Canine Peripheral Vascular Arteriosclerosis Following Myointimal Fragmentation and Atherogenic Diet

Abstract

The development of arteriosclerotic peripheral vascular lesions following balloon catheter and mechanical fragmentation of the arterial myointima combined with an atherogenic diet was studied in a canine model. The ileofemoral arteries of five mongrel dogs (mean wt 22 × 2 kg) were selectively cannulated and subjected to balloon catheter and mechanical myointimal injury by repeated longitudinal and transverse shearing forces. Twenty grams of hydrogenated coconut oil and a 5.0% cholesterol diet were fed to the animals daily during the study period. Followup angiographic studies obtained at 4 weeks (n= 2), 10 weeks (n= 3), 16 weeks (n= 3), and 24 weeks (n= 2) demonstrated changes of progressive peripheral vascular occlusion. Concurrent duplex Doppler studies correlated well with the angiographic results. At 10 (n= 1), 18 (n= 2), and 24 (n= 2) weeks, the animals were sacrificed and the vessels were perfusion-fixed in situ with 2% glutaraldehyde or formaldehyde solutions and excised. Histological examination demonstrated extensive arteriosclerotic changes including (i) fragmentation and reduplication of the internal elastic membrane, (ii) myointimal hyperplasia with fibroblastic proliferation including the development of fibrous intimal plaques, and (iii) transmigration and proliferation of smooth muscle cells with scattered monohistiocytes. The specimens showed a range of stenotic changes from 25% to total occlusion of the vascular lumen. These preliminary data demonstrate the feasibility of providing intense arteriosclerotic myointimal histologic changes in the canine peripheral vasculature within a 24-week period. Further refinement of this methodology may provide a practical model for studies of localized peripheral vascular occlusive disease

Key Words:

• Arteriosclerosis
• myointima
• cholesterol
• coconut oil
• internal elastic membrane
• smooth muscle cells
• fibrocytes