Are periodontitis and psoriasis associated? A pre-clinical murine model

Aim: To investigate the bidirectional influence between periodontitis and psoriasis, using the respective experimental models of ligature- and imiquimod-induced diseases on murine models. Materials and Methods: Thirty-two C57/BL6J mice were randomly allocated to four experimental groups: control (P- Pso-), ligature-induced periodontitis (P+ Pso-), imiquimod-induced psoriasis (P- Pso+) and periodontitis and psoriasis (P+ Pso+). Samples (maxilla, dorsal skin and blood) were harvested immediately after death. Measures of periodontitis (distance between the cemento-enamel junction and alveolar bone crest [CEJ-ABC] and the number of osteoclasts) and psoriasis (epidermal thickness and infiltrate cell [/0.03mm(2)]) severity as well as systemic inflammation (IL-6, IL-17A, TNF-alpha) were collected. Results: The P+ Pso+ group exhibited the most severe experimental periodontitis and psoriasis, with the highest values of CEJ-ABC, number of osteoclasts, epidermal thickness and infiltrate cells in the dorsal skin, as well as the highest blood cytokine concentration. The P+ Pso- group presented with higher cell infiltrate (/0.03mm(2)) compared to the control group (p <.05), while the P- Pso+ group showed substantially higher alveolar bone loss (CEJ-ABC) than the control group (p <.05). Conclusions: Experimental periodontitis may initiate and maintain psoriasiform skin inflammation and, vice versa, experimental psoriasis may contribute to the onset of periodontitis. In a combined model of the diseases, we propose a bidirectional association between periodontitis and psoriasis via systemic inflammation.