Synergistic effects of psychological and immune stressors on inflammatory cytokine and sickness responses in humans.

Activation of the innate immune system is commonly accompanied by a set of behavioural, psychological and physiological changes known as 'sickness behaviour'. In animals, infection-related sickness symptoms are significantly increased by exposure to psychosocial stress, suggesting that psychological and immune stressors may operate through similar pathways to induce sickness. We used a double-blind, randomised, placebo-controlled design to examine the effect of acute psychological stress on immune and subjective mood responses to typhoid vaccination in 59 men. Volunteers were assigned to one of four experimental conditions in which they were either injected with typhoid vaccine or saline placebo, and then either rested or completed two challenging behavioural tasks. Typhoid vaccine induced a significant rise in participants' serum levels of interleukin-6 (IL-6) and this response was significantly larger in the stress versus rest conditions. Negative mood increased immediately post-tasks, an effect also more pronounced in the vaccine/stress condition. In the vaccine/stress group, participants with larger IL-6 responses had heightened systolic blood pressure responses to tasks and elevated post-stress salivary levels of the noradrenaline metabolite 3-methoxy-phenyl glycol (MHPG) and cortisol. Our findings suggest that, as seen in animals, psychological and immune stressors may act synergistically to promote inflammation and sickness behaviour in humans.

Cortisol awakening response is elevated in acute coronary syndrome patients with type-D personality.

OBJECTIVE: Type-D or "distressed" personality and depression following admission for acute coronary syndrome (ACS) have been associated with poor clinical outcome. The biological pathways underpinning this relationship may include disruption of the hypothalamic-pituitary-adrenocortical (HPA) axis. We therefore assessed cortisol output in patients who had recently suffered from ACS. METHOD: Salivary cortisol was assessed eight times over a 24-h period in 72 patients within 5 days of admission for ACS. Depressive symptoms were measured with the Beck Depression Inventory (BDI), and type-D personality was measured with the Type-D Scale-16. Particular attention was given to cortisol awakening response (CAR), which was measured as the difference in cortisol between waking and peak responses 15-30 min later. RESULTS: Cortisol showed a typical diurnal pattern, with low levels in the evening, high levels early in the day, and CAR averaging 7.58+/-10.0 nmol/l. Cortisol was not related to the severity of ACS or underlying coronary artery disease or to BDI scores. The CAR was positively associated with type-D personality independently of age, gender, and body mass (P=.007). Linear regression showed that type-D personality accounted for 7.9% of the variance in CAR after age, sex, body mass, BDI, cortisol level on waking, and fatigue had been taken into account (P=.008). CONCLUSIONS: Type-D personality may be associated with disruption of HPA axis function in survivors of acute cardiac events and may contribute to heightened inflammatory responses influencing future cardiac morbidity.

Hostility and physiological responses to laboratory stress in acute coronary syndrome patients.

OBJECTIVE: Evidence suggests that emotional stress can trigger acute coronary syndromes in patients with advanced coronary artery disease (CAD), although the mechanisms involved remain unclear. Hostility is associated with heightened reactivity to stress in healthy individuals, and with an elevated risk of adverse cardiac events in CAD patients. This study set out to test whether hostile individuals with advanced CAD were also more stress responsive. METHODS: Thirty-four men (aged 55.9+/-9.3 years) who had recently survived an acute coronary syndrome took part in laboratory testing. Trait hostility was assessed by the Cook Medley Hostility Scale, and cardiovascular activity, salivary cortisol, and plasma concentrations of interleukin-6 were assessed at baseline, during performance of two mental tasks, and during a 2-h recovery. RESULTS: Participants with higher hostility scores had heightened systolic and diastolic blood pressure (BP) reactivity to tasks (both P<.05), as well as a more sustained increase in systolic BP at 2 h post-task (P=.024), independent of age, BMI, smoking status, medication, and baseline BP. Hostility was also associated with elevated plasma interleukin-6 (IL-6) levels at 75 min (P=.023) and 2 h (P=.016) poststress and was negatively correlated with salivary cortisol at 75 min (P=.034). CONCLUSION: Hostile individuals with advanced cardiovascular disease may be particularly susceptible to stress-induced increases in sympathetic activity and inflammation. These mechanisms may contribute to an elevated risk of emotionally triggered cardiac events in such patients.