Bilirubin ameliorates bleomycin-induced pulmonary fibrosis in rats

Many possible treatments for pulmonary fibrosis have been investigated, but except for some current clinical trials, none have succeeded in clinical trials. On the basis of the antioxidant action of bilirubin (BIL), we examined the effects of hyperbilirubinemia on the development of bleomycin (BLM)-induced pulmonary fibrosis in rats. The animals' plasma BIL level was kept within 3 and 10 mg/dl by repeated intravenous infusion of a high dose of BIL. We studied the inhibitory effects of hyperbilirubinemia on BLM-induced pulmonary fibrosis through histopathologic and biochemical analyses. Mortality of rats with BLM-induced pulmonary fibrosis was significantly lower in the three groups with hyperbilirubinemia. The ameliorating effect of hyperbilirubinemia on pulmonary fibrosis was shown by lung histology, as well as by a decreased lung content of hydroxyproline and reduced bronchoalveolar lavage fluid (BALF) concentration of transforming growth factor (TGF)-beta(1). The number of polymorphonuclear leukocytes and lymphocytes in BALF was also decreased in the groups with hyperbilirubinemia. Furthermore, oxidative metabolites of BIL in urine were present at significantly higher levels in BLM-treated rats with hyperbilirubinemia than in those without hyperbilirubinemia. These data suggest that the antioxidative action of BIL can attenuate BLM-induced pulmonary fibrosis, partly by inhibiting lung inflammation and production of TGF-beta1.     

The effect of cigarette smoke on bleomycin-induced pulmonary fibrosis in hamsters

To investigate the effect of cigarette smoke on the development of bleomycin (BLM)-induced pulmonary fibrosis in hamsters, four experimental groups were studied: a control group (C), a cigarette smoke-inhaled group (T), a BLM-administered group (B), and a cigarette smoke-inhaled plus BLM-administered group (TB). Groups T and TB were exposed to sidestream smoke of cigarettes for 30 min/day, 5 days/wk. Groups B and TB were administered 0.5 mg BLM hydrochloride per 100 g body weight endotracheally once on day 30 (Day 0) after housing start. Quantitative morphometry of the lungs revealed that Group TB showed less lung fibrotic change compared with Group B, but based on qualitative observation, the fibrotic lesions of Group TB were intermingled with slight emphysematous changes. Neutrophils in bronchoalveolar lavage fluid were remarkably increased in both the groups, with a peak on Day 1, but the increase in Group TB lasted longer. Alveolar macrophages were increased in both smoking groups (T and TB) compared to the non-smoking groups (C and B). These results suggest that cigarette smoke reduces BLM-induced lung fibrotic changes; however, it simultaneously causes derangement of alveolar architecture. The persistence of increased neutrophils in the early phase after BLM accompanied by exposure to cigarette smoke may play an important role in the mechanism by which smoke ameliorates the effect of BLM.     

白三烯抑制剂对博莱霉素所致大鼠肺纤维化的干预作用

目的 观察白三烯抑制剂(LT-S)齐留通对博莱霉素(BLM)所致大鼠肺纤维化模型肺纤维化形成过程的影响.方法 54只SD雄性大鼠随机分为正常组(C组)、模型对照组(M组)和LT-S组(S组)3组,每组18只.S组于气管内滴注BLM(5 mg/kg)诱导肺纤维化,于造模当天开始每日给予齐留通100 mg/kg灌胃;M组以生理盐水代替齐留通灌胃;C组均用生理盐水代替BLM和齐留通.各组动物均于制模后的第7天、第14天和第28天分别随机处死6只动物,分取肺组织行病理切片苏木精-伊红染色和Masson染色观察肺泡炎和肺纤维化程度、碱水解法检测肺组织羟脯氨酸(Hyp)浓度、免疫组织化学技术检测肺组织α平滑肌肌动蛋白(α-SMA)和转化生长因子β1(TGF-β1)水平.结果 S组肺泡炎和肺纤维化程度及肺组织Hyp含量均显著低于M组,其TGF-β1和α-SMA在肺组织中的表达水平亦均显著低于M组.结论 LT-S可减轻BLM诱导的大鼠肺纤维化,并可能通过抑制TGF-β1蛋白表达而实现对成纤维原细胞增殖的抑制.     

Pain and cyanosis associated with alpha 1-proteinase inhibitor.

PURPOSE: The purpose of this study was to investigate adverse reaction reports of pain and/or cyanosis attributed to alpha 1-proteinase inhibitor (A1PI), a plasma alpha-globulin protein used to treat A1PI deficiency. PATIENTS AND METHODS: The Food and Drug Administration's (FDA) Spontaneous Reporting System for the collection and analysis of suspected adverse reactions to drugs and biologics was searched for all reports with dates from January 1, 1988, through October 31, 1989, in which A1PI was named as the suspect biologic. A case of pain and/or cyanosis was defined and characteristics of cases were compared with all other reactions. Information about the production of A1PI and results from animal studies conducted by the manufacturer were also gathered. RESULTS: Fourteen cases of acute chest pain, back pain, and/or cyanosis among patients receiving A1PI infusions were reported to the FDA. The clinical aspects of reported cases were consistent with a rapidly acting, nonallergic mechanism and were easily distinguished from other reactions associated with A1PI. The characteristics of reported cases, the epidemic curve, and lot-specific analyses suggested a point source and strongly implicated two A1PI lots. Information about the production of A1PI and results from animal studies further implicated high-molecular-weight polysaccharides associated with sucrose stabilization of the suspect lots. CONCLUSION: These cases resemble adverse reactions attributed to complexes of protamine and heparin (a mucopolysaccharide). Similar vasoactive mechanisms are suggested. Research is needed to further define the pathophysiology associated with polysaccharide moieties.     

Effects of vitamin E deficiency on bleomycin-induced pulmonary fibrosis in hamsters]

We examined the effect of free radicals on lung defense mechanism in bleomycin (BLM)-induced pulmonary fibrosis in hamsters. The concentration of vitamin E (VE) in the lung tissue increased significantly after intratracheal BLM administration. VE deficient hamsters showed increased lipid peroxide values in the lung tissue at a very early stage after BLM treatment. This was followed by decreased superoxide dismutase activities in the lung tissue. The results indicate that; 1) VE appears to be necessary for the prevention of lipid peroxidation in BLM-induced oxidant lung injury, 2) VE deficiency produces a large number of free radicals at the early stage after BLM treatment, and might induce protease-antiprotease imbalance within the lung, which probably causes an emphysematous change in the BLM-treated lung at a late stage after BLM administration.     

Proteolytic inactivation of alpha 1-proteinase inhibitor in infected bronchial secretions from patients with cystic fibrosis

The chronic, progressively destructive bronchitis of patients with cystic fibrosis (CF) is characterized by an important imbalance between tissue destroying granulocyte proteases such as granulocyte elastase (GE) and its physiological inhibitors in bronchial secretions. Recent in vitro studies suggest, that proteases derived from bacteria or endogenous proteases may contribute to inactivation of physiological inhibitors of GE. Since only trypsin-unreactive alpha 1-proteinase inhibitor (alpha 1-PI) was detected in CF bronchial secretions, we attempted to identify the mechanism of inactivation of alpha 1-PI. We found a heat stable, serine protease-like enzymatic activity capable of degrading 125I-labelled alpha 1-PI extensively in 22 infected but not in one non-infected CF bronchial secretion. In infected secretions, only degraded alpha 1-PI, which did not migrate like oxidized alpha 1-PI in tandem-crossed immunoelectrophoresis, was detectable. We conclude, that free GE in excess as well as GE bound to bronchial mucosal inhibitor may partly account for the alpha 1-PI-cleaving activity, but that other yet unknown bacterial or host serine proteases also contribute to alpha 1-PI inactivation.     

Lung cytokine production in bleomycin-induced pulmonary fibrosis.

In bleomycin-induced pulmonary fibrosis, lung injury is accompanied with inflammation and subsequent fibrosis. In this study, lung mRNA for several cytokines was measured in bleomycin-treated mice to evaluate their roles in lung fibrosis. Significant increases in tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta) mRNA were found in lungs of bleomycin-treated responder CBA mice but not in nonresponder BALB/c mice. Increases in responder animals peaked on day 7 after bleomycin administration, and subsequently returned toward control levels. This time course paralleled that for the increase in beta-actin mRNA, but preceded the peak increase in mRNA for collagens I and III. When lung macrophages were analyzed for cytokine secretion, differences were observed between alveolar macrophages and interstitial cells, and between cells from bleomycin-responsive CBA and nonresponsive BALB/c mice. Only alveolar macrophages from CBA mice secreted increased amounts of IL-1. TNF-alpha activity was increased in conditioned media of alveolar and interstitial cells of CBA mice, while only alveolar macrophages of nonresponder BALB/c mice secreted any activity. The kinetics of the increased secretion of TNF-alpha was dissimilar for these different cells. These results are consistent with the conclusion that increased production of TNF-alpha and TGF-beta is an important component of the fibrotic process.     

Expression of the alpha 1-proteinase inhibitor gene in human monocytes and macrophages.

Expression of the alpha 1-proteinase inhibitor (alpha 1PI) gene was studied in human mononuclear cells. Using RNA blot and dot hybridization, alpha 1PI mRNA was detected in human peripheral blood monocytes, bronchoalveolar and breast milk macrophages, but not in B or T lymphocytes. Using incorporation of a radiolabeled amino acid precursor, synthesis and secretion of alpha 1PI were demonstrated in human monocytes and macrophages, but not in lymphocytes. In addition, alpha 1PI was secreted in functionally active form as shown by complexing with serine proteases. Biosynthesis of alpha 1PI by mononuclear phagocytes was greatest during the first 24 hr in culture and progressively decreased over the next 10 days. The reduction in alpha 1PI biosynthesis in vitro involved a mechanism acting at the pretranslational level as alpha 1PI mRNA content also progressively declined over 10 days in culture. The ease of sampling human monocytes and macrophages now permits examination of the biochemical defect in homozygous PiZ and PiS alpha 1PI deficiencies and study of the functional significance of locally produced alpha 1PI in normal tissues and sites of injury or inflammation.     

Pulmonary penetration of alpha 1-proteinase inhibitor administered parenterally to dogs

To study the penetration of alpha 1-proteinase inhibitor (A1Pl) into the lungs of healthy dogs, 83 mg/kg of active A1Pl was administered intravenously over 30 min followed by a bolus of 131I-A1Pl. Animals were lavaged 2 to 72 h after infusion, sequential gamma camera scans were acquired, and urine was analyzed for the excretion of desmosine. After a distribution phase, infused A1Pl left the bloodstream with a half-life of 103 +/- 24 h. Analysis of plasma antiprotease activity demonstrated preservation of function of the infused A1Pl. Lavage fluid A1Pl concentration and activity were significantly increased 24 h after infusion. Gamma camera scans demonstrated that lung, liver, and spleen acquired 131I-A1Pl similarly; radioactivities per gram of tissue of these organs were similar at autopsy. Excretion of desmosine did not decrease from a baseline of 157 +/- 59 nmol/24 h after A1Pl infusion, indicating no effect of A1Pl infusion on background elastolysis. These data suggest that intravenous administration of A1Pl can raise lung antiproteinase levels within 24 h despite the absence of preferential uptake by the lung of the infused protein.     

Progressive pulmonary fibrosis in hamsters

The concomitant treatment of hamsters with bleomycin and hyperoxia results in a synergistic development of pulmonary injury. We exposed hamsters for 72 hr to 70% oxygen following a single intratracheal instillation of bleomycin (0.16 U/100 g body weight). Groups of 10 animals were killed at 3, 6, 10, 30, 60, 90, and 120 days after instillation for histopathologic and morphometric assessment. Diffuse alveolar damage developed acutely. At 30 days, the intense acute cellular infiltrate had subsided, leaving a focal interstitial pneumonitis. Morphometric quantitation at 10 days revealed that 33.5 +/- 5.3% (x +/- SE) of the lung was diseased; there was apparent healing by 30 days, when 10.5 +/- 2.0% of the lung was diseased. However, progression to diffuse pneumonitis with fibrosis was seen at 60, 90, and 120 days, when 30.2 +/- 4.9%, 38.5 +/- 5.8%, and 38.8 +/- 4.5% of the lung was diseased, respectively. In vivo pulmonary function studies on treated animals at 25 and 55 days showed decreasing dynamic compliance and increased minute ventilation, which corroborates the presence of interstitial fibrosis. We conclude that simultaneous treatment of hamsters with bleomycin and hyperoxia results in interstitial fibrosis with a distribution and progression that mimics human pulmonary fibrosis. This model appears ideally suited for the study of progressive fibrosis and will be useful when development of a widely distributed lesion is crucial.     

Losartan attenuates bleomycin-induced pulmonary fibrosis in rats

BACKGROUND: In addition to regulating blood pressure and body fluid homeostasis, the renin-angiotensin system is also involved in lung fibrogenesis. OBJECTIVE: To study the effect of losartan, an angiotensin II antagonist, on bleomycin-induced pulmonary fibrosis in rats and its possible mechanism. METHODS: Pulmonary fibrosis was induced in SD rats by intratracheal instillation of bleomycin (5 mg x kg(-1)). Subsequently, the rats received daily losartan (3, 9 and 27 mg x kg(-1)) or prednisone (20 mg x kg(-1)) orally. Six rats in each group were sacrificed 14 and 21 days after intratracheal instillation. Hydroxyproline, superoxide dismutase (SOD), and malondialdehyde (MDA) levels in lung tissues were determined by spectroscopy. The levels of TGF-beta1 in serum were measured by ELISA. Histological changes in the lungs were evaluated by hematoxylin-eosin stain, and scored. RESULTS: Rat body weight evidently decreased while the indices of lung and hydroxyproline contents in lung tissue were significantly increased 14 and 21 days after intratracheal bleomycin instillation. Inflammatory cell infiltration and fibrotic scores were more prominent in the model group compared to the sham group. Losartan (3, 9 and 27 mg.kg(-1), i.g.) apparently attenuated the degree of pulmonary fibrosis. Further study showed that losartan significantly increased SOD levels while it decreased MDA contents in lung homogenates. Serum TGF-beta1 levels of pulmonary fibrosis rats were also decreased by losartan. CONCLUSIONS: Losartan had an inhibitory effect on bleomycin-induced pulmonary fibrosis, and its effect may be associated with its anti-free radicals and the reduction in TGF-beta1.     

Amiodarone-induced pulmonary fibrosis in hamsters

Amiodarone, a cardiac antiarrhythmic agent, has been associated with the development of interstitial pulmonary fibrosis in patients receiving prolonged therapy with the drug. To further assess the toxic effects of amiodarone on lung tissue, Syrian hamsters were given a single intratracheal insufflation of the agent and evaluated for histologic evidence of lung injury. Control animals received intratracheal insufflations of the vehicle in which amiodarone was dissolved. After an initial, transient alveolitis in both experimental and control animals, the amiodarone-treated lungs developed increased interstitial thickening due to fibrinous exudates, alveolar epithelial hyperplasia, inflammatory cell infiltrates, and marked deposition of collagen manifested on trichrome staining. Controls, in contrast, showed nearly complete resolution of the initial alveolitis. An unusual feature of the amiodarone-induced lung injury was reemergence of the alveolitis between 5 and 14 days, which included a marked influx of eosinophils into the lung. Although the precise mechanism of the lung injury is not known, the persistence of the acute inflammatory cells as well as the presence of eosinophils suggests a hypersensitivity-type reaction. Furthermore, the progression of lung injury to fibrosis after a single insult with the drug suggests that mere discontinuation of amiodarone therapy in humans may not reverse the disease process, but that corticosteroid therapy may also be required. Amiodarone appears to be a useful agent to induce diffuse fibrotic reactions in the lung that morphologically resemble idiopathic pulmonary fibrosis in humans.     

Polyinosinic-polycytidylic acid, an interferon inducer, ameliorates bleomycin-induced lung fibrosis in mice.

The inhibitory effect of polyinosinic-polycytidylic acid (Poly IC), an inducer of interferons, on bleomycin-induced lung collagen accumulation was investigated in mice. Poly IC (10 mg/kg, intraperitoneally) or saline was given for 2 days and immediately prior to intratracheal instillation of bleomycin (0.125 units/mouse) or an equivalent volume of saline and thereafter daily for 13 days. Lung hydroxyproline levels in saline-saline (control), Poly IC-saline (Poly IC), bleomycin-saline and bleomycin-Poly IC groups averaged 279, 287, 459, and 358 micrograms/lung, respectively. The bleomycin + Poly IC mice had significantly less lung hydroxyproline than bleomycin mice, but significantly more hydroxyproline than control or Poly IC mice. Similarly, bleomycin + Poly IC mice had significantly less protein in bronchoalveolar lavage fluid (BALF) supernatant than bleomycin mice, but significantly more protein than control or Poly IC mice. Total cell counts for cells recovered from BALF showed significant increases of 174 and 167% in bleomycin and bleomycin + Poly IC as compared to controls, while the Poly IC group showed a significant decrease of 47% which was primarily due to a decrease in alveolar macrophages. The bleomycin group had significantly more neutrophils, monocytes, macrophages, and lymphocytes than control mice, while bleomycin + Poly IC mice lacked the significant increase in lymphocytes. Bleomycin + Poly IC mice had significantly more monocytes than the bleomycin group. All bleomycin-treated mice had lung lesions, but no lesions were observed in control or Poly IC mice. Bleomycin + Poly IC mice had significantly more (58%) lesions than bleomycin. In contrast, the volume of interstitial lesion in bleomycin + Poly IC mice showed significantly less extracellular fibers (decreased by 62%) and no difference in fibroblasts as compared to bleomycin mice. Fibrotic lesions in bleomycin mice were multifocal and varied from large areas of organized connective tissue to thickened septa lined by cuboidal epithelial cells. Interstitial lesions in bleomycin + Poly IC had a significantly greater volume of mononuclear phagocytes and lymphocytes, but less organized connective tissue than the bleomycin group. Poly IC treatment ameliorated bleomycin-induced lung collagen accumulation.     

Leukocyte elastase alpha 1-proteinase inhibitor complexes may diagnose pancreatic abscesses early

Complexes of alpha 1-proteinase inhibitor and leukocyte elastase could be demonstrated by crossed immunoelectrophoresis of the peritoneal fluid from four patients who developed a pancreatic abscess during an attack of pancreatitis. No such complexes were seen in 69 patients with acute pancreatitis without an abscess. The complexes were demonstrable 2-3 days before the abscess was clinically evident. They may thus be diagnostically and therapeutically important. The appearance of these complexes denotes the liberation of large amounts of leukocyte elastase. This may help explain the pathophysiology and high mortality of the pancreatic abscess, since leukocyte elastase is known to cause degradation of all components of connective tissue and also degradation and activation of many components within the different cascade systems.     

Attenuation of bleomycin-induced pulmonary fibrosis by follistatin

RATIONALE: Activins are members of the transforming growth factor-beta superfamily thought to be involved in repair processes after tissue injury. OBJECTIVES: The aim of this study was to clarify whether activin and its antagonist, follistatin, played a significant role in lung injury and fibrosis. METHODS AND RESULTS: In bleomycin (BLM)-treated rat lung, mRNA for the beta(A) subunit of activin was upregulated on Days 3 and 7 and decreased gradually thereafter. Immunoreactive activin A was abundantly expressed in macrophages infiltrated in the lung, and was detected in fibroblasts accumulated in the fibrotic area on Day 28. We then administered follistatin, an activin antagonist, to BLM-treated rats. Follistatin significantly reduced the number of macrophages and neutrophils in bronchoalveolar lavage and reduced the protein content. Histologically, follistatin markedly reduced the number of infiltrating cells, ameliorated the destruction of lung architecture on Day 7, and attenuated lung fibrosis on Day 28. The hydroxyproline content was significantly lower in follistatin-treated rats. In cultured lung fibroblasts, production of activin A was augmented by transforming growth factor-beta, and activin antagonist follistatin significantly inhibited transforming growth factor-beta-induced fibroblast activation. These results suggest that activin A was produced in the lung after BLM treatment and promoted acute inflammation and subsequent fibrosis. CONCLUSIONS: Follistatin is effective in treating acute lung injury and BLM-induced fibrosis by blocking the actions of activin and transforming growth factor-beta.     

Alveolar wall basement membranes in bleomycin-induced pulmonary fibrosis

The ultrastructural characteristics of alveolar wall basement membranes (BM) were defined in an experimental model of pulmonary fibrosis. Lungs of adult hamsters were examined 2 to 60 days after a single intratracheal instillation of 0.5 units of bleomycin sulfate. Sections of lung fixed with tannic acid and glutaraldehyde were analyzed for epithelial basement membrane (EPI-BM) thickness and duplication, and tissue incubated in ruthenium red prior to fixation was evaluated for distribution of EPI-BM anionic sites. There were no major alterations in capillary EPI-BM. Six days after bleomycin, during acute inflammation, there was focal injury to alveolar epithelial cells and resultant denudation of EPI-BM. Denuded EPI-BM was folded with the lamina densa 60% thicker than in control animals, suggesting its active or passive retraction. Despite type 2 cell hyperplasia and repopulation of the epithelium, there was no duplication of EPI-BM. Thirty and 60 days after bleomycin, the epithelium was intact, inflammation had subsided, and widespread but focal fibrosis was present. This stage was characterized by thickening and duplication of the EPI-BM; 10% of EPI-BM on the thin side of the alveolar wall were duplicated at 30 days and 30% at 60 days. Duplication and thickening, although worse in fibrotic areas, also occurred in normal-appearing areas of lung, showing that EPI-BM changes may be the only residuum of previous damage. Duplication of EPI-BM in this model of pulmonary fibrosis is a late rather than an early feature of disease.(ABSTRACT TRUNCATED AT 250 WORDS)