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

Identification of Inflammatory Mediators in Saliva Samples From Hospitalized Newborns: Potential Biomarkers?

Saliva measurements serve as a noninvasive tool for clinically monitoring newborns (NB) and children, a vulnerable population with promising potential for both research and clinical practice. Saliva acts as a repository for various inflammatory biomarkers involved in diverse biological functions. Particularly for children, it offers numerous advantages when compared to plasma and urine sampling. Nevertheless, there is a significant knowledge gap regarding detectable levels of cytokines in the saliva of newborns and children, as well as studies aiming to assess the relationship of this content with physiological and pathological processes.

OBJECTIVES

To characterize the levels of 11 inflammatory mediators (IFNg, IL1b, IL2, IL4, IL6, IL8, IL10, IL12, IL17, TNF, and VEGF) in saliva samples from NB on the first and second day of hospitalization in the Neonatal Intensive Care Unit (NICU).

METHOD

Exploratory study, descriptive, nested within a primary clinical, observational, and prospective study, conducted in the NICU of a public hospital in São Paulo, Brazil. Demographic data and vital signs were recorded in the clinical records of 90 NB, and five saliva samples from 5 NB were collected between the first and second day of life (D1-D2) at approximately 8-hr intervals (8-9 am, 4-5 pm, and 11-12 pm). Saliva samples were used for the measurement of 11 cytokines (IFNg, IL1b, IL2, IL4, IL6, IL8, IL10, IL12, IL17, TNF, and VEGF).

RESULTS

Five NBs participated in this exploratory study, and the vital signs showed variability from the first (D1) to the second day (D2) of hospitalization, variability similar to that of the total population of the primary study. The presence and levels of the 11 cytokines were detected in the saliva samples, as well as a statistical correlation between 10 cytokines (IFNg, IL1b, IL2, IL4, IL6, IL10, IL12, IL17, TNF, and VEGF) and vital signs.

CONCLUSIONS

The novelty of measuring inflammatory mediators in saliva samples from hospitalized NBs in the NICU is highlighted, providing support and new perspectives for the development of clinical and experimental research and an opportunity for developing and implementing new salivary biomarkers in different population segments.

Associations between chronic stress and hair cortisol in children: A systematic review and meta-analysis

OBJECTIVES

This review systematically examined the associations between chronic stress and hair cortisol concentration (HCC) in children, and the potential modification effects of type, measurement period and scales of chronic stress, child age and sex, hair length and HCC measurement method, characteristics of study site, and congruence between time periods measured for chronic stress and HCC.

METHODS

Pubmed, Wed of Science, and APA PsycINFO were systematically searched for articles examining the association between chronic stress and HCC.

RESULTS

Thirteen studies from five countries with 1,455 participants were included in the systematic review and nine studies were included in the meta-analysis. Meta-analysis revealed that chronic stress was associated with HCC (pooled-r = 0.09, 95 % CI: 0.03, 0.16). Stratified analyses revealed that type, measurement time and scales of chronic stress, hair length and measurement method of HCC, and the congruence between time periods measured for chronic stress and HCC modified such correlations. The positive correlations between chronic stress and HCC were significant for studies measuring chronic stress as stressful life events, assessing chronic stress within the past six months, extracting HCC from 1 cm, 3 cm, or 6 cm of hair, measuring HCC by LC-MS/MS, or having congruence between time periods measured for chronic stress and HCC. The potential modifying effects of sex and country developmental status could not be concluded due to the limited number of studies included.

CONCLUSIONS

Chronic stress was positively correlated with HCC, varying by characteristics and measurements of chronic stress and HCC. HCC could be a biomarker for chronic stress among children.

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.

Salivary Biomarker Profiles and Chronic Fatigue among Nurses Working Rotation Shifts: An Exploratory Pilot Study

Although nurses’ fatigue affects their well-being and patient safety, no effective objective measurements exist. We explored the profiles of salivary biomarkers associated with nurses’ chronic fatigue across several shifts. This longitudinal study involved 45 shiftwork nurses and collected their saliva samples before two night and two day shifts for a month. Chronic fatigue was measured using the Cumulative Fatigue Symptom Index before the first night shift. Biomarker profiles were analyzed using hierarchical cluster analysis, and chronic fatigue levels were compared between the profiles. Cortisol profiles were classified into high- and low-level groups across two day shifts; the low-level group presented significantly higher irritability and unwillingness to work. Secretory immunoglobulin A (s-IgA) profiles across the four shifts were classified into high- and low-level groups; the high-level group had significantly higher depressive feelings, decreased vitality, irritability, and unwillingness to work. Cortisol (two day shifts) and s-IgA (four shifts) profiles were combined, and (i) cortisol low-level and s-IgA high-level and (ii) cortisol high-level and s-IgA low-level groups were identified. The former group had significantly higher chronic fatigue sign and irritability than the latter group. The profiles of salivary cortisol and s-IgA across several shifts were associated with nurses’ chronic fatigue.