Mast cells: an expanding pathophysiological role from allergy to other disorders

Impact of Helicobacter pylori and metabolic syndrome on mast cell activation-related pathophysiology and neurodegeneration

Both Helicobacter pylori (H. pylori) infection and metabolic syndrome (MetS) are highly prevalent worldwide. The emergence of relevant research suggesting a pathogenic linkage between H. pylori infection and MetS-related cardio-cerebrovascular diseases and neurodegenerative disorders, particularly through mechanisms involving brain pericyte deficiency, hyperhomocysteinemia, hyperfibrinogenemia, elevated lipoprotein-a, galectin-3 overexpression, atrial fibrillation, and gut dysbiosis, has raised stimulating questions regarding their pathophysiology and its translational implications for clinicians. An additional stimulating aspect refers to H. pylori and MetS-related activation of innate immune cells, mast cells (MC), which is an important, often early, event in systemic inflammatory pathologies and related brain disorders. Synoptically, MC degranulation may play a role in the pathogenesis of H. pylori and MetS-related obesity, adipokine effects, dyslipidemia, diabetes mellitus, insulin resistance, arterial hypertension, vascular dysfunction and arterial stiffness, an early indicator of atherosclerosis associated with cardio-cerebrovascular and neurodegenerative disorders. Meningeal MC can be activated by triggers including stress and toxins resulting in vascular changes and neurodegeneration. Likewise, H.pylori and MetS-related MC activation is linked with: (a) vasculitis and thromboembolic events that increase the risk of cardio-cerebrovascular and neurodegenerative disorders, and (b) gut dysbiosis-associated neurodegeneration, whereas modulation of gut microbiota and MC activation may promote neuroprotection. This narrative review investigates the intricate relationship between H. pylori infection, MetS, MC activation, and their collective impact on pathophysiological processes linked to neurodegeneration. Through a comprehensive search of current literature, we elucidate the mechanisms through which H. pylori and MetS contribute to MC activation, subsequently triggering cascades of inflammatory responses. This highlights the role of MC as key mediators in the pathogenesis of cardio-cerebrovascular and neurodegenerative disorders, emphasizing their involvement in neuroinflammation, vascular dysfunction and, ultimately, neuronal damage. Although further research is warranted, we provide a novel perspective on the pathophysiology and management of brain disorders by exploring potential therapeutic strategies targeting H. pylori eradication, MetS management, and modulation of MC to mitigate neurodegeneration risk while promoting neuroprotection.

The Role of Helicobacter pylori and Metabolic Syndrome-Related Mast Cell Activation Pathologies and Their Potential Impact on Pregnancy and Neonatal Outcomes

Helicobacter pylori infection, a significant global burden beyond the gastrointestinal tract, has long been implicated in various systemic pathologies. Rising evidence suggests that the bacterium's intricate relationship with the immune system and its potential to induce chronic inflammation impact diverse pathophysiological processes in pregnant women that may in turn affect the incidence of several adverse pregnancy and neonate outcomes. Helicobacter pylori infection, which has been linked to metabolic syndrome and other disorders by provoking pericyte dysfunction, hyperhomocysteinemia, galectin-3, atrial fibrillation, gut dysbiosis, and mast cell activation pathologies, may also contribute to adverse pregnancy and neonatal outcomes. Together with increasing our biological understanding of the individual and collective involvement of Helicobacter pylori infection-related metabolic syndrome and concurrent activation of mast cells in maternal, fetus, and neonatal health outcomes, the present narrative review may foster related research endeavors to offer novel therapeutic approaches and informed clinical practice interventions to mitigate relevant risks of this critical topic among pregnant women and their offspring.

Correlating Salivary Levels of Immunoglobin E and Human Eosinophil Cationic Protein in the Aseer Cohort with Recurrent Apthous Stomatitis

Background

Repeated Aphthous Stomatitis (RAS) is the most prevalent inflammatory disorder of the oral mucosa, characterized by recurrent emergence of single or numerous painful ulcers. RAS usually affects healthy people without systemic illnesses. There is evidence linking atopy to the progression of this illness. Immunoglobulin E (IgE) and human eosinophil cationic protein (HECP) levels in the saliva of individuals with aphthous stomatitis were assessed as allergy-related indicators.

Materials and Methods

Sixty people were assessed for this study. 30 patients with RAS were included in the patient group, while 30 healthy individuals made up for the control group. Sixty participants' non-stimulated saliva was taken and IgE and HECP were evaluated using enzyme-linked immunosorbent assay (ELISA). Data were analyzed in SPSS 20 through the Mann-Whitney test and p<0.05 was considered significant.

Results

The salivary level of HECP was significantly (p 0.05) higher among cases (0.83 0.70) compared to controls (0.170 0.15), whereas the salivary level of IgE was not significantly (p = 0.41) higher among cases (35.60 11.19) compared to controls (67.42 18.34).

Conclusion

Even though this study found a positive correlation between elevated HECP levels and RAS, additional research with larger sample sizes is required to identify the biological mechanisms responsible for the observed associations and to include salivary HECP levels in the RAS patient's evaluation.

A model for irritable bowel syndrome and anxiety comorbidities in relation to alcohol use disorders

About 95% of human body serotonin synthesis occurs in the gastrointestinal tract (GI). Lack of sufficient serotonin levels is thought to play a key role in mood disorders, including anxiety disorders. In this study, we looked at a disorder affecting the GI tract, irritable bowel syndrome (IBS), and aimed to determine whether IBS is differentially associated with anxiety disorders in 252 chronic pain patients in the presence of a history of alcohol use disorders (AUD) given that alcohol is an extremely aggressive substance for the GI mucosa. We found that while the prevalence of IBS was not affected by the presence of AUD in chronic pain patients, IBS had significantly higher comorbidity with anxiety disorders in chronic pain patients with comorbid alcohol use disorders. We argue that these findings highlight mechanistic differences in the comorbidity of anxiety disorders with chronic pain and AUD, implicating a central role for GI problems stemming from chronic alcohol use. The findings may have important implications for the treatment of IBS patients with AUD who commonly present with anxiety disorders which could motivate the continuation of problematic drinking and impede recovery success. We propose that addressing GI problems in patients with AUD may help manage AUD and recovery more effectively.

Pathophysiological Involvement of Mast Cells and the Lipid Mediators in Pulmonary Vascular Remodeling

Mast cells are responsible for IgE-dependent allergic responses, but they also produce various bioactive mediators and contribute to the pathogenesis of various cardiovascular diseases, including pulmonary hypertension (PH). The importance of lipid mediators in the pathogenesis of PH has become evident in recent years, as exemplified by prostaglandin I2, the most central therapeutic target in pulmonary arterial hypertension. New bioactive lipids other than eicosanoids have also been identified that are associated with the pathogenesis of PH. However, it remains largely unknown how mast cell-derived lipid mediators are involved in pulmonary vascular remodeling. Recently, it has been demonstrated that mast cells produce epoxidized n-3 fatty acid (n-3 epoxides) in a degranulation-independent manner, and that n-3 epoxides produced by mast cells regulate the abnormal activation of pulmonary fibroblasts and suppress the progression of pulmonary vascular remodeling. This review summarizes the role of mast cells and bioactive lipids in the pathogenesis of PH. In addition, we introduce the pathophysiological role and therapeutic potential of n-3 epoxides, a mast cell-derived novel lipid mediator, in the pulmonary vascular remodeling in PH. Further knowledge of mast cells and lipid mediators is expected to lead to the development of innovative therapies targeting pulmonary vascular remodeling.

Effect of intravesical tarantula cubensis extract (Theranekron) on inflammation in an interstitial cystitis rat model

OBJECTIVES

To reveal the histopathological and immunological outcomes of intravesical treatment with tarantula cubensis extract (TCE) in a rat model of interstitial cystitis.

METHODS

A total of 30 female Wistar albino rats were divided into three groups: group 1 (control group), group 2 (disease group), and group 3 (treatment group). The rat model of interstitial cystitis was created by biweekly intraperitoneal administration of cyclophosphamide (CYP). In group 3, TCE (a venom extracted from a brown spider known as tarantula cubensis) was administered intravesically after the model had been created. Urothelial degeneration, necrosis, ulcer, bleeding, edema, inflammation and mast cell count, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), myeloperoxidase (MPO), and hydroxyproline parameters were evaluated. Statistical analysis was performed using one-way analysis of variance, chi-square tests, and Kruskal-Wallis tests.

RESULTS

All parameters were found to be lower in the rats in group 1 than in the other groups, and IL-6 and MPO values were found to be higher in group 2 (p < .001). The mean TNF-alpha value was highest in group 2 (p = .078). No difference was found between all groups regarding ulcer (p = .087). Urothelial degeneration, necrosis, edema, inflammation, hemorrhage and fibroblast proliferations, and hydroxyproline values were higher in group 3 (p < .001).

CONCLUSIONS

Intravesical TCE instillation produces an anti-inflammatory effect by reducing the levels of inflammatory parameters such as IL-6, TNF-alpha, and MPO in bladder tissue. It also accelerates tissue healing by increasing hydroxyproline and fibroblast proliferation.

Urinary Biomarkers in Interstitial Cystitis/Bladder Pain Syndrome and Its Impact on Therapeutic Outcome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is defined as a chronic bladder disorder with suprapubic pain (pelvic pain) and pressure and/or discomfort related to bladder filling accompanied by lower urinary tract symptoms, such as urinary frequency and urgency without urinary tract infection (UTI) lasting for at least 6 weeks. IC/BPS presents significant bladder pain and frequency urgency symptoms with unknown etiology, and it is without a widely accepted standard in diagnosis. Patients’ pathological features through cystoscopy and histologic features of bladder biopsy determine the presence or absence of Hunner lesions. IC/PBS is categorized into Hunner (ulcerative) type IC/BPS (HIC/BPS) or non-Hunner (nonulcerative) type IC/BPS (NHIC/BPS). The pathophysiology of IC/BPS is composed of multiple possible factors, such as chronic inflammation, autoimmune disorders, neurogenic hyperactivity, urothelial defects, abnormal angiogenesis, oxidative stress, and exogenous urine substances, which play a crucial role in the pathophysiology of IC/BPS. Abnormal expressions of several urine and serum specimens, including growth factor, methylhistamine, glycoprotein, chemokine and cytokines, might be useful as biomarkers for IC/BPS diagnosis. Further studies to identify the key molecules in IC/BPS will help to improve the efficacy of treatment and identify biomarkers of the disease. In this review, we discuss the potential medical therapy and assessment of therapeutic outcome with urinary biomarkers for IC/BPS.

Altered diversity and composition of gut microbiota in patients with allergic rhinitis

BACKGROUND

Recently, multiple studies have suggested an association between gut dysbiosis and allergic rhinitis (AR) development. However, the role of gut microbiota in AR development remains obscure.

METHODS

The goal of this study was to compare the gut microbiota composition and short-chain fatty acid (SCFAs) differences associated with AR (N = 18) and HCs (healthy controls, N = 17). Gut microbiota 16SrRNA gene sequences were analyzed based on next-generation sequencing. SCFAs in stool samples were analyzed by gas chromatography-mass spectrometry (GC-MS).

RESULTS

Compared with HCs, the gut microbiota composition of AR was significantly different in diversity and richness. At the phylum level, the abundance of Firmicutes in the AR group were significantly lower than those in the HCs group. At the genus level, the abundance of Blautia, Eubacterium_hallii_group, Romboutsia, Collinsella, Dorea, Subdoligranulum and Fusicatenibacter in the AR group were significantly lower than that in the HCs group. The concentrations of SCFAs were significantly lower in the AR group compared with the HCs group. Correlation analysis showed that the Eubacterium-hallii-group and Blautia correlated positively with SCFAs.

CONCLUSION

Our results demonstrate compositional and functional alterations of the gut microbiome in AR.

Chronic psychological stress and lower urinary tract symptoms

It is well established that lower urinary tract symptoms (LUTS), particularly urinary urgency and incontinence, cause stress and anxiety for patients. However, there is mounting evidence that the relationship between these two factors is bidirectional and that chronic psychological stress itself can result in the development of symptoms such as urinary frequency, urgency, incontinence, and pelvic pain. This review considers the evidence that such a relationship exists and reviews the literature from clinical and animal studies to identify some of the mechanisms that might be involved. Inflammatory responses induced by chronic stress appear to offer the strongest link to bladder dysfunction. There is overwhelming evidence, both in patients and animal models, for a release of pro-inflammatory cytokines and chemokines during periods of chronic stress. Furthermore, cytokines have been shown to cause bladder dysfunction and pain via actions in the central nervous system and locally in the bladder. In the brain and spinal cord, pro-inflammatory cytokines influence the regulation of micturition pathways by corticotropin-releasing factor (CRF) and its receptors, while peripherally cytokines affect bladder function, directly causing detrusor hypertrophy and afferent nerve hypersensitivity. There is little information on which treatments may have most benefit for stressed/anxious patients with LUTS, but animal studies suggest traditional drugs for overactive bladder (solifenacin, mirabegron) are more effective on LUTS than anxiolytic drugs (fluoxetine, imipramine). The preliminary preclinical data for CRF receptor antagonists is not consistent. A clearer understanding of the mechanisms involved in stress-induced LUTS should provide a basis for improved treatment of this condition.

Voluntary Wheel Running Partially Attenuates Early Life Stress-Induced Neuroimmune Measures in the Dura and Evoked Migraine-Like Behaviors in Female Mice

Migraine is a complex neurological disorder that affects three times more women than men and can be triggered by endogenous and exogenous factors. Stress is a common migraine trigger and exposure to early life stress increases the likelihood of developing chronic pain disorders later in life. Here, we used our neonatal maternal separation (NMS) model of early life stress to investigate whether female NMS mice have an increased susceptibility to evoked migraine-like behaviors and the potential therapeutic effect of voluntary wheel running. NMS was performed for 3 h/day during the first 3 weeks of life and initial observations were made at 12 weeks of age after voluntary wheel running (Exercise, -Ex) or sedentary behavior (-Sed) for 4 weeks. Mast cell degranulation rates were significantly higher in dura mater from NMS-Sed mice, compared to either naïve-Sed or NMS-Ex mice. Protease activated receptor 2 (PAR2) protein levels in the dura were significantly increased in NMS mice and a significant interaction of NMS and exercise was observed for transient receptor potential ankyrin 1 (TRPA1) protein levels in the dura. Behavioral assessments were performed on adult (>8 weeks of age) naïve and NMS mice that received free access to a running wheel beginning at 4 weeks of age. Facial grimace, paw mechanical withdrawal threshold, and light aversion were measured following direct application of inflammatory soup (IS) onto the dura or intraperitoneal (IP) nitroglycerin (NTG) injection. Dural IS resulted in a significant decrease in forepaw withdrawal threshold in all groups of mice, while exercise significantly increased grimace score across all groups. NTG significantly increased grimace score, particularly in exercised mice. A significant effect of NMS and a significant interaction effect of exercise and NMS were observed on hindpaw sensitivity following NTG injection. Significant light aversion was observed in NMS mice, regardless of exercise, following NTG. Finally, exercise significantly reduced calcitonin gene-related peptide (CGRP) protein level in the dura of NMS and naïve mice. Taken together, these findings suggest that while voluntary wheel running improved some measures in NMS mice that have been associated with increased migraine susceptibility, behavioral outcomes were not impacted or even worsened by exercise.

Human breast milk oligosaccharides attenuate necrotizing enterocolitis in rats by suppressing mast cell accumulation, DPPI activity and TLR4 expression in ileum tissue, and regulating mitochondrial damage of Caco-2 cells

Necrotizing enterocolitis (NEC), a devastating infant disease characterized by severe intestinal necrosis, its pathogenesis is poorly understood, but appears to be multifactorial and highly associated with immaturity of gastrointestinal tract and immature innate-immune system. Breast-milk is effective strategy to protect infants against NEC. This study is using a NEC rat model to investigate the pathological mechanism of NEC involved intestinal-damages, and the therapeutic mechanism of sialylated human milk oligosaccharides (SHMOs) on NEC rats; also using cell model to investigate the effects of SHMOs on colon-epithelial cells (Caco-2) in-vitro. Extraction and characterization of SHMOs from breast milk, establishment of a NEC rat model, histopathological analysis and mast cell accounting of the terminal ileum were taken; The levels of DPPI, TLR4, IL-6, TNF-α, MMP-2/9 and glutathione were measured using various methods. Caco-2 cells were pre-treated with SHMOs and cultured with LPS, histamine, chymase or DPPI, cell viabilities and mitochondrial membrane potential were examined; flow cytometry was used to detect cell cycle. The accumulation of mast cells was found in the ileum of NEC rats, but prohibited by SHMOs treatment; the increased levels of TLR4, DPPI, IL-6, TNF-α, MMP-2/9 in NEC ileum were suppressed by SHMOs in-vivo. SHMOs prevented Caco-2 cells from LPS, histamine, chymase induced damages by surviving cell viability, regulating G0/G1 and S phase in cell cycles, and increasing mitochondrial membrane potential. These findings provide a new insight into the pharmacological mechanism of SHMOs treatment for NEC and suggest that SHMOs needs well attention for therapeutic aims.

Do Mast Cells Have a Role in Tendon Healing and Inflammation?

Understanding the links between the tendon healing process, inflammatory mechanisms, and tendon homeostasis/pain after tissue damage is crucial in developing novel therapeutics for human tendon disorders. The inflammatory mechanisms that are operative in response to tendon injury are not fully understood, but it has been suggested that inflammation occurring in response to nerve signaling, i.e., neurogenic inflammation, has a pathogenic role. The mechanisms driving such neurogenic inflammation are presently not clear. However, it has recently been demonstrated that mast cells present within the injured tendon can express glutamate receptors, raising the possibility that mast cells may be sensitive to glutamate signaling and thereby modulate neurogenic inflammation following tissue injury. In this review, we discuss the role of mast cells in the communication with peripheral nerves, and their emerging role in tendon healing and inflammation after injury.

Interstitial cystitis/bladder pain syndrome: The evolving landscape, animal models and future perspectives

Interstitial cystitis/bladder pain syndrome is a debilitating condition of unknown etiology characterized by persistent pelvic pain with lower urinary tract symptoms and comprises a wide variety of potentially clinically useful phenotypes with different possible etiologies. Current clinicopathological and genomic evidence suggests that interstitial cystitis/bladder pain syndrome should be categorized by the presence or absence of Hunner lesions, rather than by clinical phenotyping based on symptomatology. The Hunner lesion subtype is a distinct inflammatory disease with proven bladder etiology characterized by epithelial denudation and enhanced immune responses frequently accompanied by clonal expansion of infiltrating B cells, with potential engagement of infection. Meanwhile, the non-Hunner lesion subtype is a non-inflammatory disorder with little evidence of bladder etiology. It is potentially associated with urothelial malfunction and neurophysiological dysfunction, and frequently presents with somatic and/or psychological symptoms, that commonly result in central nervous sensitization. Animal models of autoimmune cystitis and neurogenic sensitization might serve as disease models for the Hunner lesion and non-Hunner lesion subtypes, respectively. Here, we revisit the taxonomy of interstitial cystitis/bladder pain syndrome according to current research, and discuss its potential pathophysiology and representative animal models. Categorization of interstitial cystitis/bladder pain syndrome based on cystoscopy is mandatory to design optimized treatment and research strategies for each subtype. A tailored approach that specifically targets the characteristic inflammation and epithelial denudation for the Hunner lesion subtype, or the urothelial malfunction, sensitized/altered nervous system and psychosocial problems for the non-Hunner lesion subtype, is essential for better clinical management and research progress in this complex condition.

Assessment of salivary antioxidant status and immunoglobulin E in patients with geographic tongue

Objective:

One of the possible ways of changing human health might be through the oral mucosa. One of tongue disorders is geographic tongue (GT), which classic manifestation is an area of erythema, with atrophy of filiform papillae of the tongue, surrounded by a serpiginous, white, hyperkeratotic border. Saliva is a rich source of antioxidant and fulfills an important role in maintaining the normal function of the oral cavity. The purpose of the present study was to investigate the status of salivary antioxidant and immunoglobulin E in patients with GT and healthy people.

Materials and Methods:

In this case-control study, samples were gathered from high school students in three municipal regions of Kermanshah, Iran by using multistage random cluster sampling method. The samples included 30 patients with GT (15 men and 15 women with the mean age of 17.6 ± 0.72) and 30 healthy volunteers (15 men and 15 women with the mean age of 17.1 ± 0.61). Saliva samples were collected through standard method, and total antioxidant capacity (TAC), catalase (CAT), and salivary immunoglobulin E were measured.

Results:

In patients with GT, unstimulated salivary shows increased level of immunoglobulin compared with that of control group (P = 0.013). However, there was no significant relationship between control and GT patient groups regarding TAC of saliva (P = 0.91) and CAT (P = 0.83).

Conclusion:

It seems that the activity of CAT enzyme and TAC of saliva does not play primary role in the pathogenesis of GT. However, the level of immunoglobulin E present in saliva can function as an indicator of increased sensitivity in GT.

Paradigm Shifts in Mast Cell and Basophil Biology and Function: An Emerging View of Immune Regulation in Health and Disease

The physiological role of the mast cell and basophil has for many years remained enigmatic. In this chapter, we briefly summarize some of the more recent studies that shed new light on the role of mast cells and basophils in health and disease. What we gain from these studies is a new appreciation for mast cells and basophils as sentinels in host defense and a further understanding that dysregulation of mast cell and basophil function can be a component of various diseases other than allergies. Perhaps the most important insight reaped from this work is the increasing awareness that mast cells and basophils can function as immunoregulatory cells that modulate the immune response in health and disease. Collectively, the recent knowledge provides new challenges and opportunities toward the development of novel therapeutic strategies to augment host protection and modify disease through manipulation of mast cell and basophil function.

Proteomic Analysis of Lipid Rafts from RBL-2H3 Mast Cells

Lipid rafts are highly ordered membrane microdomains enriched in cholesterol, glycosphingolipids, and certain proteins. They are involved in the regulation of cellular processes in diverse cell types, including mast cells (MCs). The MC lipid raft protein composition was assessed using qualitative mass spectrometric characterization of the proteome from detergent-resistant membrane fractions from RBL-2H3 MCs. Using two different post-isolation treatment methods, a total of 949 lipid raft associated proteins were identified. The majority of these MC lipid raft proteins had already been described in the RaftProtV2 database and are among highest cited/experimentally validated lipid raft proteins. Additionally, more than half of the identified proteins had lipid modifications and/or transmembrane domains. Classification of identified proteins into functional categories showed that the proteins were associated with cellular membrane compartments, and with some biological and molecular functions, such as regulation, localization, binding, catalytic activity, and response to stimulus. Furthermore, functional enrichment analysis demonstrated an intimate involvement of identified proteins with various aspects of MC biological processes, especially those related to regulated secretion, organization/stabilization of macromolecules complexes, and signal transduction. This study represents the first comprehensive proteomic profile of MC lipid rafts and provides additional information to elucidate immunoregulatory functions coordinated by raft proteins in MCs.

Adipocytokines leptin and adiponectin function as mast cell activity modulators

A growing body of data indicates that adipocytokines, including leptin and adiponectin, are critical components not only of metabolic regulation but also of the immune system, mainly by influencing the activity of cells participating in immunological and inflammatory processes. As mast cells (MCs) are the key players in the course of those mechanisms, this study aimed to evaluate the impact of leptin and adiponectin on some aspects of MC activity. We documented that in vivo differentiated mature tissue MCs from the rat peritoneal cavity express a receptor for leptin (OB-R), as well as receptors for adiponectin (AdipoR1 and AdipoR2). We established that leptin, but not adiponectin, stimulates MCs to release of histamine as well as to generation of cysteinyl leukotrienes (cysLTs) and chemokine CCL2. We also found that both adipocytokines affect mRNA expression of various cytokines/chemokines. Leptin and adiponectin also activate MCs to produce reactive oxygen species. Moreover, we documented that leptin significantly augments the surface expression of receptors for cysLTs, i.e. CYSLTR1, CYSLTR2, and GPR17 on MCs, while adiponectin increases only GPR17 expression, and decreases CYSLTR2. Finally, we showed that both adipocytokines serve as potent chemoattractants for MCs. In intracellular signaling in MCs activated by leptin Janus-activated kinase 2, phospholipase C, phosphatidylinositol 3-kinase (PI3K), extracellular signal-regulated kinase (ERK1/2), and p38 molecules play a part whereas the adiponectin-induced activity of MCs is mediated through PI3K, p38, and ERK1/2 pathways. Our observations that leptin and adiponectin regulate MC activity might indicate that adipocytokines modulate the different processes in which MCs are involved.

Proteoglycans involved in bidirectional communication between mast cells and hippocampal neurons

BACKGROUND

Mast cells (MCs) in the brain can respond to environmental cues and relay signals to neurons that may directly influence neuronal electrical activity, calcium signaling, and neurotransmission. MCs also express receptors for neurotransmitters and consequently can be activated by them. Here, we developed a coculture model of peritoneal MCs, incubated together with dissociated hippocampal neurons for the study of cellular mechanisms involved in the mast cell-neuron interactions.

METHODS

Calcium imaging was used to simultaneously record changes in intracellular calcium [Ca2+]i in neurons and MCs. To provide insight into the contribution of MCs on neurotransmitter release in rat hippocampal neurons, we used analysis of FM dye release, evoked by a cocktail of mediators from MCs stimulated by heat.

RESULTS

Bidirectional communication is set up between MCs and hippocampal neurons. Neuronal depolarization caused intracellular calcium [Ca2+]i oscillations in MCs that produced a quick response in neurons. Furthermore, activation of MCs with antigen or the secretagogue compound 48/80 also resulted in a neuronal [Ca2+]i response. Moreover, local application onto neurons of the MC mediator cocktail elicited Ca2+ transients and a synaptic release associated with FM dye destaining. Neuronal response was partially blocked by D-APV, a N-methyl-D-aspartate receptor (NMDAR) antagonist, and was inhibited when the cocktail was pre-digested with chondroitinase ABC, which induces enzymatic removal of proteoglycans of chondroitin sulfate (CS).

CONCLUSIONS

MC-hippocampal neuron interaction affects neuronal [Ca2+]i and exocytosis signaling through a NMDAR-dependent mechanism.

Structure-based virtual screening for novel chymase inhibitors by in silico fragment mapping

The term chymase refers to a family of chymotrypsin-like serine proteases stored within the secretory granules of mast cells. Recently, a variety of small molecule inhibitors for chymase have been developed with a primary focus on the treatment of cardiovascular diseases. Despite the expected therapeutic benefit of these chymase inhibitors, they have not been used clinically. Here, we attempted to identify new chymase inhibitors using a multistep structure-based virtual screening protocol combined with our knowledge-based in silico fragment mapping technique. The mapping procedure identified fragments with novel modes of interaction at the oxyanion hole of chymase. Next, we constructed a three-dimensional (3D) pharmacophore model and retrieved eight candidate chymase inhibitors from a commercial database that included approximately five million compounds. This selection was achieved using a multistep virtual screening protocol, which combined a 3D pharmacophore-based search, docking calculations, and analyses of binding free energy. One of the eight compounds exhibited concentration-dependent chymase inhibitory activity, which could be further optimized to develop more potent chymase inhibitors.

Fermented red ginseng and ginsenoside Rd alleviate ovalbumin-induced allergic rhinitis in mice by suppressing IgE, interleukin-4, and interleukin-5 expression

Background

To increase the pharmacological effects of red ginseng (RG, the steamed root of Panax ginseng Meyer), RG products modified by heat process or fermentation have been developed. However, the antiallergic effects of RG and modified/fermented RG have not been simultaneously examined. Therefore, we examined the allergic rhinitis (AR)-inhibitory effects of water-extracted RG (wRG), 50% ethanol-extracted RG (eRG), and bifidobacteria-fermented eRG (fRG) in vivo.

Methods

RBL-2H3 cells were stimulated with phorbol 12-myristate-13-acetate/A23187. Mice with AR were prepared by treatment with ovalbumin. Allergic markers IgE, tumor necrosis factor-α, interleukin (IL)-4, and IL-5 were assayed in the blood, bronchoalveolar lavage fluid, nasal mucosa, and colon using enzyme-linked immunosorbent assay. Mast cells, eosinophils, and Th2 cell populations were assayed using a flow cytometer.

Results

RG products potently inhibited IL-4 expression in phorbol 12-myristate-13-acetate/A23187-stimulated RBL-2H3 cells. Of tested RG products, fRG most potently inhibited IL-4 expression. RG products also alleviated ovalbumin-induced AR in mice. Of these, fRG most potently reduced nasal allergy symptoms and blood IgE levels. fRG treatment also reduced IL-4 and IL-5 levels in bronchoalveolar lavage fluid, nasal mucosa, and reduced mast cells, eosinophils, and Th2 cell populations. Furthermore, treatment with fRG reduced IL-4, IL-5, and IL-13 levels in the colon and restored ovalbumin-suppressed Bacteroidetes and Actinobacteria populations and ovalbumin-induced Firmicutes population in gut microbiota. Treatment with ginsenoside Rd significantly alleviated ovalbumin-induced AR in mice.

Conclusion

fRG and ginsenoside Rd may alleviate AR by suppressing IgE, IL-4, IL-5, and IL-13 expression and restoring the composition of gut microbiota.

Bifidobacterium longum IM55 and Lactobacillus plantarum IM76 alleviate allergic rhinitis in mice by restoring Th2/Treg imbalance and gut microbiota disturbance

This study aimed to examine whether probiotics, which suppressed the differentiation of splenic T cells into type 2 helper T (Th2) cells and induced into regulatory T cells in vitro, alleviate allergic rhinitis (AR) and gut microbiota disturbance. We isolated Bifidobacterium longum IM55 and Lactobacillus plantarum IM76 from human faecal microbiota and kimchi, respectively, and examined their effects on ovalbumin (OVA)-induced AR and gut microbiota disturbance in mice. Treatment with IM55, IM76, or their probiotic mixture (PM) significantly reduced OVA-induced allergic nasal symptoms and blood immunoglobulin E (IgE) levels in mice. These also reduced OVA-induced interleukin (IL)-4 and IL-5 levels in nasal tissues and bronchoalveolar lavage fluid (BALF) but increased OVA-suppressed IL-10 levels. Treatment with IM55, IM76, or PM reduced OVA-induced increase in the populations of mast cells, eosinophils, and Th2 cells and increased OVA-suppressed population of regulatory T cells in the BALF. Treatment with IM55, IM76, or PM also inhibited OVA-induced expression of IL-5 in lung and colon tissues and restored OVA-disturbed composition of gut microbiota Proteobacteria, Bacteroidetes, and Actinobacteria. These results suggest that IM55 and IM67 can alleviate AR by restoring Th2/Treg imbalance and gut microbiota disturbance.

Leptin stimulates tissue rat mast cell pro-inflammatory activity and migratory response

Objective

The aim of this study was to determine whether leptin, a member of the adipocytokines involved in immune and inflammatory response regulation, may influence some aspects of mast cell biology.

Materials and methods

Experiments were done in vitro on fully mature tissue rat mast cells isolated from the peritoneal cavity, and leptin was used at concentrations 0.001–100 ng/ml. The effect of leptin on mast cell degranulation (histamine release assay), intracellular Ca²⁺ level (fluorimetry), pro-inflammatory mediator release (ELISA technique), surface receptor expression (flow cytometry and confocal microscopy), and migration (Boyden microchamber assay) was estimated.

Results

Leptin was found to stimulate mast cells to degranulation and histamine release. It induced the intracellular Ca²⁺ increase, as well. In response to leptin stimulation, mast cells generated and released cysLTs and chemokine CCL3. Leptin-induced upregulation of CYSLTR1 and CYSLTR2 surface expression was observed. Moreover, this adipocytokine stimulated mast cells to migratory response, even in the absence of extracellular matrix (ECM) proteins.

Conclusions

Our observations clearly documented that leptin promotes the pro-inflammatory activity of mast cells, and it thereby engages these cells in the inflammatory processes.

Association between Serum Immnunoglobulin E and Pterygium: A Population-Based Study from South Korea

PURPOSE

Several studies have shown that pterygium is associated with inflammation, angiogenesis, and fibrosis. However, it should be acknowledged that not enough is known about the association between immunoglobulin E (IgE) and pterygium. The present study was conducted to test the hypothesis that elevated serum IgE is associated with a greater prevalence of pterygium.

MATERIAL AND METHODS

A cross-sectional study was performed using data of 1,548 participants aged 30 years or older who were enrolled in the Korea National Health and Nutrition Examination Survey conducted in 2010. Multivariable logistic regression analysis was used to examine the relationship between pterygium and allergic conditions, including total serum IgE and allergen-specific serum IgE levels, after adjusting for potential confounding factors.

RESULTS

Participants with pterygium were more likely have increased IgE level (p = 0.009). After adjusting for potential confounders, the odds ratio (OR) for pterygium was greater in participants with higher total serum IgE levels (OR = 1.63; p = 0.047). Multivariable-adjusted ORs of pterygium across the tertile of increasing IgE were 1.00 (reference), 1.18, and 1.45, (P for linear trend = 0.038). Although the ORs for the upper two tertiles of cockroach and dog allergen-specific IgE were higher than those for the lowest tertile, allergen-specific serum IgE showed no clear association with pterygium.

CONCLUSIONS

Increased total serum IgE concentration is independently related to pterygium after adjusting for confounding factors. To the best of our knowledge, this study is the first research that reveals an association between serum IgE and pterygium.

Frequencies of abnormal humoral and cellular immune component levels in peripheral blood of patients with recurrent aphthous ulceration

BACKGROUND/PURPOSE

Recurrent aphthous ulceration (RAU) has an incidence of approximately 20% in general population. However, its exact cause remains unknown. Increasing evidence suggests that immunologic mechanisms may play crucial roles in the etiology of this disease.

MATERIALS AND METHODS

The peripheral blood samples were obtained from 85 patients with RAU during acute phase and 87 healthy controls. The serum levels of IgG, IgA, IgM, C3 and C4 were measured by immunoturbidimetry. In addition, the serum IgE levels were measured by electro-chemiluminescence immunoassay. Furthermore, the percentages of B, T, CD4+ T, CD8+ T lymphocytes and natural killer (NK) cells in peripheral blood were determined by flow cytometry.

RESULTS

Our findings showed that the serum IgG, IgA, IgE, C3 and C4 levels of RAU patients were significantly higher than those of healthy controls. The percentages of CD4+ T cells and B cells in peripheral blood of RAU patients were significantly decreased, whereas the percentages of CD8+ T cells and NK cells of RAU patients were remarkably increased. Our results indicated that the IgG level was elevated in 18 patients (21.2%) and that the IgE level was increased in 21 patients (24.7%). Our results also showed that the frequency of abnormal IgG or IgE levels were significantly correlated with that of abnormal CD8+ T cell percentage in RAU patients.

CONCLUSION

The levels of both humoral and cellular immune components could be altered in RAU. The relationship between humoral and cellular immune may be potentially important immunologic aspects involved in the pathogenesis of RAU.

Sensitization of C-fiber nociceptors in mice with sickle cell disease is decreased by local inhibition of anandamide hydrolysis

Chronic pain and hyperalgesia, as well as pain resulting from episodes of vaso-occlusion, are characteristic features of sickle cell disease (SCD) and are difficult to treat. Since there is growing evidence that increasing local levels of endocannabinoids can decrease hyperalgesia, we examined the effects of URB597, a fatty acid amide hydrolase (FAAH) inhibitor, which blocks the hydrolysis of the endogenous cannabinoid anandamide, on hyperalgesia and sensitization of cutaneous nociceptors in a humanized mouse model of SCD. Using homozygous HbSS-BERK sickle mice, we determined the effects of URB597 on mechanical hyperalgesia and on sensitization of C-fiber nociceptors in vivo. Intraplantar administration of URB597 (10 μg in 10 μL) decreased the frequency of withdrawal responses evoked by a von Frey monofilament (3.9 mN bending force) applied to the plantar hind paw. This was blocked by the CB1 receptor antagonist AM281 but not by the CB2 receptor antagonist AM630. Also, URB597 decreased hyperalgesia in HbSS-BERK/CB2R sickle mice, further confirming the role of CB1 receptors in the effects produced by URB597. Electrophysiological recordings were made from primary afferent fibers of the tibial nerve in anesthetized mice. The proportion of Aδ- and C-fiber nociceptors that exhibited spontaneous activity and responses of C-fibers to mechanical and thermal stimuli were greater in HbSS-BERK sickle mice as compared to control HbAA-BERK mice. Spontaneous activity and evoked responses of nociceptors were decreased by URB597 via CB1 receptors. It is suggested that enhanced endocannabinoid activity in the periphery may be beneficial in alleviating chronic pain associated with SCD.

Mast cell deficiency attenuates acupuncture analgesia for mechanical pain using c-kit gene mutant rats

Background

Acupuncture therapy plays a pivotal role in pain relief, and increasing evidence demonstrates that mast cells (MCs) may mediate acupuncture analgesia. The present study aims to investigate the role of MCs in acupuncture analgesia using c-kit gene mutant-induced MC-deficient rats.

Materials and methods

WsRC-Ws/Ws rats and their wild-type (WT) littermates (WsRC-+/+) were used. The number of MCs in skin of ST36 area was compared in two rats after immunofluorescence labeling. Mechanical withdrawal latency (MWL), mechanical withdrawal threshold (MWT), and thermal withdrawal latency (TWL) were measured on bilateral plantar for pain threshold evaluation before and after each stimulus. Acupuncture- and moxibustion-like stimuli (43°C, 46°C heat, 1 mA electroacupuncture [EA], 3 mA EA, and manual acupuncture [MA]) were applied randomly on different days.

Results

Fewer MCs were observed in the skin of ST36 in mutant rats compared to WT rats (P<0.001). For pain thresholds, MWL and MWT were higher in WsRC-Ws/Ws compared to WsRC-+/+ on bilateral paws (P<0.05), but TWL was not different between the two rats (P>0.05). Bilateral MWL and MWT in WsRC-+/+ rats increased significantly after each stimulus compared to baseline (P<0.01, P<0.001). In WsRC-Ws/Ws rats, only noxious stimuli could produce anti-nociceptive effects for mechanical pain (46°C, 3 mA EA, MA) (P<0.01, P<0.001). Additionally, the net increases in MWL and MWT induced by most stimuli were greater in WT than in mutant rats (P<0.05). For thermal nociception, either high- or low-intensity stimuli could significantly augment TWL in two rats (P<0.001), and the net increases of TWL evoked by most stimuli were to the same extent in two genetic variants.

Conclusion

MCs influence the basic mechanical but not thermal pain threshold. MCs participate in acupuncture analgesia in mechanical but not in thermal nociception, in that MC deficiency may attenuate the mechanical analgesia evoked by high-intensity stimuli and eliminate analgesia provoked by low-intensity stimuli.

Mast cells in neuropathic pain: an increasing spectrum of their involvement in pathophysiology

Mast cells are immunological cells that are diversely distributed in different parts of the body. Their role in various pathological conditions such as hypersensitivity, atherosclerosis, pulmonary hypertension, and male infertility has been reported by different scientists. Apart from these, a number of studies have shown their important role in pathogenesis of neuropathic pain of diverse aetiology. They have been found to release active mediators, primarily histamine and serotonin on degranulation in response to different stimuli including chemical, nerve damage, toxin or disease-related conditions. The mast cells stabilizer has shown pain attenuating effects by preventing degranulation of mast cells. Similarly, compound 48/80 (first dose 200 μg/100 g and after 6-h interval, second dose of 500 μg/100 g) caused the degranulation of the accumulated endoneurial histamine and 5-HT antagonists have shown pain relieving effects by attenuating the effects of histamine and serotonin, respectively. On the other hand, the mast cell degranulator compound 48/80 has shown dual action depending on its time of administration. The present review discusses the critical role of mast cells in the generation and maintenance of neuropathic pain in experimental models.

Role of Mast Cells in the Pathogenesis of Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is a neurological autoimmune disorder of the central nervous system (CNS), characterized by recurrent episodes of inflammatory demyelination and consequent axonal deterioration. The hallmark of the disease is the demyelinated plaque, a hypocellular area characterized by formation of astrocytic scars and infiltration of mononuclear cells. Recent studies have revealed that both innate and adaptive immune cells contribute to the pathogenesis of MS and its experimental autoimmune encephalomyelitis (EAE) model. Here, we review the current understanding of the role of mast cells in the pathogenesis of MS and EAE. Mast cells may act at the early stage that promote demyelination through interactions among mast cells, neurons, and other immune cells to mediate neuroinflammation. Studies from EAE model suggest that mast cells regulate adaptive autoimmune responses, present myelin antigens to T cells, disrupt the blood-brain barrier, and permit the entry of inflammatory cells and mediators into the CNS. Depletion or limiting mast cells could be a new promising therapeutic target for MS and EAE.

Potential Mechanisms Underlying Centralized Pain and Emerging Therapeutic Interventions

Centralized pain syndromes are associated with changes within the central nervous system that amplify peripheral input and/or generate the perception of pain in the absence of a noxious stimulus. Examples of idiopathic functional disorders that are often categorized as centralized pain syndromes include fibromyalgia, chronic pelvic pain syndromes, migraine, and temporomandibular disorder. Patients often suffer from widespread pain, associated with more than one specific syndrome, and report fatigue, mood and sleep disturbances, and poor quality of life. The high degree of symptom comorbidity and a lack of definitive underlying etiology make these syndromes notoriously difficult to treat. The main purpose of this review article is to discuss potential mechanisms of centrally-driven pain amplification and how they may contribute to increased comorbidity, poorer pain outcomes, and decreased quality of life in patients diagnosed with centralized pain syndromes, as well as discuss emerging non-pharmacological therapies that improve symptomology associated with these syndromes. Abnormal regulation and output of the hypothalamic-pituitary-adrenal (HPA) axis is commonly associated with centralized pain disorders. The HPA axis is the primary stress response system and its activation results in downstream production of cortisol and a dampening of the immune response. Patients with centralized pain syndromes often present with hyper- or hypocortisolism and evidence of altered downstream signaling from the HPA axis including increased Mast cell (MC) infiltration and activation, which can lead to sensitization of nearby nociceptive afferents. Increased peripheral input via nociceptor activation can lead to “hyperalgesic priming” and/or “wind-up” and eventually to central sensitization through long term potentiation in the central nervous system. Other evidence of central modifications has been observed through brain imaging studies of functional connectivity and magnetic resonance spectroscopy and are shown to contribute to the widespreadness of pain and poor mood in patients with fibromyalgia and chronic urological pain. Non-pharmacological therapeutics, including exercise and cognitive behavioral therapy (CBT), have shown great promise in treating symptoms of centralized pain.

The Influence of Early Life Experience on Visceral Pain

Pain is the most reported and troublesome symptom of nearly all functional disorders affecting the genitourinary and gastrointestinal organs. Patients with irritable bowel syndrome (IBS), interstitial cystitis/painful bladder syndrome (IC/PBS), vulvodynia, and/or chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS; collectively termed chronic pelvic pain syndromes) report pain severe enough to impact quality of life and often suffer from symptoms of or are diagnosed with more than one of these syndromes. This increased comorbidity between chronic pelvic pain syndromes, and with pain disorders of disparate body regions, as well as with mood disorders, can be influenced by disruptions in the hypothalamic-pituitary-adrenal (HPA) axis, which regulates the response to stress and influences the perception of pain. Experiencing trauma, neglect, or abuse in early life can permanently affect the functioning of the HPA axis. As such, a significant proportion of patients suffering from comorbid chronic pelvic pain syndromes report a history of early life stress or trauma. Here we will report on how these early life experiences influence chronic pelvic pain in patients. We will also discuss various rodent models that have been developed to study this phenomenon to understand the mechanisms underlying HPA axis dysfunction, as well as potential underlying mechanisms connecting these syndromes to one another.

Increased mast cell degranulation and co-localization of mast cells with the NMDA receptor-1 during healing after Achilles tendon rupture

The role of inflammation and the mechanism of tendon healing after rupture has historically been a matter of controversy. The purpose of the present study is to investigate the role of mast cells and their relation to the NMDA receptor-1 (a glutamate receptor) during healing after Achilles tendon rupture. Eight female Sprague Dawley rats had their right Achilles tendon transected. Three weeks after rupture, histological quantification of mast cell numbers and their state of degranulation was assessed by histochemistry. Co-localization of mast cell tryptase (a mast cell marker) and NMDA receptor-1 was determined by immunofluorescence. The intact left Achilles tendon was used as control. An increased number of mast cells and a higher proportion of degranulated mast cells were found in the healing Achilles tendon compared to the intact. In addition, increased co-localization of mast cell tryptase and NMDA receptor-1 was seen in the areas of myotendinous junction, mid-tendon proper and bone tendon junction of the healing versus the intact tendon. These findings introduce a possible role for mast cells in the healing phase after Achilles tendon rupture.

Pharmacological investigations on mast cell stabilizer and histamine receptor antagonists in vincristine-induced neuropathic pain

The present study was designed to investigate the role of mast cells and mast cell-derived histamine in vincristine-induced neuropathic pain. Neuropathic pain was induced by administration of vincristine (100 μg/kg, i.p.) over a period of 10 days, with a break of 2 days, and pain behavioural estimations including pin prick, hot plate and acetone spray tests were performed to assess mechanical and heat hyperalgesia and cold allodynia, respectively, on days 0, 14 and 28. Mast cell stabilizer, sodium cromoglycate, H₁ receptor antagonist promethazine and H₂ receptor antagonist ranitidine were administered over a period of 12 days. Administration of vincristine resulted in significant development of heat and mechanical hyperalgesia as well as cold allodynia. Furthermore, the pain observed was markedly elevated on the 28th day in comparison to the 14th day. Administration of sodium cromoglycate, promethazine and ranitidine significantly reduced mechanical and heat hyperalgesia and cold allodynia. However, the pain-attenuating effects of ranitidine were significantly less as compared to sodium cromoglycate and promethazine, which suggests that H₁ receptors play a more important role than H₂ receptors in vincristine-induced neuropathic pain. It may be concluded that vincristine may degranulate mast cells to release inflammatory mediators, particularly histamine which may act through H₁ (primarily H₁) and H₂ receptors to induce neuropathic pain.

Peripheral inflammatory pain sensitisation is independent of mast cell activation in male mice

The immune and sensory systems are known for their close proximity and interaction. Indeed, in a variety of pain states, a myriad of different immune cells are activated and recruited, playing a key role in neuronal sensitisation. During inflammatory pain it is thought that mast cells (MC) are one of the immune cell types involved in this process, but so far the evidence outlining their direct effect on neuronal cells remains unclear. To clarify whether MC are involved in inflammatory pain states, we used a transgenic mouse line (Mctp5Cre-iDTR) in which MC could be depleted in an inducible manner by administration of diphtheria toxin. Our results show that ablation of MC in male mice did not result in any change in mechanical and thermal hypersensitivity in the CFA model of inflammatory pain. Similarly, edema and temperature triggered by CFA inflammation at the injection site remained identical in MC depleted mice compared with their littermate controls. In addition, we show that Mctp5Cre-iDTR mice display normal levels of mechanical hypersensitivity after local injection of nerve growth factor (NGF), a factor well characterised to produce peripheral sensitisation and for being upregulated upon injury and inflammation. We also demonstrate that NGF treatment in vitro does not lead to an increased level of tumor necrosis factor-α in bone marrow-derived MC. Furthermore, our qRT-PCR data reveal that MC express negligible levels of NGF receptors, thereby explaining the lack of response to NGF. Together, our data suggest that MC do not play a direct role in peripheral sensitisation during inflammatory conditions.

Mast cells: new therapeutic target in helminth immune modulation

Helminth infection and their secreted antigens have a protective role in many immune-mediated inflammatory disorders such as inflammatory bowel disease, rheumatoid arthritis and multiple sclerosis. However, studies have focused primarily on identifying immune protective mechanisms of helminth infection and their secreted molecules on dendritic cells and macrophages. Given that mast cells have been shown to be implicated in the pathogenesis and progression of many inflammatory disorders, their role should also be examined and considered as cellular target for helminth-based therapies. As there is a dearth of studies examining the interaction of helminth-derived antigens and mast cells, this review will focus on the role of mast cells during helminth infection and examine our current understanding of the involvement of mast cells in TH 1/TH 17-mediated immune disorders. In this context, potential mechanisms by which helminths could target the TH 1/TH 17 promoting properties of mast cells can be identified to unveil novel therapeutic mast cell driven targets in combating these inflammatory disorders.

Pharmacological treatment options for mast cell activation disease

Mast cell activation disease (MCAD) is a term referring to a heterogeneous group of disorders characterized by aberrant release of variable subsets of mast cell (MC) mediators together with accumulation of either morphologically altered and immunohistochemically identifiable mutated MCs due to MC proliferation (systemic mastocytosis [SM] and MC leukemia [MCL]) or morphologically ordinary MCs due to decreased apoptosis (MC activation syndrome [MCAS] and well-differentiated SM). Clinical signs and symptoms in MCAD vary depending on disease subtype and result from excessive mediator release by MCs and, in aggressive forms, from organ failure related to MC infiltration. In most cases, treatment of MCAD is directed primarily at controlling the symptoms associated with MC mediator release. In advanced forms, such as aggressive SM and MCL, agents targeting MC proliferation such as kinase inhibitors may be provided. Targeted therapies aimed at blocking mutant protein variants and/or downstream signaling pathways are currently being developed. Other targets, such as specific surface antigens expressed on neoplastic MCs, might be considered for the development of future therapies. Since clinicians are often underprepared to evaluate, diagnose, and effectively treat this clinically heterogeneous disease, we seek to familiarize clinicians with MCAD and review current and future treatment approaches.

Mast Cell-Mediated Mechanisms of Nociception

Mast cells are tissue-resident immune cells that release immuno-modulators, chemo-attractants, vasoactive compounds, neuropeptides and growth factors in response to allergens and pathogens constituting a first line of host defense. The neuroimmune interface of immune cells modulating synaptic responses has been of increasing interest, and mast cells have been proposed as key players in orchestrating inflammation-associated pain pathobiology due to their proximity to both vasculature and nerve fibers. Molecular underpinnings of mast cell-mediated pain can be disease-specific. Understanding such mechanisms is critical for developing disease-specific targeted therapeutics to improve analgesic outcomes. We review molecular mechanisms that may contribute to nociception in a disease-specific manner.

Oxidative stress parameters and serum magnesium levels in patients with seasonal allergic conjunctivitis

OBJECTIVE

To evaluate oxidative stress parameters and serum magnesium (Mg) levels in patients with seasonal allergic conjunctivitis (SAC) during the pollen season.

METHODS

This observational cross-sectional study involved 35 patients with SAC without any other ocular and systemic diseases, and 38 consecutive, age- and sex-matched healthy subjects. Serum malondialdehyde (MDA), adjusted ischemia modified albumin (IMA), and Mg levels were quantified, and the results were compared between the groups.

RESULTS

No significant differences were found between the groups with respect to age (p = 0.416) and sex (p = 0.362). Serum MDA and adjusted IMA levels of the subjects with SAC (69.54 ± 7.71 μM and 0.74 ± 0.39 ABSU) were significantly higher than the control group (64.61 ± 5.89 μM and 0.57 ± 0.19 ABSU) (p = 0.002 and p = 0.025, respectively). There was no significant difference for serum Mg levels between the groups (p = 0.177).

CONCLUSION

We demonstrated higher levels of oxidative stress parameters in patients with SAC compared to the control group, which imply a possible role of oxidative stress in the pathogenesis of SAC.

Immune attack: the role of inflammation in Alzheimer disease

The past two decades of research into the pathogenesis of Alzheimer disease (AD) have been driven largely by the amyloid hypothesis; the neuroinflammation that is associated with AD has been assumed to be merely a response to pathophysiological events. However, new data from preclinical and clinical studies have established that immune system-mediated actions in fact contribute to and drive AD pathogenesis. These insights have suggested both novel and well-defined potential therapeutic targets for AD, including microglia and several cytokines. In addition, as inflammation in AD primarily concerns the innate immune system - unlike in 'typical' neuroinflammatory diseases such as multiple sclerosis and encephalitides - the concept of neuroinflammation in AD may need refinement.

Paradigm shifts in mast cell and basophil biology and function: an emerging view of immune regulation in health and disease

The physiological role of the mast cell and basophil has for many years remained enigmatic. In this chapter we briefly summarize some of the more recent studies that shed new light on the role of mast cells and basophils in health and disease. What we gain from these studies is a new appreciation for mast cells and basophils as sentinels in host defense and a further understanding that dysregulation of mast cell and basophil function can be a component of various diseases other than allergies. Perhaps, the most important insight reaped from this work is the increasing awareness that mast cells and basophils can function as immunoregulatory cells that modulate the immune response in health and disease. Collectively, the recent knowledge provides new challenges and opportunities towards the development of novel therapeutic strategies to augment host protection and modify disease through manipulation of mast cell and basophil function.

Role of mast cells in atherosclerosis: a classical inflammatory disease

Atherosclerosis is an inflammatory disease and hyperlipidaemia is one of the main risk factors for aging, hypertension and diabetes. Variance in plasma LDL cholesterol concentration may be associated with differences in cardiovascular disease risk and high levels of lipids are associated with increased risk of developing atherosclerosis. Macrophages, which generate pro-inflammatory cytokines, mainly interleukin-1 (IL-1) and tumor necrosis factor-α (TNF-alpha), are deeply involved in atherosclerosis, as well as mast cells which generate several cytokines, including IL-6 and IFN-gamma, and chemokines such as eotaxin, MCP-1 and RANTES involved in monocyte recruitment and differentiation in the arterial wall. In addition, mast cells participate in lipid retention and vascular cell remodeling, and are mediators of innate and adaptive immunity during atherosclerosis. Mast cells which accumulate in the human arterial intima and adventitia during atherosclerotic plaque progression, release vasoactive and angiogenic compounds, and pro-inflammatory mediators, such as arachidonic acid metabolites, histamine, cytokines/chemokines, platelet activating factor (PAF) and proteolytic enzymes. Mast cells can be activated by pro-inflammatory stimuli, including cytokines, hypercholesterolemia, and hyperglycemia, and trigger the endothelial expression of adhesion molecules such as P-selection, vascular cell adhesion molecule-1 (VCAM-1) and chemokines which mediate the recruitment and adhesion of leukocytes. The participation of mast cells in atherosclerosis is still an enigma and it may be of therapeutic interest to clarify this process.

Human-derived cathelicidin LL-37 directly activates mast cells to proinflammatory mediator synthesis and migratory response

Cathelicidins, a family of antimicrobial peptides, are well known for their role in host defense, particularly against bacteria. Apart from direct killing of microbes through the membrane disruption, cathelicidins can also exert immunomodulatory effects on cells involved in inflammatory processes. Considering the important role of mast cells in inflammation, the aim of this study was to determine whether LL-37, human-derived cathelicidin, can induce mast cell activation. We have observed that LL-37 directly stimulates mast cell to degranulation and production of some proinflammatory cytokines, but fails to induce cysteinyl leukotriene generation and release. We have also documented that LL-37 acts as a strong mast cell chemoattractant. In intracellular signaling in mast cells activated by LL-37 participates PLC/A2 and, in part, MAPKs, and PI3K. In conclusion, our results indicate that cathelicidins may enhance antibacterial inflammatory response via attracting mast cell to pathogen entry site and via induction of mast cell-derived mediator release.

Adipose triglyceride lipase regulates eicosanoid production in activated human mast cells

Human mast cells (MCs) contain TG-rich cytoplasmic lipid droplets (LDs) with high arachidonic acid (AA) content. Here, we investigated the functional role of adipose TG lipase (ATGL) in TG hydrolysis and the ensuing release of AA as substrate for eicosanoid generation by activated human primary MCs in culture. Silencing of ATGL in MCs by siRNAs induced the accumulation of neutral lipids in LDs. IgE-dependent activation of MCs triggered the secretion of the two major eicosanoids, prostaglandin D2 (PGD2) and leukotriene C4 (LTC4). The immediate release of PGD2 from the activated MCs was solely dependent on cyclooxygenase (COX) 1, while during the delayed phase of lipid mediator production, the inducible COX-2 also contributed to its release. Importantly, when ATGL-silenced MCs were activated, the secretion of both PGD2 and LTC4 was significantly reduced. Interestingly, the inhibitory effect on the release of LTC4 was even more pronounced in ATGL-silenced MCs than in cytosolic phospholipase A2-silenced MCs. These data show that ATGL hydrolyzes AA-containing TGs present in human MC LDs and define ATGL as a novel regulator of the substrate availability of AA for eicosanoid generation upon MC activation.

Mast cells in chronic inflammation, pelvic pain and depression in women

Inflammatory and neuroinflammatory processes are increasingly recognized as critical pathophysiologic steps in the development of multiple chronic diseases and in the etiology of persistent pain and depression. Mast cells are immune cells now viewed as cellular sensors in inflammation and immunity. When stimulated, mast cells release an array of mediators to orchestrate an inflammatory response. These mediators can directly initiate tissue responses on resident cells, and may also regulate the activity of other immune cells, including central microglia. New evidence supports the involvement of peripheral and central mast cells in the development of pain processes as well as in the transition from acute, to chronic and neuropathic pain. That behavioral and endocrine states can increase the number and activation of peripheral and brain mast cells suggests that mast cells represent the immune cells that peripherally and centrally coordinate inflammatory processes in neuropsychiatric diseases such as depression and anxiety which are associated with chronic pelvic pain. Given that increasing evidence supports the activated mast cell as a director of common inflammatory pathways/mechanisms contributing to chronic and neuropathic pelvic pain and comorbid neuropsychiatric diseases, mast cells may be considered a viable target for the multifactorial management of both pain and depression.

In vivo visualization of uterine mast cells by two-photon microscopy

Transgenic mice expressing fluorescent proteins in specific cell populations are widely used for the study ofin vivobehavior of these cells. We have recently reported that uterine mast cells (uMCs) are important for implantation and placentation. However, theirin vivolocalization in uterus before and during pregnancy is unknown. Herein, we report the direct observation of uMCsin vivousing double-transgenic C57BL/6JMcpt5-Cre ROSA26-EYFPmice with high expression of enhanced yellow fluorescent protein in MC protease 5 (Cma1(Mcpt5))-expressing cells by intravital two-photon microscopy. We were able to monitor MCs livein uteroduring the murine estrous cycle and at different days of pregnancy. We demonstrated that uMCs accumulated during the receptive phase of the female (estrus) and persisted in large numbers at early pregnancy stages and around mid-gestation and declined in number in non-pregnant animals at diestrus. This intravital microscopy technique, including a custom-made microscope stage and the adaption of the surgical procedure, allowed the access of the uterus and implantations for imaging. The introduced application of intravital microscopy to C57BL/6J-Mcpt5-Cre ROSA26-EYFPmice offers a novel and powerfulin vivoapproach to further address the evident relevance of uMCs to reproductive processes with obvious clinical implications.

Modulation of basophils' degranulation and allergy-related enzymes by monomeric and dimeric naphthoquinones

Allergic disorders are characterized by an abnormal immune response towards non-infectious substances, being associated with life quality reduction and potential life-threatening reactions. The increasing prevalence of allergic disorders demands for new and effective anti-allergic treatments. Here we test the anti-allergic potential of monomeric (juglone, menadione, naphthazarin, plumbagin) and dimeric (diospyrin and diosquinone) naphthoquinones. Inhibition of RBL-2H3 rat basophils' degranulation by naphthoquinones was assessed using two complementary stimuli: IgE/antigen and calcium ionophore A23187. Additionally, we tested for the inhibition of leukotrienes production in IgE/antigen-stimulated cells, and studied hyaluronidase and lipoxidase inhibition by naphthoquinones in cell-free assays. Naphthazarin (0.1 µM) decreased degranulation induced by IgE/antigen but not A23187, suggesting a mechanism upstream of the calcium increase, unlike diospyrin (10 µM) that reduced degranulation in A23187-stimulated cells. Naphthoquinones were weak hyaluronidase inhibitors, but all inhibited soybean lipoxidase with the most lipophilic diospyrin, diosquinone and menadione being the most potent, thus suggesting a mechanism of competition with natural lipophilic substrates. Menadione was the only naphthoquinone reducing leukotriene C₄ production, with a maximal effect at 5 µM. This work expands the current knowledge on the biological properties of naphthoquinones, highlighting naphthazarin, diospyrin and menadione as potential lead compounds for structural modification in the process of improving and developing novel anti-allergic drugs.