Increased levels of inflammation among infants with disorganized histories of attachment

Lingering Effects of Early Institutional Rearing and Cytomegalovirus Infection on the Natural Killer Cell Repertoire of Adopted Adolescents

Adversity during infancy can affect neurobehavioral development and perturb the maturation of physiological systems. Dysregulated immune and inflammatory responses contribute to many of the later effects on health. Whether normalization can occur following a transition to more nurturing, benevolent conditions is unclear. To assess the potential for recovery, blood samples were obtained from 45 adolescents adopted by supportive families after impoverished infancies in institutional settings (post-institutionalized, PI). Their immune profiles were compared to 39 age-matched controls raised by their biological parents (non-adopted, NA). Leukocytes were immunophenotyped, and this analysis focuses on natural killer (NK) cell populations in circulation. Cytomegalovirus (CMV) seropositivity was evaluated to determine if early infection contributed to the impact of an atypical rearing. Associations with tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), two cytokines released by activated NK cells, were examined. Compared to the NA controls, PI adolescents had a lower percent of CD56bright NK cells in circulation, higher TNF-α levels, and were more likely to be infected with CMV. PI adolescents who were latent carriers of CMV expressed NKG2C and CD57 surface markers on more NK cells, including CD56dim lineages. The NK cell repertoire revealed lingering immune effects of early rearing while still maintaining an overall integrity and resilience.

Participation in an Attachment-Based Home Visiting Program Is Associated with Lower Child Salivary C-Reactive Protein Levels at Follow-Up

OBJECTIVE

Exposure to early childhood adversity is associated with an increased risk for physiological disruption, including increased inflammation. Early interventions that support the mother-child relationship have been shown to potentially buffer negative psychosocial outcomes related to early adversity, but it is unclear whether these interventions have long-term biological effects. We evaluated whether prior participation in Minding the Baby® (MTB), an attachment-based home visiting intervention for young mother-infant dyads living in underserved communities, is associated with lower child salivary inflammatory biomarkers compared with controls at follow-up.

METHODS

Ninety-seven maternal-child dyads (n = 43 intervention and n = 54 controls) enrolled in a follow-up study of the MTB randomized controlled trial, an average of 4.6 years after RCT completion. Children provided salivary specimens. We used adjusted linear regression to examine the relationship between MTB participation and child salivary inflammatory biomarkers (C-reactive protein [CRP], interleukin [IL]-1β, IL-6, IL-8, and TNF-α).

RESULTS

Children were on average 6.6 years old, 48% female, and identified as non-Hispanic/Latino Black/African American (34%) and Hispanic/Latino (63%). Participation in MTB was associated with lower salivary CRP levels (β = -0.31, SE = 0.28, p = 0.003) compared with controls. Participation in MTB was not associated with salivary cytokine levels.

DISCUSSION

Participation in an intensive two-generation home visiting intervention such as MTB may reduce salivary inflammatory biomarkers associated with early childhood adversity. Replication and further research are needed to improve the understanding of the potential for early childhood interventions to buffer the biological embedding of early adversity.

Associations of peripheral blood DNA methylation and estimated monocyte proportion differences during infancy with toddler attachment style

Attachment is a motivational system promoting felt security to a caregiver resulting in a persistent internal working model of interpersonal behavior. Attachment styles are developed in early social environments and predict future health and development outcomes with potential biological signatures, such as epigenetic modifications like DNA methylation (DNAm). Thus, we hypothesized infant DNAm would associate with toddler attachment styles. An epigenome-wide association study (EWAS) of blood DNAm from 3-month-old infants was regressed onto children's attachment style from the Strange Situation Procedure at 22-months at multiple DNAm Cytosine-phosphate-Guanine (CpG) sites. The 26 identified CpGs associated with proinflammatory immune phenotypes and cognitive development. In post-hoc analyses, only maternal cognitive-growth fostering, encouraging intellectual exploration, contributed. For disorganized children, DNAm-derived cell-type proportions estimated higher monocytes -cells in immune responses hypothesized to increase with early adversity. Collectively, these findings suggested the potential biological embedding of both adverse and advantageous social environments as early as 3-months-old.

Assessment of Unresolved/Disorganized State of Mind in Relation to Attachment: A ROC Curve Study Using the Adult Attachment Interview and the Measure of Parental Style

OBJECTIVE

The main objective of the present study was to use the Receiver Operating Characteristic (ROC) curve analysis to identify cut-off points for a self-report measure assessing parental style, i.e., the Measure of Parental Style (MOPS), that are able to discriminate individuals with disorganized internal working models (IWMs) of attachment with adequate accuracy, in terms of sensitivity and specificity. Establishing cut-off points for the MOPS could provide clinicians and researchers with a valuable tool to investigate the role of disorganized IWMs as a link between parental styles and mental health.

METHOD

A sample of 90 university students (mean age = 21.21 ± 2.05, females = 66) was enrolled in the study. We used the Adult Attachment Interview (AAI) to assess disorganized IWM and the MOPS to assess parental styles. Subsequently, we used ROC curve analysis to pursue the objective of the study.

RESULTS

The ROC curve analysis showed that the MOPS total score (i.e., the combination of maternal and paternal dimensions) was able to discriminate individuals with disorganized IWMs from individuals with organized IWMs (AUC= 0.77). Specifically, a score ≥ 25 (Youden index= 0.497) categorized individuals with a sensitivity of 0.69 (69% of participants with disorganized IWMs were correctly identified) and a specificity of 0.81 (19% of participants were incorrectly identified as having disorganized IWMs).

CONCLUSIONS

Although the AAI has demonstrated high psychometric properties for assessing attachment representations in adulthood, its use is difficult when studies with large samples are to be conducted. As an alternative to the AAI, the MOPS can be used in studies with large populations, but no cut-off has yet been proposed. Here, we have identified cut-off points for the MOPS that are capable of detecting disorganized IWMs of attachment with adequate accuracy, and we suggest that this self-report is a useful brief instrument for detecting disorganized IWMs when time constraints prevent the use of the AAI (e.g., in studies with large samples or epidemiological studies).

Immunological and other biological correlates of the impact of antenatal depression on the mother-infant relationship

Antenatal depression affects up to 20% of pregnancies, yet research has historically focused on postnatal depression and its effects on mothers and their offspring. Studies are now emerging highlighting the impact that depression in pregnancy can also carry on both members of the dyad, including difficulties with psychological, physical, and social functioning. More specifically, researchers have begun to examine whether antenatal depression may lead to difficulties in the developing mother-infant relationship and subsequent infant attachment. While much of the research on this has explored psychosocial mechanisms behind the pathway from antenatal depression to a disrupted relationship in the postpartum, few studies have looked at biological underpinnings of this process. Of the literature that exists, it has been found that mothers with depression in pregnancy have lower levels of oxytocin and increased levels of inflammatory markers, plausibly creating difficulties in the mother-infant bonding process, leading to impaired mother-infant interactions and non-secure infant attachment. Furthermore, infants with non-secure attachments are at risk of entering a proinflammatory state due to a dysregulated stress response system. Overall, the literature on the neurobiology of mother-infant interactions and infant attachment in the context of antenatal depression is sparse, thus warranting future research.

Annual Research Review: Social relationships and the immune system during development

A child's social relationships serve critical functions during development. The interface between a child's social world and their immune system, particularly innate immunity, which helped children survive in the face of infections, nutritional scarcity, and violence throughout human history, is the focus of this Annual Research Review. This article reviews the state of research on social relationships and innate immune inflammation during childhood. Warmth and rejection in childhood social relationships, as well as physical trauma and unpredictable social environments, were not consistently related to circulating inflammatory markers such as interleukin-6 and C-reactive protein during childhood. Instead, links between social environments and inflammation were observed in studies that focus on children with greater background risk factors, such as low family socioeconomic status, family history of mood disorders, or presence of chronic interpersonal stressors combined with acute episodic stressors. In addition, studies on worse childhood social environments and greater inflammation in adulthood were more consistent. Warmth and rejection in the social environment may be related to sensitivity of immune cells to the anti-inflammatory actions of glucocorticoids, though this is primarily observed in adolescent women at risk for depression. Additional mechanistic evidence suggests that greater warmth and less rejection are related to processes that regulate inflammation, including greater expression of the glucocorticoid receptor gene and lower expression of genes that are responsive to the pro-inflammatory transcription factor NF-kappa B. The article concludes by discussing implications of the interface between a child's social relationships and inflammation for mental health and other recent (on evolutionary timescales) health threats, as well as recommendations for future research, and recommendations for researchers interested in integrating inflammatory measures in developmental research.

Beyond Early Adversity: The Role of Parenting in Infant Physical Health

OBJECTIVE

Although ample evidence indicates that child health is compromised by early adversity (e.g., abuse and poverty), less is known about the contribution of parenting in low-stress contexts to child health, especially in infancy. This longitudinal study extends previous research on early adversity to ask the question: Does quality of parental care predict infant health in a low-risk community sample?

METHOD

Participants were 187 healthy mothers and their full-term infants (86 girls) from the Netherlands, followed from birth to age 1. Home observations of mothers' behavior were conducted during a naturalistic task (bathing session) when infants were 5 weeks old. Trained researchers interviewed mothers about the infants' health and prescribed antibiotic use every month for 12 months. Infant health problems were categorized into 4 domains according to the International Classification of Primary Care to capture a range of outcomes: respiratory, digestive, skin, and general illnesses and symptoms.

RESULTS

Controlling for health-related covariates (e.g., maternal smoking and breastfeeding), maternal sensitivity predicted reduced rates of infant respiratory symptoms and skin conditions and marginally lower prescribed antibiotic use over the first year. Maternal behavior was unrelated to infant digestive and general illnesses.

CONCLUSION

Even in the absence of adversity, quality of maternal care may have implications for the development of physical health, beginning as early as the first year of life. That such findings emerge in a low-risk sample helps rule out potential confounders and underscores the importance of parenting for physical and psychological health outcomes.

Pathways to inflammation in adolescence through early adversity, childhood depressive symptoms, and body mass index: A prospective longitudinal study of Chilean infants

Early adversity, depression, and obesity are associated with increases in low-grade inflammation. However, there are few prospective and longitudinal studies to elucidate how these associations unfold in children. The present study used latent growth curve models to examine pathways between family adversity in infancy, depressive symptoms in childhood, body mass index (BMI) in childhood, and inflammation in adolescence (age = 16-18). The study is an adolescent follow-up of infants from working-class communities around Santiago, Chile, who participated in a preventive trial of iron supplementation at 6 months of age. Anthropometrics, stressful life events, maternal depression, socioeconomic status, and developmental assessments were measured at 12 months, 5 years, 10 years, and adolescence. In adolescence, participants provided blood samples for high-sensitivity C-reactive protein (hsCRP) assessment. Greater exposure to early adversity in the form of interpersonal conflict stress in infancy indirectly associated with increased hsCRP through its association to increased intercept and slope of childhood BMI. Depressive symptoms at any time were not directly or indirectly associated with increased hsCRP. These findings contribute to our understanding of how early family adversity and its associations with obesity and depressive symptoms across childhood are linked to low-grade, chronic inflammation in adolescence. The model identified as best capturing the data supported the pivotal role of childhood BMI in explaining how early-life adversity is associated with inflammation in adolescence.

Maternal stress and social support prospectively predict infant inflammation

Maternal stress has been suggested to be a risk factor for offspring health, while social support has been shown to be a protective factor for offspring functioning. Currently, research has yet to investigate how both of these factors may relate to infant inflammatory processes and associated biological aging in the first years of life. In 48 mother-infant dyads, we investigated whether maternal parenting stress and social support when infants were 12 and 18 months of age were cross-sectionally associated with infant salivary C-reactive protein (sCRP) during these times. In addition, we investigated whether parenting stress and social support were prospectively associated with later sCRP and changes in sCRP from 12 to 18 months of age, as well as whether those changes in sCRP were associated with subsequent infant salivary telomere length (sTL), a marker of biological aging. Analyses revealed that while there were no cross-sectional associations between maternal factors and infant sCRP, maternal parenting stress and social support when infants were 12 months of age predicted infant sCRP at 18 months of age. Further, maternal social support predicted changes in infant sCRP from 12 to 18 months of age. We observed a null association between infant sCRP and sTL. Implications for the ways that maternal mental health and social support may impact biological mechanisms related to disease processes in infants are discussed.

The relationship between attachment and somatoform symptoms in children and adolescents: A systematic review and meta-analysis

OBJECTIVE

Problems in childhood and adolescence are often present with recurring physical signs of illness, called somatoform symptoms. These symptoms are a common reason for consultation at both paediatric care and psychotherapeutic/psychiatric praxis. We propose that attachment is a possible predictive factor. This article provides a systematic overview of the existing research literature concerning the relationship between attachment and somatoform symptoms in children and adolescents.

METHODS

A systematic search for empirical articles from 1990 up to August 2018 focusing on this association was conducted. Out of six databases, 4994 studies were detected by using defined keywords. One study was added identified by checking reference lists. Finally, 15 studies were selected, which were the bases for the narrative review. Ten studies were included in meta-analysis.

RESULTS

Combining study results, we found that attachment cannot solely predict somatoform symptoms. Mixed results are shown. The quantitative analysis substantiated these narrative results, revealing a small but significant combined effect size of Δ ≈ .12 (95% CI .04 - .19).

CONCLUSIONS

The findings suggest that a relationship exists, but further investigations need to demonstrate that these are not only superficial. There are many developmental factors that affect the relationship between attachment and somatoform symptoms in children and adolescents. Further research should explore this interplay in order to gain a holistic and comprehensive understanding of the underlying mechanisms that lead to these correlations and to discover possible predicting factors.

Minimally-invasive methods for examining biological changes in response to chronic stress: A scoping review

BACKGROUND

Nurse researchers are increasingly interested in incorporating biological indicators related to chronic stress, or repeated or constant exposure to psychological stressors. Minimally invasive collection methods may improve access to vulnerable populations.

OBJECTIVE

To map biological indicators measured through minimally invasive methods investigating biological changes in response to chronic stress.

DESIGN, DATA SOURCES, AND METHODS

The paper seeks to answer two questions: What are the characteristics of the minimally-invasive methods used to measure the biological correlates of chronic stress? What are the limitations regarding the use of the minimally-invasive methods and/or biological indicators identified above? Authors completed a scoping review following guidelines from the Joanna Briggs Institute Manual and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Scoping Reviews. A literature search was completed in PubMed, PsycINFO, and Scopus. 2518 articles were screened and 145 studies were included. Data were extracted using a standardized extraction tool, compiled, and coded.

RESULTS

Studies included minimally-invasive methods to measure the hypothalamic-adrenal-pituitary axis (N = 173), immune and inflammatory markers (N = 118), and adult neurogenesis (N = 6). Cortisol was most frequently measured (N = 136), usually in saliva (N = 86). Studies included a variety of limitations for the methods and indicators, including concerns about timing and accuracy of collection, frequency of sampling, and controlling for acute stressors.

CONCLUSIONS

Nurse researchers have access to many minimally-invasive methods to measure altered biological processes related to chronic stress. A gap identified by this review is the paucity of minimally-invasive methods for investigating neurogenesis; the measurement of brain derived neurotrophic factor in plasma is a distal proxy and further research is needed to test the response of peripheral levels to psychosocial stress interventions. Additionally, while this scoping review allows nurse researchers to consider possible biological indicators to include in their research, future research is still needed on some of the basic premises of stress research, including agreement on the conceptualization of chronic stress.

Longitudinal associations between attachment quality in infancy, C-reactive protein in early childhood, and BMI in middle childhood: preliminary evidence from a CPS-referred sample

In the current pilot study, we examined whether insecure or disorganized attachment was associated with elevated inflammation (i.e. C-reactive protein [CRP]) in children with histories of child protective services (CPS) involvement, and whether early childhood CRP predicted body mass index (BMI) in middle childhood. Participants included 45 CPS-referred children and 39 low-risk comparison children, for whom we assessed levels of CRP in early childhood (Mean age = 4.9 years). For the CPS-referred children, who were drawn from an ongoing longitudinal study, we had attachment classifications (assessed during infancy with the Strange Situation) and BMI data (assessed during early and middle childhood); these data were not available for the low-risk comparison group. CPS-referred children who had insecure or disorganized attachments during infancy had higher levels of CRP in early childhood than CPS-referred children who had secure attachments, who had similar levels of CRP to low-risk comparison children. Among CPS-referred children, early childhood CRP predicted age 8 BMI, controlling for BMI at age 4. Findings offer preliminary support for the association between attachment quality and inflammation in early childhood, which may have implications for later physical health.

Neuroendocrine and immune pathways from pre- and perinatal stress to substance abuse

Early life adversity is a documented risk factor for substance abuse and addiction. The pre- and perinatal period (i.e., from implantation, through pregnancy, to 6 months of age) is a critical period marked by high biological plasticity and vulnerability, making perinatal stress a particularly robust form of adversity. The neuroendocrine and immune systems are key mechanisms implicated in the transmission of addiction risk. We review animal and human studies that provide preliminary evidence for links between perinatal stress, neuroendocrine and immune dysregulation, and risk for substance abuse and addiction. A translational neuroscience perspective is employed to elucidate pre- and perinatally-induced biological mechanisms linked to addiction and discuss implications for prevention and intervention efforts. Significant evidence supports associations between pre- and perinatal stress and dysregulation of the hypothalamic-pituitary-adrenal axis and immune systems as well as links between neuroendocrine/immune functioning and addiction risk. More work is needed to explicitly examine the interplay between pre- and perinatal stress and neuroendocrine/immune disruptions that together heighten substance abuse risk. Future work is needed to fully understand how pre- and perinatal stress induces biological alterations to predispose individuals to higher risk for addiction. Such knowledge will strengthen theoretically-driven and empirically-supported prevention efforts for substance abuse and addiction.

The development of attachment: Integrating genes, brain, behavior, and environment

In humans, as in other animal species, early caregiver-infant interactions influence physiological and psychological processes by modulating brain sensitivity. Furthermore, early social interaction between caregiver and infant influences infants' cognitive and socioemotional development, and subsequently the development of social, familial, and romantic relationships later in life. Here, we have collected longitudinal and cross-sectional empirical studies as well as review and perspective articles that focus on human or non-human mammals with the aim to investigate how genetic, hormonal, behavioural, and environmental factors, as well as cultural contexts, regulate early interactional experiences, and how these experiences translate into social and non-social competences later in life (see Graphical Abstract).