Serum and Saliva Biomolecules in Periodontitis Patients with and without Alzheimer's Disease

Alzheimer's disease (AD) and periodontitis are linked to a systemic pro-inflammatory state, potentially influencing the progression of one another.

This study aims to evaluate serum and salivary IL-10, IL-18, and resistin levels between periodontitis patients with and without AD.

Forty-three periodontitis patients with AD (mild or moderate), 40 without AD were included in the study. To determine the cognitive status Mini-Mental State-Examination (MMSE) test was used. Samples of blood and saliva were collected a day after measurement of periodontal parameters. ELISA method was used to analyze IL-10, IL-18, and resistin levels both in serum and saliva samples.

No difference was detected regarding clinical periodontal parameters across both groups (P > 0.05). The periodontitis patients with AD had elevated serum IL-18 levels compared to those without AD (P < 0.05). In the AD group, salivary resistin levels were higher in severe periodontitis patients than in moderate ones (P < 0.01). Furthermore, MMSE score was correlated negatively with serum levels of IL-18 (P < 0.05), and salivary levels of resistin positively with gingival index, bleeding on probing, and probing depth (P < 0.05).

This study confirms the possible role of serum IL-18 in the inflammatory process of AD. Additionally, the present relationship between salivary resistin levels and the severity of periodontitis in AD patients needs further investigation to fully understand the implications.