Altered redox homeostasis in human diabetes saliva

J Oral Pathol Med (2012) 41 : 235–241 Background: Oxidative stress has been implicated in the pathogenesis of diabetes mellitus (DM). Levels of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG), 8‐epi‐prostaglandin‐F_2α (8‐epi‐PGF2α), and total protein carbonyls were measured to assess whether DM is associated with altered salivary redox homeostasis. Methods: A total of 215 patients with diabetes and 481 healthy controls were recruited from the Department of Endocrinology at the Jewish General Hospital in Montreal. Levels of oxidative biomarkers were assayed using enzyme‐linked immunosorbent assay (ELISA) in whole unstimulated saliva. Associations of the redox data with exposure to insulin, metformin and dietary control were assessed by logistic regression analyses. Results: We observed (i) significantly higher mean levels of 8‐OHdG and protein carbonyls in whole unstimulated saliva of patients with diabetes compared to controls, (ii) higher mean levels of protein carbonyls in type 1 diabetes as well as higher mean levels of 8‐OHdG and protein carbonyls in type 2 diabetes compared to controls, (iii) elevated levels of protein carbonyls in diet‐controlled patients and in patients with diabetes on insulin and metformin, (iv) elevated levels of 8‐OHdG in patients on metformin, and (v) significant associations between subjects with DM and salivary 8‐OHdG and protein carbonyls. Conclusion: DM is associated with increased oxidative modification of salivary DNA and proteins. Salivary redox homeostasis is perturbed in DM and may inform on the presence of the disease and efficacy of therapeutic interventions.