Effect of high glucose concentrations on expression of ELAM-1, VCAM-1 and ICAM-1 in HUVEC with and without cytokine activation

Diabetes mellitus is associated with an increased prevalence of endothelial dysfunction and development of atherosclerotic vascular diseases. We demonstrate here that hyperglycemia results in the expression of adhesion molecules on endothelial cells in vitro. Incubation of human umbilical vein endothelial cells (HUVEC) in a culture medium with 11.0 mM, 16.5 mM and 22.0 mM glucose concentrations induced the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and endothelial-leukocyte adhesion molecule-1 (ELAM-1). This effect was detectable after 24 h incubation of HUVEC with a high glucose concentration. The effect of high glucose concentration on TNF-alpha induced expression of ELAM-1, VCAM-1 and ICAM-1 was negligible, if at all. These results show that even a short-term exposure of endothelial cells (ECs) to high glucose concentration leads to their activation associated with increased expression of adhesion molecules such as ELAM-1, VCAM-1 and ICAM-1.     

Elevated AGE-modified ApoB in sera of euglycemic, normolipidemic patients with atherosclerosis: relationship to tissue AGEs.

BACKGROUND: Advanced glycation endproducts (AGEs) are implicated in the pathogenesis of atherosclerotic vascular disease of diabetic and nondiabetic etiology. Recent research suggests that advanced glycation of ApoB contributes to the development of hyperlipidemia. AGE-specific receptors, expressed on vascular endothelium and mononuclear cells, may be involved in both the clearance of, and the inflammatory responses to AGEs. The aim of this study was to examine whether there is a relationship between serum AGE-ApoB and AGEs in arterial tissue of older normolipidemic nondiabetic patients with occlusive atherosclerotic disease, compared with age-matched and younger asymptomatic persons. MATERIALS AND METHODS: Serum AGE-ApoB was measured by ELISA in 21 cardiac bypass patients. Furthermore, an AGE-specific monoclonal antibody, and polyclonal antibodies against anti-AGE-receptor (anti-AGE-R) 1 and 2 were used to explore the localization and distribution of AGEs and AGE-R immunoreactivity (IR) in arterial segments excised from these patients. RESULTS: Serum AGE-ApoB levels were significantly elevated in the asymptomatic, older population, compared with those in young healthy persons (259 +/- 24 versus 180 +/- 21 AGE U/mg of ApoB, p < 0.01). Higher AGE-ApoB levels were observed in those patients with atherosclerosis (329 +/- 23 versus 259 +/- 24 AGE U/mg ApoB, p < 0.05). Comparisons of tissue AGE-collagen with serum AGE-ApoB levels showed a significant correlation (r = 0.707, p < 0.01). In early lesions, AGE-IR occurred mostly extracellularly. In fatty streaks and dense, cellular atheromatous lesions, AGE-IR was visible within lipid-containing smooth muscle cells and macrophages, while in late-stage, acellular plaques, AGE-IR occurred mostly extracellularly. AGE-R1 and -R2 were observed on vascular endothelial and smooth-muscle cells and on infiltrating mononuclear cells in the early-stage lesions, whereas in dense, late-stage plaques, they colocalized mostly with lipid-laden macrophages. On tissue sections, scoring of AGE-immunofluorescence correlated with tissue AGE and plasma AGE-ApoB. CONCLUSIONS: (1) The correlation between arterial tissue AGEs and circulating AGE-ApoB suggests a causal link between AGE modification of lipoproteins and atherosclerosis. AGE-specific receptors may contribute to this process. (2) Serum AGE-ApoB may serve to predict atherosclerosis in asymptomatic patients.     

The proglycation effect of caffeic acid leads to the elevation of oxidative stress and inflammation in monocytes, macrophages and vascular endothelial cells

In this study, the effects of phenolic acids [caffeic acid (CA), ferulic acid, m-coumaric acid, and chlorogenic acid] on methylglyoxal (MG)-induced protein glycation were investigated in vitro. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and advanced glycation end products (AGEs)-specific fluorescence showed that MG-mediated protein modification was enhanced dose-dependently by CA (P<.05), whereas α-lipoic acid, glutathione and EDTA inhibited these changes. Electron paramagnetic resonance spectra showed that CA increased reactive oxygen species (ROS) production during glycation, suggesting the proglycation mechanism of CA is associated with its pro-oxidative properties. Additionally, fetal bovine serum (FBS) was utilized as the source of target proteins for evaluating the effects of CA in cells. Differential glycation of FBS samples was performed by incubating FBS with MG, CA or aminoguanidine (AG, an AGE inhibitor). FBS incubated with MG and CA (MG/CA-FBS) evoked the greatest deleterious responses, as follows: (1) inducing proinflammatory tumor necrosis factor (TNF)-α and interleukin-1β expression and ROS production in monocytic THP-1 cells, (2) stimulating TNF-α secretion in RAW 264.7 macrophages and (3) causing oxidative DNA damage and inducing the expression of receptor for AGEs (RAGE), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 in human umbilical vein endothelial cells. Furthermore, adhesion and transendothelial migration of monocytes were also significantly increased by MG/CA-FBS treatment compared to MG-FBS (P<.05). In conclusion, our data show that CA exhibits pro-oxidative and pro-glycative effects during the glycation process, suggesting a detrimental role for CA under high-glycotoxin conditions.     

Effects of TNF-alpha on leukocyte adhesion molecule expressions in cultured human lymphatic endothelium.

TNF-alpha alters leukocyte adhesion molecule expression of cultured endothelial cells like human umbilical vein endothelial cells (HUVEC). This study was designed to investigate the changes in vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and platelet endothelial cell adhesion molecule-1 (PECAM-1) expression with TNF-alpha stimulation in cultured human neonatal dermal lymphatic endothelial cells (HNDLEC). The real-time quantitative PCR analysis on HNDLEC showed that TNF-alpha treatment leads to increases of VCAM-1 and ICAM-1 mRNAs to the 10.8- and 48.2-fold levels of untreated cells and leads to a reduction of PECAM-1 mRNA to the 0.42-fold level of untreated cells. Western blot and immunohistochemical analysis showed that TNF-alpha leads to VCAM-1 and ICAM-1 expressions that were inhibited by antiserum to human TNF receptor or by AP-1 inhibitor nobiletin. In flow cytometry analysis, the number of VCAM-1- and ICAM-1-positive cells increased, and PECAM-1-positive cells decreased with TNF-alpha treatment. Regarding protein amounts produced in cells and amounts expressed on the cell surface, VCAM-1 and ICAM-1 increased in HNDLEC and HUVEC, and PECAM-1 decreased in HNDLEC in a TNF-alpha concentration-dependent manner. VCAM-1, ICAM-1, and PECAM-1 protein amounts in TNF-alpha-stimulated cells were lower in HNDLEC than in HUVEC. This suggests that the lymphatic endothelium has the TNF-alpha-induced signaling pathway, resulting in increased VCAM-1 and ICAM-1 expression to a weaker extent than blood endothelium and PECAM-1 reduction to a stronger extent than blood endothelium.     

Gene expression of LOX-1, VCAM-1, and ICAM-1 in pre-atherosclerotic mice

To identify markers of the earliest stage of atherosclerosis, endothelial dysfunction, we evaluated the gene expression of lectin-like oxidized-low-density-lipoprotein receptor-1 (LOX-1), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in very young pre-atherosclerotic mice. Furthermore, the plasma levels of the soluble VCAM-1 and ICAM-1 were compared to the gene expression profiles. Gene expressions of LOX-1 and VCAM-1 were up-regulated in young apoE^−/− mice, and thus, it seems probable that these genes play a role in pre-atherosclerosis. Contrarily, the gene expression profile of ICAM-1 did not show any apparent differences between the groups, questioning the involvement of this molecule in the early development of atherosclerosis. Plasma levels of sVCAM-1 and sICAM-1 were similar in all mice and did not correlate with the vascular gene expression of the corresponding genes. It therefore seems likely that these circulating markers are not suited to detect early atherosclerosis.     

ESM-1 promotes adhesion between monocytes and endothelial cells under intermittent hypoxia

Intermittent hypoxia (IH), the key property of obstructive sleep apnea (OSA), is closely associated with endothelial dysfunction. Endothelial-cell-specific molecule-1 (ESM-1, Endocan) is a novel, reported molecule linked to endothelial dysfunction. The aim of this study is to evaluate the effect of IH on ESM-1 expression and the role of ESM-1 in endothelial dysfunction. We found that serum concentration of ESM-1, inter-cellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) is significantly higher in patients with OSA than healthy volunteers (p < 0.01). The expression of ESM-1, hypoxia-inducible factor-1 alpha (HIF-1α), and vascular endothelial growth factor (VEGF) was significantly increased in human umbilical vein endothelial cells (HUVECs) by treated IH in a time-dependent manner. HIF-1α short hairpin RNA and vascular endothelial growth factor receptor (VEGFR) inhibitor inhibited the expression of ESM-1 in HUVECs. ICAM-1 and VCAM-1 expressions were significantly enhanced under IH status, accompanied by increased monocyte–endothelial cell adhesion rate ( p < 0.001). Accordingly, ESM-1 silencing decreased the expression of ICAM-1 and VCAM-1 in HUVECs, whereas ESM-1 treatment significantly enhanced ICAM-1 expression accompanied by increasing adhesion ability. ESM-1 is significantly upregulated by the HIF-1α/VEGF pathway under IH in endothelial cells, playing a critical role in enhancing adhesion between monocytes and endothelial cells, which might be a potential target for IH-induced endothelial dysfunction.     

ICAM-1 and VCAM-1 mediate endotoxemic myocardial dysfunction independent of neutrophil accumulation

Both intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) have been implicated in neutrophil-mediated lung and liver injury during sepsis. However, the role of these adhesion molecules as well as the contribution of neutrophils in myocardial dysfunction during sepsis remains to be determined. The purpose of this study was to examine the role of ICAM-1, VCAM-1, and neutrophils in lipopolysaccharide (LPS)-induced myocardial dysfunction. Mice were subjected to LPS (0.5 mg/kg ip) or vehicle (normal saline), and left ventricular developed pressure (LVDP) was determined by the Langendorff technique. LVDP was depressed by nearly 40% at 6 h after LPS. Immunofluorescent staining revealed a temporal increase in myocardial ICAM-1/VCAM-1 expression and neutrophils after LPS. Antibody blockade of VCAM-1 reduced myocardial neutrophil accumulation and abrogated LPS-induced cardiac dysfunction. Antibody blockade or absence of ICAM-1 (gene knockout) also abrogated LPS-induced cardiac dysfunction but did not reduce neutrophil accumulation. Neutrophil depletion (vinblastine or antibody) did not protect from LPS-induced myocardial dysfunction. Our results suggest that although endotoxemic myocardial dysfunction requires both ICAM-1 and VCAM-1, it occurs independent of neutrophil accumulation.     

秦皮甲素对AGEs致损的ECV304细胞增殖及氧化应激的影响

为研究秦皮甲素对血管内皮细胞的保护作用,采用CCK-8法观察秦皮甲素对体外AGEs培养的人脐静脉内皮细胞增殖的影响。检测不同浓度AGEs以及秦皮甲素作用后对内皮细胞一氧化氮(NO)、不对称二甲基精氨酸(ADMA)水平的影响以及内皮细胞氧化应激有关指标:活性氧簇(reactive oxygen species,ROS)、丙二醛(malondialdehyde,MDA)、超氧化物歧化酶(superoxide dismutase,SOD);脂肪代谢相关指标:乳酸脱氢酶(lactic dehydrogenase,LDH)、总胆固醇(total cholesterol,CHO)、甘油三酯(triglyceride,TG)和低密度脂蛋白(low density lipoprotein,LDL),同时分别检测粘附相关因子:血管细胞粘附分子-1(VCAM-1)和细胞间粘附分子-1(ICAM-1)的表达水平。结果显示200 mg/L AGEs对人内皮细胞ECV304增殖有显著抑制作用,秦皮甲素可对抗AGEs导致的内皮细胞增殖抑制,并呈浓度依赖性。在25 mg/L时,保护效应达到最高。秦皮甲素可抵抗ROS生成。同时可改善细胞的脂类代谢:胆固醇、LDL以及TG含量在秦皮甲素作用后改善明显。秦皮甲素可显著抑制内皮粘附因子VCAM-1的表达。秦皮甲素还可上调NO水平,下调ADMA水平。总之,秦皮甲素可有效促进人血管内皮细胞增殖并在改善氧化应激,脂代谢,粘附因子和NO释放等方面发挥作用。     

Trophoblast interactions with endothelial cells are increased by interleukin-1beta and tumour necrosis factor alpha and involve vascular cell adhesion molecule-1 and alpha4beta1

Interactions between fetal extravillous trophoblast cells and maternal uterine cells are of critical importance in successful placentation. In the first trimester, trophoblasts invade the uterine environment and reach the spiral arteries where they interact with vascular cells; however, little is known of the nature of these interactions. We have developed a fluorescent binding assay to investigate the contact between trophoblasts and endothelial cells and to determine its regulation by cytokines and adhesion molecules. Stimulation of an endothelial cell line (SGHEC-7) with interleukin-1beta or tumour necrosis factor-alpha significantly increased adhesion of the first-trimester extravillous trophoblast-derived cell line, SGHPL-4. Using blocking antibodies, vascular cell adhesion molecule-1 (VCAM-1) and integrin alpha4beta1 (VLA-4), but not intercellular adhesion molecule-1 (ICAM-1), were shown to be important in trophoblast binding to activated endothelial cells. SGHPL-4 cells were shown to express HLA-G, alpha4beta1 and ICAM-1 at high levels and LFA-1 and VCAM-1 at lower levels. ICAM-1 and VCAM-1 are expressed on SGHEC-7 cells and their expression was confirmed on primary decidual endothelial cells. In conclusion, we have demonstrated the importance of VCAM-1 and alpha4beta1 in trophoblasts-endothelial interactions. Improved knowledge of the nature of these fetal-maternal interactions will have implications for understanding situations when placentation is compromised.     

Levels of soluble VCAM-1, soluble ICAM-1, and soluble E-selectin in patients with tuberculous pleuritis

Tuberculosis is characterized by the presence of activated mononuclear cells both in the peripheral circulation and in pleural fluid. Expression and up-regulation of adhesion molecules is the basis of cell-cell adhesion in granuloma formation and in leukocyte migration to the inflammatory site. Soluble isoforms of adhesion molecules have been described, and their expression at high levels indicated an activated state. The purpose of this study was to evaluate levels of soluble adhesion molecules in serum and pleural fluid from patients with tuberculous pleural effusions, compared with non-tuberculous pleural effusions. We analysed levels of soluble vascular cell adhesion molecule-1 (s.VCAM-1), soluble intercellular adhesion molecule-1 (s.ICAM-1), and soluble E-selectin (sE-selectin) in serum and pleural fluid from patients with tuberculous pleuritis, by sandwich ELISA. Serum levels of s.ICAM-1 and s.VCAM-1 in patients with tuberculosis were higher than those in healthy controls (p < 0.001). Levels of sE-selectin levels were in the normal range compared with control groups. In pleural fluid, levels of s.VCAM-1 and s.ICAM-1 were increased in pleural effusions. Patients with tuberculous pleural effusion exhibited high levels of s.ICAM-1 compared with patients with neoplastic pleural involvement. Up-regulation of s.VCAM-1 and s.ICAM-1 in serum, along with increased levels of sE-selectin in pleural effusions from tuberculous patients, may result in transmigration of activated inflammatory cells inducing pleural damage, which may contribute to the pathological processes involved.     

Enteric microflora contribute to constitutive ICAM-1 expression on vascular endothelial cells

Quantitative estimates of endothelial cell adhesion molecule expression have revealed that some adhesion molecules [e.g., intercellular adhesion molecule-1 (ICAM-1)] are abundantly expressed in different vascular beds under normal conditions. The objective of this study was to determine whether the enteric microflora contribute to the constitutive expression of ICAM-1 and other endothelial cell adhesion molecules in the gastrointestinal tract and other regional vascular beds. The dual radiolabeled monoclonal antibody technique was used to measure endothelial expression of ICAM-1, ICAM-2, vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in conventional, germ-free mice and germ-free mice receiving the cecal contents of conventional mice to reestablish the enteric microflora (total association). Constitutive ICAM-1 expression was significantly lower in the splanchnic organs (pancreas, stomach, small and large intestine, mesentery, and liver), kidneys, skeletal muscle, and skin of germ-free mice compared with their conventional counterparts. These differences were abolished after total association of germ-free mice with the indigenous gastrointestinal flora. The expression of ICAM-2, VCAM-1, and E-selectin in the various tissues studied did not differ between conventional and germ-free mice. These findings indicate that the indigenous gastrointestinal microflora are responsible for a significant proportion of the basal ICAM-1 expression detected in both intestinal and extraintestinal tissues.     

The 18-kDa Translocator Protein Inhibits Vascular Cell Adhesion Molecule-1 Expression via Inhibition of Mitochondrial Reactive Oxygen Species

Translocator protein 18 kDa (TSPO) is a mitochondrial outer membrane protein and is abundantly expressed in a variety of organ and tissues. To date, the functional role of TSPO on vascular endothelial cell activation has yet to be fully elucidated. In the present study, the phorbol 12-myristate 13-acetate (PMA, 250 nM), an activator of protein kinase C (PKC), was used to induce vascular endothelial activation. Adenoviral TSPO overexpression (10–100 MOI) inhibited PMA-induced vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) expression in a dose dependent manner. PMA-induced VCAM-1 expressions were inhibited by Mito-TEMPO (0.1–0.5 μM), a specific mitochondrial antioxidants, and cyclosporin A (1–5 μM), a mitochondrial permeability transition pore inhibitor, implying on an important role of mitochondrial reactive oxygen species (ROS) on the endothelial activation. Moreover, adenoviral TSPO overexpression inhibited mitochondrial ROS production and manganese superoxide dismutase expression. On contrasts, gene silencing of TSPO with siRNA increased PMA-induced VCAM-1 expression and mitochondrial ROS production. Midazolam (1–50 μM), TSPO ligands, inhibited PMA-induced VCAM-1 and mitochondrial ROS production in endothelial cells. These results suggest that mitochondrial TSPO can inhibit PMA-induced endothelial inflammation via suppression of VCAM-1 and mitochondrial ROS production in endothelial cells.     

7-Ketocholesterol enhances the expression of adhesion molecules on human aortic endothelial cells by increasing the production of reactive oxygen species

Abstract

The aim of the present study was to assess the expression of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), monocytic adhesion of human aortic endothelial cells (HAECs), and the production of intracellular reactive oxygen species (ROS), when HAECs were stimulated by 7-ketocholesterol. 7-ketocholesterol enhances surface expression of ICAM-1 and VCAM-1 as determined by EIA, induces their mRNA expression by RT-PCR, and stimulates adhesiveness of HAECs to U937 monocytic cells. We confirmed up-regulation of ROS production of HAECs treated with 7-ketocholesterol. Although the surface expression of ICAM-1 and VCAM-1 on HAECs treated with 7-ketocholesterol increased in a time-dependent manner, α-tocopherol inhibited this increase of the surface expression of ICAM-1 and VCAM-1. In the monocytic adhesion assay, adhesion of U937 to HAECs treated with 7-ketocholesterol was enhanced, but monoclonal anti-ICAM-1 and VCAM-1 antibodies reduced the endothelial adhesiveness. In conclusion, this study suggests that the endothelial adhesiveness to monocytic cells that was increased by 7-ketocholesterol was associated with enhanced expression of ICAM-1 and VCAM-1 mediated by ROS production.     

Cytokine and endothelial cell adhesion molecule expression in interleukin-10-deficient mice

The objectives of this study were to quantify cytokine mRNA levels and endothelial cell adhesion molecule message and protein expression in healthy wild-type and interleukin-10-deficient (IL-10(-/-)) mice that develop spontaneous and chronic colitis. We found that colonic message levels of IL-1, IL-6, tumor necrosis factor-alpha, interferon-gamma, lymphotoxin-beta, and transforming growth factor-beta were elevated in colitic mice 10- to 35-fold compared with their healthy wild-type controls. In addition, colonic message levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) were found to be increased 10-, 5-, and 23-fold, respectively, in colitic IL-10(-/-) mice compared with their wild-type controls. Immunoradiolabeling as well as immunohistochemistry revealed large and significant increases in vascular surface expression of colonic ICAM-1, VCAM-1, and MAdCAM-1 in the mucosa as well as the submucosa of the colons of colitic mice. These data are consistent with the hypothesis that deletion of IL-10 results in the sustained production of proinflammatory cytokines, leading to the upregulation of adhesion molecules and infiltration of mononuclear and polymorphonuclear leukocytes into the cecal and colonic interstitium.     

Eosinophil adhesion to cholinergic nerves via ICAM-1 and VCAM-1 and associated eosinophil degranulation

In vivo, eosinophils localize to airway cholinergic nerves in antigen-challenged animals, and inhibition of this localization prevents antigen-induced hyperreactivity. In this study, the mechanism of eosinophil localization to nerves was investigated by examining adhesion molecule expression by cholinergic nerves. Immunohistochemical and functional studies demonstrated that primary cultures of parasympathetic nerves express vascular cell adhesion molecule-1 (VCAM-1) and after cytokine pretreatment with tumor necrosis factor-alpha and interferon-gamma intercellular adhesion molecule-1 (ICAM-1). Eosinophils adhere to these parasympathetic neurones after cytokine pretreatment via a CD11/18-dependent pathway. Immunohistochemistry and Western blotting showed that a human cholinergic nerve cell line (IMR-32) expressed VCAM-1 and ICAM-1. Inhibitory experiments using monoclonal blocking antibodies to ICAM-1, VCAM-1, or CD11/18 and with the very late antigen-4 peptide inhibitor ZD-7349 showed that eosinophils adhered to IMR-32 cells via these adhesion molecules. The protein kinase C signaling pathway is involved in this process as a specific inhibitor-attenuated adhesion. Eosinophil adhesion to IMR-32 cells was associated with the release of eosinophil peroxidase and leukotriene C(4). Thus eosinophils adhere to cholinergic nerves via specific adhesion molecules, and this leads to eosinophil activation and degranulation; this may be part of the mechanism of eosinophil-induced vagal hyperreactivity.     

RORalpha1 and RORalpha4 suppress TNF-alpha-induced VCAM-1 and ICAM-1 expression in human endothelial cells

Retinoic acid receptor-related orphan receptor-alpha (RORalpha) is a nuclear orphan receptor. Adenovirus-mediated overexpression of RORalpha1 and RORalpha4 suppressed tumor necrosis factor-alpha (TNF-alpha)-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1) in human umbilical vein endothelial cells. Overexpression of RORalpha1 and RORalpha4 also suppressed TNF-alpha-stimulated translocation of p50 and p65 to the nucleus. In contrast, dominant-negative deletion mutants of RORalpha1 and RORalpha4 failed to suppress the induction of VCAM-1 and ICAM-1 and translocations of p50 and p65. These results suggest that RORalpha1 and RORalpha4 regulate the inflammatory responses via inhibition of the nuclear factor-kappaB signaling pathway in endothelial cells.     

7-Ketocholesterol enhances the expression of adhesion molecules on human aortic endothelial cells by increasing the production of reactive oxygen species

The aim of the present study was to assess the expression of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), monocytic adhesion of human aortic endothelial cells (HAECs), and the production of intracellular reactive oxygen species (ROS), when HAECs were stimulated by 7-ketocholesterol. 7-ketocholesterol enhances surface expression of ICAM-1 and VCAM-1 as determined by EIA, induces their mRNA expression by RT-PCR, and stimulates adhesiveness of HAECs to U937 monocytic cells. We confirmed up-regulation of ROS production of HAECs treated with 7-ketocholesterol. Although the surface expression of ICAM-1 and VCAM-1 on HAECs treated with 7-ketocholesterol increased in a time-dependent manner, alpha-tocopherol inhibited this increase of the surface expression of ICAM-1 and VCAM-1. In the monocytic adhesion assay, adhesion of U937 to HAECs treated with 7-ketocholesterol was enhanced, but monoclonal anti-ICAM-1 and VCAM-1 antibodies reduced the endothelial adhesiveness. In conclusion, this study suggests that the endothelial adhesiveness to monocytic cells that was increased by 7-ketocholesterol was associated with enhanced expression of ICAM-1 and VCAM-1 mediated by ROS production.     

Simvastatin modulates TNFalpha-induced adhesion molecules expression in human endothelial cells

Adhesion and transendothelial migration of leukocytes into the vascular wall is a crucial step in atherogenesis. Expression of cell adhesion molecules by endothelial cells plays a leading role in this process. We investigated the effect of simvastatin, an inhibitor of HMG-CoA reductase administered to reduce plasma levels of LDL-cholesterol, on the expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) by human umbilical vein endothelial cells (HUVEC) stimulated with tumor necrosis factor alpha (TNFalpha). We found the expression to be significantly inhibited by the drug in a time and concentration-dependent manner and to a greater extent in the case of VCAM-1 as compared with ICAM-1. In TNFalpha-stimulated HUVEC, simvastatin decreased VCAM-1 and ICAM-1 mRNA levels, inhibited TNFalpha-induced activation of nuclear factor kappaB (NF-kappaB) and enhanced expression of peroxisome proliferator-activated receptor alpha (PPARalpha). These effects were associated with reduction of adherence of monocytes and lymphocytes to HUVEC. The present findings suggest that the benefits of statins in vascular disease may include the inhibition of expression of VCAM-1 and ICAM-1 through effects on NF-kappaB.     

Butyrate inhibits cytokine-induced VCAM-1 and ICAM-1 expression in cultured endothelial cells: the role of NF-kappaB and PPARalpha

Adhesion and migration of leukocytes into the surrounding tissues is a crucial step in inflammation, immunity, and atherogenesis. Expression of cell adhesion molecules by endothelial cells plays a leading role in this process. Butyrate, a natural short-chain fatty acid produced by bacterial fermentation of dietary fiber, has been attributed with anti-inflammatory activity in inflammatory bowel disease. Butyrate in vitro is active in colonocytes and several other cell types. We have studied the effect of butyrate on expression of endothelial leukocyte adhesion molecules by cytokine-stimulated human umbilical vein endothelial cells (HUVEC). Pretreatment of HUVEC with butyrate-inhibited tumor necrosis factor-alpha (TNFalpha)-induced expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) in a time and concentration-dependent manner. Butyrate at 10 mM/L inhibited interleukin-1 (IL-1)-stimulated VCAM-1 and ICAM-1 expression. The effect of butyrate on cytokine-stimulated VCAM-1 expression was more pronounced than in the case of ICAM-1. Butyrate decreased TNFalpha-induced expression of mRNA for VCAM-1 and ICAM-1. Suppressed expression of VCAM-1 and ICAM-1 was associated with reduced adherence of monocytes and lymphocytes to cytokine-stimulated HUVEC. Butyrate inhibited TNFalpha-induced activation of nuclear factor-kappaB (NF-kappaB) in HUVEC. Finally, butyrate enhanced peroxisome proliferator-activated receptor-alpha (PPARalpha) expression in HUVEC. These results demonstrate that butyrate may have anti-inflammatory properties not only in colonocytes but also in endothelial cells. The anti-inflammatory and (perhaps) antiatherogenic properties of butyrate may partly be attributed to an effect on activation of NF-kappaB and PPARalpha and to the associated expression of VCAM-1 and ICAM-1. The present findings support further investigations on the therapeutic benefits of butyrate in several pathological events involving leukocyte recruitment.