Antithrombotic therapy for improving maternal or infant health outcomes in women considered at risk of placental dysfunction.

BACKGROUND: Pregnancy complications such as pre-eclampsia and eclampsia, intrauterine growth restriction and placental abruption are thought to have a common origin related to abnormalities in the development and function of the placenta. OBJECTIVES: To compare, using the best available evidence, the benefits and harms of antenatal antithrombotic therapy to improve maternal or infant health outcomes in women considered at risk of placental dysfunction, when compared with other treatments, placebo or no treatment. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (17 July 2012). SELECTION CRITERIA: Randomised controlled trials comparing antenatal antithrombotic therapy (either alone or in combination with other agents) with placebo or no treatment, or any other treatment in the antenatal period to improve maternal or infant health outcomes in women considered at risk of placental dysfunction. DATA COLLECTION AND ANALYSIS: Two review authors evaluated trials under consideration for appropriateness for inclusion and methodological quality without consideration of their results according to the prestated eligibility criteria. We used a fixed-effect meta-analysis for combining study data if the trials were judged to be sufficiently similar. We investigated heterogeneity by calculating I² statistic, and if this indicated a high level of heterogeneity among the trials included, we used a random-effects model. MAIN RESULTS: Our search strategy identified 18 reports of 14 studies for consideration. The original review included five studies (484 women) which met the inclusion criteria, with a further five studies included in the updated review, involving an additional 655 women. The overall quality of the included trials was considered fair to good.Nine studies compared heparin (alone or in combination with dipyridamole or low-dose aspirin) with no treatment; and one compared trapidil (triazolopyrimidine).While this review identified the use of heparin to be associated with a statistically significant reduction in risk of perinatal mortality (six studies; 653 women; risk ratio (RR) 0.40; 95% confidence intervals (CI) 0.20 to 0.78), preterm birth before 34 (three studies; 494 women; RR 0.46; 95% CI 0.29 to 0.73) and 37 (five studies; 621 women; RR 0.72; 95% CI 0.58 to 0.90) weeks' gestation, and infant birthweight below the 10th centile for gestational age (seven studies; 710 infants; RR 0.41; 95% CI 0.27 to 0.61), there is a lack of reliable information available related to clinically relevant, serious adverse infant health outcomes, which have not been reported to date. AUTHORS' CONCLUSIONS: While treatment with heparin for women considered to be at particularly high risk of adverse pregnancy complications secondary to placental insufficiency was associated with a statistically significant reduction in risk of perinatal mortality, preterm birth before 34 and 37 weeks' gestation, and infant birthweight below the 10th centile for gestational age when compared with no treatment for women considered at increased risk of placental dysfunction, to date, important information about serious adverse infant and long-term childhood outcomes is unavailable.

Antithrombotic therapy for improving maternal or infant health outcomes in women considered at risk of placental dysfunction.

BACKGROUND: Pregnancy complications such as pre-eclampsia and eclampsia, intrauterine growth restriction and placental abruption are thought to have a common origin related to abnormalities in the development and function of the placenta. OBJECTIVES: To compare, using the best available evidence, the benefits and harms of antenatal antithrombotic therapy to improve maternal or infant health outcomes in women considered at risk of placental dysfunction, when compared with other treatments, placebo or no treatment. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2010). SELECTION CRITERIA: Randomised controlled trials comparing antenatal antithrombotic therapy (either alone or in combination with other agents) with placebo or no treatment, or any other treatment in the antenatal period to improve maternal or infant health outcomes in women considered at risk of placental dysfunction. DATA COLLECTION AND ANALYSIS: Two review authors evaluated trials under consideration for appropriateness for inclusion and methodological quality without consideration of their results according to the prestated eligibility criteria. We used a fixed-effect meta-analysis for combining study data if the trials were judged to be sufficiently similar. We investigated heterogeneity by calculating I(2) statistic, and if this indicated a high level of heterogeneity among the trials included we used a random-effects model. MAIN RESULTS: Our search strategy identified 14 reports of 10 studies for consideration, of which five met the inclusion criteria, involving 484 women. Four studies compared heparin (alone or in combination with dipyridamole) with no treatment; and one compared trapidil (triazolopyrimidine). While there were no statistically significant differences identified for the primary outcomes following heparin treatment, it was associated with a reduction in the risk of pre-eclampsia, eclampsia, and infant birthweight less than the 10th centile for gestational age. AUTHORS' CONCLUSIONS: The review identified no significant differences for the primary outcomes perinatal mortality, preterm birth less than 34 weeks' gestation, and childhood neurodevelopmental handicap, although the number of studies and participants was small. While treatment with heparin appears promising with a reduction in pre-eclampsia, eclampsia, and infant birthweight less than the 10th centile for gestational age, the number of studies and participants included was small, and to date important information about serious adverse infant and long-term childhood outcomes is unavailable. Further research is required.

Protective effect of trapidil and l-arginine against renal and hepatic toxicity induced by cyclosporine in rats.

RATIONALE: Cyclosporine A (CsA) leads to renal and liver injury, production of free radicals and nitric oxide (NO) deficiency. This study investigates the possible protective effects of trapidil and L-arginine against CsA-induced tissue injury. OBJECTIVES: Forty adult male Wistar rats (180 +/- 20 g) were divided into five groups, eight animals in each. The first group served as control, second group served as CsA group, third group served as CsA + trapidil group, fourth group served as CsA + L-arginine group, and fifth group served as CsA + trapidil + L-arginine group. Kidney and liver functions, inflammatory mediators, cytokines, oxidant and antioxidant parameters as well as histopathological studies of renal and liver tissue were assessed in all groups. MAIN FINDINGS: CsA induced renal and hepatic dysfunction, which was confirmed by laboratory and histopathological examination. Administration of trapidil diminished the renal and liver injury and significantly attenuated the levels of serum creatinine, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), interleukin-1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1), and oxidative stress, while it significantly elevated the level of serum nitric oxide and the activity of antioxidative stress. L-Arginine gave the same trend as trapidil, but trapidil effect was more pronounced. Coadministration of trapidil + L-arginine significantly ameliorated the toxic effect of CsA, but did not differ significantly from the effect of trapidil alone. CONCLUSIONS: Treatment with trapidil or L-arginine diminished the renal and hepatic CsA-induced toxicity. However, the effect of trapidil was more pronounced. Therefore, treatment with trapidil alone may be the most economic and effective as a potential therapeutic agent in CsA injury.

[Investigation of the effects of low dose aspirin therapy on primary and secondary prevention of cardiovascular disease].

We examined the efficacy of low-dose aspirin for the primary prevention of atherosclerotic events in patients with type 2 diabetes. Multicenter, prospective, randomized, open -label, blinded end-point trial enrolled 2,539 patients with type 2 diabetes. A total of 154 atherosclerotic events occurred: 68 in the aspirin group and 86 in the nonaspirin group (log -rank test, p = 0.16). The multicenter study was performed to find out whether aspirin or trapidil would improve clinical outcome. The study was a multicenter, open-label, randomized controlled trial of aspirin 81 mg/day, trapidil 300 mg/day, and no antiplatelets in patients with acute myocardial infarction (AMI) admitted within 1 month from the onset of symptoms. Long-term use of aspirin reduced the incidence of recurrent AMI (p = 0.0045).

Protective effect of trapidil on long-term histologic damage in a rat model of testicular ischemia-reperfusion injury.

OBJECTIVES: Trapidil is an antianginal compound with a broad spectrum of pharmacological activities. In recent years, it has been used successfully to decrease ischemia-reperfusion injury in several organ systems. We evaluated the effect of trapidil on the long-term histologic damage in testicular ischemia-reperfusion injury. METHODS: Adult male Wistar rats were divided into three groups of six rats each. One group underwent 2 h of testicular torsion; one received pretreatment with trapidil before detorsion; and one group underwent sham operation. All rats underwent bilateral orchiectomy 60 days after the experiment. The mean seminiferous tubular diameter, germinal epithelial cell thickness, and mean testicular biopsy score were determined by histological examination of each testis. RESULTS: Testicular torsion-detorsion caused a significant decrease in the mean seminiferous tubular diameter, germinal epithelial cell thickness, and mean testicular biopsy score in the ipsilateral testes, but not in the contralateral testes. The animals treated with trapidil had a significant increase in these histological parameters as compared to the torsion-detorsion group. CONCLUSION: Trapidil administration before reperfusion may have the potential to decrease the long-term histologic damage that occurs after experimental testicular torsion. Trapidil is used as an antianginal drug and additional clinical studies are required to elucidate the protective role of trapidil in patients with testicular torsion.

The role of trapidil on neuronal apoptosis in neonatal rat model of hypoxic ischemic brain injury.

BACKGROUND: Hypoxic ischemic brain injury (HIBI) is a common cause of neonatal mortality and morbidity. Trapidil is an antiplatelet agent and several studies demonstrate the beneficial effect of trapidil in various forms of tissue injury. The effects of trapidil on neuronal apoptosis in HIBI have not been reported previously. AIMS: The aim of this study is to evaluate the effect of trapidil on neuronal apoptosis in neonatal rat model of HIBI. STUDY DESIGN: Seven-day-old Wistar rat pups were subjected to right common carotid artery ligation and hypoxia (92% nitrogen and 8% oxygen) for 2h. They were treated with trapidil or saline either immediately before or after hypoxia. In sham group animals, neither ligation, nor hypoxia were performed. Neuronal apoptosis was evaluated by the terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL) and caspase-3 staining methods. RESULTS: Trapidil treatment either before or after hypoxia results in significant reduction of the numbers of apoptotic cells in both hemispheres, when it is compared with saline treatment group. The numbers of apoptotic cells in right hemispheres in all groups are significantly higher than that in the left hemispheres. CONCLUSIONS: These results show that trapidil administration either before or after hypoxia reduces neuronal apoptosis and we propose that trapidil may be a novel approach for the therapy of HIBI.

Pharmacologic approaches to restenosis prevention.

Despite significant advances in technology and technique, coronary restenosis remains the primary limitation of percutaneous transluminal coronary angioplasty (PTCA). Among patients undergoing PTCA, between 20% and 50% of patients who do not receive a stent and 10%-30% of those who do receive a stent develop restenosis within 6 months of the procedure. Drug-eluting stents, which release high local concentrations of antiproliferative or immunosuppressive agents directly into the vessel wall at the site of the lesion, have dramatically reduced the incidence of restenosis in patients undergoing PTCA. However, even with drug-eluting stents, a significant percentage of higher-risk patients develop in-stent restenosis. These data suggest that a role remains for effective, well-tolerated systemic pharmacologic therapies to further reduce the rate of restenosis. To date, the majority of systemic agents tested for restenosis prevention have failed to show significant benefit. Only 2 agents, probucol and cilostazol, have consistently demonstrated efficacy in preventing restenosis. In addition, the investigational agent AGI-1067 has demonstrated promising efficacy in early clinical trials. Together with drug-eluting stents, these therapies may for the first time reduce the rate of restenosis to near zero, even in high-risk patients, such as individuals with diabetes mellitus.

Protective effect of trapidil against oxidative organ damage in burn injury.

Animal models of thermal injury indicate reactive oxygen species and inflammatory cytokines as causative agents in tissue injury on various organs distant from the original wound. Trapidil has various properties, such as inhibition of platelet aggregation and lipid peroxidation as well as reduction of the inflammatory response to injury. This study was designed to determine the possible protective effect of trapidil treatment against oxidative organ damage in lung, intestine and kidney induced by cutaneous thermal injury. Thirty Wistar rats were randomly divided into five groups. Sham group (n=6) was exposed to 21 degrees C water while burn-3 h group (n=6) and burn+trap-3h group (n=6), burn-24 h (n=6) and burn+trap-24 h groups were exposed to boiling water for 12s to produce a full thickness burn in 35-40% of total body surface area. In both burn+trap-3 h and burn-trap-24 h group, 8 mg/kg trapidil was given intravenously immediately after thermal injury. Three and 24 h later, tissue samples were taken for biochemical analysis from lung, intestine and kidney and blood samples were obtained to determinate serum TNF-alpha levels. Cutaneous thermal injury caused a significant increase in myeloperoxidase (MPO) activity and malondialdehyde (MDA) and 3-nitrotyrozine (3-NT) levels in all tissues and elevated serum TNF-alpha levels at post-burn 3 and 24 h. Trapidil treatment significantly reduced in biochemical parameters, as well as serum TNF-alpha levels. These data suggest that trapidil has a protective effect against oxidative organ damage in burn injury.

Trapidil protects ischemic hearts from reperfusion injury by stimulating PKAII activity.

OBJECTIVE: The cardioprotective effects of trapidil on ischemic reperfused (I/R) rabbit hearts were studied. Recently, we had shown that trapidil might activate protein kinase A (PKA). In this study, we examined the exact mode of PKA stimulating activity of trapidil. Finally, we investigated the effect of trapidil on the phosphorylation state of phospholamban (PLB), a major PKA target in the heart and key regulator of Ca(2+) sequestration via the sarcoplasmic reticulum Ca(2+)-ATPase. METHODS: Langendorff-hearts of New Zealand White rabbits were perfused at constant volume and subjected to global low-flow ischemia for 2 h, followed by 1 h of reperfusion. Subsequently, hearts were used for Western blot analysis of PLB phosphorylation. Furthermore, three different regulatory subunits and one catalytic subunit of PKA were overexpressed in E. coli. These PKA subunits were purified and used in an in vitro assay system to test the impact of trapidil on PKA activities in the absence and presence of cAMP. RESULTS: I/R resulted in a significant increase in left ventricular end-diastolic pressure and creatine kinase efflux in the hearts. Trapidil (10 microM) prevented these alterations. Using recombinant cAMP-free PKA isoforms, it was found that trapidil specifically stimulated PKAII but only did so in the presence of small amounts of added cAMP. Furthermore, the PKA-dependent 16Ser phosphorylation of PLB was markedly reduced in I/R. Trapidil largely normalized the 16Ser phosphorylation of PLB. CONCLUSIONS: The data demonstrate cardioprotective actions of trapidil in I/R and show a PKAII-dependent cAMP sensitizing effect of the compound. They also indicate PKA-dependent PLB phosphorylation as a target, suggesting an improved Ca(2+) uptake by the sarcoplasmic reticulum. This action might be involved in the cardioprotective effects of trapidil.

Triazolopyrimidine (trapidil), a platelet-derived growth factor antagonist, inhibits parathyroid bone disease in an animal model for chronic hyperparathyroidism.

Parathyroid bone disease in humans is caused by chronic hyperparathyroidism (HPT). Continuous infusion of PTH into rats results in histological changes similar to parathyroid bone disease, including increased bone formation, focal bone resorption, and severe peritrabecular fibrosis, whereas pulsatile PTH increases bone formation without skeletal abnormalities. Using a cDNA microarray with over 5000 genes, we identified an association between increased platelet-derived growth factor-A (PDGF-A) signaling and PTH-induced bone disease in rats. Verification of PDGF-A overexpression was accomplished with a ribonuclease protection assay. Using immunohistochemistry, PDGF-A peptide was localized to mast cells in PTH-treated rats. We also report a novel strategy for prevention of parathyroid bone disease using triazolopyrimidine (trapidil). Trapidil, an inhibitor of PDGF signaling, did not have any effect on indexes of bone turnover in normal rats. However, dramatic reductions in marrow fibrosis and bone resorption, but not bone formation, were observed in PTH-treated rats given trapidil. Also, trapidil antagonized the PTH-induced increases in mRNA levels for PDGF-A. These results suggest that PDGF signaling is important for the detrimental skeletal effects of HPT, and drugs that target the cytokine or its receptor might be useful in reducing or preventing parathyroid bone disease.

Fast and reproducible vascular neointima formation in the hamster carotid artery: effects of trapidil and captopril.

Neointima formation was induced in the hamster carotid artery by mechanical intraluminal injury with a catheter covered with roughened dental cement, Neointimal thickening occurred as early as 7 days after denudation and further increased during the next 1 to 2 weeks. Proliferation indices of smooth muscle cells (SMCs) showed the highest proportion of proliferating cells in the media and neointima respectively 1 and 5 days after the vascular injury. Transmission and scanning electron microscopy of damaged carotid artery sections as well as immuno-histochemical stainings of von Willebrand factor (vWF) confirmed that reendothelialization was progressive and already complete on day 14, at which time the neointima formation was almost complete. In order to pharmacologically characterize this model further, the effects on neointima formation of trapidil (triazolopyrimidine), a platelet-derived growth factor (PDGF) antagonist, and captopril, an angiotensin converting enzyme inhibitor, were investigated. Trapidil administered orally twice daily at total doses of 25, 50 and 100 mg/kg/day, started 3 days prior to infliction of injury and up to 7 or 14 days after the catheterization, significantly reduced neointima formation. Captopril administered orally three times daily at a total dose of 100 mg/kg/day, equally reduced neointima formation, with 100 mg/kg/day trapidil being more effective than 100 mg/kg/day captopril 7 days after injury. When the treatment by either one of these drugs was arrested on day 7, neointima formation resumed quickly. The hamster appears to be a small, reproducible and fast model for the study of SMC proliferation, requiring only relatively small amounts of experimental drugs. The model furthermore is sensitive to substances known to reduce neointima formation in other animal models.

Effects of aspirin and trapidil on cardiovascular events after acute myocardial infarction. Japanese Antiplatelets Myocardial Infarction Study (JAMIS) Investigators.

Aspirin therapy confers conclusive net benefits in the acute phase of evolving myocardial infarction, but no clear evidence of benefit from the long-term use of aspirin after acute myocardial infarction (AMI) has been shown in any single study. This multicenter study, the Japanese Antiplatelets Myocardial Infarction Study, was performed to find out whether aspirin or trapidil would improve clinical outcome compared with no antiplatelets in postinfarction patients. The study was a multicenter, open-label, randomized controlled trial of aspirin 81 mg/day, trapidil 300 mg/day, and no antiplatelets in patients with AMI admitted within 1 month from the onset of symptoms. Seven hundred twenty-three patients were enrolled at 70 hospitals in 18 prefectures of Japan; 250 were randomly assigned to treatment with 81 mg aspirin (aspirin group), 243 to that with trapidil (trapidil group), and 230 were not given antiplatelet agents. The mean follow-up period was 475 days. This study demonstrated that long-term use of aspirin at the dose of 81 mg/day reduced the incidence of recurrent AMI compared with the group receiving no antiplatelets after AMI (p = 0.0045) and that trapidil also reduced the occurrence of reinfarction compared with the group receiving no antiplatelets, but the difference was not significant (p = 0.0810). The incidence of cardiovascular events including cardiovascular death, reinfarction, uncontrolled unstable angina requiring admission to hospital, and nonfatal ischemic stroke was reduced in the group receiving 300 mg trapidil daily compared with the group receiving no antiplatelets (p = 0.0039). The use of aspirin 81 mg/day provided almost no benefit over no antiplatelets therapy in the incidence of cardiovascular events. In conclusion, low-dose aspirin (81 mg) effectively prevented recurrent AMI in postinfarction patients after thrombolysis or coronary angioplasty when used over a long term. Furthermore, the long-term use of trapidil resulted in a significant reduction in the incidence of cardiovascular events.

Effect of trapidil on cardiovascular events in patients with coronary artery disease (results from the Japan Multicenter Investigation for Cardiovascular Diseases-Mochida [JMIC-M]).

A large-scale study was conducted to assess the effect of long-term administration of trapidil on the prognosis of patients with angiographic evidence of coronary artery disease (CAD). A large-scale, multicenter study, the Japan Multicenter Investigation for Cardiovascular Diseases-Mochida was an open-label, randomized trial of 1,743 patients with CAD who were < or =70 years old and had angiographic evidence of >25% stenosis in any coronary artery. We randomly assigned the patients to receive medical treatment either with trapidil 100 mg 3 times daily (trapidil group, n = 873) or without trapidil (control group, n = 870). The mean follow-up period was 924 days. The incidence of cardiovascular events, including cardiac death, nonfatal myocardial infarction, angina pectoris/heart failure requiring hospitalization, and cerebrovascular events was 11.1% in the trapidil group and 14.9% in the control group (relative risk 0.75, 95% confidence interval 0.58 to 0.98, p = 0.036). Thus, long-term intervention with trapidil in CAD reduces the incidence of cardiovascular events and improves the prognosis of patients with CAD.

Pharmacological management of an impending placental insufficiency.

By means of drug administration a further decrease of the placental circulation in premature sonographic maturity of the placenta could be prevented via influencing the TXA2/PGI2 balance. Treatment of premature sonographic placental maturity with 50 mg acetylsalicylic acid (ASA) per day and three times daily 100 mg Rocornal, respectively, resulted in a significant increase of the birth weights. In a second series of experiments, three groups were treated with 50 mg/day ASA or 250 mg ASA/once per week and three times/day 100 mg Rocornal, respectively, from the 18th or 20th week of gestation to the 35th week. Subsequently, they were compared to a group of untreated controls. The birth weights of all treated groups were statistically significantly higher. The underlying mechanism is suggested to be an improved microcirculation.

Prevention of cerebral ischemic symptoms in cerebral vasospasm with trapidil, an antagonist and selective synthesis inhibitor of thromboxane A2.

The results of our previous experimental and clinical studies led us to the hypothesis that, in the pathogenesis of cerebral vasospasm, subarachnoid focal acidosis resulting from anaerobic changes of subarachnoid clots may be a factor upsetting the balanced synthesis of both thromboxane A2 and prostaglandin I2 from prostaglandin endoperoxides on the inner surface of cerebral arteries. Thus, there is a higher concentration of thromboxane A2, a prostanoid that causes arterial contraction and platelet aggregation. We tested the administration of trapidil, an antagonist and selective synthesis inhibitor of thromboxane A2, in a series of 20 cases for the prevention of cerebral vasospasm and cerebral ischemia after aneurysmal rupture. Vasospasm was demonstrated by angiography in 9 of these cases, but only 2 of the 9 showed mild signs of cerebral ischemia. Of the 20 patients, 15 were discharged from the hospital as cured and 3 had a neurological deficit at discharge. Our findings suggest the significance in symptomatic vasospasm of thrombus formation by platelet aggregation and the effectiveness of trapidil as a preventive.

Inhibitory effect of trapidil on human meningioma cell proliferation via interruption of autocrine growth stimulation.

In a previous study, the authors demonstrated that meningioma cells secrete platelet-derived growth factor (PDGF)-like molecules that stimulate their own growth in an autocrine manner. Based on that finding, a study was undertaken to examine the effect of trapidil, a drug known to have an antagonistic action against PDGF, on cell proliferation of human meningiomas in culture. Trapidil showed a dose-dependent inhibition of meningioma cell proliferation in the absence of any exogenous mitogenic stimulation. The maximum effect was observed at a concentration of 100 micrograms/ml, with the decrease in cell growth ranging from 16% to 54% compared to control samples. Trapidil similarly inhibited the basal deoxyribonucleic acid (DNA) synthesis assessed by [3H]-thymidine incorporation in three of seven meningiomas. While the conditioned medium generated from meningioma cells remarkably stimulated the proliferation of meningioma cells (166% to 277% of control), this effect was strikingly inhibited by the addition of trapidil. Trapidil also inhibited conditioned medium-stimulated DNA synthesis, even when there was no effect on basal DNA synthesis. Furthermore, trapidil significantly inhibited the epidermal growth factor (EGF)-stimulated proliferation of meningioma cells. This inhibitory effect on EGF-stimulated cell proliferation was also observed in nontumorous fibroblasts, demonstrating that trapidil is not an antagonist specific to PDGF. The addition of trapidil (30 micrograms/ml) in combination with bromocriptine (1 microM) showed an additive inhibitory effect on the meningioma cell growth compared to trapidil or bromocriptine alone. The overall results suggest that trapidil exhibits an inhibitory effect on meningioma cell proliferation through blocking the mitogenic stimulation induced by autocrine or exogenous growth factors, and may be considered as a possible new approach to the medical treatment of meningiomas.

Evidence for "response to injury" hypothesis.

Role of platelet-derived growth factor (PDGF) in myointimal thickening described in "response to injury" hypothesis was investigated with artery of rats in culture and with air-injured artery of rats. PDGF promoted cell growth in ring preparation of carotid artery in culture denuded with citrate. It did not promote any cell growth in preparations without denudation. Trapidil, a PDGF antagonist, inhibited the cell growth promoted by PDGF in the denuded arterial ring. Systemic injection of PDGF was performed for 8 days to rats with thrombocytopenia induced by injections of anti-platelet serum. This treatment caused myointimal thickening of carotid artery 10 days after denudation by means of air injury. Trapidil at oral intake levels of 1, 3 and 30 mg/kg/day inhibited this change observed in denuded site of artery. Trapidil at oral intake of 6 mg/kg/day also inhibited myointimal thickening observed 15 days after denudation of carotid artery by air injury in normotensive and spontaneous hypertensive rats both with normal platelet counts. These results evidenced the role of PDGF in myointimal thickening described in "response to injury" hypothesis and clinical use of trapidil may be a new approach to the treatment of atherosclerosis.

Double-blind randomized multicenter study on the efficacy of trapidil versus isosorbide dinitrate in stable angina pectoris.

BACKGROUND: Trapidil is an inhibitor of phosphodiesterase I-IV with resulting positive lusitropic, vasodilating, and antiplatelet effects. HYPOTHESIS: This study was undertaken to compare the antianginal efficacy of trapidil with that of isosorbide dinitrate (ISDN) in patients with stable angina pectoris. METHODS: We studied 95 patients with stable angina pectoris who were randomized into a double-blind parallel group study with either oral trapidil or ISDN. After a 1-week run-in period and a 2-week wash-out phase, the patients received either trapidil 200 mg t.i.d. (n = 48) or ISDN 20 mg t.i.d. (n = 47) for 12 weeks. All antianginal medication, except sublingual glyceryl trinitrate (GTN), was discontinued during the study. Patients underwent an exercise electrocardiogram on an ergometer bicycle according to a modified Bruce protocol before and at 6 and 12 weeks during treatment. RESULTS: The workload capacity increased from 583 +/- 281 W.min before treatment to 833 +/- 444 W.min after 12 weeks of treatment in the trapidil group (p < 0.01) and from 555 +/- 276 W.min to 827 +/- 361 W.min in the ISDN group (p < 0.01). The anginal attacks per week as well as the use of GTN decreased significantly in both groups. After 12 weeks of therapy, the cumulative ST-segment depression during exercise decreased by 67% in the trapidil patients and by 23% in the ISDN patients. Compared with baseline, the double product at the 75 W level was reduced in both groups after 12 weeks of treatment. Blood pressure and heart rate at rest remained nearly unchanged. Overall, no statistical difference was found between the two study groups. The tolerability was good. CONCLUSION: Oral trapidil therapy is safe and effective in stable angina pectoris and is equivalent to standard therapy with ISDN.

Restenosis following coronary angioplasty.

Restenosis is the most important problem limiting the success of coronary angioplasty. Clinically, restenosis is seen in approximately one-third of patients undergoing percutaneous transluminal coronary angioplasty. Several clinical and angiographic risk factors have been identified which may contribute to the development of restenosis. Histopathologic studies indicate that restenosis is characterized by intimal proliferation of smooth muscle cells in a loose connective tissue matrix. These intimal lesions are associated predominantly with the nonatheromatous portion of the vessel wall. Thinning of the media of the plaque-free wall and marked fragmentation of the internal elastic lamina are also seen. Traumatic injury of the vessel wall during angioplasty probably triggers a series of cellular and subcellular events which may ultimately lead to myointimal proliferation and restenosis. Although the exact mechanism by which this occurs is unknown, several factors may enhance smooth muscle cell growth and therefore may play a role in the development of restenosis. These include platelet deposition, mechanical stretching of the media, inflammation of the vessel wall, the activity of growth factors, and alterations in vessel geometry. These possible mechanisms of restenosis suggest several potential ways to limit the proliferative response to vascular injury. Anticoagulants and platelet antagonists, direct inhibitors of smooth muscle proliferation, anti-inflammatory agents, growth factor inhibitors, and new devices which improve final vessel geometry are currently being tested as methods to curb restenosis. Unfortunately, no treatment has yet been shown to reduce significantly the rate of restenosis following angioplasty. The problem of restenosis will most likely be solved by better understanding of the basic molecular and biologic phenomena involved in vascular injury and repair.

Platelet and endothelial response with trapidil in patients with peripheral obliterative arteriopathy.

The activity of trapidil, an antiaggregating agent with PDGF antagonist properties, was investigated in order to verify its possible modulating effect in the endothelial and platelet activation. PDGF, t-PA, PAI-1 and ET-1 plasma levels were measured before and after a 2 month treatment period with trapidil 200 mg tablets bid or placebo in 30 patients affected by POA in Fontaine stage II. PDGF and PAI-1 significantly (p < 0.05) increased in the placebo group, and PDGF also in the comparison between treatments (p < 0.05). Aggregation data demonstrate an absence of Ca++ antagonist action of trapidil. The results of this study suggest that trapidil can interfere with the combined vascular and platelet response in atherogenesis.