Identification of dendritic cells in ePTFE grafts explanted from humans
Introduction
The clinical results with small diameter synthetic grafts remains inferior to that of autologous vein or artery for bypass procedures 1, 2, 3, 4. Many different synthetic materials have been used in recent years in both animal and clinical studies, however, their use is limited by occlusion due to thrombus formation and by the development of neointimal hyperplasia 5, 6, 7, 8, 9.
Following the implantation of a synthetic vascular prosthesis into the bloodstream, a sequence of events take place involving, in particular, the accumulation of immunocompetent cells, including lymphocytes and macrophages 10, 11, 12, 13, 14, 15, 16, 17. Theoretically, dendritic cells, which are potent antigen-presenting cells 18, 19, may also be involved in this immune response to synthetic grafts. However, the involvement of dendritic cells in this immuno-inflammatory response has not been studied previously.
The aim of this study was to examine small diameter synthetic ePTFE (Goretex®, WL Gore and Assoc, Inc., Flagstaff, AZ, USA) grafts explanted from humans for the presence of immuno-inflammatory cells and specifically for cells with dendritic morphology. We considered that dendritic cells may promote and regulate the inflammatory response by invading the vascular prostheses and may therefore contribute to graft failure.
Section snippets
Materials and methods
Materials were collected in accordance with the principles outlined in the Declaration of Helsinki [20]and this study was approved by the Institutional Review Board of St Vincent's Hospital, Sydney, Australia.
Characteristics of the luminal surface of the ePTFE grafts
Examination of haematoxylin stained sections showed that neointima was consistently present on the luminal surface of the grafts at the anastomotic regions. However, the thickness of the neointima gradually diminished at distances further from the anastomoses and the central regions of the grafts were consistently free of neointima in all cases.
Within the anastomotic areas and within the immediately adjacent areas, the thickness of the neointimal layer varied markedly, but in all grafts, the
Discussion
The main observation of the present study is that dendritic cells accumulate within the ePTFE vascular grafts. The finding of dendritic cells, associated with T-lymphocytes, within the synthetic vascular grafts suggests that dendritic cells may be important in immuno-inflammatory reactions associated with the implantation of foreign materials into the vascular system. Our immunohistochemical observations showed that the number of S-100+ dendritic cells accumulating within the synthetic grafts
Acknowledgements
We thank the St Vincent's Clinic Foundation, Sydney, Australia for financial support.
References (40)
- et al.
Distal anastomotic intimal hyperplasia: histopathologic character and biogenesis
Annals of Vascular Surgery
(1989) - et al.
Atherosclerosis in vascular grafts for peripheral vascular disease. Part 2. Synthetic vascular prostheses
Atherosclerosis
(1986) - et al.
Biomaterial biocompatibility and the macrophage
Biomaterials
(1984) - et al.
Acute platelet deposition after carotid endarterectomy in sheep: vein patch compared with gelatin-sealed Dacron and polytetrafluoroethylene patch closure
Journal of Vascular Surgery
(1996) Dendritic cells: unique leucocyte populations which control the primary immune response
Blood
(1997)- et al.
Immunophenotypic analysis of the aortic aneurysm wall suggests that vascular dendritic cells are involved in immune responses
Cardiovascular Surgery
(1998) - et al.
Mechanisms of healing in synthetic grafts
Journal of Vascular Surgery
(1987) - et al.
Platelet reactivity in human aortic grafts: a prospective, randomized midterm study of platelet adherence and release products in Dacron and polytetrafluoroethylene conduits
Journal of Vascular Surgery
(1989) - et al.
Subendothelial layer of pseudointima of polytetrafluoroethylene graft is formed by transformation of fibroblasts migrated from extravascular space
European Journal of Vascular Surgery
(1994) - et al.
An appraisal of the role of the PTFE graft in lower limb arterial reconstruction
Australian and New Zealand Journal of Surgery
(1984)