Apolipoprotein A-V gene therapy for disease prevention/treatment:a critical analysis

Apolipoprotein（apo） A-V is a novel member of the class of exchangeable apo＇s involved in triacylglycerol（TG）homeostasis.Whereas a portion of hepatic-derived apoA-V is secreted into plasma and functions to facilitate lipoprotein Iipase-mediated TG hydrolysis,another portion is recovered intracellularly,in association with cytosolic lipid droplets.Loss of apo A-V function is positively correlated with elevated plasma TG and increased risk of cardiovascular disease.Single nucleotide polymorphisms（SNP） in the APOA5 locus can affect transcription efficiency or introduce deleterious amino acid substitutions.Likewise,rare mutations in APOA5 that compromise functionality are associated with increased plasma TG and premature myocardial infarction.Genetically engineered mouse models and human population studies suggest that,in certain instances,supplementation with wild type（WT） apoA-V may have therapeutic benefit.It is hypothesized that individuals that manifest elevated plasma TG owing to deleterious APOA5 SNPs or rare mutations would respond to WT apoA-V supplementation with improved plasma TG clearance.On the other hand,subjects with hypertriglyceridemia of independent origin（unrelated to apoA-V function） may not respond to apoA-V augmentation in this manner.Improvement in the ability to identify individuals predicted to benefit,advances in gene transfer technology and the strong connection between HTG and heart disease,point to apoA-V supplementation as a viable disease prevention / therapeutic strategy.Candidates would include individuals that manifest chronic TG elevation,have low plasma apoA-V due to an APOA5 mutation/polymorphism and not have deleterious mutations/polymorphisms in other genes known to influence plasma TG levels.

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.

Apolipoprotein A1,the neglected relative of Apolipoprotein E and its potential role in Alzheimer’s disease

Lipoproteins are multi-molecule assemblies with the primary function of transportation and processing of lipophilic substances within aqueous bodily fluids(blood,cerebrospinal fluid).Nevertheless,they also exert other physiological functions such as immune regulation.In particular,neurons are both sensitive to uncontrolled responses of the immune system and highly dependent on a controlled and sufficient supply of lipids.For this reason,the role of certain lipoproteins and their protein-component(apolipoproteins,Apo’s)in neurological diseases is perceivable.ApoE,for example,is well-accepted as one of the major risk factors for sporadic Alzheimer’s disease with a protective allele variant(ε2)and a risk-causing allele variant(ε4).ApoA1,the major protein component of high-density lipoproteins,is responsible for transportation of excess cholesterol from peripheral tissues to the liver.The protein is synthesized in the liver and intestine but also can enter the brain via the choroid plexus and thereby might have an impact on brain lipid homeostasis.This review focuses on the role of ApoA1 in Alzheimer’s disease and discusses whether its role within this neurodegenerative disorder is specific or represents a general neuroprotective mechanism.

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.

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.

Expression of human hepatic lipase negatively impacts apolipoprotein A-Ⅰ production in primary hepatocytes from Lipc-null mice

This study aimed to examine whether expression of human hepatic lipase（hHL） exerted an intracellular effect on hepatic production of apolipoprotein（apo） A-I.The levels of secreted and cell-associated apoA-I were contrasted between primary hepatocytes isolated from Lipc-nuW and C57BL/6 mice,and between Lipc-nuW hepatocytes transfected with either hHL-encoding or control adenovirus.An HSPG-binding deficient hHL protein（hHLmt） was used to determine the impact of cell surface binding on HL action.Accumulation of apoA-I in conditioned media of primary hepatocytes isolated from Lipc-nuW mice was increased as compared to that from C57BL/6 mice.Metabolic labeling experiments showed that secretion of ＇＇S-apoA-I from Lipc-nuW cells was significantly higher than that from C57BL/6 cells.Expression of hHL in Lipc-nuW hepatocytes,through adenovirus-mediated gene transfer,resulted in decreased synthesis and secretion of ＇S-apoA-I,but not S-apoE,as compared with cells transfected with control adenovirus.Expression of HSPG-binding deficient hHLmt in Lipc-nuW cells also exerted an inhibitory effect on apoA-I production,even though hHLmt displayed impaired exit from the endoplasmic reticulum as compared with hHL.Subcellular fractionation revealed that expression of hHL or hHLmt led to increased microsome-association of apoA-I relative to non-transfected control.Expression of hHL negatively impacts hepatic production of apoA-I.

Low-density lipoprotein receptor-related protein 2(LRP2)is required for lipid export in the midgut of the migratory locust,Locusta migratoria

Low-density lipoprotein receptor-related protein 2(LRP2)is a multifunctional endocytic receptor expressed in epithelial cells.In mammals,it acts as an endocytic receptor that mediates the cellular uptake of cholesterol-containing apolipoproteins to maintain lipid homeostasis.However,little is known about the role of LRP2 in lipid homeostasis in insects.In the present study,we investigated the function of LRP2 in the migratory locust Locusta migratoria(LmLRP2).The mRNA of LmLRP2 is widely distributed in various tissues,including integument,wing pads,foregut,midgut,hindgut,Malpighian tubules and fat body,and the amounts of LmLRP2 transcripts decreased gradually in the early stages and then increased in the late stages before ecdysis during the nymphal developmental stage.Fluorescence immunohistochemistry revealed that the LmLRP2 protein is mainly located in cellular membranes of the midgut and hindgut.Using RNAi to silence LmLRP2 caused molting defects in nymphs(more than 60%),and the neutral lipid was found to accumulate in the midgut and surface of the integument,but not in the fat body,of dsLmLRP2-treated nymphs.The results of a lipidomics analysis showed that the main components of lipids(diglyceride and triglyceride)were significantly increased in the midgut,but decreased in the fat body and hemolymph.Furthermore,the content of total triglyceride was significantly increased in the midgut,but markedly decreased in the fat body and hemolymph in dsLmLRP2-injected nymphs.Our results indicate that LmLRP2 is located in the cellular membranes of midgut cells,and is required for lipid export from the midgut to the hemolymphand fat body in locusts.

Overexpression of low-density lipoprotein receptor prevents neurotoxic polarization of astrocytes via inhibiting NLRP3 inflammasome activation in experimental ischemic stroke

Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury.Low-density lipoprotein receptor,a classic cholesterol regulatory receptor,has been found to inhibit NLR family pyrin domain containing protein 3(NLRP3)inflammasome activation in neurons following ischemic stroke and to suppress the activation of microglia and astrocytes in individuals with Alzheimer’s disease.However,little is known about the effects of low-density lipoprotein receptor on astrocytic activation in ischemic stroke.To address this issue in the present study,we examined the mechanisms by which low-density lipoprotein receptor regulates astrocytic polarization in ischemic stroke models.First,we examined low-density lipoprotein receptor expression in astrocytes via immunofluorescence staining and western blotting analysis.We observed significant downregulation of low-density lipoprotein receptor following middle cerebral artery occlusion reperfusion and oxygen-glucose deprivation/reoxygenation.Second,we induced the astrocyte-specific overexpression of low-density lipoprotein receptor using astrocyte-specific adeno-associated virus.Low-density lipoprotein receptor overexpression in astrocytes improved neurological outcomes in middle cerebral artery occlusion mice and reversed neurotoxic astrocytes to create a neuroprotective phenotype.Finally,we found that the overexpression of low-density lipoprotein receptor inhibited NLRP3 inflammasome activation in oxygen-glucose deprivation/reoxygenation injured astrocytes and that the addition of nigericin,an NLRP3 agonist,restored the neurotoxic astrocyte phenotype.These findings suggest that low-density lipoprotein receptor could inhibit the NLRP3-meidiated neurotoxic polarization of astrocytes and that increasing low-density lipoprotein receptor in astrocytes might represent a novel strategy for treating cerebral ischemic stroke.

Carbamylated lipoproteins in diabetes

Diabetic dyslipidemia is characterized by quantitative and qualitative abnormalities in lipoproteins.In addition to glycation and oxidation,carbamylation is also a post-translational modification affecting lipoproteins in diabetes.Patients with type 2 diabetes(T2D)exhibit higher levels of carbamylated low-density lipoproteins(cLDL)and high-density lipoproteins(cHDL).Accumulating evidence suggests that cLDL plays a role in atherosclerosis in diabetes.cLDL levels have been shown to predict cardiovascular events and all-cause mortality.cLDL facilitates immune cell recruitment in the vascular wall,promotes accumulation of lipids in macrophages,and contributes to endothelial dysf-unction,endothelial nitric oxide-synthase(eNOS)inactivation and endothelial repair defects.Lastly,cLDL induces thrombus formation and platelet aggregation.On the other hand,recent data have demonstrated that cHDL serum level is independently associated with all-cause and cardiovascular-related mortality in T2D patients.This relationship may be causative since the atheroprotective properties of HDL are altered after carbamylation.Thus,cHDL loses the ability to remove cholesterol from macrophages,to inhibit monocyte adhesion and recruitment,to induce eNOS activation and to inhibit apoptosis.Taken together,it seems very likely that the abnormalities in the biological functions of LDL and HDL after carbamylation contribute to atherosclerosis and to the elevated cardiovascular risk in diabetes.

Nanotechnologies meeting natural sources:Engineered lipoproteins for precise brain disease theranostics

Biological nanotechnologies have provided considerable opportunities in the management of malignancies with delicate design and negligible toxicity,from preventive and diagnostic to therapeutic fields.Lipoproteins,because of their inherent blood-brain barrier permeability and lesion-homing capability,have been identified as promising strategies for high-performance theranostics of brain diseases.However,the application of natural lipoproteins remains limited owing to insufficient accumulation and complex purification processes,which can be critical for individual therapeutics and clinical translation.To address these issues,lipoprotein-inspired nano drug-delivery systems(nano-DDSs),which have been learned from nature,have been fabricated to achieve synergistic drug delivery involving site-specific accumulation and tractable preparation with versatile physicochemical functions.In this review,the barriers in brain disease treatment,advantages of state-of-the-art lipoprotein-inspired nano-DDSs,and bio-interactions of such nano-DDSs are highlighted.Furthermore,the characteristics and advanced applications of natural lipoproteins and tailor-made lipoprotein-inspired nano-DDSs are summarized.Specifically,the key designs and current applications of lipoprotein-inspired nano-DDSs in the field of brain disease therapy are intensively discussed.Finally,the current challenges and future perspectives in the field of lipoprotein-inspired nano-DDSs combined with other vehicles,such as exosomes,cell membranes,and bacteria,are discussed.

Lipoprotein(a)and Benefit of PCSK9 Inhibition in Emergency Complex Higher-risk and Indicated Patients

Objective There is a large population of patients classified as complex higher-risk and indicated patients(CHIPs)in China with a poor prognosis.The treatment of these patients is complex and challenging,especially when acute cardiac events occur,such as acute coronary syndrome(ACS)or heart failure.Pharmacotherapy and some mechanical circulatory support(MCS)therapeutic devices can provide stable hemodynamic support for CHIPs-percutaneous coronary intervention(PCI).LDL-C is an important pathogenic factor in atherosclerosis,and the target of blood lipid control.Recent studies have revealed that lipoprotein(a)[Lp(a)],which is formed when a covalent bond between apolipoprotein(a)and apolipoprotein B-100 is made,produces an LDL-like particle.This particle is an independent risk factor for the development of atherosclerosis,and is closely correlated to stent thrombosis and restenosis.Furthermore,this requires active intervention.PCSK9 inhibitors have been used in lipid-lowering treatment,and preventing atherosclerosis.The present study explores the efficacy of PCSK9 inhibitors in CHIPs-ACS,and the association between the change in Lp(a)and survival after 2 years of follow-up.Methods The present real-world,prospective control study enrolled 321 CHIPs-ACS who underwent emergency PCI from August 2019 to November 2020,and these patients were followed up for 2 years.These patients were divided into two groups:PCSK9 group(n=161)given the combined PCSK9 inhibitor(140 mg of evolocumab every 2 weeks)and statins-based therapy,and SOC group(n=160)treated with statin-based lipid-lowering therapy alone.Then,the change in lipid index was measured,and the cardiovascular(CV)event recurrence rate was evaluated after one month and 2 years.Afterwards,the contribution of serum lipid parameters,especially the Lp(a)alteration,in patients with earlier initiation of the PCSK9 inhibitor to the CV outcome was analyzed.Results The LDL-C level was significantly reduced in both groups:52.3%in the PCSK9 group and 32.3%(P<0.001)in the SOC group.It is noteworthy that the Lp(a)level decreased by 13.2%in the PCSK9 group,but increased by 30.3%in the SOC group(P<0.001).Furthermore,the number of CV events was not significantly different between the PCSK9 and SOC groups after the 2-year follow-up period.In the PCSK9 group,the Lp(a)reduction was associated with the baseline Lp(a)levels of the patients(r2=−0.315,P<0.001).Moreover,the decrease in Lp(a)contributed to the decline in CV events in patients who received ACS CHIPs-PCI,and the decrease in Lp(a)level was independent of the LDL-C level reduction.Conclusion The early initiation of PCSK9 inhibitors can significantly reduce the LDL-C and Lp(a)levels in ACS CHIPs-PCI.However,further studies are needed to confirm whether PCSK9 inhibitors can reduce the incidence of CV disease in CHIPs.

Comparison of the effects of 3 kinds of oils rich in omega-3 polyunsaturated fatty acids on glycolipid metabolism and lipoprotein subfractions

Dietary omega-3 polyunsaturated fatty acids(ω-3 PUFAs)can be classifi ed into animal-and plant-derivedω-3 PUFAs.Patients with type 2 diabetes(T2DM)are frequently accompanied by dyslipidemia,which is closely related to the high-density lipoprotein(HDL-C)subfractions change.This study aimed to determine the effects of different sourcesω-3 PUFAs on glucolipid metabolism and lipoprotein subfractions in T2DM with dyslipidemia.Ninety T2DM patients with dyslipidemia were randomly assigned to take 3 g/day fi sh oil(FO,containing eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)),3 g/day perilla oil(PO,containingα-linolenic acid(ALA)),or 3 g/day blend oil(BO,containing EPA,DHA and ALA)for 3 months.90 patients completed the intervention.There was a significant reduction of glycated hemoglobin(HbA1c)in all the groups.The triglycerides(TG)in the FO group were signifi cantly different with a group×time interaction(P=0.043),which was higher compared with the other two groups.The serum small HDL-C subfractions in the PO group was higher and the serum large HDL-C subfractions in the PO group was lower than those in the BO and FO groups.Plant-derivedω-3 PUFAs are more effective at controlling blood glucose than animal-derivedω-3 PUFAs.However,animal-derivedω-3 PUFAs have a signifi cant lowering effect on TG compared with plant-derivedω-3 PUFAs.Particularly,large HDL-C subfractions after animal-derivedω-3 PUFAs intake were higher than plant-derivedω-3 PUFAs intake;while small HDL-C subfractions were lower.Both the animal-and plant-derivedω-3 PUFAs have practical value in improving glucose and lipids metabolism in T2DM patients with dyslipidemia.

Diagnostic and prognostic implications of non-high-density lipoprotein cholesterol and homocysteine levels for cognitive impairment in thalamic infarction

BACKGROUND Patients with thalamic infarction experience abnormal blockages of multinuc-leated vessels,affecting the body and thereby the thalamus.Most patients with thalamic infarction have an adverse prognosis,which seriously affects their safety.Therefore,it is essential to analyze the independent risk factors that influence the prognosis of patients with thalamic infarction and develop corresponding preventive measures.AIM To explore the effect of non-high-density lipoprotein cholesterol(non-HDL-C)and Homocysteine(Hcy)levels in cognitive impairment in thalamic infarction.METHODS From March 2019 to March 2022,80 patients with thalamic infarction were divided into a group with cognitive impairment[Montreal Cognitive Assessment(MoCA)score<26;35 patients]and a group with normal cognitive function(MoCA score of 26-30;45 patients)according to the MoCA score.In addition,50 healthy people in the same period were selected as the control group.A correlation between the non-HDL-C and Hcy levels and the MoCA score and receiver operating characteristic curve was observed,and the serum non-HDL-C and Hcy levels were analyzed for the diagnosis of cognitive impairment in patients with thalamic infarction.According to the Modified Rankin Scale(MRS)score,80 patients with thalamic infarction were divided into a good prognosis group(MRS score≤2)and a poor prognosis group(MRS score>2).RESULTS The non-HDL-C and Hcy levels were significantly higher in the group with cognitive impairment than in the group with normal cognitive function(P<0.05).There was no significant difference in the non-HDL-C level between the control group and the group with normal cognitive function(P>0.05).The MoCA scores of the group with cognitive impairment were significantly lower than those of the group with normal cognitive function and the control group(P<0.05).There was a significant difference between the control group and the group with normal cognitive function(P<0.05).The non-HDL-C and Hcy levels were correlated with the MoCA score(P<0.05),cognitive impairment[areas under the curve(AUC)=0.709,95%confidence interval(95%CI):0.599-0.816],the non-HDL-C level,and could predict cognitive impairment in patients with thalamic infarction(AUC=0.738,95%CI:0.618-0.859).Hcy combined with non-HDL-C levels can predict cognitive impairment in patients with thalamic infarction(AUC=0.769,95%CI:0.721-0.895).RESULTS There were 50 patients in the good prognosis group and 30 patients in the poor prognosis group.Compared with the good prognosis group,in the poor prognosis group,the National Institutes of Health Stroke Scale(NIHSS)score,non-HDL-C level,Hcy level,large-area cerebral infarction,atrial fibrillation,and activated partial prothrombin time were statistically significant(P<0.05).The non-HDL-C level,the Hcy level,the NIHSS score,extensive cerebral serum,and atrial fibrillation may all be independent risk factors for poor prognosis in patients with thalamic infarction(P<0.05).CONCLUSION Non-HDL-C and Hcy levels are positively correlated with cognitive impairment in patients with thalamic infarction.Non-HDL-C and Hcy levels can be used in the diagnosis of cognitive impairment in patients with thalamic infarction,and the combined detection effect is better.The main factors affecting the prognosis of patients with thalamic infarction are the non-HDL-C level,the Hcy level,the NIHSS score,large-area cerebral infarction,and atrial fibrillation.Clinically,corresponding preventive measures can be formulated based on the above factors to prevent poor prognosis and reduce mortality.

Lipoprotein (a) Cut-Off in Chronic Kidney Disease Patients with a History of Cardiovascular Disease in Center Hospital University Souro SANOU, Burkina Faso

Patients living with chronic kidney disease (CKD) are at high risk of cardiovascular events. Our aim in this study was to assess the cut-off value for lipoprotein (a) (Lp(a)) in CKD patients with a history of cardiovascular disease (CVD). This was a cross-sectional study. Variables including age, sex, history of CVD, body mass index and CKD stage, were collected during CKD patient’s first admission in the nephrology dialysis department. Blood samples were collected for quantitative determination of Lp(a) by immunoturbidimetric method. They were divided into two groups: CKD patients without history of CVD and CKD patients with history of CVD. Fisher’s exact test was used to assess associations with a significance level of 0.05%. Area under the curve (AUC) and new cut-off value for Lp(a) were identified by drawing Receiver Operating Characteristic (ROC) curve. A total of seventy CKD patients with median age of 43 years [minimum-maximum = 15 - 78 years] were included. Patients with history of CVD were 65.71% (46/70). New Lp(a) cut-off point in CKD patients with history of CVD was 66.50 nmol/L [sensitivity, 87.00%;specificity, 58.30%;AUC = 0.727;p = 0.000]. ROC curve demonstrated good performance of Lp(a) to screen CKD patients with history of CVD. Further research is needed to determine an LPA gene polymorphism’s contribution to increasing risk for CVD at each kidney disease stage.

Liver as a new target organ in Alzheimer's disease:insight from cholesterol metabolism and its role in amyloid-beta clearance

Alzheimer's disease,the primary cause of dementia,is characterized by neuropathologies,such as amyloid plaques,synaptic and neuronal degeneration,and neurofibrillary tangles.Although amyloid plaques are the primary characteristic of Alzheimer's disease in the central nervous system and peripheral organs,targeting amyloid-beta clearance in the central nervous system has shown limited clinical efficacy in Alzheimer's disease treatment.Metabolic abnormalities are commonly observed in patients with Alzheimer's disease.The liver is the primary peripheral organ involved in amyloid-beta metabolism,playing a crucial role in the pathophysiology of Alzheimer's disease.Notably,impaired cholesterol metabolism in the liver may exacerbate the development of Alzheimer's disease.In this review,we explore the underlying causes of Alzheimer's disease and elucidate the role of the liver in amyloid-beta clearance and cholesterol metabolism.Furthermore,we propose that restoring normal cholesterol metabolism in the liver could represent a promising therapeutic strategy for addressing Alzheimer's disease.

The relationship between serum amyloid A and apolipoprotein A-I in high-density lipoprotein isolated from patients with coronary heart disease

Background Alteration in the protein composition of high-density lipoprotein （HDL） has been proposed as a mechanism for the development of coronary heart disease （CHD）.In HDL,an increase in serum amyloid A protein （SAA） accompanying the decrease in apolipoprotein A-I （apoA-I） has been found during the acute inflammation period.However,whether this phenomenon persists in CHD patients,a disease related to inflammation,is unknown.The purpose of the present study was to explore the relationship between SAA and apoA-I in HDL isolated from CHD patients.Methods Overall,98 patients with confirmed stable CHD and 90 control subjects matched for age and gender were enrolled in this case-control study.Potassium bromide （KBr） density gradient ultracentrifugation was used to isolate HDL from plasma.The levels of SAA and apoA-I in the HDL samples were detected by enzyme-linked immunosorbent assay kits.Pearson＇s correlation and general linear models were used in the analysis.Results Compared with controls,patients with CHD had a significant decrease in the amount of apoA-I （（14.21±8.44） μg/ml vs.（10.95±5.95） μg/ml,P =0.003） in HDL and a significant increase in the amount of log SAA （1.21±0.46 vs.1.51±0.55,P 〈0.00001）.Differences were independent of age,body mass index （BMI）,HDL cholesterol （HDL-C）,and other factors.An independently and statistically significant positive correlation between log SAA and apoA-I in HDL was observed only in the CHD group （β =2.0,P =0.026）.In the general linear model,changes in Iog（SAA）,age,age2,gender,BMI and HDL-C could explain a statistically significant 43% of the variance in apoA-I.Conclusions This study provides direct evidence for the first time that there was an independent positive correlation between log SAA and apoA-I in the HDL of CHD patients,indicating the alteration of protein composition in HDL.However,the question of whether this alteration in HDL is associated with impairment of HDL functions requires further research.

High-density lipoprotein associated factors apoA-I and serum amyloid A in Chinese non-diabetic patients with coronary heart disease

Background High-density lipoprotein cholesterol（HDL-C）levels are a strong,independent inverse predictor of coronary heart disease （CHD）.In this cross-sectional study we investigated the interrelationships between HDL-C and HDL relaled factors apolipoprotein A-I（apoA-I）and serum amyloid A（SAA）and the presence and extent of CHD in a population of Chinese patients with CHD. Methods Two hundred and twenty-four consecutive patients took part in this study.Demographic data were obtained from hospital records.Serum chemical concentrations were measured by standard laboratory methods.Reaults The concentrations of high-sensitive C-reactive protein（hsCRP）（median：1.85 mg/L）and SAP,（median：9.40 mg/L）were significantly higher in the CHD group（P〈0.05）,while concentrations of HDL-C（0.03±0.25）mmol/L）and apoA-I（（604.59±1 05.79）mmol/L）were significantly lower than those in the non-CHD group（P〈0.05）.The concentrations of apoA-l decreased with the increase in vascular damage.but the difference did not reach statistical significance.However, the concentrations of hsCRP and SAA increased with the increase in vascular damage.The unadjusted odd ratios（ORs）（CI） for apoA-I and SAA of the presence of CHD were 0.093（0.990-0.997）（P=0.00）and 2.571（1.029-6.424）（P〈0.05）,respectively.The association between elevated SAA and the presence of CHD was lost after adjusting for lipid status parameter concentrations.The associations between apoA-I.SAA and the extent of CHD remained strong,regardless of confounding variables.Conclusions Increased concentrations of SAA represent the inflammatory marker of the extent of coronary stenosis in patients with CHD.In contrast to SAA, the level of apoA-I was also associated with the presence of CHD, indicating that apoA-I was not only a marker of CHD presence but also a quantitative indicator of CHD extent.In short.determining the change apolipoprotein content within HDL particle is a more accurate and effective method to evaluate the impact of HDL on CHD.

Baseline HDL-C/apolipoprotein A-I ratio predicts the severity of coronary artery lesions in diabetic patients with acute coronary syndrome

Background A low high-density lipoprotein cholesterol(HDL-C)to apolipoprotein A-I(apo A-I)ratio which reflects a small HDL-C particle size is emerging as an important predictor of cardiovascular risks.This study aimed to determine the association of HDL-C/apo A-I ratio with the severity of coronary artery lesions in diabetic patients.Methods Observational study was conducted and 478 diabetic patients with acute coronary syndrome(ACS)were enrolled.Baseline serum levels of HDL-C,apo A-I,clinical and biochemical parameters were collected.All patients underwent coronary angiography to evaluate the severity of coronary artery disease(CAD)in terms of the number of stenotic coronary arteries(defined as a stenosis≥50%)and the calculated Gensini score.Patients were then divided into different subgroups according to the two categories:single-,double-or triple-vessel groups;and Gensini Score groups(lower≤4,middle:5-15,and upper≥16).Receiver operating characteristic curves(ROC)were conducted to evaluate the diagnostic values in identifying severe CAD lesions.The association between HDL-C/apo A-I ratio and CAD severity was determined by multivariate logistic regression analysis.Results Patients with triple-vessel lesions or upper Gensini score had more CAD risk factors such as older age,smoking,low HDL-C and elevated fasting blood glucose(FBG).A lower HDL-C/apo A-I ratio corresponded to more vessels stenoses and a higher Gensini score.Notably,HDL-C/apo A-I outperformed HDL-C or apo A-I alone in diagnosing severe CAD lesions in ROC analyses.Moreover,multivariate regression analyses revealed that after adjustment for traditional risk factors such as LDL-C,FBG and HAb1c,HDL-C/apo A-I ratio remained independently associated with the severity of CAD in diabetic patients with ACS(all P<0.05).Conclusions HDL-C/apo A-I may be a useful indicator for the severity of CAD in diabetic patients with ACS.

Role of PERK/eIF2α/CHOP Endoplasmic Reticulum Stress Pathway in Oxidized Low-density Lipoprotein Mediated Induction of Endothelial Apoptosis

Objective PERK/elF2/CHOP is a major signaling pathway mediating endoplasmic reticulum （ER） stress related with atherosclerosis. Oxidized LDL （ox-LDL） also induces endothelial apoptosis and plays a vital role in the initiation and progression of atherosclerosis. The present study was conducted to explore the regulatory effect of ox-LDL on PERK/elF2a/CHOP signaling pathway in vascular endothelial cells. Methods The effects of ox-LDL on PERK and p-elF2a protein expression of primary human umbilical vein endothelial cells （HUVECs） were investigated by Western blot analysis. PERK gene silencing and selective elF2a phosphatase inhibitor, salubrinal were used to inhibit the process of ox-LDL induced endothelial cell apoptosis, caspase-3 activity, and CHOP mRNA level. Results Ox-LDL treatment significantly increased the expression of PERK, PERK-mediated inactivation of elF2a phosphorylation, and the expression of CHOP, as well as the caspase-3 activity and apoptosis. The effects of ox-LDL were markedly decreased by knocking down PERK with stable transduction of lentiviral shRNA or by selective elF2a phosphatase inhibitor, salubrinal. Conclusion This study provides the first evidence that ox-LDL induces apoptosis in vascular endothelial cells mediated largely via the PERK/elF2a/CHOP ER-stress pathway. It adds new insights into the molecular mechanisms underlying the pathogenesis and progression of atherosclerosis.