Human Vein Grafts Research Articles

Ex Vivo Magnetic Resonance Imaging Detection of Seeded Adventitial Cells on Human Vein Grafts

Ex Vivo Magnetic Resonance Imaging Detection of Seeded Adventitial Cells on Human Vein Grafts

Phosphorylcholine Monoclonal Antibody Therapy Decreases Intraplaque Angiogenesis and Intraplaque Hemorrhage in Murine Vein Grafts.

Phosphorylcholine (PC) is one of the main oxLDL epitopes playing a central role in atherosclerosis, due to its atherogenic and proinflammatory effects. PC can be cleared by natural IgM antibodies and low levels of these antibodies have been associated with human vein graft (VG) failure. Although PC antibodies are recognized for their anti-inflammatory properties, their effect on intraplaque angiogenesis (IPA) and intraplaque hemorrhage (IPH)-interdependent processes contributing to plaque rupture-are unknown. We hypothesized that new IgG phosphorylcholine antibodies (PC-mAb) could decrease vulnerable lesions in murine VGs.Therefore, hypercholesterolemic male ApoE3*Leiden mice received a (donor) caval vein interposition in the carotid artery and weekly IP injections of (5 mg/kg) PCmAb (n = 11) or vehicle (n = 12) until sacrifice at day 28. We found that PCmAb significantly decreased vein graft media (13%), intima lesion (25%), and increased lumen with 32% compared to controls. PCmAb increased collagen content (18%) and decreased macrophages presence (31%). PCmAb resulted in 23% decreased CD163+ macrophages content in vein grafts whereas CD163 expression was decreased in Hb:Hp macrophages. PCmAb significantly lowered neovessel density (34%), EC proliferation and migration with/out oxLDL stimulation. Moreover, PCmAb enhanced intraplaque angiogenic vessels maturation by increasing neovessel pericyte coverage in vivo (31%). Together, this resulted in a 62% decrease in IPH. PCmAb effectively inhibits murine atherosclerotic lesion formation in vein grafts by reducing IPA and IPH via decreased neovessel density and macrophages influx and increased neovessel maturation. PC-mAb therefore holds promise as a new therapeutic approach to prevent vein graft disease.

Adult Human Vein Grafts Retain Plasticity of Vessel Identity

The spiral saphenous vein graft is an excellent choice for venous reconstruction after periphery vein injury, but only few cases have been reported. We implanted a segment of a single saphenous vein into both the popliteal vein as a venous vein graft and into the popliteal artery as an arterial vein graft at the same time in a trauma patient; we then had an extraordinary opportunity to harvest and examine both patent venous and arterial vein grafts at 2 weeks after implantation. A spiral saphenous vein graft was made as previously described and implanted into the popliteal vein and artery as interposition grafts; because of the patient's serious injuries, an amputation was performed at day 18 after vascular reconstruction. The grafts were harvested, fixed, and examined using histology and immunohistochemistry. Both grafts were patent, and there was a larger neointimal area in the venous graft compared to the arterial graft. There were CD31- and vWF-positive cells on both neointimal endothelia, with subendothelial deposition of α-actin-, CD3-, CD45-, and CD68-positive cells. There were fewer cells in the venous graft neointima compared to the arterial graft neointima; however, there were more inflammatory cells in the neointima of the venous graft. Some of the neointimal cells were PCNA-positive, whereas very few cells were cleaved caspase-3 positive. The venous graft neointimal endothelial cells were Eph-B4 and COUP-TFII positive, while the arterial graft neointimal endothelial cells were dll-4 and Ephrin-B2 positive. The spiral saphenous vein graft remains a reasonable choice for vessel reconstruction, especially in the presence of diameter mismatch. Both the venous and arterial grafts showed similar re-endothelialization and cellular deposition; the venous graft had more neointimal hyperplasia and inflammation. At an early time, endothelial cells showed venous identity in the venous graft, whereas endothelial cells showed arterial identity in the arterial graft. Veins can be used as venous or arterial vein grafts but venous grafts have more neointimal hyperplasia and inflammation; vein grafts acquire different vessel identity depending on the environment into which they are implanted.

Inhibitory Effects of PRG4 on Migration and Proliferation of Human Venous Cells

BackgroundProteoglycan 4 (PRG4; lubricin) is a member of two gene co-expression network modules associated with human vein graft failure. However, little is known about PRG4 and the vascular system. Therefore, we have investigated the effects of recombinant human PRG4 (rhPRG4) on cell migration and proliferation in human veins. MethodsEffects of rhPRG4 on cell migration, proliferation, and neointima formation were determined in human venous tissue and cultured venous smooth muscle cells (SMCs), adventitial cells, and endothelial cells. Expression of PRG4 by cultured human saphenous veins, failed vein grafts, and varicose veins was determined by immunostaining or Western blotting. ResultsLimited expression of PRG4 in fresh saphenous veins was dramatically increased around medial SMCs after culture ex vivo. rhPRG4 inhibited the migration of cultured SMCs, adventitial cells, and endothelial cells, as well as the proliferation of endothelial cells. rhPRG4 also inhibited the migration of SMCs and adventitial cells from tissue explants, but there was no effect on cell proliferation or neointima formation in ex vivo whole veins. Finally, PRG4 was largely absent in two examples of venous pathology, that is, failed human vein grafts and varicose veins. ConclusionsAlthough rhPRG4 can inhibit the migration of venous SMCs, endothelial cells, and adventitial cells, and the proliferation of endothelial cells, PRG4 was only increased around medial SMCs in veins after ex vivo culture. PRG4 was not observed around medial SMCs in failed human vein grafts and varicose veins, suggesting the possibility that a failure of PRG4 upregulation may promote these pathologies.

Activation of Interleukin-1 Beta in Arterialized Vein Grafts and the Influence of the -511C/T IL-1β Gene Polymorphism.

The interleukin-1 family is associated with innate immunity and inflammation. The latter has been linked to the genesis of cardiovascular diseases. We, therefore, investigated whether interleukin-1 beta (IL-1β) is activated during arterialization of vein grafts. First, we examined the activation of IL-1β using the rat arterialized jugular vein serially sampled for up to 90 days. IL-1β expression increased 18 times on day 1 in the arterialized rat jugular vein and remained five times above nonarterialized vein levels for up to 90 days. Similarly, IL-1β expression increased early (1–5 days) in human vein graft autopsy samples compared with late phases (1–4 years). Activation was also detected in ex vivo arterialized human saphenous veins. Upon stratification of the results, we uncovered a T allele promoter attenuating effect in IL-1β activation in response to hemodynamic stress. Altogether, the results show that IL-1β is activated during arterialization of vein grafts in rats and humans, and this response is modulated by -511C/T IL-1β gene polymorphism. It is tempting to speculate that the activation of IL-1β, and consequently local inflammation, modulates early vascular remodeling and that the gene polymorphism may be useful in predicting outcomes or assisting in interventions.

Versican is differentially regulated in the adventitial and medial layers of human vein grafts.

Changes in extracellular matrix proteins may contribute significantly to the adaptation of vein grafts to the arterial circulation. We examined the production and distribution of versican and hyaluronan in intact human vein rings cultured ex vivo, veins perfused ex vivo, and cultured venous adventitial and smooth muscle cells. Immunohistochemistry revealed higher levels of versican in the intima/media compared to the adventitia, and no differences in hyaluronan. In the vasa vasorum, versican and hyaluronan associated with CD34+ progenitor cells. Culturing the vein rings for 14 days revealed increased versican immunostaining of 30–40% in all layers, with no changes in hyaluronan. Changes in versican accumulation appear to result from increased synthesis in the intima/media and decreased degradation in the adventitia as versican transcripts were increased in the intima/media, but unchanged in the adventitia, and versikine (the ADAMTS-mediated cleavage product of versican) was increased in the intima/media, but decreased in the adventitia. In perfused human veins, versican was specifically increased in the intima/media in the presence of venous pressure, but not with arterial pressure. Unexpectedly, cultured adventitial cells express and accumulate more versican and hyaluronan than smooth muscle cells. These data demonstrate a differential regulation of versican and hyaluronan in human venous adventitia vs. intima/media and suggest distinct functions for these extracellular matrix macromolecules in these venous wall compartments during the adaptive response of vein grafts to the arterial circulation.

Blockade of vascular endothelial growth factor receptor 2 inhibits intraplaque haemorrhage by normalization of plaque neovessels.

BackgroundPlaque angiogenesis is associated with atherosclerotic lesion growth, plaque instability and negative clinical outcome. Plaque angiogenesis is a natural occurring process to fulfil the increasing demand of oxygen and nourishment of the vessel wall. However, inadequate formed, immature plaque neovessels are leaky and cause intraplaque haemorrhage.ObjectiveBlockade of VEGFR2 normalizes the unbridled process of plaque neovessel formation and induces maturation of nascent vessels resulting in prevention of intraplaque haemorrhage and influx of inflammatory cells into the plaque and subsequently increases plaque stability.Methods and ResultsIn human carotid and vein graft atherosclerotic lesions, leaky plaque neovessels and intraplaque haemorrhage co‐localize with VEGF/VEGFR2 and angiopoietins. Using hypercholesterolaemic ApoE3*Leiden mice that received a donor caval vein interposition in the carotid artery, we demonstrate that atherosclerotic vein graft lesions at t28 are associated with hypoxia, Hif1α and Sdf1 up‐regulation. Local VEGF administration results in increased plaque angiogenesis. VEGFR2 blockade in this model results in a significant 44% decrease in intraplaque haemorrhage and 80% less extravasated erythrocytes compared to controls. VEGFR2 blockade in vivo results in a 32% of reduction in vein graft size and more stable lesions with significantly reduced macrophage content (30%), and increased collagen (54%) and smooth muscle cell content (123%). Significant decreased VEGF, angiopoietin‐2 and increased Connexin 40 expression levels demonstrate increased plaque neovessel maturation in the vein grafts. VEGFR2 blockade in an aortic ring assay showed increased pericyte coverage of the capillary sprouts.ConclusionInhibition of intraplaque haemorrhage by controlling neovessels maturation holds promise to improve plaque stability.

Invited commentary

Autogenous vein bypass grafting remains an important therapeutic option for patients with peripheral vascular disease. These vein grafts are durable; however, the development of de novo stenosis within the graft occurs in 30% to 50% of patients within the first several years. Despite multiple therapeutic interventions and vein graft manipulations, the incidence of vein graft disease has not changed over the last 30 years. Basic research has focused on endothelial cells, smooth muscle cells, and extracellular matrix as the responsible culprits for the intimal hyperplastic lesion. However, studies have now shown that the adventitial layer may have a more dynamic role in the intimal hyperplastic lesion. Furthermore, recent studies have demonstrated the potential role of genetic variability in the p27 Kip1 gene as a determinant of clinical outcomes in patients with cardiovascular disease and after clinical interventions. The authors present a provocative in vitro study of human venous adventitial and smooth muscle cells that shows that the p27 single nucleotide polymorphism (p27 KIP1-838C>A) is functional and that the levels of p27 messenger RNA and protein were higher in the cells with the AA genotype compared with the CC genotype. Knockdown of p27 increases growth of both cell types with the AA genotype but not those with the CC genotype. What, however, is groundbreaking in their study is the differential effect of the p27 single nucleotide polymorphism on adventitial cell growth. They noted that adventitial cells of the AA genotype grew significantly more slowly than those with the CC genotype. In this study, only the adventitial cells, and not the smooth muscle cells, are responsible to the inhibitory effects of the protective AA genotype in cell growth. The adventitial layer has been noted to have vascular fibroblasts, perivascular adipocytes, and progenitor cells, which have been shown to affect vascular smooth muscle cell phenotype and growth. How these components interact to achieve the complex intimal hyperplastic lesion is still not known. However, using mouse model technology and lineage tracing technology to discover the cells or cells that are really responsible for the intimal hyperplastic lesion and, therefore, more precisely targeting treatment, could one day allow for the treatment of this disease that has been plaguing long-term vascular surgical outcomes for the last 40 years. The opinions or views expressed in this commentary are those of the authors and do not necessarily reflect the opinions or recommendations of the Journal of Vascular Surgery or the Society for Vascular Surgery. A single nucleotide polymorphism of cyclin-dependent kinase inhibitor 1B (p27Kip1) associated with human vein graft failure affects growth of human venous adventitial cells but not smooth muscle cellsJournal of Vascular SurgeryVol. 67Issue 1PreviewCyclin-dependent kinase inhibitor 1B (p27Kip1) is a cell-cycle inhibitor whose -838C>A single nucleotide polymorphism (rs36228499; hereafter called p27 SNP) has been associated with the clinical failure of peripheral vein grafts, but the functional effects of this SNP have not been demonstrated. Full-Text PDF Open Archive

A single nucleotide polymorphism of cyclin-dependent kinase inhibitor 1B (p27Kip1) associated with human vein graft failure affects growth of human venous adventitial cells but not smooth muscle cells

BackgroundCyclin-dependent kinase inhibitor 1B (p27Kip1) is a cell-cycle inhibitor whose -838C>A single nucleotide polymorphism (rs36228499; hereafter called p27 SNP) has been associated with the clinical failure of peripheral vein grafts, but the functional effects of this SNP have not been demonstrated. MethodsHuman saphenous vein adventitial cells and intimal/medial smooth muscle cells (SMCs) were derived from explants obtained at the time of lower extremity bypass operations. We determined the following in adventitial cells and SMCs as a function of the p27 SNP genotype: (1) p27 promoter activity, (2) p27 messenger (m)RNA and protein levels, and (3) growth and collagen gel contraction. Deoxyribonuclease I footprinting was also performed in adventitial cells and SMCs. Resultsp27 promoter activity, deoxyribonuclease I footprinting, p27 mRNA levels, and p27 protein levels demonstrated that the p27 SNP is functional in adventitial cells and SMCs. Both cell types with the graft failure protective AA genotype had more p27 mRNA and protein. As predicted because of higher levels of p27 protein, adventitial cells with the AA genotype grew slower than those of the CC genotype. Unexpectedly, SMCs did not show this genotype-dependent growth response. ConclusionsThese results support the functionality of the p27 SNP in venous SMCs and adventitial cells, but an effect of the SNP on cell proliferation is limited to only adventitial cells. These data point to a potential role for adventitial cells in human vein graft failure and also suggest that SMCs express factors that interfere with the activity of p27.

Abstract 445: Venous Adventitial Cells May Protect Against Human Vein Graft Stenosis

Introduction: A p27 Kip1 single nucleotide polymorphism (SNP) is associated with vein graft failure. The protective genotype (AA) is associated with slower growth of human saphenous vein adventitial cells, but not of smooth muscle cells (SMCs). We investigated the influence of patient clinical characteristics on the migration of adventitial cells and SMCs from vein tissue and the interaction between adventitial cells and SMCs on cell growth. Methods and Results: Tissue explants of the adventitia and intima/media were prepared from samples of vein used for leg bypass, and the number of cells emerging from explants was counted over time (15 replicates/vein, 43 veins). Correlating migration with clinical characteristics of the patient, the degree of leg ischemia was an important factor. Migration of adventitial cells was slower with more severe ischemia (AAI<0.6; N=12) compared to milder ischemia (AAI≥0.6; N= 31): 37.0 ± 4.9 vs 53.8 ± 7.7 cells/explant day 7; mean ± SEM, P<.03). Migration of SMCs from the intima/media explants showed no influence of ischemia (19.1 ± 3.0 vs 24.1 ± 6.1; P=.12). The p27 SNP genotype, diabetes, smoking, and wounds/infection bore no correlation with migration. To test cell interactions, adventitial cells and SMCs from 11 veins were seeded in triplicate on opposite sides of 0.4 um Transwell filters that prevent cell migration (6 AA and 5 CC p27 SNP genotypes), such that the same or different cells were opposed. Cells were counted for a Day4/Day1 proliferation ratio. Compared to AA SMCs, AA adventitial cells significantly inhibited AA SMC growth (10.9 ± 2.5% inhibition; P<.01). In contrast, CC adventitial cells did not significantly inhibit CC SMC growth (4.1 ± 3.5% inhibition, P=.20). Conclusions: Migration of adventitial cells, but not SMCs, from vein tissue is inhibited by increased ischemia. This suggests that adventitial cells may be beneficial, since more severe ischemia has been associated with poorer graft patency. Supporting this, adventitial cells with the protective AA genotype (but not the CC genotype) inhibit the growth of SMCs. These data suggest that adventitial cells and their in situ precursors may inhibit intimal hyperplasia and graft failure by inhibiting SMC proliferation in a p27 SNP genotype-dependent manner.

Apoptosis and autophagy in human vein grafts replacing occluded coronary arteries in atherosclerosis

Atherosclerosis is a chronic disease. For many decades vein grafts are used to replace occluded and suboccluded segments of coronary arteries. Restenosis is still a major problem today, as this chronic disease does not disappear when the occluded segments are replaced by autologous vein grafts. What are the cellular characteristics of this restenosis? Vein grafts obtained during surgical reinterventions were processed for light microscopy, SEM, TEM, immunohistochemistry (nuclear marker, smooth muscle cell marker, ..) and TUNEL (apoptosis).The cellular characteristics are accumulation of foam cells at the luminal side and smooth muscle cell death in the layer underneath. The remaining smooth muscle cells show nuclear fragmentation or apoptosis and remnants of cytoplasmic fragmentation or autophagy. Attempts are being made to develop drugs that might prevent the accumulation of foam cells and smooth muscle cell death in the aim to prevent the redevelopment of atherosclerotic plaques in the vein grafts.

Sphingosine-1-phosphate improves endothelialization with reduction of thrombosis in recellularized human umbilical vein graft by inhibiting syndecan-1 shedding in vitro.

Sphingosine-1phosphate (S1P) is a low molecular-weight phospholipid mediator that regulates diverse biological activities of endothelial cell, including survival, proliferation, cell barrier integrity, and also influences the development of the vascular system. Based on these characters, we the first time to use it as an additive during the process of a small caliber blood vessel construction by decellularized human umbilical vein and endothelial cell/endothelial progenitor. We further explored the function and mechanism of S1P in promoting revascularization and protection against thrombosis in this tissue engineered vascular grafts. The results showed that S1P could not only accelerate the generation but also reduce thrombus formation of small caliber blood vessel.

Cryopreserved Valved Vein Grafts as a Source of Pulmonary Blood Flow

This paper illustrates our technique for using cryopreserved human vein graft with valve as a source of pulmonary blood flow. We illustrate the use of these conduits in the right ventricle to pulmonary artery position, as well as the systemic to pulmonary artery position. Additional illustrated modification is the use of an external stent for both restricting pulmonary blood flow immediately after surgery and increasing pulmonary blood flow as the child experiences somatic growth.

Eph-B4 mediates vein graft adaptation by regulation of endothelial nitric oxide synthase

Vein graft adaptation is characterized by loss of expression of the tyrosine kinase receptor Eph-B4, the embryonic determinant of venous identity, without increased expression of its ligand ephrin-B2, the embryonic determinant of arterial identity. Endothelial nitric oxide synthase (eNOS) is an important mediator of vessel remodeling. We hypothesized that the mechanism of action of Eph-B4 during vein graft adaptation might be through regulation of downstream eNOS activity. Mouse lung endothelial cells were stimulated with ephrin-B2/Fc, without and with preclustering, without and with the eNOS inhibitor Nω-nitro-l-arginine methyl ester hydrochloride or the Eph-B4 inhibitor NVP-BHG712, and assessed by Western blot and immunofluorescence for eNOS and Eph-B4 phosphorylation. Nitric oxide (NO) production was assessed using an NO-specific chemiluminescence analyzer. Cell migration was assessed using a Transwell assay. Human and mouse vein graft specimens were examined for eNOS activity by Western blot, and vessel remodeling was assessed in vein grafts in wild-type or eNOS knockout mice. Ephrin-B2/Fc stimulated both Eph-B4 and eNOS phosphorylation in a bimodal temporal distribution (n= 4; P< .05), with preclustered ephrin-B2/Fc causing prolonged peak Eph-B4 and eNOS phosphorylation as well as altered subcellular localization (n= 4; P< .05). Ephrin-B2/Fc increased NO release (n= 3; P< .01) as well as increased endothelial cell migration (n= 6; P< .05) in an eNOS-dependent fashion. Both human and mouse vein grafts showed increased eNOS phosphorylation compared with normal veins (n= 3; P< .05). Vein grafts from eNOS knockout mice showed less dilation and less wall thickening compared with wild-type vein grafts (n= 7; P< .05). eNOS is a mediator of vein graft adaptation to the arterial environment. Eph-B4 stimulates eNOS phosphorylation in vitro and may mediate vein graft adaptation by regulation of eNOS activity in vivo.

Apoptosis, proliferation, and morphology during vein graft remodeling in rabbits.

Neo-intima development and atherosclerosis limit the long-term use of vein grafts for revascularization of ischemic tissues. Recently, studies have confirmed that proliferating cell nuclear antigen (PCNA) plays an important role in cell proliferation. Our research confirmed that 28 days after vein transplantation, PCNA expression increases significantly. Using rabbits, rather than rodents, for a more representative model of human vein grafts, we aimed to establish a time course of changes in cell proliferation and apoptosis using morphometric and immunohistochemical analyses, western blot, terminal deoxynucleotidyl transferase dUTP nick end labeling, and transmission electron microscopy (TEM). The external jugular veins of 42 healthy purebred male New Zealand white rabbits were grafted onto their common carotid arteries. The rabbits were divided into seven groups, with vein grafts being harvested before surgery, and at 1, 3, 7, 14, 28, and 90 days afterwards. The extent of stenosis and apoptosis, PCNA protein levels, and TEM morphology were subsequently examined. Intimal thickness was slightly decreased 1 day following surgery, but then increased continuously until the 90th day. Western blot and immunohistochemistry both indicated lowered PCNA expression on day 1, although levels subsequently increased, peaking at 7 days post-surgery. After surgery, apoptosis was lowest on day 7, and remained low thereafter. TEM revealed signs of apoptosis as vein graft restenosis progressed. Proliferation and apoptosis co-occurred following grafting, indicating that both processes were involved in vein graft remodeling. Apoptosis levels were highest between days 1 and 3 after surgery, whereas proliferation culminated on the 7th day.

Bromodomain Blockade for Intimal Hyperplasia — A Good BET?

Bromodomain Blockade for Intimal Hyperplasia — A Good BET?

Eph-B4 Mediates Vein Graft Adaptation By Regulation of eNOS

Vein graft adaptation is characterized by loss of expression of the tyrosine kinase receptor ephrin type-B receptor 4 (Eph-B4), the embryonic determinant of venous identity, without increased expression of its ligand ephrin-B2, the embryonic determinant of arterial identity. Endothelial nitric oxide synthase (eNOS) is an important mediator of vessel remodeling. We hypothesized that the mechanism of action of Eph-B4 during vein graft adaptation might be via regulation of downstream eNOS activity. Human and mouse vein graft specimens were examined for eNOS activity by Western blot, and vessel remodeling was assessed in vein grafts in wild-type (WT) or eNOS-knockout (KO) mice. Mouse endothelial cells (EC) were stimulated with ephrin-B2/Fc without and with preclustering, without and with L-NAME (1 mM), and assessed by Western blot and immunofluorescence for eNOS and Eph-B4 phosphorylation. NO production was assessed using a NO-specific chemiluminescence analyzer. Cell migration was assessed using a transwell assay. Human and mouse vein grafts both showed increased eNOS phosphorylation compared with normal veins (n = 3; P < .05). Vein grafts from eNOS-KO mice showed less dilation and less wall thickening compared with WT vein grafts (n = 7; P < .05). Ephrin-B2/Fc stimulated both Eph-B4 and eNOS phosphorylation in a bimodal temporal distribution (n = 4; P < .05), with preclustered ephrin-B2/Fc causing prolonged peak Eph-B4 and eNOS phosphorylation as well as altered subcellular localization (n = 4; P < .05). Ephrin-B2/Fc increased NO release from ECs (n = 3; P < .01) as well as a trend towards increased EC migration (n = 6; P = .11) in an eNOS-dependent fashion. eNOS is a mediator of vein graft adaptation to the arterial environment. Eph-B4 stimulates eNOS phosphorylation and mediates vein graft adaptation by regulation of eNOS activity.

Glycation of extracellular matrix proteins impairs migration of immune cells

The immune response during aging and diabetes is disturbed and may be due to the altered migration of immune cells in an aged tissue. Our study should prove the hypothesis that age and diabetes-related advanced glycation end products (AGEs) have an impact on the migration and adhesion of human T-cells. To achieve our purpose, we used in vitro AGE-modified proteins (soluble albumin and fibronectin [FN]), as well as human collagen obtained from bypass graft. A Boyden chamber was used to study cell migration. Migrated Jurkat T-cells were analyzed by flow cytometry and cell adhesion by crystal violet staining. Actin polymerization was determined by phalloidin-Alexa-fluor 488-labeled antibody and fluorescence microscopy. We found that significantly fewer cells (50%, p = 0.003) migrated through methylglyoxal modified FN. The attachment to FN in the presence of AGE-bovine serum albumin (BSA) was also reduced (p < 0.05). In ex vivo experiments, isolated collagen from human vein graft material negatively affected the migration of the cells depending on the grade of AGE modification of the collagen. Collagen with a low AGE level reduced the cell migration by 30%, and collagen with a high AGE level by 60%. Interaction of the cells with an AGE-modified matrix, but not with soluble AGEs like BSA-AGE per se, was responsible for a disturbed migration. The reduced migration was accompanied by an impaired actin polymerization. We conclude that AGEs-modified matrix protein inhibits cell migration and adhesion of Jurkat T-cells.

The CCR5 chemokine receptor mediates vasoconstriction and stimulates intimal hyperplasia in human vessels in vitro

AimsThe chemokine receptor CCR5 and its inflammatory ligands have been linked to atherosclerosis, an accelerated form of which occurs in saphenous vein graft disease. We investigated the function of vascular smooth muscle CCR5 in human coronary artery and saphenous vein, vascular tissues susceptible to atherosclerosis, and vasospasm.Methods and resultsCCR5 ligands were vasoconstrictors in saphenous vein and coronary artery. In vein, constrictor responses to CCL4 were completely blocked by CCR5 antagonists, including maraviroc. CCR5 antagonists prevented the development of a neointima after 14 days in cultured saphenous vein. CCR5 and its ligands were expressed in normal and diseased coronary artery and saphenous vein and localized to medial and intimal smooth muscle, endothelial, and inflammatory cells. [125I]-CCL4 bound to venous smooth muscle with KD = 1.15 ± 0.26 nmol/L and density of 22 ± 9 fmol mg−1 protein.ConclusionsOur data support a potential role for CCR5 in vasoconstriction and neointimal formation in vitro and imply that CCR5 chemokines may contribute to vascular remodelling and augmented vascular tone in human coronary artery and vein graft disease. The repurposing of maraviroc for the treatment of cardiovascular disease warrants further investigation.

Cathepsin S contributes to macrophage migration via degradation of elastic fibre integrity to facilitate vein graft neointimal hyperplasia

Cathepsin S (Cat S) is a potent lysosomal protease that is secreted into the extracellular space and has been implicated in elastin and collagen degradation in diseases such as atherosclerosis. Elastin degradation plays an important role in vascular remodelling. However, the mechanism by which Cat regulates this process and its contribution to vein graft remodelling remains unclear. Using a murine vein graft model, we examined the expression pattern of Cat family members. Expression of cathepsin genes was induced in vein grafts, with that of Cat S being the highest. Elevated Cat S expression was confirmed in both mouse and human vein grafts. To explore the role of Cat S, vein grafts were created between wild-type (WT) littermates and Cat S knockout (Cat S KO) mice. Knockout of Cat S in the recipients (vein(CatS-KO)-artery(CatS-KO) or vein(WT)-artery(CatS-KO)) significantly inhibited neointima formation and reduced the accumulation of macrophages and proliferation of smooth muscle cells in vein grafts. Knockout of Cat S preserved the elastic fibre integrity of vein grafts and inhibited the migration of macrophages across the elastin fibres. These results demonstrated that Cat S contributes to macrophage migration via degradation of elastic fibre integrity to facilitate neointima formation of vein grafts, which might provide a novel therapeutic target for preserving vein graft patency.