The Role of Inflammatory Cytokines in the Bidirectional Relationship between Periodontitis and Diabetes Mellitus

Periodontitis and type 2 diabetes mellitus are associated with each other in a bidirectional relationship. The mechanism by which diabetes affects periodontitis is understood to be due to the inflammatory effects of hyperglycemia (high blood glucose levels) and a hospitable environment for sugar-consuming bacteria. Periodontitis is known to be associated with higher levels of glycated hemoglobin (HbA1c), a long-term measurement of blood glucose control, and treatment of periodontitis reduces HbA1c. Inflammation caused by periodontitis induces insulin resistance (which leads to higher blood glucose levels), but due to the complex nature of inflammation it is difficult to single out one specific cause and effect relationship. Tumor necrosis factor-alpha (TNF-α) is a cytokine produced by macrophages and monocytes during acute inflammation. TNF-α is of interest due to its association with the disruption of insulin receptors in skeletal muscle cells and dysfunction of the pancreatic β-cells that produce insulin and is found to be elevated in patients with periodontitis. Treatment of periodontitis reduces the burden of inflammation on the body’s metabolic controls to improve control of blood glucose levels. Thus, oral health care is associated with general healthcare to provide better outcomes and supplemental treatments to improve patient conditions at the margin.