Interferon-γ moderation of poor sleep maintenance and depressed mood in community-dwelling older adults

Retrospective Case Study on the Evaluation of Inflammatory Markers, Macrophage Inhibitory Protein-1α and Interferon-γ in Sleep Deprivation Condition

Background and Aim

Sleep is an important physiological process that is necessary for the normal functioning of the body. Sleep greatly affects all aspects of our body, including the immune pathways or immune response system of our body, which plays a determinant role in the development and progression of chronic inflammatory diseases. In this study, we worked to find the relation between sleep deprivation and levels of pro-inflammatory markers macrophage inflammatory protein 1-alpha (MIP-1α) and interferon gamma (IFN-γ). To find the relation between sleep deprivation and levels of pro-inflammatory markers MIP-1α and IFN-γ.

Objective

To find the relation between sleep deprivation and levels of pro-inflammatory markers MIP-1α and IFN-γ.

Materials and Methods

The study was conducted with 40 individuals as participants, of which 20 were sleep-deprived (SD), and 20 had adequate amounts of sleep. The sleep duration details of the individuals were obtained by questionnaire. Blood was withdrawn from all the subjects after due consent from them. Plasma was separated and was used to evaluate their MIP-1α levels and IFN-γ levels.

Results

The MIP-1α levels and levels of IFN-γ were found to be significantly elevated in the SD individuals than that of individuals who had adequate sleep.

Conclusion

Sleep loss and sleep deprivation are associated with altered expressions of key regulatory factors and upregulation of pro-inflammatory cytokines production. Thus, sleep deprivation can be considered to be one of the major contributors to the development and progression of various chronic inflammatory diseases.

IL-6 predicts non-suicidal self-injury over 3 months in high-risk adolescents

BACKGROUND

Suicide is the second leading cause of death in 12- to 17-year-old adolescents in the USA. Research on biological mechanisms contributing to self-harm risk that could be targeted in treatment could help to prevent suicide and self-harm episodes.

AIMS

We aimed to evaluate whether markers of inflammation, interleukin-6 (IL-6) and C-reactive protein (CRP), predict self-harm over 3 months within a sample selected for elevated suicide/self-harm risk at project entry.

METHOD

Fifty-one adolescents aged 12-19 years selected for elevated suicide/self-harm risk completed three clinical interviews about suicide attempts and non-suicidal self-injury, 3 months apart. At baseline and 3 months, youth also provided blood samples, from which we assayed levels of IL-6 and CRP.

RESULTS

Using generalised mixed models, we found that greater levels of IL-6 predicted more self-harm episodes (odds ratio [OR] = 3.3, 95% CI: 1.1, 10.0) and specifically, non-suicidal self-injury (OR = 3.5, 95% CI: 1.1, 11.2), over 3 months.

CONCLUSIONS

The study findings increase our understanding of whether and how inflammation may be implicated in risk of self-harm. IL-6 may be a viable biological marker of short-term risk for self-harm.

Inflammatory hypotheses of sleep disturbance - depression link: Update and research agenda

Studies in human and experimental animal models support a role of inflammation in the aetiology of depression, yet the precise role played by sleep disturbance (i.e., difficulties falling or maintaining sleep) is poorly understood. Consistent evidence from prospective epidemiological studies suggests sleep disturbance as a predictor of major depression episodes and depression recurrence. In parallel, up to 20% of individuals with sleep disturbance have low-grade peripheral inflammation (i.e., CRP>3 mg/l), and preliminary longitudinal evidence showed that sleep disturbance may even predict the levels of inflammation. Therefore, it is possible that sleep disturbance may increase inflammation, which in turn may contribute (i.e., mediate) to the onset - or worsening - of depression. Alternatively, sleep disturbance may serve as a vulnerability factor and increase the risk of developing depressive symptoms when facing an immune challenge. The aim of this review was to summarise the state of the science on the role of sleep disturbance in contributing to depression-related inflammation. A research agenda is also proposed to advance the study of sleep disturbance in the psychoneuroimmunology of depression.

Sleep disturbance, neuro-immune markers, and depressive symptoms in older age: Conditional process analysis from the English Longitudinal Study of Aging (ELSA)

This study aimed to investigate the long-term association between subjective sleep disturbance and depressive symptoms in older adults, and ascertain whether this association is partially mediated by neuro-immune markers, while testing the moderation of sex using conditional process analyses, i.e., combinations of mediation and moderation analyses. We analysed data of 2124 participants aged 50 and above from the English Longitudinal Study of Ageing (ELSA) across three waves of data collection. Sleep disturbance was assessed in 2008/9, serum levels of high sensitivity C-reactive protein (hs-CRP), insulin like growth factor-1 (IGF-1), white blood cell (WBC) count in 2012/2013, and self-reported depressive symptoms in 2016/2017. After accounting for health-related and psychosocial confounders, results showed that sleep disturbance significantly predicted depressive symptoms at follow-up in the whole sample and hs-CRP in women, but not in men. Hs-CRP also predicted depressive symptoms only in women. Moreover, hs-CRP significantly mediated the association between sleep disturbance and depressive symptoms in women, but not in men. The association between sleep disturbance and IFG-1was marginal, and the latter did not mediate the association between sleep and depressive symptoms neither in women nor in men. Results on WBC count were all non-significant. In conclusion, sleep disturbance resulted significantly associated with depressive symptoms in a long-term follow-up. Moreover, ELSA data provide preliminary evidence that increased inflammation may mediate this association in women. Future longitudinal studies may advance the knowledge in the field considering the mediating role of proinflammatory cytokines such as interleukin-6.