Introduction
inflammation, RA, periodontitis, teeth loss
RHEUMATIC DISEASES, INFLAMMATION, PERIODONTITIS, RECRUITMENT, PITUITARY, PERIODONTITIS
Hormones are involved in various aspects of the immune response and rheumatic diseases; the interest in the crosstalk between hormones and cytokines acting on inflammation and bone metabolism has recently grown [Periodontitis (P) is another chronic inflammatory disease of teeth supporting structures, mainly induced by bacterial biofilm dysbiosis with a multifactorial contribution. Bacteria-derived factors stimulate a local inflammatory reaction, cytokines release, followed by recruitment and activation of T and B lymphocytes causing periodontal tissue destruction and teeth loss. Treatment of periodontitis aims mainly at reduction of microbial load and associated inflammation by mechanical debridement. However, due to the multifactorial nature of periodontitis, standard treatment may not be a sufficient to achieve long-term clinical improvements [Since the association between periodontitis and RA has been confirmed long ago by almost all the population‐based studies, now, there is a need to investigate possible mechanisms that might be responsible for such an association [Prolactin (PRL) is a neuroendocrine hormone that mainly regulates lactation; however, it also acts as a cytokine with both autocrine, endocrine, and paracrine effects. PRL is mainly secreted by pituitary gland besides many extra-pituitary tissues and cells. Pituitary and extra-pituitary released PRL are structurally identical and bind to the same receptors that are expressed in the pituitary as well as many other tissue cells including the heart, immune system cells, and osteoblasts. Regulation of extra-pituitary PRL is mainly site specific and independent from pituitary PRL [Rahajoe et al. stated that “analysis of gingival crevicular fluid of RA patients reveals that the relationship between periodontitis and RA is bidirectional, and studying cytokines in the periodontal inflammatory exudate of RA patients might provide insight into the association between periodontitis and RA” [