Proteinase Inhibitor Complex Research Articles

Inhibiting JNK Dephosphorylation and Induction of Apoptosis by Novel Anticancer Agent NSC-741909 in Cancer Cells

NSC-741909 is a recently identified novel anticancer agent that suppresses the growth of several NCI-60 cancer cell lines with a unique anticancer spectrum. However, its molecular mechanisms remain unknown. To determine the molecular mechanisms of NSC-741909-induced antitumor activity, we analyzed the changes of 77 protein biomarkers in a sensitive lung cancer cell line after treatment with this compound by using reverse-phase protein microarray. The results showed that phosphorylation of mitogen-activated protein (MAP) kinases (P38 MAPK, ERK, and JNK) were persistently elevated by the treatment with NSC-741909. However, only the JNK-specific inhibitor SP600125 effectively blocked the apoptosis induced by NSC-741909. Moreover, NSC-741909-mediated apoptosis was also blocked by a dominant-negative JNK construct, suggesting that sustained activation of JNK is critical for the apoptosis induction. Further studies revealed that treatment with NSC-741909 suppressed dephosphorylation of JNK and the expression of MAPK phosphatase-1. Thus, NSC-741909-mediated inhibition of JNK dephosphorylation results in sustained JNK activation, which leads to apoptosis in cancer cells.

Neutrophil elastase reduces secretion of secretory leukoproteinase inhibitor (SLPI) by lung epithelial cells: role of charge of the proteinase-inhibitor complex.

BackgroundSecretory leukoproteinase inhibitor (SLPI) is an important inhibitor of neutrophil elastase (NE), a proteinase implicated in the pathogenesis of lung diseases such as COPD. SLPI also has antimicrobial and anti-inflammatory properties, but the concentration of SLPI in lung secretions in COPD varies inversely with infection and the concentration of NE. A fall in SLPI concentration is also seen in culture supernatants of respiratory cells exposed to NE, for unknown reasons. We investigated the hypothesis that SLPI complexed with NE associates with cell membranes in vitro.MethodsRespiratory epithelial cells were cultured in the presence of SLPI, varying doses of proteinases over time, and in different experimental conditions. The likely predicted charge of the complex between SLPI and proteinases was assessed by theoretical molecular modelling.ResultsWe observed a rapid, linear decrease in SLPI concentration in culture supernatants with increasing concentration of NE and cathepsin G, but not with other serine proteinases. The effect of NE was inhibited fully by a synthetic NE inhibitor only when added at the same time as NE. Direct contact between NE and SLPI was required for a fall in SLPI concentration. Passive binding to cell culture plate materials was able to remove a substantial amount of SLPI both with and without NE. Theoretical molecular modelling of the structure of SLPI in complex with various proteinases showed a greater positive charge for the complex with NE and cathepsin G than for other proteinases, such as trypsin and mast cell tryptase, that also bind SLPI but without reducing its concentration.ConclusionThese data suggest that NE-mediated decrease in SLPI is a passive, charge-dependent phenomenon in vitro, which may correlate with changes observed in vivo.

Cell Surface Detachment of Pregnancy-associated Plasma Protein-A Requires the Formation of Intermolecular Proteinase-Inhibitor Disulfide Bonds and Glycosaminoglycan Covalently Bound to the Inhibitor

The metzincin metalloproteinase pregnancy-associated plasma protein-A (PAPP-A, pappalysin-1) promotes cell growth by proteolytic cleavage of insulin-like growth factor-binding proteins 4 and 5, causing the release of bound insulin-like growth factors. PAPP-A binds an unknown cell-surface heparan sulfate proteoglycan, suggesting that it controls insulin-like growth factor signaling spatially. In human pregnancy, the majority of PAPP-A circulates as a disulfide-bonded complex with its inhibitor, the proform of eosinophil major basic protein (proMBP). Interestingly, Ser-62 of proMBP is substituted with a glycosaminoglycan (GAG) chain, possibly a heparan sulfate type, and the PAPP-A.proMBP complex is unable to bind to the cell surface. We show here that proMBP detaches surface-bound PAPP-A in a process that depends on the proMBP GAG and also on the formation of intermolecular disulfide bonds between PAPP-A and proMBP. Unlike what was expected, we demonstrate that the GAG of proMBP is not required for PAPP-A.proMBP complex formation and that proMBP residues His-137, Ser-178, Arg-179, and Asn-181 are important for the recognition of PAPP-A. Using a mouse model, we find that the half-life of circulating PAPP-A and proMBP in complex is severalfold higher than both of the uncomplexed proteins, further suggesting that the PAPP-A.proMBP complex is formed at the cell surface in vivo rather than in the circulation. Further supporting this, we show that formation of the PAPP-A.proMBP complex at the cell surface proceeds rapidly compared with the slow rate of complex formation in solution. Because both PAPP-A and proMBP are expressed ubiquitously, this model may be applicable to many tissues in which insulin-like growth factor bioavailability is locally regulated.

Proteinase Inhibition by Proform of Eosinophil Major Basic Protein (pro-MBP) Is a Multistep Process of Intra- and Intermolecular Disulfide Rearrangements

The metzincin metalloproteinase pregnancy-associated plasma protein A (PAPP-A, pappalysin-1) promotes cell growth by the cleavage of insulin-like growth factor-binding proteins-4 and -5, causing the release of bound insulin-like growth factors. The proteolytic activity of PAPP-A is inhibited by the proform of eosinophil major basic protein (pro-MBP), which forms a covalent 2:2 proteinase-inhibitor complex based on disulfide bonds. To understand the process of complex formation, we determined the status of cysteine residues in both of the uncomplexed molecules. A comparison of the disulfide structure of the reactants with the known disulfide structure of the PAPP-A.pro-MBP complex reveals that six cysteine residues of the pro-MBP subunit (Cys-51, Cys-89, Cys-104, Cys-107, Cys-128, and Cys-169) and two cysteine residues of the PAPP-A subunit (Cys-381 and Cys-652) change their status from the uncomplexed to the complexed states. Upon complex formation, three disulfide bonds of pro-MBP, which connect the acidic propiece with the basic, mature portion, are disrupted. In the PAPP-A.pro-MBP complex, two of these form the basis of both two interchain disulfide bonds between the PAPP-A and the pro-MBP subunits and two disulfide bonds responsible for pro-MBP dimerization, respectively. Based on the status of the reactants, we investigated the role of individual cysteine residues upon complex formation by mutagenesis of specific cysteine residues of both subunits. Our findings allow us to depict a hypothetical model of how the PAPPA.pro-MBP complex is formed. In addition, we have demonstrated that complex formation is greatly enhanced by the addition of micromolar concentrations of reductants. It is therefore possible that the activity in vivo of PAPP-A is controlled by the redox potential, and it is further tempting to speculate that such mechanism operates under pathological conditions of altered redox potential.

Alkaline Proteinase Inhibitor of Pseudomonas aeruginosa: A MUTATIONAL AND MOLECULAR DYNAMICS STUDY OF THE ROLE OF N-TERMINAL RESIDUES IN THE INHIBITION OF PSEUDOMONAS ALKALINE PROTEINASE

Alkaline proteinase inhibitor of Pseudomonas aeruginosa is a 11.5-kDa, high affinity inhibitor of the serralysin class of zinc-dependent proteinases secreted by several Gram-negative bacteria. X-ray crystallography of the proteinase-inhibitor complex reveals that five N-terminal inhibitor residues occupy the extended substrate binding site of the enzyme and that the catalytic zinc is chelated by the alpha-amino and carbonyl groups of the N-terminal residue of the inhibitor. In this study, we assessed the effect of alteration of inhibitor residues 2-5 on its affinity for Pseudomonas alkaline proteinase (APR) as derived from the ratio of the dissociation and associate rate constants for formation of the enzyme-inhibitor complex. The largest effect was observed at position Ser-2, which occupies the S1' pocket of the enzyme and donates a hydrogen bond to the carboxyl group of the catalytic Glu-177 of the proteinase. Substitution of Asp, Arg, or Trp at this position increased the dissociation constant KD by 35-, 180-, and 13-fold, respectively. Mutation at positions 3-5 of the trunk also resulted in a reduction in enzyme-inhibitor affinity, with the exception of an I4W mutant, which exhibited a 3-fold increase in affinity. Molecular dynamics simulation of the complex formation between the catalytic domain of APR and the S2D mutant showed that the carboxyl of Asp-2 interacts with the catalytic zinc, thereby partially neutralizing the negative charge that otherwise would clash with the carboxyl group of Glu-177 of APR. Simulation of the interaction between the alkaline proteinase and the I4W mutant revealed a major shift in the loop comprised of residues 189-200 of the enzyme that allowed formation of a stacking interaction between the aromatic rings of Ile-4 of the inhibitor and Tyr-158 of the proteinase. This new interaction could account for the observed increase in enzyme-inhibitor affinity.

Stimulation of inflammatory markers after blunt trauma.

Inflammatory mediators are released after trauma and may be related to the pathogenesis of sepsis. A prospective combined study of the pattern of release of an inflammatory mediator, interleukin (IL) 6, leucocyte activation (polymorphonuclear leucocyte (PMN) CD11b receptor expression and plasma elastase-alpha1 proteinase inhibitor complex (E-alpha1PI)) and soluble endothelial adhesion molecule expression (soluble E-selectin (sE-selectin) and soluble intracellular adhesion molecule 1 (sICAM-1)) was performed in patients suffering blunt trauma without adult respiratory distress syndrome (ARDS) or multiple organ failure syndrome (MOFS). Thirty-one patients with a mean Injury Severity Score (ISS) of 14 (range 9-57) were studied. Venous blood samples were collected within 6 h of injury and then at 1, 3, 5 and 7 days. Leucocyte CD11b expression was quantified by flow cytometry. Serum IL-6, plasma E-alpha1PI, sE-selectin and sICAM-1 were measured by enzyme-linked immunosorbent assay. Serum IL-6, CD11b expression and E-alpha1PI levels were significantly raised above control values (P < 0.0001) on admission, slowly returning towards control values over the study period (median IL-6, 140 pg/ml versus undetectable; CD11b, 14.8 versus 6.4 mean channel fluorescence units; E-alpha1 PI, 208 versus 52 microg/l). The sICAM-1 level rose to a median of 539 ng/ml at 5 days (control 243 ng/ml). The median sE-selectin level also progressively increased to a maximum level of 80 ng/ml at 5 days (control 49 ng/ml). Eleven patients developed postoperative sepsis. Significant differences in CD11b expression were seen at days 3, 5 and 7 and in E-alpha1 PI at 6 h, 24 h and 3 days in patients who subsequently developed sepsis (P < 0.05). Severe injury (ISS 16 or greater) was associated with significantly greater responses in these measurements. These data show that markers of inflammation are specifically stimulated by trauma even when ARDS and MOFS do not occur. The CD11b receptor on PMNs may be useful in screening patients destined to develop post-traumatic sepsis.

Lung protection during total cardiopulmonary bypass by isolated lung perfusion: preliminary results of a novel perfusion strategy

Background. The present pilot study was conducted to evaluate the effect of isolated short-term lung perfusion during cardiopulmonary bypass (CPB) on inflammatory response and oxygenation. Methods. A total of 24 patients undergoing elective cardiac surgery with routine CPB were prospectively assigned to three groups. Group I (n = 7), control subjects receiving neither lung perfusion nor ultrafiltration; group II (n = 9), patients undergoing lung perfusion; and group III (n = 8), patients undergoing lung perfusion plus ultrafiltration. Lung perfusion consisted of single-shot hypothermic pulmonary artery perfusion with oxygenated blood. Proteins indicative of leukocyte activation and lung injury were measured in plasma and bronchoalveolar lavage fluid (BALF). The alveolar-arterial oxygen gradient (A-aD o 2) and the oxygenation index (P o 2/Fi o 2) were also determined. Results. Oxygenation values were best preserved in group III, followed by group II. After CPB, elastase-α 1-proteinase inhibitor complex had increased in plasma in all groups; in BALF it increased in groups I and II, but not in group III. α 2-Macroglobulin increased significantly in BALF in group I but not in groups II and III. Conclusions. These preliminary results provide some evidence that single-shot hypothermic lung perfusion with oxygenated blood at the beginning of CPB may have a protective effect on the lungs, especially when combined with ultrafiltration.

Role of Carbohydrate Antigens Sialyl Lewis (a) (CA19-9) in Bronchoalveolar Lavage in Patients with Pulmonary Fibrosis

Background: It has been reported that carbohydrate antigen sialyl Lewis (a) (CA19-9) levels are elevated in serum as well as in bronchoalveolar lavage fluid (BALF) of patients with pulmonary fibrosis. However, the biological significance of CA19-9 is unclear. Objective: The purpose of the present study was to evaluate correlations between CA19-9 levels in BALF and several biochemical as well as clinical parameters in patients with pulmonary fibrosis. In addition, biological functions of CA19-9 were also examined. Methods: We studied 24 patients with a diagnosis of pulmonary fibrosis: 16 with idiopathic pulmonary fibrosis (IPF) and 8 with pulmonary fibrosis associated with a collagen vascular disorder (PF-CVD). In BALF, carbohydrate antigens sialyl Lewis (a) (CA19-9), elastase: α₁-proteinase inhibitor complex (E-PI), hepatocyte growth factor (HGF), LDH, IgG, IgA, albumin, and cell differentiation were measured. We also evaluated the effects of CA19-9 on neutrophil functions. Results: CA19-9/albumin levels in BALF significantly correlated with HGF/albumin, elastase/albumin, LDH/albumin, total number of alveolar macrophages, and total number of neutrophils. Purified CA19-9 had a chemotactic activity for neutrophils. In addition, neutrophil chemotactic activity to C5a, fMLP, and interleukin 8 was significantly stimulated after incubation with purified CA19-9. Furthermore, CA19-9 increased the expression of CD15s on neutrophils. Conclusions: Our data demonstrated (i) CA19-9 in BALF correlated with other markers of inflammation in pulmonary fibrosis, and (ii) CA19-9 can modify neutrophil functions. These results suggest that CA19-9 may play a role in the process of lung injury in patients with pulmonary fibrosis.

Effect of collection and preprocessing methods on neutrophil elastase plasma concentrations.

Elevated plasma levels of the elastase alpha 1-proteinase inhibitor complex (E-alpha 1 PI) have been proposed as a marker of bacterial infection and neutrophil activation. Liberation of elastase from neutrophils after collection of blood may cause falsely elevated results. Collection methods have not been validated for critically ill neonates and children. We evaluated the influence of preanalytical methods on E-alpha 1 PI results including the recommended collection into EDTA tubes. First, we compared varying acceleration speeds and centrifugation times. Centrifugation at 1550 g for 3 min resulted in reliable preparation of leukocyte free plasma. Second, we evaluated all collection tubes under consideration for absorption of E-alpha 1 PI. Finally, 12 sets of samples from healthy adults and 42 sets obtained from critically ill neonates and children were distributed into the various sampling tubes. Samples were centrifuged within 15 min of collection and analyzed with a new turbidimetric assay adapted to routine laboratory analyzers. One of the two tubes containing a plasma-cell separation gel absorbed 22.1% of the E-alpha 1 PI content. In the remaining tubes without absorption of E-alpha 1 PI no differences were observed for samples from healthy adult patients. However, in samples from critically ill neonates or children, significantly higher results were obtained for plain Li-heparin tubes (mean = 183 micrograms/L), EDTA tubes (mean = 93 micrograms/L), and citrate tubes (mean = 88.5 micrograms/L) than for the Li-hep tube with cell-plasma separation gel and no absorption of E-alpha 1 PI (mean = 62.4 micrograms/L, p < 0.01). Contrary to healthy adults, E-alpha 1 PI results in plasma samples from critically ill neonates and children depend on the type of collection tube.

Identification of potential activators of proteinase-activated receptor-2

In order to identify physiological activators of proteinase-activated receptor-2 (PAR-2), a peptide chloromethane inhibitor (biotinyl-Ser-Lys-Gly-Arg-CH 2Cl) based on the cleavage site for activation of PAR-2 was synthesised and tested with 12 trypsin-like serine proteinases. The second-order rate constant ( k i/ K i) for the formation of the covalent proteinase-inhibitor complex varied by 2×10 5-fold between the proteinases. Biotinyl-Ser-Lys-Gly-Arg-CH 2Cl reacted very rapidly with trypsin, acrosin from sperm and tryptase from mast cells: the k i/ K i values with these proteinases were greater than 10 5 M −1 s −1. Thus, the specificity of these proteinases matched the sequence of the activation site of PAR-2 and it can be concluded that these proteinases are potential physiological activators of PAR-2.

In Vitro and in Vivo Biocompatibility of Substituted Cellulose and Synthetic Membranes

Regenerated cellulosic membranes are held as bioincompatible due to their high complement - and leukopenia - inducing properties. Adherence of polymorphonuclear neutrophils and monocyte purified from normal human blood to the three membranes were evaluated in an in vitro recirculation circuit in the presence or absence of fresh, autologous plasma after recirculation in an in vitro circuit using minimodules with each of the three membranes. In in vivo studies, 9 patients were treated with conventional haemodialysis for 2 weeks with each membrane and 1 week for wash-out using haemodialysers with the following surface: 1.95 m2 for benzyl-cellulose, 1.8 m2 for acetate-cellulose and low-flux polysulfone. Measurement of leukopenia, plasma C3a des Arg and elastase-alpha1 proteinase inhibitor complex levels as well as urea, creatinine, phosphate and uric acid clearances was performed. Plasma-free neutrophils adhered maximally to acetate-cellulose (65% remaining in the circulation), while there was no significant difference between low-flux polysulfone and benzyl-cellulose (80% circulating neutrophils, at 15 min, p<0.001 vs acetate cellulose). In the presence of fresh plasma, as source of complement, the differences between acetate cellulose vs polysulfone and benzyl-cellulose were even more evident, suggesting the role of complement-activated products in neutrophil adherence. A similar trend was observed for monocyte adherence with the three membranes in the absence or presence of plasma. In vivo studies showed that the nadir of leukopenia was at 15 and 30 min with acetate-cellulose (79%) and benzyl-cellulose (50%) (p<0.05 acetate- vs benzyl-cellulose) and at 15 min with polysulfone (24%) (p<0.01 vs acetate- and benzyl-cellulose). Plasma C3a des Arg levels arose to 2037 +/- 120 ng/ml, 1216 + 434 ng/ml and 46 +/- 55 ng/ml with acetate-, benzyl-cellulose and polysulfone, respectively. No pre- vs post-dialysis increase in the intracellular content of TNF-alpha was detected with any of three membranes. Clearance values of urea, creatinine and uric acid were superimposable for all the three membranes. However, benzyl cellulose had a significantly higher clearance for phosphorus (normalized for surface area) (p<0.01 vs acetate-cellulose, 0.001 vs polysulfone). These results implicate that synthetic modification of the cellulose polymer as for the benzyl-cellulose significantly reduces the in vitro adherence, delays the in vivo activation of "classic" biocompatibility parameters and notably improves the removal of inorganic phosphorus.

A baboon model for hematologic studies of cardiopulmonary bypass

Objective investigation of new inhibitors of blood protein or cellular systems that are activated during cardiopulmonary bypass (CPB) is impeded by the absence of a satisfactory animal model. Because most baboon hematologic proteins immunologically cross-react with those used for human assays, we developed a robust, reusable baboon model of CPB. Blood samples were obtained from adult baboons at six time intervals before, during, and after 60 minutes of partial CPB at 37°C with peripheral cannulas. Both membrane (n = 7) and bubble oxygenators (n = 7) were investigated. We measured platelet and white blood cell counts; platelet response to adenosine diphosphate and release of β-thromboglobulin; fibrinopeptide A, prothrombin fragment F 1.2, thrombin-antithrombin complex, d-dimer, and plasmin-antiplasmin complex; activated complement (C3b/c and C4b/c); elastase-α 1 proteinase inhibitor complex; and bleeding times. Adherent glycoprotein III a antigen in Triton X-100 washes of the perfusion circuit was also measured. Markers of baboon platelet, complement, and neutrophil activation and thrombosis significantly increased during CPB with bubble oxygenator systems but did not change appreciably in membrane oxygenator circuits. Markers of fibrinolysis, d-dimer, and plasmin-antiplasmin complex did not change with either oxygenator. The baboon model of CPB, when a bubble oxygenator is used, is a robust, reusable animal model for evaluating inhibitors of platelet, complement, and neutrophil activation and thrombosis during and after CPB.

Hepatocyte growth factor and neutrophil elastase in idiopathic pulmonary fibrosis

It has been hypothesized that hepatocyte growth factor (HGF) may play an important role in regulating the growth of lung epithelium and in the regeneration of the lung as a paracrine or endocrine factor in idiopathic pulmonary fibrosis (IPF). Based on this background, serum HGF was measured in 31 IPF patients (21 male/10 female, median age 60 years). Fifteen age-matched normal non-smokers served as the control. Hepatocyte growth factor was measured by enzyme-linked immunosorbent assay with monoclonal and polyclonal antibodies against human HGF (Otsuka Assay Laboratories, Tokushima, Japan). Elastase: α 1-proteinase complex was also measured by enzyme-linked immunosorbent assay. No patients had significant liver or renal dysfunction. As a result, mean (standard error) serum HGF concentration of the patients with IPF was 0·384 (0·022) ng ml −1, which was significantly high compared to normal non-smokers [0·213 (0·012) ng ml −1, P<0·001, 95% confidence interval was between 0·104 and 0·238]. Serum HGF values correlated strongly with the plasma elastase: α 1 proteinase inhibitor complex ( R=0·679, P<0·001). Immunohistochemical staining of lung tissue with anti-human neutrophil elastase showed scattered immunopositive cells mainly in interstitium. Immunohistochemical staining with mouse anti-human HGF antibody showed that HGF was distributed to the lung epithelial cells in IPF lung specimens obtained by open lung biopsy. These results suggest that HGF may play an important role in the pathogenesis of IPF.

Interleukin 8 and granulocyte elastase in the tracheobronchial aspirate of infants without respiratory distress syndrome or intrauterine infection and development of chronic lung disease.

To elucidate the mechanism of the development of chronic lung disease (CLD) in infants without respiratory distress syndrome or intra-uterine infection, we serially measured the concentrations of interleukin 8 (IL-8) and granulocyte elastase alpha 1 proteinase inhibitor complex (E-alpha 1 PI) and elastase activity in the tracheobronchial aspirate of very low birth weight infants without respiratory distress syndrome or intra-uterine infection until day 28. IL-8 concentration and elastase activity between day 21 and 28 in infants who developed CLD later were significantly higher compared with those in infants who did not develop CLD. E-alpha 1 PI concentration between day 25 and 28 in infants who developed CLD later was significantly higher compared with those in infants who did not develop CLD. The area under the curve of the IL-8 and E-alpha 1 PI concentrations and elastase activity between day 1 and day 28 in infants with CLD was significantly higher than those in infants without CLD. These data suggest that the lung tissue injury caused by the enzymes from neutrophils accumulated and activated by IL-8 also play an important role in the development of this type of CLD.

Plasma vitamin C concentrations in patients with cystic fibrosis: evidence of associations with lung inflammation

Vitamin C status and possible associations with the disease process in cystic fibrosis (CF) patients were investigated. Plasma vitamin C concentrations in patients from two different mid-European populations (Swiss, n = 62; Austrian, n = 60) taking no or low-dose vitamin C from multivitamin supplements did not differ from each other or from control subjects (n = 34). Vitamin C concentrations decreased with age (5.05 mumol.L-1, y-1). When followed up for 12 mo, patients had the highest plasma vitamin C concentrations in February and the lowest in May and August (P < 0.01); the decrease in vitamin C was accompanied by increases in plasma malondialdehyde (P < 0.001) and tumor necrosis factor alpha concentrations (P < 0.01). During supplementation with vitamin E for 2 mo or beta-carotene for 12 mo vitamin C concentrations did not change. They correlated inversely with white blood cell count (r = -0.36, P = 0.008), bands (r = -0.36, P = 0.02), alpha 1-acid glycoprotein (r = -0.45, P = 0.002), interleukin 6 (r = -0.46, P = 0.0006), and neutrophil elastase/alpha 1-proteinase inhibitor complexes (r = -0.34, P = 0.02). In patients with vitamin C concentrations < 40 mumol/L, all indexes of inflammation were relatively high, whereas those with concentrations > 80 mumol/L (upper quartile of control subjects) showed clearly lower values. These results are consistent with the hypothesis that by scavenging oxygen free radicals vitamin C interacts with an inflammation-amplifying cycle of activation of alveolar macrophages and neutrophils, release of proinflammatory cytokines and oxygen free radicals, and inactivation of antiproteases.

DISCREPANCY BETWEEN LATEX AND ELISA D-DIMER VALUES IN SEPSIS MAY BE CAUSED BY HUMAN NEUTROPHIL ELASTASE

We have recently shown that D-dimers are degraded by human neutrophil elastase (HNE) in vitro, causing rapid decrease in the D-dimer levels measured by a Latex test, but not with an ELISA test employing the same monoclonal antibody against D-dimer. To see if such discrepant D-dimer concentrations occurred in patients with high HNE concentration, we examined 80 plasma samples from 8 patients with sepsis with a Latex and an ELISA test and calculated the ratio between the D-dimer values obtained with the two tests. Twenty healthy pregnant and twenty pre-eclamptic patients, who are known to have raised D-dimer but low HNE concentrations, were chosen as controls. HNE levels were estimated by determining the HNE-alpha 1-proteinase inhibitor complex (HNE-A1PI) concentration. HNE-A1PI concentration was increased in sepsis patients compared with pre-eclamptic patients (p<0.0005) and healthy pregnant women (p<0.0005). In sepsis patients, the D-dimer results were skewed towards lower ratios between Latex and ELISA values compared to pre-eclamptic patients (p=0.008) and healthy pregnant women (p=0.0001). In plasma samples from patients with the largest discrepancy between Latex and ELISA D-dimer values, Western blotting with immunostaining indicated degradation of D-dimers to D-like fragments similar to those observed following degradation of cross-linked fibrin by HNE in vitro. We conclude that in sepsis patients there is a marked discrepancy between Latex and ELISA D-dimer values that may be caused by HNE. In such patients Latex D-dimer assays may cause severe underestimation of fibrinolysis. © 1997 Elsevier Science Ltd

Elastase from polymorphonuclear leukocyte in articular cartilage and synovial fluids of patients with rheumatoid arthritis.

Objective was to study the significance and the mechanism of action of elastase from polymorphonuclear leukocyte (PMN elastase) in patients with rheumatoid arthritis (RA). The experiments conducted consisted of two phases. Firstly, articular cartilage and synovia from 8 patients with RA undergoing total knee replacement were obtained, and the gelatinolytic enzyme activity was extracted with 2M guanidine hydrochloride. The gelatinolytic activity of each tissue was measured to confirm that the activity was due to PMN elastase by using an antihuman leukocyte elastase antibody. Secondly, the levels of PMN elastase-alpha 1 proteinase inhibitor complex (EIC) in the blood and synovial fluid of 170 patients with RA were measured by immunoassay. The results were as follows: 1. Gelatinolytic activity was shown to be mainly due to PMN elastase, and found to be highest in cartilage and synovia in RA joints. 2. The EIC levels in plasma of RA patients were significantly higher than those in gout and osteoarthritis (OA), and the EIC levels increased according to the stage of articular cartilage destruction. Moreover, the EIC levels in synovial fluid of RA patients were higher compared to those of OA patients. The activity of PMN elastase was elevated in destructive joints of RA. With the progression of articular cartilage destruction, EIC levels in plasma of RA patients increased as well. We suggest that PMN elastase may play a significant role in RA disease.

Long-term Follow-up of Hemostatic Molecular Markers during Remission Induction Therapy with All-Trans Retinoic Acid for Acute Promyelocytic Leukemia

Hemostatic molecular markers were serially monitored in a prospective fashion during remission induction therapy with all-trans retinoic acid (ATRA) in sixteen patients with acute promyelocytic leukemia (APL). One patient with leukocytosis before treatment and three patients who later developed hyperleukocytosis also received chemotherapy with behenoyl Ara-C and daunorubicin. Plasma levels of E-fragment of fibrin and fibrinogen degradation product (FDP-E), FDP-D dimer (D-D), thrombin-antithrombin complex (TAT), and plasmin-alpha 2 plasmin inhibitor complex (PIC) were markedly elevated in all but one patient before treatment, and these parameters decreased to normal or near normal ranges in most patients within the first 7 days of treatment. Interestingly, we have found that these parameters were again elevated during the later course of ATRA therapy (after day +7) in eleven patients for various reasons including cytotoxic chemotherapy (3 cases), fever (5 cases; 2 cases with apparent infection, 3 cases without known etiology), Caesarean section (1 case), and no apparent etiology (2 cases). Three patients showed bleeding complications during re-elevation of molecular markers, but none developed thrombosis. Plasma elastase-alpha 1 proteinase inhibitor complex (E-alpha 1 PI) was markedly elevated in all patients at diagnosis and did not decrease significantly during ATRA therapy. Plasma tissue factor antigen was mildly elevated in one out of four patients studied, and thrombomodulin was elevated in two out of ten patients tested. These results confirmed the rapid normalization of coagulopathy during the early phase of remission induction therapy with ATRA but suggest that re-elevation of molecular markers occurs frequently during the later course of ATRA therapy.

Interleukin 8 and granulocyte elastase alpha 1 proteinase inhibitor complex in the tracheobronchial aspirate of infants with chronic lung disease following respiratory distress syndrome.

In order to elucidate the role of interleukin 8 (IL-8) on the development of chronic lung disease (CLD) in neonates following an episode of respiratory distress syndrome (RDS), serial and simultaneous measurements of the concentration of IL-8 and granulocyte elastase alpha 1 proteinase inhibitor complex (E-alpha 1 PI) in the tracheobronchial aspirate of very low birthweight infants with RDS were conducted. The concentration of IL-8 and E-alpha 1 PI in infants with CLD was low in the first 48 h of life, but dramatically increased after 48 h. The concentration of IL-8 between 48 h of life and day 5 was significantly correlated to the fraction of inspired oxygen concentration (FiO2) within 48 h of age, but not to the mean airway pressure. Interleukin 8 seemed to stimulate neutrophils to release granulocyte elastase which, in turn, caused lung tissue injury, resulting in the development of CLD. It is suggested that high FiO2 is an important factor causing IL-8 production in the lung.

Neutrophil elastase/alpha 1-proteinase inhibitor complex levels decrease in plasma of cystic fibrosis patients during long-term oral beta-carotene supplementation.

Lung inflammation in cystic fibrosis (CF) is associated with an increased release from activated neutrophils of oxidants and proteinases. Free radical generation is not efficiently neutralized, and the major anti-proteinase, alpha 1-proteinase inhibitor (alpha 1-PI) is thought to be oxidatively inactivated. We hypothesized that enhanced antioxidant protection could represent an additional long-term strategy to attentuate the host inflammatory response. The effect on plasma neutrophil elastase/alpha 1-PI (NE/alpha 1-PI) complex levels (as a marker of lung inflammation) and plasma malondialdehyde concentrations (as a marker of lipid peroxidation) of additional oral beta-carotene supplementation was studied in 33 CF patients who had already received long-term vitamin E supplementation. In the presence of a more than 10-fold increase in plasma beta-carotene concentrations (mean +/- SEM) (0.09 +/- 0.01 to 1.07 +/- 0.19 mumol/L; p < 0.0001), a small increase in plasma alpha-tocopherol concentrations (23.8 +/- 1.31 to 28.4 +/- 1.81 mumol/L; p = 0.02), and a more than 50% decrease in plasma malondialdehyde concentrations (1.00 +/- 0.07 to 0.46 +/- 0.03 mumol/L; p < 0.0001), plasma NE/alpha 1-PI complex levels decreased from 102.2 +/- 16.0 to 83.0 +/- 10.4 micrograms/L; (p = 0.02). Plasma retinol concentrations increased (1.05 +/- 0.06 to 1.23 +/- 0.07 mumol/L; p = 0.0001) due to conversion of beta-carotene to retinol, which could have contributed to the decrease in NE/alpha 1-PI complex levels. Based on these results, we speculate that efficient antioxidant supplementation could attenuate lung inflammation in CF.