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PubMed2004

Localization of endothelin receptors in bleomycin-induced pulmonary fibrosis in the rat.

Pulmonary fibrosis is characterized by excessive extracellular matrix deposition with concomitant loss of gas exchange units, and endothelin-1 (ET-1) has been implicated in its pathogenesis. Increased levels of ET-1 from tissues and bronchoalveolar lavage have been reported in patients with pulmonary fibrosis and in animal models after intratracheal bleomycin. We characterized the cellular distribution of alveolar ET receptors by immunohistochemistry in bleomycin-induced pulmonary fibrosis in the rat and determined the regulation by bleomycin of ET receptor mRNA expression in isolated alveolar macrophages and rat lung fibroblasts. We found significant increases in the numbers of fibroblasts and macrophages at day 7 compared to day 28 and control animals. ET(B) receptor immunoreactivity was observed on fibroblasts and invading monocytes. Isolated fibroblasts expressed both ET(A) and ET(B) receptor mRNA, and ET(A) receptor mRNA was upregulated by bleomycin. Isolated resident alveolar macrophages expressed neither ET(A) nor ET(B) receptor mRNA which were also not induced by bleomycin. We conclude that, while ET(B) receptor stimulation of fibroblasts and monocytes recruited during bleomycin-induced lung injury exerts antagonistic effects on fibroblast collagen synthesis, the observed increase in the number of fibroblasts in vivo and upregulation of fibroblast ET(A) receptor mRNA by bleomycin in vitro point to a predominance of the profibrotic effects of ET receptor engagement.

Animals↗

PubMed1992

[The role of oxygen radicals in bleomycin-induced pulmonary fibrosis].

A model of pulmonary fibrosis in rat has been developed using intratracheal administration of bleomycin (BLM) A5 (5mg/kg). Histopathologic features and total lung collagen were studied. We found that type I pneumocytes detached, basement membrane denuded and endothelia edema were the earliest changes in BLM induced pulmonary fibrosis. Serum MDA (an index of lipid peroxidation) level in rats receiving intratracheal bleomycin were increased at earlier time after bleomycin administration. Meanwhile, MDA level in the lung homogenate was elevated too. Our results indicated that the injured type I pneumocytes and endothelia caused by oxygen radicles are the fundamental damages in bleomycin-induced pulmonary fibrosis.

Animals↗

PubMed2001

Pulmonary fibrosis with intractable pneumothorax: new pulmonary manifestation of relapsing polychondritis.

Relapsing Polychondritis is a rare disease which causes the repetitive inflammation of cartilage and connective tissues. Although the large airway is sometimes involved and the stenosis of them often influences the prognosis of the patients, there have been few reports concerning the manifestation of the peripheral lung. A 60-year-old man with pulmonary fibrosis was admitted to a regional hospital due to sudden deafness, and then he suffered from relapsing polychondritis. During the steroid therapy, he also suffered from bilateral pneumothoraces. His computed tomogram revealed many bilateral bullae, emphysematous changes, and fibrotic changes in bilateral lungs. The mechanism of generating peripheral pulmonary manifestations is also discussed.

Blood Cell Count↗

PubMed2002

Decreased level of vascular endothelial growth factor in bronchoalveolar lavage fluid of normal smokers and patients with pulmonary fibrosis.

Vascular endothelial growth factor (VEGF) plays multifunctional roles in both the development of vasculature and the maintenance of vascular function. A decrease in VEGF reduces angiogenesis and induces apoptosis of vascular endothelial cells. Inhibition of the VEGF receptor causes endothelial cell apoptosis and emphysema. We postulated that VEGF concentrations might be reduced in patients with chronic lung diseases. The level of VEGF was evaluated by enzyme-liked immunosorbent assay in bronchoalveolar lavage fluid (BALF) from normal smokers, nonsmoking volunteers, idiopathic pulmonary fibrosis, pulmonary fibrosis associated with a connective tissue disease, and sarcoidosis. The isoforms of VEGF in BALF were determined by high-performance liquid chromatography. VEGF in nonsmoking volunteers was detectable at a high concentration. In contrast, VEGF in most of the normal smokers was below the detectable limit. The VEGF found in nonsmoking volunteers BALF was VEGF165. VEGF was significantly decreased in idiopathic pulmonary fibrosis, pulmonary fibrosis associated with a connective tissue disease, and sarcoidosis compared with nonsmoking volunteers. The smoking patients showed a further decrease in VEGF. These data suggest that the decrease in VEGF in smokers and patients with chronic lung diseases may reduce angiogenesis and induce apoptosis of vascular endothelial cells.

Adult↗

PubMed2005

The polymorphism C5507G of complement receptor 1 does not explain idiopathic pulmonary fibrosis among the Finns.

Idiopathic pulmonary fibrosis is the most common of the idiopathic interstitial lung diseases referring to the histo-pathological entity of usual interstitial pneumonia. It has been hypothesized that inflammation may trigger the multiformic fibrotic lesions found in the affected lung, and defects in the innate immune defense, including the complement, can predispose to pulmonary fibrosis. The polymorphism C5507G in the Complement Receptor 1 gene has been recently associated with idiopathic pulmonary fibrosis. C5507G causes an amino acid change from proline to arginine, and opens a potential cleavage site for trypsin-like enzymes and, therefore, a potential mechanism for increased shedding of the molecule from the cell surface. We studied the polymorphism in 96 Finnish patients with idiopathic pulmonary fibrosis and 164 population based controls. All the patients and controls were C5507 homozygous suggesting that either the Finns do not carry the G5507 polymorphism or it is extremely rare. We conclude that G5507 is not a susceptibility allele for idiopathic pulmonary fibrosis among Finnish patients.

Adult↗

PubMed1996

Reduction in pulmonary fibrosis in vivo by halofuginone.

Pulmonary fibrosis is a disorder causing a high mortality rate for which therapeutic options are limited. Therefore, the effect of halofuginone, a novel inhibitor of collagen type I synthesis, on bleomycin-induced pulmonary fibrosis was studied in rats. Pulmonary fibrosis was induced by intraperitoneal injections of bleomycin for seven consecutive days, and halofuginone was administered intraperitoneally every second day during the entire experimental period of 42 d. Collagen determination in the lungs and the examination of histologic sections showed that halofuginone significantly reduced fibrosis relative to the untreated control rats. We conclude that halofuginone is a potent in vivo inhibitor of bleomycin-induced pulmonary fibrosis, and that it may potentially be used as a novel therapeutic agent for the treatment of this dysfunction.

Animals↗

PubMedDate not supplied

Pulmonary haemodynamics at rest and on exercise in patients with idiopathic pulmonary fibrosis.

We studied pulmonary haemodynamics in 34 patients with idiopathic pulmonary fibrosis (IPF). The diagnosis was established clinically and confirmed by a lung biopsy in 13 subjects. At rest pulmonary hypertension was found in 21 patients, the mean pulmonary artery pressure (PPA) for the group being 23.8 +/- 7.7 mmHg (means +/- SD). In 19 patients subjected to steady-state physical exercise, PPA rose from 23.1 +/- 7.7 mmHg to 40.3 +/- 16.6 mmHg and arterial oxygen tension (PaO2) fell from 77.7 +/- 10.1 mmHg to 62.5 +/- 14.3 mmHg. There was a significant correlation between the rise in PPA and fall in PaO2 on exercise. We found no correlation between pulmonary artery pressure referred to barometric pressure at rest and lung function data, except for a weak correlation between PPA and PaO2. However, pulmonary artery transmural pressure correlated more strongly with PaO2, and additional correlation with VC, FEV1, and lung compliance were found. Our results suggest that pulmonary intravascular pressure and pulmonary hypertension in patients with IPF are affected not only by anatomical restriction of the pulmonary vasculature and alveolar hypoxia but also by the negative intrathoracic pressure.

Adolescent↗

PubMed2001

Potential pathogenesis and clinical aspects of pulmonary fibrosis associated with rheumatoid arthritis.

Pulmonary fibrosis is an extra-articular disorder that can occur in association with rheumatoid arthritis. The differential diagnosis of this disorder is similar to that of idiopathic pulmonary fibrosis, but specific entities such as atypical pulmonary infections and drug-induced interstitial lung disease must be considered as causes of pulmonary fibrosis in patients with rheumatoid arthritis. Although the cause of lung fibrosis in persons with rheumatoid arthritis is unknown, factors that can potentially contribute to the pathogenesis of this pulmonary disease include genetic susceptibility, development of an altered immunologic response, and/or aberrant host repair processes. The clinical course of patients with pulmonary fibrosis and rheumatoid arthritis is heterogeneous but is generally insidious, chronic, and progressive. These patients respond unpredictably to available empiric therapeutic agents and, overall, their prognosis is poor; limited data suggests that the median survival time can be less than 4 years.

Adrenal Cortex Hormones↗

PubMed1994

Improvement in pulmonary hypertension and hypoxemia during nitric oxide inhalation in a patient with end-stage pulmonary fibrosis.

A patient with severe interstitial pulmonary fibrosis, hypoxemia, pulmonary hypertension, and cor pulmonale was given inhaled nitric oxide (NO) followed by intravenous PGE1 to assess the reversibility of pulmonary hypertension. During NO inhalation, there was marked reduction in pulmonary vascular resistance, increased cardiac output, and dramatic improvement in arterial oxygenation. There was no effect on systemic vascular resistance. In contrast, intravenous PGE1 led to rapid arterial oxygen desaturation and worsened dyspnea. The beneficial responses to inhaled NO in this patient suggest that, even in severe chronic lung disease, reversible pulmonary vasoconstriction is present. Inhaled NO thus has a potential therapeutic role as a selective pulmonary vasodilator in patients with interstitial pulmonary fibrosis and cor pulmonale.

Administration, Inhalation↗

PubMed2005

Effect of preoperative pulmonary artery pressure on early survival after lung transplantation for idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is the second largest indication for lung transplantation worldwide. Average 90-day mortality rates for this procedure are 22%. It is unclear what factors predispose patients with IPF to this increased early posttransplant mortality. Pulmonary hypertension may increase the risk of development of early posttransplant complications through several mechanisms. We examined the effect of secondary pulmonary hypertension on 90-day mortality after lung transplantation for IPF. METHODS: An International Society for Heart and Lung Transplant Registry cohort study of 830 patients with IPF transplanted from January 1995 to June 2002 was undertaken. Risk factors were assessed individually and adjusted for confounding by a multivariable logistic regression model. RESULTS: In the univariate analysis, pulmonary hypertension and bilateral-lung transplantation were significant risk factors for increased 90-day mortality. Multivariate analysis confirmed that mean pulmonary artery pressure and bilateral procedure remain independent risk factors after adjustment for potential confounders. Recipient age, ischemia time, cytomegalovirus status mismatch, and donor age were not independent risk factors for early mortality. CONCLUSIONS: Bilateral-lung transplantation carries a greater risk of early mortality than single-lung transplantation for IPF. Increasing pulmonary artery pressure is a risk factor for death after single-lung transplantation in IPF. Mean pulmonary artery pressure should be included in the overall risk assessment of patients with IPF evaluated for lung transplantation.

Adult↗

PubMed1978

Bleomycin-induced diffuse interstitial pulmonary fibrosis in baboons.

Pulmonary fibrosis was induced in eight baboons with bleomycin; five untreated animals were controls. After 45-65 U/kg of bleomycin, lung volumes and diffusing capacity were reduced, and static lung pressure-volume curves were shifted to the right. Right middle lobes were resected at this time in five bleomycin-treated and two control animals. Compared to controls, right middle lobes from bleomycintreated animals had increased weight and contained increased amounts of total protein, collagen, elastin, and DNA; synthesis of collagen and noncollagen protein were also elevated. Occasional alveolar septae were edematous and infiltrated by mononuclear inflammatory cells; a slight increase in collagen was demonstrable histologically. Four of six treated animals died with extensive diffuse interstitial fibrosis after 95 U/kg of bleomycin. Biochemical analyses revealed significantly elevated lobar contents of dry weight, protein, elastin, and collagen. Two animals survived 95 U/kg of bleomycin and were terminated 6 mo after treatment. In these animals, physiologic studies were indicative of restrictive lung disease, but lung histology was nearly normal. Lung weight, total protein, and DNA had returned to control values, but collagen and elastin were increased in amount and concentration. Bleomycin induces an intense inflammatory response in the lung. During this inflammation, connective tissue proliferation occurs in concert with proliferation of other tissue components. Cessation of bleomycin treatment is followed by resolution of inflammation manifested by decreases in tissue mass, cellular content, and nonconnective tissue protein. Collagen and elastin deposited during inflammation are less successfully removed during resolution, leading to a stage characterized by increased concentrations of these proteins. A similar sequence of tissue alterations may occur in idiopathic diffuse interstitial fibrosis of man in response to various lung injuries.

Animals↗

PubMed1989

[Heart-lung transplantation for idiopathic pulmonary fibrosis].

Diffuse idiopathic pulmonary fibrosis (DIPF) carries a poor prognosis, with an average survival of 4 years. A 37-year-old man had been followed by our department for over 5 years for biopsy-proven DIPF. The disease progressed relentlessly, unresponsive to corticosteroid or colchicine treatment. Marked pulmonary hypertension and right heart failure developed. Arterial pO2 decreased to 30 mmHg and he became bedridden and totally dependent on oxygen inhalation. A heart-lung transplantation was successful in June 1987. The anti-rejection regimen included cyclosporine and azathioprine. Subsequently his functional capacity improved remarkably and pO2 reached 87 mmHg on ambient air. Regular weekly followup visits have included physical examination, chest X-ray, cyclosporine blood levels, blood counts and determination of renal function. During a year of followup there has been no rejection episode nor any other major complication. Although experience with lung transplantation for end-stage DIPF is still limited, it is gradually being accepted as the only successful therapeutic approach. The case presented is the first in Israel of successful heart-lung transplantation for DIPF.

Adult↗

PubMed2006

Macrophage metalloelastase (MMP-12) deficiency does not alter bleomycin-induced pulmonary fibrosis in mice.

BACKGROUND: Pulmonary fibrosis is characterized by excessive deposition of extracellular matrix in the interstitium resulting in respiratory failure. The role of remodeling mediators such as metalloproteinases (MMPs) and their inhibitors (TIMPs) in the fibrogenic process remains misunderstood. In particular, macrophage metalloelastase, also identified as MMP-12, is known to be involved in remodeling processes under pathological conditions. However, MMP-12 involvement in pulmonary fibrosis is unknown. Here we investigated fibrotic response to bleomycin in MMP-12 deficient mice. MATERIALS AND METHODS: C57BL/6 mice, Balb/c mice and MMP-12 -/- mice with a C57BL/6 background received 0.3 mg bleomycin by intranasal administration. 14 days after, mice were anesthetized and underwent either bronchoalveolear lavage (BAL) or lung removal. Collagen deposition in lung tissue was determined by Sircoltrade mark collagen assay, MMP activity in BAL fluid was analyzed by zymography, and other mediators were quantified in BAL fluid by ELISA. Real time PCR was performed to assess gene expression in lung removed one or 14 days after bleomycin administration. Student t test or Mann & Whitney tests were used when appropriate for statistical analysis. RESULTS: The development of pulmonary fibrosis in "fibrosis prone" (C57BL/6) mice was associated with prominent MMP-12 expression in lung, whereas MMP-12 expression was weak in lung tissue of "fibrosis resistant" (Balb/c) mice. MMP-12 mRNA was not detected in MMP-12 -/- mice, in conformity with their genotype. Bleomycin elicited macrophage accumulation in BAL of MMP-12 -/- and wild type (WT) mice, and MMP-12 deficiency had no significant effect on BAL cells composition. Collagen content of lung was increased similarly in MMP-12 -/- and WT mice 14 days after bleomycin administration. Bleomycin elicit a raise of TGF-beta protein, MMP-2 and TIMP-1 protein and mRNA in BAL fluids and lung respectively, and no significant difference was observed between MMP-12 -/- and WT mice considering those parameters. CONCLUSION: The present study shows that MMP-12 deficiency has no significant effect on bleomycin-induced fibrosis.

Journal Article↗

PubMed2001

Regulation of the effects of TGF-beta 1 by activation of latent TGF-beta 1 and differential expression of TGF-beta receptors (T beta R-I and T beta R-II) in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is characterised by subpleural fibrosis that progresses to involve all areas of the lung. The expression of transforming growth factor-beta1 (TGF-beta 1), a potent regulator of connective tissue synthesis, is increased in lung sections of patients with IPF. TGF-beta 1 is generally released in a biologically latent form (L-TGF-beta 1). Before being biologically active, TGF-beta must be converted to its active form and interact with both TGF-beta receptors type I and II (T beta R-I and T beta R-II). TGF-beta latency binding protein 1 (LTBP-1), which facilitates the release and activation of L-TGF-beta 1, is also important in the biology of TGF-beta 1. METHODS: Open lung biopsy samples from patients with IPF and normal controls were examined to localise T beta R-I, T beta R-II, and LTBP-1. Alveolar macrophages (AM) and bronchoalveolar lavage (BAL) fluid were examined using the CCL-64 bioassay to determine if TGF-beta is present in its active form in the lungs of patients with IPF. RESULTS: Immunoreactive L-TGF-beta 1 was present in all lung cells of patients with IPF except for fibroblasts in the subepithelial regions of honeycomb cysts. LTBP-1 was detected primarily in AM and epithelial cells lining honeycomb cysts in areas of advanced IPF. In normal lungs LTBP-1 immunoreactivity was observed in a few AM. AM from the upper and lower lobes of patients with IPF secreted 1.6 (0.6) fmol and 4.1 (1.9) fmol active TGF-beta, respectively, while AM from the lower lobes of control patients secreted no active TGF-beta (p< or =0.01 for TGF-beta in the conditioned media from AM obtained from the lower lobes of IPF patients v normal controls). The difference in percentage active TGF-beta secreted by AM from the lower lobes of patients with IPF and the lower lobes of control patients was significant (p< or =0.01), but the difference between the total TGF-beta secreted from these lobes was not significant. The difference in active TGF-beta in conditioned media of AM from the upper and lower lobes of patients with IPF was also not statistically significant. BAL fluid from the upper and lower lobes of patients with IPF contained 0.7 (0.2) fmol and 2.9 (1.2) fmol active TGF-beta, respectively (p< or =0.03). The percentage of active TGF-beta in the upper and lower lobes was 17.6 (1.0)% and 78.4 (1.6)%, respectively (p< or =0.03). In contrast, BAL fluid from control patients contained small amounts of L-TGF-beta. Using immunostaining, both T beta R-I and T beta R-II were present on all cells of normal lungs but T beta R-I was markedly reduced in most cells in areas of honeycomb cysts except for interstitial myofibroblasts in lungs of patients with IPF. TGF-beta 1 inhibits epithelial cell proliferation and a lack of T beta R-I expression by epithelial cells lining honeycomb cysts would facilitate repair of the alveoli by epithelial cell proliferation. However, the presence of both T beta Rs on fibroblasts is likely to result in a response to TGF-beta 1 for synthesis of connective tissue proteins. Our findings show that biologically active TGF-beta 1 is only present in the lungs of patients with IPF. In addition, the effects of TGF-beta 1 on cells may be further regulated by the expression of T beta Rs. CONCLUSION: Activation of L-TGF-beta 1 and the differential expression of T beta Rs may be important in the pathogenesis of remodelling and fibrosis in IPF.

Bronchoalveolar Lavage Fluid↗

PubMed2006

[Idiopathic pulmonary fibrosis (IPF)].

Idiopathic pulmonary fibrosis (IPF) is a progressive, fatal disease that prognosis (INF) has not improved by available therapy. Recently, much attention has focused on the utility of the T-helper type 1 cytokine interferon (IFN)-gamma as a treatment for IPF. The rationale for its use has been based on observations of its properties as an inhibitor of fibroblast proliferation, collagen synthesis and deposition, and expression of profibrotic cytokines. The clinical trial is advanced aiming at the prognosis improvement of IPF patients. Small-scale controlled clinical study in 1999, IFN-gamma has improved the respiratory functions of IPF, which was resistant to steroid therapy. Be based on these results, phase III large-scale study mainly in North America, the lagged effect of respiratory function aggravation was expected in IPF, in which pulmonary functions are mildly or moderately deteriolated. But in progressive cases, interferon gamma-1b did not affect progression-free survival, pulmonary function, or the quality of life.

Clinical Trials as Topic↗

PubMed2003

Immunomodulatory agents for idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic Pulmonary Fibrosis (IPF) or Usual Interstitial Pneumonia (UIP) is a form of chronic fibrosing interstitial pneumonia of unknown aetiology, with progressively deteriorating respiratory function and ultimately death from respiratory failure. Most treatments are intended to suppress inflammation but none has been proven to alter this process. The most widespread approach uses oral corticosteroids; others use immunosuppressive, immunomodulatory or anti-fibrotic agents, alone or with corticosteroids. A Cochrane review of corticosteroids in IPF has found no evidence that they are of benefit. OBJECTIVES: To determine the effect of non-corticosteroid immunosuppressive, anti-fibrotic and immunomodulatory agents in the treatment of IPF(UIP). SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL - The Cochrane Library, Issue 2 2003), MEDLINE (January 1966 to April 2003), EMBASE (January 1985 to April 2003) and with additional handsearching. SELECTION CRITERIA: RCTs/CCTs utilising non-corticosteroid immunosuppressive, anti-fibrotic or immunomodulatory agents versus either placebo or corticosteroids alone in adult patients with histological evidence of IPF(UIP) or with a diagnosis consistent with published American Thoracic Society guidelines were included. DATA COLLECTION AND ANALYSIS: We retrieved abstracts of identified articles and reviewed those possibly fulfilling inclusion criteria and included or excluded. Two reviewers assessed the studies for inclusion in the review. Where doubt existed a third reviewer re-assessed the article and consensus was obtained. Methodological quality was assessed using the Jadad scale and the Cochrane assessment of allocation of concealment. MAIN RESULTS: 59 studies were identified. Quality was generally poor. Only three RCT/CCTs were suitable for meta-analysis, two lesser quality RCTs were included in discussion only, 52 studies were excluded and two ongoing trials were identified. Each high quality trial used a different agent (azathioprine, colchicine, interferon-gamma 1b) and meaningful comparisons are not possible. Azathioprine and Interferon were studied as additional therapy, whilst colchicine was compared with oral corticosteroids. Only interferon was shown to produce any significant improvement in pulmonary function and arterial oxygenation. There may be a small (but undefined) long term survival advantage for azathioprine. One of the lower quality studies showed a marginal benefit for cyclophosphamide and prednisone over prednisone alone; the other showed no benefit for azathioprine and prednisone over prednisone alone. There are no high quality studies utilising cyclophosphamide. REVIEWER'S CONCLUSIONS: There is little good quality information regarding the efficacy of non-corticosteroid agents in IPF(UIP). The older agents have generally not been well evaluated. A number of new agents require further evaluation. Currently there is little to justify the routine use of any non-corticosteroid agent in the management of IPF(UIP).

Azathioprine↗

PubMedDate not supplied

Natural killer cells in Bal and peripheral blood of patients with idiopathic pulmonary fibrosis (IPF).

Idiopathic Pulmonary Fibrosis/ Usual Interstitial Pneumonia (IPF/UIP) represents the most important interstitial pneumonia. ATh2 cytokine pathway predominance, favoring collagen deposition, associated to a deficit in (IFN- gamma) network, seems to be involved in the pathogenesis of this disease. Nonetheless, few data are available about the potentially involved cells. Natural killer cells (NK), are one of the most important subsets implicated in the IFN-gamma network. The aim of this study was to assess NK cells, both in BAL and peripheral blood of 11 patients suffering from IPF (group A) with respect to 11 patients with other interstitial pneumonia (Group B). Our results did not show any statistically significant difference in NK percentage in BAL between group A and B. On the contrary, patients with IPF showed a higher percentage of NK cells (t = 2.41; p < 0.05) and absolute number of cells (t = 2.32; p < 0.05) in peripheral blood, as well as a strong positive correlation between circulating and BAL NK cells (r = 0.69; p < 0.05). This finding shows, for the first time, a relationship between peripheral and lung resident cell environments in humans suggesting a possible systemic involvement in the natural history of IPF.

Antibodies, Monoclonal↗

PubMed2005

Up-regulation and profibrotic role of osteopontin in human idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal disorder characterized by fibroproliferation and excessive accumulation of extracellular matrix in the lung. METHODS AND FINDINGS: Using oligonucleotide arrays, we identified osteopontin as one of the genes that significantly distinguishes IPF from normal lungs. Osteopontin was localized to alveolar epithelial cells in IPF lungs and was also significantly elevated in bronchoalveolar lavage from IPF patients. To study the fibrosis-relevant effects of osteopontin we stimulated primary human lung fibroblasts and alveolar epithelial cells (A549) with recombinant osteopontin. Osteopontin induced a significant increase of migration and proliferation in both fibroblasts and epithelial cells. Epithelial growth was inhibited by the pentapeptide Gly-Arg-Gly-Asp-Ser (GRGDS) and antibody to CD44, while fibroproliferation was inhibited by GRGDS and antibody to alphavbeta3 integrin. Fibroblast and epithelial cell migration were inhibited by GRGDS, anti-CD44, and anti-alphavbeta3. In fibroblasts, osteopontin up-regulated tissue inhibitor of metalloprotease-1 and type I collagen, and down-regulated matrix metalloprotease-1 (MMP-1) expression, while in A549 cells it caused up-regulation of MMP-7. In human IPF lungs, osteopontin colocalized with MMP-7 in alveolar epithelial cells, and application of weakest link statistical models to microarray data suggested a significant interaction between osteopontin and MMP-7. CONCLUSIONS: Our results provide a potential mechanism by which osteopontin secreted from the alveolar epithelium may exert a profibrotic effect in IPF lungs and highlight osteopontin as a potential target for therapeutic intervention in this incurable disease.

Bronchoalveolar Lavage Fluid↗