Effects of hypercholesterolism on expansion of abdominal aortic aneurysm in rat model

Abstract

Background Inflammation is recognized as a critical process in expansion of abdominal aortic aneurysm (AAA). A relationship between effects of cholesterol and statin in this process have been suggested, but remain untested. Therefore, current study aimed to examine the effects of hypercholesterolism on expansion of AAA in a rat model. Methods A total of 16 male rats were divided into 4 groups as follows: group I, normocholesterol diet and saline infusion, group II, normocholesterol diet and porcine pancreatic elastase (PPE) infusion, group III, hypercholesterol diet and PPE infusion, and group IV, hypercholesterol diet, PPE infusion and statin administration. At the 3rd week, saline was infused intraluminally in group I and PPE in groups II-IV to induce AAA. At the 5th week, blood and aortic tissue were obtained from each rat for evaluation of lipid profiles, aortic diameters (ADs), and characteristics of stains. Results Post-procedural aortic diameter (AD3) and AD3/pre-procedural aortic diameter (AD1) were significantly different among four groups (P = 0.042, P = 0.028, respectively). AD3 was significantly larger in group II than group I, and group III than group IV (P = 0.012, P = 0.043, respectively). AD3/AD1 was significantly higher in group II than group I, and group III than group II (P = 0.008, P = 0.030, respectively). Group III showed the highest cellularity for inflammatory cells. Conclusions Though larger experimental and clinical studies are necessary, authors suggest that hypercholesterolism can aggravate expansion of AAA, and that statin therapy can reduce it. Therefore, monitoring for hypercholesterolism and instituting statin therapy may be helpful to suppress expansion of AAA.