Chronic stress and regulation of cellular markers of inflammation in rheumatoid arthritis: implications for fatigue

Exploratory analysis of the relationships between aerobic capacity and self-reported fatigue in patients with rheumatoid arthritis, polymyositis, and chronic fatigue syndrome

OBJECTIVE

To determine if self-reported levels of physical activity and fatigue are related to peak oxygen uptake (VO(2peak)) and whether these relationships differ among the patient groups (rheumatoid arthritis [RA], polymyositis [PM], and chronic fatigue syndrome [CFS]).

DESIGN

Correlational investigation.

SETTING

Two ambulatory research clinics at the National Institutes of Health, Clinical Center, Bethesda, MD.

PARTICIPANTS

There were 9 patients with PM, 10 with RA, and 10 with CFS. All patients met case criteria for their respective diagnoses. METHODS/MAIN OUTCOME MEASUREMENTS: VO(2peak) during bicycle ergometry and self-reported fatigability, fatigue, and physical activity. VO(2peak) was used as the criterion measurement of physiological fatigue with which the self-reported variables were compared.

RESULTS

The Pearson r revealed that self-reported physical activity correlated with VO(2peak) (r = 61, P = .01). However, fatigability and fatigue did not correlate with VO(2peak). Linear regression analysis was performed to assess the effects of diagnosis group, self-reported activity level or fatigue, and their interaction. A trend in the data showed a distinctive relationship between fatigue/fatigability within the 3 groups. In addition, when controlling for group status, self-reported activity predicted aerobic capacity as measured by VO(2peak).

CONCLUSIONS

This study confirms that patients with chronic, but stable RA, PM, or CFS are fatigued and have significantly decreased aerobic capacity. Self-reports of physical activity predicted VO(2peak), and may be used as an indicator of activity-based aerobic capacity. Self-reports of fatigue, however, did not correlate with VO(2peak) and hence are assessing something other than an index of aerobic capacity, and provide additional information about patients' perceptions, which will require further investigation.

Social-evaluative threat and proinflammatory cytokine regulation: an experimental laboratory investigation

This study experimentally tested whether a stressor characterized by social-evaluative threat (SET), a context in which the self can be judged negatively by others, would elicit increases in proinflammatory cytokine activity and alter the regulation of this response. This hypothesis was derived in part from research on immunological responses to social threat in nonhuman animals. Healthy female participants were assigned to perform a speech and a math task in the presence or absence of an evaluative audience (SET or non-SET, respectively). As hypothesized, stimulated production of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) increased from baseline to poststressor in the SET condition, but was unchanged in the non-SET condition. Further, the increases in TNF-alpha production correlated with participants' cognitive appraisals of being evaluated. Additionally, the ability of glucocorticoids to shut down the inflammatory response was decreased in the SET condition. These findings underscore the importance of social evaluation as a threat capable of eliciting proinflammatory cytokine activity and altering its regulation.

Close relationships, inflammation, and health

Different aspects of personal relationships including social integration, social support, and social conflict have been related to inflammation. This article summarizes evidence linking the quality and quantity of relationships with gene expression, intracellular signaling mechanisms, and inflammatory biomarkers, and highlights the biological and psychological pathways through which close relationships impact inflammatory responses. Relationship conflict and lower social support can effectively modulate proinflammatory cytokine secretion both directly (via CNS/neural/endocrine/immune biobehavioral pathways), and indirectly, by promoting depression, emotional stress responses, and detrimental health behaviors. Accordingly, thorough assessments of health behaviors and attention to key methodological issues are necessary to identify the contributions of relationships to inflammation, and thus we highlight procedural issues to be considered in the design of studies. Despite some notable methodological challenges, the evidence suggests that learning more about how close relationships influence inflammation will provide important new insights into the ways that relationships impact health.

A critical review of human endotoxin administration as an experimental paradigm of depression

The syndrome called depression may represent the common final pathway at which different aetiopathogenic processes converge. One such aetiopathogenic process is innate immune system activation. Some depressed patients have increased levels of inflammatory cytokines and other immunologic abnormalities. It is not known whether immune system activation contributes to the pathogenesis of depressive symptoms. Supporting this possibility is the observation that in both rodents and humans, exogenous immune stimuli such as endotoxin can produce symptoms that resemble depression. A new approach to depression research would be to use immune stimuli to elicit depressive symptoms in humans. Here we review each of the symptoms elicited in humans by endotoxin administration, and compare this model to two other immune depression paradigms: interferon-alpha treatment and typhoid vaccine administration, to assess to what degree endotoxin administration represents a valid model of immune depression. We also review corresponding behavioral changes in rodents and the potential molecular pathways through which immune system activation produces each symptom.

Enhanced reactivity to pain in patients with rheumatoid arthritis

Introduction

Maladaptive physiological responses to stress appear to play a role in chronic inflammatory diseases such as rheumatoid arthritis (RA). However, relatively little stress research in RA patients has involved the study of pain, the most commonly reported and most impairing stressor in RA. In the present study, we compared psychophysical and physiological responses to standardized noxious stimulation in 19 RA patients and 21 healthy controls.

Methods

Participants underwent a single psychophysical testing session in which responses to a variety of painful stimuli were recorded, and blood samples were taken at multiple time points to evaluate the reactivity of cortisol, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) to the experience of acute pain.

Results

The findings suggest that RA patients display a fairly general hyperalgesia to mechanical and thermal stimuli across several body sites. In addition, while serum cortisol levels did not differ at baseline or following pain testing in patients relative to controls, the RA patients tended to show elevations in serum IL-6 and demonstrated enhanced pain-reactivity of serum levels of TNF-α compared with the healthy controls (P < 0.05).

Conclusions

These findings highlight the importance of pain as a stressor in RA patients and add to a small body of literature documenting amplified responses to pain in RA. Future studies of the pathophysiology of RA would benefit from the consideration of acute pain levels when comparing RA patients with other groups, and future trials of analgesic interventions in RA patients may benefit from evaluating the effects of such interventions on inflammatory activity.

[Psychoneuroimmunology: an update]

Psychoneuroimmunology (PNI) is closely associated with the bidirectional pathways between mind/brain and the immune system. PNI research represents a rapidly growing area within psychosomatic research. Recent studies in PNI are based mainly on the immunological concepts of Th1/Th2 dichotomy and inflammation. This review covers human PNI studies dealing with stress-associated changes in cytokine (Th1, Th2) levels in immune-related processes such as wound healing, atopic diseases as well as autoimmune and other inflammatory diseases. It is shown that PNI studies measuring immune activity near the site of the disease (e. g. woundhealing) and dealing with objective stressors show more consistent findings (stress-associated Th1/Th2 shift, stress-associated proinflammatory activation) than those dealing with chronic and complex diseases (e. g., autoimmune disease). This warrants the expansion of the methodological repertoire in future PNI research toward designs allowing for the investigation of complex psychosomatic phenomena.

Association between depression and coronary artery calcification in women with systemic lupus erythematosus

OBJECTIVES

To determine the associations between depression, cardiovascular risk factors and coronary artery calcification (CAC) in women with SLE and controls.

METHODS

CAC was measured using electron-beam CT (EBCT). Traditional, inflammatory and lupus-related risk factors as well as depressive symptoms (Center for Epidemiologic Studies Depression Scale-CES-D) were measured at a single study visit in 161 women with SLE and 161 age- and race frequency-matched female healthy controls.

RESULTS

Women with SLE reported more depressive symptoms than controls, with 27% of SLE and 15% of controls having CES-D scores suggestive of clinical depression. SLE women were more likely to have CAC, as well as more severe CAC compared with controls. Among the SLE women, depression was associated with greater than 2-fold odds of having any CAC [odds ratio (OR) 2.48; 95% CI 1.05, 5.87; P = 0.04], independent of traditional risk factors (age, hypertension and triglycerides) and inflammatory markers. However, when BMI was included among the covariates, the association between depression and CAC was attenuated, indicating the potential mediating role of BMI. Depression was not a risk factor for CAC in controls.

CONCLUSIONS

In women with SLE, depression was associated with CAC. This association was mediated by BMI. Depression and adiposity may add to the inflammatory burden of SLE, thus contributing to cardiovascular disease risk.

Associations of depression with C-reactive protein, IL-1, and IL-6: a meta-analysis

OBJECTIVE

To assess the magnitude and direction of associations of depression with C-reactive protein (CRP), interleukin (IL)-1, and IL-6 in community and clinical samples.

METHODS

Systematic review of articles published between January 1967 and January 2008 in the PubMed and PsycINFO electronic databases was performed. Effect sizes were calculated as stat d and meta-analyzed, using random-effects models.

RESULTS

Each inflammatory marker was positively associated with depression; CRP, d = 0.15 (95% CI = 0.10, 0.21), p < .001; IL-6, d = 0.25 (95% CI = 0.18, 0.31), p < .001; IL-1, d = 0.35 (95% CI = 0.03, 0.67), p = .03; IL-1ra, d = 0.25 (95% CI = 0.04, 0.46), p = .02. Associations were strongest in clinically depressed patient samples--but were also significant in community-based samples--and when clinical interviews were used. Studies adjusting for body mass index (BMI) had smaller associations, albeit significant. Relationships were inconsistent with respect to age, medication, and sex. Depression was related to CRP and IL-6 among patients with cardiac disease or cancer.

CONCLUSIONS

Depression and CRP, IL-1, and IL-6 are positively associated in clinical and community samples and BMI is implicated as a mediating/moderating factor. Continuity in clinic- and community-based samples suggests there is a dose-response relationship between depression and these inflammatory markers, lending strength to the contention that the cardiac (or cancer) risk conferred by depression is not exclusive to patient populations. Available evidence is consistent with three causal pathways: depression to inflammation, inflammation to depression, and bidirectional relationships.

The role of positive and negative interpersonal events on daily fatigue in women with fibromyalgia, rheumatoid arthritis, and osteoarthritis

OBJECTIVE

The current study tested whether daily interpersonal events predicted fatigue from one day to the next among female chronic pain patients.

DESIGN

Self-reported fatigue, daily events, pain, sleep quality, depressive symptoms, and functional health across 30 days were assessed in women with rheumatoid arthritis (RA: n = 89), Osteoarthritis (OA: n = 76), and Fibromyalgia syndrome (FM: n = 90).

MAIN OUTCOME MEASURES

Self-report fatigue measured on a 0 to 100 scale and fatigue affect from PANAS-X (Watson & Clark, 1994).

RESULTS

Multilevel analyses showed that both higher average levels of and daily increases in negative events predicted more fatigue, whereas daily increases in positive events predicted less fatigue. Across all pain conditions, increases in negative events continued to predict higher fatigue on the following day. Moreover, for participants with FM or RA, increases in positive events also predicted increased fatigue the following day. Daily increases in fatigue, in turn, predicted poorer functional health on both the same day and the next day.

CONCLUSION

These results indicate that both on average and on a daily basis, interpersonal events influence levels of fatigue beyond common physical and psychological correlates of chronic pain and highlight differences between chronic pain groups.

Low cortisol, high DHEA, and high levels of stimulated TNF-alpha, and IL-6 in women with PTSD

Posttraumatic stress disorder (PTSD) has been associated with hypothalamic-pituitary-adrenal (HPA) axis and immune function alterations; however, few studies have simultaneously investigated these systems in participants with PTSD. In this study, HPA axis and immune function in 26 women with PTSD with and without major depressive disorder was compared to 24 traumatized controls and to 21 nontraumatized controls. Posttraumatic stress disorder was associated with low cortisol and higher levels of DHEA and greater production of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) compared to traumatized and healthy controls. Women with PTSD and depression exhibited greater production of IL-6 and higher levels of dehydroepiandrosterone (DHEA) than those with PTSD, but without depression. These findings suggest dysregulated HPA axis and immune function in women with PTSD, and that comorbid depression may contribute to these abnormalities.