What if gut microbiota could help us age more healthily? A group of researchers from McMaster University (Canada) has confirmed previous observations that gut microbes change with age and can cause increased inflammation and premature death in mice. They report their findings in Cell Host & Microbe along with evidence that new strategies, including probiotics and prebiotics to modify the composition and rebalance the gut microbiota could be used to improve intestinal health and thus stave off diseases linked with old age.
Levels of inflammatory mediators in circulation are known to increase with age, but the underlying cause of this age-associated inflammation is debated. We find that, when maintained under germ-free conditions, mice do not display an age-related increase in circulating pro-inflammatory cytokine levels. A higher proportion of germ-free mice live to 600 days than their conventional counterparts, and macrophages derived from aged germ-free mice maintain anti-microbial activity. Co-housing germ-free mice with old, but not young, conventionally raised mice increases pro-inflammatory cytokines in the blood. In tumor necrosis factor (TNF)-deficient mice, which are protected from age-associated inflammation, age-related microbiota changes are not observed. Furthermore, age-associated microbiota changes can be reversed by reducing TNF using anti-TNF therapy. These data suggest that aging-associated microbiota promote inflammation and that reversing these age-related microbiota changes represents a potential strategy for reducing age-associated inflammation and the accompanying morbidity.
