Oral Microbiota and Immune System Crosstalk: A Translational Research

Background: Oral pathogens may exert the ability to trigger differently the activation of local macrophage immune responses, for instance Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans induce M1-type responses, while oral commensal microbiota primarily elicit macrophage functions consistent with the M2 phenotype. Methods: In healthy individuals vs periodontal patients blood samples, the differentiation process from monocyte to M1 and M2 was conducted using two typical growth factors, the granulocyte/macrophage colony stimulating factor (GM-CSF) and the macrophage colony stimulating factor (M-CSF). Results: In contrast with the current literature our outcomes showed a noticeable increase of macrophage polarization from healthy individuals vs periodontal patients. The biological and clinical significance of these data was discussed. Conclusions: Our findings suggested that macrophages entering the central nervous system (CNS), may perform as “Troy horse” effect carrying pathogens from oral affected areas that eventually led to acute and long-term microglia-mediated inflammation able to end up into a variety of CNS diseases like Alzheimer’s, Parkinnson’s or dementia.