Social regulation of leukocyte homeostasis: the role of glucocorticoid sensitivity

Can social adversity alter the epigenome, trigger oral disease, and affect future generations?

The nature versus nurture debate has intrigued scientific circles for decades. Although extensive research has established a clear relationship between genetics and disease development, recent evidence has highlighted the insufficiency of attributing adverse health outcomes to genetic factors alone. In fact, it has been suggested that environmental influences, such as socioeconomic position (SEP), may play a much larger role in the development of disease than previously thought, with extensive research suggesting that low SEP is associated with adverse health conditions. In relation to oral health, a higher prevalence of caries (tooth decay) exists among those of low SEP. Although little is known about the biological mechanisms underlying this relationship, epigenetic modifications resulting from environmental influences have been suggested to play an important role. This review explores the intersection of health inequalities and epigenetics, the role of early-life social adversity and its long-term epigenetic impacts, and how those living within the lower hierarchies of the socioeconomic pyramid are indeed at higher risk of developing diseases, particularly in relation to oral health. A deeper understanding of these mechanisms could lead to the development of targeted interventions for individuals of low SEP to improve oral health or identify those who are at higher risk of developing oral disease.

Social Determinants of Health in Cardio-Oncology: Multi-Level Strategies to Overcome Disparities in Care: JACC: CardioOncology State-of-the-Art Review

Addressing the need for more equitable cardio-oncology care requires attention to existing disparities in cardio-oncologic disease prevention and outcomes. This is particularly important among those affected by adverse social determinants of health (SDOH). The intricate relationship of SDOH, cancer diagnosis, and outcomes from cardiotoxicities associated with oncologic therapies is influenced by sociopolitical, economic, and cultural factors. Furthermore, mechanisms in cell signaling and epigenetic effects on gene expression link adverse SDOH to cancer and the CVD-related complications of oncologic therapies. To mitigate these disparities, a multifaceted strategy is needed that includes attention to health care access, policy, and community engagement for improved disease screening and management. Interdisciplinary teams must also promote cultural humility and competency and leverage new health technology to foster collaboration in addressing the impact of adverse SDOH in cardio-oncologic outcomes.

Contributions of loneliness to cognitive impairment and dementia in older adults are independent of other risk factors and Alzheimer's pathology: a narrative review

Loneliness significantly contributes to cognitive impairment and dementia in older adults. Loneliness is a distressing feeling resulting from a perceived lack of social connection (i.e., a discrepancy between desired and actual social relationships), while social isolation is a related term that can be defined by number and type of social relationships. Importantly, loneliness is distinct from social isolation in that it is associated with a distressing self-perception. The primary focus of this narrative review is the impact of chronic loneliness on cognitive impairment and dementia among older adults. Loneliness has a significant association with many factors that are related to worse cognition, and therefore we include discussion on health, mental health, as well as the physiological effects of loneliness, neuropathology, and potential treatments. Loneliness has been shown to be related to development of dementia with a hazard ratio (HR) risk comparable to having a single APOE4 gene. The relationship of dementia to loneliness appears to be at least partially independent of other known dementia risk factors that are possibly associated with loneliness, such as depression, educational status, social isolation, and physical activity. Episodic memory is not consistently impacted by loneliness, which would be more typically impaired if the mild cognitive impairment (MCI) or dementia was due to Alzheimer's disease (AD) pathology. In addition, the several longitudinal studies that included neuropathology showed no evidence for a relationship between loneliness and AD neuropathology. Loneliness may decrease resilience, or produce greater cognitive change associated with the same level of AD neuropathology. Intervention strategies to decrease loneliness in older adults have been developed but need to consider key treatment targets beyond social isolation. Loneliness needs to be assessed in all studies of cognitive decline in elders, since it significantly contributes to the variance of cognitive function. It will be useful to better define the underlying mechanism of loneliness effects on cognition to determine if it is similar to other psychological factors related to excessive stress reactivity, such as neuroticism or even depression, which are also associated with cognitive decline. It is important from a health perspective to develop better strategies to decrease loneliness in older adults.

Neighborhood racial composition and experiences of racial discrimination: Associations with cytokines during pregnancy among African American women

Background

Preterm birth rates are consistently higher in African American (AA) pregnancies compared to White pregnancies in the United States. Neighborhood racial composition, experiences of racial discrimination, and systemic inflammation are factors that have been associated with preterm birth and other adverse pregnancy outcomes that may account for these disparities. Here, we investigated whether perceived neighborhood racial composition and experiences of discrimination were predictive of cytokine levels during pregnancy among AA individuals.

Methods

545 AA individuals completed surveys and had blood samples collected at prenatal clinics in the Midwest at three timepoints (8-18,19-29, and 30-36 weeks gestation) throughout pregnancy. Pro-inflammatory [interferon (IFN)-γ, interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, macrophage migration inhibitory factor (MIF)] and anti-inflammatory cytokines (IL-10) were quantified. Multivariate and multilevel models were used to examine associations of perceived neighborhood racial composition and experiences of racial discrimination with cytokine levels, controlling for relevant covariates.

Results

Perceived neighborhood racial composition was significantly associated with MIF at 30-36 weeks gestation in multivariate regression (p < 0.001). Living in neighborhoods with more compared to fewer White people was predictive of higher levels of MIF (b = 0.599, SE = 0.12, p < 0.001). Experiences of discrimination were also associated with higher levels of MIF (β = 0.141, SE = 0.07, p = 0.036). Neither predictor was associated with other cytokines. Follow-up analyses revealed that neighborhood racial composition was also predictive of higher MIF levels at 8-18 weeks gestation (p = 0.02) and at 19-29 weeks gestation (p = 0.04).

Conclusions

Living in neighborhoods with more White individuals and having more lifetime experiences of racial discrimination were positively related to levels of the pro-inflammatory cytokine, MIF, among pregnant AA individuals. MIF's known positive relationships with chronic stress and preterm birth suggest that these elevations in MIF may have negative health consequences. Future studies should explore whether MIF serves as a pathway between neighborhood racial composition or experiences of racial discrimination and preterm birth risk among AA individuals.

Loneliness, immunological recovery patterns, and health-related quality of life (HRQOL) outcomes in patients receiving hematopoietic stem cell transplantation

PURPOSE

Loneliness may compromise health-related quality of life (HRQOL) outcomes and the immunological impacts of loneliness via neuroendocrinological mechanisms likely have consequences for patients who have undergone a hematopoietic stem cell transplantation (HSCT).

RESEARCH APPROACH AND MEASURES

Loneliness (pre-transplant), immunological recovery (Day 30, Day 100, 1-year post-transplant), and HRQOL (Day 100, 1 year) were measured in a sample of 205 patients completing a HSCT (127 autologous, 78 allogenic).

RESULTS

Greater levels of pre-transplant loneliness predicted poorer HRQOL at Day 100 and 1-year follow-up. Loneliness also was associated with higher absolute neutrophil to absolute lymphocyte (ANC/ALC) ratios in the entire sample at Day 30, which in turn was associated with Day 100 HRQOL.

CONCLUSIONS

Findings demonstrate that pretransplant loneliness predicts HRQOL outcomes and associates with inflammatory immunological recovery patterns in HSCT patients. The balance of innate neutrophils to adaptive lymphocytes at Day 30 present a distinct profile in lonely individuals, with this immunity recovery profile predicting reduced HRQOL 100 days after the transplant. Addressing perceptions of loneliness before HSCT may be an important factor in improving immunological recovery and HRQOL outcomes.

Metabolic syndrome in adults with autistic traits: associated psychological, behavioral, and biological factors in females and males - a PharmLines initiative

Background

While cardiovascular diseases is highly prevalent and an important cause of mortality in autistic adults, knowledge on their increased cardiovascular risk is limited. Hence, this study aimed to investigate psychological, behavioral, and physical factors associated with metabolic syndrome (MetS) in adults with autistic traits.

Methods

In total, 17,705 adults from the Lifelines Cohort were included and categorized using Autism Spectrum Quotient-10 sum-scores. The quartiles with highest (HQ-traits-group females: n = 2,635; males: n = 1803) and lowest levels of autistic traits (LQ-traits-group, n = idem) were analyzed. Using multivariable logistic regression, the associations between MetS and (self-reported and interviewed) psychological, behavioral, and physically measured factors in these stratified groups were investigated.

Results

Among females, MetS was more common in the HQ-traits-group than in the LQ-traits-group (10.0% versus 7.5%, p < 0.01), while this was not the case among males (HQ-traits-group 13.8% versus LQ-traits-group 13.1%, p = 0.52). In both the female and male HQ-traits-group, the presence of MetS was associated with poorer self-reported health, less daily physical activity, and altered leukocyte counts.

Conclusion

These findings underline the relevance of adequate cardiovascular prevention in adults with higher levels of autistic traits. Future research could gain more insight into the relationship between cardiovascular risk and autistic traits in females, and into tailored cardiovascular prevention.

Increased Salivary IL-1 Beta Level Is Associated with Poor Sleep Quality in University Students

Poor sleep quality is a major public health concern for all ages. In particular, university students often face stress levels and changes in social life habits that negatively influence their quality of sleep. This could be associated with psychological well-being in terms of anxiety and depressive symptoms, stress levels, and a poor self-perceived health status. The increases in the pro-inflammatory cytokine interleukin 6 (IL-6), IL-1 beta (IL-1β), and tumor necrosis factor alpha (TNFα), in blood have been linked to poor sleep quality in many diseases, but data on salivary cytokine levels in students are missing or are seldom analyzed. In this study we determined the quality of sleep in a sample of university students and the role of psychological assessment and factors affecting sleep (alcohol intake, tobacco, consumption of stimulant drinks, exercise, and body mass index). We also aimed to shed new light on the associations between sleep quality and salivary inflammatory cytokines (IL-1β, IL-6, and TNFα). Sleep quality was measured with the Athens Insomnia Scale (AIS) and Pittsburgh Sleep Quality Index (PSQI). Perceived stress was assessed using Cohen's Perceived Stress Scale (PSS), and the Goldberg Anxiety and Depression Scale (GADS) was used to assess the level of anxiety or depression. Perceived health status was measured with a visual analogue. Saliva samples was taken in the morning and the inflammatory cytokines was measured via enzyme-linked immunoassay. There was a direct and significant association between the salivary IL-1β concentration and AIS score (r = 0.248; p = 0.038, Pearson correlation) and Pittsburgh scale score (r = 0.274; p = 0.022, Pearson correlation). The relationship between IL-1β and AIS controlling for sex, age, and chronic disease, is still significant (r = 0.260; p = 0.033). The relationship between IL-1β and PSQI controlling for the influence of these variables is also significant (r = 0.279; p = 0.022). Salivary IL-1β concentrations were not significantly associated with any of the scores of the other psychological assessments (PSS, anxiety, depression symptoms, or self-perceived health). Salivary TNFα was significantly and inversely associated with self-perceived health (r = -0.259; p = 0.033, Pearson correlation), but the salivary IL-6 concentration was not associated with any of the sleep quality scale or psychological assessment scores. Our results provide a novel relationship between pro-inflammatory cytokine IL-1β in saliva and poor sleep quality. However, the role of inflammation in poor sleep quality requires further study to identify strategies that could lower inflammation and thus, likely improve sleep quality.

Opportunities and Challenges of Kava in Lung Cancer Prevention

Lung cancer is the leading cause of cancer-related deaths due to its high incidence, late diagnosis, and limited success in clinical treatment. Prevention therefore is critical to help improve lung cancer management. Although tobacco control and tobacco cessation are effective strategies for lung cancer prevention, the numbers of current and former smokers in the USA and globally are not expected to decrease significantly in the near future. Chemoprevention and interception are needed to help high-risk individuals reduce their lung cancer risk or delay lung cancer development. This article will review the epidemiological data, pre-clinical animal data, and limited clinical data that support the potential of kava in reducing human lung cancer risk via its holistic polypharmacological effects. To facilitate its future clinical translation, advanced knowledge is needed with respect to its mechanisms of action and the development of mechanism-based non-invasive biomarkers in addition to safety and efficacy in more clinically relevant animal models.

Wealth, health and inequality in Agta foragers

Background and objectives

There is significant evidence from large-scale, industrial and post-industrial societies that greater income and wealth inequality is negatively associated with both population health and increasing health inequalities. However, whether such relationships are inevitable and should be expected to impact the health of small-scale societies as they become more market-integrated is less clear.

Methodology

Here, using mixed-effect models, we explore the relationship between health, wealth, wealth inequality and health inequalities in a small-scale foraging population from the Philippines, the Agta.

Results

Across 11 camps, we find small to moderate degrees of wealth inequality (maximal Gini Coefficient 0.44) which is highest in the most permanent camps, where individuals engage more heavily in the formal market. However, in both adults (n = 161) and children (n = 215), we find little evidence that either wealth or wealth inequality associates with ill health, except for one measure of nutritional condition-red blood cell count.

Conclusions and implications

We interpret these results in the light of high levels of cooperation among the Agta which may buffer against the detrimental effects of wealth inequality documented in industrial and post-industrial societies. We observe little intergenerational wealth transmission, highlighting the fluid nature of wealth, and thus wealth inequality, particularly in mobile communities. The deterioration of nutritional status, as indicated by red blood cell counts, requires further investigation before concluding the Agta's extensive cooperation networks may be beginning to breakdown in the face of increasing inequality.

Loneliness - Cancer of the Mind

World is greying as the proportion of the ageing population increases and the demography is changing both in the developing and developed world. Contact between people is the central part of everyone's life and the glue that holds communities and society together. Lack of social relations is considered to cause loneliness and isolation for the individual and, simultaneously, on a societal level, leads to marginalisation, social disintegration and diminishing trust between people. This has come to sharp focus during the corona pandemic. Meaningful social connections are central to the physical and mental health of human beings. Off late, the deleterious health implication of social isolation and loneliness has increasingly been noticed, with a higher risk of premature death and accelerated risks of coronary heart disease, stroke, depression, and dementia. Worldwide, there is an increasing awareness regarding the alarming consequences of loneliness, especially among older adults. In response, 2018 saw the launch of a UK loneliness strategy and the first minister for loneliness in the world appointed.

Variation in infant rhesus monkeys' (Macaca mulatta) neutrophil-to-lymphocyte ratio is associated with environmental conditions, emotionality, and cortisol concentrations, and predicts disease-related outcomes

The neutrophil-to-lymphocyte ratio (NLR) is a predictor of morbidity for a variety of medical conditions, but little is known about how variation in NLR arises. We examined variation in this measure in a sample of 4577 infant rhesus monkeys (54.8 % female), who participated in the BioBehavioral Assessment program at the California National Primate Research Center at 3-4 months of age. Lower values for NLR were seen for animals reared indoors, for animals that were raised to be free of specific pathogens, and for males. In addition lower NLR was associated with higher stress values of cortisol and with greater emotionality in response to an acute stressor. Finally, lower NLR in infancy was associated with greater risk for developing airways hyperresponsiveness (a hallmark of asthma); with display of diarrhea up to 3.97 years later; and with greater viral load when infected with the simian immunodeficiency virus at a mean of 6.1 years of age. Infant NLR was a better predictor of viral load than was a contemporaneously obtained measure of NLR. Infant and adult values of NLR were only modestly correlated; one reason may be that the infant measure was obtained during stressful conditions and the adult measure was obtained under baseline conditions. We propose that NLR is an integrated outcome measure reflecting organization and interaction of stress-response and immune systems. As such, assessment of NLR under conditions of stress may be a particularly useful marker of individual differences in morbidity, especially for conditions in which stress plays an important role, as in asthma, diarrhea/colitis, and AIDS.

Prognostic role of dynamic neutrophil-to-lymphocyte ratio in acute ischemic stroke after reperfusion therapy: A meta-analysis

Background

The prognostic role of the neutrophil-to-lymphocyte ratio (NLR), an inflammatory marker, in acute ischemic stroke (AIS) after reperfusion therapy remains controversial. Therefore, this meta-analysis sought to assess the correlation between the dynamic NLR and the clinical outcomes of patients with AIS after reperfusion therapy.

Methods

PubMed, Web of Science, and Embase databases were searched to identify relevant literature from their inception to 27 October 2022. The clinical outcomes of interest included poor functional outcome (PFO) at 3 months, symptomatic intracerebral hemorrhage (sICH), and 3-month mortality. The NLR on admission (pre-treatment) and post-treatment was collected. The PFO was defined as a modified Rankin scale (mRS) of >2.

Results

A total of 17,232 patients in 52 studies were included in the meta-analysis. The admission NLR was higher in the 3-month PFO (standardized mean difference [SMD] = 0.46, 95% confidence interval [CI] = 0.35-0.57), sICH (SMD = 0.57, 95% CI = 0.30-0.85), and mortality at 3 months (SMD = 0.60, 95% CI = 0.34-0.87). An elevated admission NLR was associated with an increased risk of 3-month PFO (odds ratio [OR] = 1.13, 95% CI = 1.09-1.17), sICH (OR = 1.11, 95% CI = 1.06-1.16), and mortality at 3 months (OR = 1.13, 95% CI = 1.07-1.20). The post-treatment NLR was significantly higher in the 3-month PFO (SMD = 0.80, 95% CI = 0.62-0.99), sICH (SMD = 1.54, 95% CI = 0.97-2.10), and mortality at 3 months (SMD = 1.00, 95% CI = 0.31-1.69). An elevated post-treatment NLR was significantly associated with an increased risk of 3-month PFO (OR = 1.25, 95% CI = 1.16-1.35), sICH (OR = 1.14, 95% CI = 1.01-1.29), and mortality at 3 months (OR = 1.28, 95% CI = 1.09-1.50).

Conclusion

The admission and post-treatment NLR can be used as cost-effective and easily available biomarkers to predict the 3-month PFO, sICH, and mortality at 3 months in patients with AIS treated with reperfusion therapy. The post-treatment NLR provides better predictive power than the admission NLR.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42022366394.

Relationship between proximity and physiological stress levels in hunter-gatherers: The Hadza

In recent years there has been a great deal of documentation on how social relationships are related to various aspects of human wellbeing. However, until recently most studies investigating the effects of social relationships on wellbeing have applied social network measures to reported social contacts. Recent advances in the application of bio-loggers in biological studies have now made it possible to quantify social relationships based on in-person, rather than self-reported, social interactions. We used GPS-derived in-camp and out-of-camp proximity data to analyse how in-person proximity is related to Hair Cortisol Concentration (HCC) among Hadza hunter-gatherers. Time spent in close proximity to other camp members was associated with higher HCC, especially in women. In contrast, individuals who spent more time in close out-of-camp proximity to their best friend experienced lower HCC. Our study suggests that physiological costs related to group living might be mitigated by in-person interactions with close friends. We also find that the location (i.e., in-camp vs out-of-camp) of proximity to others and self-perceived friends is associated with HCC among the Hadza.

Increased immunological markers in female adolescents with non-suicidal self-injury

BACKGROUND

Nonsuicidal self-injury (NSSI) is a prevalent health problem among adolescents and commonly associated with psychological stressors such as childhood maltreatment and comorbid psychiatric disorders (e.g., depression). There is evidence that alterations of immunological markers may occur in the context of both environmental stress and psychopathological development.

METHOD

Here, we investigated differences in plasma/serum leukocytes, cortisol, c-reactive protein and interleukin-6 in a large sample of female adolescents with NSSI (n = 155) and healthy controls (HC, n = 42). Further, we assessed correlations between inflammatory markers, depression severity and the severity of childhood maltreatment.

RESULTS

The absolute number of leukocytes and the leukocyte/cortisol ratio (adjusted for body mass index and smoking) were significantly higher in NSSI as compared to HC, whereas interleukin-6 and CRP levels did not differ significantly between groups. Childhood maltreatment scores were significantly correlated with the leukocyte/cortisol ratio and depression severity was significantly correlated with both, absolute leukocyte numbers and the leukocyte/cortisol ratio.

CONCLUSIONS

Our results suggest that an immune activation can be detected in female adolescents with NSSI. Depression and childhood maltreatment, which are commonly reported in NSSI, may potentially underlie immune activation and partially explain group differences.

Loneliness, Depression, and Genetics in the Elderly: Prognostic Factors of a Worse Health Condition?

Loneliness is considered a prognostic factor for poorer health status in the elderly. It is proposed to analyze the role of loneliness in health status in terms of various factors. A total of 1747 individuals from the pilot survey of the Aging in Spain Longitudinal Study (ELES-PS) were reviewed. ELES is a cross-sectional study for collecting health variables, food habits, socioeconomic data, and cognitive and functional capacities, which was carried out on a Spanish representative sample of noninstitutionalized persons of 50 years of age or older. Moreover, since telomere shortening is associated with cellular senescence, 35 telomere-related SNPs and cognitive impairments were analyzed. The results characterize the "solos" as males of 50-60 years, who were overweight and had lower levels of hemoglobin and neutrophils. There is also an association between five SNPs related to telomere length and BDNF. A group of people with loneliness and depression was identified with poorer health and cognitive status, poorer perception of their quality of life, poorer quality of sleep, and lower physical activity. Therefore, it follows that telomeres and BDNF play a role as intermediaries between loneliness and depression and their relationship with a worse state of health.

Psychosocial working conditions and chronic low-grade inflammation in geriatric care professionals: A cross-sectional study

Background

Chronic low-grade inflammation has been suggested as a key factor in the association between stress exposure and long-term health. Care work is recognized as a profession with a high degree of job stress and health risks. However, for care professionals, the study base on inflammatory activity due to adverse working conditions is limited.

Objective

The aim of this study was to explore associations between self-reported psychosocial working conditions and care professionals’ biomarkers of systemic low-grade inflammation.

Methods

N = 140 geriatric care professionals (79.3% females, mean age = 44.1 years) of six care facilities were enrolled in a cross-sectional study consisting of standardized medical examinations and employee surveys. Standardized questionnaires were used for evaluation of psychosocial work characteristics (work overload, job autonomy, social support) based on Karasek’s job strain model. Blood samples were drawn for two biomarkers of inflammatory activity: C-reactive protein (CRP) and leukocyte count. Analyses comprised uni- and multivariate logistic and linear regression analyses.

Results

We determined a proportion of 5.4% of care professionals with increased low-grade inflammation. We further observed a relationship between job autonomy and CRP, such that reports of high job autonomy were associated with increased levels of CRP (adjusted OR = 4.10, 95% CI [1.10, 15.26], p = .035), which was robust in additional analyses on further potential confounders. No significant associations with participants’ leukocyte numbers were found.

Conclusions

This exploratory study contributes to the research base on links between workplace stress and ensuing illness in care professionals. Our findings may help to identify risk and protective factors of the work environment for chronic low-grade inflammation. The results require further scrutiny, and future prospective studies on associations of psychosocial working conditions, low-grade inflammation and long-term health outcomes in care professionals are needed.

The immunomodulatory effects of social isolation in mice are linked to temperature control

Living in isolation is considered an emerging societal problem that negatively affects the physical wellbeing of its sufferers in ways that we are just starting to appreciate. This study investigates the immunomodulatory effects of social isolation in mice, utilising a two-week program of sole cage occupancy followed by the testing of immune-inflammatory resilience to bacterial sepsis. Our results revealed that mice housed in social isolation showed an increased ability to clear bacterial infection compared to control socially housed animals. These effects were associated with specific changes in whole blood gene expression profile and an increased production of classical pro-inflammatory cytokines. Interestingly, equipping socially isolated mice with artificial nests as a substitute for their natural huddling behaviour reversed the increased resistance to bacterial sepsis. Together these results suggest that the control of body temperature through social housing and huddling behaviour are important factors in the regulation of the host immune response to infection in mice and might provide another example of the many ways by which living conditions influence immunity.

Chronic stress increases transcriptomic indicators of biological aging in mouse bone marrow leukocytes

Research with animals and humans has demonstrated that chronic stress exposure can impact key biological aging pathways such as inflammation and DNA damage, suggesting a mechanism through which stress may increase risk for age-related disease. However, it is less clear whether these effects extend to other hallmarks of the aging process, such as cellular senescence. Male SCID mice were exposed to 14 days of restraint stress, with (n ​= ​6) or without (n ​= ​10) propranolol administration, or a non-stress control condition (n ​= ​10). Normal femoral bone marrow leukocytes were isolated from engrafted leukemia cells that had been injected prior to the stressor, as the mice were also under a cancer challenge. We performed whole genome transcriptional profiling to assess indicators of biological aging: cell stress, DNA damage repair, cellular senescence markers p16^INK4a and p21, and the pro-inflammatory senescence-associated secretory phenotype (SASP). ANCOVAs that adjusted for tumor load and Fisher's pairwise comparisons revealed that stressed mice had enhanced p16^INK4a (p ​= ​.02) and p21 (p ​= ​.004), lower DNA damage repair (p ​< ​.001), and higher SASP (p ​= ​.03) gene expression than control mice. Stressed mice also showed up-regulated beta-adrenergic (CREB) and inflammatory (NF-кB, AP-1) and down-regulated cell stress (Nrf2) transcription factor activity relative to control mice (ps ​< ​.01). Propranolol reversed CREB and Nrf2 activity (ps ​< ​.03). Findings suggest that chronic stress exposure can impact several key biological aging pathways within bone marrow leukocytes and these effects may be partially mediated by sympathetic beta-adrenergic receptor activation.

From work stress to disease: A computational model

In modern society, work stress is highly prevalent. Problematically, work stress can cause disease. To help understand the causal relationship between work stress and disease, we present a computational model of this relationship. That is, drawing from allostatic load theory, we captured the link between work stress and disease in a set of mathematical formulas. With simulation studies, we then examined our model’s ability to reproduce key findings from previous empirical research. Specifically, results from Study 1 suggested that our model could accurately reproduce established findings on daily fluctuations in cortisol levels (both on the group level and the individual level). Results from Study 2 suggested that our model could accurately reproduce established findings on the relationship between work stress and cardiovascular disease. Finally, results from Study 3 yielded new predictions about the relationship between workweek configurations (i.e., how working hours are distributed over days) and the subsequent development of disease. Together, our studies suggest a new, computational approach to studying the causal link between work stress and disease. We suggest that this approach is fruitful, as it aids the development of falsifiable theory, and as it opens up new ways of generating predictions about why and when work stress is (un)healthy.

Loneliness is linked to specific subregional alterations in hippocampus-default network covariation

Social interaction complexity makes humans unique. But in times of social deprivation, this strength risks exposure of important vulnerabilities. Human social neuroscience studies have placed a premium on the default network (DN). In contrast, hippocampus (HC) subfields have been intensely studied in rodents and monkeys. To bridge these two literatures, we here quantified how DN subregions systematically covary with specific HC subfields in the context of subjective social isolation (i.e., loneliness). By codecomposition using structural brain scans of ∼40,000 UK Biobank participants, loneliness was specially linked to midline subregions in the uncovered DN patterns. These association cortex patterns coincided with concomitant HC patterns implicating especially CA1 and molecular layer. These patterns also showed a strong affiliation with the fornix white matter tract and the nucleus accumbens. In addition, separable signatures of structural HC-DN covariation had distinct associations with the genetic predisposition for loneliness at the population level.

NEW & NOTEWORTHY The hippocampus and default network have been implicated in rich social interaction. Yet, these allocortical and neocortical neural systems have been interrogated in mostly separate literatures. Here, we conjointly investigate the hippocampus and default network at a subregion level, by capitalizing structural brain scans from ∼40,000 participants. We thus reveal unique insights on the nature of the “lonely brain” by estimating the regimes of covariation between the hippocampus and default network at population scale.

Glucocorticoid resistance and β2-adrenergic receptor signaling pathways promote peripheral pro-inflammatory conditions associated with chronic psychological stress: A systematic review across species

Activation of the HPA-axis and SNS are widely accepted to link chronic stress with elevated levels of peripheral pro-inflammatory markers in blood. Yet, empirical evidence showing that peripheral levels of glucocorticoids and/or catecholamines mediate this effect is equivocal. Recent attention has turned to the possibility that cellular sensitivity to these ligands may contribute to inflammatory mediators that accompany chronic stress. We review current evidence for the association of chronic stress with glucocorticoid receptor (GR) and β-adrenergic receptor (β-AR) signaling sensitivity. Across 15 mouse, 7 primate, and 19 human studies, we found that chronic stress reliably associates with downregulation in cellular GR sensitivity, alterations in intracellular β-AR signaling, and upregulation in pro-inflammatory biomarkers in peripheral blood. We also present evidence that alterations in GR and β-AR signaling may be specific to myeloid progenitor cells such that stress-related signaling promotes release of cells that are inherently less sensitive to glucocorticoids and differentially sensitive to catecholamines. Our findings have broad implications for understanding mechanisms by which chronic stress may contribute to pro-inflammatory phenotypes.

Intercellular Adhesion Molecule-1-Induced Posttraumatic Brain Injury Neuropathology in the Prefrontal Cortex and Hippocampus Leads to Sensorimotor Function Deficits and Psychological Stress

Intercellular adhesion molecule-1 (ICAM-1) promotes adhesion and transmigration of circulating leukocytes across the blood-brain barrier (BBB). Traumatic brain injury (TBI) causes transmigrated immunocompetent cells to release mediators [function-associated antigen (LFA)-1 and macrophage-1 antigen (Mac-1)] that stimulate glial and endothelial cells to express ICAM-1 and release cytokines, sustaining neuroinflammation and neurodegeneration. Although a strong correlation exists between TBI-mediated inflammation and impairment in functional outcome following brain trauma, the role of ICAM-1 in impairing functional outcome by inducing neuroinflammation and neurodegeneration after TBI remains inconclusive. The experimental TBI was induced in vivo by fluid percussion injury (FPI; 10 and 20 psi) in wild-type (WT) and ICAM-1-/- mice and in vitro by stretch injury (3 psi) in brain endothelial cells. We manipulate ICAM-1 pharmacologically and genetically and conducted several biochemical analyses to gain insight into the mechanisms underlying ICAM-1-mediated neuroinflammation and performed rotarod, grid-walk, sucrose preference, and light-dark tests to assess functional outcome. TBI-induced ICAM-1-mediated neuroinflammation and cell death occur via LFA-1 or Mac-1 signaling pathways that rely on oxidative stress, matrix metalloproteinase (MMP), and vascular endothelial growth factor (VEGF) pathways. The deletion or blocking of ICAM-1 resulted in a better outcome in attenuating neuroinflammation and cell death as marked by the markers such as NF-kB, IL-1β, TNF-α, cleaved-caspase-3 (cl-caspase-3), Annexin V, and by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and Trypan blue staining. ICAM-1 deletion in TBI improves sensorimotor, depression, and anxiety-like behavior with significant upregulation of norepinephrine (NE), dopamine (DA) D1 receptor (DAD1R), serotonin (5-HT)1AR, and neuropeptide Y (NPY). This study could establish the significance of ICAM-1 as a novel therapeutic target against the pathophysiology to establish functional recovery after TBI.

Inflammation and future depressive symptoms among recently bereaved spouses

Major depressive disorder (MDD) is an important contributor to the total disease burden because of its high comorbidity with chronic illnesses. Many people with high levels of depressive symptoms exhibit elevated systemic inflammation, but inflammation is not a necessary determinant of depression onset. Among those who recently experienced the death of a spouse, we investigated whether (a) inflammation assessed early in bereavement predicted future depressive symptoms and whether (b) inflammation predicted change in depressive symptoms from baseline to follow-up. Ninety-nine spousally bereaved individuals (M=68.61, SD=10.70) from a larger study were evaluated at baseline (3 months post-death) and follow-up (6 months post-death). Subjects received a venous blood draw and completed the Center for Epidemiologic Studies Depression Scale (CES-D). Stimulated T-cell derived cytokines (IL-6, TNF-α, and IFN-γ) were assessed individually and as a pro-inflammatory composite index. After controlling for confounding factors (i.e., age, sex, body mass index, race, ethnicity, anti-inflammatory medication, days since spousal death, smoking status, comorbidities), individuals with higher levels of IL-6, TNF-α, and IFN-γ at baseline exhibited more depressive symptoms (composite index, p = .05) and an increased probability of experiencing clinical levels of depression (CES-D score ≥16) (composite index, p = .04). Inflammatory levels were not predictive of change in depressive symptoms or in clinical depression status from baseline to follow-up. Among individuals who did not experience clinical levels of depression at baseline, baseline inflammatory levels predicted clinical levels of depression 3 months later (p = .03). This study provides support for an inflammatory mechanism underlying depression following bereavement. It suggests that one's inflammatory profile following a significant social stressor in older adulthood can be prognostic of depression risk months later. These findings add to our understanding of the physiological and mental health risks experienced by the bereaved population and provide insight into identifying vulnerable widow(er)s at risk for maladaptive grief coping.

Friends from the Future: A Scoping Review of Research into Robots and Computer Agents to Combat Loneliness in Older People

BACKGROUND AND AIM

Loneliness is a common problem in older adults and contributes to poor health. This scoping review aimed to synthesize and report evidence on the effectiveness of interventions using social robots or computer agents to reduce loneliness in older adults and to explore intervention strategies.

METHODS

The review adhered to the Arksey and O'Malley process for conducting scoping reviews. The SCOPUS, PUBMED, Web of Science, EMBASE, CINAHL, PsycINFO, ACM Digital Library and IEEE Xplore databases were searched in November, 2020. A two-step selection process identified eligible research. Information was extracted from papers and entered into an Excel coding sheet and summarised. Quality assessments were conducted using the Mixed Methods Appraisal Tool.

RESULTS

Twenty-nine studies were included, of which most were of moderate to high quality. Eighteen were observational and 11 were experimental. Twenty-four used robots, four used computer agents and one study used both. The majority of results showed that robots or computer agents positively impacted at least one loneliness outcome measure. Some unintended negative consequences on social outcomes were reported, such as sadness when the robot was removed. Overall, the interventions helped to combat loneliness by acting as a direct companion (69%), a catalyst for social interaction (41%), facilitating remote communication with others (10%) and reminding users of upcoming social engagements (3%).

CONCLUSION

Evidence to date suggests that robots can help combat loneliness in older adults, but there is insufficient research on computer agents. Common strategies for reducing loneliness include direct companionship and enabling social interactions. Future research could investigate other strategies used in human interventions (eg, addressing maladaptive social cognition and improving social skills), and the effects of design features on efficacy. It is recommended that more robust experimental and mixed methods research be conducted, using a combination of validated self-report, observational, and interview measures of loneliness.

Interplay between social isolation and loneliness and chronic systemic inflammation during the COVID-19 pandemic in Japan: Results from U-CORONA study

In the face of the global coronavirus disease 2019 (COVID-19) pandemic, billions of people were forced to stay at home due to the implementation of social distancing and lockdown policies. As a result, individuals lost their social relationships, leading to social isolation and loneliness. Both social isolation and loneliness are major risk factors for poor physical and mental health status through enhanced chronic inflammation; however, there might be an interplay between social isolation and loneliness on the association with chronic inflammation. We aimed to clarify the link between social relationships and inflammation in the context of the COVID-19 pandemic by distinguishing whether social isolation only, loneliness only, or both were associated with chronic inflammation markers among community-dwelling adults. The data of 624 people (aged 18-92 years, mean 51.4) from the Utsunomiya COVID-19 seROprevalence Neighborhood Association (U-CORONA) study, which targeted randomly sampled households in Utsunomiya city, Japan, were analyzed. Social isolation was assessed as a structural social network by asking the number of social roles they have on a daily basis. Loneliness was measured with the UCLA loneliness scale. As chronic inflammation biomarkers, neutrophil-to-lymphocyte ratio (NLR) and the concentration of high-sensitivity C-reactive protein (CRP) were measured. Generalized estimating equations method was employed to take into account the correlations within households. Isolated-Lonely condition (i.e., being both socially isolated and feeling lonely) was associated with higher NLR among men (B = 0.141, 95%CI = -0.01 to 0.29). Interestingly, Nonisolated-Lonely condition (i.e., not socially isolated but feeling lonely) was associated with lower CRP among women (B = -0.462, 95%CI = -0.82 to -0.10) and among the working-age population (B = -0.495, 95%CI = -0.76 to -0.23). In conclusion, being both socially isolated and feeling lonely was associated with chronic inflammation. Assessing both social isolation and loneliness is critical for proper interventions to mitigate the impact of poor social relationships on health, especially in the context of the COVID-19 pandemic.

Social isolation in mice: behavior, immunity, and tumor growth

The aim of this study was to investigate the behavioral, immunological, and neurological effects of long-term isolation in an animal model. Male C3H/eB mice wereraised in either social isolation or standard conditions for 6 weeks. At 10 weeks, each group was further divided into 3 sets. (A) Physical strength and behavior were evaluated with the grip strength, hot plate, staircase, and elevated plus-maze tests. Natural-killer cell activity and lymphocyte proliferation were measured. (B) Half the animals were subjected to electric shock with 3 reminders, and freezing time was evaluated at each reminder. Cortisone levels were evaluated after 16 weeks. (C)Mice were injected with 38 C-13 B lymphoma cells and followed for tumor size and survival. Strength evaluation yielded asignificantly lower body weight and grip strength in the socially isolated mice. Behavioral test results were similar in the two groups. The pattern of reactions to stress conditioning differed significantly, with the socially isolated mice showing an incline in freezing with each successive reminder, and the control mice showing a decline. The socially isolated mice had significantly attenuated tumor growth, with no significant difference in survival from control mice. There were no significant between-group differences in immunological parameters. In conclusion, social isolation serves as a model for chronic stress. It was associated with significant changes in stress conditioning reaction, resembling symptoms of post-traumatic stress disorder, and attenuated tumor development. No differences from controls were found in behavior tests, immune parameters, or survival after tumor cell inoculation.Lay summaryThis article explores biological and behavioral consequences of social isolation in a mice model. Our results show that social isolation leads to changes in the Hypothalamic-hypophyseal-adrenal axis, which in turn alter the response to stress. Additionally, social isolation was shown to impact tumor progression.

Stressed-Out Oral Immunity: A Gateway From Socioeconomic Adversity to Periodontal Disease

OBJECTIVE

It has been suggested that adverse socioeconomic conditions "get under the skin" by eliciting a stress response that can trigger periodontal inflammation. We aimed to a) estimate the extent to which socioeconomic position (SEP) is associated with periodontal disease (PD) and proinflammatory oral immunity, and b) determine the contribution of psychosocial stress and stress hormones to these relationships.

METHODS

In this cross-sectional study (n = 102), participants (20-59 years old) completed financial and perceived stress questionnaires and underwent full-mouth periodontal examinations. SEP was characterized by annual household income and educational attainment. Cortisol, a biological correlate of chronic stress, was assessed in hair samples. Oral immunity was characterized by assessing oral inflammatory load and proinflammatory oral neutrophil function. Blockwise Poisson and logistic regression models were applied.

RESULTS

Compared with lower SEP, individuals in the middle- and higher-income categories had a significantly lower probability of PD (incidence rate ratio [IRR] = 0.5 [confidence interval {CI} = 0.3-0.7] and IRR = 0.4 [95% CI = 0.2-0.7]) and oral inflammatory load (IRR = 0.6 [95% CI = 0.3-0.8] and IRR = 0.5 [95% CI = 0.3-0.7]) and were less likely to have a proinflammatory oral immune function (odds ratio [OR] = 0.1 [95% CI = 0.0-0.7] and OR = 0.1 [95% CI = 0.0-0.9]). PD and oral immune parameters were significantly associated with financial stress and cortisol. Adjusting for financial stress and cortisol partially attenuated the socioeconomic differences in PD to IRR = 0.7 (95% CI = 0.5-0.8) and IRR = 0.6 (95% CI = 0.5-0.7) for the middle- and higher-income categories, respectively. Similar results were observed for proinflammatory immunity (OR = 0.2 [95% CI = 0.0-1.8] and OR = 0.3 [95% CI = 0.0-2.3]).

CONCLUSION

These findings suggest that psychosocial stress may contribute to a proinflammatory immunity that is implicated in PD pathobiology and provide insight into social-to-biological processes in oral health.

Association of inflammatory and platelet volume markers with clinical outcome in patients with anterior circulation ischaemic stroke after endovascular thrombectomy

Background: To determine the correlation of inflammatory and platelet volume indices with the severity of stroke and 3-month clinical outcomes in patients with acute ischemic stroke (AIS) after endovascular thrombectomy (EVT).Methods: A retrospective analysis was conducted for AIS patients who underwent EVT at our hospital from 2015 to 2019. Inflammatory factors, including white blood count, neutrophil count, lymphocyte count, neutrophil to lymphocyte ratio (NLR), high-sensitivity C-reactive protein (hs-CRP), procalcitonin (PCT) and interleukin-6 (IL-6), and platelet volume indices, including platelet count (PC), mean platelet volume (MPV), platelet distribution width (PDW) and MPV/PC levels were assessed. Results were analyzed between patients with favorable and unfavorable outcomes at 3 months post-EVT.Results: A total of 257 AIS patients were included in the study. There were 86 (33.5%) patients with favorable functional outcomes at 3 months. Compared to patients with favorable outcomes, those with poor outcomes have lower lymphocyte count, higher neutrophil count and NLR levels. There were no differences in hs-CRP,PCT and IL-6 between the two groups. The correlation analysis showed that the increase in MPV, PDW, and MPV/PC was related to the high level of the NIHSS score at admission. Multivariate logistic regression analysis showed that higher NLR levels are an independent risk factor for unfavorable outcomes at 3 months (OR = 1.141; 95% CI 1.061 to 1.227, P = 0.000).Conclusions: MPV, PDW, and MPV/PC are associated with stroke severity. Higher NLR levels upon admission may predict unfavorable functional outcomes in patients with AIS after undergoing EVT.Abbreviations ACA: anterior cerebral artery; AIS: acute ischemic stroke; ASPECTS: alberta stroke program early CT score; BMI: body mass index; DBP: diastolic blood pressure; END: early neurological deterioration; EVT: endovascular thrombectomy; hs-CRP: high-sensitivity C-reactive protein; HT: hemorrhagic transformation; ICA: internal carotid artery; IL-6: interleukin-6; IS: ischemic progression; LAA: Large-Artery Atherosclerosis; MCA: middle cerebral artery; MPV: mean platelet volume; mTICI: modified thrombolysis in cerebral infarction; NIHSS: National Institute of Health stroke scale; NLR: neutrophil to lymphocyte ratio; OTP: onset-to-puncture; PC: platelet count; PCT: procalcitonin; PDW: platelet distribution width; SBP: systolic blood pressure; sICH: symptomatic intracerebral hemorrhageWBC: white blood cell.

Mindfulness-Based Stress Reduction Buffers Glucocorticoid Resistance Among Older Adults: A Randomized Controlled Trial

OBJECTIVE

Mindfulness interventions have been effective for improving a range of health outcomes; however, pathways underlying these effects remain unclear. Inflammatory processes may play a role, possibly through increased resistance of immune cells to the anti-inflammatory effects of glucocorticoids (i.e., glucocorticoid resistance, or GCR). Here, we conducted an initial examination of whether mindfulness training mitigates GCR among lonely older adults.

METHODS

Lonely older adults (65-85 years; n = 190) were randomly assigned to an 8-week Mindfulness-Based Stress Reduction (MBSR) or a matched Health Enhancement Program (HEP). Whole blood drawn before and after the intervention and at 3-month follow-up was incubated with endotoxin and varying concentrations of dexamethasone, and interleukin-6 production was assessed using enzyme-linked immunosorbent assay. GCR was assessed as the concentration of dexamethasone required to decrease the stimulated interleukin-6 response by 50% (half maximal inhibitory concentration), with higher concentrations indicating greater GCR. Mixed-effects linear models tested time (pre, post, follow-up) by condition (MBSR versus HEP) effects.

RESULTS

There was no overall time by condition effect on GCR across all time points. However, a significant time by condition effect was observed from preintervention to postintervention (d = 0.29), such that MBSR buffered increases in GCR observed in the HEP group. Although MBSR showed small, nonsignificant reductions in GCR from preintervention to 3-month follow-up, group differences were not maintained at the 3-month follow-up (d = 0.10).

CONCLUSIONS

Results suggest that MBSR may protect against declines in the sensitivity of immune cells to the anti-inflammatory effects of glucocorticoids among at-risk lonely older adults and show value in studying this biological mechanism in future trials.Trial Registration: Clinical Trials identifier NCT02888600.

The association of cortisol levels with leukocyte distribution is disrupted in the metabolic syndrome

BACKGROUND

Leukocyte glucocorticoid sensitivity (GCS) pertains to the responsivity of leukocytes to the regulating actions of glucocorticoids, such as cortisol. Impaired endocrine regulation may link the metabolic syndrome (MetS) to the development of cardiovascular disease. We tested if the physiological association between endogenous cortisol levels and peripheral leukocyte composition becomes disrupted in individuals with MetS.

METHODS

MetS was assessed among 689 German industrial employees. The covariance between cortisol levels and hematologic parameters (i.e., proportions of neutrophils and lymphocytes) and their ratio was explored, which has been proposed as a proxy for GCS in vivo. Cortisol level before blood collection was assessed by repeated saliva collection, and the area under the curve was calculated. Linear regression models were adjusted for potential confounders including age, gender, BMI, income, and lifestyle factors.

RESULTS

Cortisol levels did not differ between subgroups. Participants without MetS (n = 552) showed the expected association of cortisol with hematologic parameters (β = 0.207 to 0.216; p values < 0.001). No association (β = 0.078 to 0.083; p values > 0.10) was found among those with MetS (n = 137), consistent with a reduced GCS. Analyses of separate MetS components showed that reduced GCS was associated specifically with decreased high-density lipoprotein and elevated fasting plasma glucose.

CONCLUSIONS

Utilizing a novel statistical approach to infer GCS, this study provided first epidemiological evidence of aberrant physiological regulation of leukocyte distribution by endogenous cortisol levels among individuals with MetS. These findings underline the idea that MetS may involve disruption of endocrine-immune regulation.

Health Factors as Potential Mediators of the Longitudinal Effect of Loneliness on General Cognitive Ability

OBJECTIVE

Higher levels of loneliness in older adulthood predict cognitive decline, but research on mediating mechanisms is sparse. We examine multisystemic physiological risk, functional ability, self-rated health, depressive symptoms, and social participation as mediating processes for the association between loneliness and general cognitive ability over a 10-year follow-up in an older adult sample.

METHODS

Three waves of data from 3,005 individuals (mean intake age: 69.30 (SD: 7.85) years; female = 51.61%) recruited during Wave 1 of the National Social Life, Health, and Aging Project were used to test whether hypothesized mediators collected at the 5-year follow-up explained effects of baseline loneliness on 10-year general cognitive ability.

RESULTS

The relationship between baseline loneliness and 10-year general cognitive ability was not mediated by multisystemic physiological risk. Functional ability (b = -0.24, SE = 0.05, p <0.001), self-rated health (b = -0.08, SE = 0.02, p <0.001), depressive symptoms (b= -0.20, SE = 0.05, p <0.001), and social participation (b = -0.03, SE = 0.01, p = 0.016) significantly mediated effects. Indirect effects remained significant after adjusting for demographic covariates and 5-year general cognitive ability, except social participation.

DISCUSSION

Loneliness may influence cognitive ability indirectly, signaling waning physical and psychiatric health more proximally correlated with cognitive ability. These mechanisms may serve as targets of intervention for cognitive maintenance in lonely older adults.

Living alone and risk of dementia: A systematic review and meta-analysis

AIMS

To systematically review longitudinal studies on living alone and incident dementia, to pool the results in a meta-analysis and calculate the population risk.

METHODS

Embase, Medline and PsycInfo were searched from inception to August 2019 for longitudinal cohort studies of people living alone and risk of dementia. Relative risks (RR) were extracted and effect sizes pooled, with a sensitivity analysis for risk of bias (QUIPS quality rating tool). Population Attributable Fraction (PAF) was calculated, with prevalence of living alone calculated from UK Census data.

RESULTS

Twelve studies were identified for inclusion, nine of which had low risk of bias. The pooled effect size indicated an elevated risk of incident dementia when living alone (all studies RR = 1.30; 95 % CI: 1.15-1.46; low risk of bias studies (RR = 1.31; 95 % CI: 1.13-1.51). The PAF for living alone was 8.9 %.

CONCLUSIONS

Social isolation is a more important risk factor for dementia than previously identified, with living alone associated with greater population risk than physical inactivity, hypertension, diabetes and obesity.

Perceived efficacy of COVID-19 restrictions, reactions and their impact on mental health during the early phase of the outbreak in six countries

The COVID-19 pandemic forced millions of people to drastically change their social life habits as governments employed harsh restrictions to reduce the spread of the virus. Although beneficial to physical health, the perception of physical distancing and related restrictions could impact mental health. In a pre-registered online survey, we assessed how effective a range of restrictions were perceived, how severely they affected daily life, general distress and paranoia during the early phase of the outbreak in Brazil, Colombia, Germany, Israel, Norway and USA. Most of our over 2000 respondents rated the restrictions as effective. School closings were perceived as having the strongest effect on daily life. Participants who believed their country reacted too mildly perceived the risk of contracting SARS-CoV-2 to be higher, were more worried and expressed reduced beliefs in the ability to control the outbreak. Relatedly, dissatisfaction with governmental reactions corresponded with increased distress levels. Together, we found that satisfaction with one's governmental reactions and fear appraisal play an important role in assessing the efficacy of restrictions during the pandemic and their related psychological outcomes. These findings inform policy-makers on the psychological factors that strengthen resilience and foster the well-being of citizens in times of global crisis.

The role of oxidative stress in cardiovascular disease caused by social isolation and loneliness

Loneliness and social isolation are common sources of chronic stress in modern society. Epidemiological studies have demonstrated that loneliness and social isolation increase mortality risk as much as smoking or alcohol consumption and more than physical inactivity or obesity. Loneliness in human is associated with higher blood pressure whereas enhanced atherosclerosis is observed in animal models of social isolation. Loneliness and social isolation lead to activation of the hypothalamic-pituitary-adrenocortical (HPA) axis, enhanced sympathetic nerve activity, impaired parasympathetic function and a proinflammatory immune response. These mechanisms have been implicated in the development of cardiovascular disease conferred by social isolation although a causal relationship has not been established so far. There is evidence that oxidative stress is likely to be a key molecular mechanism linking chronic psychosocial stress to cardiovascular disease. NADPH oxidase-mediated oxidative stress in the hypothalamus has been shown to be required for social isolation-induced HPA axis activation in socially isolated rats. Oxidative stress in the rostral ventrolateral medulla is also a key regulator of sympathetic nerve activity. In the vasculature, oxidative stress increases vascular tone and promote atherogenesis through multiple mechanisms. Thus, preventing oxidative stress may represent a therapeutic strategy to reduce the detrimental effects of social stress on health.

Glucocorticoids prime the inflammatory response of human hippocampal cells through up-regulation of inflammatory pathways

Increased pro-inflammatory cytokines and an overactive hypothalamic-pituitary-adrenal (HPA) axis have both been implicated in the pathogenesis of depression. However, these explanations appear contradictory because glucocorticoids are well recognised for their anti-inflammatory effects. Two hypotheses exist to resolve this paradox: the mediating presence of glucocorticoid receptor resistance, or the possibility that glucocorticoids can potentiate inflammatory processes in some circumstances. We sought to investigate these hypotheses in a cell model with significant relevance to depression: human hippocampal progenitor cells. We demonstrated that dexamethasone in vitro given for 24 hours and followed by a 24 hours rest interval before an immune challenge potentiates inflammatory effects in these neural cells, that is, increases the IL-6 protein secretion induced by stimulation with IL-1β (10 ng/mL for 24 hours) by + 49% (P < 0.05) at a concentration of 100 nM and by + 70% (P < 0.01) for 1 μM. These effects are time- and dose-dependent and require activation of the glucocorticoid receptor. Gene expression microarray assays using Human Gene 2.1st Array Strips demonstrated that glucocorticoid treatment up-regulated several innate immune genes, including chemokines and Nod-like receptor, NLRP6; using transcription factor binding motifs we found limited evidence that glucocorticoid resistance was induced in the cells. Our data suggests a mechanism by which stress may prime the immune system for increased inflammation and suggests that stress and inflammation may be synergistic in the pathogenesis of depression.

Social regulation of inflammation related gene expression in the multi-ethnic study of atherosclerosis

BACKGROUND

Exposure to adverse social factors has been associated with an altered inflammatory profile, a risk factor for several acute and chronic diseases. Differential gene expression may be a biological mediator in the relationship. In this study, associations between a range of social factors and expression of inflammation-related genes were investigated.

METHODS

Social factor and gene expression data were collected from 1,264 individuals in the Multi-Ethnic Study of Atherosclerosis (MESA). Inflammation-related genes were identified from the Gene Ontology database. The associations between social factors and gene expression were first assessed using the Global Analysis of Covariance (Global ANCOVA) gene set enrichment test. When the global test was significant, linear regression and elastic net penalized regression were employed to identify the individual gene transcripts within each gene set associated with the social factor.

RESULTS

Loneliness (p = 0.003), chronic burden (p = 0.002), and major or lifetime discrimination (p = 0.045) were significantly associated with global expression of the chronic inflammatory gene set. Of the 20 transcripts that comprise this gene set, elastic net selected 12 transcripts for loneliness, 8 for chronic burden, and 3 for major or lifetime discrimination. Major or lifetime discrimination was also associated with the inflammatory response (p = 0.029), regulation of the inflammatory response (p = 0.041), and immune response (p = 0.025) gene sets in global analyses, and 53, 136, and 26 transcripts were selected via elastic net for these gene sets respectively. There were no significant associations in linear regression analyses after adjustment for multiple testing.

CONCLUSIONS

This study highlights gene expression as a biological mechanism through which social factors may affect inflammation.

Effect of mobile phone radiation on oxidative stress, inflammatory response, and contextual fear memory in Wistar rat

In the present lifestyle, we are continuously exposed to radiofrequency electromagnetic field (RF-EMF) radiation generated mainly by mobile phones (MP). Among other organs, our brain and hippocampus in specific, is the region where effect of any environmental perturbation is most pronounced. So, this study was aimed to examine changes in major parameters (oxidative stress, level of pro-inflammatory cytokines (PICs), hypothalamic-pituitary-adrenal (HPA) axis hormones, and contextual fear conditioning) which are linked to hippocampus directly or indirectly, upon exposure to mobile phone radiofrequency electromagnetic field (MP-RF-EMF) radiation. Exposure was performed on young adult male Wistar rats for 16 weeks continuously (2 h/day) with MP-RF-EMF radiation having frequency, power density, and specific absorption rate (SAR) of 1966.1 MHz, 4.0 mW/cm², and 0.36 W/kg, respectively. Another set of animals kept in similar conditions without any radiation exposure serves as control. Towards the end of exposure period, animals were tested for fear memory and then euthanized to measure hippocampal oxidative stress, level of circulatory PICs, and stress hormones. We observed significant increase in hippocampal oxidative stress (p < 0.05) and elevated level of circulatory PICs viz. IL-1beta (p < 0.01), IL-6 (p < 0.05), and TNF-alpha (p < 0.001) in experimental animals upon exposure to MP-RF-EMF radiation. Adrenal gland weight (p < 0.001) and level of stress hormones viz. adrenocorticotropic hormone (ACTH) (p < 0.01) and corticosterone (CORT) (p < 0.05) were also found to increase significantly in MP-RF-EMF radiation-exposed animals as compared with control. However, alteration in contextual fear memory was not significant enough. In conclusion, current study shows that chronic exposure to MP-RF-EMF radiation emitted from mobile phones may induce oxidative stress, inflammatory response, and HPA axis deregulation. However, changes in hippocampal functionality depend on the complex interplay of several opposing factors that got affected upon MP-RF-EMF exposure.

Loneliness and psychotic experiences in a general population sample

Increased loneliness has been associated with common mental disorders including psychotic disorders. However, as yet, little information is available on the association between loneliness and the occurrence of psychotic experiences (PEs), especially when adjusted for confounding factors. To address this deficit, the current study examined the relationship between PEs and loneliness in a general population sample in the United States (N = 974). We fitted three regression models to examine the associations between loneliness and PEs, using hierarchical adjustments for sociodemographic factors, adverse childhood experiences, and common mental disorders. Even at the highest level of adjustment, loneliness was significantly associated with increased odds for any PEs (OR = 1.25, 95% CI = 1.13-1.39). The same applied to the association between loneliness and delusional mood (OR = 1.29, 95% CI = 1.15-1.44). For delusion of reference and persecution, delusions of control, and hallucinations, there were no significant associations when adjusted for sociodemographic factors, adverse childhood experiences, and common mental disorders. These results suggest that increased loneliness is associated with PEs, particularly delusional mood. Future studies should employ longitudinal data and biological measures to examine potential causal relationships and underlying mechanisms.

Perceived social isolation and cognitive functioning. Longitudinal findings based on the German Ageing Survey

OBJECTIVES

There is a lack of longitudinal studies, which are both based on nationally representative samples and use standardized instruments to quantify social isolation. Thus, the purpose of this study was to determine the link between perceived social isolation and cognitive functioning longitudinally.

METHODS/DESIGN

Longitudinal data with n = 6420 from 2014 (wave 5) to 2017 (wave 6) were drawn from the German Ageing Survey (nationally representative sample of individuals aged 40 years and over). Perceived social isolation was assessed using a scale by Bude and Lantermann. Cognitive functioning was quantified using the established digit symbol test. To reduce the problem of unobserved heterogeneity, linear fixed effects regressions were used.

RESULTS

Regressions showed that increases in perceived social isolation were associated with decreases in cognitive functioning. With regard to covariates, decreases in cognitive functioning were associated with increases in aging and worsening self-rated health, whereas changes in marital status, employment status, income, physical functioning, and physical illnesses were not associated with the outcome measure.

CONCLUSIONS

Based on a nationally representative sample and exploiting the panel data structure, the study findings extend current knowledge by showing that increasing perceived social isolation contributes to decreases in cognitive functioning among individuals aged 40 years and over longitudinally. Future longitudinal studies based on panel data methods are required to validate the study findings.

Social Support and Subclinical Coronary Artery Disease in Middle-Aged Men and Women: Findings from the Pilot of Swedish CArdioPulmonary bioImage Study

Social support has been associated with coronary artery disease (CAD), particularly in individuals who have sustained a cardiovascular event. This study investigated the relationship between social support and subclinical CAD among 1067 healthy middle-aged men and women. Social support was assessed with validated social integration and emotional attachment measures. Subclinical CAD was assessed as a coronary artery calcium score (CACS) using computed tomography. There was no association between social support and CACS in men. In women, low social support was strongly linked to cardiovascular risk factors, high levels of inflammatory markers, and CACS > 0. In a logistic regression model, after adjustment for 12 cardiovascular risk factors, the odds ratio (95% confidence intervals) for CACS > 0 in women with the lowest social integration, emotional attachment, and social support groups (reference: highest corresponding group) were 2.47 (1.23-5.12), 1.87 (0.93-3.59), and 4.28 (1.52-12.28), respectively. Using a machine learning approach (random forest), social integration was the fourth (out of 12) most important risk factor for CACS > 0 in women. Women with lower compared to higher or moderate social integration levels were about 14 years older in "vascular age". This study showed an association between lack of social support and subclinical CAD in middle-aged women, but not in men. Lack of social support may affect the atherosclerotic process and identify individuals vulnerable to CAD events.

Social engagement and loneliness are differentially associated with neuro-immune markers in older age: Time-varying associations from the English Longitudinal Study of Ageing

OBJECTIVES

This study aimed to explore time-varying associations between social engagement, living status and loneliness and neuro-immune markers in older adults, and ascertain whether results are explained by socioeconomic position, health behaviours or depression.

METHODS

We analysed blood samples from 8780 adults aged 50 and above from the English Longitudinal Study of Ageing across three waves of data collection: 2004/5, 2008/9 and 2012/2013. We used fixed effects modelling to estimate the relationship between loneliness, social isolation, living alone and levels of fibrinogen, insulin like growth factor-1 (IGF-1), white blood cell (WBC) count and C-reactive protein (CRP), whilst accounting for all time-invariant and identified time-varying confounders.

RESULTS

Higher levels of social engagement and living with somebody were associated with lower levels of CRP, fibrinogen and WBC, while lower levels of loneliness were associated with higher levels of IGF-1. These associations were found to be independent of time-invariant factors such as gender, medical history, previous patterns of social behaviours, unobserved aspects of social class, and genetics, and time-varying factors such as income, physical health, health behaviours, and depression.

CONCLUSIONS

Aspects of social engagement were associated with lower levels of inflammation whilst loneliness was inversely related to the regulation of inflammation. This suggests there could be different biological pathways involved in objective and subjective aspects of social connections.

The Biology of Social Adversity Applied to Oral Health

Biological embodiment is a concept derived from Engel's biopsychosocial model to health, theorized as the process by which adverse social exposures trigger neuroendocrine and immune responses, leading to disease and/or increased disease susceptibility. This critical review discusses the biopsychosocial model as applied to oral health and its relevance to oral health policy while deciphering some of the pathobiological processes underlying social adversity. In periodontal disease, for example, such processes can occur via the activation of the hypothalamic-pituitary-adrenal axis and the consequent release of the chronic stress hormone cortisol. The latter contributes to a proinflammatory immune state that increases the risk for periodontal inflammation. Recent research shows that cortisol relates to an elevated oral inflammatory load, demonstrated as hyperactive neutrophils that are pivotal to periodontal tissue damage. Consistent with the biopsychosocial model, this relationship is amplified in those of lower income and higher financial stress. Similarly, among children from lower socioeconomic backgrounds, cortisol is linked to a higher cariogenic bacterial load. Such findings implicate the stress pathway as key in the oral pathogenic process, particularly under social/socioeconomic adversity. Collectively, this work emphasizes the importance of addressing social factors in alleviating oral disease burden and reducing the social gaps therein.

Social isolation as a promising animal model of PTSD comorbid suicide: neurosteroids and cannabinoids as possible treatment options

Post-traumatic stress disorder (PTSD) is a psychiatric condition characterized by drastic alterations in mood, emotions, social abilities and cognition. Notably, one aspect of PTSD, particularly in veterans, is its comorbidity with suicide. Elevated aggressiveness predicts high-risk to suicide in humans and despite the difficulty in reproducing a complex human suicidal behavior in rodents, aggressive behavior is a well reproducible behavioral trait of suicide. PTSD animal models are based on a peculiar phenotype, including exaggerated fear memory and impaired fear extinction associated with neurochemical dysregulations in the brain circuitry regulating emotion. The endocannabinoid and the neurosteroid systems regulate emotions and stress responses, and recent evidence shows these two systems are interrelated and critically compromised in neuropsychiatric disorders. For instance, levels of the neurosteroid, allopregnanolone, as well as those of the endocannabinoids, anandamide and its congener, palmitoylethanolamide are decreased in PTSD. Similarly, the endocannabinoid system and neurosteroid biosynthesis are altered in suicidal individuals. Selective serotonin reuptake inhibitors (SSRIs), the only FDA-approved treatments for PTSD, fail to help half of the treatment-seeking patients. This highlights the need for developing biomarker-based efficient therapies. One promising alternative to SSRIs points to stimulation of allopregnanolone biosynthesis as a treatment and a valid end-point to predict treatment response in PTSD patients. This review highlights running findings on the role of the endocannabinoid and neurosteroid systems in PTSD and suicidal behavior both in a preclinical and clinical perspective. A specific focus is given to predictive PTSD/suicide animal models. Ultimately, we discuss the idea that disruption of neurosteroid and endocannabinoid biosynthesis may offer a novel promising biomarker axis to develop new treatments for PTSD and, perhaps, suicidal behavior.

Loneliness and biological responses to acute stress in people with Type 2 diabetes

Loneliness is linked with all-cause mortality and coronary heart disease. Altered neuroendocrine and inflammatory responses to stress constitute potential pathways linking loneliness and ill-health. Stress responsivity is modified in people with Type 2 diabetes, but it is unclear whether loneliness influences biological stress responses in this population. We assessed interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1RA), monocyte chemoattractant protein-1 (MCP-1), and cortisol responses to acute stress in 135 people with Type 2 diabetes. Loneliness was measured used the Revised UCLA Loneliness Scale. Loneliness was inversely associated with cortisol output poststress (B = -4.429, p = 0.019) independent of age, sex, education, marital status, body mass index, and smoking. Lonelier individuals had raised MCP-1 concentrations 75 min poststress independent of covariates (B = 0.713, p = 0.022). No associations between loneliness and IL-6 or IL-1RA concentrations were detected. These results suggest that loneliness is associated with disturbances in stress responsivity in people with diabetes, and the impact of loneliness on health in people with diabetes may be mediated in part through dysregulation of inflammatory and neuroendocrine systems. Future research is required to understand if such changes increase the risk of poorer outcomes in this population.

Microglial Phagocytosis of Neurons: Diminishing Neuronal Loss in Traumatic, Infectious, Inflammatory, and Autoimmune CNS Disorders

Errors in neuron-microglial interaction are known to lead to microglial phagocytosis of live neurons and excessive neuronal loss, potentially yielding poorer clinical outcomes. Factors that affect neuron-microglial interaction have the potential to influence the error rate. Clinical comorbidities that unfavorably impact neuron-microglial interaction may promote a higher rate of neuronal loss, to the detriment of patient outcome. This paper proposes that many common, clinically modifiable comorbidities have a common thread, in that they all influence neuron-microglial interactions. Comorbidities like traumatic brain injury, infection, stress, neuroinflammation, loss of neuronal metabolic integrity, poor growth factor status, and other factors, all have the potential to alter communication between neurons and microglia. When this occurs, microglial phagocytosis of live neurons can increase. In addition, microglia can shift into a morphological form in which they express major histocompatibility complex II (MHC-II), allowing them to function as antigen presenting cells that present neuronal debris as antigen to invading T cells. This can increase risk for the development of CNS autoimmunity, or can exacerbate existing CNS autoimmunity. The detrimental influence of these comorbidities has the potential to contribute to the mosaic of factors that determine patient outcome in some CNS pathologies that have neuropsychiatric involvement, including TBI and CNS disorders with autoimmune components, where excessive neuronal loss can yield poorer clinical outcomes. Recognition of the impact of these comorbidities may contribute to an understanding of the common clinical observation that many seemingly disparate factors contribute to the overall picture of case management and clinical outcome in these complex disorders. In a clinical setting, knowing how these comorbidities can influence neuron-microglial interaction can help focus surveillance and care on a broader group of potential therapeutic targets. Accordingly, an interest in the mechanisms underlying the influence of these factors on neuron-microglial interactions is appropriate. Neuron-microglial interaction is reviewed, and the various mechanisms by which these potential comorbidities influence neuro-microglial interaction are described.

Racial discrimination and leukocyte glucocorticoid sensitivity: Implications for birth timing

RATIONALE

Psychological stress-induced cortisol elevations appear to contribute to preterm birth. Yet, some studies suggest that the biological ramifications of racial discrimination-associated stress are unique and may involve development of decreased glucocorticoid sensitivity despite normalized cortisol levels.

OBJECTIVE

In this study, we examined the effects of racial discrimination on maternal cortisol output, leukocyte glucocorticoid sensitivity, and the degree of correspondence between cortisol levels and birth timing in an African American cohort.

METHOD

A generally healthy prospective cohort was enrolled at 28-32 weeks gestation (n = 91). The Experiences of Discrimination scale was administered, whole blood collected, and plasma cortisol levels, cytokine levels, and leukocyte counts quantified for examination of patterns of endogenous feedback.

RESULTS

Racial discrimination in the mid-tertile was associated with greater maternal cortisol levels than the bottom tertile among women reporting internalizing responses (b* = 0.68, p = 0.001). Decreased leukocyte glucocorticoid sensitivity was witnessed at greater frequencies of experiences of racial discrimination, as evidenced by decreased correspondence between maternal cortisol levels and plasma IL-8 levels, monocyte counts, and lymphocyte counts (p values ≤ 0.043). The association between maternal cortisol levels and birth timing differed by discrimination tertile (p values ≤ 0.005), with greater cortisol levels predictive of earlier birth among women without (b* = -0.59, p < 0.001) but not with racial discrimination (ps ≥ 0.497).

CONCLUSION

We provide novel evidence of decreased glucocorticoid sensitivity at increasing frequency of exposure to racial discrimination. Our findings suggest that the biology of preterm birth may depend upon racial discriminatory exposures, favoring pathways dependent upon glucocorticoid-induced increases in leukocyte tissue surveillance versus glucocorticoid resistance-associated inflammatory aberrations at increasing levels of exposure. Precision approaches to prenatal care are sorely needed to combat preterm birth, particularly among African American women, with efforts dependent upon further research examining the pathways contributing to the syndrome dependent upon the totality of an individual's exposures.

Stressful life events predict one-year change of leukocyte composition in peripheral blood

A plethora of cross-sectional studies suggest that psychological stress resulting from experiencing stressful life events (SLE) can result in an altered immune response. Potential maladaptive immune changes may outlast the event and affect the organism long after stress cessation. As a consequence, an increased vulnerability for immune-mediated pathologies (e.g. arthritis, diabetes) may develop over the life span. The objective of the present study was to monitor the longitudinal kinetics of peripheral white blood cells (WBCs; neutrophils, lymphocytes, and monocytes) in response to SLE. Here we present blood, hair, and behavioural measures obtained in the Dresden Burnout Study, at first visit (T1; N = 446) and one year later (T2; N = 173). Cumulative impact of SLE was assessed at T1 with the Life Stressor Checklist (LSC-R). Results indicate a significant increase in neutrophils (+2.8% per each 10 LSC-R points) between T1 and T2 in association with reported SLE. The change in neutrophils tended to correlate with the change in hair cortisol (Coheńs f = 0.6). We propose that SLE trigger immunological alterations that persist across time and thereby promote a continuous effect on WBC distribution. Such an effect might advance subclinical inflammatory processes, reduce an individualś immune defence, and promote a link between psychological stress and physical disease.