Allergic rhinitis induces anxiety-like behavior and altered social interaction in rodents

The olfactory bulb: A neuroendocrine spotlight on feeding and metabolism

Olfaction is the most ancient sense and is needed for food-seeking, danger protection, mating and survival. It is often the first sensory modality to perceive changes in the external environment, before sight, taste or sound. Odour molecules activate olfactory sensory neurons that reside on the olfactory epithelium in the nasal cavity, which transmits this odour-specific information to the olfactory bulb (OB), where it is relayed to higher brain regions involved in olfactory perception and behaviour. Besides odour processing, recent studies suggest that the OB extends its function into the regulation of food intake and energy balance. Furthermore, numerous hormone receptors associated with appetite and metabolism are expressed within the OB, suggesting a neuroendocrine role outside the hypothalamus. Olfactory cues are important to promote food preparatory behaviours and consumption, such as enhancing appetite and salivation. In addition, altered metabolism or energy state (fasting, satiety and overnutrition) can change olfactory processing and perception. Similarly, various animal models and human pathologies indicate a strong link between olfactory impairment and metabolic dysfunction. Therefore, understanding the nature of this reciprocal relationship is critical to understand how olfactory or metabolic disorders arise. This present review elaborates on the connection between olfaction, feeding behaviour and metabolism and will shed light on the neuroendocrine role of the OB as an interface between the external and internal environments. Elucidating the specific mechanisms by which olfactory signals are integrated and translated into metabolic responses holds promise for the development of targeted therapeutic strategies and interventions aimed at modulating appetite and promoting metabolic health.

AllergoOncology: Biomarkers and refined classification for research in the allergy and glioma nexus-A joint EAACI-EANO position paper

Epidemiological studies have explored the relationship between allergic diseases and cancer risk or prognosis in AllergoOncology. Some studies suggest an inverse association, but uncertainties remain, including in IgE-mediated diseases and glioma. Allergic disease stems from a Th2-biased immune response to allergens in predisposed atopic individuals. Allergic disorders vary in phenotype, genotype and endotype, affecting their pathophysiology. Beyond clinical manifestation and commonly used clinical markers, there is ongoing research to identify novel biomarkers for allergy diagnosis, monitoring, severity assessment and treatment. Gliomas, the most common and diverse brain tumours, have in parallel undergone changes in classification over time, with specific molecular biomarkers defining glioma subtypes. Gliomas exhibit a complex tumour-immune interphase and distinct immune microenvironment features. Immunotherapy and targeted therapy hold promise for primary brain tumour treatment, but require more specific and effective approaches. Animal studies indicate allergic airway inflammation may delay glioma progression. This collaborative European Academy of Allergy and Clinical Immunology (EAACI) and European Association of Neuro-Oncology (EANO) Position Paper summarizes recent advances and emerging biomarkers for refined allergy and adult-type diffuse glioma classification to inform future epidemiological and clinical studies. Future research is needed to enhance our understanding of immune-glioma interactions to ultimately improve patient prognosis and survival.

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.

Neuroimmune communication in allergic rhinitis

The prevalence rate of allergic rhinitis (AR) is high worldwide. The inhalation of allergens induces AR, which is an immunoglobulin E-mediated and type 2 inflammation-driven disease. Recently, the role of neuroimmune communication in AR pathogenesis has piqued the interest of the scientific community. Various neuropeptides, such as substance P (SP), vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), nerve growth factor (NGF), and neuromedin U (NMU), released via "axon reflexes" or "central sensitization" exert regulatory effects on immune cells to elicit "neurogenic inflammation," which contributes to nasal hyperresponsiveness (NHR) in AR. Additionally, neuropeptides can be produced in immune cells. The frequent colocalization of immune and neuronal cells at certain anatomical regions promotes the establishment of neuroimmune cell units, such as nerve-mast cells, nerve-type 2 innate lymphoid cells (ILC2s), nerve-eosinophils and nerve-basophils units. Receptors expressed both on immune cells and neurons, such as TRPV1, TRPA1, and Mas-related G protein-coupled receptor X2 (MRGPRX2) mediate AR pathogenesis. This review focused on elucidating the mechanisms underlying neuroimmune communication in AR.

Brain structural and functional alterations related to anxiety in allergic asthma

Psychiatric disorders are common in patients with allergic asthma, and they can have a significant impact on their quality of life and disease control. Recent studies have suggested that there may be potential immune-brain communication mechanisms in asthma, which can activate inflammatory responses in different brain areas, leading to structural and functional alterations and behavioral changes. However, the precise mechanisms underlying these alterations remain unclear. In this paper, we comprehensively review the relevant research on asthma-induced brain structural and functional alterations that lead to the initiation and promotion of anxiety. We summarize the possible pathways for peripheral inflammation to affect the brain's structure and function. Our review highlights the importance of addressing neuropsychiatric disorders in the clinical guidelines of asthma, to improve the quality of life of these patients. We suggest that a better understanding of the mechanisms underlying psychiatric comorbidities in asthma could lead to the development of more effective treatments for these patients.

Efficacy of catgut embedding in Baihui (GV20) and Feishu (BL13) and Pishu (BL20) on lung tissue, brain tissue and blood related indexes in rats with allergic rhinitis of lung deficiency type

OBJECTIVE

To investigate the effects of acupoint catgut embedding for 3 weeks on lung tissue, blood immunoglobulin E (IgE) and interleutin-4 (IL-4), brain tissue microglia x-42 (OX-42) and toll-like receptor-2 (TLR-2) in rats with allergic rhinitis of lung deficiency type.

METHODS

Forty-five female Sprague-Dawley rats were randomly divided for two times. The first time, they were randomly divided into model group and blank group (Group C) according to 2:1, and the second time, the model group were randomly divided into model control group (Group B) and intervention treatment group (Group A) according to 1:1. 15 in each group. For Group A and Group B, the lung deficiency model was made by "sulfur-moxa fumigation", and then the allergic rhinitis model was established by "ovalbumin (OVA) sensitization". Then catgut embedding was performed at acupoints in Group A and not in Group B. After 3 weeks, collect lung tissue samples for hematoxylin-eosin staining, then take blood to observe the concentration of IgE and IL-4, and finally take brain tissue to observe the results of OX-42 and TLR-2.

RESULTS

IgE level (μg/mL) was (3.11 ± 0.20) in the Group A, (4.19 ± 0.44) in the Group B, and (2.29 ± 0.30) in the Group C (all < 0.001). IL-4 level (pg/mL) was (14.2 ± 0.7) in the Group A, (18.6 ± 2.4) in the Group B, and (11.4 ± 1.2) for the Group C (all < 0.001). The mean OD for OX-42 is (0.1728 ± 0.0016) in the Group A, (0.1810 ± 0.0046) in the Group B and (0.1674 ± 0.0025) in the Group C (all < 0.001).

CONCLUSION

Although 3 weeks of acupoint catgut embedding already showed obvious efficacy on rats with allergic rhinitis, the allergic reaction in the body still continued. To achieve further treatment, prolonging the catgut embedding time is necessary.

Altered Fear Behavior in Aeroallergen House Dust Mite Exposed C57Bl/6 Mice: A Model of Th2-skewed Airway Inflammation

There is a growing interest for studying the impact of chronic inflammation, particularly lung inflammation, on the brain and behavior. This includes asthma, a chronic inflammatory condition, that has been associated with psychiatric conditions such as posttraumatic stress disorder (PTSD). Although asthma is driven by elevated production of Th2 cytokines (IL-4, IL-5 and IL-13), which drive asthma symptomology, recent work demonstrates that concomitant Th1 or Th17 cytokine production can worsen asthma severity. We previously demonstrated a detrimental link between PTSD-relevant fear behavior and allergen-induced lung inflammation associated with a mixed Th2/Th17-inflammatory profile in mice. However, the behavioral effects of Th2-skewed airway inflammation, typical to mild/moderate asthma, are unknown. Therefore, we investigated fear conditioning/extinction in allergen house dust mite (HDM)-exposed C57Bl/6 mice, a model of Th2-skewed allergic asthma. Behaviors relevant to panic, anxiety, and depression were also assessed. Furthermore, we investigated the accumulation of Th2/Th17-cytokine-expressing cells in lung and brain, and the neuronal activation marker, ΔFosB, in fear regulatory brain areas. HDM-exposed mice elicited lower freezing during fear extinction with no effects on acquisition and conditioned fear. No HDM effect on panic, anxiety or depression-relevant behaviors was observed. While HDM evoked a Th2-skewed immune response in lung tissue, no significant alterations in brain Th cell subsets were observed. Significantly reduced ΔFosB+ cells in the basolateral amygdala of HDM mice were observed post extinction. Our data indicate that allergen-driven Th2-skewed responses may induce fear extinction promoting effects, highlighting beneficial interactions of Th2-associated immune mediators with fear regulatory circuits.

Brain response in asthma: the role of "lung-brain" axis mediated by neuroimmune crosstalk

In addition to typical respiratory symptoms, patients with asthma are frequently accompanied by cognitive decline, mood disorders (anxiety and depression), sleep disorders, olfactory disorders, and other brain response manifestations, all of which worsen asthma symptoms, form a vicious cycle, and exacerbate the burden on families and society. Therefore, studying the mechanism of neurological symptoms in patients with asthma is necessary to identify the appropriate preventative and therapeutic measures. In order to provide a comprehensive reference for related research, we compiled the pertinent literature, systematically summarized the latest research progress of asthma and its brain response, and attempted to reveal the possible "lung-brain" crosstalk mechanism and treatment methods at the onset of asthma, which will promote more related research to provide asthmatic patients with neurological symptoms new hope.

[Neuroimmunology of allergic rhinitis part 2 : Interactions of neurons and immune cells and neuroimmunological units]

Allergic rhinitis is an IgE-mediated, type‑2 inflammatory disease. neuropeptides are released by neurons and interact with immune cells. Via colocalization, neuroimmune cell units such as nerve-mast cell units, nerve-type 2 innate lymphoid cell (ILC2) units, nerve-eosinophil units, and nerve-basophil units are formed. Markedly elevated tryptase levels were found in nasal lavage fluid and were strongly associated with neuropeptide levels. A close anatomical connection allows bidirectional communication between immune and neuronal cells. Transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin repeat 1 (TRPA1) are critically involved in immunological reactions in the setting of allergic rhinitis. Neuroimmunological communication plays an important role in the inflammatory process, so that allergic rhinitis can no longer be considered a purely immunological disease, but rather a combined neuroimmunological disease.

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.

Structural, functional and behavioral impact of allergic rhinitis on olfactory pathway and prefrontal cortex

BACKGROUND

Allergic rhinitis (AR) has been identified as a cause of olfactory dysfunction. Beyond the classic symptoms, AR has been associated with altered sleep patterns, a decline in cognitive performance and higher likelihood of depression and anxiety. The olfactory pathway has been postulated to be a possible link between nasal inflammation and central nervous system (CNS) modifications. Thus, we aimed to investigate the structural, functional and behavioral changes in the olfactory pathway and related areas in an animal model of AR.

METHODS

AR was induced in adult Wistar rats by ovalbumin sensitization and challenge. Following olfactory and behavioral tests we investigated the synaptic structure of the olfactory bulb (OB), anterior olfactory nuclei (AON), piriform cortex and prefrontal cortex (PFC), by immunofluorescence detection of synaptophysin (Syn) and glutamatergic, GABAergic and dopaminergic neuronal markers.

RESULTS

We detected a significant decrease in Syn in the glomerular layer (GL) of OB and in the PFC of the AR group. Additionally, the optical density of GAD67 and VGLUT2 was reduced in the OB, AON and PFC, compared to controls. The behavioral tests demonstrated olfactory dysfunction and reduced male aggressiveness in AR rats, but we did not find any difference in the cognition and anxiety-like behavior.

CONCLUSIONS

We confirmed olfactory dysfunction in a rat model of AR and we identified modifications in synaptic activity by reduction of Syn optical density in the GL of the OB and in the PFC. This was accompanied by structural changes in glutamatergic and GABAergic activity in essential components of the olfactory pathway and PFC.

Parasitic infections as potential risk factors for attention deficit hyperactivity disorder (ADHD) in children

Attention deficit hyperactivity disorder (ADHD) represents a mysterious neuropsychiatric alarming concern due to indefinite etiopathogenesis among children. Notably, the studies which investigated the correlation between ADHD and parasitic infections are insufficient. Therefore, this research aimed to assess the correlation between ADHD and some tissue dwelling and intestinal parasitic infections in children. The study was conducted on 200 children, including 100 children suffering from ADHD (Group I) and 100 healthy children as a control group (Group II). All caregivers fulfilled predesigned sociodemographic form and Conners parent rating scale (CPRS-48) questionnaire. Blood samples were collected to determine hemoglobin level as well as relative eosinophilic count. The presence of anti-Toxoplasma IgG and anti-Toxocara IgG in serum by Enzyme-Linked Immunosorbent Assay (ELISA) was further investigated. Also, micronutrients as zinc, iron, and copper levels were measured. Schistosoma antigen was investigated in urine samples. Stool samples were subjected to direct wet smear, concentration technique and modified Ziehl-Neelsen (MZN) staining for coccidian parasites detection. Cryptosporidium parvum, Giardia lamblia and Entamoeba histolytica antigens were investigated in stool samples. Group I expressed more liability to sociodemographic risk factors, decreased levels of Hb, iron, zinc, and copper with statistically significant difference (P < 0.001). Comparison between Group I and Group II regarding the detected parasitic infections exhibited statistically significant difference except Schistosoma antigen positivity which expressed no statistical significance. The present study concluded that the parasitic infections with their consequences are potential risk factors in children with ADHD indicating that their early diagnosis and treatment may help in ADHD prevention.

Olfactory impairment in psychiatric disorders: Does nasal inflammation impact disease psychophysiology?

Olfactory impairments contribute to the psychopathology of mental illnesses such as schizophrenia and depression. Recent neuroscience research has shed light on the previously underappreciated olfactory neural circuits involved in regulation of higher brain functions. Although environmental factors such as air pollutants and respiratory viral infections are known to contribute to the risk for psychiatric disorders, the role of nasal inflammation in neurobehavioral outcomes and disease pathophysiology remains poorly understood. Here, we will first provide an overview of published findings on the impact of nasal inflammation in the olfactory system. We will then summarize clinical studies on olfactory impairments in schizophrenia and depression, followed by preclinical evidence on the neurobehavioral outcomes produced by olfactory dysfunction. Lastly, we will discuss the potential impact of nasal inflammation on brain development and function, as well as how we can address the role of nasal inflammation in the pathophysiological mechanisms underlying psychiatric disorders. Considering the current outbreak of Coronavirus Disease 2019 (COVID-19), which often causes nasal inflammation and serious adverse effects for olfactory function that might result in long-lasting neuropsychiatric sequelae, this line of research is particularly critical to understanding of the potential significance of nasal inflammation in the pathophysiology of psychiatric disorders.

Infiltration of peripheral immune cells into the olfactory bulb in a mouse model of acute nasal inflammation

Chronic nasal inflammation induces robust olfactory bulb (OB) atrophy in mice. Here we examined initial events that occur in the OB after bilateral intranasal administration of lipopolysaccharide, focusing on the olfactory nerve fibers and meninges. We analyzed the time course of OB and meninges inflammation using histological and biochemical approaches. Within 12 h, we observed increased chemokine expression and transient infiltration of peripheral immune cells into the OB, resulting in the development of pro-inflammatory status in the OB. Meningeal immunity was activated. Resident microglia produced anti-inflammatory cytokines within 24 h. These could be the initial events that lead to OB atrophy.

ACC-BLA functional connectivity disruption in allergic inflammation is associated with anxiety

Allergic asthma is a chronic inflammatory respiratory disease. Psychiatric disorders, including anxiety are associated with poorer treatment response and disease control in asthmatic patients. To date, there is no experimental evidence describing the role of peripheral inflammation on the oscillatory activities in the anterior cingulate cortex (ACC) and basolateral amygdala (BLA), two major brain structures modulating anxiety. In the present work we evaluated lung and brain inflammatory responses, anxiety-like behavior, in association with oscillatory features of the ACC-BLA circuit in an animal model of allergic inflammation. Our data showed that allergic inflammation induced anxiety-like behavior and reactivation of microglia and astrocytes in ACC and BLA. Allergic inflammation also enhanced neuronal activities and functional connectivity of the ACC-BLA circuit which were correlated with the level of anxiety. Together, we suggest that disruption in the dynamic oscillatory activities of the ACC-BLA circuit, maybe due to regional inflammation, is an underlying mechanism of allergic asthma-induced anxiety-like behavior. Our findings could pave the way for better understanding the neuro-pathophysiology of the psychiatric disorders observed in asthmatic patients, possibly leading to develop novel treatment strategies.

Asthma, allergy and vitamin E: Current and future perspectives

Asthma and allergic disease result from interactions of environmental exposures and genetics. Vitamin E is one environmental factor that can modify development of allergy early in life and modify responses to allergen after allergen sensitization. Seemingly varied outcomes from vitamin E are consistent with the differential functions of the isoforms of vitamin E. Mechanistic studies demonstrate that the vitamin E isoforms α-tocopherol and γ-tocopherol have opposite functions in regulation of allergic inflammation and development of allergic disease, with α-tocopherol having anti-inflammatory functions and γ-tocopherol having pro-inflammatory functions in allergy and asthma. Moreover, global differences in prevalence of asthma by country may be a result, at least in part, of differences in consumption of these two isoforms of tocopherols. It is critical in clinical and animal studies that measurements of the isoforms of tocopherols be determined in vehicles for the treatments, and in the plasma and/or tissues before and after intervention. As allergic inflammation is modifiable by tocopherol isoforms, differential regulation by tocopherol isoforms provide a foundation for development of interventions to improve lung function in disease and raise the possibility of early life dietary interventions to limit the development of lung disease.

Digoxin Exhibits Neuroprotective Properties in a Rat Model of Dementia

Alzheimer's disease (AD) is by far the most common cause of cognitive impairment in older adults. Current treatments are entirely focused on the symptoms of AD. A complex etiology for AD has been proposed recently, in which AD leads in elevated levels of inflammation. We previously studied digoxin's involvement in the sporadic-AD intracerebroventricular (ICV)-streptozotocin (STZ) animal model due to its anti-inflammatory and neuroprotective characteristics. 18 adult sprague-dawley rats were split into three groups: control (n = 6), STZ + Saline (n = 6), and STZ + Digoxin (n = 6). Twelve AD-induced rats were split into two groups using stereotaxy five days after STZ injection (3 mg/kg) into both lateral ventricles: one group got digoxin (0.1 mg/kg/day, i.p.) for three weeks, while the other group received saline. Following treatment, each subject was subjected to a passive avoidance learning (PAL) test, followed by brain tissue harvesting. The levels of tumor necrosis factor-alpha (TNF-α) and choline acetyl transferase (ChAT) were measured in the brain, and neurons were counted using Cresyl violet staining in cornu ammonis-1 (CA1) and cornu ammonis-3 (CA3) cornu ammonis (CA3). ICV-STZ significantly shortened PAL latency, increased brain TNF-α levels, decreased brain ChAT activity, and decreased hippocampus neuron number. On the other hand, digoxin significantly reduced all of these STZ-induced deleterious effects. Digoxin significantly rescued rats from memory loss caused by ICV-STZ by decreasing hippocampal cell death, neuroinflammation, and cholinergic deficiency. These findings suggest that digoxin may be beneficial in treating cognitive impairment and Alzheimer's disease.

Allergen disrupts amygdala-respiration coupling

Allergic asthma affects both the respiratory function and central nervous system. Communication between the amygdala and respiratory control system is critical for regulating breathing function. To date, no study provides the effect of allergic inflammation on amygdala-respiration coupling. Here, we simultaneously recorded respiration and local field potentials of the amygdala during awake immobility in a rat model of allergic asthma. A decreased synchrony was found between amygdala and respiration in asthmatic rats. Allergen also reduced the modulatory effect of the respiration phase on amygdala power at delta, theta and gamma2 (80-120 Hz) frequencies. Moreover, in the animal model of allergic asthma, delta and theta oscillations strongly coordinate local gamma2 activity in the amygdala. These findings suggest that allergen can induce brain alterations and therefore shed light on future works to address how disruption of amygdala-respiration coupling contributes to respiratory dysfunction in allergic asthma.

Activation of Dopamine D2 Receptor Alleviates Neuroinflammation in a Mouse Model of Allergic Rhinitis With Olfactory Dysfunction

Purpose

Allergic rhinitis (AR) is a common otolaryngology disease and one of the clinical causes of olfactory dysfunction (OD). The olfactory bulb serves as a transfer station for olfactory information transmission, and alleviating its neuroinflammation may be expected to improve AR-induced OD. Recent studies have suggested that the dopamine D2 receptor acts as a key target in regulating immune functions and neuroinflammatory reaction. However, the effect of dopamine D2 receptor on AR-induced neuroinflammation is still unknown.

Methods

An AR mouse model with OD induced by ovalbumin were constructed. The buried food pellet test was to evaluate the olfactory function of the mice. Immunofluorescence staining, hematoxylin and eosin staining, enzyme-linked immunosorbent assay and western blotting were also used to investigate the molecular mechanisms underlying the anti-inflammatory effects of the dopamine D2 receptor in AR-induced OD.

Results

We found that AR-induced OD has a relationship with inflammatory responses in the olfactory bulb. Nasal administration of quinpirole (Quin, a dopamine D2 receptor agonist, 3 mg/kg) improved olfactory function in mice, inhibited the expression of toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signalings and the levels of tumor necrosis factor-α, interleukin (IL)-1β and IL-6 in the olfactory bulb. In vitro, Quin (20 μmol/L) inhibited the release of TLR4/NF-κB signalings-dependent inflammatory cytokines in cultured microglia.

Conclusions

Activation of the dopamine D2 receptor inhibits the release of inflammatory cytokines through TLR4/NF-κB signaling in the olfactory bulb microglia, and protects olfactory function.

Anxiety, depression, and asthma: New perspectives and approaches for psychoneuroimmunology research

The field of psychoneuroimmunology has advanced the understanding of the relationship between immunology and mental health. More work can be done to advance the field by investigating the connection between internalizing disorders and persistent airway inflammation from asthma and air pollution exposure. Asthma is a prominent airway condition that affects about 10% of developing youth and 7.7% of adults in the United States. People who develop with asthma are at three times increased risk to develop internalizing disorders, namely anxiety and depression, compared to people who do not have asthma while developing. Interestingly, sex differences also exist in asthma prevalence and internalizing disorder development that differ based on age. Exposure to air pollution also is associated with increased asthma and internalizing disorder diagnoses. New perspectives of how chronic inflammation affects the brain could provide more understanding into internalizing disorder development. This review on how asthma and air pollution cause chronic airway inflammation details recent preclinical and clinical research that begins to highlight potential mechanisms that drive comorbidity with internalizing disorder symptoms. These findings provide a foundation for future studies to identify therapies that can simultaneously treat asthma and internalizing disorders, thus potentially decreasing mental health diagnoses in asthma patients.

Asthma and posttraumatic stress disorder (PTSD): Emerging links, potential models and mechanisms

Posttraumatic stress disorder (PTSD) is a highly prevalent, debilitating mental health condition. A better understanding of contributory neurobiological mechanisms will lead to effective treatments, improving quality of life for patients. Given that not all trauma-exposed individuals develop PTSD, identification of pre-trauma susceptibility factors that can modulate posttraumatic outcomes is important. Recent clinical evidence supports a strong link between inflammatory conditions and PTSD. A particularly strong association has been reported between asthma and PTSD prevalence and severity. Unlike many other PTSD-comorbid inflammatory conditions, asthma often develops in children, sensitizing them to subsequent posttraumatic pathology throughout their lifetime. Currently, there is a significant need to understand the neurobiology, shared mechanisms, and inflammatory mediators that may contribute to comorbid asthma and PTSD. Here, we provide a translational perspective of asthma and PTSD risk and comorbidity, focusing on clinical associations, relevant rodent paradigms and potential mechanisms that may translate asthma-associated inflammation to PTSD development.

Enhancement of Oxytocin in the Medial Prefrontal Cortex Reverses Behavioral Deficits Induced by Repeated Ketamine Administration in Mice

Ketamine is a popular recreational substance of abuse that induces persistent behavioral deficits. Although disrupted oxytocinergic systems have been considered to modulate vulnerability to developing drugs of abuse, the involvement of central oxytocin in behavioral abnormalities caused by chronic ketamine has remained largely unknown. Herein, we aimed to investigate the potential role of oxytocin in the medial prefrontal cortex (mPFC) in social avoidance and cognitive impairment resulting from repeated ketamine administration in mice. We found that ketamine injection (5 mg/kg, i.p.) for 10 days followed by a 6-day withdrawal period induced behavioral disturbances in social interaction and cognitive performance, as well as reduced oxytocin levels both at the periphery and in the mPFC. Repeated ketamine exposure also inhibited mPFC neuronal activity as measured by a decrease in c-fos-positive cells. Furthermore, direct microinjection of oxytocin into the mPFC reversed the social avoidance and cognitive impairment following chronic ketamine exposure. In addition, oxytocin administration normalized ketamine-induced inflammatory cytokines including TNF-α, IL-6, and IL-1β levels. Moreover, the activation of immune markers such as neutrophils and monocytes, by ketamine was restored in oxytocin-treated mice. Finally, the reversal effects of oxytocin on behavioral performance were blocked by pre-infusion of the oxytocin receptor antagonist atosiban into the mPFC. These results demonstrate that enhancing oxytocin signaling in the mPFC is a potential pathway to reverse social avoidance and cognitive impairment caused by ketamine, partly through inhibition of inflammatory stimulation.

Loss of APP in mice increases thigmotaxis and is associated with elevated brain expression of IL-13 and IP-10/CXCL10

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that leads to memory loss and is often accompanied by increased anxiety. Although AD is a heterogeneous disease, dysregulation of inflammatory pathways is a consistent event. Interestingly, the amyloid precursor protein (APP), which is the source of the amyloid peptide Aβ, is also necessary for the efficient regulation of the innate immune response. Here, we hypothesize that loss of APP function in mice would lead to cognitive loss and anxiety behavior, both of which are typically present in AD, as well as changes in the expression of inflammatory mediators. To test this hypothesis, we performed open field, Y-maze and novel object recognition tests on 12-18-week-old male and female wildtype and App^KO mice to measure thigmotaxis, short-term spatial memory and long-term recognition memory. We then performed a quantitative multiplexed immunoassay to measure levels of 32 cytokines/chemokines associated with AD and anxiety. Our results showed that App^KO mice, compared to wildtype controls, experienced increased thigmotactic behavior but no memory impairments, and this phenotype correlated with increased IP-10 and IL-13 levels. Future studies will determine whether dysregulation of these inflammatory mediators contributes to pathogenesis in AD.

Early postnatal allergic airway inflammation induces dystrophic microglia leading to excitatory postsynaptic surplus and autism-like behavior

Microglia play key roles in synaptic pruning, which primarily occurs from the postnatal period to adolescence. Synaptic pruning is essential for normal brain development and its impairment is implicated in neuropsychiatric developmental diseases such as autism spectrum disorders (ASD). Recent epidemiological surveys reported a strong link between ASD and atopic/allergic diseases. However, few studies have experimentally investigated the relationship between allergy and ASD-like manifestations, particularly in the early postnatal period, when allergic disorders occur frequently. Therefore, we aimed to characterize how allergic inflammation in the early postnatal period influences microglia and behavior using mouse models of short- and long-term airway allergy. Male mice were immunized by an intraperitoneal injection of aluminum hydroxide and ovalbumin (OVA) or phosphate-buffered saline (control) on postnatal days (P) 3, 7, and 11, followed by intranasal challenge with OVA or phosphate-buffered saline solution twice a week until P30 or P70. In the hippocampus, Iba-1-positive areas, the size of Iba-1-positive microglial cell bodies, and the ramification index of microglia by Sholl analysis were significantly smaller in the OVA group than in the control group on P30 and P70, although Iba-1-positive microglia numbers did not differ significantly between the two groups. In Iba-1-positive cells, postsynaptic density protein 95 (PSD95)-occupied areas and CD68-occupied areas were significantly decreased on P30 and P70, respectively, in the OVA group compared with the control group. Immunoblotting using hippocampal tissues demonstrated that amounts of PSD95, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor 2, and N-methyl-D-aspartate (NMDA) receptor 2B were significantly increased in the OVA group compared with the control group on P70, and a similar increasing trend for PSD95 was observed on P30. Neurogenesis was not significantly different between the two groups on P30 or P70 by doublecortin immunohistochemistry. The social preference index was significantly lower in the three chamber test and the number of buried marbles was significantly higher in the OVA group than in the control group on P70 but not on P30, whereas locomotion and anxiety were not different between the two groups. Compared with the control group, serum basal corticosterone levels were significantly elevated and hippocampal glucocorticoid receptor (GR) amounts and nuclear GR translocation in microglia, but not in neurons or astrocytes, were significantly decreased in the OVA group on P70 but not on P30. Gene set enrichment analysis of isolated microglia revealed that genes related to immune responses including Toll-like receptor signaling and chemokine signaling pathways, senescence, and glucocorticoid signaling were significantly upregulated in the OVA group compared with the control group on P30 and P70. These findings suggest that early postnatal allergic airway inflammation induces dystrophic microglia that exhibit defective synaptic pruning upon short- and long-term allergen exposure. Furthermore, long-term allergen exposure induced excitatory postsynaptic surplus and ASD-like behavior. Hypothalamo-pituitary-adrenal axis activation and the compensatory downregulation of microglial GR during long-term allergic airway inflammation may also facilitate these changes.

Neuroprotective effects of dexpanthenol on streptozotocin-induced neuronal damage in rats

AIM

Although the most common age-related neurodegenerative disease defined by memory loss is Alzheimer's disease (AD), only symptomatic therapies are present. A complex pathway for the AD pathogenesis that includes an increase in inflammation has recently been suggested. Since in previous animal experiments dexpanthenol has anti-inflammatory and neuroprotective activities, effects and role of dexpanthenol in an intracerebroventricular (ICV)-streptozotocin (STZ) induced sporadic-AD(memory impairment) animal model have been examined.

DESIGN AND METHODS

In total, 18 adult sprague-dawley rats were classified into 3 groups; control (n = 6), STZ + Saline (n = 6) and STZ + Dexpanthenol (n = 6). Twelve AD-induced rats through STZ-injection (3 mg/kg) into both lateral ventricles via stereotaxy were separated into two groups five days after STZ administration: one of these groups was treated with dexpanthenol (1000 mg/kg/day, i.p.) for 3 weeks and the other with saline. A passive avoidance learning (PAL) test was used after treatment, followed by brain tissue extraction in all subjects. Brain levels of tumor necrosis factor-alpha (TNF-α) and choline acetyl transferase (ChAT) were measured and Cresyl violet staining was used to count neurons in cornu ammonis-1 (CA1) and cornu ammonis-3 (CA3).

RESULTS

It was observed that ICV-STZ significantly shortened PAL latency, increased levels of TNF-α in brain, decreased activity of ChAT in brain, and number of hippocampal neurons. However, dexpanthenol significantly reduced all of those STZ-induced harmful effects.

CONCLUSION

Dexpanthenol significantly prevented the memory deficit induced by ICV-STZ through mitigating neuronal loss in hippocampus, cholinergic deficiency and neuroinflammation in rats. These findings suggest that dexpanthenol may be beneficial for treating memory impairment.

Serum Levels of Interleukin-6 and Tumor Necrosis Factor Alpha in Children With Attention-Deficit Hyperactivity Disorder

Background:

Attention-deficit hyperactivity disorder (ADHD) is a common disorder in children, but its etiology and pathogenesis are still unclear.

Aims:

The aims of this study were to measure the level of serum interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) as markers of immune system involvement in children with ADHD, and to study their correlation with symptoms severity of ADHD.

Materials and Methods:

The study was conducted on 80 children diagnosed as ADHD based on the criteria adapted from the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition. Eighty healthy children of matched age and sex served as a control group. All children enrolled in the study were subjected to history taking, clinical examination, and psychometric tests. Assay for serum IL-6 and TNF-α for all patients and controls was performed using enzyme-linked immunosorbent assay.

Results:

The mean serum level of IL-6 was 26.11 ± 11.14 and 6.23 ± 2.52 in children with ADHD and controls, respectively. Children with ADHD showed significantly higher serum IL-6 levels than the control group (P = 0.001). Serum IL-6 showed no significant correlation with the intelligence quotient (IQ) or the Abbreviated Conners’ Rating Scale scores for parents. However, TNF-α showed no significant differences between the two groups and no significant correlation with the IQ or the Abbreviated Conners’ Rating Scale scores for parents.

Conclusion:

Serum IL-6 levels were significantly higher in children with ADHD compared to controls; however, the IL-6 levels did not correlate with ADHD symptoms severity. Increased IL-6 levels may contribute to the etiology of ADHD.

TAK-242 ameliorates olfactory dysfunction in a mouse model of allergic rhinitis by inhibiting neuroinflammation in the olfactory bulb

OBJECTIVE

Olfactory dysfunction (OD) is a common symptom of allergic rhinitis (AR) that can seriously affect patient quality of life; however, the associated pathogenesis remains unclear. This study aimed to explore the relationship between OD and damage of the olfactory bulb (OB) in allergic rhinitis (AR). The therapeutic potential of TAK-242, a selective TLR4 inhibitor, was evaluated for OD.

METHOD

An AR mouse model was established with ovalbumin (OVA) to test the olfactory function of AR mice using the buried food pellet test (BFPT). Mice with OD were intraperitoneally injected with TAK-242 or 1% DMSO (vehicle). Immunohistochemistry was used to detect microglia and astrocyte activation in the OB. TUNNEL staining was performed to detect apoptosis in the OB. Proteins in the TLR4 signaling pathway were detected by Western blot. The level of proinflammatory factor mRNA in the OB was determined by RT-PCR.

RESULT

Neuroinflammation was observed in the OB of the OD group, as evidenced by glial cell activation and increased proinflammatory factor expression. The number of apoptotic cells was significantly increased in the OB of the OD group. The expression of TLR4, MyD88, and p-NF-κBp65 was significantly up-regulated in the OB of the OD group. TAK-242 treatment significantly reduced the level of IL-1β, IL-6, and TNF-α mRNA expression, as well as activation of microglia and astrocytes in the OB tissues.

CONCLUSION

TAK-242 improve olfactory function in AR mice mainly by reducing neuroinflammation and apoptosis in the OB, which may be related to blocking the TLR4/MyD88/NF-κB signaling pathway.

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.

Toxoplasma gondii, Suicidal Behavior, and Intermediate Phenotypes for Suicidal Behavior

Within the general literature on infections and suicidal behavior, studies on Toxoplasma gondii (T. gondii) occupy a central position. This is related to the parasite's neurotropism, high prevalence of chronic infection, as well as specific and non-specific behavioral alterations in rodents that lead to increased risk taking, which are recapitulated in humans by T. gondii's associations with suicidal behavior, as well as trait impulsivity and aggression, mental illness and traffic accidents. This paper is a detailed review of the associations between T. gondii serology and suicidal behavior, a field of study that started 15 years ago with our publication of associations between T. gondii IgG serology and suicidal behavior in persons with mood disorders. This "legacy" article presents, chronologically, our primary studies in individuals with mood disorders and schizophrenia in Germany, recent attempters in Sweden, and in a large cohort of mothers in Denmark. Then, it reviews findings from all three meta-analyses published to date, confirming our reported associations and overall consistent in effect size [ranging between 39 and 57% elevation of odds of suicide attempt in T. gondii immunoglobulin (IgG) positives]. Finally, the article introduces certain links between T. gondii and biomarkers previously associated with suicidal behavior (kynurenines, phenylalanine/tyrosine), intermediate phenotypes of suicidal behavior (impulsivity, aggression) and state-dependent suicide risk factors (hopelessness/dysphoria, sleep impairment). In sum, an abundance of evidence supports a positive link between suicide attempts (but not suicidal ideation) and T. gondii IgG (but not IgM) seropositivity and serointensity. Trait impulsivity and aggression, endophenotypes of suicidal behavior have also been positively associated with T. gondii seropositivity in both the psychiatrically healthy as well as in patients with Intermittent Explosive Disorder. Yet, causality has not been demonstrated. Thus, randomized interventional studies are necessary to advance causal inferences and, if causality is confirmed, to provide hope that an etiological treatment for a distinct subgroup of individuals at an increased risk for suicide could emerge.

Chronic Airway Allergy Induces Pro-Inflammatory Responses in the Brain of Wildtype Mice but Not 3xTgAD Mice

The effects of systemic inflammation on the pathogenesis of Alzheimer's disease (AD) are not clarified, both beneficial and deleterious effects being reported. Allergy is accompanied by a systemic inflammatory response and some epidemiological studies have reported a positive association between a history of allergy/asthma and dementia. To investigate whether chronic airway allergy influences the inflammatory status in the brain, AD-like pathology, and behaviour in relation to AD, we induced chronic airway allergy in triple transgenic AD (3xTgAD) and wildtype (WT) mice by repeated exposure to ovalbumin (OVA) as allergen. Behavioural tests relevant for hippocampus-dependent behaviour were performed. We found that allergy significantly increased the brain levels of immunoglobulin (Ig) G, IgE. In 3xTgAD mice, allergy increased the levels of decay accelerating factor and decreased the phosphorylation of p38. In contrast, allergy increased the levels of interleukin (IL)-1β and complement component 1q (C1q) in WT mice. Bronchoalveolar lavage fluid analysis confirmed eosinophilia in both genotypes, but the basal levels of eosinophils were lower in 3xTgAD mice. In summary, allergy induced predominantly anti-inflammatory effects in 3xTgAD mice, and pro-inflammatory effects in WT mice, thus being another potential factor to be considered when studying AD pathogenesis.

Anti-Yo Antibodies in Children With ADHD: First Results About Serum Cytokines

Objective: We investigated whether ADHD children who are positive to Purkinje cell antibodies display pro-inflammatory activity associated with high cytokine serum levels. Method: Fifty-eight ADHD outpatients were compared with 36 healthy, age- and sex-matched children. Forty-five of the ADHD children were positive to anti-Yo antibodies, whereas 34 of the control children were negative. Interleukin 4 (IL-4), IL-6, IL-10, IL-17, tumor necrosis factor alpha (TNFα), and interferon gamma (IFNγ) cytokine serum levels were tested in ADHD children who were positive to anti-Yo antibodies and in the control children who were negative. Results: Anti-Yo antibodies were present to a greater extent in the ADHD group: 77.58% versus 22.42%. Significant differences emerged between the two groups in IL-6 and IL-10, with higher cytokine levels being detected in ADHD children than in controls. Conclusion: Immune processes in ADHD are likely to be associated with mediators of inflammation, such as cytokines. These results contribute to our understanding of action of neural antibodies and cytokines in ADHD.

Development and Characterization of an Allergic Asthma Rat Model for Interventional Studies

Allergic asthma is one of the most common chronic diseases of the airways, however it still remains underdiagnosed and hence undertreated. Therefore, an allergic asthma rat model would be useful to be applied in future therapeutic strategy studies. The aim of the present study was to develop an objective model of allergic asthma in atopic rats that allows the induction and quantification of anaphylactic shock with quantitative variables. Female Brown Norway rats were intraperitoneally sensitized with ovalbumin (OVA), alum and Bordetella pertussis toxin and boosted a week later with OVA in alum. At day 28, all rats received an intranasal challenge with OVA. Anaphylactic response was accurately assessed by changes in motor activity and body temperature. Leukotriene concentration was determined in the bronchoalveolar lavage fluid (BALF), and total and IgE anti-OVA antibodies were quantified in blood and BALF samples. The asthmatic animals' motility and body temperature were reduced after the shock for at least 20 h. The asthmatic animals developed anti-OVA IgE antibodies both in BALF and in serum. These results show an effective and relatively rapid model of allergic asthma in female Brown Norway rats that allows the quantification of the anaphylactic response.

Interleukin-1α in the ventral hippocampus increases stress vulnerability and inflammation-related processes

Mechanisms of stress vulnerability remain elusive. Previous research demonstrated that inflammation-related processes in the brain play a role in stress vulnerability. Our previous research showed that inflammatory processes in the ventral hippocampus (vHPC) induced a stress vulnerable phenotype. To further understand neuroinflammatory processes in the vHPC in stressed rats, we determined that protein levels of the pro-inflammatory cytokine interleukin-1-α (IL-1α), but not interleukin-1β (IL-1β), were increased in the vHPC of rats vulnerable to the effects of repeated social defeat compared to rats resilient to its effects. Injections of IL-1α into the vHPC increased stress vulnerability as characterized by increases in passive coping during defeat and subsequent decreased social interactions. Conversely, injections of recombinant IL-1 receptor antagonist (IL1-RA) increased latencies to social defeat and decreased anxiety-like behaviors during social interaction, suggesting an reduction in stress vulnerability. Protein analyses revealed increased FosB expression in the vHPC of IL-1α-injected rats, and increased HPA activation following a social encounter. Further analysis of vHPC of IL1-α-injected rats showed increased density of microglia, increased expression of the pro-inflammatory cytokine HMGB1, and increases in a marker for vascular remodeling. Taken together, these data show increasing IL-1α during stress exposure is sufficient to produce a stress vulnerable phenotype potentially by increasing inflammation-related processes in the vHPC.LAY SUMMARYOur previous research demonstrated that inflammation-related processes in the brain play a role in inducing vulnerability to the effects of repeated social stress in rats. Here we demonstrate that a pro-inflammatory cytokine interleukin-1-α (IL-1α) induces inflammatory processes in the vHPC and behavioral vulnerability in stressed rats, whereas blocking IL receptors produces the opposite effects on behavioral vulnerability. Together, these results identify a substrate in the vHPC that produces vulnerability to stress by increasing inflammation-related processes in the vHPC.

Headliner in Physiology and Management of Childhood Asthma: Hypothalamic-Pituitary-Adrenal Axis

Asthma is the most common chronic inflammatory disease of children. Inhaled corticosteroids (ICS) are the cornerstone of asthma therapy which are the most effective, commonly used treatment of persistent asthma. Mostly, studies on the relationship between asthma and cortisol have focused on side effects of treatment. Recently, asthmatic patients not treated with ICS have been reported to have an attenuated activity and/or responsiveness of their Hypothalamic-Pituitary- Adrenal (HPA) axis. Moreover, it has been proposed that asthma worsening with stress may be due to a dysfunctional HPA axis, or cortisol insensitivity due to chronic psychological stress through impaired glucocorticoid receptor expression or function. Although long-term ICS treatment might produce adrenal suppression or iatrogenic Cushing syndrome, improvement of adrenal function has also been detected in some of asthmatic cases. Thus, the response scheme of HPA axis still contains undiscovered features in asthma. The management of asthma can be improved by increasing knowledge on the role of HPA axis in asthma pathophysiology. The risk for side effects of ICS can be minimized through increased awareness, early recognition of at-risk patients and regular patient follow-up. This review was written to draw attention to the role of HPA axis in both asthma and its treatment and to illustrate a follow up algorithm of HPA axis in the management of asthma.

Allergen-induced anxiety-like behavior is associated with disruption of medial prefrontal cortex - amygdala circuit

Anxiety is prevalent in asthma, and is associated with disease severity and poor quality of life. However, no study to date provides direct experimental evidence for the effect of allergic inflammation on the structure and function of medial prefrontal cortex (mPFC) and amygdala, which are essential regions for modulating anxiety and its behavioral expression. We assessed the impact of ovalbumin (OVA)-induced allergic inflammation on the appearance of anxiety-like behavior, mPFC and amygdala volumes using MRI, and the mPFC-amygdala circuit activity in sensitized rats. Our findings exhibited that the OVA challenge in sensitized rats induced anxiety-like behavior, and led to more activated microglia and astrocytes in the mPFC and amygdala. We also found a negative correlation between anxiety-like behavior and amygdala volume. Moreover, OVA challenge in sensitized rats was associated with increases in mPFC and amygdala activity, elevation of amygdala delta-gamma coupling, and the enhancement of functional connectivity within mPFC-amygdala circuit – accompanied by an inverted direction of information transferred from the amygdala to the mPFC. We indicated that disrupting the dynamic interactions of the mPFC-amygdala circuit may contribute to the induction of anxiety-related behaviors with asthma. These findings could provide new insight to clarify the underlying mechanisms of allergic inflammation-induced psychiatric disorders related to asthma.

More sneezing, less crime? Health shocks and the market for offenses

A large literature points out that exposure to criminal victimization has far-reaching effects on public health. What remains surprisingly unexplored is that role that health shocks play in explaining aggregate fluctuations in offending. This research finds novel evidence that crime is sensitive to health shocks. We consider the responsiveness of crime to a pervasive and common health shock which we argue shifts costs and benefits for offenders and victims: seasonal allergies. Leveraging daily variation in city-specific pollen counts, we present evidence that violent crime declines in U.S. cities on days in which the local pollen count is unusually high and that these effects are driven by residential violence. While past literature suggests that property crimes have more instrumental motives, require planning, and hence are particularly sensitive to permanent changes in the cost and benefits of crime, we find that violence may be especially sensitive to health shocks.

Distraction of olfactory bulb-medial prefrontal cortex circuit may induce anxiety-like behavior in allergic rhinitis

Allergic rhinitis is a chronic inflammatory disease of the upper respiratory tract, which is associated with high incidence of anxiety symptom. There is evidence that medial prefrontal cortex modulates anxiety-related behaviors and receives projections from olfactory bulb. Since olfactory dysfunction has been reported in allergic rhinitis, we aimed to evaluate anxiety-like behavior and oscillations of olfactory bulb-medial prefrontal cortex circuit in an animal model of allergic rhinitis. The number of open arm entries in elevated zero maze was significantly reduced in sensitized rats exposed to intranasal ovalbumin compared to the control group, which was indicating the enhancement of anxiety-like behavior in allergic rhinitis animals. Analysis of local field potentials in olfactory bulb and medial prefrontal cortex during immobility and exploration state showed that anxiety-like behavior induced by allergic rhinitis was in association with increased activity of medial prefrontal cortex and enhancement of olfactory bulb-medial prefrontal cortex coupling in delta and theta bands. Moreover, in allergic rhinitis animals, theta strongly coordinates local gamma activity in olfactory bulb and medial prefrontal cortex, which means to have a strong local theta/gamma coupling. We suggested that disruption of olfactory bulb-medial prefrontal cortex circuit due to allergic reactions might have a governing role for inducing anxiety-like behavior in the allergic rhinitis experimental model.

Mood Worsening on Days with High Pollen Counts is associated with a Summer Pattern of Seasonality

Background:

Summer/spring-type seasonal affective disorder (S-SAD) is the less common subtype of seasonal affective disorder and evidence regarding potential triggers of S-SAD is scarce. Recent reports support association of airborne-pollen with seasonal exacerbation of depression (mood seasonality) and timing of suicidal behavior. Therefore, we hypothesized that Old Order Amish (OOA) with summer/spring pattern of seasonality (abbreviated as summer pattern) and S-SAD will have significant mood worsening on high pollen days.

Methods:

A seasonal pattern of mood worsening and SAD parameters were estimated using Seasonal Pattern Assessment Questionnaire (SPAQ). Age- and gender-adjusted ANCOVAs and post hoc analyses were conducted to compare mood worsening on days with high pollen counts between summer-pattern vs no-summer-pattern of mood worsening, S-SAD vs no-S-SAD, winter-pattern vs no-winter-pattern of mood worsening, and W-SAD vs no-W-SAD groups.

Results:

The prevalence of S-SAD was 0.4%, while 4.5% of individuals had a summer pattern of mood seasonality. A statistically significant difference for mood worsening on high pollen days was observed between summer-pattern vs no-summer-pattern of mood worsening (p = 0.006). The significant association between S-SAD vs no-SAD groups (p = 0.032) for mood worsening on high pollen days did not withstand Bonferroni adjustment for multiple comparisons. No significant association was found for winter-pattern vs no-winter-pattern of mood worsening (p = 0.61) and for W-SAD vs no-W-SAD (p = 0.19) groups.

Conclusion:

Our results are consistent with previous studies implicating links between aeroallergen exposure and summer pattern of seasonality, but not the winter pattern of seasonality.

Risk factors analysis of attention deficit/hyperactivity disorder and allergic rhinitis in children: a cross-sectional study

Background

To investigate the relationship between symptom of attention-deficit/hyperactivity disorder (ADHD) and allergic rhinitis (AR) in AR children of different genders and ages.

Methods

Four hundred and sixty-five allergic rhinitis children aged 6–12 years old were recruited in this study. Skin-prick test, Pediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ), Total Nasal Symptoms Score (TNSS) and the Swanson, Nolan, and Pelham version IV scale (SNAP-IV) were recorded. Patients were divided into AR with ADHD and AR without ADHD, according to the SNAP-IV scale results.

Results

Children with the inattention/hyperactivity scale (IHS) > 1.25 accounted for 26.4% of all children with AR. The TNSS with IHS > 1.25 group were significantly higher than the IHS ≤ 1.25 group. Univariate analysis showed that age, gender, duration of AR symptoms, skin index, and PRQLQ subscales were associated with symptoms of hyperactivity and attention deficit (IHS > 1.25). After normalizing the age and gender factors, duration of AR symptoms and skin index correlated with IHS > 1.25. After stratifying age and gender, the correlation between IHS > 1.25 and skin index and PRQLQ subscales was mainly found in male children, and the association between the duration of AR symptoms and IHS > 1.25 was reflected in each group.

Conclusions

ADHD in children with AR is associated with severity, duration, and skin index of AR, and this association is more pronounced in male children.

Electronic supplementary material

The online version of this article (10.1186/s13052-019-0703-1) contains supplementary material, which is available to authorized users.

Allergies, asthma, and psychopathology in a nationally-representative US sample

BACKGROUND

Symptoms of depressed mood and anxiety have been associated with immune dysregulation and atopic disorders, however it is unclear whether this relationship spans other forms of psychopathology. The objective of this study was to use a large, population-based sample to examine the association between several common psychiatric conditions and two atopic disorders: seasonal allergies and asthma. This study also examined whether comorbidity between psychiatric disorders confounded the relationship between atopy and each psychiatric disorder.

METHODS

Data come from the Comprehensive Psychiatric Epidemiology Surveys, a nationally-representative sample of US adults (N = 10,309). Lifetime history of major depressive disorder (MDD), generalized anxiety disorder (GAD), panic disorder (PD), and post-traumatic stress disorder (PTSD) was assessed using the Composite International Diagnostic Inventory. History of seasonal allergies and asthma were assessed by self-report. Weighted logistic regression was used to evaluate the association between allergies and asthma and psychopathology. Psychiatric comorbidities were also examined as potential confounders.

RESULTS

Approximately 36.6% had a history of allergies and 11.5% a history of asthma. Seasonal allergies were positively associated with odds of MDD (Odds ratio (OR): 1.24, 95% Confidence Interval (CI): 1.06-1.46), GAD (OR: 1.54 (1.28-1.84)), PD (OR: 1.54 (1.24-1.91)), and PTSD (OR: 1.32 (1.09-1.59)). Asthma was not significantly associated with any psychiatric disorder. All significant associations persisted after adjustment for psychiatric comorbidities.

LIMITATIONS

Limitations include self-reporting of atopic disorder status and of all disorder ages of onset.

CONCLUSIONS

This study confirms the association between MDD and PD and seasonal allergies, and extends this relationship to GAD and PTSD.

The neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in adolescent obsessive-compulsive disorder: Does comorbid anxiety disorder affect inflammatory response?

Recent adult etiologic studies indicated evidence linking increased inflammatory parameters with psychiatric disorders. The neutrophil-lymphocyte ratio and platelet-lymphocyte ratio are easily obtainable clinical markers of inflammation and have been found to be increased in various medical and mental disorders. In this study, we aimed to investigate the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in adolescents with obsessive-compulsive disorder (OCD). Secondarily, the effect of comorbid anxiety disorder with OCD on the inflammatory response was investigated. Sixty drug-naïve adolescents with OCD aged 12 to 18 years were enrolled in the patient group. Twenty-three of the OCD group had comorbid anxiety disorder (AD) and 37 had no comorbidities. One hundred twenty-eight adolescents in the same age range with no psychiatric disorders were recruited as the healthy control group. The severity of OCD symptoms was evaluated using the Children's Yale-Brown Obsessive Compulsive Scale. There were statistically significant differences in the neutrophil-lymphocyte ratio, white blood cell, neutrophil, and platelet counts among the three groups, even after adjusting for age and sex. The adolescents with OCD and AD had the highest neutrophil-lymphocyte ratio and white blood cell counts. A comorbid anxiety disorder diagnosis in addition to obsessive-compulsive disorder may increase the inflammatory response.

Asthma Induction During Development and Adult Lung Function, Behavior and Brain Gene Expression

In developing youth, allergic asthma is the most common chronic condition, with 9%–10% of youth affected. Asthma onset during childhood and adolescence is further associated with other health issues, particularly psychiatric conditions. To understand causal mechanisms by which developmental asthma may lead to altered behavior, brain and health trajectories, we developed a mouse model of developmental allergic asthma. In the current study, we tested for potential long-term effects of developmental asthma on adult lung function and behavior and brain gene expression associated with emotion and stress regulation. We manipulated airway inflammation (AI) and methacholine (MCH)-induced bronchospasm (resulting in labored breathing, LB) in young male and female BALB/cJ mice and measured adult outcomes 3 months after final asthma manipulations. Results indicated that allergen exposure, used to cause AI, and which ended on post-natal day 56 (P56), led to persistent lung AI, mucus buildup and gene expression related to allergic asthma 3 months after final allergen exposure. In addition, at this same age, early allergen exposure led to altered brain gene expression related to stress regulation (prefrontal corticotropin releasing hormone receptor 1, Crhr1 and hippocampal glucocorticoid receptor, GR) and serotonin function (brainstem serotonin transporter, SERT). On the other hand, LB events during development led to altered anxiety-related behavior. Importantly, sex and pre-asthma fear-related behavior (ultrasonic vocalization, USV rates) modulated these adult outcomes. Asthma that develops during childhood/adolescence may have long-term impacts on emotion and stress regulation mechanisms, and these influences may be moderated by sex and pre-asthma temperament.

CD8+ T cells promote cytokine responses to stress

Psychological stress is known to have profound effects on immune function and to promote inflammatory conditions. Elevated circulating levels of cytokines associated with stress are known to increase the risk to several diseases, but little is known about this mechanism. This study assessed the role of T cells on cytokine levels after exposure to stress in the learned helplessness paradigm. Adoptive transfer of CD4⁺ T cells into Rag2^-/- mice did not change cytokine levels to stress while CD8⁺ T cells resulted in an increase in TNF-α, IL-6 and IFN-γ in stressed Rag2^-/- mice. Moreover, depletion of CD8⁺ T cells in WT mice abolished these cytokine responses to stress. Corticosterone and behavioral stress responsiveness was impaired in Rag2^-/- mice reconstituted with CD8⁺ T cells. Notably, depletion of these cells in WT mice had no effect on behavior or corticosterone levels. Exposure to stress did not change the expression of canonical markers of T cell activation including CD62L and CD44 or modified intracellular cytokine content, suggesting that they are not the main producers of circulating cytokines in response to stress. These results show that CD8⁺ T cells promote TNF-α, IL-6 and IFN-γ responses to stress, possibly by stimulating non-lymphoid cells.

Evaluation of the neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, and mean platelet volume as inflammatory markers in children with attention-deficit hyperactivity disorder

AIM

The neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR), and mean platelet volume (MPV) have recently been used as indicators of a systemic inflammatory response. The aim of this study was to investigate the relations of the NLR, PLR, MLR, and MPV with attention-deficit hyperactivity disorder (ADHD).

METHODS

The study group consisting of 82 children diagnosed with ADHD was compared with a healthy control (HC) group of 70 age-, sex-, and body-mass-index-matched subjects. The NLR, PLR, MLR, and MPV were measured according to the complete blood count.

RESULTS

The NLR, PLR, MLR, MPV, and neutrophil count of the ADHD group were significantly higher than those of the HC group. The lymphocyte counts of the patients were significantly lower than those of the HC group.

CONCLUSION

Inflammation might play a role in the etiopathogenesis of ADHD. The NLR, PLR, MLR, and MPV may be potential inflammation markers for ADHD in children.

Allergic Rhinitis in Rats Is Associated with an Inflammatory Response of the Hippocampus

Allergic rhinitis (AR) is a major concern in personal and public health, which negatively affects emotions and behavior, leading to cognitive deficits, memory decline, poor school performance, anxiety, and depression. Several cellular and molecular mediators are released in the inflammatory process of AR and activate common neuroimmune mechanisms, involving emotionally relevant circuits and the induction of anxiety. Responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis to allergic processes have been reported, which may also include responsiveness of the hippocampus, cortex, and other brain regions. Here, we have used an optimized rat model of AR to explore whether the disease has a relationship with inflammatory responses in the hippocampus. AR was established in adult rats by ovalbumin sensitization, and the expression of various inflammatory substances in the hippocampus was measured by specific assays. Comparison between experimental and various control groups of animals revealed an association of AR with significant upregulation of substance P, microglia surface antigen (CD11b), glial fibrillary acid protein (GFAP), tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6) in the hippocampus. Thus, we hypothesize that the AR challenge may activate these inflammatory mediators in the hippocampus, which in turn contribute to the abnormal behavior and neurological deficits associated with AR.

Evidence of fatigue, disordered sleep and peripheral inflammation, but not increased brain TSPO expression, in seasonal allergy: A [11C]PBR28 PET study

Allergy is associated with non-specific symptoms such as fatigue, sleep problems and impaired cognition. One explanation could be that the allergic inflammatory state includes activation of immune cells in the brain, but this hypothesis has not been tested in humans. The aim of the present study was therefore to investigate seasonal changes in the glial cell marker translocator protein (TSPO), and to relate this to peripheral inflammation, fatigue and sleep, in allergy. We examined 18 patients with severe seasonal allergy, and 13 healthy subjects in and out-of pollen season using positron emission tomography (n = 15/13) and the TSPO radioligand [¹¹C]PBR28. In addition, TNF-α, IL-5, IL-6, IL-8 and IFN-γ were measured in peripheral blood, and subjective ratings of fatigue and sleepiness as well as objective and subjective sleep were investigated. No difference in levels of TSPO was seen between patients and healthy subjects, nor in relation to pollen season. However, allergic subjects displayed both increased fatigue, sleepiness and increased percentage of deep sleep, as well as increased levels of IL-5 and TNF-α during pollen season, compared to healthy subjects. Allergic subjects also had shorter total sleep time, regardless of season. In conclusion, allergic subjects are indicated to respond to allergen exposure during pollen season with a clear pattern of behavioral disruption and peripheral inflammatory activation, but not with changes in brain TSPO levels. This underscores a need for development and use of more specific markers to understand brain consequences of peripheral inflammation that will be applicable in human subjects.

Mouse Testing Methods in Psychoneuroimmunology 2.0: Measuring Behavioral Responses

The field of psychoneuroimmunology (PNI) aims to uncover the processes and consequences of nervous, immune, and endocrine system relationships. Behavior is a consequence of such interactions and manifests from a complex interweave of factors including immune-to-neural and neural-to-immune communication. Often the signaling molecules involved during a particular episode of neuroimmune activation are not known but behavioral response provides evidence that bioactives such as neurotransmitters and cytokines are perturbed. Immunobehavioral phenotyping is a first-line approach when examining the neuroimmune system and its reaction to immune stimulation or suppression. Behavioral response is significantly more sensitive than direct measurement of a single specific bioactive and can quickly and efficiently rule in or out relevance of a particular immune challenge or therapeutic to neuroimmunity. Classically, immunobehavioral research was focused on sickness symptoms related to bacterial infection but neuroimmune activation is now a recognized complication of diseases and disorders ranging from cancer to diabesity to Alzheimer's. Immunobehaviors include lethargy, loss of appetite, and disinterest in social activity/surrounding environment. In addition, neuroimmune activation can diminish physical activity, precipitate feelings of depression and anxiety, and impair cognitive and executive function. Provided is a detailed overview of behavioral tests frequently used to examine neuroimmune activation in mice with a special emphasis on pre-experimental conditions that can confound or prevent successful immunobehavioral experimentation.