Hypothesis

Microbial‑derived inflammatory signals raise the informational entropy of neuronal and glial nuclei, causing telomeres to shorten faster than predicted by mitotic count alone. This entropy‑driven telomere attrition serves as a read‑out of gut‑brain axis dysregulation and contributes to the pathophysiology of depression and anxiety.

Mechanistic Reasoning

1. The gut microbiome releases metabolites (e.g., LPS, secondary bile acids, altered SCFAs) that activate Toll‑like receptors and NF‑κB signaling in intestinal epithelial cells, propagating systemic inflammation.
2. Inflammatory cytokines increase reactive oxygen and nitrogen species in the brain, elevating thermal noise and inducing erroneous base‑excision repair. According to the Landauer principle, each erroneous repair event dissipates kT ln 2 of free energy, raising the informational entropy of chromatin.
3. Telomeric repeats are especially susceptible to entropy‑driven loss because their G‑rich sequences form G‑quadruplexes that are prone to oxidative damage; entropy increase thus translates into measurable telomere shortening independent of replication rounds.
4. Shortened telomeres trigger DNA‑damage responses that alter neuronal excitability and neurogenesis, linking microbial entropy to behavioral phenotypes.

Testable Predictions

• Prediction 1: Individuals with clinically significant depression or anxiety will show higher telomere entropy—measured as increased variance in single‑telomere length distributions and greater oxidative telomere damage (8‑OH‑dG) — than matched controls, even after adjusting for age and leukocyte turnover.
• Prediction 2: Fecal microbiome profiles enriched for LPS‑producing Proteobacteria and depleted of butyrate‑producing Faecalibacterium will correlate positively with telomere entropy scores.
• Prediction 3: Administration of a probiotic formulation known to reduce LPS translocation (e.g., L. plantarum PS128) will lower systemic inflammatory markers, decrease brain oxidative stress, and stabilize telomere entropy over a 12‑week period, whereas a placebo will not.

Experimental Design (Falsifiable)

• Recruit 120 adults meeting DSM‑5 criteria for major depressive disorder or generalized anxiety disorder and 60 healthy controls.
• Collect stool for 16S rRNA sequencing, plasma for IL‑6, TNF‑α, LPS‑binding protein, and CSF or PET‑derived markers of brain oxidative ROS (if feasible).
• Perform single‑telomere sequencing (STELA or Telomere shortest length assay) on peripheral blood mononuclear cells to compute telomere length variance and oxidative lesion frequency.
• Randomly assign the patient cohort to receive L. plantarum PS128 (1 × 10¹⁰ CFU daily) or placebo for 12 weeks; repeat all assays at baseline and endpoint.
• Statistical analysis: mixed‑effects models testing interaction between time, treatment, and telomere entropy; mediation analysis to assess whether changes in microbial LPS load mediate telomere entropy shifts.

Falsifiability

If the trial shows no significant difference in telomere entropy between probiotic and placebo groups, and telomere entropy does not correlate with microbial LPS load or psychiatric symptom severity, the hypothesis that gut‑derived inflammatory noise drives informational entropy‑mediated telomere shortening would be refuted. Conversely, confirmation of the predicted relationships would support the mechanistic link between microbiome‑induced entropy, telomere dynamics, and mental‑health outcomes.