What intrinsic factors influence responsiveness to acupuncture in pain?: a review of pre-clinical studies that used responder analysis

Neurogenic Hypotension and Bradycardia Modulated by Electroacupuncture in Hypothalamic Paraventricular Nucleus

Electroacupuncture (EA) stimulates somatic median afferents underlying P5-6 acupoints and modulates parasympathoexcitatory reflex responses through central processing in the brainstem. Although decreases in blood pressure and heart rate by the neural-mediated Bezold-Jarisch reflex responses are modulated by EA through opioid actions in the nucleus tractus solitarius and nucleus ambiguus, the role of the hypothalamus is unclear. The hypothalamic paraventricular nucleus (PVN) is activated by sympathetic afferents and regulates sympathetic outflow and sympathoexcitatory cardiovascular responses. In addition, the PVN is activated by vagal afferents, but little is known about its regulation of cardiopulmonary inhibitory hemodynamic responses. We hypothesized that the PVN participates in the Bezold-Jarisch reflex responses and EA inhibits these cardiopulmonary responses through the PVN opioid system. Rats were anesthetized and ventilated, and their heart rate and blood pressures were monitored. Application of phenylbiguanide every 10 min close to the right atrium induced consistent depressor and bradycardia reflex responses. Unilateral microinjection of the depolarization blockade agent kainic acid or glutamate receptor antagonist kynurenic acid in the PVN reduced these reflex responses. In at least 70% of the rats, 30 min of bilateral EA at P5-6 acupoints reduced the depressor and bradycardia responses for at least 60 min. Blockade of the CCK-1 receptors converted the non-responders into EA-responders. Unilateral PVN-microinjection with naloxone reversed the EA inhibition. Vagal-evoked activity of the PVN cardiovascular neurons was reduced by 30 min EA (P5-6) through opioid receptor activation. These data indicate that PVN processes inhibitory cardiopulmonary reflexes and participates in EA-modulation of the neural-mediated vasodepression and bradycardia.

Transcutaneous Electrical Acupoint Stimulation Combined With Auricular Acupressure Reduces Postoperative Delirium Among Elderly Patients Following Major Abdominal Surgery: A Randomized Clinical Trial

Background

Postoperative delirium is common in elderly patients following major surgery. This study aimed to assess the effect of transcutaneous electrical acupoint stimulation combined with auricular acupressure on the incidence of postoperative delirium among older patients undergoing major abdominal surgery.

Methods

In this single-center, randomized controlled clinical trial, 210 patients aged 65 years or older undergoing major abdominal surgery were randomized to receive either intervention treatment (transcutaneous electrical acupoint stimulation started at 30 min before anesthesia until the end of the surgery, followed by intermittent auricular acupressure in the first three postoperative days; n = 105) or standard care (n = 105). The primary outcome was the incidence of delirium at the first seven postoperative days or until hospitalization depended on which came first. Secondary outcomes included delirium severity, opioid consumption, postoperative pain score, sleep quality, length of postoperative hospital stay, and postoperative 30-day complications. Enrollment was from April 2019 to March 2020, with follow-up ending in April 2020.

Results

All of the 210 randomized patients [median age, 69.5 years, 142 (67.6%) male] completed the trial. The incidence of postoperative delirium was significantly reduced in patients received intervention treatment (19/105 (18.1%) vs. 8/105 (7.6%), difference, –10.5% [95% CI, –1.5% to –19.4%]; hazard ratio, 0.41 [95% CI, 0.18 to 0.95]; P= 0.023). Patients in the control group had a higher postoperative Memorial Delirium Assessment Scale (4 vs. 3; difference, –1; 95% CI, –1 to 0; P = 0.014) and a greater increase in Pittsburgh Sleep Quality Index score from baseline to postoperative day three (2.5 vs. 2.0; difference, –1; 95% CI, –2 to –1; P < 0.001) than patients in the intervention group. No significant difference was observed as of other secondary outcomes.

Conclusion

In elderly patients undergoing major abdominal surgery, transcutaneous electrical acupoint stimulation combined with auricular acupressure reduced the incidence of postoperative in-hospital delirium compared with standard care. A multicenter, randomized clinical trial with a larger sample size is necessary to verify these findings.

Clinical Trial Registration

[https://clinicaltrials.gov], identifier [NCT03726073].

Identifying Dose Components of Manual Acupuncture to Determine the Dose-Response Relationship of Acupuncture Treatment: A Systematic Review

The dose-response relationship is a hallmark of pharmacological studies. However, this relationship has not been fully established in acupuncture research. This systematic review aims to provide the characteristics of the dose-response relationship in acupuncture research. We further summarized the differences in acupuncture effects according to dose components. Dose components of acupuncture were categorized into three groups: number of needles, stimulation intensity, and total number/frequency of treatments. The PubMed database was used to identify studies examining the effects of different doses of acupuncture from the establishment of the database to August 13, 2020. Dose components and responses were extracted from each study, and the results of low- and high-dose conditions were compared. Fourteen studies were included in this study. Of the included studies, 37.5% showed statistically significant enhanced responses to acupuncture treatment under high-dose conditions compared to low-dose conditions. Significant differences between high- and low-dose conditions were observed most frequently in studies that used various stimulation intensities (four out of six studies), followed in order by studies that used various numbers of needles (two out of seven studies), and those that used various numbers or frequencies of treatment (none of the three studies). Responses were categorized into symptom changes, physiological changes, experimentally induced pain/stimuli perception, and needling sensation. Stimulation intensity, which is considered one of the most important needling components, might indeed have a great impact on clinical responses to acupuncture.

Effectiveness of electroacupuncture as a treatment for osteoporosis: A systematic review and meta-analysis

BACKGROUND

Osteoporosis (OP) results in an increased risk of fragility fractures, representing a major public health problem. In preventing OP, complementary and alternative medicine, such as acupuncture, was recommended because of the low efficiency and side effects of medications. Recently, there is insufficient evidence on electroacupuncture as an effective therapy for OP management. Hence, we evaluated the effectiveness of electroacupuncture for OP treatment.

METHODS

We conducted a systematic review and meta-analysis of clinical studies on patients with OP. Five databases (PubMed, Embase, Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, and Wanfang) were searched from the earliest publication date to March 12, 2020. Randomized controlled trials (RCTs) were included if electroacupuncture was applied as the sole treatment or as an adjunct to other treatments compared with medications in patients with OP. The measurement outcomes included serum aminoterminal propeptide of type I procollagen (PINP) and C-telopeptide of type I collagen (CTX) levels, bone mineral density (BMD) of lumbar, and visual analog scale scores for OP-related pain. Acupoints were extracted when available.

RESULTS

In total, 11 RCTs involving 731 participants were included for further meta-analysis. The meta-analysis showed that the use of electroacupuncture as a sole treatment or as an adjunct to other treatments could relieve OP-related pain compared with medications [mean difference (MD) =  -0.58, 95% confidence interval (CI); MD =  -0.97 to -0.19, P = .003, I2 = 88%; MD =  -1.47, 95% CI = -2.14 to -0.79, P < .001, I2 = 96%). Meanwhile, the results showed a favorable effect of electroacupuncture on decreasing serum beta-CTX levels. However, there were no significant differences in serum PINP levels and BMD of lumbar. Shenshu (BL23) was the most frequent acupoint stimulation among these studies.

CONCLUSIONS

The application of electroacupuncture as an independent therapy or as an adjunct to other treatments might attenuate OP-related pain and serum beta-CTX levels. However, to overcome the methodological shortcomings of the existing evidence, due to a small size of samples and high risk of bias in these included RCTs, further rigorous studies are required.

Identifying patients with chronic pain who respond to acupuncture: results from an individual patient data meta-analysis

BACKGROUND

In a recent individual patient data meta-analysis, acupuncture was found to be superior to sham and non-sham controls in patients with chronic pain. It has been suggested that a subgroup of patients has an exceptional response to acupuncture. We hypothesized the presence of exceptional acupuncture responders would lead to a different distribution of pain scores in acupuncture versus control groups, with the former being skewed to the right.

METHODS

This individual patient data meta-analysis included 39 high-quality randomized trials of acupuncture for chronic headache, migraine, osteoarthritis, low back pain, neck pain and shoulder pain published before December 2015 (n = 20,827). In all, 25 involved sham acupuncture controls (n = 7097) and 25 non-acupuncture controls (n = 16,041). We analyzed the distribution of change scores and calculated the difference in the skewness statistic-which assesses asymmetry in the data distribution-between acupuncture and either sham or non-acupuncture control groups. We then entered the difference in skewness along with standard error into a meta-analysis.

FINDINGS

Control groups were more right-skewed than acupuncture groups, although this difference was very small. The difference in skew was 0.124 for non-acupuncture-controlled trials (p = 0.047) and 0.141 for sham-controlled trials (p = 0.029). In a pre-specified sensitivity analysis excluding three trials with outlying results known a priori, the difference in skew between acupuncture and sham was no longer statistically significant (p = 0.2).

CONCLUSION

We did not find evidence to support the notion that there are exceptional acupuncture responders. The challenge remains to identify features of chronic pain patients that can be used to distinguish those that have a good response to acupuncture treatment.

Perioperative acupuncture medicine: a novel concept instead of acupuncture anesthesia

Objective:

To confirm that acupuncture applied to patients would improve the clinical curative effect and accelerate the patient's recovery by introducing the application of acupuncture in pre-operation, during operation, and post-operation.

Data sources:

Literature cited in this review was retrieved from PubMed, Web of Science, and China National Knowledge Infrastructure (CNKI) and was primarily published in English or Chinese from 2010 to 2018, with keywords of “acupuncture,” “electroacupuncture,” “perioperative period,” “sedation,” “analgesia,” and “recovery.” Relevant citations in the retrieved articles were also screened to include more data.

Study selection:

All retrieved literature was scrutinized, most typical articles related on perioperative acupuncture application in clinical study were reviewed.

Results:

Acupuncture could relieve anxiety and stress during the preoperative stage. It reduces the usage of narcotics and stress response, and maintains the respiratory stability and homeostasis during surgery. It also exerts a protective effect on vital organs, and during the postoperative stages, enhances the recovery while effectively alleviating the postoperative pain. This phenomenon prevents common postoperative discomforts such as nausea and vomiting. In addition, it might improve the patients’ long-term prognosis.

Conclusions:

The novel concept “perioperative acupuncture medicine” is to focus on the optimal treatment in the perioperative period of surgical patients. The review reveals the important role of acupuncture in enhancing rapid recovery of patients during the perioperative period.

The Effectiveness of Acupuncture for Osteoporosis: A Systematic Review and Meta-Analysis

To summarize the existing evidence and evaluate the efficacy of acupuncture as a clinical treatment for osteoporosis. Six English and four Chinese databases were searched from their inception to April 2017. Randomized controlled trials were included, in which warm acupuncture, needling or electroacupuncture were compared with sole Western medicine with osteoporosis. All the data were assessed and extracted by two authors independently. The bias risk assessment recommended by the Cochrane Collaboration’s tool was used to assess the quality of the selected studies. This meta-analysis was conducted by using RevMan 5.3. Pooled analyses were calculated by standardized mean difference (SMD) and 95% confidence interval (CI). Heterogeneity was assessed by I2 test. Thirty-five studies involving 3014 patients were located. Meta-analysis showed that warm acupuncture could increase the bone mineral density of lumar (SMD [Formula: see text] 0.93, 95% CI [Formula: see text] 0.65, 1.21, [Formula: see text][Formula: see text]0.00001) and femur (MD[Formula: see text][Formula: see text][Formula: see text]0.11, 95% CI[Formula: see text][Formula: see text][Formula: see text]0.05, 0.16, P[Formula: see text][Formula: see text][Formula: see text]0.0002), the level of serum calcium (MD[Formula: see text][Formula: see text][Formula: see text]0.18, 95% CI[Formula: see text][Formula: see text][Formula: see text]0.13, 0.24, [Formula: see text][Formula: see text]0.00001) and estradiol (SMD[Formula: see text][Formula: see text][Formula: see text]0.65, 95% CI[Formula: see text][Formula: see text][Formula: see text]0.32, 0.98, P[Formula: see text][Formula: see text][Formula: see text]0.0001), relieve pain (MD[Formula: see text][Formula: see text][Formula: see text]–1.64, 95% CI[Formula: see text][Formula: see text][Formula: see text]–2.69, –0.59, P[Formula: see text][Formula: see text][Formula: see text]0.002), decrease the level of serum alkaline phosphatase (MD[Formula: see text][Formula: see text][Formula: see text]–7.8, 95% CI[Formula: see text][Formula: see text][Formula: see text]–14.17, –0.84, P [Formula: see text] 0.03) compared with sole Western medicine. Electroacupuncture could relieve pain (MD[Formula: see text][Formula: see text] –1.32, 95% CI[Formula: see text][Formula: see text][Formula: see text]–2.15, –0.48, P[Formula: see text][Formula: see text][Formula: see text]0.002), increase the level of serum calcium (MD[Formula: see text][Formula: see text][Formula: see text]–0.12, 95% CI [Formula: see text] –0.16,-0.09, [Formula: see text][Formula: see text]0.00001) and decrease the level of serum alkaline phosphatase (MD [Formula: see text] –3.63, 95% CI [Formula: see text] –6.60, –0.66, P [Formula: see text] 0.02) compared with sole Western medicine. Needling could relieve pain (MD [Formula: see text] –2.27, 95% CI [Formula: see text] –3.11, –1.43, [Formula: see text][Formula: see text]0.00001) compared with sole Western medicine. This present systematic review indicated that acupuncture could be an effective therapy for treating osteoporosis. Warm acupuncture seemed to more effective than electroacupuncture and needling for osteoporosis in comparison to sole Western medicine.