Browsing by Subject "Intima1 hyperplasia"

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    Assessment of cyclosporine A-induced ultrastructural changes in vascular wall using an experimental arterial autograft model
    (Murcia : F. Hernández, 1995) Buján, J.; Bellón, J.M.; Jurado, F.; Hernando, A.; Contreras, L.A.
    The objective of this ultrastructural study was to assess the effects of cyclosporine A (CsA) in an experimental model of arterial autograft. Fifty female Sprague-Dawley rats weighing 250-300 g were employed. Using a microsurgical technique, an arterial autograft measuring approximately 5 mm in length was placed in the right common iliac artery. Two groups were established: group 1 (control), consisting of 25 animals subjected only to arterial autograft; and group 11 (pre- and postoperative CsA), also consisting of 25 animals which received a daily subcutaneous dose of 5 mg/kg CsA (Sandimmun, sandozB) on the four days preceding the surgery and thereafter, until sacrifice. The animals were sacrificed on postoperative day 7, 14,21,30 and 50. The specimens (autografts) obtained were studied under transmission and scanning electron microscopes. In the control group, the process of endothelialization of the graft was completed by day 14. In the CsA-treated group, restoration of the endothelium took 50 days. The development of intima1 hyperplasia was delayed in the treated group. There were no morphological changes in its structure when compared to the control group* The tunica mewith loss of smooth muscle cells, fragmentation and lysis of the elastic lamina, presence of lipid-filled macrophages, and muscle cells with cytoplasmic lipid vacuoles. In our opinion, these results suggest that the action of CsA mainly targets on the endothelium and smooth muscle cells, exerting a toxic effect in an in vivo arterial graft model.dia had thinned in the treated grafts
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    Lack of intimal hyperplasia response in an experimental model of non-endothelial vascular wall damage
    (Murcia : F. Hernández, 1992) Buján, J.; Bellón, J.M.; Golittsin, A.; Gianonatti, M.C.; Turegano, F.
    The endothelial and media1 layers are generally presumed to play an important role in the appearance and development of intimal hyperplasia. We have carried out a short-, media- and long-term study of the morphological changes taking place in the comrnon iliac artery of rats after surgical removal of the adventitial layer. Our aim has been to assess the likely role played by this layer in the development of intimal hyperplasia. Our results show recurrent periods of cellular desquamation and almost complete absence of hyperplastic response during the first two months. After three months three is a slow process of endothelialization which is completed by the 6th month and persists one year after adventitial resection. Thus, adventitial resection seems to cause instability at the subendothelial bed level, not allowing the junction and embedding of endothelial cells nor the development of intimal hyperplasia. This lack of hyperplasia might also result from the fact that the endothelial desquamation process does not involve cellular rupture, which would prevent mitogenic-factor release. After morphological repair of the endothelium, a slow morphofunctional recovery of the artery takes place