Salivary alpha-amylase as a non-invasive biomarker for the sympathetic nervous system: current state of research

Unveiling stress markers: A systematic review investigating psychological stress biomarkers

Psychological stress is a ubiquitous facet of modern life, impacting individuals across diverse contexts and demographics. Understanding its physiological manifestations through biomarkers has gained substantial attention within the scientific community. A comprehensive search was conducted across multiple databases for peer-reviewed articles published within the past decade. Preliminary findings reveal many biomarkers associated with psychological stress across different biological systems, including the hypothalamic-pituitary-adrenal axis, immune system, cardiovascular system, and central nervous system. This systematic review explores psychological, physiological, and biochemical biomarkers associated with stress. Analyzing recent literature, it synthesizes findings across these three categories, elucidating their respective roles in stress response mechanisms. Psychological markers involve subjective assessments like self-reported stress levels, perceived stress scales, or psychometric evaluations measuring anxiety, depression, or coping mechanisms. Physiological markers include heart rate variability, blood pressure, and immune system responses such as cytokine levels or inflammatory markers. Biochemical markers involve hormones or chemicals linked to stress. It includes cortisol, catecholamines, copeptin, salivary amylase, IL-6, and C-reactive protein.

Radiation-associated changes in saliva composition of head and neck cancer patients: A systematic review

Xerostomia is a common radiation-associated toxicity in patients with head and neck cancer. Although several studies examined the decrease in saliva production due to radiotherapy (RT) and investigated the factors associated with this side effect, little is known about the change in radiation-associated saliva composition. This systematic review is the first to summarize existing data and give an overview of the change in pH/buffer capacity, electrolytes, proteins, enzymes, and mucins due to radiation to the salivary glands. Literature search was performed in PubMed and Embase with 47 articles finally eligible for the review, analyzing the saliva composition at several time points before, during and/or after RT, or comparing findings in irradiated patients to a healthy control group. Overall, RT leads to a substantial decrease in salivary pH and buffer capacity. For sodium, chloride and calcium ion, as well as amylase, an increased concentration or activity during RT was reported in most of the studies, followed by a subsequent decrease either already during RT or after the end of treatment. Different trends have been described for the total protein concentration during and after RT. Lactoferrin, however, increased considerably, especially in the first phase of RT. Mucin 5B (MUC5B) concentrations showed a slight increase during RT and concentrations around baseline values again six months post-radiotherapy.

Timing matters: A meta-analysis on the dynamic effect of stress on salivary immunoglobulin

The impact of psychological stress on physiological systems has been a focus of extensive research, particularly in understanding its diverse effects on immune system activity and disease risk. This meta-analysis explores the dynamic effect of acute stress on salivary immunoglobulin-A (S-IgA) levels, a key biomarker for secretory immunity within the oral environment. Analyzing data from 34 samples comprising 87 effect sizes and a total of 1,025 subjects, a multi-level approach is employed to account for the temporal variability in measuring the stress response. The results reveal a significant increase in S-IgA levels peaking around 10 min after stress exposure, followed by a return to baseline levels approximately 30 min later. In addition, the meta-analysis identified several research gaps of the extant literature, such as limitations in the considered time lag after stress. In conclusion, the findings emphasize the temporal nuances of the S-IgA response to stress, which can help to infer potential biological pathways and guide sampling designs in future studies. Further, we highlight the use of a multi-level meta-analysis approach to investigate the temporal dependencies of the interplay between stress and immune functioning.

Stress biomarkers and child development in young children in Bangladesh

BACKGROUND

Hundreds of millions of children in low- and middle-income countries are exposed to chronic stressors, such as poverty, poor sanitation and hygiene, and sub-optimal nutrition. These stressors can have physiological consequences for children and may ultimately have detrimental effects on child development. This study explores associations between biological measures of chronic stress in early life and developmental outcomes in a large cohort of young children living in rural Bangladesh.

METHODS

We assessed physiologic measures of stress in the first two years of life using measures of the hypothalamic-pituitary-adrenal (HPA) axis (salivary cortisol and glucocorticoid receptor gene methylation), the sympathetic-adrenal-medullary (SAM) system (salivary alpha-amylase, heart rate, and blood pressure), and oxidative status (F2-isoprostanes). We assessed child development in the first two years of life with the MacArthur-Bates Communicative Development Inventories (CDI), the WHO gross motor milestones, and the Extended Ages and Stages Questionnaire (EASQ). We compared development outcomes of children at the 75th and 25th percentiles of stress biomarker distributions while adjusting for potential confounders using generalized additive models, which are statistical models where the outcome is predicted by a potentially non-linear function of predictor variables.

RESULTS

We analyzed data from 684 children (49% female) at both 14 and 28 months of age; we included an additional 765 children at 28 months of age. We detected a significant relationship between HPA axis activity and child development, where increased HPA axis activity was associated with poor development outcomes. Specifically, we found that cortisol reactivity (coefficient -0.15, 95% CI (-0.29, -0.01)) and post-stressor levels (coefficient -0.12, 95% CI (-0.24, -0.01)) were associated with CDI comprehension score, post-stressor cortisol was associated with combined EASQ score (coefficient -0.22, 95% CI (-0.41, -0.04), and overall glucocorticoid receptor methylation was associated with CDI expression score (coefficient -0.09, 95% CI (-0.17, -0.01)). We did not detect a significant relationship between SAM activity or oxidative status and child development.

CONCLUSIONS

Our observations reveal associations between the physiological evidence of stress in the HPA axis with developmental status in early childhood. These findings add to the existing evidence exploring the developmental consequences of early life stress.

Trauma film viewing and intrusive memories: Relationship between salivary alpha amylase, endocannabinoids, and cortisol

The endogenous cannabinoid (ECB) system is a small molecule lipid signalling system that is involved in stress response activation and is associated with PTSD, but it is unclear whether salivary ECBs are part of the sympathetic nervous system response to stress. We conducted an adapted trauma film paradigm, where participants completed a cold pressor test (or control) while watching a 10-minute trauma film. We also collected saliva and hair samples and tested them for ECBs, cortisol, and salivary alpha amylase (sAA). As hypothesised, there were significant positive correlations between sAA activity and salivary ECB levels, particularly 2-arachidonoyl glycerol (2-AG), though ECBs were not correlated with sAA stress reactivity. Participants who had a significant cortisol response to the trauma film/stressor reported less intrusive memories, which were also less distressing and less vivid. This effect was moderated by arachidonoyl ethanolamide (AEA), where decreases in AEA post-stress were associated with more intrusive memories in cortisol non-responders only. This study provides new evidence for the role of ECBs in the sympathetic nervous system.

From Social Stress and Isolation to Autonomic Nervous System Dysregulation in Suicidal Behavior

PURPOSE OF REVIEW

In this narrative review we wanted to describe the relationship of autonomic nervous system activity with social environment and suicidal spectrum behaviors.

RECENT FINDINGS

Patients with suicidal ideation/suicide attempt have higher sympathetic nervous system (SNS) and lower parasympathetic nervous system (PNS) activity in resting conditions and during acute stress tasks compared with patients without suicidal ideation/suicide attempt. Death by suicide and violent suicide attempt also are related to SNS hyperactivation. Similarly, a SNS/PNS imbalance has been observed in people with childhood trauma, stressful life events or feelings of loneliness and isolation. Social support seems to increase PNS control and resilience. Due to the importance of the social context and stressful life events in suicidal behavior, SNS/PNS imbalance could act as a mediator in this relationship and be a source of relevant biomarkers. Childhood trauma and stressful life events may impair the autonomic nervous system response in suicidal patients. Loneliness, isolation and social support may act as moderators in acute stress situations.

An acute social stressor decreases reinforcing value of both high and low energy-dense food in college students in a randomized controlled trial

It is well known that a large portion of the population elevates their intake of high energy-dense foods during times of stress; however, it is understudied whether stress affects the reinforcing value of a food reward. Further knowledge of this relationship may help us better understand the positive correlation between reinforcing value of food and obesity. Therefore, it was tested if an acute stressor would increase the reinforcing value of low or high energy-dense food. Participants (N = 70) were randomized to a stress or no-stress condition after which they were allowed to work to gain access to a food reward and reading time. To determine if high energy-dense food was specifically affected, half the participants from each stress manipulation were randomly assigned to work for either grapes or chocolate candies. Participants in the stress condition worked less for food access than those in the no-stress condition, for both low and high energy-dense foods, but stress did not affect the reinforcing value of reading time. These results indicate that, contrary to our hypothesis, in a sample of college students, an acute stressor decreased reinforcing value of food, with no difference between a low and high energy-dense food item.

Evaluation of salivary stress markers and inflammatory cytokine levels in peri-implantitis patients

BACKGROUND AND OBJECTIVE

Psychological stress has been identified in some observational studies as a potential factor that may modify and affect periodontal diseases, but there are no similar data for peri-implantitis. The aim of this study was to determine the relationship between interleukin (IL)-1β, IL-6, IL-10, interferon (IFN)α inflammatory cytokines and the psychological stress-related markers, glucocorticoid receptor-α (GRα), and salivary α-amylase (sAA) gene expression levels in saliva samples obtained from healthy implants and peri-implantitis patients.

MATERIALS AND METHODS

The study included a total of 50 systemically healthy subjects. Peri-implant clinical parameters were recorded and psychological stress level was evaluated with the hospital anxiety and depression scale (HAD) and state-trait anxiety inventory (STAI) questionnaire forms. Following the evaluations, the patients were divided into 4 groups according their stress and clinical status (Ia, Ib, IIa, IIb). IL-1β, IL-6, IL-10, IFNα, GRα, sAA gene expression levels in the saliva samples were quantified by quantitative polymerase chain reaction (qPCR).

RESULTS

In the group of peri-implantitis who had a high score in stress level assessment scales, significantly higher IL-1β, IL-6, sAA expression levels were observed (p < 0.001). The IL-10 gene expression levels were lower in the groups with a high score in the stress level assessment scales (p < 0.001). GRα gene was expressed at lower levels in the group of peri-implantitis who had a high score in stress level assessment scales but the difference was not statistically significant (p = 0.065).

CONCLUSION

The study findings suggest that psychological stress may increase the inflammation associated with peri-implantitis by affecting cytokine expression levels.

CLINICAL RELEVANCE

To prevent peri-implantitis or reduce its prevalence, it could be beneficial to evaluate stress levels and identify individuals experiencing stress.

A cluster-randomized trial of water, sanitation, handwashing and nutritional interventions on stress and epigenetic programming

A regulated stress response is essential for healthy child growth and development trajectories. We conducted a cluster-randomized trial in rural Bangladesh (funded by the Bill & Melinda Gates Foundation, ClinicalTrials.gov NCT01590095) to assess the effects of an integrated nutritional, water, sanitation, and handwashing intervention on child health. We previously reported on the primary outcomes of the trial, linear growth and caregiver-reported diarrhea. Here, we assessed additional prespecified outcomes: physiological stress response, oxidative stress, and DNA methylation (N = 759, ages 1-2 years). Eight neighboring pregnant women were grouped into a study cluster. Eight geographically adjacent clusters were block-randomized into the control or the combined nutrition, water, sanitation, and handwashing (N + WSH) intervention group (receiving nutritional counseling and lipid-based nutrient supplements, chlorinated drinking water, upgraded sanitation, and handwashing with soap). Participants and data collectors were not masked, but analyses were masked. There were 358 children (68 clusters) in the control group and 401 children (63 clusters) in the intervention group. We measured four F2-isoprostanes isomers (iPF(2α)-III; 2,3-dinor-iPF(2α)-III; iPF(2α)-VI; 8,12-iso-iPF(2α)-VI), salivary alpha-amylase and cortisol, and methylation of the glucocorticoid receptor (NR3C1) exon 1F promoter including the NGFI-A binding site. Compared with control, the N + WSH group had lower concentrations of F2-isoprostanes isomers (differences ranging from -0.16 to -0.19 log ng/mg of creatinine, P < 0.01), elevated post-stressor cortisol (0.24 log µg/dl; P < 0.01), higher cortisol residualized gain scores (0.06 µg/dl; P = 0.023), and decreased methylation of the NGFI-A binding site (-0.04; P = 0.037). The N + WSH intervention enhanced adaptive responses of the physiological stress system in early childhood.

Machine learning-based detection of acute psychosocial stress from body posture and movements

Investigating acute stress responses is crucial to understanding the underlying mechanisms of stress. Current stress assessment methods include self-reports that can be biased and biomarkers that are often based on complex laboratory procedures. A promising additional modality for stress assessment might be the observation of body movements, which are affected by negative emotions and threatening situations. In this paper, we investigated the relationship between acute psychosocial stress induction and body posture and movements. We collected motion data from N = 59 individuals over two studies (Pilot Study: N = 20, Main Study: N = 39) using inertial measurement unit (IMU)-based motion capture suits. In both studies, individuals underwent the Trier Social Stress Test (TSST) and a stress-free control condition (friendly-TSST; f-TSST) in randomized order. Our results show that acute stress induction leads to a reproducible freezing behavior, characterized by less overall motion as well as more and longer periods of no movement. Based on these data, we trained machine learning pipelines to detect acute stress solely from movement information, achieving an accuracy of75.0 ± 17.7 % (Pilot Study) and73.4 ± 7.7 % (Main Study). This, for the first time, suggests that body posture and movements can be used to detect whether individuals are exposed to acute psychosocial stress. While more studies are needed to further validate our approach, we are convinced that motion information can be a valuable extension to the existing biomarkers and can help to obtain a more holistic picture of the human stress response. Our work is the first to systematically explore the use of full-body body posture and movement to gain novel insights into the human stress response and its effects on the body and mind.

Evaluation of salivary α-amylase and immunoglobulin A responses after endurance exercise in adolescent males and females with similar aerobic fitness

The objective of this study was to clarify whether there are sex-specific differences in salivary α-amylase and immunoglobulin A responses following acute endurance exercise in adolescent males and females with equivalent cardiorespiratory fitness levels. Twenty-six aerobically trained adolescent males and females with similar training status were enrolled in this study. Each individual executed a 1-h prolonged cycling exercise corresponding to a constant power output at 65% of peak oxygen uptake. Unstimulated whole salivary samples were taken with the passive drooling method at the 10-min period before and after exercise for the determination of salivary responses [α-amylase, immunoglobulin A, total protein and flow rate]. Salivary α-amylase activity, immunoglobulin A concentration and total protein concentration were significantly augmented immediately after acute endurance exercise. Regarding sex differences, only the salivary flow rate was significantly lower in females than in males. The findings of the present study imply that adolescent males and females appear to have similar salivary responses after acute endurance exercise, as represented by salivary α-amylase activity and immunoglobulin A concentration in connection with total protein concentration and salivary flow rate, when they are matched for peak oxygen uptake relative to fat-free body mass.

Spectroscopic and in silico evaluation of hesperetin, aglycone flavanone, as a prospective regulatory ligand for human salivary α-amylase

The insight into the binding mechanism of hesperetin, an aglycone flavanone, with human salivary α-amylase (HSAA), simulated under physiological salivary condition, was explored using various spectroscopic approaches and in silico method. Hesperetin effectively quenched the intrinsic fluorescence of HSAA and the quenching was mixed quenching mechanism. The interaction perturbed the HSAA intrinsic fluorophore microenvironment and the enzyme global surface hydrophobicity. The negative values of ΔG for thermodynamic parameters and in silico study revealed the spontaneity of HSAA-hesperetin complex while the positive values of enthalpy change (ΔH) and entropy change (ΔS) showed noticeable involvement of hydrophobic bonding in the stabilization of the complex. Hesperetin was a mixed inhibitor for HSAA with a KI of 44.60 ± 1.63 μM and having apparent inhibition coefficient (α) of 0.26. Macromolecular crowding, given rise to microviscosity and anomalous diffusion, regulated the interaction. Sodium ion (Na+) created high ionic strength, also, modulated the interaction. The in silico study proposed the preferential binding of hesperetin at the active cleft domain of HSAA with the least energy of -8.0 kcal/mol. This work gives a novel insight on the potentials of hesperetin as a future prospective medicinal candidate in the management of postprandial hyperglycemic condition.Communicated by Ramaswamy H. Sarma.

Decreased salivary alpha-amylase reactivity for excluded young women after a speech task

Salivary alpha-amylase (sAA) has gained popularity as an easily collected biomarker for sympathetic nervous system activation, and research has shown increases in sAA after completing experimental stress tasks in certain groups. However, recent work suggests that salivary cortisol, another stress biomarker, is suppressed after a speech task among experimentally induced exclusion in young women. The present analysis investigated the sAA response in biologically female undergraduates (n=31) who completed a game of Cyberball and then a speech anticipation task. Results showed that women in the social exclusion experimental group had a greater decrease in sAA compared to young women in the inclusion group after the speech task. Results of this study provide support for stress response suppression in women who have experienced social exclusion. The present findings provide pilot evidence for future, larger studies to advance the tend-and-befriend theory.

Association among childhood adversity and susceptibility to interference during varying salience: two studies in healthy males

Childhood adversity, a prevalent experience, is related to a higher risk for externalizing and internalizing psychopathology. Alterations in the development of cognitive processes, for example in the attention-interference domain may link childhood adversity and psychopathology. Interfering stimuli can vary in their salience, i.e. ability to capture attentional focus, and valence. However, it is not known if interference by salience or valence is associated with self-reported adversity. In two independent study samples of healthy men (Study 1: n = 44; mean age [standard deviation (SD)] = 25.9 [3.4] years; Study 2: n = 37; 43.5 [9.7] years) we used the attention modulation task (AMT) that probed interference by two attention-modulating conditions, salience and valence separately across repeated target stimuli. The AMT measures the effects of visual distractors (pictures) on the performance of auditory discrimination tasks (target stimuli). We hypothesized that participants reporting higher levels of childhood adversity, measured with the childhood trauma questionnaire, would show sustained interference in trials with lower salience. Due to conflicting reports on the valence-modulation, we tested the valence condition in an exploratory manner. Linear mixed models revealed an interaction between reported childhood adversity and the salience condition across tone presentations in both study samples (Sample 1: p = .03; Sample 2: p = .04), while there were no effects for the valence condition across both studies. Our study suggests that higher self-reported childhood adversity is related to faster processing of target cues during high salience, but slower during low salience conditions. These results hint to the mechanisms linking childhood adversity and psychopathological symptoms in the attentional domain.

Stability and durability of salivary alpha-amylase across different storage conditions

Data collection in remote and field settings gains importance and popularity in stress research. Accordingly, existing stress induction paradigms have been successfully adapted to remote and field settings. However, guidelines for the comprehensive assessment of biomarkers such as salivary alpha-amylase (sAA) have yet to be sufficiently established for such contexts. In remote and field settings, swift freezing of saliva samples is not always possible, and samples must be returned to the laboratory for further processing. The current study investigated the robustness of sAA activity against external factors that may affect measurements obtained from saliva samples collected in field and remote settings. We compared sAA activity of samples that were stored in different vials (Salivettes® and Eppendorf® vials) and that were exposed to (1) up to three cycles of freezing and thawing, (2) different temperatures (4 °C, 20 °C, 30 °C, and 40 °C) for 3, 7, 14, or 28 days, or that were (3) sent via postal delivery. Results indicate sAA activity to be susceptible across different temperatures, different time intervals, and different vials. As a systematic pattern, sAA activity seems to decrease in treated samples with this effect being potentiated by more extreme conditions such as higher temperatures and longer time intervals. To conclude, sAA data collected in remote or field settings could be affected systematically by various external variables. Future studies collecting sAA should take factors influencing the durability and stability of sAA into account to ensure reliable and valid measurements of salivary data.

Genetic and environmental influences on alpha amylase stress reactivity and shared genetic covariation with cortisol

Salivary alpha amylase (sAA) is a common measure of stress reactivity, primarily reflecting sympathetic nervous system activity. Salivary cortisol is also a reliable, frequently used biomarker of stress and reflects the hypothalamic-pituitary-adrenal (HPA) axis response. This study examined heritability across varying metrics of sAA in response to a social evaluative stressor, the Trier Social Stress Test (TSST). The goal of this study was to estimate genetic and environmental influences on measurements of sAA stress reactivity. Moreover, we evaluated the shared genetic covariation between sAA and cortisol. Participants included twins aged 15-20 years (54% female). We measured alpha amylase and cortisol reactivity to the TSST via serial salivary cortisol samples collected pre- and post-TSST. Modest to moderate heritability estimates (11-64%) were observed across measures purported to capture alpha amylase stress reactivity (peak, area under the curve, baseline-to-peak change). Findings also indicate that sAA baseline and peak are primarily influenced by a shared genetic factor. There was no evidence of shared genetic influences between sAA and cortisol. These findings suggest the genetic control of the HPA and Sympathetic Adreno-Medullar axis are genetically independent of one another despite both playing a role in response to stressors.

Experimental apical periodontitis alters salivary biochemical composition and induces local redox state disturbances in the salivary glands of male rats

OBJECTIVES

The objective was to evaluate the effects of experimental apical periodontitis on the inflammatory, functional, biochemical, and redox parameters of the parotid and submandibular glands in rats.

MATERIALS AND METHODS

Twenty 12-week-old male Wistar rats were randomly divided into two groups (n = 10): a control group and apical periodontitis group. After 28 days, the saliva was collected for salivary flow rate and biochemistry composition. Both glands were sampled for quantification of the tumor necrosis factor-alpha (TNF-α) and biochemical analyses of redox state.

RESULTS

TNF-α concentrations were higher in both salivary glands adjacent to the periapical lesions in animals with apical periodontitis and also compared to the control group. The apical periodontitis group increased the salivary amylase, chloride, potassium, calcium, and phosphate. The total oxidant capacity increased in the parotid gland adjacent to the periapical lesions in the same rat and compared to the control group. Conversely, the total antioxidant capacity of the parotid glands on both sides in the apical periodontitis group was lower than that in the control group. Furthermore, glutathione peroxidase activity increased in the submandibular gland adjacent to the apical periodontitis group compared to the control group.

CONCLUSIONS

Experimental apical periodontitis alters salivary biochemical composition, in addition to increasing inflammatory marker and inducing local disturbances in the redox state in the parotid and submandibular glands of male rats.

CLINICAL RELEVANCE

Apical periodontitis could exacerbate the decline in oral health by triggering dysfunction in the salivary glands.

Biomarkers for assessing pain and pain relief in the neonatal intensive care unit

Newborns admitted to the neonatal intensive care unit (NICU) regularly undergo painful procedures and may face various painful conditions such as postoperative pain. Optimal management of pain in these vulnerable preterm and term born neonates is crucial to ensure their comfort and prevent negative consequences of neonatal pain. This entails accurate and timely identification of pain, non-pharmacological pain treatment and if needed administration of analgesic therapy, evaluation of treatment effectiveness, and monitoring of adverse effects. Despite the widely recognized importance of pain management, pain assessment in neonates has thus far proven to be a challenge. As self-report, the gold standard for pain assessment, is not possible in neonates, other methods are needed. Several observational pain scales have been developed, but these often rely on snapshot and largely subjective observations and may fail to capture pain in certain conditions. Incorporation of biomarkers alongside observational pain scores holds promise in enhancing pain assessment and, by extension, optimizing pain treatment and neonatal outcomes. This review explores the possibilities of integrating biomarkers in pain assessment in the NICU.

Multifactorial stress reactivity to virtual TSST-C in healthy children and adolescents-It works, but not as well as a real TSST-C

A virtual version of the Trier Social Stress Test (TSST) has been increasingly used in stress research. Benefits of the virtual TSST include that it is more economical, and offers improved control of context and enhanced flexibility of use. Many studies have confirmed the applicability of virtual TSSTs in stress research, but only in adulthood. In the present study, we aimed to experimentally verify the transferability of a virtual TSST to adolescence. A total of 73 healthy adolescents (aged 11-17 years) of both sexes completed either a real (IV-TSST-C) or virtual (VR-TSST-C) TSST for children. The surveyed stress parameters included salivary cortisol and alpha amylase concentrations, heart rate, heart rate variability, and subjective stress ratings across test sessions, as well as a pre- to post-TSST-C comparison. All parameters revealed significant stress responses over time. We observed significant effects of group on cortisol and subjective stress ratings, with the VR-TSST-C inducing less stress than the IV-TSST-C. In alpha amylase, heart rate, and heart rate variability, we found no significant difference between TSST versions, but only significant equivalence for alpha amylase. Some parameters may have been influenced by an expectancy effect and the participant's sex. In conclusion, among adolescents, a virtual TSST-C effectively elicits stress at multiple levels (endocrinological, autonomic, and subjective); however, the magnitude is not always comparable to with the real TSST-C, which should be considered when applied.

Influence of controlled environmental conditions in potential salivary ocular pain biomarkers for enhancing the assessment of ocular pain

PURPOSE

We endeavored to identify objective salivary biomarkers for pain, a subjective sensation with a biological basis, using molecules already described related to pain. The study aimed to analyze inter-individual differences and intersession variability in salivary potential ocular pain biomarkers on healthy subjects, in samples obtained under the influence of controlled environmental conditions.

METHODS

Thirty-four healthy subjects, 20 male, 14 female, median age 35.44 years (range 30-40) were exposed for 30 minutes under standard environmental conditions (T: 22°C, 50% relative humidity) in the Controlled Environmental Research Laboratory (CE-Lab, Vision R&D, Valladolid Spain) in two separate visits (V1, V2) at least 24 hours apart. Saliva was collected after the exposure in each of the visits, and cortisol, α-amylase (sAA), secretory IgA (sIgA), testosterone, and soluble fraction of TNFα receptor II (sTNFαRII) were analyzed by ELISA. Repeatability of inter-subject inter-session measurements was assayed by intraclass correlation coefficient (ICC).

RESULTS

There were no significant inter-session differences in testosterone (p = 0.2497), sTNFαRII (p = 0.6451) and sIgA (p = 0.9689) salivary levels. The reproducibility for salivary cortisol, sAA, testosterone, sTNFαRII and sIgA were 0.98 ng/ml, 20.58 U/ml, 21.07 μg/ml, 24.68 pg/ml and 0.19 pg/ml, respectively. Salivary cortisol, sAA, testosterone, sTNFαRII and sIgA yielded the following ICCs: 0.506, 0.569, 0.824, 0.870 and 0.4295, respectively; all these ICCs (except that for cortisol and sIgA) were found to be improved compared to those found previously by our group in a previous study in salivary samples obtained from healthy subjects under non-controlled environmental conditions; Cortisol´s ICC didn´t improve and was in both cases at the limit of acceptability.

CONCLUSION

Environmental factors such as temperature and relative humidity affect the reproducibility of measurement of some salivary molecules which have been proposed as potential pain biomarkers. The exposure of subjects to standard controlled environmental conditions before salivary sample obtention would improve the reproducibility of these molecule measures' as potential biomarkers of chronic ocular pain.

Trends in waking salivary alpha-amylase levels following healing lucid dreams

Introduction

Salivary alpha-amylase (sAA) is considered a marker of autonomic nervous system activity in stress research, and atypical waking sAA responses have been reported for traumatized individuals. Lucid dreams, characterized by a dreamer's awareness of their dream state while remaining asleep, have shown promising preliminary evidence of their potential to enhance mental health. This study's objective was to evaluate sAA in relation to healing lucid dreams.

Methods

Participants experiencing PTSD symptoms attended a six-day workshop delivered via live video designed to teach techniques for transforming trauma through dreamwork and dream lucidity. Participants (n = 20) collected saliva samples each morning, immediately upon awakening (Time 1) and 30 min afterward (Time 2). sAA levels were determined by enzymatic assay, and the waking sAA slope was calculated as the difference of Time 2 minus Time 1. Participants completed dream reports each morning, with a dream classified as a 'healing lucid dream' when they reported attaining lucidity and remembered their intention to manifest a healing experience within the dreamscape.

Results

Of eight participants experiencing healing lucid dreams, four were able to provide usable saliva samples. Statistical tests on these four participants were not significant because of low power. However, nonsignificant positive associations were observed between experiencing more healing lucid dreams and increased waking sAA slope.

Conclusion

The results did not reveal a consistent effect of healing lucid dreams on waking sAA slope. Identifying meaningful patterns in this relationship will require larger samples and more stringent control over saliva collection procedures in future studies.

Biological and psychological predictors of cognitive function in breast cancer patients before surgery

PURPOSE

Research suggests that cancer-related cognitive impairment (CRCI) can occur before breast cancer (BC) treatment. The limited extant evidence suggests the underlying mechanisms could be stress-related. Potential psychological and biological predictors of CRCI prior to any BC treatment were examined.

METHODS

112 treatment-naïve women with BC and 67 healthy controls (HC) completed a neuropsychological test battery to assess cognitive impairment and a self-report battery to assess cognitive complaints, cancer-related stress, depressive and anxiety symptoms. Morning and evening cortisol and α-amylase were collected from saliva. Multilinear regressions were conducted.

RESULTS

Treatment-naïve BC patients were more frequently impaired in verbal memory and processing speed and reported more cognitive complaints (all p < .001) than HC. BC patients and HC did not differ in overall cognitive impairment (p = .21). Steeper α-amylase, lower cancer-related stress and younger age was associated with better overall cognitive function in treatment-naïve BC patients. Higher depressive symptoms predicted higher levels of cognitive complaints in BC patients.

CONCLUSION

Overall, these findings suggest that stress plays a role in CRCI. This study is the first to associate α-amylase with cognitive function in cancer patients, informing future research. The findings on impairment in processing speed and verbal memory among treatment-naïve BC highlight the need to screen for such impairments among BC patients and indicate that future studies on CRCI should include baseline assessments prior to BC treatment. If replicated, these findings could inform the development and testing of appropriate interventions to decrease CRCI among cancer patients.

CLINICAL TRIALS REGISTRATION NUMBER

NCT04418856, date of registration: 06.05.2020.

Acute stress does not modulate selective attention in a composite letter task

Acute stress has been demonstrated to affect a diverse array of attentional processes, one of which is selective attention. Selective attention refers to the cognitive process of deliberately allocating attentional resources to a specific stimulus, while ignoring other, distracting stimuli. While catecholamines have been shown to narrow attention, investigations on the influence of the stress hormone cortisol have yielded ambiguous results. We conducted two separate studies utilizing different laboratory stress induction paradigms to examine if cortisol influences the ability to selectively attend to local or global elements of a visual stimulus. In Study 1, 72 healthy young men took part either in the stressful Socially Evaluated Cold Pressor Test (SECPT) or a non-stressful (warm water) control, before being exposed to a composite letter task (CLT). Study 2 comprised a sample of 72 healthy young men and women and made use of a modified version of the Trier Social Stress Test (TSST) as well as a non-stressful control version, the friendly-TSST (f-TSST). Via endocrine, physiological, and subjective markers, we confirmed a successful stress induction. As verified with Bayesian statistics, stress did not affect selective attention in neither of the two studies. Furthermore, we were able to replicate the previously demonstrated absence of global precedence for composite figures composed of letters. Our results offer novel insights into the temporal dynamics of the effects of acute stress on attentional processes. Future studies should manipulate the timing of stress induction and investigate the effects of stress on letter vs. non-letter composite figures to shed further light on the underlying mechanisms.

Nociception related biomolecules in the adult human saliva: A scoping review with additional quantitative focus on cortisol

Nociception related salivary biomolecules can be useful patients who are not able to self-report pain. We present the existing evidence on this topic using the PRISMA-ScR guidelines and a more focused analysis of cortisol change after cold pain induction using the direction of effect analysis combined with risk of bias analysis using ROBINS-I. Five data bases were searched systematically for articles on adults with acute pain secondary to disease, injury, or experimentally induced pain. Forty three articles met the inclusion criteria for the general review and 11 of these were included in the cortisol-cold pain analysis. Salivary melatonin, kallikreins, pro-inflammatory cytokines, soluable TNF-α receptor II, secretory IgA, testosterone, salivary α-amylase (sAA) and, most commonly, cortisol have been studied in relation to acute pain. There is greatest information about cortisol and sAA which both rise after cold pain when compared with other modalities. Where participants have been subjected to both pain and stress, stress is consistently a more reliable predictor of salivary biomarker change than pain. There remain considerable challenges in identifying biomarkers that can be used in clinical practice to guide the measurement of nociception and treatment of pain. Standardization of methodology and researchers' greater awareness of the factors that affect salivary biomolecule concentrations are needed to improve our understanding of this field towards creating a clinically relevant body of evidence.

The impact of virtual reality scenes on stress response characteristics of individuals with different personality traits

Virtual reality based physical stress (VRPS) paradigms could eliminate the influence of social factors on participants, and it may be a desirable tool to explore the impact of personality traits on stress levels. In this study, we attempt to explore the effects of VRPS on stress response among individuals with different personality traits. Forty male participants with an average age of 22.79 ± 0.41 years were divided into two groups based on Harm Avoidance (HA) scores of Tridimensional Personality Questionnaire (TPQ), referred to as the Low-HA group and the High-HA group. The stress levels of the participants were assessed using salivary α-amylase (sAA) activity and heart rate variability (HRV) indices pre- and post-stress. The influence of personality traits on stress response among different groups was analyzed. VRPS significantly affected the sAA activity and HRV indicators of both groups. During and after stress, there were significant differences in sAA activity and HRV indicators between the two groups. The sAA levels and HRV indices of the Low-HA group were lower than those of the High-HA group. Furthermore, sAA levels and HRV indices were correlated with the scores of TPQ. VRPS scenarios elicit different stress responses on individuals with different harm avoidance personality traits. Stress evaluation based on VR scenarios presents potential in personality trait assessments, particularly for distinguishing between individuals with low and high HA tendencies.

Development of enzyme-inorganic hybrid nanoflower-modified electrodes and a smartphone-controlled electrochemical analyzer for point-of-care testing of salivary amylase in saliva

Quantitation of salivary alpha-amylase (sAA) plays a significant role in not only theoretical studies but also clinical practice. This study reports a quantitative point-of-care testing (POCT) system for sAA quantitation anywhere, anytime and by anyone, which consists of customized electrodes and a smartphone-controlled electrochemical analyzer. Organic-inorganic hybrid nanoflowers (NFs) encapsulating α-glucosidase (AG) and glucose dehydrogenase (GDH) have been synthesized and modified onto screen-printed electrodes (SPCEs) to fabricate the customized electrodes. The SPCEs integrated with the smartphone-controlled electrochemical analyzer exhibit good analytical performance for sAA with a low detection limit of 5.02 U mL-1 and a wide dynamic range of 100-2000 U mL-1 using chronoamperometry. The reported POCT system has been successfully demonstrated for quantitation of sAA in clinical saliva samples, and the quantitation results correlated well with those of the Bernfeld method which is extensively used in clinics. More importantly, this study reveals the great potential of sAA as an early warning indicator of abnormal glucose metabolism in obese individuals. Considering the non-invasive saliva sampling process as well as the easy-to-use and cost-effectiveness features of this quantitative POCT system, quantitation of salivary sAA at home by laypersons might become an appealing choice for obese individuals to monitor their glucose metabolism status anytime.

Liquid foams as sensors for the detection of biomarkers

Bioassays are widely used in healthcare to detect and quantify biomarkers, such as molecules or enzymes, which are crucial in monitoring diseases and health conditions. In developed countries, healthcare professionals use specialized reagents and equipment's to perform these bioassays. However, in less-industrialized countries, the creation of low cost, fast, and technically simple bioassays is required. Herein, we propose a simple approach for detecting biochemical markers using host-guest complexes containing a surfactant. When the biochemical marker is present, the host-guest complex is disrupted, releasing the surfactant and producing foam. The read-out mechanism relies on the change of foam volume as function of biomarker concentration. This change is quantifiable by the naked eye and can be measured with a simple ruler. We claim that the use of foams as sensing tool is an attractive, inexpensive, fast, and easy to handle on-site detection method.

Psychologically aggressive parenting and later aggression: Salivary alpha-amylase reactivity and sex as moderators

Psychologically aggressive parenting (PAP) exposure negatively affects children's development of aggression. Nevertheless, not all children exposed to PAP display aggressive behaviors. Sympathetic nervous system (SNS) activity may influence the impact of early adversity on aggression. This study examines whether SNS reactivity and sex moderate the link between psychologically aggressive parenting (PAP) during childhood and later aggression. Emerging adults (N = 182, mean age = 19.03 years, 53 % female) retrospectively reported on their childhood PAP and current aggression. Salivary alpha-amylase (sAA) collected from a social stress task indexed SNS reactivity to stress. Childhood PAP was associated with emerging adulthood anger, hostility, physical, and verbal aggression. Moreover, males were more likely to exhibit anger, verbal, and physical aggression and had higher levels of sAA reactivity than females. A significant three-way interaction between childhood PAP, sAA reactivity, and sex accounted for participants' current verbal aggression. The link between childhood PAP and later verbal aggression was stronger for males at higher levels of sAA reactivity. Females with higher levels of sAA reactivity displayed lower levels of verbal aggression regardless of PAP exposure. Males and females with lower levels of sAA reactivity were at elevated risk for verbal aggression regardless of PAP exposure. Moreover, we found a significant two-way interaction between PAP and sex on anger, such that higher levels of PAP exposure were associated with more anger among males, but not females. These findings highlight the importance of examining interactions between biological and environmental factors and sex in accounting for later aggression.

Physiological stress reactivity and self-harm: A meta-analysis

OBJECTIVE

Self-harm is associated with alterations in the psychobiological stress response. Specifically, the reactivity of the autonomic nervous system (ANS) and the endocrine hypothalamic-pituitary-adrenal (HPA) axis may differ in individuals who engage in self-harm. However, evidence in this regard is inconsistent.

BACKGROUND

We conducted a preregistered random-effects meta-analysis of sympathetic ANS, parasympathetic ANS, sympathetic-parasympathetic, i.e., mixed-influence ANS, and HPA axis reactivity following laboratory stress exposure in individuals who engage in self-harm and controls. Stress exposure consisted of paradigms using either social-evaluative (e.g., TSST), emotional (e.g., negatively valenced visual stimuli), or physical (e.g., cold pressor test) challenges. A total of 29 studies (self-harm: n = 954, controls: n = 1122, 74% females) were included in the analysis.

RESULTS

Regarding ANS reactivity to stress, no differences emerged between the two groups. However, parasympathetic ANS activity was lower before stress (g = -0.30, CI -0.51 to -0.09) and after stressor cessation (g = 0.54, CI -1.07 to -0.01) in the self-harm group compared to controls. Regarding HPA axis reactivity, individuals who engage in self-harm showed significantly lower cortisol responses to stress than did controls (g = -0.26, CI -0.45 to -0.08). After stressor cessation (i.e., during stress recovery), cortisol was also lower in individuals who engage in self-harm compared to controls (g = -0.26, CI -0.43 to -0.08).

CONCLUSIONS

Lower basal parasympathetic ANS activity and flattened cortisol responses indicate dysregulation of psychobiological stress systems in individuals who engage in self-harm. A better understanding of the psychobiological underpinnings of self-harm may allow for the establishment of biomarkers of risk stratification and treatment monitoring in affected individuals.

Effects of participant-selected versus researcher-selected music on stress and mood - The role of gender

OBJECTIVE

Previous research suggests differential effects of participant-selected (PS) vs. researcher-selected (RS) music on emotional responses to music listening. This study investigates whether such selection strategies, as well as gender, influence (1) stress and (2) mood responses. Additionally, we examine the role of (3) stimulus-induced emotions and (4) emotion regulation strategies.

METHODS

Participants (N = 61) listened to auditory stimuli (PS music, RS music, sound of lapping water (LW); randomized) on three days and underwent a cold pressor test (CPT) while listening. Stress parameters (subjective acute stress, heart rate, parameter RMSSD, salivary alpha-amylase, salivary cortisol), mood dimensions (calmness, valence, energetic arousal), emotions, and emotion regulation strategies were measured. Multilevel and mediation analyses were conducted.

RESULTS

(1) There were no direct effects of selection strategy or gender on stress responses, but interaction effects indicated that women showed the strongest subjective stress response and the longest HR recovery with PS music, while men showed the lowest HR response to the CPT with PS music. (2) No mood differences emerged between PS and RS music overall. Women showed stronger variability in calmness overall as well as perceived higher arousal when listening to PS music compared to men. (3) Higher stimulus-induced anger in men compared to women and with LW compared to PS was associated with lower calmness and valence, while no consistent pattern emerged for the stress responses. (4) Women scored higher on reappraisal, associated with a decrease in parasympathetic activity, whereas men scored higher on suppression, associated with an increase in endocrine activity.

CONCLUSIONS

Music selection and gender appear to have no direct impact on stress and mood responses overall, although men tend to benefit more from self-selected music than women. Our findings provide first indications that avoiding music stimuli that induce anger may facilitate mood management via music. Furthermore, finding alternative emotion regulation strategies to the strategy of suppression may be a helpful approach to improve music-based stress management.

Short-Wavelength Light-Blocking Filters and Oral Melatonin Administration in Patients With Retinitis Pigmentosa: Protocol for a Randomized Controlled Trial

BACKGROUND

The medical community is beginning to recognize that retinitis pigmentosa (RP), due to its disabling progression, eventually leads to a reduction in the patient´s quality of life, a direct economic impact, and an increase in the burden on the health care system. There is no curative treatment for the origin of the disease, and most of the current interventions fail in reducing the associated negative psychological states, such as anxiety and depression, which lead to increased variability of vision and pose a continuous threat to the patient's independence.

OBJECTIVE

The aim of this study is to assess the effect of oral melatonin (OM) administration alone and combined with short-wavelength light (SWL)-blocking filters on patients with RP and test their effectiveness in improving the level of stress and sleep problems in many of these patients.

METHODS

We have developed a low-cost therapy protocol for patients with RP with sleep disorders and negative psychological stress. Patients will be randomized to receive a combined intervention with SWL-blocking filters and OM, SWL-blocking filters alone, or OM alone. There will also be a nonintervention arm as a control group. This study will be conducted across 2 retinal units in patients with RP with sleep disorders and high perceived stress and anxiety score reports. Patients will be assessed in the preintervention period, weekly during the 4 weeks of intervention, and then at 6 months postintervention. The primary outcomes are the differences in changes from baseline to postintervention in hormone release (α-amylase, cortisol, and melatonin) and sleep quality, as measured with the visual analog scale. Secondary outcome measures include clinical macular changes, as measured with optical coherence tomography and optical coherence tomography angiography; retinal function, as measured using the visual field and best-corrected visual acuity; sleep data collected from personal wearables; and several patient-reported variables, such as self-recorded sleep diaries, quality of life, perceived stress, and functional status.

RESULTS

This project is still a study protocol and has not yet started. Bibliographic research for information for its justification began in 2020, and this working group is currently seeking start-up funding. As soon as we have the necessary means, we will proceed with the registration and organization prior to the preliminary phase.

CONCLUSIONS

In this feasibility randomized clinical controlled trial, we will compare the effects of SWL blocking alone, administration of OM alone, and a combined intervention with both in patients with RP. We present this study so that it may be replicated and incorporated into future studies at other institutions, as well as applied to additional inherited retinal dystrophies. The goal of presenting this protocol is to aid recent efforts in reducing the impact of sleeping disorders and other psychological disorders on the quality of life in patients with RP and recovering their self-autonomy. In addition, the results of this study will represent a significant step toward developing a novel low-cost therapy for patients with RP and validating a novel therapeutic target.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/49196.

Effects of Linpan nature therapy on health benefits in older women with and without hypertension

Background

Nature therapy can significantly benefit the physiology and psychology of middle-aged and older people, but previous studies have focused on forest environments. The restoration potential of rural environments in urban fringe areas, which are more accessible to older people on a daily basis, has not been fully studied. This study assessed the effects of nature therapy on the physical and mental health of older women in a rural setting (locally known as Linpan) in the urban fringe area of Chengdu, China.

Methods

We recruited a total of 60 older women (65.3 ± 5.5 years old) living in cities for 3 days of nature therapy in the winter (30 subjects) and spring (30 subjects), including 20 hypertensive patients.

Results

The results showed that the overall blood pressure, pulse and sleep dysfunction rating scores of the participants were significantly lower than the pretest levels, and the finger blood oxygen saturation, mid-day salivary alpha-amylase and cortisol were increased post-treatment. Increases in these biomarker indicates and increase in stress. There were significant differences in the changes in systolic blood pressure between the hypertension group (HTN) and the normal group (normal) (HTN decreased by 8.8%, normal decreased by 5.4%), salivary alpha-amylase content (HTN decreased by 0.3%, normal increased by 16.9%), and sleep dysfunction rating scores (HTN decreased by 59.6%, normal decreased by 54%). The decreases in systolic blood pressure and pulse in the winter group were higher than those in the spring group by 1.8 and 4.4%, respectively, while the increases in salivary alpha-amylase content and salivary cortisol content were lower than those in the spring group by 11.7 and 11.2%, respectively, and the decrease in sleep dysfunction rating scores was lower than that in the spring group by 7.1%.

Conclusion

Our study concluded that nature therapy based on various health activities in the Linpan has significant health effects on older women. It can regulate blood pressure and pulse in older women, relieve cardiovascular disease, improve sleep quality. Meanwhile, older women with high blood pressure experienced a more significant effect than the healthy group.

The impact of physical exercise on the consolidation of fear extinction memories

Based on the mechanisms of fear extinction, exposure therapy is the most common treatment for anxiety disorders. However, extinguished fear responses can reemerge even after successful treatment. Novel interventions enhancing exposure therapy efficacy are therefore critically needed. Physical exercise improves learning and memory and was also shown to enhance extinction processes. This study tested whether physical exercise following fear extinction training improves the consolidation of extinction memories. Sixty healthy men underwent a differential fearconditioning paradigm with fear acquisition training on day 1 and fear extinction training followed by an exercise or resting control intervention on day 2. On day 3, retrieval and reinstatement were tested including two additional but perceptually similar stimuli to explore the generalization of exercise effects. Exercise significantly increased heart rate, salivary alpha amylase, and cortisol, indicating successful exercise manipulation. Contrary to our expectations, exercise did not enhance but rather impaired extinction memory retrieval on the next day, evidenced by significantly stronger differential skin conductance responses (SCRs) and pupil dilation (PD). Importantly, although conditioned fear responses were successfully acquired, they did not fully extinguish, explaining why exercise might have boosted the consolidation of the original fear memory trace instead. Additionally, stronger differential SCRs and PD toward the novel stimuli suggest that the memory enhancing effects of exercise also generalized to perceptually similar stimuli. Together, these findings indicate that physical exercise can facilitate both the long-term retrievability and generalization of extinction memories, but presumably only when extinction was successful in the first place.

Moderate-to-vigorous intensity cycling exercise immediately after visual learning enhances delayed recognition memory performance

A single bout of acute aerobic exercise has been shown to improve long-term memory, though it is unclear if exercise before learning or after learning is optimal for memory enhancement. Although some research has demonstrated that exercise before learning is ideal, investigations have consistently shown that acute arousal post-learning is a powerful memory enhancer. Therefore, the purpose of this investigation was to compare the effects of self-perceived hard cycling before or after learning on recognition memory for emotional and neutral images, and examine the relationship between central noradrenergic activity and memory performance. Seventy-two males and females (18-35 years of age) participated in this between-subjects study. Participants were randomly assigned to one of the following groups: exercise before learning, exercise after learning, and control. Participants in the exercise groups engaged in 20 min of cycling at a rating of perceived exertion (RPE) of 15 ("hard") on the Borg RPE scale before or after viewing a series of 90 pleasant, unpleasant, and neutral images (30 each). Participants in the control group engaged in no exercise before or after image viewing. At several time points throughout the experiment, saliva was collected to measure salivary alpha amylase (sAA), a marker of central noradrenergic activity. One-week later, recognition memory was assessed where participants viewed 180 images (90 new) and had to identify which images were previously viewed. Participants in the exercise after learning group had significantly higher recognition memory compared to the control group, but this was not seen with exercise before learning. sAA was not correlated with memory in any group, though it did increase during exercise. These results demonstrate that acute self-perceived hard cycling post-learning, but not pre-learning, improves recognition memory, though this was unrelated to the exercise-induced increase in central noradrenergic activity as measured in saliva.

Blunted neurobiological reactivity and attentional bias to threat underlie stress-related disorders in women survivors of intimate partner violence

BACKGROUND

Intimate partner violence (IPV) alters women's neurobiological stress response systems. We propose that individual differences early in the attentional processing of threats are associated with these neurobiological mechanisms and contribute to mental illness in this population.

METHODS

We assessed attentional bias in relation to threat (AB) in women survivors of IPV (n = 69) and controls (n = 36), and examined overall cortisol secretion using hair cortisol (HC), and stress responsiveness measuring salivary cortisol and α-amylase (sAA) before (T0), and after (T1, T2) an acute psychosocial stress task (Trier Social Stress Test). We used repeated-measures ANCOVAs to explore the associations between Group (IPV, control) and AB with acute stress response, and regression models to examine the associations with mental health symptoms.

RESULTS

There were no between-group differences in HC levels. An interaction between Group and AB was found regarding cortisol reactivity (p < 0.05). IPV women with threat avoidance AB showed a blunted cortisol response compared to controls and to IPV participants with threat vigilance AB. The association between sAA reactivity and the interaction between Group, AB, and time approached significance (p = 0.07), with a trend to lower sAA levels particularly in IPV women with threat avoidance AB. Group and cortisol reactivity were associated with symptoms of depression, generalized anxiety, and post-traumatic stress disorder (8-20% explained variance).

CONCLUSIONS

Threat avoidance AB is associated with blunted acute cortisol response among women exposed to chronic stress (IPV). Experiencing IPV and acute cortisol response appear to be clearly implicated in long-term mental health problems.

Is burning mouth syndrome associated with stress? A meta-analysis

BACKGROUND

Some studies have shown burning mouth syndrome (BMS) as comorbid psychosocial and psychiatric disorders, and as well, pointed at stress as a major risk factor.

OBJECTIVE

The aim of this meta-analysis was to answer the following question: 'Is there an association between BMS and stress, compared to healthy controls?'

METHODS

Two reviewers searched for the effect of stress in BMS and published on five main databases and three from the grey literature. Various questionnaires and biomarkers were analysed. Of the 2489 selected articles, 30 met the inclusion criteria. Studies englobed questionnaires, such as Perceived Stress Questionnaire, Lipp Stress Symptoms Inventory, Holmes-Rahe scale, Depression, Anxiety, and Stress Scale (DASS-21), Recent Experience Test; and various biomarkers, such as cortisol, opiorphin, IgA, α-amylase and interleukins.

RESULTS

In all studies with questionnaires, stress was significantly increased in the BMS group vs. control. Patients with BMS presented 25.73% higher cortisol levels, 28.17% higher IgA levels and 40.62% higher α-amylase levels than controls. Meta-analysis found that BMS subjects presented 3.01 nmoL/L [0.53; 5.50] higher cortisol levels, 84.35 kU/L [15.00; 153.71] higher α-amylase levels, 29.25 mg/mL [9.86; 48.64] higher IgA levels and 258.59 pg/mL [59.24; 457.94] higher IL-8 levels than control. No differences were found for opiorphin concentration in ng/mL [-0.96; 2.53]. For interleukins, no differences were founded for IL-1 β, IL-2, IL-4, IL-6, IL-8, IL-10 and TNF-α.

CONCLUSION

Based on the available evidence, this meta-analysis suggests more stress factors in questionnaire-based studies, and higher levels of cortisol, α-amylase, IgA and IL-8 biomarkers in BMS subjects than controls.

Physiological response to pain in female adolescents with nonsuicidal self-injury as a function of severity

BACKGROUND

Preliminary evidence indicates altered hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS) response to experimental pain in individuals with nonsuicidal self-injury (NSSI). This study investigated effects of NSSI severity and severity of psychopathology on the HPA axis and ANS response to pain.

METHODS

N = 164 adolescents with NSSI and n = 45 healthy controls received heat pain stimulation. Salivary cortisol, α-amylase and blood pressure were repeatedly assessed before and after painful stimulation. Heart rate (HR) and heart rate variability (HRV) were assessed continuously. NSSI severity and comorbid psychopathology were derived from diagnostic assessments. Main and interaction effects of time of measurement and NSSI severity, adjusted for severity of adverse childhood experiences, borderline personality disorder and depression, on HPA axis and ANS response to pain were examined using regression analyses.

RESULTS

Increasing NSSI severity predicted an increasing cortisol response (χ2(3) = 12.09, p = .007) to pain. After adjusting for comorbid psychopathology, greater NSSI severity predicted decreased α-amylase levels following pain (χ2(3) = 10.47, p = .015), and decreased HR (χ2(2) = 8.53, p = .014) and increased HRV(χ2(2) = 13.43, p = .001) response to pain.

LIMITATIONS

Future research should implement several NSSI severity indicators, potentially revealing complex associations with the physiological response to pain. Assessing physiological responses to pain in NSSI in a naturalistic setting presents a promising avenue for future research in NSI.

CONCLUSIONS

Findings indicate an increased pain-related HPA axis response and an ANS response characterized by reduced sympathetic and increased parasympathetic activity associated with NSSI severity. Results support claims for dimensional approaches to NSSI and its related psychopathology alongside shared, underlying neurobiological correlates.

Changes in stress pathways as a possible mechanism of aerobic exercise training on brain health: a scoping review of existing studies

Physical activity (PA) in the form of aerobic exercise (AE) preserves and improves neurocognitive function across the lifespan. However, a mechanistic understanding of the pathways by which aerobic exercise impacts brain health is still lacking, particularly with respect to stress-related pathways. One mechanistic hypothesis is that AE improves neurocognitive health in part by modifying circulating levels of stress-related hormones and signaling factors associated with the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS), as commonly measured by the biomarkers cortisol (CORT) and salivary α-amylase (sAA). Thus, this hypothesis predicts that changes in stress biomarkers, such as CORT and sAA, are possible explanatory pathways mediating the positive effects of AE on neurocognitive health. In the present review article, we provide a summary of available studies examining the possibility that exercise-induced changes to stress biomarkers could partly account for exercise-related improvements in neurocognitive health. Our review indicates that despite the intuitive appeal of this hypothesis, there is insufficient evidence available to conclude that chronic and habitual AE affects neurocognitive health by altering stress biomarker pathways. The cross-sectional nature of the majority of reviewed studies highlights the need for well-controlled studies to adequately test this hypothesis.

How is music listening purpose related to stress recovery? - two preliminary studies in men and women

Introduction

Studies have suggested that listening to music can reduce psychological and biological responses to a stressor. However, it is unclear whether music has the same effect on stress recovery. According to field studies, people commonly use music in daily life for the specific purpose of relaxation. We explored whether individuals who generally use music for relaxation purposes show improved recovery from an acute stressor.

Methods

In two independent studies, twenty-seven healthy female participants (Mage = 24.07) (Study 1) and twenty-one healthy male participants (Mage = 23.52) (Study 2) were separated into two groups based on their frequency of using music for relaxation purposes (low vs. high). All participants underwent a lab-based psychosocial stress test. Subjective stress levels were measured using visual analogue scales. Salivary cortisol and salivary alpha-amylase were measured to assess endocrine and autonomic stress responses, respectively. Subjective stress levels and saliva samples were measured nine times throughout the stress induction and recovery procedure. Chronic stress levels were assessed using the Perceived Stress Scale and the Screening Scale of Chronic Stress.

Results

No significant differences were observed in subjective stress levels, salivary alpha-amylase activity, or cortisol concentration between the two groups in either of the two studies. Further analyses revealed that among male participants, increased use of music for relaxation purposes was related to more chronic stress levels (t (10.46) = 2.45, p = 0.03, r = 0.60), whereas female participants exhibited a trend in the opposite direction (t (13.94) = -1.92, p = 0.07, r = 0.46).

Discussion

Contrary to our expectations, the results indicate that habitual music listening for relaxation purposes is not associated with improved recovery from a stressor. However, due to the small sample size, future exploration is necessary to enhance the statistical power of the results of the study.

Family instability, parenting, and child externalizing problems: Moderation by maternal sympathetic stress reactivity

This multi-method longitudinal study evaluated how changes in maternal sensitive parenting may operate as an indirect factor linking family instability and the development of child externalizing problems over time. This study also investigated how mothers' stress reactivity within the sympathetic nervous system (SNS) may moderate the association between family instability and the development of maternal sensitivity. Participants were 235 families with a young child (Mage = 2.97 years at the first measurement occasion) and these families were followed for two annual measurement occasions. Maternal sensitivity was observed during two discipline tasks (i.e., forbidden toy, discipline discussion tasks), and maternal SNS stress reactivity was indicated by their salivary alpha-amylase (sAA) reactivity to an interpersonal stressor. Findings revealed significant direct effects of family instability and family instability-x-sAA reactivity interaction in association with the change in maternal sensitivity over time. For both tasks, mothers with greater sAA reactivity exhibited stronger associations between family instability and the growth of their sensitivity. Tests of indirect effects indicated that change in maternal sensitivity operated as an indirect factor between family instability-x-sAA reactivity interaction and the change in child externalizing problems. The present findings have important implications for understanding parental and child sequelae associated with unstable family contexts.

Sympathetic nervous system responses to acute psychosocial stress in male physicians with clinical burnout

BACKGROUND

Occupational burnout has been associated with an increased risk of cardiovascular disease, with sympathetic nervous system (SNS) dysfunction as one explanation. This study examined the effects of burnout on responses of SNS activity measures to acute psychosocial stress in male physicians, a population at risk for burnout.

METHODS

Study participants were 60 male physicians, 30 with clinical burnout, assessed with the Maslach Burnout Inventory, and 30 without burnout (controls). All participants underwent the 15-min Trier Social Stress Test. Heart rate, blood pressure, salivary alpha-amylase, and plasma levels of epinephrine (EPI) and norepinephrine were assessed pre-stress, immediately post-stress, and 15 min and 45 min post-stress.

RESULTS

Physicians with burnout and controls differed in EPI changes over time, controlling for age, job stress and anxiety symptoms (F (3,147) = 5.18, p = .002 for 'Time by Group' interaction; η2p = .096). Burnout was associated with a smaller increase in EPI from pre-stress to immediately post-stress (r(54) = -.40, p = .004). The emotional exhaustion dimension of burnout was a significant driver of this effect. The area under the curve with respect to increase in EPI was also smaller in the burnout group (F (1,49) = 6.06, p = .017, η2p = .110). Group differences were not significant for the other SNS activity measures.

CONCLUSIONS

Burnout may be linked to dysfunction of the sympathoadrenal medullary (SAM) system, when exposed to acute psychosocial stress. In keeping with the allostatic load concept, an insufficient SAM stress response in burnout could potentially contribute to cardiovascular disease.

Biological stress responses to multitasking and work interruptions: A randomized controlled trial

In the course of digitalization, new stressors are emerging. In modern working and living environments, two ubiquitous, technology-mediated stressors are multitasking demands and work interruptions. However, biological stress response patterns to multitasking and work interruptions have been sparsely investigated so far. We thus aimed to comprehensively assess biological stress response patterns to both stressors and, additionally, test whether responses differ between digital and partially non-digital settings. A controlled experimental set-up was established and humans' biological markers of the Sympathetic Nervous System (SNS), the hypothalamic-pituitary adrenal (HPA) axis, and the immune system were assessed. N = 186 healthy participants (mean age: 23.2 ± 4.3 years, 74.7% female, body mass-index: 22.3 ± 3.1 kg/m2) took part in this pre-registered study. Each participant was randomly assigned to one of 6 experimental conditions (1 digital single-task, 3 dual-tasks [2 parallel tasks and 1 interruption], 1 multitasking, and 1 passive, control condition). Each one of the dual-tasking as well as the multitasking conditions included a non-digital sub-task, i.e., performing a task in presence of an examiner. All other conditions involved digital tasks only. Salivary alpha-amylase (sAA) levels as a marker for SNS reactivity significantly changed in work interruptions, parallel dual-tasking, and multitasking conditions. No changes were found for control conditions. Furthermore, no significant changes over time and no differences between the conditions were identified for three biological markers: cortisol as marker for HPA axis activity as well as for two immune system markers (secretory Immunoglobulin-A, C-reactive protein). A time course similar to sAA was found for perceived stress: with increases during task execution and decreases afterwards in multitasking and parallel dual-tasking. Yet, it did not change for the work interruption, passive control, and single-tasking condition. Overall, our findings show that dual- and multitasking are perceived as stressful and are associated with an activation of the SNS, but not with responses of HPA axis or immune system. This was consistent for digital as well as partially digital task demands. Our findings will also inform future research into the differential stress effects of digital and non-digital tasks to advance our understanding of biological stress response-patterns to multitasking and work interruptions. Therefore, our findings are highly relevant for understanding the long-term biological health effects of stress in modern (digitalized) environments.

Effect of transcutaneous vagus nerve stimulation on stress-reactive neuroendocrine measures in a sample of persons with temporal lobe epilepsy

OBJECTIVE

Dysregulation of stress-reactive neuroendocrine measures, as well as subjective stress, have been found to worsen epilepsy. Transcutaneous vagus nerve stimulation (tVNS) is a relatively new treatment option for epilepsy. We were interested in its effect on the activity of the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS) as well as subjective stress and tiredness in patients with temporal lobe epilepsy (TLE).

METHODS

Twenty patients (age 44 ± 11 years, 13 women) were enrolled in the study. They were free of seizures for more than 1 year. All took part in two sessions with 4 h of stimulation (tVNS vs. sham) in a randomized order. Saliva samples and subjective stress and tiredness levels were measured at five time points each session (before and after stimulation and three time points every hour in between). Data were analyzed using repeated measures analysis of variance as well as paired t-tests.

RESULTS

There was a dampened salivary cortisol (sCort) decrease during tVNS (time × condition effect: F[2.38, 38.15]  = 6.50, P = 0.002, partial η2  = 0.29). Furthermore, we detected a dampened increase in salivary flow rate during tVNS (time × condition effect: F[3.28, 55.67]  = 2.82, P = 0.043, partial η2  = 0.14). There was neither a difference in overall sCort or salivary alpha-amylase (sAA) levels nor in subjective stress or tiredness levels between conditions. sAA levels at the last measurement point were slightly higher during tVNS (t(19)  = 2.26, P = 0.035, d = 0.51), but this effect failed to reach significance when controlled for multiple comparisons.

SIGNIFICANCE

Our results partially support that tVNS influences the regulation of stress-reactive neuroendocrine systems (namely the HPA axis and ANS) in epilepsy. More research with larger samples is needed on the difference between short-term and repeated long-term stimulation.

Feasibility of biomarkers to measure stress, burnout and fatigue in emergency nurses: a cross-sectional study

INTRODUCTION

Retaining nurses in the workforce is an urgent concern in healthcare. Emergency nurses report high levels of stress and burnout, however, there is no gold standard of how to measure these responses. This study aims to measure stress, burnout, and fatigue in emergency nurses using biomarkers and psychometric instruments. Biomarkers will be used to better understand nurses' levels of stress and burnout and to assess the feasibility of using biomarkers as a viable stress measurement tool in a real-world setting.

METHODS AND ANALYSIS

A two stage cross-sectional design to measure stress, burnout and fatigue in emergency nurses while they work is proposed. All registered and enrolled nurses working in the emergency department from four hospitals in Australia will be invited to participate. Validated psychometric tools will be used in stage 1 to measure depression, anxiety, acute stress, chronic stress, burnout and fatigue. Biomarkers comprising hair cortisol, saliva alpha amylase and heart rate variability will be collected as an objective measure of stress and burnout in stage 2 over one working shift per participant. Written consent will be sought for stage 2 where nurses will provide one hair sample, wear a heart rate sensor and be asked to collect their saliva at three different time points of one shift. Data analysis will measure the domains of acute stress, chronic stress and burnout and explore relationships and correlation between psychometric measures and biomarkers.

ETHICS AND DISSEMINATION

Ethics approval obtained from the Human Research Ethics Committee of the Hunter New England Local Health District (approval number: HREC/2020/ETH01684) and University of Newcastle HREC (H-2022-0169). Results will be reported in peer-reviewed publications using the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Public dissemination will occur by presenting at conferences and to the participating local health district.

Enhanced memory for central visual and auditory elements experienced during a stressful episode

Acute psychosocial stress has been shown to benefit memory for central visual elements of a stressful episode. Here, we aimed at investigating whether this effect is accompanied by improved visual memory for the committee members in a modified version of the Trier Social Stress Test (TSST). Specifically, we tested participants´ recognition memory for accessories located on the bodies of the committee members, as well as their faces. Moreover, we investigated how stress influences memories for the content of the verbal interactions. That is, we studied how well participants remembered factual information associated with the main stress source, like name, age, and position of the committee members, as well as how accurately they could recite the exact wording of phrases used by them. In a counterbalanced 2 × 2 design, 77 men and women took part either in a stressful or non-stressful version of the TSST. While stressed participants better remembered personal information about the committee members than non-stressed participants, no differences in memory for the correct wording of phrases could be observed. Furthermore, in line with our hypothesis, stressed participants better remembered central, but not peripheral visual stimuli, compared to non-stressed participants, while, contrary to our expectations, stress did neither affect memory for objects located on the bodies of the committee members nor their faces. Our results are in line with the theory of enhanced memory binding under stress and extend previous results regarding improved memory for central visual elements encoded under stress to auditory learning material associated with the stressor.

Slow Breathing Reduces Biomarkers of Stress in Response to a Virtual Reality Active Shooter Training Drill

Tactical occupations regularly encounter life-threatening situations while on duty. Although these occupations are often trained to utilize slow breathing (SB) during intense stress, there is no evidence supporting the effects on markers of stress in response to a virtual reality active shooter training drill (VR-ASD). The purpose of the study was to determine the impact of acute SB on biomarkers of stress in response to a VR-ASD. Seventy-nine (n = 79) subjects performed either slow breathing method 1 (SB1), slow breathing method 2 (SB2), or normal breathing (control) for five minutes, both pre- and post-VR-ASD. Saliva samples were analyzed for stress markers, including α-amylase (sAA) and secretory immunoglobulin-A (SIgA). Both methods of SB resulted in significantly lower sAA concentrations at 5 (p < 0.001) and 30 min post-VR-ASD (SB1: p = 0.008; SB2: p < 0.001) compared to the control. In the control condition, the sAA concentrations were significantly elevated 5 min post-VR-ASD (p < 0.001) but did not change across time in SB1 or SB2 (p > 0.05). Thus, both SB1 and SB2 reduced the sAA response and resulted in lower concentrations post-VR-ASD. This study was pre-registered as a clinical trial ("Impact of Breathing Interventions on Stress Markers"; NCT05825846).

Clinical correlation of salivary alpha-amylase levels with pain intensity in patients undergoing emergency endodontic treatment

BACKGROUND

Pain is usually subjective and thus it is challenging to describe its characteristics such as nature, intensity, and origin. Non-invasive methods such as assessing salivary alpha-amylase (SAA) may aid the practitioner to evaluate the pain intensity. Hence, the current study aimed to correlate the levels of SAA with the pain intensity in patients presenting with varied endodontic pain levels.

METHODS

Sixty patients who presented with varied intensities of endodontic pain were selected for the present study out of which seven patients were excluded/dropped, leaving a total sample of fifty-five patients for assessment. Mandibular molar with symptomatic irreversible pulpitis without periapical pathology were included in the study. A 5ml of un-stimulated was obtained from the patients, following which the local anesthesia was administered. Root canal treatment was then performed and the pain scores at pre-operative and post-operative were recorded. Additionally, salivary samples were collected after emergency endodontic treatment and sent for sialochemical analysis. IBM.SPSS statistics software 23.0 was employed to assess the obtained data.

RESULTS

A statistically significant drop in the pain score (P < 0.001) and SAA levels (P < 0.001) were observed post-operatively in the contract to pre-operative state. A strong positive correlation was reported between SAA levels and pain scores in patients undergoing emergency endodontic treatment at both time intervals namely pre-operative (P < 0.001) and post-operative (P < 0.001).

CONCLUSION

The results of this preliminary showed a strong association between the pain score and SAA levels in patients undergoing an emergency endodontic treatment.

Physiological reactivity to acute mental stress in essential hypertension-a systematic review

Objective

Exaggerated physiological reactions to acute mental stress (AMS) are associated with hypertension (development) and have been proposed to play an important role in mediating the cardiovascular disease risk with hypertension. A variety of studies compared physiological reactivity to AMS between essential hypertensive (HT) and normotensive (NT) individuals. However, a systematic review of studies across stress-reactive physiological systems including intermediate biological risk factors for cardiovascular diseases is lacking.

Methods

We conducted a systematic literature search (PubMed) for original articles and short reports, published in English language in peer-reviewed journals in November and December 2022. We targeted studies comparing the reactivity between essential HT and NT to AMS in terms of cognitive tasks, public speaking tasks, or the combination of both, in at least one of the predefined stress-reactive physiological systems.

Results

We included a total of 58 publications. The majority of studies investigated physiological reactivity to mental stressors of mild or moderate intensity. Whereas HT seem to exhibit increased reactivity in response to mild or moderate AMS only under certain conditions (i.e., in response to mild mental stressors with specific characteristics, in an early hyperkinetic stage of HT, or with respect to certain stress systems), increased physiological reactivity in HT as compared to NT to AMS of strong intensity was observed across all investigated stress-reactive physiological systems.

Conclusion

Overall, this systematic review supports the proposed and expected generalized physiological hyperreactivity to AMS with essential hypertension, in particular to strong mental stress. Moreover, we discuss potential underlying mechanisms and highlight open questions for future research of importance for the comprehensive understanding of the observed hyperreactivity to AMS in essential hypertension.

Association between Salivary Cortisol and α-Amylase with the Psychological Profile of Patients with Oral Lichen Planus and Burning Mouth Syndrome: A Case-Control Study

The aim of our study was to assess the relationship between the concentration/activity of salivary stress biomarkers (cortisol, α-amylase) and the psychological profile of patients with oral lichen planus (OLP) and primary burning mouth syndrome (BMS). A total of 160 subjects participated in this case-control study: 60 patients with OLP; 60 patients with primary BMS; and 40 control subjects. Unstimulated whole saliva (UWS) was collected between 9 and 10 a.m. Salivary biomarkers were analyzed by enzyme-linked immunosorbent assays (ELISAs). Psychological assessment was evaluated with the Depression, Anxiety, and Stress Scale (DASS-21). The patients with primary BMS had higher salivary cortisol concentrations and α-amylase activity (0.52 vs. 0.44 µg/dL; 160,531 vs. 145,804 U/L; one-way analysis of variance (ANOVA) with post hoc Scheffe test) compared with patients with OLP. The patients with primary BMS had statistically significant higher scores for depression, anxiety, and stress compared with patients with OLP and control subjects (p < 0.001, Kruskal-Wallis test). There was a strong positive correlation between anxiety and depression, stress and depression, and stress and anxiety in patients with OLP and BMS (p < 0.001 and p < 0.001, respectively; Spearman's correlation). There was a good positive correlation between symptom intensity (pain/burning) and psychological profile (depression, anxiety, stress) in patients with primary BMS (r = 0.373, p = 0.003; r = 0.515, p < 0.001; r = 0.365, p = 0.004, respectively; Spearman's correlation). This case-control study is the first to compare the psychoendocrinological profile of patients with two different oral diseases. The patients with BMS showed a higher concentration/activity of salivary stress biomarkers (cortisol, α-amylase) and a stronger association with mental disorders compared with patients with OLP. However, an interdisciplinary psychoneuroimmunological approach is equally important in both patient groups (OLP and BMS), regardless of whether mental disorders are the cause or the consequence.

Salivary Biomarkers: Noninvasive Ways for Diagnosis of Parkinson's Disease

Finding reliable biomarkers has a crucial role in Parkinson's disease (PD) assessments. Saliva is a bodily fluid, which might be used as a source of biomarkers for PD. Our article has reviewed several publications on salivary proteins in PD patients and their potential as biomarkers. We find out that α-Syn's proportion in oligomeric form is higher in PD patients' saliva, which is potent to use as a biomarker for PD. The salivary concentration of DJ-1 and alpha-amylase is lower in PD patients. Also, substance P level is more moderate in PD patients. Although salivary flow rate is decreased in PD patients, high levels of heme oxygenase and acetylcholinesterase might be used as noninvasive biomarkers. Salivary miRNAs (miR-153, miR-223, miR-874, and miR-145-3p) are novel diagnostic biomarkers that should be given more attention.