title: Balance of interleukin-1 beta and interleukin-1 receptor antagonist in human periapical lesions.
abstract: Interleukin-1 beta (IL-1 beta) has been considered as a major potent mediator of bone resorption and implicated in the development of human periapical lesions. Among naturally occurring interleukin-1 (IL-1) inhibitors, IL-1 receptor antagonist (IL-1ra) is a 22 kDa protein that shares homology with IL-1 beta and IL-1 alpha, binds to IL-1 receptor with similar affinity to IL-1, and has no known agonist properties. In this study, we measured the periapical exudate (PE) levels of IL-1 beta and IL-1ra from human periapical lesions. PE samples were collected from root canals during routine endodontic treatments, and the enzyme-linked immunosorbent assay was used to measure PE-IL-1 beta and IL-1ra. Detectable levels of both IL-1 beta and IL-1ra were found in 25 of 29 clinical samples. Relatively high levels of IL-1ra compared with IL-1 beta (mean IL-1ra:IL-1 beta ratio = 128:7; range: 0.9 to 495.4), and significantly positive correlation between IL-1ra and IL-1 beta levels was found. The PE-IL-1ra:IL-1 beta ratios obtained from symptomatic lesions were significantly lower than those from asymptomatic lesions. These results suggest that IL-1ra-mediated IL-1 antagonism occurred to block locally produced IL-1 activity, and the balance of IL-1 to IL-1ra production may be crucial in the development of periapical lesions.
authors.affiliation: Department of Periodontology and Endodontology, Osaka University Faculty of Dentistry, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shimauchi
authors.forename: S
authors.initials: S
authors.lastname: Takayama
authors.forename: T
authors.initials: T
authors.lastname: Imai-Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Okada
mesh_terms: D000704:Analysis of Variance; D015536:Down-Regulation; D005122:Exudates and Transudates; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D010482:Periapical Abscess / Q000276:immunology / Q000378:metabolism*; D011379:Prognosis; D012795:Sialoglycoproteins / Q000276:immunology / Q000378:metabolism*; D018709:Statistics, Nonparametric
chemical_list: C507763:IL1RN protein, human; D018836:Inflammation Mediators; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D012795:Sialoglycoproteins