Pirfenidone attenuates ischaemia-reperfusion injury in the rat small intestine

Pirfenidone ameliorates ANIT-induced cholestatic liver injury via modulation of FXR, NF-кB/TNF-α, and Wnt/GSK-3β/β-catenin signaling pathways

Cholestasis is a hepatobiliary disorder characterized by the excessive accumulation of toxic bile acids in hepatocytes, leading to cholestatic liver injury (CLI) through multiple pathogenic inflammatory pathways. Currently, there are limited therapeutic options for the management of cholestasis and associated CLI; therefore, new options are urgently needed. Pirfenidone (PF), an oral bioavailable pyridone analog, is used for the treatment of idiopathic pulmonary fibrosis. PF has recently demonstrated diverse potential therapeutic activities against different pathologies. Accordingly, the present study adopted the α-naphthyl isothiocyanate (ANIT)-induced CLI model in mice to explore the potential protective impact of PF and investigate the underlying mechanisms of action. PF intervention markedly reduced the serum levels of ALT, AST, LDH, total bilirubin, and total bile acids, which was accompanied by a remarkable amelioration of histopathological lesions induced by ANIT. PF also protected the mice against ANIT-induced redox imbalance in the liver, represented by reduced MDA levels and elevated GSH and SOD activities. Mechanistically, PF inhibited ANIT-induced downregulated expressions of the farnesoid X receptor (FXR), as well as the bile salt export pump (BSEP) and the multidrug resistance-associated protein 2 (MRP2) bile acid efflux channels. PF further repressed ANIT-induced NF-κB activation and TNF-α and IL-6 production. These beneficial effects were associated with its ability to dose-dependently inhibit Wnt/GSK-3β/β-catenin/cyclin D1 signaling. Collectively, PF protects against ANIT-induced CLI in mice, demonstrating powerful antioxidant and anti-inflammatory activities as well as an ability to oppose BA homeostasis disorder. These protective effects are primarily mediated by modulating the interplay between FXR, NF-κB/TNF-α/IL-6, and Wnt/β-catenin signaling pathways.

The effects of pirfenidone on ischaemia-reperfusion injury in testicular torsion-induced rat model

The aim of this study was to analyse the effect of pirfenidone against ischaemia-reperfusion injury occurring after detorsion in rats with induced testicular torsion model. Group 1 was assigned as the control group. Group 2 first had testis torsion performed, and then, testicular detorsion was performed. Group 3 had similar procedures to the rats in Group 2. Rats in Group 3 additionally had 325 mg/kg pirfenidone administered immediately after ischaemia. The blood samples were analysed spectrophotometrically. To determine the intensity of tissue injury, haemorrhage, oedema and congestion levels were evaluated with direct microscopic investigation of testis. Seminiferous tubule architecture, spermatogenesis processes and germ cell maturation were graded by Johnsen and Cosentino scoring systems. In Group 3, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities increased compared with Group 2 (p:.03 and p:.049 respectively). Additionally, the mean malondialdehyde (MDA) value was higher in Group 2 compared with the other groups (p:.001). Histopathological investigation of rats in Group 3 identified positive changes in haemorrhage, oedema and congestion levels compared with Group 2 (p:.031, p:.048, p:.044 respectively). Similarly, Johnsen and Cosentino scores were positively affected in Group 3 (p:.033, p:.032 respectively). Pirfenidone is protective against testicular oxidative damage.

Pirfenidone alleviates lung ischemia-reperfusion injury in a rat model

OBJECTIVE

Lung ischemia-reperfusion injury is among the complications seen after lung transplantation, resulting in morbidity and mortality. Pirfenidone, an antifibrotic agent for the treatment of idiopathic pulmonary fibrosis, is reported to have cytoprotective properties in various disease models. The purpose of this study was to investigate the effect of pirfenidone on lung ischemia-reperfusion injury.

METHODS

Male Lewis rats (260-290 g) were divided into 3 groups: sham group (n = 5), warm ischemia (WI) group (n = 10), and WI plus pirfenidone (WI+PFD) group (n = 10). The sham group underwent 210 minutes of perfusion without ischemia. The WI and WI+PFD groups underwent 90 minutes of warm ischemia and 120 minutes of reperfusion. In the WI+PFD group, pirfenidone (300 mg/kg) was administered orally by gavage 30 minutes before ischemia. After reperfusion, arterial blood gas analysis, lung mechanics, lung wet-to-dry weight ratio, and histologic findings were obtained. The gene expressions of proinflammatory cytokines in lung tissue were measured by quantitative reverse transcription polymerase chain reaction.

RESULTS

Compared with the WI group, the WI+PFD group had significantly better dynamic pulmonary compliance (P < .01) and oxygenation levels (P < .05). The wet-to-dry ratio was lower in the WI+PFD group (P < .05). Histologic analysis showed that the WI+PFD group had reduced perivascular edema and neutrophil infiltration. The expression of tumor necrosis factor-α messenger RNA was decreased in the WI+PFD group (P < .05).

CONCLUSIONS

Our results revealed that in a rat hilar clamp model, pirfenidone alleviated lung ischemia-reperfusion through anti-inflammatory effects.

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.

Function and expression of cystic fibrosis transmembrane conductance regulator after small intestinal transplantation in mice

The secretion function of intestinal graft is one of the most important factors for successful intestinal transplantation. Cystic fibrosis transmembrane conductance regulator (CFTR) mediates HCO₃^- and Cl^- secretions in intestinal epithelial cells. In this study, we made investigation on the expression and function of CFTR in an experimental model of murine small intestinal transplantation. Heterotopic intestinal transplantations were performed in syngeneic mice. The mRNA and protein expressions of CFTR were analyzed by real time PCR and western blot. Murine intestinal mucosal HCO₃^- and Cl^- secretions were examined in vitro in Ussing chambers by the pH stat and short circuit current (I_sc) techniques. The results showed that forskolin, an activator of CFTR, stimulated jejunal mucosal epithelial HCO₃^- and Cl^- secretions in mice, but forskolin-stimulated HCO₃^- and Cl^- secretions in donor and recipient jejunal mucosae of mice after heterotopic jejunal transplantation were markedly decreased, compared with controls (P<0.001). The mRNA and protein expression levels of CFTR in donor and recipient jejunal mucosae of mice were also markedly lower than those in controls (P<0.001), and the mRNA and protein expression levels of tumor necrosis factor α (TNFα) were markedly increased in donor jejunal mucosae of mice (P<0.001), compared with controls. Further experiments showed that TNFα down-regulated the expression of CFTR mRNA in murine jejunal mucosa. In conclusion, after intestinal transplantation, the function of CFTR was impaired, and its mRNA and protein expressions were down-regulated, which may be induced by TNFα.

Pirfenidone treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a discrete clinicopathologic entity defined by the presence of usual interstitial pneumonia on high-resolution CT scan and/or open lung biopsy and the absence of an alternate diagnosis or exposure explaining these findings. There are currently no FDA-approved therapies available to treat this disease, and the 5-year mortality is ∼80%. The pyridone derivative pirfenidone has been studied extensively as a possible therapeutic agent for use in this deadly disease. This review will present the unique clinical features and management issues encountered by physicians caring for IPF patients, including the poor response to conventional therapy. The biochemistry and preclinical efficacy of pirfenidone will be discussed along with a comprehensive review of the clinical efficacy, safety, and side effects and patient-centered foci such as quality of life and tolerability. It is hoped that this information will lend insight into the complex issues surrounding the use of pirfenidone in IPF and lead to further investigation of this agent as a possible therapy in this devastating disease.

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.

Resveratrol, a natural antioxidant, attenuates intestinal ischemia/reperfusion injury in rats

The intestine is highly susceptible to ischemia/reperfusion (I/R) injury. Splanchnic ischemia is the initial event that releases injurious factors, leading to systemic disorders with high morbidity and mortality. Oxidative stress mediators are believed to contribute to the intestinal I/R injury. Resveratrol, a polyphenol found in grapes, is shown to be a strong antioxidant in various tissues, with a property of an estrogen-receptor agonist. Therefore, we investigated the effects of resveratrol on oxidative injury in the intestine. Female Wistar rats were randomly allocated into four groups (n = 8, each). The sham group was only subjected to surgical procedures, while other animals were subjected to intestinal ischemia (60 min) and subsequent reperfusion (60 min). One group received resveratrol (15 mg/kg, 0.3 ml/day intraperitoneally) for both 5 days before surgery and 15 min before ischemia, while the other was treated intraperitoneally with 0.5% ethyl alcohol as vehicle (0.3 ml/day). In the I/R rat intestines, we detected severe tissue injuries (p < 0.001), the significant increases in the tissue levels of malondialdehyde (MDA), nitric oxide (NO), and myeloperoxidase (MPO) (p < 0.001), and the decrease in superoxide dismutase (SOD) activity (p < 0.001), compared to the sham control. Resveratrol significantly ameliorated the intestinal injury, decreased MDA, NO and MPO levels to the sham control levels, and decreased bacterial translocation in mesentery lymph nodes, liver and spleen (p < 0.001). Resveratrol also restored the SOD activity. These results suggest that resveratrol could protect intestinal tissue against I/R injury with its potent antioxidant properties.

The protective effect of methylene blue in lungs, small bowel and kidney after intestinal ischemia and reperfusion

PURPOSE

To study the role of methylene blue as an inhibitor of superoxide production by xanthine oxidase.

METHODS

Thirty-two Wistar rats were divided into 2 groups of 16 animals: the control group and the experimental group. All were submitted to a laparotomy for the occlusion of the cranial mesenteric artery during 60 minutes. The reperfusion was confirmed by the pulsation of the artery after the release of the temporary ligature and color change of the intestines. In the animals of the control group, 2 ml of saline were injected in the peritoneal cavity and in the animals of the experimental group, 2 ml of methylene blue were injected in the peritoneal cavity. After reperfusion for 4 hours, the animals were then sacrificed. The lungs were excised from all 32 rats. Simultaneously, the small intestine and kidneys were ressected in 20 animals (10 from the control group and 10 from the experimental group). Samples of the organs were taken to evaluate the action of xanthine-oxidase, for histopathology studies and for characterization of the edema.

RESULTS

In the animals of the experimental group, the inflammatory lesion as well as the edema in the lung was greater than in the control group. The intestinal and renal lesions were similar in both groups, but the lung damage was superior to that observed in the intestines and kidneys. .

CONCLUSION

Despite similar action of the xanthine oxidase in the control and the experimental group, after intestinal ischemia and reperfusion, the protective effect of methylene blue was observed only in the lungs of the experimental group.

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.

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.

Protective effects of ascorbic acid pretreatment in a rat model of intestinal ischemia-reperfusion injury: a histomorphometric study

BACKGROUND

Ascorbic acid has shown promise in attenuation of intestinal ischemia-reperfusion (I/R) injury. The aim of this study was to determine the protective effects of ascorbic acid on intestinal morphology during IR injury in rats.

MATERIALS AND METHODS

We examined morphological changes in the small intestine of Wistar rats after (i) 40 minutes of ischemia (I), (ii) ischemia followed by 30 min of reperfusion (IR), (iii) ischemia with ascorbic acid (IA), (iv) ischemia followed by reperfusion and ascorbic acid (IRA) and (v) in a sham group (S). We used morphometry to evaluate the amount of villous architecture, crypts, necrosis, hemorrhagic infarcts and inflammatory cells at the mesenteric and antimesenteric borders of the small intestine.

RESULTS

Ascorbic acid caused a significant reduction of antimesenteric villous hemorrhagic infarction (p<0.05) of the small intestine after ischemia followed by reperfusion as well as villous necrosis reduction at both borders after ischemia (p<0.05). The lesions found in the small intestine were more prominent along the antimesenteric margin.

CONCLUSIONS

Ascorbic acid pretreatment has a protective effect against the intestinal morphological lesions induced by ischemia-reperfusion injury in rats.

Effects of ischemia-reperfusion on the absorption and esterase metabolism of diltiazem in rat intestine

Intestinal ischemia-reperfusion (I/R) is a serious clinical condition that triggers a complex inflammatory response. Inflammatory processes affect some enzymatic systems related to intestinal drug metabolism and bioavailability. Diltiazem (DTZ) is a calcium channel blocker, which is extensively metabolised in the intestine by esterases and different CYP450 isoforms. The main biotransformation pathway of DTZ in rats is desacetylation by esterases. This study analysed the effect of I/R on intestinal absorption and metabolism of DTZ, focusing on esterase activity, through different methodologies, after 60 min of superior mesenteric artery occlusion and 30 min of reperfusion or sham surgical procedures. The rate of DTZ appearance in blood during in situ studies increased significantly in the I/R group (0.094+/-0.014 10(-5) cm/s vs 0.271+/-0.110 10(-5) cm/s) and the calculated metabolised fraction of DTZ decreased significantly, showing an important reduction in the desacetylase activity in the I/R group. These results were supported by microsomal incubations, where desacetylase activity was related to esterases by specific inhibition, using paraoxon and bis-nitrophenylphosphate, and also by studies in everted rings. DTZ metabolism was higher in the jejunum than in the ileum, the esterase activity being affected by I/R in both regions. The present findings suggest that I/R injury clearly affects the esterases' activity and modifies the amount of DTZ and its metabolites in blood during in situ perfusion. This modification of intestinal esterase activity could be important for the pharmacokinetic behaviour of other drugs and prodrugs after intestinal pathologies involving inflammation and oxidative stress.

Pirfenidone modulates airway responsiveness, inflammation, and remodeling after repeated challenge

We investigated the therapeutic potential of a newly developed antifibrotic agent, pirfenidone, to regulate airway remodeling and the development of allergic airway inflammation and airway hyperresponsiveness after chronic allergen challenge. Administration of pirfenidone after sensitization but during the period of ovalbumin challenge significantly prevented the development of airway hyperresponsiveness and prevented eosinophil and lymphocyte accumulation in the airways. IL-4, IL-5, and IL-13 levels in bronchoalveolar lavage fluid and ovalbumin-specific serum IgE antibody levels were also significantly reduced. Treatment with pirfenidone significantly reduced transforming growth factor-beta1 and platelet-derived growth factor levels in bronchoalveolar lavage fluid. Pirfenidone reduced the expression of transforming growth factor-beta1, the development of goblet cell hyperplasia and subepithelial collagenization, and the increases in contractile elements in the lung. These data indicate that pirfenidone may play an important role in the treatment of asthma and has the potential reduce or prevent airway remodeling.

Pirfenidone and candesartan ameliorate morphological damage in mild chronic anti-GBM nephritis in rats

BACKGROUND

The antifibrotic substance pirfenidone and the angiotensin II type I receptor antagonist candesartan cilexetil, given alone and in combination, were tested in rats with chronic anti-glomerular basement membrane glomerulonephritis (anti-GBM GN).

METHODS

Male Wistar rats with anti-GBM GN were treated for 8 weeks with candesartan (4 mg/kg body weight/day), pirfenidone (500 mg/kg body weight/day) or a combination of both drugs. One GN group received no treatment and untreated non-GN-rats were used as controls. Blood pressure and urinary protein excretion were measured after 3 and 7 weeks. Kidney histology was complemented by ultrastructural investigation and by quantification of collagen Ialpha mRNA.

RESULTS

The percentage of glomeruli with adsorption droplets in podocytes correlated well with the amount of proteinuria (r = 0.873, P<0.01) and was significantly lowered in rats treated with candesartan (8.3 vs GN 24.6%), pirfenidone (9.8%) and combined treatment (2.6%, P<0.05 vs candesartan alone). A comparable lowering was seen for segmental sclerosis (GN 11%, candesartan 0.7%, P<0.05 vs GN, pirfenidone 1.8%, P = 0.09 vs GN, candesartan/pirfenidone 0.1%, P>0.5 vs candesartan alone). Cortical collagen Ialpha mRNA expression was significantly decreased in all treatment groups. Ultrastructural investigation showed an amelioration of basement membrane alterations and podocyte damage in the treatment groups. Candesartan caused significant blood pressure reduction and the effect was significantly enhanced by combination therapy after 3 weeks. Rats treated with pirfenidone showed blood pressure values similar to control rats.

CONCLUSION

Pirfenidone has a beneficial effect on morphological changes in anti-GBM GN comparable with candesartan although with a trend to slightly better results with candesartan treatment. Moreover, our results suggest an additive effect of combination treatment.

Pirfenidone protects endotoxin-induced liver injury after hepatic ischemia in rats

BACKGROUND

Pirfenidone (PFD), an experimental antifibrotic agent, was investigated for its effects on endotoxin-induced liver injury after hepatic ischemia-reperfusion.

METHODS

Male Sprague-Dawley rats were subjected to 30 minutes of partial hepatic ischemia, followed by reperfusion for 24 hours. Lipopolysaccharide (LPS) was injected at 30 minutes of reperfusion. PFD (300 mg/kg) or its vehicle (0.5% carboxymethylcellulose) was given orally following LPS administration.

RESULTS

PFD prevented the increase in activities of serum alanine transaminase, aspartate transaminase, and lactate dehydrogenase after reperfusion. PFD inhibited the increase of cytokine-induced neutrophil chemoattractant in serum and liver tissue. The number of neutrophils infiltrating the liver was significantly lower in the PFD-treated group than the control group.

CONCLUSION

These results indicate that PFD prevents endotoxin-induced liver injury after hepatic ischemia-reperfusion, in part through the decrease of neutrophil infiltration to the liver.

Comparative protection against rat intestinal reperfusion injury by a new inhibitor of sPLA2, COX-1 and COX-2 selective inhibitors, and an LTC4 receptor antagonist

(1) A new group IIa sPLA2 inhibitor was compared with selective inhibitors of COX-1, COX-2 and an LTC4 antagonist for effects on local and remote tissue injuries following ischaemia and reperfusion (I/R) of the small intestine in rats. (2) In an acute model of ischaemia (30 min) and reperfusion (150 min) injury in the absence of inhibitors, there was significant intestinal haemorrhage, oedema and mucosal damage, neutropenia, elevated serum levels of aspartate aminotransferase (AST) and hypotension. (3) Preischaemic treatment with the inhibitor of sPLA2 (Group IIa), at 5 mg kg-1 i.v. or 10 mg kg-1 p.o. significantly inhibited I/R-induced neutropenia, the elevation of serum levels of AST, intestinal oedema and hypotension. (4) Pretreatment with the COX-2 inhibitor celebrex (10 mg kg-1 i.v.) and the LTC4 antagonist zafirlukast (1 mg kg-1 i.v.) also showed marked improvement with I/R-induced AST, oedema and neutropenia. Hypotension was only reduced by the LTC4 antagonist. The COX-1 inhibitor flunixin (1 mg kg-1 i.v.) did not effect improvement in the markers of tissue injury. (5) Histological examination of rat I/R injury showed that all of the drugs offered some protection to the mucosal layer damage compared to no drug treatment. Given i.v., the sPLA2 inhibitor was more effective than either the COX-1 or COX-2 inhibitors in preventing rat I/R injury. (6) These results indicate that a potent new inhibitor of sPLA2 (group IIa) protects the rat small intestine from I/R injury after oral or intravenous administration. COX-2 and LTC4 inhibitors also showed some beneficial effects against intestinal I/R injury. Our study suggests that sPLA2 (Group IIa) may have a pathogenic role in intestinal I/R in rats.