Activation of nuclear factor-kappa B significantly contributes to lumen loss in a rabbit iliac artery balloon angioplasty model

Impact of intracoronary nicorandil before stent deployment in patients with acute coronary syndrome undergoing percutaneous coronary intervention

The present study aimed to clarify the effect of bolus intracoronary nicorandil on inflammatory, oxidative and adherent indicators in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). This randomized controlled trial (RCT) was performed to detect the inflammation and oxidative stress in intracoronary blood both before and after PCI. In total, 65 consecutive patients undergoing PCI were classified into a nicorandil therapy group (n=32) or a placebo group (n=33). All procedures were performed at Shandong University Qilu Hospital, China, during the period from March, 2016 to May, 2017. Intracoronary blood from patients who received nicorandil therapy during PCI showed no change in soluble CD40 ligand (sCD40L) concentration (1.86±0.08 vs. 1.90±0.09 ng/ml, P=0.12) but a significant increase was noted in the control group (1.87±0.17 vs. 2.82±0.26 ng/ml, P<0.01). This indicated a relative reduction in sCD40L level after PCI in the nicorandil group. We further demonstrated an increase in superoxide dismutase (SOD) activity (29.37±0.81 vs. 31.03±0.60 U/ml, P<0.001) and a reduction in lipid peroxidation (3.84±0.99 vs. 4.23±0.13 U/ml, P=0.001) in the nicorandil group but observed no change in the placebo group. ICAM-1 levels showed no change in the nicorandil group (69.54±6.89 vs. 72.01±8.25 ng/ml, P=0.83) but a significant increase in the control group after PCI in intracoronary blood (56.57±4.96 vs. 76.81±6.88 ng/ml, P=0.002). No changes were found in hs-CRP, TNFα and sVCAM-1 levels in coronary blood for both groups before and after PCI in ACS patients. Our findings demonstrate that intracoronary bolus nicorandil therapy has a significant effect on the inhibition of inflammatory indicators and oxidative stress in patients with ACS during PCI. This suggests a possible medical application of nicorandil for reducing inflammation and oxidative stress.

Pro-resolving lipid mediators in the resolution of neointimal hyperplasia pathogenesis in atherosclerotic diseases

INTRODUCTION

Despite advances in drug eluting technologies, neointimal hyperplasia (NIH) and restenosis still plagues endovascular therapy in atherosclerotic diseases. By appreciating atherosclerosis and NIH as complex inflammatory processes, specialized pro-resolving mediators (SPMs) are a superfamily of endogenous unsaturated fatty-acid derived lipids with the potential for inflammatory resolution. Areas covered: Inquiry into SPMs in this context is a novel approach and is the focus of this review, with emphasis on our understanding with NIH. Prior mechanistic understandings of SPM deficiency with atherosclerosis has offered insight, as well as the complexity and diversity of the SPM superfamily. Therapeutic investigation using SPMs to combat NIH is also evaluated here. Expert commentary: Endogenous deficiency of SPMs synthesis by 12/15-lipoxygenase underlies resolution deficits in atherosclerosis and NIH. Upstream PDGF inhibition by SPMs, most notably RvD1 and LXA4, confers a multifactorial attenuation of NIH that involves interconnected anti-inflammatory efforts, most notably switch pro-resolving smooth muscle cells (vSMCs) and macrophages. The ALX/FPR2 is one receptor system identified on vSMCs that interacts with these SPMs to promote NIH resolution. Therapeutically, while shown to be promising with less stent burden or cytotoxicity, SPMs must be balanced by necessary mechanistic, pharmacokinetic and anatomical considerations.

Hindlimb Ischemia Impairs Endothelial Recovery and Increases Neointimal Proliferation in the Carotid Artery

Peripheral ischemia is associated with higher degree of endothelial dysfunction and a worse prognosis after percutaneous coronary interventions (PCI). However, the role of peripheral ischemia on vascular remodeling in remote districts remains poorly understood. Here we show that the presence of hindlimb ischemia significantly enhances neointima formation and impairs endothelial recovery in balloon-injured carotid arteries. Endothelial-derived microRNAs are involved in the modulation of these processes. Indeed, endothelial miR-16 is remarkably upregulated after vascular injury in the presences of hindlimb ischemia and exerts a negative effect on endothelial repair through the inhibition of RhoGDIα and nitric oxide (NO) production. We showed that the repression of RhoGDIα by means of miR-16 induces RhoA, with consequent reduction of NO bioavailability. Thus, hindlimb ischemia affects negative carotid remodeling increasing neointima formation after injury, while systemic antagonizzation of miR-16 is able to prevent these negative effects.

Acute and long-term effect of percutaneous coronary intervention on serially-measured oxidative, inflammatory, and coagulation biomarkers in patients with stable angina

To derive insights into the temporal changes in oxidative, inflammatory and coagulation biomarkers in patients with stable angina undergoing percutaneous coronary intervention (PCI). PCI is associated with a variety of biochemical and mechanical stresses to the vessel wall. Oxidized phospholipids are present on plasminogen (OxPL-PLG) and potentiate fibrinolysis in vitro. We recently showed that OxPL-PLG increase following acute myocardial infarction, suggesting that they are involved in atherothrombosis. Plasma samples were collected before, immediately after, 6 and 24 h, 3 and 7 days, and 1, 3, and 6 months after PCI in 125 patients with stable angina undergoing uncomplicated PCI. Plasminogen levels, OxPL-PLG, and an array of 16 oxidative, inflammatory and coagulation biomarkers were measured with established assays. OxPL-PLG and plasminogen declined significantly immediately post-PCI, rebounded to baseline, peaked at 3 days and slowly returned to baseline by 6 months (p < 0.0001 by ANOVA). The temporal trends to maximal peak in biomarkers were as follows: immediately post PCI: OxPL-apoB and lipoprotein (a); Day 1-the inflammatory biomarker IL-6; Day 3-CRP and coagulation biomarkers OxPL-PLG, plasminogen and tissue plasminogen activity; Day 3 to 7-plasminogen activator inhibitor activity, and complement factor H binding to malondialdehyde-LDL and MDA-LDL IgG; Day 7-30 MDA-LDL IgM, CuOxLDL IgM, and ApoB-IC IgM and IgG; >30 days uPA activity, uPA antigen, CuOxLDL IgG and peptide mimotope to MDA-LDL. Most of the biomarkers trended to baseline by 6 months. PCI results in a specific, temporal sequence of changes in plasma biomarkers. These observations provide insights into the effects of iatrogenic barotrauma and plaque disruption during PCI and suggest avenues of investigation to explain complications of PCI and development of targeted therapies to enhance procedural success.

ERK2 and Akt are negative regulators of insulin and Tumor Necrosis Factor-α stimulated VCAM-1 expression in rat aorta endothelial cells

Background

Diabetes is quickly becoming the most widespread disorder in the Western world. Among the most prevalent effects of diabetes is atherosclerosis, which in turn is driven in part by inflammation. Both insulin and Tumor Necrosis Factor-alpha (TNFα) increase the presence of Vascular Cellular Adhesion Molecule-1 (VCAM-1) expression. The aim of this study is to determine the effects of downregulating Extracellular signal-Regulated Kinase-2 (ERK2) and Akt on insulin and TNFa-stimulated VCAM-1 expression.

Methods

Here we begin to define the relationships between ERK2 and Akt regulation of insulin and TNFα-stimulated VCAM-1 expression in Rat Arterial Endothelial Cells (RAEC) by transfecting RAEC with ERK2 and Akt RNA interference (RNAi) and then treating these cells with insulin (10 nM) or TNFα (10 ng/mL) alone or in combination.

Results

Western blot analyses, flow cytometry and confocal microscopy were used to determine changes in VCAM-1 expression within the above-stated parameters. Cells transfected with ERK2 or Akt RNAi plasmids increased insulin and TNFα-stimulated VCAM-1 total protein expression significantly (P < 0.05) greater than that seen in mock transfected cells and expressed cell surface VCAM-1 greater than that seen in mock transfected cells as indicated by flow cytometry and confocal microscopy. Nevertheless, the decrease of both kinases did not increase insulin or TNFα-stimulated VCAM-1 expression above that seen when one or the other RNAi was present.

Conclusions

Taken together, our results demonstrate that ERK2 and Akt may be negative regulators of insulin and TNF-α stimulated VCAM-1 and that their loss or down regulation might upregulate VCAM-1 expression and contribute to vascular disease.

Atherogenic Cytokines Regulate VEGF-A-Induced Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells into Endothelial Cells

Coronary artery stenting or angioplasty procedures frequently result in long-term endothelial dysfunction or loss and complications including arterial thrombosis and myocardial infarction. Stem cell-based therapies have been proposed to support endothelial regeneration. Mesenchymal stem cells (MSCs) differentiate into endothelial cells (ECs) in the presence of VEGF-A in vitro. Application of VEGF-A and MSC-derived ECs at the interventional site is a complex clinical challenge. In this study, we examined the effect of atherogenic cytokines (IL-6, TNFα, and Ang II) on EC differentiation and function. MSCs (CD44(+), CD73(+), CD90(+), CD14(-), and CD45(-)) were isolated from the bone marrow of Yucatan microswine. Naïve MSCs cultured in differentiation media containing VEGF-A (50 ng/mL) demonstrated increased expression of EC-specific markers (vWF, PECAM-1, and VE-cadherin), VEGFR-2 and Sox18, and enhanced endothelial tube formation. IL-6 or TNFα caused a dose-dependent attenuation of EC marker expression in VEGF-A-stimulated MSCs. In contrast, Ang II enhanced EC marker expression in VEGF-A-stimulated MSCs. Addition of Ang II to VEGF-A and IL-6 or TNFα was sufficient to rescue the EC phenotype. Thus, Ang II promotes but IL-6 and TNFα inhibit VEGF-A-induced differentiation of MSCs into ECs. These findings have important clinical implications for therapies intended to increase cardiac vascularity and reendothelialize coronary arteries following intervention.

Cytosolic Hsp60 orchestrates the survival and inflammatory responses of vascular smooth muscle cells in injured aortic vessels

AIMS

Pro-inflammatory response of vascular smooth muscle cells (VSMCs) is triggered by endothelial damage and a causative step for thrombosis and neointimal thickening in the injured arterial vessels. Therefore, we investigate a role of cytosolic Hsp60 as a novel pro-inflammatory mediator in VSMCs.

METHODS AND RESULTS

Hsp60 was detected in the cytosol of VSMCs. The selective depletion of cytosolic Hsp60 in VSMCs reduced the IκB kinase activation, repressed the induction of nuclear factor (NF)-κB-dependent survival genes (MnSOD and Bfl-1/A1), and enhanced apoptotic death in response to TNF-α. Moreover, a quantitative RNA sequencing revealed that the expression of 75 genes among the 774 TNF-α-inducible genes was significantly reduced by the depletion of cytosolic Hsp60. In particular, the expression of pro-inflammatory cytokines/chemokines, such as CCL2, CCL20, and IL-6, was regulated by the cytosolic Hsp60 in VSMCs. Finally, the depletion of cytosolic Hsp60 markedly inhibited the neointimal thickening in the balloon-injured arterial vessels by inducing apoptotic cell death and inhibiting chemokine production.

CONCLUSIONS

This study provides the first evidence that cytosolic Hsp60 could be a therapeutic target for preventing VSMC hyperplasia and inflammatory response in the injured vessels.

Reduction of endoplasmic reticulum stress inhibits neointima formation after vascular injury

Endoplasmic reticulum (ER) stress and inappropriate adaptation through the unfolded protein response (UPR) are predominant features of pathological processes. However, little is known about the link between ER stress and endovascular injury. We investigated the involvement of ER stress in neointima hyperplasia after vascular injury. The femoral arteries of 7-8-week-old male mice were subjected to wire-induced vascular injury. After 4 weeks, immunohistological analysis showed that ER stress markers were upregulated in the hyperplastic neointima. Neointima formation was increased by 54.8% in X-box binding protein-1 (XBP1) heterozygous mice, a model of compromised UPR. Knockdown of Xbp1 in human coronary artery smooth muscle cells (CASMC) in vitro promoted cell proliferation and migration. Furthermore, treatment with ER stress reducers, 4-phenylbutyrate (4-PBA) and tauroursodeoxycholic acid (TUDCA), decreased the intima-to-media ratio after wire injury by 50.0% and 72.8%, respectively. Chronic stimulation of CASMC with PDGF-BB activated the UPR, and treatment with 4-PBA and TUDCA significantly suppressed the PDGF-BB-induced ER stress markers in CASMC and the proliferation and migration of CASMC. In conclusion, increased ER stress contributes to neointima formation after vascular injury, while UPR signaling downstream of XBP1 plays a suppressive role. Suppression of ER stress would be a novel strategy against post-angioplasty vascular restenosis.

Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) and nuclear factor-κB (NF-κB): a feed-forward loop for systemic and vascular inflammation

The interaction between vascular cells and macrophages is critical during vascular remodeling. Here we report that the scaffolding protein, ezrin-binding phosphoprotein 50 (EBP50), is a central regulator of macrophage and vascular smooth muscle cells (VSMC) function. EBP50 is up-regulated in intimal VSMC following endoluminal injury and promotes neointima formation. However, the mechanisms underlying these effects are not fully understood. Because of the fundamental role that inflammation plays in vascular diseases, we hypothesized that EBP50 mediates macrophage activation and the response of vessels to inflammation. Indeed, EBP50 expression increased in primary macrophages and VSMC, and in the aorta of mice, upon treatment with LPS or TNFα. This increase was nuclear factor-κB (NF-κB)-dependent. Conversely, activation of NF-κB was impaired in EBP50-null VSMC and macrophages. We found that inflammatory stimuli promote the formation of an EBP50-PKCζ complex at the cell membrane that induces NF-κB signaling. Macrophage activation and vascular inflammation after acute LPS treatment were reduced in EBP50-null cells and mice as compared with WT. Furthermore, macrophage recruitment to vascular lesions was significantly reduced in EBP50 knock-out mice. Thus, EBP50 and NF-κB participate in a feed-forward loop leading to increased macrophage activation and enhanced response of vascular cells to inflammation.

Comprehensive gene expression profiling reveals synergistic functional networks in cerebral vessels after hypertension or hypercholesterolemia

Atherosclerotic stenosis of cerebral arteries or intracranial large artery disease (ICLAD) is a major cause of stroke especially in Asians, Hispanics and Africans, but relatively little is known about gene expression changes in vessels at risk. This study compares comprehensive gene expression profiles in the middle cerebral artery (MCA) of New Zealand White rabbits exposed to two stroke risk factors i.e. hypertension and/or hypercholesterolemia, by the 2-Kidney-1-Clip method, or dietary supplementation with cholesterol. Microarray and Ingenuity Pathway Analyses of the MCA of the hypertensive rabbits showed up-regulated genes in networks containing the node molecules: UBC (ubiquitin), P38 MAPK, ERK, NFkB, SERPINB2, MMP1 and APP (amyloid precursor protein); and down-regulated genes related to MAPK, ERK 1/2, Akt, 26 s proteasome, histone H3 and UBC. The MCA of hypercholesterolemic rabbits showed differentially expressed genes that are surprisingly, linked to almost the same node molecules as the hypertensive rabbits, despite a relatively low percentage of ‘common genes’ (21 and 7%) between the two conditions. Up-regulated common genes were related to: UBC, SERPINB2, TNF, HNF4A (hepatocyte nuclear factor 4A) and APP, and down-regulated genes, related to UBC. Increased HNF4A message and protein were verified in the aorta. Together, these findings reveal similar nodal molecules and gene pathways in cerebral vessels affected by hypertension or hypercholesterolemia, which could be a basis for synergistic action of risk factors in the pathogenesis of ICLAD.

Inhibition of NF-κB prevents high glucose-induced proliferation and plasminogen activator inhibitor-1 expression in vascular smooth muscle cells

Recent epidemiologic studies clearly showed that early intensive glucose control has a legacy effect for preventing diabetic macrovascular complications. However, the cellular and molecular processes by which high glucose leads to macrovascular complications are poorly understood. Vascular smooth muscle cell (VSMC) dysfunction due to high glucose is a characteristic of diabetic vascular complications. Activation of nuclear factor-κB (NF-κB) may play a key role in the regulation of inflammation and proliferation of VSMCs. We examined whether VSMC proliferation and plasminogen activator inhibitor-1 (PAI-1) expression induced by high glucose were mediated by NF-κB activation. Also, we determined whether selective inhibition of NF-κB would inhibit proliferation and PAI-1 expression in VSMCs. VSMCs of the aorta of male SD rats were treated with various concentrations of glucose (5.6, 11.1, 16.7, and 22.2 mM) with or without an inhibitor of NF-κB or expression of a recombinant adenovirus vector encoding an IκB-α mutant (Ad-IκBαM). VSMC proliferation was examined using an MTT assay. PAI-1 expression was assayed by real-time PCR and PAI-1 protein in the media was measured by ELISA. NF-κB activation was determined by immunohistochemical staining, NF-κB reporter assay, and immunoblotting. We found that glucose stimulated VSMC proliferation and PAI-1 expression in a dose-dependent manner up to 22.2 mM. High glucose (22.2 mM) alone induced an increase in NF-κB activity. Treatment with inhibitors of NF-κB such as MG132, PDTC or expression of Ad-IκB-αM in VSMCs prevented VSMC proliferation and PAI-1 expression induced by high glucose. In conclusion, inhibition of NF-κB activity prevented high glucose-induced VSMC proliferation and PAI-1 expression.

IκBNS regulates interleukin-6 production and inhibits neointimal formation after vascular injury in mice

AIMS

IκBNS regulates a subset of Toll-like receptor (TLR)-dependent genes including interleukin-6 (IL-6) by inhibiting nuclear factor-κB (NF-κB). IL-6 is an inflammatory biomarker for cardiovascular diseases. The aim of this study was to determine whether IκBNS changes arterial inflammation and intimal hyperplasia after vascular injury.

METHODS AND RESULTS

We investigated neointimal formation in IκBNS-deficient (IκBNS(-/-); C57BL/6 background) and wild-type (IκBNS(+/+)) mice 2 weeks after cuff injury. The mean intimal area and the intima/media ratio of IκBNS(-/-) mice increased 89% (8066 ± 1141 vs. 4267 ± 1095 μm(2); P = 0.027) and 100% (0.72 ± 0.13 vs. 0.36 ± 0.09; P = 0.032) compared with IκBNS(+/+) mice. We observed significant up-regulation of TLR4 in injured arteries of IκBNS(-/-) mice. NF-κB activity in the intima of IκBNS(-/-) mice was 5.1-fold higher (P = 0.008) compared with IκBNS(+/+) mice at 7 days post-injury. IL-6 mRNA levels in injured arteries of IκBNS(-/-) mice were 1.8-fold higher (P = 0.002) compared with those of IκBNS(+/+) mice at 3 days post-injury. Vascular smooth muscle cells from IκBNS(-/-) mice showed a significant increase in cell migration compared with those from IκBNS(+/+) mice after IL-6 stimulation in the scratch-wound healing assay. Furthermore, anti-mouse IL-6 receptor antibody (MR16-1) significantly reduced intimal hyperplasia compared with control IgG injection in IκBNS(-/-) mice. These findings suggest that IL-6 participates in the development of neointimal hyperplasia after vascular injury in IκBNS(-/-) mice.

CONCLUSION

IκBNS down-regulates TLR4 expression, NF-κB activity, and IL-6 production after vascular injury. IκBNS might suppress intimal hyperplasia caused by vascular inflammation such as atherosclerosis, and restenosis after angioplasty.

O-GlcNAc modification of NFκB p65 inhibits TNF-α-induced inflammatory mediator expression in rat aortic smooth muscle cells

Background

We have shown that glucosamine (GlcN) or O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc) treatment augments O-linked-N-acetylglucosamine (O-GlcNAc) protein modification and attenuates inflammatory mediator expression, leukocyte infiltration and neointima formation in balloon injured rat carotid arteries and have identified the arterial smooth muscle cell (SMC) as the target cell in the injury response. NFκB signaling has been shown to mediate the expression of inflammatory genes and neointima formation in injured arteries. Phosphorylation of the p65 subunit of NFκB is required for the transcriptional activation of NFκB. This study tested the hypothesis that GlcN or PUGNAc treatment protects vascular SMCs against tumor necrosis factor (TNF)-α induced inflammatory stress by enhancing O-GlcNAcylation and inhibiting TNF-α induced phosphorylation of NFκB p65, thus inhibiting NFκB signaling.

Methodology/Principal Findings

Quiescent rat aortic SMCs were pretreated with GlcN (5 mM), PUGNAc (10⁻⁴ M) or vehicle and then stimulated with TNF-α (10 ng/ml). Both treatments inhibited TNF-α-induced expression of chemokines [cytokine-induced neutrophil chemoattractant (CINC)-2β and monocyte chemotactic protein (MCP)-1] and adhesion molecules [vascular cell adhesion molecule (VCAM)-1 and P-Selectin]. Both treatments inhibited TNF-α induced NFκB p65 activation and promoter activity, increased NFκB p65 O-GlcNAcylation and inhibited NFκB p65 phosphorylation at Serine 536, thus promoting IκBα binding to NFκB p65.

Conclusions

There is a reciprocal relationship between O-GlcNAcylation and phosphorylation of NFκB p65, such that increased NFκB p65 O-GlcNAc modification inhibits TNF-α-Induced expression of inflammatory mediators through inhibition of NFκB p65 signaling. These findings provide a mechanistic basis for our previous observations that GlcN and PUGNAc treatments inhibit inflammation and remodeling induced by acute endoluminal arterial injury.

CD40 is essential in the upregulation of TRAF proteins and NF-kappaB-dependent proinflammatory gene expression after arterial injury

Despite extensive investigations, restenosis, which is characterized primarily by neointima formation, remains an unsolved clinical problem after vascular interventions. A recent study has shown that CD40 signaling through TNF receptor associated factor 6 (TRAF6) plays a key role in neointima formation after carotid artery injury; however, underlying mechanisms are not clearly elucidated. Because neointima formation may vary significantly depending on the type of injury, we first assessed the effect of CD40 deficiency on neointima formation in 2 injury models, carotid artery ligation and femoral artery denudation injury. Compared with wild-type mice, CD40 deficiency significantly reduced neointima formation and lumen stenosis in two different models. Further, we investigated the mechanism by which CD40 signaling affects neointima formation after arterial injury. In wild-type mice, the expression levels of CD40, several TRAF proteins, including TRAF1, TRAF2, TRAF3, TRAF5, and TRAF6, as well as total NF-kB p65 and phospho-NF-kB p65, in the carotid artery were markedly upregulated within 3-7 days after carotid ligation. Deficiency of CD40 abolished the injury-induced upregulation of TRAFs including TRAF6 and NF-kB-p65 in the injured vessel wall. Further, CD40(-/-) mice showed a significant decrease in the recruitment of neutrophils (at 3, 7d) and macrophages (at 7, 21d) into injured artery; this effect was most likely attributed to inhibition of NF-kB activation and marked downregulation of NF-kB-related gene expression, including cytokines (TNFα, IL-1β, IL-6), chemokines (MCP-1), and adhesion molecules (ICAM-1, VCAM-1). Moreover, neutrophil recruitment in a model of thioglycollate-induced peritonitis is impaired in CD40-deficient mice. In vitro data revealed that CD40 deficiency blocked CD40L-induced NF-kB p65 nuclear translocation in leukocytes. Altogether, our data identified for the first time that CD40 is essential in the upregulation of TRAF6, NF-kB activation, and NF-kB-dependent proinflammatory genes in vivo. Our findings firmly established the role for CD40 in neointima formation in 2 distinct injury models.

Divergent roles of NF-κB and Egr-1 in flow-dependent restenosis after angioplasty and stenting

OBJECTIVE

Restenosis after both angioplasty and stenting is flow dependent. The effects of flow are preventable with the antioxidant pyrrolidine dithiocarbamate (PDTC) after angioplasty but not after stenting. We examined to what extent these observations could be explained by the effect of PDTC on NF-κB and Egr-1, two transcription factors which are both flow- and redox-sensitive.

METHODS

In a flow-modified rabbit carotid model of angioplasty and stenting, we assessed the effects of altered flow, injury and PDTC on expression of Egr-1 and nuclear binding activity of NF-κB. We also examined the effects of local delivery of decoy oligodeoxynucleotides (ODN) specific for NF-κB and Egr-1 on morphology at 28 days in normal and low flow.

RESULTS

The activity of both transcription factors was enhanced by injury (stent>balloon alone) and was further augmented by low flow. PDTC markedly attenuated the activity of NF-κB but not Egr-1. Specific decoy ODN for Egr-1 attenuated intima formation in both stented and balloon injured vessels in both normal and low flow but had no effect on remodelling. In contrast while NF-κB decoy ODN caused a modest but significant reduction in intima formation, there was a striking effect on remodelling in low flow vessels only.

CONCLUSIONS

We conclude that Egr-1 plays a pivotal role in intima formation under all flow conditions and that NF-κB plays a key role in flow-sensitive remodelling after angioplasty and that NF-κB inhibition likely accounts for a significant part of the morphological effects of PDTC after vessel injury.

Gene therapy targeting nuclear factor-kappaB: towards clinical application in inflammatory diseases and cancer

Nuclear factor (NF)-κB is regarded as one of the most important transcription factors and plays an essential role in the transcriptional activation of pro-inflammatory cytokines, cell proliferation and survival. NF-κB can be activated via two distinct NF-κB signal transduction pathways, the so-called canonical and non-canonical pathways, and has been demonstrated to play a key role in a wide range of inflammatory diseases and various types of cancer. Much effort has been put in strategies to inhibit NF-κB activation, for example by the development of pharmacological compounds that selectively inhibit NF-κB activity and therefore would be beneficial for immunotherapy of transplantation, autoimmune and allergic diseases, as well as an adjuvant approach in patients treated with chemotherapy for cancer. Gene therapy targeting NF-κB is a promising new strategy with the potential of long-term effects and has been explored in a wide variety of diseases, ranging from cancer to transplantation medicine and autoimmune diseases. In this review we discuss recent progress made in the development of NF-κB targeted gene therapy and the evolution towards clinical application.

Urokinase mediates endothelial cell survival via induction of the X-linked inhibitor of apoptosis protein

Urokinase-type plasminogen activator (uPA) additionally elicits a whole array of pro-angiogenic responses, such as differentiation, proliferation, and migration. In this study, we demonstrate that in endothelial cells uPA also protects against apoptosis by transcriptional up-regulation and partially by mRNA stabilization of inhibitor of apoptosis proteins, most prominently the X-linked inhibitor of apoptosis protein (XIAP). The antiapoptotic activity of uPA was dependent on its protease activity, the presence of uPA receptor (uPAR) and low-density lipoprotein receptor-related protein (LRP), but independent of the phosphatidylinositol 3 (PI3) kinase pathway, whereas vascular endothelial growth factor (VEGF)–induced antiapoptosis was PI3 kinase dependent. uPA-induced cell survival involved phosphorylation of p21-activated kinase 1 (Pak1) and the IκB kinase α that leads to nuclear factor κB (NF-κB) p52 activation. Indeed, blocking NF-κB activation by using specific NF-κB inhibitors abolished uPA-induced cell survival as it blocked uPA-induced XIAP up-regulation. Furthermore, down-regulating XIAP expression by small interfering RNA (siRNA) significantly reduced uPA-dependent endothelial cell survival. This mechanism is also important for VEGF-induced antiapoptosis because VEGF-dependent up-regulation of XIAP was found defective in uPA−/− endothelial cells. This led us to conclude that uPA is part of a novel NF-κB–dependent cell survival pathway.

Molecular mechanisms of collagen isotype-specific modulation of smooth muscle cell phenotype

OBJECTIVE

Smooth muscle cell (SMC) phenotypic modulation, an important component of atherosclerosis progression, is critically regulated by the matrix, with normal components of the healthy SMC matrix limiting modulation and atherosclerosis-associated transitional matrix proteins promoting phenotypic modulation. We sought to determine how collagen IV (which comprises the healthy artery wall) and monomeric collagen I (which comprises atherosclerotic lesions) differentially affect SMC phenotype.

METHODS AND RESULTS

Plating SMCs on collagen IV resulted in elevated expression of SMC contractility proteins compared to collagen I. Concurrent with enhanced contractile gene expression, collagen IV stimulates binding of SRF to CArG boxes in the promoters of smooth muscle actin and smooth muscle myosin heavy chain. Coll IV also stimulated the expression of myocardin, a critical SRF coactivator required to drive expression of SMC specific genes. In contrast to collagen IV, collagen I stimulated enhanced expression of the inflammatory protein vascular cell adhesion molecule (VCAM)-1. NF-kappaB and NFAT-binding sites in the VCAM-1 promoter are critical for collagen I-mediated expression of VCAM-1 promoter activity. However, only inhibitors of NFAT, not NF-kappaB, were able to reduce collagen I-associated VCAM expression, and collagen I but not collagen IV stimulated NFAT transcriptional activity.

CONCLUSIONS

These results show for the first time that collagen IV and collagen I differentially affect smooth muscle phenotypic modulation through multiple pathways.

Increased protein O-GlcNAc modification inhibits inflammatory and neointimal responses to acute endoluminal arterial injury

Inflammation plays a major role in vascular disease. We have shown that leukocyte infiltration and inflammatory mediator expression contribute to vascular remodeling after endoluminal injury. This study tested whether increasing protein O-linked-N-acetylglucosamine (O-GlcNAc) levels with glucosamine (GlcN) and O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino-N-phenylcarbamate (PUGNAc) inhibits acute inflammatory and neointimal responses to endoluminal arterial injury. Ovariectomized rats were treated with a single injection of GlcN (0.3 mg/g ip), PUGNAc (7 nmol/g ip) or vehicle (V) 2 h before balloon injury of the right carotid artery. O-GlcNAc-modified protein levels decreased markedly in injured arteries of V-treated rats at 30 min, 2 h, and 24 h after injury but returned to control (contralateral uninjured) levels after 14 days. Both GlcN and PUGNAc increased O-GlcNAc-modified protein levels in injured arteries compared with V controls at 30 min postinjury; the GlcN-mediated increase persisted at 24 h but was not evident at 14 days. Proinflammatory mediator expression increased markedly after injury and was reduced significantly (30-50%) by GlcN and PUGNAc. GlcN and PUGNAc also inhibited infiltration of neutrophils and monocytes in injured arteries. Chronic (14 days) treatment with GlcN reduced neointima formation in injured arteries by 50% compared with V controls. Acute GlcN and PUGNAc treatment increases O-GlcNAc-modified protein levels and inhibits acute inflammatory responses in balloon-injured rat carotid arteries; 14 day GlcN treatment inhibits neointima formation in these vessels. Augmenting O-GlcNAc modification of proteins in the vasculature may represent a novel anti-inflammatory and vasoprotective mechanism.

[Development of cell-selective targeting systems of NFkappaB decoy for inflammation therapy]

NFkappaB regulate several inflammatory related molecules and evoke immune and inflammatory response by several stimuli, therefore inhibition of NFkappaB activation would be a novel therapeutic strategy. To date, there are many conventional drugs including nonsteroldal or steroldal anti-inflammatory drugs or immune suppressors etc. were known to inhibit NFkappaB activation, however, several side effects were also reported. Recently, double stranded oligonucleotide including NFkappaB binding sequence, called NFkappaB decoy, was developed to prevent NFkappaB activation, which is powerful tool in a new class of anti-gene strategy for molecular therapy with low side effect. However, NFkappaB decoy is easily degraded by nuclease and rapidly excreted to urine, therefore it is necessary to develop carrier for NFkappaB decoy therapy. Here, we shall review delivery system for NFkappaB decoy and introduce our cell-selective delivery system for NFkappaB decoy using sugar decorated cationic liposomes.

Increased expression of nuclear NF-kappaB after coronary artery balloon injury can be inhibited by intracoronary beta-irradiation

PURPOSE

Molecular mechanisms by which balloon angioplasty injury-induced neointimal hyperplasia can be reduced by intravascular brachytherapy are unclear. We investigated the role of nuclear factor-kappaB (NF-kappaB) in neointimal hyperplasia following intracoronary irradiation.

MATERIALS AND METHODS

Fifty-four coronary arteries from 30 pigs were divided into 6 groups: sham control, balloon angioplasty injury alone, beta-irradiation at doses of 14 or 20 Gy, and 14 or 20 Gy beta-irradiation immediately followed by balloon injury. Coronary arteries were injured by overstretch balloon angioplasty and then the arteries were irradiated using a Rhenium-188 ((188)Re) beta-emitting solution-filled balloon. Pigs were scarified one day or one week after coronary interventions for molecular detection and six weeks after the procedures for histological examination.

RESULTS

Six weeks after coronary interventions, the histological results show that balloon angioplasty injury had induced intimal hyperplasia in coronary artery but the response was significantly reduced by 28% and 60% when the injury was immediately treated by 14 and 20 Gy (188)Re beta-irradiation, respectively. The expression of arterial NF-kappaB p65, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) were detected at one day and one week after the procedures. The treatment of balloon injury could significantly induce the NF-kappaB p65 expression in both gene and protein levels, and such induction could be significantly reduced by (188)Re beta-irradiation at dose of 20 Gy. However, the similar result on the regulation of gene expression affected by the beta-irradiation could not be observed in ICAM-1 and VCAM-1.

CONCLUSION

The inhibitory effect of intracoronary brachytherapy on neointimal formation following overstretch balloon angioplasty could involve inhibition of NF-kappaB p65.

Enhanced sterol response element-binding protein in postintervention restenotic blood vessels plays an important role in vascular smooth muscle proliferation

Postintervention restenosis (PIRS) after balloon angioplasty or stent implantation is a limitation for these interventional procedures even with the advent of new drug-eluting stents. Sterol regulatory element-binding proteins (SREBP) are transcription factors governing cellular lipid biosynthesis and thus critical in the regulation of the lipid-rich cell membranes. PIRS following injury results partially from newly proliferating cells expressing vascular smooth muscle cell (VSMC) markers. Platelet-derived growth factor (PDGF), lysophosphatidic acid (LPA) and alpha(1)-adrenergic receptor stimulation are well recognized diverse mitogens for VSMC activation in PIRS. We examined whether PDGF, LPA and alpha(1)-adrenergic receptor stimulation with phenylephrine (PE) regulate SREBP expression and subsequently, VSMC proliferation. Our results show that PDGF, LPA and PE upregulate SREBP-1 in a time- and dose-dependent manner. PDGF, LPA and PE-mediated proliferation is dependent on SREBP since inhibition of SREBP expression using targeted knockdown of the SREBP precursor SREBP activating protein (SCAP) by siRNA led to an attenuation of SREBP expression and decreased PDGF, LPA and PE induced proliferation. In two different in vivo PIRS models we found that SREBP-1 was enhanced in the injured blood vessel wall, especially within the neointima and co-localized with alpha-smooth muscle actin positive cells. Thus, SREBP is enhanced in the vessel wall following PIRS and is important in the regulation of pro-hyperplasia molecular signaling. SREBP inhibition may be a powerful tool to limit PIRS.

Acetylbritannilactone Inhibits Neointimal Hyperplasia after Balloon Injury of Rat Artery by Suppressing Nuclear Factor-{kappa}B Activation

Based on our previous observations that 1-O-acetylbritannilactone (R)-4((3aS,4S,7aR)-4-hydroxy-6-methyl-3-methylene-2-oxo-2,3,3a,4,7,7a-hexahydrobenzofuran-5-yl)pentyl acetate (ABL) suppresses prostaglandin E(2) and nitric oxide synthesis in macrophages, the present study was designed to explore the effect of ABL on neointimal hyperplasia after balloon injury and its mechanism of action. In male Sprague-Dawley rats, 26 mg/kg ABL or polyglycol (control) was administered daily from 3 days before injury to 2 weeks after conventional balloon injury. ABL administration led to a significant reduction in neointimal formation (neointima to media ratio, 1.94 +/- 0.43 versus 0.84 +/- 0.29, P < 0.01) and proliferative activity of vascular smooth muscle cells after balloon injury in rats. Western blot analysis revealed that this is correlated to the inhibition of nuclear factor (NF)-kappaB activation and to the reduced expression of cyclooxygenase-2. Investigation of potential signaling pathways demonstrated that ABL inhibited NF-kappaB activation via the blockade of the inhibitor of NF-kappaB kinase-beta activation and the suppression of the degradation of the inhibitors of NF-kappaB-alpha. These findings suggest that ABL is a potential inhibitor of neointimal formation because it blocks injury-induced NF-kappaB activation and may have beneficial effects in reducing the risk of restenosis after angioplasty.

A selective NFkappaB inhibitor, DHMEQ, reduced atherosclerosis in ApoE-deficient mice

BACKGROUND AND PURPOSE

Atherosclerosis is a chronic inflammatory process, and anti-inflammatory agents potentially inhibit the development of atherosclerosis. We tested whether a novel NFkappaB inhibitor reduces atherosclerosis.

METHODS

Dehydroxymethylepoxyquinomicin (10 mg/kg) or vehicle (chloromethyl cellulose) was injected intraperitoneally into apoE-deficient mice three times a week for 16 weeks. The entire aorta was excised and atherosclerotic area was determined at 4 and 16 weeks. Serum levels of cholesterol, triglyceride, TNF-alpha and adiponectin were also measured.

RESULTS

The atherosclerotic area was significantly smaller in mice treated with dehydroxymethyl-epoxyquinomicin both at 4 and 16 weeks. There was no significant difference in body weight or serum levels of cholesterol, triglyceride, and adiponectin.

CONCLUSIONS

A new NFkappaB inhibitor, dehydroxymethylepoxyquinomicin, reduced atherosclerosis without affecting plasma lipid levels in apoE-deficient mice.

Restenosis after percutaneous angioplasty: the role of vascular inflammation

Restenosis after endovascular treatment of atherosclerotic lesions in the peripheral, cerebrovascular, and coronary circulation is the major drawback of this minimally invasive technique. Although certain advances have been made during recent years to improve patency rates after percutaneous angioplasty, restenosis remains a challenging clinical problem. Understanding factors that contribute to the pathophysiology of late lumen loss is an effective strategy to improving patients' postangioplasty outcome. Vascular inflammation after balloon angioplasty or stent implantation has been identified as a cornerstone of the restenotic process, and several markers of inflammation have been referred to as potential predictors of outcome. This article reviews recent findings on the issue of inflammation and restenosis after percutaneous angioplasty with special attention given to the role of inflammatory parameters as markers for the restenosis risk in the peripheral vessel area.

Gene therapy of fibroproliferative vasculopathies: current ideas in molecular mechanisms and biomedical technology

Intimal hyperplasia occurs primarily as a part of the pathogenesis of coronary artery disease or secondary to therapeutic intervention in relieving vascular occlusion. Intimal hyperplasia involving vascular smooth muscle cells is found in atherosclerosis, post-balloon angioplasty restenosis, in-stent restenosis and vein graft disease, predominantly involving the use of saphenous vein conduits in coronary artery bypass grafting procedures. One potentially exciting area is that of gene therapy. Gene and protein expression patterns at the site of vasculoproliferative lesions have been widely studied and several target areas have been identified on the basis of whether the gene has an antiproliferative, proapoptotic, matrix degrading or endothelial protective action. Blood vessels are easily accessible for the delivery of the gene product, and experimental studies using animal models have used catheter-delivered gene products at the site of vascular injury. Currently, the application of antisense technology and adenoviral vector-mediated delivery has shown significant promise, albeit in in vitro or animal model settings. In this review, we discuss the current knowledge in the application of gene therapy in fibroproliferative vasculopathies. We examine some of the cellular mechanisms and intermediaries which could be potential candidates for gene targeting. We also present some of the advances in biomedical technology that might provide useful vehicles for pinpoint delivery of the gene product. Could the future of restenosis treatment be in gene therapy or is it misplaced enthusiasm?

Propionyl-L-carnitine Reduces Proliferation and Potentiates Bax-related Apoptosis of Aortic Intimal Smooth Muscle Cells by Modulating Nuclear Factor-κB Activity

Propionyl-l-carnitine (PLC) has been introduced among the therapeutic approaches of peripheral arterial disease, and more recently, an increase of intimal cell apoptosis has been demonstrated to contribute to its effectiveness in rabbit carotid postinjury myointimal hyperplasia prevention. How PLC mediates these effects on vascular smooth muscle cells (SMCs) remains poorly understood. We investigated the role of NF-kappaB in PLC-induced arterial remodeling. In vivo, daily PLC treatment 15 days after injury resulted in a reduction of relative rat aortic intimal volume, an increase of apoptosis, Bax up-regulation without changing the Bcl-2 level, and a reduction of NF-kappaB, vascular cell adhesion molecule-1, monocyte chemotactic protein-1, and survivin in myointimal thickening compared with controls. In the presence of 10% serum, a reduced G(1) --> S phase progression preceded PLC-induced intimal cell apoptosis; in 0.1% serum cultures, in a dose-dependent manner, PLC rapidly induced intimal cell apoptosis and reduced p65, p50, IAP-1, and IAP-2 expression. Inhibiting NF-kappaB activation through SN50 increased apoptotic rate and Bax expression in intimal but not in medial SMCs, and successive PLC treatment failed to induce a further increase in apoptotic rate. Bax antisense oligodeoxynucleotide reduced PLC-induced intimal cell apoptosis and cytochrome c release. The PLC-induced attenuation of NF-kappaB activity in intimal cells was also due to the increase of IkappaB-alpha bioavailability, as the result of a parallel induction of IkappaB-alpha synthesis and reduction of phosphorylation and degradation. Collectively, these findings document that NF-kappaB activity inhibition contributes to PLC-induced proliferative arrest and Bax-related apoptosis of intimal SMCs.

Gene deletion of NF-kappaB p105 enhances neointima formation in a mouse model of carotid artery injury

The role of nuclear factor kappa-B (NF-kappaB) p105 for vascular inflammatory gene expression and neointima formation after arterial injury was studied. Mice carotid arteries were injured by ligation. Vascular NF-kappaB activation was monitored using a NF-kappaB luciferase reporter mouse. Mice with gene deletion of the NF-kappaB p105 subunit (p50 precursor) and the corresponding wild types were assessed for vascular gene expression and neointimal hyperplasia. NF-kappaB was activated in the injured vessel wall in wild type mice, and this was accompanied by increased expression of the proinflammatory genes tumor necrosis factor alpha, interleukin 1 beta, and inducible nitric oxide synthase. In contrast, NF-kappaB p105 knockout mice had reduced expression of the inflammatory genes and enhanced neointima formation four weeks after ligation. Basic fibroblast growth factor (bFGF) gene expression increased after arterial ligation. A higher percentage of bFGF positive cells were found in lesions from NF-kappaB p105 knock out mice. These data indicate that the p105 subunit of NF-kappaB plays an essential role in vascular healing, and defects in NF-kappaB p105 promote neointima hyperplasia.

NF-kappaB activity and iNOS expression in monocytes from internal jugular blood of migraine without aura patients during attacks

This study investigated nuclear factor-kappa B (NF-kappaB) activity by electrophoresis mobility gel shift assay and IkappaBalpha expression by Western blot analysis in monocytes obtained from serial samples of internal jugular venous blood taken from seven migraine patients without aura during attacks. Inducible nitric oxide synthase (iNOS) expression was also assessed by reverse transcription-polymerase chain reaction. An increase in NF-kappaB activity peaked 2 h after attack onset. This was accompanied by a transient reduction in IkappaBalpha expression. Up-regulation of iNOS was evident at 4 h, maintained at 6 h and reduced at the end of the attack. These findings substantiate the hypothesis of transitory delayed inflammation, as suggested by the animal model, and suggest the possibility of using therapeutic approaches to target NF-kappaB transcription in the treatment of migraine.

Countervailing effects of rapamycin (sirolimus) on nuclear factor-κB activities in neointimal and medial smooth muscle cells

OBJECTIVE

Local application of rapamycin (sirolimus) by drug-eluting stents prevents lumen obliteration after angioplasty by inhibition of neointimal hyperplasia. The effects of rapamycin on neointimal smooth muscle cells (niSMC) which are responsible for the occurrence of restenosis have not been investigated so far.

METHODS AND RESULTS

Rat niSMC and medial SMC (mSMC) were obtained from balloon catheter-injured arteries. The niSMC exhibited higher basal NF-kappaB activity and TNF-alpha mRNA levels. Nuclear protein binding to NF-kappaB-DNA was attenuated in niSMC by incubation with rapamycin (0.1 and 1 microg/ml) for 24 and 48 h. In contrast in mSMC, 0.1 microg/ml rapamycin had no effect and at 1 microg/ml even increased nuclear protein binding to NF-kappaB-DNA. After 12 h incubation, rapamycin (0.001-10 microg/ml) induced IkappaB-alpha protein in niSMC, whereas in mSMC it stimulated IkappaB-alpha at much lower levels. Prolonged rapamycin treatment (1 microg/ml for 72 h) had no effect on TNF-alpha mRNA level and NF-kappaB activity in niSMC, whereas it led to their increase in mSMC. Vascular endothelial growth factor (VEGF) secretion was higher in mSMC than in niSMC; rapamycin decreased VEGF levels in both cell types. Ultrastructural analysis suggested that rapamycin caused early signs of degeneration in niSMC, but enhanced protein synthesis in mSMC.

CONCLUSIONS

This study shows that rapamycin influences the inflammatory phenotypes of SMC in opposite directions: it reduces the high basal NF-kappaB activity in niSMC and enhances NF-kappaB activity and TNF-alpha expression in mSMC. In addition, rapamycin inhibits VEGF production regardless of the phenotype of SMC. These findings shed light on molecular mechanisms and structural changes underlying therapeutic applications of rapamycin in prevention of restenosis, inhibition of chronic transplant arteriosclerosis and reduction of secondary malignoma formation due to immunosuppression.

Inflammatory responses involving tumor necrosis factor receptor-associated factor 6 contribute to in-stent lesion formation in a stent implantation model of rabbit carotid artery

OBJECTIVE

Inflammatory responses are considered to represent a unique property after stent implantation, and we previously demonstrated that inflammatory signaling involving tumor necrosis factor receptor-associated factor 6 (TRAF6) contributes to neointimal formation in a balloon injury model of rabbit carotid artery. The purpose of this study was to examine the role of TRAF6 in in-stent lesion formation after stent implantation in the rabbit carotid artery.

METHODS

Rabbit carotid arteries were injured with a 2F Fogarty catheter, and 28 days later, the same arteries were implanted with a 3-mm-diameter Palmaz-Schatz stent. A dominant negative (DN) form of TRAF6 (pME-FLAG-T6deltaRZ5) was then transferred using a plasmid-based electroporation method. Its effects were evaluated compared with the findings in arteries treated with control plasmid (pME-FLAG).

RESULTS

Immunostaining with anti-FLAG tag antibody showed that an expression plasmid vector containing the DN-TRAF6 sequence was successfully transferred to the arterial intima and media. Morphometric analyses revealed that the increase of intimal area in in-stent lesions was significantly inhibited by DN-TRAF6 14 days after stent implantation (DN-TRAF6 group, 3.01 +/- 0.25 x 10(5) microm2 vs control group, 4.25 +/- 0.23 x 10(5) microm2, P < .01), and the cell density was increased compared with that in the control group. In the DN-TRAF6 plasmid-treated vessels, cell replication was prevented in both the intima and media, and fewer leukocytes adhered to the luminal surface. Moreover, DN-TRAF6 suppressed macrophage infiltration, activation of proteases, and proteoglycan accumulation in the in-stent intima.

CONCLUSIONS

These findings suggest that TRAF6 plays an important role in cell replication, inflammatory cell infiltration, protease activity, and extracellular matrix accumulation that contributes to in-stent lesion development.

Anti-atherogenic properties of fibrates may be largely due to their anti-inflammatory effects

Current understanding of the pathophysiology of atherosclerosis has undergone a remarkable evolution. Compelling evidence has evolved at both the basic science and clinical level for the importance of inflammation in the pathogenesis of atherosclerosis and its complications. Recent research has shown that both systemic and local inflammation plays a central role in all phases of the atherosclerotic process. Inflammatory cells dominate early atherosclerotic lesions, inflammatory cytokines accelerate progression of the lesions, and activation of inflammation can elicit acute coronary syndromes. Robust clinical studies have affirmed that fibrates are anti-atherogenic and can improve the cardiovascular risk profile. Fibrates not only modulate the serum concentrations of triglyceride and cholesterol, but also inhibit systemic inflammatory statue and inflammatory response in vascular cells. Fibrates act anti-inflammatory effects in monocyte/macrophage, T lymphocyte, endothelial cells, vascular smooth muscle cells and adipocytes. Since atherosclerosis is now regarded as an inflammatory disease and those inflammatory cells play critical important roles in the initiation and development of atherosclerosis, we hypothesize that anti-atherogenic properties of fibrates may be largely due to their anti-inflammatory effects.

Fructose-1,6-diphosphate suppresses T-lymphocyte proliferation, promotes apoptosis and inhibits interleukins-1, 6, beta-actin mRNAs, and transcription factors expression

The overall objective of this study was to determine the role fructose 1,6-diphosphate (FDP), a naturally occurring glycolytic intermediate, plays in activated T-lymphocytes. The hypothesis is twofold. First, we propose that FDP inhibits T cell proliferation to a greater extent than fructose-1-phosphate (F1P), fructose-6-phosphate (F6P) and mannose-6-phosphate (M6P); second, we argue that FDP suppresses immune activation by inhibiting inflammatory cytokine expression, inhibiting expression of key transcription factors, and by inducing apoptosis in immune cells. Rat spleen cells were incubated with concanavalin A (ConA) and increasing concentrations of FDP. Proliferation was determined by tritiated thymidine uptake. FDP inhibited splenocyte proliferation in a dose-related manner while F1P, F6P, M6P demonstrated inhibition only at high concentrations (5000 microg/ml). RNA was harvested from FDP and ConA-treated cells and IL-1 and IL-6 gene expression was analyzed by RT-PCR. IL-1 and IL-6 mRNA expression was completely inhibited at 500-5000 microg/ml FDP. Apoptosis in FDP-treated lymphocytes was determined by DNA fragmentation and flow cytometry. Propidium iodide (PI) staining demonstrated a 39% rate of apoptosis in splenocytes treated with ConA and 5000 microg/ml FDP. Extensive DNA fragmentation was present at 250-5000 microg/ml FDP, and maximal inhibition occurred at 5 microg/ml. F1P, F6P and M6P showed maximal inhibition only at 5000 microg/ml. Nuclear extracts from FDP-treated splenocytes were analyzed by electrophoretic mobility shift assay. ConA activation of NF-kappaB and AP-1 was dramatically inhibited by FDP. Interestingly, beta-actin showed extensive inhibition with FDP and ConA, thus suggesting new possibilities of its being used as a therapeutic modality in arterial injury where the beta-actin, an important cytoskeleton element, plays a very important role. These data indicate that FDP may be a useful immunosuppressive agent. In conclusion, FDP is not only an immunosuppressant but also an anti-inflammatory agent.

Roxithromycin is an inhibitor of human coronary artery smooth muscle cells proliferation: a potential ability to prevent coronary heart disease

Roxithromycin (RXM), a macrolide antibiotic, is used in clinical trials to address secondary prevention of coronary heart disease. However, the effects of RXM on human coronary artery smooth muscle cells (CASMC) proliferation remain unclear. Human CASMC were stimulated with growth medium containing 5% fetal bovine serum and growth factors. RXM at 1 or 10 microg/ml, which are relevant to the therapeutic plasma levels, significantly suppressed mitogen-induced CASMC proliferation, assessed by WST-1 assay and cell counting. Flow cytometry analysis demonstrated that RXM suppressed mitogen-induced G1 to S progression on cell cycle. Western blot showed that RXM inhibited phosphorylation of retinoblastoma gene products, reduced protein levels of cyclin D1 and A, and restored downregulation of cyclin-dependent kinase (CDK) inhibitor p27kip1. The activities of CDK4 and CDK2 were suppressed by RXM without affecting their protein levels. When transfected with both IkappaB kinase alpha and beta constructs as nuclear factor-kappa B (NF-kappaB) activator, CASMC entered S phase at 24 h, and RXM inhibited it. Electrophoretic mobility shift assay and immunostaining of NF-kappaB p65 demonstrated that RXM inhibited mitogen-induced NF-kappaB activation. These results indicate that RXM is an inhibitor of human CASMC proliferation through modulating cell cycle regulatory proteins and inhibiting NF-kappaB signaling pathway.

Mechanisms of monocyte recruitment in vascular repair after injury

The inflammatory response to acute vessel wall injury has been increasingly recognized to play a decisive role in neointima formation. In particular, the exuberant infiltration with monocytes aggravates neointimal growth and can thereby promote restenosis. The adhesion of circulating monocytes to the site of mechanical injury represents the key event in monocyte recruitment, and this review highlights recent insights into the molecular mechanisms of monocyte adhesion throughout the course of neointimal growth. An acute and a chronic phase of monocyte recruitment after vascular injury can be discerned. The adhesion of platelets to the denuded subendothelial matrix is the hallmark of the acute phase providing an adhesive substrate for monocytes, whereas chronic monocyte recruitment is regulated by the interaction with neointimal smooth muscle cells and recovering endothelial cells. Clearly, the mechanisms of monocyte rolling and adhesion differ considerably between these diverse substrates. This review is particularly focused on the contribution of chemokines and adhesion molecules to monocyte recruitment to injured vessels according to the different stages of neointimal growth, and on closely related functions of the chemokine-like molecule macrophage migration inhibitory factor. Understanding the complex molecular interactions of the injured vessel wall with circulating monocytes may enable therapeutic targeting to prevent the development of restenosis.

Local administration of NF-kappa B decoy oligonucleotides to prevent restenosis after balloon angioplasty: an experimental study in New Zealand white rabbits

PURPOSE

To evaluate the efficacy of NF-kappa B oligonucleotides (ODN) administered by local administration with the channeled balloon catheter to prevent restenosis after balloon angioplasty in restenotic iliac arteries of New Zealand white rabbits.

MATERIALS AND METHODS

In vitro, 8000 rabbit vascular smooth muscle cells (rVSMC) where transfected with a liposomal carrier (TfX50) with 100 ng of decoy and scrambled ODN. Inhibition of proliferation was measured using a MTT assay after 24 hours in comparison to control. In vivo, 22 male New Zealand White rabbits were fed a 1% cholesterol diet and received denudation of both common iliac arteries with a 3 mm balloon catheter to induce an arterial stenosis. Four weeks after stenosis induction, local application of NF-kappa B in two different concentrations (1 mug: n = 14; 10 mug: n = 8) was performed randomly on one common iliac artery. Scrambled oligonucleotides without specific binding capacities were injected into the contralateral side. The channeled balloon catheter allows simultaneous balloon dilation (8 atm) of the stenosis and local application of a drug solution (2 atm). Four weeks after local drug delivery the animals were killed and the vessels were excised and computerized morphometric measurements were performed.

RESULTS

NF-kappa B decoy ODN but not scrambled ODN inhibited proliferation of rVSMC in vitro. Following local ODN application in the animals, no acute vascular complications were seen. NF-kappa B ODN resulted in a statistically non significant reduction of neointimal area compared to the control group. The neointimal area was 0.97 mm(2) using 1 mug NF-kappa B ODN compared to 0.98 mm(2) in the control group. The higher dose resulted in a neointimal area of 0.97 mm(2) compared to 1.07 mm(2) at the control side.

CONCLUSIONS

Local drug delivery of NF-kappa B ODN using the "channeled balloon" catheter could not reduce neointimal hyperplasia in stenostic rabbit iliac arteries. Application modalities have to be improved to enhance the effect of the local application to prevent restenosis after balloon angioplasty.

Inflammatory response after intervention assessed by serial C-reactive protein measurements correlates with restenosis in patients treated with coronary stenting

OBJECTIVES

We hypothesized that a higher degree of inflammatory response to coronary stenting, as measured by the change in C-reactive protein (CRP) levels after intervention in patients with stable or unstable angina, would be related to a higher risk of in-stent restenosis.

METHODS

We studied 1800 consecutive patients with stable or unstable angina treated with coronary stenting. C-reactive protein levels were serially measured before and after the intervention. The difference (Delta) between highest CRP values after intervention and CRP values before intervention was calculated. Patients were grouped into tertiles according to DeltaCRP values. The primary end point was angiographic restenosis (diameter stenosis > or = 50% at 6-month angiography). The secondary end point was clinical restenosis, defined as target vessel revascularization performed in the presence of angiographic restenosis and symptoms or signs of ischemia.

RESULTS

No relationship was found between CRP values at baseline and angiographic restenosis (P = .88). On the other hand, the change between baseline and peak postintervention CRP values strongly correlated with angiographic restenosis (30.5% in the upper tertile with DeltaCRP values >11.8 mg/L, 25.3% in the middle tertile with DeltaCRP values 3.0-11.8 mg/L, and 21.5% in the lower tertile with DeltaCRP values < 3.0 mg/L, P = .002) as well as with clinical restenosis (P = .01). Patients in the upper tertile had the highest risk of restenosis even after adjustment for other covariates.

CONCLUSIONS

The inflammatory response to coronary stenting as assessed by the change in CRP correlates with the development of in-stent restenosis. These findings provide strong support for the role of inflammation in restenosis.

IKKbeta-dependent NF-kappaB pathway controls vascular inflammation and intimal hyperplasia

Nuclear factor-kappaB (NF-kappaB)-mediated vascular inflammation is a prominent characteristic of atherogenesis and restenosis. We noted that angioplastic injury to carotid artery elicited two phases of NF-kappaB activation characterized by an early activation in the arterial media and a late activation coupled with high levels of inhibitor of IkappaB kinase (IKK) activity in intima. These findings prompted us to elucidate the role for the different phases of NF-kappaB activation and IKK in the progress of vascular repair. Our results show that blockade of the early NF-kappaB activation by perivascular administration of pyrrolidine dithiocarbamate transiently attenuates the expression of proinflammatory genes in the injured vessels but does not affect intimal formation. Interruption of IKKbeta by overexpressing a dominant-negative IKKbeta in the injured artery effectively inhibited the late phase of NF-kappaB activation, resulting in down-regulation of inducible nitric oxide synthase, tumor necrosis factor alpha, and monocyte chemoattractant protein-1 expression in conjunction with a 36% reduction in intima size, albeit with a lack of inhibitory effect on the early NF-kappaB activation. Collectively, these findings show that the IKKbeta-mediated late-phase NF-kappaB activation contributes to intimal hyperplasia and the accompanied vascular inflammatory responses.

Thematic review series: The immune system and atherogenesis. Cytokines affecting endothelial and smooth muscle cells in vascular disease

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.

Rationale and study design of the CardioGene Study: genomics of in-stent restenosis

BACKGROUND AND AIMS

in-stent restenosis is a major limitation of stent therapy for atherosclerosis coronary artery disease. The CardioGene Study is an ongoing study of restenosis in bare mental stents (BMS) for the treatment of coronary artery disease. The overall goal is to understand the genetic determinants of the responses to vascular injury that result in the development of restenosis in some patients but not in others. Gene expression profiling at transcriptional and translational levels provides global assessment of gene activity after vascular injury and mechanistic insight. Furthermore, the delineation of genetic biomarkers would be of value in the clinical setting of risk-stratify patients prior to stent therapy. Prospective risk stratification would allow for the rational selection of specialized treatments against the development of in-stent restenosis (ISR), such as drug-eluting stents.

SETTING

Patients are enrolled at two sites in the US with high-volume cardiac catheterization facilities: the William Beaumont Hospital in Royal Oak, MI, USA, and the Mayo Clinic in Rochester, MN, USA.

STUDY DESIGN

Two complementary study designs are used to understand the molecular mechanisms of restenosis and the genetic biomarkers predictive of restenosis. First, 350 patients are enrolled prospectively at the time of stent implantation. Blood is sampled prior to stent placement and afterwards at 2 weeks and 6 months. The clinical outcome of restenosis is determined 6 and 12 months after stent placement. The primary outcome is clinical restenosis at 6 months. The major secondary outcome is clinical restenosis at 12 months. Second, a corollary case-control analysis will be carried out with the enrollment of an additional 250 cases with a history of recurrent restenosis after treatment with BMS. Controls for this analysis are derived from the prospective cohort.

PATIENTS AND METHODS

Consecutive patients presenting to the cardiac catheterization laboratory are screened, informed about the study and enrolled after signing the consent form. Enrollment has been completed for the prospective cohort, and enrollment of the additional group is ongoing. A standardized questionnaire is used to collect clinical data primarily through direct patient interview to assess medical history, medication use, functional status, family history, environmental factors, and social history. Further data are abstracted from the medical charts and catheterization reports. A total of 276 clinical variables are collected per individual at baseline, and 49 variables are collected at each of the 6- and 12-month follow-up visits. A Clinical Events Committee adjudicates clinical outcomes. Blood samples are processed at each clinical enrollment site using standardized operating procedures. From each blood sample, several aliquots are prepared and stored of peripheral blood mononuclear cells, granulocytes, platelets, serum, and plasma. Additionally, a portion of each patient's leukocytes is cryopreserved for future cell-line creation. Samples are frozen and shipped to the National Heart, Lung and Blood Institute (NHLBI). Additional materials generated in the analysis of the samples at the NHLBI are frozen and stored, including isolated genomic DNA, total RNA, reverse transcribed cDNA libraries and labeled RNA hybridization mixtures used in microarray analysis. Per individual in the prospective cohort, high-quality transcript profiles of peripheral blood mononuclear cells at each time of blood sampling are obtained using Affymetrix U133A microarrays (Affymetrix, Santa Clara, CA, USA). Per chip, this yields 495,930 features per individual per time of sampling. This represents expression levels for 22,283 genes per patients oer time of blood sampling, including 14,500 well-characterized human genes. Proteomics of plasma is performed with multidimensional liquid chromatography and tandem mass spectrometry. Protein expression is examined similarly to mRNA expression as a measure of gene expression. Genotyping is performed in two manners. First, those genes showing differential expression at the levels of mRNA and protein are investigated using a candidate gene approach. Specific variants in known gene regulatory regions, such as promoters, are sought initially, as those variants may explain differences in expression level. Second, a genome-wide scan is used to identify genetic loci that are associated with ISR. Those regions identified are further examined for genes that show differential expression in the mRNA microarray profiling or proteomics investigations. These genes are finely investigated for candidate SNPs and other gene variants. Complementary genomic and proteomic approaches are expected to be robust. Integration of data sets is accomplished using a variety of informatics tools, organization of gene expression into functional pathways, and investigation of physical maps of up- and downregulated sets of genes.

CONCLUSIONS

The CardioGene Study is designed to understand ISR. Global gene and protein expression profiling define molecular phenotypes of patients. Well-defined clinical phenotypes will be paired with genomic data to define analyses aimed to achieve several goals. These include determining blood gene and protein expression in patients with ISR, investigating the genetic basis of ISR, developing predictive gene and protein biomarkers, and the identification of new targets for treatment.