Psychosocial influences on immunity, including effects on immune maturation and senescence

An individual-based model to explore the impact of psychological stress on immune infiltration into tumour spheroids

In recentin vitroexperiments on co-culture between breast tumour spheroids and activated immune cells, it was observed that the introduction of the stress hormone cortisol resulted in a decreased immune cell infiltration into the spheroids. Moreover, the presence of cortisol deregulated the normal levels of the pro- and anti-inflammatory cytokines IFN-γand IL-10. We present an individual-based model to explore the interaction dynamics between tumour and immune cells under psychological stress conditions. With our model, we explore the processes underlying the emergence of different levels of immune infiltration, with particular focus on the biological mechanisms regulated by IFN-γand IL-10. The set-up of numerical simulations is defined to mimic the scenarios considered in the experimental study. Similarly to the experimental quantitative analysis, we compute a score that quantifies the level of immune cell infiltration into the tumour. The results of numerical simulations indicate that the motility of immune cells, their capability to infiltrate through tumour cells, their growth rate and the interplay between these cell parameters can affect the level of immune cell infiltration in different ways. Ultimately, numerical simulations of this model support a deeper understanding of the impact of biological stress-induced mechanisms on immune infiltration.

An integrated framework for quantifying immune-tumour interactions in a 3D co-culture model

Investigational in vitro models that reflect the complexity of the interaction between the immune system and tumours are limited and difficult to establish. Herein, we present a platform to study the tumour-immune interaction using a co-culture between cancer spheroids and activated immune cells. An algorithm was developed for analysis of confocal images of the co-culture to evaluate the following quantitatively; immune cell infiltration, spheroid roundness and spheroid growth. As a proof of concept, the effect of the glucocorticoid stress hormone, cortisol was tested on 66CL4 co-culture model. Results were comparable to 66CL4 syngeneic in vivo mouse model undergoing psychological stress. Furthermore, administration of glucocorticoid receptor antagonists demonstrated the use of this model to determine the effect of treatments on the immune-tumour interplay. In conclusion, we provide a method of quantifying the interaction between the immune system and cancer, which can become a screening tool in immunotherapy design.

Early maternal and paternal caregiving moderates the links between preschoolers' reactivity and regulation and maturation of the HPA-immune axis

While early caregiving and child's temperamental dispositions work in concert to shape social-emotional outcomes, their unique and joint contribution to the maturation of the child's stress and immune systems remain unclear. We followed children longitudinally from infancy to preschool to address the buffering effect of early parenting on the link between temperamental dysregulation and hypothalamic-pituitary-adrenal (HPA)-immune axis in preschool-aged children. Participants included 47 typically developing children and their 94 parents in both mother-father and two-father families followed across the first 4-years of family formation. In infancy, we observed parent-infant synchrony and measured parental oxytocin; in preschool, we observed temperamental reactivity and self-regulation and assessed children's cortisol and secretory Immunoglobulin A (s-IgA), biomarkers of the stress and immune systems. Greater self-regulation and lower negative emotionality were associated with lower baseline s-IgA and cortisol, respectively. However, these links were defined by interactive effects so that preschoolers with low self-regulation displayed higher s-IgA levels only in cases of low parent-infant synchrony and negative emotionality linked with greater baseline cortisol levels only when parental oxytocin levels were low. Results emphasize the long-term stress-buffering role of the neurobiology of parental care, demonstrate comparable developmental paths for mothers and fathers, and delineate the complex developmental cascades to the maturation of children's stress-management systems.

Social and population health science approaches to understand the human microbiome

The microbiome is now considered our 'second genome' with potentially comparable importance to the genome in determining human health. There is, however, a relatively limited understanding of the broader environmental factors, particularly social conditions, that shape variation in human microbial communities. Fulfilling the promise of microbiome research - particularly the microbiome's potential for modification - will require collaboration between biologists and social and population scientists. For life scientists, the plasticity and adaptiveness of the microbiome calls for an agenda to understand the sensitivity of the microbiome to broader social environments already known to be powerful predictors of morbidity and mortality. For social and population scientists, attention to the microbiome may help answer nagging questions about the underlying biological mechanisms that link social conditions to health. We outline key substantive and methodological advances that can be made if collaborations between social and population health scientists and life scientists are strategically pursued.

From wholes to fragments to wholes-what gets lost in translation?

The highly demanding and, in a certain sense, unique, working conditions of general practitioners (GPs) are characterized by two phenomena: First, they involve an increasing familiarity with individual patients over time, which promotes a deepening of insight. Second, they enable the GP to encounter all kinds of health problems, which in turn facilitates pattern recognition, at both individual and group levels, particularly the kind of patterns currently termed "multimorbidity." Whereas the term "comorbidity" is used to denote states of bad health in which 1 disease is considered to predate and evoke other ailments or diseases, the term multimorbidity is applied when finding several presumably separate diseases in a person who suffers from them either sequentially or simultaneously. Encounters with patients whose suffering fits the biomedical concept and terminology of multimorbidity are among the most common which GPs face, presenting them with some of their most demanding tasks. The term multimorbidity needs to be examined, however. As it alludes to a multiplicity of diseases, it rests on an assumption of separateness of states of bad health that might not be well founded. An adequate determination of what to deem a "separate" state of bad health would require that the biomedical concept of causation be scrutinized.

Social determinants and BCG efficacy: a call for a socio-biological approach to TB prevention

A high burden of TB mortality persists despite the long-term availability of the bacillus Calmette-Guérin (BCG) vaccine, whose efficacy has been highly variable across populations. Innovative and alternative approaches to TB prevention are urgently needed while optimal biomedical tools continue to be developed. We call for new interdisciplinary collaborations to expand and integrate our understanding of how social determinants influence the biological processes that lead to TB disease, how this translates into differential BCG efficacy and, ultimately, how social protection interventions can play a role in reducing the global burden of TB. After providing an overview of the immune pathways important for the establishment of a response to the BCG vaccine, we outline how social determinants and psychosocial stressors can contribute to the observed variation in BCG efficacy above and beyond these biological factors. We conclude by proposing a new interdisciplinary research model based on the integration of social epidemiology theories with biomedical knowledge.

Psychoneuroimmunology-developments in stress research

Links between the central nervous stress system and peripheral immune cells in lymphoid organs have been detailed through 50 years of intensive research. The brain can interfere with the immune system, where chronic psychological stress inhibits many functions of the immune system. On the other hand, chronic peripheral inflammation-whether mild (during aging and psychological stress) or severe (chronic inflammatory diseases)-clearly interferes with brain function, leading to disease sequelae like fatigue but also to overt psychiatric illness. In recent years, it has been observed that psychological stress can be disease permissive, as in chronic inflammatory diseases, cancer, cardiovascular diseases, acute and chronic viral infections, sepsis, asthma, and others. We recognized that stress reactivity is programmed for a lifetime during a critical period between fetal life and early childhood, which then influences stress behavior and stress responses in adulthood. First phase II clinical studies, e.g., on cognitive behavioral therapy and mind-body therapies (e. g., mindfulness-based stress reduction), are available that show some benefits in stressful human diseases such as breast cancer and others. The field of psychoneuroimmunology has reached a firm ground and invites therapeutic approaches based on Good Clinical Practice phase III multicenter randomized controlled trials to influence stress responses and outcome in chronic illness.

Restraint and Social Isolation Stressors Differentially Regulate Adaptive Immunity and Tumor Angiogenesis in a Breast Cancer Mouse Model

The ability of stress to induce immune suppression is widely recognized, but the mechanisms underlying the effects of stress on the adaptive immune system during tumor progression are not completely understood. To study the effect of stress on the immune system in vivo, we used a preclinical immunocompetent mouse model bearing 4T1 mammary adenocarcinoma cells. Mice were randomized into 4 groups, including social isolation (SI), acute restraint stress (aRRS), chronic restraint stress (cRRS), or no stress (NS). We found that SI significantly decreased the number of tumor-bearing mice still alive at the end of protocol (28 days), compared to NS mice. Although we did not detect significant changes in primary tumor volume, we observed a significant increase in the endothelial marker CD31 in primary tumors of SI mice and in lung metastases in SI and RRS mice. Survival decline in SI mice was associated with significant decreases in splenic CD8 cells and in activated T cells. From a mechanistic standpoint, RRS increased expression of FOXP3, CXCL-10, and granzyme B in mouse tumors, and the effects were reversed by propranolol. Our data demonstrate that various forms of stress differentially impact adaptive immunity and tumor angiogenesis, and negatively impact survival.

The Signature of Maternal Social Rank in Placenta Deoxyribonucleic Acid Methylation Profiles in Rhesus Monkeys

The effects of social status on human health can be modeled in captive cohorts of nonhuman primates. This study shows that maternal social rank is associated with broad changes in DNA methylation in placentae of rhesus monkeys (N = 10). Differentially methylated genes between social ranks are enriched in signaling pathways playing major roles in placenta physiology. Moreover, the authors found significant overlaps with genes whose expression was previously associated with social rank in adult rhesus monkeys (Tung et al., 2012) and whose methylation was associated with perinatal stress in newborn humans and rhesus monkeys (Nieratschker et al., 2014). These results are consistent with the hypothesis that system-wide epigenetic changes in multiple tissues are involved in long-term adaptations to the social environment.

Social affiliation matters: both same-sex and opposite-sex relationships predict survival in wild female baboons

Social integration and support can have profound effects on human survival. The extent of this phenomenon in non-human animals is largely unknown, but such knowledge is important to understanding the evolution of both lifespan and sociality. Here, we report evidence that levels of affiliative social behaviour (i.e. 'social connectedness') with both same-sex and opposite-sex conspecifics predict adult survival in wild female baboons. In the Amboseli ecosystem in Kenya, adult female baboons that were socially connected to either adult males or adult females lived longer than females who were socially isolated from both sexes--females with strong connectedness to individuals of both sexes lived the longest. Female social connectedness to males was predicted by high dominance rank, indicating that males are a limited resource for females, and females compete for access to male social partners. To date, only a handful of animal studies have found that social relationships may affect survival. This study extends those findings by examining relationships to both sexes in by far the largest dataset yet examined for any animal. Our results support the idea that social effects on survival are evolutionarily conserved in social mammals.

Race/ethnic and socioeconomic differences in stress and immune function in The National Longitudinal Study of Adolescent Health

Stress and immune function may be important mediators of the strong association between social factors and health over the life course, but previous studies have lacked the data to fully explore these links in a population-based sample. This study utilizes data from Waves I-IV of the U.S. National Longitudinal Study of Adolescent Health (Add Health) to test the associations of race/ethnicity and socioeconomic status (SES) with levels of perceived stress and exposure to stressful life events (SLE) among 11,050 adult respondents aged 24-32 in 2008-2009. We further tested whether race/ethnicity and SES were associated with Epstein-Barr Virus (EBV) specific IgG antibodies, an indirect marker of cell-mediated immune function. Finally, we tested whether measures of stress were associated with EBV IgG and whether there was evidence that they explain any associations between race/ethnicity, SES and EBV IgG. We found strong associations between lower SES and higher levels of perceived stress (OR 2.07, 95% CI 1.73-2.48 for < high school vs. college or above) and a high level of stressful life events (OR 7.47, 95% CI 5.59-9.98 for < high school vs. college or above). Blacks had higher odds of a high level of stressful life events compared to whites (OR 2.00, 95% CI 1.63-2.47), but not higher perceived stress (OR 1.11, 95% CI 0.96-1.28). Blacks also had significantly higher EBV levels compared to whites (β = 0.136, p < 0.01), but lower SES was not associated with higher EBV IgG. We found no evidence that stressful life events or perceived stress were associated with EBV IgG in this sample, and thus did not account for racial differences in EBV IgG. These results suggest consistent race/ethnic and SES differences in stressful life events, and confirm race/ethnic differences in markers of immune function that may have health implications across the life course.

Annual research review: The neuroinflammation hypothesis for stress and psychopathology in children--developmental psychoneuroimmunology

Experimental animal and adult human data suggest that stress exposure is associated with alterations in immune system function that may underlie increased susceptibility to disease and behavioral disorders. The implications of these data for child psychology and psychiatry are not yet clear. The current review seeks to distil and translate the relevant animal and adult human work to children to advance a developmental model of psychoneuroimmunology. In addition to reviewing key specific findings, we consider biological/conceptual models and technical aspects of psychoneuroimmunology work in pediatric populations, and outline the rationales and advantages of integrating hypotheses concerning neuroinflammation in developmental studies of psychopathology.

"Anatomy of an Illness": control from a caregiver's perspective

Caregivers of loved ones with chronic illnesses experience an uncontrollable challenge with potentially negative behavioral and medical consequences. Extensive research has demonstrated immune and endocrine regulation can be significantly disrupted by negative behavioral factors based on both animal models and human studies. However, fewer studies have focused on how psychosocial interventions might reverse the negative consequences of stressors such as caregiving. The distress of caring for individuals with cancer has only recently begun to receive attention. These interventions addressing caregiver distress are rare overall and caregivers of patients receiving hematopoietic stem cell transplants (HSCT) have received even less attention. HSCT caregivers report feelings of loss of control. Animal studies suggest that control over aversive events can mitigate the negative consequences of stressors. Caregivers of allogeneic HSCT patients for blood cancers must be available 24/7 for three months or longer following stem cell infusion to closely monitor the recipients' health and well-being. Does establishing a greater sense of control have positive impacts on caregivers? A randomized control trial of a cognitive behavioral stress management intervention for allogeneic HSCT caregivers is briefly described. A model of caregiver mental health which may potentially impact the patient's quality of life is proposed. These relationships exist in a complex system that includes genetic influences, sex, social environment, and prior experience. This system fits well within recent formulations of a "complexity science" approach to health and well-being.

The influences of perinatal challenge persist into the adolescent period in socially housed bonnet macaques (Macaca radiata)

Social challenges during the perinatal period influence the mother-infant relationship in nonhuman primates and may affect the offspring's response to later social challenge(s). Relocation of a breeding colony of monkeys (Macaca radiata) created two groups of infants: one group experienced social group relocation to a new housing facility during the perinatal period (ATYPICAL) and the second group developed within a constant environment (TYPICAL). At a mean age of 25 months, all animals were removed from their natal group and placed in same sex adolescent social groups. Behavioral observations were collected after group formation or introduction to a new group. ATYPICAL subjects showed increased aggression and reduced affiliation compared to TYPICAL subjects. Hair cortisol in male subjects collected 6 months after introduction was elevated in the ATYPICAL subjects compared to TYPICAL subjects. These findings demonstrate that early life challenges affect behavior as well as stress hormone responses to social challenge in adolescence.

Effects of acute psychosocial stress in a nonhuman primate model of allergic asthma

Current husbandry and care guidelines for laboratory animals recommend social housing for nonhuman primates and all other social species. However, not all individuals of a social species are compatible, which can lead to psychosocial stress on certain members. Because stress affects immune responses, we undertook the present study to determine whether psychosocial stress associated with changes in the group housing of nonhuman primates affected allergic responses in a nonhuman primate model of allergic asthma. Historic records from 35 cynomolgus macaques (Macaca fascicularis) sensitive to house dust mites (HDM) and enrolled in asthma studies from 2007 to 2011 were reviewed for variations in response to aerosolized HDM that could not be explained by clinical or experimental interventions. We then compared these variations with husbandry and clinical records to determine whether the unexplained variations in responses were associated with events known to induce psychosocial stress in this species, including restructuring of social groups, temporary isolation of group members, and changes in cage or room configurations. Adult macaques in stable social groups exhibited little variation in responses to aerosolized antigen. Changes in group membership (conspecifics), cage configurations, and temporary isolation of a group member were associated with decreased responses to HDM. This attenuation lasted 2 to 3 mo on average, although some macaques showed prolonged responses. No evidence for a stress-induced increase in allergic responses was noted. These results demonstrate that acute stress in HDM-sensitive cynomolgus macaques diminishes the physiologic response to inhaled allergen.

Inflammatory vulnerability associated with the rh5-HTTLPR genotype in juvenile rhesus monkeys

Individual variation in serotonergic function is associated with reactivity, risk for affective disorders, as well as an altered response to disease. Our study used a nonhuman primate model to further investigate whether a functional polymorphism in the promoter region for the serotonin transporter gene helps to explain differences in proinflammatory responses. Homology between the human and rhesus monkey polymorphisms provided the opportunity to determine how this genetic variation influences the relationship between a psychosocial stressor and immune responsiveness. Leukocyte numbers in blood and interleukin-6 (IL-6) responses are sensitive to stressful challenges and are indicative of immune status. The neutrophil-to-lymphocyte ratio and cellular IL-6 responses to in vitro lipopolysaccharide stimulation were assessed in 27 juvenile male rhesus monkeys while housed in stable social groups (NLL  = 16, NS  = 11) and also in 18 animals after relocation to novel housing (NLL  = 13, NS  = 5). Short allele monkeys had significantly higher neutrophil-to-lymphocyte ratios than homozygous Long allele carriers at baseline [t(25) = 2.18, P = 0.02], indicative of an aroused state even in the absence of disturbance. In addition, following the housing manipulation, IL-6 responses were more inhibited in short allele carriers (F1,16  = 8.59, P = 0.01). The findings confirm that the serotonin transporter gene-linked polymorphism is a distinctive marker of reactivity and inflammatory bias, perhaps in a more consistent manner in monkeys than found in many human studies.

Commentary on the symposium: biological embedding, life course development, and the emergence of a new science

A new science of human development is emerging, which has the capacity to transform the way we understand the origins of health and disease; to increase the public health significance of early child development; and to call into question how and when society should act on a range of health problems. It builds on the multidisciplinary evidence that social environments and experiences during sensitive periods in brain and biological development affect health for the balance of the life course through a process called biological embedding. Despite the fact that biological embedding has established credibility in the scientific literature, the transformative power of the new science has yet to be fully realized in policy and practice. To further this transformation, this symposium offers a public health perspective on biological embedding.

A life course model of self-rated health through adolescence and young adulthood

This paper proposes and tests a life course model of self-rated health (SRH) extending from late childhood to young adulthood, drawing on three waves of panel data from the National Longitudinal Study of Adolescent Health (Add Health). Very little research has examined SRH during the early decades, or whether and how these self-assessments reflect experiences in the family of origin. Background characteristics (parental education, income, and family structure), parental health conditions (asthma, diabetes, obesity, migraines), and early health challenges (physical abuse, presence of a disability, and parental alcoholism and smoking) predict SRH from adolescence to young adulthood. These experiences in the family-of-origin are substantially mediated by the young person's health and health behaviors (as indicated by obesity, depression, smoking, drinking, and inactivity), although direct effects remain (especially for early health challenges). Associations between SRH and these mediators (especially obesity) strengthen with age. In turn, efforts to promote healthy behaviors in young adulthood, after the completion of secondary school, may be especially strategic in the promotion of health in later adulthood.

Chronic stress, allostatic load, and aging in nonhuman primates

Allostatic load is the "wear and tear" of the body resulting from the repeated activation of compensatory physiological mechanisms in response to chronic stress. Allostatic load can significantly affect the aging process and result in reduced longevity, accelerated aging, and impaired health. Although low socioeconomic status is associated with high allostatic load during aging, the effects of status-related psychosocial stress on allostatic load are often confounded by lifestyle variables. Chronic psychosocial stress associated with low dominance rank in nonhuman primates represents an excellent animal model with which to investigate allostatic load and aging in humans. Research conducted with free-ranging rhesus monkeys suggests that female reproduction can also be a source of stress and allostatic load. Female reproduction is associated with increased risk of mortality and hyperactivation of the hypothalamic-pituitary-adrenal axis. Reproduction is especially stressful and costly for aging females of low rank. Although many indicators of body condition and neuroendocrine and immune function are influenced by aging, there are marked and stable individual differences among aging females in body condition, plasma cortisol responses to stress, and cytokine responses to stress. These differences are consistent with the hypothesis that there are strong differences in chronic stress among individuals, and that allostatic load resulting from chronic stress affects health during aging. Comparisons between captive and free-ranging rhesus monkey populations may allow us to understand how differences in environmental stress and allostatic load affect rates of aging, and how these in turn translate into differences in longevity and health.

Family poverty is associated with cytomegalovirus antibody titers in U.S. children

OBJECTIVE

Early life environmental and psychological influences are thought to play an important role in the development of the immune system. Antibody response to latent herpesviruses has been used as an indirect measure of cell-mediated immune function but has seldom been applied to younger age groups.

METHODS

We used data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES) to test for an association between family poverty and continuous antibody response to cytomegalovirus in U.S. children aged 6-16 (N = 2,226) using ordinary least squares regression.

RESULTS

Poverty was significantly associated with increased antibody levels among seropositive individuals. The association between income and antibody levels exhibited a threshold effect, with additional income beyond the poverty line not associated with increased antibody titers. This relationship was more robust among older compared with younger children.

CONCLUSIONS

Early life social factors such as family poverty could have detrimental impacts on the developing immune system, with potentially important consequences for later life health outcomes. Exposure to socioeconomic stressors for longer periods during childhood may further enhance alterations in immune response to cytomegalovirus.

Allostatic processes in the family

The concepts of allostatic load and allostatic processes can help psychologists understand how health trajectories are influenced by stressful childhood experiences in the family. This paper describes psychological pathways and two key allostatic mediators, the hypothalamic–pituitary–adrenal axis and the immune system, through which stressful early rearing conditions may influence adult mental and physical health. The action of meshed gears is introduced as a metaphor to illustrate how responses occurring within a brief time frame, for example, immediate reactions to stressors, can influence developmental and health processes unfolding over much longer spans of time. We identify early-developing psychological and biological response patterns that could link chronic stressors in childhood to later health outcomes. Some of these “precursor outcomes” (e.g., heightened vigilance and preparedness for threats; enhanced inflammatory and humoral responses to infectious microorganisms) appear to be aimed at protection from immediate dangers; they may reflect “adaptive trade-offs” that balance short-term survival advantages under harsh rearing conditions against disadvantages manifested later in development. Our analysis also suggests mechanisms that underlie resilience in risky family environments.

Traumatic brain injury in intimate partner violence: a critical review of outcomes and mechanisms

The prevalence of intimate partner violence (IPV) is striking, as are its consequences to the lives of women. The IPV often includes physical assault, which can include injuries to the head and attempted strangulation injuries. Both types of injuries can result in traumatic brain injury (TBI). The TBI sustained during IPV often occurs over time, which can increase the risk for health declines and postconcussive syndrome (PCS). Current studies have identified sequelae of cognitive dysfunction, posttraumatic stress disorder, and depression in women experiencing IPV, yet, most fail to determine the role of TBI in the onset and propagation of these disorders. Although imaging studies indicate functional differences in neuronal activation in IPV, they also have not considered the possibility of TBI contributing to these outcomes. This review highlights the significant gaps in current findings related to neuropsychological complications and medical and psychosocial symptoms that likely result in greater morbidity, as well as the societal costs of failing to acknowledge the association of IPV and TBI in women.

Language and cognitive outcomes in internationally adopted children

This study focuses on the association between language skills and core cognitive processes relative to the duration of institutionalization in children adopted from orphanages abroad. Participants in the adoptive group (n = 46) had arrived in the United States between the ages of 2 and 84 months (mean = 24 months), and had been living in the United States for 1–9 years. Drawing on both experimental and standardized assessments, language skills of the international adoptees differed as a function of length of time spent in an institution and from those of 24 nonadopted controls. Top-down cognitive assessments including measures of explicit memory and cognitive control differed between adopted and nonadopted children, yet differences between groups in bottom-up implicit learning processes were unremarkable. Based on the present findings, we propose a speculative model linking language and cognitive changes to underlying neural circuitry alterations that reflect the impact of chronic stress, due to adoptees' experience of noncontingent, nonindividualized caregiving. Thus, the present study provides support for a relationship between domain-general cognitive processes and language acquisition, and describes a potential mechanism by which language skills are affected by institutionalization.

Estimates of milk constituents from lactating bonnet macaque (Macaca radiata) mothers between two and seven months post-partum

BACKGROUND

The literature regarding milk composition in non-human primates collected across offspring development is limited. We assayed milk samples from bonnet macaque (Macaca radiata) mothers as part of studies characterizing development of this species.

METHODS

Milk was obtained when possible longitudinally from seven lactating bonnet macaque mothers. Samples were frozen until analysis. Individual samples were analyzed to determine the concentrations of electrolytes including sodium, potassium, calcium, chloride, and magnesium, as well as urea, protein, lipids, glucose, and lactose.

RESULTS

A trend for increased lipids as well as protein percentage was noted with increasing infant age. Chloride and calcium showed an increase with age, whereas other electrolytes remained relatively stable across development.

CONCLUSIONS

The composition of the milk of this particular macaque species was similar to other Old World primates as well as humans. These data add to the limited information available on milk constituents among mammals.

Challenges to bonnet monkey (Macaca radiata) social groups: Mother-infant dyad and infant social interactions

The mother-infant dyad is crucial to early development in a variety of species. The complexity of social groupings in nonhuman primates makes this relationship resilient as well as susceptible to early challenges associated with environmental chaos. Quantitative behavior observations of bonnet monkey mother-infant interactions were collected from 28 mother-infant dyads between one and twelve months of age. Social groups were subjected to several prenatal and/or postnatal housing relocations within a single year resulting in two study groups. One group experienced relocations (ATYPICAL, n = 14) and the second group (TYPICAL, n = 14) was conceived and reared in the same location. Behaviors in the ethogram included mother-infant interactions and infant social interactions with other members of the group. Observations between ages of two to four months were analyzed by a mixed model analysis of variance including fixed effects of per and postnatal history (TYPICAL, ATYPICAL), age, and history by age interaction and random effects of mother and infant nested within mother. A significant effect of relocation history was noted on a number of infant behaviors. ATYPICAL infants were out of direct contact with their mother at an earlier age but remained in her proximity. Control of proximity shifted to offsrping in the ATYPICAL group compared to the TYPICAL group. Furthermore, greater social interactions between two and four months of age with other members of the social group as well as the ir mother were observed in the ATYPICAL group. It is suggested that continuous challenge associated with relocation may affect the infant at later developmental ages due to these early differences in ways that are yet unclear.

Effects of psychological stress and fluoxetine on development of oral candidiasis in rats

Psychological stress has been found to suppress cell-mediated immune responses that are important for limiting the proliferation of Candida albicans. Fluoxetine has been observed to reduce negative consequences of stress on the immune system in experimental and clinical models, but there are no data on its effects on oral candidiasis. We designed experiments to evaluate the effects of fluoxetine on the development of oral candidiasis in Sprague-Dawley rats exposed to a chronic auditory stressor. Animals were submitted to surgical hyposalivation in order to facilitate the establishment and persistence of C. albicans infection. Stress application and treatment with drugs (placebo or fluoxetine) were initiated 7 days before C. albicans inoculation and lasted until the end of the experiments, on day 15 postinoculation. Establishment of C. albicans infection was evaluated on days 2 and 15 after inoculation. Tissue injury was determined by the quantification of the number and type (normal or abnormal) of papillae on the dorsal tongue per microscopic field. A semiquantitative scale was devised to assess the degree of colonization of the epithelium by fungal hyphae. Our results showed that stress exacerbates C. albicans infection in the tongues of rats. Significant increases in Candida counts, the percentage of the tongue's surface covered with clinical lesions, the percentage of abnormal papillae, and the colonization of the epithelium by hyphae were found in stressed rats compared to the nonstressed ones. Treatment with fluoxetine significantly reversed these adverse effects of stress. Besides the psychopharmacological properties of fluoxetine against stress, it has consequences for Candida infection.

Surgical stress-induced immune cell redistribution profiles predict short-term and long-term postsurgical recovery. A prospective study

BACKGROUND

The experience of undergoing surgery is known to induce a short-term, fight-or-flight physiological stress response. As an optimum immune response at the site of surgery would enhance tissue repair, we examined surgical stress-induced immune cell redistribution profiles as predictors, and potential mediators, of short and long-term postoperative recovery. We tested the a priori hypothesis that predefined adaptive immune cell redistribution profiles observed during surgery will predict enhanced postoperative recovery.

METHODS

This prospective longitudinal study involved fifty-seven patients undergoing meniscectomy. Knee function was assessed preoperatively and at one, three, eight, sixteen, twenty-four, and forty-eight weeks postoperatively with use of the clinically validated Lysholm scale, which assesses mechanical function, pain, mobility, and the ability to perform daily activities. Surgery-induced immune cell redistribution was measured in the blood at baseline, before surgery, and after surgery.

RESULTS

Mixed-model repeated-measures analyses revealed a main effect of immune cell redistribution: patients who showed the predefined "adaptive" lymphocyte and monocyte redistribution profiles during surgery showed enhanced recovery. Interesting differences were also observed between the sexes: women as a group showed less adaptive redistribution and correspondingly showed significantly delayed maximum recovery, requiring forty-eight weeks, compared with men, who required only sixteen weeks. Inter-individual differences in leukocyte redistribution predicted the rate of recovery across both sexes.

CONCLUSIONS

Immune cell redistribution that is induced by the stress of undergoing surgery can predict (and may partially mediate) postoperative healing and recovery. These findings may provide the basis for identifying patients (either prospectively or during surgery) who are likely to show good as opposed to poor recovery following surgery and for designing interventions that would maximize protective immune responses and enhance the rate and extent of recovery.

When is enough measurement, enough? Generalizability of primate immunity over time

A statistical generalizability analysis gauges the degree to which a single assessment of a parameter successfully estimates that measure over repeated assessments for that individual. The generalizability of enumerative and functional immune parameters was estimated for two species of macaque monkeys assessed every 3 months between 18 and 42 months of age. Subjects were cross-balanced by species (bonnet, Macaca radiata, n=22; pigtail, Macaca nemestrina, n=21), sex (male, n=21; female, n=22), and brief early maternal separation with reunion (control, n=21; separated, n=22). Cell subset analysis showed the best generalizability (35-69%). Natural cytotoxicity also performed well (44-70%), but when computed on a lysis per cell basis, removing the effect of cell phenotype, it was less stable (15-48%). For most immune parameters, at least 5 assessments would be necessary to establish conventionally reliable (0.80) characterizations of long-term, stable individual differences in immunity, and three for minimally reliable (0.60) characterizations. More reactive parameters, as well as more behaviorally reactive species, yielded more generalizable results. Cell subsets that are typically most sensitive to acute stress (CD8, CD16) were more stable than other subsets (CD4, CD20). Behaviorally reactive species (pigtail) yielded more stable natural cytotoxicity results than the less reactive species (bonnet). Sex and rearing condition (early, brief maternal separation) did not substantially affect generalizability, although females tended to generate more stable results than did males.

Practitioner empathy and the duration of the common cold

OBJECTIVE

This study's objective was to assess the relationship of empathy in medical office visits to subsequent outcomes of the common cold.

METHODS

A total of 350 subjects ? 12 years of age received either a standard or enhanced physician visit as part of a randomized controlled trial. Enhanced visits emphasized empathy on the part of the physician. The patient-scored Consultation and Relational Empathy (CARE) questionnaire assessed practitioner-patient interaction, especially empathy. Cold severity and duration were assessed from twice-daily symptom reports. Nasal wash was performed to measure the immune cytokine interleukin-8 (IL-8).

RESULTS

Eighty-four individuals reported perfect (score of 50) CARE scores. They tended to be older with less education but reported similar health status, quality of life, and levels of optimism. In those with perfect CARE scores, cold duration was shorter (mean 7.10 days versus 8.01 days), and there was a trend toward reduced severity (mean area under receiver-operator characteristics curve 240.40 versus 284.49). After accounting for possible confounding variables, cold severity and duration were significantly lower in those reporting perfect CARE scores. In these models, a perfect score also correlated with a larger increase in IL-8 levels.

CONCLUSIONS

Clinician empathy, as perceived by patients with the common cold, significantly predicts subsequent duration and severity of illness and is associated with immune system changes.

Gender, race/ethnicity, personality, and interleukin-6 in urban primary care patients

Gender, race/ethnicity, and personality are markers of significant psychosocial and biological variability. Each may have implications for allostatic load and resulting inflammatory processes, yet findings have been largely mixed. We investigated whether women, minorities, and those higher in Neuroticism and lower in Extraversion were at risk for elevated circulating levels of the pro-inflammatory cytokine interleukin (IL)-6 in a sample of 103 middle aged and older urban primary care patients. Regression analyses controlling for age, education, current depression levels, and chronic medical conditions revealed that women, minorities, and individuals lower in Extraversion had higher circulating levels of IL-6. Analyses of more specific personality traits revealed that the sociability and positive emotions components of Extraversion were unassociated with IL-6, but the activity facet-reflecting dispositional vigor and energy-was robustly associated with IL-6. The difference between high (+1 Standard Deviation (SD)) and low (-1 SD) trait activity was sufficient to shift IL-6 levels beyond a previously established high risk cut-point in both white and minority women. These findings suggest that while broad group differences between genders and races/ethnicities exist, personality represents an important source of individual differences in inflammation within groups. Future work should examine to what extent IL-6 levels are linked to temperament or genetic activity levels vs. physical activity itself, and whether IL-6 levels may be reduced by boosting regular activity levels in demographic segments such as women and minorities who appear susceptible to greater inflammation.

Psychologically adverse work conditions are associated with CD8+ T cell differentiation indicative of immunesenescence

Numerous studies have demonstrated associations between psychosocial stress and indices of poor health, and much research is now dedicated to identifying the responsible biological mechanisms. The current study examined the hypothesis that stress may impact health by promoting immunesenescence. Participants were 537 factory workers (89% male; mean age 44; range 18-65years). Blood was analyzed for two components of the aging 'immune risk phenotype': the number and proportion of late-differentiated (CD27-CD28-) CD8 T cells (CTLs) and CD4:CD8 ratio. Psychological assessment focussed on work-related stressors which have previously been found to predict morbidity and mortality. This assessment included measures of work load, effort-reward imbalance, and social support at work. High levels of job stress (low reward, high effort-reward imbalance) and low social support at work were associated with a significantly lower CD4:CD8 ratio. Also, the number of CD27-CD28- CTLs was 30% to 50% higher in employees classified in the highest tertile of each stress parameter as compared to employees in the corresponding lowest tertile (p<.01). These associations withstood adjustment for a wide range of demographic, life style, medical, and socio-economic indicators. The associations between CTL phenotype and low social support became stronger with increasing age. These results suggest that psychosocial stress may contribute to immunological aging. Prospective studies should address the long-term consequences of these associations for healthy aging.

From psychosomatic to psychological medicine: what's the future?

PURPOSE OF REVIEW

Recent research findings into putative psychobiological mechanisms of emotional disorders as the future development of psychosomatic medicine are discussed.

RECENT FINDINGS

Recent studies reinforce the communication between the immune and central nervous systems and identify the large set of peptide and nonpeptide neurotransmitters and ligands they share. Cytokines are seen as humoral mediators that may explain the interaction between endocrine and immune systems. The hypothalamic-pituitary axis has been investigated as part of the regulatory circuits that interact with autonomic regulation to expose immunologic processes related to stress or depression, and also to several diseases. Immune dysregulation and psychological distress have been linked to each other in disease, chronic stress, bereavement and other major life events. Research findings in depressive disorders and cancer may generate new theoretical paradigms in psychosomatic medicine.

SUMMARY

The clinical understanding and management of distress or emotional disorders associated with physical illness may change in future because of the results of interdisciplinary research, where environmental factors will be integrated with psychological and biological systems, mainly of endocrine or neuroimmunological nature. The ultimate goal of psychosomatic medicine may be the integration of different levels of individual functioning on a systemic basis.