Recent Publications by CFE Educators

The neutrophil serine proteinases elastase and cathepsin G produce connective tissue injury, the extent of which depends on the balance between these enzymes and their inhibitors. The most important of these inhibitors is alpha 1-proteinase inhibitor, a member of a superfamily of homologous proteins known as serpins. Neutrophil cytosol inhibited the activities of human neutrophil elastase and cathepsin G in a dose-dependent fashion. To demonstrate formation of an enzyme-inhibitor complex, we combined 125I-elastase or 125I-cathepsin G with neutrophil cytosol or alpha 1-proteinase inhibitor and analyzed the products by polyacrylamide gel electrophoresis. Unbound elastase and cathepsin G each migrated to an apparent molecular weight of 25 kDa. In the presence of cytosol from neutrophils both radiolabeled enzymes migrated with a relative size of 68 kDa, whereas in the presence of alpha 1-proteinase inhibitor the relative size was 85 kDa. Enzyme-inhibitor complexes were stable in sodium dodecyl sulfate at 100 degrees C but were dissociated by hydrolysis in ammonium hydroxide (1.5 mol/L) at 37 degrees C. Formation of each complex was prevented by pretreatment of elastase or cathepsin G with diisopropylfluorophosphate, indicating that the inhibitor binds to the active site of the enzyme. Exposure of either alpha 1-proteinase inhibitor or neutrophil cytosol to the myeloperoxidase-H2O2-halide system prevented complex formation, suggesting the presence of an oxidizable amino acid at the binding site of the inhibitor. By electrophoretic analysis, the molecular weight of the cytosolic inhibitor was 43 kDa and neutrophils contained approximately 1 attomol of inhibitor per cell. The isoelectric points of the elastase and cathepsin G inhibitor were 5.5-5.9 and inhibitors of the two proteinases coeluted using size exclusion chromatography. These data demonstrate that human neutrophil cytosol contains a single serpinlike protein that inhibits elastase and cathepsin G. The inhibitor may be important in protecting the intracellular environment from proteolytic injury during degranulation.

Neutrophil migration into the airspaces of the lung is thought to contribute to the alveolar damage and subsequent fibrosis in idiopathic pulmonary fibrosis (IPF). Interleukin 8 (IL-8), a monocyte- and macrophage-derived cytokine, displays potent chemotactic and activating properties towards neutrophils and thus may contribute to the pathogenesis of IPF. The objective of this investigation was to quantify the spontaneous expression of IL-8 transcripts by alveolar macrophages from normal healthy volunteers and individuals with IPF. A quantitative assay employing reverse transcription of mRNA and the polymerase chain reaction was utilized. The level of IL-8 mRNA in alveolar macrophages was found to be significantly elevated in individuals with lone IPF or with lung fibrosis associated with connective tissue disorders compared to normal healthy controls. Moreover, the level of IL-8 mRNA in the 23 individuals with IPF correlated with the number of neutrophils per milliliter in their bronchoalveolar lavage (BAL) and with the degree of disease severity. In addition, the level of IL-8 protein in BAL was found to reflect the pattern of IL-8 mRNA expression by alveolar macrophages. These data suggest that IL-8 derived from alveolar macrophages may significantly contribute to neutrophil involvement in the pathogenesis of IPF.

Interstitial lung disease is characterized by interstitial inflammatory cell infiltration and fibrosis, a reduction in lung volumes, an increase in lung elastic recoil, and rapid shallow respirations. However, the alterations in lung volumes and elastic recoil as well as in breathing pattern are extremely variable, and the values are normal in a number of patients. In order to determine whether the effects of smoking could account for the variability in lung volumes and breathing pattern, we evaluated the elastic properties of the lung and the respiratory frequency at rest and during exercise in smokers and in nonsmokers with idiopathic pulmonary fibrosis (IPF) or with sarcoidosis. The volume-pressure curve in patients with IPF who smoked was positioned upwards and to the left when compared with that in nonsmokers. Conversely, the volume-pressure curve in patients with sarcoidosis who smoked was shifted downwards and to the right. In both conditions the respiratory rate while at rest and during exercise was greater in the group of patients who demonstrated the lower positioning of volume-pressure curves of the lungs (i.e., nonsmokers with IPF and smokers with sarcoidosis). We conclude that the impact of smoking may account, at least in part, for the variability in lung volume and volume-pressure characteristics of the lungs as well as the variability in respiratory rates in patients with interstitial lung disease.

The diagnosis and classification of most interstitial lung diseases requires histologic evaluation of lung tissue, obtained by an open lung biopsy to confirm the diagnosis. In addition, it is generally accepted that response to therapy in idiopathic pulmonary fibrosis (IPF) is related to the relative degree of cellularity and fibrosis present. Because only a qualitative assessment of the relative extent and severity of these changes is generally provided, correlation with clinical and physiologic alterations is difficult. This report describes results of a semiquantitative assessment by four pathologists of inflammatory/exudative changes, fibrotic/reparative changes, and airway alterations, in addition to an overall assessment of cellularity and fibrosis in 50 patients with IPF. In 10 randomly selected biopsies examined twice in a blinded fashion, absolute agreement between assessments for a given pathologist varied between 54 and 64% (mean = 57.5%) and in the majority of instances the agreement was greater than would have occurred by chance. There was good agreement for most variables across the four raters on the 101 samples. The mean score for some of the parameters reported by a given rater deviated occasionally from those of the other raters, but no single rater was consistently different from the other raters. A principal component factor analysis revealed that the pathologic features fell into four general groupings: alveolar wall metaplasia, fibrosis, honeycombing, smooth muscle, and vascular changes fell into one group; severity and extent of cellularity in the alveolar wall into a second group; severity and extent of cellularity in the alveolar space into a third group; and interstitial young connective tissue along with granulation tissue in the airways formed the fourth group.(ABSTRACT TRUNCATED AT 250 WORDS)

Previous studies have demonstrated that bradykinin (BK) produces a sympathetically dependent plasma extravasation into the rat knee joint which is, in part, dependent upon the production of a prostaglandin. In the present study, co-administration of the specific prostaglandin, PGE2, markedly enhanced the BK-induced plasma extravasation. In this study we also report that after chemically induced sympathectomy, by chronic pretreatment with 6-hydroxydopamine (6-OHDA), both the plasma extravasation produced by BK and the enhancing effect of PGE2 are markedly attenuated. Plasma extravasation induced by PGE2 alone was small and was not significantly attenuated by sympathectomy. We conclude that BK-induced extravasation involves production of at least two sympathetic postganglionic neuron (SPGN) terminal-dependent factors, one of which is a cyclo-oxygenase product of arachidonic acid metabolism, probably PGE2, (Coderre et al., J. Neurophysiol., 62 (1989) 45-58) and another that is unidentified.

It is not yet known what properties distinguish macrophages which can kill facultative intracellular bacteria, such as Listeria monocytogenes, from those which cannot. Listeria is an organism which requires iron for growth, yet macrophage listericidal mechanisms are also likely to be iron dependent. We show here that resident peritoneal macrophages and thioglycollate-elicited macrophages cannot kill listeria, but proteose peptone-elicited and FCS-elicited macrophages can. All these cell populations phagocytose listeria. Transferrin receptor expression is low on resident cells, intermediate on peptone- and FCS-elicited cells, and high on thioglycollate-elicited cells. Transferrin transports iron into cells via the transferrin receptor: thus, iron content of resident cells is low, of peptone- and FCS-elicited cells is intermediate, and of thioglycollate-elicited cells is high. Moreover, antibody to transferrin, which prevents it binding its receptor, inhibits listericidal macrophages from killing this bacterium. Finally, nonlistericidal cells with high transferrin receptor expression and high intracellular iron become listericidal if they are incubated with apotransferrin, an iron-free ligand which prevents iron uptake by cells. These data suggest that macrophages must have enough available intracellular iron to support listericidal mechanisms, but too much iron favors growth of the bacterium, which no longer can be killed by the macrophage.

Idiopathic pulmonary fibrosis (IPF) is a progressive disease of the lung characterized by an inflammatory infiltrate, alveolar type II cell hypertrophy and hyperplasia, and ultimate parenchymal scarring. The phospholipid composition of the surface-active material recovered by bronchoalveolar lavage (BAL) is abnormal in this disease. In the present study we have extended the analysis of surfactant components in IPF to include the major surfactant-associated protein, surfactant protein A (SP-A). SP-A has been reported to be essential for the formation of tubular myelin, to facilitate the adsorption of phospholipid to the air/liquid interface, and to stimulate uptake and inhibit secretion of surfactant in vitro. The BAL of 25 normal volunteers and 42 patients with interstitial lung disease (ILD) was analyzed for surfactant protein A content by ELISA and for phospholipids. The changes in BAL components were correlated to histopathologic markers at open-lung biopsy, clinical status, and survival. The total phospholipid (PL) recovered at lavage was reduced in patients with IPF relative to normal volunteers (p less than 0.0005). In addition, the percentage of phosphatidyl-glycerol (% PG) was decreased in patients with IPF (p less than 0.0001), whereas the percentage of phosphatidylcholine that was saturated was not altered. The content of surfactant protein A in lavage was reduced, even when normalized for the total amount of surface-active material recovered (SP-A/PL) (p less than 0.007). The reduction in SP-A was not specific to IPF but also occurred in other interstitial lung diseases.(ABSTRACT TRUNCATED AT 250 WORDS)