orabase and Pulmonary-Fibrosis

The mechanism of bleomycin (Bleo)-induced pulmonary injury is not fully understood. Elevated levels of lung phospholipase A2 (PLA2) have been previously reported following intratracheal (IT) instillation of Bleo, but the role of this enzyme in the pathogenesis of lung injury is not clear. In this pilot study, we have evaluated the effect of a cell impermeable inhibitor of PLA2 (CME) on Bleo-induced pulmonary inflammation in hamsters. Pulmonary injury was induced by a single IT instillation of Bleo (1 unit/0.5 ml saline). Three groups of male Syrian hamsters were evaluated: 1) BLEO-CME animals received IT Bleo and daily intraperitoneal (IP) injections of CME (1 mumole/kg), starting 1 day before IT instillation; 2) BLEO-SAL animals--received IT Bleo and IP injections of saline and 3) SAL-SAL animals--treated with IT and IP administrations of saline. Animals were sacrificed 14 days after IT treatment and lung injury was evaluated histologically by a semiquantitative morphologic index and by a differential cell count of bronchoalveolar lavage fluid. CME treatment significantly ameliorated Bleo-induced lung injury compared to BLEO-SAL animals (P < 0.05). The percentage of neutrophiles in bronchoalveolar lavage fluid was reduced from 17.7 +/- 3.2% (mean +/- S.E.) in BLEO-SAL group to 7.3 +/- 1.7% in BLEO-CME group (P < 0.05), achieving levels comparable to SAL-SAL control animals. These results suggest that treatment with an extracellular PLA2 inhibitor-CME abates Bleo-induced pulmonary injury. This may indicate an active role of PLA2 in the pathogenesis of interstitial pulmonary fibrosis.

Topics: Animals; Bleomycin; Carboxymethylcellulose Sodium; Cricetinae; Enzyme Inhibitors; Injections, Intraperitoneal; Lung Diseases; Male; Mesocricetus; Phosphatidylethanolamines; Phospholipases A; Phospholipases A2; Pilot Projects; Pulmonary Alveoli; Pulmonary Fibrosis; Sodium Chloride

The antifibrotic effects of an interferon inducer, polyinosinic-polycytidylic acid complexed with poly-L-lysine (poly ICLC), was evaluated in a bleomycin-hamster model of pulmonary fibrosis. Hamsters received three consecutive intratracheal doses of bleomycin (2.5, 2.0, and 1.5 U/kg/5 ml) or saline at weekly intervals. Poly ICLC at three doses (0.5, 1.0, and 1.5 mg/kg body weight) or saline was injected intraperitoneally by daily and semiweekly regimens for four weeks, and animals were sacrificed at five weeks. In both the daily and semiweekly poly ICLC regimens, hamsters receiving bleomycin plus poly ICLC demonstrated increased mortality and decreased weight gain compared to the vehicle and bleomycin control groups. The groups receiving bleomycin plus daily poly ICLC demonstrated poly ICLC-dose related effects for weight changes, lung hydroxyproline and lung prolyl hydroxylase activity. Depending on the poly ICLC dose, bleomycin plus daily poly ICLC produced significantly decreased hydroxyproline or significantly increased hydroxyproline and prolyl hydroxylase activity compared to the bleomycin control group. In contrast, the groups receiving bleomycin plus semiweekly poly ICLC did not demonstrate poly ICLC-dose related effects or significant differences from the bleomycin control group for any of the biochemical assays performed. The results of this study indicate that, depending on dose and regimen, poly ICLC can reduce collagen accumulation or produce a synergistic toxicity when administered with multiple doses of bleomycin. The toxic effects may restrict the therapeutic potential of poly ICLC in combination with bleomycin for anticancer therapy.

Topics: Animals; Bleomycin; Carboxymethylcellulose Sodium; Cricetinae; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Hydroxyproline; Injections, Intraperitoneal; Interferon Inducers; Lipid Peroxidation; Lung; Male; Mesocricetus; Poly I-C; Polylysine; Procollagen-Proline Dioxygenase; Pulmonary Fibrosis; Superoxide Dismutase; Weight Gain

Cultured human lung fibroblasts produced 26 to 68% more type III collagen at confluency than at low cell density. This phenomenon occurred in cell lines from normal embryonic and adult lung tissue as well as in cultures established from fibrotic lung tissue. Modulation of the proportions of individual collagen types may be important in the genesis of pulmonary fibrosis.

Topics: Adult; Carboxymethylcellulose Sodium; Cell Count; Chromatography; Collagen; Fibroblasts; Humans; Lung; Pulmonary Fibrosis

Collagens in normal human lung and in idiopathic chronic fibrosis were investigated in terms of their covalent structure and compared for possible alterations in the diseased state. Collagens were solubilized by limited digestion with pepsin under nondenaturing conditions, and after purification they, were fractionated into types I and III. Carboxymethylcellulose and agarose chromatography of both types I and III collagens, and amino acid and carbohydrate analyses of the resulting alpha-chains indicated that the alpha 1 (I), alpha 2, and alpha 1 (III) chains of normal human lung were identical with the human skin alpha-chains in all respects examined except that the normal lung chains contained higher levels of hydroxylysine. Examination of collagens obtained from the diseased lung revealed that the content of hydroxylysine of the alpha 1 (I) and the alpha 1 (III) chains appeared to be diminished as compared to the normal lung chains. The values, expressed as residues per 1,000 residues, are 7.1 and 8.3 for the alpha 1 (I) and the alpha 1 (III) chains, respectively, as compared to 10.0 and 11.1 for the alpha-chains from the normal tissue. The chromatographic properties and amino acid and carbohydrate composition of the alpha-chains from the diseased tissue were otherwise indistinguishable from those of normal lung. In addition, isolation and characterization of the CNBr peptides of alpha 1 (I), alpha 2 and alpha 1 (III) from the diseased lung revealed no significant differences from the CNBr peptides from other human tissues reported previously. Normal and diseased lungs were also digested with CNBr, and the resultant alpha 1 (I) and alpha 1 (III) peptides were separated chromatographically. The relative quantities of these peptides indicate that type III collagen constitutes 33% of the total collagen in normal human lung, with the remainder being type I, whereas in idiopathic chronic pulmonary fibrosis, the relative content of type III collagen is markedly diminished, ranging from 12 to 24% in different patients. These results indicate that an alteration in tissue collagen polymorphism as well as subtle variations in the collagen structure accompany the fibrotic process in the diseased state, and suggest that these alterations may have possible pathogenetic implications.

Topics: Aged; Amino Acids; Carboxymethylcellulose Sodium; Chromatography, Agarose; Chromatography, Ion Exchange; Chronic Disease; Collagen; Cyanogen Bromide; Humans; Male; Middle Aged; Pepsin A; Polymorphism, Genetic; Pulmonary Fibrosis