Cytoprotective effect of trimetazidine on 75 min warm renal ischemia-reperfusion injury in rats

Bentonite-in hypromellose-poloxamer sol-gel for corneal application of trimetazidine: Study of rheology and ocular anti inflammatory potential

Bentonite is reported to be used for extending ocular drug delivery safely in a controlled manner. Bentonite combined hydroxypropyl methylcellulose (HPMC)-poloxamer based sol-to-gel formulation has been developed for the prophylactic ocular anti-inflammatory effect of trimetazidine after corneal application. HPMC-poloxamer sol formulation was prepared incorporating trimetazidine to bentonite at 1: 2*10^-5 to 1:5*10^-6 ratios using cold method, and investigations were carried out in carrageenan-induced rabbit eye model. Pseudoplastic shear thinning behavior without any yield value and high viscosity at low shear rate were the positive attribute of the tolerability of the sol formulation after ocular instillation. Presence of bentonite nanoplatelets revealed more sustained in vitro release (~79-97 %) and corneal permeation (~79-83 %) over a period of 6 h in comparison to its absence. Prominent acute inflammation has been produced in the carrageenan-induced untreated eye, whereas the absence of ocular inflammation has been noticed in the previously sol-treated eye even after carrageenan injection. HPMC-poloxamer-based formulation exhibited stronger binding affinity (5.13 kcal/mol) in the presence of bentonite rather than its absence (3.99 kcal/mol), resulting in a stable and sustained effect. HPMC-poloxamer in-situ gel of trimetazidine containing bentonite could be utilized for sustained ocular delivery and the control of ophthalmic inflammation prophylactically.

MicroRNA-27a-3p aggravates renal ischemia/reperfusion injury by promoting oxidative stress via targeting growth factor receptor-bound protein 2

Renal ischemia-reperfusion (RI/R) injury with high morbidity and mortality is one common clinical disease. Development of drug targets to treat the disorder is critical important. MiR-27a-3p plays important roles in regulating oxidative stress. However, its effects on RI/R injury have not been reported. In this paper, hypoxia/reoxygenation (H/R) models on NRK-52E and HK-2 cells, and RI/R model in C57BL/6 mice were established. The results showed that H/R in vitro decreased cell viability and increased ROS levels in cells, and RI/R caused renal injury and oxidative damage in mice. The expression levels of miR-27a-3p were up-regulated based on real-time PCR and FISH assays in model groups compared with control groups, which directly targeted Grb2 based on dual luciferase reporter assay and co-transfaction test. In addition, miR-27a- 3p markedly reduced Grb2 expression to down-regulate the expression levels of p-PI3K, p-AKT, Nrf2, HO-1, and up-regulate Keap1 expression in model groups. MiR-27a-3p mimics in vitro enhanced H/R-caused oxidative stress via increasing ROS levels and decreasing Grb2 expression to down-regulate PI3K-AKT signal. In contrary, miR-27a-3p inhibitor in vitro significantly reduced H/R-caused oxidative damage via decreasing ROS levels and increasing Grb2 expression to up-regulate PI3K-AKT signal. In vivo, miR-27a- 3p agomir exacerbated RI/R-caused renal damage by decreasing SOD level and increasing Cr, BUN, MDA levels via suppressing Grb2 expression to down-regulate PI3K- AKT signal. However, miR-27a -3p antagomir alleviated RI/R-caused oxidative damage via increasing Grb2 expression to up-regulate PI3k-AKT signal. Grb2siRNA in mice further enhanced RI/R-caused renal injury by increasing Cr, BUN, MDA levels and decreasing SOD level via inhibiting the expression levels of Grb2, Nrf2, HO-1, and increasing Keap1 expression. Our data showed that miR-27a-3p aggravated RI/R injury by promoting oxidative stress via targeting Grb2, which should be considered as one new drug target to treat RI/R injury.

Effects of Post Ischemia-Reperfusion Treatment with Trimetazidine on Renal Injury in Rats: Insights on Delayed Renal Fibrosis Progression

Even after recovery from acute kidney injury, glomeruli remain vulnerable to further injury by way of interstitial fibrosis. This study is aimed at elucidating the effects of post ischemia-reperfusion (I/R) treatment with trimetazidine on the progression to renal fibrosis as well as short- and intermediate-term aspects. Trimetazidine 3 mg/kg or 0.9% saline was given intraperitoneally once upon reperfusion or daily thereafter for 5 d or 8 w. Renal histologic changes and related signaling proteins were assessed. After 24 h, post I/R treatment with trimetazidine significantly reduced serum blood urea nitrogen and creatinine levels and tubular injury accompanied with upregulation of hypoxia-inducible factor- (HIF-) 1α, vascular endothelial growth factor (VEGF), and Bcl-2 expression. After 5 d, post I/R treatment with trimetazidine reduced renal tubular cell necrosis and apoptosis with upregulation of HIF-1α-VEGF and tissue inhibitors of metalloproteinase activities, attenuation of matrix metalloproteinase activities, and alteration of the ratio of Bax to Bcl-2 levels. After 8 w, however, post I/R treatment with trimetazidine did not modify the progression of renal fibrosis. In conclusion, post I/R treatment with trimetazidine allows ischemic kidneys to regain renal function and structure more rapidly compared to nontreated kidneys, but not enough to resolute renal fibrosis in long-term aspect.

Predictive assessment of kidney functional recovery following ischemic injury using optical spectroscopy

Functional changes in rat kidneys during the induced ischemic injury and recovery phases were explored using multimodal autofluorescence and light scattering imaging. The aim is to evaluate the use of noncontact optical signatures for rapid assessment of tissue function and viability. Specifically, autofluorescence images were acquired in vivo under 355, 325, and 266 nm illumination while light scattering images were collected at the excitation wavelengths as well as using relatively narrowband light centered at 500 nm. The images were simultaneously recorded using a multimodal optical imaging system. The signals were analyzed to obtain time constants, which were correlated to kidney dysfunction as determined by a subsequent survival study and histopathological analysis. Analysis of both the light scattering and autofluorescence images suggests that changes in tissue microstructure, fluorophore emission, and blood absorption spectral characteristics, coupled with vascular response, contribute to the behavior of the observed signal, which may be used to obtain tissue functional information and offer the ability to predict posttransplant kidney function.

Trimetazidine Decreases Risk of Contrast-Induced Nephropathy in Patients With Chronic Kidney Disease

Objectives:

We sought to synthesize and analyze the available data from randomized controlled trials (RCTs) for trimetazidine (TMZ) in the prevention of contrast-induced nephropathy (CIN).

Background:

Contrast-induced nephropathy after coronary angiography is associated with poor outcomes. Trimetazidine is an anti-ischemic drug that might reduce incidence of CIN, but current data are inconclusive.

Methods:

We searched MEDLINE/PubMed, EMBASE, Scopus, Cochrane Library, Web of Science, and ScienceDirect electronic databases for RCTs comparing intravenous hydration with normal saline (NS) and/or N-acetyl cysteine (NAC) versus TMZ plus NS ± NAC for prevention of CIN. We used RevMan 5.2 for statistical analysis with the fixed effects model.

Results:

Of the 808 studies, 3 RCTs met criteria with 290 patients in the TMZ plus NS ± NAC group and 292 patients in the NS ± NAC group. The mean age of patients was 59.5 years, and baseline serum creatinine ranged from 1.3 to 2 mg/dL. Trimetazidine significantly reduced the incidence of CIN by 11% (risk difference 0.11; 95% confidence interval, 0.16-0.06; P < .01). There was no significant heterogeneity between the studies (I2 statistic = 0). The number needed to treat to prevent 1 episode of CIN was 9.

Conclusions:

The addition of TMZ to NS ± NAC significantly decreased the incidence of CIN in patients undergoing coronary angiography. In conclusion, TMZ could be considered as a potential tool for prevention of CIN in patients with renal dysfunction.

Impact of trimetazidine on incidence of myocardial injury and contrast-induced nephropathy in diabetic patients with renal dysfunction undergoing elective percutaneous coronary intervention

Trimetazidine is an anti-ischemic agent with antioxidant activity. This study evaluated the effect of periprocedural administration of trimetazidine on the incidence of percutaneous coronary intervention (PCI)-induced myocardial injury and contrast-induced nephropathy (CIN) in diabetic patients with mild-to-moderate renal dysfunction. One hundred patients with a mean glomerular filtration rate of 48 ± 16 (ml/min/1.73 m(2)) were prospectively enrolled, then randomly assigned to receive (50 patients; trimetazidine group) or not receive (50 patients; control group) periprocedural trimetazidine (70 mg/day) for 72 hours. The serum creatinine level was measured pre-PCI, 72 hours, and 10 days thereafter. An increase in the serum creatinine level by >0.5 mg/dl or 0.25% of the baseline value is considered as CIN. Cardiac troponin I levels were measured before and 6, 12, and 24 hours after PCI. Mean age of the study cohort was 59 ± 6 years (men 68%). The serum creatinine level in the control group increased significantly 3 days after PCI and decreased on the tenth day. However, it showed no significant change in the trimetazidine group. Incidence of CIN was 12% in the trimetazidine group and 28% in the control group (p <0.05). Cardiac troponin I levels were significantly reduced in the trimetazidine group (6 hours: 8 ± 0.3 vs 16 ± 0.2 pg/ml, 12 hours: 13 ± 0.9 vs 24 ± 0.8 pg/ml, 24 hours: 7 ± 0.7 vs 14 ± 0.3 pg/ml, p <0.001). In conclusion, trimetazidine intake before elective PCI in diabetic patients with mild-to-moderate renal dysfunction is associated with decreased incidence of CIN and myocardial injury.

Cardioprotective Effects of Oral Trimetazidine in Diabetic Patients With Anterior Wall Myocardial Infarction Treated with Thrombolysis

Background

Trimetazidine is an anti-ischemic agent with anti-oxidant activity. This study sought to evaluate the impact of oral trimetazidine on extent of myocardial damage in diabetic patients who were presented with anterior wall ST-segment elevation myocardial infarction (STEMI).

Methods

One hundred patients were prospectively enrolled, and then randomly assigned to receive oral trimetazidine (70 mg then 35mg bid) (group A, 50 patients) or placebo (group B, 50 patients), starting before thrombolysis. Serum creatine kinase-T and MB (CK-T and CK-MB) were measured serially. Degree of ST-segment resolution was recorded after 90 minutes. Left ventricle ejection fraction (LVEF) was assessed at baseline and after 6 months. Adverse events were recorded after thrombolysis and 6 months later.

Results

Mean age of the study cohort was 59.05 ± 3.8 years (males: 60%). After 24 hours, 45 (90%) patients in group A vs. 10 (20%) patients in group B showed peaking of CK-T and CK-MB levels (P < 0.05). Both biomarkers’ levels were significantly higher in the placebo group at different sampling times. Complete resolution of ST-segment elevation was recorded in 35 (70%) patients in group A vs. 18 (36%) patients in group B (P < 0.05). Six months later, group A showed higher LVEF and fewer cardiac adverse events (P < 0.05).

Conclusion

In diabetic patients receiving thrombolytic therapy for anterior wall STEMI, oral trimetazidine dosing was associated with less myocardial damage, earlier successful reperfusion, improvement of LVEF and less cardiac adverse events.

Trimetazidine for prevention of induced ischemia and reperfusion of guinea pig retina

OBJECTIVE

Trimetazidine (TMZ) has been used to protect against ischemia/reperfusion (I/R) injury of many tissues. We aimed to evaluate the effect of TMZ during retinal I/R in a guinea pig model.

STUDY DESIGN/PATIENTS AND METHODS

An experimental study in retinal I/R. Three groups of five guinea pigs were studied to include a control, placebo, and drug test groups. Prior to the application of 90 minutes of high intraocular pressure (IOP) to induce retinal ischemia followed by 24 hours of reperfusion, we applied intraperitoneal saline to the placebo group and 3 mg/kg of TMZ for the drug test group and repeated the injections at intervals of six hours for four cycles. Both eyes of the animals were enucleated at the end of the reperfusion period. Biochemical assay and histopathologic evaluation was performed on one randomly selected eye of each animal. The level of retinal-free malondialdehyde (MDA) and retinal layer thicknesses were determined and comparisons were then made with the control group.

RESULTS

The mean free MDA level increased in the placebo group (P = 0.006) but not in the drug group (P > 0.05). We observed polymorphonucleated leukocyte infiltration, retinal edema and hydropic degeneration in the retina of the placebo group. However, significant histopathologic change was not observed in specimens of the drug group.

CONCLUSIONS

This study suggests TMZ has a beneficial effect on retinal lipid peroxidation and histopathologic changes due to I/R injury.

Effects of trimetazidine on crush injury of the sciatic nerve in rats: a biochemical and stereological study

Trimetazidine (TMZ) is an anti-ischemic agent which has been used for years as an effective anti-anginal agent in cardiac patients. The aim of the study was to investigate the effect of TMZ on the level of malondialdehyde (MDA), nitric oxide (NO), glutathione (GSH), catalase (CAT), histopathological changes and the number of myelinated axons in a crush injury model of sciatic nerve in rats. In this study, 50 Wistar albino rats were used and the right sciatic nerves of all animals were injured. They were randomly divided into two groups equal in number, called treatment and non-treatment groups. The animals were subdivided into four subgroups, non-injury/non-treatment (left sciatic nerves of non-treatment animals, NI-NT) and non-injury/treatment (left sciatic nerves of treatment animals, NI-T) and injury/non-treatment (right sciatic nerves of non-treatment animals, I-NT) and injury/treatment (right sciatic nerves of treatment animals, I-T). At the end of the experiment, the bilateral sciatic nerves and blood samples collected from these animals were analyzed using histological, stereological and biochemical methods. There was a progressive increase in the serum level of GSH and progressive decrease in serum MDA levels in the treatment group. Progressive decrease in serum NO levels was observed in the treatment groups and it was statistically significant on day 14 (p<0.05) compared to the non-treatment group. The activities of CAT were low in the treatment groups on days 21 (p<0.05) and 42 (p<0.05). In the NI-NT group, some unimportant degenerative changes such as irregularity in myelin sheets were observed. Many pathologic changes in the I-NT group and some minimal degeneration in the I-T group were observed. TMZ treatment resulted in increases in the myelinated axon numbers by a range of 223 to 604 in the I-NT group compared to the I-T. In conclusion, TMZ appears to be beneficial for induction of axonal regeneration and myelination in healthy nerves as well as injured nerves.

Trimetazidine revisited: a comprehensive review of the pharmacological effects and analytical techniques for the determination of trimetazidine

Trimetazidine (TMZ) is an effective and well-tolerated antianginal drug that possesses protective properties against ischemia-induced heart injury. Growing interest in metabolic modulation in recent years urged an up-to-date review of the literature on TMZ. This review consists of two major sections: (1) comprehensive and critical information about the pharmacological effects, mechanism of action, pharmacokinetics, side effects, and current usage of TMZ, and (2) developments in analytical techniques for the determination of the drug in raw material, pharmaceutical dosage forms, and biological samples.

Comparison of protective effects of trimetazidine against experimental warm ischemia of different durations: early and long-term effects in a pig kidney model

Acute renal failure (ARF) is often the consequence of an ischemia-reperfusion injury (IRI) and associated with high mortality. Warm ischemia (WI) is a crucial factor of tissue damage, and tissue destruction led by ischemia-reperfusion (I/R) can impact the early and long-term functional outcome. Trimetazidine (TMZ) is an anti-ischemic drug. Previously, we already verified its protective effect on a cold-ischemic pig kidney model by directly adding TMZ into the preservation solution (Faure JP, Baumert H, Han Z, Goujon JM, Favreau F, Dutheil D, Petit I, Barriere M, Tallineau C, Tillement JP, Carretier M, Mauco G, Papadopoulos V, Hauet T. Biochem Pharmacol 66: 2241-2250, 2003; Faure JP, Petit I, Zhang K, Dutheil D, Doucet C, Favreau F, Eugene M, Goujon JM, Tillement JP, Mauco G, Vandewalle A, Hauet T. Am J Transplant 4: 495-504, 2004). In this study, we aimed to study the potential effect of TMZ pretreatment (5 mg/kg iv 24 h before WI) on the injury caused by WI for 45, 60, and 90 min and reperfusion in a WI pig kidney model. Compared with sham-operated (control) and uninephrectomized animals (UNX), TMZ pretreatment significantly reduced deleterious effects after 45 min, and particularly 60 and 90 min, of WI by improving the recovery of renal function and minimizing the inflammatory response commonly prevalent in ischemic kidney injury. Compared with controls (control group and UNX group), it was observed that 1) hypoxia-inducible factor-1 (HIF-1alpha) expression occurred earlier and with a higher intensity in the TMZ-treated groups; 2) the reduction of IRI during the first week following reperfusion was correlated with an earlier and greater expression of stathmin, which is involved in the process of tubular repair; and 3) the tubulointerstitial fibrosis was reduced, particularly after 60 and 90 min of WI. In conclusion, TMZ made the warm-ischemic kidneys more resistant to the deleterious impact of a single episode of I/R and reduced early and long-term subsequent damage.

Trimetazidine in the prevention of contrast-induced nephropathy after coronary procedures

OBJECTIVE

To evaluate the efficacy of trimetazidine (TMZ) in the prevention of contrast-induced nephropathy (CIN) in patients with high serum creatinine levels undergoing coronary angiography/angioplasty.

METHODS

TMZ (20 mg thrice daily) was administered orally for 72 h starting 48 h before the procedure. All patients were given intravenous saline (0.9%) at a rate of 1 ml/kg of body weight per hour for 24 h starting 12 h beforehand. Serum creatinine levels were measured before the procedure, 48 h and 7 days after the procedure. Increase in serum creatinine level exceeding 0.5 mg/day or one quarter of the basal value is considered as CIN. Venous blood samples for serum total antioxidant capacity (TAC) measurement were drawn before and after coronary angiography.

RESULTS

Basal serum creatinine levels and TAC were similar in TMZ and control groups. Serum creatinine levels in the control group increased significantly 2 days after the procedure, and returned to the baseline values on the seventh day. However, it did not change significantly on the second day, and even significantly decreased on the seventh day in the TMZ group. CIN developed in 2.5% (1/40) of patients in the TMZ group and in 16.6% (7/42) of patients in the control group (p<0.05). TAC values were not different between treatment groups.

CONCLUSION

TMZ along with isotonic saline infusion is more effective than isotonic saline alone in reducing the risk of CIN in patients with pre-existing renal dysfunction.

Effect of trimetazidine on the nucleotide profile in rat kidney with ischemia-reperfusion injury

Ischemia-reperfusion injury is often responsible for delayed graft function after transplantation. Trimetazidine (TMZ) is an antioxidant agent used to protect grafts from ischemia-reperfusion injury. The aim of the study was to examine the effect of TMZ on nucleotide profile in rat kidney with ischemia-reperfusion injury. The study was carried out on Wistar rats divided into two groups: animals treated with TMZ and control group receiving placebo. TMZ 10mg/kg/day was administrated for 30 days. Concentrations of adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), adenosine (Ado), guanosine triphosphate (GTP), guanosine diphosphate (GDP), guanosine monophosphate (GMP), guanosine (Guo), inosine monophosphate (IMP), inosine (Ino), hypoxanthine (Hyp), xanthine (Xan), uric acid (UA), uridine (Urd), nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) were determined in kidney tissues after ischemia-reperfusion using HPLC. The total adenine nucleotide concentration (TAN) and adenylate energy charge (AEC) were also determined. Moreover the kidneys were evaluated histologically. Tissue concentrations of ATP, ADP, AMP, TAN and AEC were significantly increased in kidneys from rats treated with TMZ in comparison with rats receiving placebo. Concentrations of products of nucleotide degradation: inosine (Ino), guanosine (Guo) and uridine (Urd), as well as oxypurines: Hyp and Xan, were significantly decreased in rats treated with trimetazidine. Moreover, significantly less pronounced acute tubular necrosis was observed in kidneys of rats treated with TMZ. These results suggest that trimetazidine protects against dephosphorylation of nucleotides and ischemic damage.

Nonsynergistic effects of trimetazidine and selenium combination therapy on renal ischemic-reperfusion injury in rats

Reactive oxygen species (ROS) have been postulated to play a major role in postischemic acute renal injury. Moreover, lipid peroxidation has been described as an important pathway of ROS-induced postischemic acute renal failure. To evaluate effects of selenium (Se) and trimetazidine (TMZ) on postischemic renal failure, renal tissue malondialdehyde (MDA) and superoxide dismutase (SOD) concentrations were measured in Wistar rats with ischemic renal failure. Treatment groups consisted of rats treated with TMZ (5 mg/kg orally) or Se (30 microg/kg orally) or TMZ+Se for 15 days. Ischemic groups consisted of rats with clamped left renal arteries for 1 hour. Before left renal arterial clamping, right nephrectomy was performed; after 24 hours, left nephrectomy was done. The animals were divided into 5 groups. Group 1 (n=7) was the nonischemic control group without treatment; Group 2 (n=6) was the ischemic control group treated with physiologic solution; Group 3 (n=5) received TMZ; Group 4 (n=5) received Se; and Group 5 (n=6) received TMZ+Se for 15 days. After TMZ and Se treatment, right renal tissue MDA significantly decreased in Groups 3-5 when compared with those in Group 1. There was no significant difference between nonischemic and ischemic renal tissue MDA in Groups 3, 4, and 5. Postischemic renal tissue SOD levels were higher than nonischemic levels in Group 3. In Groups 4 and 5, no significant differences were observed between nonischemic and ischemic renal tissue SOD levels. Moreover, total scores obtained from histopathologic evaluation of ischemic and nonischemic kidney samples in Groups 3, 4, and 5 were similar, but these scores in Group 2 were significantly different from those of Groups 3, 4, and 5. These results indicate that, under these study conditions, TMZ, Se, and TMZ+Se treatments prevent lipid peroxidation in ischemic and nonischemic renal tissue. Moreover, these treatments prevent histologic findings of postischemic-perfusion renal injury.

Novel cardioprotective effects of tetrahydrobiopterin after anoxia and reoxygenation: Identifying cellular targets for pharmacologic manipulation

OBJECTIVES

Contemporary cardioprotective strategies to prevent perioperative ischemia-reperfusion injury have focused on the l-arginine nitric oxide pathway. Tetrahydrobiopterin is an absolute cofactor required for the enzyme nitric oxide synthase and is thus a critical determinant of nitric oxide production. We hypothesized that ischemia-reperfusion results in diminished levels of tetrahydrobiopterin, which might represent a key cellular defect underlying endothelial and myocyte dysfunction after ischemia-reperfusion. To this aim, we examined the effects of tetrahydrobiopterin supplementation in (1) an in vivo experimental model of global ischemia-reperfusion and (2) an in vitro human ventricular heart cell model of simulated ischemia-reperfusion. Measures of endothelial function, oxidant production, cell survival, and cardiac function were used to assess outcome.

METHODS

In study 1 Wistar rats were divided into one of 2 groups (n = 10 per group). One group received tetrahydrobiopterin (25 mg x kg(-1) x d(-1) for 7 days), and the other group served as the control group. Hearts were subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion, and left ventricular developed pressure, left ventricular systolic pressure, and left ventricular end-diastolic pressure were determined by using the modified Langendorff technique. In study 2 we quantitated myocardial malondialdehyde, a marker of lipid peroxidation, in ventricular tissues from both groups of animals using butanol phase extraction and spectrophotometric analysis. In study 3 coronary vascular responses were determined in vascular segments of the left coronary artery in both groups of animals after ischemia-reperfusion. Endothelium-dependent and endothelium-independent vasodilatation to acetylcholine and sodium nitroprusside, respectively, were compared between groups. In study 4, using a human ventricular heart cell model of simulated ischemia-reperfusion, we studied the effects of tetrahydrobiopterin (20 micromol/L) on cellular injury (as assessed by means of trypan blue uptake).

RESULTS

After ischemia-reperfusion, myocardial dysfunction was evidenced by a decrease in left ventricular developed pressure and an increase in left ventricular end-diastolic pressure (P =.01 compared with baseline). Hearts from tetrahydrobiopterin-treated rats exhibited protection against ischemia-reperfusion injury (left ventricular developed pressure: 74 +/- 4 vs control 42 +/- 8 mm Hg, P =.01; left ventricular end-diastolic pressure: 12 +/- 3 vs 34 +/- 7 mm Hg, P =.01). Furthermore, tetrahydrobiopterin treatment attenuated the rise in malondialdehyde levels after ischemia-reperfusion (P =.01). After reperfusion, coronary endothelial function to acetylcholine was attenuated (P =.003 vs sham-treated mice), whereas responses to sodium nitroprusside remained unchanged. Tetrahydrobiopterin-treated rats exhibited an improvement in acetylcholine-mediated vasorelaxation (P =.01 vs ischemia-reperfusion group). Cellular injury, as assessed by means of trypan blue uptake, was higher in human ventricular heart cells subjected to simulated ischemia-reperfusion; this effect was prevented with tetrahydrobiopterin treatment (P =.001).

CONCLUSIONS

Supplemental tetrahydrobiopterin provides a novel cardioprotective effect on left ventricular function, endothelial-vascular reactivity, oxidative damage, and cardiomyocyte injury after ischemia-reperfusion injury and might represent an important cellular target for future operative myocardial protection strategies.

Oxidative stress-mediated renal dysfunction by cyclosporine A in rats: attenuation by trimetazidine

Cyclosporine A (CsA) is one of the first line immunosuppressants employed in the management of solid organ transplantation and autoimmune diseases. The clinical utility of CsA is limited by the frequent occurrence of chronic nephrotoxicity, characterized by tubular atrophy, interstitial fibrosis and progressive renal impairment. The pathogenesis of CsA nephrotoxicity is still not well delineated. Recent evidences suggest that reactive oxygen species (ROS) play an important role in CsA nephrotoxicity. The present study was designed to demonstrate the role of oxidative stress, its relation to renal dysfunction and to investigate the effect of trimetazidine (TMZ), an anti-ischemic agent with free radical scavenging property, in CsA-induced nephrotoxicity. TMZ (2.5 mg/kg, p.o., twice a day) was administered 24 h before and 21 days concurrently with CsA (20 mg/kg, s.c.). Tissue lipid peroxidation was measured as thiobarbituric acid reacting substances (TBARS). Renal function was assessed by measuring the plasma and urine creatinine concentrations, blood and urine urea nitrogen levels and the creatinine and urea clearances. Renal morphological alterations were assessed by histopathological examination of Hematoxylin-Eosin, PAS and Masson's trichome stained sections of the kidneys. CsA (20 mg/kg, s.c) administration for 21 days produced elevated levels of TBARS and decreased renal function as assessed by increased plasma creatinine, BUN and decreased creatinine and urea clearances as compared to vehicle treated rats. The kidneys of CsA treated rats showed severe striped interstitial fibrosis, arteriolopathy, glomerular basement thickening, tubular vacuolization and hyaline casts. TMZ (2.5 mg/kg) markedly reduced elevated levels of TBARS, significantly attenuated renal dysfunction and the morphological changes in CsA treated rats. These results clearly demonstrate the pivotal role of reactive oxygen species and their relation to renal dysfunction and point to the therapeutic potential of an anti-ischemic agent, trimetazidine, in CsA-induced nephrotoxicity.

Recipient treatment with trimetazidine improves graft function and protects energy status after lung transplantation

BACKGROUND

Ischemia-reperfusion injury remains an important obstacle to successful lung transplantation. Trimetazidine is an anti-ischemic drug that restores the ability of ischemic cells to produce energy and reduces the generation of oxygen-derived free radicals. The aim of this study was to assess the protective effect of trimetazidine after prolonged ischemia in lung transplantation.

METHODS

Rat single-lung transplantation was performed in 4 experimental groups (n = 5 each). In all groups, transplantation was performed after 18 hours of cold (4 degrees C) ischemia. All donor lungs were flushed with low-potassium dextran-glucose (LPDG) solution that also contained 500 microg/liter prostaglandin estradiol (E(1)). Groups studied included: Group I: flush solution was administered containing 10(-6) mol/liter trimetazidine (TMZ), neither donor nor recipient treatment given; Group II: donors were treated with 5 mg/kg intravenous TMZ 10 minutes prior to harvest, but the flush solution did not contain TMZ; Group III: recipients treated with 5 mg/kg intravenous TMZ 10 minutes before reperfusion, and flush solution contained 10(-6) mol/liter trimetazidine; Group IV: ischemic control group. After 2 hours of reperfusion, oxygenation was measured and lung tissue was frozen and assessed for adenosine triphosphate (ATP) content, myeloperoxidase (MPO) activity and thiobarbituric acid-reactive substances (TBARS). Peak airway pressure (PawP) was recorded throughout the reperfusion period.

RESULTS

Group III showed significantly higher levels of ATP content (11.1 +/- 5.01 pmol vs Group I, 3.36 +/- 1.8 pmol, p = 0.008; vs Group II, 4.7 +/- 1.9 pmol, p = 0.03; vs Group IV, 0.7 +/- 0.2 pmol, p = 0.008), better oxygenation (442.5 +/- 26.5 mm Hg, vs Group I, 161.06 +/- 54.5 mm Hg; vs Group II, 266.02 +/- 76.9 mm Hg; vs Group IV, 89.4 +/- 14.7 mm Hg, p = 0.008) and reduced lipid peroxidation (TBARS) (0.15 +/- 0.03 nmol/g; vs Group I, 1.04 +/- 0.76 nmol/g; vs Group II, 0.69 +/- 0.4 nmol/g; vs Group IV, 2.29 +/- 0.4 nmol/g, p = 0.008). PawP and MPO activity were comparable in the 4 study groups.

CONCLUSION

Recipient treatment with TMZ provided significant protection of energy status, better oxygenation and reduced lipid peroxidation. Our data suggest that TMZ may be an important adjunct in the prevention of post-transplant lung ischemia-reperfusion injury.

Mitochondria as target for antiischemic drugs

The cessation of blood flow followed by a reperfusion period results in severe damages to cell structures. This induces a complex cascade of events involving, more particularly, a loss of energy, an alteration of ionic homeostasis promoting H(+) and Ca(2+) build up and the generation of free radicals. In this context, mitochondria are highly vulnerable and play a predominant role in the cell signaling leading from life to death. This is why, recently, efforts to find an effective therapy for ischemia-reperfusion injury have focused on mitochondria. This review summarizes the pharmacological strategies which are currently developed and the potential mitochondrial targets which could be involved in the protection of cells.

Effect of trimetazidine on retinal ischemia/reperfusion injury in rats

PURPOSE

To investigate the effect of trimetazidine (TMZ), an antioxidant agent, on the ischemia/reperfusion (I/R) injury in rat retina histopathologically.

METHODS

The retinal I/R model was carried out by the 4-vessel occlusion method on Wistar albino rats. Twenty-one rats were divided into 7 groups, each comprising 3 rats. The animals in groups 1, 2 and 3 underwent 30 min of ischemia + 4 h of reperfusion and were treated by the administration of saline, TMZ before reperfusion and TMZ before ischemia, respectively. The animals in groups 4, 5 and 6 underwent 90 min of ischemia + 4 h of reperfusion and were treated in the same way as those in groups 1, 2 and 3, respectively. The 7th group was sham operated.

RESULTS

Thirty and 90 min of ischemia followed by 4 h of reperfusion induced retinal injury in the rat retina. Histopathologically, the inner plexiform and inner nuclear layers were the most affected parts. TMZ was able to reduce almost all retinal I/R damage when administered before ischemia. A cytoprotective effect of TMZ was partly observed in those animals which were treated before reperfusion.

CONCLUSION

TMZ seemed to have a protective effect against retinal I/R injury in rats.

Trimetazidine reduces renal dysfunction by limiting the cold ischemia/reperfusion injury in autotransplanted pig kidneys

Ischemia/reperfusion injury leads to delayed graft function, which is a major problem in kidney transplantation. This study investigated the effects of adding trimetazidine (TMZ) to the perfusate of cold-stored kidneys on the function of reperfused autotransplanted pig kidney. The left kidney was removed and cold-flushed with Euro-Collins (EC), or University of Wisconsin (UW) solutions with or without 10(-6)M TMZ and stored for 48 h at 4 degrees C. The kidneys were then autotransplanted and the contralateral kidneys were removed. Several parameters were analyzed over the 14 d after transplantation. The survival rate was 57% in pigs transplanted with kidneys cold-flushed with UW and 43% for those flushed with EC solution; it was 100% for pigs having kidneys cold-flushed with TMZ-supplemented UW and EC solutions. The functions of the transplanted kidneys were also better preserved after cold flush with TMZ-supplemented solutions than with TMZ-free solutions. Creatinine clearance was higher and the urinary excretion of trimethylamine-N-oxide and dimethylamine, used as markers of renal medulla injury, were lower in animals transplanted with kidneys cold-flushed with TMZ-supplemented solutions than with TMZ-free solutions. The cytoprotective action of TMZ also reduced interstitial and peritubular inflammation and the numbers of infiltrating mononuclear CD45+and CD3+ T cells. These results indicate that the tissue damage due to ischemia/reperfusion injury may be prevented, at least in part, by adding TMZ to preservation solutions.