Exploring Apelin Dynamics in Serum and Saliva: A Link BetweenPeriodontitis, Obesity, and Diabetes

Introduction: Periodontitis is an inflammatory, destructive condition influenced by obesity and Type 2 Diabetes Mellitus (T2DM), among other etiological factors. Apelin, a bioactive peptide, is linked to periodontitis, obesity, and T2DM. This study aimed to investigate apelin levels in individuals with periodontitis affected by obesity and T2DM. Methods: This cross-sectional observational study included 84 participants categorized into three main groups based on their periodontal status, Body Mass Index (BMI), and Glycated Haemoglobin (HbA1c), subcategorized into A (with CP) and B (without CP), each group containing 14 participants. Group I consisted of participants with and without Chronic Periodontitis (CP), Group II consisted of obese individuals with and without CP, and Group III consisted of obese individuals with T2DM, with and without CP. Parameters assessed: Sulcus Bleeding Index (SBI), BMI, HbA1c, Probing Pocket Depth (PPD), and Clinical Attachment Level (CAL). Apelin (APLN) levels in Serum (SER) and Saliva (SAL) were quantified using Enzyme-Linked Immunosorbent Assay (ELISA). Data was analyzed with ANOVA. Results: Individuals with periodontitis had lower SER and SALry APLN levels than those without periodontitis. Furthermore, the study found that overweight individuals, as well as those with T2DM and obesity, had even higher levels of APLN than systemically healthy individuals. Discussion: It has been proposed that diabetes worsens the inflammatory response to plaque buildup through various mechanisms. Periodontal disease can affect fat metabolism by elevating cytokine levels, which induce inflammatory changes in adipose tissue. This results in increased secretion of adipokines, which impairs glycemic control and increases the expression of Advanced Glycation End products (AGEs). These AGEs further impact periodontal inflammation by increasing cytokine production, thereby depicting a bidirectional relationship between the two conditions. Conclusion: This study demonstrates that APLN could be a valuable biomarker for evaluating periodontal disease in patients with obesity and T2DM. However, further longitudinal research with a significant sample size is needed to confirm the results of this study and clarify the role and function of APLN in periodontitis, obesity, and T2DM.