The MCP-4/MCP-1 ratio in plasma is a candidate circadian biomarker for chronic post-traumatic stress disorder

Causal Relationship Between Post-Traumatic Stress Disorder and Immune Cell Traits: A Mendelian Randomization Study

INTRODUCTION

Post-traumatic stress disorder (PTSD) is a debilitating psychological disorder that occurs after exposure to catastrophic-level experiences. Although alterations in immune function have been identified in individuals with PTSD, the causal relationship between the two remains unclear.

METHODS

To investigate the causal relationship between PTSD and immune function, we conducted the forward and backward two-sample Mendelian randomization (MR) analyses, based on summary-level genome-wide association studies (GWAS) data on PTSD and immune cell traits.

RESULTS

For the forward MR analysis, PTSD was found to reduce the levels of CD62L- dendritic cell (DC) (beta = -0.254, FDR = 0.01), CD86+ myeloid DC (beta = -0.238, FDR = 0.014), CD62L- myeloid DC (beta = -0.26, FDR = 0.01), CD62L- CD86+ myeloid DC absolute count (beta = -0.264, FDR = 0.024), and CD62L- CD86+ myeloid DC (beta = -0.328, FDR = 0.002). In contrast, PTSD was observed to increase the level of CD28- CD8dim T-cell absolute count (beta = 0.27, FDR = 0.029). For the backward MR analysis, the odds ratio (OR) for CD33 on CD33dim HLA DR+ CD11b- in relation to PTSD risk was found to be 1.045 (95% CI = 1.021-1.069, FDR = 0.008). The OR for FSC-A on HLA DR+ CD8br was 1.048 (95% CI = 1.018-1.079, FDR = 0.039) and for CCR2 on CD14- CD16+ monocyte was 1.059 (95% CI = 1.027-1.092, FDR = 0.008). No significant pleiotropy was detected in both forward and backward MR analyses.

CONCLUSION

The bidirectional MR study shed light on the intricate interplay between immune function and PTSD. The identification of a bidirectional causal relationship between T cells and PTSD opens new avenues for considering innovative approaches to the prevention and early intervention of PTSD.

Objective Response of Saliva Biomarkers After High-Stress and Mass Casualty Scenarios: A Pilot Study

INTRODUCTION

Surgeons and military personnel are subjected to high-stress scenarios, which leads to greater rates of burnout. There is room to optimize performance and longevity in these careers by better understanding the body's stress response and applying it to stress management training. This study aims to understand the physiological response in those engaged in trauma scenarios by examining 6 hormones and 42 cytokines during the Intensive Surgical and Trauma Skills Course held at Strategic Operations Inc in San Diego, CA.

METHODS

Thirty-seven military medical students participated in full immersion, hyper-realistic, and experiential mass casualty high-stress scenarios. Participants were exposed to both operating and emergency room scenarios. Saliva samples were taken after stress inoculation (postinoculation) and again 1 hr after each scenario (recovery). Saliva samples were analyzed using plex assays from Eve Technologies. Data were grouped and analyzed by location and timing using mixed effect nonlinear models. Distributions were compared by location and were analyzed with respect to biomarker levels over the 4-day training period.

RESULTS

For emergency room scenarios, there was a decrease in the following cytokines from postinoculation to recovery: epidermal growth factor (EGF), granulocyte colony stimulating factor (G-CSF), epidermal growth factor, granulocyte colony stimulating factor, interleukin 1alpha (IL-1α), interleukin 1beta (IL-1 β), IL-1RA, IL-4, IL-8, IL-10, IL-18, monocyte chemotactic protein (MCP) 1, macrophage colony stimulating factor (M-CSF), macrophage derived chemokine (MDC), CXC motif ligand 9 (MIG/CXCL9), regulated upon activation, normal T cell expressed and secreted (RANTES), and vascular endothelial growth factor (P < 0.05, t > 3.0). For operating room scenarios, there was a decrease in the following cytokines: EGF, G-CSF, IL-1α, IL-1 β, IL-1RA, IL-6, IL-8, IL-10, IL-18, M-CSF, MDC, MIG/CXCL9, RANTES, and tumor necrosis factor alpha. In operating room scenarios, an increase in the hormone levels of progesterone and triodothyronine were observed. The cytokines observed in both groups included EGF, IL-1α, RANTES, MDC, EGF, G-CSF, IL-1RA, IL-18, MIG/CXCL9, IL-8, IL-1β, M-CSF, and IL-10. These significant biomarkers were also graphed and visualized as variable throughout the week.

CONCLUSIONS

These preliminary data narrow a wide array of stress biomarkers to a smaller, significant group. Surgeons and military personnel are subjected to extraordinary levels of stress with narrow margins for error. To optimize performance and outcomes, it is pertinent to understand the physiological stress response. Future investigation and pairing of cytokine measurements with neuropsychological and performance-based testing will target opportunities to direct training and identify profiles of individuals well suited for stressful environments.

Exploring the interplay between posttraumatic stress disorder, gut microbiota, and inflammatory biomarkers: a comprehensive meta-analysis

Introduction

Posttraumatic stress disorder (PTSD) is the most common mental health disorder to develop following exposure to trauma. Studies have reported conflicting results regarding changes in immune biomarkers and alterations in the abundance of bacterial taxa and microbial diversity in patients with PTSD.

Aim

The purpose of this meta-analysis is to summarize existing studies examining gut microbiota characteristics and changes in immune biomarkers in patients with PTSD.

Methods

Relevant studies were systematically searched in PubMed, Scopus, and Embase, published in English between January 1, 1960, and December 1, 2023. The outcomes included changes in abundance and diversity in gut microbiota (gut microbiota part) and changes in immune biomarkers (immune part).

Results

The meta-analysis included a total of 15 studies, with 9 focusing on changes in inflammatory biomarkers and 6 focusing on changes in gut microbiota composition in patients with PTSD. No differences were observed between groups for all inflammatory biomarkers (P≥0.05). Two of the six studies found that people with PTSD had less alpha diversity. However, the overall Standardized Mean Difference (SMD) for the Shannon Diversity Index was not significant (SMD 0.27, 95% CI -0.62-0.609, p = 0.110). Regarding changes in abundance, in two of the studies, a significant decrease in Lachnospiraceae bacteria was observed.

Conclusion

This meta-analysis provides a comprehensive overview of gut microbiota characteristics in PTSD, suggesting potential associations with immune dysregulation. Future research should address study limitations, explore causal relationships, and consider additional factors influencing immune function in individuals with PTSD.

Systematic review registration

https://www.crd.york.ac.uk, identifier CRD42023476590.

Altered serum TNF-α and MCP-4 levels are associated with the pathophysiology of major depressive disorder: A case-control study results

BACKGROUND

Major Depressive Disorder (MDD) is a debilitating mental health condition with complex etiology, and recent research has focused on pro-inflammatory cytokines and chemokines as potential contributors to its pathogenesis. However, studies investigating the roles of TNF-α and MCP-4 in MDD within the Bangladeshi population are scarce. This study aimed to assess the association between serum TNF-α and MCP-4 levels and the severity of MDD, exploring their potential as risk indicators for MDD development.

METHODS

This case-control study enrolled 58 MDD patients from Bangabandhu Sheikh Mujib Medical University (BSMMU) Hospital, Dhaka, Bangladesh, alongside 30 age, sex, and BMI-matched healthy controls. MDD diagnosis followed DSM-5 criteria and disease severity using the 17-item Hamilton Depression Rating Scale (Ham-D). We measured serum TNF-α and MCP-4 levels using ELISA assays according to the supplied protocols.

RESULTS

The study revealed significantly elevated serum TNF-α levels in MDD patients (47±6.6 pg/ml, mean±SEM) compared to controls (28.06±1.07 pg/ml). These increased TNF-α levels positively correlated with Ham-D scores (Pearson's r = 0.300, p = 0.038), suggesting a potential association between peripheral TNF-α levels and MDD pathology. Additionally, MDD patients exhibited significantly higher serum MCP-4 levels (70.49±6.45 pg/ml) than controls (40.21±4.08 pg/ml). However, serum MCP-4 levels showed a significant negative correlation (r = -0.270, P = 0.048) with Ham-D scores in MDD patients, indicating a more complex role for MCP-4 in MDD pathogenesis.

CONCLUSION

This study highlights that Bangladeshi MDD patients exhibit heightened inflammatory and immune responses compared to controls, supporting the cytokine hypothesis in MDD pathogenesis. Serum TNF-α, but not MCP-4, shows promise as a potential biomarker for assessing the risk of MDD development, which could aid in early detection. Future investigations involving larger populations and longitudinal studies are essential to confirm the utility of these cytokines as biomarkers for MDD.

CCL2-mediated inflammatory pathogenesis underlies high myopia-related anxiety

High myopia is a leading cause of blindness worldwide. It may lead to emotional defects that rely closely on the link between visual sensation and the central nervous system. However, the extent of the defects and its underlying mechanism remain unknown. Here, we report that highly myopic patients exhibit greater anxiety, accompanied by higher CC chemokine ligand 2 (CCL2) and monocyte levels in the blood. Similar findings are found in the mouse model of high myopia. Mechanistic evaluations using GFP-positive bone marrow chimeric mice, parabiotic mouse model, enhanced magnetic resonance imaging, etc., show that highly myopic visual stimulation increases CCL2 expression in eyes, aggravates monocyte/macrophage infiltration into eyes and brains, and disrupts blood-ocular barrier and blood-brain barrier of mice. Conversely, Ccl2-deficient highly myopic mice exhibit attenuated ocular and brain infiltration of monocytes/macrophages, reduced disruption of the blood-ocular barrier and blood-brain barrier, and less anxiety. Substantial alleviation of high myopia-related anxiety can also be achieved with the administration of CCL2-neutralizing antibodies. Our results establish the association between high myopia and anxiety, and implicate the CCL2-mediated inflammatory pathogenesis as an underlying mechanism.

A Pilot Study of a Three-Session Heart Rate Variability Biofeedback Intervention for Veterans with Posttraumatic Stress Disorder

Many veterans do not complete traditional trauma treatments; others may continue to struggle with posttraumatic stress disorder (PTSD) even after completing a full course of therapy (Blasé et al., in Int J Environ Res Public Health 18(7):Article 3329, https://doi.org/10.3390/ijerph18073329 , 2016). Heart rate variability (HRV) biofeedback (HRVB) is a non-invasive, non-pharmacological, breathing-based cardiorespiratory training technique that can reduce trauma symptoms and improve HRV parameters. Prior studies have demonstrated HRVB is well-tolerated by veterans with PTSD symptoms (Tan et al., in Appl Psychophysiol Biofeedback 36(1):27-35, 10.1007/s10484-010-9141-y, 2011; Schuman and Killian, in Appl Psychophysiol Biofeedback 44(1):9-20, https://doi.org/10.1007/s10484-018-9415-3 , 2019). This randomized wait-list controlled pilot study tested a short mobile app-adapted HRVB intervention in combination with treatment as usual for veterans with military-related PTSD to determine if further investigation was warranted. We assessed veterans' military-related PTSD symptoms, depression symptoms, and HRV time and frequency domain measures at baseline, after three clinical sessions, and one month later. This study combined clinical training and home biofeedback with a smartphone app and sensor to reinforce training and validate adherence. In the intervention group, depression and SDNN significantly improved, and we observed marginally significant improvements for PTSD Cluster B (intrusion) symptoms, whereas no significant improvements were observed in the control group. In addition, the brief protocol was acceptable to veterans with PTSD with over 83% of participants completing the study. However, adherence to home practice was low. Findings suggest brief HRVB interventions can decrease comorbid depression and improve overall autonomic function in veterans with PTSD; however, additional research on home biofeedback is necessary to determine the best strategies to increase adherence and which veterans would benefit from brief HRVB interventions.

Metabolic and Inflammatory Response in Post-Traumatic Stress Disorder (PTSD): A Systematic Review on Peripheral Neuroimmune Biomarkers

Several heterogeneous pathophysiology pathways have been hypothesized for being involved in the onset and course of Post-Traumatic Stress Disorder (PTSD). This systematic review aims to summarize the current evidence on the role of inflammation and immunological dysregulations in PTSD, investigating possible peripheral biomarkers linked to the neuroimmune response to stress. A total of 44 studies on the dysregulated inflammatory and metabolic response in subjects with PTSD with respect to controls were included. Eligibility criteria included full-text publications in the English language, human adult samples, studies involving both subjects with a clinical diagnosis of PTSD and a healthy control group. The research was focused on specific blood neuroimmune biomarkers, namely IL-1β, TNF-α, IL-6 and INF-γ, as well as on the potential harmful role of reduced antioxidant activity (involving catalase, superoxide dismutase and glutathione peroxidase). The possible role of the inflammatory-altered tryptophan metabolism was also explored. The results showed conflicting data on the role of pro-inflammatory cytokines in individuals with PTSD, and a lack of study regarding the other mediators investigated. The present research suggests the need for further studies in human samples to clarify the role of inflammation in the pathogenesis of PTSD, to define potential peripheral biomarkers.

CCL13 and human diseases

CCL13/MCP-4 belongs to the CC chemokine family, which induces chemotaxis in many immune cells. Despite extensive research into its function in numerous disorders, a thorough analysis of CCL13 is not yet accessible. The role of CCL13 in human disorders and existing CCL13-focused therapies are outlined in this study. The function of CCL13 in rheumatic diseases, skin conditions, and cancer is comparatively well-established, and some studies also suggest that it may be involved in ocular disorders, orthopedic conditions, nasal polyps, and obesity. We also give an overview of research that found very little evidence of CCL13 in HIV, nephritis, and multiple sclerosis. Even though CCL13-mediated inflammation is frequently linked to disease pathogenesis, it's fascinating to note that in some conditions, like primary biliary cholangitis (PBC) and suicide, it might even act as a preventative measure.

Prognostic biomarker MCP-4 triggers epithelial-mesenchymal transition via the p38 MAPK pathway in ovarian cancer

BACKGROUND

Monocyte chemoattractant protein-4 (MCP-4/CCL13) is a proinflammatory factor that is overexpressed in various malignant tumors and may play an important role in tumor progression and metastasis. However, its role and mechanism of action in ovarian cancer remains unknown.

METHODS

Immunohistochemistry (IHC) was performed to detect the expression of MCP-4 in ovarian cancer tissues, and the effect of MCP-4 on patient survival and prognosis was analyzed. Overexpression and suppression of MCP-4 in ovarian cancer cell lines were then established, and their effects on cell invasion, migration, and apoptosis were studied. ES-2 cell lines were employed to establish a peritoneal dissemination model in nude mice. Western blotting was performed to detect the expression of epithelial mesenchymal transition (EMT) markers and the p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway.

RESULTS

MCP-4 was highly expressed in ovarian cancer tissues and its expression level was related to the prognosis of patients with ovarian cancer. MCP-4 overexpression promoted the migration and invasion of ovarian cancer cells but inhibited apoptosis. MCP-4 overexpression increased the expression of MMP-2, MMP-9, N-cadherin, vimentin and Bcl2/Bax and decreased the expression of E-cadherin. MCP-4 overexpression increased the phosphorylation of the p38 MAPK pathway. The inhibition of MCP-4 expression indicated an opposite trend. In vivo experiments have also confirmed that MCP-4 overexpression can promote metastasis of ovarian cancer.

CONCLUSION

MCP-4 promotes ovarian cancer progression through the p38 MAPK signaling pathway, and may be a potential biomarker and therapeutic target for ovarian cancer.

Inflammatory and oxidative stress markers in post-traumatic stress disorder: a systematic review and meta-analysis

Post-traumatic stress disorder (PTSD) has been associated with persistent, low-degree inflammation, which could explain the increased prevalence of autoimmune conditions and accelerated aging among patients. The aim of the present study is to assess which inflammatory and oxidative stress markers are associated with PTSD. We carried out a meta-analytic and meta-regression analysis based on a systematic review of studies comparing inflammatory and oxidative stress markers between patients with PTSD and controls. We undertook meta-analyses whenever values of inflammatory and oxidative stress markers were available in two or more studies. Overall, 28,008 abstracts were identified, and 54 studies were included, with a total of 8394 participants. The Newcastle-Ottawa Quality Assessment Scale was used to evaluate the quality of the studies. Concentrations of C-reactive protein (SMD = 0.64; 95% CI: 0.21 to 1.06; p = 0.0031; k = 12), interleukin 6 (SMD = 0.94; 95% CI: 0.36 to 1.52; p = 0.0014; k = 32), and tumor necrosis factor-α (SMD = 0.89; 95% CI: 0.23 to 1.55; p = 0.0080; k = 24) were significantly increased in patients with PTSD in comparison with healthy controls. Interleukin 1β levels almost reached the threshold for significance (SMD = 1.20; 95% CI: -0.04 to 2.44; p = 0.0569; k = 15). No oxidative stress marker was associated with PTSD. These findings may explain why PTSD is associated with accelerated aging and illnesses in which immune activation has a key role, such as cardiovascular diseases and diabetes. In addition, they pointed to the potential role of inflammatory markers as therapeutic targets.

Monocyte chemoattractant protein-1 levels are associated with major depressive disorder

OBJECTIVES

Major depressive disorder (MDD) is a distressing condition characterized by persistent low mood, loss of interest in daily activities. Researchers consider several biological, psycho-social, and genetic factors are involved in depression. The present study aimed to investigate the serum levels of monocyte chemoattractant protein-1 (MCP-1) in MDD patients to explore its role in depression.

METHODS

This case-control study recruited 114 MDD patients and 106 healthy controls (HCs) matched by age and gender. A specialized psychiatrist diagnosed the cases and evaluated the controls based on the diagnostic and statistical manual for mental disorders, 5th edition. We quantified serum MCP-1 levels using commercially available enzyme-linked immune sorbent assay kits. Also, we applied the Hamilton depression rating scale (Ham-D) to measure the severity of depression.

RESULTS

We observed the decreased levels of serum MCP-1 in MDD patients compared to HCs. Also, we obtained a significant negative correlation between serum MCP-1 levels and Ham-D scores. Moreover, female MDD patients with higher Ham-D scores exhibited lower serum MCP-1 levels. The receiver operating characteristic analysis demonstrated the good diagnostic value of MCP-1 with the area under the curve at 0.837.

CONCLUSIONS

The depression-related alteration of serum MCP-1 may be more complicated than the current assumption and depends on the characteristics of the individual patients. Our study suggests that the serum MCP-1 levels might involve in the pathophysiology and mechanism of MDD. The present findings, along with the diagnostic evaluation, might be used to evaluate depressive patients.

Chemokine profile in women with moderate to severe anxiety and depression during pregnancy

Background

Cytokine levels have been extensively described in pregnant subjects under normal and pathological conditions, including mood-related disorders. Concerning chemokines, very few studies have reported their association with psychiatric disorders during pregnancy. Therefore, we explored the chemokine profile in women exhibiting anxiety and depression during late pregnancy in the present study.

Methods

One hundred twenty-six pregnant women in the 3rd trimester of pregnancy, displaying moderate to severe anxiety (ANX) alone and women exhibiting moderate to severe anxiety with comorbid depression (ANX + DEP), and 40 control pregnant women without affective disorders (CTRL) were evaluated through the Hamilton Anxiety Rating Scale (HARS) and the Hamilton Depression Rating Scale (HDRS). Serum chemokine levels of MCP-1 (CCL2), RANTES (CCL5), IP-10 (CXCL10), Eotaxin (CCL11), TARC (CCL17), MIP-1α (CCL3), MIP-1β (CCL4), MIG (CXCL9), MIP-3α (CCL20), ENA-78 (CXCL5), GROα (CXCL1), I-TAC (CXCL11) and IL-8 (CXCL8)] were measured by immunoassay. Clinical, biochemical, and sociodemographic parameters were correlated with HARS and HDRS score values.

Results

Serum levels of most chemokines were significantly higher in the ANX and in the ANX + DEP groups, when compared to the CTRL group. Positive correlations were observed between MIP-1α/CCL3, MIP-1β/CCL4, MCP-1/CCL2, MIP-3α/CCL20, RANTES/CCL5, Eotaxin/CCL11, and I-TAC/CXCL11 with high scores for anxiety (HARS) (p < 0.05) and for depression (HDRS) (p < 0.004). After controlling clinical measures for age + gwk + BMI, chemokines such as IL-8/CXCL8, MCP-1/CCL2 and MIP-1β/CCL4 were found associated with high scores for anxiety (p < 0.05) in the ANX group. TARC/CCL17 and Eotaxin/CCL11 showed significant associations with high scores for depression (p < 0.04) whereas, MCP-1/CCL2 and MIP-1α/CCL3 were significantly associated with high scores for anxiety (p < 0.05) in the ANX + DEP group. Using a multivariate linear model, high serum levels of MIP-1β/CCL4 and Eotaxin/CCL11 remained associated with depression (p < 0.01), while, IL-8/CXCL8, MIP-1β/CCL4, MCP-1/CCL2, and MIP-1α/CCL3 were associated with anxiety (p < 0.05) in the symptomatic groups.

Conclusions

Our data show that serum levels of distinct chemokines are increased in women exhibiting high levels of affective symptoms during late pregnancy. Our results suggest that increased levels of anxiety, depressive symptoms, and mood-related disorders may promote changes in specific functional chemokines associated with a chronic inflammatory process. If not controlled, it may lead to adverse obstetric and negative neonate outcomes, child development and neuropsychiatric alterations in the postnatal life.

Highlights

Chemokine levels increase in affective disorders during pregnancy.

MCP-1: Function, regulation, and involvement in disease

MCP-1 (Monocyte chemoattractant protein-1), also known as Chemokine (CC-motif) ligand 2 (CCL2), is from family of CC chemokines. It has a vital role in the process of inflammation, where it attracts or enhances the expression of other inflammatory factors/cells. It leads to the advancement of many disorders by this main mechanism of migration and infiltration of inflammatory cells like monocytes/macrophages and other cytokines at the site of inflammation. MCP-1 has been inculpated in the pathogenesis of numerous disease conditions either directly or indirectly like novel corona virus, cancers, neuroinflammatory diseases, rheumatoid arthritis, cardiovascular diseases. The elevated MCP-1 level has been observed in COVID-19 patients and proven to be a biomarker associated with the extremity of disease along with IP-10. This review will focus on involvement and role of MCP-1 in various pathological conditions.

Circulating cytokine levels in the treatment of comorbid anxiety disorders

Psychotherapy research aims to investigate predictors and moderators of treatment outcome, but there are few consistent findings. This study aimed to investigate cytokines in patients undergoing treatment for anxiety disorders and whether the level of cytokines moderated the treatment outcome. Thirty-seven patients with comorbid and treatment-resistant anxiety disorders were investigated using multilevel modelling. Serum cytokine levels were measured three times: pretreatment, in the middle of treatment, and at the end of treatment. Anxiety and metacognitions were measured weekly throughout treatment by self-report. The levels of monocyte chemoattractant protein-1, tumour necrosis factor-alpha, and interleukin-1 receptor antagonist did not change during therapy or were not related to the level of anxiety. Metacognitive beliefs predicted anxiety, but the relationship between metacognitions and anxiety was not moderated by cytokines. Limitations of the study include that the patients were not fasting at blood sampling, and we did not assess body mass index, which may affect cytokine levels. The lack of significance for cytokines as a predictor or moderator may be due to a lack of power for testing moderation hypotheses, a problem associated with many psychotherapy studies. Cytokines did not predict the outcome in the treatment of comorbid anxiety disorders in our sample. Furthermore, cytokines did not moderate the relationship between metacognitions and anxiety.

Chemokines in post-traumatic stress disorder: A network meta-analysis

BACKGROUND

Previous studies on the association between chemokines concentrations and post-traumatic stress disorder (PTSD) yielded inconsistent results. Therefore, the purpose of this network meta-analysis was to summarize these results.

METHODS

The databases of PubMed, Web of Science, Psyc-ARTICLES, Embase and Cochrane Library were searched for relevant articles published not later than January 15, 2020. Then, eligible studies were selected based on predefined study selection criteria. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated as group differences in chemokines concentrations. Moreover, network meta-analysis was used to rank chemokines effect values according to their respective surface under cumulative ranking curve (SUCRA) probabilities.

FINDINGS

A total of 18 eligible studies that investigated the association between 9 different chemokines and PTSD were identified. They involved 1,510 patients and 2,012 controls. Results of the meta-analysis showed that the concentrations of CCL3, CCL4 and CCL5 in the PTSD patients were significantly higher than that in the controls (SMDs of 4.12, 6.11 and 1.53 respectively). However, although not statistically significant, concentrations of CCL2 tended to be lower in PTSD patients than in the controls (SMD = -0.76); whereas concentrations of CXCL12 tended to be higher in PTSD patients than in the controls (SMD = 0.37). SUCRA probabilities showed that, among all the chemokines studied, the effect of CCL5 was the highest in PTSD patients.

INTERPRETATION

Concentrations of CCL3, CCL4 and CCL5 may be associated with a trauma and/or PTSD. Also, CXCL12 and CCL2 may be the underlying biomarkers for trauma and/or PTSD. Thus, future studies with large population based samples are needed to further assess these associations. In addition, future research should explore possible mechanisms underlying these associations, with the aim to develop new diagnostics for PTSD. PROSPERO CRD42019147703.

Immune biomarkers alterations in post-traumatic stress disorder: A systematic review and meta-analysis

BACKGROUND

Studies have reported the changes of immune biomakers in post-traumatic stress disorder (PTSD), but the results were conflicting. Our aim was to investigate the changes of immune biomarkers in PTSD.

METHODS

Literatures investigating the changes of immune markers in PTSD published in English were systematically searched through PubMed, Embase and Web of Science. We conducted random effects meta-analyses relating PTSD to immune biomarker concentrations and using subgroup analyses to resolve heterogeneity.

RESULTS

A total of 2606 articles were screened and 42 samples were included by the systematic review. The levels of interleukin-1β (IL-1β, P = 0.01), IL-2 (P = 0.006), IL-6 (P = 0.0002), interferon-γ (IFN-γ, P = 0.004), tumor necrosis factor-α (TNF-α, P = 0.004), C-reactive protein (CRP, P = 0.0003) and white blood cell (WBC, P = 0.01) were higher in PTSD than healthy controls (HC). Subgroup meta-analyses for psychotropic medication showed the levels of IL-1β and IL-2 were not increased in the PTSD. Subgroup meta-analyses for whether HC exposed to trauma showed the levels of IL-1β and IL-6 were not increased in the PTSD. Egger´s test revealed there was no publication bias. However, there was significant heterogeneity across studies for immune markers other than for WBC (P = 0.14, I² = 45%). Subgroup analyses based on sex, HC exposed to trauma, PTSD comorbid major depressive disorder, PTSD on psychotropic medications partially or completely resolved heterogeneity for some immune biomarkers.

CONCLUSION

This meta-analysis provides evidence for elevation of IFN-γ, TNF-α, CRP, and WBC in PTSD.

Inflammation in Post-Traumatic Stress Disorder (PTSD): A Review of Potential Correlates of PTSD with a Neurological Perspective

Post-traumatic stress disorder (PTSD) is a chronic condition characterized by symptoms of physiological and psychosocial burden. While growing research demonstrated signs of inflammation in PTSD, specific biomarkers that may be representative of PTSD such as the detailed neural correlates underlying the inflammatory responses in relation to trauma exposure are seldom discussed. Here, we review recent studies that explored alterations in key inflammatory markers in PTSD, as well as neuroimaging-based studies that further investigated signs of inflammation within the brain in PTSD, as to provide a comprehensive summary of recent literature with a neurological perspective. A search was conducted on studies published from 2009 through 2019 in PubMed and Web of Science. Fifty original articles were selected. Major findings included elevated levels of serum proinflammatory cytokines in individuals with PTSD across various trauma types, as compared with those without PTSD. Furthermore, neuroimaging-based studies demonstrated that altered inflammatory markers are associated with structural and functional alterations in brain regions that are responsible for the regulation of stress and emotion, including the amygdala, hippocampus, and frontal cortex. Future studies that utilize both central and peripheral inflammatory markers are warranted to elucidate the underlying neurological pathway of the pathophysiology of PTSD.

Increased peripheral levels of TARC/CCL17 in first episode psychosis patients

BACKGROUND

Evidence for a link between the pathophysiology of schizophrenia and the immune system is mounting. Altered levels of chemokines in plasma have previously been reported in patients with schizophrenia under antipsychotic medication. Here we aimed to study both peripheral and central chemokine levels in drug-naïve or short-time medicated first episode psychosis (FEP) patients.

METHOD

We analyzed nine chemokines in plasma and CSF from 41 FEP patients and 22 healthy controls using electrochemiluminescence assay.

RESULTS

In plasma four chemokines; TARC/CCL17, eotaxin/CCL11, MDC/CCL22, IP-10/CXCL10 and in CSF one chemokine; IP-10/CXCL10 showed reliable detection in >50% of the cases. FEP patients displayed increased levels of TARC/CCL17 in plasma compared to healthy controls, 89.6 (IQR 66.2-125.8) pg/mL compared to 48.6 (IQR 28.0-71.7) pg/mL (p = 0.001). The difference was not attributed to confounding factors. Plasma TARC/CCL17 was not associated with PANSS, CGI or GAF scores, neither with cognitive functions. The chemokines eotaxin/CCL11, MDC/CCL22, IP-10/CXCL10 in plasma and IP-10/CXCL10 in CSF did not differ between FEP patients and controls.

CONCLUSION

In line with a previous study showing that chronic patients with schizophrenia display increased plasma TARC/CCL17 levels, we here found an elevation in FEP patients suggesting a role of TARC/CCL17 in early stages of schizophrenia. The exact mechanism of this involvement is still unknown and future longitudinal studies as well as studies of central and peripheral chemokine levels would be of great interest.

Repeated Changes to the Gravitational Field Negatively Affect the Serum Concentration of Select Growth Factors and Cytokines

Space flights, some physical activities, and extreme sports can greatly alter the gravitational forces experienced by the body. Being a deviation from the constant pull of Earth, these alterations can be considered gravitational stress and have the potential to affect physiological processes. Physical cues play a vital role in the homeostasis and function of the immune system. The effect of recurrent alterations of the gravitational pull on the levels of soluble mediator such as cytokines is unknown. Parabolic flights provide a controlled environment and make these a suitable model to study the effects of gravitational stress. Utilizing this model, we evaluated the effects of short-term gravitational stress on serum concentration of cytokines and other soluble mediators. Blood was taken from 12 healthy volunteers immediately before the first parabola and immediately after the last. Samples taken on the ground at corresponding time points the day before were used to control for circadian effects. A wide range of soluble mediators was analyzed using a multiplex bead assay. We found that the rate-change of eight molecules was significantly affected by the parabolic flight. Among other functions, these molecules, EGF, PDGF-AA, PDGF-BB, HGF, IP-10, Eotaxin (CCL11), TARC, and Angiopoietin-2, can be associated with bone remodeling and immune activation. It is therefore possible that gravitational stress can have clinically relevant impact on the control of a wide range of physiological processes.

Reduced Expression of Immune Mediators by T-Cell Subpopulations of Combat-Exposed Veterans With Post-Traumatic Stress Disorder

Post-traumatic stress disorder (PTSD) has been suggested to be associated with an inflammatory immune state, although few studies have examined peripheral blood lymphocytes in subjects that have PTSD and compared immune parameters to subjects that experienced similar trauma, but did not develop PTSD. An exploratory approach was undertaken to compare phenotypes of blood CD4⁺ and CD8⁺ subpopulations and their expression of immune mediators between Veterans of the Iraq and Afghanistan wars who experienced similar levels of combat, with some developing PTSD and other not. The results of this study did not demonstrate evidence of enhanced immune activation of peripheral blood lymphocytes. Instead, the results showed a decline in expression of the pro-inflammatory mediator IFN-γ and the cytotoxin granzyme B in CD8⁺ subpopulations from Veterans with PTSD. While the reductions in expression of IFN-γ and granzyme B did not reach statistical significance when examining the CD8⁺ cell population as a whole, the declines were significant when examining the CD8⁺ cell subpopulations, with different mediators being reduced in different subpopulations. The most prominent decline in IFN-γ expression was by the unconventional CD8^dimCD3⁺ T-cell subpopulation that has been associated with chronic infection and immune fatigue. The decline in granzyme B was most prominent in the NK-containing CD8^dimCD3^- subpopulation of Tcells. Consequently, analysis of blood leukocyte subpopulations, rather than bulk lymphocyte groups, reveals a dampened level of immune reactivity in combat-exposed Veterans with PTSD compared to combat-exposed Veterans without PTSD.

Blood biomarkers are associated with brain function and blood flow following sport concussion

BACKGROUND

Secondary injury pathophysiology after sport-related concussion (SRC) is poorly understood. Blood biomarkers may be a useful tool for characterizing these processes, yet there are limitations in their application as a single modality. Combining blood biomarker analysis with advanced neuroimaging may help validate their continued utility in brain injury research by elucidating important secondary injury mechanisms. Hence, the purpose of this study was to evaluate co-modulation between peripheral blood biomarkers and advanced functional brain imaging after SRC.

METHODS

Forty-three university level athletes from 7 sports were recruited (16 recently concussed athletes; 15 healthy athletes with no prior history of concussion; 12 healthy athletes with a history of concussion). Seven blood biomarkers were evaluated: s100B, total tau (T-tau), von Willebrand factor (vWF), brain derived neurotrophic factor (BDNF), peroxiredoxin (PRDX)-6, monocyte chemoattractant protein (MCP)-1 and -4. Resting-state functional MRI was employed to assess global neural connectivity (Gconn), and arterial spin labelling was used to evaluate cerebral blood flow (CBF). We tested for concurrent alterations in blood biomarkers and MRI measures of brain function between athlete groups using a non-parametric, bootstrapped resampling framework.

RESULTS

Compared to healthy athletes, recently concussed athletes showed greater concurrent alterations in several peripheral blood biomarker and MRI measures: a decrease in T-Tau and Gconn, a decrease in T-Tau and CBF, a decrease in Gconn with elevated PRDX-6, a decrease in CBF with elevated PRDX-6, and a decrease in Gconn with elevated MCP-4. In addition, compared to healthy athletes with no concussion history, healthy athletes with a history of concussion displayed greater concurrent alterations in blood biomarkers and Gconn; lower GConn covaried with higher blood levels of s100B and MCP-4.

CONCLUSION

We identified robust relationships between peripheral blood biomarkers and MRI measures in both recently concussed athletes and healthy athletes with a history of concussion. The results from this combinatorial approach further support that human concussion is associated with inflammation, oxidative stress, and cellular damage, and that physiological perturbations may extend chronically beyond recovery. Finally, our results support the continued implementation of blood biomarkers as a tool to investigate brain injury, particularly in a multimodal framework.

Vitamin C in Stem Cell Biology: Impact on Extracellular Matrix Homeostasis and Epigenetics

Transcription factors and signaling molecules are well-known regulators of stem cell identity and behavior; however, increasing evidence indicates that environmental cues contribute to this complex network of stimuli, acting as crucial determinants of stem cell fate. l-Ascorbic acid (vitamin C (VitC)) has gained growing interest for its multiple functions and mechanisms of action, contributing to the homeostasis of normal tissues and organs as well as to tissue regeneration. Here, we review the main functions of VitC and its effects on stem cells, focusing on its activity as cofactor of Fe⁺²/αKG dioxygenases, which regulate the epigenetic signatures, the redox status, and the extracellular matrix (ECM) composition, depending on the enzymes' subcellular localization. Acting as cofactor of collagen prolyl hydroxylases in the endoplasmic reticulum, VitC regulates ECM/collagen homeostasis and plays a key role in the differentiation of mesenchymal stem cells towards osteoblasts, chondrocytes, and tendons. In the nucleus, VitC enhances the activity of DNA and histone demethylases, improving somatic cell reprogramming and pushing embryonic stem cell towards the naive pluripotent state. The broad spectrum of actions of VitC highlights its relevance for stem cell biology in both physiology and disease.