transforming-growth-factor-beta and Neointima

Chronic kidney disease (CKD) accelerates the development of neointima formation at the anastomosis site of arteriovenous (AV) fistulas. Accumulation of certain uremic toxins has a deleterious effect on the cardiovascular system. The oral charcoal adsorbent, AST-120, reduces circulating and tissue uremic toxins, but its effect on neointima formation at an AV fistula is unknown. To understand the effect of CKD and AST-120 on neointima formation, we created AV fistulas (common carotid artery to the external jugular vein in an end-to-side anastomosis) in mice with and without CKD. AST-120 was administered in chow before and after AV fistula creation. Administration of AST-120 significantly decreased serum indoxyl sulfate levels in CKD mice. CKD mice had a larger neointima area than non-CKD mice, and administration of AST-120 in CKD mice attenuated neointima formation. Both smooth muscle cell and fibrin components were increased in CKD mice, and AST-120 decreased both. RNA expression of MMP-2, MMP-9, TNFα, and TGFβ was increased in neointima tissue of CKD mice, and AST-120 administration neutralized the expression. Our results provided in vivo evidence to support the role of uremic toxin-binding therapy on the prevention of neointima formation. Peri-operative AST-120 administration deserves further investigation as a potential therapy to improve AV fistula patency.

Topics: Administration, Oral; Adsorption; Animals; Arteriovenous Shunt, Surgical; Carbon; Collagen; Disease Models, Animal; Graft Occlusion, Vascular; Indican; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Neointima; Oxides; Renal Insufficiency, Chronic; Toxins, Biological; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Uremia; Vascular Patency

Mutations in the PTPN11 gene, which encodes the protein tyrosine phosphatase Shp2, cause Noonan syndrome and LEOPARD syndrome, inherited multifaceted diseases including cardiac and vascular defects. However, the function of Shp2 in blood vessels, especially in vascular smooth muscle cells (VSMCs), remains largely unknown. We generated mice in which Shp2 was specifically deleted in VSMCs and embryonic cardiomyocytes using the SM22α-Cre transgenic mouse line. Conditional Shp2 knockout resulted in massive hemorrhage, cardiovascular defects and embryonic lethality at the late embryonic developmental stage (embryonic date 16.5). The thinning of artery walls in Shp2-knockout embryos was due to decreased VSMC number and reduced extracellular matrix deposition. Myocyte proliferation was decreased in Shp2-knockout arteries and hearts. Importantly, cardiomyocyte-specific Shp2-knockout did not cause similar vascular defects. Shp2 was required for TGFβ1-induced expression of ECM components, including collagens in VSMCs. In addition, collagens were sufficient to promote Shp2-inefficient VSMC proliferation. Finally, Shp2 was deleted in adult mouse VSMCs by using SMMHC-CreER

Topics: Animals; Carotid Arteries; Cell Proliferation; Collagen; Cyclin D1; Embryo, Mammalian; Extracellular Matrix; Female; Heart; Hemorrhage; Integrases; Male; Mice, Knockout; Muscle, Smooth, Vascular; Myocardium; Myocytes, Smooth Muscle; Neointima; Protein Tyrosine Phosphatase, Non-Receptor Type 11; Rats; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta

Vascular access stenosis predominantly occurs as a result of neointimal hyperplasia (NH) formation at the anastomosis. Moreover, in the presence of NH, transforming growth factor-beta (TGF-β) promotes vascular smooth muscle cell (VSMC) proliferation. Extracellular vesicles (EVs) released by endothelial cells are closely associated with vascular dysfunction. Here, we investigated the effects of EVs on TGF-β signaling and VSMC proliferation. Specifically, EVs were collected from the culture medium of indoxyl sulfate (IS)-treated human umbilical vein endothelial cells and used (2 × 106) to stimulate human aortic smooth muscle cells (SMCs) (1 × 106). Western blotting was performed to assess the levels of Akt, ERK1/2, p38 MAPK, and Smad3. BrdU proliferation assays, quantitative PCR, and ELISA assays were performed to evaluate SMC proliferation and TGF-β production. The IS-induced EVs stimulated the proliferation of aortic SMCs in a concentration-dependent manner. The EVs both contained TGF-β and promoted TGF-β production by SMCs by phosphorylating Akt, ERK1/2, p38 MAPK, and Smad3, which was significantly inhibited by an anti-TGF-β antibody. SMC proliferation was suppressed by both an anti-TGF-β antibody and inhibitors of the downstream factors. These results suggest that EVs are involved in the pathogenesis of vascular access stenosis by modulating TGF-β signaling in VSMCs under uremic conditions.

Topics: Cell Proliferation; Cells, Cultured; Extracellular Signal-Regulated MAP Kinases; Extracellular Vesicles; Human Umbilical Vein Endothelial Cells; Humans; Indican; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; p38 Mitogen-Activated Protein Kinases; Paracrine Communication; Phosphorylation; Proto-Oncogene Proteins c-akt; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta; Uremia

The production of growth factors from several experimental arterial conduits was determined.. We implanted 105 experimental arterial grafts that were 1 cm long in the abdominal aorta of Lewis rats (average weight, 250 g). Five different types of grafts were analyzed: arterial isografts, vein grafts, arterial allografts, and polytetrafluoroethylene (PTFE) grafts with normal or decreased compliance. Animals were killed humanely 4 weeks after surgery and the production of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), transforming growth factor-β, tumor necrosis factor-α, and interleukin-1 was analyzed.. Myointimal hyperplasia (MH) was evident in vein grafts, arterial allografts, and PTFE grafts, but not in arterial isografts. Growth factor production was increased for grafts prone to develop MH like vein, PTFE grafts, and arterial allografts. PDGF and bFGF were increased significantly for PTFE and vein grafts, but not for arterial allografts. The importance of bFGF and PGDF was confirmed by the capability of antibody to PDGF and to bFGF to reduce the mitogenic activity of smooth muscle cells, in vivo and in vitro, for PTFE and vein grafts, but not for arterial allografts, in which a predominant role was played by interleukin-1 and tumor necrosis factor-α.. Agents able to neutralize this increased production of growth factors, either directly or by competition with their receptors, can prevent MH formation.

Topics: Allografts; Animals; Aorta, Abdominal; Arteries; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation; Cell Proliferation; Cells, Cultured; Culture Media, Conditioned; Fibroblast Growth Factor 2; Hyperplasia; Intercellular Signaling Peptides and Proteins; Interleukin-1; Isografts; Models, Animal; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; Platelet-Derived Growth Factor; Polytetrafluoroethylene; Prosthesis Design; Rats, Inbred Lew; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Veins

Endovascular interventions performed for atherosclerotic lesions trigger excessive vascular smooth muscle cell (SMC) proliferation leading to intimal hyperplasia. Our previous studies show that following endovascular injury, elevated TGF-β/Smad3 promotes SMC proliferation and intimal hyperplasia. Furthermore in cultured SMCs, elevated TGF-β/Smad3 increases the expression of several Wnt genes. Here we investigate a crosstalk between TGF-β/Smad3 and Wnt/β-catenin signaling and its role in SMC proliferation.. To mimic TGF-β/Smad3 up-regulation in vivo, rat aortic SMCs were treated with Smad3-expressing adenovirus (AdSmad3) or AdGFP control followed by stimulation with TGF-β1 (or solvent). AdSmad3/TGF-β treatment up-regulated Wnt2b, Wnt4, Wnt5a, Wnt9a, and Wnt11 (confirmed by qRT-PCR and ELISA), and also increased β-catenin protein as detected by Western blotting. Blocking Wnt signaling using a Frizzled receptor inhibitor (Niclosamide) abolished TGF-β/Smad3-induced β-catenin stabilization. Increasing β-catenin through degradation inhibition (using SKL2001) or by adenoviral expression enhanced SMC proliferation. Furthermore, application of recombinant Wnt2b, Wnt4, Wnt5a, or Wnt9a, but not Wnt11, stabilized β-catenin and stimulated SMC proliferation as well. In addition, increased β-catenin was found in the neointima of injured rat carotid artery where TGF-β and Smad3 are known to be up-regulated.. These results suggest a novel mechanism whereby elevated TGF-β/Smad3 stimulates the secretion of canonical Wnts which in turn enhances SMC proliferation through β-catenin stabilization. This crosstalk between TGF-β/Smad3 and Wnt/β-catenin canonical pathways provides new insights into the pathophysiology of vascular SMCs linked to intimal hyperplasia.

Topics: Animals; Aorta; beta Catenin; Carotid Artery Diseases; Cell Proliferation; Male; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; Rats, Sprague-Dawley; Smad3 Protein; Transforming Growth Factor beta; Wnt Proteins; Wnt Signaling Pathway

CXCR4 is a stem/progenitor cell surface receptor specific for the cytokine stromal cell-derived factor-1 (SDF-1α). There is evidence that bone marrow-derived CXCR4-expressing cells contribute to intimal hyperplasia (IH) by homing to the arterial subintima which is enriched with SDF-1α. We have previously found that transforming growth factor-β (TGFβ) and its signaling protein Smad3 are both upregulated following arterial injury and that TGFβ/Smad3 enhances the expression of CXCR4 in vascular smooth muscle cells (SMCs). It remains unknown, however, whether locally induced CXCR4 expression in SM22 expressing vascular SMCs plays a role in neointima formation. Here, we investigated whether elevated TGFβ/Smad3 signaling leads to the induction of CXCR4 expression locally in the injured arterial wall, thereby contributing to IH. We found prominent CXCR4 upregulation (mRNA, 60-fold; protein, 4-fold) in TGFβ-treated, Smad3-expressing SMCs. Chromatin immunoprecipitation assays revealed a specific association of the transcription factor Smad3 with the CXCR4 promoter. TGFβ/Smad3 treatment also markedly enhanced SDF-1α-induced ERK1/2 phosphorylation as well as SMC migration in a CXCR4-dependent manner. Adenoviral expression of Smad3 in balloon-injured rat carotid arteries increased local CXCR4 levels and enhanced IH, whereas SMC-specific depletion of CXCR4 in the wire-injured mouse femoral arterial wall produced a 60% reduction in IH. Our results provide the first evidence that upregulation of TGFβ/Smad3 in injured arteries induces local SMC CXCR4 expression and cell migration, and consequently IH. The Smad3/CXCR4 pathway may provide a potential target for therapeutic interventions to prevent restenosis. Stem Cells 2016;34:2744-2757.

Topics: Animals; Carotid Arteries; Carotid Artery Injuries; Cell Movement; Gene Expression Regulation; Male; Mice; Mice, Knockout; Microfilament Proteins; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Muscle Proteins; Myocytes, Smooth Muscle; Neointima; Phosphorylation; Primary Cell Culture; Promoter Regions, Genetic; Rats; Rats, Sprague-Dawley; Receptors, CXCR4; Signal Transduction; Smad3 Protein; Transforming Growth Factor beta; Tunica Intima

Neointimal cellular proliferation of fibroblasts and myofibroblasts is documented in coronary artery restenosis, however, their role in peripheral arterial disease (PAD) restenosis remains unclear. Our aim was to investigate the role of fibroblasts, myofibroblasts, and collagens in restenotic PAD.. Nineteen PAD restenotic plaques were compared with 13 de novo plaques. Stellate cells (H&E), fibroblasts (FSP-1), myofibroblasts (α-actin/vimentin/FSP-1), cellular proliferation (Ki-67), and apoptosis (caspase-3 with poly ADP-ribose polymerase) were evaluated by immunofluorescence. Collagens were evaluated by picro-sirius red stain with polarization microscopy. Smooth muscle myosin heavy chain (SMMHC), IL-6 and TGF-β cytokines were analyzed by immunohistochemistry.. Restenotic plaques demonstrated increased stellate cells (2.7 ± 0.15 vs.1.3 ± 0.15) fibroblasts (2282.2 ± 85.9 vs. 906.4 ± 134.5) and myofibroblasts (18.5 ± 1.2 vs.10.6 ± 1.0) p = 0.0001 for all comparisons. In addition, fibroblast proliferation (18.4% ± 1.2 vs.10.4% ± 1.1; p = 0.04) and apoptosis (14.6% ± 1.3 vs.11.2% ± 0.6; p = 0.03) were increased in restenotic plaques. Finally, SMMHC (2.6 ± 0.12 vs.1.4 ± 0.15; p = 0.0001), type III collagen density (0.33 ± 0.06 vs. 0.17 ± 0.07; p = 0.0001), IL-6 (2.08 ± 1.7 vs.1.03 ± 2.0; p = 0.01), and TGF-β (1.80 ± 0.27 vs. 1.11 ± 0.18; p = 0.05) were increased in restenotic plaques.. Our study suggests proliferation and apoptosis of fibroblast and myofibroblast with associated increase in type III collagen may play a role in restenotic plaque progression. Understanding pathways involved in proliferation and apoptosis in neointimal cells, may contribute to future therapeutic interventions for the prevention of restenosis in PAD.

Topics: Actins; Aged; Apoptosis; Arteries; Atherectomy; Caspase 3; Cell Proliferation; Collagen Type III; Constriction, Pathologic; Disease Progression; Extracellular Matrix; Female; Fibroblasts; Humans; Interleukin-6; Male; Middle Aged; Muscle, Smooth; Myofibroblasts; Myosin Heavy Chains; Neointima; Peripheral Arterial Disease; Prevalence; Transforming Growth Factor beta; Vasoconstriction

Smooth muscle cells (SMCs) in normal blood vessels exist in a highly differentiate state characterized by expression of SMC-specific contractile proteins ("contractile phenotype"). Following blood vessel injury in vivo or when cultured in vitro in the presence of multiple growth factors, SMC undergo a phenotype switch characterized by the loss of contractile markers and appearance of expression of non-muscle proteins ("proliferative phenotype"). While a number of factors have been reported to modulate this process, its regulation remains uncertain. Here we show that induction of SMC FGF signaling inhibits TGFβ signaling and converts contractile SMCs to the proliferative phenotype. Conversely, inhibition of SMC FGF signaling induces TGFβ signaling converting proliferating SMCs to the contractile phenotype, even in the presence of various growth factors in vitro or vascular injury in vivo. The importance of this signaling cross-talk is supported by in vivo data that show that an SMC deletion of a pan-FGF receptor adaptor Frs2α (fibroblast growth factor receptor substrate 2 alpha) in mice profoundly reduces neointima formation and vascular remodelling following carotid artery ligation. These results demonstrate that FGF-TGFβ signaling antagonism is the primary regulator of the SMC phenotype switch. Manipulation of this cross-talk may be an effective strategy for treatment of SMC-proliferation related diseases.

Topics: Animals; Bone Morphogenetic Proteins; Carotid Arteries; Cell Differentiation; Cell Proliferation; Disease Models, Animal; Down-Regulation; Fibroblast Growth Factors; Gene Knockout Techniques; Humans; Ligation; Mice; Muscle Contraction; Myocytes, Smooth Muscle; Neointima; Phenotype; Signal Transduction; Transforming Growth Factor beta; Up-Regulation

Mechanisms of restenosis in type 2 diabetes mellitus (T2DM) are incompletely elucidated, but advanced glycation end-product (AGE)-induced vascular remodeling likely contributes. We tested the hypothesis that AGE-related collagen cross-linking (ARCC) leads to increased downstream vascular resistance and altered in-stent hemodynamics, thereby promoting neointimal hyperplasia (NH) in T2DM. We proposed that decreasing ARCC with ALT-711 (Alagebrium) would mitigate this response. Abdominal aortic stents were implanted in Zucker lean (ZL), obese (ZO), and diabetic (ZD) rats. Blood flow, vessel diameter, and wall shear stress (WSS) were calculated after 21 days, and NH was quantified. Arterial segments (aorta, carotid, iliac, femoral, and arterioles) were harvested to detect ARCC and protein expression, including transforming growth factor-β (TGF-β) and receptor for AGEs (RAGE). Downstream resistance was elevated (60%), whereas flow and WSS were significantly decreased (44% and 56%) in ZD vs. ZL rats. NH was increased in ZO but not ZD rats. ALT-711 reduced ARCC and resistance (46%) in ZD rats while decreasing NH and producing similar in-stent WSS across groups. No consistent differences in RAGE or TGF-β expression were observed in arterial segments. ALT-711 modified lectin-type oxidized LDL receptor 1 but not RAGE expression by cells on decellularized matrices. In conclusion, ALT-711 decreased ARCC, increased in-stent flow rate, and reduced NH in ZO and ZD rats through RAGE-independent pathways. The study supports an important role for AGE-induced remodeling within and downstream of stent implantation to promote enhanced NH in T2DM.

Topics: Animals; Aorta, Abdominal; Collagen; Diabetes Mellitus; Glycation End Products, Advanced; Graft Occlusion, Vascular; Male; Neointima; Obesity; Rats; Rats, Zucker; Receptor for Advanced Glycation End Products; Shear Strength; Stents; Stress, Mechanical; Thiazoles; Transforming Growth Factor beta; Vascular Resistance

Smooth muscle cell (SMC) migration and proliferation play an essential role in neointimal formation after vascular injury. In this study, we intended to investigate whether the X-box-binding protein 1 (XBP1) was involved in these processes.. In vivo studies on femoral artery injury models revealed that vascular injury triggered an immediate upregulation of XBP1 expression and splicing in vascular SMCs and that XBP1 deficiency in SMCs significantly abrogated neointimal formation in the injured vessels. In vitro studies indicated that platelet-derived growth factor-BB triggered XBP1 splicing in SMCs via the interaction between platelet-derived growth factor receptor β and the inositol-requiring enzyme 1α. The spliced XBP1 (XBP1s) increased SMC migration via PI3K/Akt activation and proliferation via downregulating calponin h1 (CNN1). XBP1s directed the transcription of mir-1274B that targeted CNN1 mRNA degradation. Proteomic analysis of culture media revealed that XBP1s decreased transforming growth factor (TGF)-β family proteins secretion via transcriptional suppression. TGF-β3 but not TGF-β1 or TGF-β2 attenuated XBP1s-induced CNN1 decrease and SMC proliferation.. This study demonstrates for the first time that XBP1 is crucial for SMC proliferation via modulating the platelet-derived growth factor/TGF-β pathways, leading to neointimal formation.

Topics: Animals; Cell Movement; Cell Proliferation; Cells, Cultured; Disease Models, Animal; DNA-Binding Proteins; Down-Regulation; Femoral Artery; Gene Expression Regulation; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Neointima; Platelet-Derived Growth Factor; Random Allocation; Real-Time Polymerase Chain Reaction; Receptor Cross-Talk; Regulatory Factor X Transcription Factors; RNA, Messenger; Signal Transduction; Transcription Factors; Transforming Growth Factor beta; Vascular Remodeling; Vascular System Injuries; X-Box Binding Protein 1

The endoplasmic reticulum (ER) stress protein, calreticulin (CRT), is required for the production of TGF-β-stimulated extracellular matrix (ECM) by fibroblasts. Since TGF-β regulates vascular fibroproliferative responses and collagen deposition, we investigated the effects of CRT knockdown on vascular smooth-muscle cell (VSMC) fibroproliferative responses and collagen deposition.. Using a carotid artery ligation model of vascular injury, Cre-recombinase-IRES-GFP plasmid was delivered with microbubbles (MB) to CRT-floxed mice using ultrasound (US) to specifically reduce CRT expression in the carotid artery.. In vitro, Cre-recombinase-mediated CRT knockdown in isolated, floxed VSMCs decreased the CRT transcript and protein, and attenuated the induction of collagen I protein in response to TGF-β. TGF-β stimulation of collagen I was partly blocked by the NFAT inhibitor 11R-VIVIT. Following carotid artery ligation, CRT staining was upregulated with enhanced expression in the neointima 14-21 days after injury. Furthermore, Cre-recombinase-IRES-GFP plasmid delivered by targeted US reduced CRT expression in the neointima of CRT-floxed mice and led to a significant reduction in neointima formation and collagen deposition. The neointimal cell number was also reduced in mice, with a local, tissue-specific knockdown of CRT.. This work establishes a novel role for CRT in mediating VSMC responses to injury through the regulation of collagen deposition and neointima formation.

Topics: Animals; Calbindin 2; Carotid Arteries; Carotid Artery Injuries; Cell Proliferation; Cells, Cultured; Collagen Type I; Collagen Type I, alpha 1 Chain; Disease Models, Animal; Ligation; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; Signal Transduction; Time Factors; Transfection; Transforming Growth Factor beta; Up-Regulation

Hemodialysis as an efficient therapy for advanced CKD is the most used treatment modality all over the world. Even though primary AVF is widely accepted as a best permanent vascular access in hemodialysis patients, up to 60% of all fistulas fail to mature. The pathogenesis of early fistula failure is not very well understood. Many general and local factors are involved: patient's age, sex, primary renal disease, small vessel's diameter, presence of accessory veins, prior venipunctures, surgical skill, genetics, etc. Histological investigations have confirmed the neointimal venous hyperplasia as a major pathological finding in stenotic lesions of AVF failure, due to local inflammation, oxidative stress and migration and proliferation of myofibroblasts, fibroblasts and endothelial cells.. A total of 89 patients with stadium 4-5 of CKD are involved in the study. A typical radio-cephalic AVF is created in all patients. Part of the fistula vein was taken for histological, immunohistochemical (Vimentin, TGF β and KI67) and morphometric analysis. Appriopriate statistical method was applied.. Up to 80% of the patients showed some degree of endothelial changes at the time of creation of AVF, among them 19 pts with substantial intimal hyperplasia, 51 with medial hypertrophy and 19 pts with normal histology. Almost two thirds of the patients did not have expression of TGFβ. More than 95% had some expression of Vimentin. None of the patients had expression of the marker KI 67.. Medial hypertrophy is predominant preexisting pathohistological lesion prior the AVF creation, despite the presence of neointimal hyperplasia. The absence of TGFβ expression in majority of our patients could suggest that inflammation and oxidative stress are developing later, after vascular access surgery. The dominant cells within the stenosis in the veins are myofibroblasts. Their increased presence maybe a reason why some patients are prone to developing venous endothelial changes as a results of exaggerated vascular endothelial response to the effect of uremia, hypertension and other insults.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Arteriovenous Shunt, Surgical; Biomarkers; Endothelial Cells; Female; Graft Occlusion, Vascular; Humans; Hyperplasia; Hypertrophy; Immunohistochemistry; Ki-67 Antigen; Male; Middle Aged; Neointima; Prospective Studies; Radial Artery; Renal Dialysis; Renal Insufficiency, Chronic; Risk Factors; Severity of Illness Index; Transforming Growth Factor beta; Treatment Failure; Veins; Vimentin; Young Adult

Vascular calcification is an actively regulated process that culminates in organized extracellular matrix mineral deposition by osteoblast-like cells. The origins of the osteoblastic cells involved in this process and the underlying mechanisms remain to be defined. We previously revealed that active transforming growth factor (TGFβ) released from the injured arteries mobilizes mesenchymal stem cells (MSCs) to the blood stream and recruits the cells to the injured vessels for neointima formation. In this study, we used a low-density lipoprotein receptor (LDLR)-deficient mouse model (ldlr(-/-)), which develop progressive arterial calcification after having fed high-fat western diets (HFD), to examine whether TGFβ is involved in the mobilization of MSCs during vascular calcification. Nestin(+)/Sca1(+) cells were recruited to the diseased aorta at earlier time points, and osteocalcin(+) osteoblasts and the aortic calcification were seen at later time point in these mice. Importantly, we generated parabiotic pairs with shared blood circulation by crossing ldlr(-/-)mice fed HFD with transgenic mice, in which all the MSC-derived cells were fluorescently labeled. The labeled cells were detected not only in the peripheral blood but also in the arterial lesions in ldlr(-/-) mouse partners, and these blood circulation-originated cells gave rise to Ocn(+) osteoblastic cells at the arterial lesions. Both active TGFβ1 levels and MSCs in circulating blood were upregulated at the same time points when these cells appeared at the aortic tissue. Further, conditioned medium prepared by incubating the aortae from ldlr(-/-)mice fed HFD stimulated the migration of MSCs in the ex vivo transwell assays, and either TGFβ neutralizing antibody or the inhibitor of TGFβ Receptor I kinase (TβRI) antagonized this effect. Importantly, treatment of the mice with TβRI inhibitor blocked elevated blood MSC numbers and their recruitment to the arterial lesions. These findings suggest that TGFβ-recruited MSCs to the diseased vasculature contribute to the development of osteogenic vascular calcification.

Topics: Animals; Aorta; Cell Differentiation; Extracellular Matrix; Mesenchymal Stem Cells; Mice; Neointima; Osteoblasts; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type I; Receptors, LDL; Receptors, Transforming Growth Factor beta; Transforming Growth Factor beta; Transforming Growth Factor beta1; Vascular Calcification

To define the contribution of vascular smooth muscle cell (SMC)-derived factors to macrophage phenotypic modulation in the setting of vascular injury.. By flow cytometry, macrophages (M4) were the predominant myeloid cell type recruited to wire-injured femoral arteries, in mouse, compared with neutrophils or eosinophils. Recruited macrophages from injured vessels exhibited a distinct expression profile relative to circulating mononuclear cells (peripheral blood monocytes; increased: interleukin-6, interleukin-10, interleukin-12b, CC chemokine receptor [CCR]3, CCR7, tumor necrosis factor-α, inducible nitric oxide synthase, arginase 1; decreased: interleukin-12a, matrix metalloproteinase [MMP]9). This phenotype was recapitulated in vitro by maturing rat bone marrow cells in the presence of macrophage-colony stimulating factor and 20% conditioned media from cultured rat SMC (sMϕ) compared with maturation in macrophage-colony stimulating factor alone (M0). Recombinant transforming growth factor (TGF)-β1 recapitulated the effect of SMC conditioned media. Macrophage maturation studies performed in the presence of a pan-TGF-β neutralizing antibody, a TGF-β receptor inhibitor, or conditioned media from TGF-β-depleted SMCs confirmed that the SMC-derived factor responsible for macrophage activation was TGF-β. Finally, the effect of SMC-mediated macrophage activation on SMC biology was assessed. SMCs cocultured with sMϕ exhibited increased rates of proliferation relative to SMCs cultured alone or with M0 macrophages.. SMC-derived TGF-β modulates the phenotype of maturing macrophages in vitro, recapitulating the phenotype found in vascular lesions in vivo. SMC-modulated macrophages induce SMC activation to a greater extent than control macrophages.

Topics: Animals; Biomarkers; Cell Proliferation; Cells, Cultured; Coculture Techniques; Culture Media, Conditioned; Cytokines; Disease Models, Animal; Femoral Artery; Humans; Macrophage Activation; Macrophage Colony-Stimulating Factor; Macrophages; Mice; Mice, Inbred C57BL; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; p38 Mitogen-Activated Protein Kinases; Paracrine Communication; Phenotype; Rats; RNA Interference; Time Factors; Transfection; Transforming Growth Factor beta; Transforming Growth Factor beta1; Vascular System Injuries

Veins grafted into an arterial environment undergo a complex vascular remodeling process. Pathologic vascular remodeling often results in stenosed or occluded conduit grafts. Understanding this complex process is important for improving the outcome of patients with coronary and peripheral artery disease undergoing surgical revascularization. Using in vivo murine cell lineage-tracing models, we show that endothelial-derived cells contribute to neointimal formation through endothelial-to-mesenchymal transition (EndMT), which is dependent on early activation of the Smad2/3-Slug signaling pathway. Antagonism of transforming growth factor-β (TGF-β) signaling by TGF-β neutralizing antibody, short hairpin RNA-mediated Smad3 or Smad2 knockdown, Smad3 haploinsufficiency, or endothelial cell-specific Smad2 deletion resulted in decreased EndMT and less neointimal formation compared to controls. Histological examination of postmortem human vein graft tissue corroborated the changes observed in our mouse vein graft model, suggesting that EndMT is operative during human vein graft remodeling. These data establish that EndMT is an important mechanism underlying neointimal formation in interpositional vein grafts, and identifies the TGF-β-Smad2/3-Slug signaling pathway as a potential therapeutic target to prevent clinical vein graft stenosis.

Topics: Animals; Antibodies, Neutralizing; Cell Lineage; Cell Transdifferentiation; Endothelial Cells; Gene Knockdown Techniques; Humans; Mesoderm; Mice; Neointima; Signal Transduction; Smad2 Protein; Smad3 Protein; Snail Family Transcription Factors; Transcription Factors; Transforming Growth Factor beta; Veins

In the present study, we aimed to deterimine the dose-related effects of ticagrelor, the first reversible inhibitor of the P2Y12 receptor, found in smooth muscle cells as well as platelets, during neointimal hyperplasia in a rabbit carotid anastomosis model.. This study was an experimental, prospective, randomized controlled study including 20 New Zealand white female rabbits (6-months old; weighing 2300 ± 300 g). Under general anaesthesia, the rabbits underwent transection of the right carotid artery and subsequent anastomosis of both ends. The study animals were divided into the following 4 groups: T1 (ticagrelor 5 mg/kg, orally, daily), T2 (ticagrelor 10 mg/kg, orally, daily), T3 (ticagrelor 20 mg/kg, orally, daily) and control (no ticagrelor treatment). The single oral doses were administered in phosphate-buffered saline. The control group received sterile phosphate-buffered saline (2 ml/kg/day, orally) for 3 weeks postoperatively. At the end of the study, the animals were killed, and the anastomosed segment of the right carotid artery and part of the left carotid artery were excised from each animal. Antibodies against transforming growth factor-β were used in staining of arterial sections, which was followed by histomorphological and immunohistochemical studies.. The median intimal thickness (2.0 ± 0.14 µm left vs 73.4 ± 35.8 µm anastomosed right arteries; P <0.05), the median medial thickness (70.8 ± 5.6 µm left vs 92.3 ± 4.5 µm anastomosed right arteries; P <0.05) and the index ratio of intimal thickness to medial thickness (0.03 ± 0.00 left vs 0.8 ± 0.35 anastomosed control right arteries; P <0.05) increased significantly in the anastomosed right arteries compared with the left carotid arteries in the control group. In the treatment groups, the intimal thickness (73.4 ± 35.8 µm in control group vs T1 32.7 ± 19;1 µm, T2 1.9 ± 0.09 µm and T3 2.2 ± 0.5 µm; P = 0.047, P = 0.009 and P = 0.009, respectively), carotid artery intima/media ratio (0.8 ± 0.35 in control group vs T1 0.4 ± 0.2, T2 0.03 ± 0.01 and T3 0.03 ± 0.01 in ticagrelor groups; P = 0.028, P = 0.009 and P = 0.009, respectively) and medial thickness (92.3 ± 4.5 µm in control group vs T2 65.6 ± 7.1 and T3 66.1 ± 7.6 µm; P = 0.009 and P = 0.009, respectively) decreased significantly in the anastomosed right arteries.. This study indicates that effective doses (10 and 20 mg/kg, daily) of the antiplatelet agent ticagrelor in a rabbit model may be beneficial in prevention of intimal hyperplasia. Restenosis due to intimal hyperplasia has been high. Ticagrelor has also been linked to inhibition of smooth muscle cell proliferation and, hence, reduced intimal hyperplasia.

Topics: Adenosine; Anastomosis, Surgical; Animals; Biopsy; Carotid Arteries; Carotid Stenosis; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Hyperplasia; Immunohistochemistry; Neointima; Platelet Aggregation Inhibitors; Purinergic P2Y Receptor Antagonists; Rabbits; Receptors, Purinergic P2Y12; Recurrence; Ticagrelor; Transforming Growth Factor beta

Neointima formation following angioplasty is a serious consequence of endothelial damage in arteries. Inflammatory mediators and lack of endothelial regulatory mechanisms lead to migration and proliferation of smooth-muscle cells and thus to restenosis. This study examines the effect of the novel bis (aspirinato) zinc (II) complex on neointima formation in a rat model of carotid balloon-injury.. Rats underwent balloon-injury of the right common carotid artery, then received PEG400 vehicle (untreated-group), acetylsalicylic-acid (ASA-group), zinc-chloride (Zn-group) and bis (aspirinato) zinc (II) complex (Zn(ASA) 2-group) orally for 18 consecutive days. From harvested carotid arteries, histology, immunohistochemistry and mRNA expression analysis were performed.. Compared to the untreated-group, Zn (ASA) 2-treatment significantly lowered stenosis ratio (54.0 ± 5.8% to 25.5 ± 3.9%) and reduced neointima/media ratio (1.5 ± 0.2 to 0.5 ± 0.1). Significantly higher alpha smooth muscle actin mRNA and protein expression were measured after Zn (ASA)2 and Zn-treatment in comparison with the untreated and ASA-groups while the expression of matrix-metalloproteinase-9 was significantly higher in these groups compared to Zn (ASA)2. The presence of collagen in media was significantly decreased in all treated groups. mRNA expressions of nuclear factor kappa-b, transforming growth-factor-β and proliferating cell nuclear antigen were significantly down-regulated, whereas a20 was up-regulated by Zn (ASA)2 treatment compared to the untreated and ASA-groups.. This study proves the effectivity of the novel bis (aspirinato) zinc complex in reducing neointima formation and restenosis after balloon-injury and supports the hypothesis that inhibition of smooth-muscle transformation/proliferation plays a key role in the prevention of restenosis.

Topics: Animals; Carotid Arteries; Carotid Artery Injuries; Collagen; Down-Regulation; Male; Matrix Metalloproteinase 9; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Neointima; NF-kappa B; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transforming Growth Factor beta; Zinc

Abnormal vascular homeostasis can lead to increased proliferation of smooth muscle cells and deposition of extracellular matrix, resulting in neointima formation, which contributes to vascular lumen narrowing, a pathology that underlies diseases including transplant vasculopathy, the recurrence of stenosis, and atherosclerosis. Growth of neointima is in part due to endothelial-to-mesenchymal transition (EndMT), a transforming growth factor-β (TGFβ)-driven process, which leads to increased numbers of smooth muscle cells and fibroblasts and deposition of extracellular matrix. We reported that endothelial cell-specific knockout of fibroblast growth factor receptor 1 (FGFR1) led to activation of TGFβ signaling and development of EndMT in vitro and in vivo. Furthermore, EndMT in human diseased vasculature correlated with decreased abundance of FGFR1. These findings identify FGFR1 as the key regulator of TGFβ signaling and EndMT development.

Topics: Animals; Cell Transdifferentiation; Coronary Vessels; Endothelium, Vascular; Extracellular Matrix; Fibroblasts; Graft Rejection; Heart Transplantation; Heterografts; Hindlimb; Human Umbilical Vein Endothelial Cells; Humans; Ischemia; Mesoderm; Mice; Mice, Mutant Strains; MicroRNAs; Muscle, Smooth, Vascular; Neointima; Receptor, Fibroblast Growth Factor, Type 1; Receptors, Fibroblast Growth Factor; Signal Transduction; Smad2 Protein; Transforming Growth Factor beta; Transplantation Chimera

Maintenance of normal endothelial function is critical to various aspects of blood vessel function, but its regulation is poorly understood. In this study, we show that disruption of baseline fibroblast growth factor (FGF) signaling to the endothelium leads to a dramatic reduction in let-7 miRNA levels that, in turn, increases expression of transforming growth factor (TGF)-β ligands and receptors and activation of TGF-β signaling, leading to endothelial-to-mesenchymal transition (Endo-MT). We also find that Endo-MT is an important driver of neointima formation in a murine transplant arteriopathy model and in rejection of human transplant lesions. The decline in endothelial FGF signaling input is due to the appearance of an FGF resistance state that is characterized by inflammation-dependent reduction in expression and activation of key components of the FGF signaling cascade. These results establish FGF signaling as a critical factor in maintenance of endothelial homeostasis and point to an unexpected role of Endo-MT in vascular pathology.

Topics: Animals; Disease Models, Animal; Endothelium; Fibroblast Growth Factors; Gene Expression Regulation; Humans; Mice; Mice, Inbred BALB C; Mice, Transgenic; MicroRNAs; Neointima; Signal Transduction; Transforming Growth Factor beta; Vasculitis

Extracellular matrix (ECM) accumulation significantly contributes to in-stent restenosis. In this regard, transforming growth factor (TGF)-β, a positive regulator of ECM deposition, may be implicated in in-stent restenosis. The goal of this study was to assess the effect of blockade of TGF-β on stent-induced restenosis in porcine coronary arteries.. An adenovirus expressing the ectodomain of the TGF-β type II receptor (AdTβ-ExR) was applied onto a coronary arterial segment of a pig (n=10) using an Infiltrator, followed by stent deployment. Controls consisted of adenoviruses expressing β-galactosidase (AdLacZ) or phosphate-buffered saline (PBS) applied onto the other segment (n=10) of the same pig.. Computer-based pathological morphometric analysis of stented coronary arteries, performed 4 weeks after stenting, demonstrated no significant difference in morphometric parameters such as in-stent neointimal area and % area stenosis between the AdTβ-ExR group and control (n=7 for each). However the AdTβ-ExR group had increased neointimal cell density, infiltration of inflammatory cells mostly consisting of CD3+ T cell, accumulation of hyaluronan, cell proliferation rate, and adventitial matrix metalloproteinase-1 (MMP-1) expression compared with control. The expression of connective tissue growth factor mRNA, measured by reverse transcription PCR, in cultured rat arterial smooth muscle cells was inhibited by AdTβ-ExR at moi 60.. Blockade of TGF-β by catheter-based local intravascular gene delivery does not reduce stent-induced neointima formation 4 weeks after stenting in spite of modest inhibition of ECM accumulation, but it induces vascular inflammation and associated pathological changes that may potentially aggravate lesion progression.

Topics: Angioplasty; Animals; Catheterization; CD3 Complex; Cells, Cultured; Connective Tissue Growth Factor; Coronary Artery Disease; Female; Gene Transfer Techniques; Hyaluronic Acid; In Vitro Techniques; Male; Matrix Metalloproteinase 1; Muscle, Smooth, Vascular; Neointima; Protein Serine-Threonine Kinases; Rats; Rats, Sprague-Dawley; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Stents; Swine; T-Lymphocytes; Transforming Growth Factor beta