Oxidative stress plays a crucial role in dementia pathogenesis; however, its impact on salivary secretion and salivary qualities is still unknown. This study included 80 patients with moderate dementia and 80 healthy age- and sex-matched individuals. Salivary flow, antioxidants (salivary peroxidase, catalase, superoxide dismutase, uric acid and total antioxidant capacity), and oxidative damage products (advanced oxidation protein products, advanced glycation end products (AGE), 8-isoprostanes, 8-hydroxy-2’-deoxyguanosine and total oxidant status) were estimated in non-stimulated and stimulated saliva, as well as in plasma and erythrocytes. We show that in dementia patients the concentration/activity of major salivary antioxidants changes, and the level of oxidative damage to DNA, proteins and lipids is increased compared to healthy controls. Non-stimulated and stimulated salivary secretions were significantly reduced in dementia patients. The deterioration in mini mental state examination (MMSE) score correlated with salivary AGE levels, which when considered with receiver operating characteristic (ROC) analysis, suggests their potential role in the non-invasive diagnosis of dementia. In conclusion, dementia is associated with disturbed salivary redox homeostasis and impaired secretory function of the salivary glands. Salivary AGE may be useful in the diagnosis of dementia.

Serum carbohydrate-deficient transferrin (CDT), an 80 kDa glycoprotein, is one of the most commonly employed biomarkers to detect alcohol dependence. Some salivary glycoproteins such as α-amylase, clusterin, haptoglobin, light/heavy-chain immunoglobulin, and transferrin, which alter glycosylation in alcohol-dependent persons, have been suggested to be potential alcohol markers. However, their identification is based on indirect analysis of lectin glycosidic bonds and molecular weight. We investigated the CDT content in the saliva of alcohol- and nicotine-dependent men. The CDT concentration (ng/mL, ng/mg protein) was determined by an Enzyme-Linked Immunosorbent Assay (ELISA) commercial kit in 55 men: 20 healthy social drinkers (C), 10 chronic cigarette smokers (S), 10 alcohol-dependent non-smokers (A), and 15 alcohol-dependent smokers (AS). Surprisingly, there were no differences in the concentrations of CDT between the studied groups. Salivary pH was the lowest in the AS and the highest in the A group. Therefore, salivary CDT cannot be used as an alcohol dependence marker as measured by ELISA. We suggest that direct identification of glycoproteins is necessary to search for potential salivary alcohol biomarkers. Molecules smaller than 40 kDa, which easily translocate from blood to the saliva, might be preferred as salivary alcohol markers.