title: Mast cells modulate the pathogenesis of elastase-induced abdominal aortic aneurysms in mice.
abstract: Abdominal aortic aneurysm (AAA), an inflammatory disease, involves leukocyte recruitment, immune responses, inflammatory cytokine production, vascular remodeling, neovascularization, and vascular cell apoptosis, all of which contribute to aortic dilatation. This study demonstrates that mast cells, key participants in human allergic immunity, participate in AAA pathogenesis in mice. Mast cells were found to accumulate in murine AAA lesions. Mast cell-deficient KitW-sh/KitW-sh mice failed to develop AAA elicited by elastase perfusion or periaortic chemical injury. KitW-sh/KitW-sh mice had reduced aortic expansion and internal elastic lamina degradation; decreased numbers of macrophages, CD3+ T lymphocytes, SMCs, apoptotic cells, and CD31+ microvessels; and decreased levels of aortic tissue IL-6 and IFN-gamma. Activation of mast cells in WT mice via C48/80 injection resulted in enhanced AAA growth while mast cell stabilization with disodium cromoglycate diminished AAA formation. Mechanistic studies demonstrated that mast cells participated in angiogenesis, aortic SMC apoptosis, and matrix-degrading protease expression. Reconstitution of KitW-sh/KitW-sh mice with bone marrow-derived mast cells from WT or TNF-alpha-/- mice, but not from IL-6-/- or IFN-gamma-/- mice, caused susceptibility to AAA formation to be regained. These results demonstrate that mast cells participate in AAA pathogenesis in mice by releasing proinflammatory cytokines IL-6 and IFN-gamma, which may induce aortic SMC apoptosis, matrix-degrading protease expression, and vascular wall remodeling, important hallmarks of arterial aneurysms.
authors.affiliation: Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: Jiusong
authors.initials: J
authors.lastname: Sun
authors.forename: Galina K
authors.initials: GK
authors.lastname: Sukhova
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Wolters
authors.forename: Lindsey A
authors.initials: LA
authors.lastname: MacFarlane
authors.forename: Peter
authors.initials: P
authors.lastname: Libby
authors.forename: Chongxiu
authors.initials: C
authors.lastname: Sun
authors.forename: Yadong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.forename: Terri L
authors.initials: TL
authors.lastname: Ennis
authors.forename: Rebecca
authors.initials: R
authors.lastname: Knispel
authors.forename: Wanfen
authors.initials: W
authors.lastname: Xiong
authors.forename: Robert W
authors.initials: RW
authors.lastname: Thompson
authors.forename: B Timothy
authors.initials: BT
authors.lastname: Baxter
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Shi
mesh_terms: D000818:Animals; D001011:Aorta / Q000033:anatomy & histology / Q000378:metabolism / Q000473:pathology; D017544:Aortic Aneurysm, Abdominal / Q000139:chemically induced* / Q000276:immunology / Q000473:pathology; D004549:Elastin / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000166:cytology / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010196:Pancreatic Elastase / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
chemical_list: D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma; D004549:Elastin; D019009:Proto-Oncogene Proteins c-kit; D010196:Pancreatic Elastase