RESUMO
BACKGROUND: The aim of the study was to analyze the mechanism of deterioration of implanted arteries. METHODS: Eleven patients were included. Samples of vascular segments obtained from multiorgan donors and samples of the same vascular segments after explantation in the recipient were analyzed. Blood group, time of cold and warm ischemia, cause of death, time spent in the intensive care unit, time of storage of the cryopreserved grafts, and anatomopathological and immunohistochemical studies were analyzed using the preimplant samples obtained from the multiorgan donor. For samples obtained from the recipient, blood group, duration for which the tissue from the donor has been implanted, reason for graft explantation, and anatomopathological and immunohistochemical studies were analyzed. RESULTS: Histopathologically, the main finding has been the substitution of the muscular cap of the arterial wall by an intense fibrosis, in most of the cases, of a symmetrical nature. Besides this degeneration of myocytes, there is marked perivascular fibrosis and fibrointimal thickening also exists. The T lymphocytes suggest the importance of the immunological mechanism in the distortion of the architecture of the arteries. The atherosclerosis plays a less relevant role. CONCLUSIONS: Evidence of immune-mediated injury was found, and this mechanism seems to be responsible for the degenerative process in cryopreserved homografts.
Assuntos
Artérias/transplante , Bioprótese , Implante de Prótese Vascular/efeitos adversos , Criopreservação , Rejeição de Enxerto/etiologia , Imuno-Histoquímica , Linfócitos T/imunologia , Antígenos CD/análise , Artérias/imunologia , Artérias/patologia , Biomarcadores/análise , Fibrose , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Humanos , Músculo Liso Vascular/imunologia , Músculo Liso Vascular/patologia , Músculo Liso Vascular/transplante , Espanha , Fatores de TempoRESUMO
Limbal stem cells (LSC) have an important role in the maintenance of the corneal surface epithelium, and autologous cultured limbal epithelial cell (HLECs) transplantations have contributed substantially to the treatment of the visually disabling condition known as LSC deficiency. A major challenge is the ability to identify LSC in vitro and in situ, and one of the major controversies in the field relates to reliable LSC markers. This study was carried out to evaluate the culture of a limbal biopsy on human amniotic membrane (HAM): directly on the chorionic side and on intact epithelium, and the expression of the stem cell associated markers: ABCG2, p63. HAM has been extensively used for ocular surface reconstruction and has properties which facilitate the growth of epithelial cells controlling inflammation and scarring.