Asthma is one of the most widespread chronic air-way inflammatory disease characterised by bronchial hyper-responsiveness, increased mucus production, narrowing of the airways and airway remodelling. Symptoms include coughing, wheezing, shortness of breath and chest tightness. It is affecting approximately 300 million people worldwide estimated by WHO. The incidence and severity have been continually increasing, every ten seconds someone in the UK has a potentially life-threatening asthma attack and three people die every day (www.asthma.org.uk).

Asthma can be caused by extrinsic factors (e.g. allergens, aspirin) and internal factors (e.g. viral infections, stress). Although most asthmatic symptoms can be prevented by avoiding triggers and well controlled if asthmatic patients take regular inhaled corticosteroids (ICSs) with or without long-acting b2-agonists (LABAs) in combination inhalers, approximately 5% to 10% of all asthmatic patients are severe asthma which is difficult to treat (Barnes, 2012).  Furthermore systemic side effects from chronic use of ICSs and LABAs, cost of the most recent anti-IgE antibody treatment also raise issues. It has become more and more important to develop novel therapeutic approaches for the treatment of asthma.

Traditional Chinese Medicine (TCM) has a long-lasting history of effective treatment of various respiratory diseases including asthma. The efficacy and mechanisms of TCM  methods include Chinese herbal medicine, acupoint herb patching on asthma treatment will be updated in this mini review.

 

The cut-edge of Chinese Herb Medicine on asthmatic treatment

Chinese herbal medicine has been used for asthma treatment for over thousand years. Zhang Zhongjing, formal name Zhang Ji was one of the most famous Chinese physicians in history. He established special medication theory and summed up the medical experience including asthma which is still effective and widely used by Chinese physicians. In general, Chinese herb medicine needs to be organised well in a complex formula to treat disease based on unique theory and diagnosis.

Shergis et al (2016) recently conducted a systematic review of 29 studies involving 3,001 participants and concluded that herbal medicines combined with routine pharmacotherapy improved asthma outcomes greater than pharmacotherapy alone. Herbal interventions used multi-ingredients such as licorice root, crow-dipper, astragali, and angelica. Compared with routine pharmacotherapy alone, herbal medicines as add-on therapy improved lung function (FEV1: MD 7.81%, 95% CI 5.79, 9.83, I(2) = 63%; PEFR: MD 65.14 L/min, 95% CI 58.87, 71.41, I(2) = 21%); asthma control ; reduced salbutamol usage; and reduced acute asthma exacerbations over one year. Compared with placebo plus pharmacotherapy, herbal medicines as add-on therapy improved lung function (FEV1: MD 15.83%, 95% CI 13.54, 18.12 and PEFR: MD 55.20 L/min, 95% CI 33.41, 76.99). Adverse events were rare. However the included studies did not blind participants.

Evidence-based research into the efficacy and mechanisms of asthma treatment is rare. Wen (2005) reported the first double-blind, randomized, placebo-controlled trial investigating the efficacy and tolerability of an anti-asthma herbal medicine intervention (ASHMI, which contains Ling-Zhi (Ganoderma Lucidum, G lucidum), Ku-Shen (Sophora Flavescentis, S flavescentis ), and Gan-Cao (Glycyrrhiza uralensis, G urilensis)), compared to oral prednisone therapy on 91 patients with moderate- to-severe asthma. This study found that following treatment, lung function (FEV1 and peak expiratory flow values) was significantly improved in both ASHMI (64.9± 6 3.6 to 84.2± 6 5.0; P < 0.001) and prednisone (65.2± 6 3.7 to 88.4 ± 6 8.0; P < 0.001) groups. The improvement was slightly but significantly greater in the prednisone group (P < 0.05). There was a significant and similar degree of reduction in clinical symptom scores in both treated groups. No significant side effects were observed in either group. The conclusion was that ASHMI appeared to be effective and well tolerated, and may offer benefits comparable to standard prednisone therapy for some patients without side-effects associated with steroid use. ASHMI is the only anti-asthma TCM product that is a US FDA investigational new drug (IND) that has entered clinical trials.

The mechanisms  from clinical trial and asthmatic animal model research suggested that Chinese herbal medicines exhibit a broad spectrum of therapeutic effects on the major pathogenic process of asthma which  may involve anti-inflammatory and immunomodulatory effects, inhibiting airway remodelling and normalization of hypothalamus, pituitary and adrenal (HPA)-axis disturbances (Li et al., 2011).

 

Efficacy and safety of acupoint herbal patching for asthma treatment

 

In China, the use of acupoint herbal patching (AHP) in asthma management was first recorded in Zhang Shi Yi Tong in Qing Dynasty (1644–1912), and is still in popular use nowadays. As a traditional Chinese medicine technique, AHP involves externally applying a carefully selected stimulating Chinese herbs that are in hot in nature are ground into powder and mixed with ginger extract to form pellets, which are then pasted onto specific acupoints.

SAHP (SAHP) is an AHP that is applied on specific acupoints only during the San Fu period to produce preventive and/or therapeutic effects for asthma. According to the lunar calendar, Fu refers to the hottest period of the year between mid-July to mid-August, lasting 30 to 40 days. Each ten days is called one Fu, and three Fus are called as San Fu. SAHP is a comprehensive intervention that comprises percutaneous absorption of applied herbal extracts, leading to stimulation and regulation of meridians and acupoints.

Lee et (2016) conducted a system review to summarise and critically evaluate the efficacy and safety of AHP for asthma. 16 RCTs with 1287 asthmatic patients were in analyses. Treatment with AHP improved FEV1 by 13% and asthmatic symptoms by 60% over that observed with placebo. When added to conventional therapies, AHP significantly improved the FEV1/forced vital capacity ratio by 11.6% and reduced the risk of asthmatic symptoms by 69%. Compared with conventional medication, AHP significantly improved FEV1, but a substantial heterogeneity was detected. When added to Chinese herbal medicine, there were no additional benefits of AHP on pulmonary function or global symptom improvement. No serious adverse events were associated with AHP. Evidence for AHP efficacy is encouraging, but not conclusive, because of clinical diversity and the high risk of bias in the examined studies.

Zhou et al (2017) et al summarised the efficacy and safety of SAHP from 34 RCTs involving 3313 participants. SAHP plus conventional therapy (CT) decreased the mean frequency (times per year) of asthma exacerbations compared with CT alone, and similar effect was found for SAHP versus sham SAHP (MD: 0.42; 95%CI: 0.26–0.69; 1 RCT). For lung function (including PEF%, FEV1% and FEV1/FVC), SAHP plus CT showed better effect than CT alone, and so did SAHP versus sham SAHP on PEF and PEF%. Adverse effects in the SAHP groups were reported to be mild and well tolerated. It was concluded that SAHP alone or combined with CT appeared to be more effective than sham SAHP or CT on reduction of asthma exacerbations, improving lung function, and SAHP seems to be safe.

The AHP and SAHP can reduce airway inflammation and effectively prevents and treats asthma symptoms, possibly by regulation of serum immunoglobulin E (IgE), eosinophils, nitric oxide, T-lymphocyte subsets, and acetylcholine.

Although review papers mentioned above showed the effectiveness of TCM when used alone or in combination with conventional medicine they suggested that the findings should be interpreted with caution due to risk of bias. Further rigorously designed, large-scale trials are warranted for robust evidence.

Conclusion

The Chinese herb medicine and Acupoint Herbal Patching have some effectiveness on asthmatic treatment by reducing asthmatic symptoms and improving lung function.

However, daily clinical practice requires a complex interplay between experience and training, research and judgement. Therefore, evidence from RCTs combined with real-life studies (e.g pragmatically designed clinical trials, cohort study) evidence will possibly provide a fuller picture of intervention effectiveness of TCM on asthmatic treatment.

Reference:

Grateful acknowledgements are due to Drs Barnes PJ, Wen MC, Li XM, Shergis JL, Lee SH, Zhou F and colleagues (This paper was based on their articles cited in above Reference section), as well as to Drs. Cai-Long Fang and Bai-Yun Zeng for their work in preparing this briefing paper.