Dietary intake of soy genistein is associated with lung function in patients with asthma

Healthy eating index (HEI) as the predictor of asthma: Findings from NHANES

BACKGROUND&AIMS

Previous studies have shown that the formation and development of asthma are closely related to diet. A proper diet can control asthma onset although the precise dietary components involved in preventing or delaying the onset of asthma remain unclear. The healthy eating index (HEI-2015) is a dietary score that measures the overall diet quality as well as the quality of several dietary components. We aimed to explore the relationship between HEI and asthma.

METHODS

This is a cross-sectional study that used data from the 2005 to 2018 National Health and Nutritional Examination Survey (NHANES) in adults (n = 26,567). Our inclusion criteria were adults ≥18 years, completion of asthma-related questionnaires and availability of HEI data. Weighted logistic regression was performed to assess the association between asthma and HEI after adjusting for several covariates.

RESULTS

Patients with asthma were more likely to be female, come from a poorer background, have a raised body mass index (BMI) and a lower HEI total score. Higher HEI total scores were associated with a lower risk of asthma in adults. In addition, eating more whole fruits, more greens and beans, more total protein foods, more seafood and plant proteins, and having a reduced dietary intake of added sugars reduces the risk of asthma. In asthmatic populations, higher HEI scores are associated with older age at onset of asthma.

CONCLUSION

There is an inverse association between the HEI and asthma. This underlines the importance of improving adherence to healthy dietary patterns in the prevention of asthma.

Health-related quality of life in adult patients with asthma according to asthma control and severity: A systematic review and meta-analysis

Background: The utility values are increasingly being used in economic evaluations and health policy decision making. This study aims to conduct a systematic literature review and meta-analysis of the utility values for asthma, particularly with respect to severity and asthma control. Materials and methods: A literature search was conducted using the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases for studies published until July, 2020, reporting the utilities of adult asthma. We extracted utility values derived by nine indirect and four direct utility instruments. Meta-analyses were performed for each utility instrument according to health states based on the level of asthma control and severity. Results: Fifty-two eligible studies were included in our systematic review, of which forty studies were used in the meta-analyses. Among the 13 utility instruments, the most used was EQ-5D-3L, whereas EQ-5D-5L showed the narrowest 95% confidence interval (95% CI, 0.83-0.86) of pooled utility. The pooled utility of asthma declined with worsening control levels and severity. The pooled utility value of EQ-5D-3L was 0.72 (95% CI, 0.63-0.80) for uncontrolled, 0.82 (95% CI, 0.75-0.88) for partly controlled, and 0.87 (95% CI, 0.84-0.90) for well-controlled asthma. Conclusion: Our study shows that EQ-5D-3L and EQ-5D-5L are appropriate for economic evaluations in terms of availability and variability of information, respectively. Asthma patients had poorer utility values with worsened severity and level of asthma control. This study will be useful for health economists conducting economic evaluations of asthma treatments.

Association of the gut microbiome and metabolome with wheeze frequency in childhood asthma

BACKGROUND

While the microbiome has an established role in asthma development, less is known about its contribution to morbidity in children with asthma.

OBJECTIVE

In this ancillary study of the Vitamin D Antenatal Asthma Reduction Trial (VDAART), we analyzed the gut microbiome and metabolome of wheeze frequency in children with asthma.

METHODS

Bacterial 16S ribosomal RNA microbiome and untargeted metabolomic profiling were performed on fecal samples collected from 3-year-old children with parent-reported physician-diagnosed asthma. We analyzed wheeze frequency by calculating the proportion of quarterly questionnaires administered between ages 3 and 5 years in which parents reported the child had wheezed (wheeze proportion). Taxa and metabolites associated with wheeze were analyzed by identifying log fold changes with respect to wheeze frequency and correlation/linear regression analyses, respectively. Microbe-metabolite and microbe-microbe correlation networks were compared between subjects with high and low wheeze proportion.

RESULTS

Specific taxa, including the genus Veillonella and histidine pathway metabolites, were enriched in subjects with high wheeze proportion. Among wheeze-associated taxa, Veillonella and Oscillospiraceae UCG-005, which was inversely associated with wheeze, were correlated with the greatest number of fecal metabolites. Microbial networks were similar between subjects with low versus high wheeze frequency.

CONCLUSION

Gut microbiome features are associated with wheeze frequency in children with asthma, suggesting an impact of the gut microbiome on morbidity in childhood asthma.

Fermented Food in Asthma and Respiratory Allergies—Chance or Failure?

In the last few decades, a dramatic increase in the global prevalence of allergic diseases and asthma was observed. It was hypothesized that diet may be an important immunomodulatory factor influencing susceptibility to allergic diseases. Fermented food, a natural source of living microorganisms and bioactive compounds, has been demonstrated to possess health-promoting potentials and seems to be a promising strategy to reduce the risk of various immune-related diseases, such as allergic diseases and asthma. The exact mechanisms by which allergic diseases and asthma can be alleviated or prevented by fermented food are not well understood; however, its potential to exert an effect through modulating the immune response and influencing the gut microbiota has been recently studied. In this review, we provide the current knowledge on the role of diet, including fermented foods, in preventing or treating allergic diseases and asthma.

The Fermented Soy Product ImmuBalanceTM Suppresses Airway Inflammation in a Murine Model of Asthma

The fermented soy product ImmuBalance contains many active ingredients and its beneficial effects on some allergic diseases have been reported. We hypothesized that ImmuBalance could have potential effects on airway inflammation in a murine model of asthma. Mice sensitized and challenged with ovalbumin developed airway inflammation. Bronchoalveolar lavage fluid was assessed for inflammatory cell counts and levels of cytokines. Lung tissues were examined for cell infiltration and mucus hypersecretion. Oral administration of ImmuBalance significantly inhibited ovalbumin-induced eosinophilic inflammation and decreased Th2 cytokine levels in bronchoalveolar lavage fluid (p < 0.05). In addition, lung histological analysis showed that ImmuBalance inhibited inflammatory cell infiltration and airway mucus production. Our findings suggest that supplementation with ImmuBalance may provide a novel strategy for the prevention or treatment of allergic airway inflammation.

Tempeh: A semicentennial review on its health benefits, fermentation, safety, processing, sustainability, and affordability

Tempeh is a fermented food made of mainly soybeans and is a nutritious, affordable, and sustainable functional source of protein. Globally, tempeh is a widely accepted fermented product. Although there is a growing body of literature on tempeh, most research has focused on unfermented soybeans, thus the impact of tempeh fermentation on biological properties of soybeans has been largely left scattered. The objective of this review is to summarize the literature of tempeh fermentation over the past 60 years. A search of articles on tempeh published from 1960 to 2020 was performed using the Cochrane Library, Web of Science, EBSCOhost FSTA database, and Google Scholar. References from identified articles were reviewed for additional sources. In total, 321 papers were selected for this review, of which 64 papers were related to the health benefits of tempeh. This review concluded that sufficient evidence exists in the literature supporting tempeh fermentation as a low-cost, health-promoting, and sustainable food processing technology to produce protein-rich foods using various beans, legumes, and grains. This comprehensive review suggests further studies are needed on tempeh fermentation and its impact on human health; research and standardization of nonsoy tempeh; assessment of food safety-improving modification in tempeh production system; and initiatives supporting the sourcing of local ingredients in tempeh production.

Flavonoids as natural phenolic compounds and their role in therapeutics: an overview

BACKGROUND

Natural plants and plant-derived formulations have been used by mankind from the ancient period of time. For the past few years, many investigations elaborated the therapeutic potential of various secondary chemicals present in the plants. Literature revealed that the various secondary metabolites, viz. phenolics and flavonoids, are responsible for a variety of therapeutic action in humans.

MAIN BODY

In the present review, an attempt has been made to compile the exploration of natural phenolic compounds with major emphasis on flavonoids and their therapeutic potential too. Interestingly, long-term intake of many dietary foods (rich in phenolics) proved to be protective against the development and management of diabetes, cancer, osteoporosis, cardiovascular diseases and neurodegenerative diseases, etc.

CONCLUSION

This review presents an overview of flavonoid compounds to use them as a potential therapeutic alternative in various diseases and disorders. In addition, the present understanding of phenolics and flavonoids will serve as the basis for the next scientific studies.

In utero exposure to genistein decreased intranasal house dust mite-induced respiratory allergy in middle-aged male B6C3F1 offspring

Despite many hypothesized benefits of dietary isoflavone genistein (GEN) deriving from soy-based products, questions surrounding GEN's developmental effects are increasing. To understand if in utero GEN exposure modulated postnatal respiratory allergies in the middle age, we conducted a time course study in the B6C3F1 offspring (PND 240-330) using a common household allergen (house dust mites: HDM; 10 μg/mouse for PND 240 and 290, and 50 μg/mouse for PND 330, a middle age in mice) following intranasal instillation, a physiological route of allergen exposure. GEN was administered to dams by gavage from gestational day 14 to parturition at a physiologically relevant dose (20 mg/kg body weight). Female and male offspring were sensitized with HDM allergens beginning about one month prior to sacrifice followed by challenges with three weekly dosings of HDM extracts, and they were euthanized at day 3 following the final HDM exposure. In utero exposure to GEN decreased HDM allergen-induced respiratory allergy in male B6C3F1 offspring at PND 330 as reflected by decreases in airway hyperresponsiveness (e.g., Penh value), HDM-specific IgG₁ (a Th2 type Ab) and the activity of eosinophil peroxidase in the lung (an indication of eosinophil recruitment to the lungs). However, in utero exposure to GEN had minimal effects on HDM allergen-induced respiratory allergy in the middle-aged female offspring. Changes in serum total IgE, HDM-specific IgE, and lung histopathology scores in both male and female offspring were not biologically significant. Overall, in utero GEN exposure exerted a protective effect on respiratory allergy in the middle-aged male, but not female, B6C3F1 offspring following later-life HDM exposures.

Protective effects of 17-β-oestradiol and phytoestrogen on age-induced oxidative stress and inhibition of surfactant synthesis in rat type II pneumocytes

Epidemiological data suggest protective effects of oestrogen and phytoestrogen on lung tissue. This study aimed to elucidate the role of 17-β-oestradiol and phytoestrogen in age-related inhibition of surfactant synthesis and oxidative stress in rat type II pneumocytes. Forty male and 66 female Wistar rats were used. Female rats were randomly kept intact or ovariectomized at age 12 months. At age 22 months, ovariectomized rats received 17-β-oestradiol, soy extract, or no treatment. Oxidative stress markers CO, NO, cGMP and lipid peroxide (LPO), antioxidant enzymes and phosphatidylcholine (PC) were measured in cultured type II pneumocytes isolated at ages 2, 14, 18, 22 and 24 months. Old, male and ovariectomized rats showed significantly higher CO, NO, cGMP and LPO and lower PC content and antioxidant enzymes. 17-β-oestradiol and phytoestrogen significantly reversed these effects. In conclusion, aging and oestrogen deprivation decreased PC synthesis and altered the redox status in type II pneumocytes, which were partially restored by 17-β-oestradiol or soy supplementation.

Anti-inflammatory effects of flavonoids

Inflammation plays a key role in diseases such as diabetes, asthma, cardiovascular diseases and cancer. Diet can influence different stages of inflammation and can have an important impact on several inflammatory diseases. Increasing scientific evidence has shown that polyphenolic compounds, such as flavonoids, which are found in fruits, vegetables, legumes, or cocoa, can have anti-inflammatory properties. Recent studies have demonstrated that flavonoids can inhibit regulatory enzymes or transcription factors important for controlling mediators involved in inflammation. Flavonoids are also known as potent antioxidants with the potential to attenuate tissue damage or fibrosis. Consequently, numerous studies in vitro and in animal models have found that flavonoids have the potential to inhibit the onset and development of inflammatory diseases. In the present review, we focused in flavonoids, the most abundant polyphenols in the diet, to give an overview of the most recent scientific knowledge about their impact on different inflammatory diseases.

Soy isoflavones reduce asthma exacerbation in asthmatic patients with high PAI-1-producing genotypes

BACKGROUND

The 4G4G genotype of plasminogen activator inhibitor 1 (PAI-1) is associated with increased plasma PAI-1 levels and poor asthma control. Previous studies suggest that soy isoflavones can reduce PAI-1 levels.

OBJECTIVE

We sought to investigate PAI-1 genotype-specific differences of the soy isoflavone response in asthma outcomes.

METHODS

A PAI-1 functional polymorphism (rs1799768, 4G5G) was characterized in subjects with poorly controlled asthma enrolled in a randomized clinical trial of soy isoflavones (n = 265). Genotype-specific treatment responses on asthma outcomes were compared between soy isoflavones and placebo. Normal human bronchial epithelial cells were cultured with or without TGF-β1, genistein, or both, and PAI-1 levels were measured.

RESULTS

The 4G4G/4G5G genotype was associated with a greater risk for allergy-related worsened asthma symptoms and eczema at baseline compared with the 5G5G genotype. There was a significant interaction between the genotype and soy isoflavone intervention on oral corticosteroid use for asthma exacerbation (P = .005). In a subgroup analysis soy isoflavones significantly reduced the use of oral corticosteroids (number of events/person-year) by 4-fold compared with placebo in the 4G4G/4G5G genotype (0.2 vs 0.8; relative risk, 0.28; P < .001) but not in the 5G5G genotype. Soy isoflavones reduced plasma PAI-1 levels compared with placebo. Genistein treatment reduced TGF-β1-induced PAI-1 production in normal human bronchial epithelial cells.

CONCLUSIONS

This study demonstrates that soy isoflavone treatment provides a significant benefit in reducing the number of severe asthma exacerbations in asthmatic patients with the high PAI-1-producing genotype. PAI-1 polymorphisms can be used as a genetic biomarker for soy isoflavone-responsive patients with asthma.

Bioactivities of Phenolics by Focusing on Suppression of Chronic Diseases: A Review

Phenolics, which are secondary metabolites of plants, exhibit remarkable bioactivities. In this contribution, we have focused on their protective effect against chronic diseases rather than their antioxidant activities, which have been widely discussed in the literature. A large body of epidemiological studies has proven the bioactivities of phenolics in both standard compounds and natural extracts: namely, anticancer, anti-inflammatory, and antibacterial activities as well as reducing diabetes, cardiovascular disease, and neurodegenerative disease. Phenolics also display anti-analgesic, anti-allergic, and anti-Alzheimer’s properties. Thus, this review provides crucial information for better understanding the bioactivities of phenolics in foods and fills a gap in the existing collective and overall knowledge in the field.

Diet and Asthma: Is It Time to Adapt Our Message?

Asthma is a chronic respiratory disorder which is associated with airway inflammation. Environmental factors, in association with genetic susceptibility, play a critical role in asthma pathophysiology. Inhaled allergens, smoke exposure, indoor and outdoor air pollution are common triggers of asthma symptoms. Although the role of diet has clearly established mechanisms in diseases such as cardiovascular disease, type 2 diabetes, and cancer, it is not commonly identified as a causal factor in asthma. However, some dietary patterns, such as the Western diet, which includes a high intake of refined grains, processed and red meats, and desserts, have pro-inflammatory effects. On the contrary, the Mediterranean diet, with high intake of fruits and vegetables has anti-inflammatory properties. The influence of food on asthma outcomes is of growing interest, but dietary habits of asthma patients are not commonly investigated in clinical practice. In this review, we focus on the impact of diet on asthma risk and asthma control. We also detail the influence of diet on obese patients with asthma.

Effect of a soy isoflavone supplement on lung function and clinical outcomes in patients with poorly controlled asthma: a randomized clinical trial

IMPORTANCE

Soy isoflavone supplements are used to treat several chronic diseases, although the data supporting their use are limited. Some data suggest that supplementation with soy isoflavone may be an effective treatment for patients with poor asthma control.

OBJECTIVE

To determine whether a soy isoflavone supplement improves asthma control in adolescent and adult patients with poorly controlled disease.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, randomized, double-blind, placebo-controlled trial conducted between May 2010 and August 2012 at 19 adult and pediatric pulmonary and allergy centers in the American Lung Association Asthma Clinical Research Centers network. Three hundred eighty-six adults and children aged 12 years or older with symptomatic asthma while taking a controller medicine and low dietary soy intake were randomized, and 345 (89%) completed spirometry at week 24.

INTERVENTIONS

Participants were randomly assigned to receive soy isoflavone supplement containing 100 mg of total isoflavones (n=193) or matching placebo (n=193) in 2 divided doses administered daily for 24 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was change in forced expiratory volume in the first second (FEV1) at 24 weeks. Secondary outcome measures were symptoms, episodes of poor asthma control, Asthma Control Test score (range, 5-25; higher scores indicate better control), and systemic and airway biomarkers of inflammation.

RESULTS

Mean changes in prebronchodilator FEV1 over 24 weeks were 0.03 L (95% CI, -0.01 to 0.08 L) in the placebo group and 0.01 L (95% CI, -0.07 to 0.07 L) in the soy isoflavone group, which were not significantly different (P = .36). Mean changes in symptom scores on the Asthma Control Test (placebo, 1.98 [95% CI, 1.42-2.54] vs soy isoflavones, 2.20 [95% CI, 1.53-2.87]; positive values indicate a reduction in symptoms), number of episodes of poor asthma control (placebo, 3.3 [95% CI, 2.7-4.1] vs soy isoflavones, 3.0 [95% CI, 2.4-3.7]), and changes in exhaled nitric oxide (placebo, -3.48 ppb [95% CI, -5.99 to -0.97 ppb] vs soy isoflavones, 1.39 ppb [95% CI, -1.73 to 4.51 ppb]) did not significantly improve more with the soy isoflavone supplement than with placebo. Mean plasma genistein level increased from 4.87 ng/mL to 37.67 ng/mL (P < .001) in participants receiving the supplement.

CONCLUSIONS AND RELEVANCE

Among adults and children aged 12 years or older with poorly controlled asthma while taking a controller medication, use of a soy isoflavone supplement, compared with placebo, did not result in improved lung function or clinical outcomes. These findings suggest that this supplement should not be used for patients with poorly controlled asthma.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01052116.

Resources and biological activities of natural polyphenols

The oxidative stress imposed by reactive oxygen species (ROS) plays an important role in many chronic and degenerative diseases. As an important category of phytochemicals, phenolic compounds universally exist in plants, and have been considered to have high antioxidant ability and free radical scavenging capacity, with the mechanism of inhibiting the enzymes responsible for ROS production and reducing highly oxidized ROS. Therefore, phenolic compounds have attracted increasing attention as potential agents for preventing and treating many oxidative stress-related diseases, such as cardiovascular diseases, cancer, ageing, diabetes mellitus and neurodegenerative diseases. This review summarizes current knowledge of natural polyphenols, including resource, bioactivities, bioavailability and potential toxicity.

A legume product fermented by Saccharomyces cerevisiae modulates cutaneous atopic dermatitis-like inflammation in mice

Background

Isoflavone-containing soy products modulate allergic inflammation in mice. In our previously study, IFN-γ and IL-10 production increased in mice fed with Saccharomyces cerevisiae legume fermented product (SCLFP), demonstrating that SCLFP had immunomodulatory activity. In this study, we tested the anti-inflammatory effects of SCLFP in a mouse model of cutaneous atopic dermatitis inflammation induced by epicutaneous sensitization.

Methods

Epicutaneous exposure to protein allergens plus Staphylococcal enterotoxin B induced a T helper (Th)-2–dominant immune response as well as cutaneous atopic dermatitis-like inflammation in BALB/c mice. The thickness of the skin epithelium, eosinophil migration, and T helper responses were determined in patched skin and draining lymph nodes of mice fed with and without SCLFP.

Results

Epicutaneous exposure to protein allergens plus Staphylococcal enterotoxin B induced a T helper (Th)-2–dominant immune response as well as cutaneous atopic dermatitis-like inflammation in BALB/c mice. SCLFP feeding attenuated this cutaneous Th2 response, as evidenced by decreased thickening of the epidermis, less eosinophil infiltration, and lower levels of IL-5, IL-13, and CXCL11 expression compared to controls. Oral administration of SCLFP also modulated Th1 responses in draining lymph nodes, with lower levels of IFN-γ, IL-4, and IL-17 expression.

Conclusion

Oral intake of SCLFP modulated the induced Th2 inflammatory responses in skin and might have potential applications for the prevention and treatment of atopic dermatitis.

Vitamins C and E for asthma and exercise-induced bronchoconstriction

BACKGROUND

The association between dietary antioxidants and asthma or exercise-induced bronchoconstriction (EIB) is not fully understood. Vitamin C and vitamin E are natural antioxidants that are predominantly present in fruits and vegetables; inadequate vitamin E intake is associated with airway inflammation. It has been postulated that the combination may be more beneficial than either single antioxidant for people with asthma and exercise-induced bronchoconstriction.

OBJECTIVES

To assess the effects of supplementation of vitamins C and E versus placebo (or no vitamin C and E supplementation) on exacerbations and health-related quality of life (HRQL) in adults and children with chronic asthma. To also examine the potential effects of vitamins C and E on exercise-induced bronchoconstriction in people with asthma and in people without a diagnosis of asthma who experience symptoms only on exercise.

SEARCH METHODS

Trials were identified from the Cochrane Airways Review Group Specialised Register and from trial registry websites. Searches were conducted in September 2013.

SELECTION CRITERIA

We included randomised controlled trials of adults and children with a diagnosis of asthma. We separately considered trials in which participants had received a diagnosis of exercise-induced bronchoconstriction (or exercise-induced asthma). Trials comparing vitamin C and E supplementation versus placebo were included. We included trials in which asthma management for treatment and control groups included similar background therapy. Short-term use of vitamins C and E at the time of exacerbation or for cold symptoms in people with asthma is outside the scope of this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of potential studies and subsequently screened full-text study reports for inclusion. We used standard methods as expected by The Cochrane Collaboration.

MAIN RESULTS

It was not possible to aggregate the five included studies (214 participants). Four studies (206 participants) addressed the question of whether differences in outcomes were seen when vitamin C and E supplementation versus placebo was provided for participants with asthma, and only one of those studies (160 children) included a paediatric population; the remaining three studies included a combined total of just 46 adults. An additional study considered the question of whether differences in outcomes were noted when vitamin C and E supplementation was compared with placebo for exercise-induced asthma; this trial included only eight participants. The randomisation process of the trials were unclear leading us to downgrade the quality of the evidence. Four of the studies were double blind while the other study was single blind.None of these studies provided data on our two prespecified primary outcome measures: exacerbations and HRQL. Lung function data obtained from the studies were inconclusive. The only studies that provided any suggestion of an effect, and only with some outcomes, were the paediatric study, especially for children with moderate to severe asthma, and the small study on exercise-induced asthma. Even so, this evidence was judged to be at moderate/low quality. Only one study contributed data on asthma symptoms and adverse events, reporting no evidence of an effect of the intervention for symptoms and that one participant in the treatment group dropped out due to cystitis.

AUTHORS' CONCLUSIONS

It is not possible to draw firm conclusions from this review with respect to the comparison of vitamin C and E supplementation versus placebo in the management of asthma or exercise-induced bronchoconstriction. We found only one study relevant to exercise-induced bronchoconstriction; most included participants came from studies designed to assess the effect of vitamin supplementation on the impact of atmospheric pollutants (such as ozone). Evidence is lacking on the comparison of vitamin C and E supplementation versus placebo for asthma with respect to outcomes such as HRQL and exacerbations, which were not addressed by any of the included studies.When compared with lung function tests alone, HRQL scores and exacerbation frequency are better indicators of the severity of asthma, its impact on daily activities and its response to treatment in a patient population. These end points are well recognised in good quality studies of asthma management. However, clinical studies of vitamins C and E in the management of asthma using these important end points of exacerbations and effects on quality of life are not available, and evidence is insufficient to support robust conclusions on the role of vitamin C and E supplementation in asthma and exercise-induced breathlessness.

Structure-activity association of flavonoids in lung diseases

Flavonoids are polyphenolic compounds classified into flavonols, flavones, flavanones, isoflavones, catechins, anthocyanidins, and chalcones according to their chemical structures. They are abundantly found in Nature and over 8,000 flavonoids have from different sources, mainly plant materials, have been described. Recently reports have shown the valuable effects of flavonoids as antiviral, anti-allergic, antiplatelet, antitumor, antioxidant, and anti-inflammatory agents and interest in these compounds has been increasing since they can be helpful to human health. Several mechanisms of action are involved in the biological properties of flavonoids such as free radical scavenging, transition metal ion chelation, activation of survival genes and signaling pathways, regulation of mitochondrial function and modulation of inflammatory responses. The anti-inflammatory effects of flavonoids have been described in a number of studies in the literature, but not frequently associated to respiratory disease. Thus, this review aims to discuss the effects of different flavonoids in the control of lung inflammation in some disorders such as asthma, lung emphysema and acute respiratory distress syndrome and the possible mechanisms of action, as well as establish some structure-activity relationships between this biological potential and chemical profile of these compounds.

Vitamin C for asthma and exercise-induced bronchoconstriction

BACKGROUND

Dietary antioxidants, such as vitamin C, in the epithelial lining and lining fluids of the lung may be beneficial in the reduction of oxidative damage (Arab 2002). They may therefore be of benefit in reducing symptoms of inflammatory airway conditions such as asthma, and may also be beneficial in reducing exercise-induced bronchoconstriction, which is a well-recognised feature of asthma and is considered a marker of airways inflammation. However, the association between dietary antioxidants and asthma severity or exercise-induced bronchoconstriction is not fully understood.

OBJECTIVES

To examine the effects of vitamin C supplementation on exacerbations and health-related quality of life (HRQL) in adults and children with asthma or exercise-induced bronchoconstriction compared to placebo or no vitamin C.

SEARCH METHODS

We identified trials from the Cochrane Airways Group's Specialised Register (CAGR). The Register contains trial reports identified through systematic searches of a number of bibliographic databases, and handsearching of journals and meeting abstracts. We also searched trial registry websites. The searches were conducted in December 2012.

SELECTION CRITERIA

We included randomised controlled trials (RCTs). We included both adults and children with a diagnosis of asthma. In separate analyses we considered trials with a diagnosis of exercise-induced bronchoconstriction (or exercise-induced asthma). We included trials comparing vitamin C supplementation with placebo, or vitamin C supplementation with no supplementation. We included trials where the asthma management of both treatment and control groups provided similar background therapy. The primary focus of the review is on daily vitamin C supplementation to prevent exacerbations and improve HRQL. The short-term use of vitamin C at the time of exacerbations or for cold symptoms in people with asthma are outside the scope of this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts of potential studies, and subsequently screened full text study reports for inclusion. We used standard methods expected by The Cochrane Collaboration.

MAIN RESULTS

A total of 11 trials with 419 participants met our inclusion criteria. In 10 studies the participants were adults and only one was in children. Reporting of study design was inadequate to determine risk of bias for most of the studies and poor availability of data for our key outcomes may indicate some selective outcome reporting. Four studies were parallel-group and the remainder were cross-over studies. Eight studies included people with asthma and three studies included 40 participants with exercise-induced asthma. Five studies reported results using single-dose regimes prior to bronchial challenges or exercise tests. There was marked heterogeneity in vitamin C dosage regimes used in the selected studies, compounding the difficulties in carrying out meaningful analyses.One study on 201 adults with asthma reported no significant difference in our primary outcome, health-related quality of life (HRQL), and overall the quality of this evidence was low. There were no data available to evaluate the effects of vitamin C supplementation on our other primary outcome, exacerbations in adults. One small study reported data on asthma exacerbations in children and there were no exacerbations in either the vitamin C or placebo groups (very low quality evidence). In another study conducted in 41 adults, exacerbations were not defined according to our criteria and the data were not available in a format suitable for evaluation by our methods. Lung function and symptoms data were contributed by single studies. We rated the quality of this evidence as moderate, but further research is required to assess any clinical implications that may be related to the changes in these parameters. In each of these outcomes there was no significant difference between vitamin C and placebo. No adverse events at all were reported; again this is very low quality evidence.Studies in exercise-induced bronchoconstriction suggested some improvement in lung function measures with vitamin C supplementation, but theses studies were few and very small, with limited data and we judged the quality of the evidence to be low.

AUTHORS' CONCLUSIONS

Currently, evidence is not available to provide a robust assessment on the use of vitamin C in the management of asthma or exercise-induced bronchoconstriction. Further research is very likely to have an important impact on our confidence in the estimates of effect and is likely to change the estimates. There is no indication currently that vitamin C can be recommended as a therapeutic agent in asthma. There was some indication that vitamin C was helpful in exercise-induced breathlessness in terms of lung function and symptoms; however, as these findings were provided only by small studies they are inconclusive. Most published studies to date are too small and inconsistent to provide guidance. Well-designed trials with good quality clinical endpoints, such as exacerbation rates and health-related quality of life scores, are required.

Oxidative stress and antioxidant deficiencies in asthma: potential modification by diet

The lungs of asthmatic patients are exposed to oxidative stress due to the generation of reactive oxygen and nitrogen species as a consequence of chronic airway inflammation. Increased concentrations of NO*, H2O2 and 8-isoprostane have been measured in exhaled breath and induced sputum of asthmatic patients. O2*-, NO*, and halides interact to form highly reactive species such as peroxynitrite and HOBr, which in turn cause nitration and bromination of protein tyrosine residues. Oxidative stress may also reduce glutathione levels and cause inactivation of antioxidant enzymes such as superoxide dismutase, with a consequent increase in apoptosis, shedding of airway epithelial cells and airway remodelling. The oxidant/antioxidant equilibrium in asthmatic patients may be further perturbed by low dietary intakes of the antioxidant vitamins C and E, selenium and flavonoids, with a consequent lowering of the concentrations of these and other non-dietary antioxidants such as bilirubin and albumin in plasma and airway epithelial lining fluid. Although supplementation with vitamins C and E appears to offer protection against the adverse effects of ozone, recent randomised, placebo-controlled trials of vitamin C or E supplements for patients with mild asthma have not shown significant benefits over standard therapy. However, genetic variation in glutathione S-transferase may influence the susceptibility of asthmatic individuals to oxidative stress and the extent to which they are likely to benefit from antioxidant supplementation. Long-term prospective trials are required to determine whether modification of dietary intake will benefit asthma patients and reduce the socio-economic burden of asthma in the community.

Association of dietary soy genistein intake with lung function and asthma control: a post-hoc analysis of patients enrolled in a prospective multicentre clinical trial

BACKGROUND

Broad dietary patterns have been linked to asthma but the relative contribution of specific nutrients is unclear. Soy genistein has important anti-inflammatory and other biological effects that might be beneficial in asthma. A positive association was previously reported between soy genistein intake and lung function but not with asthma exacerbations.

AIMS

To conduct a post-hoc analysis of patients with inadequately controlled asthma enrolled in a prospective multicentre clinical trial to replicate this association.

METHODS

A total of 300 study participants were included in the analysis. Dietary soy genistein intake was measured using the Block Soy Foods Screener. The level of soy genistein intake (little or no intake, moderate intake, or high intake) was compared with baseline lung function (pre-bronchodilator forced expiratory volume in 1 second (FEV(1))) and asthma control (proportion of participants with an episode of poor asthma control (EPAC) and annualised rates of EPACs over a 6-month follow-up period.

RESULTS

Participants with little or no genistein intake had a lower baseline FEV(1) than those with a moderate or high intake (2.26 L vs. 2.53 L and 2.47 L, respectively; p=0.01). EPACs were more common among those with no genistein intake than in those with a moderate or high intake (54% vs. 35% vs. 40%, respectively; p<0.001). These findings remained significant after adjustment for patient demographics and body mass index.

CONCLUSIONS

In patients with asthma, consumption of a diet with moderate to high amounts of soy genistein is associated with better lung function and better asthma control.

Regulation of the immune response by soybean isoflavones

Soybeans are rich in immuno-modulatory isoflavones such as genistein, daidzein, and glycitein. These isoflavones are well-known antioxidants, chemopreventive and anti-inflammatory agents. Several epidemiological studies suggest that consumption of traditional soy food containing isoflavones is associated with reduced prevalence of chronic health disorders. Isoflavones are considered to be phytoestrogens because of their ability to bind to estrogen receptors. The literature is extensive on the chemistry, bio-availability, and bio-activity of isoflavones. However, their effects on immune response are yet to be fully understood, but are beginning to be appreciated. We review the role of isoflavones in regulation of the immune response and their potential clinical applications in immune-dysfunction. Special emphasis will be made regarding in vivo studies including humans and animal model systems.

Isoflavones, genistein and daidzein, regulate mucosal immune response by suppressing dendritic cell function

Lipopolysaccharide (LPS), a component of gram-negative bacterial cell walls, has been shown to have a strong adjuvant effect towards inhaled antigens contributing to airway inflammation. Isoflavones are anti-inflammatory molecules present in abundant quantities in soybeans. We investigated the effect of isoflavones on human dendritic cell (DC) activation via LPS stimulation and subsequent DC-mediated effector cell function both in vitro and in a mouse model of upper airway inflammation. Human monocyte-derived DCs (MDDC) were matured with LPS (or TNF-α) +/− isoflavones (genistein or daidzein). The surface expression levels of DC activation markers were analyzed by flow cytometry. Mature DCs +/− isoflavones were washed and cultured with freshly-isolated allogenic naïve CD4⁺ T cells for 5 days or with autologous natural killer (NK) cells for 2 hours. The percentages of proliferating IFN-γ⁺ CD4⁺ T cells and cytokine levels in culture supernatants were assessed. NK cell degranulation and DC cytotoxicity were measured by flow cytometry. Isoflavones significantly suppressed the activation-induced expression of DC maturation markers (CD83, CD80, CD86) and MHC class I but not MHC class II molecules in vitro. Isoflavone treatment inhibited the ability of LPS-DCs to induce IFN-γ in CD4⁺ T cells. NK cell degranulation and the percentage of dead DCs were significantly increased in isoflavone-treated DC-NK co-culture experiments. Dietary isoflavones suppressed the mucosal immune response to intra-nasal sensitization of mice to ovalbumin. Similar results were obtained when isoflavones were co-administered during sensitization. These results demonstrate that soybean isoflavones suppress immune sensitization by suppressing DC-maturation and its subsequent DC-mediated effector cell functions.

Asthma outcomes: symptoms

BACKGROUND

Respiratory symptoms are commonly used to assess the impact of patient-centered interventions.

OBJECTIVE

At the request of National Institutes of Health (NIH) institutes and other federal agencies, an expert group was convened to propose which measurements of asthma symptoms should be used as a standardized measure in future clinical research studies.

METHODS

Asthma symptom instruments were classified as daily diaries (prospectively recording symptoms between research visits) or retrospective questionnaires (completed at research visits). We conducted a systematic search in PubMed and a search for articles that cited key studies describing development of instruments. We classified outcome instruments as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an NIH-organized workshop in March 2010 and finalized in September 2011.

RESULTS

Four instruments (3 daily diaries, 1 for adults and 2 for children; and 1 retrospective questionnaire for adults) were identified. Minimal clinically important differences have not been established for these instruments, and validation studies were only conducted in a limited number of patient populations. Validity of existing instruments may not be generalizable across racial-ethnic or other subgroups.

CONCLUSIONS

An evaluation of symptoms should be a core asthma outcome measure in clinical research. However, available instruments have limitations that preclude selection of a core instrument. The working group participants propose validation studies in diverse populations, comparisons of diaries versus retrospective questionnaires, and evaluations of symptom assessment alone versus composite scores of asthma control.

Genistein attenuated allergic airway inflammation by modulating the transcription factors T-bet, GATA-3 and STAT-6 in a murine model of asthma

BACKGROUND

Genistein, a flavonoid in legumes and some herbal medicines, has various biological actions. Previous studies have shown that genistein decreased airway inflammation in allergic asthma. However, studies on how genistein affects immunoreactions in asthma are very limited.

OBJECTIVE

It was the aim of this study to investigate the effect of genistein on T helper 1 (Th1)/Th2 cytokines in a murine asthma model and to explore its underlying mechanisms.

METHODS

The asthma model was set up both in vivo and in vitro: the mice were divided into four groups in vivo, i.e. control group, ovalbumin-sensitized (OVA) group, Gen20 group (20 mg/kg genistein) and Gen40 group (40 mg/kg genistein), and into three groups in vitro, i.e. control group, OVA group, genistein group. Changes in lung histology were observed and concentrations of interleukin-4, interleukin-5 and interferon-γ in bronchoalveolar lavage fluid and serum were measured by enzyme-linked immunosorbent assay. The mRNA expression of GATA binding protein 3 (GATA-3), signal transducer and activator of transcription 6 (STAT-6) and T-box transcription factor (T-bet) in the lungs and CD4+ T cells of each group were detected by real-time PCR and the corresponding proteins were detected by Western blot.

RESULTS

The results showed that genistein attenuated OVA-induced airway inflammation, decreased Th2-type cytokines and increased Th1-type cytokines. Additionally, our data suggested that genistein may modulate the Th1/Th2 reaction by inhibiting GATA-3 and STAT-6 production while increasing T-bet production.

CONCLUSION

Genistein may modulate the immunomodulatory actions caused by Th1/Th2 cytokines in asthma, at least partially, by the down-regulation of GATA-3 and STAT-6 and the up-regulation of T-bet.

Alternative and complementary treatment for food allergy

Despite increased consumer interest in complementary and alternative medicine (CAM) for the treatment of food allergy, there remains a relative paucity of knowledge regarding the clinical efficacy, mechanisms of action, and safety of most CAM treatments available to consumers. This article focuses on recent advances in CAM for food allergy, including acupuncture, herbal medicine, probiotics, and alternative approaches to allergen immunotherapy. The mechanism of action of several novel approaches to treatment of food allergy is reviewed, but FAHF-2 is the only investigational herbal formulation currently validated for use in human clinical trials.

Soybean isoflavones regulate dendritic cell function and suppress allergic sensitization to peanut

BACKGROUND

Although peanut and soybean proteins share extensive amino acid sequence homology, the incidence and severity of allergic reactions to soy are much less than those to peanut. Soybeans are rich in anti-inflammatory isoflavones and are the most common source of isoflavones in the human food supply.

OBJECTIVE

We hypothesized that the active isoflavones in the gut milieu are capable of modulating immune responses to dietary antigens by regulating dendritic cell (DC) function.

METHODS

We tested this hypothesis in a murine model of peanut allergy and in human monocyte-derived dendritic cells (MDDCs). C3H/HeJ mice were fed a diet containing genistein and daidzein. The mice were sensitized and challenged with peanut, and the anaphylactic symptoms were compared with those of mice fed a soy-free diet. Human MDDCs were activated with cholera toxin in the presence of isoflavones. The surface expression of DC activation markers and DC-mediated effector functions were analyzed by means of flow cytometry.

RESULTS

Dietary isoflavones significantly reduced the anaphylactic symptoms and mast cell degranulation in vivo after peanut challenge. Serum peanut-specific antibodies were markedly reduced in mice fed the isoflavone diet. Isoflavones inhibited cholera toxin-induced DC maturation in the mesenteric lymph nodes and human MDDCs and subsequent DC-mediated CD4(+) T-cell function in vitro.

CONCLUSIONS

These data suggest that dietary isoflavones suppress allergic sensitization and protect against peanut allergy in vivo. Dietary supplementation of soybean isoflavones could be a novel strategy to prevent the development of allergic reactions to food.

Oxidative stress in asthma

Asthma is a chronic inflammatory lung disease that results in airflow limitation, hyperreactivity, and airway remodeling. There is strong evidence that an imbalance between the reducing and oxidizing systems favoring a more oxidative state is present in asthma. Endogenous and exogenous reactive oxygen species, such as superoxide anion, hydroxyl radical, hypohalite radical, and hydrogen peroxide, and reactive nitrogen species, such as nitric oxide, peroxynitrite, and nitrite, play a major role in the airway inflammation and are determinants of asthma severity. Asthma is also associated with decreased antioxidant defenses, such as superoxide dismutase, catalase, and glutathione. In this review, we will summarize the current knowledge and discuss the current and future strategies for the modulation of oxidative stress in asthma.

Inhibition of airway inflammation, hyperresponsiveness and remodeling by soy isoflavone in a murine model of allergic asthma

Epidemiologic studies have associated higher dietary consumption of soy isoflavones with decreased self-report of cough and allergic respiratory symptoms, but the pharmacodynamic effects of soy isoflavone on asthmatic model have not been well-described. Here, we hypothesized that soy isoflavone may have potential effects on airway hyperresponsiveness, inflammation and airway remodeling in a murine of asthma. Mice sensitized and challenged with ovalbumin developed airway inflammation. Bronchoalveolar lavage fluid was assessed for inflammatory cell counts, and for cytokine levels. Lung tissues were examined for cell infiltration, mucus hypersecretion and airway remodeling, and for the expression of inflammatory biomarkers. Airway hyperresponsiveness was monitored by direct airway resistance analysis. Oral administration of soy isoflavone significantly reduced ovalbumin-induced airway hyperresponsiveness to intravenous methacholine, and inhibited ovalbumin-induced increases in eosinophil counts. RT-PCR analysis of whole lung lysates revealed that soy isoflavone markedly suppressed ovalbumin-induced mRNA expression of eotaxin, interleukin(IL)-5, IL-4 and matrix metalloproteinase-9, and increased mRNA expression of interferon (IFN)-γ and tissue inhibitor of metalloproteinase-1 in a dose-dependent manner. Soy isoflavone also substantially recovered IFN-γ/IL-4 (Th1/Th2) levels in bronchoalveolar lavage fluid. In addition, histologic studies showed that soy isoflavone dramatically inhibited ovalbumin-induced lung tissue eosinophil infiltration, airway mucus production and collagen deposition in lung tissues. Our findings suggest that soy isoflavone as nutritional supplement may provide a novel means for the treatment of airway inflammatory disease.

Epigenetic changes induced by curcumin and other natural compounds

Epigenetic regulation, which includes changes in DNA methylation, histone modifications, and alteration in microRNA (miRNA) expression without any change in the DNA sequence, constitutes an important mechanism by which dietary components can selectively activate or inactivate gene expression. Curcumin (diferuloylmethane), a component of the golden spice Curcuma longa, commonly known as turmeric, has recently been determined to induce epigenetic changes. This review summarizes current knowledge about the effect of curcumin on the regulation of histone deacetylases, histone acetyltransferases, DNA methyltransferase I, and miRNAs. How these changes lead to modulation of gene expression is also discussed. We also discuss other nutraceuticals which exhibit similar properties. The development of curcumin for clinical use as a regulator of epigenetic changes, however, needs further investigation to determine novel and effective chemopreventive strategies, either alone or in combination with other anticancer agents, for improving cancer treatment.

Biochanin a, a phytoestrogenic isoflavone with selective inhibition of phosphodiesterase 4, suppresses ovalbumin-induced airway hyperresponsiveness

The present study investigated the potential of biochanin A, a phytoestrogenic isoflavone of red clover (Triflolium pratense), for use in treating asthma or chronic obstructive pulmonary disease (COPD). Biochanin A (100 μmol/kg, orally (p.o.)) significantly attenuated airway resistance (R_L), enhanced pause (P_enh), and increased lung dynamic compliance (C_dyn) values induced by methacholine (MCh) in sensitized and challenged mice. It also significantly suppressed an increase in the number of total inflammatory cells, neutrophils, and eosinophils, and levels of cytokines, including interleukin (IL)-2, IL-4, IL-5, and tumor necrosis factor (TNF)-α in bronchoalveolar lavage fluid (BALF) of the mice. However, it did not influence interferon (IFN)-γ levels. Biochanin A (100 μmol/kg, p.o.) also significantly suppressed the total and ovalbumin (OVA)-specific immunoglobulin E (IgE) levels in the serum and BALF, and enhanced the total IgG_2a level in the serum of these mice. The PDE4_H/PDE4_L value of biochanin A was calculated as >35. Biochanin A did not influence xylazine/ketamine-induced anesthesia. Biochanin A (10~30 μM) significantly reduced cumulative OVA (10~100 μg/mL)-induced contractions in the isolated guinea pig trachealis, suggesting that it inhibits degranulation of mast cells. In conclusion, red clover containing biochanin A has the potential for treating allergic asthma and COPD.

Plant polyphenols as dietary antioxidants in human health and disease

Polyphenols are secondary metabolites of plants and are generally involved in defense against ultraviolet radiation or aggression by pathogens. In the last decade, there has been much interest in the potential health benefits of dietary plant polyphenols as antioxidant. Epidemiological studies and associated meta-analyses strongly suggest that long term consumption of diets rich in plant polyphenols offer protection against development of cancers, cardiovascular diseases, diabetes, osteoporosis and neurodegenerative diseases. Here we present knowledge about the biological effects of plant polyphenols in the context of relevance to human health.

Genistein, a competitive PDE1-4 inhibitor, may bind on high-affinity rolipram binding sites of brain cell membranes and then induce gastrointestinal adverse effects

The affinities of genistein on phosphodiesterase (PDE)1-4 and cause of gastrointestinal adverse effects of genistein remain unclear. Female BALB/c mice were actively sensitized by intraperitoneal injections of ovalbumin and challenged by aerosolized ovalbumin (1%). After secondary challenge, aerosolized methacholine (6.25-50mg/ml) induced increases of enhanced pause (P(enh)) values in conscious mice in a concentration-dependent manner. Genistein (30-100 micromol/kg, i.p.) markedly inhibited methacholine (12.5-50mg/ml)-induced increase of P(enh) value in the sensitized and challenged mice. In addition, genistein significantly reduced total inflammatory cells, macrophages, lymphocytes, neutrophils, and eosinophils in bronchoalveolar lavage fluid, with the exception that lymphocytes and neutrophils were not significantly inhibited by genistein at the lowest dose (10 micromol/kg). Genistein also markedly attenuated the release of cytokines, including interleukin (IL)-2, IL-4, IL-5, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha. Genistein competitively inhibited PDE1-4, with a K(i) value ranging from 4.3 to 13.7 microM. Genistein (3-300 microM) concentration-dependently displaced 2nM [(3)H]-rolipram bound on high-affinity rolipram binding sites of brain cell membranes. The therapeutic ratio of genistein was calculated to be 7.9. Genistein (100 micromol/kg, s.c.) significantly shortened xylazine/ketamine-induced anesthesia, suggesting that genistein administered at a higher dose may have gastrointestinal adverse effects. In conclusion, owing to the low therapeutic ratio of genistein, the gastrointestinal adverse effects may be induced via the binding of genistein on high-affinity rolipram binding sites of brain cell membranes, when it is used for a long term or at higher doses for treating allergies, asthma or chronic obstructive pulmonary disease.

Diet and asthma

PURPOSE OF REVIEW

The goal of this review is to assess recent additions to the medical literature that contribute to the clinical question: 'How might diet act as a disease modifier in patients with asthma?' In vitro, animal, and epidemiologic data are presented as justification for interventional studies, which form the basis of clinical recommendations and decision-making.

RECENT FINDINGS

A number of studies suggest roles for n-3 fatty acids, soy isoflavones, vitamin D, and antioxidants as modifiers of asthma severity. However, these studies are generally complicated by small sample sizes and either negative results or findings that are of questionable clinical significance.

SUMMARY

The available literature regarding dietary manipulation as asthma therapy is largely unconvincing. Although mechanistic and epidemiologic studies provide a rationale for diet therapies, there are few interventional studies with positive, clinically relevant endpoints. Future studies must include sufficient numbers of well selected patients and measure effects on exacerbations, symptoms, lung function, and medication use.

Isoflavones regulate innate immunity and inhibit experimental colitis

BACKGROUND AND AIM

Dysregulated immune responses in the gut to luminal antigens can cause inflammatory bowel diseases (IBD). The roles played by dietary antigens in the pathogenesis or prevention of IBD are poorly understood. Soybean isoflavones are digested in large amounts and have many biological activities. The aim of this study was to determine whether isoflavones in aglycon and bioavailable forms have any effect on gut immunity and protect the host from tissue damage in a mouse model of colitis.

METHODS

We administered daidzein-rich isoflavone aglycones (DRIA) to mice for 1 week and then treated them with 2% dextran sodium sulfate (DSS) in drinking water for 4 days to induce colitis. The effect of DRIA was evaluated by examining the histopathology of the colon, body weight changes, and functional analysis of mesenteric lymph node cells (MLN).

RESULTS

DRIA inhibited interleukin (IL)-6 and IL-8 production by Toll-like receptor (TLR)2, and TLR4-stimulated monocytes in a dose-dependent manner. The mice administered DRIA had less inflammation and tissue damage in the colon than the control mice. This protective effect of DRIA was associated with a decrease in interferon-gamma, IL-6, and IL-12p40 secretion, and an increase in IL-10 secretion and low cell-activation status of antigen-presenting cells (APC) in MLN.

CONCLUSION

Ingested DRIA can downregulate the functions of APC and inhibit DSS colitis.

NF-kappaB signaling pathway and its therapeutic implications in human diseases

The nuclear factor-kappaB (NF-kappaB) pathway is one of the most important cellular signal transduction pathways involved in both physiologic processes and disease conditions. It plays important roles in the control of immune function, inflammation, stress response, differentiation, apoptosis, and cell survival. Moreover, NF-kappaB is critically involved in the processes of development and progression of cancers. More importantly, recent studies have shown that NF-kappaB signaling also plays critical roles in the epithelial-mesenchymal transition (EMT) and cancer stem cells. Therefore, targeting of NF-kappaB signaling pathway could be a potent strategy for the prevention and/or treatment of human cancers and inflammatory diseases.

(Xeno)estrogen regulation of food allergy

Food allergy and other types of allergies are becoming epidemic in both the developed and developing countries. A large amount of information is available in literature that (xeno)estrogens can regulate the immune response in general, and the development of allergy in particular; however, the effect of (xeno)estrogens on food allergy is basically unknown. With increasing use of xenobiotics worldwide, chemicals with estrogenic activity have been accumulating in our environment. This review has summarized the current literature relating to the topic (xeno)estrogen regulation of food allergy. The effect of (xeno)estrogens on enterocytes, proteases for protein hydrolysis, dendritic cells and T-regulatory cells in the gastrointestinal tract has been discussed. Finally, considering the current confusion in literature regarding the effect of phytoestrogen genistein on the immune system, a brief discussion has been included for its effect on T(H)1-T(H)2 polarization, and possibly food allergy in its relation to windows of exposure. Sufficient evidences exist to support the notion that (xeno)estrogens can regulate food allergy, with the developmental periods more sensitive. Further clinical and animal studies are needed to determine the causal relationship between the exposure of (xeno)estrogens and incidence of food allergy, and the underlying mechanisms.

A mechanism of benefit of soy genistein in asthma: inhibition of eosinophil p38-dependent leukotriene synthesis

BACKGROUND

Dietary intake of the soy isoflavone genistein is associated with reduced severity of asthma, but the mechanisms responsible for this effect are unknown.

OBJECTIVE

To determine whether genistein blocks eosinophil leukotriene C(4) (LTC(4)) synthesis and to evaluate the mechanism of this effect, and to assess the impact of a 4-week period of soy isoflavone dietary supplementation on indices of eosinophilic inflammation in asthma patients.

METHODS

Human peripheral blood eosinophils were stimulated in the absence and presence of genistein, and LTC(4) synthesis was measured. 5-lipoxygenase (5-LO) nuclear membrane translocation was assessed by confocal immunofluorescence microscopy. Mitogen-activated protein (MAP) kinase activation was determined by immunoblot. Human subjects with mild-to-moderate persistent asthma and minimal or no soy intake were given a soy isoflavone supplement (100 mg/day) for 4 weeks. The fraction of exhaled nitric oxide (FE(NO)) and ex vivo eosinophil LTC(4) production were assessed before and after the soy isoflavone treatment period.

RESULTS

Genistein inhibited eosinophil LTC(4) synthesis (IC(50) 80 nm), blocked phosphorylation of p38 MAP kinase and its downstream target MAPKAP-2, and reduced translocation of 5-LO to the nuclear membrane. In patients with asthma, following 4 weeks of dietary soy isoflavone supplementation, ex vivo eosinophil LTC(4) synthesis decreased by 33% (N=11, P=0.02) and FE(NO) decreased by 18% (N=13, P=0.03).

CONCLUSION

At physiologically relevant concentrations, genistein inhibits eosinophil LTC(4) synthesis in vitro, probably by blocking p38- and MAPKAP-2-dependent activation of 5-LO. In asthma patients, dietary soy isoflavone supplementation reduces eosinophil LTC(4) synthesis and eosinophilic airway inflammation. These results support a potential role for soy isoflavones in the treatment of asthma.

The association of diet with respiratory symptoms and asthma in schoolchildren in Taipei, Taiwan

This study aimed to evaluate the association of diet with respiratory symptoms and asthma in schoolchildren in Taipei, Taiwan. An in-class interview survey elicited experiences of asthma and respiratory symptoms and consumption frequencies of the major food categories in 2290 fifth graders. Respiratory symptoms surveyed included persistent cough, chest tightness, wheezing with cold, wheezing without cold, dyspnea-associated wheezing, and exercise-induced cough or wheezing. Results showed that the consumption of sweetened beverages had the strongest association with respiratory symptoms and was positively associated with six of the seven respiratory symptoms (all p < 0.05). The adjusted odds ratios (aOR) ranged from 1.05 (95% confidence interval (CI = 1.01-1.09) for exercise-induced cough to 1.09 (95% CI = 1.03-1.16) for wheezing without cold. Egg consumption was associated with 5 of the 7 respiratory symptoms. Consumptions of seafood, soy products, and fruits were each negatively associated with one of the seven respiratory symptoms (all p < 0.05). Consumption of seafood was negatively associated with physician-diagnosed asthma and consumptions of sweetened beverages and eggs were positively associated with suspected asthma (p < 0.05). In conclusion, the study suggests that diet is associated with the respiratory symptoms in schoolchildren in Taipei. Consumptions of sweetened beverages and eggs are associated with increased risk of respiratory symptoms and asthma whereas consumptions of soy products and fruits are associated with reduced risk of respiratory symptoms.

Endocrine disrupters--potential modulators of the immune system and allergic response

Endocrine disrupters (EDs) are environmental pollutants of industrial or agricultural origin (e.g. herbicides, fungicides, insecticides, industrial chemicals) that may influence health of wildlife and human. Endocrine-disrupting effect is obtained by mimicking the action of the steroid hormones and has been associated with several reproductive disorders as well as cancerogenesis both in animals and humans. EDs can also influence synthesis of cytokines, immunoglobulins, and cell mediators as well as immune cell activation and survival. Modulation by EDs of interleukin-4 production, Th1/Th2 balance and IgE production suggest their potential effect on allergic immune responses. The aim of this review was to summarize data indicating a potential effect of EDs exposure on the immune system and allergic responses.

Upregulation of substance P receptor expression by calcitonin gene-related peptide, a possible cooperative action of two neuropeptides involved in airway inflammation

Airway hyperresponsiveness (AHR) is present in almost all patients with symptomatic asthma, yet its mechanism is not well understood. Airway inflammation is thought to be an important underlying mechanism involved in causing AHR. Recent studies indicate release of neuropeptides from C-fiber endings plays a pivotal role in airway inflammation. Substance P (SP) is a critical neurotransmitter of sensory C-fiber and a well-known effector of inflammatory response. However, roles of other neuropeptides and interaction among these neuropeptides in airway inflammation and AHR were largely unknown. Calcitonin gene-related peptide (CGRP), another intrapulmonary neuropeptide that functions as a potent vasodilator and neutrophils activator, is released from the same C-fiber ending as SP is released. By using an ozone-stressing animal model, previously we had demonstrated that CGRP might be involved in the development of AHR in rabbits. To extend the functional roles of SP, and to explore the possible interactive roles of SP and CGRP in airway inflammation, we examined expressions of SP, SP receptor (neurokinin 1, or NK-1R) and CGRP in vivo and ex vivo. We exposed guinea pigs at intervals to inhalation of ozone to induce airway inflammation. Animals were sacrificed at different time points; SP, SP receptor and CGRP expression were determined during the onset and progression of airway inflammation by radioimmunoassay, immunohistochemistry and in situ hybridization. Our data showed that after exposure to ozone, the concentration of SP in lung homogenate and the number of SP-immunoreactive cell bodies in lung slides increased within 24h, peaked on day 2, and then decreased slowly. Interestingly, CGRP expressions exhibited a similar temporal and spatial pattern, and there was a strong correlation between SP expression and CGRP expression, indicating a possible cooperative action of these two neuropeptides. We also noted an increased expression of SP receptor NK-1R in the development of airway inflammation. In order to test the hypothesis that CGRP as a coexisting neurotransmitter with SP can regulate the expression of NK-1R in the lung, and contribute to the SP-mediated inflammatory response, we used in vitro lung tissue culture to determine the effect of CGRP on NK-1R expression. We found that NK-1R expression was induced by CGRP incubation at both mRNA and protein levels, and the induction was attenuated by additions of the inhibitors of Protein Kinase A (PKA) pathway, Calmodulin-dependent Kinase pathway, and Tyrosine Protein Kinase pathway. In conclusion, our data provide compelling evidence that SP and CGRP are involved in the development of airway inflammation. The interaction between SP and CGRP is likely to contribute to the pathogenesis of AHR and other lung inflammatory diseases.