Expression of visfatin in gingival crevicular fluid and gingival tissues in different periodontal conditions: a cross-sectional study

BACKGROUND

Studies have shown that visfatin is an inflammatory factor closely related to periodontitis. We examined the levels of visfatin in gingival crevicular fluid (GCF) and gingival tissues under different periodontal conditions, in order to provide more theoretical basis for exploring the role of visfatin in the pathogenesis of periodontitis.

METHODS

We enrolled 87 subjects, with 43 in the chronic periodontitis (CP) group, 21 in the chronic gingivitis (CG) group, and 23 in the periodontal health (PH) group. Periodontal indexes (PD, AL, PLI, and BI) were recorded. GCF samples were collected for visfatin quantification, and gingival tissues were assessed via immunohistochemical staining.

RESULTS

Visfatin levels in GCF decreased sequentially from CP to CG and PH groups, with statistically significant differences (P < 0.05). The CP group exhibited the highest visfatin levels, while the PH group had the lowest. Gingival tissues showed a similar trend, with significant differences between groups (P < 0.001). Periodontal indexes were positively correlated with visfatin levels in both GCF and gingival tissues (P < 0.001). A strong positive correlation was observed between visfatin levels in GCF and gingival tissues (rs = 0.772, P < 0.001).

CONCLUSION

Greater periodontal destruction corresponded to higher visfatin levels in GCF and gingival tissues, indicating their potential collaboration in damaging periodontal tissues. Visfatin emerges as a promising biomarker for periodontitis and may play a role in its pathogenesis.

Association between visfatin and periodontitis: a systematic review and meta-analysis

Background

Periodontitis is a chronic inflammatory disease caused by bacterial infection in the periodontal support tissue. Visfatin, a hormone secreted mainly by adipocytes and macrophages, plays an important role in immune regulation and defense. Although studies have indicated that patients with periodontitis have significantly high serum and gingival crevicular fluid levels of visfatin, the relationship between this adipocytokine and periodontal disease remains unclear.

Aim

The aim of this study was to systematically evaluate the association between visfatin levels and periodontitis.

Methods

The PubMed, Web of Science, ScienceDirect, EBSCO, and Wiley Online Library databases were searched for potential studies, using "periodontitis" and "visfatin" as the keywords in the title and abstract search fields. Standardized mean difference (SMD) values with corresponding 95% confidence intervals (CIs) were determined from the results of this meta-analysis.

Results

In total, 22 articles involving 456 patients with periodontitis and 394 healthy individuals (controls) were included in the meta-analysis. Visfatin levels were significantly higher in the patients with periodontitis than in the healthy individuals (SMD: 3.82, 95% CI [3.01-4.63]). Moreover, the visfatin levels were significantly lowered after periodontitis treatment (SMD: -2.29, 95% CI [-3.33 to -1.26]).

Conclusion

This first-ever meta-analysis comparing visfatin levels between patients with periodontitis and healthy individuals suggests that this adipocytokine can be a diagnostic and therapeutic biomarker for periodontal disease.

Periodontitis is associated with the increased levels of visfatin: a meta-analysis

OBJECTIVE

Periodontitis is a common inflammatory disease associated with systemic factors. Visfatin is a pleiotropic adipokine that exerts metabolic and immune functions. Studies have shown visfatin played roles in the development of periodontitis. The present study aims to compare the levels of visfatin in body fluids including serum, saliva, and gingival crevicular fluid (GCF) between periodontitis patients and healthy individuals, and to elucidate the alteration of visfatin levels after periodontal treatments.

MATERIALS AND METHODS

The database searched included Pubmed, Embase, Web of Science, and Cochrane Library. According to the Eligibility criteria, the records were screened and the eligible studies were included. The methodological qualities of the included case-controlled studies were assessed according to the Newcastle-Ottawa scale (NOS). The Methodological Index for Nonrandomized Studies (MINORS) was applied for assessing the qualities of the included clinical trials. The statistical analyses were processed using STATA 15.0.

RESULTS

Twenty-three studies were included in the statistical analyses. The meta-analysis showed significantly elevated visfatin levels of GCF, serum, and saliva in the periodontitis population compared with the controls (GCF: SMD = 5.201, 95% CI: 3.886-6.516, Z = 7.75, P < 0.05; Serum: SMD = 7.417, 95% CI: 3.068-11.767, Z = 3.34, P = P < 0.05; Saliva: SMD = 2.683, 95% CI: 1.202-4.163, Z = 3.34, P < 0.05). Visfatin levels of saliva serum and GCF were significantly decreased after periodontal treatment. (Saliva: SMD = -1.338, 95% CI: -2.289-0.487, Z = 39.77, P < 0.05; Serum: SMD = -2.890, 95% CI: -5.300-0.480, Z = 2.35, P < 0.05; GCF: SMD = -6.075, 95% CI: -11.032-1.117, Z = 2.40, P = 0.016; I 2 = 95.9%, P < 0.05).

CONCLUSIONS

Periodontitis elevated the visfatin levels in GCF, serum, and saliva. Additionally, GCF, serum, and saliva visfatin levels could be reduced after periodontal treatment.

Nicotinamide phosphoribosyltransferase expression and clinical outcome of resected stage I/II pancreatic ductal adenocarcinoma

BACKGROUND

Nicotinamide phosphoribosyltransferase (NAMPT) plays a key role in the biosynthesis of nicotinamide adenine dinucleotide (NAD+), which is a vital cofactor in redox reactions and a substrate for NAD+ consuming enzymes including CD38, PARPs and sirtuins. NAMPT over-expression has been shown in various cancers and its inhibition decreases cancer cell growth, making it an attractive therapeutic target. Here we examine the NAMPT expression in a large cohort of resected stage I/II pancreatic ductal adenocarcinomas (PDAs) and correlate its expression with clinical outcomes and pathologic features.

METHODS

A retrospective review of patients with PDAs was conducted at a single institution. Tissue microarrays (TMAs) containing primary PDAs and their metastatic lymph nodes (mLNs) were constructed and stained for NAMPT expression. Each TMA core was evaluated for staining intensity of cancer cells (0 = no staining, 1+ = weak, 2+ = moderate, 3+ = strong) and a mean score was calculated for each case with at least two evaluable cores. NAMPT expression was correlated with clinicopathological variables using chi-squared or Fisher's exact test, and t-tests for categorical and continuous variables, respectively. Survival probabilities were estimated and plotted using the Kaplan-Meier method. Cox proportional hazards regression was used to assess the effects of NAMPT staining values on recurrence-free survival (RFS) and overall survival (OS). This study was conducted under an approved IRB protocol.

RESULTS

173 primary PDAs had at least 2 TMA cores with identifiable cancer cells. The mean IHC score was 0.55 (range: 0 to 2.33). The mean IHC score of mLNs was 0.39 (range: 0-2), which was not significantly different from their primary tumors (mean IHC score = 0.47, P = 0.38). Sixty-four percent (111/173) of PDAs were positive for NAMPT staining. Stage II tumors were more likely to be positive (68% of 151 vs 41% of 22; P = 0.01). Non-obese non-diabetic patients were more likely to have NAMPT+ tumors (43.7% vs. 27.9%, P = 0.04). While RFS and OS were not statistically different between NAMPT+ vs. NAMPT- PDAs, patients with NAMPT- tumors tended to have a longer median OS (26.0 vs. 20.4 months, P = 0.34).

CONCLUSION

NAMPT expression was detected in 64% of stage I/II PDAs and up to 72% in non-obese non-diabetic patients. Frequency of NAMPT expression correlated with pathological stage, consistent with published literature regarding its role in cancer progression. While RFS and OS were not statistically significantly different, patients with NAMPT+ PDAs tended to have a shorter survival. Thus, NAMPT inhibition may prove beneficial in clinical trials.

Expression of n-MYC, NAMPT and SIRT1 in Basal Cell Carcinomas and their Cells of Origin

Deregulated Hedgehog signalling is a driver of basal cell carcinomas. One effector of the Hedgehog pathway is n-MYC. c/n-MYC proteins, NAMPT and DBC1 are linked to SIRT1 in a positive feedback loop that may contribute to tumorigenesis of basal cell carcinoma. In 5 basal cell carcinoma types immunohistochemistry revealed n-MYC, NAMPT and SIRT1 expression. DBC1 was homogenously expressed in all epithelial cells. NAMPT, SIRT1 and c-MYC were expressed in the stratum basale of human and murine skin. In hair follicles NAMPT and SIRT1 were expressed together with c-MYC and n-MYC, except for the matrix, where n-MYC was strongly positive, but c-MYC expression was absent. Therefore, a common pathway connecting n-MYC, NAMPT and SIRT1 may be active in basal cell carcinomas and in their cells of origin. This pathway may contribute to the development of basal cell carcinomas. Targeting factors in the feedback loop may offer novel therapeutic options.

Novel bone metabolism-associated hormones: the importance of the pre-analytical phase for understanding their physiological roles

The endocrine function of bone is now a recognized feature of this tissue. Bone-derived hormones that modulate whole-body homeostasis, are being discovered as for the effects on bone of novel and classic hormones produced by other tissues become known. Often, however, the data regarding these last generation bone-derived or bone-targeting hormones do not give about a clear picture of their physiological roles or concentration ranges. A certain degree of uncertainty could stem from differences in the pre-analytical management of biological samples. The pre-analytical phase comprises a series of decisions and actions (i.e., choice of sample matrix, methods of collection, transportation, treatment and storage) preceding analysis. Errors arising in this phase will inevitably be carried over to the analytical phase where they can reduce the measurement accuracy, ultimately, leading discrepant results. While the pre-analytical phase is all important, in routine laboratory medicine, it is often not given due consideration in research and clinical trials. This is particularly true for novel molecules, such as the hormones regulating the endocrine function of bone. In this review we discuss the importance of the pre-analytical variables affecting the measurement of last generation bone-associated hormones and describe their, often debated and rarely clear physiological roles.

Decreased immunoreactivity of visfatin in the pancreas and liver of rats with renovascular hypertension

Hypertension is one of the major endocrine and metabolic disorders, in which visfatin plays a significant role. The objective of this study was to evaluate the immunoreactivity of visfatin in pancreas and liver of “two kidney, one clip” (2K1C) renovascular hypertension model in rats. The studies were carried out on the pancreas and liver of rats. After a 6-week period of the renal artery clipping procedure, 2K1C rats developed a stable hypertension. Paraffin sections were stained with hematoxylin and eosin (for general histological examination) and processed for immunolocalization of visfatin. The intensity of immunohistochemical reaction was measured using Nikon NIS-Elements Advanced Research software. The hypertension significantly weakened the immunohistochemical reaction exhibiting visfatin in the pancreas and liver of hypertensive rats, compared to control animals. The changes induced by hypertension in the visfatin-containing cells in the pancreas and liver of the rats are discussed and needs further study.

Simultaneous Analysis of Major Coenzymes of Cellular Redox Reactions and Energy Using ex Vivo (1)H NMR Spectroscopy

Coenzymes of cellular redox reactions and cellular energy mediate biochemical reactions fundamental to the functioning of all living cells. Despite their immense interest, no simple method exists to gain insights into their cellular concentrations in a single step. We show that a simple (1)H NMR experiment can simultaneously measure oxidized and reduced forms of nicotinamide adenine dinucleotide (NAD(+) and NADH), oxidized and reduced forms of nicotinamide adenine dinucleotide phosphate (NADP(+) and NADPH), and adenosine triphosphate (ATP) and its precursors, adenosine diphosphate (ADP) and adenosine monophosphate (AMP), using mouse heart, kidney, brain, liver, and skeletal muscle tissue extracts as examples. Combining 1D/2D NMR experiments, chemical shift libraries, and authentic compound data, reliable peak identities for these coenzymes have been established. To assess this methodology, cardiac NADH and NAD(+) ratios/pool sizes were measured using mouse models with a cardiac-specific knockout of the mitochondrial Complex I Ndufs4 gene (cKO) and cardiac-specific overexpression of nicotinamide phosphoribosyltransferase (cNAMPT) as examples. Sensitivity of NAD(+) and NADH to cKO or cNAMPT was observed, as anticipated. Time-dependent investigations showed that the levels of NADH and NADPH diminish by up to ∼50% within 24 h; concomitantly, NAD(+) and NADP(+) increase proportionately; however, degassing the sample and flushing the sample tubes with helium gas halted such changes. The analysis protocol along with the annotated characteristic fingerprints for each coenzyme is provided for easy identification and absolute quantification using a single internal reference for routine use. The ability to visualize the ubiquitous coenzymes fundamental to cellular functions, simultaneously and reliably, offers a new avenue to interrogate the mechanistic details of cellular function in health and disease.

Increased visfatin levels are associated with higher disease activity in anti-Jo-1-positive myositis patients

OBJECTIVES

The aim of this study was to evaluate serum levels of visfatin in anti-Jo-1-positive myositis patients, its expression in muscle tissue and to investigate potential relationships between visfatin, B-cell activating factor of the TNF family (BAFF), disease activity and anti-Jo-1 autoantibody levels.

METHODS

Serum levels of visfatin and BAFF were measured in 38 anti-Jo-1 positive myositis patients and 35 healthy subjects. Disease activity was evaluated by myositis disease activity assessment tool (MYOACT) using visual analogue scales (VAS) and by serum muscle enzymes. Visfatin expression was evaluated by immunohistochemistry in muscle tissue of myositis patients (n=10) and compared with non-inflammatory control muscle tissue samples from patients with myasthenia gravis (n=5).

RESULTS

Serum visfatin and BAFF levels were significantly higher in myositis patients compared to healthy subjects and were associated with clinical muscle activity assessed by VAS. Only serum BAFF levels, but not visfatin levels, positively correlated with muscle enzyme concentrations and anti-Jo1 antibody levels. There was a positive correlation between visfatin and BAFF serum levels in myositis patients but a negative correlation was observed in healthy subjects. Visfatin expression was up-regulated in endomysial and perimysial inflammatory infiltrates of muscle tissue from myositis patients.

CONCLUSIONS

Up-regulation of visfatin in myositis muscle tissue and an association between increased visfatin levels and muscle disease activity evaluated by MYOACT in anti-Jo-1 positive myositis patients could support possible role of visfatin in the pathogenesis of myositis.

Visfatin as a novel mediator released by inflamed human endothelial cells

Background

Visfatin is a multifaceted adipokine whose circulating levels are enhanced in different metabolic diseases. Extracellular visfatin can exert various deleterious effects on vascular cells, including inflammation and proliferation. Limited evidence exists, however, on the capacity of human vascular cells to synthesize and release visfatin by themselves, under basal or pro-inflammatory conditions.

Methods and Results

Intracellular visfatin was detected by Western blot in non-stimulated human umbilical vein endothelial cells (HUVEC). However, exposing HUVEC for 18 h to a series of pro-inflammatory stimulus, such as interleukin (IL)-1β (1 to 10 ng/mL), tumor necrosis factor-α (1 to 10 ng/mL) or angiotensin II (10 pmol/L to 1 μmol/L) markedly enhanced intracellular visfatin content. Using IL-1β (10 ng/mL; 18 h), it was determined that the increase in intracellular visfatin, which was paralleled by enhanced visfatin mRNA levels, relied on a signalling mechanism involving both nuclear factor-κB and poly (ADP ribose) polymerase-1 activation. Moreover, IL-1β modified the sub-cellular localization of visfatin; while in non-stimulated HUVEC immunoreactive visfatin predominantly showed an intra-nuclear granular pattern, in IL-1β-inflamed cells an extra-nuclear filamentous staining, co-localising with F-actin fibers and suggesting a secretory pattern, was mainly found. Indeed, IL-1β promoted visfatin secretion, as determined by both ELISA and immunocytochemistry.

Conclusions

Human endothelial cells synthesize and release visfatin, particularly in response to inflammation. We suggest that the inflamed endothelium can be a source of visfatin, which arises as a local inflammatory mediator and a potential therapeutic target to interfere with vascular inflammation.

The influence of intensive physical training on salivary adipokine levels in Elite Rhythmic Gymnasts

Exercise challenges homeostasis and establishes a new dynamic equilibrium. Elite Rhythmic Gymnasts (RG's) begin exercise at an early age, undergo physical and psychological stress, and adopt negative energy balance to retain a lean physique. The aim of the present study was to evaluate the effect of negative energy balance, acute and chronic exercise on salivary adiponectin, resistin and visfatin levels and their interaction with salivary cortisol, and insulin levels in elite RG's. This study is unique in character, as all variables were assessed on the field of competition. The study included 51 elite RG's participating in "Kalamata 2010 World Cup" in Kalamata, Greece on April 2010. Twenty-seven healthy age-matched girls were used as controls. Anthropometric values were assessed; baseline and post exercise salivary cortisol, insulin, adiponectin, resistin, and visfatin levels were measured. Comparisons regarding hormonal features between RG's and controls were adjusted for BMI and body fat percentage. Salivary adiponectin levels were higher (p<0.05) and visfatin lower (p=0.094) in RG's compared with controls, while no significant changes were observed regarding salivary cortisol, insulin, and resistin levels. In elite RG's acute intensive anaerobic exercise led to increased salivary insulin levels (p<0.001), reduced salivary adiponectin (p<0.001) and visfatin levels (p<0.05), and no changes in salivary resistin levels. Moreover, diurnal variation of salivary cortisol was lost. In elite RG's salivary adiponectin is upregulated and salivary visfatin is downregulated after chronic intensive exercise and negative energy balance, while both salivary adiponectin and visfatin levels are suppressed after short term intensive anaerobic exercise.

Clinical analysis of systemic and adipose tissue levels of selected hormones/adipokines and stromal-derived factor-1

Recent studies demonstrated that selected hormones/adipokines may be involved into the regulation of bone metabolism and bone marrow-derived hematopoietic stem/progenitor cells (HSPCs) mobilization in humans. Interestingly, in obese individuals significantly higher numbers of spontaneously circulating stem cells are also observed. Therefore in this study we comprehensively examined plasma and AT (subcutaneous and visceral/omental) levels of hormones/adipokines involved in HSPCs mobilization in lean, overweight and obese individuals as well as verified their potential associations with concentrations of HSPCs chemoattractant, stromal-derived factor-1 (SDF-1). Blood and AT samples (35 subcutaneous and 35 omental) were obtained from individuals undergoing elective surgery. Plasma and AT-derived interstitial fluid levels of resistin, visfatin, osteocalcin and SDF-1 were measured using ELISA. In our study obese patients had almost significantly (P&#60;0.06) higher plasma visfatin and resistin levels as well as lower osteocalcin concentrations (P&#60;0.04) than lean individuals. Osteocalcin and resistin concentrations were strongly associated with levels of SDF-1 and metalloproteinases (MMP 2 and 9). AT levels of all examined substances were significantly lower than the corresponding levels in the plasma (in all cases at least P&#60;0.05), and depot-specific differences in the concentrations of these factors were found only in terms of osteocalcin and SDF-1. In addition, subcutaneous and visceral/omental concentrations of osteocalcin and visfatin, but not of resistin, were associated with values of such parameters as age, body mass or adiposity indexes (BMI and BAI, respectively) and/or waist-to-hip ratio (WHR). In summary, our study showed that in obese individuals the biochemical constellation of adipokines/hormones involved in the process of HSPCs mobilization resembles this observed during pharmacological HSPCs mobilization. Moreover, our study offers further indirect translational evidence for existence of a biochemical cross-talk between bone and AT metabolism (so called - bone-fat- axis) in humans.

Measurement of salivary resistin, visfatin and adiponectin levels

Hormonal determination in saliva offers several advantages. Peptides enter the salivary glands either by active transport mechanisms or are expressed and secreted by the salivary glands themselves. The collection of saliva is a noninvasive, easily repeatable and less stressful technique than blood withdrawal. The purpose of the present study was to introduce a method for measuring salivary resistin, visfatin and adiponectin levels and to evaluate their associations with serum levels. Resistin, visfatin and adiponectin levels were measured in serum and saliva of 50 healthy adult volunteers (17 male and 33 female) using commercial enzyme immunoassay kits for serum with minor modifications. The present study documented the determination of resistin and adiponectin levels in saliva and the significant correlation of salivary levels with serum levels (r=0.441, p<0.01 and r=0.347, p<0.05, respectively). Moreover, the identification of visfatin in saliva was achieved, but no significant correlation with serum visfatin levels was observed. To our knowledge, this is the first study to report the determination of resistin and visfatin in saliva and the significant correlation of salivary resistin with serum levels, while it confirmed the significant association between salivary and serum adiponectin. The introduction of salivary determinations of adipokines could contribute to the elucidation of the physiology and the role of the specific adipokines in various clinical conditions (obesity, insulin resistance, inflammation, reproduction, energy imbalance and stress response).

Relation of adiponectin, visfatin and bone mineral density in patients with metabolic syndrome

BACKGROUND

Adipose tissue has been suggested to influence bone density and metabolism through the effect of some adipokines. However, whether adiponectin and visfatin may correlate with bone metabolism is still unclear.

AIM

The aim of this study was to investigate the relationship of adiponectin and visfatin with bone density in patients with metabolic syndrome (MS).

SUBJECTS

We enroled 72 consecutive patients with MS (25 males, 47 females; mean age 58.14±11 yr) and 40 control subjects.

METHODS

Plasma adiponectin and visfatin levels were measured. Bone mineral density (BMD) was assessed by dual energy X-ray absorptiometry (DXA) at the level of lumbar spine L2-L4 (BMD L2-L4) and femoral neck (BMD-Fn).

RESULTS

MS patients had higher plasma visfatin and lower adiponectin levels than controls, (p<0.01 for both). Adiponectin was negatively correlated with BMD-Fn and BMD L2-L4 (r=-0.20, r=-0.24, respectively; p<0.05 for both) whereas plasma visfatin levels were positively correlated to BMD L2-L4 only in men (r=0.44; p<0.05).

CONCLUSIONS

Our study shows that adiponectin and visfatin are oppositely associated with BMD. Although the mechanisms behind these correlations are unclear, a modulation of bone metabolism by these adipokines can be suggested.

Role of adipocytokines in predicting the development of diabetes and its late complications

Diabetes is an important health problem since the incidence of diabetes is continuously increasing. Early diagnosis is important as type 2 diabetes begins long before we diagnose it, leading to a complicated course of the disease. In order to prevent delay in the diagnosis of type 2 diabetes, novel predictors and pathways for type 2 diabetes are mounting. Diabetic complications are common cause of morbidity and mortality among subjects with diabetes. In the pathogenesis of diabetic complications some factors other than chronic hyperglycemia may be involved. Adipocytokines play important roles in the pathogenesis of diabetes mellitus, insulin resistance, and associated metabolic conditions such as hypertension and dyslipidemia. The investigations on the role of adipocytokines in developing diabetes and its complications have been made. In this review, we discussed the implications of adipocytokines in predicting diabetes and diabetic complications, with particular attention on the roles of adiponectin, leptin, visfatin, and vaspin.

Potential markers of preeclampsia--a review

Preeclampsia is a leading cause of maternal and fetal/neonatal mortality and morbidity worldwide. The early identification of patients with an increased risk for preeclampsia is therefore one of the most important goals in obstetrics. The availability of highly sensitive and specific physiologic and biochemical markers would allow not only the detection of patients at risk but also permit a close surveillance, an exact diagnosis, timely intervention (e.g. lung maturation), as well as simplified recruitment for future studies looking at therapeutic medications and additional prospective markers. Today, several markers may offer the potential to be used, most likely in a combinatory analysis, as predictors or diagnostic tools. We present here the current knowledge on the biology of preeclampsia and review several biochemical markers which may be used to monitor preeclampsia in a future, that, we hope, is not to distant from today.

Is visfatin an adipokine or myokine? Evidence for greater visfatin expression in skeletal muscle than visceral fat in chickens

Visfatin, an adipokine hormone produced primarily by visceral adipose tissue in mammals, has been implicated in the immune system, cellular aging, and glucose metabolism. Increased visceral adiposity and hyperglycemia have been correlated with elevated plasma visfatin levels in humans. The present study investigated visfatin cDNA and protein expression as well as plasma visfatin levels in chickens that are selected for rapid growth and are naturally hyperglycemic relative to mammals. By RT-PCR, we detected visfatin cDNA in multiple tissues in the chicken. The deduced amino acid sequence of full-length chicken visfatin was 92-93% homologous to mammalian visfatin. Using real-time quantitative PCR and Western blotting, chicken skeletal muscle was found to contain 5- and 3-fold greater quantities of visfatin mRNA and protein than abdominal fat pad, respectively. Visfatin mRNA and protein quantities were not significantly different among sc and visceral adipose tissue depots. Skeletal muscle visfatin mRNA and protein quantities as well as plasma visfatin levels determined by enzyme immunoassay were significantly higher in 8-wk-old compared with 4-wk-old chickens, possibly due to rapid skeletal muscle growth and visceral fat accretion occurring in broiler chickens during this period. However, fasting and refeeding did not affect plasma visfatin levels in the chicken. Collectively, our results provide novel evidence that skeletal muscle, not the visceral adipose tissue, is the primary source of visfatin in chickens, thereby raising the possibility that visfatin may be acting as a myokine affecting skeletal muscle growth and metabolism.

Pre-B cell colony-enhancing factor/visfatin, a new marker of inflammation in rheumatoid arthritis with proinflammatory and matrix-degrading activities

OBJECTIVE

To study possible mechanisms that mediate induction of the recently described adipocytokine pre-B cell colony-enhancing factor (PBEF) in joints of patients with rheumatoid arthritis (RA), and to analyze whether levels of PBEF correlate with disease severity and whether PBEF itself has the potential to act as a proinflammatory and destructive mediator in RA.

METHODS

RA synovial fibroblasts (RASFs) and monocytes were stimulated with Toll-like receptor (TLR) ligands, cytokines, and recombinant human PBEF or were transfected with PBEF expression constructs or with PBEF-specific small interfering RNA. Production of interleukin-6 (IL-6), IL-8, and tumor necrosis factor alpha (TNFalpha) was measured by enzyme-linked immunosorbent assay, and expression of matrix metalloproteinases (MMPs) was assessed by real-time polymerase chain reaction. PBEF expression in synovial tissue, synovial fluid, serum, and SFs was assessed by immunohistochemistry, in situ hybridization, Western blotting, and enzyme immunoassays.

RESULTS

In RASFs, PBEF was up-regulated by TLR ligands and cytokines that are characteristically present in the joints of patients with RA. In synovial tissue, RASFs were the major PBEF-expressing cells. A predominance of PBEF was found in the synovial lining layer and at sites of invasion into cartilage. Levels of PBEF in serum and synovial fluid correlated with the degree of inflammation and clinical disease activity. Moreover, PBEF itself activated the transcription factors NF-kB and activator protein 1 and induced IL-6, IL-8, MMP-1, and MMP-3 in RASFs as well as IL-6 and TNFalpha in monocytes. PBEF knockdown in RASFs significantly inhibited basal and TLR ligand-induced production of IL-6, IL-8, MMP-1, and MMP-3.

CONCLUSION

Our findings establish PBEF as a proinflammatory and destructive mediator of joint inflammation in RA and identify PBEF as a potential therapeutic target.