title: Smoking modulates interleukin-6:interleukin-10 and RANKL:osteoprotegerin ratios in the periodontal tissues.
abstract: OBJECTIVE
  This study evaluated the effect of smoking on the gene expression of interleukin-1alpha, -1ra, -6, -8 and -10, tumor necrosis factor-alpha, matrix metalloproteinase (MMP)-2 and -8, receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin, in sites with periodontitis.
  
  
  METHODS
  Gingival biopsies were divided into three groups: the healthy group (periodontally healthy subjects; n=10); the periodontitis group [subjects with severe chronic periodontitis who never smoked (probing depth>or=7 mm) (n=25)]; and the smoking group (subjects diagnosed with severe chronic periodontitis who smoked>or=1 pack per day for at least 10 years; n=25). Gene and protein expressions were analyzed by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively.
  
  
  RESULTS
  Data analysis demonstrated that, except for MMP-8 and osteoprotegerin, the levels of all factors were increased by inflammation (p<0.001). The levels of interleukin-1alpha, -1ra, -6 and -8, and RANKL, were higher in smokers with periodontitis compared with controls, whereas the levels of interleukin-10, MMP-8 and osteoprotegerin were lower (p<0.001). Smoking lowered the levels of interleukin-1alpha, -8, -10, tumor necrosis factor-alpha, MMP-8 and osteoprotegerin, and increased the levels of interleukin-6 and -1ra in sites with a comparable type of periodontitis (p<0.001).
  
  
  CONCLUSIONS
  In conclusion, smoking modulates gene expression in the periodontium, and the influence of smoking on periodontal disease may involve effects of interleukin-6:interleukin-10 and RANKL:osteoprotegerin ratios.
authors.affiliation: Department of Prosthodontics/Periodontics, Division of Periodontics, School of Dentistry at Piracicaba, University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: J B
authors.initials: JB
authors.lastname: César-Neto
authors.forename: P M
authors.initials: PM
authors.lastname: Duarte
authors.forename: M C G
authors.initials: MC
authors.lastname: de Oliveira
authors.forename: C H
authors.initials: CH
authors.lastname: Tambeli
authors.forename: E A
authors.initials: EA
authors.lastname: Sallum
authors.forename: F H
authors.initials: FH
authors.lastname: Nociti
mesh_terms: D000704:Analysis of Variance; D016022:Case-Control Studies; D002908:Chronic Disease; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015870:Gene Expression; D006801:Humans; D007378:Interleukins / Q000096:biosynthesis*; D008297:Male; D020782:Matrix Metalloproteinases / Q000096:biosynthesis; D053244:Osteoprotegerin / Q000096:biosynthesis*; D010518:Periodontitis / Q000209:etiology / Q000378:metabolism*; D053245:RANK Ligand / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012907:Smoking / Q000009:adverse effects*; D018709:Statistics, Nonparametric; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D007378:Interleukins; D053244:Osteoprotegerin; D053245:RANK Ligand; D014409:Tumor Necrosis Factor-alpha; D020782:Matrix Metalloproteinases