Visfatin, low-grade inflammation and body mass index (BMI)

Novel targets for potential therapeutic use in Diabetes mellitus

Future targets are a promising prospect to overcome the limitation of conventional and current approaches by providing secure and effective treatment without compromising patient compliance. Diabetes mellitus is a fast-growing problem that has been raised worldwide, from 4% to 6.4% (around 285 million people) in past 30 years. This number may increase to 430 million people in the coming years if there is no better treatment or cure is available. Ageing, obesity and sedentary lifestyle are the key reasons for the worsening of this disease. It always had been a vital challenge, to explore new treatment which could safely and effectively manage diabetes mellitus without compromising patient compliance. Researchers are regularly trying to find out the permanent treatment of this chronic and life threatening disease. In this journey, there are various treatments available in market to manage diabetes mellitus such as insulin, GLP-1 agonist, biguanides, sulphonyl ureas, glinides, thiazolidinediones targeting the receptors which are discovered decade before. PPAR, GIP, FFA1, melatonin are the recent targets that already in the focus for developing new therapies in the treatment of diabetes. Inspite of numerous preclinical studies very few clinical data available due to which this process is in its initial phase. The review also focuses on the receptors like GPCR 119, GPER, Vaspin, Metrnl, Fetuin-A that have role in insulin regulation and have potential to become future targets in treatment for diabetes that may be effective and safer as compared to the conventional and current treatment approaches.

Serum visfatin as a metabolic biomarker in obese patients with gestational diabetes mellitus

BACKGROUND

Visfatin is an adipokine produced and secreted by the adipose tissue. It exerts an insulin-like effect by the insulin receptor-1 and has a hypoglycemic effect. We aimed to investigate how serum visfatin changes in women with gestational diabetes mellitus (GDM), and whether it is predictive of neonatal outcomes.

METHODS

Visfatin levels were prospectively measured in peripheral blood serum by enzyme immunoassay in 210 pregnant women, 156 of which were diagnosed with GDM, 18 of which suffered from pregnancy-induced hypertension (PIH) and 36 healthy controls.

RESULTS

Patients with obesity class II (median=2.562 ng/mL) and class III (median=6.2940 ng/mL) had higher serum visfatin than overweight patients (median=0.735 ng/mL); (Mann-Whitney U test, P=0.037 and P=0.023, respectively). In GDM patients with BMI above 30, serum visfatin was associated to glycosylated hemoglobin (Spearman correlation test, R=0.26, P=0.045). Women with BMI above 25 treated with insulin had lower serum visfatin levels than those treated with diet only (Mann-Whitney U test, P=0.045). No correlation was found between visfatin and parameters of lipid profile such as HDL, LDL, or triglycerides (Spearman correlation tests, R=-0.051, -0.1, 0.0019; P=0.54, 0.29, 0.98, respectively). We observed that visfatin was not associated with birth weight (Spearman correlation test, R=-0.014, P=0.86) or adverse neonatal outcome as measured by umbilical artery pH below 7.25 (Mann-Whitney U test, P=0.55) or Apgar score below 10 (Mann-Whitney U test, P=0.21).

CONCLUSIONS

In GDM patients with higher BMI, serum visfatin was elevated, correlated positively with glycosylated hemoglobin, and decreased upon treatment with insulin therapy.

IMPACT OF FGFR4 (GLY388ARG) GENE POLYMORPHISM ALONG WITH VISFATIN CYTOKINE AND HIGH MOBILITY GROUP BOX-1 (HMGB1) ON ACUTE CHOLECYSTITIS

OBJECTIVE

The aim: Evaluating the role SNP rs351855 of (FGFR4) gene and estimating the serum concentration of Visfatin cytokine and (HMGB-1) protein in AC patients and in healthy control blood samples.

PATIENTS AND METHODS

Materials and methods: Blood samples were collected from 35 patients and 35 healthy controls, and then the serum was used for ELISA test, another each 2 ml blood were used for DNA extraction and rs351855 of (FGFR4) PCR assay.

RESULTS

Results: there was no significant difference in mean HMG and mean visfatin among (FGFR4) rs351855 genotypes in patients and control group. There was no significant difference in mean (HMG) among (FGFR) rs351855 genotypes in patients` group (p = 0.923); there was also no significant difference in mean visfatin among FGFR rs351855 genotypes in patients` group (p=0.161) rs351855 genotypes showed that the homozygous GG, heterozygous A/G and homozygous AA. Despite these minor differences there was no significant variation (p = 0.323), also no significant difference in frequency distribution of individuals according to FGFR rs351855 G>A SNP polymorphism between patients` and control groups (p = 0.454). The same was applied to recessive and allelic analysis p>0.05.

CONCLUSION

Conclusions: There was no role for (FGFR4) rs351855G/A SNP in disease susceptibility to acute cholecystitis in Iraqi patients. Visfatin cytokine and HMGB-1 protein might act as a good biomarker for diseases.

Circulating Serum Level of Visfatin in Patients with Endometrial Cancer

Obesity is a well-known factor that leads to many diseases including endometrial cancer. The adipose tissue is a heterogeneous organ of internal secretion. Visfatin is a newly discovered protein produced by fat tissues. The purpose of this work was to evaluate serum level concentrations of visfatin in patients with endometrial cancer based on clinical progression and histopathological tumor differentiation. The diagnostic capabilities of visfatin protein in high differentiation (FIGO III and IV) from a lower (FIGO I and II) clinical stage and prognostic degree of cell differentiation (G1 versus G2, G2 versus G3) on the basis of the analysis of the area under the ROC curve are as follows: 0.87, 0.81, and 0.86. Significantly higher concentrations of visfatin have been observed in patients with invasion of the blood vessels (p = 0.02) and lymph node metastases (p = 0.01) in reference to the depth of infiltration of the endometrium (p = 0.004), as well as the size of the tumor (p = 0.003). Visfatin serum concentrations did not differ due to the invasion of the lymphatic vessels only. Visfatin seems to be a good marker of endometrial cancer progress. High visfatin serum level predicts poor prognosis in endometrial cancer patients.

Study of Visfatin Level in Type 1 Diabetic Children and Adolescents

BACKGROUND

Visfatin is an intracellular enzyme, known as nicotinamide phosphoribosyltransferase (Nampt) and pre-B-cell colony-enhancing factor (PBEF-1). It has insulin-mimetic effects and lowers plasma glucose levels.

AIM

The aim of the work was to assess serum concentration of Visfatin in type 1 diabetic children and adolescents and study its relationships with duration of diabetes, body mass index (BMI), glycemic control, insulin dosage, lipid profile and microvascular complications.

MATERIAL AND METHODS

Fifty children and adolescents with type 1 diabetes mellitus were recruited with 30 ages and gender-matched healthy subjects. They were subjected to history taking; anthropometric measurements and chronic diabetic complications were recorded if present. Laboratory analysis included urinary microalbumin, serum triglycerides, HDL, LDL, cholesterol, fasting blood glucose, glycosylated Hb (HbA1c) and serum visfatin which was measured with enzyme-linked immunosorbent assay.

RESULTS

Diabetic patients showed highly significant decrease in the level of visfatin compared to the control group (P = 0.0001). There was significant further decrease in visfatin level in diabetics with microalbuminuria (n = 13) compared to normoalbuminuric patients (n = 37) (P = 0.015). There was highly significant inverse correlation between visfatin level with age (r = -0.379, p = 0.007), BMI (r = -0.418, p = 0.003), waist circumference (r = -0.430, p = 0.002), hip circumference (r = -0.389, p = 0.005) and microalbuminuria (r = -0.323, p = 0.022).

CONCLUSIONS

Type 1 diabetic children and adolescents had a significantly lower visfatin level compared to controls. A marked decrease in the level of visfatin was shown in patients with microalbuminuria with an inverse correlation with BMI suggesting an important role of visfatin in the pathogenesis of type 1 diabetics and type 1 diabetic nephropathy.

Prevailing vitamin D status influences mitochondrial and glycolytic bioenergetics in peripheral blood mononuclear cells obtained from adults

BACKGROUND

Circulating peripheral blood mononuclear cells (PBMCs) are exposed to metabolic and immunological stimuli that influence their functionality. We hypothesized that prevailing vitamin D status [25(OH)D] would modulate the bioenergetic profile of PBMCs derived from humans.

MATERIALS AND METHODS

38 participants (16 males, 22 females) ranging in body fat from 14-51% were studied. PBMCs were isolated from whole blood, counted and freshly seeded for bioenergetic analysis using the Seahorse XF^e96 flux analyser. Whole body energy metabolism via indirect calorimetry, body composition by dual-energy X-ray absorptiometry, and relevant clinical biochemistry were measured. Data was analysed based on 25(OH)D cut-offs of <50nmol/L (Group 1, n=12), 50-75nmol/L (Group 2, n=15) and ≥75nmol/L (Group 3, n=11). A multivariate general linear model adjusting for age, fat mass, fat-free mass, parathyroid hormone and insulin sensitivity was used.

RESULTS

There were significant differences in cellular mitochondrial function between groups. Group 1 had significantly higher basal respiration (p=0.001), non-mitochondrial respiration (p=0.009), ATP production (p=0.001), proton leak (p=0.018), background glycolysis (p=0.023) and glycolytic reserve (p=0.039) relative to either Group 2 or Group 3; the latter two did not differ on any measures. There were no differences in bioenergetic health index (BHI), resting metabolic rates and systemic inflammatory markers between groups.

CONCLUSIONS

Inadequate vitamin D status adversely influenced bioenergetic parameters of PBMCs obtained from adults, in a pattern consistent with increased oxidative metabolism and activation of these cells.

The impact of cryopreservation on human peripheral blood leucocyte bioenergetics

Circulating immune cells are considered a source for biomarkers in health and disease, since they are exposed to nutritional, metabolic and immunological stimuli in the vasculature. Cryopreservation of leucocytes is routinely used for long-term storage and determination of phenotypic/functional changes at a later date. Exploring the role of bioenergetics and mitochondrial (dys)function in leucocytes is often examined by using freshly isolated cells. The aim of the pilot study described herein was to assess leucocyte bioenergetics in cryopreserved cells. Leucocytes were isolated from whole blood, counted and frozen in liquid nitrogen (LN2) for a period of 3 months. Cells were thawed at regular intervals and bioenergetic analysis performed using the Seahorse XFe96 flux analyser. Cryogenic storage reduced cell viability by 20%, but cell bioenergetic responses were largely intact for up to 1 month storage in LN2. However, after 1 month storage, mitochondrial function was impaired as reflected by decreasing basal respiration, ATP production, maximum (MAX) respiration, reserve capacity and coupling efficiency. Conversely, glycolytic activity was increased after 1 month, most notably the enhanced glycolytic response to 25 mM glucose without any change in glycolytic capacity. Finally, calculation of bioenergetic health index (BHI) demonstrated that this potential diagnostic parameter was sensitive to cryopreservation. The present study has demonstrated for the first time that cryopreservation of primary immune cells modified their metabolism in a time-dependent fashion, indicated by attenuated aerobic respiration and enhanced glycolytic activity. Taken together, we recommend caution in the interpretation of bioenergetic responses or BHI in cryopreserved samples.

Serum Visfatin and Leptin in Relation to Childhood Adiposity and Body Fat Distribution: The PIAMA Birth Cohort Study

BACKGROUND/AIMS

Visfatin has been suggested as a marker of visceral adiposity. We hypothesized that visfatin, but not leptin, would be specifically associated with visceral adiposity. We investigated the relation of serum visfatin and leptin with measures of adiposity and body fat distribution in children.

METHODS

Serum leptin and visfatin levels were measured in 1,022 12-year-old children participating in the PIAMA birth cohort. BMI, waist, hip and upper arm circumference were available for all children. Multiple linear regression analyses were conducted to study associations between different anthropometric indices and log serum visfatin and leptin levels.

RESULTS

All anthropometric indices showed positive and strong dose-response relationships with serum leptin. Visfatin was increased only in children with a high waist-to-hip ratio. The effect size was small compared to those observed for leptin and the association was present in overweight children (n = 133) but not in normal weight children.

CONCLUSION

Serum leptin levels strongly increased with increasing adiposity, but were not related to a specific type of fat distribution. In contrast, serum visfatin was associated only with high waist-to-hip ratio in overweight children. Based on our study we would currently not recommend visfatin as a marker of visceral adiposity in the general population of children.

The role of visfatin on the regulation of inflammation and apoptosis in the spleen of LPS-treated rats

The purpose of the present study is to determine if visfatin is involved in inflammation or apoptosis induced by LPS in rat. Forty Wistar rats were divided into four groups: saline group, LPS group, visfatin group and Visfatin + LPS co-stimulated group. Spleen samples from each group of rats were collected for study. The spleen structure was examined by histological imaging. Apoptosis was evaluated with TUNEL reaction. Caspase-3 was detected with immunohistochemistry and western blot. The apoptosis-related genes were detected by qPCR and inflammatory cytokines were tested by ELISA. Our main findings were as follows. (1) Macrophages were markedly increased in the visfatin group compared with the saline group. This finding was confirmed when spleen samples were examined with western blot using CD68 antibody. (2) Visfatin promoted the expression of CD68 and caspase-3 in rat spleen, whereas visfatin could inhibit the expression of CD68 and activated caspase-3 in spleen of LPS-induced acute inflammation. (3) Visfatin had a pro-apoptotic effect on normal rat spleen, whereas it exerted an anti-apoptotic effect during LPS-induced lymphocytes apoptosis in rat spleen. Moreover, the effect of visfatin on cell apoptosis was mediated by the mitochondrial pathway. (4) Visfatin could modulate both the anti-inflammatory cytokines and pro-inflammatory cytokines in rat spleen, such as IL-10, IL-4, IL-6, TNF-α and IL-1β. Taken together, we demonstrate that visfatin could participate in the inflammatory process in rat spleen by modulating the macrophages and inflammatory cytokines. Also, visfatin plays a dual role in the apoptosis in rat spleen, which is mediated by the mitochondrial pathway.

Insulin resistance, serum visfatin, and adiponectin levels are associated with metabolic disorders in chronic hepatitis C virus-infected patients

OBJECTIVE

The aim of this study was to determine the serum levels of visfatin, adiponectin, and insulin resistance (IR) in patients with hepatitis C virus (HCV) infection and their relations to the biochemical markers of hepatitis C.

MATERIALS AND METHODS

This study was carried out on 40 HCV-infected patients and 40 sex/age/BMI-matched healthy adults. Lipid profile, liver function tests, IR, serum adiponectin, and visfatin of all patients were examined. Correlations between IR, adiponectin, visfatin, and other variables were analyzed.

RESULTS

The levels of visfatin and adiponectin were significantly lower in HCV patients compared with healthy controls. However, IR of HCV patients were higher than those of healthy controls. IR was significantly correlated to triglycerides, visfatin was closely related to low-density lipoprotein cholesterol, whereas adiponectin was associated with high-density lipoprotein cholesterol. These results suggest that IR, serum visfatin, and adiponectin levels are associated with metabolic disorders in chronic HCV-infected patients.

CONCLUSION

IR, adiponectin, and visfatin were related to several metabolic markers of HCV, suggesting the characteristics of HCV-related metabolic abnormalities.

Whole-body cryostimulation as an effective method of reducing low-grade inflammation in obese men

This study was aimed to evaluate anti-inflammatory effect of the whole body cryostimulation in obese men. Fourteen subjects (BMI >30 kg m⁻²), divided into two subgroups according to cardiorespiratory fitness: higher (HCF) or lower (LCF), have been exposed to 10 sessions in a cryogenic chamber (−110 °C). Blood samples were collected before, 30 min and 24 h after the first, fifth and last cryostimulation. Coldness exposures affected blood cytokine profile; however, the response depended on subjects’ fitness capacity. Concentrations of pro-inflammatory cytokines in the LCF decreased by 19, 6.8, and 7.4 % in IL-6, resistin, and visfatin, respectively. TNFα in the LCF dropped 4.3-fold compared to baseline, while in the HCF, changes were smaller, yet significant. Anti-inflammatory cytokine IL-10 increased in both groups. No changes in adiponectin and leptin were observed in either group. Obtained results suggest that whole body cryostimulation can be a supplementary method for obese in reducing systemic inflammation.

Inflammatory markers and haptoglobin polymorphism in Saudi with non-insulin-dependent diabetes mellitus

Objectives:

Haptoglobin (Hp) polymorphism associated with clinical evolution of several inflammatory diseases and considered as a predictive factor for development of diabetes complications. We designed the present study to investigate the frequency distribution of Hp phenotypes among Saudi with non-insulin-dependent diabetes mellitus compared to healthy nondiabetic subjects. Moreover, we explored the possibility of relationship between serum levels of inflammatory markers (namely, high-sensitive C-reactive proteins “hs-CRP”, interleukin (IL)-6, and Hp) and Hp phenotypes.

Methods:

In the present case-control study, we enrolled 60 type 2 diabetic patients as the study group and 60 healthy subjects as the control group. We assayed serum levels of Hp and hs-CRP by immunoturbidimetric method; while IL-6 was measured by ELISA. Native polyacrylamide gel electrophoresis was used for determination of Hp phenotypes.

Results:

In type 2 diabetics, serum concentrations of IL-6, hs-CRP, and Hp were significantly elevated and correlated to body mass index. Moreover, there was a significant correlation between plasma glucose level and Hp (r = 0.577, p = 0.000), IL-6 (r = 0.448, p = 0.000), and hs-CRP (r = 0.380, p = 0.001). In addition, data demonstrated a positive correlation between HbA1c and Hp (r = 0.521, p = 0.000), IL-6 (r = 0.420, p = 0.001), and hs-CRP (r = 0.353, p = 0.008). Hp 2-1 phenotype predominated among subjects in both study and control groups. No significant association between Hp phenotypes with any of the investigated inflammatory markers was documented.

Conclusion:

Inflammation may represent the link between type 2 diabetes and obesity. Hp 2-1 was the predominant phenotype among Saudi type 2 diabetics as well as healthy subjects. In addition to Hp; other possible genetic polymorphisms like CRP may have its effect on diabetes through different mechanisms.

Assessment of serum visfatin levels in girls with anorexia nervosa

OBJECTIVE

Visfatin (VISF) is a recently described peptide regulating the process of adipocyte differentiation. Only one pilot study of VISF expression in the fat tissue and its circulating concentrations in a small group of patients with anorexia nervosa (AN) have been published, yet.

DESIGN AND PATIENTS

Cross-sectional assessment of VISF serum concentrations in 195 girls aged 11-18·9 years with AN (n = 87), eating disorders not otherwise specified (NOS; n = 17), simple obesity (OB; n = 30), and healthy controls (H; n = 61).

MEASUREMENTS

Blood samples were collected during the fasting state between 7:00 am-8:30 am. VISF serum concentrations were determined using enzyme immunoassay. Comparisons of VISF levels between groups were performed.

RESULTS

Mean serum VISF concentrations in girls with AN and NOS were significantly lower than those in the H and OB groups. Serum VISF concentrations were higher in the OB than in the H groups. When were calculated per body mass index (BMI), VISF concentrations were significantly lower in the AN, NOS, and OB groups than in healthy controls. Among participants with a normal BMI, serum VISF concentrations correlated positively with BMI (r = 0·27; P < 0·05). In the OB group, a significant, negative correlation between BMI and VISF levels (r = -0·38; P = 0·04) was observed.

CONCLUSIONS

Compared with healthy girls, serum VISF concentrations are decreased in girls with AN. Conversely, obese girls have elevated VISF levels. When calculated per BMI (VISF/BMI), the results in AN and OB groups were lower than in healthy participants.

Visfatin may be a novel marker for identifying stages of essential hypertension in advanced age patients

OBJECTIVE

Visfatin is a peptide that is secreted from visceral fat. It has been reported to be associated with inflammation and endothelial dysfunction. However, little is known about its function in hypertension. Therefore the aim of the present study was to evaluate visfatin levels in patients with hypertension.

METHODS

We studied forty-six newly diagnosed hypertensive patients and 30 healthy participants. In accordance with blood pressure levels reported in the JNC 7 guidelines, hypertensive patients were divided into 2 groups: stage 1 and stage 2. The control group was divided into 2 groups: normal and prehypertensive. Blood pressure (BP) measurements were obtained from each patient. Serum lipid profile, glucose and visfatin levels were measured.

RESULTS

The levels of fasting blood glucose (FBG), total cholesterol, triglyceride (TG), low density lipoprotein cholesterol (LDL-C), BMI, waist circumference were significantly higher in the patient group than those in control subjects (p<0.05). The mean visfatin level was significantly higher in hypertensive patients. In the prehypertensive group, the serum visfatin levels were also significantly higher than in participants with normal blood pressure (p:0.043). There was a significantly positive correlation with visfatin and systolic BP, diastolic BP.

CONCLUSION

We consider that visfatin may be a marker which may be used to illustrate damage even in prehypertensive stage caused by isolated essential HT.

Mechanistic insights into the link between visfatin gene C-1535T polymorphism and coronary artery disease: an in vitro study

Visfatin, a pro-inflammatory cytokine predominantly released from leucocytes, is correlated with coronary artery disease (CAD). We have previously reported that the -1535C>T polymorphism (rs1330082), which located on the promoter region of visfatin, was associated with decreased risk of CAD. Here, we investigated the underlying mechanism by which this polymorphism affects the genetic susceptibility to CAD. The difference of the promoter activities between -1535T variant and -1535C allele was tested by luciferase reporter gene assay. The difference of transcription factor binding activities between T and C allele was evaluated by electrophoretic mobility shift assay. In reporter gene assay, we showed that the T variant had a significantly reduced transcriptional activity compared with the C allele. The T-variant significantly attenuated the promoter binding affinity to nuclear transcription factors and this effect became much obvious after treatment with TNF-α. Moreover, competition experiment revealed that the retarded complex formed by T-1535- or C-1535-probe binding to nuclear extracts was nearly completely inhibited by unlabeled activator protein-1 (AP-1) specific probe, indicating that AP-1 might be the target nuclear effector. Taken together, our data provided potential mechanistic link between the visfatin -1535C>T polymorphism and reduced CAD risk.

Compare the effects of different visfatin concentration on cardiovascular risk factors, adiponectin and insulin resistance in patients with T2DM

AIM

The discovery of new adipokine, visfatin can significantly enhance our knowledge of insulin resistance and diabetes mellitus. We explored the relation of visfatin concentrations to cardiovascular risk factors, adiponectin and insulin resistance criteria in patients with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Fifty-eight patients with T2DM were recruited from the out patients clinic of Shariati Hospital. Laboratory and anthropometric measurements include FBG, OGTT, HbA1c, fasting serum visfatin, insulin and adiponectin, HOMA-IR and hsCRP, weight, height, BMI and WHR were performed in all participants. All of the statistical data were analyzed using the SPSS15 software.

RESULTS

The log(10)-transformed (log) plasma visfatin concentration was in significant positive correlation with age (r=0.286, p=0.033). Patients were divided in two groups by median log visfatin (0.85 ng/mL): group I had low values and group II had high values. In group I the log visfatin was in significant positive correlation with age (r=0.436, p=0.018) and in group II log visfatin was in significant negative correlation with FPG and HbA1c (r>0.4, p<0.05).

CONCLUSION

In conclusion high circulating levels of visfatin could be in healthy relations with cardiovascular risk factors, insulin resistance status and adiponectin in diabetic patients.

Circulating levels of visfatin, resistin and pro-inflammatory cytokine interleukin-8 in acute pancreatitis

BACKGROUND

Resistin and visfatin, hormones produced by adipose tissue, have pro-inflammatory potential; however, their role in acute pancreatitis (AP) has been investigated only rarely.

METHODS

The study group comprised 32 patients with alcoholic AP and 30 controls. In all cases AP was classified as C according to Balthazar's CT score and as severe according to Ranson's criteria. The serum level of visfatin, resistin, and interleukin(IL)-8 immunoassays were measured by ELISA on admission and on the third and fifth day of hospitalization.

RESULTS

On the admission day serum resistin and IL-8 concentrations in AP patients were significantly higher than in controls and they further increased on the third and fifth day of hospitalization. On the admission day serum visfatin levels in AP patients were significantly higher than in controls and further increased on the third day of hospitalization. On the fifth day the levels decreased; however, they were still higher than on admission. The correlation between visfatin and resistin as well as between C-reactive protein and visfatin, resistin and IL-8 levels has been found.

CONCLUSION

In the course of AP, visfatin and resistin levels increase in parallel with C-reactive protein. We speculate that those parameters may provide an additional tool for the prognosis and monitoring of AP. and IAP.

Lack of direct insulin-like action of visfatin/Nampt/PBEF1 in human adipocytes

Visfatin, a protein identified as a secretion product of visceral fat in humans and mice, is also expressed in different anatomical locations, and is known as pre-B cell-colony enhancing factor (PEBF1). It is also an enzyme displaying nicotinamide phosphoribosyltransferase activity (Nampt). The evidence that levels of visfatin correlate with visceral fat mass has been largely debated and widely extended to other regulations in numerous clinical studies and in diverse animal models. On the opposite, the initial findings regarding the capacity of visfatin/Nampt/PEBF1 to bind and to activate the insulin receptor have been scarcely reproduced, and even were contradicted in recent reports. Since the putative insulin mimicking effects of visfatin/Nampt/PEBF1 have never been tested on mature human adipocytes, at least to our knowledge, we tested different human visfatin batches on human fat cells freshly isolated from subcutaneous abdominal fat and exhibiting high insulin responsiveness. Up to 10 nM, visfatin was devoid of clear activatory action on glucose transport in human fat cells while, in the same conditions, insulin increased by more than threefold the basal 2-deoxyglucose uptake. Moreover, visfatin was unable to mimic the lipolysis inhibition induced by insulin. Visfatin definitively cannot be considered as a direct activator of insulin signalling in human fat cells. Nevertheless itsin vivo effects on insulin release and on glucose handling deserve to further study the role of this multifunctional extracellular enzyme in obese and diabetic states.

Expression of inflammatory molecules and associations with BMI in children

BACKGROUND

Adipose tissue secrets several adipokines that have been proposed to be enrolled in many inflammatory pathways. Our aim was to investigate the adipokine expression in adipose tissue and peripheral blood mononuclear cells (PBMCs) in children.

MATERIALS AND METHODS

Thirty-one (17 males and 14 females) healthy children aged 10.9 +/- 1.8 years with a body mass index (BMI) of 19.3 +/- 3.5 kg m(-2) were enrolled. Adipokines (TNF-alpha, IL-6 and leptin) gene expression was quantified by real-time quantitative PCR in adipose tissue and PBMCs from the same children. Their serum levels were also measured.

RESULTS

BMI was positively correlated with leptin gene expression in adipose tissue and with leptin serum levels (beta = 0.476, P = 0.006 and beta = 0.576, P = 0.003 respectively). Leptin's serum levels were positively correlated with leptin gene expression in adipose tissue (beta = 0.462, P = 0.02). Adipose tissue gene expression of leptin and TNF-alpha and serum leptin and TNF-alpha serum levels were positively correlated (beta = 0.752, P < 0.001, beta = 0.311 and P = 0.015 respectively). In PBMCs, a positive correlation between TNF-alpha and IL-6 expression was found (beta = 0.526, P = 0.042).

CONCLUSION

We demonstrated powerful correlations of adipokines gene expression in adipose tissue and PBMCs in children, underlying that these molecules share common pathways related to childhood obesity.

Visfatin serum levels in chronic hepatitis C patients

Visfatin is a new adipokine involved in several processes. The data concerning visfatin in chronic hepatitis C (CHC) is small. To assess visfatin serum concentration and to study its association with biochemical and morphological features in CHC. Seventy nonobese patients with CHC (Group 1) confirmed by the presence of serum hepatitis C virus (HCV)-RNA and 20 healthy volunteers (Group 2), similar in age and BMI with normal fasting glucose and lipid profile were included. Visfatin was significantly increased in Group 1 compared with Group 2 (55.6 +/- 23.1 vs 23.7 +/- 3.8 ng/mL; P < 0.001). Visfatin was negatively associated with necro-inflammatory activity grade (r = -0.36; P = 0.007). The lowest levels were found in patients with the most advanced inflammation: grades 3-4 - 46.8 +/- 17.1, grade 2 - 52.6 +/- 18.4 and grade 1 - 75.2 +/- 27.6 ng/mL; P = 0.017. A significant difference was also shown comparing patients with minimal inflammatory activity to the rest of the cohort (P = 0.009). Visfatin receiver operating characteristic curve analysis for different necro-inflammatory activity - grade 1 vs grades 3-4 with area under the curve 0.81 indicated a good discriminant power for differentiation of moderate/severe inflammation, with the cut-off set at 57.6 ng/mL (sensitivity 75%, specificity 90%, positive predictive value 0.90, negative predictive value 0.75). Serum visfatin concentration increases significantly in CHC patients. These findings suggest that visfatin is important in the pathogenesis of the inflammatory process in CHC. Visfatin may play a dual role as a pro-inflammatory or/and protective factor. The measurement of visfatin serum concentration may serve as an additional tool in distinguishing more advanced grades of the necro-inflammatory activity.

Visfatin plasma concentrations in patients with hyperthyroidism and hypothyroidism before and after control of thyroid function

Alterations in thyroid function are associated with changes in body weight, metabolism, and low-grade inflammation. In several studies, plasma levels of visfatin were found to be associated with body mass index, diabetes, and metabolic syndrome. In our study we aimed to evaluate visfatin levels according to thyroid dysfunction. The study cohort comprised 56 Hashimoto thyroiditis patients with hypothyroidism (43.94+/-14.27 yr), 56 Graves patients with hyperthyroidism (45.87+/-13.28 yr), and 56 euthyroid healthy subjects (45.23+/-7.11 yr) as a control group. In addition, we evaluated the effect of therapy on plasma visfatin levels in 16 hypothyroid and in 25 hyperthyroid patients. Markedly low visfatin levels were found in hyperthyroid patients [9.44 (8.07- 10.8) ng/ml] compared with the hypothyroid [49.93 (40.72- 59.1) ng/ml] and control groups [38.6 (30.6-46.6) ng/ml] (p<0.001, p<0.001). Plasma visfatin levels in patients with hypothyroidism decreased significantly following treatment [58.58 (10.21-190.7) ng/ml vs 40.00 (10.01-102.6) ng/ml; p=0.001]. Plasma visfatin levels increased significantly after antithyroid therapy in patients with hyperthyroidism [7.86 (1.02-19.23) ng/ml vs 12.63 (3.48-110.9) ng/ml; p<0.001]. There were negative correlations between visfatin levels with free T3 (r=-0.719, p<0.001), and free T4 (r=-0.716, p<0.001) levels. There was a positive correlation between visfatin and TSH levels (r=0.701, p<0.001). There was a negative correlation between delta visfatin levels with delta free T3, delta free T4 (r=-0.686, p<0.001; r=-0.624, p<0.001). Visfatin thus seems to be regulated by thyroid hormones. While the influence of thyroid dysfunction on adipocytokine production and release is still poorly understood, the results of our study suggest that the effects of hyper- and hypothyroidism on various metabolic parameters may be partly mediated by visfatin.

Visfatin plasma concentrations in patients with hyperthyroidism and hypothyroidism before and after control of thyroid function

Alterations in thyroid function are associated with changes in body weight, metabolism, and low-grade inflammation. In several studies, plasma levels of visfatin were found to be associated with body mass index, diabetes, and metabolic syndrome. In our study we aimed to evaluate visfatin levels according to thyroid dysfunction. The study cohort comprised 56 Hashimoto thyroiditis patients with hypothyroidism (43.94+/-14.27 yr), 56 Graves patients with hyperthyroidism (45.87+/-13.28 yr), and 56 euthyroid healthy subjects (45.23+/-7.11 yr) as a control group. In addition, we evaluated the effect of therapy on plasma visfatin levels in 16 hypothyroid and in 25 hyperthyroid patients. Markedly low visfatin levels were found in hyperthyroid patients [9.44 (8.07- 10.8) ng/ml] compared with the hypothyroid [49.93 (40.72- 59.1) ng/ml] and control groups [38.6 (30.6-46.6) ng/ml] (p<0.001, p<0.001). Plasma visfatin levels in patients with hypothyroidism decreased significantly following treatment [58.58 (10.21-190.7) ng/ml vs 40.00 (10.01-102.6) ng/ml; p=0.001]. Plasma visfatin levels increased significantly after antithyroid therapy in patients with hyperthyroidism [7.86 (1.02-19.23) ng/ml vs 12.63 (3.48-110.9) ng/ml; p<0.001]. There were negative correlations between visfatin levels with free T3 (r=-0.719, p<0.001), and free T4 (r=-0.716, p<0.001) levels. There was a positive correlation between visfatin and TSH levels (r=0.701, p<0.001). There was a negative correlation between delta visfatin levels with delta free T3, delta free T4 (r=-0.686, p<0.001; r=-0.624, p<0.001). Visfatin thus seems to be regulated by thyroid hormones. While the influence of thyroid dysfunction on adipocytokine production and release is still poorly understood, the results of our study suggest that the effects of hyper- and hypothyroidism on various metabolic parameters may be partly mediated by visfatin.

Visfatin, a new adipocytokine, is predominantly related to inflammation/endothelial damage in kidney allograft recipients

Visfatin, a ubiquitous adipokine, was first described in 2005. It was found to be selectively up-regulated in the adipose tissue and to have insulin-mimetic effects. It has been reported that visfatin is associated with endothelial damage in chronic kidney disease. We investigated plasma visfatin levels (using commercially available kits) in 100 clinically stable kidney allograft recipients. We assessed visfatin markers of coagulation: thrombin-antithrombin complexes, prothrombin fragments 1 + 2; fibrinolysis: tissue plasminogen activator, plasminogen activator inhibitor, plasmin-antiplasmin complexes; endothelial function/injury: von Willebrand factor, thrombomodulin, intracellular adhesion molecule, vascular cell adhesion molecule (VCAM); inflammation: hsCRP and interleukin-6. Visfatin was significantly higher in kidney allograft recipients than in healthy volunteers. Visfatin did not differ significantly between diabetic and nondiabetics, hypertensives and normotensives, patients with and without coronary artery disease, and between male and female subjects. Type of immunosuppressive regimen (mycophenolate mofetil vs azathioprine) did not affect visfatin levels. On univariate analysis, visfatin correlated positively with prothrombin fragments 1 + 2, VCAM, creatinine, high-sensitivity C-reactive protein, and negatively with albumin. In multivariate analysis, only VCAM was associated with visfatin in kidney allograft recipients. Visfatin, which is related to markers of inflammation, may represent a novel link between inflammation and adipocytokines among long-term kidney transplant recipients.

Plasma visfatin level in lean women with PCOS: relation to proinflammatory markers and insulin resistance

OBJECTIVES

The present study was undertaken to investigate the association between plasma visfatin concentrations and inflammatory markers such as interleukin-6 (IL-6) and high-sensitive C-reactive protein (hsCRP) in company with several metabolic parameters in lean women with polycystic ovary syndrome (PCOS).

METHODS

The study group consisted of 21 lean women with PCOS (BMI 20.74 +/- 1.74 kg/m(2)) and 15 healthy, normally menstruating women (BMI 20.85 +/- 2.08 kg/m(2) control group). PCOS was defined according to the Rotterdam criteria. Visfatin, IL-6, hsCRP, hyperandrogenism markers and metabolic markers were examined in all PCOS and control women.

RESULTS

Plasma visfatin level in the PCOS group was higher than that in the control group. Plasma hsCRP and IL-6 levels in PCOS group were similar with the control group. Plasma visfatin levels were positively associated with total cholesterol, high density lipoprotein, hirsutism score, total testosterone and FAI. Plasma visfatin level was negatively associated with SHBG. However, there were no correlation between plasma visfatin level and IL-6 and hsCRP. In multivariate regression analyses, only FAI and high density lipoprotein-cholesterol (HDL-C) showed a significant association with serum visfatin.

CONCLUSION

Our data indicates that plasma visfatin levels are associated with HDL-C and markers of hyperandrogenism, but it is not associated with proinflammatory markers and insulin resistance in lean women with PCOS.

The effects of pioglitazone and metformin on plasma visfatin levels in patients with treatment naive type 2 diabetes mellitus

AIMS

Circulating visfatin levels are altered in insulin resistant states. We evaluated the effects of two insulin-sensitizing hypoglycemic agents on plasma visfatin and adiponectin levels in patients with newly diagnosed and untreated type 2 diabetes mellitus (T2DM).

METHODS

Forty-four patients with T2DM were randomized to treatment either with pioglitazone (15-45mg/day) or metformin (1000-2000mg/day). Plasma visfatin and adiponectin levels and homeostasis model assessment of insulin resistance (HOMA-IR) scores were determined at baseline and at 12th week of treatment.

RESULTS

By the end of the 12th week, fasting plasma glucose, HbA1c, HOMA-IR scores and waist circumferences improved equally in both treatment arms. HDL cholesterol and adiponectin levels increased only in the pioglitazone group (p=0.01 and p=0.003, respectively). On the other hand, metformin treatment had additional regulatory effects on BMI, blood pressure and total and LDL-cholesterol levels (p=0.002, p=0.01, p=0.004, p=0.001 and p<0.001, respectively). Neither pioglitazone nor metformin displayed a significant effect on circulating visfatin concentration.

CONCLUSIONS

Despite improvements in insulin sensitivity and glycemic regulation, either pioglitazone or metformin treatment did not result in any effect on blood visfatin levels in patients with treatment naïve T2DM.

Visfatin expression in subcutaneous adipose tissue of pre-menopausal women: relation to hormones and weight reduction

BACKGROUND

A novel adipokine, visfatin, was found to be related to adiposity in humans and regulated by a number of hormonal signals. The aim of this study was to investigate the relationships of visfatin expression in adipose tissue with potential regulatory factors such as insulin, testosterone and tumor necrosis factor-alpha (TNF-alpha) and to elucidate the effect of a diet induced weight reduction on adipose tissue mRNA expression and plasma levels of visfatin.

MATERIALS AND METHODS

Biopsies of subcutaneous abdominal adipose tissue (SCAAT) and plasma samples were obtained at the beginning of the study from 47 pre-menopausal women (age 38.7 +/- 1.7 years, body mass index (BMI) 27.9 +/- 1.4 kg m(-2)), consisting of 15 lean, 16 overweight and 16 obese subjects. The subgroup of 32 overweight/obese women (age 42.1 +/- 1.9 years, BMI 31.2 +/- 0.9 kg m(-2)) underwent a 12 week hypocaloric weight reducing diet and samples were obtained at the end of the diet. Biopsy samples were analysed for visfatin and TNF-alpha mRNA levels and plasma was analysed for relevant metabolites and hormones.

RESULTS

In the group of 47 subjects visfatin mRNA expression in SCAAT was negatively correlated with plasma free testosterone (r = -0. 363, P < 0.05) and BMI (r = -0.558, P < 0.01) and positively associated with adipose tissue TNF-alpha mRNA expression (r = 0.688, P < 0.01). The diet resulted in the reduction of body weight and in the decrease of plasma insulin, free testosterone and TNF-alpha levels. In the group of overweight/obese subjects visfatin mRNA in SCAAT increased after the diet and the diet induced increase was positively correlated with the magnitude of body weight loss.

CONCLUSION

Visfatin mRNA expression in SCAAT is associated with TNF-alpha expression, plasma free testosterone and BMI in pre-menopausal women. A weight reducing hypocaloric diet results in the increase of visfatin mRNA in SCAAT.