RESUMO
Perlecan is a proteoglycan composed of a 470-kDa core protein linked to three heparan sulfate (HS) glycosaminoglycan chains. The intact proteoglycan inhibits the smooth muscle cell (SMC) response to vascular injury. Hspg2(Δ3/Δ3) (MΔ3/Δ3) mice produce a mutant perlecan lacking the HS side chains. The objective of this study was to determine differences between these two types of perlecan in modifying SMC activities to the arterial injury response, in order to define the specific role of the HS side chains. In vitro proliferative and migratory activities were compared in SMC isolated from MΔ3/Δ3 and wild-type mice. Proliferation of MΔ3/Δ3 SMC was 1.5× greater than in wild type (P < 0.001), increased by addition of growth factors, and showed a 42% greater migratory response than wild-type cells to PDGF-BB (P < 0.001). In MΔ3/Δ3 SMC adhesion to fibronectin, and collagen types I and IV was significantly greater than wild type. Addition of DRL-12582, an inducer of perlecan expression, decreased proliferation and migratory response to PDGF-BB stimulation in wild-type SMC compared with MΔ3/Δ3. In an in vivo carotid artery wire injury model, the medial thickness, medial area/lumen ratio, and macrophage infiltration were significantly increased in the MΔ3/Δ3 mice, indicating a prominent role of the HS side chain in limiting vascular injury response. Mutant perlecan that lacks HS side chains had a marked reduction in the inhibition of in vitro SMC function and the in vivo arterial response to injury, indicating the critical role of HS side chains in perlecan function in the vessel wall.
Assuntos
Lesões das Artérias Carótidas/metabolismo , Proteoglicanas de Heparan Sulfato/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Remodelação Vascular , Lesões do Sistema Vascular/metabolismo , Animais , Becaplermina , Artérias Carótidas/metabolismo , Artérias Carótidas/patologia , Lesões das Artérias Carótidas/genética , Lesões das Artérias Carótidas/patologia , Adesão Celular , Movimento Celular , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Fator 2 de Crescimento de Fibroblastos/farmacologia , Genótipo , Proteoglicanas de Heparan Sulfato/química , Proteoglicanas de Heparan Sulfato/genética , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Camundongos Transgênicos , Estrutura Molecular , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/lesões , Músculo Liso Vascular/patologia , Mutação , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/patologia , Fenótipo , Proteínas Proto-Oncogênicas c-sis/farmacologia , Relação Estrutura-Atividade , Fatores de Tempo , Remodelação Vascular/efeitos dos fármacos , Lesões do Sistema Vascular/genética , Lesões do Sistema Vascular/patologiaRESUMO
AIMS: Percutaneous revascularisation of chronic total occlusions (CTO) is limited by failure of guidewire crossing. Neovascularisation within the proximal CTO segment may be important for guidewire crossing and dramatically declines in CTO beyond six weeks of age. The aims of the current study were to determine whether local delivery of a pro-angiogenic growth factor increases neovascularisation in mature CTO and facilitates guidewire crossings. METHODS AND RESULTS: CTO (n=51) were created in the femoral arteries of 44 New Zealand white rabbits using the thrombin injection model. At 12 weeks, CTO were treated with poly-lactic-glycolic-acid (PLGA) microspheres containing either bovine serum albumin (BSA) (n=15) or recombinant mouse VEGF164 (n=14), or received no intervention (controls, n=12). Contrast-enhanced magnetic resonance angiography (CEMRA) was performed prior to treatment and at three weeks post treatment. Animals were sacrificed at three weeks post treatment and arterial samples were excised for micro-computed tomography imaging (µCT) and histologic morphometric analysis. Guidewire crossing was assessed at three weeks post treatment in an additional 10 VEGF164-treated CTO. In comparison to BSA-treated and control non-intervened CTO, VEGF164-treated CTO showed a significant increase in relative blood volume index in the proximal segment of the CTO lesion as determined by CEMRA and by µCT. Histologic measurements of microvessel area were also higher in VEGF164-treated CTO. Guidewire crossing across the proximal fibrous cap was successful in eight out of 10 VEGF164-treated CTO. CONCLUSIONS: Angiogenic therapy appears to be a promising strategy to improve neovascularisation and guidewire crossing rates in CTO.
Assuntos
Indutores da Angiogênese/uso terapêutico , Arteriopatias Oclusivas/cirurgia , Procedimentos Endovasculares/instrumentação , Procedimentos Endovasculares/métodos , Artéria Femoral , Fator A de Crescimento do Endotélio Vascular/uso terapêutico , Indutores da Angiogênese/administração & dosagem , Indutores da Angiogênese/farmacologia , Animais , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Doença Crônica , Modelos Animais de Doenças , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Técnicas In Vitro , Injeções Intra-Arteriais , Masculino , Camundongos , Microesferas , Microvasos/citologia , Microvasos/efeitos dos fármacos , Coelhos , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/uso terapêutico , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/administração & dosagem , Fator A de Crescimento do Endotélio Vascular/farmacologiaRESUMO
Four drug-eluting stents were deployed in the right coronary artery (RCA) of a symptomatic young woman who presented with a chronic total occlusion (CTO) of the RCA. The occlusion was successfully crossed using the recently described STAR technique. However, the patient died suddenly 15 hr later. Autopsy demonstrated a long segment of subintimal stenting in the proximal and mid RCA that was intraluminal in the distal vessel. Acute stent thrombosis in the subintimal stents was responsible for sudden death. This case highlights the potential risk of performing extensive subintimal stenting for CTO.