower in uremia patients than in control subjects. Additionally, HDL anti-antioxidant ability was also lower in uremia patients. Carbamylation of PON-1 in uremia patients could be one of the factors in impairing PON-1 enzyme activities and HDL anti-oxidation function.

Increased electronegativity of high-density lipoprotein in uremia patients impairs its functional properties and is associated with the risk of coronary artery disease

Background and aimsUremia patients have impaired high-density lipoprotein (HDL) function and a high risk of coronary artery disease (CAD). Increased lipoprotein electronegativity can compromise lipoprotein function, but the effect of increased HDL electronegativity on HDL function and its association with CAD in uremia patient are not clear.We aimed to assess HDL electronegativity and various properties of HDL in uremia patients and investigate whether electronegative HDL is a risk factor for CAD in these individuals. MethodsHDL from 60 uremia patients and 43 healthy controls was separated into 5 subfractions (H1H5) with increasing electronegativity by using anion-exchange chromatography. Lipoprotein content was analyzed by gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry. HDL anti-oxidant, anti-apoptosis and cholesterol efflux activities were examined by fluorescence-based assays. ResultsThe percentage of H5 HDL (H5%) was significantly higher in uremia patients than in controls (p < 0.001). The concentration of apolipoprotein (Apo) AI was lower and apolipoprotein modifications were more prevalent in uremia HDL subfractions than in control HDL subfractions. Carbamylation of ApoAI and ApoCIII was increased in more electronegative HDL subfractions from uremia patients. Anti-oxidant activity, anti-apoptotic activity, and cholesterol efflux capability were reduced in HDL subfractions from uremia patients when compared with control HDL subfractions. Multiple logistic regression analysis showed that H5% was associated with CAD risk in uremia patients. ConclusionsIn HDL of uremia patients, increased electronegativity is accompanied by compositional changes and impaired function. Our findings indicate that increased H5% is associated with increased CAD risk in uremia patients.

Abstract 553: Scavenging Reactive Aldehydes With 5'-o-pentyl-pyridoxamine (PPM) Improves HDL Function and Reduces Atherosclerosis in Ldlr Deficient Mice

Background: Lipid peroxidation products impair the cholesterol efflux capacity of high-density lipoprotein (HDL) and contribute to the development of atherosclerosis. The effect of inhibition of HDL dysfunction by scavengers on HDL function and whether scavenging reactive aldehydes with PPM protects against the development of atherosclerosis was examined. Methods and Results: HDL of familial hypercholesterolemia (FH) subjects have impaired ability to promote cholesterol efflux and FH-HDL contain 5-fold more malondialdehyde adducts (MDA) than control HDL. In vitro studies revealed that reactive aldehyde MDA crosslinks apolipoprotein AI (apoAI) and impairs the ability of HDL to promote cholesterol efflux from Apoe -/- macrophages. 5'-O-pentyl-pyridoxamine (PPM), a potent scavenger of reactive aldehydes, abolished MDA-mediated crosslinking of apoA-I in HDL by 80 % (P&lt;0.05). PPM prevents the reduction in cholesterol efflux capacity of MDA treated HDL in Apoe-/- macrophages. Furthermore, PPM significantly improved the cholesterol efflux capacity of HDL from Ldlr -/- mice fed a Western diet (WD) for 16 weeks (P&lt;0.05), indicating that PPM protects HDL from modifications by reactive aldehydes and maintains HDL function in vivo. Importantly, administration of 1 mg/mL of the reactive aldehyde scavenger PPM, versus 1 mg/mL of the nonreactive analogue PPO, to Ldlr -/- mice consuming a WD for 16 weeks reduced the extent of proximal aortic atherosclerosis by 45% (P&lt;0.05). Immunohistochemistry studies revealed that PPM reduced the macrophage content and the number of TUNEL positive cells by 55% (P&lt;0.05) and by 60% (P&lt;0.01) in advanced atherosclerotic lesions of Ldlr -/- mice, respectively. In addition, the necrotic core area was reduced by 52% (P&lt;0.05) in advanced atherosclerotic lesions in Ldlr -/- mice treated with PPM compared to the control group. Conclusions: Treatment with PPM, a reactive aldehyde scavenger: 1) inhibits MDA-ApoA1 adduct formation thereby preserving HDL cholesterol efflux capacity in Ldlr -/- mice; 2) reduces the number of apoptotic cells in atherosclerotic lesions and the necrotic core area in lesions of Ldlr -/- mice. These results support the therapeutic potential of PPM in the treatment of atherosclerotic cardiovascular disease.

Serum amyloid A enrichment impairs the anti-inflammatory ability of HDL from diabetic nephropathy patients

AimsImpaired anti-inflammatory ability of high-density lipoprotein (HDL) has been demonstrated in patients with type-2 diabetes mellitus (T2DM). However, whether HDL from patients with diabetic nephropathy (DN) suffers additional damage remains unknown. This study compared the anti-inflammatory capacities of HDL from healthy controls, T2DM patients with normal renal function, and T2DM patients with DN. Materials and methodsHDL was isolated from healthy controls (n=33) and T2DM patients with normal renal function (n=21), chronic kidney disease (CKD) (n=27), and end-stage renal disease (ESRD) (n=27). Human peripheral blood mononuclear cells (PBMCs) from healthy volunteers were pretreated with HDL (100μg/mL) for 1h, then incubated with lipopolysaccharide (LPS) (50ng/mL) for 24h. The anti-inflammatory ability of HDL was measured as the secretion of TNF-α in LPS-activated monocytes. ResultsThe anti-inflammatory ability of HDL was gradually impaired as kidney function declined. Serum amyloid A (SAA) concentration in HDLDN significantly increased and was positively correlated with the impaired anti-inflammatory ability of HDL (Pearson r=0.315, P=0.006). Furthermore, HDL supplemented with SAA significantly increased TNF-α release from PBMCs compared with that from control HDL. ConclusionsThese findings identified an impaired anti-inflammatory capacity of HDL from DN patients, which might be attributable to SAA enrichment.

Advanced glycation end products affect cholesterol homeostasis by impairing ABCA1 expression on macrophages.

Reverse cholesterol transport (RCT), which is intimately linked to high-density lipoproteins (HDLs), plays a key role in cholesterol homeostasis and the prevention of atherosclerosis. The goal of the present study was to investigate the effect of aging and advanced glycation end products (AGEs) on RCT as well as on other factors that may affect the antiatherogenic property of HDLs. The transfer of macrophage-derived cholesterol to the plasma and liver and then to the feces for elimination was significantly lower in aged mice than in young mice. Chronic injection of d -galactose (D-gal) or AGEs also significantly reduced RCT (65.3% reduction in [3H]cholesterol levels in the plasma of D-gal-treated mice after 48 h compared with control mice, P < 0.01). The injection of both D-gal and aminoguanidine hydrochloride increased [3H]cholesterol levels in the plasma, although the levels were lower than those of control mice. The in vitro incubation of HDLs with dicarbonyl compounds increased the carbonyl and conjugated diene content of HDLs and significantly reduced PON1 paraoxonase activity (87.4% lower than control HDLs, P < 0.0001). Treating J774A.1 macrophages with glycated fetal bovine serum increased carbonyl formation (39.5% increase, P < 0.003) and reduced ABCA1 protein expression and the capacity of macrophages to liberate cholesterol (69.1% decrease, P < 0.0001). Our results showed, for the first time, that RCT is altered with aging and that AGEs contribute significantly to this alteration.

Depletion in LpA-I:A-II particles enhances HDL-mediated endothelial protection in familial LCAT deficiency

The aim of this study was to evaluate the vasoprotective effects of HDL isolated from carriers of LCAT deficiency, which are characterized by a selective depletion of LpA-I:A-II particles and predominance of preβ migrating HDL. HDLs were isolated from LCAT-deficient carriers and tested in vitro for their capacity to promote NO production and to inhibit vascular cell adhesion molecule-1 (VCAM-1) expression in cultured endothelial cells. HDLs from carriers were more effective than control HDLs in promoting eNOS activation with a gene-dose-dependent effect (PTrend = 0.048). As a consequence, NO production induced by HDL from carriers was significantly higher than that promoted by control HDL (1.63 ± 0.24-fold vs. 1.34 ± 0.07-fold, P= 0.031). HDLs from carriers were also more effective than control HDLs in inhibiting the expression of VCAM-1 (homozygotes, 65.0 ± 8.6%; heterozygotes, 53.1 ± 7.2%; controls, 44.4 ± 4.1%; PTrend = 0.0003). The increased efficiency of carrier HDL was likely due to the depletion in LpA-I:A-II particles. The in vitro findings might explain why carriers of LCAT deficiency showed flow-mediated vasodilation and plasma-soluble cell adhesion molecule concentrations comparable to controls, despite low HDL-cholesterol levels. These results indicate that selective depletion of apoA-II-containing HDL, as observed in carriers of LCAT deficiency, leads to an increased capacity of HDL to stimulate endothelial NO production, suggesting that changes in HDL apolipoprotein composition may be the target of therapeutic interventions designed to improve HDL functionality.

Abstract 208: Isolevuglandin, a Highly Reactive γ-ketoaldehyde Formed from the Isoprostane Pathway, Induces Deleterious Structural and Functional Consequences to High-density Lipoprotein

Recent evidence suggest that cardiovascular disease (CVD) risk depends on levels of functional HDL particles, not HDL-cholesterol. In CVD, increased oxidative stress generates reactive lipid species that alter HDL function. Isolevuglandins (isoLGs), generated in parallel to isoprostanes, are extremely reactive to lysine residues of proteins and headgroups of phosphatidylethanolamine (PE). Importantly, IsoLG protein and PE adducts are elevated in atherosclerosis. Recently, our group observed a 42% reduction of atherosclerotic lesion size when salicylamine (SAM), a small molecule scavenger of reactive dicarbonyls including IsoLG, was administered to LDLr -/- mice. Little is known about the consequences of IsoLG to HDL function. The aim of this study is to compare effects of IsoLG on apolipoprotein crosslinking, morphology and size of HDL to its functions: cholesterol efflux, apoA-I exchange and anti-inflammation. Human HDL was incubated overnight at 37°C with IsoLG. Thioglycolate-induced intraperitoneal macrophages were harvested from apoE -/- mice. IsoLG crosslinked structural apolipoproteins, apoA-I and apoA-II, starting at 0.3 mol IsoLG per mol apoA-I (0.3 eq). HDL modified with 3 eq IsoLG formed subpopulations of two distinct sizes, 6-13 nm and 16-23 nm. A 40.6±0.04% decrease in 3 H-cholesterol efflux from macrophages was observed at 1 eq IsoLG compared to unmodified control HDL. At this IsoLG concentration, HDL-ApoA-I exchange was reduced (P&lt;0.01, n=4), from 47.4±2.8% with control HDL to only 24.8±5.8%, suggesting that IsoLG inhibited apoA-I from disassociating from HDL to interact with ABCA1. Intriguingly, IsoLG inhibited HDL’s protection against LPS-stimulated inflammatory response in macrophages at 0.03 eq as shown by IL-1β and TNFα mRNA expression comparable to LPS alone. At 0.1 eq IsoLG, HDL becomes pro-inflammatory, as indicated by a 927±309% increase in IL-1β mRNA expression (P&lt;0.001). Unlike cholesterol efflux, these effects occurred independent of HDL apolipoprotein crosslinking. We report a novel pathway by which HDL becomes dysfunctional, by mechanisms involving IsoLG-mediated alterations of HDL proteins and structure. Future studies will pinpoint how IsoLG modifies HDL proteins (or lipids) to alter its function.

Abstract 576: Salicylamine, A γ-ketoaldehyde Scavenger, Improves HDL Function and Reduces Atherosclerosis in Apoe Deficient Mice

Background: Lipid peroxidation products impair the cholesterol efflux capacity of high-density lipoprotein (HDL) and promote the development of atherosclerosis. The impact of inhibition of malondialdehyde (MDA)-HDL adduct formation by scavengers on HDL function and whether small molecule aldehyde scavengers protect against the development of atherosclerosis was examined. Methods and Results: Western blot analysis of ApoAI revealed that the amount of ApoAI crosslinking increased with MDA concentration. In the presence of LPS, MDA-HDL (HDL modified by 1mM MDA) versus control HDL stimulated 2- and 1.8-fold more expression of TNF-α and IL-1β in Apoe-/- macrophages demonstrating that MDA-HDL has reduced anti-inflammatory function. HDL-mediated macrophage cholesterol efflux was decreased by ~ 42%, 55%, 70%, and 80%, respectively, for HDL modified with 0.125 mM, 0.25 mM, 0.5 mM, and 1mM MDA, demonstrating that MDA modification of HDL affects its cholesterol efflux capacity in a dose dependent manner. Analysis by Western blot demonstrated that 5mM of salicylamine (SAM) and 5mM of pentylpyridoxamine (PPM), γ-ketoaldehyde scavengers, attenuated MDA mediated crosslinking of apoA-I in HDL (molar ratio of MDA and HDL is 1:5) by 60% and 80 % (P&lt;0.05), respectively. Both SAM and PPM maintained the cholesterol efflux capacity of MDA treated HDL in Apoe-/- macrophages. In addition, pretreatment of LDL with SAM prevented MDA-ApoB adduct formation, and compared to incubation with LDL containing MDA-ApoB adducts, SAM treatment resulted in 57% less cholesterol accumulation in J774 macrophages. Importantly, administration of the ketoaldehyde scavenger, SAM, versus the nonreactive analogue, 4-SAM, to Apoe-/- mice consuming a Western diet for 16 weeks reduced the extent of proximal aortic atherosclerosis by 28% (P&lt;0.05). Conclusions: Treatment with salicylamine, a γ-ketoaldehyde scavenger: 1) inhibits MDA-ApoA1 adduct formation thereby preserving HDL cholesterol efflux capacity; 2) prevents MDA-apoB100 formation resulting in less macrophage cholesterol accumulation; 3) reduces atherosclerosis in Apoe -/- mice. These results support the therapeutic potential of salicylamine in the treatment of atherosclerotic cardiovascular disease.

High density lipoprotein (HDL) particles from end-stage renal disease patients are defective in promoting reverse cholesterol transport

Atherosclerotic cardiovascular disease (CVD) represents the largest cause of mortality in end-stage renal disease (ESRD). CVD in ESRD is not explained by classical CVD risk factors such as HDL cholesterol mass levels making functional alterations of lipoproteins conceivable. HDL functions in atheroprotection by promoting reverse cholesterol transport (RCT), comprising cholesterol efflux from macrophage foam cells, uptake into hepatocytes and final excretion into the feces. ESRD-HDL (n = 15) were compared to healthy control HDL (n = 15) for their capacity to promote in vitro (i) cholesterol efflux from THP-1 macrophage foam cells and (ii) SR-BI-mediated selective uptake into ldla[SR-BI] cells as well as (iii) in vivo RCT. Compared with HDL from controls, ESRD-HDL displayed a significant reduction in mediating cholesterol efflux (p < 0.001) and SR-BI-mediated selective uptake (p < 0.01), two key steps in RCT. Consistently, also the in vivo capacity of ESRD-HDL to promote RCT when infused into wild-type mice was significantly impaired (p < 0.01). In vitro oxidation of HDL from healthy controls with hypochloric acid was able to fully mimic the impaired biological activities of ESRD-HDL. In conclusion, we demonstrate that HDL from ESRD patients is dysfunctional in key steps as well as overall RCT, likely due to oxidative modification.