Microbiome & Chronic Diseases

Evidence Based Medicine

Aging {50000112}

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Gut Lumen


- During life, the numbers of bifidobacteria decrease from up to 90% of the total colon microbiota in vaginally delivered breast-fed infants to <5% in the colon of adults and they decrease even more in that of elderly.

- Increase in Proteobacteria during aging, which is thought to be a common change in gut microbiome ageing, irrespective of typical elderly or long-living subjects. Furthermore, the relative abundance of Faecalibacterium in the long-living people reduced when compared to the younger group across cohorts.(2)

Shared Notes

  • [1.1
    - Aging induces significant shifts in gut microbiome composition and function associated with a decline in diversity.
    - Hallmarks of aging include the presence of dysfunctional antibody-producing B cells, antigen-presenting cells, natural killer cells, and neutrophils.
    - Commonly, in aged individuals there are consistently elevated local and systemic levels of inflammatory mediators with interleukin-6 (IL-6), tumor necrosis factor-α (TNFα), IL-1β, and C-reactive protein (CRP).
    - In humans, age-related dysbiosis is characterized by a loss in Clostridiales and Bifidobacterium, with an enrichment in Proteobacteria and an overrepresentation of pathobionts such as Enterobacteriaceae.
  • [1.2
    - The abundance of seven Bifidobacterium species decreased substantially over time, whereas the levels of most Alistipes species increased.
  • [1.3
    - Urolithin A (UA) is a gut microbiome-derived natural compound that only 40% of people can naturally convert from dietary precursors at meaningful levels.
    - UA increases mitophagy and mitochondrial function and blunts excessive inflammatory responses.
    - UA increased biomarkers of mitochondrial function in preclinical models of aging and in healthy elderly people.
    - UA is a promising strategy to target health and disease conditions of aging, especially those linked to mitochondrial and muscle dysfunction.
  • [1.4
    - Adipokines, leptin and adiponectin, produced and secreted by adipocytes, are involved in regulating systemic inflammation and may be important targets for interventions to reduce the chronic systemic inflammation linked to some conditions common in aging (e.g., atherosclerosis).
    - Lower leptin levels and higher adiponectin levels in peripheral circulation have been associated with less systemic inflammation.

Common References