Lipoprotein lipase (LPL) is known to be attached to the luminal surface of vascular endothelial cells in a complex with membrane-bound heparan sulfate, and released into blood stream by heparin. LPL that catalyzes hydrolysis of triglyceride (TGL) on chylomicron and VLDL into two fatty acids and monoacylglycerol, is also implicated to participate in an enhancement of cholesterol uptake by arterial endothelial cells in vitro. But little is known about the LPL-mediated cholesterol uptake in physiological state. In this study, changes in blood lipid composition and levels of lipoproteins were determined after the injection of heparin in human. The level of LPL in plasma was increased from 0 to 11 mU/ml within 30-40 min post-heparin administration and decreased to the basal level within 2 h. The level of TGL in plasma decreased from 70 mg/dl to 20 mg/dl within 1 h and gradually increased to 80 mg/dl within 4 h. However the level of total cholesterol in plasma remained at 140 mg/dl during an experimental period of 4 h. Analysis of Lipoproteins in plasma by NaBr density gradient ultracentrifugation showed that the level of VLDL decreased from 50 mg/dl to 10 mg/dl within 1-2 h and returned to normal plasm level at 4 h. However there were no significant changes in the level of LDL and HDL. These results suggest that, at least, in normo-lipidemic subjects, increased free plasm LPL acts primarily on VLDL and failed to show any significant uptake of cholesterol-rich lipoproteins in human.
Adult ; Cholesterol/blood ; Heparin/pharmacology* ; Heparin/administration & dosage ; Human ; Immunoblotting ; Lipoprotein Lipase/blood* ; Lipoproteins/blood* ; Lipoproteins, HDL/blood ; Lipoproteins, LDL/blood ; Lipoproteins, VLDL/blood ; Triglycerides/blood

OBJECTIVETo investigate neuroprotection of resveratrol against cytotoxicity of oxidized low density lipoprotein (oxLDL) in PC12 cells.

METHODSPC12 cells were pretreated with resveratrol for one hour as a neuron model and then exposed to oxLDL at varied concentrations. Effects of resveratrol on cell viability, permeability of cell membrane, cell nucleus and activity of caspase-3 were evaluated with MTT assay, lactic acid dehydrogenase (LDH) release assay, DNA fragmentation (TUNEL) assay and assay for caspase-3 activity (caspase assay).

RESULTSCell viability, LDH release rate, percentage of cells with positive TUNEL and activity of caspase-3 were (62 +/- 3)%, (23 +/- 3)%, (26 +/- 5)% and (0.811 +/- 0.049) mol.min(-1).microg(-1), vs (84 +/- 7)%, (13 +/- 4)%, (12 +/- 4)% and (0.553 +/- 0.048) mol.min(-1).microg(-1) in PC12 cells treated with 10 mg/L oxLDL vs in those treated with 10 mg/L oxLDL plus 50 micromol/L resveratrol, respectively, with statistically significant difference.

CONCLUSIONResveratrol could attenuate cytotoxicity induced by oxLDL in PC12 cells with neuroprotection.

Animals ; Cell Survival ; drug effects ; Lipoproteins, LDL ; toxicity ; Neuroprotective Agents ; pharmacology ; PC12 Cells ; Rats ; Stilbenes ; pharmacology

Effect of antiatherogenic high density lipoprotein (HDL) and apolipoprotein AI (apoAI) on production of prostaglandin E2 (PGE2) by human monocyte-derived macrophages was investigated. Macrophages were loaded with acetylated low density lipoprotein followed by incubation with HDL3 or apoAI. PGE2 produced and secreted in culture supernatant was quantified by enzyme immunoassay. HDL3 induced production of PGE2 by macrophages in a time-dependent manner. 24 h after incubation, PGE2 production by HDL3-treated macrophages increased 3.7-fold of that by control cells. ApoAI also induced PGE2 secretion to 2.1-fold, which was significantly less than HDL3. The data indicate that both HDL3 and lipid-free apoAI enhance PGE2 synthesis and secretion by human macrophages and this may further contribute to the protection from atherosclerosis.
Apolipoprotein A-I ; pharmacology ; Arteriosclerosis ; prevention & control ; Culture Media, Conditioned ; Dinoprostone ; biosynthesis ; Humans ; Lipoproteins, HDL ; pharmacology ; Lipoproteins, HDL3 ; Macrophages ; cytology ; metabolism ; Monocytes ; metabolism

Tissue factor pathway inhibitor (TFPI) is one of the major physiological inhibitors of the human blood coagulation cascade and may have great potential in the prevention and therapy of diseases caused by thrombus formation. In this study, recombinant human tissue factor was generated in E. coli containing a recombinant vector constructed by inserting TFPI cDNA into pGEX-2T vector. The generated recombinant TFPI (rTFPI) could be simply purified with glutathione-agarose affinity method and maintained its biological function in terms of inhibition of tissue factor and factor Xa.
Escherichia coli ; genetics ; metabolism ; Humans ; Lipoproteins ; biosynthesis ; genetics ; pharmacology ; Peptide Fragments ; biosynthesis ; genetics ; pharmacology ; Plasmids ; Recombinant Proteins ; biosynthesis ; pharmacology ; Transfection

The preparation of a novel amphiphilic dietary fiber LDL adsorbent with sulfonic group and laurylamine group was studied. The effects of reaction time and reaction temperature on the adsorption rate were studied. The results show that the adsorption rates for the removal of Total cholesterol (TC), Low-density lipoprotein cholesterol (LDL-C) and High-density lipoprotein cholesterol (HDL-C) are 40.8%, 50.8% and 23.6%, respectively. The amphiphilic adsorbent has better selectivity in removing LDL-C.
Adsorption ; Binding, Competitive ; Cholesterol ; blood ; isolation & purification ; Dietary Fiber ; pharmacology ; Lipoproteins, LDL ; blood ; isolation & purification

OBJECTIVETo explore the effect of Xinfeng Capsule (XC) on lipoprotein metabolism of rheumatoid arthritis (RA) patients.

METHODSTotally 180 RA patients were assigned to the experimental group and the control group by random digit table, 90 in each group. Patients in the experimental group took XC (three pills each time, three times daily), while those in the control group took Methotrexate Tablet (four tablets each time, once per week). One month consisted of one therapeutic course and all patients were treated for two therapeutic courses. A healthy control group consisting of 60 patients was also set up. Changes of lipoprotein indices, clinical efficacy, lipid metabolism, joint symptoms and signs, activity indicators were observed, and correlation analyses were performed.

RESULTSCompared with the healthy control group, expression levels of prealbumin (PA), globulin (GLO), high-density lipoprotein (HDL), apolipoprotein Al (Apo-A1) were lowered in RA patients (P <0. 05, P <0. 01). Correlation analyses showed that PA was negatively correlated with joint tenderness, morning stiffness time, disease activity score (DAS-28), C-reactive protein (CRP), interleukin (IL)-6, respectively. Total protein (TP) was negatively correlated with joint tenderness. GLO was negatively correlated with joint tenderness and DAS-28. HDL was negatively correlated with erythrocyte sedimentation rate (ESR) and endothelin (ET)-1. Apo-Al was negatively correlated with joint pain; Apo-B was negatively correlated with CRP; LDL was negatively correlated with morning stiffness time (P <0. 05, P <0. 01). Compared with before treatment, expression levels of PA, HDL, Apo-A1 , Apo-B, and serum IL-10 contents increased, and expression levels of ESR, CRP, IL-6, ET-1 , joint pain, joint swelling, morning stiffness time, and DAS-28 decreased in the experimental group (P <0. 05, P <0. 01). PA increased more after treatment than before treatment in the control group (P <0. 01). There was statistical difference in joint symptoms (except joint tenderness) and activity indices (except ET-1) in the control group (P <0. 05, P <0. 01). Compared with the control group after treatment, PA and HDL increased, ET-1 and duration of morning stiffness decreased in the experimental group (all P <0. 05).

CONCLUSIONSLipoprotein metabolic disorder exists in RA patients, and it is associated with disease activity. XC could obviously improve lipoprotein metabolism and joint symptoms.

Arthritis, Rheumatoid ; drug therapy ; metabolism ; Blood Sedimentation ; C-Reactive Protein ; Capsules ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Humans ; Interleukin-10 ; Interleukin-6 ; Lipoproteins ; Lipoproteins, HDL ; metabolism ; Methotrexate

Animals ; Arteriosclerosis ; drug therapy ; Cholesterol, LDL ; blood ; Drugs, Chinese Herbal ; pharmacology ; Hyperlipidemias ; drug therapy ; Lipids ; blood ; Lipoproteins ; blood ; Lipoproteins, LDL ; blood ; Male ; Rabbits ; Tablets ; Triglycerides ; blood

To observe the effect of oxidized low density lipoprotein (OxLDL) on arterial endothelial cells apoptosis in vivo, we established a model in which Sprague-Dawley rats were given intraperitoneal and intravenous injection of unmodified LDL (8 mg/kg every day) via the tail vein. Seven days after the injection, the aortic endothelial cells specimens were prepared by an en face preparation of rat aorta. The apoptotic cells were identified and counted by in situ nick and labelling (TUNEL) method and light microscopy. The numbers of the apoptotic cells were 12.52 +/- 4.71/field in the intraperitoneal injection control group, 11.41 +/- 2.94/field in the intravenous injection control group, 22.98 +/- 8.01/field in the intraperitoneal injection LDL group and 103.8 +/- 11.5/field in the intravenous injection LDL group, respectively. The difference was significant between injection LDL group and control (P < 0.01), and the difference was also significant between two LDL injection groups (P < 0.01). These findings suggest that injection of LDL can induce apoptosis in arterial endothelial cells and the effect is especially significant with intravenous injection LDL. After injection, oxidative modification of LDL may occur in local arteries and causes injury to the endothelial cells.
Aorta ; Apoptosis/*drug effects ; Endothelium, Vascular/*pathology ; In Situ Nick-End Labeling ; Injections, Intraperitoneal ; Injections, Intravenous ; Lipoproteins, LDL/*metabolism ; Lipoproteins, LDL/*pharmacology ; Oxidation-Reduction ; Random Allocation ; Rats, Sprague-Dawley

The purpose of the present study was to investigate the effect of pravastatin on cholesteryl esters in foam cells of murine macrophages and the relation with caveolin-1. RAW 264.7 murine macrophages were coincubated with 80 mg/L oxidized low density lipoprotein (ox-LDL) and pravastatin (0~100 mumol/L) respectively for 24 h. When the best control concentration of pravastatin was confirmed, RAW 264.7 murine macrophages were coincubated with 80 mg/L ox-LDL and pravastatin of the best concentration respectively for 0, 6, 12, 24 h. Oil red O dyeing experiment was used to show the lipid droplets in foam cells. High performance liquid chromatography (HPLC) analysis was performed to determine the content of cellular cholesterol. The level of caveolin-1 was determined by Western blot analysis. The result showed that when macrophages were incubated with 80 mg/L ox-LDL, the ratio of cellular cholesteryl ester to total cholesterol (CE/TC) was beyond 50% through HPLC analysis, and a great deal of lipid droplets displayed in cells through Oil red O dyeing experiment, which manifested the formation of the foam cells. Pravastatin could decrease CE in foam cells in a concentration-dependent manner (1~100 mumol/L). At the concentration of 100 mumol/L, pravastatin decreased cellular CE more than 50%. The effects of pravastatin on the decrease of CE in murine macrophages also displayed a time-dependent manner (incubated with 100 mumol/L pravastatin from 6 to 24 h). Moreover, the expression of caveolin-1 was decreased when the macrophages were incubated with ox-LDL (80 mg/L), while treatment with pravastatin increased the level of caveolin-1 and displayed a concentration- and time-dependent manner. These results suggest that pravastatin could inhibit the development of foam cells through the decrease of cellular CE, which may be related to the upregulation of caveolin-1.
Animals ; Anticholesteremic Agents ; pharmacology ; Caveolin 1 ; metabolism ; Cell Line ; Cells, Cultured ; Cholesterol Esters ; metabolism ; Foam Cells ; metabolism ; Lipoproteins, LDL ; pharmacology ; Macrophages ; cytology ; Pravastatin ; pharmacology ; Rats

BackgroundOxidized low-density lipoprotein (ox-LDL)-induced oxidative stress and endothelial apoptosis are essential for atherosclerosis. Our previous study has shown that ox-LDL-induced apoptosis is mediated by the protein kinase RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic translation initiation factor 2α-subunit (eIF2α)/CCAAT/enhancer-binding protein homologous protein (CHOP) endoplasmic reticulum (ER) stress pathway in endothelial cells. Statins are cholesterol-lowering drugs that exert pleiotropic effects including suppression of oxidative stress. This study aimed to explore the roles of simvastatin on ox-LDL-induced ER stress and apoptosis in endothelial cells.

MethodsHuman umbilical vein endothelial cells (HUVECs) were treated with simvastatin (0.1, 0.5, or 2.5 μmol/L) or DEVD-CHO (selective inhibitor of caspase-3, 100 μmol/L) for 1 h before the addition of ox-LDL (100 μg/ml) and then incubated for 24 h, and untreated cells were used as a control group. Apoptosis, expression of PERK, phosphorylation of eIF2α, CHOP mRNA level, and caspase-3 activity were measured. Comparisons among multiple groups were performed with one-way analysis of variance (ANOVA) followed by post hoc pairwise comparisons using Tukey's tests. A value of P < 0.05 was considered statistically significant.

ResultsExposure of HUVECs to ox-LDL resulted in a significant increase in apoptosis (31.9% vs. 4.9%, P < 0.05). Simvastatin (0.1, 0.5, and 2.5 μmol/L) led to a suppression of ox-LDL-induced apoptosis (28.0%, 24.7%, and 13.8%, F = 15.039, all P < 0.05, compared with control group). Ox-LDL significantly increased the expression of PERK (499.5%, P < 0.05) and phosphorylation of eIF2α (451.6%, P < 0.05), if both of which in the control groups were considered as 100%. Simvastatin treatment (0.1, 0.5, and 2.5 μmol/L) blunted ox-LDL-induced expression of PERK (407.8%, 339.1%, and 187.5%, F = 10.121, all P < 0.05, compared with control group) and phosphorylation of eIF2α (407.8%, 339.1%, 187.5%, F = 11.430, all P < 0.05, compared with control group). In contrast, DEVD-CHO treatment had no significant effect on ox-LDL-induced expression of PERK (486.4%) and phosphorylation of eIF2α (418.8%). Exposure of HUVECs to ox-LDL also markedly induced caspase-3 activity together with increased CHOP mRNA level; these effects were inhibited by simvastatin treatment.

ConclusionsThis study suggested that simvastatin could inhibit ox-LDL-induced ER stress and apoptosis in vascular endothelial cells.

Apoptosis ; drug effects ; Cells, Cultured ; Endoplasmic Reticulum Stress ; drug effects ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Lipoproteins, LDL ; pharmacology ; Oligopeptides ; pharmacology ; Simvastatin ; pharmacology