Experimental study of the mechanism that smoking can cause aneurismal change in the aorta

2007 Fiscal Year Final Research Report Summary

• Project/Area Number: 17591454
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Thoracic surgery
• Research Institution: Tohoku University
• Principal Investigator: SAIKI Yoshikatsu Tohoku University, Tohoku University Hospital, Lecturer (50372298)
• Co-Investigator(Kenkyū-buntansha): TABAYASHI Koichi Graduate School of Medicine, 大学院・医学系研究科, Professor (90142942) ; IGUCHI Atsushi Graduate School of Medicine, 大学院・医学系研究科, Associate Professor (90222851) ; ODA Katsuhiko Graduate School of Medicine, 大学院・医学系研究科, Assistant Professor (60323002) ; AKASAKA Junetsu Tohoku University Hospital, 病院, Assistant Professor (80343044) ; NITTA Yoshio Tohoku University Hospital, 病院, Assistant Professor (80375005)
• Project Period (FY): 2005 – 2007
• Keywords: Smoking / Aortic aneurysm / Drug delivery system

Research Abstract

The heavy smokers have more potential risk of enlargement of aortic wall than non-smoker etiologically. Thus our purpose is to analyze the mechanism that smoking can cause aneurismal change in the aorta by using drug delivery system. Our hypothesis is that chemical agents from cigarette can cause wall destruction in the vessel wall. We prepared 50mg of the PLCL film containing benzopyrene (0.7, 7, 70mg, respectively). We used 6 beagles as animal models. Under general anesthesia, left lateral thoracotomy was done. The thoracic descending aorta was exposed. The PLCL film containing benzopyrene was attached to the aortic wall directly. After one month, the dogs were sacrificed and the thoracic descending aorta was excised. There was tight adhesion between the aortic wall and the lung macroscopically. The histological findings revealed that the fundamental construction of vessel wall (adventitia, media, and intima) was maintained. The thinning of fibrous tissue was not observed. Neutrophil infiltration to the wall tissue was markedly observed, thus severe inflammation may be caused by benzopyrene. We confirmed the fact repeatedly. The exposure of benzopyrene from outer surface of the aorta is not physiological. Intramural thrombus was located at intima. The exposure of benzopyrene from inner surface may cause wall destruction. Further analysis will be needed in the relationship between smoking and aneurysmal change of the aortic wall.