Increased serum visfatin in patients with metabolic syndrome and carotid atherosclerosis

Extracellular nicotinamide phosphoribosyltransferase: role in disease pathophysiology and as a biomarker

Nicotinamide phosphoribosyltransferase (NAMPT) plays a central role in mammalian cell metabolism by contributing to nicotinamide adenine dinucleotide biosynthesis. However, NAMPT activity is not limited to the intracellular compartment, as once secreted, the protein accomplishes diverse functions in the extracellular space. Extracellular NAMPT (eNAMPT, also called visfatin or pre-B-cell colony enhancing factor) has been shown to possess adipocytokine, pro-inflammatory, and pro-angiogenic activities. Numerous studies have reported the association between elevated levels of circulating eNAMPT and various inflammatory and metabolic disorders such as obesity, diabetes, atherosclerosis, arthritis, inflammatory bowel disease, lung injury and cancer. In this review, we summarize the current state of knowledge on eNAMPT biology, proposed roles in disease pathogenesis, and its potential as a disease biomarker. We also briefly discuss the emerging therapeutic approaches for eNAMPT inhibition.

The Value of Visfatin in the Prediction of Metabolic Syndrome: A Systematic Review and Meta-Analysis

Various studies have shown that visfatin may be connected to metabolic syndrome (MS). However, epidemiological studies yielded conflicting outcomes. The purpose of this article was to highlight the relationship between the plasma visfatin level and MS risk by conducting a meta-analysis of available literature. A comprehensive literature search of eligible studies was done up to January 2023. Data were presented as standard mean difference (SMD). Observational methodological meta-analysis was conducted to assess the relationships between visfatin levels and MS. The visfatin levels between patients with MS or not were calculated by SMD and 95% confidence interval (CI) using the random-effects model. Funnel plot (visually inspect publication bias), Egger's linear regression test and Begger's linear regression test were applied to describe the risk of publication bias. A sensitivity analysis was performed via sequentially omitting each of the study one by one. In total, 16 eligible studies comprising 1016 cases and 1414 healthy controls finally enrolled in the current meta-analysis for pooling meta-analysis. Overall, the meta-analysis results revealed that visfatin levels in MS patients were significantly greater than that of controls group (SMD: 0.60, 95% CI=0.18-1.03, I2=95%, p<0.001). The results of the subgroup analysis showed that gender did not affect the results of meta-analysis. This meta-analysis shed light on the fact that circulating visfatin levels were significantly higher in patients with MS than in the controls group. Visfatin may a chance to predict the occurrence of MS.

Visfatin and Subclinical Atherosclerosis in Type 2 Diabetes: Impact of Cardiovascular Drugs

Background and Objectives: The role of adipokines in the development of atherosclerosis in type 2 diabetes (T2DM) has not yet been fully elucidated. The effects of drugs on adipokine concentrations have only been evaluated in very few studies, although they may be of clinical importance. This study aimed to assess whether the concentrations of circulating adipokines could predict subclinical atherosclerosis in patients with T2DM, as well as their interactions with commonly used cardiovascular drugs. Materials and Methods: Our population-based cross-sectional multicentric study included 216 participants with T2DM but without previously diagnosed atherosclerosis. The carotid artery intima-media thickness (IMT), plaque and ankle-brachial index (ABI) metrics were measured. Resistin, visfatin, retinol-binding protein 4, high molecular weight adiponectin and leptin levels were evaluated using Luminex's xMAP technology. Results: Visfatin and resistin concentrations correlated positively with IMT (p = 0.002 and p = 0.009, respectively). The correlation of visfatin to IMT ≥ 1.0 mm was significant in males (p < 0.001). Visfatin had a positive correlation with IMT ≥ 1.0 mm or plaque (p = 0.008) but resistin only correlated with plaque (p = 0.049). Visfatin predicted IMT ≥ 1.0 mm or plaque in patients on β-blocker monotherapy (p = 0.031). Visfatin lost its ability to predict subclinical atherosclerosis in patients taking angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, calcium channel blockers or statins. After adjustments for risk factors for atherosclerosis and cardiovascular drugs, visfatin maintained an independent association with mean IMT (p = 0.003), IMT ≥ 1.0 mm or plaque (p = 0.005) and ABI ≤ 0.9 (p = 0.029). Conclusions: Visfatin could be used as a marker of subclinical atherosclerosis in patients with T2DM, especially in males. The assessment of visfatin concentration could aid in identifying individuals who could benefit from implementing preventive measures against atherosclerosis.

Hormonal regulation of visfatin and adiponectin system in quail muscle cells

Visfatin and adiponectin are two adipokines known to regulate energy homeostasis and stress response within different peripheral tissues. Their role and regulation in highly metabolically active tissue such as the muscle is of particular interest. As modern poultry exhibit insulin resistance, obesity, and hyperglycemia along with a lack of insight into the regulation of these avian adipokines, we undertook the present work to determine the regulation of visfatin and adiponectin system by cytokines and obesity-related hormones in a relevant in vitro model of avian muscle, quail muscle (QM7) cells. Cells were treated with pro-inflammatory cytokine IL-6 (5 and 10 ng/mL) and TNFα (5 and 10 ng/mL), as well as leptin (10 and 100 ng/mL) and both orexin-A and orexin-B (ORX-A/B) (5 and 10 ng/mL). Results showed significant increases in visfatin mRNA abundance under both cytokines (IL-6 and TNFα), and down regulation with ORX-B treatment. Adiponectin expression was also upregulated by pro-inflammatory cytokines (IL-6 and TNFα), but down regulated by leptin, ORX-A, and ORXB. High doses of IL-6 and TNFα up regulated the expression of adiponectin receptors AdipoR1 and AdipoR2, respectively. Leptin and orexin treatments also down regulated both AdipoR1 and AdipoR2 expression. Taken together, this is the first report showing a direct response of visfatin and the adiponectin system to pro-inflammatory and obesity-related hormones in avian muscle cells.

Role of adipokines (omentin and visfatin) in coronary artery disease

AIMS

Adipose tissue is considered as an endocrine organ that releases bioactive factors known as adipokines which contribute to the pathogenesis of rotundity-linked metabolic and cardiovascular complications. Rotundity is a major predisposer for the development and progression of coronary artery disease (CAD).

DATA SYNTHESIS

The literature survey from various databases such as Pubmed/Medline, DOAJ, Scopus, Clarivate analytics/Web of Science and Google Scholar were used to prepare this article. The epidemic of rotundity has gained significant attention to understand the biology of adipocytes and the metabolism of adipose tissue in obese individuals. In CAD, visfatin/NAMPT was primarily indicated as a clinical marker of atherosclerosis, endothelial dysfunction and vascular injury having a prognostic significance. Visfatin/NAMPT is a factor that promotes vascular inflammation and atherosclerosis. Omentin is an anti-inflammatory and anti-atherogenic adipokine regulating cardiovascular functions.

CONCLUSIONS

This review highlights and summarizes the scientific information pertaining to the role of the adipokines - omentin and visfatin in CAD.

Evaluation of the adipokine levels of pregnant women with preeclampsia

AIM

The aim of this study was to compare maternal blood and umbilical-cord leptin, spexin and visfatin levels during delivery in severe preeclampsia (PE) with controls, and to evaluate whether any clinical or demographic variables had independent associations with them.

METHODS

This is a case-controlled observational study consisting of 45 pregnant women with severe PE and a control group consisting of gestational age-matched 45 healthy pregnant women. We examined the leptin, spexin, and visfatin levels in serum samples taken from maternal blood and umbilical cords during cesarean section in both groups. Leptin, spexin, and visfatin levels were measured by enzyme-linked immunosorbent assay.

RESULTS

The maternal leptin and visfatin levels were significantly higher and the maternal spexin levels were significantly lower in the PE group than in the control group (p < 0.001). Similar to the maternal adipokine levels, the umbilical-cord leptin and visfatin levels were significantly higher and the spexin levels were significantly lower in the PE group (p < 0.001). We found a significant positive correlation between maternal body mass index and maternal blood and umbilical-cord serum leptin and visfatin levels in both groups (p < 0.001).

CONCLUSION

The leptin, spexin and visfatin levels were significantly altered in the nondiabetic preeclamptic women in our study. We believe that the main reason for these changes may be the hypoxic placenta to protect the fetus and maintain its nutrition.

Adipokines: Deciphering the cardiovascular signature of adipose tissue

Obesity and hypertension are intimately linked due to the various ways that the important cell types such as vascular smooth muscle cells (VSMC), endothelial cells (EC), immune cells, and adipocytes, communicate with one another to contribute to these two pathologies. Adipose tissue is a very dynamic organ comprised primarily of adipocytes, which are well known for their role in energy storage. More recently adipose tissue has been recognized as the largest endocrine organ because of its ability to produce a vast number of signaling molecules called adipokines. These signaling molecules stimulate specific types of cells or tissues with many adipokines acting as indicators of adipocyte healthy function, such as adiponectin, omentin, and FGF21, which show anti-inflammatory or cardioprotective effects, acting as regulators of healthy physiological function. Others, like visfatin, chemerin, resistin, and leptin are often altered during pathophysiological circumstances like obesity and lipodystrophy, demonstrating negative cardiovascular outcomes when produced in excess. This review aims to explore the role of adipocytes and their derived products as well as the impacts of these adipokines on blood pressure regulation and cardiovascular homeostasis.

Inflammatory markers are associated with the progression of gestational diabetes to metabolic syndrome

The progression of gestational diabetes mellitus (GDM) to metabolic syndrome (MetS) is associated with systemic inflammation. The aim of this study was to compare the levels of inflammatory markers in former GDM patients with and without MetS. Medical records were screened retrospectively for patients who were diagnosed with GDM 10 (±2) years ago. Former GDM patients were invited to the hospital for an assessment of their current health status. Of 52 women with former GDM, 27 (52%) had MetS. C-reactive protein (CRP), interleukin-6 and plasminogen activator inhibitor-1 (PAI-1) levels were significantly higher in the MetS group while adiponectin was significantly lower (p < .001, p = .037, p = .002 and p = .013, respectively). There was no significant difference in plasma levels of visfatin and tumour necrosis factor-α. Interleukin-6, CRP, PAI-1 and adiponectin may be used as biomarkers to detect MetS in the pre-clinical phase. With timely diagnosis, early interventions can be implemented. IMPACT STATEMENTWhat is already known on this subject? The progression of 'gestational diabetes mellitus' to 'metabolic syndrome' is associated with systemic inflammation. Up to half of cases with former gestational diabetes mellitus (GDM) eventually progress to metabolic syndrome (MetS).What do the results of this study add? Interleukin-6, C-reactive protein, plasminogen activator inhibitor-1 and adiponectin may be used as biomarkers to detect MetS in the pre-clinical phase.What are the implications of these findings from clinical practice and/or further research? The progression of GDM to MetS is associated with systemic inflammation. Potential therapies should therefore target this inflammatory state. Interleukin-6, C-reactive protein, plasminogen activator inhibitor-1 and adiponectin may be used as biomarkers to detect MetS in the pre-clinical phase. With timely diagnosis, early interventions and lifestyle changes can be implemented to prevent morbidity and mortality associated with full-blown MetS.

GLUT4 gene rs5418 polymorphism is associated with increased coronary heart disease risk in a Uygur Chinese population

Background

To explore possible associations between glucose transporter 4 (GLUT4) genetic polymorphisms in the patients with coronary heart disease (CHD) in Han and Uygur Chinese populations in Xinjiang, China.

Methods

Two GLUT4 polymorphisms (rs5418 and rs5435) were genotyped in 1262 Han (628 CHD patients and 634 healthy controls) and 896 Uyghur (397 CHD patients and 499 healthy controls) Chinese populations.

Results

In the Han Chinese population, there were no significant differences in allelic or genotypic distribution of rs5418 and rs5435 between the CHD and control groups (all P > 0.05). However, in the Uygur population, there were significant differences in genotype and allele distributions for rs5418 between CHD and the control group (all P < 0.05). Binary Logistic regression analysis showed that carriers with the rs5418 A allele had a higher risk of CHD compared to carriers of the rs5418 G allele (OR = 1.33, 95% CI: 1.069–1.649, P = 0.01), after adjustment for gender, age, drinking and smoking behavior, hypertension and diabetes. Furthermore, haploid association analysis of the two SNP loci of the GLUT4 gene showed that the AC haplotype was associated with CHD in the Uygur population (P = 0.001598; OR = 1.36, 95% CI = 1.1228–1.6406).

Conclusions

rs5418 GLUT4 gene variants are associated with CHD in the Uygur Chinese population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02630-9.

Visfatin as a Promising Marker of Cardiometabolic Risk

Adipose tissue is an endocrine organ that produces molecules with important functions in the human body called adipokines. Visfatin can be secreted from various sources, such as macrophages, chondrocytes and amniotic epithelial cells other than adipose tissue. The main effect of visfatin is to promote inflammatory processes. In addition, visfatin has pivotal effects on the entire cardiovascular system, such as endothelial dysfunction, atherosclerosis, plaque rupture and mobilization, myocardial damage, fibrosis and new vessel formation. Vascular pathologies in other tissues also mediate its effects. Visfatin changes in a similar manner to cardiac markers in acute myocardial infarction, and the most cited feature in research studies is that it may be a cardiovascular risk marker. Visfatin is therefore expected to be widely used in cardiovascular pathology in the near future. Visfatin has many target tissues and various effects that occur in relatively complex biological pathways, making it difficult to understand visfatin adequately. In this review, we provide comprehensive information about this promising molecule.

The relationship of serum visfatin levels with clinical parameters, flow-mediated dilation, and carotid intima-media thickness in patients with ankylosing spondylitis

Background/aim

Atherosclerotic heart diseases can occur at an early age in patients with ankylosing spondylitis (AS). Flow-mediated dilation (FMD) and carotid intima-media thickness (cIMT) values are reliable markers for early detection of subclinical atherosclerosis in patients with AS. We aimed to investigate the relationship between visfatin levels and indirect markers of subclinical atherosclerosis and endothelial dysfunction in patients with AS.

Materials and methods

Forty-two patients diagnosed with AS and 42 age, sex, and body mass index (BMI)-matched controls were included in the study. Visfatin levels, FMD, and cIMT were measured using appropriate methods.

Results

Visfatin levels of the patients were significantly higher than controls (p < 0.001). FMD values in patients with AS were significantly lower (p = 0.007) whereas cIMT were significantly higher than the controls (p = 0.003). There was a negative relationship between FMD with visfatin levels (p = 0.004), BASDAI (p = 0.010), and BASFI (p = 0.007). There was a positive relationship between cIMT with visfatin (p = 0.005), BASDAI (p < 0.001), and BASFI (p < 0.001). There was a positive relationship between visfatin with BASDAI (p < 0.001), and BASFI (p < 0.001).

Conclusion

Visfatin levels are increased and associated with impaired FMD and increased cIMT in patients with AS. Increased visfatin levels may be associated with subclinical atherosclerosis in AS.

Adipokines and Arterial Stiffness in Obesity

Adipokines are active molecules with pleiotropic effects produced by adipose tissue and involved in obesity-related metabolic and cardiovascular diseases. Arterial stiffness, which is a consequence of arteriosclerosis, has been shown to be an independent predictor of cardiovascular morbidity and mortality. The pathogenesis of arterial stiffness is complex but incompletely understood. Adipokines dysregulation may induce, by various mechanisms, vascular inflammation, endothelial dysfunction, and vascular remodeling, leading to increased arterial stiffness. This article summarizes literature data regarding adipokine-related pathogenetic mechanisms involved in the development of arterial stiffness, particularly in obesity, as well as the results of clinical and epidemiological studies which investigated the relationship between adipokines and arterial stiffness.

Inflammatory Gene Expression in Neck Perivascular and Subcutaneous Adipose Tissue in Men With Carotid Stenosis

The inflammatory phenotype of neck adipose tissue (NAT) might reflect its involvement in the pathogenesis of carotid atherosclerosis. We investigated inflammatory gene expression in the subcutaneous and the perivascular (pericarotid) adipose tissue from patients with carotid stenosis (CS) undergoing endarterectomy and a control group of patients without significant carotid atherosclerosis undergoing thyroid surgery. Only male patients were included (n = 13 in each study group). Clinical and biochemical data along with serum leptin, adiponectin, and monocyte chemoattractant protein 1 (MCP-1) were collected. Adipose tissue samples were obtained from both the subcutaneous and pericarotid compartments. Real-time polymerase chain reaction was used to measure gene expression of macrophage markers and adipokines. The CS group had higher subcutaneous and pericarotid visfatin gene expression and higher pericarotid expression of MCP-1 and CD68 genes. The ratio between pericarotid CD206 and CD68 gene expression was similar between study groups. Adiponectin gene expression in both NAT compartments did not differ between groups, but it was negatively associated with body weight. These observations suggest that NAT, and especially the pericarotid compartment, express enhanced inflammatory properties in patients with CS, but the proportion of anti-inflammatory macrophages in advanced atherosclerosis seems to be maintained.

The effects of physical activity on adipokines in individuals with overweight/obesity across the lifespan: A narrative review

This narrative review summarizes current knowledge on the effects of physical activity (PA) on adipokine levels in individuals with overweight and obesity. Approximately 90 investigations including randomized control, cross-sectional and longitudinal studies that reported on the effects of a single session of PA (acute) or long-term PA (chronic) on adipokine levels in individuals with overweight/obesity were reviewed. The findings support the notion that there is consensus on the benefits of chronic exercise training-regardless of the mode (resistance vs. aerobic), intensity and cohort (healthy vs. diabetes)-on adipokine levels (such as tumour necrosis factor-alpha, interleukin-6, adiponectin, visfatin, omentin-1 and leptin). However, several confounding factors (frequency, intensity, time and type of exercise) can alter the magnitude of the effects of an acute exercise session. Available evidence suggests that PA, as a part of routine lifestyle behaviour, improves obesity complications by modulating adipokine levels. However, additional research is needed to help identify the most effective interventions to elicit the most beneficial changes in adipokine levels in individuals with overweight/obesity.

The Role of microRNAs in Metabolic Syndrome-Related Oxidative Stress

Oxidative stress (OxS) is the cause and the consequence of metabolic syndrome (MetS), the incidence and economic burden of which is increasing each year. OxS triggers the dysregulation of signaling pathways associated with metabolism and epigenetics, including microRNAs, which are biomarkers of metabolic disorders. In this review, we aimed to summarize the current knowledge regarding the interplay between microRNAs and OxS in MetS and its components. We searched PubMed and Google Scholar to summarize the most relevant studies. Collected data suggested that different sources of OxS (e.g., hyperglycemia, insulin resistance (IR), hyperlipidemia, obesity, proinflammatory cytokines) change the expression of numerous microRNAs in organs involved in the regulation of glucose and lipid metabolism and endothelium. Dysregulated microRNAs either directly or indirectly affect the expression and/or activity of molecules of antioxidative signaling pathways (SIRT1, FOXOs, Keap1/Nrf2) along with effector enzymes (e.g., GPx-1, SOD1/2, HO-1), ROS producers (e.g., NOX4/5), as well as genes of numerous signaling pathways connected with inflammation, insulin sensitivity, and lipid metabolism, thus promoting the progression of metabolic imbalance. MicroRNAs appear to be important epigenetic modifiers in managing the delicate redox balance, mediating either pro- or antioxidant biological impacts. Summarizing, microRNAs may be promising therapeutic targets in ameliorating the repercussions of OxS in MetS.

The up-regulation of markers of adipose tissue fibrosis by visfatin in pre-adipocytes as well as obese children and adolescents

Adipocytes are surrounded by a three-dimensional network of extracellular matrix (ECM) proteins. Aberrant ECM accumulation and remodeling leads to adipose tissue fibrosis. Visfatin is one of the adipocytokines that is increased in obesity and is implicated in insulin resistance. The objective of this study was to investigate the effect of visfatin on major components of ECM remodeling. In this study, plasma levels of both endotrophin and visfatin in obese children and adolescents were significantly higher than those in control subjects and they showed a positive correlation with each other. Treatment of 3T3-L1 pre-adipocytes with visfatin caused significant up-regulation of Osteopontin (Opn), Collagen type VI (Col6), matrix metalloproteinases MMP-2 and MMP-9. By using inhibitors of major signaling pathways it was shown that visfatin exerted its effect on Col6a3 gene expression through PI3K, JNK, and NF-кB pathways, while induced Opn gene expression via PI3K, JNK, MAPK/ERK, and NOTCH1. Our conclusion is that, the relationship between visfatin, endotrophin and insulin resistance parameters in obesity as well as increased expression of ECM proteins by visfatin suggests adipose tissue fibrosis as a mechanism for devastating effects of visfatin in obesity.

Association between circulating visfatin and pre-eclampsia: a systematic review and meta-analysis

OBJECTIVE

Pre-eclampsia (PE) is a serious pregnancy status characterized by high blood pressure. Although visfatin is usually associated with PE. Observational studies evaluating the relationship between circulating visfatin and pre-eclampsia have reported inconsistent results. We conducted this systematic review and meta-analysis to summarize published data on the association between visfatin and pre-eclampsia.

METHODS

Electronic databases PubMed, ISI web of science, EMBASE, Scopus and the Cochrane library were comprehensively searched for selection of eligible studies until January 5, 2020. A random-effects model and the generic inverse variance method were used for quantitative data synthesis. The assessment of study quality was performed using the e Newcastle-Ottawa scale and the Agency for Healthcare Research and Quality. Sensitivity analyses and prespecified subgroup were conducted to evaluate potential heterogeneity. Random-effects meta-regression was conducted to assess the impact of potential confounders on the estimated effect sizes. The protocol for this study was registered in PROSPERO (No. CRD42018105861) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Thirteen studies comprising a total of 536 subjects were included in this meta-analysis. We observed that the pre-eclampsia risk is associated with a statistically significant elevation of visfatin level [SMD (1.33 µg/l) (95% CI 0.37, 2.2) p = .007]. No significant publication bias was observed in the meta-analysis. Subgroup and sensitivity analyses indicated that the pooled effects size were affected by systolic blood pressure [SMD (1.82 µg/l) 95% CI (0.94, 2.7), p < .05], gestational age [SMD (2.01 µg/l) 95% CI (0.57, 3.4), p = .006], body mass index [SMD (1.6 µg/l) 95% CI (0.37, 3), p < .05] and pregnancy trimesters[SMD (2.3 µg/l) 95% CI (0.95, 3.7), p = .001]. Random-effects meta-regression showed a significant association of visfatin level with potential confounders including systolic blood pressure, gestational age and birth weight at delivery of pre-eclampsia patients.

CONCLUSIONS

Collectively, our data revealed that the increase of visfatin level can be associated with the risk of pre-eclampsia. However, further studies on pre-eclampsia populations are warranted for corroboration of our findings.

Study of visfatin expression in acne patients in tissue and serum

Background

Acne is a chronic inflammatory disease of the pilosebaceous units, of multifactorial pathogenesis, one of which could be an adipokine such as visfatin.

Aim

The aim of this study was to study visfatin expression both in lesional skin and serum, of acne patients versus healthy controls. The secondary aim was to study the relationship of visfatin levels with dyslipidemia/metabolic syndrome.

Methods

This study included 30 patients with moderate and severe acne vulgaris and 30 age- and sex-matched healthy controls. Serum and tissue visfatin were estimated by enzyme-linked immune-sorbent assay. Clinical and laboratory examinations were done to assess the anthropometric data and various criteria of metabolic syndrome.

Results

Tissue and serum visfatin levels were significantly higher in patients as compared to healthy controls. Tissue visfatin levels were significantly higher than its serum levels in both patients and controls. Serum visfatin was significantly higher in overweight individuals. No correlations were found between tissue and serum visfatin levels in both patients and controls. Moreover, serum and tissue visfatin levels did not correlate to any of the lipid profile parameters or criteria of metabolic syndrome in acne patients.

Limitations

The study had a small sample size and did not localize the exact source of tissue visfatin. Polycystic ovary syndrome PCOS was not evaluated.

Conclusion

Visfatin is an important proinflammatory adipokine, with significantly higher expression in acne patients. Tissue rather than serum visfatin might play a key role in acne.

Nicotinamide phosphoribosyltransferase aggravates inflammation and promotes atherosclerosis in ApoE knockout mice

Nicotinamide phosphoribosyltransferase (Nampt) is the rate-limiting enzyme of nicotinamide adenine dinucleotide (NAD) salvage biosynthesis in mammals, and is involved in fundamental physiological processes and pathophysiology of many diseases. Thus far, however, the role of Nampt in atherosclerosis development is still in debate. In this study, we crossed global Nampt transgenic mice (Nampt-Tg) with a well-established atherosclerosis animal model (ApoE knockout mice, ApoE^-/-) to generate ApoE^-/-;Nampt-Tg mice and investigated the effects of Nampt overexpression on atherosclerosis development in ApoE^-/- mice. Both ApoE^-/- and ApoE^-/-;Nampt-Tg mice were fed with a pro-atherosclerotic high-fat diet (HFD) for 16 weeks. Their serum lipid contents and atherosclerotic lesion were assessed. The results showed that there was no significant difference in body weight or serum levels of glucose, total cholesterol, triglycerides, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol between the two strains of mice, but ApoE^-/-;Nampt-Tg mice had a significantly higher level of serum non-esterified fatty acid. Compared with ApoE^-/- mice, ApoE^-/-;Nampt-Tg mice displayed significantly increased atherosclerotic lesion area and thickness, lower collagen content, decreased collagen I/III ratio (collagen immaturation), increased number of apoptotic cells, and enhanced activities of caspase-3, caspase-8, and caspase-9. Moreover, macrophage infiltration (F4/80 staining), tumor necrosis factor signaling, and chemokines expression (ICAM-1 and CXCR-4) were all activated in aortic atherosclerotic plaque of ApoE^-/-;Nampt-Tg mice compared with ApoE^-/- mice. Our results provide in vivo evidence that Nampt transgene aggravates atherosclerotic inflammation and promotes atherosclerosis development in ApoE^-/- mice.

Circulating visfatin levels in the second and third trimester of pregnancies with gestational diabetes: a systematic review

INTRODUCTION

There are multiple published conflicting associations of the adipocytokine visfatin with gestational diabetes. In this study, we attempted to investigate this relationship via a systematic review of the published literature.

EVIDENCE ACQUISITION

Literature retrieval using PubMed, Google Scholar, Scopus and Hydi databases followed by article selection and data extraction were conducted. Relevant studies published up to June 2018 were included. In total, 29 cohorts that were published in 27 articles were analyzed. Three studies carried out in early pregnancy were excluded. A total of 2365 individuals, with 1069 gestational diabetes (GDM) cases and 1296 controls from studies describing visfatin in the second or third trimester of gestation were included.

EVIDENCE SYNTHESIS

The difference in visfatin levels between women with GDM and the controls in the second and third trimester was measured by weighted mean difference (WMD) and 95% confidence intervals (CI). Heterogeneity was inspected by using both subgroup and meta-regression analysis. Analysis was restricted to studies describing singleton pregnancies. The quality of included studies was assessed by the Newcastle-Ottawa Scale.

CONCLUSIONS

No significant difference in circulating visfatin levels in GDM during the second trimester of pregnancy (WMD -0.30 ng/mL, 95% CI: -2.06, 1.45, SE=0.895, P=0.733) was detected. Meta-analysis of the studies in the third trimester revealed a significant negative effect, that was however driven by only one study. This finding limits the meaningful interpretation of the pooled analysis. Significant heterogeneity was identified between studies, and meta-regression analysis showed that homeostatic model assessment for insulin resistance contributes significantly to heterogeneity. In conclusion, our findings suggest that peripheral blood visfatin concentration cannot be robustly associated with gestational diabetes status in the second and third trimesters of pregnancy.

Association between serum visfatin levels and atherosclerotic plaque in patients with type 2 diabetes

BACKGROUND

Visfatin is a multifaceted protein that plays an important role in regulating a variety of physiological and pathological processes, including obesity, diabetes and cardiovascular disease. However, circulating visfatin levels in atherosclerosis plaque progression in patients with type 2 diabetes, or its association with the vascular territory affected remain unclear.

METHODS

We evaluated the relationship between visfatin levels and carotid or femoral artery atherosclerosis in Chinese patients with type 2 diabetes. Serum levels of visfatin were measured by enzyme-linked immunosorbent assay (ELISA) in 97 inpatients with type 2 diabetes. Carotid and/or femoral atherosclerotic plaques were detected by B-mode ultrasound.

RESULTS

Serum visfatin levels were elevated in the group with atherosclerotic plaques compared to the control group without plaques [0.68 (0.46-1.58) versus 0.45 (0.23-0.76) ng/mL, respectively, P = 0.0002]. Patients with carotid plaques showed higher visfatin levels than those with or without femoral plaques. Pearson's correlation analysis showed that serum visfatin levels were positively correlated with waist circumference (r = 0.226, P = 0.029), waist-hip ratio (r = 0.221, P = 0.032), TG (r = 0.222, P = 0.030) and number of plaques (r = 0.275, P = 0.009). Logistic regression analysis showed that a higher serum visfatin level was an independent predictor for the presence of atherosclerotic plaques.

CONCLUSIONS

In conclusion, among patients with T2DM, serum visfatin levels were elevated in those with atherosclerotic plaques, especially in patients with carotid atherosclerotic plaques. Serum visfatin may serve as a predictor of atherosclerotic plaques in patients with T2DM.

Chronic intermittent hypobaric hypoxia protects vascular endothelium by ameliorating autophagy in metabolic syndrome rats

AIMS

The study aimed to investigate the protective effect of chronic intermittent hypobaric hypoxia (CIHH) on endothelium function and relaxation of mesenteric artery in metabolism syndrome (MS) rats.

MAIN METHODS

Male adult Sprague-Dawley rats were randomly divided into control (CON), CIHH (treated with 28-days hypobaric hypoxia simulating an altitude of 5000 m, 6 h daily), MS (induced by high fat diet and 10% fructose water feeding), and MS + CIHH groups. Body weight, systolic arterial pressure, blood biochemical and the endothelium dependent relaxation (EDR) of mesenteric arteries were measured. The expression of phosphor-endothelial nitric oxide synthase (p-eNOS), endoplasmic reticulum (ER) stress-related proteins and autophagy-related proteins in mesenteric arteries was assayed.

KEY FINDINGS

The MS rats displayed hypertension, obesity, metabolic abnormity and insulin resistance, EDR was attenuated, p-eNOS expression was down-regulated, the expressions of ER stress-related proteins were up-regulated, and autophagy dysfunction occurred. All aforementioned abnormalities in MS rats were ameliorated in MS + CIHH rats. Furthermore, the improvement of CIHH on EDR and p-eNOS was cancelled by the ER stress inducer, and the autophagy inhibitor.

SIGNIFICANCE

In conclusion CIHH protects endothelium function and enhances relaxation in mesenteric arteries of MS rats through improving autophagy function, reducing ER stress and up-regulating p-eNOS.

Suppressive effects of berberine on atherosclerosis via downregulating visfatin expression and attenuating visfatin-induced endothelial dysfunction

Berberine (BBR) possesses significant anti-atherosclerosis properties. Visfatin is one of the most promising biomarkers of incoming atherosclerosis. However, research on the effect of BBR on regulating visfatin expression in atherogenesis remains largely unknown. In this study, we investigated the effects of BBR on visfatin expression and atherogenesis in apolipoprotein E knockout (ApoE-/-) mice. The effect of BBR on attenuating visfatin-induced endothelial dysfunction was also evaluated in cultured human umbilical vein endothelial cells (HUVECs). In vivo experiments showed that BBR treatment (5 mg/kg/day) significantly reduced the serum levels of visfatin, lipid, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), the protein expression of visfatin, p-p38 MAPK and p-c-Jun N-terminal kinase (JNK) in mice aorta and the distribution of visfatin in the atherosclerotic lesions in ApoE-/- mice fed with a Western diet. In addition, in vitro experiments indicated that visfatin (100 µg/l) significantly increased apoptosis, the contents of IL-6 and TNF-α, the protein levels of p-p38 MAPK, p-JNK and Bax in HUVECs, which were reversed by BBR administration (50 µmol/l). Our findings suggest that BBR significantly ameliorates Western diet-induced atherosclerosis in ApoE-/- mice via downregulating visfatin expression, which is related to the inhibition of p38 MAPK and JNK signaling pathways and subsequent suppression of visfatin-induced endothelial dysfunction.

Visfatin levels are increased in patients with resistant hypertension and are correlated with left ventricular hypertrophy

OBJECTIVE

The aim of this study was to investigate the possible correlation of serum visfatin levels with resistant hypertension (RHT).

PATIENTS AND METHODS

Patients who had undergone ambulatory blood pressure measurements (ABPM) during the outpatient controls were prospectively recruited. Seventy-one patients with RHT and 94 patients with controlled hypertension (CHT) were included in the study. RHT was defined as 'uncontrolled blood pressure (BP) despite using three antihypertensive agents including a diuretic or need of four or more drugs to control BP'. The demographic properties, medications used, and laboratory parameters including visfatin levels were recorded.

RESULTS

In the RHT group, left ventricular mass index was significantly higher compared with the CHT group (108.13±26.86 vs. 89.46±24.09 g/m, P<0.01). High-sensitivity C-reactive protein and visfatin levels were significantly higher in the RHT group [4.0 (5.2) vs. 2.3 (3.0) mg/l, P<0.01, and 12.87±4.98 vs. 9.46±4.69 ng/ml, P<0.01, respectively] compared with the CHT group. In the multivariate linear regression model, visfatin level remained as an independent predictor for office systolic BP [B: 2.07, 95% confidence interval (CI): 1.17-2.98, P<0.01]; office diastolic BP (B: 0.71, 95% CI: 0.27-1.16, P<0.01); mean 24-h systolic ABPM (B: 1.46, 95% CI: 0.79-2.13, P<0.01); and mean 24-h diastolic ABPM (B: 0.88, 95% CI: 0.42-1.34, P<0.01) and was also correlated independently with left ventricular mass index (B: 3.13, 95% CI: 2.58-3.99, P<0.01).

CONCLUSION

In this cohort of RHT patients diagnosed with ABPM, we have found an independent correlation between higher visfatin levels and the presence of RHT and left ventricular hypertrophy.

Nicotinamide Phosphoribosyltransferase Promotes Pulmonary Vascular Remodeling and Is a Therapeutic Target in Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension is a severe and progressive disease, a hallmark of which is pulmonary vascular remodeling. Nicotinamide phosphoribosyltransferase (NAMPT) is a cytozyme that regulates intracellular nicotinamide adenine dinucleotide levels and cellular redox state, regulates histone deacetylases, promotes cell proliferation, and inhibits apoptosis. We hypothesized that NAMPT promotes pulmonary vascular remodeling and that inhibition of NAMPT could attenuate pulmonary hypertension.

METHODS

Plasma, mRNA, and protein levels of NAMPT were measured in the lungs and isolated pulmonary artery endothelial cells from patients with pulmonary arterial hypertension and in the lungs of rodent models of pulmonary hypertension. Nampt^+/- mice were exposed to 10% hypoxia and room air for 4 weeks, and the preventive and therapeutic effects of NAMPT inhibition were tested in the monocrotaline and Sugen hypoxia models of pulmonary hypertension. The effects of NAMPT activity on proliferation, migration, apoptosis, and calcium signaling were tested in human pulmonary artery smooth muscle cells.

RESULTS

Plasma and mRNA and protein levels of NAMPT were increased in the lungs and isolated pulmonary artery endothelial cells from patients with pulmonary arterial hypertension, as well as in lungs of rodent models of pulmonary hypertension. Nampt^+/- mice were protected from hypoxia-mediated pulmonary hypertension. NAMPT activity promoted human pulmonary artery smooth muscle cell proliferation via a paracrine effect. In addition, recombinant NAMPT stimulated human pulmonary artery smooth muscle cell proliferation via enhancement of store-operated calcium entry by enhancing expression of Orai2 and STIM2. Last, inhibition of NAMPT activity attenuated monocrotaline and Sugen hypoxia-induced pulmonary hypertension in rats.

CONCLUSIONS

Our data provide evidence that NAMPT plays a role in pulmonary vascular remodeling and that its inhibition could be a potential therapeutic target for pulmonary arterial hypertension.

The relationship between visfatin and serum concentrations of C-reactive protein, interleukin 6 in patients with metabolic syndrome

AIM

To evaluate the relationship between inflammatory and pro inflammatory markers, with obesity and visceral adiposity in male subjects with or without metabolic syndrome (MS).

SUBJECTS AND METHODS

A total of 37 patients with MS and 37 age matched controls were included (mean age 46.35 ± 1.6 years). MS was defined by the criteria of the international diabetes federation 2005. Anthropometric and biochemical profiles, including high-sensitivity C-reactive protein (Hs-CRP), visfatin and interleukin 6 (IL-6), were measured. Data were compared between groups by using t test. Pearson's correlation was used to evaluate the relationship between variables. P values less than 0.05 were considered as statistically significant.

RESULTS

In patients with MS, CRP and IL-6 were significantly correlated with body mass index, waist circumference and waist to hip ratio. Visfatin levels were significantly lower in patients with MS compared to controls (log visfatin: 1.74 ± 0.27 vs. 1.86 ± 0.13 ng/ml, MS vs. control group respectively). We cannot find any significant correlation between visfatin, CRP and IL-6. Also there were no correlation between visfatin levels and any anthropometric parameters in patients with MS or control groups.

CONCLUSION

Serum visfatin was lower in patients with MS. Therefore it seems that visfatin could not be considered as a pro inflammatory adipocytokine in MS. The positive associations of obesity and visceral adiposity with elevated CRP and IL-6 levels suggest the importance of reducing visceral adiposity to prevent the risk of coronary disease.

Expression of visfatin in the diabetic rat retina

BACKGROUND

Visfatin has been found in adipose tissue, liver and kidney of healthy and diabetic people, with its expression being increased in the aforementioned tissues in diabetes. Based on the former researches, visfatin may exist in the retina and affect the development of diabetic retinopathy. The expression of visfatin in Sprague-Dawley rats' retina, which may carve a path to study the pathogenesis of diabetic retinopathy, was investigated by this study.

METHODS

The mRNA and protein expression of visfatin in Sprague-Dawley rats' retina were detected by the reverse transcription-polymerase chain reaction (RT-PCR) and western blot. Immunohistochemical staining was applied to detect the expression location of visfatin in the rats' retinas.

RESULTS

The mRNA and visfatin protein expressions in both normal and streptozocin-induced diabetic rats' retina increased significantly in 2 to 8 weeks of diabetes mellitus (DM). Compared with the normal control groups, the difference was statistically significant (P < 0.05). The histological examination showed that the retinal thickness decreased gradually over the course of DM and the decrease in the outer nuclear layer was the most obvious. At 4 and 8 weeks, the decrease in the retinal thickness was significant (P < 0.01). Visfatin was expressed in the retinal nerve fibre layer, inner plexiform layer and outer plexiform layer, and with the progression of DM, its expression was increased.

CONCLUSIONS

Visfatin was expressed in the rats' retinas, mainly in the retinal nerve fibre layer, inner plexiform layer and outer plexiform layer. As the development of DM course, its expression was gradually increased.

Increased serum visfatin as a risk factor for atherosclerosis in patients with ischaemic cerebrovascular disease

INTRODUCTION

The present study aimed to investigate the possible associations between serum levels of visfatin, an adipokine, and atherosclerosis in patients with ischaemic cerebrovascular disease.

METHODS

A total of 95 participants were recruited for this study. Group A comprised 35 individuals with no history of cerebrovascular disease (control group) and Group B comprised 60 patients with ischaemic cerebrovascular disease. Group B was further categorised into two subgroups based on the ultrasonographic findings of the common carotid artery intima‑media thickness (CCA‑IMT) - Group B1 consisted of 21 patients with no atherosclerosis (i.e. CCA‑IMT ≤ 0.9 mm) and Group B2 consisted of 39 patients with atherosclerosis (i.e. CCA‑IMT > 0.9 mm). The body mass index, fasting blood total cholesterol, triglycerides, high‑density lipoprotein cholesterol, low‑density lipoprotein cholesterol and glucose levels of each patient were measured. Serum visfatin levels were determined using enzyme‑linked immunosorbent assays. Visfatin levels were compared between groups, and stepwise logistic regression analysis was used to identify risk factors for atherosclerosis, including visfatin levels.

RESULTS

The mean serum visfatin level of the patients in Group B was higher than that in Group A (75.5 ± 77.80 ng/mL vs. 8.6 ± 4.69 ng/mL; p < 0.05) and the level was higher in patients from Group B2 than those from Group B1 (89.0 ± 80.68 ng/mL vs. 50.4 ± 72.44 ng/mL; p < 0.05). Multivariate regression analysis showed that CCA‑IMT values were not significantly associated with visfatin levels. However, logistic regression analysis showed that serum visfatin was an independent risk factor for atherosclerosis (odds ratio 37.80; p = 0.004).

CONCLUSION

Serum visfatin may be an independent risk factor for cerebral infarction, as high serum visfatin levels are positively associated with the underlying pathogenic mechanisms of ischaemic cerebrovascular disease.

Mechanisms of enhanced insulin secretion and sensitivity with n-3 unsaturated fatty acids

The widespread acceptance that increased dietary n-3 polyunsaturated fatty acids (PUFAs), especially α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), improve health is based on extensive studies in animals, isolated cells and humans. Visceral adiposity is part of the metabolic syndrome, together with insulin resistance, dyslipidemia, hypertension and inflammation. Alleviation of metabolic syndrome requires normalization of insulin release and responses. This review assesses our current knowledge of the mechanisms that allow n-3 PUFAs to improve insulin secretion and sensitivity. EPA has been more extensively studied than either ALA or DHA. The complex actions of EPA include increased G-protein-receptor-mediated release of glucagon-like peptide 1 (GLP-1) from enteroendocrine L-cells in the intestine, up-regulation of the apelin pathway and down-regulation of other control pathways to promote insulin secretion by the pancreatic β-cells, together with suppression of inflammatory responses to adipokines, inhibition of peroxisome proliferator-activated receptor α actions and prevention of decreased insulin-like growth factor-1 secretion to improve peripheral insulin responses. The receptors involved and the mechanisms of action probably differ for ALA and DHA, with antiobesity effects predominating for ALA and anti-inflammatory effects for DHA. Modifying both GLP-1 release and the actions of adipokines by n-3 PUFAs could lead to additive improvements in both insulin secretion and sensitivity.

Adipokines, Vascular Wall, and Cardiovascular Disease

Epidemiological evidence has shown that abdominal obesity is closely associated with the development of cardiovascular (CV) disease, suggesting that it might be considered as an independent CV risk factor. However, the pathophysiological mechanisms responsible for the association between these 2 clinical entities remain largely unknown. Adipocytes are considered able to produce and secrete chemical mediators known as “adipokines” that may exert several biological actions, including those on heart and vessels. Of interest, a different adipokine profile can be observed in the plasma of patients with obesity or metabolic syndrome compared with healthy controls. We consider the main adipokines, focusing on their effects on the vascular wall and analyzing their role in CV pathophysiology.

Beijing ambient particle exposure accelerates atherosclerosis in ApoE knockout mice by upregulating visfatin expression

Ambient particulate matter (PM) exposure has been associated with atherosclerosis. However, research on the effect of real-world exposure to ambient PM in regulating visfatin expression in an animal model is very limited. The objective is to investigate whether Beijing ambient PM exposure could accelerate atherosclerosis in ApoE knockout (ApoE(-/-)) mice by upregulating visfatin expression. Forty male ApoE(-/-) mice were exposed to untreated ambient air (PM group, n = 20) or filtered air (FA group, n = 20), 24 h/day, 7 days/week, for 2 months. During the exposure, the mass concentrations of PM2.5 and PM10 in the two groups were continuously monitored. Moreover, a receptor source apportionment model was applied to apportion sources of PM2.5. At the end of the exposure, visfatin in plasma and aorta, biomarkers of inflammation, oxidative stress and lipid metabolism in blood samples, and bronchoalveolar lavage fluid (BALF) were determined, and the plaque area of the atherosclerosis lesions was quantified. PM-exposed mice were significantly higher than FA-exposed mice in terms of plasma visfatin, OxLDL, MDA, serum TC, LDL, TNF-α as well as IL-6, TNF-α, OxLDL, and MDA in BALF, while SOD and GSH-Px activities in plasma and BALF were reduced in PM-exposed mice. Pathological analysis of the aorta demonstrated that the plaque area and visfatin protein in the PM group increased significantly compared to the FA group. Our findings indicate that ambient PM exposure could accelerate atherosclerosis, which is related to visfatin upregulation, as well as the activation of inflammation and oxidative stress.

Endothelial NLRP3 inflammasome activation and enhanced neointima formation in mice by adipokine visfatin

Inflammasomes serve as an intracellular machinery to initiate inflammatory response to various danger signals. The present study tested whether an inflammasome centered on nucleotide oligomerization domain-like receptor protein 3 (NLRP3) triggers endothelial inflammatory response to adipokine visfatin, a major injurious adipokine during obesity. NLRP3 inflammasome components were abundantly expressed in cultured mouse microvascular endothelial cells, including NLRP3, apoptosis-associated speck-like protein, and caspase-1. These NLRP3 inflammasome molecules could be aggregated to form an inflammasome complex on stimulation of visfatin, as shown by fluorescence confocal microscopy and size exclusion chromatography. Correspondingly, visfatin significantly increased caspase-1 activity and IL-1β release in microvascular endothelial cells, indicating an activation of NLRP3 inflammasomes. In animal experiments, direct infusion of visfatin in mice with partially ligated left carotid artery were found to have significantly increased neointimal formation, which was correlated with increased NLRP3 inflammasome formation and IL-1β production in the intima. Further, visfatin-induced neointimal formation, endothelial inflammasome formation, and IL-1β production in mouse partially ligated left carotid artery were abolished by caspase-1 inhibition, local delivery of apoptosis-associated speck-like protein shRNA or deletion of the ASC gene. In conclusion, the formation and activation of NLRP3 inflammasomes by adipokine visfatin may be an important initiating mechanism to turn on the endothelial inflammatory response leading to arterial inflammation and endothelial dysfunction in mice during early stage obesity.

Biomarkers in the field of obesity and its related comorbidities

INTRODUCTION

The prevalence of obesity has increased dramatically in the last decades both in children and adults and is now considered a major health problem. It is associated with numerous comorbidities such as hypertension, dyslipidemia, diabetes and subsequent cardiovascular disease (CVD). One of the mechanisms that connect obesity with these comorbidities is the secretion of so-called adipocytokines or adipokines by the adipose tissue itself. Most adipokines with pro-inflammatory properties are overproduced with increasing adiposity, whereas some adipokines with anti-inflammatory or insulin-sensitizing properties, like adiponectin, are decreased. This dysregulation of adipokines production may promote obesity-linked metabolic disorders and CVD. Except adipokines a wide complex network of chemicals balances pro-inflammatory and anti-inflammatory effects.

AREAS COVERED

In this review, we summarize the role of various adipokines and other chemicals associated with obesity and its related cardiometabolic comorbidities, with a special focus on recent evidence showing their potential role as biomarkers whose expression are indicative of obesity and its complications.

EXPERT OPINION

Biomarkers associated with obesity, type 2 diabetes (T2D) and CVD could prove beneficial for early identification, proper treatment and good life assurance. Unfortunately, the complexity of biological pathways interactions is such that further research is necessary before any of these markers could reach an accurate diagnostic value.

Visfatin contributes to the differentiation of monocytes into macrophages through the differential regulation of inflammatory cytokines in THP-1 cells

Visfatin is a novel multifunctional adipocytokine with inflammatory properties. Although a link between visfatin and atherosclerosis has recently been suggested, its actions in the development of atherosclerosis remain unknown. Therefore, we investigated a potential role and underlying mechanism(s) of visfatin in monocytes/macrophages differentiation, a critical early step in atherogenesis, using phorbol-12-myristate-13-acetate (PMA)-stimulated THP-1 cell models. The co-incubation of PMA with visfatin-induced CD36 expression with a concomitant increase in the phagocytosis of latex beads compared with PMA alone treatment. Moreover, visfatin markedly increased interleukin (IL)-1β secretion by enhancing IL-1β mRNA stability in a short-term incubation. Visfatin also significantly elevated the secretion of IL-6 as well as IL-1β in a longer incubation period, which was partially suppressed by nuclear factor-κB (NF-κB) inhibitor, BAY11-7082, and c-Jun-N-terminal kinase (JNK) inhibitor, SP600125. Furthermore, silencing IL-1β successfully blocked IL-6 secretion, CD36 expression, and NF-κB activation in response to visfatin. Collectively, these results suggest that visfatin enhances the IL-1β-dependent induction of IL-6 and CD36 via distinct signaling pathways mediated by JNK and NF-κB, respectively, and consequently, leading to the acceleration of monocytes/macrophages differentiation.

Differential significance of plasma visfatin concentrations according to adiposity in children and adolescents

BACKGROUND/AIMS

Visfatin is an adipocytokine predominantly expressed in visceral adipose tissue. We examined the relationship between plasma visfatin concentrations and anthropometric and metabolic parameters in children and adolescents, who are relatively less influenced by the effects of accompanying disease.

METHODS

We studied 135 children and adolescents (8-16 years old). Plasma glucose, insulin, lipid profile, visfatin and other adipocytokine levels were measured. CT scans were performed to evaluate the distribution of abdominal fat. We analyzed the relationship between circulating visfatin levels and anthropometric and metabolic parameters according to central adiposity (total abdominal fat by CT scan).

RESULTS

In the lower-adiposity group, plasma visfatin concentrations were significantly correlated with total abdominal fat, visceral fat, subcutaneous abdominal fat, plasma triglyceride level and homeostasis model assessment of insulin resistance (HOMA-IR). In a multiple linear regression analysis, visceral fat and triglycerides were independently associated with plasma visfatin levels. In the higher-adiposity group, plasma visfatin concentrations were not correlated with visceral fat or HOMA-IR but were significantly correlated with circulating interleukin-6 levels.

CONCLUSION

These data suggest that the relationship between plasma visfatin concentrations and metabolic parameters differs according to central adiposity and that plasma visfatin concentrations are correlated with visceral fat and triglyceride levels, especially in children and adolescents with lower adiposity.

The effects of NAMPT haplotypes and metabolic risk factors on circulating visfatin/NAMPT levels in childhood obesity

OBJECTIVE

Polymorphisms in the NAMPT gene, which encodes the adipocytokine visfatin/nicotinamide phosphorybosil transferase (NAMPT), affect the circulating visfatin/NAMPT levels and are associated with obesity and cardiovascular diseases. However, no study has tested the hypothesis that NAMPT haplotypes could affect visfatin/NAMPT levels in case of childhood obesity. We investigated the effects of traditional metabolic risk factors (MRFs) and NAMPT polymorphisms T/C (rs1319501) and A/G (rs3801266) or haplotypes on visfatin/NAMPT levels in obese children and adolescents, and whether NAMPT polymorphisms and/or haplotypes are associated with susceptibility to childhood obesity.

METHODS

We studied 175 control, 99 obese and 82 obese with ⩾ 3 MRFs children and adolescents. Genotypes were determined by a Taqman allele discrimination assay and real-time PCR. The plasma visfatin/NAMPT level was measured using an enzyme immunoassay.

RESULTS

Obese children and adolescents with ⩾ 3 MRFs had higher plasma visfatin/NAMPT levels in comparison with control children and adolescents (P<0.05). Although positive associations were observed between visfatin/NAMPT and body mass index (rs = 0.157; P = 0.034) as well as visfatin/NAMPT and waist circumference (rs = 0.192; P = 0.011), visfatin/NAMPT and high-density lipoprotein cholesterol were inversely associated (rs = -0.162; P = 0.031). No significant differences in genotype, allele or haplotype frequency distributions for the studied polymorphisms were found when the three groups were compared. However, higher plasma visfatin/NAMPT levels were found in control and obese subjects carrying the GG genotype for the A/G (rs3801266) polymorphism (P<0.05) but not in obese children with ⩾ 3 MRFs. Moreover, control subjects carrying the 'T-G' haplotype showed higher plasma visfatin/NAMPT levels. NAMPT genotypes or haplotypes were not associated with childhood obesity.

CONCLUSIONS

Obesity in children with ⩾ 3 MRFs increases plasma visfatin/NAMPT levels, and this marker was associated with body mass index and waist circumference. The A/G polymorphism and NAMPT haplotypes affect plasma visfatin/NAMPT levels in controls but not in obese children with ⩾ 3 MRFs. These results suggest that obesity and MRFs are more influential than genetic polymorphisms in the determination of visfatin/NAMPT levels in obese children. Further research is necessary to explain why the GG genotype is not associated with increased visfatin/NAMPT levels in obese children with ⩾ 3 MRFs.

Association of circulating levels of nicotinamide phosphoribosyltransferase (NAMPT/Visfatin) and of a frequent polymorphism in the promoter of the NAMPT gene with coronary artery disease in diabetic and non-diabetic subjects

Background

Nicotinamide phosphoribosyltransferase (NAMPT) is the limiting enzyme in one of pathways of synthesis of Nicotinamide Adenine Dinucleotide, a redox coenzyme. NAMPT is considered as an insulin-mimetic factor and a potential regulatory factor in inflammatory and immune processes. Associations of circulating NAMPT levels with cardiovascular disease (CVD) and insulin resistance have been reported. We investigated association of circulating NAMPT levels and the rs9770242 NAMPT gene polymorphism with coronary artery disease (CAD).

Methods

We studied 594 Brazilian subjects undergoing a coronary angiography (49% of whom had type 2 diabetes). CAD, defined as stenosis greater than 50% in one major coronary vessel or branch, was observed in 68% of subjects. Genetic studies were also performed in 858 North-American Non-Hispanic White subjects with type 2 diabetes (49% with CAD).

Results

We observed an interaction between glycemic and CAD status on the comparison of NAMPT levels by CAD status. NAMPT levels were higher in type 2 diabetic patients with CAD as compared to those without CAD: 5.27 ± 2.93 ng/ml vs. 4.43 ± 2.94 ng/ml, p = 0.006 (mean ± SD). NAMPT levels were not significantly different in non-diabetic subjects with or without CAD. The T-allele of rs9770242 was associated with CAD in the Brazilian cohort (OR 1.46, 95% CI 1.06 - 2.01, p = 0.02) while no association was observed in the North-American cohort.

Conclusions

Our data suggest that circulating NAMPT levels are associated with CAD in type 2 diabetic patients. NAMPT rs9770242 polymorphism may be associated with CAD in some populations.

Pre-B cell colony enhancing factor (PBEF), a cytokine with multiple physiological functions

Pre-B cell colony enhancing factor (PBEF) is regarded as a proinflammatory cytokine. Named for its first discovered function as a pre-B cell colony enhancing factor, it has since been found to have many other functions relating to cell metabolism, inflammation, and immune modulation. It has also been found to have intracellular and extracellular forms, with the two overlapping in function. Most of the intracellular functions of PBEF are due to its role as a nicotinamide phosphoribosyltransferase (Nampt). It has been found in human endothelial cells, where it is able to induce angiogenesis through upregulation of VEGF and VEGFR and secretion of MCP-1. In human umbilical endothelial cells, PBEF increases levels of the protease MMP 2/9. PBEF has also been found in a variety of immune cells other than B cells and has been shown to inhibit apoptosis of macrophages. Extracellular PBEF has been shown to increase inflammatory cytokines, such as TNF-α, IL-1β, IL-16, and TGF-β1, and the chemokine receptor CCR3. PBEF also increases the production of IL-6, TNF-α, and IL-1β in CD14(+) monocyctes, macrophages, and dendritic cells, enhances the effectiveness of T cells, and is vital to the development of both B and T lymphocytes. The purpose of this review is to summarize the recent advances in PBEF research.

Visfatin/Nampt: an adipokine with cardiovascular impact

Adipose tissue is acknowledged as an endocrine organ that releases bioactive factors termed adipokines. Visfatin was initially identified as a novel adipokine with insulin-mimetic properties in mice. This adipokine was identical to two previously described molecules, namely, pre-B cell colony-enhancing factor (PBEF) and the enzyme nicotinamide phosphoribosyltransferase (Nampt). Enhanced circulating visfatin/Nampt levels have been reported in metabolic diseases, such as obesity and type 2 diabetes. Moreover, visfatin/Nampt circulating levels correlate with markers of systemic inflammation. In cardiovascular diseases, visfatin/Nampt was initially proposed as a clinical marker of atherosclerosis, endothelial dysfunction, and vascular damage, with a potential prognostic value. Nevertheless, beyond being a surrogate clinical marker, visfatin/Nampt is an active player promoting vascular inflammation, and atherosclerosis. Visfatin/Nampt effects on cytokine and chemokine secretion, macrophage survival, leukocyte recruitment by endothelial cells, vascular smooth muscle inflammation and plaque destabilization make of this adipokine an active factor in the development and progression of atherosclerosis. Further research is required to fully understand the mechanisms mediating the cellular actions of this adipokine and to better characterize the factors regulating visfatin/Nampt expression and release in all these pathologic scenarios. Only then, we will be able to conclude whether visfatin/Nampt is a therapeutical target in cardiometabolic diseases.

Serum visfatin levels do not increase in post-menopausal women with metabolic syndrome

BACKGROUND

The aim of this study was to determine the serum visfatin levels in post-menopausal (PM) women with and without metabolic syndrome (MS) and to understand the correlation between serum visfatin levels and various other hormonal and metabolic parameters.

MATERIALS-METHODS

We conducted a prospective cross-sectional study including 17 PM women with MS and a control group of 51 PM women without MS. MS was defined according to the National Cholesterol Education Program Adult Treatment Panel III.

RESULTS

Women with MS had statistically significantly higher fasting blood glucose, HDL, triglycerides, insulin, homeostasis model assessment of insulin resistance, and SHBG levels when compared to women without MS. Estradiol, high sensitivity C-reactive protein, and free testosterone levels were higher in the MS group, but there was no statistically significant difference between the two groups. Visfatin levels did not differ between the two groups. There was no correlation between serum visfatin levels and other parameters.

CONCLUSIONS

There was no association between serum visfatin levels and MS in PM women.