The Contribution of Resident Vascular Stem Cells to Arterial Pathology

Intimal accumulation of smooth muscle cells contributes to the development and progression of atherosclerotic lesions and restenosis following endovascular procedures. Arterial smooth muscle cells display heterogeneous phenotypes in both physiological and pathological conditions. In response to injury, dedifferentiated or synthetic smooth muscle cells proliferate and migrate from the tunica media into the intima. As a consequence, smooth muscle cells in vascular lesions show a prevalent dedifferentiated phenotype compared to the contractile appearance of normal media smooth muscle cells. The discovery of abundant stem antigen-expressing cells in vascular lesions also rarely detected in the tunica media of normal adult vessels stimulated a great scientific debate concerning the possibility that proliferating vascular wall-resident stem cells accumulate into the neointima and contribute to the progression of lesions. Although several experimental studies support this hypothesis, others researchers suggest a positive effect of stem cells on plaque stabilization. So, the real contribute of vascular wall-resident stem cells to pathological vascular remodelling needs further investigation. This review will examine the evidence and the contribution of vascular wall-resident stem cells to arterial pathobiology, in order to address future investigations as potential therapeutic target to prevent the progression of vascular diseases.

Arterite de Takayasu: aspectos clínicos e terapêuticos em 36 pacientes / Takayasu's arteritis: clinical and therapeutic aspects in 36 patients

CONTEXTO: A arterite de Takayasu é uma vasculite crônica, geralmente com diagnóstico tardio devido à pouca especificidade dos sintomas durante a fase inicial do acometimento vascular. A terapêutica de eleição é o uso de imunossupressores. O procedimento cirúrgico, quando necessário, é sempre evitado na fase aguda. OBJETIVO: Descrever alterações clínicas, laboratoriais e vasculares de arterite de Takayasu no período de 1977 a 2006. MÉTODO: A amostra compreendeu 36 pacientes - 10 brancos, 35 mulheres, idade média de 31,7 anos (±13,7), com prevalência significante na quarta década (p < 0,005). Evolução de 3 anos e período até o diagnóstico de 7,9 anos. Velocidade de hemossedimentação (VHS) e proteína C reativa (PCR) avaliaram atividade da doença, e o duplex scan aferiu a espessura médio- intimal da artéria carótida. RESULTADOS: Hipertensão arterial sistêmica e claudicação de membros superiores e inferiores foram ressaltados em 85,2, 69,5 e 30,5 por cento, respectivamente. O resultado da VHS foi > 60 mm em 50 por cento da amostra (p < 0,005). PCR mg/dL foi realizado em 18, variando de 0,4-25 na admissão para 0,11-1,9 na evolução. Doença auto-imune, tuberculose e HIV correlacionaram-se em 19,4, 8,3 e 2,7 por cento, respectivamente. Lesões aórticas foram significativas em 22 por cento (quatro oclusões, dois aneurismas infra-renais, um torácico). Em 19,4 por cento, foram acometidas artérias renais e subclávias uma oclusão bilateral de carótidas, e em 25 por cento os membros inferiores. A espessura médio-intimal da carótida comum foi estratificada em: > 3 mm, < 3 e > 1,7, < 1,7 e > 1,2 e < 1,2 mm, representando 41,6, 19,4, 8,37 e 30,50 por cento, respectivamente (p < 0,005). Glicocorticóides foram utilizados em 61,1 por cento, azatioprina em 16.6 por cento, e associada a ciclofosfamida em 8,3 por cento. Procedimento cirúrgico ou endovascular foi realizado em 30,5 por cento com dois óbitos por complicações cardiovasculares. CONCLUSÕES: A VHS,...

BACKGROUND: Takayasu arteritis is a chronic vasculitis often with delayed diagnosis due to the nonspecific presentation of clinical symptoms in its initial phase. Treatment includes imunosuppression drugs. Surgical treatment, when necessary, should be avoided in the acute phase. OBJECTIVE: To describe clinical, laboratory and vascular findings in Takayasu's arteritis from 1977 through 2006. METHODS: The sample was comprised of 36 patients (10 Caucasians, 35 women), mean age of 31.7 (±13.7) years, and significant prevalence in the forth decade (p < 0.005). Disease course was 3 years and time until diagnosis was 7.9 years. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were used to assess disease activity, and duplex scan to measure carotid artery intima-media wall thickness. RESULTS: Hypertension was present in 85.2 percent, and upper and lower limb claudication in 69.5 and 30.5 percent, respectively. ESR was > 60 mm in 50 percent of the sample (p < 0.005). PCR mg/dL was performed in 18 cases, ranging from 0.4-25 on admission to 0.11-1.9 during disease course. Autoimmune diseases, tuberculosis and HIV correlated in 19.4, 8.3 and 2.7 percent, respectively. Major aortic lesions were detected in 22.2 percent (four occlusions, two infrarenal aneurysms, one thoracic aneurysm). Other arteries involved renal, subclavian and one carotid occlusion (19 percent), and some level of lower limb occlusion (25 percent). Intima-media thickness was stratified in > 3 mm (41.6 percent), < 3 and > 1.7 (19.4 percent), < 1.7 and > 1.2 (8.37 percent), and < 1.2 mm (30.50 percent) (p < 0.005). Glucocorticoids were used in 61 percent, azathioprine in 16.6 percent, and azathioprine combined with cyclophosphamide in 8.3 percent. Surgical and endovascular procedures were performed in 30.5 percent. Two patients died due to cardiovascular diseases. CONCLUSIONS: Carotid intima-media thickness, PCR, and ESR are important markers for the follow-up of...