High-density lipoprotein and atherosclerosis: Roles of lipid transporters

Various previous studies have found a negative cor-relation between the risk of cardiovascular events and serum high-density lipoprotein(HDL) cholesterol levels. The reverse cholesterol transport, a pathway of choles-terol from peripheral tissue to liver which has several potent antiatherogenic properties. For instance, the particles of HDL mediate to transport cholesterol from cells in arterial tissues, particularly from atherosclerotic plaques, to the liver. Both ATP-binding cassette trans-porters(ABC) A1 and ABCG1 are membrane cholesterol transporters and have been implicated in mediating cholesterol effluxes from cells in the presence of HDL and apolipoprotein A-I, a major protein constituent of HDL. Previous studies demonstrated that ABCA1 and ABCG1 or the interaction between ABCA1 and ABCG1 exerted antiatherosclerotic effects. As a therapeutic approach for increasing HDL cholesterol levels, much focus has been placed on increasing HDL cholesterol levels as well as enhancing HDL biochemical functions. HDL therapies that use injections of reconstituted HDL, apoA-I mimetics, or full-length apoA-I have shown dramatic effectiveness. In particular, a novel apoA-I mi-metic peptide, Fukuoka University ApoA-I Mimetic Pep-tide, effectively removes cholesterol via specific ABCA1 and other transporters, such as ABCG1, and has an an-tiatherosclerotic effect by enhancing the biological func-tions of HDL without changing circulating HDL choles-terol levels. Thus, HDL-targeting therapy has significant atheroprotective potential, as it uses lipid transporter-targeting agents, and may prove to be a therapeutic tool for atherosclerotic cardiovascular diseases.

High density lipoproteins and type 2 diabetes:Emerging concepts in their relationship

Patients with type 2 diabetes mellitus(T2DM) frequently exhibit macrovascular complications of atherosclerotic cardiovascular(CV) disease. High density lipoproteins(HDL) are protective against atherosclerosis. Low levels of HDL cholesterol(HDL-C) independently contribute to CV risk. Patients with T2 DM not only exhibit low HDL-C, but also dysfunctional HDL. Furthermore, low concentration of HDL may increase the risk for the development of T2 DM through a decreased β cell survival and secretory function. In this paper, we discuss emerging concepts in the relationship of T2 DM with HDL.

SNP Detection of High Density Lipoprotein Binding Protein Gene (HBP) and Its Correlations with Growth Traits in Largemouth Bass(Micropterus salmoides)

High density lipoprotein binding protein （HBP） plays an important role in lipid metabolism of animals. Lipids are indispensable energy materials for fi- shes, especially for carnivorous fishes with low utilization efficiency of carbohydrates. The single nucleotide polymorphism （SNP） of HBP gene may affect the fat metabolism, thereby exerting an effect on the growth traits of largemouth bass （Micropterus salmoides）. Investigating the correlations between SNP and growth traits can provide candidate markers for molecular marker-assisted selection. In this study, partial genomic fraganents of HBP gene （ GenBank accession number： KF652241 ） were amplified based on the sequences of an available contig in the EST-SNP database of largemouth bass. Three SNP mutation loci were identified in the 3＇ non-ceding region of HBP gene by direct sequencing, including H1 （G ＋ 2782T）, 142 （T ＋ 2817C） and H3 （G ＋ 2857A）. Three SNP loci of 165 randomly selected largemouth bass individuals were detected and genotyped by SnaPshot assay. Genetic structure was analyzed by POPGENE32 software. By using spssl7.0 software, a general linear model （GLM） was established for correlation analysis between different genotypes at SNP loci of HBP gene and various growth traits. The results showed that three SNP loci were in Hardy-Weinberg equilibrium state. To be specific, loci H1 and H2 formed two haplotypes （ A and B）, and three geno- types （AA, AB, and BB） were observed; loci H1, H2 and H3 formed six diplotypes （DI, I）2, D3, D4, D5 and D6）. According to the correlations between dif- ferent genotypes and various growth traits, the body weight and total length of largemouth bass individuals with genotype BB were significantly higher than those of individuals with genotype AB （ P 〈 0.05 ） ; the body weight and total length of largemouth bass individuals with diplotype D6 were significantly higher than those of individuals with diplotype D4 （P 〈0.05）. In this study, SNP markers correlated with growth traits were obtained in the 3＇ non-coding region ofHBP gene in large-mouth bass, which could be used as candidate genetic markers for subsequent molecular marker-assisted selection breeding of largemouth bass.

High density lipoprotein and cardiovascular diseases

Several epidemiological studies have clearly shown that low plasma levels of high density lipoprotein cholesterol (HDL-C) represent a cardiovascular disease (CVD) risk factor. However, it is unclear if there is a causal association between HDL-C concentration and CVD. A recent study published in the Lancet, which performed two Mendelian randomization analyses, showed that increased HDL-C levels were not associated with a decreased risk of myocardial infarction. These findings, together with the termination of the niacin-based AIM-HIGH trial and the discontinuation of cholesteryl ester transfer protein inhibitor dalcetrapib, challenge the concept that raising of plasma HDL-C will uniformly translate into reductions in CVD risk. HDL particles exhibit several anti-atherosclerotic properties, such as anti-inflammatory and anti-oxidative activities and cellular cholesterol efflux activity. Furthermore, HDL particles are very heterogeneous in terms of size, structure, composition and metabolism. HDL functionality may be associated more strongly with CVD risk than the traditional HDL-C levels. More research is needed to assess the association of the structure of HDL particle with its functionality and metabolism.

High-density lipoprotein as a potential carrier for delivery of a lipophilic antitumoral drug into hepatoma cells

AIM: To investigate the possibility of recombinant highdensity lipoprotein (rHDL) being a carrier for delivering antitumoral drug to hepatoma cells.METHODS: Recombinant complex of HDL and aclacinomycin(rHDL-ACM) was prepared by cosonication of apoproteins from HDL (Apo HDL) and ACM as well as phosphatidylcholine.Characteristics of the rHDL-ACM were elucidated by electrophoretic mobility, including the size of particles,morphology and entrapment efficiency. Binding activity of rHDL-ACM to human hepatoma cells was determined by competition assay in the presence of excess native HDL. The cytotoxicity of rHDL-ACM was assessed by MTT method.RESULTS: The density range of rHDL-ACM was 1.063-1.210g/mL, and the same as that of native HDL. The purity of all rHDL-ACM preparations was more than 92%.Encapsulated efficiencies of rHDL-ACM were more than90%. rHDL-ACM particles were typical sphere model of lipoproteins and heterogeneous in particle size. The average diameter was 31.26±5.62 nm by measure of 110rHDL-ACM particles in the range of diameter of lipoproteins.rHDL-ACM could bind on SMMC-7721 cells, and such binding could be competed against in the presence of excess native HDL. rHDL-ACM had same binding capacity as native HDL. The cellular uptake of rHDL-ACM by SMMC-7721 hepatoma cells was significantly higher than that of free ACM at the concentration range of 0.5-10 μg/mL(P＜0.01). Cytotoxicity of rHDL-ACM to SMMC-7721 cells was significantly higher than that of free ACM at concentration range of less than 5 μg/mL (P＜0.01) and IC50 of rHDL-ACM was lower than IC50 of free ACM(1.68 nmol/L vs3 nmol/L). Compared to L02 hepatocytes,a normal liver cell line, the cellular uptake of rHDL-ACM by SMMC-7721 cells was significantly higher (P＜0.01) and in a dose-dependent manner at the concentration range of 0.5-10 μg/mL. Cytotoxicity of the rHDL-ACM to SMMC-7721 cells was significantly higher than that to L02 cells at concentration range of 1-7.5 μg/mL (P＜0.01). IC50 for SMMC-7721 cells (1.68 nmol/L) was lower than that for L02 cells (5.68 nmol/L), showing a preferential cytotoxicity of rHDL-ACM for SMMC-7721 cells.CONCLUSION: rHDL-ACM complex keeps the basic physical and biological binding properties of native HDL and shows a preferential cytotoxicity for SMMC-7721hepatoma to normal L02 hepatocytes. HDL is a potential carrier for delivering lipophilic antitumoral drug to hepatoma cells.

High Density Lipoprotein Phospholipids as a Marker of Coronary Heart Disease of Shen-Yang Deficiency Syndrome

Objective: To seek a new biochemical index for diagnosis of coronary heart disease (CHD) of shen-Yang deficiency syndrom (CHD-SYD). Methods: Sixty-one patients with CHD were divided into 3 groups according to their TCM Syndrome type, 10 patients in the group without Xin-Qi deficiency (Group A), 25 in the group with Xin-Qi deficiency but without Shen-Yang deficiency (Group B) and 26 in the group both with Xin-Qi deficiency and Shen-Yang deficiency (Group C). Levels of 17-hydroxy-corticoste-roid in urine (urinary 17-OHCS) per 24 hrs, and serum level of high density lipoprotein cholesterol (HDL-C) and high density lipoprotein phospholipid (HDL-PL) in them were determined in synchrostep and compared with those in the control group of 23 healthy aged persons, urinary 17-OHCS per 24 hrs was taken as the diagnostic standard to screen a new index for diagnosis of Shen-Yang deficiency Syndrome, and preliminary appraisal to the index was made. Results: Serum HDL-PL in the CHD-SYD patients( Group C) was 616+157 mg/L, which was obviously lower than that in the patients of Group A and B. With low HDL-PL(<650 mg/L) used as the index to diagnose CHD-SYD, the sensitivity was 73%, the specificity 86% and the accuracy 80%. Conclusion: HDL-PL <650 mg/L could be adopted as an index for CHD-SYD diagnosis, which is simple and practical.

Effect of low high-density lipoprotein levels on mortality of septic patients: A systematic review and meta-analysis of cohort studies

BACKGROUND:An increase in high-density lipoprotein(HDL)is well associated with a decreased cardiovascular risk,especially atherosclerosis.Recent studies suggest that lower levels of HDL may also be associated with an increased risk of sepsis and an increased rate of mortality in septic patients.However,this conclusion remains controversial.METHODS:MEDLINE,EMBASE,and CENTRAL databases were searched from inception to September 30,2019.All studies were conducted to evaluate the correlation of lipoprotein levels and the risk and outcomes of sepsis in adult patients.The primary outcomes were the risk and mortality of sepsis.RESULTS:Seven studies comprising 791 patients were included.Lower levels of HDL had no marked relevance with the risk of sepsis(odds radio[OR]for each 1 mg/dL increase,0.94;95%CI 0.86–1.02;P=0.078),whereas lower HDL levels were related to an increased mortality rate in septic patients(OR for below about median HDL levels,2.00;95%CI 1.23–3.24;P=0.005).CONCLUSION:This meta-analysis did not reveal a signifi cant association between lower HDL levels and an increase in the risk of sepsis,whereas it showed that lower HDL levels are associated with a higher mortality rate in septic adult patients.These findings suggest that HDL may be considered as a promising factor for the prevention and treatment of sepsis in the future.

The pleiotropic vasoprotective functions of high density lipoproteins(HDL)

The pleiotropic functions of circulating high density lipoprotein（HDL） on peripheral vascular health are well established. HDL plays a pivotal role in reverse cholesterol transport and is also known to suppress inflammation,endothelial activation and apoptosis in peripheral vessels. Although not expressed in the central nervous system, HDL has nevertheless emerged as a potential resilience factor for dementia in multiple epidemiological studies. Animal model data specifically support a role for HDL in attenuating the accumulation of P-amyloid within cerebral vessels concomitant with reduced neuroinflammation and improved cognitive performance. As the vascular contributions to dementia are increasingly appreciated, this review seeks to summarize recent literature focused on the vasoprotective properties of HDL that may extend to cerebral vessels, discuss potential roles of HDL in dementia relative to brainderived lipoproteins, identify gaps in current knowledge, and highlight new opportunities for research and discovery.

High-density lipoproteins:an emerging target in the prevention of cardiovascular disease

高密度的脂蛋白(HDL ) 很好被建立了免于动脉粥样硬化患者的发展心血管的疾病。除了反向的胆固醇运输的提升， HDL 拥有可以在动脉的墙上贡献他们的有益的影响的很多个另外的功能的性质，变得明显。很多令人激动的治疗学的策略被开发了免于动脉粥样硬化患者的发展的那目标 HDL 和它的能力匾。这篇论文将考察 HDL 的功能的性质的提升怎么与确定的疾病在病人禁止动脉粥样硬化患者匾和 stabilises 损害的形成。

Bone and high-density lipoprotein:The beginning of a beautiful friendship

There is a tight link between bone and lipid metabolic pathways.In this vein,several studies focused on the exploration of high-density lipoprotein(HDL)in the pathobiology of bone diseases,with emphasis to the osteoarthritis(OA)and osteoporosis,the most common bone pathologies.Indeed,epidemiological and in vitro data have connected reduced HDL levels or dysfunctional HDL with cartilage destruction and OA development.Recent studies uncovered functional links between HDL and OA fueling the interesting hypothesis that OA could be a chronic element of the metabolic syndrome.Other studies have linked HDL to bone mineral density.Even though at epidemiological levels the results are conflicting,studies in animals as well as in vitro experiments have shown that HDL facilitates osteoblastogensis and bone synthesis and most probably affects osteoclastogenesis and osteoclast bone resorption.Notably,reduced HDL levels result in increased bone marrow adiposity affecting bone cells function.Unveiling the mechanisms that connect HDL and bone/cartilage homeostasis may contribute to the design of novel therapeutic agents for the improvement of bone and cartilage quality and thus for the treatment of related pathological conditions.

Metabolism of high density lipoproteins in liver cancer

Liver plays a vital role in the production and catabolism of plasma lipoproteins. It depends on the integrity of cellular function of liver, which ensures homeostasis of lipid and lipoprotein metabolism. When liver cancer occurs these processes are impaired and high-density lipoproteins are changed.

Higher testosterone levels are associated with increased highdensity lipoprotein cholesterol in men with cardiovascular disease： results from the Massachusetts Male Aging Study

Aim： To study the relationship between circulating androgens （total testosterone [TT], free testosterone [IT] and dihydrotestosterone [DHT]） and high-density lipoprotein cholesterol （HDL-C） in men with and without cardiovascular disease （CVD）. Methods： Cross-sectional analyses included 1 661 baseline samples from the Massachusetts Male Aging Study （MMAS）, a population-based cohort of men ages 40-70 years. Serum hormones were measured by radioimmunoassay and HDL-C was determined following precipitation of the lower density lipoproteins. CVD was determined by self-report. Analyses were performed using multiple linear regression. Results： TT and HDL-C were positively correlated in the entire sample （r = 0.11, P = 0.0001）. After adjusting for confounders, we found this relationship was mostly limited to the 209 men with CVD. Among men with CVD, TT （P = 0.0004）, iT （P = 0.0172） and DHT （P = 0.0128） were all positively correlated with HDL-C, whereas in men without CVD only TT correlated with HDL-C （P = 0.0099）. Conclusion： Our results suggest that if androgens contribute to CVD in middle-aged men, the effect is not related to a suppressive effect of endogenous T on HDL-C. （Asian JAndrol 2008 Mar; 10： 193-200）

Role of sphingosine 1-phosphate in anti-atherogenic actions of high-density lipoprotein

The reverse cholesterol transport mediated by highdensity lipoprotein(HDL)is an important mechanism for maintaining body cholesterol,and hence,the crucial anti-atherogenic action of the lipoprotein.Recent studies,however,have shown that HDL exerts a variety of anti-inflammatory and anti-atherogenic actions independently of cholesterol metabolism.The present review provides an overview of the roles of sphingosine 1-phosphate(S1P)/S1P receptor and apolipoprotein A-I/ scavenger receptor class B typeⅠsystems in the antiatherogenic HDL actions.In addition,the physiological significance of the existence of S1P in the HDL particles is discussed.

OXIDIZED HIGH-DENSITY LIPOPROTEIN PROMOTES MATURATION AND MIGRATION OF BONE MARROW DERIVED DENDRITIC CELLS FROM C57BL/6J MICE

Objective To explore the influence of oxidized high-density lipoprotein (oxHDL) on the maturation and migration of bone marrow-derived dendritic cells (BMDCs) from C57BL/6J mice. Methods The C57BL/6J mice bone marrow cell suspension was prepared and purified. Recombinant granulocyte-macrophage colony-stimulating factor (rmGM-CSF) and recombinant interleukin-4 (rmIL-4) were used to promote monocytes to differentiate and suppress lymphocytes. Then 50 μg/mL oxHDL was added to stimulate BMDCs, using 50 μg/mL high-density lipoprotein (HDL) as homologous protein control, PBS as negative control, and 1 μg/mL lipopolysaccharide (LPS) as positive control. The CD86 and MHCII expression rates were detected with fluorescence-activated cell sorting (FACS). Liquid scintillation counting (LSC) was used in mixed lymphocyte reactions (MLRs) to reflect the ability of BMDCs in stimulating the proliferation of homologous T cells. Levels of cytokines IL-12 and IL-10 were detected by ELISA. The cell migration was evaluated with the transwell system. Results Compared with PBS group, the expressions of CD86 and MHCII, counts per minute of MLRs, secretion of IL-12 and IL-10, and number of migrated cells in oxHDL group and LPS group significantly increased (all P < 0.05), while the increment was less in oxHDL group than LPS group. The number of migrated cells in oxHDL group was about twice of that in HDL group. Conclusion OxHDL may promote the maturation and migration of BMDCs in vitro.

Pleiotropic effects of apolipoprotein A-Ⅱ on high-density lipoprotein functionality, adipose tissue metabolic activity and plasma glucose homeostasis

Apolipoprotein A-Ⅱ(APOA-Ⅱ) is the second most abundant apolipoprotein of high-density lipoprotein(HDL)synthesized mainly by the liver and to a much lesser extent by the intestine. Transgenic mice overexpressing human APOA-Ⅱ present abnormal lipoprotein composition and are prone to atherosclerosis, though in humans the role for APOA-Ⅱ in coronary heart disease remains controversial. Here, we investigated the effects of overexpressed APOA-Ⅱ on HDL structure and function, adipose tissue metabolic activity, glucose tolerance and insulin sensitivity. C57BL/6 mice were infected with an adenovirus expressing human APOA-Ⅱ or a control adenovirus Ad GFP, and five days post-infection blood and tissue samples were isolated. APOA-Ⅱ expression resulted in distinct changes in HDL apoproteome that correlated with increased antioxidant and anti-inflammatory activities. No effects on cholesterol efflux from RAW 264.7 macrophages were observed. Molecular analyses in white adipose tissue(WAT) indicated a stimulation of oxidative phosphorylation coupled with respiration for ATP production in mice overexpressing APOA-Ⅱ. Finally, overexpressed APOA-Ⅱ improved glucose tolerance of mice but had no effect on the response to exogenously administered insulin. In summary, expression of APOA-Ⅱ in C57BL/6 mice results in pleiotropic effects with respect to HDL functionality, adipose tissue metabolism and glucose utilization, many of which are beneficial to health.

High-density Lipoprotein Cholesterol and In-hospital Mortality in Patients with Acute Aortic Dissection

The association between high-density lipoprotein cholesterol（HDL-C） and mortality in patients with acute aortic dissection（AAD） is unclear. From January 2007 to January 2014, a total of 928 consecutive AAD patients who were admitted within 48 h after the onset of symptoms were enrolled in the study. Patients were divided into two groups according to whether serum HDL-C level was below the normal lower limit or not. The Cox proportional hazard regression model was used to identify the predictive value of HDL-C for in-hospital mortality in patients with AAD. As compared with normal HDL-C group（n=585）, low HDL-C group（n=343） had lower levels of systolic blood pressure and hemoglobin and higher levels of leukocyte, alanine aminotransferase, blood glucose, blood urea nitrogen, creatinine and urea acid. Low HDL-C group had significantly higher in-hospital mortality than normal HDL-C group（21.6% vs. 12.6%, log-rank=10.869, P=0.001）. After adjustment for baseline variables including demographics and biologic data, the increased risk of in-hospital mortality in low HDL-C group was substantially attenuated and showed no significant difference（adjusted hazard ratio, 1.23; 95% confidence interval, 0.86–1.77; P=0.259）. Low HDL-C is strongly but not independently associated with in-hospital mortality in patients with AAD.

Associations of High Density Lipoprotein Cholesterol and Framingham Cardiovascular Risk with Diabetic Retinopathy in African Type 2 Diabetics

Objectives: To assess the associations of high density lipoprotein cholesterol (HDL-C) and Framingham cardiovascular (CVD) with diabetic retinopathy (DR). Methods: A cross-sectional study of random sample of 200 T2DM Central Africans. Sociobiographical, laboratory and eye examination main outcome measures were investigated using Tertiles of HDL-C (stratification = lowest 10% were the significant independent determinants for DR. In the highest HDL-C group, smoking status and 10-year Framingham risk ≥ 10% were the significantly independent determinants for DR. In 10-year Framingham risk ≥ 10% group, smoking status, insulin resistance and increasing levels of HDL-C were the significantly independent determinants for DR. Conclusion: DR and VD remain a public health problem in T2DM Central Africans. Some Central Africans with DR and VD appear to have higher HDL-C than T2DM Central Africans without DR and VD. HDL-C in T2DM patients with DR, may be tightly controlled by genetic factors (black Bantu ethnicity) than the other lipoproteins as reported among Indians, African-Americans, and Japanese individuals. The most preventable environmental risk factors for DR were smoking status, global cardiovascular disease risk, insulin resistance and oxidative stress.

Research progress of monocyte/high density lipoprotein ratio in cardiovascular diseases

In recent years,monocyte to high density lipoprotein cholesterol ratio(MHR)has attracted wide attention as a new marker of inflammatory response.This indicator includes two aspects:inflammatory response and lipid accumulation,which are the two most basic characteristics of Atherosclerosis(AS).AS is closely related to the occurrence of Cardiovascular diseases(CVD).A large number of existing studies have confirmed that MHR is an inflammatory marker that can dynamically reflect the trend of inflammation,can reflect the chronic inflammatory response in blood vessels,and can evaluate the occurrence,development and prognosis of cardiovascular disease in a non-invasive manner.This article reviews recent studies on the role of monocytes and high-density lipoproteins in chronic inflammation of blood vessels,as well as the current status of research on MHR and cardiovascular disease in the light of recent literature.

Risk factors for low high-density lipoprotein among Asian Indians in the United States

AIM To examine the differences in metabolic risk factors(RFs) by gender in the Asian Indian(AI) population in the United States. METHODS Using cross-sectional data from 1038 randomly selected Asian Indians, we investigated the relationship between metabolic syndrome(Met S) RFs, cardiovascular disease,and diabetes. RESULTS A greater percent of women in this group had increased waist circumference and low high density lipoprotein(HDL) levels than men, but AI males had increased blood glucose, increased blood pressure, and increased triglycerides compared to females. Those individuals who met the Met S criteria had increased cardiovascular disease. One of the biggest single RFs for cardiovascular disease and diabetes reported in the literature for AIs is low HDL. CONCLUSION Our results show that lack of knowledge about diabetes, low physical activity, increased body mass index, and age were the factors most significantly correlated with low HDL in this population. Future studies and prospective trials are needed to further elucidate causes of the Met S and diabetes in AIs.