title: Expression of periodontal interleukin-6 protein is increased across patients with neither periodontal disease nor diabetes, patients with periodontal disease alone and patients with both diseases.
abstract: OBJECTIVE
  Epidemiological studies have established that patients with diabetes have an increased prevalence and severity of periodontal disease. Interleukin (IL)-6, a multifunctional cytokine, plays a role in the tissue inflammation that characterizes periodontal disease. Our recent study has shown a trend of increase in periodontal IL-6 expression at the mRNA level across patients with neither periodontal disease nor diabetes, patients with periodontal disease alone and patients with both diseases. However, the periodontal IL-6 expression at the protein level in these patients has not been investigated.
  
  
  METHODS
  Periodontal tissue specimens were collected from eight patients without periodontal disease and diabetes (group 1), from 17 patients with periodontal disease alone (group 2) and from 10 patients with both periodontal disease and diabetes (group 3). The frozen sections were prepared from these tissue specimens and IL-6 protein expression was detected and quantified.
  
  
  RESULTS
  The nonparametric Kruskal-Wallis test showed that the difference in IL-6 protein levels among the three groups was statistically significant (p = 0.035). Nonparametric analysis using the Jonckheere-Terpstra test showed a tendency of increase in periodontal IL-6 protein levels across group 1 to group 2 to group 3 (p = 0.006). Parametric analysis of variance (ANOVA) on IL-6 protein levels showed that neither age nor gender significantly affected the difference of IL-6 levels among the groups.
  
  
  CONCLUSIONS
  Periodontal IL-6 expression at the protein level is increased across patients with neither periodontal disease nor diabetes, patients with periodontal disease alone and patients with both diseases.
authors.affiliation: Division of Periodontics, Department of Stomatology, College of Dental Medicine, Medical University of South Carolina, Charleston, SC, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Ross
authors.forename: D C
authors.initials: DC
authors.lastname: Hardy
authors.forename: C A
authors.initials: CA
authors.lastname: Schuyler
authors.forename: E H
authors.initials: EH
authors.lastname: Slate
authors.forename: T W
authors.initials: TW
authors.lastname: Mize
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D048909:Diabetes Complications / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005260:Female; D015870:Gene Expression; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007124:Immunoenzyme Techniques; D015850:Interleukin-6 / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010510:Periodontal Diseases / Q000150:complications / Q000378:metabolism*; D010519:Periodontium / Q000378:metabolism; D018709:Statistics, Nonparametric
chemical_list: D015850:Interleukin-6