Evidence supporting changes in Nogo-B levels as a marker of neointimal expansion but not adaptive arterial remodeling

High shear stress attenuated arterial neointimal hyperplasia accompanied by changes in yes-associated protein/jun N-terminal kinase/vascular cell adhesion protein 1 expression

BACKGROUND AND OBJECTIVES

Abnormal neointimal hyperplasia (NIH) is known as the predominant mechanism in the pathogenesis of arterial restenosis after balloon angioplasty. Low shear stress (SS) is known to augment balloon injury-induced NIH. The aim of this study is to study the effect and mechanisms of an increase of shear stress caused by arteriovenous fistula could alleviate arterial NIH caused by balloon injury.

METHODS AND RESULTS

Eighteen male rabbits were randomly divided into three groups: BI-the rabbits received a balloon injury to right common carotid artery (CCA). BI+AVF-the rabbits received a balloon injury to right CCA and a carotid-jugular AVF. Control-the animals received no surgery. After 21 days, CCA samples were harvested for histological staining, immunohistochemistry, and western blot analysis. The luminal shear stress of the BI+AVF group increased from 13.8 ± 1.0 dyn/cm² before surgery to 30.9 ± 1.7 dyn/cm² right after surgery (p < 0.01). This value was higher than that of the BI or Control groups at any timepoint. The neointimal area and neointima/media area ratio in the BI+AVF group were significantly lower than those in the BI group. In the BI group, the cellular proliferation, the protein levels of yes-associated protein (YAP), connective tissue growth factor (CTGF), phospho-c-Jun N-terminal kinase (pJNK), and vascular cell adhesion protein 1 (VCAM1) increased, whereas the protein levels of SMCs specific genes decreased. In the BI+AVF group, the opposite effect was observed as cellular proliferation and the protein levels of YAP, CTGF, pJNK, and VCAM1 decreased, the protein levels of SMCs specific genes increased.

CONCLUSION

The arteriovenous fistula alleviated the balloon injury-induced arterial NIH. It elevated the luminal shear stress and inhibited SMCs phenotypic modulation to the synthetic state, as well as suppressing the over-activation of YAP, JNK, and VCAM1.

The Regulatory Role of Reticulons in Neurodegeneration: Insights Underpinning Therapeutic Potential for Neurodegenerative Diseases

In the last few decades, cytoplasmic organellar dysfunction, such as that of the endoplasmic reticulum (ER), has created a new area of research interest towards the development of serious health maladies including neurodegenerative diseases. In this context, the extensively dispersed family of ER-localized proteins, i.e. reticulons (RTNs), is gaining interest because of its regulative control over neural regeneration. As most neurodegenerative diseases are pathologically manifested with the accretion of misfolded proteins with subsequent induction of ER stress, the regulatory role of RTNs in neural dysfunction cannot be ignored. With the limited information available in the literature, delineation of the functional connection between rising consequences of neurodegenerative diseases and RTNs need to be elucidated. In this review, we provide a broad overview on the recently revealed regulatory roles of reticulons in the pathophysiology of several health maladies, with special emphasis on neurodegeneration. Additionally, we have also recapitulated the decisive role of RTN4 in neurite regeneration and highlighted how neurodegeneration and proteinopathies are mechanistically linked with each other through specific RTN paralogues. With the recent findings advocating zebrafish Rtn4b (a mammalian Nogo-A homologue) downregulation following central nervous system (CNS) lesion, RTNs provides new insight into the CNS regeneration. However, there are controversies with respect to the role of Rtn4b in zebrafish CNS regeneration. Given these controversies, the connection between the unique regenerative capabilities of zebrafish CNS by distinct compensatory mechanisms and Rtn4b signalling pathway could shed light on the development of new therapeutic strategies against serious neurodegenerative diseases.

Nogo-B is a key mediator of hepatic ischemia and reperfusion injury

Nogo-B is an endoplasmic reticulum-residential protein with distinctive functions in different diseases. However, it remains unclear the role of Nogo-B in liver sterile inflammatory injury. This study aims to elucidate the functions and mechanisms in liver ischemia and reperfusion injury (IRI). The Nogo-B expression and liver function were analyzed in biopsy/serum specimens from 36 patients undergoing ischemia-related hepatectomy and in a mouse model of liver IRI. Human specimens were harvested prior to ischemia and post-reperfusion. The Nogo-B knockout (Nogo-B^KO) and myeloid-specific Nogo-B knockout (Nogo-B^MKO) mice were used to analyze the function and mechanism of Nogo-B in a mouse model of liver IRI. In human specimens, the Nogo-B expression was positively correlated with higher levels of serum transaminase (sALT) and severe histopathological injury at one day post-hepatectomy. Moreover, Nogo-B is mainly expressed on macrophages in normal and ischemic liver tissues from human and mice. Unlike in controls, the Nogo-B^KO or Nogo-B^MKO livers was protected against IRI, with reduced reactive oxygen species (ROS) production and liver inflammation in ischemic livers. In parallel in vitro studies, Nogo-B deficiency reduced M1 macrophage polarization and inhibited proinflammatory cytokines (TNF-α, IL-6, MCP-1 and iNOS) in response to LPS or HMGB-1 stimulation. Mechanistic studies showed that Nogo-B bound to MST1/2, increased MST1/2, LAST1, and YAP phosphorylation, leading to reduced YAP activity. Interestingly, disruption of macrophage YAP abolished Nogo-B deficiency-mediated cytoprotective effects in vitro and in vivo. Thus, YAP is crucial for the regulation of macrophage Nogo-B-triggered liver inflammation. Nogo-B promotes macrophage-related innate inflammation and contributes to IR-induced liver injury by activating the MST-mediated Hippo/YAP pathway, which provides a potential therapeutic target for clinical management in liver IRI.

Knockout of the Nogo-B Gene Attenuates Tumor Growth and Metastasis in Hepatocellular Carcinoma

Human hepatocellular carcinoma (HCC) is a malignant cancer. It is a challenge to develop anti-HCC drugs due to HCC's extreme aggressiveness and with the sensitivity of the liver to show severe adverse effects. More importantly, the precise mechanisms causing HCC pathogenicity are not known. Our previous study disclosed Nogo-B as a reticulon 4 (Rtn4) family member. In the present study, we first identified that Nogo-B played a critical role in HCC progression. We found, via in vitro and in vivo assays, that Nogo-B was expressed aberrantly in primary HCC tumor tissues and immortal HCC cells but was relatively scarce in the normal liver tissues or cells. Nogo-B knockout, via the CRISPR-Cas9 technique, resulted in significant suppression of HCC cell proliferation and tumor growth. Next-generation sequencing analysis showed that Nogo-B knockout have effects on interleukin-6 (IL-6) signaling pathway. Furthermore, we observed that IL-6 induced phosphorylation of STAT3 (pSTAT3) in wild-type HCC cells, but Nogo-B knockout could reduce IL-6-induced increase of pSTAT3, supporting that Nogo-B affects HCC tumor progression possibly via regulating the IL-6/STAT3 signaling pathway. In conclusion, Nogo-B is expressed aberrantly in HCCs and plays an oncogenic role. These findings support that Nogo-B may be a novel anti-HCC therapeutic target.

Nogo-C contributes to HCC tumorigenesis via suppressing cell growth and its interactome analysis with comparative proteomics research

OBJECTS

Neurite outgrowth inhibitor proteins (Nogos) comprise a family of three major members and are characterized by a conserved RHD domain. Among all the members, Nogo-B was identified to be significantly elevated and to play an important role in liver cirrhosis while Nogo-C was the shortest one and received little attention. The aim of this study is to investigate the relevance and mechanism of Nogo-C involved in Hepatocellular carcinoma (HCC).

METHODS

The expression of Nogo-C in paired HCC specimens was measured with quantitative RT-PCR. The function of Nogo-C over expressing in SMMC-7721 and WRL-68 HCC cell lines were estimated through cell proliferation assay and colony formation assay. A proteome-wide identification of Nogo-C-binding proteins was performed using affinity purification combined with a highly sensitive mass spectrometric technique. The protein interactions were confirmed using co-IP and immunofluorescence confocal assays.

RESULTS

Compared with the neighboring pathologically normal tissues, the expression of Nogo-C mRNA was extremely down-regulated in HCC specimens and was significantly related to greater tumor size and worse prognosis. Overexpression of Nogo-C in HCC cell lines resulted in an inhibition of cell growth. A total of 73 proteins were detected and considered in association with Nogo-C, among which B-raf and Nogo-B were validated.

CONCLUSION

We identify Nogo-C as a tumor suppressor gene in HCC and B-raf as a novel interacting protein. These findings provide new directions for the mechanism research of Nogo family.

Nogo-B expression, in arterial intima, is impeded in the early stages of atherosclerosis in humans

Nogo-B (Reticulon 4B) is considered to be a novel vascular marker, which may have a protective role in injury-induced neointima formation and atherosclerosis. Nogo A/B is found to be crucial for monocyte/macrophage recruitment in acute inflammation and it is expressed in CD68 + macrophages. We hypothesize that macrophage infiltration in atherosclerosis is not dependent on Nogo-B expression in arterial wall. We have assessed Nogo-B expression and macrophage accumulation in the iliac arteries of healthy organ donors and organ donors with cardiovascular risk factors. Paraffin sections of 66 iliac arteries, from 44 deceased organ donors (17 women and 27 men), were studied. The healthy and cardiovascular risk (CVR) subgroups were created. With regard to staging of the atherosclerotic process, the thickness of arterial intima was measured in digitalized images of H+E stained tissue sections. Immunohistochemical reactions (Nogo-B and CD68) were carried out in all arteries (66 samples). Western blotting (WB-19 samples) and real-time PCR (27 samples) were performed on selected arteries. Significantly higher Nogo-B expression was demonstrated in the intima of the healthy subjects' subgroup, using immunohistochemistry. WB and real-time PCR revealed a trend toward lower Nogo-B expression in the adventitia of the CVR subgroup. Furthermore, the thickness of the intima was found to negatively correlate with the expression of Nogo-B in the intima and media (r = -0.32; p < 0.05; r = -0.32; p < 0.05). Macrophage infiltrates were more prominent in intima of CVR subjects (0.65 vs 3.52 a.u.; p < 0.01). Macrophage density in intima increased with atherosclerosis progression (r = 0.37; p < 0.01). CD68 macrophages density in adventitia was lower in CVR arteries than in healthy arteries. The expression of Nogo-B, in arterial intima, is impeded in the early stages of atherosclerosis. Accumulation of arterial intimal CD68 macrophages has been shown to progress; however, the overall macrophage density in the adventitia is reduced in arteries shown to have intimal thickening. Macrophage infiltration is not accompanied by Nogo-B expression in atherosclerotic arteries.

The Nogo-B-PirB axis controls macrophage-mediated vascular remodeling

Objective

Nogo-B mediates vascular protection and facilitates monocyte- and macrophage-dependent vascular remodeling. PirB is an alternate receptor for Nogo-B, but a role for the Nogo-PirB axis within the vascular system has not been previously reported. We examined whether Nogo-B or PirB play a role in regulating macrophage-mediated vascular remodeling and hypothesized that endothelial Nogo-B regulates vein graft macrophage infiltration via its alternate receptor PirB.

Methods

Vein grafts were performed using Nogo and PirB wild type and knockout mice. Human vein grafts were similarly analyzed. The hindlimb ischemia model was performed in PirB wild type and knockout mice. Accompanying in vitro work included isolation of macrophages from PirB wild type and knockout mice.

Results

Increased Nogo-B and PirB mRNA transcripts and protein expression were observed within mouse and human vein grafts. Both Nogo knockout and PirB knockout vein grafts showed increased wall thickness and increased numbers of F4/80-positive macrophages. Macrophages derived from PirB knockout mice had increased adhesion to fibronectin, increased EC-specific binding, and increased numbers of mRNA transcripts of M2 markers as well as MMP3 and MMP9. PirB knockout vein grafts had increased active MMP9 compared to wild type vein grafts. PirB knockout mice had increased recovery from hindlimb ischemia and increased macrophage infiltration compared to wild type mice.

Conclusions

Vein graft adaptation shows increased expression of both Nogo-B and PirB. Loss of PirB, or its endothelial ligand Nogo-B, results in increased inflammatory cell infiltration and vein graft wall thickening. These findings suggest that PirB regulates macrophage activity in vein grafts and that Nogo-B in the vein graft limits macrophage infiltration and vein graft thickening. PirB may play a more general role in regulating macrophage responses to vascular injury. Macrophage inhibition via Nogo-PirB interactions may be an important mechanism regulating vein graft adaptation to the arterial circulation.

Integrase-deficient lentiviral vectors mediate efficient gene transfer to human vascular smooth muscle cells with minimal genotoxic risk

We have previously shown that injury-induced neointima formation was rescued by adenoviral-Nogo-B gene delivery. Integrase-competent lentiviral vectors (ICLV) are efficient at gene delivery to vascular cells but present a risk of insertional mutagenesis. Conversely, integrase-deficient lentiviral vectors (IDLV) offer additional benefits through reduced mutagenesis risk, but this has not been evaluated in the context of vascular gene transfer. Here, we have investigated the performance and genetic safety of both counterparts in primary human vascular smooth muscle cells (VSMC) and compared gene transfer efficiency and assessed the genotoxic potential of ICLVs and IDLVs based on their integration frequency and insertional profile in the human genome. Expression of enhanced green fluorescent protein (eGFP) mediated by IDLVs (IDLV-eGFP) demonstrated efficient transgene expression in VSMCs. IDLV gene transfer of Nogo-B mediated efficient overexpression of Nogo-B in VSMCs, leading to phenotypic effects on VSMC migration and proliferation, similar to its ICLV version and unlike its eGFP control and uninfected VSMCs. Large-scale integration site analyses in VSMCs indicated that IDLV-mediated gene transfer gave rise to a very low frequency of genomic integration compared to ICLVs, revealing a close-to-random genomic distribution in VSMCs. This study demonstrates for the first time the potential of IDLVs for safe and efficient vascular gene transfer.

Age-related neointimal hyperplasia is associated with monocyte infiltration after balloon angioplasty

Carotid angioplasty is associated with adverse events in elderly patients; it is unclear whether this is related to an altered inflammatory axis. The carotid arteries of young (6 months) or aged (22-24 months) Fischer 344 rats were balloon injured. Aged rats had reduced lumen area (0.18 ± 0.03 vs 0.24 ± 0.01 mm(2), p = .02) and increased neointimal thickening (0.15 ± 0.04 vs 0.08 ± 0.03 mm(2), p = .006). Aged rats had increased circulating monocytes (96 ± 21 vs. 54 ± 7; p = .002) as well as increased numbers of monocytes at the post-angioplasty site. Aged rats had sustained monocyte chemotactic protein-1 expression after angioplasty but young rats did not. Aged arteries also exhibited defective vasorelaxation and abnormal eNOS localization. Aged (≥80 years) human patients with high-grade carotid stenosis had increased number of monocytes (9.1% ± 0.4%) compared with younger (65-80 years) patients (8.1% ± 0.3%, p = .013). Aged rats develop neointimal hyperplasia after carotid angioplasty with increased numbers of monocytes, and elderly humans with carotid stenosis have increased numbers of circulating monocytes. These preliminary results may suggest a role for monocytes in the response to carotid angioplasty.

Reticulon 4B (Nogo-B) is a novel regulator of hepatic fibrosis

Nogo-B, also known as Reticulon 4B, plays important roles in vascular injuries. Its function in the liver is not understood. The aim of this study was to characterize Nogo-B in liver fibrosis and cirrhosis. Nogo-B distribution was assessed in normal and cirrhotic human liver sections. We also determined the levels of liver fibrosis in wild-type (WT) and Nogo-A/B knockout (NGB KO) mice after sham operation or bile duct ligation (BDL). To investigate the mechanisms of Nogo-B's involvement in fibrosis, hepatic stellate cells were isolated from WT and NGB KO mice and transformed into myofibroblasts. Portal pressure was measured to test whether Nogo-B gene deletion could ameliorate portal hypertension. In normal livers, Nogo-B expression was found in nonparenchymal cells, whereas its expression in hepatocytes was minimal. Nogo-B staining was significantly elevated in cirrhotic livers. Fibrosis was significantly increased in WT mice 4 weeks after BDL compared with NGB KO mice. The absence of Nogo-B significantly reduced phosphorylation of Smad2 levels upon transforming growth factor β (TGF-β) stimulation. Reconstitution of the Nogo-B gene into NGB KO fibroblasts restored Smad2 phosphorylation. Four weeks after BDL, portal pressure was significantly increased in WT mice by 47%, compared with sham-operated controls (P = 0.03), whereas such an increase in portal pressure was not observed in NGB KO mice (P = NS).

CONCLUSION

Nogo-B regulates liver fibrosis, at least in part, by facilitating the TGFβ/Smad2 signaling pathway in myofibroblasts. Because absence of Nogo-B ameliorates liver fibrosis and portal hypertension, Nogo-B blockade may be a potential therapeutic target in fibrosis/cirrhosis.

Epithelial reticulon 4B (Nogo-B) is an endogenous regulator of Th2-driven lung inflammation

The reticulon protein Nogo-B is highly expressed in the lungs, and its loss augments lung inflammation in part as a result of decreased expression of the antiinflammatory protein PLUNC.

Nogo-B is a member of the reticulon family of proteins (RTN-4B) that is highly expressed in lung tissue; however, its function remains unknown. We show that mice with Th2-driven lung inflammation results in a loss of Nogo expression in airway epithelium and smooth muscle compared with nonallergic mice, a finding which is replicated in severe human asthma. Mice lacking Nogo-A/B (Nogo-KO) display an exaggerated asthma-like phenotype, and epithelial reconstitution of Nogo-B in transgenic mice blunts Th2-mediated lung inflammation. Microarray analysis of lungs from Nogo-KO mice reveals a marked reduction in palate lung and nasal clone (PLUNC) gene expression, and the levels of PLUNC are enhanced in epithelial Nogo-B transgenic mice. Finally, transgenic expression of PLUNC into Nogo-KO mice rescues the enhanced asthmatic-like responsiveness in these KO mice. These data identify Nogo-B as a novel protective gene expressed in lung epithelia, and its expression regulates the levels of the antibacterial antiinflammatory protein PLUNC.

Reticulon 4B (Nogo-B) is necessary for macrophage infiltration and tissue repair

Blood vessel formation during ischemia and wound healing requires coordination of the inflammatory response with genes that regulate blood vessel assembly. Here we show that the reticulon family member 4B, aka Nogo-B, is upregulated in response to ischemia and is necessary for blood flow recovery secondary to ischemia and wound healing. Mice lacking Nogo-B exhibit reduced arteriogenesis and angiogenesis that are linked to a decrease in macrophage infiltration and inflammatory gene expression in vivo. Bone marrow-derived macrophages isolated from Nogo knock-out mice have reduced spreading and chemotaxis due to impaired Rac activation. Bone marrow reconstitution experiments show that Nogo in myeloid cells is necessary to promote macrophage homing and functional recovery after limb ischemia. Thus, endogenous Nogo coordinates macrophage-mediated inflammation with arteriogenesis, wound healing, and blood flow control.

Atherosclerotic progression attenuates the expression of Nogo-B in autopsied coronary artery: pathology and virtual histology intravascular ultrasound analysis

The relation of Nogo-B to atherosclerotic plaque progression is not well understood. Thus, the purpose of this study was to assess the expression of Nogo-B in fibroatheromas (FA) of different stages, classified using virtual histology intravascular ultrasound (VH-IVUS) analysis in 19 autopsied cases of non-sudden cardiac death. VH-IVUS imaging analysis was performed 30 mm from the ostium of each coronary artery. VH-IVUS revealed 11 early FAs (34.5+/-8.3 yr), 12 late FAs (42.6+/-16.6 yr), 8 thick-cap FAs (TkCFAs) (46.4+/-11.1 yr), and 6 thin-cap FAs (TCFAs) (51.8+/-6.8 yr). TkCFAs and TCFAs were defined as advanced FA. FA progression advanced with age (P=0.04). VH-IVUS analysis of small, early FAs showed smaller necrotic cores and relatively less calcium compared to more advanced FAs with large necrotic cores (P<0.001). Histopathology and immunohistochemical stains demonstrated that early or late FAs had smaller necrotic cores, less empty space of decalcification, and greater Nogo-B expression compared to advanced FAs (vs. early FA, P=0.013; vs. late FA, P=0.008, respectively). These findings suggest that FA progression is inversely associated with Nogo-B expression. Local reduction of Nogo-B may contribute to plaque formation and/or instability.

In vivo modulation of Nogo-B attenuates neointima formation

Nogo-B was recently identified as a novel vascular marker; the normally high vascular expression of Nogo-B is rapidly lost following vascular injury. Here we assess the potential therapeutic effects of Ad-Nogo-B delivery to injured vessels in vivo. Nogo-B overexpression following Ad-Ng-B infection of vascular smooth muscle cells (VSMCs) was shown to block proliferation and migration in a dose-dependent manner in vitro. We next assessed the effects of Ad-Ng-B treatment on neointima formation in two in vivo models of acute vascular injury. Adventitial delivery of Ad-Ng-B to wire-injured murine femoral arteries led to a significant decrease in the intimal area [0.014 mm(2) versus 0.030 mm(2) (P = 0.049)] and the intima:media ratio [0.78 versus 1.67 (P = 0.038)] as compared to the effects of Ad-beta-Gal control virus at 21 days after injury. Similarly, lumenal delivery of Ad-Ng-B to porcine saphenous veins prior to carotid artery grafting significantly reduced the intimal area [2.87 mm(2) versus 7.44 mm(2) (P = 0.0007)] and the intima:media ratio [0.32 versus 0.55 (P = 0.0044)] as compared to the effects following the delivery of Ad- beta-Gal, at 28 days after grafting. Intimal VSMC proliferation was significantly reduced in both the murine and porcine disease models. Gene delivery of Nogo-B exerts a positive effect on vascular injury-induced remodeling and reduces neointimal development in two arterial and venous models of vascular injury.

Identification of Nogo as a novel indicator of heart failure

Numerous genetically engineered animal models of heart failure (HF) exhibit multiple characteristics of human HF, including aberrant beta-adrenergic signaling. Several of these HF models can be rescued by cardiac-targeted expression of the Gbetagamma inhibitory carboxy-terminus of the beta-adrenergic receptor kinase (betaARKct). We recently reported microarray analysis of gene expression in multiple animal models of HF and their betaARKct rescue, where we identified gene expression patterns distinct and predictive of HF and rescue. We have further investigated the muscle LIM protein knockout model of HF (MLP-/-), which closely parallels human dilated cardiomyopathy disease progression and aberrant beta-adrenergic signaling, and their betaARKct rescue. A group of known and novel genes was identified and validated by quantitative real-time PCR whose expression levels predicted phenotype in both the larger HF group and in the MLP-/- subset. One of these novel genes is herein identified as Nogo, a protein widely studied in the nervous system, where it plays a role in regeneration. Nogo expression is altered in HF and normalized with rescue, in an isoform-specific manner, using left ventricular tissue harvested from both animal and human subjects. To investigate cell type-specific expression of Nogo in the heart, immunofluorescence and confocal microscopy were utilized. Nogo expression appears to be most clearly associated with cardiac fibroblasts. To our knowledge, this is the first report to demonstrate the relationship between Nogo expression and HF, including cell-type specificity, in both mouse and human HF and phenotypic rescue.

Low levels of Nogo-B in human carotid atherosclerotic plaques are associated with an atheromatous phenotype, restenosis, and stenosis severity

OBJECTIVE

Reticulon-4/Nogo (Nogo-B) protects mouse arteries from lumen loss by reducing smooth muscle cell (SMC) migration and intimal thickening. Our goal was to determine plaque and circulating levels of Nogo-B in atherosclerotic and control subjects. Therefore, we studied the relationships between local Nogo-B, plaque characteristics, and clinical data in patients undergoing carotid endarterectomy.

METHODS AND RESULTS

Western blot analysis showed that endarterectomy specimens from the femoral (n=19) and carotid arteries (n=145) contained significantly less Nogo-B than nonatherosclerotic mammary arteries (n=8; P<0.003) and aortas (n=15; P=0.03). Immunohistochemistry revealed that in atherosclerotic lesions, Nogo-B was expressed by macrophage/foam cells, SMC rich, and neo-vascularized areas. Atheromatous plaques (>40% fat content) showed a significant reduction in Nogo-B expression (P=0.002). Nogo-B expression levels were significantly lower in patients with more than 90% of carotid stenosis (P=0.04) or restenotic lesions after prior carotid intervention (duplex; P=0.01). In contrast, plasmatic levels of Nogo-B (soluble Nogo-B) did not differ between atherosclerotic subjects (n=68) and risk-factor matched controls (n=63; P=0.5).

CONCLUSION

Our findings suggest that local reduction of Nogo-B in atherosclerotic tissue might contribute to plaque formation and/or instability triggering luminal narrowing. In contrast, plasma Nogo-B levels are not associated with clinically manifested atherosclerotic disease.