Potential application of brain-gut axis-based treatments in Long COVID and ME/CFS: a case-based systematic review

Abstract:

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID share clinical features including persistent fatigue, post-exertional malaise (PEM), and gastrointestinal (GI) dysfunction. Growing evidence implicates brain-gut axis dysregulation, characterized by dysbiosis, neuroinflammation within the central nervous system (CNS), increased intestinal permeability, and microbial translocation in their pathophysiology. However, therapeutic strategies targeting these pathways remain poorly defined.

Methods: We report a case of post-COVID ME/CFS successfully treated with electroacupuncture (EA)-based deep peroneal nerve stimulation which was employed to potentiate the vagal reflex. Fatigue trajectories were assessed using the Multidimensional Fatigue Inventory over 12 weeks. Based on the case, a systematic review of randomized controlled trials (RCTs) evaluating brain-gut axis-modulating interventions in ME/CFS or Long COVID was conducted.

Results: The patient exhibited a significant reduction in total fatigue, with early improvements in motivation and mental fatigue, and delayed improvement in physical fatigue following transient systemic symptom flares. Across included RCTs (n = 8, 790 participants), four investigated gut microbiome-modulating therapies and four employed nerve stimulation. Synbiotic and herbal interventions demonstrated benefits for fatigue or PEM, accompanied by alterations in specific bacterial populations or CNS metabolisms. Regarding nerve stimulation, transcranial direct current stimulation (tDCS) combined with exercise program improved fatigue, whereas standalone tDCS, auricular or peripheral TENS showed limited efficacy.

Conclusion: Brain-gut axis-based interventions may alleviate fatigue in ME/CFS and Long COVID by potentially modulating neuroinflammation, restoring microbiome balance, and improving epithelial barrier function. EA-based vagal stimulation represents a feasible option for patients with severe or treatment-resistant symptoms. Larger mechanistic studies and rigorously designed RCTs are needed to establish therapeutic targets and optimize intervention strategies.

Source: Kim DY, Youn J, Kang N, Cho SI, Ha IH. Potential application of brain-gut axis-based treatments in Long COVID and ME/CFS: a case-based systematic review. J Transl Med. 2026 Feb 10. doi: 10.1186/s12967-026-07807-w. Epub ahead of print. PMID: 41668172. https://link.springer.com/article/10.1186/s12967-026-07807-w (Full text available as PDF file)

From tradition to healing: the promise of acupuncture in managing chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is a global public health problem affecting more than 65 million patients worldwide. The combined prevalence rate of CFS was 45.2% after 4 weeks in patients with novel coronavirus. Women, people over 40 years of age, and low-income people are susceptible groups, which have a significant impact on immune, nervous, endocrine, and other system functions.

First, from the perspective of epidemiology, this paper reviews the global epidemic trend of CFS, the differences in incidence and prevalence in different regions and populations, and risk factors such as heredity, infection, and childhood trauma. Second, the development of diagnostic techniques for CFS, including the evolution of clinical diagnostic criteria, research progress on immune and metabolic biomarkers, and the application of MRI and other imaging techniques in the diagnosis of CFS, is described, followed by an in-depth discussion of the genetics of CFS, including genetic susceptibility, genomic association, and familial aggregation. The pathophysiological mechanism of CFS was also analyzed, revealing abnormalities in NK cell function and immune factors in the immune system, dysfunction of the hypothalamic-pituitary-adrenal axis in the neuroendocrine system, and disorders of energy and lipid metabolism in the metabolic system.

This paper focuses on the study of acupuncture and moxibustion treatment of CFS, traces back to the historical application of acupuncture and moxibustion treatment of CFS, analyzes the relationship between the pathological mechanism of CFS and acupuncture and moxibustion intervention, expounds the theoretical basis of traditional Chinese medicine and modern mechanism of action of acupuncture and moxibustion treatment, and introduces the results of clinical trials, efficacy evaluation methods, and individualized treatment strategies for acupuncture and moxibustion treatment of CFS.

The innovative application of acupuncture techniques, such as electroacupuncture and acupoint catgut embedding, as well as the synergistic effect of acupuncture combined with traditional Chinese medicine and psychotherapy, are shown. At the same time, disputes and challenges in the efficacy, safety, and ethics of acupuncture treatment for CFS were pointed out, and future research directions, potential breakthroughs, and international cooperation opportunities of acupuncture treatment for CFS are discussed. This study provides a comprehensive reference for clinical treatment and research on CFS.

Source: Wang D, Yang T, Cui Y, Qu Y, Feng C, Sun Z, Zhang M. From tradition to healing: the promise of acupuncture in managing chronic fatigue syndrome. Front Med (Lausanne). 2026 Jan 20;12:1724290. doi: 10.3389/fmed.2025.1724290. PMID: 41641244; PMCID: PMC12865710. https://pmc.ncbi.nlm.nih.gov/articles/PMC12865710/ (Full text)

Exploring the central mechanism of mind-regulation electroacupuncture in treatment of chronic fatigue syndrome with anxiety and depression comorbidity based on functional magnetic resonance imaging

Abstract:

Objectives: To observe the changes in the regional homogeneity (ReHo) and functional brain network in treatment of chronic fatigue syndrome (CFS) with anxiety and depression comorbidity with the mind-regulation electroacupuncture (EA), using resting-state functional magnetic resonance imaging (rs-fMRI).

Methods: Thirty CFS patients with anxiety and depression comorbidity were enrolled from medical staffs as the observation group. The other 30 healthy subjects were recruited from medical university students as the control group, matching gender, age and education years with the observation group. No any acupuncture intervention was delivered in the control group, and EA for regulating the mind was operated in the observation group. Main points were the emotional area of Sun‘s scalp acupuncture, the regions 1 and 8 of Sun‘s abdominal acupuncture. Supplementary acupoints included Baihui (GV 20), Guanyuan (CV 4) and bilateral.

Results: The scores of the five domains in MFI-20 (i.e. general fatigue, physical fatigue, mental fatigue, reduced motivation and reduced activity), the total score of MFI-20, and the scores of SDS, SAS and PSQI in the observation group before treatment were higher than those of the control group (P<0.05). Except the score of reduced motivation in MFI-20, the scores of the other domains and the total score of MFI-20, as well as the scores of SDS, SAS and PSQI after treatment were lower than those before treatment in the observation group (P<0.05).

Compared with the values before treatment, ReHo value was increased in the the right precuneus and decreased in the left inferior temporal gyrus and the left angular gyrus of the brain in the observation group after treatment. In the observation group, when compared with the control group, ReHo values were increased in the left inferior cerebral lobe, the interhemispheric region, the right occipital lobe and the thalamus; and it was reduced in the left middle temporal gyrus, the right posterior central gyrus, the right middle temporal gyrus, the right orbital middle frontal gyrus, the paracentral lobule and the right fusiform gyrus before treatment.

In the observation group, the functional connectivity was decreased between the right thalamus and the left posterior central gyrus, the right hippocampus and the right fusiform gyrus before treatment, respectively; it was re-constructed after treatment between the right thalamus and the left posterior central gyrus, and the right fusiform gyrus.

Compared with the control group, the functional connectivity between the right thalamus and the left posterior central gyrus, the right hippocampus, and the right fusiform gyrus was reduced before treatment; while after treatment, the functional connectivity was reduced between the right thalamus and the hippocampus in the observation group. With Spearman correlation analysis between the differential brain regions and the scores of MFI-20, SAS, SDS and PSQI, it was found that the left middle temporal gyrus, the paracentral lobule, the right precuneus, and the left inferior temporal gyrus had a partial positive correlation with the above clinical scales; and the interhemispheric region, the thalamus, the right fusiform gyrus, and the right middle temporal gyrus showed a partial negative correlation.

Conclusions: There is the decrease of ReHo in many brain regions and the numbers of the local brain functional network connectivity in CFS patients with anxiety and depression comorbidity. The mind-regulation electroacupuncture therapy may relieve the clinical symptoms of the patients through adjusting the abnormal brain regions and activating emotion-related brain regions.

Source: Zeng X, Feng C, Zhang M, Cheng W, Sun Z, Yang T. Exploring the central mechanism of mind-regulation electroacupuncture in treatment of chronic fatigue syndrome with anxiety and depression comorbidity based on functional magnetic resonance imaging. Zhongguo Zhen Jiu. 2023 Jan 12;44(1):3-11. English, Chinese. doi: 10.13703/j.0255-2930.20230603-k0003. PMID: 38191152. https://pubmed.ncbi.nlm.nih.gov/38191152/

Effect of transcutaneous electrical acupoint stimulation on learning and memory ability of chronic fatigue syndrome rats and its mechanisms

Abstract:

Objective: To observe the effect of transcutaneous electrical acupoint stimulation (TEAS) on the histomorphological manifestations of hippocampal CA1 region and the expression of extracellular regulatory protein kinase (ERK), cyclic adenosine response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in chronic fatigue syndrome (CFS) rats, so as to explore the mechanisms of TEAS in improving the learning and memory abilities of CFS rats.

Methods: Forty male Wistar rats were randomly divided into normal group (10 rats) and modeling group (30 rats); then after modeling, they were selected and randomly divided into model group (10 rats) and TEAS group (10 rats). CFS rats model was prepared by sleep deprivation combined with weight-bearing swimming. Rats in the TEAS group were stimulated with Han’s acupoint nerve stimulator at bilateral “Zusanli” (ST36) and “Shenshu” (BL23) (2 Hz/15 Hz, 1-2 mA), 20 min each time, once a day for 4 weeks with 1 d rest every 6 d. The score of general conditions of rats was evaluated. The learning and memory ability was tested with Morris water maze. The morphology and ultrastructure of hippocampal CA1 region were observed by HE staining and transmission electron microscopy. The expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were detected by real time quantitative PCR and Western blot, respectively.

Results: Compared with the normal group, the score of general condition was increased (P<0.01); the escape latency was prolonged (P<0.05, P<0.01) and the times of crossing the original platform was decreased (P<0.05); the expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were decreased (P<0.05, P<0.01) in the model group. Compared with the model group, the scores of general condition on the 42nd and 49th day were decreased (P<0.05, P<0.01); the escape latency was shortened (P<0.01, P<0.05)and the times of crossing the original platform were increased (P<0.05); the expression levels of ERK, CREB and BDNF mRNAs and proteins in hippocampus were increased (P<0.01, P<0.05) in the TEAS group. The morphology of neurons in hippocampal CA1 region was normal in the normal group. In the model group, the number of neurons in hippocampal CA1 region decreased, the arrangement of nerve cells was scattered, the number of apoptotic cells increased, some nuclear structures disappeared, nuclear heterochromatin increased, the cell membrane wrinkled, the chromatin appeared empty bright area, and the crista was incomplete. Compared with the model group, the nerve cells morphology in hippocampal CA1 region was more regular, the number of apoptotic cells decreased, the chromatin and the cytoplasm were uniformly distributed, and the crista was relatively intact in the TEAS group.

Conclusion: TEAS can improve the learning and memory ability of CFS rats, the mechanisms may be related to improving the neural structure of hippocampal CA1 region and up-regulating the expression levels of ERK/CREB/BDNF.

Source: Zhong XL, Tong BY, Yang YH, Zeng HL, Lin C, Jing Y, He LL, You SJ. [Effect of transcutaneous electrical acupoint stimulation on learning and memory ability of chronic fatigue syndrome rats and its mechanisms]. Zhen Ci Yan Jiu. 2023 Apr 25;48(4):317-24. Chinese. doi: 10.13702/j.1000-0607.20221032. PMID: 37186194. https://pubmed.ncbi.nlm.nih.gov/37186194/

Electroacupuncture at BL15 attenuates chronic fatigue syndrome by downregulating iNOS/NO signaling in C57BL/6 mice

Abstract:

Chronic fatigue syndrome (CFS) has a high incidence due to the increased pressure of daily life and work in modern society. Our previous clinical studies have found the effects of electroacupuncture (EA) on CFS patients, however, the mechanism of EA on CFS is still unknown. In this study, we investigated the effects of EA on cardiac function in a CFS mouse model to explore its underlying mechanism.

The mice were randomly divided into three groups: control, CFS, and CFS mice receiving EA (CFS + EA). After behavioral assessments and echocardiographic measurement, blood and heart tissue of the mice were collected for biochemical tests, and then we evaluated the effects of EA on the CFS mouse model when nitric oxide (NO) levels were enhanced by l-arginine.

The results showed that EA ameliorated the injured motor and cardiac function. Meanwhile, EA also inhibited increased expression of inducible nitric oxide synthase (iNOS) at heart tissue and the serum NO levels in mice subjected to sustained forced swimming stress. Furthermore, the NO level in serum increased with l-arginine administration, which blocked the effects of EA on CFS mice. This study suggested that EA could improve the motor function and cardiac function in CFS mice and its effects may be associated with the down-regulation of iNOS/NO signaling.

Source: Zhu Y, Wang J, Yao L, Huang Y, Yang H, Yu X, Chen X, Chen Y. Electroacupuncture at BL15 attenuates chronic fatigue syndrome by downregulating iNOS/NO signaling in C57BL/6 mice. Anat Rec (Hoboken). 2022 May 24. doi: 10.1002/ar.24953. Epub ahead of print. PMID: 35608198. https://pubmed.ncbi.nlm.nih.gov/35608198/

Electroacupuncture improves cognitive function by inhibiting NF-κB activity in rats with chronic fatigue syndrome

Abstract:

Objective: To observe the effect of electroacupuncture (EA) on the expression of NF-κB p65 in hippocampus and the morphology of hippocampus in rats with chronic fatigue syndrome (CFS), so as to explore its mechanism in improving cognitive dysfunction of CFS.

Methods: Forty-eight SD rats were randomly divided into control, model, EA and inhibitor groups (n=12 in each group). The CFS model was established by multi-factor compound stress stimulation method. Rats of the EA group received EA (50 Hz, 1 mA) at “Baihui” (GV20), Emotional Area I and bilateral Sensory Area for 30 min, once daily for 15 days. For rats in the inhibitor group, pyrrolidine dithiocarbamate (100 mg·kg-1·d-1) was injected intraperitoneally, once a day for 15 days. Learning and memory ability was evaluated by Morris water maze test. HE staining was used to observe the morphology of hippocampus. Western blot was used to determine the expression level of NF-κB p65 in hippocampus.

Results: After mode-ling, the general status score was increased (P<0.01), the escape latency was prolonged(P<0.01), the times of crossing the platform was decreased(P<0.01), and the expression level of NF-κB p65 in hippocampus tissue was significantly increased (P<0.05) in the model group compared with the control group. Compared with the model group, the general status score was decreased (P<0.01), the escape latency was shortened(P<0.01), the times of crossing the platform was increased(P<0.01), and the expression level of NF-κB p65 in hippocampus tissue was significantly decreased (P<0.05) in the EA and inhibitor groups. HE staining showed that in the model group, the hippocampal nerve cells were arranged disorderly, the structure was loose, and the number of apoptotic bodies and inflammatory cells was significantly increased. The degree of tissue damage of the EA and inhibitor groups was milder than that of the model group.

Conclusion: EA can improve the cognitive function in CFS rats, which may be associated with its effect in inhibiting the expression of NF-κB and reducing the inflammation response in hippocampus.

Source: Feng CW, Qu YY, Sun ZR, Wang YL, Zhang P, Wang QY, Lin WJ, Zhang L, Yang TS. [Electroacupuncture improves cognitive function by inhibiting NF-κB activity in rats with chronic fatigue syndrome]. Zhen Ci Yan Jiu. 2021 Sep 25;46(9):775-81. Chinese. doi: 10.13702/j.1000-0607.200827. PMID: 34558244. https://pubmed.ncbi.nlm.nih.gov/34558244/ [Article in Chinese]

Effect of electroacupuncture at Shenshu (BL 23) and Zusanli (ST 36) on the event-related potentials of chronic fatigue syndrome

Abstract:

OBJECTIVE: To observe the effective mechanism of electroacupuncture for chronic fatigue syndrome (CFS).

METHODS: The dynamic detection of chronobiology was used to test the event-related potentials in 20 healthy subjects and 20 CFS patients. P3a and P3b latencies at 4 equidistant time points (8:00, 14:00, 20:00, 2:00) within 24 hours were collected and analyzed.

RESULTS: (1) Latency of P3a in CFS group was obviously prolonged at 14:00 compared to health group with statistical significance (P < 0.05), latency of P3b was decreased at 14:00 after electroacupuncture treatment with statistical significance compared to that of pre-treatment (P < 0.01). (2) There were obviously circadian rhythm in latency of P3a and P3b in health group (P < 0.05), which were not seen in CFS group (P > 0.05); the circadian rhythm latency of P3b restored after treatment (P < 0.05). (3) The latency acrophase of P3a and P3b pre-treatment obviously shifted backward compared to that of healthy subjects (P < 0.05), shifted forward after electroacupuncture treatment (P < 0.05).

CONCLUSION: The event-related potential circadian rhythms are lost in CFS patients. Electroacupuncture at Shenshu (BL 23) and Zusanli (ST 36) can regulate the circadian rhythm of P3a and P3b latency and improve the cognition of the patients in daytime.

 

Source: Cheng CS, Zhu YH, Liang FR, Wu X, Jin SG, Wu FP. Effect of electroacupuncture at Shenshu (BL 23) and Zusanli (ST 36) on the event-related potentials of chronic fatigue syndrome. Zhongguo Zhen Jiu. 2010 Apr;30(4):309-12. [Article in Chinese] https://www.ncbi.nlm.nih.gov/pubmed/20568438

 

The therapeutic effects of electrical acupuncture and auricular-plaster in 32 cases of chronic fatigue syndrome

Abstract:

OBJECTIVE: To observe the therapeutic effects of electrical acupuncture and auricular-plaster therapy for chronic fatigue syndrome (CFS).

METHOD: 64 CFS patients were randomly divided into two groups. 32 cases in the treatment group were treated by the electrical acupuncture and auricular-plaster therapy, and 32 cases in the control group with oral hydrocortisone.

RESULTS: The total effective rates were respectively 93.75% in the treatment group and 75.00% in the control group, with a statistically significant difference between the two groups (P < 0.05).

CONCLUSION: Electrical acupuncture and auricular-plaster therapy may show a better anti-fatigue effect than that of routine Western drugs.

 

Source: Yuemei L, Hongping L, Shulan F, Dongfang G. The therapeutic effects of electrical acupuncture and auricular-plaster in 32 cases of chronic fatigue syndrome.  J Tradit Chin Med. 2006 Sep;26(3):163-4. https://www.ncbi.nlm.nih.gov/pubmed/17078435

 

Clinical observation on electroacupuncture for treatment of chronic fatigue syndrome

Abstract:

OBJECTIVE: To observe clinical therapeutic effect of acupuncture at Back-shu acupoints of five zang-organs on chronic fatigue syndrome (CFS).

METHODS: Forty cases of CFS were treated with electroacupuncture at main acupoints Back-shu, and Fatigue Assessment Instrument (FAI) and Mental State Self-rating Scale (SCL-90) were used for assessment of therapeutic effect.

RESULTS: After electroacupuncture treatment, clinical symptoms improved. The cumulative scores of FAI decreased from 148.36 +/- 26.53 before treatment to 98.63 +/- 28.36 after treatment (P < 0.01). And the scores of somatization, depression, anxiety and interpersonal relationship in SCL-90 reduced significantly (P < 0.01).

CONCLUSION: Electroacupuncture has a definite therapeutic effect on chronic fatigue syndrome.

 

Source: Wang Q, Xiong JX. Clinical observation on electroacupuncture for treatment of chronic fatigue syndrome. Zhongguo Zhen Jiu. 2005 Oct;25(10):691-2. [Article in Chinese] http://www.ncbi.nlm.nih.gov/pubmed/16318125