Levels of metabolic markers in drug-naive prediabetic and type 2 diabetic patients

High circulating fibroblast growth factor-21 levels as a screening marker in fatty pancreas patients

Background

The study aimed to detect the serum levels of fibroblast growth factor-21 (FGF-21) in fatty pancreas (FP) patients and to investigate their potential clinical value.

Methods

We screened patients with FP using transabdominal ultrasound. The anthropometric, biochemical and serum levels of FGF-21 were compared between the FP group and the normal control (NC) group. A receiver operating characteristic (ROC) curve was used to evaluate the predictive value of serum FGF-21 for FP patients.

Results

Compared with the NC group, body mass index, fasting blood glucose levels, uric acid levels and cholesterol levels of the FP group were significantly higher, while the high-density lipoprotein level was lower. In addition, levels of serum FGF-21, resistin, leptin and tumor necrosis factor-α were significantly higher than those in the NC group, while the serum adiponectin level was lower. Pearson analysis showed serum FGF-21 levels in FP patients were negatively correlated with leptin. The ROC curve showed the best critical value of the serum FGF-21 level in FP patients was 171 pg/mL (AUC 0.744, P = 0.002, 95% confidence intervals 0.636-0.852).

Conclusion

Serum FGF-21 was closely related to fatty pancreas. Detecting serum FGF-21 levels may help identify the population susceptible to FP.

Ameliorative Effect of Oxytocin on FBN1 and PEPCK Gene Expression, and Behavioral Patterns in Rats' Obesity-Induced Diabetes

Amelioration of hyperinsulinemia and insulin resistance associated with obesity is a cardinal target for therapeutics. Therefore, we investigated the relation of Fibrilln-1 (FBN1) mRNA expression and hepatic phosphoenolpyruvate caboxykinase (PEPCK) enzyme to the ameliorative impact of oxytocin on obesity-induced diabetes, suggesting glycogenolysis markers in diabetic models. Four groups of forty male Wistar rats were formed (n = 10): a control group fed basal diet and intraperitoneal injections of saline; an oxytocin-injected group; a diet-induced obese group fed a high-fat/high-sugar diet and injected with saline; a diet-induced obese group injected with oxytocin. Depending on blood glucose levels, obese groups were further sub-grouped into prediabetic, and diabetic rats, with 5 rats each, at the ninth and the 16th week of the feeding period, respectively. FBN1 expression and PEPCK activity were determined using the qPCR technique and some biochemical parameters (glycemic, lipid profile, kidney, and liver functions) were determined using kits. Obese groups showed an elevation of brain FBN1 expression, high serum lipid profile, high glucose level, and a deleterious impact on liver and kidney functions. Obese groups showed the stimulator effect of the PEPCK enzyme and time-dependent pathological changes in renal and hepatic tissues. The motor activities were negatively correlated with FBN1 gene expression in prediabetic and diabetic rats. In addition to our previous review of the crucial role of asprosin, here we showed that oxytocin could ameliorate obesity-induced diabetes and decrease FBN1 gene expression centrally to block appetite. Oxytocin caused decreases in PEPCK enzyme activity as well as glycogenolysis in the liver. Therefore, oxytocin has a potential effect on FBN1 expression and PEPCK enzyme activity in the obesity-induced diabetic-rat model.

Serum nesfatin-1 is a biomarker of pre-diabetes and interplays with cardiovascular risk factors

Background and objectives

Nesfatin-1 as a potent anorexigenic peptide is secreted by pancreatic β cells. Conflicting data are available about its level among diabetic patients. Our study aimed to assess nesfatin-1 levels in newly diagnosed drug-naïve diabetic and pre-diabetic patients and its association with cardio-metabolic risk and insulin resistance (IR). This case-control study included drug-naive patients with DMT2 (group 1, n = 30) and pre-diabetes (group 2, n = 30) in addition to healthy subjects (group 3, n = 28). Anthropometric and routine biochemical assessments were performed. Serum nesfatin-1and plasma insulin levels were assessed by ELISA methods. Homeostatic model for assessment of IR (HOMA-IR) was calculated.

Results

Serum nesfatin-1 was significantly lower in diabetic and pre-diabetic compared to healthy subjects (3.89 ± 1.1 ng/dl and 7.47 ± 1.22 ng/dl versus 15.39 ± 3.53 respectively, p < 0.001). Also diabetic patients had statistically significant lower nesfatin-1 levels than pre-diabetic patients (p < 0.001) Roc curve analysis identified cut-off values of ≤ 9 ng/dl and ≤ 5.5 ng/dl with an AUC of 0.94 and 0.97, sensitivity of 96.7 and 100%, and specificity of 93.3% and 96.7% for diagnosis of pre-diabetes and diabetes respectively. Using bivariate analysis, nesfatin-1 was negatively correlated with glycemic parameters (fasting and 2 h postprandial blood sugar, HBA1c), IR parameters (fasting insulin and HOMA-IR) and atherogenic lipid profile (triglyceride, cholesterol, and LDL-c); and positively correlated to HDL-c in both diabetic and pre-diabetic but not in healthy.

Conclusion

Nesfatin-1 is an excellent predictor for pre-diabetes and DMT2. It is associated with favorable glucose and lipid metabolism probably via insulin signaling pathway.

The Variation and Correlation of Serum Adiponectin, Nesfatin-1, IL-6, and TNF-α Levels in Prediabetes

BACKGROUND

The variation and correlation among adiponectin, nesfatin-1, tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6), which may be involved in the development of the decline of health into prediabetes and diabetes, have not been elucidated. This study aims to investigate the roles of these cytokines in this process.

METHODS

Seventy-two type 2 diabetes mellitus (T2DM) patients, 75 prediabetics, and 72 healthy individuals were enrolled in our case control study. Serum adiponectin, nesfatin-1, TNF-α, and IL-6 were tested with appropriate kits, and primary data were analyzed with correct methods.

RESULTS

Serum levels of each cytokine in patients with prediabetes were between T2DM and the healthy, and significant differences were found among them. TNF-α and nesfatin-1 levels in T2DM were obviously different compared to prediabetes or the healthy; IL-6 and adiponectin levels in the healthy group were significantly changed in contrast to prediabetes or T2DM. Correlation analysis found that in prediabetics, adiponectin was positively correlated with TNF-α (R = 0.2939, P = 0.0105) and IL-6 (R = 0.3918, P = 0.0005), and their relationship was greatly strengthened in prediabetes accompanied by insulin resistance (TNF-α: R = 0.7732, P < 0.0001, IL-6: R = 0.6663, P = 0.0005). We also demonstrated that declined adiponectin (OR = 6.238, P = 0.019) and nesfatin-1 (OR = 2.812, P = 0.01) and elevated TNF-α (OR = 5.541, P = 0.001) were risk factors for prediabetes toward diabetes.

CONCLUSIONS

This research proved significant variations of adiponectin, nesfatin-1, IL-6, and TNF-α levels in the healthy, prediabetics, and T2DM, suggesting a slow and gradual change during the progression from a healthy condition toward diabetes via prediabetes.

[Myokines and adipomyokines: inflammatory mediators or unique molecules of targeted therapy for obesity?]

Skeletal muscles make up about 25% of the total mass in children and more than 40% in adults. Studies of the last twenty years have shown that along with the main functions, muscle tissue has hormonal activity. It was found that myocytes are able to release signaling molecules-myokines. They act auto-and paracrine within the muscle, and at a high level-through the systemic circulation, carrying out interactions between skeletal muscles and various organs and tissues, such as the liver, bone and adipose tissue, the brain. It is proved that the key factor in the expression of myokines is physical activity, and their level largely depends on physical fitness, the amount of skeletal muscle mass and its composition (the ratio of fast and slow fibers), on the intensity and duration of physical activity. Myokines have a wide range of physiological effects: myostatin suppresses the growth and differentiation of muscle tissue, and decorin, acting as its antagonist, promotes muscle hypertrophy. Interleukin 6 provides an energy substrate for contracting muscle fibers, fibroblast growth factor 21 activates the mechanisms of energy production during fasting and improves tissue sensitivity to insulin; irisin stimulates thermogenesis, glucose uptake by myocytes, and also contributes to an increase in bone mineral density. The study of myokines is one of the key links in understanding the mechanisms underlying obesity and metabolic complications, the consequences of a sedentary lifestyle, as well as the implementation of the action of physical activity. Taking into account the physiological effects of myokines in the body, in the future they can become therapeutic targets for the treatment of these conditions.

Irisin and Autophagy: First Update

Aging and sedentary life style are considered independent risk factors for many disorders. Under these conditions, accumulation of dysfunctional and damaged cellular proteins and organelles occurs, resulting in a cellular degeneration and cell death. Autophagy is a conserved recycling pathway responsible for the degradation, then turnover of cellular proteins and organelles. This process is a part of the molecular underpinnings by which exercise promotes healthy aging and mitigate age-related pathologies. Irisin is a myokine released during physical activity and acts as a link between muscles and other tissues and organs. Its main beneficial function is the change of subcutaneous and visceral adipose tissue into brown adipose tissue, with a consequential increase in thermogenesis. Irisin modulates metabolic processes, acting on glucose homeostasis, reduces systemic inflammation, maintains the balance between resorption and bone formation, and regulates the functioning of the nervous system. Recently, some of its pleiotropic and favorable properties have been attributed to autophagy induction, posing irisin as an important regulator of autophagy by exercise. This review article proposes to bring together for the first time the "state of the art" knowledge regarding the effects of irisin and autophagy. Furthermore, treatments on relation between exercise/myokines and autophagy have been also achieved.

Hepsin enhances liver metabolism and inhibits adipocyte browning in mice

Hepsin is a transmembrane serine protease primarily expressed in the liver. To date, the physiological function of hepsin remains poorly defined. Here we report that hepsin-deficient mice have low levels of blood glucose and lipids and liver glycogen, but increased adipose tissue browning and basal metabolic rates. The phenotype is caused by reduced hepatocyte growth factor activation and impaired Met signaling, resulting in decreased liver glucose and lipid metabolism and enhanced adipocyte browning. Hepsin-deficient mice exhibit marked resistance to high-fat diet-induced obesity, hyperglycemia, and hyperlipidemia. In db/db mice, hepsin deficiency ameliorates obesity and diabetes. These data indicate that hepsin is a key regulator in liver metabolism and energy homeostasis, suggesting that hepsin could be a therapeutic target for treating obesity and diabetes.

Several Circulating Biomarkers for PCOS Diagnosis

AIMS

Irisin, Betatrophin and Zinc-α2-glycoprotein (ZAG) have been shown to be associated with insulin resistance (IR) and polycystic ovary syndrome (PCOS), respectively. The purpose of this study is to explore the potential accuracy of this combination of three cytokines in screening PCOS.

METHODS

186 individuals were recruited for this study. Circulating Irisin, Betatrophin and ZAG concentrations were measured by enzyme-linked immunosorbent assay. The association between these serum biomarkers and PCOS was assessed by logistic regression analysis. Receiver operating curve (ROC) analysis was performed to evaluate the diagnostic value of these biomarkers for PCOS women.

RESULTS

In women with PCOS, serum Irisin and Betatrophin levels were markedly elevated compared to those in healthy controls (p<0.01), while ZAG levels were lower (p<0.01). PCOS women with IR (M-value<6.28) had lower circulating ZAG concentrations, and higher circulating Irisin and Betatrophin levels relative to PCOS women without IR (M-value ≥ 6.28). ROC curve analyses showed that the AUC for Irisin, ZAG and Betatrophin for predicting PCOS were 0.77, 0.83 and 0.85, respectively. In a joint ROC curves analysis of these serum markers and other parameters, the results showed that the AUC was 0.93, and the sensitivity and specificity were 82.1 % and 92.3 %, respectively.

CONCLUSIONS

When compared to using single cytokine, the analysis of Irisin, ZAG and Betatrophin elevates the accuracy in diagnosing PCOS.

The Adipokine Network in Rheumatic Joint Diseases

Rheumatic diseases encompass a diverse group of chronic disorders that commonly affect musculoskeletal structures. Osteoarthritis (OA) and rheumatoid arthritis (RA) are the two most common, leading to considerable functional limitations and irreversible disability when patients are unsuccessfully treated. Although the specific causes of many rheumatic conditions remain unknown, it is generally accepted that immune mechanisms and/or uncontrolled inflammatory responses are involved in their etiology and symptomatology. In this regard, the bidirectional communication between neuroendocrine and immune system has been demonstrated to provide a homeostatic network that is involved in several pathological conditions. Adipokines represent a wide variety of bioactive, immune and inflammatory mediators mainly released by adipocytes that act as signal molecules in the neuroendocrine-immune interactions. Adipokines can also be synthesized by synoviocytes, osteoclasts, osteoblasts, chondrocytes and inflammatory cells in the joint microenvironment, showing potent modulatory properties on different effector cells in OA and RA pathogenesis. Effects of adiponectin, leptin, resistin and visfatin on local and systemic inflammation are broadly described. However, more recently, other adipokines, such as progranulin, chemerin, lipocalin-2, vaspin, omentin-1 and nesfatin, have been recognized to display immunomodulatory actions in rheumatic diseases. This review highlights the latest relevant findings on the role of the adipokine network in the pathophysiology of OA and RA.

Effect of insulin-glucose metabolism compared with obesity on adipose omentin gene expression in different models of diabetic C57BL/6 mice

BACKGROUND

Omentin, releasing by adipose-tissue may be related to glucose metabolism. The omentin circulating levels and the related mRNA expression in visceral adipose-tissue are different in types of diabetes and the exact function of this molecule is still unknown. The aim of this study was to examine omentin gene expression in adipose-tissues of type-1 and type-2 diabetic mice for the investigation of the effects of fat-mass and insulin-glucose metabolism.

METHODS

In this study, 36 C57BL/6 mice were divided into four experimental groups, including control, type-1 diabetes (inducted by streptozotocin), type-2 diabetes with obesity (high-fat diet + low-dose-streptozotocin [HFD + STZ]), and type-2 with normal weight (normal-pellet diet + low-dose-streptozotocin [NPD + STZ]). The present study involved the measurements of oral-glucose-tolerance-test and the levels of biochemical parameters, including blood glucose, omentin, insulin, lipid-profile, as well as aminotransferases. In addition, the omentin mRNA expression was evaluated by real-time polymerase-chain-reaction.

RESULTS

The results of omentin gene expression analysis showed a significant difference between mRNA expressions in the experimental groups. The plasma omentin levels were significantly higher in type-1 diabetes group and lower in type-2 diabetes with NPD + STZ; however, the plasma omentin levels were not changed in the HFD + STZ group. In addition, the findings of serum-biochemical analysis revealed significant differences, compared to the control-group.

CONCLUSIONS

The omentin expression may be affected by insulin and glucose levels in different types of diabetes more than fat-mass, and due to the local activity, the serum omentin may not comply with its gene expression.

Fibroblast growth factor 21 in lipid metabolism and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in several developed countries, ranging from simple non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH) and cirrhosis. Currently, NAFLD has been confirmed to be associated with dyslipidemia, insulin resistance, and pre-diabetes, which are always grouped together as metabolic syndrome. Fibroblast growth factor 21 (FGF21) plays an important role in liver pathophysiology with multiple metabolic functions. Accumulating evidence has shown that FGF21 could directly modulate lipid metabolism and reduce lipid accumulation in hepatocytes through an insulin-independent pathway, thus suppressing the pathogenesis of NAFLD. Furthermore, treatment with FGF21 could obviously reverse NAFLD and synergistically alleviate obesity and counteract insulin resistance. In this review, we summarize the current knowledge of FGF21 and the evidence of FGF21 as an important regulator in hepatic lipid metabolism. The mechanisms by which FGF21 affects the pathogenesis of NAFLD would also be proposed for the further understanding of FGF21.

Increased serum/plasma fibroblast growth factor 21 in type 2 diabetes mellitus: a systematic review and meta-analysis

OBJECTIVES

Fibroblast growth factor-21 (FGF-21) plays an important role in glucose and lipid metabolism. This study aims to systemically review the evidence regarding the relationship between the FGF-21 levels and type 2 diabetes mellitus (T2DM), as well as the related influential factors.

METHODS

Research related to plasma/serum FGF-21 levels in patients with T2DM and healthy controls were searched in PubMed, EMBASE and The Cochrane Library databases (up to 31 March 2017). Pooled standard mean difference (SMD) with 95% CI was calculated by fixed-effect or random-effect model analysis. Heterogeneity test was performed by the Q-statistic and quantified using I 2, and publication bias was evaluated using a funnel plot and Egger's linear regression test.

RESULTS

In total, 317 articles were obtained after searching databases, and 11 studies with 866 patients with T2DM and 629 controls were finally included. Meta-analysis revealed that, compared with the control group, the T2DM group had a significantly higher plasma/serum FGF-21 level (p < 0.001), with the SMD of 1.34% and 95% CI (0.70 to 1.98). Meta-regression analysis and subgroup analyses suggested that body mass index (BMI), triglycerides (TG) and total cholesterol (TC) were likely related to the observed FGF-21 differences between two groups.

CONCLUSIONS

Overall, our study suggests that patients with T2DM have significantly higher plasma/serum FGF-21 levels, and the FGF-21 levels were influenced by BMI, TC and TG.

Fasting plasma glucose is a stronger predictor of diabetes than triglyceride-glucose index, triglycerides/high-density lipoprotein cholesterol, and homeostasis model assessment of insulin resistance: Tehran Lipid and Glucose Study

AIMS

To compare the impact of triglyceride-glucose index (TyG-index), the product of fasting plasma glucose (FPG) and triglycerides (TG) with FPG, 2 h post-challenge plasma glucose (2 h-PCPG), TG/high-density lipoprotein cholesterol (TG/HDL-C), and homeostasis model assessment of insulin resistance (HOMA-IR) indices for prediction of type 2 diabetes (T2D) in Iranian adults during a median follow-up of 12 years.

METHODS

Study population included 4419 (1858 men) subjects with mean age of 40.6 ± 13.2 years. Multivariable Cox proportional hazard models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for each 1-standard deviation increase in each predictor. Areas under the receiver operating characteristics curves (AUC) and 95% CIs were calculated.

RESULTS

During follow-up, 215 men and 288 women developed T2D. The multivariable HRs for FPG, 2 h-PCPG, TyG-index, HOMA-IR, HOMA2-IR, and TG/HDL-C were 2.20, 1.97, 1.71, 1.33, 1.30, and 1.35 in men and 2.13, 2.11, 1.44, 1.37, 1.32, and 1.36 in women (all P < 0.001). Among the total population, the AUC for FPG [0.752 (0.727-0.776)] was similar to 2 h-PCPG but higher than TyG-index [0.697 (0.673-0.720)], TG/HDL-C [0.644 (0.620-0.669)], HOMA-IR [0.684 (0.659-0.710)], and HOMA2-IR [0.656 (0.630-0.682)]. In men, AUC of TyG-index was higher than TG/HDL-C but did not differ with HOMA-IR indices. In women, the AUC of TyG-index was higher than HOMA2-IR and TG/HDL-C, but was similar to that of HOMA-IR.

CONCLUSIONS

FPG is a stronger predictor of T2D than the TyG-index, TG/HDL-C, and HOMA-IR indices. Although TyG-index was better than TG/HDL-C in both genders, it did not rank above HOMA-IR.

Cross-sectional correlates of nesfatin and lipopolysaccharide binding protein in metabolic syndrome patients with and without prediabetes

Background Metabolic syndrome (MetS) and prediabetes (preDM) have crosslinked pathophysiologies with central obesity and insulin resistance (IR). This study aimed to compare and correlate nesfatin and lipopolysaccharide binding protein (LBP) plasma levels, adiposity, atherogenicity and hematological indices between non-diabetic MetS, newly diagnosed drug naive pre-diabetic MetS patients vs. normoglycemic lean controls. Materials and methods In a cross-sectional study, 29 apparently healthy controls, 29 non-diabetic MetS subjects and 30 preDM-MetS patients were recruited. Results The LBP level (ng/mL) was substantially higher in both MetS (non- and pre-diabetic) groups compared to healthy controls. In contrast, circulating level of nesfatin (pg/mL) was lower, though not significantly; in both pre-diabetic and non-diabetic MetS patients compared to lean normoglycemic controls. No correlation was found between nesfatin and LBP in MetS pool (n = 59). Remarkably unlike blood indices; adiposity indices [body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height (WHtR) ratio, hip circumference (HC), body adiposity index (BAI), visceral adiposity index (VAI), lipid accumulation product (LAP) but not conicity index (CI)], atherogenicity indices [(atherogenicity index of plasma (AIP = Log10(TG/HDL-C ratio)), low density lipoprotein cholesterol to high density lipoprotein cholesterol ratio (LDL-C/HDL-C) and non-high density lipoprotein cholesterol (non-HDL-C)] were substantially higher in both MetS (non- and pre-diabetic) groups vs. those of controls. Exceptionally pronounced and proportional nesfatin-DBP and LBP-BAI correlations were identified in total MetS pool (both non-diabetic and pre-diabetic). Conclusions Nesfatin and LBP can be potential targets and surrogate biomarkers to use as putative prognostic/predictive tools for the prevention and treatment for MetS and related disorders.

Variable oxytocin levels in humans with different degrees of obesity and impact of gastric bypass surgery

Exogenous oxytocin administration in obese mice, rats, and monkeys was shown to induce sustained weight loss, mostly due to a decrease in fat mass, accompanied by an improvement of glucose metabolism. A pilot study in obese humans confirmed the weight-reducing effect of oxytocin. Knowledge about circulating oxytocin levels in human obesity might help indicating which obese subjects could potentially benefit from an oxytocin treatment. Conclusive results on this topic are missing. The aim of this study was to measure circulating oxytocin levels in lean (n = 37) and obese (n = 72) individuals across a wide range of body mass index (BMI) values (18.5-60 kg/m²) and to determine the impact of pronounced body weight loss following gastric bypass surgery in 12 morbidly obese patients. We observed that oxytocin levels were unchanged in overweight and in class I and II obese subjects and only morbidly obese patients (obesity class III, BMI > 40 kg/m²) exhibited significantly higher levels than lean individuals, with no modification 1 year after gastric bypass surgery, despite substantial body weight loss. In conclusion, morbidly obese subjects present elevated oxytocin levels which were unaltered following pronounced weight loss.

Irisin in metabolic diseases

INTRODUCTION

Irisin is a myokine/adipokine induced by the exercise in mice and humans, which is proposed to induce "browning" of white adipose tissue, its primary target, thus increasing thermogenesis and energy expenditure. Since its identification, irisin has been linked to favorable effects on metabolic diseases, including obesity, type 2 diabetes mellitus (T2DM), lipid metabolism and cardiovascular disease (CVD), nonalcoholic fatty liver disease (NAFLD), polycystic ovary syndrome (PCOS), and metabolic bone diseases. Generally, despite the promising profile of irisin in rodents, its effects on human are less recognized.

REVIEW

Most, but not all studies show a positive association between irisin and indices of adiposity. In T2DM, NAFLD, and CVD, most observational studies reported lower irisin levels in patients than controls. Regarding metabolic bone diseases, irisin is positively associated with bone mineral density and strength in athletes, and inversely associated with osteoporotic fractures in postmenopausal osteoporosis. In PCOS, data remain largely conflicting. Irisin does not seem to be further reduced when two metabolic diseases, e.g., T2DM and NAFLD, or obesity and NAFLD exist though more data are needed. Furthermore, it seems that diverse confounders may have affected the results of different clinical studies.

CONCLUSION

Irisin remains an appealing molecule from a pathophysiological point of view and an appealing therapeutic target for metabolic diseases, albeit much research is still needed.

Classical (adiponectin, leptin, resistin) and new (chemerin, vaspin, omentin) adipocytokines in patients with prediabetes

Background

In the last decade, there has been an increased interest toward fat tissue as an endocrine organ that secretes many cytokines and bioactive mediators that play a role in insulin sensitivity, inflammation, coagulation and the pathogenesis of atherosclerosis. The aim of this study was to investigate classical (adiponectin, leptin, resistin) and new (chemerin, vaspin, omentin) adipocytokine levels in subjects with prediabetes [impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT)] and obese subjects with normoglycemia.

Methods

In this study, 80 patients with a mean age of 50.4 ± 10.6 years were recruited, divided into two groups with similar age and body mass index (BMI) – with obesity and normoglycemia (n = 41) and with obesity and prediabetes (n = 39).

Results

Serum adiponectin levels were significantly higher in subjects with normoglycemia compared to patients with prediabetes. Adiponectin has a good discriminating power to distinguish between patients with and without insulin resistance in our study population [area under the curve (AUC) = 0.728, p = 0.002]. Other adipocytokine levels were not significantly different between the two groups. The patients with metabolic syndrome (MetS) had significantly lower levels of leptin compared to those without MetS (33.03 ± 14.94 vs. 40.24 ± 12.23 ng/mL) and this difference persisted after adjustment for weight and BMI. Receiver operating characteristic (ROC) analysis showed that low serum leptin can predict the presence of MetS (p = 0.03), AUC = 0.645.

Conclusion

Serum adiponectin is statistically higher in patients with normoglycemia compared to those with prediabetes and has a predictive value for distinguishing between patients with and without insulin resistance in the studied population. Serum leptin has a good predictive value for distinguishing between patients with and without MetS in the studied population.

Angiopoietin-like protein 8: An attractive biomarker for the evaluation of subjects with insulin resistance and related disorders

Insulin resistance is prevalent worldwide and is associated with many metabolic diseases, in particular, type 2 diabetes mellitus (T2DM), obesity, nonalcoholic fatty liver disease (NAFLD), polycystic ovary syndrome (PCOS) and metabolic syndrome (MetS). Angiopoietin-like protein 8 (ANGPTL8), a newly-identified secreted protein composing of 198 amino acids, is enriched in the liver of human. Considering its promising potential for β-cell proliferation and therapeutic prospect for diabetes, ANGPTL8 has aroused extensive interests. However, a recent collaborative study confirmed that ANGPTL8 didn't stimulate dramatic β-cell regeneration. At present, a controversial scientific discussion on whether and how ANGPTL8 regulate insulin resistance has been ongoing. Interestingly, several in vitro and in vivo studies have suggested the complex roles of ANGPTL8 in insulin resistance. Data resulting from cross-sectional and longitudinal researches in human individuals involving the influence of ANGPTL8 on the development of insulin resistance were controversial. We therefore summarize currently clinical literature to exploit whether this exciting hormone could be applied for clinical application asa potential clinical biomarker to predict insulin resistance and related disorders.

Role of Omentin, Vaspin, Cardiotrophin-1, TWEAK and NOV/CCN3 in Obesity and Diabetes Development

Adipose tissue releases bioactive mediators called adipokines. This review focuses on the effects of omentin, vaspin, cardiotrophin-1, Tumor necrosis factor-like Weak Inducer of Apoptosis (TWEAK) and nephroblastoma overexpressed (NOV/CCN3) on obesity and diabetes. Omentin is produced by the stromal-vascular fraction of visceral adipose tissue. Obesity reduces omentin serum concentrations and adipose tissue secretion in adults and adolescents. This adipokine regulates insulin sensitivity, but its clinical relevance has to be confirmed. Vaspin is produced by visceral and subcutaneous adipose tissues. Vaspin levels are higher in obese subjects, as well as in subjects showing insulin resistance or type 2 diabetes. Cardiotrophin-1 is an adipokine with a similar structure as cytokines from interleukin-6 family. There is some controversy regarding the regulation of cardiotrophin-1 levels in obese -subjects, but gene expression levels of cardiotrophin-1 are down-regulated in white adipose tissue from diet-induced obese mice. It also shows anti-obesity and hypoglycemic properties. TWEAK is a potential regulator of the low-grade chronic inflammation characteristic of obesity. TWEAK levels seem not to be directly related to adiposity, and metabolic factors play a critical role in its regulation. Finally, a strong correlation has been found between plasma NOV/CCN3 concentration and fat mass. This adipokine improves insulin actions.

Circulating Nesfatin-1 Levels and Type 2 Diabetes: A Systematic Review and Meta-Analysis

The role of nesfatin-1 in glucose homeostasis has been investigated previously. However, although numerous studies have examined the relationships between circulating nesfatin-1 levels and type 2 diabetes, the conclusions are contradictory. We aimed to probe the relationship between circulating nesfatin-1 levels and type 2 diabetes by meta-analysis. Seven studies including 328 type 2 diabetes patients and 294 control subjects were included. Although there was no obvious difference in circulating nesfatin-1 levels between patients with type 2 diabetes and the control group (MD = -0.04; 95% CI = -0.32 to -0.23), subgroup analysis showed higher nesfatin-1 levels in newly diagnosed type 2 diabetes patients (MD = 0.59; 95% CI = 0.45 to 0.74) and significantly lower nesfatin-1 levels in type 2 diabetes patients receiving antidiabetic treatment (MD = -0.26; 95% CI = -0.33 to -0.20). In conclusion, the analysis supports a relationship between circulating nesfatin-1 levels and type 2 diabetes, where newly diagnosed type 2 diabetes was associated with an elevated Nesfatin-1 level, and type 2 diabetes patients receiving antidiabetic treatment showed lower circulating nesfatin-1 levels.

Serum Concentrations of Betatrophin and Its Association with Indirect Indices of Insulin Resistance and Beta Cell Function in Women with Polycystic Ovary Syndrome

INTRODUCTION

Data underline the role of betatrophin in glucose homeostasis. Polycystic ovary syndrome (PCOS) is characterized by insulin resistance (IR). The aim of our study was to investigate the relationship of serum betatrophin concentrations with indirect indices of IR and insulin secretion in women with PCOS, compared to the control group.

METHODS

The study group comprised 43 women with PCOS and 16 controls. IR was assessed by HOMA-IR and Matsuda index. Insulin secretion was evaluated with HOMA-B. An oral glucose tolerance test (OGTT) with estimation of serum betatrophin concentrations was performed.

RESULTS

Glucose load resulted in an increase in serum betatrophin concentrations in the control group (p = 0.02). Serum betatrophin concentrations at 120 min of OGTT were lower in women with PCOS than in the control group (p = 0.02). We observed positive correlations between baseline serum betatrophin concentrations and HOMA-IR (r = 0.39, p = 0.008), negative correlations with Matsuda index (r = -0.31, p = 0.004), and a positive relationship with HOMA-B (r = 0.38, p = 0.01) in women with PCOS. Multiple regression analysis revealed that HOMA-B (β = 0.47, p = 0.001) was an independent factor connected to serum betatrophin levels in PCOS.

CONCLUSIONS

Serum concentrations of betatrophin are connected with insulin resistance and beta cell function and did not change after glucose load in women with PCOS.