Saliva Cortisol Concentrations Research Articles

Associations between second to fourth digit ratio, cortisol, vitamin D, and body composition among Polish children

Associations between body characteristics (body composition: fat mass, muscle mass, cell, and water mass as well as body proportion—BMI), the 2D:4D digit ratio, and the concentrations of cortisol and vitamin (25-OH)D among Polish children have not been studied before. A total of 133 (73 girls and 60 boys) healthy Polish children aged 7–11 years were examined. The investigation was divided into three parts: measuring (the length of the second and fourth fingers in both hands, body composition, and body height and mass), questionnaires (socioeconomic status), and laboratory investigations (25-OH vitamin D and cortisol concentrations in saliva measured with ELISA methods). Boys with digit ratios below 1 had lower vitamin D concentration than those with digit ratios equal to or higher than 1 (Z = − 2.33; p = 0.019). Only boys with the male-typical pattern of 2D:4D digit ratio tended to have a lower 25-OH vitamin D concentration in saliva. Thus, it might indicate an effect of prenatal programming on the concentrations of steroid hormones in later life. Neither vitamin D, 2D:4D digit ratio nor the cortisol level was associated with the body components or proportions. More studies are needed to evaluate the molecular and genetic background of this phenomenon.

Salivary cortisol concentrations changes in horses during daily routine

Article Details: Received: 2020-10-20 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.1-4 Abstract The aim of the study was to observe the salivary concentrations of cortisol in horses during daily routine over the course of four weeks lasting experiment in three different stages of day to monitor the changing values of cortisol in horse saliva during the day. Saliva was obtained from 12 Slovak warmblood horses – 1 stallion, 6 mares and 5 geldings. In the experiment we focused purely on changes of salivary cortisol concentrations over the course of the daily routine.The results shown us multiple significant changes between individual sample collections and thus, we can state that according to our results the highest concentration of cortisol in horse saliva is in the morning and it decreases throughout the day with lowest measured concentrations being in the final sample collection of the day (at 22:00). These changes had no visible effect on horses´ organism throughout entirety of the experiment and were caused due to horses daily rhythm. Keywords: horse, cortisol, saliva, rest, daily routine References Bohak, Zs, Szabo, F, Beckers, J-F, Melo de Sousa, N, Kutasi, O., Nagy, K, Szenci, O. 2013. Monitoring the circadian rhythm of serum and salivary cortisol concentrations in the horse . Domest. Anim. Endocrinol. 45:38-42. https://doi.org/10.1016/j.domaniend.2013.04.001 Contreras-Aguilar, MD, Lamy, E, Escribano, D, Ceron, JJ, Tecles, F, Quiles, AJ, Hevia, ML. 2020. Changes in salivary analytes of horses due to circadian rhythm and season: A Pilot Study. Animals. 10(9):1486. https://doi.org/10.3390/ani10091486 Halo, M, Hollý, A, Mlynekova, E, Polyakova, L, Horný, M, Kovalcik, E. 2009. Influence feeding and training on the metabolic profil sport horses . J Cent. Eur. Agric. 10(4):411-416. Halo, M, Strapak, P, Mlynekova, E, Kovalcik, E, Horný, M. 2008. Influence stres on the training process of the horses. J. Cent. Eur. Agric. 9(1):217-224. Ille, N, von Lewinski, M, Erber, M, Wulf, M, Aurich, J, Mostl, E, Aurich, C. 2013. Effects of the level of experience of horses and their riders on cortisol release, heart rate and heart rate variability during a jumping course. Anim. Welf. 22:457-465. 10.7120/09627286.22.4.457 Irvine, CHG, Alexander, SL. 1994. Factors affecting the circadian rhythm in plasma cortisol concentrations in the horse. Domest. Anim. Endocrinol. 11(2):227-238. https://doi.org/10.1016/0739-7240(94)90030-2 Kang, O-D, Lee W-S. 2016. Changes in salivary cortisol concentration in horses during different types of exercise . Asian-Australas J Anim Sci. 29(5):747-752. 10.5713/ajas.16.0009 Kang, O-D, Yun Y-M. 2016. Influence of Horse and Rider on Stress during Horse-riding Lesson Program. Asian Australas J Anim Sci. 29(6):895-900. 10.5713/ajas.15.1068 Leal, BB, Alves, GES, Douglas, RH, Bringel, B, Young, RJ, Haddad, JPA, Viana, WS, Faleiros, RR. 2011. Cortisol circadian rhythm ratio: A simple method to detect stressed horses at higher risk of colic? Equine Vet. J. 31:188-190. https://doi.org/10.1016/j.jevs.2011.02.005 Massanyi, P, Stawarz, R, Halo, M, Formicki, G, Lukac, N, Cupka, P, Schwarcz, P, Kovacik, A, Tusimova, E, Kovacik, J. 2014. Blood concentration of copper, cadmium, zinc and lead in the horses and its relation to hematological and biochemical parameters. J. Environ. Sci. Health A. 49:973-979. 10.1080/10934529.2014.894322 Peeters, M, Sulon J, Beckers J-F, Ledoux D, Vandenheede M. 2011. Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge . Equine Vet J. 43(4):487-493. 10.1111/j.2042-3306.2010.00294.x Schmidt, A, Mostl, E, Wehnert, Ch, Aurich, J, Muller, J, Aurich, Ch. 2010. Corisol release and heart rate variability in horses during road transport . Hormones Behaviour. 57: 209-215. 10.1016/j.yhbeh.2009.11.003 Strzelec, K, Kankofer, M, Piertzak, S. 2011. Cortisol concentration in the saliva of horses subjected to different kinds of exercise. Act Vet. Brno. 80:101-105. 10.2754/avb201180010101 Stull, CL, Morrow, J, Aldridge, BA, Stott, JL, McGlone, JJ. 2008. Immunophysiological responses of horses to 12-hour rest during 24 hours of road transport. Vet. Rec. 162:609-614. 10.1136/vr.162.19.609 Van der Kolk, JH, Nachreiner, RF, Schott HC, Refsal KR, Zanella AJ. 2001. Salivary and plasma concentration of cortisol in normal horses and horses with Cushing´s disease. Equine Vet J. 33(2):211-213. 10.1111/j.2042-3306.2001.tb00604.x

Measuring inter-individual differences in stress sensitivity during MR-guided prostate biopsy

People often experience high level of distress during invasive interventions, which may exceed their coping abilities. This may be in particular evident when confronted with the suspicion of cancer. Taking the example of prostate biopsy sampling, we aimed at investigating the impact of an MRI guided prostate biopsy on the acute stress response and its mechanistic basis. We recruited 20 men with a clinical suspicion of prostate cancer. Immediately before an MRI guided biopsy procedure, we conducted fMRI in the same scanner to assess resting-state brain connectivity. Physiological and hormonal stress measures were taken during the procedure and associated with questionnaires, hair cortisol levels and brain measures to elucidate mechanistic factors for elevated stress. As expected, patients reported a stress-related change in affect. Decreased positive affect was associated with higher hair but not saliva cortisol concentration. Stronger use of maladaptive emotion regulation techniques, elevated depression scores and higher within-salience-network connectivity was associated with stronger increase in negative affect and/or decrease of positive affect during the procedure. While being limited in its generalization due to age, sample size and gender, our proof of concept study demonstrates the utility of real-life stressors and large-scale brain network measures in stress regulation research with potential impact in clinical practice.

ПСИХОФИЗИОЛОГИЧЕСКИЕ И БИОХИМИЧЕСКИЕ ПОДХОДЫ К ОЦЕНКЕ УРОВНЯ СТРЕССА У СТУДЕНТОВ-МЕДИКОВ

The aim of the study was development of new approaches to assessment of stress response level in medical students at different periods of educational activity based on complex analysis of psychophysiological and biochemical stress markers. Material and methods. With the help of psychophysiological and biochemical methods in the dynamics of the of the study year, an assessment of the level of stress in 29 medical students was made. At respondents estimated the level of anxiety, alarm, defined features of the endogenous account of time. The level of cortisol in saliva was determined by enzyme immunoassay. Results. The content of cortisol in saliva at the beginning of the semester was taken as a base line. At the end of the semester, the concentration of cortisol in saliva significantly decreased by more than an order of magnitude (p = 0.003). The level of situational anxiety at the beginning of the semester in the group of students corresponded to a moderate level. At the end of the semester, anxiety was significantly higher (p = 0.0002). Conclusion. They found a mirror picture between psychoemotional and biochemical markers of stress: the anxiety of respondents increased at the end of the semester, and the level of salivary cortisol was higher at the beginning of the study year

Effect of growth and parturition on hair cortisol in Holstein cattle.

The effect of growth and parturition on hair cortisol concentrations of cattle was investigated. Plasma, saliva, and hair (black and white from the shoulders and hip) samples were collected from calves at 6 and 24weeks old and from dairy cattle at the dry (1 and 2months prepartum) and lactation (10, 50, 150, and 250days postpartum) periods. Plasma and saliva cortisol concentrations were lower in 24-week-old calves than those of 6-week-old calves, and hair cortisol concentrations decreased regardless of color and position. In 6-week-old calves, hair cortisol concentrations differed between sampling positions, but this difference was not observed in 24-week-old calves. Plasma and saliva cortisol concentrations increased before parturition until 10days postpartum then decreased until 50days postpartum. The same trend was observed in the cortisol concentrations of white hair. Contrarily, cortisol concentrations in black hair remained unchanged and was lower than that in white hair. Hair cortisol concentration can vary greatly depending on the location on the body, hair color, cattle age, or parturition. When this method is used, all of the above factors must be considered.

Space allowance determination by considering its coeffect with toy provision on production performance, behavior and physiology for grouped growing pigs

Increasing space allowance and enhancing environmental enrichment are two approved solutions to improve pig welfare in modern housing systems, while limited research regarding their interactions could be found. To determine the proper stocking density for growing pigs under China's production conditions, an experiment with a 3 × 2 factorial arrangement (three levels of space allowance × with/without toys) was conducted to evaluate the effects of space allowance and toy provision on the production performance, behavior and physiology of the pigs from the 7th to 13th week of age. Two hundred and sixteen pigs were randomly allocated to pens with the space allowances of 0.5, 0.7 and 0.9 m2/pig, and the group size in each pen was fixed at 18. The results showed that the average daily gain (ADG) and feed conversion ratio (FCR) of the pigs with a space allowance of 0.5 m2/pig significantly decreased (P<0.05), while the average daily feed intake (ADFI) did not differ among the groups. Pigs housed in the lower space allowance of 0.5 m2/pig spent more time fighting and feeder occupying and less time lying and resting (P<0.05). With larger space allowances of 0.7 and 0.9 m2/pig, the surface temperature of the pig body in the middle and later stages after grouping was significantly lower (P<0.05). Toy provision inside the pens effectively decreased the water consumption of pigs at 0.5 m2/pig (P<0.01), while no difference was observed in body surface temperature and saliva cortisol concentration among all groups (P>0.05). Pigs gained more weight with toy provision, and their impact was especially enhanced as floor area decreased. Significant interacting effects of space allowance and toy provision on excessive drinker and feeder occupation and negative social behavior were observed (P<0.05). It is concluded that a higher space allowance is beneficial to weight gain, feed conversion and welfare of growing pigs. Toy provision can greatly reduce the excessive occupying behavior and aggression of pigs in barren and crowded environments, indicating that it could improve the growing pig's welfare by enriching the pen environment when the space allowance is limited at the commercial level. Space allowances ranging from 0.7–0.9 m2/pig with toy provision are suggested for intensively growing pigs under China's production conditions.

Aptamer-Based Lateral Flow Biosensor for Rapid Detection of Salivary Cortisol

We have developed a disposable point-of-care (POC) aptamer-based biosensor for the detection of salivary cortisol. Nonstressful and noninvasive sampling of saliva compared to that of blood makes saliva an attractive biological matrix in developing POC devices for biomarker monitoring. Aptamers are attractive as recognition elements for multiple reasons, including their specific chemical synthesis, high stability, lack of immunogenicity, and cell-free evolution. A duplex aptamer conjugated to the surface of Au nanoparticles (AuNPs) by Au–S bonds is utilized as the sensor probe in a lateral flow assay (LFA) device. The addition of saliva samples containing cortisol makes the cortisol–aptamer undergo conformational changes and dissociate from the capture probe. Increasing cortisol concentration in the dispensed saliva sample results in increased dissociation and leads to increased binding of AuNP conjugate on the test line. Therefore, the color intensity of the test line on the LFA is a direct function of the concentration of cortisol in saliva. This simple and fast method provides detection in the cortisol range of ∼0.5–15 ng/mL, which is in the clinically accepted range for salivary cortisol. The limit of detection was 0.37 ng/mL, and the accuracy was confirmed by enzyme-linked immunosorbent assay (ELISA) testing results. High selectivity was observed for salivary cortisol against other closely related steroids and stress biomarkers present in saliva.

Rider effects on horses’ conflict behaviour, rein tension, physiological measures and rideability scores

Many breeding organisations include a subjective scoring of rideability by a professional rider into their evaluation of sports horses, but the consistency and reliability of the scoring system is debateable. The aim of this study was to investigate (i) whether professional riders agree in their scoring of rideability, and (ii) whether rideability scores are affected by rein tension, horse conflict behaviour, heart rate, and salivary cortisol, and (iii) whether riders induce different levels of conflict behaviour and physiological responses in the horses. Ten professional, female riders each rode 10 dressage horses (level M German scale; n = 100 combinations) through a standardised dressage test (10 min warm-up followed by a 4-min test) and subsequently scored the horses for rideability on the official 1–10 scale (1 = poor to 10 = excellent) from the Danish Riding Federation. Rein tension, horse heart rate, saliva cortisol and conflict behaviour were measured for each rider-horse pair. The riders were inconsistent in their scoring of rideability to the individual horses, e.g. scores for one of the horses ranged from 1 to 8. There was a significant effect of rider (P = 0.003) and the frequency of conflict behaviour (undesired head movements: P < 0.001, breaking the gait: P = 0.013, and other evasive behaviour: P = 0.032) on rideability scores, i.e. the more conflict behaviour the lower the score. There was no significant effect of rein tension and the physiological measures on rideability scores. However, there was a significant effect of rider on rein tension, horses’ heart rate and increases in saliva cortisol concentrations and a tendency for some types of conflict behaviour, suggesting that some riders induced more discomfort in the horses. Future studies could help shed light on which elements of riding style are particularly important for sports horse welfare. In conclusion, this study found a large variation in rideability scores assigned to ten sports horses by ten professional riders. Rideability scores were dependent on the level of horse conflict behaviour, but not rein tension and physiological measures. Further studies are needed to improve the objectivity, consistency and reliability of rideability assessment of sports horses.

Cortisol daily rhythm in saliva of healthy school children

To investigate the daily rhythm of cortisol levels in saliva of school children. Probands (10-14 years, both genders) were recruited via personal contact and school visits. Exclusion criteria included hormonal and dental treatments during the trial, pharmaceuticals containing cortisol, or poor oral hygiene. Each volunteer collected 20 saliva samples during one day at defined times starting immediately after waking up and ending at night. Additionally, they completed a sampling diary. Saliva samples were analysed in duplicate using a commercial cortisol luminescence kit. Cortisol concentration in saliva followed a daily rhythm. Within 20 minutes after waking up cortisol reached the highest level of 9.69 (+/-3.89) nmol/L. After 90 minutes cortisol concentration decreased linearly by 50% and stagnated at 4.14 (+/-1.93) nmol/L for 3 to 8 hours. Thereafter, levels decreased gradually reaching almost zero after 14 hours. Overall, no gender-specific differences in saliva cortisol levels were observed except for 3 time points: 3, 10 and 11 hours after waking. This study establishes guidelines for a normal secretion pattern, plus explores pain level measurements and their correlation to saliva cortisol levels in this age group.

Simultaneous quantification of cortisol and cortisone in serums and saliva from depressive patients by supported liquid extraction coupled to HPLC–MS/MSs

Cortisol and cortisone are 2 important glucocorticoids produced in the human hypothalamus–pituitary–adrenal (HPA) axis that respond to stress. An analytical method to determinate cortisol and cortisone in serum and saliva using high-performance liquid chromatography–tandem mass spectrometry following a supported liquid extraction (SLE) was developed. Serum and saliva samples of 0.2 mL were extracted by SLE three times using 0.4 mL of methyl tert-butyl ether each time. The chromatographic separation was obtained on an Agilent Poroshell column using a 0.01% formic acid buffer and acetonitrile (60:40, v/v) as the solvent with a flow rate of 0.3 mL/min. Optimized quantitative mass transitions for cortisol, cortisone, and cortisone d-4 were 363.2/121.0 (m/z), 361.2/163.1 (m/z), and 367.1/270.7 (m/z), respectively. The method validation was achieved according to regulatory guidance. The lower limit of quantification (LLOQ) in serum were 2 ng/mL for cortisol and 1 ng/mL for cortisone, and the LLOQ in saliva were 0.1 ng/mL for cortisol and 0.2 ng/mL for cortisone. The developed method showed convenient and efficient extraction, a lower LLOQ, and a short running time. Modest correlations between serum and saliva cortisol and cortisone concentrations were found. The method was successfully applied in assessing the HPA condition of patients with depressive disorders.

Dietary fatty acids modulate cortisol concentrations and social dominance during social confrontations in adolescent male guinea pigs

The hypothalamic-pituitary-adrenal (HPA)-axis and related glucocorticoid concentrations regulate physiology and behavior, which can be modulated by nutritional conditions, particularly by the dietary fatty acid composition. Omega-3 polyunsaturated fatty acids (PUFAs) have been shown to promote hypothalamic-pituitary-adrenal (HPA)-axis functions, whereas saturated fatty acids (SFAs) in general produce adverse effects and even increase baseline glucocorticoid concentrations. Glucocorticoids (e.g. cortisol) were further documented to modulate the establishment of dominance relationships, while the involvement of dietary fatty acids remains understudied. This study focused on different effects of PUFAs and SFAs on cortisol concentrations and social dominance in male guinea pigs. Three groups of animals were maintained on diets high in PUFAs (10 % w/w walnut oil), SFAs (10 % w/w coconut fat), or on an untreated control diet starting already prenatally. During adolescence, at an age of 60, 90, and 120 days, each individual's saliva cortisol concentrations and hierarchy index (calculated by initiated and received agonistic behavior) were measured during basal group housing conditions and stressful social confrontations with unfamiliar individuals of the other groups. SFA males showed highest baseline cortisol concentrations, lowest cortisol responses to social confrontations, and became subdominant. PUFA and control males showed significant cortisol responses. However, while control males became dominant during social confrontations, the hierarchy index in PUFA males decreased with age. Individual hierarchy indices during consecutive social confrontations revealed a high consistency. The findings presented here indicate that dietary fatty acids differently affect HPA-axis functions and social dominance but the underlying mechanisms remain to be determined.

The intensity of physiological and behavioral responses of horses to predator vocalizations

BackgroundPredatory attacks on horses can become a problem in some parts of the world, particularly when considering the recovering gray wolf populations. The issue studied was whether horses transformed by humans and placed in stable-pasture environments had retained their natural abilities to respond to predation risk. The objective of the study was to determine the changes in cardiac activity, cortisol concentrations, and behavior of horses in response to the vocalizations of two predators: the gray wolf (Canis lupus), which the horses of the breed studied had coevolved with but not been exposed to recently, and Arabian leopard (Panthera pardus nimr), from which the horses had been mostly isolated. In addition, we hypothesized that a higher proportion of Thoroughbred (TB) horse ancestry in the pedigree would result in higher emotional excitability in response to predator vocalizations. Nineteen horses were divided into groups of 75%, 50% and 25% TB ancestry. The auditory test conducted in a paddock comprised a 10-min prestimulus period, a 5-min stimulus period when one of the predators was heard, and a 10-min poststimulus period without any experimental stimuli.ResultsThe increase in heart rate and saliva cortisol concentration in response to predator vocalizations indicated some level of stress in the horses. The lowered beat-to-beat intervals revealed a decrease in parasympathetic nervous system activity. The behavioral responses were less distinct than the physiological changes. The responses were more pronounced with leopard vocalizations than wolf vocalizations.ConclusionsThe horses responded with weak signs of anxiety when exposed to predator vocalizations. A tendency towards a stronger internal reaction to predators in horses with a higher proportion of TB genes suggested that the response intensity was partly innate. The more pronounced response to leopard than wolf may indicate that horses are more frightened of a threatening sound from an unknown predator than one known by their ancestors. The differing response can be also due to differences in the characteristic of the predators’ vocalizations. Our findings suggested that the present-day horses’ abilities to coexist with predators are weak. Hence, humans should protect horses against predation, especially when introducing them into seminatural locations.

Variability of Stress Indicators in Jumping Horses in Parkour Due to Horse Age and Competitive Season

Abstract Aiming to determine the variability in stress indicators due to horse age and competitive season (May, July, September) in jumping horses in parkour, research was performed on 14 studs (7 younger, and 7 older) trained and bred in the same conditions. The stress indicators (heartbeats, cortisol, glucose, and lactate concentrations in saliva) were measured or sampled before, during and at the end of the training - parkour jumping. The significance of the differences in stress indicators between the horse age classes regarding the competitive season was tested by Tukey’s test. Based on determined results it could be concluded that all stress indicators, during the entire competitive season, were higher in younger (less experienced) than in older (more experienced) horses. Furthermore, all stress indicators, with the exception of heartbeats, were highest in the peak of competitive season (July), while the lowest values of all stress indicators were determined at the end of competitive season (September). Monitoring of stress indicators, especially heartbeats, could be used for routine evaluation of horse preparedness for a particular activity.

Impact of short-term hydrocortisone intake on pituitary and adrenal function in healthy young male subjects.

The aim of this study was to evaluate the impact of short-term therapeutic hydrocortisone intake on pituitary and adrenal function in healthy young male subjects. Ten physically active men received 50 mg/per day of hydrocortisone at 8:00 a.m. for 5 days. Cortisol, DHEA, and ACTH concentrations in plasma, and cortisol and DHEA concentrations in saliva were determined the week before, just before (8:00 a.m.) and 2 h after (10:00 a.m.) drug ingestion on days 1, 3, and 5 of treatment and day 1 post treatment. Hydrocortisone intake induced a significant increase in both plasma cortisol (×3) and saliva cortisol (×10) concentrations 2 h after administration. Plasma and saliva DHEA concentrations were significantly decreased, as were plasma ACTH concentrations, 2 h after administration, with an increase in the cortisol/DHEA and cortisol/ACTH ratios. However, no change in cortisol, DHEA, ACTH, cortisol/DHEA, or cortisol/ACTH was observed 24 h after the last intake during treatment or post treatment, except for a downward trend in saliva DHEA at days 3 and 5. The correlations between plasma and saliva cortisol, DHEA, and cortisol/DHEA were significant: respectively, r = 0.80, r = 0.80, and r = 0.88. Once-daily oral therapeutic administration of hydrocortisone for 5 days altered adrenal DHEA secretion by inhibiting pituitary ACTH, but this effect seemed transient without significant impairment of basal adrenal or pituitary function 24 h after administration. Given the high correlations between plasma and saliva, saliva samples may be offered as a sensitive surrogate for blood sampling to estimate adrenal and pituitary function.

Assessment of prenatal stress-related cortisol exposure: focus on cortisol accumulation in hair and nails.

Prenatal stress adversely affects offspring development. Although cortisol is hypothesized to be a key mediator of stress-induced developmental deficits, determining the amount of fetal cortisol exposure produced by maternal stress has proved challenging. Current approaches, such as measuring cortisol concentrations in maternal plasma, saliva, or urine, amniotic fluid, fetal plasma, or cord blood, all have significant limitations for assessing cumulative fetal cortisol exposure over time. A recently emerging approach is to measure cortisol concentrations in maternal hair and/or newborn hair or nail samples. Maternal hair cortisol potentially shows long-term production across each trimester of pregnancy, whereas neonatal hair or nail cortisol is thought to reflect mainly third trimester hormone accumulation. This review first describes fetal adrenocortical development, placental cortisol metabolism, and the various sources of fetal cortisol exposure across pregnancy. We then summarize the results obtained from "classical" methods of assessing prenatal cortisol exposure prior to the advent of hair and nail cortisol measurement. Lastly, we discuss the initial development and validation of the hair cortisol methodology, its subsequent application to studies of chronic stress, and recent findings regarding maternal and neonatal hair or nail cortisol concentrations in relation to prenatal stress and other variables of interest.

Increase in cortisol concentration due to standardized bright and blue light exposure on saliva cortisol in the morning following sleep laboratory

Research studies on LED light exposure and cortisol are inconsistent and not comparable due to different types of light, exposure times, and sample sizes. Therefore, one hour of standardized exposure LED light at different intensities and the spectral composition during the post-awakening phase at 7:30 were compared. A sample of 23 (Study 1) and 26 (Study 2) healthy males were randomly assigned to: 1) bright white light (414 lux) and 2) dim darkened light (<2 lux) as well as 3) red light (235 lux) and 4) blue light (201 lux) exposure conditions. Results from repeated measures ANOVA confirm that light exposure affects the cortisol concentration. Study 1 revealed an increase in the saliva cortisol concentration after bright light exposure compared to dim light. An increase in the cortisol concentration of blue light compared to red light (Study 2) and dim light was found. This study shows that bright light and blue light affect the cortisol response in contrast to dim light and red light conditions. The HPA axis showed a stimulatory effect by bright versus dim light and different wavelengths of light exposure. Lay summary The effects of LED light exposure on the stress hormone cortisol were investigated. The light exposure took place during the hours people would start working at the office. The results showed that after one hour of exposure to bright light or blue light the stress hormones increase in contrast to dim light and red light conditions. Thus, stress hormones can be altered by the types of light people are exposed to.

Chronic elevation of plasma cortisol causes differential expression of predominating glucocorticoid in plasma, saliva, fecal, and wool matrices in sheep

There is increasing interest in using nonblood measures of glucocorticoids to assess the physiological response to chronic stress conditions. In sheep, cortisol has been measured in various matrices including saliva, feces, and wool, but comprehensive studies of the relationship between plasma concentrations of cortisol and concentrations in these nonblood matrices are lacking. Therefore, we tested the hypothesis that administration of cortisol to sheep would result in elevated concentrations of cortisol in blood, saliva, feces, and wool. Merino ewes were administered with saline or 2 mg/kg BW/d hydrocortisone acetate (HCA) by intramuscular (i.m.) injection for 28 d. This treatment was imposed to mimic circulating cortisol concentrations experienced during periods of chronic stress. Cortisol and cortisone were directly measured in plasma, saliva, and wool before, during, and after treatment with saline or HCA. A 14-d pre-treatment and a 14-d post-treatment period were used to measure time taken for glucocorticoid concentrations in each of the matrices to return to baseline levels. Cortisol was also measured in feces before, during, and after treatment. Wool growth was also measured. Before treatment, there was no difference in the concentration of cortisol or cortisone in plasma, saliva, feces, or wool in animals treated with saline or HCA. In contrast, treatment with HCA increased (P < 0.05) concentrations of both cortisol and cortisone in plasma, saliva, and wool and of cortisol in feces. In plasma, cortisol concentrations were higher than cortisone (P < 0.05), whereas saliva cortisol and cortisone concentrations did not differ significantly. In wool, the concentration of cortisone was about 19-fold higher than that of cortisol during treatment and post-treatment periods. Treatment with HCA inhibited wool growth. These results demonstrate that an increase in glucocorticoids in the blood of sheep is reflected in increases in saliva (after 7 d of treatment), feces (21 d), and wool (14 d). Therefore, measures of glucocorticoids in these matrices may provide a measure of activation of the adrenal glands over time in sheep, thereby providing a retrospective indicator of chronic stress. With respect to wool, it appears that cortisol is predominantly metabolized to cortisone in the skin or wool follicle and is stored as cortisone. Therefore wool cortisone may also provide an important measure in quantifiying chronic stress in sheep.

Cortisol secretion predicts functional macro-scale connectivity of the visual cortex: A data-driven Multivoxel Pattern Analysis (MVPA)

BackgroundFunctional connectivity is a fundamental principle of brain organization. Cortisol, the end product of the hypothalamic–pituitary–adrenal axis, is a potent modulator of brain functions. Previous studies investigating the association between cortisol levels on brain connectivity are, however, limited to specifica priori defined brain networks. Such hypothesis-driven approaches only partly capture the full extent of spatial modulatory effects that cortisol exerts on brain connectivity. Consequently, the aim of this study was a data-driven identification of brain regions where connectivity patterns covary significantly with cortisol levels. MethodsEighty-eight healthy right-handed individuals participated in a task-independent fMRI-resting-state functional connectivity (rsFC) measurement. The cortisol concentrations in saliva were measured at eight points in time around the resting state measurement. Using a multi-voxel pattern analysis (MVPA), seed regions were identified whose activity covaried strongest with cortisol levels. Seed-to-voxel analyses were then performed to isolate corresponding networks affected by cortisol variation. ResultsThe MVPA identified three regions in the primary and secondary visual cortex where connectivity patterns were associated with cortisol secretion. Seed-to-voxel analysis revealed large lateral connectivity clusters that mainly correspond to the salience and control network, but also to auditory and pericentral regions. Subsequent dose-response analysis suggests that cortisol levels below ∼10 nmol/L weakly influenced connectivity between the identified regions. DiscussionThe results indicate a dose-dependent association between cortisol levels and the rsFC of the visual cortex to several lateral brain regions associated with perception, attention, cognition, salience mapping and motor actions. It is possible that the effects of cortisol on cognitive functions may be (at least partially) mediated by cortisol effects on the underlying sensory processes.

Pain Response to Open Label Placebo in Induced Acute Pain in Healthy Adult Males.

Open label placebos with patient education are effective in reducing chronic pain, and recent studies on their effect on pain have established interest in this field. Nevertheless, data on their effect on acute pain are scarce, and on hyperalgesia and allodynia, absent. This study assessed the effect of open label placebos on acute pain in healthy adult males and the influence of placebo education. Thirty-two healthy males were included in this prospective, randomized, assessor-blinded crossover, single-center study assessing pain intensities (via numeric rating scale), area of hyperalgesia (von Frey filament), and allodynia (dry cotton swab) in a pain model utilizing intracutaneous electrical stimulation. The authors compared the effect of intravenous open label placebo on pain compared to no treatment. The authors further examined the effect of placebo on hyperalgesia and allodynia, and the influence of education (short vs. detailed) before placebo application. Saliva cortisol concentrations were also measured. Pain ratings (median, first to third quartile) were 21% lower during placebo treatment compared to no treatment, 4.0 (3.2 to 4.9) versus 5.1 (4.7 to 5.4), respectively (P = 0.001). The areas of hyperalgesia and allodynia were lower during placebo treatment compared to no treatment (hyperalgesia, 30 cm [17 to 47] vs. 55 cm [42 to 68], P = 0.003; allodynia, 24 cm [11 to 39] vs. 45 cm [31 to 62], P = 0.007). This corresponds to reductions of 47%. The extent of placebo education had no effect on pain. Saliva cortisol decreased significantly over time and was under the limit of detectability in the majority of participants in postbaseline measurements in both treatment branches. Baseline cortisol was not associated with the placebo effect or strength applied of current to reach defined pain ratings. Open label placebos might play a role in multimodal analgesic concepts.

Circadian Rhythm of Salivary Immunoglobulin A and Associations with Cortisol as A Stress Biomarker in Captive Asian Elephants (Elephas maximus)

Simple SummarySalivary immunoglobulin A (sIgA) and cortisol concentrations were measured in Asian elephants to determine circadian rhythm effects and the relationship between both biomarkers. Saliva samples were collected every 4 h from 06:00 to 22:00 h for 3 consecutive days (n = 15 samples/elephant). We used enzyme immunoassays for quantification of sIgA and cortisol concentrations. Both sIgA and cortisol followed a circadian rhythm, although the patterns differed. For both, the highest concentrations were in the early morning hours when elephants began the work day; however, sIgA concentrations were more variable during the day. There was no correlation between the two indices because the pattern of sIgA was quartic, while that of cortisol was linear. We provide basic knowledge for further studies using sIgA as a welfare biomarker.Salivary immunoglobulin A (sIgA) has been proposed as a potential indicator of welfare for various species, including Asian elephants, and may be related to adrenal cortisol responses. This study aimed to distinguish circadian rhythm effects on sIgA in male and female Asian elephants and compare patterns to those of salivary cortisol, information that could potentially have welfare implications. Subjects were captive elephants at an elephant camp in Chiang Mai province, Thailand (n = 5 males, 5 females). Salivette® kits were used to collect saliva from each elephant every 4 h from 06:00 to 22:00 h for 3 consecutive days (n = 15 samples/elephant). Enzyme immunoassays were used to quantify concentrations of IgA and cortisol in unextracted saliva. Circadian rhythm patterns were determined using a generalized least-squares method. Both sIgA and cortisol followed a circadian rhythm, although the patterns differed. sIgA displayed a daily quartic trend, whereas cortisol concentrations demonstrated a decreasing linear trend in concentrations throughout the day. There was no clear relationship between patterns of sIgA and salivary cortisol, implying that mechanisms of control and secretion differ. Results demonstrate for the first time that circadian rhythms affect sIgA, and concentrations follow a daily quartic pattern in Asian elephants, so standardizing time of collection is necessary.