The HDL Proteome Watch: Compilation of studies leads to new insights on HDL function

Background: Cholesterol efflux is an important mechanism by which high-density lipoproteins (HDLs) protect against cardiovascular disease. As peripheral artery disease (PAD) is associated with high mortality rates, mainly due to cardiovascular causes, we investigated whether cholesterol efflux capacity (CEC) of apolipoprotein B (apoB)-depleted plasma, a widely used surrogate of HDL function, may serve as a predictive marker for mortality in this patient population. Methods: In this prospective single-center study (median follow-up time: 9.3 years), apoB-containing lipoproteins were precipitated from plasma of 95 patients with PAD and incubated with J744-macrophages, which were loaded with radiolabeled cholesterol. CEC was defined as the fractional radiolabel released during 4 h of incubation. Results: Baseline CEC was lower in PAD patients that currently smoked (p = 0.015) and had a history of myocardial infarction (p = 0.011). Moreover, CEC showed a significant correlation with HDL-cholesterol (p = 0.003) and apolipoprotein A-I levels (p = 0.001) as well as the ankle-brachial index (ABI, p = 0.018). However, CEC did not differ between survivors and non-survivors. Neither revealed Kaplan–Meier and Cox regression analyses any significant association of CEC with all-cause mortality rates. Conclusion: Taken together, CEC is associated with ABI but does not predict all-cause mortality in patients with PAD.

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Rationale and design of the expanded combination of evolocumab plus empagliflozin in diabetes: EXCEED-BHS3 trial

Therapeutic Advances in Chronic Disease ◽

10.1177/2040622320959248 ◽

2020 ◽

Vol 11 ◽

pp. 204062232095924

Author(s):

Ikaro Breder ◽

Jessica Cunha Breder ◽

Isabella Bonilha ◽

Daniel B. Munhoz ◽

Sheila T. Kimura Medorima ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Open Label ◽

Lipoprotein Subfractions ◽

Regular Treatment ◽

Hdl Function ◽

Cell Adhesion Molecule 1

Background: Patients with type 2 diabetes mellitus (T2DM) remain at increased cardiovascular residual risk and endothelial dysfunction, even after optimizing metabolic control and treatment by sodium-glucose-2 transporter inhibitors (SGLT2-is). The present study was based on the hypothesis that proprotein convertase subtilisin/kexin 9 inhibitor (PCSK9i) therapy may mitigate endothelial dysfunction in T2DM patients who are on regular treatment by SGLT2-i. Methods: The EXCEED-BHS3 is a prospective, single-center, investigator-blinded, open-label, randomized clinical trial. Participants ( n = 110) will be randomized (1:1) to either empagliflozin 25 mg/day alone or empagliflozin 25 mg/day plus evolocumab 140 mg every 2 weeks in addition to optimal medical care. The primary endpoint was defined as the change in the 1-min flow-mediated dilation (FMD) after 16 weeks of treatment. The secondary endpoint is the FMD change after ischemia/reperfusion injury protocol (reserve FMD) after 16 weeks of treatment. Exploratory outcomes comprise the change in FMD and reserve FMD after 8 weeks of treatment and the change after 16 weeks of treatment in the following parameters: plasma levels of nitric oxide, vascular cell adhesion molecule-1 and isoprostane, high-density lipoprotein (HDL) and low-density lipoprotein subfractions profile, HDL function, blood pressure, body mass index, waist circumference and adipokines. Conclusion: This will be the first study to evaluate the add-on effect of PCSK9i on endothelial function of T2DM patients under regular use of empagliflozin. Trial registration: ClinicalTrials.gov identifier: NCT03932721

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Effects of cross-link breakers, glycation inhibitors and insulin sensitisers on HDL function and the non-enzymatic glycation of apolipoprotein A-I

Diabetologia ◽

10.1007/s00125-008-0986-z ◽

2008 ◽

Vol 51 (6) ◽

pp. 1008-1017 ◽

Cited By ~ 18

Author(s):

E. Nobécourt ◽

J. Zeng ◽

M. J. Davies ◽

B. E. Brown ◽

S. Yadav ◽

...

Keyword(s):

Cross Link ◽

Hdl Function ◽

Apolipoprotein A

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Abstract 631: Proteomic Characterization of Apolipoprotein A-II Defined Subfractions of Human High Density Lipoproteins

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.631 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Scott E Street ◽

John T Melchior ◽

Amy S Shah ◽

W. S Davidson

Keyword(s):

Physiological Function ◽

Critical Role ◽

Size Composition ◽

High Density ◽

Lipid Homeostasis ◽

High Density Lipoproteins ◽

Phospholipid Content ◽

Hdl Function ◽

Apolipoprotein A

High-density lipoproteins (HDL) play a critical role in lipid transport and vascular lipid homeostasis. HDL is heterogeneous, with particles varying in size, composition, and functionality. Proteomic studies have shown that HDL can host as many as 94 different proteins which can segregate into distinct subclasses. The two major apolipoproteins (apo)A-I and apoA-II account for 70% and 15-20%, respectively of HDL total protein. We hypothesized that the presence or absence of apoA-II can affect the binding of other proteins thus influencing HDL function. Immunoaffinity chromatography was used to isolate particles containing both apoA-I and apoA-II (LpA-I/LpA-II) and those with apoA-I with no apoA-II (LpA-I). These were isolated from both i ) total HDL isolated by ultracentrifugation (UC) and ii ) directly from plasma. The proteomic fingerprint of each population was determined by mass spectrometry. Within both populations, 54 total proteins were identified in UC isolated HDL compared to 98 proteins in particles isolated directly from plasma. In the UC isolated HDL, LpA-I/A-II particles contained 39 proteins compared to LpA-I particles which contained about 30. Interestingly, the opposite was true in particles isolated from plasma where upwards of 77 proteins on LpA-I/A-II particles were identified compared to LpA-I particles where 98 proteins were identified. Limited tryptic digestion experiments showed that LpA-I/A-II were more prone to proteolysis compared to LpA-I. Additionally, we found that LpA-I/A-II exhibited an increased capacity to efflux cholesterol from cultured macrophages (normalized by phospholipid content) suggesting a protein mediated difference in HDL functionality. Taken together, these results suggest the proteomic fingerprint of HDL subpopulations is heavily influenced by the method of isolation and that the proteomic pattern on HDL influences the physiological function of the particle.

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Abstract 110: The Separation of Serum Amyloid A from HDL is Mediated by Heparan Sulfate Through Histidine Dependent Interactions: HDL Function is Enhanced but Amyloid-Fibrils may be the “Price to Pay”¼

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.35.suppl_1.110 ◽

2015 ◽

Vol 35 (suppl_1) ◽

Author(s):

John B Ancsin ◽

Kim Munro ◽

Shui-Pang Tam ◽

Michael H Davidson

Keyword(s):

Heparan Sulfate ◽

Serum Amyloid A ◽

Amyloid Fibrils ◽

3D Structure ◽

Serum Amyloid ◽

Acidic Ph ◽

Heparin Binding ◽

Additional Time ◽

Amyloid A ◽

Hdl Function

Serum amyloid A (SAA) is an acute-phase protein that circulates bound to high density lipoprotein (HDL) and can influence HDL function as part of a poorly understood defense re-sponse to tissue trauma or infection. We have previously demonstrated that under mildly acidic pH the glycosaminoglycans, heparan sulfate (HS) and heparin can interact with HDL-SAA and cause SAA to dissociate from HDL. This remodeling improves HDL functionality but also predisposes SAA to form AA-amyloid fibrils. In this study we explore some potential pathophysiological conditions in vitro that could influence this HS/HDL-SAA remodeling process and the fate of SAA in vivo. SAA’s binding affinity for heparin was found to be enhanced by acidic pH and low concentrations of urea. The heparin dependent remodeling of HDL-SAA was promoted by the partial denaturation of HDL-SAA. Moreover, HDL-SAA remodeling was observed to follow a strict SAA:heparin stoichiometry and could be partially inhibited with a short heparin oligosaccharide of 8-sugar units. Evidence is also presented that once dissociated from HDL, SAA requires additional time to organize into Triton x-100 resistant amyloid-like structures. Circular dichroism spectroscopic analysis and in silico modeling of SAA’s ionizable residues highlights the importance of the histidine-36 within a highly conserved, pH-sensitive HS-binding site (HSBS-pH). A peptide containing the HSBS-pH sequence was demonstrated to have AA-amyloid seeding activity in a cell culture system. The recent determination of the 3D structure for human SAA1.1 has allowed the opportunity to re-assess and validate the HS/heparin binding sequences that had previously been identified biochemically with short synthetic peptides. We postulate that the dissociation of SAA from HDL takes place during the retro-endocytosis of HDL-SAA and is an important aspect of SAA function not previously appreciated.

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Abstract P193: Increased High Density Lipoprotein Cholesterol:ApolipoproteinA1 Ratio is Associated with Less Progression of Coronary Atherosclerosis in Statin-Treated Patients

Circulation ◽

10.1161/circ.125.suppl_10.ap193 ◽

2012 ◽

Vol 125 (suppl_10) ◽

Author(s):

Preethi Mani ◽

Kiyoko Uno ◽

Julie Thornton ◽

Stephen Nicholls

Keyword(s):

Coronary Atherosclerosis ◽

Coronary Plaque ◽

Cholesterol Content ◽

Favorable Effect ◽

Plaque Burden ◽

P Value ◽

Plaque Progression ◽

Coronary Syndrome ◽

Hdl Function ◽

Atheroma Volume

Background HDL cholesterol (HDL-C) and apolipoprotein AI (apoAI) levels are inversely related to adverse cardiovascular outcome. Associations between these HDL related measures and their ratio with coronary plaque progression have not been studied. It has been proposed that increasing HDL particle cholesterol content impairs HDL function, but impact on disease progression is unknown. We hypothesize that all HDL related measures are inversely associated with coronary plaque progression. Methods Retrospective analysis was performed of 1528 statin treated patients with angiographic CAD who had serial evaluation of atheroma burden with intravascular ultrasound. Relationships between achieved levels of HDL related measures with clinical characteristics and changes in plaque burden were determined. Results Strong correlation between HDL-C and apoAI (r=0.73, p<0.0001) was noted. Patients with highest levels of HDL-C:apoAI were more likely to be female, black, and have lower BMI and less likely to be smokers or have previous revascularization (all p<0.001) or acute coronary syndrome (p=0.013). HDL-C, apoAI, and HDL-C:apoAI demonstrated negative correlation with change in total atheroma volume (p<0.01). For HDL-C:apoAI and HDL-C, increasing tertiles of achieved levels were associated with a linear benefit in slowing progression. For apoAI, a nonlinear association was seen, with similar benefit on progression in the middle and upper tertiles ( Table ). There was no statistical interaction for heterogeneity between HDL-C:apoAI and atheroma burden based on achieved levels of HDL-C (p=0.581). Change in IVUS Measures By Tertiles of Achieved HDL-related Parameters Percent Atheroma Volume Parameter T1 T2 T3 P Value HDL-C 0.58±0.27 0.26±0.27 0.11±0.27 0.012 ApoAI 0.28±0.26 −0.04±0.26 −0.08±0.26 0.10 HDL-C:ApoAI 0.22±0.27 0.13±0.27 −0.27±0.27 0.021 Total Atheroma Volume Parameter T1 T2 T3 P Value HDL-C −2.46±2.21 −4.18±2.20 −5.31±2.20 0.035 ApoAI −4.94±2.13 −6.30±2.13 −7.40±2.13 0.135 HDL-C:ApoAI −4.59±2.25 −6.38±2.24 −8.07±2.26 0.022 Conclusions Increase in all HDL related measures was associated with less progression of coronary atherosclerosis. Association of higher HDL-C:ApoAI with favorable effect on plaque progression at all levels of HDL-C suggests intact HDL functionality of larger cholesterol rich particles. Interventions that increase HDL particle cholesterol content, such as CETP inhibitors, may thus have beneficial effect at the artery wall.

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Abstract W MP38: Apolipoprotein A-I (ApoA-I) Mimetic Peptide, D-4F, Regulates miRNA Expression and Improves Functional Outcome after Stroke in Diabetic Rats

Stroke ◽

10.1161/str.45.suppl_1.wmp38 ◽

2014 ◽

Vol 45 (suppl_1) ◽

Author(s):

Ruizhuo Ning ◽

Michael Chopp ◽

Alex Zacharek ◽

Tao Yan ◽

Cynthia Roberts ◽

...

Keyword(s):

Functional Outcome ◽

Mirna Expression ◽

Target Gene ◽

M2 Macrophage ◽

Lesion Volume ◽

Ischemic Brain ◽

Mimetic Peptide ◽

Hdl Function ◽

Functional Benefit ◽

Gene And Protein Expression

Introduction: Diabetes mellitus (DM) in patients is associated with low high-density lipoprotein cholesterol (HDL-C) and impairment of the anti-oxidative capacity of HDL-C. Several miRNAs have been identified as having a physiological role in tissues in which diabetes complications occur. D-4F is an economical ApoA-I mimetic peptide which increases HDL function. We therefore investigated the therapeutic effect and underlying mechanisms of D-4F treatment of stroke induced functional benefit effects in type one DM (T1DM) rats. Methods: T1DM was induced in Wistar rats by streptozotocin (60mg/kg, ip) .Subsequently they were subjected to embolic middle cerebral artery occlusion. D-4F (10 mg/kg i.p.) was administered at 2h, 24h and 48h after stroke. Functional outcomes, brain blood barrier (BBB) leakage and lesion volume were evaluated. Results: D-4F treatment of stroke in T1DM rats significantly decreased Evans Blue dye leakage (15.85±1.52 ng/mg vs contro: 30.57± 5.88 ng/mg) and significantly improved functional outcome compared to non-treatment T1DM-control. D-4F treatment significantly increased miR-124a and miR-181c, but decreased miR-200b expression in the ischemic brain. Using laser capture, D-4F also significantly increased ischemic brain endothelial cell miR-126 expression compared to non-treatment control. In addition, D-4F treatment significantly decreased miR-181c target gene tumor necrosis factor-a (TNF-a), and miR-124a target gene monocyte chemoattractant protein-1 (MCP1) expression. D-4F also decreased proinflammatory nuclear NFkB (26.07±3.17 vs 37.43±3.47), Toll-like receptor 4 (TLR4, 7.26±0.69 vs 10.5±1.2), matrix metalloproteinase 9 (MMP9, 0.16±0.04 vs 0.48±0.09) expression, and increased CD163 (M2 macrophage marker, 120.98±8.13 vs 85.02± 9.47) number compared to T1DM-MCAo control rats. Conclusion: D-4F treatment of stroke in T1DM rats regulates miRNA expression and their target gene and protein expression and induces anti-inflammatory effects and promotes M2 macrophage polarization which may contribute to D-4F decreased BBB leakage and induced functional benefit effects after stroke in T1DM rats.

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Abstract 1696: Compound RVX-208 Modulates HDL-C Levels and Function in Non-human Primates and in Early (phase I) Human Trials

Circulation ◽

10.1161/circ.118.suppl_18.s_371-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Larbi Krimbou ◽

Ravi Jahagirdar ◽

Dana Bailey ◽

Anouar Hafiane ◽

Isabelle Ruel ◽

...

Keyword(s):

Oral Administration ◽

Healthy Volunteers ◽

Size Distribution ◽

Cholesterol Efflux ◽

Oral Absorption ◽

Therapeutic Potential ◽

Human Study ◽

Treated Group ◽

Atherosclerotic Cardiovascular Disease ◽

Hdl Function

The novel compound RVX-208 is a small molecule that upregulates the gene expression of apoA-I and raises HDL-C in non-human primates. Here, we examined the effects of oral administration of RVX-208 on serum apoA-I and HDL-C levels , HDL size distribution, and HDL function. African green monkeys received RVX-208 (7.5, 15 and 30 mg/kg; twice daily and 60 mg/kg; once daily) or vehicle control for 28, 42, and 63 days. We report that RVX-208 chronic treatment resulted in a highly significant increase in the average of serum apoA-I and HDL-C levels (57% and 92%, respectively). Interestingly, RVX-208 treatment modified the distribution of HDL particle size causing a significant increase in preβ1-LpA-I and larger α1-LpA-I species. The ability of serum to promote cholesterol efflux via ABCA1, ABCG1 or SR-BI-dependent pathways in a cell culture model was significantly increased by RVX-208. The phase Ia safety and pharmacokinetic human study comprised of a total of 80 subjects. In the multiple ascending dose arm, 24 participants were randomly assigned to 3 cohorts of 8 healthy volunteers (6 active and 2 placebo), and received oral administration of RVX-208 at 2, 3 and 8 mg/kg per day or placebo for 7 days. The compound was well tolerated and had good oral absorption meeting the objectives of safety and pharmacokinetics. ApoA-I, HDL-C, HDL size distribution and ABCA1-dependent cholesterol efflux were assessed at days 1 (predose) and 7. The percent change from baseline to day 7 for apoA-I was 11% higher (P = 0.03) in the RVX-208 treated participants compared to placebo. Interestingly, preβ1-LpA-I change was 30% (P = 0.02) higher in the actively treated group and was found to strongly correlate with increased apoA-I levels (R2 = 0.72). Furthermore, ABCA1-dependent cholesterol efflux change was 10% higher (P = 0.03) and was found to correlate with increased preβ1-LpA-I . Taken together, these pharmacodynamic data from human healthy volunteers show consistent trends in apoA-I production and HDL functionality, supporting the findings in the African green monkey. Further investigation of the effect of RVX-208 on the HDL metabolic pathway is ongoing in humans and animals to establish the mechanisms of action and therapeutic potential in treating atherosclerotic cardiovascular disease.

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