title: Enhanced tumor necrosis factor- alpha expression in small sized abdominal aortic aneurysms.
abstract: Circulating levels of tumor necrosis factor alpha (TNF- alpha) are elevated in the patients with abdominal aortic aneurysm (AAA). We investigated TNF- alpha expression and cellular infiltration in the walls of AAAs of different sizes. Twenty-seven surgical specimens of AAAs were categorized according to the maximum aneurysm diameter into a small size group (less than 50 mm in diameter, n = 8; S group), a medium-sized group (50 to 59 mm in diameter, n = 11; M group), and a large size group (larger than 59 mm in diameter, n = 8; L group). The level of TNF- alpha and interleukin-1 beta(IL-1 beta) in the aneurysm wall was measured by ELISA. Immunohistochemical staining was performed to observe the TNF- alpha expression and the infiltration of macrophages and lymphocytes in aneurysm walls. Enzyme-linked immunosorbent assay showed that the level of TNF- alpha in the S group (5.47 +/- 3.48 pg/mg protein) was significantly higher ( p < 0.05) than that in the M group (2.70 +/- 1.33 pg/mg protein) or the L group (1.82 +/- 1.21 pg/mg protein). No significant difference in IL-1 beta was observed between the S, M, and L groups. Immunohistochemical analysis also showed that TNF- alpha was expressed strongly in the S group but was negative or weakly positive in the M and L groups. Furthermore, the expression of TNF- alpha was seen mainly where the aneurysm wall showed atheromatous change and macrophage infiltration. These results indicated that the expression of TNF- alpha in the aneurysm wall was enhanced in small AAAs, and this enhancement might be related to the infiltration of macrophages.
authors.affiliation: First Department of Surgery, Yamaguchi University School of Medicine, 1-1-1 Minami-kogushi, Ube, 755-8505, Yamaguchi, Japan.
authors.forename: Kimikazu
authors.initials: K
authors.lastname: Hamano
authors.forename: Tao-Sheng
authors.initials: TS
authors.lastname: Li
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Takahashi
authors.forename: Toshiro
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Bungo
authors.initials: B
authors.lastname: Shirasawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Nobuya
authors.initials: N
authors.lastname: Zempo
mesh_terms: D001012:Aorta, Abdominal / Q000737:chemistry; D017544:Aortic Aneurysm, Abdominal / Q000276:immunology* / Q000378:metabolism* / Q000503:physiopathology; D046508:Culture Techniques; D006801:Humans; D008264:Macrophages / Q000276:immunology*; D009131:Muscle, Smooth, Vascular / Q000737:chemistry; D013601:T-Lymphocytes / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000378:metabolism*
chemical_list: D014409:Tumor Necrosis Factor-alpha