Site-Specific Atherogenic Gene Expression Correlates With Subsequent Variable Lesion Development in Coronary and Peripheral Vasculature

Abstract

Objectives-The relationship between specific gene regulation and subsequent development and progression of atherosclerosis is incompletely understood. We hypothesized that genes in the vasculature related to cholesterol metabolism, inflammation, and insulin signaling pathways are differentially regulated in a site-specific and time-dependent manner. Methods and Results-Expression of 59 genes obtained from coronary, carotid, and thoracic aortic arteries were characterized from diabetic (DM)/hypercholesterolemic (HC) swine (nϭ52) 1, 3, and 6 months after induction. Lesion development in the 3 arterial beds was quantified and characterized at 1, 3, 6, and 9 months. Progressive lesion development was observed in the coronaryϾthoracic aortaϾ Ͼcarotid arteries. Genes involved in cholesterol metabolism and insulin pathways were upregulated in coronariesϾthoracic aortaeϾcarotids. Inflammatory genes were more markedly upregulated in coronary arteries than the other 2 arteries. Genes implicated in plaque instability (eg, matrix metalloproteinase-9, CCL2 and Lp-PLA 2 mRNAs) were only upregulated at 6 months in coronary arteries. Key Words: atherosclerosis Ⅲ diabetes Ⅲ hypercholesterolemia Ⅲ animal models Ⅲ mRNA A therosclerosis is a multi-factorial pathological process resulting from environmental and genetic influences involving multiple vascular territories. Patients with diabetes mellitus (DM) have an increased risk of developing accelerated cardiovascular disease which is potentiated by hypercholesterolemia (HC). 1 Although gene expression of atherosclerotic genes is associated with the presence of atherosclerosis, the sequence of specific gene regulation and the relationship to subsequent development of atherosclerosis is incompletely understood. Also unclear is whether development of atherosclerosis in separate vascular beds is associated with differential gene expression. Conclusions-VariableWe hypothesized that genes relating to vascular cholesterol metabolism, insulin pathways, and inflammatory responses are differentially regulated in a site-specific and time-dependent manner. We tested this hypothesis in the atherosclerotic DM/HC swine model which develops advanced coronary lesions within 6 months. 2 We chose genes that had previously (1) shown differential expression in stable and unstable human atherosclerotic plaques, (2) demonstrated involvement in the atherosclerotic process, and (3) had a pig ortholog. 3 MethodsDiabetes mellitus was induced in male pigs (nϭ52) weighing 25 to 30 kg by 125 mg/kg of intravenous streptozotocin (Sicor Pharmaceuticals). Exogenous insulin was administered to insure that glucose levels did not exceed 350 mg/dL. The animals were fed chow containing 0.5% to 2% cholesterol, 5% to 20% lard, and 1.5% sodium cholate (Animal Specialties) to achieve a cholesterol level of 250 to 1000 mg/dL. Animals were euthanized at 1, 3, 6, or 9 months after induction. The protocol followed institutional guidelines. Histological EvaluationPlease see supplemental methods, available online at http://atvb....

Coronary microvascular dysfunction in a porcine model of early atherosclerosis and diabetes

“…Also, atherosclerotic DM porcine models have been developed and successfully employed (16,17,23,37,41,63). However, limited data on coronary endothelial function are available from these DM models and usually only in the presence of advanced CAD.…”

“…Therefore, suitable animal models focusing on early disease development are necessary. Because of the highly similar anatomy and physiology of the cardiovascular system, porcine models with toxin-mediated pancreatic damage in combination with an atherogenic diet have been previously used to study DM and cardiovascular complications (16,17,23,37,41,42,63). However, most of these models have focused on advanced CAD with clear presence of atherosclerotic plaque.…”

Vascular Responses to Drug-Eluting and Bare Metal Stents in Diabetic/Hypercholesterolemic and Nonatherosclerotic Porcine Coronary Arteries

“…6 Lesion development and progression is dependent in large part on vascular inflammation associated with increased expression of numerous proinflammatory genes, many crucial for macrophage and T-lymphocyte recruitment and functioning and subsequent upregulation of inflammatory mediators. 6,7,13,14 Furthermore, DM and HC synergistically result in hypoactivation of the Akt pathway, resulting in increased cellular proliferation, apoptosis, vasa vasorum neovascularization, inflammation, and advanced atherosclerosis. 14 Such lipid-rich atheroma, in the setting of increased numbers of macrophages and T-lymphocytes, reflect increased oxidative stress that mimics human diabetic lesions.…”

“…Results of the incidence, severity, and morphometric characteristics of coronary lesions of this group have been previously published. 6 The 2 intervention studies used a similar protocol for stent implantation, and in both studies, a single stent was implanted in 1 coronary artery (see below). Twenty pigs were enrolled in the DM/HC intervention, 21 pigs in the DM/HC no intervention group, and 20 in the non-DM/HC intervention study.…”

“…The current study was designed to evaluate the differential vascular responses to stent implantation, either paclitaxeleluting stents (PES) or bare metal stents (BMS), in a porcine model of complex coronary atherosclerosis [5][6][7] compared with responses in a standard pig model.…”