Topical Skin Application of Small-Molecule Antiplatelet Agent against Pressure Injury in Rat Models.

Due to prolonged forced positioning, the incidence of intraoperative pressure injuries is high. This study aimed to explore the impact of small-molecule antiplatelet drugs on pressure injuries by locally applying them before an injury occurs. In the first part of this study, water-soluble tracers with different molecular weights were applied to normal and early-stage pressure-injured skin. Through digital cameras, spectrophotometers, and histological observations, the penetration of tracers into the epidermis was clarified. In the second part of this study, a water-soluble antiplatelet drug called Trapidil (molecular weight = 205 Da) was applied to the left side of the back of a rat before, during, and after compression, and the contralateral side served as a non-intervention control group. The differences in pressure injuries between the two groups were observed through a digital camera, an ultraviolet camera, and temperature measurement, and skin circulation and perfusion were assessed via an intravenous injection of Evans Blue. The first part of this study found that water-soluble tracers did not easily penetrate normal skin but could more easily penetrate pressure-damaged skin. The smaller the molecular weight of the tracer, the easier it penetrated the skin. Therefore, in the next step of research, water-soluble drugs with smaller molecular weights should be selected. The second part of this study found that, compared with the control group, the occurrence rates and areas of ulcers were lower, the gray value was higher, and the skin temperature was lower in the Trapidil group (p < 0.05). After the intravenous Evans Blue injection, skin circulation and perfusion in the Trapidil group were found to be better. In conclusion, this study found that the topical skin application of a small-molecule antiplatelet agent may have significant effects against pressure injuries by improving post-decompression ischemia, providing new insights into the prevention and treatment of intraoperative pressure injuries.

Endothelin-1 induces lysyl oxidase expression in pulmonary artery smooth muscle cells.

The increase in thickening of the arterial wall of pulmonary arterial hypertension (PAH) includes cellular proliferation as well as matrix deposition and interrupted internal elastic lamina (IEL) consisting of a thick homogeneous sheet of elastin. Little is, although, known about the detail of IEL formation in PAH. Endothelin-1 is overexpressed in pulmonary arterioles of PAH. We aimed to examine the expression of genes contributing to IEL formation in pulmonary artery smooth muscle cells (PASMCs) especially focused on lysyl oxidase (LOx), an exreacellular matrix enzyme that catalyzes the cross-linking of collagens or elastin. We quantified mRNA expressions of genes contributing to IEL formation including LOx in PASMCs using real-time quantitative polymerase chain reaction. We stimulated human PASMCs with endothelin-1 with prostacyclin or trapidil. Endothelin-1 significantly increased LOx expression. Prostacyclin and trapidil restored endothelin-1-induced LOx expression to the basal level. Endothelin-1 increased LOx expression strongly in PASMCs from PAH patients compared to those from controls. Trapidil reduced LOx expression only in PASMCs from PAH patients. Overexpressed endothelin-1 in PAH patients can increase expression of LOx and agitate cross-linking of elastin and collagen, resulting in ectopic deposition of these in the vascular media.

Trapidil determines the fate of RHF rats through inhibition of ER stress.

Pulmonary arterial hypertension is a fatal disease, especially when it causes right heart failure (RHF). However, it is difficult to treat. It has been reported that trapidil (Tra) can improve the redox balance and cardiac conditions. In this study, we investigated the effect of Tra on RHF induced by monocrotaline (MCT) in rats. Male Wistar rats were treated with MCT or Tra. Treatment lasted 28 days, then rats were euthanized after echocardiography and catheterization. Subsequently, lungs and right ventricular myocardia were evaluated by hematoxylin and eosin, Masson, and TUNEL staining. Protein expression was detected by western blotting. We found remarkably expanded right ventricle end-diastolic volume, decreased partial pressure of oxygen (PaO2), increased partial pressure of carbon dioxide (PaCO2), right ventricular systolic pressure, mean pulmonary arterial pressure, lung/body weight, and liver/body weight in the RHF rat group, as well as increases in the apoptosis rate and the expression of endoplasmic reticulum stress (ERS)-related proteins. However, these changes were significantly inhibited by Tra. Our data suggested that inhibition of ERS is essential for improving RHF, and that therapeutic intervention of Tra in RHF rats works by reducing ERS.

Trapidil induces osteogenesis by upregulating the signaling of bone morphogenetic proteins.

Platelet-derived growth factor receptor (PDGFR) signaling has been shown to inhibit osteogenesis. However, therapeutic efficacy of inhibiting PDGF signaling to bone regeneration in vivo and the specific mechanisms by which PDGFR signaling inhibits osteogenic differentiation remain unclear. In the present study, we examined the osteogenic effect of inhibiting PDGFR using trapidil, a PDGFR antagonist, in vivo and in vitro, and evaluated its mechanisms. A rat calvarial defect model was analyzed by micro-computed tomography and histology to determine the pro-osteogenic effect of trapidil in vivo. In addition, primary mouse calvarial osteoblast precursors were cultured in osteogenic differentiation medium with trapidil to study the mechanisms. Trapidil greatly promoted bone regeneration in a rat calvarial defect model and osteogenic differentiation of calvarial osteoblast precursors. For the mechanisms, trapidil induced phosphorylation of Smad1/5/9 and mitogen-activated protein kinase (MAPK) leading to enhance expression of Runx2, crucial transcription factor for osteogenesis. The pro-osteogenic effects of trapidil were inhibited by LDN193189, specific inhibitor of bone morphogenetic protein (BMP) receptor, ALK2 and ALK3, and by depletion of ALK3, and treatment with noggin, an antagonist of BMPs. Moreover, trapidil showed a synergistic effect with BMP2 on osteogenic differentiation. In conclusion, trapidil induced BMPR activity through upregulation of BMP signaling, leading to promoted osteogenesis in vitro and in vivo. Attenuated BMPR activity may be involved in the inhibition of osteogenesis by PDGFR signaling.

Trapidil improves hemodynamic, echocardiographic and redox state parameters of right ventricle in monocrotaline-induced pulmonary arterial hypertension model.

BACKGROUND: Pulmonary arterial hypertension is a disease characterized by increased pulmonary vascular resistance and redox imbalance, leading to failure of right ventricle. Trapidil has been described to improve the redox balance and cardiac conditions. HYPOTHESIS: Trapidil can improve the redox balance and contribute to functional improvements of the RV in PAH. METHODS AND RESULTS: Male, 5week-old Wistar rats were divided into four groups: Control, Control + Trapidil, Monocrotaline and Monocrotaline + Trapidil. PAH was induced by an intraperitoneal injection of monocrotaline 60 mg/kg at day 0. Treatment started at day 7 (5 or 8 mg/kg/day) until day 14, when animals were euthanized after echocardiography and catheterism. Right ventricular systolic pressure and pressure/time derivatives were increased in monocrotaline animals. The increased right ventricular diameters in monocrotaline groups were reduced with trapidil. Monocrotaline groups showed higher lipid peroxidation and glutathione peroxidase activity. Trapidil reduced NADPH oxidases activities and increased the reduced glutathiones/total glutathiones ratio. Protein expression of phospholamban in RV was diminished in monocrotaline groups, whereas expression of RyR and SERCA was enhanced in the groups treated with trapidil. CONCLUSION: Our data suggest that trapidil induces an improvement in RV remodeling in PAH model, mitigating the progression of the disease.

Renal Interstitial Platelet-Derived Growth Factor Receptor-ß Cells Support Proximal Tubular Regeneration.

BACKGROUND: The kidney is considered to be a structurally stable organ with limited baseline cellular turnover. Nevertheless, single cells must be constantly replaced to conserve the functional integrity of the organ. PDGF chain B (PDGF-BB) signaling through fibroblast PDGF receptor-ß (PDGFRß) contributes to interstitial-epithelial cell communication and facilitates regenerative functions in several organs. However, the potential role of interstitial cells in renal tubular regeneration has not been examined. METHODS: In mice with fluorescent protein expression in renal tubular cells and PDGFRß-positive interstitial cells, we ablated single tubular cells by high laser exposure. We then used serial intravital multiphoton microscopy with subsequent three-dimensional reconstruction and ex vivo histology to evaluate the cellular and molecular processes involved in tubular regeneration. RESULTS: Single-tubular cell ablation caused the migration and division of dedifferentiated tubular epithelial cells that preceded tubular regeneration. Moreover, tubular cell ablation caused immediate calcium responses in adjacent PDGFRß-positive interstitial cells and the rapid migration thereof toward the injury. These PDGFRß-positive cells enclosed the injured epithelium before the onset of tubular cell dedifferentiation, and the later withdrawal of these PDGFRß-positive cells correlated with signs of tubular cell redifferentiation. Intraperitoneal administration of trapidil to block PDGFRß impeded PDGFRß-positive cell migration to the tubular injury site and compromised the recovery of tubular function. CONCLUSIONS: Ablated tubular cells are exclusively replaced by resident tubular cell proliferation in a process dependent on PDGFRß-mediated communication between the renal interstitium and the tubular system.

25-Hydroxyl-protopanaxatriol protects against H2O2-induced H9c2 cardiomyocytes injury via PI3K/Akt pathway and apoptotic protein down-regulation.

Oxidative stress injury and apoptosis are the main mechanisms of myocardial ischemia-reperfusion injury (MI/RI). Compounds with anti-oxidant properties can treat MI/RI. Therefore, identification of natural antioxidants such as herbs or botanical drugs is an ideal strategy to develop safe and effective anti-MI/RI drugs. Cardioprotective effects of Ginseng are well documented and are attributable to its anti-oxidant, anti-inflammatory, anti-tumorigenic, anti-arrhythmic, anti-ischemic properties. Ginseng monomer 20®-dammarane -3 beta,6 alpha,12 beta,20,25-pentol(25-hydroxyl-Protopanaxatriol,25-OH-PPT), a novel compound, which belongs to panaxatriol category, is extracted from the leaves and stem of ginseng. It was first investigated for its anti-tumorigenic properties. In this study, we explored whether 25-OH-PTT plays a role in antioxidant stress injury and anti-apoptosis in cardiomyocytes. We also explored the mechanisms in order to provide a theoretical basis to develop 25-OH-PPT as a new drug for treatment of MI/RI. First, we used H2O2 to induce H9c2 cardiomyocytes in vitro resulting in an oxidative stress injury model and pretreated with 25-OH-PPT. Secondly, we examined the viability of H9c2 cells by MTT assay, the reactive oxygen species (ROS) content and mitochondrial membrane potential by flow cytometry as well as cell apoptosis by flow cytometry Annexin-FITC/PI and Hoechst 33258 staining. Furthermore, we pretreated H9c2 cells with PI3K inhibitor, LY294002, and observed the above phenomenon. Lastly, we examined the expressions of proteins related to the PI3K/Akt signaling pathway and the apoptotic proteins. We found that 25-OH-PPT can protect H9c2 cells against H2O2-induced injury, decrease apoptosis of H9c2 cells and ROS generation, and increase the mitochondrial membrane potential. It can also upregulate the protein expressions of p-Akt, p-eNOS, and Bcl-2 and down-regulate apoptotic proteins Bax and Caspase-3. Our results indicate that 25-OH-PPT inhibits H2O2-induced H9c2 cardiomyocytes injury through PI3K/Akt pathway. It may become a potential safe and effective traditional Chinese medicine monomer for treatment of MI/RI.

Therapeutic effects of a taurine-magnesium coordination compound on experimental models of type 2 short QT syndrome.

Short QT syndrome (SQTS) is a genetic arrhythmogenic disease that can cause malignant arrhythmia and sudden cardiac death. The current therapies for SQTS have application restrictions. We previously found that Mg· (NH2CH2CH2SO3)2· H2O, a taurine-magnesium coordination compound (TMCC) exerted anti-arrhythmic effects with low toxicity. In this study we established 3 different models to assess the potential anti-arrhythmic effects of TMCC on type 2 short QT syndrome (SQT2). In Langendorff guinea pig-perfused hearts, perfusion of pinacidil (20 µmol/L) significantly shortened the QT interval and QTpeak and increased rTp-Te (P<0.05 vs control). Subsequently, perfusion of TMCC (1-4 mmol/L) dose-dependently increased the QT interval and QTpeak (P<0.01 vs pinacidil). TMCC perfusion also reversed the rTp-Te value to the normal range. In guinea pig ventricular myocytes, perfusion of trapidil (1 mmol/L) significantly shortened the action potential duration at 50% (APD50) and 90% repolarization (APD90), which was significantly reversed by TMCC (0.01-1 mmol/L, P<0.05 vs trapidil). In HEK293 cells that stably expressed the outward delayed rectifier potassium channels (IKs), perfusion of TMCC (0.01-1 mmol/L) dose-dependently inhibited the IKs current with an IC50 value of 201.1 µmol/L. The present study provides evidence that TMCC can extend the repolarization period and inhibit the repolarizing current, IKs, thereby representing a therapeutic candidate for ventricular arrhythmia in SQT2.

Effect of trapidil in myocardial ischemia-reperfusion injury in rabbit.

OBJECTIVES: To evaluate the cardioprotective effects of trapidil on myocardial ischemia-reperfusion injury (MIRI) in rabbits. MATERIALS AND METHODS: Rabbits were subjected to 40 min of myocardial ischemia followed by 120 min of reperfusion. Blood for superoxide dismutase (SOD) and malondialdehyde (MDA) were estimated. At the end of reperfusion, the rabbits were sacrificed and the hearts were isolated for histological examination. An apoptotic index (AI) was determined using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end-labeling (TUNEL) method. The expression of apoptosis-related proteins Bax and Bcl-2 was analyzed using immunohistochemistry. Statistical analyses were performed by one-way analysis of variance (ANOVA), P < 0.05 considered statistically significant. RESULTS: Trapidil caused a significant (P < 0.05) increase in SOD activity, as decreased MDA levels and significantly (P < 0.05) reduced the expression of Bax as compared with the ischemia-reperfusion (IR) control group. CONCLUSION: Trapidil may attenuate the myocardial damage produced by IR injury and offer potential cardioprotective action.

Trapidil, a platelet-derived growth factor antagonist, inhibits osteoclastogenesis by down-regulating NFATc1 and suppresses bone loss in mice.

Trapidil, a platelet-derived growth factor antagonist, was originally developed as a vasodilator and anti-platelet agent and has been used to treat patients with ischemic coronary heart, liver, and kidney disease. In this study, we investigated the effects of trapidil on osteoclastogenesis and elucidated the possible mechanism of action of trapidil. Trapidil strongly inhibited osteoclast formation in co-cultures of bone marrow cells and osteoblasts without affecting receptor activator of NF-κB ligand (RANKL) or osteoprotegerin expression in osteoblasts. In addition, trapidil suppressed RANKL-induced osteoclast formation from osteoclast precursors. Trapidil reduced RANKL-induced expression of nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), a master transcription factor for osteoclastogenesis, without affecting the expression of c-Fos that functions as a key upstream activator of NFATc1 during osteoclastogenesis. Ectopic expression of a constitutively active form of NFATc1 reversed the anti-osteoclastogenic effect of trapidil, indicating that NFATc1 is a critical target of the anti-osteoclastogenic action of trapidil. RANKL-induced calcium oscillation and Pim-1 expression, which are required for NFATc1 induction and osteoclastogenesis, were abrogated by trapidil. Consistent with the in vitro results, trapidil had a potent inhibitory effect on osteoclast formation and bone resorption induced by interleukin-1 in an animal model. Taken together, our data demonstrate that trapidil abrogates RANKL-induced calcium oscillation and Pim-1 expression required for NFATc1 induction, thereby inhibiting osteoclastogenesis.

Effects of the antianginal drug trapidil on atrioventricular conduction disturbances during acute myocardial ischemia.

Adenosine and related compounds have been shown to produce atrioventricular (AV) conduction block during acute myocardial ischemia. We investigated the effects of the antianginal drug trapidil, which has been shown to inhibit phosphodiesterase, on AV conduction disturbances in a canine model of acute myocardial ischemia. In 35 anesthetized dogs, the AV node artery was cannulated and perfused with arterial blood. Adenosine (300 µg, 650 µg, or 1000 µg) was injected into the AV node artery. With administration of adenosine at 300 µg, 650 µg, or 1000 µg, the atrio-His (AH) interval was increased by 14.6 ms, 22.3 ms, and 29.7 ms, respectively. The effects of adenosine were potentiated by pretreatment with intravenous dipyridamole (250 µg/kg), an inhibitor of adenosine uptake, but the effects of adenosine were attenuated with intravenous trapidil (3 mg/kg), an inhibitor of phosphodiesterase. AV node artery occlusion resulted in prolongation of the AH interval in 4 of 12 dogs. The ischemia-induced AH prolongation was potentiated with intravenous dipyridamole and attenuated with intravenous trapidil. AV conduction disturbances associated with inferior myocardial infarction may be related in part to endogenously released adenosine, and trapidil may be useful in treating AV block associated with acute AV node ischemia.

The role of mast cells in parathyroid bone disease.

Chronic hyperparathyroidism (HPT) is a common cause of metabolic bone disease. These studies investigated the underlying cellular and molecular mechanisms responsible for the detrimental actions of elevated parathyroid hormone (PTH) on the skeleton. Bone biopsies from hyperparathyroid patients revealed an association between parathyroid bone disease and increased numbers of bone marrow mast cells. We therefore evaluated the role of mast cells in the etiology of parathyroid bone disease in a rat model for chronic HPT. In rats, mature mast cells were preferentially located at sites undergoing bone turnover, and the number of mast cells at the bone-bone marrow interface was greatly increased following treatment with PTH. Time-course studies and studies employing parathyroid hormone-related peptide (PTHrP), as well as inhibitors of platelet-derived growth factor-A (PDGF-A, trapidil), kit (gleevec), and PI3K (wortmannin) signaling revealed that mature mast cell redistribution from bone marrow to bone surfaces precedes and is associated with osteitis fibrosa, a hallmark of parathyroid bone disease. Importantly, mature mast cells were not observed in the bone marrow of mice. Mice, in turn, were resistant to the development of PTH-induced bone marrow fibrosis. These findings suggest that the mast cell may be a novel target for treatment of metabolic bone disease.

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.

Ischemia-reperfusion injury of rabbit ovary and protective effect of trapidil: an experimental study.

We aimed to detect the protective effect of trapidil in ischemia-reperfusion (IR) injury due to ovarian torsion and detorsion. Thirty-two pubertal New Zealand albino rabbits were used. Adnexal torsion was created by rotating the left adnexa including the tubal and ovarian vessels in a 360 degrees clockwise direction. Adnexal detorsion was done by untwisting the adnexa. In the IR group, left oopherectomy was performed after 3 h of adnexal torsion and 3 h of adnexal detorsion. In the study group, a 3-h adnexal torsion was performed and trapidil was administered intraperitoneally as a single dose of 40 mg/kg, 1 h before detorsion. The left oopherectomy was performed after a 3-h adnexal detorsion. In the sham group, sham operation was performed followed by left oopherectomy. In the control group, normal ovarian tissue was evaluated. Catalase, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels of ovarian tissue were determined for each group. The values of SOD and GSH-Px activities in the IR group were significantly decreased (P < 0.05). In addition, the MDA level was significantly higher in the IR group (P < 0.01). The trapidil-administered group showed significant increase in the levels of GSH-Px (P < 0.05), catalase (P < 0.05), SOD (P < 0.05), and decreased MDA levels (P < 0.05) compared to those in the IR group. The study has shown that trapidil treatment prevents ischemia induced oxidative damage in the ovarian tissues of rabbits.

Influence of systemically given placebo, trapidil and isosorbide dinitrate on norepinephrine-evoked hand vein constriction in healthy subjects.

Since trapidil (CAS 15421-84-8) is able to dilate human hand veins after local intravenous administration, four studies were carried out in healthy male volunteers using the dorsal hand vein compliance technique to test the influence of common systemic single doses of trapidil (200 mg orally, 100 mg intravenously) and isosorbide dinitrate (CAS 87-33-2, 20 mg orally) on norepinephrine (CAS 51-41-2)-evoked hand vein constriction in comparison with oral placebo. Oral placebo and oral trapidil were studied in a randomized double-blind cross-over design in 10 subjects aged 20 to 30 years, and oral isosorbide dinitrate and intravenous trapidil, in a randomized open cross-over design in 8 subjects aged 22 to 29 years. In the three similar studies with oral medications dose-response curves for venoconstriction by locally infused norepinephrine were established before and 1 h, 2 h and 3 h after oral medication and ED50 values of norepinephrine were calculated. The control dose-response curves and ED50 values of norepinephrine did not differ significantly. After oral placebo administration the dose-response curves of norepinephrine did not change significantly, but the ED50 of norepinephrine increased 3 h after placebo (from 12.1 to 31.7 ng/ min), indicating a lessening in norepinephrine effect at this time. After oral trapidil application the dose-response curves of norepinephrine shifted to the left compared with the pre-treatment curve (significantly 2 h after trapidil) and the corresponding curves after placebo with a significant decrease in the ED50 of norepinephrine 3 h after trapidil compared with placebo (from 31.7 to 12.6 ng/ min). After oral isosorbide dinitrate administration the dose-response curves of norepinephrine did not differ significantly from the pre-treatment curve, but they shifted to the left compared with the corresponding curves after placebo (significantly 3 h after isosorbide dinitrate). The ED50 of norephinephrine decreased significantly 2 h after isosorbide dinitrate compared with the pre-treatment value (from 9.4 to 3.3 ng/min) as well as 1 h, 2 h and 3 h after isosorbide dinitrate compared with placebo (from 32.4/21.3/31.7 to 7.3/3.3/6.0 ng/min). Therefore, oral trapidil and isosorbide dinitrate did not weaken norepinephrine-evoked hand vein constriction as expected but strengthened it slightly. Intravenously given trapidil led only to an insignificant short decrease followed by an insignificant increase in permanent venoconstriction due to local norepinephrine infusion. The data suggest that after systemic administration of trapidil or isosorbide dinitrate a hand vein constriction, which could be a reflex consequence of a drug-induced decrease in central venous pressure, exceeds an only discreet direct hand vein dilation.

CD40-CD40 ligand mediates the recruitment of leukocytes and platelets in the inflamed murine colon.

BACKGROUND AND AIMS: Although the CD40-CD40 ligand (CD40L) signaling pathway has been implicated in the pathogenesis of a variety of diseases, including inflammatory bowel disease, the nature of its contribution to intestinal inflammation remains poorly understood. The aim of this study was to determine whether CD40-CD40L contributes to the intestinal inflammatory response, tissue injury, and disease activity elicited by dextran sodium sulphate (DSS) through the modulation of leukocyte and platelet recruitment in the colonic microvasculature. METHODS: Wild-type (WT), CD40(-/-), and CD40L(-/-) mice were fed DSS drinking water. On day 6, intravital videomicroscopy was performed to monitor leukocyte and platelet recruitment in colonic venules, with measurements obtained for tissue myeloperoxidase and histology. CD40 expression on colonic endothelium was measured using the dual-radiolabeled antibody technique. RESULTS: A comparison of the responses to DSS-induced colitis in CD40(-/-) and CD40L(-/-) mice to WT mice revealed a significant attenuation of disease activity and histologic damage, as well as profound reductions in the recruitment of adherent leukocytes and platelets in the mutant mice. Similar down-regulation of the blood cell recruitment responses to DSS was noted in WT mice treated with the CD40-CD40L pathway inhibitor Trapidil. CD40 expression in the colonic vasculature was greatly elevated during DSS-induced inflammation in WT mice, but not in CD40(-/-) mice. CONCLUSIONS: These findings implicate CD40-CD40L in the pathogenesis of DSS-induced intestinal inflammation, and suggest that modulation of leukocyte and platelet recruitment by activated, CD40-positive endothelial cells in colonic venules may represent a major action of this signaling pathway.

Effect of locally applied trapidil on norepinephrine- and dinoprost-evoked hand vein constriction in healthy men.

OBJECTIVE: In this study the effect of locally administered trapidil on human hand veins was examined. SUBJECTS: 10 healthy male volunteers aged 20 - 30 years were included. METHOD: The dorsal hand vein compliance technique was used. In a crossover design the influence of locally infused trapidil (mainly 5 - 400 microg/min) on hand veins preconstricted with either norepinephrine (adrenoceptor agonist) or dinoprost (prostaglandin F2alpha) was investigated. Preconstriction reduced the vein diameter by about 80% with continuous local infusion of individually determined doses of norepinephrine in the range 11 - 1,000 ng/min and dinoprost in the range 90 - 5,600 ng/min. Blood pressure, cardiac function (electrocardiogram) and skin temperature of the hand infused were monitored. RESULTS: Locally applied trapidil produced a dose-dependent dilation of hand veins preconstricted with norepinephrine and dinoprost. The corresponding ED50 values of trapidil did not differ significantly on an intraindividual comparison. Clinically important side effects with the drugs used were not observed. CONCLUSIONS: The results indicate that trapidil has a direct dilating action on superficial veins in humans. This effect is apparently achieved without involvement of adrenoceptors or prostanoid receptors in venous smooth muscle.

Effects of trapidil on renal ischemia-reperfusion injury.

There is increasing evidence to suggest that reactive oxygen and nitrogen species play a role in the pathogenesis of renal ischemia-reperfusion (I/R) injury. This study was designed to determine the possible protective effects of trapidil treatment against oxidative and nitrosative tissue injury of kidney induced by I/R. A renal I/R injury was induced by a left renal pedicle occlusion by ischemia for 45 minutes, followed by 1 hour of reperfusion with contralateral nephrectomy in I/R and I/R + trapidil groups. Trapidil (8 mg/kg intravenously) was administrated immediately before reperfusion phase. At the end of the reperfusion period, rats were killed. Then, renal tissue samples were taken for biochemical analysis and histopathological evaluation, and blood samples were obtained to determinate serum urea, aspartate aminotransferase (AST), and tumor necrosis factor-alpha (TNF-alpha) levels. Ischemia-reperfusion injury caused significant increases in myeloperoxidase activity and malondialdehyde and 3-nitrotyrosine levels in renal tissue and elevated serum urea, AST, and TNF-alpha levels. In addition, severe deterioration of renal morphology was seen in the I/R group. Trapidil treatment significantly reduced in biochemical parameters, as well as serum urea, AST, and TNF-alpha levels. Furthermore, renal tissue injury was markedly attenuated with trapidil treatment. These data suggest that reactive oxygen species and reactive nitrogen species play a causal role in I/R-induced renal tissue, and trapidil has a renoprotective effect against oxidative and nitrosative kidney damage.

Trapidil decreases the aggregation of platelets from heart transplant recipients ex vivo.

Heart transplant recipients show platelet hyperaggregability, which may be related to the incidence of graft vasculopathy. We investigated whether trapidil can inhibit the aggregation of platelets from these patients. Platelet count, mean platelet volume (MPV), and adenosine diphosphate (ADP)-induced platelet aggregation were determined in 18 heart transplant recipients and 12 healthy subjects. Additionally, platelet-rich plasma from the patients was incubated with trapidil or with saline, prior to measuring ADP-induced aggregation. The MPV was significantly greater in patients compared to controls (9.4+/-1.1 vs 8.5+/-0.7 fL; P=.01), and ADP-induced platelet aggregation was significantly increased in patients compared to controls (81.2%+/-13.1% vs 69.6%+/-16.2%; P=.04, respectively). The trapidil-treated samples showed significantly decreased platelet aggregation compared to the control samples (24.2%+/-12.6% vs 66.7%+/-11.7%; P<.001). Platelets from heart transplant recipients showed an increased MPV and increased ADP-induced aggregation. Trapidil effectively reduced the ADP-induced aggregation ex vivo.

Protective effects of trapidil in ischemia-reperfusion injury due to testicular torsion and detorsion: an experimental study.

OBJECTIVE: We aimed to detect the preventive effects of trapidil in ischemia-reperfusion (IR) injury due to testicular torsion and detorsion. METHODS: Forty prepubertal albino rats were used. In the IR group, torsion was created by rotating the left testis over 2 h, and detorsion was done by untwisting the testis. Bilateral orchiectomies were performed after 4 h. In study group, 2-h torsion was performed and trapidil was administered as a single dose 1 h before detorsion. Bilateral orchiectomies were performed after 4 h. In the sham group, a sham operation was done. In the sham plus trapidil group, a sham operation was done and trapidil was administered as a single dose. Testicular tissue malondialdehyde (MDA), nitric oxide (NO) and total sulfhydryl (T-SH) levels were determined for each group. The grades of interstitial injury were determined in histopathologic examination. RESULTS: The NO and MDA levels in the IR group were significantly higher than the study, sham and sham plus trapidil groups in the left testis (P<0.05, P<0.001 and P<0.001, respectively). A statistical difference was not found among study, sham and sham plus trapidil groups in the left testis in NO and MDA levels (P>0.05). The T-SH level in the study group was significantly higher than in the IR, sham and sham plus trapidil groups in left testis P<0.05). In the IR group (left testis), grade 1 interstitial injury was 30% (3/10), grade 2 injury was 60% (6/10) and grade 3 injury was 10% (1/10). In the study group (left testis), grade 1 interstitial injury was 30% (3/10) and there was no injury in 70% (7/10). CONCLUSION: Trapidil decreased free oxygen radical formation in testicular torsion and detorsion, and attenuated histopathological damage in the ipsilateral twisted testis.