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Objective: Vascular endothelial cells (ECs) normally maintain vascular homeostasis and are regulated by proinflammatory cytokines and reactive oxygen species. A human genome-wide association study identified that AIP1 (ASK1 [apoptosis signal-regulating kinase 1]-interacting protein-1; also identified as DAB2IP ) gene variants confer susceptibility to cardiovascular disease, but the underlying mechanism is unknown. Approach and Results: We detected a normal AIP1 form (named AIP1A) in the healthy aorta, but a shorter form of AIP1 (named AIP1B) was found in diseased aortae that contained atherosclerotic plaques and graft arteriosclerosis. AIP1B transcription in resting ECs was suppressed through epigenetic inhibition by RIF1 (Rap1 [ras-related protein 1]-interacting factor 1)/H3K9 (histone H3 lysine 9) methyltransferase-mediated H3K9 trimethylation, and this inhibition was released by proinflammatory cytokines. AIP1A, but not AIP1B, was downregulated by proteolytic degradation through a Smurf1 (SMAD [suppressor of mothers against decapentaplegic miscellaneous] ubiquitylation regulatory factor 1)-dependent pathway in ECs under inflammation. Therefore, AIP1B was the major form present during inflammatory conditions. AIP1B, which lacks the N-terminal pleckstrin homology domain of AIP1A, localized to the mitochondria and augmented TNFα (tumor necrosis factor alpha)-induced mitochondrial reactive oxygen species generation and EC activation. AIP1B-ECTG (EC-specific AIP1B transgenic) mice exhibited augmented reactive oxygen species production, EC activation, and neointima formation in vascular remodeling models., Conclusions: Our current study suggests that a shift from anti-inflammatory AIP1A to proinflammatory AIP1B during chronic inflammation plays a key role in inflammatory vascular diseases.

Data from clinical research and our previous study have suggested the potential involvement of SENP1, the major protease of post-translational SUMOylation, in cardiovascular disorders. Here, we investigate the role of SENP1-mediated SUMOylation in graft arteriosclerosis (GA), the major cause of allograft failure. We observe an endothelial-specific induction of SENP1 and GATA2 in clinical graft rejection specimens that show endothelial activation-mediated vascular remodelling. In mouse aorta transplantation GA models, endothelial-specific SENP1 knockout grafts demonstrate limited neointima formation with attenuated leukocyte recruitment, resulting from diminished induction of adhesion molecules in the graft endothelium due to increased GATA2 SUMOylation. Mechanistically, inflammation-induced SENP1 promotes the deSUMOylation of GATA2 and IκBα in endothelial cells, resulting in increased GATA2 stability, promoter-binding capability and NF-κB activity, which leads to augmented endothelial activation and inflammation. Therefore, upon inflammation, endothelial SENP1-mediated SUMOylation drives GA by regulating the synergistic effect of GATA2 and NF-κB and consequent endothelial dysfunction.

There is considerable global demand for three-dimensional (3D) functional tissues which mimic our native organs and tissues for use as in vitro drug screening systems and in regenerative medicine. In particular, there has been an increasing number of patients who suffer from arterial diseases such as arteriosclerosis. As such, in vitro 3D arterial wall models that can evaluate the effects of novel medicines and a novel artificial graft for the treatment are required. In our previous study, we reported the rapid construction of 3D tissues by employing a layer-by-layer (LbL) technique and revealed their potential applications in the pharmaceutical fields and tissue engineering. In this study, we successfully constructed a 3D arterial wall model containing vasa vasorum by employing a LbL technique for the first time. The cells were coated with extracellular matrix nanofilms and seeded into a culture insert using a cell accumulation method. This model had a three-layered hierarchical structure: a fibroblast layer, a smooth muscle layer, and an endothelial layer, which resembled the native arterial wall. Our method could introduce vasa vasorum into a fibroblast layer in vitro and the 3D arterial wall model showed barrier function which was evaluated by immunostaining and transendothelial electrical resistance measurement. Furthermore, electron microscopy observations revealed that the vasa vasorum was composed of single-layered endothelial cells, and the endothelial tubes were surrounded by the basal lamina, which are known to promote maturation and stabilization in native blood capillaries. These models should be useful for tissue engineering, regenerative medicine, and pharmaceutical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 814-823, 2017., (© 2016 Wiley Periodicals, Inc.)

Emerging evidence suggests that dipeptidyl peptidase-4 (DPP-4) inhibitors, including sitagliptin, exert favourable effects on the vascular endothelium. DPP-4 inhibitors suppress the degradation of glucagon-like peptide-1 (GLP‑1), which has been reported to enhance nitric oxide (NO) production. However, the effects of DPP-4 inhibitors on endothelin-1 (ET-1) expression in the aorta, as well as the underlying mechanisms responsible for these effects, have yet to be investigated in animal models of diabetes mellitus (DM). In the present study, the rats were randomly divided into the following four groups: i) control; ii) DM; iii) DM + low‑dose sitagliptin (10 mg/kg); and iv) DM + high‑dose sitagliptin (30 mg/kg). Apart from the control group, all the rats received a high-fat diet for 8 weeks prior to the induction of diabetes with an intraperitoneal injection of streptozotocin. The treatments were then administered for 12 weeks. The serum levels of ET-1, NO, GLP-1 and insulin were measured as well as endothelial function. The expression of ET-1, AMP-activated protein kinase (AMPK) and nuclear factor (NF)-κB/IκBα were determined. After 12 weeks of treatment, the diabetic rats receiving sitagliptin showed significantly elevated serum levels of GLP-1 and NO, and reduced levels of ET-1. Moreover, sitagliptin significantly attenuated endothelial dysfunction as well as the remodeling of the aortic wall. Notably, sitagliptin inhibited ET-1 expression at the transcriptional and translational level in the aorta, which may have been mediated by the suppression of the NF-κB/IκBα system induced by AMPK activation. The majority of the above-mentioned effects were dose dependent. Taken together, the findings of the present study indicate that sitagliptin inhibits ET-1 expression in the aortic endothelium by suppressing the NF-κB/IκBα system through the activation of the AMPK pathway in diabetic rats. These findings further demonstrate some of the vasoprotective properties of DPP-4 inhibitors in vivo.

Endothelial cells (ECs) apoptosis is an initial event in transplant arteriosclerosis (TA), resulting in allograft function loss. To elucidate the precise mechanisms of ECs apoptosis leading to neointimal smooth muscle cells (SMCs) accumulation during TA. We induced apoptosis in cultured ECs by overexpressing p53 through lentivirus-mediated transfection. ECs apoptosis induced the production of transforming growth factor (TGF)-β1 in both apoptotic and neighboring viable cells, leading to increased TGF-β1 in the culture media. Conditioned media from Ltv-p53-transfected ECs further promoted transition of cultured ECs to SM-like cells by activating TGF-β/Smad3, PI3K/Akt/mTOR, and MAPK/ERK signaling in a TGF-β-dependent manner. In transgenic rat aorta transplantation models, inhibition of ECs apoptosis in Bcl-xL(+/+) knock-in rat aortic allografts significantly reduced TGF-β1 production both in allograft endothelia and in blood plasma, which in turn decreased accumulation of SM22α+ cells from transgenic recipient ECs originally marked with EGFP knock-in in neointima and alleviated TA. Systemic treatment with SIS3, AP23573, or PD98059 also prevented recipient ECs-originated SM-like cells accumulation and intima hyperplasia in aortic allografts. These data suggest that allograft EC apoptosis induced recipient endothelial-mesenchymal (smooth muscle) transition via TGF-β signaling, resulting in recipient EC-derived SMC accumulation as a major mechanism of vascular remodeling during TA., (© Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.)

The endothelial cells (ECs) lining of a blood vessel wall are exposed to both the wall shear stress (WSS) of blood flow and the circumferential strain (CS) of pulsing artery wall motion. Both WSS and CS keep involved in the modulation of ECs' biochemical response and function and the temporal phase angle between the two is called stress phase angle (SPA). Previous studies at the cellular level have indicated that SPA is highly negative at sites that are prone to atherosclerosis, and hypothesized that large SPA may contribute to atherogenesis. Till now, there is no experimental data to support this hypothesis, probably due to the lack of a proper tool for measuring WSS and CS simultaneously and real time. In this study, a non-invasive ultrasonic biomechanics method was utilized to quantitatively calculate the SPA and experimentally evaluate the role of SPA in predicting early atherosclerosis. Three silicon tubes with a stiffness of 1.15, 3.62, 9.38 MPa were assembled in a pulsatile flow circuit and the values of SPA were measured to be -101.86 ± 3.65°,-170.19 ± 17.77° and -260.63 ± 18.62°, respectively. For the PVA-c phantoms, stiffness was 162.45, 235.68 and 374.24 kPa, the SPA corresponding to -170.32 ± 17.55°,-207.56 ± 10.78° and -261.08 ± 10.90°, respectively. Both phantom studies results demonstrated that SPA was highly negative in stiffer arteries. Further, experiments were taken in healthy living rats as control group (n = 3), atherosclerotic model group (n = 3), and drug treated group (n = 3), and the results showed that SPA was most negative in the model group, and SPA was least negative in the control group. Together, this study suggested that highly negative SPA appeared to be a prominent mechanical feature of vessels prone to atherosclerotic disease.

Vascular rejection that leads to transplant arteriosclerosis (TA) is the leading representation of chronic heart transplant failure. In TA, the immune system of the recipient causes damage of the arterial wall and dysfunction of endothelial cells and smooth muscle cells. This triggers a pathological repair response that is characterized by intimal thickening and luminal occlusion. Understanding the mechanisms by which the immune system causes vasculature rejection and TA may inform the development of novel ways to manage graft failure. Here, we describe a mouse aortic interposition model that can be used to study the pathogenic mechanisms of vascular rejection and TA. The model involves grafting of an aortic segment from a donor animal into an allogeneic recipient. Rejection of the artery segment involves alloimmune reactions and results in arterial changes that resemble vascular rejection. The basic technical approach we describe can be used with different mouse strains and targeted interventions to answer specific questions related to vascular rejection and TA.

Objectives: The aim of this study was to determine the role of suppressor of cytokine signaling 1 (SOCS1) in graft arteriosclerosis (GA)., Background: GA, the major cause of late cardiac allograft failure, is initiated by immune-mediated endothelial activation resulting in vascular inflammation and consequent neointima formation. SOCS1, a negative regulator of cytokine signaling, is highly expressed in endothelial cells (ECs) and may prevent endothelial inflammatory responses and phenotypic activation., Methods: Clinical specimens of coronary arteries with GA, with atherosclerosis, or without disease were collected for histological analysis. SOCS1 knockout or vascular endothelial SOCS1 (VESOCS1) transgenic mice were used in an aorta transplant model of GA. Mouse aortic ECs were isolated for in vitro assays., Results: Dramatic but specific reduction of endothelial SOCS1 was observed in human GA and atherosclerosis specimens, which suggested the importance of SOCS1 in maintaining normal endothelial function. SOCS1 deletion in mice resulted in basal EC dysfunction. After transplantation, SOCS1-deficient aortic grafts augmented leukocyte recruitment and neointima formation, whereas endothelial overexpression of SOCS1 diminished arterial rejection. Induction of endothelial adhesion molecules in early stages of GA was suppressed by the VESOCS1 transgene, and this effect was confirmed in cultured aortic ECs. Moreover, VESOCS1 maintained better vascular function during GA progression. Mechanistically, endothelial SOCS1, by modulating both basal and cytokine-induced expression of the adhesion molecules platelet/endothelial cell adhesion molecule-1, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, restrained leukocyte adhesion and transendothelial migration during inflammatory cell infiltration., Conclusions: SOCS1 prevents GA progression by preserving endothelial function and attenuating cytokine-induced adhesion molecule expression in vascular endothelium., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Revealing the mechanisms underlying the functional integrity of the vascular system could make available novel therapeutic approaches. We previously showed that knocking out the widely expressed peptide adrenomedullin (AM) or receptor activity-modifying protein 2 (RAMP2), an AM-receptor accessory protein, causes vascular abnormalities and is embryonically lethal. Our aim was to investigate the function of the vascular AM-RAMP2 system directly., Methods and Results: We generated endothelial cell-specific RAMP2 and AM knockout mice (E-RAMP2(-/-) and E-AM(-/-)). Most E-RAMP2(-/-) mice died perinatally. In surviving adults, vasculitis occurred spontaneously. With aging, E-RAMP2(-/-) mice showed severe organ fibrosis with marked oxidative stress and accelerated vascular senescence. Later, liver cirrhosis, cardiac fibrosis, and hydronephrosis developed. We next used a line of drug-inducible E-RAMP2(-/-) mice (DI-E-RAMP2(-/-)) to induce RAMP2 deletion in adults, which enabled us to analyze the initial causes of the aforementioned vascular and organ damage. Early after the induction, pronounced edema with enhanced vascular leakage occurred. In vitro analysis revealed the vascular leakage to be caused by actin disarrangement and detachment of endothelial cells. We found that the AM-RAMP2 system regulates the Rac1-GTP/RhoA-GTP ratio and cortical actin formation and that a defect in this system causes the disruption of actin formation, leading to vascular and organ damage at the chronic stage after the gene deletion., Conclusions: Our findings show that the AM-RAMP2 system is a key determinant of vascular integrity and homeostasis from prenatal stages through adulthood. Furthermore, our models demonstrate how endothelial cells regulate vascular integrity and how their dysregulation leads to organ damage.

To portray the chronic inflammation in atherosclerosis, leukocytic cell types involved in the immune response to invading pathogens are often the focus. However, atherogenesis is a complex pathological deterioration of the arterial walls, where vascular cell types are participants with regards to deterioration and disease. Since other recent reviews have detailed the role of both the innate and adaptive immune response in atherosclerosis, herein we will summarize the latest developments regarding the association of bacteria with vascular cell types: infections as a risk factor for atherosclerosis; bacterial invasion of vascular cell types; the atherogenic sequelae of bacterial presence such as endothelial activation and blood clotting; and the identification of the species that are able to colonize this niche. The evidence of a polybacterial infectious component of the atheromatous lesions opens the doors for exploration of the new field of vascular infectology and for the study of atherosclerosis microbiome.

Background/objective: It is known that menopause or lack of endogenous estrogen is a risk factor for endothelial dysfunction and CAD. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is involved inmultiple phases of vascular dysfunction. The purpose of the current study was to determine the association between soluble LOX-1 (sLOX-1) and pregnancy followed by delivery in women of reproductive age., Materials/methods: Sixty-eight subjects with pregnancy followed by delivery (group 1) and 57 subjects with nongravidity (group 2) were included in this study. Levels of sLOX-1 were measured in serum by EL SA., Results: Plasma levels of sLOX-1 were significantly lower in Group 1 than Group 2 in women of reproductive age (0.52 ± 0.18 ng/mL and 0.78 ± 0.13, resp., P < 0.001). There were strong correlations between sLOX-1 levels and the number of gravida (r = -0.645, P < 0.001). The levels of sLOX-1 highly correlated with the number of parous (r = -0.683, P < 0.001)., Conclusion: Our study demonstrated that serum sLOX-1 levels were associated with pregnancy followed by delivery that might predict endothelial dysfunction. We conclude that pregnancy followed by delivery may delay the beginning and progress of arteriosclerosis and its clinical manifestations in women of reproductive age.

Purpose of Review: Atherosclerotic lesion vulnerability leading to plaque rupture is a major cause of morbidity in western society. Although several recent major trials have identified statins and angiotensin-converting enzyme inhibitors as having a pleiotropic benefit, no current therapeutic regime directly targets atherosclerosis. The emerging functions of microRNAs (miRs) in regulating gene expression have opened diverse possibilities in understanding plaque biology and in offering new therapeutic strategies. In this review, we consider vascular endothelial cells, smooth muscle cells and monocytes as the main cellular participants in vessel homeostasis during atherosclerosis evolution and discuss how they are functionally modified by miRs and how these modifications may allow therapeutic targeting., Recent Findings: Emerging roles for miRs in the pro-inflammatory functions of monocytes and macrophages, and proangiogenic functions of endothelial cells, suggest that miRs regulating these processes are potential targets. Conversely, the contribution of smooth muscle cells to plaque integrity may be augmented by miR-based agents. Recent investigations have uncovered key roles for miRs in each of these areas, which may be targeted through either silencing of proatherogenic or augmentation of antiatherogenic pathways., Summary: With emerging miR-based therapeutics, a new paradigm for therapeutic intervention with the ultimate goal of plaque stabilization may exist.

Neovascularization of atherosclerotic lesions favors their progression toward rupture. Despite this pathophysiological importance, data regarding the mechanism(s) initiating plaque neovascularization are scarce. Recent findings indicate that smooth muscle cells located underneath early aortic atheromatous lesions display a pro-angiogenic phenotype, and that lipid mediators derived from these lesions are potent inducers of this phenotypic change. Here, we discuss these new data suggesting that smooth muscle cells could be the central organizers of an angiogenic response initiated by the very first cause of the atheromatous disease, the accumulation and retention of lipids in the arterial wall., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Hypertension is a known risk factor for arteriosclerosis, and causes both atherosclero= sis of medium-large arteries and arteriolosclerosis of the arterioles. Elevated blood pressure causes damage to the endothelium and vascular wall through both mechanical and humoral factors. We and others have shown that inhibition of the renin-angiotensin system at a 'critical period' during the development of hypertension results in a permanent suppression of hypertension in animal models. We have also reported that high-dose renin-angiotensin inhibition results in regression of hypertension, possibly by regression of renal arteriolar hypertrophy. These results suggest that understanding the process of arterial remodeling may play a key role in the development of new strategies for prevention and regression of hypertension and arteriosclerosis.

Atherosclerosis is a chronic inflammatory disease of the arterial wall; during the transition from primitive fatty streaks to more complex lesions, smooth muscle cells play a pivotal role. According to the canonical view, smooth muscle cells migrate from tunica media and contribute to the development of neointima and the fibrous cap. New evidences suggest that bone marrow-derived smooth muscle progenitors might contribute to both neointima formation and fibrous cap development. In this review, we discuss the controversial identity and origin of circulating smooth muscle progenitors by focusing on the methodological clues for their isolation. Furthermore, we examine the potential contribution of smooth muscle progenitors in the development/progression of atherosclerotic lesions., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Background: Cardiac transplant arteriosclerosis or cardiac allograft vasculopathy remains the leading cause of graft failure and patient death in heart transplant recipients. Endothelial cell injury is crucial in the development of human atherosclerosis and may play a role in allograft vasculopathy. Glutathione-S-transferase (GST) is known to protect endothelial cells from damage by oxidants and toxins. However, the contribution of human GST A4-4 (hGSTA4-4) to vascular cell injury and consequent transplant arteriosclerosis is unknown., Methods: A recombinant adenoviral vector containing hGSTA4-4 gene was constructed and delivered to vascular endothelial cells in an in vivo rabbit carotid artery transplant model. Forty-five days after transplantation, allografts were harvested (n=28). Blood flow was measured by ultrasonography. In addition, grafts were analyzed by histology, morphometry, immunostaining, and western blot., Results: The severity of arteriosclerosis in hGSTA4-4 transduced allografts was compared with control by measuring degree of stenosis by neointima. Decrease in blood flow in hGSTA4-4 transduced allografts was significantly less than control allografts, which also developed greater intimal thickening and stenosis than hGSTA4-4 transduced allografts in the proximal and distal regions of the graft. Leukocyte and macrophage infiltration was reduced in hGSTA4-4 transduced carotid arteries., Conclusion: Our data indicate that hGSTA4-4 overexpression protects the integrity of vessel wall from oxidative injury, and attenuates transplant arteriosclerosis.

This study aims to explore the interactive effect of vital exhaustion (VE) and endothelial dysfunction on preclinical atherosclerosis, assessed by carotid intima-media thickness (IMT). Furthermore, interaction between VE and carotid elasticity is examined. Participants were 1,596 young healthy adults from the Cardiovascular Risk in Young Finns study. Endothelial dysfunction was measured by brachial flow-mediated dilatation (FMD), and carotid elasticity by carotid artery compliance (CAC). Significant interactions between FMD and VE, and between CAC and VE, for IMT were found in participants with the very lowest FMD and CAC. Thus, VE may be harmful if the endothelium is not working properly.

Background/methods: Coating a silica surface with the isolated lipoprotein receptor heparan sulfate proteoglycan (HS-PG) from arterial endothelium and vascular matrices, we could observe the very earliest stages of arteriosclerotic plaque development by ellipsometric techniques in vitro (patent EP 0 946 876). This so-called nanoplaque formation is represented by the ternary aggregational complex of the HS-PG receptor, lipoprotein particles and calcium ions. The model was validated in several clinical studies on statins in cardiovascular high-risk patients applying their native blood lipoprotein fractions., Results: In 7 patients who had undergone a valvular defect operation, the reduction of arteriosclerotic nanoplaque formation in normal Krebs solution amounted to 6.1 +/- 2.3% (p < 0.0156) and of nanoplaque size to 37.5 +/- 13.2% (p < 0.0312), respectively, after a 3-month therapy with n-3 fatty acids (3 ..3 g daily, Ameu 500 mg). Additionally, the quotient oxLDL/LDL was lowered by 6.8 +/- 2.1% (p < 0.0166), the MDA concentration remained unchanged and the lipoprotein(a) concentration decreased by 15.8 +/- 5.6% (p < 0.0469) in the patients' blood. The concentration of the nanoplaque promoting particles VLDL and total triglycerides was diminished by 34.1 +/- 11.6% (p < 0.0469) and 26.7 +/- 10.8% (p < 0.0156), respectively. Furthermore, the ratio of the strongly atherogenic small dense to the total LDL cholesterol (LDL5+LDL6)/LDLtot decreased by 9.9 +/- 3.0% (p < 0.0174)., Conclusions: A combinatorial regression analysis revealed a basis for a mechanistic explanation of nanoplaque reduction under n-3 fatty acid treatment. This effect was possibly due to the beneficial changes in lipid concentrations and an attenuation of the risk factors oxLDL/LDL and (LDL5+LDL6)/LDLtot., (Copyright 2009 S. Karger AG, Basel.)

Arterial ageing - arteriosclerosis - is characterised by both thickening and stiffening of the walls of large and medium arteries. The molecular and cellular mechanisms (i.e. endothelial dysfunction, matrix remodelling, ...) involved in this process are complex, and at least in part common to atherosclerotic injury. Arterial stiffness is strongly associated with cardiovascular disease and an increased risk of morbidity and mortality. The aim of this review is to provide an update on the pathophysiology and the biological process of arterial ageing and to underline the main difference with atherosclerosis damage process in particularly during the calcification step.

Apolipoprotein (apo) A-I(Milano) is an apo A-I mutant characterized by a cysteine for arginine substitution at position 173. Apo A-I(Milano) carriers have much less atherosclerosis than expected from their low plasma high-density lipoprotein cholesterol levels, suggesting that this mutant may have superior atheroprotective properties. Here, we compare the effect of hepatocyte-directed gene transfer of wild-type human apo A-I and human apo A-I(Milano) on endothelial progenitor cell (EPC) biology and on the progression of native atherosclerosis and allograft vasculopathy in C57BL/6 apo E(-/-) mice. Human apo A-I and apo A-I(Milano) transfer resulted in an equivalent increase of EPC number and function as well as EPC incorporation and endothelial regeneration in allografts and inhibited the progression of native atherosclerosis and allograft vasculopathy to a similar extent. In conclusion, the current head-to-head comparison indicates that human apo A-I(Milano) transfer is not superior compared to wild-type human apo A-I transfer.

Calcific aortic stenosis (AS) is a progressive disease that has, until recently, been considered to be a degenerative and unmodifiable process induced by long-lasting mechanical stress. However, histopathologic studies have now demonstrated that the development and progression of calcific AS is based on an active process, sharing a number of similarities with atherosclerosis. Inflammation, lipid infiltration, dystrophic calcification, ossification, platelet deposition and endothelial dysfunction have been observed in both diseases. In addition, several studies have suggested that AS and atherosclerosis share a number of risk factors, such as hypercholesterolemia, elevated lipoprotein (a), smoking, hypertension and diabetes. These findings suggest that statin therapy could be beneficial in AS by its lipid-lowering and/or anti-inflammatory effects, as is the case in atherosclerosis. Although this concept has been supported by experimental work and by four retrospective clinical studies observing significantly slower rates of hemodynamic progression in statin-treated patients, a prospective randomized trial (Scottish Aortic Stenosis and Lipid Lowering Trial, Impact on Regression [SALTIRE]; 80mg of atorvastatin vs placebo) yielded a negative result. In contrast to the retrospective analyses, according to the study protocol, patients with hyperlipidemia had to be excluded in this trial. A recent prospective study (Rosuvastatin Affecting Aortic Valve Endothelium [RAAVE]) treating hypercholesteremic patients with rosuvastatin, found a significantly slower rate of progression in these patients compared with patients with normal cholesterol levels who were left untreated, suggesting that statin therapy may only be beneficial in patients with hyperlipidemia. Lipid-lowering therapy with statins can, therefore, currently only be recommended in this subgroup of patients with AS.

Background: Cardiovascular disease (arteriosclerosis) is one of the most common causes of premature illness and death in industrialized countries. The established risk factors for its development are dyslipidemia, hypertension, diabetes mellitus, positive family history and smoking. The fetal programming hypothesis (i.e. that prenatal conditions are important for the development of cardiovascular diseases) has been used to explain causal mechanisms of arteriosclerosis, such as biological disturbances in the blood vessels of growth-retarded neonates. This hypothesis differs from the more traditional explanation that health in adulthood is more or less determined by accumulated incidents throughout life., Material and Methods: The article is based on a review of relevant literature retrieved from PubMed (from 1980-2007), including all references in the English articles, and own research., Results and Interpretations: Arteriosclerosis is a lifelong process, with a number of wellknown risk factors. The last 10-15 years have provided sound evidence for the connection between low birth weight and early morphological and physiological changes in vessels. This may explain why individuals with low birth weight have an increased risk of developing arteriosclerosis and provide a link between low birth weight and an increased mortality rate due to cardiovascular diseases in adult life.

Background: CD25+CD4+ regulatory T cells have been shown to suppress alloimmunity in various experimental settings. Here, we hypothesized that alloantigen-reactive regulatory T cells would reduce the severity of transplant arteriosclerosis., Methods: CD25+CD4+ T cells from CBA mice that were pretreated with C57BL/6 (B.6) blood (donor-specific transfusion, DST) and nondepleting anti-CD4 Ab (YTS 177) were cotransferred with naïve CBA CD25-CD4+"effector" T cells into CBA-rag-/- mice. These animals received aorta transplants from B.6 CD31-/- donors. CBA wild-type recipients of B.6 aorta grafts were pretreated with 177/DST directly. Some animals received 6x10(5) CD25+CD4+ T cells from pretreated mice to augment regulation on day -1. Grafts were harvested on day 30., Results: Luminal occlusion of the graft caused by neointima formation was 29.3+/-19.4% (n=5) after transfer of effector T cells only. Co-transfer of CD25+CD4+ regulators reduced occlusion significantly (2.4+/-3.3%, n=3; P=0.009). This effect was partially abrogated in the presence of a CTLA4 blocking Ab (11.1+/-4.7%, n=4; P=0.008). Pretreating immunocompetent CBA recipients of B.6 aortic allografts with 177/DST did not reduce transplant arteriosclerosis significantly (43.0+/-15.7%, n=5 vs. 56.6+/-16.8%, n=5; 177/DST vs. controls; P=0.22). However, when pretreated primary CBA recipients received an additional transfer of 6 x 10(5) CD25+CD4+ T cells procured from other mice pretreated with 177/DST before transplantation, luminal occlusion of the graft was markedly reduced (33.0+/-7.6%, n=5; P=0.002)., Conclusion: Regulatory T cells generated in vivo to alloantigen can prevent CD25-CD4+ T-cell-mediated transplant arteriosclerosis. In immunocompetent recipients, these cells have potential to be used as cellular immunotherapy to control transplant arteriosclerosis.

In order to investigate the origin of neointimal smooth muscle cells in transplant arteriosclerosis in rat aortic allograft, sex-mismatched bone marrow transplantation was performed from male Wistar rats to female Wistar rats. Four weeks after transplantation, the aortic transplant model was established by means of micro-surgery in rats. The recipients were divided into 4 groups: female Wistar-female Wistar aortic isografts, female SD female Wistar aortic allografts, male SD-male Wistar aortic allografts, female SD-chimera Wistar aortic allografts. Eight weeks after transplantation, aortic grafts were removed at autopsy and processed for histological evaluation and immunohistochemistry. The results indicated that excessive accumulation of alpha-SMA-positive smooth muscle cells resulted in significant neointima formation and vascular lumen stricture in rat aortic allografts. Neointima assay revealed that the neointimal area and NIA/MA ratio of transplanted artery were significantly increased in all of aortic allograft groups as compared with those in aortic isograft group (P<0.01). Neointimal smooth muscle cells were harvested from cryostat sections of aortic allograft by microdissection method. The Sry gene-specific PCR was performed, and the result showed that a distinct DNA band of 225 bp emerged in the male-male aortic allograft group and chimera aortic allograft group respectively, but not in the female-female aortic allograft group. It was suggested that recipient bone-marrow cells, as the origin of neointimal smooth muscle cells, contributed to the pathological neointimal hyperplasia of aortic allograft and transplant arteriosclerosis.

Recent studies suggest that reductions in circulating endothelial progenitor cells (EPCs) may contribute to the development of atherosclerosis. However, whether reduced circulating EPCs contribute to cerebrovascular disease remains undefined. We tested the hypothesis that reduced circulating EPCs was associated with an increased burden of carotid atherosclerosis. The level of circulating CD34+/KDR+ EPCs and the extent of carotid atherosclerosis were determined in 30 patients with a history of atherothrombotic ischaemic stroke and 30 age- and sex-matched controls (mean age: 63+/-2 years; 63% men). Stroke patients, compared with controls, had significantly higher carotid mean maximum intima-media thickness (mmIMT) (1.08+/-0.05 versus 0.90+/-0.02 mm, P=0.002), prevalence of carotid plaque (60.0 versus 23.3%, P=0.004) and a lower number of circulating CD34+/KDR+ EPCs (235.7+/-45.5 versus 400.4+/-56.8 cells/mul, P=0.027). The circulating CD34+/KDR+ EPC count correlated negatively with carotid mmIMT (r=-0.50, P<0.001), and was an independent risk factor for increased carotid mmIMT>1 mm (odds ratio (OR): 7.71; 95% confidence interval (CI): 1.62-36.74, P=0.010) and the presence of carotid plaque (OR: 7.04; 95% CI: 1.95-25.43, P=0.003). Furthermore, stroke patients with low (<25th percentile of controls) as compared to those with normal CD34+/KDR+ EPC count had a significantly greater carotid mmIMT (1.21+/-0.07 versus 0.93+/-0.05 mm, P=0.005) and a significantly higher prevalence of carotid plaque (87.5% versus 28.6%; P=0.001). Our observations suggested that reduced circulating EPC may contribute to the progression of carotid atherosclerosis. Circulating EPC count may provide a novel marker for the burden of carotid atherosclerosis.

Objective: Interplay between inflammation and angiogenesis is important in pathological reparative processes such as arteriosclerosis. We investigated how the two vascular endothelial growth factor receptors VEGFR-1 and -2 regulate these events in chronically rejecting cardiac allografts., Methods and Results: Chronic rejection in mouse cardiac allografts induced primitive myocardial, adventitial, and intimal angiogenesis with endothelial expression of CD31, stem cell marker c-kit, and VEGFR-2. Experiments using marker gene mice or rats as cardiac allograft recipients revealed that replacement of cardiac allograft endothelial cells with recipient bone marrow- or non-bone marrow-derived cells was rare and restricted only to sites with severe injury. Targeting VEGFR-1 with neutralizing antibodies in mice reduced allograft CD11b+ myelomonocyte infiltration and allograft arteriosclerosis. VEGFR-2 inhibition prevented myocardial c-kit+ and CD31+ angiogenesis in the allograft, and decreased allograft inflammation and arteriosclerosis., Conclusions: These results suggest interplay of inflammation, primitive donor-derived myocardial angiogenesis, and arteriosclerosis in transplanted hearts, and that targeting VEGFR-1 and -2 differentially regulate these pathological reparative processes.

Objectives: There are some lines of evidence about the role of telomeres in atherosclerotic plaque formation and development. Despite the role of telomerase in telomere elongation and protection, its role in atherosclerosis is not fully understood. The present study was designed to evaluate the importance of alternative splicing variants ofTERT (telomerase reverse transcriptase) in the atherosclerosis process., Methods and Results: Six Dutch-Polish rabbits were fed a high-cholesterol diet, and six control animals a normal diet. Alternative splicing was assessed by RT-PCR in aortic endothelial cells of these rabbits. Fatty streaks formation was assessed by H & E staining of aortic tissues. There were no significant differences in variants of TERT in control and test animals; neither in endothelial cells nor in aortic vessel wall., Conclusion: Our results demonstrated that a decrease in telomerase activity in atherosclerosis formation is not due to TERT gene alternative splicing.

Diabetes mellitus, the major cardiovascular risk factor, accentuates the inflammation and neovascularization processes leading to enhanced progression of atherosclerotic complications. Inflammation in diabetes mellitus is the key initiator of atherosclerotic process, which results in acute coronary events. Atherosclerosis evolves from the endothelial cell dysfunction and succeeding entry of hemodynamically derived leukocytes by migration, activation and production of lipid gruel leading to atheromatous plaque progression and subsequent regression. Diabetic plaque progression is associated with increased neovascularization, which is a nature's compliment in the sustenance of plaque growth by its nutrient supply. Neovessels may act as conduit for lipid debridment and alternative channel for inflammatory process. In addition, neovascularization induces intra-plaque hemorrhage due to the fragility of the neovessels and associated inflammation, resulting in plaque instability. The intra-plaque hemorrhage is a detrimental base, which begets the progress of atheroma by inducing oxidative stress and endothelial dysfunction. Intra-plaque hemorrhage is increased in diabetes with an associated increase in hemoglobin-haptoglobin complex (Hb-Hp2-2), which further induces oxidative stress and endothelial cell dysfunction. We conclude that inflammation and neovascularization of the plaque may act as major mechanism augmenting plaque instability in diabetes mellitus.

Protecting a vascularized graft from transplant arteriosclerosis requires inhibition of host immune effectors, but protective responses emanating from the graft aimed at maintaining/restoring "homeostasis" might be equally important. Expression of the "protective" genes A20, heme-oxygenase-1 (HO-1), Bcl-xL, inducible nitric oxide synthase (iNOS), and others in the vessel wall of rodent allografts and xenografts correlates with absence of transplant arteriosclerosis. Given the antiapoptotic and anti-inflammatory functions of these genes in endothelial cells and their anti-inflammatory/antiproliferative and sometimes proapoptotic function in neointimal smooth muscle cells, we hypothesize that their expression survives to limit graft injury by maintaining vascular integrity, controlling inflammation and promoting healing. Beyond this beneficial effect, their expression in the vessel wall may also positively impact the alloimmune response.

Inducible NO synthase (iNOS) is expressed by macrophages and smooth muscle cells in atherosclerotic lesions. Previously, we have established a mouse model for vein graft arteriosclerosis by grafting autologous jugular veins or vena cava to carotid arteries. Using this model, we studied the role of iNOS in the development of vein graft arteriosclerosis in iNOS(-/-) mice. Four weeks after grafting, neointimal hyperplasia of vein grafts in iNOS(-/-) mice was increased 2-fold compared with that of wild-type controls. Neointimal lesions contained mainly MAC-1+ macrophages and alpha-actin+ smooth muscle cells (SMCs) in both vein grafts of iNOS(-/-) and iNOS(+/+) mice. Immunofluorescence analysis revealed that increased iNOS expression in neointimal macrophages and SMCs of wild-type, but not iNOS(-/-), mice coincided with increased vascular endothelial growth factor (VEGF) expression in vein grafts. When vein grafts were performed in iNOS(-/-)/TIE2-LacZ transgenic mice expressing LacZ gene only in endothelial cells, the number of beta-galactosidase+ cells in iNOS(-/-) vein grafts were significantly decreased. Furthermore, treatment with the NOS inhibitor NG-nitro-L-arginine methyl ester resulted in delayed endothelial progenitor cell attachment, whereas L-arginine intake through drinking water enhanced endothelial repair. Interestingly, local application of VEGF to iNOS(-/-) vein grafts restored endothelial progenitor homing and reduced neointimal lesions, whereas the VEGF receptor inhibitor SU1498 increased the lesion formation. Additionally, iNOS-deficient SMCs showed a low level of VEGF production in response to interleukin 1beta stimulation. Thus, iNOS deficiency accelerates neointima formation by abrogating VEGF production and endothelial progenitor cell attachment and differentiation.

Background: Rheumatoid arthritis (RA) is associated with increased morbidity and mortality attributable to accelerated atherosclerosis and cardiovascular events., Objective: To determine the role played by endothelial progenitor cells (EPC) in the defence system against arteriosclerosis., Methods: The number and function of EPC in 13 young patients with RA with low disease activity (DAS28 3.5 (0.3)) and 13 healthy control subjects was studied. Endothelial function was investigated by agonist-induced, endothelium dependent vasodilatation measured by the forearm blood flow technique. Migratory activity and adhesion of EPC to tumour necrosis factor alpha (TNFalpha) activated mature endothelial cells and components of the extracellular matrix were tested in vitro. Putative precursor populations (CD34(+), CD34(+)/CD133(+), and CD34(+)/KDR(+) haematopoietic stem cells) were measured by flow cytometric analysis., Results: Acetylcholine-induced, endothelium dependent vasodilatation was reduced by about 50% in patients with RA, indicating endothelial dysfunction, whereas endothelium-independent vasodilatation in response to glyceryl trinitrate was at control level. Significantly reduced numbers of EPC were found in the patients compared with controls. Migratory activity of EPC was decreased in patients with RA. Adhesion to mature endothelial cells after activation with TNFalpha was enhanced only in controls. The adhesion to matrix proteins and the number of putative precursor cell lineages was comparable in both groups., Conclusion: Endothelial dysfunction in patients with RA with low grade inflammation is associated with a reduced number and partial dysfunction of EPC. Further studies are needed to explore whether interventions that potentially ameliorate the number and function of EPC also improve endothelial function in these patients.

Introduction: Earlier we have demonstrated a prothrombotic state in spontaneously atherogenic rodents kept on Western-style high fat diet. The aim of the present study was to investigate the cellular mechanism of such prothrombotic state., Materials and Methods: Two kinds of diets, Western-style high fat diet containing 20% fat (w/w) and 0.05% cholesterol (w/w) and low fat diet containing 7% fat without cholesterol based on AIN93G, were added to diet-sensitive apolipoprotein E and low-density lipoprotein receptor double deficient male mice for 12 or 18 weeks from 6 weeks of age. Atherosclerosis was assessed by morphometry of the aortic wall or lipid-stained lesions. Endothelial function was measured by flow-mediated vasodilation (FMV) of the femoral artery. Platelet reactivity was measured ex vivo by a shear-induced platelet aggregation test., Results and Conclusions: 12 weeks feeding of mice with high fat diet significantly impaired FMV, as compared with mice fed with low fat diet (P<0.05). In contrast, there was no significant difference in the lipid-stained areas and in the reactivity of platelets between the two groups. 18 weeks feeding with high fat diet significantly impaired FMV (P<0.05) and enhanced both lipid-stained areas (P<0.05) and platelet reactivity (P<0.01). These findings show that in high fat diet-induced prothrombotic state, endothelial dysfunction precedes both the morphologically detectable lesions and the enhancement of platelet reactivity.

The objective of this study was to evaluate the influence of ingested l-arginine, l-citrulline, and antioxidants (vitamins C and E) on the progression of atherosclerosis in rabbits fed a high-cholesterol diet. The fatty diet caused a marked impairment of endothelium-dependent vasorelaxation in isolated thoracic aorta and blood flow in rabbit ear artery in vivo, the development of atheromatous lesions and increased superoxide anion production in thoracic aorta, and increased oxidation-sensitive gene expression [Elk-1 and phosphorylated cAMP response element-binding protein]. Rabbits were treated orally for 12 weeks with l-arginine, l-citrulline, and/or antioxidants. l-arginine plus l-citrulline, either alone or in combination with antioxidants, caused a marked improvement in endothelium-dependent vasorelaxation and blood flow, dramatic regression in atheromatous lesions, and decrease in superoxide production and oxidation-sensitive gene expression. These therapeutic effects were associated with concomitant increases in aortic endothelial NO synthase expression and plasma NO(2)(-)+NO(3)(-) and cGMP levels. These observations indicate that ingestion of certain NO-boosting substances, including l-arginine, l-citrulline, and antioxidants, can abrogate the state of oxidative stress and reverse the progression of atherosclerosis. This approach may have clinical utility in the treatment of atherosclerosis in humans.

The release of microvesicles ('platelet microparticles', PMPs) by activated platelets has been shown to be an integral part of the thrombotic process. PMPs are believed to mediate many biological processes as they possess various platelet membrane proteins and bioactive lipids. Of note, there is a growing body of evidence that PMPs are involved in all stages in the pathobiology of atherosclerosis. In addition to their role in thrombosis, PMPs may also have a pro-inflammatory effect, which promotes the development of atherosclerosis. Also, bioactive lipids in PMPs have been shown to have important effects on angiogenesis. This review summarises the various studies on the possible role of PMPs in the progression of atherosclerosis.

Noninvasive assessment of vascular dysfunction in the pediatric population has taken advantage of the development of high-resolution ultrasound techniques. The most frequently used methods are the quantification of flow-mediated endothelium-dependent dilation of the brachial artery and measurement of the intima-media thickening of the carotid artery. Both reduced flow-mediated dilation and increased intima-media thickness have been proven to correlate with late cardiovascular events and/or mortality in adults. As these noninvasive methods can easily be applied in children, there have been recent investigations in high-risk pediatric patients harboring classical cardiovascular risk factors. Endothelial dysfunction and increased thickness of the intima media are currently observed in children with familial hypercholesterolemia, obesity, and type 1 diabetes mellitus. The association of early vascular dysfunction with a known risk factor is an important issue as these anomalies precede the formation of atherosclerotic plaques. Therefore, they may help in stratification of the risk for cardiovascular event and to better tailor therapeutic interventions in at risk children. Finally, these methods have been applied in specific pediatric populations, such as children with end-stage renal disease, chronic parenteral nutrition, HIV infection, and coarctation of the aorta. In these conditions, endothelial dysfunction and vascular remodeling are also present early in life and these data raise new possibilities in the understanding of the pathogenesis of atherosclerosis in these populations.

Blood-flow-induced shear stress acting on the arterial wall is of paramount importance in vascular biology. Endothelial cells sense shear stress and largely control its value in a feedback-control loop by adapting the arterial dimensions to blood flow. Nevertheless, to allow for variations in arterial geometry, such as bifurcations, shear stress control is modified at certain eccentrically located sites to let it remain at near-zero levels. In the presence of risk factors for atherosclerosis, low shear stress contributes to local endothelial dysfunction and eccentric plaque build up, but normal-to-high shear stress is atheroprotective. Initially, lumen narrowing is prevented by outward vessel remodeling. Maintenance of a normal lumen and, by consequence, a normal shear stress distribution, however, prolongs local unfavorable low shear stress conditions and aggravates eccentric plaque growth. While undergoing such growth, eccentric plaques at preserved lumen locations experience increased tensile stress at their shoulders making them prone to fissuring and thrombosis. Consequent loss of the plaque-free wall by coverage with thrombus and new tissue may bring shear-stress-controlled lumen preservation to an end. This change causes shear stress to increase, which as a new condition may transform the lesion into a rupture-prone vulnerable plaque. We present a discussion of the role of shear stress, in setting the stage for the generation of rupture-prone, vulnerable plaques, and how this may be prevented.

The cellular and extracellular matrix accumulations that comprise the lesions of atherosclerosis are driven by local release of cytokines at sites of predilection for lesion formation, and by the specific attraction and activation of cells expressing receptors for these cytokines. Although cytokines were originally characterized for their potent effects on immune and inflammatory cells, they also promote endothelial cell dysfunction and alter smooth muscle cell (SMC) phenotype and function, which can contribute to or retard vascular pathologies. This review summarizes in vivo studies that have characterized endothelial- and smooth muscle-specific effects of altering cytokine signaling in vascular disease. Although multiple reports have identified cytokines as pivotal players in endothelial and SMC responses in vascular disease, they also have highlighted the need to delineate the critical genes and specific cellular functions regulated by individual cytokine signaling pathways.

Objective: To observe the effect of captopril and valsartan on preventing the formation of atherosclerosis plaque in rabbit atherosclerotic models., Methods: The atherosclerotic models of rabbits fed with high-cholesterol diet were used. There were four groups: high cholesterol group, high cholesterol + captopril group, high cholesterol + valsartan group, normal food group. The intima-media thickness in abdominal aortic were measured by ultrasound. The pathogenic features of the arterial walls were showed by HE stain and observed by light microscope., Results: There were less atherosclerotic plaque in high cholesterol + captopril group and high cholesterol + valsartan group than in cholesterol group. The intima-media thickness in high cholesterol + captopril group and in high cholesterol + valsartan group were much more decreased than in high cholesterol group (0.05 +/- 0.005, 0.05 +/- 0.007 vs 0.07 +/- 0.100, P < 0.01). The connection of the endothelial cells were less damaged in high cholesterol + captopril group and high cholesterol + valsartan group than in high cholesterol group., Conclusions: Ti is true that angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB) have the effect of preventing or decreasing the formation of atherosclerotic plaque in arterial wall. The findings suggest that ACEI and/or ARB should be first chosen for those with hypertension and with atherosclerotic risk factors or atherosclerotic diseases.

Understanding of the pathophysiology of atherosclerosis can provide new strategies for the prevention and treatment of patients with this common disease. Clinical, epidemiologic, and basic molecular science studies have identified oxidative stress as a factor contributing to the development and progression of atherosclerosis. Oxidative stress also participates in the pathogenesis of endothelial dysfunction and hypertension, two important factors in many patients with atherosclerosis. Further, it contributes to mechanisms of disease progression such as lipid oxidation and vascular remodeling. This article reviews the role of reactive oxygen species and oxidative stress in atherosclerosis.

Objective: Sedentary lifestyle is associated with increased cardiovascular events. The underlying molecular mechanisms are incompletely understood. Reactive oxygen species (ROS) contribute to endothelial dysfunction and atherosclerosis. An important source of vascular ROS is the NADPH oxidase., Methods and Results: C57BL6 mice were subjected to regular housing (physical inactivity) or voluntary training on running wheels (6 weeks). Inactivity increased vascular lipid peroxidation to 148+/-9% and upregulated superoxide release to 176+/-17% (L-012 chemiluminescence) and 188+/-29% (cytochrome C reduction assay), respectively. ROS production was predominantly increased in the endothelium and the media (dihydroethidium fluorescence). Activity of the NADPH oxidase was increased to 154+/-22% in the sedentary group. Rac1 GST-PAK pull-down assays showed an upregulation of rac1 activity to 161+/-14%. Expression levels of the subunits nox1, p47phox, and p67phox were increased. To address the significance of the antioxidative effects of running, experiments were repeated in apolipoprotein E-deficient mice treated with a high-cholesterol diet. Inactivity increased vascular superoxide production and impaired endothelium-dependent vasorelaxation. Atherosclerotic lesion formation was significantly accelerated in sedentary mice., Conclusions: Inactivity increases vascular NADPH oxidase expression and activity and enhances vascular ROS production, which contributes to endothelial dysfunction and atherosclerosis during sedentary as opposed to physically active lifestyle.

Integrins are heterodimeric alpha/beta receptors that link the cytoskeleton with the extracellular matrix, thereby regulating several cell functions important in atherosclerosis. In vitro, the subtilisin/kexin-like proprotein convertases (PCs), namely PC5 and furin, have been shown to be responsible for the endoproteolytic activation of the alpha(v) integrin subunit. Based on their cleavage activity, these PCs are potential targets in atherosclerosis. In the present study, we investigated the localization of furin and PC5 in different stages of human atherosclerosis. Immunohistochemical analysis of furin and PC5 revealed their presence in vascular smooth-muscle cells and endothelial cells in atherosclerotic and non-atherosclerotic lesions. However, in the more advanced lesions, furin and PC5 staining was significantly expressed in macrophages/foam cells. In vitro, THP-1 derived macrophages contained furin and PC5, and maturation of monocytes to macrophages was accompanied by enhanced alpha(v)beta3 cell-surface expression. Inhibition of furin/PC5 with the specific pharmacological furin-like PC-inhibitor dec-CMK inhibited alpha(v) endoproteolytic activation but did not abolish alpha(v)beta3 cell-surface expression. This indicates that furin/PC5 is required for alpha(v) endoproteolytic activation but not for alpha(v) routing and sorting to the cell surface. In conclusion, our study demonstrates that furin and PC5 are significantly expressed in mononuclear cells in advanced human atherosclerotic lesions, where they regulate alpha(v) endoproteolytic activation.

L-arginine is the substrate for the enzyme nitric oxide synthase (NOS), which is responsible for the production of nitric oxide (NO), an endogenous messenger molecule involved in many of the processes associated with the development of atherosclerosis. Acute and chronic administration of L-arginine has been shown to improve endothelial function in animal models of hypercholesterolemia and atherosclerosis. Therefore, a lot of studies were conducted to elucidate whether dietary L-arginine supplementation can augment NO production in man and thereby improve vascular health. In this review the results of studies of intravenous and oral L-arginine supplementation with a colorful spectrum of doses, study duration and surrogate parameters of endothelial function are summarized. The pharmacokinetics of L-arginine have been investigated, side effects are rare and mostly mild and dose-dependent. Several possible mechanisms of action of L-arginine are discussed. An assessment of L-arginine as a therapeutic agent from the point of view of a clinical pharmacologist is given.

The pathogenesis, which is primarily responsible for Alzheimer's disease (AD) and cerebrovascular accidents (CVA), seems to involve chronic hypoperfusion. The role of hypoperfusion, as a key factor for vascular lesions that causes oxidative stress, appears to be widely accepted as an initiator of AD. Specifically, accumulated oxidative stress increases vascular endothelial permeability and promotes leukocyte adhesions, which is coupled with alterations in endothelial signal transduction and redox-regulated transcription factors. Based on these recent findings, we hypothesize that the cellular and molecular mechanisms by which hypoperfusion-induced reactive oxygen species (ROS) accumulation impairs endothelial barrier function and promotes leukocyte adhesion induces alterations in normal vascular function and results in the development of AD. We are theorizing that mitochondria play a key role in the generation of ROS, resulting in oxidative damage to neuronal cell bodies, as well as other cellular compartment in the AD brain. All of these changes have been found to accompany AD pathology. We have studied the ultrastructural features of vascular lesions and mitochondria in brain vascular wall cells from human AD, yeast artificial chromosome (YAC) and C57B6/SJL transgenic positive (Tg+) mice overexpressing amyloid beta precursor protein (AbetaPP). In situ hybridization using mitochondrial DNA (mtDNA) probes for human wild and 5 kb deleted types and mouse types was performed along with immunocytochemistry using antibodies against amyloid precursor protein (APP), 8-hydroxy-2'-guanosine (8-OHG) and cytochrome c oxidase (COX). There was a higher degree of amyloid deposition, overexpression of oxidative stress markers, mitochondria DNA deletion and mitochondrial structural abnormality in the vascular walls of the human AD, YAC and C57B6/SJL Tg (+) mice compared to age-matched controls. Therefore, selective pharmacological intervention, directed for abolishing the chronic hypoperfusion state, would possibly change the natural course of development of dementing neurodegeneration.

Viral and bacterial pathogens have long been suspected to affect atherogenesis directly. However, mechanisms linking innate immunity to chronic inflammatory diseases such as atherosclerosis are still poorly defined. Here we show that infection of primary human aortic smooth muscle cells (HAOSMC) with human cytomegalovirus (HCMV) leads to activation of the novel IkappaB kinase (IKK)-related kinase, Tank-binding kinase-1 (TBK1), a major effector of the cellular innate immune response. We demonstrate that part of the HCMV inflammatory response is most likely mediated via this novel kinase because the canonical IKK complex was only poorly activated upon infection of HAOSMC. An increase in TBK1 phosphotransferase activity led to a strong activation of the interferon regulatory factor (IRF)-3 transcription factor as measured by its C-terminal phosphorylation, dimerization, and DNA binding activity. In addition to TBK1, HAOSMC also express another IKK-related kinase isoform, IKKepsilon, albeit at a lower level. Nevertheless, both isoforms were required for full activation of IRF-3 by HCMV. The transcripts of proatherosclerotic genes Ccl5 (encoding for the chemokine RANTES (regulated upon activation, normal T cell expressed and secreted)) and Cxcl10 (encoding for the chemokine IP-10 (interferon-gamma-inducible protein 10)) were induced in an IRF-3-dependent manner after HCMV infection of smooth muscle cells. In addition, cytokine arrays analysis showed that RANTES and IP-10 were the predominant chemokines present in the supernatant of HCMV-infected HAOSMC. Activation of the TBK1/IRF-3 pathway was independent of epidermal growth factor receptor and pertussis toxin-sensitive G protein-coupled receptor activation. Our results thus add additional molecular clues to a possible role of HCMV as a modulator of atherogenesis through the induction of a proinflammatory response that is, in part, dependent of an IKK-related kinase pathway.

Atherosclerotic cardiovascular disease remains the leading cause of death in the industrialized world. Most cardiovascular deaths result from acute coronary syndromes, including unstable angina pectoris and acute myocardial infarction. Coronary syndromes often arise from acute coronary thrombosis, itself commonly a result of disruption or rupture of the fibrous cap of a lipid-laden atherosclerotic plaque. Despite this huge clinical burden of atherosclerotic plaque instability, our understanding of the molecular mechanisms mediating atherosclerotic plaque disruption and rupture, at a cellular level, remains limited. Placed in a clinical context, this review discusses our current understanding of the molecular basis for atherosclerotic plaque instability, with particular emphasis on the process of apoptosis-or programmed cell death-seen increasingly as playing a key role in a number of cell types within the vessel wall.