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Fibrosis is the excessive deposition of extracellular matrix in an organ or tissue that results from an impaired tissue repair in response to tissue injury or chronic inflammation. The progressive nature of fibrotic diseases and limited treatment options represent significant healthcare challenges. Despite the substantial progress in understanding the mechanisms of fibrosis, a gap persists translating this knowledge into effective therapeutics. Here, we discuss the critical mediators involved in fibrosis and the role of tranilast as a potential antifibrotic drug to treat fibrotic conditions. Tranilast, an antiallergy drug, is a derivative of tryptophan and has been studied for its role in various fibrotic diseases. These include scleroderma, keloid and hypertrophic scars, liver fibrosis, renal fibrosis, cardiac fibrosis, pulmonary fibrosis, and uterine fibroids. Tranilast exerts antifibrotic effects by suppressing fibrotic pathways, including TGF-β, and MPAK. Because it disrupts fibrotic pathways and has demonstrated beneficial effects against keloid and hypertrophic scars, tranilast could be used to treat other conditions characterized by fibrosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Visceral hypersensitivity resulting from compromised gut barrier with activated immune system is a key feature of irritable bowel syndrome (IBS). Corticotropin-releasing factor (CRF) and Toll-like receptor 4 (TLR4) activate proinflammatory cytokine signaling to induce these changes, which is one of the mechanisms of IBS. As activation of the NLRP3 inflammasome by lipopolysaccharide (LPS) or TLR4 leads to release interleukin (IL)-1β, the NLRP3 inflammasome may be involved in the pathophysiology of IBS. Tranilast, an anti-allergic drug has been demonstrated to inhibit the NLRP3 inflammasome, and we evaluated the impact of tranilast on visceral hypersensitivity and colonic hyperpermeability induced by LPS or CRF (IBS rat model). Visceral pain threshold caused by colonic balloon distention was measured by monitoring abdominal muscle contractions electrophysiologically. Colonic permeability was determined by quantifying the absorbed Evans blue within the colonic tissue. Colonic protein levels of NLRP3 and IL-1β were assessed by immunoblot or ELISA. Intragastric administration of tranilast (20-200 mg/kg) for 3 days inhibited LPS (1 mg/kg)-induced visceral hypersensitivity and colonic hyperpermeability in a dose-dependent manner. Simultaneously, tranilast also abolished these alterations induced by CRF (50 µg/kg). LPS increased colonic protein levels of NLRP3 and IL-1β, and tranilast inhibited these changes. β-hydroxy butyrate, an NLRP3 inhibitor, also abolished visceral hypersensitivity and colonic hyperpermeability caused by LPS. In contrast, IL-1β induced similar GI alterations to LPS, which were not modified by tranilast. In conclusion, tranilast improved visceral pain and colonic barrier by suppression of the NLRP3 inflammasome in IBS rat models. Tranilast may be useful for IBS treating., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Tolfenamic acid is one of the fenamic acid-derived non-steroid anti-inflammatory drugs (NSAIDs) and has been shown to exhibit anti-cancer activities in several types of cancer. Both mutations and aberrant expression of β-catenin are highly associated with progression of cancer. Therefore, β-catenin is considered to be a promising molecular target for cancer prevention and treatment. The current study investigates the role of tolfenamic acid on β-catenin expression in colon cancer. Treatment with tolfenamic acid led to inhibition of cell growth and down-regulation of β-catenin expression in a dose- and time-dependent manner in human colon cancer cell lines. Reduction of β-catenin upon tolfenamic acid treatment was associated with ubiquitin-mediated proteasomal degradation, without affecting mRNA level and promoter activity of β-catenin. In addition, treatment with tolfenamic acid downregulated Smad2 and Smad3 expression, while overexpression of Smad2, but not Smad3, blocked tolfenamic acid-induced suppression of β-catenin expression. Tolfenamic acid also decreased expression of β-catenin target genes, including vascular endothelial growth factor (VEGF). Compared to adjacent normal tissue, intestinal tumor tissues of Apc(Min/+) mice exhibited increased expression of β-catenin, Smad2, Smad3, and VEGF, which were down-regulated with tolfenamic acid treatment at a dose of 50mg/kg body weight. In conclusion, our findings suggest that tolfenamic acid inhibits growth of colon cancer cells through downregulation of Smad2 and, subsequently, facilitating ubiquitin-proteasome-mediated β-catenin degradation in colon cancer., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Local catabolism of tryptophan (Trp) by indoleamine 2,3-dioxygenase (IDO) is considered an important mechanism of regulating T cell immunity. N-(3,4-dimethoxycinnamonyl) anthranilic acid (3,4-DAA) is an active synthetic anthranilic acid derivative which was proved to be effective to treat type1helper T lymphocyte (Th1) mediated autoimmune diseases such as multiple sclerosis. In this report, we investigated the effects of 3,4-DAA on the acute graft versus host disease (aGVHD) following allogeneic bone marrow transplantation (allo-BMT) and its potential mechanism of action. We established a murine aGVHD model, 3,4-DAA was injected intraperitoneally at 200mg/kg/day per mouse immediately after allo-BMT or at the onset of aGVHD for 14 consecutive days; the signs of aGVHD and the survival were recorded periodically. We revealed that administration of 3,4-DAA after allo-BMT significantly reduced the severity and the histological score of aGVHD; the survival for mice receiving 3,4-DAA prophylaxis and treatment was prolonged in comparison to the vehicle control mice. The plasma levels of IFN-γ, TNF-α, IL-12 and IL-2 in 3,4-DAA treatment group were found to be decreased, while the IDO activity, CD4(+)/CD25(+) Treg cells, and the IL-10, IL-5 and IL-4 levels elevated in these mice. In consistent with the in vivo results, 3,4-DAA also inhibited IFN-γ and IL-2 production of spleen T lymphocytes in vitro. Our findings suggest that 3,4-DAA can diminish the murine experimental aGVHD through regulating T cell proliferation and polarization; this property makes it a potential alternative agent for prevention and treatment of GVHD in the clinic., (© 2013.)

Tranilast (TL) has been clinically used for the treatment of airway inflammatory diseases, although the clinical use of TL is limited because of its poor solubility and systemic side effects. To overcome these drawbacks, a novel respirable powder of TL (CSD/TL-RP) for inhalation therapy was developed using nanocrystal solid dispersion of TL (CSD/TL). Stability study on CSD/TL-RP was carried out with a focus on inhalation performance. Even after 6 months of storage at room temperature, there were no significant morphological changes in micronized particles on the surface of carrier particles as compared with that before storage. Cascade impactor analyses on CSD/TL-RP demonstrated high inhalation performance with emitted dose and fine particle fraction (FPF) of ca. 98% and 60%, respectively. Long-term storage of CSD/TL-RP resulted in only a slight decrease in FPF value (ca. 54%). Inhaled CSD/TL-RP could attenuate antigen-induced inflammatory events in rats, as evidenced by marked reduction of granulocytes in bronchoalveolar lavage fluid and inflammatory biomarkers such as eosinophil peroxidase, myeloperoxidase, and lactate dehydrogenase. These findings were consistent with decreased expression levels of mRNAs for nuclear factor-kappa B and cyclooxygenase-2, typical inflammatory mediators. Given these findings, inhalable TL formulation might be an interesting alternative to oral therapy for the treatment of asthma and other airway inflammatory diseases with sufficient dispersing stability., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Accelerated coronary arteriosclerosis remains a major problem for the long-term survival of cardiac transplant recipients. However, the pathogenesis of graft vasculopathy is poorly understood and there is no effective therapy. Tranilast is a promising drug that may prevent post-angioplasty restenosis. Here, we investigated whether orally administered tranilast inhibits the development of intima hyperplasia in a mouse model of cardiac transplantation. Cardiac allografts from BALB/c mice were transplanted heterotopically into C3H/He mice. Mice were administered either vehicle or tranilast everyday by gavage. Morphometrical analysis of the cardiac allografts harvested at 2 months revealed that the administration of tranilast significantly reduced the development of coronary atherosclerosis. In the mice treated with tranilast, up-regulation of the cyclin-dependent kinase inhibitor p21 was observed in the allografts, accompanied by a reduced number of proliferating cells. Tranilast also suppressed transforming growth factor-beta (TGF-beta) expression. Tranilast may be effective in preventing transplant-associated arteriosclerosis through its anti-inflammatory and anti-proliferative effects.

The effects of Ta-383 (0.016, 0.08, 0.4, 2 and 10 mg/kg) and anti-rheumatic drugs (lobenzarit 10 and 50 mg/kg, dexamethasone 0.25 mg/kg) were evaluated on type II collagen-induced arthritis in DBA/1J mice. The arthritis score was markedly suppressed in the groups treated with dexamethasone and TA-383. Serum anti-type II collagen IgG was significantly suppressed in the groups treated with dexamethasone and 0.4 mg/kg TA-383. Histopathological evaluation of the knee joints revealed suppression of the inflammatory changes in the groups treated with dexamethasone and TA-383. These findings suggest that the histopathological examination of the joints of the animal model is useful for the evaluation of anti-rheumatic drugs, and that TA-383 has suppressive effects on type II collagen-induced arthritis, an animal model for human rheumatoid arthritis.

In this open randomized study, we evaluated the efficacy of Tranilast, one of the anti-inflammatory drugs, on otitis media with effusion in children. Sixty-two patients (103 ears) were divided into two groups: Group A was given Tranilast and local treatment (nasal and tubal); Group B only received local treatment (control for Group A). The overall improvement rating assessed as "moderately improved or above" for Group A was 63.6%, Group B 47.9%. There was a significant improvement in Group A as compared to Group B (p < 0.05). In subjects who suffered from otitis media with effusion for over 2 months. Group A exhibited 50.0% of efficacy while Group B only 15.4% (p < 0.05).

Tranilast is an orally effective anti-allergic agent evaluated for clinical activity in prevention of symptoms of allergic rhinitis. It was investigated in a randomized, pre-seasonal, and in-seasonal treatment of tranilast to test the clinical efficacy and pathophysiological changes on the onset of nasal symptoms in season. Thirty-eight patients with a history of Sugi pollinosis and positive allergic tests were treated with tranilast 300 mg daily 6 to 7 weeks before the onset of the pollen season and continuously during the season or no medication including tranilast until the onset of clinical symptoms in season. The number of sneezing and the grade of stuffiness at the onset of pollen season were inhibited significantly in pre-seasonal treatment. The number of mast cells and eosinophils in season increased compared with off-season and the threshold of nasal hypersensitivity in season decreased compared with off-season in inseasonal treatment, but not in pre-seasonal treatment. This study indicates that tranilast may have the prophylactic effect for Sugi pollinosis.

Prostaglandins (PGs) may be involved in the development of the symptoms of endometriosis. Therefore 18 patients with pelvic endometriosis were treated in placebo controlled double-blind trial with different prostaglandin biosynthesis inhibitors. These drugs were: acetylsalicylic acid (0.5 g x 3) exerting a weak PG-synthetase inhibition, indomethacin (25 mg x 3) inhibiting PG-synthetase, and as a representative of fenamates, tolfenamic acid (200 mg x 3), which both inhibits PG-synthetase and antagonizes PGs at the target level. The therapeutic effect was evaluated using a specific endometriosis score separately during menstruation and in premenstrum. Prostaglandin biosynthesis inhibitors did not alleviate premenstrual complaints better than placebo. During menstruation tolfenamic acid relieved endometriotic symptoms more effectively than placebo while indomethacin and acetylsalicylic acid did not differ from placebo. A drug which inhibit both the synthesis and action of PGs can thus be used in the alleviation of secondary dysmenorrhea due to endometriosis.