RESUMO
Peroxisome proliferator-activated receptor x03B3; agonists have been shown to inhibit angiotensin II (AngII)-induced experimental abdominal aortic aneurysms. Macrophage infiltration to the vascular wall is an early event in this pathology, and therefore we explored the effects of the peroxisome proliferator-activated receptor x03B3; agonist pioglitazone on AngII-treated macrophages. Using microarray-based expression profiling of phorbol ester-stimulated THP-1 cells, we found that a number of aneurysm-related gene changes effected by AngII were modulated following the addition of pioglitazone. Among those genes, polycystic kidney disease 1 (PKD1) was significantly up-regulated (multiple testing corrected p < 0.05). The analysis of the PKD1 proximal promoter revealed a putative early growth response 1 (EGR1) binding site, which was confirmed by chromatin immunoprecipitation (ChIP) and quantitative PCR. Further analysis of publicly available ChIP-sequencing data revealed that this putative binding site overlapped with a conserved EGR1 binding peak present in 5 other cell lines. Quantitative real-time PCR showed that EGR1 suppressed PKD1, while AngII significantly up-regulated PKD1, an effect counteracted by pioglitazone. Conversely, in EGR1 short hairpin RNA lentivirally transduced THP-1 cells, reduced EGR1 led to a significant up-regulation of PKD1, especially after treatment with pioglitazone. In vivo, deficiency of Egr1 in the haematopoietic compartment of mice completely abolished the incidence of CaCl2-induced aneurysm formation.
Assuntos
Aneurisma da Aorta Abdominal/prevenção & controle , Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Macrófagos/efeitos dos fármacos , Tiazolidinedionas/farmacologia , Angiotensina II/farmacologia , Animais , Aneurisma da Aorta Abdominal/induzido quimicamente , Aneurisma da Aorta Abdominal/genética , Aneurisma da Aorta Abdominal/metabolismo , Sequência de Bases , Sítios de Ligação , Cloreto de Cálcio , Linhagem Celular Tumoral , Modelos Animais de Doenças , Proteína 1 de Resposta de Crescimento Precoce/deficiência , Proteína 1 de Resposta de Crescimento Precoce/genética , Feminino , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Humanos , Macrófagos/metabolismo , Masculino , Camundongos Knockout , Dados de Sequência Molecular , PPAR gama/agonistas , PPAR gama/metabolismo , Pioglitazona , Regiões Promotoras Genéticas , Interferência de RNA , Transdução de Sinais/efeitos dos fármacos , Canais de Cátion TRPP/genética , Canais de Cátion TRPP/metabolismo , Fatores de Tempo , TransfecçãoRESUMO
BACKGROUND: Elevation of plasma high-density lipoprotein (HDL) cholesterol concentration reduces cardiovascular mortality and morbidity. HDLs have been shown to possess acute anti-inflammatory, antioxidant, and antithrombotic properties. We hypothesize that HDL therapy can acutely alter local and systemic manifestations of plaque instability. METHODS: Forty patients with early symptomatic carotid disease were randomized to either receive reconstituted HDL (rHDL) 40 mg/kg (n = 20) or placebo (n = 20). Carotid endarterectomies were performed 24 hr later. Plaques were obtained intraoperatively and used for measurement of thrombomodulatory genes expression. Plasma samples were collected before the infusion, 24 and 48 hr later to measure changes in systemic markers of plaque instability. RESULTS: No significant differences were noted in thrombomodulatory genes expression between the 2 groups. Systemic levels of tissue factor, matrix metalloproteinase 9 (MMP-9), and monocyte chemotactic factor-1 (MCP-1) were significantly reduced in the rHDL group. However, the effects on MMP-9 and MCP-1 were abolished in the immediate postoperative period. Although rHDL did not affect plasma interleukin-6 levels 24 hr following the infusion, it prevented the significant postoperative elevation seen in the placebo group. CONCLUSIONS: A single infusion of rHDL can acutely alter plasma biomarkers associated with plaque instability and cardiovascular morbidity.
Assuntos
Artéria Carótida Interna/cirurgia , Estenose das Carótidas/terapia , Endarterectomia das Carótidas , Lipoproteínas HDL/administração & dosagem , Placa Aterosclerótica , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Artéria Carótida Interna/metabolismo , Artéria Carótida Interna/patologia , Estenose das Carótidas/sangue , Estenose das Carótidas/complicações , Estenose das Carótidas/diagnóstico , Estenose das Carótidas/genética , Feminino , Regulação da Expressão Gênica , Humanos , Mediadores da Inflamação/sangue , Infusões Intravenosas , Lipoproteínas HDL/sangue , Londres , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do TratamentoRESUMO
OBJECTIVE: Patients with abdominal aortic aneurysms have lower concentrations of high-density lipoproteins (HDLs), leading us to investigate whether increasing plasma HDLs could influence aneurysm formation. METHODS AND RESULTS: Using the angiotensin II-induced hypercholesterolemic and the CaCl(2)-induced normocholesterolemic mouse model of AAA, we investigated the hypothesis that elevation of HDLs inhibits AAA. HDLs elevated before or at the time of AAA induction reduced AAA formation in both models but had no effect on early ruptures. Analysis of protein lysates from specific aortic segments demonstrated site-specific effects of HDLs on early signal transduction and cellular attrition. We found that HDLs reduced extracellular signal related kinases 1/2 activation in the suprarenal segment, while having no effect on p38 mitogen-associated protein kinase activation in any aortic segment and inhibiting c-Jun N-terminal kinase activation in all aortic segments. In addition, HDL elevation inhibited angiotensin II-induced apoptosis while inducing autophagy in the suprarenal segment of the aorta. Using Illumina gene array profiling we investigated the ability of HDL to modulate basal suprarenal aortic gene expression. CONCLUSIONS: Increasing plasma HDLs inhibit experimental AAA formation, independent of hypercholesterolemia via reduced extracellular signal related kinases 1/2 activation and alteration of the balance of cellular attrition. HDLs modulate genes involved in matrix remodelling, cell migration, and proliferation.
Assuntos
Aneurisma da Aorta Abdominal/prevenção & controle , Lipoproteínas HDL/sangue , Angiotensina II , Animais , Aorta/metabolismo , Aorta/patologia , Aneurisma da Aorta Abdominal/sangue , Aneurisma da Aorta Abdominal/etiologia , Aneurisma da Aorta Abdominal/genética , Aneurisma da Aorta Abdominal/patologia , Ruptura Aórtica/sangue , Ruptura Aórtica/etiologia , Ruptura Aórtica/prevenção & controle , Apolipoproteínas E/deficiência , Apolipoproteínas E/genética , Autofagia , Cloreto de Cálcio , Modelos Animais de Doenças , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Hipercolesterolemia/complicações , Hipercolesterolemia/genética , Injeções Subcutâneas , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Lipoproteínas HDL/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Transdução de Sinais , Fatores de Tempo , Regulação para Cima , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Homeostasis of the vessel wall is essential for maintaining its function, including blood pressure and patency of the lumen. In physiological conditions, the turnover rate of vascular cells, i.e. endothelial and smooth muscle cells, is low, but markedly increased in diseased situations, e.g. vascular injury after angioplasty. It is believed that mature vascular cells have an ability to proliferate to replace lost cells normally. On the other hand, recent evidence indicates stem/progenitor cells may participate in vascular repair and the formation of neointimal lesions in severely damaged vessels. It was found that all three layers of the vessels, the intima, media and adventitia, contain resident progenitor cells, including endothelial progenitor cells, mesenchymal stromal cells, Sca-1+ and CD34+ cells. Data also demonstrated that these resident progenitor cells could differentiate into a variety of cell types in response to different culture conditions. However, collective data were obtained mostly from in vitro culture assays and phenotypic marker studies. There are many unanswered questions concerning the mechanism of cell differentiation and the functional role of these cells in vascular repair and the pathogenesis of vascular disease. In the present review, we aim to summarize the data showing the presence of the resident progenitor cells, to highlight possible signal pathways orchestrating cell differentiation toward endothelial and smooth muscle cells, and to discuss the data limitations, challenges and controversial issues related to the role of progenitors. This article is part of a special issue entitled, "Cardiovascular Stem Cells Revisited".
Assuntos
Diferenciação Celular , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Células-Tronco/citologia , Células-Tronco/metabolismo , Animais , Células Endoteliais/patologia , Homeostase/fisiologia , Humanos , Mioblastos de Músculo Liso/citologia , Mioblastos de Músculo Liso/metabolismo , Pericitos/citologia , Pericitos/metabolismo , Células-Tronco/patologia , Doenças Vasculares/patologia , Doenças Vasculares/fisiopatologiaRESUMO
INTRODUCTION: Abdominal aortic aneurysms (AAA) are associated with inflammation, apoptosis, and matrix degradation. AAA tissue represents the end stage of disease, limiting its utility in identification of factors culpable for initiation of aneurysm development. Recent evidence suggests that AAAs are a local representation of a systemic disease of the vasculature. Morphologic and molecular changes, comparable to those found in the aneurysm wall, have been demonstrated in veins from patients with AAAs. Changes in the vascular tissue proteome of patients with AAAs were investigated, using inferior mesenteric vein (IMV), to gain insight into early molecular changes contributing to AAA development. METHODS: IMV was harvested from 16 patients with AAA and 16 matched controls. Whole IMV lysates were subjected to 2-D difference in gel electrophoresis (2D-DIGE) with quantitative densitometry. Protein spots differentially expressed in AAA were identified using mass spectrometry. Differential protein expression was validated by Western blotting and localized to cell type by immunohistochemistry (IHC). RESULTS: Decreased levels of prohibitin (AAA, 2.00 ± 1.37; controls, 3.81 ± 1.39; 1.9-fold change; P = .02) AAA (7.33 ± 3.9; controls, 14.5 ± 5.6; 2-fold change; P = .001), along with relative increases in a cleaved fragment of vimentin (AAA, 12.9 ± 9; controls, 6.9 ± 4.7; 2-fold change; P = .11) were identified in AAA patients. All proteins were localized to the vascular smooth muscle cells. CONCLUSIONS: Proteins important in combating the injurious effects of oxidative stress and modulating the response to inflammation appear reduced in the vasculature of patients with AAA. These changes may represent early events in AAA formation. Enhancing expression of these proteins might offer a novel therapeutic avenue to inhibit AAA development.
Assuntos
Aneurisma da Aorta Abdominal/metabolismo , Músculo Liso Vascular/química , Miócitos de Músculo Liso/química , Proteínas/análise , Proteômica , Idoso , Anexina A1/análise , Aorta Abdominal/química , Western Blotting , Estudos de Casos e Controles , Densitometria , Eletroforese em Gel Bidimensional , Feminino , Humanos , Imuno-Histoquímica , Londres , Masculino , Espectrometria de Massas , Veias Mesentéricas/química , Pessoa de Meia-Idade , Proibitinas , Proteômica/métodos , Proteínas Repressoras/análise , Reprodutibilidade dos Testes , Vimentina/análiseRESUMO
BACKGROUND: Development and rupture of aortic aneurysms involve a combination of complex biological processes. Rosiglitazone, a peroxisome proliferator-activated receptor-gamma agonist, has been shown to have a broad spectrum of effects in vivo. The hypothesis that rosiglitazone would reduce aneurysm expansion or rupture was tested in the angiotensin II (Ang II)-induced hypercholesterolemic mouse model. METHODS AND RESULTS: Apolipoprotein E-deficient mice, 12 months of age, were allocated to 4 groups. Three groups were infused with Ang II (1 microg . min(-1) . kg(-1)), and the fourth was infused with saline. Rosiglitazone was given 1 week before infusion and 1 week after infusion. At day 28, aortic size was measured, and tissues were collected for analyses. Both pretreatment and posttreatment with rosiglitazone inhibited the occurrence of fatal rupture (11 of 30 versus 0 of 30 versus 0 of 15; P=0.0013) and reduced maximal dilatation of the aorta (4.6+/-0.13 versus 2.4+/-0.48 versus 2.15+/-0.46 mm2; P<0.0001). Blood glucose, total cholesterol, body weight, and atherosclerosis did not differ between groups. Pretreatment with rosiglitazone inhibited the Ang II-induced expression of angiotensin type 1a Ang II receptor while having no effect on the angiotensin type 2 Ang II receptor, in addition to reducing Ang II-induced expression of E-selectin, tumor necrosis factor-alpha, and interleukin-6. CONCLUSIONS: Pretreatment or posttreatment with RGZ reduced aortic expansion and rupture in this mouse model. Reduction of lesions in animals pretreated with rosiglitazone is concomitant with decreased expression of inflammatory mediators. Further studies are needed to elucidate the precise mechanism.
Assuntos
Aneurisma da Aorta Abdominal/prevenção & controle , Ruptura Aórtica/prevenção & controle , Hipoglicemiantes/farmacologia , Tiazolidinedionas/farmacologia , Angiotensina II/efeitos adversos , Angiotensina II/farmacologia , Animais , Aneurisma da Aorta Abdominal/sangue , Aneurisma da Aorta Abdominal/induzido quimicamente , Aneurisma da Aorta Abdominal/genética , Aneurisma da Aorta Abdominal/patologia , Ruptura Aórtica/sangue , Ruptura Aórtica/induzido quimicamente , Ruptura Aórtica/genética , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Glicemia/análise , Peso Corporal/efeitos dos fármacos , Colesterol/sangue , Modelos Animais de Doenças , Selectina E/sangue , Humanos , Hipercolesterolemia/sangue , Hipercolesterolemia/induzido quimicamente , Hipercolesterolemia/genética , Hipercolesterolemia/patologia , Hipercolesterolemia/prevenção & controle , Interleucina-6/sangue , Camundongos , Camundongos Knockout , PPAR gama/agonistas , PPAR gama/genética , PPAR gama/metabolismo , Receptores de Angiotensina/sangue , Rosiglitazona , Fator de Necrose Tumoral alfa/sangueRESUMO
Recent evidence indicates that vascular progenitor cells may be the source of smooth muscle cells (SMCs) that accumulate in atherosclerotic lesions, but the origin of these progenitor cells is unknown. To explore the possibility of vascular progenitor cells existing in adults, a variety of tissues from ApoE-deficient mice were extensively examined. Immunohistochemical staining revealed that the adventitia in aortic roots harbored large numbers of cells having stem cell markers, e.g., Sca-1(+) (21%), c-kit(+) (9%), CD34(+) (15%), and Flk1(+) cells (4%), but not SSEA-1(+) embryonic stem cells. Explanted cultures of adventitial tissues using stem cell medium displayed a heterogeneous outgrowth, for example, islands of round-shaped cells surrounded by fibroblast-like cell monolayers. Isolated Sca-1(+) cells were able to differentiate into SMCs in response to PDGF-BB stimulation in vitro. When Sca-1(+) cells carrying the LacZ gene were transferred to the adventitial side of vein grafts in ApoE-deficient mice, beta-gal(+) cells were found in atherosclerotic lesions of the intima, and these cells enhanced the development of the lesions. Thus, a large population of vascular progenitor cells existing in the adventitia can differentiate into SMCs that contribute to atherosclerosis. Our findings indicate that ex vivo expansion of these progenitor cells may have implications for cellular, genetic, and tissue engineering approaches to vascular disease.
Assuntos
Apolipoproteínas E/deficiência , Arteriosclerose/patologia , Células-Tronco/citologia , Túnica Íntima/transplante , Veias/transplante , Animais , Aorta/citologia , Arteriosclerose/etiologia , Becaplermina , Biomarcadores , Artérias Carótidas/transplante , Diferenciação Celular , Linhagem da Célula , Células Cultivadas , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Músculo Liso Vascular/citologia , Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteínas Proto-Oncogênicas c-sis , Proteínas Recombinantes/metabolismo , Fatores de Tempo , Transplante Homólogo , Túnica Íntima/citologia , Túnica Íntima/metabolismo , Veias/citologia , Veias/efeitos da radiaçãoRESUMO
Recent data from animal models has demonstrated that both endothelial and smooth muscle progenitor cells contribute to the development of atherosclerosis. However, no data exists concerning the presence of progenitor cells in human atherosclerotic vessels. In the present study, a range of normal and atherosclerotic human arteries were collected from patients undergoing coronary artery bypass surgery. Segments of internal mammary artery (normal controls), and segments of proximal ascending aorta with visible fatty streak were analysed. Immunofluorescence was used to detect a panel of progenitor cell markers. A small number of progenitor cells were identified within neointimal lesions and the adventitia with variable expression of CD34, stem cell antigen (Sca-1), c-kit and VEGF receptor 2 (VEGFR2) markers, but no CD133 expression. On average there was a two- to three-fold increase in progenitor cell number in the adventitia of atherosclerotic vessels compared with normal controls, with a significant difference (p<0.05) in the frequency of cells expressing VEGFR2. Thus, we have provided the first evidence that vascular progenitor cells exist within atherosclerotic lesions, and identified an increased number of progenitor cells in the adventitia of human atherosclerotic vessels. These cells might be a source for smooth muscle cells (SMCs), macrophages and endothelial cells (ECs) that form atherosclerotic lesions.
Assuntos
Aorta/química , Aterosclerose/metabolismo , Biomarcadores/análise , Células-Tronco/química , Antígeno AC133 , Antígenos CD/análise , Antígenos CD34/análise , Aorta/patologia , Aterosclerose/patologia , Contagem de Células , Diferenciação Celular , Linhagem da Célula , Proliferação de Células , Tecido Conjuntivo/química , Células Endoteliais/química , Técnica Indireta de Fluorescência para Anticorpo , Glicoproteínas/análise , Humanos , Miócitos de Músculo Liso/química , Peptídeos/análise , Proteínas Proto-Oncogênicas c-kit/análise , Células-Tronco/patologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/análiseRESUMO
To search for novel transcriptional pathways that are activated in abdominal aortic aneurysm rupture, cDNA microarrays were used to compare global mRNA expression at the aneurysm rupture edge to anterior sac, and selected results were confirmed using quantitative real-time-polymerase chain reaction (QRT-PCR). This study identified apoptosis, angiogenesis, and inflammation as potentially important participants during the process of aneurysm rupture.
Assuntos
Aneurisma da Aorta Abdominal/genética , Ruptura Aórtica/genética , Expressão Gênica , Perfilação da Expressão Gênica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/genéticaRESUMO
Vein graft failure within the first month after bypass surgery is largely because of thrombosis. However, systemic study of thrombus formation in vein grafts is still lacking, and few effective techniques are available to prevent this event. Herein, we analyzed the kinetics of thrombosis and tested the effectiveness of locally applied aspirin on prevention of the disease in a mouse model. En face analysis of vein grafts revealed that 67+/-12% and 54+/-17% of the surface areas were covered by microthrombi at 1 and 3 days, respectively. Thrombus generation was also identified by labeling of platelets and fibrin, which occurred in 35 grafts examined at 1 and 3 days and 1, 2, 4, and 8 weeks. In a fifth of grafts, the thrombus occluded the vessel lumen by > or =1/4. Furthermore, a significant loss of endothelial cells was evidenced by beta-gal staining for vein grafts in transgenic mice expressing LacZ gene controlled by TIE2-endothelial specific gene promoter. Following thrombosis, neointimal lesions were significantly increased by 4-fold 2 weeks after the operation. When vein grafts were treated locally with aspirin in pluronic gel-127, the thrombus area was significantly reduced (P<0.005) at 1, 4, and 8 weeks. Interestingly, neointimal lesions were markedly reduced in the local, but not oral, aspirin-treated group at 4 and 8 weeks by 50% to 70% (P<0.005). The mechanism of reduced lesions by locally applied aspirin involved the protection of vein graft endothelium. Thus, we provide strong evidence that thrombus formation occurs before the development of neointimal lesions in vein grafts and that local aspirin treatment successfully reduces vein graft arteriosclerosis through endothelial protection, resulting in reduction of thrombosis.
Assuntos
Arteriosclerose/prevenção & controle , Aspirina/uso terapêutico , Implante de Prótese Vascular , Artérias Carótidas/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Fibrinolíticos/uso terapêutico , Oclusão de Enxerto Vascular/prevenção & controle , Inibidores da Agregação Plaquetária/uso terapêutico , Complicações Pós-Operatórias/prevenção & controle , Trombose/prevenção & controle , Túnica Íntima/patologia , Veias Cavas/efeitos dos fármacos , Animais , Arteriosclerose/etiologia , Aspirina/farmacologia , Artérias Carótidas/patologia , Artérias Carótidas/cirurgia , Modelos Animais de Doenças , Fibrinolíticos/farmacologia , Oclusão de Enxerto Vascular/etiologia , Hiperplasia , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Inibidores da Agregação Plaquetária/farmacologia , Complicações Pós-Operatórias/etiologia , Receptor TIE-2/deficiência , Receptor TIE-2/genética , Receptor TIE-2/fisiologia , Trombose/etiologia , Tromboxano B2/sangue , Túnica Íntima/efeitos dos fármacos , Veias Cavas/patologia , Veias Cavas/cirurgiaRESUMO
Accumulating evidence indicates the involvement of vascular progenitor cells in the development of arteriosclerosis, including transplant arteriosclerosis, angioplasty-induced restenosis, vein graft atherosclerosis, and spontaneous atherosclerosis. Recently, it was found that the adventitia of the arterial wall contains a large number of progenitor cells, which can differentiate into smooth muscle cells in vitro and in vivo. These progenitor cells were able to migrate from the adventitia into the intima, where they accumulate to contribute to atherosclerotic lesions of vein grafts in apoE-deficient mice. Thus, these cells may be a source of smooth muscle cells and might have implications for cellular, genetic, and tissue engineering approaches to vascular disease.
Assuntos
Tecido Conjuntivo/patologia , Células-Tronco/patologia , Túnica Íntima/patologia , Animais , Aorta , Arteriosclerose/etiologia , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Tecido Conjuntivo/fisiologia , Células Endoteliais , Humanos , Inflamação , Músculo Liso/citologia , Células-Tronco/fisiologia , Túnica Íntima/fisiologiaRESUMO
BACKGROUND: Mutations in endoglin or activin like kinase-1, both involved in the endothelial transforming growth factor-beta signaling pathway, cause the autosomal dominant bleeding disorder hereditary hemorrhagic telangiectasia. We and others have reported mouse models for this disease that share the characteristic phenotype of dilated vessels and sporadic hemorrhage. The reasons for the variable phenotype in hereditary hemorrhagic telangiectasia are not understood. METHODS AND RESULTS: After a detailed immunohistochemical analysis of 129/Ola mice, which are heterozygous for a targeted deletion in the endoglin gene, we observed intrinsic abnormalities in the vascular walls throughout the cutaneous vasculature. Postcapillary venules were dilated, and up to 70% of the vascular wall had no smooth muscle cells. The supporting layers of collagens and elastin were irregular, with thin areas, adding to the fragility of these vessels. A variable hemorrhagic phenotype was observed in which local bleeding is associated not only with fragile vessels but also with regions of inflammation. CONCLUSIONS: These findings have relevance to our understanding of the molecular basis of vascular integrity in a wide range of diseases.
Assuntos
Vasos Sanguíneos/anormalidades , Telangiectasia Hemorrágica Hereditária/patologia , Animais , Antígenos CD , Vasos Sanguíneos/patologia , Derme/irrigação sanguínea , Endoglina , Deleção de Genes , Imuno-Histoquímica , Camundongos , Camundongos Mutantes , Fenótipo , Receptores de Superfície Celular , Molécula 1 de Adesão de Célula Vascular/genéticaRESUMO
BACKGROUND: Since aortic diameter is the most -significant risk factor for rupture, we sought to identify stress-dependent changes in gene expression to illuminate novel molecular processes in aneurysm rupture. MATERIALS AND METHODS: We constructed finite element maps of abdominal computerized tomography scans (CTs) of seven abdominal aortic aneurysm (AAA) patients to map wall stress. Paired biopsies from high- and low-stress areas were collected at surgery using vascular landmarks as coordinates. Differential gene expression was evaluated by Illumina Array analysis, using the whole genome DNA-mediated, annealing, selection, extension, and ligation (DASL) gene chip (n = 3 paired samples). RESULTS: The sole significant candidate from this analysis, Lamin A/C, was validated at the protein level, using western blotting. Lamin A/C expression in the inferior mesenteric vein (IMV) of AAA patients was compared to a control group and in aortic smooth muscle cells in culture in response to physiological pulsatile stretch. -Areas of high wall stress (n = 7) correlate to those -regions which have the thinnest walls [778 µm (585-1120 µm)] in comparison to areas of lowest wall stress [1620 µm (962-2919 µm)]. Induced expression of Lamin A/C -correlated with areas of high wall stress from AAAs but was not significantly induced in the IMV from AAA patients compared to controls (n = 16). Stress-induced expression of Lamin A/C was mimicked by exposing aortic smooth muscle cells to prolonged pulsatile stretch. CONCLUSION: Lamin A/C protein is specifically increased in areas of high wall stress in AAA from patients, but is not increased on other vascular beds of aneurysm patients, suggesting that its elevation may be a compensatory response to the pathobiology leading to aneurysms.
RESUMO
There is strong epidemiological evidence that patients with diabetes have a lower incidence of abdominal aortic aneurysm. The precise mechanism of this negative association is unknown. Whilst a number of studies have supported the hypothesis that protection is a function of diabetes-mediated changes in the vascular extracellular matrix biology, there is also support for the idea that the treatment regimens used in diabetes may afford protection against AAA. In particular the pleiotropic drug family, the thiazolidinediones have been examined as candidates to ameliorate aneurysm formation. Both the thiazolidinediones, and the structurally related family, fibrates, have been shown to have anti-inflammatory and antioxidative effects, in addition to ability to modulatate glucose and lipid homeostasis. In this brief review we present the current data exploring the use of thiazolidinediones in experimental aneurysm development. Despite the fact that both thiazolidinediones Rosiglitazone and Pioglitazone are no longer prescribed in Europe and the US, they have provided important insights into the mechanism of action, and the application of other pleiotropic drugs in the treatment of AAA. One such pleiotropic drug is high-density lipoproteins (HDLs), which have been shown to have a broad spectrum of effects, including activation of PPARs, which may favour their use as a new drug target for protection against AAA development.
Assuntos
Aneurisma da Aorta Abdominal/prevenção & controle , Diabetes Mellitus/epidemiologia , Tiazolidinedionas/farmacologia , Animais , Aneurisma da Aorta Abdominal/epidemiologia , Diabetes Mellitus/tratamento farmacológico , Humanos , Hipoglicemiantes/farmacologia , Lipoproteínas HDL/metabolismo , Terapia de Alvo Molecular , Receptores Ativados por Proliferador de Peroxissomo/efeitos dos fármacos , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Pioglitazona , Fatores de Risco , RosiglitazonaRESUMO
OBJECTIVE: Development and rupture of aortic aneurysms (AA) is a complex process involving inflammation, cell death, tissue and matrix remodelling. The thiazolidinediones (TZDs) including Rosiglitazone (RGZ) are a family of drugs which act as agonists of the nuclear peroxisome proliferator-activated receptors and have a broad spectrum of effects on a number of biological processes in the cardiovascular system. In our previous study we have demonstrated that RGZ has a marked effect on both aneurysm rupture and development, however, the precise mechanism of this is unknown. METHODS AND RESULTS: In the present study, we examined possible targets of RGZ action in the early stages of Angiotensin II-induced AA in apolipoprotein E-deficient mice. For this purpose we employed immunoblotting, ELISA and antibody array approaches. We found that RGZ significantly inhibited c-Jun N-terminal kinase (JNK) phosphorylation and down-regulated toll-like receptor 4 (TLR4) expression at the site of lesion formation in response to Angiotensin II infusion in the initiation stage (6-72 h) of experimental AA development. Importantly, this effect was also associated with a decrease of CD4 antigen and reduction in production of TLR4/JNK-dependant proinflammatory chemokines MCP-1 and MIP-1α. CONCLUSION: These data suggest that RGZ can modulate inflammatory processes by blocking TLR4/JNK signalling in initiation stages of AA development.
Assuntos
Aneurisma Aórtico/induzido quimicamente , Proteínas Quinases JNK Ativadas por Mitógeno/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Tiazolidinedionas/farmacologia , Receptor 4 Toll-Like/antagonistas & inibidores , Angiotensina II , Animais , Aneurisma Aórtico/prevenção & controle , Ruptura Aórtica/prevenção & controle , Regulação para Baixo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Camundongos , Fosforilação/efeitos dos fármacos , Rosiglitazona , Receptor 4 Toll-Like/metabolismoRESUMO
BACKGROUND: Atrial fibrillation is a common arrhythmia, after cardiac surgery. Reperfusion injury and inflammation associated with cardiac surgery are thought to be involved in its pathogenesis. We hypothesized that cytoprotective effects associated with heat shock protein 70 (HSP70) could counteract these proarrhythmic insults. We therefore set out to examine the influence of heat shock protein 70 on the incidence of postoperative atrial fibrillation. METHODS: We prospectively recruited 80 patients undergoing elective coronary artery bypass surgery. Blood samples were collected preoperatively. Right atrial tissue was obtained at surgery. Incidence of postoperative atrial fibrillation and its duration were noted. Using a nested case-control design, 15 patients who developed atrial fibrillation were matched for operative procedure, age, sex, and beta-blocker usage, with 15 controls from the remaining patients. Atrial heat shock protein 70 was subsequently quantified by immunohistochemistry. Serum heat shock protein was measured using enzyme-linked immunosorbent assay and high sensitivity C-reactive protein was determined by immunoturbidometric assay. RESULTS: Intracellular HSP70 level was significantly higher in patients who did not develop atrial fibrillation (35 +/- 13 vs 19 +/- 15; p = 0.006). Atrial HSP70 level negatively correlated with atrial fibrillation; independent of other risk factors (odds ratio = 0.90; 95% confidence interval 0.84 to 0.99, p = 0.02). Serum HSP70 levels were similar in both groups (p = 0.81) and did not correlate with intracellular levels (p = 0.38). Preoperative C-reactive protein levels were similar in both groups (p = 0.93). CONCLUSIONS: Intracellular, but not serum, HSP70 level is negatively correlated with postoperative atrial fibrillation. This suggests a cardioprotective and an antiarrhythmic role for intracellular HSP70.