The Journal of Thoracic and Cardiovascular Surgery, Vol 90, 378-386, Copyright © 1985 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Arterial wall regeneration in small-caliber vascular grafts in rats. Neoendothelial healing and prostacyclin production
B van der Lei, H Darius, K Schror, P Nieuwenhuis, I Molenaar and CR Wildevuur
Clinically available synthetic graft materials frequently fail when used as
a small-caliber arterial substitute. Therefore, we developed a new type of
graft material, prepared from a mixture of polyurethane and poly-L-lactic
acid, to be used as a scaffold for the regeneration of the arterial wall.
In this study microporous, compliant, biodegradable
polyurethane/poly-L-lactic acid grafts (n = 16) and polytetrafluoroethylene
grafts (n = 16) were implanted in the rat abdominal aorta and evaluated 3,
6, and 12 weeks after implantation. First, we evaluated the extent of
neoendothelial healing (n = 8) by means of light microscopy and scanning
electron microscopy. Next, we studied the ability of the neoendothelial
cells to produce prostacyclin (n = 8) by means of bioassay for prostacyclin
and radioimmunoassay for its stable hydrolysis product, 6-oxo-prostaglandin
F1 alpha. There were no significant differences between the two graft types
in the amount of prostacyclin production per unit graft area covered with
neoendothelium, and this amount was the same as for normal endothelium.
However, the polytetrafluoroethylene grafts showed incomplete
neoendothelial healing, even after 12 weeks of implantation, in contrast to
the polyurethane/poly-L-lactic acid grafts. The better healing
characteristics of the polyurethane/poly-L-lactic acid grafts ensured the
fast development of a complete neoarterial wall, possessing strength,
compliance, and thromboresistance equivalent to normal arterial wall
tissue. These results demonstrate that arterial wall tissue regeneration in
polyurethane/poly-L-lactic acid grafts may open new perspectives in the
field of arterial reconstructive surgery.