Metabolic disease risk in children by salivary biomarker analysis

Serum and salivary adiponectin levels as predictive markers for diabetes mellitus in children with a family history of diabetes

Diabetes mellitus (DM) is a chronic, metabolic condition marked by defects in insulin production, action, or both. Environmental and genetic factors can contribute to the onset of diabetes mellitus. Adiponectin, a hormone affecting pancreatic beta cell proliferation, has emerged as a potential indicator of diabetes risk. This cross-sectional study aimed to evaluate serum and salivary adiponectin levels as predictors of diabetes mellitus in children with/without a family history of diabetes mellitus. The study was conducted at Al-Zahra Hospital in Najaf city and included 125 children aged 5 to 16. Data on demographics, including name, age, and gender, were collected, and body mass index (BMI) was assessed. Serum and salivary adiponectin levels were measured and analyzed in relation to family history and BMI. Children with a family history of DM had high serum adiponectin (ADP) levels. Serum adiponectin levels were significantly higher in children with first-degree relatives having a history of diabetes mellitus, except for cases involving mothers and other relatives with diabetes mellitus history (p<0.05). Furthermore, serum adiponectin levels were higher in obese children. Salivary adiponectin levels were significantly elevated in children with a maternal family history of diabetes (p=0.01), while no significant correlation was found with BMI. A significant negative correlation (r=-0.180, p=0.05) between salivary and serum adiponectin concentrations was observed. Compared to children with a normal, healthy weight, children with obesity had decreased salivary adiponectin levels and increased serum adiponectin levels.

Saliva insulin tracks plasma insulin across the day following high-carbohydrate and low-carbohydrate meals

Non-invasive monitoring of insulin could hold promise to identify those with, or at risk for developing, insulin resistance. We aimed to examine saliva insulin responses across the day following high- and low-carbohydrate meals and evaluate whether changes in saliva insulin might accurately reflect changes in plasma insulin. In two randomized crossover studies, young normal weight men (NW; n = 8; Study 1) and adults with overweight/obesity (OO; n = 8; Study 2) completed two 9-h experimental trials in which the participants consumed isocaloric mixed high-carbohydrate (HC) or low-carbohydrate (LC) meals at 0, 3, and 6 h. Plasma and saliva samples were collected at fasted baseline and every 30 min for a total of 19 samples across 9 h. Overall, findings revealed a similar trend for postprandial saliva and plasma insulin responses regardless of the time of the day with a ∼30-45 min lag between saliva and plasma insulin responses. In both NW and OO groups, saliva and plasma insulin area under the curve (AUC) and incremental AUC were significantly higher in HC condition as compared to LC condition (all P ≤ 0.002). Nine-hour plasma and saliva insulin total AUCs were strongly and very strongly correlated in both HC (r = 0.68; P = 0.007) and LC (r = 0.84, P < 0.001) conditions, respectively. Saliva insulin is proportionate to and appears to reasonably track plasma insulin across the day with a ∼30-45 min delay. Saliva insulin shows promise as a non-invasive method to discern between low and high plasma insulin and may have utility in predicting the degree of insulin resistance (NCT03374436).

The relationship between sleep and salivary and serum inflammatory biomarkers in adolescents

Objectives

Poor sleep behavior can trigger an inflammatory response and contribute to the development of inflammatory diseases. Cytokines can act as indicators of inflammation and may precede the onset of inflammatory diseases. This study aimed to determine the association between sleep timing parameters (bedtime, sleep duration, sleep debt, and social jetlag) and the levels of nine serum and salivary inflammatory and metabolic biomarkers.

Methods

Data were collected from 352 adolescents aged 16-19 years enrolled in Kuwait's public high schools. The levels of C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), adiponectin, leptin, and insulin were measured from saliva and serum samples. We conducted mixed-effect multiple linear regression modeling to account for the school variable as a random effect to assess the relationship between the sleep variables and salivary and serum biomarkers. Mediation analysis was conducted to check if BMI was a mediator between bedtime and the biomarkers.

Results

There was a statistically significant elevation in serum IL-6 level associated with later bedtime (0.05 pg./mL, p = 0.01). Adolescents with severe sleep debt of ≥2 h had an increase in salivary IL-6 biomarker levels (0.38 pg./mL, p = 0.01) compared to those who had sleep debt of <1 h. Adolescents with sleep debt of ≥2 h had significantly higher levels of serum CRP (0.61 μg/mL, p = 0.02) than those without sleep debt. Additionally, we found that the inflammatory biomarkers (CRP, IL-6, IL-8, IL-10, VEGF, and MCP-1) and metabolic biomarkers (adiponectin, leptin, and insulin) had more statistically significant associations with the bedtime variables than with sleep duration variables. CRP, IL-6, and IL-8 were associated with sleep debt, and IL-6, VEGF, adiponectin, and leptin levels were associated with social jetlag. BMIz was a full mediator in the relationship between late bedtime and increased serum levels of CRP, IL-6, and insulin.

Conclusion

Adolescents who go to bed at or later than midnight had dysregulated levels of salivary and serum inflammatory biomarkers, suggesting that disrupted circadian rhythm can trigger higher levels of systemic inflammation and potentially exacerbate chronic inflammation and the risk of metabolic diseases.

The Role of the Preanalytical Step for Human Saliva Analysis via Vibrational Spectroscopy

Saliva is an easily sampled matrix containing a variety of biochemical information, which can be correlated with the individual health status. The fast, straightforward analysis of saliva by vibrational (ATR-FTIR and Raman) spectroscopy is a good premise for large-scale preclinical studies to aid translation into clinics. In this work, the effects of saliva collection (spitting/swab) and processing (two different deproteinization procedures) were explored by principal component analysis (PCA) of ATR-FTIR and Raman data and by investigating the effects on the main saliva metabolites by reversed-phase chromatography (RPC-HPLC-DAD). Our results show that, depending on the bioanalytical information needed, special care must be taken when saliva is collected with swabs because the polymeric material significantly interacts with some saliva components. Moreover, the analysis of saliva before and after deproteinization by FTIR and Raman spectroscopy allows to obtain complementary biological information.

The Role of Salivary C-Reactive Protein in Systemic and Oral Disorders: A Systematic Review

Background: Blood sampling is expensive, time-consuming, invasive, and requires technical facilities, which can be replaced by more convenient samples such as saliva. C-reactive protein (CRP) is a widely used biomarker in the management of many disorders and plasma CRP (pCRP) is suggested to be replaced by salivary CRP (sCRP). This study aimed to systematically review all available literature on the sCRP levels in systemic and oral disorders and how sCRP and pCRP levels correlate among these patients and healthy individuals. Methods: In this systematic review, a PubMed, Embase, Scopus, and Google Scholar search was conducted on October-2021 to identify all research investigating sCRP levels in systemic and oral disorders. Results: A total of 130 publications were analyzed in the review. Most of the studies reported that sCRP and pCRP levels are correlated, and sCRP is a reliable alternative for pCRP level for the diagnosis and management of medical conditions. sCRP has been measured in many different medical and oral disorders and significantly correlated with disease activity in most cases. Conclusion: Salivary CRP is a good alternative for Plasma CRP levels in most cases.

Comparison of Salivary Interleukin-6, Interleukin-8, C - reactive protein levels and Total Antioxidants Capacity of Obese Individuals with Normal Weight Ones

Objective: Obesity is a worldwide concern that may lead in type 2 diabetes, cardiovascular diseases, etc. Several serum biomarkers have been identified in the saliva of obese individuals, including inflammatory cytokines, adipokines, insulin, and cortisol. The present study aimed to compare salivary interleukin-6(IL-6), interleukin-8(IL-8), C-reactive protein (CRP) levels and total antioxidants capacity (TAC) of obese individuals with normal-weighted ones.

Methods: In this case–control study, 92 participants matched in terms of age and gender were placed into two groups according to the body mass index (BMI); case group: BMI>30 and control group: 18.5<BMI<24.99. Unstimulated saliva was collected. ELISA and FRAP method were used to determine IL-6, IL-8, CRP and TAC. Data was analyzed using SPSS 24, at the significant level of 0.05.

Results: Mean salivary levels of IL-6 and IL-8 in the normal individuals were 53.36 and 421.25ng/mL, with 86.09ng/mL and 510.19ng/mL in obese individuals, respectively. There were significant differences in the mean salivary levels of IL-6 and IL-8 between two experimental groups.

The mean salivary levels of CRP of control and case group was 2.84 and2.63 ng/mL and the total salivary antioxidant levels in the normal and obese individuals were 0.29 and 0.36, respectively which had no significant different.

Conclusion: According to the results of the present study, salivary levels IL-8 and IL-6 was significantly higher in obese individuals than in those with normal weight. However, the mean salivary CRP and TAC were not significantly different between the obese individuals and normal-weighted ones.

Pro-inflammatory and (Epi-)genetic markers in saliva for disease risk in childhood obesity

BACKGROUND AND AIM

Childhood obesity is an emerging problem often leading to earlier onset of non-communicable diseases in later life. Biomarkers to identify individual risk scores are insufficient in routine clinical practice, which is related to the need for easily sampled, non-invasive survey methods in children. We aimed to investigate and strengthen possible pro-inflammatory markers and epigenetic risk factors in saliva of obese children compared to lean controls.

METHODS AND RESULTS

19 overweight/obese (OC, 10.1 ± 1.9 years, BMI 27.7 ± 3.2 kg/m²) and 19 lean control children (CC, 9.7 ± 2.5 years, BMI 16.4 ± 1.8 kg/m²) participated in this explorative pilot study. Anthropometric measures, saliva and cheek swab samples were taken. Saliva profiles were examined for acute phase proteins (CRP and neopterin) and pro-inflammatory cytokines (IL-17a/IL-1β/IL-6). Cheek swabs were analyzed to investigate DNA methylation differences with subsequent hierarchical cluster and principal component analyses (PCA). Saliva analysis showed significant increased CRP concentrations in OC compared to CC (p < 0.001). There were no significant differences, but high intra-individual values in neopterin, IL-17a, IL-1β and IL-6. An unsupervised PCA of CpG loci with high variance (σ/σ_max > 0.2) clearly separated OC and CC according to their methylation pattern. Furthermore, a supervised approach revealed 7125 significantly differentially methylated loci, whose corresponding genes were significantly enriched for genes playing roles in e.g., cellular signalling, cytoskeleton organization and cell motility.

CONCLUSIONS

CRP and methylation status determinations in saliva are suitable as non-invasive methods for early detection of risks for non-communicable diseases in children/adolescents and might be a useful supplementary approach in the routine clinical practice/monitoring.

Comparison of C-Reactive Protein in Dried Blood Spots and Saliva of Healthy Adolescents

Background/Aim

Determining C-reactive protein (CRP) by non-invasive methods is of great interest for research addressing inflammation in young people. However, direct comparisons of such methods applied in children and adolescents are lacking so far. This study aimed to evaluate the association between CRP measured in dried blood spots (DBS CRP) and in saliva (sCRP), two less invasive alternatives to venipuncture, in 12- to 14-year-old adolescents. To evaluate the validity of both measurements in the context of biobehavioral studies, the potential of DBS CRP and sCRP to discriminate between defined BMI subgroups was assessed.

Materials and Methods

CRP levels in DBS and saliva collected from 87 healthy adolescents (M = 13.25 years, SD = 0.30, 51.7% females) were determined using high sensitive CRP ELISA for serum and salivary CRP ELISA, respectively. Characteristics and correlation of both measurements were assessed for the total sample and for three subgroups classified by BMI percentile ranges (A: ≤ 25; B: 26–74; C: ≥ 75).

Results

In the total sample, DBS CRP and sCRP were significantly associated (r = 0.59, p < 0.001). Splitting the sample into BMI-dependent subgroups revealed similarly strong associations of DBS CRP with sCRP for all three groups (A: r = 0.51; B: r = 0.61; C: r = 0.53). However, comparing the mean CRP values per BMI subgroup, one-way ANOVA reported significant differences for DBS CRP, but not for sCRP mean values.

Conclusions

The significant correlation of DBS CRP with sCRP was independent of the investigated BMI range groups, yet BMI-dependent distinction was only provided by DBS CRP mean values. Overall, our results suggest that DBS CRP is likely to reflect systemic inflammation more precisely. Salivary CRP can be alternatively determined in studies with adolescents when conditions require it, given the oral health status is assessed. Considering that DBS CRP and sCRP share only 35% of common variance, further studies should examine their specific validity.

Association between Frequency of Toothbrushing and Metabolic Syndrome among Adolescents: A 5-Year Follow-Up Study

This study longitudinally examines the relationship between the frequency of toothbrushing and the development of selected components of metabolic syndrome (MetS), along with the potential role of salivary biomarkers in this relationship. In 2014, 6317 12-year-old children underwent health examinations (T1), of which, 348 children participated in the second stage of data collection in 2019 (T2). The association between the change in the metabolic status during the 5-year follow-up examination (between T1 and T2) and frequency of toothbrushing was assessed using multinomial logistic regression analyses. At T2, healthy adolescents had significantly higher odds of toothbrushing twice or more daily compared with adolescents with components of MetS (OR = 1.99, 95% CI 1.15–3.45). Adolescents who were healthy at T1 but developed components of MetS at T2, had significantly higher frequencies of dining-out compared with adolescents with components of MetS at both T1 and T2 (OR = 0.09, 95% CI 0.02 to 0.49). Adolescents who were ‘healthy’ at both T1 and T2 had significantly (p < 0.05) lower levels of C-reactive protein (T2), insulin (T1 and T2), interleukin-6 (T1) and adiponectin (T1) compared with adolescents who had components of MetS. Toothbrushing and frequency of dining-out were associated with the presence of MetS components.

Determination of salivary concentrations of leptin and adiponectin, ability to reduce ferric ions and total antioxidant capacity of saliva in patients with severe early childhood caries

INTRODUCTION

One of the most common oral diseases affecting children is early childhood caries (ECC). The link between oxidative stress and ECC has been proven in numerous clinical studies. Technical and biological variability were so high in most of the studies that none of the markers have yet been proven suitable for routine clinical use. This study aimed to evaluate the antioxidant status and the levels of leptin and adiponectin in saliva of children with severe early childhood caries (S-ECC).

METHODS

Morning unstimulated saliva samples were collected from children (n = 40, 0-6 years old) for the evaluation of oxidative stress which were measured by total antioxidant capacity (TAC), and by the ferric reducing antioxidant power (FRAP) assays, as well as to assess the salivary levels of leptin and adiponectin. FRAP, TAC, leptin and adiponectin concentrations were evaluated in S-ECC group (n = 31) and caries free group CF (n = 9). All results were analyzed based on age and sex.

RESULTS

Overall median salivary leptin and adiponectin levels were 5.59 pg/mL and 24.86 ng/mL, respectively. Significantly lower leptin levels were observed in saliva of caries free children (4.66 pg/mL) than in the S-ECC group (6.64 pg/mL, p < 0.01). No significant difference was observed for adiponectin levels (S-ECC and CF, 25.31 and 23.2 ng/mL, respectively, p = 0.961). TAC and FRAP values of saliva had similar values in children with S-ECC and caries free children. TAC and FRAP values also remained stable with the age of the children, without significant differences with respect to sex.

CONCLUSION

The increased concentrations of leptin in saliva of children with S-ECC suggests that leptin may play a role in inflammatory and immune responses in the development of early childhood caries.

Salivary Adipokine and Cytokine Levels as Potential Markers for the Development of Obesity and Metabolic Disorders

Currently, the number of people suffering from obesity is increasing worldwide. In addition, the disease is affecting younger individuals. Therefore, it is essential to search for new diagnostic methods and markers for early assessment of the risk of obesity, metabolic disorders, and other comorbidities. The discovery of the secretory function of adipose tissue and coexistence of low-grade chronic inflammation with obesity set a new direction in this disease diagnosis using the assessment of the concentration of inflammatory markers secreted by adipose tissue. The aim of this review was to determine, based on previous findings, whether saliva can be useful in the diagnosis of obesity and its early metabolic complications and whether it can be an alternative diagnostic material to serum.

The ratio of morning cortisol to CRP prospectively predicts first-onset depression in at-risk adolescents

RATIONALE

Early-onset adolescent depression is related to poor prognosis and a range of psychiatric and medical comorbidities later in life, making the identification of a priori risk factors for depression highly important. Increasingly, dysregulated levels of immune and neuroendocrine markers, such as C-reactive protein (CRP) and cortisol, have been demonstrated as both precursors to and consequences of depression. However, longitudinal research with adolescent populations is limited and demonstrates mixed immuno-endocrine-depression links.

OBJECTIVE

This study explored the putative bidirectional relationship between salivary measures of cortisol (Cort) and CRP, including the novel Cort:CRP ratio and depression.

METHODS

Participants from the randomized control trial 'Sleep and Education: learning New Skills Early' (SENSE) Study were 122 adolescents at risk for depression (73 females) aged 12-16 years (M = 12.71 years, SD = 1.01 years) assessed at baseline (T1), post-intervention (T2), and a two-year follow-up (T3).

RESULTS

Logistic regression results demonstrated that adolescents with higher T1 Cort:CRP_morn ratio levels were two-fold more likely to develop a first-onset depressive disorder from T2 to T3 as compared to adolescents with lower Cort:CRP_morn ratio levels, β = 0.73, t (36) = 2.15, p = .04, OR = 2.08. This effect was not moderated by treatment condition (β = -1.38, t (13) = -1.33, p = .20) and did not change when controlling for known risk factors for depression, including sex, age, body-mass index, socio-economic status, T1 anxiety disorder, nor T1 sleep disturbance, anxiety, or depressive symptoms (β = 0.91, t (31) = 2.14, p = .04).

CONCLUSION

Results highlight potential immuno-endocrine dysregulation as an underlying risk factor for adolescent first-onset depression, and may inform the development of targeted, preventative biobehavioral treatment strategies for youth depression.

Obesity, oxidative DNA damage and vitamin D as predictors of genomic instability in children and adolescents

BACKGROUND/OBJECTIVES

Epidemiological evidence indicates obesity in childhood and adolescence to be an independent risk factor for cancer and premature mortality in adulthood. Pathological implications from excess adiposity may begin early in life. Obesity is concurrent with a state of chronic inflammation, a well-known aetiological factor for DNA damage. In addition, obesity has been associated with micro-nutritional deficiencies. Vitamin D has attracted attention for its anti-inflammatory properties and role in genomic integrity and stability. The aim of this study was to determine a novel approach for predicting genomic instability via the combined assessment of adiposity, DNA damage, systemic inflammation, and vitamin D status.

SUBJECTS/METHODS

We carried out a cross-sectional study with 132 participants, aged 10-18, recruited from schools and paediatric obesity clinics in London. Anthropometric assessments included BMI Z-score, waist and hip circumference, and body fat percentage via bioelectrical impedance. Inflammation and vitamin D levels in saliva were assessed by enzyme-linked immunosorbent assay. Oxidative DNA damage was determined via quantification of 8-hydroxy-2'-deoxyguanosine in urine. Exfoliated cells from the oral cavity were scored for genomic instability via the buccal cytome assay.

RESULTS

As expected, comparisons between participants with obesity and normal range BMI showed significant differences in anthropometric measures (p < 0.001). Significant differences were also observed in some measures of genomic instability (p < 0.001). When examining relationships between variables for all participants, markers of adiposity positively correlated with acquired oxidative DNA damage (p < 0.01) and genomic instability (p < 0.001), and negatively correlated with vitamin D (p < 0.01). Multiple regression analyses identified obesity (p < 0.001), vitamin D (p < 0.001), and oxidative DNA damage (p < 0.05) as the three significant predictors of genomic instability.

CONCLUSIONS

Obesity, oxidative DNA damage, and vitamin D deficiency are significant predictors of genomic instability. Non-invasive biomonitoring and predictive modelling of genomic instability in young patients with obesity may contribute to the prioritisation and severity of clinical intervention measures.

Host-Based Biomarkers in Saliva for the Diagnosis of Pulmonary Tuberculosis in Children: A Mini-Review

The diagnosis of pulmonary tuberculosis (TB) in children remains a significant challenge due to its paucibacillary nature, non-specificity of symptoms and suboptimal sensitivity of available diagnostic methods. In young children particularly, it is difficult to obtain high-quality sputum specimens for testing, with this group the least likely to be diagnosed, while most at risk of severe disease. The World Health Organization (WHO) has prioritized research into rapid biomarker-based tests for TB using easily obtainable non-sputum samples, such as saliva. However, the role of biomarkers in saliva for diagnosing TB in children has not been fully explored. In this mini-review, we discuss the value of saliva as a diagnostic specimen in children given its ready availability and non-invasive nature of collection, and review the literature on the use of host-based biomarkers in saliva for diagnosing active pulmonary TB in adults and children. Based on available data from adult studies, we highlight that combinations of cytokines and other proteins show promise in reaching WHO-endorsed target product profiles for new TB triage tests. Given the lack of pediatric research on host biomarkers in saliva and the differing immune response to TB infection between children and adults, we recommend that pediatric studies are now performed to discover and validate salivary host biosignatures for diagnosing pulmonary TB in children. Future directions for pediatric saliva studies are discussed, with suggestions for technologies that can be applied for salivary biomarker discovery and point-of-care test development.

Degree of Agreement Between Infant Serum and Salivary Concentration of Leptin and Adiponectin and Its Association With Infants' Feeding

BACKGROUND

Leptin and adiponectin, two adipokines involved in glucose and lipid metabolism, have been linked to regulation of growth in early infancy, energy balance, and metabolic disorders in childhood. The aim of this study was to determine if concentrations of leptin and adiponectin could be measured reliably in infants' saliva, to evaluate the degree of agreement with infant serum levels, and to explore their association with infant feeding status.

METHODS

A total of 34 infants were recruited after birth and followed for 20 weeks. After log-transformation of the values, a Bland-Altman graphical approach was used to summarize the direction of the difference between the serum and saliva values. Repeated measures mixed modeling was used to evaluate differences over time in these outcomes by feeding status.

RESULTS

Mean concentration of salivary leptin and adiponectin in infants was 3.7 (SD = .8) ng/mL and 2.9 (SD = 0.7) ng/mL, respectively. The degree of agreement between serum and saliva for log-transformed leptin and adiponectin values were relatively robust, albeit with a non-zero bias between the two methods, given that serum values were greater than corresponding saliva values for both adipokines in all infants. Each of the four repeated measures mixed models (one for each adipokine measure) had a significant main effect; however, the interaction between time and feeding status was not significant in any of the models.

CONCLUSION

This study demonstrated that leptin and adiponectin can be measured in infant saliva, but in some cases leptin concentrations may be more difficult to detect.

Salivary Stress/Immunological Markers in Crohn's Disease and Ulcerative Colitis

There is continuous and growing interest in research into new alternatives to standard biomarkers to detect and follow-up disease, reducing physical and psychological stress in patients needing regular and invasive medical examinations for the evaluation of pathologies, including inflammatory bowel diseases (IBD). Saliva is one of the most promising body fluids in the research of new biomarkers, thanks to the large number of molecules it contains. Many molecules present in saliva are often directly correlated to their concentration in the blood but may be affected by the condition of the oral cavity. This means that a careful selection of a specific biomarker is required for each pathology, especially pathologies such as IBD, which may induce inflammation in the oral cavity. Here, we analyze the currently used and the proposed new salivary biomarkers (i.e., calprotectin, cytokines, IgA, cortisol, and oxidative stress markers) for the detection and follow-up of the main subtypes of IBD, known as ulcerative colitis and Crohn's disease.

Late Eating Is Associated with Obesity, Inflammatory Markers and Circadian-Related Disturbances in School-Aged Children

Late eating has been shown to promote metabolic dysregulation and to be associated with obesity in adults. However, few studies have explored this association in children. We compared the presence of obesity, metabolic alterations and circadian-related disturbances between school-aged children who were early dinner eaters (EDE) or late dinner eaters (LDE). School-age children (n = 397; 8-12 years; mean BMI (range): 19.4 kg/m² (11.6-35.1); 30.5% overweight/obesity) from Spain were classified into EDE and LDE, according to dinner timing (Median: 21:07). Seven-day-dietary-records were used to assess food-timing and composition. Non-invasive tools were used to collect metabolic biomarkers (saliva), sleep and circadian-related variables (body-temperature and actigraphy). Compared to EDE, LDE were more likely to be overweight/obese [OR: 2.1 (CI: 1.33, 3.31); p = 0.002], and had higher waist-circumference and inflammatory markers, such as IL-6 (1.6-fold) (p = 0.036)) and CRP (1.4-fold) than EDE (p = 0.009). LDE had alterations in the daily patterns of: (a) body-temperature, with a phase delay of 26 min (p = 0.002), and a reduced amplitude (LDE = 0.028 (0.001) and EDE = 0.030 (0.001) (Mean (SEM); p = 0.039); (b) cortisol, with a reduced amplitude (LDE = 0.94 (0.02) and EDE = 1.00 (0.02); p = 0.035). This study represents a significant step towards the understanding of novel aspects in the timing of food intake in children.

Poor Oral Hygiene and High Levels of Inflammatory Cytokines in Saliva Predict the Risk of Overweight and Obesity

The study aimed to determine if oral hygiene influences not only oral health but also potentially metabolic disorders such as overweight or obesity. Participants were 94 patients: 40 with increased body mass and 54 with normal body mass. The methods included dental examination, a questionnaire concerning hygienic habits and an assessment of selected salivary inflammatory markers. The new parameter named “cleaning index” (describing the interaction between average time of tooth brushing in minutes and its frequency per day) significantly correlated with Body Mass Index (R_Spearman = 0.300). The multivariate regression model incorporating cleaning index, approximal plaque index, receptor 1 for tumor necrosis factor-alpha (TNFα-R1) and interleukin-15 (IL-15) had a high power to predict overweight or obesity (AUC = 0.894). Patients with poor oral hygiene (approximal plaque index >40%) were more than eight times more likely to suffer from obesity than patients with good oral hygiene. Cleaning index higher than 4 decreased the odds by about 85%. Oral hygiene habits, adjusted by salivary concentrations of selected inflammatory markers may allow predicting effectively overweight or obesity risk. Early proper dental prophylaxis and treatment could lead to the better prevention of metabolic disorders.

Validation and Application of a Derivatization-Free RP-HPLC-DAD Method for the Determination of Low Molecular Weight Salivary Metabolites

Saliva is an interesting, non-conventional, valuable diagnostic fluid. It can be collected using standardized sampling device; thus, its sampling is easy and non-invasive, it contains a variety of organic metabolites that reflect blood composition. The aim of this study was to validate a user-friendly method for the simultaneous determination of low molecular weight metabolites in saliva. We have optimized and validated a high throughput, direct, low-cost reversed phase liquid chromatographic method with diode array detection method without any pre- or post-column derivatization. We indexed salivary biomolecules in 35 whole non-stimulated saliva samples collected in 8 individuals in different days, including organic acids and amino acids and other carbonyl compounds. Among these, 16 whole saliva samples were collected by a single individual over three weeks before, during and after treatment with antibiotic in order to investigate the dynamics of metabolites. The concentrations of the metabolites were compared with the literature data. The multianalyte method here proposed requires a minimal sample handling and it is cost-effectiveness as it makes possible to analyze a high number of samples with basic instrumentation. The identification and quantitation of salivary metabolites may allow the definition of potential biomarkers for non-invasive "personal monitoring" during drug treatments, work out, or life habits over time.

Disease reciprocity between gingivitis and obesity

BACKGROUND

Many diseases seem to affect each other. This is particularly true of periodontal diseases that relate to many systemic diseases. For this reason, this study investigated the relationship between obesity and gingivitis in children by focusing on plasma and salivary metabolomic biochemicals.

METHODS

Whole saliva and plasma samples were taken from each of sixty-eight 11-year-old children afflicted by different degrees of both gingivitis and obesity. Gingivitis was evaluated as the percent of sites considered erythematous. Obesity was determined by waist circumference. Untargeted metabolomic analysis defined 29 biochemicals significantly correlated between saliva and plasma, which included the collagen breakdown amino acid hydroxyproline (Hyp). Two-sided t-tests and regression analysis were performed to compare these data from children with obesity alone, gingivitis alone, both, and neither.

RESULTS

Obese children exhibited signs of increased collagen turnover by being taller (14.4 cm) and having more permanent teeth (5.7). Analysis indicated a significant impact of obesity on gingivitis. Children with both diseases had 41.02% of gingival sites red whereas children with only obesity had 5.2% and children with only gingivitis had 19.16%. Hyp was increased in saliva by the combined presence of both diseases. The effects of gingivitis on obesity were in the same direction but generally not statistically significant.

CONCLUSION

Obesity clearly augments gingivitis. Data suggest that interaction between gingivitis and obesity may exhibit disease reciprocity in which activated neutrophils are mutually shared to create collagen destruction and Hyp release into both saliva and plasma.

Biochemical analysis of oral fluids for disease detection

The field of diagnostics using invasive blood testing represents the majority of diagnostic tests used as part of routine health monitoring. The relatively recent introduction of salivary diagnostics has lead to a major paradigm shift in diagnostic analyses. Additionally, in this era of big data, oral fluid testing has shown promising outcomes in a number of fields, particularly the areas of genomics, microbiomics, proteomics, metabolomics, and transcriptomics. Despite the analytical challenges involved in the interpretation of large datasets generated from biochemical studies involving bodily fluids, including saliva, many studies have identified novel oral biomarkers for diagnosing oral and systemic diseases. In this regard, oral biofluids, including saliva, gingival crevicular fluid (GCF), peri-implant crevicular fluid (PICF), dentinal tubular fluid (DTF), are now attracting increasing attention due to their important attributes, such as noninvasive sampling, easy handling, low cost, and more accurate diagnosis of oral diseases. Recently, the utilization of salivary diagnostics to evaluate systemic diseases and monitor general health has increased in popularity among clinicians. Saliva contains a wide range of protein, DNA and RNA biomarkers, which assist in the diagnosis of multiple diseases and conditions, including cancer, cardiovascular diseases (CVD), auto-immune and degenerative diseases, respiratory infections, oral diseases, and microbial (viral, bacterial and fungal) diseases. Moreover, due to its noninvasive nature and ease-of-adoption by children, it is now being used in mass screening programs, oral health-related studies and clinical trials in support of the development of therapeutic agents. The recent advent of highly sensitive technologies, such as next-generation sequencing, mass spectrometry, highly sensitives ELISAs, and homogeneous immunoassays, suggests that even small quantities of salivary biomarkers are able to be assayed accurately, providing opportunities for the development of many future diagnostic applications (including emerging technologies, such as point-of-care and rapid molecular technologies). The present article explores the omics and biochemical compositions of various oral biofluids with important value in diagnostics and monitoring.

Citrulline, A Potential Biomarker of Radiation-Induced Small Intestine Damage

Radiation damage assessment of the small intestine is important in nuclear accidents or routine radiotherapy of abdominal tumors. This article reviews the clinical symptoms and molecular mechanisms of radiation-induced small intestinal damage and summarizes recent research on biomarkers of such damage. Citrulline is the most promising biomarker for the evaluation of radiation-induced small intestinal damage caused by radiotherapy and nuclear accidents. This article also summarizes the factors influencing plasma citrulline measurement investigated in the latest research, as well as new findings on the concentration of citrulline in saliva and urine after different types of radiation.

Unstimulated Parotid Saliva Sampling in Juvenile Idiopathic Arthritis and Healthy Controls: A Proof-of-Concept Study on Biomarkers

The aims of this proof-of-concept study were to develop a collecting method for unstimulated parotid saliva in juvenile idiopathic arthritis (JIA) patients and healthy children and to investigate if inflammatory biomarkers could be detected in these samples. Forty-five children with JIA (median age of 12 years and 25th–75th percentile of 10–15 years; 33 girls and 12 boys) and 16 healthy children as controls (median age of 13 years and 25–75th percentile of 10–13 years; 11 girls and 5 boys) were enrolled in this study. Unstimulated parotid saliva was collected with a modified Carlson–Crittenden collector. The salivary flow rate and salivary concentrations of total protein and inflammatory mediators were assessed. The Meso Scale Discovery electrochemiluminescence immunoassay was used for analyzing protein concentrations and the inflammatory biomarkers. Sufficient parotid saliva volumes to be analyzed could be collected with the collection device. JIA patients had a lower sampling saliva volume (p = 0.008) and saliva flow rate (p = 0.039) than controls. The total protein concentrations and inflammatory biomarkers were measured in the last six healthy subjects. The median protein concentration was 1312 µg/mL (25th percentile: 844 µg/mL and 75th percentile: 2062 µg/mL; n = 6) and quantifiable concentrations of 39 inflammatory proteins could be assessed in these samples. In conclusion, this study indicates that the saliva sampling method, as used in the present study, is able to collect sufficient sample volumes in children, and that it is possible to analyze various inflammatory biomarkers in the collected saliva.

Late bedtime and dental caries incidence in Kuwaiti children: A longitudinal multilevel analysis

OBJECTIVE

Inadequate sleep contributes to several adverse systemic health outcomes due to hormonal and metabolic disorders. The purpose of this study was to determine the effect of bedtime on the development of dental caries and the relationship with salivary ghrelin and leptin in a prospective cohort study of Kuwaiti children.

METHODS

Data were collected from 5456 10-year-old children in 2012 and repeated in 2014. We selected children from 138 middle schools representing the six governorates of Kuwait. We derived data from oral examinations, self-reported sleep interviews, body and weight measurements, and chemical analysis of whole saliva samples. Leptin and ghrelin were determined by salivary assay in a subset of 744. Two separate analyses were performed. a) Using the entire longitudinal data set (n = 5456), multilevel random intercept analysis was conducted to assess the relationship between reported bedtime and dental caries. b) Using data from a subset of the original sample (n = 744), multiple linear regression analysis was conducted to determine the relationship between dental caries and salivary ghrelin and leptin. The outcome variable was the development of dental caries in children. The independent explanatory variables and confounders were bedtime, sleep duration, salivary ghrelin and leptin; confounders assessed were gingivitis, sex, age and governorate (school location).

RESULTS

With every additional hour past 8 pm for bedtime, there was a 20% increase in dental caries incidence over two years (B = 0.2, P = .01), adjusting for age, gender, gingivitis and governorate. There was a significant difference in the magnitude of dental caries between the six governorates of Kuwait. Lower levels of salivary leptin and higher levels of salivary ghrelin were associated with increased dental caries, and sleep duration was an effect modifier that negatively affected the relationship between leptin and dental caries (B = -0.09, P < .05) and positively affects the relationship between ghrelin and dental caries (B = 0.07, P < .05). Additionally, there was a significant clustering effect within schools in this cohort.

CONCLUSION

In a cohort study of Kuwaiti children, late bedtime was associated with increased dental caries incidence. Additionally, dental caries experience increased with higher levels of salivary ghrelin and lower levels of salivary leptin, and sleep duration mediates the relationship between these two biomarkers and dental caries.

Saliva Samples as A Tool to Study the Effect of Meal Timing on Metabolic And Inflammatory Biomarkers

Meal timing affects metabolic regulation in humans. Most studies use blood samples for their investigations. Saliva, although easily available and non-invasive, seems to be rarely used for chrononutritional studies. In this pilot study, we tested if saliva samples could be used to study the effect of timing of carbohydrate and fat intake on metabolic rhythms. In this cross-over trial, 29 nonobese men were randomized to two isocaloric 4-week diets: (1) carbohydrate-rich meals until 13:30 and high-fat meals between 16:30 and 22:00 or (2) the inverse order of meals. Stimulated saliva samples were collected every 4 h for 24 h at the end of each intervention, and levels of hormones and inflammatory biomarkers were assessed in saliva and blood. Cortisol, melatonin, resistin, adiponectin, interleukin-6 and MCP-1 demonstrated distinct diurnal variations, mirroring daytime reports in blood and showing significant correlations with blood levels. The rhythm patterns were similar for both diets, indicating that timing of carbohydrate and fat intake has a minimal effect on metabolic and inflammatory biomarkers in saliva. Our study revealed that saliva is a promising tool for the non-invasive assessment of metabolic rhythms in chrononutritional studies, but standardisation of sample collection is needed in out-of-lab studies.

Salivary Microbiological and Gingival Health Status Evaluation of Adolescents With Overweight and Obesity: A Cluster Analysis

Given the high prevalence of obesity in children and adolescents, the investigation of early markers is of clinical importance to better manage this condition. Thus, the aim was to evaluate the cross-sectional relationship between salivary microbiota, gingival health status, and excess weight in adolescents. A total of 248 students (14-17 y; 119 girls) were included, free of caries lesions and periodontal pockets. Physical examination included measures of height, weight, and body fat percentage (%BF). Oral examination was performed to gather information on dental (DMFT index) and gingival health status. Unstimulated saliva was submitted to qPCR reactions to quantify Streptococcus mutans, Porphyromonas gingivalis, Bifidobacteria, and Streptococcus pneumoniae percentages and the NFKappaB expression. Two-way ANOVA was applied considering group (normal-weight/overweight/obesity) and sex factors, in addition to cluster analysis. Group effect was significant for %S. mutans (partial eta² = 0.20; p < 0.001) and %Bifidobacteria (partial eta² = 0.19; p < 0.001), with overweight and obesity groups showing the highest levels compared to normal-weight ones, with no significant sex effect. There was no difference in the frequency of gingivitis, P. gingivalis, and S. pneumoniae percentages or NFKappaB expression between groups. Cluster analysis generated three clusters according to body fat accumulation: "Higher %BF," "Moderate %BF," and "Lower %BF." "Higher %BF" cluster was characterized by higher body fat percentage and higher salivary %Bifidobacteria, while cluster "Lower %BF" was characterized by lower body fat percentage and lower frequency of gingivitis ("Moderate %BF" cluster was the contrast). According to nutritional status, a difference in salivary S. mutans and Bifidobacteria percentages was found, with overweight or obesity adolescents showing the highest percentages than normal-weight ones. Besides, a positive relationship between body fat accumulation and Bifidobacteria count was observed, indicating a possible interaction between oral bacteria communities and weight gain.

The Clinical Utility of Salivary Biomarkers in the Identification of Type 2 Diabetes Risk and Metabolic Syndrome

Type 2 diabetes is traditionally diagnosed by the use of an oral glucose tolerance test and/or HbA1c, both of which require serum collection. Various biomarkers, which are measurable biological substances that provide clinical insight on disease state, have also been effective in the early identification and risk prediction of inflammatory diseases. Measuring biomarker concentrations has traditionally been obtained through serum collection as well. However, numerous biomarkers are detectable in saliva. Salivary analysis has more recently been introduced into research as a potential non-invasive, cost-effective diagnostic for the early identification of type 2 diabetes risk in adults and youth. Therefore, the purpose of this review was to compare 6 established inflammatory biomarkers of type 2 diabetes, in serum and saliva, and determine if similar diagnostic effectiveness is seen in saliva. A lack of standardized salivary analysis, processing, and collection accounts for errors and inconsistencies in conclusive data amongst studies. Proposing a national standardization in salivary analysis, coupled with increased data and research on the utility of saliva as a diagnostic, poses the potential for salivary analysis to be used in diagnostic settings.

Saliva as a non-invasive tool for assessment of metabolic and inflammatory biomarkers in children

BACKGROUND & AIMS

Epidemiological studies in school-age children are challenging, particularly those that aim to analyse metabolic markers on blood samples obtained via invasive and stressful procedures. The objective of this paper is to evaluate the use of saliva, as a non-invasive tool in epidemiological studies performed in school-age children, to capture metabolic changes associated with body mass index (BMI), dietary characteristics and physical activity in both boys and girls.

METHODS

This is an observational study in which healthy children of ages between 8 and 12 years (n = 129, 60 girls and 69 boys) from three schools in a Mediterranean area of Spain were included. A panel of biomarkers was measured in serum and saliva and correlated with BMI, dietary characteristics and physical activity.

RESULTS

Significant positive correlation between serum and salivary levels were detected for CRP (r = 0.770) in all included children, and boys (r = 0.805) and girls (r = 0.775) separately (P < 0.001, in all cases) and for insulin in girls (r = 0.442; P < 0.05). Among all studied salivary biomarkers, insulin was significantly correlated with the three factors studied: positively with BMI and negatively with dietary characteristics (intake and composition) and physical activity (P < 0.05). Obesity and diet composition were both positively associated to pro-inflammatory biomarkers, CRP and IL1b; while diet composition shared with physical activity levels the correlation with IL6 (positive with energy, fat, carbohydrate and saturated fatty acid intake, and negative with cholesterol intake and average physical activity in boys), NGF and glucose (in both cases correlations were negative with diet composition and physical activity variables) (P < 0.05, in all cases). Sex differences were detected in serum glucose and TNFα.

CONCLUSIONS

Biomarkers in saliva are able to capture differences in BMI, dietary characteristics and physical activity levels in school-age children. Saliva may potentially constitute a useful non-invasive and stress-free tool to evaluate metabolic markers of inflammation and/or metabolism related to BMI and lifestyle in a sex-dependent manner.

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.

Determining the biological associates of acute cold pressor post-encoding stress effects on human memory: The role of salivary interleukin-1β

Stress generally hurts many aspects of memory, but an interesting finding to emerge from the stress and memory literature is that stress that occurs shortly after learning (i.e., post-encoding stress) usually benefits memory. Although this effect is well established, the biological mechanisms underpinning this effect are not-especially in humans. We addressed this gap in the present study by collecting saliva samples from 80 participants who were randomized to a post-encoding stress (i.e., cold pressor for 3 min) or control task (i.e., warm water for 3 min) and 48 h later completed a recognition memory task. Saliva was collected both prior to and 15 min after the offset of (18 min after the onset of) the stress/control manipulation. Drawing on animal and human work, we examined how five stress-responsive biomarkers-cortisol, salivary α-amylase, progesterone, estradiol, and the proinflammatory cytokine interleukin (IL)-1β, all assessed in saliva-related to the effects of stress on memory. We found that stress enhanced recollection of negative images and that these effects were selectively related to salivary IL-1β. Moreover, we found that the beneficial effects of stress on memory were statistically mediated by salivary IL-1β. We found no robust associations-either linear or quadratic-between memory and any other biomarker, nor did we find significant interactions between biomarkers in predicting memory. These results suggest that immune system activity indexed by salivary IL-1β may play an important role in contributing to post-encoding stress effects on human memory.

The effect of educational and encouragement interventions on anthropometric characteristics, obestatin and adiponectin levels

BACKGROUND

Lifestyle modification is the most important strategy for control of obesity and overweight. Obestatin and adiponectin are the biomarkers of obesity. Thus, this study was performed to examine the effect of educational and encouragement interventions and lifestyle modifications on obesity anthropometric as well as obestatin and adiponectin levels.

METHODS

This semi-experimental study was conducted on a subsample of TABASSOM study. Participants were 41 overweight and obese children and adolescents aged 6-18 years old and 45 overweight and obese adults aged 19-65 years old. Anthropometric characteristics including height, weight, waist and hip circumferences, and body fat percentage (BFP) were measured at the first and after one year at the end of study. We implemented some educational and encouragement interventions regarding dietary modification and physical activity during the study. Obestatin and adiponectin levels were measured at the first and end of study by enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

The study did not show significant effect on anthropometric characteristics such as body mass index (BMI) and waist circumference (WC). BFP decreased significantly in boys, total children and adolescent group, and waist-to-hip ratio (WHR) decreased significantly only in adolescent boys after 1 year (P < 0.050).

CONCLUSION

Educational and encouraging interventions and lifestyle modifications could lead to decrease of body WHR and BFP in adolescent boys. This is helpful in controlling the increasing rate of obesity.

A new highly sensitive immunoassay for the detection of adiponectin in serum and saliva of dogs and its application in obesity and canine leishmaniosis

Adiponectin is an adipokine that exerts insulin-sensitizing and antiinflammatory properties. The aim of this study was to develop and validate a new heterologous ultrasensitive assay based on amplified luminescent technology for adiponectin determination in serum and saliva of dogs. A complete analytical validation of the assay was made in these fluids, and also this assay was applied to quantify adiponectin in serum and saliva of obese and lean dogs and dogs with leishmaniosis. These conditions were selected because in obesity there is a controversy about how adiponectin concentrations change in dogs, and in case of canine leishmaniosis, although it is described a decrease in serum adiponectin, there are not studies about how adiponectin changes after treatment. A total of 11 dogs were used in the validation and 26 dogs with different body condition and 8 with canine leishmaniosis were used for the clinical evaluation of the new assay for adiponectin quantification in serum and saliva of dogs. The analytical evaluation showed that the developed method could measure adiponectin in serum and saliva of dogs with high repeatability and sensitivity, adding a limit of quantification lower than commercially available ELISAs. In addition, significantly higher adiponectin concentrations were found in lean dogs and a correlation between serum and saliva was observed (P < .01). Moreover, dogs with leishmania presented reduced levels of adiponectin in serum. In conclusion, a new assay has been developed for adiponectin measurements which is more sensitive and faster than the traditional ELISA assays requiring less sample volume.

Association of salivary C-reactive protein with the obesity measures and markers in children

OBJECTIVE

Overweight and obesity is a pro-inflammatory state. This study aimed to examine the level of the salivary obesity markers in normal weight (NW) and overweight/obese (OW/OB) children, association with the obesity measures and the interrelations between the biomarkers.

SUBJECTS AND METHODS

Seventy-six children (40 normal weight and 36 overweight/obese) were recruited for this study. Body weight, height, and waist circumference measurement were obtained. The saliva sample was collected from all the participants. According to the Center for Disease Control and Prevention (CDC), the participants were classified into the normal weight or overweight/obese depending upon the body mass index (BMI) percentile ranking. The obesity panel of salivary markers resistin, C-C Motif Chemokine Ligand 2 (CCL2)/monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), complement factor D, and interleukin-10 (IL-10) were determined using human magnetic Luminex performance assay. The receiver operating characteristics (ROC) analysis was used to determine the area under the curve (AUC) to identify the best salivary biomarker in children. Linear regression and Pearson's correlation analyses to determine the association between the parameters.

RESULTS

The obesity biomarkers resistin, MCP-1, TNF-α, IL-6 and CRP were significantly high in overweight/obese compared to normal weight. Salivary CRP (AUC: 0.866, 95% CI: 0.780-0.952; p<0.0001) showed superiority area under ROC curves with good discriminatory power than resistin, MCP-1, TNF-α, and IL-6. BMI z-score, WC z-score, and WHtR z-score showed a significant association (p<0.0001) with CRP. The CRP significantly (p<0.0001) correlated with resistin, CCL2/MCP-1, TNF-α, IL-6, and IL-10 by linear regression and Pearson's correlation analysis.

CONCLUSION

Increased level of salivary CRP in children may be considered as a non-invasive marker for childhood obesity for detection of the risk factors for the development of metabolic dysregulation.

A Historical Review of Persian Medicine Studies into Saliva Manifestations for Potential Applications for Diagnosis and Management of Metabolic Syndrome

BACKGROUND AND OBJECTIVES

Regarding the development of diagnostic tests based on saliva and the prevalence of metabolic syndrome (MetS), the aim of this study is to review Persian Medicine manuscripts in the field of saliva manifestations, its relation to metabolic syndrome, and treatment recommendations.

METHODS

This study is a mini-review. We investigated the canon of medicine and some important Persian medical or pharmaceutical manuscripts from the 9th to the 19th centuries. PubMed and Google Scholar databases were explored for finding relevant information about the relationship between saliva and metabolic syndrome and its treatment.

RESULTS

Studies have suggested that maldigestion is one of the important causes of MetS. Sialorrhea may be an early symptom of maldigestion. Attention to sialorrhea and its treatment may be useful in the prevention and treatment of metabolic syndrome based on PM sources. In PM, sialorrhea is treated with 3 major approaches: lifestyle modification along with simple or compound medicines.

CONCLUSION

Saliva manifestations could be considered as early symptoms of metabolic syndrome. As mentioned in WHO strategies, traditional medicine can be used along with modern medicine due to its effectiveness in the management of various ailments.

Utility of hemoglobin A1c in detecting risk of type 2 diabetes: comparison of hemoglobin A1c with other biomarkers

We have previously reported that the risk of type 2 diabetes, early impaired glucose tolerance, and insulin resistance can be predicted using fasting levels of adiponectin, leptin, and insulin. Here, we aimed to evaluate the utility of hemoglobin A1c in detecting the risk of type 2 diabetes compared with other well-known biomarkers. We randomly enrolled 207 volunteers with no history of diseases, who underwent 75-g oral glucose tolerance tests and were stratified into normal, borderline, abnormal, or diabetic groups. Eighty-one participants with normal baseline levels of hemoglobin A1c (<6.0%) were included in the normal groups of both glucose tolerance and insulin resistance. Hemoglobin A1c was significantly correlated with the plasma glucose and insulin resistance index. Leptin, adiponectin, glycoalbumin, and body mass index also were correlated well with plasma glucose levels and insulin resistance index. Normal hemoglobin A1c levels with abnormal glucose tolerance and insulin resistance were noted in 85 and 67 participants, respectively. Hemoglobin A1c did not strengthen the prediction algorithm of diabetes, determined by our proposed biomarkers, leptin, adiponectin, and insulin. In conclusion, hemoglobin A1c is a surrogate biomarker for risk of diabetes, with inadequate predictive value, and should be used in combination with other biomarkers.

Dietary phosphorus enhances inflammatory response: A study of human gingivitis

Phosphates are associated with numerous disorders, ranging from vascular calcification to premature aging, possibly because of an increased inflammatory response. We therefore investigated the association of dietary phosphorus with gingivitis. We analyzed consumption of both phosphorus and sugar and related it to the concentrations of inflammatory biomarkers in saliva samples collected from 8314 children (mean age, 9.99 ± 0.68 years). About 64% of the children consumed more than 1250 mg phosphorus daily, and 34% consumed more than 82 g of sugar daily. Gingivitis was prevalent, with an average of 74% of possible gingival sites considered red. Quantile regression analysis revealed a statistically significant correlation between the occurrence of gingivitis and calorie-adjusted phosphorus intake and between gingivitis and calorie-adjusted sugar intake (both significant either as a linear trend or a categorical variable). In a subset (n = 744) investigation of nutrient consumption related to salivary biomarkers, we found that elevated calorie-adjusted phosphorus intake was directly associated with salivary IL-1β concentration (OR1.40, 95% CI 1.04-1.89), and inversely associated with salivary IL-4 concentration (OR0.62, 95% CI 0.46-0.84). Sugar intake was not significantly associated with either biomarker. Thus, elevated dietary phosphorus consumption may influence inflammatory disease by altering cytokine levels.

Salivary markers of hepato-metabolic comorbidities in pediatric obesity

BACKGROUND

The pediatric obesity epidemic calls for the noninvasive detection of individuals at higher risk of complications.

AIMS

To investigate the diagnostic role of combined salivary uric acid (UA), glucose and insulin levels to screen noninvasively for metabolic syndrome (MetS) and nonalcoholic fatty liver disease.

METHODS

Medical history, clinical, anthropometric, and laboratory data including serum triglyceride, glucose, insulin, HOMA, HDL-cholesterol, and UA levels of 23 obese children (15 with [St+] and 8 without [St-] ultrasonographic hepatic steatosis) and 18 normal weight controls were considered.

RESULTS

Serum and salivary UA (p < 0.05; R² = 0.51), insulin (p < 0.0001; R² = 0.79), and HOMA (p < 0.0001; R² = 0.79) levels were significantly correlated; however their values tended to be only slightly higher in the obese patients, predominately in [St+], than in the controls. Notably, UA and insulin levels in both fluids increased in parallel to the number of MetS components. After conversion of the z-logit function including salivary/anthropometric parameters in a stepwise logistic regression analysis, a factor of 0.5 allowed for predicting hepatic steatosis with high sensitivity, specificity, and total accuracy.

CONCLUSIONS

Salivary testing together with selected anthropometric parameters helps to identify noninvasively obese children with hepatic steatosis and/or having MetS components.

The salivary levels of leptin and interleukin-6 as potential inflammatory markers in children obesity

Background

Obesity among children is an alarming issue due to an increased incidence over the last years with devastating physiological and psychological consequences. Current available medical diagnostic tools use invasive methods to evaluate and monitor the lipid profile, glycaemia or liver status for determining the overweight/ obesity complications. The standard methods proposed for the assay of IL6 and leptin from saliva cannot detect these two biomarkers in children saliva; the levels of IL6 and leptin in children’s saliva are lower than the limit of determination of the standard methods. Therefore, we proposed a method based on utilization of stochastic sensors, able to simultaneously perform a qualitative and quantitative determination of these two biomarkers within minutes, in the range able to cover healthy and obese children.

Methods

Children from the urban area monitored for annual standard analyses and health status assessment at National Institute of Endocrinology C.I. Parhon within University of Medicine and Pharmacy “Carol Davila”, Bucharest, Romania were included in the study. In the same day, for all participants of the study, blood analyses were performed and saliva samples were collected for the determination of the IL-6 and leptin levels.

Findings/ Results

The children diagnosed with overweight/ obesity presented not significantly different blood lipid profile and glycaemia comparing to the control group. Only few cases of the children presented high levels of cholesterol, low level of HDL-cholesterol, a slightly increased level of triglycerides and transaminases. No correlation with the body mass index could be established with the blood analyses results. In case of the overweight/obese children, the salivary level of the proinflammatory citokynes IL-6 (41ng/mL±21) and leptin (40.4ng/mL±28.8), were significantly increased comparing to normal weight children (IL-6 8.1±4.6, leptin 9.58±3.1). Moreover, the saliva level of the IL-6 was positively correlated with the body mass index. Salivary leptin level was highly variable in case of obese children, 6 patients presenting similar levels with the control group.

Conclusions

Increased levels of salivary IL-6 and leptin sustain a systemic inflammation status despite normal range of standard blood analyses. The results were positively correlated in case of IL-6 with the body mass index the general accepted method used for the assessment of the obesity or overweight degree The determination of these markers in saliva samples by a stochastic method proved the utility within the medical examination for a better evaluation of the health status in obesity. The method has some advantages like: easy collection of the biological sample, fast determination of low concentrations and could be promising in case of no associated oral cavity infections or inflammations which could interfere the results.

Salivary C-reactive protein among at-risk adolescents: A methods investigation of out of range immunoassay data

Inflammatory markers including C-Reactive Protein (CRP) are increasingly used within research and clinical settings. Yet, varying methodologies for cleaning immunoassay data with out of range (OOR) samples may alter characteristic levels of CRP, thereby obscuring interpretation and reliability. This study investigated the influence of eight immunoassay OOR data treatment techniques on salivary CRP (sCRP) samples from at-risk adolescents. Participants from the 'Sleep and Education: learning New Skills Early' (SENSE) Study were 86 adolescents at-risk for depression (50 female), aged 14.29 years (SD = 1.04). ANOVA results showed no statistically significant differences in average morning (F(7, 590) = 1.24, p = .28) and evening (F(7, 599)=1.29, p = .25) values produced by each OOR data cleaning technique. However, varying techniques produced differences in the magnitude of Pearson's correlations between consecutive saliva samples (r's between 0.27-0.78), and influenced the significance of a sCRP diurnal pattern; two techniques produced statistically higher morning than evening sCRP levels (t(85) = 2.70, p = .01 and t(85) = 2.67, p = .01), whereas six techniques failed to find statistical differences between morning and evening sCRP levels (p's >.05). Varying techniques also produced statistically divergent associations between sCRP and age and depressive symptoms. Results from this study provide evidence for the temporal stability of sCRP among adolescents, show winsorization as an effective OOR data management technique, and highlight the influence of methodological decisions in cleaning salivary biomarker data and the need for consistency within the field.

Relationship of salivary adipocytokines, diet quality, physical activity, and nutrition status in adult Emirati females in United Arab Emirates

AIMS

The United Arab Emirates (UAE) ranks as the fifth most obese country with increasing cardio-metabolic risks. In this paper, relationships of salivary adipocytokines (markers of cardio-metabolic syndrome), diet quality and physical activity in 90 normal-weight, overweight and obese (30 subjects in each group) Emirati adult females were investigated.

METHODS

A cross-sectional research design was adopted. Anthropometric measurements, diet quality and physical activity questionnaires were administered. Overnight fasting saliva was collected to determine levels of adiponectin, interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-α).

RESULTS

Salivary adiponectin was significantly lower, while TNF-α was higher in obese than normal-weight subjects. IL-10 displayed a lower trend in obese subjects. Though diet quality and physical activity did not exhibit significant differences among the three groups, better diet quality and higher physical activity level were reported among normal-weight subjects. Salivary TNF-α correlated positively with body mass index (BMI) (r = 0.37; p < 0.001) and waist circumference (r = 0.31; p < 0.001), while adiponectin correlated negatively with BMI (r = -0.28; p < 0.05). IL-10 showed negative trend in correlation with obesity measures. Correlations were not observed between diet quality and physical activity with salivary adipocytokines. Interestingly, a significant negative correlation emerged between diet quality and neck circumference (r = -0.24; p < 0.05).

CONCLUSION

Our findings demonstrate that salivary adipocytokines correlate with obesity measures and can serve as convenient adjunct method in predicting cardio-metabolic risks in the population.

A Data Mining Approach Identified Salivary Biomarkers That Discriminate between Two Obesity Measures

BACKGROUND

A key mechanism of obesity involves dysregulation of metabolic and inflammatory markers. This study aimed to identify salivary biomarkers and other factors associated with obesity using an ensemble data mining approach.

METHODS

For a random cohort of over 700 subjects from 8137 Kuwait children (10.00 ± 0.67 years), four data mining methods were applied to identify important variables associated with obesity, including logistic regression by lasso regularization (Lasso), multivariate adaptive regression spline (MARS), random forests (RF), and boosting classification trees (BT). Each algorithm generated a variable importance rank list, based on an internal cross-validation procedure. An aggregated importance ranking was constructed by averaging the rank ordering of variables from individual list, weighted by the classification performance of respective models. Subsequently, the subset of top-ranking variables that were identified with at least three algorithms was evaluated by classification performance using receiver operating characteristic (ROC) analysis with bootstrap percentile resampling.

RESULTS

Obesity was defined either by the waist circumference (OBW) or by the body mass index (BMI) (OBWHO). We identified C-reactive protein (CRP), insulin, leptin, adiponectin, as salivary biomarkers associated with OBW, plus a clinical feature fitness level. A similar set of biomarkers was identified for OBWHO, but not including leptin. Tree-based clustering analysis revealed patterns that were significantly different between the OBW and OBWHO subjects.

CONCLUSION

A data mining approach based on multiple algorithms is useful for identifying factors associated with phenotypes, especially in cases where relationships are not salient, and a consensus from multiple methods can help produce a more generalizable subset of features. In this case, we have demonstrated that evaluation using the waist circumference includes association with high levels of salivary leptin, which is not seen with evaluation by BMI.

Glucose, fructosamine, and insulin measurements in saliva of dogs: variations after an experimental glucose administration

The aim of this study was to evaluate if glucose, fructosamine, and insulin levels can be measured in saliva of dogs and assess the changes in these compounds after an experimental glucose administration. Automated spectrophotometric assays for glucose and fructosamine and an ELISA assay for insulin measurements were validated in saliva of dogs, by evaluating precision, accuracy, and limits of detection. In addition, an intravenous glucose bolus was administrated to 10 beagles and fasting serum and saliva samples were obtained immediately before and 5, 10, 20, 30, and 45 min after glucose infusion. The results of the between-run imprecision gave mean CVs of 6.16, 9.40, and 3.10% for glucose, fructosamine, and insulin, respectively. Linearity under dilution showed coefficient of correlation of 0.999, 0.994, and 0.990 for glucose, fructosamine, and insulin, respectively. The LDs were 0.04 mg/dL, 4.08 μmol/L, and 0.02 μg/mL for glucose, fructosamine, and insulin, respectively. The glucose administration caused an increase in serum and salivary levels of glucose with a peak in salivary levels at 30 min and of insulin with a peak in salivary levels at 45 min, while fructosamine did not change. No correlations between serum and salivary concentrations were found for any compound. It is concluded that glucose, fructosamine, and insulin can be measured in saliva of dogs, and an experimental administration of glucose in this species can lead to increases in glucose and insulin in saliva.

Caveolin-1 Variant Is Associated With the Metabolic Syndrome in Kuwaiti Children

Caveolin-1 (CAV1) variants have been suggested to be associated with obesity and related metabolic disorders, but information based on human studies is limited. In the present study, we aimed to investigate the potential association between the CAV1 rs1997623 C/A variant and metabolic syndrome (MetS) in Kuwaiti children. DNA from saliva samples collected from 1313 Kuwaiti children (mean age: 12 years) were genotyped using the TaqMan SNP genotyping assay. The classification of MetS was based on the presence/absence of four indicators; (1) central obesity, (2) elevated systolic or diastolic blood pressure, (3) low salivary high-density lipoprotein cholesterol (HDLC), and (4) high salivary glucose. In this study, children with MetS scored ≥3, children in the intermediate metabolic group scored 1 or 2 and children without MetS scored 0. About one-third of the children were obese. A total of 246 children (18.7%) were classified as having MetS; 834 children (63.5%) were in the intermediate metabolic group, and 233 children (17.7%) had no indication of MetS. Obesity was highly prevalent in the MetS group (91.9%) while 26.8% of children were obese in the intermediate metabolic group. None of the children were obese in the group without MetS. Analysis of the CAV1 rs1997623 variant revealed a significant association of the A-allele (p = 0.01, Odds Ratio (OR) = 1.66) and the heterozygous CA-genotype (p = 0.005, OR = 1.88) with MetS. Consistently, the A-allele (p = 0.002, OR = 1.71) and CA-genotype (p = 0.005, OR = 1.70) also showed significant association with the intermediate metabolic group. Furthermore, the A-allele (p = 0.01, OR = 1.33) and the CA-genotype (p = 0.008, OR = 1.55) were associated with low levels of saliva HDLC. Individuals who were heterozygous or homozygous for the variant (CA/AA) showed significantly lower levels of high HDLC compared to those harboring the CC-genotype (p = 0.023). Our study revealed a novel association of the CAV1 rs1997623 variant with the MetS and with low saliva HDLC levels in young Kuwaiti children and indicated the need for further in-depth studies to unravel the role of CAV1 gene in the genetic etiology of MetS.

Saliva in the "Omics" era: A promising tool in paediatrics

In vulnerable populations, such as infants and children, saliva makes the perfect diagnostic medium because of its noninvasive collection, easy handling and storage of samples. Its unique biomarker profiles help tremendously in the diagnosis of many diseases and conditions. In fact, saliva genomics, proteomics, transcriptomics, metabolomics and microbiome-based discoveries have led to complementary and powerful diagnostic information. In children and neonates, saliva is the preferred medium not only for diagnosis of caries and aggressive periodontitis but also for a number of systemic conditions, metabolic diseases, cognitive functions, stress assessment and evaluation of immunological and inflammatory responses to vaccination. In this review, we provide an overview of current and future applications of saliva diagnostics to various diseases and conditions and highlight studies in paediatrics across the "omic" spectrum. Emerging frontiers in salivary diagnostics research that may significantly advance the field are also highlighted.