Treatment of idiopathic pulmonary fibrosis: Is there anything new?

Neutrophils Modulate Fibrogenesis in Chronic Pulmonary Diseases

Chronic inflammatory pulmonary diseases are characterized by recurrent and persistent inflammation of the airways, commonly associated with poor clinical outcomes. Although their etiologies vary tremendously, airway neutrophilia is a common feature of these diseases. Neutrophils, as vital regulators linking innate and adaptive immune systems, are a double-edged sword in the immune response of the lung involving mechanisms such as phagocytosis, degranulation, neutrophil extracellular trap formation, exosome secretion, release of cytokines and chemokines, and autophagy. Although neutrophils serve as strong defenders against extracellular pathogens, neutrophils and their components can trigger various cascades leading to inflammation and fibrogenesis. Here, we review current studies to elucidate the versatile roles of neutrophils in chronic pulmonary inflammatory diseases and describe the common pathogenesis of these diseases. This may provide new insights into therapeutic strategies for chronic lung diseases.

Endothelium-mediated contributions to fibrosis

Fibrosis, characterized by abnormal and excessive deposition of extracellular matrix, results in compromised tissue and organ structure. This can lead to reduced organ function and eventual failure. Although activated fibroblasts, called myofibroblasts, are considered the central players in fibrosis, the contribution of endothelial cells to the inception and progression of fibrosis has become increasingly recognized. Endothelial cells can contribute to fibrosis by acting as a source of myofibroblasts via endothelial-mesenchymal transition (EndoMT), or by becoming senescent, by secretion of profibrotic mediators and pro-inflammatory cytokines, chemokines and exosomes, promoting the recruitment of immune cells, and by participating in vascular rarefaction and decreased angiogenesis. In this review, we provide an overview of the different aspects of fibrosis in which endothelial cells have been implicated.

Evaluation of the antifibrotic potency by knocking down SPARC, CCR2 and SMAD3

BACKGROUND

The genes of SPARC, CCR2, and SMAD3 are implicated in orchestrating inflammatory response that leads to fibrosis in scleroderma and other fibrotic disorders. The aim of the studies is to evaluate synergistic anti-fibrotic potency of the siRNAs of these genes.

METHODS

The efficacy of the siRNA-combination was evaluated in bleomycin-induced mouse fibrosis. The pathological changes of skin and lungs of the mice were assessed by hematoxylin and eosin and Masson's trichrome stains. The expression of inflammation and fibrosis associated genes and proteins in the tissues were assessed by real-time RT-PCR, RNA sequencing, Western blots and ELISA. Non-crosslinked fibrillar collagen was measured by the Sircol colorimetric assay.

FINDINGS

The applications of the combined siRNAs in bleomycin-induced mice achieved favorable anti-inflammatory and anti-fibrotic effects. Activation of fibroblasts was suppressed in parallel with inhibition of inflammation evidenced by reduced inflammatory cells and proinflammatory cytokines in the BALF and/or the tissues by the treatment. Aberrant expression of the genes normally expressed in fibroblasts, monocytes/ macrophage, endothelial and epithelial cells were significantly restrained after the treatment. In addition, transcriptome profiles indicated that some bleomycin-induced alterations of multiple biological pathways were recovered to varying degrees by the treatment.

INTERPRETATION

The application of the combined siRNAs of SPARC, CCR2, and SMAD3 genes ameliorated inflammation and fibrosis in bleomycin-induced mice. It systemically reinstated multiple biopathways, probably through controlling on different cell types including fibroblasts, monocytes/macrophages, endothelial cells and others. The multi-target-combined therapeutic approach examined herein may represent a novel and effective therapy for fibrosis.

Oncostatin M overexpression induces matrix deposition, STAT3 activation, and SMAD1 Dysregulation in lungs of fibrosis-resistant BALB/c mice

Adverse health outcomes in pulmonary fibrosis are associated with extracellular matrix (ECM) accumulation. Although transforming growth factor-β (TGF-β) has been reported to be an important regulator of fibrosis pathogenesis, TGF-β-independent pathways may also be involved. Here, we investigated responses of putative relatively fibrosis-resistant BALB/c mice to transient pulmonary overexpression of oncostatin M (OSM) using an adenovirus vector encoding OSM (AdOSM) and compared responses with the relatively fibrosis-prone C57Bl/6 strain. Interestingly, BALB/c mice showed similar ECM accumulation and collagen 1A1 and 3A1 mRNA elevation to C57Bl/6 mice 7 days after endotracheal administration of AdOSM. TGF-β1 mRNA levels and pSMAD2 signal were not regulated in either strain in total lung extracts. In contrast to C57Bl/6 mice, BALB/c mice lacked eosinophil, Th2 cytokine, and pro-inflammatory cytokine elevation in the broncholveolar space. OSM overexpression induced STAT3 activation and SMAD1/5/8 signaling suppression in lung from both mice strains, which was associated with a downregulation of BMPR2 and BMP ligands, and increased expression of the BMP antagonist gremlin. Although we also observed STAT3 activation and SMAD1/5/8 signaling suppression in mouse lung fibroblast cultures in vitro upon OSM stimulation, immunohistochemistry analyses indicated that the AdOSM-induced pSMAD1/5/8 signal suppression was primarily localized to the airway epithelium. Other gp130 cytokines including IL-6, LIF, CT-1, but not IL-31, also induced STAT3 activation and SMAD1/5/8 signaling suppression in C10 mouse lung epithelial cells and BEAS 2B bronchial epithelial cells, and we found that pharmacological inhibition of STAT3 activation reversed OSM-induced SMAD1/5/8 signaling suppression in vitro. The results demonstrate that OSM induces ECM accumulation in fibrosis-resistant BALB/c mouse lung in the absence of Th2 inflammation or TGF-β signaling, and highlight a dichotomy of STAT3 activation versus SMAD1 suppression in this process.

Single- and Multiple-Dose Pharmacokinetics of Pirfenidone, an Antifibrotic Agent, in Healthy Chinese Volunteers

A randomized, dose-escalating study evaluated the pharmacokinetics of single and multiple oral doses of pirfenidone, a promising antifibrotic agent, in 48 healthy Chinese volunteers. The effects of sex and food on the pharmacokinetics of pirfenidone were also evaluated. Pharmacokinetics was determined from serial blood samples obtained up to 12 hours after administration of single 200-, 400-, or 600-mg doses of pirfenidone and after multiple doses of 400 mg administrated 3 times daily (tid). Plasma levels of pirfenidone and areas under the curve were found to be proportional to dose. Pirfenidone was rapidly absorbed (t(max) = 0.33-1 hours) and cleared (t((1/2)) = 2-2.5 hours). Pharmacokinetic parameters after multiple doses were similar to those after single doses. Food had a significant effect (P < .01) on the extent of absorption (AUC(0-infinity) = 37.4 +/- 15.4 mg x h/L [fed] vs 46.6 +/- 16.8 mg x h/L [fasted]), rate of absorption was considerably (P < .001) prolonged (t(max) = 1.5 +/- 0.4 hours [fed] vs 0.7 +/- 0.2 hours [fasted]), and peak concentrations were significantly (P < .001) decreased (C(max) = 9.2 +/- 2.9 mg/L [fed] vs 13.0 +/- 1.8 mg/L [fasted]). No significant sex differences were noted for pharmacokinetic variables. Pirfenidone was well tolerated. These results support a tid regimen of pirfenidone for the management of idiopathic pulmonary fibrosis. Concomitant intake of food will reduce the rate and extent (about 20%) of absorption, which is associated with better tolerability of pirfenidone.

An alternative therapy for idiopathic pulmonary fibrosis by doxycycline through matrix metalloproteinase inhibition

BACKGROUND

Idiopatiic pulmonary fibrosis (IPF) is a disease of dysregulated fibrogenesis with abnormal matrix metalloproteinase (MMPs) activity, angiogenesis, and profibrotic milieu wherein MMPs inhibition appears to be target-based therapy. We evaluated the role of doxycycline as a nonspecific inhibitor of MMPs in IPF patients.

MATERIALS AND METHODS

Patients of IPF diagnosed on the basis of ATS-ERS consensus criteria were put on oral doxycycline in an open prospective trial. They were followed up for long term with spirometry, 6 min walk test (6MWT), St. Georges respiratory questionnaire (SGRQ), forced vital capacity (FVC), and repeat bronchoscopy while on doxycycline monotherapy for over 24 weeks. Both the initial and follow-up broncho alveolar lavage fluids (BALF) from IPF patients (n = 6) and control subjects (n = 6) were looked for MMP-9, -3, tissue inhibitor of metalloproteinase (TIMP)-1 and vascular endothelial growth factor (VEGF) expression. Additionally, doxycycline's action on MMP activities in vitro was tested in BALF of IPF patients.

RESULTS

Doxycycline intervention showed significant improvement in IPF patients in terms of change in 6MWT, SGRQ, FVC, and quality of life. The level of MMP-9, -3, TIMP-1 and VEGF in the BALF were found significantly higher in the IPF patients compared to the controls while doxycycline therapy reduced those parameters nearer to control value. Doxycycline also showed a significant dose-dependent reduction in the in vitro MMPs activities in BALF.

CONCLUSION

Doxycycline shows significant prospect in the treatment of IPF through its anti MMPs activities. This is the first report on a case series of long-term doxycycline monotherapy in IPF patients.

Attenuation of fibrosis in vitro and in vivo with SPARC siRNA

Introduction

SPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs.

Methods

In in vitro studies, skin fibroblasts obtained from a Tgfbr1 knock-in mouse (TBR1^CA; Cre-ER) were transfected with SPARC siRNA. Gene and protein expressions of the Col1a2 and the Ctgf were examined by real-time RT-PCR and Western blotting, respectively. In in vivo studies, C57BL/6 mice were induced for skin and lung fibrosis by bleomycin and followed by SPARC siRNA treatment through subcutaneous injection and intratracheal instillation, respectively. The pathological changes of skin and lungs were assessed by hematoxylin and eosin and Masson's trichrome stains. The expression changes of collagen in the tissues were assessed by real-time RT-PCR and non-crosslinked fibrillar collagen content assays.

Results

SPARC siRNA significantly reduced gene and protein expression of collagen type 1 in fibroblasts obtained from the TBR1^CA; Cre-ER mouse that was induced for constitutively active TGF-β receptor I. Skin and lung fibrosis induced by bleomycin was markedly reduced by treatment with SPARC siRNA. The anti-fibrotic effect of SPARC siRNA in vivo was accompanied by an inhibition of Ctgf expression in these same tissues.

Conclusions

Specific inhibition of SPARC effectively reduced fibrotic changes in vitro and in vivo. SPARC inhibition may represent a potential therapeutic approach to fibrotic diseases.

Effects of PPAR gamma ligands on TGF-beta1-induced epithelial-mesenchymal transition in alveolar epithelial cells

Background

Transforming growth factor β1 (TGF-β1)-mediated epithelial mesenchymal transition (EMT) of alveolar epithelial cells (AEC) may contribute to lung fibrosis. Since PPARγ ligands have been shown to inhibit fibroblast activation by TGF-β1, we assessed the ability of the thiazolidinediones rosiglitazone (RGZ) and ciglitazone (CGZ) to regulate TGF-β1-mediated EMT of A549 cells, assessing changes in cell morphology, and expression of cell adhesion molecules E-cadherin (epithelial cell marker) and N-cadherin (mesenchymal cell marker), and collagen 1α1 (COL1A1), CTGF and MMP-2 mRNA.

Methods

Serum-deprived A549 cells (human AEC cell line) were pre-incubated with RGZ and CGZ (1 - 30 μM) in the absence or presence of the PPARγ antagonist GW9662 (10 μM) before TGFβ-1 (0.075-7.5 ng/ml) treatment for up to 72 hrs. Changes in E-cadherin, N-cadherin and phosphorylated Smad2 and Smad3 levels were analysed by Western blot, and changes in mRNA levels including COL1A1 assessed by RT-PCR.

Results

TGFβ-1 (2.5 ng/ml)-induced reductions in E-cadherin expression were associated with a loss of epithelial morphology and cell-cell contact. Concomitant increases in N-cadherin, MMP-2, CTGF and COL1A1 were evident in predominantly elongated fibroblast-like cells. Neither RGZ nor CGZ prevented TGFβ1-induced changes in cell morphology, and PPARγ-dependent inhibitory effects of both ligands on changes in E-cadherin were only evident at submaximal TGF-β1 (0.25 ng/ml). However, both RGZ and CGZ inhibited the marked elevation of N-cadherin and COL1A1 induced by TGF-β1 (2.5 ng/ml), with effects on COL1A1 prevented by GW9662. Phosphorylation of Smad2 and Smad3 by TGF-β1 was not inhibited by RGZ or CGZ.

Conclusions

RGZ and CGZ inhibited profibrotic changes in TGF-β1-stimulated A549 cells independently of inhibition of Smad phosphorylation. Their inhibitory effects on changes in collagen I and E-cadherin, but not N-cadherin or CTGF, appeared to be PPARγ-dependent. Further studies are required to unravel additional mechanisms of inhibition of TGF-β1 signalling by thiazolidinediones and their implications for the contribution of EMT to lung fibrosis.

Chinese medicine formula DSQRL versus glucocorticoids for the treatment of experimental pulmonary fibrosis

Pulmonary fibrosis (PF) is a devastating interstitial lung disease that may develop idiopathically or as a complication of many other diseases. The outcome of the current main treatment by glucocorticoids is by no means satisfactory. This study has tested a new Chinese medicine Decoction for Strengthening Qi and Replenishing Lung (DSQRL) for the treatment of experimental PF in comparison with prednisolone. Eighty-five rats with PF induced by CCl(4) were randomly divided into 4 groups to undertake treatment either by (a) high dose of prednisolone; (b) Chinese medicine formula DSQRL; (c) combined treatment of the above two; or (d) sham feeding of water in equal volume. At the end of 60 days treatment, the DSQRL treatment achieved a significantly better outcome than prednisolone in terms of general behavior, histological examination, hydroxyproline content of the lung and inflammatory cell counts in bronchoalveolar lavage fluid. Thus, the newly proposed Chinese medicinal formula DSQRL appears to be a better and promising option for PF than glucocorticoids for the treatment of PF.

Lung transplantation for idiopathic pulmonary fibrosis

BACKGROUND

Outcomes of lung transplantation for idiopathic pulmonary fibrosis (IPF) are thought to be worse than those for other indications, although the reasons are unknown. In addition, the choice of single versus double lung transplantation is unclear. To guide decision-making, we (1) compared survival of patients receiving transplantation for IPF with survival of patients receiving transplantation for non-IPF diagnoses, (2) identified risk factors for mortality after transplantation for IPF, and (3) ascertained whether double lung transplantation for IPF confers a survival advantage.

METHODS

From February 1990 to November 2005, 469 patients underwent lung transplantation, 82 for IPF. Multiphase hazard modeling was used to identify risk factors, and propensity matching was used to compare survival of IPF and non-IPF patients and to assess the effect of single versus double lung transplantation.

RESULTS

Survival estimates after transplantation for IPF were 95%, 73%, 56%, and 44% at 30 days and 1, 3, and 5 years, somewhat worse than for matched non-IPF patients (p = 0.03). Risk factors for mortality were earlier date of transplantation (p = 0.07), single lung transplantation (p = 0.03), and higher wedge pressure (p = 0.003). Survival for double versus single lung transplantation was 81% versus 67% at 1 year and 55% versus 34% at 5 years; however, among matched non-IPF patients, corresponding survivals were 88% versus 71% at 1 year and 72% versus 48% at 5 years (p = 0.3).

CONCLUSIONS

Survival after lung transplantation for IPF is worse than after other indications for transplantation when multiple clinical variables are accounted for. Survival may be improved by double lung transplant.

An antisense oligonucleotide to HSP47 inhibits paraquat-induced pulmonary fibrosis in rats

The most common cause of death from poisoning by the widely used, but highly toxic herbicide paraquat is respiratory failure from pulmonary fibrosis, which develops through pathological overproduction of extracellular matrix proteins such as the collagens. Heat shock protein (HSP47) is a collagen-specific molecular chaperone that assists in the posttranslational modifications of procollagens during collagen biosynthesis. We investigated whether treatment with an HSP47-antisense oligonucleotide would inhibit paraquat-induced pulmonary fibrosis in Wistar rats. Rats randomized into three groups (control, paraquat, and paraquat+antisense). Paraquat (20 mg/kg/day) (n=16) or a saline control (n=10) was administered to groups of Wistar rats. Intratracheal administration of the antisense oligonucleotide (100 nmol/kg in saline) was performed after the initial paraquat treatment (n=16). Treatment with paraquat alone induced pulmonary fibrosis in the entire group, while treatment with the antisense oligonucleotide alone did not produce any substantial change in lung histology. Administration of antisense oligonucleotides produced a substantial reduction in paraquat-induced pulmonary fibrosis. An immunoblot analysis confirmed that the HSP47-antisense oligonucleotide inhibited HSP47 production. These findings indicate that the HSP47-antisense oligonucleotide inhibited paraquat-induced pulmonary fibrosis and pneumopathy in rats.

Endothelin-1 induces alveolar epithelial-mesenchymal transition through endothelin type A receptor-mediated production of TGF-beta1

Endothelin-1 (ET-1) is implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF), but the cellular mechanisms underlying the role it plays in this disease are not well characterized. Epithelial-mesenchymal transition (EMT), which was recently demonstrated in alveolar epithelial cells (AEC), may play an important role in the pathogenesis of IPF and other forms of pulmonary fibrosis. Whether ET-1 contributes to the induction of EMT in AEC is unknown. The aims of this study were to evaluate AEC production of ET-1 and to determine if ET-1 induces EMT in AEC. We demonstrate that ET-1 is produced at physiologically relevant levels by primary AEC and is secreted preferentially toward the basolateral surface. We also demonstrate that AEC express high levels of endothelin type A receptors (ET-A) and, to a lesser extent, type B receptors (ET-B), suggesting autocrine or paracrine function for alveolar ET-1. In addition, ET-1 induces EMT through ET-A activation. Furthermore, TGF-beta1 synthesis is increased by ET-1, ET-1 induces Smad3 phosphorylation, and ET-1-induced EMT is attenuated by a TGF-beta1-neutralizing antibody. Thus, ET-1 is an important mediator of EMT in AEC, acting through ET-A-mediated TGF-beta1 production. These findings increase our basic understanding of the role of ET-1 in pulmonary fibrosis and suggest potential roles for AEC-derived ET-1 in the pathogenesis of other alveolar epithelial-mediated lung diseases.

Therapeutic effect of Chinese medicine formula DSQRL on experimental pulmonary fibrosis

Pulmonary fibrosis (PF) is a restrictive lung disease that may occur idiopathically or as a complication of many diseases. The outcome of the current treatment by glucocorticoids remains very unsatisfactory. This study has tested a new Chinese medicine formula DSQRL for the treatment of experimental PF in comparison with prednisone. Seventy-two rats with PF induced by CCl(4) were randomly divided into four groups to undertake the treatment of either (a) high dose of prednisone; (b) Chinese medicine formula DSQRL; (c) combined treatment of the above two; or (d) tap water of the same volume. At the end of 30 days treatment, the DSQRL treatment achieved a better outcome (p<0.05) than prednisone in terms of histological examination, bronchoalveolar lavage fluid analysis, hydroxyproline assay and complications. The observations support further investigation and clinical trials of this Chinese medicinal formula for the treatment of PF.

Quality of life and health status in interstitial lung diseases

PURPOSE OF REVIEW

The aim of this review is to provide information on the influence of interstitial lung disease on patients' health status and quality of life, with an emphasis on which aspects might be affected by interstitial lung disease.

RECENT FINDINGS

The quality of life of sarcoidosis patients with current symptoms and patients with idiopathic pulmonary fibrosis is mainly impaired in the domains of physical health and level of independence. Concerning health status, sarcoidosis patients report reduced physical functioning, especially when they have current symptoms. The health status of idiopathic pulmonary fibrosis patients is impaired in almost all aspects. Subjectively assessed dyspnea is related to health status. A relationship between treatment and health status has not been found.

SUMMARY

Results from the existing studies show that both illnesses have a substantial impact on patients' life. Studies aiming at measuring quality of life or health status in other interstitial lung diseases are scarce or nonexistent.