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.

Influence of Oxidized Low Density Lipoprotein on the Proliferation of Human Artery Smooth Muscle Cells in vitro

The effects of oxidized low density lipoprotein （ox-LDL） on the proliferation of cultured human vascular smooth muscle cells （vSMC） were investigated in vitro. By using NaBr density gradient centrifugation, LDL was isolated and purified from human plasma. Ox-LDL was produced from LDL by being incubated with CuSO4. ox-LDL was then added to the culture medium at different concentrations （35, 60, 85, 110, 135 and 160μg/mL） for 7 days. The influence of ox-LDL on vSMC proliferation was observed in growth curve, mitosis index, and in situ determination of apoptosis. The data were analyzed with SPSS 10.0 software. The results showed that the ox-LDL produced in vitro had a good purity and optimal oxidative degree, which was similar to the intrinsic ox-LDL in atherosclerotic plaque, ox-LDL at a concentration of 35 μg/mL demonstrated the strongest proliferation inducement, and at a concentration of 135 μg/mL, ox-LDL could inhibit the growth of vSMC. ox-LDL at concentrations of 35 and 50 μg/mL presented powerful mitotic trigger, and with the increase of ox-LDL concentration, the mitotic index of vSMC was decreased gradually, ox-LDL at higher concentrations promoted more apoptotic vSMCs, ox-LDL at lower concentrations triggered proliferation of vSMCs, and at higher concentrations induced apoptosis in vSMCs, ox-LDL played a promotional role in the pathogenesis and development of atherosclerosis by affecting vSMC proliferation and apoptosis.

Anti-oxidized low-density lipoprotein antibodies in chronic heart failure

Oxidative stress may play a significant role in the pathogenesis of heart failure(HF).Antibodies to oxidized low-density lipoprotein(oxLDL Abs) reflect an immune response to LDL over a prolonged period and may represent long-term oxidative stress in HF.The oxLDL plasma level is a useful predictor of mortality in HF patients,and measurement of the oxLDL Abs level may allow better management of those patients.Antibodies to oxLDL also significantly correlate with the New York Heart Association score.Hypercholesterolemia,smoking,hypertension,and obesity are risk factors for atherosclerotic coronary heart disease(CHD) leading to HF,but these factors account for only onehalf of all cases,and understanding of the pathologic process underlying HF remains incomplete.Nutrients with antioxidant properties can reduce the susceptibility of LDL to oxidation.Antioxidant therapy may be an adjunct to lipid-lowering,angiotensin converting enzyme inhibition and metformin(in diabetes) therapy for the greatest impact on CHD and HF.Observational data suggest a protective effect of antioxidant supple-mentation on the incidence of HD.This review summarizes the data on oxLDL Abs as a predictor of morbidity and mortality in HF patients.

Effects of Oxidized Low Density Lipoprotein on Transformation of Valvular Myofibroblasts to Osteoblast-like Phenotype

In order to investigate the roles of Wnt signal pathway in transformation of cardiac valvular myofibroblasts to the osteoblast-like phenotype, the primary cultured porcine aortic valve myofibroblasts were incubated with oxidized low density lipoprotein（ox-LDL, 50 mg/L）, and divided into four groups according to the ox-LDL treatment time： control group, ox-LDL 24-h group, ox-LDL 48-h group, and ox-LDL 72-h group. Wnt signal pathway blocker Dickkopf-1（DDK-1, 100 μg/L） was added in ox-LDL 72-h group. The expression of α-smooth muscle actin（α-SMA）, bone morphogenetic protein 2（BMP2）, alkaline phosphatase（ALP）, and osteogenic transcription factor Cbfa-1 was detected by Western blotting, and that of β-catenin, a key mediator of Wnt signal pathway by immunocytochemical staining method. The Wnt/β-catenin was observed and the transformation of myofibroblasts to the osteoblast-like phenotype was examined. The expression of α-SMA, BMP2, ALP and Cbfa-1 proteins in the control group was weaker than in the ox-LDL-treated groups. In ox-LDL-treated groups, the protein expression of α-SMA, BMP2, ALP, and Cbfa-1 was significantly increased in a time-dependent manner as compared with the control group, and there was significant difference among the three ox-LDL-treated groups（P〈0.05 for all）; β-catenin protein was also up-regulated in the ox-LDL-treated groups in a time-dependent manner as compared with the control group（P〈0.05）, and its transfer from cytoplasm to nucleus and accumulation in the nucleus were increased in the same fashion（P〈0.05）. After addition of DKK-1, the expression of α-SMA, bone-related proteins and β-catenin protein was significantly reduced as compared with ox-LDL 72-h group（P〈0.05）. The Wnt/ β-catenin signaling pathway may play an important role in transformation of valvular myofibroblasts to the osteoblast-like phenotype.

Oxidized low-density lipoprotein receptor 1:a novel potential therapeutic target for intracerebral hemorrhage

Oxidized low-density lipoprotein receptor 1(OLR1)is upregulated in neurons and participates in hypertension-induced neuronal apoptosis.OLR1 deletion exerts protective effects on cerebral damage induced by hypertensive-induced stroke.Therefore,OLR1 is likely involved in the progress of intracerebral hemorrhage.In this study,we examined the potential role of OLR1 in intracerebral hemorrhage using a rat model.OLR1 small interfering RNA(10μL;50 pmol/μL)was injected into the right basal ganglia to knock down OLR1.Twenty-four hours later,0.5 U collagenase type VII was injected to induce intracerebral hemorrhage.We found that knockdown of OLR1 attenuated neurological behavior impairment in rats with intracerebral hemorrhage and reduced hematoma,neuron loss,inflammatory reaction,and oxidative stress in rat brain tissue.We also found that silencing of OLR1 suppressed ferroptosis induced by intracerebral hemorrhage and the p38 signaling pathway.Therefore,silencing OLR1 exhibits protective effects against secondary injury of intracerebral hemorrhage.These findings suggest that OLR1 may be a novel potential therapeutic target for intracerebral hemorrhage.

Oxidized phospholipids and lipoprotein-associated phospholipase A_2 as important determinants of Lp(a) functionality and pathophysiological role

Lipoprotein（a） [Lp（a）] is composed of a low density lipoprotein（LDL）-like particle to which apolipoprotein（a）[apo（a）] is linked by a single disulfide bridge. Lp（a） is considered a causal risk factor for ischemic cardiovascular disease（CVD） and calcific aortic valve stenosis（CAVS）. The evidence for a causal role of Lp（a） in CVD and CAVS is based on data from large epidemiological databases, mendelian randomization studies, and genome-wide association studies. Despite the well-established role of Lp（a） as a causal risk factor for CVD and CAVS, the underlying mechanisms are not well understood. A key role in the Lp（a） functionality may be played by its oxidized phospholipids（OxPL） content. Importantly, most of circulating OxPL are associated with Lp（a）; however, the underlying mechanisms leading to this preferential sequestration of OxPL on Lp（a） over the other lipoproteins,are mostly unknown. Several studies support the hypothesis that the risk of Lp（a） is primarily driven by its OxPL content.An important role in Lp（a） functionality may be played by the lipoprotein-associated phospholipase A_2（Lp-PLA_2）,an enzyme that catalyzes the degradation of OxPL and is bound to plasma lipoproteins including Lp（a）. The present review article discusses new data on the pathophysiological role of Lp（a） and particularly focuses on the functional role of OxPL and Lp-PLA_2 associated with Lp（a）.

Expression of Monocyte Chemoattractant Protein-1 in Monocytes and Effects of Native and Oxidized Very Low Density Lipoproteins

Monocyte chemoattractant protein-1(MCP-1), a potent chemoattractant, is thought to play an important role in migration of monocytes into atherosclerotic lesions. The present study was designed to investigate the capacity of human peripheral blood monocytes to express MCP-1 and effects of native very low density lipoprotein (VLDL) and oxidized VLDL(OX-VLDL) on the expression. The total RNA was extracted from cultured monocytes, which were exposed to VLDL and OX-VLDL, and the media conditioned by monocytes were collected. MCP-1 mRNA expression was examined by Northern blot analysis. MCP-1 protein in conditioned media was determined by using sandwich ELISA. The results showed that monocytes can express MCP-1 after a 24 h incubation at 37℃，and the expression was markedly increased by a exposure to OX-VLDL, whereas the expression was slightly increased when exposed to VLDL. It suggests that the capacity of monocytes to produce MCP-1 that recruits and activates circulating monocytes may be of considerable importance in atherogenesis, and oxidation of VLDL enhances its potential to promote atherogenesis.

A modified laser-induced choroidal neovascularization animal model with intravitreal oxidized low-density lipoprotein

AIM: To investigate whether intravitreal injection of oxidized low-density lipoprotein(OxLDL) can promote laserinduced choroidal neovascularization(CNV) formation in mice and the mechanism involved, thereby to develop a better animal model.METHODS: C57BL6/J mice were randomized into three groups. Immediately after CNV induction with 532 nm laser photocoagulation, 1.0 μL of OxLDL [100 μg/m L in phosphate-buffered saline(PBS)] was intravitreally injected, whereas PBS and the same volume low-density lipoprotein(LDL;100 μg/m L in PBS) were injected into the vitreous as controls. Angiogenic and inflammatory cytokines were measured by quantitative real-time polymerase chain reaction(q RT-PCR) and Western blotting(WB) after 5 d, and CNV severity was analyzed by choroid flat mount and immunofluorescence staining after 1wk. In vitro, retinal pigment epithelial(RPE) cell line(ARPE19) were treated with OxLDL(LDL as control) for 8 h. Angiogenic and inflammatory cytokine levels were measured. A specific inhibitor of lectin-like oxidized low-density lipoprotein receptor 1(LOX1) was used to evaluate the role of LOX1 in this process.RESULTS: At 7 d after intravitreal injection of 1 μL(100 μg/mL) OxLDL, T15-labeled OxLDL was mainly deposited around the CNV area, and the F4/80-labeled macrophages, the CD31-labeled vascular endothelial cells number and CNV area were increased. Meanwhile, WB and qR T-PCR results showed that vascular endothelial growth factor(VEGF), CC chemokine receptor 2(CCR2), interleukin-6(IL-6), IL-1β, and matrix metalloproteinase 9(MMP9) expressions were increased, which was supported by in vitro experiments in RPE cells. LOX1 inhibitors significantly reduced expressions of inflammatory factors IL-1β and VEGF. CONCLUSION: A modified laser-induced CNV animal model is established with intravitreal injection of 1 μL(100 μg/mL) of OxLDL at 7 d, which at least partially through LOX1. This animal model can be used as a simple model for studying the role of OxLDL in age-related macular degeneration.

Obstructive jaundice leads to accumulation of oxidized low density lipoprotein in human liver tissue

Oxidized low density lipoprotein （ox-LDL） molecule is one of the most important modified lipoproteins produced during the oxidative stress. Modified lipoproteins have been defined as being part of the immune inflammatory mechanisms in association with oxidant stress. We have reported the accumulation of ox-LDL in Balb/c mice liver after bile duct ligation previously. Here, we investigated this finding in human beings with obstructive jaundice. Our study demonstrates that obstructive jaundice results in tremendous accumulation of ox-LDL in the liver tissue of patients.

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 （rmlL-4） were used to promote monocytes to differentiate and suppress lymphocytes. Then 50μg/mL oxHDL was added to stimulate BMDCs, using 50μg/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.

Oxidized low density lipoprotein (Ox-LDL) impacts on erythrocyte viscoelasticity and its molecular mechanism

Aim:The oxidized low-density lipoprotein(OxLDL) plays an important role in atherosclerosis yet it remains unclear if it damages circulating erythrocytes. Method: In this study。

Oxidized phospholipids modify plasminogen and apolipoprotein(a): Implications for vascular disease

Whereas the close structural homology between human plasminogen and apolipoprotein(a) has been known for a number of years only recent studies have revealed that both proteins carry linked oxidized phospholipids that may modify the function of these proteins. Future studies should provide a better understanding of oxidized phospholipid adducts and the role played by lipoprotein-associated phospholipase A2 for which cleavage specificity has been established when these modified lipids are in a free form.

Protein in oxidized low density lipoprotein may cause injury to mitochondria of mouse peritoneal macrophages

Injury to mitochondria of macrophages caused by oxidized low density lipoprotein (Ox-LDL) and the role of lipid hydroperoxides (LOOH). lipid and protein in Ox-LDL on the injury were studied by measuring mito-chondrial membrane potential (MMP) on ACAS570. The results showed that MMP decreased when macrophageswere treated by Ox-LDL. If LOOH in Ox-LDL was pre cleared by ebselen plus GSH. the decreased MMP could be recovered by about 20 %. Lipid moiety alone had no effect on IMP, but protein moiety could cause decrease ofMMP, the extent of the decrease was equivalent to that caused by Ox-LDL in which LOOH was pre-cleared by ebselen plus GSH.

Oxidized low-density lipoprotein stimulates CD206 positive macrophages upregulating CD44 and CD133 expression in colorectal cancer with high-fat diet

BACKGROUND Oxidized low-density lipoprotein(ox-LDL),which is abnormally increased in the serum of colorectal cancer(CRC)patients consuming a high-fat diet(HFD),may be one of the risk factors for the development of CRC.Ox-LDL exerts a regulatory effect on macrophages and may influence CRC through the tumor microenvironment.The role of ox-LDL in CRC remains unclear.AIM To investigate the role of ox-LDL through macrophages in HFD associated CRC.METHODS The expression of ox-LDL and CD206 was detected in colorectal tissues of CRC patients with hyperlipidemia and HFD-fed mice by immunofluorescence.We stimulated the macrophages with 20μg/mL ox-LDL and assessed the expression levels of CD206 and the cytokines by cell fluorescence and quantitative polymerase chain reaction.We further knocked down LOX-1,the surface receptor of ox-LDL,to confirm the function of ox-LDL in macrophages.Then,LoVo cells were co-cultured with the stimulated macrophages to analyze the CD44 and CD133 expression by western blot.RESULTS The expression of ox-LDL and the CD206 was significantly increased in the stroma of colorectal tissues of CRC patients with hyperlipidemia,and also upregulated in the HFD-fed mice.Moreover,an increased level of CD206 and decreased level of inducible nitric oxide synthase were observed in macrophages after ox-LDL continuous stimulation.Such effects were inhibited when the surface receptor LOX-1 was knocked down in macrophages.Ox-LDL could induce CD206+macrophages,which resulted in high expression of CD44 and CD133 in co-cultured LoVo cells.CONCLUSION Ox-LDL stimulates CD206+macrophages to upregulate CD44 and CD133 expression in HFD related CRC.

Inhibitory Effect of Isorhapontigenin on Copper-Mediated Peroxidation of Human Low-Density Lipoprotein in vitro

Aim To study the effect of Isorhapontigenin (Iso) on copper-mediatedperoxidation of human low-density lipoprotein (LDL) and on the toxicity of oxidized LDL (ox-LDL) tomouse macrophages in vitro. Methods Human LDL from sera df normal lipidemic donors was separated bysequential ultracentrifugation. The separated human IDL 1 mg·mL^(-1) in phosphate buffer saline, pH7.4, was incubated with cupric sulfate (10 μmol·L^(-1) ) at 37℃ for 10 h in the presence orabsence of various concentrations of Iso. Malondialdehyde (MDA) formation, vitamin E consumption,electrophoretic mobility of LDL, mitochondria] membrane potential of mouse peritoneal macrophages,phagocytosis of neutral red, and release of nitric oxide (NO) from macrophages were determined byvarious methods. Results Iso 1 - 100 μmol·L^(-1) significantly inhibited the increase of MDAformation, vitamin E consumption and electrophoretic mobility of LDL induced by Cu^(2+) in aconcentration-dependent manner. The injury of the mitochondrial membrane potential of mouseperitoneal macrophages due to incubation with ox-LDL (0.1 mg·mL^(-1)) at 37℃ for 12 h was markedlyprotected by 10 μmol·L^(-1) Iso. After pretreat-ment of the macrophages with 10 μmol · L^(-1)of Iso and then exposure to ox-LDL for 4 h, the reduction of phagocytosis of neutral red and releaseof NO in response to lipopolysaccharide (IPS) stimulation were significantly prevented. ConclusionIso has protective action against Cu^(2+) - mediated LDL peroxidation and ox-LDL induced toxicity tomacrophages in vitro.

Mitofusin2 Decreases Intracellular Cholesterol of Oxidized LDL-Induced Foam Cells from Rat Vascular Smooth Muscle Cells

Mitofusin2 （Mfn2） plays a pivotal role in the proliferation and apoptosis of vascular smooth muscle cells （VSMCs）. The purpose of this study was to investigate the effects of Mfn2 on the traffick- ing of intracellular cholesterol in the foam ceils derived from rat VSMCs （rVSMCs） and also to investigate the effects of Mfn2 on the expression of adenosine triphosphate-binding cassette subfamily A member 1 （ABCA1）, adenosine triphosphate-binding cassette subfamily G member 1 （ABCG1） and peroxisome proliferator-activated receptor gamma （PPARy）. The rVSMCs were co-cultured with oxi- dized low density lipoprotein （LDL, 80 ~tg/mL） to produce foam cells and cholesterol accumulation in cells. Before oxidized LDL treatment, different titers （20, 40 and 60 pfu/cell） of recombinant adenovirus containing Mfn2 gene （Adv-Mfn2） were added into the culture medium for 24 h to transfect the Mfn2 gene into the rVSMCs. Then the cells were harvested for analyses. The protein expression of Mfn2 was significantly higher in Adv-Mfn2-transfected group than in untransfected group （P〈0.05）, and the ex- pression levels significantly increased when the titer of Adv-Mfn2 increased （P〈0.05）. At 24 or 48 h af- ter oxidized LDL treatment, rVSMCs became irregular and their nuclei became larger, and their plasma abounded with red lipid droplets. However, the number of red lipid droplets was significantly decreased in Adv-Mfn2-transfected group as compared with untransfected group. At 48 h after oxidized LDL treatment, the intracellular cholesterol in rVSMCs was significantly increased （P〈0.05）, but it was sig- nificantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）, and it also significantly decreased when the titer of Adv-Mfn2 increased （P〈0.05）. The mRNA and pro- tein expression levels of ABCA1 and ABCG1 were significantly increased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. Though the mRNA and protein expression levels of PPARy was not significantly increased （P〉0.05）, the phosporylation levels of PPARy were signifi- cantly decreased in Adv-Mfn2-transfected group as compared with untransfected group （P〈0.05）. These results suggest that the transfection of Adv-Mfn2 can significantly reduce intracellular cholesterol in oxidized LDL-induced rVSMCs possibly by decreasing PPAR＇/phosporylation and then increasing pro- tein expression levels of ABCAI and ABCG1, which may be helpful to suppress the formation of foam cells.

EFFECT OF OXIDIZED-LDL ON NF-κB NUCLEAR TRANSLOCATION IN AORTIC SMOOTH MUSCLE CELLS ORIGINATED FROM RATS OF DIFFERENT AGES

Objective To investigate the molecular mechanism of atherosclerosis that related to age. Methods Immunohistochemistry staining and Western blot were adopted to determine the nuclear translocation of nuclear factor-kappa B (NF-κB) and expression of platelet-derived growth factor B (PDGF-B) in smooth muscle cells (SMCs) co-cultured with low density lipoprotein (LDL), oxidized LDL (ox-LDL), and ox-LDL+high density lipoprotein (HDL) originated from rats of 2 and 10 months old respectively. Fat stain was used to identify the lipid intake in SMCs. Results The optimal stimulation time of ox-LDL to SMCs was 12 hours. NF-κB intensity increased in most nuclei of SMCs that originated from rats of either 2 or 10 months old co-cultured with ox-LDL. The intensity of NF-κB and the amount of intracellular lipid taken in SMCs were more obvious in cells from 10-month-old rats than from the younger ones. Change of PDGF-B expression in SMCs was not remarkable in each group of rats. Conclusions The 10-month-old rats are more susceptive to ox-LDL than 2-month-old rats in activating nuclear transloca- tion of NF-κB. Maybe this is one of the important reasons contributing to the difference between the older and younger rats on the initiation and development of atherosclerosis lesion. Expression of PDGF-B is not associated with the activity of nuclear translocation of NF-κB.

EC,ASMC and Macrophage Oxidize Human Low Density Lipoprotein

To investigate the mechanism of LDL oxidation i n vivo , LDL was incubated with endothelium cell (EC),artery smooth muscle cel l (ASMC) and macrophage, and then the change of myeloperoxidase (MPO) activity i n cell and medium and the oxidation of LDL by those three cells were assessed. T he result showed that LDL promoted the activity of cellular and secretive myelop eroxidase which was concentration\|dependent on LDL; with elevation of MPO activ ity, oxidation of LDL intensified, which was expressed by the formation of conju gated dienes and the elevation of thiobarbituric acid teactive substance (TBARS ). Macrophage's MPO activity went up with the increase of LDL at both low and h igh concentration; EC's MPO activity went up with the increase of LDL only at h igh concentration and ASMC's MPO activity wasn't sensitive to LDL concentratio n change. The results suggest that Macrophage might be crucial to the oxidation of LDL in vivo , in which MPO might play an important role.

Inhibition of Oxidative Modification of Human Low Density Lipoprotein by Resveratrol

To further investigate whether resveratrol, a polyphenolic compound in red wine, affects the oxidation of human low density lipoprotein (LDL), LDL purified from normolipidemic subjects was subjected to Cu\+\{2+\}induced or azo compoundinitiated oxidative modification. The extent of LDL modification was assessed by measuring the formation of thiobarbituric acid reactive substances (TBARS) and the relative electrophoretic mobilities (REM) of LDL. Resveratrol (50 mol/L) reduced TBARS and REM of LDL during Cu\+\{2+\}induced oxidation by 70.5% and 42.3%, respectively (P<0.01), and prolonged the lag phase associated with the oxidative modification of LDL by copper ion or azo compound. These in vitro results suggest that resveratrol may afford LDL protection against oxidative modification, possibly by acting as a free radical scavenger.

Oxidative modification of high density lipoprotein induced by cultured human arterial smooth muscle cells

Objective: To observe the oxidative modification of high density lipoprotein (HDL) induced by cultured human arterial smooth muscle cells (SMCs). Methods: HDL cocultured with SMCs at 37℃ in 48 h was subjected, and native HDL (N-HDL) served as control. Oxidative modification of HDL was identified by using agarose gel electrophoresis. Absorbances of conjugated diene (CD) and lipid hydroperoxide (LOOH) were measured with ultraviolet spectrophotometry at 234 and 560 nm respectively, and fluorescence intensity of thiobarbuturic acid reaction substance (TBARS) with fluorescence spectrophotometry at 550 nm emission wavelength with excitation at 515 nm. Results: In comparison with N-HDL, the electrophoretic mobility of SMCs-cocultured HDL was increased, and the contents of CD, LOOH and TBARS HDL were very significantly higher than those of the control HDL (P<0.01). Conclusion: Oxidative modification of HDL can be induced by human arterial SMCs.