Adiponectin: Serum-saliva associations and relations with oral and systemic markers of inflammation

Correlation of serum biochemical parameters and saliva pH in healthy individuals

Saliva has the potential to work alongside needles in standard medical diagnosis. Yet the number of studies aimed at deciphering the biochemical communication between saliva and the rest of the body's systems is still very limited. The aim of this study is to investigate the interfluid interaction between saliva and serum by determining the correlation between saliva pH and serum biochemical parameters under mild conditions. Ultimately, using saliva may provide a stress-free diagnostic tool, but more ambitiously, the pH of saliva could present a genuine cost-effective screening tool that may immensely benefit areas with limited access to health care and diagnostic labs. Saliva and blood samples were collected from 43 randomly selected children (7-12 years), living in Jeddah, free from obesity and chronic or systemic body and mouth diseases. A complete serum biochemical analysis was performed, and the salivary pH of all samples was measured immediately at the time of collection. The correlations between saliva pH and serum biochemical parameters were investigated using Univariate and multiple linear regression models. Our results showed that pH has a weak significant positive correlation with total protein and a negative weak significant correlation with urea. Weak correlations suggest the existence of more serum factors to be investigated for their effect on the pH using a stepwise multiple linear regression. The multiple linear models' calculated saliva pH values were close to the measured values, demonstrating its possible capacity to predict saliva pH using serum parameters. The regression model's successful prediction of saliva pH using serum biochemicals reflects the significant correlations between the body fluids' parameters and invites more research to elucidate these relationships.

Oral microbial communities in children, caregivers, and associations with salivary biomeasures and environmental tobacco smoke exposure

Human oral microbial communities are diverse, with implications for oral and systemic health. Oral microbial communities change over time; thus, it is important to understand how healthy versus dysbiotic oral microbiomes differ, especially within and between families. There is also a need to understand how the oral microbiome composition is changed within an individual including by factors such as environmental tobacco smoke (ETS) exposure, metabolic regulation, inflammation, and antioxidant potential. Using archived saliva samples collected from caregivers and children during a 90-month follow-up assessment in a longitudinal study of child development in the context of rural poverty, we used 16S rRNA gene sequencing to determine the salivary microbiome. A total of 724 saliva samples were available, 448 of which were from caregiver/child dyads, an additional 70 from children and 206 from adults. We compared children's and caregivers' oral microbiomes, performed "stomatotype" analyses, and examined microbial relations with concentrations of salivary markers associated with ETS exposure, metabolic regulation, inflammation, and antioxidant potential (i.e., salivary cotinine, adiponectin, C-reactive protein, and uric acid) assayed from the same biospecimens. Our results indicate that children and caregivers share much of their oral microbiome diversity, but there are distinct differences. Microbiomes from intrafamily individuals are more similar than microbiomes from nonfamily individuals, with child/caregiver dyad explaining 52% of overall microbial variation. Notably, children harbor fewer potential pathogens than caregivers, and participants' microbiomes clustered into two groups, with major differences being driven by Streptococcus spp. Differences in salivary microbiome composition associated with ETS exposure, and taxa associated with salivary analytes representing potential associations between antioxidant potential, metabolic regulation, and the oral microbiome. IMPORTANCE The human oral cavity is a multi-environment habitat that harbors a diversity of microorganisms. This oral microbiome is often transmitted between cohabitating individuals, which may associate oral and systemic health within family members. Furthermore, family social ecology plays a significant role in childhood development, which may be associated with lifelong health outcomes. In this study, we collected saliva from children and their caregivers and used 16S rRNA gene sequencing to characterize their oral microbiomes. We also analyzed salivary biomeasures of environmental tobacco smoke exposure, metabolic regulation, inflammation, and antioxidant potential. We show there are differences in individuals' oral microbiomes mainly due to Streptococcus spp. that family members share much of their microbes, and several bacterial taxa associate with the selected salivary biomeasures. Our results suggest there are large-scale oral microbiome patterns, and there are likely relationships between oral microbiomes and the social ecology of families.

Associations between saliva and plasma cytokines in cognitively normal, older adults

BACKGROUND

Inflammatory responses play key roles in the development and progression of many pathological conditions, including neurodegenerative diseases. Accurate quantification of inflammatory factors in saliva would be highly advantageous, given its convenience and non-invasive nature, especially in elderly populations.

METHODS

In this study, we measured levels of 10 cytokines, and the pro-inflammatory factor, YKL-40, in plasma and saliva samples from a cohort of nondemented older adults (n = 71; 62% female; 70.3 ± 6.4 years) using sensitive electrochemiluminescence-based immunoassays.

RESULTS

We found that the mean levels of all cytokines were higher in saliva compared to plasma and that strong sex differences were observed for both saliva and plasma cytokines in this population. Comparing each cytokine between the two biofluids, we found that levels of interferon-gamma (IFNγ), interleukin (IL)-6 and tumor necrosis factor-alpha (TNFα) in blood were significantly correlated with their respective levels in saliva. We further observed that levels of these cytokines in blood were significantly correlated with additional cytokines in saliva, including IL-1β, IL-10, IL-8, IL12p70 and IL-13.

CONCLUSIONS

These findings show that inflammatory markers in saliva are associated with those found in circulation, suggesting shared inflammatory mechanisms between these two fluids. The higher levels of cytokines measured in saliva suggest that it might represent a better peripheral fluid to gauge inflammatory processes. Finally, our findings of robust sex differences in several salivary cytokines could have important implications for their potential use as disease biomarkers in the elderly and might be related to sex differences in the prevalence of age-related conditions.

Validation and verification of predictive salivary biomarkers for oral health

Oral health is important not only due to the diseases emerging in the oral cavity but also due to the direct relation to systemic health. Thus, early and accurate characterization of the oral health status is of utmost importance. There are several salivary biomarkers as candidates for gingivitis and periodontitis, which are major oral health threats, affecting the gums. These need to be verified and validated for their potential use as differentiators of health, gingivitis and periodontitis status, before they are translated to chair-side for diagnostics and personalized monitoring. We aimed to measure 10 candidates using high sensitivity ELISAs in a well-controlled cohort of 127 individuals from three groups: periodontitis (60), gingivitis (31) and healthy (36). The statistical approaches included univariate statistical tests, receiver operating characteristic curves (ROC) with the corresponding Area Under the Curve (AUC) and Classification and Regression Tree (CART) analysis. The main outcomes were that the combination of multiple biomarker assays, rather than the use of single ones, can offer a predictive accuracy of > 90% for gingivitis versus health groups; and 100% for periodontitis versus health and periodontitis versus gingivitis groups. Furthermore, ratios of biomarkers MMP-8, MMP-9 and TIMP-1 were also proven to be powerful differentiating values compared to the single biomarkers.

Best practice recommendations for the measurement and interpretation of salivary proinflammatory cytokines in biobehavioral research

Despite the integration of salivary inflammatory cytokines into research across the biobehavioral, psychological, clinical, and health-related disciplines, there is little guidance regarding the biospecimen collection, handling, and storage practices that maximize the quality and validity of salivary cytokine data. Furthermore, associations between salivary cytokines and measures related to oral health are rarely assessed and accounted for in studies outside the oral health fields. To address these gaps, we examine the sensitivity of salivary interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor-α (TNF-α) to changes in saliva sample collection technique and cold chain management procedures. Using subsets of saliva samples collected from 150 healthy adults, we measure salivary IL-1β, IL-6, IL-8, TNF-α, and other oral health-related indices (i.e., blood contamination [transferrin], and salivary matrixmallotprotienase-8). In addition to examining changes in cytokine levels associated with sample collection technique and cold chain management procedures, we assess relations between cytokine concentrations and levels of other oral health-related measures. We found that IL-1β, IL-6, and IL-8 were more robust to changes in sample collection and cold chain management procedures than TNF-α, and all cytokines were positively associated with other oral health-related measures. Based on our findings, we recommend analyte-specific guidance for measuring and interpreting salivary cytokine concentrations.

Adjustments for oral fluid quality and collection methods improve prediction of circulating tetanus antitoxin: Approaches for correcting antibody concentrations detected in a non-invasive specimen

OBJECTIVES

To examine whether anti-tetanus toxoid (anti-TT) immunoglobulin G (IgG) levels measured in oral fluid and adjusted for collection difficulties and specimen quality are associated with total IgG and anti-TTIgG in oral fluid and assess if statistical adjustment for them improves prediction of anti-TT IgG in serum.

METHODS

267 children, ages 12 to 15 months, enrolled in the M-SIMU randomized controlled trial participated in this nested cross-sectional analysis. Venous blood and oral fluid (OF) specimens were collected, and OF collection difficulties such as crying or gagging were recorded. OF volume was documented and total IgG was measured in OF specimens and anti-TT IgG was measured in OF and serum by enzyme immunoassay (EIA). Collection difficulties, volume and sociodemographic characteristics were assessed in relation to total IgG and anti-TT IgG in OF via multivariate regression. These models were extended to evaluate the association between anti-TT IgG in OF and in serum. A prediction model was developed to adjust anti-TT IgG in OF estimates as proxy for serum.

RESULTS

Blood in the specimen, sores in the mouth and crying were positively associated with total IgG concentration while high oral fluid volume and sucking on the swab were inversely associated. None were significant predictors of anti-TT IgG in OF after adjusting for total IgG (geometric mean [GM] ratio: 1.99; 95% confidence interval: 1.78-2.24) and vaccination history (GM ratio: 2.44; 95% CI: 1.98-3.01). When predicting anti-TT IgG levels in serum with OF, total IgG modified the effect of anti-TT IgG in OF.

CONCLUSIONS

Anti-TT IgG in OF is a good proxy for levels in serum, after controlling for total IgG in the specimen and other variables. Post hoc adjustments for OF volume and total IgG concentration are an important consideration when conducting serosurveys with oral fluid.

Correspondence Between Cytomegalovirus Immunoglobulin-G Levels Measured in Saliva and Serum

Human cytomegalovirus (HCMV) infects more than 80% of the global population. While mostly asymptomatic, HCMV infection can be serious among the immunocompromised, and it is implicated in chronic disease pathophysiology in adulthood. Large-scale minimally invasive HCMV screening could advance research and public health efforts to monitor infection prevalence and prevent or mitigate downstream risks associated with infection. We examine the utility of measuring HCMV immunoglobulin-G (IgG) levels in saliva as an index of serum levels. Matched serum and saliva samples from healthy adults (N = 98; 44% female; 51% white) were assayed for HCMV IgG, total salivary protein, and salivary markers related to oral inflammation, blood, and tissue integrity. We examine the serum-saliva association for HCMV IgG and assess the influence of participant characteristics and factors specific to the oral compartment (e.g., oral inflammation) on HCMV IgG levels and cross-specimen relations. We found a robust serum-saliva association for HCMV IgG with serum antibody levels accounting for >60% of the variance in salivary levels. This relation remained after adjusting for key demographic and oral immune-related variables. Compared to the serum test, the salivary HCMV IgG test had 51% sensitivity and 97% specificity. With improvements in assay performance and sample optimization, HCMV antibody levels in oral fluids may be a useful proxy for serum levels.

Complement split product C3c in saliva as biomarker for periodontitis and response to periodontal treatment

Background and Objective

The complement system is engaged in inflammatory reactions both in the periodontal pockets and in the periodontium itself, where it can mediate tissue destruction. The aim of this study was, first, to compare salivary levels of the total complement system protein C3 and its split product, fluid‐phase C3c in patients with periodontitis and periodontally healthy controls. Next, to determine if C3 and C3c levels had biomarker potential in diagnosing and monitoring periodontitis and its treatment. We hypothesized that salivary levels of total C3 and the split product C3c associated with the severity of periodontitis and reflected decreased inflammatory activity after periodontal treatment.

Methods

At baseline, stimulated saliva samples were collected from patients with periodontitis (n = 18) and periodontally healthy controls (n = 15). Subsequently, non‐surgical periodontal treatment was performed in the patients, and saliva sampling from patients was repeated two‐, six‐, and twelve weeks post‐treatment (NCT02913248 at clinicaltrials.gov).

The patients were grouped as good and poor responders to treatment according to the achieved reduction in bleeding on probing (BOP).

Salivary levels of C3 and C3c were quantified using sandwich ELISA.

Results

Patients with periodontitis had higher baseline levels of both total C3 and the split product C3c in saliva than did periodontally healthy controls (P < .0001). Receiver operating curve (ROC) analyses discriminated patients with periodontitis from controls based on both C3 (AUC (area under curve) = 0.91, P < .001) and C3c levels (AUC = 0.84, P < .001) in saliva. Periodontal treatment improved all clinical parameters (P < .01). Good responders (n = 10) had lower baseline levels of C3c than poor responders (n = 8), (P < .05), and baseline levels of C3c discriminated between good and poor responders (AUC = 0.80, P < .05).

Conclusion

In conclusion, patients with periodontitis had higher salivary levels of C3c, and the C3c levels were predictive of reductions in BOP, that is, the poor responders. This suggests that salivary C3c levels possess potential to serve as a biomarker predicting the clinical response to non‐surgical periodontal treatment.

Bone turnover markers in serum but not in saliva correlate with bone mineral density

Saliva was proposed as a diagnostic tool for systemic diseases. Here we determined the correlation of bone turnover markers in saliva, bone turnover markers in serum and bone mineral density in postmenopausal osteoporotic and healthy women. Forty postmenopausal osteoporotic and 40 age-matched healthy non-osteoporotic females were recruited for this case–control study. Serum and stimulated saliva levels of osteocalcin, N-terminal propeptide of type I collagen, bone-specific alkaline phosphatase and cross-linked-C-telopeptide of type I collagen were determined. Bone mineral density of the lumbar spine, proximal femur, and total hip were obtained. We show that osteocalcin and cross-linked-C-telopeptide of type I collagen (CTX) reached detectable levels in saliva while N-terminal propeptide of type I collagen and alkaline phosphatase were close or below the detection limit. Serum levels of bone turnover markers were significantly higher than saliva levels. Correlation analysis revealed a strong correlation of serum osteocalcin and, to a lesser extent, also serum CTX values with bone mineral density in lumbar spine, femoral neck, or total hip, respectively. There was, however, no significant correlation of bone mineral density with the respective bone turnover markers in saliva. There was a trend that saliva osteocalcin correlates with femoral neck (p = 0.16) or total hip (p = 0.06). There was also no association between serum and saliva bone turnover markers. This study reveals that saliva cannot replace the withdrawal of serum to evaluate bone metabolism.

Age and gender characteristics of the biochemical composition of saliva: Correlations with the composition of blood plasma

Background

Recently, the attention of researchers to the study of the properties of human saliva, as a material with unique properties and diagnostic capabilities, has increased.

Research objective

to study the connection of the biochemical composition of saliva and blood plasma in the norm, depending on gender and age.

Methods

107 volunteers took part in the study, including 46 female (37.2 ± 3.9 years old) and 61 male (36.1 ± 2.8 years old). In all samples of saliva and blood plasma, 16 biochemical parameters were determined, including mineral and protein composition, enzyme activity. Non-parametric statistical methods were used to process the data.

Results

It has been shown that it is difficult to establish an unambiguous relation between biochemical parameters of saliva and blood plasma. The calculation of the Spearman correlation coefficients showed that only 7 of the 16 parameters demonstrate the presence of a weak correlation between the content in saliva and plasma.

Conclusion

In general, the determination of the composition of saliva may have an independent diagnostic value; in this case, drawing a parallel with the composition of serum and blood plasma is not advisable. Nevertheless, the use of saliva in clinical laboratory diagnostics is associated with the need to establish criteria for the norm and pathology for each biochemical parameter.

Salivary total Immunoglobulin G as a surrogate marker of oral immune activity in salivary bioscience research

The integration of salivary biomeasures in biobehavioral, psychophysiological, and clinical research has greatly expanded our ability to study the biopsychosocial processes underlying health. Much of this research, however, has failed to adequately assess and adjust for the impact of oral immune activity on salivary biomeasure concentrations and associations with serum levels. Aiming to improve the validity and reliability of salivary biomeasure data, we examine salivary total Immunoglobulin G (IgG) as a potential surrogate marker of oral inflammation and immune activity. During a single study visit in Baltimore, Maryland, healthy young adult participants provided matched blood and saliva samples (N=99; age 18-37 years, 42% female) and completed an oral health questionnaire. Biospecimens were assayed for total IgG and immune markers related to inflammation (cytokines), blood in saliva (transferrin), and tissue remodeling (matrix metalloproteinase-8). Total IgG (μg/mL) concentrations were higher in serum than saliva. Salivary total IgG was associated with some self-reported oral health measures, and strongly positively associated with all salivary immune markers. Controlling for salivary total IgG may be a feasible, affordable approach to adjusting salivary biomeasure findings for the influence of the oral immune environment when it is not possible or practical to obtain clinical oral health data.

Association between obesity and adipokines levels in saliva and gingival crevicular fluid: A systematic review and meta-analysis

AIM

This systematic review and meta-analysis aimed to compare adipokines' levels in gingival crevicular fluid (GCF) and saliva between individuals with obesity and individuals without obesity.

METHODS

Computerized searches were conducted in four electronic databases (PubMed, Medline via Ovid, Web of Science, and Scopus). Manual searches and a Google Scholar search, limiting the search to the first 100 hits, were also conducted. Two calibrated authors performed the study selection, data extraction, and quality assessment of included articles. The quality of the included articles was evaluated using the University of Adelaide Tool.

RESULTS

The electronic searches retrieved 929 titles/abstracts. Following the removal of duplicated references, 613 titles/abstracts were assessed. Thirty-four articles were included. Meta-analysis demonstrated that tumor necrosis factor-α (TNF-α) concentration in saliva was statistically increased in individuals with obesity compared with individuals without obesity (P < 0.05). By contrast, the meta-analysis showed no difference in the concentrations of resistin, adiponectin, leptin, ghrelin, and interleukin 6 in saliva and of resistin, adiponectin, leptin, interleukin 6, interleukin 8, tumor necrosis factor α, and plasminogen activator inhibitor 1 in GCF between individuals with and without obesity (P > 0.05).

CONCLUSIONS

Individuals with obesity presented higher levels of TNF-α in saliva than individuals without obesity. TNF-α in saliva sampling may be a helpful marker for obesity. For the other adipokines, no difference was observed, but the limited availability and heterogeneity of data do not allow us to assertively state whether changes of adipokines in GCF and saliva are associated with obesity.

Serum and salivary adiponectin dynamics in septic and non-septic systemic inflammation in a canine model

Adiponectin is a 30 kDa protein hormone that has anti-atherogenic properties, being an insulin-sensitizing and anti-inflammatory molecule. Salivary adiponectin concentrations correlate positively with serum, thus, saliva was indicated as appropriate biofluid for its measurement in different clinical situations. However, inflammation was indicated as main confounding factor when evaluating the usefulness and the reliability of determination of salivary adiponectin. The aim of the present report was to evaluate the dynamics of salivary and serum adiponectin in systemic non-septic and septic inflammation using a dogs as a model. Forty bitches were enrolled. Seventeen dogs were healthy (group I, non-septic) and 23 bitches were diagnosed with pyometra (group II, septic). Ovariohysterectomy was performed for all animals. Saliva and blood samples were collected before (D0) and 3 (D3) and 10 (D10) days after ovariohysterectomy. At D0, Group I showed higher serum and salivary adiponectin than group II, although statistical significance was only detected in salivary adiponectin between the two groups at D0 (P = 0.001). In serum, adiponectin was higher on D0 than on D3 and tended to reach pre-surgery values on D10 in both groups. Salivary adiponectin showed similar behaviour to serum in Group I, while in group II salivary adiponectin concentrations were lowest on D0 and tended to increase on D3 and D10. The data obtained in present study describe for the first time the comparative behavior of salivary adiponectin in non-septic and septic inflammation. Salivary, and not serum, adiponectin seemed to mimic better the inflammatory and general health status.

Salivary Inflammatory Markers in Trichotillomania: A Pilot Study

BACKGROUND

Immune dysregulation has been hypothesized to be important in the development and pathophysiology of compulsive disorders such as obsessive compulsive disorder (OCD), which has a high comorbid overlap with trichotillomania (both are OC-related disorders). The role of inflammation in the pathophysiology of trichotillomania has garnered little research to date.

METHODS

Individuals with trichotillomania provided saliva sample for analysis of inflammatory cytokines. Additionally, these participants were examined on a variety of demographic variables (including body mass index [BMI], previously found to relate to inflammation) along with clinical measures (symptom severity, functioning, and comorbidity).

RESULTS

Thirty-one participants, mean age of 24.7 (±10.2) years, 27 (87.1%) females were -included. The mean score on the Massachusetts General Hospital Hair Pulling Scale was 15.7 (±4.2), reflective of moderate symptom severity. Compared to normative data, the mean inflammatory marker levels in the trichotillomania sample had the following Z scores: interleukin-1β (IL-1β) Z = -0.26, IL-6 Z = -0.39, IL-8 Z = -0.32, and tumor necrosis factor-α Z = -0.83. Levels of inflammatory markers did not correlate significantly with BMI, depressive mood, symptom severity, or disability.

CONCLUSIONS

The relatively low level of inflammatory saliva cytokines observed in the current study (negative z scores versus normative data with medium effect sizes) indicates that evaluation of blood inflammatory levels in trichotillomania versus matched controls would be valuable in future work. If a hypoinflammatory state is confirmed -using blood samples, this would differentiate trichotillomania from other mental disorders (such as OCD, schizophrenia, and depression), which have typically been linked with high inflammatory measures in the literature, at least in some cases.

Household fear of deportation in relation to chronic stressors and salivary proinflammatory cytokines in Mexican-origin families post-SB 1070

Sociologists recognize that immigration enforcement policies are forms of institutionalized racism that can produce adverse health effects in both undocumented and documented Latinos and Mexican-origin persons in the United States. Despite this important advancement, little research examines the relationship between fear of immigration enforcement and biobehavioral health in mixed-status Mexican-origin families. This study applies an embodiment of racism approach to examine how household fear of deportation (FOD) is related to differences in salivary proinflammatory cytokines (IL-1 β , IL-6, IL-8, and TNF α ) in healthy Mexican-origin families with at least one immigrant, living in Phoenix, AZ. Participants were 111 individuals (n=46 adults, 72% female; n=65 children, 49% female) from 30 low-income, mixed-status families. During a home visit, anthropometric measures and saliva were collected from each family member and a household survey was administered. Saliva was assayed for salivary IL-1 β , IL-6, IL-8, and TNF α . Random effects multilevel structural equation models estimated the relationship between household FOD and a salivary proinflammatory cytokine latent variable between families, while controlling for other chronic stressors (economic/occupational, immigration, parental, and family conflict). Household FOD ( β =0.68, p=0.04) and family conflict chronic stress ( β =1.96, p=0.03) were strongly related to elevated levels of proinflammatory cytokines between families. These results were consistent in non-mixed and mixed-status families. Future research is needed to characterize what aspects of living with an undocumented family member shape the physical health outcomes of persons with authorized status or US-citizenship.

The validity, stability, and utility of measuring uric acid in saliva

AIM

Serum uric acid (UA) is associated with many health conditions, including kidney, cardiovascular, and metabolic disorders. We examined the validity and stability of salivary UA as a noninvasive measure of serum UA.

MATERIALS & METHODS

Using serum and salivary UA data from healthy adults (n = 99), we examined the UA serum-saliva correlation, and UA associations with adiponectin and C-reactive protein. Using longitudinal data from young adults (n = 182), we examined salivary UA stability.

RESULTS

We found robust positive serum-saliva correlations for UA. UA and adiponectin were inversely related in serum and saliva. Salivary UA was relatively stable; 62-66% of variance could be attributed to a latent trait-like component.

CONCLUSION

Salivary UA may be an important biomarker indexing health and disease risk.

Serum levels of selected adipocytokines in benign and malignant parotid gland tumor patients

OBJECTIVES

The aim of this study was to evaluate serum levels of adiponectin, leptin, visfatin and IL-6 in patients with pleomorphic adenoma, Warthin's tumor and acinic cell carcinoma of the parotid gland.

MATERIALS AND METHODS

Venous blood samples were collected from 30 patients with pleomorphic adenoma, 21 patients with Warthin's tumor and 8 patients with acinic cell carcinoma. Serum adiponectin, leptin, visfatin, IL-6 and CRP concentrations were determined.

RESULTS

Our results revealed significantly lower adiponectin serum levels in patients with malignant tumors compared to benign tumor individuals. Moreover, in benign cases the level was significantly higher compared to controls. Furthermore, serum leptin concentrations of benign tumor patients were higher compared to controls. Those differences, however, were observed only in males. The serum visfatin level was elevated in all tumor subjects compared to healthy individuals, whereas the serum IL-6 concentration was similar.

CONCLUSIONS

We anticipate that adiponectin may play a potential protective role in salivary gland tumors. Also leptin and visfatin seem to play an important role in salivary gland tumor pathology, although in males and females leptin may act or be regulated in a different manner. The influence of visfatin on salivary gland tumors is probably independent of IL-6 production.