Association Between Porphyromonas gingivalis and Alzheimer's Disease: A Comprehensive Review

Periodontitis has long been linked to various inflammatory, chronic, and immunological diseases, such as heart disease or diabetes. Recently, there has been increasing scientific interest in the bidirectional relationship that may exist between periodontitis and the presence and progression of Alzheimer's disease (AD), where it is hypothesized that the infiltration of oral microorganisms (mainly Porphyromonas gingivalis) into the bloodstream, which subsequently reaches the brain, causes inflammatory and neurodegenerative processes related to AD.

The purpose of this review is to determine the association between Porphyromonas gingivalis and Alzheimer's disease in older adults.

It was carried out using different databases such as PubMed, Web of Science, among others, of no more than 10 years old focused on older adult patients who have presented periodontitis and Alzheimer's disease. MESH-indexed terms were used, getting 307 articles. After removing 206 duplicates and applying inclusion criteria (language, relevance, and contribution to the study's objectives), 24 articles were selected for analysis.

Evidence has been found that gingipains produced by P. gingivalis may contribute to the formation of amyloid plaques in the brain and nerve cell damage characteristic of Alzheimer's disease. It has also been observed that P. gingivalis can enter the brain and stimulate a local immune response. Although the association is promising, more research is needed to confirm it and to develop effective treatments. These findings may have significant implications for clinical practice, potentially leading to preventive or therapeutic strategies targeting oral health as a modifiable risk factor for AD. Further research could focus on exploring these pathways and developing targeted interventions.