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

Metabolic regulation to treat bipolar depression: mechanisms and targeting by trimetazidine

Bipolar disorder's core feature is the pathological disturbances in mood, often accompanied by disrupted thinking and behavior. Its complex and heterogeneous etiology implies that a range of inherited and environmental factors are involved. This heterogeneity and poorly understood neurobiology pose significant challenges to existing drug development paradigms, resulting in scarce treatment options, especially for bipolar depression. Therefore, novel approaches are needed to discover new treatment options. In this review, we first highlight the main molecular mechanisms known to be associated with bipolar depression-mitochondrial dysfunction, inflammation and oxidative stress. We then examine the available literature for the effects of trimetazidine in said alterations. Trimetazidine was identified without a priori hypothesis using a gene-expression signature for the effects of a combination of drugs used to treat bipolar disorder and screening a library of off-patent drugs in cultured human neuronal-like cells. Trimetazidine is used to treat angina pectoris for its cytoprotective and metabolic effects (improved glucose utilization for energy production). The preclinical and clinical literature strongly support trimetazidine's potential to treat bipolar depression, having anti-inflammatory and antioxidant properties while normalizing mitochondrial function only when it is compromised. Further, trimetazidine's demonstrated safety and tolerability provide a strong rationale for clinical trials to test its efficacy to treat bipolar depression that could fast-track its repurposing to address such an unmet need as bipolar depression.

The Effect of Enalapril, Losartan, or Not Antihypertensive on the Oxidative Status in Renal Transplant Recipients

The clinical and biochemical improvement observed in kidney transplant (RT) recipients is remarkable. The correct functioning of the allograft depends on various factors such as the donor's age, the alloimmune response, the ischemia-reperfusion injury, arterial hypertension, and the interstitial fibrosis of the allograft, among others. Antihypertensive drugs are necessary for arterial hypertension patients to avoid or reduce the probability of affecting graft function in RT recipients. Oxidative stress (OS) is another complex pathophysiological process with the ability to alter posttransplant kidney function. The study's objective was to determine the effect of the administration of Enalapril, Losartan, or not antihypertensive medication on the oxidative state in RT recipients at the beginning of the study and one year of follow-up. All patients included in the study found significant overexpression of the oxidative damage marker to DNA and the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx). In contrast, it was found that the determination of the total antioxidant capacity decreased significantly in the final determination at one year of follow-up in all the patients who ingested Enalapril and Losartan. We found dysregulation of the oxidative state characterized mainly by oxidative damage to DNA and a significant increase in antioxidant enzymes, which could suggest a compensatory effect against the imbalance of the oxidative state.

Beneficial effect of trimetazidine on folic acid-induced acute kidney injury in mice: Role of HIF-1α/HO-1

Acute kidney injury (AKI) is a complex syndrome associated with a decrease in renal function and a significant impact on patient outcomes. Injection of folic acid (FA) in mice is used for studying the pathogenesis of AKI. This study investigated the impact of trimetazidine (a metabolic modulator-antianginal drug; TMZ), against FA-induced AKI. AKI was induced by FA (250 mg/kg, ip) in mice. Two doses of TMZ were administered orally for 10 days. Administration of TMZ at a high dose (20 mg/kg) exhibited significant decreases in the renal somatic index (RSI), serum levels of lactate dehydrogenase (LDH), creatinine (Cr), blood urea nitrogen (1), and proteins level in urine. Moreover, TMZ significantly increased creatinine clearance (CCr), serum albumin, urine creatinine, and urine urea levels. This improvement in markers of kidney damage was associated with marked renal antioxidant effects (↓NO and ↓lipid peroxidation, normalized reduced glutathione (GSH) level and superoxide dismutase (SOD) activity, and increased HIF-1α/HO-1 level). Furthermore, TMZ significantly decreased FA-induced expression of MPO and inflammatory cytokine IL-18, TNF-α, and NF-κB p65 subunit. Renal apoptosis, along with apoptotic markers, were enhanced by FA injection and suppressed by TMZ administration (↓Caspase-3, ↓Bax, and ↑Bcl2 expression). Finally, TMZ amended FA-induced histopathological changes in kidneys. By mitigating functional alteration, oxidative stress, and preventing the development of inflammatory and apoptosis signals, TMZ provides dose-dependent defense against FA-induced AKI mainly via stimulation of hypoxia-inducible factor-1 alpha (HIF-1α)/heme oxygenase-1 (HO-1) pathway.

Trimetazidine an emerging paradigm in renal therapeutics: Preclinical and clinical insights

Trimetazidine (TMZ) is a well-known anti-ischemic agent used for the treatment of angina pectoris. In the past decades, the efficacy of this drug has been tested in a wide range of kidney injuries, including drug-induced nephrotoxicity (DIN), radio-contrast agent-induced nephropathy, and surgically induced renal ischemic injury. TMZhas renoprotective effects by attenuating oxidative stress, inflammatory cytokine release, maintaining oxygen and energy balance. Moreover, TMZ administration prevented kidney graft rejection in the porcine model by suppressing the infiltration of mononuclear cells, preserving mitochondrial functions, and maintaining Ca+ homeostasis. In DIN and diabetic kidney diseases,TMZ treatment prevents renal injury by inactivating immune cells, attenuating renal fibrosis, inflammation, apoptosis, and histological abnormalities. Interestingly, the clinical therapeutic efficacy of TMZ has also been documented in pre-existing kidney disease patients undergoing contrast exposure for diagnostic intervention. However, the mechanistic insights into the TMZ mediated renoprotective effects in other forms of renal injuries, including type-2 diabetes, drug-induced nephrotoxicity, and hypertension-induced chronic kidney diseases, remain uninvestigated and incomplete. Moreover, the clinical utility of TMZ as a renoprotective agent in radio-contrast-induced nephrotoxicity needs to be tested in a large patient population. Nevertheless, the available pieces of evidence suggest that TMZ is a promising and emerging renal therapy for the treatment and management of kidney diseases of variable etiologies. This review discusses the various pre-clinical and clinical findings and provides mechanistic insights into the TMZ mediated beneficial effects in various kidney diseases.

Effects of Chrysophyllum albidum fruit pulp on haemodynamic parameters, pro-inflammatory markers, antioxidant parameters and critical biomolecules associated with hypertension-in vivo

The effects of Chrysophyllum albidum fruit pulp on haemodynamic parameters, pro-inflammatory markers, antioxidant parameters and critical biomolecules associated with hypertension in vivo were determined. Feeding with supplemented diet with pulp reduced heart rate, mean arterial pressure, systolic and diastolic blood pressure levels of hypertensive-treated groups. Moreover, hypertensive-treated groups fed with fruit pulp supplemented diets had significantly (p < 0.05) lower level of serum pro-inflammatory markers when compared to untreated hypertensive group. Furthermore, feeding with supplemented diet with pulp and captopril administration reduced AChE, BChE, ACE, and arginase activities of hypertensive-treated groups. The fruit pulp supplemented diet also increased antioxidant status of hypertensive-treated groups. This was supported by the histopathological examination of the kidney and heart tissues. These beneficial effects could in part be the explanations of ethnomedicinal uses of the fruit pulp in the management of hypertension. Nevertheless, the higher percentage inclusion of the pulp showed higher antihypertensive effects.

Activators of SIRT1 in the kidney and protective effects of SIRT1 during acute kidney injury (AKI) (effect of SIRT1 activators on acute kidney injury)

Acute kidney injury (AKI) is a complex disorder and a clinical condition characterized by acute reduction in renal function. If AKI is not treated, it can lead to chronic kidney disease, which is associated with a high risk of death. SIRT1 (silent information regulator 1) is an NAD-dependent deacetylase. This enzyme is responsible for the processes of DNA repair or recombination, chromosomal stability, and gene transcription. This enzyme also plays a protective role in many diseases, including AKI. In this study, we review the mechanisms that mediate the protective effects of SIRT1 on AKI, including SIRT1 activators.

Extracts from Almond (Terminalia catappa) leaf and stem bark mitigate the activities of crucial enzymes and oxidative stress associated with hypertension in cyclosporine A-stressed rats

We investigated the effect of extracts from the leaf (ALE) and stem bark (ABE) of Almond tree on activities of some crucial enzymes [angiotensin-1 converting enzyme (ACE), arginase, acetylcholinesterase (AChE), phosphodiesterase-5 (PDE-5), adenosine deaminase (ADA), superoxide dismutase (SOD), catalase], and thiobarbituric acid reactive species (TBARS) associated with hypertension in normal adult male Wistar albino rats and Cyclosporine A (CsA)-stressed rats. The result revealed that CsA-stressed rats treated with captopril and extracts (ALE and ABE) had lowered ACE, arginase, AChE, PDE-5, ADA activities, and TBARS level, coupled with improved SOD and catalase activities compared with untreated CsA-stressed rats, which had reversed these biochemicals compared to normal rats. This suggests that the extracts could be explored to suppress hypertension and other cardiac injury known with CsA treatment; the potentials that could be linked with the constituent polyphenols. However, further studies including blood pressure should be determined to ascertain this claim. PRACTICAL APPLICATIONS: Drug-induced cardiotoxicity, hypertension, and organ damage are among the most common side effects of pharmaceutics. Therefore, it becomes imperative to find natural, effective, and alternative therapy with little or no side effect to combat drug toxicity. The use of Almond (leaf and stem bark) in folklore for the treatment/management of hypertension and other heart-related diseases without full scientific basis is on the increase. Hence, this study provides some biochemical evidences on the effect of Almond leaf and stem back extracts on crucial enzymes and oxidative stress markers involve in the incidence of hypertension in the course of Cyclosporine A administration. The findings of this study indicated that the studied plant materials could be promoted as nutraceutical agents to neutralize drug-induced cardiac injury and hypertension.

Trimetazidine Inhibits Renal Tubular Epithelial Cells to Mesenchymal Transition in Diabetic Rats via Upregulation of Sirt1

Trimetazidine (TMZ), as a metabolic regulator, is effective in treatment of coronary atherosclerotic heart disease with rare side effects in the clinic for long years. Interestingly, studies have shown that TMZ protects against several acute kidney injuries (AKI). However, the effect of TMZ on chronic kidney diseases (CKD) remains unknown. This study aimed to investigate the role of TMZ in diabetic nephropathy (DN) and its potential mechanisms. A rat model of DN was established in male Sprague-Dawley rats by streptozotocin (STZ) intraperitoneal injection. Experimental rats were separated into three groups: control, DN and DN + TMZ treatment. Metabolic parameters, pathological features and renal function markers were evaluated after 20 weeks of diabetes induction. In vitro experiments, the effect of TMZ on high fat and high glucose (HFG) induced or TGFβ1-induced epithelial-to-mesenchymal transition (EMT) was examined in HK-2 cells. Our results showed that TMZ could maintain renal function without affecting hemodynamic and plasma metabolic levels in diabetic rats. The effect was associated with a reversion of pathological progression of DN, especially for tubulointerstitial fibrosis. EMT is an important contributor to renal fibrosis. In this study, we investigated the role of TMZ in the process of EMT in DN. Mechanistically; TMZ attenuated HFG-induced EMT by relieving oxidative stress via deacetylation forkhead box O1 (FoxO1) in a Sirt1-dependent pathway. And it suppressed TGFβ1-induced EMT by deacetylating Smd4 in a Sirt1-dependent manner. Moreover, our study found that TMZ upregulated Sirt1 expression by increasing the expression of nicotinamide phosphoribosyl transferase (Nampt), which is a rate limiting enzyme for nicotinamide adenine dinucleotide (NAD⁺) generation by salvage pathway. And the increased NAD⁺ promoted Sirt1 expression. In conclusion, TMZ can prevent renal dysfunction and pathogenesis of tubulointerstitial fibrosis in DN, partly by inhibition of EMT via FoxO1/ROS pathway and TGFβ/Smad pathway in a Nampt/NAD⁺/Sirt1 dependent manner.

Cardio-protective and antioxidant properties of caffeic acid and chlorogenic acid: Mechanistic role of angiotensin converting enzyme, cholinesterase and arginase activities in cyclosporine induced hypertensive rats

Caffeic acid (CAA) and chlorogenic acid (CHA) are important members of hydroxycinnamic acid with natural antioxidant and cardio-protective properties. The present study aimed to determine the effect of CAA and CHA on systolic blood pressure, heart rates (HR) as well as on the activity of the angiotensin-1-converting enzyme (ACE), acetylcholinesterase (AChE), butrylcholinesterase (BChE) and arginase in cyclosporine-induced hypertensive rats. Experimental rats were distributed into 7 groups (n = 6): normotensive control rats; hypertensive rats (induced rats) as well as hypertensive- treated groups with captopril (10 mg/kg/day), CAA (10 and 15 mg/kg/day) and CHA (10 and 15 mg/kg/day), respectively. The experiment lasted for 7 days and the systolic blood pressure (SBP) and heart rates were recorded using tail-cuff method. Oral administration of captopril, caffeic acid and chlorogenic acid normalized hypertensive effect caused by cyclosporine administration. CAA and CHA significantly (P < 0.05) reduced SBP and HR, activity of ACE, AChE, BChE and arginase in the treated hypertensive rats compared with cyclosporine induced-hypertensive rats. Likewise, CAA and CHA improved nitric oxide (NO) bioavailability, increased catalase activity and reduced glutathione content while malondialdehyde (MDA) level was reduced compared with cyclosporine hypertensive rats. Findings from this study shows that CAA and CHA exhibited blood pressure lowering properties and reduced activities of key enzymes linked to the pathogenesis of hypertension in cyclosporine-induced rats. These might be some of the possible mechanisms of action by which their cardio-protective properties are exhibited.

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.

Calcineurin Inhibitor Nephrotoxicity Through the Lens of Longitudinal Histology: Comparison of Cyclosporine and Tacrolimus Eras

BACKGROUND

The contribution of calcineurin inhibitors (CNI) nephrotoxicity to progressive kidney transplant injury remains debated, with little long-term data from the modern tacrolimus (TAC) era using lower doses.

METHODS

This longitudinal cohort study evaluated histological evidence of CNI nephrotoxicity from normal donor kidneys of successful kidney-pancreas transplant recipients during cyclosporine (CSA) and TAC eras, analyzed by intention-to-treat.

RESULTS

From 200 patients, 1622 adequate prospective protocol (84.3%) and indication (15.7%) kidney biopsies yielded 8.1 ± 4.1 samples per patient, over 7.4 ± 4.4 years posttransplant. The TAC era demonstrated less rejection and reduced early immune-mediated tubular damage, compared with CSA (P < 0.001). The incidences of acute mild arteriolopathy, striped interstitial fibrosis, glomerular congestion, and tubular microcalcification were all greater with CSA (hazard ratios of 1.70, 9.35, and 3.78, respectively) and maximal within the first posttransplant year, compared with TAC-treated patients (P < 0.001). However, the 1-, 5-, and 10-year prevalence moderate arteriolar hyalinosis was similar: CSA was 5.4%, 38.4%, and 79.1%; and TAC was 4.3%, 33.6% and 77.2%, respectively (P = NS). Morphometric measurement demonstrated lumenal narrowing from inwards collapse of hyalinized arteriolar walls unable to maintain its structural integrity. Severe hyalinosis was calculated to reduce arteriolar blood flow to 20 ± 34% of normal. Severity of arteriolar hyalinosis correlated with contemporaneous glomerulosclerosis (r = 0.44, P < 0.001), and subsequent progression in 1356 sequential biopsy pairs, consistent with glomerular ischemia.

CONCLUSIONS

Tacrolimus-based therapy appeared superior to the CSA era, with less early CNI nephrotoxicity and fewer rejection episodes, but comparable chronic arteriolar toxicity. Calcineurin inhibitors are imperfect long-term maintenance immunosuppressive agents because of frequent and irreversible chronic toxicity.

The protective effect of trimetazidine against cisplatin-induced nephrotoxicity in rats

Nephrotoxicity is a dose-limiting side effect of cisplatin (CSP). The study investigated the possible protective role of trimetazidine (TMZ) against CSP-induced nephrotoxicity in rats. Rats were divided into four groups; control, TMZ, CSP, and CSP + TMZ. The CSP group showed significant deterioration in kidney function with structural changes in the form of interstitial hemorrhage, glomeruli shrinkage and peritublar capillary congestion, tubular cells vacuolation, pyknosis, shedding and necrosis, and inflammatory cell infiltrates, all indicating renal damage. CSP also caused a significant increase in the lipid peroxidation marker malondialdehyde (MDA) levels, renal nuclear factor kappa B (NF-κB) DNA-binding activity and protein expression, and tumor necrosis factor alpha (TNF-α) and IL-6 levels. Treatment with TMZ before and after CSP injection produced significant improvement of kidney function and histopathology. TMZ treatment also significantly attenuated CSP-induced oxidative stress and suppressed elevated levels of TNF-α and IL-6 and NF-κB expression and its DNA-binding activity caused by CSP administration. TMZ has a protective effect against CSP-induced nephrotoxicity mediated by reduction of oxidative stress and attenuation of CSP-induced inflammation.

Delayed treatment with oleanolic acid attenuates tubulointerstitial fibrosis in chronic cyclosporine nephropathy through Nrf2/HO-1 signaling

Background

Nuclear factor erythroid-2-related factor-2 (Nrf2) is known to protect against tissue injury by orchestrating antioxidant and detoxification responses to oxidative stress. This study investigated whether upregulation of Nrf2-dependent signaling by oleanolic acid (OA), which is known to activate Nrf2, could attenuate renal inflammation and fibrosis in cyclosporine (CsA)-induced kidney injury.

Methods

Male ICR mice were divided into four treatment groups: Vehicle (VH, n = 6), VH + OA (n = 6), CsA (n = 8), and CsA + OA (n = 8). For the OA-treated groups, OA (25 mg/kg/day) was administered by intraperitoneal injection for the final week of the 4-week experimental period. Renal function, morphologies and signaling were evaluated at the end of the study.

Results

Treatment with CsA resulted in decreased kidney function and urine osmolality and increased urine volume and urinary albumin levels. The CsA-induced changes were improved by OA treatment. Specifically, administration of OA decreased tubulointerstitial fibrosis and inflammation scores that were increased in CsA-treated mice. Furthermore, OA treatment decreased urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-epi-prostaglandin F2α (8-iso-PGF2α) levels. The beneficial effects of OA were attributed to an increased ratio of nuclear/total Nrf2 and subsequently enhanced expression of heme oxygenase (HO)-1, as well as a stable level of Kelch-like ECH-associated protein 1 (Keap1) expression, indicating that OA enhanced nuclear translocation of Nrf2. Increased apoptotic cell death and a high ratio of B cell leukaemia/lymphoma 2 (Bcl-2)-associated X protein (Bax) to Bcl-2 in CsA-treated mice were also significantly ameliorated by OA treatment.

Conclusion

Our results suggest that OA activates Nrf2/HO-1 signaling in chronic CsA nephropathy, which may have beneficial effects on inflammation and oxidative stress.

Oral administration of ginseng ameliorates cyclosporine-induced pancreatic injury in an experimental mouse model

Background

This study was performed to investigate whether ginseng has a protective effect in an experimental mouse model of cyclosporine-induced pancreatic injury.

Methods

Mice were treated with cyclosporine (30 mg/kg/day, subcutaneously) and Korean red ginseng extract (0.2 or 0.4 g/kg/day, oral gavage) for 4 weeks while on a 0.01% salt diet. The effect of ginseng on cyclosporine-induced pancreatic islet dysfunction was investigated by an intraperitoneal glucose tolerance test and measurements of serum insulin level, β cell area, macrophage infiltration, and apoptosis. Using an in vitro model, we further examined the effect of ginseng on a cyclosporine-treated insulin-secreting cell line. Oxidative stress was measured by the concentration of 8-hydroxy-2′-deoxyguanosine in serum, tissue sections, and culture media.

Results

Four weeks of cyclosporine treatment increased blood glucose levels and decreased insulin levels, but cotreatment with ginseng ameliorated the cyclosporine-induced glucose intolerance and hyperglycemia. Pancreatic β cell area was also greater with ginseng cotreatment compared with cyclosporine monotherapy. The production of proinflammatory molecules, such as induced nitric oxide synthase and cytokines, and the level of apoptotic cell death also decreased in pancreatic β cell with ginseng treatment. Consistent with the in vivo results, the in vitro study showed that the addition of ginseng protected against cyclosporine-induced cytotoxicity, inflammation, and apoptotic cell death. These in vivo and in vitro changes were accompanied by decreases in the levels of 8-hydroxy-2′-deoxyguanosine in pancreatic β cell in tissue section, serum, and culture media during cotreatment of ginseng with cyclosporine.

Conclusions

The results of our in vivo and in vitro studies demonstrate that ginseng has a protective effect against cyclosporine-induced pancreatic β cell injury via reducing oxidative stress.

Ginseng treatment attenuates chronic cyclosporine nephropathy via reducing oxidative stress in an experimental mouse model

BACKGROUND

This study was performed to investigate whether ginseng extract has a protective effect in an experimental mouse model of chronic cyclosporine (CsA) nephropathy.

METHODS

Mice were treated with CsA (30 mg/kg/day, subcutaneously) with or without Korean red ginseng extract (KRG) (0.2, 0.4 g/kg/day, orally) on a 0.01% salt diet for 4 weeks. The effect of KRG on CsA-induced renal injury was evaluated by assessing renal function and pathology, mediators of inflammation, tubulointerstitial fibrosis and apoptotic cell death. Using an in vitro model, we also examined the effect of KRG on CsA-treated proximal tubular cells (HK-2). Oxidative stress was measured by assessing 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in 24-hour urine, tissue sections, and culture media.

RESULTS

Four weeks of CsA treatment caused renal dysfunction, typical pathologic lesions and apoptotic cell death. KRG treatment reduced serum creatinine and blood urea nitrogen and histopathology and increased creatinine clearance. Proinflammatory and profibrotic molecules such as induced nitric oxide synthase, cytokines, transforming growth factor (TGF)-β1 and TGF-β1-inducible gene h3 and apoptotic cell death, also decreased with KRG treatment. Consistent with these results, in vitro studies showed that addition of KRG protected against CsA-induced morphological changes, cytotoxicity, inflammation, and apoptotic cell death as demonstrated by annexin V binding. These changes were accompanied by decrease in the level of 8-OHdG in urine and culture supernatant after KRG treatment.

CONCLUSION

The results of our in vivo and in vitro studies demonstrate that KRG has a protective effect in CsA-induced renal injury via reducing oxidative stress.

Protective effect of docosahexaenoic acid against cyclosporine A-induced nephrotoxicity in rats: a possible mechanism of action

The aim of this experimental study was to investigate whether, and how then, docosahexaenoic acid (DHA) could alleviate the cyclosporine A (CsA)-induced nephrotoxicity. Three main groups of Sprague-Dawley rats were treated orally with CsA (25 mg/kg), DHA (100 mg/kg), and CsA along with DHA. A corresponding control group was also used. DHA administration significantly reduced CsA-induced nephrotoxicity and associated hyperlipidemia and proteinuria as assessed by estimating serum triacylglycerol, serum total cholesterol, serum total protein, serum urea, and creatinine clearance. Furthermore, urinary excretions of protein and N-acetyl-β-D-glucosaminidase were significantly inhibited following DHA administration. DHA supplementation slightly attenuated the oxidative damage in kidney tissues as evaluated by the levels of thiobarbituric acid-reacting substances and protein carbonyl content in the kidney homogenate, although there were no significant differences between CsA-intoxicated and DHA-treated animals. Moreover, DHA treatment significantly restored total nitric oxide (NO) levels in both renal tissues and urine. This study demonstrates the ability of DHA to ameliorate CsA-induced renal dysfunction, which might be beneficial to enhance the therapeutic index of CsA. The data suggest that the protective potential of DHA in the prevention of CsA nephrotoxicity in rats was mainly associated with the increase of total NO bioavailability in renal tissues. Nevertheless, the exact independent mechanism in which DHA exerts its beneficial effect is yet to be fully elucidated.

Effect of Hyperbaric Oxygen on Cyclosporine-Induced Nephrotoxicity and Oxidative Stress in Rats

Reactive oxygen species have been suggested to be involved in cyclosporine nephrotoxicity. Hyperbaric oxygen is known to induce the generation of reactive oxygen species in tissues. The aim of this study was to investigate whether the use of hyperbaric oxygen concurrently with cyclosporine potentiates cyclosporine nephrotoxicity by inducing oxidative stress in kidneys. The study consisted of four groups of rats: a control group, a cyclosporine group (15 mg/kg/day intraperitoneally for 14 days), a hyperbaric oxygen group (60 min. every day for five days at 2.5 atmosphere absolute), and a cyclosporine + hyperbaric oxygen group (cyclosporine 15 mg/kg/day intraperitoneally for 14 days + hyperbaric oxygen for 60 min at 2.5 atmosphere absolute every day for five days on the last five days of cyclosporine treatment). Oxidative stress was determined by measuring renal thiobarbituric acid-reactive substances content, renal superoxide dismutase, and glutathione peroxidase activities. Cyclosporine increased serum urea and creatinine levels, indicating the development of nephrotoxicity, and induced significant oxidative stress in rat kidneys. Hyperbaric oxygen alone did not alter any of the biochemical and oxidative stress parameters compared to the control group. When used concurrently with cyclosporine, hyperbaric oxygen significantly reduced cyclosporine-induced oxidative stress, but it neither attenuated nor aggravated cyclosporine-induced nephrotoxicity. These results suggest that reactive oxygen species are involved in cyclosporine nephrotoxicity, but are not the direct cause of the toxicity. Although concurrent use of cyclosporine and hyperbaric oxygen did not exacerbate cyclosporine nephrotoxicity in this model, we recommend that the renal functions of patients be monitored periodically when these treatments are used concurrently.

Black Grape and Garlic Extracts Protect Against Cyclosporine A Nephrotoxicity

The aim of this study was to determine if the natural antioxidant foods, dried black grape and garlic, protect against cyclosporine nephrotoxicity. Forty-two Sprague-Dawley rats were given Cyclosporine A (CsA) orally for 10 days, with the antioxidant food supplementation begun 3 days before CsA treatment and continued during the study period (totaling 13 days). In each group (control, CsA alone, CsA plus black grape, CsA plus aqueous garlic extract, aqueous garlic extract alone and black grape alone), there were 7 animals. At the end of the study period, the animals were sacrificed; their kidneys were removed and prepared for biochemical and histopathological investigations. Oxidant (xanthine oxidase enzyme and malondialdehyde) and antioxidant (superoxide dismutase, glutathione peroxidase and catalase enzymes) parameters were measured in the kidney tissues of the groups. Histopathological examinations of the tissues were also performed. It has been found that CsA creates oxidant load to the kidneys through both xanthine oxidase activation and impaired antioxidant defense system, which accelerates oxidation reactions in the kidney tissue. Supplementation with either dried black grape or aqueous garlic extract led to reduced malondialdehyde level in the kidney tissue possibly, by preventing oxidant reactions. In conclusion, the results suggest that impaired oxidant/antioxidant balance may play part in the CsA-induced nephrotoxicity, and some foods with high antioxidant power may ameliorate this toxicity, in agreement with studies with antioxidant vitamins.

Attenuation of Cyclosporine-Induced Renal Dysfunction by Catechin: Possible Antioxidant Mechanism

One of great use of immunosuppressant, Cyclosporine-A (CsA) is in the solid organ transplantation; however the extensive use of this is cautionable due to its toxic effect in renal tissue, characterized by the tubular atrophy, interstitial fibrosis, and progressive renal impairment. However, there are many mediators are associated with pathogenesis of nephrotoxicity of CsA, the exact mechanism is still in debate. Recent studies indicate that Reactive Oxygen Species (ROS) induced oxidative stress and lipid peroxidations are the important mechanisms implicated in the pathophysiology of nephrotoxicity with CsA. In the present study we examined effect of dietary flavonoid catechin on oxidative damage in cyclosporine-A induced nephrotoxicity. Chronic administration of CsA (20 mg/kg/day) subcutaneously for 21 days significantly decreased the body weight as compared with vehicle treated rats. CsA (20 mg/kg/day) administration for 21 days significantly decreased the renal function by increase in the serum creatinine, blood urea nitrogen, and decrease in the creatinine and urea clearance as compared with vehicle treated rats. Catechin (100 mg/kg/day) for 21 days along with CsA significantly reversed the changed renal parameters, however lower dose of catechin (50 mg/kg/day) restored only increased serum creatinine levels as compared with CsA alone treated group. Biochemical analysis revealed that chronic administration of CsA (20 mg/kg/day) for 21 days significantly induced lipid peroxidation and decreased the glutathione levels in the kidney homogenate of rats. It is also observed that chronic CsA administered rats showed decrease in antioxidant defense enzyme superoxide dismutase and increase in the catalase activity as compared with vehicle treated rats. Co-administration of catechin (100 mg/kg/day) orally along with CsA for 21 days significantly reduced the lipid peroxidation and restored the decreased glutathione levels as compared with CsA alone group, but lower dose of catechin (50 mg/kg/day) restored only decreased glutathione levels induced by CsA. Co-administration of only higher dose of catechin (100 mg/kg/day) along with CsA significantly increased the superoxide dismutase (SOD) levels as compared with CsA alone treated group. It is also observed that catechin (100 mg/kg/day) along with CsA further increased the catalase levels as compared with CsA alone treated group, but not with lower dose of catechin. Animals administered with catechin (100 mg/kg/day) alone for 21 days showed significant increase in the catalase levels as compared with vehicle treated group. The major findings of the present study suggest that oxidative stress might play a significant role in CsA-induced nephrotoxicity. In conclusion, dietary administration of flavonoid catechin could be a useful component for the prevention/treatment of CsA-induced nephrotoxicity.

Influence of genetic polymorphisms in GSTM1, GSTM3, GSTT1 and GSTP1 on allograft outcome in renal transplant recipients

INTRODUCTION

Glutathione S-transferases (GSTs) are important in protection against xenobiotic compounds and toxicity caused by immunosuppressants in renal transplant recipients. In the present study we hypothesize that genetic variability in GSTM1, GSTM3, GSTP1 and GSTT1 genes may be associated with allograft outcome.

METHODS

The study included 223 controls and 273 transplant recipients categorized into 184 stable graft function (SGF), 57 rejection episodes (RE) and 32 delayed graft function (DGF). The polymorphism was studied using multiplex PCR and PCR-RFLP.

RESULTS

GSTM1 null genotype showed a 3.35-fold higher risk for rejection in SGF vs. RE category [95% confidence interval (CI) 1.27-8.84, p = 0.014]. Mutant (G) allele of GSTP1 was associated with a 5.52-fold risk for DGF (95% CI 1.37-22.17, p = 0.016). Kaplan-Meier analysis revealed significantly lower mean time to first RE in null genotype as compared with GSTM1 present patients (Log p = 0.002). The dose adjusted C(2) levels in null genotype was higher as compared with GSTM1 present patients at one (p = 0.007) and three months (p = 0.027) post transplantation.

CONCLUSION

Patients with variant genotype of GSTM1 and GSTP1 were at higher risk for rejection and delayed functioning of the allograft, respectively, supporting the hypothesis for involvement of GST isoform variants in allograft outcome in renal transplant recipients.

Effect of isoproterenol on cyclosporine-induced nephrotoxicity in rat

BACKGROUND

Oxidative stress is the main mechanism resulting in cyclosporine-induced nephrotoxicity. Because of its ability to stimulate endogenous melatonin production, isoproterenol is one of the most powerful antioxidant drugs. In this study, we sought to determine the effect of isoproterenol on cyclosporine-induced nephrotoxicity in rats.

MATERIALS AND METHODS

Thirty two young male Wistar rats were divided into four groups: of group A were controls that received placebo; group B, received intraperitoneal isoproterenol (20 mg/kg/d) alone; group C, intravenous cyclosporine (15 mg/kg/d) alone; and group D, both drugs simultaneously at the same doses and durations namely cyclosporine 1 week after administration of isoproterenol. Blood samples to measure serum urea, creatinine, and melatonin levels were drawn four times for each group: before injection, at the mid period of treatment, at the end of treatment, and 1 week after the last injections.

RESULTS

Isoproterenol increased mean serum melatonin level in groups B and D rats (P < .05). With regard to deteriorated renal function [DRF = (urea + creatinine)/2], administration of cyclosporine with (group D) or without (group C) isoproterenol was associated with decreased renal function (P < .05), although it was more perturbed in the latter instance. Measured DRF at the middle and the end of drug administration periods of A and B (revealed significant differences compared with groups C and D; P < .05).

DISCUSSION

Although cyclosporine-induced nephrotoxicity is not completely eliminated by isoproterenol, the latter showed some protective effects.

The effect of aldosterone antagonist in experimental nephropathy induced by cyclosporine A

This study evaluated the effect of spironolactone in the renal function alterations induced by cyclosporine A (CsA) in rats.

METHODS

Male Wistar rats fed with an unrestricted sodium diet received CsA 15 mg/kg/day or CsA at the same dosage plus 20 mg/kg/day of spironolactone. Another group received only saline. The animals that had proteinuria > 50 mg/24h or serum creatinine > 1.0 mg% were excluded, and after five weeks, the remaining rats were analyzed again for these parameters. At the end of the fifth week, these animals were also sacrificed, and their kidneys were analyzed histologically.

RESULTS

The animals that received CsA isolated or in association with spironolactone presented increase in serum creatinine. However, the comparison of the relative variation [Delta% = ([final - initial] / initial) x 100] of the serum creatinine concentrations in the beginning and at the end of the experiment among the animal groups showed a significant increase in the CsA group compared with the saline group (44.17 +/- 30.7% vs. -6.19 +/- 14.5%; p = 0.005), whereas there was no difference between the CsA + spironolactone and the saline group. In all of the animal groups, the values of 24-hour proteinuria were similar at the end of the experiment, and no renal histological alterations were observed.

CONCLUSION

This experimental model of nephrotoxicity by CsA in rats without salt restriction in the diet showed that CsA reduced the glomerular filtration and suggested that the blockage of aldosterone receptors prevented, at least partially, the reduction in renal function induced by CsA.

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.

Polymeric Micellar Delivery Reduces Kidney Distribution and Nephrotoxic Effects of Cyclosporine A After Multiple Dosing

The aim of this study was to test the ability of poly(ethylene oxide)-b-poly (epsilon-caprolactone) (PEO-b-PCL) micelles to reduce the renal uptake and nephrotoxicity of Cyclosporine A (CyA) after multiple dose administration. Sprague-Dawley rats received CyA i.v. at a dose of 20 mg/kg/day delivered as the commercial formulation (Sandimmune) or polymeric micellar formulation (PM-CyA). Cremophor EL (the solubilizing agent in Sandimmune), unloaded PEO-b-PCL micelles, or normal saline were also administered i.v. to control rats. After 7 days, kidney function was assessed through measurement of creatinine (CLcr) and urea clearances, as well as electrolyte concentrations in plasma. Blood and kidney were collected and assayed for CyA. Sandimmune administration led to decreased CLcr, and increased urea and potassium levels in plasma. In contrast, functional nephrotoxicity with the PM-CyA was not apparent, as the CLcr did not change significantly. The rate of increase in body weight in control rats was 3.1-3.4% per day. Weight gains (1.8% per day) were also noted in the rats given PM-CyA, although the body weight of animals receiving Sandimmune remained constant. Compared to Sandimmune, polymeric micelles reduced kidney uptake of CyA by 2.6-fold, and increased CyA levels in blood by 2.1-fold. The results show a potential for PEO-b-PCL micelles in restricting the nephrotoxicity of CyA.

Coordinated upregulation of a series of endogenous antioxidants and phase 2 enzymes as a novel strategy for protecting renal tubular cells from oxidative and electrophilic stress

In view of the crucial involvement of oxidative and electrophilic stress in various kidney disorders, this study was undertaken to test the hypothesis that pharmacologically-mediated coordinated upregulation of endogenous renal antioxidants and phase 2 enzymes is an effective strategy for renal protection. Notably, studies on the pharmacological inducibility of a series of antioxidants and phase 2 enzymes in renal tubular cells are lacking. Here we reported that incubation of normal rat kidney (NRK-52E) proximal tubular cells with low micromolar concentrations (10-50 microM) of the cruciferous nutraceutical, 1,2-dithiole-3-thione (D3T), led to a significant concentration-dependent induction of a wide spectrum of antioxidants and phase 2 enzymes, including catalase (CAT), reduced form of glutathione (GSH), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), NAD(P)H:quinone oxidoreductase 1 (NQO1), and heme oxygenase (HO). We further observed that D3T treatment also increased the protein and mRNA expression for CAT, gamma-glutamylcysteine ligase, GR, GST-A, GST-M, NQO1, and HO-1. Incubation of the renal tubular cells with H(2)O(2), SIN-1-derived peroxynitrite, or 4-hydroxy-2-nonenal led to concentration-dependent decreases in cell viability. Pretreatment of the renal tubular cells with 10-50 microM D3T afforded remarkable protection against the nephrocytotoxicity elicited by the above oxidative and electrophilic species. The D3T-mediated cytoprotection showed a concentration-dependent relationship. Taken together, this study for the first time comprehensively characterized the inducibility by a unique nutraceutical of a wide spectrum of antioxidative and phase 2 defenses in renal tubular cells at the levels of enzyme activity as well as protein and mRNA expression, and demonstrated that such a coordinated upregulation of cellular defenses led to remarkable protection of renal tubular cell from oxidative and electrophilic stress. Because of the crucial role of oxidative and electrophilic stress in inflammatory injury, D3T-mediated coordinated induction of endogenous antioxidative and phase 2 defenses may also serve as an important anti-inflammatory mechanism in kidneys.

Methotrexate and cyclosporine treatments modify the activities of dipeptidyl peptidase IV and prolyl oligopeptidase in murine macrophages

Analysis of the effects of cyclosporine A (25–28 mgkg⁻¹) and/or methotrexate (0.1 mgkg⁻¹) treatments on dipeptidyl peptidase IV (DPPIV) and prolyl oligopeptidase (POP) activities and on algesic response in two distinct status of murine macrophages (Mφs) was undertaken. In resident Mφs, DPPIV and POP were affected by neither individual nor combined treatments. In thioglycolate-elicited Mφs, methotrexate increased DPPIV (99–110%) and POP (60%), while cyclosporine inhibited POP (21%). Combined treatment with both drugs promoted a rise (51–84%) of both enzyme activities. Only cyclosporine decreased (42%) the tolerance to algesic stimulus. Methotrexate was revealed to exert prevalent action over that of cyclosporine on proinflammatory Mφ POP. The opposite effects of methotrexate and cyclosporine on POP activity might influence the availability of the nociceptive mediators bradykinin and substance P in proinflammatory Mφs. The exacerbated response to thermally induced algesia observed in cyclosporine-treated animals could be related to upregulation of those mediators.

Insights into the effects of hyperlipoproteinemia on cyclosporine A biodistribution and relationship to renal function

The purpose of this study was to assess the effect of hyperlipoproteinemia on the biodistribution of cyclosporine A (CyA), an extensively lipoprotein bound immunosuppressant, in a rat model and to determine the potential toxicological significance of this effect. Normolipidemic and hyperlipoproteinemic rats were given a single 5 mg/kg dose of CyA as intravenous bolus and at selected times postdose, tissues, blood, and plasma were harvested and assayed for CyA content. Hyperlipoproteinemia was induced by intraperitoneal injection of 1 g/kg poloxamer 407. Compared with normolipidemic animals, hyperlipoproteinemic rats had higher plasma, blood, kidney, and liver CyA concentrations. In contrast, in heart and spleen the concentrations were decreased in hyperlipoproteinemia. The nephrotoxic effect of CyA was also evaluated in normolipidemic and hyperlipoproteinemic rats after 7 days of dosing with 20 mg/kg/day. In both groups of animals, repeated doses of CyA were associated with equivalent decreases in creatinine and urea clearances compared with matching control and predose baseline measures. The concentrations of drug in kidney were equivalent at the conclusion of the study. However, despite these similarities there was microscopic evidence of more severe changes in the kidneys in the hyperlipoproteinemic rats, which also experienced a significant decrease in body weight compared with the normolipedemic animals. In conclusion, the distribution of CyA to kidneys was enhanced in poloxamer 407-induced hyperlipoproteinemic rats after single doses, and with repeated doses there was an apparent greater adverse effect on these animals compared with normolipidemic animals.

Renal damage in experimentally-induced cirrhosis in rats: Role of oxygen free radicals

Cirrhosis with ascites is associated with impaired renal function accompanied by sodium and water retention. Although it has been suggested that mediators such as nitric oxide play a role in the development of renal failure in this situation, other mechanisms underlying the process are not well understood. This study examined the role of oxidative stress in mediating renal damage during the development of cirrhosis in order to understand mechanisms involved in the process. It was shown that carbon tetrachloride- or thioacetamide-induced cirrhosis in rats results in oxidative stress in the kidney as seen by increased lipid peroxidation and protein oxidation, accompanied by altered antioxidant status. Cirrhosis was also found to affect renal mitochondrial function, as assessed by measurement of the respiratory control ratio, the swelling of mitochondria, and calcium flux across mitochondrial membranes. Increased lipid peroxidation and changes in lipid composition were evident in the renal brush border membranes, with compromised transport of 14C glucose across these membranes. In conclusion, renal alterations produced as a result of cirrhosis in the rat are possibly mediated by oxidative stress.

Renal and macrophage aminopeptidase activities in cyclosporin-treated mice

Cyclosporin, an immunosuppressive drug, is known to affect macrophage and to exert a nephrotoxic effect. Aminopeptidases play important roles for renal and macrophage functions. In this work, we attempt to test the hypothesis that the aminopeptidases participate within macrophage and renal effects induced by cyclosporin. Macrophage and renal aminopeptidase activities of cyclosporin-treated and control mice were evaluated, as well as renal caspase 3 activity, hematocrit, urinary protein and plasma osmolality, creatinine and uric acid concentrations. Cyclosporin treatment increased caspase 3 activity, hematocrit and osmolality, while urinary protein, creatinine and uric acid were unaltered. Soluble and particulate aminopeptidases in resident and elicited macrophages were unaffected by cyclosporin. The treatment with cyclosporin increased neutral, basic, cystyl, prolyl imino and pyroglutamyl soluble aminopeptidase activities in the renal cortex. Acid and basic soluble aminopeptidase activities increased in the renal medulla. Increased levels of particulate form in the cortex were detected for acid and pyroglutamyl aminopeptidase activities. Cyclosporin increased cortical soluble while decreased medullar particulate prolyl dipeptidyl aminopeptidase IV activity. With the exception of prolyl dipeptidyl aminopeptidase IV, particulate aminopeptidase activities returned to levels similar to controls after fifteen days of cyclosporin withdrawal, and soluble aminopeptidase activities did not regress. Our data indicate that the adopted regimen of cyclosporin treatment produced mild renal impairment with consistent changes on the levels of renal but not macrophage aminopeptidase activities. The obtained profiles of macrophage and renal aminopeptidase activities should be considered into the elaboration of new potential strategies for preventing nephrotoxicity during the treatment with cyclosporin.

Investigation of the Effect of Hyperbaric Oxygen on Experimental Cyclosporine Nephrotoxicity

Hyperbaric oxygen interacts with drugs which patients use concurrently with hyperbaric oxygen treatment, which may cause in potentiation or inhibition of both therapeutic and toxic effects. We examined the effect of hyperbaric oxygen therapy on experimental cyclosporine A nephrotoxicity. The study comprised four groups of rats: a control group, a cyclosporine A group (25 mg/kg/day intraperitoneally for four days), a hyperbaric oxygen group (60 min. every day for four days at 2.5 atmospheric pressure), and a cyclosporine A+hyperbaric oxygen group (CsA 25 mg/kg/day intraperitoneally for four days+hyperbaric oxygen for 60 min. every day for four days at 2.5 atmospheric pressure). Hyperbaric oxygen did not alter biochemical parameters. Cyclosporine A increased serum urea and serum creatinine levels and decreased creatinine clearance. In the cyclosporine A+hyperbaric oxygen group serum urea level increased more than in the cyclosporine A group. Cyclosporine A increased tubular epithelial cell apoptosis and necrosis score values. The numbers of apoptotic cells in proximal tubule epithelial cells in the cyclosporine A+hyperbaric oxygen group were significantly higher than those of the cyclosporine A group. We recommend that renal functions of the patients receiving cyclosporine A should be monitored during hyperbaric oxygen therapy.

Curcumin, a diferuloylmethane, attenuates cyclosporine-induced renal dysfunction and oxidative stress in rat kidneys

Background

In India, Curcumin (CMN) is popularly known as "Haldi", and has been well studied due to its economic importance. Traditional Indian medicine claims the use of its powder against biliary disorders, anorexia, coryza, cough, diabetic wounds, hepatic disorder, rheumatism and sinusitis. This study was designed to examine the possible beneficial effect of CMN in preventing the acute renal failure and related oxidative stress caused by chronic administration of cyclosporine (CsA) in rats. CMN was administered concurrently with CsA (20 mg/kg/day s.c) for 21 days. Oxidative stress in kidney tissue homogenates was estimated using thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) content, superoxide dismutase (SOD), and Catalase (CAT). Nitrite levels were estimated in serum and tissue homogenates.

Results

CsA administration for 21 days produced elevated levels of TBARS and marked depletion of renal endogenous antioxidant enzymes and deteriorated the renal function as assessed by increased serum creatinine, Blood Urea Nitrogen (BUN) and decreased creatinine and urea clearance as compared to vehicle treated rats. CMN markedly reduced elevated levels of TBARS, significantly attenuated renal dysfunction increased the levels of antioxidant enzymes in CsA treated rats and normalized the altered renal morphology.

Conclusion

In conclusion our study showed that CMN through its antioxidant activity effectively salvaged CsA nephrotoxicity.

Green tea extract attenuates cyclosporine A-induced oxidative stress in rats

Cyclosporine A (CsA) nephrotoxicity underweighs the therapeutic benefits of such a powerful immunosuppressant. Whether oxidative stress plays a role in such toxicity is not well delineated. We investigated the potential of green tea extract (GTE) to attenuate CsA-induced renal dysfunction in rats. Three main groups of Sprague-Dawley rats were used: CsA, GTE, and GTE plus CsA-receiving animals. Corresponding control groups were also used. CsA was administered in a dose of 20mg kg(-1) day(-1), i.p., for 21 days. In the GTE/CsA groups, the rats received different concentrations of GTE (0.5, 1.0 and 1.5%), as their sole source of drinking water, 4 days before and 21 days concurrently with CsA. The GTE group was treated with 1.5% concentration of GTE only for 25 days. A concomitant administration of GTE, to CsA receiving rats, markedly prevented the generation of thiobarbituric acid-reacting substances (TBARS) and significantly attenuated CsA-induced renal dysfunction as assessed by estimating serum creatinine, blood urea nitrogen, uric acid and urinary excretion of glucose. A considerable improvement in terms of reduced glutathione content and activity of antioxidant enzymes in the kidney homogenate of the GTE/CsA-receiving rats was observed. The activity of lysosomal enzymes, N-acetyl-beta-glucosaminidase, beta-glucuronidase and acid phosphatase was significantly inhibited following GTE co-administration. Our data prove the role of oxidative stress in the pathogenesis of CsA-induced kidney dysfunction. Supplementation of GTE could be useful in reducing CsA nephrotoxicity in rats. However, clinical studies are warranted to investigate such an effect in human subjects.

Evidence for protective roles of polyethylene glycol plus high sodium solution and trimetazidine against consequences of renal medulla ischaemia during cold preservation and reperfusion in a pig kidney model

BACKGROUND

The renal medulla is particularly sensitive to oxidant stress and to ischaemia-reperfusion injury (IRI). In organ transplantation, delayed graft function is an important problem and cold ischaemia is thought to be the most important factor in short- and long-term complications. Our aim was to study cold-induced damage in proximal tubular segments and renal medulla osmolite excretion during use of various preservation solutions, and to clarify the role of trimetazidine (TMZ) in limiting renal dysfunction.

METHODS

Using an autotransplanted pig kidney model, we assessed renal tubule function, medullary osmolite excretion and renal damage between day 1 and week 2 after 24 or 48 h cold storage in University of Wisconsin solution (UW), Celsior and ECPEG (two new high Na(+) preservation solutions) or the Hopital Edouard Herriot solution (HEH; a high Na(+) version of UW). In additional groups, TMZ was added to these preservation solutions for 24 and 48 h cold storage.

RESULTS

Renal function was reduced under these preservation conditions. Tubular injury was associated with aminoaciduria and with a limited Na(+) reabsorbtion. Medullary damage led to the early appearance of trimethylamine-N-oxide and dimethylamine in urine. However, renal damage was modulated by preservation conditions. In addition, TMZ added to each of the solutions efficiently protected against IRI even after prolonged preservation.

CONCLUSION

TMZ efficiently protected kidneys against damage when added to the HEH and particularly ECPEG solutions, even after 24 h cold storage. These findings point to a role for drugs that target mitochondria, and demonstrate that TMZ may provide a valuable therapeutic tool against IRI and could be included in therapeutic protocols.

Protective effect of FK506 (tacrolimus) in pentylenetetrazol-induced kindling in mice

The repeated administration of otherwise subconvulsant dose of pentylenetetrazol (PTZ) is known to produce chemical kindling in animals. In our study, chronic administration of subconvulsant dose of PTZ (40 mg/kg) produced chemical kindling in mice. Pretreatment with L-arginine (50-100 mg/kg ip) potentiated the PTZ-induced kindling, whereas N(omega)-nitro-L-arginine methyl ester (L-NAME) (10-20 mg/kg ip) showed a protective effect. FK506, a potent neuroprotective agent, dose dependently (0.5-1 mg/kg po) decreased the kindling score. When given in combination, L-NAME potentiated the protective effect of lower dose of FK506 (0.5 mg/kg) on PTZ-induced kindling. L-Arginine (50-100 mg/kg) reversed the protective effect of FK506 (1 mg/kg) and L-NAME (20 mg/kg). Biochemical studies showed the potential role of free radical toxicity in the kindled mice, as there was an increased lipid peroxidation as indicated by elevated malondialdehyde (MDA) and nitrite levels and decrease in GSH and superoxide dismutase (SOD) levels. FK506 pretreatment significantly reversed the elevated MDA and nitrite levels, GSH and SOD depletion induced by PTZ treatment. In conclusion, the results of the present study suggest the possible neuroprotective action of FK506 against PTZ-induced kindling.