RESUMO
BACKGROUND/AIMS: Angiogenesis is a feature of the atherogenic process, with intimal neovascularisation arising from vessels in the adventitia, adjacent to a plaque. Immature, leaky blood vessels from unstable plaques proliferate abnormally and, being poorly invested with smooth muscle cells, may contribute to instability of the plaque by facilitation of inflammatory cell infiltration and haemorrhagic complications. METHODS: We used laser-capture microdissection to isolate angiogenic areas of the extracellular matrix (containing CD105/flt-1-positive, fragile thin-walled vessels) and non-angiogenic vascular areas (CD105-negative, with smooth muscle cell covering) of complicated endarterectomy plaques, and specifically designed angiogenesis-TaqMan real-time PCR microarrays to identify gene expression. RESULTS: Important pro-angiogenic components, including Notch-3, delta-like-4 (DLL4), Tie-2, angiopoietin-1 (Angio-1) and receptor for advanced glycation end products (RAGE), and one anti-angiogenic factor, endostatin, were up-regulated in these regions. Immunohistochemistry demonstrated localisation within intimal, active (CD105-positive) microvessels and co-localisation of Notch-3 and DLL4/Tie-2 and Angio-1 in the same vessels indicating multiple/synergistic signalling mechanisms associated with vessel development. CONCLUSION: These data, although providing only a snapshot of information, demonstrate that plaque vascularisation occurs in the presence of multiple angiogenically active factors. Knowledge of their combined effects could help in the formulation of novel therapeutics designed to stabilise or prevent their formation in the treatment of atherosclerosis.
Assuntos
Proteínas Angiogênicas/genética , Estenose das Carótidas/genética , Dissecação/instrumentação , Perfilação da Expressão Gênica/métodos , Marcadores Genéticos , Lasers , Neovascularização Fisiológica/genética , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Proteínas Adaptadoras de Transdução de Sinal , Idoso , Proteínas Angiogênicas/análise , Angiopoietina-1/genética , Antígenos CD/análise , Proteínas de Ligação ao Cálcio , Artérias Carótidas/química , Artérias Carótidas/imunologia , Artérias Carótidas/cirurgia , Estenose das Carótidas/imunologia , Estenose das Carótidas/fisiopatologia , Estenose das Carótidas/cirurgia , Endarterectomia das Carótidas , Endoglina , Endostatinas/genética , Humanos , Imuno-Histoquímica , Peptídeos e Proteínas de Sinalização Intercelular/genética , Masculino , Pessoa de Meia-Idade , Receptor para Produtos Finais de Glicação Avançada , Receptor Notch3 , Receptor TIE-2/genética , Receptores de Superfície Celular/análise , Receptores Imunológicos/genética , Receptores Notch/genética , Ruptura , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genéticaRESUMO
OBJECTIVES: Recovery from stroke is dependent on the survival of neurons in the dynamic peri-infarcted region. Although several markers of neuronal injury and apoptotic cell death have been described, administration of neuroprotective drugs directed at specific molecules has had limited success. A complete understanding of deregulated genes associated with neuronal death would be beneficial. Our previous microarray studies identified increased expression of a novel protein, the B-cell translocation gene 2 (BTG2), in infarcted regions. METHODS: We have used immunohistochemistry and Western blotting to examine the expression and localization of BTG2 in stroked brain tissue and immunofluorescent staining of human fetal brain neurons to determine if oxygen-glucose deprivation affected its expression. RESULTS: We show that BTG2 is strongly expressed in peri-infarcted and infarcted regions of brain tissue, localizing in neuronal nuclei and cytoplasm, whilst being absent or very weakly expressed in normal looking contralateral tissue. Exposure of human fetal brain neurons to oxygen-glucose deprivation also induced BTG2 expression in the cytoplasm and perinuclear regions of cells staining positive for propidium iodide (a marker of nuclear damage). CONCLUSIONS: BTG2 may be a modulator of cell survival and differentiation and could help to protect against cell death by inhibition of necrosis and/or apoptotic signalling pathways.