Toward precision acupuncture: phlegm-dampness pattern as a candidate metabolic-microbial endotype in posterior...

Posterior circulation ischemic vertigo (PCIV) denotes vertigo attributable to ischemia in the vertebrobasilar territory. It overlaps with the vascular vertigo categories of the Bárány Society diagnostic criteria and may indicate posterior circulation stroke or transient ischemic attack, so timely vascular evaluation is essential. In traditional Chinese medicine (TCM) theory, phlegm-dampness is regarded as a principal pathological product in vertigo, and pattern-based prescribing frequently targets it; whether phlegm-dampness pattern in PCIV corresponds to a biologically defined patient subgroup is unknown. This narrative review critically appraises the evidence behind that possibility. We searched PubMed, Embase, Web of Science, the Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang from inception to June 30, 2026. Direct clinical evidence in PCIV is limited to trials and meta-analyses of low certainty indicating that acupuncture, alone or as an adjunct, increases vertebrobasilar blood-flow velocity and improves symptom scores; transcranial Doppler velocity is not equivalent to tissue perfusion, and the composite "clinical effective rate" is a non-standardized outcome. Biomarker studies link phlegm-dampness constitution-assessed in non-PCIV cohorts-to dyslipidemia, low-grade inflammation, and gut microbiome alterations including depletion of Flavonifractor plautii and its product phytosphingosine. Mechanistic studies, conducted almost entirely in healthy volunteers or animal models, suggest that acupuncture can modulate cerebrovascular hemodynamics, inflammatory and oxidative-stress signaling, and gut-brain communication. Integrating these strands, we propose a candidate metabolic-microbial endotype framework as a hypothesis-generating model rather than an established entity: the proposed abnormalities have not been shown to coexist in pattern-defined PCIV patients, nor to predict differential response to acupuncture. Pattern-stratified trials with pre-specified biomarker panels are needed to test the framework.