The airway neuro-immune axis as a therapeutic target in allergic airway diseases.

Recent evidence has increasingly underscored the importance of the neuro-immune axis in mediating allergic airway diseases, such as allergic asthma and allergic rhinitis. The intimate spatial relationship between neurons and immune cells suggests that their interactions play a pivotal role in regulating allergic airway inflammation. Upon direct activation by allergens, neurons and immune cells engage in interactions, during which neurotransmitters and neuropeptides released by neurons modulate immune cell activity. Meanwhile, immune cells release inflammatory mediators such as histamine and cytokines, stimulating neurons and amplifying neuropeptide production, thereby exacerbating allergic inflammation. The dynamic interplay between the nervous and immune systems suggests that targeting the neuro-immune axis in the airway could represent a novel approach to treating allergic airway diseases. This review summarized recent evidence on the nervous system's regulatory mechanisms in immune responses and identified potential therapeutic targets along the peripheral nerve-immune axis for allergic asthma and allergic rhinitis. The findings will provide novel perspectives on the management of allergic airway diseases in the future.

The role of peripheral inflammatory insults in Alzheimer's disease: a review and research roadmap.

Peripheral inflammation, defined as inflammation that occurs outside the central nervous system, is an age-related phenomenon that has been identified as a risk factor for Alzheimer's disease. While the role of chronic peripheral inflammation has been well characterized in the context of dementia and other age-related conditions, less is known about the neurologic contribution of acute inflammatory insults that take place outside the central nervous system. Herein, we define acute inflammatory insults as an immune challenge in the form of pathogen exposure (e.g., viral infection) or tissue damage (e.g., surgery) that causes a large, yet time-limited, inflammatory response. We provide an overview of the clinical and translational research that has examined the connection between acute inflammatory insults and Alzheimer's disease, focusing on three categories of peripheral inflammatory insults that have received considerable attention in recent years: acute infection, critical illness, and surgery. Additionally, we review immune and neurobiological mechanisms which facilitate the neural response to acute inflammation and discuss the potential role of the blood-brain barrier and other components of the neuro-immune axis in Alzheimer's disease. After highlighting the knowledge gaps in this area of research, we propose a roadmap to address methodological challenges, suboptimal study design, and paucity of transdisciplinary research efforts that have thus far limited our understanding of how pathogen- and damage-mediated inflammatory insults may contribute to Alzheimer's disease. Finally, we discuss how therapeutic approaches designed to promote the resolution of inflammation may be used following acute inflammatory insults to preserve brain health and limit progression of neurodegenerative pathology.

Prenatal administration of multipotent adult progenitor cells modulates the systemic and cerebral immune response in an ovine model of chorioamnionitis.

Systemic and cerebral inflammation following antenatal infection (e.g. chorioamnionitis) and dysregulation of the blood brain barrier (BBB) are major risk factors for abnormal neonatal brain development. Administration of multipotent adult progenitor cells (MAPCs) represents an interesting pharmacological strategy as modulator of the peripheral and cerebral immune response and protector of BBB integrity. We studied the immunomodulatory and protective cerebrovascular potential of prenatally administered MAPCs in a preclinical ovine model for antenatal inflammation. Ovine fetuses were intra-amniotically (i.a.) exposed to lipopolysaccharide (LPS) or saline at gestational day 125, followed by the intravenous administration of 1*107 MAPCs or saline at gestational day 127. Circulating inflammation markers were measured. Fetal brains were examined immuno-histochemically post-mortem at gestational day 132. Fetal plasma IL-6 levels were elevated significantly 24 h after LPS administration. In utero systemic MAPC treatment after LPS exposure increased Annexin A1 (ANXA1) expression in the cerebrovascular endothelium, indicating enforcement of BBB integrity, and increased the number of leukocytes at brain barriers throughout the brain. Further characterisation of brain barrier-associated leukocytes showed that monocyte/choroid plexus macrophage (IBA-1+/CD206+) and neutrophil (MPO+) populations predominantly contributed to the LPS-MAPC-induced increase of CD45+cells. In the choroid plexus, the percentage of leukocytes expressing the proresolving mediator ANXA1 tended to be decreased after LPS-induced antenatal inflammation, an effect reversed by systemic MAPC treatment. Accordingly, expression levels of ANXA1 per leukocyte were decreased after LPS and restored after subsequent MAPC treatment. Increased expression of ANXA1 by the cerebrovasculature and immune cells at brain barriers following MAPC treatment in an infectious setting indicate a MAPC driven early defence mechanism to protect the neonatal brain against infection-driven inflammation and potential additional pro-inflammatory insults in the neonatal period.

Autonomic Nervous System Dysregulation and Osteoarthritis Pain: Mechanisms, Measurement, and Future Outlook.

PURPOSE OF REVIEW: The autonomic nervous system is an important regulator of stress responses and exhibits functional changes in chronic pain states. This review discusses potential overlap among autonomic dysregulation, osteoarthritis (OA) progression, and chronic pain. From this foundation, we then discuss preclinical to clinical research opportunities to close gaps in our knowledge of autonomic dysregulation and OA. Finally, we consider the potential to generate new therapies for OA pain via modulation of the autonomic nervous system. RECENT FINDINGS: Recent reviews provide a framework for the autonomic nervous system in OA progression; however, research is still limited on the topic. In other chronic pain states, functional overlaps between the central autonomic network and pain processing centers in the brain suggest relationships between concomitant dysregulation of the two systems. Non-pharmacological therapeutics, such as vagus nerve stimulation, mindfulness-based meditation, and exercise, have shown promise in alleviating painful symptoms of joint diseases, and these interventions may be partially mediated through the autonomic nervous system. The autonomic nervous system appears to be dysregulated in OA progression, and further research on rebalancing autonomic function may lead to novel therapeutic strategies for treating OA pain.

In Vitro Methodologies to Study the Role of Advanced Glycation End Products (AGEs) in Neurodegeneration.

Advanced glycation end products (AGEs) can be present in food or be endogenously produced in biological systems. Their formation has been associated with chronic neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis. The implication of AGEs in neurodegeneration is related to their ability to bind to AGE-specific receptors and the ability of their precursors to induce the so-called "dicarbonyl stress", resulting in cross-linking and protein damage. However, the mode of action underlying their role in neurodegeneration remains unclear. While some research has been carried out in observational clinical studies, further in vitro studies may help elucidate these underlying modes of action. This review presents and discusses in vitro methodologies used in research on the potential role of AGEs in neuroinflammation and neurodegeneration. The overview reveals the main concepts linking AGEs to neurodegeneration, the current findings, and the available and advisable in vitro models to study their role. Moreover, the major questions regarding the role of AGEs in neurodegenerative diseases and the challenges and discrepancies in the research field are discussed.

Production of the Cytokine VEGF-A by CD4+ T and Myeloid Cells Disrupts the Corneal Nerve Landscape and Promotes Herpes Stromal Keratitis.

Herpes simplex virus type 1 (HSV-1)-infected corneas can develop a blinding immunoinflammatory condition called herpes stromal keratitis (HSK), which involves the loss of corneal sensitivity due to retraction of sensory nerves and subsequent hyperinnervation with sympathetic nerves. Increased concentrations of the cytokine VEGF-A in the cornea are associated with HSK severity. Here, we examined the impact of VEGF-A on neurologic changes that underly HSK using a mouse model of HSV-1 corneal infection. Both CD4+ T cells and myeloid cells produced pathogenic levels of VEGF-A within HSV-1-infected corneas, and CD4+ cell depletion promoted reinnervation of HSK corneas with sensory nerves. In vitro, VEGF-A from infected corneas repressed sensory nerve growth and promoted sympathetic nerve growth. Neutralizing VEGF-A in vivo using bevacizumab inhibited sympathetic innervation, promoted sensory nerve regeneration, and alleviated disease. Thus, VEGF-A can shape the sensory and sympathetic nerve landscape within the cornea, with implications for the treatment of blinding corneal disease.

Effect of an 8-Week Yoga-Based Lifestyle Intervention on Psycho-Neuro-Immune Axis, Disease Activity, and Perceived Quality of Life in Rheumatoid Arthritis Patients: A Randomized Controlled Trial.

Various external stressors and environmental challenges lead to the provocation of the immune system in autoimmune diseases like Rheumatoid arthritis (RA). The inappropriate immune response further triggers the cascade of inflammatory changes resulting in precipitation of symptoms and hampers quality of life (QOL). The underlying psycho-somatic component of the disease requires a holistic approach to its treatment dimension rather than the use of pharmacotherapy. The applicability of mind-body interventions has become essential in today's fast-paced life. Yoga, a mind-body technique, alters the mind's capacity to facilitate systemic functioning at multiple organ system levels. Hence, we conducted this study to evaluate the impact of 8 weeks of a yoga-based lifestyle intervention (YBLI) on psycho-neuro-immune markers, gene expression patterns, and QOL in RA patients on routine medical therapy. A total of 66 patients were randomized into two groups: yoga group or non-yoga group and were assessed for a panel of inflammatory cytokines (IL-6, IL-17A, TNF-α, and TGF-ß), mind-body communicative markers (BDNF, DHEAS, ß-endorphin, and sirtuin) and transcript levels of various genes (IL-6, TNF-α, NFKB1, TGF-ß, and CTLA4). We assessed disease activity and QOL using the DAS28-ESR and WHOQOL-BREF questionnaire, respectively. Yoga group observed significant improvements in the levels of markers, which influenced the psycho-neuro-immune axis (p < 0.001) with an estimated effect size from small to medium range. In the yoga group, there was a significant reduction in DAS28-ESR (p < 0.001) and improvement seen in the physical health, psychological, social relationships domains (p < 0.001) of QOL, except environmental (p > 0.05). The yoga group showed downregulation of IL-6, TNF-α, and CTLA4 and upregulation of TGF-ß. These results suggest that a decrease in disease activity after yoga practice is associated with a significant reduction in inflammatory cytokines, the elevation of mind-body communicative markers, and normalization of various transcript levels, which improved QOL. Thus the adoption of YBLI improves clinical outcome in RA, and decreases systemic inflammation by its beneficial effects on psycho-neuro-immune axis and normalization of dysregulated transcripts. Thus YBLI may be used for RA patients as an adjunctive therapy.

The neuro-immune axis in cancer: Relevance of the peripheral nervous system to the disease.

The peripheral nervous system and the immune system are critically involved in the surveillance of our body, having the ability to sense the environment, recognize danger signals and orchestrate an appropriate response. Despite the fact that these two systems have been historically considered autonomous entities, a large body of evidence has shown how they interact in many homeostatic responses and how these interactions are critically involved in pathologic contexts too, including inflammation, infection and autoimmunity. In the context of cancer, where it is already known that inflammation plays a key role, the cross-regulation of immune cells and neural components is still somewhat unexplored. Detailed characterization of the mediators and pathways involved in neuro-immune interactions in cancer is expected to provide insights into the pathogenesis of disease and open new possibilities related to therapeutic strategies.

The Vagal Autonomic Pathway of COVID-19 at the Crossroad of Alzheimer's Disease and Aging: A Review of Knowledge.

Coronavirus Disease 2019 (COVID-19) pandemic-triggered mortality is significantly higher in older than in younger populations worldwide. Alzheimer's disease (AD) is related to aging and was recently reported to be among the major risk factors for COVID-19 mortality in older people. The symptomatology of COVID-19 indicates that lethal outcomes of infection rely on neurogenic mechanisms. The present review compiles the available knowledge pointing to the convergence of COVID-19 complications with the mechanisms of autonomic dysfunctions in AD and aging. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is prone to neuroinvasion from the lung along the vagus nerve up to the brainstem autonomic nervous centers involved in the coupling of cardiovascular and respiratory rhythms. The brainstem autonomic network allows SARS-CoV-2 to trigger a neurogenic switch to hypertension and hypoventilation, which may act in synergy with aging- and AD-induced dysautonomias, along with an inflammatory "storm". The lethal outcomes of COVID-19, like in AD and unhealthy aging, likely rely on a critical hypoactivity of the efferent vagus nerve cholinergic pathway, which is involved in lowering cardiovascular pressure and systemic inflammation tone. We further discuss the emerging evidence supporting the use of 1) the non-invasive stimulation of vagus nerve as an additional therapeutic approach for severe COVID-19, and 2) the demonstrated vagal tone index, i.e., heart rate variability, via smartphone-based applications as a non-serological low-cost diagnostic of COVID-19. These two well-known medical approaches are already available and now deserve large-scale testing on human cohorts in the context of both AD and COVID-19.

The Vagus Nerve in the Neuro-Immune Axis: Implications in the Pathology of the Gastrointestinal Tract.

The vagus nerve (VN) is the longest nerve of the organism and a major component of the parasympathetic nervous system which constitutes the autonomic nervous system (ANS), with the sympathetic nervous system. There is classically an equilibrium between the sympathetic and parasympathetic nervous systems which is responsible for the maintenance of homeostasis. An imbalance of the ANS is observed in various pathologic conditions. The VN, a mixed nerve with 4/5 afferent and 1/5 efferent fibers, is a key component of the neuro-immune and brain-gut axes through a bidirectional communication between the brain and the gastrointestinal (GI) tract. A dual anti-inflammatory role of the VN is observed using either vagal afferents, targeting the hypothalamic-pituitary-adrenal axis, or vagal efferents, targeting the cholinergic anti-inflammatory pathway. The sympathetic nervous system and the VN act in synergy, through the splenic nerve, to inhibit the release of tumor necrosis factor-alpha (TNFα) by macrophages of the peripheral tissues and the spleen. Because of its anti-inflammatory effect, the VN is a therapeutic target in the treatment of chronic inflammatory disorders where TNFα is a key component. In this review, we will focus on the anti-inflammatory role of the VN in inflammatory bowel diseases (IBD). The anti-inflammatory properties of the VN could be targeted pharmacologically, with enteral nutrition, by VN stimulation (VNS), with complementary medicines or by physical exercise. VNS is one of the alternative treatments for drug resistant epilepsy and depression and one might think that VNS could be used as a non-drug therapy to treat inflammatory disorders of the GI tract, such as IBD, irritable bowel syndrome, and postoperative ileus, which are all characterized by a blunted autonomic balance with a decreased vagal tone.

Congenital insensitivity to pain and anhidrosis: Case report and review of findings along neuro-immune axis in the disorder.

Congenital insensitivity to pain and anhidrosis (CIPA) is one of the hereditary autonomic and sensory neuropathies. Typically presenting in infancy, it manifests as hyperpyrexia from defects in sweating (autonomic) and self-mutilating injuries from pain insensitivity (sensory). CIPA being rare in North America, diagnosis is often missed due to variable presentation. Subsequent management of its complications is therefore delayed. We report an unusual presentation in a 2-year-old girl with preexisting diagnosis of CIPA who was evaluated for bilateral upper extremity paresis of insidious onset. MRI revealed a mass compressing her cervical spine as the cause, and work up suggested immune dysfunction as possible etiology. To our knowledge, this complication has not been reported before in association with the disease. We introduce the disease by explaining the molecular pathology behind its presenting features. The neurological findings, documented in association with CIPA, are summarized and serve as a reference for the various presentations of this rare disorder. Since this disease is known to affect the immune system, immune defects in CIPA are discussed with recommendations for surveillance of patient's immune status.

Potential therapeutic strategy to treat substance abuse related disorders.

The "Potential Therapeutic Strategy to Treat Substance Abuse Related Disorders" session was chaired by Dr. Sulie Chang, director of NeuroImmune Phamacology at Seton University. The four presenters (and their topics) were: Dr. Wen-zhe Ho (Miniway to stop HIV/HCV), Dr. Ru-Band Lu (Low dose of memantine in the treatment of opioid dependence in human), Dr. Ping Zhang (Treatment of alcohol-related disorders-Learning from stem/progenitor cell), and Chia-Hsiang Chen (Treatment of methamphetamine abuse: an antibody-based immunotherapy approach).