Nitric oxide and asthmatic inflammation

Practical Guidelines for Asthma Management (PGAM): Digest edition

The international and national guidelines for asthma management are typically comprehensive and designed for respiratory specialists, making them less practical for primary care physicians who handle most asthma cases. Recognizing the need for more accessible guidelines, the Japan Asthma Society developed the Practical Guidelines for Asthma Management (PGAM). PGAM aims to provide a concise summary of key asthma management principles, increasing awareness, education, and support among nonspecialists and patients alike. It includes user-friendly tables and lists outlining common symptoms, triggers, diagnostic criteria, and basic management strategies, along with frequently encountered treatable traits and comorbidities. These elements are presented through simple, clinically relevant algorithms. A notable feature of PGAM is the "Basic Roadmap for Asthma Management," which outlines a clear sequence for patient assessment, diagnosis, and treatment from initial consultation onward, offering an easy-to-follow visual guide. Additionally, the guidelines include methods for assessing airway inflammation, enabling patient phenotyping and endotyping. This supports a personalized treatment approach, particularly with biologics, aimed at achieving clinical remission.

Dataset on the compounds from the leaves of Vietnamese Machilus thunbergii and their anti-inflammatory activity

Machilus thunbergii has a history of traditional applications including treating dyspepsia, apoplexy, headaches, abdominal pain, abdominal distension, and leg edema [1]. It is also employed for alleviating allergies, inflammation, pain relief, promoting blood circulation, addressing costal chondritis, and sinusitis [2]. Research into the chemical composition of M. thunbergii has revealed the presence of lignans, flavonoids, lactones, and essential oils [1,[3], [4], [5]. While some investigations have explored the inhibitory effects of extracts and lignan compounds from this species on NO production [6], [7], [8], there has been no research into the flavonoids isolated from this plant and their potential for inhibiting NO production, given our reachable referencing. The ethyl acetate (EtOAc) soluble fraction of M. thunbergii leaves was subjected to column chromatography (CC) using silica gel and Sephadex LH-20 for compound isolation. Nuclear magnetic resonance (NMR) data primarily facilitated the determination of isolated compound structures. Anti-inflammatory activity was evaluated against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in macrophage RAW264.7 cells. Anti-inflammatory activity-guided fractionation led to the isolation of twelve secondary metabolites (1-12). The compounds were identified as quercetin (1), kaempferol (2), rhamnetin (3), quercitrin (4), hyperoside (5), reynoutrin (6), guaijaverin (7), afzelin (8), astragalin (9), rutin (10), kaempferol-3-O-rutinoside (11), and rhamnetin-3-O-rutinoside (12). Compounds 3, 5, 6, 9, 11, and 12 were isolated from M. thunbergii for the first time. Evaluation against LPS-induced NO production in macrophage RAW264.7 cells showed that 1-3 exhibited potent inhibitory activity with IC50 values of 15.45, 25.44, and 19.82 µM, respectively. Compounds 4-9 demonstrated IC50 values ranging from 42.15 to 67.42 µM, while 10-12 exhibited inactivity (IC50 > 100 µM).

TEV/FEV₃ as a coherent metric of small airway dysfunction in childhood asthma

Background: Spirometry is an unrivalled tool for determining asthma and asthma severity. The ratio of forced expiratory volume (FEV) in 1 second (FEV₁) to forced vital capacity (FVC) and the forced expiratory flow between 25% and 75% of FVC (FEF_25-75) are well-known markers of airway obstruction, but they are limited by low reproducibility, particularly in children. In this study, we defined terminal expiration volume (TEV) as FEV in 3 seconds forced expiratory volume in 3 seconds (FEV₃) minus forced expiratory volume in 1 seconds (FEV₁) and investigate whether TEV/FEV₃ can function as a coherent marker to compensate for existing markers. Methods: This retrospective study comprised 980 children ages ≤ 18 years who underwent spirometry and the bronchial provocation testing. TEV/FEV₃ was compared with regard to asthma presence and severity. The findings were verified with an external validation group (n = 105). Results: FEV₃ was obtained in 837 children (85.4%). TEV/FEV₃ was significantly higher in patients with asthma than in patients who did not have asthma (17.1 ± 5.5 versus 12.0 ± 4.4, p < 0.001). External validation with 73 patients showed similar results (18.0 ± 5.9 in asthma versus 10.2 ± 5.1 in non-asthma, p < 0.001). The discriminatory power of TEV/FEV₃ for asthma was comparable with that of FEF_25-75 (p = 0.804). TEV/FEV₃ significantly increased with asthma severity (mild, 16.1 ± 5.4; moderate, 17.7 ± 5.4; severe, 22.0 ± 5.3; p < 0.001). For patients who could not achieve FEV₃, FEF_25-75 demonstrated no significant difference between mild and moderate asthma, and could not discriminate asthma or asthma severity. Conclusion: TEV/FEV₃ is a new metric that may help diagnose and determine asthma severity by using conventional spirometry by assessing small airway dysfunction. TEV/FEV₃ promotes a reassessment of the reliability of other spirometric parameters, particularly in young children. Caution is needed in interpreting the result of spirometry in children who cannot achieve FEV₃.

Korean Red Ginseng Ameliorates Allergic Asthma through Reduction of Lung Inflammation and Oxidation

Six-year-old red ginseng, which is processed from the whole ginseng root via steaming and drying, has been shown to have preventive effects such as antioxidative, anti-inflammatory, and immunomodulatory. In this study, we evaluated the therapeutic effects of Korean red ginseng (KRG) against ovalbumin (OVA)-induced allergic asthma and the underlying mechanisms involved. We injected 20 µg of OVA on days 0 and 14, and mice were challenged with aerosolized OVA via a nebulizer for 1 h on days 21, 22, and 23. KRG was administered at 100 and 300 mg/kg from days 18 to 23. The KRG-treated mice showed significant reductions in their airway hyperresponsiveness, production of reactive oxygen species (ROS), and the number of inflammatory cells compared with the OVA-treated mice. The levels of type 2 cytokines in the bronchoalveolar lavage fluid and expression of OVA-specific immunoglobulin E in the serum, which were elevated in the OVA group, were reduced in the KRG-treated groups. The pro-inflammatory factors, inducible nitric oxide synthase and nuclear factor kappa-light-chain-enhancer of activated B cells, were downregulated by the KRG administration in a dose-dependent manner. KRG effectively suppressed the inflammatory response by inhibiting ROS production. Our results suggest that KRG may have the potential to alleviate asthma.

The cholinergic anti-inflammatory pathway in humans: State-of-the-art review and future directions

The parasympathetic nervous system modulates inflammation through efferent vagus nerve signaling. Tracey (2002) termed this process as the cholinergic anti-inflammatory pathway (CAP). Interest in the potential practical use of this immune-modulatory process is increasing alongside increasing appreciation for the role of systemic inflammation in the etiology of somatic and psychological disease. A diverse literature exists providing expansive correlational evidence and some preliminary experimental evidence of the CAP in humans. However, so far this literature has not been well integrated and critically evaluated. This review describes the current state-of-the-art of research into vagus nerve driven parasympathetic control of inflammation in humans. Substantial limitations and gaps in the literature are identified, and promising directions for future research are highlighted.

Anti-Inflammatory Effects of 6-Methylcoumarin in LPS-Stimulated RAW 264.7 Macrophages via Regulation of MAPK and NF-κB Signaling Pathways

Persistent inflammatory reactions promote mucosal damage and cause dysfunction, such as pain, swelling, seizures, and fever. Therefore, in this study, in order to explore the anti-inflammatory effect of 6-methylcoumarin (6-MC) and suggest its availability, macrophages were stimulated with lipopolysaccharide (LPS) to conduct an in vitro experiment. The effects of 6-MC on the production and levels of pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α) and inflammatory mediators (nitric oxide (NO), prostaglandin E₂ (PGE₂)) in LPS-stimulated RAW 264.7 cells were examined. The results showed that 6-MC reduced the levels of NO and PGE₂ without being cytotoxic. In addition, it was demonstrated that the increase in the expression of pro-inflammatory cytokines caused by LPS stimulation, was decreased in a concentration-dependent manner with 6-MC treatment. Moreover, Western blot results showed that the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), which increased with LPS treatment, were decreased by 6-MC treatment. Mechanistic studies revealed that 6-MC reduced the phosphorylation of the mitogen-activated protein kinase (MAPK) family and IκBα in the MAPK and nuclear factor-kappa B (NF-κB) pathways, respectively. These results suggest that 6-MC is a potential therapeutic agent for inflammatory diseases that inhibits inflammation via the MAPK and NF-κB pathways.

Respiratory Syncytial Virus Infection Induces Expression of Inducible Nitric Oxide Synthase, CD3, and CD8 in Naturally Occurring Pneumonia in Lambs

Respiratory syncytial virus (RSV) is an RNA virus that belongs to the Pneumovirus genus of the Paramyxoviridae family. The aim of this study was to evaluate the expressions of inducible nitric oxide synthetase (iNOS), CD3 (pan T cells), and CD8 (cytotoxic T cells) in lamb lungs naturally infected with RSV using immunohistochemistry (IHC). For this purpose, 100 pneumonic and 10 control lung tissue samples were taken from lambs slaughtered in the slaughterhouse after macroscopic examination. The streptavidin– peroxidase method (ABC) was used for IHC staining, and it revealed RSV positivity in 18 of 100 examined lungs with pneumonia (18%). These positive cases were then immunostained for iNOS, CD3, and CD8, and compared to controls. In all these cases, an increase in iNOS expression (100%) was detected, the higher number of CD3+ T lymphocytes was detected in 14 (78%) cases while CD8+ T lymphocytes were detected in five (28%) cases, only. Given the increase of iNOS immunoexpression in all RSV-positive cases and increase in the number of CD3+ T lymphocytes in most cases, it was concluded that iNOS and CD3+ T lymphocytes play an important role in the immune response in lamb pneumonia with naturally occurring RSV infection. With this study, the role of the mentioned markers was evaluated for the first time in lambs naturally infected with RSV.

Anti-Inflammatory Effects of 6,7-Dihydroxy-4-Methylcoumarin on LPS-Stimulated Macrophage Phosphorylation in MAPK Signaling Pathways

Coumarin derivatives, such as esculetin, have various physiological functions, including antioxidant, anti-inflammatory, antibacterial, antiviral, and anti-cancer. 6,7-Dihydroxy-4-methylcoumarin (6,7-DH-4MC) is a derivative of esculetin, and its anti-inflammatory effect and mechanism in macrophages have not been studied. In this study, the anti-inflammatory activity of 6,7-DH-4MC was evaluated by measuring the expression of inflammatory factors (NO and PGE2) and pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) in LPS-stimulated RAW 264.7 macrophages. The results revealed that 6,7-DH-4MC significantly reduced NO levels and PGE2 expression without inducing cytotoxicity; it was confirmed that the inhibition of NO and PGE2 expression was related to iNOS and COX-2 downregulation in response to 6,7-DH-4MC treatment. Moreover, 6,7-DH-4MC decreased the levels of pro-inflammatory cytokines, such as IL-1β and IL-6, in a dose-dependent manner. Mechanistic studies revealed reduced phosphorylation of ERK and p38-MAPK upon 6,7-DH-4MC treatment. Furthermore, the degradation of IκB-α and phosphorylation of NF-κB in cells treated with LPS were interrupted by 6,7-DH-4MC treatment. These results suggest that 6,7-DH-4MC is a potential therapeutic agent for inflammatory diseases. To the best of our knowledge, this is the first report demonstrating the anti-inflammatory effects of 6,7-DH-4MC in RAW 264.7 cells via MAPK and NF-κB signaling pathways.

Contributions of asthma, rhinitis and IgE to exhaled nitric oxide in adolescents

Exhaled nitric oxide fraction (F eNO) is an indicator of allergic airway inflammation. However, it is unknown how asthma, allergic rhinitis (AR) and allergic sensitisation relate to F eNO, particularly among adolescents and in overlapping conditions. We sought to determine the associations between asthma, AR, and aeroallergen immunoglobulin (Ig)E and F eNO in adolescents. We measured F eNO among 929 adolescents (aged 11-16 years) in Project Viva, an unselected prebirth cohort in Massachusetts, USA. We defined asthma as ever asthma physician diagnosis plus wheezing in the past year or taking asthma medications in the past month, AR as a physician diagnosis of hay fever or AR, and aeroallergen IgE as any IgE >0.35 IU·mL-1 among 592 participants who provided blood samples. We examined associations of asthma, AR and IgE with percent difference in F eNO in linear regression models adjusted for sex, race/ethnicity, age and height, maternal education and smoking during pregnancy, and household/neighbourhood demographics. Asthma (14%) was associated with 97% higher F eNO (95% CI 70-128%), AR (21%) with 45% higher F eNO (95% CI 28-65%), and aeroallergen IgE (58%) with 102% higher F eNO (95% CI 80-126%) compared to those without each condition, respectively. In the absence of asthma or AR, aeroallergen IgE was associated with 75% higher F eNO (95% CI 52-101), while asthma and AR were not associated with F eNO in the absence of IgE. The link between asthma and AR with F eNO is limited to those with IgE-mediated phenotypes. F eNO may be elevated in those with allergic sensitisation alone, even in the absence of asthma or AR.

Anticalin® proteins: from bench to bedside

INTRODUCTION

Anticalin proteins are engineered versions of lipocalins that constitute a novel class of clinical-stage biopharmaceuticals. The lipocalins exhibit a central β-barrel with eight antiparallel β-strands and an α-helix attached to its side. Four structurally variable loops at the open end of the β-barrel form a pronounced binding pocket, which can be reshaped to generate specificities toward diverse disease-relevant molecular targets.

AREAS COVERED

This article reviews the current status of Anticalin engineering, from the basic principles to the development of Anticalins with high target affinity and specificity via combinatorial protein design and directed evolution, including examples of Anticalin-based drug candidates under preclinical and clinical development.

EXPERT OPINION

Combinatorial gene libraries together with powerful molecular selection techniques have enabled the expansion of the natural ligand specificities of lipocalins from small molecules to peptides and proteins. This biomolecular concept has been validated by structural analyses of a series of Anticalin•target complexes. Promising Anticalin lead candidates have reached different preclinical and clinical development stages in the areas of (immuno)oncology, metabolic, and respiratory diseases, as antidotes to treat intoxications and as novel antibiotics. Thus, Anticalins offer an alternative to antibodies with promising and potentially superior features as next-generation biologics.

Nitric Oxide in Macrophage Immunometabolism: Hiding in Plain Sight

Nitric Oxide (NO) is a soluble endogenous gas with various biological functions like signaling, and working as an effector molecule or metabolic regulator. In response to inflammatory signals, immune myeloid cells, like macrophages, increase production of cytokines and NO, which is important for pathogen killing. Under these proinflammatory circumstances, called “M1”, macrophages undergo a series of metabolic changes including rewiring of their tricarboxylic acid (TCA) cycle. Here, we review findings indicating that NO, through its interaction with heme and non-heme metal containing proteins, together with components of the electron transport chain, functions not only as a regulator of cell respiration, but also a modulator of intracellular cell metabolism. Moreover, diverse effects of NO and NO-derived reactive nitrogen species (RNS) involve precise interactions with different targets depending on concentration, temporal, and spatial restrictions. Although the role of NO in macrophage reprogramming has been in evidence for some time, current models have largely minimized its importance. It has, therefore, been hiding in plain sight. A review of the chemical properties of NO, past biochemical studies, and recent publications, necessitates that mechanisms of macrophage TCA reprogramming during stimulation must be re-imagined and re-interpreted as mechanistic results of NO exposure. The revised model of metabolic rewiring we describe here incorporates many early findings regarding NO biochemistry and brings NO out of hiding and to the forefront of macrophages immunometabolism.

Understanding and Exploiting the Effect of Tuberculosis Antimicrobials on Host Mitochondrial Function and Bioenergetics

Almost 140 years after its discovery, tuberculosis remains the leading infectious cause of death globally. For half a century, patients with drug-sensitive and drug-resistant tuberculosis have undergone long, arduous, and complex treatment processes with several antimicrobials that primarily function through direct bactericidal activity. Long-term utilization of these antimicrobials has been well-characterized and associated with numerous toxic side-effects. With the prevalence of drug-resistant strains on the rise and new therapies for tuberculosis urgently required, a more thorough understanding of these antimicrobials is a necessity. In order to progress from the “one size fits all” treatment approach, understanding how these antimicrobials affect mitochondrial function and bioenergetics may provide further insight into how these drugs affect the overall functions of host immune cells during tuberculosis infection. Such insights may help to inform future studies, instigate discussion, and help toward establishing personalized approaches to using such antimicrobials which could help to pave the way for more tailored treatment regimens. While recent research has highlighted the important role mitochondria and bioenergetics play in infected host cells, only a small number of studies have examined how these antimicrobials affect mitochondrial function and immunometabolic processes within these immune cells. This short review highlights how these antimicrobials affect key elements of mitochondrial function, leading to further discussion on how they affect bioenergetic processes, such as glycolysis and oxidative phosphorylation, and how antimicrobial-induced alterations in these processes can be linked to downstream changes in inflammation, autophagy, and altered bactericidal activity.

Obesity, sedentary lifestyle, and exhaled nitric oxide in an early adolescent cohort

Fractional exhaled nitric oxide (FeNO) is a marker of airway inflammation that is well-characterized in allergic disease states. However, FeNO is also involved in nonallergic inflammatory and pulmonary vascular mechanisms or responses to environmental stimuli. We sought to determine the extent to which obesity or sedentary lifestyle is associated with FeNO in adolescents not selected on the basis of allergic disease. In Project Viva, a prebirth cohort study, we measured body mass index (BMI), skinfold thicknesses, waist circumference, body fat, hours watching television, hours of physical activity, and heart rate after exercise among 929 adolescents (median age, 12.9). We measured FeNO twice and averaged these as a continuous, log-transformed outcome. We performed linear regression models, adjusted for child age, sex, height, and race/ethnicity, maternal education and smoking during pregnancy, household income and smoking, and neighbourhood characteristics. In secondary analysis, we additionally adjusted for asthma. More than 2 hours spent watching TV was associated with 10% lower FeNO (95% confidence interval [CI]: -20, 0%). Higher body fat percentage was also associated with lower FeNO. After additional adjustment for asthma, teens who are underweight (BMI <5th %tile, 3%) had 22% lower FeNO (95%CI: -40, 2%) and teens who are overweight (BMI ≥85th %ile, 28%) had 13% lower FeNO (95%CI: -23, -2%). Each of these associations of lifestyle and body weight with lower FeNO were greater in magnitude after adjusting for asthma. In summary, sedentary lifestyle, high and low BMI were all associated with lower FeNO in this adolescent cohort.

Urinary arsenic concentration, airway inflammation, and lung function in the U.S. adult population

BACKGROUND

Inorganic arsenic (iAs) is ubiquitous in the environment and has been linked to lung cancer and a number of non-malignant lung disease in both adults and children. However, most studies were conducted in populations with higher arsenic exposure levels in drinking water and relatively little epidemiologic research evaluated the impacts of low levels iAs exposure on non-malignant lung disease among populations that are not primarily exposed to arsenic through drinking water.

OBJECTIVES

We assessed the associations of arsenic exposure with airway inflammation and lung function among U.S. adults aged 20-79 years using data from the National Health and Nutrition Examination Survey 2007-2012 cycles.

METHODS

Two measures of arsenic exposure, urinary total arsenic and dimethylarsonic acid (DMA), were used. We calibrated these two exposure measures by regressing their concentrations by arsenobetaine and extracting the residuals to calculate estimated total arsenic and estimated DMA. Arsenic exposures were modeled as log-transformed continuous variables as well as quartile categories. Fractional exhaled nitric oxide (FENO), an indicator of respiratory inflammation, was available for participants. For lung function, the best forced expiratory volume in the first one second (FEV₁), forced vital capacity (FVC), forced expiratory flow rate (FEF) 25-75%, their percent estimated values, ratios of FEV₁ to FVC, and FEF 25-75% to FVC were used (i.e. FEV₁/FVC and FEF/FVC). Weighted multivariable linear regression models, adjusted for potential confounders, were used to evaluate the association of arsenic exposure with airway inflammation and lung function overall, and among males and females.

RESULTS

Significant associations between arsenic exposure and increased airway inflammation were found. A two-fold increase in urinary total arsenic and DMA was associated with 23.87% (95% CI: 2.66, 49.46) and 14.05% (95% CI: 1.77, 27.81) higher levels of FENO, respectively. In addition, participants in the highest quartile of urinary total arsenic had FENO levels 8.49% (95% CI: 1.13, 16.39) higher than those in the lowest quartile. These associations were similar between males and females. Limited evidence was found for the association with respect to lung function and potential modification effect of sex.

CONCLUSIONS

Arsenic exposure was related to increased risk of airway inflammation but there is limited evidence of an association in relation to lung function. Future research conducted in populations with relatively lower exposure levels that are not primarily exposed to arsenic through drinking water is needed to confirm our findings.

Heart Rate Variability Biofeedback Does Not Substitute for Asthma Steroid Controller Medication

Despite previous findings of therapeutic effects for heart rate variability biofeedback (HRVB) on asthma, it is not known whether HRVB can substitute either for controller or rescue medication, or whether it affects airway inflammation. Sixty-eight paid volunteer steroid naïve study participants with mild or moderate asthma were given 3 months of HRVB or a comparison condition consisting of EEG alpha biofeedback with relaxing music and relaxed paced breathing (EEG+), in a two-center trial. All participants received a month of intensive asthma education prior to randomization. Both treatment conditions produced similar significant improvements on the methacholine challenge test (MCT), asthma symptoms, and asthma quality of life (AQOL). MCT effects were of similar size to those of enhanced placebo procedures reported elsewhere, and were 65% of those of a course of a high-potency inhaled steroid budesonide given to a sub-group of participants following biofeedback training. Exhaled nitric oxide decreased significantly only in the HRVB group, 81% of the budesonide effect, but with no significant differences between groups. Participants reported becoming more relaxed during practice of both techniques. Administration of albuterol after biofeedback sessions produced a large improvement in pulmonary function test results, indicating that neither treatment normalized pulmonary function as a potent controller medication would have done. Impulse oscillometry showed increased upper airway (vocal cord) resistance during biofeedback periods in both groups. These data suggest that HRVB should not be considered an alternative to asthma controller medications (e.g., inhaled steroids), although both biofeedback conditions produced some beneficial effects, warranting further research, and suggesting potential complementary effects. Various hypotheses are presented to explain why HRVB effects on asthma appeared smaller in this study than in earlier studies. Clinical Trial Registration NCT02766374.

Comparison of inducible nitric oxide synthase mRNA expression in different airway portions and association with nitric oxide parameters from patients with asthma

Background

Fractional exhaled nitric oxide concentration (FeNO) is widely used to support diagnosis and monitoring of bronchial asthma (BA). Tsoukias and George proposed a two‐compartment model (2CM) for assessing the alveolar concentration of NO, referred to as CANO(2CM), while Condorelli et al proposed a model based on the trumpet shape of the airway tree and axial diffusion (TMAD), referred to as CANO(TMAD). In addition, Högman et al proposed non‐linear model, referred to as CANO(non‐linear).

Objective

We examined associations between the expression of inducible nitric oxide synthase (iNOS) mRNA in airway cells (ACs) by bronchoscopy and NO‐parameters calculated by the three methods and identified which of them accurately reflected expression of iNOSmRNA from different airway portions.

Methods

We retrospectively analysed data of 18 patients with stable, mild‐moderate asthma, including 10 steroid‐naïve BA (snBA) patients. Samples were obtained from airway brushings and bronchoalveolar lavage (BAL). Expressions of iNOS protein in tissue samples were evaluated by immunostaining. The iNOSmRNA in ACs was measured by qPCR. NO‐parameters calculated by the three methods above and evaluated whether they were associated with iNOSmRNA in ACs derived from proximal (2nd carina), distal (10‐15th) airways and alveolar regions.

Results

Immunostaining revealed expression of iNOS proteins mainly in epithelial cells in the airways, while it was mainly expressed in macrophages in the alveolar region in the snBA group. The iNOSmRNA expression was increased in both proximal and distal ACs in the snBA group compared with steroid‐treated BA group (stBA). CANO(2CM) negatively associated with FEV₁ (%predicted) and also associated with iNOSmRNA in distal ACs significantly. However, CANO(TMAD) and CANO(non‐linear) showed no correlation with lung function nor iNOSmRNA expression in any portions of ACs.

Conclusions

These results suggested that CANO(2CM) reflected distal airway inflammation in steroid‐naïve asthma.

The medicinal uses, toxicities and anti-inflammatory activity of Polyalthia species (Annonaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Polyalthia is one of the largest and notable genera in Annonaceae family. Polyalthia species have been widely used in folklore medicine for the treatment of rheumatic fever, gastrointestinal ulcer and generalized body pain. Numerous in vitro and in vivo studies on Polyalthia Species have also corroborated the significant anti-inflammatory potential of its extracts and secondary metabolites.

AIM OF THE STUDY

This review is an attempt to assess the anti-inflammatory activity of Polyalthia species by giving critical appraisal and establishing evidences of their traditional uses. Moreover this review will highlight the lead compounds for future drug development that can serve as a potential anti-inflammatory drug with comparative efficacy and minimum side effects.

MATERIALS AND METHODS

An extensive literature review, focusing the anti-inflammatory potential of Polyalthia species was conducted using the following databases:PubMed, ScienceDirect, SpringerLink, Ovid, Scopus and ProQuest, as well as the locally available books, journals and relevant documents. The reference lists of retrieved papers were also searched for additional studies.

RESULTS

The Polyalthia species have shown significant anti-inflammatory activity through various mechanism of action. The most significant anti-inflammatory mechanism includes the inhibition of nuclear factor kappa B (NF-κB), prostaglandins (PGs), pro-inflammatory cytokines, inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS). The data suggests that hydroxycleroda-3,13-dien-15,16-olide and 16-oxocleroda-3,13-dien-15-oic acid, quercetin, rutin, spinasterol, α-spinasterol, goniothalamin and (-)-5-hydroxygoniothalamin are the most potent anti-inflammatory compounds from Polyalthia species with comparable IC₅₀ with positive controls.

CONCLUSIONS

Numerous pharmacological studies have supported the use of Polyalthia species against pain, rheumatic fever, haemorrhages and inflammation in traditional medicine. Flavonoids, diterpenoids, sterols and styrylpyrones from genus Polyalthia are the most significant class of compounds with potent anti-inflammatory activity. Secondary metabolites from these classes should be brought into further research to fill the gaps of knowledge in pharmacokinetics, pharmacodynamics, bioavailability, and toxicity in order to convert the pre-clinical results into clinical data for further investigation.

Hamad M, AlMajali IS, Daiyyah WA. The Phytochemical Analysisand Antimicrobial Activity of Pergulariato mentosa in North East Kingdome of Saudi Arabia KSA

The increment in numbers of antimicrobial resistant strains along with the scarcity of new targets for drug industry has forced scientists to investigate deeply in the natural resources for new compounds with antimicrobial activity. Pergularia tomentosa is a member of the Apocynaceae family found in a wide geographical region including the Gulf region, Africa, and the Middle East. It is used as a remedy for the treatment of skin sores, asthma, and bronchitis. Dried plants of Pergularia tomentosa were subjected to extraction by using a Soxhlet extractor process to obtain essential oil and characterized by HPLC- Mass Spectroscopy (GC-MS). The essential oil was evaluated for antibacterial activity against pathogenic microorganisms by well diffusion method and confirmed by microdilution method. Additionally, we measured the antioxidant activity of the extracts using DPPH reagent. Phytochemical analysis has revealed variation in compositions and concentrations of P. tomentosa constituents grown in Hail from other agricultural regions. The lowest MIC was recorded with ethyl acetate extract MIC of 6.25 mg/ml against S. typhi, whereas, the ethanolic extract had the broadest effective against the five strains with a MIC of 25 mg/ml. In conclusion, we summarize a variation between the phytochemical constituents of P. tomentosa plants grown in the district of Hail and other geographical regions. In addition, there are several natural phytocompounds with an antimicrobial activity could be a good target for the antimicrobial and antioxidants industry.

The effect of bronchodilation and spirometry on fractional exhaled nitric oxide (FeNO50), bronchial NO flux (JawNO) and alveolar NO concentration (CANO) in children and young adults

OBJECTIVE

Fractional exhaled nitric oxide (FeNO), bronchial nitric oxide (JawNO) and alveoar nitric oxide (CANO) are biomarkers of eosinophilic inflammation, usually measured simultaneously with spirometry and bronchodilation. Our aim was to investigate the effect of bronchodilation and spirometry on FeNO, CANO and JawNO in children and young adults with well-controlled asthma and in healthy volunteers.

METHODS

FeNO was measured in 95 subjects (62 controls, 33 asthmatics). CANO and JawNO were assessed in 41 of the subjects (35 healthy, 6 asthmatics.) Measurements were performed before spirometry (1), right after spirometry (2), 20 min after the first spirometry and bronchodilation (3), right after the post-bronchodilation spirometry (4) and 30 min after the last spirometry (5).

RESULTS

The presence of well-controlled asthma was not associated with different pattern of reaction after spirometry and bronchodilation. A statistically significant difference was observed only between FeNO4 and FeNO5, as well as between CANO1 and CANO3 (19.14 ± 1.68 vs 20.62 ± 1.85 ppb, p = 0.001 and 4.42 ± 0.40 vs 3.09±0.32 ppb, p = 0.001, respectively).

CONCLUSIONS

Spirometry and bronchodilation have an insignificant effect on FeNO and JawNO. Even if a slight change occurs in FeNO and JawNO, this does not modify clinician's decision and therapeutic strategy. CANO values (CANO1) are significantly decreased 20 min after spirometry and bronchodilation.

Ability of Exhaled Nitric Oxide to Discriminate for Airflow Obstruction Among Frequent Exacerbators of Clinically Diagnosed Asthma

OBJECTIVE

Fraction of exhaled nitric oxide (FE_NO) has been proposed as a non-invasive biomarker for allergic inflammation seen in asthma. Many asthmatics in clinical practice have never had spirometry and recent data report misdiagnoses in patients with physician diagnosed (PD) asthma. The aim of this study was to assess the ability of FE_NO to discriminate between those with and without airflow obstruction (AO) among patients with PD-asthma.

METHODS

Frequent exacerbators of PD-asthma (with 2 or more asthma exacerbations leading to emergency room visit or hospitalization within last 12 months) were enrolled. All patients underwent diagnostic evaluations including spirometry, FE_NO testing and serum immunoglobulin (IgE) and eosinophils. Serial spirometry and methacholine challenge testing (MCT) were performed as indicated. AO was defined by a decreased FEV1/FVC ratio (< 70% and/or < LLN), or a positive MCT.

RESULTS

Of the 222 patients with PD-asthma, AO was found in 136 (vs. 86 without AO). 81.6% of patients with AO and 66.2% without AO completed FE_NO testing. There was no significant difference in the mean FE_NO levels among patients with or without AO (40.8 vs. 30.4 ppb, P = 0.10). Likewise, there was no difference in the serum IgE levels and serum eosinophils.

CONCLUSIONS

Our analyses suggest that FE_NO levels do not help discriminate between those with and without AO in patients with PD-asthma. Patients who experience symptoms of asthma may have elevated FE_NO levels above the suggested cut points of 20-25 ppb. Objective confirmation of AO should be considered in all patients with PD-asthma, irrespective of FE_NO levels.

Oxidative damage of SP-D abolishes control of eosinophil extracellular DNA trap formation

The asthmatic airways are highly susceptible to inflammatory injury by air pollutants such as ozone (O₃ ), characterized by enhanced activation of eosinophilic granulocytes and a failure of immune protective mechanisms. Eosinophil activation during asthma exacerbation contributes to the proinflammatory oxidative stress by high levels of nitric oxide (NO) production and extracellular DNA release. Surfactant protein-D (SP-D), an epithelial cell product of the airways, is a critical immune regulatory molecule with a multimeric structure susceptible to oxidative modifications. Using recombinant proteins and confocal imaging, we demonstrate here that SP-D directly bound to the membrane and inhibited extracellular DNA trap formation by human and murine eosinophils in a concentration and carbohydrate-dependent manner. Combined allergic airway sensitization and O₃ exposure heightened eosinophilia and nos2 mRNA (iNOS) activation in the lung tissue and S-nitrosylation related de-oligomerisation of SP-D in the airways. In vitro reproduction of the iNOS action led to similar effects on SP-D. Importantly, S-nitrosylation abolished the ability of SP-D to block extracellular DNA trap formation. Thus, the homeostatic negative regulatory feedback between SP-D and eosinophils is destroyed by the NO-rich oxidative lung tissue environment in asthma exacerbations.

Both fractional exhaled nitric oxide and sputum eosinophil were associated with uncontrolled asthma

Background

Sputum eosinophil and fractional exhaled nitric oxide (FeNO), noninvasive biomarkers of local eosinophilic airway inflammation, can be used to assess asthma outcome. Nevertheless, the clinical application of the association between FeNO and sputum eosinophil is controversial. The aim of the study was to investigate the predictive relationship between FeNO and sputum eosinophil in uncontrolled asthmatic patients and the correlation between sputum eosinophil and FeNO in bronchial reversibility and bronchial hyperresponsiveness (BHR).

Methods

A total of 69 uncontrolled asthmatic patients were included in the study. All patients underwent a clinical assessment on the same day as follows: FeNO, spirometry with BHR or bronchodilator reversibility test and induced sputum in turn. Eosinophilic airway inflammation was defined as sputum eosinophil percentage (≥2.5%)/FeNO level (≥32 parts per billion [ppb]).

Results

FeNO level and sputum neutrophilic percentage were higher in the sputum eosinophilia group compared to those without (49 versus 27, p=0.011; 71.12 versus 87.67, p=0.012, respectively). Sputum eosinophil percentage was higher with raised FeNO level compared to those without (10.3% versus 2.75%, p=0.03). A significant correlation was observed between sputum eosinophil percentage and FeNO level (r=0.4016; p=0.0006). There were no significant relationships between sputum eosinophilic percentage and provocative dose (PD₂₀)/ΔFEV₁ (improvement in a forced expiratory volume in 1 second [FEV₁] after 400μg of salbutamol), FeNO levels and PD₂₀/ΔFEV₁. The FeNO level of 35.5 ppb was effective in assessing sputum eosinophilia, with a receiver operating characteristic area under curve (AUC) of 0.707 (p=0.011; 95% confidence interval [CI] 0.573–0.841), and 4.36% was the best diagnostic cutoff value of sputum eosinophil percentage for the FeNO level of 32 ppb (AUC 0.721; 95% CI 0.59–0.852).

Conclusion

FeNO level can accurately detect eosinophilic asthma but has limited value to assess noneosinophilic asthma in uncontrolled stage. Further studies are required to validate the use of FeNO level to determine an optimal cutoff for sputum eosinophilia that could be used in clinical practice.

Effect of a retinoid X receptor partial agonist on airway inflammation and hyperresponsiveness in a murine model of asthma

Background

Retinoid X receptors (RXRs) are members of the nuclear receptor (NR) superfamily that mediate signaling by 9-cis retinoic acid, a vitamin A (retinol) derivative. RXRs play key roles not only as homodimers but also as heterodimeric partners—e.g., retinoic acid receptors (RARs), vitamin D receptors (VDRs), liver X receptors (LXRs), and peroxisome proliferator-activated receptors (PPARs). The NR family was recently associated with allergic diseases, but the role of RXRs in allergen-induced airway responses is not well defined.

The goal of this study is to elucidate the role of RXRs in asthma pathogenesis and the potency of RXR partial agonist in the treatment of allergic airway inflammation and airway hyperresponsiveness using a murine model of asthma.

Methods

We investigated the effect of a novel RXR partial agonist (NEt-4IB) on the development of allergic airway inflammation and airway hyperresponsiveness (AHR) in a murine model of asthma. Balb/c mice were sensitized (days 0 and 14) and challenged (days 28–30) with ovalbumin (OVA), and airway inflammation and airway responses were monitored 48 h after the last OVA challenge. NEt-4IB was administered orally on days 25 to 32.

Results

Oral administration of NEt-4IB significantly suppressed AHR and inflammatory cell accumulation in the airways and attenuated the levels of TNF-α in the lung and IL-5, IL-13 and NO levels in bronchoalveolar lavage (BAL) fluid and the number of periodic acid Schiff (PAS)-positive goblet cells in lung tissue. Treatment with NEt-4IB also significantly suppressed NF-κB expression.

Conclusion

These data suggest that RXRs may be of crucial importance in the mechanism of allergic asthma and that the novel RXR partial agonist NEt-4IB may be a promising candidate for the treatment of allergic airway inflammation and airway hyperresponsiveness in a model of allergic asthma.

Flunisolide attenuates nitric oxide-induced DNA damage in rat trachea epithelial cells

In asthma the bronchial epithelium is highly abnormal, with various structural changes. As a consequence, the epithelium becomes an important source of inflammatory mediators that contribute to the ongoing inflammation and remodeling responses occurring in asthma. Compared with normal individuals, the fraction of exhaled nitric oxide (NO) is elevated in patients with asthma, and these levels have been shown to vary with disease activity. Thus, in asthma, epithelial cells may be exposed to large amounts of NO. Increased NO production is associated with the formation of various nitrosating species capable of promoting DNA damage. In this study we investigated the effect of NO on DNA of rat trachea epithelial cells in the presence or absence of flunisolide. Rat airway epithelial cells were prepared and incubated with the NO donor S-nitroso-L-glutathione monoethyl ester (GSNO-MEE). DNA damage was evaluated using single cell gel electrophoresis 'comet assay.' The parameters used as an index of DNA damage were tail length, tail intensity, and tail moment. Results of our study demonstrated that NO induced significant DNA damage in rat airway epithelial cells. Flunisolide in amounts of 11-110 mumol/L significantly reduced all the considered parameters indicating DNA damage. These data indicate that flunisolide may protect epithelial cells from the NO-mediated DNA damage. NO overproduction could contribute to epithelial injury in asthma, and flunisolide seems to attenuate this damage.

Genetic Deletion of β-Arrestin-2 and the Mitigation of Established Airway Hyperresponsiveness in a Murine Asthma Model

β-Arrestin-2 (βarr2) is a ubiquitously expressed cytosolic protein that terminates G protein-coupled receptor signaling and transduces G protein-independent signaling. We previously showed that mice lacking βarr2 do not develop an asthma phenotype when sensitized to, and challenged with, allergens. The current study evaluates if an established asthma phenotype can be mitigated by deletion of βarr2 using an inducible Cre recombinase. We sensitized and challenged mice to ovalbumin (OVA) and demonstrated that on Day (d) 24 the allergic asthma phenotype was apparent in uninduced βarr2 and wild-type (WT) mice. In a second group of OVA-treated mice, tamoxifen was injected on d24 to d28 to activate Cre recombinase, and OVA aerosol challenge was continued through d44. The asthma phenotype was assessed using lung mechanics measurements, bronchoalveolar lavage cell analysis, and histological assessment of mucin and airway inflammation. Compared with their respective saline-treated controls, OVA-treated WT mice and mice expressing the inducible Cre recombinase displayed a significant asthma phenotype at d45. Whereas tamoxifen treatment had no significant effect on the asthma phenotype in WT mice, it inhibited βarr2 expression and caused a significant reduction in airway hyper-responsiveness (AHR) in Cre-inducible mice. These findings suggest that βarr2 is actively required for perpetuation of the AHR component of the allergic asthma phenotype. Our finding that βarr2 participates in the perpetuation of AHR in an asthma model means that targeting βarr2 may provide immediate and potentially long-term relief from daily asthma symptoms due to AHR irrespective of inflammation.

Nitric oxide enhances Th9 cell differentiation and airway inflammation

Th9 cells protect hosts against helminthic infection but also mediate allergic disease. Here we show that nitric oxide (NO) promotes Th9 cell polarization of murine and human CD4⁺ T cells. NO de-represses the tumor suppressor gene p53 via nitrosylation of Mdm2. NO also increases p53-mediated IL-2 production, STAT5 phosphorylation and IRF4 expression, all essential for Th9 polarization. NO also increases the expression of TGFβR and IL-4R, pivotal to Th9 polarization. OVA-sensitized mice treated with an NO donor developed more severe airway inflammation. Transferred Th9 cells induced airway inflammation, which was exacerbated by NO and blocked by anti-IL-9 antibody. Nos2^−/− mice had less Th9 cells and developed attenuated eosinophilia during OVA-induced airway inflammation compared to wild-type mice. Our data demonstrate that NO is an important endogenous inducer of Th9 cells and provide a hitherto unrecognized mechanism for NO-mediated airway inflammation via the expansion of Th9 cells.

Reference ranges and determinant factors for exhaled nitric oxide in a healthy korean elderly population

Purpose

Exhaled nitric oxide (NO) is a useful non-invasive biomarker for asthma diagnosis; however, the literature suggests that exhaled NO levels may be affected by demographic factors. The present analysis investigated determinant factors that present exhaled NO reference levels for Korean elderly adults.

Methods

For reference levels, we analyzed the baseline data of healthy adult participants in the Ansung cohort. The fraction of exhaled NO (FeNO) was measured by NIOX MINO®. The characterization of the subjects was performed through structured questionnaires, spirometry, and methacholine challenge tests. To validate the diagnostic utility of the determined reference levels, asthma patients were recruited from medical institutions for FeNO measurement.

Results

A total of 570 healthy subjects were analyzed (mean age, 59.9±12.3; male, 37.0%) for reference levels. FeNO levels significantly correlated with weight, height, body mass index, atopy, or forced expiratory volume in 1 second % predicted by simple linear regression analysis. Multiple linear regression analysis identified gender as an independent determinant for FeNO levels; subsequently, the reference values for FeNO were 18.2±10.6 ppb (5th to 95th percentile, 6.0 to 37.4 ppb) for males and 12.1±6.9 ppb (5th to 95th percentile, 2.5 to 27.0 ppb) for females. The diagnostic utility of FeNO reference levels was validated by receiver operating curve analysis (area under curve, 0.900 for males and 0.885 for females) for diagnosing asthma. The optimal cutoff values for the prediction of asthma were 30.5 ppb for males and 20.5 ppb for females.

Conclusions

The current analysis presented reference ranges and the diagnostic utility of FeNO levels for asthma in Korean elderly adults.

Regulation of airway nucleotides in chronic lung diseases

The physiological relevance of the purinergic signaling network for airway defenses is emerging through cumulating reports of abnormal ATP and adenosine (ADO) levels in the airway secretions of patients with asthma, chronic pulmonary obstructive diseases, cystic fibrosis and idiopathic pulmonary fibrosis. The consequences for airway defenses range from abnormal clearance responses to the destruction of lung tissue by excessive inflammation. This chapter reviews the challenges of assessing airway purines in human subjects, and identifies the general trend in aberrant airway composition. Most diseases are associated with an accumulation of ATP and/or ADO in bronchoalveolar lavage, sputum or exhaled breadth condensate. Intriguing is the case of cystic fibrosis patients, which do not accumulate airway ADO, but its precursor, AMP. This observation launched the investigation of ectonucleotidases as target proteins for the correction of airway purine levels in chronic respiratory diseases. This chapter exposes the extensive rearrangement of the enzymatic network taking place in diseased airways, and identifies signaling pathways likely involved in the aberrant regulation of the airway purines.

Asthma: Gln27Glu and Arg16Gly polymorphisms of the beta2-adrenergic receptor gene as risk factors

Background

Asthma is caused by both environmental and genetic factors. The ADRB2 gene, which encodes the beta 2-adrenergic receptor, is one of the most extensively studied genes with respect to asthma prevalence and severity. The Arg16Gly (+46A > G) and Gln27Glu (+79C > G) polymorphisms in the ADRB2 gene cause changes in the amino acids flanking the receptor ligand site, altering the response to bronchodilators and the risk of asthma through complex pathways. The ADRB2 polymorphisms affect beta-adrenergic bronchodilator action and are a tool to identify at-risk populations.

Objective

To determine the frequency of these two polymorphisms in allergic asthma patients and healthy subjects and to correlate these data with the occurrence and severity of asthma.

Methods

Eighty-eight allergic asthma patients and 141 healthy subjects were included in this study. The ADRB2 polymorphisms were analyzed using the amplification-refractory mutation system – polymerase chain reaction (ARMS-PCR) technique. The statistical analysis was performed with the SPSS 21.0 software using the Fisher’s Exact and χ² tests.

Results

The ADRB2 polymorphisms were associated with asthma occurrence. The Arg16Arg, Gln27Gln and Gln27Glu genotypes were risk factors; the odds ratios were 6.782 (CI = 3.07 to 16.03), 2.120 (CI = 1.22 to 3.71) and 8.096 (CI = 3.90 to 17.77), respectively. For the Gly16Gly and Glu27Glu genotypes, the odds ratios were 0.312 (CI = 0.17 to 0.56) and 0.084 (CI = 0.04 to 0.17), respectively. The haplotype analysis showed that there were associations between the following groups: Arg16Arg-Gln27Gln (OR = 5.108, CI = 1.82 to 16.37), Gly16Gly-Glu27Glu (OR = 2.816, CI = 1.25 to 6.54), Arg16Gly-Gln27Glu (OR = 0.048, CI = 0.01 to 0.14) and Gly16Gly-Gln27Glu (OR = 0.1036, CI = 0.02 to 0.39). The polymorphism Gln27Glu was associated with asthma severity, as the Gln27Gln genotype was a risk factor for severe asthma (OR = 2.798, CI = 1.099 to 6.674) and the Gln27Glu genotype was a protective factor for mild (OR = 3.063, CI = 1.037 to 9.041) and severe (OR = 0.182, CI = 0.048 to 0.691) asthma.

Conclusions

The Arg16Gly and Gln27Glu polymorphisms in the ADRB2 gene are associated with asthma presence and severity.

Purification of surfactant protein D (SP-D) from pooled amniotic fluid and bronchoalveolar lavage

Surfactant protein SP-D is a multimeric collagenous lectin, called collectin. SP-D is a multifunctional, pattern recognition innate immune molecule, which binds in a calcium dependent manner to an array of carbohydrates and lipids, thus offering resistance to invading pathogens, allergen challenge, and pulmonary inflammation. SP-D is predominantly found in the endoplasmic reticulum of type 2 pneumocytes and in the secretory granules of Clara or non-ciliated bronchiolar cells. The highest expression of SP-D is observed in the distal airways and alveoli. There is also an extra pulmonary existence of SP-D. The common sources of native full-length human SP-D are bronchoalveolar lavage (BAL) washings from normal or preferably patients suffering from alveolar proteinosis who overproduce SP-D in the lungs. Amniotic fluid collected at the term during parturition is another reasonable source. Here, we describe a simple and rapid method of purifying native SP-D away from SP-A which is also present in the same source. We also describe procedures of expressing and purifying a recombinant fragment of human SP-D (rhSP-D) comprising trimeric neck and carbohydrate recognition domains that has been shown to have therapeutic effects in murine models of allergy and infection.

The fractional exhaled nitric oxide and serum high sensitivity C-reactive protein levels in cough variant asthma and typical bronchial asthma

BACKGROUND

Fractional exhaled nitric oxide (FeNO) is known to be a good marker of airway eosinophilic inflammation in bronchial asthma. Recently, serum high sensitivity C-reactive protein (hs-CRP) has been shown to be also useful to detect the airway inflammation.

METHODS

Newly diagnosed 90 cough variant asthma and 92 bronchial asthma patients were enrolled. FeNO, serum hs-CRP, pulmonary function tests, bronchial hyperresponsiveness, IgE and sputum eosinophils ratio were compared. Ninety healthy control subjects were set for FeNO and serum hs-CRP normal range reference. We have compared the clinical utilities of FeNO and serum hs-CRP to differentiate bronchial asthma and cough variant asthma.

RESULTS

FeNO was significantly higher in bronchial asthma (92.6 ± 85.5ppb) than in cough variant asthma (35.6 ± 43.3; p < 0.001) and both were significantly higher than normal range (18.0 ± 6.4, p < 0.001, respectively), and in differentiating between the two groups showed a sensitivity of 0.69 and a specificity of 0.73 at the cutoff value of 28 ppb. Serum hs-CRP did not differ significantly between bronchial asthma (723 ± 1162ng/ml) and cough variant asthma (558 ± 758) even if both were significantly higher than normal range (345 ± 401, p < 0.01 and p < 0.05 respectively).

CONCLUSIONS

FeNO is more useful than serum hs-CRP in differentiating patients with bronchial asthma from those with cough variant asthma, and healthy persons.

Therapeutic potential of curcumin in experimentally induced allergic rhinitis in guinea pigs

In the present experiments, the possible role of curcumin in ovalbumin induced allergic rhinitis in guinea pig model was investigated. Various allergic rhinitis symptoms viz sneezing, rubbing frequencies, lacrimation and nasal congestion at various humidity conditions as well as on repeated sensitization were studied. The biochemical changes like serum IgE, IL-4 and nitric oxide (NO) in nasal lavage and eosinophil peroxidase activity in nasal homogenates were determined in allergic rhinitis. Curcumin treatment significantly reduced the symptoms (sneezing, rubbing frequencies, lacrimation and nasal congestion) and improved the histopathological alterations (reduction in inflammatory cells infiltration) of nasal mucosa in allergic rhinitis. Furthermore, curcumin treatment prevented significantly elevation of serum IgE, IL-4, NO in nasal lavage and eosinophil peroxidase in nasal homogenate. In the present experimental findings, we suggest that curcumin is a promising anti-allergic agent that may be useful in the clinical management of allergic rhinitis.

Synthesis, preliminary structure-activity relationships, and in vitro biological evaluation of 6-aryl-3-amino-thieno[2,3-b]pyridine derivatives as potential anti-inflammatory agents

In our previous study, a series of 6-aryl-3-amino-thieno[2,3-b]pyridine derivatives exhibited potent antiproliferative activities and an unique hepatocellular carcinoma (HCC)-specific anticancer activity was also observed. In further anti-inflammatory research, thienopyridine derivative 1a showed potent inhibition of nitric oxide (NO) production. So a series of thienopyridine analogues of 1a were synthesized and evaluated for anti-inflammatory activities. The structure-activity relationships (SARs) revealed that the most potent analogues 1f and 1o were identified as potent inhibitors of NO production with IC50 values of 3.30 and 3.24 μM, respectively. These results suggest that these 6-aryl-3-amino-thieno[2,3-b]pyridine derivatives might potentially constitute a novel class of anti-inflammatory agents, which require further studies.

Fractional exhaled nitric oxide in Chinese children with asthma and allergies--a two-city study

Fractional exhaled nitric oxide (FeNO) is a non-invasive biomarker of eosinophilic airway inflammation. Our aim was to study associations between FeNO in Chinese children in two cities and asthma, asthmatic symptoms, rhinitis, eczema, and selected childhood and home environmental factors. A random sample of children in Shanghai (n = 187) and Taiyuan (n = 127), and additional randomly selected children reporting current wheeze (n = 115) were invited for FeNO measurements by NIOX MINO. A questionnaire survey was performed among all subjects (12-14 y) in 59 classes in Shanghai and 44 in Taiyuan. Associations were studied using multiple linear regression using 10log transformed FeNO data and mutual adjustment. The geometric mean FeNO in the random sample (GM ± GSD) was higher in Shanghai (16.2 ± 1.9 ppb) as compared to Taiyuan (12.8 ± 1.6 ppb) (P < 0.001). In the total material (n = 429), Shanghai residency (P = 0.001), male gender (P = 0.02), parental asthma/allergy (P = 0.04), doctors' diagnosed asthma (DDA) (P < 0.001) and current wheeze (P < 0.001) were associated with higher FeNO levels. In non-wheezers (n = 291), Shanghai residency (P = 0.007), male gender (P = 0.002), DDA (P = 0.04), current rhinitis (P = 0.004) and reported pollen/furry pet allergy (P = 0.04) were positively associated with FeNO. In wheezers (n = 138), DDA was the only significant factor (P = 0.009). In conclusion, male gender, current wheeze, DDA, parental asthma/allergy, current rhinitis, pollen/furry pet allergy can be independent determinants of increased FeNO. The lower level of FeNO in Taiyuan is in agreement with previous studies showing lower prevalence of asthma and allergy in Taiyuan as compared to Shanghai.

Rooperol, an inhibitor of cytokine synthesis, decreases the respiratory burst in human and rat leukocytes and macrophages

Luminol-enhanced chemiluminescence was measured in fresh whole human blood, or human neutrophils isolated from heparinized blood, human alveolar macrophages and rat alveolar macrophages stimulated with bacterial endotoxin (LPS). Tetraacetate esters of rooperol, a dicatechol showing anticytokine activity, added to cells simultaneously with LPS inhibited the respiratory burst. The effective concentrations of rooperol were in the range of 1-10 μM depending on cell type and corresponded well with inhibition of nitric oxide production by rat alveolar macrophages. Thus rooperol may reduce some effects of excessive phagocytic activity and inflammatory reaction but by quenching free radicals production may also diminish the resistance to bacterial infections.

IFN-γ production by allogeneic Foxp3+ regulatory T cells is essential for preventing experimental graft-versus-host disease

It is emerging that CD4+Foxp3+ regulatory T (Treg) cells can produce the proinflammatory cytokine IFN-γ when stimulated in a Th1 cytokine environment. In this study, we report that Foxp3+ Treg cells readily produced IFN-γ in vivo in a highly inflammatory model of graft-versus-host disease (GVHD) and during a Th1-dominated immune response to intracellular bacteria. Moreover, stimulation in vitro via TCR in the presence of IL-12 alone was sufficient to induce IFN-γ production by Treg cells in a dose-dependent manner. Transfer of donor Treg cells can prevent lethal GVHD; therefore, we used this model as a robust readout for in vivo Treg function. Interestingly, >50% of allogeneic donor, but not residual recipient Foxp3+ Treg cells produced IFN-γ after transplantation, suggesting that this cytokine production was alloantigen specific. These IFN-γ producers were stable Foxp3+ Treg cells because methylation analysis of the Foxp3 gene locus of transferred and reisolated Treg cells during GVHD showed a fully demethylated Treg-specific-demethylated region. Next, we addressed whether IFN-γ production was supporting or rather impairing the immunosuppressive function of Treg cells during GVHD. Blocking of IFN-γ with specific mAb completely abolished the beneficial effect of donor Treg cells. We could further show that only wild-type Treg cells, but not Treg cells from IFN-γ-deficient donor mice, prevented GVHD. This indicated that Treg cell-intrinsic IFN-γ production was required for their protective function. In conclusion, our data show that IFN-γ produced by Foxp3+ Treg cells has essential immune-regulatory functions that are required for prevention of experimental GVHD.

Immunomodulatory role of Ocimum gratissimum and ascorbic acid against nicotine-induced murine peritoneal macrophages in vitro

The aim of this present study was to evaluate the immune functions and immune responses in nicotine-induced (10 mM) macrophages and concurrently establish the immunomodulatory role of aqueous extract of Ocimum gratissimum (Ae-Og) and ascorbic acid. In this study, nitrite generations and some phenotype functions by macrophages were studied. Beside that, release of Th1 cytokines (TNF-α, IL-12) and Th2 cytokines (IL-10, TGF-β) was measured by ELISA, and the expression of these cytokines at mRNA level was analyzed by real-time PCR. Ae-Og, at a dose of 10 μg/mL, significantly reduced the nicotine-induced NO generation and iNOSII expression. Similar kinds of response were observed with supplementation of ascorbic acid (0.01 mM). The administration of Ae-Og and ascorbic acid increased the decreased adherence, chemotaxis, phagocytosis, and intracellular killing of bacteria in nicotine-treated macrophages. Ae-Og and ascorbic acid were found to protect the murine peritoneal macrophages through downregulation of Th1 cytokines in nicotine-treated macrophages with concurrent activation of Th2 responses. These findings strongly enhanced our understanding of the molecular mechanism leading to nicotine-induced suppression of immune functions and provide additional rationale for application of anti-inflammatory therapeutic approaches by O. gratissimum and ascorbic acid for different inflammatory disease prevention and treatment during nicotine toxicity.