Hypothesis: Rheumatoid arthritis and periodontitis: A new possible link via prolactin hormone.

Rheumatoid arthritis and periodontitis are two common chronic inflammatory diseases affecting human population worldwide. The association between the two conditions have been the focus of many researches, trying to explore the possible mechanisms underlying this association. Prolactin hormone, besides its known lactogenic effects acts as a cytokine secreted from various tissues other than the pituitary gland with multiple pleotropic actions in immunity and inflammation. Several data showed that prolactin levels are increased significantly in the synovial and periodontal tissues, and this increase is correlated with disease activity and tissue destruction. Our hypothesis suggests that local prolactin can represent a link between the two conditions. In this work, we suggest a possible mechanistic interactions, hypothesized to form a common path linking between rheumatoid arthritis, periodontitis and prolactin. This is because of the need to develop new treatment strategies for the most effective long term control of inflammation in both conditions.