25/04/2026
The Rome V neurogastroenterology chapter is out in Gastroenterology - and it sets a new conceptual baseline for the entire field.
Greenwood-Van Meerveld et al. (2026) is not a single discovery. It is a consensus framework - the document that will define what reviewers expect, what trial designs must address, and how the gut–brain axis is framed in clinical and research contexts going forward.
The central argument: the microbiome, ENS, and CNS operate as an integrated neuroimmune network. Serotonin is now positioned as the molecular thread connecting microbial metabolic output to motility, mood, and neuroinflammation - not as a peripheral signal, but as a system-level nexus.
What the review consolidates:
→ Disrupted SCFA production and kynurenine/tryptophan metabolism as transdiagnostic signatures across psychiatric and neurological conditions
→ Neuroimmune cell units (NICUs) as a new structural concept for gut–brain crosstalk
→ FMT repositioned as a causal probe - transferring disease phenotypes between organisms and moving the field from association toward mechanism
We are finalizing a mechanistic review on psychobiotics as precision modulators of this neuroimmune interface - examining how strain-specific interventions modulate microglial activation, barrier integrity, and peripheral immune priming in neurological disease. Rome V raises the bar for what mechanistic rigour now looks like in this space. It also confirms the direction.
The gap between bench and bedside is real. Is the field finally building the right tools to close it?
📖 Greenwood-Van Meerveld et al., Gastroenterology 2026;170:1099–1113
DOI: 10.1053/j.gastro.2026.01.040
