Smooth muscle cells (SMC) of normal and varicose human saphenous intima were studied on cryostat sections by immunohistochemistry with alpha-smooth muscle actin (ASMA), type IV collagen, and laminin antibodies and also by transmission electron microscopy. The findings suggest two structurally distinct subtypes of smooth muscle cells with thin and thicker external lamina. Thin external lamina SMC were characterized by laminin, type IV collagen, weaker external lamina reactivity, and intense cytoplasmic alpha-smooth muscle actin immunoreactivity. Ultrastructurally, they exhibited abundant cytoplasmic microfilaments and thin external lamina. These cells were found isolated or, more frequently, clustered in fascicles close to the subendothelium in focal or zonal cushions, or in diffuse enlargement of the intima. In contrast, thicker external lamina smooth muscle cells were intensely immunolabeled for laminin and collagen IV, showing irregular cytoplasmic ASMA reaction. Single or clustered thicker external lamina SMC were seen predominantly in zonal cushions and in intima diffuse enlargement. It is very likely that these cells secrete these matrices in a nonpolarized fashion. The thicker external lamina of these SMCs showed a fine granular amorphous aspect sometimes intermingled with microfibrils. These external lamina were interposed between neighboring cells and exposed to collagen fibrils and elastic fibers. The cells also exhibited rarefaction of the cytoplasmic filaments. Intermediary cells exhibiting both features were rarely seen. Thicker external lamina SMC should be discussed in the context of an adaptive/proliferative response leading to dysfunction of the fibroelastic properties of the vein wall.
CONTEXTO: A relação entre trombose venosa profunda e trombofilia tem sido pouco estudada em indivíduos portadores de compressão da veia ilíaca comum esquerda, conhecida clinicamente como síndrome de May-Thurner. OBJETIVO: Avaliar a prevalência de marcadores de trombofilia nos pacientes portadores de síndrome de May-Thurner e trombose de veia ilíaca comum esquerda. MÉTODOS: Entre março de 1999 e dezembro de 2008, 20 pacientes com síndrome de May-Thurner e trombose de veia ilíaca comum esquerda foram avaliados retrospectivamente quanto à presença de marcadores de trombofilia. RESULTADOS: Foi detectada a associação entre síndrome de May-Thurner e marcadores de trombofilia em 8 pacientes (40%). CONCLUSÃO: A presença de marcadores de trombofilia em pacientes com trombose de veia ilíaca comum esquerda e síndrome de May-Thurner é frequente, porém não difere da prevalência encontrada em pacientes portadores de trombose venosa profunda sem a síndrome associada.
Varicose veins alternate areas of phlebosclerosis and hypertrophy of the vein wall. In this study, samples of long saphenous veins obtained from patients submitted for aortocoronary saphenous vein graft or for surgical resection of varicose saphenous veins were examined. Histologic changes in the intima, muscle, and adventitial layers were quantified. Thicknesses of the venous wall layers were obtained by linear measurements, and the volumetric density of the connective tissue in the muscle layer was determined by point counting. The muscle layer thickness was 300 +/- 13 and 581 +/- 25 microns in normal and varicose veins, respectively. A more severe connective tissue accumulation within the muscle bundles was found in the varicose condition. The volumetric density of the connective tissue in the circular muscle layer (CmC/MmC) showed also a marked difference between varicose (0.67 +/- 0.08) and normal veins (0.43 +/- 0.02), P < 0.05. The authors suggest that the varicose condition is associated with a connective tissue uniform accumulation among muscle cells in the circular muscle layer.
CONTEXTO: Os autores apresentam uma análise epidemiológica sobre a investigação de marcadores de trombofilia em pacientes que apresentaram eventos trombóticos arteriais e/ou venosos acompanhados no Departamento de Angiologia e de Cirurgia Vascular do CENTERVASC no período de janeiro de 2001 a janeiro de 2007. OBJETIVO: Avaliar a prevalência de marcadores de trombofilias congênitas ou adquiridas nos eventos trombóticos venosos e/ou arteriais. MÉTODOS: Entre janeiro de 2001 e janeiro de 2007, 224 pacientes com eventos trombóticos venosos e/ou arteriais foram submetidos a uma rotina de investigação quanto à presença ou não de marcadores de trombofilia, independentemente da idade e história familiar dos pacientes, topografia do evento e presença ou ausência de fatores trombogênicos extrínsecos. RESULTADOS: Foram detectados marcadores de trombofilia em 112 pacientes (50% dos casos). Nestes, observou-se de modo predominante a positividade para anticorpos antifosfolipídios, anticardiolipina e/ou anticoagulante lúpico (39 casos), bem como a presença do fator V de Leiden (43 casos). O sistema venoso foi significativamente o mais acometido, e a ocorrência associada com condições trombogênicas extrínsecas esteve presente em 56 (50%) dos portadores de marcadores de trombofilias. CONCLUSÕES: A presença de marcadores de trombofilia nos pacientes com eventos trombóticos, venosos e/ou arteriais, independentemente da faixa etária ou da existência de fatores extrínsecos associados, foi significativa.
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