Table_1_Dynamics of the Salivary Microbiome During Different Phases of Crohn's Disease.DOCX

Crohn's disease is a chronic disorder that typically affects the gastrointestinal tract. The increased incidence in the recent years, especially in Asian countries, prompts for performing studies and gain newer insights into the etiology and pathogenesis of the disease. Among other causative factors, gut microbiome and its cross-talk with the salivary microbiome is a known factor that has a plausible role in the pathogenesis of Crohn's disease. The gut microbiome has been extensively studied, however, the salivary microbiome and its dynamics during different phases of this disease remain understudied. In this study, we obtained saliva samples from the patients during active and remission phases of the disease and compared them with control samples and highlighted the differences in taxonomic as well as predicted functional pathways among them. Our results indicated that the α and β diversities were significantly lower during the active phase in contrast with remission phase and healthy samples. In general, Firmicutes were most abundant among the three sample groups, followed by Bacteroidetes and Proteobacteria. Genus level distribution highlighted Streptococcus, Neisseria, Prevotella, Haemophilus, and Veillonella as the five most abundant taxa. Differential abundance analysis of the three sample groups identified significant enrichment of 30 bacterial taxa in the active phase that included g_Prevotella, f_Prevotellaceae, and p_Bacteroidetes. Furthermore, remission phase and control also exhibited significant enrichment of 24 and 22 bacterial taxa, respectively. Eleven differentially abundant pathways were also identified, four were significantly enriched in healthy controls whereas other seven were significantly enriched in active phase of the disease. Several important pathways, such as ribosome biogenesis and Energy metabolism were depleted in the active phase. Our study has highlighted several taxa and functional categories that could be implicated with the onset of Crohn's disease and thus have the potential to serve as biomarkers of the active disease. However, these findings require further validation through functional studies in the future.

克罗恩病是一种慢性疾病，通常影响胃肠道。近年来，特别是在亚洲国家，其发病率的上升促使研究人员进行深入研究，以获得关于疾病病因学和发病机制的新的见解。在众多致病因素中，肠道菌群及其与唾液菌群的相互作用是一个已知因素，它在克罗恩病的发病机制中可能扮演着合理的作用。尽管肠道菌群已被广泛研究，但唾液菌群及其在不同疾病阶段的动态变化仍鲜有研究。在本研究中，我们从疾病活动期和缓解期患者处采集唾液样本，并与对照组样本进行比较，突出了它们在分类学以及预测功能通路方面的差异。我们的结果显示，与缓解期和健康样本相比，活动期的α和β多样性显著降低。总体而言，在三个样本组中，厚壁菌门是最丰富的，其次是拟杆菌门和变形菌门。在属水平上，链球菌属、奈瑟菌属、普雷沃菌属、嗜血杆菌属和韦荣球菌属被认为是五种最丰富的菌类。对三个样本组进行差异丰度分析，发现活动期中30种细菌类群显著富集，包括g_Prevotella、f_Prevotellaceae和p_Bacteroidetes。此外，缓解期和对照组也分别表现出24和22种细菌类群的显著富集。还确定了11种差异丰度通路，其中四种在健康对照组中显著富集，而其他七种在疾病活动期显著富集。一些重要的通路，如核糖体生物合成和能量代谢，在活动期中减少。本研究突出了几个可能与克罗恩病发病相关的菌类和功能类别，因此有潜力作为活动性疾病的生物标志物。然而，这些发现需要通过未来的功能研究进行进一步验证。