A Model of Primary Atherosclerosis and Post-Angioplasty Restenosis in Mice

Abstract

Although mice deficient in various genes are providing greater insight into the mechanisms of restenosis after angioplasty, there have been limitations with murine models not simulating human vascular disease. To develop a more clinically applicable model of primary atherosclerosis and restenosis following angioplasty of the primary lesion, we fed apolipoprotein E-deficient mice a Western diet and occluded the left common carotid artery for 2 days. Three weeks after flow was restored, the temporarily occluded carotids demonstrated atherosclerotic lesions containing foam cells, cholesterol clefts, necrotic cores, and fibrous capsules. The atherosclerotic carotids in other animals underwent angioplasty with a beaded probe, resulting in plaque and medial layer disruption. Three weeks after angioplasty, although there was significant neointimal lesion formation, the luminal narrowing did not change significantly secondary to overall vessel enlargement (positive remodeling). Neointimal lesions were composed of smooth-muscle cells and extracellular matrix observed adjacent to the original atherosclerotic plaques. Similarly, even at 3 months after the angioplasty the lumen was maintained despite greater neointimal lesion formation caused by progressive positive remodeling. This new murine model of primary atherosclerosis and postangioplasty intimal hyperplasia and remodeling mimics the human disease pattern of postangioplasty intimal hyperplasia. Used in transgenic animals, this model will likely facilitate understanding of the mechanisms of restenosis in humans.

Matrix Metalloproteinase-9 Modulation by Resident Arterial Cells Is Responsible for Injury-Induced Accelerated Atherosclerotic Plaque Development in Apolipoprotein E–Deficient Mice

“…13 This approach with a focal mechanical injury at the site of the temporary ligation generates a significant atherosclerotic plaque in 3 weeks compared with the 6 to 12 months needed for de novo plaque development on high-fat diet alone. Using this model of focally accelerated atherosclerotic plaque formation, we demonstrate that a lack of MMP-9 led to a reduction in atherosclerotic plaque volume and, more significantly, to a reduction in intraplaque cell accumulation of resident cells and bone marrow-derived cells in the apoE…”

“…Southern blots of tail DNA for germline transmission of the MMP-9 allele was performed as described previously. 12 RT-PCR of tail DNA was performed for the apoE allele as described previously 13 and confirmed by serum cholesterol levels on regular chow. F3 mice were then generated from F2 breeding pairs of dKO and sKO mice and genotyped again by RT-PCR of tail DNA for the MMP-9 and apoE alleles before any use.…”

“…One week before the surgery (temporary ligation placed on the middle of the left common carotid artery), 13 animals were started on a high-fat diet (42% of total calories from fat; 0.15% cholesterol; Harlan-Teklad; Madison, Wis). The ligature was removed after 2 days, restoring the carotid blood flow.…”

“…At 0 days (sham surgery without ligation), 2 days (restoration of flow), 4 days, 7 days, and 3 weeks, animals were euthanized, and carotid arteries were either harvested for zymography (snap-frozen) or were perfusion-fixed via the left ventricle at 100 mm Hg pressure as described previously. 13 Before perfusion fixation, blood was drawn from the left ventricle for analysis of levels with use of an Affinity Cholesterol Reagent Procedure 402 (Sigma-Aldrich). Standards were obtained from a cholesterol standard solution (200 mg/dL; Wako Chemicals).…”

CKD Accelerates Development of Neointimal Hyperplasia in Arteriovenous Fistulas

“…Three weeks after AV fistula creation, we euthanized the animals, and the AV anastomoses were perfusion-fixed via the left ventricle at 100 mmHg pressure as described previously. 37 Before perfusion fixation, we drew blood from the left ventricle for the biochemical analysis. BUN, phosphorus, and calcium were measured by autoanalyzer techniques in the Animal Facility Clinical Laboratory at Washington University in St. Louis, Missouri.…”