Comparative efficacy of psychological interventions on immune biomarkers: A systematic review and network meta-analysis (NMA)

Inflammatory biomarkers and psychological variables to assess quality of life in patients with inflammatory bowel disease: a cross-sectional study

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic gastrointestinal condition. While inflammatory biomarkers are valuable for diagnosing and monitoring the disease, their correlation with patients' quality of life (QoL) is not well-established.

PURPOSE

This study aims to investigate the correlations between inflammatory biomarkers and the quality of life (QoL) variables of individuals diagnosed with IBD in clinical remission.

METHODS

The sample of this cross-sectional study included 74 patients (80% women; 45 ± 11 years old) diagnosed with IBD. Outcome variables included faecal calprotectin (FC), C-reactive protein (CRP), cortisol levels from hair samples, and anxiety and depression assessed using the Hospital Anxiety and Depression Scale (HADS-A and HADS-D, respectively), alongside QoL evaluated with the Inflammatory Bowel Disease Questionnaire 32 (IBDQ-32). Bivariate correlations were calculated using the Pearson correlation coefficient, and stepwise linear regression analyses were conducted to identify independent factors contributing to IBDQ-32 scores.

RESULTS

The IBDQ-32 did not significantly correlate with any biomarkers. However, it exhibited a large and statistically significant negative correlation with HADS-A (r = -0.651) and HADS-D (r = -0.611) scores (p < 0.001). Stepwise linear regression analyses indicated that HADS-A was a significant and independent predictor for IBDQ-32 scores (Adjusted R2 = 0.41, β = -0.65, p < 0.001).

CONCLUSIONS

Inflammatory markers such as CRP, FC, or cortisol in hair do not play a decisive role in assessing the QoL of IBD patients. These findings emphasize the significance of considering psychological factors in evaluating and managing QoL in IBD patients in order to identify severity, suggesting that instruments like HADS should be integral to comprehensive patient assessments.

Inflammation as a mediator between adverse childhood experiences and adult depression: A meta-analytic structural equation model

Exposure to adverse childhood experiences (ACEs) confers a higher risk of developing depression in adulthood, yet the mediation of inflammation remains under debate. To test this model, we conducted a systematic review and two-stage structural equation modelling meta-analysis of studies reporting correlations between ACEs before age 18, inflammatory markers and depression severity in adulthood. Scopus, Pubmed, Medline, PsycInfo, and CINAHL were searched up to 2 October 2023. Twenty-two studies reporting data on C-reactive protein (CRP, n = 12,935), interleukin-6 (IL-6, n = 4108), tumour necrosis factor-α (TNF-α, n = 2256) and composite measures of inflammation (n = 1674) were included. Unadjusted models revealed that CRP (β = 0.003, 95 % LBCI 0.0002 to 0.0068), IL-6 (β = 0.003, 95 % LBCI 0.001 to 0.006), and composite inflammation (β = 0.009, 95 % LBCI 0.004 to 0.018) significantly mediated the association between ACEs and adult depression. The mediation effects no longer survived after adjusting for BMI; however, a serial mediation model revealed that BMI and IL-6 sequentially mediated the association between ACEs and depression (β = 0.002, 95 % LBCI 0.0005 to 0.0046), accounting for 14.59 % and 9.94 % of the variance of IL-6 and depressive symptoms, respectively. Due to the cross-sectional nature of assessment of inflammation and depression findings should be approached with caution; however, results suggest that complex interactions of psychoneuroimmunological and metabolic factors underlie the association between ACEs and adulthood depression.

Neurobiology and systems biology of stress resilience

Stress resilience is the phenomenon that some people maintain their mental health despite exposure to adversity or show only temporary impairments followed by quick recovery. Resilience research attempts to unravel the factors and mechanisms that make resilience possible and to harness its insights for the development of preventative interventions in individuals at risk for acquiring stress-related dysfunctions. Biological resilience research has been lagging behind the psychological and social sciences but has seen a massive surge in recent years. At the same time, progress in this field has been hampered by methodological challenges related to finding suitable operationalizations and study designs, replicating findings, and modeling resilience in animals. We embed a review of behavioral, neuroimaging, neurobiological, and systems biological findings in adults in a critical methods discussion. We find preliminary evidence that hippocampus-based pattern separation and prefrontal-based cognitive control functions protect against the development of pathological fears in the aftermath of singular, event-type stressors [as found in fear-related disorders, including simpler forms of posttraumatic stress disorder (PTSD)] by facilitating the perception of safety. Reward system-based pursuit and savoring of positive reinforcers appear to protect against the development of more generalized dysfunctions of the anxious-depressive spectrum resulting from more severe or longer-lasting stressors (as in depression, generalized or comorbid anxiety, or severe PTSD). Links between preserved functioning of these neural systems under stress and neuroplasticity, immunoregulation, gut microbiome composition, and integrity of the gut barrier and the blood-brain barrier are beginning to emerge. On this basis, avenues for biological interventions are pointed out.

Inflammation as an aetiological trigger for depressive symptoms in a prospective cohort of patients with inflammatory bowel disease

OBJECTIVE

Inflammatory bowel disease (IBD) is often comorbid with mood disorders and depressive symptoms. The aetiology of depressive symptoms in IBD, however, remains largely unknown. Consistent with the inflammatory hypothesis of depression, the aim of this study was to explore the prospective associations between inflammatory biomarkers and depressive symptoms in a cohort of IBD patients with and without a previous clinical diagnosis of mood disorder.

METHOD

IBD clinical activity was determined using the Harvey-Bradshaw Index for CD and the Partial Mayo score for UC; serum C-reactive protein (CRP) and faecal calprotectin (fCAL) were used as biomarkers of systemic and intestinal inflammation, respectively. Participants were administered the Hospital Anxiety and Depression Scale-depression (HADS-D) at baseline and 1-year follow-up.

RESULTS

Eighty-four participants (50 ± 16 years; 75% UC and 25% CD) were included in the main analyses. Longitudinal moderated regression models showed that baseline CRP significantly predicted follow-up HADS-D scores among individuals with a previous mood disorder diagnosis (β = 0.843, p < .001), but not among individuals without (β = -0.013, p = .896), after controlling for baseline HADS-D scores, body mass index, IBD phenotype, sex, and perceived stress. Likely due to lower power, results on FCAL (n = 31) were not statistically significant.

CONCLUSION

This study suggests that IBD patients with previous diagnosis of mood disorder may be at higher risk of inflammation-related depressive symptoms.

Do interventions for mood improve inflammatory biomarkers in inflammatory bowel disease?: a systematic review and meta-analysis

BACKGROUND

Psychoneuroimmunological mechanisms and the gut-brain axis appear relevant to disease activity and progression in Inflammatory Bowel Disease (IBD). A recent review showed no effect of psychological therapies on self-reported disease activity in IBD. This meta-analysis aims to establish whether interventions targeting mood outcomes (e.g., depression, anxiety and stress) impact inflammation levels in IBD and possible moderators of these effects.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. We searched five electronic databases and included randomised controlled trials where interventions targeted mood and assessed inflammatory outcomes pre- and post-intervention in adults with IBD. Independent reviewers screened studies, extracted data, and assessed methodological quality. Data were pooled to estimate standardised mean differences (SMDs) with 95% Confidence Intervals (CIs). A random-effects robust variance estimation accounted for studies measuring multiple biomarkers. Intervention type, mood as a primary or secondary outcome, effect on mood outcomes and IBD subtype were investigated as treatment effect moderators. Where there were sufficient biomarkers, individual meta-analyses were run (Pre-registration PROSPERO: CRD42023389401).

FINDINGS

28 RCTs involving 1789 participants met inclusion criteria. Interventions demonstrated small, statistically significant effects on biomarkers (-0.35, 95% CI: -0.48, -0.22, p < 0.001) and medium effects on mood outcomes (-0.50, 95% CI: -0.73, -0.27, p < 0.001), without evidence of substantive heterogeneity or publication bias. Individual analyses showed small effects for improved faecal calprotectin (-0.19, 95% CI: -0.34, -0.03, p = 0.018) and C-Reactive Protein (-0.29, 95% CI: -0.47, -0.10, p = 0.002). Effect sizes were larger for psychological therapy interventions (compared with exercise or antidepressants) and when there was an effect (SMD ≥0.2) on mood.

INTERPRETATION

Treatments which address mood outcomes have beneficial effects on generic inflammation as well as disease-specific biomarkers (faecal calprotectin and C-Reactive Protein). Psychological interventions and interventions with larger treatment effects on mood accentuated the effect on biomarkers. More research is required to understand the biological or behavioural mechanisms underlying this effect.

FUNDING

The Medical Research Council and the National Institute for Health and Care Research (NIHR) Maudsley Biomedical Research Centre.

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.