Development of depressive symptoms post hip fracture is associated with altered immunosuppressive phenotype in regulatory T and B lymphocytes

Causal role of immune cells in major depressive disorder and bipolar disorder: Mendelian randomization (MR) study

BACKGROUND

Major depressive disorder (MDD) and bipolar disorder (BD) are prevalent psychiatric conditions linked to inflammatory processes. However, it is unclear whether associations of immune cells with these disorders are likely to be causal.

METHODS

We used two-sample Mendelian randomization (MR) approach to investigate the relationship between 731 immune cells and the risk of MDD and BD. Rigorous sensitivity analyses are conducted to assess the reliability, heterogeneity, and horizontal pleiotropy of the findings.

RESULTS

Genetically-predicted CD27 on IgD+ CD38- unswitched memory B cell (inverse variance weighting (IVW): odds ratio (OR) [95 %]: 1.017 [1.007 to 1.027], p = 0.001), CD27 on IgD+ CD24+ B cell (IVW: OR [95 %]: 1.021 [1.011 to 1.031], p = 4.821E-05) and other 12 immune cells were associated with increased risk of MDD in MR, while HLA DR++ monocyte %leukocyte (IVW: OR [95 %]: 0.973 [0.948 to 0.998], p = 0.038), CD4 on Central Memory CD4+ T cell (IVW: OR [95 %]: 0.979 [0.963 to 0.995], p = 0.011) and other 13 immune cells were associated with decreased risk of MDD in MR. Additionally, CD33+ HLA DR+ Absolute Count (IVW: OR [95 %]: 1.022[1.007 to 1.036], p = 0.007), CD28+ CD45RA- CD8+ T cell %T cell (IVW: OR [95 %]: 1.024 [1.008 to 1.041], p = 0.004) and other 18 immune cells were associated with increased risk of BD in MR, while CD62L on CD62L+ myeloid Dendritic Cell (IVW: OR [95 %]: 0.926 [0.871 to 0.985], p = 0.014), IgD- CD27- B cell %lymphocyte (IVW: OR [95 %]: 0.918 [0.880 to 0.956], p = 4.654E-05) and other 13 immune cells were associated with decreased risk of BD in MR.

CONCLUSIONS

This MR study provides robust evidence supporting a causal relationship between immune cells and the susceptibility to MDD and BD, offering valuable insights for future clinical investigations. Experimental studies are also required to further examine causality, mechanisms, and treatment potential for these immune cells for MDD and BD.

Neuroinflammation, memory, and depression: new approaches to hippocampal neurogenesis

As one of most common and severe mental disorders, major depressive disorder (MDD) significantly increases the risks of premature death and other medical conditions for patients. Neuroinflammation is the abnormal immune response in the brain, and its correlation with MDD is receiving increasing attention. Neuroinflammation has been reported to be involved in MDD through distinct neurobiological mechanisms, among which the dysregulation of neurogenesis in the dentate gyrus (DG) of the hippocampus (HPC) is receiving increasing attention. The DG of the hippocampus is one of two niches for neurogenesis in the adult mammalian brain, and neurotrophic factors are fundamental regulators of this neurogenesis process. The reported cell types involved in mediating neuroinflammation include microglia, astrocytes, oligodendrocytes, meningeal leukocytes, and peripheral immune cells which selectively penetrate the blood-brain barrier and infiltrate into inflammatory regions. This review summarizes the functions of the hippocampus affected by neuroinflammation during MDD progression and the corresponding influences on the memory of MDD patients and model animals.

The relationship between coping self-efficacy and B cells in breast cancer patients

BACKGROUND

Breast cancer is the most common tumor among women throughout the world. Diagnosis and treatment of breast cancer are associated with stress and depression. Self-efficacy is one of the most important personal characteristics, studied in cancer, and is correlated with depression and immunity. The aim of the study is as follows: 1. Examining the correlation between coping self-efficacy with depression, DHEA levels, and immunity 2. Examining the correlation between depression and DHEA levels 3. Studying the effect of depression and DHEA levels on immunity 4. Examining the intermediate effect of DHEA levels on the correlation between coping self-efficacy and immunity METHODS: Thirty newly diagnosed breast cancer patients recruited from the Oncology Department, Kasr EL-Aini, Cairo University (ages 51.40 + 8.24 years) responded to two questionnaires: Coping Self-Efficacy Scale (CSES) and Patient Health Questionnaire-9 (PHQ-9); blood samples were collected to measure the phenotype of patients' cellular immunity and DHEA levels by flowcytometry and ELISA technique.

RESULTS

There was a significant negative correlation between CSES and PHQ-9, a significant positive correlation between PHQ-9 and B-cell count, and there is a significant negative correlation between CSES and B-cell count. The presence of DHEA has no mediatory role on correlation between CSES and B-cell count.

CONCLUSION

This paper presents a new model of psychoneuroimmunology by suggesting an effect of coping self-efficacy on immunity against breast cancer patients.

Targeting the Adaptive Immune System in Depression: Focus on T Helper 17 Cells

There is a vital need to understand mechanisms contributing to susceptibility to depression to improve treatments for the 11% of Americans who currently suffer from this debilitating disease. The adaptive immune system, comprising T and B cells, has emerged as a potential contributor to depression, as demonstrated in the context of lymphopenic mice. Overall, patients with depression have reduced circulating T and regulatory B cells, "immunosuppressed" T cells, and alterations in the relative abundance of T cell subtypes. T helper (Th) cells have the capacity to differentiate to various lineages depending on the cytokine environment, antigen stimulation, and costimulation. Regulatory T cells are decreased, and the Th1/Th2 ratio and the Th17 cells are increased in patients with depression. Evidence for changes in each Th lineage has been reported to some extent in patients with depression. However, the evidence is strongest for the association of depression with changes in Th17 cells. Th17 cells produce the inflammatory cytokine interleukin (IL)-17A, and the discovery of Th17 cell involvement in depression evolved from the well established link that IL-6, which is required for Th17 cell differentiation, contributes to the onset, and possibly maintenance, of depression. One intriguing action of Th17 cells is their participation in the gut-brain axis to mediate stress responses. Although the mechanisms of action of Th17 cells in depression remain unclear, neutralization of IL-17A by anti-IL-17A antibodies, blocking stress-induced production, or release of gut Th17 cells represent feasible therapeutic approaches and might provide a new avenue to improve depression symptoms. SIGNIFICANCE STATEMENT: Th17 cells appear as a promising therapeutic target for depression, for which efficacious therapeutic options are limited. The use of neutralizing antibodies targeting Th17 cells has provided encouraging results in depressed patients with comorbid autoimmune diseases.

New-onset depression after hip fracture surgery among older patients: Effects on associated clinical outcomes and what can we do?

BACKGROUND

Hip fracture in the elderly is a worldwide medical problem. New-onset depression after hip fracture has also received attention because of its increasing incidence and negative impact on recovery.

AIM

To provide a synthesis of the literature addressing two very important questions arising from postoperative hip fracture depression (PHFD) research: the risk factors and associated clinical outcomes of PHFD, and the optimal options for intervention in PHFD.

METHODS

We searched the PubMed, Web of Science, EMBASE, and PsycINFO databases for English papers published from 2000 to 2021.

RESULTS

Our results showed that PHFD may result in poor clinical outcomes, such as poor physical function and more medical support. In addition, the risk factors for PHFD were summarized, which made it possible to assess patients preoperatively. Moreover, our work preliminarily suggested that comprehensive care may be the optimal treatment option for PHFDs, while interdisciplinary intervention can also be clinically useful.

CONCLUSION

We suggest that clinicians should assess risk factors for PHFDs preoperatively, and future research should further validate current treatment methods in more countries and regions and explore more advanced solutions.

B-cells are abnormal in psychosocial stress and regulate meningeal myeloid cell activation

There is increasing interest in how immune cells, including those within the meninges at the blood-brain interface, influence brain function and mood disorders, but little data on humoral immunity in this context. Here, we show that in mice exposed to psychosocial stress, there is increased splenic B cell activation and secretion of the immunoregulatory cytokine interleukin (IL)-10. Meningeal B cells were prevalent in homeostasis but substantially decreased following stress, whereas Ly6Chi monocytes increased, and meningeal myeloid cells showed augmented expression of activation markers. Single-cell RNA sequencing of meningeal B cells demonstrated the induction of innate immune transcriptional programmes following stress, including genes encoding antimicrobial peptides that are known to alter myeloid cell activation. Cd19-/- mice, that have reduced B cells, showed baseline meningeal myeloid cell activation and decreased exploratory behaviour. Together, these data suggest that B cells may influence behaviour by regulating meningeal myeloid cell activation.

Influence of Stress and Depression on the Immune System in Patients Evaluated in an Anti-aging Unit

Background

There is compelling evidence pointing out that stress and depression produce a dramatic impact on human well-being mainly through impairing the regular function of the immune system and producing a low-chronic inflammation status that favors the occurrence of infections, metabolic diseases, and even cancer. The present work aims to evaluate the stress/depression levels of some patients treated in an antiaging unit and detect any potential relationship with their immune system status prior of the implementation of a physical/psychological program designed to prevent health deterioration.

Methods

We evaluated 48 patients (16 men and 32 women with a mean age of 55.11 ± 10.71 years) from middle-upper class from psychological and immunological points of view. In particular, we analyzed neutrophil chemotaxis and phagocytosis; lymphocyte chemotaxis and proliferation, and natural killer (NK) cell activity.

Results

Women showed more depressive symptoms than men. Chemotaxis levels of lymphocytes and neutrophils in women showed a significant reduction compared with those in men. We also found a strong negative correlation between depression and NK cell function. This correlation was also significant independently of gender.

Conclusion

We conclude that NK activity is affected at least by depression state, and we propose that a combined treatment consisting of cognitive behavioral therapy and physical activity programs might improve patient health deterioration.

Moderate physical activity associated with a higher naïve/memory T-cell ratio in healthy old individuals: potential role of IL15

INTRODUCTION

ageing is accompanied by impairments in immune responses due to remodelling of the immune system (immunesenescence). Additionally, a decline in habitual physical activity has been reported in older adults. We have recently published that specific features of immunesenescence, such as thymic involution and naïve/memory T-cell ratio, are prevented by maintenance of a high level of physical activity. This study compares immune ageing between sedentary and physically active older adults.

METHODS

a cross-sectional study recruited 211 healthy older adults (60-79 years) and assessed their physical activity levels using an actigraph. We compared T- and B-cell immune parameters between relatively sedentary (n = 25) taking 2,000-4,500 steps/day and more physically active older adults (n = 25) taking 10,500-15,000 steps/day.

RESULTS

we found a higher frequency of naïve CD4 (P = 0.01) and CD8 (P = 0.02) and a lower frequency of memory CD4 cells (P = 0.01) and CD8 (P = 0.04) T cells in the physically active group compared with the sedentary group. Elevated serum IL7 (P = 0.03) and IL15 (P = 0.003), cytokines that play an essential role in T-cell survival, were seen in the physically active group. Interestingly, a positive association was observed between IL15 levels and peripheral CD4 naïve T-cell frequency (P = 0.023).

DISCUSSION

we conclude that a moderate level of physical activity may be required to give a very broad suppression of immune ageing, though 10,500-15,000 steps/day has a beneficial effect on the naïve T-cell pool.

Altered B Cell Homeostasis in Patients with Major Depressive Disorder and Normalization of CD5 Surface Expression on Regulatory B Cells in Treatment Responders

Pro-inflammatory activity and cell-mediated immune responses have been widely observed in patients with major depressive disorder (MDD). Besides their well-known function as antibody-producers, B cells play a key role in inflammatory responses by secreting pro- and anti-inflammatory factors. However, homeostasis of specific B cell subsets has not been comprehensively investigated in MDD. In this study, we characterized circulating B cells of distinct developmental steps including transitional, naïve-mature, antigen-experienced switched, and non-switched memory cells, plasmablasts and regulatory B cells by multi-parameter flow cytometry. In a 6-weeks follow-up, circulating B cells were monitored in a small group of therapy responders and non-responders. Frequencies of naïve lgD⁺CD27^- B cells, but not lgD⁺CD27⁺ memory B cells, were reduced in severely depressed patients as compared to healthy donors (HD) or mildly to moderately depressed patients. Specifically, B cells with immune-regulatory capacities such as CD1d⁺CD5⁺ B cells and CD24⁺CD38^hi transitional B cells were reduced in MDD. Also Bm1-Bm5 classification in MDD revealed reduced Bm2' cells comprising germinal center founder cells as well as transitional B cells. We further found that reduced CD5 surface expression on transitional B cells was associated with severe depression and normalized exclusively in clinical responders. This study demonstrates a compromised peripheral B cell compartment in MDD with a reduction in B cells exhibiting a regulatory phenotype. Recovery of CD5 surface expression on transitional B cells in clinical response, a molecule involved in activation and down-regulation of B cell responses, further points towards a B cell-dependent process in the pathogenesis of MDD.

Increased IL-15 Production and Accumulation of Highly Differentiated CD8+ Effector/Memory T Cells in the Bone Marrow of Persons with Cytomegalovirus

Cytomegalovirus (CMV) has been described as a contributor to immunosenescence, thus exacerbating age-related diseases. In persons with latent CMV infection, the CD8⁺ T cell compartment is irreversibly changed, leading to the accumulation of highly differentiated virus-specific CD8⁺ T cells in the peripheral blood. The bone marrow (BM) has been shown to play a major role in the long-term survival of antigen-experienced T cells. Effector CD8⁺ T cells are preferentially maintained by the cytokine IL-15, the expression of which increases in old age. However, the impact of CMV on the phenotype of effector CD8⁺ T cells and on the production of T cell survival molecules in the BM is not yet known. We now show, using BM samples obtained from persons who underwent hip replacement surgery because of osteoarthrosis, that senescent CD8⁺ T_EMRA cells with a bright expression of CD45RA and a high responsiveness to IL-15 accumulate in the BM of CMV-infected persons. A negative correlation was found between CMV antibody (Ab) titers in the serum and the expression of CD28 and IL-7Rα in CD8⁺ [Formula: see text] cells. Increased IL-15 mRNA levels were observed in the BM of CMV⁺ compared to CMV^- persons, being particularly high in old seropositive individuals. In summary, our results indicate that a BM environment rich in IL-15 may play an important role in the maintenance of highly differentiated CD8⁺ T cells generated after CMV infection.