The anti-fibrotic effect of pirfenidone in rat liver fibrosis is mediated by downregulation of procollagen alpha1(I), TIMP-1 and MMP-2

Add-on therapy for pulmonary fibrosis, a forthcoming era with implications for practice: the BI 101550 and RELIEF trials

The therapeutic landscape for idiopathic pulmonary fibrosis (IPF) and progressive fibrosing interstitial lung disease (PFILD) is increasingly complex, with add-on antifibrotic options now in clinical trials, or available for patients progressing on first-line therapy in both conditions. Here, we review two recent trials of potential add-on therapeutic options, the BI 101550 and RELIEF trials. BI 101550 was a phase 2 randomised control trial (RCT) of a novel phosphodiesterase-4 inhibitor in patients with IPF, with a primary end-point of change in forced vital capacity (ΔFVC) (in mL) at 12 weeks. The RELIEF trial was a phase 2 RCT in patients with PFILD, with a primary end-point of ΔFVC (absolute % predicted) over 48 weeks. Whilst the BI 101550 and RELIEF trials showed positive results in their primary end-points, the strengths and weaknesses of both trials are discussed with importance for their interpretation and clinical impact. We review current clinical practice in IPF and PFILD and place the BI101550 and RELIEF trial results in context, highlighting advances and problems with antifibrotic therapies.

Commentary on

Richeldi L, et al. Trial of a preferential phosphodiesterase 4B inhibitor for idiopathic pulmonary fibrosis. N Engl J Med 2022; 386: 2178-2187.Behr J, et al. Pirfenidone in patients with progressive fibrotic interstitial lung diseases other than idiopathic pulmonary fibrosis (RELIEF): a double-blind, randomised, placebo-controlled, phase 2b trial. Lancet Respir Med 2021; 9: 476-486.

Innovated pirfenidone loaded lecithin nanocapsules for targeting liver fibrosis: Formulation, characterization and in vivo study

Increasing interest in developing antifibrotic therapies became a paramount priority due to the globally raised incidence of deaths secondary to hepatic cirrhosis. This work deals with the development of innovative antifibrotic pirfenidone -loaded lecithin core nanocapsules. This with the intention to target the liver and to increase the drug bioavailability, reducing drug liver toxicity, and studying the associated hepatic microenvironment changes. PFD-loaded lecithin nanocapsules (PFD-LENCs) were prepared using the natural lipoid S45 for its dual benefits of being both a lipid and an amphiphilic surfactant. The selected formulation exhibited in vitro sustained drug release up to 24 h compared to free PFD, which is consistent with the studied pharmacokinetic profile. The studied cytotoxicity of PFD as well as PFD-LENCs exhibited negligible cytotoxicity in normal oral epithelial cells. For exploring the capability of the PFD-LENCs in reaching the liver; in vivo tracing using CLSM, in vivo biodistribution to the vital organs were conducted and electron microscopic examination for depicting nanoparticles in liver tissue was performed. Results revealed the capability of the prepared fluorescent LENC2 in reaching the liver, PFD-LENCs detection in the Disse space of the liver and the significant accumulation of PFD-LENCs in liver tissue compared to the other tested organs. The assessment of the necro-inflammatory, antioxidant and the anti-fibrotic effect of PFD-LENCs (50 & 100 mg/kg) exhibited a significant decrease of liver enzymes, TNF-α, TGF-β, Col-1, α-SMA, and TIMP-1, and a significant increase of catalase enzyme and MMP2 compared to free PFD. EM studies, revealed often detection of dendritic cells in PFD-LENCs (100 mg/kg) treated mice and abnormal collagen structure which can represent an adjunct contribution to the antifibrotic mechanism of PFD-LENCs. In conclusion, the development of this innovative PFD loaded lecithin nanocapsules achieved a targeting ability to the liver, controlled drug release, thereby increase the PFD therapeutic value in downregulating hepatic fibrosis in adjunct with the reduction of liver toxicity.

A drug-responsive multicellular human spheroid model to recapitulate drug-induced pulmonary fibrosis

Associated with a high mortality rate, pulmonary fibrosis (PF) is the end stage of several interstitial lung diseases. Although many factors are linked to PF progression, initiation of the fibrotic process remains to be studied. Current research focused on generating new strategies to gain a better understanding of the underlying disease mechanism as the animal models remain insufficient to reflect human physiology. Herein, to account complex cellular interactions within the fibrotic tissue, a multicellular spheroid (MCS) model where human bronchial epithelial cells incorporated with human lung fibroblasts was generated and treated with bleomycin (BLM) to emulate drug-induced PF. Recapitulating the epithelial-interstitial microenvironment, the findings successfully reflected the PF disease, where excessive alpha smooth muscle actin (α-SMA) and collagen type I secretion were noted along with the morphological changes in response to BLM. Moreover, increased levels of fibrotic linked COL13A1, MMP2, WNT3 and decreased expression level of CDH1 provide evidence for the model reliability on fibrosis modelling. Subsequent administration of the FDA approved nintedanib and pirfenidone anti-fibrotic drugs proved the drug-responsiveness of the model.

Pirfenidone is a renal protective drug: Mechanisms, signalling pathways, and preclinical evidence

Renal fibrosis, a characteristic of all chronic kidney diseases, lacks effective therapeutic drugs currently. Pirfenidone (PFD), a small molecule drug with good oral bioavailability, is widely used in idiopathic pulmonary fibrosis and exerts anti-fibrotic, anti-inflammatory, antioxidant, and anti-apoptotic effects. These effects have been attributed to the suppression of cell growth factors (in particular, but not exclusively, transforming growth factor-β) and the epithelial-mesenchymal transition, as well as the possible down-regulation of pro-inflammatory mediators (such as tumour necrosis factor-α), the protection of mitochondrial function, and the regulation of inflammatory cells. Considering the activation of similar anti-fibrotic pathways in lung and kidney disease and the broad activity of PFD, this drug has improved the treatment of the renal fibrotic disease. In this review, we briefly summarize the pharmacokinetics and safety of PFD as well as the mechanisms of PFD focusing on kidney disease. We summarize the effects of PFD on renal function and pathological alterations based on animal experiments, as well as changes in growth factors based on both animal and renal cell experiments. Moreover, given the activation of similar profibrotic pathways in pulmonary diseases and other disorders, we reviewed in-depth the possible signalling pathways targeted by PFD to attenuate renal fibrosis and protect renal function. Finally, we provide an overview of the current clinical trials of PFD for the treatment of renal fibrosis.

Pirfenidone modifies hepatic miRNAs expression in a model of MAFLD/NASH

miRNAs are involved in the development of metabolic associated fatty liver disease (MAFLD) and nonalcoholic steatohepatitis (NASH). We aimed to evaluate modifications by prolonged-release pirfenidone (PR-PFD) on key hepatic miRNAs expression in a MAFLD/NASH model. First, male C57BL/6J mice were randomly assigned into groups and fed with conventional diet (CVD) or high fat and carbohydrate diet (HFD) for 16 weeks. At the end of the eighth week, HFD mice were divided in two and only one half was treated with 300 mg/kg/day of PR-PFD mixed with food. Hepatic expression of miRNAs and target genes that participate in inflammation and lipid metabolism was determined by qRT-PCR and transcriptome by microarrays. Increased hepatic expression of miR-21a-5p, miR-34a-5p, miR-122-5p and miR-103-3p in MAFLD/NASH animals was reduced with PR-PFD. Transcriptome analysis showed that 52 genes involved in lipid and collagen biosynthesis and inflammatory response were downregulated in PR-PFD group. The expression of Il1b, Tnfa, Il6, Tgfb1, Col1a1, and Srebf1 were decreased in PR-PFD treated animals. MAFLD/NASH animals compared to CVD group showed modifications in gene metabolic pathways implicated in lipid metabolic process, inflammatory response and insulin resistance; PR-PFD reversed these modifications.

Artemisinin and artemisinin derivatives as anti-fibrotic therapeutics

Fibrosis is a pathological reparative process that can occur in most organs and is responsible for nearly half of deaths in the developed world. Despite considerable research, few therapies have proven effective and been approved clinically for treatment of fibrosis. Artemisinin compounds are best known as antimalarial therapeutics, but they also demonstrate antiparasitic, antibacterial, anticancer, and anti-fibrotic effects. Here we summarize literature describing anti-fibrotic effects of artemisinin compounds in in vivo and in vitro models of tissue fibrosis, and we describe the likely mechanisms by which artemisinin compounds appear to inhibit cellular and tissue processes that lead to fibrosis. To consider alternative routes of administration of artemisinin for treatment of internal organ fibrosis, we also discuss the potential for more direct oral delivery of Artemisia plant material to enhance bioavailability and efficacy of artemisinin compared to administration of purified artemisinin drugs at comparable doses. It is our hope that greater understanding of the broad anti-fibrotic effects of artemisinin drugs will enable and promote their use as therapeutics for treatment of fibrotic diseases.

Pirfenidone: Molecular Mechanisms and Potential Clinical Applications in Lung Disease

Pirfenidone (PFD) is a pharmacological compound with therapeutic efficacy in idiopathic pulmonary fibrosis. It has been chiefly characterized as an antifibrotic agent, although it was initially developed as an antiinflammatory compound because of its ability to diminish the accumulation of inflammatory cells and cytokines. Despite recent studies that have elucidated key mechanisms, the precise molecular activities of PFD remain incompletely understood. PFD modulates fibrogenic growth factors, thereby attenuating fibroblast proliferation, myofibroblast differentiation, collagen and fibronectin synthesis, and deposition of extracellular matrix. This effect is mediated by suppression of TGF-β1 (transforming growth factor-β1) and other growth factors. Here, we appraise the impact of PFD on TGF-β1 production and its downstream pathways. Accumulating evidence indicates that PFD also downregulates inflammatory pathways and therefore has considerable potential as a viable and innovative antiinflammatory compound. We examine the effects of PFD on inflammatory cells and the production of pro- and antiinflammatory cytokines in the lung. In this context, recent evidence that PFD can target inflammasome pathways and ensuing lung inflammation is highlighted. Finally, the antioxidant properties of PFD, such as its ability to inhibit redox reactions and regulate oxidative stress-related genes and enzymes, are detailed. In summary, this narrative review examines molecular mechanisms underpinning PFD and its recognized benefits in lung fibrosis. We highlight preclinical data that demonstrate the potential of PFD as a nonsteroidal antiinflammatory agent and outline areas for future research.

The in vitro anti-fibrotic effect of Pirfenidone on human pterygium fibroblasts is associated with down-regulation of autocrine TGF-β and MMP-1

We aimed to investigate the in vitro effect of pirfenidone (PFD) on proliferation, migration and collagen contraction of human pterygium fibroblasts (HPFs). HPFs were obtained from tissue explants during pterygium surgery. After treatment with pirfenidone, the HPFs proliferation was measured by MTT, cell cycle progression measured by flow cytometry, cell migration measured by the scratch assay, and cell contractility evaluated in fibroblast-populated collagen gels. The expression of TGF-β1, TGF-β2, MMP-1 and TIMP-1 were also determined with quantitative PCR, western blot and immunofluorescence staining. Results showed pirfenidone markedly inhibited HPFs proliferation with an IC₅₀ of approximately 0.2 mg/ml. After treatment with 0.2 mg/ml pirfenidone for 24 hours, HPFs were at G0/G1 cell cycle arrest, with significantly reduced cell migration capability and collagen contraction, decreased mRNA and protein expressions of TGF-β1, TGF-β2 and MMP-1, and no alterations of TIMP-1 expression. Thus, we have concluded that pirfenidone at 0.2 mg/ml inhibits proliferation, migration, and collagen contraction of HPFs, which is associated with decreased expression of TGF-β and MMP-1, and pirfenidone might represent a potentially therapeutic agent to prevent the recurrence of pterygium after surgery.

Pirfenidone prevents and reverses hepatic insulin resistance and steatohepatitis by polarizing M2 macrophages

Nonalcoholic steatohepatitis (NASH) is associated with lipotoxic liver injury, leading to insulin resistance, inflammation, and fibrosis. Despite its increased global incidence, very few promising treatments for NASH are available. Pirfenidone is an antifibrotic agent used to treat pulmonary fibrosis; it suppresses the pulmonary influx of T cells and macrophages. Here, we investigated the effect of pirfenidone in a mouse model of lipotoxicity-induced NASH via a high-cholesterol and high-fat diet. After 12 weeks of feeding, pirfenidone administration attenuated excessive hepatic lipid accumulation and peroxidation by reducing the expression of genes related to lipogenesis and fatty acid synthesis and enhancing the expression of those related to fatty acid oxidation. Flow cytometry indicated that pirfenidone reduced the number of total hepatic macrophages, particularly CD11c⁺CD206^-(M1)-type macrophages, increased the number of CD11c^-CD206⁺(M2)-type macrophages, and subsequently reduced T-cell numbers, which helped improve insulin resistance and steatohepatitis. Moreover, pirfenidone downregulated the lipopolysaccharide (LPS)-induced mRNA expression of M1 marker genes and upregulated IL-4-induced M2 marker genes in a dose-dependent manner in RAW264.7 macrophages. Importantly, pirfenidone reversed insulin resistance, hepatic inflammation, and fibrosis in mice with pre-existing NASH. These findings suggest that pirfenidone is a potential candidate for the treatment of NASH.

Conditioned Medium from Tonsil-Derived Mesenchymal Stem Cells Relieves CCl4-Induced Liver Fibrosis in Mice

Background

The liver is an organ with remarkable regenerative capacity; however, once chronic fibrosis occurs, liver failure follows, with high mortality and morbidity rates. Continuous exposure to proinflammatory stimuli exaggerates the pathological process of liver failure; therefore, immune modulation is a potential strategy to treat liver fibrosis. Mesenchymal stem cells (MSCs) with tissue regenerative and immunomodulatory potential may support the development of therapeutics for liver fibrosis.

Methods

Here, we induced hepatic injury in mice by injecting carbon tetrachloride (CCl₄) and investigated the therapeutic potential of conditioned medium from tonsil-derived MSCs (T-MSC CM). In parallel, we used recombinant human IL-1Ra, which, as we have previously shown, is secreted exclusively from T-MSCs and resolves the fibrogenic activation of myoblasts. Hepatic inflammation and fibrosis were determined by histological analyses using H&E and Picro-Sirius Red staining.

Results

The results demonstrated that T-MSC CM treatment significantly reduced inflammation as well as fibrosis in the CCl₄-injured mouse liver. IL-1Ra injection showed effects similar to T-MSC CM treatment, suggesting that T-MSC CM may exert anti-inflammatory and anti-fibrotic effects via the endogenous production of IL-1Ra. The expression of genes involved in fibrosis was evaluated, and the results showed significant induction of alpha-1 type I collagen, transforming growth factor beta, and tissue inhibitor of metalloproteases 1 upon CCl₄ injection, whereas treatment with T-MSC CM or IL-1Ra downregulated their expression.

Conclusions

Taken together, these data support the therapeutic potential of T-MSC CM and/or IL-1Ra for the alleviation of liver fibrosis, as well as in treating diseases involving organ fibrosis.

Identification of miRNAs associated with the mechanical response of hepatic stellate cells by miRNA microarray analysis

It has been suggested that hepatic stellate cells (HSCs) could be used in the regulation of liver microcirculation and portal hypertension. The effects of tensile strain on the microRNA (miRNA) profile of HSCs are largely unknown. In this study, we aimed to explore the changes of miRNA expression in tensile strain-treated HSCs. The purity and activation of HSCs were determined by immunofluorescence staining with antibody against desmin and a-SMA, respectively. miRNA profile analysis was performed on HSCs with and without tensile strain treatment (n=3) using microarray analysis. We identified 6 significantly differentially expressed miRNAs (DEMs), including 1 downregulated (rno-miR-125b-2-3p) and 5 upregulated (rno-miR-1224, rho-miR-188-5p, rho-miR-211-3p, rho-miR-3584-5p and rho-miR-466b-5p), which were validated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) experiments. Further analysis of the DEMs revealed that many important biological processes and signal pathways were triggered in tensile strain-treated HSCs. These include the signal transduction mechanisms associated with protein binding, apoptosis, proliferation, and the FoxO and Wnt signaling pathways. In conclusion, this study presents the specific DEMs in tensile strain-treated HSCs. Our study provide novel miRNA-based information that may enhance our understanding of the pathophysiological processes leading to portal hypertension.

Pirfenidone reduces subchondral bone loss and fibrosis after murine knee cartilage injury

Pirfenidone is an anti-inflammatory and anti-fibrotic drug that has shown efficacy in lung and kidney fibrosis. Because inflammation and fibrosis have been linked to the progression of osteoarthritis, we investigated the effects of oral Pirfenidone in a mouse model of cartilage injury, which results in chronic inflammation and joint-wide fibrosis in mice that lack hyaluronan synthase 1 (Has1^-/- ) in comparison to wild-type. Femoral cartilage was surgically injured in wild-type and Has1^-/- mice, and Pirfenidone was administered in food starting after 3 days. At 4 weeks, Pirfenidone reduced the appearance, on micro-computed tomography, of pitting in subchondral bone at, and cortical bone surrounding, the site of cartilage injury. This corresponded with a reduction in fibrotic tissue deposits as observed with gross joint surface photography. Pirfenidone resulted in significant recovery of trabecular bone parameters affected by joint injury in Has1^-/- mice, although the effect in wild-type was less pronounced. Pirfenidone also increased Safranin-O staining of growth plate cartilage after cartilage injury and sham operation in both genotypes. Taken together with the expression of selected extracellular matrix, inflammation, and fibrosis genes, these results indicate that Pirfenidone may confer chondrogenic and bone-protective effects, although the well-known anti-fibrotic effects of Pirfenidone may occur earlier in the wound-healing response than the time point examined in this study. Further investigations to identify the specific cell populations in the joint and signaling pathways that are responsive to Pirfenidone are warranted, as Pirfenidone and other anti-fibrotic drugs may encourage tissue repair and prevent progression of post-traumatic osteoarthritis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:365-376, 2018.

Effects of pirfenidone in acute and sub-chronic liver fibrosis, and an initiation-promotion cancer model in the mouse

Liver fibrosis results from chronic tissue damage and excessive regeneration with accumulation of extracellular matrix proteins; it is a precursor of liver cirrhosis and hepatocellular carcinoma. Liver fibrosis treatments are primarily directed at inflammation, with few options to combat fibrogenesis. Pirfenidone is a drug approved for idiopathic pulmonary fibrosis and this study was focused on anti-fibrotic and anti-cancer potential of pirfenidone in the liver of male B6C3F1/J mice. In a dose-finding study, mice were treated with CCl₄ (0.2ml/kg ip, 2×wk for 4weeks) while on a pirfenidone-containing (0-600mg/kg) diet. Pirfenidone at doses of 300 and 600mg/kg had significant anti-fibrotic (collagen) and anti-inflammatory (serum transaminases and "ballooning" hepatocyte) effects. In a sub-chronic study (14weeks), mice received CCl₄ while on pirfenidone (300mg/kg) diet. Pirfenidone significantly reduced collagen deposition, but had little effect of inflammation and injury. In an initiation-promotion cancer study with N-nitrosodiethylamine and CCl₄, pirfenidone (300mg/kg) did not affect incidence, size, or multiplicity of liver tumors. Overall, we conclude that while pirfenidone exhibits strong anti-fibrotic effects in early stage liver fibrosis, it is less effective in advanced liver fibrosis and was not protective in an initiation-promotion liver cancer.

The stellate cell system (vitamin A-storing cell system)

Past, present, and future research into hepatic stellate cells (HSCs, also called vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells, or Ito cells) are summarized and discussed in this review. Kupffer discovered black-stained cells in the liver using the gold chloride method and named them stellate cells (Sternzellen in German) in 1876. Wake rediscovered the cells in 1971 using the same gold chloride method and various modern histological techniques including electron microscopy. Between their discovery and rediscovery, HSCs disappeared from the research history. Their identification, the establishment of cell isolation and culture methods, and the development of cellular and molecular biological techniques promoted HSC research after their rediscovery. In mammals, HSCs exist in the space between liver parenchymal cells (PCs) or hepatocytes and liver sinusoidal endothelial cells (LSECs) of the hepatic lobule, and store 50-80% of all vitamin A in the body as retinyl ester in lipid droplets in the cytoplasm. SCs also exist in extrahepatic organs such as pancreas, lung, and kidney. Hepatic (HSCs) and extrahepatic stellate cells (EHSCs) form the stellate cell (SC) system or SC family; the main storage site of vitamin A in the body is HSCs in the liver. In pathological conditions such as liver fibrosis, HSCs lose vitamin A, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan, glycosaminoglycan, and adhesive glycoproteins. The morphology of these cells also changes from the star-shaped HSCs to that of fibroblasts or myofibroblasts.

Strategy for treatment of fibrosis in systemic sclerosis: Present and future

Systemic sclerosis (SSc) is a generalized connective tissue disorder characterized by microvascular damage, autoimmunity, and excessive fibrosis of the skin and various internal organs. Regardless of the recent progress in medicine, no radical therapy for SSc has been developed, and the risk of mortality remains high. Therefore, diagnosis in the early disease stage, risk stratification for the development of serious organ involvement and therapeutic intervention with disease-modifying drugs can reduce the maximum degree of fibrosis, leading to improved long-term survival. Recently, new criteria for very early diagnosis of SSc have been proposed, which are expected to be useful for regularly following up patients with very early SSc, regardless of the absence of skin sclerosis, and for detecting the development of internal organ involvement as early as possible. At present, several immunosuppressants, including methotrexate, corticosteroids and cyclophosphamide, are being used for the treatment of fibrosis. Furthermore, mycophenolate mofetil, i.v. immunoglobulins, B-cell depletion, anti-interleukin-6 receptor antibody, autologous hematopoietic stem cell transplantation, rapamycin, pirfenidone and imatinib mesylate are potential candidates for the treatment of SSc, although their efficacy has not been validated. Moreover, targeting transforming growth factor-1 and its signaling pathway or modulating the imbalance between T-helper 1 and 2 immune responses are also attractive therapeutic options. This review describes recent advances in the strategy for treatment of fibrosis in SSc and future perspectives.

Management strategies for liver fibrosis

Liver fibrosis resulting from chronic liver injury are major causes of morbidity and mortality worldwide. Among causes of hepatic fibrosis, viral infection is most common (hepatitis B and C). In addition, obesity rates worldwide have accelerated the risk of liver injury due to nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Also liver fibrosis is associated with the consumption of alcohol, or autoimmune hepatitis and chronic cholangiophaties. The response of hepatocytes to inflammation plays a decisive role in the physiopathology of hepatic fibrosis, which involves the recruitment of both pro- and anti-inflammatory cells such as monocytes and macrophages. As well as the production of other cytokines and chemokines, which increase the stimulus of hepatic stellate cells by activating proinflammatory cells. The aim of this review is to identify the therapeutic options available for the treatment of the liver fibrosis, enabling the prevention of progression when is detected in time.

Anti-fibrotic action of pirfenidone in Dupuytren's disease-derived fibroblasts

BACKGROUND

Dupuytren's disease (DD) is a complex fibro-proliferative disorder of the hand that is often progressive and eventually can cause contractures of the affected fingers. Transforming growth factor beta (TGF-β1) has been implicated as a key stimulator of myofibroblast activity and fascial contraction in DD. Pirfenidone (PFD) is an active small molecule shown to inhibit TGF-β1-mediated action in other fibrotic disorders. This study investigates the efficacy of PFD in vitro in inhibiting TGF-β1-mediated cellular functions leading to Dupuytren's fibrosis.

METHODS

Fibroblasts harvested from (DD) and carpal tunnel (CT)- tissues were treated with or without TGF-β1 and/or PFD and were subjected to cell migration, cell proliferation and cell contraction assays. ELISA; western blots and real time RT-PCR assays were performed to determine the levels of fibronectin; p-Smad2/Smad3; alpha-smooth muscle actin (α-SMA), α2 chain of type I collagen and α1 chain of type III collagen respectively.

RESULTS

Our results show that PFD effectively inhibits TGF-β1-induced cell migration, proliferation and cell contractile properties of both CT- and DD-derived fibroblasts. TGF-β1-induced α-SMA mRNA and protein levels were inhibited at the higher concentration of PFD (800 μg/ml). Interestingly, TGF-β1 induction of type I and type III collagens and fibronectin was inhibited by PFD in both CT- and DD- derived fibroblasts, but the effect was more prominent in DD cells. PFD down-regulated TGF-β1-induced phosphorylation of Smad2/Smad3, a key factor in the TGF-β1 signaling pathway.

CONCLUSION

Taken together these results suggest the PFD can potentially prevent TGF-β1-induced fibroblast to myofibroblast transformation and inhibit ECM production mainly Type I- and Type III- collagen and fibronectin in DD-derived fibroblasts. Further in-vivo studies with PFD may lead to a novel therapeutic application in preventing the progression or recurrence of Dupuytren's disease.

The antifibrotic drug pirfenidone promotes pulmonary cavitation and drug resistance in a mouse model of chronic tuberculosis

Pirfenidone is a recently approved antifibrotic drug for the treatment of idiopathic pulmonary fibrosis (IPF). Because tuberculosis (TB) is characterized by granulomatous inflammation in conjunction with parenchymal destruction and replacement fibrosis, we sought to determine whether the addition of pirfenidone as an adjunctive, host-directed therapy provides a beneficial effect during antimicrobial treatment of TB. We hypothesized that pirfenidone's antiinflammatory and antifibrotic properties would reduce inflammatory lung damage and increase antimicrobial drug penetration in granulomas to accelerate treatment response. The effectiveness of adjunctive pirfenidone during TB drug therapy was evaluated using a murine model of chronic TB. Mice treated with standard therapy 2HRZ/4HR (H, isoniazid; R, rifampin; and Z, pyrazinamide) were compared with 2 alternative regimens containing pirfenidone (Pf) (2HRZPf/4HRPf and 2HRZPf/4HR). Contrary to our hypothesis, adjunctive pirfenidone use leads to reduced bacterial clearance and increased relapse rates. This treatment failure is closely associated with the emergence of isoniazid monoresistant bacilli, increased cavitation, and significant lung pathology. While antifibrotic agents may eventually be used as part of adjunctive host-directed therapy of TB, this study clearly demonstrates that caution must be exercised. Moreover, as pirfenidone becomes more widely used in clinical practice, increased patient monitoring would be required in endemic TB settings.

Effect of Pirfenidone on Vascular Proliferation, Inflammation and Fibrosis in an Abdominal Adhesion Rat Model

AIM

To study the efficacy of pirfenidone for prevention of postoperative adhesion formation in an adhesion rat model.

MATERIALS AND METHODS

Eighteen female Wistar rats were subjected to right-sided parietal peritoneum and right uterine horn adhesion model. Rats were randomized into three groups: group 1 (control) (closure of midline abdominal incision without any agent administration), group 2 (closure of incision after intraperitoneal administration of pirfenidone), and group 3 (closure of incision and only oral administration of pirfenidone for 14 days). Relaparotomy was performed 14 days after the first surgery. Effect of pirfenidone on adhesion formation was assessed on light microscopy by scoring vascular proliferation, inflammation, fibrosis, and collagen formation in the scarred tissue. Effect of pirfenidone on inflammation was assessed by measurement of transforming growth factor-β and interleukin-17 levels in scarred tissue.

RESULTS

The degree of vascular proliferation (1.32 ± 0.39 versus 2.34 ± 0.46, p < 0.001), inflammation (1.60 ± 0.70 versus 2.60 ± 0.52, p < 0.01), and fibrosis (1.50 ± 0.53 versus 2.40 ± 0.52, p < 0.01) were less prominent in group 2 compared to group 1, respectively. Only vascular proliferation was found to be less prominent in group 3 compared to group 1 (1.60 ± 0.42 versus 2.34 ± 0.46, p < 0.01). Intraperitoneal and oral administration of pirfenidone reduced tissue levels of inflammatory markers (TGF-β and IL-17) in parietal and visceral peritoneum compared to control group. Intraperitoneal administration of pirfenidone compared to oral administration was more effective in reducing tissue levels of inflammatory markers.

CONCLUSION

Pirfenidone is an effective agent on the prevention of postoperative vascular proliferation, inflammation and fibrosis in scarred tissue particularly with intraperitoneal administration.

Ethyl Acetate Fraction of Amomum xanthioides Exerts Antihepatofibrotic Actions via the Regulation of Fibrogenic Cytokines in a Dimethylnitrosamine-Induced Rat Model

Amomum xanthioides has been traditionally used to treat diverse digestive system disorders in the Asian countries. We investigated antihepatofibrotic effects of ethyl acetate fraction of Amomum xanthioides (EFAX). Liver fibrosis is induced by dimethylnitrosamine (DMN) injection (intraperitoneally, 10 mg/kg of DMN for 4 weeks to Sprague-Dawley rats). EFAX (25 or 50 mg/kg), silymarin (50 mg/kg), or distilled water was orally administered every day. The DMN injection drastically altered body and organ mass, serum biochemistry, and platelet count, while EFAX treatment significantly attenuated this alteration. Severe liver fibrosis is determined by trichrome staining and measurement of hydroxyproline contents. EFAX treatment significantly attenuated these symptoms as well as the increase in oxidative by-products of lipid and protein metabolism in liver tissues. DMN induced a dramatic activation of hepatic stellate cells and increases in the levels of protein and gene expression of transforming growth factor-beta (TGF-β), platelet derived growth factor-beta (PDGF-β), and connective tissue growth factor (CTGF). Immunohistochemical analyses revealed increases in the levels of protein and gene expression of α-smooth muscle actin. These alterations were significantly normalized by EFAX treatment. Our findings demonstrate the potent antihepatofibrotic properties of EFAX via modulation of fibrogenic cytokines, especially TGF-β in the liver fibrosis rat model.

Decreased Fibrogenesis After Treatment with Pirfenidone in a Newly Developed Mouse Model of Intestinal Fibrosis

BACKGROUND

Fibrosis as a common problem in patients with Crohn's disease is a result of an imbalance toward excessive tissue repair. At present, there is no specific treatment option. Pirfenidone is approved for the treatment of idiopathic pulmonary fibrosis with both antifibrotic and anti-inflammatory effects. We subsequently investigated the impact of pirfenidone treatment on development of fibrosis in a new mouse model of intestinal fibrosis.

METHODS

Small bowel resections from donor mice were transplanted subcutaneously into the neck of recipients. Animals received either pirfenidone (100 mg/kg, three times daily, orally) or vehicle.

RESULTS

After administration of pirfenidone, a significantly decreased collagen layer thickness was revealed as compared to vehicle (9.7 ± 1.0 versus 13.5 ± 1.5 µm, respectively, **P < 0.001). Transforming growth factor-β and matrix metalloproteinase-9 were significantly decreased after treatment with pirfenidone as confirmed by real-time PCR (0.42 ± 0.13 versus 1.00 ± 0.21 and 0.46 ± 0.24 versus 1.00 ± 0.62 mRNA expression level relative to GAPDH, respectively, *P < 0.05). Significantly decreased transforming growth factor-β after administration of pirfenidone was confirmed by Western blotting.

CONCLUSION

In our mouse model, intestinal fibrosis can be reliably induced and is developed within 7 days. Pirfenidone partially prevented the development of fibrosis, making it a potential treatment option against Crohn's disease-associated fibrosis.

Role and New Insights of Pirfenidone in Fibrotic Diseases

Pirfenidone (PFD) is a non-peptide synthetic molecule issued as a broad-spectrum anti-fibrotic drug with the ability to decrease TGF-β1, TNF-α, PDGF and COL1A1 expression, which is highly related to prevent or remove excessive deposition of scar tissue in several organs. Basic and clinical evidence suggests that PFD may safely slow or inhibit the progressive fibrosis swelling after tissue injuries. Furthermore, a number of evidence suggests that this molecule will have positive effects in the treatment of other inflammatory diseases. This review contains current research in which PFD has been used as the treatment of several diseases, and focus mainly in the outcomes related to improve inflammation and fibrogenesis. Therefore, the main goal of this review is to focus on the novel findings of PFD efficacy rather than deepen in the chemical aspects of the molecule.

Antifibrotic therapy in simian immunodeficiency virus infection preserves CD4+ T-cell populations and improves immune reconstitution with antiretroviral therapy

Even with prolonged antiretroviral therapy (ART), many human immunodeficiency virus-infected individuals have <500 CD4(+) T cells/µL, and CD4(+) T cells in lymphoid tissues remain severely depleted, due in part to fibrosis of the paracortical T-cell zone (TZ) that impairs homeostatic mechanisms required for T-cell survival. We therefore used antifibrotic therapy in simian immunodeficiency virus-infected rhesus macaques to determine whether decreased TZ fibrosis would improve reconstitution of peripheral and lymphoid CD4(+) T cells. Treatment with the antifibrotic drug pirfenidone preserved TZ architecture and was associated with significantly larger populations of CD4(+) T cells in peripheral blood and lymphoid tissues. Combining pirfenidone with an ART regimen was associated with greater preservation of CD4(+) T cells than ART alone and was also associated with higher pirfenidone concentrations. These data support a potential role for antifibrotic drug treatment as adjunctive therapy with ART to improve immune reconstitution.

Renoprotective mechanisms of pirfenidone in hypertension-induced renal injury: through anti-fibrotic and anti-oxidative stress pathways

Pirfenidone (PFD) is a novel anti-fibrotic agent that targets TGFβ. However, the mechanisms underlying its renoprotective properties in hypertension-induced renal injury are poorly understood. We investigated the renoprotective properties of PFD and clarified its renoprotective mechanisms in a rat hypertension-induced renal injury model. Dahl salt-sensitive rats were fed a high-salt diet with or without 1% PFD for 6 weeks. During the administration period, we examined the effects of PFD on blood pressure and renal function. After the administration, the protein levels of renal TGFβ, Smad2/3, TNFα, MMP9, TIMP1, and catalase were examined. In addition, total serum antioxidant activity was measured. Compared to untreated rats, PFD treatment significantly attenuated blood pressure and proteinuria. Histological study showed that PFD treatment improved renal fibrosis. PFD may exert its anti-fibrotic effects via the downregulation of TGFβ-Smad2/3 signaling, improvement of MMP9/TIMP1 balance, and suppression of fibroblast proliferation. PFD treatment also increased catalase expression and total serum antioxidant activity. In contrast, PFD treatment did not affect the expression of TNFα protein, macrophage or T-cell infiltration, or plasma interleukin 1β levels. PFD prevents renal injury via its anti-fibrotic and anti-oxidative stress mechanisms. Clarifying the renoprotective mechanisms of PFD will help improve treatment for chronic renal diseases.

Treatment with pirfenidone for two years decreases fibrosis, cytokine levels and enhances CB2 gene expression in patients with chronic hepatitis C

BACKGROUND

The aim of this study was to assess whether two-years treatment with Pirfenidone influences necroinflammation, fibrosis and steatosis, serum levels of TGF-β1, IL-6, TNF-α and CB1 and CB2 gene expression, in patients with chronic hepatitis C (CHC).

METHODS

Twenty-eight patients out of 34 with CHC virus infection were enrolled in the study and received Pirfenidone (1200 mg/day) for 24 months. Six patients dropped out after 12 months of PFD. Liver biopsies and serum samples were obtained at the beginning and end of treatment. Modified HAI was calculated. CB1 and CB2 gene expression was correlated with fibrosis progression alongside with necroinflammation and steatosis. TGF-β1, IL-6, TNF-α and liver transaminases were measured in serum at two-months intervals. HCV genotype and viral load were also assessed. Quality of life was evaluated by SF36 questionnaires and the prognosis of disease was assessed with Child-Pugh score. The Wilcoxon test matched-pair signed ranks were used to analyze the outcomes.

RESULTS

Intention to treat analyses were performed for biochemistry and clinical parameters. At the end of treatment, necroinflammation grading was reduced in an average of 3.2 points in 82% of patients (p < 0.05) and Ishak's fibrosis stage decreased 2-points average in 67% of patients (p < 0.05). Steatosis decreased in 61% of patients. IL-6 and TGF-β1 serum levels decreased significantly in 93% and 67% of patients (p < 0.05), respectively, while TNF-α diminished in 47% of patients. ALT and AST tended to normalize in 81% of patients; CB2 mRNA levels increased in 86% and CB1 expression diminished in 29% of patients. Both, quality of life and Child-Pugh score improvements were reported in all patients.

CONCLUSIONS

Pirfenidone for two years benefits CHC patients and improves inflammation, fibrosis and steatosis in higher number of patients as previously shown for 12-months treatment with PFD. Additionally, PFD improved TGFβ1 and IL-6 levels and diminished liver expression of anti-fibrogenic receptor CB2.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02161952. Protocol Registration Date: 06/11/2014.

Therapeutic potential of Pirfenidone for treating equine corneal scarring

OBJECTIVE

To evaluate the safety and efficacy of Pirfenidone (PFD) in the treatment of equine corneal fibrosis using an in vitro model.

METHODS

Healthy donor equine corneas were collected and used to generate primary equine corneal fibroblasts (ECFs) by growing cultures in minimal essential medium supplemented with 10% fetal bovine serum. Equine corneal myofibroblasts (ECMs), used as a model of equine corneal fibrosis, were produced by growing ECF cultures in serum-free medium containing transforming growth factor β1 (1 ng/mL). Trypan blue viability assays and changes in ECF morphology were utilized to determine the optimal PFD dose for this in vitro model. Trypan blue viability, phase-contrast microscopy, and TUNEL assays were used to evaluate the cytotoxicity of PFD. Scratch and MTT assays were used to evaluate the effect of PFD on cellular migration and proliferation. Real-time PCR, immunoblot analysis, and immunocytochemistry were employed to determine the efficacy of PFD to inhibit ECM formation in vitro.

RESULTS

Topical PFD application at 200 μg/mL successfully decreased αSMA expression when compared to the TGFβ1 only treatment group (P < 0.01). PFD application ≤ 200 μg/mL did not affect ECF phenotype or cellular viability and did not result in significant cytotoxicity.

CONCLUSIONS

Pirfenidone safely and effectively inhibits TGFβ1-induced equine corneal fibrosis in vitro. In vivo studies are warranted.

Management of fibrosis: the mesenchymal stromal cells breakthrough

Fibrosis is the endpoint of many chronic inflammatory diseases and is defined by an abnormal accumulation of extracellular matrix components. Despite its slow progression, it leads to organ malfunction. Fibrosis can affect almost any tissue. Due to its high frequency, in particular in the heart, lungs, liver, and kidneys, many studies have been conducted to find satisfactory treatments. Despite these efforts, current fibrosis management therapies either are insufficiently effective or induce severe adverse effects. In the light of these facts, innovative experimental therapies are being investigated. Among these, cell therapy is regarded as one of the best candidates. In particular, mesenchymal stromal cells (MSCs) have great potential in the treatment of inflammatory diseases. The value of their immunomodulatory effects and their ability to act on profibrotic factors such as oxidative stress, hypoxia, and the transforming growth factor-β1 pathway has already been highlighted in preclinical and clinical studies. Furthermore, their propensity to act depending on the microenvironment surrounding them enhances their curative properties. In this paper, we review a large range of studies addressing the use of MSCs in the treatment of fibrotic diseases. The results reported here suggest that MSCs have antifibrotic potential for several organs.

Fluorofenidone attenuates hepatic fibrosis by suppressing the proliferation and activation of hepatic stellate cells

Fluorofenidone (AKF-PD) is a novel pyridone agent. The purpose of this study is to investigate the inhibitory effects of AKF-PD on liver fibrosis in rats and the involved molecular mechanism related to hepatic stellate cells (HSCs). Rats treated with dimethylnitrosamine or CCl4 were randomly divided into normal, model, AKF-PD treatment, and pirfenidone (PFD) treatment groups. The isolated primary rat HSCs were treated with AKF-PD and PFD respectively. Cell proliferation and cell cycle distribution were analyzed by bromodeoxyuridine and flow cytometry, respectively. The expression of collagen I and α-smooth muscle actin (α-SMA) were determined by Western blot, immunohistochemical staining, and real-time RT-PCR. The expression of cyclin D1, cyclin E, and p27(kip1) and phosphorylation of MEK, ERK, Akt, and 70-kDa ribosomal S6 kinase (p70S6K) were detected by Western blot. AKF-PD significantly inhibited PDGF-BB-induced HSC proliferation and activation by attenuating the expression of collagen I and α-SMA, causing G0/G1 phase cell cycle arrest, reducing expression of cyclin D1 and cyclin E, and promoting expression of p27(kip1). AKF-PD also downregulated PDGF-BB-induced MEK, ERK, Akt, and p70S6K phosphorylation in HSCs. In rat liver fibrosis, AKF-PD alleviated hepatic fibrosis by decreasing necroinflammatory score and semiquantitative score, and reducing expression of collagen I and α-SMA. AKF-PD attenuated the progression of hepatic fibrosis by suppressing HSCs proliferation and activation via the ERK/MAPK and PI3K/Akt signaling pathways. AKF-PD may be used as a potential novel therapeutic agent against liver fibrosis.

Antifibrotic effect of pirfenidone on human pterygium fibroblasts

OBJECTIVE

The effects of pirfenidone were investigated on cultured human pterygium fibroblasts (HPFs).

METHODS

HPFs were obtained from pterygium surgery and subjected to primary culture. After treatment with 0.5, 1.0 or 1.5 mg/mL pirfenidone, MTT and cell migration assays were performed, and procollagen secretion and TGF-β expression were measured by Western blotting and immunofluorescence analysis.

RESULTS

Pirfenidone had a significant inhibitory effect on HPF proliferation, migration and collagen synthesis. There were no differences between the cells treated with 0.5, 1.0 and 1.5 mg/mL pirfenidone and the controls in the MTT assay. After 48 h of treatment with 1.0 or 1.5 mg/mL pirfenidone, TGF-β expression was significantly decreased.

CONCLUSIONS

These findings demonstrate that pirfenidone inhibits the proliferation, migration and procollagen secretion of HPFs at nontoxic concentrations by decreasing TGF-β expression. Thus, pirfenidone may be considered as a safe adjuvant for pterygium surgery to prevent recurrence.

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.

Macrophages and fibrosis: How resident and infiltrating mononuclear phagocytes orchestrate all phases of tissue injury and repair

Certain macrophage phenotypes contribute to tissue fibrosis, but why? Tissues host resident mononuclear phagocytes for their support to maintain homeostasis. Upon injury the changing tissue microenvironment alters their phenotype and primes infiltrating monocytes toward pro-inflammatory macrophages. Several mechanisms contribute to their deactivation and macrophage priming toward anti-inflammatory and pro-regenerative macrophages that produce multiple cytokines that display immunosuppressive as well as pro-regeneratory effects, such as IL-10 and TGF-beta1. Insufficient parenchymal repair creates a tissue microenvironment that becomes dominated by multiple growth factors that promote the pro-fibrotic macrophage phenotype that itself produces large amounts of such growth factors that further support fibrogenesis. However, the contribution of resident mononuclear phagocytes to physiological extracellular matrix turnover implies also their fibrolytic effects in the late stage of tissue scaring. Fibrolytic macrophages break down fibrous tissue, but their phenotypic characteristics remain to be described in more detail. Together, macrophages contribute to tissue fibrosis because the changing tissue environments prime them to assist and orchestrate all phases of tissue injury and repair. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.

Pirfenidone structural isosteres: design, synthesis and spectral study

Series of 5-substituted arylpyridin-2(1H)-ones and arylpyrimidin-4(3H)-ones were designed and synthesized based on pirfenidone, a compound which shows promising therapeutic effects for treatment of fibrosis. The compounds 1a–c, 2a–c and 3a–c were obtained under mild conditions by arylation of the appropriate heterocyclic amines with arylboronic acids under Chan-Lam-Evans conditions. The synthesis of the useful synthon N-(4-methoxyphenyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-(1H)-pyridin-2-one (4) is also reported. All compounds were characterized by spectral and elemental analysis and structural elucidation by 1H and 13C NMR is discussed herein.

Polyprenols from Taxus chinensis var. mairei prevent the development of CCl₄-induced liver fibrosis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

The aim of this study was to investigate the anti-fibrotic effects and the possible underlying mechanisms of taxus polyprenols (TPs) isolated from the needles of Taxus chinensis var. mairei.

MATERIALS AND METHODS

The animals were randomly divided into normal control with vehicles only (olive oil), rat model given CCl₄ only, CCl₄+low TPs (48 mg/kg), CCl₄+medium TPs (120 mg/kg), CCl₄+high TPs (300 mg/kg), and CCl₄+Polyene phosphatidylcholine (PP, 120 mg/kg). The rat model of liver fibrosis was induced by subcutaneous injection of 40% (v/v) of CCl₄ diluted in olive oil (3 mL/kg body weight) twice per week for 8 weeks. Liver histopathological study was performed. Aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and albumin (ALB) of the serum were determined for evaluating the liver function. In order to reveal the possible mechanisms of the anti-fibrotic effects, oxidative stress level, hepatic collagen metabolism, and hepatic stellate cells (HSCs) activation were investigated. Furthermore, the mRNA expression of the fibrotic-related factors was measured by the quantitative real-time RT-PCR.

RESULTS

TPs successfully attenuated liver injury induced by CCl₄ shown by histopathological sections of livers and improved liver function as indicated by decreased ALT, AST and ALP levels and increased ALB levels in serum of the rats. TPs significantly increased the hepatic Cu/Zn SOD and GSH-Px activities along with GSH content while a remarkable decrease in MDA content. Both immunohistochemical staining and mRNA expression levels of α-SMA indicated a profound suppression of HSCs activation. Furthermore, it significantly inhibited the mRNA expression of the pro-fibrotic cytokines Col α1(I), Col α1(Ш), MMP-2, TIMP-1, TIMP-2, PDGF-β, TGF-β1, CTGF and TNF-α and restored the hepatoprotective factor HGF.

CONCLUSION

These results suggest that the protective effects of TPs in chronic CCl₄-induced liver fibrosis might be related with the reduction of oxidative damage, the inhibition of HSCs activation, the down-regulation of pro-fibrogenic stimuli and the protection of hepatocytes.

Pirfenidone inhibits TGF-β1-induced over-expression of collagen type I and heat shock protein 47 in A549 cells

Background

Pirfenidone is a novel anti-fibrotic and anti-inflammatory agent that inhibits the progression of fibrosis in animal models and in patients with idiopathic pulmonary fibrosis (IPF). We previously showed that pirfenidone inhibits the over-expression of collagen type I and of heat shock protein (HSP) 47, a collagen-specific molecular chaperone, in human lung fibroblasts stimulated with transforming growth factor (TGF)-β1 in vitro. The increased numbers of HSP47-positive type II pneumocytes as well as fibroblasts were also diminished by pirfenidone in an animal model of pulmonary fibrosis induced by bleomycin. The present study evaluates the effects of pirfenidone on collagen type I and HSP47 expression in the human alveolar epithelial cell line, A549 cells in vitro.

Methods

The expression of collagen type I, HSP47 and E-cadherin mRNAs in A549 cells stimulated with TGF-β1 was evaluated by Northern blotting or real-time PCR. The expression of collagen type I, HSP47 and fibronectin proteins was assessed by immunocytochemical staining.

Results

TGF-β1 stimulated collagen type I and HSP47 mRNA and protein expression in A549 cells, and pirfenidone significantly inhibited this process. Pirfenidone also inhibited over-expression of the fibroblast phenotypic marker fibronectin in A549 cells induced by TGF-β1.

Conclusion

We concluded that the anti-fibrotic effects of pirfenidone might be mediated not only through the direct inhibition of collagen type I expression but also through the inhibition of HSP47 expression in alveolar epithelial cells, which results in reduced collagen synthesis in lung fibrosis. Furthermore, pirfenidone might partially inhibit the epithelial-mesenchymal transition.

Effects of an anti-transforming growth factor-β agent (pirfenidone) on strabismus surgery in rabbits

PURPOSE

To evaluate the usefulness of an anti-transforming growth factor-β (TGF-β) agent, pirfenidone (PFD) on postoperative inflammation and fibrosis following strabismus surgery in rabbits.

METHODS

Both eyes of 16 New Zealand white rabbits underwent reinsertion of the superior rectus muscle (SRM). After reinsertion of the SRM, PFD-loaded liposomes (0.5 mg/ml) were injected into the right eye (PFD group) and normal saline-loaded liposomes was injected into the left eye (control group), subconjunctivally (0.4 ml). To assess the postoperative inflammatory changes and fibrosis of the SRM, immunofluorescence staining with anti-CD11b antibody was performed at 3 days postoperatively, and Masson's trichrome staining was performed at 4 weeks postoperatively. To evaluate the toxicity of PFD on muscle fibers, the integrity of the muscle fibers was examined by transmission electron microscopy (TEM) at 3 days and 4 weeks postoperatively.

RESULTS

CD11b protein expression was significantly reduced in the PFD group compared with the control group at 3 days postoperatively (p = 0.012). Masson trichrome staining, which stains collagen, was diminished in the PFD group at 4 weeks postoperatively. TEM revealed disorganized muscle fibers and vacuoles in both groups, but this was less prominent in the PFD group.

CONCLUSIONS

Intraoperative injection of PFD may be effective as an adjunctive treatment to decrease inflammation and fibrosis resulting from strabismus surgery.

Fluorofenidone inhibits Ang II-induced apoptosis of renal tubular cells through blockage of the Fas/FasL pathway

OBJECTIVES

The present study was designed to investigate the inhibitory effects of fluorofenidone on Ang II-induced apoptosis in renal tubular cells and the related signaling pathway.

METHODS

Rat proximal tubular epithelial cells (NRK-52E) were used to examine the anti-apoptosis effects of fluorofenidone. Cell proliferation was assessed by methyl thiazolyl tetrazolium assay. Apoptosis was examined by AO/EB staining and TUNEL assay. The expression of Fas/FasL pathway members, including Fas, FasL, Bax, Bcl-2, Caspase-8, and Caspase-3 was detected by real-time RT-PCR and/or Western blot, respectively. The activity of Caspase-8 and Caspase-3 was detected by spectrophotometry.

RESULTS

Fluorofenidone didn't affect the proliferation of NRK-52E cells, but significantly inhibited the apoptosis of NRK-52E cells induced by Ang II. Fluorofenidone significantly reduced Ang II-induced increases in Fas, FasL, Bax, Caspase-8 and Caspase-3 at the mRNA level. Consistent with these observations, fluorofenidone also prevented Ang II-mediated up-regulation of FasL and Bax at the protein level. Additionally, Ang II-induced activation of Caspase-8 and Caspase-3 as well as Ang II-initiated downregulation of Bcl-2 at both mRNA and protein levels was all prevented by fluorofenidone.

CONCLUSIONS

Fluorofenidone can inhibit Ang II-induced apoptosis of renal tubular cells through blockage of the Fas/FasL pathway.

Protective effects of Phyllanthus amarus on fibrotic markers during alcohol and polyunsaturated fatty acid-induced toxicity

Alcoholic liver disease (ALD) remains a major problem, with significant morbidity and mortality worldwide. One of the serious consequences of ALD is hepatic fibrosis. This happens when the matrix synthesis rate exceeds that of matrix degradation. Matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) play a key role in matrix remodeling. Disruption of MMP/TIMP balance can lead to excessive accumulation of extracellular matrix components resulting in severe liver injury. The focus of the present study is to analyze the effect of Phyllanthus amarus on MMP and TIMPs activity in alcohol and thermally oxidized polyunsaturated fatty acid (PUFA)-induced hepatic fibrosis. Male albino Wistar rats were used for the study. The matrix metalloproteinase expression was found to be significantly decreased and the levels of TIMPs and the collagen were significantly increased in alcohol + thermally oxidized PUFA-treated rats. Administration of Phyllanthus amarus extract significantly decreased the levels of collagen and TIMPs; and positively modulated the expression of MMPs. From this study, we conclude that Phyllanthus amarus effectively modifies alcohol + thermally oxidized PUFA-induced fibrosis.

Triplex forming oligonucleotides against type α1(I) collagen attenuates liver fibrosis induced by bile duct ligation

Liver fibrosis is a consequence of chronic liver disorders which lead to the accumulation of extracellular matrix (ECM). Particularly, there is an increased accumulation of collagen in the fibrotic liver. We have therefore used a triplex forming oligonucleotide (TFO) against the type α1(I) collagen and evaluated, whether it can attenuate liver fibrosis induced by common bile duct ligation (CBDL) in rats. There was a significant decrease in hydroxyproline levels and Masson's trichrome staining for collagen in TFO-treated CBDL groups compared to non-treated CBDL group. There was over expression of type α1(I) collagen, α-smooth muscle actin (α-SMA) and TGF-β1 expression in the CBDL group compared to TFO-treated CBDL group. Also, the serum alanine transaminase (ALT) and aspartate transaminase (AST) concentrations were less in the TFO treated group compared to non-treated CBDL group. There was also less neutrophils accumulation in TFO treated CBDL group assayed by myeloperoxidase (MPO) assay. These results suggests that TFO can be used to downregulate type 1 collagen gene expression and can alleviate liver fibrosis induced by common bile duct ligation.

The multifaceted role of pirfenidone and its novel targets

BACKGROUND

Pirfenidone (PFD) is a molecule that exhibits antifibrotic properties in a variety of in vitro and animal models of lung, liver and renal fibrosis. These pathologies share many fibrogenic pathways with an abnormal fibrous wound-healing process; consequently, tissue repair and tissue regeneration-regulating mechanisms are altered.

OBJECTIVE

To investigate the usefulness of PFD as an antifibrotic agent in clinical and experimental models of fibrotic disease.

CONCLUSIONS

There is a growing understanding of the molecular effects of PFD on the wound healing mechanism, leading to novel approaches for the management of fibrosis in lung, liver and renal tissues. Although the optimum treatment for fibrosis remains undefined, it is possible that combined therapeutic regimens that include this wide-application molecule, pirfenidone, could offer a useful treatment for fibrotic disease.

Investigational approaches to therapies for idiopathic pulmonary fibrosis

IMPORTANCE OF THE FIELD

In fibrosing diseases, scar tissue begins to replace normal tissue, causing tissue dysfunction. For instance, in lung fibrosis, foci of what resembles scar tissue form in the lungs, impeding the ability of patients to breathe. These conditions represent a significant source of morbidity and mortality. More than 150,000 people in the USA have some form of fibrotic lung disease, and the 5-year mortality rate for these diseases can be as high as 80%. Despite this large unmet medical need, there are no FDA-approved therapies. Although our understanding of the causes and the biology of fibrosing diseases remains relatively poor, we have made impressive advances in identifying the major cell populations and many biochemical mediators that can drive this process. As a result, novel therapeutics are being developed based upon these discoveries.

AREAS COVERED IN THIS REVIEW

This review examines the experimental therapies currently under investigation as of late 2009 for a major class of lung fibrosis called idiopathic pulmonary fibrosis (IPF).

WHAT THE READER WILL GAIN

The reader will gain an overview of current experimental therapies for IPF.

TAKE HOME MESSAGE

With the recent approval of Pirfenidone in Japan for use in IPF, and a rich pipeline of experimental therapies in various stages of clinical development, the future looks bright for new treatment options.

Fluorofenidone attenuates collagen I and transforming growth factor-beta1 expression through a nicotinamide adenine dinucleotide phosphate oxidase-dependent way in NRK-52E cells

AIM

Fluorofenidone (1-(3-fluorophenyl)-5-methyl-2-(1H)-pyridone) is a novel pyridone agent. The aim of the present study is to investigate the effects of fluorofenidone on angiotensin (Ang)II-induced fibrosis and the involved molecular mechanism in rat proximal tubular epithelial cells.

METHODS

NRK-52E cells, a rat proximal tubular epithelial cell line, were incubated with medium containing AngII, with or without nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor diphenylene iodonium (DPI), losartan, fluorofenidone (2, 4 and 8 mmol/L) and pirfenidone (8 mmol/L) for 24 h. Cells in the serum-free medium were controls. The expression of three subunits of NADPH oxidase, including p47phox, Nox-4 and p22phox, were determined by real-time reverse transcription polymerase chain reaction (RT-PCR) and western blot. NADPH oxidase activity was measured directly by superoxide dismutase (SOD) inhibitable cytochrome C reduction assay. The generation of reactive oxygen species (ROS) was measured by dichlorofluorescein fluorescence analysis. The mRNA and protein expression of collagen I and transforming growth factor (TGF)-beta1 were determined by real-time RT-PCR and enzyme-linked immunosorbent assay.

RESULTS

Fluorofenidone significantly inhibited TGF-beta1 and collagen I expression upregulation induced by AngII or TGF-beta1 respectively. Moreover, fluorofenidone greatly reduced the elevation of expression and activity of NADPH oxidase and inhibited ROS generation induced by AngII in rat proximal tubular epithelial cells. These responses were also attenuated by DPI, losartan, and pirfenidone.

CONCLUSION

Fluorofenidone acted as an anti-oxidative and anti-fibrotic agent through the mechanisms of blocking NADPH oxidase-dependent oxidative stress and inhibiting TGF-beta1 expression in rat proximal tubular epithelial cells.

Pirfenidone inhibits carbon tetrachloride- and albumin complex-induced liver fibrosis in rodents by preventing activation of hepatic stellate cells

1. Pirfenidone (PFD; 5-methyl-1-phenyl-2(1H)-pyridone) is an effective and novel agent with antifibrotic and anti-inflammatory properties. In the present study, we investigated the antifibrotic effects of PFD on experimental liver fibrosis models in rodents and the possible underlying molecular mechanisms. 2. Liver fibrosis was induced by carbon tetrachloride (CCl(4)) in BALB/c mice. Pirfenidone (250 mg/kg) and silymarin (50 mg/kg) were given to different groups of rats by gastric gavage for 4 weeks. Pirfenidone significantly attenuated fibrosis severity, as determined by histopathological scores and hydroxyproline levels in liver tissue, by 49.8 and 44.9%, respectively, compared with the CCl(4)-treated group. The antifibrotic effects of PFD were significantly greater than those of silymarin, as indicated by a decrease of 23.5 and 24.8% in histopathological scores and hydroxyproline levels, respectively. 3. Liver fibrosis was also induced by albumin antigen-antibody complex in Wistar rats, which were then treated with the same doses of PFD and silymarin for 8 weeks. Pirfenidone significantly reduced the degree of fibrosis compared with CCl(4)-treated rats (by 45.0 and 51.0% as determined by histopathological scores and hydroxyproline levels in liver tissue, respectively). The antifibrotic effects of PFD were comparable to those of silymarin. 4. The effects of PFD on the expression of extracellular matrix-associated genes in human hepatic stellate cells (the LX-2 cell line) were measured by real-time quantitative polymerase chain reaction. LX-2 cells were treated with or without 100 micromol/L or 1 mmol/L PFD for 24 h. Pirfenidone significantly inhibited the expression of a-smooth muscle actin and Type I collagen in 8 ng/mL transforming growth factor-beta1- or 5% fetal bovine serum-activated LX-2 cells in a dose-dependent manner. 5. In conclusion, the results of the present study demonstrate that PFD is effective in ameliorating fibrogenesis induced by CCl(4) in mice and by the albumin complex in rats. These effects were mediated mainly via inhibition of the activation of hepatic stellate cells, as well as antifibrotic actions (i.e. inhibition of collagen synthesis) of PFD.