Acute phase protein and cytokine levels in serum and saliva: a comparison of detectable levels and correlations in a depressed and healthy adolescent sample

Blood cytokines in major depressive disorder in drug-naïve adolescents: A systematic review and meta-analysis

BACKGROUND

Major depressive disorder (MDD) is the most common mental health problem worldwide. Increased levels of inflammation are associated with MDD, though this relationship has been suggested to be bidirectional. The first incidence of a depressive episode usually occurs during adolescence. Hence, examining depressed, drug-naïve adolescents is important to understand the role of inflammation in the pathophysiology of MDD. Cytokines might play a crucial role in inflammation associated with MDD. Therefore, this article aims to investigate the changes in the levels of peripheral blood cytokines in adolescents with MDD.

METHODS

We conducted a systematic review and meta-analysis to assess the changes in peripheral blood cytokines in drug-naïve adolescents (10-18 years) with MDD. A comprehensive search across four databases was performed to identify original research articles. Studies in which the diagnosis of MDD was set by semi-structured interview were included.

RESULTS

Of 2291 articles, 12 met the inclusion criteria for the review, with seven suitable for meta-analysis & including up to five studies per cytokine. The meta-analysis revealed significant associations between tumor necrosis factor (TNF)-α (n = 222, Hedge's g = 0.51, p <0.01) and MDD in adolescents compared to healthy individuals. However, other blood cytokines, including interleukin (IL)-1β, IL-4, IL-6, IL-8, and interferon (IFN)-γ, did not significantly correlate with MDD in adolescents.

CONCLUSION

TNF-α was significantly elevated in drug-naïve adolescents with MDD. To further understand the role of TNF-α in MDD, a thorough investigation is required, taking into account the diversity, subtypes, chronicity, and severity of MDD.

Cytokines and Depressive Symptoms Among Adolescents

Background: Inflammation has been linked to an increased risk of depression, but there is limited and conflicting research on the role of inflammatory markers in adolescent depression. The purpose of this study was to examine associations between cytokines TNF-α, IL-1β, IL-6, and IL-8 and depression among a community-based sample of adolescents (13-19 years of age). Methods: Salivary samples were self-collected by adolescents for assay of cytokines. The Patient Health Questionnaire-9 (PHQ-9) was used to measure depressive symptoms and clinical depression, where a score ≥11 indicated the threshold for experiencing clinical depression. Multiple linear and logistic regression models were used to examine the relationships between cytokines and depression, adjusting for age, sex, ethnicity, income, and body mass index. Results: The mean age of the 83 participants was 15.86 years. Eight participants screened positive for depression; the mean depressive symptom score was 5.11. Higher levels of IL-6 (Coef = 1.33, p < .001) and IL-8 (Coef = 0.69, p = .025) were associated with more frequent depressive symptoms while higher levels of TNF-α (OR = 2.50, p = .002), IL-1β (OR = 1.98, p = .001), and IL-8 (OR = 2.44, p = .008) were associated with greater odds of meeting criteria for clinical depression. Conclusions: Future research should focus on factors that induce higher cytokine levels and the mechanisms underlying their effects on depression. Cytokines assessed in this study may ultimately have implications as methods for depression screening or targets for biologic interventions to prevent and treat adolescent depression.

Analysis of Salivary Cytokines in Retinopathy of Prematurity

BACKGROUND/OBJECTIVES

This cohort study aimed to establish a correlation between salivary cytokines and retinopathy of prematurity (ROP) in premature neonates. Additionally, we sought to identify a minimally invasive method for cytokine detection in this population.

METHODS

We recruited premature neonates born at less than 34 weeks gestational age (GA), with no history of maternal or neonatal infections. Salivary samples were collected on their first (D1) and seventh (D7) days of life, and cytokine levels were measured using the MILLPLEXMAP Human multiplex assay.

RESULTS

A total of 125 neonates were included in the study, categorized into two groups based on the severity of ROP: None to Mild and Moderate to Severe. The salivary levels of interleukin (IL)-6, IL-8, vascular endothelial growth factor (VEGF), and tumor necrosis factor (TNF)-α on D1 and D7 were significantly higher in the Moderate to Severe ROP group compared to the None to Mild ROP group (p = 0.005, 0.004, 0.026, 0.018, 0.001, 0.007, 0.025, and 0.002, respectively). After adjusting for GA, the levels of IL-6 and VEGF on D7 were significantly elevated in the Moderate to Severe ROP group compared to the None to Mild ROP group (p = 0.024 and 0.016, respectively).

CONCLUSIONS

This study establishes a novel, non-invasive method for the early prediction of ROP in premature neonates by correlating salivary cytokine levels in early life with the subsequent development of ROP.

Relation Between the Negative Cognitive Triad, Perceived Everyday Discrimination, Depressive Symptoms, and TNF-⍺ in Adolescents

Our study is guided by Beck's cognitive stress-vulnerability model of depression. We examined the associations between perceived everyday discrimination (PED) and TNF-⍺, an inflammatory biomarker associated with risk for severe illness, through the negative cognitive triad (NCT; negative thoughts about the self, world, and future) and depressive symptoms in adolescents. We utilized a sample of 99 adolescents (36.4% female; ages 13-16, M = 14.10, SD = 0.52) in our cross-sectional study. We used PROCESS and AMOS to compute regressions and direct, indirect, and total effects of PED, NCT aspects and depressive symptoms on TNF-⍺. Negative views of the self and world mediated between PED and depressive symptoms and that negative views of the self and future mediated between PED and TNF-⍺. In conclusion, Beck's theory can be expanded to physical health providing directions for addressing mental and physical health simultaneously by restructuring adolescents' negative view of the self.

Salivary IL-1 Beta Level Associated with Poor Sleep Quality in Children/Adolescents with Autism Spectrum Disorder

BACKGROUND

Sleep disorders are common in youths with autism spectrum disorders. Inflammatory cytokines such as Il-1 beta and Il-6 in saliva have been associated with alterations in sleep quality in various conditions. We assessed whether there were associations between the salivary concentration of IL-1 beta and IL-6 and sleep quality in youths with ASD versus typically developing (TD) age- and gender-matched youths.

METHOD

Forty children and adolescents with ASD or TD participated in this study (20% females). Their parents answered the items of a validated questionnaire on sleep quality (Pittsburgh Sleep Quality Index).

RESULTS

The mean Pittsburgh score was significantly higher (i.e., the quality of sleep was poorer) in the ASD group (8.68 ± 0.35 (SEM), ranging from 7 to 12 points), compared to the TD group (7.35 ± 0.54 (SEM), ranging from 2 to 12 points) (p = 0.02, Mann-Whitney U test). There were no significant differences in the salivary concentration of Il-1 beta and IL-6 receptor between the two groups, but salivary IL-1 beta concentration was inversely associated with poor sleep quality in the ASD group. No associations between the salivary Il-6 concentration and sleep quality were found in either group. Linear regression analysis by separate groups revealed significant associations between the sleep quality score and the concentration of IL-1 beta in the ASD group (p = 0.01, OR = -0.53, 95% CI -0.008-0.001). In contrast, no significant associations were observed in the TD group, or for IL-6 in either group. No significant effects of sex, age, or use of psychotropic medications were found.

CONCLUSIONS

Children and adolescents with ASD showed significantly poorer sleep quality based on their parents' reports compared to the TD group, and the salivary IL-1 beta concentration was inversely associated with sleep quality only in the ASD group. Further studies on the associations between inflammatory cytokines and sleep in ASD are needed.

Parotid saliva and blood biomarkers in juvenile idiopathic arthritis in relation to temporomandibular joint magnetic resonance imaging findings

BACKGROUND

Juvenile idiopathic arthritis (JIA) often affects the temporomandibular joint (TMJ) caused by an abnormal immune system that includes overactive inflammatory processes. Salivary biomarkers may be a powerful tool that can help establishing diagnosis, prognosis and monitor disease progress.

OBJECTIVE

The objective was to investigate biomarkers in parotid saliva and blood plasma in relation to temporomandibular joint (TMJ) magnetic resonance imaging (MRI) findings in patients with JIA and healthy individuals.

METHODS

Forty-five children aged 6 to 16 years with JIA and 16 healthy age- and sex-matched controls were included. Unstimulated parotid saliva samples and venous blood were collected. Biochemical analyses were performed for the cytokine biomarkers. The participants underwent MR imaging of the TMJs, where changes in the inflammatory and the damage domains were assessed.

RESULTS

In the JIA patients, lower concentrations of IL-6R and gp130 were found in parotid saliva than in plasma. Higher concentrations of IL-6 were found in parotid saliva than in plasma. IL-6, IL-6R and gp130 in parotid saliva explained the presence of bone marrow oedema and effusion in the JIA patients.

CONCLUSIONS

This study suggests that the IL-6 family in parotid saliva is associated with TMJ bone marrow oedema and effusion in patients with JIA, suggesting that IL-6 has promising properties as a parotid saliva biomarker for TMJ inflammatory activity.

Salivary concentrations of secretory leukocyte protease inhibitor and matrix metallopeptidase-9 following a single bout of exercise are associated with intensity and hydration status

AIM

To investigate the effects of exercise on salivary concentrations of inflammatory markers by analyzing a panel of 25 inflammatory markers in subjects who had participated in bicycle ergometer tests varying in workload and hydration status.

METHODS

Fifteen healthy young men (20-35 years) had performed 4 different exercise protocols of 1 hour duration in a randomly assigned cross-over design, preceded by a rest protocol. Individual workloads depended on participant's pre-assessed individual maximum workload (Wmax): rest (protocol 1), 70% Wmax in hydrated (protocol 2) and dehydrated (protocol 3) state, 50% Wmax (protocol 4) and intermittent 85%/55% Wmax in 2 min blocks (protocol 5). Saliva samples were collected before (T0) and immediately after exercise (T1), and at several time points after exercise (2 hours (T3), 3 hours (T4), 6 hours (T5) and 24 hours (T6)). Secretory Leukocyte Protease Inhibitor (SLPI), Matrix Metallopeptidase-9 (MMP-9) and lactoferrin was analyzed using a commercial ELISA kit, a panel of 22 cytokines and chemokines were analyzed using a commercial multiplex immunoassay. Data was analyzed using a multilevel mixed linear model, with multiple test correction.

RESULTS

Among a panel of 25 inflammatory markers, SLPI concentrations were significantly elevated immediately after exercise in all protocols compared to rest and higher concentrations reflected the intensity of exercise and hydration status. MMP-9 showed a significant increase in the 70% Wmax dehydrated, 50% Wmax and intermittent protocols.

CONCLUSIONS

Salivary concentrations of SLPI and MMP-9 seem associated with exercise intensity and hydration status and may offer non-invasive biomarkers to study (local) inflammatory responses to different exercise intensities in human studies.

Salivary biomarkers: novel noninvasive tools to diagnose chronic inflammation

Several chronic disorders including type 2 diabetes (T2D), obesity, heart disease and cancer are preceded by a state of chronic low-grade inflammation. Biomarkers for the early assessment of chronic disorders encompass acute phase proteins (APP), cytokines and chemokines, pro-inflammatory enzymes, lipids and oxidative stress mediators. These substances enter saliva through the blood flow and, in some cases, there is a close relation between their salivary and serum concentration. Saliva can be easily collected and stored with non-invasive and cost-saving procedures, and it is emerging the concept to use it for the detection of inflammatory biomarkers. To this purpose, the present review aims to discuss the advantages and challenges of using standard and cutting-edge techniques to discover salivary biomarkers which may be used in diagnosis/therapy of several chronic diseases with inflammatory consequences with the pursuit to possibly replace conventional paths with detectable soluble mediators in saliva. Specifically, the review describes the procedures used for saliva collection, the standard approaches for the measurement of salivary biomarkers and the novel methodological strategies such as biosensors to improve the quality of care for chronically affected patients.

Effects of filtration and alpha-amylase depletion on salivary biochemical composition measurements

The effects of filtration (F) and alpha-amylase depletion (AD) were assessed in n = 34 saliva samples. Each saliva sample was split into three aliquots and treated as follows: (1) no treatment; (2) 0.45μm commercial filter; and (3) 0.45μm commercial filter and affinity depletion of alpha-amylase. Then, a panel of biochemical biomarkers consisting of amylase, lipase, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), creatine kinase (CK), calcium, phosphorus, total protein, albumin, urea, creatinine, cholesterol, triglycerides, and uric acid was measured. Differences between the different aliquots were observed in all measured analytes. The most marked changes were found in triglycerides and lipase data for filtered samples, and in alpha-amylase, uric acid, triglycerides, creatinine, and calcium results in alpha-amylase-depleted aliquots. In conclusion, the salivary filtration and amylase depletion methods employed in this report caused significant changes in saliva composition measurements. Based on these results, it would be recommended to consider the possible effects of these treatments in salivary biomarkers when filtration or amylase depletion is performed.

Prospective study on Maresin-1 and cytokine levels in medication-naïve adolescents with first-episode major depressive disorder

Background

Inflammation and immune activation may play a role in the pathological mechanism of Major Depressive Disorder (MDD). Evidence from cross-sectional and longitudinal studies of adolescents and adults has shown that MDD is associated with increased plasma pro-inflammatory cytokines (e.g., IL-1β, IL-6). It has been reported that Specialized Pro-resolving Mediators (SPMs) mediate inflammation resolution, and Maresin-1 can activate the process of inflammation and promote inflammation resolution by promoting macrophage phagocytosis. However, no clinical studies have been conducted to evaluate the relationship between the levels of Maresin-1 and cytokine and the severity of MDD symptomatology in adolescents.

Methods

40 untreated adolescent patients with primary and moderate to severe MDD and 30 healthy participants as the healthy control (HC) group aged between 13 and 18 years old were enrolled. They received clinical and Hamilton Depression Rating Scale (HDRS-17) evaluation and then, blood samples were collected. Patients in the MDD group were re-evaluated for HDRS-17, and blood samples were taken after a six to eight-week fluoxetine treatment.

Results

The adolescent patients with MDD had lower serum levels of Maresin-1 and higher serum levels of interleukin 6 (IL-6) compared with the HC group. Fluoxetine treatment alleviated depressive symptoms in MDD adolescent patients, which was reflected by higher serum levels of Maresin-1 and IL-4 and lower HDRS-17 scores, serum levels of IL-6, and IL-1β. Moreover, the serum level of Maresin-1 was negatively correlated with the depression severity scores on the HDRS-17.

Conclusion

Adolescent patients with primary MDD had lower levels of Maresin-1 and higher levels of IL-6 compared with the HC group, implying that the peripheral level of pro-inflammatory cytokines may be elevated in MDD, resulting in the insufficiency of inflammation resolution. The Maresin-1 and IL-4 levels increased after anti-depressant treatment, whereas IL-6 and IL-1β levels decreased significantly. Moreover, Maresin-1 level negatively correlated with depression severity, suggesting that reduced levels of Maresin-1 promoted the progression of MDD.

The Link Between Positive and Negative Parenting Behaviors and Child Inflammation: A Systematic Review

Children's inflammation may be an important link between parenting behaviors and health outcomes. The aims of this systematic review were to: (1) describe associations between parenting behaviors and child inflammatory markers, and (2) evaluate the relevance of existing literature to the review question. Database searches identified 19 studies that included a measure of positive or negative parenting behaviors and a marker of child inflammation, 53% of which measured parental responsiveness/warmth. Greater parental responsiveness/warmth was associated with lower levels of child pro-inflammatory markers in 60% of studies. Across studies, the association between parenting and child inflammation varied as a function of parenting construct, inflammatory measure, and sample characteristics. Studies were highly relevant, with 42% rated 5 + out of 6 for study's ability to address links between parenting behavior and child inflammation. If future research uncovers causal effects of parenting behaviors on inflammation, parenting interventions could be employed as a preventative tool.

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.

Evaluation of Inflammatory Response System (IRS) and Compensatory Immune Response System (CIRS) in Adolescent Major Depression

Purpose

Nowadays, the role of two tightly interconnected systems, the inflammatory response system (IRS) and the compensatory immune response system (CIRS) in depression, is increasingly discussed. Various studies indicate pro-inflammatory activity in adolescent depression; however, there is an almost complete lack of findings about IRS and CIRS balance. Thus, we aimed to assess different IRS and CIRS indices, profiles, and IRS/CIRS ratios in drug-naïve MDD patients at adolescent age, with respect to sex.

Patients and Methods

One hundred MDD adolescents (40 boys, average age: 15.4±1.2 yrs.) and 60 controls (28 boys, average age: 15.3±1.5 yrs.) were examined. Evaluated parameters were 1. plasma levels of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, interferon gamma, tumor necrosis factor alpha (TNF-α), soluble receptor of IL-6 (sIL-6R), soluble receptors of TNF-α (sTNF-R1, sTNF-R2); 2. profiles: IL-6 trans-signaling, M1 macrophage signaling, helper T lymphocytes (Th) 1 profile, regulatory T lymphocytes (Treg)+Th2, allIRS, and allCIRS; 3. IRS vs CIRS activity ratios: TNF-α/TNF-R1, TNF-α/TNF-R2, TNF-α/sTNF-Rs (ie sTNF-R1+sTNF-R2), Th1/Th2, Th1/Treg, Th1/Th2+Treg, M1/Th2, M1/Treg, M1/Treg+Th2, allIRS/allCIRS.

Results

MDD patients showed increased IL-4, IL-10, TNF-α, sIL-6R, Treg+Th2, allIRS, allCIRS, and TNF-α/sTNF-Rs, and decreased Th1/Th2+Treg. MDD females showed increased IL-10 and TNF-α compared to control females. MDD males showed increased IL-4, IL-10, sIL-6R, Treg+Th2, and TNF-α/TNF-R1 compared to control males. Increased sTNF-R1 was found in MDD males compared to MDD females. Positive correlations were found between CDI score and sIL-6R and IL-10 in the total group and between CDI score and IL-10 in adolescent males.

Conclusion

Our study for the first time extensively evaluated IRS and CIRS interactions revealing enhanced pro-inflammatory TNF-α signaling and IL-6 trans-signaling in association with increased IL-10- and IL-4-mediated anti-inflammatory activity in first-episode depression at the adolescent age. Moreover, results reflect the sex-specific simultaneous activation of IRS and CIRS pathways in adolescent depression.

Pro-Inflammatory and Anti-Inflammatory Salivary Cytokines in Breast Cancer: Relationship with Clinicopathological Characteristics of the Tumor

The aim of the work was to compare the salivary cytokine profile of breast cancer patients with the clinicopathological characteristics of the tumor. The study included 113 patients with breast cancer (main group, mean age 54.1 years) and 111 patients with breast fibroadenomas (control group, mean age 56.7 years). Before treatment, saliva samples were collected from all patients and the content of cytokines (IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-18, MCP-1, and TNF-α) was determined. The content of cytokines in saliva correlates well with the clinicopathological characteristics of breast cancer. The level of all salivary cytokines increases at advanced stages of breast cancer and at a low degree of tumor differentiation. The exception is MCP-1, for which there is an extremely high content for well-differentiated breast cancer. A statistically significant increase in the content of MCP-1, IL-1β, IL-2, IL-4, and IL-10 was found in triple-negative breast cancer. For the first time, the correlation of salivary levels of TNF-α, IL-1β, and IL-6 with HER2 status, MCP-1, IL-1β, IL-2, and IL-4 with the hormonal status of the tumor was shown. The relationship between the level of IL-2, IL-10, and IL-18 in saliva with the level of Ki-67 expression has been established.

Salivary immune markers are not associated with self-reported childhood maltreatment or psychopathology in adults

BACKGROUND

Psychological stress has repeatedly been found to be associated with pro-inflammatory markers in blood, and neuro-inflammation may play a role in the development of psychopathology after early life stress. Salivary immune testing is a novel method to non-invasively assess immune functioning. We examined a large range of salivary immune markers in relation to self-reported childhood maltreatment and psychopathology in an adult sample.

METHODS

Participants (N = 118, 51% female, mean age = 46.6 yrs, range 22-64) were drawn from a cross-sectional three-generation study, and supplied 2 ml of saliva via passive drool. They reported on childhood maltreatment experiences and on psychopathological symptoms in the last 6 months. Hair cortisol was additionally assessed in a subsample (n = 68). Levels of IL1ß, IL6, IL8, IFNγ, TNFα, tIgE, sIgA, FLCƛ, and FLCƙ were assessed.

RESULTS

Linear mixed model analyses showed that several salivary immune markers were associated with age (sIgA and IgE), BMI (sIgA, IL1ß, and IL6), sex (FLCs and IgE), and bad health (IL6, IL8, TNFα). No associations with (anti-inflammatory) medication use or oral health problems were found. Notably, no associations between the immune markers and self-reported childhood maltreatment, psychopathology, or hair cortisol were found.

CONCLUSIONS

Salivary immune measures were found to be sensitive to individual differences in age, sex, health and BMI. However. in the current sample there was no indication of inflammation in relation to chronic psychological stress. Larger studies, including participants with higher stress levels, are needed to further examine associations between salivary immune markers and psychological stress.

Cytokine alterations in pediatric internalizing disorders: Systematic review and exploratory multi-variate meta-analysis

Pediatric internalizing disorders are prevalent and characterized by a maladaptive cognitive, emotional response to a perceived stressor. The hypothesized effect of this response is observable changes in behavior mediated by homeostatic inflammatory cytokines. The aim of this study was to synthesize the literature and analyze the effect of cytokines on pediatric internalizing disorders. Influential moderating variables, including mean body mass index, fasting status at blood collection, participant sex, cytokine type, mean age, percentage of sample medicated, and diagnosis, were also assessed. A systematic literature search was performed in electronic databases (Medline, PubMed, and PsycINFO) from January 1, 1980 to June 15, 2022. Case-control studies of pediatric internalizing disorders, specifically anxiety and depression, were reviewed for their association with peripheral cytokine levels. Meta-analyses were performed using a random effects multi-variate model and effect sizes were calculated using Hedge's g for IL-2, CRP, IL-6, TNF-α, IL-1β, IFN-γ, and IL-10. Thirty-three studies were reviewed and 28 studies were included in the meta-analysis (n = 1322 cases and n = 3617 controls). Peripheral cytokine levels were elevated in pediatric internalizing disorders compared to controls (Hedge's g = 0.19, p < 0.001). In the moderator analyses, depression diagnosis (Hedge's g = 0.18, p = 0.009) and non-fasting blood collection (Hedge's g = 0.20, p = 0.006) were significant. The meta-analytic findings are limited by methodological variation between studies, high heterogeneity, and low statistical power. Despite this, the findings suggest that elevated peripheral cytokine levels may play a role in the etiology and/or symptom maintenance of pediatric internalizing disorders.

Inflammatory Responses in Periodontitis with or Without Rheumatoid Arthritis Alter Salivary Metallothionein and Zinc

Periodontitis (PD) and rheumatoid arthritis (RA) are causally linked by their common inflammatory responses, yet it is largely unknown if these inflammatory responses might have an impact on salivary metallothionein (MT), zinc (Zn), and calcium (Ca) content. In this study, we analysed salivary concentrations of pro-inflammatory (IFN-γ, IL-6, and IL-17) and anti-inflammatory (IL-4 and IL-10) cytokines, as well as MT, Zn, and Ca in four groups of participants, namely control (without PD or RA, n = 21), PD (n = 21), RA (n = 21), or RAPD (n = 19). As expected, an increased amount of salivary pro-inflammatory cytokines were observed in the PD, RA, and RAPD groups. While Ca concentration was not significantly different between the groups, Zn concentration was lower in the PD, RA, and RAPD groups compared to the control group (p < 0.05). These groups also expressed higher MT/Zn ratios compared to the control group (p < 0.05). Unlike the control group, concentrations of inflammatory cytokines, MT, Zn, and Ca correlated with each other in the PD, RA, and RAPD groups (p < 0.05). Additionally, comorbidity of PD and RA appears to have a cumulative immuno-pathological impact that warrants further investigation. This study suggests that, in addition to inflammatory cytokines, salivary MT and Zn could reflect the severity of PD with or without RA, hence providing an important biomarker for diagnosis.

Longitudinal associations between salivary cortisol to C-reactive protein ratios and psychological well-being in Chinese adults

BACKGROUND

Salivary C-reactive protein (CRP) could be a viable biomarker of inflammation and has been associated with stress outcomes. The hypothalamic-pituitary-adrenal axis can modulate stress-related inflammation. This study aimed to evaluate the interaction effects of immune-endocrine markers on psychological outcomes.

METHODS

The study participants were 52 healthy Chinese adults who collected 10 saliva samples over 2 consecutive days at baseline. The participants completed validated measures on anxiety, depression, positive affect, and sleep disturbance at baseline and 1 month later. The stability and diurnal patterns of salivary cortisol and CRP were investigated via paired t-tests and repeated-measures analyses of variance. Regression analysis was used to examine the longitudinal associations between immune-endocrine markers and their interactions (cortisol [Cort]: morning CRP [CRP_morn] and Cort:CRP_even) and psychological measures.

RESULTS

Salivary cortisol and CRP displayed satisfactory stability over 2 consecutive days and diurnal patterns of abrupt and gradual decline during the day, respectively. Controlling for baseline psychological measures and confounding variables, Cort_morn and diurnal cortisol slope was significantly and negatively associated with anxiety symptoms and positive affect 1 month later, respectively. Cort:CRP_even and Cort:CRP_morn was significantly and positively associated with depressive symptoms and sleep disturbance 1 month later, respectively.

CONCLUSION

These findings offer initial support for the prognostic utility of salivary cortisol and CRP and their balance as determinants of psychological health in healthy adults.

Salivary Biomarkers as Predictors of Obesity and Intermediate Hyperglycemia in Adolescents

Introduction

Childhood obesity presents a major risk for metabolic diseases in adulthood. Noninvasive methods are needed for predicting the course of obesity in children and its complications. Using blood for longitudinal analyses of biomarkers to predict disease in children is not a convenient method. Saliva presents a noninvasive platform to detect inflammatory changes in biomarkers as possible predictive measures of future pathological events.

Objectives

The aim of this study was to evaluate the relationship between specific salivary biomarkers, obesity, and intermediate hyperglycemia in children. We also investigated the longitudinal association between the salivary biomarkers and change in Body Mass Index-for-age percentile scores (BMIz).

Methods

Data on 353 adolescents were collected from the individuals recruited for seven years in an ongoing Kuwait Healthy Life Study cohort. BMIz was measured at 10, 12, and 17 years of age. Interleukin (IL)-6, IL-8, IL-10, Leptin, C-Reactive Protein (CRP), Insulin, Vascular Endothelial Growth Factor (VEGF), and Monocyte Chemoattractant Protein-1 (MCP-1) were measured in saliva and serum. Additionally, fasting blood plasma glucose levels were recorded. Multilevel longitudinal regression modeling, mediation analyses, and logistic regression were used to determine the predictive value of salivary biomarkers in obesity and hyperglycemia.

Results

Longitudinal analyses showed that with each one-unit increase of salivary CRP and insulin, there was a 3.5 kg/m² and 3.2 kg/m² increase in BMIz, respectively. Comparable to serum CRP and insulin, higher salivary CRP and insulin OR 4.94 [95%CI: 1.66,14., OR 2.64 [95%CI: 1.09, 6.38], respectively) were predictive of hyperglycemia and obesity (OR 4.53 [95%CI: 2.40,8.50], OR 3.29 [95%CI: 1.82,5.97], respectively). Insulin was a strong mediator in the relationship between obesity and hyperglycemia.

Conclusion

Our findings demonstrated that salivary CRP and insulin were associated with hyperglycemia, obesity, and possibly diabetes in adolescents. Salivary biomarkers are a noninvasive approach with significant value for disease risk assessment and prevention.

Social support and C-reactive protein in a Québec population cohort of children and adolescents

Objective

Robust evidence exists for the health-enhancing benefits of social support in adults. Inflammatory processes are thought to be an important mechanism linking social support and health risk. Less is known about the relation between social support and chronic inflammation during childhood and adolescence, or when the association emerges during the lifespan.

Method

Data from the population-representative 1999 Quebec Child and Adolescent Health and Social (QCAHS) survey were analyzed. Youth aged 9, 13, and 16 years (N = 3613) and their parents answered questions about social support. A subsample (n = 2186) completed a fasting blood draw that was assayed for C-reactive protein (CRP).

Findings

Higher social support was significantly associated with lower hs-CRP_log, after controlling for age, sex, body mass index (BMI Z-score), medication use, puberty, ethnoracial status (French-Canadian), smoking, household income, and parental education (F = 25.88, p = < .001, Total R²_adj = 10.2%). The association was largely similar for boys and girls, and strengthened with age.

Conclusion

Greater social support was linked to lower chronic low-grade inflammation in a large sample of children and adolescents. Effect sizes were small and consistent with prior findings in the adult literature. Importantly, these findings provide evidence that the relation between social support and inflammation emerges early in the lifespan. Future work should consider broader, more encompassing conceptualizations of social support, the role of social media, and prospective trajectories of social support and inflammatory markers.

Lack of Evidence for a Relationship Between Salivary CRP and Women's Sexual Desire: An Investigation Across Clinical and Healthy Samples

BACKGROUND

Inflammation has been linked to a variety of mental and physical health outcomes that disproportionately impact women, and which can impair sexual function; thus, there is reason to expect a link between inflammation and women's sexual functioning.

AIM

To test the hypothesis that higher concentrations of C-reactive protein (CRP), a general biomarker of inflammation, would predict women's lower sexual desire.

METHOD

As 2 independent research teams, we conducted 3 separate studies (total n = 405) that assessed salivary CRP and various measurements of sexual desire in different women populations.

OUTCOMES

Female Sexual Function Index, Sexual Desire Inventory-2, Decreased Sexual Desire Screener, and Sexual Interest and Desire Inventory.

RESULTS

Regardless of the way sexual desire was measured (e.g., state vs trait; general desire vs. desire functioning) and the population sampled (i.e., healthy vs. clinically diagnosed with sexual dysfunction), all the studies revealed null results.

CLINICAL IMPLICATIONS

While exploratory, the convergence of these null results across studies and researchers suggests that if there is an association between inflammation and women's sexual desire, it is likely very subtle.

STRENGTHS & LIMITATIONS

Across 2 independent research teams, 3 unrelated studies, and various measurements of sexual desire, results were consistent. These points lend to the generalizability of the results. However, study designs were cross-sectional.

CONCLUSIONS

Future research may reveal (i) a non-linear threshold effect, such that inflammation does not begin to impact women's sexual desire until it is at a high level, (ii) inflammatory biomarkers other than CRP might be more sensitive in detecting associations between inflammation and desire, should they exist, or (iii) the mechanisms underlying sexual dysfunction may differ between sexes. Clephane K, et al. Lack of Evidence for a Relationship Between Salivary CRP and Women's Sexual Desire: An Investigation Across Clinical and Healthy Samples. J Sex Med 2022;19:745-760.

Are pro-inflammatory markers associated with psychological distress in a cross-sectional study of healthy adolescents 15-17 years of age? The Fit Futures study

Background

Inflammatory markers have been associated with depression and anxiety disorder in adolescents. Less is known about the association between inflammation and subclinical symptoms in the form of psychological distress. We investigated prevalence of psychological distress and examined the associations between common pro-inflammatory markers and psychological distress in an adolescent population sample.

Methods

The study was based on data from 458 girls and 473 boys aged 15–17 years from the Fit Futures Study, a large-scale study on adolescent health, conducted in Northern Norway. Psychological distress was measured with the Hopkins Symptom Checklist (HSCL-10). Serum-levels of the following low-grade inflammatory markers were measured: C-reactive protein (CRP), interleukin 6 (IL-6), transforming growth factor-alpha (TGF-α), tumor necrosis factor alpha variant 1 (TRANCE) and tumor necrosis factor alpha variant 2 (TWEAK). Associations between quartiles of inflammatory markers and HSCL-10 were examined by logistic regression and adjusted for potential confounders in sex-stratified analyses.

Results

The proportion of psychological distress above cutoff were 26.9% and 10.8% among girls and boys, respectively. In both girls and boys, crude analysis showed positive associations between all inflammatory markers and HSCL-10, except for TWEAK and TRANCE in boys. However, none of these associations were statistically significant. Further, there were no significant findings in the adjusted analyses.

Conclusion

There was a higher prevalence of psychological distress in girls compared to boys. Pro-inflammatory markers were not significantly associated with psychological distress in data from healthy adolescents aged 15–17 years.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40359-022-00779-8.

Association of childhood maltreatment history with salivary interleukin-6 diurnal patterns and C-reactive protein in healthy adults

Childhood maltreatment has been associated with increased inflammation, as indicated by elevated levels of proinflammatory markers such as interleukin-6 (IL-6) and C-reactive protein (CRP). Studies in humans show that secretion of IL-6 follows a clear circadian rhythm, implying that its disturbed rhythm represents an important aspect of dysregulated inflammatory system. However, possible alterations in diurnal secretion patterns of IL-6 associated with childhood maltreatment have not been studied. Here we investigated this association in 116 healthy adults. Diurnal levels of IL-6 were examined using saliva samples collected at 5 times a day across 2 consecutive days. Salivary CRP levels were also determined by averaging measurements at 2 times a day for 2 days. Different types of childhood maltreatment were assessed with the Childhood Trauma Questionnaire (CTQ). CTQ total and emotional abuse scores were significantly correlated with smaller IL-6 diurnal variation as indexed by lower standard deviation across the measurement times (p = 0.024 and p = 0.008, respectively). Individuals with emotional abuse, as defined by a cut-off score of CTQ, showed flatter IL-6 rhythm than those without (p = 0.031). These results, both correlation and group comparison, remained significant after controlling for age, sex, and body mass index. Childhood maltreatment was not associated with total output of IL-6 or CRP. Our findings indicate that childhood trauma can have a long-term negative effect on the circadian rhythm of inflammatory system. The findings are consistent with those of previous studies on adulthood trauma, suggesting that the disrupted IL-6 rhythmicity may be associated with a broad range of trauma-related conditions.

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.

Salivary IL-6 Concentration Is Associated with Frailty Syndrome in Older Individuals

Background: One of the physiological changes that is most closely associated with frailty is the increase in pro-inflammatory cytokines, and IL-6 in particular. Most studies have demonstrated this association using blood samples. We analyzed the relationship between frailty syndrome, individual frailty criteria, and IL-6 levels obtained by saliva tests. Methods: A cross-sectional pilot study was performed among women institutionalized in nursing homes. Frailty was defined as having three or more of the following components: low lean mass, weakness, self-reported exhaustion, low activity level, and slow walking speed; prefrailty was defined as having one or two of those components. Results: There was a significant and positive correlation between the frailty score and salivary IL-6 concentration. Regarding the associations between IL-6 and individual dichotomized frailty criteria, there were significant differences in salivary IL-6 concentration in two frailty criteria: weight loss (p = 0.002) and low physical activity (p = 0.007). Receiver operating characteristic curve analysis showed that IL-6 concentration significantly (p < 0.05) (although moderately) discriminated patients that progressed in the frailty syndrome (the area under the curve value was 0.697 with 95% CI 0.566–0.827). Conclusions: Salivary IL-6 concentration can be used as potential biomarker of frailty syndrome and as a tool to monitor the effects of interventions in frail individuals.

The Effects of a Single Bout of High- or Moderate-Intensity Yoga Exercise on Circulating Inflammatory Mediators: A Pilot Feasibility Study

Background

There is a knowledge gap in the physiological effects of short-term yoga exercise interventions.

Objective

To evaluate the feasibility of a randomized controlled trial (RCT) assessing the acute effects of a yoga exercise protocol practiced at 2 intensities (high or moderate) on temporal responses of a battery of systemic circulatory cytokines in healthy yoga-naïve adults.

Methods

This study was a three-arm, pre-post pilot-RCT employing a single bout of yoga exercise intervention. Groups were high-intensity yoga (HY, n = 10), moderate-intensity yoga (MY, n = 10), and a sedentary, no-intervention control group (CON, n = 10). Blood samples were collected at baseline and post-intervention at 6 timepoints (0-, 30-, 60-, 120-, 180-minutes, and 24-hours post-intervention) and were processed with a pre-defined inflammatory panel of 13 cytokines. Heart rate (HR) was assessed with a Polar H10^® device. The PROMIS Pain intensity Questionnaire was used to assess body soreness.

Results

We demonstrate feasibility of recruitment, randomization, and retention of participants based upon predetermined metrics, including: proportion of eligible to enrolled participants (55%); recruitment period (11-months); participant retention (97%); completion rate for questionnaires (99%); completion of physiological measures (98%); and adherence to the yoga exercise protocol (88%). Cytokine levels over time were heterogeneous within and between groups. Responses of a subset of cytokines were positively correlated with 1 another in high- and moderate-intensity yoga exercise groups but not in the control group. Median values for HR were 91 (IQR: 71-95) in the HY, 95 (IQR: 88-100) in the MY, and 73 (IQR: 72-75) in the CON. Pre-post changes in body soreness after the yoga exercise intervention were most evident in the HY group.

Conclusion

Along with observed trends in select cytokines, findings encourage a more definitive trial aimed at understanding the short-term effects of yoga exercise on inflammatory immune markers and pain in sedentary healthy adults. Clinicaltrials.gov ID# NCT04444102.

Inflammation and depression in young people: a systematic review and proposed inflammatory pathways

Depression onset peaks during adolescence and young adulthood. Current treatments are only moderately effective, driving the search for novel pathophysiological mechanisms underlying youth depression. Inflammatory dysregulation has been shown in adults with depression, however, less is known about inflammation in youth depression. This systematic review identified 109 studies examining the association between inflammation and youth depression and showed subtle evidence for inflammatory dysregulation in youth depression. Longitudinal studies support the bidirectional association between inflammation and depression in youth. We hypothesise multiple inflammatory pathways contributing to depression. More research is needed on anti-inflammatory treatments, potentially tailored to individual symptom profiles.

In(s) and out(s) of adolescent depression - Trajectories of development and recovery

While the role of biological markers in understanding major depressive disorder (MDD) in adults have been studied extensively, less has been done to identify the biomarkers of MDD development and recovery in adolescence. With the majority of mental health disorders starting in adolescence, identifying biomarkers of transition and recovery from MDD early in life is critical for developing effective prevention strategies. Considering most of the child and adolescent populations come from low-and-middle-income countries (LMICs), it is vital to focus on adolescent populations in these settings. With most studies coming from high-income countries (HICs), evidence suggests that elevated morning cortisol levels including cortisol awakening response (CAR), increased peripheral inflammation and brain abnormalities such as cortico-limbic dysregulation or blunted activity in reward related regions in response to positive information are associated with MDD and being at-risk for MDD development in adolescence. We also find that some of the biological mechanisms of recovery from MDD, mainly normalisation in the cortico-limbic dysregulation, are reported following psychological therapy, suggesting shared pathways leading to MDD vulnerability and recovery. Although, only a few studies include adolescent populations. Understanding molecular mechanisms through which psychological interventions are effective, as well as molecular markers of transition to depression in individuals at-risk, are important to inform effective prevention and intervention strategies.

Using mobile sensing data to assess stress: Associations with perceived and lifetime stress, mental health, sleep, and inflammation

Background

Although stress is a risk factor for mental and physical health problems, it can be difficult to assess, especially on a continual, non-invasive basis. Mobile sensing data, which are continuously collected from naturalistic smartphone use, may estimate exposure to acute and chronic stressors that have health-damaging effects. This initial validation study validated a mobile-sensing collection tool against assessments of perceived and lifetime stress, mental health, sleep duration, and inflammation.

Methods

Participants were 25 well-characterized healthy young adults (M_age = 20.64 years, SD = 2.74; 13 men, 12 women). We collected affective text language use with a custom smartphone keyboard. We assessed participants’ perceived and lifetime stress, depression and anxiety levels, sleep duration, and basal inflammatory activity (i.e. salivary C-reactive protein and interleukin-1β).

Results

Three measures of affective language (i.e. total positive words, total negative words, and total affective words) were strongly associated with lifetime stress exposure, and total negative words typed was related to fewer hours slept (all large effect sizes: r = 0.50 – 0.78). Total positive words, total negative words, and total affective words typed were also associated with higher perceived stress and lower salivary C-reactive protein levels (medium effect sizes; r = 0.22 – 0.32).

Conclusions

Data from this initial longitudinal validation study suggest that total and affective text use may be useful mobile sensing measures insofar as they are associated with several other stress, mental health, behavioral, and biological outcomes. This tool may thus help identify individuals at increased risk for stress-related health problems.

Cytokine concentrations in saliva vs. plasma at rest and in response to intense exercise in adolescent athletes

BACKGROUND

Salivary measures are advantageous in conducting large paediatric studies involving repeated measures. However, research measuring salivary cytokines in youth is limited.

AIM

Compare salivary with plasma concentrations of inflammatory cytokines at rest and following exercise in adolescent swimmers (21 male, 22 female).

METHODS

Following collection of resting saliva and blood samples, participants performed a bout of high-intensity interval swimming, with samples taken again ∼15 min post-swimming and analysed for interleukin-6 (IL-6), interleukin 10 (IL-10), and tumour necrosis factor-alpha (TNF-α).

RESULTS

Resting IL-10 was significantly lower, while IL-6 and TNF-α were significantly higher in saliva compared with plasma. IL-10 increased from pre- to post-swimming in plasma, but less so in saliva (51% vs. 29%; p = 0.02). TNF-α decreased post-swimming in saliva, but not in plasma (-27% vs -1%; p = 0.01). IL-6 decreased post-swimming in saliva compared with plasma (-21% vs. -3%; p = 0.06). Intraclass correlation coefficients (ICC) revealed no association between salivary and plasma IL-6 and TNF-α, while IL-10 showed a weak correlation only at rest (ICC = 0.39; p = 0.05).

CONCLUSIONS

Differences in concentrations and exercise responses, along with weak correlations, suggest that salivary cytokine levels are not an accurate representation of blood cytokine levels, and should not be used as a surrogate measure in paediatric studies.

Human Saliva as a Diagnostic Specimen for Early Detection of Inflammatory Biomarkers by Real-Time RT-PCR

Nowadays human saliva is more frequently studied as a non-invasive, stress-free, and preferable diagnostic material than blood. Supporting evidences acknowledge saliva as a mirror that reflects the body's physical state. Numerous studies have also demonstrated the presence and use of RNA derived from saliva in the early diagnosis of disease by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Assessing the host inflammatory response in patients and its resolution at an early stage can serve as a prognostic and predictive method in determining therapeutic response or disease progression. In this context, the potential of saliva as a specimen to diagnose early inflammatory biomarkers using RT-PCR seems fascinating and useful. Here, we review inflammatory biomarkers within the saliva, focusing on early detection of these biomarkers using RT-PCR and the factors influencing the quality of saliva specimen.

Biomarkers of Allostatic Load as Correlates of Impairment in Youth with Chronic Pain: An Initial Investigation

Pediatric chronic pain is common and responsible for significant healthcare burden. However, the mechanisms underlying the development and/or maintenance of pediatric chronic pain remain poorly understood. Allostatic load (AL), or wear and tear on the nervous system following significant or prolonged stress, has been proposed to play a role in the maintenance of chronic pain, but minimal research has examined this possibility. This gap in research is particularly notable given the high exposure to adverse childhood experiences (ACEs; abuse/neglect, etc.) and psychological stress in this population. Accordingly, the current study aimed to preliminarily examine the measurement of AL in a treatment-seeking pediatric pain population. Biomarkers were collected during an already scheduled new patient pain evaluation and included salivary cortisol, dehydroepiandrosterone (DHEA), and C-reactive protein, in addition to waist-hip ratio, body-mass index, and blood pressure. A total of 61 children and adolescents with chronic pain (Mage = 14.47 years; 88.5% female and white/Caucasian) completed study procedures and were included in analyses. Preliminary results indicated that a multifactorial AL composite is feasible to assess for in a tertiary pain treatment setting and that over 50% of youth with chronic pain were classified as high risk for AL (two or more risk factors). Further, it was found that individual AL risk factors were significantly associated with functional disability and that AL may moderate the association between psychosocial and functional outcomes. Given the pilot nature of this study, results should be used to inform future investigations with larger and more diverse pediatric pain samples.

Salivary C-reactive protein-a possible predictor of serum levels in pediatric acute respiratory illness

Identifying the etiology of an acute respiratory infection in children is a well-known challenge. In this study, we evaluated the correlation between salivary C-reactive protein (CRP) and its serum counterpart, which is known to be higher in bacterial infections but necessitates a venipuncture. Salivary and serum CRPs were measured in children with an acute respiratory illness, aged 2 months to 18 years. Pearson's correlation coefficients were used to measure correlation. Discrimination of the salivary CRP levels for predicting serum levels above 100 mg/L was calculated and compared to serum CRP levels. Sensitivity and specificity were similarly calculated. Salivary CRP was measured in 104 samples. Levels correlated significantly and positively with serum CRP levels (r = 0.670, p<0.001). Area under the curve for predicting serum CRP levels of 100 mg/L was 0.848. For a salivary CRP concentration above 32,610 ng/L, the sensitivity and specificity were 69% and 93%, respectively, for accurately predicting a serum CRP level ≥100 mg/L.Conclusions: Salivary CRP can be used in the pediatric acute setting due to its high specificity for predicting elevated serum levels without the need for venipuncture. Further studies are required to achieve higher sensitivity rates. What is known: • Salivary C-reactive protein has shown correlation to its serum counterpart, mainly in healthy children, adults, and ill neonates. What is new: • In a large population of children with acute respiratory illness, aged 2 months to 18 years, salivary C-reactive protein showed high specificity for predicting elevated serum levels, thus indicating its potential as a diagnostic tool.

Immunological Effects of an Add-On Physical Exercise Therapy in Depressed Adolescents and Its Interplay with Depression Severity

BACKGROUND

Pro-inflammatory cytokines (PICs) have gained attention in the pathophysiology and treatment of depressive disorders. At the same time, the therapeutic effect of physical activity seems to work via immunomodulatory pathways. The interventional study "Mood Vibes" analyzed the influence of exercise on depression severity (primary endpoint) in depressive adolescents; the influence of PICs on the clinical outcome was analyzed as a secondary endpoint.

METHODS

Clinically diagnosed depressed adolescents (N = 64; 28.1% male; mean age = 15.9; mean BMI = 24.6) were included and participated either in Whole Body Vibration (WBV) (n = 21) or bicycle ergometer training (n = 20) in addition to treatment-as-usual (TAU). Patients in the control treatment group received TAU only (n = 23). The PICs (interleukin-6-IL-6 and tumor necrosis factor-α-TNF-α) were analyzed before intervention, after 6 weeks of training (t1), and 8 weeks post-intervention (t2). The effects of the treatment on depression severity were rated by self-rating "Depression Inventory for Children and Adolescents" (DIKJ).

RESULTS

Basal IL-6 decreased in all groups from t0 to t1, but it increased again in WBV and controls at t2. TNF-α diminished in ergometer and controls from baseline to t1. PIC levels showed no correlation with depression severity at baseline. The influence on DIKJ scores over time was significant for IL-6 in the WBV group (p = 0.008). Sex had an impact on TNF-α (p < 0.001), with higher concentrations in male patients. Higher body mass index was associated with higher IL-6 concentrations over all measurement points (p < 0.001).

CONCLUSIONS

The positive effects of an intensive add-on exercise therapy on adolescent depression seem to be partly influenced by immunomodulation. A small sample size and non-randomized controls are limitations of this study.

Salivary cytokine - A non-invasive predictor for bronchopulmonary dysplasia in premature neonates

BACKGROUND

To find a less invasive method of cytokine detection for premature neonates, we conducted this cohort study to investigate the salivary cytokines and to analyze their correlations with bronchopulmonary dysplasia (BPD).

METHODS

Premature neonates younger than 34 weeks of gestational age without maternal or neonatal infection were recruited. Salivary samples were collected on their first (D1) and seventh (D7) days of life. The cytokine levels were detected by MILLPLEX® MAP Human multiplex assay. One-way analysis of variance, the Kruskal-Wallis test, Pearson's chi-square test, and logistic regression were used to analyze the data.

RESULTS

Totally 125 neonates were enrolled and separated into four groups: control, mild, moderate, and severe BPD group. The salivary levels of D1 interleukin (IL)-6, IL-8, IL-10, IL-17, interferon (IFN)-γ, and D7 IL-6 (p = 0.001, 0.001, 0.000, 0.043, 0.037 and 0.001, respectively) were significantly higher in the BPD groups than in the control group. After adjusting for the gestational age, acid-base equivalent, and absolute neutrophil count, comparing to the control group, the levels of D7 IL-17 became significantly lower in all three BPD groups (p = 0.032, 0.030, and 0.030, respectively) and that of D7 IFN-α2 became significantly lower in the severe BPD group (p = 0.037).

CONCLUSION

Early-life salivary cytokine levels were correlated with the development of BPD in premature neonates. This study provides a novel method to predict BPD early and non-invasively.

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.

Analysis of galectin-3 levels as a source of coronary heart disease risk during periodontitis

BACKGROUND AND OBJECTIVE

Different evidence has shown that Galectins have a key role as modulators of cell surface functions and signaling in a wide range of inflammatory diseases during their preclinical stages. The aim of this study was to analyze the association and impact of periodontitis and coronary heart disease (CHD) on salivary and serum Galectin-3 in patients with periodontitis and CHD.

MATERIALS AND METHODS

For the present study, healthy controls (n = 38), periodontitis (n = 40), CHD (n = 39), and a combination of periodontitis +CHD (n = 38) patients were enrolled and analyzed. In each patient, demographic characteristics and a full-mouth clinical periodontal examination were achieved. Moreover, serum and salivary samples were collected to assess Galectin-3 and Endothelin-1 (ET-1) levels. The Jonckheere-Terpstra p-trend and Spearman's correlation tests as well as uni- and linear regression analyses were used to analyze the study data.

RESULTS

Patients with periodontitis (serum, p = .003; saliva, p < .001) and periodontitis + CHD groups (serum p = .004; saliva, p < .001) had higher median serum and salivary concentrations of Galectin-3 in comparison with CHD and healthy controls. Serum (p = .006) and salivary (p = .009) Galectin-3 levels were significantly correlated with serum ET-1. The multivariate regression analysis highlighted that periodontitis (p = .047) was the significant predictor of serum Galectin-3 levels while ET-1 (p = .028) was the significant predictor of salivary Galectin-3 levels.

CONCLUSION

The results showed that patients with periodontitis and periodontitis + CHD presented significant higher serum and salivary Galectin-3 levels in comparison with CHD patients and healthy subjects. Periodontitis and ET-1 were the significant predictors of serum and salivary Galectin-3 levels, respectively.

Psychological symptoms and salivary inflammatory biomarkers in patients with dentofacial deformities: a case-control study

Individuals with dentofacial deformities often display a low quality of life (QoL) through biological mechanisms that remain unraveled. In this case–control study, the salivary levels of cytokines, glutamate, and kynurenine metabolites were assessed in patients undergoing orthognathic surgery (OS), while correlating these parameters with QoL and psychological symptoms. Thirty-six patients were enrolled in control (under orthodontic treatment) and test (undergoing OS) groups, matched by age and sex. The QoL was assessed through the World Health Organization Quality of Life BREF (WHOQOL-BREF) and the Orthognathic Quality of Life Questionnaire (OQLQ). The psychological symptoms were evaluated by the Satisfaction with Life Scale, the Rosenberg Self-Esteem Scale (RSES), and the Depression, Anxiety, and Stress Scale-21 (DASS-21). The salivary levels of IL-1β, IL-6, IL-10, glutamate, and kynurenine metabolites were evaluated. The OQLQ demonstrated increased QoL scores in the test group, regarding social aspects, facial esthetics, and function domains, without significant differences in respect to the other surveys. These patients displayed higher IL-1β and glutamate levels; conversely, the kynurenine metabolites were unaltered. The glutamate levels positively correlated with the OQLQ function scores. The data brings novel evidence about the psychobiological features of patients with dentofacial deformities, showing salivary variations of inflammatory biomarkers in these individuals.

Salivary cytokine cluster moderates the association between caregivers perceived stress and emotional functioning in youth

Some individuals exposed to early life stress show evidence of enhanced systemic inflammation and are at greater risk for psychopathology. In the current study, caregivers and their offspring (0-17 years) were recruited at a pediatric clinic visit at the University of California, San Francisco (UCSF). Mothers and seven-year-old children from the Growing Up inSingaporeTowards healthy Outcomes (GUSTO) prospective birth cohort were used as a replication cohort. Caregivers perceived stress was measured to determine potential intergenerational effects on the children's functioning and inflammation levels. Children's emotional functioning in the UCSF cohort was evaluated using the Pediatric Quality of Life (PedsQL) inventory. Child emotional and behavioral functioning was measured using the Child Behavior Checklist (CBCL) in GUSTO. Saliva was collected from the children and salivary levels of IL-6, IL-1β, IL-8 and TNF-α were measured using an electrochemiluminescent cytokine multiplex panel. Child IL-6, IL-1β, IL-8 cytokine levels were clustered into low, average, and high cytokine cluster groups using hierarchical cluster analysis. We did not find that salivary cytokine clusters were significantly associated with children's emotional or behavioral function. However, cytokine clusters did significantly moderate the association between increased caregiver perceived stress and reduced child emotional functioning (UCSF cohort) and increased Attention-Deficit-Hyperactivity (ADH) problems (GUSTO cohort, uncorrected Cohen's F2 = 0.02). Using a cytokine clustering technique may be useful in identifying those children exposed to increased caregiver perceived stress that are at risk of emotional and attention deficit hyperactivity problems.

Group singing improves both physical and psychological wellbeing in people with and without chronic health conditions: A narrative review

The aim of this narrative review was to establish a link between psychological and physical wellbeing in people with and without chronic health conditions who participated in group singing. Four databases were searched (PubMed, WoS, MEDLINE, and Scopus) using a systematic search method. Articles were screened, yielding 19 suitable articles. In most studies that were included group singing led to an increase in both psychological and physiological wellbeing. The major impacts were on affect and depression and anxiety.Group singing positively affects both physical and psychological wellbeing in people with and without chronic health conditions. No direction of causality could be established.

The intergenerational interplay of adversity on salivary inflammation in young children and caregivers

Systemic inflammation links exposure to early childhood adversity to later disease. The associations among adversity and disease risk might in part operate through poor oral hygiene and subsequent periodontal inflammation, which can be measured in saliva. Few studies, however, have examined the association between adversity and salivary inflammation in young children. Further, there is a dearth of literature investigating adverse experiences and salivary inflammation in children and caregivers together, limiting our understanding of the intergenerational, dual effects of adversity on inflammation for both members of the caregiver-child dyad. This study tested child and caregiver adversity and their associations with an inflammatory composite (i.e., IL-6, IL-1β, IL-8, TNF-α) and CRP in 93 preschool-age children and their caregivers. Caregivers reported on their child's experiences of adversity, as well as on their own adverse experiences, using a comprehensive questionnaire synthesized from previous checklists for complete coverage of possible adverse events. Results showed that caregivers' salivary inflammatory markers (i.e., IL-6, IL-1β, IL-8, TNF-α, and CRP) were not significantly correlated with the same five inflammatory markers in children's saliva. Among children, adversity was associated with significantly higher levels of the inflammatory composite, though not CRP. This association was amplified among children whose caregivers also experienced more adversity during adulthood. Among caregivers, childhood adversity and adulthood adversity were each independently associated with significantly higher levels of the inflammatory composite and CRP. The association between caregivers' own childhood adversity and inflammation was amplified among caregivers whose children also experienced more adversity during their childhoods. These findings provide preliminary evidence for the possible dual role of young children's and caregivers' adverse experiences in contributing to salivary inflammation for both members of the dyad, suggesting possible implications for systemic inflammation and future disease.

Plasma 25-Hydroxyvitamin D Concentrations and Serum and Salivary C-Reactive Protein in the Osteoporosis and Periodontal Disease Study

Vitamin D has been hypothesized to play an important role in preventing the development and progression of periodontal disease, but the underlying immune modulatory mechanisms remain understudied. We examined the cross-sectional association between biomarkers of vitamin D status and C-reactive protein (CRP) among postmenopausal women aged 53–81 years. Linear regression was used to examine the association between plasma 25-hydroxyvitamin D (25[OH]D) concentrations, a biomarker of vitamin D status, and both salivary and serum CRP concentrations in 567 women from the Buffalo Osteoporosis and Periodontal Disease (OsteoPerio) Study (1997–2000). CRP concentrations were measured with multiplex arrays and transformed for normality using the natural log. Concentrations above and below the limit of detection were included in analysis as right- and left-censored observations. An inverse association was observed between 25(OH)D and salivary CRP in a model adjusted for age, smoking status, frequency of tooth brushing and flossing, and hormone therapy use (−7.56% difference in salivary CRP concentrations per 10 nmol/L increase in 25(OH)D, 95% CI: −12.78 to −2.03). Further adjustment for percent body fat attenuated this association (−2.48%, 95% CI: −7.88 to 3.24). No significant associations were found between 25(OH)D and serum CRP. Plasma vitamin D concentrations were not associated with salivary or serum CRP concentrations in this cohort of postmenopausal women.

Anhedonia and Increased Evoked Immune Response

There is a growing body of evidence supporting the association between immune processes and psychopathology, including major depressive disorder (MDD). However, lack of diagnostic specificity has given rise to a search for specific symptom types, as opposed to more heterogeneous categorical diagnoses, linked to increased inflammation. One such symptom could be anhedonia, which is not only a key feature of MDD, but also a pervasive and persistent transdiagnostic symptom. To evaluate the specific role of anhedonia as well as categorical MDD diagnoses, we examined endotoxin-evoked immune responses in vitro in relation to current levels of anhedonia and history of recurrent MDD (rMDD) in a sample of adults recruited from the community. A total of 39 participants either had a history of rMDD (n ​= ​20) or no lifetime history of any MDD episodes (n ​= ​19). The average age of participants was 36.81 years and the majority were women (87.2%) and Caucasian (76.3%). We found that higher levels of current anhedonia, but not history of rMDD, were associated with increased lipopolysaccharide-stimulated levels of inflammatory markers even after we statistically adjusted for the potential influence of participants’ demographic (age, sex, ethnicity, income) and physiological (body temperature, BMI) characteristics, current symptoms of depression and anxiety, and the time of day of the sample collection. These findings highlight the relation of anhedonia specifically, rather than rMDD more generally, with inflammatory processes and identify endotoxin-stimulated cytokine production as a plausible biological marker of current anhedonia.

Effects of Eight-Week Combined Resistance and Endurance Training on Salivary Interleukin-12, Tumor Necrosis Factor, Cortisol, and Testosterone Levels in Patients with Breast Cancer

Background: In recent years, several studies have shown the association between exercise and decreased risk of mortality in patients with breast cancer. However, the effects of combined resistance and endurance training on salivary Interleukin-12 (IL-12), tumor necrosis factor (TNF-α), Cortisol, and Testosterone levels in patients with breast cancer have not been investigated. Objectives: This study aimed at determining the effect of 8 weeks of combined resistance and endurance training on salivary IL-12, TNF-α, Cortisol, and Testosterone levels in women with breast cancer. Methods: Forty-two postmenopausal women with breast cancer were randomly selected and divided into training (intervention) and control groups. The training group performed resistance training with 2 to 3 sets, 10 to 18 repetitions, 50 to 70% 1 repetition maximum (1RM), and aerobic exercise with 50 to 70% maximum heart rate (maxHR) (12-14 degrees borg scale) for 20 to 40 minutes for 8 weeks. The salivary IL-12, TNF-α, cortisol, and testosterone levels were measured, using the enzyme-linked immunosorbent assay (ELISA) method. Two-way analysis of variance repeated measure was also used to analyze variance with the confidence interval of 95%. Results: In the training group, there was a significant decrease in salivary TNF-α levels, cortisol, TNF-α/IL-12 ratio, and variables of weight, fat percentage, body mass index (BMI), and waist circumference (P < 0.05). Also, the results showed a significant increase in salivary testosterone and testosterone/cortisol ratio in the intervention group (P < 0.05). However, no significant changes were observed in the interaction between-group and time in IL-12 and waist–hip ratio (WHR) values (P > 0.05). Conclusions: The results indicate that resistance and endurance training could be used as a useful method to improve salivary pro-inflammatory factors and hormonal levels in patients with breast cancer. Medical oncologists can underline a resistance and endurance training program for patients with breast cancer under their care.

Salivary Inflammatory Molecules as Biomarkers of Sleep Alterations: A Scoping Review

Poor sleep quality and sleep disorders are the most common problems in people, affecting health-related quality of life. Various studies show an association between sleep disorders and altered levels of stress hormones and inflammatory cytokines measured in saliva. The main objective of this article is to provide an analysis of the current evidence related to changes in inflammatory markers in the saliva and their associations with sleep quality measurement (both objective and subjective methods) in healthy subjects and in sleep-related disorders. To that end, a scoping review was carried out, following the PRISMA criteria in the bibliographic search in several databases: PubMed, EBSCO, and SCOPUS. Eleven of the articles are from the adult population and two from the child-youth population. They mainly measure the relationship between sleep and interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNFα) alpha, as well as other inflammatory markers such as myeloperoxidase (MPO) and prostaglandin-endoperoxide synthase 2. An analysis shows the relationship between these salivary biomarkers and sleep quality, especially in the case of IL-6 in both healthy subjects and several pathologies associated with sleep-disorders. The results for TNFα and IL-1β measurements are still inconclusive and the difference with IL-6 was assessed. Two studies reported interventions that result in sleep improvement and are accompanied by the normalization of inflammatory changes detected in the saliva. As it is an easy-to-apply and non-invasive method, the measurement of salivary cytokines can be very useful in chronobiology studies. Further studies are required to determine the sensitivity of salivary inflammatory markers in monitoring biological rhythms and acting as biomarkers in the detection of sleep disorders and sleep interventions.

Peripheral Blood and Salivary Biomarkers of Blood-Brain Barrier Permeability and Neuronal Damage: Clinical and Applied Concepts

Within the neurovascular unit (NVU), the blood–brain barrier (BBB) operates as a key cerebrovascular interface, dynamically insulating the brain parenchyma from peripheral blood and compartments. Increased BBB permeability is clinically relevant for at least two reasons: it actively participates to the etiology of central nervous system (CNS) diseases, and it enables the diagnosis of neurological disorders based on the detection of CNS molecules in peripheral body fluids. In pathological conditions, a suite of glial, neuronal, and pericyte biomarkers can exit the brain reaching the peripheral blood and, after a process of filtration, may also appear in saliva or urine according to varying temporal trajectories. Here, we specifically examine the evidence in favor of or against the use of protein biomarkers of NVU damage and BBB permeability in traumatic head injury, including sport (sub)concussive impacts, seizure disorders, and neurodegenerative processes such as Alzheimer's disease. We further extend this analysis by focusing on the correlates of human extreme physiology applied to the NVU and its biomarkers. To this end, we report NVU changes after prolonged exercise, freediving, and gravitational stress, focusing on the presence of peripheral biomarkers in these conditions. The development of a biomarker toolkit will enable minimally invasive routines for the assessment of brain health in a broad spectrum of clinical, emergency, and sport settings.

Measuring salivary markers of inflammation in health research: A review of methodological considerations and best practices

There is an increasing interest in using saliva to measure inflammatory biomarkers. Compared to blood, saliva is non-invasive, requires a lower biosafety classification, and requires less specialized personnel to collect. As the assessment of inflammation in saliva becomes more popular in psychoneuroimmunology research, the development of gold-standard methodological practices is paramount. This paper reviews different considerations for designing studies to assess salivary measures of inflammation. We review saliva collection procedures, sample storage and processing considerations, assay techniques, flow rate, correspondence with blood-based markers, and potential demographic and health moderators of levels of salivary markers of inflammation. Together, this review highlights critical gaps for future research, including calls for standardization of study protocols, transparent reporting of results, assessing predictive validity of markers of salivary inflammation for disease, and the need for assessment of participants' oral and general health status. Although additional work is needed to elucidate gold standards for study design, measurement, and analysis, salivary markers of inflammation may be a useful tool for understanding oral and peripheral inflammation dynamics non-invasively.