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Biomedical subjects

Peter J Barnes

Publications and source records attributed to Peter J Barnes.

At least 145 records · Page 8Linked to original sources
PubMed2002

Analysis of expired air for oxidation products.

Chronic inflammation is a critical feature of chronic obstructive pulmonary disease, cystic fibrosis, and asthma. This inflammation is associated with the increased production of reactive oxygen species or oxidative stress in the lungs. Oxidative stress may have several adverse effects and may amplify the inflammatory process; however, monitoring oxidative stress is difficult and may not be reflected by changes in blood markers. We have therefore developed several noninvasive markers in the exhaled breath that may indicate oxidative stress in the lungs, and we studied these in relationship to the severity of chronic inflammatory lung diseases. We analyzed the exhaled breath for the content of nitric oxide as a marker of inflammation, carbon monoxide as a marker of oxidative stress, and ethane, which is one of the end products of lipid peroxidation. In addition, we measured the concentration of markers of oxidative stress such as isoprostanes in exhaled breath condensate. Our results confirm that there are increased inflammation, oxidative stress, and lipid peroxidation in lung disease, as shown by elevated levels of nitric oxide, carbon monoxide, and ethane, respectively. The finding of lower levels of these gases in patients on steroid treatment and of higher levels in those with more severe lung disease, as assessed by lung function tests and clinical symptoms, reinforces the hypothesis that the noninvasive measurement of exhaled gases maybe useful in monitoring the underlying pathologic pathways of lung disease. Longitudinal studies are required to assess the clinical usefulness of these measurements in the monitoring of chronic inflammatory lung disease.

Asthma↗
PubMed2002

Ozone-induced increase in exhaled 8-isoprostane in healthy subjects is resistant to inhaled budesonide.

The aim of this study was to quantify lung oxidant stress after short-term ozone exposure as reflected by 8-isoprostane concentrations in exhaled breath condensate (EBC) and to investigate the effects of inhaled budesonide on this response. 8-Isoprostane is a prostaglandin-F(2 alpha) isomer that is formed in vivo by free radical-catalyzed peroxidation of arachidonic acid. EBC is a noninvasive method to collect airway secretions. We undertook a double-blind, randomized, placebo-controlled, crossover study with inhaled budesonide (800 microg) or placebo twice daily for 2 weeks prior to ozone exposure (400 parts per billion) for 2 h in nine healthy nonsmokers. Exhaled 8-isoprostane was measured by an enzyme immunoassay. 8-Isoprostane was increased 4 h after ozone exposure compared to pre-exposure values in both placebo (36.9 +/- 3.9 pg/ml, mean +/- SEM, vs. 16.9 +/- 0.7 pg/ml; p <.001) and budesonide groups (33.4 +/- 2.6 pg/ml vs. 15.8 +/- 0.3 pg/ml; p <.001). Pretreatment with budesonide did not affect the increases in 8-isoprostane (mean differences 3.4 pg/ml, 95% CI -8.9 to 15.7, p =.54). Short-term ozone exposure causes acute increase in lung oxidative stress as reflected by exhaled 8-isoprostane. This increase is resistant to pretreatment with a high dose of inhaled budesonide.

Adult↗
PubMed2002

Ubiquitous expression of phosphodiesterase 7A in human proinflammatory and immune cells.

We have determined the expression of phosphodiesterase (PDE) 7A1 and PDE7A2 in human cells that have been implicated in the pathogenesis of chronic obstructive pulmonary disease and asthma. Messenger RNA transcripts were detected by RT-PCR in T lymphocytes, monocytes, neutrophils, airway and vascular smooth muscle cells, lung fibroblasts, epithelial cells, and cardiac myocytes. Human epithelial, T cell, eosinophil, and lung fibroblast cell lines were also positive for PDE7A1 and PDE7A2 mRNA transcripts. By Western immunoblot analyses the amount of PDE7A1 was greatest in T cell lines, peripheral blood T lymphocytes, epithelial cell lines, airway and vascular smooth muscle cells, lung fibroblasts, and eosinophils but was not detected in neutrophils. In contrast, PDE7A2 protein, which was identified in human cardiac myocytes, was not found in any of the other cell types investigated. Immunoconfocal analyses showed that PDE7A was expressed in neutrophils and alveolar macrophages. As the expression of PDE7A mirrors the distribution of PDE4 we speculate that this enzyme could be a target for novel anti-inflammatory drugs.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2002

Role of nitric oxide in allergic inflammation and bronchial hyperresponsiveness.

The role of nitric oxide (NO) in allergic inflammation and bronchial hyperresponsiveness is unclear. We studied a selective prodrug nitric oxide synthase (NOS)-2 inhibitor, L-N(6)-(1-iminoethyl)lysine 5-tetrazole amide (SC-51). In ovalbumin-sensitized and challenged rats, exhaled NO levels increased by 3 h following challenge (3.73 +/- 0.74 ppb; P < 0.05), peaking at 9 h (11.0 +/- 2.75; P < 0.01) compared to saline controls (1.87 +/- 0.26; P < 0.05 and 2.81 +/- 0.18; P < 0.01). Immunoreactive lung NOS2 expression was increased in ovalbumin-challenged rats compared with ovalbumin-sensitized, saline-challenged rats at 8 h post-challenge. SC-51 (10 mg/kg; p.o.) inhibited allergen-induced increase in exhaled NO levels to 1.3 +/- 0.17 ppb. SC-51 inhibited bronchial hyperresponsiveness in ovalbumin-sensitized and challenged rats (P < 0.05). In sensitized non-exposed rats, SC-51 increased bronchial responsiveness (P < 0.05). SC-51 reduced the allergen-induced increase in bronchoalveolar lavage neutrophils, but caused a nonsignificant reduction in bronchial mucosal eosinophil numbers. NO generated through NOS2 contributes to allergen-induced bronchial hyperresponsiveness but not to bronchial eosinophilia, indicating that these are independently expressed.

Acetylcholine↗
PubMed2002

Impaired inhibition by dexamethasone of cytokine release by alveolar macrophages from patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is characterized by inflammation of the respiratory tract in which macrophages are the predominant inflammatory cell and for which the efficacy of treatment with corticosteroids is controversial. We investigated the effect of dexamethasone on basal and interleukin (IL)-1beta or cigarette smoke media (CSM)-stimulated release of IL-8 and granulocyte macrophage-colony stimulating factor (GM-CSF) by bronchoalveolar lavage macrophages from cigarette smokers and patients with COPD (n = 15). Basal release of IL-8 was approximately fivefold greater in patients with COPD than smokers, whereas GM-CSF was similar for each group. IL-1beta and CSM increased IL-8 and GM-CSF release by macrophages from both smokers and patients with COPD. Dexamethasone did not inhibit basal or stimulated IL-8 release from macrophages from patients with COPD but inhibited release in smokers. In contrast, basal and IL-1beta-stimulated GM-CSF release, but not CSM-stimulated release, was inhibited by dexamethasone. We conclude that the lack of efficacy of corticosteroids in COPD might be due to the relative steroid insensitivity of macrophages in the respiratory tract.

Aged↗
PubMed2002

Increased leukotrienes in exhaled breath condensate in childhood asthma.

Cysteinyl leukotrienes (cys-LTs; LTC4, LTD4, and LTE4) are generated predominantly by mast cells and eosinophils and induce airway smooth muscle contraction, microvascular leakage, and mucous hypersecretion whereas leukotriene B4 (LTB4) is a potent chemoattractant of neutrophils. We measured cys-LTs and LTB4 in exhaled breath condensate from children aged 7-14 years including healthy nonatopic children (n = 11) and children with mild intermittent asthma (steroid naive, n = 11), mild persistent asthma (low-dose inhaled steroid treatment, n = 13), or moderate to severe persistent asthma (high-dose inhaled steroid treatment, n = 13). Exhaled LTB4 levels were increased in patients with mild and moderate to severe persistent asthma compared with patients with mild intermittent asthma (126.0 +/- 8.8 and 131.9 +/- 7.1 versus 52.7 +/- 3.8 pg/ml, p < 0.001 and p < 0.0001) and normal subjects (126.0 +/- 8.8 and 131.9 +/- 7.1 versus 47.9 +/- 4.1 pg/ml, p < 0.0001). Elevated exhaled cys-LT levels were found in patients with mild and moderate to severe persistent asthma compared with normal subjects (27.9 +/- 2.8 and 31.5 +/- 4.5 versus 18.5 +/- 0.5 pg/ml, p < 0.01 and p < 0.05). There was an inverse correlation between exhaled cys-LTs and LTB4 in patients with mild persistent asthma. We conclude that exhaled cys-LTs and LTB4 may be noninvasive markers of airway inflammation in pediatric asthma.

Adolescent↗
PubMed2002

Increased p21(CIP1/WAF1) and B cell lymphoma leukemia-x(L) expression and reduced apoptosis in alveolar macrophages from smokers.

Alveolar macrophages (AMs) are the predominant defense cells in the airway, and their numbers are increased in smokers and subjects with chronic obstructive pulmonary disease. This increase may result from increased recruitment, increased proliferation, or reduced cell death. Apoptosis regulates inflammatory cell survival, and p21(CIP1/WAF1) is an important inhibitory regulator of cycle progression after oxidative stress. We have investigated whether chronic smoke exposure influences the expression and localization of cell cycle and apoptotic proteins in AM and bronchial epithelial cells in vivo. The increased numbers of AMs seen in smokers were only partially due to enhanced proliferation. p21(CIP1/WAF1) protein expression was increased in AMs and biopsies isolated from smokers and was found predominantly within the cytoplasm. In addition, B cell lymphoma leukemia (Bcl)-x(L), an antiapoptotic regulator, was also highly expressed in macrophages from smokers compared with nonsmokers and subjects with asthma. Hydrogen peroxide, an oxidative stress, induced cytoplasmic expression of p21(CIP1/WAF1) and failed to induce apoptosis in an in vitro model. These results suggested that AM and bronchial epithelial cells from smokers, in contrast to those from normal subjects and subjects with asthma, have reduced cell death. Thus, oxidative stress induced by cigarette smoking may contribute to the chronicity of inflammation in the airway, through a reduction of apoptosis.

Adult↗
PubMed2002

Increased exhaled cysteinyl-leukotrienes and 8-isoprostane in aspirin-induced asthma.

The pathogenesis of aspirin-induced asthma (AIA) has not yet been clearly elucidated, although eicosanoid metabolites appear to play an important role. We hypothesized that levels of eicosanoids in exhaled air condensate are abnormal in patients with AIA and that they change in patients receiving steroid therapy. We measured cysteinyl-leukotrienes (cys-LTs), prostaglandin E(2) (PGE(2)), and leukotriene B(4) (LTB(4)), and also 8-isoprostane as a marker of oxidative stress, by enzyme immunoassay in exhaled breath condensate from patients with AIA (17 steroid naive; mean age, 41 +/- 23 years; FEV(1), 63%pred), 26 patients with aspirin-tolerant asthma (ATA) (11 steroid naive; mean age, 47 +/- 18 years; FEV(1), 69%pred), and 16 healthy subjects (mean age, 45 +/- 17 years; FEV(1), 93%pred). Cys-LTs were significantly higher in steroid-naive patients with AIA compared with steroid-naive patients with ATA and healthy subjects (152.3 +/- 30.4 and 36.6 +/- 7.1 versus 19.4 +/- 2.8 pg/ml; p < 0.05 and p < 0.05, respectively). Steroid-naive patients with AIA also had higher levels of 8-isoprostane than normal subjects (131.8 +/- 31.0 versus 21.9 +/- 4.5 pg/ml; p < 0.05). There were significantly lower levels of both cys-LTs and 8-isoprostanes in steroid-treated patients with AIA. There was no difference in either the PGE(2) or LTB(4) level between the patient groups. This is the first study to show that cys-LTs and 8-isoprostanes are elevated in expired breath condensate of steroid-naive patients with AIA, and that cys-LTs are decreased in steroid-treated patients. Exhaled PGE(2) levels are not reduced, so that it is unlikely that a deficiency of PGE(2) is an important mechanism, whereas exhaled LTB(4) levels are unchanged, indicating an abnormality beyond 5-lipoxygenase.

Adult↗
PubMed2002

Expression and activity of histone deacetylases in human asthmatic airways.

Asthma is a chronic inflammatory disease that is characterized by increased expression of multiple inflammatory genes. Chromatin modification plays a critical role in the regulation of these genes. Acetyaltion of histones by histone acetyltransferases (HATs) is associated with increased gene transcription, whereas hypocetylation induced by histone deacetylases (HDACs) is associated with suppression of gene expression. We have examined the expression and activity of HATs and HDACs in bronchial biopsies from normal subjects and subjects with asthma. There was no difference in the site of HDAC1-HDAC6 expression between normal subjects and subjects with asthma, but subjects with asthma had reduced HDAC enzymatic activity and reduced HDAC1 and HDAC2 protein expression, as measured by Western blotting. In contrast, subjects with asthma treated with inhaled steroids were found to have greater HDAC activity than untreated subjects with asthma, although still lower than control subjects. In contrast, although there was no change in the site of HAT (CREB binding protein and p300/CREB binding protein-associated factor) expression, HAT activity was increased in subjects with asthma. HAT activity was reduced to control levels in subjects with asthma treated with inhaled steroids. The increase in HAT activity and reduced HDAC activity in asthma may underlie the increased expression of multiple inflammatory genes, and this is reversed, at least in part, by treatment with inhaled steroids.

Administration, Inhalation↗
PubMed2002

A molecular mechanism of action of theophylline: Induction of histone deacetylase activity to decrease inflammatory gene expression.

The molecular mechanism for the anti-inflammatory action of theophylline is currently unknown, but low-dose theophylline is an effective add-on therapy to corticosteroids in controlling asthma. Corticosteroids act, at least in part, by recruitment of histone deacetylases (HDACs) to the site of active inflammatory gene transcription. They thereby inhibit the acetylation of core histones that is necessary for inflammatory gene transcription. We show both in vitro and in vivo that low-dose theophylline enhances HDAC activity in epithelial cells and macrophages. This increased HDAC activity is then available for corticosteroid recruitment and predicts a cooperative interaction between corticosteroids and theophylline. This mechanism occurs at therapeutic concentrations of theophylline and is dissociated from phosphodiesterase inhibition (the mechanism of bronchodilation) or the blockade of adenosine receptors, which are partially responsible for its side effects. Thus we have shown that low-dose theophylline exerts an anti-asthma effect through increasing activation of HDAC which is subsequently recruited by corticosteroids to suppress inflammatory genes.

Adult↗
PubMed2002

Responses of leukocytes to chemokines in whole blood and their antagonism by novel CC-chemokine receptor 3 antagonists.

CC-chemokine receptor 3 (CCR3)-stimulating chemokines are likely to have important in vivo roles in the regulation of eosinophil, basophil, and potentially helper T cell type 2 and mast cell recruitment. We have developed techniques to investigate the actions of eotaxin and other chemokines on multiple leukocyte populations in whole blood, without cell purification steps that might alter leukocyte responsiveness. We have shown that the potency of eotaxin in whole blood is limited by Duffy antigen binding, which may modulate the actions of this chemokine in vivo. We have also investigated the efficacy and potency of a new panel of small molecule antagonists of CCR3 on responses of eosinophils, neutrophils, basophils, and monocytes to chemokines, using whole blood assays of shape change, chemokine receptor internalization, and CD11b upregulation. These small molecule antagonists cause selective and potent inhibition of CCR3 on eosinophils and basophils, are bioavailable in blood, and are prototypic antagonists potentially of benefit in the treatment of human allergic disease. Such whole blood methods may also be employed in the investigation of other small molecule chemokine receptor antagonists.

Chemokines, CC↗
PubMed2002

Effect of theophylline on induced sputum inflammatory indices and neutrophil chemotaxis in chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is characterized by a neutrophilic airway inflammation that can be demonstrated by examination of induced sputum. Theophylline has antiinflammatory effects in asthma, and in the present study we investigated whether a similar effect occurs in COPD patients treated with low doses of theophylline. Twenty-five patients with COPD were treated with theophylline (plasma level of 9-11 mg/L) for 4 weeks in a placebo-controlled, randomized, double-blind crossover study. Theophylline was well tolerated. Induced sputum inflammatory cells, neutrophils, interleukin-8, myeloperoxidase, and lactoferrin were all significantly reduced by about 22% by theophylline. Neutrophils from subjects treated with theophylline showed reduced chemotaxis to N-formyl-met-leu-phe (approximately 28%) and interleukin-8 (approximately 60%). Neutrophils from a healthy donor showed reduced chemotaxis (approximately 30%) to induced sputum samples obtained during theophylline treatment. These results suggest that theophylline has antiinflammatory properties that may be useful in the long-term treatment of COPD.

Aged↗
PubMed2002

Increased interleukin-4 and decreased interferon-gamma in exhaled breath condensate of children with asthma.

Exhaled breath condensate analysis for noninvasive quantification of airway inflammation in asthma is a potentially useful research tool in children. There is an imbalance between T-helper (Th)-2 cells, which secrete interleukin (IL)-4, and Th1 cells, which secrete interferon (IFN)-gamma, in asthma. We measured concentrations of IL-4 and IFN-gamma in breath condensates of 37 children (11 normal, 12 steroid-naive, and 14 steroid-treated children with asthma). Exhaled IFN-gamma was significantly lower in steroid-naive and steroid-treated children with asthma compared with normal control subjects (3.7 +/- 0.2 versus 5.1 +/- 0.4 pg/ml, p < 0.01 and 4.1 versus 5.1 pg/ml, p < 0.05). By contrast, mean exhaled IL-4 was elevated in asthma (53.7 +/- 4.2 pg/ml) compared with normal children (35.7 +/- 6.2 pg/ml, p < 0.05) and concentrations were lower with steroid treatment (37.5 +/- 5.6 pg/ml, p < 0.05). Exhaled IL-4 was significantly lower in children with asthma on more than 600 microg inhaled steroid/day. The IL-4/IFN-gamma ratio was significantly greater in children with asthma compared with control children and the children with asthma on inhaled steroid therapy. We have shown for the first time that IFN-gamma and IL-4 can be assayed in exhaled breath condensate and shows an increased ratio of IL-4/IFN-gamma, consistent with predominance of Th2 cells in airways of children with asthma. Exhaled breath condensate analysis may have a useful role in studying allergic inflammation in childhood asthma.

Adolescent↗
PubMed2002

Caspase-catalyzed cleavage and activation of Mst1 correlates with eosinophil but not neutrophil apoptosis.

We have examined the role of caspase-mediated cleavage of the Ste20-like kinases, mammalian sterile 20-like 1 and 2 (Mst1/Mst2), in the mechanism of human eosinophil and neutrophil apoptosis. Initial measurements of kinase activity, using myelin basic protein (MBP) as a substrate in "in-gel" renaturation assays, showed that constitutive eosinophil and neutrophil apoptosis were associated temporally with the activation of a 36-kd MBP kinase (p36 MBPK) and a 34-kd MBP kinase (p34 MBPK), respectively. A constitutively active 63-kd MBP kinase (p63 MBPK) was also detected in freshly prepared eosinophils but not neutrophils, whose activity was transiently augmented during spontaneous apoptosis. Immunoblotting studies demonstrated the expression of Mst1 and Mst2 in eosinophils but not neutrophils whereas immunoprecipitation studies identified the p63 MBPK activity as being Mst1 and Mst2 and showed that the p36 MBPK activity represented the N-terminal catalytic fragment of Mst1. A role for the p36 MBPK in eosinophil cell death was supported by studies showing increased activation upon exposure to the proapoptotic Fas/CD95-activating antibody, CH-11, and attenuation in the presence of the survival-promoting cytokine, interleukin-5. Furthermore, spontaneous and Fas-induced activation of p36 MBPK was inhibited by catalase and the general caspase inhibitor, z-Asp-CH(2)-DCB, at concentrations that suppressed eosinophil apoptosis. These studies therefore implicate a role for caspase- and H(2)O(2)-mediated cleavage of the Mst1 and the subsequent release of the 36-kd catalytic fragment in the mechanism of eosinophil apoptosis. In contrast, neutrophil apoptosis occurs independently of Mst1 and Mst2 but instead is correlated with the activation of an as-yet-unidentified 34-kd MBPK.

Apoptosis↗
PubMed2002

Increased expression of G protein-coupled receptor kinases in cystic fibrosis lung.

A reduction in airway beta-adrenoceptor density has been reported in cystic fibrosis lung but the mechanism underlying this defect remains unclear. In this study, we have investigated whether the decrease in beta2-adrenoceptor associates with altered G protein-coupled receptor kinase (GRK) levels. We assessed GRK activity by rhodopsin phosphorylation, and beta2-adrenoceptor and GRK at the mRNA and protein levels by Northern and Western blotting in peripheral lung samples from normal donors and patients with cystic fibrosis. GRK activity was significantly increased in peripheral cystic fibrosis lung with parallel increases in GRK2/5 mRNAs and protein expression. Functionally, isoproterenol-stimulated adenylyl cyclase activity was also diminished by 65% in cystic fibrosis lung homogenates. These data suggest that the increase in GRK activity may be one of the mechanisms underlying alterations in the coupling between beta2-adrenoceptor and adenylyl cyclase via G-protein and may thus contribute to the downregulation of beta2-adrenoceptor in cystic fibrosis lung.

Adenylyl Cyclases↗
PubMed2002

Faster rise of exhaled breath temperature in asthma: a novel marker of airway inflammation?

In asthma there is increased vascularity of the airway mucosa, altering heat loss in the airways. We hypothesized that as a result of these inflammatory changes, asthmatic patients would have elevated rates of the exhaled air temperature increase (Deltae degrees T). We measured Deltae degrees T in 18 asthmatic subjects (mean age +/- SEM, 38 +/- 8 yr; 9 male, FEV(1) 74 +/- 10%) and 16 normal volunteers (mean age +/- SEM, 33 +/- 3 yr) and compared it with exhaled nitric oxide (NO) as a marker of inflammation. Deltae degrees T was measured during a flow- and pressure-controlled single exhalation with a fast response (1 ms) thermometer. The end-expiratory plateau temperature was similar in asthmatic compared with normal subjects (35.75 +/- 0.6 degrees C and 34.45 +/- 0.8 degrees C, p > 0.05). However, Deltae degrees T was greater in asthmatic subjects (8.17 +/- 0.83 degrees C/s and 4.12 +/- 0.41 degrees C/s, p < 0.01) and correlated with NO (r = 0.65, p = 0.034). Deltae degrees T was increased in normal subjects (from 4.28 +/- 0.8 degrees C/s to 7.60 +/- 0.5 degrees C/s, p < 0.01) but not in asthmatic patients (from 8.28 +/- 0.41 degrees C/s to 8.80 +/- 0.41 degrees C/s, p > 0.05) after the inhalation of albuterol, indicating that Deltae degrees T may reflect bronchial blood flow. Asthmatic subjects have elevated Deltae degrees T. This may represent a novel, noninvasive means of measuring airway blood flow and inflammation in asthma.

Adult↗
PubMed2002

Attenuated production of intracellular IL-10 and IL-12 in monocytes from patients with severe asthma.

Interleukin (IL)-10 and IL-12 production is decreased in peripheral blood mononuclear cells of patients with mild asthma. Using whole blood culture and flow cytometry we examined whether monocyte heterogeneity influenced IL-10 and IL-12 production in subjects with severe asthma. We demonstrated that IL-10 release in LPS-stimulated whole blood culture was decreased in patients with severe persistent asthma compared to those with mild asthma and controls (P = 0.04 and P < 0.001, respectively). In asthmatic patients, the percentage of CD14(+)CD16(+) cells was higher than that from normal subjects (P = 0.04). Severe asthmatics showed significantly less positive staining for IL-10 and IL-12 (P < 0.001 and P = 0.02, respectively) after stimulation in monocytes, compared to mild asthmatics and controls in both CD14(+)CD16(+) and CD14(+)CD16(minus sign) cells. These results suggest that IL-10 synthesis is attenuated in severe persistent asthma compared to mild asthma and that this cannot be explained by the increase in the CD14(+)CD16(+) monocytes in asthma.

Adult↗