Healing of PTFE grafts in a pig model recruit neointimal cells from different sources and do not endothelialize.
OBJECTIVE
The aim of this study was to analyze the cellular sources for the neointima and the cell type that is lining the lumen in artificial grafts implanted in pigs.


METHODS
We used polytetrafluoroethylene grafts as bypasses from the common to the external iliac arteries. The animals were sacrificed after 1, 4, 7, 14, 21, 30, 60 and 90 days. Morphological, immunohistochemical and electron microscope assessments were made.


RESULTS
After 7 days a circumferential neoadventitia was formed. At day 14 isolated cellular islets of proliferating cells were observed on the luminal side of the graft without connection to the neoadventitia or the adjacent arteries. In the anastomotic regions at day 14 we observed an isolated neointima in contact with the adjacent artery. The cells lining the lumen had characteristics of both smooth muscle cells and endothelial cells.


CONCLUSIONS
Our study suggests that in artificial porcine grafts, the perivascular tissue, the blood and the adjacent artery contribute to the formation of the neointima. The luminal surface is covered by a hybrid cell with both smooth muscle cell and endothelial cell properties.
Mellander
S
S
Department of Vascular Surgery, Wallenberg Laboratory, The Cardiovascular Institute, Sahlgrenska Academy, Göteborg, Sweden.
Fogelstrand
P
P
Enocson
K
K
Johansson
B R
BR
Mattsson
E
E
D000199:Actins / Q000378:metabolism; D000714:Anastomosis, Surgical; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D001807:Blood Vessel Prosthesis; D002455:Cell Division; D004195:Disease Models, Animal; D005549:Foreign-Body Reaction / Q000378:metabolism / Q000473:pathology*; D007083:Iliac Artery / Q000378:metabolism / Q000601:surgery* / Q000648:ultrastructure; D007150:Immunohistochemistry; D007958:Leukocyte Count; D007962:Leukocytes / Q000648:ultrastructure; D008297:Male; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D011138:Polytetrafluoroethylene; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D015607:Stents; D013552:Swine; D017539:Tunica Intima / Q000378:metabolism / Q000648:ultrastructure*; D014945:Wound Healing / Q000502:physiology; D014841:von Willebrand Factor / Q000378:metabolism
D000199:Actins; D018809:Proliferating Cell Nuclear Antigen; D014841:von Willebrand Factor; D011138:Polytetrafluoroethylene