Altered Intercellular Communication

What it is

Cells coordinate across tissues through hormones, growth factors, cytokines, neurotransmitters, and extracellular vesicles. With age these signals shift: sex hormones decline, growth hormone and IGF-1 trajectories change, the immune system skews toward inflammation, and the gut microbiome alters its metabolite output.

Why it matters in aging

Many age-related diseases — type-2 diabetes, sarcopenia, osteoporosis, neurodegeneration — are best framed as breakdowns in inter-tissue signalling rather than failures of any single cell. Chronic low-grade inflammation (“inflammaging”) is the most consistent communication-level change measured in human cohorts.

Mechanisms

• Inflammaging — rising IL-6, TNF-α, CRP independent of overt infection.
• Hormone changes — menopause, andropause, declining thymic function.
• Extracellular vesicles carry mRNA, miRNA, and protein cargo between tissues; their content shifts with age.
• Microbiome metabolites (SCFAs, bile acids, TMAO) modulate systemic signalling.

What’s being studied

Anti-inflammatory interventions (low-dose IL-2, JAK inhibitors), exercise (consistently anti-inflammatory), Mediterranean-style diet, and microbiome modulation are all explored. Direct “rejuvenation” via young plasma factors remains controversial.

Related entries

See also: Chronic inflammation, Dysbiosis, Exercise.