tranilast and Hyperplasia

Tranilast has been used in allergic diseases because of its inhibitory effect on mast cells; it also has an anti-fibrotic effect in several diseases. Pentoxifylline (PTX), a methylxanthine derivative, is a potent anti-inflammatory drug that is known to manifest its effect through the inhibition of Th1 cytokine, but with an uncertain effect on Th2 cytokine. Seven-week-old female BALB/c mice were studied as a chronic asthma model. The mice were challenged with house dust mite (HDM) antigen for 7 weeks. Each group of mice was given an intraperitoneal injection of tranilast, PTX, or tranilast plus PTX before antigen administration. In this mouse model of chronic asthma, tranilast, and PTX each had an inhibitory effect on airway remodeling as well as on airway hyperresponsiveness (AHR) and airway inflammation. The improved events of these drugs were related with the inhibition of the Th2 cytokine IL-13 and TGF-beta 1. Immunohistochemical analysis showed that decreases in the peribronchial trichrome stained area in each treatment group were associated with improvements in the peribronchial smooth muscle hyperplasia, collagen type I, and collagen type III deposition. These drugs could have potential beneficial effects on chronic asthma, especially with respect to airway remodeling.

Topics: Animals; Anti-Allergic Agents; Antigens, Dermatophagoides; Asthma; Bronchial Hyperreactivity; Bronchioles; Bronchoalveolar Lavage Fluid; Cell Count; Drug Therapy, Combination; Eosinophils; Female; Fibrillar Collagens; Goblet Cells; Hyperplasia; Immunoglobulin E; Interleukin-13; Leukocytes; Mice; Mice, Inbred BALB C; Muscle, Smooth; ortho-Aminobenzoates; Pentoxifylline; Pulmonary Fibrosis; Specific Pathogen-Free Organisms; Transforming Growth Factor beta1

N-(3'4'-dimethoxycinnamoyl)-anthranilic acid (tranilast) is a drug that has been shown to reduce the incidence of restenosis after angioplasty in middle-scale clinical trials. Despite clinical interest in this drug, the pharmacological actions of tranilast remain relatively unexplored at a molecular level.. We evaluated the effects of tranilast on vascular smooth muscle cell (VSMC) proliferation in wild-type mice and in mice lacking a cyclin-dependent kinase inhibitor, p21(WAF1) (p21). Tranilast potently inhibited the proliferation of VSMC cultures derived from wild-type mice, but VSMCs derived from p21-deficient (p21-/-) mice were unaffected by this treatment. In a mouse femoral artery model of vascular injury, tranilast administration to wild-type mice led to an upregulation of p21 expression and a decrease in the number of proliferating VSMCs, as determined by immunostaining for proliferating cell nuclear antigen. In contrast, tranilast had no effect on the number of proliferating cell nuclear antigen-positive cells in the injured arteries of p21-/- mice. Administration of tranilast significantly reduced the neointimal VSMC hyperplasia in wild-type mice at 4 weeks but had no effect on lesion formation in p21-/- mice.. Our findings provide genetic evidence that tranilast inhibits intimal hyperplasia via a p21-dependent pathway, an activity that may contribute to its efficacy in the prophylactic treatment of postangioplasty restenosis.

Topics: Animals; Arteriosclerosis; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Hyperplasia; Mice; Muscle, Smooth, Vascular; ortho-Aminobenzoates; Phosphorylation; Recurrence; Retinoblastoma Protein; Up-Regulation

We report here that the traditional Chinese formulation, Chaihu-jia-Longgu-Muli-tang (CLM), significantly inhibited the increase in intimal thickening in rat carotid artery injured by balloon endothelial denudation, which mimics many aspects of restenosis after percutaneous coronary intervention (PCI) in humans. CLM, Saiko-ka-Ryukotsu-Borei-to in Japanese, is commonly prescribed for symptoms accompanying hypertension and atherosclerosis in Japanese Kampo medical care. CLM administered orally 1 week before and 1, 4 and 8 weeks after balloon injury inhibited the increase in intimal area, intimal/medial ratio and stenosis ratio. To our knowledge, this is the first report demonstrating inhibitory effects of a traditional Chinese formulation on intimal thickening of carotid artery after balloon injury. It is worth noting that CLM maintained its inhibitory effect up to 8 weeks after balloon injury. The reduction in intimal thickening by CLM could have resulted from inhibition of intimal smooth muscle cell proliferation, which was assessed by immuno-histochemical analysis using monoclonal antibody against proliferating cell nuclear antigen. Therefore, CLM may be a favourable candidate for prevention of restenosis after PCI. Moreover CLM may have a therapeutic value in the prevention of atherosclerosis, because restenosis after PCI is considered to be an accelerated atherosclerosis.

Topics: Angioplasty, Balloon, Coronary; Animals; Body Weight; Carotid Artery Injuries; Carotid Stenosis; Cell Division; Drugs, Chinese Herbal; Eating; Endothelium, Vascular; Humans; Hyperplasia; Immunohistochemistry; Male; Medicine, Chinese Traditional; Medicine, Kampo; Molecular Structure; Muscle, Smooth, Vascular; ortho-Aminobenzoates; Platelet Aggregation Inhibitors; Postoperative Complications; Proliferating Cell Nuclear Antigen; Rats; Rats, Wistar; Tunica Intima

N(3,4-dimethoxycinnamoyl) anthranilic acid (tranilast) prevents the synchronous upregulation of isoforms and receptors of the transforming growth factor (TGF)-beta system after arterial injury and reduces restenosis after human coronary angioplasty. However, the effects of tranilast and the importance of the TGF-beta system in stent restenosis, in which inward remodeling is unimportant but inflammatory cell stimulation of neointima formation is exaggerated, are uncertain. Boston minipigs, treated with tranilast or vehicle, were subjected to endoluminal stenting, and the expression of TGF-beta1 and TGF-beta3, the expression of their signaling receptors ALK-5 and TbetaR-II, leukocyte numbers around the stent struts, and neointima development were assessed over 28 days. Stenting greatly increased early (5-day) mRNA expression of the 2 TGF-beta isoforms and their receptors. Immunohistochemical localization later showed that their concentrations were greatest in regions adjacent to stent struts, where leukocytes and collagen deposition were prevalent. Tranilast suppressed these elevations in TGF-beta mRNAs and reduced their immunoreactive peptides detectable around stent struts. The accumulation of leukocytes and deposition of collagen in these regions was also greatly inhibited by tranilast. These effects were associated with a 48% reduction in maximal neointimal cross-sectional area and 43% reduction in mean neointimal cross-sectional area at 28 days (P<0.05). We conclude that tranilast suppresses neointima development after stenting, effects that can be at least partly attributed to its ability to attenuate the induction of the TGF-beta system and leukocyte accumulation around stent struts.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Coronary Restenosis; Coronary Vessels; Drug Administration Schedule; Hyperplasia; Inflammation; Leukocytosis; Male; ortho-Aminobenzoates; Stents; Swine; Transforming Growth Factor beta; Tunica Intima; Up-Regulation

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.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Division; Coronary Artery Disease; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Heart Transplantation; Hyperplasia; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Muscle, Smooth, Vascular; ortho-Aminobenzoates; Transforming Growth Factor beta

Tranilast, which is an antiallergic drug, has a potent effect on preventing postangioplasty restenosis. To elucidate this mechanism, we studied the effect of tranilast on the proliferation of vascular smooth muscle cells (SMCs) in vitro and in vivo. Tranilast decreased the growth rate of SMCs stimulated by either 10% FBS or platelet-derived growth factor. The IC50 value, evaluated as cell number, was 100 micromol/L. These inhibitory effects were associated with inhibition of the retinoblastoma gene product (pRb) phosphorylation. Because pRb phosphorylation is regulated by cyclin-dependent kinases (CDK), we investigated CDK2 and CDK4 activities and the expression of CDK inhibitor p21(waf1/cip1/sdi1) (p21). When SMCs were stimulated by 10% FBS or platelet-derived growth factor, CDK2 and CDK4 activities reached a maximum near the G1/S transition. Tranilast suppressed their activities by >80% without reduction of CDK2/cyclin E and CDK4/cyclin D1 protein levels. These inhibitory effects were associated with enhanced expression of p21 and elevated complexing of p21 with CDK2/CDK4. Next, rat balloon-injured carotid artery was analyzed for intimal thickening and p21 expression. Tranilast-treated rats had a 70% (P<0.001) smaller neointima/media area ratio at 14 days after balloon injury compared with the controls. Immunohistochemical staining demonstrated that, in tranilast-treated rats, p21 was already present in the neointima at day 7 and strongly expressed throughout the neointima at day 14. In control rats, p21 was not observed in the neointima at day 7 but was sparsely expressed at day 14. These data demonstrate that inhibition of CDK2/CDK4 activities by the increased expression of p21 may be one mechanism by which tranilast inhibits SMC proliferation and prevents postangioplasty restenosis.

Topics: Animals; Aorta, Thoracic; Catheterization; CDC2-CDC28 Kinases; Cell Division; Cells, Cultured; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase 4; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinases; Cyclins; Depression, Chemical; Hyperplasia; Male; Muscle, Smooth, Vascular; ortho-Aminobenzoates; Phosphorylation; Platelet-Derived Growth Factor; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Rats; Rats, Sprague-Dawley; Serum Albumin, Bovine; Tumor Suppressor Protein p53; Tunica Intima

Intimal thickening in the femoral artery of spontaneously hypertensive rats (SHR) was initiated by endothelial damage induced by the photochemical reaction between green light and systemic rose bengal. This model represents a non-mechanical method of producing vessel wall denudation. Neointima formation was assessed by calculating the cross-sectional area of intima, media and lumen, using computer analysis. Tranilast (30, 100 and 300 mg/kg, p.o.), administered 2 days prior to endothelial injury, reduced intimal area by 29, 62 and 87%, respectively, compared to that of vehicle-treated controls. In cultured SHR-derived vascular smooth muscle cells, tranilast produced concentration-dependent inhibition of mitogenesis, whether stimulated by platelet-derived growth factor, basic fibroblast growth factor, insulin-like growth factor or fetal bovine serum. These results suggest that tranilast may be effective in preventing coronary restenosis.

Topics: Animals; Anti-Allergic Agents; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelium; Femoral Artery; Hyperplasia; Male; ortho-Aminobenzoates; Rats; Rats, Inbred SHR

Intimal hyperplasia is a serious problem after percutaneous transluminal coronary angioplasty (PTCA). In this study, we investigated the effects of tranilast on intimal hyperplasia in both in vivo and in vitro experiments. For the in vivo experiments, we used the balloon injury model and the cuff treatment model of rabbits fed regular chow. In the balloon injury model, tranilast decreased intimal area, intima/media ratio, stenosis ratio and vascular DNA content after endothelial injury. Also in the cuff treatment model, tranilast suppressed the intimal hyperplasia. In the in vitro experiments, we assessed the effects of tranilast on platelet-derived growth factor-induced rabbit vascular smooth muscle cell (VSMC) migration and proliferation and on collagen synthesis by VSMCs. Tranilast inhibited VSMC migration, proliferation and collagen synthesis. These results suggest that tranilast has a suppressive effect on intimal hyperplasia after a vascular injury such as PTCA.

Topics: Angioplasty, Balloon, Coronary; Angiotensin Receptor Antagonists; Animals; Antihypertensive Agents; Biphenyl Compounds; Cell Division; Cell Movement; Cells, Cultured; Collagen; Disease Models, Animal; DNA; Endothelium, Vascular; Hyperplasia; Imidazoles; Losartan; Male; Muscle, Smooth, Vascular; ortho-Aminobenzoates; Platelet Aggregation Inhibitors; Platelet-Derived Growth Factor; Postoperative Complications; Rabbits; Tetrazoles; Tunica Intima

Intimal hyperplasia is a serious problem after percutaneous transluminal coronary angioplasty. In this study, we assessed the effect of tranilast on vascular intimal hyperplasia after balloon injury in rabbits fed on a high-cholesterol diet. In this animal model, intimal hyperplasia more severe than that in rabbits fed on a normal diet was observed. In addition, medial thickening and lipid deposits in both media and intima were also noted. These findings indicate that balloon injury caused intimal and medial hyperplasia and that this hyperplasia was accelerated by the high cholesterol load. Tranilast (300 mg/kg) significantly decreased the intimal area, medial area, and stenosis ratio, and increased the luminal/total area ratio, in the cholesterol-fed rabbits. These results suggest that tranilast may be useful for prevention of restenosis after percutaneous transluminal coronary angioplasty of patients, including those with a clinical risk of hypercholesterolemia.

Topics: Animals; Anti-Allergic Agents; Catheterization; Cholesterol, Dietary; Coronary Disease; Hyperplasia; Male; Muscle, Smooth, Vascular; ortho-Aminobenzoates; Rabbits