Toward a causal model of cardiovascular responses to stress and the development of cardiovascular disease

Endocrinological and subjective stress responses in children with depressive, anxiety, or externalizing disorders

In this study, we used a stress test to investigate endocrinological and subjective stress responses of 8- to 14-year-old children with internalizing or externalizing disorders and healthy controls. The sample (N = 170) consisted of clinical and community children. Parents were given a diagnostic interview to diagnose their children's psychiatric condition. We measured saliva cortisol and subjectively experienced arousal in children before and after the Trier Social Stress Test for Children. Children also rated their performance immediately after the stress test, and 1 hr later they rated their positive and negative thoughts about this stressful event. Children with internalizing or externalizing disorders exhibited a blunted cortisol response compared to healthy controls. Depressed children rated their test performance lower and reported more negative thoughts after the test in comparison to healthy controls, anxious children reported more arousal before and after the task, and children with externalizing disorders reported more positive thoughts. In regression analyses, cortisol and subjective stress responses were both predictive of psychiatric disorders. The study extends previous work on the relation between psychiatric disorders and children's stress responses to an experimentally induced stress task by including a broad range of psychiatric disorders and by integrating endocrinological and subjective stress responses.

Blood pressure reactivity to psychological stress is associated with clinical outcomes in patients with heart failure

INTRODUCTION

Cardiovascular (CV) reactivity to psychological stress has been implicated in the development and exacerbation of cardiovascular disease (CVD). Although high CV reactivity traditionally is thought to convey greater risk of CVD, the relationship between reactivity and clinical outcomes is inconsistent and may depend on the patient population under investigation. The present study examined CV reactivity in patients with heart failure (HF) and its potential association with long-term clinical outcomes.

METHODS

One hundred ninety-nine outpatients diagnosed with HF, with ejection fraction ≤40%, underwent an evaluation of blood pressure (BP) and heart rate reactivity to a laboratory-based simulated public-speaking stressor. Cox proportional hazards regression models were used to examine the prospective association between BP and heart rate reactivity on a combined end point of death or CV hospitalization over a 5-year median follow-up period.

RESULTS

Both systolic blood pressure (SBP) and diastolic blood pressure (DBP) reactivity, quantified as continuous variables, were inversely related to risk of death or CV hospitalization (Ps < .01) after controlling for established risk factors, including HF disease severity and etiology. In similar models, heart rate reactivity was unrelated to outcome (P = .12). In models with tertiles of reactivity, high SBP reactivity, compared with intermediate SBP reactivity, was associated with lower risk (hazard ratio [HR] = .498, 95% CI .335-.742, P =.001), whereas low SBP reactivity did not differ from intermediate reactivity. For DBP, high reactivity was marginally associated with lower risk compared with intermediate DBP reactivity (HR = .767, 95% CI .515-1.14, P =.193), whereas low DBP reactivity was associated with greater risk (HR = 1.49, 95% CI 1.027-2.155, P =.0359). No relationship of heart rate reactivity to outcome was identified.

CONCLUSIONS

For HF patients with reduced ejection fraction, a robust increase in BP evoked by a laboratory-based psychological challenge was associated with lower risk for adverse CVD events and may be a novel and unique marker of left ventricular systolic reserve that is accompanied by a more favorable long-term prognosis.

Effects of coping flexibility on cardiovascular reactivity to task difficulty

OBJECTIVE

Coping flexibility refers to an individual's ability to effectively modify his or her coping behavior to better fit the nature of each stressful situation they encounter. More flexible coping is believed to produce more adaptive psychological functioning and physical health.

METHODS

We examined the relationship between coping flexibility and cardiovascular reactivity (CVR) to psychological stress. Challenging tasks of two difficulty levels were presented to 24 men and 24 women aged 18 to 24years. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure were measured.

RESULTS

Change scores (from baseline to reactivity) for SBP and HR responses in the difficult task were higher than those in the easy task and were negatively correlated with coping flexibility during the difficult task but not the easy one.

CONCLUSIONS

The findings suggest that more flexible coping is associated with reduced CVR to a difficult task.

Cardiovascular and autonomic reactivity to psychological stress: Neurophysiological substrates and links to cardiovascular disease

Psychologically stressful experiences evoke changes in cardiovascular physiology that may influence risk for cardiovascular disease (CVD). But what are the neural circuits and intermediate physiological pathways that link stressful experiences to cardiovascular changes that might in turn confer disease risk? This question is important because it has broader implications for our understanding of the neurophysiological pathways that link stressful and other psychological experiences to physical health. This review highlights selected findings from brain imaging studies of stressor-evoked cardiovascular reactivity and CVD risk. Converging evidence across these studies complements animal models and patient lesion studies to suggest that a network of cortical, limbic, and brainstem areas for central autonomic and physiological control are important for generating and regulating stressor-evoked cardiovascular reactivity via visceromotor and viscerosensory mechanisms. Emerging evidence further suggests that these brain areas may play a role in stress-related CVD risk, specifically by their involvement in mediating metabolically-dysregulated or extreme stressor-evoked cardiovascular reactions. Contextually, the research reviewed here offers an example of how brain imaging and health neuroscience methods can be integrated to address open and mechanistic questions about the neurophysiological pathways linking psychological stress and physical health.

Ever at the ready for events that never happen

Stress, whether daily stress, work stress or traumatic stress, is unhealthy. This lecture covers three recent theoretical approaches in explaining the mechanisms underlying the influence of psychological stress on somatic health. It is argued that stress research should focus less on stressors themselves and put more emphasis on prolonged stress responses. Three mechanisms are identified that cause this unhealthy prolonged stress response: first, the partly-proven mechanism of perseverative cognition; second, the mechanism of unconscious stress, which is currently being explored; and third, the notion of the stress response being a default response that is inhibited only when safety is perceived. All three mechanisms are deeply rooted in millions of years of our evolution. Although the dangers of the past have virtually disappeared, many of us remain ever at the ready for events that never happen.

Heritability of heart rate recovery and vagal rebound after exercise

Purpose

The prognostic power of heart rate recovery (HRR) after exercise has been well established but the exact origin of individual differences in HRR remains unclear. This study aims to estimate the heritability of HRR and vagal rebound after maximal exercise in adolescents. Furthermore, the role of voluntary regular exercise behavior (EB) in HRR and vagal rebound is tested.

Methods

491 healthy adolescent twins and their siblings were recruited for maximal exercise testing, followed by a standardized cooldown with measurement of the electrocardiogram and respiratory frequency. Immediate and long-term HRR (HRR60 and HRR180) and vagal rebound (heart rate variability in the respiratory frequency range) were assessed 1 and 3 min after exercise. Multivariate twin modeling was used to estimate heritability of all measured variables and to compute the genetic contribution to their covariance.

Results

Heritability of HRR60, HRR180 and immediate and long-term vagal rebound is 60 % (95 % CI: 48–67), 65 % (95 % CI: 54–73), 23 % (95 % CI: 11–35) and 3 % (95 % CI: 0–11), respectively. We find evidence for two separate genetic factors with one factor influencing overall cardiac vagal control, including resting heart rate and respiratory sinus arrhythmia, and a specific factor for cardiac vagal exercise recovery. EB was only modestly associated with resting heart rate (r = −0.27) and HRR (rHRR60 = 0.10; rHRR180 = 0.19) with very high genetic contribution to these associations (88–91 %).

Conclusions

Individual differences in HRR and immediate vagal rebound can to a large extent be explained by genetic factors. These innate cardiac vagal exercise recovery factors partly reflect the effects of heritable differences in EB.

Is Sex Good for Your Health? A National Study on Partnered Sexuality and Cardiovascular Risk among Older Men and Women

Working from a social relationship and life course perspective, we provide generalizable population-based evidence on partnered sexuality linked to cardiovascular risk in later life using national longitudinal data from the National Social Life, Health and Aging Project (NSHAP) (N = 2,204). We consider characteristics of partnered sexuality of older men and women, particularly sexual activity and sexual quality, as they affect cardiovascular risk. Cardiovascular risk is defined as hypertension, rapid heart rate, elevated C-reactive protein (CRP), and general cardiovascular events. We find that older men are more likely to report being sexually active, having sex more often, and more enjoyably than are older women. Results from cross-lagged models suggest that high frequency of sex is positively related to later risk of cardiovascular events for men but not women, whereas good sexual quality seems to protect women but not men from cardiovascular risk in later life. We find no evidence that poor cardiovascular health interferes with later sexuality for either gender.

Effects of Religious Orientation and Gender on Cardiovascular Reactivity Among Older Adults

Recent attention has focused on the relationship between religiosity and health. Although many pathways have been proposed to account for this relationship, little empirical research has investigated specific pathways in relation to specific physiological functions. This study assessed the roles that religious orientation and gender play in moderating psychophysiological reactivity to laboratory stressors among older adults. Those participants characterized by an intrinsic religious orientation (IO) demonstrated less reactivity than did those characterized by an extrinsic religious orientation. Gender did not influence reactivity. There was some evidence that the effect of religious orientation is more pronounced for interpersonal than cognitive-type stressors, although the strongest findings were evident when stressors were aggregated. The magnitude of these effects suggests that they are of practical significance. Given these results and the known relationship between reactivity and hypertension, it is proposed that IO may result in decreased risk of developing hypertension in older adults.

Cardiovascular, cortisol and coping responses in urban Africans: the SAPBA study

Objectives

To assess the relationships between progression of target-organ damage and cardiovascular, cortisol and coping responses in black urban Africans.

Methods

Urban black African gender groups (n = 200) aged 21–62 years from the Sympathetic Activity and Ambulatory Blood Pressure in Africans study were stratified into normotensive and hypertensive groups. Resting and reactivity Finometer blood pressure, fasting sodium fluoride glucose and salivary cortisol values were obtained before and after applying the Stroop and cold pressor tests. Coping strategies were determined and high-resolution ultrasound carotid intima–media scans were done to determine progression of target-organ damage.

Results

A trend of high-normal resting cortisol values during sampling time 1 was demonstrated in all hypertensive men. Both hypertensive gender groups showed increased vascular responses during both mental stressors. During the cold pressor test, vascular responses predicted sub-clinical atherosclerosis in all hypertensive men, independent of sampling time.

Conclusion

Early morning vascular responses in all the hypertensive men could have occurred secondarily to the permissive effect of cortisol on norepinephrine secretion, with subsequent α-adrenergic vasoconstriction. Their α-adrenergic vascular responses during the cold pressor test, however, predicted sub-clinical atherosclerosis, independent of sampling time and cortisol level.

Do Cardiovascular Responses to Active and Passive Coping Tasks predict Future Blood Pressure over a 10-Month Later?

The study examined whether cardiovascular responses to active or passive coping tasks and single or multiple tasks predicted changes in resting blood pressure (BP) over a ten-month period. Heart rate (HR), BP, cardiac output (CO), and total peripheral resistance (TPR) were measured at rest, and during mental stress tests (mental arithmetic, speech, and cold pressor tasks). A total of 104 eligible participants participated in the initial study, and 77 (74.04%) normotensive adult participants’ resting BP were re-evaluated at ten-month follow-up. Regression analyses indicated that after adjustment for baseline BP, initial age, gender, body mass index, family history of cardiovascular disease, and current cigarette smoking, heighted systolic blood pressure (SBP) and HR responses to an active coping task (mental arithmetic) were associated with increased future SBP (ΔR2 = .060, ΔR2 = .045, respectively). Further, aggregated SBP responsivity (over the three tasks) to the predictor models resulted in significant, but smaller increases in ΔR2 accounting for .040 of the variance of follow-up SBP. These findings suggest that cardiovascular responses to active coping tasks predict future SBP. Further, compared with single tasks, the findings revealed that SBP responses to three tasks were less predictive compared to an individual task (i.e., mental arithmetic). Of importance, hemodynamic reactivity (namely CO and TPR) did not predict future BP suggesting that more general psychophysiological processes (e.g., inflammation, platelet aggregation) may be implicated, or that BP, but not hemodynamic reactivity may be a marker of hypertension.

Reducing involuntary memory by interfering consolidation of stressful auditory information: A pilot study

BACKGROUND AND OBJECTIVES

Intrusive emotional memories were induced by aversive auditory stimuli and modulated with cognitive tasks performed post-encoding (i.e., during consolidation).

METHOD

A between-subjects design was used with four conditions; three consolidation-interference tasks (a visuospatial and two verbal interference tasks) and a no-task control condition. Forty-one participants listened to a soundtrack depicting traumatic scenes (e.g., police brutality, torture and rape). Immediately after listening to the soundtrack, the subjects completed a randomly assigned task for 10 min. Intrusions from the soundtrack were reported in a diary during the following seven-day period.

RESULTS

In line with a modality-specific approach to intrusion modulation, auditory intrusions were reduced by verbal tasks compared to both a no-task and a visuospatial interference task..

LIMITATIONS

The study did not control for individual differences in imagery ability which may be a feature in intrusion development.

CONCLUSIONS

The results provide an increased understanding of how intrusive mental images can be modulated which may have implications for preventive treatment..

Decreased reaction time variability is associated with greater cardiovascular responses to acute stress

Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75‐min recovery. RT measures were generated from an ex‐Gaussian distribution that yielded three predictors: mu‐RT, sigma‐RT, and tau‐RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = −.009, SE = .005, p = .09) and diastolic (B = −.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = −.007, SE = .003, p = .03) and impaired vagal tone (B = −.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses.

Social-Biological Interactions in Oral Disease: A 'Cells to Society' View

Oral diseases constitute a major worldwide public health problem, with their burden concentrating in socially disadvantaged and less affluent groups of the population, resulting in significant oral health inequalities. Biomedical and behavioural approaches have proven relatively ineffective in reducing these inequalities, and have potentially increased the health gap between social groups. Some suggest this stems from a lack of understanding of how the social and psychosocial contexts in which behavioural and biological changes occur influence oral disease. To unravel the pathways through which social factors affect oral health outcomes, a better understanding is thus needed of how the social 'gets under the skin,' or becomes embodied, to alter the biological. In this paper, we present the current knowledge on the interplay between social and biological factors in oral disease. We first provide an overview of the process of embodiment in chronic disease and then evaluate the evidence on embodiment in oral disease by reviewing published studies in this area. Results show that, in periodontal disease, income, education and perceived stress are correlated with elevated levels of stress hormones, disrupted immune biomarkers and increased allostatic load. Similarly, socioeconomic position and increased financial stress are related to increased stress hormones and cariogenic bacterial counts in dental caries. Based on these results, we propose a dynamic model depicting social-biological interactions that illustrates potential interdependencies between social and biological factors that lead to poor oral health. This work and the proposed model may aid in developing a better understanding of the causes of oral health inequalities and implicate the importance of addressing the social determinants of oral health in innovating public health interventions.

Blunted cardiac reactivity to psychological stress associated with higher trait anxiety: a study in peacekeepers

Background

Both exaggerated and diminished reactivity to stress can be maladaptive. Previous studies have shown that performing increasingly difficult tasks leads first to increased reactivity and then to a blunted response when success is impossible. Our aim was to investigate the influence of trait anxiety on cardiac and cortisol response to and recovery from a standardized psychosocial stress task (Trier Social Stress Task) in a homogeneous sample of healthy peacekeepers. We hypothesized that participants with higher trait anxiety would show blunted reactivity during the performance of an overwhelmingly difficult and stressful task. Participants (N = 50) delivered a speech and performed an arithmetic task in the presence of critical evaluators. Cortisol samples and electrocardiogram data were collected. Participants completed the State-Trait Anxiety Inventory—Trait version, the Posttraumatic Stress Disorder Checklist—Civilian Version (PCL-C) and the Military Peace Force Stressor Inventory.

Results

For heart rate, the findings showed that peacekeepers with higher trait anxiety reacted less to the speech task (p = 0.03) and to the arithmetic task (p = 0.008) than those with lower trait anxiety. Trait anxiety did not modulate cortisol responses to the task. Despite the high trait anxiety group having higher PCL-C scores than the low trait anxiety group (p < 0.0001), this did not influence the cardiac results.

Conclusions

We concluded that individuals with higher trait anxiety had less tachycardia in response to acute psychological stress than those with lower trait anxiety. The present results point to a higher risk for more anxious individuals of a maladaptive reaction to stressful events.

Does a 20-week aerobic exercise training programme increase our capabilities to buffer real-life stressors? A randomized, controlled trial using ambulatory assessment

PURPOSE

The cross-stressor adaptation hypothesis suggests that regular exercise leads to adaptations in the stress response systems that induce decreased physiological responses to psychological stressors. Even though an exercise intervention to buffer the detrimental effects of psychological stressors on health might be of utmost importance, empirical evidence is mixed. This may be explained by the use of cross-sectional designs and non-personally relevant stressors. Using a randomized controlled trial, we hypothesized that a 20-week aerobic exercise training does reduce physiological stress responses to psychological real-life stressors in sedentary students.

METHODS

Sixty-one students were randomized to either a control group or an exercise training group. The academic examination period (end of the semester) served as a real-life stressor. We used ambulatory assessment methods to assess physiological stress reactivity of the autonomic nervous system (heart rate variability: LF/HF, RMSSD), physical activity and perceived stress during 2 days of everyday life and multilevel models for data analyses. Aerobic capacity (VO2max) was assessed pre- and post-intervention via cardiopulmonary exercise testing to analyze the effectiveness of the intervention.

RESULTS

During real-life stressors, the exercise training group showed significantly reduced LF/HF (β = -0.15, t = -2.59, p = .01) and increased RMSSD (β = 0.15, t = 2.34, p = .02) compared to the control group.

CONCLUSIONS

Using a randomized controlled trial and a real-life stressor, we could show that exercise appears to be a useful preventive strategy to buffer the effects of stress on the autonomic nervous system, which might result into detrimental health outcomes.

Burnout Is Associated with Reduced Parasympathetic Activity and Reduced HPA Axis Responsiveness, Predominantly in Males

There is mounting evidence that burnout is a risk factor for cardiovascular disease (CVD). Stress-related dysregulation of the sympathetic and parasympathetic system and the hypothalamic pituitary adrenal (HPA) axis may explain the enhanced risk for CVD. To test this hypothesis, 55 patients (34 males and 21 females) with burnout on sickness absence and 40 healthy participants (16 males and 24 females) were exposed to a psychosocial stressor consisting of mental arithmetic and public speech. Physiological variables (i.e., blood pressure, heart rate, cardiac output, vascular resistance, cortisol, and alpha-amylase) were measured. Basal levels, reactivity, and recovery were compared between groups. In male patients, baseline systolic blood pressure was higher, whereas basal alpha-amylase and cortisol reactivity were lower than in healthy males. In female patients, a tendency for lower basal cortisol was found as compared to healthy females. Furthermore, reduced basal heart rate variability and a trend for elevated basal cardiac output were observed in both male and female patients. Burnout is characterised by dysregulation of the sympathetic and parasympathetic system and the HPA axis, which was more pronounced in males than in females. This study further supports burnout as being a risk factor for CVD through dysregulation of the sympathetic and parasympathetic system and the HPA axis.

Heritability and Temporal Stability of Ambulatory Autonomic Stress Reactivity in Unstructured 24-Hour Recordings

OBJECTIVE

Measurements of ambulatory autonomic reactivity can help with our understanding of the long-term health consequences of exposure to psychosocial stress in real-life settings.

METHODS

In this study, unstructured 24-hour ambulatory recordings of cardiac parasympathetic and sympathetic control were obtained in 1288 twins and siblings, spanning both work time and leisure time. These data were used to define two ambulatory baseline (sleep, leisure) and four stress conditions (wake, work, work_sitting, work_peak) from which six ambulatory stress reactivity measures were derived. The use of twin families allowed for estimation of heritability and testing for the amplification of existing or emergence of new genetic variance during stress compared with baseline conditions.

RESULTS

Temporal stability of ambulatory reactivity was assessed in 62 participants and was moderate to high over a 3-year period (0.36 < r < 0.91). Depending on the definition of ambulatory reactivity used, significant heritability was found, ranging from 29% to 40% for heart rate, 34% to 47% for cardiac parasympathetic control (indexed as respiratory sinus arrhythmia), and 10% to 19% for cardiac sympathetic control (indexed as the preejection period). Heritability of ambulatory reactivity was largely due to newly emerging genetic variance during stress compared with periods of rest. Interestingly, reactivity to short standardized stressors was poorly correlated with the ambulatory reactivity measures implying poor laboratory-real-life correspondence.

CONCLUSIONS

Ambulatory autonomic reactivity extracted from an unstructured real-life setting shows reliable, stable, and heritable individual differences. Real-life situations uncover a new and different genetic variation compared with that seen in resting baseline conditions, including sleep.

Sympathoneural and adrenomedullary responses to mental stress

This concept-based review provides historical perspectives and updates about sympathetic noradrenergic and sympathetic adrenergic responses to mental stress. The topic of this review has incited perennial debate, because of disagreements over definitions, controversial inferences, and limited availability of relevant measurement tools. The discussion begins appropriately with Cannon's "homeostasis" and his pioneering work in the area. This is followed by mental stress as a scientific idea and the relatively new notions of allostasis and allostatic load. Experimental models of mental stress in rodents and humans are discussed, with particular attention to ethical constraints in humans. Sections follow on sympathoneural responses to mental stress, reactivity of catecholamine systems, clinical pathophysiologic states, and the cardiovascular reactivity hypothesis. Future advancement of the field will require integrative approaches and coordinated efforts between physiologists and psychologists on this interdisciplinary topic.

Resting Plasma Lipids and Cardiovascular Reactivity to Acute Psychological Stress

Abstract. Prior research suggests that hyperlipidemia is associated with elevated blood pressure responses to acute stress but whether lipid levels influence underlying cardiac and vascular determinants of blood pressure during stress is not known. Thus, we examined whether lipids were associated with stress-induced blood pressure responses and responses of stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR). In 19 healthy university students (15 men), blood was drawn to measure lipid levels (triglycerides, low-density lipoprotein cholesterol [LDL-c], high-density lipoprotein cholesterol [HDL-c], total cholesterol) after a 10-min rest period. Participants then completed a 6-min mental arithmetic stressor and a 3-min cold pressor (separated by a 10-min recovery). This procedure was repeated twice, approximately 6 weeks apart. Lipids and hemodynamic values were averaged across the two sessions. Multiple linear regression analyses revealed that a model including LDL-c, HDL-c, and triglycerides significantly predicted diastolic blood pressure (DBP), R2adj = .45, p = .007, and systolic blood pressure (SBP) cold pressor reactivity, R2adj = .35, p = .023. Individually, only LDL-c significantly predicted DBP, β = .64, p = .003, and SBP cold pressor reactivity, β = .64, p = .005. The same model marginally predicted CO, R2adj = .24, p = .069, and TPR, R2adj = 21, p = .091, reactivity to mental arithmetic, but only triglycerides were independently associated with CO, β = −.63, p = .012, and TPR, β = .54, p = .029 reactivity. Lipids were not associated with heart rate (HR) or SV reactivity. LDL-c was positively associated with the blood pressure response to the cold pressor, whereas triglycerides were positively and negatively associated with the TPR and CO responses, respectively, to mental arithmetic. Endothelial dysfunction and greater release of vasoconstrictors in those with high lipids may explain these relationships.

The Association between Neuroticism and Heart Rate Variability Is Not Fully Explained by Cardiovascular Disease and Depression

Neuroticism is associated with cardiovascular disease, autonomic reactivity, and depression. Here we address the extent to which neuroticism accounts for the excess heart disease risk associated with depression and test whether cardiac autonomic tone plays a role as mediator. Subjects were derived from a nationally representative sample (n = 1,255: mean age 54.5, SD = 11.5). Higher neuroticism was associated with reduced heart rate variability equally under rest and stress. The baseline structural equation model revealed significant paths from neuroticism to heart rate variability, cardiovascular disease and depression, and between depression and cardiovascular disease, controlling for age, sex, height, weight, and BMI. Dropping both the neuroticism to heart rate variability, and neuroticism to heart disease paths significantly reduced the model fit (p < .001 in each case). We conclude that neuroticism has independent associations with both autonomic reactivity and cardiovascular disease, over and above its associations with depression and other related variables.

Sympathetic reactivity in young women with a family history of hypertension

Young adults with a family history of hypertension (+FH) have increased risk of developing hypertension. Furthermore, the blood pressure (BP) response to sympathoexcitatory stimuli in young adults can predict the future development of hypertension. Therefore, we hypothesized young women with a +FH would have exaggerated cardiovascular and sympathetic reactivity compared with young women without a family history of hypertension (-FH). Beat-by-beat mean arterial pressure (MAP) and muscle sympathetic nerve activity (MSNA) were measured in 14 women +FH (22 ± 1 yr, 21 ± 1 kg/m(2), MAP 80 ± 2 mmHg) and 15 women -FH (22 ± 1 yr, 22 ± 1 kg/m(2), MAP 78 ± 2 mmHg) during acute sympathoexcitatory maneuvers: cold pressor test, 2 min of isometric handgrip (HG) exercise at 30% of maximal voluntary contraction, and 3 min of postexercise ischemia (PEI; isolated activation of the skeletal muscle metaboreflex). During cold pressor test, the increase in BP was greater in women +FH (ΔMAP: +FH 16 ± 2 vs. -FH 11 ± 1 mmHg, P < 0.05), which was accompanied by an exaggerated increase in MSNA (ΔMSNA: +FH 17 ± 2 vs. -FH 8 ± 2 burst/min, P < 0.05). The increase in BP was greater in +FH during the last minute of HG (ΔMAP: +FH 23 ± 3 vs. -FH 12 ± 1 mmHg, P < 0.05) and during PEI (ΔMAP: +FH 17 ± 3 vs. -FH 9 ± 2 mmHg, P < 0.05). Similarly, the increase in MSNA was greater in +FH during both HG (ΔMSNA: +FH 12 ± 2 vs. -FH 6 ± 2 burst/min, P < 0.05) and PEI (ΔMSNA: +FH 16 ± 2 vs. -FH 4 ± 2 burst/min, P < 0.05). These data demonstrate that +FH women have greater BP and sympathetic reactivity compared with -FH women.

School burnout: increased sympathetic vasomotor tone and attenuated ambulatory diurnal blood pressure variability in young adult women

Two studies examined autonomic and cardiovascular functioning that may link school burnout to cardiovascular risk factors in young healthy adult females. Study 1 (N = 136) investigated whether school burnout was related to resting values of blood pressure (BP) and blood pressure variability (BPV) through laboratory beat-to-beat BP assessment. Study 2 (N = 94) examined the link between school burnout and diurnal BPV through ambulatory BP monitoring. Controlling for anxiety and depressive symptomatology, school burnout demonstrated strong positive relationships with indices of cardiac sympathovagal tone, sympathetic vasomotor tone, inefficient myocardial oxygen consumption, increased 24-h ambulatory heart rate and BP, blunted BP diurnal variability, and increased arterial stiffness. These studies establish cardiovascular biomarkers of school burnout and suggest that even in a seemingly healthy sample school burnout may predispose females to increased cardiovascular risk. Several future lines of research are outlined.

An explorative study of metabolic responses to mental stress and yoga practices in yoga practitioners, non-yoga practitioners and individuals with metabolic syndrome

BACKGROUND

Stress places a metabolic burden on homeostasis and is linked to heightened sympathetic activity, increased energy expenditure and pathology. The yogic state is a hypometabolic state that corresponds with mind-body coherence and reduced stress. This study aimed to investigate metabolic responses to stress and different yoga practices in regular yoga practitioners (YP), non-yoga practitioners (NY) and metabolic syndrome patients (MS).

METHODS

YP (n = 16), NY (n = 15) and MS (n = 15) subjects underwent an experimental protocol that comprised of different 5-minute interventions including mental arithmetic stress test (MAST), alternate nostril breathing (ANB), Kapabhati breathing (KB) and meditation (Med) interspersed with 5 minutes of quiet resting (neutral condition (NC)). During the intervention periods continuous body weight adjusted oxygen consumption (VO2ml/min/kg) was measured using open circuit indirect calorimetry with a canopy hood.

RESULTS

This is the first study to report oxygen consumption (OC) in yoga practitioners during and after MAST and the first to report both within and between different populations. The results were analysed with SPSS 16 using 3X9 mixed factorial ANOVAs. The single between-subject factor was group (YP, NY and MS), the single within-subject factor was made up of the nine intervention phases (NC1, MAST, NC2, ANB, NC3, KB, NC4, Med, NC5). The results demonstrated that the regular YP group had significantly less OC and greater variability in their OC across all phases compared to the MS group (p = .003) and NY group (p = .01). All groups significantly raised their OC during the mental arithmetic stress, however the MS group had a significantly blunted post-stress recovery whereas the YP group rapidly recovered back to baseline levels with post stress recovery being greater than either the NY group or MS group.

CONCLUSIONS

Yoga practitioners have greater metabolic variability compared to non-yoga practitioners and metabolic syndrome patients with reduced oxygen requirements during resting conditions and more rapid post-stress recovery. OC in metabolic syndrome patients displays significantly blunted post-stress recovery demonstrating reduced metabolic resilience. Our results support the findings of previous randomised trials that suggest regular yoga practice may mitigate against the effects of metabolic syndrome.

CLINICAL TRIAL NUMBER

ACTRN12614001075673; Date of Registration: 07/10/2014.

Increased systolic blood pressure reactivity to acute stress is related with better self-reported health

The stress reactivity hypothesis posits that the magnitude of cardiovascular reactions to acute stress tasks is related with future blood pressure status, heart hypertrophy, and atherosclerosis. We assessed the stress reactivity hypothesis and aimed to identify which physiological indices (blood pressure, heart-rate, cortisol, salivary immunoglobulin A (sIgA)) related to self-reported mental and physical health. We also assessed if physiological reactions elicited by an acute stressor were more related than basal assessments. Participants provided physiological samples, self-reported stress and health-data before and after an assessed 5–7 minute academic oral presentation. In hierarchical regression models, increased systolic and reduced sIgA reactivity was associated with better perceptions of mental health. Reactivity data were more related to self-reported data than basal data. In line with the only 2 studies to assess the reactivity hypothesis with self-perceived health, increased systolic reactivity was best associated with better perceived physical and mental health. The findings suggest that increased SBP reactivity may also be associated with positive health outcomes. Further research is required to determine if increased or decreased sIgA reactivity is most predictive of future morbidity.

Randomised controlled trial of a 12 week yoga intervention on negative affective states, cardiovascular and cognitive function in post-cardiac rehabilitation patients

BACKGROUND

Negative affective states such as anxiety, depression and stress are significant risk factors for cardiovascular disease, particularly in cardiac and post-cardiac rehabilitation populations.Yoga is a balanced practice of physical exercise, breathing control and meditation that can reduce psychosocial symptoms as well as improve cardiovascular and cognitive function. It has the potential to positively affect multiple disease pathways and may prove to be a practical adjunct to cardiac rehabilitation in further reducing cardiac risk factors as well as improving self-efficacy and post-cardiac rehabilitation adherence to healthy lifestyle behaviours.

METHOD AND DESIGN

This is a parallel arm, multi-centre, randomised controlled trial that will assess the outcomes of post- phase 2 cardiac rehabilitation patients assigned to a yoga intervention in comparison to a no-treatment wait-list control group. Participants randomised to the yoga group will engage in a 12 week yoga program comprising of two group based sessions and one self-administered home session each week. Group based sessions will be led by an experienced yoga instructor. This will involve teaching beginner students a hatha yoga sequence that incorporates asana (poses and postures), pranayama (breathing control) and meditation. The primary outcomes of this study are negative affective states of anxiety, depression and stress assessed using the Depression Anxiety Stress Scale. Secondary outcomes include measures of quality of life, and cardiovascular and cognitive function. The cardiovascular outcomes will include blood pressure, heart rate, heart rate variability, pulse wave velocity, carotid intima media thickness measurements, lipid/glucose profiles and C-reactive protein assays. Assessments will be conducted prior to (week 0), mid-way through (week 6) and following the intervention period (week 12) as well as at a four week follow-up (week 16).

DISCUSSION

This study will determine the effect of yoga practice on negative affective states, cardiovascular and cognitive function in post-phase 2 cardiac rehabilitation patients. The findings may provide evidence to incorporate yoga into standardised cardiac rehabilitation programs as a practical adjunct to improve the management of psychosocial symptoms associated with cardiovascular events in addition to improving patients' cognitive and cardiovascular functions.

TRIAL REGISTRATION

ACTRN12612000358842.

Study of cardiovascular reactivity to mental stress in different phases of menstrual cycle

BACKGROUND

It is a well known fact that normally female sex hormone levels fluctuate during the menstrual cycle. The presence of receptors for these hormones on both heart and blood vessels may also hint at variations in physiological functions during menstrual cycle. So this study was an attempt to determine whether the follicular and luteal phases of menstrual cycle are characterized by variations in cardiovascular parameters in the resting state and also examine changes in cardiovascular reactivity to mental stress challenge during both the phases of menstrual cycle.

METHODOLOGY

Thirty healthy females in the age group of 18-25 years with regular menstrual cycles fulfilling the inclusion criteria were examined for cardiovascular parameters (heart rate and blood pressures) at rest and their reactivity to mental stress during the follicular and luteal phase and were compared by using paired t-test. A p-value of <0.05 was considered as statistically significant.

RESULTS

The women included in the study produced the well known reactivity to mental stress, in terms of blood pressure and heart rate increases, but the two phases of menstrual cycle were indistinguishable in so far as reactivity patterns were considered. The resting values of these cardiovascular parameters were also alike during the two phases.

CONCLUSION

We were unable to unearth any differences in resting and reactivity values of cardiovascular parameters during the course of a normal menstrual cycle. This shows that stress reactivity variations during different phases of menstrual cycle may not be due to variations in hormonal levels per se, but due to collusion of hormonal variations and unknown genetic influences.

Does unconscious stress play a role in prolonged cardiovascular stress recovery?

According to recent insights, humans might not be aware of a substantial part of their cognitive stress representations while these still have prolonged physiological effects. 'Unconscious stress' can be measured by implicit affect (IA) tests. It was shown that IA predicts physiological stress responses, in fact better than explicit ('conscious') affect. It is not known yet whether IA is associated with concurrent prolonged stress responses. In two studies (n = 62 and 123), anger harassment was used to induce stress. Blood pressure (BP) and heart rate (HR) were measured continuously. During BP and HR recovery, IA was measured by an 'anger' version of the implicit association test (IAT) or the implicit positive and negative affect test (IPANAT). Blood pressure and HR increased during anger harassment and recovery afterwards. When using the IPANAT BP recovery levels were lower when positive IA was high and higher when negative IA was high, independent of explicit affect and rumination. These results were not found using the IAT. These results provide preliminary evidence that physiological stress recovery is associated with IA. This is in line with the theory that unconscious stress is responsible for a-possibly considerable-part of unhealthy prolonged stress-related physiological activity.

Stress task specific impairments of cardiovascular functioning in obese participants

The role that excess adipose tissue plays in chronic inflammation gives rise to its importance as an independent risk factor in cardiovascular dysfunction. Operationalizing chronic stress as obesity, we sought to explore the relationship between obesity, perceived stress and cardiovascular reactivity and recovery from laboratory stressors. Cardiovascular function was assessed using blood pressure and heart rate. Two stress tasks (mental arithmetic and cold pressor) were employed to examine potential differences between type of stress and cardiovascular response. Body mass index (BMI) was able to predict dysfunction in both cardiovascular reactivity and recovery. Participants with a higher BMI exhibited blunted systolic blood pressure and heart rate reactivity to the mental arithmetic task. In contrast, BMI has an incongruent effect on blood pressure reactivity to the cold pressor task that is dependent on the level of perceived stress. This suggests that in some instances the effect of BMI on cardiovascular response to acute stress may be moderated by perceived stress. Further, we found greater adiposity was related to delayed heart rate recovery following both stress tasks.

GENDER SPECIFICS OF STRUCTURAL AND FUNCTIONAL PARAMETERS OF VESSELS IN RELATION TO PSYCHOEMOTIONAL FACTORS IN ALMOST HEALTHY INDIVIDUALS

Aim.To study gender specifics of structural and functional parameters of brachiocephal arteries with the relation to psychoemotional factors in almost healthy individuals.

Material and Methods.Overall 107 almost healthy economically active individuals included from organized population (46 male, 61 female), with the average age 43,4±10,8 y. All participants underwent psychological testing that included questionnaires: Spolberger-Khanin test, depression evaluation scale by the Center for Epidemiological Studies, visualanalogue scale (modified Dembo-Rubinstein), the social frustration level, social adaptation test by Holmes-Rey, ultrasound scanning of brachiocephal arteries with evaluation of local rigidity parameters.

Results.There were significant gender differences found for the vessel wall structural and functional parameters. Average values of systolic and diastolic diameters, total common carotid artery wall thickness were higher in males, but the rigidity index - in women. Prevalence of personal anxiety and clinically significant stress estimates by the Holmes-Rey scale was significantly higher in women, 75% and 36%, resp. In both groups the association of psycho-emotional factors and vessel parameters was found. But for men there was independent relation of reactive and personal anxiety with the thickness of “intima-media” and in women – correlation of depression and vessel wall compliance.

Conclusion.The results direct to the need for further research of novel methods for complex primary prophylaxy of stress-induced remodeling of vessels with the connection to psychoemotional and gender specifics.

A brief review and clinical application of heart rate variability biofeedback in sports, exercise, and rehabilitation medicine

CONTEXT

An important component of the effective management of chronic noncommunicable disease is the assessment and management of psychosocial stress. The measurement and modulation of heart rate variability (HRV) may be valuable in this regard.

OBJECTIVE

To describe the measurement and physiological control of HRV; to describe the impact of psychosocial stress on cardiovascular disease, metabolic syndrome, and chronic respiratory disease, and the relationship between these diseases and changes in HRV; and to describe the influence of biofeedback and exercise on HRV and the use of HRV biofeedback in the management of chronic disease.

DATA SOURCES AND STUDY SELECTION

The PubMed, Medline, and Embase databases were searched (up to August 2013). Additional articles were obtained from the reference lists of relevant articles and reviews. Articles were individually selected for further review based on the quality and focus of the study, and the population studied.

RESULTS

Heart rate variability is reduced in stress and in many chronic diseases, and may even predict the development and prognosis of some diseases. Heart rate variability can be increased with both exercise and biofeedback. Although the research on the effect of exercise is conflicting, there is evidence that aerobic training may increase HRV and cardiac vagal tone both in healthy individuals and in patients with disease. Heart rate variability biofeedback is also an effective method of increasing HRV and cardiac vagal tone, and has been shown to decrease stress and reduce the morbidity and mortality of disease.

CONCLUSION

The assessment and management of psychosocial stress is a challenging but important component of effective comprehensive lifestyle interventions for the management of noncommunicable disease. It is, therefore, important for the sports and exercise physician to have an understanding of the therapeutic use of HRV modulation, both in the reduction of stress and in the management of chronic disease.

Does cardiac reactivity in the laboratory predict ambulatory heart rate? Baseline counts

Cardiovascular reactivity to laboratory stress might predict cardiovascular load in everyday life. However, previous research throws doubt on this hypothesis. This study examined associations between heart rate (HR) to a public speaking task and ambulatory HR throughout a day. Electrocardiogram, bodily movement, and psychosocial variables (affect, context) were recorded in 111 individuals. Ambulatory HR was positively associated with both positive and negative affect. Baseline HR in the laboratory significantly predicted ambulatory HR, but HR reactivity did not. The interaction of momentary negative affect and cardiac reactivity in the laboratory was also not significant. However, a significant interaction of baseline HR and reactivity indicated that, when baseline was high, there was a positive relation between HR reactivity and ambulatory HR. Findings suggest that baseline has to be considered when aiming to predict cardiovascular load in everyday life.

Assessing treatments used to reduce rumination and/or worry: a systematic review

Perseverative cognitions such as rumination and worry are key components of mental illnesses such as depression and anxiety. Given the frequent comorbidity of conditions in which rumination and worry are present, it is possible that they are underpinned by the same cognitive process. Furthermore, rumination and worry appear to be part of a causal chain that can lead to long-term health consequences, including cardiovascular disease and other chronic conditions. It is important therefore to understand what interventions may be useful in reducing their incidence. This systematic review aimed to assess treatments used to reduce worry and/or rumination. As we were interested in understanding the current treatment landscape, we limited our search from 2002 to 2012. Nineteen studies were included in the review and were assessed for methodological quality and treatment integrity. Results suggested that mindfulness-based and cognitive behavioural interventions may be effective in the reduction of both rumination and worry; with both Internet-delivered and face-to-face delivered formats useful. More broadly, it appears that treatments in which participants are encouraged to change their thinking style, or to disengage from emotional response to rumination and/or worry (e.g., through mindful techniques), could be helpful. Implications for treatment and avenues for future research are discussed.

Self-reported racial discrimination and endothelial reactivity to acute stress in women

This study investigated the effect of self-reported racial discrimination on endothelial responses to acute laboratory mental stress among post-menopausal women. One-hundred thirteen women (n = 94 self-identified as White and n = 19 self-identified as racial/ethnic minority), 43% with type 2 diabetes, reported lifetime experiences of racial/ethnic discrimination. Repeated assessments of flow-mediated dilation were performed at baseline, immediately after 5 min of mental arithmetic and at 20-min recovery. Both White and racial/ethnic minority women reported lifetime discrimination, with rates significantly higher among minorities. Self-reported lifetime discrimination was associated with attenuated flow-mediated dilation at recovery. Confounding variables, including clinical characteristics, mood, personality traits, other life stressors and general distress, did not better account for the effect of racial discrimination. Neither race/ethnicity nor diabetes status moderated the effect. The perceived stressfulness of the mental arithmetic was not associated with the endothelial response. In conclusion, self-reported lifetime discrimination is associated with attenuated endothelial recovery from acute mental stress. Elucidating the effects of discrimination and the biological mechanisms through which it affects the vasculature may suggest interventions to improve health.

Augmented limb blood flow during neurovascular stress in physically fit women

The study examined whether cardiorespiratory fitness modifies cardiovascular responses by normotensive men and women during the Stroop color-word interference test. Independent of age and an estimate of body fatness, fitness level was positively related (R²  = .39 and .51) to increases in limb blood flow and vascular conductance, coherent with cardiac-vagal withdrawal and a decrease in heart period, among women but not men. Fitness was unrelated to changes in systolic and diastolic blood pressures and muscle sympathetic nerve activity. The augmented hemodynamic responses among fitter women were not consistent with passive vasodilation via withdrawal of sympathetic neural tone. The results encourage further gender comparisons testing whether fitness augments limb blood flow during mental stress by neurohumoral and flow-mediated vasodilatory mechanisms or by increased cardiac output.

Genetic influence on blood pressure and underlying hemodynamics measured at rest and during stress

OBJECTIVE

This study examined the genetic and environmental contributions to the individual differences in blood pressure (BP) levels and underlying hemodynamic characteristics at rest and during mental challenge tasks in a large twin cohort of youth. Including both European American and African American twins further allowed examination of potential ethnic differences.

METHODS

We studied cardiovascular reactivity to two stressors (car-driving simulation and a social stressor interview) in 308 European American and 223 African American twin pairs including monozygotic twin pairs and same-sex as well as opposite-sex dizygotic twin pairs (mean [standard deviation] age = 14.7 [3.1]). Variables included systolic and diastolic BP, heart rate, stroke volume, cardiac output, and total peripheral resistance.

RESULTS

Heritability indices for levels at rest and during stress were high (31%-73%) and comparable between ethnic groups. A common genetic factor accounted for both resting and stress levels explaining 23% to 58% of the total variance. The increases in heritability indices for BP and heart rate from rest to stress are mostly explained by newly emerging genetic influences on the added stress component. Indices for hemodynamic variables remained stable from rest to stress owing to a simultaneous decrease in genetic and environmental variances.

CONCLUSIONS

Cardiovascular measures obtained during rest and stress show substantial heritability that is comparable between individuals of African and European descent. Most of the variance in both resting and stress levels is explained by common genetic factors, although other genetic factors that only contribute to cardiovascular levels during stress are also important.

Assessing the global burden of ischemic heart disease, part 2: analytic methods and estimates of the global epidemiology of ischemic heart disease in 2010

BACKGROUND

Ischemic Heart Disease (IHD) is the leading cause of death worldwide. The Global Burden of Diseases, Injuries and Risk Factors (GBD) 2010 Study estimated IHD mortality and disability burden for 21 world regions for the years 1990 to 2010.

METHODS

Data sources for GBD IHD epidemiology estimates were mortality surveillance, verbal autopsy, and vital registration data (for IHD mortality) and systematic review of IHD epidemiology literature published 1980-2008 (for non-fatal IHD outcomes). An estimation and validation process led to an ensemble model of IHD mortality by country for all 21 world regions, adjusted for country-level covariates. Disease models were developed for the nonfatal sequelae of IHD: myocardial infarction, stable angina pectoris, and ischemic heart failure.

RESULTS

Country level covariates including metabolic and nutritional risk factors, education, war, and annual income per capita contributed to the ensemble model for the analysis of IHD death. In the acute myocardial infarction model, inclusion of troponin in the diagnostic criteria of studies published after the year 2000 was associated with a 50% higher incidence. Self-reported diagnosis of angina significantly overestimated stable angina prevalence compared with "definite" angina elicited by the Rose angina questionnaire. For 2010, Eastern Europe and Central Asia had the highest rates of IHD death and the Asia Pacific High-Income, East Asia, Latin American Andean, and sub-Saharan Africa regions had the lowest.

CONCLUSIONS

Global and regional IHD epidemiology estimates are needed for estimating the worldwide burden of IHD. Using descriptive meta-analysis tools, the GBD 2010 standardized and pooled international data by adjusting for region-level mortality and risk factor data, and study level diagnostic method. Analyses maximized internal consistency, generalizability, and adjustment for known sources of bias. The GBD IHD analysis nonetheless highlights the need for improved IHD epidemiology surveillance in many regions and the need for uniform diagnostic standards.

How neighborhood disorder increases blood pressure in youth: agonistic striving and subordination

Growing evidence links perceptions of neighborhood disorder to adverse health outcomes but little is known about psychological processes that may mediate this association. We tested the hypothesis that two psychological mechanisms-agonistic striving and subordination-mediate the link between perceived neighborhood disorder and hypertension risk in youth. Perceived neighborhood disorder, agonistic striving, subordination experiences, negative affect, obesity, and ambulatory blood pressure during daily activities (48 h) were assessed in a multiethnic sample of 167 low- to middle-income urban adolescents. Path analyses revealed that agonistic striving, subordination, and obesity each independently mediated the association between neighborhood disorder and blood pressure; these variables accounted for 73 % of the shared variance, 42 % of which was explained by agonistic striving. The direct relationship between perceived neighborhood disorder and blood pressure was no longer significant in the presence of these mediators. Negative affect was associated with neighborhood disorder and subordination, but not blood pressure. Agonistic striving proved to be a significant and substantial mediator of the association between perceived neighborhood disorder, blood pressure, and future hypertension risk. New research should seek to clarify the processes by which stressful neighborhoods induce persistent agonistic motives and perceptions of subordination in adolescents.

Mathematical modeling the neuroregulation of blood pressure using a cognitive top-down approach

Background:

The body′s physiological stability is maintained by the influence of the autonomic nervous system upon the dynamic interaction of multiple systems. These physiological systems, their nature and structure, and the factors which influence their function have been poorly defined. A greater understanding of such physiological systems leads to an understanding of the synchronised function of organs in each neural network i.e. there is a fundamental relationship involving sensory input and/or sense perception, neural function and neural networks, and cellular and molecular biology. Such an approach compares with the bottom-up systems biology approach in which there may be an almost infinite degree of biochemical complexity to be taken into account.

Aims:

The purpose of this article is to discuss a novel cognitive, top-down, mathematical model of the physiological systems, in particular its application to the neuroregulation of blood pressure.

Results:

This article highlights the influence of sensori-visual input upon the function of the autonomic nervous system and the coherent function of the various organ networks i.e. the relationship which exists between visual perception and pathology.

Conclusions:

The application of Grakov′s model may lead to a greater understanding of the fundamental role played by light e.g. regulating acidity, levels of Magnesium, activation of enzymes, and the various factors which contribute to the regulation of blood pressure. It indicates that the body′s regulation of blood pressure does not reside in any one neural or visceral component but instead is a measure of the brain′s best efforts to maintain its physiological stability.

Phosphorylated nerve growth factor-induced clone B (NGFI-B) translocates from the nucleus to mitochondria of stressed rat cardiomyocytes and induces apoptosis

Stress induces cardiac dysfunction and cardiomyocyte injury, and while current data indicate that mitochondria play a key role in this process, the mechanisms remain unknown. In this study, we found that in rats, restraint stress induced nerve growth factor-induced clone B (NGFI-B) translocation from the nucleus to mitochondria in cardiomyocytes. This translocation promoted cytochrome c release from mitochondria to the cytoplasm, which ultimately resulted in cardiomyocyte apoptosis. We also found that stress induced oversecretion of glucocorticoids and activated the protein kinase A (PKA) pathway in cardiomyocytes. Enhanced PKA activity increased NGFI-B serine phosphorylation, which caused NGFI-B to translocate from the nucleus to mitochondria. Moreover, a PKA peptide inhibitor blocked NGFI-B serine phosphorylation and translocation. Our data demonstrate that stress affects cardiomyocytes by inducing NGFI-B mitochondrial translocation via serine phosphorylation, which in turn initiates mitochondrial-mediated apoptosis.