Do mast cells link obesity and asthma?

Nanomedicine Approaches for Advanced Diagnosis and Treatment of Atherosclerosis and Related Ischemic Diseases

Cardiovascular diseases (CVDs) remain one of the major causes of mortality worldwide. In response to this and other worldwide health epidemics, nanomedicine has emerged as a rapidly evolving discipline that involves the development of innovative nanomaterials and nanotechnologies and their applications in therapy and diagnosis. Nanomedicine presents unique advantages over conventional medicines due to the superior properties intrinsic to nanoscopic therapies. Once used mainly for cancer therapies, recently, tremendous progress has been made in nanomedicine that has led to an overall improvement in the treatment and diagnosis of CVDs. This review elucidates the pathophysiology and potential targets of atherosclerosis and associated ischemic diseases. It may be fruitful to pursue future work in the nanomedicine-mediated treatment of CVDs based on these targets. A comprehensive overview is then provided featuring the latest preclinical and clinical outcomes in cardiovascular imaging, biomarker detection, tissue engineering, and nanoscale delivery, with specific emphasis on nanoparticles, nanostructured scaffolds, and nanosensors. Finally, the challenges and opportunities regarding the future development and clinical translation of nanomedicine in related fields are discussed. Overall, this review aims to provide a deep and thorough understanding of the design, application, and future development of nanomedicine for atherosclerosis and related ischemic diseases.

Relationship of sputum mast cells with clinical and inflammatory characteristics of asthma

BACKGROUND

Mast cells (MCs) are innate immune cells that regulate atopic and non-atopic inflammation in the airways. MCs play a critical role in the pathogenesis of asthma, yet their relationship to airway and systemic inflammation and clinical characteristics of asthma is poorly understood.

OBJECTIVE

To quantify MCs in induced sputum samples and understand their relationship to airway and circulatory immune cells, and clinical variables in asthma.

METHODS

We employed flow cytometry of sputum samples to quantify MCs, basophils and other immune cells in 51 participants (45 asthma and 6 non-asthma controls). Relationship of MCs to airway (n = 45) and blood (n = 19) immune cells, participant demographics, asthma history, spirometry and airways hyperresponsiveness (AHR) to hypertonic saline was determined by correlation and comparison of cut-off-based sputum MC high vs low participants.

RESULTS

Mast cells, basophils and eosinophils were increased in asthma vs non-asthma control sputum. In asthma sputum, MCs, basophils and eosinophils were significantly intercorrelated, and MCs and basophils were elevated in participants with eosinophilic asthma. MCs and basophils, but not eosinophils, correlated with AHR. Sputum MC high asthma was characterized by an increased proportion of participants with uncontrolled asthma and reduced FEV₁ and FVC. Trends towards similar clinical associations with elevated MCs were observed in a paucigranulocytic subpopulation (n = 15) lacking airway eosinophilia or neutrophilia. Receiver operator characteristic (ROC) analysis showed peripheral blood eosinophil (PBE) count predicted elevated sputum eosinophils and basophils, but not MCs.

CONCLUSIONS AND CLINICAL RELEVANCE

Sputum MCs are elevated in asthma, and their measurement may be useful as they relate to key clinical features of asthma (spirometry, asthma control, AHR). PBE count did not predict airway MC status, suggesting direct measurement of airway MCs by sensitive methods such as flow cytometry should be further developed.

Impact of mast cells in fibromyalgia and low-grade chronic inflammation: Can IL-37 play a role?

Fibromyalgia (FM) is a disease characterized by chronic widespread pain, fatigue, aches, joint stiffness, depression, cognitive dysfunction, and nonrestorative sleep. In FM, neurotransmission and glial activation can occur with an increase in inflammatory cytokines and involvement of mast cells (MCs) in the skin. FM skin biopsies show an increase in the number of MCs, as well as the production of corticotropin releasing hormone and substance P (SP) by the neurons, which in turn activate MCs to release neurosensitizing proinflammatory substances, such as cytokines, secreted preformed mediators, and lipids, which can exacerbate low-grade inflammation. In fact, certain proinflammatory cytokines are higher in FM and mediate muscle pain, the mechanism of which is not yet clear. MC-derived tumor necrosis factor (TNF) induces nerve growth factor (NGF) and participates in nerve fiber elongation in skin hypersensitivity. IL-37 is an inhibitor of proinflammatory IL-1 family members, which are generated and released by MCs. The goal of this article is to demonstrate that inflammatory cytokines and MC products play a role in FM and that inflammation may be inhibited by IL-37. Here, we propose IL-37 as a cytokine that contributes to improve the pathogenesis of FM by blocking IL-1 family members.

Recent advances in our understanding of mast cell activation - or should it be mast cell mediator disorders?

INTRODUCTION

An increasing number of patients present with multiple symptoms affecting many organs including the brain due to multiple mediators released by mast cells. These unique tissue immune cells are critical for allergic reactions triggered by immunoglobulin E (IgE), but are also stimulated (not activated) by immune, drug, environmental, food, infectious, and stress triggers, leading to secretion of multiple mediators often without histamine and tryptase. The presentation, diagnosis, and management of the spectrum of mast cell disorders are very confusing. As a result, neuropsychiatric symptoms have been left out, and diagnostic criteria made stricter excluding most patients. Areas covered: A literature search was performed on papers published between January 1990 and November 2018 using MEDLINE. Terms used were activation, antihistamines, atopy, autism, brain fog, heparin, KIT mutation, IgE, inflammation, IL-6, IL-31, IL-37, luteolin, mast cells, mastocytosis, mediators, mycotoxins, release, secretion, tetramethoxyluteolin, and tryptase. Expert opinion: Conditions associated with elevated serum or urine levels of any mast cell mediator, in the absence of comorbidities that could explain elevated levels, should be considered 'Mast Cell Mediator Disorders (MCMD).' Emphasis should be placed on the identification of unique mast cell mediators, and development of drugs or supplements that inhibit their release.

Obese- and allergic-related asthma phenotypes among children across the United States

OBJECTIVES

Pediatric asthma is heterogeneous with phenotypes that reflect differing underlying inflammation and pathophysiology. Little is known about the national prevalence of certain obesity- and allergy-related asthma phenotypes or associated characteristics. We therefore assessed the national prevalence, risk factors, and caregiver-reported severity of four asthma phenotypes: not-allergic-not-obese, allergic-not-obese, obese-not-allergic, and allergic-and-obese.

METHODS

We analyzed data from the 2007-2008 National Survey of Children's Health (NSCH) of 10-17 year-olds with caregiver-reported asthma. We described sociodemographic and health risk factors of each phenotype and then applied logistic and ordinal regression models to identify associated risk factors and level of severity of the phenotypes.

RESULTS

Among 4427 children with asthma in this NSCH cohort, the association between race and phenotype was statistically significant (p < 0.0001); white children with asthma were most likely to have allergic-not-obese asthma while black and Hispanic children with asthma were most likely to have the obese-nonallergic phenotype (p < 0.001). Attention-deficit disorder/attention-deficit hyperactivity disorder was more likely to be present in allergic-not-obese children (odds ratio (OR) 1.50, confidence interval (CI) 1.14-1.98, p = 0.004). The phenotype with the highest risk for more severe compared to mild asthma was the obese-and-allergic asthma phenotype (OR 3.34, CI 2.23-5.01, p < 0.001).

CONCLUSIONS

Allergic-not-obese asthma comprised half of our studied asthma phenotypes, while obesity-related asthma (with or without allergic components) comprised one-fifth of asthma phenotypes in this cohort representative of the US population. Children with both obese and allergic asthma are most likely to have severe asthma. Future management of childhood asthma might consider more tailoring of treatment and management plans based upon different childhood asthma phenotypes.

Discovering Pediatric Asthma Phenotypes on the Basis of Response to Controller Medication Using Machine Learning

RATIONALE

Pediatric asthma has variable underlying inflammation and symptom control. Approaches to addressing this heterogeneity, such as clustering methods to find phenotypes and predict outcomes, have been investigated. However, clustering based on the relationship between treatment and clinical outcome has not been performed, and machine learning approaches for long-term outcome prediction in pediatric asthma have not been studied in depth.

OBJECTIVES

Our objectives were to use our novel machine learning algorithm, predictor pursuit (PP), to discover pediatric asthma phenotypes on the basis of asthma control in response to controller medications, to predict longitudinal asthma control among children with asthma, and to identify features associated with asthma control within each discovered pediatric phenotype.

METHODS

We applied PP to the Childhood Asthma Management Program study data (n = 1,019) to discover phenotypes on the basis of asthma control between assigned controller therapy groups (budesonide vs. nedocromil). We confirmed PP's ability to discover phenotypes using the Asthma Clinical Research Network/Childhood Asthma Research and Education network data. We next predicted children's asthma control over time and compared PP's performance with that of traditional prediction methods. Last, we identified clinical features most correlated with asthma control in the discovered phenotypes.

RESULTS

Four phenotypes were discovered in both datasets: allergic not obese (A⁺/O^-), obese not allergic (A^-/O⁺), allergic and obese (A⁺/O⁺), and not allergic not obese (A^-/O^-). Of the children with well-controlled asthma in the Childhood Asthma Management Program dataset, we found more nonobese children treated with budesonide than with nedocromil (P = 0.015) and more obese children treated with nedocromil than with budesonide (P = 0.008). Within the obese group, more A⁺/O⁺ children's asthma was well controlled with nedocromil than with budesonide (P = 0.022) or with placebo (P = 0.011). The PP algorithm performed significantly better (P < 0.001) than traditional machine learning algorithms for both short- and long-term asthma control prediction. Asthma control and bronchodilator response were the features most predictive of short-term asthma control, regardless of type of controller medication or phenotype. Bronchodilator response and serum eosinophils were the most predictive features of asthma control, regardless of type of controller medication or phenotype.

CONCLUSIONS

Advanced statistical machine learning approaches can be powerful tools for discovery of phenotypes based on treatment response and can aid in asthma control prediction in complex medical conditions such as asthma.

Immunometabolism features of metabolic deregulation and cancer

Immunometabolism is a branch dealing at the interface of immune functionalities and metabolic regulations. Considered as a bidirectional trafficking, metabolic contents and their precursors bring a considerable change in immune cells signal transductions which as a result affect the metabolic organs and states as an implication. Lipid metabolic ingredients form a major chunk of daily diet and have a proven contribution in immune cells induction, which then undergo metabolic pathway shuffling inside their ownself. Lipid metabolic states activate relevant metabolic pathways inside immune cells that in turn prime appropriate responses to outside environment in various states including lipid metabolic disorders itself and cancers as an extension. Although data on Immunometabolism are still growing, but scientific community need to adjust and readjust according to recent data on given subject. This review attempts to provide current important data on Immunometabolism and consequently its metabolic ramifications. Incumbent data on various lipid metabolic deregulations like obesity, metabolic syndrome, obese asthma and atherosclerosis are analysed. Further, metabolic repercussions on cancers and its immune modalities are also analysed.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome-Metabolic Disease or Disturbed Homeostasis due to Focal Inflammation in the Hypothalamus?

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex disease characterized by debilitating fatigue, lasting for at least 6 months, with associated malaise, headaches, sleep disturbance, and cognitive impairment, which severely impacts quality of life. A significant percentage of ME/CFS patients remain undiagnosed, mainly due to the complexity of the disease and the lack of reliable objective biomarkers. ME/CFS patients display decreased metabolism and the severity of symptoms appears to be directly correlated to the degree of metabolic reduction that may be unique to each individual patient. However, the precise pathogenesis is still unknown, preventing the development of effective treatments. The ME/CFS phenotype has been associated with abnormalities in energy metabolism, which are apparently due to mitochondrial dysfunction in the absence of mitochondrial diseases, resulting in reduced oxidative metabolism. Such mitochondria may be further contributing to the ME/CFS symptomatology by extracellular secretion of mitochondrial DNA, which could act as an innate pathogen and create an autoinflammatory state in the hypothalamus. We propose that stimulation of hypothalamic mast cells by environmental, neuroimmune, pathogenic and stress triggers activates microglia, leading to focal inflammation in the brain and disturbed homeostasis. This process could be targeted for the development of novel effective treatments.

Critical role of inflammatory mast cell in fibrosis: Potential therapeutic effect of IL-37

BACKGROUND

Fibrosis involves the activation of inflammatory cells, leading to a decrease in physiological function of the affected organ or tissue.

AIMS

To update and synthesize relevant information concerning fibrosis into a new hypothesis to explain the pathogenesis of fibrosis and propose potential novel therapeutic approaches.

MATERIALS AND METHODS

Literature was reviewed and relevant information is discussed in the context of the pathogenesis of fibrosis.

RESULTS

A number of cytokines and their mRNA are involved in the circulatory system and in organs of patients with fibrotic tissues. The profibrotic cytokines are generated by several activated immune cells, including fibroblasts and mast cells (MCs), which are important for tissue inflammatory responses to different types of injury. MC-derived TNF, IL-1, and IL-33 contribute crucially to the initiation of a cascade of the host defence mechanism(s), leading to the fibrosis process. Inhibition of TNF and inflammatory cytokines may slow the progression of fibrosis and improve the pathological status of the affected subject. IL-37 is generated by various types of immune cells and is an IL-1 family member protein. IL-37 is not a receptor antagonist; it binds IL-18 receptor alpha (IL-18Rα) and delivers the inhibitory signal by using TIR8. It has been shown that IL-37 can be protective in inflammation and injury, and inhibits both innate and adaptive immunity.

DISCUSSION

IL-37 may be useful for suppression of inflammatory diseases induced by inhibiting MyD88-dependent TLR signalling. In addition, IL-37 downregulates NF-κB induced by TLR2 or TLR4 through a mechanism dependent on IL-18Rα.

CONCLUSION

This review summarizes current knowledge on the role of MC in inflammation and tissue/organ fibrosis, with a focus on the therapeutic potential of IL-37-targeting cytokines.

Potential therapeutic use of IL-37: a key suppressor of innate immunity and allergic immune responses mediated by mast cells

The host response to either exogenous or endogenous insults produces a series of changes, characterized by alterations in immunological functions and generation of mediators called cytokines which include the interleukin-1 (IL-1) family members. IL-1 acts as a hormone mediating the host responses to infection and inflammation. Blocking inflammatory IL-1 family members can be effective against inflammatory disorders, including allergies. IL-37, (formerly IL-1 family member 7), emerges as an inhibitor of innate and adaptive immunity by reducing circulating and organ cytokine levels. IL-37, mainly expressed in dendritic cells, monocytes, and plasma cells after TIR ligand activation, inhibits inflammatory cytokines and augments the level of anti-inflammatory IL-10. IL-37 is involved in allergic reaction and its expression in dendritic cells causes tollerogenicity and inhibits inflammatory response. Mast cells (MCs) are ubiquitous in the body, reside in numerous mucosal tissues, and are mediators of allergic reaction, and innate and adaptive immunity. MCs are important regulators of cytokine generation in the course of inflammatory responses and allergy, and are implicated in the pathophysiology of allergic asthma. Cysteine protease caspase-1 activation leads to the cleavage of pro-form of IL-1 into active mature IL-1 which is present in stimulated and unstimulated inflammatory MCs. Inflammatory cytokine inhibition, along with the augmentation of anti-inflammatory IL-10 by IL-37, is certainly beneficial and improves the pathogenesis of allergic disorders. However, in these studies, the exact mechanism(s) of IL-37-induced anti-inflammatory and anti-allergic activity along with its side effect(s) remain to be determined.

The relationship between chronic rhinosinusitis and metabolic syndrome

BACKGROUND

This study aimed to investigate the correlation between metabolic syndrome and chronic rhinosinusitis (CRS), with related risk factors for CRS according to data from the Korean National Health and Nutrition Examination Survey (KNHANES).

METHODS

The KNHANES surveyed individuals >19 years of age from January 2010 to December 2011. CRS encompassed "symptom-based CRS" as defined by the European Position Paper on Rhinosinusitis and Nasal Polyps 2012. Metabolic syndrome was diagnosed according to the American Heart Association/National Heart Lung and Blood Institute criteria. A χ2 analysis, univariate analysis, and multivariate analysis were conducted.

RESULTS

A total of 12,015 individuals were analyzed in this study. The prevalence of CRS in the patients with metabolic syndrome (high triglyceride level, reduced high-density lipoprotein level, and elevated blood pressure) was significantly higher than that in patients without metabolic syndrome (14.15 versus 10.16%) (p < 0.05). Allergic rhinitis was the only significant risk factor for CRS found to be associated with metabolic syndrome (p < 0.05).

CONCLUSION

CRS was more prevalent in patients with metabolic syndrome, especially those with allergic rhinitis, than in patients without metabolic syndrome. Accordingly, CRS should be considered in patients with metabolic syndrome and allergic rhinitis.

Estimating the causal effect of body mass index on hay fever, asthma and lung function using Mendelian randomization

BACKGROUND

Observational studies have shown that body mass index (BMI) is positively associated with asthma. However, observational data are prone to confounding and reverse causation. In Mendelian randomization, genetic variants are used as unconfounded markers of exposures to examine causal effects. We examined the causal effect of BMI on asthma, hay fever, allergic sensitization, serum total immunoglobulin E (IgE), forced expiratory volume in one-second (FEV1) and forced vital capacity (FVC).

METHODS

We included 490 497 participants in the observational and 162 124 participants in the genetic analyses. A genetic risk score (GRS) was created using 26 BMI-associated single nucleotide polymorphisms (SNPs). Results were pooled in meta-analyses and expressed as odds ratios (ORs) or β-estimates with 95% confidence interval (CI).

RESULTS

The GRS was significantly associated with asthma (OR=1.009; 95% CI: 1.004, 1.013), but not with hay fever (OR= 0.998; 95% CI: 0.994, 1.002) or allergic sensitization (OR=0.999; 95% CI: 0.986, 1.012) per BMI-increasing allele. The GRS was significantly associated with decrease in FEV1: β=-0.0012 (95% CI: -0.0019, -0.0006) and FVC: β=-0.0022 (95% CI: -0.0031, -0.0014) per BMI-increasing allele. Effect sizes estimated by instrumental variable analyses were OR=1.07 (95% CI: 1.03, 1.10) for asthma, a 9 ml decrease in FEV1 (95% CI: 2.0-15 mL decrease) and a 16 ml decrease in FVC (95% CI: 7.0-24 mL decrease) per 1 kg/m² higher BMI.

CONCLUSIONS

The results support the conclusion that increasing BMI is causally related to higher prevalence of asthma and decreased lung function, but not with hay fever or biomarkers of allergy.

Mast cells emerge as mediators of atherosclerosis: Special emphasis on IL-37 inhibition

In atherosclerosis lipoproteins stimulate the innate immune response, leading to the release of inflammatory cytokines and chemokines. Hypercholesterolemia may activate the synthesis and release of inflammatory cytokines such as IL-1, which induces TNF release in mast cells (MCs). IL-1 and IL-1 family members orchestrate a broadening list of inflammatory diseases, including atherosclerosis. MCs are implicated in the pathophysiology of several diseases including allergy and inflammation. Activated MCs, located perivascularly, contribute to inflammation in atherosclerosis by producing inflammatory cytokines. MC IL-1-activation leads to the immediate release of inflammatory chemical mediators and TNF, and late inflammatory compounds such as cytokines. MCs can be activated by exogenous cytokines, antigens, microbial products (LPS) and neurotransmitters and generate IL-1 beta, TNF and several other inflammatory cytokines/chemokines along with PGD2, leukotrienes, histamine and proteases. MCs activated with IL-1 induce selective release of IL-6 without degranulation. TNF emerges as one of the most potent inflammatory cytokines involved in the response due to LDL. Cytokines, such as IL-1, IL-6, IL-33 and TNF, are generated in the inflammatory sites by both macrophages and MCs, mediating atherosclerosis. IL-37 (IL-1 family member 7) binds IL-18Ra chain and acts by an intracellular mechanism down-regulating the expression of pro-inflammatory signals cJun, MAP kinase p38a, STAT transcription factors and p53. Blocking IL-1 with IL-37 alleviates the symptoms in patients with inflammatory diseases including arteriosclerosis. The impact of IL-37 on inflammatory cytokines mediating atherosclerosis is beneficial and protective. However, more studies are needed to better define this mechanism and the safety and tolerability of IL-37.

IL-37 a New IL-1 Family Member Emerges as a Key Suppressor of Asthma Mediated by Mast Cells

In 1986, we reported a multiple biological effect of IL-1 including immunological, inflammatory, and tumor killing activity. Since then other IL-1 family cytokines have been discovered, some with inflammatory and other with anti-inflammatory activity. In this review article, we speculate on the possible inhibitory effect of IL-37 in the light of new findings. IL-37, formerly termed IL-1 family member 7 (IL-1F7), binding IL-18 receptor α chain, acts as a cytokine with intracellular as well as extracellular functionality and as a natural inhibitor of immune responses and inflammation. IL-37 inhibits many pro-inflammatory cytokine and increases anti-inflammatory cytokines such as IL-10. Asthma pathogenesis involves multiple cell types including mast cells, which are important cellular constituents of the human innate and adaptive immunity. IL-37 has an impact on inflammatory cytokines generated by mast cells and is beneficial for and protective in asthma. However, the precise mechanism(s), safety, and tolerability of IL-37 are unclear and still remain a mystery.

ABBREVIATIONS

GBP (Guanylate Binding Proteins); HMGB1 (High Mobility Group Box protein 1); NLRP (Nucleotide-like Receptor Pyrin domain 1); ASC (Apoptosis-associated Speck-like protein containing CARD, Caspase Recruitment Domain); FGF2 (Fibroblast Growth Factor 2).

Association between obesity and asthma - epidemiology, pathophysiology and clinical profile

Obesity is a risk factor for asthma, and obese asthmatics have lower disease control and increased symptom severity. Several putative links have been proposed, including genetics, mechanical restriction of the chest and the intake of corticosteroids. The most consistent evidence, however, comes from studies of cytokines produced by the adipose tissue called adipokines. Adipokine imbalance is associated with both proinflammatory status and asthma. Although reverse causation has been proposed, it is now acknowledged that obesity precedes asthma symptoms. Nevertheless, prenatal origins of both conditions complicate the search for causality. There is a confirmed role of neuro-immune cross-talk mediating obesity-induced asthma, with leptin playing a key role in these processes. Obesity-induced asthma is now considered a distinct asthma phenotype. In fact, it is one of the most important determinants of asthma phenotypes. Two main subphenotypes have been distinguished. The first phenotype, which affects adult women, is characterised by later onset and is more likely to be non-atopic. The childhood obesity-induced asthma phenotype is characterised by primary and predominantly atopic asthma. In obesity-induced asthma, the immune responses are shifted towards T helper (Th) 1 polarisation rather than the typical atopic Th2 immunological profile. Moreover, obese asthmatics might respond differently to environmental triggers. The high cost of treatment of obesity-related asthma, and the burden it causes for the patients and their families call for urgent intervention. Phenotype-specific approaches seem to be crucial for the success of prevention and treatment.

Epidemiology of chronic spontaneous urticaria: results from a nationwide, population-based study in Italy

BACKGROUND

Chronic spontaneous urticaria (CSU) is a common skin disease, but there is a paucity of precise epidemiological data on this disease.

OBJECTIVES

To obtain information on the epidemiology of CSU in Italy.

METHODS

The data source was the Health Search IMS Health Longitudinal Patient Database. The study population was formed by patients aged ≥ 15 years, registered with a total of 700 general practitioners, homogeneously distributed across Italy. An algorithm based on the International Classification of Diseases, ninth revision, Clinical Modification was used for the identification of patients with CSU. The annual prevalence and incidence rates of CSU over a 12-year period (2002-2013) were estimated, along with demographic and clinical determinants.

RESULTS

The annual prevalence of CSU ranged from 0·02% in 2002 to 0·38% in 2013. The incidence was 0·10-1·50 per 1000 person-years. For both prevalence and incidence rates, female patients outnumbered male. The risk of CSU was statistically significantly higher in the presence of the following variables: obesity; anxiety, dissociative and somatoform disorders; malignancies; use of immunosuppressive drugs; and chronic use of systemic corticosteroids. History of autoimmune thyroiditis showed a trend towards an increased risk of CSU, though it was not statistically significant. Smoking was associated with a significantly reduced risk of CSU.

CONCLUSIONS

Our findings on CSU prevalence are consistent with those obtained in previous studies. Furthermore, this large population-based study provides important information regarding the association of CSU with demographic and clinical determinants, which have been examined in the primary-care setting.

Increased asthma and adipose tissue inflammatory gene expression with obesity and Inuit migration to a western country

BACKGROUND

An overlap between obesity and asthma exists, and inflammatory cells in adipose tissue could drive the development of asthma. Comparison of adipose tissue gene expression among Inuit living in Greenland to those in Denmark provides an opportunity to assess how changes in adipose tissue inflammation can be modified by migration and diet.

OBJECTIVE

To examine mast cell and inflammatory markers in adipose tissue and the association with asthma.

METHODS

Two Inuit populations were recruited, one living in Greenland and another in Denmark. All underwent adipose subcutaneous biopsy, followed by clinical assessment of asthma, and measurement of AHR. Adipose tissue biopsies were homogenised, RNA extracted, and PCR was performed to determine the relative gene expression of mast cell (tryptase, chymase, CPA3) and inflammatory markers (IL-6, IL-1β, and CD163).

RESULTS

Of the 1059 Greenlandic Inuit participants, 556 were living in Greenland and 6.4% had asthma. Asthma was increased in Denmark (9%) compared to Greenland (3.6%, p < 0.0001) and associated with increased adipose tissue IL-6 gene expression and increased BMI. There was no association between asthma and adipose tissue mast cell gene expression. Pro-inflammatory gene expression (IL-6, IL-1β) was higher in those living in Denmark, and with increasing BMI and dietary changes. The anti-inflammatory (M2) macrophage marker, CD163, was higher in Greenland-dwelling Inuit (p < 0.01).

CONCLUSIONS

No association was found between gene expression of mast cell markers in adipose tissue and asthma. Among Greenlandic Inuit, adipose tissue inflammation is also increased in those who migrate to Denmark, possibly as a result of dietary changes.

Brain "fog," inflammation and obesity: key aspects of neuropsychiatric disorders improved by luteolin

Brain "fog" is a constellation of symptoms that include reduced cognition, inability to concentrate and multitask, as well as loss of short and long term memory. Brain "fog" characterizes patients with autism spectrum disorders (ASDs), celiac disease, chronic fatigue syndrome, fibromyalgia, mastocytosis, and postural tachycardia syndrome (POTS), as well as "minimal cognitive impairment," an early clinical presentation of Alzheimer's disease (AD), and other neuropsychiatric disorders. Brain "fog" may be due to inflammatory molecules, including adipocytokines and histamine released from mast cells (MCs) further stimulating microglia activation, and causing focal brain inflammation. Recent reviews have described the potential use of natural flavonoids for the treatment of neuropsychiatric and neurodegenerative diseases. The flavone luteolin has numerous useful actions that include: anti-oxidant, anti-inflammatory, microglia inhibition, neuroprotection, and memory increase. A liposomal luteolin formulation in olive fruit extract improved attention in children with ASDs and brain "fog" in mastocytosis patients. Methylated luteolin analogs with increased activity and better bioavailability could be developed into effective treatments for neuropsychiatric disorders and brain "fog."

The role of Lin28b in myeloid and mast cell differentiation and mast cell malignancy

Mast cells (MCs) are critical components of the innate immune system and important for host defense, allergy, autoimmunity, tissue regeneration and tumor progression. Dysregulated MC development leads to systemic mastocytosis (SM), a clinically variable but often devastating family of hematologic disorders. Here we report that induced expression of Lin28, a heterochronic gene and pluripotency factor implicated in driving a fetal hematopoietic program, caused MC accumulation in adult mice in target organs such as the skin and peritoneal cavity. In vitro assays revealed a skewing of myeloid commitment in LIN28B-expressing hematopoietic progenitors, with increased levels of LIN28B in common myeloid and basophil-MC progenitors altering gene expression patterns to favor cell fate choices that enhanced MC specification. In addition, LIN28B-induced MCs appeared phenotypically and functionally immature, and in vitro assays suggested a slowing of MC terminal differentiation in the context of LIN28B upregulation. Finally, interrogation of human MC leukemia samples revealed upregulation of LIN28B in abnormal MCs from patients with SM. This work identifies Lin28 as a novel regulator of innate immune function and a new protein of interest in MC disease.

The impact of mast cells on cardiovascular diseases

Mast cells comprise an innate immune cell population, which accumulates in tissues proximal to the outside environment and, upon activation, augments the progression of immunological reactions through the release and diffusion of either pre-formed or newly generated mediators. The released products of mast cells include histamine, proteases, as well as a variety of cytokines, chemokines and growth factors, which act on the surrounding microenvironment thereby shaping the immune responses triggered in various diseased states. Mast cells have also been detected in the arterial wall and are implicated in the onset and progression of numerous cardiovascular diseases. Notably, modulation of distinct mast cell actions using genetic and pharmacological approaches highlights the crucial role of this cell type in cardiovascular syndromes. The acquired evidence renders mast cells and their mediators as potential prognostic markers and therapeutic targets in a broad spectrum of pathophysiological conditions related to cardiovascular diseases.

The novel flavone tetramethoxyluteolin is a potent inhibitor of human mast cells

BACKGROUND

Mast cells (MCs) are hematopoietic cells that mature in tissues and are involved in allergy, immunity, and inflammation by secreting multiple mediators. The natural flavone luteolin has anti-inflammatory actions and inhibits human mast cells (MCs).

OBJECTIVE

We sought to investigate the ability of luteolin and its novel structural analog 3',4',5,7-tetramethoxyluteolin (methlut) to inhibit human MC mediator expression and release in vitro and in vivo.

METHODS

Human LAD2 cells and umbilical primary human cord blood-derived cultured mast cells were stimulated with substance P (SP) or IgE/anti-IgE with or without preincubation with luteolin, methlut, or cromolyn (1-100 μmol/L) for 2 or 24 hours, after which mediator secretion was measured. The effect of the compounds on MC intracellular calcium levels and nuclear factor κB activation was also investigated. Pretreatment with methlut was also studied in mice passively sensitized with dinitrophenol-human serum albumin and challenged intradermally.

RESULTS

Methlut is a more potent inhibitor than luteolin or cromolyn for β-hexosaminidase and histamine secretion from LAD2 cells stimulated by either SP or IgE/anti-IgE, but only methlut and luteolin significantly inhibit preformed TNF secretion. Methlut is also a more potent inhibitor than luteolin of de novo-synthesized TNF from LAD2 cells and of CCL2 from human cord blood-derived cultured MCs. This mechanism of action for methlut might be due to its ability to inhibit intracellular calcium level increases, as well as nuclear factor κB induction, at both the transcriptional and translational levels in LAD2 cells stimulated by SP without affecting cell viability. Intraperitoneal treatment with methlut significantly decreases skin vascular permeability of Evans blue dye in mice passively sensitized to dinitrophenol-human serum albumin and challenged intradermally.

CONCLUSION

Methlut is a promising MC inhibitor for the treatment of allergic and inflammatory conditions.

Effect of ketotifen in obese patients with type 2 diabetes mellitus

AIM

Mast cells are found to be an important contributor in obesity induced insulin resistance. We evaluate the effect of ketotifen in obese patient with type 2 diabetes (T2DM) treated with glimepiride.

METHOD

In a randomized controlled study we recruited forty-eight obese patients with T2DM from Internal Medicine Department at Tanta University Hospital, Egypt. They were classified into three groups: group 1, those who received glimepiride (GL) 3mg/d alone; group 2, those who received GL 3mg/d+ketotifen 1mg once daily; and group 3, those who received GL 3mg/d+ketotifen 1mg twice daily. Fasting blood samples were obtained before and 12weeks after treatment for biochemical analysis of glycemic and inflammatory biomarkers. Data were statistically analyzed by paired Student's t-test and one way analysis of variance; p<0.05 was considered statistically significant.

RESULTS

The obtained data suggested that the addition of ketotifen in twice daily dose has a beneficial effect on all measured parameters except adiponectin. However, glimepiride plus ketotifen once daily only affected the level of inflammatory biomarkers without any significant effect on other parameters.

CONCLUSIONS

The co-administration of ketotifen twice daily plus glimepiride improves glycemic and inflammatory process in obese patients with T2DM.

Corticotropin-releasing hormone, microglia and mental disorders

Microglia derive from mononuclear myeloid progenitors and are a major glial complement of the central nervous system. When microglia are activated they secrete inflammatory cytokines and toxic mediators which amplify the inflammatory response. In addition, the microglia inflammatory products are implicated in the neuronal destruction usually observed in various neurodegenerative diseases. Microglia cells express corticotropin releasing hormone (CRH) receptors, and activation of microglia by CRH releases bioactive molecules which have a biological effect in the brain and regulate several neurological diseases. CRH plays a pivotal role in stress responses and is a key mediator of the hypothalamic-pituitary-adrenocortical system. CRH is expressed in human mast cells, leading to autocrine effects and participates in inflammatory response together with neuropeptides, and stimulates mast cells. IL-33-activated mast cells release vascular endothelial growth factor in response to CRH and act synergistically to increase vascular permeability. CRH also up-regulates IL-18 expression by increasing intracellular reactive oxygen in microglia cells. Here we report the relationship between CRH, microglia and mental disorders.

Spectrum of mast cell activation disorders

Mast cell (MC) activation disorders present with multiple symptoms including flushing, pruritus, hypotension, gastrointestinal complaints, irritability, headaches, concentration/memory loss and neuropsychiatric issues. These disorders are classified as: cutaneous and systemic mastocytosis with a c-kit mutation and clonal MC activation disorder, allergies, urticarias and inflammatory disorders and mast cell activation syndrome (MCAS), idiopathic urticaria and angioedema. MCs are activated by IgE, but also by cytokines, environmental, food, infectious, drug and stress triggers, leading to secretion of multiple mediators. The symptom profile and comorbidities associated with these disorders, such as chronic fatigue syndrome and fibromyalgia, are confusing. We propose the use of the term 'spectrum' and highlight the main symptoms, useful diagnostic tests and treatment approaches.

Asthma and Mast Cell Biology

Asthma is a chronic inflammatory disease of the lung and its pathophysiology is initiated by mast cell activation in response to the antigen binding to IgE receptor as well as by TH2 cell activation. Mast cells are well established effector cells in asthma where they exacerbate the inflammatory response, playing a key role in early phase, degranulating and increasing histamine. Human mast cells possess high affinity IgE receptors and are ubiquitous but predominantly localized in mucosal and connective tissue and are distributed along blood vessels. There are two types of mast cells: connective tissue mast cells (TC) and mucosal mast cells (T mast cells). TC mast cells contain more heparin, whereas T mast cells contain more chondroitin sulfate. In asthma, mast cell activation can trigger degranulation, releasing secretory granule complex and preformed mediators, such as histamine and proteases, along with the synthesis of leukotrines and prostaglandins, and induction of cytokines and chemokines. Leukotrine inhibitors and omalizumab, which inhibits IgE, both relieve the asthma exacerbation when administered to humans and permit to reduce the use of other drugs. The release of cytokines by mast cells, such as TNF-alpha, IL-1, IL-6 and IL-33, participate in the pathogenesis of asthma. Stress worsens asthma, and this effect is also mediated by mast cell activation through the release of cytokines. Administration of IL-33 in experimental animals provokes pathological effects in the mucosal tissues and augments antibody IgE and IgA in blood vessels. Here, we report the impact of mast cell biology in asthma pathogenesis.

Stress triggers coronary mast cells leading to cardiac events

OBJECTIVE

Stress precipitates and worsens not only asthma and atopic dermatitis but also acute coronary syndromes (ACSs), which are associated with coronary inflammation. Evidence linking stress to ACS was reviewed and indicated that activation of coronary mast cells (MCs) by stress, through corticotropin-releasing hormone (CRH) and other neuropeptides, contributes to coronary inflammation and coronary artery disease.

DATA SOURCES

PubMed was searched (2005-2013) for articles using the following keywords: allergies, anaphylaxis, anxiety, coronary arteries, coronary artery disease, C-reactive protein, cytokines, chymase, histamine, hypersensitivity, interleukin-6 (IL-6), inflammation, mast cells, myocardial ischemia, niacin, platelet-activating factor, rupture, spasm, statins, stress, treatment, tryptase, and uroctortin.

STUDY SELECTIONS

Articles were selected based on their relevance to how stress affects ACS and how it activates coronary MCs, leading to coronary hypersensitivity, inflammation, and coronary artery disease.

RESULTS

Stress can precipitate allergies and ACS. Stress stimulates MCs through the activation of high-affinity surface receptors for CRH, leading to a CRH-dependent increase in serum IL-6. Moreover, neurotensin secreted with CRH from peripheral nerves augments the effect of CRH and stimulates cardiac MCs to release IL-6, which is elevated in ACS and is an independent risk factor for myocardial ischemia. MCs also secrete CRH and uroctortin, which induces IL-6 release from cardiomyocytes. The presence of atherosclerosis increases the risk of cardiac MC activation owing to the stimulatory effect of lipoproteins and adipocytokines. Conditions such as Kounis syndrome, mastocytosis, and myalgic encephalopathy/chronic fatigue syndrome are particularly prone to coronary hypersensitivity reactions.

CONCLUSION

Inhibition of cardiac MCs may be a novel treatment approach.

Childhood adversity and asthma prevalence: evidence from 10 US states (2009-2011)

Background

Existing evidence on stress and asthma prevalence has disproportionately focused on pregnancy and postpregnancy early life stressors, largely ignoring the role of childhood adversity as a risk factor. Childhood adversity (neglect, stressful living conditions and maltreatment) may influence asthma prevalence through mechanisms on the hypothalamic-pituitary axis.

Methods

Data from the Center for Disease Control's (CDC's) Behavioral Risk Factor Surveillance System (BRFSS) surveys were used to examine cross-sectional associations of adverse childhood experiences (ACE) with lifetime and current asthma prevalence. Information on childhood adversity was available from 84 786 adult respondents in 10 US states. Poisson regression models (with robust SE) were used to estimate prevalence ratios (PRs) relating overall ACE score and dimensions of exposure ACE to asthma prevalence, adjusting for socioeconomic status.

Results

Greater ACE was associated with a higher prevalence of asthma (adjusted PR_{cat 4}=1.78 (95% CI 1.69 to 1.87), adjusted PR_{cat 1}=1.21 (95% CI 1.16 to 1.27)). Reported experiences of sexual abuse (adjusted PR=1.48* (1.42 to 1.55)) and physical abuse (adjusted PR=1.38* (1.33 to 1.43)) were associated with a higher asthma prevalence. No clear socioeconomic gradient was noted, but those reporting lowest education and income levels reported high rates of asthma and adversity. Sensitivity analyses indicated that ACE exposures were interrelated.

Conclusions

Report of childhood adversity predicts asthma prevalence among US adults. Frameworks for asthma prevention need to recognise and integrate aspects related to childhood adversity. Further investigation into specific time periods of exposure would provide meaningful inferences for interventions.

Atopic dermatitis as a systemic disease

Atopic dermatitis (AD) is a chronic inflammatory disease that seriously affects the quality of life of these patients. Both immune deviations and epidermal barrier deficiency have been defined as pathophysiologic mechanisms in the disease development. The atopic march, or the natural progression form atopic dermatitis in infancy to asthma and allergic rhinitis, is a classic example for the multiorgan involvement in atopy. It has been hypothesized that epidermal barrier impairment is the primary pathologic condition responsible for the atopic march. In recent decades, a growing body of evidence has accumulated that AD can be accompanied by a variety of systemic diseases, such as autoimmune disorders, ophthalmologic involvement, eosinophilic gastroenteritis, inflammatory bowel disease, nephritic syndrome, and metabolic diseases. This contribution reviews these associations and focuses on the possible common underlying mechanisms of AD and the associated syndromes. We present a concept on AD as a multiorgan systemic disease.

Immunometabolism in obese asthmatics: are we there yet?

Obesity is now recognised as a worldwide epidemic. The recent International Association for the Study of Obesity/International Obesity Taskforce (IASO/IOTF) analysis estimates that approximately 1.0 billion adults are currently overweight and a further 475 million are obese. Obesity has huge psychosocial impact with obese children and adolescents facing discrimination and stigmatization in many areas of their lives leading to body dissatisfaction, low self-esteem and depression. Indeed, obesity is recognised as an important risk factor for the development of several chronic diseases such as hypertension, cancer, asthma and metabolic syndrome. Chronic low grade systemic inflammation is considered as a hallmark of obesity and may possibly explain the link between obesity and chronic disease, in particular the increased incidence, prevalence and severity of asthma in obese individuals. There is now strong evidence for infiltration of immune and inflammatory cells into adipose tissue that drives systemic inflammation and subsequent end organ damage. In addition to adipocytes, the key adipose tissue resident immune cells are macrophages and mast cells. Immunometabolism, as an emerging field of investigation, explores the pivotal role of these immune cells in translating immunological changes to metabolic effects in obesity. Abundance of free fatty acids, along with other inflammatory cytokines shift the balance of metabolic homeostasis to pro-inflammatory status by influencing the development of inflammatory cell lineage, which, further exhibits distinct functional phenotypes. There is emerging evidence for macrophage activation and functional polarization of an anti-inflammatory M₂ phenotype towards a pro-inflammatory M₁ phenotype of macrophages in obese adipose tissue. Similarly, studies in both obese humans and murine models reveal the pathognomic presence of an increased number of mast cells in visceral adipose tissue. These suggest a possible contribution of mast cells to the unique metabolome of obese asthma. This review examines proposed multilevel interactions between metabolic and immune systems in obese asthmatics that underlie the negative effects of obesity and may offer significant therapeutic promise.