Inflammatory parameters in sexually abused children

Interpersonal violence exposure and inflammation during adolescence and young adulthood

Exposure to violence increases young peoples' risk of developing mental and physical health problems. Chronic stress-related upregulation of innate immune system activity and the development of low-grade inflammation may partially underlie this health risk. However, much of the previous research has been limited to cross-sectional studies utilizing between-person analytic designs, susceptible to confounding by unmeasured factors. In this six-wave panel study of N=157 female adolescents and young adults, we tested within-person associations between interpersonal violence exposure and multiple measures of inflammatory activity. Ex vivo culture studies suggested that participants' immune cells were more reactive to microbial stimulation and less sensitive to inhibition by glucocorticoids after violence. Numbers of circulating monocyte cells increased after violence, but serum levels of interleukin-6 and c-reactive protein did not. Findings from this within-person analysis suggest that violence exposure up-regulates innate immune system activity during adolescence and young adulthood in ways that may increase mental and physical health risk.

The association between victimization and inflammation: A meta-analysis

BACKGROUND

To meta-analyze the existing studies examining the association of childhood and adulthood victimization with inflammation and to explore the moderating variables that affect these relationships.

METHODS

Relevant work published before 28th February 2021 was identified by searching five major databases. We analyzed the cross-sectional data extracted from cross-sectional and longitudinal studies using the random-effects model to estimate the correlation (r) as the pooled effect size and further conducted subgroup analyses and sensitivity analyses.

RESULTS

A total of 37 articles finally met the inclusion criteria, including studies for C-reactive protein (CRP) (k = 23; N_CRP = 11,780), interleukin-6 (IL-6) (k = 31; N_IL-6 = 8943), and tumor necrosis factor-alpha (TNF-α) (k = 14; N_TNF-α = 4125). Overall, victimization has a significantly positive association with inflammation, with a small effect size (r = 0.122). Specifically, effect sizes were the largest for TNF-a (r = 0.152), followed by IL-6 (r = 0.119), and CRP (r = 0.084). Additionally, the effect sizes for victimization against children were r = 0.145 (k = 6) for childhood victimization - childhood inflammation, and r = 0.139 (k = 27) for childhood victimization - adulthood inflammation, which appear to be larger than that of victimization against adults (r = 0.039; k = 2).

LIMITATIONS

Only a small number of studies on adult victimization were included. In addition, we only analyzed the cross-sectional relationship and did not have sufficient data to compare different types of victimization and single vs. multiple victimizations.

CONCLUSIONS

Victimization is associated with a heightened inflammatory response. As victimization against children may have a stronger effect than victimization against adults, prevention of victimization targeting the childhood period may be necessary. Studies with more robust methodologies (i.e., representative, longitudinal, and multi-country designs) are needed to confirm these findings and to unpack the underlying mechanisms.

Adverse Childhood Events and Health Biomarkers: A Systematic Review

Background: This systematic review aimed to summarize evidence reporting epigenetic and/or neuro-immuno-endocrine embedding of adverse childhood events (ACEs) in children, with a particular focus on the short-term biological effect of those experiences.

Methods: A search was conducted in PsycINFO®, PubMed®, Isi Web of Knowledge and Scopus, until July 2019, to identify papers reporting the short-term biological effects of exposure to ACEs.

Results: The search identified 58 studies, that were included in the review. Regarding exposure, the type of ACE more frequently reported was sexual abuse (n = 26), followed by life stressors (n = 20) and physical abuse (n = 19). The majority (n = 17) of studies showed a positive association between ACEs and biomarkers of the immune system. Regarding DNA methylation 18 studies showed more methylation in participants exposed to ACEs. Two studies presented the effect of ACEs on telomere length and showed that exposure was associated with shorter telomere length.

Conclusion: Overall the associations observed across studies followed the hypothesis that ACEs are associated with biological risk already at early ages. This is supporting evidence that ACEs appear to get “under the skin” and induce physiological changes and these alterations might be strongly associated with later development of disease.

Challenges in researching the immune pathways between early life adversity and psychopathology

Exposure to childhood adversity is a critical risk factor for the development of psychopathology. A growing field of research examines how exposure to childhood adversity is translated into biological risk for psychopathology through alterations in immune system functioning, most notably heightened levels of inflammation biomarkers. Though our knowledge about how childhood adversity can instantiate biological risk for psychopathology is growing, there remain many challenges and gaps in the field to understand how inflammation from childhood adversity contributes to psychopathology. This paper reviews research on the inflammatory outcomes arising from childhood adversity and presents four major challenges that future research must address: (a) the measurement of childhood adversity, (b) the measurement of inflammation, (c) the identification of mediators between childhood adversity and inflammation, and (d) the identification of moderators of inflammatory outcomes following childhood adversity. We discuss synergies and inconsistencies in the literature to summarize the current understanding of the association between childhood adversity, a proinflammatory phenotype, and the biological risk for psychopathology. We discuss the clinical implications of the inflammatory links between childhood adversity and psychopathology, including possibilities for intervention. Finally, this review conclude by delineates future directions for research, including issues of how best to detect, prevent, and understand these “hidden wounds” of childhood adversity.

Early life adversity exposure and circulating markers of inflammation in children and adolescents: A systematic review and meta-analysis

This study provides a comprehensive review of the published research on the association between early life adversity and markers of inflammation in children and adolescents. We conducted a systematic review of the published literature on the association between early life adversity and markers of inflammation in pediatric populations. To date, 27 studies have been published in this area representing a wide range of global populations and diverse methods of which nearly half were prospective, longitudinal studies. Of these 27, only 12 studies shared an inflammatory outcome with 4 or more other studies; 9 for CRP, and 6 for IL-6. The association between early life adversity and both CRP, z = .07 [.04, .10], and IL-6, z = .17 [-.07, .42], were small and only significant for CRP although comparable in magnitude to the effects observed in adult samples. Descriptively, the association between early life adversity and CRP appeared to be stronger in studies conducted in infants and adolescents compared with middle childhood. There was minimal evidence of publication bias for studies measuring CRP, but evidence of publication bias for studies using IL-6. Eight studies have looked at the association between early life adversity and stimulated inflammatory cytokines in vitro, and both the methods and results of these studies were mixed; the majority observed exaggerated production of inflammatory cytokines despite mixed methodological approaches that make comparisons across studies difficult. In summary, the evidence supporting an association between early life adversity and inflammation in pediatric samples is limited so far by the number of studies and their heterogeneous methodological approaches. More research that is grounded in a developmental framework and informed by the complexity of the innate immune system is needed in this area.