The visfatin gene is associated with glucose and lipid metabolism in a Chinese population

Correlation Analysis of NAMPT rs61330082 Polymorphism in Type 2 Diabetes Mellitus Combined with Hypertension

Introduction

This study aimed to investigate the association of Nicotinamide phosphoribosyl transferase (NAMPT) rs61330082 polymorphism with co-morbid hypertension (HTN) and the progression of hypertension in Chinese patients with type 2 diabetes mellitus (T2DM).

Methods

A total of 453 T2DM patients were genotyped for the polymorphism of rs61330082 using SNP-scan high-throughput technology. These patients were divided into T2DM group (261 patients) and T2DM combined with hypertension group (T2MH, 192 patients). The T2MH group was further categorized into Grade I, Grade II, and Grade III based on the results of the Hypertension Grade Score. Peripheral blood plasma urea, plasma creatinine, renin-angiotensin system (RAS) indexes, and lipid biochemistry indexes were measured in patients and analyzed in relation to NAMTP polymorphisms.

Results

We found that the presence of the NAMPT rs61330082-AA genotype was associated with a significantly increased risk of developing higher-grade hypertension in patients with T2MH. In addition, the A allele of the NAMPT rs61330082 gene displayed more associated in developing a higher grade of hypertension compared to the G allele. Also, the level of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-c) increased with hypertension grade in the NAMPT rs61330082-GG genotype.

Conclusion

NAMPT rs61330082 polymorphism was significantly associated with the progression of hypertension grade in T2MH patients and also affected plasma creatinine and LDL-c levels.

Association between Genotype and the Glycemic Response to an Oral Glucose Tolerance Test: A Systematic Review

The inter-individual variability of metabolic response to foods may be partly due to genetic variation. This systematic review aims to assess the associations between genetic variants and glucose response to an oral glucose tolerance test (OGTT). Three databases (PubMed, Web of Science, Embase) were searched for keywords in the field of genetics, OGTT, and metabolic response (PROSPERO: CRD42021231203). Inclusion criteria were available data on single nucleotide polymorphisms (SNPs) and glucose area under the curve (gAUC) in a healthy study cohort. In total, 33,219 records were identified, of which 139 reports met the inclusion criteria. This narrative synthesis focused on 49 reports describing gene loci for which several reports were available. An association between SNPs and the gAUC was described for 13 gene loci with 53 different SNPs. Three gene loci were mostly investigated: transcription factor 7 like 2 (TCF7L2), peroxisome proliferator-activated receptor gamma (PPARγ), and potassium inwardly rectifying channel subfamily J member 11 (KCNJ11). In most reports, the associations were not significant or single findings were not replicated. No robust evidence for an association between SNPs and gAUC after an OGTT in healthy persons was found across the identified studies. Future studies should investigate the effect of polygenic risk scores on postprandial glucose levels.

Extracellular Nicotinamide Phosphoribosyltransferase as a Surrogate Marker of Prominent Malignant Potential in Colonic Polyps: A 2-Year Prospective Study

Background/aims: The implications of extracellular nicotinamide phosphoribosyltransferase (eNAMPT), a cancer metabokine, in colonic polyps remain uncertain. Methods: A 2-year prospective cohort study of patients who underwent colonoscopy was conducted. Biochemical parameters and serum eNAMPT levels were analyzed at baseline and every 24 weeks postpolypectomy. NAMPT-associated single-nucleotide polymorphisms (SNPs), including rs61330082, rs2302559, rs10953502, and rs23058539, were assayed. Results: Of 532 patients, 80 (15%) had prominent malignant potential (PMP) in colonic polyps, including villous adenomas (n = 18, 3.3%), adenomas with high-grade dysplasia (n = 33, 6.2%), and adenocarcinomas (n = 29, 5.5%). Baseline associations were as follows: colonic polyp pathology (p < 0.001), total cholesterol (p = 0.019), and neutrophil-to-lymphocyte ratio (p = 0.023) with eNAMPT levels; and age (p < 0.001), polyp size (p < 0.001), and eNAMPT levels (p < 0.001) with polyp pathology. Higher baseline eNAMPT levels were noted in patients harboring polyps with PMP than in patients without PMP (p < 0.001), and baseline eNAMPT levels significantly predicted PMP (cutoff: >4.238 ng/mL, p < 0.001). Proportions of eNAMPT-positive glandular and stromal cells were higher in polyps with PMP than in polyps without PMP (64.55 ± 11.94 vs. 14.82 ± 11.45%, p = 0.025). eNAMPT levels decreased within 48 weeks postpolypectomy (p = 0.01) and remained stable afterward regardless of PMP until 96 weeks postpolypectomy. However, those with PMP had a higher degree of eNAMPT decline within 24 weeks (p = 0.046). All investigated SNPs were in linkage disequilibrium with each other but were not associated with eNAMPT levels. Conclusion: With a link to inflammation and lipid metabolism, along with its decreasing trend after polypectomy, serum eNAMPT may serve as a surrogate marker of PMP in colonic polyps. In situ probing of the NAMPT-associated pathway holds promise in attenuating PMP, as much of the eNAMPT likely originates from colonic polyps.

Preoperative plasma visfatin may have a dual effect on the occurrence of postoperative delirium

BACKGROUND

Visfatin is considered to be a "novel pro-inflammatory cytokine." Neuroinflammatory response is one of the important mechanisms of postoperative delirium (POD). The relationship between preoperative plasma visfatin and POD is unclear.

OBJECTIVE

To investigate the relationship between preoperative plasma visfatin concentrations and POD (primary outcome) in older hip fracture patients and to explore whether it affects POD through inflammatory factors.

MATERIALS AND METHODS

This prospective cohort study enrolled 176 elderly patients who were scheduled for hip fracture surgery. Preoperative plasma was collected on the morning of surgery, and visfatin levels were measured. Interleukin (IL)-1 and IL-6 were measured using patients' plasma collected on the first day after surgery. We used the 3-min diagnostic interview for Confusion Assessment Method-defined delirium (3D-CAM) twice daily within the 2 days after surgery to assess whether POD had occurred. Restricted cubic splines and piecewise regression were used to explore the relationship between preoperative plasma visfatin concentrations and POD, and further mediation analysis was used to verify whether visfatin plays a role in POD through regulating inflammatory factors.

RESULTS

The incidence of POD was 18.2%. A J-shaped association was observed between preoperative plasma visfatin levels and POD. The risk of POD decreased within the lower visfatin concentration range up to 37.87 ng/ml, with a hazard ratio of 0.59 per 5 ng/ml [odds ratio (OR) = 0.59, 95% confidence interval (CI) = 0.37-0.95], but the risk increased above this concentration (P for non-linearity < 0.001, with a hazard ratio of 1.116 per 10 ng/ml; OR = 1.10, 95% CI = 1.02-1.23). Mediation effect analysis showed that when the plasma visfatin concentration was higher than 37.87 ng/ml, the effect of visfatin on POD was mediated by IL-6 (p < 0.01). A significant indirect association with postoperative plasma IL-6 was observed between preoperative plasma visfatin and POD (adjusted β = 0.1%; 95% CI = 4.8∼38.9%; p < 0.01).

CONCLUSION

Visfatin is the protective factor in POD when the preoperative plasma visfatin concentration is below 37.87 ng/ml, but when it exceeds 37.87 ng/ml, the visfatin concentration is a risk factor for POD, which is mediated by postoperative plasma IL-6. The results suggest that preoperative visfatin may have a dual effect on the POD occurrence.

CLINICAL TRIAL REGISTRATION

[www.ClinicalTrials.gov], identifier [ChiCTR21 00052674].

Immunohistochemical identification and assessment of the location of leptin, visfatin and chemerin in the liver of men with different body mass index

Background

Adipokines such as leptin, visfatin and chemerin play a pivotal role not only in the pathogenesis of excessive weight gain but also impact on hepatic metabolism. However, alterations in the production of these peptides in the liver of overweight individuals have not been fully elucidated yet. The aim of the study was to evaluate changes in leptin, visfatin and chemerin biosynthesis in the liver of men with different BMI.

Methods

Fourteen adult men without symptoms from the digestive system were recruited. Research material consisted of liver samples. Study participants were divided into two groups: lean (BMI ≤ 25 kg/m²) and overweight subjects (BMI > 25 kg/m²). Paraffin liver sections were processed by immunohistochemistry for detection of leptin, visfatin and chemerin. Hepatic expression of leptin, visfatin and chemerin genes was determined by qRT-PCR method.

Results

Increased immunoreactivity for leptin and chemerin, and decreased immunoreaction for visfatin were observed in the liver of overweight men in comparison to lean subjects. Overweight subjects with hepatic steatosis displayed increased immunoreactivity for leptin and weaker immunoreaction against visfatin and chemerin in the liver, compared to individuals with normal organ structure. Expression of leptin and chemerin was enhanced in the liver of overweight individuals, with the highest expression observed in subjects with hepatic steatosis. Conversely, expression of visfatin in the male liver was decreased in overweight subjects and those with and liver steatosis.

Conclusions

The present study proves that the expression of leptin, visfatin and chemerin in the male liver is altered in overweight individuals. Our report also indicates the potential importance of these peptides in hepatic steatosis associated with overweight.

Accelerated cardiovascular risk after viral clearance in hepatitis C patients with the NAMPT-rs61330082 TT genotype: An 8-year prospective cohort study

Involvement of extracellular nicotinamide phosphoribosyltransferase (eNAMPT, i.e., visfatin or pre-B-cell colony-enhancing factor), a cancer metabokine, in chronically hepatitis C virus (HCV)-infected (CHC) patients with sustained virological responses (SVRs) remains elusive. This 8-year prospective cohort study evaluated eNAMPT profiles of 842 consecutive CHC patients, including 519 who had completed an anti-HCV therapy course and pre-therapy and 24-week post-therapy surveys. For 842 patients, pre-therapy associations were HCV RNA, homeostatic model assessment for insulin resistance (HOMA-IR) index, and body mass index with eNAMPT levels, and NAMPT-rs61330082 T allele with total cholesterol levels. NAMPT-rs10953502, NAMPT-rs2058539, and NAMPT-rs61330082 were in a linkage disequilibrium block, which was associated with total cholesterol levels. Compared to pre-therapy levels, at 24 weeks post-therapy, decreased eNAMPT and increased lipid levels were observed in SVR patients (n = 427). Among SVR patients, higher cumulative incidences of cardiovascular events occurred in those with a NAMPT-rs61330082 TT genotype than those with non-TT genotypes (28.2% vs. 8.4%, p < 0.001). NAMPT-rs61330082 TT genotype was independently associated with incident cardiovascular events (95% CI hazard ratio (HR): 1.88-10.37; HR: 4.415); no eNAMPT profiles were associated with incident malignancies. Of CHC patients, hepatic vascular endothelial cells and baseline peripheral leukocytes expressed higher eNAMPT levels than controls, and peripheral eNAMPT-positive leukocyte proportions decreased after SVR. During HCV infection, eNAMPT involvement in glucose metabolism was modulated by HCV RNA linked to lipid metabolism and NAMPT-associated SNPs. Hepatic endothelial cells and peripheral leukocytes potentially secrete eNAMPT. Caution is required for incident cardiovascular events in SVR patients with NAMPT-rs61330082 TT genotype.

The Role of Visfatin (Adipocytokine) Biomarker in Oral Health and Diseases among Nonobese Indian Population: A Proteomic Assay

Visfatin is an adipocytokine and a potential biomarker encoded by the nicotinamide phosphoribosyltransferase gene. It belongs to the nicotinic acid phosphoribosyltransferase family and involved in various metabolic processes and aging. The aim of this study was to evaluate the role of visfatin biomarker in oral diseases like periodontitis. A total of 60 patients (20–50 years) were included in this study, and they were divided into three groups. Group I consisted of 20 subjects with healthy periodontium, group II consisted of 20 subjects with generalized moderate gingivitis, and group III consisted of 20 subjects with generalized periodontitis. The clinical periodontal parameters, including plaque index, gingival index, probing pocket depth, and clinical attachment levels, were recorded, and saliva samples were collected. Salivary visfatin concentrations were assessed using standard enzyme-linked immunosorbent assay. The results of the study showed that the visfatin concentrations were higher in patients with gingivitis and periodontitis compared with those of healthy individuals. Visfatin was found highest in group III (38.22 ± 3.38 ng/mL) followed by group II (26.66 ± 2.24 ng/mL) and the group I (25.60 ± 2.19 ng/mL). Thus, salivary visfatin is a potential inflammatory biomarker and acts as a mediator in the pathogenesis of periodontal disease and, might serve as a diagnostic and therapeutic biomarker in oral diseases like periodontitis.

Genetic Association of Hepatitis C-Related Mixed Cryoglobulinemia: A 10-Year Prospective Study of Asians Treated with Antivirals

Genetic profiles of hepatitis C virus (HCV)-associated mixed cryoglobulinemia (MC) in Asians remain elusive. A 10-year prospective cohort study was conducted with 1043 consecutive HCV Ab-positive Taiwanese surveyed with 13 single nucleotide polymorphisms (SNPs). Of 1043, 589 (56.5%) had baseline MC, 934 (89.5%) had positive HCV RNA, 796 completed anti-HCV therapy, and 715 had sustained virological responses (SVRs). SNP associations were surveyed withgenotypic, allelic, trend, permutation and multivariate analyses. At baseline, higher male sex and MC rates were noted in HCV RNA-positive than RNA-negative patients; higher female sex and positive HCV RNA rates but lower HCV RNA levels were noted in patients with than those without MC. Baseline associations were: HLA II-rs9461776 A allele, IFNL3-rs12979860 T allele, SERPINE1-rs6976053 C allele and MC with HCV RNA positivity; IFNL3-rs12979860 C allele, ARNTL-rs6486122 T allele and HCV RNA positivity with baseline MC. In SVR patients, RETN-rs1423096 C allele and SERPINE1-rs6976053 T allele were associated with 24-week and 10-year post-therapy MC, respectively. Conclusions: HCV RNA, IFNL3-rs12979860 and ARNTL-rs6486122 were associated with baseline MC; RETN-rs1423096 and SERPINE1-rs6976053 were associated with short- and long-term post-therapy MC in SVR patients, respectively. Links with HCV RNA and immune-associated SNPs suggest MC an immune reaction to expel HCV.

Adipose Tissue Immunomodulation: A Novel Therapeutic Approach in Cardiovascular and Metabolic Diseases

Adipose tissue is a critical regulator of systemic metabolism and bodily homeostasis as it secretes a myriad of adipokines, including inflammatory and anti-inflammatory cytokines. As the main storage pool of lipids, subcutaneous and visceral adipose tissues undergo marked hypertrophy and hyperplasia in response to nutritional excess leading to hypoxia, adipokine dysregulation, and subsequent low-grade inflammation that is characterized by increased infiltration and activation of innate and adaptive immune cells. The specific localization, physiology, susceptibility to inflammation and the heterogeneity of the inflammatory cell population of each adipose depot are unique and thus dictate the possible complications of adipose tissue chronic inflammation. Several lines of evidence link visceral and particularly perivascular, pericardial, and perirenal adipose tissue inflammation to the development of metabolic syndrome, insulin resistance, type 2 diabetes and cardiovascular diseases. In addition to the implication of the immune system in the regulation of adipose tissue function, adipose tissue immune components are pivotal in detrimental or otherwise favorable adipose tissue remodeling and thermogenesis. Adipose tissue resident and infiltrating immune cells undergo metabolic and morphological adaptation based on the systemic energy status and thus a better comprehension of the metabolic regulation of immune cells in adipose tissues is pivotal to address complications of chronic adipose tissue inflammation. In this review, we discuss the role of adipose innate and adaptive immune cells across various physiological and pathophysiological states that pertain to the development or progression of cardiovascular diseases associated with metabolic disorders. Understanding such mechanisms allows for the exploitation of the adipose tissue-immune system crosstalk, exploring how the adipose immune system might be targeted as a strategy to treat cardiovascular derangements associated with metabolic dysfunctions.

Nasser S, Younis N, Bhagani H, Al-Dhaheri Y, Pintus G, Eid AA, El-Yazbi AF, Eid AH. Visfatin: A Possible Role in Cardiovasculo-Metabolic Disorders

Visfatin/NAMPT (nicotinamide phosphoribosyltransferase) is an adipocytokine with several intriguing properties. It was first identified as pre-B-cell colony-enhancing factor but turned out to possess enzymatic functions in nicotinamide adenine dinucleotide biosynthesis, with ubiquitous expression in skeletal muscles, liver, cardiomyocytes, and brain cells. Visfatin exists in an intracellular (iNAMPT) and extracellular (eNAMPT) form. Intracellularly, visfatin/iNAMPT plays a regulatory role in NAD⁺ biosynthesis and thereby affects many NAD-dependent proteins such as sirtuins, PARPs, MARTs and CD38/157. Extracellularly, visfatin is associated with many hormone-like signaling pathways and activates some intracellular signaling cascades. Importantly, eNAMPT has been associated with several metabolic disorders including obesity and type 1 and 2 diabetes. In this review, a brief overview about visfatin is presented with special emphasis on its relevance to metabolic diseases. Visfatin/NAMPT appears to be a unique molecule with clinical significance with a prospective promising diagnostic, prognostic, and therapeutic applications in many cardiovasculo-metabolic disorders.

Implications of visfatin genetic variants in the metabolic profile of the Romanian pediatric population

Background: Conflictual results regarding the relationship between plasmatic level of visfatin and obesity could be explained by the influence of the gene variants involved in the synthesis or action of these hormones.

Objectives: The present study examined the potential implication of single nucleotide polymorphisms (SNPs) of nicotinamide phosphoribosyltransferase (NAMPT) gene that encodes visfatin, in obesity, in a Romanian pediatric population.

Method: A case-control study was conducted on a group of 213 children, divided into two: the case group - 130 overweight and obese children with BMI >1 SD, and the control group - 83 children with normal BMI. The variables analyzed were age, sex, anthropometric parameters, body composition based on bioimpedance analysis, lipid profile, visfatin and insulin plasmatic levels, rs4730153 and rs2302559 visfatin SNPs.

Results: Significant associations were not found between rs4730153 and rs2302559 visfatin SNPs and obesity. Regarding lipid metabolism, there are statistically significant differences between triglyceride levels according to NAMPT rs2302559 genotypes (p=0.045), with heterozygous genotype having the highest level of triglycerides, and also between cholesterol levels according to NAMPT rs4730153 genotypes (p=0.030), with carriers of heterozygote genotype having the highest level of cholesterol. There is a statistically significant difference between the studied parameters in the investigated groups, regarding cholesterol, in carrier of wild-type genotype of NAMPT rs2302559 (p=0.040) and carrier of wild-type genotype of NAMPT rs4730153 (p=0.036). We observed no association of NAMPT rs4730153 and rs2302559 with visfatin levels in the studied groups. Visfatin level was lower in the case group and was correlated with weight (p=0.042), abdominal circumference (p=0.010), waist to height ratio (p=0.040), but not with the elements of the metabolic profile.

Conclusion: NAMPT rs2302559 and rs4730153 polymorphisms do not seem to have a major impact in the development of obesity in children, however there may be an association with lipid profile, but further studies are needed..

The Relationship Between Serum Visfatin Levels and Metabolic Parameters According To Different Body Mass Indexes

Aim: The aim of this study was to investigate the relationship between body mass index and serum visfatin and metabolic parameters in subjects with different body mass indexes. Methods: Patients enrolled in this study were applied a questionnaire including their personal information, dietary habits and status of physical activities. Their length and body weight were measured, body mass indexes were calculated, and body fat percentage and waist circumference were measured. In addition, routine biochemical parameters (total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol, fasting blood glucose, fasting insulin) and serum visfatin levels of patients were measured, and they were evaluated according to their body mass indexes. Results: Serum visfatin levels of patients were not found to be correlated with their age, gender and waist circumference, but a moderate negative correlation was determined with body fat percentage. Also there was a negative correlation between body mass indexes and serum visfatin level. While there was no statistically significant relation between serum visfatin level and cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol as well as VLDL-cholesterol, a negative correlation was found between serum visfatin and fasting glucose and fasting insulin levels. Conclusion: Serum visfatin levels resulted lower in patients with high body mass indexes. Negative correlation between serum visfatin levels and fasting blood glucose as well as fasting blood insulin indicates that serum visfatin levels may be associated with the mechanism of insulin resistance in obesity. Keywords: visfatin, body mass index, metabolic profile

The HindIII and PvuII polymorphisms of lipoprotein lipase (LPL) gene reduce the risk of ischemic stroke (IS): A meta-analysis

BACKGROUND

Lipoprotein lipase (LPL) polymorphisms were suggested to be the risk factor for ischemic stroke (IS). However, controversial results were obtained. Our objective was to investigate the association of LPL polymorphisms at Ser447Ter, HindIII (+/-), and PvuII (+/-) with IS risk.

METHODS

Literatures search were carried out on databases: PubMed, Web of science, the Cochrane database of system reviews, Chinese National Knowledge Infrastructure, and Embase. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated to detect the relationship between LPL polymorphisms and the risk of IS.

RESULTS

No significant association was detected between LPL Ser447Ter and IS in allelic, dominant, or recessive models (P > .05). Significant lower frequencies of allelic and dominant models of LPL HindIII (+/-) and PvuII (+/-) in cases were detected (HindIII (+/-): allelic model: P = .0002, OR[95%CI] = 0.80 [0.71, 0.90]; dominant model: P = 0.003, OR[95%CI] = 0.80 [0.69, 0.92]; PvuII (+/-): allelic model: P < 0.0001, OR[95%CI] = 0.75[0.65-0.86]; dominant model: P = 0.02, OR[95%CI] = 0.67[0.48-0.93]). And the recessive model of PvuII (+/-) was significantly associated with the IS risk (P = .01, OR[95%CI] = .71[0.55-0.93]). Subgroup analysis stratified by ethnicity showed that the frequencies of allelic, dominant, and recessive models of HindIII (+/-), as well as dominant model of PvuII (+/-) were significant lower in Asian cases (HindIII (+/-): allelic model: P < .00001, OR[95%CI] = 0.69 [0.59, 0.79]; dominant model: P < .0001, OR[95%CI] = 0.69 [0.58, 0.83]; recessive model: P = .005, OR[95%CI] = 0.66 [0.50, 0.89]; PvuII (+/-): dominant model: P = .0008, OR[95%CI] = 0.66 [0.51-0.84]), but not in Caucasian cases (P > .05). In addition, the frequencies of allelic and recessive models of PvuII (+/-) significantly decreased in Caucasian cases (P < .05).

CONCLUSION

the HindIII (+/-) and PvuII (+/-), but not the Ser447Ter might be the protective factors for IS.

Dietary fat intake associated with bone mineral density among visfatin genotype in obese people

Osteoporosis and adipose tissue are closely related with many contradictions. Visfatin is an adipokine that is related to osteoporosis and adiposity. This nutrigenomics study examined the interaction between visfatin genotypes and dietary fat intake, with regard to bone mineral density (BMD) among an obese population. In this cross-sectional study, 336 subjects were enrolled; the mean age was 38·25 (sd 11·69) years and the mean BMI was 31·79 (sd 4·77) kg/m2. Laboratory measurements were lipid profile, insulin and fasting blood sugar. Bone density measurements were assessed by dual-energy X-ray absorptiometry. Dietary data were collected through a 3-d 24-h dietary recall. Genotyping for visfatin gene SNP (rs2110385) was performed by the PCR-restriction fragment length polymorphism method. The frequency of GG, GT and TT genotypes were 33·92 48·51 and 17·54 %, respectively, and 86·6 % of participants were women. The results showed that subjects with TT genotypes had significantly higher lumbar BMD, T score and z score (P<0·0001). After categorisation by percentage of fat intake (30 % of total energy content as a cut-off point), no interaction was found, but when categorised by fat types, we found an interaction between visfatin genotypes and dietary PUFA intake in terms of the hip T score and z score (P=0·043, B= -0·08; P=0·04, B= -0·078, respectively). There was a significant relationship between high PUFA intake and lower energy and protein intake. When participants were categorised by median PUFA intake (22·8 g), it was concluded that subjects with GG genotype who had high PUFA-intake diets had lower hip z scores and T scores, unlike the other genotypes.

Obesity and Cardiovascular Risk: Variations in Visfatin Gene Can Modify the Obesity Associated Cardiovascular Risk. Results from the Segovia Population Based-Study. Spain

Objectives

Our aim was to investigate if genetic variations in the visfatin gene (SNPs rs7789066/ rs11977021/rs4730153) could modify the cardiovascular-risk (CV-risk) despite the metabolic phenotype (obesity and glucose tolerance). In addition, we investigated the relationship between insulin sensitivity and variations in visfatin gene.

Material and Methods

A population-based study in rural and urban areas of the Province of Segovia, Spain, was carried out in the period of 2001–2003 years. A total of 587 individuals were included, 25.4% subjects were defined as obese (BMI ≥30 Kg/m²).

Results

Plasma visfatin levels were significantly higher in obese subjects with DM2 than in other categories of glucose tolerance. The genotype AA of the rs4730153 SNP was significantly associated with fasting glucose, fasting insulin and HOMA-IR (Homeostasis model assessment-insulin resistance) after adjustment for gender, age, BMI and waist circumference.

The obese individuals carrying the CC genotype of the rs11977021 SNP showed higher circulating levels of fasting proinsulin after adjustment for the same variables.

The genotype AA of the rs4730153 SNP seems to be protective from CV-risk either estimated by Framingham or SCORE charts in general population; and in obese and non-obese individuals. No associations with CV-risk were observed for other studied SNPs (rs11977021/rs7789066).

Conclusions

In summary, this is the first study which concludes that the genotype AA of the rs4730153 SNP appear to protect against CV-risk in obese and non–obese individuals, estimated by Framingham and SCORE charts. Our results confirm that the different polymorphisms in the visfatin gene might be influencing the glucose homeostasis in obese individuals.

Indels within the bovine visfatin gene affect its mRNA expression in longissimus muscle and subcutaneous fat

Abstract. Visfatin, an adipokine hormone produced primarily by visceral adipose tissue in mammals, has been identified as having a crucial role in growth and development of skeletal muscle and lipids. In this research, the effects of two indel loci (35 bp indel: AC_000161.1: g. 20540–20541 Ins ACTGGAATTCTAGTTTAAAAATTGCTACTAATGAA located in intron 4; 6 bp indel: AC_000161.1: g. 25873–25878 Del: TAAAAA located in intron 5) of the visfatin gene on mRNA expression levels were studied by means of real-time quantitative PCR (qPCR) in longissimus muscle and subcutaneous fat from 95 Qinchuan cattle. Firstly, visfatin expression level in longissimus muscle of fetal cattle was prominently greater than that in calves and adult cattle (P < 0.05). The expression level of visfatin in subcutaneous fat was notably higher than that in longissimus muscle of calves and adult cattle (P < 0.05). Secondly, there were three genotypes (ins/ins, del/del and ins/del) and two genotypes (ins/del and ins/ins) detected in the 35 bp locus and 6 bp locus, respectively. Visfatin showed a minimum expression level in longissimus muscle in the homozygous deletion genotype at the 35 bp indel locus. Especially in calves, expression of visfatin was significantly greater in the heterozygous genotype than that in the homozygous insertion genotpye (P < 0.05). No statistical differences were found among visfatin expression level based on genotypes in the 6 bp indel locus (P > 0.05). Compared to heterozygous genotype, the expression level of homozygous insertion genotype was lower in longissimus muscle but greater in subcutaneous fat. These results imply that the expression levels of bovine visfatin vary with age and its indels might be putative variants mediating the expression of the bovine visfatin gene. This study provides useful information for further functional studies of bovine visfatin.

Physiological and pathophysiological roles of NAMPT and NAD metabolism

Nicotinamide phosphoribosyltransferase (NAMPT) is a regulator of the intracellular nicotinamide adenine dinucleotide (NAD) pool. NAD is an essential coenzyme involved in cellular redox reactions and is a substrate for NAD-dependent enzymes. In various metabolic disorders and during ageing, levels of NAD are decreased. Through its NAD-biosynthetic activity, NAMPT influences the activity of NAD-dependent enzymes, thereby regulating cellular metabolism. In addition to its enzymatic function, extracellular NAMPT (eNAMPT) has cytokine-like activity. Abnormal levels of eNAMPT are associated with various metabolic disorders. NAMPT is able to modulate processes involved in the pathogenesis of obesity and related disorders such as nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) by influencing the oxidative stress response, apoptosis, lipid and glucose metabolism, inflammation and insulin resistance. NAMPT also has a crucial role in cancer cell metabolism, is often overexpressed in tumour tissues and is an experimental target for antitumour therapies. In this Review, we discuss current understanding of the functions of NAMPT and highlight progress made in identifying the physiological role of NAMPT and its relevance in various human diseases and conditions, such as obesity, NAFLD, T2DM, cancer and ageing.

NAMPT and NAPRT1: novel polymorphisms and distribution of variants between normal tissues and tumor samples

Nicotinamide phosphoribosyltransferase (NAMPT) and nicotinate phosphoribosyltransferase domain containing 1 (NAPRT1) are the main human NAD salvage enzymes. NAD regulates energy metabolism and cell signaling, and the enzymes that control NAD availability are linked to pathologies such as cancer and neurodegeneration. Here, we have screened normal and tumor samples from different tissues and populations of origin for mutations in human NAMPT and NAPRT1, and evaluated their potential pathogenicity. We have identified several novel polymorphisms and showed that NAPRT1 has a greater genetic diversity than NAMPT, where any alteration can have a greater functional impact. Some variants presented different frequencies between normal and tumor samples that were most likely related to their population of origin. The novel mutations described that affect protein structure or expression levels can be functionally relevant and should be considered in a disease context. Particularly, mutations that decrease NAPRT1 expression can predict the usefulness of Nicotinic Acid in tumor treatments with NAMPT inhibitors.

Correlation of visfatin levels and lipoprotein lipid profiles in women with polycystic ovary syndrome undergoing ovarian stimulation

The aim of this study was to determine serum and follicular fluid (FF) visfatin levels in age and weight-matched women with polycystic ovary syndrome (PCOS) and normally ovulating subjects undergoing controlled ovarian stimulation and correlate them with their lipid and lipoprotein levels. We included 80 PCOS women (40 lean and 40 overweight) and 80 age- and weight-matched controls, enrolled in the IVF program. In PCOS women, we determined significantly increased serum and FF visfatin as well as serum levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, apolipoprotein B, lipoprotein(a) and homocysteine, while high-density lipoprotein cholesterol and apolipoprotein A1 were significantly lower compared to controls. Serum visfatin levels positively correlated with total cholesterol, LDL cholesterol, triglycerides, lipoprotein(a) and homocysteine levels and negatively with apolipoprotein A1. FF visfatin levels positively correlated with triglycerides and homocysteine and negatively with apolipoprotein A1. Dyslipidemia is common in reproductive age women with PCOS exposing them to risk for cardiovascular diseases. However, the detailed role of visfatin on lipoprotein lipid profile awaits further clarification through future investigation.

Visfatin, Leptin, and TNF-α: Interrelated Adipokines in Insulin-Resistant Clinical and Subclinical Hypothyroidism

PURPOSE

This study is designed to evaluate the interrelationships among adipokines-visfatin, leptin, and tumor necrosis factor-α (TNF-α)- and insulin resistance (IR) in overt (n = 40) and subclinic hypothyroid (n = 25) patients and compare our findings with sex and body mass index-matched healthy controls (n = 25).

METHODS

Serum visfatin, leptin, and TNF-α levels were measured by enzyme-linked immunosorbent assay and C-reactive protein by immunoturbidimetry. Thyroid status (TSH, FT3, FT4) and lipid status (triglyceride, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, total cholesterol) parameters were measured. IR was determined by homeostatic model assessment (HOMA-IR) and McAuley (McA) indices.

RESULTS

HOMA-IR (p < 0.05) and McA indices (p < 0.01) revealed the presence of IR in overt hypothyroid patients. C-reactive protein, TNF-α, leptin, and visfatin levels were significantly higher (p < 0.01, p < 0.01, p < 0.001, and p < 0.001) in overt hypothyroid patients than euthyroid control group. Subclinic hypothyroid patients were observed to have significantly higher leptin and visfatin levels (p < 0.05) than euthyroid control group. In overt hypothyroid patients, we found plasma visfatin to be significantly positively correlated with HOMA-IR index (r = 0.336, p < 0.05) and body mass index (r = 0.445, p < 0.01) and negatively correlated with McA index (r = -0.574, p < 0.01).

CONCLUSION

This study demonstrates the presence of IR in overt hypothyroid patients by HOMA and McA indices. Increased levels of visfatin, leptin, and TNF-α in overt and subclinic hypothyroid patients and the correlations among these adipokines highlighten their crucial role in the IR-associated disorders.

Expression and regulation of nampt in human islets

Nicotinamide phosphoribosyltransferase (Nampt) is a rate-limiting enzyme in the mammalian NAD+ biosynthesis of a salvage pathway and exists in 2 known forms, intracellular Nampt (iNampt) and a secreted form, extracellular Nampt (eNampt). eNampt can generate an intermediate product, nicotinamide mononucleotide (NMN), which has been reported to support insulin secretion in pancreatic islets. Nampt has been reported to be expressed in the pancreas but islet specific expression has not been adequately defined. The aim of this study was to characterize Nampt expression, secretion and regulation by glucose in human islets. Gene and protein expression of Nampt was assessed in human pancreatic tissue and isolated islets by qRT-PCR and immunofluorescence/confocal imaging respectively. Variable amounts of Nampt mRNA were detected in pancreatic tissue and isolated islets. Immunofluorescence staining for Nampt was found in the exocrine and endocrine tissue of fetal pancreas. However, in adulthood, Nampt expression was localized predominantly in beta cells. Isolated human islets secreted increasing amounts of eNampt in response to high glucose (20 mM) in a static glucose-stimulated insulin secretion assay (GSIS). In addition to an increase in eNampt secretion, exposure to 20 mM glucose also increased Nampt mRNA levels but not protein content. The secretion of eNampt was attenuated by the addition of membrane depolarization inhibitors, diazoxide and nifedipine. Islet-secreted eNampt showed enzymatic activity in a reaction with increasing production of NAD+/NADH over time. In summary, we show that Nampt is expressed in both exocrine and endocrine tissue early in life but in adulthood expression is localized to endocrine tissue. Enzymatically active eNampt is secreted by human islets, is regulated by glucose and requires membrane depolarization.

Serum visfatin levels in women with polycystic ovary syndrome

The aim of this study is to determine the serum levels of visfatin in patients with polycystic ovary syndrome (PCOS) and to understand its correlations with other metabolic and hormonal parameters. Thirty-seven patients with PCOS and 30 women without concomitant disease were included in this study. Serum visfatin levels were similar in patients with PCOS and control group. Visfatin levels were higher in normal weight PCOS when compared with obese PCOS, but it did not reach statistical significance. Visfatin levels correlated negatively with fasting blood glucose, total cholesterol (TC), low-density lipoprotein (LDL) and lipoprotein-a levels in PCOS patients. CRP levels increased both in obese PCOS and in obese controls. Plasma visfatin levels had no correlation with homeostasis model assessment-insulin resistance and fasting insulin levels, but the negative correlation between plasma visfatin levels and lipoprotein-a, fasting plasma glucose, TC and LDL levels may indicate a role for visfatin in cardiovascular disease independent of insulin resistance.

Serum visfatin levels, adiposity and glucose metabolism in obese adolescents

OBJECTIVE

Visfatin, an adipokine, has insulin-mimetic effects. The main determinants of both the production and the physiologic role of visfatin are still unclear. The aim of this study is to determine the relation of serum visfatin to adiposity and glucose metabolism.

METHODS

40 pubertal adolescents (20 females, 20 males; age range: 9-17 years) with exogenous obesity and 20 age- and sex-matched healthy adolescents (10 females, 10 males) were enrolled in the study. Oral glucose tolerance test (OGTT) was performed in the obese group. Serum glucose, insulin and visfatin levels were analyzed in the fasting state in the controls and at 0, 60 and 120 minutes during the OGTT in the obese group.

RESULTS

The obese group had higher serum visfatin levels than the control group [11.6 (3.3-26) ng/mL vs. 7.5 (3.3-10.5) ng/mL, p<0.001[. Visfatin levels were correlated positively with body mass index, waist/hip ratio, insulin, and homeostasis model assessment for insulin resistance and negatively with glucose/insulin ratio in the combined group (obese subjects plus controls). Visfatin levels were essentially similar in obese subjects with and without insulin resistance (p>0.05). Serum visfatin levels did not change at 60 and 120 minutes of the OGTT compared to the baseline levels (p>0.05).

CONCLUSIONS

Serum visfatin levels are elevated in obese adolescents and do not change with acute changes in glucose metabolism. Visfatin levels are related with adiposity and glucose metabolism parameters. However, the role and contribution of adiposity and glucose metabolism to the circulating visfatin levels in obese patients remain to be explored.

Visfatin and its role in obesity development

Visfatin, a product of PBEF gene, is an adipocytokine that harbours strong insulin-mimetic activity and it has been reported previously to associate with obesity. Recent reports also provide evidence that Visfatin has also important intracellular effects as it is homologous with nicotinamide phosphoribosyltransferase (NAMPT). In this review, we summarize the main documented effects of Visfatin on metabolism in humans, with special emphasis put on the pathways associated with obesity.

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.

Visfatin in overweight/obesity, type 2 diabetes mellitus, insulin resistance, metabolic syndrome and cardiovascular diseases: a meta-analysis and systemic review

There are controversies regarding the association of visfatin with overweight/obesity, type 2 diabetes mellitus, insulin resistance (IR), metabolic syndrome and cardiovascular disease in published articles. A meta-analysis was performed to identify the significance of visfatin in these diseases. We searched for relevant articles in Pubmed, Scopus and SCIE. A total of 1035 articles were surveyed and 46 articles were identified, with 14 reports reporting more than one of our investigated diseases. A total of 13 (n = 644), 19 (n = 2405), 20 (n = 2249), 5 (n = 527) and 5 (n = 851) articles/(participants) were included in each meta-analysis regarding the association of visfatin and overweight/obesity, type 2 diabetes mellitus, insulin resistance, metabolic syndrome and cardiovascular diseases, respectively. Plasma visfatin concentrations were increased in participants diagnosed with overweight/obesity, type 2 diabetes mellitus, metabolic syndrome and cardiovascular diseases, with pooled log odds ratios of 1.164 [95% confidence interval (CI): 0.348 to 1.981, p = 0.005], 1.981 (95% CI: 1.377 to 2.584, p < 0.001), 1.094 (95% CI: 0.678 to 1.511, p < 0.001), and 2.902 (95% CI: 0.924 to 4.879, p < 0.005), respectively. The circulating visfatin level was positively associated with insulin resistance, with a Fisher's z of 0.089 (95% CI: 0.013 to 0.165, p = 0.022). No single study was found to affect the overall result of each analysis by sensitivity testing. No publication bias was found by the Egger test. Our study suggests that the use of visfatin may be promising for predicting obesity, diabetes status, insulin resistance, metabolic syndrome and cardiovascular disease.

[Visfatin in obese patients, relation with cardiovascular risk factors, a cross sectional study]

BACKGROUND AND OBJECTIVE

Obesity and insulin resistance are associated with cardiovascular risk factors. The aim of the present study was to explore the relation of visfatin with insulin resistance, cardiovascular risk factors and anthropometry in obese patients without comorbidities.

PATIENTS AND METHOD

A population of 270 obese patients was analyzed in a prospective way. In all patients we performed a biochemical analysis (lipid profile, insulin, HOMA and visfatina), and a nutritional evaluation (dietary intake, conventional anthropometry and bioimpedance).

RESULTS

Patients were divided in two groups by median visfatin value (8,32 ng/ml), group I (patients with the low values, average value 7,11 (0,7) ng/ml) and group II (patients with the high values, average value 13,5 (10,1) ng/ml). Patients in the group I had higher weight, body mass index, waist circumference, and waist to hip ratio than patients in group II. Patients in group I had lower LDL-cholesterol and C reactive protein than patients in group II. Correlation analysis showed a positive correlation between visfatin levels and LDL cholesterol (r=0.194; p<0.05) and C reactive protein (r=0.266; p<0.05) and a negative corelation with weight (r=-0.162; p<0.05). In the logistic analysis with age-, sex- and dietary intake- adjusted basal visfatin concentration as a dependent variable, the next variables remained in the model; weight with an odds ratio (OR) 0,97 (IC95% 0,95-0,99), LDL cholesterol 1,012(1,010-1.023) and C reactive protein 1,15 (1.03-1.3).

CONCLUSION

LDL cholesterol and c reactive protein levels are positively correlated with visfatin levels. Weight is negatively correlated with visfatin levels, in an independent way and adjusted by age, sex and dietary intake.

Plasma visfatin and adiponectin concentrations in physically active adolescent girls: relationships with insulin sensitivity and body composition variables

The purpose of this study was to evaluate the associations of visfatin and adiponectin concentrations with insulin resistance and body composition in regularly physically active pubertal girls. In 129 girls, aged 13-15 years (pubertal stages 3-5), visfatin, adiponectin, insulin resistance measured by homeostasis model assessment (HOMA), and body composition measured by dual-energy X-ray absorptiometry were evaluated. Visfatin concentration was related to HOMA and overall adiposity (body mass index, fat mass) markers, whereas adiponectin concentration was related to overall adiposity (fat mass), central adiposity (trunk fat) and fat free mass values. These relationships remained significant (p < 0.05) after adjusting for pubertal stage. Visfatin was independently related to body mass index (beta = 0.936; p = 0.0001) and HOMA (beta = 0.444; p = 0.039) indices, whereas adiponectin was independently related to fat free mass (beta = 0.889; p = 0.003) and trunk fat (beta = -0.468; p = 0.042) values. In conclusion, visfatin could be related to insulin resistance and overall adiposity indices, whereas adiponectin was related to different body composition values in regularly physically active pubertal girls.

Nicotinamide Phosphoribosyltransferase in Human Diseases

Nicotinamide phosphoribosyltransferase (NAMPT) was first reported as a pre-B-cell colony enhancing factor in 1994 with little notice, but it has received increasing attention in recent years due to accumulating evidence indicating that NAMPT is a pleiotropic protein such as a growth factor, a cytokine, an enzyme and a visfatin. Now, NAMPT has been accepted as an official name of this protein. Because of NAMPT's multiple functions in a variety of physiological processes, their dysregulations have been implicated in the pathogenesis of a number of human diseases or conditions such as acute lung injury, aging, atherosclerosis, cancer, diabetes, rheumatoid arthritis and sepsis. This review will cover the current understanding of NAMPT's structure and functions with an emphasis on recent progress of nicotinamide phosphoribosyltransferase's pathological roles in various human diseases and conditions. Future directions on exploring its Terra incognita will be offered in the end.

Visfatin regulates genes related to lipid metabolism in porcine adipocytes

Visfatin is a visceral adipose tissue-specific adipocytokine that plays a positive role in attenuating insulin resistance by binding to the insulin receptor. Visfatin has been suggested to play a role in the regulation of lipid metabolism and inflammation; however, the mechanism remains unclear. We investigated the effects of visfatin on the regulation of gene expression in cultured porcine preadipocytes and differentiated adipocytes. In preadipocytes, the mRNA abundance of lipoprotein lipase and PPARgamma were significantly increased by visfatin or insulin treatment after 8 d (all P < 0.05). In the presence of insulin, the mRNA abundance of adipocyte fatty acid-binding protein was 24.7-fold greater than in the untreated group (P < 0.05), whereas visfatin alone had no effect on adipocyte fatty acid-binding protein mRNA abundance. Adipocyte differentiation was induced by insulin treatment for 8 d. In differentiated porcine adipocytes, exposure to insulin or visfatin for 24 h increased (P < 0.05) fatty acid synthase mRNA abundance but had no effect on the expression of sterol regulatory element binding-protein 1c mRNA. We also found a 5.8-fold upregulation of IL-6 expression in porcine adipocytes after 24 h of treatment with visfatin (P < 0.05). These results demonstrated that visfatin upregulated lipoprotein lipase expression in preadipocytes, potentially facilitating lipid uptake, and increased the gene expression of fatty acid synthase in differentiated adipocytes to potentially enhance lipogenic activity. Furthermore, visfatin can upregulate IL-6 expression in differentiated porcine adipocytes. The information presented in this study provides insights into the roles of visfatin in lipid metabolism in pigs.

The relationship between visfatin and metabolic syndrome in postmenopausal women

OBJECTIVE

The biological role and activity of visfatin, an adipokine mainly produced by visceral fat, has not been fully elucidated. The observed relationships between visfatin and metabolisyndrome are inconsistent. The purpose of this study was to illuminate the relationship between visfatin and metabolic syndrome in postmenopausal women.

METHODS

The present study included a sample of 110 postmenopausal Korean women. Subjects with cardiovascular disease or uncontrolled diabetes were excluded from the study sample. Body weight, height, blood pressure (BP), and waist and hip circumference were measured, and biochemical tests were performed.

RESULTS

The mean serum visfatin level (mean+/-SD) of subjects with metabolic syndrome was 2.74+/-1.70 ng/ml. This was significantly higher than the mean level of subjects without metabolic syndrome (p<0.01). As the number of components of metabolic syndrome increased, the concentration of serum visfatin also increased (p<0.01). Visfatin concentration was positively correlated with age (r=0.209, p<0.05), waist circumference (r=0.261, p<0.01), systolic BP (r=0.255, p<0.01), diastolic BP (r=0.252, p<0.01), fasting glucose level (r=0.278, p<0.01), fasting insulin level (r=0.313, p<0.01), HOMA-IR (r=0.345, p<0.01), total cholesterol level (r=0.213, p<0.05), triglyceride level (r=0.368, p<0.01), WBC count (r=0.352, p<0.01), and homocysteine level (r=0.196, p<0.05). Using a multiple logistic regression analysis, visfatin was found to be an independent factor associated with metabolic syndrome after an adjustment for confounding variables including age, body mass index (BMI), and HOMA-IR.

CONCLUSIONS

Serum visfatin was associated with metabolic syndrome in postmenopausal women. This suggests that visfatin may act as the underlying pathophysiological trigger for metabolic syndrome in postmenopausal women.

Body fat distribution has no effect on serum visfatin levels in healthy female subjects

Obesity is the presence of either abnormal absolute amount or relative proportion of body fat. Contrary to gluteal obesity, visceral obesity is associated with different metabolic alterations including insulin resistance (IR). A relatively new adipocytokine visfatin is shown to be expressed predominantly in visceral fat and exhibit insulin-mimicking effects in rodents. It is still unclear whether serum visfatin levels are associated with increased total or visceral fat mass in humans. The aim of our study was to investigate the relation between visfatin and obesity parameters namely body mass index (BMI) and waist circumference (WaC) and IR in healthy female subjects. Eighty one female subjects 20 years of age, having no diagnosis of glucose intolerance or diabetes, hypertension and dyslipidemia were chosen. The patients were divided into four groups according to their BMI and WaC values. Serum visfatin and HOMA-IR levels did not differ among groups. No correlation was detected between serum visfatin levels and obesity and metabolic parameters. In conclusion, we demonstrated that body fat distribution did not affect serum visfatin levels in healthy female subjects. Further studies are needed to clarify the exact factors influencing and determining serum visfatin levels and its clinical reflections.

Information-theoretic gene-gene and gene-environment interaction analysis of quantitative traits

Background

The purpose of this research was to develop a novel information theoretic method and an efficient algorithm for analyzing the gene-gene (GGI) and gene-environmental interactions (GEI) associated with quantitative traits (QT). The method is built on two information-theoretic metrics, the k-way interaction information (KWII) and phenotype-associated information (PAI). The PAI is a novel information theoretic metric that is obtained from the total information correlation (TCI) information theoretic metric by removing the contributions for inter-variable dependencies (resulting from factors such as linkage disequilibrium and common sources of environmental pollutants).

Results

The KWII and the PAI were critically evaluated and incorporated within an algorithm called CHORUS for analyzing QT. The combinations with the highest values of KWII and PAI identified each known GEI associated with the QT in the simulated data sets. The CHORUS algorithm was tested using the simulated GAW15 data set and two real GGI data sets from QTL mapping studies of high-density lipoprotein levels/atherosclerotic lesion size and ultra-violet light-induced immunosuppression. The KWII and PAI were found to have excellent sensitivity for identifying the key GEI simulated to affect the two quantitative trait variables in the GAW15 data set. In addition, both metrics showed strong concordance with the results of the two different QTL mapping data sets.

Conclusion

The KWII and PAI are promising metrics for analyzing the GEI of QT.

Genetic variant in visfatin gene promoter is associated with decreased risk of coronary artery disease in a Chinese population

BACKGROUND

Visfatin is a newly identified pro-inflammatory adipokine expressed predominantly in visceral fat. Previous studies have suggested a role for visfatin in low-grade inflammation and regulation of lipid metabolism. Most recently, a genetic polymorphism -1535C>T located in the visfatin gene promoter has been identified, and suggested to be associated with the regulation of visfatin expression, lipid levels. However, it is unclear whether this polymorphism has a linkage with CAD.

METHODS

We conducted a hospital-based case-control study with 257 CAD patients and 292 controls to examine the potential association of the Visfatin -1535C>T polymorphism with CAD.

RESULTS

The frequencies of the CC, CT, and TT genotypes in cases were significantly different from those of controls (chi2=6.223, P=0.045). Subjects with the variant genotypes (CT+TT) had a 40% decreased risk of CAD relative to CC carriers (adjusted OR=0.60, 95%CI=0.40-0.89). Furthermore, the adjusted OR of a TT genotype for CAD was 0.52 (95%CI=0.31-0.87). There was a significant association between Visfatin -1535C>T polymorphism and triglyceride levels in both CAD patients and controls (P=0.003, 0.018, respectively). In stratified analyses, the T allele was significantly associated with reduced risk of CAD in males, subjects with age <59years, and non-smokers. Moreover, a borderline statistical significance (P=0.058 for trend) was observed between the variant genotypes and severity of CAD.

CONCLUSION

Our results suggested that Visfatin -1535C>T polymorphism might be associated with reduced risk of CAD in a Chinese population.

Serum visfatin in Asian women with polycystic ovary syndrome

OBJECTIVE

To determine serum visfatin levels in Asian polycystic ovary syndrome (PCOS) women and its correlations with various parameters.

STUDY DESIGN

Case-control study.

SETTING

University hospital.

SUBJECTS

Eighty women were enrolled in this study. Of these, 40 women were PCOS and 40 age-matched subjects with regular menstrual cycles were controls.

INTERVENTION

Seventy-five gram oral glucose tolerance tests were performed in all women. Fasting venous blood samples for serum visfatin, insulin and androgen levels were obtained both from the PCOS and the control women.

MAIN OUTCOME MEASURES

Serum concentrations of visfatin, fasting insulin (FI), fasting glucose, 2-h post-load glucose (2hPG), homeostasis model assessment insulin resistance, homeostasis model assessment beta cell function, total testosterone, free testosterone, androstenedione and dehydroepiandrosterone sulfate were measured in both groups.

RESULTS

Women with PCOS had significantly higher serum visfatin levels than the healthy controls [100.39 +/- 41.90 vs. 45.09 +/- 28.24 mg/ml, p < 0.01]. PCOS women also had significantly higher concentrations of all androgens (p < 0.01). Insulin resistance seemed to be greater in the PCOS than the control groups, but did not reach a statistically significant level. In the PCOS group, serum visfatin levels were positively correlated with 2hPG, and systolic blood pressure and diastolic blood pressure. Serum visfatin levels were negatively associated with FI (r = -0.80, p = 0.03) and positively associated with systolic and diastolic blood pressure (r = 0.77, p = 0.04, r = 0.79, p = 0.03, respectively) in the sub-group of PCOS women with abnormal glucose tolerance (AGT).

CONCLUSIONS

Asian PCOS women had significantly higher serum visfatin levels than age-matched healthy controls. Their levels were significantly correlated with 2hPG and blood pressure in PCOS women, and with FI and blood pressure in PCOS women with AGT.

Plasma visfatin levels in preeclamptic and normal pregnancies

OBJECTIVE

Increasing evidences support the participation of adipokines in the pathogenesis of preeclampsia (PE). Visfatin is a novel adipokine secreted by fat tissue and macrophages and is involved in the regulation of glucose homeostasis. Our aim is to investigate visfatin levels in women with PE, women with the third trimester of normal pregnancy and healthy non-pregnant women.

PATIENTS AND METHODS

We included 32 preeclamptic patients who received antenatal and obstetric care at Perinatology Clinic. A total of 32 pregnant women with normal ongoing pregnancies and 32 non-pregnant women were taken as the control groups. Plasma levels of visfatin were quantified by ELISA.

RESULTS

Plasma levels of visfatin were 63.8 +/- 4.9 ng/ml in women with PE, 43.6 +/- 7.8 ng/ml in pregnant control and 31.6 +/- 4.2 ng/ml in the non-pregnant control, respectively (P < 0.001). Visfatin level was significantly higher in PE compared with non-pregnant control (P < 0.001) and pregnant control (P < 0.001); also, plasma level of visfatin was significantly higher in severe PE (75.3 +/- 4.6 ng/ml) than mild PE (41.8 +/- 5.2 ng/ml) (P < 0.001).

CONCLUSION

The results of the present study indicate that women with PE had significantly increased visfatin concentrations in the third trimester. Furthermore, visfatin levels were significantly higher in severe PE group.

Plasma visfatin concentrations after a lifestyle intervention were directly associated with inflammatory markers

BACKGROUND AND AIMS

The biological activity and regulation of the novel adipokine visfatin are still largely unknown. Our aim was to evaluate if visfatin plasma concentrations may be influenced by a lifestyle intervention.

METHODS AND RESULTS

Out of 335 dysmetabolic patients from a population-based cohort, randomized to receive a lifestyle intervention program (intervention group) or family physician usual care (controls), 20 patients per group were randomly selected for plasma visfatin determination. The before-after variation (Delta) in visfatin concentration at 1-year from randomization, and the correlations between (Delta)visfatin and intervention-induced changes in waist circumference, fasting glucose, markers of inflammation, and oxidative stress were evaluated. The intervention group showed a significant improvement in waist circumference, and many metabolic/inflammatory variables, while the controls worsened. Visfatin concentrations slightly decreased in the former and significantly increased in the controls ((Delta)visfatin=-2.4 vs 66.0 ng/ml, p<0.001). In robust regression models, the following variables resulted associated with (Delta)visfatin: (Delta)waist circumference, (Delta)fasting glucose, (Delta)hs-CRP (high-sensitivity C-reactive protein) and (Delta)TNFalpha (tumor necrosis factor-alpha). Significant effects on (Delta)visfatin of (Delta)TNFalpha (beta=16.8; 6.1-25.6; p=0.003) and, modified by group, of (Delta)hs-CRP (beta=29.8; 95% CI 15.4-44.2; p<0.001 and beta=4.2; 2.9-5.5; p<0.001 in the control and intervention group, respectively) were detected. By controlling for (Delta)waist, the effects of (Delta)TNFalpha and of (Delta)hs-CRP on (Delta)visfatin by group did not change, while (Delta)waist was no longer associated. The association between (Delta)visfatin and (Delta)glucose was no longer significant, after adjusting for (Delta)hs-CRP.

CONCLUSION

Visfatin values increased with waist circumference and were associated with variations of inflammatory markers, suggesting participation in inflammatory mechanisms.

Maternal visfatin concentration in normal pregnancy

OBJECTIVE

Adipose tissue has now emerged as a powerful endocrine organ via the production of adipokines. Visfatin, a novel adipokine with diabetogenic and immuno-modulatory properties has been implicated in the pathophysiology of insulin resistance in patients with obesity and Type-2 diabetes mellitus. The aim of this study was to determine whether there are changes in the maternal plasma concentration of visfatin with advancing gestation and as a function of maternal weight.

STUDY DESIGN

In this cross-sectional study, maternal plasma concentrations of visfatin were determined in normal weight and overweight/obese pregnant women in the following gestational age groups: 1) 11-14 weeks (n=52); 2) 19-26 weeks (n=68); 3) 27-34 weeks (n=93); and 4) >37 weeks (n=60). Visfatin concentrations were determined by ELISA. Non parametric statistics were used for analysis.

RESULTS

1) The median maternal plasma visfatin concentration was higher in pregnant women between 19-26 weeks of gestation than that of those between 11-14 weeks of gestation (P<0.01) and those between 27-34 weeks of gestation (P<0.01); 2) among normal weight pregnant women, the median plasma visfatin concentrations of women between 19-26 weeks of gestation was higher than that of those between 11-14 weeks (P<0.01) and those between 27-34 weeks (P<0.01); and 3) among overweight/obese patients, the median maternal visfatin concentration was similar between the different gestational age groups.

CONCLUSION

The median maternal plasma concentration of visfatin peaks between 19-26 and has a nadir between 27-34 weeks of gestation. Normal and overweight/obese pregnant women differed in the pattern of changes in circulating visfatin concentrations as a function of gestational age.

Effect of pioglitazone on visfatin expression in 3T3-L1 adipocytes and SD rats

OBJECTIVE

To investigate the effect of pioglitazone on visfatin expression.

METHODS

We studied the effect of pioglitazone on visfatin expression in 3T3-L1 adipocytes and serum concentrations and tissue expression of visfatin in normal Sprague-Dawley rats and rats with insulin resistance induced by high-fat diet (HF). Metabolic and anatomical parameters of the rats were also performed.

RESULTS

In 3T3-L1 adipocytes, visfatin expression increased during the differentiation and it was not regulated by pioglitazone. In the rats, 12 weeks of HF feeding induced obesity and increased fast blood glucose (FBG), serum insulin and circulating visfatin. Pioglitazone treatment ameliorated insulin resistance with concomitant reduction in serum visfatin, free fatty acid, and triglyceride (TG) of the rats fed HF. Compared with subcutaneous adipose tissue and muscle, visfatin protein expression was much higher in visceral adipose tissue on both diets (p < 0.05 for all). Visfatin expression decreased in visceral adipose tissue but not subcutaneous adipose tissue or muscle after pioglitazone treatment in HF-fed rats. Visfatin expression in the rats fed chow diet was not affected by pioglitazone. Additionally, we demonstrated that serum visfatin was positively correlated with visceral adipose tissue weight, visfatin in visceral adipose tissue, TG and FBG (p < 0.05 for all).

CONCLUSION

Visfatin is preferentially produced by visceral fat and peroxisome proliferator-activated receptor-gamma agonist ameliorates the development of insulin resistance in HF-fed rats with a major decrease in visfatin expression, the effect of pioglitazone on visfatin in HF-fed rats is dependent on glucose and lipid metabolism in the animals.

Ethnic difference in inter-East Asian subjects with normal glucose tolerance and impaired glucose regulation: a systematic review and meta-analysis focusing on fasting serum insulin

AIMS

To investigate ethnic difference by focusing on fasting serum insulin (FSI) in inter-East Asian subjects with normal glucose tolerance (NGT) and impaired glucose regulation (IGR).

METHODS

Data sources included MEDLINE and EMBASE between 2001 and 2007. We conducted a search for articles containing mean or geometric mean values of FSI in East Asian subjects with NGT, IGR, or type 2 diabetes (T2DM). The Monte Carlo method was used for simulation of the mean and standard deviation of individual measures in each ethnic group; calculation of the median ratio and 95% confidence interval of individual measures between ethnic groups.

RESULTS

Twenty-two articles fully met our pre-determined criteria and were included in the meta-analysis. Results of the meta-analysis revealed that FSI level is significantly lower in Japanese subjects with NGT, IGR, or T2DM than in Korean and Chinese subjects.

CONCLUSIONS

Ethnic difference in FSI level between East Asians was observed in not only T2DM patients but also subjects with NGT or IGR. The lower FSI level in Japanese subjects was accompanied by lower triglyceride level. These results suggest that ethnic difference in dietary habit was one of the most influential factors for the ethnic difference in FSI.

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

OBJECTIVE

Visfatin is an adipokine with revealing roles in inflammatory mechanisms but its implication in inflammation related to excessive adiposity/obesity is not studied yet. Our aim was to investigate the relations of visfatin with inflammation markers and body mass index (BMI) in the peripheral blood mononuclear cells (PBMCs), a type of cells closely related to inflammatory mechanisms.

DESIGN

Cross-sectional study, quantification of visfatin, TNF-alpha, IL-6 mRNA in PBMCs.

PATIENTS

Eighty-three supposed healthy individuals from the STANISLAS cohort, belonging in three BMI categories: BMI < 25 kg/m(2) (lean), 25 kg/m(2) <or= BMI < 30 kg/m(2) (overweight) or BMI >or= 30 kg/m(2) (obese).

MEASUREMENTS

We measured visfatin gene expression (by real-time quantitative PCR), in relation to gene expression of the pro-inflammatory cytokines TNF-alpha, IL-6 in PBMCs and to anthropometric parameters (weight, BMI, waist : hip ratio), blood pressure, lipid profile, glucose and inflammatory markers (C-reactive protein, lymphocyte count).

RESULTS

Visfatin expression in PBMCs was significantly associated with BMI in a negative way (r = -0.21, P = 0.05). Global anova analysis test for lean and over-weight/obese individuals showed a negative significant association between visfatin expression in PBMCs and BMI both for men and women (P = 0.05 and P = 0.01, respectively) and these associations remained significant after separating subjects in three groups (lean, overweight, obese) for men and women (P = 0.02 and P = 0.05, respectively). Correlation analysis between levels of expression of visfatin and TNF-alpha showed a significant positive linear association (r(2) = 0.27, P < 0.0001).

CONCLUSION

These findings reveal a probable new role of visfatin in inflammation reflected in PBMCs, in the context of obesity.

The -1535 promoter variant of the visfatin gene is associated with serum triglyceride and HDL-cholesterol levels in Japanese subjects

Visfatin is a novel adipocytokine that is expressed by the visceral fat cells. We investigated the role of genetic variation in the visfatin gene in the pathophysiology of type 2 diabetes and clinical variables in Japanese subjects. The 11 exons, and the promoter region of the visfatin gene were screened for single nucleotide polymorphisms (SNPs) by PCR-direct sequencing. We found SNPs in the promoter region (SNP - 1535T>C), exon 2 (SNP + 131C>G, Thr44Arg), and exon 7 (SNP + 903G>A). The allele and genotype frequencies of these SNPs showed no significant differences between 200-448 diabetic and 200-333 control subjects. However, the -1535T/T genotype was associated with lower serum triglyceride levels (T/T vs. T/C + C/C (p = 0.015) and T/T vs. C/C (p = 0.043)) and higher HDL-cholesterol levels (T/T vs. C/C, p = 0.0496) in the nondiabetic subjects. Reporter gene assay of 3T3-L1 adipocytes revealed that the promoter activity of -1535T and -1535C was similar, suggesting that the observed association may reflect linkage disequilibrium between -1535T>C and causative variations of the visfatin gene.

Plasma visfatin concentrations in severely obese subjects are increased after intestinal bypass

OBJECTIVE

Visfatin has shown to be increased in obesity and in type 2 diabetes. The aim of this study was to determine the change in plasma visfatin in severely obese (SO) persons after weight loss following bariatric surgery in relation to glucose concentration.

RESEARCH METHODS AND PROCEDURES

Visfatin and leptin were studied in 53 SO persons (BMI, 54.4 +/- 6.8 kg/m(2)) before and 7 months after bariatric surgery and in 28 healthy persons (BMI, 26.8 +/- 3.8 kg/m(2)). All of the patients underwent bariatric surgery with biliopancreatic diversion or gastric bypass.

RESULTS

The pre-surgery levels of visfatin in the SO group were greater than in the control group (55.9 +/- 39.9 vs. 42.9 +/- 16.6 ng/mL, p = 0.024). This increase was significant in the SO group with impaired fasting glucose (63.4 +/- 36.6 ng/mL) and diabetes (60.0 +/- 46.0 ng/mL). SO patients with normal fasting glucose had similar levels of visfatin to the controls. Seven months after surgery, visfatin levels were significantly increased (84.8 +/- 32.8 ng/mL, p < 0.001). This increase was independent of the pre-surgical glucose levels. The type of bariatric surgery had no influence on visfatin levels. Post-surgical visfatin was significantly correlated with the post-surgery plasma concentrations of leptin (r = 0.39, p = 0.014).

DISCUSSION

Plasma levels of visfatin in the SO group were increased but only when accompanied by high glucose levels, even in the range of impaired fasting glucose. Bariatric surgery causes an increase in visfatin, which is correlated mainly with the changes produced in the leptin concentration.

The relationship between visfatin levels and anthropometric and metabolic parameters: association with cholesterol levels in women

Adipose tissue has recently been identified as an endocrine organ. Visfatin is a novel adipocytokine predominantly secreted from visceral adipocytes. Visceral obesity is an important component of metabolic syndrome; however, the relationship between visfatin levels and metabolic syndrome is not clear. The purpose of this study was to explore the association between visfatin levels and anthropometry and parameters of metabolic syndrome. Anthropometric measurements included height, weight, body mass index, waist and hip circumferences, waist-to-hip ratio, and blood pressure. Metabolic parameters including fasting serum visfatin, fasting serum insulin and fasting plasma glucose, lipid profiles, and uric acid levels were measured. Data of 500 subjects (244 men and 256 women) were used for the analysis. There was no significant difference in serum visfatin levels between male and female subjects. Visfatin correlated negatively with body mass index (beta = -.011, P = .025) in male subjects; however, visfatin did not correlate with any other anthropometric or any metabolic parameters in male subjects. There was no correlation between visfatin levels and any anthropometric parameters in female subjects; however, it did correlate positively with high-density lipoprotein cholesterol levels (beta = .126, P = .006) and correlate negatively with low-density lipoprotein cholesterol levels (beta = -.039, P = .010) in female subjects. In conclusion, visfatin is not related to most anthropometric parameters and most parameters of metabolic syndrome. It may play a role in cholesterol homeostasis in women.