The plasmatic and salivary levels of IL-1β, IL-18 and IL-6 are associated to emotional difference during stress in young male

Associations of the immune system in aggression traits and the role of microglia as mediators

There is an important relationship between the immune system and aggressive behavior. Aggressive encounters acutely increase the levels of proinflammatory cytokines, and there are positive correlations between aggressive traits and peripheral proinflammatory cytokines. Endotoxin lipopolysaccharide (LPS) treatment, which results in peripheral immune activation, decreases aggressive behavior as one of the sickness behavioral symptoms. In contrast, certain brain infections and chronic interferon treatment are associated with increased aggression. Indeed, the effects of proinflammatory cytokines on the brain in aggressive behavior are bidirectional, depending on the type and dose of cytokine, target brain region, and type of aggression. Some studies have suggested that microglial activation and neuroinflammation influence intermale aggression in rodent models. In addition, pathological conditions as well as physiological levels of cytokines produced by microglia play an important role in social and aggressive behavior in adult animals. Furthermore, microglial function in early development is necessary for the establishment of the social brain and the expression of juvenile social behaviors, including play fighting. Overall, this review discusses the important link between the immune system and aggressive traits and the role of microglia as mediators of this link.

Hybrid Integration of Wearable Devices for Physiological Monitoring

Wearable devices can provide timely, user-friendly, non- or minimally invasive, and continuous monitoring of human health. Recently, multidisciplinary scientific communities have made significant progress regarding fully integrated wearable devices such as sweat wearable sensors, saliva sensors, and wound sensors. However, the translation of these wearables into markets has been slow due to several reasons associated with the poor system-level performance of integrated wearables. The wearability consideration for wearable devices compromises many properties of the wearables. Besides, the limited power capacity of wearables hinders continuous monitoring for extended duration. Furthermore, peak-power operations for intensive computations can quickly create thermal issues in the compact form factor that interfere with wearability and sensor operations. Moreover, wearable devices are constantly subjected to environmental, mechanical, chemical, and electrical interferences and variables that can invalidate the collected data. This generates the need for sophisticated data analytics to contextually identify, include, and exclude data points per multisensor fusion to enable accurate data interpretation. This review synthesizes the challenges surrounding the wearable device integration from three aspects in terms of hardware, energy, and data, focuses on a discussion about hybrid integration of wearable devices, and seeks to provide comprehensive guidance for designing fully functional and stable wearable devices.

Immune response and intergroup bias: Vaccine-induced increases in cytokine activity are associated with worse evaluations of resume for Latina job applicant

Situational factors can increase people's vulnerability to intergroup bias, including prejudicial attitudes, negative stereotyping, and discrimination. We proposed that increases in inflammatory activity that coincide with acute illness may represent a hitherto unstudied situational factor that increases intergroup bias. The current study experimentally manipulated increases in inflammatory activity by administering the seasonal influenza vaccine or a saline placebo. We quantified inflammatory activity by assessing change in salivary pro-inflammatory cytokines and assessed intergroup bias using a resume evaluation task and self-reported ethnocentrism. Primary analyses focused on a subsample of 117 participants who provided high quality data; robustness analyses included various permutations of lower quality participants. Findings revealed that changes in the cytokine interleukin-1β (IL-1β) in response to the vaccine were associated with greater intergroup bias. Among participants who received the vaccine, IL-1β change was negatively associated with evaluation of a Latina (but not a White woman) applicant's competency and recommended starting salary. Moreover, IL-1β change was positively associated with ethnocentrism. Overall, results provide support for the hypothesis that acute illness, via the mechanistic role of inflammatory cytokines, affects social cognition in ways that can increase intergroup bias.

A study protocol for risk stratification in children with concussion (RSiCC): Theoretical framework, design, and methods

Research shows that one in five children will experience a concussion by age 16. Compared to adults, children experience longer and more severe postconcussive symptoms (PCS), with severity and duration varying considerably among children and complicating management of these patients. Persistent PCS can result in increased school absenteeism, social isolation, and psychological distress. Although early PCS diagnosis and access to evidence-based interventions are strongly linked to positive health and academic outcomes, symptom severity and duration are not fully explained by acute post-injury symptoms. Prior research has focused on the role of neuroinflammation in mediating PCS and associated fatigue; however relationship between inflammatory biomarkers and PCS severity, has not examined longitudinally. To identify which children are at high risk for persistent PCS and poor health, academic, and social outcomes, research tracking PCS trajectories and describing school-based impacts across the entire first year postinjury is critically needed. This study will 1) define novel PCS trajectory typologies in a racially/ethnically diverse population of 500 children with concussion (11-17 years, near equal distribution by sex), 2) identify associations between these typologies and patterns of inflammatory biomarkers and genetic variants, 3) develop a risk stratification model to identify children at risk for persistent PCS; and 4) gain unique insights and describe PCS impact, including fatigue, on longer-term academic and social outcomes. We will be the first to use NIH's symptom science model and patient-reported outcomes to explore the patterns of fatigue and other physical, cognitive, psychological, emotional and academic responses to concussion in children over a full year. Our model will enable clinicians and educators to identify children most at risk for poor long-term health, social, and academic outcomes after concussion. This work is critical to meeting our long-term goal of developing personalized concussion symptom-management strategies to improve outcomes and reduce disparities in the health and quality of life of children.

The diagnostic value of salivary C-reactive protein in neonatal infections: a meta-analysis

PURPOSE

C-reactive protein (CRP), as an acute phase protein, is a sensitive indicator of neonatal bacterial infection. Some recent studies have shown that there is a correlation between CRP levels in serum and saliva, and using saliva to detect CRP levels is expected to be an ideal and non-invasive method to predict neonatal infection. The purpose of this Meta-analysis was to evaluate the diagnostic value of salivary CRP for neonatal infection.

METHODS

We searched PubMed, Embase, Web of Science, and Scopus databases in October 2023 and included observational studies that examined salivary CRP in newborns with bacterial infections. Data was extracted regarding the methodology, participant characteristics, and outcome measures.

RESULTS

Nine articles were included, with a total of 696 newborns. Salivary CRP levels are significantly higher in neonates with infections compared to non-infected group (SMD = 0.58, 95%CI [0.40-0.76], P < 0.001). The accuracy for salivary CRP to predict serum CRP abnormality is high (sensitivity 86%, specificity 88%, area under the curve = 0.94).

CONCLUSIONS

Our meta-analysis suggested that salivary CRP can be used as an alternative biomarker to serum CRP for detecting neonatal infection.

Salivary CRP predicts treatment response to virtual reality exposure therapy for social anxiety disorder

BACKGROUND

Social anxiety disorder (SAD) places a profound burden on public health and individual wellbeing. Systemic inflammation may be important to the onset and maintenance of SAD, and anti-inflammatory treatments have shown promise in relieving symptoms of SAD. In the present study, we conducted secondary analyses on data from a randomized clinical trial to determine whether C-reactive protein (CRP) concentrations and social anxiety symptoms decreased over the course of virtual reality exposure therapy, and whether changes in social anxiety symptoms as a function of treatment varied as a function of CRP.

METHOD

Adult participants (N = 78) with a diagnosis of SAD (59 % female) were randomized to receive exposure therapy alone, or exposure therapy supplemented with scopolamine. Social anxiety symptoms, salivary CRP, and subjective units of distress were measured across three exposure therapy sessions, at a post-treatment extinction retest, and at a 1-month follow-up.

RESULTS

CRP decreased over the course of treatment, b = -0.03 (SE = 0.01), p =.02 95 %CI [-0.06, -0.004], as did all social anxiety symptom domains and subjective distress. Higher CRP was associated with greater decreases from pre-treatment to 1-month follow-up in fear, b = -0.45 (SE = 0.15), p =.004 95 %CI [-0.74, -0.15], and avoidance, b = -0.62 (SE = 0.19), p =.002 95 %CI [-1.01, -0.23], and in-session subjective distress from pre-treatment to post-treatment, b = -0.42 (SE = 0.21), p =.05 95 %CI [-0.83, -0.001]. However, declines in CRP were not correlated with declines in fear, r = -0.07, p =.61, or avoidance, r = -0.10, p =.49, within-persons.

CONCLUSIONS

Virtual reality exposure therapy may be associated with an improvement in systemic inflammation in patients with severe SAD. Pre-treatment CRP may also be of value in predicting which patients stand to benefit the most from this treatment.

Salivary inflammatory burden in pre- and postmenopausal women: Associations with body mass index, patient-reported health, serum cytokines, and periodontal parameters

BACKGROUND

The decline of estrogen levels during menopause impacts weight, mood, and overall health, both orally and systemically. This study assessed salivary levels of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), IL-10, and IL-7 in postmenopausal (PMW) and regularly menstruating premenopausal (RMPW) women, while considering serum cytokine levels, body mass index (BMI), periodontal health, and self-reported physical and emotional well-being.

METHODS

In this study, 75 PMW and 71 RMPW were included. Clinical and periodontal parameters were evaluated, and perceived health was assessed with the Women's Health Questionnaire (WHQ). Cytokine levels in both saliva and serum were quantified by enzyme-linked immunosorbent assay (ELISA). Covariate evaluations of salivary cytokines were conducted using hierarchical linear regression modeling.

RESULTS

Cytokines were detectable in saliva from 71 PMW and 67 RMPW. In the initial unadjusted model, IL-7, IL-10, and TNF-α exibited significant differences between RMPW and PMW. However, these differences became non-significant (p > 0.05) in the final model after adjusting for age, which implies a negligible effect of the investigated covariates on salivary cytokine levels when age was considered. Lower levels of IL-6 in PMW, which initially showed no significant difference, became borderline (p = 0.054) in the final model after adjusting for age.

CONCLUSIONS

After adjusting for multiple factors, no significant difference was found in the salivary levels of the investigated cytokines between RMPW and PMW. Factors such as BMI, perceived health, serum cytokine levels, and periodontal parameters seem to minimally influence these levels in PMW. However, age may be a stronger confounding factor.

Variation in maternal lactation practices associated with changes in diurnal maternal inflammation

While the importance of human milk in shaping infant immune function is well established, the impact of at-the-nipple (ATN) breastfeeding on maternal immune status has been understudied. Since lactation evolved to support infant survival and boost maternal fitness, we predict that ATN breastfeeding will confer benefits on maternal immune function. We measure the absolute and relative frequency of different infant feeding methods (ATN breastfeeding, pumping, donated milk, other supplementation) used by postpartum women in Seattle, WA (USA). We implement Bayesian modeling to estimate the effects of ATN breastfeeding on diurnal change in secretion rate of "pro-inflammatory" salivary cytokines and C-reactive protein (CRP). Our results show that most mothers in our sample used a variety of infant feeding methods, with pumping as the most common alternative to ATN breastfeeding. We find that ATN breastfeeding is associated with non-linear effects on diurnal IL-8 and CRP. Furthermore, we find that women who report zero versus ubiquitous ATN breastfeeding exhibit opposing diurnal patterns in CRP secretion rate. This study provides evidence that variation in maternal lactation practices corresponds to differences in maternal immune responses, highlighting how measuring lactation as a continuous variable can further enhance understanding of postpartum maternal physiology.

Salivary Interleukin 1-Beta Concentration Associates With Sleep Quality in Older Individuals

Background: Poor sleep quality is prevalent in older people and impairs their quality of life. Various studies show an association between sleep disorders and altered levels of inflammatory cytokines. The cytokine IL-1β has been shown to display both somnogenic and insomnia-promoting effects in experimental animals. Objectives: to evaluate the relationship between insomnia and salivary IL-1β concentration and the role of associated factors such as the symptoms of depression, use of hypnotics, intake of caffeinated beverages, smoking, and alcohol use in older individuals. An analytical, cross-sectional, observational research was carried out with a population of community-dwelling individuals over 60 years of age in Valencia (Spain). Sleep quality was measured with the Athens insomnia scale (AIS) and depressive symptoms with Geriatric Depression Scale (GDS). Results: 287 individuals participated in the study (mean age 74.08 years (76.7% women). 41.5% of the participants had insomnia, 36.9% took drugs for sleep problems, and 32.4% had relevant depressive symptoms. There was a significant inverse correlation between the IL-1β and total AIS score (rho = -0.302, p < 0.001), the sleep difficulty subdomain (rho = -0.259, p < 0.001), and the daytime sleepiness subdomain (rho = -0.322, p < 0.001). No significant correlation was observed between GDS and salivary IL-1β concentration. The IL-1β concentration was significantly lower in individuals taking drugs for sleeping compared with those not taking those drugs (1.11 ± 0.09 and 1.48 ± 0.08, respectively; p = 0.001). Regarding the AIS score, there was no significant difference in marital status, smoking, or the number of cups of tea or cola drinks, but there was a significant association with alcohol intake (p = 0.019) and in the number of daily intakes of coffee (p = 0.030). The receiver operating characteristic (ROC) curve analysis of IL-1β for diagnosis of moderate-severe insomnia showed an area under the curve (AUC) value of 0.78 (95% confidence interval 0.71-0.85). At the cut-off of 0.83 pg/µL of Il-1β, it had a sensitivity of 70.3% and a specificity of 69.8%.

Testosterone:cortisol ratio as a predictor of podium in adolescent rowing athletes

Purpose

There is a lack of data regarding the stress and motivation response in adolescent athletes during competitions. The athletic performance can be highly influenced by stress rather than appropriate training, at this age. The aim of this investigation is to evaluate the level of stress markers in adolescent rowers in different competition settings that might alter their stress status and performance.

Methods

Adolescent rowing athletes (12-18 yrs) have been tested for determining saliva content of stress biomarkers, cortisol and testosterone, before and after competitions that have been performed indoor and outdoor. Specifically, samples have been taken in the morning, before and after the race in 2 different settings: 1) an indoor rowing competition with an ergometer, 2) an outdoor rowing competition on boats.

Results

A reduction in cortisol levels has been observed in athletes right before the outdoor race, while testosterone levels increased at the same time point before either the ergometer or boat competition and kept rising at the end of the race. Significant differences have been found comparing the testosterone/cortisol ratio between indoor and outdoor data, being higher in the indoor race at all considered time-point. Furthermore, the linear regression demonstrated that the increased ratio correlated with a better podium position in the indoor race.

Conclusion

Despite the age differences among athletes might have an influence on their hormone levels, these data suggest that rowing athletes subjected to different kind of competitions show a different stress and motivation response profile that might influence their performance.

Increased Salivary IL-1 Beta Level Is Associated with Poor Sleep Quality in University Students

Poor sleep quality is a major public health concern for all ages. In particular, university students often face stress levels and changes in social life habits that negatively influence their quality of sleep. This could be associated with psychological well-being in terms of anxiety and depressive symptoms, stress levels, and a poor self-perceived health status. The increases in the pro-inflammatory cytokine interleukin 6 (IL-6), IL-1 beta (IL-1β), and tumor necrosis factor alpha (TNFα), in blood have been linked to poor sleep quality in many diseases, but data on salivary cytokine levels in students are missing or are seldom analyzed. In this study we determined the quality of sleep in a sample of university students and the role of psychological assessment and factors affecting sleep (alcohol intake, tobacco, consumption of stimulant drinks, exercise, and body mass index). We also aimed to shed new light on the associations between sleep quality and salivary inflammatory cytokines (IL-1β, IL-6, and TNFα). Sleep quality was measured with the Athens Insomnia Scale (AIS) and Pittsburgh Sleep Quality Index (PSQI). Perceived stress was assessed using Cohen's Perceived Stress Scale (PSS), and the Goldberg Anxiety and Depression Scale (GADS) was used to assess the level of anxiety or depression. Perceived health status was measured with a visual analogue. Saliva samples was taken in the morning and the inflammatory cytokines was measured via enzyme-linked immunoassay. There was a direct and significant association between the salivary IL-1β concentration and AIS score (r = 0.248; p = 0.038, Pearson correlation) and Pittsburgh scale score (r = 0.274; p = 0.022, Pearson correlation). The relationship between IL-1β and AIS controlling for sex, age, and chronic disease, is still significant (r = 0.260; p = 0.033). The relationship between IL-1β and PSQI controlling for the influence of these variables is also significant (r = 0.279; p = 0.022). Salivary IL-1β concentrations were not significantly associated with any of the scores of the other psychological assessments (PSS, anxiety, depression symptoms, or self-perceived health). Salivary TNFα was significantly and inversely associated with self-perceived health (r = -0.259; p = 0.033, Pearson correlation), but the salivary IL-6 concentration was not associated with any of the sleep quality scale or psychological assessment scores. Our results provide a novel relationship between pro-inflammatory cytokine IL-1β in saliva and poor sleep quality. However, the role of inflammation in poor sleep quality requires further study to identify strategies that could lower inflammation and thus, likely improve sleep quality.

Assessment of temporomandibular disorders and their relationship with life quality and salivary biomarkers in patients with dentofacial deformities: A clinical observational study

A close relationship between dentofacial deformities (DFD) and temporomandibular disorders (TMD) has been suggested, which might impact the quality of life (QoL) and psychological aspects. We evaluated the presence of TMD in DFD patients, correlating these findings with QoL and salivary levels of biochemical markers of pain and psychological disorders. The study enrolled 51 patients, which were distributed into three groups: (i) orthodontic, (ii) TMD, and (iii) DFD. TMD diagnosis was conducted according to Axis I and II of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). QoL was evaluated by the Oral Health Impact Profile (OHIP-14). The salivary levels of interleukin-1β (IL-1β) were determined by ELISA, while glutamate and serotonin amounts were evaluated by mass spectroscopy. DFD individuals had a positive diagnosis for TMD, as indicated by the Axis I (DC/TMD). They exhibited poorer outcomes regarding pain, functional, and psychological dimensions, according to the Axis II DC-TMD. The QoL evaluation demonstrated poorer outcomes for DFD individuals, accompanied by greater IL-1β salivary contents. Notably, glutamate levels had a positive correlation with behavioral parameters in Axis II DC-TMD, with a mild relevance for serotonin. DFD patients display chronic myofascial pain featuring TMD, with altered psychological symptoms and poor QoL, encompassing changes in pain mediators. Data bring new evidence about the relevance of TMD in DFD patients, which likely impacts the QoL and the salivary levels of biochemical markers of functional, painful, and psychological disorders.

Neuroendocrine response to a psychosocial stress test is not related to schizotypy but cortisol elevation predicts inflexibility of semantic memory retrieval

An altered stress response can contribute to the transition from preclinical psychotic symptoms to the clinical manifestation of schizophrenia and other psychotic disorders. The present study was aimed at testing the hypotheses that (i) the autonomic and neuroendocrine responses under psychosocial stress are dysregulated in individuals with high psychosis proneness (schizotypy); (ii) the magnitude of post-stress autonomic activation and cortisol release predicts alterations in semantic memory retrieval. The study was performed in 73 healthy individuals of both sexes with either high or low schizotypal traits preselected out of 609 individuals using the Schizotypal Personality Questionnaire. A psychosocial stress procedure based on public speech was used as a stress model. We found that individuals with high schizotypy engaged in less adaptive emotional stress-coping strategies than low schizotypy individuals. Yet, the neuroendocrine, immune, and sympathetic activation in response to the stress test was not different between the groups. Irrespective of the exposure to the stressor, individuals with high schizotypy were less fluent when retrieving associations from semantic memory. In addition, we demonstrated that acute psychosocial stress reduced the flexibility of semantic memory retrieval. The post-stress mental inflexibility was reliably predicted by the concomitant elevation of cortisol concentrations in saliva. The present study thus brings novel evidence indicating that the acute psychosocial challenge impairs retrieval flexibility in the semantic domain, which may be due to neuroendocrine activation.

Detection of Periodontal Disease Marker with Geometrical Transformation of Ag Nanoplates

Alkaline phosphatase (ALP) and interleukin-1beta (IL-1β) are crucial salivary biomarkers for the diagnosis of periodontal disease that harms the periodontal tissue along with tooth loss. However, there has been no way of sensitive and portable detection of both biomarkers in saliva with multivariate signal readout. In this work, we design the multicolorimetric ALP and IL-1β sensing platform based on geometrical transformation of silver nanoplate transducer. By utilizing enzymatic activity of ALP that dephosphorylates p-aminophenol phosphate (p-APP) to p-aminophenol (p-AP), localized surface plasmon resonance properties of silver nanoplate vary with ALP and show a distinct color change from blue to yellow based on a controlled seed transformation from triangular to hexagonal, rounded pentagonal, and spherical shape. The multicolor sensor shows an ALP detection range of 0-25 U/L with a limit of detection (LOD) of 0.0011 U/L, which is the lowest range of LOD demonstrated to date for state-of-the-art ALP sensor. Furthermore, we integrate the sensor with the conventional ELISA to detect IL-1β for multicolor signaling and it exhibits a linear detection range of 0-250 pg/mL and an LOD of 0.066 pg/mL, which is 2 orders of magnitude lower than the monochromic conventional ELISA (LOD of 3.8 pg/mL). The ALP multicolor sensor shows high selectivity with a recovery of 100.9% in real human saliva proving its reliability and suitability for the readily accessible periodontal diagnosis with multivariate signal readout.

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.

The Potential Prognostic, Diagnostic and Therapeutic Targets for Recurrent Arrhythmias in Patients with Coronary Restenosis and Reocclusions After Coronary Stenting

BACKGROUND

The interplay of oxidative stress, proinflammatory microparticles, and proinflammatory cytokines in recurrent arrhythmias is unknown in elderly patients with coronary restenosis and reocclusions after coronary stenting.

OBJECTIVE

This research sought to investigate the potential diagnostic and therapeutic targets for recurrent arrhythmias in patients with coronary restenosis and reocclusions after coronary stenting.

METHODS

We examined whether oxidative stress, proinflammatory microparticles, and proinflammatory cytokines could have effects that lead to recurrent arrhythmias in elderly patients with coronary restenosis and reocclusions. We measured the levels of malondialdehyde (MDA), CD31 + endothelial microparticle (CD31 EMP), CD62E + endothelial microparticle (CD62E + EMP), high-sensitivity C-reactive protein (hs-CRP), interleukin- 1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α), as well as oxidized low-density lipoprotein (OX-LDL), and assessed the effects of relationship between oxidative stress, proinflammatory microparticles, and proinflammatory cytokines on recurrent atrial and ventricular arrhythmias in elderly patients with coronary restenosis and reocclusions after coronary stenting.

RESULTS

The levels of CD31 + EMP, CD62E + EMP, MDA, hs-CRP, IL-1β, IL-6, IL-8, TNF-α and OX-LDL were found to be increased significantly in coronary restenosis + recurrent atrial arrhythmia group compared to without coronary restenosis and coronary restenosis + without recurrent atrial arrhythmia groups, respectively (P < 0.001). Patients in the coronary reocclusion + recurrent ventricular arrhythmia group also exhibited significantly increased levels of CD31 + EMP, CD62E + EMP, MDA, hs-CRP, IL-1β, IL-6, IL-8, TNF-α and OXLDL compared to without coronary reocclusion and coronary reocclusion + without recurrent ventricular arrhythmia groups, respectively (P < 0.001).

CONCLUSION

Proinflammatory microparticles, proinflammatory cytokines, and oxidative stress might act as potential targets for recurrent arrhythmias in patients with coronary restenosis and reocclusions after coronary stenting.

Salivary Diagnostic for Monitoring Strenuous Exercise-A Pilot Study in a Cohort of Male Ultramarathon Runners

Intense physical stress, such as that in ultramarathon running, affects the immune system. For monitoring in sports medicine, non-invasive methods, e.g., salivary analysis, are of interest. This pilot cohort study aimed to assess changes in salivary parameters in response to an ultramarathon. The results were compared to blood parameters. Male, healthy finishers (n = 9, mean age: 48 ± 8.8 years, mean height: 1.8 ± 0.1 m, mean weight: 72.5 ± 7.2 kg, mean BMI: 23.5 ± 1.9 kg/cm²) of a 160 km ultramarathon were included. Saliva and blood samples were collected at three time points: T1 (baseline), T2 (shortly after the ultramarathon) and T3 (after recovery). In saliva, cortisol, testosterone, IL-1β, IL-6, IL-8, IL-10, TNF-α, albumin, IgA, α-amylase, aMMP-8, and neopterin were assessed via ELISA. In blood, cortisol, testosterone, IL-1β, IL-6, IL-8, IL-10, TNF-α, blood cell counts, procalcitonin, CRP, osmolality, albumin, and α-amylase were analyzed. The statistical evaluation comprised longitudinal testing and cross-sectional testing between saliva and blood using ratios of T2 and T3 to baseline values. Various parameters in saliva and blood changed in response to the ultramarathon. Comparing blood and saliva, the longitudinal changes of testosterone (p = 0.02) and α-amylase (p = 0.03) differed significantly. Despite the limitations of the study, it underlines that saliva is an interesting option for comprehensive monitoring in sports medicine and necessitates further studies.

Validation of a novel method of ultraviolet-induced cutaneous inflammation and its associations with anhedonia

Affective immunology of the skin is a growing area; however, established protocols for measuring individual differences in cutaneous inflammation are lacking. To address this, we present a preliminary validation of Precision Implementation of Minimal Erythema Dose (PI-MED) testing as a method for measuring cutaneous inflammation. PI-MED is a recently adapted protocol, optimized for reproducibility and individual differences research, that uses ultraviolet (UV) light to evoke cutaneous erythema, or inflammatory skin reddening. PI-MED's novel UV dosage schedule produces standardized erythema responses across different skin pigmentation types and shows strong internal consistency within person and good test-retest reliability across 8-10 weeks. In line with predictions, increased PI-MED erythema was associated with heightened anhedonia, across several measures, beyond influences of non-affective covariates. While future work should further refine the dosage schedule for the lightest and darkest skin types, overall, evidence supports PI-MED as a protocol for inducing and measuring individual differences in cutaneous inflammation. Further, PI-MED-induced erythema can expand psychoneuroimmunology research by offering a complementary assessment for general inflammatory tone. This work adds to a growing body of evidence demonstrating a distinct relationship between inflammation and anhedonia.

Association of sugar-sweetened beverages with executive function in autistic children

The association between sugar-sweetened beverages (SSBs) consumption and executive function (EF) among typically developing (TD) children has been investigated in previous studies but with inconsistent results. Furthermore, this relationship has been less investigated among autistic children who perform worse in EF compared with TD children. In this study, we aimed to investigate the association between SSB consumption and EF in autistic children, and whether the association between SSB and EF in autistic children is different from that in TD children. We recruited 106 autistic children and 207 TD children aged 6–12 years in Guangzhou, China. Children’s EF was assessed by using the Chinese version of parent-reported Behavior Rating Inventory of Executive Function, Stroop Color–Word Test, and working memory subscales of the Chinese version of Wechsler Intelligence Scale for children, Fourth edition. Meanwhile, we assessed children’s dietary intake and SSB consumption with a validated Food Frequency Questionnaire. In this study, 70 (66.0%) autistic children consumed SSB and 20 (18.9%) of them consumed more than two servings SSB a week. Among autistic children, over two servings per week SSB consumption was associated with poorer performance in emotional control [β = 7.20, 95% confidence interval (CI): 0.94–13.46] and plan/Organize (β = 6.45, 95% CI: 0.27–12.63). The association between over two servings/week SSB consumption and emotional control among autistic children was significantly different from that among TD children (β_ASD = 7.20; β_TD = −3.09, Z = 2.72, p = 0.006). Results of this study show that SSB consumption was associated with an impairment in some subscales of EF in autistic children. Furthermore, the association between SSB and EF in autistic children might be different from that in TD children.

Gastrointestinal tract-based implicit measures for cognition, emotion and behavior

Implicit physiological measures such as heart rate and skin conductance convey information about someone's cognitive or affective state. Currently, gastrointestinal (GI) tract-based markers are not yet considered while both the organs involved as well as the microbiota populating the GI tract are bidirectionally connected to the brain and have a relation to emotion, cognition and behavior. This makes GI tract-based measures relevant and interesting, especially because the relation may be causal, and because they have a different timescale than current physiological measures. This perspective paper (1) presents the (mechanistic) involvement of the GI tract and its microbiota in emotion, cognition and behavior; (2) explores the added value of microbiome-based implicit measures as complementary to existing measures; and (3) sets the priorities to move forward. Five potential measures are proposed and discussed in more detail: bowel movement, short-chain fatty acids, tyrosine and tryptophan, GI tract flora composition, and cytokine levels. We conclude (1) that the involvement of the GI tract in emotion, cognition and behavior is undisputed, (2) that GI tract-based implicit measures are still in a conceptual phase of development but show potential and (3) that the first step to bring this field forward is to start validation studies in healthy humans and that are designed in the context of implicit measurements.

Alterations in serum IL-6 levels in traumatized pediatric patients: A preliminary study for second hit concept

BACKGROUND

The inflammatory response of pediatric patients to multiple injuries can be monitored by serum interleukin-6 levels. The aim of this study was to investigate the severity of the inflammatory response accordingly interleukin-6 (IL-6) which have not been evaluated before.

METHODS

There were 30 patients with an isolated long-bone fracture in group 1 and 49 patients with multi-system injury with at least a fracture in group-2. In group-2 were divided into two subgroups according to MISS (cut-off value = 17). Group-3 was composed of 100 healthy children as the control group to determine the normal range of serum IL-6 levels. In group-2, blood samples were taken on the 3rd, 5th, and 10th days, and if the patient was operated, additional samples were taken before the surgery and on the postoperative 1st, 5th, and 10th days. The relationship between trauma severity and serum IL-6 levels was analyzed statistically.

RESULTS

Mean serum IL-6 levels were 16.1, 46.4, 74.2 and 8.6 pg/mL respectively (group-1, -2A, -2B, and -3). There was a moderate correlation between MISS and IL-6 (p < 0.001). In group-2A, mean serum IL-6 levels were 13.9 pg/mL on the 3rd day and 9.1 on the 10th day. In group-2B they were 15.4 and 4.7 pg/mL, respectively. Also, for the patients undergoing surgically in group-2A, they were 36.0 pg/mL before the surgery, 33.2 on the 1st day, and 6.0 on the 10th day. For group-2B, they were 39.3, 37.4, and 7.9 pg/mL, respectively.

CONCLUSION

It was determined that serum IL-6 levels were significantly increased with increasing trauma severity. Systemic inflammation specified by IL-6 could decrease to almost normal on the 3rd day, and regress to normal on the following days. The concept of "second hit impact following surgical procedure" may also be kept in mind in children as in adults considering these alterations.

A short Mindfulness retreat can improve biological markers of stress and inflammation

OBJECTIVE

Mindfulness practice, a form of meditation, has shown benefit for psychological and physical health. In this study, we investigated the effect of an intensive period of Mindfulness practice on some biological mediators of stress and inflammation during a 3-day residential retreat.

METHODS

A total of 95 healthy individuals (aged 18-67) were recruited and randomized to a Mindfulness retreat arm or an active control arm. Before (t0) and after (t1) the intervention, all the participants were assessed for salivary cortisol levels and for a panel of pro- and anti-inflammatory cytokines measured in saliva. Psychometric measures on stress, anxiety and awareness were carried out using PSS, STAI-Y and MAAS questionnaires, respectively.

RESULTS

As to the within-group differences, we observed a statistically significant decrease in perceived stress (β = -8.85, p < 0.0001), and anxiety scores (β = -12.39, p < 0.0001), while awareness increased (β = 15.26, p < 0.0001) between t0 to t1 in retreat participants. In the mindfulness intervention group, we also observed a statistically significant reduction in the levels of pro-inflammatory cytokines IL-6 (β = -0.94 p = 0.001) and IL-8 (β = -176.40, p < 0.0001), and an increase in anti-inflammatory IL-10 (β = 0.89 p < 0.0001) levels at the end of the retreat. At t1 we observed a highly significant correlation between cortisol levels and both anxiety (r = 0.56, p < 0.0001) and perceived stress (r = 0.92, p < 0.0001) scores.

CONCLUSIONS

Mindfulness retreat participants showed a significant reduction in perceived stress and anxiety levels, as well as an improved balance of some key mediators of inflammatory states. Our data provide evidence that a mindfulness retreat may be effective in improving physical and mental health. Future studies with larger numbers of subjects and follow-up periods may examine mindfulness practice as a non-pharmacological alternative to promote stress reduction and overall health and wellbeing.

Cortisol and C-Reactive Protein Vary During Sleep Loss and Recovery but Are Not Markers of Neurobehavioral Resilience

Cortisol and C-reactive protein (CRP) typically change during total sleep deprivation (TSD) and psychological stress; however, it remains unknown whether these biological markers can differentiate robust individual differences in neurobehavioral performance and self-rated sleepiness resulting from these stressors. Additionally, little is known about cortisol and CRP recovery after TSD. In our study, 32 healthy adults (ages 27-53; mean ± SD, 35.1 ± 7.1 years; 14 females) participated in a highly controlled 5-day experiment in the Human Exploration Research Analog (HERA), a high-fidelity National Aeronautics and Space Administration (NASA) space analog isolation facility, consisting of two baseline nights, 39 h TSD, and two recovery nights. Psychological stress was induced by a modified Trier Social Stress Test (TSST) on the afternoon of TSD. Salivary cortisol and plasma CRP were obtained at six time points, before (pre-study), during [baseline, the morning of TSD (TSD AM), the afternoon of TSD (TSD PM), and recovery], and after (post-study) the experiment. A neurobehavioral test battery, including measures of behavioral attention and cognitive throughput, and a self-report measure of sleepiness, was administered 11 times. Resilient and vulnerable groups were defined by a median split on the average TSD performance or sleepiness score. Low and high pre-study cortisol and CRP were defined by a median split on respective values at pre-study. Cortisol and CRP both changed significantly across the study, with cortisol, but not CRP, increasing during TSD. During recovery, cortisol levels did not return to pre-TSD levels, whereas CRP levels did not differ from baseline. When sex was added as a between-subject factor, the time × sex interaction was significant for cortisol. Resilient and vulnerable groups did not differ in cortisol and CRP, and low and high pre-study cortisol/CRP groups did not differ on performance tasks or self-reported sleepiness. Thus, both cortisol and CRP reliably changed in a normal, healthy population as a result of sleep loss; however, cortisol and CRP were not markers of neurobehavioral resilience to TSD and stress in this study.

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.

What moderates salivary markers of inflammation reactivity to stress? A descriptive report and meta-regression

As the assessment of salivary markers of inflammation gains popularity in stress research, understanding factors that influence these markers' reactivity to stress is important. A recent meta-analysis synthesized literature on changes in salivary markers of inflammation in response to acute stressors in adults. As a supplement to this, we present pre-registered moderator analyses of salivary markers of inflammation responses to acute stress. Analyses included data from 27 studies (35 unique study samples). Outcomes were Cohen's d effect sizes for salivary biomarkers interleukin-1 beta (IL-1β), IL-6, IL-10, and tumor necrosis factor-alpha (TNF-α), from pre- to post-stress. Moderators included: college education levels of the study sample; percent of the study sample that identified as African-American; body mass index (BMI); use of a resting baseline saliva sample; and use of a social evaluative stressor. Descriptive results on saliva sample timing were also examined. Biomarkers peaked 0-60 minutes after the end of the stressor. Before removing influential outliers, no moderators of salivary inflammation reactivity emerged, though not all moderators could be tested due to missing data. After removing one influential outlier study, higher study sample average BMI was associated with greater salivary IL-1β reactivity to stress (b = 0.41, p=.007). For every 1-unit increase in study sample average BMI, effect sizes for IL-1β increased by 0.41 units. These findings suggest BMI may be important to examine when assessing salivary markers of inflammation in response to stress. As this field expands, it is important to replicate these results and consider the role of other moderators of salivary markers of inflammation reactivity to stress.

Alterations in Saliva and Plasma Cytokine Concentrations During Long-Duration Spaceflight

Long-duration spaceflight is known to cause immune dysregulation in astronauts. Biomarkers of immune system function are needed to determine both the need for and effectiveness of potential immune countermeasures for astronauts. Whereas plasma cytokine concentrations are a well-established biomarker of immune status, salivary cytokine concentrations are emerging as a sensitive indicator of stress and inflammation. For this study, to aid in characterizing immune dysregulation during spaceflight, plasma and saliva cytokines were monitored in astronauts before, during and after long-duration spaceflight onboard the International Space Station. Blood was collected from 13 astronauts at 3 timepoints before, 5 timepoints during and 3 timepoints after spaceflight. Saliva was collected from 6 astronauts at 2 timepoints before spaceflight, 2 timepoints during and 3 timepoints following spaceflight. Samples were analyzed using multiplex array technology. Significant increases in the plasma concentration of IL-3, IL-15, IL-12p40, IFN-α2, and IL-7 were observed during spaceflight compared to before flight baseline. Significant decreases in saliva GM-CSF, IL-12p70, IL-10 and IL-13 were also observed during spaceflight as compared to compared to before flight baseline concentrations. Additionally, plasma TGFβ1 and TGFβ2 concentrations tended to be consistently higher during spaceflight, although these did not reach statistical significance. Overall, the findings confirm an in-vivo hormonal dysregulation of immunity, appearing pro-inflammatory and Th1 in nature, persists during long-duration orbital spaceflight. These biomarkers may therefore have utility for monitoring the effectiveness of biomedical countermeasures for astronauts, with potential application in terrestrial research and medicine.

Response of salivary biomarkers to an empathy triggering film sequence-a pilot study

Empathy is a multifaceted phenomenon that is difficult to measure. Self-report questionnaires are the most common and well-validated measures while currently no validated protein biomarkers associated with the empathic reaction have been established. Trigger films have been previously used in psychological research to evoke emotions. Thus, in the present randomized cross-over study we investigated the responses of nine salivary biomarkers that have been related to emotions and stress following an empathy triggering and a control film sequence. Additionally, questionnaires for empathy (Saarbrucken Personality Questionnaire (SPQ)) and current mental stress were applied and participants were asked to assess the film protagonists’ emotions using the Positive and Negative Affect Schedule. Data from 46 participants were included in the analysis. α-Amylase, IgA, IL-1β and estradiol showed a significantly different response between the empathy and control intervention. Moreover, normalized levels of these biomarkers significantly correlated with single scales of the SPQ (control film sequence: α-amylase and IgA with personal distress; estradiol with empathic concern; IL-1β with fantasy; empathy triggering film sequence: IgA with empathic concern, fantasy and the total empathy score). These findings indicated that the observed changes in salivary biomarker levels were reflective of a physiological response to the empathy triggering film sequence. Future studies using different triggers and settings will show if the identified biomarkers can be considered as surrogate markers for empathic reactions in general.

Acceleration of Biological Aging and Underestimation of Subjective Age Are Risk Factors for Severe COVID-19

In an epidemic, it is important to have methods for reliable and rapid assessment of risk groups for severe forms of the disease for their priority vaccination and for the application of preventive lockdown measures. The aim of this study was to investigate risk factors for severe forms of COVID-19 in adults using indicators of biological and subjective aging. Longitudinal studies evaluated the severity of the disease and the number of cases. Respondents (447) were divided into "working group" and "risk group" (retirees with chronic diseases). During the lockdown period (in mid-2020), accelerated aging was observed in the group of workers (by 3.9-8 years for men and an increase at the tendency level for women). However, the respondents began to feel subjectively younger (by 3.3-7.2 years). In the risk group, there were no deviations from the expected biopsychological aging. The number of cases at the end of 2020 was 31% in workers and 0% in the risk group. Reasonably, the risk group followed the quarantine rules more strictly by 1.5 times. In working men, indicators of relative biological and relative subjective aging (measured in both 2019 and mid-2020) significantly influenced the incidence at the end of 2020. In women, only the indicators obtained in mid-2020 had a significant impact. The relative biological aging of an individual tested in the middle of 2020 had a direct impact on the risk of infection (p < 0.05) and on the probability of death (p < 0.0001). On the contrary, an increase in the relative subjective (psychological) aging index reduced the risk of infection (at the tendency level, p = 0.06) and the risk of death (p < 0.0001). Both the risk of infection and the risk of death increased with calendar age at the tendency level. Conclusions: Indicators of individual relative biological and subjective aging affect the probability of getting COVID-19 and its severity. The combination of high indicators of biological aging and underestimated indicators of subjective aging is associated with increased chances of developing severe forms of the disease.

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.

Inflammatory markers in acne vulgaris: Saliva as a novel diagnostic fluid

BACKGROUND

Despite the wide use of saliva-based measurements in inflammatory, autoimmune and neoplastic conditions, its use in dermatology is still limited.

AIMS

The aims of this study were to assess the serum and salivary levels of interleukin-1 beta (IL-1β) and C-reactive protein (CRP) in patients with acne vulgaris.

PATIENTS/METHODS

The study included 84 moderate-to-severe acne vulgaris patients, in addition to 105 healthy control subjects. Serum and salivary levels of CRP and IL-1β were estimated using enzyme-linked immunosorbent assay (ELISA) technique.

RESULTS

Using T-test, the serum and salivary levels of both CRP and IL-1β in the patients were significantly higher than the measured levels in the control subjects (p < 0.001). Using Pearson correlation coefficient, serum and salivary CRP and serum IL-1β levels showed significantly positive correlation with GAGS scores (p < 0.001). The levels of IL-1β in saliva did not show significant correlation with GAGS scores or with serum and salivary CRP.

CONCLUSIONS

The current study supports the emerging role of saliva as a valid noninvasive tool for monitoring inflammation and as a reliable and stress-free tool to evaluate cytokines and other inflammatory marker levels in acne vulgaris.

Association between metabolic and hormonal profile, proinflammatory cytokines in saliva and gingival health in adolescent females with polycystic ovary syndrome

Background

Research studies indicate that polycystic ovary syndrome (PCOS) may increase susceptibility to periodontal disease. The mechanisms that link both conditions are not entirely understood. Thus, the study aimed to investigate the impact of hormonal and metabolic disturbances on the gingival health and salivary levels of tumor necrosis factor (TNF-α), interleukin 1β (IL1-β), and interleukin 6 (IL-6) in adolescent girls with PCOS.

Methods

Thirty-one patients with PCOS and twenty-eight healthy age-mates (as the control group) were enrolled in the study. Individuals with PCOS underwent blood tests for the determination of hormonal and metabolic parameters. Saliva samples were collected to measure salivary testosterone and proinflammatory cytokines in both studied groups. Calibrated dentist assessed oral hygiene and gingival health of all subjects.

Results

Salivary testosterone was significantly higher in the study group (p = 0.0007). The groups did not differ significantly concerning periodontal parameters. Patients with PCOS revealed higher levels of salivary cytokines (p < 0.0001). Gingival index (GI) and the percentage of sites bleeding upon probing (BOP%) were positively correlated with the plaque index (PI) in both groups (r_s ≥ 0.60, p < 0.001), and negatively correlated with salivary testosterone level in the PCOS group (r_s = − 0.44, p = 0.0138 and r_s = − 0.37, p = 0.0424, respectively). BOP% was also positively correlated with body mass index (BMI) in the control group (r_s = 0.40, p = 0.0368) and index of insulin resistance (HOMA-IR) in the study group (r_s = 0.48, p = 0.0068). Salivary testosterone was positively correlated with TNF-α in the control group (r_s = 0.41, p = 0.0321), while in the study group, total testosterone (TT) was positively correlated with IL-6 (r_s = 0.37, p = 0.0400) and free androgen index (FAI) with TNF-α (r_s = 0.36, p = 0.0491).

Conclusions

Gingival health of the examined population was associated primarily with oral hygiene and, to a lesser extent, with the hormonal and metabolic profile. Despite similar periodontal parameters in the both studied groups, patients with PCOS revealed significantly higher levels of proinflammatory cytokines in saliva, which might be the manifestation of the systemic low-grade inflammation associated with PCOS.

Immune Responses after Heavy Alcohol Consumption: Cytokine Concentrations in Hangover-Sensitive and Hangover-Resistant Drinkers

This study investigated immunological changes during an alcohol hangover, and the possible difference between hangover-resistant and hangover-sensitive drinkers in terms of immune reactivity. Using a semi-naturalistic design, N = 36 healthy social drinkers (18 to 30 years old) provided saliva samples on a control day (after drinking no alcohol) and on a post-alcohol day. Hangover severity was rated directly after saliva collection. Cytokine concentrations, interleukin (IL)-1β, IL-6, IL-8, IL-10 and tumor necrosis factor (TNF)-α, and hangover severity were compared between both test days and between hangover-sensitive and -resistant drinkers. Data from N = 35 drinkers (17 hangover-sensitive and 18 hangover-resistant) were included in the statistical analyses. Relative to the control day, there were significant increases in saliva IL-6 and IL-10 concentrations on the post-alcohol day. No significant differences in cytokine concentrations were found between hangover-sensitive and hangover-resistant drinkers, nor did any change in cytokine concentration correlate significantly with hangover severity. In line with previous controlled studies assessing cytokines in blood, the current naturalistic study using saliva samples also demonstrated that the immune system responds to high-level alcohol intake. However, further research is warranted, as, in contrast to previous findings in blood samples, changes in saliva cytokine concentrations did not differ significantly between hangover-sensitive and hangover-resistant drinkers, nor did they correlate significantly with hangover severity.

Activation of the cholinergic antiinflammatory reflex by occipitoatlantal decompression and transcutaneous auricular vagus nerve stimulation

CONTEXT

The parasympathetic-mediated inflammatory reflex inhibits excessive proinflammatory cytokine production. Noninvasive techniques, including occipitoatlantal decompression (OA-D) and transcutaneous auricular vagus nerve stimulation (taVNS), have been demonstrated to increase parasympathetic tone.

OBJECTIVES

To test the hypothesis that OA-D and taVNS increase parasympathetic nervous system activity and inhibit proinflammatory cytokine mobilization and/or production.

METHODS

Healthy adult participants were randomized to receive OA-D (5 min of OA-D followed by 10 min of rest; n=8), taVNS (15 min; n=9), or no intervention (15 min, time control; n=10) on three consecutive days. Before and after these interventions, saliva samples were collected for determination of the cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor α (TNF-α). Arterial blood pressure and the electrocardiogram were recorded for a 30-min baseline, throughout the intervention, and during a 30-min recovery period to derive heart rate and blood pressure variability markers as indices of vagal and sympathetic control.

RESULTS

OA-D and taVNS increased root mean square of successive RR interval differences (RMSSD) and high frequency heart rate variability, which are established markers for parasympathetic modulation of cardiac function. In all three groups, the experimental protocol was associated with a significant increase in salivary cytokine concentrations. However, the increase in IL-1β was significantly less in the taVNS group (+66 ± 13 pg/mL; p<0.05) than in the time control group (+142 ± 24 pg/mL). A similar trend was observed in the taVNS group for TNF-α (+1.7 ± 0.3 pg/mL vs. 4.1 ± 1.3 pg/mL; p<0.10). In the OA-D group baseline IL-6, IL-8, and TNF-α levels on the third study day were significantly lower than on the first study day (IL-6: 2.3 ± 0.4 vs. 3.2 ± 0.6 pg/mL, p<0.05; IL-8: 190 ± 61 vs. 483 ± 125 pg/mL, p <0.05; TNF-α: 1.2 ± 0.3 vs. 2.3 ± 0.4 pg/mL, p<0.05). OA-D decreased mean blood pressure from the first (100 ± 8 mmHg) to the second (92 ± 6 mmHg; p<0.05) and third (93 ± 8 mmHg; p<0.05) study days and reduced low frequency spectral power of systolic blood pressure variability (19 ± 3 mmHg² after OA-D vs. 28 ± 5 mmHg² before OA-D; p<0.05), a marker of sympathetic modulation of vascular tone. OA-D also increased baroreceptor-heart rate reflex sensitivity from the first (13.7 ± 3.0 ms/mmHg) to the second (18.4 ± 4.3 ms/mmHg; p<0.05) and third (16.9 ± 4.2 ms/mmHg; p<0.05) study days.

CONCLUSIONS

Both OA-D and taVNS elicited antiinflammatory responses that were associated with increases in heart rate variability-derived markers for parasympathetic function. These findings suggest that OA-D and taVNS activate the parasympathetic antiinflammatory reflex. Furthermore, an antihypertensive effect was observed with OA-D that may be mediated by reduced sympathetic modulation of vascular tone and/or increased baroreceptor reflex sensitivity.

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.

Possible utilization of salivary IFN-γ/IL-4 ratio as a marker of chronic stress in healthy individuals

Introduction

Several studies show that psychological stress reduces Th1/Th2 ratio in blood samples. However, evidence is scarce regarding the cytokine alterations during stress in saliva. We investigated the influence of chronic stress on Th1/Th2 ratio and cytokine profiles in the saliva of healthy individuals. Further, we examined the associations of the salivary cytokine levels with sleep and attention problems, which are closely related with psychological stress.

Methods

Salivary levels of 27 cytokines were measured by multiplex bead array assays in 31 healthy young individuals (health science students and hospital staff consisting of 11 men and 20 women, mean age [standard deviation] =21.5 [0.8] years). The Kessler Psychological Distress scale (K10) and Athens Insomnia Scale (AIS) were administered to assess subjective chronic psychological stress and sleep problems. Further, participants were asked to wear Actigraph GT3X accelerometers for 3 days to assess the total sleep time. Attention problems were assessed by administering the Integrated Visual and Auditory Continuous Performance Test (IVA‐CPT).

Results

Thirteen cytokines with >80% detectable results were included in the main analyses. The IFN‐γ/IL‐4 ratio, which is a commonly used index for Th1/Th2 ratio, showed significant negative correlations with the K10 and AIS scores. None of the cytokines were significantly associated with sex, body mass index, sleep index measured by Actigraph, or IVA‐CPT scores.

Conclusion

Chronic stress may be associated with alterations of the Th1/Th2 balance in salivary cytokine production. IFN‐γ/IL‐4 ratio in saliva may serve as a potential biomarker of chronic stress in healthy individuals.

The present study investigated the influence of chronic stress on Th1/Th2 ratio and cytokine profiles in the saliva of healthy individuals. The IFN‐γ/IL‐4 ratio showed a significant negative correlation with chronic stress, assessed by the Kessler Psychological Distress scale. IFN‐γ/IL‐4 ratio in saliva may serve as a potential biomarker of chronic stress in healthy individuals.

Inflamed Mind: Multiple Genetic Variants of IL6 Influence Suicide Risk Phenotypes in Interaction With Early and Recent Adversities in a Linkage Disequilibrium-Based Clumping Analysis

Background: Understanding and predicting suicide remains a challenge, and a recent paradigm shift regarding the complex relationship between the immune system and the brain brought attention to the involvement of inflammation in neuropsychiatric conditions including suicide. Among cytokines, IL-6 has been most frequently implicated in suicide, yet only a few candidate gene studies and without considering the effect of stress investigated the role of IL6 in suicidal behaviour. Our study aimed to investigate the association of IL6 variation with a linkage disequilibrium-based clumping method in interaction with childhood adversities and recent stress on manifestations along the suicide spectrum. Methods: One thousand seven hundred and sixty-two participants provided information on previous suicide attempts, current suicidal ideation, thoughts of death, and hopelessness, and were genotyped for 186 variants in IL6. Early childhood adversities were recorded with an instrument adapted from the Childhood Trauma Questionnaire, recent life events were registered using the List of Threatening Life Events. Following a 3-step quality control, logistic and linear regression models were run to explore the effect of genotype and gene-environment interactions on suicide phenotypes. All regression models were followed by a clumping process based on empirical estimates of linkage disequilibrium between clumps of intercorrelated SNPs. Interaction effects of distinct types of recent life events were also analysed. Results: No clumps with significant main effects emerged, but we identified several clumps significantly interacting with childhood adversities on lifetime suicide attempts, current suicidal ideation, and current thoughts of death. We also identified clumps significantly interacting with recent negative life events on current suicidal ideation. We reported no clumps with significant effect on hopelessness either as a main effect or in interaction with childhood adversities or recent stress. Conclusion: We identified variant clumps in IL6 influencing suicidal behaviour, but only in interaction with childhood or recent adversities. Our results may bring us a step further in understanding the role of neuroinflammation and specifically of IL-6 in suicide, towards identifying novel biological markers of suicidal behaviour especially in those exposed to stressful experiences, and to fostering the adaptation of a new paradigm and identifying novel approaches and targets in the treatment of suicidal behaviour.

Examination of Oral Squamous Cell Carcinoma and Precancerous Lesions Using Proximity Extension Assay and Salivary RNA Quantification

Saliva is an easy-to access body fluid with high diagnostic potential. The utilization of saliva for oral cancer diagnosis can be an attractive possibility. Besides the oral cancer, it is important to better understand the precancerous lesions such as oral lichen planus (OLP) and leukoplakia (OLK). In order to examine the changes of salivary proteins in controls, patients with oral cancer, and patients with precancerous conditions, proximity extension assay was utilized. Some proteins and functions were characteristic to the examined groups and can serve as a starting point for further biomarker studies. The different nature of OLK and OLP was demonstrated, showing the malignant transformation and the inflammation as the prominent biological processes in the OLK and OLP, respectively. The salivary level of IL6 was verified using quantitative ELISA and the mRNA level was also studied. Elevated IL6 levels could be detected in precancerous groups compared to controls.

Interleukin dynamics during cognitive stress in patients with chronic cerebral ischemia

Neuroimmune interactions represent a highly dynamic mechanism for the regulation of cognitive function in chronic cerebral ischemia (CCI). The aim of this study was to investigate changes in salivary proinflammatory cytokines IL1β and IL6 and anti-inflammatory IL10 in patients with CCI (mean age 65.4 ± 9.1 years) before and after cognitive tests. After cognitive tests, the levels of salivary IL1β and IL6 were significantly elevated by 101.6 ± 19.1 pg/ml (n = 74) and 32.8 ± 6.1 pg/ml (n = 74), respectively. Using one-way ANOVA ana non-parametric statistical methods, we were able to demonstrate associations between changes in salivary interleukins and cognitive performance. In the group of patients with a significant increase in IL1β, some cognitive parameters were lower than in the group with negative or zero dynamics of this cytokine: the patients made more mistakes in the subtraction test (F = 11.5; n = 63; p = 0.001) and performed worse in the Luria test (F = 6.8; n = 65; p = 0.01). For IL6, Spearman’s rank correlation coefficient for the number of mistakes in the subtraction test was positive and differed significantly from 0 (R = 0.26; n = 62; p = 0.042). The group with positive IL10 dynamics performed better in N-back test (F = 5.2; n = 67; p = 0.03) and made fewer mistakes in the subtraction test (F = 6.8; n = 63; p = 0.01) in comparison with patients who demonstrated negative IL10 dynamics. Good performance in other cognitive tests was not correlated with interleukin dynamics. The article also discusses possible mechanisms underlying interleukin effects on cognitive function in patients with CCI and applications of the obtained data.

Levels of Interleukin-6 in Saliva, but Not Plasma, Correlate with Clinical Metrics in Huntington's Disease Patients and Healthy Control Subjects

Growing evidence suggests that inflammatory responses, in both the brain and peripheral tissues, contribute to disease pathology in Huntington's disease (HD), an inherited, progressive neurodegenerative disorder typically affecting adults in their 30-40 s. Hence, studies of inflammation-related markers in peripheral fluids might be useful to better characterize disease features. In this study, we measured levels of C-reactive protein (CRP), Interleukin-6 (IL-6), interleukin 1 beta (IL-1B), and alpha-amylase (AA) in saliva and plasma from n = 125 subjects, including n = 37 manifest HD patients, n = 36 premanifest patients, and n = 52 healthy controls, using immunoassays. We found increases in salivary levels of IL-6, IL-1B and CRP across different disease groups and increased levels of IL-6 in the plasma of HD patients as compared to premanifest patients and controls. The levels of salivary IL-6 were significantly correlated with each of the other salivary markers, as well as with IL-6 levels measured in plasma. Further, salivary IL-6 and IL-1B levels were significantly positively correlated with Total Motor Score (TMS) and chorea scores and negatively correlated with Total Functional Capacity (TFC) in HD patients, whereby in healthy control subjects, IL-6 was significantly negatively correlated with Montreal Cognitive Assessment (MoCA) and the Symbol Digit Modalities test (SDM). Interestingly, the plasma levels of IL-6 did not show similar correlations to any clinical measures in either HD or control subjects. These findings suggest that salivary IL-6 is particularly relevant as a potential non-invasive biomarker for HD symptoms. The advent of an effective, dependable salivary biomarker would meet the urgent need for a less invasive means of identifying and monitoring HD disease progression.

Effects of Intermittent Fasting and Physical Activity on Salivary Expression of Reduced Glutathione and Interleukin-1β

Previous research has consistently demonstrated that regular exercise promotes antioxidant production and decreases the expression of inflammation markers. However, there is very little research examining the effects of intermittent fasting (IF) on oxidative stress and inflammation. The present study investigated the hypothesis that a combination of IF and physical activity will reduce the need for glutathione (GSH) production by decreasing oxidative stress. In addition, it was hypothesized that a combination of IF and physical activity will significantly reduce inflammation, as indicated by a decrease in interleukin-1β (IL-1β) concentration. For three months, subjects practicing IF (n=7) ate only during an eight-hour window each day and fasted for the next 16 hours. A standard diet control group (n=18) maintained a normal, balanced diet spread out over the course of 14-18 hours each day. Based on data obtained from fitness-tracking devices, subjects were placed into one of three activity level groups: minimum, moderate, and maximum physical activity. Subjects provided fasting saliva samples monthly. The samples were subjected to a glutathione microplate assay and an interleukin ELISA test to determine salivary concentrations of GSH and IL-1β, respectively. For GSH concentration, there were no significant differences between the diets at any physical activity level. However, moderate to maximum physical activity, in conjunction with fasting, led to significant decreases in IL-1β concentration. In summary, results suggest that a combination of moderate physical activity and intermittent fasting promotes the maintenance of antioxidant function while inhibiting the inflammatory process.

The effect of acute stress on salivary markers of inflammation: A systematic review and meta-analysis

BACKGROUND

Salivary biomarkers of inflammation are increasingly used in stress research. This systematic review and meta-analysis provides a quantitative summary of changes in salivary inflammatory markers in response to acute stress.

METHOD

The review included 1558 participants (42 unique samples, 33 studies) obtained through electronic databases (PubMed, PsycINFO, Embase), reference treeing, and articles identified by a 2015 review on a similar topic. To be eligible, articles had to be quantitative and assess change in at least one biomarker of salivary inflammation in response to acute stress in adults. The primary outcome was magnitude of change in inflammatory biomarkers (Cohen's d for repeated measures [dav]).

RESULTS

Measures of salivary inflammation included: C-reactive protein (CRP), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, IL-13, IL-17A, IL-18, IL-21, interferon (IFN)-α, IFN-γ, and tumor necrosis factor (TNF)-α. Cytokines IL-6 (k = 26, dav = 0.27), IL-10 (k = 11, dav = 0.34), TNF-α (k = 10, dav = 0.57), and IFN-γ (k = 6, dav = 0.28) significantly increased in response to stress. Post hoc sensitivity analyses revealed that IL-1β (k = 19, dav = 0.16) and IL-8 (k = 7, dav = 0.30) also increased from pre- to post-stress, but findings with IFN-γ did not hold after removing one outlier study. Examination of moderators suggested that study methodology and sample demographics moderated some associations.

CONCLUSIONS

This meta-analysis revealed that certain salivary inflammatory cytokines increase in response to acute stress. Significant heterogeneity in results and moderator analyses suggest need for standardization of research protocols. Directions for future research are discussed.