Higher vaspin levels in subjects with obesity and type 2 diabetes mellitus: a meta-analysis

The role of adipose tissue in cardiovascular health and disease

Accumulating knowledge on the biology and function of the adipose tissue has led to a major shift in our understanding of its role in health and disease. The adipose tissue is now recognized as a crucial regulator of cardiovascular health, mediated by the secretion of several bioactive products, including adipocytokines, microvesicles and gaseous messengers, with a wide range of endocrine and paracrine effects on the cardiovascular system. The adipose tissue function and secretome are tightly controlled by complex homeostatic mechanisms and local cell-cell interactions, which can become dysregulated in obesity. Systemic or local inflammation and insulin resistance lead to a shift in the adipose tissue secretome from anti-inflammatory and anti-atherogenic towards a pro-inflammatory and pro-atherogenic profile. Moreover, the interplay between the adipose tissue and the cardiovascular system is bidirectional, with vascular-derived and heart-derived signals directly affecting adipose tissue biology. In this Review, we summarize the current knowledge of the biology and regional variability of adipose tissue in humans, deciphering the complex molecular mechanisms controlling the crosstalk between the adipose tissue and the cardiovascular system, and their possible clinical translation. In addition, we highlight the latest developments in adipose tissue imaging for cardiovascular risk stratification and discuss how therapeutic targeting of the adipose tissue can improve prevention and treatment of cardiovascular disease.

Associations Between Vaspin Rs2236242 Gene Polymorphism, Walking Time and the Risk of Metabolic Syndrome

The associations between serum vaspin levels and metabolic or coronary artery disease (CAD) and polycystic ovary syndrome (PCOS) is under the scope of current researchers. Therefore, this adipokine can be considered as a biomarker of metabolic syndrome (MetS). The aim of the study was to analyze the associations between the vaspin rs2236242 polymorphism and physical activity in relation to MetS and its components. The analysis involved the genetic material and clinical data of 108 individuals with MetS and 110 controls. Vaspin rs2236242 polymorphism was detected using the tetra-primer amplification-refractory mutation system polymerase chain reaction (T-ARMS PCR) method. The TA genotype of vaspin rs2236242 was associated with a greater risk of MetS and its components compared with the TT genotype. The analysis of interactions between genotype and walking time revealed that a walking time longer than 60 min./day significantly decreased the risk of MetS in the TA carriers (p = 0.007). The obtained results suggest that any unfavorable effect of the TA genotype of the vaspin rs2236242 polymorphism can be essentially reduced, or even reversed, in a case of individuals walking longer than 60 min. a day. The analysis of the interaction between vaspin rs2236242 polymorphism and walking showed that a walking time of longer than 1 hour a day significantly reduced the risk of MetS, elevated blood pressure and triglycerides concentration.

Adipose Tissue-Derived Signatures for Obesity and Type 2 Diabetes: Adipokines, Batokines and MicroRNAs

: Obesity is one of the main risk factors for type 2 diabetes mellitus (T2DM). It is closely related to metabolic disturbances in the adipose tissue that primarily functions as a fat reservoir. For this reason, adipose tissue is considered as the primary site for initiation and aggravation of obesity and T2DM. As a key endocrine organ, the adipose tissue communicates with other organs, such as the brain, liver, muscle, and pancreas, for the maintenance of energy homeostasis. Two different types of adipose tissues-the white adipose tissue (WAT) and brown adipose tissue (BAT)-secrete bioactive peptides and proteins, known as "adipokines" and "batokines," respectively. Some of them have beneficial anti-inflammatory effects, while others have harmful inflammatory effects. Recently, "exosomal microRNAs (miRNAs)" were identified as novel adipokines, as adipose tissue-derived exosomal miRNAs can affect other organs. In the present review, we discuss the role of adipose-derived secretory factors-adipokines, batokines, and exosomal miRNA-in obesity and T2DM. It will provide new insights into the pathophysiological mechanisms involved in disturbances of adipose-derived factors and will support the development of adipose-derived factors as potential therapeutic targets for obesity and T2DM.

Treatment with direct-acting antivirals improves peripheral insulin sensitivity in non-diabetic, lean chronic hepatitis C patients

BACKGROUND AND AIMS

Hepatitis C virus (HCV) infection is associated with insulin resistance, which may lead to type 2 diabetes and its complications. Although HCV infects mainly hepatocytes, it may impair insulin sensitivity at the level of uninfected extrahepatic tissues (muscles and adipose tissue). The aim of this study was to assess whether an interferon-free, antiviral therapy may improve HCV-associated hepatic vs. peripheral insulin sensitivity.

METHODS

In a single-arm exploratory trial, 17 non-diabetic, lean chronic hepatitis C patients without significant fibrosis were enrolled, and 12 completed the study. Patients were treated with a combination of sofosbuvir/ledipasvir and ribavirin for 12 weeks, and were submitted to a 2-step euglycemic hyperinsulinemic clamp with tracers, together with indirect calorimetry measurement, to measure insulin sensitivity before and after 6 weeks of antivirals. A panel of 27 metabolically active cytokines was analyzed at baseline and after therapy-induced viral suppression.

RESULTS

Clamp analysis performed in 12 patients who achieved complete viral suppression after 6 weeks of therapy showed a significant improvement of the peripheral insulin sensitivity (13.1% [4.6-36.7], p = 0.003), whereas no difference was observed neither in the endogenous glucose production, in lipolysis suppression nor in substrate oxidation. A distinct subset of hepatokines, potentially involved in liver-to-periphery crosstalk, was modified by the antiviral therapy.

CONCLUSION

Pharmacological inhibition of HCV improves peripheral (but not hepatic) insulin sensitivity in non-diabetic, lean individuals with chronic hepatitis C without significant fibrosis.

Yogurt improves insulin resistance and liver fat in obese women with nonalcoholic fatty liver disease and metabolic syndrome: a randomized controlled trial

BACKGROUND

Because consumption of conventional yogurt has beneficial effects in a healthy population, and insulin resistance (IR) is the mutual pathogenesis in nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS), we hypothesized that yogurt would ameliorate IR in patients with NAFLD and MetS.

OBJECTIVES

The aim of this study was to investigate the effects of yogurt on IR and secondary endpoints including liver fat, gut microbiota, and serum biomarkers of inflammation and oxidative stress in obese women with NAFLD and MetS.

METHODS

One hundred obese women aged 36-66 y with both NAFLD and MetS were randomly assigned to consume 220 g/d of either conventional yogurt or milk for 24 wk. At baseline and week 24, we measured anthropometric indices, serum glucose, insulin, lipids, and cytokines in all participants, and liver fat and gut microbiota in 20 participants randomly selected from each group.

RESULTS

Forty-eight participants from the yogurt group and 44 from the milk group completed the intervention. Compared with milk, yogurt significantly decreased the homeostasis model assessment of insulin resistance (-0.53; 95% CI: -1.03, -0.02), fasting insulin (-2.77 mU/L; 95% CI: -4.91, -0.63 mU/L), 2-h insulin (-25.5 mU/L; 95% CI: -33.0, -17.9 mU/L), 2-h area under the curve for insulin (-29.4 mU/L · h; 95% CI: -44.0, -14.8 mU/L · h), alanine aminotransferase (-4.65 U/L; 95% CI: -8.67, -0.64 U/L), intrahepatic lipid (-3.44%; 95% CI: -6.19%, -0.68%), and hepatic fat fraction (-3.48%; 95% CI: -6.34%, -0.63%). Yogurt also decreased serum LPS (-0.31 EU/mL; 95% CI: -0.48, -0.14 EU/mL), fibroblast growth factor 21 (-57.76 pg/mL; 95% CI: -86.32, -29.19 pg/mL), lipids, and biomarkers of inflammation and oxidative stress, and altered gut microbiota composition. Mediation analysis showed that yogurt may improve IR by reducing serum lipids, inflammation, oxidative stress, and LPS.

CONCLUSIONS

Yogurt was better than milk at ameliorating IR and liver fat in obese Chinese women with NAFLD and MetS, possibly by improving lipid metabolism, reducing inflammation, oxidative stress, and LPS, and changing the gut microbiota composition. This trial was registered at www.chictr.org.cn as ChiCTR-IPR-15006801.

Hyperlipidemias and Obesity

The organs require oxygen and other types of nutrients (amino acids, sugars, and lipids) to function, the heart consuming large amounts of fatty acids for oxidation and adenosine triphosphate (ATP) generation.

Chemerin rs17173608 and vaspin rs2236242 gene variants on the risk of end stage renal disease (ESRD) and correlation with plasma malondialdehyde (MDA) level

Introduction: End-stage renal disease (ESRD) is associated with critical kidney illness that seriously affects the lifespan. Genetic factors and oxidative stress could play critical role in the development of ESRD. We assessed the association between chemerin rs17173608 T/G and vaspin rs2236242 T/A genes variants with the risk of ESRD and their correlation with plasma malondialdehyde (MDA) level.

Materials and methods: In a case-control study, 131 gender and age-matched unrelated healthy controls and 110 ESRD patients were enrolled. The chemerin rs17173608 T/G and vaspin rs2236242 T/A were detected by Tetra primer-amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR). The MDA concentration was determined by HPLC.

Results: Our findings for the first time revealed that in codominant genetic model (T/G vs. T/T genotype), the T/G genotype of chemerin gene significantly had a protective role against ESRD susceptibility. Also, in the presence of chemerin G allele, the risk of ESRD decreased by 0.79-fold (p = .048) in Kurdish population of Iran. The MDA serum levels in ESRD patients carrying the chemerin T/G + G/G genotype of rs17173608 T/G and also in carriers of A/A + T/A genotype of vaspin rs2236242 T/A were significantly higher compared to those in control subjects. The overall distribution of vaspin rs2236242 T/A genotypes and alleles comparing ESRD patients and healthy subjects were not statistically significant.

Conclusion: We found that the G allele of chemerin rs17173608 compared to T allele decreased the risk of ESRD, and there was a significant association between chemerin and vaspin variants with plasma MDA level in a sample of the Iranian population.

Effects of Vaspin on Insulin Resistance in Rats and Underlying Mechanisms

Insulin resistance (IR) is the main pathogenesis of metabolic syndrome and a shared pathophysiological change in conditions such as diabetes mellitus, adiposity, hypertension, and atherosclerosis. Visceral adipose tissue-derived serpin (Vaspin) is a newly discovered adipocytokine with insulin-sensitizing and anti-inflammatory effects. To examine if vaspin can improve insulin resistance in rats fed a high-fat diet via the insulin receptor substrate/phosphatidylinositol 3 kinase/protein kinase B/glucose transport (IRS/PI3K/Akt/Glut) and inhibitory κB alpha/nuclear factor-kappa B (IκBα/NF-κB) signalling pathways, thirty male Sprague-Dawley (SD) rats were randomly divided into three groups: the normal control group (NC group, n = 10), high-fat diet group (HFD group, n = 10) and vaspin intervention group (HFD + vaspin group, n = 10). Results showed that intervention with vaspin significantly decreased fasting blood glucose (FBG) and fasting insulin (FINS) concentrations in HFD − fed rats without significantly affecting body weight or triglyceride (TG) or total cholesterol (TC) levels. The areas under the intraperitoneal glucose tolerance test (IPGTT) and the insulin tolerance test (ITT) curves were significantly decreased in HFD + vaspin group compared with the HFD group, and the glucose infusion rate (GIR) showed the same trends. Western blot, real-time polymerase chain reaction (RT-PCR) and immunofluorescence staining showed that vaspin could improve insulin resistance in liver, skeletal muscle and adipose tissue by activating the IRS/PI3K/Akt/Glut signalling pathway and inhibiting the IκBα/NF-κB signalling pathway.

Novel adipokines vaspin and irisin as risk biomarkers for cardiovascular diseases in type 2 diabetes mellitus

AIMS

Vaspin and irisin are novel cytokines proposed as potential new biomarkers of insulin resistance and endothelial dysfunction. This work is to investigate circulating levels of vaspin and irisin in patients with type 2 diabetes mellitus (T2DM) with and without cardiovascular disease (CVD) to study potential association with disease risk.

MATERIALS AND METHODS

Circulating levels of vaspin and irisin were assayed in serum from 135 T2DM patients (with and without CVD) and 70 control subjects by ELISA.

RESULTS

Vaspin levels were significantly higher in T2DM patients than in control subjects (6798 ± 3540 pg/ml vs. 3215 ± 3209 pg/ml, p = 0.001) and in CVD patients than in non-CVD patients (7417.3 ± 3507.6 pg/ml vs. 6017.3 ± 3606.4 pg/ml, p = 0.001), with significant positive correlations with BMI, FPG, serum insulin and HOMA-IR. Irisin levels were significantly lower in T2DM patients than in controls (71.15 ± 67.57 ng/ml vs.127 ± 71.57 ng/ml, p = 0.004), and in CVD patients than in non-CVD patients (55.77 ± 54.82 ng/ml vs. 115.5 ± 67 ng/ml, p = 0.003), with significant correlations with HbA1c, HOMA-IR and BMI in diabetic patients, and with HbA1c and TG in CVD patients. Elevated levels of vaspin was associated with 1.7 times increased CVD risk (p = 0.001, OR = 1.7, 95%CI = 1.21-2.39), while lower levels of irisin associated with 1.6 times increased CVD risk (p = 0.007, OR = 1.6, 95%CI = 1.45-2.28). ROC analysis indicated serum vaspin and irisin as independent CVD risk biomarkers with sensitivity, 94% and 73.7%, and specificity, 74% and 74.1%; respectively.

CONCLUSION

Our results indicate that circulating vaspin and irisin are potential new independent CVD risk biomarkers in T2DM.

The role of obesity and adipose tissue dysfunction in gestational diabetes mellitus

Gestational diabetes mellitus is defined as diabetes diagnosed in the second or third trimester of pregnancy in patients with no history of diabetes prior to gestation. It is the most common complication of pregnancy. The underlying pathophysiology shares some common features with type 2 diabetes mellitus (T2DM) combining relatively insufficient insulin secretion with increased peripheral insulin resistance. While a certain degree of insulin resistance is the physiological characteristics of the second half of pregnancy, it is significantly more pronounced in patients with gestational diabetes. Adipose tissue dysfunction and subclinical inflammation in obesity are well-described causes of increased insulin resistance in non-pregnant subjects and are often observed in individuals with T2DM. Emerging evidence of altered adipokine expression and local inflammation in adipose tissue in patients with gestational diabetes suggests an important involvement of adipose tissue in its etiopathogenesis. This review aims to summarize current knowledge of adipose tissue dysfunction and its role in the development of gestational diabetes. We specifically focus on the significance of alterations of adipokines and immunocompetent cells number and phenotype in fat. Detailed understanding of the role of adipose tissue in gestational diabetes may provide new insights into its pathophysiology and open new possibilities of its prevention and treatment.

The correlation between serum adipokines levels and metabolic indicators in girls with Turner syndrome

OBJECTIVE

The following study investigated the serum adiponectin, chemerin and vaspin levels and their relationship with body mass index (BMI), glucose and lipid metabolism in girls with Turner Syndrome (TS).

METHODS

A total of 64 girls with TS (mean age, 12.22 ± 3.98 years; mean BMI, 18.90 ± 3.45 kg/m²) were ascertained by chromosome analysis. Height, weight, waist circumference, hip circumference and blood pressure were measured, as well as the levels of fasting plasma glucose (FPG), fasting plasma insulin, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG). The BMI, BMI standard deviation score (SDS), waist to hip ratio, waist to height ratio and insulin resistance index (HOMA-IR) were calculated. The TS group and the control group were subdivided into non-puberty or puberty subgroup.

RESULTS

The TS group had higher waist to hip ratio and waist to height ratio compared to the control group. There was no significant difference in FPG, fasting plasma insulin, HOMA-IR, blood lipid and blood pressure between the two groups. Significantly higher serum levels of adioponectin (12.51 ± 4.58 μg/ml) and chemerin (173.71 ± 37.88 ng/ml) and significantly lower levels of vaspin (0.67 ± 0.47 ng/ml) were found in the TS group compared to the control group (9.30 ± 3.17 μg/ml, 159.43 ± 23.19 ng/ml and 1.06 ± 0.49 ng/ml, respectively) (all P < 0.05). In the TS group, adiponectin levels were negatively correlated with age, BMI and TG (r = -0.251, -0.247, -0.294, P < 0.05 for all). In the control group, adiponectin levels were negatively correlated with BMI and BMI SDS (r = -0.416 and -0.315, P < 0.05 for both), while vaspin levels were positively correlated with age, fasting plasma insulin and HOMA-IR (r = 0.257, 0.273 and 0.282, P < 0.05 for all). In addition, significantly higher levels of adiponectin were found in the non-puberty subgroup (13.88 ± 4.49) μg/ml compared to puberty subgroup (9.72 ± 3.39) μg/ml (P < 0.05), while no significant differences in chemerin and vaspin were found between the two TS subgroups.

CONCLUSIONS

Elevated adiponectin and chemerin levels and significantly reduced vaspin were found in girls with TS. Puberty or estrogen replacement therapy may reduce adiponectin in girls with TS.

Molecular Mechanisms of Vaspin Action - From Adipose Tissue to Skin and Bone, from Blood Vessels to the Brain

Visceral adipose tissue-derived serine protease inhibitor (vaspin) or SERPINA12 according to the serpin nomenclature was identified together with other genes and gene products that were specifically expressed or overexpressed in the intra-abdominal or visceral adipose tissue (AT) of the Otsuka Long-Evans Tokushima fatty rat. These rats spontaneously develop visceral obesity, insulin resistance, hyperinsulinemia and -glycemia, as well as hypertension and thus represent a well suited animal model of obesity and related metabolic disorders such as type 2 diabetes.The follow-up study reporting the cloning, expression and functional characterization of vaspin suggested the great and promising potential of this molecule to counteract obesity induced insulin resistance and inflammation and has since initiated over 300 publications, clinical and experimental, that have contributed to uncover the multifaceted functions and molecular mechanisms of vaspin action not only in the adipose, but in many different cells, tissues and organs. This review will give an update on mechanistic and structural aspects of vaspin with a focus on its serpin function, the physiology and regulation of vaspin expression, and will summarize the latest on vaspin function in various tissues such as the different adipose tissue depots as well as the vasculature, skin, bone and the brain.

Immunologic and endocrine functions of adipose tissue: implications for kidney disease

Excess adiposity can induce adverse sequelae in multiple cell types and organ systems. The transition from the lean to the obese state is characterized by fundamental cellular changes at the level of the adipocyte. These changes affect the local microenvironment within the respective adipose tissue but can also affect nonadipose systems. Adipocytes within fat pads respond to chronic nutrient excess through hyperplasia or hypertrophy, which can differentially affect interorgan crosstalk between various adipose depots and other organs. This crosstalk is dependent on the unique ability of the adipocyte to coordinate metabolic adjustments throughout the body and to integrate responses to maintain metabolic homeostasis. These actions occur through the release of free fatty acids and metabolites during times of energy need - a process that is altered in the obese state. In addition, adipocytes release a wide array of signalling molecules, such as sphingolipids, as well as inflammatory and hormonal factors (adipokines) that are critical for interorgan crosstalk. The interactions of adipose tissue with the kidney - referred to as the adipo-renal axis - are important for normal kidney function as well as the response of the kidney to injury. Here, we discuss the mechanistic basis of this interorgan crosstalk, which clearly has great therapeutic potential given the increasing rates of chronic kidney disease secondary to obesity and type 2 diabetes mellitus.

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.

The role of vaspin as a predictor of coronary angiography result in SCAD (stable coronary artery disease) patients

BACKGROUND

The role of vaspin in the pathogenesis of stable coronary artery disease (SCAD) have been repeatedly addressed in clinical studies. However, from the point of view of clinical practice, the results of earlier studies are still inconclusive.

METHODS

The data of 106 SCAD patients who received coronary angiography and 85 coronary artery disease-free controls were collected and analysed. The patients were divided into subgroups according to their pre-test probability (PTP) and according to the result of coronary angiography. Fasting vaspin concentrations were compared between subgroups of SCAD patients and between target group and controls. The effect of age and smoking on the result of coronary angiography was compared to the effect of vaspin using the binomial regression.

RESULTS

We did not find significant difference in vaspin level between target group and controls. Unless the pre-test probability was taken into account, we did not find vaspin difference in the target group, when dividing patients on the basis of presence/absence of significant coronary stenosis. In the subgroup of SCAD patients with PTP between 15% - 65%, those with significant coronary stenoses had higher mean vaspin concentration (0,579 ± 0,898 ng/ml) than patients without significant stenoses. (0,379 ± 0,732 ng/ml) (t = -2595; p = 0,012; d = 0,658; 1-β = 0,850). Age, smoking status and vaspin significantly contributed to the HSCS prediction in binomial regression model in patients with low PTP (OR: 1.1, 4.9, 8.7, respectively).

CONCLUSION

According to our results, vaspin cannot be used as an independent marker for the presence of CAD in general population. However, our results indicate that measuring vaspin in SCAD patients might be clinically useful in patients with PTP below 66%.

Obesity risk prediction among women of Upper Egypt: The impact of serum vaspin and vaspin rs2236242 gene polymorphism

BACKGROUND

Vaspin is an adipokine that is potentially linking obesity, insulin resistance, metabolic syndrome and type-2 diabetes.

AIM

The present study aimed to investigate the impact of vaspin rs2236242 gene polymorphism on the risk of obesity, diabetes, their metabolic traits, and serum vaspin levels in a sample of Upper Egyptian women.

SUBJECTS AND METHODS

A total of 224 subjects, 112 obese (62 non diabetics, 50 diabetics) and 112 controls were included in this case control study. Vaspin gene rs2236242 polymorphism was performed using tetra-amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) and serum vaspin levels were estimated by ELISA.

RESULTS

The minor (A) allele of vaspin rs2236242 gene polymorphism was significantly lower in obese (30.8%) than controls (43.7%) (P=0.005). The protective effect was evident in dominant and recessive inheritance models (TT vs TA+AA, P=0.004 and TT+TA vs AA, P=0.036). After adjusting genotypes for diabetes there were no significant association between vaspin rs2236242 gene polymorphism and obesity but significant association was maintained in the obese diabetics. Vaspin serum levels were found to be lower in minor protective (AA) genotype carriers than the other two genotypes (P<0.001). In the mean-time serum vaspin levels were significantly higher in obese diabetics and non-diabetics than controls (P<0.001 each).There were significant positive correlations between vaspin levels and hs-CRP, cholesterol, LDL-C, fasting glucose, HOMA-IR, insulin, and ALT values (P<0.05 each) and a negative correlation with HDL-C (P<0.01).

CONCLUSION

The minor A allele of vaspin rs2236242 polymorphism plays a protective role against obesity and diabetes but this relation is largely ascribed to its effect on insulin resistance. The serum vaspin concentration was lower in minor protective allele carriers. To the best of our knowledge, this is the first study of vaspin SNP in Upper Egyptian women. The entire understanding of vaspin intimate mechanistic action might enable the development of novel etiology-based treatment strategies for obesity, the complex genetic trait.

Adipokines and cardiovascular disease: A comprehensive review

Adipokines are peptides that signal the functional status of adipose tissue to the brain and other target organs. In adipose tissue dysfunction, adipokine secretion is altered, and this can contribute to a spectrum of obesity-associated conditions including cardiovascular disease. Some adipokines have anti-inflammatory and cardioprotective effects (omentin, apelin, adiponectin). Others are pro-inflammatory with negative impact on cardiovascular function (leptin, visfatin, resistin, adipocyte fatty-acid-binding protein). In the first part, this article reviews the endocrine functions of adipose tissue in general, effects of the distribution and composition of fat tissue, and the roles of cortisol and the renin-angiotensin-aldosterone system in the development of the inflammatory state of addipose tissue. In the second part, the known cardiovascular effects of different adipokines and their clinical potential are discussed in detail.

Medullary Thyroid Carcinoma--Circulating Status of Vaspin and Retinol Binding Protein-4 in Iranian Patients

BACKGROUND

Vaspin and Retinol binding protein-4 (RBP4) are new adipokines mainly produced by adipose tissue. Considering that medullary thyroid carcinoma (MTC) is a malignant neuroendocrine tumor, and to date the relationship between serum levels of vaspin and RBP4 with MTC has not been studied, in this matched case-control study we evaluated their possible significance to this tumor type.

MATERIALS AND METHODS

A total of 45 patients with MTC (21 males and 24 females) and 45 healthy persons as a control group (24 males and 21 females) were selected. The two groups were matched for age, sex and body mass index. Serum Vaspin and RBP4 levels were measured by enzyme-linked immunosorbent assay (ELISA) methods in both groups. Also, weight and height were measured and body mass index was calculated too.

RESULTS

In total, patients with MTC had significantly higher serum vaspin levels compared to the controls (0.52 ng/ml vs. 0.45 ng/ml, P=0.0241). However, no significant difference was found in serum RBP4 concentrations between the patients with MTC and the controls (15.2±2.55 μg/ml versus 15.1±3.34 μg/ml, p>0.05).

CONCLUSIONS

The results of this study demonstrated that serum RBP4 levels in MTC patients are not significantly different from those found in healthy individuals and did not correlate with MTC. On the other hand, higher levels of serum vaspin are associated with an increased risk of MTC. Thus Vaspin may be a novel and promising biomarker for diagnosis or confirmation of MTC in conjunction other specific tumor markers.

Relationships of Dietary Histidine and Obesity in Northern Chinese Adults, an Internet-Based Cross-Sectional Study

Our previous studies have demonstrated that histidine supplementation significantly ameliorates inflammation and oxidative stress in obese women and high-fat diet-induced obese rats. However, the effects of dietary histidine on general population are not known. The objective of this Internet-based cross-sectional study was to evaluate the associations between dietary histidine and prevalence of overweight/obesity and abdominal obesity in northern Chinese population. A total of 2376 participants were randomly recruited and asked to finish our Internet-based dietary questionnaire for the Chinese (IDQC). Afterwards, 88 overweight/obese participants were randomly selected to explore the possible mechanism. Compared with healthy controls, dietary histidine was significantly lower in overweight (p < 0.05) and obese (p < 0.01) participants of both sexes. Dietary histidine was inversely associated with body mass index (BMI), waist circumference (WC) and blood pressure in overall population and stronger associations were observed in women and overweight/obese participants. Higher dietary histidine was associated with lower prevalence of overweight/obesity and abdominal obesity, especially in women. Further studies indicated that higher dietary histidine was associated with lower fasting blood glucose (FBG), homeostasis model assessment of insulin resistance (HOMA-IR), 2-h postprandial glucose (2 h-PG), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), C-reactive protein (CRP), malonaldehyde (MDA) and vaspin and higher glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and adiponectin of overweight/obese individuals of both sexes. In conclusion, higher dietary histidine is inversely associated with energy intake, status of insulin resistance, inflammation and oxidative stress in overweight/obese participants and lower prevalence of overweight/obesity in northern Chinese adults.

Vaspin prevents elevation of blood pressure through inhibition of peripheral vascular remodelling in spontaneously hypertensive rats

AIM

Visceral adipose tissue-derived serine protease inhibitor (vaspin) is a relatively novel adipocytokine with protective effects on metabolic diseases including obesity and type II diabetes. We have previously demonstrated that vaspin exerts anti-inflammatory and antimigratory roles through antioxidative effects in vascular smooth muscle cells. As inflammatory responses and migration of smooth muscle in peripheral vascular wall are key mechanisms for the pathogenesis of hypertension, we hypothesized that vaspin could prevent the development of hypertension in in vivo hypertensive animal model.

METHODS

Vaspin (1 μg kg(-1)  day(-1) ) was administered intraperitoneally to 5-week-old male spontaneously hypertensive rats (SHR) for 4 weeks. Superior mesenteric artery was isolated and used for measurement of isometric contraction and histological analysis.

RESULTS

Long-term vaspin treatment significantly prevented an elevation of systolic blood pressure (SBP) at 8 weeks of age. Vaspin had no effect on reactivity of isolated mesenteric artery from SHR. In contrast, vaspin significantly inhibited mesenteric arterial wall hypertrophy in SHR. Moreover, vaspin significantly inhibited an increase of tumour necrosis factor-α expression and a production of reactive oxygen species in isolated mesenteric artery from SHR.

CONCLUSION

This study for the first time demonstrates that vaspin prevents the increase of SBP in SHR through inhibiting peripheral vascular hypertrophy possibly via antioxidative and anti-inflammatory mechanisms.

Association between vaspin level and coronary artery disease in patients with type 2 diabetes

AIM

Adipokines contribute to the atherosclerotic process, connecting obesity and diabetes to cardiovascular disease. Vaspin is a recently discovered adipokine, so data about the relationship of vaspin to coronary artery disease in type-2 diabetes mellitus (T2DM) is limited. The current study was designed to evaluate the association of vaspin with the presence of coronary artery disease in T2DM.

METHODS

We enrolled 228 patients with T2DM, with or without CAD, between March 2010 and July 2011, and 120 healthy control participants. Serum vaspin, homeostasis model assessment of insulin resistance (HOMA-IR) and other cardiovascular risk factors were assayed.

RESULTS

Vaspin levels were significantly increased in patients with T2DM compared to healthy individuals, and were further increased in patients with both T2DM and CAD compared to those with T2DM but without CAD. Moreover, vaspin correlated positively with body mass index, fasting plasma glucose, insulin and HOMA-IR in all patients with T2DM (P<0.05). Furthermore, in multivariate logistic regression analysis, vaspin level was associated with the presence of CAD in patients with T2DM.

CONCLUSIONS

Vaspin correlates with CAD in T2DM.

Visceral adipose tissue-derived serine protease inhibitor augments acetylcholine-induced relaxation via the inhibition of acetylcholine esterase activity in rat isolated mesenteric artery

AIM

Visceral adipose tissue-derived serine protease inhibitor (vaspin) is an adipocytokine with insulin-sensitizing activity originally identified in visceral adipose tissues of obesity-related type II diabetic rats. We previously showed that vaspin inhibits vascular cell migration and apoptosis as well as inflammatory responses, which are crucial for the development of hypertension. However, little is known about the effects of vaspin on vascular reactivity. The aim of this study was thus to explore the effects of vaspin on contraction and relaxation of isolated blood vessel.

METHODS

After mesenteric arteries were isolated from male Wistar rats, the effects of pretreatment with vaspin (3 ng mL(-1) , 30 min) on concentration-contraction and concentration-relaxation relationships for each agent were examined. The effects of vaspin on acetylcholine (ACh)-induced phosphorylation of endothelial nitric oxide (NO) synthase (eNOS) and ACh esterase (AChE) activity were also examined using Western blotting and colorimetric method respectively.

RESULTS

Vaspin did not affect noradrenaline- or 5-hydroxytryptamine-induced contraction. In contrast, vaspin augmented ACh- but not histamine-, A23187- or carbachol-induced NO-mediated relaxation. Vaspin significantly increased ACh-induced eNOS phosphorylation and inhibited AChE activity.

CONCLUSION

We for the first time demonstrate that vaspin augments the ACh-induced NO-mediated endothelium-dependent relaxation via the inhibition of AChE activity.

Biomarkers of Metabolic Syndrome: Biochemical Background and Clinical Significance

Biomarkers of the metabolic syndrome are divided into four subgroups. Although dividing them in groups has some limitations, it can be used to draw some conclusions. In a first part, the dyslipidemias and markers of oxidative stress are discussed, while inflammatory markers and cardiometabolic biomarkers are reviewed in a second part. For most of them, the biochemical background and clinical significance are discussed, although here also a well-cut separation cannot always be made. Altered levels cannot always be claimed as the cause, risk, or consequence of the syndrome. Several factors are interrelated to each other and act in a concerted, antagonistic, synergistic, or modulating way. Most important conclusions are summarized at the end of every reviewed subgroup. Genetic biomarkers or influences of various food components on concentration levels are not included in this review article.

Is vaspin related to cardio-metabolic status and autonomic function in early stages of glucose intolerance and in metabolic syndrome?

BACKGROUND

This study aims to assess serum vaspin in early stages of glucose intolerance and in the presence of metabolic syndrome (MetS); and to evaluate vaspin correlation to different cardio-metabolic parameters and autonomic tone in these subjects.

METHODS

185 subjects (80 males and 105 females) of mean age 45.8 ± 11.6 years and mean BMI 31.2 ± 6.3 kg/m(2), divided into groups according to: glucose tolerance, presence of MetS and cardio-vascular autonomic dysfunction (CAD), were enrolled. Glucose tolerance was studied during OGTT. Anthropometric indices, blood pressure, HbA1c, serum lipids, hsCRP, fasting immunoreactive insulin and serum vaspin were measured. Body composition was estimated by impedance analysis. AGEs were assessed by skin fluorescence. CAD was assessed by ANX-3.0.

RESULTS

There was no difference in vaspin levels between the groups according to glucose tolerance, presence of MetS, and CAD. Regression analysis revealed independent association between serum vaspin and total body fat in newly diagnosed type 2 diabetes (NDT2D) group, and between serum vaspin and age and total body fat in MetS group. Vaspin negatively correlated with both sympathetic and parasympathetic activity in normal glucose tolerance (NGT) and just with parasympathetic tone in NGT without MetS.

CONCLUSION

Our results demonstrate no overt fluctuations in vaspin levels in the early stages of glucose intolerance and in MetS. Total body fat seems to be related to vaspin levels in MetS and NDT2D. Our data show negative correlation between vaspin and autonomic function in NGT, as vaspin is associated with parasympathetic activity even in the absence of MetS.

Association of circulating adipokines with metabolic dyslipidemia in obese versus non-obese individuals

AIM

Previous studies have shown that circulating adipokines may play an important role in the pathogenesis of some obesity related chronic disease such as dyslipidemia and type2 diabetes mellitus. The aim of the present study was to investigate the association between vaspin, omentin-1 and retinol binding protein-4 levels with metabolic dyslipidemia (MD) criteria in obese and non-obese individuals.

METHOD

The study was conducted on 170 obese and 81 non-obese individuals. After collecting the blood samples, serum levels metabolic parameters as well as three circulating adipokines and body composition were measured.

RESULTS

No significant difference was noted regarding the mean serum levels of omentin-1 and vaspin between the obese and non-obese groups, while, serum level of RBP4 was significantly higher in the non-obese group. We found the 0.22 increased risk of MD in obese individuals with higher RBP4 concentration. After the adjustment for confounding factors, this association was still significant. No significant association was noted between MD and its components relative risks with omentin-1 and vaspin levels.

CONCLUSION

Our study demonstrated that circulating RBP4 was significantly higher in the obese individuals which may increase the risk of MD in them. Further researches are needed to address this association.

The role of vaspin in the development of metabolic and glucose tolerance disorders and atherosclerosis

In recent years, most research efforts have been focused on studying insulin-sensitizing adipokines. One of the most recently discovered adipokines is vaspin, a visceral adipose tissue-derived serine protease inhibitor. Vaspin levels have been found significantly increased in mice with obesity and insulin resistance. It has been assumed that vaspin serves as an insulin sensitizer with anti-inflammatory effects and might act as a compensatory mechanism in response to decreased insulin sensitivity. Most studies in humans have shown a positive correlation between vaspin gene expression and serum levels, and metabolic syndrome parameters. Vaspin gene expression is influenced by age and gender, and the administration of insulin sensitizers enhances it in mice, whereas the use of metformin decreases serum vaspin levels in humans, probably due to different regulatory mechanisms. Presumably vaspin plays local and endocrine role in the development of initial and advanced atherosclerosis in obese subjects and might be used as a predictor of coronary and cerebrovascular disease. It is believed that vaspin could be regarded as a new link between obesity and related metabolic disorders, including glucose intolerance. The entire understanding of vaspin intimate mechanism of action might enable the development of novel etiology-based treatment strategies, targeting metabolic and glucose tolerance disorders.