Evaluating individual biomarkers for predicting health risks in zoo-housed chimpanzees (Pan troglodytes) and bonobos (Pan paniscus)

Although biomarkers are often used for predicting morbidity and mortality in humans, similar data are lacking in our closest relatives. This study analyzed 16 biomarkers in zoo-housed chimpanzees and bonobos from serum samples collected during both routine and nonroutine veterinary immobilizations. Generalized linear and generalized linear mixed models were used to determine the efficacy of each biomarker to predict all-cause morbidity, defined as the presence of at least one chronic condition, or cardiac disease as a subset of all-cause morbidity. Cox proportional hazards models were used to examine associations between biomarkers and mortality risk from any cause. Analyses were conducted using two data sets for each species, one with all values retained (chimpanzees: n = 148; bonobos: n = 33) and the other from samples collected during routine immobilizations only (chimpanzees: n = 95; bonobos: n = 23). Consistent results across both data sets in chimpanzees included associations of higher cortisol with all-cause morbidity risk, lower creatinine with cardiac disease risk, and higher creatinine with mortality risk, and in bonobos were increased cardiac disease risk with higher cortisol and lower dehydroepiandrosterone-sulfate, fructosamine, and triglycerides. However, there were some inconsistencies between data sets, such as tumor necrosis factor-α predicting mortality risk positively in chimpanzees when all values were retained, but negatively for routine values only. Despite the close evolutionary relationships between chimpanzees and bonobos, the only result observed in both species was a negative association between albumin and mortality risk in the all values retained data sets. Thus, data suggest some biomarkers may be useful predictors of future health outcomes, although a better understanding of both individual and species variation in biomarkers and their contribution to health risks is needed.

Value Ranges and Clinical Comparisons of Serum DHEA-S, IL-6, and TNF-α in Western Lowland Gorillas

Simple Summary

Biomarkers are molecules found in the body that can indicate current physiological functioning and are frequently used to monitor health and diagnose disease. These biomarkers, such as hormones and immune markers, can provide valuable information on the health and welfare of animals. Knowledge on the normal levels of these biomarkers in various species is a crucial step for monitoring health and understanding disease. In this paper, we report assays and value ranges of biomarkers rarely measured in western lowland gorillas in human care. We also compare concentrations of each biomarker between clinical and non-clinical samples. The levels of the two immune biomarkers were higher in clinical samples, but the levels of the neuroendocrine biomarker were not significantly different between clinical and non-clinical samples. These data contribute toward eventually establishing reference ranges for these biomarkers and help improve our understanding of health and welfare in zoo-housed animals.

Abstract

Physiological data can provide valuable information about the health and welfare of animals. Unfortunately, few validated assays and a lack of information on species-typical levels of circulating biomarkers for wildlife make the measurement, interpretation, and practical application of such data difficult. We validated commercially available kits and calculated reference intervals (herein called “value ranges”) for dehydroepiandrosterone-sulfate (DHEA-S), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) in a sample of zoo-housed western lowland gorillas due to the roles these biomarkers play in stress and immune responses. For each biomarker, we present species-specific value ranges for a sample of gorillas in human care (n = 57). DHEA-S did not vary significantly by sex or age, while IL-6 was higher in males and older gorillas and TNF-α was higher in females but not associated with age. We also compared non-clinical with clinical samples (n = 21) to explore whether these biomarkers reflect changes in health status. There was no significant difference between clinical and non-clinical samples for DHEA-S, but both IL-6 and TNF-α were significantly higher in gorillas showing clinical symptoms or prior to death. Additional work is needed to improve our understanding of normal versus clinical variation in these biomarkers, and we encourage continued efforts to identify and validate additional biomarkers that can be used to inform assessments of health and welfare in wildlife.

Age, sex, and inflammatory markers predict chronic conditions, cardiac disease, and mortality among captive western lowland gorillas (Gorilla gorilla gorilla)

In humans, inflammatory markers predict health risks. As great apes experience many similar conditions, measuring inflammation may provide valuable health information. We examined four serum inflammatory markers in zoo-housed gorillas (n = 48): albumin, CRP, IL-6, and TNF-α. We first analyzed age- and sex-associated patterns, then used multimodel inference to evaluate models with age, sex, and inflammatory markers as predictors of all-cause morbidity, cardiac disease, and mortality. Older gorillas had lower albumin and higher IL-6, and males had higher albumin, lower CRP, and lower TNF-α. All-cause morbidity was best predicted by age, sex, and TNF-α, but the second model containing only age and sex was equivalent. Cardiac disease was best predicted by TNF-α alongside age and sex, with lower levels associated with increased risk. When outliers were removed, the model with TNF-α was second to the model containing only age and sex. Finally, mortality risk was best predicted by the model with only age and sex. Other models containing individual inflammatory markers were within top model sets for each health outcome. Our results indicate that age and sex are robust for predicting all-cause morbidity and mortality risk in gorillas; while models which include individual inflammatory markers also predict risk, they may not improve predictions over age and sex alone. However, given the prevalence of cardiac disease in great apes, these results suggest that TNF-α warrants further investigation. With their potential to provide valuable health information, data on inflammatory markers may contribute to the care and management of gorillas in human care.

COVID-19 threatens maternal mental health and infant development: possible paths from stress and isolation to adverse outcomes and a call for research and practice

The COVID-19 pandemic exposed mothers to stress and social isolation during the pre- and post-natal periods. The deleterious effects of stress on both pregnant women and their infants are well documented, with research suggesting that effects are exacerbated by reduced social support. In this brief report, we summarize evidence linking stress and social isolation to negative outcomes for mothers and infants and present a conceptual model featuring inflammation as a driving mechanism. There is strong evidence that the coronavirus pandemic will affect mothers and infants through immune pathways that, in previous research, have been shown to link stress and social isolation during the pre- and post-natal periods with deficits in maternal mental health and infant well-being and development across developmental stages. We close with recommendations for novel research, policy changes, and integrated clinical care that can address these biological threats to infants and mothers while leveraging the anti-inflammatory effects of social support.

The first multi-zoo application of an allostatic load index to western lowland gorillas (Gorilla gorilla gorilla)

Vertebrate stress responses are highly adaptive biological functions, maximizing survival probability in life-threatening situations. However, experiencing repeated and/or chronic stressors can generate physiological dysregulation and lead to disease. Because stress responses are multi-systemic and involve a wide range of physiological functions, identifying responses to stressors is best accomplished using integrated biomarker models. Allostatic load, defined as the physiological dysregulation that accumulates over the lifespan due to stressful experiences, is one such model. Allostatic load is measured using allostatic load indices, which are composites of biomarkers from multiple somatic systems. Previously, we reported the use of a 7-biomarker allostatic load index (albumin, CRH, cortisol, DHEA-S, glucose, IL-6, TNF-α) in western lowland gorillas housed at a single zoo. Herein, this index is expanded to examine allostatic load responses to lifetime stressors in gorillas from two additional zoos (n = 63) as well as two pooled samples. The index was created using quartile cut-points for each biomarker. Significant associations were observed between multiple predictor variables and allostatic load, including sex, age, number of stressful events (anesthetic events, zoo transfers, agonistic interactions with wounding, pregnancies), and rearing history (mother-reared, nursery-reared, wild-caught). Additionally, allostatic load was associated with indicators of morbidity (creatinine, cholesterol, triglycerides), age at death, and mortality risk. These results are consistent with those reported in human allostatic load research, suggesting allostatic load indices have potential as an investigative and clinical tool for gorillas and other great apes.

Direct and Indirect Pathways From Social Support to Health?

Objectives

We aimed to investigate potential direct and indirect pathways linking social support and health, while considering mental health and chronic inflammation as inter-related outcomes. The study also contributes to the literature through testing potential bidirectional relationships between social support, mental health, and chronic inflammation.

Methods

This study uses Structural Equation Modeling and two waves of the National Social Life, Health, and Aging Project (NSHAP), including 1,124 community-living older adults aged 57–85 years at Wave 1 (2005).

Results

Analyses show that social support influenced mental health indirectly through better self-esteem. Moreover, social support was associated with lower levels of chronic inflammation but chronic inflammation did not influence social support.

Discussion

The growing number of older adults with an aging population urgently calls for a greater understanding of factors influencing their physical and mental health. The results of this study demonstrate the importance of social support in older adults’ health, while specifically focusing on understudied indirect pathways from social support to health.

Coping and quality of life in Turkish women living with ovarian cancer

BACKGROUND

This study investigated the utilization of both problem and emotion focused coping strategies and their association with aspects of quality of life among Turkish women with ovarian cancer undergoing chemotherapy.

MATERIALS AND METHODS

The convenience sample consisted of 228 patients in all disease stages. The data were collected using the brief COPE, QOL-Cancer patient tool, sociodemographic sheet, and medical variables were gathered from patients' medical charts.

RESULTS

Findings reveal that quality of life is moderately high for this group of cancer patients, despite some specific negative facets of the illness and treatment experience. Acceptance, emotional support and religion were the most frequently used problem-focused coping strategies and self-distraction, venting and behavioral disengagement were the most frequently used emotion-focused coping strategies reported by patients. Overall quality of life and, particularly, psychological and spiritual well- being scores of younger patients were lower. Patients reported using significantly more problem-focused coping than emotion-focused coping, and more problem-focused and less emotion-focused coping predicted greater quality of life. Problem-focused coping was related to patients' physical and spiritual well-being and emotion- focused coping was related inversely with psychological and social well-being.

CONCLUSIONS

Coping strategies are influential in patient quality of life and their psychosocial adaptation to ovarian cancer. Psycho-oncology support programs are needed to help patients to frequent use of problem-focused coping and reduce emotion- focused coping strategies to improve overall quality of life.

Source-specific social support and circulating inflammatory markers among white-collar employees

BACKGROUND

Despite known beneficial effects of social support on cardiovascular health, the pathway through which sources of support (supervisor, coworkers, family/friends) influence inflammatory markers is not completely understood.

PURPOSE

We investigated the independent and moderating associations between social support and inflammatory markers.

METHODS

A total of 137 male white-collar employees underwent a blood draw for measurement of high-sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), monocyte and leukocyte counts, and completed a questionnaire on social support.

RESULTS

Multivariable linear regression analyses controlling for covariates revealed that supervisor support was inversely associated with IL-6 (β = -0.24, p < 0.01) while coworker support was marginally associated with TNF-α (β = -0.16, p < 0.10). Support from family/friends was not associated with inflammatory markers.

CONCLUSION

Social support from the immediate supervisor may be a potential mechanism through which social support exerts beneficial effects on inflammatory markers in working men.

Social support as a predictor exhaled nitric oxide in healthy individuals across time

Psychosocial factors such as social support and depression have long been associated with health outcomes. Elevated depressive symptoms are usually associated with worse health outcomes, whereas social support has been related to improvements in health. Nitric oxide levels are an important marker of both cardiovascular health and immune function. Research suggests that exhaled nitric oxide is affected by stress, negative affect, and depression; however, the effect of social support has not been previously explored. Thus, we sought to examine the association of social support, negative affect, and depression with exhaled nitric oxide in a group of 35 healthy individuals (10 males and 25 females) with a mean age of 20.5years across five weekly assessments. Results showed that changes in social support within individuals were positively associated with levels of exhaled nitric oxide independent of other psychosocial factors. Further exploration of the health implications of this positive relationship between airway nitric oxide and social support is necessary.

Social support modulates splenocyte glucocorticoid sensitivity in piglets exposed to social deprivation stress

There is growing evidence that positive social interactions can attenuate the effects of stressful life experiences. However, little is known about the benefits of social partners on stress responses in farm animals. Therefore, in this study we examined the effects of social support on the endocrine and immune stress responses to a single 4h social deprivation in domestic piglets at 7, 21 or 35days of age. The piglets were socially deprived of their mother and littermates. They were left alone (DA) or in the presence of a familiar (DF) or unfamiliar (DU) age-matched piglet. Non-socially deprived piglets served as a control. DA piglets displayed elevated plasma cortisol levels, higher lipopolysaccharide (LPS)-stimulated proliferation of splenocytes and increased TNF-α and IL-6 production in splenocyte cultures than the control piglets. There were no significant buffering effects of social partners on stress-induced plasma cortisol levels and splenocyte proliferation in response to LPS. However, the presence of an age-matched conspecific diminished the IL-6 production by splenocytes in younger, socially deprived piglets, and it reduced the TNF-α release in the older piglets. Compared to the controls, LPS-stimulated splenocytes from DA piglets were more resistant to the inhibitory effects of cortisol, which was demonstrated by a higher proliferative response and increased production of pro-inflammatory cytokines. The dose-dependent cortisol resistance was attenuated by the presence of a familiar or an unfamiliar conspecific at each of the three age categories. Indeed, in the present study, the familiarity level of the social partners did not seem to play a role in the alleviation of social stress-induced inflammatory activity and splenocyte cortisol resistance. In addition, the buffering effect of social support provided by an age-matched conspecific was more pronounced in older piglets. Conclusively, these findings suggest that social support is an important factor for enhancing piglets' abilities to cope with stressful challenges, and it may be a key approach needed to improve the health and welfare of farm animals.

Social support predicts inflammation, pain, and depressive symptoms: longitudinal relationships among breast cancer survivors

OBJECTIVE

Pain and depressive symptoms are commonly experienced by cancer survivors. Lower social support is linked to a variety of negative mental and physical health outcomes among survivors. Immune dysregulation may be one mechanism linking low social support to the development of pain and depressive symptoms over time. Accordingly, the goal of the present study was to examine the relationships among survivors' social support, pain, depressive symptoms, and inflammation.

METHODS

Breast cancer survivors (N=164, stages 0-IIIA) completed two study visits, one before any cancer treatment and the other 6 months after the completion of surgery, radiation, or chemotherapy, whichever came last. Women completed self-report questionnaires assessing social support, pain, and depressive symptoms, and provided a blood sample at both visits.

RESULTS

Survivors with lower social support prior to treatment experienced higher levels of pain and depressive symptoms over time than their more socially supported counterparts. Furthermore, women with lower pretreatment social support had higher levels of IL-6 over time, and these elevations in IL-6 predicted marginally larger increases in depressive symptoms.

CONCLUSIONS

The results of this study suggest that social support at the time of diagnosis predicts the post-treatment development of pain, depressive symptoms, and inflammation. Consequently, early interventions targeting survivors' social networks could improve quality of life during survivorship.

Depression and family interaction among low-income, predominantly hispanic cancer patients: a longitudinal analysis

PURPOSE

Among cancer patients, family interaction has been associated with depression. According to the stress generation theory, depression among cancer patients triggers stressful interpersonal events that contribute to poor family interactions and additional depression. This conflict may occur with a spouse/partner or other family member, including extended family. This study evaluated the longitudinal association between depression and marital and family conflict among low-income, predominantly Hispanic cancer patients.

METHODS

Data were collected during a randomized controlled clinical trial of depression treatment among 472 low-income cancer patients with baseline depression scores of 10 or more on the Patient Health Questionnaire-9 and whose depression symptoms and negative family interactions were assessed at baseline and at 6, 12, 18, and 24 months. Considering that not all participants were in an intimate relationship, only 237 participants were included in the analysis of marital conflict. Mixed linear modeling with and without decomposition of between- and within-person variability was conducted to examine the longitudinal association between family interaction and depression.

RESULTS

Overall, family conflict was significantly associated with changes in depression over time, and marital conflict was significantly associated with mean depression levels over 2 years. In addition, within-subject change in both marital and family conflict was significantly associated with within-patient deviation from average depression levels.

CONCLUSIONS

Findings provide evidence of an association between depression and negative family interaction among depressed cancer patients. Cancer patients with clinically significant depressive symptoms may benefit from clinical assessment and psychotherapy relevant to family interaction.

Autonomy, positive relationships, and IL-6: evidence for gender-specific effects

OBJECTIVES

A body of evidence indicates that women value relationship-centred aspects of well-being more than men do, while men value autonomy-centred aspects of well-being more than women do. The current study examined whether gender moderates relations between autonomy and positive relationships and interleukin-6 (IL-6), a cytokine associated with inflammatory processes. Aspects of well-being consistent with gender-linked values were expected to be most health protective such that positive relationships would predict lower IL-6 only or more strongly in women, and autonomy would predict lower IL-6 only or more strongly in men.

METHODS

In the first study, a sample of 119 older adults (55% female) living in Kentucky were visited in their homes for interviews and blood draws. In the second study, a sample of 1,028 adults (45% female) living across the United States underwent a telephone interview followed by a visit to a research centre for blood draws.

RESULTS

In the Kentucky sample, autonomy was quadratically related to IL-6 such that moderate autonomy predicted higher IL-6; this effect was stronger in men. In the US national sample, more positive relationships were associated with lower IL-6 in women only. When the national sample was restricted to match the Kentucky sample, moderate autonomy was again associated with higher IL-6 in men only.

CONCLUSIONS

Results provide preliminary evidence for gender-specific effects of positive relationships and autonomy on IL-6. Further work is needed to establish the generalizability of these effects to different ages, cultures, and health statuses.

STATEMENT OF CONTRIBUTION

What is already known on this subject? A host of previous work indicates that women value relationship-centred aspects of well-being more than men, while men value autonomy-centred aspects of well-being more than women. Further, there is some evidence suggesting that well-being consistent with gender-linked values is more health protective, such that relationships are more protective for women than for men, while autonomy is more protective for men than for women. What does this study add We provide preliminary support for the hypothesis that gender moderates the associations of autonomy and positive relationships with IL-6. Specifically, higher levels of positive relationships may be associated with lower IL-6 in women only, whereas moderate levels of autonomy may be associated with higher IL-6 in males only, particularly among older adults.

Psychological pathways linking social support to health outcomes: a visit with the "ghosts" of research past, present, and future

Contemporary models postulate the importance of psychological mechanisms linking perceived and received social support to physical health outcomes. In this review, we examine studies that directly tested the potential psychological mechanisms responsible for links between social support and health-relevant physiological processes (1980s-2010). Inconsistent with existing theoretical models, no evidence was found that psychological mechanisms such as depression, perceived stress, and other affective processes are directly responsible for links between support and health. We discuss the importance of considering statistical/design issues, emerging conceptual perspectives, and limitations of our existing models for future research aimed at elucidating the psychological mechanisms responsible for links between social support and physical health outcomes.

Relationships and Inflammation across the Lifespan: Social Developmental Pathways to Disease

There are well documented links between close relationships and physical health, such that those who have supportive close relationships have lower rates of morbidity and mortality compared to those who do not. Inflammation is one mechanism that may help to explain this link. Chronically high levels of inflammation predict disease. Across the lifespan, people who have supportive close relationships have lower levels of systemic inflammation compared to people who have cold, unsupportive, conflict-ridden relationships. Not only are current relationships associated with inflammation, but past relationships are as well. In this article, we will first review the literature linking current close relationships across the lifespan to inflammation. We will then explore recent work showing troubled past relationships also have lasting consequence on people's inflammatory levels. Finally, we will explore developmental pathways that may explain these findings.

Relationship between loneliness and proangiogenic cytokines in newly diagnosed tumors of colon and rectum

OBJECTIVE

To investigate the association of serum levels of proangiogenic cytokines with different indices of social support and loneliness by measuring the levels of expression of two important proangiogenic cytokines, vascular endothelial growth factor (VEGF), and interleukin-6 in tumors of colon and rectum. Lack of social support has been prospectively associated with cancer progression.

METHODS

Fifty-one newly diagnosed patients with colorectal tumors (mean age, 68.3 years) completed two measures of loneliness 1 to 2 days before their surgical treatment. The first was an explicit self-report questionnaire, which tapped into negative feelings as a result of low social support. The second was a standardized computer-based task, which measured loneliness implicitly. Immunohistochemical analyses were performed on tumor tissues post surgery to determine the expression of cytokines.

RESULTS

Logistic regression showed that higher levels of implicit loneliness independently predicted stronger expression of VEGF, controlling for Dukes stage and explicit loneliness, both of which were nonsignificant predictors. No significant relationships were found between the loneliness measures and interleukin-6.

CONCLUSIONS

The results of this study suggest VEGF to be an angiogenic mechanism through which loneliness may lead to worse cancer-related outcomes. Implications are discussed in terms of devising targeted psychosocial and immunotherapeutic interventions for cancer patients with low social support.

Direct and buffering effects of social support among gynecologic cancer survivors

BACKGROUND

There are few studies of QoL among long-term gynecologic cancer survivors; available data suggest significant sequelae of disease and treatment. Research clarifying circumstances that improve difficult survivorship trajectories is lacking.

PURPOSE

The present study examines whether social support moderates the relationship between physical functioning and psychological outcomes by testing the stress-buffering hypothesis.

METHODS

Participants (N = 260) were gynecologic cancer survivors (cervical, n = 47; endometrial, n = 133; ovarian, n = 69; vulvar, n = 11). Compromised physical health was conceptualized as multidimensional. Social support (SNI, PSS-Fa, PSS-Fr, ISEL) was tested as a buffer of adverse psychological outcomes (IES-R, CES-D).

RESULTS

Results for traumatic stress provided evidence for buffering; whereas social support was of general benefit for depressive symptoms. Effects varied by source and type of support.

CONCLUSIONS

These results suggest that circumstances for gynecologic cancer survivors burdened with physical symptoms may be worse for those with fewer support resources, providing needed insight into a common target of psychosocial interventions for cancer survivors.

Psychological factors in immunomodulation induced by cancer surgery: a review

The immune system's efficacy in detecting and destroying cancer cells varies considerably throughout the stages of cancer development and its role may be critical particularly during the surgical period. Although surgery causes tumor cells to shed into the blood, immune cells have the capacity to destroy these tumor cells. However, surgery also suppresses cytotoxic capacity. It is particularly during this surgical period that psychological factors can have a significant dampening or strengthening impact on surgery-related immunomodulation response, thus exerting an effect on survival. This review describes the immune changes during the peri-surgical period and the influences psychological factors have on immune function, including the immune effects caused by psychological interventions in cancer patients. We recommend that future studies exploring the role of psychological factors on immune function and survival focus more on their influence during the peri-surgical period.

The inextricable nature of mental and physical health: implications for integrative care

There is growing evidence that physical health problems are caused and exacerbated by psychological factors. Research indicates that psychological distress leads to physical disease through impairment of the neuroendocrine system and its interface with the body's immune response. However, the current health care delivery system splinters care into "psychiatric" and "physical" health silos. New approaches are needed to assure adequate professional knowledge of behavioral health at basic licensure, to increase the use of advanced practice psychiatric-mental health nurses in primary care settings, to identify and teach behavioral competencies for primary care providers, and to fund the design and evaluation of integrative models of care.

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.

Coping and quality of life among women extensively treated for gynecologic cancer

The current study examined the use of engagement and avoidant coping strategies among advanced-stage gynecologic cancer patients who were facing the long-term stressors of extensive chemotherapy and advanced disease. Patients were compared to a reference group of early-stage patients who had received more limited treatment. Compared to the reference group, extensively-treated women more frequently utilized both engagement and avoidant strategies including active coping, seeking social support, and mental disengagement. Use of engagement coping strategies such as active coping and seeking social support were not significantly related to quality of life or mood. However, avoidant coping strategies, including disengagement and cognitive avoidance, were strongly associated with poorer well-being and more distressed mood. Moreover, relationships between coping and quality of life differed between the extensively-treated patients and patients in the limited treatment reference group. The use of avoidance and seeking instrumental support were associated with poorer outcomes among extensively-treated patients but not among the limited treatment group. Results of the current study suggest that coping patterns and outcomes may be more pronounced among cancer patients contending with severe disease and extensive treatment and that avoidant coping strategies may be particularly detrimental with respect to these patients' mood and quality of life.

Social Support and Health: A Review of Physiological Processes Potentially Underlying Links to Disease Outcomes

Social support has been reliably related to lower rates of morbidity and mortality. An important issue concerns the physiological mechanisms by which support influences such health endpoints. In this review, I examine evidence linking social support to changes in cardiovascular, neuroendocrine, and immune function. Consistent with epidemiological evidence, social support appears to be related to more positive "biological profiles" across these disease-relevant systems. Recent research on immune-mediated inflammatory processes is also starting to provide data on more integrative physiological mechanisms potentially linking social support to health. The implications of these links, along with future research directions are discussed.

Emotional style, nasal cytokines, and illness expression after experimental rhinovirus exposure

Psychosocial factors moderate the expression of illness during upper respiratory virus infections but past attempts to define mediational pathways were not successful. Here, we used a model of experimental rhinovirus infection in humans to evaluate three proinflammatory cytokines for their potential role in mediating the previously documented association between positive emotional style and illness. After assessing emotional style in 327 healthy adults, each was exposed to one of two strains of rhinovirus and followed for 5 days in quarantine. Symptoms/signs, nasal lavage IL-1beta, IL-6, and IL-8 protein, and viral shedding were assessed at baseline and on each of the 5 days after exposure. Virus-specific antibody was assessed at baseline and 28 days after challenge. An analysis of the data for 234 subjects with documented infection showed that nasal IL-1beta, IL-6, and IL-8 protein levels were all associated with greater illness expression but IL-6 was by far the best predictor of nasal signs and symptoms. Lower positive emotional style was associated with greater objective and subjective markers of illness and these associations were decreased substantially by controlling for IL-6 but not for IL-1beta or IL-8. These results are consistent with the hypothesis that IL-6 acts as a biological mediator in linking positive emotional style to illness expression during rhinovirus infection.

Psychosocial factors and interleukin-6 among women with advanced ovarian cancer

BACKGROUND

Relations among psychological stress, depression, social support, and interleukin-6 (IL-6, a proinflammatory cytokine) have been documented in humans and animals. Because elevated IL-6 is associated with a poorer prognosis among ovarian cancer patients and has been implicated in the metastasis of ovarian cancer, the current study examined relations between psychosocial factors and IL-6 among women with advanced-stage ovarian cancer.

METHODS

Sixty-one ovarian cancer patients completed assessments of social support, distressed mood, and quality of life before surgery. Peripheral blood was drawn preoperatively, and the plasma was assayed for IL-6. Ascites samples were also assayed for IL-6 for a subset of patients.

RESULTS

Both IL-6 levels and distressed mood were elevated among patients. After statistically adjusting effects of age and disease stage, social attachment was associated with lower levels of IL-6 in peripheral blood (P = 0.03), whereas poorer health-related quality of life was associated with higher IL-6 (P values ranged from 0.01 to 0.03 on different measures). This pattern of relations was also found in the ascites. Moreover, IL-6 levels in peripheral blood plasma correlated significantly with IL-6 in the ascites (P < 0.001), suggesting that peripheral IL-6 reflects IL-6 levels at the site of the tumor.

CONCLUSIONS

Results suggest that social support may play a protective role with respect to IL-6 elevations, and IL-6 may be an independent marker of health-related quality of life among ovarian cancer patients. Processes involving IL-6 represent possible pathways by which behavioral factors may contribute to disease outcomes among women with ovarian cancer.

Vascular endothelial growth factor and social support in patients with ovarian carcinoma

BACKGROUND

The modulation of immunologic activities relevant to cancer by behavioral factors, such as stress, depression, and social support, is well documented. However, associations of behavioral factors with cytokines involved in tumor angiogenesis have not been studied. Vascular endothelial growth factor (VEGF) is a key cytokine that is capable of stimulating tumor angiogenesis, and it has been associated with poorer survival in patients with ovarian carcinoma. VEGF is modulated by a variety of behaviorally sensitive factors, including sympathetic activation. This study examined relationships of social support and depressive symptoms with VEGF levels in preoperative patients with ovarian carcinoma.

METHODS

Twenty-four women with ovarian carcinoma and 5 women with benign pelvic masses were recruited at the presurgical clinic visit, received psychosocial surveys, including the Functional Assessment of Cancer Therapy (Quality of Life) survey and the Profile of Mood States, and a blood draw. Serum VEGF levels were assessed by enzyme-linked immunosorbent assay. Analyses controlled for disease stage.

RESULTS

Women with ovarian carcinoma who reported higher levels of social well being had lower levels of VEGF (P = 0.005). Greater support from friends and neighbors (P = 0.005) and less distance from friends (P = 0.04) were facets of social well being that were associated with lower VEGF levels. Individuals who reported greater helplessness (P = 0.03) or worthlessness (P = 0.08) had higher VEGF levels, but depression as a whole (P > 0.50) was not related to VEGF levels.

CONCLUSIONS

Higher levels of social well being were correlated with lower VEGF levels in presurgical patients with ovarian carcinoma. These findings suggest a possible mechanism by which poor social support may be associated with disease progression. Further study of these relations may demonstrate novel pathways relating biobehavioral factors to tumor growth and disease progression.