Major Depressive Disorder Enhances Th2 and Th17 Cytokines in Patients Suffering from Allergic Rhinitis and Asthma

Is Nasal Dysbiosis a Required Component for Neuroinflammation in Major Depressive Disorder?

Human microbiota is known to influence immune and cerebral responses by direct and/or indirect mechanisms, including hypothalamic-pituitary-adrenal axis signaling, activation of neural afferent circuits to the brain, and by altering the peripheral immune responses (cellular and humoral immune function, circulatory inflammatory cells, and the production of several inflammatory mediators, such as cytokines, chemokines, and reactive oxygen species). The inflammatory responses in the nasal mucosa (rhinitis) or paranasal sinuses (chronic rhinosinusitis) are dual conditions related with a greater risk for developing depression. In the nasal cavity, anatomic components of the olfactive function are in direct contact with the CNS through the olfactory receptors, neurons, and axons that end in the olfactory bulb and the entorhinal cortex. Local microbiome alterations (dysbiosis) are linked to transepithelial translocation of microorganisms and their metabolites, which disrupts the epithelial barrier and favors vascular permeability, increasing the levels of several inflammatory molecules (both cytokines and non-cytokine mediators: extracellular vesicles (exosomes) and neuropeptides), triggering local inflammation (rhinitis) and the spread of these components into the central nervous system (neuroinflammation). In this review, we discuss the role of microbiota-related immunity in conditions affecting the nasal mucosa (chronic rhinosinusitis and allergic rhinitis) and their relevance in major depressive disorders, focusing on the few mechanisms known to be involved and providing some hypothetical proposals on the pathophysiology of depression.

Systemic Inflammation in Asthma: What Are the Risks and Impacts Outside the Airway?

Airway inflammation in asthma has been well recognized for several decades, with general agreement on its role in asthma pathogenesis, symptoms, propensity toward exacerbation, and decline in lung function. This has led to universal recommendation in asthma management guidelines to incorporate the use of inhaled corticosteroid as an anti-inflammatory therapy for all patients with persistent asthma symptoms. However, there has been limited attention paid to the presence and potential impact of systemic inflammation in asthma. Accumulating evidence from epidemiological observations and cohort studies points to a host of downstream organ dysfunction in asthma especially among patients with longstanding or more severe disease, frequent exacerbations, and underlying risk factors for organ dysfunction. Most studies to date have focused on cognitive impairment, depression/anxiety, metabolic syndrome, and cardiovascular abnormalities. In this review, we summarize some of the evidence demonstrating these abnormalities and highlight the proposed mechanisms and potential benefits of treatment in limiting these extrapulmonary abnormalities in patients with asthma. The goal of this commentary is to raise awareness of the importance of recognizing potential extrapulmonary conditions associated with systemic inflammation of asthma. This area of treatment of patients with asthma is a large unmet need.

P2X7 receptor of olfactory bulb microglia plays a pathogenic role in stress-related depression in mice with allergic rhinitis

The aim of this study was to explore the role and mechanism of the olfactory bulb (OB) microglial P2X7 receptor (P2X7R) in allergic rhinitis (AR)-related depression, with the objective of identifying a potential clinical target. An AR mouse model was induced using ovalbumin (OVA), while chronic stress was employed to induce depression. The study used P2X7R-specific antagonists and OB microglia-specific P2X7R knockdown mice as crucial tools. The results showed that mice in the OVA + stress group exhibited more pronounced depressive-like phenotypes. Furthermore, there was an observed increase in microglial activation in the OB, followed by a rise in the level of inflammation. The pharmacological inhibition of P2X7R significantly mitigated the depression-like phenotype and the OB inflammatory response in OVA + stress mice. Notably, the specific knockdown of microglial P2X7R in the OB resulted in a similar effect, possibly linked to the regulation of IL-1β via the "ATP-P2X7R-Caspase 1" axis. These findings collectively demonstrate that microglial P2X7R in the OB acts as a direct effector molecule in AR-related depression, and its inhibition may offer a novel strategy for clinical prevention and treatment.

Th17 Cells, Glucocorticoid Resistance, and Depression

Depression is a severe mental disorder that disrupts mood and social behavior and is one of the most common neuropsychological symptoms of other somatic diseases. During the study of the disease, a number of theories were put forward (monoamine, inflammatory, vascular theories, etc.), but none of those theories fully explain the pathogenesis of the disease. Steroid resistance is a characteristic feature of depression and can affect not only brain cells but also immune cells. T-helper cells 17 type (Th17) are known for their resistance to the inhibitory effects of glucocorticoids. Unlike the inhibitory effect on other subpopulations of T-helper cells, glucocorticoids can enhance the differentiation of Th17 lymphocytes, their migration to the inflammation, and the production of IL-17A, IL-21, and IL-23 in GC-resistant disease. According to the latest data, in depression, especially the treatment-resistant type, the number of Th17 cells in the blood and the production of IL-17A is increased, which correlates with the severity of the disease. However, there is still a significant gap in knowledge regarding the exact mechanisms by which Th17 cells can influence neuroinflammation in depression. In this review, we discuss the mutual effect of glucocorticoid resistance and Th17 lymphocytes on the pathogenesis of depression.

Relationship Between the Response to Antibody Therapy and Symptoms of Depression and Anxiety Disorders in Patients with Severe Asthma

Purpose

Asthma is associated with a high prevalence of psychopathological disorders, especially depressive disorders or anxiety. In patients with uncontrolled severe asthma, monoclonal antibody (mAb)-therapy positively influenced control of mental disorders. Therefore, we evaluated the impact of antibody therapy on the burden of these mental diseases depending on responder status.

Patients and Methods

Data were collected retrospectively in patients with uncontrolled severe asthma (n = 82) prior to mAb-therapy ("baseline") (omalizumab, dupilumab, benralizumab or mepolizumab). Symptoms of Major Depressive Disorder (MDD) or General Anxiety Disorder (GAD) were detected at baseline using the Hospital Anxiety and Depression Scale (HADS), as well as general sociodemographic data and lung function parameters. At 6-month (±3 month) follow-up, the burden of psychopathological symptoms under mAb-therapy was assessed using the Patient Health Questionnaire-2 (PHQ-2) and Generalized Anxiety Disorder Scale-2 (GAD-2). Response status was classified using the Biologics Asthma Response Score (BARS), assessing exacerbations, oral corticosteroid usage and asthma control test (ACT) score. Predictors for non-response to mAb-therapy were identified using linear regression analysis.

Results

Patients with severe asthma suffered from symptoms of MDD/GAD more often compared to the general population, with a higher prevalence among mAb therapy non-responders. mAb-responders exhibited a declining burden of MDD, better quality of life (QoL), less exacerbations, better lung function and better disease control compared to non-responders. A history of symptoms of depression was identified as a predictor for non-response to mAb-therapy.

Conclusion

Asthma symptoms and psychological problems are linked and more prevalent in our cohort of severe asthma patients than in the general population. Patients with signs of MDD/GAD before mAb-therapy show less mAb therapy response suggesting a negative impact of prior psychological problems on treatment response. In some patients, the score on MDD/GAD was caused by severe asthma - here symptoms decreased after effective treatment.

Brain response in allergic rhinitis: Profile and proposal

In addition to typical nasal symptoms, patients with allergic rhinitis (AR) will further lead to symptoms related to brain function such as hyposmia, anxiety, depression, cognitive impairment, memory loss, etc., which seriously affect the quality of life of patients and bring a heavy burden to the patient's family and society. Some scholars have speculated that there may be potential "nose-brain communication" mechanism in AR that rely on neuro-immunity. This mechanism plays an important role in AR-associated brain response process. However, no study has directly demonstrated which neural circuits will change in the connection between the nose and brain during the onset of AR, and the mechanism which underlines this question is also lack. Focusing on the topic of "nose-brain communication", this paper systematically summarizes the latest research progress between AR and related brain responses and discusses the mechanism of AR-related neurological phenotypes. Hope new diagnostic and therapeutic targets to ameliorate the brain function-related symptoms and improve the quality of life of AR patients will be developed.

Evaluating the effect of antidepressants on the relationship between depression and asthma

BACKGROUND

It is unclear if depression is associated with impaired lung function in subjects with asthma, while few studies evaluated the effect of antidepressants on the relationship between depression and asthma. We designed this study to investigate if subjects with concomitant asthma and depression not taking antidepressants have worse asthma outcomes compared to asthmatic subjects without depression, and to evaluate whether antidepressants modify this association.

METHODS

This is a cross-sectional study. We included non-smokers with asthma, 18 years old or above. Study subjects attended an appointment with a chest physician, answered study questionnaires and underwent a spirometry test. We performed crude and adjusted binary logistic regression analyses.

RESULTS

We enrolled 309 subjects with asthma, of whom 48 with depression taking antidepressants, 52 with depression not taking antidepressants, and 209 without depression (control group). Asthmatic subjects with depression who had not used antidepressants before enrollment were more likely to have uncontrolled symptoms of asthma [adjusted OR 3.10, 95CI (1.56-6.15)] and airway obstruction [adjusted OR 2.41, 95CI (1.24-4.69)] compared to the control group. Subjects who had used antidepressants had higher odds of uncontrolled symptoms of asthma [adjusted OR 3.02, 95CI (1,50-6.07)], but similar odds of airway obstruction [adjusted OR 1.24, 95CI (0.87-1.77)] compared to the control group.

CONCLUSIONS

Non-treated depression is associated with airway obstruction in subjects with asthma, but antidepressants modify this association. Thus, we recommend regular screening of depression in subjects with asthma, and prescription of antidepressants whenever depression symptoms justify pharmacological therapy.

Plasma levels of interleukin-8 and response to paroxetine in patients with major depressive disorder

OBJECTIVES

Immune dysregulation plays a key role in major depressive disorder (MDD). However, little is known about the complicated involvement of various interleukins in MDD. This study was performed to investigate the correlation between plasma interleukin-8 (IL-8) levels and treatment outcome of paroxetine (a selective serotonin reuptake inhibitor) in patients with MDD.

METHODS

A total of 115 hospitalized patients (36 males and 79 females), aged from 18 to 72 years, were enrolled. Plasma levels of IL-8 were measured before treatment initiation (baseline) and at 8 weeks after oral paroxetine treatment. Efficacy of paroxetine was evaluated by use of the Hamilton Depression Rating Scale (HAMD-17). Baseline IL-8 levels were compared between responders and non-responders to paroxetine treatment.

RESULTS

Plasma IL-8 levels decreased significantly after an 8-week antidepressant treatment in responders, in association with a dramatic decrease in HAMD-17 scores. In non-responders, plasma IL-8 levels did not change significantly at 8 weeks after antidepressant treatment. Baseline plasma IL-8 levels were found to be significantly lower in responders than in non-responders, showing a correlation between IL-8 and antidepressant response to paroxetine.

CONCLUSIONS

These results indicate that plasma IL-8 levels were related to treatment outcome of paroxetine, and therefore suggest that IL-8 could be a promising predicator of treatment response in individual patients with MDD.

Bi-directional associations between depressive symptoms and asthma in middle-aged and elderly adults in China

BACKGROUND

There is currently no evidence of an association between depressive symptoms and asthma among older adults in China. We explored the bi-directional associations between depressive symptoms and asthma, and their changes in middle-aged and elderly adults from a national cohort.

METHODS

A longitudinal cohort study was conducted with a total of 17,708 individuals from 150 urban communities and 450 rural villages in 28 provinces in China.

RESULTS

After making exclusions, 11,492 and 8604 participants were included for incident asthma and incident depressive symptoms analysis, respectively. The incidence density was 4.46 and 10.24 for every 1000 person-years, respectively. Baseline depressive symptoms were associated with a higher risk of incident asthma (Hazard ratio [HR] = 1.60, 95 % confidence interval [CI]: 1.27, 2.02). Decreased depressive symptoms during baseline or follow-ups or both baseline and follow-ups were associated with a lower risk of incident asthma (P_{for trend} < 0.0001). Every 1-score increment of CES-D score was associated with a 4 % increase in asthma, with a non-linear association (P = 0.04) between CES-D score (break point = 7) and asthma. Asthma status increased the risk of participants with severe depressive symptoms (HR = 1.51, 95 % CI: 1.19, 1.92), especially in males (P_{for interaction} = 0.02).

LIMITATIONS

Depressive symptoms and asthma were assessed by validated questionnaires instead of clinical diagnosis.

CONCLUSIONS

Bi-directional associations between asthma and depressive symptoms do exist. Effective measures should be taken to reduce depressive symptoms and the risk of incident asthma in middle aged and elderly adults in China.

Chronic allergic lung inflammation negatively influences neurobehavioral outcomes in mice

BACKGROUND

Asthma is a major public health problem worldwide. Emerging data from epidemiological studies show that allergies and allergic diseases may be linked to anxiety, depression and cognitive decline. However, little is known about the effect of asthma, an allergic lung inflammation, on cognitive decline/behavioral changes. Therefore, we investigated the hypothesis that allergic lung inflammation causes inflammation in the brain and leads to neurobehavioral changes in mice.

METHODS

Wild-type C57BL/6J female mice were sensitized with nasal house dust mite (HDM) antigen or control PBS for 6 weeks to induce chronic allergic lung inflammation. A series of neurocognitive tests for anxiety and/or depression were performed before and after the intranasal HDM administration. After the behavior tests, tissues were harvested to measure inflammation in the lungs and the brains.

RESULTS

HDM-treated mice exhibited significantly increased immobility times during tail suspension tests and significantly decreased sucrose preference compared with PBS controls, suggesting a more depressed and anhedonia phenotype. Spatial memory impairment was also observed in HDM-treated mice when assessed by the Y-maze novel arm tests. Development of lung inflammation after 6 weeks of HDM administration was confirmed by histology, bronchoalveolar lavage (BAL) cell count and lung cytokine measurements. Serum pro-inflammatory cytokines and Th2-related cytokines levels were elevated in HDM-sensitized mice. In the brain, the chemokine fractalkine was increased in the HDM group. The c-Fos protein, a marker for neuronal activity, Glial Fibrillary Acidic Protein (GFAP) and chymase, a serine protease from mast cells, were increased in the brains from mice in HDM group. Chymase expression in the brain was negatively correlated with the results of sucrose preference rate in individual mice.

CONCLUSIONS

6 weeks of intranasal HDM administration in mice to mimic the chronic status of lung inflammation in asthma, caused significant inflammatory histological changes in the lungs, and several behavioral changes consistent with depression and altered spatial memory. Chymase and c-Fos proteins were increased in the brain from HDM-treated mice, suggesting links between lung inflammation and brain mast cell activation, which could be responsible for depression-like behavior.

Emerging Roles of T Helper Cells in Non-Infectious Neuroinflammation: Savior or Sinner

CD4⁺ T cells, also known as T helper (Th) cells, contribute to the adaptive immunity both in the periphery and in the central nervous system (CNS). At least seven subsets of Th cells along with their signature cytokines have been identified nowadays. Neuroinflammation denotes the brain’s immune response to inflammatory conditions. In recent years, various CNS disorders have been related to the dysregulation of adaptive immunity, especially the process concerning Th cells and their cytokines. However, as the functions of Th cells are being discovered, it’s also found that their roles in different neuroinflammatory conditions, or even the participation of a specific Th subset in one CNS disorder may differ, and sometimes contrast. Based on those recent and contradictory evidence, the conflicting roles of Th cells in multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, epilepsy, traumatic brain injury as well as some typical mental disorders will be reviewed herein. Research progress, limitations and novel approaches concerning different neuroinflammatory conditions will also be mentioned and compared.

Major depression favors the expansion of Th17-like cells and decrease the proportion of CD39+Treg cell subsets in response to myelin antigen in multiple sclerosis patients

BACKGROUND

Mood disorders have been associated with risk of clinical relapses in multiple sclerosis (MS), a demyelinating disease mediated by myelin-specific T cells.

OBJECTIVES

We aimed to investigate the impact of major depressive disorder (MDD) and cytokine profile of T-cells in relapsing remitting MS patients.

METHODS

For our study, plasma and PBMC were obtained from 60 MS patients (30 with lifetime MDD) in remission phase. The PBMC cultures were stimulated with anti-CD3/anti-CD28 beads or myelin basic protein (MBP), and effector and regulatory T cell phenotypes were determined by flow cytometry. The cytokine levels, both in the plasma or in the supernatants collected from PBMC cultures, were quantified by Luminex. In some experiments, the effect of serotonin (5-HT) was investigated.

RESULTS

Here, higher Th17-related cytokine levels in response to anti-CD3/anti-CD28 and MBP were quantified in the plasma and PBMC cultures of the MS/MDD group in comparison with MS patients. Further, elevated frequency of CD4+ and CD8+ T cells capable of producing IL-17, IL-22 and GM-CSF was observed in depressed patients. Interestingly, the percentage of myelin-specific IFN-γ+IL-17+ and IFN-γ+GM-CSF+ CD4+ T cells directly correlated with neurological disabilities. In contrast, the occurrence of MDD reduced the proportion of MBP-specific CD39+Tregs subsets. Notably, the severity of both neurological disorder and depressive symptoms inversely correlated with these Tregs. Finally, the addition of 5-HT downregulated the release of Th17-related cytokines in response to anti-CD3/anti-CD28 and myelin antigen.

CONCLUSIONS

In summary, our findings suggested that recurrent major depression, by favoring imbalances of effector Th17 and Treg cell subsets, contributes to MS severity.

Crosstalk between ILC2s and Th2 CD4+ T Cells in Lung Disease

Cytokine secretion, such as interleukin-4 (IL-4), IL-5, IL-9, IL-13, and amphiregulin (Areg), by type 2 innate lymphoid cells (ILC2s) is indispensable for homeostasis, remodeling/repairing tissue structure, inflammation, and tumor immunity. Often viewed as the innate cell surrogate of T helper type 2 (Th2) cells, ILC2s not only secrete the same type 2 cytokines, but are also inextricably related to CD4⁺T cells in terms of cell origin and regulatory factors, bridging between innate and adaptive immunity. ILC2s interact with CD4⁺T cells to play a leading role in a variety of diseases through secretory factors. Here, we review the latest progress on ILC2s and CD4⁺T cells in the lung, the close relationship between the two, and their relevance in the lung disease and immunity. This literature review aids future research in pulmonary type 2 immune diseases and guides innovative treatment approaches for these diseases.

Relationship between allergic diseases and mental disorders in women: A systematic review and meta-analysis

BACKGROUND

The relationship between allergic diseases (AD) and mental disorders (MD) in women has not been fully systematically evaluated. We aimed at validating this correlation.

METHODS

The relevant cohort and case-control studies from the establishment of the database to February 18, 2022 in PubMed, Embase, and Cochrane library were searched by computer. The researchers conducted the quality evaluation of the included articles by reviewing and discussing with reference to relevant standards, and conducted the analysis of the correlation between female patients with AD and MD by using Review Manager 5.4.

RESULTS

Six observational studies from 2631 studies (n = 1160858 women) were assessed as medium and high-quality studies. The meta-analysis demonstrated that AD was correlated with MD in female patients (OR = 1.21, 95%CI: 1.14-1.29), including asthma (OR = 1.16, 95%CI: 1.11-1.22), allergic rhinitis (OR = 1.31, 95%CI: 1.06-1.63), and atopic dermatitis in women (OR = 1.37, 95%CI: 1.24-1.50) were associated with MD. At the same time, subgroup analysis was performed according to region, study design, criteria of AD and MD, and the results demonstrated that both AD and MD were correlated in these different conditions.

CONCLUSION

Allergic diseases in female patients do have an association with mental disorders.

SYSTEMATIC REVIEW REGISTRATION

[https://www.crd.york.ac.uk/PROSPERO/], identifier [CRD42022311146].

Allergic Rhinitis and Depression: Profile and Proposal

In addition to nasal symptoms, patients with allergic rhinitis (AR) often experience mental and psychological disorders such as depression. Depression not only makes the treatment of AR more difficult and expensive but also poses a serious impact on the patients' daily activities and quality of life, thus bringing additional burden to the families and the society. Here we systematically review the recent research advances in the correlation between AR and depression, analyze the possible causes and mechanisms of depression in AR, summarize the current diagnosis and treatment strategies, and provide our insights into the AR-related depression; in addition, we introduce briefly the basic research status on AR-related depression. We hope that this review article will provide evidence for future studies.