Secretory leukoprotease inhibitor: partnering alpha 1-proteinase inhibitor to combat pulmonary inflammation

Secretory leukoprotease inhibitor (SLPI) is a low molecular weight serine proteinase inhibitor, notably of neutrophil elastase (NE), which is synthesised and secreted by the pulmonary epithelium. SLPI plays an important role in limiting NE-induced pulmonary inflammation and, significantly, it also possesses anti-HIV activity. SLPI is a significant component of the anti-NE shield in the lung which has different reactivity from, and is therefore complementary to, the anti-NE action of alpha 1-proteinase inhibitor (alpha 1-PI). Inhaled recombinant SLPI (rSLPI) could prove beneficial in partnership with alpha 1-PI in the treatment of a number of inflammatory lung disorders including emphysema, chronic bronchitis, cystic fibrosis, and adult respiratory distress syndrome.     

Long-term therapy of alpha 1-antitrypsin-deficiency-associated pulmonary emphysema with human alpha 1-antitrypsin

alpha 1-antitrypsin (alpha 1-AT) deficiency is a genetic disorder characterized by low serum levels of alpha 1-AT and a high risk of pulmonary emphysema at a young age. The resulting surplus of proteases, mainly of neutrophil elastase, can be balanced by i.v. augmentation with alpha 1-AT. However, it is not clear if affected patients benefit from long-term augmentation therapy and no long-term safety data are available. We examined 443 patients with severe alpha 1-AT deficiency and pulmonary emphysema receiving weekly i.v. infusions of 60 mg/kg body weight alpha 1-AT in addition to their regular medication. The progression of the disease was assessed by repeated lung function measurements, particularly the decline in forced expiratory volume in 1 second (delta FEV1). 443 patients with alpha 1-AT deficiency tolerated augmentation therapy well with few adverse reactions. The delta FEV1 in 287 patients with available follow-up data was 57.1 +/- 31.1 ml per year. Stratified for baseline FEV1, the decline was 35.6 +/- 21.3 ml in the 108 patients with an initial FEV1 < 30% and 64.0 +/- 26.4 ml in the 164 with 30% < FEV1 < or = 65% of predicted normal (p = 0.0008). The remaining 15 patients had an initial FEV1 > 65%. Long-term treatment with i.v. alpha 1-antitrypsin in patients with severe alpha 1-Pi deficiency is feasible and safe. The decline in forced expiratory volume in one second is related to the initial forced expiratory volume in one second as in alpha 1-antitrypsin deficient patients not receiving augmentation therapy.     

Treatment of subdural effusion with hydrocephalus after ruptured intracranial aneurysm clipping

This study examined the role of cysteine proteinases and their inhibitor in the development of emphysema in comparison with neutrophil elastase (NE) complexed with alpha1-protease inhibitor (NE-alpha1-PI), which was previously demonstrated to be increased in bronchoalveolar lavage (BAL) fluid from subjects with subclinical emphysema. Eight nonsmokers and 31 current smokers with (n=17) and without (n=14) emphysema, as evidenced by lung computed tomographic scans, were studied. The concentrations of immunologically detected cathepsin L and cystatin C, but not cathepsin B, were significantly increased in BAL fluid from the smokers with emphysema compared with those without emphysema, although the activity of cathepsin L, measured using a synthetic substrate and cathepsin L, released from cultured alveolar macrophages at 24 h, did not show any significant difference between the two groups. When comparison was made only for the subjects aged <60 yrs, the difference between the two groups disappeared for cathepsin L, but remained for NE-alpha1-PI. There was no significant correlation between the level of cathepsin L and that of NE-alpha1-PI in BAL fluid from the subjects with emphysema. In conclusion, increased levels of cathepsin L and cystatin C were demonstrated in bronchoalveolar lavage fluid from subjects with subclinical emphysema. However, the roles of cathepsin L and neutrophil elastase in the development of emphysema may vary between subjects and between the young and the old.     

Oxidative inactivation of alpha 1-proteinase inhibitor by alveolar epithelial type II cells

The aim of this work was to evaluate the ability of guinea pig alveolar epithelial type II cells to generate significant amounts of reactive oxygen species to inactivate alpha 1-proteinase inhibitor (alpha 1-PI). Inactivation of alpha 1-PI was evaluated by its inhibitory activity against porcine pancreatic elastase and was expressed as a percentage. The same experiments were performed in parallel with alveolar macrophages (AM) obtained from the same animals and with MRC-5 fibroblasts. Both type II cells and AM released significant amounts of hydrogen peroxide and superoxide, whereas the fibroblasts did not. Unstimulated type II cells (0.5 +/- 2%), AM (1.2 +/- 1.5%), and fibroblasts (0.5 +/- 0.5%) were unable to inactivate alpha 1-PI. Addition of phorbol myristate acetate did not increase their ability to inactivate alpha 1-PI. In contrast, type II cells (79.7 +/- 7%) and AM (80.1 +/- 8%) dramatically inactivated alpha 1-PI in the presence of myeloperoxidase (25 mU/ml), whereas fibroblasts did not. Addition of catalase to the reaction significantly prevented the inactivation of alpha 1-PI. Western blot analysis of alpha 1-PI did not reveal a significant proteolysis of alpha 1-PI, which supports the hypothesis that, in the presence of neutrophil-derived myeloperoxidase, type II cells may oxidatively inactivate alpha 1-PI.     

Pathophysiology and treatment of alpha 1-antitrypsin deficiency

The pathophysiology of alpha 1-antitrypsin (AAT) deficiency and the use of alpha 1-proteinase inhibitor therapy in the management of emphysema caused by AAT deficiency are described. AAT deficiency is the most common genetic cause of liver disease in children and emphysema in adults. However, not all patients with AAT deficiency develop hepatic or pulmonary involvement. Changes in the composition of the AAT molecule have been associated with AAT dysfunction in liver disease, whereas lung disease occurs when AAT concentrations are reduced. A definitive diagnosis can be made through serum AAT phenotype determination. Therapy for liver disease induced by AAT deficiency consists of supportive measures. Therapy for pulmonary disease due to AAT deficiency includes AAT augmentation therapy along with supportive measures. The available product, alpha 1-proteinase inhibitor, is derived from fractionated plasma and has similar biological activity to native serum AAT. Clinical trials have demonstrated a positive effect on serum and lung concentrations of AAT with few adverse events. Two recombinant forms of AAT have also been developed; however, few trials have been published evaluating their safety and efficacy in AAT-deficient patients. Many questions remain unanswered concerning AAT deficiency and replacement therapy. AAT augmentation therapy appears to reduce the progression of emphysema in some AAT-deficient patients.     

Host response to initial and challenge infections, following treatment, of Gyrodactylus bullatarudis and G. turnbulli (Monogenea) on the guppy (Poecilia reticulata)

Patients homozygous for the Z allele of alpha-1-antitrypsin (alpha 1AT) have very low serum levels and are predisposed to emphysema. There have also been reports of emphysema being associated with the heterozygous phenotype FZ. To investigate whether F alpha 1AT was dysfunctional, the inhibitory activity of F alpha 1AT against human neutrophil elastase (HNE) was compared with that of common alpha 1AT phenotypes. Time-dependent inhibition of HNE by alpha 1AT was used to calculate the association rate constant (k assoc) for M, MZ, FM, FZ, F (partially purified from FZ or FS), Z and S alpha 1AT phenotypes in human sera. The results for k assoc at 25 degrees C were 9.1 (SD 0.9), 9.7 (SD 0.9), 8.0 (SD 0.8), 4.0 (SD 0.4), 4.2 (SD 0.8), 5.1 (SD 0.6) and 8.6 (SD 0.6) x 10(6) M-1s-1 respectively. F was found to have reduced activity much like that of Z, the alpha 1AT most commonly associated with emphysema. MZ (low risk for disease) and FZ heterozygotes had similar intermediate alpha 1AT levels. However the in vivo inhibition time for FZ was almost three times longer than for MZ, indicating greater exposure to proteolytic damage from free elastase for FZ than MZ individuals. In conclusion, F alpha 1AT is expressed in serum at low normal levels but is dysfunctional in its ability to inhibit HNE. Individuals who coinherit the F and a deficiency allele such as Z or Null, are likely to have a high risk for the development of emphysema. The disease risk for F homozygotes remains to be determined.     

Apparent total alpha1-antitrypsin deficiency: report of a case

A 29-year-old female, with chronic renal failure and chronic bilateral emphysema, was admitted with severe uremia and septicemia secondary to multiple abscesses in the right kidney. Her condition improved after right nephrectomy. Pulmonary function studies showed marked obstructive and restrictive lung disease consistent witht the diagnosis of primary emphysema. On biochemical and histological examination, the liver was found to be normal. Alpha1-antitrypsin could not be demonstrated in the patient's serum at normal pH by any of the known techniques, but protein molecules with alpha1-antitrypsin antigencity were found at pH 4.8; this suggests a pH-dependent structural difference in alpha1-antitrypsin protein. Starch gel electrophoresis gave a multibanding pattern not previously described. A new form of apparent total alpha-1-antitrypsin deficiency is postulated.     

Involvement of protease inhibitors in staphylokinase-induced fibrin-specific fibrinolysis

We compared the fibrinolytic properties of recombinant staphylokinase (SAK), a fibrin-specific plasminogen activator, with those of streptokinase and tissue-type plasminogen activator (t-PA) by means of the amidolytic method. We also investigated the involvement of alpha 2-macroglobulin, C1-inactivator and alpha 1-antitrypsin in SAK-induced fibrin-specific fibrinolysis. Both SAK and t-PA activated plasminogen efficiently in the presence of fibrin in human plasma. Although t-PA activated plasminogen dependently on fibrin in the reconstituted plasma system, SAK activated plasminogen independently of fibrin without alpha 2-plasmin inhibitor (alpha 2-antiplasmin, alpha 2-PI). These findings suggest that fibrin and alpha 2-PI play important roles in plasminogen activation by SAK but not by t-PA. Furthermore, protease inhibitors such as alpha 2-PI, alpha 2-macroglobulin, C1-inactivator and alpha 1-antitrypsin inhibited plasminogen activation by SAK and the inhibitory actions of these protease inhibitors disappeared in the presence of fibrin. This shows that alpha 2-macroglobulin, C1-inactivator and alpha 1-antitrypsin, other than alpha 2-PI, contribute to the fibrin-specificity of SAK.     

Determination of inflammatory bowel disease activity by breath pentane analysis

Polymorphonuclear neutrophil (PMN) stimulation and degranulation can be mediated by the cytokines and by complement activation. The aim of the present study was to measure TNF alpha, IL-1 alpha, IL-6 and C3d in relation to postoperative increase in lactoferrin and elastase alpha-1-proteinase inhibitor (E alpha-1-PI) levels. Eleven patients undergoing thoracic surgery took part in the study. Blood leucocytes, E alpha-1-PI, lactoferrin and C3d were measured preoperatively, at the end of surgery and postoperatively, at 4 h and on day 1, 2, 3 and 5. TNF alpha, IL-1 alpha and IL-6 were measured preoperatively, at the end of surgery and postoperatively, at 4 h, and on days 1 and 5. The leucocyte count, lactoferrin and E alpha-1-PI levels increased significantly postoperatively (P < 0.01). There was no significant change in C3d values. Plasma IL-6 levels were unchanged in the postoperative period. Plasma TNF alpha and IL-1 alpha were detectable at low levels in only two and four patients, respectively. Conclusion: The postoperative increase in blood levels of PMN lactoferrin and E alpha-1-PI complexes observed in the present study was not accompanied by complement activation, or increased blood levels of IL-6.     

Effect of polynucleotides on the inhibition of neutrophil elastase by mucus proteinase inhibitor and alpha 1-proteinase inhibitor

DNA released from neutrophils at sites of inflammation may modulate tissue proteolysis. We used tRNA and synthetic polynucleotides as models of DNA to study the influence of polynucleotides on the inhibition of neutrophil elastase by its endogenous inhibitors alpha1-proteinase inhibitor (alpha1-PI) and mucus proteinase inhibitor (MPI). Affinity chromatography showed that polynucleotides form electrostatic complexes with elastase and MPI but not with alpha1-PI, the highest affinity being for MPI. The tight-binding partial inhibition of elastase by polynucleotides was used to calculate the Kd of the elastase-polynucleotide complexes which ranged from 4 microM to 21 nM. One mole of tRNA was able to bind 9 mol of elastase. Polydeoxycytosine and tRNA significantly impaired the reversible inhibition of elastase by MPI: they moderately increased the rate of enzyme-inhibitor association, strongly enhanced the rate of complex dissociation, and lowered the enzyme-inhibitor affinity by factors of 34 and 134, respectively. The two polynucleotides also decreased the rate of the irreversible inhibition of elastase by alpha1-PI by factors of 30 and 3, respectively. Polynucleotides also changed the mechanism of inhibition of elastase by the two inhibitors from a one-step inhibition reaction to a two-step binding mechanism. Our data may help explain why proteolysis may occur at sites of inflammation despite the presence of active proteinase inhibitors.     

Drug-induced lupus erythematosus

alpha 1-Antitrypsin (AT) is the principal serum inhibitor of proteolytic enzymes such as neutrophil elastase. AT can exist as over 90 different genetically determined variants known as the Pi system; the three most important variants are type M (90% of population) and types S and Z, two of the commoner abnormal variants. Homozygotes of type Z have a severe reduction in the serum AT concentration and may develop pulmonary emphysema or hepatic cirrhosis. Heterozygotes of type SZ have a less severe reduction in serum AT concentration and the association with clinical disease is less clear. The S and Z variants are found mainly among those of European stock. The gene frequency for Pi type Z is highest on the north-western seaboard of the continent and the mutation seems likely to have arisen in southern Scandinavia. The distribution of type S is quite different; the gene frequency is highest in the Iberian peninsula and the mutation is likely to have arisen in that region. A population survey for determining the number of type Z homozygotes in a given community is important for planning purposes now that AT replacement therapy is potentially available.     

Radiologic emphysema morphology is associated with outcome after surgical lung volume reduction

BACKGROUND: Lung volume reduction surgery is known to alleviate dyspnea and to improve pulmonary function, performance in daily activity, and quality of life in selected patients with severe pulmonary emphysema. We investigated the role of radiologically assessed emphysema morphology on functional outcome after a lung volume reduction operation. METHODS: The preoperative chest computed tomograms in 50 consecutive patients who had undergone surgical lung volume reduction were retrospectively reviewed by 6 physicians blinded to the clinical outcome. Emphysema morphology was determined according to a simplified classification (ie, homogeneous, moderately heterogeneous, and markedly heterogeneous; lobe predominance). We studied the impact of these morphologic aspects on functional outcome at 3 months. RESULTS: We found a fair interobserver agreement applying our classification system. Functional improvement after surgical lung volume reduction was best in markedly heterogeneous emphysema with an increase in forced expiratory volume in 1 second of 81% +/- 17% (mean +/- standard error, n = 17) compared with 44% +/- 10% (n = 16) for intermediately heterogeneous emphysema. But also in patients with homogeneous emphysema clinical relevant improvement of function could be observed (increase in forced expiratory volume in 1 second = 34% +/- 6%; n = 17). CONCLUSIONS: The morphologic type of emphysema, assessed by a simplified surgically oriented classification, is an important predictor of surgical outcome. Lung volume reduction surgery may also improve dyspnea and lung function in homogeneous emphysema.     

Inhibition of anaphylactic reaction in guinea pigs by antibodies to fragments of Fc from autologous IgG

The effect of antibodies to Fc subfragments of guinea pig IgG on the anaphylactic reaction in guinea pigs has been studied. Control animals were immunized with guinea pig IgG and Fab, human IgG and albumin. All animals with antibodies to fragments of autologous Fc survived challenge with horse serum, whereas the control animals died in anaphylactic shock.     

Current issues in the management of chronic obstructive pulmonary diseases

Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality, especially among smokers. Many guidelines that have recently been issued emphasize that COPD is not inaccessible to therapeutic measures: although few interventions are capable of affecting its natural history (i.e. smoking cessation and, in patients with severe resting hypoxaemia, oxygen therapy), several others have a demonstrated effect on symptoms and, thereby, quality of life. The effects of inhaled corticosteroids, and alpha 1-antitrypsin replacement therapy in emphysema due to alpha 1-antitrypsin deficiency are currently being studied. When there is a marked increase in mucus production, chest physiotherapy using controlled expiration and directed cough may be useful. Inhaled bronchodilators are frequently effective on dyspnoea, anticholinergic agents being more suitable for continuous symptoms. Rehabilitation, which includes education and psychosocial care, chest physiotherapy, nutritional care and exercise training, also improves quality of life. When there is persistent severe alveolar hypoventilation despite oxygen therapy, long-term mechanical ventilation may be considered. Surgical options in the treatment of emphysema include resection of giant bullae and lung volume reduction surgery. Lung transplantation should be proposed only in patients with end-stage disease, the difficulty here being to define what 'end-stage' means. Finally, all preventive and some therapeutic interventions are likely to be more effective early in the course of the disease. Thus, efforts should be made to detect airways obstruction early in subjects at risk, such as smokers.     

High levels of elastolytic activity in bronchoalveolar lavage fluid from a patient with idiopathic interstitial pneumonia]

A 63-year-old female with acure exacerbution of idiopathic interstitial pneumonia (IIP) showed high levels of elastolytic activity in bronchoalveolar lavage fluid (BALF). She was admitted to our hospital with progressive dyspnea. Arterial blood gas analysis and pulmonary function tests were abnormal. Examination of the bronchoalveolar lavage fluid revealed an increased numbers of neutrophils. Despite the administration of corticosteroids, the patient died of respiratory failure. A high level of elastolytic activity was present in the BALF. Western immunoblot analysis, using an anti-alpha 1-protease inhibitor (PI) antibody, revealed a truncated alpha 1-PI in the BALF. These findings suggest that an imbalance between protease and PI in the lower respiratory tract contribute to lung tissue damage in patients with IIP.     

Hyperplasia of pulmonary neuroendocrine cells in a case of childhood pulmonary emphysema

Pulmonary emphysema is very uncommon in children in the first decade of life. The few cases documented in the literature were all due to alpha1-antitrypsin deficiency. We present the case of a 6-year-old white boy with chronic cough and dyspnea on exertion. Lung biopsy showed panacinar type emphysema with patent airways and diffuse hyperplasia of pulmonary neuroendocrine cells revealed after immunostaining for bombesin, a peptide produced by these cells. We speculate that idiopathic diffuse hyperplasia of bombesin-producing pulmonary neuroendocrine cells may contribute to the pathogenesis of unusual COPD in childhood.     

Bullous sarcoidosis: a report of three cases

Three cases of pulmonary sarcoidosis presented as bullous emphysema with severe airflow obstruction, and the diagnosis of sarcoidosis was unsuspected for at least 2 years. Potential mechanisms of bullous emphysema from sarcoidosis are discussed. The physician should suspect sarcoidosis as the cause of bullous emphysema when young patients who have smoked relatively few pack-years present with emphysema or severe airflow obstruction. Additional clues are the presence of mediastinal adenopathy on a chest radiograph or a CT scan and a history consistent with extrapulmonary sarcoidosis.     

The "cyclic" regimen of low-dose doxycycline for adult periodontitis: a preliminary study

Specially-formulated low-dose doxycycline (LDD) regimens have been found to reduce collagenase activity in the gingival tissues and crevicular fluid (GCF) of adult periodontitis subjects in short-term studies. In the current, double-blind, placebo-controlled study, adult periodontitis patients were administered for 6 months a "cyclical" regimen of either LDD or placebo capsules; and various clinical parameters of periodontal disease severity, and both collagenase activity and degradation of the serum protein, alpha 1-PI, in the GCF were measured at different time periods. No significant differences between the LDD- and placebo-treated groups were observed for plaque index and gingival index. However, attachment levels, probing depth, and GCF collagenase activity and alpha 1-PI degradation were all beneficially and significantly (P < 0.05) affected by the drug regimen. We propose: 1) that LDD inhibits tissue destruction in the absence of either antimicrobial or significant anti-inflammatory efficacy; and 2) that long-term LDD could be a useful adjunct to instrumentation therapy in the management of the adult periodontitis patient.     

Experimental emphysema

This animal model of emphysema exhibits the same abnormalities in respiratory mechanics as those seen in human emphysema. The histologic and radiographic findings also closely resemble changes of panacinar disease. Moreover, the progressive hypoxemia preceding hypercarbia also parallels the clinical course seen in human disease. Drawbacks of this model include the long time period required to develop significant changes and the cost of maintaining the animals for such a time period. Large cystic areas were not noted in our animals and one would have to turn to another model to address the problem of giant bullous emphysema. There is no ideal animal model of pulmonary emphysema, and the usefulness of an experimental model should be judged on how well it answers the specific questions. Significant information has been obtained using various animal models of emphysema in lung transplantation, diaphragmatic function, pulmonary hemodynamics, and in several other areas. The dog appears to be a suitable model for thoracic surgical research on emphysema.     

The assessment of the severity of pulmonary edema by computed tomography. A comparison between high-resolution computed tomography, objective evaluation with density masks and functional tests

The results of high-resolution computed tomography (HRCT) were correlated with those of pulmonary function tests, chest films and CT expiratory density mask values in the evaluation of pulmonary emphysema in 33 symptomatic subjects. Emphysema was quantitated with both subjective and objective measurements. Conventional chest films were useful to diagnose severe emphysema but its actual extent was more reliably evaluated with CT scoring systems. HRCT and density mask correlated well with function tests, but the former method exhibited stronger correlation with carbon monoxide diffusion capacity. The opposite was true for hyperinflation and expiratory obstruction variables. Subjective CT estimates, which are quick and easy to perform, were seen to correspond more specifically to the pathophysiologic derangement and should therefore be used to evaluate the anatomic extent of disease. The functional severity of emphysema correlated only with the overall extent of disease and not with its regional distribution in the upper or lower lungs. Finally, in 4 cases (12.1%) with low CT scores, FEV1 was reduced but diffusion capacity values were normal. In one of these patients HRCT showed signs of bronchiolitis. In fact, small airway disease might be a more critical factor in determining functional impairment than the actual anatomical emphysema.