Research on the Mechanism and Application of Acupuncture Therapy for Asthma: A Review

This comprehensive review examines the mechanisms by which acupuncture treats asthma, a condition affecting approximately 300 million people worldwide. The authors analyzed clinical and experimental evidence from the past 15 years, focusing on four main categories of mechanisms: fMRI-based neuromodulation, cellular recognition/immune responses, intracellular mechanisms, and ligand-receptor signaling pathways. The research reveals that acupuncture acts through multiple pathways to treat asthma. On the neurologic side, functional magnetic resonance imaging studies have shown that stimulation of specific points such as Dazhui (GV-14), Fengmen (BL-12), and Feishu (BL-13) alters functional connectivity in brain regions such as the anterior insula and anterior cingulate cortex, areas associated with the processing of inflammation and stress.

These findings suggest that acupuncture modulates activity of the autonomic nervous system and the hypothalamic-pituitary-adrenal axis. From the immunologic standpoint, acupuncture has demonstrated the ability to regulate the balance between Th1/Th2 and Treg/Th17 cells, fundamental in the pathogenesis of asthma. The studies showed a significant reduction in pro-inflammatory cytokines such as IL-4, IL-5, IL-13, and IL-17, while increasing the production of IFN-γ and IL-10, anti-inflammatory cytokines. The therapy also reduced the activation of group 2 innate lymphoid cells (ILC2s), important in the type 2 inflammation characteristic of allergic asthma.

In intracellular mechanisms, acupuncture has been shown to regulate autophagy, endoplasmic reticulum stress, and epigenetic changes. Particularly interesting was the finding that stimulation of the Zusanli (ST-36) point can improve genetic features of offspring, suggesting lasting epigenetic effects that may influence asthma heritability. The review also identified the neurotransmitters and small molecules involved in the therapeutic effects. Acupuncture has been shown to modulate substances such as acetylcholine, substance P, and nitric oxide, which are crucial in airway smooth muscle contraction and neurogenic inflammation.

In addition, the therapy influenced hormones of the hypothalamic-pituitary-adrenal axis, including ACTH and cortisol, which control inflammatory responses. Analysis of acupuncture points revealed that Feishu (BL-13), Dazhui (GV-14), Fengmen (BL-12), and Zusanli (ST-36) are the most clinically used, with Feishu being particularly effective due to its anatomical location related to the nerve segments that innervate the lungs. Clinical studies showed significant improvements in parameters such as FEV1 (forced expiratory volume in the first second) and PEF (peak expiratory flow). The clinical implications are significant.

Acupuncture can serve as adjuvant therapy to inhaled corticosteroids, potentially reducing their side effects and offering an option for patients with glucocorticoid resistance. Acupuncture's ability to modulate multiple pathways simultaneously suggests advantages over therapies that target single targets. However, the review also identifies important limitations. Most mechanistic studies have been performed in animal models, limiting direct translatability to humans.

Clinical trials often have small samples and significant bias, making it difficult to assess research quality. In addition, the limited diversity in animal models (mainly induced by ovalbumin) may not reflect the complexity of human asthma subtypes. The authors suggest that future research should combine neuromodulation studies with molecular-based analyses, use fMRI as a non-invasive method for clinical studies, and develop more diverse models to better capture the different asthma endotypes. This integrated approach may facilitate the development of more standardized acupuncture protocols targeted to specific asthma subtypes.