Aneurysm formation in experimental atherosclerosis: relationship to plaque evolution

Area of Science:

• Cardiovascular Research
• Primate Models of Atherosclerosis
• Vascular Biology

Background:

• Diet-induced atherosclerosis is a significant concern in primate research.
• Aneurysm formation is a potential complication of advanced atherosclerosis.
• Understanding the relationship between atherosclerosis and aneurysms is crucial for cardiovascular health.

Purpose of the Study:

• To investigate the occurrence of aneurysms in non-human primates with experimentally induced atherosclerosis.
• To determine the duration of atherogenic diet exposure required for aneurysm development.
• To explore the histological characteristics of aneurysms in this model.

Main Methods:

• Review of cynomolgus monkeys (n=268) and rhesus monkeys (n=175) fed atherogenic diets.
• Analysis of animals on normal, atherogenic, and regression diets with cholestyramine.
• Histological examination of affected arterial tissues.

Main Results:

• No aneurysms were observed in animals on normal diets or fed atherogenic diets for ≤12 months.
• Aneurysms formed in 13% of cynomolgus monkeys and 1% of rhesus monkeys after 16-24 months on an atherogenic regimen.
• Affected arteries included the aorta, innominate, carotid, iliac, and femoral arteries, with histological evidence of medial thinning and architectural loss.

Conclusions:

• Aneurysm formation is a manifestation of prolonged diet-induced atherosclerosis in primates.
• Aneurysms can develop even during cholesterol-lowering therapy, indicating a complex pathogenesis.
• Medial atrophy and plaque changes contribute to the development of aneurysms in this experimental model.