Stress, depression, the immune system, and cancer
TL;DR: The evidence that various cellular and molecular immunological factors are compromised in chronic stress and depression is overviewed and the clinical implications of these factors in the initiation and progression of cancer are discussed.
Abstract: The links between the psychological and physiological features of cancer risk and progression have been studied through psychoneuroimmunology. The persistent activation of the hypothalamic-pituitary-adrenal (HPA) axis in the chronic stress response and in depression probably impairs the immune response and contributes to the development and progression of some types of cancer. Here, we overview the evidence that various cellular and molecular immunological factors are compromised in chronic stress and depression and discuss the clinical implications of these factors in the initiation and progression of cancer. The consecutive stages of the multistep immune reactions are either inhibited or enhanced as a result of previous or parallel stress experiences, depending on the type and intensity of the stressor and on the animal species, strain, sex, or age. In general, both stressors and depression are associated with the decreased cytotoxic T-cell and natural-killer-cell activities that affect processes such as immune surveillance of tumours, and with the events that modulate development and accumulation of somatic mutations and genomic instability. A better understanding of the bidirectional communication between the neuroendocrine and immune systems could contribute to new clinical and treatment strategies.
Citations
More filters
TL;DR: PNI researchers have used animal and human models to learn how the immune system communicates bidirectionally with the central nervous and endocrine systems and how these interactions impact on health.
Abstract: Folk wisdom has long suggested that stressful events take a toll on health. The field of psychoneuroimmunology (PNI) is now providing key mechanistic evidence about the ways in which stressors--and the negative emotions that they generate--can be translated into physiological changes. PNI researchers have used animal and human models to learn how the immune system communicates bidirectionally with the central nervous and endocrine systems and how these interactions impact on health.
1,845 citations
TL;DR: A biologically plausible, multilevel theory is proposed that describes neural, physiologic, molecular, and genomic mechanisms that link experiences of social-environmental stress with internal biological processes that drive depression pathogenesis and may shed light on several important questions including how depression develops, why it frequently recurs, and why it is strongly predicted by early life stress.
Abstract: Major life stressors, especially those involving interpersonal stress and social rejection, are among the strongest proximal risk factors for depression. In this review, we propose a biologically plausible, multilevel theory that describes neural, physiologic, molecular, and genomic mechanisms that link experiences of social-environmental stress with internal biological processes that drive depression pathogenesis. Central to this social signal transduction theory of depression is the hypothesis that experiences of social threat and adversity up-regulate components of the immune system involved in inflammation. The key mediators of this response, called proinflammatory cytokines, can in turn elicit profound changes in behavior, which include the initiation of depressive symptoms such as sad mood, anhedonia, fatigue, psychomotor retardation, and social-behavioral withdrawal. This highly conserved biological response to adversity is critical for survival during times of actual physical threat or injury. However, this response can also be activated by modern-day social, symbolic, or imagined threats, leading to an increasingly proinflammatory phenotype that may be a key phenomenon driving depression pathogenesis and recurrence, as well as the overlap of depression with several somatic conditions including asthma, rheumatoid arthritis, chronic pain, metabolic syndrome, cardiovascular disease, obesity, and neurodegeneration. Insights from this theory may thus shed light on several important questions including how depression develops, why it frequently recurs, why it is strongly predicted by early life stress, and why it often co-occurs with symptoms of anxiety and with certain physical disease conditions. This work may also suggest new opportunities for preventing and treating depression by targeting inflammation.
1,361 citations
TL;DR: Play, affiliative behaviors and some vocalizations appear to be the most promising convenient indicators for assessing positive experiences in laboratory and farm animals under commercial conditions.
1,086 citations
TL;DR: Chronic behavioral stress results in higher levels of tissue catecholamines, greater tumor burden and more invasive growth of ovarian carcinoma cells in an orthotopic mouse model, and β-adrenergic activation of the cAMP–PKA signaling pathway is identified as a major mechanism by which behavioral stress can enhance tumor angiogenesis in vivo and thereby promote malignant cell growth.
Abstract: Chronic stress promotes tumor growth and angiogenesis in a mouse model of ovarian carcinoma
1,046 citations
TL;DR: This review integrates clinical, cellular and molecular studies to provide a mechanistic understanding of the interface between biological and behavioural influences in cancer, and identifies novel behavioural or pharmacological interventions that might help improve cancer outcomes.
Abstract: Stress does not cause cancer per se, but depression and a lack of social support might influence cancer progression and clinical outcome. Can identification of the molecular and biological mechanisms involved be used to improve patient treatment? Epidemiological studies indicate that stress, chronic depression and lack of social support might serve as risk factors for cancer development and progression. Recent cellular and molecular studies have identified biological processes that could potentially mediate such effects. This review integrates clinical, cellular and molecular studies to provide a mechanistic understanding of the interface between biological and behavioural influences in cancer, and identifies novel behavioural or pharmacological interventions that might help improve cancer outcomes.
841 citations
References
More filters
TL;DR: The long-term effect of the physiologic response to stress is reviewed, which I refer to as allostatic load, which is the ability to achieve stability through change.
Abstract: Over 60 years ago, Selye1 recognized the paradox that the physiologic systems activated by stress can not only protect and restore but also damage the body. What links these seemingly contradictory roles? How does stress influence the pathogenesis of disease, and what accounts for the variation in vulnerability to stress-related diseases among people with similar life experiences? How can stress-induced damage be quantified? These and many other questions still challenge investigators. This article reviews the long-term effect of the physiologic response to stress, which I refer to as allostatic load.2 Allostasis — the ability to achieve stability through change3 — . . .
5,932 citations
TL;DR: Celsus described four of the five cardinal signs of inflammation 2000 years ago, and Eustachio discovered the adrenal glands almost 500 years ago; but not until 1936 did Selye note that in rats exposed to stressors, the adrenAL glands were enlarged, and the thymus and lymph nodes shrunken.
Abstract: Celsus described four of the five cardinal signs of inflammation 2000 years ago, and Eustachio discovered the adrenal glands almost 500 years ago, but not until 1936 did Selye note that in rats exposed to stressors, the adrenal glands were enlarged, and the thymus and lymph nodes shrunken.1–3 Cortisone, the active principle of the adrenal glands, was isolated by Kendall and Reichstein in the late 1940s and shown to suppress immune organs. These scientists, along with Hench, received the Nobel Prize in Physiology and Medicine, after Hench and colleagues showed that cortisone could ameliorate rheumatoid arthritis.4,5 In recent . . .
2,432 citations
TL;DR: The effect of psychosocial intervention on time of survival of 86 patients with metastatic breast cancer was studied prospectively and survival plots indicated that divergence in survival began at 20 months after entry, or 8 months after intervention ended.
2,248 citations
TL;DR: Psychiatric interventions that enhance effective coping and reduce affective distress appear to have beneficial effects on survival but are not proposed as an alternative or independent treatment for cancer or any other illness or disease.
Abstract: Objectives: We evaluated recurrence and survival for 68 patients with malignant melanoma who participated in a 6-week structured psychiatric group intervention 5 to 6 years earlier, shortly after their diagnosis and initial surgical treatment. We also explored the role of several factors as possible predictors of outcome. Design: This was a randomized controlled experimental study. The Cox proportion hazards regression model was used to quantify the relationship between treatment and the outcomes adjusted by the covariates (age, sex, Breslow depth, tumor site, baseline Profile of Mood States Total Mood Disturbance, baseline active-behavioral coping, baseline natural killer cell activity, and treatment [ie, group intervention]). The stepwise procedure was used for covariate selection. Results: For control patients, there was a trend for recurrence (13/34) and a statistically significant greater rate of death (10/34) than for experimental patients (7/34 and 3/34, respectively). We found that being male and having a greater Breslow depth predicted greater recurrence and poorer survival. Analysis of multiple covariates found that only Breslow depth and treatment (ie, group intervention) were significant. Adjusting for Breslow depth, treatment effect remained significant. Finally, baseline affective distress and baseline coping were significant psychobehavioral predictors for recurrence and survival. Surprisingly, higher levels of baseline distress as well as baseline coping and enhancement of active-behavioral coping over time were predictive of lower rates of recurrence and death. Conclusion: Psychiatric interventions that enhance effective coping and reduce affective distress appear to have beneficial effects on survival but are not proposed as an alternative or independent treatment for cancer or any other illness or disease. However, the exact nature of this relationship warrants further investigation.
1,026 citations
TL;DR: A broad meta-analysis of the relations of both depression and stressors to immunological assays revealed that for both major depression and naturally occurring stressors the following effects are shared: leukocytosis, increased CD4/CD8 ratios, reduced proliferative response to mitogen, and reduced NK cell cytotoxicity.
Abstract: This is a broad meta-analysis of the relations of both depression and stressors to immunological assays. The number of study samples (greater than 180) and measures (greater than 40) is much more extensive than any so far. Analyses are done by both fixed and random effects. By a fixed-effects analysis, both major depression and naturally occurring acute stressors are associated with (1) an overall leukocytosis, (2) mild reductions in absolute NK-cell counts and relative T-cell proportions, (3) marginal increases in CD4/CD8 ratios, and (4) moderate decreases in T- and NK-cell function. However, the degree of heterogeneity of the studies' results raises questions about their robustness. Therefore, we also did the first random effects analysis to estimate what is likely to appear in future studies. For depression, the analysis showed the immunological correlates included (1) an overall leukocytosis, manifesting as a relative neutrophilia and lymphoenia; (2) increased CD4/CD8 ratios; (3) increased circulating haptoglobin, PGE(2), and IL-6 levels; (4) reduced NK-cell cytotoxicity; and (5) reduced lymphocyte proliferative response to mitogen. For stressors, the random effects analysis showed that future studies are likely to find the following effects: (1) an overall leukocytosis, manifesting as an absolute lymphocytosis; (2) alterations in cytotoxic lymphocyte levels, CD4/CD8 ratios, and natural killer cell cytotoxicity with the direction of change depending on the chronicity of the stressor; (3) a relative reduction of T-cell levels; (3) increased EBV antibody titers; (4) reduced lymphocyte proliferative response and proportion of IL-2r bearing cells following mitogenic stimulation; and (5) increased leukocyte adhesiveness. The random-effects analysis revealed that for both major depression and naturally occurring stressors the following effects are shared: leukocytosis, increased CD4/CD8 ratios, reduced proliferative response to mitogen, and reduced NK cell cytotoxicity. The implications for these findings for disease susceptibility and the pathophysiology of these conditions is discussed.
923 citations