Antiinflammatory effects of genistein, a tyrosine kinase inhibitor, on a guinea pig model of asthma

Suppression of ovalbumin-induced Th2-driven airway inflammation by β-sitosterol in a guinea pig model of asthma

In the present study, the efficacy of β-sitosterol isolated from an n-butanol extract of the seeds of the plant Moringa oleifera (Moringaceae) was examined against ovalbumin-induced airway inflammation in guinea pigs. All animals (except group I) were sensitized subcutaneously and challenged with aerosolized 0.5% ovalbumin. The test drugs, β-sitosterol (2.5mg/kg) or dexamethasone (2.5mg/kg), were administered to the animals (p.o.) prior to challenge with ovalbumin. During the experimental period (on days 18, 21, 24 and 29), a bronchoconstriction test (0.25% acetylcholine for 30s) was performed and lung function parameters (tidal volume and respiration rate) were measured for each animal. On day 30, blood and bronchoalveolar lavaged fluid were collected to assess cellular content, and serum was collected for cytokine assays. Lung tissue was utilized for a histamine assay and for histopathology. β-sitosterol significantly increased the tidal volume (V(t)) and decreased the respiration rate (f) of sensitized and challenged guinea pigs to the level of non-sensitized control guinea pigs and lowered both the total and differential cell counts, particularly eosinophils and neutrophils, in blood and bronchoalveolar lavaged fluid. Furthermore, β-sitosterol treatment suppressed the increase in cytokine levels (TNFα, IL-4 and IL-5), with the exception of IL-6, in serum and in bronchoalveolar lavaged fluid detected in model control animals. Moreover, treatment with β-sitosterol protected against airway inflammation in lung tissue histopathology. β-sitosterol possesses anti-asthmatic actions that might be mediated by inhibiting the cellular responses and subsequent release/synthesis of Th2 cytokines. This compound may have therapeutic potential in allergic asthma.

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.

Genistein, a general kinase inhibitor, as a potential antiviral for arenaviral hemorrhagic fever as described in the Pirital virus-Syrian golden hamster model

Arenaviruses are rodent-borne negative strand RNA viruses and infection of these viruses in humans may result in disease and hemorrhagic fever. To date, supportive care, ribavirin, and in some cases immune plasma remain the foremost treatment options for arenaviral hemorrhagic fever. Research with the hemorrhagic fever causing-arenaviruses usually requires a Biosafety level (BSL)-4 environment; however, surrogate animal model systems have been developed to preliminarily study and screen various vaccines and antivirals. The Syrian golden hamster-Pirital virus (PIRV) surrogate model of hemorrhagic fever provides an opportunity to test new antivirals in an ABSL-3 setting. Thus, we challenged hamsters, implanted with telemetry, with PIRV and observed viremia and tissue viral titers, and changes in core body temperature, hematology, clinical chemistry, and coagulation parameters. Physical signs of disease of the PIRV-infected hamsters included weight loss, lethargy, petechial rashes, epistaxis, ocular orbital and rectal hemorrhage, and visible signs of neurologic disorders. However, treating animals with genistein, a plant derived isoflavone and general kinase inhibitor, resulted in increased survival rates and led to an improved clinical profile. In all, the results from this study demonstrate the potential of a general kinase inhibitor genistein as an antiviral against arenaviral hemorrhagic fever.

The activity of medicinal plants and secondary metabolites on eosinophilic inflammation

Eosinophils are leukocytes that are present in several body compartments and in the blood at relatively low numbers under normal conditions. However, an increase in the number of eosinophils, in the blood or in the tissues, is observed in allergic or parasitic disorders. Although some progress has been made in understanding the development of eosinophil-mediated inflammation in allergic and parasitic diseases, the discovery of new compounds to control eosinophilia has lagged behind other advances. Plant-derived secondary metabolites are the basis for many drugs currently used to treat pathologic conditions, including eosinophilic diseases. Several studies, including our own, have demonstrated that plant extracts and secondary metabolites can reduce eosinophilia and eosinophil recruitment in different experimental animal models. In this review, we summarize these studies and describe the anti-eosinophilic activity of various plant extracts, such as Ginkgo biloba, Allium cepa, and Lafoensia pacari, as well as those of secondary metabolites (compounds isolated from plant extracts), such as quercetin and ellagic acid. In addition, we highlight the medical potential of these plant-derived compounds for treating eosinophil-mediated inflammation, such as asthma and allergy.

Red clover extract: a source for substances that activate peroxisome proliferator-activated receptor alpha and ameliorate the cytokine secretion profile of lipopolysaccharide-stimulated macrophages

OBJECTIVE

Inflammation and hyperlipidemia or dyslipidemia contribute to an increased risk of atherosclerosis and cardiovascular disease. Cardiovascular disease represents one of the major causes of premature death worldwide. The activation of peroxisome proliferator-activated receptor (PPAR) alpha, a drug target for hyperlipidemia and dyslipidemia, leads to an improved blood lipid profile. In this study, we determined the putative anti-inflammatory and PPARalpha stimulatory activities of red clover, an alternative to the classic hormone therapy used currently to treat menopausal symptoms.

METHODS

Lipopolysaccharide-induced macrophages were used as a model for anti-inflammatory activity, and a chimeric GAL4-PPARalpha system was used as a model for putative hypolipidemic activity.

RESULTS

Red clover extract and the isoflavones genistein and biochanin A were moderate PPARalpha activators. Daidzein only slightly activated PPARalpha, but its metabolite 6-hydroxydaidzein exerted a much higher PPARalpha activity. Similarly, the metabolite 3'-hydroxygenistein achieved higher activation efficiency than its precursor, genistein, did. In lipopolysaccharide-stimulated macrophages, red clover extract and its compounds reduced the secretion of proinflammatory cytokines, interleukin-6 and tumor necrosis factor alpha, increased the secretion of the anti-inflammatory interleukin-10, and/or reduced the expression of nuclear factor-kappaB, inducible nitric oxide synthase, and/or cyclooxygenase 2. Tumor necrosis factor alpha production was most efficiently reduced by biochanin A and genistein. Interleukin-6 levels were most efficiently reduced by genistein and equol.

CONCLUSIONS

Owing to its PPARalpha activation and modulation of the secreted cytokine profile, red clover extract is a putative candidate for preventing atherosclerosis and, thus, cardiovascular disease.

The role of protein tyrosine phosphatases in the regulation of allergic asthma: implication of TC-PTP and PTP-1B in the modulation of disease development

Protein tyrosine phosphorylation is an important early event in the signal transduction of numerous cell receptors involved in the immune response. The implication of protein tyrosine kinases in allergic asthma is well recognized, but the role of protein tyrosine phosphatases (PTPs) remains poorly understood. However, we recently reported that global inhibition of PTPs during either the allergen-sensitization phase or the allergen-challenge phase reduced the development of asthma and that this correlated with an increased T helper 1 (Th1) response in both lung and spleen tissues. Therefore, in this study we investigated individual roles of PTPs involved in regulating the immune response. We observed that genetic deficiency for PTP-1B resulted in increased recruitment of lung inflammatory cells, while protein tyrosine phosphatase-phosphatase and tensin homologue deleted (PTP-PEST)-deficient mice exhibited a phenotype similar to that of wild-type mice. Importantly, we found that a heterozygous mutation of T cell PTP (TC-PTP) dramatically abrogates immunoglobulin E production and reduces the recruitment of inflammatory cells to the lung, conferring an important role for TC-PTP in the development of allergic asthma. As opposed to other studies on Src homology phosphatase-1 (SHP-1) deficiency, specific acute SHP-1 inhibition during allergen challenge did not affect disease outcome. Collectively, our results underscore the importance of PTPs in the development of allergic asthma.

Inhibitory effect of n-butanol fraction of Moringa oleifera Lam. seeds on ovalbumin-induced airway inflammation in a guinea pig model of asthma

Moringaceae, which belongs to the Moringa oleifera Lam. family, is a well-known herb used in Asian medicine as an antiallergic drug. In the present study, the efficacy of the n-butanol extract of the seeds of the plant (MONB) is examined against ovalbumin-induced airway inflammation in guinea pigs. The test drugs (MONB or dexamethasone) are administered orally prior to challenge with aerosolized 0.5% ovalbumin. During the experimental period, bronchoconstriction tests are performed, and lung function parameters are measured. The blood and bronchoalveolar lavage fluid are collected to assess cellular content, and serum is used for cytokine (tumor necrosis factor-alpha, interleukin-4, and interleukin-6) assays. Histamine assays of lung tissue are performed using lung tissue homogenate. The results suggest that in ovalbumin-sensitized model control animals, tidal volume is decreased, respiration rate is increased, and both the total and differential cell counts in blood and bronchoalveolar lavage fluid are increased significantly compared with nonsensitized controls. MONB treatment shows improvement in all parameters except bronchoalveolar lavage tumor necrosis factor-alpha and interleukin-4. Moreover, MONB treatment demonstrates protection against acetylcholine-induced bronchoconstriction and airway inflammation. These results indicate that MONB has an inhibitory effect on airway inflammation. Thus, MONB possesses an antiasthmatic property through modulation of the relationship between Th1/Th2 cytokine imbalances.

Preventive and curative glycoside kaempferol treatments attenuate the TH2-driven allergic airway disease

Asthma is a chronic respiratory disease characterized by airway inflammation and airway hyperresponsiveness (AHR). One strategy to treat allergic diseases is the development of new drugs. Flavonoids are compounds derived from plants and are known to have antiallergic, anti-inflammatory, and antioxidant properties. To investigate whether the flavonoid kaempferol glycoside 3-O-[beta-d-glycopiranosil-(1-->6)-alpha-l-ramnopiranosil]-7-O-alpha-l-ramnopiranosil-kaempferol (GRRK) would be capable of modulating allergic airway disease (AAD) either as a preventive (GRRK P) or curative (GRRK C) treatment in an experimental model of asthma. At weekly intervals, BALB/c mice were subcutaneously (sc) sensitized twice with ovalbumin (OVA)/alum and challenged twice with OVA administered intranasally. To evaluate any preventive effect, GRRK was administered 1h (hour) before each OVA-sensitization and challenge, while to analyze the curative effect, mice were first sensitized with OVA, followed by GRRK given at day 18 through 21. The onset of AAD was evaluated 24h after the last OVA challenge. Both treatments resulted in a dose-dependent reduction in total leukocyte and eosinophil counts in the bronchoalveolar lavage fluid (BAL). GRRK also decreased CD4(+), B220(+), MHC class II and CD40 molecule expressions in BAL cells. Histology and lung mechanic showed that GRRK suppressed mucus production and ameliorated the AHR induced by OVA challenge. Furthermore, GRRK impaired Th2 cytokine production (IL-5 and IL-13) and did not induce a Th1 pattern of inflammation. These findings demonstrate that GRRK treatment before or after established allergic lung disease down-regulates key asthmatic features. Therefore, GRRK has a potential clinical use for the treatment of allergic asthma.

Flavonoids as anti-inflammatory agents: implications in cancer and cardiovascular disease

Chronic inflammation is being shown to be increasingly involved in the onset and development of several pathological disturbances such as arteriosclerosis, obesity, diabetes, neurodegenerative diseases and even cancer. Treatment for chronic inflammatory disorders has not been solved, and there is an urgent need to find new and safe anti-inflammatory compounds. Flavonoids belong to a group of natural substances occurring normally in the diet that exhibit a variety of beneficial effects on health. The anti-inflammatory properties of flavonoids have been studied recently, in order to establish and characterize their potential utility as therapeutic agents in the treatment of inflammatory diseases. Several mechanisms of action have been proposed to explain in vivo flavonoid anti-inflammatory actions, such as antioxidant activity, inhibition of eicosanoid generating enzymes or the modulation of the production of proinflammatory molecules. Recent studies have also shown that some flavonoids are modulators of proinflammatory gene expression, thus leading to the attenuation of the inflammatory response. However, much work remains to be done in order to achieve definitive conclusions about their potential usefulness. This review summarizes the known mechanisms involved in the anti-inflammatory activity of flavonoids and the implications of these effects on the protection against cancer and cardiovascular disease.

Effect of Moringa oleifera Lam. seed extract on ovalbumin-induced airway inflammation in guinea pigs

To determine the therapeutic potential of herbal medicine Moringa oleifera Lam. family: Moringaceae in the control of allergic diseases, the efficacy of the ethanolic extract of the seeds of the plant (MOEE) against ovalbumin (OVA)-induced airway inflammation in guinea pigs was examined. During the experimental period, the test drugs (MOEE or dexamethasone) were administered by oral route prior to challenge with aerosolized 0.5% OVA. Bronchoconstriction tests were performed and respiratory parameters (i.e., tidal volume and respiratory rate) were measured. At the end of experiment, blood was collected from each animal to perform total and differential counts and serum was used for assay of IL-4, IL-6, and TNFalpha. Lung lavage fluid (BAL) was collected for estimation of cellular content and cytokine levels. Lung tissue histamine assays were performed using the homogenate of one lobe from each animal; a separate lobe and the trachea were subjected to histopathology to measure the degree of any airway inflammation. The results suggest that in OVA-sensitized control animals that did not receive either drug, tidal volume (V(t)) was decreased, respiration rate (f) was increased, and both the total and differential cell counts in blood and BAL fluid were increased significantly. MOEE-treatment of sensitized hosts resulted in improvement in all parameters except BAL TNFalpha and IL-4. Moreover, MOEE-treatment also showed protection against acetylcholine-induced broncho-constriction and airway inflammation which was confirmed by histological observations. The results of these studies confirm the traditional claim for the usefulness of this herb in the treatment of allergic disorders like asthma.

Soy isoflavones and immunity

The amount of soy products consumed in Japan is much greater than that in Western countries. Recent evidence indicates that soy isoflavones play a beneficial role in obesity, cancer, osteoporosis, and cardiovascular disease. The soybean isoflavone genistein is present at high levels in soy products. Genistein is structurally similar to 17beta-estradiol (E2), and genistein has been suggested to be act as E2 or an antagonist against E2. Genistein suppresses antigen-specific immune response in vivo and lymphocyte proliferation response in vitro. However, genistein enhances the cytotoxic response mediated by NK and cytotoxic T cells and the cytokine production from T cells. Thus, the effect of genistein on immunity is immune cell-dependent. Due to its unique effect on immune function, genistein has been used for the treatment of the diseases in animal models and it has been found that genistein inhibits allergic inflammatory responses. In this review, we summarize current studies related to the effect of isoflavone genistein on the immune system.

Exploring kinase inhibitors as therapies for human arenavirus infections

Arenaviruses are rodent-borne RNA viruses, and some have the capacity to cause hemorrhagic fever and death in infected individuals and thus have been identified as a potential bioterrorism threat. Ribavirin and supportive care are currently the approved therapeutic options for individuals suffering from arenavirus-induced hemorrhagic fever. However, new research has suggested that immune plasma treatment or kinase inhibitors may provide a therapeutic option for treating arenavirus infections in humans. This article puts forth a perspective as to the potential use of kinase inhibitors as an antiviral therapeutic for arenavirus infections.

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.

Genistein treatment of cells inhibits arenavirus infection

Arenaviridae is a family of enveloped viruses some of which are capable of causing hemorrhagic fever syndromes in humans. In this report, we demonstrate that treatment of host cells with the tyrosine kinase inhibitor genistein inhibits infection of cells with the New World arenavirus Pichindé (PICV). The greatest degree of inhibition was observed in pre-treated target cells, but modest inhibition of infection was also seen when drug was added to cultures up to 48h after infection. We show that PICV-induced phosphorylation of the activating transcription factor-2 protein (ATF-2) and cyclic adenosine monophosphate response element binding protein (CREB) is inhibited following genistein treatment. Lastly, genistein treatment also inhibited transduction of cells with pseudotyped retrovirus particles expressing envelope proteins of the Old World arenavirus Lassa virus. These results demonstrate that kinase activity is required for arenavirus infection and that therapeutics designed to inhibit kinase activity should be explored.

The bioavailability and disposition kinetics of genistein in cats

The absorption and disposition kinetics of the soy isoflavone genistein were determined in cats (n = 6). An oral dose of 100 mg/kg was administered, which has previously been demonstrated to be the minimum oral estrogenic dose, and was administered intravenously at a dose of 20 mg/kg, being the largest practical dose that could be safely administered. Plasma free, and total (conjugated + free) genistein concentrations were determined by HPLC following organic extraction. Noncompartmental analysis revealed a half-life of 21.67 +/- 7.9 h (free) and 9.95 +/- 2.7 h (conjugated), volume of distribution 31.94 +/- 10.38 L/kg (free) and 11.82 +/- 3.96 L/kg (conjugated) following intravenous administration. Following oral administration the half-lives were determined to be 17 +/- 4.8 h (free) and 8.56 +/- 4.65 h (conjugated), with tmax = 4.4 +/- 0.6 h (free) and 4.42 +/- 0.99 h (conjugated), and Cmax = 0.276 +/- 0.1 microg/mL (free) and 6.24 +/- 6.58 microg/mL (conjugated). Oral bioavailabilities were 1.379 +/- 0.9% (free) and 29.85 +/- 22.61% (conjugated). The ratio of total:free genistein ranged from 25.9 to 5.5. Poor oral absorption and efficient conjugation explain the low bioavailability of free genistein. Accumulation of genistein in peripheral lipophilic compartments may occur.

NV-52

NV-52, a synthetic flavonoid derivative, is a selective thromboxane synthase (TXS) inhibitor that is being developed as a treatment for inflammatory bowel disease. NV-52 selectively inhibits TXS in vitro in physiological relevant concentrations, causing a reduction in thromboxane B(2) of </= 40% in association with an increase in prostaglandin E(2). NV-52 is effective in suppressing colonic inflammation in a murine model of inflammatory bowel disease. NV-52 has not demonstrated any toxicity in in vitro and animal toxicological studies, and has been administered to normal volunteers in a Phase I clinical trial without detectable adverse effects. NV-52 is well absorbed and a single dose of 400 mg p.o. produced a plasma concentration that is comparable with the concentrations that have been shown to produce significant TXS inhibition in vitro.

Airway hyper-responsiveness in allergic asthma in guinea-pigs is mediated by nerve growth factor via the induction of substance P: a potential role for trkA

BACKGROUND

The neurotrophin nerve growth factor (NGF) has been implicated as a mediator in allergic asthma. Direct evidence that inhibition of NGF-induced activation of neurotrophin receptors leads to improvement of airway symptoms is lacking. We therefore studied the effects of inhibitors of NGF signal transduction on the development of airway hyper-responsiveness (AHR) and pulmonary inflammation in a guinea-pig model for allergic asthma.

METHODS

Airway responsiveness to the contractile agonist histamine was measured in vivo in guinea-pigs that were sensitized and challenged with ovalbumin (OVA). Inflammatory cell influx and NGF levels were determined in bronchoalveolar lavage fluid (BALF). Substance P, a key mediator of inflammation, was measured in lung tissue by radioimmunoassay, while substance P immunoreactive neurons in nodose ganglia were measured by immunohistochemistry.

RESULTS

OVA challenge induced an AHR after 24 h in OVA-sensitized guinea-pigs. This coincided with an increase in the amount of NGF in BALF. Simultaneously, an increase in the percentage of substance P immunoreactive neurons in the nodose ganglia and an increase in the amount of substance P in lung tissue were found. We used tyrosine kinase inhibitors to block the signal transduction of the high-affinity NGF receptor, tyrosine kinase A (trkA). Treatment with the tyrosine kinase inhibitors (K252a or tyrphostin AG879) both inhibited the development of AHR, and prevented the increase in substance P in the nodose ganglia and lung tissue completely whereas both inhibitors had no effect on baseline airway resistance. Neither treatment with K252a or tyrphostin AG879 changed the influx of inflammatory cells in the BALF due to allergen challenge.

CONCLUSIONS

We conclude that substance P plays a role in the induction of AHR in our model for allergic asthma which is most likely mediated by NGF. As both tyrosine kinase inhibitors AG879 and K252a show a similar inhibitory effect on airway function after allergen challenge, although both tyrosine kinase inhibitors exhibit different non-specific inhibitory effects on targets other than trkA tyrosine kinases, it is likely that the induction of substance P derived from sensory nerves is mediated by NGF via its high-affinity receptor trkA.

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.

Montelukast prevents the decrease of interleukin-10 and inhibits NF-kappaB activation in inflammatory airway of asthmatic guinea pigs

Interleukin (IL)-10 is an important immunoregulatory and anti-inflammatory cytokine, whereas nuclear factor-kappaB (NF-kappaB) plays an important role in the pathogenesis of asthma. In the present study, the effects of montelukast on the level of IL-10 and on the activation of NF-kappaB in the inflammatory airway of asthmatic guinea pigs were investigated. Guinea pigs were sensitized by ovalbumin. Pulmonary inflammation was observed by hematoxylin and eosin staining. The eosinophils in broncho-alveolar lavage fluid and blood were separated by density gradient centrifugation and counted under microscope. The level of IL-10 in broncho-alveolar lavage fluid was measured by enzyme-linked immunoadsorbent assay. Activation of NF-kappaB in lung tissues was inspected by immunohistochemistry. Montelukast at medium and high doses prevented the decrease of IL-10 in broncho-alveolar lavage fluid (n = 8, p < 0.01 vs. asthma model group), inhibited the activation of NF-kappaB in lung tissues (n = 8; medium dose, p < 0.05; high dose, p < 0.01; vs. asthma model group). There was a significantly negative correlation between the level of IL-10 and the activation of NF-kappaB in lung tissues (r = -0.488, p < 0.01). Montelukast reduced the severity of airway inflammation and the number of eosinophils in asthmatic guinea pigs. From all these findings we conclude that montelukast can prevent the decrease of IL-10 and inhibit the activation of NF-kappaB in inflammatory airway of asthmatic guinea pigs, which may be the new important mechanisms of montelukast's anti-airway-inflammation effects in asthmatic guinea pigs.

Soy consumption and mortality in Hong Kong: proxy-reported case-control study of all older adult deaths in 1998

OBJECTIVES

This study investigates the relation between soy consumption and mortality in a population-based case-control study in Hong Kong of all adult deaths in 1998.

METHODS

Multivariable logistic regression was used to assess the effect of soy on all-cause and cause-specific mortality in 21,494 deceased cases and 10,968 living controls who were ethnic Chinese aged 60 or above, using proxy reports collected from the person registering the death. Dietary habits were obtained from proxies in both cases and controls, based on a 7-item questionnaire.

RESULTS

The adjusted odds ratios for all-cause mortality for soy consumption 4 or more times a week compared with less than once a month were 0.77 (95% CI: 0.62, 0.95) for men and 0.66 (0.54, 0.81) for women. Mortality from lung cancer (males P = 0.02, females P = 0.02), colorectal cancer (males P = 0.07, females P < 0.001), stomach cancer (males P = 0.04, females P = 0.03), female breast cancer (P = 0.02) and ischemic heart disease (males P < 0.001, females P = 0.002) was inversely associated with soy consumption.

CONCLUSIONS

Our study suggests that maintaining traditional levels of soy consumption could be protective for some chronic diseases in China.

Targeting kinases in asthma

Through a regulation cascade via the site-specific phosphorylation of downstream substrates, members of kinase signaling pathways play multiple cellular regulatory roles. Because of the contribution of kinases in a diverse number of cellular processes, members of these pathways have become attractive targets for rational drug design. Members of these kinase signalling families, such as mitogen-activated kinases, tyrosine kinases (receptor and non-receptor) and ras human orthologue kinases among others have been shown to play key roles in the pathogenesis of immune, inflammatory and remodelling events that occur during asthma. This review highlights, through information that has been obtained from transgenic and knockout systems, small-molecule inhibitors and antisense technology, the role of select members of kinase families in the pathogenesis of asthma, and discusses the rationale for developing specific inhibitors of these kinases for the treatment of asthma.

Modulation of eosinophil generation and migration by Mangifera indica L. extract (Vimang)

The effects of Vimang, an aqueous extract of the stem bark of Mangifera indica L. (Anacardiaceae), on cell migration in an experimental model of asthma was investigated. In vivo treatment of Toxocara canis-infected BALB/c mice for 18 days with 50 mg/kg Vimang reduced eosinophil migration into the bronchoalveolar space and peritoneal cavity. Also, eosinophil generation in bone marrow and blood eosinophilia were inhibited in infected mice treated with Vimang. This reduction was associated with inhibition of IL-5 production in serum and eotaxin in lung homogenates. In all these cases the effects of Vimang were more selective than those observed with dexamethasone. Moreover, Vimang treatment is not toxic for the animals, as demonstrated by the normal body weight increase during infection. These data confirm the potent anti-inflammatory effect of Vimang and support its potential use as an alternative therapeutic drug to the treatment of eosinophilic disorders including those caused by nematodes and allergic diseases.

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.

Fc receptors as determinants of allergic reactions

Activation of the high-affinity receptor for IgE (FcepsilonRI) on allergic effector cells induces a multitude of positive signals via immunoreceptor tyrosine-based activation motifs, which leads to the rapid manifestation of allergic inflammatory reactions. As a counterbalance, the coaggregation of the IgG receptor FcgammaRIIB mediates inhibitory signals via immunoreceptor tyrosine-based inhibition motifs. Advances in the positive and negative regulation of Fc receptor expression and signaling have shed light on the role of Fc receptors in our immune system, indicating them to be bifunctional, inhibitory and activating structures. Based on these findings, exciting new therapeutic strategies have been developed, such as the use of chimeric fusion proteins, which concomitantly activate FcepsilonRI and FcgammaRIIB. These new approaches successfully take advantage of the bivalent character of Fc receptors and pave the way for innovative strategies to modulate allergic immune reactions.

Changes in gene expressions elicited by physiological concentrations of genistein on human endometrial cancer cells

The incidence of hormone-related diseases such as prostatic, breast, ovarian, and endometrial cancer is lower in Asian populations compared to Western countries. High consumption of soybean products that are rich in phytoestrogens, predominantly genistein, is postulated to be responsible for the lower incidence of hormone-related disease, although the mechanism through which this effect might be mediated is unclear. In this study, microarray analysis was used to identify the changes in gene expression elicited by treatment of the human endometrial cancer cell line, Ishikawa, with genistein at both physiologically achievable and supraphysiological concentrations. Genistein treatment at 5 microM concentration induced multiple changes in gene expression including some implicated in oncogenesis. In contrast, treatment with a supraphysiological concentration of genistein predominantly activated stress response genes and showed very limited overlap with the genes regulated at lower concentrations. Of the genes regulated by genistein, 9.3% were also regulated by 17beta-estradiol suggesting that genistein exerts its response via the estrogen pathway. These results indicate that at physiological concentrations, genistein is able to elicit pleiotropic effects on a variety of pathways believed to be involved in tumorigenesis. Supraphysiological concentrations of genistein, such as those used in many previous studies, elicit changes in gene expression that are unlikely to occur in vivo.

Genistein Suppresses Development of Spontaneous Atopic-Like Dermatitis in NC/Nga Mice

In this study, we examined the effect of genistein on the severity of dermatitis and level of serum IgE in NC/Nga (NC) mice. NC mice housed in conventional conditions develop spontaneous atopic-like dermatitis; however, oral administration of 20 mg/kg genistein suppresses the development of dermatitis. We also investigated the levels of serum IgE in genistein-treated NC mice and found that the levels were the same as those in control NC mice. We further investigated in vitro IFN-gamma and IL-4 production from spleen cells upon stimulation with anti-CD3 and anti-CD28 mAbs. IFN-gamma production level in NC mice that received 20 mg/kg genistein was significantly lower than that in control NC mice. In contrast, the production level of IL-4 in genistein-treated mice was not significantly different from that in control mice but tended to increase in a dose-dependent manner.

Antagonistic effects of nobiletin, a polymethoxyflavonoid, on eosinophilic airway inflammation of asthmatic rats and relevant mechanisms

Eosinophils are known to be the important effector cells in asthmatic airway inflammation. The purpose of this study was to investigate the effects of nobiletin, a polymethoxyflavonoid, on eosinophilic airway inflammation of asthmatic rats, and explore its possible mechanisms. Animals were actively sensitized by subcutaneous injection of ovalbumin (OVA). The inflammation in lung tissues of asthmatic rats was observed by hematoxylin and eosin (HE) staining. The eosinophils in blood and BALF were separated by Percoll density gradient centrifugation and counted under microscope. The level of Eotaxin was detected by enzyme-linked immunosorbent assay (ELISA). In addition, the apoptosis of eosinophils was labeled by TdT-mediated dUTP nick end labeling (TUNEL) technique, the semi-quantitative detection for Fas mRNA expression of eosinophils was performed by reverse transcription-polymerase chain reaction (RT-PCR). The airway inflammation of asthmatic rats pretreated with nobiletin was obviously alleviated. Nobiletin (1.5 and 5.0 mg/kg given intraperitoneally) significantly reduced OVA-induced increases in eosinophils, remarkably lowered the level of Eotaxin in blood and broncho-alveolar lavage fluid (BALF) of asthmatic rats. On the other hand, semi-quantitative RT-PCR analysis for Fas of eosinophils from OVA aerosol-challenged sensitized rats showed that Fas mRNA expression of eosinophils was obviously enhanced by nobiletin. Meanwhile, the apoptosis index of cultured eosinophils was significantly elevated after treatment with different doses of nobiletin. These results indicated that nobiletin could inhibit the eosinophilic airway inflammation. Lowering the levels of Eotaxin, relieving airway infiltration of eosinophils and promoting apoptosis of eosinophils by enhancing expression of Fas mRNA may be important mechanisms for nobiletin to antagonize eosinophilic airway inflammation of asthmatic rats.

Detection of nanometer-sized particles in living cells using modern fluorescence fluctuation methods

Nanosized materials are increasingly used in medicine and biotechnology but originate also from various aerosol sources. A detailed understanding of their interaction with cells is a prerequisite for specific applications and appraisal of hazardous effects. Fluorescence fluctuation methods are applied to follow the time-course of the translocation and distribution of fluorescent 20 nm polystyrene nanoparticles with negative surface charges in HeLa cells under almost physiological conditions. The experimental results demonstrate that singular particles enter the cell without significant contribution by endocytotic mechanisms and are distributed within the cytoplasm. Subsequently aggregation is observed, which can be blocked by cytotoxins, like Genistein and Cytochalasin B, interfering with cellular uptake processes. The observed non-active uptake is due to non-specific interactions with the cell surface and could be responsible for distribution of nanometer-sized materials in tissue.

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

To determine if micronutrient intake is associated with asthma severity, we administered the Block food frequency questionnaire to participants in a randomized clinical trial of the safety of influenza vaccine for asthmatics. The nutrition substudy included 1033 participants, aged 12-75. Intake of antioxidant vitamins, soy isoflavones, total fruits and vegetables, fats, and fiber was compared with asthma severity at baseline [forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEF), asthma symptoms] and the rate of asthma exacerbations during the 2 weeks following influenza vaccination. The only nutrient that had a consistent association with asthma severity was genistein, a soy isoflavone. None of the nutrients evaluated were related to asthma exacerbation rate when adjusted for known confounders. The FEV1 in genistein consumers of at least 250 microg/1000 Kcal/day was 82.1% predicted, 79.9% predicted for those who consumed between 1 and 249 microg/1000 kcal, and 76.2% predicted in genistein nonconsumers (p=0.006); the PEF was 82.7% predicted, 80.8% predicted, and 78.3% predicted, respectively (p=0.009). There were no differences in the Asthma Symptom Utility Index (ASUI). We could not account for these results based on differences in demographics, body mass index, or consumption of other nutrients. Thus, increasing consumption of genistein is associated with better lung function in patients with asthma. Further studies are needed to determine whether dietary supplementation with genistein can reduce asthma severity.

Dietary fiber and reduced cough with phlegm: a cohort study in Singapore

Smoking is the major risk factor for chronic respiratory symptoms, but dietary factors may also play a role. Most studies of diet and lung disease have been cross-sectional and conducted in populations with a Western-style diet. We analyzed the relation between dietary intake at baseline and new onset of cough with phlegm in a population-based cohort of 63,257 middle-aged Chinese men and women initiated in Singapore between 1993 and 1998. Beginning in 1999, we ascertained respiratory symptoms by telephone interview and have identified 571 incident cases of cough with phlegm among the 49,140 cohort members with completed follow-up. Nonstarch polysaccharides, a major component of dietary fiber, total fruit, and soy isoflavones had the strongest associations. Odds ratios comparing highest and lowest quartiles after adjustment for age, sex, dialect group, total energy intake, and smoking were 0.61 (95% confidence interval [CI]: 0.47, 0.78; p for trend < 0.001) for nonstarch polysaccharides, 0.67 (95% CI: 0.52, 0.87; p for trend = 0.006) for fruit, and 0.67 (95% CI: 0.53, 0.86; p for trend = 0.001) for soy isoflavones. These data suggest that a diet high in fiber from fruit and, possibly, soyfoods may reduce the incidence of chronic respiratory symptoms. Associated nutrients, such as flavonoids, may contribute to this association.

Tyrosine kinase inhibitors: a new approach for asthma

The pathogenesis of allergic asthma involves the interplay of inflammatory cells and airway-resident cells, and of their secreted mediators including cytokines, chemokines, growth factors and inflammatory mediators. Receptor tyrosine kinases are important for the pathogenesis of airway remodeling. Activation of epidermal growth factor (EGF) receptor kinase and platelet-derived growth factor (PDGF) receptor kinase leads to hyperplasia of airway smooth muscle cells, epithelial cells and goblet cells. Stimulation of non-receptor tyrosine kinases (e.g. Lyn, Lck, Syk, ZAP-70, Fyn, Btk, Itk) is the earliest detectable signaling response upon antigen-induced immunoreceptor activation in inflammatory cells. Cytokine receptor dimerization upon ligand stimulation induces activation of Janus tyrosine kinases (JAKs), leading to recruitment and phosphorylation of signal transducer and activator of transcription (STAT) for selective gene expression regulation. Activation of chemokine receptors can trigger JAK-STAT pathway, Lck, Fyn, Lyn, Fgr, and Syk/Zap-70 to induce chemotaxis of inflammatory cells. Inhibitors of tyrosine kinases have been shown in vitro to block growth factor-induced hyperplasia of airway-resident cells; antigen-induced inflammatory cell activation and cytokine synthesis; cytokine-mediated pro-inflammatory gene expression in inflammatory and airway cells; and chemokine-induced chemotaxis of inflammatory cells. Recently, anti-inflammatory effects of tyrosine kinase inhibitors (e.g. genistein, tyrphostin AG213, piceatannol, tyrphostin AG490, WHI-P97, WHI-P131, Syk antisense) in animal models of allergic asthma have been reported. Therefore, development of inhibitors of tyrosine kinases can be a very attractive strategy for the treatment of asthma.

Effect of Red Clover Isoflavones on Cox-2 Activity in Murine and Human Monocyte/Macrophage Cells

Long-term use of nonsteroidal anti-inflammatory drugs is associated with a reduction in the incidence of a range of cancers, the mechanism of which is thought to be cyclooxygenase (COX) inhibition. Because long-term ingestion of foods rich in isoflavones, such as legumes (beans, peas, lentils) has been associated with reduced cancer incidence, it was considered useful to examine the COX-inhibitory activities of individual isoflavones. Red clover dietary supplements also contain varying ratios of the 4 isoflavones commonly found in legume-based diets, namely, daidzein, genistein, formononetin, and biochanin. Using 2 separate cell assays, this study examined the ability of the isoflavones found in red clover to inhibit COX enzyme activity in both the murine macrophage cell line RAW 264.7 and human monocytes. Within the range of 1-40 microM in RAW 264.7 cells and 10-100 microM in human monocytes, isoflavones were able to reduce significantly the synthesis of prostaglandin E2 and/or thromboxane B2 (P < 0.001 to P < 0.05), indicating COX inhibition. Thus, it is possible that the lower rates of some cancers in populations with a high intake of dietary isoflavones is linked to their inhibition of COX activity.