PMN Elastase Research Articles

Mesenchymal stem cell attenuates neutrophil-predominant inflammation and acute lung injury in an in vivo rat model of ventilator-induced lung injury.

Background:Subsequent neutrophil (polymorphonuclear neutrophil [PMN])-predominant inflammatory response is a predominant feature of ventilator-induced lung injury (VILI), and mesenchymal stem cell (MSC) can improve mice survival model of endotoxin-induced acute lung injury, reduce lung impairs, and enhance the repair of VILI. However, whether MSC could attenuate PMN-predominant inflammatory in the VILI is still unknown. This study aimed to test whether MSC intervention could attenuate the PMN-predominate inflammatory in the mechanical VILI.Methods:Sprague-Dawley rats were ventilated for 2 hours with large tidal volume (20 mL/kg). MSCs were given before or after ventilation. The inflammatory chemokines and gas exchange were observed and compared dynamically until 4 hours after ventilation, and pulmonary pathological change and activation of PMN were observed and compared 4 hours after ventilation.Results:Mechanical ventilation (MV) caused significant lung injury reflected by increasing in PMN pulmonary sequestration, inflammatory chemokines (tumor necrosis factor-alpha, interleukin-6 and macrophage inflammatory protein 2) in the bronchoalveolar lavage fluid, and injury score of the lung tissue. These changes were accompanied with excessive PMN activation which reflected by increases in PMN elastase activity, production of radical oxygen series. MSC intervention especially pretreatment attenuated subsequent lung injury, systemic inflammation response and PMN pulmonary sequestration and excessive PMN activation initiated by injurious ventilation.Conclusions:MV causes profound lung injury and PMN-predominate inflammatory responses. The protection effect of MSC in the VILI rat model is related to the suppression of the PMN activation.

Effects of Turkish propolis extract on secretion of polymorphonuclear elastase following respiratory burst

Propolis is a natural, resinous, hive product with various bioactive properties. Polymorphonuclear leukocytes (PMNLs) use both oxygen-dependent (respiratory burst) and oxygen-independent mechanisms (releasing proteolytic enzymes such as elastase) to destroy infectious agents. The in vitro effects of dimethyl sulfoxide (DMSO) extract of Turkish propolis on the secretion of PMN elastase from PMNLs following respiratory burst was studied. Phorbol myristate acetate was used to stimulate respiratory burst. The Flow Cytometric CellProbe Oxidative Burst Test was used to determinate if respiratory burst occurred or not and what its severity was after a 4 h incubation with propolis extracts (0 mg/mL, 0.625 mg/mL, 1.25 mg/mL, 2.5 mg/mL, and 5 mg/mL). PMN elastase activity following respiratory burst was determined by Flow Cytometric CellProbe Elastase Test. At the 5 mg/mL concentration, the percentages of fluorescence positivities of DCFH, PMA Oxidative Burst Test were observed as 28 ± 0.316% and 27 ± 0.374% for untreated and PMA-stimulated PMNLs, respectively. At the concentration of 5 mg/mL, percentage of fluorescence positivities of RGES-Elastase Test were observed as 17.5 ± 0.412% and 5.6 ± 0.316% for untreated and PMA-stimulated PMNLs, respectively. It was concluded that DMSO extracts of Turkish propolis may exhibit anti-inflammatory activities by reducing respiratory burst and secreting PMN elastase.

Neutrophil elastase-dependent cleavage compromises the tumor suppressor role of EMILIN1

Proteolysis of the extracellular matrix (ECM) is a key event in tumor growth and progression. The breakdown of ECM can lead to the generation of bioactive fragments that promote cell growth and spread. EMILIN1, a multidomain glycoprotein expressed in several tissues, exerts a crucial regulatory function through the engagement of α4/α9 integrins. Unlike the majority of ECM molecules that elicit a proliferative program, the signals emitting from EMILIN1 engaged by α4/α9β1 integrins are antiproliferative. In this study, aimed to demonstrate if the suppressor role of EMILIN1 was related to its structural integrity, we tested the possibility that EMILIN1 could be specifically cleaved. Among the proteolytic enzymes released in the tumor microenvironment we showed that neutrophil elastase cleaved EMILIN1 in three/four major fragments. The consequence of this proteolytic process was the impairment of its anti-proliferative role. Accordingly, EMILIN1 was digested in sarcomas and ovarian cancers. Sarcoma specimens were infiltrated by neutrophils (PMNs) and stained positively for elastase. The present findings highlight the peculiar activity of PMN elastase in disabling EMILIN1 suppressor function.

Human semen hyperviscosity: prevalence and effects on physical and biochemical semen parameters in subfertile Egyptian men

Background Semen hyperviscosity (SHV) is a condition that can markedly impair the physical and chemical characteristics of seminal fluid, which leads to an adverse impact on sperm function. The aim of this study was to assess the prevalence of SHV in infertile Egyptian men and to evaluate its effects on physical and biochemical semen parameters, and also to identify any correlation between SHV and infections or inflammation of the genital tract. Participants and methods Semen samples were studied for 300 infertile men; of these, 225 men had normal semen viscosity and were excluded from the study. Seventy-five men with SHV were selected and included in this study. In addition, 25 fertile men with completely normal semen parameters who had recently fathered children were included as a control group. All participants underwent seminal analysis and measurement of seminal plasma fructose, ascorbic acid, calcium, and zinc, in addition to a peroxidase test and polymorphonuclear granulocyte elastase (PMN elastase). Results Our study showed that the prevalence of SHV was 25% in infertile Egyptian men. Sperm motility and sperm vitality, in addition to fructose, ascorbic acid, calcium, and zinc levels, were significantly reduced, whereas PMN elastase levels were significantly increased in samples with hyperviscosity (P Conclusion Our results showed that hyperviscosity seems to be the result of infection or inflammation in 75% in our cases and hyperviscosity seems not to be because of a single pathogenic factor, but rather because of several (biochemical, enzymatic, and genetic) factors that act in synergy. These factors should be studied further.

Chemokines, MMP-9 and PMN elastase in spontaneous sputum of sulfur mustard exposed civilians: Sardasht-Iran Cohort Study

Chemokines play an important role in acute and chronic pulmonary diseases. The aim of this study was to evaluate the levels of chemokines, MMP-9, and PMN elastase in spontaneous sputum and serum of patients 20 years after SM exposure. In context of Sardasht-Iran Cohort Study (SICS) 40 male volunteers with a history of SM exposure in June 1987 and complain of excessive sputum were recruited. The volunteers were clinically examined and their history was collected by internists. Sputum and serum levels of IL-8, fractalkine, MCP-1, RANTES, MMP-9, and PMN elastase were measured using ELISA kits (R&D System). Spirometries were performed on all the participants. Sputum level of fractalkine was significantly lower in the hospitalized group (N=16, Median=1.05; IQR=0.41-2.62) than non-hospitalized group (N=18, 4.031; IQR=0.947-8.203) (p=0.042). However, serum levels of fractalkine were higher in the hospitalized group (Mean±SD=2.08±5.09) than in the non-hospitalized (Mean±SD=0.53±0.87) group (T-test, p=0.03). Serum levels of PMN-elastase were also higher in the hospitalized group (Mean±SD; 64,794.43±26,820.08) than in the non-hospitalized group (Mean±SD=44,049.33±17,675.85) (p=0.017). There was no relationship between the cytokines and the studied factors in sputum and the GOLD classification, but the serum levels of fractalkine and MMP-9 were significantly higher in the more severe (grades 3-4) group. There was no significant correlation between sputum and serum levels of measured inflammatory mediators and pulmonary complications in the patients who were exposed to SM 20 years earlier. Pathophysiologic process involved in SM induced pulmonary problems might be different from those in other chronic pulmonary diseases such as COPD and asthma.

Superabsorbent polymer-containing wound dressings have a beneficial effect on wound healing by reducing PMN elastase concentration and inhibiting microbial growth

A comprehensive in vitro approach was used to assess the effects of superabsorbent polymer (SAP) containing wound dressings in treatment of non-healing wounds. A slight negative effect on HaCaT cells was noted in vitro which is most likely due to the Ca(2+) deprivation of the medium by binding to the SAP. It could be shown that SAP wound dressings are able to bind considerable amounts of elastase reducing enzyme activity significantly. Furthermore, SAP's inhibit the formation of free radicals. The SAP-containing wound dressings tested also exhibited a significant to strong antimicrobial activity effectively impeding the growth of gram-negative and gram-positive bacteria as well as yeasts. In conclusion, in vitro data confirm the positive effect of SAP wound dressings observed in vivo and suggest that they should be specifically useful for wound cleansing.

Impact of body mass index on seminal oxidative stress

Male obesity has been linked with a reduction in sperm concentration and motility, an increase in sperm DNA damage and changes in reproductive hormones. Recent large observational studies have linked male obesity with a reduced chance of becoming a father. One of the potential underlying pathological mechanisms behind diminished reproductive performance in obese men is sperm oxidative stress. The primary aim of this study was to determine if sperm oxidative stress was more common in obese/overweight men. A total of 81 men had their body mass index (BMI) correlated with seminal reactive oxygen species (ROS) production (Nitro Blue Tetrazolium assay), sperm DNA damage (TUNEL), markers of semen inflammation (CD45, seminal plasma PMN elastase and neopterin concentration) and routine sperm parameters, together with reproductive hormones. The principal finding from this study was that oxidative stress did increase with an increase in BMI, primarily due to an increase in seminal macrophage activation. However, the magnitude of this increase was small and only of minor clinical significance as there was no associated decline in sperm DNA integrity or sperm motility with increasing ROS production. Increased BMI was also found to be significantly linked with a fall in sperm concentration and serum testosterone, and an increase in serum oestradiol.

α1‐antitrypsin prevents polymorphonuclear leucocyte‐elastase effects on spermatozoa quality

Elevated levels of polymorphonuclear leucocyte (PMN)-derived elastase, which is suggested as marker for inflammations in the male genital tract, correlate well with spermatozoa deterioration. PMN elastase caused a time- and concentration-dependent (up to a elastase concentration of 0.5 microg/mL) externalization of phosphatidylserine and intercalation of propidium iodide on human spermatozoa. There are apparently a limited number of target sites for elastase on spermatozoa surface, because the further enhancement of elastase amount did not fasten alterations in spermatozoa parameters. Analysis of flow cytometry data revealed that most spermatozoa were in a necrotic state after an exposure with elastase for 22 h. Some apoptotic cells were only detected at shorter incubation periods. Seminal plasma prevented in a concentration-dependent manner the PMN elastase-mediated loss of vitality of spermatozoa. We detected by blotting techniques large amounts of alpha(1)-antitrypsin in seminal plasma. This antiproteinase is known to inactivate elastase at inflammatory sites. Increasing concentrations of alpha(1)-antitrypsin prevented gradually spermatozoa deterioration induced by elastase. Thus, alpha(1)-antitrypsin contributes to an efficient protease/antiproteinase balance in seminal plasma. A disturbed balance will promote the development of chronic inflammations which can also be the reason for male infertility problems.

Protease and pro-inflammatory cytokine concentrations are elevated in chronic compared to acute wounds and can be modulated by collagen type I in vitro

Physiological wound repair is a highly regulated, complex process, which leads to formation of new tissue after injury. However, the healing process is not perfect and healing impairments can occur. Delayed healing and formation of chronic wounds has been linked to the excessive production of proteolytic enzymes leading to reduced amounts of growth factors and successive destruction of the extracellular matrix. It has been implied that there is an alteration in the normal control mechanisms regulating the levels of these enzymes. The study presented provides data on the concentration of proteases and cytokines in wound fluid from chronic when compared with acute wounds. Levels of proteases such as PMN elastase, matrix metalloproteinases-2 (MMP-2), and MMP-13 were found to be profoundly elevated in chronic when compared with acute wound fluids. In addition, concentrations of IL-1beta, IL-6, and IL-8 were shown to be significantly higher in chronic than in acute wounds. Furthermore, the ability of a wound dressing, consisting of bovine collagen type I, to bind pro-inflammatory cytokines was investigated. Collagen type I was able to bind significant amounts of the pro-inflammatory cytokines in vitro. Thus, it should be able to establish a more physiological wound milieu in vivo and promote healing.

Semen characteristics and inflammatory mediators in infertile men with different clinical diagnoses

This study was aimed at investigating whether semen characteristics in different clinical diagnoses of infertility are associated with PMN elastase, IL-6, IL-8, IL-1beta and TNFalpha levels detected in seminal plasma. Sixty-eight patients were divided into groups according to their clinical diagnosis: idiopathic infertility (group I), varicocele with infections (group II), varicocele (group III), infections (group IV), controls (group V). Physical examination and scrotal Eco-color Doppler was used to detect the varicocele. Patients with positive bacteriological semen analysis were considered as having an infection of the male reproductive tract. Samples were examined by light microscopy and transmission electron microscopy (TEM). TEM data were quantified with a mathematical formula furnishing a fertility index and the percentage of sperm apoptosis, immaturity and necrosis. PMN elastase/alpha1-PI complex levels were determined by ELISA and IL-6, IL-8, IL-1beta, TNFalpha by Bio-Plex Cytokine assay. Sperm concentration (I-II: p < 0.005; III-IV: p < 0.0001), motility (I-IV: p < 0.0001) and the fertility index (I: p < 0.005; II-IV: p < 0.0001) were significantly lower in the groups vs. controls, whereas sperm pathologies, except for apoptosis, were significantly higher in group I and apoptosis and necrosis were higher in group III. An increase in immaturity (p < 0.005) with a decrease in necrosis (p < 0.005) were observed in group III vs. group IV. Significantly higher levels of inflammatory mediators were detected in groups III and IV vs. controls. Despite a broad relationship among different inflammatory mediators, no correlation was found among them and the semen parameters, including indices from TEM analysis. In conclusion, patients with idiopathic infertility showed altered semen quality and normal levels of inflammatory mediators. Genitourinary infection and varicocele induced an inflammatory effect which could play a detrimental role in spermatogenesis, revealed by a decrease in sperm motility and the fertility index, concomitant with an increase in immaturity mainly in varicocele and necrosis in infection.

No clear clinical benefit of using mini-invasive extracorporeal circulation in coronary artery bypass grafting in low-risk patients

Current research is engaged in innovative technologies of extracorporeal circulation (ECC) systems in an effort to eliminate negative effects. Some studies have shown that, due to the complexity of technical settings of mini-ECC, they invoke a weaker immune response compared to classic ECC. The clinical benefits of using these systems have not been clearly proven yet. A group of 54 patients who were indicated for elective coronary surgery were randomised into two groups - Group A (patients operated on using classic ECC - open modification) and Group B (patients operated on using mini-ECC). The concentrations of IL-6, PMN elastase and MCP-1 in both groups were monitored per- and postoperatively, along with the postoperative clinical course. The groups did not differ in the basic pre- and peroperative characteristics. We recorded a lower priming for mini-ECC (p < 0.001) and significantly reduced hemodilution during ECC. There were no differences in the clinical outcome in either group. Serum concentrations of monitored markers of immune reaction towards ECC showed higher activity during standard ECC. New technologies used in mini-systems have proven to lower activation of the immune system, which can be monitored using kinetics of proinflammatory mediators. In spite of these comparable laboratory results, we did not find differences in short-term clinical results when comparing both these groups of low-risk patients.

Effect of Hemodialysis on Acid Leukocyte-Type Ribonuclease, Alkaline Ribonuclease and Polymorphonuclear Elastase Serum Levels in Patients with End-Stage Renal Disease

Background: Low-molecular-weight proteins (LMWPs) are substances of molecular weights 10–35 kDa, which accumulate in plasma of patients with end-stage renal disease (ESRD) due to the abolishment of plasma renal filtration. LMWPs are considered as a separate group of uremic toxins. Aim: The influence of hemodialysis (HD) on the release of some LMWPs from leukocytes was assessed by comparing levels of serum pancreatic-type alkaline RNase and leukocyte-type acid RNase as well aspolymorphonuclear (PMN) elastase. Methods: The mentioned proteins were assayed in 58 ESRD patients on HD prior and after the dialysis session and compared with the results obtained from 36 healthy subjects. The levels of elastase and acid and alkaline RNase were correlated with HD parameters, residual diuresis, predialysis concentrations of serum creatinine, urea and albumin as well as pre- and postdialysis granulocyte count. Results: Changes in PMN elastase produced by the dialysis session positively correlate with changes in acid RNase levels (r = 0.3650; p = 0.0061), while there is no such correlation for alkaline RNase. There is a negative correlation between pre- and postdialysis differences in levels of acid and alkaline RNases (r = –0.3542; p = 0.008), indicating that HD induces liberation of a factor suppressing alkaline RNase. Levels of acid and alkaline RNase negatively correlate with residual diuresis, indicating its significance in control of LMWP accumulation (r = –0.3970; p = 0.0025; r = –0.2596; p = 0.0533, respectively). Conclusions: Dialysis treatment causes an increase in both acid leukocyte-type and alkaline pancreatic-type RNase activity in plasma. Dialysis-related increases in acid RNase activity correlate with the respective changes in PMN elastase, which suggests that leukocyte activation during dialysis contributes to an increase in plasma LMWPs.

Evaluation of seminal plasma parameters in patients with chronic prostatitis or leukocytospermia.

Though detailed cytological and microbiological diagnostic procedures are routinely carried out in male genital tract infection, the correct diagnosis and localization of inflammation or infection is often difficult. In this prospective study, the relevance of the seminal plasma markers PMN elastase, complement C3, CRP, fructose, PSP 94, PSA, and alpha-glucosidase was investigated in 13 patients with chronic prostatitis, 31 patients with significant leukocytospermia, and 58 patients with non-inflammatory diseases (controls). Statistically relevant results were obtained for PMN elastase when comparing chronic prostatitis with controls, leukocytospermia with controls (P < 0.001) and chronic prostatitis with leukocytospermia (P < 0.05); for complement C3 chronic prostatitis and leukocytospermia vs. controls (P < 0.05) and for fructose/ejaculate leukocytospermia vs. controls (P < 0.05). No statistically relevant differences were found for C-reactive protein, alpha-glucosidase, PSA and prostatic secretory protein (PSP 94). To delimit genital tract inflammation from non-inflammatory patients, cutpoint levels for PMN elastase of 230 ng ml-1 and for C3c of 0.01 g l-1 were suggested. PMN elastase was shown to possess the strongest discriminating power. The assessment of a cutpoint for fructose to indicate seminal vesicle dysfunction is not possible as the significance level is weak (P < 0.05).

Antisperm antibodies and microorganisms in genital secretions--a clinically significant relationship?

In asymptomatic infertility patients, no significant relationship was found between the presence of antisperm antibodies (ASA) in serum and in semen samples (IgG and/or IgA ASA), differentiated with the mixed antiglobulin reaction (MAR), and the microbial colonization of ejaculates covering a broad spectrum of microorganisms. Likewise, there was no significant association of ASA with microbial findings in patients' female partners, who also presented without symptoms of genital tract infection and were screened at the same time. Furthermore, ASA in semen (IgG and IgA) were not significantly related to several potential markers of subclinical male sexual gland infection or inflammation (leukocytes, PMN elastase, albumin, C3c) evaluated in aliquots of the same ejaculates used for immunological testing.

Sperm separation in patients with urogenital infections.

A total of 196 patients attending the Center of Dermatology and Andrology, Giessen, Germany, were examined for fertility problems. Polymorphonuclear elastase, reactive oxygen species (ROS) and the number of round and peroxidase-positive cells were investigated in addition to routine semen analysis. The ejaculates were also analysed before and after sperm separation by means of swim-up or glass wool filtration. In 20 cases of leukocytospermia, sperm concentration, motility, viability, production of reactive oxygen species, and the number of peroxidase-positive cells were evaluated before and after glass wool filtration. The results show that ROS production by viable spermatozoa is highly correlated with the concentration of PMN elastase and the number of both peroxidase-positive and round cells. Multiple regression analysis with motility as dependent parameter showed the number of round cells (n = 91; r = -0.332; P = 0.0030) to be the most important parameter affecting motility, while ROS mainly affects the viability of spermatozoa (n = 69; r = 0.250; P = 0.0107). In the case of leukocytospermia, glass wool filtration significantly reduced the number of peroxidase-positive cells and ROS production (P = 0.0098 and P = 0.0005, respectively). Receiver operating characteristic (ROC) curve analysis for ROS production in the ejaculate using a concentration of 1.000 ng ml-1 PMN elastase as decisive parameter resulted in a cut-off value of 49,489.9 counts 10(-7) viable spermatozoa. The statistical parameters were: Sensitivity: 63.2%, specificity: 100%, positive predictive value: 100%, negative predictive value: 36.1%.

Elevated Serum Concentrations of Polymorphonuclear Neutrophilic Leukocyte Elastase in Systemic Sclerosis: Association with Pulmonary Fibrosis

To determine the serum concentrations and clinical association of polymorphonuclear neutrophilic leukocyte (PMN) elastase in patients with systemic sclerosis (SSc). Serum PMN elastase levels from 21 patients with limited cutaneous SSc (lSSc) and 32 with diffuse cutaneous SSc (dSSc) were examined by ELISA. Serum PMN elastase levels were elevated in patients with SSc, especially dSSc, compared to healthy controls. SSc patients with elevated serum PMN elastase levels had more frequent presence of pulmonary fibrosis, arthritis, contracture of phalanges, and diffuse pigmentation. Anticentromere antibody was detected less frequently in SSc patients with elevated serum PMN elastase levels than in controls. Consistently, serum PMN elastase levels also correlated positively with serum levels of KL-6 and surfactant protein-D, serological markers for pulmonary fibrosis. Serum PMN elastase levels were also associated with levels of serum 8-isoprostane, an oxidative stress marker in SSc. Serum PMN elastase levels were elevated in patients with SSc, and it was more prominent in patients with pulmonary fibrosis, suggesting that serum PMN elastase is a novel serological marker for SSc-related pulmonary fibrosis.

Neutrophil-mediated Activation of Epithelial Protease-Activated Receptors-1 and -2 Regulates Barrier Function and Transepithelial Migration

Neutrophil (PMN) infiltration and associated release of serine proteases contribute to epithelial injury during active phases of mucosal disorders such as inflammatory bowel disease. Previous studies have demonstrated that PMN contact with basolateral surfaces of intestinal epithelial cells in the presence of a chemoattractant results in disruption of barrier function even without transmigration. Similarly, serine protease-mediated activation of epithelial protease-activated receptors (PARs) has been shown to increase permeability. In this study, we assessed whether transmigrating PMNs can regulate barrier function through epithelial PAR activation. Transepithelial resistance (TER) decreased significantly after PMN contact with basolateral surfaces of T84 monolayers or after incubation with PMN elastase and proteinase-3, but not cathepsin G. Inhibition of PMN serine proteases, but not selective inhibition of elastase or cathepsin G, prevented the fall in TER induced by PMN contact and blocked PMN transepithelial migration. Basolateral, but not apical, PAR-1 and -2 activation with selective agonists also decreased TER. PAR-1 and -2 were localized intracellularly and in close proximity to lateral surfaces beneath tight junctions, and expression was increased in colonic mucosa from individuals with Crohn's disease. Combined, but not individual, transfection with small interfering RNAs targeted against epithelial PAR-1 and -2, prevented the fall in TER induced by PMN contact. Furthermore, basolateral PAR-1 and -2 activation induced phosphorylation of myosin L chain kinase and regulatory myosin L chain. Lastly, epithelial PAR-1 and -2 knockdown decreased the rate of PMN transepithelial migration. These results suggest that protease-mediated epithelial PAR-1 and -2 activation, by migrating PMNs, induces signaling events that increase epithelial permeability thereby facilitates PMN transepithelial migration.

Heparin coating of poly(ethylene terephthalate) decreases hydrophobicity, monocyte/leukocyte interaction and tissue interaction

Woven poly(ethylene terephthalate) (PET) is widely used in implantable medical devices. Upon implantation, fibrinogen interacts with the PET and changes conformation, such that the fibrinogen P2 epitope may become exposed. This allows inflammatory cells to interact with the material. In this study we have coated PET with heparin and show that this decreases PET hydrophobicity and the presence of the fibrinogen P2 epitope on the material surface. In addition, we show that heparin-induced reduction of PET hydrophobicity correlates with decreased exposure of the fibrinogen P2 epitope and reduced adhesion of monocytes. Reduction of PET hydrophobicity was furthermore associated with reduced PMN elastase production and decreased interaction between PET and embryonic chicken tissue. We conclude that the heparin coating-induced decrease in PET hydrophobicity is associated with decreased interaction between PET and inflammatory cells. Independent of this interaction, the hydrophobic nature of the heparin coating is related to tissue interaction as demonstrated by a reduction in adhesion, growth and spreading of tissue on PET. The combination of these properties makes heparin coating a candidate for improving biocompatibility of PET.

Airway remodeling and lack of bronchodilator response in steroid-resistant asthma

Steroid-resistant (SR) asthma is characterized by airway inflammation that fails to resolve despite treatment with corticosteroids, raising concerns that resistance to steroid therapy in asthma could lead to airway remodeling. We sought to determine whether SR asthma is accompanied by decreased airflow reversibility and could lead to airway remodeling. Spirometric results were evaluated for 40 asthmatic patients defined as having SR or steroid-sensitive (SS) asthma on the basis of a 1-week course of oral prednisone. Twenty-three asthmatic patients underwent bronchoscopy with collection of bronchoalveolar lavage (BAL) fluid to analyze markers of airway remodeling in BAL fluid and cells. Prednisone significantly improved FEV(1) percent predicted in SS asthma (62.0% +/- 10.9% [mean +/- SD] to 79.4% +/- 11.3%, P < .001) but not in SR asthma (66.9% +/- 10.0% to 65.9% +/- 12.1%). The bronchodilator response was significantly greater in the SS than in the SR group (Delta FEV(1) percent predicted, 33.5% +/- 22.5% vs 15.2% +/- 7.9%; P = .001), regardless of inhaled corticosteroid use. No difference in amounts of matrix metalloproteinase (MMP) 9, PMN elastase, or vascular endothelial growth factor was found in BAL fluid from both groups. Tissue inhibitor of metalloproteinases (TIMP) 1 levels were, however, significantly less in BAL fluid of patients with SR asthma compared with those in patients with SS asthma (921.9 +/- 313.4 vs 2267.0 +/- 456.8 pg/mL, P < .05), resulting in significantly higher MMP-9/TIMP-1 ratios in the BAL fluid of patients with SR asthma (0.24 +/- 0.04 vs 0.11 +/- 0.03, P < .01). Finally, dexamethasone treatment induced TIMP-1 mRNA in BAL fluid cells from patients with SS asthma (P < .01) but not in cells from patients with SR asthma. Bronchodilator reversibility is impaired in SR asthma and is associated with a shift in MMP-9/TIMP-1 ratio caused by inability of steroids to enhance TIMP-1 production, potentially promoting proteolytic activity in airways of patients with SR asthma and contributing to chronic airway remodeling. SR asthma might lead to irreversible airways disease.

Neutrophil Elastase Converts Human Immature Dendritic Cells into Transforming Growth Factor-β1-Secreting Cells and Reduces Allostimulatory Ability

During microbial infection, neutrophils (polymorphonuclear leukocytes; PMNs) activate dendritic cells (DCs). However, early reports illustrated that neutrophil-derived mediators may suppress responses to mitogens. In the present study, we investigated the mechanism used by PMNs to modulate the immunostimulatory ability of DCs. Autologous syngeneic PMNs decreased T-cell proliferation induced by allogeneic DCs. Culture supernatant (CS) derived from PMNs also decreased allostimulation ability of immature DCs and increased the expression of transforming growth factor (TGF)-beta1 on DCs. A TGF-beta1 monoclonal antibody, a CD40 monoclonal antibody, or a serine protease inhibitor reversed the effect of PMN CS on DC allostimulatory ability. Furthermore, elastase reproduced the inhibitory effect of PMN CS on DC allostimulatory ability and the TGF-beta1 production. The role of elastase was confirmed by examining PMN CS from two patients with cyclic neutropenia, a disease due to mutations in the neutrophil elastase gene. These PMN CS samples had reduced elastase activity and were unable to increase DC TGF-beta1 production. Moreover, elastase and PMN CS induced IkappaBalpha degradation in DCs. We conclude that PMNs decrease DC allostimulatory ability via production of elastase leading to a switch of immature DCs into TGF-beta1-secreting cells.