Nitric oxide: a regulator of mast cell activation and mast cell-mediated inflammation

Changes in exhaled volatile organic compounds following indirect bronchial challenge in suspected asthma

BACKGROUND

Inhaled mannitol provokes bronchoconstriction via mediators released during osmotic degranulation of inflammatory cells, and, hence represents a useful diagnostic test for asthma and model for acute attacks. We hypothesised that the mannitol challenge would trigger changes in exhaled volatile organic compounds (VOCs), generating both candidate biomarkers and novel insights into their origin.

METHODS

Participants with a clinical diagnosis of asthma, or undergoing investigation for suspected asthma, were recruited. Inhaled mannitol challenges were performed, followed by a sham challenge after 2 weeks in participants with bronchial hyper-responsiveness (BHR). VOCs were collected before and after challenges and analysed using gas chromatography-mass spectrometry.

RESULTS

Forty-six patients (mean (SD) age 52 (16) years) completed a mannitol challenge, of which 16 (35%) were positive, and 15 of these completed a sham challenge. Quantities of 16 of 51 identified VOCs changed following mannitol challenge (p<0.05), of which 11 contributed to a multivariate sparse partial least square discriminative analysis model, with a classification error rate of 13.8%. Five of these 16 VOCs also changed (p<0.05) in quantity following the sham challenge, along with four further VOCs. In patients with BHR to mannitol distinct postchallenge VOC signatures were observed compared with post-sham challenge.

CONCLUSION

Inhalation of mannitol was associated with changes in breath VOCs, and in people with BHR resulted in a distinct exhaled breath profile when compared with a sham challenge. These differentially expressed VOCs are likely associated with acute airway inflammation and/or bronchoconstriction and merit further investigation as potential biomarkers in asthma.

Isolation of Latilactobacillus curvatus with Enhanced Nitric Oxide Synthesis from Korean Traditional Fermented Food and Investigation of Its Probiotic Properties

Nitric oxide (NO) is a free radical associated with physiological functions such as blood pressure regulation, cardiovascular health, mitochondrial production, calcium transport, oxidative stress, and skeletal muscle repair. This study aimed to isolate Latilactobacillus curvatus strains with enhanced NO production from the traditional Korean fermented food, jangajji, and evaluate their probiotic properties for industrial purposes. When cells were co-cultured with various bacterial stimulants, NO production generally increased, and NO synthesis was observed in the range of 20-40 mg/mL. The selected strains of Lat. curvatus were resistant to acid and bile conditions and with variable effectiveness (1-14%) in adhering to Caco-2 cells. Most bacterial strains can inhibit the growth of various pathogens. In addition, they are capable of reducing cholesterol levels via assimilation of cholesterol at 10-50%. Among the selected NO synthases from Lat. curvatus strains, the strain JBCC38 showed the highest capacity to scavenge ABTS (30.1%) and DPPH radicals (39.4%). Moreover, these strains exhibited immunomodulatory properties. The production of TNF-α and IL-6 in the macrophages treated with various bacterial stimulants was induced in all the selected strains.

Molecular mechanisms of ferroptosis and its antitumor applications in natural products

Ferroptosis, an iron-dependent form of regulated cell death, results in lipid peroxidation of polyunsaturated fatty acids in the cell membrane, which is catalyzed by iron ions and accumulated to lethal levels. It is mechanistically distinct from other forms of cell death, such as apoptosis, pyroptosis, and necroptosis, so it may address the problem of cancer resistance to apoptosis and provide new therapeutic strategies for cancer treatment, which has been intensively studied over the past few years. Notably, considerable advances have been made in the antitumor research of natural products due to their multitargets and few side effects. According to research, natural products can also induce ferroptosis in cancer therapies. In this review we summarize the molecular mechanisms of ferroptosis, introduce the key regulatory genes of ferroptosis, and discuss the progress of natural product research in the field of ferroptosis to provide theoretical guidance for research on natural product-induced ferroptosis in tumors.

Dental Pulp Inflammation Initiates the Occurrence of Mast Cells Expressing the α1 and β1 Subunits of Soluble Guanylyl Cyclase

The binding of nitric oxide (NO) to heme in the β₁ subunit of soluble guanylyl cyclase (sGC) activates both the heterodimeric α₁β₁ and α₂β₁ isoforms of the enzyme, leading to the increased production of cGMP from GTP. In cultured human mast cells, exogenous NO is able to inhibit mast cell degranulation via NO-cGMP signaling. However, under inflammatory oxidative or nitrosative stress, sGC becomes insensitive to NO. The occurrence of mast cells in healthy and inflamed human tissues and the in vivo expression of the α₁ and β₁ subunits of sGC in human mast cells during inflammation remain largely unresolved and were investigated here. Using peroxidase and double immunohistochemical incubations, no mast cells were found in healthy dental pulp, whereas the inflammation of dental pulp initiated the occurrence of several mast cells expressing the α₁ and β₁ subunits of sGC. Since inflammation-induced oxidative and nitrosative stress oxidizes Fe²⁺ to Fe³⁺ in the β₁ subunit of sGC, leading to the desensitization of sGC to NO, we hypothesize that the NO- and heme-independent pharmacological activation of sGC in mast cells may be considered as a regulatory strategy for mast cell functions in inflamed human dental pulp.

EVALUATION OF THE EFFECT OF TOPICALLY APPLIED METHYLSULFONYLMETHANE AND THEIR COMBINATION WITH MINOXIDIL SOLUTION FOR IMPROVEMENT OF HAIR GROWTH IN MALE MICE

OBJECTIVE

The aim: The purpose of this research was to find out the effect of Methylsulfonylmethane in minimizing hair loss.

PATIENTS AND METHODS

Materials and methods: Twenty adult Wister Albino mice weighing 25-35g and aged 6-7 weeks were employed. Male mice's coat hairs on the dorsal skin were carefully clipped and then colored. Mice were randomly assigned into four groups, each with five animals: (1) Control group: Treated with D.W. (2), Minoxidil (5%) treated group (3), Methylsulfonylmethane (10%) treated group (4), Methylsulfonylmethane plus Minoxidil treated group.

RESULTS

Results: We found that the tissue level of 8-isoprastanein the groups receiving medication are considerably lower than in the control (D.W.). We also discovered that the serum tissue vascular endothelial growth factor levels in the groups receiving medication are considerably greater than those in the control (D.W.) groups. On the other hand, we discovered that hair growth, hair follicle expansion and hair follicle number are much higher in the groups receiving medication than in the control groups.

CONCLUSION

Conclusions: We concluded that MSM, through its antioxidant and anti-inflammatory properties, dramatically reduces hair loss in male mice.

The edematogenic effect of Micrurus lemniscatus venom is dependent on venom phospholipase A2 activity and modulated by non-neurogenic factors

Coral snakes mainly cause neurotoxic symptoms in human envenomation, but experimental studies have already demonstrated several pharmacological activities in addition to these effects. This investigation was carried out with the aim of evaluating (1) non-neurogenic mechanisms involved in the inflammatory response induced by Micrurus lemniscatus venom (MLV) in rat hind paws, (2) participation of PLA₂ in this response, and (3) neutralizing efficiency of commercial anti-elapid antivenom on edema. MLV promoted a rapid, significant increase in vascular permeability, influx of leukocytes, and disorganization of collagen bundles, as demonstrated by histological analysis. Several pretreatments were applied to establish the involvement of inflammatory mediators in MLV-induced edema (5 µg/paw). Treatment of animals with chlorpromazine reduced MLV-induced edema, indicating participation of TNF-α. However, the inefficiency of other pharmacological treatments suggests that eicosanoids, leukotrienes, and nitric oxide have no role in this type of edema formation. In contrast, PAF negatively modulates this venom-induced effect. MLV was recognized by anti-elapid serum, but this antivenom did not neutralize edema formation. Chemical modification of MLV with p-bromophenacyl bromide abrogated the phospholipase activity and markedly reduced edema, demonstrating PLA₂ participation in MLV-induced edema. In conclusion, the non-neurogenic inflammatory profile of MLV is characterized by TNF-α-mediated edema, participation of PLA₂ activity, and down-regulation by PAF. MLV induces an influx of leukocytes and destruction of collagen fibers at the site of its injection.

Regulatory Role of Nitric Oxide in Cutaneous Inflammation

Nitric oxide (NO), a signaling molecule, regulates biological functions in multiple organs/tissues, including the epidermis, where it impacts permeability barrier homeostasis, wound healing, and antimicrobial defense. In addition, NO participates in cutaneous inflammation, where it exhibits pro-inflammatory properties via the cyclooxygenase/prostaglandin pathway, migration of inflammatory cells, and cytokine production. Yet, NO can also inhibit cutaneous inflammation through inhibition of T cell proliferation and leukocyte migration/infiltration, enhancement of T cell apoptosis, as well as through down-regulation of cytokine production. Topical applications of NO-releasing products can alleviate atopic dermatitis in humans and in murine disease models. The underlying mechanisms of these discrepant effects of NO on cutaneous inflammation remain unknown. In this review, we briefly review the regulatory role of NO in cutaneous inflammation and its potential, underlying mechanisms.

Candidalysin, a Virulence Factor of Candida albicans, Stimulates Mast Cells by Mediating Cross-Talk Between Signaling Pathways Activated by the Dectin-1 Receptor and MAPKs

PURPOSE

Although mast cells (MCs) modulate the activity of effector cells during Candida albicans infection, their role in the pathogenesis of candidiasis remains unclear. Candidalysin, a C. albicans-derived peptide toxin, is a crucial factor in fungal infections. We aimed to investigate the effect of candidalysin on MC activation and the underlying molecular mechanism.

METHODS

Serum from candidalysin-immunized mice was used to measure candidalysin expression in patients infected with C. albicans. MC degranulation and migration were evaluated by β-hexosaminidase release assay and chemotaxis assay, respectively. EIA and ELISA were used to evaluate the production of eicosanoids and cytokines/chemokines, respectively. The production of nitric oxide (NO) was measured with a DAF-FM diacetate kit, while reactive oxygen species (ROS) production was analyzed by flow cytometry. MAPK activation was evaluated by Western blotting.

RESULTS

We detected high candidalysin expression in the lesions of patients infected with C. albicans, and the MC number was increased in these lesions. LL-37 colocalized with MCs in the lesions of candidiasis patients. Candidalysin-enhanced MC accumulation in mice and treating LAD2 and HMC-1 cells with candidalysin induced their degranulation, migration, and production of pro- and anti-inflammatory cytokines/chemokines, eicosanoids, ROS, NO, and LL-37. Interestingly, C. albicans strains lacking candidalysin failed to induce MC activation. Moreover, candidalysin increased dectin-1 expression, and the inhibition of dectin-1 decreased MC activation. Downstream dectin-1 signaling involved the MAPK pathways.

CONCLUSION

The finding that candidalysin causes cutaneous MC activation may improve our understanding of the role of MCs in the pathology of cutaneous C. albicans infection.

The Complexity of Sesquiterpene Chemistry Dictates Its Pleiotropic Biologic Effects on Inflammation

Sesquiterpenes (SQs) are volatile compounds made by plants, insects, and marine organisms. SQ have a large range of biological properties and are potent inhibitors and modulators of inflammation, targeting specific components of the nuclear factor-kappaB (NF-κB) signaling pathway and nitric oxide (NO) generation. Because SQs can be isolated from over 1600 genera and 2500 species grown worldwide, they are an attractive source of phytochemical therapeutics. The chemical structure and biosynthesis of SQs is complex, and the SQ scaffold represents extraordinary structural variety consisting of both acyclic and cyclic (mono, bi, tri, and tetracyclic) compounds. These structures can be decorated with a diverse range of functional groups and substituents, generating many stereospecific configurations. In this review, the effect of SQs on inflammation will be discussed in the context of their complex chemistry. Because inflammation is a multifactorial process, we focus on specific aspects of inflammation: the inhibition of NF-kB signaling, disruption of NO production and modulation of dendritic cells, mast cells, and monocytes. Although the molecular targets of SQs are varied, we discuss how these pathways may mediate the effects of SQs on inflammation.

Emerging role of natural products in cancer immunotherapy

Cancer immunotherapy has become a new generation of anti-tumor treatment, but its indications still focus on several types of tumors that are sensitive to the immune system. Therefore, effective strategies that can expand its indications and enhance its efficiency become the key element for the further development of cancer immunotherapy. Natural products are reported to have this effect on cancer immunotherapy, including cancer vaccines, immune-check points inhibitors, and adoptive immune-cells therapy. And the mechanism of that is mainly attributed to the remodeling of the tumor-immunosuppressive microenvironment, which is the key factor that assists tumor to avoid the recognition and attack from immune system and cancer immunotherapy. Therefore, this review summarizes and concludes the natural products that reportedly improve cancer immunotherapy and investigates the mechanism. And we found that saponins, polysaccharides, and flavonoids are mainly three categories of natural products, which reflected significant effects combined with cancer immunotherapy through reversing the tumor-immunosuppressive microenvironment. Besides, this review also collected the studies about nano-technology used to improve the disadvantages of natural products. All of these studies showed the great potential of natural products in cancer immunotherapy.

Exhaled Nitric Oxide Level in Pharynx Angioedema

Airway inflammation is related to increased nitric oxide production. It can be assessed noninvasively with exhaled nitric oxide measurement. As airway inflammation was supposed to be present in chronic urticaria and angioedema patients we hypothesized increased exhaled nitric oxide in this group. Twenty-six symptomatic chronic urticaria patients with an acute episode of pharynx angioedema (17 women and 9 men, median age 35) were included in the study group. None of the patients reported a history of asthma, allergic rhinitis or cigarette smoking. The control group consisted of 29 non-smoking healthy subjects (19 women and 10 men, median age 22) without any history of atopy. Exhaled nitric oxide measurement was performed in all subjects. Exhaled nitric oxide levels in the angioedema group did not differ statistically significantly from those detected in healthy subjects (15.5 ppb and 17.0 ppb respectively). Our results indicate the lack of airway inflammation in chronic urticaria patients with pharynx angioedema.

Targeted delivery of celastrol to glomerular endothelium and podocytes for chronic kidney disease treatment

The etiology of chronic kidney disease (CKD) is complex and diverse, which could be briefly categorized to glomerular- or tubular-originated. However, the final outcomes of CKD are mainly glomerular sclerosis, endothelial dysfunction and injury, and chronic inflammation. Thus, targeted delivery of drugs to the glomeruli in order to ameliorate glomerular endothelial damage may help alleviate CKD and help enrich our knowledge. The herb tripterygium wilfordii shows therapeutic effect on kidney disease, and celastrol (CLT) is one of its active ingredients but with strong toxicity. Therefore, based on the unique structure and pathological characteristics of the glomerulus, we designed a targeted delivery system named peptides coupled CLT-phospholipid lipid nanoparticles (PC-PLNs) to efficiently deliver CLT to damaged endothelial cells and podocytes in the glomerulus for CKD treatment and research. PC-PLNs could effectively inhibit inflammation, reduce endothelial damage, alleviate CKD severity, and reduce the toxicity of CLT. We also studied the mechanism of CLT in the treatment of nephropathy and found that CLT can increase the level of NO by increasing eNOS while inhibiting the expression of VCAM-1, thus provides an anti-inflammatory effect. Therefore, our study not only offered an efficient CKD drug formulation for further development, but also provided new medical knowledge about CKD.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary material (attached with all the supporting tables and figures mentioned in this work) is available in the online version of this article at 10.1007/s12274-021-3894-x.

Malaria-induced bacteremia as a consequence of multiple parasite survival strategies

Globally, malaria continues to be an enormous public health burden, with concomitant parasite-induced damage to the gastrointestinal (GI) barrier resulting in bacteremia-associated morbidity and mortality in both adults and children. Infected red blood cells sequester in and can occlude the GI microvasculature, ultimately leading to disruption of the tight and adherens junctions that would normally serve as a physical barrier to translocating enteric bacteria. Mast cell (MC) activation and translocation to the GI during malaria intensifies damage to the physical barrier and weakens the immunological barrier through the release of enzymes and factors that alter the host response to escaped enteric bacteria. In this context, activated MCs release Th2 cytokines, promoting a balanced Th1/Th2 response that increases local and systemic allergic inflammation while protecting the host from overwhelming Th1-mediated immunopathology. Beyond the mammalian host, recent studies in both the lab and field have revealed an association between a Th2-skewed host response and success of parasite transmission to mosquitoes, biology that is evocative of parasite manipulation of the mammalian host. Collectively, these observations suggest that malaria-induced bacteremia may be, in part, an unintended consequence of a Th2-shifted host response that promotes parasite survival and transmission. Future directions of this work include defining the factors and mechanisms that precede the development of bacteremia, which will enable the development of biomarkers to simplify diagnostics, the identification of therapeutic targets to improve patient outcomes and better understanding of the consequences of clinical interventions to transmission blocking strategies.

Light-induced nitric oxide release in the skin beyond UVA and blue light: Red & near-infrared wavelengths

Nitric oxide (NO) is omnipresent in the body and synthesized by 3 isoenzymes (nNOS, eNOS and iNOS), all detected in human skin. NO can be stored in a pool of compounds readily converted to NO following skin irradiation by UVR and blue light. This non-enzymatic (without NOS involvement) photolytic reaction mobilizes cutaneous stores of NO derivatives to the bloodstream, lowering blood pressure. However, with the likelihood of skin deleterious effects caused by UVR/blue light, safer wavelengths in the red/near-infrared (NIR) spectrum are becoming potential contenders to release cutaneous NO, possibly via NOS temperature-dependent effects. The use of red/NIR light to mobilize NO stores from the body's largest organ (the skin) is auspicious. This review focuses on UVR, blue, red, and NIR spectra and their capacity to release NO in human skin. PubMed and Google Scholar were used as article databases to find relevant publications related to this particular field.

Mechanisms Governing Anaphylaxis: Inflammatory Cells, Mediators, Endothelial Gap Junctions and Beyond

Anaphylaxis is a severe, acute, life-threatening multisystem allergic reaction resulting from the release of a plethora of mediators from mast cells culminating in serious respiratory, cardiovascular and mucocutaneous manifestations that can be fatal. Medications, foods, latex, exercise, hormones (progesterone), and clonal mast cell disorders may be responsible. More recently, novel syndromes such as delayed reactions to red meat and hereditary alpha tryptasemia have been described. Anaphylaxis manifests as sudden onset urticaria, pruritus, flushing, erythema, angioedema (lips, tongue, airways, periphery), myocardial dysfunction (hypovolemia, distributive or mixed shock and arrhythmias), rhinitis, wheezing and stridor. Vomiting, diarrhea, scrotal edema, uterine cramps, vaginal bleeding, urinary incontinence, dizziness, seizures, confusion, and syncope may occur. The traditional (or classical) pathway is mediated via T cells, Th2 cytokines (such as IL-4 and 5), B cell production of IgE and subsequent crosslinking of the high affinity IgE receptor (FcεRI) on mast cells and basophils by IgE-antigen complexes, culminating in mast cell and basophil degranulation. Degranulation results in the release of preformed mediators (histamine, heparin, tryptase, chymase, carboxypeptidase, cathepsin G and tumor necrosis factor alpha (TNF-α), and of de novo synthesized ones such as lipid mediators (cysteinyl leukotrienes), platelet activating factor (PAF), cytokines and growth factors such as vascular endothelial growth factor (VEGF). Of these, histamine, tryptase, cathepsin G, TNF-α, LTC₄, PAF and VEGF can increase vascular permeability. Recent data suggest that mast cell-derived histamine and PAF can activate nitric oxide production from endothelium and set into motion a signaling cascade that leads to dilatation of blood vessels and dysfunction of the endothelial barrier. The latter, characterized by the opening of adherens junctions, leads to increased capillary permeability and fluid extravasation. These changes contribute to airway edema, hypovolemia, and distributive shock, with potentially fatal consequences. In this review, besides mechanisms (endotypes) underlying IgE-mediated anaphylaxis, we also provide a brief overview of IgG-, complement-, contact system-, cytokine- and mast cell-mediated reactions that can result in phenotypes resembling IgE-mediated anaphylaxis. Such classifications can lead the way to precision medicine approaches to the management of this complex disease.

Involvement of tryptase-positive mast cells and angiogenesis in the growth of inflammatory odontogenic cysts

Inflammatory periapical lesions are characterized by infiltration of different immune cell types, the functions of which depend on an effective vascular network. This study aimed to evaluate the mast cells density (MCD) in inflamatory odontogenic cysts capsules concerning microvascular density (MVD), microvascular area (MVA), and microvascular perimeter (MVP), and correlate such findings with the type of lesion, intensity of the inflammatory infiltrate, and thickness of the epithelial lining. Twenty inflamatory dentigerous cysts (IDCs), twenty radicular cysts (RCs), and twenty residual radicular cysts (RRCs) were submitted to immunohistochemical analysis using anti-tryptase and anti-CD34 antibodies. RCs exhibited the highest MCD, MVD, MVA, and MVP indexes (p = < 0.001, p = 0.008, p = 0.003 and p = < 0.001, respectively), and lesions with inflammatory infiltrate grade III showed the highest MVD (p = 0.044). Considering epithelial thickness, a higher MVP index was identified in lesions with hyperplastic epithelium (p = 0.018). In IDCs, RCs, and RRCs, a strong positive correlation was observed between MVA and MVP (r = 0.950 and p = < 0.001; r = 0.914 and p = < 0.001; r = 0.713 and p = < 0.001, respectively). In IDCs, a moderate correlation was observed between MCD and both MVA and MVP (r = 0.660 and p = 0.002; r = 0.634 and p = 0.003, respectively). These results suggest that tryptase-positive mast cells might play an important role in the angiogenic activity of IDCs, while RCs had the highest indexes. Our findings also confirmed that the intensity of the inflammatory infiltrate and epithelial thickness influence angiogenesis.

Dietary Thiols: A Potential Supporting Strategy against Oxidative Stress in Heart Failure and Muscular Damage during Sports Activity

Moderate exercise combined with proper nutrition are considered protective factors against cardiovascular disease and musculoskeletal disorders. However, physical activity is known not only to have positive effects. In fact, the achievement of a good performance requires a very high oxygen consumption, which leads to the formation of oxygen free radicals, responsible for premature cell aging and diseases such as heart failure and muscle injury. In this scenario, a primary role is played by antioxidants, in particular by natural antioxidants that can be taken through the diet. Natural antioxidants are molecules capable of counteracting oxygen free radicals without causing cellular cytotoxicity. In recent years, therefore, research has conducted numerous studies on the identification of natural micronutrients, in order to prevent or mitigate oxidative stress induced by physical activity by helping to support conventional drug therapies against heart failure and muscle damage. The aim of this review is to have an overview of how controlled physical activity and a diet rich in antioxidants can represent a "natural cure" to prevent imbalances caused by free oxygen radicals in diseases such as heart failure and muscle damage. In particular, we will focus on sulfur-containing compounds that have the ability to protect the body from oxidative stress. We will mainly focus on six natural antioxidants: glutathione, taurine, lipoic acid, sulforaphane, garlic and methylsulfonylmethane.

Anti-Allergic Potential of Cinnamaldehyde via the Inhibitory Effect of Histidine Decarboxylase (HDC) Producing Klebsiella pneumonia

Allergy is an immunological disorder that develops in response to exposure to an allergen, and histamines mediate these effects via histidine decarboxylase (HDC) activity at the intracellular level. In the present study, we developed a 3D model of Klebsiella pneumoniae histidine decarboxylase (HDC) and analyzed the HDC inhibitory potential of cinnamaldehyde (CA) and subsequent anti-allergic potential using a bacterial and mammalian mast cell model. A computational and in vitro study using K. pneumonia revealed that CA binds to HDC nearby the pyridoxal-5'-phosphate (PLP) binding site and inhibited histamine synthesis in a bacterial model. Further study using a mammalian mast cell model also showed that CA decreased the levels of histamine in the stimulated RBL-2H3 cell line and attenuated the release of β-hexoseaminidase and cell degranulation. In addition, CA treatment also significantly suppressed the levels of pro-inflammatory cytokines TNF-α and IL-6 and the nitric oxide (NO) level in the stimulated mast cells. A gene expression and Western blotting study revealed that CA significantly downregulated the expressions of MAPKp38/ERK and its downstream pro-allergic mediators that are involved in the signaling pathway in mast cell cytokine synthesis. This study further confirms that CA has the potential to attenuate mast cell activation by inhibiting HDC and modifying the process of allergic disorders.

Halodule pinifolia (Seagrass) attenuated lipopolysaccharide-, carrageenan-, and crystal-induced secretion of pro-inflammatory cytokines: mechanism and chemistry

OBJECTIVES

The study aimed to explore the anti-inflammatory effect, underlying mechanism, and chemistry of Halodule pinifolia extract.

METHODS

The ethyl acetate (EHP) and methanol (MHP) extracts of Halodule pinifolia were screened for pro-inflammatory cytokine inhibition effect under various in vitro (LPSand crystal-induced inflammation) and in vivo models (LPS-induced endotoxaemia model, carrageenan-induced paw oedema model, and oxalate-induced renal nephropathy model of inflammation). The effect of EHP on the expression of inflammatory markers using western blot analysis (in vitro) was investigated. Chemical constituents of bioactive EHP were isolated through chromatography and characterised using NMR spectroscopy. Furthermore, EHP was standardised for rosmarinic acid, vanillic acid, and ethyl protocatechuate using HPLC. Also, total phytosterols, phenolic, and flavonoid content of EHP were determined by UV spectroscopy.

KEY FINDINGS

EHP was comparatively more effective than MHP in inhibiting cytokines secretions under LPS-induced in vitro models. Furthermore, EHP was screened under endotoxaemia in vivo model, EHP (250 mg/kg) reduced plasma IL-6, TNF-α, and IL-1β levels by 88.3%, 78.2%, and 74.5%, respectively. In the carrageenan-induced oedema model, EHP (200 mg/kg) reduced paw volume and release of TNF-α (69.3%) and IL-1β (43.1%). EHP (200 mg/kg) further controlled renal nephropathy by inhibiting plasma IL-1β and BUN levels. Also, a significant reduction of mRNA expressions of TNF-α and IL-1β and KIM-1 in renal tissues was observed. Through western blot, EHP was identified to regulate the expression of pro-form as well as mature-form of IL-1β and caspase-1. EHP constituted rosmarinic acid (RA), vanillic acid (VA), ethyl protocatechuate (EP), sitosterol, stigmasterol, campesterol, and dihydrobrassicasterol. It was determined that 4.6 mg/g of RA, 2.92 mg/g of VA, 0.76 mg/g of EP, 21.7 mg/g of total phenolics, 29.8 mg/g of total flavonoids, and 48.2 mg/g of total phytosterols were present in dry EHP. The presence of anti-inflammatory constituents such as RA, VA, and PE in EHP corroborated the in vitro and in vivo anti-inflammatory activity of EHP.

CONCLUSION

The anti-inflammatory property of EHP and its action through attenuation of pan-cytokines suggest that it can be developed into an oral pharmaceutical drug.

Nitric oxide and peroxynitrite trigger and enhance release of neutrophil extracellular traps

Despite great interest, the mechanism of neutrophil extracellular traps (NETs) release is not fully understood and some aspects of this process, e.g. the role of reactive nitrogen species (RNS), still remain unclear. Therefore, our aim was to investigate the mechanisms underlying RNS-induced formation of NETs and contribution of RNS to NETs release triggered by various physiological and synthetic stimuli. The involvement of RNS in NETs formation was studied in primary human neutrophils and differentiated human promyelocytic leukemia cells (HL-60 cells). RNS (peroxynitrite and nitric oxide) efficiently induced NETs release and potentiated NETs-inducing properties of platelet activating factor and lipopolysaccharide. RNS-induced NETs formation was independent of autophagy and histone citrullination, but dependent on the activity of phosphoinositide 3-kinases (PI3K) and myeloperoxidase, as well as selective degradation of histones H2A and H2B by neutrophil elastase. Additionally, NADPH oxidase activity was required to release NETs upon stimulation with NO, as shown in NADPH-deficient neutrophils isolated from patients with chronic granulomatous disease. The role of RNS was further supported by increased RNS synthesis upon stimulation of NETs release with phorbol 12-myristate 13-acetate and calcium ionophore A23187. Scavenging or inhibition of RNS formation diminished NETs release triggered by these stimuli while scavenging of peroxynitrite inhibited NO-induced NETs formation. Our data suggest that RNS may act as mediators and inducers of NETs release. These processes are PI3K-dependent and ROS-dependent. Since inflammatory reactions are often accompanied by nitrosative stress and NETs formation, our studies shed a new light on possible mechanisms engaged in various immune-mediated conditions.

Change in exhaled nitric oxide during peanut challenge is related to severity of reaction

BACKGROUND

Peanut allergy affects 3% of Australian children and has a higher risk of anaphylaxis than most food allergies. Predicting who is likely to develop anaphylaxis is still an inexact science. The fraction of exhaled nitric oxide (FeNO) shows promise as a biomarker involved in peanut allergy, as nitric oxide plays a role in inhibiting mast cell degranulation which is relevant in anaphylaxis, where mast cell degranulation plays a mediator role. The aim of this study was to assess the change in FeNO in children during peanut challenge.

METHODS

Thirty-six children aged from 5 to 17 years were recruited for open-labelled peanut challenge. Participants had skin prick test to peanut performed, and serum collected for Ara h2 specific IgE and peanut specific IgE. FeNO was measured by portable device (NIOX VERO) prior to and throughout the peanut challenge.

RESULTS

When grouped according to reaction type at peanut challenge (anaphylaxis, clinical allergy not anaphylaxis and tolerant), there were significant differences in the mean change in FeNO measurement between the anaphylaxis group and the clinical allergy, not anaphylaxis group (p = 0.005), and between the anaphylaxis group and tolerant group (p < 0.0001).

CONCLUSIONS

FeNO decreased more significantly in those who subsequently developed anaphylaxis than in those with clinical allergy, not anaphylaxis or negative peanut challenge (tolerance). As a bedside test that can be used in children, it has potential for further research into mechanisms of anaphylaxis in food allergy and potentially assists in predicting an imminent anaphylactic reaction in some patients.Trial registration ClinicalTrials.gov: PEAnut Anaphylaxis Predictors (PEAAP) NCT02424136.

Nitroxyl: A Novel Strategy to Circumvent Diabetes Associated Impairments in Nitric Oxide Signaling

Diabetes is associated with an increased mortality risk due to cardiovascular complications. Hyperglycemia-induced oxidative stress underlies these complications, leading to an impairment in endogenous nitric oxide (NO•) generation, together with reductions in NO• bioavailability and NO• responsiveness in the vasculature, platelets and myocardium. The latter impairment of responsiveness to NO•, termed NO• resistance, compromises the ability of traditional NO•-based therapeutics to improve hemodynamic status during diabetes-associated cardiovascular emergencies, such as acute myocardial infarction. Whilst a number of agents can ameliorate (e.g. angiotensin converting enzyme [ACE] inhibitors, perhexiline, statins and insulin) or circumvent (e.g. nitrite and sGC activators) NO• resistance, nitroxyl (HNO) donors offer a novel opportunity to circumvent NO• resistance in diabetes. With a suite of vasoprotective properties and an ability to enhance cardiac inotropic and lusitropic responses, coupled with preserved efficacy in the setting of oxidative stress, HNO donors have intact therapeutic potential in the face of diminished NO• signaling. This review explores the major mechanisms by which hyperglycemia-induced oxidative stress drives NO• resistance, and the therapeutic potential of HNO donors to circumvent this to treat cardiovascular complications in type 2 diabetes mellitus.

Stabilization of Perivascular Mast Cells by Endothelial CNP (C-Type Natriuretic Peptide)

OBJECTIVE

Activated perivascular mast cells (MCs) participate in different cardiovascular diseases. Many factors provoking MC degranulation have been described, while physiological counterregulators are barely known. Endothelial CNP (C-type natriuretic peptide) participates in the maintenance of vascular barrier integrity, but the target cells and mechanisms are unclear. Here, we studied whether MCs are regulated by CNP. Approach and Results: In cultured human and murine MCs, CNP activated its specific GC (guanylyl cyclase)-B receptor and cyclic GMP signaling. This enhanced cyclic GMP-dependent phosphorylation of the cytoskeleton-associated VASP (vasodilator-stimulated phosphoprotein) and inhibited ATP-evoked degranulation. To elucidate the relevance in vivo, mice with a floxed GC-B (Npr2) gene were interbred with a Mcpt5-Cre^TG line to generate mice lacking GC-B in connective tissue MCs (MC GC-B knockout). In anesthetized mice, acute ischemia-reperfusion of the cremaster muscle microcirculation provoked extensive MC degranulation and macromolecule extravasation. Superfusion of CNP markedly prevented MC activation and endothelial barrier disruption in control but not in MC GC-B knockout mice. Notably, already under resting conditions, such knockout mice had increased numbers of degranulated MCs in different tissues, together with elevated plasma chymase levels. After transient coronary occlusion, their myocardial areas at risk and with infarction were enlarged. Moreover, MC GC-B knockout mice showed augmented perivascular neutrophil infiltration and deep vein thrombosis in a model of inferior vena cava ligation.

CONCLUSIONS

CNP, via GC-B/cyclic GMP signaling, stabilizes resident perivascular MCs at baseline and prevents their excessive activation under pathological conditions. Thereby CNP contributes to the maintenance of vascular integrity in physiology and disease.

Dual Role of Toll-like Receptors in Human and Experimental Asthma Models

Asthma is a chronic airway inflammatory disease that is influenced by the interplay between genetic factors and exposure to environmental allergens, microbes, or microbial products where toll-like receptors (TLRs) play a pivotal role. TLRs recognize a wide range of microbial or endogenous molecules as well as airborne environmental allergens and act as adjuvants that influence positively or negatively allergic sensitization. TLRs are qualitatively and differentially expressed on hematopoietic and non-hematopoietic stromal or structural airway cells that when activated by TLRs agonists exert an immune-modulatory role in asthma development. Therefore, understanding mechanisms and pathways by which TLRs orchestrate asthma outcomes may offer new strategies to control the disease. Here, we aim to review and critically discuss the role of TLRs in human asthma and murine models of allergic airway inflammation, highlighting the complexity of TLRs function in development, exacerbation, or control of airway allergic inflammation.

Synthesis and in vitro evaluation of homoisoflavonoids as potent inhibitors of nitric oxide production in RAW-264.7 cells

Syntheses of natural homoisoflavonoids, (±)-portulacanones A-C (4, 8 and 9), portulacanone D (6), isolated from Portulaca oleracea L. (POL) and their derivatives (3, 5 and 7) have been achieved for the first time along with the synthesis of known derivatives (1 and 2) and their in vitro inhibitory effect against NO production in LPS-induced RAW-264.7 macrophages was evaluated as an indicator of anti-inflammatory activity. All the compounds tested had a concentration-dependent inhibitory effect on NO production by RAW-264.7 macrophages without obvious cytotoxicity. Compounds 3 (97.2% at 10 μM; IC₅₀ = 1.26 µM) followed by 6 (portulacanone D) (92.5% at 10 μM; IC₅₀ = 2.09 µM), 1 (91.4% at 10 μM; IC₅₀ = 1.75 µM) and 7 (83.0% at 10 μM; IC₅₀ = 2.91 µM) were the most potent from the series. This finding was further correlated with the suppressed expression of iNOS induced by LPS. Our promising preliminary results may provide the basis for the assessment of compound 3 as a lead structure for a NO production-targeted anti-inflammatory drug development and also could support the usefulness of POL as a folklore medicinal plant in the treatment of inflammatory diseases.

Alginate oligosaccharide enhances intestinal integrity of weaned pigs through altering intestinal inflammatory responses and antioxidant status

Alginate oligosaccharide (AOS), prepared from depolymerised alginate, a natural polysaccharide occurring in the cell walls of brown algae, provides beneficial effects for intestinal health. However, the underlying mechanisms by which AOS supplementation maintains the intestinal integrity of weaned pigs remain obscure. Here, we aimed to determine how AOS modulates the intestinal integrity of weaned pigs. Twenty-four weaned pigs were assigned to two treatments: a control group (basal diet) and an AOS group (the basal diet supplemented with 100 mg kg-1 AOS). On day 15, eight pigs per treatment were randomly selected and sacrificed for serum and intestinal samples. We observed that AOS supplementation enhanced the intestinal integrity, as evidenced by the increased (P < 0.05) intestinal occludin protein abundance. Compared to the control group, AOS ingestion both elevated (P < 0.05) the jejunal and ileal catalase activity and decreased (P < 0.05) the duodenal and jejunal tumour necrosis factor-α concentration and mast cell tryptase expression. Furthermore, AOS down-regulated (P < 0.05) the duodenal toll-like receptor 4 (TLR4) and its down-stream signals, myeloid differentiation factor 88 (MyD88), interleukin-1 receptor-associated kinase 1 (IRAK1) and tumour necrosis factor receptor-associated factor 6 (TRAF6) mRNA levels, as well as jejunal nucleotide-binding oligomerisation domain protein 1 (NOD1) and its adaptor molecule, receptor-interacting serine/threonine-protein kinase 2 (RIPK2), mRNA levels. Additionally, phospho-nuclear factor-κB (p-NF-κB) p65 protein abundance in the duodenum and jejunum was down-regulated (P < 0.05) following AOS supplementation. According to the above results, the enhanced intestinal integrity in AOS-supplemented pigs appears to be associated with the elevated antioxidant capacity and the reduced mast cell degranulation, as well as the inhibited pro-inflammatory cytokines production via inhibiting the TLR4/NF-κB and NOD1/NF-κB signalling pathways.

Therapeutic-Gas-Responsive Hydrogel

Nitric oxide (NO) is a crucial signaling molecule with various functions in physiological systems. Due to its potent biological effect, the preparation of responsive biomaterials upon NO having temporally transient properties is a challenging task. This study represents the first therapeutic-gas (i.e., NO)-responsive hydrogel by incorporating a NO-cleavable crosslinker. The hydrogel is rapidly swollen in response to NO, and not to other gases. Furthermore, the NO-responsive gel is converted to enzyme-responsive gels by cascade reactions from an enzyme to NO production for which the NO precursor is a substrate of the enzyme. The application of the hydrogel as a NO-responsive drug-delivery system is proved here by revealing effective protein drug release by NO infusion, and the hydrogel is also shown to be swollen by the NO secreted from the cultured cells. The NO-responsive hydrogel may prove useful in many applications, for example drug-delivery vehicles, inflammation modulators, and as a tissue scaffold.

Methylsulfonylmethane: Applications and Safety of a Novel Dietary Supplement

Methylsulfonylmethane (MSM) has become a popular dietary supplement used for a variety of purposes, including its most common use as an anti-inflammatory agent. It has been well-investigated in animal models, as well as in human clinical trials and experiments. A variety of health-specific outcome measures are improved with MSM supplementation, including inflammation, joint/muscle pain, oxidative stress, and antioxidant capacity. Initial evidence is available regarding the dose of MSM needed to provide benefit, although additional work is underway to determine the precise dose and time course of treatment needed to provide optimal benefits. As a Generally Recognized As Safe (GRAS) approved substance, MSM is well-tolerated by most individuals at dosages of up to four grams daily, with few known and mild side effects. This review provides an overview of MSM, with details regarding its common uses and applications as a dietary supplement, as well as its safety for consumption.

Anti-inflammatory activity of highly oxygenated terpenoids from Achillea biebersteinii Afan

In continuation of our chemical investigation on some medicinal plants of the genus Achillea, chromatographic investigation of the methylene chloride/methanol (1:1) extract of the air-dried aerial part of Achillea biebersteinii Afan. (family Asteraceae) afforded a new natural monoterpene (2), in addition to two known sesquiterpenes (3 and 4). Compound 1 was isolated as light needle crystals. Structures were established on the basis of MS and NMR spectroscopic (1H, 13C, 1H-1H correlation spectroscopy, heteronuclear multiple-quantum coherence and heteronuclear multiple-bond correlation) data and in case of compound 1 were confirmed by X-ray analysis. All isolated compounds were examined for their anti-inflammatory activity to inhibit lipopolysaccharide-induced NO production in RAW264.7 macrophage cells. Compounds 3 and 4 produced a promising anti-inflammatory effect (76% and 80% inhibition, respectively). However, compounds 1 and 2 produced moderate inhibition of NO release recording a 41% and 36% inhibition of NO production, respectively.

Cellular Metabolomics Revealed the Cytoprotection of Amentoflavone, a Natural Compound, in Lipopolysaccharide-Induced Injury of Human Umbilical Vein Endothelial Cells

Amentoflavone is one of the important bioactive flavonoids in the ethylacetate extract of “Cebaiye”, which is a blood cooling and hematostatic herb in traditional Chinese medicine. The previous work in our group has demonstrated that the ethylacetate extract of Cebaiye has a notable antagonistic effect on the injury induced by lipopolysaccharide (LPS) to human umbilical vein endothelial cells (HUVECs). The present investigation was designed to assess the effects and possible mechanism of cytoprotection of amentoflavone via metabolomics. Ultra-performance liquid chromatography/quadrupole time of flight-mass spectrometry (UPLC/QTOF-MS) coupled with multivariate data analysis was used to characterize the variations in the metabolites of HUVECs in response to exposure to LPS and amentoflavone treatment. Seven putative metabolites (glycine, argininosuccinic acid, putrescine, ornithine, spermidine, 5-oxoproline and dihydrouracil) were discovered in cells incubated with LPS and/or amentoflavone. Functional pathway analysis uncovered that the changes of these metabolites related to various significant metabolic pathways (glutathione metabolism, arginine and proline metabolism, β-alanine metabolism and glycine, serine and threonine metabolism), which may explain the potential cytoprotection function of amentoflavone. These findings also demonstrate that cellular metabolomics through UPLC/QTOF-MS is a powerful tool for detecting variations in a range of intracellular compounds upon toxin and/or drug exposure.

Acetaminophen Attenuates House Dust Mite-Induced Allergic Airway Disease in Mice

Epidemiologic evidence suggests that N-acetyl-para-aminophenol (APAP) may play a role in the pathogenesis of asthma, likely through pro-oxidant mechanisms. However, no studies have investigated the direct effects of APAP on the development of allergic inflammation. To determine the likelihood of a causal relationship between APAP and asthma pathogenesis, we explored the effects of APAP on inflammatory responses in a murine house dust mite (HDM) model of allergic airway disease. We hypothesized that APAP would enhance the development of HDM-induced allergic inflammation. The HDM model consisted of once daily intranasal instillations for up to 2 weeks with APAP or vehicle administration 1 hour prior to HDM during either week 1 or 2. Primary assessment of inflammation included bronchoalveolar lavage (BAL), cytokine expression in lung tissue, and histopathology. Contrary to our hypothesis, the effects of HDM treatment were substantially diminished in APAP-treated groups compared with controls. APAP-treated groups had markedly reduced airway inflammation: including decreased inflammatory cells in the BAL fluid, lower cytokine expression in lung tissue, and less perivascular and peribronchiolar immune cell infiltration. The anti-inflammatory effect of APAP was not abrogated by an inhibitor of cytochrome P450 (P450) metabolism, suggesting that the effect was due to the parent compound or a non-P450 generated metabolite. Taken together, our studies do not support the biologic plausibility of the APAP hypothesis that APAP use may contribute to the causation of asthma. Importantly, we suggest the mechanism by which APAP modulates airway inflammation may provide novel therapeutic targets for asthma.

Expression of inducible nitric oxide synthase in mast cells contributes to the regulation of inflammatory cytokines in irritable bowel syndrome with diarrhea

BACKGROUND

Nitric oxide (NO) and mast cells (MCs) are possibly involved in the development of irritable bowel syndrome (IBS), but details on their role and interactions still remain undetermined. We aimed to investigate the expression of inducible NO synthase (iNOS) in MCs of the colon of IBS with diarrhea (IBS-D), and elucidated a potential role of NO in the differential regulation of cytokines in MCs.

METHODS

Colonic mucosal biopsies of 19 IBS-D patients and 16 healthy controls were collected. The expression of tryptase and iNOS was investigated by immunohistochemistry, Western blotting, and real-time PCR. Effects of NO on the expression of cytokines in rat bone marrow MCs (BMMCs) were examined using a cytokine array by NG-nitro-l-arginine methyl ester (L-NAME) treatment.

KEY RESULTS

Immunohistochemistry for tryptase revealed an increase in number of MCs with extensive iNOS expression in the colonic mucosa of IBS-D. Tryptase, iNOS and interleukin (IL)-1β mRNA and protein levels were upregulated in IBS-D compared with healthy controls. Specifically, a positive correlation between tryptase and iNOS protein expression was observed in the colon of IBS-D (r = 0.667, p < 0.05). Supernatant from IBS-D increased iNOS expression in BMMCs. Antibody array showed that agrin, beta-nerve growth factor, fractalkine, granulocyte-macrophage colony-stimulating factor, IL-1β, IL-1R6, IL-13, leptin, tumor necrosis factor alpha were suppressed, and cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2α, CINC-3, monocyte chemotactic protein-1, matrix metalloproteinase-8 were strongly produced in L-NAME treated BMMCs, comparable to levels in the control group.

CONCLUSIONS & INFERENCES

Our findings provide new evidence that NO is able to regulate many cytokines in MCs that may be involved in the development of IBS.

Composition and anti-inflammatory effect of polysaccharides from Sargassum horneri in RAW264.7 macrophages

Sulfated polysaccharides extracted from brown marine algae have been shown to possess a variety of biological activities. We assessed the potential activity of the sulfated polysaccharide from Sargassum horneri (SP) and its isolated two major components (fraction-1 (F1) and fraction-2 (F2)), on anti-inflammatory activity in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. In the present study, analysis of polysaccharide chemical composition found that the constituent ratios of sulfate ester and fucose in SP and F1 were 4.95% vs 7.6%, and 4.48% vs 55.9%, respectively, suggesting that F1 may be a major sulfated polysaccharide containing fucose. Meanwhile, our findings demonstrated that TNF-α secretion levels were significantly (P<0.05) decreased by SP and F1 treatments in LPS-stimulated RAW264.7 cells in a dose-dependent manner under the preventive and repair experimental models. Pro-/anti-inflammatory (TNF-α/IL-10) cytokines secretion ratios by LPS-stimulated RAW264.7 macrophages were significantly (P<0.05) inhibited by SP and F1 treatments, particularly by F1 (at high dose, 200μg/ml). Moreover, NO release and iNOS activity were significantly (P<0.05) inhibited by F1. Collectively, the present study suggested that purified component, F1 from SP, had strong anti-inflammatory effects on LPS-stimulated RAW264.7 macrophages in the preventive and repair manner through inhibiting TNF-α secretion levels and NO release.

Cross talk between polysulfide and nitric oxide in rat peritoneal mast cells

The aim of this study was to define the effects of polysulfide on intracellular Ca(2+) concentration ([Ca(2+)]i) and the underlying machinery, especially from the hydrogen sulfide (H2S) and nitric oxide (NO) perspectives, in rat peritoneal mast cells. We found that a polysulfide donor, Na2S4, increased [Ca(2+)]i, which is both extracellular and intracellular Ca(2+) dependent. Intracellular Ca(2+) release induced by Na2S4 was attenuated by the addition of a ryanodine receptor blocker. A slow-releasing H2S donor, GYY4137, dose dependently increased [Ca(2+)]i that was independent from extracellular Ca(2+) influx. The GYY4137-induced [Ca(2+)]i release was partially attenuated in the presence of the ryanodine receptor blocker. Both polysulfide and H2S donors increased the intracellular NO levels in DAF-2-loaded mast cells, which were abolished by an NO scavenger, cPTIO. Inhibition of NO synthase (NOS) significantly abolished the polysulfide- or H2S-donor-induced [Ca(2+)]i elevation in the absence of extracellular Ca(2+) An NO donor, diethylamine (DEA) NONOate, increased [Ca(2+)]i in a concentration-dependent manner, in which both extracellular and intracellular Ca(2+) are associated. At higher concentrations, the DEA NONOate-induced [Ca(2+)]i increases were attenuated in the absence of extracellular Ca(2+) and by the addition of the ryanodine receptor blocker. H2S and NO dose dependently induced polysulfide production. Curiously, polysulfide, H2S, and NO donors had no effect on mast cell degranulation. Among synthases, cystathionine-γ-lyase, and neuronal NOS seemed to be the major H2S- and NO-producing synthases, respectively. These results indicate that polysulfide acts as a potential signaling molecule that regulates [Ca(2+)]i homeostasis in rat peritoneal mast cells via a cross talk with NO and H2S.

Protective Effects of Triphala on Dermal Fibroblasts and Human Keratinocytes

Human skin is body’s vital organ constantly exposed to abiotic oxidative stress. This can have deleterious effects on skin such as darkening, skin damage, and aging. Plant-derived products having skin-protective effects are well-known traditionally. Triphala, a formulation of three fruit products, is one of the most important rasayana drugs used in Ayurveda. Several skin care products based on Triphala are available that claim its protective effects on facial skin. However, the skin protective effects of Triphala extract (TE) and its mechanistic action on skin cells have not been elucidated in vitro. Gallic acid, ellagic acid, and chebulinic acid were deduced by LC-MS as the major constituents of TE. The identified key compounds were docked with skin-related proteins to predict their binding affinity. The IC₅₀ values for TE on human dermal fibroblasts (HDF) and human keratinocytes (HaCaT) were 204.90 ± 7.6 and 239.13 ± 4.3 μg/mL respectively. The antioxidant capacity of TE was 481.33 ± 1.5 mM Trolox equivalents in HaCaT cells. Triphala extract inhibited hydrogen peroxide (H₂O₂) induced RBC haemolysis (IC₅₀ 64.95 μg/mL), nitric oxide production by 48.62 ± 2.2%, and showed high reducing power activity. TE also rescued HDF from H₂O₂-induced damage; inhibited H₂O₂ induced cellular senescence and protected HDF from DNA damage. TE increased collagen-I, involucrin and filaggrin synthesis by 70.72 ± 2.3%, 67.61 ± 2.1% and 51.91 ± 3.5% in HDF or HaCaT cells respectively. TE also exhibited anti-tyrosinase and melanin inhibition properties in a dose-dependent manner. TE increased the mRNA expression of collagen-I, elastin, superoxide dismutase (SOD-2), aquaporin-3 (AQP-3), filaggrin, involucrin, transglutaminase in HDF or HaCaT cells, and decreased the mRNA levels of tyrosinase in B16F10 cells. Thus, Triphala exhibits protective benefits on skin cells in vitro and can be used as a potential ingredient in skin care formulations.

Coronary flow and oxidative stress during local anaphylactic reaction in isolated mice heart: the role of nitric oxide (NO)

The aim of this study was to assess the role of nitric oxide (NO) in cardiac anaphylaxis regarding changes in coronary reactivity and oxidative status of the mice heart. The animals were divided into two groups: experimental group (CBA, iNOS(-/-) mice) and control group: wild-type mice (CBA/H). The hearts of male mice (n = 24; 6-8 weeks old, body mass 20-25 g, 12 in each experimental group) were excised and retrogradely perfused according to the Langendorff technique at a constant perfusion pressure (70 cm H2O). Cardiac anaphylaxis was elicited by injection of solution (1 mg/1 ml) of ovalbumin into the aortic cannula. For the next 10 min, in intervals of 2 min (0-2, 2-4, 4-6, 6-8, 8-10 min) coronary flow (CF) rates were measured and samples of coronary effluent were collected. Markers of oxidative stress including index of lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS), NO measured in the form of nitrites (NO2(-)), superoxide anion radical (O2(-)), and hydrogen peroxide (H2O2) in the coronary venous effluent were assessed spectrophotometrically. After the ovalbumin challenge, CF was significantly lower in the wild mice group. NO and H2O2 release were significantly higher in iNOS(-/-) mice group. TBARS and O2(-) values did not vary significantly between wild and iNOS(-/-) mice groups. Our results indicate that coronary vasoconstriction during cardiac anaphylaxis does not necessarily depend on inducible nitric oxide synthase (iNOS)/NO activity and that iNOS/NO pathway may not be an only influential mediator of redox changes in this model of cardiac anaphylaxis.

Mast cells and histamine alter intestinal permeability during malaria parasite infection

Co-infections with malaria and non-typhoidal Salmonella serotypes (NTS) can present as life-threatening bacteremia, in contrast to self-resolving NTS diarrhea in healthy individuals. In previous work with our mouse model of malaria/NTS co-infection, we showed increased gut mastocytosis and increased ileal and plasma histamine levels that were temporally associated with increased gut permeability and bacterial translocation. Here, we report that gut mastocytosis and elevated plasma histamine are also associated with malaria in an animal model of falciparum malaria, suggesting a broader host distribution of this biology. In support of mast cell function in this phenotype, malaria/NTS co-infection in mast cell-deficient mice was associated with a reduction in gut permeability and bacteremia. Further, antihistamine treatment reduced bacterial translocation and gut permeability in mice with malaria, suggesting a contribution of mast cell-derived histamine to GI pathology and enhanced risk of bacteremia during malaria/NTS co-infection.

Optical imaging of fibrin deposition to elucidate participation of mast cells in foreign body responses

Mast cell activation has been shown to be an initiator and a key determinant of foreign body reactions. However, there is no non-invasive method that can quantify the degree of implant-associated mast cell activation. Taking advantage of the fact that fibrin deposition is a hallmark of mast cell activation around biomaterial implants, a near infrared probe was fabricated to have high affinity to fibrin. Subsequent in vitro testing confirmed that this probe has high affinity to fibrin. Using a subcutaneous particle implantation model, we found significant accumulation of fibrin-affinity probes at the implant sites as early as 15 min following particle implantation. The accumulation of fibrin-affinity probes at the implantation sites could also be substantially reduced if anti-coagulant - heparin was administered at the implant sites. Further studies have shown that subcutaneous administration of mast cell activator - compound 48/80 - prompted the accumulation of fibrin-affinity probes. However, implant-associated fibrin-affinity probe accumulation was substantially reduced in mice with mast cell deficiency. The results show that our fibrin-affinity probes may serve as a powerful tool to monitor and measure the extent of biomaterial-mediated fibrin deposition and mast cell activation in vivo.

Protective role of the endothelial isoform of nitric oxide synthase in ANG II-induced inflammatory responses in the kidney

In the present study, we examine the hypothesis that the nitric oxide (NO) produced by endothelial NO synthase (eNOS) plays a protective role in the development of ANG II-induced hypertension and renal injury by minimizing oxidative stress and the inflammation induced by TNF-α. Systolic blood pressure (SBP) and renal injury responses to chronic infusions of ANG II (via implanted minipumps) were evaluated for 2 wk in wild-type (WT) and in eNOS knockout mice (KO) cotreated with or without a superoxide (O2(-)) scavenger, tempol (400 mg/l in the drinking water), or a TNF-α receptor blocker, etanercept (5 mg/kg/day ip). In study 1, when ANG II was given at a dose of 25 ng/min, it increased mean SBP in WT mice (Δ36 ± 3 mmHg; n = 7), and this effect was attenuated in mice pretreated with tempol (Δ24 ± 3 mmHg; n = 6). In KO mice (n = 9), this dose of ANG II resulted in severe renal injury associated with high mortality. To avoid this high mortality in KO, study 2 was conducted with a lower dose of ANG II (10 ng/min) that increased SBP slightly in WT (Δ17 ± 7 mmHg; n = 6) but exaggeratedly in KO (Δ48 ± 12 mmHg, n = 6) associated with severe renal injury. Cotreatment with either tempol (n = 6) or etanercept (n = 6) ameliorated the hypertensive, as well as the renal injury responses in KO compared with WT. These data demonstrate a protective role for eNOS activity in preventing renal inflammatory injury and hypertension induced by chronic increases in ANG II.

Bronchodilatory effect of ethanolic extract of the leaves of Nyctanthes arbortristis

Background:

Nyctanthes arbortristis has been used in traditional medicine for the treatment of asthma and cough.

Aim:

In this study, bronchodilatory effect of ethanolic extract of the N. arbortristis was investigated under in vitro conditions. The concentration–response curve of the tracheal smooth muscle (TSM) to histamine was recorded in presence or absence of ethanolic extract and N^ω-nitro-l-arginine methyl ester (L-NAME). Dose–response effect of ethanolic extract on pre-constricted tissues was investigated. The ethanolic extract inhibited the histamine-induced maximum contractile responses of TSM (P < 0.001). Ethanolic extract also cause dose-dependent relaxation of TSM. These effects were reversed by L-NAME. Phytochemical analysis showed the presence of typical plant constituents. These results suggest the possible use of extract of the leaves of N. arbortristis as a bronchodilator in therapeutic treatment of asthma.

Malaria-associated L-arginine deficiency induces mast cell-associated disruption to intestinal barrier defenses against nontyphoidal Salmonella bacteremia

Coinfection with malaria and nontyphoidal Salmonella serotypes (NTS) can cause life-threatening bacteremia in humans. Coinfection with malaria is a recognized risk factor for invasive NTS, suggesting that malaria impairs intestinal barrier function. Here, we investigated mechanisms and strategies for prevention of coinfection pathology in a mouse model. Our findings reveal that malarial-parasite-infected mice, like humans, develop L-arginine deficiency, which is associated with intestinal mastocytosis, elevated levels of histamine, and enhanced intestinal permeability. Prevention or reversal of L-arginine deficiency blunts mastocytosis in ileal villi as well as bacterial translocation, measured as numbers of mesenteric lymph node CFU of noninvasive Escherichia coli Nissle and Salmonella enterica serotype Typhimurium, the latter of which is naturally invasive in mice. Dietary supplementation of malarial-parasite-infected mice with L-arginine or L-citrulline reduced levels of ileal transcripts encoding interleukin-4 (IL-4), a key mediator of intestinal mastocytosis and macromolecular permeability. Supplementation with L-citrulline also enhanced epithelial adherens and tight junctions in the ilea of coinfected mice. These data suggest that increasing L-arginine bioavailability via oral supplementation can ameliorate malaria-induced intestinal pathology, providing a basis for testing nutritional interventions to reduce malaria-associated mortality in humans.