Mast cell stabilization: novel medication for obesity and diabetes

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.

Immune cells in adipose tissue microenvironment under physiological and obese conditions

PURPOSE

This review will focus on the immune cells in adipose tissue microenvironment and their regulatory roles in metabolic homeostasis of adipose tissue and even the whole body under physiological and obese conditions.

METHODS

This review used PubMed searches of current literature to examine adipose tissue immune cells and cytokines, as well as the complex interactions between them.

RESULTS

Aside from serving as a passive energy depot, adipose tissue has shown specific immunological function. Adipose tissue microenvironment is enriched with a large number of immune cells and cytokines, whose physiological regulation plays a crucial role for metabolic homeostasis. However, obesity causes pro-inflammatory alterations in these adipose tissue immune cells, which have detrimental effects on metabolism and increase the susceptibility of individuals to the obesity related diseases.

CONCLUSIONS

Adipose tissue microenvironment is enriched with various immune cells and cytokines, which regulate metabolic homeostasis of adipose tissue and even the whole body, whether under physiological or obese conditions. Targeting key immune cells and cytokines in adipose tissue microenvironment for obesity treatment becomes an attractive research point.

Pediatric obesity and severe asthma: Targeting pathways driving inflammation

Asthma affects more than 300 million people of all ages worldwide, including about 10-15% of school-aged children, and its prevalence is increasing. Severe asthma (SA) is a particular and rare phenotype requiring treatment with high-dose inhaled corticosteroids plus a second controller and/or systemic glucocorticoid courses to achieve symptom control or remaining "uncontrolled" despite this therapy. In SA, other diagnoses have been excluded, and potential exacerbating factors have been addressed. Notably, obese asthmatics are at higher risk of developing SA. Obesity is both a major risk factor and a disease modifier of asthma in children and adults: two main "obese asthma" phenotypes have been described in childhood with high or low levels of Type 2 inflammation biomarkers, respectively, the former characterized by early onset and eosinophilic inflammation and the latter by neutrophilic inflammation and late-onset. Nevertheless, the interplay between obesity and asthma is far more complex and includes obese tissue-driven inflammatory pathways, mechanical factors, comorbidities, and poor response to corticosteroids. This review outlines the most recent findings on SA in obese children, particularly focusing on inflammatory pathways, which are becoming of pivotal importance in order to identify selective targets for specific treatments, such as biological agents.

Aloe-emodin, a naturally occurring anthraquinone, is a highly potent mast cell stabilizer through activating mitochondrial calcium uniporter

Mast cells play a fundamental role in immune system. Upon stimulation, they are activated via IgE dependent or independent pathway and then release granules which contain plenty of preformed constituents. Mast cell stabilizers are commonly used clinically for inhibiting the degranulation of mast cells. In the current study, we firstly identified aloe-emodin, a naturally occurring anthraquinone, was a prominent mast cell stabilizer. It could strikingly dampen IgE/FcεRI- and MAS-related G protein coupled receptor (Mrgpr)-mediated mast cell degranulation in vitro and in vivo. Mechanism study indicated that aloe-emodin rapidly and reversibly decreased cytosolic Ca²⁺ (Ca²⁺_[c]) concentration through enhancing the mitochondrial Ca²⁺ (Ca²⁺_[m]) uptake. After genetically silencing or pharmacologic inhibiting mitochondrial calcium uniporter (MCU), the effects of aloe-emodin on the Ca²⁺_[c] level and mast cell degranulation were significantly weakened. In contrast to six clinical drugs with mast cell stabilizing properties (amlexanox, tranilast, ketotifen, cromolyn disodium salt, dexamethasone and pimecrolimus), aloe-emodin showed an impressive and potent inhibitory action on the mast cell degranulation. Collectively, aloe-emodin is a highly potent mast cell stabilizer. By directly activating MCU, it decreases Ca²⁺_[c] level to suppress mast cell degranulation. Our study may provide a promising candidate for the treatment of mast cell activation-related diseases.

Cellular and Molecular Players in the Interplay between Adipose Tissue and Breast Cancer

The incidence and severity of obesity are rising in most of the world. In addition to metabolic disorders, obesity is associated with an increase in the incidence and severity of a variety of types of cancer, including breast cancer (BC). The bidirectional interaction between BC and adipose cells has been deeply investigated, although the molecular and cellular players involved in these mechanisms are far from being fully elucidated. Here, we review the current knowledge on these interactions and describe how preclinical research might be used to clarify the effects of obesity over BC progression and morbidity, with particular attention paid to promising therapeutic interventions.

The role of neutrophils in mediating stroke injury in the diabetic db/db mouse brain following hypoxia-ischemia

Diabetic mice exhibit increased mortality and morbidity following stroke. Recent studies from our laboratory have indicated that increased morbidity in diabetic db/db mice relative to their non-diabetic db/+ littermates is associated with increased levels of MMP-9 protease activity, increased blood-brain barrier (BBB) permeability, and greater neutrophil infiltration following hypoxic/ischemic (H/I) insult. Neutrophils are a major source of proteases and reactive oxygen species and studies have reported neutrophil depletion/inhibition is protective in certain models of experimental stroke. The objective of the current study is to determine the role of neutrophils in the increased morbidity seen in db/db mice following acute ischemic stroke. In this study, we found a significant increase in circulating neutrophils in the db/db mice at 4 h post H/I, which bound to endothelial cells in the ipsilateral hemisphere and infiltrated into brain tissue by 24 h of recovery. Depletion of circulating neutrophils resulted in reduced neutrophil concentrations in blood and in the ipsilateral hemispheres of the brain of both db/+ and db/db mice and decreased the levels of MMP-9 within the infarcted area. This resulted in smaller infarct size in the db/db mice compared to non-treated controls but did not affect stroke outcome in db/+ mice. While there was a significant correlation between neutrophil number and the levels of MMP-9 in the ipsilateral hemisphere of control and diabetic mice, surprisingly, neutrophil depletion had no effect on BBB permeability in either group. Thus, the current study suggests that neutrophil depletion reduces MMP-9 protease levels and improves stroke outcome in db/db mice but not in their db/+ counterparts.

The Interaction of Innate and Adaptive Immunity and Stabilization of Mast Cell Activation in Management of Infusion Related Reactions in Patients with Fabry Disease

Fabry disease (FD) is an X-linked lysosomal disorder caused by mutations in GLA gene resulting in lack of or faulty α-galactosidase A (α-GalA) enzyme. Enzyme replacement therapy (ERT) with recombinant human α-GalA enzyme (agalsidase) is the standard treatment option for FD. Infusion-related reactions (IRRs), with symptoms ranging from rigors, to fever, pain, vomiting, angioedema and diarrhea, are often seen due to immune response against the exogenous enzyme. To elucidate the mechanisms causing the IRRs in FD, eight patients who developed IRRs were investigated. All, except one, tested negative for agalsidase-specific IgE and had normal tryptase levels. Circulating dendritic cells were drastically reduced during IRRs, suggesting possible sequestration to the sites of inflammation. An increase in NK cells and a decrease in T cells were also observed. Cytokines IL-4, IL-8 and TNF-α showed a significant increase, indicating nonspecific degranulation of mast cells. All IRRs were managed successfully using a combination of standard premedications and mast cell stabilizers without any interruption of therapy. Taken together, the results indicate crosstalk between immune cells resulting in IgE-independent mast-cell-specific allergic inflammation. Mast cell stabilizers could be used to control IRRs and for safe reintroduction of agalsidase in patients previously treated with ERT.

Chymase inhibition retards albuminuria in type 2 diabetes

Chymase released from mast cells produces pro‐fibrotic, inflammatory, and vasoconstrictor agents. Studies were performed to test the hypothesis that chronic chymase inhibition provides a renal protective effect in type 2 diabetes. Diabetic (db/db) and control mice (db/m) were chronically infused with a chymase‐specific inhibitor or vehicle for 8 weeks. Baseline urinary albumin excretion (UalbV) averaged 42 ± 3 and 442 ± 32 microg/d in control (n = 22) and diabetic mice (n = 27), respectively (p < .05). After administration of chymase inhibitor to diabetic mice, the change in UalbV was significantly lower (459 ± 57 microg/d) than in vehicle‐treated diabetic mice (645 ± 108 microg/d). U_NGALV was not different at baseline between diabetic mice that would receive the chymase inhibitor (349 ± 56 ng/d, n = 6) and vehicle (373 ± 99 ng/d, n = 6) infusions, but increased significantly only in the vehicle‐treated diabetic mice (p < .05). Glomeruli of diabetic kidneys treated chronically with chymase inhibition demonstrated reduced mesangial matrix expansion compared to glomeruli from untreated diabetic mice. Plasma angiotensin II levels were not altered by chymase inhibitor treatment. In summary, chronic chymase inhibition slowed the progression of urinary albumin excretion in diabetic mice. In conclusion, renal chymase may contribute to the progression of albuminuria in type 2 diabetes renal disease.

Insulin-induced lipid body accumulation is accompanied by lipid remodelling in model mast cells

Mast cell lipid bodies are key to initiation, maintenance and resolution of inflammatory responses in tissue. Mast cell lines, primary bone marrow-derived mast cells and peripheral blood basophils present a ‘steatotic’ phenotype in response to chronic insulin exposure, where cells become loaded with lipid bodies. Here we show this state is associated with reduced histamine release, but increased capacity to release bioactive lipids. We describe the overall lipid phenotype of mast cells in this insulin-induced steatotic state and the consequences for critical cellular lipid classes involved in stages of inflammation. We show significant insulin-induced shifts in specific lipid classes, especially arachidonic acid derivatives, MUFA and PUFA, the EPA/DHA ratio, and in cardiolipins, especially those conjugated to certain DHA and EPAs. Functionally, insulin exposure markedly alters the FcϵRI-induced release of Series 4 leukotriene LTC4, Series 2 prostaglandin PGD2, Resolvin-D1, Resolvin-D2 and Resolvin-1, reflecting the expanded precursor pools and impact on both the pro-inflammation and pro-resolution bioactive lipids that are released during mast cell activation. Chronic hyperinsulinemia is a feature of obesity and progression to Type 2 Diabetes, these data suggest that mast cell release of key lipid mediators is altered in patients with metabolic syndrome.

Age related changes in the dermal mast cells and the associated changes in the dermal collagen and cells: A histological and electron microscopy study

Mast cells are widely distributed bone marrow cells. They have a crucial role in the dermal aging process. The aim of the present study was to describe the biochemical and the histological changes that occur in the aged dermal mast cells and to demonstrate the associated changes in the dermal cells and fibers as well. Sixteen male albino rats were used and divided into two groups; the control group (8-10 weeks) and the aged group (20-22 weeks). The rats were decapitated then processed for further biochemical and histological studies. The mean area fraction for collagen fibers was measured. In the aged group, there was a significant increase in the skin histamine and heparin levels if compared with the control one. Furthermore, there was an apparent increase in intact and degranulated dermal mast cells if compared with the control one. The dermal collagen bundles were apparently decreased and appeared distorted with wide spacing. Additionally, there were apparently large sized eosinophils with more cytoplasmic granules. Direct contact between mast, fibroblast, and macrophage cells was noticed. The average area fraction of collagen fibers was significantly increased in the aged group if compared with the control one. It could be concluded that the secretory activity of dermal mast cells was significantly increased in the aged skin group. Also, this study demonstrated the implicated role of mast cell in aged skin changes. Further long-term studies are needed to validate the prophylactic or therapeutic potential by intentional hindering of mast cell degranulation in aged skin.

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.

Association of body mass index and season with histamine skin reactivity in Chinese children with allergic rhinitis

BACKGROUND

To investigate the association between histamine skin reactivity and body mass index (BMI) and other clinical factors, 526 children (3-6 years old) who underwent a skin-prick test (SPT) to diagnose allergic rhinitis were enrolled.

METHODS

The SPT was carried out using 43 common allergens (commercial kit). The wheal size was analyzed. The associations between histamine reactivity and age, gender, BMI, atopy, parental smoking history, and testing season were examined.

RESULTS

Mean age was 4.6 ± 1.1 years. Among all 526 children, 202 (38.4%) had intermittent allergic rhinitis (IAR), 164 (32.1%) had IAR + persistent allergic rhinitis (PER), and 160 (30.4%) had PER. The size of the histamine skin wheal and maximum diameter for positive allergens showed significant seasonal differences (P = 0.001 and P = 0.02, respectively). Children with biparental allergy history had a higher BMI (P = 0.006). BMI (P < 0.001), summer testing (P = 0.001), and autumn testing (P < 0.001) were independently associated with the size of the histamine skin wheal. Only winter testing was independently associated with the maximal diameter for positive allergens (P = 0.002).

CONCLUSIONS

Higher histamine skin reactivity was associated with higher BMI and summer or autumn testing. Subject BMI and season should be considered for better interpretation of the SPT. The mechanisms underlying these associations require further study.

Correlation between pancreatic mast cells and the low grade inflammation in adipose tissue of experimental prediabetes

The role of mast cells (MCs) in prediabetes (Pre-DM) is not clearly elucidated. In the current study rats (n = 22 each) were divided equally into; control and Pre-DM (received high fat diet, HFD) groups. Samples from pancreas as well as from visceral adipose tissue (VAT) were studied for the consequent changes. We detected a significantly increased mast cell count (MCC) in the pancreas of Pre-DM compared to that of control. Frequent degranulation of MC granules was observed in Pre-DM. VAT of the Pre-DM had significantly increased (p < 0.05) macrophages (CD68⁺) and mast cells (tryptase⁺) compared to that of the control. A significant increase (p < 0.05) in CD68 mRNA expression as well as in the level of IL-1 β, IL-6, TNF-α and TGF- β1 was detected in VAT of Pre-DM with a significant positive correlation (p < 0.05) with the MCC. All these findings may indicate a potential role of MC in the low grade inflammation of VAT in Pre-DM.

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.

Activated Mast Cells Mediate Low-Grade Inflammation in Type 2 Diabetes: Interleukin-37 Could Be Beneficial

Mast cells (MCs) promote guest immune responses to parasites and play a critical role in allergic and inflammatory reactions. Once they have been activated, MCs release highly inflammatory compounds that can provoke serious pathologic signs that can lead to death. MCs generate a number of preformed, de novo synthesized compounds and inflammatory cytokine/chemokine synthesis in response to the high-affinity (Kd=10^-10 M) immunoglobulin E receptor triggering. Circulating MC progenitors migrate into arterial intima and develop lesions, mediating inflammation. They are involved in several disorders, including metabolic diseases, such as type 2 diabetes mellitus, in which endothelial cells release several inflammatory compounds during acute and chronic vascular damage. Certain inflammatory cytokines, such as interleukin (IL)-1 and IL-33, not only are produced by MCs but also may activate them. These effects mediate systemic inflammatory responses in metabolic disorders. Proinflammatory cytokines, such as tumor necrosis factor, IL-33 and IL-6, secreted by MCs and other immune cells, contribute to insulin resistance by activating kinases. IL-37 (IL-1 family member 7), one of the latest cytokines discovered, binds the IL-18 receptor alpha (IL-18Rα) chain and suppresses innate and acquired immunity, with a therapeutic effect. It also inhibits cytokine levels, including IL-6, IL-18, IL-33, tumor necrosis factor and IL-1, and may improve insulin production and, therefore, the pathogenesis of diabetes, stroke and cardiovascular health. This describes a new concept of inhibition of and cure for inflammatory diseases. However, the safety, dosage and tolerability of this novel therapeutic agent, IL-37, still remains to be determined.

Transcriptional and Functional Plasticity Induced by Chronic Insulin Exposure in a Mast Cell-Like Basophilic Leukemia Cell Model

Objective

Secretory granules (SG) and lipid bodies (LB) are the primary organelles that mediate functional responses in mast cells. SG contains histamine and matrix-active proteases, while LB are reservoirs of arachidonic acid and its metabolites, precursors for rapid synthesis of eicosanoids such as LTC₄. Both of these compartments can be dynamically or ontologically regulated, with metabolic and immunological stimuli altering lipid body content and granule numbers responding to contextual signals from tissue. We previously described that chronic in vitro or in vivo hyperinsulinemia expands the LB compartment with a concomitant loss of SG capacity, suggesting that this ratio is dynamically regulated. The objective of the current study is to determine if chronic insulin exposure initiates a transcriptional program that biases model mast cells towards a lipogenic state with accompanying loss of secretory granule biogenesis.

Methods

We used a basophilic leukemic cell line with mucosal mast cell-like features as a model system. We tested the hypothesis that chronic insulin exposure initiates a transcriptional program that biases these model mast cells towards a lipogenic state with accompanying loss of secretory granule biogenesis. Transcriptional arrays were used to map gene expression patterns. Biochemical, immunocytochemical and mediator release assays were used to evaluate organelle numbers and functional responses.

Results

In a mucosal mast cell model, the rat basophilic leukemia line RBL2H3, mast cell granularity and SG numbers are inversely correlated with LB numbers. Chronic insulin exposure appears to modulate gene networks involved in both lipid body biogenesis and secretory granule formation. Western blot analysis confirms upregulation of protein levels for LB proteins, and decreases in proteins that are markers for SG cargo.

Conclusions

The levels of insulin in the extracellular milieu may modify the phenotype of mast cell-like cells in vitro.

Mast Cell and M1 Macrophage Infiltration and Local Pro-Inflammatory Factors Were Attenuated with Incretin-Based Therapies in Obesity-Related Glomerulopathy

Background: The global increase of obesity parallels the obesity-related glomerulopathy (ORG) epidemic. Dipeptidyl peptidase 4 inhibitors and glucagon-like peptide-1 receptor agonists were well recognized to attenuate renal injury independent of glucose control in diabetic nephropathy. There are limited studies focusing on their effects on ORG. We explored the effects of incretin-based therapies on early ORG and the inflammatory responses involved mainly concentrated on mast cell (MC) and macrophage (M) infiltration and local pro-inflammatory factors.

Methods: ORG rat models were induced by high-fat diet and then divided into ORG vehicle, vildagliptin (3 mg/kg/day, qd) and liraglutide (200 μg/kg, bid) treated groups. After 8 weeks of treatments, albuminuria, glomerular histology, renal inflammatory cell infiltration, and pro-inflammatory factors were analyzed.

Results: Early ORG model was demonstrated by albuminuria, glomerulomegaly, foot process fusion, and mesangial and endothelial mild proliferation. Incretin-based therapies limited body weight gain and improved insulin sensitivity. ORG was alleviated, manifested by decreased average glomerular area, attenuated mesangial and endothelial cell proliferation, and revived cell-to-cell propagation of podocytes, which contributed to reduced albuminuria. Compared with ORG vehicle, MC and M1 macrophage (pro-inflammatory) infiltration and M1/M2 ratio were significantly decreased; M2 macrophage (anti-inflammatory) was not significantly increased after incretin-based treatments. Tumor necrosis factor-α (TNF-α) and IL-6 in renal cortex were significantly downregulated, while transforming growth factor-β1 (TGF-β1) remained unchanged.

Conclusions: Incretin-based treatments could alleviate high-fat diet-induced ORG partly through the systemic insulin sensitivity improvement and the attenuated local inflammation, mainly by the decrease of MC and M1 macrophage infiltration and reduction of TNF-α and IL-6.

Role of Ketotifen on metabolic profiles, inflammation and oxidative stress in diabetic rats

We aim to explore effects of Ketotifen on metabolic profiles, inflammation and oxidative stress. Sprague Dawley (SD) male rats were randomly divided into normal control group (NC) and experimental groups, and experimental group rats were fed with high-sugar and fat diet for 6 weeks. Then, experimental group rats were divided into diabetes group (DM) and ketotifen treatment group (KT). KT group was given ketotifen via Intragastric for 8 weeks with the dosage of 0.09 mg/kg/d. Fasting plasma glucose (FPG) was measured using glucose oxidase-phenol amino phenazone method. Fasting insulin (FINS), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were tested by enzyme-linked immunosorbent assay. Malondialdehyde (MDA) and superoxide dismutase (SOD) were quantified by spectrophotometer method. Before Ketotifen administration, compared with NC group, DM and KT groups showed significantly high levels of body weight, FPG, FINS, HOMA-IR, TC, TG, LDL, IL-6, TNF-α and MDA, and lower levels of HDL and SOD (All p <0.05). After 4 weeks of Ketotifen administration, levels of body weight, FPG, FINS, HOMA-IR, TC, TG, LDL, IL-6, TNF-α in KT group decreased significantly, and levels of HDL and SOD elevated significantly (All p <0.05). After 8 weeks of Ketotifen administration, levels of body weight, FPG, FINS, HOMA-IR, TC, TG, LDL, IL-6, TNF-α and MDA in KT group decreased more obviously, and levels of HDL and SOD elevated significantly further (All p <0.05). Ketotifen improved metabolic profiles, and ameliorated status of inflammation and oxidative stress.

Mast cell specific immunological biomarkers and metabolic syndrome among middle-aged and older Chinese adults

The main aim of this study is to explore whether these mast cell specific immunological biomarkers [immunoglobulin E (IgE), chymase and tryptase] is an independent risk factor of MetS and whether the combined action of these biomarkers increased the associations with MetS. Three mast cell-specific immunological biomarkers were measured using enzyme linked immunosorbent assay (ELISA). One-way analysis of covariance and logistic regression models were used for analyzing the associations between immunological biomarkers with MetS. A total of 340 participants, 82 (24.1%) individuals had diabetes mellitus, 31 (9.1%) had MetS (without diabetes mellitus) and 110 had MetS plus diabetes mellitus. After adjusting by multivariable (age, gender, smoking, and family history for hypertension), compared with no diabetes mellitus or MetS group (reference group), hs-CRP was associated with diabetes mellitus [OR (odds ratio): 2.29 (1.15-4.57, 95% CI (confidence interval), p=0.019] and MetS plus diabetes mellitus [OR: 2.20 (1.05-4.61, 95% CI), p=0.036], IgE was associated with MetS plus diabetes mellitus [OR: 2.38 (1.13-5.02, 95% CI), p=0.023]. After adjusting by multivariable, compared with reference group, most of combined elevated inflammatory or immunological biomarkers were significantly associated with diabetes mellitus or MetS with or without diabetes mellitus. Patients with established diabetes mellitus or MetS had different inflammatory or immunological cytokine profile (such as hs-CRP, IgE, chymase, tryptase), which indicated that there is an alteration in the function of the immune system in diabetes mellitus or MetS patient. But these results are requested to be further demonstrated for large sample population-based cohort study.

The Three-Herb Formula Shuang-Huang-Lian stabilizes mast cells through activation of mitochondrial calcium uniporter

Mast cells (MCs) are key effector cells of IgE-FcεRI- or MrgprX2-mediated signaling event. Shuang-Huang-Lian (SHL), a herbal formula from Chinese Pharmacopoeia, has been clinically used in type I hypersensitivity. Our previous study demonstrated that SHL exerted a non-negligible effect on MC stabilization. Herein, we sought to elucidate the molecular mechanisms of the prominent anti-allergic ability of SHL. MrgprX2- and IgE-FcεRI-mediated MC activation in vitro and in vivo models were developed by using compound 48/80 (C48/80) and shrimp tropomyosin (ST), respectively. Our data showed that SHL markedly dampened C48/80- or ST-induced MC degranulation in vitro and in vivo. Mechanistic study indicated that cytosolic Ca²⁺ (Ca²⁺_[c]) level decreased rapidly and sustainably after SHL treatment, and then returned to homeostasis when SHL was withdrawn. Moreover, SHL decreases Ca²⁺_[c] levels mainly through enhancing the mitochondrial Ca²⁺ (Ca²⁺_[m]) uptake. After genetically silencing or pharmacologic inhibiting mitochondrial calcium uniporter (MCU), the effect of SHL on the Ca²⁺_[c] level and MC degranulation was significantly weakened. Simultaneously, the activation of SHL on Ca²⁺_[m] uptake was completely lost. Collectively, by activating MCU, SHL decreases Ca²⁺_[c] level to stabilize MCs, thus exerting a remarkable anti-allergic activity, which could have considerable influences on clinical practice and research.

Antihyperglycemic activity of Albizzia lebbeck bark extract in streptozotocin-nicotinamide induced type II diabetes mellitus rats

Introduction:

Albizzia lebbeck (L.) Benth. (Family - Leguminosae) extract is a proven mast cell stabilizing agent. Mast cells are involved in the inflammatory processes leading to the diabetes mellitus.

Aim:

To evaluate the effect of A. lebbeck against experimentally induced type 2 diabetes mellitus in rats.

Materials and Method:

Female Sprague-Dawley rats were randomly allocated to six groups (n = 6). Diabetes was induced by single intraperitoneal injection of streptozotocin (50 mg/kg) given after 15 min of nicotinamide administration (110 mg/kg). Treatment with methanolic extract of A. lebbeck bark (MEAL) and metformin drug as standard was given for 21 days. Serum glucose (GLU) levels were measured on the 0 day and on 1^st, 7^th, 14^th and 21^st day after diabetes induction. After completion of study period, various biochemical parameters in serum such as - GLU, lipid profile, urea and creatinine were estimated. One-way analysis of variance followed with post-hoc Dunnett's test was used to analyse the data. Statistical significance for the values was set at P< 0.05.

Results:

MEAL significantly decreased the level of serum GLU, creatinine, urea, cholesterol, triglycerides, low-density lipoprotein-cholesterol, very low-density lipoprotein-cholesterol and increased high-density lipoprotein levels.

Conclusion:

A. lebbeck bark extract showed antihyperglycaemic activity along with antihyperlipidemic effect.

Effects of a Moderately Lower Temperature on the Proliferation and Degranulation of Rat Mast Cells

Mast cells are traditionally considered as key effector cells in IgE-mediated allergic diseases. However, the roles of mast cells have also been implicated in diverse physiological and pathological processes. Mast cells are distributed in various organs and tissues of various species. Some of the organs and tissues, such as testis, skin, and the upper part of the respiratory tract, have a temperature that is lower than the body's core temperature. The purpose of the present study was to investigate the effects of a lower temperature on the proliferation and degranulation of rat mast cells. Here, we demonstrate that cell growth was retarded at 35°C compared to 37°C for both rat peritoneal mast cells (RPMC) and RBL-2H3, a rat mast cell line. Furthermore, RPMC became more susceptible to degranulation at 35°C compared to 37°C. In contrast, degranulation of RBL-2H3 was not as sensitive to temperature change as RPMC. The functionality of mast cells in unique organs with a lower temperature warrants further analysis.

[An analysis of skin prick test reactivity to dust mite in overweight and normal weight children with allergic asthma before and after specific immunotherapy]

OBJECTIVE

To study the skin prick test (SPT) reactivity to house dust mite allergens in overweight and normal weight children with allergic asthma before and after standard subcutaneous specific immunotherapy.

METHODS

Two hundred and fifteen children with allergic asthma who had positive SPT responses to Dermatophagoides pteronyssinus (DP) and Dermatophagoides farinae (DF) were enrolled. According to the weight index, they were classified into overweight (n=63) and normal weight groups (n=152). Skin indices (SI) to DP and DF were compared between the two groups at 6 months and 1 year after standard subcutaneous specific immunotherapy.

RESULTS

The overweight group had a significantly larger histamine wheal diameter than the normal weight group after controlling the variation in testing time (P<0.05). After controlling the variation in weights, there were significant differences in the SIs to DP and DF before specific immunotherapy and at 6 months and 1 year after specific immunotherapy. At 6 months and 1 year after specific immunotherapy, the SIs to DP and DF were significantly reduced in both groups (P<0.05), and the overweight group had greater decreases in the SIs to DP and DF than the normal weight group.

CONCLUSIONS

The overweight children with allergic asthma have stronger responses to histamine than the normal weight patients. Specific immunotherapy can reduce the reactivity to dust mite allergens in children with allergic asthma. Within one year after specific immunotherapy, the overweight children with allergic asthma have a significantly greater decrease in the reactivity to dust mite allergens than the normal weight patients.

[An analysis of skin prick test reactivity to dust mite in overweight and normal weight children with allergic asthma before and after specific immunotherapy]

OBJECTIVE

To study the skin prick test (SPT) reactivity to house dust mite allergens in overweight and normal weight children with allergic asthma before and after standard subcutaneous specific immunotherapy.

METHODS

Two hundred and fifteen children with allergic asthma who had positive SPT responses to Dermatophagoides pteronyssinus (DP) and Dermatophagoides farinae (DF) were enrolled. According to the weight index, they were classified into overweight (n=63) and normal weight groups (n=152). Skin indices (SI) to DP and DF were compared between the two groups at 6 months and 1 year after standard subcutaneous specific immunotherapy.

RESULTS

The overweight group had a significantly larger histamine wheal diameter than the normal weight group after controlling the variation in testing time (P<0.05). After controlling the variation in weights, there were significant differences in the SIs to DP and DF before specific immunotherapy and at 6 months and 1 year after specific immunotherapy. At 6 months and 1 year after specific immunotherapy, the SIs to DP and DF were significantly reduced in both groups (P<0.05), and the overweight group had greater decreases in the SIs to DP and DF than the normal weight group.

CONCLUSIONS

The overweight children with allergic asthma have stronger responses to histamine than the normal weight patients. Specific immunotherapy can reduce the reactivity to dust mite allergens in children with allergic asthma. Within one year after specific immunotherapy, the overweight children with allergic asthma have a significantly greater decrease in the reactivity to dust mite allergens than the normal weight patients.

Adipose tissue inflammation in the pathogenesis of type 2 diabetes

At least 2.8 million people die each year as a result of being overweight or obese, and the biggest burden being obesity-related diseases. Overweight and obesity account for a major proportion of type 2 diabetes (T2D) cases. Obesity is associated with inflammation in adipose tissue, namely an infiltration and expansion of macrophages, which produce inflammatory cytokines that interfere with insulin signaling, and a loss of protective cells that promote adipose homeostasis. Thus, it is now clear that inflammation is an underlying cause or contributor to T2D as well as many other obesity-induced diseases, including atherosclerosis and cancer. Inflammatory pathways contribute to impaired glucose handling by adipocytes, hepatocytes, and muscle cells and interfere with insulin production and insulin signaling. This review highlights the roles of the different immune populations in lean adipose tissue and their importance in tissue homeostasis to keep inflammation at bay. We also discuss the changes that occur in these immune cells during the development of obesity, which has detrimental effects on the health of adipose tissue, and local and systemic insulin resistance.

Hematopoietic Kit Deficiency, rather than Lack of Mast Cells, Protects Mice from Obesity and Insulin Resistance

Obesity, insulin resistance, and related pathologies are associated with immune-mediated chronic inflammation. Kit mutant mice are protected from diet-induced obesity and associated co-morbidities, and this phenotype has previously been attributed to their lack of mast cells. We performed a comprehensive metabolic analysis of Kit-dependent Kit(W/Wv) and Kit-independent Cpa3(Cre/+) mast-cell-deficient mouse strains, employing diet-induced or genetic (Lep(Ob/Ob) background) models of obesity. Our results show that mast cell deficiency, in the absence of Kit mutations, plays no role in the regulation of weight gain or insulin resistance. Moreover, we provide evidence that the metabolic phenotype observed in Kit mutant mice, while independent of mast cells, is immune regulated. Our data underscore the value of definitive mast cell deficiency models to conclusively test the involvement of this enigmatic cell in immune-mediated pathologies and identify Kit as a key hematopoietic factor in the pathogenesis of metabolic syndrome.

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.

Histamine skin reactivity increases with body mass index in Korean children

OBJECTIVE

Histamine skin prick testing is most commonly used to diagnose immunoglobulin E (IgE)-mediated allergic diseases, and histamine reactivity is used as a standardized positive control in the interpretation of a skin prick test. However, reactivity to histamine differs among individuals for reasons that are poorly understood. The present study aimed to evaluate the potential association between body mass index (BMI) and histamine skin reactivity in children.

METHODS

A total of 451 children (246 boys, 205 girls) aged 7-8 years were enrolled in this study. The skin prick test was performed with 26 aeroallergens commonly found in Korea. Other information was collected, including sex, age, BMI, parental allergy history, and parental smoking status. Multivariate analysis was used to confirm the association between histamine skin reactivity and BMI.

RESULTS

The histamine wheal size was revealed to be associated with BMI (Spearman's Rho 0.161, p<0.001). This association was confirmed by multivariate analysis, after adjusting for sex, age, parental allergy history, parental smoking status, and allergic sensitization (coefficient B 0.071, 95% confidence interval 0.030-0.112).

CONCLUSIONS

Skin responses to histamine were primarily correlated with increased BMI. Further studies are needed to understand the clinical implication of BMI when interpreting the results of skin prick test.

Momordica charantia (Bitter Melon) reduces obesity-associated macrophage and mast cell infiltration as well as inflammatory cytokine expression in adipose tissues

Obesity is a world-wide epidemic disease that correlates closely with type 2 diabetes and cardiovascular diseases. Obesity-induced chronic adipose tissue inflammation is now considered as a critical contributor to the above complications. Momordica charantia (bitter melon, BM) is a traditional Chinese food and well known for its function of reducing body weight gain and insulin resistance. However, it is unclear whether BM could alleviate adipose tissue inflammation caused by obesity. In this study, C57BL/6 mice were fed high fat diet (HFD) with or without BM for 12 weeks. BM-contained diets ameliorated HFD-induced obesity and insulin resistance. Histological and real-time PCR analysis demonstrated BM not only reduced macrophage infiltration into epididymal adipose tissues (EAT) and brown adipose tissues (BAT). Flow cytometry show that BM could modify the M1/M2 phenotype ratio of macrophages in EAT. Further study showed that BM lowered mast cell recruitments in EAT, and depressed pro-inflammatory cytokine monocyte chemotactic protein-1 (MCP-1) expression in EAT and BAT as well as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) expression in EAT. Finally, ELISA analysis showed BM-contained diets also normalized serum levels of the cytokines. In summary, in concert with ameliorated insulin resistance and fat deposition, BM reduced adipose tissue inflammation in diet-induced obese (DIO) mice.

Naproxen and cromolyn as new glycogen synthase kinase 3β inhibitors for amelioration of diabetes and obesity: an investigation by docking simulation and subsequent in vitro/in vivo biochemical evaluation

Naproxen and cromolyn were investigated as new inhibitors of glycogen synthase kinase-3β (GSK-3β) in an attempt to explain their hypoglycemic properties. Study included simulated docking experiments, in vitro enzyme inhibition assay, and in vivo validations. Both drugs not only were optimally fitted within a GSK-3β binding pocket via several attractive interactions with key amino acids but also exhibited potent in vitro enzymatic inhibitory activities of IC50 1.5 and 2.0 µM for naproxen and cromolyn, respectively. In vivo experiments illustrated that both drugs significantly reduced serum glucose and increased hepatic glycogen- and serum insulin levels in normal and type II diabetic Balb/c mice models. In obese animal model, both drugs exhibited significant reduction in mice weights, serum glucose, and resistin levels along with significant elevation in serum insulin, C-peptide, and adiponectin values. It can be concluded that naproxen and cromolyn are novel GSK-3β inhibitors and can help in management of diabetes and obesity.

Failure to generate bone marrow adipocytes does not protect mice from ovariectomy-induced osteopenia

A reciprocal association between bone marrow fat and bone mass has been reported in ovariectomized rodents, suggesting that bone marrow adipogenesis has a negative effect on bone growth and turnover balance. Mice with loss of function mutations in kit receptor (kit(W/W-v)) have no bone marrow adipocytes in tibia or lumbar vertebra. We therefore tested the hypothesis that marrow fat contributes to the development of osteopenia by comparing the skeletal response to ovariectomy (ovx) in growing wild type (WT) and bone marrow adipocyte-deficient kit(W/W-v) mice. Mice were ovx at 4 weeks of age and sacrificed 4 or 10 weeks post-surgery. Body composition was measured at necropsy by dual-energy X-ray absorptiometry. Cortical (tibia) and cancellous (tibia and lumbar vertebra) bone architecture were evaluated by microcomputed tomography. Bone marrow adipocyte size and density, osteoblast- and osteoclast-lined bone perimeters, and bone formation were determined by histomorphometry. Ovx resulted in an increase in total body fat mass at 10 weeks post-ovx in both genotypes, but the response was attenuated in the in kit(W/W-v) mice. Adipocytes were present in bone marrow of tibia and lumbar vertebra in WT mice and bone marrow adiposity increased following ovx. In contrast, marrow adipocytes were not detected in either intact or ovx kit(W/W-v) mice. However, ovx in WT and kit(W/W-v) mice resulted in statistically indistinguishable changes in cortical and cancellous bone mass, cortical and cancellous bone formation rate, and cancellous osteoblast and osteoclast-lined bone perimeters. In conclusion, our findings do not support a causal role for increased bone marrow fat as a mediator of ovx-induced osteopenia in mice.

Mast cells and vascular diseases

Mast cells are increasingly being recognized as effector cells in many cardiovascular conditions. Many mast-cell-derived products such as tryptase and chymase can, through their enzymic action, have detrimental effects on blood vessel structure while mast cell-derived mediators such as cytokines and chemokines can perpetuate vascular inflammation. Mice lacking mast cells have been developed and these are providing an insight into how mast cells are involved in cardiovascular diseases and, as knowledge increase, mast cells may become a viable therapeutic target to slow progression of cardiovascular disease.

Enhanced vascular chymase-dependent conversion of endothelin in the diabetic kidney

BACKGROUND

Diabetic nephropathy (DN) is associated with enhanced renal, plasma, and urinary endothelin (ET)-1 levels. Chymase cleaves Big ET-1 (1-38) to ET-1 (1-31), which is further cleaved by neutral endopeptidase to ET-1 (1-21). The current study tested the hypothesis that afferent arterioles (AA) of diabetic kidneys exhibit enhanced vasoconstrictor responses to chymase-dependent intrarenal ET formation compared to control kidneys.

METHODS

In situ juxtamedullary AA vasoconstrictor responses to the intrarenal conversion of Big ET-1 (1-38) to ET-1 (1-21) were performed in the absence and presence of chymase inhibition in type 2 diabetic db/db and control db/m mice studied under in vitro experimental conditions.

RESULTS

AA vasoconstrictor responses to Big ET-1 (1-38) were significantly enhanced in diabetic compared to control kidneys. In the presence of chymase inhibition (JNJ-18054478), AA vasoconstrictor responses of diabetic kidneys to Big ET-1 (1-38) were significantly less than the responses of control kidneys. AA diameters decreased similarly to ET-1 (1-21) in diabetic and control kidneys.

CONCLUSIONS

AA responses to the intrarenal conversion of Big ET-1 (1-38) to ET-1 in the absence of chymase enzymatic activity were significantly reduced in kidneys of diabetic compared to control mice, while the magnitude of the vasoconstriction to ET-1 (1-21) was not different. These data suggest that AA vasoconstriction produced by the chymase-dependent pathway is significantly greater in diabetic compared to control kidneys. We propose that intrarenal chymase-dependent ET-1 production contributes to the decline in function and progression to end-stage renal disease in patients with type 2 diabetes.

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

The mast cells are multi-effector cells with wide distribution in the different body parts and traditionally their role has been well-defined in the development of IgE-mediated hypersensitivity reactions including bronchial asthma. Due to the availability of genetically modified mast cell-deficient mice, the broadened pathophysiological role of mast cells in diverse diseases has been revealed. Mast cells exert different physiological and pathophysiological roles by secreting their granular contents, including vasoactive amines, cytokines and chemokines, and various proteases, including tryptase and chymase. Furthermore, mast cells also synthesize plasma membrane-derived lipid mediators, including prostaglandins and leukotrienes, to produce diverse biological actions. The present review discusses the pathophysiological role of mast cells in different diseases, including atherosclerosis, pulmonary hypertension, ischemia-reperfusion injury, male infertility, autoimmune disorders such as rheumatoid arthritis and multiple sclerosis, bladder pain syndrome (interstitial cystitis), anxiety, Alzheimer's disease, nociception, obesity and diabetes mellitus.