Hui-Jie Zhang

Association of Serum Irisin with Metabolic Syndrome in Obese Chinese Adults

Irisin, a recently identified novel myokine, drives brown-fat-like conversion of white adipose tissues and has been proposed to mediate beneficial effects of exercise on metabolism. Circulating irisin was significantly reduced in type 2 diabetes patients; however, no evidence is available about its association with metabolic syndrome (MetS) and effects of adiposity and muscle mass on circulating irisin have been controversial. Cross-sectional data on socio-demographic, lifestyle, clinical characteristics and serum irisin were collected for 1,115 community-living Chinese adults with central obesity. Associations of serum irisin with MetS (central obesity plus any two of the following four factors (raised blood pressure (BP), raised fasting plasma glucose (FPG), raised triglyceride (TG), and reduced HDL cholesterol) and each component of MetS were analyzed using multivariable logistic regression. Among the 1,115 obese Chinese adults with a mean age of 53.2(±7.2) years, serum irisin levels (log-transformed) were significantly reduced in subjects with MetS and raised FPG than their control groups (p = 0.034 and 0.041, respectively). After adjustment for potential confounders, serum irisin was significantly associated with reduced risks of MetS and raised FPG, with odds ratios (ORs) (95% CI) per standard deviation of log-transformed irisin of 0.796 (0.505–0.959, p = 0.027) and 0.873 (0.764–0.998, p = 0.046), respectively. Associations of irisin with raised BP, raised TG and reduced HDL were not statistically significant ((ORs) (95% CI): 0.733(0.454–1.182, p = 0.202), 0.954(0.838–1.086, p = 0.478) and 1.130(0.980–1.302, p = 0.092), respectively). Stepwise multivariable linear regression analysis showed that fasting insulin, HbA1c and albumin/globulin ratio were negatively associated with serum irisin level with statistical significance (all p-values <0.05) and waist circumference was negatively associated with serum risin with marginally statistical significance (p = 0.055). These results imply that irisin may play an important role in insulin resistance and MetS and should be confirmed in future prospective studies.

Metformin vs thiazolidinediones for treatment of clinical, hormonal and metabolic characteristics of polycystic ovary syndrome: a meta‐analysis

Objectives  Insulin‐sensitizing drugs (ISDs) have been advocated for the long‐term treatment of polycystic ovary syndrome (PCOS). It is therefore important to compare the efficacy and safety of ISDs such as metformin and thiazolidinediones (TZDs) for the treatment of this syndrome.

Puerarin improves insulin resistance and modulates adipokine expression in rats fed a high-fat diet

The link between obesity and insulin resistance largely accounts for the pathogenesis of metabolic syndrome and diabetes mellitus, in which adipokine expression plays a key role. Puerarin, a major active isoflavone extracted from the traditional Chinese medicine Radix Puerariae, has been studied for its comprehensive biological actions. However, its effect on high-fat diet (HFD)-induced insulin resistance and adipokine expression in rat has not been well investigated. In the present study, male Sprague-Dawley rats were fed on a normal control diet (NCD) or HFD for 6 weeks, followed by administration of puerarin (100 and 200 mg/kg) for up to 8 weeks. Compared to NCD, HFD feeding for 6 weeks led to increased body weight gain and impaired glucose/insulin tolerance manifested by oral glucose/intraperitoneal insulin tolerance tests in rats. These exacerbations prolonged through HFD feeding, but were effectively reversed by puerarin administration. Enzyme-linked immunosorbent assay demonstrated that, serum levels of leptin and resistin, but not that of adiponectin, were markedly augmented by HFD and retarded by puerarin treatment. Real-time reverse transcription polymerase chain reaction results showed that, in agreement with the circulating levels, mRNA expression of leptin and resistin in epididymal white adipose tissue was modified by HFD and improved by puerarin in the same pattern. Collectively, we revealed that puerarin could improve body weight gain, glucose/insulin intolerance and adipokine expression in HFD-induced insulin resistant rats, indicating its potential value for treatment of metabolic syndrome.

Chinese Lacto-Vegetarian Diet Exerts Favorable Effects on Metabolic Parameters, Intima-Media Thickness, and Cardiovascular Risks in Healthy Men

BACKGROUND To investigate whether the Chinese lacto-vegetarian diet has protective effects on metabolic and cardiovascular disease (CVD). METHODS One hundred sixty-nine healthy Chinese lacto-vegetarians and 126 healthy omnivore men aged 21-76 years were enrolled. Anthropometric indexes, lipid profile, insulin sensitivity, pancreatic β cell function, and intima-media thickness (IMT) of carotid arteries were assessed and compared. Cardiovascular risk points and probability of developing CVD in 5-10 years in participants aged 24-55 years were calculated. RESULTS Compared with omnivores, lacto-vegetarians had remarkably lower body mass index, systolic and diastolic blood pressure, and serum levels of triglyceride, total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, γ-glutamyl transferase, serum creatinine, uric acid, fasting blood glucose, as well as lower total cholesterol/high-density lipoprotein cholesterol ratio. Vegetarians also had higher homeostasis model assessment β cell function and insulin secretion index and thinner carotid IMT than the omnivores did. These results corresponded with lower cardiovascular risk points and probability of developing CVD in 5-10 years in vegetarians 24-55 years old. CONCLUSIONS In healthy Chinese men, the lacto-vegetarian diet seems to exert protective effects on blood pressure, lipid profiles, and metabolic parameters and results in significantly lower carotid IMT. Lower CVD risks found in vegetarians also reflect the beneficial effect of the Chinese lacto-vegetarian diet.

Relationship of carotid intima-media thickness and duration of vegetarian diet in Chinese male vegetarians.

ObjectiveMany studies have shown that vegetarian diet has beneficial effects on the prevention of cardiovascular diseases. However, the effect of vegetarian diet on carotid intima-media thickness (IMT), as well as the association between IMT and duration of vegetarian diet, are still unclear. The present study aims to investigate the influence of duration of vegetarian diet on cardiovascular risk factors, and more importantly on IMT among Chinese vegetarians.MethodsOne hundred and seventy-one Chinese male vegetarians were screened for metabolic profile, cardiovascular risk and carotid IMT. They were compared with 129 age-matched omnivores recruited from a community-based health project. The effects of confounding factors were adjusted by stepwise logistic regression analysis.ResultsCompared to the omnivores, the vegetarians had lower BMI, weight, systolic blood pressure and diastolic blood pressure. Also, the levels of triglyceride, total cholesterol, HDL-Cholesterol, LDL-Cholesterol, ApoA1, ApoB, uric acid, albumin and γ-glutamyltransferase were significantly reduced in vegetarians. Omnivores had significantly higher fasting blood glucose than that of vegetarians. However, there were no differences in fasting insulin, C-reactive protein and HOMA-IR between the two groups. IMT was thinner in the vegetarian group than in the omnivore group (0.59 ± 0.16 vs. 0.63 ± 0.10 cm, P < 0.05). The vegetarians were divided according to duration of vegetarian diet (< 6 years, 6 to ≤ 11 years, > 11 years), those in tertile 1 (< 6 years) and tertile 2 (6 to ≤ 11 years) had shown thinner IMT as compared to the omnivores, and tertile 3 had shown no reduction.ConclusionA decrease in multiple cardiovascular risk factors such as BMI, blood pressure and lipid profile was associated with vegetarian diet. Moreover, taking a low-calorie, low-protein, or vegetarian diet might have great beneficial effects on IMT through improved lipid profile, and the beneficial effects appeared to be correlated with the duration of vegetarian diet.

Activation of nuclear factor-kappa B pathway is responsible for tumor necrosis factor-a-induced up-regulation of endothelin B2 receptor expression in vascular smooth muscle cells in vitro

The endothelin B2 (ET(B2)) receptors are induced in vascular smooth muscle cells (VSMCs) in cardiovascular diseases. We tested if in vitro short-term exposure to the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) could up-regulate ET(B2) receptors in rat mesenteric arteries, and if this effect is through activation of intracellular nuclear factor-κB (NF-κB) pathway. The mesenteric arteries were dissected from male Sprague-Dawley rats and the endothelium was removed. The arteries were co-incubated with TNF-α in serum-free Dulbeccos modified Eagles medium. Real-time reverse transcription-PCR, Western blot and immunohistochemical staining were employed to assess the mRNA/protein expression of ET(B2) receptors and activation of NF-κB pathway. The results showed that, during organ culture, TNF-α concentration-dependently enhanced ET(B2) receptors expression at both mRNA and protein levels, paralleled with activation of NF-κB pathway in VSMC. The up-regulated ET(B2) receptor expression and NF-κB activation could be effectively suppressed by general transcriptional inhibitor actinomycin D, or either of the selective IκB kinase inhibitors wedelolactone and IMD-0354. Conclusively, the activation of intracellular NF-κB pathway is responsible for the up-regulation of ET(B2) receptors induced by short-term exposure to TNF-α. This could partly explain the toxic effects of TNF-α on VSMCs that account for cardiovascular diseases.

Intrahepatic triglyceride content is independently associated with chronic kidney disease in obese adults: A cross-sectional study

BACKGROUND Non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD) are associated with some common critical cardio-metabolic risk factors. The aim of this study was to explore the association between intrahepatic triglyceride (IHTG) content and CKD in obese subjects. METHODS A total of 1068 obese participants received anthropometric, biochemical measurements and hepatic ultrasonography. Of those, 485 participants received magnetic resonance spectroscopy ((1)H-MRS) for the determination of IHTG content. CKD was defined as a urinary albumin:creatinine ratio (UACR)≥30 mg/g and/or estimated glomerular filtration rate (eGFR)<60 mL/min per 1.73 m(2). RESULTS The prevalence of CKD was significantly higher in NAFLD subjects compared to subjects without NAFLD, while the prevalence of CKD was gradually increased as the IHTG content increased by quartiles (P for trend<0.001). After adjustment for multivariate metabolic factors, the risk of abnormal albuminuria and CKD was increased by 68% [OR (95% CI): 1.68 (1.21-2.33), P<0.01] and 54% [OR (95% CI): 1.54 (1.14-2.07), P<0.01] respectively per one standard deviation (SD) increase in IHTG content. The association between IHTG content and CKD was not changed by conventional risk factors, including age, BMI and hypertension (all P<0.05). CONCLUSION IHTG content is independently associated with CKD in obese adults.

Circulating neuregulin 4 levels are inversely associated with subclinical cardiovascular disease in obese adults.

Neuregulin 4 (Nrg4) has been identified as a new secreted adipokine that may protect against development of obesity and metabolic disorders. However, information is not available regarding the association between circulating Nrg4 and subclinical atherosclerosis in humans. We measured serum Nrg4 in 485 obese adult subjects (aged 40 years or older) who had the measurement of carotid intima-media thickness (CIMT) recruited from the community. Individuals with increased CIMT and carotid plaque had lower levels of circulating Nrg4 than controls (p < 0.05). The risks of increased CIMT and atherosclerotic plaque were significantly decreased by 28% and 31% [OR (95% CI): 0.72 (0.53–0.98) and 0.69 (0.50–0.96), respectively], adjusting for age, sex, current smoking, alcohol consumption, physical activity, BMI, systolic BP, fasting glucose, total cholesterol, HDL-c, HOMA-IR, and body fat. Importantly, individuals in the lowest quartile of serum Nrg4 were 3.70 times (p < 0.001) more likely to have increased CIMT and 2.06 times (p < 0.05) more likely to have atherosclerotic plaque than those in the highest quartile in multivariable logistic regression analyses. These findings suggest that circulating Nrg4 concentrations are inversely associated with subclinical atherosclerosis in obese adults, and indicating that circulating Nrg4 might play a role in identifying patients at high risk for CVD.

Attenuated associations between increasing BMI and unfavorable lipid profiles in Chinese Buddhist vegetarians

UNLABELLED Obesity is related to hyperlipidemia and risk of cardiovascular disease. Health benefits of vegetarian diets have well-documented in the Western countries where both obesity and hyperlipidemia were prevalent. We studied the association between BMI and various lipid/lipoprotein measures, as well as between BMI and predicted coronary heart disease probability in lean, low risk populations in Southern China. The study included 170 Buddhist monks (vegetarians) and 126 omnivore men. Interaction between BMI and vegetarian status was tested in the multivariable regression analysis adjusting for age, education, smoking, alcohol drinking, and physical activity. Compared with omnivores, vegetarians had significantly lower mean BMI, blood pressures, total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, total cholesterol to high density lipoprotein ratio, triglycerides, apolipoprotein B and A-I, as well as lower predicted probability of coronary heart disease. Higher BMI was associated with unfavorable lipid/lipoprotein profile and predicted probability of coronary heart disease in both vegetarians and omnivores. However, the associations were significantly diminished in Buddhist vegetarians. CONCLUSIONS Vegetarian diets not only lower BMI, but also attenuate the BMI-related increases of atherogenic lipid/ lipoprotein and the probability of coronary heart disease.

Ping-tang Recipe (平糖方) improves insulin resistance and attenuates hepatic steatosis in high-fat diet-induced obese rats

ObjectiveTo investigate the therapeutic effects of Ping-tang Recipe (平糖方, PTR) on high-fat diet (HFD)-induced insulin resistance and non-alcoholic fatty liver disease (NAFLD), and to elucidate the underlying mechanisms.MethodsForty male SD rats were included in the study. Ten rats were fed on normal diet as normal control, and thirty rats were fed on HFD for 8 weeks to induce obesity, followed with low dose (0.42 g/kg) or high dose (0.84 g/kg) of PTR or vehicle for 8 weeks with 10 animals for each group. Glucose metabolism and insulin sensitivity were evaluated by oral glucose tolerance test and insulin tolerance test. Hepatic steatosis was measured by immunohistochemistry. Liver lipid metabolic genes were analyzed by quantitative real-time polymerase chain reaction, while AMP-activated protein kinase (AMPK) expression was examined by Western blot.ResultsRats fed on HFD developed abdominal obesity, insulin resistance and NAFLD. PTR treatment reduced visceral fat (peri-epididymal and peri-renal) accumulation, improved glucose metabolism, and attenuated hepatic steatosis. The expressions of the key lipolytic regulating genes, including peroxisome proliferators-activated receptor γ co-activator 1α (PGC-1α), peroxisome proliferator-activated receptor γ (PRAR-γ) and α (PRAR-α), were up-regulated (P<0.05 or P<0.01), while the expressions of lipogenic genes such as sterol regulatory element-binding protein 1c (SREBP-1c), fatty acid synthase (FAS) and liver fatty acid-binding protein (L-FABP) were down-regulated (P<0.05 or P<0.01). In addition, PTR activated AMPK and promoted acetyl-CoA carboxylase phosphorylation in the liver.ConclusionsPTR improves insulin resistance and reverse hepatic steatosis in the rat model of HFD-induced obesity through promotion of lipolysis and reduction of lipogenesis, which involves the AMPK signaling pathway, thus representing a new therapeutic intervention for obesity related insulin resistance and NAFLD.