Differential circulating levels of HSP-27 in chronic and aggressive periodontitis

Abstract

Objectives: Heat-shock protein (Hsp) 27 is a major intracellular molecular chaperone and controller of intracellular responses to inflammatory signals. Recombinant Hsp27 is also able to modulate myeloid cell activity with the protein showing an anti-inflammatory mode of action in vitro. The aim of this study was to assess a potential role of circulating levels of Hsp27 in periodontitis. Methods: Pro- and anti-inflammatory cytokines as well as stress proteins Hsp27 and Hsp60 with anti- and pro-inflammatory properties, respectively, were measured by two-site ELISA in the serum of patients with Chronic periodontitis (CP, n=29), Aggressive Periodontitis (AgP, n=30) and periodontally healthy controls (H, n=28). Furthermore, Hsp27 and Hsp60 levels were also measured longitudinally in 12 AgP patients at 6 time-points after treatment (from baseline to 3-months after treatment). Results: AgP patients had lower levels of Hsp27 compared with CP and H subjects (adjusted one-way ANOVA p<0.001, followed by post-hoc Tukey HSD comparisons), while no difference in levels of cytokines or Hsp60 between the three groups, and in Hsp27 levels in healthy individuals or in chronic periodontitis patients were detected. A positive correlation was detected between Hsp27 levels and Hsp60 (r=0.49, p<0.001) and IL-6 levels (r=0.354, p<0.001). No consistent patterns of changes in Hsp27 circulating levels were detected following treatment of AgP cases. Conclusions: Circulating Hsp27 levels were associated with other cytokines levels, confirming its possible involvement in the periodontal inflammatory process. This study shows for the first time lower circulating Hsp27 in AgP patients, suggesting that this heat-shock protein may be differentially expressed in aggressive and chronic periodontitis.