College of Life and Environmental Sciences, University of Exeter, UK.
College of Life and Environmental Sciences, University of Exeter, UK.
Redox Biol. 2021 May;41:101933. doi: 10.1016/j.redox.2021.101933. Epub 2021 Mar 5.
Many oral bacteria reduce inorganic nitrate, a natural part of a vegetable-rich diet, into nitrite that acts as a precursor to nitric oxide, a regulator of vascular tone and neurotransmission. Aging is hallmarked by reduced nitric oxide production with associated detriments to cardiovascular and cognitive function. This study applied a systems-level bacterial co-occurrence network analysis across 10-day dietary nitrate and placebo interventions to test the stability of relationships between physiological and cognitive traits and clusters of co-occurring oral bacteria in older people. Relative abundances of Proteobacteria increased, while Bacteroidetes, Firmicutes and Fusobacteria decreased after nitrate supplementation. Two distinct microbiome modules of co-occurring bacteria, that were sensitive to nitrate supplementation, showed stable relationships with cardiovascular (Rothia-Streptococcus) and cognitive (Neisseria-Haemophilus) indices of health across both dietary conditions. A microbiome module (Prevotella-Veillonella) that has been associated with pro-inflammatory metabolism was diminished after nitrate supplementation, including a decrease in relative abundance of pathogenic Clostridium difficile. These nitrate-sensitive oral microbiome modules are proposed as potential pre- and probiotic targets to ameliorate age-induced impairments in cardiovascular and cognitive health.
许多口腔细菌将富含蔬菜饮食中的天然成分无机硝酸盐还原为亚硝酸盐，亚硝酸盐作为一氧化氮的前体，一氧化氮是血管张力和神经递质的调节剂。随着年龄的增长，一氧化氮的产生减少，随之而来的是心血管和认知功能的损害。本研究应用系统水平的细菌共现网络分析，对 10 天的硝酸盐饮食和安慰剂干预进行了分析，以测试生理和认知特征与老年人口腔共现细菌群之间关系的稳定性。硝酸盐补充后，变形菌门的相对丰度增加，而拟杆菌门、厚壁菌门和梭杆菌门的相对丰度减少。两个对硝酸盐补充敏感的独特共生细菌微生物群模块与心血管（罗氏链球菌）和认知（奈瑟菌-嗜血杆菌）健康指数之间存在稳定的关系，这两个模块在两种饮食条件下都很敏感。与促炎代谢相关的微生物群模块（普雷沃氏菌-韦荣球菌）在硝酸盐补充后减少，包括致病性艰难梭菌的相对丰度降低。这些对硝酸盐敏感的口腔微生物群模块被提议作为潜在的预防和益生菌靶点，以改善与年龄相关的心血管和认知健康损害。
