Physiology and pathophysiology of neutral proteinases of human granulocytes

Insulin therapy maintains the performance of PVA-coated PCL grafts in a diabetic rat model

Vascular tissue engineering has shown promising results in "healthy" animal models. However, studies on the efficacy of artificial grafts under "pathological conditions" are limited. Therefore, in this study, we aimed to characterize the performance of polyvinyl alcohol (PVA)-coated poly-ε-caprolactone (PCL) grafts (PVA-PCL grafts) under diabetic conditions. To this end, PCL grafts were produced via electrospinning and coated with the hydrophilic PVA polymer, while a diabetic rat model (DM) was established via streptozotocin injection. Thereafter, the performance of the graft in the infrarenal abdominal aorta of the rats was evaluated in vivo. Thus, we observed that the healthy group showed CD31 positive/αSM positive cells in the graft lumen. Further, the patency rate of the PVA-PCL graft was 100% at 2 weeks (n = 7), while all the DM rats (n = 8) showed occluded grafts. However, the treatment of DM rats with neutral protamine Hagedorn insulin (tDM) significantly improved the patency rate (100%; n = 5). Furthermore, the intimal coverage rate corresponding to the tDM group was comparable to that of the healthy group at 2 weeks (tDM vs. healthy: 16.1% vs. 14.7%, p = 0.931). Therefore, the present study demonstrated that the performance of the PVA-PCL grafts was impaired in DM rats; however, insulin treatment reversed this impairment. These findings highlighted the importance of using a model that more closely resembles the cases that are encountered in clinical practice to achieve a clinically applicable vascular graft with a small diameter.

Proteolytic cleavage of HLA class II by human neutrophil elastase in pneumococcal pneumonia

Bacterial and viral respiratory infections can initiate acute lung injury and acute respiratory distress syndrome. Neutrophils and their granule enzymes, including neutrophil elastase, are key mediators of the pathophysiology of acute respiratory failure. Although intracellular neutrophil elastase functions as a host defensive factor against pathogens, its leakage into airway spaces induces degradation of host connective tissue components. This leakage disrupts host innate immune responses via proteolytic cleavage of Toll-like receptors and cytokines. Here, we investigated whether neutrophils possess proteases that cleave adaptive immune molecules. We found that expression of the human leukocyte antigen (HLA) class II molecule HLA-DP β1 was decreased in THP-1-derived macrophages treated with supernatants from dead neutrophils. This decreased HLA-DP β1 expression was counteracted by treatment with neutrophil elastase inhibitor, suggesting proteolytic cleavage of HLA-DP β1 by neutrophil elastase. SDS-PAGE showed that neutrophil elastase cleaved recombinant HLA-DP α1, -DP β1, -DQ α1, -DQ β1, -DR α, and -DR β1. Neutrophil elastase also cleaved HLA-DP β1 on extracellular vesicles isolated from macrophages without triggering morphological changes. Thus, leakage of neutrophil elastase may disrupt innate immune responses, antigen presentation, and T cell activation. Additionally, inhibition of neutrophil elastase is a potential therapeutic option for treating bacterial and viral pneumonia.

Selenium and selenoproteins in prostanoid metabolism and immunity

Selenium (Se) is an essential trace element that functions in the form of the 21st amino acid, selenocysteine (Sec) in a defined set of proteins. Se deficiency is associated with pathological conditions in humans and animals, where incorporation of Sec into selenoproteins is reduced along with their expression and catalytic activity. Supplementation of Se-deficient population with Se has shown health benefits suggesting the importance of Se in physiology. An interesting paradigm to explain, in part, the health benefits of Se stems from the observations that selenoprotein-dependent modulation of inflammation and efficient resolution of inflammation relies on mechanisms involving a group of bioactive lipid mediators, prostanoids, which orchestrate a concerted action toward maintenance and restoration of homeostatic immune responses. Such an effect involves the interaction of various immune cells with these lipid mediators where cellular redox gatekeeper functions of selenoproteins further aid in not only dampening inflammation, but also initiating an effective and active resolution process. Here we have summarized the current literature on the multifaceted roles of Se/selenoproteins in the regulation of these bioactive lipid mediators and their immunomodulatory effects.

Treatment with DNases rescues hidden neutrophil elastase from aggregated NETs

The release of neutrophil extracellular traps (NETs) is one of the weapons neutrophils have in their armory. NETs consist of extracellular chromatin fibers decorated with a plethora of cytoplasmic and granular proteins, such as the antimicrobial serine protease neutrophil elastase (NE). Because the first description of NETs as beneficial to the host, reports on their double-faced role in health and disease have considerably increased recently. On one hand, NETs reportedly trap and kill bacteria and also participate in the resolution of the acute inflammation associated with infection and with tissue damage. On the other hand, numerous negative aspects of NETs contribute to the etiopathogenesis of autoimmune disorders. Employing soluble and solid fluorescent substrates, we demonstrate the interaction of NE with aggregated NETs (aggNETs), the limitation of its enzymatic activity and the containment of the enzyme from surrounding tissues. These events prevent the spread of inflammation and tissue damage. The detection of DNase 1-dependent elevation of NE activity attests the continuous presence of patrolling neutrophils forming NETs and aggNETs even under conditions physiologic conditions.

Histones and chymotrypsin-like elastases play significant roles in the antimicrobial activity of tongue sole neutrophil extracellular traps

Neutrophil extracellular traps (NETs) are a form of extracellular antimicrobial structure of neutrophils observed in higher and lower vertebrates, the latter including the teleost fish tongue sole Cynoglossus semilaevis. However, the antimicrobial mechanism of fish NETs is unknown. In the present study, we examined the potential contribution of histones and elastases to the antibacterial effect of tongue sole NETs. For this purpose, two histones (CsH2B and CsH4) and two elastases (CsEla1 and CsEla2) of tongue sole were investigated. The histones and elastases possess the conserved domain structures characteristic of that of histones H2B/H4 and trypsin-like serine protease, respectively. Recombinant CsH2B, CsH4, CsEla1, and CsEla2 bound a wide range of Gram-negative and Gram-positive bacteria, and some of the bound bacteria were inhibited in growth by the bound histones/elastases. CsH2B, CsH4, CsEla1, and CsEla2 were all localized in NETs induced by various stimuli including bacterial pathogen. Treatment of NETs with antibodies targeting CsH2B, CsH4, CsEla1, and CsEla2 significantly reduced the antimicrobial effect of NETs. These results indicate that histones and chymotrypsin-like elastases are fundamental components of teleost NETs that play important roles in the antimicrobial activity of NETs.

Inhibition of neutrophil elastase contributes to attenuation of lipopolysaccharide-induced acute lung injury during neutropenia recovery in mice

PURPOSE

Patients in whom neutropenia recovery is complicated by pneumonia have an increased risk of acute lung injury (ALI) and detrimental outcomes. The aim of the present study was to investigate whether inhibition of neutrophil elastase (NE) is effective in lipopolysaccharide (LPS)-induced ALI during neutropenia recovery in a murine model, and whether it upregulates the activation of the MerTK signaling pathway.

METHODS

Cyclophosphamide was given to mice to induce neutropenia. Seven days later, they were administered LPS by intratracheal instillation. Sivelestat, a neutrophil elastase inhibitor, was given by intraperitoneal injection once daily starting on day 0 and continuing until mice were sacrificed on day 5 (preventive group). Alternatively, sivelestat was given after, instead of before, LPS administration on day 2 (therapeutic group).

RESULTS

Sivelestat attenuated the lung edema and histopathological changes associated with LPS-induced lung injury. The accumulation of neutrophils and the concentrations of TNF-α, IL-6, and MPO in bronchoalveolar lavage (BAL) fluids were inhibited effectively by sivelestat. The expression of ICAM-1 and NF-κB p65 was also reduced after sivelestat administration. The protein and gene expression of MerTK tended to increase with sivelestat treatment.

CONCLUSIONS

Sivelestat significantly attenuated LPS-induced ALI during recovery from neutropenia, and this effect was associated with MerTK induction. These findings suggest that NE inhibition could be a promising means of alleviating lung inflammation without increasing susceptibility to infection in ALI/ARDS during neutropenia recovery.

Clinical utility of the neutrophil elastase inhibitor sivelestat for the treatment of acute respiratory distress syndrome

Acute respiratory distress syndrome is a serious condition that can arise following direct or indirect lung injury. It is heterogeneous and has a high mortality rate. Supportive care is the mainstay of treatment and there is no definitive pharmacological treatment as yet. Sivelestat is a neutrophil elastase inhibitor approved in Japan and the Republic of Korea for acute lung injury, including acute respiratory distress syndrome in patients with systemic inflammatory response syndrome. The aim of this review is to examine the clinical utility of sivelestat in different disease states, using data from nonclinical and clinical studies. In nonclinical studies, sivelestat appears to show benefit in acute lung injury without inhibiting the host immune defense in cases of infection. Clinical studies do not yet provide a clear consensus. Phase III and IV Japanese studies have shown improvements in pulmonary function, length of intensive care unit stay, and mechanical ventilation, but a non-Japanese multicenter study did not demonstrate sivelestat to have an effect on ventilator-free days or 28-day all-cause mortality. Evidence of improvement in various parameters, including duration of stay in intensive care, mechanical ventilation, the ratio of partial pressure of arterial oxygen and fraction of inspired oxygen (PaO₂/F_IO₂ ratio) ratio, and lung injury scores, has been shown in patients with sepsis or gastric aspiration, and following the surgical treatment of esophageal cancer. To date, there are no particular concerns regarding adverse events, and the available data do not suggest that sivelestat might worsen infections. One study has analyzed cost-effectiveness, finding that sivelestat may reduce costs compared with standard care. The currently available evidence suggests that sivelestat may show some benefit in the treatment of acute lung injury/acute respiratory distress syndrome, although large, randomized controlled trials are needed in specific pathophysiological conditions to explore these potential benefits.

Effect of hemoperfusion using polymyxin B-immobilized fibers on acute lung injury in a rat sepsis model

Direct hemoperfusion using polymyxin B-immobilized column (PMX-DHP) is recognized as an effective treatment for septic shock. However, whether its efficacy is limited to cardiovascular dysfunction remains unknown. Therefore, we planned to examine the effects of PMX-DHP in an acute lung injury model. [Materials and methods] Rats were assigned to either PMX-DHP group or control group (n= 7 in each). A lung injury was created by the intratracheal instillation of LPS. In PMX-DHP group, an arteriovenous extracorporeal circuit using PMX column was applied for three hours. The same procedure using a dummy column was applied in control group. The lung microcirculation was observed, and adherent leukocytes, RBC velocity, and the arterial PaO2 were calculated. Pathological changes and the wet/dry weight ratio of the lungs were examined. [Results] Adherent leukocytes and platelets to the lung venules were recognized at 3 hours, and their numbers increased over time. Treatment with PMX-DHP significantly suppressed these events and helped maintenance of the blood flow and PaO2 levels. The lung edema and the histologic damages were also suppressed. [Conclusions] PMX-DHP improved the microcirculation by suppressing leukocyte and platelet adhesion. PMX-DHP had beneficial effects in a model for acute lung injury.

Expression and regulation of a disintegrin and metalloproteinase-8 and -17 in development of rat periradicular lesion

INTRODUCTION

A disintegrin and metalloproteinases (ADAMs) are a family of transmembrane proteins that share a common domain structure. However, little is known about the possible involvement of ADAM-8 and ADAM-17 in the development of periradicular lesions. Here we demonstrated the expression of ADAM-8 and ADAM-17 in rat periradicular lesions.

METHODS

We induced experimentally periradicular lesions in rats. The animals were killed at 0, 2, 4, 6, and 8 weeks after pulp exposure. The left molars underwent immunofluorescence analysis for both ADAMs and for neutrophil elastase, and right molars were used for reverse transcription-polymerase chain reaction analysis of ADAM-8 and ADAM-17. The areas of these lesions were measured histometrically, and the numbers of all antigen-positive cells in the periapical portion were counted per unit area.

RESULTS

The area of the periradicular lesions gradually expanded from 0 to 4 weeks, showing a large increase from week 2 to week 4. Both ADAM-8-positive and ADAM-17-positive cells gradually increased in number from 0 to 4 weeks and then decreased from 4 to 8 weeks. There were more ADAM-17-expressing cells than ADAM-8-expressing ones at all experimental periods except at 4 weeks. The highest expression of ADAM-8 mRNA was observed at 4 weeks, and there were significant differences between 0 and 2 weeks and between 4 and 6 weeks. The expression of ADAM-17 mRNA increased from 0 to 4 weeks and subsequently decreased from 4 to 8 weeks, with a significant difference between 4 and 6 weeks.

CONCLUSIONS

Our results suggest that ADAM-8 and ADAM-17 may be related to the development of rat periradicular lesions.

Mechanism for the increased permeability in endothelial monolayers induced by elastase

The aim of this study was to investigate the mechanism for the increase in endothelial permeability induced by human neutrophil elastase (HNE). Pretreatment of bovine pulmonary artery endothelial cells (BPAEC) with HNE(0-30 μg/ml) for 1 h produced a concentration dependent increase in ¹²⁵I-albumin clearance. The effect was reversible and was not due to cytolysis. Pretreatment of BPAEC with sodium tungstate, which depletes xanthine oxidase, or with oxypurinol, did not prevent HNE induced increased permeability. Heparin, which neutralizes the cationic charge of HNE, also had no protective effect. Pretreatment with heat inactivated HNE, which still had positive charge sites, did not result in increased endothelial permeability. Also, ONO-5046, a novel specific inhibitor of HNE, did prevent increased permeability. These results suggest that elastase increases endothelial permeability mainly through its proteolytic effects.

Novel silk fibroin/elastin wound dressings

Silk fibroin (SF) and elastin (EL) scaffolds were successfully produced for the first time for the treatment of burn wounds. The self-assembly properties of SF, together with the excellent chemical and mechanical stability and biocompatibility, were combined with elastin protein to produce scaffolds with the ability to mimic the extracellular matrix (ECM). Porous scaffolds were obtained by lyophilization and were further crosslinked with genipin (GE). Genipin crosslinking induces the conformational transition from random coil to β-sheet of SF chains, yielding scaffolds with smaller pore size and reduced swelling ratios, degradation and release rates. All results indicated that the composition of the scaffolds had a significant effect on their physical properties, and that can easily be tuned to obtain scaffolds suitable for biological applications. Wound healing was assessed through the use of human full-thickness skin equivalents (EpidermFT). Standardized burn wounds were induced by a cautery and the best re-epithelialization and the fastest wound closure was obtained in wounds treated with 50SF scaffolds; these contain the highest amount of elastin after 6 days of healing in comparison with other dressings and controls. The cytocompatibility demonstrated with human skin fibroblasts together with the healing improvement make these SF/EL scaffolds suitable for wound dressing applications.

EFFECTS OF SPECIFIC NEUTROPHIL ELASTASE INHIBITOR, SIVELESTAT SODIUM HYDRATE, IN MURINE MODEL OF SEVERE PNEUMOCOCCAL PNEUMONIA

An excessive amount of neutrophil elastase (NE) released from neutrophils accumulated in the lung can cause tissue damage, despite its importance to host defense against microbial pathogens in severe pneumonia. Therefore, NE inhibitors may reduce tissue damage in lungs with severe pneumonia. In this study, the efficacy of a specific NE inhibitor, sivelestat sodium hydrate (sivelestat), was examined using a murine model of severe pneumonia with Streptococcus pneumoniae. Male mice (CBA/JNCrj, aged 5 weeks) were inoculated intranasally with penicillin-susceptible S. pneumonia (1.0 x 10(5) CFU/mouse). Sivelestat (3 mg/kg) or physiological saline was administered every 12 hours beginning at 12 hours after inoculation. Survival was primarily evaluated. Bronchoalveolar lavage fluid (BALF) and blood were collected at 30 hours after inoculation. Thus, cell counts in BALF and numbers of viable bacteria in blood were determined. Histopathological analysis was also performed. Sivelestat significantly prolonged survival when compared with the control group (P < .05), although all animals died within 4 days. Cell count and histopathological analysis indicated that sivelestat prevented the progression of lung inflammation, such as alveolar neutrophil infiltration and hemorrhage. Furthermore, the number of viable bacteria in blood was significantly lower in the sivelestat group than in the control group (5.69 +/- 0.27 and 6.75 +/- 0.32 log CFU/mL, respectively; mean +/- SEM, P < .01). Sivelestat prolonged survival in this model. A possible explanation for the improved survival is that sivelestat prevents tissue damage by inhibiting NE activity in the lung. Therefore, NE inhibitors may be useful for treating with patients with severe pneumonia.

Transepithelial migration of neutrophils: mechanisms and implications for acute lung injury

The primary function of neutrophils in host defense is to contain and eradicate invading microbial pathogens. This is achieved through a series of swift and highly coordinated responses culminating in ingestion (phagocytosis) and killing of invading microbes. While these tasks are usually performed without injury to host tissues, in pathologic circumstances such as sepsis, potent antimicrobial compounds can be released extracellularly, inducing a spectrum of responses in host cells ranging from activation to injury and death. In the lung, such inflammatory damage is believed to contribute to the pathogenesis of diverse lung diseases, including acute lung injury and the acute respiratory distress syndrome, chronic obstructive lung disease, and cystic fibrosis. In these disorders, epithelial cells are targets of leukocyte-derived antimicrobial products, including proteinases and oxidants. Herein, we review the mechanisms involved in the physiologic process of neutrophil transepithelial migration, including the role of specific adhesion molecules on the leukocyte and epithelial cells. We examine the responses of the epithelial cells to the itinerant leukocytes and their cytotoxic products and the consequences of this for lung injury and repair. This paradigm has important clinical implications because of the potential for selective blockade of these pathways to prevent or attenuate lung injury.

Alpha 1 antitrypsin activity is decreased in human amnion in premature rupture of the fetal membranes

Preterm premature rupture of the membranes (PPROM) has been considered to be closely associated with chorioamnionitis. However, the detailed mechanism is not well understood. Alpha 1 antitrypsin (AAT) was reported to decrease in concentration in amniotic fluid obtained from patients with PPROM. However, the origin of AAT in amniotic fluid has not been clarified. In this study, we assessed the expression and localization of AAT in human amnion, as well as its biological activity in cases with PROM. Human amniotic epithelial (hAE) cells expressed AAT. After stimulation with oncostatin M (OSM), interleukin-6 (IL-6) or tumor necrotic factor alpha (TNF alpha), hAE cells increased the expression of AAT, while the expression of MMP9 was reduced by OSM and induced by TNF alpha. Oxidized AAT (inactivated form) was detected in the amnion with PPROM and TPROM, but not in specimens without PROM. Moreover, AAT activity was decreased in amnions from cases with PROM, regardless of gestational age. Thus, the results showed that AAT in the amnion may function as a protective shield at inflammatory sites, and not as it loses it inhibitory activity in cases with PROM, possibly by oxidation, suggesting that its imbalance contributes to PROM.

Targeting neutrophil elastase in cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a lethal hereditary disease characterised by neutrophil-dominated lung inflammation. These abundant neutrophils produce neutrophil elastase (NE), a destructive serine protease that has direct actions on extracellular matrix proteins and has a role in the host response to inflammation and infection.

OBJECTIVE

This review examines the prospect of developing novel therapies for CF by targeting NE. The authors explore the functions of NE and of naturally-occurring and synthetic NE inhibitors.

METHODS

A literature search was conducted exploring the functions of NE and inhibitors of NE; naturally occurring and synthetic.

CONCLUSIONS

Targeting NE in CF offers therapeutic potential, but optimal inhibitors that can be delivered safely and effectively to the lung are still under development.

Change in the concentration of neutrophil elastase in bronchoalveolar lavage fluid during anesthesia and its inhibition by cholesterol sulfate

Cholesterol sulfate (CS) in the gastrointestinal tract exhibits a mucosal protective activity in mouse ulcer model. To clarify the possible role of CS for protection from the epithelial injury due to neutrophil elastase in the tracheobronchi, the authors determined the concentrations of CS and neutrophil elastase in bronchoalveolar lavage fluid (BALF) from patients under anesthesia, and they examined the inhibitory activity of CS toward neutrophil elastase. The concentrations of CS and neutrophil elastase were determined by thin-layer chromatography and enzyme-linked immunosorbent assaying, respectively, and the effect of CS on the activity of elastase was determined with a chromogenic substrate. CS was found to be present in human lung, tracheal mucosa, and BALF, and a high synthesis of it was detected in the tracheal mucosa, in which cellular cholesterol sulfotransferase was induced depending on the density of tracheal cells. Among lipids in the tracheal mucosa, only CS was demonstrated to exhibit inhibitory activity toward neutrophil elastase, a powerful erosive agent in inflammation. The secretion of elastase from neutrophils into BALF was stimulated during the course of general anesthesia. In contrast, the amount of CS in BALF gradually decreased during anesthesia. On immune-precipitation of neutrophil elastase in BALF, CS was detected in the immune precipitate, which indicates a possible association of CS with neutrophil elastase in BALF.

CONCLUSION

CS, which is a major acidic lipid in the tracheobronchial epithelium, might function as an epithelial inhibitor toward neutrophil elastase secreted in response to several stimuli such as anesthesia.

Sivelestat, a specific neutrophil elastase inhibitor, prevented phorbol myristate acetate-induced acute lung injury in conscious rabbits

The in vivo contribution of neutrophil elastase (NE) in phorbol myristate acetate (PMA)-induced acute lung injury has so far been unclear. This study examined the role of NE in PMA-induced acute lung injury in conscious rabbits, using a specific NE inhibitor, sivelestat sodium hydrate (Sivelestat). A single bolus injection of PMA (40 microg/kg) caused acute lung injury as indicated by an increase in protein concentration and hemorrhage in bronchoalveolar lavage fluid (BALF) 4h after PMA injection. These changes were associated with mild decrease in arterial oxygen pressure and peripheral white blood cell and platelet. When continuously infused starting 1h before and ending 4h post-PMA injection, Sivelestat at 3-30 mg/kg/h that are able to inhibit rabbit NE activity by 60-90%, dose-dependently attenuated both PMA-induced hemorrhagic pneumonitis and the increase in protein concentration in BALF without affecting myeloperoxidase activity in the lung. Histopathological study indicated that sivelestat (30 mg/kg/h) markedly attenuated lung histopathological changes, alveolar hemorrhage and white blood cells migration with evidence of inhibition of NE activity in BALF. These results suggest that NE plays a significant role in PMA-induced acute lung injury and further supports the importance of this enzyme in acute lung injury.

Protective effects of a selective neutrophil elastase inhibitor (sivelestat) on lipopolysaccharide-induced acute dysfunction of the pulmonary microcirculation

OBJECTIVE

The purpose of this study was to evaluate the effect of a neutrophil elastase inhibitor, sivelestat, on lipopolysaccharide-induced acute lung injury through analysis of hemodynamic changes in the pulmonary microcirculation.

DESIGN

Randomized animal study.

SETTING

Medical school laboratory.

SUBJECTS

Twenty-seven Wistar rats (15 rats for microspectroscopic observations, 12 rats for measurements of neutrophil elastase activity and wet-to-dry ratio).

INTERVENTIONS

Thoracosternotomy was performed on male Wistar rats under continuous anesthesia and mechanical ventilation. Rats were divided into three groups (n = 5 each groups) on the basis of the reagent used: lipopolysaccharide group (100 microg/kg lipopolysaccharide intravenously), sivelestat group (10 mg/kg sivelestat; 100 microg/kg lipopolysaccharide intravenously), and control group (saline only, intravenously).

MEASUREMENTS AND MAIN RESULTS

We measured morphologic changes and hemodynamic variables, including tissue blood flow, erythrocyte velocity, erythrocyte count, thickness of interalveolar septa, and leukocyte adhesion in the pulmonary microcirculation, with a video-rate (33 msec/frame) dual-spot microspectroscopy system (DSMSS) and a laser-Doppler flowmeter. Blood-free wet-to-dry ratio and neutrophil elastase activity in bronchoalveolar lavage fluid, serum, and supernatant of lung homogenate were measured in another set of experiments (n = 4 for each group). Sixty minutes after lipopolysaccharide administration, severe thickening of the interalveolar septa was observed in the lipopolysaccharide but not the sivelestat group. In the lipopolysaccharide group, DSMSS measurements of erythrocyte velocity and hemoglobin oxygenation in single capillaries were decreased significantly (vs. control p < .05, vs. sivelestat p < .01), whereas tissue blood flow and erythrocyte velocity measurements from laser-Doppler flowmeter were increased significantly (vs. control p < .05, vs. sivelestat p < .01). The number of adherent leukocytes was increased significantly in the lipopolysaccharide group at 30, 45, and 60 mins after lipopolysaccharide administration (vs. control p < .01, vs. sivelestat p < .05). The number of adherent leukocytes did not increase in the sivelestat group. The wet-to-dry ratio was significantly higher in the lipopolysaccharide group than in control (p < .05) and sivelestat (p < .05) groups. Neutrophil elastase activities in the bronchoalveolar lavage fluid, serum, and lung tissue were all significantly lower in the sivelestat group than in the lipopolysaccharide group (p < .05).

CONCLUSIONS

Lipopolysaccharide induces leukocyte adhesion in the pulmonary microcirculation, resulting in decreased tissue hemoglobin oxygen and alveolar and interstitial edema. The selective neutrophil elastase inhibitor sivelestat reduces neutrophil elastase activity and attenuates acute changes in the pulmonary microcirculation.

Proteinase-activated receptor-1 mediates elastase-induced apoptosis of human lung epithelial cells

Apoptosis of distal lung epithelial cells plays a pivotal role in the pathogenesis of acute lung injury. In this context, proteinases, either circulating or leukocyte-derived, may contribute to epithelial apoptosis and lung injury. We hypothesized that apoptosis of lung epithelial cells induced by leukocyte elastase is mediated via the proteinase activated receptor (PAR)-1. Leukocyte elastase, thrombin, and PAR-1-activating peptide, but not the control peptide, induced apoptosis in human airway and alveolar epithelial cells as assessed by increases in cytoplasmic histone-associated DNA fragments and TUNEL staining. These effects were largely prevented by a specific PAR-1 antagonist and by short interfering RNA directed against PAR-1. To ascertain the mechanism of epithelial apoptosis, we determined that PAR-1AP, thrombin, and leukocyte elastase dissipated mitochondrial membrane potential, induced translocation of cytochrome c to the cytosol, enhanced cleavage of caspase-9 and caspase-3, and led to JNK activation and Akt inhibition. In concert, these observations provide strong evidence that leukocyte elastase mediates apoptosis of human lung epithelial cells through PAR-1-dependent modulation of the intrinsic apoptotic pathway via alterations in mitochondrial permeability and by modulation of JNK and Akt.

Effect of Ulinastatin, a human urinary trypsin inhibitor, on the oleic acid-induced acute lung injury in rats via the inhibition of activated leukocytes

BACKGROUND

The acute respiratory distress syndrome (ARDS) is often caused by fat tissue embolism. One of the most common animal models of ARDS is produced by direct administration of oleic acid (OA). Activated leukocytes are critically involved in the pathological mechanism in this model. Human urinary trypsin inhibitor (UTI) is known to inhibit production of tumor necrosis factor (TNF)-alpha, which potently stimulates leukocyte activation. The purpose of this study was to clarify whether UTI improves OA-induced lung injury in rats by inhibiting activated leukocytes via TNF-alpha production.

MATERIALS AND METHODS

Rats were subjected to a single intravenous administration of OA into the pedicle vein. Acute lung injury was evaluated by arterial blood gases and histological changes in lungs. Pulmonary vascular permeability, accumulation of neutrophils, and the levels of TNF-alpha in lung tissues were also examined. Rats were divided into four experimental groups: a sham operated, OA, OA + UTI, and OA + nitrogen mustard (NM)-induced leukocytopenia group. UTI was intravenously administered 30 min before OA administration. Leukocytopenia was induced by the administration of NM.

RESULTS

UTI significantly improved the OA-induced histological changes for 4 h after OA administration. The OA-induced reduction of PaO2, the increase of pulmonary vascular permeability, and the levels of MPO activity and TNF-alpha in lung tissues were significantly improved in rats administrated UTI. The effects in the leukocytopenia group were similar to those in the UTI-administered group.

CONCLUSION

Leukocytes play a critical role in the development of OA-induced lung injury. It was suggested that UTI contributed to the reduction in the OA-induced lung injury by inhibiting TNF-alpha and thereby suppressing leukocyte.

Thromboxane A2 Up-Regulates Neutrophil Elastase Release in Syrian Hamsters With Trinitrobenzene Sulfonic Acid-Induced Colitis

Neutrophil elastase (NE) is a factor that aggravates colitis. We investigated the influence of thromboxane A2 (TXA2) and leukotriene B4 (LTB4) on NE release in Syrian hamsters with trinitrobenzene sulfonic acid-induced colitis. Colonic specimens with colitis were incubated with U-46619 (a TXA2 analogue) or LTB4 in vitro and NE release was examined. As a result, U-46619 increased NE release, while LTB4 had no effect. The NE release induced by U-46619 was inhibited by a TP-receptor antagonist. To demonstrate that TXA2 caused NE release in vivo as well, while LTB4 did not, colitis animals were treated with nordihydroguaiaretic acid (NDGA), a dual inhibitor of cyclooxygenase/lipoxygenase; and colonic luminal TXB(A)2 and LTB4 levels and NE activity were determined. The TXB(A)2 level was significantly correlated with NE activity, while no correlation was found between LTB4 and NE activity. An inhibitory effect of NDGA on the ulcer area was also observed, and NE activity was significantly correlated with the ulcer area. The suppression of TXA2 production by NDGA may result in the inhibition of NE release so that colonic tissue damage becomes less severe. Regulation of NE release is a new biological action of TXA2 that has not been reported before.

Effects of Granulocyte Colony-Stimulating Factor (G-CSF) and Neutrophil Elastase Inhibitor (ONO-5046) on Acid-Induced Lung Injury in Rats

It has been suggested that neutrophils play an important role in acid-aspirated lung injury. We examined the effects of the high dose of granulocyte-colony stimulating factor (G-CSF), which is capable of increasing peripheral neutrophils, and a specific neutrophil elastase inhibitor (ONO-5046) on acid lung injury in rats. Animals were anesthetized and normal saline (NS, 2 mL kg(-1)) or hydrochloric acid (HCl, 0.1 N 2 mL kg(-1)) was then instilled into trachea. Thirty minutes before HCl instillation, G-CSF (150 microg kg(-1)) was injected subcutaneously or ONO-5046 (10 mg kg(-1) h(-1)) was infused continuously into the right jugular vein. Animals were ventilated during the experiments. Five hours after HCl or NS instillation, bronchoalveolar lavage fluid (BALF) and lung tissue samples were obtained. Total nuclear cell count, absorbance, albumin, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant (CINC), neutrophil elastase in BALF, wet-to-dry (W/D) ratio were measured. HCl aspiration markedly increased these values in BALF and W/D ratio. Both ONO-5046 and G-CSF attenuated the parameters increased by acid-induced lung injury in rats. The data suggests that neutrophils play an important role in acid-induced lung injury. However, high-dose G-CSF does not exacerbate acid-aspirated lung injury in rats, although this agent causes an increase in peripheral neutrophils.

Effects of low molecular weight chondroitin sulfate on type II collagen-induced arthritis in DBA/1J mice

In order to evaluate the improvement in the treatment of chronic arthritis, we investigated chondroitin sulfate depolymerization product (low molecular weight chondroitin sulfate, LMWCS) and intact chondroitin sulfate (CS) in vitro and in vivo. LMWCS was prepared by a chemical depolymerization process induced by hydrogen peroxide in the presence of copper salts. LMWCS (300 mg/kg) and CS (1200 mg/kg) were orally administered to DBA/1J mice once daily for 14 d prior to initial immunization with type II collagen. Their elastase activities and the production of cytokines in sera were examined on type II collagen-induced arthritis in DBA/1J mice. We also compared the paracellular transport of LMWCS and CS across Caco-2 cell monolayers and examined the inhibitory effects on elastase activities. LMWCS inhibited elastase activity slightly, but CS did not show inhibition. Hind paw edema was significantly decreased by LMWCS treatment. Levels of anti-type II collagen antibody and tumor necrosis factor-alpha (TNF-alpha) in sera were also reduced by LMWCS treatment but not in case of CS, although no significant difference was observed between LMWCS and CS on interleukin-6 (IL-6) induction. The LMWCS preparation showed preventive effects on the type II collagen-induced arthritis in DBA/1J mice and better permeability through Caco-2 cells.

Colonic ulceration and increase of neutrophil elastase activity in the acetic acid-induced colitis model in Syrian hamsters

A novel colitis model using Syrian hamsters was developed. Colitis was induced by intracolonic administration of 1% acetic acid, and the ulcer area, tissue myeloperoxidase (MPO) activity, and luminal neutrophil elastase (NE) activity of the colon were determined at 1, 3, 8, 24 and 48 hr after colitis induction. The histopathological changes of the colon were also examined in this model. An increase of tissue MPO activity and NE activity was evident at 3 hr after induction of colitis, peaked at 24 hr, and decreased subsequently. The increase of luminal NE activity was well correlated with the colonic ulcer area. In histopathological examination, ulceration, erosion, crypt abscesses, neutrophil infiltration, hemorrhage, and edema were seen. The effects of prednisolone were examined to evaluate the adequacy of our colitis model. Syrian hamsters were treated orally with prednisolone at 18 and 1 hr before and at 6 hr after induction of colitis, and the ulcer area, tissue MPO activity, and luminal NE activity were evaluated at 24 hr after colitis induction. Prednisolone therapy had little effect on the tissue MPO activity. However, the NE activity of the prednisolone-treated group was significantly decreased. In addition, although prednisolone did not significantly decrease the ulcer area, a tendency toward decrease was noted. We conclude that this new model of experimental colitis in Syrian hamsters is useful for investigating the pathophysiology of colitis, especially useful for studying the relationship between colitis and NE activity.

Elastase inhibition reduced death associated with acid aspiration-induced lung injury in hamsters

This study examined whether the specific inhibition of neutrophil elastase by sivelestat sodium hydrate (sivelestat) reduced deaths associated with severe acute lung injury after hydrochloric acid (HCl) aspiration in hamsters. Animals that received a single intratracheal instillation of HCl (0.2 N, 200 microL) time-dependently died by occlusion of their trachea with inflammatory exudate. In a time course study, these animals developed severe lung injury, peaking 12 to 24 h after HCl instillation, as indicated by hemorrhage and a massive increase in the protein concentration of bronchoalveolar lavage fluid. These changes were closely correlated with neutrophil elastase activity in bronchoalveolar lavage fluid. Sivelestat (0.01, 0.1 and 1 mg/kg/h), when intravenously infused during the first 48 h post-HCl instillation, dose-dependently reduced death in HCl-instilled hamsters. In a separate experiment, analysis of bronchoalveolar lavage fluid parameters and partial pressure of arterial oxygen (PaO(2)) 8 h post-HCl instillation showed that sivelestat at 1 mg/kg/h, i.v. significantly improved both bronchoalveolar lavage fluid parameters and PaO(2) levels with evidence of the inhibition of neutrophil elastase activity in bronchoalveolar lavage fluid. These results suggest that neutrophil elastase plays a significant role in this type of severe acute lung injury that leads to death by respiratory failure.

Effects of the Neutrophil Elastase Inhibitor (ONO-6818) on Acetic Acid Induced Colitis in Syrian Hamsters

Neutrophil elastase (NE) released from neutrophils during inflammation is related to tissue disturbance and organ failure. We investigated the effects of an orally active NE inhibitor, ONO-6818, on acetic acid induced colitis in Syrian hamsters. The ulcer area, hemoglobin level in the colonic lumen, NE activity, and tissue myeloperoxidase (MPO) activity in the colitis control animals were significantly increased compared to the normal control ones. Either oral or subcutaneous treatment with ONO-6818 had significant inhibitory effects on the ulcer area, hemoglobin level and NE activity in the colonic lumen, but ONO-6818 did not have a significant inhibitory effect on tissue MPO activity. We conclude that NE is closely related to the development of inflammation in acetic acid-induced colitis in Syrian hamsters and that the condition is improved by the inhibition of NE.

ONO-6818, a novel, potent neutrophil elastase inhibitor, reduces inflammatory mediators during simulated extracorporeal circulation

BACKGROUND

Among the serine proteases, neutrophil elastase is a powerful cytotoxic enzyme and plays a pivotal role in the inflammatory response associated with cardiopulmonary bypass. This study assesses the effects of the specific inhibition of neutrophil elastase by a novel, potent, low-molecular-weight neutrophil elastase inhibitor, ONO-6818. We hypothesized that ONO-6818 reduces inflammatory mediators and modulates adhesion molecules and the deformability of neutrophils during simulated extracorporeal circulation.

METHODS

Simulated extracorporeal circulation was established by recirculating fresh heparinized (3.75 U/mL) human blood for 120 minutes in a membrane oxygenator and a roller pump with and without 1.0 micromol/L of ONO-6818 (n = 9 for control group, n = 7 for ONO-6818 group). The neutrophil adhesion molecules, CD11b and L-selectin, and the cytoplasmic F-actin of neutrophils were measured by flow cytometry. Neutrophil deformability was evaluated using simulated silicon microcapillaries. Neutrophil elastase, interleukin 8, and C5b-9 were measured using enzyme immunoassay.

RESULTS

Neutrophil elastase levels were significantly lower in the ONO-6818 group. ONO-6818 significantly reduced interleukin 8 and C5b-9 production. ONO-6818 did not modulate changes of CD11b and L-selectin during recirculation. Cytoplasmic F-actin content and changes of neutrophil deformability did not significantly differ between the groups.

CONCLUSIONS

Inhibition of neutrophil elastase activity with ONO-6818 reduces further interleukin 8 production and the formation of the complement membrane attack complex, and this results in a reduction of neutrophil elastase levels during simulated extracorporeal circulation. This study suggests that specific neutrophil elastase inhibition with ONO-6818 is a feasible therapeutic option to attenuate the exaggerated inflammatory response associated with cardiopulmonary bypass.

Detection of collagen type II and proteoglycans in the synovial fluids of patients diagnosed with non-infectious knee joint synovitis indicates early damage to the articular cartilage matrix

OBJECTIVE

We have sought to determine if markers of proteoglycans and collagen type II (CII) degradation can be detected at an early stage following acute knee injury in the synovial fluid (SF) from a group of patients diagnosed with non-infectious knee joint synovitis (KJS). CII, proteoglycans and elastase activity in the SF from patients with KJS were compared to SF from patients with two chronic arthritis conditions: osteoarthritis (OA) and rheumatoid arthritis (RA) as well as normal SF controls.

METHODS

CII peptides were measured by sandwich ELISA using two monoclonal antibodies: 8:6:D8, a CII-specific antibody, and 14:7:D8 which binds to an amino acid sequence on CII as well as collagens type I, III and V. Epitope 9A4, a neo-epitope resulting from collagenase digestion of CI, CII, and CIII was measured by inhibition ELISA. Proteoglycans measurement included total sulfated glycosaminoglycans (sGAG) by dye-binding assay and 5-D-4 epitope, a keratan sulfate epitope, by inhibition ELISA. Elastase activity was measured colorimetircally using N-succinyl trialanine p-nitroanilide (SANA) substrate.

RESULTS

The quantified CII peptide concentrations by sandwich and inhibition ELISA were significantly higher in SF from patients with KJS (P<0.05) compared to SF from patients with OA, RA and normal aspirates. 5-D-4 and sGAG concentrations were significantly lower (P<0.05) in SF from patients with KJS compared to SF from patients with OA and RA. Elastase activity in SF from patients with KJS and RA were significantly higher (P<0.05) than SF from patients with OA. A significant correlation exists between elastase activity and 9A4 epitope concentration in SF from patients with KJS.

CONCLUSION

The elevated CII peptides concentrations in KJS SF compared to normal and OA aspirates indicate early signs of cartilage network damage. The low proteoglycans concentrations in SF from patients with KJS may indicate that injury is limited to the superficial zone of cartilage in the patient population studied. The high elastase activity in SF from patients with KJS and RA are linked to the high CII peptides concentration. The elastase activity in the SF from patients with KJS is due to the action of neutrophil elastase (NE) and collagenases, where both contribute to the destruction of the articular cartilage.

Proteases and lung injury

OBJECTIVE

Acute respiratory distress syndrome (ARDS) represents an inflammatory process that is initiated by diverse systemic and/or pulmonary insults, resulting in a clinical syndrome of severe respiratory distress and refractory hypoxemia. Neutrophils and their cytotoxic products, including oxidants and proteases, such as elastase, have been implicated as playing a key role in the pathophysiology of ARDS. This article reviews some of the physiologic actions of proteases, specifically elastase, the evidence for neutrophil elastase involvement in ARDS, and the potential therapeutic use of neutrophil elastase inhibitors in lung injury.

DATA SOURCE

A review of published literature (original articles and reviews) in English from 1965 to 2002.

CONCLUSION

Although the data support a key role for neutrophil elastase in the pathogenesis of ARDS, further study is needed to fully define the actions of neutrophil elastase, and how these actions affect host functions, before we can exploit this knowledge for therapeutic benefit.

The role of neutrophil elastase in acute lung injury

Beside its physiological function as a powerful host defense, neutrophil elastase is also known as one of the most destructive enzymes in the body. Current notion holds that neutrophil elastase is able to escape from regulation by multiple protease inhibitors at inflammatory sites. Once unregulated, this enzyme disturbs the function of the lung permeability barrier and induces the release of pro-inflammatory cytokines. These actions then cause symptoms that are typical in the pathophysiology of acute lung injury. In this article, we review recent progress in the understanding of the physiological activity of neutrophil elastase and its role in acute lung injury. Evidence in this review that supports the involvement of neutrophil elastase in the pathophysiology of acute lung injury includes: (1) neutrophil elastase levels are increased in both clinical and animal models of acute lung injury; (2) topical or systemic administration of neutrophil elastase produces typical symptoms of acute lung injury both in vitro and in vivo; and (3) inhibition of increased neutrophil elastase activity reduces symptoms of acute lung injury in animal models. A greater understanding of the role of this enzyme in the pathophysiology of acute lung injury will lead to better treatments for this complicated disease.

Release of a new vascular permeability enhancing peptide from kininogens by human neutrophil elastase

Stimulated neutrophils produced vascular permeability enhancing (VPE) activity in the presence of high molecular weight kininogen (HMWK), which was inhibited mainly by a neutrophil elastase (NE) inhibitor or a bradykinin (BK) B(2)-receptor antagonist. NE (>3 nM) generated VPE activity from kininogens at normal plasma concentrations with the smaller protein being several fold more responsive than the larger protein, through releasing a new VPE peptide (E-kinin), SLMKRPPGFSPFRSSRI. Synthetic E-kinin, SLMKRPPGFSPFRSS and SLMKRPPGFSPFR had VPE and blood pressure lowering activities, which were comparable to the activities of BK and completely inhibited by B(2)-receptor antagonists. Interestingly, E-kinin and SLMKRPPGFSPFRSS did not induce smooth muscle contraction. These results suggest that E-kinin formed in vivo may be processed at the carboxy-terminus to give a peptide that can bind to the B(2)-receptor. The molecular mechanism for neutrophil-associated VPE may be explained by excision of E-kinin from kininogens by NE, followed by further processing of the peptide.

Fatal pulmonary arterial thrombosis associated with chlorine gas poisoning

We present a patient with accidental chlorine gas poisoning who died from pulmonary thrombosis due to a marked increase in hemostatic factors such as von Willebrand factor after recovering from the acute poisoning.

Inhibition of neutrophil elastase activity attenuates complement-mediated lung injury in the hamster

The role of neutrophil elastase in complement-mediated lung injury was examined in hamsters using a specific neutrophil elastase inhibitor, sodium N-[2-[4-(2,2 dimethylpropionyloxy)phenylsulfonylamino]benzoyl]aminoacetate tetrahydrate (sivelestat). Intravenous injection with cobra venom factor (CVF) into hamsters transiently increased plasma neutrophil elastase activity by about 10-fold. This increase was followed by a sustained increase in lung vascular [125I]bovine serum albumin permeability peaking 30 min after CVF injection. The increase in lung vascular permeability was associated with neutrophil accumulation in lung tissue and an increase in protein concentration in the bronchoalveolar lavage fluid. Inhibition of the elevated plasma neutrophil elastase activity (36.5%, 66.9% and 104.3%) by continuous i.v. infusion with sivelestat (0.1, 0.3 and 1 mg/kg/h), dose-dependently attenuated the increase in lung vascular permeability 30 min after CVF injection. Furthermore, sivelestat at 1 mg/kg/h almost totally prevented the increase in protein concentration in the bronchoalveolar lavage fluid without affecting lung neutrophil accumulation. These results suggest that neutrophil elastase is an important mediator in complement-mediated acute lung injury.

Delayed neutrophil elastase inhibition prevents subsequent progression of acute lung injury induced by endotoxin inhalation in hamsters

To define the role of neutrophil elastase (NE) in the progression of acute lung injury (ALI), we examined the effects of post-treatment with a specific NE inhibitor, sivelestat sodium hydrate (sivelestat), on ALI induced by endotoxin (ET) inhalation in hamsters. Inhalation of ET (300 microg/ml, 30 min) in conscious hamsters increased inflammatory cell count, protein concentration, and hemorrhage in bronchoalveolar lavage fluid (BALF) that peaked 24 h after ET inhalation. These changes were significant 2 h after ET inhalation and paralleled the increase in NE activity in BALF. When intravenously infused from 2 to 24 h post-ET inhalation, sivelestat (0.03 to 3 mg/kg/h) dose-dependently attenuated changes in these BALF parameters at 24 h post-ET inhalation in a manner dependent on the inhibition of NE activity in BALF. Histopathological analysis also indicated that sivelestat prevented the progression of lung inflammation such as alveolar neutrophil infiltration and hemorrhage. In contrast, dexamethasone (3 mg/kg, intravenously) was not effective in this model when administered 2 h after ET inhalation, although it was highly effective when applied before ET. We conclude that delayed inhibition of NE activity with sivelestat prevents subsequent progression of ALI in hamsters after ET inhalation. Thus NE may play an important role in the progression of ALI.

Surgical stress and the development of complications in relation to polymorphonuclear leukocyte elastase (PMNE) levels

This study was conducted to examine the effects of surgical stress on changes in polymorphonuclear leukocyte elastase (PMNE) levels, and to evaluate the relationship of these changes to the development of postoperative complication. A total of 69 patients who underwent alimentary surgery were subsequently divided into three groups: a complicated group, comprised of 25 patients; an uncomplicated group with a high blood loss (H) of more than 1000 ml, comprised of 18 patients; and an uncomplicated group with a low blood loss (L) of less than 1000 ml, comprised of 26 patients. The changes in the levels of PMNE, fibronectin (FN), and antithrombin III (AT III) were compared among these three groups. In the uncomplicated H and L groups the PMNE levels rose significantly on postoperative day (POD) 1. On POD 3, high levels of PMNE were still evident in the uncomplicated H group, but a decline was observed in the uncomplicated L group. From POD 7 onwards the levels decreased to the preoperative values in both uncomplicated groups; however, the complicated group continued to show high levels even on POD 14. Significantly decreased FN levels were observed for the first 3 PODs in each group. The uncomplicated H and L groups regained their preoperative levels on PODs 7 and 14, respectively, but no recovery was found in the complicated group. The AT III levels showed similar changes to the FN levels in all groups. These findings indicate that monitoring the PMNE levels could be a useful index for the early detection of postoperative complications following alimentary surgery.

Release of neutrophil elastase and its role in tissue injury in acute inflammation: effect of the elastase inhibitor, FR134043

Neutrophil elastase degrades extracellular matrix components and is involved in tissue destruction in several inflammatory states. We examined the inhibition of the elastase activity derived from activated neutrophils in vitro and in vivo by FR134043, disodium-(Z,1S,15S,18S,24S,27R,29S,34S,37R)-29-b enzyl-21-ethylidene-27-hydroxy-15-isobutyrylamino-34-isopropyl-31, 37-dimethyl-10,16,19,22,30,32,35,38-octaoxo-36-oxa-9,11,17,20,23,2 8,31,33-octaazatetracyclo[16.13.6.1(24,28).0(3,8)]octatriconta+ ++-3,5,7-trien-5,6-diyl disulfate, an elastase inhibitor with broad specificity, and elucidated the role of neutrophil elastase in pathogenesis of acute inflammation. In a culture of human neutrophils, phorbol myristate acetate (PMA) and calcium ionophore increased elastase activity in the supernatants, which was amplified by co-existing mononuclear leukocytes. Formyl-Met-Leu-Phe stimulated elastase release in the presence of, not without, mononuclear leukocytes. Intratracheal injection of lipopolysaccharide elevated the elastase activity in bronchoalveolar lavage fluid of rats. These elastase activities were significantly inhibited by FR134043. Intratracheal treatment with FR134043 in rats also inhibited the enzyme induced by lipopolysaccharide, though the maximum inhibition was 52%. Ear edema elicited by topical application of PMA in mice was significantly suppressed by pretreatment with FR134043 (38% inhibition at 1 mg/ear). In carrageenan-induced joint injury in rats, plasma extravasation into the synovial cavity was partially and significantly inhibited by FR134043 at 1 mg/knee, while an elastase-specific inhibitor showed no effect. These results suggest that neutrophil elastase is partially involved in tissue damage in acute inflammation provoked by irritants, but not in carrageenan-induced hyperpermeability.

Antithrombin III in patients with severe sepsis. A randomized, placebo-controlled, double-blind multicenter trial plus a meta-analysis on all randomized, placebo-controlled, double-blind trials with antithrombin III in severe sepsis

OBJECTIVES

To evaluate the safety and potential efficacy of antithrombin III (AT III) in reducing mortality in patients with severe sepsis.

DESIGN

Prospective, randomized, placebo-controlled, double-blind, phase II, multicenter, multinational clinical trial.

SETTING

Seven academic medical center intensive care units (ICU) in Belgium, Denmark, the Netherlands, Norway and Sweden.

PATIENTS

42 patients with severe sepsis who received standard supportive care and antimicrobial therapy, in addition to the administration of AT III or placebo.

INTERVENTIONS

Patients received either an intravenous loading dose of 3000 IU AT III followed by a maintenance dose of 1500 IU every 12 h for 5 days or equivalent amounts of placebo.

MEASUREMENTS AND RESULTS

All patients were evaluated for safety and for 30-day all-cause mortality.

CONCLUSIONS

The administration of AT III was safe and well-tolerated. It was followed by a 39 % reduction in 30-day all-cause mortality (NS). The reduction in mortality was accompanied by a considerably shorter stay in the ICU. Patients treated with AT III exhibited a better performance in overall severity of illness and organ failure scores (Acute Physiology and Chronic Health Evaluation II, multiple organ failure, organ system failure), which was noticeable soon after initiation of treatment. Patients treated with AT III demonstrated a better resolution of pre-existing organ failures and a lower incidence of new organ failures during the observation period. A meta-analysis comprising this and two other double-blind, placebo-controlled trials with AT III with a total of 122 patients suffering from severe sepsis confirms the positive trend. The results of the meta-analysis demonstrate a 22.9 % reduction in 30-day all-cause mortality in patients treated with AT III. Although still too small to be confirmative, the meta-analysis clearly points to the fact that a sufficiently powered phase III trial is warranted to prove whether AT III has a beneficial role in the treatment of severe sepsis.

Biochemical and pharmacological characterization of FR134043, a novel elastase inhibitor

FR134043, disodium(Z,1S,15S,8S,24S,27R,29S,34S,37R)-29-ben zyl-21-ethylidene-27-hydroxy-15-isobutyrylamino-34-isopropyl-31,37 -dimethyl-10,16,19,22,30,32,35,38-octaoxo-36-oxa-9,11,17,20,23,28, 31,33-octaazatetracyclo[16.13.6.1(24),(28).0(3),(8)]octatricont a-3,5,7-trien-5,6-diyl disulfate, is a water-soluble inhibitor of human neutrophil elastase with a molecular mass of 1166.15 Da. FR134043 demonstrated a characteristic competitive inhibition of human neutrophil elastase with a Ki of 8 nM. In studies using synthetic substrates, FR134043 inhibited both neutrophil elastase activity and porcine pancreatic elastase activity with IC50 values of 35 nM and 49 nM respectively. FR134043 also inhibited hydrolysis of bovine neck ligament elastin by human neutrophil elastase with an IC50 value of 210 nM. In in vivo experiments, FR134043 protected animals against human neutrophil elastase (50 microg/animal)-induced lung hemorrhage in hamsters with an ED50 value of 3.1 microg/animal for intratracheal administration and 5.0 mg/kg for intravenous administration. Subcutaneous treatment with FR134043 significantly suppressed human neutrophil elastase (20 microg/paw)-induced paw edema in mice with an ED50 value of 3.3 mg/kg when evaluated 4 h after elastase injection. The potency of FR134043 given intratracheally to protect against porcine pancreatic elastase (100 microg/animal)-induced emphysema in hamsters was relatively low (Quasi-static lung compliance; ED50 = 1590 microg/animal) compared to that in acute animal models. FR134043 (10 mg/kg per h i.v. infusion) significantly improved lipopolysaccharide (0.25 mg/kg per h i.v. infusion)-induced thrombocytopenia and some coagulation parameters in rats. These results suggest that systemic administration of FR134043 would be advantageous over intratracheal administration of FR134043 for the treatment of adult respiratory distress syndrome, septic shock and pulmonary emphysema and other pathophysiologic conditions in which elastases are thought to be involved.

Biochemical and pharmacological characterization of FK706, a novel elastase inhibitor

FK706, sodium 2-[4-[[(S)-1-[[(S)-2-[[(RS)-3, 3, 3-trifluoro-1-isopropyl-2-oxopropyl]aminocarbonyl]pyrrolidin -1-yl]carbonyl]-2-methylpropyl] aminocarbonyl] benzoylamino] acetate, C26H32F3N4NaO7, is a synthetic water-soluble inhibitor of human neutrophil elastase. This compound demonstrated a competitive and slow-binding inhibition of human neutrophil elastase with a Ki of 4.2 nM. In studies using synthetic substrates, FK706 inhibited human neutrophil elastase activity and porcine pancreatic elastase activity with respective IC50 values of 83 and 100 nM. FK706, however, inhibited more weakly, (IC50 values > 340 microM) other serine proteinases such as human pancreatic alpha-chymotrypsin, human pancreatic trypsin and human leukocyte cathepsin G. FK706 also effectively inhibited the hydrolysis of bovine neck ligament elastin (2 mg/ml final concentration) by human neutrophil elastase (4 microg/ml final concentration) with an IC50 value of 230 nM. FK706 protected animals against human neutrophil elastase (50 microg/animal)-induced lung hemorrhage with ED50 values of 2.4 microg/animal by intratracheal administration and 36.5 mg/kg by intravenous administration, respectively. Subcutaneous administration of FK706 significantly suppressed human neutrophil elastase (20 microg/paw)-induced paw edema in mice in a dose-dependent manner (47% inhibition at a dose of 100 mg/kg). These results suggest that FK706 would be a useful tool for investigating the role of human neutrophil elastase in inflammatory disorders associated with an excess of elastase, such as pulmonary emphysema, adult respiratory distress syndrome, septic shock, cystic fibrosis, chronic bronchitis and rheumatoid arthritis.

ONO-5046, an elastase inhibitor, attenuates endotoxin-induced acute lung injury in rabbits

Endotoxin causes acute lung injury resembling acute respiratory distress syndrome. Elastase, as well as reactive oxygen species released from activated neutrophils, are thought to play pivotal roles in the pathogenesis of this lung injury. This study investigated whether ONO-5046, a specific elastase inhibitor, can attenuate acute lung injury induced by endotoxin in rabbits. Thirty-two male anesthetized rabbits were randomly assigned to receive one of four treatments (n = 8 for each group): infusion of saline without ONO-5046 treatment (Group S-S), infusion of saline with ONO-5046 (Group S-O), infusion of Escherichia coli endotoxin (100 micrograms/kg over 60 min) without ONO-5046 (Group E-S), and infusion of endotoxin with ONO-5046 (Group E-O). Fifteen minutes before the infusion of endotoxin (Groups E-O and E-S) or saline (Groups S-S and S-O), the animals received a bolus injection of ONO-5046 (10 mg/kg) followed by continuous infusion (10 mg.kg-1.h-1: Groups S-O and E-O) or saline (Groups S-S and E-S). The lungs of the rabbits were ventilated with 40% oxygen. Hemodynamics, peripheral leukocyte and platelet counts, and PaO2 were recorded during the ventilation period (6 h). Lung mechanics, cell fraction of the bronchoalveolar lavage fluid (BALF), activated complement, cytokines, and arachidonic acid metabolite concentrations in the BALF were measured at 6 h. The wet- to dry (W/D)-weight ratio of the lung and albumin concentrations in BALF were analyzed as indices of pulmonary edema. Endotoxin decreased lung compliance and PaO2, and increased the W/D weight ratio, neutrophil counts, and albumin concentration in the BALF. Concentrations of activated complement C5a, interleukin-6, interleukin-8, and thromboxane B2 in the BALF were increased by the infusion of endotoxin. ONO-5046 treatment attenuated these changes. Endotoxin caused extensive morphologic lung damage, which was lessened by ONO-5046. In conclusion, intravenous ONO-5046 pretreatment attenuated endotoxin-induced lung injury in rabbits. This beneficial effect of ONO-5046 may be due, in part, to a reduction in the levels of mediators that activate neutrophils, in addition to the direct inhibitory effect on elastase.

[Diagnostic value of granulocyte elastase determination in cord blood of newborn infants at risk for maternofetal infection]

BACKGROUND

Polymorphonuclear elastase is an early and sensitive indicator of neonatal infection when performed at the beginning of clinical symptoms.

PATIENTS AND METHODS

To investigate the diagnostic value of elastase measurement in cord blood immediately after birth, 211 neonates (103 boys vs 108 girls, 154 vaginal delivery vs 57 cesarean section). Mean gestational age 38.9 weeks (range: 30-42), mean birth weight 3,260 g (range: 1,430-4,920 g). After clinical, bacterial and biological screening, the infants were classified in three groups. Group A (n = 118): none infectious risk factor neither clinical signs of infection; group B (n = 79): one or more risk factors but no evidence of infection; group C (n = 14): proved or probable infection. Polymorphonuclear elastase was measured in cord blood of all infants using an heterogeneous enzyme-linked-immunosorbent assay.

RESULTS

We observed higher elastase values in group C (176 +/- 67 micrograms/L) than in group A (91 +/- 64 micrograms/L) and B (67 +/- 61 micrograms/L) (mean +/- SD, P = 0.0001). With a cutoff value fixed at 80 micrograms/L, the sensitivity of this test applicated to neonates presenting materno-fetal infectious risk factor(s) was 85% (12/14), specificity 74% (59/79), positive predictive value 37%, and negative predictive value 96%.

CONCLUSION

Because two of the 14 infected infants (15%) were not detected by elastase dosage in cord blood, this test cannot be used as an early indicator of materno-fetal infection.

Impaired activity of protease inhibitors towards neutrophil elastase bound to human articular cartilage

OBJECTIVE

To investigate the effects of protease inhibitors on the ability of free and cartilage bound neutrophil elastase to degrade cartilage proteoglycan in vitro.

METHODS

Cryostat sections of human articular cartilage were used as substrate, and proteoglycan loss induced by free or cartilage bound elastase was quantified by alcian blue staining, followed by scanning and integrating microdensitometry.

RESULTS

High molecular mass protease inhibitors (alpha 1 protease inhibitor, alpha 2 macroglobulin, and soya bean trypsin inhibitor) and synovial fluid from patients with rheumatoid arthritis were effective in blocking proteoglycan loss from sections treated with free elastase, but their activity towards cartilage bound elastase was much reduced. In contrast, low molecular mass elastase inhibitors (N-methoxysuccinyl-Ala-Ala-Pro-Val chloromethyl ketone and ONO-5046 (N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulphonylamino]benzoyl] amino-acetic acid) were effective against free and cartilage bound elastase.

CONCLUSION

The binding of elastase to cartilage appears to be a mechanism whereby the enzyme can remain active in the presence of high molecular mass protease inhibitors.