The microbiome influences ageing

^{© fotogurmespb – stock.adobe.com / Visualization of bacteria of the microbiome}

With increasing age, the metabolic activity of intestinal bacteria changes – to the detriment of the host, as a research team from Kiel and Jena discovered.

• Metabolic activity of the microbiome is significantly reduced in old age, as the analysis of animal data and computer models shows
• Bacteria produce fewer vital substances that the body needs. This can contribute to ageing
• The repeated and lifelong transfer of a “young” microbiome halts ageing processes in mice, according to another study from Kiel
   

The intestine is home to a complex ecosystem of microorganisms. This so-called gut microbiome plays an important role in health, disease and ageing. Various studies suggest that the microbiome “ages” and drives the host’s ageing processes. It was previously unclear which mechanisms the microbiome uses to control ageing in the host. This question was investigated by a research team led by Professor Christoph Kaleta, Faculty of Medicine at Kiel University (CAU) and Cluster of Excellence “Precision Medicine in Chronic Inflammation” (PMI), and Dr. Christiane Frahm from Jena University Hospital (UKJ). While Kiel contributed its expertise in metabolic modeling, Jena provided central experimental data for the analyses. This work was carried out as part of the Marie Sklodowska-Curie Innovative Training Network SmartAge (ITN) coordinated by Jena under Horizon 2020. 

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Stool transfer: microbiome of young mice slows down ageing

Another study by the Cluster of Excellence led by Professor Philip Rosenstiel on mice has shown that it is indeed possible to reduce ageing processes in the host and also in the microbiome. “There are already isolated indications of this from earlier studies, but for the first time we have attempted to rejuvenate the microbiome over the entire lifespan of a mouse,” explained Rosenstiel, member of the board of the Cluster of Excellence PMI and Director of the Institute of Clinical Molecular Biology (IKMB) at the Faculty of Medicine of Kiel University and the University Medical Center Schleswig-Holstein (UKSH), Kiel Campus. For this purpose, the animals were transferred stool from young mice every eight weeks for two years, while the animals in the control group received the microbiome from mice of the same age via stool transfer. “We were actually able to reduce some signs of aging,” emphasizes first author PD Dr. Felix Sommer, head of the Functional Host Microbiome Research group at the IKMB. “Movement coordination improved and the intestinal barrier was preserved.” Further analyses also revealed that fewer pro-inflammatory factors were found in the young microbiome. In the host, i.e. the mouse, typical signs of inflamm-aging decreased. Inflamm-aging, a mild, persistent inflammation in the tissue, is considered a biological feature of the ageing process and plays a role in various diseases.

Original publications:

Lena Best et al.: Metabolic modeling reveals the aging-associated decline of host-microbiome metabolic interactions in mice. Nat Microbiol. 10, 973–991 (2025). https://doi.org/10.1038/s41564-025-01959-z

Felix Sommer, Joana P. Bernardes et al.: Life-long microbiome rejuvenation improves intestinal 1 barrier function and inflammaging in mice. Microbiome 13, 91 (2025). https://doi.org/10.1186/s40168-025-02089-8

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