Is Adrenomedullin Upregulation Due to Apical Periodontitis Independent of Periodontal Disease?

Bone destruction in apical periodontitis (AP) depends on the microorganisms' efficiency to breach the host-epithelial barrier and various antimicrobial peptides. Mid-regional pro adrenomedullin (MR-proADM) is one such potent antimicrobial peptide, which plays a regulatory and stabilizing role among proinflammatory and anti-inflammatory cytokines. A broad range of cells and tissues produce MR-proADM such as adrenal medulla, kidney, lungs, and endothelial cells. MR-proADM was found to be present in circulation and in various biological fluids. It is reported to function both as a generalized hormone and locally affecting autocrine or paracrine mediator. Its plasma level is usually elevated in certain conditions such as heart failure, hypertensive situations, cerebro-vascular events, chronic kidney failure, diabetes mellitus, sepsis and periodontitis. Besides these, MR-proADM has drawn attention as it stimulates the proinflammatory cytokine IL-6 and suppresses cytokines, like TNF- α, for regulating inflammation, being a potent of inhibitor of apoptosis and stimulating angiogenesis in tumor cells. However, there is still a large information gap on MR-proADM. Despite all these effects, there is not enough information in the literature about the effect of MR-proADM on oral and dental health and its effectiveness in apical periodontitis. Whether AP can cause any alterations in the MR-proADM value is also unknown.

Therefore, the aim of this study is to investigate the relationship between AP severity and inflammatory markers (IL-12, TNF-alpha), and MR-proADM in patients with AP. In addition, the results will be compared with the results of healthy controls and patients with chronic periodontitis.