Low-frequency electroacupuncture improves disordered hepatic energy metabolism in insulin-resistant Zucker diabetic fatty rats via the AMPK/mTORC1/p70S6K signaling pathway

2022 ◽  
pp. 096452842110703
Author(s):  
Xiao-xiao Liu ◽  
Li-zhi Zhang ◽  
Hai-hua Zhang ◽  
Lan-feng Lai ◽  
Yi-qiao Wang ◽  
...  

Background and aim: Disordered hepatic energy metabolism is found in obese rats with insulin resistance (IR). There are insufficient experimental studies of electroacupuncture (EA) for IR and type 2 diabetes mellitus (T2DM). The aim of this study was to probe the effect of EA on disordered hepatic energy metabolism and the adenosine monophosphate (AMP)-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (mTORC1)/ribosomal protein S6 kinase, 70-kDa (p70S6K) signaling pathway. Methods: Zucker Diabetic Fatty (ZDF) rats were randomly divided into three groups: EA group receiving EA treatment; Pi group receiving pioglitazone gavage; and ZF group remaining untreated (n = 8 per group). Inbred non-insulin-resistant Zucker lean rats formed an (untreated) healthy control group (ZL, n = 8). Fasting plasma glucose (FPG), fasting insulin (FINS), C-peptide, C-reactive protein (CRP) and homeostatic model assessment of insulin resistance (HOMA-IR) indices were measured. Hematoxylin–eosin (H&E) staining was used to investigate the liver morphologically. The mitochondrial structure of hepatocytes was observed by transmission electron microscopy (TEM). Western blotting was adopted to determine protein expression of insulin receptor substrate 1 (IRS-1), mTOR, mTORC1, AMPK, tuberous sclerosis 2 (TSC2) and p70S6K, and their phosphorylation. RT-PCR was used to quantify IRS-1, mTOR, mTORC1, AMPK and p70S6K mRNA levels. Results: Compared with the ZF group, FPG, FINS, C-peptide, CRP and HOMA-IR levels were significantly reduced in the EA group ( p < 0.05, p < 0.01). Evaluation of histopathology showed improvement in liver appearances following EA. Phosphorylation levels of AMPK, mTOR and TSC2 decreased, and IRS-1 and p70S6K increased, in hepatocytes of the ZF group, while these negative effects appeared to be alleviated by EA. Conclusions: EA can effectively ameliorate IR and regulate energy metabolism in the ZDF rat model. AMPK/mTORC1/p70S6K and related molecules may represent a potential mechanism of action underlying these effects.

2009 ◽  
Vol 94 (11) ◽  
pp. 4499-4507 ◽  
Author(s):  
David M. Selva ◽  
Albert Lecube ◽  
Cristina Hernández ◽  
Juan A. Baena ◽  
José M. Fort ◽  
...  

Context: Zinc-α2 glycoprotein (ZAG) has been proposed as a new candidate in the pathogenesis of obesity, but most of the information stems from studies performed in rodents and in vitro assays. Objective: The main aim of the study was to compare serum levels of ZAG and its expression (mRNA levels and protein) in adipose tissue and the liver between obese and nonobese subjects. The relationship between ZAG and insulin resistance was also explored. Design: This was a case-control study. Setting: The study was conducted at a university referral center. Patients and Methods: Samples of serum, sc adipose tissue (SAT), visceral adipose tissue (VAT), and liver were obtained from 20 obese subjects during bariatric surgery. Samples from 10 nonobese patients matched by age and gender were used as a control group. Serum ZAG levels were determined by ELISA. ZAG mRNA levels were measured by real-time PCR and protein content by Western blot. The effect of insulin on liver production of ZAG was assessed using HepG2 cultures. Results: Serum concentration of ZAG (micrograms per milliliter) was significantly lower in obese subjects (40.87 ± 10.45 vs. 63.26 ± 16.40; P = 0.002). ZAG expression was significantly lower in the adipose tissue (SAT and VAT) and liver of obese patients than in control subjects. Significant negative correlations between body mass index and circulating ZAG (r = −0.65, P &lt; 0.001) as well as between body mass index and mRNA ZAG levels in SAT (r = −0.68, P &lt; 0.001) and VAT were detected (r = −0.64, P &lt; 0.001). No relationship was found between ZAG and homeostasis model assessment for insulin resistance and insulin had no effect on ZAG production in vitro. Conclusion: A down-regulation of ZAG in SAT, VAT, and liver exists in obese patients but seems unrelated to insulin resistance. A downregulation of zinc-α2 glycoprotein in adipose tissue and liver exists in obese patients, and it is unrelated to insulin resistance.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Afsaneh Talaei ◽  
Zahra Adgi ◽  
Mahnaz Mohamadi Kelishadi

Background and Objectives. Polycystic ovary syndrome (PCOS) and idiopathic hirsutism (HI) are the two most common causes of hirsutism. Insulin resistance plays a key role in PCOS, but there are not enough data showing that patients with HI also have insulin resistance. This study was designed to evaluate the presence of insulin resistance in women with HI.Methods. Based on a cross-sectional study, two groups of age-BMI matched, hirsute women were compared to age-BMI matched, nonhirsute women. Sixty nonobese women with PCOS, thirty nonobese women with HI, and sixty nonobese control women were included in the study. Samples of hormones including androgens were measured. Insulin resistance based on homeostasis model assessment of insulin resistance (HOMA-IR) was compared between three groups by the Kruskal-Wallis test.Results. Patients with PCOS had significantly higher basal insulin level (16.04±1.4versus7.32±6.85 μIu/mL) and HOMA-IR score (3.7±3.36versus1.75±1.67) than patients with HI (P  0.001). Patients with HI also had significantly higher basal insulin level and HOMA-IR score than control group (P  0.001).Conclusion. Our data suggest that both PCOS and HI are associated with insulin resistance and these patients are more insulin resistant than healthy control people.


2016 ◽  
Vol 47 (6) ◽  
pp. 1718-1726 ◽  
Author(s):  
Oscar L. Llanos ◽  
Panagis Galiatsatos ◽  
Edmarie Guzmán-Vélez ◽  
Susheel P. Patil ◽  
Philip L. Smith ◽  
...  

Insulin resistance is associated with sleep apnoea, leading us to hypothesise that it is also associated with elevations in pharyngeal collapsibility, even in the absence of sleep apnoea.90 bariatric patients were characterised for sleep apnoea, pharyngeal collapsibility and insulin resistance. Patients with a respiratory disturbance index (RDI) >10 events·h−1, diabetes mellitus, tonsillar hypertrophy and pulmonary disease were excluded. The remaining 14 females underwent collapsibility measurements (passive critical pressure, Pcritp) during non-rapid eye movement sleep. The homeostasis model assessment (HOMA) index, a measure of insulin resistance, was derived from measurements of fasting glucose and insulin levels, and compared to Pcritp.Groups with high Pcritp compared to low Pcritp did not differ in age, body mass index or RDI. HOMA and insulin were elevated in the high Pcritp group compared to the low Pcritp group (p<0.02). Pcritp correlated with HOMA (Spearman's ρ=0.565, 95% CI 0.104–0.862; p=0.035) and insulin (Spearman's ρ=0.609 95% CI 0.196–0.835; p=0.021).Obese insulin-resistant subjects without frank diabetes or sleep apnoea demonstrate preclinical elevations in pharyngeal collapsibility, which may increase their susceptibility to sleep apnoea. Our findings suggest that insulin resistance could play a significant role in sleep apnoea pathogenesis by generating requisite elevations in pharyngeal collapsibility.


Genes ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 410 ◽  
Author(s):  
Daniel Castellano-Castillo ◽  
Isabel Moreno-Indias ◽  
Jose Carlos Fernandez-Garcia ◽  
Mercedes Clemente-Postigo ◽  
Manuel Castro-Cabezas ◽  
...  

Epigenetic marks, and especially DNA methylation, are becoming an important factor in obesity, which could help to explain its etiology and associated comorbidities. Adipose tissue, now considered as an important endocrine organ, produces complement system factors. Complement component 3 (C3) turns out to be an important protein in metabolic disorders, via either inflammation or the C3 subproduct acylation stimulating protein (ASP) which directly stimulates lipid storage. In this study, we analyze C3 DNA methylation in adipose tissue from subjects with a different grade of obesity. Adipose tissue samples were collected from subjects with a different degree of obesity determined by their body mass index (BMI) as: Overweight subjects (BMI ≥ 25 and <30), obese class 1/2 subjects (BMI ≥ 30 and <40) and obese class 3 subjects (BMI ≥ 40). C3 DNA methylation was measured for 7 CpGs by pyrosequencition using the Pyromark technology (Qiagen, Madrid Spain). C3 messenger RNA (mRNA) levels were analyzed by pre-designed Taqman assays (Applied biosystems, Foster City, CA, USA) and ASP/C3a was measured using a ELISA kit. The data were analyzed using the statistic package SPSS. C3 DNA methylation levels were lower in the morbid obese group. Accordingly, C3 methylation correlated negatively with BMI and leptin. However, C3 mRNA levels were more associated with insulin resistance, and positive correlations with insulin, glucose and homeostasis model assessment-estimated insulin resistance (HOMA-IR) existed. ASP correlated negatively with high density lipoprotein (HDL) cholesterol. C3 methylation levels were associated to adiposity variables, such as BMI and leptin, while the C3 mRNA levels were associated to glucose metabolism.


2012 ◽  
Vol 120 (02) ◽  
pp. 84-88 ◽  
Author(s):  
S. Chen ◽  
X. Zhuang ◽  
Y. Liu ◽  
A. Sun ◽  
C. Chen

AbstractLipin1, a lately indentified adipokine, may link obesity with insulin resistance and diabetes. The present study aimed to investigate the changes and significance of lipin1 expression and lipin1-AMPK signaling in diet-induced hepatic insulin resistance.24 4-week-old Male Wistar rats were randomly divided into 2 groups: (1) control group (CO), (2) high-fat diet group (HF). Insulin sensitivity was evaluated by hyperinsulinemic-euglycemic clamp technique. The mRNA levels of α1 and α2 subunit of AMPKα as well as Lipin1 were measured using Real-time RT-PCR. The activities of AMPKα and Akt were evaluated by detection of p-AMPKα (Thr-172) and p-Akt (ser473) by Western blot.After treatment of 4 months, HF group showed significantly increased levels of body weight, fasting plasma glucose and insulin levels; Plasma and liver total cholesterol (TC), triglycerides (TG) levels were also markedly elevated; Lipin1 expression at both mRNA and protein levels were significantly deceased. Compared with CO group, the mRNA and protein levels of AMPKα1 and AMPKα2 were not changed, whereas the p-AMPK (Thr-172) and p-AKT (ser473) levels in liver were significantly decreased in HF group.These findings indicated that the decrease in lipin1 expression and AMPKα activation may contribute to hepatic insulin resistance in diet-induced obese rats.


1998 ◽  
Vol 275 (3) ◽  
pp. R788-R792 ◽  
Author(s):  
Prasad V. G. Katakam ◽  
Michael R. Ujhelyi ◽  
Margarethe E. Hoenig ◽  
Allison Winecoff Miller

The insulin-resistant (IR) syndrome may be an impetus for the development of hypertension (HTN). Unfortunately, the mechanism by which this could occur is unclear. Our laboratory and others have described impaired endothelium-mediated relaxation in IR, mildly hypertensive rats. The purpose of the current study is to determine if HTN is most likely a cause or result of impaired endothelial function. Sprague-Dawley rats were randomized to receive a fructose-rich diet for 3, 7, 10, 14, 18, or 28 days or were placed in a control group. The control group received rat chow. After diet treatment, animals were instrumented with arterial cannulas, and while awake and unrestrained, their blood pressure (BP) was measured. Subsequently, endothelium-mediated relaxation to acetylcholine was determined (in vitro) by measuring intraluminal diameter of phenylephrine-preconstricted mesenteric arteries (∼250 μM). Serum insulin levels were significantly elevated in all groups receiving fructose feeding compared with control, whereas there were no differences in serum glucose levels between groups. Impairment of endothelium-mediated relaxation starts by day 14 [mean percent maximal relaxation (Emax): 69 ± 10% of baseline] and becomes significant by day 18 (Emax: 52 ± 11% of baseline; P < 0.01). However, the mean BP (mmHg) does not become significantly elevated until day 28 [BP: 132 ± 1 ( day 28) vs. 116 ± 3 (control); P < 0.05]. These findings demonstrate that both IR and endothelial dysfunction occur before HTN in this model and suggest that endothelial dysfunction may be a mechanism linking insulin resistance and essential HTN.


2017 ◽  
Vol 10 (1) ◽  
pp. 18-23
Author(s):  
Tahmina Akter ◽  
Md. Reza Bin Zaid ◽  
Zeenat Farzana Rahman ◽  
M. Abu Sayeed

Background: Acanthosis nigricans (AN) is known to be associated with obesity, insulin resistance (IR) and other systemic morbid conditions. Proper treatment modalities of AN has not been established yet. Metformin may have some therapeutic effects on AN by reducing IR. Objective of the study was to examine the effect of metformin on AN in insulin resistant cases.Methodology and Results: This prospective, controlled trial was conducted in Dermatology OPD of BIRDEM General Hospital, Dhaka from September 2012 to August 2013. All the participants of the study had clinical presentation of AN on different anatomic locations such as neck, axilla, elbow, knuckle and knee and biochemical evidence of IR. Participants were of either sex with age ranging from 18 to 80 years. Any case who had contraindications to metformin therapy were excluded. Severity of AN was examined and assessed by a quantitative scale for measuring acanthosis nigricans. After detecting IR by Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), cases and controls were selected by random sampling method. Randomization was done for metformin in ratio of 2:1. Every third patient was a control. Forty study participants were assigned to receive tablet metformin 500mg thrice daily after meal for three months and twenty control participants were continued on their existing therapy. To maintain a static metabolic status, patients were allowed to remain with their previous diet and lifestyle habit. After 3 months of metformin therapy, improvement was assessed and was compared with control group.Mean age of the participants in case of male: 19.75±2.36 and in case of female: 26.58±9.38, M:F= 1:14, BMI of male: 32.15±4.15 and female: 33.18± 8.05. Mean baseline neck severity score of AN: 3.57 ± 0.78 and after metformin therapy: 2.65 ± 1.02, t-test value: 4.53. Baseline neck texture score of AN: 1.87±0.80, after metformin therapy: 1.25 ± 0.86, ttest value: 3.30. Baseline AN on axilla: 3.05 ± 0.94, after metformin therapy: 2.10 ± 0.98, ttest value: 4.56. Significant improvement of AN was observed clinically on neck and axilla (P<0.005) when compared with control. However, in case of AN on knuckle, elbow and knee, improvement rates were not statistically significant. No side-effect except nausea in 4 patients was reported during study period.Conclusion: Metformin therapy for AN with IR had a significant beneficial effect clinically and was safe and well-tolerated. The effect was more pronounced in neck and axilla.IMC J Med Sci 2016; 10(1): 18-23


Life ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 127 ◽  
Author(s):  
Federica Vinciguerra ◽  
Andrea Tumminia ◽  
Roberto Baratta ◽  
Alfredo Ferro ◽  
Salvatore Alaimo ◽  
...  

Obesity represents a major risk factor for metabolic disorders, but some individuals, “metabolically healthy” (MHO), show less clinical evidence of these complications, in contrast to “metabolically unhealthy” (MUO) individuals. The aim of this cross-sectional study is to assess the prevalence of the MHO phenotype in a cohort of 246 overweight/obese Italian children and adolescents, and to evaluate their characteristics and the role of insulin resistance. Homeostasis model assessment–insulin resistance (HOMA-IR), insulin sensitivity index (ISI), insulinogenic index (IGI) and disposition index (DI) were all calculated from the Oral Glucose Tolerance Test (OGTT). MHO was defined by either: (1) HOMA-IR < 2.5 (MHO-IRes), or (2) absence of the criteria for metabolic syndrome (MHO-MetS). The MHO prevalence, according to MHO-MetS or MHO-IRes criteria, was 37.4% and 15.8%, respectively. ISI was the strongest predictor of the MHO phenotype, independently associated with both MHO-IRes and MHO-MetS. The MHO-MetS group was further subdivided into insulin sensitive or insulin resistant on the basis of HOMA-IR (either < or ≥ 2.5). Insulin sensitive MHO-MetS patients had a better metabolic profile compared to both insulin resistant MHO-MetS and MUO-MetS individuals. These data underscore the relevance of insulin sensitivity to identifying, among young individuals with overweight/obesity, the ones who have a more favorable metabolic phenotype.


Biomolecules ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 97 ◽  
Author(s):  
Esra Demir ◽  
Nazmiye Harmankaya ◽  
İrem Kıraç Utku ◽  
Gönül Açıksarı ◽  
Turgut Uygun ◽  
...  

In this study, it was aimed to investigate the relationship between the epicardial adipose tissue thickness (EATT) and serum IL-17A level insulin resistance in metabolic syndrome patients. This study enrolled a total of 160 subjects, of whom 80 were consecutive patients who applied to our outpatient clinic and were diagnosed with metabolic syndrome, and the other 80 were consecutive patients who were part of the control group with similar age and demographics in whom the metabolic syndrome was excluded. The metabolic syndrome diagnosis was made according to International Diabetes Federation (IDF)-2005 criteria. EATT was measured with transthoracic echocardiography (TTE) in the subjects. IL-17A serum levels were determined using the ELISA method. Fasting blood glucose, HDL, triglyceride, and fasting insulin levels were significantly higher in the metabolic syndrome group compared to the control group. In addition, the metabolic syndrome group had significantly higher high-sensitivity C-reactive protein (hs-CRP) and Homeostatic Model Assessment Insulin Resistance (HOMA-IR) levels than the control group. Similarly, serum IL-17A levels were significantly elevated in the metabolic syndrome group compared to the control group statistically (p < 0.001). As well, EATT was higher in the metabolic syndrome than the control group. Conclusion: By virtue of their proinflammatory properties, EATT and IL-17 may play an important role in the pathogenesis of the metabolic syndrome.


2018 ◽  
Vol 6 (3) ◽  
pp. 511-518 ◽  
Author(s):  
Marko Kostovski ◽  
Viktor Simeonovski ◽  
Kristina Mironska ◽  
Velibor Tasic ◽  
Zoran Gucev

BACKGROUND: In the past several decades, the increasing frequency of overweight and obese children and adolescents in the world has become a public health problem. It has contributed significantly to the already high tide of diabetes, cardiovascular and cerebrovascular diseases.AIM: To investigate the frequency of insulin resistance and to evaluate the metabolic profile of insulin resistant and non-insulin resistant obese children and adolescents.SUBJECTS AND METHODS: The study included 96 (45 boys, 51 girls) obese children and adolescents aged     4-17 years old (10.50 ± 2.87 years). Only participants with Body Mass Index ≥ 95 percentile were included.  We analysed sera for fasting insulin levels (FI), fasting serum triglycerides (TG), total serum cholesterol (TC), fasting plasma glucose (FPG) and plasma glucose 2 hours after the performance of the oral glucose tolerance test        (2-h G). Homeostatic model assessment for insulin resistance (HOMA-IR) index was calculated as fasting insulin concentration (microunits per millilitre) x fasting glucose concentration (millimolar)/22.5. The value of HOMA-IR above 3.16 was used as a cut-off value for both genders.RESULTS: Insulin resistance was determined in 58.33% of study participants. Insulin resistant participants had significantly higher level of 2-h G (p = 0.02), FI level (p = 0.000) as well as TG levels (p = 0.01), compared to non-insulin resistant group. Strikingly, 70.73% of the pubertal adolescents were insulin resistant in comparison to 49.09% of the preadolescents (p = 0.03). Significantly higher percentage of insulin-resistant participants were girls (p = 0.009). Moreover, a higher percentage of the girls (70.59%) than boys (44.44%) had HOMA-IR above 3.16 and had elevated FI levels (70.59% vs 48.89%). The difference in the frequency of insulin resistance among obese versus severely obese children and adolescents was not significant (p = 0.73, p > 0.05). Our study results also showed positive, but weak, correlation of HOMA-IR with age, FPG, TG and BMI of the participants (p < 0.05).CONCLUSION: Higher percentage of insulin-resistant participants was of female gender and was adolescents. In general, insulin resistant obese children and adolescents tend to have a worse metabolic profile in comparison to individuals without insulin resistance. It is of note that the highest insulin resistance was also linked with the highest concentrations of triglycerides.


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