Elevation of plasma truncated elastase alpha 1-proteinase inhibitor complexes in patients with inflammatory lung diseases

α1-Antitrypsin: Key Player or Bystander in Acute Respiratory Distress Syndrome?

Acute respiratory distress syndrome is characterized by hypoxemia, altered alveolar-capillary permeability, and neutrophil-dominated inflammatory pulmonary edema. Despite decades of research, an effective drug therapy for acute respiratory distress syndrome remains elusive. The ideal pharmacotherapy for acute respiratory distress syndrome should demonstrate antiprotease activity and target injurious inflammatory pathways while maintaining host defense against infection. Furthermore, a drug with a reputable safety profile, low possibility of off-target effects, and well-known pharmacokinetics would be desirable. The endogenous 52-kd serine protease α1-antitrypsin has the potential to be a novel treatment option for acute respiratory distress syndrome. The main function of α1-antitrypsin is as an antiprotease, targeting neutrophil elastase in particular. However, studies have also highlighted the role of α1-antitrypsin in the modulation of inflammation and bacterial clearance. In light of the current SARS-CoV-2 pandemic, the identification of a treatment for acute respiratory distress syndrome is even more pertinent, and α1-antitrypsin has been implicated in the inflammatory response to SARS-CoV-2 infection.

Neutrophil elastase in bronchiectasis

The role of neutrophil elastase (NE) is poorly understood in bronchiectasis because of the lack of preclinical data and so most of the assumptions made about NE inhibitor potential benefit is based on data from CF. In this context, NE seems to be a predictor of long-term clinical outcomes and a possible target of treatment. In order to better evaluate the role of NE in bronchiectasis, a systematic search of scientific evidence was performed.Two investigators independently performed the search on PubMed and included studies published up to May 15, 2017 according to predefined criteria. A final pool of 31 studies was included in the systematic review, with a total of 2679 patients. For each paper data of interest were extracted and reported in table.In this review sputum NE has proved useful as an inflammatory marker both in stable state bronchiectasis and during exacerbations and local or systemic antibiotic treatment. NE has also been associated with risk of exacerbation, time to next exacerbation and all-cause mortality. This study reviews also the role of NE as a specific target of treatment in bronchiectasis. Inhibition of NE is at a very early stage and future interventional studies should evaluate safety and efficacy for new molecules and formulations.

Plasma Neutrophil Elastase, α1-Antitrypsin, α2-Macroglobulin and Neutrophil Elastase-α1-Antitrypsin Complex Levels in patients with Dengue Fever

Dengue fever (DF) is characterized by systemic inflammatory response including neutrophil activation leading to uncontrolled elastase activity. This study was aimed to measure the activity of plasma neutrophil elastase (NE), its endogenous inhibitors α₁-antitrypsin (α₁-AT) and α₂-macroglobulin (α₂-MG) and elastase in complex with α₁-AT (NE-α₁-AT complex) in DF. 50 dengue patients [39 DF and 11 dengue hemorrhagic fever (DHF)] and 52 healthy subjects were included in the study. NE was measured using N-succinyl-tri-alanine-p-nitroanilide as substrate. α₁-AT, α₂-MG and NE-α₁-AT complex were estimated by ELISA. The result analysis indicated that the dengue patients had significantly higher elastase activity with significantly reduced inhibitor levels compared to controls. Between DF and DHF patients, DHF group had significantly higher elastase activity. In conclusion, significantly elevated NE and reduced inhibitors level in dengue fever indicate these parameters could be of significance in DF particularly for the assessment of progression of inflammatory processes.

Lung disease at diagnosis in infants with cystic fibrosis detected by newborn screening

RATIONALE

The promise of newborn screening (NBS) for cystic fibrosis (CF) has not been fully realized, and the extent of improvement in respiratory outcomes is unclear. We hypothesized that significant lung disease was present at diagnosis.

OBJECTIVES

To determine the extent of lung disease in a geographically defined population of infants with CF diagnosed after detection by NBS.

METHODS

Fifty-seven infants (median age, 3.6 mo) with CF underwent bronchoalveolar lavage and chest computed tomography (CT) using a three-slice inspiratory and expiratory protocol.

MEASUREMENTS AND MAIN RESULTS

Despite the absence of respiratory symptoms in 48 (84.2%) of infants, a substantial proportion had lung disease with bacterial infection detected in 12 (21.1%), including Staphylococcus aureus (n = 4) and Pseudomonas aeruginosa (n = 3); neutrophilic inflammation (41. 4 x 10(3) cells/ml representing 18.7% of total cell count); proinflammatory cytokines, with 44 (77.2%) having detectable IL-8; and 17 (29.8%) having detectable free neutrophil elastase activity. Inflammation was increased in those with infection and respiratory symptoms; however, the majority of those infected were asymptomatic. Radiologic evidence of structural lung disease was common, with 46 (80.7%) having an abnormal CT; 11 (18.6%) had bronchial dilatation, 27 (45.0%) had bronchial wall thickening, and 40 (66.7%) had gas trapping. On multivariate analysis, free neutrophil elastase activity was associated with structural lung disease. Most children with structural lung disease had no clinically apparent lung disease.

CONCLUSIONS

These data support the need for full evaluation in infancy and argue for new treatment strategies, especially those targeting neutrophilic inflammation, if the promise of NBS for CF is to be realized.

Association of plasma neutrophil elastase levels with other inflammatory mediators and clinical features in adult patients with moderate and severe pneumonia

BACKGROUND

Plasma levels of neutrophil elastase (NE) are elevated in several inflammatory diseases and thus this enzyme might be a critical inflammatory marker. However, the role of NE in the pathogenesis of pneumonia has not been determined. The association between the severity of pneumonia and blood levels of inflammatory markers could be relevant to developing a useful indicator of severity and new therapeutic strategies for pneumonia.

METHODS

We searched for a useful predictive marker and a new therapeutic strategy against pneumonia, using a prospective, multicenter, population-based investigation. Several inflammatory markers in the circulation including NE, cytokines, defensins, C-reactive protein (CRP) and white blood cell (WBC) counts as well as clinical features were prospectively monitored in 28 adult patients with moderate (n=11) and severe pneumonia (n=17) over a period of 14 days.

RESULTS

The value of plasma NE was the highest at entry and significantly declined 2 days later. Trends of cytokines, defensins, CRP and WBC counts were similar but blunter. Microorganisms and the outcome of initial treatment did not significantly affect plasma NE levels. Baseline values of plasma NE were significantly higher in severe, than in moderate pneumonia and this difference between the two types of pneumonia persisted longer than those of any other markers.

CONCLUSIONS

Neutrophil elastase appears to play a critical role in severe pneumonia and determination of its concentration in blood could be a useful indicator of severity. Furthermore, clinical trials of anti-NE drugs in patients with severe pneumonia should be promising.

Role of human neutrophil peptides in the initial interaction between lung epithelial cells and CD4+ lymphocytes

Human neutrophil peptides (HNP) exert immune-modulating effects. We hypothesized that HNP link innate and adaptive immunity through activation of costimulatory molecules. Human lung epithelial cells and CD4+ lymphocytes were treated with HNP separately or in coculture. Stimulation with HNP induced an increase in cell surface expression of CD54 (ICAM-1), CD80, and CD86 on lung epithelial cells and the corresponding major ligands, CD11a (LFA-1), CD152 (CTLA-4), and CD28 on CD4+ lymphocytes. There was an increased nuclear expression of the transcription factor p53 in human alveolar A549 cells and an elevated NF-kappaB (p50) and a degradation of I-kappaB protein in CD4+ lymphocytes following HNP stimulation. HNP enhanced the interaction between A549 cells and CD4+ lymphocytes by increasing cell adhesion and release of IFN-gamma, IL-2, and IL-8. This was attenuated by using an alpha1-proteinase inhibitor to neutralize HNP. We conclude that HNP play an important role in linking innate to acquired immunity by activation of costimulatory molecules in lung epithelial cells and CD4+ lymphocytes.

Pilot Study of the Effects of ONO-5046 in Patients with Acute Respiratory Distress Syndrome

Evidence has linked neutrophil elastase to acute respiratory distress syndrome (ARDS), suggesting that inhibiting the activity of this enzyme could prevent the development and progression of ARDS. However, few clinical trials have examined this notion. We therefore examined the effects of ONO-5046 (sivelestat, a specific inhibitor of neutrophil elastase; sodium N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulfonylaminobenzoyl]amino-acetate tetrahydrate]) in a randomized, double-blinded trial in patients with ARDS. We randomly assigned 24 patients with ARDS to groups that received conventional therapy without or with sivelestat (0.2 mg. kg(-1). h(-1)) for 14 days. The variables of interest associated with clinical outcome were the duration of mechanical ventilation; changes in oxygenation from baseline; changes in cytokine levels from baseline; number of patients alive at 30 days who did not need mechanical ventilation; and mortality rate. The length of intensive care unit stay, number of ventilation days, and mortality rates did not statistically differ between groups. ARDS was more persistent in the control than in the sivelestat group (control, 19.5 +/- 7.4 days; sivelestat, 13.5 +/- 5.9 days; P = 0.039). Neutrophil elastase activity significantly differed between groups at 72 h after treatment. Levels of interleukin-6 were lower in the sivelestat group than in the controls at 24, 48, and 72 h after treatment. ONO-5046 apparently did not affect survival or the duration of mechanical ventilation.

Effects of Noninhibitory α-1-Antitrypsin on Primary Human Monocyte Activation in Vitro

A major function of alpha-1-antitrypsin (AAT) is the inhibition of overexpressed serine proteinases during inflammation. However, it is also known that the biological activity of AAT is affected by chemical modifications, including oxidation of the reactive-site methionine, polymerization, and cleavage by unspecific proteases, all of which will result in AAT inactivation and/or degradation. All inactive forms of AAT can be detected in tissues and fluids recovered from inflammatory sites. To test for a possible link between the inflammation-generated, noninhibitory, cleaved form of AAT and cellular processes associated with inflammation, we studied the effects of this form at varying concentrations on human monocytes in culture. We found that cleaved AAT at concentrations ranging between 1 and 10 microM in monocyte cultures over 24 h induces elevation in monocyte chemoattractant protein-1 (MCP-1) and pro-inflammatory cytokines such as TNFalpha and IL-6 and also increases production of interstitial collagenase (MMP-1) and gelatinase B (MMP-9), members of two different classes of matrix metalloproteinase. Moreover, monocytes stimulated with higher doses of cleaved AAT show an increase in cellular oxygen consumption by about 30%, while native AAT under the same experimental conditions inhibits oxygen consumption by about 50%. These results indicate that the cleaved form of AAT may play a role in monocyte recruitment and pro-inflammatory activation during inflammatory processes, and also suggest that changes in structure occurring upon AAT cleavage could alter its functional properties with potential pathological consequences.

Source of elastin-degrading enzymes in mycotic aortic aneurysms: bacteria or host inflammatory response?

Elastolytic matrix metalloproteinases play a central role in the development of chronic atherosclerotic aortic aneurysms, but mycotic aortic aneurysms are a distinct and unusual form of aneurysm disease caused by bacterial infection. Mycotic aortic aneurysms follow a more rapid and unpredictable course than chronic aneurysm disease and they exhibit a predilection for the suprarenal aorta, further implying unique pathophysiologic mechanisms. The purpose of this study was to examine the nature and source of elastin-degrading enzymes in mycotic aortic aneurysm. Bacterial isolates and aortic tissues were obtained from four consecutive patients undergoing surgical repair of suprarenal mycotic aortic aneurysm. Using an in vitro 3H-labeled elastin degradation assay, elastin-degrading enzyme activity was only observed in the bacteria-conditioned medium from an isolate of Pseudomonas aeruginosa. Elastin-degrading enzyme activity in the aortic tissue homogenate of this patient was abolished by the serine protease inhibitor, phenylmethylsulfonyl fluoride, but it was not suppressed by the metalloproteinase inhibitor, ethylenediamine tetraacetic acid (EDTA). In contrast, elastin-degrading enzyme activity in the bacterial-conditioned medium was decreased by about half by both phenylmethylsulfonyl fluoride and EDTA. Elastin substrate zymography revealed two phenylmethylsulfonyl fluoride-inhibitable elastin-degrading enzyme activities in the aortic tissue homogenate that corresponded to human neutrophil elastase (approximately 30 kDa) and its stable complex with alpha 1-proteinase inhibitor (approximately 80 kDa), but no activity attributable to Pseudomonas elastase, a 33-kDa metal-dependent enzyme. Human neutrophil elastase was readily detected throughout mycotic aortic aneurysm tissues by immunohistochemistry, but elastolytic metalloproteinases were only occasionally observed. The results of this study suggest that the elastin-degrading enzyme produced in mycotic aortic aneurysm are largely serine proteases of host neutrophil origin, rather than elastases produced by the infecting microorganisms or the macrophage-derived metalloproteinases typically observed in atherosclerotic aneurysm disease. Further studies will be needed to extend these findings to a larger number of patients with mycotic aortic aneurysm and those caused by additional microorganisms.

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.

Oxidant-antioxidant balance in granulocytes during ARDS. Effect of N-acetylcysteine

The production of cytotoxic oxygen radicals by activated granulocytes is a proposed mechanism of lung injury in ARDS. Protective effects of N-acetylcysteine (NAC) have been described in experimental and clinical ARDS. NAC could act in part by replenishing the intracellular stores of glutathione (GSH) in activated granulocytes, leading to detoxification of oxygen radicals produced by these cells. To test this hypothesis, 16 patients in the early phase of ARDS were randomized to receive either NAC (n = 8) or placebo (n = 8); granulocyte GSH, granulocyte oxygen radical production, and plasma levels of granulocyte elastase were measured in blood samples drawn sequentially within 8 h after the onset of ARDS (day 0), and then 24 (day 1), 72 (day 3), and 120 h (day 5) after the first sample; treatment with NAC or placebo was started immediately after day 0 and stopped just after day 3. Granulocyte GSH was significantly higher on days 1 and 3 when NAC was received by the patient. Unstimulated oxygen radical production, as measured ex vivo by luminol- and lucigenin-amplified chemiluminescence (CL), was higher in granulocytes from ARDS patients than from healthy control subjects, but was not influenced by NAC. The plasma levels of granulocyte elastase were five to eight times above the upper normal limit on day 0, decreased steadily until day 5, and were uninfluenced by NAC. In summary, parenteral NAC treatment started within 8 h of diagnosis increases the intracellular GSH in the granulocytes of ARDS patients without decreasing spontaneous oxidant production by these cells. The mechanisms of the protective effects of this drug previously reported in experimental and clinical ARDS remain to be established.

The value of polymorphonuclear elastase in adult respiratory distress syndrome

The clinical usefulness of quantitative plasma polymorphonuclear elastase (PMN-elastase) determinations as prognostic markers of adult respiratory distress syndrome (ARDS) in polytraumatized patients was analyzed. PMN-elastase and C-reactive protein (CRP) levels were determined in 55 polytraumatized patients admitted into the Intensive Care Unit. Eight patients developed ARDS and 47 patients did not. These parameters were also analyzed in a control group (n = 34). PMN-elastase levels in ARDS cases reached significantly higher values than in patients who did not develop this syndrome (P < 0.01). We conclude that the increase in plasma PMN-elastase levels can be useful in predicting the development of ARDS in polytraumatized patients, in instituting prophylactic actions and monitoring the course of the disease in these high risk patients. This test is easily adaptable to the routine of any hospital laboratory.

Measurements of plasma elastase alpha 1-proteinase inhibitor complexes in patients receiving cancer chemotherapy with granulocyte colony-stimulating factor

We monitored the plasma elastase alpha 1-proteinase inhibitor complex levels in 21 patients with primary lung cancer who received combination chemotherapy with or without recombinant human granulocyte colony-stimulating factor (rhG-CSF), and 15 normal nonsmokers as controls. Of the 21 patients, 14 received combination chemotherapy without rhG-CSF (among them, 6 developed pneumonia) and 7 received combination chemotherapy with rhG-CSF (among them, 1 developed pneumonia). We measured peripheral WBC counts, C-reactive protein (CRP) levels, plasma elastase alpha 1-proteinase inhibitor complex (complex) levels, and complex/WBC values during cancer chemotherapy. In patients who received cancer chemotherapy without rhG-CSF and had no complications (n = 8), WBC values decreased after chemotherapy, and then gradually increased. Complex levels also decreased slightly after chemotherapy and gradually recovered. The value obtained from dividing the complex concentration by WBC count (complex/WBC value) remained stable during cancer chemotherapy. In patients who received cancer chemotherapy with rhG-CSF and had no complications (n = 6), WBC values decreased after chemotherapy, and then rapidly increased to abnormally high values. Complex levels also decreased slightly after chemotherapy and rapidly increased to abnormally high values together with the WBC counts. The complex/WBC values remained stable during cancer chemotherapy. In patients who developed pneumonia during cancer chemotherapy with or without rhG-CSF (n = 7), their complex levels, complex/WBC values, and CRP levels were elevated at the onset of pneumonia. The maximum complex levels (the highest levels during chemotherapy) were significantly higher in patients who received cancer chemotherapy with rhG-CSF and did not develop pneumonia (583.1 +/- 114.5 ng/mL) and in patients who developed pneumonia during cancer chemotherapy (516.7 +/- 113.2 ng/mL), compared with normal nonsmokers (130.2 +/- 5.5, p < 0.01) and patients who received cancer chemotherapy without rhG-CSF and did not develop complications (211.5 +/- 23.3, p < 0.01). The maximum complex/WBC values were not increased in patients who received cancer chemotherapy with rhG-CSF (0.08 +/- 0.01) and patients who received cancer chemotherapy without rhG-CSF (0.092 +/- 0.01, p < 0.01). The maximum complex/WBC values were significantly higher in patients with pneumonia (0.56 +/- 0.12) compared with normal nonsmokers (0.026 +/- 0.002, p < 0.01) and patients without complications. These findings suggest that although rhG-CSF increases total plasma elastase burden, increased release of neutrophil elastase from individual neutrophils does not take place in vivo in the absence of pneumonia.

Acute lung inflammation: neutrophil elastase versus neutrophils in the bronchoalveolar lavage--neutrophil elastase reflects better inflammatory intensity

OBJECTIVE

To test the hypothesis whether PMN-Elastase in bronchoalveolar lavage fluid (BALF) could reflect neutrophil activity in the lower respiratory tract.

DESIGN

Prospectively, morphologic findings of acute and chronic inflammation in the transbronchial lung biopsy specimens were compared with the numbers of neutrophils in the BALF and the concentration of PMN-Elastase in the same.

SETTING

Ambulatory outpatient service of bronchology and respiratory physiopathology and intensive care unit of a communal hospital.

PATIENTS

50 ambulatory outpatients and 10 critically ill patients of the ICU, presenting infiltrative lung diseases.

INTERVENTIONS

Transbronchial lung biopsies and bronchoalveolar lavage were performed through a fiberoptic bronchoscope. Venous blood samples were obtained after bronchoscopy.

MEASUREMENTS AND RESULTS

Biopsy specimens and cell count in the BALF were examined by light microscopy. PMN-Elastase and albumin were measured in the BALF-supernatant and in the plasma. C-reactive protein (CRP) and a1 proteinase inhibitor (a1-PI) were measured in the plasma. Intrapulmonary originating PMN-Elastase was calculated with reference to albumin. The results concerning acute inflammation obtained by transbronchial lung biopsy (TBLB) (n = 16) correlated better with the levels of PMN-Elastase in the BALF (n = 21) than with the neutrophil count (n = 28) (p < 0.5 versus p < 0.025 for chi 2). The sensitivities and specificities of the above methods were respectively 76.9%, 100%, 100% and 100%, 95.2%, 63.1%. The intrapulmonary originating PMN-Elastase was about 99.7% of the measured BALF-Elastase.

CONCLUSION

The PMN-Elastase concentration in the BALF is a more accurate indicator of the inflammatory intensity in the alveolar structures than in the number of neutrophils. It may therefore be useful to the clinician in his attempt to detect acute inflammation in the lower respiratory tract.

Serial measurements of plasma elastase alpha 1-proteinase inhibitor complexes in patients receiving cancer chemotherapy

We monitored the plasma elastase:alpha 1-proteinase inhibitor complexes during chemotherapy for cancer and investigated the relationship between the elastase burden and the onset of adult respiratory distress syndrome (ARDS) in 20 patients with primary lung cancer who received combination chemotherapy; 15 normal nonsmokers served as controls. Of the 20 patients, 6 developed pneumonia, and 6 developed ARDS. We measured peripheral WBCs, C-reactive protein (CRP), plasma elastase:alpha 1-proteinase inhibitor complex (complex), and the ratio of complex/WBC during chemotherapy for cancer. In patients who did not experience complications during combination chemotherapy, WBC counts changed, but levels of complex were normal. In patients who developed pneumonia, levels of complex were abnormally high during the WBC nadir, and the complex/WBC count increased along with the level of CRP. In patients who developed ARDS during chemotherapy for cancer, levels of complex were abnormally high immediately after chemotherapy and remained high after the onset of ARDS. In addition, complex/WBC counts and CRP levels increased at the onset of ARDS. The maximum complex concentration was significantly higher in patients with pneumonia (414.3 +/- 57.2 ng/ml) and ARDS (683.2 +/- 72.8 ng/ml), compared with normal nonsmokers (130.2 +/- 5.5 ng/ml; p < 0.01) and patients who did not develop complications (211.5 +/- 23.3 ng/ml; p < 0.01). The maximum complex/WBC count was also significantly higher in patients with pneumonia (0.56 +/- 0.12) and ARDS (1.03 +/- 0.27), compared with normal nonsmokers (0.03 +/- 0.002; p < 0.01) and patients without complications (0.09 +/- 0.01; p < 0.01). These findings suggested a possible correlation between increased levels of complex and the onset of ARDS.