Identification of the atherosclerosis phenotype in vivo by vascular duplex ultrasonography in ApoE-deficient dogs

BACKGROUND AND AIMS: This study evaluated the atherosclerosis phenotype by vascular duplex ultrasonography (VDU) in ApoE-deficient dogs. METHODS: A total of 108 beagle dogs were examined by VDU, which included 32 wild-type, 68 heterozygous (ApoE-/+) mutant and 8 homozygous (ApoE−/−) mutant dogs. According to age, wild-type and ApoE-/+ dogs were divided into two subgroups: young (6–15 months) and adult dogs (18–29 months). All homozygous dogs were young dogs. Dogs were feed with normal diet. The plasma lipid levels were tested. The diameter of the common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA), abdominal aorta and common iliac artery (CIA) and the intima-media thickness (IMT) of the CCA and abdominal aorta were measured by VDU. The artery sections of ApoE−/− and control dogs were analyzed by histological analysis. RESULTS: The plasma triglycerides (2.5–3 fold), total cholesterol (4–5 fold) and LDL levels (35–40 fold) of ApoE−/− dogs were higher than those of the wild-type and ApoE-/+ dogs. Compared with the wild-type and young ApoE-/+ dogs, the IMT of CCA and aorta in ApoE−/− dogs were increased (p<0.05). The occurrence of atherosclerosis in ApoE−/− dogs was higher than that in ApoE-/+ dogs (50% vs. 10.3%, p=0.013) and the occurrence time was earlier. Histology confirmed that the aorta, carotid arteries and CIA had atherosclerotic lesions in ApoE−/− dogs. CONCLUSIONS: The ApoE-deficient dogs were a reliable animal model of atherosclerosis. VDU is an optimal in vivo noninvasive method for evaluating atherosclerosis phenotypes in large animal models.