Activated nuclear factor-kappaB is present in the coronary vasculature in experimental hypercholesterolemia

Anti-atherosclerotic activity of aqueous extract of Ipomoea batatas (L.) leaves in high-fat diet-induced atherosclerosis model rats

OBJECTIVES

Cardiovascular diseases, especially atherosclerosis, are the leading cause of human mortality in Indonesia. Ipomoea batatas (L.) is a food plant used in Indonesian traditional medicine to treat cardiovascular diseases and related conditions. We assessed the anti-atherosclerotic activity of the aqueous extract of I. batatas leaves in a rat model of high-fat diet-induced atherosclerosis and its mechanism.

METHODS

The presence of amino acid content in the I. batatas L. purple variant was determined by liquid chromatography high-resolution mass spectrometry (LC-HRMS). Thirty male Wistar rats were divided into five groups (n=6/group), i.e., standard diet group (SD), high-fat diet group (HF), and HF plus I. batatas L. extracts orally (625; 1,250; or 2,500 mg/kg) groups. The numbers of macrophages and aortic wall thickness were analyzed histologically. Immunohistochemical analyses were performed to assess foam cells-oxidized low-density lipoprotein (oxLDL), endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor (VEGF) expression in the aorta.

RESULTS

LC-HRMS analysis showed nine amino acid content were identified from I. batatas L. In vivo study revealed that oral administration of I. batatas L. leaf extract alleviated foam cells-oxLDL formation and aortic wall thickness caused by high-fat diet atherosclerosis rats. Further, I. batatas L. leaf extract promoted the number of macrophages and modulated VEGF and eNOS expression in the aorta.

CONCLUSIONS

I. batatas L. leaf extract shows a positive anti-atherosclerosis effect. Furthermore, the mechanism may promote the macrophages, eNOS, VEGF expressions, and inhibition of foam cells-oxLDL formation and aortic wall thickness with the best dosage at 2,500 mg/kg. This could represent a novel approach to prevent cardiovascular diseases.

Effect of nebivolol on altered skeletal and cardiac muscles induced by dyslipidemia in rats: impact on oxidative and inflammatory machineries

AIM

High cholesterol diet is greatly linked to deleterious health consequences. In this work we tried to explore direct effects of high cholesterol diet on striated (skeletal and cardiac) muscle tissues and the mechanisms by which nebivolol could improve such harmful effects.

METHODS

The study included 24 healthy adult male albino rats weighing 200-220 grams that were assigned into four groups: control group, control drug group, high cholesterol diet fed groups; one untreated the other was treated with nebivolol.

RESULTS

In the cholesterol fed group, we found decreased blood HDL and NO with elevated total cholesterol, triglycerides, myoglobin, CK, LDH, ALP, in addition to elevated muscle tissue levels of HIF-1, NF-kB, MDA, and decreased expression of both eNOS, reduced GSH. Wire hanging test time was shorter in the high cholesterol group than control group rats, which was confirmed histologically by increased striated muscle fibre thickness and cytochrome area %. Nebivolol treatment ameliorated the effects of high cholesterol diet.

CONCLUSION

High cholesterol diet caused myopathic changes in rat striated muscle tissues mostly due to oxidative stress associated with enhanced NF-kB and HIF-1 expression. Nebivolol appears beneficial in the management of hypercholesterolaemia-induced striated muscle injury.

Ameliorations in dyslipidemia and atherosclerotic plaque by the inhibition of HMG-CoA reductase and antioxidant potential of phytoconstituents of an aqueous seed extract of Acacia senegal (L.) Willd in rabbits

The assigned work was aimed to examine the capability of phytoconstituents of an aqueous seed extract of Acacia senegal (L.) Willd to inhibit HMG-CoA reductase and regression of the atherosclerotic plaque. The chemical fingerprinting of the test extract was assessed by LC-MS/MS. Consequently, the analyses of in-vitro, in-vivo, and in-silico were executed by using the standard protocols. The in-vitro assessment of the test extract revealed 74.1% inhibition of HMG-CoA reductase. In-vivo assessments of the test extract indicated that treated hypercholesterolemic rabbits exhibited a significant (P≤0.001) amelioration in the biomarker indices of the dyslipidaemia i.e., atherogenic index, Castelli risk index(I&II), atherogenic coefficient along with lipid profile. Subsequently, significant reductions were observed in the atherosclerotic plaque and antioxidant levels. The in-silico study of molecular docking shown interactions capabilities of the leading phytoconstituents of the test extract i.e., eicosanoic acid, linoleic acid, and flavan-3-ol with target protein of HMG-CoA reductase. The values of RSMF and potential energy of top docked complexes were show significant interactions. Accordingly, the free energy of solvation, interaction angle, radius of gyration and SASA were shown significant stabilities of top docked complex. The cumulative data of results indicate phytoconstituents of an aqueous seed extract of Acacia senegal have capabilities to inhibit the HMG-CoA reductase and improve the levels of antioxidants.

Endothelial Dysfunction in Hypertension: Current Concepts and Clinical Implications

Endothelium plays a fundamental role in the cardiovascular system, forming an interface between blood and adjacent tissues by regulating the vascular tone through the synthesis of nitric oxide, prostaglandins and other relaxing factors. Endothelial dysfunction is characterized by vasoconstriction, cell proliferation and shifting toward a proinflammatory and prothrombic state. In hypertension endothelial dysfunction may be involved in the initiation and development of vascular inflammation, vascular remodeling, and atherosclerosis and is independently associated with increased cardiovascular risk. Different conditions such as impaired vascular shear stress, inflammation and oxidative stress, activation of the renin angiotensin system have been described as important pathophysiological mechanisms involved in the development of endothelial dysfunction. The release of extracellular vesicles by neighboring cells in the vascular wall has emerged as an important regulator of endothelial function and with potential antihypertensive properties and beneficial effects by counteracting the hypertension mediated organ damage. Furthermore, macrovesicles are emerging as an innovative therapeutic approach for vascular protection, allowing the delivery of bioactive molecules, such as miRNA and drugs interacting with the renin angiotensin system. In this review we summarize the available evidence about the pathophysiological implications of endothelial dysfunction in cardiovascular diseases, focusing on hypertension and its sequelae, and the potential innovative therapeutic strategies targeting the endothelium with the aim to improve vascular function and remodeling.

The pleotropic effects of fluvastatin on complement-mediated T-cell activation in hypercholesterolemia

T-cells orchestrate the inflammatory responses in atherosclerosis, and their function is modified by the lipoprotein milieu and complement activity. We investigated the effects of fluvastatin on the expression of complement decay-accelerating factor (DAF/CD55) antigen, and the levels of transcription factors in circulating T-cells in hypercholesterolemia. The hypercholesterolemic state was associated with the upregulation of DAF expression on circulating T-cells and increased levels nuclear factor kappa B (NF-kB) and interferon regulatory factor 4 (IRF4). Notably, the elevated levels of DAF and NF-kB expression persisted following treatment with fluvastatin. Therefore, the pleiotropic effects of fluvastatin are partially ascribed to its ability to mediate T-cell activation and regulate complement activity. Consequently, enhanced therapeutic interventions that targets complement-induced T-cell activation may be important in mitigating the development of atherosclerosis and major cardiovascular events in individuals with hypercholesterolemia.

Irisin in atherosclerosis

Irisin, a novel exercise-induced myokine, has been shown to play important roles in increasing white adipose tissue browning, regulating energy metabolism and improving insulin resistance. Growing evidence suggests a direct role for irisin in preventing atherosclerosis (AS) by inhibiting oxidative stress, improving dyslipidemia, facilitating anti-inflammation, reducing cellular damage and recovering endothelial function. In addition, some studies have noted that serum irisin levels play an essential role in cardiovascular diseases (CVDs) risk prediction, highlighting that irisin has the potential to be a useful predictive marker and therapeutic target of AS, especially in monitoring therapeutic efficacy. This review summarizes the understanding of irisin-mediated regulation in essential biological pathways and functions in atherosclerosis and prompts further exploitation of the biological properties of irisin in the pathogenesis of atherosclerosis.

The role of oxygen transport in atherosclerosis and vascular disease

Atherosclerosis and vascular disease of larger arteries are often associated with hypoxia within the layers of the vascular wall. In this review, we begin with a brief overview of the molecular changes in vascular cells associated with hypoxia and then emphasize the transport mechanisms that bring oxygen to cells within the vascular wall. We focus on fluid mechanical factors that control oxygen transport from lumenal blood flow to the intima and inner media layers of the artery, and solid mechanical factors that influence oxygen transport to the adventitia and outer media via the wall's microvascular system-the vasa vasorum (VV). Many cardiovascular risk factors are associated with VV compression that reduces VV perfusion and oxygenation. Dysfunctional VV neovascularization in response to hypoxia contributes to plaque inflammation and growth. Disturbed blood flow in vascular bifurcations and curvatures leads to reduced oxygen transport from blood to the inner layers of the wall and contributes to the development of atherosclerotic plaques in these regions. Recent studies have shown that hypoxia-inducible factor-1α (HIF-1α), a critical transcription factor associated with hypoxia, is also activated in disturbed flow by a mechanism that is independent of hypoxia. A final section of the review emphasizes hypoxia in vascular stenting that is used to enlarge vessels occluded by plaques. Stenting can compress the VV leading to hypoxia and associated intimal hyperplasia. To enhance oxygen transport during stenting, new stent designs with helical centrelines have been developed to increase blood phase oxygen transport rates and reduce intimal hyperplasia. Further study of the mechanisms controlling hypoxia in the artery wall may contribute to the development of therapeutic strategies for vascular diseases.

Metformin ameliorates the progression of atherosclerosis via suppressing macrophage infiltration and inflammatory responses in rabbits

AIMS

The present study aimed to investigate the possible effects of metformin on the progression of atherosclerosis in a rabbit model.

MAIN METHODS

Rabbits were randomly divided into three groups (n = 10): the control (Ctrl) group (fed with a chow diet), and two experimental groups, the AS group and the Met group (both received an atherogenic diet). After 2 weeks of acclimatization, the rabbits in the AS and Met groups were given a placebo and metformin, respectively, daily by gavage for 10 weeks. Plasma lipids and inflammatory cytokines were measured. The aorta was isolated for histological and immunohistochemical analysis. In vitro, human umbilical vein endothelial cells (HUVECs) were treated with metformin, and monocyte adhesion and adhesion molecule expression were measured.

KEY FINDINGS

Metformin reduced plasma inflammatory cytokine levels but did not alter lipid content. Compared with that in the AS group, the atherosclerosis burden in the Met group was significantly decreased. The lesional macrophage content was reduced, but the lesional collagen content was not affected in the metformin-treated rabbits, compared with the corresponding levels in the non-treated controls. Furthermore, the aortic mRNA expression levels of adhesion molecules and inflammatory cytokines in the Met group were also significantly reduced compared with those in the AS group. Metformin treatment reduced monocyte adhesion to endothelial cells (ECs) and adhesion molecule expression, and inhibited rabbit monocyte differentiation into macrophages and the macrophage inflammatory response.

SIGNIFICANCE

Our results suggest that metformin impeded the progression of atherosclerosis, possibly by suppressing macrophage infiltration and inflammatory responses.

Potential markers and metabolic processes involved in the mechanism of radiation-induced heart injury

Irradiation of normal tissues leads to acute increase in reactive oxygen/nitrogen species that serve as intra- and inter-cellular signaling to alter cell and tissue function. In the case of chest irradiation, it can affect the heart, blood vessels, and lungs, with consequent tissue remodelation and adverse side effects and symptoms. This complex process is orchestrated by a large number of interacting molecular signals, including cytokines, chemokines, and growth factors. Inflammation, endothelial cell dysfunction, thrombogenesis, organ dysfunction, and ultimate failing of the heart occur as a pathological entity - "radiation-induced heart disease" (RIHD) that is major source of morbidity and mortality. The purpose of this review is to bring insights into the basic mechanisms of RIHD that may lead to the identification of targets for intervention in the radiotherapy side effect. Studies of authors also provide knowledge about how to select targeted drugs or biological molecules to modify the progression of radiation damage in the heart. New prospective studies are needed to validate that assessed factors and changes are useful as early markers of cardiac damage.

The Interaction between Fluid Wall Shear Stress and Solid Circumferential Strain Affects Endothelial Gene Expression

Endothelial cells lining the walls of blood vessels are exposed simultaneously to wall shear stress (WSS) and circumferential stress (CS) that can be characterized by the temporal phase angle between WSS and CS (stress phase angle - SPA). Regions of the circulation with highly asynchronous hemodynamics (SPA close to -180°) such as coronary arteries are associated with the development of pathological conditions such as atherosclerosis and intimal hyperplasia whereas more synchronous regions (SPA closer to 0°) are spared of disease. The present study evaluates endothelial cell gene expression of 42 atherosclerosis-related genes under asynchronous hemodynamics (SPA=-180 °) and synchronous hemodynamics (SPA=0 °). This study used a novel bioreactor to investigate the cellular response of bovine aortic endothelial cells (BAECS) exposed to a combination of pulsatile WSS and CS at SPA=0 or SPA=-180. Using a PCR array of 42 genes, we determined that BAECS exposed to non-reversing sinusoidal WSS (10±10 dyne/cm2) and CS (4 ± 4%) over a 7 hour testing period displayed 17 genes that were up regulated by SPA = -180 °, most of them pro-atherogenic, including NFκB and other NFκB target genes. The up regulation of NFκB p50/p105 and p65 by SPA =-180° was confirmed by Western blots and immunofluorescence staining demonstrating the nuclear translocation of NFκB p50/p105 and p65. These data suggest that asynchronous hemodynamics (SPA=-180 °) can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA may be an important parameter characterizing arterial susceptibility to disease.

Inflammation and oxidative stress, rather than hypoxia, are predominant factors promoting angiogenesis in the initial phases of atherosclerosis

Micro-angiogenesis in the arterial wall has been observed during the development and progression of atherosclerosis. The aim of the present study was to examine whether inflammation, oxidative stress and hypoxia are involved in the process of early atherosclerotic micro-angiogenesis. A total of 24 rabbits were randomly divided into a normal diet group or a high-cholesterol (HC) diet group and were fed the corresponding diets for 4 weeks. The microvessel density (MVD), level of hypoxia and the levels of inflammatory markers and antioxidants in the arterial wall were detected using immunohistochemical and molecular biological techniques, respectively. The present results demonstrated that the MVD in the HC group was significantly higher (P<0.01) than that observed in the rabbits, which were provided with a normal diet, while hypoxia-inducible factor-1α levels did not exhibit marked changes in either of the two groups (P>0.05). The levels of inflammatory markers and antioxidants were significantly different between the two groups (P<0.05). The present study demonstrated that the primary factors, which promote micro-angiogenesis are possibly associated with an increase in inflammation and a decrease in the levels of antioxidants, as tissue hypoxia in the arterial wall at this stage was not evident.

Mechanisms of cardiac radiation injury and potential preventive approaches

In addition to cytostatic treatment and surgery, the most common cancer treatment is gamma radiation. Despite sophisticated radiological techniques however, in addition to irradiation of the tumor, irradiation of the surrounding healthy tissue also takes place, which results in various side-effects, depending on the absorbed dose of radiation. Radiation either damages the cell DNA directly, or indirectly via the formation of oxygen radicals that in addition to the DNA damage, react with all cell organelles and interfere with their molecular mechanisms. The main features of radiation injury besides DNA damage is inflammation and increased expression of pro-inflammatory genes and cytokines. Endothelial damage and dysfunction of capillaries and small blood vessels plays a particularly important role in radiation injury. This review is focused on summarizing the currently available data concerning the mechanisms of radiation injury, as well as the effectiveness of various antioxidants, anti-inflammatory cytokines, and cytoprotective substances that may be utilized in preventing, mitigating, or treating the toxic effects of ionizing radiation on the heart.

Endothelial microRNAs and atherosclerosis

The vascular endothelium, a thin layer of endothelial cells (ECs) that line the inner surface of blood vessels, is a critical interface between blood and all tissues. EC activation, dysfunction, and vascular inflammation occur when the endothelium is exposed to various insults such as proinflammatory cytokines, oxidative stress, hypertension, hyperglycemia, aging, and shear stress. These insults lead to the pathogenesis of a range of disease states, including atherosclerosis. Several signaling pathways, especially nuclear factor κB mediated signaling, play crucial roles in these pathophysiological processes. Recently, microRNAs (miRNAs) have emerged as important regulators of EC function by fine-tuning gene expression. In this review, we discuss how miRNAs regulate EC function and vascular inflammation in response to a variety of pathophysiologic stimuli. An understanding of the role of miRNAs in EC activation and dysfunction may provide novel targets and therapeutic opportunities for controlling atherosclerosis and other chronic inflammatory disease states.

Shear stress-initiated signaling and its regulation of endothelial function

Atherosclerosis develops preferentially at branches and curvatures of the arterial tree, where blood flow pattern is disturbed rather than being laminar, and wall shear stress has an irregular distribution without defined directions. The endothelium in the atherosusceptible regions, in comparison to that in atheroresistant regions, shows activation of proproliferative and proinflammatory gene expressions, reduced production of nitric oxide (NO), increased leukocyte adhesion, and permeability, as well as other atheroprone phenotypes. Differences in gene expressions and cell phenotypes have been detected in endothelia residing in native atherosusceptible and atheroresistant regions of the arteries, or in arteries from animal models with artificial creation of disturbed flow. Similar results have also been shown in in vitro systems that apply controlled shear stresses with or without clear directions to cultured endothelial cells in fluid-dynamically designed flow-loading devices. The available evidence indicates that the coordination of multiple signaling networks, rather than individual separate pathways, links the mechanical signals to specific genetic circuitries in orchestrating the mechanoresponsive networks to evoke comprehensive genetic and functional responses.

Comparative genome-wide transcriptional analysis of human left and right internal mammary arteries

In coronary artery bypass grafting (CABG), the combined use of left and right internal mammary arteries (LIMA and RIMA) - collectively known as bilateral IMAs (BIMAs) provides a survival advantage over the use of LIMA alone. However, gene expression in RIMA has never been compared to that in LIMA. Here we report a genome-wide transcriptional analysis of BIMA to investigate the expression profiles of these conduits in patients undergoing CABG. As expected, in comparing the BIMAs to the aorta, we found differences in pathways and processes associated with atherosclerosis, inflammation, and cell signaling - pathways which provide biological support for the observation that BIMA grafts deliver long-term benefits to the patients and protect against continued atherosclerosis. These data support the widespread use of BIMAs as the preferred conduits in CABG.

Translational studies of A20 in atherosclerosis and cardiovascular disease

Cardiovascular disease (CVD) is the biggest killer in the Western World despite significant advances in understanding its molecular underpinnings. Chronic inflammation, the classical hallmark of atherogenesis is thought to play a key pathogenic role in the development of atherosclerotic lesions from initiation of fatty streaks to plaque rupture. Over-representation of mostly pro-inflammatory nuclear factor kappa B (NF-kappaB) target genes within atherosclerotic lesions has led to the common-held belief that excessive NF-kappaB activity promotes and aggravates atherogenesis. However, mouse models lacking various proteins involved in NF-kappaB signaling have often resulted in conflicting findings, fueling additional investigations to uncover the molecular involvement of NF-kappaB and its target genes in atherogenesis. In this chapter we will review the role of the NF-kappaB-regulated, yet potent NF-kappaB inhibitory and anti-inflammatory gene A20/TNFAIP3 in atherogenesis, and highlight the potential use of its atheroprotective properties for the prevention and treatment of cardiovascular diseases.

Overexpression of NF-κB p65 in macrophages ameliorates atherosclerosis in apoE-knockout mice

The transcription factor NF-κB p65 is a key regulator in the regulation of an inflammatory response and in the pathology of atherosclerosis. However, there is no direct evidence for the role of NF-κB in macrophages in the development of atherosclerosis. We investigated whether macrophage overexpression of p65 in apoE-knockout mice could improve atherosclerosis. Transgenic (Tg) mice overexpressing p65 in macrophages were generated by crossing fatty acid-binding protein 4 (aP2) promoter-controlled p65 mice with apoE-knockout (KO) mice. Tg mice exhibited functional activation of NF-κB signaling in macrophages and fat tissues. We observed that the atherosclerotic lesion was 40% less in the Tg mice compared with the apoE-KO controls fed a standard atherogenic diet for 16 wk (n = 12). The Tg mice were leaner from reduced fat mass by increased energy expenditure. Moreover, the overexpression of p65 in macrophages suppressed foam cell formation. Our results show that there is 1) an increased fatty acid oxidation in macrophages, 2) a reduced scavenger receptor CD36 expression and lipid accumulation in microphages, 3) reduced-inflammation cytokines in serum, and 4) enhanced energy expenditure in Tg mice. Our data suggest that activation of NF-κB in macrophages has atheroprotective effects in mice by enhancing lipid metabolism and energy expenditure.

Carotid inflammation is unaltered by exercise in hypercholesterolemic Swine

INTRODUCTION

Reduction of vascular inflammation might contribute to the beneficial effects of exercise. We hypothesized that 1) exercise would reduce carotid endothelial vascular cell adhesion molecule-1 (VCAM-1) and that 2) in vivo detection of carotid inflammation can be achieved in a large animal model using contrast-enhanced ultrasound (CEU) with VCAM-1-targeted microbubbles (MBs).

METHODS

Familial hypercholesterolemic (FH) swine were divided into sedentary (Sed) and exercise-trained (Ex) groups. Ex pigs underwent 16-20 wk of treadmill aerobic exercise. At the end of the study, in vivo CEU with VCAM-1-targeted MBs and assessment of endothelial-dependent dilation (EDD) were performed in carotid arteries. VCAM-1 mRNA and protein expression were compared with markers of atherosclerotic disease and health, and in vitro EDD was assessed in carotid arteries.

RESULTS

Exercise training neither reduced inflammation nor improved EDD in carotid arteries of FH swine. Markers of atherosclerosis including VCAM-1 were prominent in the bifurcation compared with the proximal or distal common carotid artery and inversely associated with phosphorylated and total endothelial nitric oxide synthase. Signal intensity from VCAM-1-to-control MBs positively correlated with carotid VCAM-1 protein expression, validating our technique.

CONCLUSION

These results first demonstrate that aerobic exercise has no effect on carotid endothelial inflammatory markers and EDD in FH swine. Second, our findings indicate that CEU using VCAM-1-targeted MBs can detect inflammation in vivo, providing strong foundations for longitudinal studies examining the effect of therapeutic interventions on the inflammatory status of the endothelium.

IGFBP-3 inhibits cytokine-induced insulin resistance and early manifestations of atherosclerosis

Metabolic syndrome is associated with visceral obesity, insulin resistance and an increased risk of cardiovascular diseases. Visceral fat tissue primarily consists of adipocytes that secrete cytokines leading to a state of systemic inflammation in obese conditions. One of the IGF-independent functions of IGFBP-3 is its role as an anti-inflammatory molecule. Our study in obese adolescents show a decrease in total IGFBP-3 levels and increase in proteolyzed IGFBP-3 in circulation when compared to their normal counterparts and establishes a positive correlation between IGFBP-3 proteolysis and adiposity parameters as well as insulin resistance. In human adipocytes, we show that IGFBP-3 inhibits TNF-α-induced NF-κB activity in an IGF-independent manner, thereby restoring the deregulated insulin signaling and negating TNF-α-induced inhibition of glucose uptake. IGFBP-3 further inhibits TNF-α, CRP and high glucose-induced NF-κB activity in human aortic endothelial cells (HAECs) and subsequently suppresses monocyte adhesion to HAEC through the IGFBP-3 receptor. In conclusion, these findings suggest that reduced levels of IGFBP-3 in circulation and reduced expression of IGFBP-3 in macrophages in obesity may result in suppression of its anti-inflammatory functions and therefore IGFBP-3 may present itself as a therapeutic for obesity-induced insulin resistance and for events occurring in the early stages of atherosclerosis.

Poly(ADP-ribose) polymerase 1 inhibition protects against low shear stress induced inflammation

BACKGROUND

Atherosclerosis begins as local inflammation of vessels at sites of disturbed flow, where low shear stress (LSS) leads to mechanical irritation and plaque development and progression. Nuclear enzyme poly(ADP-ribose) polymerase 1 (PARP-1) is associated with the inflammation response during atherosclerosis. We investigated the role and underlying mechanism of PARP-1 in LSS-induced inflammation in human umbilical vein endothelial cells (HUVECs).

METHODS AND RESULTS

HUVECs were simulated by LSS (0.4Pa). PARP-1 expression was inhibited by ABT888 or siRNA. The inducible nitric oxide synthase (iNOS) and intercellular adhesion molecular-1 (ICAM-1) expression was regulated by LSS in a time dependent manner. LSS could increase superoxide production and 3-nitrotyrosine formation. LSS induced DNA damage as assessed by H2A.X phosphorylation and comet assay. Compared with cells under static, LSS increased PARP-1 expression and PAR formation via MEK/ERK signaling pathway. PARP-1 inhibition increased Sirt1 activity through an increased intracellular nicotinamide adenine dinucleotide (NAD(+)) level. Moreover, PARP-1 inhibition attenuated LSS-induced iNOS and ICAM-1 upregulation by inhibiting nuclear factor kappa B (NF-κB) nuclear translocation and activity, with a reduced NF-κB phosphorylation.

CONCLUSIONS

LSS induced oxidative damage and PARP-1 activation via MEK/ERK pathway. PARP-1 inhibition restored Sirt1 activity by increasing NAD(+) level and decreased iNOS and ICAM-1 expression by inhibiting NF-κB nuclear translocation and activity as well as NF-κB phosphorylation. PARP-1 played a fundamental role in LSS induced inflammation. Inhibition of PARP-1 might be a mechanism for treatment of inflammation response during atherosclerosis.

NF-κB and hypoxia: a double-edged sword in atherosclerosis

This Commentary highlights the article by Fang et al, which describes novel mouse models of chronic intermittent hypoxia (CIH)-induced atherosclerosis, revealing that loss of the NF-κB p50 subunit increased atherosclerosis in the presence of CIH.

The endothelium: influencing vascular smooth muscle in many ways

The endothelium, although only a single layer of cells lining the vascular and lymphatic systems, contributes in multiple ways to vascular homeostasis. Subsequent to the 1980 report by Robert Furchgott and John Zawadzki, there has been a phenomenal increase in our knowledge concerning the signalling molecules and pathways that regulate endothelial - vascular smooth muscle communication. It is now recognised that the endothelium is not only an important source of nitric oxide (NO), but also numerous other signalling molecules, including the putative endothelium-derived hyperpolarizing factor (EDHF), prostacyclin (PGI(2)), and hydrogen peroxide (H(2)O(2)), which have both vasodilator and vasoconstrictor properties. In addition, the endothelium, either via transferred chemical mediators, such as NO and PGI(2), and (or) low-resistance electrical coupling through myoendothelial gap junctions, modulates flow-mediated vasodilatation as well as influencing mitogenic activity, platelet aggregation, and neutrophil adhesion. Disruption of endothelial function is an early indicator of the development of vascular disease, and thus an important area for further research and identification of potentially new therapeutic targets. This review focuses on the signalling pathways that regulate endothelial - vascular smooth muscle communication and the mechanisms that initiate endothelial dysfunction, particularly with respect to diabetic vascular disease.

Anti-Atherogenic Effects of the Aqueous Extract of Rhubarb in Rats Fed an Atherogenic Diet

The present study was designed to investigate whether the aqueous extract of rhubarb (AR) could prevent the development of atherosclerosis through regulating vascular inflammatory processes in rats fed with an atherogenic diet. AR significantly reduced plasma low-density lipoprotein-cholesterol, and increased plasma high-density lipoprotein-cholesterol in rats fed with an atherogenic diet. AR inhibited vascular expressions of endothelin-1 (ET-1) and endothelin-converting enzyme (ECE) induced in rats with an atherogenic diet. On the other hand, AR augmented the vascular expression of endothelial nitric oxide synthase (ecNOS) and restored vascular nitric oxide (NO) production. Furthermore, AR suppressed the elevated expression of vascular nuclear factor-κB (NF-κB) p65 as well as adhesion molecules, including intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in rats fed with an atherogenic diet. Also, AR decreased endothelial expression of ICAM-1 and ET-1 in aorta. These results suggest that AR suppresses the development of atherosclerosis in the atherogenic-diet rat model through inhibiting vascular expressions of proinflammatory and adhesion molecules via the regulation of nitric oxide and endothelin system.

Humanin, a cytoprotective peptide, is expressed in carotid atherosclerotic [corrected] plaques in humans

OBJECTIVE

The mechanism of atherosclerotic plaque progression leading to instability, rupture, and ischemic manifestation involves oxidative stress and apoptosis. Humanin (HN) is a newly emerging endogenously expressed cytoprotective peptide. Our goal was to determine the presence and localization of HN in carotid atherosclerotic plaques.

METHODS AND RESULTS

Plaque specimens from 34 patients undergoing carotid endarterectomy were classified according to symptomatic history. Immunostaining combined with digital microscopy revealed greater expression of HN in the unstable plaques of symptomatic compared to asymptomatic patients (29.42±2.05 vs. 14.14±2.13% of plaque area, p<0.0001). These data were further confirmed by immunoblot (density of HN/β-actin standard symptomatic vs. asymptomatic 1.32±0.14 vs. 0.79±0.11, p<0.01). TUNEL staining revealed a higher proportion of apoptotic nuclei in the plaques of symptomatic patients compared to asymptomatic (68.25±3.61 vs. 33.46±4.46% of nuclei, p<0.01). Double immunofluorescence labeling revealed co-localization of HN with macrophages (both M1 and M2 polarization), smooth muscle cells, fibroblasts, and dendritic cells as well as with inflammatory markers MMP2 and MMP9.

CONCLUSIONS

The study demonstrates a higher expression of HN in unstable carotid plaques that is localized to multiple cell types within the plaque. These data support the involvement of HN in atherosclerosis, possibly as an endogenous response to the inflammatory and apoptotic processes within the atheromatous plaque.

The fatty acid oxidation product 15-A3t-isoprostane is a potent inhibitor of NFκB transcription and macrophage transformation

Fatty acids such as eicosapentaenoic acid (EPA) have been shown to be beneficial for neurological function and human health. It is widely thought that oxidation products of EPA are responsible for biological activity, although the specific EPA peroxidation product(s) which exert these responses have not yet been identified. In this work we provide the first evidence that the synthesized representative cyclopentenone IsoP, 15-A(3t)-IsoP, serves as a potent inhibitor of lipopolysaccharide-stimulated macrophage activation. The anti-inflammatory activities of 15-A(3t)-IsoP were observed in response not only to lipopolysaccharide, but also to tumor necrosis factor alpha and IL-1b stimulation. Subsequently, this response blocked the ability of these compounds to stimulate nuclear factor kappa b (NFκB) activation and production of proinflammatory cytokines. The bioactivity of 15-A(3t)-IsoP was shown to be dependent upon an unsaturated carbonyl residue which transiently adducts to free thiols. Site directed mutagenesis of the redox sensitive C179 site of the Ikappa kinase beta subunit, blocked the biological activity of 15-A(3t)-IsoP and NFκB activation. The vasoprotective potential of 15-A(3t)-IsoP was underscored by the ability of this compound to block oxidized lipid accumulation, a critical step in foam cell transformation and atherosclerotic plaque formation. Taken together, these are the first data identifying the biological activity of a specific product of EPA peroxidation, which is formed in abundance in vivo. The clear mechanism linking 15-A(3t)-IsoP to redox control of NFκB transcription, and the compound's ability to block foam cell transformation suggest that 15-A(3t)-IsoP provides a unique and potent tool to provide vaso- and cytoprotection under conditions of oxidative stress.

Cilostazol inhibits matrix invasion and modulates the gene expressions of MMP-9 and TIMP-1 in PMA-differentiated THP-1 cells

The invasion of monocytes into the subendothelium space plays an important role in the early stage of atherosclerosis. Cilostazol, a specific phosphodiesterase type III (PDE3) inhibitor, has been shown to exhibit anti-atherosclerotic effect. The present study aimed to investigate the modulating effects of cilostazol on monocyte invasion and the gene expressions of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1. We found that PMA significantly increased the invasive ability and the MMP-9 activity of THP-1 cells, as analyzed by matrix invasion assay and gelatin zymography, respectively. The increased expression of MMP-9 was demonstrated at both the RNA and protein levels by RT/real-time PCR and western blot analysis. These changes were markedly inhibited by cilostazol in a dose-dependent manner, which also could be observed when cAMP analog was used. On the contrary, the expression of TIMP-1, an inhibitor of MMP-9, was significantly upregulated by cilostazol dose dependently at both the RNA and protein levels. Reverse zymography further confirmed the increase of TIMP-1 activity after cilostazol treatment. The increase of TIMP-1 by cilostazol, however, was not cAMP-dependent. Cilostazol reduced the MMP-9 promoter activity and suppressed the nuclear translocation of NF-κB, indicating that the inhibitory effect of cilostazol is at the transcriptional level. In conclusion, the present study provides an additional mechanism underlying the anti-atherosclerotic effect of cilostazol by inhibiting the monocyte invasion and modulating the gene expressions of MMP-9 and TIMP-1 in monocytes upon differentiating to macrophages.

Effects of disturbed flow on vascular endothelium: pathophysiological basis and clinical perspectives

Vascular endothelial cells (ECs) are exposed to hemodynamic forces, which modulate EC functions and vascular biology/pathobiology in health and disease. The flow patterns and hemodynamic forces are not uniform in the vascular system. In straight parts of the arterial tree, blood flow is generally laminar and wall shear stress is high and directed; in branches and curvatures, blood flow is disturbed with nonuniform and irregular distribution of low wall shear stress. Sustained laminar flow with high shear stress upregulates expressions of EC genes and proteins that are protective against atherosclerosis, whereas disturbed flow with associated reciprocating, low shear stress generally upregulates the EC genes and proteins that promote atherogenesis. These findings have led to the concept that the disturbed flow pattern in branch points and curvatures causes the preferential localization of atherosclerotic lesions. Disturbed flow also results in postsurgical neointimal hyperplasia and contributes to pathophysiology of clinical conditions such as in-stent restenosis, vein bypass graft failure, and transplant vasculopathy, as well as aortic valve calcification. In the venous system, disturbed flow resulting from reflux, outflow obstruction, and/or stasis leads to venous inflammation and thrombosis, and hence the development of chronic venous diseases. Understanding of the effects of disturbed flow on ECs can provide mechanistic insights into the role of complex flow patterns in pathogenesis of vascular diseases and can help to elucidate the phenotypic and functional differences between quiescent (nonatherogenic/nonthrombogenic) and activated (atherogenic/thrombogenic) ECs. This review summarizes the current knowledge on the role of disturbed flow in EC physiology and pathophysiology, as well as its clinical implications. Such information can contribute to our understanding of the etiology of lesion development in vascular niches with disturbed flow and help to generate new approaches for therapeutic interventions.

Increased plasma xanthine oxidase activity is related to nuclear factor kappa beta activation and inflammatory markers in familial combined hyperlipidemia

BACKGROUND AND AIMS

Xanthine oxidase (XO) has been described as one of the major enzymes producing free radicals in blood. Oxidative stress and inflammatory processes have been implicated in the pathogenesis of endothelial dysfunction and the progression of atherosclerosis but until now, there is little data about the influence of vascular prooxidant systems and inflammation in familial combined hyperlipidemia (FCH). Our goal was to evaluate whether XO activity was altered in FCH and if it was related to the inflammatory process represented by NFkB, IL-6 and hsCRP, and assessing the correlation between XO activity and insulin resistance (IR).

METHOD AND RESULTS

40 Non-related subjects with FCH and 30 control subjects were included, all of them non-diabetic, normotensive and non-smokers. We measured lipid profile, glucose, insulin, uric acid, XO activity, malondialdehyde (MDA), IL-6 and hsCRP in plasma and NFkB activity in circulating mononuclear cells. Patients with FCH showed significantly higher levels of uric acid, XO activity, MDA, NFkB activity, IL-6 and hsCRP than controls. XO activity was independently related to NFkB activity with an odds ratio of 4.082; to IL-6 with an odds ratio of 4.191; and to IR with an odds ratio of 3.830. Furthermore, mean NFkB activity, IL-6 levels, and IR were highest in the highest percentile of XO activity.

CONCLUSIONS

Subjects with FCH showed increased XO and NFkB activities and low grade inflammatory markers related to atherosclerosis. XO activity was correlated with higher inflammatory activity and IR. These data could explain, in part, the high cardiovascular disease risk present in these patients.

Akt pathway is hypoactivated by synergistic actions of diabetes mellitus and hypercholesterolemia resulting in advanced coronary artery disease

Atherosclerosis is an inflammatory process leading to enhanced cellular proliferation, apoptosis, and vasa vasorum (VV) neovascularization. While both diabetes mellitus (DM) and hypercholesterolemia (HC) predispose to atherosclerosis, the precise interaction of these risk factors is unclear. Akt is a central node in signaling pathways important for inflammation, and we hypothesized that DM/HC would lead to aberrant Akt signaling and advanced, complex atherosclerosis. DM was induced in pigs by streptozotocin and HC by a high-fat diet. Animals were randomized to control (non-DM, non-HC), DM only, HC only, and DM/HC groups. Coronary artery homogenates were analyzed by immunoblotting for proteins involved in the Akt pathway, including phosphorylated (p)-Akt (Ser473), p-GSK-3beta (Ser9), activated NF-kappaB p65, and VEGF. Immunohistochemical staining for Ki67 (cell proliferation), terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) (apoptosis), and von Willebrand factor (vWF) (neovascularization) was performed. Neovascularization was visualized with micro-computerized tomography (CT). Only DM/HC animals developed advanced atherosclerosis and showed decreased p-Akt (Ser473) and p-GSK-3beta (Ser9) levels (P < 0.01 and P < 0.05, respectively). DM/HC arteries demonstrated increased cellular proliferation (P < 0.001), apoptosis (P < 0.01), and activation of NF-kappaB p65 (P < 0.05). Induction of DM/HC also resulted in significant VV neovascularization by enhanced VEGF expression (P < 0.05), increased vWF staining (P < 0.01), and increased density by micro-CT. In conclusion, DM and HC synergistically resulted in complex atherosclerosis associated with attenuated p-Akt (Ser473) levels. Aberrant Akt signaling correlated with increased inflammation, cellular proliferation, apoptosis, and VV neovascularization. Our results revealed a synergistic effect of DM and HC in triggering abnormal Akt signaling, resulting in advanced atherosclerosis.

Circulating mononuclear cells nuclear factor-kappa B activity, plasma xanthine oxidase, and low grade inflammatory markers in adult patients with familial hypercholesterolaemia

BACKGROUND

Few data are available on circulating mononuclear cells nuclear factor-kappa B (NF-kB) activity and plasma xanthine oxidase (XO) activity in heterozygous familial hypercholesterolaemia (FH). The goal of the study was to analyse circulating mononuclear cells NF-kB and plasma XO activities in FH patients.

MATERIALS AND METHODS

Thirty FH index patients and 30 normoglycaemic normocholesterolaemic controls matched by age, gender, body mass index, abdominal circumference and homeostasis model assessment index were studied. Plasma XO and inflammatory markers were measured by standard methods. NF-kB was assayed in circulating mononuclear cells.

RESULTS

Familial hypercholesterolaemia patients showed a significantly higher NF-kB (75.0 +/- 20.7 vs. 42.7 +/- 16.8 relative luminiscence units) and XO (0.44 +/- 0.13 vs. 0.32 +/- 0.09 mU mL(-1)) activities than controls. In addition, interleukin-1, interleukin-6, high sensitivity C reactive protein (hsCRP) and oxidized LDL (LDL-ox) were also significantly higher in FH patients. In the total group (FH and controls), XO was significantly associated with LDL-cholesterol (LDL-C), apolipoprotein B (apoB), NF-kB and hsCPR, and NF-kB activity was significantly associated with XO, hsCPR, LDL-ox, LDL-C and apoB plasma values. Using multiple regression analysis, XO was independently associated with hsCPR and NF-kB, and NF-kB activity in circulating mononuclear cells was independently associated with apoB and LDL-ox plasma values.

CONCLUSION

Familial hypercholesterolaemia patients show increased activities of NF-kB and XO, and higher values of low grade inflammatory markers related to atherosclerosis. NF-kB activity was independently associated with apoB plasma values. These data could explain in part the high cardiovascular disease risk present in these patients.

Metformin inhibits nuclear factor kappaB activation and decreases serum high-sensitivity C-reactive protein level in experimental atherogenesis of rabbits

Previous studies demonstrated that metformin has obvious antiatherogenic properties, but the exact mechanism remains unclear. Therefore, we established an atherosclerotic rabbit model in order to investigate the potential effects of metformin on transcription factor nuclear factor kappaB (NF-kappaB) and serum high-sensitivity C-reactive protein (hs-CRP) level, which had been regarded as proatherogenic factors. New Zealand rabbits were randomly divided into three groups: a control group (n = 8), an atherosclerotic group (AS group, n = 8), and a metformin treatment group (Met group, n = 8). The experimental atherosclerotic rabbit model was successfully established at the end of the 8th week. From the 9th week, rabbits in the Met group were administered with 150 mg/kg metformin daily by gavage. Blood samples were collected at days 0 and 8, and at 16 weeks to detect the level of blood lipid and serum glucose. At the end of the experiment, blood samples were withdrawn for determining serum hs-CRP. Aortic samples were harvested for histomorphometric analysis. Immunohistochemistry and Western blotting were used to detect the expression of NF-kappaB subunit p65 in nuclear extracts and phosphorylation of inhibitor of nuclear factor kappaB (IkappaB) in cytoplasmic extracts. An experimental atherosclerotic rabbit model was successfully established. The expression of nuclear NF-kappaB subunit p65 and cytoplasmic phosphorylation of IkappaB protein in the vessel wall was enhanced (P < 0.01, respectively) in the AS group, and serum hs-CRP level was significantly increased in the AS group compared with the control group (3.90 +/- 0.25 mg/l versus 1.36 +/- 0.14 mg/l, P < 0.01). Treatment with metformin significantly attenuated the progression of aortic atherosclerosis. In the Met group, there was a marked reduction in nuclear NF-kappaB subunit p65 and cytoplasmic phosphorylation of IkappaB protein expression (P < 0.01). Serum hs-CRP concentration was also significantly decreased (3.20 +/- 0.20 mg/l versus 3.90 +/- 0.25 mg/l, P < 0.05). Metformin inhibits the phosphorylation of IkappaB and the activation of NF-kappaB in the vessel wall of experimental atherogenesis of rabbits, as well as decreasing the serum level of hs-CRP, thus suggesting that metformin has vascular anti-inflammatory properties, which may be one of its antiatherogenic mechanisms.

The ubiquitin‐proteasome system—micro target for macro intervention?

The ubiquitin-proteasome system is the two sequential labeling and degradation system that accounts for the degradation of 80-90% of all intracellular proteins. Based on the diversity of its substrates, it is integrated in many different biological processes, especially inflammation and cell proliferation. Given the significance of these two processes for primary atherosclerosis and restenosis, the ubiquitin-proteasome system may be an amendable target in cardiovascular therapy. This review provides background information on the ubiquitin-proteasome system, currently available data on its involvement in cardiovascular diseases, and a future perspective on the targeted use proteasome inhibitors, including drug-eluting stents.

Dual Role of Oxidized LDL on the NF-KappaB Signaling Pathway

Atherosclerosis is a slowly evolutive age-linked disease of large arteries, characterized by a local lipid deposition associated with a chronic inflammatory response, leading potentially to acute plaque rupture, thrombosis and ischemic heart disease. Atherogenesis is a complex sequence of events associating first expression of adhesion molecules, recruitment of mononuclear cells to the endothelium, local activation of leukocytes and inflammation, lipid accumulation and foam cell formation. Low density lipoproteins (LDLs) become atherogenic after undergoing oxidation by vascular cells, that transform them into highly bioreactive oxidized LDL (oxidized LDLs). Oxidized LDLs are involved in foam cell formation, and trigger proatherogenic events such as overexpression of adhesion molecules, chemoattractant agents growth factors and cytokines involved in the inflammatory process, cell proliferation and apoptosis. Moreover, this toxic effect of oxidized LDLs plays probably a role in plaque erosion/rupture and subsequent atherothrombosis. Several biological effects of oxidized LDLs are mediated through changes in the activity of transcription factors and subsequently in gene expression. Oxidized LDLs exert a biphasic effect on the redox-sensitive transcription factor NF-kappaB, which can be activated thereby up-regulating proinflammatory gene expression, such as adhesion molecules, tissue factor, scavenger receptor LOX-1. On the other hand, higher concentrations of oxidized LDLs may inhibit NF-kappaB activation triggered by inflammatory agents such as LPS, and may thereby exert an immunosuppressive effect. This review is an attempt to clarify the mechanism by which oxidized LDLs may up- or down-regulate NF-kappaB, the role of NF-kappaB activation (or inhibition), and the consequences of the oxidized LDLs-mediated NF-kappaB dysregulation and their potential involvement in atherosclerosis.

AGEs increased migration and inflammatory responses of adventitial fibroblasts via RAGE, MAPK and NF-kappaB pathways

OBJECTIVE

Advanced glycation end products (AGEs) and vascular adventitial fibroblasts (AFs) are involved in diabetes-related vascular complications. However, the effect of AGEs on AFs remains unclear. The aim of this study was to observe the impact of AGEs on cell migration capacity and associated inflammatory responses of AFs.

METHODS AND RESULTS

Isolated vascular AFs of Sprague-Dawley rats were cultured, harvested after 24h synchronization and challenged with AGE-HSA. AGE-HSA upregulated the expression of receptor for advanced glycation end products (RAGE), significantly increased the migration capacity and inflammatory mediators MCP-1, IL-6, VCAM-1 expressions on AFs. These effects could be significantly attenuated by anti-RAGE neutralizing antibody, p38, ERK1/2 and JNK MAPK inhibitors as well as by candesartan. AGE-HAS also upregulated NF-kappaB transcriptional activity and I-kappaB-alpha phosphorylation, effect that was significantly inhibited by candesartan.

CONCLUSIONS

AGE-HSA increased the migration capacity and inflammatory responses of rat AFs via RAGE-MAPK-NF-kappaB pathways. Candesartan effectively inhibited these effects which might be a novel vascular protection mechanism of candesartan.

Induction of MIF expression by oxidized LDL via activation of NF-kappaB in vascular smooth muscle cells

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine playing important roles in atherosclerosis. MIF gene deficiency and neutralizing antibodies against MIF have been reported to exert anti-atherosclerotic effects in various animal models. However, the mechanism by which MIF is induced in atherosclerotic lesions remains unclear. In the present studies, we cloned a 540bp full-length rabbit MIF cDNA by screening a rabbit uterine library. The cDNA contains a 348bp open-reading frame which encodes a deduced 115-amino acid polypeptide with approximately 90% similarity to human and mouse homologs. Constitutive MIF mRNA expression was detected in most rabbit tissues including aortas. The expression of MIF obviously abounded in vascular smooth muscle cells (VSMCs) of the atherosclerotic plaques. In cultured VSMCs, MIF expression was significantly induced by a pro-atherogenic factor, oxidized low-density lipoprotein (oxLDL). Promoter analysis showed there were two NF-kappaB binding sites in the MIF proximal promoter region. Deletion or mutation of the two sites abolished oxLDL-enhanced MIF promoter activity. Moreover, the induction of MIF by oxLDL can be blocked by IkappaB-alpha overexpression. Taken together, our results revealed that MIF expression can be induced by oxLDL in VSMCs via a NF-kappaB dependent manner, which may contribute to the pathogenesis of atherosclerosis.

Prevention of vasa vasorum neovascularization attenuates early neointima formation in experimental hypercholesterolemia

Vasa vasorum (VV) neovascularization is a key feature of early atherosclerosis and adds substantial endothelial exchange-surface to the coronary vessel wall. Thus, it is conceivable that VV neovascularization favors the entry of pro-inflammatory and pro-atherosclerotic blood components into the coronary vessel wall. We sought to investigate the effects of Thalidomide (Th), a potent anti-angiogenic drug on vasa vasorum (VV) neovascularization, vessel wall inflammation, and neointima formation in early experimental atherosclerosis. Female domestic swine, 3 months old, were fed normal (N, n = 12) or high-cholesterol diet (HC, n = 12) for 3 months. In each group six pigs were randomized to 200 mg Thalidomide daily for the diet period (N + Th, HC + Th). LADs were scanned with micro-CT (20 microm cubic voxel size) to determine VV spatial density (#/mm2). Fresh-frozen coronary tissue was used for western blotting (VEGF, TNF-alpha, LOX-1, Ikappabetaalpha and Gro-alpha) and electrophoretic mobility shift assay (EMSA, NFkappabeta). Treatment with Thalidomide preserved VV spatial density [2.7 +/- 0.3 (N), 6.4 +/- 0.7 (HC), 3.5 +/- 0.8 (HC + Th); p = ns HC + Th vs. N] and inhibited the expression of VEGF, TNF-alpha and LOX-1, but not NFkappabeta activity in the coronary vessel wall. Immunofluorescence analyses revealed co-localization of vWF but not SMA and NFkappabeta, TNF-alpha as well as VEGF in HC and HC + Th coronaries. Intima-media thickness was significantly inhibited in HC + Th compared to HC. Serum levels of hs-CRP and TNF-alpha did not differ among the groups. Our study supports a role of VV neovascularization in the development of and a therapeutic potential for anti-angiogenic intervention in early atherosclerosis.

Low vasa vasorum densities correlate with inflammation and subintimal thickening: potential role in location--determination of atherogenesis

OBJECTIVES

To assess the role of coronary vasa vasorum (VV) spatial distribution in determining the location of early atherosclerotic lesion development.

METHODS AND RESULTS

Six, 3-month-old, female, crossbred swine were fed 2% high-cholesterol (HC) diet for 3 months prior to euthanasia. Six other pigs were fed normal diet (N) for the entire 6 months. Right coronary arteries were harvested and scanned intact with micro-CT (20mum cubic-voxel-size). After scanning, randomly selected cross-sectional histological sections were stained for nuclear-factor kappaB (NF-kappaB), hypoxia-inducible factor-1alpha (HIF-1alpha), macrophages, von-Willebrand-factor, dihydroethidium (DHE), tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). The number of positive stained cells, as well as intima-to-media ratio, were compared with VV density (#/mm(2)) obtained from micro-CT images (which closely matched the location of the histological sections) in each of four equal quadrants of the coronary vessel wall. In normal, as well as HC pigs, the number of NF-kappaB (r=0.73 and 0.70), HIF-1alpha (r=0.74 and 0.77), TNF-alpha (r=0.58 and 0.72) and IL-6 (r=0.70 and 0.72) positive cells as well as the expression of DHE (Kendall tau coefficient -0.64 and -0.63) inversely correlated with VV density. In HC the VV density also inversely correlated with intima/media ratios (r=0.65).

CONCLUSIONS

Our data suggest that low VV density territories within the coronary vessel wall are susceptible to hypoxia, oxidative stress and microinflammation and may therefore be starting points of early atherogenesis.

The integrin alpha2beta1 agonist, aggretin, promotes proliferation and migration of VSMC through NF-kB translocation and PDGF production

BACKGROUND AND PURPOSE

During the development of atherosclerotic plaques, vascular smooth muscle cells (VSMCs) migrate from the media to the intima through the basement membrane and interstitial collagenous matrix, and proliferate to form neointima. Here, we investigate the mechanism of VSMC migration and proliferation caused by aggretin, a snake venom integrin alpha2beta1 agonist.

EXPERIMENTAL APPROACH

Cultures of rat and human VSMCs were treated with aggretin and the signal transduction pathways induced by this agonist were examined by Western blotting, immunoprecipitation and electrophoretic mobility shift assay techniques.

KEY RESULTS

Aggretin-induced VSMC proliferation was blocked by a monoclonal antibody (mAb) against integrin alpha2 (AII2E10) or against the platelet-derived growth factor receptor (PDGFR)-beta. Proliferation was also blocked by inhibition of the tyrosine kinase Src with PP2, phospholipase C (PLC) with U73122, extracellular signal-regulated kinase (ERK) with PD98059 or nuclear factor-kappa B (NF-kB) activation with pyrrolidine dithiocarbamate (PDTC). VSMC migration towards immobilized aggretin was increased in a modified Boyden chamber and this effect was blocked by alpha2beta1-Src-PLC-MAPK axis inhibitors, but not by PDTC, PDGFR-beta mAb, or a phosphoinositide-3 kinase inhibitor, LY294002. Aggretin stimulated the phosphorylation of PDGFR-beta, Src and ERK in a time-dependent manner. NF-kB translocation and platelet-derived growth factor (PDGF)-BB production were also observed. The ERK activation, NF-kB translocation and PDGF-BB production were blocked by PP2, U73122 and PD98059.

CONCLUSIONS AND IMPLICATIONS

Aggretin induces VSMC proliferation and migration mainly through binding to integrin alpha2beta1, and subsequently activates Src, PLC and ERK pathways, inducing NF-kB activation and PDGF production.

Expression of ubiquitin in peripheral inflammatory cells from patients with coronary artery disease

In addition to its role in the removal of damaged and unneeded proteins, the ubiquitin-proteasome system (UPS) may play a key role in coronary artery disease (CAD). To investigate the expression of ubiquitin in monocytes and lymphocytes isolated from patients at different stages of CAD, 120 patients with CAD (40 with acute myocardial infarction [AMI], 40 with unstable angina pectoris [UAP] and 40 with stable angina pectoris [SAP]) were selected; 40 patients with normal coronary arteries served as controls. At both the mRNA and protein levels, ubiquitin expression was higher in patients with CAD than in controls, and patients with AMI had a much higher expression of ubiquitin (at both the mRNA and protein levels) than those with SAP and UAP. These data indicate that ubiquitin expression increased with increasing severity of CAD, suggesting that ubiquitin may play a critical role in the development and progression of CAD.

Expression of heme oxygenase-1, hypoxia inducible factor-1α, and ubiquitin in peripheral inflammatory cells from patients with coronary heart disease

: The increased expression of heme oxygenase-1 content, a stress-response protein, directly correlates with the incidence of coronary heart disease. Down-regulation of hypoxia inducible factor-1α activity, a major downstream effector of the signaling pathways activated by hypoxia, increases cell survival after hypoxia. The ubiquitin system, a non-lysosomal pathway of protein degradation, is involved in processes of coronary heart disease. The aim of this study was to investigate the expression of heme oxygenase-1, hypoxia inducible factor-1α, and ubiquitin in both monocytes and lymphocytes isolated from patients at the mRNA and protein levels in different stages of coronary heart disease and their possible correlation.

: A total of 90 patients with coronary heart disease (30 acute myocardial infarction, 30 unstable angina pectoris, and 30 stable angina pectoris) were selected, and 30 cases with normal coronary artery served as controls. The mRNA and protein expression of heme oxygenase-1, hypoxia inducible factor-1α, and ubiquitin in monocytes and lymphocytes were examined by semi-quantitative reverse transcriptase polymerase chain reaction and Western blotting, respectively.

: The mRNA expression of heme oxygenase-1 and ubiquitin was associated with the severity of coronary heart disease (p<0.05). There was no significant difference in hypoxia inducible factor-1α mRNA expression between the coronary heart disease patients and controls. The protein expression of heme oxygenase-1, hypoxia inducible factor-1α, and ubiquitin was significantly stronger in patients with coronary heart disease than in controls, and the expression levels increased with the severity of the disease. There was a positive association between heme oxygenase-1 and hypoxia inducible factor-1α and ubiquitin, antioxidative therapy with adrenergic receptor blocker, angiotensin-converting enzyme inhibitor or statins up-regulated the expression of heme oxygenase-1 and hypoxia inducible factor-1α.

: These data suggest that heme oxygenase-1, hypoxia inducible factor-1α, and ubiquitin are involved in the development and progression of coronary heart disease and thus may be useful biomarkers for coronary heart disease.

Clin Chem Lab Med 2009;47:327–33.

Bamboo culm extract supplementation elevates HDL-cholesterol and ameliorates oxidative stress in C57BL/6 mice fed atherogenic diet

Previously, we reported that bamboo culms possess a stronger antioxidative capacity than bamboo leaves in vitro. In this study, we investigated whether bamboo culm extract (BCE) supplementation ameliorates oxidative stress and hepatic nuclear factor kappaB (NF kappa B) activation in C57BL/6 mice fed an atherogenic diet. In addition, the effect of BCE supplementation on plasma lipid levels of the animals was tested. The mice were randomly assigned to a normal diet, an atherogenic diet (control), or an atherogenic diet supplemented with 1% (wt/wt) BCE or 3% (wt/wt) BCE for 16 weeks. Atherogenic diet-induced oxidative stress, measured by hepatic thiobarbituric acid-reactive substances and protein carbonyls, was significantly lower in the BCE-supplemented groups than in the control (P < .05). Total antioxidative capacity was elevated in the BCE groups, along with greater activities of antioxidative enzymes such as superoxide dismutase and catalase, compared to the control or normal groups (P < .05). The hepatic NF kappa B binding activities were significantly lower in the BCE groups as well (P < .05). The high-density lipoprotein-cholesterol level was significantly elevated by BCE supplementation (P < .05), whereas the effects of BCE on triglyceride and total cholesterol were inconsistent. Results from this study suggest that BCE supplementation may lessen oxidative stress via a series of changes, including a reinforced antioxidant system, and also suggest that the lowered oxidative stress status may down-regulate the activation of inflammatory mediators.

Microcirculation and oxidative stress

The microcirculation is a complex and integrated system, transporting oxygen and nutrients to the cells. The key component of this system is the endothelium, contributing to the local balance between pro and anti-inflammatory mediators, hemostatic balance, as well as vascular permeability and cell proliferation. A constant shear stress maintains vascular endothelium homeostasis while perturbed shear stress leads to changes in secretion of vasodilator and vasoconstrictor agents. Increased oxidative stress is a major pathogenetic mechanism of endothelial dysfunction by decreasing NO bioavailability, promoting inflammation and participating in activation of intracellular signals cascade, so influencing ion channels activation, signal transduction pathways, cytoskeleton remodelling, intercellular communication and ultimately gene expression. Targeting the microvascular inflammation and oxidative stress is a fascinating approach for novel therapies in order to decrease morbidity and mortality of chronic and acute diseases.