Investigation of IRS-2 and SOD-1 as biomarkers of homeostasis of glycemic and oxidative metabolism in patients with type 2 diabetes mellitus and periodontitis undergoing periodontal treatment

• Grant number: 22/11382-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2023
• End date: February 29, 2024
• Field of knowledge: Health Sciences - Dentistry - Periodontology
• Principal Investigator: Raquel Mantuaneli Scarel Caminaga
• Grantee: Francois Isnaldo Dias Caldeira
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

The incidence of patients affected simultaneously by Type 2 Diabetes Mellitus (T2DM), Dyslipidemia and Periodontitis (P) is increasing. Also increases the evidence in the literature demonstrating interactions among these pathologies, mediated by immune system dysfunction and higher glyco-oxidative stress. In order to contribute, our research group is developing the project "Morpho-functional evaluation of PPARG and IL7 as key molecules for glycemic and immunological alterations in Type 2 Diabetes Mellitus and Periodontitis" (FAPESP Grant 2020/12788-5). We also have results from the salivary proteome that was performed with 150 patients affected by different combinations of the aforementioned pathologies. One of the most interesting proteins that was identified as over-expressed and exclusive in the saliva of individuals simultaneously affected by T2DM_Compensated+Dyslipidemia+P was the IRS-2 (Insulin Receptor Substrate 2). Tumor necrosis factor alpha (TNF-±) induces increased phosphorylation of serine residues of IRS-1 disrupting the insulin signaling cascade, i.e., leading to insulin resistance. The overproduction of ROS (reactive oxygen species) is an important trigger for insulin resistance and development of T2DM; besides that, ROS are also involved in the pathogenesis of periodontitis. The overproduction of ROS in T2DM and P may be induced by TNF-±. One of the key antioxidant enzymes for controlling the glyco-oxidative stress that occurs in T2DM is Superoxide Dismutase 1 (SOD-1). We verified by Bioinformatics the indirect interaction of IRS-2 and SOD-1, which occurs through TNF-±. Our proteome results suggest that IRS-2 over-expression contributes to the achievement of glycemic control in diabetic individuals. Therefore, our hypothesis is that individuals with T2DM have improved glycemic levels after periodontal treatment because one of the molecules that act in this process is IRS-2 (who acts as an important biomarker); and that SOD also contributes because it decreases the glyco-oxidative stress. The overall objective of this longitudinal non-randomized clinical study is to verify whether IRS-2 and SOD-1 act as biomarkers of the homeostasis of glycemic metabolism and glyco-oxidative stress, and whether the gene and protein expressions of these molecules are modulated by the periodontal treatment. Methodology: 30 individuals will be investigated in each group: T2DM; Periodontitis; T2DM_Compensated+P; T2DM_Decompensated+P; and Control. Each participant will have their glycemic, lipid and periodontal profile examined before and after (45, 90 and 180 days) the end of the periodontal treatment. Patients in the P and T2DM+P groups will receive non-surgical and/or surgical periodontal treatment (following criteria from the literature), and individuals in the Control and DM2 groups will receive prophylaxis and reinforcement of oral hygiene instruction (in the same periods). We will evaluate the clinical and biochemical parameters of each participant, the gene expression of IRS2 and SOD1, the quantification and activity of SOD (by spectrophotometry) in saliva before and after the periodontal treatment. Patients with indication for treatment that can obtain gingival tissue, histological and stereometric evaluations will be performed focusing on the inflammatory aspects, in addition to the immunolocalization of IRS-2 in the gingival tissue (immunohistochemistry). Linear and/or multiple logistic regressions and correlation analyses will be performed to verify the association of IRS-2 and SOD-1 with glycemic, lipid and periodontal parameters, comparing data between groups in the different periods before and after the periodontal treatment. Through this clinical study, we will verify whether these molecules can be considered useful biomarkers for clinical follow-up of patients with T2DM and P. These results will be combined with those obtained from other key molecules that are being investigated by our group in the same patients.