Salivary Research, Centre for Host-microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK.
J Dent Res. 2020 Jun;99(6):644-649. doi: 10.1177/0022034520915486. Epub 2020 Apr 13.
The oral microbiome is one of the most stable ecosystems in the body and yet the reasons for this are still unclear. As well as being stable, it is also highly diverse which can be ascribed to the variety of niches available in the mouth. Previous studies have focused on the microflora in disease-either caries or periodontitis-and only recently have they considered factors that maintain the normal microflora. This has led to the perception that the microflora proliferate in nutrient-rich periods during oral processing of foods and drinks and starves in between times. In this review, evidence is presented which shows that the normal flora are maintained on a diet of salivary factors including urea, lactate, and salivary protein degradation. These factors are actively secreted by salivary glands which suggests these factors are important in maintaining normal commensals in the mouth. In addition, the immobilization of SIgA in the mucosal pellicle indicates a mechanism to retain certain bacteria that does not rely on the bacterial-centric mechanisms such as adhesins. By examining the salivary metabolome, it is clear that protein degradation is a key nutrient and the availability of free amino acids increases resistance to environmental stresses.
口腔微生物群是体内最稳定的生态系统之一，但目前尚不清楚其稳定的原因。口腔微生物群不仅稳定，而且具有高度多样性，这可以归因于口腔中存在多种小生境。以前的研究主要集中在与疾病有关的微生物群上，无论是龋齿还是牙周炎，最近才开始考虑维持正常微生物群的因素。这导致人们认为微生物群在口腔处理食物和饮料的营养丰富期内增殖，而在其他时间则饥饿。在这篇综述中，有证据表明，正常菌群是通过唾液因素（包括尿素、乳酸盐和唾液蛋白降解）来维持的。这些因素是由唾液腺主动分泌的，这表明这些因素在维持口腔中正常共生菌方面很重要。此外，SIgA 在黏膜黏液层中的固定化表明了一种保留特定细菌的机制，这种机制不依赖于细菌中心的机制，如黏附素。通过检查唾液代谢组学，可以清楚地看出，蛋白质降解是一种关键的营养物质，游离氨基酸的可用性增加了对环境压力的抵抗力。
