Synthesis of reconstituted high density lipoprotein (rHDL) containing apoA-I and apoC-III: the functional role of apoC-III in rHDL

The Pleiotropic Effects of Lipid-Modifying Interventions: Exploring Traditional and Emerging Hypolipidemic Therapies

Atherosclerotic cardiovascular disease poses a significant global health issue, with dyslipidemia standing out as a major risk factor. In recent decades, lipid-lowering therapies have evolved significantly, with statins emerging as the cornerstone treatment. These interventions play a crucial role in both primary and secondary prevention by effectively reducing cardiovascular risk through lipid profile enhancements. Beyond their primary lipid-lowering effects, extensive research indicates that these therapies exhibit pleiotropic actions, offering additional health benefits. These include anti-inflammatory properties, improvements in vascular health and glucose metabolism, and potential implications in cancer management. While statins and ezetimibe have been extensively studied, newer lipid-lowering agents also demonstrate similar pleiotropic effects, even in the absence of direct cardiovascular benefits. This narrative review explores the diverse pleiotropic properties of lipid-modifying therapies, emphasizing their non-lipid effects that contribute to reducing cardiovascular burden and exploring emerging benefits for non-cardiovascular conditions. Mechanistic insights into these actions are discussed alongside their potential therapeutic implications.

Synergistic Anti-Inflammatory Activity of Apolipoprotein A-I and CIGB-258 in Reconstituted High-Density Lipoproteins (rHDL) against Acute Toxicity of Carboxymethyllysine in Zebrafish and Its Embryo

CIGB-258 is a 3 kDa altered peptide ligand from heat shock protein (HSP) 60 that exhibits anti-inflammatory activity against the acute toxicity of carboxymethyllysine (CML) with antioxidant and anti-glycation activities via protection of high-density lipoprotein (HDL) and apolipoprotein A-I (apoA-I). It is necessary to test a synergistic interaction between apoA-I and CIGB-258 in reconstituted high-density lipoproteins (rHDL). Several rHDLs were synthesized containing palmitoyloleoyl phosphatidylcholine (POPC), cholesterol, apoA-I, and CIGB-258 at molar ratios of 95:5:1:0, 95:5:1:0.1, 95:5:1:0.5, and 95:5:1:1 for rHDL-(1:0), rHDL-(1:0.1), rHDL-(1:0.5), and rHDL-(1:1), respectively. As the CIGB-258 content in rHDL was increased, the particle size of rHDL was 1.4-times higher than rHDL-(1:0) to rHDL-(1:1), from 60 nm to 83 nm, respectively. As the CIGB-258 content was increased, the rHDL showed the most resistance to isothermal denaturation by a urea treatment, and rHDL-(1:1) exhibited the highest structural stability and the strongest antioxidant ability against LDL oxidation. Co-treatment of rHDL-(1:0), rHDL-(1:0.5), and rHDL-(1:1) resulted in up to 10%, 24%, and 34% inhibition of HDL glycation, inhibition of HDL glycation, which was caused by the CML, with protection of apoA-I. Microinjection of each rHDL into zebrafish embryos in the presence of CML showed that a higher CIGB-258 content in rHDL was associated with higher survivability with the least inflammation and apoptosis. Furthermore, an intraperitoneal injection of rHDL and CML showed that a higher CIGB-258 content in rHDL was also associated with higher survivability of zebrafish and faster recovery of swimming ability. The rHDL-(1:1) group showed the lowest triglyceride, AST, and ALT serum levels with the least production of interleukin-6, oxidized product, and neutrophil infiltration in hepatic tissue. In conclusion, CIGB-258 could bind well to phospholipids and cholesterol to stabilize apoA-I in the rHDL structure against denaturation stress and larger particle sizes. The rHDL containing CIGB-258 enhanced the in vitro antioxidant ability against LDL oxidation, the anti-glycation activity to protect HDL, and the in vivo anti-inflammatory activity against CML toxicity in zebrafish adults and embryos. Overall, incorporating apoA-I and CIGB-258 in rHDL resulted in a synergistic interaction to enhance the structural and functional correlations in a dose-dependent manner of CIGB-258.

The Impact of Aerobic Exercise on HDL Quantity and Quality: A Narrative Review

High-density lipoproteins comprise roughly 25-30% of the circulating proteins involved in the transport of lipids in circulation. These particles differ in size and lipid composition. Recent evidence suggests that the quality of HDL particles (which depends on shape, size and the composition of proteins and lipids determining HDL functionality) may be more important than their quantity. The functionality of HDL is mirrored by its cholesterol efflux activity, as well as its antioxidant (including the protection of LDL against oxidation), anti-inflammatory and antithrombotic properties. The results of many studies and meta-analyses imply the beneficial impact of aerobic exercise on HDL-C levels. Physical activity was found to be usually associated with an increase in HDL cholesterol and a decrease in LDL cholesterol and triglycerides. Exercise, apart from inducing quantitative alterations in serum lipids, exerts a beneficial impact on HDL particle maturation, composition and functionality. The Physical Activity Guidelines Advisory Committee Report underlined the importance of establishing a program recommending exercises that enable attainment of maximal advantage at the lowest level of risk. The aim of this manuscript is to review the impact of different types of aerobic exercise (various intensities and durations) on the level and quality of HDL.

Cuban Sugar Cane Wax Alcohol Exhibited Enhanced Antioxidant, Anti-Glycation and Anti-Inflammatory Activity in Reconstituted High-Density Lipoprotein (rHDL) with Improved Structural and Functional Correlations: Comparison of Various Policosanols

Policosanols from various sources, such as sugar cane, rice bran, and insects, have been marketed to prevent dyslipidemia, diabetes, and hypertension by increasing the blood high-density lipoproteins cholesterol (HDL-C) levels. On the other hand, there has been no study on how each policosanol influences the quality of HDL particles and their functionality. Reconstituted high-density lipoproteins (rHDLs) with apolipoprotein (apo) A-I and each policosanol were synthesized using the sodium cholate dialysis method to compare the policosanols in lipoprotein metabolism. Each rHDL was compared regarding the particle size and shape, antioxidant activity, and anti-inflammatory activity in vitro and in zebrafish embryos. This study compared four policosanols including one policosanol from Cuba (Raydel^® policosanol) and three policosanols from China (Xi'an Natural sugar cane, Xi'an Realin sugar cane, and Shaanxi rice bran). The synthesis of rHDLs with various policosanols (PCO) from Cuba or China using a molar ratio of 95:5:1:1 with palmitoyloleoyl phosphatidylcholine (POPC): free cholesterol (FC): apoA-I:PCO (wt:wt) showed that rHDL containing Cuban policosanol (rHDL-1) showed the largest particle size and the most distinct particle shape. The rHDL-1 showed a 23% larger particle diameter and increased apoA-I molecular weight with a 1.9 nm blue shift of the maximum wavelength fluorescence than rHDL alone (rHDL-0). Other rHDLs containing Chinese policosanols (rHDL-2, rHDL-3, and rHDL-4) showed similar particle sizes with an rHDL-0 and 1.1-1.3 nm blue shift of wavelength maximum fluorescence (WMF). Among all rHDLs, the rHDL-1 showed the strongest antioxidant ability to inhibit cupric ion-mediated LDL oxidation. The rHDL-1-treated LDL showed the most distinct band intensity and particle morphology compared with the other rHDLs. The rHDL-1 also exerted the highest anti-glycation activity to inhibit the fructose-mediated glycation of human HDL₂ with the protection of apoA-I from proteolytic degradation. At the same time, other rHDLs showed a loss of anti-glycation activity with severe degradation. A microinjection of each rHDL alone showed that rHDL-1 had the highest survivability of approximately 85 ± 3%, with the fastest developmental speed and morphology. In contrast, rHDL-3 showed the lowest survivability, around 71 ± 5%, with the slowest developmental speed. A microinjection of carboxymethyllysine (CML), a pro-inflammatory advanced glycated end product, into zebrafish embryos resulted in severe embryo death of approximately 30 ± 3% and developmental defects with the slowest developmental speed. On the other hand, the phosphate buffered saline (PBS)-injected embryo showed 83 ± 3% survivability. A co-injection of CML and each rHDL into adult zebrafish showed that rHDL-1 (Cuban policosanol) induced the highest survivability, around 85 ± 3%, while rHDL-0 showed 67 ± 7% survivability. In addition, rHDL-2, rHDL-3, and rHDL-4 showed 67 ± 5%, 62 ± 37, and 71 ± 6% survivability, respectively, with a slower developmental speed and morphology. In conclusion, Cuban policosanol showed the strongest ability to form rHDLs with the most distinct morphology and the largest size. The rHDL-containing Cuban policosanol (rHDL-1) showed the strongest antioxidant ability against LDL oxidation, anti-glycation activity to protect apoA-I from degradation, and the highest anti-inflammatory activity to protect embryo death under the presence of CML.

Human Serum Amyloid a Impaired Structural Stability of High-Density Lipoproteins (HDL) and Apolipoprotein (Apo) A-I and Exacerbated Glycation Susceptibility of ApoA-I and HDL

Human serum amyloid A (SAA) is an exchangeable apolipoprotein (apo) in high-density lipoprotein (HDL) that influences HDL quality and functionality, particularly in the acute phase of inflammation. On the other hand, the structural and functional correlations of HDL containing SAA and apoA-I have not been reported. The current study was designed to compare the change in HDL quality with increasing SAA content in the lipid-free and lipid-bound states in reconstituted HDL (rHDL). The expressed recombinant human SAA1 (13 kDa) was purified to at least 98% and characterized in the lipid-free and lipid-bound states with apoA-I. The dimyristoyl phosphatidylcholine (DMPC) binding ability of apoA-I was impaired severely by the addition of SAA, while SAA alone could not bind with DMPC. The recombinant human SAA1 was incorporated into the rHDL (molar ratio 95:5:1, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC): cholesterol: apoA-I) with various apoA-I:SAA molar ratios from 1:0 to 1:0.5, 1:1 and 1:2. With increasing SAA1 content, the rHDL particle size was reduced from 98 Å to 93 Å, and the α-helicity of apoA-I:SAA was decreased from 73% to 40% for (1:0) and (1:2), respectively. The wavelength maximum fluorescence (WMF) of tryptophan in rHDL was red-shifted from 339 nm to 345 nm for (1:0) and (1:2) of apoA-I:SAA, respectively, indicating that the addition of SAA to rHDL destabilized the secondary structure of apoA-I. Upon denaturation by urea treatment from 0 M to 8 M, SAA showed only a 3 nm red-shift in WMF, while apoA-I showed a 16 nm red-shift in WMF, indicating that SAA is resistant to denaturation and apoA-I had higher conformational flexibility than SAA. The glycation reaction of apoA-I in the presence of fructose was accelerated up to 1.8-fold by adding SAA in a dose-dependent manner than that of apoA-I alone. In conclusion, the incorporation of SAA in rHDL impaired the structural stability of apoA-I and exacerbated glycation of HDL and apoA-I.

Lipidomic Approaches to Study HDL Metabolism in Patients with Central Obesity Diagnosed with Metabolic Syndrome

The metabolic syndrome (MetS) is a cluster of cardiovascular risk factors characterised by central obesity, atherogenic dyslipidaemia, and changes in the circulating lipidome; the underlying mechanisms that lead to this lipid remodelling have only been partially elucidated. This study used an integrated "omics" approach (untargeted whole serum lipidomics, targeted proteomics, and lipoprotein lipidomics) to study lipoprotein remodelling and HDL composition in subjects with central obesity diagnosed with MetS (vs. controls). Compared with healthy subjects, MetS patients showed higher free fatty acids, diglycerides, phosphatidylcholines, and triglycerides, particularly those enriched in products of de novo lipogenesis. On the other hand, the "lysophosphatidylcholines to phosphatidylcholines" and "cholesteryl ester to free cholesterol" ratios were reduced, pointing to a lower activity of lecithin cholesterol acyltransferase (LCAT) in MetS; LCAT activity (directly measured and predicted by lipidomic ratios) was positively correlated with high-density lipoprotein cholesterol (HDL-C) and negatively correlated with body mass index (BMI) and insulin resistance. Moreover, many phosphatidylcholines and sphingomyelins were significantly lower in the HDL of MetS patients and strongly correlated with BMI and clinical metabolic parameters. These results suggest that MetS is associated with an impairment of phospholipid metabolism in HDL, partially led by LCAT, and associated with obesity and underlying insulin resistance. This study proposes a candidate strategy to use integrated "omics" approaches to gain mechanistic insights into lipoprotein remodelling, thus deepening the knowledge regarding the molecular basis of the association between MetS and atherosclerosis.

The Current Status of Research on High-Density Lipoproteins (HDL): A Paradigm Shift from HDL Quantity to HDL Quality and HDL Functionality

The quantity of high-density lipoproteins (HDL) is represented as the serum HDL-C concentration (mg/dL), while the HDL quality manifests as the diverse features of protein and lipid content, extent of oxidation, and extent of glycation. The HDL functionality represents several performance metrics of HDL, such as antioxidant, anti-inflammatory, and cholesterol efflux activities. The quantity and quality of HDL can change during one's lifetime, depending on infection, disease, and lifestyle, such as dietary habits, exercise, and smoking. The quantity of HDL can change according to age and gender, such as puberty, middle-aged symptoms, climacteric, and the menopause. HDL-C can decrease during disease states, such as acute infection, chronic inflammation, and autoimmune disease, while it can be increased by regular aerobic exercise and healthy food consumption. Generally, high HDL-C at the normal level is associated with good HDL quality and functionality. Nevertheless, high HDL quantity is not always accompanied by good HDL quality or functionality. The HDL quality concerns the morphology of the HDL, such as particle size, shape, and number. The HDL quality also depends on the composition of the HDL, such as apolipoproteins (apoA-I, apoA-II, apoC-III, serum amyloid A, and α-synuclein), cholesterol, and triglyceride. The HDL quality is also associated with the extent of HDL modification, such as glycation and oxidation, resulting in the multimerization of apoA-I, and the aggregation leads to amyloidogenesis. The HDL quality frequently determines the HDL functionality, which depends on the attached antioxidant enzyme activity, such as the paraoxonase and cholesterol efflux activity. Conventional HDL functionality is regression, the removal of cholesterol from atherosclerotic lesions, and the removal of oxidized species in low-density lipoproteins (LDL). Recently, HDL functionality was reported to expand the removal of β-amyloid plaque and inhibit α-synuclein aggregation in the brain to attenuate Alzheimer's disease and Parkinson's disease, respectively. More recently, HDL functionality has been associated with the susceptibility and recovery ability of coronavirus disease 2019 (COVID-19) by inhibiting the activity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The appearance of dysfunctional HDL is frequently associated with many acute infectious diseases and chronic aging-related diseases. An HDL can be a suitable biomarker to diagnose many diseases and their progression by monitoring the changes in its quantity and quality in terms of the antioxidant and anti-inflammatory abilities. An HDL can be a protein drug used for the removal of plaque and as a delivery vehicle for non-soluble drugs and genes. A dysfunctional HDL has poor HDL quality, such as a lower apoA-I content, lower antioxidant ability, smaller size, and ambiguous shape. The current review analyzes the recent advances in HDL quantity, quality, and functionality, depending on the health and disease state during one's lifetime.

Structural and Functional Changes of Reconstituted High-Density Lipoprotein (HDL) by Incorporation of α-synuclein: A Potent Antioxidant and Anti-Glycation Activity of α-synuclein and apoA-I in HDL at High Molar Ratio of α-synuclein

α-synuclein (α-syn) is a major culprit of Parkinson's disease (PD), although lipoprotein metabolism is very important in the pathogenesis of PD. α-syn was expressed and purified using the pET30a expression vector from an E. coli expression system to elucidate the physiological effects of α-syn on lipoprotein metabolism. The human α-syn protein (140 amino acids) with His-tag (8 amino acids) was expressed and purified to at least 95% purity. Isoelectric focusing gel electrophoresis showed that the isoelectric point (pI) of α-syn and apoA-I were pI = 4.5 and pI = 6.4, respectively. The lipid-free α-syn showed almost no phospholipid-binding ability, while apoA-I showed rapid binding ability with a half-time (T_1/2) = 8 ± 0.7 min. The α-syn and apoA-I could be incorporated into the reconstituted HDL (rHDL, molar ratio 95:5:1:1, palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC):cholesterol:apoA-I:α-syn with the production of larger particles (92 Å) than apoA-I-rHDL (86 and 78 Å) and α-syn-rHDL (65 Å). An rHDL containing both apoA-I and α-syn showed lower α-helicity around 45% with a red shift of the Trp wavelength maximum fluorescence (WMF) from 339 nm, while apoA-I-HDL showed 76% α-helicity and 337 nm of WMF. The denaturation by urea addition showed that the incorporation of α-syn in rHDL caused a larger increase in the WMF than apoA-I-rHDL, suggesting that the destabilization of the secondary structure of apoA-I by the addition of α-syn. On the other hand, the addition of α-syn induced two-times higher resistance to rHDL glycation at apoA-I:α-syn molar ratios of 1:1 and 1:2. Interestingly, low α-syn in rHDL concentrations, molar ratio of 1:0.5 (apoA-I:α-syn), did not prevent glycation with more multimerization of apoA-I. In the lipid-free and lipid-bound state, α-syn showed more potent antioxidant activity than apoA-I against cupric ion-mediated LDL oxidation. On the other hand, microinjection of α-syn (final 2 μM) resulted in 10% less survival of zebrafish embryos than apoA-I. A subcutaneous injection of α-syn (final 34 μM) resulted in less tail fin regeneration than apoA-I. Interestingly, incorporation of α-syn at a low molar ratio (apoA-I:α-syn, 1:0.5) in rHDL resulted destabilization of the secondary structure and impairment of apoA-I functionality via more oxidation and glycation. However, at a higher molar ratio of α-syn in rHDL (apoA-I:α-syn = 1:1 or 1:2) exhibited potent antioxidant and anti-glycation activity without aggregation. In conclusion, there might be a critical concentration of α-syn and apoA-I in HDL-like complex to prevent the aggregation of apoA-I via structural and functional enhancement.

Structural and Functional Impairments of Reconstituted High-Density Lipoprotein by Incorporation of Recombinant β-Amyloid42

Beta (β)-amyloid (Aβ) is a causative protein of Alzheimer’s disease (AD). In the pathogenesis of AD, the apolipoprotein (apo) A-I and high-density lipoprotein (HDL) metabolism is essential for the clearance of Aβ. In this study, recombinant Aβ42 was expressed and purified via the pET-30a expression vector and E.coli production system to elucidate the physiological effects of Aβ on HDL metabolism. The recombinant human Aβ protein (51 aa) was purified to at least 95% purity and characterized in either the lipid-free and lipid-bound states with apoA-I. Aβ was incorporated into the reconstituted HDL (rHDL) (molar ratio 95:5:1, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC):cholesterol:apoA-I) with various apoA-I:Aβ ratios from 1:0 to 1:0.5, 1:1 and 1:2. With an increasing molar ratio of Aβ, the α-helicity of apoA-I was decreased from 62% to 36% with a red shift of the Trp wavelength maximum fluorescence from 337 to 340 nm in apoA-I. The glycation reaction of apoA-I was accelerated further by the addition of Aβ. The treatment of fructose and Aβ caused more multimerization of apoA-I in the lipid-free state and in HDL. The phospholipid-binding ability of apoA-I was impaired severely by the addition of Aβ in a dose-dependent manner. The phagocytosis of LDL into macrophages was accelerated more by the presence of Aβ with the production of more oxidized species. Aβ severely impaired tissue regeneration, and a microinjection of Aβ enhanced embryotoxicity. In conclusion, the beneficial functions of apoA-I and HDL were severely impaired by the addition of Aβ via its detrimental effect on secondary structure. The impairment of HDL functionality occurred more synergistically by means of the co-addition of fructose and Aβ.

ApoE and apoC-III-defined HDL subtypes: a descriptive study of their lecithin cholesterol acyl transferase and cholesteryl ester transfer protein content and activity

Background

The functionality of high-density lipoproteins (HDL) is a better cardiovascular risk predictor than HDL concentrations. One of the key elements of HDL functionality is its apolipoprotein composition. Lecithin-cholesterol acyl transferase (LCAT) and cholesterol-ester transfer protein (CETP) are enzymes involved in HDL-mediated reverse cholesterol transport. This study assessed the concentration and activity of LCAT and CETP in HDL subspecies defined by their content of apolipoproteins E (apoE) and C-III (apoC-III) in humans.

Methods

Eighteen adults (ten women and eight men, mean age 55.6, BMI 26.9 Kg/m², HbA1c 5.4%) were studied. HDL from each participant were isolated and divided into four subspecies containing respectively: No apoE and no apoC-III (E-C-), apoE but not apoC-III (E + C-), apoC-III but no apoE (E-C+) and both apoE and apoC-III (E + C+). The concentration and enzymatic activity of LCAT and CETP were measured within each HDL subspecies using immunoenzymatic and fluorometric methods. Additionally, the size distribution of HDL in each apolipoprotein-defined fraction was determined using non-denaturing electrophoresis and anti-apoA-I western blotting.

Results

HDL without apoE or apoC-III was the predominant HDL subtype. The size distribution of HDL was very similar in all the four apolipoprotein-defined subtypes. LCAT was most abundant in E-C- HDL (3.58 mg/mL, 59.6% of plasma LCAT mass), while HDL with apoE or apoC-III had much less LCAT (19.8, 12.2 and 8.37% of plasma LCAT respectively for E + C-, E-C+ and E + C+). LCAT mass was lower in E + C- HDL relative to E-C- HDL, but LCAT activity was similar in both fractions, signaling a greater activity-to-mass ratio associated with the presence of apoE. Both CETP mass and CETP activity showed only slight variations across HDL subspecies. There was an inverse correlation between plasma LCAT activity and concentrations of both E-C+ pre-beta HDL (r = − 0.55, P = 0.017) and E-C- alpha 1 HDL (r = − 0.49, P = 0.041). Conversely, there was a direct correlation between plasma CETP activity and concentrations of E-C+ alpha 1 HDL (r = 0.52, P = 0.025).

Conclusions

The presence of apoE in small HDL is correlated with increased LCAT activity and esterification of plasma cholesterol. These results favor an interpretation that LCAT and apoE interact to enhance anti-atherogenic pathways of HDL.

Emerging evidences for the opposite role of apolipoprotein C3 and apolipoprotein A5 in lipid metabolism and coronary artery disease

Apolipoprotein C3 (apoC3) and apolipoprotein A5 (apoA5), encoded by APOA1/C3/A4/A5 gene cluster, are two critical regulators of plasma triglyceride (TG) metabolism. Deficiency of apoC3 or apoA5 led to significant decreased or increased plasma TG levels, respectively. Recent studies indicated apoC3 and apoA5 also played roles in plasma remnant cholesterol, high density lipoprotein (HDL) and hepatic TG metabolisms. Moreover, large scale population genetic studies indicated that loss of function mutations in APOC3 and APOA5 gene conferred decreased and increased risk of coronary artery disease (CAD), respectively. This manuscript mainly reviewed existing evidences suggesting the opposite role of apoC3 and apoA5 in lipid metabolism and CAD risk, and discussed the potential correlation between these two apolipoproteins.

Cuban Sugar Cane Wax Acid and Policosanol Showed Similar Atheroprotective Effects with Inhibition of LDL Oxidation and Cholesteryl Ester Transfer via Enhancement of High-Density Lipoproteins Functionality

Background

Cuban sugarcane wax acids (SCWA) and policosanol (PCO) are mixtures of higher aliphatic acids and alcohols, respectively, purified from sugarcane wax with different chief components. Although it has been known that they have antioxidant and anti-inflammatory activities, physiological properties on molecular mechanism of SCWA have been less studied than PCO.

Methods

In this study, we compared antiatherogenic activities of SCWA and PCO via encapsulation with reconstituted high-density lipoproteins (rHDL).

Results

After reconstitution, SCWA-rHDL showed smaller particle size than PCO-rHDL with increase of content. PCO-rHDL or SCWA-rHDL showed distinct inhibition of glycation with similar extent in the presence of fructose. PCO-rHDL or SCWA-rHDL showed strong antioxidant activity against cupric ion-mediated oxidation of low-density lipoproteins (LDL), and inhibition of oxLDL uptake into macrophages. Although PCO-rHDL showed 1.2-fold stronger inhibition against cholesteryl ester transfer protein (CETP) activity than SCWA-rHDL, SCWA-rHDL enhanced 15% more brain cell (BV-2) growth and 23% more regeneration of tail fin in zebrafish.

Conclusion

PCO and SCWA both enhance the beneficial functions of HDL to maximize its antioxidant, antiglycation, and antiatherosclerotic activities and the inhibition of CETP. These enhancements of HDL functionality by PCO and SCWA could exert antiaging and rejuvenation activity.

Consumption of Cuban Policosanol Improves Blood Pressure and Lipid Profile via Enhancement of HDL Functionality in Healthy Women Subjects: Randomized, Double-Blinded, and Placebo-Controlled Study

Policosanol has been reported to improve blood pressure, lipid profile, and HDL functionality via inhibition of cholesteryl ester transfer protein (CETP) both in vitro and in vivo in zebrafish and human models. However, there are limited reports and randomized, double-blinded trials on policosanol that could advocate the blood pressure-lowering effect in prehypertensive participants. Therefore, we performed in vitro, in vivo, and ex vivo experiments to provide more substantial and concrete data on the blood pressure-lowering effect of policosanol. Consumption of policosanol for 8 weeks enhanced plasma antioxidant activity. In the policosanol group, plasma total cholesterol (TC) and triglyceride (TG) levels were reduced up to 20% and 14%, respectively, and HDL-C level was elevated up to 1.3-fold compared to that at week 0. TG/HDL-C and cholesteryl ester transfer protein (CETP) activities were reduced up to 36% and 20%, respectively. Uptake of oxidized LDL in macrophages was reduced as oxidized species levels were reduced, and HDL₂-associated paraoxonase activities were enhanced by 60% compared to those at week 0. Encapsulation of policosanol into reconstituted HDL (PCO-rHDL) enhanced cholesterol efflux activity and insulin secretion capacity. In conclusion, consumption of policosanol for 8 weeks in healthy female subjects resulted in lowered blood pressure and CETP activity via elevation of HDL/apoA-I contents and enhancement of HDL functionalities, including cholesterol efflux and insulin secretion. These functional enhancements of HDL can contribute to the prevention of aging-related diseases, hypertension, and stroke.

The Ability of Different Ketohexoses to Alter Apo-A-I Structure and Function In Vitro and to Induce Hepatosteatosis, Oxidative Stress, and Impaired Plasma Lipid Profile in Hyperlipidemic Zebrafish

In the current study, we have tested the nonenzymatic glycation activities of ketohexoses, such as tagatose and psicose. Although tagatose-treated apoA-I (t-A-I) and psicose-treated apoA-I (p-A-I) exerted more inhibitory activity you cupric ion-mediated low-density lipoprotein (LDL) oxidation and oxidized LDL (oxLDL) phagocytosis into macrophage than fructose-treated apoA-I (f-A-I). In the lipid-free state, t-A-I and f-A-I showed more multimerized band without crosslinking. Since t-A-I lost its phospholipid binding ability, the rHDL formation was not as successful as f-A-I. However, injecting t-A-I showed more antioxidant activities in zebrafish embryo under the presence of oxLDL. Three weeks of consumption of fructose (50% of wt in Tetrabit/4% cholesterol) showed a 14% elevation of serum triacylglycerol (TG), while tagatose-administered group showed 30% reduction in serum TG compared to high cholesterol control. Fructose-fed group showed the biggest area of Oil Red O staining with the intensity as strong as the HCD control. However, tagatose-consumed group showed much lesser Oil Red O-stained area with the reduction of lipid accumulation. In conclusion, although tagatose treatment caused modification of apoA-I, the functional loss was not as much severe as the fructose treatment in macrophage cell model, zebrafish embryo, and hypercholesterolemic zebrafish model.

Blood Pressure Lowering Effect of Cuban Policosanol is Accompanied by Improvement of Hepatic Inflammation, Lipoprotein Profile, and HDL Quality in Spontaneously Hypertensive Rats

We investigated the antihypertensive effect of policosanol on spontaneously hypertensive rats (SHR). For this, we analyzed blood pressure, blood lipid, and lipoprotein properties in male SHR after consumption of Cuban policosanol (PCO). The experimental groups were as follows: normotensive Wistar Kyoto (WKY) control, SHR group fed normal diet (ND), SHR group fed 20 mg of PCO, SHR group fed 100 mg of PCO, and SHR group fed 200 mg of PCO per kg of body weight. After eight weeks, the SHR control group showed gradual increases up to 21% in systolic blood pressure (SBP) and diastolic blood pressure (DBP) compared with values at week 0. However, policosanol consumption had a dose-dependent reduction effect on SBP and also reduced DBP up to 17% in a dose-dependent manner. Heart rate (HR) bpm increased by six percent in the SHR control, whereas the 20 mg, 100 mg, and 200 mg of policosanol groups showed a reduction of 36%, 28%, and 34% respectively. Although serum total cholesterol (TC) level of SHR was not affected by policosanol consumption (70⁻80 mg/dL), serum triglyceride (TG) level significantly decreased in the SHR + 200 mg of PCO group. Serum high-density lipoprotein cholesterol (HDL-C) level was also significantly elevated by policosanol consumption. The % HDL-C/TC ratio was elevated in the policosanol group up to 67⁻70%, whereas the SHR control group showed a ratio of 58%. Serum cholesteryl ester transfer protein (CETP) activity was reduced by policosanol in a dose-dependent manner. Although the serum glutamate oxaloacetate transaminase (GOT)/ glutamate pyruvate transaminase (GPT) were similar across all groups, policosanol consumption caused reduction of reactive oxygen species (ROS) levels in hepatic tissue. The SHR control group showed a 2.1-fold higher serum C-reactive protein (CRP) level than the WKY group, whereas the CRP level decreased in the SHR + 200 mg of PCO group (up to 45%) than SHR control group. Aldosterone level was reduced in the policosanol group (up to 34%) in a dose-dependent manner compared to the control. In conclusion, eight weeks of policosanol consumption in SHR resulted in remarkable reduction of blood pressure, serum aldosterone, and serum TG levels along with the elevation of HDL-C and improvement of hepatic inflammation.

Slim Body Weight Is Highly Associated With Enhanced Lipoprotein Functionality, Higher HDL-C, and Large HDL Particle Size in Young Women

There has been no information about the correlations between body weight distribution and lipoprotein metabolism in terms of high-density lipoproteins-cholesterol (HDL-C) and cholesteryl ester transfer protein (CETP). In this study, we analyzed the quantity and quality of HDL correlations in young women (21.5 ± 1.2-years-old) with a slim (n = 21, 46.2 ± 3.8 kg) or plump (n = 30, 54.6 ± 4.4 kg) body weight. Body weight was inversely correlated with the percentage of HDL-C in total cholesterol (TC). The plump group showed 40% higher body fat (26 ± 3 %) and 86% more visceral fat mass (VFM, 1.3 ± 0.3 kg) than the slim group, which showed 18 ± 2% body fat and 0.7 ± 0.2 kg of VFM. Additionally, the plump group showed 20% higher TC, 58% higher triglyceride (TG), and 12% lower HDL-C levels in serum. The slim group showed 34% higher apoA-I but 15% lower CETP content in serum compared to the plump group. The slim group showed a 13% increase in particle size and 1.9-fold increase in particle number with enhanced cholesterol efflux activity. Although the plump group was within a normal body mass index (BMI) range, its lipid profile and lipoprotein properties were distinctly different from those of the slim group in terms of CETP mass and activity, HDL functionality, and HDL particle size.

Cord and maternal sera from small neonates share dysfunctional lipoproteins with proatherogenic properties: Evidence for Barker's hypothesis

BACKGROUND

Fetal growth restriction (GR) is associated with perinatal mortality and subsequent metabolic disorders in adulthood. Until now, there is little information regarding changes in the properties of lipoproteins from growth-restricted fetuses and their maternal sera.

OBJECTIVE

To identify unique lipoprotein biomarkers for fetal GR in maternal and cord sera from small neonates, we analyzed lipoprotein compositions and functions.

METHODS

Lipoprotein compositions and functions were compared between cord blood and maternal blood among small for gestational age neonates (SGA; n = 15, 2589 ± 50 g) and appropriate for gestational age neonates (AGA; n = 15) in Korea.

RESULTS

Cord blood from the SGA group showed 2-fold higher triglyceride (TG) and TG/high-density lipoprotein cholesterol levels than the AGA group as well as significantly lower (up to 20%) paraoxonase activity and apolipoprotein (apo) A-I content. The SGA group showed the highest cholesteryl ester transfer protein activities in both cord and maternal sera. SGA neonates showed elevated apo-B content in very low-density lipoprotein, 52% reduction of apo A-I content in high-density lipoprotein, and 30% increased glycation (P < .001) compared with AGA neonates. Especially, low-density lipoprotein from the SGA group showed 1.9-fold higher sensitivity to oxidation as well as 3-fold greater uptake into macrophages, suggesting stronger proatherosclerotic properties. Lipoproteins from maternal serum of SGA neonates showed greater oxidation along with TG enrichment and loss of antioxidant ability. On microinjection of cord serum (50 nL) into zebrafish embryos, the SGA group showed the most severe embryonic damage.

CONCLUSIONS

Lipoproteins from cord and maternal sera of SGA neonates resulted in severe impairment of functional and structural correlations accompanied by greater pro-oxidant and proatherosclerotic properties.

Consumption of policosanol enhances HDL functionality via CETP inhibition and reduces blood pressure and visceral fat in young and middle-aged subjects

It is well-known that policosanol can improve serum lipid profiles, although the physiological mechanism is still unknown. Here, we investigated functional and structural changes in lipoproteins after consumption of policosanol. To investigate the physiological effect of policosanol, we analyzed serum parameters in young non-smoker (YN; n=7, 24.0±2.4 years), young smoker (YS; n=7, 26.3±1.5 years), and middle-aged subjects (MN; n=11, 52.5±9.8 years) who consumed policosanol daily (10 mg/day) for 8 weeks. After 8 weeks, systolic blood pressure was significantly lowered to 4% (7 mmHg, p=0.022) from initial levels in the YS and MN groups. Moisture content of facial skin increased up to 38 and 18% from initial levels in the YS and MN groups, respectively. Serum triglyceride (TG) levels decreased to 28 and 26% from initial levels in the YN and MN groups, respectively. The percentage of high-density lipoprotein-cholesterol (HDL-C) in total cholesterol was elevated in all subjects (YN, 36%; YS, 35%; MN, 8%) after 8 weeks of policosanol consumption. All groups showed a reduction in serum glucose and uric acid levels. Serum cholesteryl ester transfer protein (CETP) activity was significantly diminished up to 21 and 32% from initial levels in the YN and MN groups, respectively. After 8 weeks, oxidation of the low-density lipoprotein fraction was markedly reduced accompanied by decreased apolipoprotein B (apoB) fragmentation. In the HDL fraction, paraoxonase activity was elevated by 17% along with elevation of apoA-I and cholesterol contents. Electron microscopy revealed that the size and number of HDL particles increased after 8 weeks, and the YS group showed a 2-fold increase in particle size. Daily consumption of policosanol for 8 weeks resulted in lowered blood pressure, reduced serum TG level and CETP activity, and elevated HDL-C contents. These functional enhancements of HDL can prevent and/or attenuate aging-related diseases, hypertension, diabetes and coronary heart disease.

Altered lipoproteins in patients with systemic lupus erythematosus are associated with augmented oxidative stress: a potential role in atherosclerosis

Background

To examine the structural and oxidative properties of lipoproteins from patients with systemic lupus erythematosus (SLE).

Methods

The lipid profiles of 35 SLE patients and 15 healthy controls (HCs) were compared. Oxidation status, susceptibility to oxidation, and structural integrity of low-density lipoprotein (LDL) were determined by measuring malondialdehyde (MDA), de novo formation of conjugated dienes in the presence of CuSO₄, and mobility on gel electrophoresis, respectively. In vitro foam cell formation and the oxidative potential in zebrafish embryos were examined.

Results

LDL levels in SLE patients and HCs were similar (p = 0.277). LDL from SLE patients was more fragmented than that from HCs. In addition, LDL from SLE patients was more oxidized than LDL from HCs (p < 0.001) and more susceptible to de novo oxidation (p < 0.001) in vitro. THP-1 cells engulfed more LDL from SLE patients than LDL from HCs (p < 0.001). LDL from SLE patients, which was injected into zebrafish embryos, induced a higher degree of oxidation and a higher mortality than LDL from HCs (both p < 0.001). The survival of embryos treated with oxidized LDL was significantly better in the presence of HDL₃ from HCs than that from SLE patients (all p < 0.001).

Conclusions

Lipoproteins from SLE patients exhibited greater oxidative potential, which might contribute to accelerated atherosclerosis in SLE.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1204-x) contains supplementary material, which is available to authorized users.

Patients with Rheumatoid Arthritis Show Altered Lipoprotein Profiles with Dysfunctional High-Density Lipoproteins that Can Exacerbate Inflammatory and Atherogenic Process

Objective

In order to identify putative biomarkers in lipoprotein, we compared lipid and lipoprotein properties between rheumatoid arthritis (RA) patients and control with similar age.

Methods

We analyzed four classes of lipoproteins (VLDL, LDL, HDL₂, HDL₃) from both male (n = 8, 69±4 year-old) and female (n = 25, 53±7 year-old) rheumatoid arthritis (RA) patients as well as controls with similar age (n = 13).

Results

Although RA group showed normal levels of total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, and glucose, however, the RA group showed significantly reduced high-density lipoprotein (HDL)-C level and ratio of HDL-C/TC. The RA group showed significantly elevated levels of blood triglyceride (TG), uric acid, and cholesteryl ester transfer protein (CETP) activity. The RA group also showed elevated levels of advanced glycated end (AGE) products in all lipoproteins and severe aggregation of apoA-I in HDL. As CETP activity and TG contents were 2-fold increased in HDL from RA group, paraoxonase activity was reduced upto 20%. Electron microscopy revealed that RA group showed much less HDL₂ particle number than control. LDL from the RA group was severely oxidized and glycated with greater fragmentation of apo-B, especially in female group, it was more atherogenic via phagocytosis.

Conclusion

Lipoproteins from the RA patients showed severely altered structure with impaired functionality, which is very similar to that observed in coronary heart patients. These dysfunctional properties in lipoproteins from the RA patients might be associated with high incidence of cardiovascular events in RA patients.

Apolipoprotein C-III Nanodiscs Studied by Site-Specific Tryptophan Fluorescence

Apolipoprotein C-III (ApoC-III) is found on high-density lipoproteins (HDLs) and remodels 1,2-dimyristoyl-sn-glycero-3-phosphocholine vesicles into HDL-like particles known as nanodiscs. Using single-Trp-containing ApoC-III mutants, we have studied local side chain environments and interactions in nanodiscs at positions W42, W54, and W65. Using transmission electron microscopy and circular dichroism spectroscopy, nanodiscs were characterized at the ultrastructural and secondary conformational levels, respectively. Nearly identical particles (15 ± 2 nm) were produced from all proteins containing approximately 25 ± 4 proteins per particle with an average helicity of 45-51% per protein. Distinct residue-specific fluorescence properties were observed with W54 residing in the most hydrophobic environment followed by W42 and W65. Interestingly, time-resolved anisotropy measurements revealed that Trp side chain mobility is uncorrelated to the polarity of its surroundings. W54 is the most mobile compared to W65 and W42, which are more immobile in a nanodisc-bound state. On the basis of Trp spectral comparisons of ApoC-III in micellar and vesicle environments, ApoC-III binding within nanodiscs more closely resembles a bilayer-bound state. Despite the nanodiscs being structurally similar, we found marked differences during nanodisc formation by the Trp variants as a function of temperature, with W42 behaving the most like the wild-type protein. Our data suggest that despite the modest mutations of Trp to Phe at two of the three native sites, the interfacial location of W42 is important for lipid binding and nanodisc assembly, which may be biologically meaningful as of the three Trp residues, only W42 is invariant among mammals.

Development of Antisense Drugs for Dyslipidemia

Abnormal elevation of low-density lipoprotein (LDL) and triglyceride-rich lipoproteins in plasma as well as dysfunction of anti-atherogenic high-density lipoprotein (HDL) have both been recognized as essential components of the pathogenesis of atherosclerosis and are classified as dyslipidemia. This review describes the arc of development of antisense oligonucleotides for the treatment of dyslipidemia. Chemically-armed antisense candidates can act on various kinds of transcripts, including mRNA and miRNA, via several different endogenous antisense mechanisms, and have exhibited potent systemic anti-dyslipidemic effects. Here, we present specific cutting-edge technologies have recently been brought into antisense strategies, and describe how they have improved the potency of antisense drugs in regard to pharmacokinetics and pharmacodynamics. In addition, we discuss perspectives for the use of armed antisense oligonucleotides as new clinical options for dyslipidemia, in the light of outcomes of recent clinical trials and safety concerns indicated by several clinical and preclinical studies.

Anti-Aging and Tissue Regeneration Ability of Policosanol Along with Lipid-Lowering Effect in Hyperlipidemic Zebrafish via Enhancement of High-Density Lipoprotein Functionality

We investigated the tissue regeneration and lipid-lowering effects of policosanol (PCO) by employing a hyperlipidemic zebrafish model. A reconstituted high-density lipoprotein containing policosanol (PCO-rHDL) facilitated greater cell growth and replication with less apoptosis and reactive oxygen species (ROS) production in BV-2 microglial cell lines. From in vivo study, injection of rHDL containing apolipoprotein A-I (ApoA-I) caused 76 ± 4% (p = 0.01) greater tissue regeneration activity than the phosphate-buffered saline (PBS) control, whereas PCO-rHDL caused 94 ± 7% (p = 0.002) increased regeneration. PCO in ethanol (EtOH) showed lower cholesteryl ester transfer protein (CETP) inhibitory ability than did anacetrapib, whereas PCO-rHDL showed higher inhibitory ability than anacetrapib, suggesting a synergistic effect between PCO and rHDL. Following 9 weeks of PCO consumption, the PCO group (0.003% PCO in Tetrabit) showed the highest survivability (80%), whereas normal diet (ND) and high-cholesterol diet (HCD) control groups showed 67% and 70% survival rates, respectively. Supplementation with a HCD resulted in two-fold elevation of CETP activity along with 3- and 2.5-fold increases in serum total cholesterol (TC) and triglycerides (TGs) levels, respectively. Consumption of PCO for 9 weeks resulted in 40 ± 5% (p = 0.01 vs. HCD) and 33 ± 4% (p = 0.02 vs. HCD) reduction of TC and TGs levels, respectively. Serum high-density lipoprotein cholesterol (HDL-C) level increased up to 37 ± 2 mg/dL (p = 0.004), whereas the percentage of HDL-C/TC increased up to 20 ± 2% from 5 ± 1% compared to the HCD control. The serum glucose level was reduced to 47 ± 2% (p = 0.002) compared to the HCD control. Fatty liver change and hepatic inflammation levels were remarkably increased upon HCD consumption and were two-fold higher than that under ND. However, the PCO group showed 58 ± 5% (p = 0.001) and 50 ± 3% (p = 0.006) reduction of inflammation enzyme levels and lipid content in hepatic tissue under HCD. In conclusion, PCO supplementation showed lipid-lowering and HDL-C-elevating effects with ameliorating fatty liver change. These in vivo anti-atherosclerotic and anti-diabetic effects of PCO are well associated with in vitro anti-apoptotic activities.

Incorporation of human growth hormone-2 into proteoliposome enhances tissue regeneration with anti-oxidant and anti-senescence activities

Human growth hormone-2 (GH-2) is a 191-amino-acid protein also known as human placental hormone. During pregnancy, continuous secretion of GH-2 appears to have important implications for physiological adjustment to gestation, especially in controlling levels of maternal insulin-like growth factor 1. To compare the physiological activity of GH-2 between lipid-free and lipid-bound states, GH-2 was expressed and incorporated into proteoliposome. GH-2 was expressed and purified using a pET28(a)-GH-2 vector in an Escherichia coli system. Purified GH-2 was then characterized and synthesized into reconstituted high-density lipoprotein (rHDL). The expression yield of GH-2 was 20-30 mg by BL21 (DE3) cells in 1 liter of Luria-Bertani broth. Purified GH-2 of at least 98% purity (23 kDa) was incorporated into rHDL with human apolipoprotein A-I (ApoA-I) and palmitoyloleoyl phosphatidylcholine (POPC) at a 1:1:95 (GH-2:ApoA-I:POPC) molar ratio. Structural analysis revealed that GH-2 had a 44% α-helix content and a wavelength maximum fluorescence (WMF) of 349 nm in a lipid-free state. In a lipid-bound state, the WMF of GH-2 was ∼4 nm blue-shifted (345 nm), with 50% of α-helix content. The lipid-bound GH-2 showed enhanced anti-atherosclerotic activity and anti-senescence activity with inhibition of fructose-mediated glycation. A fin regeneration experiment using zebrafish (17 weeks old, n=9) showed that lipid-bound GH-2 enhanced regeneration efficiency by 44% compared to native GH-2 (in the lipid-free state) without any notable side effects. GH-2 has anti-oxidant activity to enhance tissue regeneration as well as to exert anti-diabetic activity. Incorporation of GH-2 into rHDL can enhance structural stability and tissue regeneration efficiency in vertebrate models, indicating a synergetic effect between GH-2 and ApoA-I in rHDL.

Evolving targets for lipid-modifying therapy

The pathogenesis and progression of atherosclerosis are integrally connected to the concentration and function of lipoproteins in various classes. This review examines existing and emerging approaches to modify low-density lipoprotein and lipoprotein (a), triglyceride-rich lipoproteins, and high-density lipoproteins, emphasizing approaches that have progressed to clinical evaluation. Targeting of nuclear receptors and phospholipases is also discussed.

Reconstituted High-Density Lipoprotein Containing Human Growth Hormone-1 Shows Potent Tissue Regeneration Activity with Enhancement of Anti-Oxidant and Anti-Atherosclerotic Activities

BACKGROUND

Human growth hormone-1 (GH-1), somatotropin, is a peptide hormone that stimulates cell division in tissues such as bone and cartilage.

METHODS

To compare physiological activities in lipid-free and lipid-bound states, we expressed and incorporated GH-1 in reconstituted high-density lipoprotein (rHDL).

RESULTS

GH-1 was expressed and purified using the pET30(a) vector and an Escherichia coli expression system. Purified GH-1 (at least 98% purity, 23 kD) was characterized and synthesized with apolipoproteinA-I (apoA-I), 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC), and cholesterol. Secondary structure analysis of GH-1 revealed 54% α-helical content in a lipid-free state and 65% α-helical content in a lipid-bound state along with blue-shifted tryptophan movement (around 2 nm). GH-1 caused less uptake of oxidized low-density lipoprotein (oxLDL) into macrophages and inhibited senescence of dermal cells in a dose-dependent manner. GH-1 in a lipid-bound state exerted stronger inhibitory activity than in a lipid-free state, indicating improved anti-atherosclerotic activity due to the lipid formulation. In a fin regeneration experiment using zebrafish (17 weeks old, n=9), GH-1 showed its highest regeneration speed without any side effects. GH-1-rHDL containing apoA-I showed 2.3-fold and 1.6-fold higher regeneration speeds than lipid-free GH-1 (in native state) and lipid-bound GH-1, respectively.

CONCLUSION

Incorporation of GH-1 and apoA-I in HDL enhanced tissue regeneration activity of amputated tail fin, indicating a synergetic effect between GH-1 and apoA-I in a lipid-bound state.

Association between lipids, lipoproteins composition of HDL particles and triglyceride-rich lipoproteins, and LCAT and CETP activity in post-renal transplant patients

High-density lipoprotein (HDL) remodeling within the plasma compartment and the association between lecithin-cholesterol acyltransferase (LCAT) and cholesterol ester transfer protein (CETP) activity, and lipid, lipoprotein concentrations and composition were investigated. The aim was to examine the high sensitivity of C-reactive protein (hsCRP), lipid, apolipoprotein B (apoB), apoAI, total apoAII, apoAIInonB, apoB-containing apoAII (apoB:AII), total apoCIII, apoCIIInonB, apoB-containing apoCIII (apoB:CIII) concentration and LCAT and CETP activity to gain an insight into the association between them and LCAT and CETP, 57 post-renal transplant (Tx) patients with and without statin therapy and in 15 healthy subjects. Tx patients had moderate hypertriglyceridemia, hypercholesterolemia, and dyslipoproteinemia, disturbed triglyceride-rich lipoproteins (TRLs) and HDL composition, decreased LCAT, and slightly increased hsCRP but no CETP activity. Spearman’s correlation test showed the association between lipids and lipoproteins and LCAT or CETP, and multiple ridge stepwise forward regression showed that immunosuppressive therapy in Tx patients can disturb HDL and TRLs composition. The results suggest that inhibition or activation of LCAT is due, in part, to HDL-associated lipoprotein. Lipoprotein composition of apoAI, apoAIInonB, and apoCIIInonB in HDL particle and apoB:AII TRLs can contribute to decrease LCAT mass in Tx patients. Tx patients without statin and with lower triglycerides but higher HDL cholesterol concentration and disturbed lipoprotein composition of ApoAI and apoAII in HDL particle can decrease LCAT, increase LDL cholesterol, aggravate renal graft, and accelerate atherosclerosis and chronic heart diseases.

Bovine apolipoprotein (apo)A-I displays more enhanced antioxidant and anti-atherosclerotic activity in lipid-free and lipid-bound states than human and porcine apoA-I

Apolipoprotein A-I (apoA-I) is a major component of high-density lipoprotein (HDL), which displays anti-atherosclerotic activity in plasma. In the current study, we compared the functional and structural characteristics of human, bovine and porcine apoA-I as regards their antioxidant ability and protein stability. In the lipid-free state, the immunoreactivity of bovine and porcine apoA-I differed from that of human apoA-I and bovine and porcine apoA-I exhibited greater resistance to denaturation induced by urea treatment. Bovine apoA-I showed the weakest binding ability of dimyristoyl phosphatidylcholine; however, bovine apoA-I formed slightly larger reconstituted HDL (rHDL) particles with palmitoyl oleoyl phosphatidylcholine, with a higher number of apoA-I-containing particles. Bovine and porcine apoA-I comprised of pentameric structures, whereas human apoA-I in the rHDL state consisted of trimeric structures. Although apoA-I from all three species showed a similar content of α-helicity in the lipid-free state (approximately 53%), bovine apoA-I showed a lower α-helicity content (approximately 66%) compared with human apoA-I (approximately 74%) in the rHDL state. Bovine apoA-I was more resistant to denaturation and glycation upon treatment with urea and fructose, respectively. Furthermore, bovine apoA-I showed a greater inhibition of cupric ion-mediated low-density lipoprotein (LDL) oxidation and uptake of acetylated LDL by macrophages compared with human or porcine apoA-I in the lipid-free and lipid-bound states. In conclusion, bovine apoA-I has unique functional properties in the lipid-free and lipid-bound states, and displays significantly enhanced anti-atherosclerotic activity.

A proteoliposome containing apolipoprotein A-I mutant (V156K) enhances rapid tumor regression activity of human origin oncolytic adenovirus in tumor-bearing zebrafish and mice

We recently reported that the efficiency of adenoviral gene delivery and virus stability are significantly enhanced when a proteoliposome (PL) containing apolipoprotein (apo) A-I is used in an animal model. In the current study, we tested tumor removal activity of oncolytic adenovirus (Ad) using PL-containing wildtype (WT) or V156K. Oncolytic Ad with or without PL was injected into tumors of zebrafish and nude mice as a Hep3B tumor xenograft model. The V156K-PL-Ad-injected zebrafish, group showed the lowest tumor tissue volume and nucleic acids in the tumor area, whereas injection of Ad alone did not result in adequate removal of tumor activity. Reactive oxygen species (ROS) contents increased two-fold in tumor-bearing zebrafish; however, the V156K-PL-Ad injected group showed a 40% decrease in ROS levels compared to that in normal zebrafish. After reducing the tumor volume with the V156K-PL-Ad injection, the swimming pattern of the zebrafish changed to be more active and energetic. The oncolytic effect of PL-Ad containing either V156K or WT was about two-fold more enhanced in mice than that of Ad alone 34 days after the injection. Immunohistochemical analysis revealed that the PL-Ad-injected groups showed enhanced efficiency of viral delivery with elevated Ad-E1A staining and a diminished number of proliferating tumor cells. Thus, the antitumor effect of oncolytic Ad was strongly enhanced by a PL-containing apoA-I and its mutant (V156K) without causing side effects in mice and zebrafish models.

Grape skin and loquat leaf extracts and acai puree have potent anti-atherosclerotic and anti-diabetic activity in vitro and in vivo in hypercholesterolemic zebrafish

Three major sources of flavonoids and phenolic compounds, which are commonly used in food industry, namely loquat leaf (LL), grape skin (GS) and acai puree, were tested in regard to their potential anti-atherosclerotic and anti-diabetic activity. The compounds were evaluated by in vitro antioxidant assay using a macrophage model and for in vivo hypolipidemic activity using zebrafish. In assays in vitro, all extracts demonstrated potent ferric ion reductive capacity, radical-scavenging activity and inhibition of low-density lipoprotein (LDL) oxidation at a final concentration of 0.1 mg/ml. Extracts could also abrogate fructose-mediated protein glycation and mildly inhibit cholesteryl ester transfer protein (CETP). Cellular uptake of oxidized or acetylated LDL into macrophages was inhibited by acai treatment (final concentration, 0.1 mg/ml) and moderately diminished by GS and LL extracts. After 4 weeks of feeding on a high cholesterol diet (HCD), zebrafish exhibited serum total cholesterol (TC) and triglyceride (TG) levels 2.5-fold higher than those fed a normal diet (ND). Within the experimental group, those fed acai demonstrated the lowest serum TC and CETP activity, while the LL-consuming group showed a reduction in serum TC and TG relative to HCD-fed fish. Serum glucose levels also increased in the HCD group, to threefold above the ND group; GS and LL feeding elicited the greatest reduction in hyperglycemia. The groups consuming acai and LL showed much less hepatic inflammation, as well as attenuation of fatty liver and a reduced content of oxidized species. In conclusion, extracts of LL, GS, and acai shared antioxidant, anti-inflammatory and anti-atherosclerotic activity in cellular assays and in a hypercholesterolemic zebrafish model.

Females with angina pectoris have altered lipoprotein metabolism with elevated cholesteryl ester transfer protein activity and impaired high-density lipoproteins-associated antioxidant enzymes

In order to investigate non-invasive biomarkers for angina pectoris (AP), we analyzed the lipid and protein composition in individual lipoproteins from females with angina pectoris (n=22) and age- and gender-matched controls (n=20). In the low-density lipoprotein (LDL) fraction, the triglycerides (TG) and protein content increased in the AP group compared to the control group. The AP group had lower total cholesterol (TC) and elevated TG in the high-density lipoprotein (HDL) fraction. In the AP group, cholesteryl ester transfer protein (CETP) activity was enhanced in HDL and LDL, while lecithin:cholesterol acyltransferase (LCAT) activity in HDL₃ was almost depleted. Antioxidant activity was significantly decreased in the HDL₃ fraction, with a decrease in the HDL₂ particle size. In the HDL₃ fraction, paraoxonase and platelet activating factor-acetylhydrolase (PAF-AH) activity were much lower and the levels of CETP and apoC-III were elevated in the AP group. The LDL from the AP group was more sensitive to cupric ion-mediated oxidation with faster mobility. In conclusion, the lipoprotein fractions in the AP group had impaired antioxidant activity and increased TG and apoC-III with structural and functional changes.

A zebrafish model for the rapid evaluation of pro-oxidative and inflammatory death by lipopolysaccharide, oxidized low-density lipoproteins, and glycated high-density lipoproteins

Oxidation and inflammation are leading causes of nearly all chronic metabolic disorders, and play major roles in cardiovascular disease, cancer, and chronic age-dependent disease. High-density lipoprotein (HDL) and apolipoprotein (apo) A-I have strong antioxidant and anti-inflammatory properties in the plasma. Fructose-induced non-enzymatic glycation of apoA-I can lead to the production of dysfunctional apoA-I and HDL. To compare the physiologic effects of dysfunctional apoA-I and HDL, reconstituted HDL containing native apoA-I (nA-I) or glycated apoA-I (gA-I) was injected into zebrafish embryos in the presence of inflammatory molecules. Co-injection of reconstituted HDL containing VLDL and LDL gA-I (gA-I-rHDL) and lipopolysaccaride (LPS) resulted in acute embryo deaths, while rHDL containing nA-I (nA-I-rHDL) and LPS resulted in significantly enhanced survival. Co-injection of oxidized LDL (oxLDL) and nA-I-rHDL improved embryo survival, while co-injection of oxLDL and gA-I-rHDL aggravated inflammatory deaths. Furthermore, co-injection of oxLDL and HDL(2) (5 ng of protein) or HDL(3) (15 ng of protein) from the young group (22 ± 2 years old) showed significantly increased embryo survival compared with the same co-injection of HDL from the elderly group (71 ± 4 years old). In conclusion, our assay system provides a rapid and economic method to screen antioxidant and anti-inflammatory agents using zebrafish embryos.

Turmeric and laurel aqueous extracts exhibit in vitro anti-atherosclerotic activity and in vivo hypolipidemic effects in a zebrafish model

Culinary herbs and spices have been widely used for their hypoglycemic, lipid-lowering, and anti-inflammatory activities. This study examined the physiologic activity of hydrophilic components using extracts of turmeric or laurel leaf powder. Aqueous extracts of turmeric and laurel showed potent inhibitory activity against fructose-mediated glycation with antioxidant ability against low-density lipoprotein (LDL) oxidation and radical scavenging activity. The turmeric and laurel extracts had potent cholesteryl ester transfer protein (CETP) inhibitory ability (up to 23% and 40% inhibition, respectively) at a final concentration of 10 μg/mL. The turmeric and laurel extracts inhibited the cellular uptake of oxidized LDL into macrophages, which is the initial step in atherogenesis. For in vivo testing, zebrafish consumed a high cholesterol diet (HCD) (final concentration, 4% [wt/wt]) with or without turmeric or laurel powder (final concentration, 10% [wt/wt]). The turmeric and laurel groups had a 14% and 12% decrease, respectively, in the weight and height ratios compared to the HCD group. The plasma total cholesterol level was significantly lower in the turmeric and laurel groups (48% and 28% less, respectively, than in the HCD group). Plasma triglycerides were more markedly reduced in the turmeric and laurel groups than in the HCD group (68% and 56% less, respectively, than the HCD group). In conclusion, the hydrophilic extracts of turmeric and laurel potently suppressed the incidence of atherosclerosis via a strong antioxidant potential, prevention of apolipoprotein A-I glycation and LDL phagocytosis, and inhibition of CETP. Consumption of turmeric and laurel extracts exhibited hypolipidemic and antioxidant activities in a hypercholesterolemic zebrafish model.

Aspartame-fed zebrafish exhibit acute deaths with swimming defects and saccharin-fed zebrafish have elevation of cholesteryl ester transfer protein activity in hypercholesterolemia

Although many artificial sweeteners (AS) have safety issues, the AS have been widely used in industry. To determine the physiologic effect of AS in the presence of hyperlipidemia, zebrafish were fed aspartame or saccharin with a high-cholesterol diet (HCD). After 12 days, 30% of zebrafish, which consumed aspartame and HCD, died with exhibiting swimming defects. The aspartame group had 65% survivability, while the control and saccharin groups had 100% survivability. Under HCD, the saccharin-fed groups had the highest increase in the serum cholesterol level (599 mg/dL). Aspartame-fed group showed a remarkable increase in serum glucose (up to 125 mg/dL), which was 58% greater than the increase in the HCD alone group. The saccharin and HCD groups had the highest cholesteryl ester transfer protein (CETP) activity (52% CE-transfer), while the HCD alone group had 42% CE-transfer. Histologic analysis revealed that the aspartame and HCD groups showed more infiltration of inflammatory cells in the brain and liver sections. Conclusively, under presence of hyperlipidemia, aspartame-fed zebrafish exhibited acute swimming defects with an increase in brain inflammation. Saccharin-fed zebrafish had an increased atherogenic serum lipid profile with elevation of CETP activity.

Water extracts of cinnamon and clove exhibits potent inhibition of protein glycation and anti-atherosclerotic activity in vitro and in vivo hypolipidemic activity in zebrafish

Advanced glycation end products contribute to the pathogenesis of diabetic complications and atherosclerosis. Aqueous extracts of ground pepper, cinnamon, rosemary, ginger, and clove were analyzed and tested for anti-atherosclerotic activity in vitro and in vivo using hypercholesterolemic zebrafish. Cinnamon and clove extracts (at final 10 μg/mL) had the strongest anti-glycation and antioxidant activity in this study. Cinnamon and clove had the strongest inhibition of activity against copper-mediated low-density lipoprotein (LDL) oxidation and LDL phagocytosis by macrophages. Cinnamon or clove extracts had potent cholesteryl ester transfer protein (CETP) inhibitory activity in a concentration-dependent manner. They exhibited hypolipidemic activity in a hypercholesterolemic zebrafish model; the clove extract-treated group had a 68% and 80% decrease in serum cholesterol and TG levels, respectively. The clove extract-fed group had the smallest increase in body weight and height and the strongest antioxidant activity following a 5-week high cholesterol diet. Hydrophilic ingredients of cinnamon and clove showed potent activities to suppress the incidence of atherosclerosis and diabetes via strong antioxidant potential, prevention of apoA-I glycation and LDL-phagocytosis, inhibition of CETP, and hypolipidemic activity. These results suggest the potential to develop a new functional dietary agent to treat chronic metabolic diseases, such as hyperlipidemia and diabetes.

Modified apolipoprotein (apo) A-I by artificial sweetener causes severe premature cellular senescence and atherosclerosis with impairment of functional and structural properties of apoA-I in lipid-free and lipid-bound state

Long-term consumption of artificial sweeteners (AS) has been the recent focus of safety concerns. However, the potential risk of the AS in cardiovascular disease and lipoprotein metabolism has not been investigated sufficiently. We compared the influence of AS (aspartame, acesulfame K, and saccharin) and fructose in terms of functional and structural correlations of apolipoprotein (apo) A-I and high-density lipoproteins (HDL), which have atheroprotective effects. Long-term treatment of apoA-I with the sweetener at physiological concentration (3 mM for 168 h) resulted in loss of antioxidant and phospholipid binding activities with modification of secondary structure. The AS treated apoA-I exhibited proteolytic cleavage to produce 26 kDa-fragment. They showed pro-atherogenic properties in acetylated LDL phagocytosis of macrophages. Each sweetener alone or sweetener-treated apoA-I caused accelerated senescence in human dermal fibroblasts. These results suggest that long-term consumption of AS might accelerate atherosclerosis and senescence via impairment of function and structure of apoA-I and HDL.

High-density lipoprotein (HDL) from elderly and reconstituted HDL containing glycated apolipoproteins A-I share proatherosclerotic and prosenescent properties with increased cholesterol influx

High-density lipoprotein (HDL) is a strong antioxidant, anti-inflammatory, and antisenescence molecule. However, in the current study, HDL from the elderly group (E-HDL) exhibited increased glycation with apolipoprotein (apo) A-I multimerization and decreased phospholipid content. Similarly, glycated apoA-I (gA-I) by fructosylation has a covalently multimerized band without a crosslinker and impaired phospholipid-binding ability. Treatment of human dermal fibroblasts and macrophages with E-HDL and gA-I caused more severe cellular senescence and foam cell formation, respectively; however, treatment with HDL from a young group (Y-HDL) and native apoA-I (nA-I) suppressed senescence and atherosclerosis. E-HDL(3) and reconstituted HDL (rHDL) containing gA-I showed enhanced cholesterol influx into macrophages compared with Y-HDL(3) and nA-I-rHDL. In conclusion, E-HDL and gA-I-rHDL share similar physiologic properties in macrophages and human dermal fibroblasts. E-HDL and gA-I-rHDL exacerbated cellular senescence and atherosclerosis with increased cellular cholesterol influx.

Severely modified lipoprotein properties without a change in cholesteryl ester transfer protein activity in patients with acute renal failure secondary to Hantaan virus infection

Patients with hemorrhagic fever with renal syndrome (HFRS) often exhibit altered serum lipid and lipoprotein profile during the oliguric phase of the disease. Serum lipid and lipoprotein profiles were assessed during the oliguric and recovery phases in six male patients with HFRS. In the oliguric phase of HFRS, the apolipoprotein (apo) C-III content in high-density lipoproteins (HDL) was elevated, whereas the apoA-I content was lowered. The level of expression and activity of antioxidant enzymes were severely reduced during the oliguric phase, while the cholesteryl ester transfer protein activity and protein level were unchanged between the phases. In the oliguric phase, electromobility of HDL2 and HDL3 was faster than in the recovery phase. Low-density lipoprotein (LDL) particle size was smaller and the distribution was less homogeneous. Patients with HFRS in the oliguric phase had severely modified lipoproteins in composition and metabolism.

Effect in vitro of apolipoprotein A-V on the structure and functions of recombinant high density lipoprotein

The neighboring position of apolipoprotein A-I (apoA-I) and apolipoprotein A-V (apoA-V) gene and the modulation of apoA-V on the concentrations, size and maturation of high density lipoprotein (HDL) may indicate a special relationship between apoA-V and HDL. To assess the effects of apoA-V on HDL structure and related functions in vitro, a series of recombinant HDL (rHDL) were synthesized in vitro with various mass ratios of recombinant apoA-I: apoA-V. An increase in apoA-V in rHDL resulted in enhanced lipid-binding ability, increased phospholipid content and larger particle size. Furthermore, the lipid-free and lipid-bound apoA-V in rHDL showed antioxidant capacity against low density lipoprotein (LDL) in vitro. In THP-1 derived macrophages, apoA-V of rHDL was shown to have no influence on the uptake of oxidized LDL (oxLDL) and intracellular lipid accumulation. Thus, the addition of apoA-V to rHDL resulted in changes in several rHDL properties, including increased lipid-binding ability, phospholipid content, particle size and antioxidant capacity. These alterations may explain the modulation of apoA-V on HDL in vivo and the beneficial functions of apoA-V on atherosclerosis.

Inhibition of collar-induced carotid atherosclerosis by recombinant apoA-I cysteine mutants in apoE-deficient mice

The previous studies in our laboratory revealed that seven cysteine mutants of apolipoprotein A-I (apoA-I) have different structural features and biological activities in vitro and in vivo. To investigate the potential cardioprotective effects of apolipoprotein A-I(N74C) [apoA-I(N74C)], we examined the anti-inflammatory, antioxidant, and antiatherosclerotic effects of this cysteine mutant in a rapid atherosclerosis model induced by perivascular carotid collar placement in apoE⁻/⁻ mice. Lipid-free apoA-I(N74C) showed a significant increased antioxidant potency in low density lipoprotein (LDL) oxidation in vitro and reduced intracellular lipid accumulation in THP-1-derived macrophages, relative to wild-type apoA-I (apoA-Iwt). Mice injected with recombinant HDL (rHDL) reconstituted with apoA-I(N74C) (named rHDL74) through tail veins (40 mg/kg of body weight, three injections) had a significant lower level of serum interleukin-6 (IL-6) and enhanced serum antioxidation compared with mice receiving rHDL reconstituted with apoA-Iwt (named rHDLwt). Moreover, compared with rHDLwt, the rHDL74 in vivo injection resulted in a significant decrease in plaque size, ratio of aorta intima to media, arterial remodeling, and macrophage content in lesions. In summary, intravenous injection with rHDL74 reconstituted with apoA-I cysteine mutant apoA-I (N74C) dramatically delays the development of atherosclerosis induced by perivascular carotid collar placement and reduces vascular remodeling in the carotid artery in apoE⁻/⁻ mice.