The neuroimmune basis of anti-inflammatory acupuncture

This review article presents the evidence that the antiinflammatory actions of acupuncture are mediated via the reflexive central inhibition of the innate immune system. Both laboratory and clinical evidence have recently shown the existence of a negative feedback loop between the autonomic nervous system and the innate immunity. There is also experimental evidence that the electrical stimulation of the vagus nerve inhibits macrophage activation and the production of TNF, IL-1beta , IL-6, IL-18, and other proinflammatory cytokines. It is therefore conceivable that along with hypnosis, meditation, prayer, guided imagery, biofeedback, and the placebo effect, the systemic anti-inflammatory actions of traditional and electro-acupuncture are directly or indirectly mediated by the efferent vagus nerve activation and inflammatory macrophage deactivation. In view of this common physiological mediation, assessing the clinical efficacy of a specific acupuncture regimen using conventional double-blind placebo-controlled trials inherently lacks objectivity due to (1) the uncertainty of ancient rules for needle placement, (2) the diffuse noxious inhibitory control triggered by control-needling at irrelevant points, (3) the possibility of a dose-response relationship between stimulation and effects, and (4) the possibility of inadequate blinding using an inert sham procedure. A more objective assessment of its efficacy could perhaps consist of measuring its effects on the surrogate markers of autonomic tone and inflammation. The use of acupuncture as an adjunct therapy to conventional medical treatment for a number of chronic inflammatory and autoimmune diseases seems plausible and should be validated by confirming its cholinergicity.