Distinct patterns of expression of fibroblast growth factors and their receptors in human atheroma and nonatherosclerotic arteries. Association of acidic FGF with plaque microvessels and macrophages

NF-κB and its crosstalk with endoplasmic reticulum stress in atherosclerosis

Atherosclerosis (AS) is a common cardiovascular disease with complex pathogenesis, in which multiple pathways and their interweaving regulatory mechanism remain unclear. The primary transcription factor NF-κB plays a critical role in AS via modulating the expression of a series of inflammatory mediators under various stimuli such as cytokines, microbial antigens, and intracellular stresses. Endoplasmic reticulum (ER) stress, caused by the disrupted synthesis and secretion of protein, links inflammation, metabolic signals, and other cellular processes via the unfolded protein response (UPR). Both NF-κB and ER stress share the intersection regarding their molecular regulation and function and are regarded as critical individual contributors to AS. In this review, we summarize the multiple interactions between NF-κB and ER stress activation, including the UPR, NLRP3 inflammasome, and reactive oxygen species (ROS) generation, which have been ignored in the pathogenesis of AS. Given the multiple links between NF-κB and ER stress, we speculate that the integrated network contributes to the understanding of molecular mechanisms of AS. This review aims to provide an insight into these interactions and their underlying roles in the progression of AS, highlighting potential pharmacological targets against the atherosclerotic inflammatory process.

miR-188-3p Inhibits Vascular Smooth Muscle Cell Proliferation and Migration by Targeting Fibroblast Growth Factor 1 (FGF1)

Background

As one of the crucial causes leading to cardiovascular disease, atherosclerosis (AS) develops in association with the dysfunction of vascular smooth muscle cells (VSMCs). However, the associated mechanism of the proliferation and migration in VSMCs requires further elucidation.

Material/Methods

Human VSMCs and ApoE-knockout (ApoE^−/−) mice were used to establish AS cell and animal models, respectively. Expression levels of miR-188-3p and fibroblast growth factor 1 (FGF1) mRNA were detected using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Western blot was used to assess FGF1 protein expression. The proliferation, migration, and apoptosis of the cells were determined using MTT, BrdU, and Transwell assays, as well as flow cytometry analysis. The interaction between miR-188-3p and FGF1 was validated using dual-luciferase reporter gene assay, qRT-PCR, and Western blot analysis.

Results

MiR-188-3p was found to be significantly decreased in the serum of AS patients and ApoE^−/− mice as well as VSMCs of ApoE^−/− mice and human VSMCs treated with oxidized low-density lipoprotein. MiR-188-3p repressed the proliferation and migration of VSMCs but promoted apoptosis of VSMCs. The binding site between miR-188-3p and 3′ untranslated region (3′-UTR) of FGF1 was identified, and FGF1 was verified as a target gene of miR-188-3p. Restoration of FGF1 reversed the effects of miR-188-3p on VSMCs.

Conclusions

MiR-188-3p suppresses the proliferation and migration of VSMCs and induces their apoptosis through targeting FGF1.

Vulnerable Plaque: A Review of Current Concepts in Pathophysiology and Imaging

Advances in our understanding of the natural history and biology of atherosclerotic vascular disease led to the concept of a vulnerable plaque (VP), which is predisposed toward more rapid progression and acute coronary events. With newer technologies, we now have at our disposal high-quality imaging studies, both invasive and noninvasive, which promise in identifying plaque characteristics that make it more vulnerable. Upcoming trials aim to evaluate the utility of imaging VP in predicting clinical events. We discuss the role of VP imaging in managing atherosclerotic vascular disease.

Selected Growth Factors in Peritoneal Dialysis: Their Relationship to Markers of Inflammation, Dialysis Adequacy, Residual Renal Function, and Peritoneal Membrane Transport

Objectives

Markers of chronic inflammation, acute-phase reactants, and growth factors may be concomitantly involved in a number of pathologic processes in the general population and uremic patients. In addition, growth factors may influence peritoneal membrane transport characteristics. However, the association between plasma growth factors, markers of chronic inflammation, and peritoneal membrane transport remains largely unknown. The aim of this study was to evaluate the relationship between plasma levels of selected growth factors [basic fibroblast growth factor (bFGF), transforming growth factor β1 (TGFβ1), vascular endothelial growth factor (VEGF)] and markers of chronic inflammation [interleukin (IL)-6, C-reactive protein (CRP), and fibrinogen] in continuous ambulatory peritoneal dialysis (CAPD) patients. The potential link between the above substances and dialysis adequacy was also explored.

Design

Single-center, cross-sectional study.

Setting

Peritoneal Dialysis Unit, Medical Faculty, Jagiellonian University Hospital, Kraków, Poland.

Patients

32 stable end-stage renal disease patients (13 M, 19 F; mean age 53.6 ± 13.7 years) on CAPD for a median period of 19.5 months. Patients free from signs and symptoms of any inflammatory disease (including peritonitis) for at least 3 months were included into the study. All patients underwent measurements of dialysis dose [Kt/V, weekly creatinine clearance (wCCr)] and peritoneal solute transport using a standard peritoneal equilibration test (PET).

Methods

TGFβ1, bFGF, VEGF, and IL-6 were measured with ELISA, CRP was assayed with immunonephelometry, and fibrinogen with Multifibren U reagent (Dade Behring Marburg GmbH, Marburg, Germany). Nephron 97 for Windows software was used to assess dialysis adequacy.

Results

Significant positive correlations between plasma bFGF and IL-6, as well as fibrinogen concentrations ( R = 0.36, p < 0.05 and R = 0.39, p < 0.05, respectively), were found. VEGF correlated significantly with IL-6 and CRP ( R = 0.65, p < 0.0001 and R = 0.51, p < 0.005, respectively). An association between VEGF and bFGF was also found ( R = 0.59, p < 0.0005). Serum level of TGFβ1 revealed no relationship with any marker of acute-phase activation, remaining growth factors, or dialysis adequacy. Positive correlation between TGFβ1 concentration and dialysate-to-plasma ratio for creatinine in PET ( R = 0.35, p < 0.05) was found. In addition, patients with lower solute transport (low/low-average transporters) had lower serum levels of both bFGF and TGFβ1 compared to patients with higher solute transport. Patients with total wCCr > 60 L/week/m2 were characterized by lower levels of bFGF and IL-6. Serum level of IL-6 and plasma levels of bFGF and VEGF were significantly lower among subjects with residual renal function (RRF) > 2.0 mL/minute.

Conclusions

Our results indicate that systemic inflammation in peritoneal dialysis patients is associated with increased plasma VEGF and bFGF but not TGFβ1. The negative correlation with RRF suggests that either the renal clearance of these cytokines and growth factors may contribute to their elimination, or cytokines and growth factors have a negative impact on RRF. We also suggest an association between serum levels of growth factors tested and peritoneal membrane function.

Both gut microbiota and cytokines act to atherosclerosis in ApoE-/- mice

BACKGROUND

Several studies have suggested a role for the gut microbiome and cytokines in atherosclerosis development, but combined analyses of the changes of the gut microbiota and cytokines have not been explored previously.

METHODS

We treated ApoE-/- and wild-type mice with a high-fat diet for 12 weeks. The gut microbiome and cytokine composition were analyzed using 16S ribosomal DNA sequencing and RayBio Quantibody Arrays, respectively. GO and KEGG analysis were performed to rationalize the potential mechanisms involved in the process of atherosclerosis.

RESULTS

Gut bacterial characteristics in ApoE-/- mice were clearly separated and 21 gut bacterial clades were detected by the LEfSe analysis showing significant differences during the development of atherosclerosis. The relative abundance of Verrucomicrobia, Bacteroidaceae, Bacteroides, and Akkermansia showed significant positive correlations with serum total cholesterol, triglyceride (TG), high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Additionally, the relative abundance of Ruminococcaceae was positive with the level of HDL and the abundance of Rikenellaceae showed a negative relationship with the level of TG and LDL. Thirteen differentially expressed proteins were identified with P-value < 0.05. CXCL5, FGF2, and E-Selectin were significantly negatively associated with Akkermansia and Verrucomicrobia. Additionally, CXCL5 was significantly negatively correlated with Bacteroides and Bacteroidaceae. Three "cellular component" subcategories, 24 ″molecular function" subcategories, 752 ″biological process" subcategories and 29 statistically remarkable KEGG pathway categories were identified.

CONCLUSIONS

Gut microbiota changes of the mice having atherosclerosis and their relationship with the inflammatory status could be one of the major etiological mechanisms underlying atherosclerosis.

MicroRNAs in endothelial cell homeostasis and vascular disease

PURPOSE OF REVIEW

Since the first discovery of microRNAs (miRNAs) in 1993, the involvement of miRNAs in different aspects of vascular disease has emerged as an important research field. In this review, we summarize the fundamental roles of miRNAs in controlling endothelial cell functions and their implication with several aspects of vascular dysfunction.

RECENT FINDINGS

MiRNAs have been found to be critical modulators of endothelial homeostasis. The dysregulation of miRNAs has been linked to endothelial dysfunction and the development and progression of vascular disease which and open new opportunities of using miRNAs as potential therapeutic targets for vascular disease.

SUMMARY

Further determination of miRNA regulatory circuits and defining miRNAs-specific target genes remains key to future miRNA-based therapeutic applications toward vascular disease prevention. Many new and unanticipated roles of miRNAs in the control of endothelial functions will assist clinicians and researchers in developing potential therapeutic applications.

Acid fibroblast growth factor facilitates the progression of atherosclerotic plaques regardless of alterations in serum lipid expression levels in HFD‑fed ApoE‑/‑ mice

Atherosclerosis is recognized at present as a chronic metabolic disease of the arteries that leads to multifocal plaque development. Previous studies have reported that acid fibroblast growth factor (aFGF) is a critical therapeutic regulator in numerous chronic metabolic disorders. However, there is currently no direct evidence indicating whether aFGF serves a therapeutic role in atherosclerosis. In the present study, the role of aFGF in atherosclerotic lesion development was investigated by examining high‑fat diet (HFD)‑fed apolipoprotein E (ApoE)‑/‑ mice and parenteral administration of aFGF. Increased expression of aFGF and peroxisome proliferator‑activated receptor α (PPARα) was observed during atherosclerotic lesion development. The parenteral delivery of aFGF facilitated the progression of atherosclerosis without altering serum lipid expression levels in HFD‑fed ApoE‑/‑ mice. Furthermore, it was demonstrated that aFGF increased the expression of PPARα and inflammatory cytokines. The present results provided evidence that aFGF accelerates the progression of atherosclerosis and suggested that aFGF may be a potential therapeutic target for the prevention of atherosclerosis development.

Association of FGF-2 Concentrations with Atheroma Progression in Chronic Kidney Disease Patients

BACKGROUND AND OBJECTIVES

Atherosclerosis is highly prevalent in CKD. The rate of progression of atherosclerosis is associated with cardiovascular events. Fibroblast growth factor 2 (FGF-2) is a member of the FGF family with potentially both protective and deleterious effects in the development of atherosclerosis. The role of circulating FGF-2 levels in the progression of atherosclerosis in CKD is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used a multicenter, prospective, observational cohorts study of 481 patients with CKD. We determined the presence of atheroma plaque in ten arterial territories by carotid and femoral ultrasounds. Progression of atheromatosis was defined as an increase in the number of territories with plaque after 24 months. Plasma levels of FGF-2 were measured by multiplex analysis. A multivariable logistic regression analysis was performed to determine whether plasma FGF-2 levels were associated with atheromatosis progression.

RESULTS

Average age of the population was 61 years. The percentage of patients in each CKD stage was 51% in stage 3, 41% in stages 4-5, and 8% in dialysis. A total of 335 patients (70%) showed plaque at baseline. Atheromatosis progressed in 289 patients (67%). FGF-2 levels were similar between patients with or without plaque at baseline (79 versus 88 pg/ml), but lower in patients with atheromatosis progression after 2 years (78 versus 98 pg/ml; P<0.01). In adjusted analyses, higher plasma FGF-2 was associated with lower risk of atheromatosis progression (odds ratio [OR], 0.86; 95% confidence interval [95% CI], 0.76 to 0.96; per 50 pg/ml increment). Analysis of FGF-2 in tertiles showed that atheroma progression was observed for 102 participants in the lowest tertile of FGF-2 (reference group), 86 participants in the middle tertile of FGF-2 (adjusted OR, 0.70; 95% CI, 0.40 to 1.20), and 74 participants in the lowest tertile of FGF-2 (adjusted OR, 0.48; 95% CI, 0.28 to 0.82).

CONCLUSIONS

Low FGF-2 levels are independently associated with atheromatosis progression in CKD.

FGF21 mimetic antibody stimulates UCP1-independent brown fat thermogenesis via FGFR1/βKlotho complex in non-adipocytes

Objective

Fibroblast Growth Factor 21 (FGF21) is a potent stimulator of brown fat thermogenesis that improves insulin sensitivity, ameliorates hepatosteatosis, and induces weight loss by engaging the receptor complex comprised of Fibroblast Growth Factor Receptor 1 (FGFR1) and the requisite coreceptor βKlotho. Previously, recombinant antibody proteins that activate the FGFR1/βKlotho complex were proposed to act as an FGF21-mimetic; however, in vivo action of these engineered proteins has not been well studied.

Methods

We investigated the mechanism by which anti-FGFR1/βKlotho bispecific antibody (bFKB1) stimulates thermogenesis in UCP1-expressing brown adipocytes using genetically engineered mice. Anti-FGFR1 agonist antibody was also used to achieve brown adipose tissue restricted activation in transgenic mice.

Results

Studies with global Ucp1-deficient mice and adipose-specific Fgfr1 deficient mice demonstrated that bFKB1 acts on targets distal to adipocytes and indirectly stimulates brown adipose thermogenesis in a UCP1-independent manner. Using a newly developed transgenic system, we also show that brown adipose tissue restricted activation of a transgenic FGFR1 expressed under the control of Ucp1 promoter does not stimulate energy expenditure. Finally, consistent with its action as a FGF21 mimetic, bFBK1 suppresses intake of saccharin-containing food and alcohol containing water in mice.

Conclusions

Collectively, we propose that FGFR1/βKlotho targeted therapy indeed mimics the action of FGF21 in vivo and stimulates UCP1-independent brown fat thermogenesis through receptors outside of adipocytes and likely in the nervous system.

•

Anti-FGFR1/βKlotho bispecific antibody stimulates energy expenditure in Ucp1-deficient mice.

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Anti-FGFR1/βKlotho bispecific antibody stimulates energy expenditure in adipocyte-selective Fgfr1-deficient mice.

•

Brown adipocyte restricted activation of transgenic FGFR1 does not stimulate energy expenditure.

•

Anti-FGFR1/βKlotho bispecific antibody mimics FGF21, inducing sweet and alcohol aversion.

Mechanisms of Myeloid Cell Modulation of Atherosclerosis

Inflammation furnishes a series of pathogenic pathways that couple the risk factors for atherosclerosis with altered behavior of the intrinsic cells of the arterial wall, endothelium, and smooth muscle and promote the disease and its complications. Myeloid cells participate critically in all phases of atherosclerosis from initiation through progression, and ultimately the thrombotic consequences of this disease. Foam cells, lipid-laden macrophages, constitute the hallmark of atheromata. Much of the recent expansion in knowledge of the roles of myeloid cells in atherosclerosis revolves around the functional contributions of subsets of monocytes, precursors of macrophages, the most abundant myeloid cells in the atheroma. Proinflammatory monocytes preferentially accumulate in nascent atherosclerotic plaques. The most dramatic manifestations of atherosclerosis result from blood clot formation. Myocardial infarction, ischemic stroke, and abrupt limb ischemia all arise primarily from thrombi that complicate atherosclerotic plaques. Myeloid cells contribute pivotally to triggering thrombosis, for example, by elaborating enzymes that degrade the plaque's protective extracellular matrix, rendering it fragile, and by producing the potent procoagulant tissue factor. While most attention has focused on mononuclear phagocytes, the participation of polymorphonuclear leukocytes may aggravate local thrombus formation. Existing therapies such as statins may exert some of their protective effects by altering the functions of myeloid cells. The pathways of innate immunity that involve myeloid cells provide a myriad of potential targets for modifying atherosclerosis and its complications, and provide a fertile field for future attempts to address the residual burden of this disease, whose global prevalence is on the rise.

Smooth muscle FGF/TGFβ cross talk regulates atherosclerosis progression

The conversion of vascular smooth muscle cells (SMCs) from contractile to proliferative phenotype is thought to play an important role in atherosclerosis. However, the contribution of this process to plaque growth has never been fully defined. In this study, we show that activation of SMC TGFβ signaling, achieved by suppression of SMC fibroblast growth factor (FGF) signaling input, induces their conversion to a contractile phenotype and dramatically reduces atherosclerotic plaque size. The FGF/TGFβ signaling cross talk was observed in vitro and in vivo In vitro, inhibition of FGF signaling increased TGFβ activity, thereby promoting smooth muscle differentiation and decreasing proliferation. In vivo, smooth muscle-specific knockout of an FGF receptor adaptor Frs2α led to a profound inhibition of atherosclerotic plaque growth when these animals were crossed on Apoe(-/-) background and subjected to a high-fat diet. In particular, there was a significant reduction in plaque cellularity, increase in fibrous cap area, and decrease in necrotic core size. In agreement with these findings, examination of human coronary arteries with various degrees of atherosclerosis revealed a strong correlation between the activation of FGF signaling, loss of TGFβ activity, and increased disease severity. These results identify SMC FGF/TGFβ signaling cross talk as an important regulator of SMC phenotype switch and document a major contribution of medial SMC proliferation to atherosclerotic plaque growth.

Intraplaque neovascularization as a novel therapeutic target in advanced atherosclerosis

INTRODUCTION

Atherosclerosis is a lipid-driven inflammatory process with a tremendously high mortality due to acute cardiac events. There is an emerging need for new therapies to stabilize atherosclerotic lesions. Growing evidence suggests that intraplaque (IP) neovascularisation and IP hemorrhages are important contributors to plaque instability.

AREAS COVERED

Neovascularization is a complex process that involves different growth factors and inflammatory mediators of which their individual significance in atherosclerosis remains poorly understood. This review discusses different aspects of IP neovascularization in atherosclerosis including the potential treatment opportunities to stabilize advanced plaques. Furthermore, we highlight the development of accurate and feasible in vivo imaging modalities for IP neovascularization to prevent acute events.

EXPERT OPINION

Although lack of a valuable animal model of IP neovascularization impeded the investigation of a causal and straightforward link between neovascularization and atherosclerosis, recent evidence shows that vein grafts in ApoE*3 Leiden mice as well as plaques in ApoE(-/-) Fbn1(C1039G+/-) mice are useful models for intraplaque neovessel research. Even though interference with vascular endothelial growth factor (VEGF) signalling has been widely investigated, new therapeutic opportunities have emerged. Cell metabolism, in particular glycolysis and fatty acid oxidation, appears to perform a crucial role in the development of IP neovessels and thereby serves as a promising target.

Fibroblast growth factor signaling in the vasculature

Despite their discovery as angiogenic factors and mitogens for endothelial cells more than 30 years ago, much remains to be determined about the role of fibroblast growth factors (FGFs) and their receptors in vascular development, homeostasis, and disease. In vitro studies show that members of the FGF family stimulate growth, migration, and sprouting of endothelial cells, and growth, migration, and phenotypic plasticity of vascular smooth muscle cells. Recent studies have revealed important roles for FGFs and their receptors in the regulation of endothelial cell sprouting and vascular homeostasis in vivo. Furthermore, recent work has revealed roles for FGFs in atherosclerosis, vascular calcification, and vascular dysfunction. The large number of FGFs and their receptors expressed in endothelial and vascular smooth muscle cells complicates these studies. In this review, we summarize recent studies in which new and unanticipated roles for FGFs and their receptors in the vasculature have been revealed.

Fibroblast growth factors in cardiovascular disease: The emerging role of FGF21

Early detection of risk factors for enhanced primary prevention and novel therapies for treating the chronic consequences of cardiovascular disease are of the utmost importance for reducing morbidity. Recently, fibroblast growth factors (FGFs) have been intensively studied as potential new molecules in the prevention and treatment of cardiovascular disease mainly attributable to metabolic effects and angiogenic actions. Members of the endocrine FGF family have been shown to increase metabolic rate, decrease adiposity, and restore glucose homeostasis, suggesting a multiple metabolic role. Serum levels of FGFs have been associated with established cardiovascular risk factors as well as with the severity and extent of coronary artery disease and could be useful for prediction of cardiovascular death. Furthermore, preclinical investigations and clinical trials have tested FGF administration for therapeutic angiogenesis in ischemic vascular disease, demonstrating a potential role in improving angina and limb function. FGF21 has lately emerged as a potent metabolic regulator with multiple effects that ultimately improve the lipoprotein profile. Early studies show that FGF21 is associated with the presence of atherosclerosis and may play a protective role against plaque formation by improving endothelial function. The present review highlights recent investigations suggesting that FGFs, in particular FGF21, may be useful as markers of cardiovascular risk and may also serve as protective/therapeutic agents in cardiovascular disease.

Inflammation and immunity in diseases of the arterial tree: players and layers

The hypothesis that immunity and inflammation participate in the pathogenesis of vascular diseases has now gained widespread recognition and stimulated work around the globe. Broadening knowledge has extended the recognition of the role of immune and inflammatory mechanisms to all of the layers of the artery, to all levels of the arterial tree, and implicated virtually all arms, cellular players, and effector molecules and pathways involved in these crucial host defenses, that turn against us in disease. We provide here a guide to a compendium series of articles that aimed to look forward and broaden the traditional focus of immunopathogenesis of arterial disease, with the goal of integrating the players and the layers involved. Although the field has advanced remarkably, much remains to be done, and this commentary also aims to highlight some of the gaps that future research should strive to close on the participation of inflammation and immunity in arterial diseases.

Pericoronary adipose tissue: a novel therapeutic target in obesity-related coronary atherosclerosis

Inflammation plays a crucial role in the development and destabilization of atherosclerotic plaques in coronary vessels. Adipose tissue is considered to act in paracrine manner, which modulates a number of physiological and pathophysiological processes. Perivascular adipose tissue has developed specific properties that distinguish it from the fat in other locations. Interestingly, its activity depends on several metabolic conditions associated with insulin resistance and weight gain. Particularly in obesity perivascular fat seems to change its character from a protective to a detrimental one. The present review analyzes literature in terms of the pathophysiology of atherosclerosis, with particular emphasis on inflammatory processes. Additionally, the authors summarize data about confirmed paracrine activity of visceral adipose tissue and especially about pericoronary fat influence on the vascular wall. The contribution of adiponectin, leptin and resistin is addressed. Experimental and clinical data supporting the thesis of outside-to-inside signaling in the pericoronary milieu are further outlined. Clinical implications of epicardial and pericoronary adipose tissue activity are also evaluated. The role of pericoronary adipose tissue in obesity-related atherosclerosis is highlighted. In conclusion, the authors discuss potential therapeutical implications of these novel phenomena, including adipokine imbalance in pericoronary adipose tissue in the setting of obesity, the influence of lifestyle and diet modification, pharmaceutical interventions and the growing role of microRNAs in adipogenesis, insulin resistance and obesity. Key teaching points: • adipose tissue as a source of inflammatory mediators • changes in the vascular wall as a result of outside-to-inside signaling • anatomy, physiology, and clinical implications of epicardial and pericoronary adipose tissue activity • adipokines and their role in obesity-related atherosclerosis • therapeutic perspectives and future directions.

Increased microvascularization and vessel permeability associate with active inflammation in human atheromata

BACKGROUND

Studies have shown the feasibility of imaging plaques with 2-deoxy-2-[(18)F]fluoroglucose (FDG) positron emission tomography and dynamic contrast-enhanced magnetic resonance imaging with inconsistent results. We sought to investigate the relationship between markers of inflammatory activation, plaque microvascularization, and vessel wall permeability in subjects with carotid plaques using a multimodality approach combining FDG positron emission tomography, dynamic contrast-enhanced magnetic resonance imaging, and histopathology.

METHODS AND RESULTS

Thirty-two subjects with carotid stenoses underwent noninvasive imaging with FDG positron emission tomography and dynamic contrast-enhanced magnetic resonance imaging, 46.9% (n=15) before carotid endarterectomy. We measured FDG uptake (target:background ratio [TBR]) by positron emission tomography and K(trans) (reflecting microvascular permeability and perfusion) by magnetic resonance imaging and correlated imaging with immunohistochemical markers of macrophage content (CD68), activated inflammatory cells (major histocompatibility complex class II), and microvessels (CD31) in plaque and control regions. TBR and K(trans) correlated significantly with tertiles of CD68(+) (P=0.009 and P=0.008, respectively), major histocompatibility complex class II(+) (P=0.003 and P<0.001, respectively), and CD31(+) (P=0.004 and P=0.008, respectively). Regions of plaques were associated with increased CD68(+) (P=0.002), major histocompatibility complex class II(+) (P=0.002), CD31(+) (P=0.02), TBR (P<0.0001), and K(trans) (P<0.0001), as compared with those without plaques. Microvascularization correlated with macrophage content (rs=0.52; P=0.007) and inflammatory activity (rs=0.68; P=0.0001) and TBR correlated with K(trans) (rs=0.53; P<0.0001). In multivariable mixed linear regression modeling, TBR remained independently associated with K(trans) (β[SE], 2.68[0.47]; P<0.0001).

CONCLUSIONS

Plaque regions with active inflammation, as determined by macrophage content and major histocompatibility complex class II expression, showed increased FDG uptake, which correlated with increased K(trans) and microvascularization. The correlation between K(trans) and TBR was moderate, direct, highly significant, and independent of clinical symptoms and plaque luminal severity.

The effect of physical activity or exercise on key biomarkers in atherosclerosis--a systematic review

OBJECTIVE

This systematic review aimed to summarize published papers on the effect of physical activity (PA)/exercise on key atherosclerotic factors in patients with risk factors for or established cardiovascular disease (CVD).

METHODS

Studies involving PA and cytokines, chemokines, adhesion molecules, CRP and angiogenic factors were searched for in Medline and Cochrane library. Original human studies of more than 2 weeks of PA intervention were included. Study quality was assessed according to the GRADE system of evidence.

RESULTS

Twenty-eight papers fulfilled the inclusion criteria. PA decreases the cytokines, tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6), and interferon-y IFN-y (high, moderate and low evidence, respectively). The effect of PA on chemokines; stromal derived factor-1 (SDF-1), interleukin-8 (IL-8) (insufficient evidence) and monocyte chemoattractant protein-1 (MCP-1) (low evidence) was inconclusive. Aerobic exercise decreased the adhesion molecules, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) (moderate and high evidence, respectively), while effects of PA on E- and P-selectin were inconclusive. PA decreases C-reactive protein (CRP) (high evidence). The angiogenic actors, endothelial progenitor cells (EPCs) are increased (high evidence) and VEGF is decreased (moderate evidence) by PA. The effect of PA on these factors seems to depend on the type and duration of exercise intervention and patient factors, such as presence of ischemia.

CONCLUSION

As presented in this review, there is a high level of evidence that physical activity positively affects key players in atherosclerosis development. These effects could partly explain the scientifically proven anti-atherogenic effects of PA, and do have important clinical implications.

The role IL-1 in tumor-mediated angiogenesis

Tumor angiogenesis is one of the hallmarks of tumor progression and is essential for invasiveness and metastasis. Myeloid inflammatory cells, such as immature myeloid precursor cells, also termed myeloid-derived suppressor cells (MDSCs), neutrophils, and monocytes/macrophages, are recruited to the tumor microenvironment by factors released by the malignant cells that are subsequently “educated” in situ to acquire a pro-invasive, pro-angiogenic, and immunosuppressive phenotype. The proximity of myeloid cells to endothelial cells (ECs) lining blood vessels suggests that they play an important role in the angiogenic response, possibly by secreting a network of cytokines/chemokines and inflammatory mediators, as well as via activation of ECs for proliferation and secretion of pro-angiogenic factors. Interleukin-1 (IL-1) is an “alarm,” upstream, pro-inflammatory cytokine that is generated primarily by myeloid cells. IL-1 initiates and propagates inflammation, mainly by inducing a local cytokine network and enhancing inflammatory cell infiltration to affected sites and by augmenting adhesion molecule expression on ECs and leukocytes. Pro-inflammatory mediators were recently shown to play an important role in tumor-mediated angiogenesis and blocking their function may suppress tumor progression. In this review, we summarize the interactions between IL-1 and other pro-angiogenic factors during normal and pathological conditions. In addition, the feasibility of IL-1 neutralization approaches for anti-cancer therapy is discussed.

A new synthetic FGF receptor antagonist inhibits arteriosclerosis in a mouse vein graft model and atherosclerosis in apolipoprotein E-deficient mice

Objective

The role of fibroblast growth factors (FGFs) in the development of vascular diseases remains incompletely understood. The objective of this study was to examine the effects of a new small-molecule multi-FGF receptor blocker with allosteric properties, SSR128129E, on neointimal proliferation after a vein graft procedure in mice and on the development of atherosclerosis in atherosclerosis-prone apolipoprotein E (apoE)-deficient mice.

Methods and Results

Vein grafts were performed in 3 month-old male C57BL6 mice. Segments of the vena cava were interposed at the level of the carotid artery. In SSR128129E (50 mg/kg/d)-treated animals, a dramatic decrease in neointimal proliferation was observed 2 and 8 weeks after the graft (72.5 %, p<0.01, and 47.8 %, p<0.05, respectively). Four-week old male apoE-deficient mice were treated with SSR128129E (50 mg/kg/d) for 3 and 5 months in comparison with a control group. SSR128129E treatment resulted in a reduction of lesion size in the aortic sinus (16.4 % (ns) at 3 months and 42.9 % (p<0.01) at 5 months, without any change in serum lipids. SSR128129 significantly reduced FGFR2 mRNA levels in the aortic sinus (p<0.05, n=5-6), but did not affect the mRNA expression levels of other FGF receptors or ligands.

Conclusion

These studies indicate that FGFs have an important role in the development of vascular diseases like atherosclerosis and graft arteriosclerosis. These data suggest that inhibition of FGF receptors by compounds like SSR128129E might be useful as a new therapeutic approach for these vascular pathologies.

MicroRNAs as pharmacological targets in endothelial cell function and dysfunction

Endothelial cell dysfunction is a term which implies the dysregulation of normal endothelial cell functions, including impairment of the barrier functions, control of vascular tone, disturbance of proliferative, migratory and morphogenic capacities of endothelial cells, as well as control of leukocyte trafficking. MicroRNAs are short non-coding RNAs that have emerged as critical regulators of gene expression acting predominantly at the post-transcriptional level. This review summarizes the latest insights in the identification of endothelial-specific microRNAs and their targets, as well as their roles in controlling endothelial cell functions in both autocrine and paracrine manner. In addition, we discuss the therapeutic potential for the treatment of endothelial cell dysfunction and associated vascular pathophysiological conditions.

Janus-like role of fibroblast growth factor 2 in arteriosclerotic coronary artery disease: atherogenesis and angiogenesis

Angiogenic stimulation is a promising new strategy for treating patients with arteriosclerotic coronary artery disease. This strategy aims to ameliorate cardiac function by improving myocardial perfusion and lowering the risk of myocardial infarction. However, angiogenesis may contribute to the growth of atherosclerotic lesions. Atherogenesis is also a potential side effect of angiogenic therapy. Early clinical trials were performed using fibroblast growth factor 2 (FGF2) protein, which enhances the formation of new collateral vessels to reduce ischaemic symptoms. Conversely, angiogenic stimulation by FGF2 is a dilemma because it could cause negative angiogenic effects, such as atherosclerosis. Thus far, clinical trials in patients with recombinant FGF2 protein therapy have not yet yielded undisputable beneficial effects. Future trials should determine whether an improvement can be obtained in patients with coronary artery disease using a combination of FGF2 and other growth factors or a combination of the FGF2 gene and stem cell therapy. This review summarises the multiple roles of FGF2 in the progression of atherosclerosis, its effect on pro-angiogenesis and improvement of cardiac function in coronary artery disease, and the potentially unfavourable effect of angiogenesis on the prevention and treatment of atherogenesis.

Adventitial vasa vasorum arteriosclerosis in abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a common disease among elderly individuals. However, the precise pathophysiology of AAA remains unknown. In AAA, an intraluminal thrombus prevents luminal perfusion of oxygen, allowing only the adventitial vaso vasorum (VV) to deliver oxygen and nutrients to the aortic wall. In this study, we examined changes in the adventitial VV wall in AAA to clarify the histopathological mechanisms underlying AAA. We found marked intimal hyperplasia of the adventitial VV in the AAA sac; further, immunohistological studies revealed proliferation of smooth muscle cells, which caused luminal stenosis of the VV. We also found decreased HemeB signals in the aortic wall of the sac as compared with those in the aortic wall of the neck region in AAA. The stenosis of adventitial VV in the AAA sac and the malperfusion of the aortic wall observed in the present study are new aspects of AAA pathology that are expected to enhance our understanding of this disease.

Immunohistochemical study of the growth factors, aFGF, bFGF, PDGF-AB, VEGF-A and its receptor (Flk-1) during arteriogenesis

Growth factors are viewed as main arteriogenic stimulators for collateral vessel growth. However, the information about their native expression and distribution in collateral vessels is still limited. This study was designed to profile expression of acidic and basic FGF, platelet-derived growth factor (PDGF-AB) and vascular endothelial growth factor (VEGF-A) and its receptor, fetal liver kinase-1 (Flk-1) during arteriogenesis by confocal immunofluorescence in both dog ameroid constrictor model and rabbit arteriovenous shunt model of arteriogenesis. We found that: (1) in normal arteries (NA) in dog heart, aFGF, bFGF, and PDGF-AB all were mainly expressed in endothelial cells (EC) and media smooth muscle cells (SMC), but the expression of aFGF was very weak, with those of the other two being moderate; (2) in collateral arteries (CAs), aFGF, bFGF, and PDGF-AB all were significantly upregulated (P < 0.05); they were present in all the layers of the vascular wall and were 2.1, 1.7, and 1.9 times higher than that in NA, respectively; and (3) in NA in rabbit hind limb, VEGF-A was absent, Flk-1 was only weakly present in endothelial cells, but in one week CAs VEGF-A and Flk-1 were significantly increased in both shunt and ligation sides; this was more evident in the shunt-side CAs, 2.3, and 2 times higher than that in the ligation side, respectively. In conclusion, our data demonstrate for the first time that growth factors, aFGF, bFGF, and PDGF-AB are significantly upregulated in collateral vessels in dog heart, and enhanced VEGF-A and its receptor, Flk-1, are associated with rapid and lasting increased shear stress. These findings suggest that endogenous production of growth factors could be an important factor promoting collateral vessel growth.

Metabolism and actions of conjugated linoleic acids on atherosclerosis-related events in vascular endothelial cells and smooth muscle cells

Conjugated linoleic acids (CLAs) are biologically highly active lipid compounds that have attracted great scientific interest due to their ability to cause either inhibition of atherosclerotic plaque development or even regression of pre-established atherosclerotic plaques in mice, hamsters and rabbits. The underlying mechanisms of action, however, are only poorly understood. Since cell culture experiments are appropriate to gain insight into the mechanisms of action of a compound, the present review summarizes data from cell culture studies about the metabolism and the actions of CLAs on atherosclerosis-related events in endothelial cells (ECs) and smooth muscle cells (SMCs), which are important cells contributing to atherosclerotic lesion development. Based on these studies, it can be concluded that CLAs exert several beneficial actions including inhibition of inflammatory and vasoactive mediator release from ECs and SMCs, which may help explain the anti-atherogenic effect of CLAs observed in vivo. The observation that significant levels of CLA metabolites, which have been reported to have significant biological activities, are well detectable in ECs and SMCs indicates that the anti-atherogenic effects observed with CLAs are presumably mediated not only by CLAs themselves but also by their metabolites.

Polymorphisms in the promoter region of the basic fibroblast growth factor gene are not associated with myocardial infarction in a Slovene population with type 2 diabetes

Basic fibroblast growth factor (bFGF) is a multifunctional growth factor that may play a significant role in atherosclerotic vascular complications in patients with type 2 diabetes. This study was designed to investigate the association between genetic polymorphisms (-553 T/A, -834 T/A and -921 C/G) in the promoter region of the bFGF gene and myocardial infarction (MI) in 443 patients with type 2 diabetes (149 with MI and 294 with no history of coronary artery disease). The -553 T/A, -834 T/A and -921 C/G polymorphisms of the bFGF gene were found not to be risk factors for MI in patients with type 2 diabetes. The impact of bFGF gene polymorphisms on serum bFGF levels was also investigated and significantly higher serum levels of bFGF were demonstrated in diabetes patients with the TA genotype of the -553 T/A polymorphism compared with diabetes patients with the TT wild type genotype (9.0 +/- 5.6 ng/l versus 3.0 +/- 1.9 ng/l, respectively). Thus, the tested bFGF gene polymorphisms cannot be used as genetic markers for MI in diabetic Caucasians.

FRS2 via fibroblast growth factor receptor 1 is required for platelet-derived growth factor receptor beta-mediated regulation of vascular smooth muscle marker gene expression

Vascular smooth muscle cells (VSMC) exhibit phenotypic plasticity and change from a quiescent contractile phenotype to a proliferative synthetic phenotype during physiological arteriogenesis and pathological conditions such as atherosclerosis and restenosis. Platelet-derived growth factor (PDGF)-BB is a potent inducer of the VSMC synthetic phenotype; however, much less is known about the role of fibroblast growth factor-2 (FGF2) in this process. Here, we show using signal transduction mutants of FGF receptor 1 (FGFR1) expressed in rat VSMC that the adaptor protein FRS2 is essential for FGFR1-mediated phenotypic modulation and down-regulation of VSMC smooth muscle alpha-actin (SMA) gene expression. In addition, we show that PDGF-BB and FGF2 act synergistically to induce cell proliferation and down-regulate SMA and SM22alpha in VSMC. Furthermore, we show that PDGF-BB induces tyrosine phosphorylation of FGFR1 and that this phosphorylation is mediated by PDGF receptor-beta (PDGFRbeta), but not c-Src. We demonstrate that FRS2 co-immunoprecipitates with PDGFRbeta in a complex that requires FGFR1 and that both the extracellular and the intracellular domains of FGFR1 are required for association with PDGFRbeta, whereas the cytoplasmic domain of FGFR1 is required for FRS2 association with the FGFR1-PDGFRbeta complex. Knockdown of FRS2 in VSMC by RNA interference inhibited PDGF-BB-mediated down-regulation of SMA and SM22alpha without affecting PDGF-BB mediated cell proliferation or ERK activation. Together, these data support the notion that PDGFRbeta down-regulates SMA and SM22alpha through formation of a complex that requires FGFR1 and FRS2 and prove novel insight into VSMC phenotypic plasticity.

Activation Transcription Factor-4 Induced by Fibroblast Growth Factor-2 Regulates Vascular Endothelial Growth Factor-A Transcription in Vascular Smooth Muscle Cells and Mediates Intimal Thickening in Rat Arteries Following Balloon Injury

Activation transcription factor (ATF)-4 is a member of the ATF/CREB family of basic leucine zipper transcription factors that regulates cellular responses to a variety of stresses. The role of ATF-4 in smooth muscle cells of the vessel wall is completely unknown. Here, we show that ATF-4 expression is induced in smooth muscle cells in response to injury, both in vitro using a model of mechanical injury and in the media of balloon-injured rat carotid arteries. We demonstrate that ATF-4 is activated by fibroblast growth factor (FGF)-2, an injury-induced mitogen, through the phosphatidylinositol 3-kinase pathway. Injury also activates vascular endothelial growth factor (VEGF)-A, whose expression is stimulated by ATF-4 overexpression and exposure to FGF-2. FGF-2 induces ATF-4 binding to a recognition element located in the VEGF-A gene at +1767 bp and luciferase reporter gene expression dependent on this site. Moreover, ATF-4 knockdown with small interfering RNA or ATF-4 deficiency ameliorates FGF-2–inducible VEGF-A expression. Intraluminal delivery of ATF-4 small interfering RNA in rat carotid arteries blocks balloon injury–inducible ATF-4 and VEGF-A expression after 4 hours and intimal thickening after 14 days. These findings reveal, for the first time, the induction of ATF-4 by both vascular injury and FGF-2. ATF-4 serves as a conduit for the inducible expression of 1 growth factor by another during the process of intimal thickening.

Secretion without Golgi

A growing number of proteins devoid of signal peptides have been demonstrated to be released through the non-classical pathways independent of endoplasmic reticulum and Golgi. Among them are two potent proangiogenic cytokines FGF1 and IL1alpha. Stress-induced transmembrane translocation of these proteins requires the assembly of copper-dependent multiprotein release complexes. It involves the interaction of exported proteins with the acidic phospholipids of the inner leaflet of the cell membrane and membrane destabilization. Not only stress, but also thrombin treatment and inhibition of Notch signaling stimulate the export of FGF1. Non-classical release of FGF1 and IL1alpha presents a promising target for treatment of cardiovascular, oncologic, and inflammatory disorders.

Inflammatory angiogenesis in atherogenesis--a double-edged sword

The adventitia and the outer layers of media of an atherosclerosis-prone arterial wall are vascularized by vasa vasorum. Upon growth of an atherosclerotic lesion in the intima, neovascular sprouts originating from the adventitial vasa vasorum enter the lesion, the local proangiogenic micromilieu in the lesion being created by intramural hypoxia, by increased intramural oxidant stress, and by inflammatory cell infiltration (macrophages, T cells and mast cells). The angiogenic factors present in the lesions include various growth factors, chemokines, cytokines, proteinases, and several other factors possessing direct or indirect angiogenic activities, while the current list of antiangiogenic factors is smaller. An imbalance between endogenous inducers and inhibitors of angiogenesis, with a predominance of the former ones, is essential for the development of neovessels during the progression of the lesion. By providing oxygen and nutrients to the cells of atherosclerotic lesions, neovascularization initially tends to prevent cellular death and so contributes to plaque growth and stabilization. However, the inflammatory cells may induce rupture of the fragile neovessels, and so cause intraplaque hemorrhage and ensuing plaque destabilization. Pharmacological inhibition of angiogenesis in atherosclerotic plaques with ensuing inhibition of lesion progression has been achieved in animal models, but clinical studies aiming at regulation of angiogenesis in the atherosclerotic arterial wall can be designed only after we have reached a firm conclusion about the role of angiogenesis at various stages of lesion development--good or bad.

Fibroblast growth factor 1 gene and hypertension: from the quantitative trait locus to positional analysis

BACKGROUND

The distal portion of the long arm of chromosome 5 is linked to hypertension and contains functional candidate blood pressure-regulating genes.

METHODS AND RESULTS

Tightening the grid of microsatellite markers under this quantitative trait locus in the Silesian Hypertension Study (629 individuals from 207 Polish hypertensive families) provided enhanced support for linkage of this region to blood pressure (maximal Z=3.51, P=0.0002). The fine mapping, comparative genomics, and functional prioritization identified fibroblast growth factor 1 gene (FGF1) as the positional candidate. Linkage disequilibrium mapping based on 51 single nucleotide polymorphisms spanning the locus showed no overlap between 3 independent haploblocks of FGF1 and the adjacent extragenic chromosomal regions. Single and multilocus family-based analysis revealed that genetic variation within FGF1 haploblock 1 was associated with hypertension and identified a common intronic single nucleotide polymorphism, rs152524, as the major driver of this association (P=0.0026). Real-time quantitative polymerase chain reaction and Western blotting analysis of renal tissue obtained from subjects undergoing unilateral nephrectomy showed an increase in both mRNA and protein FGF1 expression in hypertensive patients compared with normotensive controls. Renal immunohistochemistry revealed that FGF1 was expressed exclusively within the glomerular endothelial and mesangial cells.

CONCLUSIONS

Our data demonstrate that genetic variation within FGF1 cosegregates with elevated blood pressure in hypertensive families and that this association is likely to be mediated by upregulation of renal FGF1 expression. The results of our study will need to be replicated in other cohorts.

Suppression of growth factor expression and human vascular smooth muscle cell growth by small interfering RNA targeting EGR-1

Smooth muscle cell (SMC) proliferation and migration are key processes that occur in the reparative response to injury after percutaneous coronary intervention and in failed bypass grafts for the treatment of atherosclerosis. In the present study, we generated novel synthetic small interfering RNA (siRNA) molecules targeting the coding region of human early growth response-1 (EGR-1) mRNA that attenuate the expression of EGR-1 and that of fibroblast growth factor-2 (FGF-2) and granulocyte-colony stimulating factor (G-CSF). These agents suppressed SMC proliferation in a dose-dependent and non-toxic manner and blocked SMC regrowth from the wound edge following mechanical injury in vitro. In contrast, the scrambled counterpart did not inhibit SMC proliferation, EGR-1 protein expression or SMC regrowth after injury. These findings demonstrate that EGR-1 siRNA can serve as inhibitors of SMC proliferation and wound repair suggesting that these agents may potentially be useful in the control of vascular proliferative disorders.

Tumour-derived fibroblast growth factor-2 exerts lymphangiogenic effects through Akt/mTOR/p70S6kinase pathway in rat lymphatic endothelial cells

Fibroblast growth factor-2 (FGF-2) has been shown to induce both angiogenesis and lymphangiogenesis in the mouse corneum; however, the signalling mechanism underlying FGF-2-induced lymphangiogenesis remains unknown. Here we investigated the effect of FGF-2 on newly developed temperature-sensitive rat lymphatic endothelial (TR-LE) cells. The supernatant of PC-3 prostate cancer cells facilitated tube-like formation in TR-LE cells, and formation was inhibited by neutralising antibodies against FGF-2. The addition of FGF-2 stimulated tube-like formation as well as proliferation and chemotactic migration of TR-LE cells. Blockade of the Akt signalling pathway by LY294002 abolished the elongation of tubes induced by FGF-2, whereas inhibition of the extracellular signal-regulated kinase (ERK) signalling pathway had no effect. Rapamycin abrogated the phosphorylation of p70S6kinase and consistently inhibited the formation of tubes induced by FGF-2. Furthermore, tube-like formation induced by the supernatant of PC-3 cells was inhibited by LY294002 or rapamycin. These data suggest that FGF-2 exerts lymphangiogenic effects by activating the Akt/mammalian target of rapamycin (mTOR)/p70S6kinase pathway in lymphatic endothelial cells, and that the pathway provides a potent target for tumour lymphangiogenesis.

Endothelial cells' activation and apoptosis induced by a subset of antibodies against human cytomegalovirus: relevance to the pathogenesis of atherosclerosis

BACKGROUND

Human cytomegalovirus (hCMV) is involved in the pathogenesis of atherosclerosis. We have previously shown in patients with atherosclerosis that antibodies directed against the hCMV-derived proteins US28 and UL122 are able to induce endothelial cell damage and apoptosis of non-stressed endothelial cells through cross-rection with normally expressed surface molecules. Our aim was to dissect the molecular basis of such interaction and to investigate mechanisms linking innate immunity to atherosclerosis.

METHODOLOGY/PRINCIPAL FINDINGS

We analysed the gene expression profiles in endothelial cells stimulated with antibodies affinity-purified against either the UL122 or the US28 peptides using the microarray technology. Microarray results were validated by quantitative PCR and by detection of proteins in the medium. Supernatant of endothelial cells incubated with antibodies was analysed also for the presence of Heat Shock Protein (HSP)60 and was used to assess stimulation of Toll-Like Receptor-4 (TLR4). Antibodies against UL122 and US28 induced the expression of genes encoding for adhesion molecules, chemokines, growth factors and molecules involved in the apoptotis process together with other genes known to be involved in the initiation and progression of the atherosclerotic process. HSP60 was released in the medium of cells incubated with anti-US28 antibodies and was able to engage TLR4.

CONCLUSIONS/SIGNIFICANCE

Antibodies directed against hCMV modulate the expression of genes coding for molecules involved in activation and apoptosis of endothelial cells, processes known to play a pivotal role in the pathogenesis of atherosclerosis. Moreover, endothelial cells exposed to such antibodies express HSP60 on the cell surface and release HSP60 in the medium able to activate TLR4. These data confirm that antibodies directed against hCMV-derived proteins US28 and UL122 purified from patients with coronary artery disease induce endothelial cell damage and support the hypothesis that hCMV infection may play a crucial role in mediating the atherosclerotic process.

Plaque neovascularization and antiangiogenic therapy for atherosclerosis

The concept that neovascularization of the vessel wall may play a fundamental role in the pathophysiology of atherosclerosis was proposed more than a century ago. In recent years, supportive experimental evidence for this hypothesis (such as the finding that neointimal microvessels may increase delivery of cellular and soluble lesion components to the vessel wall) has been underscored by clinical studies associating plaque angiogenesis with more rapidly progressive high-grade disease. Attention has also focused on a possible role for microvessel-derived intraplaque hemorrhage in the development of acute lesion instability. The interest of clinicians in this phenomenon has been spurred by the potential to target vessel wall neovascularization with angiogenesis inhibitors, a therapeutic approach that has been associated with impressive reductions in plaque progression in animal models of vascular disease. The rationale for pursuing an "antiangiogenic" strategy in the treatment of patients with vascular disease, and a framework for further preclinical evaluation of such therapy, is presented here.

Metabolic alterations in cultured mouse fibroblasts induced by an inhibitor of the tyrosine kinase receptor Fibroblast Growth Factor Receptor 1

Proton nuclear magnetic resonance (NMR) spectroscopy was used to identify and quantify the metabolites present in cultured mouse fibroblast cells 3T6 in their native state and after treatment with PD166866, an inhibitor of the fibroblast growth factor receptor. Cell extracts were prepared according to the Bligh-Dyer protocol which prevents artifacts deriving from the chemical demolition of macromolecules. Also the growth medium was subjected to the same extraction procedure. The NMR approach made possible the identification and quantification of about 40 different metabolites at nanomoles/mg of protein level: the biological relevance of the variation of some metabolite levels is discussed. Our experimental procedure offers a prospective method for the evaluation of variations of the metabolic profile deriving from different biochemical treatments of these cells.

A functional SNP in ITIH3 is associated with susceptibility to myocardial infarction

Myocardial infarction (MI) results from complex interactions of multiple genetic and environmental factors. To disclose genetic backgrounds of MI, we performed a large-scale, case-control association study using 52,608 gene-based single-nucleotide polymorphism (SNP) markers, and identified a candidate SNP located on chromosome 3p21.2-p21.1. Subsequent linkage-disequilibrium mapping indicated very significant association between MI and a SNP in exon 2 of the inter-alpha (globulin) inhibitor 3 gene (ITIH3; chi(2) = 24.88, P = 6.1 x 10(-7), 3,353 affected individuals versus 3,807 controls). In vitro functional analyses showed that this SNP enhanced the transcriptional level of the ITIH3 gene. Furthermore, we found expression of the ITIH3 protein in the vascular smooth muscle cells and macrophages in the human atherosclerotic lesions, suggesting ITIH3 SNP to be a novel genetic risk factor of MI.

Angiogenesis in atherosclerosis: gathering evidence beyond speculation

PURPOSE OF REVIEW

The present review summarizes evidence for several functions of neovascularization in plaque growth that sustain perfusion beyond limits of diffusion from the artery lumen and outer adventitial vasa vasorum, deposit proatherogenic plasma molecules, recruit immune cells and progenitors, and promote intraplaque hemorrhage. Recent approvals of antiangiogenesis drugs for clinical use in cancer and macular degeneration improve the feasibility of testing whether such agents inhibit plaque angiogenesis and incidental atherosclerosis.

RECENT FINDINGS

Improvements in large and small animal models of atherosclerosis and knowledge of the molecular regulation of angiogenesis in development and disease have advanced understanding of plaque angiogenesis. Genetic modifications of angiogenesis molecules in mouse strains susceptible to atherosclerosis provide experimental means to identify native molecules that regulate plaque angiogenesis. Studies of plaque angiogenesis are aided by micro-computed tomography techniques that image vasa vasorum anatomy in relation to the atheroma.

SUMMARY

Greater knowledge of plaque angiogenesis regulation is needed to design treatments that target the most critical regulatory pathways. Evolutions in angiogenesis inhibitor treatments for cancer and other diseases call for a need to understand the distinct cardiovascular profiles of different agents to rationally combine agents for optimal selectivity and efficacy in the intended vascular bed.

Angiogenesis in Atherogenesis

Atherogenesis is the pathobiological process, which underlies atherosclerotic cardiovascular disease and evolves in the 3 stages of initiation, progression, and complication to clinical significance. Of note, this process is associated with neovascularization, and it was not until recently that the implications of angiogenesis in atherogenesis were delineated. This article gives an updated overview on this topic and briefly reflects on the similarities with neovessel formation in carcinogenesis.

Alternatively spliced FGFR-1 isoforms differentially modulate endothelial cell activation of c-YES

Ligand activation of fibroblast growth factor receptor-1 (FGFR-1) induces an angiogenic response following activation of multiple intracellular signaling substrates, including the Src family of nonreceptor tyrosine kinases (SFK). However, the direct association between FGFR-1 and SFK and the involvement of SFK in FGFR-1-dependent cell proliferation have been controversial. Structural variants of FGFR-1 are generated by alternative splicing which results in two major isoforms, containing either three (FGFR-1alpha) or two (FGFR-1beta) immunoglobulin-like domains in the extracellular region. To determine whether alternatively spliced FGFR-1 isoforms differentially activate SFK, we have examined FGF receptor-negative endothelial cells stably transfected with human cDNA encoding either FGFR-1alpha or FGFR-1beta. Transient activation of c-YES, the predominant SFK expressed in these endothelial cells, was restricted to FGFR-1beta transfectants following exposure to acidic fibroblast growth factor (FGF-1). Co-immunoprecipitation studies revealed that c-YES directly associated with FGFR-1beta. The Src homology (SH)2 domain (and not the SH3 domain) of c-YES was able to recognize tyrosine phosphorylated FGFR-1beta. FGFR-1beta-specific activation of c-YES was accompanied by its association with and activation of cortactin. FGF-1 treatment of both FGFR-1alpha and FGFR-1beta transfectants induced SFK-independent cellular proliferation and growth in low density cultures. At high density, under both anchorage-dependent and -independent conditions, FGF-1 failed to induce proliferation and growth of FGFR-1alpha transfectants. In contrast, FGF-1 induced proliferation, growth, and formation of cord-like structures in high density cultures of FGFR-1beta transfectants in an SFK-dependent manner. In vitro cord formation on Matrigel was restricted to FGFR-1beta transfectants in an SFK-dependent manner. Formation of vascular structures in vivo was limited to endothelial cells transfected with FGFR-1beta. Collectively, these results emphasize the roles of alternatively spliced FGFR-1 structural isoforms and activation of SFK as modulators of endothelial cell growth during the formation of neovascular structures.

Vascular endothelium and atherosclerosis

Atherosclerosis depends critically on altered behavior of the intrinsic cells of the artery wall, the endothelial cells and smooth muscle cells, and inflammatory leukocytes that join them in the arterial intima during the atherogenic process. The homeostatic properties of the normal endothelium contribute importantly to maintenance of aspects of arterial health including the appropriate regulation of blood flow, a basal anti-inflammatory state, promotion of fibrinolysis while opposing blood coagulation, and control of the balance of cellular proliferation and death. Alterations in these endothelial homeostatic mechanisms contribute critically to atherogenesis, the progression of this disease, and ist complications. Recent advances have highlighted novel molecular mechanisms that regulate the atheroprotective functions of normal endothelial cells that go awry during atherogenesis. Therapeutic strategies that alter the course of atherosclerosis may act by combating endothelial dysfunction.