Vascular diseases such as atherosclerosis and aneurysms are associated with diet. Perivascular adipose tissue (PVAT) was reportedly involved in the regulation of vascular functions. It is suggested that imbalanced diets can cause PVAT inflammation and dysfunction as well as impaired vascular function. However, the association between diets and PVAT are not clearly understood. Here, we showed that a high-fat and a high-sucrose diet affected PVAT at different sites. A high-fat diet induced increased number of large-sized lipid droplets and increased CD (Cluster of differentiation) 68+ macrophage- and monocyte chemotactic protein (MCP)-1-positive areas in the abdominal aortic PVAT (aPVAT). In addition, a high-fat diet caused decreased collagen fibre-positive area and increased CD68+ macrophage- and MCP-1-positive areas in the abdominal aorta. In contrast, a high-sucrose diet induced increased number of large-sized lipid droplets, increased CD68+ macrophage- and MCP-1-positive areas, and decreased UCP-1 positive area in the thoracic aortic PVAT (tPVAT). A high-sucrose diet caused decreased collagen fibre-positive area and increased CD68+ macrophage- and MCP-1-positive areas in the thoracic aorta. These results could be attributed to the different adipocyte populations in the tPVAT and aPVAT. Our results provide pathological evidence to improve our understanding of the relationship between diet and vascular diseases.

Introduction Abdominal aortic aneurysm AAA , characterized as a chronic inflammation of the vascular wall coupled with progressive abdominal aorta distention, is considered to be associated with age, male sex, smoking and hypertension. AAA is responsible for high death rates due to ruptures caused by AAA 1. At present, pharmacological treatments for AAA development and rupture are not available. AAA leads to infiltration of the vascular wall by inflammatory cells, such as lymphocytes and macrophages, resulting in the release of inflammatory mediators and free radicals as well as a loss of elastin and collagen in the media and adventitia due to matrix metalloproteinases MMPs , all of which contribute to a reduction in vascular wall strength 2. Cigarette smoking has been linked to deaths caused by cardiovascular dysfunction worldwide 3. Cigarette smoking, in particular, is a primary risk factor for AAA and a major cause of death from cardiovascular disease globally 3, 4. Nic