VCAM-1 expression precedes macrophage infiltration into subendothelium of vein grafts interposed into carotid arteries in hypercholesterolemic rabbits--a potential role in vein graft atherosclerosis

Neutrophil extracellular traps induce intrahepatic thrombotic tendency and liver damage in cholestatic liver disease

BACKGROUND

Cholestatic liver diseases induce local and systemic hypercoagulation, with neutrophil extracellular traps (NETs) serving as major drivers. These NETs have been linked to decreased liver function in patients with obstructive jaundice. However, the impact of NETs on liver hypercoagulation in cholestatic liver disease remains unknown.

METHODS

We utilized bile duct ligation to create experimental mice and analyzed NETs formation in the liver. Fibrin deposition, tissue factor expression, and inflammation in the liver were visualized through western blot and immunohistochemical techniques. LSECs were incubated with isolated NETs, and we detected endothelial procoagulant activity using coagulation protein production assays and measuring endothelial permeability. In both in vivo and in vitro settings, DNase I was applied to clarify the effect of NETs on intrahepatic hypercoagulability, hepatotoxicity, LSEC, and macrophage activation or injury.

RESULTS

Bile duct ligation mice exhibited significantly increased levels of NETs in liver tissue, accompanied by neutrophil infiltration, tissue necrosis, fibrin deposition, and thrombophilia compared to sham mice. Notably, NETs resulted in phosphatidylserine and tissue factor exposure on LSEC, enhancing coagulation Factor Xa and thrombin production. The enhanced procoagulant activity could be reversed by degrading NETs with DNase I. Additionally, NETs-induced permeability changes in LSECs, characterized by increased VE-cadherin expression and F-actin retraction, which could be rescued by DNase I. Meanwhile, NET formation is associated with KC activation and the formation of inflammatory factors.

CONCLUSIONS

NETs promote intrahepatic activation of coagulation and inflammation, leading to liver tissue injury. Strategies targeting NET formation may offer a potential therapeutic approach for treating cholestatic liver disease.

Chitosan Nanoparticles in Atherosclerosis-Development to Preclinical Testing

Chitosan is a natural biopolymer that is present in an abundant supply in sources such as crustacean shells, mushrooms, and insect exoskeletons. It can be used to make a variety of types of drug formulations and is generally safe to use in vivo; plus, it has inherent cholesterol-reducing properties. While an abundance of papers has tested this biopolymer in nanoparticles in cancer and diabetes research, there is a lag of usage, and hence the paucity of information, in the area of cardiovascular research, specifically in atherosclerosis, the topic of this review. This review highlights some of the deficiencies in this niche area of research, examines the range of chitosan nanoparticles that have been researched to date, and proposes several ways forward to advance this field. Nanoparticles used for both diagnostic and therapeutic purposes are reviewed, with a discussion on how these nanoparticles could be better researched in future and what lays ahead as the field potentially moves towards clinical trials in future.

Complement Inhibition Alleviates Cholestatic Liver Injury Through Mediating Macrophage Infiltration and Function in Mice

BACKGROUND AND AIMS

Cholestatic liver injury (CLI), which is associated with inflammatory reactions and oxidative stress, is a serious risk factor for postoperative complications. Complement system is involved in a wide range of liver disorders, including cholestasis. The present study assessed the role of complement in CLI and the therapeutic effect of the site-targeted complement inhibitor CR2-Crry in CLI.

METHODS

Wild-type and complement gene deficient mice underwent common bile duct ligation (BDL) to induce CLI or a sham operation, followed by treatment with CR2-Crry or GdCl3. The roles of complement in CLI and the potential therapeutic effects of CR2-Crry were investigated by biochemical analysis, flow cytometry, immunohistochemistry, ELISA, and quantitative RT-PCR.

RESULTS

C3 deficiency and CR2-Crry significantly reduced liver injuries in mice with CLI, and also markedly decreasing the numbers of neutrophils and macrophages in the liver. C3 deficiency and CR2-Crry also significantly reduced neutrophil expression of Mac-1 and liver expression of VCAM-1. More importantly, C3 deficiency and CR2-Crry significantly inhibited M1 macrophage polarization in these mice. Intravenous injection of GdCl3 inhibited macrophage infiltration and activation in the liver. However, the liver injury increased significantly. BDL significantly increased the level of lipopolysaccharide (LPS) in portal blood, but not in peripheral blood. GdCl3 significantly increased LPS in peripheral blood, suggesting that macrophages clear portal blood LPS. Oral administration of ampicillin to in GdCl3 treated mice reduced LPS levels in portal blood and alleviated liver damage. In contrast, intraperitoneal injection LPS increased portal blood LPS and reversed the protective effect of ampicillin. Interestingly, C3 deficiency did not affect the clearance of LPS.

CONCLUSIONS

Complement is involved in CLI, perhaps mediating the infiltration and activation of neutrophils and macrophage M1 polarization in the liver. C3 deficiency and CR2-Crry significantly alleviated CLI. Inhibition of complement could preserve the protective function of macrophages in clearing LPS, suggesting that complement inhibition could be useful in treating CLI.

The Cholesteryl Ester Transfer Protein Inhibitor, des-Fluoro-Anacetrapib, Prevents Vein Bypass-induced Neointimal Hyperplasia in New Zealand White Rabbits

Coronary artery bypass grafting is among the most commonly performed of all cardiovascular surgical procedures. However, graft failure due to stenosis reduces the long-term benefit of the intervention. This study asks if elevating plasma high density lipoprotein cholesterol (HDL-C) levels by inhibition of cholesteryl ester transfer protein (CETP) activity with des-fluoro-anacetrapib, an analog of the CETP inhibitor anacetrapib, prevents vein bypass-induced neointimal hyperplasia. NZW rabbits were placed on a normal chow diet or chow containing 0.14% (wt/wt) des-fluoro-anacetrapib for 6 weeks. Bypass grafting of the jugular vein to the common carotid artery was performed 2 weeks after starting dietary des-fluoro-anacetrapib supplementation. The animals were euthanised 4 weeks post-bypass grafting. Relative to control, dietary supplementation with des-fluoro-anacetrapib reduced plasma CETP activity by 89 ± 6.9%, increased plasma apolipoprotein A-I levels by 24 ± 5.5%, increased plasma HDL-C levels by 93 ± 26% and reduced intimal hyperplasia in the grafted vein by 38 ± 6.2%. Des-fluoro-anacetrapib treatment was also associated with decreased bypass grafting-induced endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), endothelial dysfunction, and smooth muscle cell (SMC) proliferation in the grafted vein. In conclusion, increasing HDL-C levels by inhibiting CETP activity is associated with inhibition of intimal hyperplasia in grafted veins, reduced inflammatory responses, improved endothelial function, and decreased SMC proliferation.

Expression profiles of microRNAs in oxidized low-density lipoprotein-stimulated RAW 264.7 cells

Macrophage-derived foam cells were one of the hallmarks of atherosclerosis, and microRNAs played an important role in the formation of foam cells. In order to explore the roles of miRNA in the formation of foam cells, we investigated miRNA expression profiles in foam cells through high-throughput sequencing technology. A total of 84 miRNAs were differentially expressed between RAW 264.7 macrophages and foam cells induced by ox-LDL. Thirty miRNAs were upregulated and 54 miRNAs were downregulated. GO terms and KEGG pathways analysis revealed that the target genes of most of DE miRNAs were mainly enriched in "cell differentiation," "endocytosis," "MAPK signaling pathway," and "FoxO signaling pathway." The target genes of some DE miRNAs were enriched in "Insulin signaling pathway," "Hippo signaling pathway," "TNF signaling pathway," "NF-kappa B signaling pathway," and "cell death." Using bioinformatics analyses and dual-luciferase reporter assays, we found that miR-28a-5p and miR-30c-1-3p directly inhibited LRAD3 and LOX-1 mRNA expression through targeting the 3'UTR of LRAD3 and LOX-1 mRNA, respectively. Our study indicates that miRNAs are extensively involved in the formation of foam cells, and provides a valuable resource for further study the role of miRNAs in atherosclerosis.

Novel nanostructural contrast for magnetic resonance imaging of endothelial inflammation: targeting SPIONs to vascular endothelium

This study aimed to develop superparamagnetic iron oxide nanoparticles (SPIONs) targeted to the areas of vascular endothelium changed in the initial inflammation process, a first step of numerous cardiovascular diseases.

Low WSS Induces Intimal Thickening, while Large WSS Variation and Inflammation Induce Medial Thinning, in an Animal Model of Atherosclerosis

OBJECTIVE

Atherosclerotic plaque development in the arterial wall is the result of complex interaction between the wall's endothelial layer and blood hemodynamics. However, the interaction between hemodynamic parameters and inflammation in plaque evolution is not yet fully understood. The aim of the present study was to investigate the relation between wall shear stress (WSS) and vessel wall inflammation during atherosclerotic plaque development in a minipig model of carotid stenosis.

METHODS

A surgical procedure was performed to create left common carotid artery stenosis by placement of a perivascular cuff in minipigs under atherogenic diet. Animals were followed up on 3T MRI, 1 week after surgery and 3, 6, and 8 months after initiation of the diet. Computational fluid dynamics simulation estimated WSS distribution for the first imaging point. Vascular geometries were co-registered for direct comparison of plaque development and features (Gadolinium- and USPIO-Contrast Enhanced MRI, for permeability and inflammation respectively) with the initial WSS. Histological analysis was performed and sections were matched to MR images, based on spatial landmarks.

RESULTS

Vessel wall thickening, permeability and inflammation were observed distally from the stenosis. They were eccentric and facing regions of normal wall thickness. Histological analysis confirmed eccentric plaque formation with lipid infiltration, intimal thickening and medial degradation. High phagocytic activity in the stenosis region was co-localized with high WSS, corresponding to intense medial degradation observed on histology samples.

CONCLUSION

Lower WSS promotes atherosclerotic plaque development distal to an induced stenosis. Vascular and perivascular inflammation locations were predominant in the high WSS stenosis segment, where medial thinning was the major consequence.

Animal models of atherosclerosis and magnetic resonance imaging for monitoring plaque progression

Atherosclerosis, the main cause of heart attack and stroke, is the leading cause of death in most modern countries. Preventing clinical events depends on a better understanding of the mechanism of atherosclerotic plaque destabilization. Our knowledge on the characteristics of vulnerable plaques in humans has grown past decades. Histological studies have provided a precise definition of high-risk lesions and novel imaging methods for human atherosclerotic plaque characterization have made significant progress. However the pathological mechanisms leading from stable lesions to the formation of vulnerable plaques remain uncertain and the related clinical events are unpredictable. An animal model mimicking human plaque destablization is required as well as an in vivo imaging method to assess and monitor atherosclerosis progression. Magnetic resonance imaging (MRI) is increasingly used for in vivo assessment of atherosclerotic plaques in the human carotids. MRI provides well-characterized morphological and functional features of human atherosclerotic plaque which can be also assessed in animal models. This review summarizes the most common species used as animal models for experimental atherosclerosis, the techniques to induce atherosclerosis and to obtain vulnerable plaques, together with the role of MRI for monitoring atherosclerotic plaques in animals.

Effect of shunting of collateral flow into the venous system on arteriogenesis and angiogenesis in rabbit hind limb

The aim of this study was to characterize the vascular remodeling in the external iliac artery (EIA) and the lower leg muscles in a rabbit shunt model created between the distal stump of the occluded femoral artery and the accompanying vein. Histology and immunoconfocal microscopy were used in this study. We found that: 1) both endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS (P-eNOS) proteins were significantly increased in the shunt-side EIA; 2) matrix metalloproteinase-2 (MMP-2) expression was 5.5 times in shunt side EIA over that in normal EIA; 3) intercellular adhension molecule-1 (ICAM-1) expression was strongly induced in endothelial cells (EC) and vascular adhension molecule-1 (VCAM-1) expression was significantly increased in both EC and the adventitia of the shunt-side EIA; 4) augmentation of cell proliferation and extracellular proteolysis by macrophage infiltration was observed in shunt-side EIA; 5) cell proliferation was active in shunt side EIA, but quiet in shunt side lower leg’s arterial vessels; 6) capillary density in shunt side lower leg muscles was 2 times over that in normal side.

In conclusion, our data demonstrate the paradigm that the power of shear stress takes the reins in arteriogenesis, whereas ischemia in angiogenesis, but not in arteriogenesis.

Statins suppress apolipoprotein CIII-induced vascular endothelial cell activation and monocyte adhesion

Aims

Activation of vascular endothelial cells (ECs) contributes importantly to inflammation and atherogenesis. We previously reported that apolipoprotein CIII (apoCIII), found abundantly on circulating triglyceride-rich lipoproteins, enhances adhesion of human monocytes to ECs in vitro. Statins may exert lipid-independent anti-inflammatory effects. The present study examined whether statins suppress apoCIII-induced EC activation in vitro and in vivo.

Methods and results

Physiologically relevant concentrations of purified human apoCIII enhanced attachment of the monocyte-like cell line THP-1 to human saphenous vein ECs (HSVECs) or human coronary artery ECs (HCAECs) under both static and laminar shear stress conditions. This process mainly depends on vascular cell adhesion molecule-1 (VCAM-1), as a blocking VCAM-1 antibody abolished apoCIII-induced monocyte adhesion. ApoCIII significantly increased VCAM-1 expression in HSVECs and HCAECs. Pre-treatment with statins suppressed apoCIII-induced VCAM-1 expression and monocyte adhesion, with two lipophilic statins (pitavastatin and atorvastatin) exhibiting inhibitory effects at lower concentration than those of hydrophilic pravastatin. Nuclear factor κB (NF-κB) mediated apoCIII-induced VCAM-1 expression, as demonstrated via loss-of-function experiments, and pitavastatin treatment suppressed NF-κB activation. Furthermore, in the aorta of hypercholesterolaemic Ldlr^−/− mice, pitavastatin administration in vivo suppressed VCAM-1 mRNA and protein, induced by apoCIII bolus injection. Similarly, in a subcutaneous dorsal air pouch mouse model of leucocyte recruitment, apoCIII injection induced F4/80+ monocyte and macrophage accumulation, whereas pitavastatin administration reduced this effect.

Conclusions

These findings further establish the direct role of apoCIII in atherogenesis and suggest that anti-inflammatory effects of statins could improve vascular disease in the population with elevated plasma apoCIII.

Animal, in vitro, and ex vivo models of flow-dependent atherosclerosis: role of oxidative stress

Atherosclerosis is an inflammatory disease preferentially occurring in curved or branched arterial regions, whereas straight parts of the arteries are protected, suggesting a close relationship between flow and atherosclerosis. However, evidence directly linking disturbed flow to atherogenesis is just emerging, thanks to the recent development of suitable animal models. In this article, we review the status of various animal, in vitro, and ex vivo models that have been used to study flow-dependent vascular biology and atherosclerosis. For animal models, naturally flow-disturbed regions such as branched or curved arterial regions as well as surgically created models, including arterio-venous fistulas, vascular grafts, perivascular cuffs, and complete, incomplete, or partial ligation of arteries, are used. Although in vivo models provide the environment needed to mimic the complex pathophysiological processes, in vitro models provide simple conditions that allow the study of isolated factors. Typical in vitro models use cultured endothelial cells exposed to various flow conditions, using devices such as cone-and-plate and parallel-plate chambers. Ex vivo models using isolated vessels have been used to bridge the gap between complex in vivo models and simple in vitro systems. Here, we review these flow models in the context of the role of oxidative stress in flow-dependent inflammation, a critical proatherogenic step, and atherosclerosis.

Cardiovascular and inflammatory effects of intratracheally instilled ambient dust from Augsburg, Germany, in spontaneously hypertensive rats (SHRs)

Rationale

Several epidemiological studies associated exposure to increased levels of particulate matter in Augsburg, Germany with cardiovascular mortality and morbidity. To elucidate the mechanisms of cardiovascular impairments we investigated the cardiopulmonary responses in spontaneously hypertensive rats (SHR), a model for human cardiovascular diseases, following intratracheal instillation of dust samples from Augsburg.

Methods

250 μg, 500 μg and 1000 μg of fine ambient particles (aerodynamic diameter <2.5 μm, PM_2.5-AB) collected from an urban background site in Augsburg during September and October 2006 (PM_2.5 18.2 μg/m³, 10,802 particles/cm³) were instilled in 12 months old SHRs to assess the inflammatory response in bronchoalveolar lavage fluid (BALF), blood, lung and heart tissues 1 and 3 days post instillation. Radio-telemetric analysis was performed to investigate the cardiovascular responses following instillation of particles at the highest dosage based on the inflammatory response observed.

Results

Exposure to 1000 μg of PM_2.5-AB was associated with a delayed increase in delta mean blood pressure (ΔmBP) during 2^nd-4^th day after instillation (10.0 ± 4.0 vs. -3.9 ± 2.6 mmHg) and reduced heart rate (HR) on the 3^rd day post instillation (325.1 ± 8.8 vs. 348.9 ± 12.5 bpm). BALF cell differential and inflammatory markers (osteopontin, interleukin-6, C-reactive protein, and macrophage inflammatory protein-2) from pulmonary and systemic level were significantly induced, mostly in a dose-dependent way. Protein analysis of various markers indicate that PM_2.5-AB instillation results in an activation of endothelin system (endothelin1), renin-angiotensin system (angiotensin converting enzyme) and also coagulation system (tissue factor, plasminogen activator inhibitor-1) in pulmonary and cardiac tissues during the same time period when alternation in ΔmBP and HR have been detected.

Conclusions

Our data suggests that high concentrations of PM_2.5-AB exposure triggers low grade PM mediated inflammatory effects in the lungs but disturbs vascular homeostasis in pulmonary tissues and on a systemic level by affecting the renin angiotensin system, the endothelin system and the coagulation cascade. These findings are indicative for promotion of endothelial dysfunction, atherosclerotic lesions, and thrombogeneis and, thus, provide plausible evidence that susceptible-predisposed individuals may develop acute cardiac events like myocardial infarction when repeatedly exposed to high pollution episodes as observed in epidemiological studies in Augsburg, Germany.

Association of plasma circulatory markers, Chlamydia pneumoniae, and high sensitive C-reactive protein in coronary artery disease patients of India

Plasma inflammatory markers have been shown to be predictors for cardiovascular risk, however, there is no study where the levels of plasma circulatory markers have been evaluated in coronary artery disease patients (CAD pts) positive for C. pneumoniae IgA and high sensitive C-reactive protein (hsCRP) which may help in better understanding of disease pathogenesis. A total of 192 patients and 192 controls attending the Cardiology Outpatient Department of Safdarjung Hospital were enrolled. The levels of plasma circulatory inflammatory markers were evaluated by ELISA. The levels of circulatory plasma markers (IL-4, IL-8, IL-13, ICAM-1, and VCAM-1) were significantly higher, whereas, levels of IL-10 and IFN-γ were significantly lower in CAD pts compared to healthy controls. The levels of IL-4, IL-8, and ICAM-1 (P = .007, .015, and .048) were significantly higher, however, IL-10 and IFN-γ were significantly lower (P < .001, < .001) in C. pneumoniae IgA positive CAD pts. The levels of IL-4, IL-8, IL-13, ICAM-1, and VCAM-1 were higher but not significant and levels of IL-10 and IFN-γ were significantly (P < .001, < .001) lower in hsCRP positive CAD pts. Our study suggested that circulatory cytokines, namely, IL-4, IL-8, and adhesive molecules like ICAM-1 were enhanced after infection with C. pneumoniae whereas in contrast to this IL-10 and IFN-λ were lowered. Suggesting the important role of these cytokines in progression of CAD.

Human urotensin II induces tissue factor and cellular adhesion molecules expression in human coronary endothelial cells: an emerging role for urotensin II in cardiovascular disease

BACKGROUND

Human urotensin II is an 11-aminoacid peptide with a controversial role in the human cardiovascular system. Indeed, urotensin effects on vascular reactivity and in heart failure are well documented, while its potential role in the pathophysiology of athero-thrombosis is still unknown. This study investigates the effects of urotensin on tissue factor (TF) and VCAM-1/ICAM-1 expression in human coronary endothelial cells (HCAECs).

METHODS AND RESULTS

Urotensin induced TF-mRNA transcription as demonstrated by real time PCR and expression of TF that was functionally active as demonstrated by procoagulant activity assay. In addition, urotensin induced expression of VCAM-1 and ICAM-1 as demonstrated by FACS analysis. VCAM-1 and ICAM-1 were functionally active because they increased leukocyte adhesivity to HCAECs. Urotensin-induced expression of TF and of VCAM-1/ICAM-1 was mediated through the Rho A-activation of the transcription factor, NF-kappaB, as demonstrated by EMSA. Indeed, lovastatin, an HMG-CoA reductase inhibitor, by modulating the Rho activation, and NF-kappaB inhibitors, suppressed the urotensin effects on TF and CAMs.

CONCLUSIONS

Data of the present study, although in vitro, describe the close relationship existing between urotensin II and athero-thrombosis, providing for the first time support for the view that this peptide might have not only vasoactive functions but it might be an effector molecule able to induce a pro-atherothrombotic phenotype in cells of the coronary circulation. Although future studies are required to clarify whether these mechanisms are also important in the clinical setting, this report supports an emerging new role for urotensin II in the pathogenesis and progression of cardiovascular disease.

HMG-CoA reductase inhibitors reduce nicotine-induced expression of cellular adhesion molecules in cultured human coronary endothelial cells

BACKGROUND

Smoking predisposes to the development of atherosclerosis and of its complications. The mechanisms responsible for these effects are not completely understood. We have investigated whether nicotine might promote a proatherosclerotic state in human coronary endothelial cells (HCAECs), studying the role of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors in preventing these phenomena.

METHODS AND RESULTS

Real-time PCR showed that nicotine induced a dose-dependent increase in mRNA levels for vascular cellular adhesion molecule-1 (VCAM-1)/intercellular adhesion molecule-1 (ICAM-1). Fluorescent-activated cell sorting analysis showed that nicotine induced expression of functionally active VCAM-1/ICAM-1, since they increased leukocyte adherence to HCAECs. Oxygen free radicals, Rho A and nuclear factor kappaB (NF-kappaB) play a pivotal role in modulating these effects. Indeed, nicotine caused oxygen free radical production as well as activation of Rho A and NF-kappaB pathways, evaluated by malondialdehyde levels, pulldown assay and by electrophoretic mobility shift assay, respectively. Superoxide dimutase, Rho A (Y-27639) and NF-kappaB inhibitors (pyrrolidine dithiocarbamate ammonium, Bay 11-7082) suppressed nicotine effects on CAM expression. HMG-CoA reductase inhibitors prevented these nicotine-mediated effects by inhibiting free radical generation and by modulating activation of Rho A and NF-kappaB pathways.

CONCLUSIONS

Nicotine promotes CAM expression on HCAECs, shifting them toward a proatherosclerotic state. These effects might explain, at least in part, the deleterious cardiovascular consequences of cigarette smoking. HMG-CoA reductase inhibitors play an important role in preventing these phenomena.

Nicotine induces mononuclear leukocyte adhesion and expression of adhesion molecules, VCAM and ICAM, in endothelial cells in vitro

The pathology of atherosclerotic cardiovascular disease (ASCVD) has been characterized as an inflammatory response to vessel injury. The initial steps of this response involve mononuclear leukocyte (MNL) attachment and infiltration into the vessel wall. Leukocyte adhesion is potentiated by expression of cellular adhesion molecules. Vascular cell adhesion molecule-1 (VCAM) and intracellular adhesion molecule-1 (ICAM) are markers of cellular activation and have the ability to attach leukocytes to the endothelium, which is an initial event in the inflammatory response in the vessel wall. Human umbilical vein endothelial cells (HUVEC) were plated in endothelial growth medium (EGM) on plastic coverslips and grown until cells were 75% confluent. Free base nicotine (FBN) was diluted in EGM to a concentration of 10(-8) M and added to experimental cells. At 3 hr, coverslips were removed and fixed. Immunohistochemical staining (IHCS) was performed using a monoclonal antibody to human ICAM and VCAM. Digital image analysis (DIA) was performed to quantify the expression of ICAM and VCAM. An intensity stain index (ISI) measuring area and intensity of stain/total cellular area was determined. Additional HUVEC grown in a similar manner were either exposed to 10(-8) M FBN in EGM or EGM control for 4 hr, then were exposed to MNL suspension for 10 min. Coverslips were removed, rinsed, and fixed. Hematoxylin and eosin staining was performed and cells examined under light microscopy. Leukocyte number per high power field (HPF) was counted and compared to controls. Data were analyzed using analysis of variants (ANOVA) and Student's t-test. Differences were considered significant if p < 0.05. ICAM and VCAM expression was absent in control cells. Nicotine exposure at 3 hr induced expression of VCAM (ISI = 30.85+/-0.77) and to a lesser extent ICAM (ISI = 16.6+/-1.39) (p < 0.001). MNL adhesion was markedly increased in cells exposed to nicotine (79.4+/-16.9/HPF) when compared to control cells (1.8+/-0.91/HPF) exposed to MNL (p < 0.01). These data show nicotine's ability to activate HUVEC as evidenced by induction of ICAM and VCAM expression in vitro. The biological effects of these adhesion molecules are demonstrated by a marked increase in MNL adhesion to HUVEC as demonstrated by leukocyte adhesion assay (LAA). MNL adhesion and subsequent migration into the intima, if occurring in vivo, may be a vital step in the pathogenesis of ASCVD associated with nicotine exposure.

Inflammation meets oxidation: NF-kappaB as a mediator of initial lesion development in atherosclerosis

Transcription factor nuclear factor-kappaB (NF-kappaB) and its target genes are involved in the pathogenesis of atherosclerosis, in addition to many other diseases. Monocyte recruitment into subendothelial space is primarily mediated by NF-kappaB-dependent gene expression, and this event is a crucial milestone, because it is nearly impossible to reverse the progression of the lesion after this point. Recent advances in our understanding of atherosclerosis as a disease of childhood enforces the necessity of developing novel approaches for prevention and treatment. Here, the authors address NF-kappaB as a major therapeutic target, especially for preventive measures, in the light of two main hypotheses of atherosclerosis: oxidation and inflammation.

Vascular Endothelial Growth Factor Gene Transfer Inhibits Neointimal Macrophage Accumulation in Hypercholesterolemic Rabbits

OBJECTIVE

This study aims to determine the effects of periadventitial vascular endothelial growth factor (VEGF) gene transfer on neointima formation and macrophage accumulation induced by collar placement around the carotid artery in hypercholesterolemic rabbits.

METHODS AND RESULTS

Collar placement around the carotid artery in cholesterol-fed rabbits induced intimal thickening with increased neointimal macrophage content. Liposome-mediated VEGF gene transfer, confirmed by transgene-specific RT-PCR, caused a marked inhibition of both intimal thickening and macrophage accumulation compared with a lacZ control gene. VEGF gene transfer was not accompanied by a significant increase in adventitial neovascularization. Collaring of carotid arteries in hypercholesterolemic rabbits also upregulated endothelial VCAM-1 expression. Inhibition of neointimal macrophage infiltration in VEGF-transduced, collared arteries was associated with decreased endothelial VCAM-1.

CONCLUSIONS

VEGF gene transfer inhibits collar-induced intimal thickening, macrophage accumulation, and VCAM-1 expression in cholesterol-fed rabbits. These findings support the concept that low-level VEGF expression can exert arterioprotective effects in the presence of high blood cholesterol.

Understanding and treating vein graft atherosclerosis

BACKGROUND

Vein grafts have been used as bypass conduits for coronary artery disease since the 1960s. This widely used treatment, however, is complicated by the development of changes in the vein graft, which resemble atherosclerosis and are often termed as such. They occur at about 10 years, which leads to the need for reoperation in some patients. The purpose of this review is to summarize the knowledge regarding the pathophysiology of vein graft "atherosclerosis," as well as promising new treatments for this disease.

METHODS

The relevant literature relating to the epidemiology, histology, cell and molecular pathophysiology and treatment of vein graft atherosclerosis is reviewed.

RESULTS

The development of vein graft atherosclerosis differs from arterial atherosclerosis. Studies have examined the role of trauma, lipids, vasoactive mediators, smooth muscle cell mitogens, smooth muscle cells apoptosis, adhesion molecules and proteases. Therapies have been developed to prevent vein graft atherosclerosis based on these studies and have been tested using animal models and in patients.

DISCUSSION

Promising new therapies have been developed based on current knowledge and further applications of genomics will allow for the further identification of risk factors and mechanistic insights. The use of arterial grafts such as the internal mammary artery, which have higher patency rates at 10 years compared with vein grafts as well as approaches to revascularize infarcted myocardium may one day replace the use of vascular conduits.