title: Arterial inflammation in mice lacking the interleukin 1 receptor antagonist gene.
abstract: Branch points and flexures in the high pressure arterial system have long been recognized as sites of unusually high turbulence and consequent stress in humans are foci for atherosclerotic lesions. We show that mice that are homozygous for a null mutation in the gene encoding an endogenous antiinflammatory cytokine, interleukin 1 receptor antagonist (IL-1ra), develop lethal arterial inflammation involving branch points and flexures of the aorta and its primary and secondary branches. We observe massive transmural infiltration of neutrophils, macrophages, and CD4(+) T cells. Animals appear to die from vessel wall collapse, stenosis, and organ infarction or from hemorrhage from ruptured aneurysms. Heterozygotes do not die from arteritis within a year of birth but do develop small lesions, which suggests that a reduced level of IL-1ra is insufficient to fully control inflammation in arteries. Our results demonstrate a surprisingly specific role for IL-1ra in the control of spontaneous inflammation in constitutively stressed artery walls, suggesting that expression of IL-1 is likely to have a significant role in signaling artery wall damage.
authors.affiliation: Division of Molecular and Genetic Medicine, University of Sheffield, Royal Hallamshire Hospital, Sheffield S10 2JF, United Kingdom. m.nicklin@sheffield.ac.uk
authors.forename: M J
authors.initials: MJ
authors.lastname: Nicklin
authors.forename: D E
authors.initials: DE
authors.lastname: Hughes
authors.forename: J L
authors.initials: JL
authors.lastname: Barton
authors.forename: J M
authors.initials: JM
authors.lastname: Ure
authors.forename: G W
authors.initials: GW
authors.lastname: Duff
mesh_terms: D017668:Age of Onset; D000483:Alleles; D000818:Animals; D001167:Arteritis / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D005260:Female; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein; D008136:Longevity; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017472:Receptors, Interleukin-1 / Q000032:analysis / Q000037:antagonists & inhibitors*; D012795:Sialoglycoproteins / Q000235:genetics* / Q000276:immunology
chemical_list: C507763:IL1RN protein, human; C507764:Il1rn protein, mouse; D053590:Interleukin 1 Receptor Antagonist Protein; D017472:Receptors, Interleukin-1; D012795:Sialoglycoproteins