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Biomedical subjects

E C Lucey

Publications and source records attributed to E C Lucey.

At least 19 recordsLinked to original sources
PubMed1992

Covalently linking a peptidyl carbamate elastase inhibitor to a hydrophilic polymer increases its effectiveness in preventing emphysema and secretory cell metaplasia in the hamster.

A peptidyl carbamate, p-nitrophenyl N-(succinyl-L-alanyl-L-alanyl-L-prolyl-methyl)-N-isopropylcarbamate++ + (PCI) was tested for its ability to inhibit the elastolytic activity of human neutrophil elastase (HNE) and to prevent HNE-induced emphysema and secretory cell metaplasia in the hamster. In vitro, 50% of the elastolytic activity of 10 micrograms of HNE was inhibited by 0.9 micrograms of PCI, a molar ratio of PCI to HNE of 4.5. Bronchoalveolar lavage of hamsters receiving PCI intratracheally showed a rapid decrease in HNE inhibitory activity (4 min for 50% decrease), suggesting rapid clearance, binding, or inactivation of the PCI. Instillation of 300 micrograms of HNE combined with 100, 500, or 3,000 micrograms PCI, a 16-, 83-, and 503-fold molar excess of PCI, respectively (molar ratios of 17, 84, and 504), suppressed HNE-induced lung hemorrhage, but it did not moderate HNE-induced emphysema despite the large molar excess of inhibitor. When PCI was covalently bound to a linear hydrophilic polymer of alpha,beta-poly[N(2-hydroxyethyl)-D,L-aspartamide], producing a polymer-bound carbamate inhibitor (PPCI) of HNE, the time for a 50% decrease of PPCI functional activity from the hamster lung lavage was 421 min. Instillation of 100 micrograms of PPCI 1 h before instillation of 300 micrograms HNE resulted in significant amelioration of emphysema; 900 micrograms of PPCI was required to obtain amelioration of bronchial secretory cell metaplasia. The larger dose of PPCI also provided significant amelioration of emphysema when the interval between PPCI and HNE administration was 8 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Putative role of neutrophil elastase in the pathogenesis of emphysema.

Emphysema in humans takes several different forms: centrilobular, panacinar, paraseptal, and airspace enlargement with fibrosis. The varying morphologic and background features of these forms of emphysema suggest that they differ in pathogenesis. Elastic fiber rupture and fraying are a feature of emphysema. Experimental emphysema may be induced by human neutrophil elastase and other elastolytic enzymes but not by nonelastolytic proteases. Disruption of elastic fibers also appears to be the underlying feature of lathyrogen-induced airspace enlargement and of the emphysema in the blotchy mouse. However, there is no evidence of elastic fiber destruction in cadmium-induced airspace enlargement with fibrosis or in emphysema associated with hyperoxia or severe starvation. Thus, elastic fiber disruption is not common to all forms of experimental emphysema. We posit that airspace enlargement may be a stereotyped response of the lungs to different injuries. Emphysema can be induced in experimental animals by repeated induction of pulmonary neutrophilia. However, the evidence for involvement of neutrophil elastase in human emphysema is not clear: there are studies using a variety of approaches that weigh on both sides of the question. There is also in vitro evidence that alveolar macrophages can degrade elastin or elastic fibers with which they are in contact by means of a metalloelastase or the cooperative action of plasminogen activator and an acid cysteine protease. We conclude that the pathogenesis of emphysema is complex. Neutrophil elastase likely plays a major role in the development of some forms of emphysema, but our understanding of the interactions between the alveolar walls and neutrophils is still fragmentary.

Animals↗
PubMed1991

Measurement of urinary desmosine by isotope dilution and high performance liquid chromatography. Correlation between elastase-induced air-space enlargement in the hamster and elevation of urinary desmosine.

The accuracy of methods employed to measure the elastin-specific crosslinks, desmosine (DES) and isodesmosine (IDES), has been called into question because contaminants in the urine may cause elevated values. In the present study urine samples were spiked with a known amount of [14C]DES and refluxed in 6 N HCl. Sephadex G-15 chromatography of the hydrolyzed urine employed to remove contaminants. DES and IDES were quantified by high performance liquid chromatography (HPLC) as well as by amino acid analysis. The amount of isotope recovered was used to determine losses during the overall procedure and the isotope dilution to calculate the amounts of endogenous DES and IDES originally present in the urine. Because similar values were obtained by both methods, the more rapid HPLC method was used for all succeeding analyses. In one experiment, the DES amounts in urine collected from hamsters for 3 days after intratracheal treatment with human neutrophil elastase (300 micrograms) or porcine pancreatic elastase (300 micrograms) were 0.212 +/- 0.012 (mean +/- SEM, two measurements on a single pool) and 0.816 +/- 0.005 (two measurements) microgram per hamster per day, respectively. Urine from control hamsters had a mean value of 0.074 +/- 0.008 (eight measurements) microgram per hamster per day. The HNE- and PPE-treated hamsters had mean linear intercept values of 119 and 159% of control values, respectively, giving a positive correlation between increase in airspace size and elevation of urinary DES.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Induction and exacerbation of emphysema in hamsters with human neutrophil elastase inactivated reversibly by a peptide boronic acid.

In solution, MeO-Suc-Ala-Ala-Pro-D,L-boro-Val pinacol ester (Boroval) is a highly effective but reversible inhibitor of both porcine pancreatic elastase and human neutrophil elastase (HNE) (50% inhibition with a 1.5 M ratio of Boroval to elastase). Boroval has been shown to prevent porcine-pancreatic-elastase-induced emphysema in hamsters. But with HNE-induced emphysema in hamsters, pretreatment with as much as a 170-fold M excess of Boroval, given intratracheally 1 h before 0.3 mg HNE, did not prevent emphysema. Indeed, lung volumes were larger after Boroval pretreatment than after HNE alone. Emphysema was also induced by instilling HNE that had been mixed with and inactivated by a 41-fold M excess of Boroval (a molar ratio of 42). When 0.25 or 0.5 mg of HNE were given mixed with a 41-fold M excess of Boroval, the emphysema was much more severe with the 0.5 mg dose. Two hours after instillation of 0.3 mg HNE inactivated with a 34-fold M excess of Boroval, bronchoalveolar lavage contained elastolytic activity but no evidence of hemorrhage. In contrast, hemorrhage was severe in hamsters that had been instilled with 0.3 mg HNE alone. We conclude that Boroval can enhance HNE-induced emphysema. We postulate that Boroval suppresses HNE-induced hemorrhage and the resultant influx of plasma protease inhibitors; the HNE-Boroval complex is transported into the alveolar interstitium, followed by dissociation of the inhibitor from the active site of HNE. Because of its small size, free Boroval is rapidly cleared, and the reactivated HNE attacks elastic fibers, giving rise to emphysema.

Animals↗
PubMed1990

Cell kinetics of normal adult hamster bronchial epithelium in the steady state.

To establish the progenitor role of bronchial epithelial cells in the steady state, we undertook a quantitative autoradiographic study in normal hamsters. Groups of 7 hamsters were killed 1 h and 1, 2, 3, 4, 7, and 14 d after an intraperitoneal injection of [3H]thymidine (2 microCi/g body wt). Autoradiograms were prepared from 861 Epon sections, 2 microns thick, of left intrapulmonary hilar bronchi. Epithelial cells were classified into 1 of 7 categories: basal-1 (B1) and basal-2 (B2), depending on nuclear height; secretory cells denoted as S1 with zero to 4 granules, S2 with 5 or more granules with intervening cytoplasm, and S3 with abundant granules completely filling the cytoplasm; ciliated (C); and indeterminate (IN). Mean silver grain counts decreased significantly over time only for B1 cells (P less than 0.05), with a cell cycle time of 20.6 d and a DNA synthetic time of 7.5 h. Labeled cells, 1 h after thymidine injection, comprised 30.5% S1, 27.8% B1, 22.8% B2, 6.8% IN, 6.4% S2, 5.7% C, and 0% S3 cells. Labeling indices of individual cell categories (LIc), at 1 h after labeling, were highest for B1 followed by B2 cells, reflecting their proliferative intensity. Labeling index of all epithelial cells combined did not change with time, indicating that there was no major cell death or label dilution. The LIc decreased significantly over time only for B1 and B2 cells (P less than 0.001 and P less than 0.002, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Lectin cytochemistry reveals differences between hamster trachea and bronchus in the composition of epithelial surface glycoconjugates and in the response of secretory cells to neutrophil elastase.

Hamsters exposed to an intratracheal instillation of human neutrophil elastase (HNE) accumulate an abnormally high number of secretory granules in bronchial but not tracheal epithelial cells. We employed lectin cytochemistry to investigate possible differences in the epithelial cell surface glycoconjugate layer in trachea compared to bronchus which might explain the regional dissimilarity in response to HNE. Portions of glutaraldehyde-fixed trachea and bronchi were incubated in one of several ferritin-labeled lectins prior to embedding for transmission electron microscopy. Lectins from Ricinus communis, Helix pomatia, and Triticum vulgaris bound to the surface of tracheal secretory cells in moderate to profuse amounts, while most bronchial secretory cells showed little or no label with these lectins. Gold-labeled Helix pomatia agglutinin (HPA), a lectin specific for secretory cells, showed a decrease in surface binding to all tracheal secretory cell types within 2 h of HNE instillation, compared to saline controls. In contrast, the majority of bronchial secretory cells showed an HNE-induced increase in surface label from extremely low levels in saline controls. The low levels of lectin binding to bronchial cells, in contrast to the trachea, may indicate the lack of a protective surface glycoconjugate coat, thus explaining the vulnerability of these cells to HNE. The rise in number of accessible HPA binding sites on the surface of bronchial secretory cells exposed to HNE may represent an important event in the pathologic accumulation of secretory granules by these cells.

Animals↗
PubMed1990

The specific treatment of emphysema.

Cigarette smoking is the major risk factor for development of emphysema. Many people are unable to stop smoking despite skilled support. The elastase-antielastase imbalance hypothesis for the pathogenesis of emphysema suggests that treatment with a supplemental elastase inhibitor might prevent development of emphysema in susceptible people. Many elastase inhibitors have been developed. Poorly soluble inhibitors do not prevent emphysema when tested in an animal model of elastase-induced emphysema. Irreversible inhibitors are effective in a dose-response manner. Reversible but tight-binding large molecular weight inhibitors, which clear slowly from the lungs, are effective in vivo. Small molecular weight, reversible inhibitors prevent haemorrhage after human neutrophil elastase instillation into the lungs but may potentiate emphysema. Only 15% of long-term smokers are susceptible to the development of emphysema. Susceptible smokers can be identified by the development of airflow obstruction. An outcome study of efficacy of elastase inhibitor therapy would be prohibitively expensive. However, a study of the process of development of elastase-induced emphysema is feasible. Measurement of alterations in elastase load of the lungs, elastase derived fibrinopeptides, circulating elastin peptides and urinary desmosines could be used for this purpose.

Animals↗
PubMed1990

Recombinant human secretory leukocyte-protease inhibitor: in vitro properties, and amelioration of human neutrophil elastase-induced emphysema and secretory cell metaplasia in the hamster.

Studies were undertaken to evaluate the in vitro properties of recombinant human secretory leukocyte-protease inhibitor (rSLPI) that had been made in Escherichia coli in an inactive form and refolded, and to determine whether emphysema and bronchial secretory cell metaplasia, induced in hamsters by intratracheal treatment with human neutrophil elastase (HNE), could be amelio-rated by prior intratracheal instillation of rSLPI. Chromatographic studies indicated that 3H-rSLPI formed a 1:1 complex with HNE. Blockage of the active site of HNE by a covalently bound tetrapeptide chloromethyl ketone reduced complex formation with 3H-rSLPI by more than 98%. Incubation of 3H-rSLPI-HNE complex with alpha 1-protease inhibitor for 3 hours at 37 degrees C decreased the amount of complex compared with incubation in the presence of bovine serum albumin (70% vs 27% dissociated). The calculated dissociation rate constant was 1.1 x 10(-4) sec-1, indicating a 1.8 hour dissociation half-life. Dissociated 3H-rSLPI retained its ability to recombine with HNE. rSLPI was as effective at inhibiting HNE released from stimulated neutrophils as 3H-rSLPI was at inhibiting purified HNE. Intratracheal pretreatment of hamsters with 3000 micrograms of rSLPI as long as 8 hours before the intratracheal instillation of 250 micrograms of HNE, resulted in significant protection against induction of emphysema and secretory cell metaplasia. One and 4 hours after instillation of rSLPI, 59% and 44%, respectively, of the initial functional activity was recovered in lung lavage supernatant, indicating a half-life of approximately 2 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Alpha 1-protease inhibitor moderates human neutrophil elastase-induced emphysema and secretory cell metaplasia in hamsters.

A study was undertaken to determine whether emphysema and airway secretory cell metaplasia, induced in hamsters by intratracheal treatment with human neutrophil elastase (HNE), could be moderated by pretreatment with human alpha 1-protease inhibitor (API). API (4.9 mg) was given intratracheally to hamsters 1 h before 0.3 mg HNE. Eight weeks later, lung volumes and pressure-volume relationships were measured in the anaesthetized animals. Mean linear intercepts and secretory cell indices were measured in lung sections. API given 1 h before HNE moderated the development of bronchial secretory cell metaplasia. The severity of emphysema was reduced by 75%. Clearance studies indicated that 80% of the functional activity of instilled API could be lavaged from the lungs after 1 h, indicating a 4 h half-life in the lavageable compartment of the lungs. We calculate that for 50% protection from emphysema the molar ratio of lavageable API to HNE at the time of HNE instillation was 4.8 as compared with 0.78 for 50% inhibition of elastolytic activity in vitro, indicating that API is only 16% as efficient in vivo as compared with its in vitro HNE inhibitory effectiveness. Nevertheless, we conclude that human API given intratracheally is efficacious against HNE-induced emphysema and secretory cell metaplasia.

Animals↗
PubMed1989

Regional difference in airway epithelial response to neutrophil elastase: tracheal secretory cells discharge and recover in hamsters that develop bronchial secretory-cell metaplasia.

Human neutrophil elastase (HNE) causes secretory granule discharge and conversion of many Clara cells to mucous cells in hamster bronchi. We investigated whether the trachea responds to HNE in a similar manner because of its abundance of Clara cells. By light microscopy, the tracheal epithelium of animals exposed to a single intratracheal injection of HNE was normal at 21 days, although bronchial secretory-cell metaplasia (SCM) was present. An ultrastructural differential cell count showed no increase in the proportion of granulated secretory cells in HNE-treated animals at 8 and 21 days postinjection compared to saline or untreated controls. At 2 h, the percentage of granulated secretory cells was lower and that of granulated secretory cells was higher in HNE-treated animals than in controls. The HNE-treated animals had fewer secretory granules per cell profile and more surface undulation than controls. By 1 day, the differential cell count and number of granules per cell profile were normal. Saline did not affect the differential cell count or granule number at any time. Ultrastructural study of untreated trachea disclosed the same three types of Clara cell that are found in the bronchus, but their frequencies, with one exception, are significantly different in the two regions. We conclude that HNE acts as a secretagogue in both trachea and bronchus but that an amount of enzyme sufficient to cause bronchial SCM does not induce a similar lesion in trachea. Heterogeneity of Clara cell types in hamster airways may explain the regional variation in secretory-cell modulation by HNE.

Animals↗
PubMed1989

Amelioration of human neutrophil elastase-induced emphysema in hamsters by pretreatment with an oligopeptide chloromethyl ketone.

Human neutrophils are a likely source of elastase in the pathogenesis of human pulmonary emphysema. A study was undertaken to determine whether emphysema, induced in hamsters by intratracheal treatment with human neutrophil elastase (HNE), could be ameliorated by intratracheal instillation of succinyl-alanyl-alanyl-prolyl-valine-chloromethyl ketone (CMK). One mg of CMK was given to hamsters 1 h before 300 or 360 micrograms HNE or 1 h or 4 h after 360 micrograms HNE. The animals were studied eight weeks after treatment. The CMK given 4 h after HNE did not ameliorate the emphysema. The CMK given 1 h before HNE, ameliorated the development of emphysema but not bronchial secretory cell metaplasia. A molar ratio of instilled CMK to HNE of 128 was required for 50% in vivo effectiveness in ameliorating emphysema. Clearance studies indicated that 6.9% of the instilled CMK could be lavaged from the lungs 1 h after instillation. Therefore, an 8.9 to 1 molar ratio of lavageable CMK to HNE, at the time of HNE instillation, resulted in 50% protection. Using an in vitro assay with 3H-elastin as substrate, a 3 to 1 molar ratio of CMK to HNE was required to inhibit 50% of the elastolytic activity; 14% of the activity remained with an 18 to 1 molar ratio of CMK to HNE. Study of the in vivo effectiveness of anti-elastases, given as pretreatment in ameliorating HNE-induced emphysema and secretory cell metaplasia, is a reasonable bioassay, which may be used as a step in evaluating such agents for possible use in the prevention of human disease.

Animals↗
PubMed1988

Acid-induced secretory cell metaplasia in hamster bronchi.

Hamsters were exposed to an intratracheal instillation of 0.5 ml of 0.08 N nitric, hydrochloric, or sulfuric acid to determine their airway epithelial response. Three weeks after exposure, the left intrapulmonary bronchi in Alcian blue/PAS-stained paraffin sections were evaluated for the amount of secretory product in the airway epithelium as a measure of secretory cell metaplasia (SCM). Compared to saline-treated control animals, all three acids caused statistically significant SCM. In addition to the bronchial lesion, all three acids caused similar interstitial fibrosis, bronchiolectasis, and bronchiolization of alveoli that varied in individual animals from mild to severe. In a separate experiment to study the persistence of the SCM, hamsters treated with a single instillation of 0.1 N nitric acid showed significant SCM 3, 7, and 17 weeks after exposure. There was a high correlation (r = 0.96) between a subjective assessment of SCM and objective assessment using a digital image-analysis system. We conclude that protons induce SCM independently of the associated anion; the SCM persists at least 17 weeks. Sulfuric acid is an atmospheric pollutant and nitric acid may form locally on the mucosa of lungs exposed to nitrogen dioxide. These acids may contribute to the development or maintenance of the SCM seen in the conducting airways of humans with chronic obstructive pulmonary disease.

Animals↗
PubMed1988

Defenses of the hamster lung against human neutrophil and porcine pancreatic elastase.

Instillation of human neutrophil elastase (HNE) into hamster lungs produces milder emphysema but more pulmonary hemorrhage than an equivalent amount of porcine pancreatic elastase (PPE), whether equivalence is determined by elastolytic units or moles. We undertook a study of the mechanisms of these differences. 125I-HNE or 3H-PPE were instilled intratracheally into hamsters. The partitioning of radioactivity between bronchoalveolar lavage fluid (BAL) and lung tissue was similar for HNE and PPE as were the half-lives, 45 and 51 min, respectively, for uncomplexed, enzymatically active HNE and PPE. In BAL there was preferential binding and inactivation of HNE by the hamsters' alpha-1-protease inhibitor (a-1-PI) whereas PPE was preferentially bound by alpha-2-macroglobulin (a-2-M). This was also observed in vitro when HNE and PPE were incubated with plasma from untreated hamsters. Nevertheless, when the sum of the elastase binding capacity of a-1-PI and a-2-M was considered, hamster plasma had similar binding capacities for HNE and PPE. It is known that the enzymatic activity of elastases is inhibited by formation of a stable complex with a-1-PI. On the other hand, elastases bound to a-2-M are protected against a-1-PI inhibition but can free themselves by proteolysis and exhibit elastolytic activity. Preferential inactivation of HNE by a-1-PI may be one mechanism that accounts for the lesser emphysema-inducing potency of HNE than of PPE.

Animals↗
PubMed1988

Cadmium-chloride-induced air-space enlargement with interstitial pulmonary fibrosis is not associated with destruction of lung elastin. Implications for the pathogenesis of human emphysema.

To determine whether lung elastin is lost during the evolution of cadmium-induced air-space enlargement with pulmonary fibrosis, the lung elastin of 5- to 7-day-old golden Syrian hamster pups was radiolabeled by giving [3H]valine. At maturity, a single intratracheal instillation of 0.5 ml of 0.025% CdCl2 solution was given. Lung mechanics, histologic examination, and biochemistry were studied 5, 10, 21, 42, 105, and 180 days after the cadmium treatment. The animals developed fibrosis and air-space enlargement with decreased lung volumes, compliance, and forced expiratory flow; their functional residual capacity was increased. The total lung collagen and total lung elastin were increased, but there was no loss of radiolabel in lung elastin. We conclude that CdCl2-induced air-space enlargement with pulmonary fibrosis is not accompanied by loss of neonatally formed lung elastic fibers. We hypothesize that air-space enlargement with fibrosis represents a stereotyped response of the lung to fibrosing injuries, which we hypothesize is due to forces from more fibrotic and atelectatic areas causing overdistension of less abnormal air spaces. The air-space enlargement of fibrosing human diseases such as sarcoidosis and eosinophilic granuloma may have a similar basis. Evidence is reviewed that human centrilobular emphysema may be a form of focal air-space enlargement with interstitial fibrosis; there may be mechanisms in addition to elastase-antielastase imbalance that cause human emphysema.

Animals↗
PubMed1988

An 18-month study of the effects on hamster lungs of intratracheally administered human neutrophil elastase.

A study was made of the evolution of emphysema and airway injury induced in the lungs of male golden Syrian hamsters by a single intratracheal injection of 350 micrograms human neutrophil elastase (HNE). Saline control and HNE-treated groups of 8 animals were studied 1, 3, 6, 12, and 18 months posttreatment. HNE treatment caused a significant increase in all lung volumes and a significant decrease in maximum expiratory flows at all study times. The mean linear intercept (MLI) values of the left lung were significantly increased over control values. There was no progression with time in MLI values, lung volumes, or lung compliance. Secretory-cell metaplasia was present at 1 month and persisted throughout the study. The HNE-treated lungs showed clusters of ferric iron-containing macrophages in the terminal airspaces. The amount of iron in the lungs, determined morphometrically, was greatest at 1 month, was decreased by 6 months, and then did not change further to 18 months. At 18 months the amount of iron was still significantly above control amounts. We conclude that the airway and parenchymal lesions induced by HNE persist without progression for 18 months. Clearance of ferric iron, which was probably a result of the hemorrhage induced by HNE treatment, continued for 6 months with no evident subsequent clearance.

Animals↗
PubMed1987

An ultrastructural morphometric analysis of elastase-treated hamster bronchi shows discharge followed by progressive accumulation of secretory granules.

An ultrastructural morphometric analysis of bronchial secretory cells was carried out on hamsters treated intratracheally with 300 micrograms of human neutrophil elastase (HNE) in 0.5 ml saline, saline alone, or left untreated. Five to 6 animals were killed at 2 h and at 3, 8, and 16 days after treatment. Electron micrographs were prepared from the hilar region of the left main intrapulmonary airway; 125 +/- 16 (mean +/- SE) granulated secretory cells extending from basement membrane to lumen were analyzed for each group. The number (Ng) and area (Ag) of granular profiles per cell, the area of cell profiles (Ac), and the volume density of secretory granules per cell (Vv) were determined using an electronic image analyzer. There were significant decreases in Ng, mean Ag, and Vv in the 2-h HNE group when compared with the saline group. Values of Ng, mean Ag, and Vv were similar for HNE and saline groups at 3 days, but were significantly increased at 8 and 16 days. The Ac of HNE-treated groups was similar to their saline control groups at all time points except at 16 days when the HNE-treated group enlarged to double that of its saline control group. An ultrastructural differential cell count showed a decrease in frequency of granulated secretory cells at 2 h and an increase at 8 and 16 days; there was an inverse change in the frequency of nongranulated secretory cells at these times. The proportion of ciliated, preciliated, and indeterminate cells remained constant over time in all treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗