Pirfenidone: anti-fibrotic agent with a potential therapeutic role in the management of transplantation patients

Antifibrotic drugs in lung transplantation and chronic lung allograft dysfunction: a review

This review aims to provide an overview of pre-transplant antifibrotic therapy on peri-transplant outcomes and to address the possible role of antifibrotics in lung transplant recipients with chronic lung allograft dysfunction.Lung transplantation is an established treatment modality for patients with various end-stage lung diseases, of which idiopathic pulmonary fibrosis and other progressive fibrosing interstitial lung diseases are growing indications. Theoretically, widespread use of antifibrotics prior to lung transplantation may increase the risk of bronchial anastomotic complications and impaired wound healing.Long-term graft and patient survival are still hampered by development of chronic lung allograft dysfunction, on which antifibrotics may have a beneficial impact.Antifibrotics until the moment of lung transplantation proved to be safe, without increasing peri-transplant complications. Currently, best practice is to continue antifibrotics until time of transplantation. In a large multicentre randomised trial, pirfenidone did not appear to have a beneficial effect on lung function decline in established bronchiolitis obliterans syndrome. The results of antifibrotic therapy in restrictive allograft syndrome are eagerly awaited, but nonrandomised data from small case reports/series are promising.

Pirfenidone regulates LPS mediated activation of neutrophils

Excessive inflammation or its absence may result in impaired wound healing. Neutrophils are among the first innate immune cells to arrive at the injury site. They participate in infection control and debris removal to initiate healing. If not timely resolved, neutrophils can cause excessive tissue inflammation and damage. Drugs with anti-inflammatory and anti-fibrotic effects are of promise for improving healing by balancing the primary defensive functions and excessive tissue damage actions. Of interest, pirfenidone (Pf), an FDA approved anti-fibrotic drug to treat idiopathic pulmonary fibrosis, has been shown to ameliorate inflammation in several animal models including mouse deep partial-thickness burn wounds. However, there is a lack of mechanistic insights into Pf drug action on inflammatory cells such as neutrophils. Here, we examined the treatment effects of Pf on LPS-stimulated neutrophils as a model of non-sterile inflammation. Firstly, Pf reduced chemotaxis and production of pro-inflammatory ROS, cytokines, and chemokines by LPS-activated neutrophils. Secondly, Pf increased anti-inflammatory IL-1RA and reduced neutrophil degranulation, phagocytosis, and NETosis. Thirdly, Pf affected downstream signaling kinases which might directly or indirectly influence neutrophil responses to LPS. In conclusion, the results suggest that Pf lessens the inflammatory phenotypes of LPS-activated neutrophils.

Distinct improvement of pulmonary function, ground-glass opacity, hypoxia and physical findings in an idiopathic pulmonary fibrosis patient after pirfenidone treatment : a case report with a review of the literature

Background : Pirfenidone (PFD), an anti-fibrosis drug for idiopathic pulmonary fibrosis (IPF), suppresses disease progression and delays decline of forced vital capacity. However, this drug rarely makes marked improvement of pulmonary function, chest high-resolution computed tomography (HRCT) findings and hypoxia. Case presentation : A 59 year-old-man, who was a former smoker and had a history of alcoholic liver cirrhosis, developed exertional dyspnea and was referred to our hospital. HRCT showed honeycomb changes with surrounding ground-glass opacity (GGO) in a predominantly basal and subpleural distribution. He was diagnosed with IPF and the treatment with PFD was started. At 16 months after the start of treatment, the predicted forced vital capacity value markedly improved from 82.9% to 98.6%. His resting-state partial pressure of arterial oxygen while breathing room air increased from a minimum of 54.7 mmHg (at 2 months treatment) to 72.5 mmHg. The GGO observed at diagnosis disappeared in HRCT. But after 32 months of treatment, his general condition got worse gradually, and he died from chronic progression of IPF after 48 months of treatment. Conclusion : Our case suggests that a complication of chronic liver disease and the existence of GGO may be characteristics of super-responder to PFD treatment for IPF patients. J. Med. Invest. 67 : 358-361, August, 2020.

Copper-Catalyzed N-Arylation of 2-Pyridones Employing Diaryliodonium Salts at Room Temperature

A new and mild synthetic approach for the N-arylation of 2-pyridones with diaryliodonium salts has been developed. Most reactions proceed readily at room temperature in the presence of 10 mol % of copper chloride. As a result, a wide range of N-arylpyridine-2-ones were synthesized in yields of 23% to 99%. With this method, an antifibrotic drug, Pirfenidone, was successfully synthesized in 99% yield within 30 min at room temperature.

A Patient with Idiopathic Pleuroparenchymal Fibroelastosis Showing a Sustained Pulmonary Function due to Treatment with Pirfenidone

The patient was a 68-year-old man presenting with body weight loss and exertional dyspnea. High-resolution computed tomography of the chest showed dense subpleural consolidation with traction bronchiectasis and volume loss predominantly in bilateral apical lesions and upper lobes. A histopathological analysis of a specimen of the right upper lobe showed histological patterns which were consistent with idiopathic pleuroparenchymal fibroelastotis (IPPFE). Treatment with pirfenidone was introduced with the expectation of its potential benefit. The effect of pirfenidone was satisfactory, and a decline in forced vital capacity was inhibited during treatment. This is the first case report suggesting the efficacy of pirfenidone for patients with IPPFE.

Idiopathic pleuroparenchymal fibroelastosis is characterized by an elevated serum level of surfactant protein-D, but Not Krebs von den Lungen-6

PURPOSE

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a recently reported rare disease entity characterized by fibrotic thickening of the pleural and subpleural parenchyma predominantly in the upper lobes in idiopathic interstitial pneumonias (IIPs). Because the clinical features of this rare disease are not fully elucidated, we examined the clinical characteristics of IPPFE, especially for serum interstitial biomarkers, surfactant protein-D (SP-D), and Krebs von den Lungen-6 (KL-6).

METHODS AND RESULTS

Four consecutive cases of IPPFE who fulfilled the diagnostic criteria were studied. All cases were more than 60 years of age, and were classified as underweight by body mass index. A severe restrictive ventilatory defect was found in all cases on admission. High-resolution computed tomography showed intense pleural thickening associated with fibrosis predominant in upper lobes. Histopathological findings were also confirmed in three out of four cases. Interestingly, the serum level of SP-D was markedly elevated in all cases, while KL-6 was within normal range in three out of four cases. As compared with major IIPs such as idiopathic pulmonary fibrosis and fibrotic nonspecific interstitial pneumonia, IPPFE significantly showed higher frequency of cases with a unique pattern of serum biomarkers, which is characterized by an elevated level of SP-D with a normal range of KL-6.

CONCLUSIONS

In IPPFE, SP-D might tend to be elevated, while KL-6 was within a normal range. Further study is required to determine the pathogenesis and clinical significance of the elevated SP-D in IPPFE.

Idiopathic pleuroparenchymal fibroelastosis: consideration of a clinicopathological entity in a series of Japanese patients

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a recently reported group of disorders characterized by fibrotic thickening of the pleural and subpleural parenchyma predominantly in the upper lobes. We report five Japanese cases fulfilling the criteria of IPPFE and address whether it should be considered a separate clinicopathologic entity. And this study was an attempt to identify features in common between IPPFE and previously described idiopathic upper lobe fibrosis (IPUF), allowing IPPFE to be considered as a distinct entity in our Japanese series.

METHODS

Five consecutive cases of idiopathic interstitial lung disease confirmed as IPPFE by surgical lung biopsy were studied.

RESULTS

There were four males and one female, aged 70±2.76 yr. No associated disorder or presumed cause was found in any case. Lung function tests found a restrictive ventilatory defect (4/5) and/or impairment of DLco (4/5). Chest X-ray showed marked apical pleural thickening in all cases. Computed tomography of the chest in all cases mainly showed intense pleural thickening and volume loss associated with evidence of fibrosis, predominantly in the upper lobes. In all cases in this study, markedly thickened visceral pleura and prominent subpleural fibrosis characterized by both elastic tissue and dense collagen were clearly shown. All cases were alive at the last follow-up, 17.6±13.59 months after diagnosis; however, all had deteriorated both clinically and radiologically.

CONCLUSIONS

IPPFE deserves to be defined as a separate, original clinicopathologic entity owing to its uniformity and IPPFE has some features in common with previously described idiopathic upper lobe fibrosis (IPUF). Our limited experience with a cohort of 5 subjects suggests that IPPFE can be rapidly progressive.

The antifibrotic agent pirfenidone inhibits angiotensin II-induced cardiac hypertrophy in mice

Pirfenidone (5-methyl-1-phenyl-2-[(1)H]-pyridone) is an effective drug for idiopathic interstitial pneumonia that can prevent and reverse tissue fibrosis in several organs. Therefore, we investigated whether pirfenidone has a potential role in preventing angiotensin II (Ang II)-induced cardiac hypertrophy. A cardiac hypertrophic mouse model was created using an Ang II infusion (200 ng kg(-1) min(-1)) in wild-type mice for 2 weeks. Mice were divided into the following three groups: a saline-infused (control) group, an Ang II infusion (vehicle) group and an Ang II infusion+pirfenidone-treated (PFD) group, which received pirfenidone (300 mg kg(-1) per day) by gastric gavage during the Ang II infusion. At 2 weeks, we assessed hemodynamics and cardiac function and investigated tissue fibrosis of the myocardium histologically and genetically. Blood pressure in the vehicle group was significantly increased compared to the control group. Although blood pressure was not different between the vehicle and PFD groups, heart weight was significantly decreased in the PFD group. Echocardiography revealed that left ventricular hypertrophy was significantly increased in the vehicle group vs. the control group. Interestingly, pirfenidone significantly inhibited this effect. Continuous infusion of Ang II increased the perivascular and interstitial tissue fibrosis, and pirfenidone inhibited these fibrotic changes. Pirfenidone also inhibited Ang II-induced hypertrophy. In the vehicle group, the mRNA expressions of atrial natriuretic peptide, brain natriuretic peptide and transforming growth factor-β1 were increased, which was significantly inhibited by pirfenidone. Furthermore, the expression of mineralocorticoid receptors was attenuated by pirfenidone. These results indicate that pirfenidone might be effective as an antifibrotic drug in the treatment of cardiac hypertrophy induced by hypertension.

Pirfenidone: an anti-fibrotic therapy for progressive kidney disease

IMPORTANCE OF THE FIELD

Many chronic diseases of various etiologies lead to fibrosis and organ dysfunction. Despite many advances in medicine in recent years, options to slow the progression of fibrotic diseases have remained limited. The recent availability of pirfenidone, an antifibrotic and anti-inflammatory investigational agent, thus offers a new hope for treating progressive fibrotic diseases.

AREAS COVERED IN THIS REVIEW

This review provides concise review of the available data regarding the mechanism and pharmacokinetics of pirfenidone and preclinical and clinical data regarding efficacy and safety in fibrotic diseases of the kidney. It also reviews results of clinical trials involving pirfenidone in other fibrotic diseases.

WHAT THE READER WILL GAIN

The review will provide in-depth review of pirfenidone with a renal focus.

TAKE HOME MESSAGE

Because many of the available clinical trials have been small and/or uncontrolled, conclusive evidence regarding efficacy and safety of pirfenidone is lacking, particularly in patients with renal or hepatic dysfunction. Larger studies are needed to better understand long-term efficacy and safety of this medication in various patient populations.

Pirfenidone inhibits T-cell activation, proliferation, cytokine and chemokine production, and host alloresponses

BACKGROUND

We previously showed that pirfenidone, an anti-fibrotic agent, reduces lung allograft injury or rejection. In this study, we tested the hypothesis that pirfenidone has immune modulating activities and evaluated its effects on the function of T-cell subsets, which play important roles in allograft rejection.

METHOD

We first evaluated whether pirfenidone alters T-cell proliferation and cytokine release in response to T-cell receptor (TCR) activation, and whether pirfenidone alters regulatory T cells (CD4CD25) suppressive effects using an in vitro assay. Additionally, pirfenidone effects on alloantigen-induced T-cell proliferation in vivo were assessed by adoptive transfer of carboxyfluorescein diacetate succinimidyl ester-labeled T cells across a parent->F1 major histocompatibility complex mismatch, as well as using a murine heterotopic cardiac allograft model (BALB/c->C57BL/6).

RESULTS

Pirfenidone was found to inhibit the responder frequency of TCR-stimulated CD4 cell total proliferation in vitro and in vivo, whereas both CD4 and CD8 proliferation index were reduced by pirfenidone. Additionally, pirfenidone inhibited TCR-induced production of multiple pro-inflammatory cytokines and chemokines. Interestingly, there was no change on transforming growth factor-beta production by purified T cells, and pirfenidone had no effect on the suppressive properties of naturally occurring regulatory T cells. Pirfenidone alone showed a small but significant (P<0.05) effect on the in vivo allogeneic response, whereas the combination of pirfenidone and low dose rapamycin had more remarkable effect in reducing the alloantigen response with prolonged graft survival.

CONCLUSION

Pirfenidone may be an important new agent in transplantation, with particular relevance to combating chronic rejection by inhibiting both fibroproliferative and alloimmune responses.

Pharmacokinetics and clinical effects of pirfenidone administered intravenously in horses

OBJECTIVE

To characterize the plasma pharmacokinetics and clinical effects of pirfenidone administered IV in healthy horses.

ANIMALS

6 adult horses.

PROCEDURES

A 15 mg/kg dose of pirfenidone was administered IV over 5 minutes. Physical variables were recorded and blood samples collected prior to infusion; 2.5 minutes after beginning infusion; at the end of infusion; and at 3, 6, 9, 12, 15, 20, 25, 30, 40, 50, 60, 75, and 90 minutes and 2, 2.5, 3, 4, 6, 8, 12, and 24 hours after completion of infusion. Plasma concentrations of pirfenidone and its metabolites were determined.

RESULTS

Mild clinical effects, including tachycardia and muscle fasciculations, were observed during drug administration but stopped at the end of the infusion. Pirfenidone and 2 metabolites, hydroxypirfenidone and carboxypirfenidone, were detected by the end of the 5-minute infusion. Mean peak plasma concentration of pirfenidone was 182.5 micromol/L, detected at the end of the infusion. Mean peak plasma concentrations of hydroxypirfenidone and carboxypirfenidone were 1.07 and 3.4 micromol/L, respectively, at 40 minutes after infusion. No parent drug or metabolites were detected at 24 hours. Distribution of pirfenidone best fit a 2-compartment model, and the drug had mean +/- SEM elimination half-life of 86.0 +/- 4.7 minutes, mean body clearance of 6.54 +/- 0.45 mL/kg/min, and apparent volume of distribution at steady state of 0.791 +/- 0.056 L/kg.

CONCLUSIONS AND CLINICAL RELEVANCE

Intravenous administration of pirfenidone was tolerated with transient adverse affects during infusion, and drug clearance was rapid.

Liver fibrosis

Liver damage leads to an inflammatory response and to the activation and proliferation of mesenchymal cell populations within the liver which remodel the extracellular matrix as part of an orchestrated wound-healing response. Chronic damage results in a progressive accumulation of scarring proteins (fibrosis) that, with increasing severity, alters tissue structure and function, leading to cirrhosis and liver failure. Efforts to modulate the fibrogenesis process have focused on understanding the biology of the heterogeneous liver fibroblast populations. The fibroblasts are derived from sources within and out with the liver. Fibroblasts expressing alpha-smooth muscle actin (myofibroblasts) may be derived from the transdifferentiation of quiescent hepatic stellate cells. Other fibroblasts emerge from the portal tracts within the liver. At least a proportion of these cells in diseased liver originate from the bone marrow. In addition, fibrogenic fibroblasts may also be generated through liver epithelial (hepatocyte and biliary epithelial cell)-mesenchymal transition. Whatever their origin, it is clear that fibrogenic fibroblast activity is sensitive to (and may be active in) the cytokine and chemokine profiles of liver-resident leucocytes such as macrophages. They may also be a component driving the regeneration of tissue. Understanding the complex intercellular interactions regulating liver fibrogenesis is of increasing importance in view of predicted increases in chronic liver disease and the current paucity of effective therapies.

Pirfenidone: a novel potential therapeutic agent in the management of chronic allograft rejection

Chronic allograft dysfunction is a leading cause of allograft failure, morbidity, and mortality after solid organ transplantation. The pathogenesis of chronic allograft failure has a final common pathway leading to organ fibrosis. Pirfenidone is an effective and novel antifibrotic agent with anti-inflammatory properties. Clinical use of the agent has been tested in a number of nontransplant recipients and has a favorable safety profile based on available clinical data. Building on these observations and findings, and considering the role of fibrosis in chronic allograft rejection, pirfenidone was initially investigated as adjunct therapy in a rat heterotopic tracheal transplantation model. This led to several studies confirming that pirfenidone may well be worth considering for further investigation. This paper reviews the possibility of using pirfenidone in clinical transplantation management.