Effect of acupuncture on serum PYY and nesfatin-1 in obese patients with insulin resistance

Liu Mei-zhang (劉美章), Liu Yong-tao (劉永濤), Yang Li-bai (楊禮白)

Huai’an Hospital of Traditional Chinese Medicine, Jiangsu Province, Huai’an 223001, China

Abstract

Keywords: Acupuncture Therapy; Obesity; Diet, Reducing; Insulin Resistance; Body Mass Index; Peptide YY; Nesfatin-1

Obesity is a chronic metabolic disease caused by multiple factors that result in excessive total and (or)localized body fat[1]. According to a survey, the rates of overweight and obesity among adult residents in China are 30.1% and 11.9%, respectively, and 9.6% and 6.2%among adolescents, respectively[2]. With the improvement of living standards and major changes in people's dietary structure and living habits, the incidence of obesity has shown a linear increase and it has become a worldwide public health problem[3].

Obese patients are mostly associated with insulin resistance (IR), i.e., decreased sensitivity of target organs to insulin. Studies have shown that about 64.9% of male obese patients have IR and 73.2% of female obese patients have IR[4]. After IR occurs, the sensitivity of adipose tissue to insulin decreases, peripheral fat hydrolysis is aggravated, and the level of free fatty acids increases, which is then esterified into more triglyceride(TG) and therefore aggravate lipid metabolism disorders.Obesity, IR, and lipid metabolism disorders gradually form a vicious circle[5]. In addition, IR is also the common pathological basis of several metabolic diseases such as hypertension, atherosclerosis, and polycystic ovary syndrome[6]. Currently, behavioral interventions such as diet control and aerobic exercise are the preferred treatment options for obesity with IR, but require longterm adherence. Pharmacological treatments such as metformin have risks of adverse effects such as gastrointestinal reactions and liver damage, and surgical treatment has multiple complications such as infection and organ adhesions[7].

In recent years, acupuncture has achieved satisfactory efficacy in the treatment of obesity and diabetes, and can improve the body’s glucolipid metabolism without significant adverse effects[8-9], showing good prospects.Based on this, this study used acupuncture to treat obese patients with IR and observed its effect on serum peptide YY (PYY) and nesfatin-1 in the patients, which is reported as follows.

1 Clinical Materials

1.1 Diagnostic criteria in Western medicine

The diagnostic criteria for obesity were established with reference to theChinese Guidelines for the Prevention and Control of Overweight and Obesity in Adults[10]: body mass index (BMI) ≥28 kg/m2, with a waist circumference ≥85 cm in males and ≥80 cm in females.

Referring to theChinese Guidelines for the Prevention and Control of Type 2 Diabetes[11], the diagnostic criteria for IR were established: homeostasis model assessment for insulin resistance (HOMA-IR) ≥2.68.

1.2 Syndrome differentiation criteria in traditional Chinese medicine (TCM)

Referring to the TCM syndrome differentiation criteria for obesity with phlegm-dampness due to spleen deficiency in theGuiding Principles for Clinical Study of New Chinese Medicines[12]. Primary symptoms: obesity;fatigue; weakness; heaviness in the limbs. Secondary symptoms: abdominal fullness; poor appetite; loose stools; a pale, enlarged, and tooth-marked tongue with thin and greasy coating; deep and thready pulse.

1.3 Inclusion criteria

Met the Western medical diagnostic criteria for obesity and IR; met the TCM syndrome differentiation criteria for phlegm-dampness due to spleen deficiency;aged between 20 and 60 years; had not taken any weight-loss drugs or health products in the past one month; provided written informed consent.

1.4 Exclusion criteria

Diagnosed diabetes mellitus; secondary obesity due to hypothyroidism, hypogonadism, hypercortisolism,etc.; pregnant or lactating women; those with severe combined cardiovascular, immune, endocrine, and other underlying diseases; those with mental disorders or mental retardation.

1.5 Criteria for elimination and dropout

Those who experienced serious adverse reactions during the trial; those who used other drugs without authorization; those who voluntarily requested to withdraw from this trial; those with incomplete information, which affected the judgment of efficacy.

1.6 Statistical analysis

SPSS version 18.0 statistical software was used for statistical analysis. Counting data were analyzed using the Chi-square test. The measurement data that met normality and homoscedasticity were expressed as mean ± standard deviation (±sand analyzed byt-test.Measurement data that did not meet normality or homoscedasticity were tested using the nonparametric test.P<0.05 was taken as statistically significant.

1.7 General data

Ninety-eight cases of obese patients with IR admitted to Huai'an Hospital of Traditional Chinese Medicine,Jiangsu Province between January 2016 and December 2019 were selected and divided into a control group and an observation group according to the random number table method, with 49 cases in each group. Among them,two cases in the control group and three cases in the observation group withdrew from the trial halfway because they were away for work and study. Finally, 47 cases in the control group and 46 cases in the observation group completed the trial. There were no statistically significant differences between the two groups in gender, age, or disease duration (P>0.05),(Table 1).

Table 1. Baseline characteristics of the two groups

2 Treatment Methods

2.1 Control group

The control group received exercise and dietary interventions.

Exercise intervention: brisk walking for 30 min, five times a week.

Dietary intervention: daily caloric intake was≤125.7 kJ/(kg·bw); high-calorie and high-sugar foods such as carbonated drinks, barbecue and fried foods were prohibited; no more food was eaten after 22:00.

During the trial, patients were given adequate health education and informed that behavioral interventions such as dietary control and aerobic exercise were the preferred regimens for the treatment of obesity with IR to ensure compliance.

2.2 Observation group

The observation group received add-on acupuncture therapy to the exercise and dietary interventions.

Acupoints: Zhongwan (CV 12), bilateral Tianshu (ST 25),Yinlingquan (SP 9), Zusanli (ST 36), Fenglong (ST 40),Sanyinjiao (SP 6), and Quchi (LI 11).

Methods:Hwato brand disposable sterile acupuncture needles of 0.25 mm in diameter and 40 mm in length (Suzhou Medical Appliance Factory Co., Ltd.,China) were used for acupuncture. The patient took a supine position and the local skin was exposed. After routine disinfection with 75% alcohol cotton balls, the acupuncturist inserted the needles by nail-pressing method. The selected acupoints were needled perpendicularly for about 1 Cun. After achieving needling sensation (Deqi), all acupoints were stimulated with even reinforcing-reducing manipulation, and the needles were retained for 30 min. The acupuncture treatment was performed once every other day for three months.

3 Observation of Therapeutic Efficacy

3.1 Observation items

3.1.1 BMI and body fat percentage

Before and after treatment, weight, height, and body fat percentage were measured in both groups and BMI was calculated. BMI = Weight ÷ Height2.

3.1.2 Serum TG and total cholesterol (TC) levels

Before and after treatment, fasting venous blood was drawn from the patients and the serum TG and TC levels were detected using a fully automated biochemical analyzer.

3.1.3 Fasting insulin (FINS), fasting plasma glucose(FPG) and HOMA-IR

Before and after treatment, fasting venous blood was drawn from the patients. FINS was detected using a fully automated immunoluminescence analyzer, FPG was measured using a fully automated biochemical analyzer,and HOMA-IR was calculated. HOMA-IR = FINS × FPG ÷

22.5.

3.1.4 Serum PYY and nesfatin-1 levels

Before and after treatment, fasting venous blood was drawn from the patients. The serum PYY and nesfatin-1 levels were detected by enzyme-linked immunosorbent assay.

3.2 Criteria for therapeutic efficacy

The degree of BMI reduction was used as the primary basis for judging the efficacy[10].Markedly effective: BMI reduction ≥4 kg/m2.Effective: BMI reduction 2-4 kg/m2.Invalid: BMI reduction <2 kg/m2.

3.3 Results

3.3.1 Comparison of the therapeutic efficacy

The total effective rate was higher in the observation group than in the control group (89.1% versus 59.6%,χ2=9.12,P=0.002). See Table 2 for details.

3.3.2 Comparisons of the BMI and body fat percentage

Before treatment, the BMI and body fat percentage did not differ significantly between the two groups(P>0.05). After treatment, the BMI and body fat percentage significantly decreased in both groups(P<0.05), and were significantly lower in the observation group than those in the control group (P<0.05). See Table 3 for details.treatment (P<0.05), and were lower than those in the control group (P<0.05). See Table 5 for details.

Table 2. Comparison of the total effective rate between the two groups (case)

Table 3. Comparisons of the BMI and body fat percentage between the two groups ( ±s

Table 3. Comparisons of the BMI and body fat percentage between the two groups ( ±s

Note: BMI=Body mass index; compared with the same group before treatment, 1) P<0.05; compared with the control group after treatment, 2) P<0.05

Group n Time BMI (kg/m2) Body fat percentage (%)Observation 46 Before treatment 30.46±1.53 35.76±2.49images/BZ_35_1036_2883_1036_2888.pngAfter treatment 27.04±1.091)2) 31.69±2.581)2)Control 47 Before treatment 30.19±1.36 36.75±2.68 After treatment 29.60±1.181) 33.71±2.591)

3.3.5 Comparisons of the serum PYY and nesfatin-1 levels

Before treatment, the serum PYY and nesfatin-1 levels did not differ significantly between the two groups(P>0.05). The serum PYY and nesfatin-1 levels of the control group were not significantly different from those before treatment (P>0.05). The serum PYY and nesfatin-1 levels of the observation group increased significantly after treatment (P<0.05), and were higher than those in the control group (P<0.05). See Table 6 for details.

Table 4. Comparisons of the serum TG and TC levels between the two groups ( ±s mmol/L)

Table 4. Comparisons of the serum TG and TC levels between the two groups ( ±s mmol/L)

Note: TG=Triglyceride; TC=Total cholesterol; compared with the same group before treatment, 1) P<0.05; compared with the control group after treatment, 2) P<0.05

Group n Time TG TC Observation 46 Before treatment 2.73±0.89 4.39±0.68 After treatment 1.74±0.441)2) 3.42±0.611)2)Control 47 Before treatment 2.64±0.94 4.24±0.74 After treatment 2.15±0.791) 3.83±0.661)

3.3.3 Comparisons of the serum TG and TC levels

Before treatment, the serum TG and TC levels did not differ significantly between the two groups (P>0.05).After treatment, the serum TG and TC levels decreased significantly in both groups (P<0.05), and were significantly lower in the observation group than those in the control group (P<0.05). See Table 4 for details.

3.3.4 Comparisons of the FINS, FPG and HOMA-IR

Before treatment, the FINS, FPG, and HOMA-IR did not differ significantly between the two groups (P>0.05). The FINS, FPG, and HOMA-IR of the control group were not significantly different from those before treatment(P>0.05). The FINS, FPG, and HOMA-IR of the observation group decreased significantly after

Table 5. Comparisons of the FINS, FPG and HOMA-IR between the two groups ( ±s

Table 5. Comparisons of the FINS, FPG and HOMA-IR between the two groups ( ±s

Note: FINS=Fasting insulin; FPG=Fasting plasma glucose; HOMA-IR=Homeostasis model assessment for insulin resistance; compared with the same group before treatment, 1) P<0.05; compared with the control group after treatment, 2) P<0.05

Group n Time FINS (IU/mL) FPG (mmol/L) HOMA-IR Observation 46 Before treatment 21.53±3.00 5.39±0.45 5.15±0.79 After treatment 17.05±2.591)2) 4.85±0.421)2) 3.68±0.701)2)Control 47 Before treatment 20.81±2.99 5.34±0.42 4.92±0.73 After treatment 20.79±2.75 5.25±0.43 4.85±0.74

Table 6. Comparison of the serum PYY and nesfatin-1 levels between the two groups ( ±s

Table 6. Comparison of the serum PYY and nesfatin-1 levels between the two groups ( ±s

Note: PYY=Peptide YY; compared with the same group before treatment, 1) P<0.05; compared with the control group after treatment,2) P<0.05

Group n Time PYY (ng/L) Nesfatin-1 (ng/mL)Observation 46 Before treatment 128.81±5.46 1.19±0.42 After treatment 138.50±7.071)2) 1.61±0.491)2)Control 47 Before treatment 130.89±6.52 1.13±0.39 After treatment 130.26±5.92 1.28±0.40

4 Discussion

The mechanisms of obesity leading to IR are currently thought to include abnormal fat deposition, increased secretion of inflammatory factors, and abnormal secretion of adipose tissue hormones[13-15]. Obese patients have significantly higher levels of free fatty acids,which are deposited in and fattening islet cells, affecting insulin receptor signaling pathways, and impeding glucose uptake and utilization[13]. Obese patients have significantly increased fat contents in the muscles and cells, causing a chronic inflammatory response with significant increases in inflammatory factors such as interleukin-6 and tumor necrosis factor-α, which in turn activates the JNK/SAPK pathway or the IKKβ/NF-κB pathway and inhibits insulin signaling pathways[14].Obese patients have abnormal adipokine secretion and disturbed levels of leptin, lipocalin, and resistin, which affects glucose transport and insulin synthesis and secretion, ultimately leading to hyperinsulinemia and IR[15].

PYY is an endogenous peptide hormone secreted mainly by cells in the ileum, colon, and rectum. PYY can enter the nerve center through the blood-brain barrier,inhibit the activity of neuropeptide Y neurons in the arcuate nucleus, reduce neuropeptide Y release, and also activate pro-opiomelanocortin neurons to suppress appetite, delay gastrointestinal emptying, enhance satiety, and control body weight[16]. Studies have shown that the fasting serum PYY level is significantly lower in obese patients than in normal controls and the PYY level is significantly negatively correlated with BMI, suggesting that endogenous PYY deficiency may be associated with obesity[17]. PYY also inhibits insulin secretion and improves IR by decreasing the cyclophilin level and acting on islet Y1 receptor. Cui T,et al[18]tested the serum PPY level in patients with primary diagnosis of type 2 diabetes and found that patients had a significantly lower level of blood PPY secretion after fasting and standard meals, and the peak secretion disappeared half an hour after meals. It could be seen that a low level of PPY might promote the development and progression of obesity and IR at the same time.

Nesfatin-1 is a food intake inhibitory factor that is widely distributed in digestion-related central and peripheral tissues. An animal experiment showed that nesfatin-1 injection significantly reduced food intake in rats. The feeding inhibition effect was dose-dependent and disappeared after nesfatin-1 antibody injection[19].Sun WJ[20]compared the serum nesfatin-1 level between the obese patients and healthy subjects, and found that the fasting serum nesfatin-1 level was significantly lower in the obese patients than in healthy subjects and was negatively correlated with BMI and HOMA-IR. This suggests that nesfatin-1 is not only involved in the development of obesity but also associated with insulin sensitivity. Yang M,et al[21]found that intracerebroventricular injection of nesfatin-1 into animals could phosphorylate the insulin receptor signaling pathway to reduce gluconeogenesis, promote glucose utilization in peripheral tissues, improve insulin sensitivity, and maintain glucose homeostasis. Hence,nesfatin-1 may be closely related to obesity and IR.

The basic pathogenesis of obesity is that the spleen fails in the function of transportation and transformation,and phlegm-dampness generates internally, which is mostly the evidence of deficiency in the root cause and excess in the symptoms. If the function of spleen and stomach is out of order, they will not perform well in receiving and transporting. Then the water and grain essence cannot be transported and distributed,therefore staying stagnant to form phlegm and dampness distributed in muscles to develop obesity[8].Phlegm-dampness and turbid-fat accumulate in the abdomen, retained for a long time, turning into heat that burns fluids internally, thereby developing into IR[22]. The pathogenesis of obesity with IR is dominated by phlegmdampness stagnation, and the syndrome type is mostly phlegm-dampness due to spleen deficiency. The treatment should be strengthening the spleen,reinforcing Qi, resolving phlegm, and removing dampness.

The acupuncture treatment was given to Zhongwan(CV 12), which strengthens the spleen, harmonizes the stomach, resolves dampness, relieves water, and treats digestive disorders. Tianshu (ST 25) is the Front-Mu point of the large intestine. It can regulate the middle Jiao and stomach, promote Qi, strengthen the spleen, and regulate the bowels. Yinlingquan (SP 9) is the He-Sea point of the Spleen Meridian, and can strengthen the spleen, resolve dampness, regulate Qi, and relieve turbidity. Zusanli (ST 36) is the lower He-Sea point of the stomach, and can strengthen the spleen, harmonize the stomach, transport water-dampness, and benefit Qi to resolve phlegm. Fenglong (ST 40) is the Luo-Connecting point of the Stomach Meridian, and can strengthen the spleen, resolve phlegm, and harmonize the stomach to subdue the rebellion. It is also an important point for phlegm, treating phlegm-dampness and dampness-heat trapped in the spleen. Sanyinjiao (SP 6) regulates the liver,spleen, and kidney. Quchi (LI 11) regulates the three Jiao(triple energizer), clears heat, and frees downflow. The above points work together to strengthen the spleen,resolve dampness, regulate Qi, and dispel phlegm.

The results of this study showed that the total effective rate was significantly higher in the observation group than in the control group (P<0.05). After treatment, the BMI, body fat percentage, and serum TG and TC levels significantly decreased in both groups(P<0.05), and were significantly lower in the observation group than in the control group (P<0.05). The FINS, FPG and HOMA-IR of the control group were not significantly different from those before treatment (P>0.05). The FINS,FPG and HOMA-IR of the observation group decreased significantly after treatment (P<0.05), and were lower than those in the control group (P<0.05). These suggest that acupuncture intervention for obesity with IR is effective, and it can reduce BMI, body fat percentage,blood lipids, glucose and serum insulin and improve IR.After treatment, the serum PYY and nesfatin-1 levels of the control group were not significantly different from those before treatment (P>0.05). The serum PYY and nesfatin-1 levels of the observation group increased significantly after treatment (P<0.05), and were higher than those in the control group (P<0.05). This suggests that acupuncture can increase the serum PYY and nesfatin-1 levels in obese patients with IR, and the action of acupuncture may be related to this.

In conclusion, based on exercise and dietary interventions, acupuncture is effective to treat obese patients with IR. It can reduce the BMI, body fat percentage, blood lipids, blood glucose, serum insulin level, and improve IR. The action may be associated with the up-regulation of serum PYY and nesfatin-1.

Conflict of Interest

The authors declare that there is no potential conflict of interest in this article.

Acknowledgments

There was no project fund supporting this study.

Statement of Informed Consent

Informed consent was obtained from all individual participants.

Received: 14 September 2020/Accepted: 25 December 2020