Periodontitis and Alzheimer's Disease: A Possible Comorbidity between Oral Chronic Inflammatory Condition and Neuroinflammation

Abstract

Periodontitis is an oral chronic infection/inflammatory condition, identified as a source of mediators of inflammation into the blood circulation, which may contribute to exacerbate several diseases. There is increasing evidence that inflammation plays a key role in the pathophysiology of Alzheimer's disease (AD). Although inflammation is present in both diseases, the exact mechanisms and crosslinks between periodontitis and AD are poorly understood. Therefore, this article aims to review possible comorbidity between periodontitis and AD. Here, the authors discuss the inflammatory aspects of periodontitis, how this oral condition produces a systemic inflammation and, finally, the contribution of this systemic inflammation for worsening neuroinflammation in the progression of AD.

Keywords: Alzheimer disease; amyloid beta-peptides; dementia; inflammation; neurodegenerative diseases; neurofibrillary tangles; periodontal diseases; periodontitis.

Figure 1

Schematic illustration of factors associated to microglial activation in Alzheimer’s disease (AD).

Figure 2

(A) Teeth from a chronic periodontal patient presented dental calculus, gingival recession and attachment loss. (B) Molar tooth showed in (A) extracted due to advanced periodontal disease involvement.

Figure 3

Pathogenesis of AD and periodontal disease and their relationship. AB, antibody; Aβ, β amyloid protein; BoP, bleeding on probing; CAL, clinical attachment loss; CRP, C-reactive protein; IL, interleukin; MMP, matrix metalloproteinase; PG, prostaglandin; TNF-α, tumor necrosis factor-α.