Effects of physical and psychological stressors on adolescents’ cortisol levels and self-perceived stress in school

Both, psychosocial stress and exercise in the past have been used as stressors to elevate saliva cortisol and change state anxiety levels. In the present study, high-school students at the age of 14 were randomly assigned to three experimental groups: (1) an exercise group (n = 18), that was running 15 minutes at a medium intensity level of 65-75% HRmax, (2) a psychosocial stress group (n = 19), and (3) a control group (n = 18). The psychosocial stress was induced to the students by completing a standardized intelligence test under the assumption that their IQ scores would be made public in class. Results display that only psychosocial stress but not exercise was able to significantly increase cortisol levels but decreased cognitive state anxiety in adolescents. The psychosocial stress protocol applied here is proposed for use in future stress studies with children or adolescents in group settings, e.g., in school.

Differences in coping, self-efficacy, and external control beliefs between patients at-risk for psychosis and patients with first-episode psychosis

Patients with first-episode psychosis (FEP) often show dysfunctional coping patterns, low self-efficacy, and external control beliefs that are considered to be risk factors for the development of psychosis. Therefore, these factors should already be present in patients at-risk for psychosis (AR). We compared frequencies of deficits in coping strategies (Stress-Coping-Questionnaires, SVF-120/SVF-KJ), self-efficacy, and control beliefs (Competence and Control Beliefs Questionnaire, FKK) between AR (n=21) and FEP (n=22) patients using a cross-sectional design. Correlations among coping, self-efficacy, and control beliefs were assessed in both groups. The majority of AR and FEP patients demonstrated deficits in coping skills, self-efficacy, and control beliefs. However, AR patients more frequently reported a lack of positive coping strategies, low self-efficacy, and a fatalistic externalizing bias. In contrast, FEP patients were characterized by being overly self-confident. These findings suggest that dysfunctional coping, self-efficacy, and control beliefs are already evident in AR patients, though different from those in FEP patients. The pattern of deficits in AR patients closely resembles that of depressive patients, which may reflect high levels of depressiveness in AR patients. Apart from being worthwhile treatment targets, these coping and belief patterns are promising candidates for predicting outcome in AR patients, including the conversion to psychosis

Control of ventricular ciliary beating by the melanin concentrating hormone-expressing neurons of the lateral hypothalamus: a functional imaging survey

The cyclic peptide Melanin Concentrating Hormone (MCH) is known to control a large number of brain functions in mammals such as food intake and metabolism, stress response, anxiety, sleep/wake cycle, memory, and reward. Based on neuro-anatomical and electrophysiological studies these functions were attributed to neuronal circuits expressing MCHR1, the single MCH receptor in rodents. In complement to our recently published work (1) we provided here new data regarding the action of MCH on ependymocytes in the mouse brain. First, we establish that MCHR1 mRNA is expressed in the ependymal cells of the third ventricle epithelium. Second, we demonstrated a tonic control of MCH-expressing neurons on ependymal cilia beat frequency using in vitro optogenics. Finally, we performed in vivo measurements of CSF flow using fluorescent micro-beads in wild-type and MCHR1-knockout mice. Collectively, our results demonstrated that MCH-expressing neurons modulate ciliary beating of ependymal cells at the third ventricle and could contribute to maintain cerebro-spinal fluid homeostasis.

Minderung physiologischer Reaktivität auf psychosozialen Stress durch Taiji-Training - wer profitiert besonders? Eine Untersuchung moderierender Effekte von selbstberichteter dispositioneller psychologischer Stressreaktivität und Achtsamkeit.

Theoretical background and objectives: Stress reducing effects of Taiji practice have been repeatedly reported. The aim of the present study was to investigate which persons benefit the most from Taiji practice in terms of reduced physiological stress reactivity. Methods: We conducted a secondary data analysis of a randomized controlled Taiji trial that significantly lowered stress reactivity of salivary cortisol and alpha-amylase in a Taiji group (n = 26) compared to a control group (n = 23). By using hierarchical regression analyses potential moderating influences of self-reported trait-mindfulness and trait values of general psychological stress reactivity on stress protective effects of a three months Taiji training were examined. Moderator variables were assessed at the beginning of the study using the Freiburg-Mindfulness-Inventory and the Perceived- Stress-Reactivity-Scale. Results: The interaction effect "study group x mindfulness" was significant for stress reactivity of salivary alpha-amylase (p = 0.050). Participants in the Taiji group with higher trait-mindfulness showed a lower salivary alpha-amylase stress reactivity, while in the control group higher trait-mindfulness was associated with higher alpha-amylase stress reactivity. In the control group (p = 0.042) but not in the Taiji group (p = 0.69) salivary cortisol stress reactivity was significantly increased in persons with higher trait-mindfulness scores. We could not find moderating effects of general psychological stress reactivity. Conclusion: Our results suggest that without intervention higher trait-mindfulness is associated with increased physiological stress reactivity. Persons with higher trait-mindfulness seem to benefit the most from practicing Taiji in terms of reduced sympathetic stress reactivity.

Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress

BACKGROUND The presence of social support has been associated with decreased stress responsiveness. Recent animal studies suggest that the neuropeptide oxytocin is implicated both in prosocial behavior and in the central nervous control of neuroendocrine responses to stress. This study was designed to determine the effects of social support and oxytocin on cortisol, mood, and anxiety responses to psychosocial stress in humans. METHODS In a placebo-controlled, double-blind study, 37 healthy men were exposed to the Trier Social Stress Test. All participants were randomly assigned to receive intranasal oxytocin (24 IU) or placebo 50 min before stress, and either social support from their best friend during the preparation period or no social support. RESULTS Salivary free cortisol levels were suppressed by social support in response to stress. Comparisons of pre- and poststress anxiety levels revealed an anxiolytic effect of oxytocin. More importantly, the combination of oxytocin and social support exhibited the lowest cortisol concentrations as well as increased calmness and decreased anxiety during stress. CONCLUSIONS Oxytocin seems to enhance the buffering effect of social support on stress responsiveness. These results concur with data from animal research suggesting an important role of oxytocin as an underlying biological mechanism for stress-protective effects of positive social interactions.

Integrating fragmented evidence by network meta-analysis: relative effectiveness of psychological interventions for adults with post-traumatic stress disorder

BACKGROUND To summarize the available evidence on the effectiveness of psychological interventions for patients with post-traumatic stress disorder (PTSD). METHOD We searched bibliographic databases and reference lists of relevant systematic reviews and meta-analyses for randomized controlled trials that compared specific psychological interventions for adults with PTSD symptoms either head-to-head or against control interventions using non-specific intervention components, or against wait-list control. Two investigators independently extracted the data and assessed trial characteristics. RESULTS The analyses included 4190 patients in 66 trials. An initial network meta-analysis showed large effect sizes (ESs) for all specific psychological interventions (ESs between -1.10 and -1.37) and moderate effects of psychological interventions that were used to control for non-specific intervention effects (ESs -0.58 and -0.62). ES differences between various types of specific psychological interventions were absent to small (ES differences between 0.00 and 0.27). Considerable between-trial heterogeneity occurred (τ 2 = 0.30). Stratified analyses revealed that trials that adhered to DSM-III/IV criteria for PTSD were associated with larger ESs. However, considerable heterogeneity remained. Heterogeneity was reduced in trials with adequate concealment of allocation and in large-sized trials. We found evidence for small-study bias. CONCLUSIONS Our findings show that patients with a formal diagnosis of PTSD and those with subclinical PTSD symptoms benefit from different psychological interventions. We did not identify any intervention that was consistently superior to other specific psychological interventions. However, the robustness of evidence varies considerably between different psychological interventions for PTSD, with most robust evidence for cognitive behavioral and exposure therapies.

Being optimally aroused matters: Effects of a weak stress manipulation on children’s executive functions are moderated by temperament and age

We tested a core assumption of the bidirectional model of executive function (EF) (Blair & Ursache, 2011) indicating that EF is dependent on arousal. From a bottom-up perspective the performance on EF tasks is assumed to be curvilinearly related to arousal, with very high or low levels of arousal impairing EF. N = 107 4-and 6-year-olds’ performance on EF tasks was explored as a function of a weak stress manipulation aiming to raise children’s emotional arousal. EF (Stroop, Flanker, Go/no-go, and Backwards Color Recall) was assessed and stress was induced in half of the children by imposing a mild social evaluative threat. Furthermore, children’s temperament was assessed as a potential moderator. We found that stress effects on children’s EF performance were moderated by age and temperament: 4-year-olds with high Inhibitory Control and high Attentional Focusing were negatively affected by the stressor. However, it is unclear whether these effects were mediated by self-reported arousal. Our findings disconfirmed the hypotheses that adverse effects of the stressor are particularly high in children high on emotional reactivity aspects of temperament and low on self-regulatory aspects of temperament. Further, 6-year-olds did not show any stress effects. Results will be discussed within the framework of the Yerkes-Dodson law and with regard to stress manipulations in children.

Aggravation of cardiac myofibroblast arrhythmogeneicity by mechanical stress

Aims Myofibroblasts (MFBs) as appearing in the myocardium during fibrotic remodelling induce slow conduction following heterocellular gap junctional coupling with cardiomyocytes (CMCs) in bioengineered tissue preparations kept under isometric conditions. In this study, we investigated the hypothesis that strain as developed during diastolic filling of the heart chambers may modulate MFB-dependent slow conduction. Methods and results Effects of defined levels of strain on single-cell electrophysiology (patch clamp) and impulse conduction in patterned growth cell strands (optical mapping) were investigated in neonatal rat ventricular cell cultures (Wistar) grown on flexible substrates. While 10.5% strain only minimally affected conduction times in control CMC strands (+3.2%, n.s.), it caused a significant slowing of conduction in the fibrosis model consisting of CMC strands coated with MFBs (conduction times +26.3%). Increased sensitivity to strain of the fibrosis model was due to activation of mechanosensitive channels (MSCs) in both CMCs and MFBs that aggravated the MFB-dependent baseline depolarization of CMCs. As found in non-strained preparations, baseline depolarization of CMCs was partly due to the presence of constitutively active MSCs in coupled MFBs. Constitutive activity of MSCs was not dependent on the contractile state of MFBs, because neither stimulation (thrombin) nor suppression (blebbistatin) thereof significantly affected conduction velocities in the non-strained fibrosis model. Conclusions The findings demonstrate that both constitutive and strain-induced activity of MSCs in MFBs significantly enhance their depolarizing effect on electrotonically coupled CMCs. Ensuing aggravation of slow conduction may contribute to the precipitation of strain-related arrhythmias in fibrotically remodelled hearts.

Antioxidant supplementation attenuates oxidative stress in patients undergoing coronary artery bypass graft surgery.

Ischemia-reperfusion has been reported to be associated with augmented oxidative stress in the course of surgery, which might be causally involved in the onset of atrial fibrillation (AF), the most common arrhythmia after cardiac surgery. We hypothesized that supplementation of antioxidants and n-3 polyunsaturated fatty acids (n-3 PUFAs) might lower the incidence of AF following coronary artery bypass graft (CABG) surgery. In the present study, by monitoring oxidative stress in the course of CABG surgery, we analyzed the efficacy of vitamins (ascorbic acid and α-tocopherol) and/or n-3 PUFAs (eicosapentaenoic acid and docosahexaenoic acid). Subjects (n = 75) were divided into 4 subgroups: control, vitamins, n-3 PUFAs, and a combination of vitamins and n-3 PUFAs. Fluorescent techniques were used to measure the antioxidative capacity, i.e. ability to inhibit oxidation. Total peroxides, endogenous peroxidase activity, and antibodies against oxidized LDL (oLAb) were used as serum oxidative stress biomarkers. Post-operative increase in oxidative stress was associated with the consumption of antioxidants and a simultaneous onset of AF. This was confirmed through an increased peroxide level and a decreased oLAb titer in control and n-3 PUFAs groups, indicating the binding of antibodies to oxidative modified epitopes. In both subgroups that were supplemented with vitamins, total peroxides decreased, and the maintenance of a constant IgG antibody titer was facilitated. However, treatment with vitamins or n-3 PUFAs was inefficient with respect to AF onset and its duration. We conclude that the administration of vitamins attenuates post-operative oxidative stress in the course of CABG surgery.

The implicit affiliation motive moderates cortisol responses to acute psychosocial stress in high school students

It has been previously shown that the implicit affiliation motive – the need to establish and maintain friendly relationships with others – leads to chronic health benefits. The underlying assumption for the present research was that the implicit affiliation motive also moderates the salivary cortisol response to acute psychological stress when some aspects of social evaluation and uncontrollability are involved. By contrast we did not expect similar effects in response to exercise as a physical stressor. Fifty-nine high school students aged M = 14.8 years were randomly assigned to a psychosocial stress (publishing the results of an intelligence test performed), a physical stress (exercise intensity of 65–75% of HRmax), and a control condition (normal school lesson) each lasting 15 min. Participants’ affiliation motives were assessed using the Operant Motive Test and salivary cortisol samples were taken pre and post stressor. We found that the strength of the affiliation motive negatively predicted cortisol reactions to acute psychosocial but not to physical stress when compared to a control group. The results suggest that the affiliation motive buffers the effect of acute psychosocial stress on the HPA axis.

DNA hypomethylation and oxidative stress-mediated increase in genomic instability in equine sarcoid-derived fibroblasts

It is widely accepted that equine sarcoid disease, the most common skin associated neoplasm in equids, is induced by bovine papillomavirus (BPV-1). Although BPV-1 DNA has been found in almost all examined sarcoids so far, its detailed impact on the horse's host cell metabolism is largely unknown. We used equine fibroblast cell lines originating from sarcoid biopsies to study BPV-1-associated changes on DNA methylation status and oxidative stress parameters. Sarcoid-derived fibroblasts manifested increased proliferation in vitro, transcriptional rDNA activity (NORs expression) and DNA hypomethylation compared to control cells. Cells isolated from equine sarcoids suffered from oxidative stress: the expression of antioxidant enzymes was decreased and the superoxide production was increased. Moreover, increased ploidy, oxidative DNA damage and micronuclei formation was monitored in sarcoid cells. We postulate that both altered DNA methylation status and redox milieu may affect genomic stability in BPV-1-infected cells and in turn contribute to sarcoid pathology.