Atrophic Remodeling of the Artery-Cuffed Artery

Increased arterial wall tension stimulates growth and remodeling of arteries, but little is known about the effects of decreased wall tension, despite its developmental and pathological significance. Consequently, we cuffed 1 carotid artery in rabbits with a portion of the contralateral artery to off-load circumferential wall tension. The model produced rapid and extensive atrophy of the cuffed artery that yielded decreases in the DNA content of the cuffed artery (a measure of cell number) from 8.0+/-0.5 microgram/cm of in situ vessel length to 5.6+/-0.5 microgram/cm at 21 days postoperatively. The elastin content of the cuffed artery was also significantly reduced, from 399+/-17 to 283+/-17 microgram/cm, and collagen content was reduced from 468.0+/-59.0 to 154+/-24 microgram/cm (P<0.05) at 21 days postoperatively. Detection of DNA oligonucleosomes by gel electrophoresis implicated apoptotic cell death in remodeling due to cuffing. Upregulation of matrix metalloproteinases (MMPs), including MMP-2, MMP-9, and unidentified gelatinases, indicated that these enzymes may also be involved in remodeling. No further changes in wall structure were seen between 3 weeks and 6 months, and the excised artery that was used as a cuff exhibited normal medial morphology for at least 6 months postoperatively. We infer from these experiments that off-loading of arterial wall tension induces rapid and extensive atrophy of the arterial media.