Local Vessel Wall Research Articles

Identification of abdominal aortic aneurysm subtypes based on mechanosensitive genes.

Rupture of abdominal aortic aneurysm (rAAA) is a fatal event in the elderly. Elevated blood pressure and weakening of vessel wall strength are major risk factors for this devastating event. This present study examined whether the expression profile of mechanosensitive genes correlates with the phenotype and outcome, thus, serving as a biomarker for AAA development. In this study, we identified mechanosensitive genes involved in AAA development using general bioinformatics methods and machine learning with six human datasets publicly available from the GEO database. Differentially expressed mechanosensitive genes (DEMGs) in AAAs were identified by differential expression analysis. Molecular biological functions of genes were explored using functional clustering, Protein-protein interaction (PPI), and weighted gene co-expression network analysis (WGCNA). According to the datasets (GSE98278, GSE205071 and GSE165470), the changes of diameter and aortic wall strength of AAA induced by DEMGs were verified by consensus clustering analysis, machine learning models, and statistical analysis. In addition, a model for identifying AAA subtypes was built using machine learning methods. 38 DEMGs clustered in pathways regulating 'Smooth muscle cell biology' and 'Cell or Tissue connectivity'. By analyzing the GSE205071 and GSE165470 datasets, DEMGs were found to respond to differences in aneurysm diameter and vessel wall strength. Thus, in the merged datasets, we formally created subgroups of AAAs and found differences in immune characteristics between the subgroups. Finally, a model that accurately predicts the AAA subtype that is more likely to rupture was successfully developed. We identified 38 DEMGs that may be involved in AAA. This gene cluster is involved in regulating the maximum vessel diameter, degree of immunoinflammatory infiltration, and strength of the local vessel wall in AAA. The prognostic model we developed can accurately identify the AAA subtypes that tend to rupture.

Renal manifestations in vasculitides of small and medium-sized vessels

Small-vessel vasculitides, in particular, are frequently manifested in the kidneys. A distinction is made between antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) and immune complex vasculitides. Even within the AAVs there are differences with respect to renal involvement, which manifest as necrotizing glomerulonephritis (GN) but renal involvement is much rarer in eosinophilic granulomatosis with polyangiitis than in microscopic polyangiitis and granulomatosis with polyangiitis. Disease progression, organ manifestation and prognosis vary according to the ANCA status. In immune complex vasculitides (cryoglobulinemic vasculitis, IgA vasculitis, hypocomplementemic urticarial vasculitis and antiglomerular basement membrane, GBM, disease), endothelial-adjacent activation of neutrophilic granulocytes leads to local vessel wall damage with subsequent ischemic tissue damage, similar to AAV. The sparse evidence of immune complexes is different in pauci-immune AAV. Polyarteritis nodosa is adisease with variable clinical presentations with necrotizing vasculitis of small and medium-sized arteries. Intrarenal aneurysms and hemorrhages but not GN lead to renal damage. Diagnostically, the detection of specific autoantibodies (e.g. anti-GBM), cryoglobulins or increased complement turnover can be decisive. Renal biopsy with qualified immunohistopathology is particularly important in cases of initial manifestation and unclear constellation of findings. The treatment of renal vasculitis is adapted to the severity, stage of disease, extrarenal organ manifestation and pathogenesis. It ranges from glucocorticoid monotherapy to moderate immunosuppression, up to targeted biologic therapy, chemotherapy and plasmapheresis.

Phoenixin-14 alleviates inflammatory smooth muscle cell-induced endothelial cell dysfunction in vitro

BackgroundIntracranial aneurysm (IA) is cerebrovascular disorder which refers to local vessel wall damage to intracranial arteries, forming abnormal bulge. Both endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are closely associated with IA formation and rupture. Inflammatory SMCs (iSMCs) were reported to induce EC dysfunction and result in IA progression. Phoenixin-14 (PNX-14) is a recently discovered brain peptide with pleiotropic roles, which participates in reproduction, cardio protection, lipid deposition and blood glucose metabolism. PNX-14 was previously reported to protect brain endothelial cells against oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cell injury. Therefore, our study was designed to investigate the influence of PNX-14 on iSMCs-induced endothelial dysfunction. MethodsInflammation in SMCs was induced by cyclic mechanical stretch. Human umbilical vein endothelial cells (HUVECs) were exposed to SMC- or iSMC-conditioned medium and then treated with 100 nM PNX-14 for 24 h. The levels of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) in cell supernatants were analyzed by ELISA. Cell viability, apoptosis, angiogenesis and migration were subjected to CCK-8 assay, flow cytometry analysis, tube formation assay and Transwell migration assay. The protein levels of proinflammatory cytokines and apoptosis markers (Bcl-2 and Bax) were evaluated by western blotting. ResultsCyclic mechanical stretch upregulated IL-1β, IL-6 and TNF-α levels in SMCs. Treatment with SMC- or iSMC-conditioned medium HUVECs inhibited cell viability, angiogenesis and migration and induced apoptosis in HUVECs. iSMC-conditioned medium has more significant effects on cell functions. However, the influence of SMC- or iSMC-conditioned medium treatment on HUVEC biological functions were reversed by PNX-14 treatment. PNX-14 exerts no significant influence on the biological functions of HUVECs treated with SMC medium. ConclusionPNX-14 alleviates iSMCs-induced endothelial cell dysfunction in vitro.

Transient behavior and maximum heat flux ratios of two-layer corium pool

In this study, the transient behavior of two-layer corium pool was studied based on COPRA facility. The transient change of two-layer corium pool caused by power change and the effect of stratification and stratified plate thickness on heat transfer characteristics were investigated. Then maximum heat flux ratios (MHFRs) of two-layer corium pools was proposed and investigated using CFD code FLUENT. The heat flux ratio is the ratio of heat flux to qCHF of vessel wall. The maximum of heat flux ratios at all angles is the MHFR of the corium pool. The MHFRs of two-layer corium pool under radiation top surface condition and isothermal top surface condition were obtained. By comparing the values and positions of the MHFRs, the degree of approaching boiling crisis of local reactor pressure vessel wall can be quantitatively analyzed. The results show that MHFR appears at metallic layer wall under radiation top surface condition and at upper part of the oxide layer wall under isothermal top surface condition. The results of this research can provide references for IVR (In-Vessel Retention) safety analysis and ERVC (External-Reactor Vessel Cooling) methods such as Nano-coating measure.

Major adverse cardiovascular events after implantation of absorb bioresorbable scaffold: One-year clinical outcomes

Background/Aim: Bioresorbable vascular scaffold (BVS) represents a novel generation of intracoronary devices designed to be fully resorbed after healing of the stented lesion, delivering antiproliferative drug to suppress restenosis, providing adequate diameter of the coronary vessel and preserving the vascular endothelial function. It was supposed that BVS will reduce neointimal proliferation and that their late bioresorption will reduce the negative effects of traditional drug-eluting stents, including the late stent thrombosis, local vessel wall inflammation, loss of coronary vasoreactivity and the need for the long-term dual antiplatelet therapy. The purpose of this research was to investigate efficacy and safety of Absorb everolimus-eluting BVS implantation and the prevalence of major adverse cardiovascular events (MACE) at the mid-term follow-up. Methods: The study encompassed 42 patients selected for BVS implantation and fulfilling inclusion criteria - 37 male and 5 female - admitted to the Dedinje Cardiovascular Institute, Belgrade, Serbia over the one-year period (from January 2015 to January 2016) for percutaneous coronary intervention (PCI). Coronary vessel patency before and after stenting was assessed by the Thrombolysis in Myocardial Infarction flow (TIMI) grades. After the index PCI procedure with BVS all patients were clinically followed by regular (prescheduled or event-driven) visits during the next 12-month period. Results: In the intention-to-treat analysis, all Absorb BVS procedures were successful, without the need for conversion to other treatment modalities. The complete reperfusion (TIMI flow grade 3) after the intervention was established in 97.6 % of patients and 100 % of them achieved the TIMI flow grade ≥ 2. The presence of angina pectoris was reduced significantly by the BVS procedure: stable angina 57.1 % to 11.9 %, (p < 0.001) and unstable angina 31 % to 0 %, respectively (p < 0.001). After the one-year follow-up, the MACE rate was 11.9 %. Myocardial infarction occurred in 4.8 % and the need for PCI reintervention in 2.4 % of cases (not influenced by the gender or the age of patients). There were 4 cases of death (all patients were older and had lower values of left ventricular ejection fraction). Conclusion: The results of the current research demonstrated a high interventional success rate of the Absorb BVS implantation, followed by the early improvement of the anginal status. However, that was not translated into the favourable mid-term clinical outcomes, opening debate about the current status of Absorb BVS and the need for future refinements of stent design and implantation techniques.

Non‐invasive recanalization of deep venous thrombosis by high frequency ultrasound in a swine model with follow‐up

AimsPulsed cavitational ultrasound therapy (thombotripsy) allows the accurate fractionation of a distant thrombus. We aimed to evaluate the efficacy and safety of non‐invasive thrombotripsy using a robotic assisted and high frequency ultrasound approach to recanalize proximal deep venous thrombosis (DVT) in a swine model. MethodsOcclusive thrombosis was obtained with a dual jugular and femoral endoveinous approach. The therapeutic device was composed of a 2.25 MHz focused transducer centered by a linear ultrasound probe, and a robotic arm. The feasibility, security, and efficacy (venous channel patency) assessment after thrombotripsy was performed on 13 pigs with acute occluded DVT. To assess the mid‐term efficacy of this technique, 8 pigs were followed up for 14 days after thrombotripsy and compared with 8 control pigs. The primary efficacy endpoint was the venous patency. Safety was assessed by the search for local vessel wall injury and pulmonary embolism. ResultsWe succeeded in treating all pigs except two with no accessible femoral vein. After median treatment duration of 23 minutes of cavitation, all treated DVT were fully recanalized acutely. At 14 days, in the treated group, six of the eight pigs had a persistent patent vein and two pigs had a venous reocclusion. In the control group all pigs had a persistent venous occlusion. At sacrifice, no local vein nor arterial wall damage were observed as well as no evidence of pulmonary embolism in all pigs. ConclusionHigh frequency thrombotripsy seems to be effective and safe for non‐invasive venous recanalization of DVT.

The utility of PET/CT in large vessel vasculitis

18F-FDG PET/CT occupies a growing role in the diagnosis of large vessel vasculitis (LVV), illustrating enhanced uptake in the lining of large vessels. A retrospective single center study was conducted of patients who underwent 18F-FDG PET/CT scans between 2009 and 2019 at Sheba Medical Center, Israel. The imaging results were analyzed for evidence of LVV. We reviewed the PET/CT scans of 126 patients and identified 57 studies that either showed evidence of active LVV or that had been performed in patients previously treated for systemic vasculitis. In 6 patients with fevers of unknown origin and elevated inflammatory markers, PET/CT revealed LVV. Six of 13 patients previously treated for systemic vasculitis demonstrated persistent large vessel uptake. LVV was identified in 8 patients with other autoimmune diseases, and in 4 diagnosed with infectious aortitis. In 26 patients who underwent malignancy surveillance, PET/CT revealed more localized large vessel wall inflammation. Our results illustrate that PET/CT may identify large vessel wall inflammation in patients with a suspicion of LVV, and incidentally in patients who undergo malignancy surveillance. PET/CT may also help delineate the presence and extent of vessel inflammation in patients with LVV and in those with other autoimmune diseases.

THE EFFECT OF GOLIMUMAB ON ARTERIAL STIFFNESS IN PATIENTS WITH RHEUMATOID ARTHRITIS

Objective: to evaluate the effect of golimumab (GLM) on arterial stiffness in patients with different clinical and immunological subtypes of rheumatoid arthritis (RA). Material and methods. Examinations were made in 48 patients with RA meeting the 1987 ACR/2010 EULAR classification criteria. The investigators visualized carotid arteries with determination of local vessel wall stiffness and studied regional arterial stiffness with assessment of contour pulse wave analysis before and 52 weeks after initiation of therapy. Results and discussion . Young and middle-aged RA patients without any concomitant cardiovascular diseases were found to have subclinical great artery involvement that was characterized by increases in intima-media thickness (IMT) and stiffness index β of the common carotid artery (CCA); by rises in peripheral augmentation index (AIp), stiffness index (SI), and reflection index (RI), the intensity of a change in which was associated with high DAS28 and seropositivity for rheumatoid factor (RF) and/or anti-cyclic citrullinated peptide (antiCCP) antibodies. GLM treatment in patients with RA was accompanied by a statistically significant decrease in DAS28 and a reduction in CCA IMT and local (carotid) stiffness of the vascular bed. More significant correction of the investigated parameters was achieved in patients with the seronegative subtype of the disease; in this group of patients, CCA IMT decreased by 29% by the end of observation (p=0.01), CCA SI β reduced by an average of 28.7% (p=0.0001). At 52 weeks after GLM therapy initiation, contour pulse wave analysis indicated that this subgroup of patients was observed to have decreases in AIp, SI, and RI to the control level; in RA seropositive for RF and/or anti-CCP, they reduced by an average of 1.8 (p=0.0001), 1.2 (p=0.005) and 1.6 (p=0.001) times, respectively. Conclusion. Along with high anti-inflammatory activity, GLM therapy in patients with RA has a vasoprotective effect on the walls of large elastic-type vessels (decreases in CCA IMT and SI β, AIp, and SI) and small muscular-type arteries (a reduction in RI).

High-speed photographic observation of the sonication of a rabbit carotid artery filled with microbubbles by 20-kHz low frequency ultrasound

The aim of this study is to assess the physical damage of cavitation effects induced by low frequency ultrasound and microbubbles (MBs) to an in vitro vessel. A rabbit carotid artery filled with SonoVue MBs and methylene blue was irradiated with 20-kHz ultrasound, and the results were recorded by high-speed photography at 3000 frames per second. The carotid artery filled with MBs experienced a slight tremor during ultrasonication. Six intermittent blue flow events occurred in two places on the artery wall during the 5-s process. The duration of each leakage event was 90–360ms with an average of 200ms. Hematoxylin-eosin (H-E) staining demonstrated the separation of the carotid artery elastic membrane, local blood vessel wall defects and hole formation, and the surface of the ruptured area was rough and irregular. Another carotid artery was filled with a 0.9% NaCl solution and methylene blue as a control and irradiated with 20-kHz ultrasound. No blue liquid flow was seen, and no holes in the vessel were observed. H-E staining revealed intact vascular endothelial cells and smooth muscles with no vascular wall defects. Low-frequency ultrasound combined with MBs can cause a vessel to rupture and holes to form in a short time. High-speed photography is useful for observing transient changes caused by the effects of ultrasound cavitation on an in vitro vessel.

Sensitive three-dimensional ultrasound assessment of carotid atherosclerosis by weighted average of local vessel wall and plaque thickness change.

Vitamin B deficiency has been identified as a risk factor for vascular events. However, the reduction of vascular events was not shown in large randomized controlled trials evaluating B-Vitamin therapy. There is an important requirement to develop sensitive biomarkers to be used as efficacy targets for B-Vitamin therapy as well as other dietary treatments and lifestyle regimes that are being developed. Carotid vessel-wall-plus-plaque thickness change (VWT-Change) measured from 3D ultrasound has been shown to be sensitive to atorvastatin therapies in previous studies. However, B-Vitamin treatment is expected to confer a smaller beneficial effect in carotid atherosclerosis than the strong dose of atorvastatin. This paper introduces a sensitive atherosclerosis biomarker based on the weighted mean VWT-Change measurement from 3D ultrasound with a purpose to detect statistically significant effect of B-Vitamin therapy. Of the 56 subjects analyzed in this study, 27 were randomized to receive a B-Vitamin tablet daily and 29 received a placebo tablet daily. Participants were scanned at baseline and 1.9 ± 0.8 yr later. The 3D VWT map at each scanning session was computed by matching the outer wall and lumen surfaces on a point-by-point basis. The 3D annual VWT-Change maps were obtained by first registering the 3D VWT maps obtained at the baseline and follow-up scanning sessions, and then taking the point-wise difference in VWT and dividing the result by the years elapsed from the baseline to the follow-up scanning session. The 3D VWT-Change maps constructed for all patients were mapped to a 2D carotid template to adjust for the anatomic variability of the arteries. A weight at each point of the carotid template was assigned based on the degree of correlation between the VWT-Change measurements exhibited at that point and the treatment received (i.e., B-Vitamin or placebo) quantified by mutual information. The weighted mean of VWT-Change for each patient, denoted by ΔVWT¯Weighted, was computed according to this weight. T-tests were performed to compare the sensitivity of ΔVWT¯Weighted with existing biomarkers in detecting treatment effects. These biomarkers included changes in intima-media thickness (IMT), total plaque area (TPA), vessel wall volume (VWV), unweighted average of VWT-Change (ΔVWT¯) and a previously described biomarker, denoted by ΔVWT¯S, that quantifies the mean VWT-Change specific to regions of interest identified by a feature selection algorithm. Among the six biomarkers evaluated, the effect of B Vitamins was detected only by ΔVWT¯Weighted in this cohort (P=4.4×10-3). The sample sizes per treatment group required to detect an effect as large as exhibited in this study were 139, 178, 41 for ΔVWV, ΔVWT¯ and ΔVWT¯Weighted respectively. The proposed weighted mean of VWT-Change is more sensitive than existing biomarkers in detecting treatment effects. This measurement tool will allow for many proof-of-principal studies to be performed for various novel treatments before a more costly study involving a larger population is held to validate the results.

Neointimal coverage on acute vessel wall injuries after stenting: 6-month follow-up study.

Stent implantation often creates local vessel wall injuries which can be characterized in detail by optical coherence tomography (OCT). Little is known about the neointimal coverage at these areas. We aimed to evaluate neointimal coverage of vessel wall injuries area associated with stent implantation. We retrospectively selected patients implanted with sirolimus-eluting stents (SES) having excellent OCT images immediately after stent implantation and at the 6-month follow-up. All OCT cross-sectional images were divided into three groups: intra-stent tissue prolapse (ISTP) areas, intra-stent dissection flaps (ISDF) areas, and non-injuried areas. The neointimal coverage in included sections was evaluated at 6 months follow-up. Finally, 1690 cross-sectional images in 74 stents were analyzed totally. Among which, 240 images (14.20%) involved ISTP areas, 124 images (7.34%) at ISDF areas, and 1326 images (78.46%) at non-injuried areas. All ISTP and ISDF were disappeared at six months follow-up, Neointimal thickness at ISTP and ISDF areas increased significantly compared to the one in non-injuried areas (97.4±40.3μm vs. 68.4±47.6μm, P<0.001; 92.7±49.8μm vs. 68.4±47.6μm, P<0.001). Mean neointimal area of ISTP and ISDF areas was almost the same (0.8±0.3 mm2), which both had a significant difference compared to mean neointimal area (0.6±0.4mm2) at non-injuried areas (p1<0.001, p2=0.006). Intra-stent tissue prolapse and intra-stent dissection flaps have benign clinical course up to 6 months. The areas with these local complications, however, have greater neointimal hyperplasia compared to the non-injuried areas.

Impaired vascular function and repair in patients with premature coronary artery disease.

Endothelial dysfunction is central to the pathogenesis of coronary artery disease, but the role of local and circulating endothelial progenitor cells in maintaining vascular health is poorly understood. We hypothesised that impaired local and circulating vascular repair mechanisms predispose to endothelial dysfunction and the premature onset of coronary artery disease. Patients with premature coronary artery disease (n = 16) and healthy age- and sex-matched controls (n = 16) underwent venous occlusion plethysmography with intra-arterial infusion of acetylcholine and sodium nitroprusside. Numbers of circulating endothelial progenitor cells were directly quantified in whole blood by flow cytometry. Endothelial cells were isolated from the blood vessel wall and from peripheral blood mononuclear cells, and expanded invitro for phenotypic and functional characterisation and analysis of microRNA expression levels. A dose-dependent increase in forearm blood flow (p < 0.001) was attenuated in response to the endothelial-dependent vasodilator acetylcholine in patients compared with controls (p = 0.03). No differences in the number of circulating endothelial progenitor cells or in the phenotype, function or microRNA expression levels of endothelial outgrowth cells isolated from blood were observed in patients and controls. Conversely, local vessel wall endothelial cells from patients had significant impairments in proliferation, adhesion and migration, and significantly reduced expression levels of microRNAs known to regulate endothelial function (miRs -10 a, -let7b, -126 and -181 b) (p < 0.05 for all). Local vessel wall derived endothelial cells, rather than circulating endothelial progenitor cells and their progeny, are impaired in patients with vascular dysfunction and premature coronary artery disease.

Interleukin-1 potently contributes to 25-hydroxycholesterol-induced synergistic cytokine production in smooth muscle cell-monocyte interactions

Objectives: Inflammation is essential for atherogenesis. Cholesterol, a cardiovascular risk factor, may activate inflammation in the vessel wall during this process. Cytokine-mediated interactions of human monocytes with vascular smooth muscle cells (SMCs) may perpetuate this process. Methods: We investigated the capacity of the cholesterol metabolite 25-hydroxycholesterol to induce inflammatory mediators in cocultures of freshly isolated monocytes with SMCs. We determined the role of interleukin-(IL)-1 in this interaction using qPCR, bioassays, ELISA and western blot. Cocultures with SMC to monocyte ratios from 1:4 to 1:20 were tested. Results: In separate SMC and monocyte cultures (monocultures) 25-hydroxycholesterol only poorly activated IL-1, IL-6 and MCP-1 production, whereas LPS stimulated much higher cytokine levels than unstimulated cultures. In contrast, cocultures of SMCs and monocytes stimulated with 25-hydroxycholesterol produced hundredfold higher cytokine levels than the corresponding monocultures. Blocking experiments with IL-1-receptor antagonist showed that IL-1 decisively contributed to the 25-hydroxycholesterol-induced synergistic IL-6 and MCP-1 production. The presence of intracellular IL-1β precursor, released mature IL-1β, and caspase-1 p10 indicated that the inflammasome was involved in this process. Determination of IL-1-mRNA in Transwell experiments indicated that the monocytes are the major source of IL-1, which subsequently activates the SMCs, the primary source of IL-6 in the coculture. Conclusion: Taken together, these interactions between local vessel wall cells and invading monocytes may multiply cholesterol-triggered inflammation in the vessel wall, and IL-1 may play a key role in this process. The data also indicate that lower cholesterol levels than expected from monocultures may suffice to initiate inflammation in the tissue.

Quantification and visualization of carotid segmentation accuracy and precision using a 2D standardized carotid map

This paper describes a framework for vascular image segmentation evaluation. Since the size of vessel wall and plaque burden is defined by the lumen and wall boundaries in vascular segmentation, these two boundaries should be considered as a pair in statistical evaluation of a segmentation algorithm. This work proposed statistical metrics to evaluate the difference of local vessel wall thickness (VWT) produced by manual and algorithm-based semi-automatic segmentation methods (ΔT) with the local segmentation standard deviation of the wall and lumen boundaries considered. ΔT was further approximately decomposed into the local wall and lumen boundary differences (ΔW and ΔL respectively) in order to provide information regarding which of the wall and lumen segmentation errors contribute more to the VWT difference. In this study, the lumen and wall boundaries in 3D carotid ultrasound images acquired for 21 subjects were each segmented five times manually and by a level-set segmentation algorithm. The (absolute) difference measures (i.e., ΔT, ΔW, ΔL and their absolute values) and the pooled local standard deviation of manually and algorithmically segmented wall and lumen boundaries were computed for each subject and represented in a 2D standardized map. The local accuracy and variability of the segmentation algorithm at each point can be quantified by the average of these metrics for the whole group of subjects and visualized on the 2D standardized map. Based on the results shown on the 2D standardized map, a variety of strategies, such as adding anchor points and adjusting weights of different forces in the algorithm, can be introduced to improve the accuracy and variability of the algorithm.

Uremic Serum and Solutes Increase Post–Vascular Interventional Thrombotic Risk Through Altered Stability of Smooth Muscle Cell Tissue Factor

Stent thrombosis (ST), a postinterventional complication with a mortality rate of 50%, has an incidence that rises precipitously in patients at risk. Chronic renal failure and end-stage renal disease have emerged as particularly strong ST risk factors, yet the mechanism remains elusive. Tissue factor (TF) is a crucial mediator of injury-related thrombosis and has been implicated for ST. We posit that uremia modulates TF in the local vessel wall to induce postinterventional thrombosis in patients with end-stage renal disease. As a model of the de-endothelialized, postinterventional state, we exposed primary human vascular smooth muscle cells (vSMCs) pretreated with uremic serum (obtained from ESRD patients on hemodialysis) to coronary-like blood flow. vSMC TF expression, activity, stability, and posttranslational modification were examined after vSMCs were treated with uremic serum or solutes. We found significantly greater clot formation after uremic serum exposure, which was substantially reduced with the prior treatment with anti-TF neutralizing antibody. Uremic sera induced 2- to 3-fold higher TF expression and activity in vSMCs independent of diabetes mellitus. Relevant concentrations of isolated uremic solutes such as indole-3-acetic acid (3.5 μg/mL), indoxyl sulfate (25 μg/mL), and uric acid (80 μg/mL) recapitulated these effects in cell culture and the flow loop model. We show further that TF undergoes ubiquitination at baseline and that uremic serum, indole-3-acetic acid, and indoxyl sulfate significantly prolong TF half-life by inhibiting its ubiquitination. The uremic milieu is profoundly thrombogenic and upregulates vSMC TF levels by increasing TF stability and decreasing its ubiquitination. Together, these data demonstrate for the first time that the posttranslational regulation of TF in uremia may have a causative role in the increased ST risk observed in uremic patients. These data suggest that interventions that reduce vSMC TF may help to prevent ST and that uremic solutes should be considered as novel risk factors for ST in patients with chronic renal failure.

Contribution of vascular cell-derived cytokines to innate and inflammatory pathways in atherogenesis.

Inflammation is a central element of atherogenesis. Innate pathways contribute to vascular inflammation. However, the initial molecular process(es) starting atherogenesis remain elusive. The various risk factors, represented by particular compounds (activators), may cause altered cellular functions in the endothelium (e.g. vascular endothelial cell activation or -dysfunction), in invading cells (e.g. inflammatory mediator production) or in local vessel wall cells (e.g. inflammatory mediators, migration), thereby triggering the innate inflammatory process. The cellular components of innate immunology include granulocytes, natural killer cells and monocytes. Among the molecular innate constituents are innate molecules, such as the toll-like receptors or innate cytokines. Interleukin-1 (IL-1) and IL-6 are among the innate cytokines. Cytokines are potent activators of a great number of cellular functions relevant to maintain or commove homeostasis of the vessel wall. Within the vessel wall, vascular smooth muscle cells (SMCs) can significantly contribute to the cytokine-dependent inflammatory network by: (i) production of cytokines, (ii) response to cytokines and (iii) cytokine-mediated interaction with invading leucocytes. The cytokines IL-1 and IL-6 are involved in SMC-leucocyte interaction. The IL-6 effects are proposed to be mediated by trans-signalling. Dysregulated cellular functions resulting from dysregulated cytokine production may be the cause of cell accumulation, subsequent low-density lipoprotein accumulation and deposition of extracellular matrix (ECM). The deposition of ECM, increased accumulation of leucocytes and altered levels of inflammatory mediators may constitute an ‘innate-immunovascular-memory’ resulting in an ever-growing response to anew invasion. Thus, SMC-fostered inflammation, promoted by invading innate cells, may be a potent component for development and acceleration of atherosclerosis.

Smooth muscle cells in porcine vein graft intimal hyperplasia are derived from the local vessel wall.

Accelerated intimal hyperplasia (IH) is an important cause of morbidity and mortality in patients with atherosclerotic vascular disease treated with bypass vein grafts. We used an interposition vein graft model to determine the source of neointimal cells in a clinically relevant large animal model. Jugular vein segments from sex-mismatched, MHC-in-bred pigs were implanted into common carotid arteries bilaterally and harvested up to 8 weeks postsurgery for stereological, histological, and immunofluorescence analyses. Progressive IH lesions contained macrophages and smooth muscle cells (SMC). Fluorescent in situ hybridization following grafting of female veins into male arteries revealed that only ∼10% of the SMC were male, confirming that the majority of intimal SMC derived from the local vessel wall. The majority of neointimal SMC in the IH seen after interposition vein grafting derive from the engrafted local vessel wall. These are the first results from a clinically relevant large animal model that confirm data from rodent models. They have implications for the utility of therapeutic stem cells in this type of intimal hyperplasia.

32 Intravascular large B-cell lymphoma: clinicopathological study of seven cases

Angiotropic large cell lymphoma is a rare neoplastic disorder associated with a high mortality. The hallmark of the disease is lymphoid proliferation confined to the intravascular compartment without local tissue or vessel wall infiltration [1]. This feature is so striking that the disease was originally thought to arise from endothelial tissue and early cases were described as malignant angioendotheliomatosis. However, application of immunohistochemical methods for detection of lymphoid markers such as the CD45 and CD20 cell surface markers has confirmed its lymphoid origin, usually of B-cell lineage [2]. Clinical manifestations of the disease are protean and are due to multifocal medium and small vessel occlusion by tumour cells [3]. Characteristic sites of involvement are skin and central nervous system and although an ante-mortem diagnosis can be made from a biopsy specimen, it is often unsuspected [4]. We present a case of angiotropic large B-cell lymphoma in a 74-year-old man who presented with urinary symptoms and had a neurological picture resembling subacute combined degeneration of the cord.

Signs of Accelerated Preclinical Atherosclerosis in Patients with Ankylosing Spondylitis

Preliminary evidence suggests that ankylosing spondylitis (AS) is associated with an increased cardiovascular (CV) risk. We investigated subclinical atherosclerosis and arterial stiffness in patients with AS compared with controls, and identified CV and AS related risk factors for atherosclerotic disease. A total of 59 patients with AS who were scheduled for etanercept treatment according to the ASsessments in Ankylosing Spondylitis guidelines and 30 healthy controls were recruited. Subclinical atherosclerosis was assessed as the average intima-media thickness (IMT) of the common carotid artery. Arterial stiffness was determined by distensibility, compliance, and Young's elastic modulus of the carotid artery. AS patients had a greater IMT (0.62 +/- 0.09 mm vs 0.57 +/- 0.09 mm in controls; p = 0.02), a difference that remained after adjustment for traditional CV risk factors. AS was associated with higher carotid pulse pressure (47 +/- 7 mm Hg vs 44 +/- 8 mm Hg in controls; p = 0.04), but this was not due to local vessel wall properties. Among AS patients, age and body mass index (BMI) were determinants of IMT. Age, BMI, total cholesterol, triglycerides, and disease duration were identified as determinants of stiffness indices. No relationship was found between large-vessel properties and higher Bath AS disease indices or C-reactive protein values. AS was associated with subclinical atherosclerosis and arterial stiffness, supporting epidemiological evidence of an increased CV risk in these patients. Whether these differences are due to AS or to a higher prevalence of CV risk factors in patients with AS remains to be determined.

Initial feasibility of a multi‐station high resolution three‐dimensional dark blood angiography protocol for the assessment of peripheral arterial disease

To evaluate the feasibility of a multi-station three dimensional (3D) T1-weighted turbo spin echo (TSE) dark-blood Sampling Perfection with Application optimized Contrasts using different flip angle Evolution sequence (T1w-SPACE), to assess aorta, iliac, and superficial femoral (SFA) arteries (inflow vessels) by comparing it with a multi-station contrast enhanced MR angiography (CE-MRA) with identical resolution. A total of 6 volunteers and 14 peripheral arterial disease (PAD) patients were included in the study. Abdominal and thigh T1w-SPACE and lower leg time-resolved MRA (TR-MRA) with low dose contrast were followed by 3-station CE-MRA. Quantitative measurements of lumen area at 17 locations from T1w-SPACE and CE-MRA were obtained. Additionally, vessel wall areas at the same locations were obtained from the T1w-SPACE images. Quantitative comparison of lumen areas with T1w-SPACE and CE-MRA revealed strong correlation between the two techniques and strong inter-observer agreement for each of the two imaging methods (r > 0.9; P < 0.001). Localized vessel wall area measurements obtained in PAD patients were significantly greater compared with those obtained in normal volunteers (mean difference 43.75 +/- 12.46 mm(2); P < 0.001). Stenosis severity obtained from T1w-SPACE localized measurements showed significant arterial area stenosis in PAD patients. T1w-SPACE imaging of inflow vessels is feasible, and in addition to CE-MRA has the ability to assess atherosclerotic plaque and vascular remodeling.