Advanced glycation end products in the dental pulp

Abstract

Hyperglycemia can increase peripheral advanced glycation end products (AGE), with associated diabetic neuropathic complications. An association between glycemia and pulpal AGE, has not been elucidated, nor has the feasibility to measure pulpal AGE. The primary aim was method development to measure pulpal AGE. Secondary aims were to determine links between glycemia and local AGEs, via comparisons between HbA1c, pulpal AGEs (in inflamed vs. non-inflamed pulps), and electronic pulp test (EPT) results. Twenty-three patients underwent venipuncture and vital pulp sampling during endodontic treatment. Local NꜪ- carboxymethyl(lysine) (CML), peripheral CML and glycosylated hemoglobin (HbA1c) were compared using enzyme-linked immunosorbent assay (ELISA). CML values were normalized to protein via bicinchoninic acid (BCA) assay. Pearson's correlation was used to evaluate relationships between HbA1c and pulpal AGE, plasma AGE, and EPT readings. One-way ANOVA was used to determine differences between pulpal AGE in inflamed and non-inflamed pulps. Results: A significant correlation was observed between pulpal and plasma AGE (r=.50, p=.025). There was a significant inverse relationship between pulpal AGE and EPT values (r=-.41, p=.036) and a non-significant inverse relationship between plasma AGE and EPT (r=-.25, p=.16). There were no significant correlations between pulpal AGE and HbA1c (r=-0.08, p=0.37), or plasma AGE and HbA1c (r=0.14, p=0.29); no differences in pulpal AGE between inflamed and non-inflamed pulps (F=1.64, p=0.22). Conclusions: A laboratory method was developed by which pulpal AGE could be measured and used for analysis of biomarkers. There was a significant correlation between pulpal and plasma AGE.