Effects of glycation end-products on the dental pulp in patients with type 2 diabetes

This ex vivo study aimed to compare protein expression of advanced glycation end-products (AGE) and receptor (RAGE), and the levels of selected genes associated with inflammation and collagen within dental pulp tissue from patients with type 2 (T2D) diabetes and non-T2D.

Noncarious extracted permanent molar teeth from patients with well-controlled T2D (n = 19) and non-T2D (controls) (n = 19) were collected and compared. The coronal pulp was examined using immunohistochemistry (IHC) (n = 10 per group) for anti-AGE and anti-RAGE. Quantitative PCR (n = 9 per group) was used to analyse the gene expression levels of NFKB, S100A12 and COLIA1. Data analyses were performed between the groups using GraphPad Prism using Pearson correlation, Shapiro-Wilk and Mann-Whitney U-tests, and multiple regression using SPSS.

AGEs were distributed diffusely throughout the pulp extracellular matrix associated with collagen fibres and were present on several cell types. RAGE was expressed at the pulp-dentine interface and was observed on odontoblasts, immune cells, endothelial cells and fibroblasts. Semi-quantitative analysis of IHC samples showed significantly increased expression of AGE (p < .0001) and RAGE (p = .02) in T2D samples compared with controls. The expression of NFKB (p < .0001), S100A12 (p < .0001) and COLIA1 (p = .01) genes were significantly higher in the T2D pulp, and multivariate logistic regression analysis showed that these findings were not affected by age.

T2D may exert a similar glycation response in the dental pulp to other body sites. This could occur through activation of NF-κB pathways with a concomitant increase in genes associated with inflammation and collagen.