Periodontal Biology Laboratory, Faculty of Dentistry, Universidad de Chile, Santiago, Chile.
Department of Periodontology, School of Dentistry, Universidad Científica del Sur, Lima, Perú.
Oral Dis. 2023 Jan;29(1):21-28. doi: 10.1111/odi.14054. Epub 2021 Nov 10.
Periodontitis is a chronic non-communicable disease caused by a dysbiotic microbiota. Pathogens can spread to the bloodstream, colonize other tissues or organs, and favor the onset of other pathologies, such as Alzheimer's disease (AD). Pathogens could permanently or transiently colonize the brain and induce an immune response. Thus, we analyzed the evidence combining oral bacteria's detection in the brain, both in animals and humans affected with AD. This systematic review was carried out following the PRISMA guideline. Studies that detected oral bacteria at the brain level were selected. The search was carried out in the Medline, Latindex, SciELO, and Cochrane Library databases. SYRCLE tool and Newcastle-Ottawa Scale were used for the risk of bias assessment. 23 studies were selected according to the eligibility criteria. Infection with oral pathogens in animals was related to developing neuropathological characteristics of AD and bacteria detection in the brain. In patients with AD, oral bacteria were detected in brain tissues, and increased levels of pro-inflammatory cytokines were also detected. There is evidence of a microbiological susceptibility to develop AD when the most dysbiosis-associated oral bacteria are present. The presence of bacteria in the brain is related to AD's pathological characteristics, suggesting an etiological oral-brain axis.
牙周炎是一种由微生物失调引起的慢性非传染性疾病。病原体可以传播到血液中，定植在其他组织或器官中，并有利于其他疾病的发生，如阿尔茨海默病（AD）。病原体可以永久性或暂时性地定植在大脑中，并引发免疫反应。因此，我们分析了结合口腔细菌在动物和 AD 患者大脑中检测的证据。这项系统评价是按照 PRISMA 指南进行的。选择了在大脑水平检测口腔细菌的研究。在 Medline、Latindex、SciELO 和 Cochrane Library 数据库中进行了检索。使用 SYRCLE 工具和 Newcastle-Ottawa 量表评估了偏倚风险。根据入选标准，共选择了 23 项研究。动物的口腔病原体感染与 AD 的神经病理学特征的发展有关，并且可以在大脑中检测到细菌。在 AD 患者中，在脑组织中检测到了口腔细菌，并且还检测到了促炎细胞因子水平的升高。当存在与失调最相关的口腔细菌时，存在微生物易感性以发展 AD。细菌在大脑中的存在与 AD 的病理特征有关，提示存在病因学的口腔-大脑轴。
