BACKGROUNDLipid abnormalities are often complicated by renal dysfunction. 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are the first-line choice for lowering cholesterol levels. The present study was designed to investigate whether statins could prevent and invert the development of renal injury in cholesterol-fed rabbits and to find the possible mechanism of their effects by detecting gene and protein expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in the renal artery.

METHODSTwenty-four male New Zealand white rabbits were divided into three groups: (1) control group, regular granules chow; (2) HC-diet group, granules chow with 1% cholesterol and 5% lard oil; and (3) fluvastatin group, 1% cholesterol and 5% lard oil diet plus fluvastatin [10 mg.kg(-1).d(-1)]. After 16 weeks, serum total cholesterol (TC), low-density lipoprotein (LDL) and creatinine (Cr) levels were measured. Renal hemodynamics and function, mainly including glomerular filtration rate (GFR) in vivo were quantified using (99m)Tc-DTPA single photon emission computed tomograph ((99m)Tc-DTPA SPECT). The thickness of the renal artery intima was quantitated in HE-stained segments by histomorphometry. Gene expression of LOX-1 in the renal artery was examined by semi-quantitative RT-PCR and its protein expression was evaluated by immunohistochemistry.

RESULTSHigh cholesterol diet induced hypercholesterolemia (HC) complicated by renal dysfunction with increased levels of serum lipid and Cr, decreased GFR and delayed excretion and extensively thickened renal arterial intima in the HC-diet group. Rabbits in the control group showed a minimal LOX-1 expression (mRNA and protein) in the endothelium and neointima of the renal artery. Intimal proliferation of the renal artery in the HC-diet group was associated with a marked increase of LOX-1 expression (protein and mRNA). Treatment with fluvastatin improved renal function, attenuated intimal proliferation of the renal artery and markedly decreased the enhanced LOX-1 expression in the endothelium and neointima of the renal artery in rabbits.

CONCLUSIONSFluvastatin treatment could prevent the development of renal injury in patients with HC and early atherosclerosis (AS). This beneficial effect might be mediated by its pleiotropic effects including a decrease in total cholesterol exposure level and prevention of LOX-1 expression in atherosclerotic arteries.

Animals ; Cholesterol ; blood ; Creatinine ; blood ; Fatty Acids, Monounsaturated ; pharmacology ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; pharmacology ; Hypercholesterolemia ; drug therapy ; metabolism ; pathology ; Immunohistochemistry ; Indoles ; pharmacology ; Kidney ; drug effects ; pathology ; Male ; RNA, Messenger ; analysis ; Rabbits ; Receptors, LDL ; analysis ; genetics ; Receptors, Oxidized LDL ; Scavenger Receptors, Class E ; Tomography, Emission-Computed, Single-Photon

OBJECTIVETo investigate the effects of oxidized low-density lipoprotein receptor 1 (LOX-1) on secretion of adhesive molecules mediated by ox-LDL in human umbilical endothelial cells (HUVECs).

METHODSHUVECs with different concentration of ox-LDL (0, 10, 20, 50, 100 microg/ml) were incubated for 24 h, or HUVECs were pretreated with 250 microg/ml poly (I) or 250 microg/ml carrageenan for 2 h and then incubated with 50 microg/ml ox-LDL for another 24 h. Expression of LOX-1 was determined by realtime RT-PCR and Western blot. mRNA and protein of ICAM-1, VCAM-1 and E-selectin were examined by RT-PCR and Western blot respectively.

RESULTSIncubation of HUVECs with ox-LDL (10-100 microg/ml) enhanced the expressions of LOX-1, ICAM-1 and E-selectin in a concentration-dependent manner (P < 0.01). On the contrary, ox-LDL did not affect the expression of VCAM-1 by HUVECs. The expression of LOX-1, ICAM-1 and E-selectin induced by ox-LDL were reduced in HUVECs pretreated with 250 microg/ml poly (I) or 250 microg/ml carrageenan for 2 h and then incubated with 50 microg/ml ox-LDL for 24 h. This showed that both poly (I) and carrageenan obviously decreased the expression of LOX-1, ICAM-1 and E-selectin induced by ox-LDL.

CONCLUSIONox-LDL may upregulate the expression of LOX-1, ICAM-1 and E-selectin, and LOX-1 blocker may partly inhibit this upregulation. The results suggest that the expression of inflammatory molecules induced by ox-LDL in HUVECs is mediated by LOX-1.

Cell Adhesion ; Cell Adhesion Molecules ; Cells, Cultured ; E-Selectin ; metabolism ; Endothelial Cells ; metabolism ; Endothelium, Vascular ; metabolism ; Humans ; Intercellular Adhesion Molecule-1 ; metabolism ; Lipoproteins, LDL ; biosynthesis ; RNA, Messenger ; metabolism ; Receptors, Oxidized LDL ; metabolism ; Scavenger Receptors, Class E ; metabolism ; Umbilical Veins ; cytology ; Vascular Cell Adhesion Molecule-1 ; metabolism

Oxidized low-density lipoprotein (ox-LDL)-induced macrophage foam cell formation and apoptosis play critical roles in the pathogenesis of atherosclerosis. Thioredoxin-1 (Trx) is an antioxidant that potently protects various cells from oxidative stress-induced cell death. However, the protective effect of Trx on ox-LDL-induced macrophage foam cell formation and apoptosis has not been studied. This study aims to investigate the effect of recombinant human Trx (rhTrx) on ox-LDL-stimulated RAW264.7 macrophages and elucidate the possible mechanisms. RhTrx significantly inhibited ox-LDL-induced cholesterol accumulation and apoptosis in RAW264.7 macrophages. RhTrx also suppressed the ox-LDL-induced overproduction of lectin-like oxidized LDL receptor (LOX-1), Bax and activated caspase-3, but it increased the expression of Bcl-2. In addition, rhTrx markedly inhibited the ox-LDL-induced production of intracellular reactive oxygen species (ROS) and phosphorylation of p38 mitogen-activated protein kinases (MAPK). Furthermore, anisomycin (a p38 MAPK activator) abolished the protective effect of rhTrx on ox-LDL-stimulated RAW264.7 cells, and SB203580 (a p38 MAPK inhibitor) exerted a similar effect as rhTrx. Collectively, these findings indicate that rhTrx suppresses ox-LDL-stimulated foam cell formation and macrophage apoptosis by inhibiting ROS generation, p38 MAPK activation and LOX-1 expression. Therefore, we propose that rhTrx has therapeutic potential in the prevention and treatment of atherosclerosis.
Anisomycin ; Apoptosis* ; Atherosclerosis ; Caspase 3 ; Cell Death ; Cholesterol ; Foam Cells* ; Humans* ; Lipoproteins ; Macrophages* ; p38 Mitogen-Activated Protein Kinases ; Phosphorylation ; Reactive Oxygen Species ; Receptors, Oxidized LDL ; Thioredoxins*

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) have recently been identified to be closely related to the occurrence and development of atherosclerosis (AS). A growing body of evidence has suggested Chinese medicine takes unique advantages in preventing and treating AS. In this review, the related research progress of AS and LOX-1 has been summarized. And the anti-AS effects of 10 active components of herbal medicine through LOX-1 regulation have been further reviewed. As a potential biomarker and target for intervention in AS, LOX-1 targeted therapy might provide a promising and novel approach to atherosclerotic prevention and treatment.
Humans ; Atherosclerosis ; Scavenger Receptors, Class E/physiology* ; Biomarkers ; Plant Extracts ; Lipoproteins, LDL

AIMTo develop a fluorescence polarization-based high throughput screening and identify ligands for human Lectin-like oxidized low-density lipoprotein receptor-1 (hLOX-1).

METHODSSequential ultracentrifugation at 4 degrees C from normolipidemic fasting volunteers to obtain low density lipoprotein (LDL), which was modified by CuSO4 (5 micromol x L(-1)) at 37 degrees C for 24 h. The assay was based on the interaction between receptor and ligand, and hLOX-1 was labeled by FITC and bound to its specific ligand, oxLDL. Different reaction time and DMSO concentration were optimized to determine the stability and tolerance of fluorescence polarization (FP) assay. 3 200 compounds were screened in black 384-well microplate by FP-based competitive displacement assay, at excitation filter of 485 nm and emission filter of 530 nm. Z' was used to assess the assay quality.

RESULTSThe FP-based HTS was formatted in a 384-well microplate with a Z' factor of 0. 75, and three active compounds for hLOX-1 were identified with IC50 below 40 micromol x L(-1) from total 3 200 compounds.

CONCLUSIONThe results indicated that the fluorescence polarization assay is stable, sensitive, reproducible and well suited for high throughput screening efforts.

Binding, Competitive ; Drug Evaluation, Preclinical ; methods ; Fluorescence Polarization ; methods ; Humans ; Ligands ; Lipoproteins, LDL ; metabolism ; Scavenger Receptors, Class E ; metabolism

OBJECTIVETo review the recent research progress in lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) including its protein, ligands, expression and pathophysiological significance. Data sources Information included in this article was identified by searching of PUBMED (1997 - 2006) online resources using the key term LOX-1.

STUDY SELECTIONMainly original milestone articles and critical reviews written by major pioneer investigators of the field were selected.

RESULTSThe key issues related to the LOX-1 protein as well as ligands for LOX-1. Factors regulating the expression of LOX-1 were summarized. The pathophysiological functions of LOX-1 in several diseases were discussed.

CONCLUSIONSIdentification of LOX-1 and a definition of its biological role in pathophysiologic states provide deeper insight into the pathogenesis of some cardiovascular diseases especially in atherosclerosis and provide a potential selective therapeutic approach. LOX-1 is unlocking and drugs targeting LOX-1 might be a promising direction to explore.

Animals ; Arthritis, Rheumatoid ; etiology ; Atherosclerosis ; etiology ; Humans ; Ligands ; Myocardial Infarction ; etiology ; Osteoarthritis ; etiology ; Scavenger Receptors, Class E ; chemistry ; genetics ; physiology

The aim of the study is to identify the effects and underlying mechanisms of visfatin on inflammation and necroptosis in vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were stimulated with visfatin or pretreated with Polyinosinic acid (LOX-1 inhibitor). By using the Western blot, RT-PCR, immunocytochemistry, enzyme-linked immunosorbent assay (ELISA), MTT and flow cytometry technique, the occurrence of inflammation and necroptosis in HUVECs were evaluated. Our results showed that 100 ng/mL visfatin significantly increased the mRNA and protein expression of monocyte chemotactic protein 1 (MCP-1) and LOX-1 after 24 hours' treatment in HUVECs. However, pretreatment with Polyinosinic acid could significantly reduce the expression of MCP-1 compared with visfatin group. Additionally, 100 ng/mL visfatin could induce the production of necrotic features and increase the mRNA expression of BMF (one of the markers of necroptosis), while pretreating with Polyinosinic acid markedly downregulated the mRNA expression of BMF gene and promoted the cell proliferation. These results indicate that visfatin might induce inflammation and necroptosis via LOX-1 in HUVECs, suggesting that visfatin plays a central role in the development of atherosclerosis.
Cells, Cultured ; Human Umbilical Vein Endothelial Cells ; Humans ; Inflammation/chemically induced* ; Necroptosis ; Nicotinamide Phosphoribosyltransferase ; Scavenger Receptors, Class E/genetics*

OBJECTIVETo explore action mechanism of electroacupuncture for coronary atherosclerotic heart disease (CHD) in order to provide experimental support for clinical acupoint selection.

METHODSAmong sixty clean-grade healthy male Wistar rats, twenty-four cases were randomly selected as a normal control group and an electroacupuncture (EA) preconditioning group, 12 cases in each one. Then rats in the EA preconditioning group and the rest 36 rats were fed with high fat diet for 12 weeks to duplicate the CHD model. When the models were successfully established, the rats were randomly divided into a model control group, an EA group and a medication group, 12 cases in each one. EA was applied with Hwa-to SDZ-IV apparatus in the EA preconditioning group at "Neiguan" (PC 6) and "Xinshu" (BL 15), 1 mA in current intensity, 2 Hz in frequency, 30 min per times, once every other day for 14 weeks. When model was established, the same acupoint and method was used in the EA group for 2 weeks while intragastric administration of atorvastatin mixed suspension, 0.25 mg/kg, once a day, was applied in the medication group for 2 weeks. The content of oxidized low-density lipoprotein (oxLDL) in the serum was tested by double antibody enzyme-linked immunosorbent assay (ELISA) while content of lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) in coronary arterial tissue was test by western blot method. Expression of LOX-1 mRNA was tested by fluorogenic quantitative polymerase chain reaction (PCR).

RESULTSAfter model was duplicated successfully, the content of oxLDL in the serum and the expression of LOX-1 and its mRNA in coronary arterial tissue in the model control group were increased significantly compared with those in the normal control group (all P < 0.01). Compared with the model control group, the content of oxLDL in the serum and the expression of LOX-1 and its mRNA in coronary arterial tissue in the EA preconditioning group, EA group and medication group were significantly reduced (all P < 0.01).

CONCLUSIONThe electroacupuncture at "Neiguan" (PC 6) and "Xinshu" (BL 15) could effectively reduce the content of oxLDL in the serum and expression of LOX-1 and its mRAN in coronary arterial tissue in CHD rats. The oxidative modificatory low-density lipoprotein and its specific receptor system could be one of the ways to prevention and treatment of acupuncture for CHD.

Animals ; Coronary Disease ; genetics ; metabolism ; therapy ; Disease Models, Animal ; Electroacupuncture ; Humans ; Lipoproteins, LDL ; genetics ; metabolism ; Male ; Rats ; Rats, Wistar ; Scavenger Receptors, Class E ; genetics ; metabolism

OBJECTIVETo study the changes of lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) expression in the autologous vein grafts and vein graft atherosclerotic lesions.

METHODSThirty New Zealand white rabbits were randomly assigned to normal control group (rabbits fed with normal diet, n = 10), vein graft group (autologous external jugular vein grafting to common carotid artery and fed with normal diet, n = 10) or vein graft plus high-lipid diet group (autologous vein graft and fed with high-lipid diet, n = 10) for 12 weeks. LOX-1 expressions in the grafts were examined by immunohistochemistry and semi-quantitative reverse transcription-PCR. The relationships between serum total cholesterol level, intimal thickness and LOX-1 expression were also investigated.

RESULTSLOX-1 expression was low in the endothelium of external jugular veins in the normal control group and significantly increased in the endothelium and neointima of vein grafts in the vein graft group (0.31 +/- 0.14 vs. 0.09 +/- 0.04, P < 0.01) and which was further increased in the endothelium and atherosclerotic lesions in the vein graft plus high-lipid diet group (0.93 +/- 0.34 vs. 0.31 +/- 0.14, P < 0.01). LOX-1 expression in the atherosclerotic lesions was located both in endothelial cells and foam cells and the expression was most prominent in endothelial cells. LOX-1 expression and intimal thickness were positively related to serum total cholesterol level (P = 0.00 and 0.02) and the partial correlation coefficient was 0.78 and 0.42, respectively.

CONCLUSIONSLOX-1 expression is increased in endothelium and neointima of autologous vein grafts of rabbits. Hypercholesterolemia upregulates LOX-1 expression in vein graft atherosclerosis. Thus, LOX-1 might play an important role in the pathogenesis of vein graft atherosclerosis.

Animals ; Atherosclerosis ; metabolism ; pathology ; Disease Models, Animal ; Graft Occlusion, Vascular ; metabolism ; pathology ; Lipoproteins, LDL ; blood ; Male ; Rabbits ; Scavenger Receptors, Class E ; metabolism ; Transplantation, Autologous ; Veins ; transplantation

OBJECTIVETo assess the value of serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) levels and LOX-1 mRNA expression in peripheral blood mononuclear cells in early diagnosis of acute coronary syndrome (ACS).

METHODSEnzyme-linked immunosorbent assay was used to detect the levels of plasma ox-LDL and LOX-1 in 95 patients with ACS, 60 with stable angina pectoris (SAP) and 40 normal control subjects. The expression of LOX-1 mRNA in peripheral blood mononuclear cells was detected by RT-PCR in the 3 groups.

RESULTSThe levels of ox-LDL, LOX-1 and LOX-1 mRNA in the peripheral blood mononuclear cells were significantly higher in ACS patients than in SAP patients and normal control subjects (P<0.05). In ACS group, the level of plasma ox-LDL was significantly correlated to serum LOX-1 and LOX-1 mRNA expression in peripheral mononuclear cells.

CONCLUSIONThe level of plasma soluble LOX-1 and LOX-1 mRNA in peripheral mononuclear cells are significantly increased in ACS, and when combined, they provide a useful means for detecting ACS in the prophase.

Acute Coronary Syndrome ; blood ; diagnosis ; Aged ; Early Diagnosis ; Female ; Humans ; Leukocytes, Mononuclear ; metabolism ; Male ; Middle Aged ; RNA, Messenger ; genetics ; Scavenger Receptors, Class E ; blood