Compliance and biodegradation of vascular grafts stimulate the regeneration of elastic laminae in neoarterial tissue: an experimental study in rats.
Microporous vascular grafts that are compliant and biodegradable can function as scaffolds for the regeneration of the arterial wall in small-caliber arteries. The purpose of this study was to determine the specific influence of both compliance and biodegradation of microporous vascular grafts on this regeneration, especially on the regeneration of elastic laminae. Therefore we implanted three different types of microporous vascular grafts into the abdominal aorta of rats. These grafts were (I) compliant, biodegradable (group I; n = 6), (II) compliant, biostable (group II; n = 8), and (III) noncompliant, biodegradable (group III; n = 8). Six weeks after implantation the implants were evaluated by means of light microscopy and electron microscopy. The compliance of the implants, as indicated by arterial pulsations, was well maintained in group I but not in group II. In all groups a neomedia had regenerated, composed of smooth muscle cells that were predominantly longitudinally arranged. Elastic laminae were present almost throughout the neomedia in group I, restricted to the luminal layers of the neomedia in group II, and totally absent in the neomedia of group III. These results demonstrate that both compliance and biodegradation stimulate the regeneration of elastic laminae in neoarterial tissue. Because of the compliance of microporous vascular grafts, smooth muscle cells are mechanically stimulated by the arterial pulsations to produce elastin arranged in laminae. Because of the biodegradation of these grafts, compliance is maintained, which therefore favors the regeneration of elastic laminae.
D000818:Animals; D001012:Aorta, Abdominal / Q000502:physiology*; D001672:Biocompatible Materials; D001673:Biodegradation, Environmental; D001807:Blood Vessel Prosthesis; D003187:Compliance; D004549:Elastin / Q000096:biosynthesis; D008297:Male; D008854:Microscopy, Electron; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D019736:Prostheses and Implants; D051381:Rats; D011919:Rats, Inbred Strains; D012038:Regeneration; D013997:Time Factors; D014655:Vascular Resistance
D001672:Biocompatible Materials; D004549:Elastin