Only vulnerable adults show change in chronic low-grade inflammation after contemplative mental training: evidence from a randomized clinical trial

Mapping pathways to neuronal atrophy in healthy, mid-aged adults: From chronic stress to systemic inflammation to neurodegeneration?

Growing evidence implicates systemic inflammation in the loss of structural brain integrity in natural ageing and disorder development. Chronic stress and glucocorticoid exposure can potentiate inflammatory processes and may also be linked to neuronal atrophy, particularly in the hippocampus and the human neocortex. To improve understanding of emerging maladaptive interactions between stress and inflammation, this study examined evidence for glucocorticoid- and inflammation-mediated neurodegeneration in healthy mid-aged adults. N = 169 healthy adults (mean age = 39.4, 64.5% female) were sampled from the general population in the context of the ReSource Project. Stress, inflammation and neuronal atrophy were quantified using physiological indices of chronic stress (hair cortisol (HCC) and cortisone (HEC) concentration), systemic inflammation (interleukin-6 (IL-6), high-sensitive C-reactive protein (hs-CRP)), the systemic inflammation index (SII), hippocampal volume (HCV) and cortical thickness (CT) in regions of interest. Structural equation models were used to examine evidence for pathways from stress and inflammation to neuronal atrophy. Model fit indices indicated good representation of stress, inflammation, and neurological data through the constructed models (CT model: robust RMSEA = 0.041, robust χ2 = 910.90; HCV model: robust RMSEA <0.001, robust χ2 = 40.95). Among inflammatory indices, only the SII was positively associated with hair cortisol as one indicator of chronic stress (β = 0.18, p < 0.05). Direct and indirect pathways from chronic stress and systemic inflammation to cortical thickness or hippocampal volume were non-significant. In exploratory analysis, the SII was inversely related to mean cortical thickness. Our results emphasize the importance of considering the multidimensionality of systemic inflammation and chronic stress, with various indicators that may represent different aspects of the systemic reaction. We conclude that inflammation and glucocorticoid-mediated neurodegeneration indicated by IL-6 and hs-CRP and HCC and HEC may only emerge during advanced ageing and disorder processes, still the SII could be a promising candidate for detecting associations between inflammation and neurodegeneration in younger and healthy samples. Future work should examine these pathways in prospective longitudinal designs, for which the present investigation serves as a baseline.

Mindfulness-Based Stress Reduction Reduces Proinflammatory Gene Regulation But Not Systemic Inflammation Among Older Adults: A Randomized Controlled Trial

OBJECTIVE

Aging is associated with increased proinflammatory gene expression and systemic inflammation, and psychosocial stress may accelerate these changes. Mindfulness interventions show promise for reducing psychosocial stress and extending healthspan. Inflammatory pathways may play a role. In a sample of lonely older adults, we tested whether mindfulness training reduces proinflammatory gene expression and protein markers of systemic inflammation.

METHODS

Lonely older adults (65-85 years; N = 190) were randomly assigned to an 8-week Mindfulness-Based Stress Reduction (MBSR) or matched Health Enhancement Program (HEP). Blood was drawn before and after the intervention and at 3-month follow-up. In peripheral blood mononuclear cells, RNA profiling was used to assess transcriptional regulation by proinflammatory nuclear factor κB (NF-κB) as well as β-adrenergic cAMP response element-binding protein (CREB), antiviral interferon regulatory factor (IRF), and glucocorticoid receptor (GR) transcription factors. Plasma was assayed for proinflammatory markers interleukin 6 (IL-6) and C-reactive protein (CRP). Analyses tested time (pre, post, follow-up) by condition (MBSR versus HEP) effects.

RESULTS

MBSR reduced NF-κB ( d = 0.17, p = .028) but did not alter CREB ( d = 0.10, p = .20), IRF ( d = 0.13, p = .086), or GR activity ( d = 0.14, p = .063) relative to HEP over time. Contrary to predictions, there were no time by condition effects of MBSR compared with HEP on reducing circulating IL-6 or CRP.

CONCLUSIONS

In lonely older adults, MBSR reduced cellular proinflammatory gene regulation in ways that would predict reduced disease risk. However, no similar effect was observed for circulating protein markers of inflammation. These results provide specificity about how mindfulness interventions may impact distinct inflammatory markers among aging adults in ways that may have important implications for healthspan.

TRIAL REGISTRATION

Clinical Trials identifier NCT02888600.

Only Small Effects of Mindfulness-Based Interventions on Biomarker Levels of Inflammation and Stress: A Preregistered Systematic Review and Two Three-Level Meta-Analyses

Mindfulness-based interventions (MBIs) have a positive effect on biomarkers of inflammation and stress in patients with psychiatric disorders and physical illnesses. Regarding subclinical populations, results are less clear. The present meta-analysis addressed the effects of MBIs on biomarkers in psychiatric populations and among healthy, stressed, and at-risk populations. All available biomarker data were investigated with a comprehensive approach, using two three-level meta-analyses. Pre-post changes in biomarker levels within treatment groups (k = 40 studies, total N = 1441) and treatment effects compared to control group effects, using only RCT data (k = 32, total N = 2880), were of similar magnitude, Hedges g = -0.15 (95% CI = [-0.23, -0.06], p < 0.001) and g = -0.11 (95% CI = [-0.23, 0.001], p = 0.053). Effects increased in magnitude when including available follow-up data but did not differ between type of sample, MBI, biomarker, and control group or duration of the MBI. This suggests that MBIs may ameliorate biomarker levels in both psychiatric and subclinical populations to a small extent. However, low study quality and evidence of publication bias may have impacted on the results. More large and preregistered studies are still needed in this field of research.

Revisiting the stress recovery hypothesis: Differential associations of cortisol stress reactivity and recovery after acute psychosocial stress with markers of long-term stress and health

Exposure to excessive and long-term stress may result in dysregulation of the stress system, including the acute stress response. In particular, failure to downregulate stress-related reactivity may lead to prolonged stress responses and the accumulation of allostatic load. However, the contribution of altered acute cortisol recovery to chronic stress and associated health impairments has often been neglected. Addressing this lack of research, we explored whether recovery from - more so than reactivity to - acute stress captures the basal stress load of an individual. Using Piecewise Growth Curve Models with Landmark Registration, we analyzed cortisol reactivity and recovery slopes of 130 healthy participants exposed to a standardized psychosocial laboratory stressor. Reactivity and recovery were predicted by measures indicative of long-term stress and its downstream effects, including self-report questionnaires, diurnal cortisol indices [cortisol awakening response (CAR); diurnal cortisol slope], markers of pro-inflammatory activity (interleukin-6; high-sensitive C-reactive protein), and hippocampal volume (HCV). Among these measures, only an increased CAR was specifically and consistently associated with relatively impaired recovery. Since the CAR represents the physiological enhancement needed to meet the anticipated demands of the forthcoming day, this finding may highlight the contribution of cognitive processes in determining both CAR and acute stress recovery. Furthermore, greater cortisol reactivity covaried with smaller HCV, showing that increased acute reactivity translates to health-relevant downstream effects. The lack of further associations between long-term and acute stress measures may arise from biases in self-reported chronic stress and the rigorously health-screened study sample. Overall, our findings suggest that while cortisol stress recovery might not supersede reactivity as an indicator of the long-term stress load or associated health effects, recovery and reactivity have differential utility in describing individuals' allostatic states.

Utilization of Mind–Body Intervention for Integrative Health Care of COVID-19 Patients and Survivors

Recent findings suggest a correlation between COVID-19 and diabetes, although the underlying causes are still little understood. COVID-19 infection tends to induce severe symptoms in patients with underlying diabetes, increasing their mortality rate. Moreover, COVID-19 itself appears to be a diabetogenic factor. In addition, mental health conditions, such as depression due to lockdown and anxiety about infection, were found to affect glycemic control and immunity, highlighting the importance of mental health care during the pandemic. Mind–Body Intervention (MBI), which includes meditation, yoga, and qigong, has emerged as a tool for mental health management due to its effects on stress reduction and the promotion of mental and physical well-being. Here, we review the latest randomized controlled trials to determine the effects of MBI on glycemic control and the immune system and discuss the underlying mechanisms by which MBI facilitates the virtuous cycle of stress management, glycemic control, and immune modulation. Furthermore, we examine the actual utilization of MBI during the COVID-19 pandemic era through recent studies. With proper online education, non-pharmacological MBI may be more widely used as an important tool for self-health care that complements the usual treatment of COVID-19 patients and survivors.

The Potential Roles of Probiotics, Resistant Starch, and Resistant Proteins in Ameliorating Inflammation during Aging (Inflammaging)

Aging is typically accompanied by biological and physiological changes that alter cellular functions. Two of the most predominant phenomena in aging include chronic low-grade inflammation (inflammaging) and changes in the gut microbiota composition (dysbiosis). Although a direct causal relationship has not been established, many studies have reported significant reductions in inflammation during aging through well-maintained gut health and microbial balance. Prebiotics and probiotics are known to support gut health and can be easily incorporated into the daily diet. Unfortunately, few studies specifically focus on their significance in reducing inflammation during aging. Therefore, this review summarizes the scientific evidence of the potential roles of probiotics and two types of prebiotics, resistant starch and resistant proteins, in later age. Studies have demonstrated that the oral consumption of bacteria that may contribute to anti-inflammatory response, such as Bifidobacterium spp., Akkermansia munichipilla, and Faecalis praunitzii, contributes significantly to the suppression of pro-inflammatory markers in elderly humans and aged animals. Colonic fermentation of resistant starch and proteins also demonstrates anti-inflammatory activity owing to the production of butyrate and an improvement in the gut microbiota composition. Collectively, probiotics, resistant starch, and resistant proteins have the potential to promote healthy aging.

Mindfulness interventions for offsetting health risk following early life stress: Promising directions

Early life stress (ELS), common to childhood maltreatment, socioeconomic disadvantage, and racial discrimination, is thought to create a proinflammatory phenotype that increases risk for poor health in adulthood. Systemic change is needed to address the root causes of ELS, but a substantial number of adults are already at increased health risk by virtue of ELS exposure. Interventions that target stress pathways have the potential to interrupt the trajectory from ELS to inflammatory disease risk in adulthood. Mindfulness-based interventions (MBIs), which train acceptance toward present-moment experience, have shown promise for reducing stress and improving a variety of stress-sensitive health outcomes. Although MBIs have primarily been conducted in more advantaged populations, evidence suggests that they may be uniquely effective for improving mental health and health-related quality of life among those with a history of ELS. Whether these effects extend to physical health remains unknown. To shed light on this question, I review evidence that MBIs influence inflammatory markers in at-risk samples, explore the promise of MBIs for improving stress-related health outcomes in diverse at-risk populations, and describe adaptations to MBIs that may increase their acceptability and efficacy in populations exposed to ELS. This prior work sets the stage for well-controlled RCTs to evaluate whether MBIs influence stress and inflammatory pathways among those exposed to ELS and for pragmatic and implementation trials focused on disseminating MBIs to reach these at-risk populations. Overall, the evidence assembled here shows the potential of MBIs for offsetting physical health risk related to ELS.