Current status of salivary hormone analysis

Allopregnanolone in the peripartum: Correlates, concentrations, and challenges - A systematic review

BACKGROUND

Allopregnanolone (ALLO) is a metabolite of progesterone and a neuroactive steroid hormone. As a positive allosteric modulator of gamma-aminobutyric acid (GABA) receptors, ALLO seems to have antidepressant and anxiolytic effects, and was therefore approved as a specific medication for the treatment of postpartum depression in 2019. Despite the growing number of publications investigating ALLO levels, results on the biological and psychological correlates in the peripartum period remain inconsistent, possibly due to methodological challenges regarding measurement. To date, however, there is no systematic review examining the correlates, concentrations, and challenges in measuring ALLO in peripartum women.

METHOD

A systematic literature search of PubMed and PsycINFO was conducted in August 2023. Original research articles that measured ALLO concentrations in peripartum women were included. Reports were excluded if they were not original research, included non-human subjects, did not include peripartum women, did not include ALLO measurement as an outcome, included (pharmacological) interventions, constituted method validations, or used the same cohort as another study.

RESULTS

The literature search yielded 234 articles, and two articles were identified from other sources. After full-text screening, 19 articles (N = 1401) met the inclusion criteria, of which seven focused on biological correlates of ALLO and 12 on mood correlates. Of the latter, six found no association between ALLO and mood, four found a negative association, and two found a positive association. Overall, the results show an increase in ALLO levels during pregnancy and a decrease after birth, with levels then remaining low until six months postpartum. ALLO was most commonly measured in blood plasma and by gas chromatography-mass spectrometry (GC-MS). A significant matrix effect was found for blood serum and a significant method effect for radioimmunoassays (RIAs). A significant effect of time of measurement was found.

CONCLUSION

ALLO measurement shows method and matrix effects. ALLO levels are higher when measured in serum compared to in plasma, and when measured using RIA compared to other methods. Time of measurement, study design, and standardization of measurement also influence the reliability of measurement and the interpretation of results.

Salivary oxytocin changes and effect of the season in sows kept in different farrowing systems: Farrowing crate and farrowing pen with temporary crating

Alternative farrowing systems that have been developed in recent years could have a positive effect on the welfare of sows during farrowing and lactation. Oxytocin measurements in saliva may provide information about positive animal welfare status. The purpose of this study was to evaluate the changes in salivary oxytocin concentrations in sows during the lactation period in three different farrowing systems and in two different seasons. Crossbred Duroc sows (n = 34, average parity = 3.6 ± 1.80) were housed in conventional farrowing crates (FC) (n = 10) or in farrowing pens with temporary crating (TC), including SWAP (n = 12) and JFL15 (n = 12) in two different seasons: summer and winter. Saliva samples were collected for six days during lactation: days 2, 4, 12, 23, 25 (i.e., 1-day post-weaning) and 26 (i.e., 2-day post-weaning) after farrowing. Moreover, behavioral data from sows was recorded on days 2, 4, 12 and 23 after farrowing, using a 30-s scan sampling method for 3 min per pen to record the behaviors which were assessed by the same observer. The results showed that the salivary oxytocin concentrations were 472.5 pg/mL and 399.4 pg/mL higher in both TC (SWAP and JLF15, respectively) than in the FC in early-lactation period, and these differences were more pronounced in summer and at the end of lactation in winter. In terms of behavior, higher number of mother-young interactions were observed in TC than FC in early- and mid-lactation period. In conclusion, TC is associated to a higher salivary oxytocin concentration that could indicated an increased mother-young interaction, although oxytocin concentration can be influenced by other factors, such as season or day of lactation.

Salivary markers of aggression - The possible alterations in salivary hormones levels to identify perpetrators of aggression-related violence

Aggression, understood as intentional actions aimed at causing harm, remains in a direct relation with the phenomenon of interpersonal violence, especially its physical form. Creating an objective marker of aggression would be an important tool for preventing, protecting the victims and maintaining control over suspects. There have been attempts to link aggression with shifts in hormone levels, including those that can be measured in saliva, especially testosterone and cortisol. The systematic review aimed to assess changes in salivary hormone levels among perpetrators of violence, with particular emphasis on physical violence, as parameters pointing to perpetrators of violence. Following the inclusion and exclusion criteria, 22 studies were included. Most of the papers included in the analysis came from the USA and Europe. Studies typically included adults as well as children, while focusing mainly on men. Among the hormones, salivary testosterone levels were the ones analyzed most frequently. On the basis of the included studies, a meta-analysis was conducted on the relationship between aggressive behavior and the levels of concentration of testosterone and cortisol measured in saliva. Regardless of gender, individuals exhibiting aggressive behavior were proved to have significantly higher testosterone levels and lower cortisol concentrations in saliva measurements. The obtained results indicate the feasibility of using the examined parameters for initial detection of perpetrators of aggression-related violence. However, further research is necessary to more precisely determine the relationship between aggressive behavior and hormonal changes in order to determine the feasibility of using these parameters as an objective marker for early identification of perpetrators.

Oxytocin and cortisol concentrations in urine and saliva in response to physical exercise in humans

BACKGROUND

While peripheral markers of endogenous oxytocin and glucocorticoid release are widely employed in psychological and behavioural research, there remains uncertainty regarding the effectiveness of saliva and urine samples in accurately capturing fluctuating hormone levels in response to relevant stimuli. In addition, it is unclear whether and under which conditions, urinary concentrations correlate with salivary levels of oxytocin and cortisol.

METHODS

In the present study, two groups of healthy adult male and female participants (N=43) provided heart rate, saliva, and urine samples before and after exercising at different durations and intensities (3 ×10 min of running vs. 60 min of running). Effects of age, gender, cycle phase, and previous running experience were considered in the statistical analyses. Concentrations of oxytocin and cortisol were analysed in both saliva, and urine using validated assays.

RESULTS

Runners of both groups had significantly increased oxytocin concentrations in urine and saliva after running than before. Oxytocin in saliva was elevated after 10 min and peaked after 30 min of running. Only participants of the long-running group showed an increase in urinary cortisol concentrations following exercise (and only after 90 min of stimulus onset), and neither group had a significant increase in salivary cortisol levels. Oxytocin rise in urine and saliva from basal to post-run was strongly and significantly correlated, as was cortisol rise from basal to post-rest, but no correlations between absolute hormone concentrations were found for oxytocin.

CONCLUSIONS

Our results show that both urine and saliva are useful body fluids that can provide meaningful results when measuring oxytocin and cortisol concentrations after a physical stimulus. While temporal resolution may be better with salivary sampling as higher sampling frequency is possible, signal strength and robustness were better in urinary samples. Importantly, we report a strong correlation between the magnitude of change in oxytocin and cortisol concentrations in urine and saliva following physical exercise, but no correlations between absolute oxytocin concentrations in the two substrates.

Autonomic nervous system and endocrine system response to upper or lower cervical spine mobilization in males with persistent post-concussion symptoms: a proof-of-concept trial

INTRODUCTION

The peripheral stress response, consisting of the autonomic nervous system (ANS) and hypothalamic pituitary adrenal-axis (HPA-axis), functions to maintain homeostasis in response to stressors. Cervical spine manual therapy has been shown to differentially modulate the stress response in healthy populations. No study has investigated whether cervical spine mobilizations can differentially modulate the stress response in individuals with persistent post-concussion symptoms (PPCS), a population characterized by a dysfunctional stress response.

METHODS

A randomized, controlled, parallel design trial was performed to investigate whether upper or lower cervical spine mobilization can differentially modulate components of the stress response in individuals with PPCS. The outcomes were salivary cortisol (sCOR) concentration (primary) and the HRV metric, rMSSD, measured with a smartphone application (secondary). Nineteen males diagnosed with PPCS, aged 19-35, were included. Participants were randomly assigned into either intervention group, upper (n = 10) or lower (n = 9) cervical spine mobilization. Each outcome was collected at different time points, pre- and post-intervention. Statistical analyses were performed using the Friedman's Two-Way ANOVA, Mann-Whitney U test, and Wilcoxon Signed Rank Test.

RESULTS

There was a statistically significant within-group reduction in sCOR concentration 30 minutes following lower cervical spine mobilizations and statistically significant within-group increase in rMSSD 30 minutes following upper cervical spine mobilizations.

CONCLUSION

The results of this trial provide preliminary evidence for cervical spine mobilizations to differentially modulate components of the stress response at specific time points. Understanding the mechanisms of the effect of cervical spine mobilizations on the stress response provides a novel rationale for selecting cervical spine mobilizations to rehabilitate individuals with PPCS.

Diurnal cortisol measures are distinctively associated with evaluation of neuroticism by self and others

The link between neuroticism and the various indicators of daily cortisol fluctuations is frequently noted to be inconsistent or lacking in strength. The current study aimed to investigate the predictive capacity of both self-assessment and external evaluations of neuroticism, along with their interaction, on multiple indices of diurnal cortisol variations. This research involved the assessment of neuroticism using self-report and external evaluations among 166 working individuals, coupled with the collection of saliva samples over two consecutive workdays. Employing multilevel response surface analysis, our findings indicated that self-reported neuroticism exhibited a stronger association with cortisol indices compared to external evaluations. Additionally, the level of alignment between self-assessment and external ratings of neuroticism specifically impacted the prediction of estimates of daily cortisol production. We discuss the theoretical and practical implications of these results.

Endogenous estrogen metabolites as oxidative stress mediators and endometrial cancer biomarkers

BACKGROUND

Endometrial cancer is the most common gynecologic malignancy found in developed countries. Because therapy can be curative at first, early detection and diagnosis are crucial for successful treatment. Early diagnosis allows patients to avoid radical therapies and offers conservative management options. There are currently no proven biomarkers that predict the risk of disease occurrence, enable early identification or support prognostic evaluation. Consequently, there is increasing interest in discovering sensitive and specific biomarkers for the detection of endometrial cancer using noninvasive approaches.

CONTENT

Hormonal imbalance caused by unopposed estrogen affects the expression of genes involved in cell proliferation and apoptosis, which can lead to uncontrolled cell growth and carcinogenesis. In addition, due to their ability to cause oxidative stress, estradiol metabolites have both carcinogenic and anticarcinogenic properties. Catechol estrogens are converted to reactive quinones, resulting in oxidative DNA damage that can initiate the carcinogenic process. The molecular anticancer mechanisms are still not fully understood, but it has been established that some estradiol metabolites generate reactive oxygen species and reactive nitrogen species, resulting in nitro-oxidative stress that causes cancer cell cycle arrest or cell death. Therefore, identifying biomarkers that reflect this hormonal imbalance and the presence of endometrial cancer in minimally invasive or noninvasive samples such as blood or urine could significantly improve early detection and treatment outcomes.

Heat inactivation of SARS-CoV 2 enabled the measurement of salivary cortisol during COVID-19 pandemic

BACKGROUND AND AIM

Salivary cortisol has become an essential tool in the management of cortisol-related disease. In 2020 the sudden outbreak of COVID-19 pandemic caused several concerns about the use of saliva, due to the risk of contamination, and a European consensus further discourage using salivary cortisol. To decrease infectious risk, we handled specimens by applying a heat treatment to inactivate viral particles, further evaluating the impact of the COVID-19 pandemic on the use of salivary cortisol in clinical practice.

MATERIAL AND METHODS

Saliva samples were exposed for 10 min at 70 °C, then cortisol was measured using LC-MS/MS. The number of salivary cortisol examinations from 2013 to 2022 was extracted from the local electronic database: those performed in 2019, 2020, and 2021 were analyzed and compared with the historical data.

RESULTS

During 2020 we observed a decrease of 408 (-20%) examinations (p = 0.05) compared to 2019; especially in salivary cortisol daily rhythm and salivary cortisol/cortisone ratio (respectively reduction of 47% and 88%, p = 0.003 and p = 0.001). Analyzing year 2021 compared with 2020 we reported an increase of 420 examinations (+20%, p = 0.01), with a complete recovery of salivary cortisol measurement (considering 2019: p = 0.71). Major differences were observed between morning salivary cortisol (-20%, p = 0.017), LNSC (-21%, p = 0.012) and salivary cortisol rhythm (-22%, p = 0.056). No Sars-Cov2 infections related to working exposure were reported among laboratory's employers.

CONCLUSIONS

We speculate that the adoption of an appropriate technique to inactivate viral particles in saliva specimens allowed the safety maintenance of salivary collections, also during the Sars-CoV-2 outbreak.

Effects of menstrual cycle phase and ovulation on the salivary cortisol awakening response

The cortisol awakening response (CAR) is influenced by several state and trait variables, one of which might be the menstrual cycle in women. Previous results suggested that the CAR is enhanced around ovulation, which is why it has been recommended to avoid sampling during the ovulatory phase. In two separate studies, we aimed to replicate previous findings that reported the CAR's modulation across the menstrual cycle, especially during ovulation. In Study 1, a group of 27 healthy naturally cycling women collected saliva at 0, 30, 45, and 60 min post-awakening on two days during their follicular, ovulatory, and luteal phases in a repeated measures design. In Study 2, CAR samples were collected from 30 healthy naturally cycling women on seven consecutive days around the expected ovulation. To increase reliability of CAR measurements, participants' compliance of saliva sampling times was monitored, ovarian steroids (estradiol and progesterone) were collected, and ovulation was confirmed with specific test kits. Contrary to our expectations, we detected no differences in the CAR over the menstrual cycle, and no significant association with variations in estradiol and progesterone. In addition, we excluded confounding effects such as compliance and validated the cycle phase. These results suggest that the CAR is largely robust against hormonal variations across the menstrual cycle, including the mid-cycle phase around ovulation. However, further research is needed to understand the potential ovarian steroid-induced modulation of HPA axis functioning and the menstrual cycle's effects on salivary cortisol levels in psychobiological studies.

Advances in Research on Pig Salivary Analytes: A Window to Reveal Pig Health and Physiological Status

Saliva is an important exocrine fluid that is easy to collect and is a complex mixture of proteins and other molecules from multiple sources from which considerable biological information can be mined. Pig saliva, as an easily available biological liquid rich in bioactive ingredients, is rich in nucleic acid analytes, such as eggs, enzymes, amino acids, sugars, etc. The expression levels of these components in different diseases have received extensive attention, and the analysis of specific proteins, metabolites, and biological compositions in pig saliva has become a new direction for disease diagnosis and treatment. The study of the changes in analytes in pig saliva can provide a new strategy for early diagnosis, prognosis assessment, and treatment of diseases. In this paper, the detection methods and research progress of porcine salivary analytes are reviewed, the application and research progress of porcine salivary analytes in diseases are discussed, and the future application prospect is presented.

Saliva Sampling Material Matters: Effects on the Results of Saliva Analysis in Pigs

The use of saliva as a biological sample from pigs is of high practical interest because blood collection from pigs is difficult and stressful. In this study, the influence of two different materials, a cotton roll and a polypropylene sponge, in porcine saliva collection was evaluated. For this purpose, the effect of the material used for sampling was evaluated in a panel of 13 analytes, including those related to stress (cortisol and oxytocin), inflammation and immunity (adenosine deaminase, haptoglobin and myeloperoxidase), redox homeostasis (the cupric reducing ability of saliva, the ferric reducing activity of saliva, and the Trolox equivalent antioxidant capacity), and sepsis (procalcitonin), as well as other routine analytes related to metabolism and different tissues and organs, such as lactate dehydrogenase, creatine kinase, urea, and total protein concentration. The polypropylene sponge provided a higher sample volume than the cotton roll. Although the results of some salivary analytes were equivalent for both materials, other analytes, such as creatine kinase, haptoglobin and total proteins, showed significant differences depending on the material used for saliva collection. Therefore, the type of material used for salivary collection in pigs should be considered when interpreting the results of analyses of the salivary analytes.

Autonomic nervous system and endocrine system response to upper and lower cervical spine mobilization in healthy male adults: a randomized crossover trial

BACKGROUND

Cervical spine mobilizations may differentially modulate both components of the stress response, consisting of the autonomic nervous system and hypothalamic pituitary adrenal-axis, depending on whether the target location is the upper or lower cervical spine. To date, no study has investigated this.

METHODS

A randomized, crossover trial investigated the effects of upper versus lower cervical mobilization on both components of the stress response simultaneously. The primary outcome was salivary cortisol (sCOR) concentration. The secondary outcome was heart rate variability measured with a smartphone application. Twenty healthy males, aged 21-35, were included. Participants were randomly assigned to block-AB (upper then lower cervical mobilization, n = 10) or block-BA (lower than upper cervical mobilization, n = 10), separated by a one-week washout period. All interventions were performed in the same room (University clinic) under controlled conditions. Statistical analyses were performed with a Friedman's Two-Way ANOVA and Wilcoxon Signed Rank Test.

RESULTS

Within groups, sCOR concentration reduced thirty-minutes following lower cervical mobilization (p = 0.049). Between groups, sCOR concentration was different at thirty-minutes following the intervention (p = 0.018).

CONCLUSION

There was a statistically significant reduction in sCOR concentration following lower cervical spine mobilization, and between-group difference, 30 min following the intervention. This indicates that mobilizations applied to separate target locations within the cervical spine can differentially modulate the stress response.

Daily cortisol variations are predicted proximally by self-efficacy beliefs at work and indirectly by perceived self-regulatory abilities in managing negative emotions

In the present ecological study, we analyzed the relations of a set of self-efficacy beliefs at work to parameters of diurnal cortisol variation. Specifically, using data collected during two consecutive working days from 166 workers, we tested a mediation model positing social and work-related self-efficacy beliefs as mediators of the relations between self-regulatory emotional self-efficacy beliefs in managing negative emotions and cortisol indicators. Results from the multilevel mediation analyses supported the proposed model for work-related self-efficacy, which resulted as a significant mediator of the relation between self-regulatory emotional self-efficacy beliefs in managing negative emotions and the overall cortisol daily production indexed by computing the area under the curve with respect to the ground. Findings suggest the importance of self-efficacy beliefs for workers' physiological adjustment. Theoretical and practical contributions of the findings are discussed.

Using LC-MS/MS to Determine Salivary Steroid Reference Intervals in a European Older Adult Population

A number of steroids, including glucocorticoids and sex hormones, have been associated with neurodegenerative and cardiovascular conditions common in aging populations. The application of liquid chromatography tandem mass spectrometry (LC-MS/MS) steroid analysis offers an opportunity to conduct simultaneous multiplex steroid analysis within a given sample. In this paper, we describe the application of an LC-MS/MS steroid analysis method for the assessment of reference ranges of steroids in human saliva samples (200 µL) collected from older adults (age 50 years and above) enrolled in a European cohort investigating the risk for Alzheimer's dementia. Saliva samples were prepared using supported liquid extraction (SLE) along with a calibration curve and analysed using a Waters I-Class UPLC (Ultra Performance Liquid Chromatography) and a Sciex QTrap 6500+ mass spectrometer. Mass spectrometry parameters of steroids were optimised for each steroid and a method for the chromatographic separation of 19 steroids was developed. Lower limits of quantitation (LLOQs), linearity and other method criteria were assessed. In total, data from 125 participants (500 samples) were analysed and assessed for reference ranges (64 male, 61 female). A total of 19 steroids were detected in saliva within the range of the method. There were clear diurnal patterns in most of the steroid hormones detected. Sex differences were observed for androstenedione (A4), testosterone (T), cortisone (E) and aldosterone (Aldo). In the first sample of the day, dehydroepiandrosterone (DHEA) was significantly higher in healthy volunteers compared to those with Alzheimer's disease biomarkers. This LC-MS/MS method is suitable for the analysis of 19 steroids in saliva in adults.

Evaluation of physiological stress in free-ranging bears: current knowledge and future directions

Stress responses, which are mediated by the neurogenic system (NS) and hypothalamic-pituitary-adrenal (HPA) axis help vertebrates maintain physiological homeostasis. Fight-or-flight responses are activated by the NS, which releases norepinephrine/noradrenaline and epinephrine/adrenaline in response to immediate stressors, whilst the HPA axis releases glucocorticoid hormones (e.g. cortisol and corticosterone) to help mitigate allostatic load. There have been many studies on stress responses of captive animals, but they are not truly reflective of typical ranges or the types of stressors encountered by free-ranging wildlife, such as responses and adaptation to environmental change, which are particularly important from a conservation perspective. As stress can influence the composition of age and sex classes of free-ranging populations both directly and indirectly, ecological research must be prioritised towards more vulnerable taxa. Generally, large predators tend to be particularly at risk of anthropogenically driven population declines because they exhibit reduced behavioural plasticity required to adapt to changing landscapes and exist in reduced geographic ranges, have small population sizes, low fecundity rates, large spatial requirements and occupy high trophic positions. As a keystone species with a long history of coexistence with humans in highly anthropogenic landscapes, there has been growing concern about how humans influence bear behaviour and physiology, via numerous short- and long-term stressors. In this review, we synthesise research on the stress response in free-ranging bear populations and evaluate the effectiveness and limitations of current methodology in measuring stress in bears to identify the most effective metrics for future research. Particularly, we integrate research that utilised haematological variables, cardiac monitors and Global Positioning System (GPS) collars, serum/plasma and faecal glucocorticoid concentrations, hair cortisol levels, and morphological metrics (primarily skulls) to investigate the stress response in ursids in both short- and long-term contexts. We found that in free-ranging bears, food availability and consumption have the greatest influence on individual stress, with mixed responses to anthropogenic influences. Effects of sex and age on stress are also mixed, likely attributable to inconsistent methods. We recommend that methodology across all stress indicators used in free-ranging bears should be standardised to improve interpretation of results and that a wider range of species should be incorporated in future studies.

Sex and pubertal influences on the neurodevelopmental underpinnings of schizophrenia: A case for longitudinal research on adolescents

Sex is a significant source of heterogeneity in schizophrenia, with more negative symptoms in males and more affective symptoms and internalizing comorbidity in females. In this narrative review, we argue that there are likely sex differences in the pathophysiological mechanisms of schizophrenia-spectrum disorders (SZ) that originate during puberty and relate to the sex-specific impacts of pubertal maturation on brain development. Pubertal maturation might also trigger underlying (genetic or other) vulnerabilities in at-risk individuals, influencing brain development trajectories that contribute to the emergence of SZ. This review is the first to integrate links between pubertal development and neural development with cognitive neuroscience research in SZ to form and evaluate these hypotheses, with a focus on the frontal-striatal and frontal-limbic networks and their hypothesized contribution to negative and mood symptoms respectively. To test these hypotheses, longitudinal research with human adolescents is needed that examines the role of sex and pubertal development using large cohorts or high risk samples. We provide recommendations for such studies, which will integrate the fields of psychiatry, developmental cognitive neuroscience, and developmental endocrinology towards a more nuanced understanding of the role of pubertal factors in the hypothesized sex-specific pathophysiological mechanisms of schizophrenia.

Qualitative and Quantitative Mass Spectrometry in Salivary Metabolomics and Proteomics

The metabolomics and proteomics analysis of saliva, an excellent biofluid that is a rich source of biological compounds, allows for the safe and frequent screening of drugs, their metabolites, and molecular biomarkers of various diseases. One of the most frequently used analytical methods in saliva analysis is liquid chromatography coupled with mass spectrometry (LC-MS) and tandem mass spectrometry. The low ionisation efficiency of some compounds and a complex matrix makes their identification by MS difficult. Furthermore, quantitative analysis by LC-MS frequently cannot be performed without isotopically labelled standards, which usually have to be specially synthesised. This review presented reports on qualitative and quantitative approaches in salivary metabolomics and proteomics. The purpose of this manuscript was to present the challenges, advances, and future prospects of mass spectrometry, both in the analysis of salivary metabolites and proteins. The presented review should appeal to those interested in the recent advances and trends in qualitative and quantitative mass spectrometry in salivary metabolomics and proteomics, which may facilitate a diagnostic accuracy, the evaluation of treatment efficacy, the early diagnosis of disease, and a forensic investigation of some unapproved drugs for any medical or dietary administration.

The association of self-esteem variability with diurnal cortisol patterns in a sample of adult workers

This study explored the relationships between self-esteem level and self-esteem variability at work with parameters of diurnal cortisol rhythm, using intensive longitudinal data collected during two consecutive working days from N = 166 workers. Participants self-reported measures of sex, height, weight, self-esteem, neuroticism, and negative events at T0. Then, they answered a single item of self-esteem 4 times per day. Self-esteem variability was assessed by means of the relative variability index approach proposed by Mestdagh et al. (2018). Further, participants collected salivary samples at specific time points for analysis of diurnal cortisol patterns. Self-esteem average levels and a specific form of self-esteem variability were associated with diurnal cortisol parameters. In particular, results showed a relationship between low self-esteem and blunted cortisol awakening response, specifically when low self-esteem levels were stable over time. Moreover, self-esteem variability predicted a lower diurnal cortisol decline and a smaller magnitude of overall cortisol production. Present findings highlight the neuroendocrine correlates of self-esteem level and variation at work, suggesting potential pathways by which short-term variability in self-esteem states may impact hypothalamic-pituitary-adrenal axis functioning and long-term workers' health and well-being.

Underlying mechanisms in the relationship between stress and alcohol consumption in regular and risky drinkers (MESA): methods and design of a randomized laboratory study

Background

Excessive alcohol consumption and alcohol use disorders (AUD) are among the leading preventable causes of premature morbidity and mortality and are considered a major public health concern. In order to reduce the individual and societal burden of excessive alcohol use, it is crucial to identify high-risk individuals at earlier stages and to provide effective interventions to prevent further progression. Stressful experiences are important risk factors for excessive alcohol consumption and AUDs. However, the underlying biological and psychological mechanisms are still poorly understood.

Methods

The project “Underlying mechanisms in the relationship between stress and alcohol consumption in regular and risky drinkers (MESA)” is a randomized controlled study that started in December 2018 and is conducted in a laboratory setting, which aims to identify moderators and mediators of the relationship between acute stress and alcohol consumption among regular and risky drinkers. Regular and risky drinkers are randomly assigned to a stress induction or a control condition. Several processes that may mediate (emotional distress, endocrine and autonomic stress reactivity, impulsivity, inhibitory control, motivational sensitization) or moderate (trait impulsivity, childhood maltreatment, basal HPA-axis activity) the relation between stress and alcohol consumption are investigated. As primary dependent variable, the motivation to consume alcohol following psychosocial stress is measured.

Discussion

The results of this study could help to provide valuable targets for future research on tailored interventions to prevent stress-related alcohol consumption.

A System-on-Board Integrated Multi-analyte PoC Biosensor for Combined Analysis of Saliva and Exhaled Breath

The need for oral health monitoring Point of Care (PoC) systems is ever growing. This is effectively highlighted by the ongoing COVID-19 pandemic where the lack of rapid PoC testing has placed an unsustainable burden on centralized laboratory testing. Urgent development has furthered pathogenic nucleic acid and antibody detection in oral samples throat swabs, but without corresponding advancements in biochemical monitoring through oral biosensing. We have recently reported two novel biosensor technologies for detection of high impact hormones: cortisol in saliva by organic electrolyte gated FETs (OEGFETs), and 8-isoprostane in exhaled breath condensate (EBC) using molecularly imprinted electroimpedance spectroscopy biosensors (MIP EIS). In this work, we report a first stage integration of the two biosensors - previously bench-top proven - with a miniaturized semi-hermetically sealed soft-fluidic enclosure, onto a low-power (<300 mW) customized printed circuit board. Our findings established comparable detection thresholds for the miniaturized board-based configuration and a lab-based test setup, and their ability to characterize, calibrate, and operate these small footprint biosensors. Testing with the 8-isoprostane EBC MIP EIS biosensors showed the system-on-board had an effective frequency range of 100-100kHz, comparable to lab bench impedance analyzers. Despite internal impedance increases of 210%, the expected data features are present in the impedance graphs collected with the PCB. The system-on-board experiments using OEGFET aptasensor showed a predictable behavior and comparable sensor detection range and resolution using unadulterated supernatant and serial dilutions of cortisol over a range of 273 μM to 2.73pM. The portable, multi-analyte oral biosensor is a promising prototype for future packaging and clinical validation.

Simultaneous quantitative analysis of seven steroid hormones in human saliva: A novel method based on O-ethylhydroxylamine hydrochloride as derivatization reagent

RATIONALE

Saliva has been widely accepted as a more convenient alternative to serum or plasma in the field of clinical diagnosis. However, the detection of trace components in saliva has been a bottleneck problem. The aim of this work was to develop a highly sensitive and reliable method for simultaneously determining the trace steroid hormones including some with poor ionization efficiency in human saliva by liquid chromatography/tandem mass spectrometry (LC/MS).

METHODS

Saliva was deproteinated by acetonitrile containing mixed isotope internal standards and extracted with methyl tert-butyl ether. The extraction solution was dried under a stream of nitrogen and the residue was derivatized using 50 mM O-ethylhydroxylamine hydrochloride in 80% methanol/water solution (v/v). The processed sample was determined by LC/MS in multiple reaction monitoring (MRM) mode.

RESULTS

The method was successfully established for the simultaneous quantification of seven steroid hormones in human saliva and showed excellent specificity and sensitivity. The limits of quantification (LOQs) of all steroid hormones were below 5 pg/mL, in particular, the LOQ of progesterone was as low as 0.15 pg/mL. The linear correlation coefficients (r) were greater than 0.9990 in the range of 2-200 pg/mL for T, DHEA, A4, P4, P5, and 17OHP4 and in the range of 5-500 pg/mL for 17OHP5. The intra-day and inter-day variability ranged from 1.86% to 7.83% and 1.95% to 10.4%, respectively. The recovery of the method ranged from 86.9% to 111.1% for all steroid hormones using three spiked concentrations.

CONCLUSIONS

A novel LC/MS/MS method was developed for the simultaneous quantification of seven kinds of trace steroid hormones in human saliva. The results of the methodological study showed that the method exhibited excellent sensitivity and reliability for the evaluation of free steroid hormones in the human body. It is believed that this method could provide useful information of steroid hormone metabolism for auxiliary diagnosis of some endocrine disorders.

Basics for the potential use of saliva to evaluate stress, inflammation, immune system, and redox homeostasis in pigs

The use of saliva as a biological sample has many advantages, being especially relevant in pigs where the blood collection is highly stressful and painful, both for the animal and the staff in charge of the sampling. Currently one of the main uses of saliva is for diagnosis and detection of infectious diseases, but the saliva can also be used to measure biomarkers that can provide information of stress, inflammation, immune response and redox homeostasis. This review will be focused on the analytes that can be used for such evaluations. Emphasis will be given in providing data of practical use about their physiological basis, how they can be measured, and their interpretation. In addition, some general rules regarding sampling and saliva storage are provided and the concept of sialochemistry will be addressed. There is still a need for more data and knowledge for most of these biomarkers to optimize their use, application, and interpretation. However, this review provides updated data to illustrate that besides the detection of pathogens in saliva, additional interesting applicative information regarding pigs´ welfare and health can be obtained from this fluid. Information that can potentially be applied to other animal species as well as to humans.

The markers of stress in swine oral fluid

Introduction

The study measured the hormonal and protein markers of acute stress, those of oxidative stress and total antioxidant capacity (TAC) in swine oral fluid, determined which of these parameters would be the most appropriate for future livestock welfare assessment and established the time when the samples should be taken.

Material and Methods

Stress was induced in 7 out of 14 castrated six-week-old Danbred×Duroc pigs by immobilisation on a nasal snare at 8 a.m., 1 p.m., and 6 p.m. and samples were taken both directly after the stressor was applied and 30 min later. The remaining pigs were the control group, which were not immobilised; their samples were taken at the same times. The concentrations of hormones and malondialdehyde (MDA) were measured using liquid chromatography with tandem mass spectrometry, while those of alpha-amylase and TAC were measured using spectrophotometry.

Results

The levels of cortisol and cortisone increased with statistical significance immediately after the acute stress response and 30 min later. A cut-off value set at 0.25 ng/mL cortisol concentration was capable of distinguishing between the stressed and control groups with 100% accuracy in evening samples and 95% accuracy overall. Prednisolone was not present, and the levels of testosterone and corticosterone were low and not distinctive. Alpha-amylase became significantly more concentrated during stress induction and 30 min later. The TAC and MDA levels rose after the stress but without statistical significance.

Conclusion

The most suitable markers of acute stress were cortisol, cortisone and alpha-amylase. Oral fluid is a reliable material for monitoring the level of pigs’ stress and should be collected in the evening.

Salivary ghrelin response to drinks varying in protein content and quantity and association with energy intake and appetite

Salivary hormone analysis is a non-invasive alternative to blood-borne hormone analysis. The orexigenic hormone ghrelin has been detected in human saliva, though the relationship between salivary and blood-borne ghrelin and salivary ghrelin's association with energy intake (EI) and appetite remains unclear. The primary aim of this study was to compare salivary and plasma ghrelin responses to dairy breakfast drinks varying in protein content and quantity, and to determine the relationship between salivary ghrelin and EI and appetite. Participants (n = 25) consumed four test drinks, varying in protein content and quantity, on four separate days in a double-blind randomized controlled study. Salivary and plasma total ghrelin were measured at 0, 30, 60 and 120 min and appetite perceptions at 0, 30, 60, 90 and 120 min. A buffet-style test meal was presented at 120 min to measure ad libitum EI. There was no correlation between the sample means for fasted salivary and plasma ghrelin (r = 0.099, p = 0.637). Furthermore, there was no within-participant association between fasted salivary and plasma ghrelin (r = -0.041, p = 0.725). Mean bias between fasted salivary and plasma ghrelin was -448 pg/ml (95% confidence intervals (CI) = -623 - -273 pg/ml) and upper and lower limits of agreement (LOA) were 427 pg/ml and -1324 pg/ml, respectively. Variation in postprandial levels of salivary and plasma ghrelin within-participants were not associated (r = -0.004, p = 0.943). There was no significant association between EI and salivary (r = 0.003, p = 0.979) or plasma (r = -0.080, p = 0.492) ghrelin. Salivary ghrelin was not significantly correlated with composite appetite score (r = 0.023; p = 0.654), though plasma ghrelin was (r = 0.225, p < 0.001). Mean bias between postprandial salivary and plasma ghrelin was -210 pg/ml (95% CI = -380 - -40 pg/ml) and upper and lower LOA were 641 pg/ml and -1061 pg/ml, respectively. These findings suggest that salivary and plasma ghrelin responses to drinks varying in protein content and quantity are unrelated and that salivary ghrelin is not associated with EI or appetite perceptions in healthy non-obese adults. This trial was registered at www.clinicaltrial.gov (NCT01597024).

Comparative analysis of the effects of collection methods on salivary steroids

BACKGROUND

Steroid hormone test for saliva was a promising area of research, however the impact of different collection methods on salivary steroids was underexplored so far. This study was designed to compare the effects of different collection methods (unstimulated or stimulated by chewing paraffin, forepart or midstream) on salivary flow rate, concentrations and secretion rates of steroids in saliva.

METHODS

Whole-saliva samples were collected from 10 systemically and orally healthy participants, whose forepart and midstream segments of saliva were collected under unstimulated and stimulated conditions, with the salivary flow rate of each sample recorded. The concentrations and secretion rates of salivary steroids including testosterone, dehydroepiandrosterone (DHEA) and progesterone were measured by ELISA, with the multiple of change calculated.

RESULTS

The results indicated mechanical stimulation used in collection of saliva samples could affect concentrations and secretion rates of steroids, whereas forepart and midstream segments had little differences in levels of salivary steroids, which effects could be partly influenced by individual specificity. The asynchronism in change of secretion rate of steroids with that of salivary flow rate might play an important role during this course.

CONCLUSION

Based on these findings, we suggested to use the same collection method throughout one analytical study on salivary steroids or in longitudinal observations to ensure the comparability of the saliva samples collected.

Cimetidine-induced androgenic failure causes cell death and changes in actin, EGF and V-ATPase immunoexpression in rat submandibular glands

Submandibular gland (SMG) is responsive to androgens via androgen receptor (AR). We verified whether cimetidine induces androgenic dysfunction in SMG, and evaluated the structural integrity, cell death and immunoexpression of actin, EGF and V-ATPase in androgen-deficient SMG. Male rats received cimetidine (CMTG) and control animals (CG) received saline. Granular convoluted tubules (GCTs) diameter and number of acinar cell nuclei were evaluated. TUNEL and immunofluorescence reactions for detection of AR, testosterone, actin, EGF and V-ATPase were quantitatively analysed. In CG, testosterone immunolabelling was detected in acinar and ductal cells cytoplasm. AR-immunolabelled nuclei were observed in acinar cells whereas ductal cells showed AR-immunostained cytoplasm, indicating a non-genomic AR action. In CMTG, the weak testosterone and AR immunoexpression confirmed cimetidine-induced androgenic failure. A high cell death index was correlated with decreased number of acinar cells, GCTs diameter and EGF immunoexpression under androgenic dysfunction. Actin immunofluorescence decreased in the SMG cells, but an increased and diffuse cytoplasmic V-ATPase immunolabelling was observed in striated ducts, suggesting a disruption in the actin-dependent V-ATPase recycling due to androgenic failure. Our findings reinforce the androgenic role in the maintenance of SMG histophysiology, and point to a potential clinical use of cimetidine against androgen-dependent glandular tumour cells.

Monitoring Salivary Levels of Interleukin 1 Beta (IL-1β) and Vascular Endothelial Growth Factor (VEGF) for Two Years of Orthodontic Treatment: A Prospective Pilot Study

Results

A gradual increase in IL-1β and VEGF was observed at alignment, reaching significance at space closure (p = 0.002 and p = 0.025, respectively). At finishing, both IL-1β and VEGF declined, however, without reverting to baseline values (p = 0.172 and p = 0.207, respectively). Bland-Altman analysis showed the agreement between IL-1β and VEGF in terms of a systematic increase, with a higher percentage difference for VEGF.

Conclusions

The salivary levels of both IL-1β and VEGF increased following orthodontic treatment and reached their peaks during the treatment stage of space closure. This novel approach provides a hint on how and when to sample saliva during orthodontic treatment to analyse bone remodelling.

Estradiol and progesterone as resilience markers? - Findings from the Swiss Perimenopause Study

While resilience seems to be associated with a variety of biological markers, studies assessing such correlates in women during the perimenopause are lacking. The perimenopause constitutes a phase of major biopsychosocial changes, during which the sex hormones estradiol (E2) and progesterone (P4) eventually decrease significantly. The aim of this study was to examine the extent to which the declining levels of E2 and P4 serve as resilience markers in perimenopausal women. In 129 healthy perimenopausal women aged 40-56 years, saliva samples were collected on every fourth day over a period of four weeks in order to investigate E2 and P4 levels. All participants completed psychosocial questionnaires including variables related to resilience, well-being, and mental health. Perimenopausal status was determined using the Stages of Reproductive Aging Workshop (STRAW) criteria. The results indicate that P4 is linked to psychosocial resilience. More precisely, women with higher P4 levels seem to be more resilient than women with lower P4 levels, irrespective of the perimenopausal status. No such relation was found for E2 levels. Further analyses revealed that women with higher P4 levels experience significantly higher life satisfaction, lower perceived stress, and lower depressive symptoms than women with lower P4 levels. Accordingly, P4 can be considered as a biological marker of resilience in perimenopause.

Time-restricted eating and concurrent exercise training reduces fat mass and increases lean mass in overweight and obese adults

The purpose of this study was to determine whether time-restricted eating (TRE), also known as time-restricted feeding, was an effective dietary strategy for reducing fat mass and preserving fat-free mass while evaluating changes in cardiometabolic biomarkers, hormones, muscle performance, energy intake, and macronutrient intake after aerobic and resistance exercise training in physically inactive and overweight or obese adults. This study was a randomized, controlled trial. Overweight and obese adults (mean ± SD; age: 44 ± 7 years; body mass index [BMI]: 29.6 ± 2.6 kg/m2 ; female: 85.7%) were randomly assigned to a TRE or normal eating (NE) dietary strategy group. The TRE participants consumed all calories between 12:00 p.m. and 8:00 p.m., whereas NE participants maintained their dietary habits. Both groups completed 8 weeks of aerobic exercise and supervised resistance training. Body composition, muscle performance, energy intake, macronutrient intake, physical activity, and physiological variables were assessed. A total of 21 participants completed the study (NE: n = 10; TRE: n = 11). A mild energy restriction was observed for TRE (~300 kcal/day, 14.5%) and NE (~250 kcal/day, 11.4%). Losses of total body mass were significantly greater for TRE (3.3%) relative to NE (0.2%) pre- to post-intervention, of which TRE had significantly greater losses of fat mass (9.0%) compared to NE (3.3%). Lean mass increased during the intervention for both TRE (0.6%) and NE (1.9%), with no group differences. These data support the use of TRE and concurrent exercise training as a short-term dietary strategy for reducing fat mass and increasing lean mass in overweight and obese adults.

Biological Markers in Anxiety Disorders

Anxiety disorders are one of the most commonly reported disorders in psychiatry, causing a high medical and socio-economic burden. Recently, there has been a soaring interest in the biological basis of anxiety disorders, which is reflected in an increasing number of articles related to the topic. Due to the ambiguity of the diagnosis and a large number of underdiagnosed patients, researchers are looking for laboratory tests that could facilitate the diagnosis of anxiety disorders in clinical practice and would allow for the earliest possible implementation of appropriate treatment. Such potential biomarkers may also be useable in monitoring the efficacy of pharmacological therapy for anxiety disorders. Therefore this article reviews the literature of potential biomarkers such as components of saliva, peripheral blood, cerebrospinal fluid (CSF), and neuroimaging studies. There are promising publications in the literature that can be useful. The most valuable and promising markers of saliva are cortisol, lysozyme, and α-amylase (sAA). In the blood, in turn, we can distinguish serotonin, brain-derived serum neurotrophic factor (BDNF), cortisol, and microRNA. Structural changes in the amygdala and hippocampus are promising neuroimaging markers, while in CSF, potential markers include oxytocin and 5-Hydroxyindoleacetic acid (5-HIAA). Unfortunately, research in the field of biomarkers is hampered by insufficient knowledge about the etiopathogenesis of anxiety disorders, the significant heterogeneity of anxiety disorders, frequent comorbidities, and low specificity of biomarkers. The development of appropriate biomarker panels and their assessment using new approaches may have the prospective to overcome the above-mentioned obstacles.

Analytical Methods for the Determination of Neuroactive Steroids

Neuroactive steroids are a family of all steroid-based compounds, of both natural and synthetic origin, which can affect the nervous system functions. Their biosynthesis occurs directly in the nervous system (so-called neurosteroids) or in peripheral endocrine tissues (hormonal steroids). Steroid hormone levels may fluctuate due to physiological changes during life and various pathological conditions affecting individuals. A deeper understanding of neuroactive steroids' production, in addition to reliable monitoring of their levels in various biological matrices, may be useful in the prevention, diagnosis, monitoring, and treatment of some neurodegenerative and psychiatric diseases. The aim of this review is to highlight the most relevant methods currently available for analysis of neuroactive steroids, with an emphasis on immunoanalytical methods and gas, or liquid chromatography combined with mass spectrometry.

Salivary Biomarkers of Stress, Anxiety and Depression

Stress, anxiety and depressive disorders are often characterized by the activation of the stress axis, which results in similar symptoms at some point in these disorders. These disorders are closely related to each other—they occur simultaneously or follow one another. The diagnosis of stress, anxiety and depression is not a perfect procedure currently—it is based on patient observation and an interview with the patient and their family. There are no laboratory tests that would dispel the doubts of the doctor making the diagnosis and allow the appropriate treatment to be implemented as soon as possible. Therefore, this study will review the components of saliva that could be helpful in the quick diagnosis of stress, anxiety and/or depression. Such potential salivary biomarkers could also be useful in monitoring the effectiveness of pharmacological treatment prescribed by a psychiatrist. The following are promising salivary biomarkers of stress, anxiety or depression: cortisol, immunoglobulin A (sIgA), lysozyme, melatonin, α-amylase (sAA), chromogranin A (CgA) and fibroblast growth factor 2 (FGF-2). To the best valuable potential salivary markers of stress, we can include cortisol, lysozyme, sAA and CgA. To differentiate depression from stress, salivary cortisol and melatonin can be helpful. Fluctuations in the concentrations of the above-mentioned substances in saliva indicate a particularly strong relationship with typical human psychological problems, such as stress, depression or anxiety.

Steroidome and metabolome analysis in gilt saliva to identify potential biomarkers of boar effect receptivity

Optimal management of gilt reproduction requires oestrus synchronization. Hormonal treatments are used for this purpose, but there is a growing demand for non-hormonal alternatives, especially in organic farms. The boar effect is an important alternative opportunity to induce and synchronize oestrus without hormones. Before puberty, gilts exhibit a 'waiting period' during which boar exposure could induce and synchronize the first ovulation. We searched for salivary biomarkers of this period of boar effect receptivity to improve detection of the gilts to stimulate with the perspective of enhancing the efficacy of the boar effect. Saliva samples were collected from 30 Large-White×Landrace crossbred gilts between 140 and 175 days of age. Gilts were exposed twice a day to a boar and subjected to oestrus detection from 150 to 175 days of age. Among the 30 gilts, 10 were detected in oestrus 4 to 7 days after the first introduction of the boar and were considered receptive to the boar effect, 14 were detected in oestrus more than 8 days after first boar contact, and six did not show oestrus and were considered non-receptive. Saliva samples from six receptive and six non-receptive gilts were analyzed for steroidome and for metabolome using gas chromatography coupled to tandem mass spectrometry and ¹H nuclear magnetic resonance spectroscopy, respectively. Four saliva samples per gilt were analyzed: 25 days and 11 days before boar introduction, the day of boar introduction, 3 days later for receptive gilts or 7 days later for non-receptive gilts. Twenty-nine steroids and 31 metabolites were detected in gilt saliva. Salivary concentrations of six steroids and three metabolites were significantly different between receptive and non-receptive gilts: progesterone and glycolate 25 days before boar introduction, 3α5β20α- and 3β5α20β-hexahydroprogesterone, dehydroepiandrosterone, androstenediol, succinate, and butyrate 11 days before boar introduction, and 3β5α-tetrahydroprogesterone on the day of boar introduction. Thus, nine potential salivary biomarkers of boar effect receptivity were identified in our experimental conditions. Further studies with higher numbers of gilts and salivary sampling points are necessary to ascertain their reliability.

Salivary and plasmatic oxytocin are not reliable trait markers of the physiology of the oxytocin system in humans

Single measurements of salivary and plasmatic oxytocin are used as indicators of the physiology of the oxytocin system. However, questions remain about whether they are sufficiently stable to provide valid trait markers of the physiology of the oxytocin system, and whether salivary oxytocin can accurately index its plasmatic concentrations. Using radioimmunoassay, we measured baseline plasmatic and/or salivary oxytocin from two independent datasets. We also administered exogenous oxytocin intravenously and intranasally in a triple dummy, within-subject, placebo-controlled design and compared baseline levels and the effects of routes of administration. Our findings question the use of single measurements of baseline oxytocin concentrations in saliva and plasma as valid trait markers of the physiology of the oxytocin system in humans. Salivary oxytocin is a weak surrogate for plasmatic oxytocin. The increases in salivary oxytocin observed after intranasal oxytocin most likely reflect unabsorbed peptide and should not be used to predict treatment effects.

Human Stress Detection: Cortisol Levels in Stressed Speakers Predict Voice-Based Judgments of Stress

Despite recent evidence of a positive relationship between cortisol levels and voice pitch in stressed speakers, the extent to which human listeners can reliably judge stress from the voice remains unknown. Here, we tested whether voice-based judgments of stress co-vary with the free cortisol levels and vocal parameters of speakers recorded in a real-life stressful situation (oral examination) and baseline (2 weeks prior). Hormone and acoustic analyses indicated elevated salivary cortisol levels and corresponding changes in voice pitch, vocal tract resonances (formants), and speed of speech during stress. In turn, listeners' stress ratings correlated significantly with speakers' cortisol levels. Higher pitched voices were consistently perceived as more stressed; however, the influence of formant frequencies, vocal perturbation and noise parameters on stress ratings varied across contexts, suggesting that listeners utilize different strategies when assessing calm versus stressed speech. These results indicate that nonverbal vocal cues can convey honest information about a speaker's underlying physiological level of stress that listeners can, to some extent, detect and utilize, while underscoring the necessity to control for individual differences in the biological stress response.

Cranial osteopathic treatment and stress-related effects on autonomic nervous system measured by salivary markers: A pilot study

BACKGROUND

Variations in the concentration of salivary alpha amylase (sAA) may indicate a change in the autonomic nervous system functionality. In osteopathic medicine it has long been stated that the osteopathic manipulative treatment (OMT) can modulate the autonomic nervous system. Studies carried out on the compression of the fourth ventricle (CV4) have shown a positive effect in reducing the sympathetic tone. The goal of this pilot study is measuring the physiological response of the sAA levels after CV4 technique.

METHODS

90 subjects were randomly assigned to a sham, a control or a CV4 group. Randomization accounted for sex and score in the STAI-2 (form Y) questionnaire. Each subject completed the STAI-1 (form Y) questionnaire to evaluate the anxiety of the moment. sAA activity and saliva flow rate were measured. Saliva was collected before, immediately after and 30 min after treatment.

RESULTS

Within group analysis revealed that sAA activity increased significantly immediately after the technique application only in the CV4 group (p = 0,05). Between groups analysis show a significant difference of the sAA activity in the CV4 group respect the control group (p < 0,05), but no significant difference between CV4 and sham group (p > 0,05). The effect in the CV4 group after the intervention is highly variable and appeared to be related to the level of stress measured with the STAI-Y1 questionnaire (p = 0,002).

CONCLUSIONS

This study shows a positive effect of the CV4 procedure on sAA activity even if not significantly different from the sham procedure, probably due to the confounding effect of stress variability between groups.

A multi-centre international study of salivary hormone oestradiol and progesterone measurements in ART monitoring

RESEARCH QUESTION

Ovarian stimulation during IVF cycles involves close monitoring of oestradiol, progesterone and ultrasound measurements of follicle growth. In contrast to blood draws, sampling saliva is less invasive. Here, a blind validation is presented of a novel saliva-based oestradiol and progesterone assay carried out in samples collected in independent IVF clinics.

DESIGN

Concurrent serum and saliva samples were collected from 324 patients at six large independent IVF laboratories. Saliva samples were frozen and run blinded. A further 18 patients had samples collected more frequently around the time of HCG trigger. Saliva samples were analysed using an immunoassay developed with Salimetrics LLC.

RESULTS

In total, 652 pairs of saliva and serum oestradiol were evaluated, with correlation coefficients ranging from 0.68 to 0.91. In the European clinics, a further 237 of saliva and serum progesterone samples were evaluated; however, the correlations were generally poorer, ranging from -0.02 to 0.22. In the patients collected more frequently, five out of 18 patients (27.8%) showed an immediate decrease in oestradiol after trigger. When progesterone samples were assessed after trigger, eight out of 18 (44.4%) showed a continued rise.

CONCLUSIONS

Salivary oestradiol hormone testing correlates well to serum-based assessment, whereas progesterone values, around the time of trigger, are not consistent from patient to patient.

Field methods and strategies for assessing female reproductive functioning

A detailed understanding of female reproductive functioning is important to many disciplines including anthropology, evolutionary theory, demography, psychology, and biomedicine. In this article, I describe strategies and methods that have been used successfully in community-based studies of human reproduction, many in remote locales, to produce high quality biomarker data. These techniques are applicable to a wide range of research questions and populations, and to persons from adolescence through senescence. I give particular attention to the inherent challenges imposed by the cyclical and somewhat unpredictable nature of the hypothalamic-pituitary-ovarian axis including the necessity and difficulty of ascertaining the timing and occurrence of ovulation, the limits of different sampling regimes for capturing fluctuations in reproductive hormones, and the critical importance of recognizing and, when possible, reducing selection bias. I discuss the relative advantages and disadvantages of collecting saliva, urine, and dried blood spots, and describe some of the subtleties involved in collecting contamination-free samples. Once samples are collected, they must be stored in a manner that minimizes degradation; I describe techniques to keep samples cold even without access to electricity or dry ice. I also discuss various issues that should be considered during initial discussions with a laboratory and when samples are assayed by the laboratory. I include examples of techniques that have worked well in actual field studies, and examples of flawed analytical approaches that should be avoided. With these and other tools, even under technology-sparse conditions, researchers can investigate variability in human physiology across the breadth of human habitats.

Stimulated Salivary Cortisol as a Noninvasive Diagnostic Tool for Adrenal Insufficiency

BACKGROUND

Salivary cortisol is routinely used as a diagnostic test for Cushing syndrome. The diagnostic use of salivary cortisol for adrenal insufficiency (AI), however, is less established. We aimed to investigate the utility of morning basal and adrenocorticotropic hormone-stimulated salivary cortisol in diagnosing AI in Korean adults.

METHODS

We prospectively included 120 subjects (female, n=70) from Seoul National University Hospital. AI was defined as a stimulated serum cortisol level of &lt;496.8 nmol/L during the short Synacthen test (SST). Serum and saliva samples were drawn between 8:00 AM and 10:00 AM. Salivary cortisol levels were measured using an enzyme immunoassay kit.

RESULTS

Thirty-four patients were diagnosed with AI according to the SST results. Age, sex, body mass index, serum albumin levels, and serum creatinine levels did not significantly differ between the normal and AI groups. Basal and stimulated salivary cortisol levels were positively correlated with basal (r=0.538) and stimulated serum cortisol levels (r=0.750), respectively (all P&lt;0.001). Receiver operating characteristic curve analysis yielded a cutoff level of morning basal salivary cortisol of 3.2 nmol/L (sensitivity, 84.9%; specificity, 73.5%; area under the curve [AUC]=0.822). The optimal cutoff value of stimulated salivary cortisol was 13.2 nmol/L (sensitivity, 90.7%; specificity, 94.1%; AUC=0.959). Subjects with a stimulated salivary cortisol level above 13.2 nmol/L but a stimulated serum cortisol level below 496.8 nmol/L (n=2) had lower serum albumin levels than those showing a concordant response.

CONCLUSION

The diagnostic performance of stimulated salivary cortisol measurements after the SST was comparable to serum cortisol measurements for diagnosing AI.

Ejaculate Collection Influences the Salivary Oxytocin Concentrations in Breeding Male Pigs

Simple Summary

This study aimed to evaluate how the process of ejaculate collection affects oxytocin concentrations in saliva of boars used in artificial insemination. Saliva samples of 33 boars were collected the day before ejaculate collection, during the ejaculation time, and two hours after ejaculate collection. Free oxytocin and oxytocin linked to proteins were quantified in these saliva samples. Oxytocin concentrations during the ejaculation time were higher than the day before with oxytocin linked to proteins showing higher differences. In addition, younger boars, boars with higher libido intensity and boars of the Pietrain breed showed higher values of oxytocin in saliva during ejaculation than the day before. This study demonstrated that ejaculation influences the salivary oxytocin concentrations boars.

Abstract

The objective of the present study was to evaluate the possible changes of oxytocin concentrations in saliva during and after ejaculate collection in breeding boars usually used in artificial insemination programs. Saliva samples of 33 boars were collected the day before ejaculate collection (DB), during the ejaculation time (T0) and two hours after ejaculate collection (T2). Free oxytocin and oxytocin linked to proteins concentrations were measured by two methods previously developed and validated for saliva of pigs. Younger boars, boars with higher libido intensity and boars of the Pietrain breed showed higher values of oxytocin in saliva during ejaculation than the day before. In addition, boars with higher libido showed higher concentrations two hours after ejaculate collection than during the day before. These changes were of higher magnitude and significance when oxytocin linked to proteins was measured. In conclusion, this study demonstrated for the first time that ejaculation influences the salivary oxytocin concentrations in breeding boars, although this influence varies according to age, libido and breed.

Biochemical analysis of oral fluids for disease detection

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

Salivary cortisol as a marker of acute stress in dogs: a review

Public interest in the welfare of domestic dogs has increased in recent years. Dogs under human care should experience as little stress as possible, and as such it is necessary to measure and quantify their levels of stress. Stress parameters that can be measured noninvasively may help to identify the poor welfare of animals. This review aimed to determine whether and under what conditions the hormone cortisol in dog saliva can be used as a noninvasive acute stress marker. The use of salivary cortisol as a stress marker has some disadvantages, which can lead to data misinterpretations. A key factor is the standardized method of sampling and subsequent processing before analysis. In addition, possible circadian alternation and individual variability of cortisol hormone levels should be consistently considered during the preparation of the experimental scheme, statistical data processing and final interpretation of the results. Because of the complex nature of the stress response, the observation of salivary cortisol should be supplemented with behavioral observations, but it should be noted that behavioral stress symptoms may not always be positively correlated with stress hormone production. Besides behavioral observations, it is advisable to supplement the measurement of cortisol by other salivary stress markers of sympathetic-adrenal-medullary and hypothalamic-pituitary-adrenal pathways. This comprehensive assessment of the stress impact on the individual will enable one to characterize the level and type of stress.

Screening and identification of salivary biomarkers for assessing the effects of exogenous testosterone administration on HPG and HPA axes and ECS

The contents of steroids and endocannabinoids along with the ratios between them would be candidate biomarkers for sensitively and comprehensively assessing the role of testosterone in regulating the activities of the hypothalamus-pituitary-gonadal (HPG) axis, the hypothalamus-pituitaryadrenal (HPA) axis and endogenous cannabinoid system (ECS). However, previous studies mostly used the contents rather than the ratios as biomarkers. This study aimed to systematically screen and identify sensitive biomarkers from 21 candidates including both the contents of nine steroids and one endocannabinoid and their ratios in saliva. Three screening criteria were whether there were intergroup differences, time-dependent changes and considerable relative stability during a 4-h period after exogenous testosterone administration. This study used LC-APCI⁺-MS/MS to determine the salivary levels of the candidate biomarkers on 62 male healthy undergraduates who were divided into testosterone administration and placebo control groups. The results revealed that salivary testosterone, androstenedione, DHEA and the ratios of testosterone to estradiol and AEA, and of cortisol to testosterone and DHEA were sensitive biomarkers for assessing the effects of testosterone administration on the three neuroendocrine systems because they all showed significant intergroup differences and time-dependent changes and good relative stability. Salivary cortisol, cortisone and the ratios of testosterone to androstenedione and DHEA and of androstenedione to estrone, and of cortisol to cortisone, androstenedione and AEA might be suitable biomarkers because they met only two of the three criteria, but needed to be validated in the future. The rest biomarkers were unsuitable because they mostly showed no significant intergroup differences, blunt time-dependent changes and poor relative stability.

Effects of oxytocin administration on salivary sex hormone levels in autistic and neurotypical women

Background

Oxytocin administration, which may be of therapeutic value for individuals with social difficulties, is likely to affect endogenous levels of other socially relevant hormones. However, to date, the effects of oxytocin administration on endogenous hormones have only been examined in neurotypical individuals. The need to consider multi-hormone interactions is particularly warranted in oxytocin trials for autism due to evidence of irregularities in both oxytocin and sex steroid systems.

Methods

In this double-blind cross-over study, saliva samples were collected from 16 autistic and 29 neurotypical women before and after intranasal administration of 24 IU oxytocin or placebo. Oestradiol, testosterone, and oxytocin levels were quantified in saliva samples. Participants also completed the Autism-Spectrum Quotient (AQ) and Empathy Quotient (EQ) questionnaires.

Results

Distinct patterns of change in testosterone and oestradiol levels pre- to-post-administration were observed in autistic relative to neurotypical women (ANCOVA, p < 0.05 main effect of Group), controlling for sample collection time. The mean percent change oestradiol was + 8.8% for the autism group and − 13.0% for the neurotypical group (t = 1.81, p = 0.08), while the mean percent change testosterone was + 1.1% in the autism group and − 12.6% in the neurotypical group (t = 1.26, p = 0.22). In the oxytocin condition, the mean percent change oestradiol was + 12.6% in the autism group and − 6.9% in the neurotypical group (t = 1.78, p = 0.08), while the mean percent change testosterone was + 14.4% in the autism group and − 15.2% in the neurotypical group (t = 3.00, p = 0.006). Robust regression confirmed that group differences in percent change hormone levels were not driven by a small number of influential individuals. Baseline hormone levels did not differ between groups when considered individually. However, baseline testosterone relative to oestradiol (T:E2 ratio) was higher in autistic women (p = 0.023, Cohen’s d = 0.63), and this ratio correlated positively and negatively with AQ and EQ scores, respectively, in the combined sample.

Limitations

Further studies with larger and more diverse autistic sample are warranted to confirm these effects.

Conclusions

This study provides the first evidence that oxytocin influences endogenous testosterone levels in autistic individuals, with autistic women showing increases similar to previous reports of neurotypical men. These findings highlight the need to consider sex steroid hormones as a variable in future oxytocin trials.

Circadian rhythm and its association with birth and infant outcomes: research protocol of a prospective cohort study

BACKGROUND

Circadian rhythm plays an important role as our internal body's clock that synchronizes behavior and physiology according to the external 24-h light-dark cycle. Past studies have associated disrupted circadian rhythm with higher risk of miscarriages, preterm birth and low birth weights. This paper described the protocol of a prospective cohort study which aims to determine the circadian rhythm in pregnant women, identify its association with maternal factors during pregnancy, gestational weight gain, birth and infant outcomes.

METHODS

Ten government maternal and child health clinics in Kuala Lumpur, Malaysia will be randomly selected. Sample size of 438 first-trimester pregnant women will be followed-up until the birth of their infant. Salivary melatonin and cortisol concentration among subsample will be determined using enzyme-linked immunosorbent assay. Data on sleep quality, psychological distress and morningness/eveningness chronotype of pregnant women will be collected using validated questionnaires. Pedometer will be used to measure 5-day physical activity data. Total gestational weight gain will be determined at the end of pregnancy. Utilization of 3-day food record is to capture meal timing and nutrient intake. All measurements will be done in 2nd and 3rd trimester. Birth outcomes will be collected through clinic records and Centers for Disease Control and Prevention (CDC) Neonatal questionnaire. Infants will be followed-up at 6 and 12 months old to obtain anthropometric measurements.

DISCUSSION

There is a growing recognition of the role of maternal circadian rhythm, which entrains fetal circadian rhythms that may subsequently have long-term health consequences. The present study will identify the effect of circadian rhythm on pregnancy outcomes and infant growth in the first year of life.