Amyloid beta (A4) precursor protein expression in human periodontitis-affected gingival tissues

Area of Science:

• Oral Health and Neuroscience
• Inflammatory Diseases
• Aging Research

Background:

• Periodontitis, a destructive inflammatory gum disease, is increasingly recognized as a potential risk factor for Alzheimer's disease (AD).
• Key molecules implicated in AD pathogenesis, such as amyloid beta (A4) precursor protein (APP), interleukin-1 beta (IL-1β), and complement component 1q (C1QA), have been observed in periodontitis tissues.

Purpose of the Study:

• To quantitatively analyze the expression levels of APP, IL-1β, and C1QA in gingival tissues affected by periodontitis.
• To determine the specific localization of APP within gingival tissues.

Main Methods:

• Gene expression analysis using quantitative reverse transcription real-time polymerase chain reaction (qRT-PCR) on gingival tissue samples from 14 periodontitis patients and 14 healthy controls.
• Microarray analysis to identify significant biological pathways in periodontitis.
• Immunohistochemistry to investigate the cellular localization of APP.

Main Results:

• Significantly elevated mRNA levels of APP, IL-1β, and C1QA were observed in periodontitis-affected gingival tissues compared to healthy controls.
• APP was primarily localized in macrophages within the gingival connective tissues, beneath the epithelial layers.

Conclusions:

• Microarray and data mining analyses revealed an association between Alzheimer's disease and periodontitis.
• Differential gene expression of APP, IL-1β, and C1QA in periodontitis-affected gingival tissues suggests a potential role in AD pathogenesis.
• The presence of elevated APP, IL-1β, and C1QA transcripts and APP-expressing macrophages indicates a link between periodontitis and the pathological mechanisms of Alzheimer's disease.