Effect of N-acetylcysteine on gentamicin-mediated nephropathy in rats

A comprehensive review of the botany, ethnopharmacology, phytochemistry, and pharmacological activities of two Iranian Rydingia species (Lamiaceae)

Rydingia michauxii and R. persica, respectively, known as Kase Gol and Goldar in Persian, belong to the family Lamiaceae and they are well known herbal medicine in Iran for the treatment of various diseases, particularly diabetes. This review aims to appraise the phytochemistry, ethnopharmacology, and pharmacological activities of Rydingia species growing in Iran and assess their potential in clinical applications. Besides, it critically evaluates existing literature and looks into the perspective for further research and utilization. All available scientific literature was consulted using the database searches involving Google Scholar, PubMed, and Web of Science applying the keyword Rydingia and its Syn; Otostegia. Only the search results that are associated with the Iranian species R. michauxii and R. persica are included in this review. α-pinene, carvacrol, caryophyllene oxide, diisooctyl phthalate, dillapiole, eugenol, hexadecanoic acid, and pentacosane are the major constituents of the essential oils of the Rydingia species. Additionally, these species produce bioactive flavonoids, phenolic acids, steroids, and terpenoids. Extracts and active compounds from Rydingia species have been reported to possess various pharmacological activities including antidiabetic, anti-inflammatory, antimalarial, antimicrobial, antioxidant, cytotoxic, and lipid-lowering properties. Based on the information available to date on the Iranian Rydingia species, it will be worth subjecting these species to further developmental work involving preclinical and clinical trials.

Aronia melanocarpa (Michx.) Elliott 1821 Extract Has Moderate Ameliorative Influence on Biochemical and Hematological Parameters in Gentamicin-Induced Nephropathy in Wistar Rats

Gentamicin (GM) is an aminoglycoside antibiotic used to treat bacterial infections. Nephrotoxicity refers to the impairments of the kidneys caused by the use of GM and can result in decreased kidney function and in severe cases, kidney failure. Aronia melanocarpa extract (AME), also known as the black chokeberry, has been used for its protective effects on the kidneys. AME concentration of 3.38 mg/kg (max antioxidant activity in vitro) was used to determine its effectiveness against induced nephropathy during 30 days. GM treatment caused significant hypoalbuminemia and high values of globulins, creatinine, and urea compared to the control group. GM application lead to hemolysis occurrence, echinocytosis, and platelets aggregation. Significantly high values of segmented neutrophils and low values of non-segmented neutrophils were recorded in the blood of rats treated with chokeberry extract (AME). In the pre-treatment (AME + GM), severe hypochromic anemia and a significant improvement in hematological parameters, as well as a reduction of anemia in the post-treatment (GM + AME), were noted. Post-treatment AME also significantly regulates urea and creatinine values. Statistically significantly low hemoglobin values were found in all groups treated with AME. Current study suggests that compounds in the AME have a moderate beneficial effect against renal injury and anti-inflammatory properties that may help protect the kidneys from injury caused by GM.

Renal protective effect of N-acetylcysteine with stepwise ramping voltage against extracorporeal shock wave lithotripsy-induced renal injury: a prospective randomized trial

PURPOSE

To evaluate the role of combination of N-acetylcysteine with stepwise ramping voltage in renal protection against the ischemic, vascular and oxidative effects of extracorporeal shock wave lithotripsy.

PATIENTS AND METHODS

A prospective randomized trial on 164 adult patients scheduled for ESWL for single renal stones. Patients with radio-lucent stones, diabetes, hypertension, febrile UTI, and preoperative albuminuria were excluded from the study. Patients were randomized into one of four groups. Group A patients received maximal fixed voltage of ESWL. Group B patients received stepwise ramping voltage of ESWL. Group C patients received fixed maximal voltage with N-acetylcysteine (NAC) 600 mg/bid from 48 h before to 24 h after the procedure. Group D patients received gradual ramping voltage with NAC. Urinary β₂-microglobulin, 24 h albumin and N-acetyl-β-D-glucosaminidase/creatinine ratio at 1 day and 5 days post-ESWL and the stone free rate at 2 weeks were measured.

RESULTS

Group D was the only group that showed no significant difference pre and post ESWL in urinary albumin, β₂-microglobulin and N-acetyl-β-D-glucosaminidase/creatinine ratio. Post hoc analysis revealed no significant difference between group B and group C in albumin, β₂-microglobulin N-acetyl-β-D-glucosaminidase/creatinine ratio, but both of them had significantly lower levels than group A and significantly higher levels than group D. There was no statistically significant difference between all groups in the stone free rate at 2 weeks.

CONCLUSION

N-acetylcysteine protects the kidney against ESWL-induced renal injuries especially if combined with stepwise ramping voltage.

Protective effect of N-acetylcysteine against cisplatin ototoxicity in rats: a study with hearing tests and scanning electron microscopy

INTRODUCTION

Ototoxicity is a health problem appearing after powerful treatments in serious health conditions. It is sometimes inevitable when treatment of the serious disease is required. Cisplatin is an antineoplastic agent which was investigated previously to reveal increased nitrogen and reactive oxygen radicals that damages hair cells, resulting in ototoxicity. N-acetylcysteine, previously shown to decrease ototoxicity caused by different agents, is known to be a powerful in vitro antioxidant. Probably N-acetylcysteine, in addition to its antioxidant effect, blocks a cascade where reactive oxygen species result in apoptosis in the cochlea.

OBJECTIVES

The possible preventive effect of N-acetylcysteine in cisplatin ototoxicity was studied with auditory brain stem responses, otoacoustic emissions, and histopathological investigation of the cochlea in a scanning electron microscopy.

METHODS

This study was conducted on 21 Wistar Albino rats in four groups. 1mL/kg/day three times in total intraperitoneal (i.p.) Saline (n=5), 500mg/kg/day i.p. three times in total N-acetylcysteine (n=5), i.p. 15mg/kg cisplatin alone (single dose) (n=5) and i.p. 15mg/kg cisplatin plus 500mg/kg/day N-acetylcysteine (n=6) were administered. The rats were anesthetized to study the hearing tests before and after the experiment. The rats were sacrificed to investigate the cochleas by scanning electron microscopy.

RESULTS

Auditory brain stem responses and otoacoustic emissions values were attenuated in the cisplatin group. The group that received N-acetylcysteine in addition to cisplatin had better auditory brain stem responses thresholds and otoacoustic emissions. The samples obtained from the cisplatin group showed surface irregularities, degeneration areas, and total or partial severe stereocilia losses. The changes were milder in the cisplatin+N-acetylcysteine group.

CONCLUSION

Cisplatin ototoxicity can be detected by auditory brain stem responses and otoacoustic emissions testing in rats. N-acetylcysteine may protect the cochlear cells from histopathological changes. We concluded that N-acetylcysteine given 4h after cisplatin injection has a potential otoprotective effect against cisplatin ototoxicity. which suggests it could be used in clinical trials.

Protective effect of carnosine and N-acetylcysteine against sodium nitrite-induced oxidative stress and DNA damage in rat intestine

The widespread use of sodium nitrite (NaNO₂) as food preservative, rampant use of nitrogenous fertilizers for agricultural practices, and improper disposal of nitrogenous wastes have drastically increased human exposure to high nitrite levels causing various health disorders and death. In the present study, the protective effect of carnosine and N-acetylcysteine (NAC) against NaNO₂-induced intestinal toxicity in rats was investigated. Animals were given a single acute oral dose of NaNO₂ at 60 mg/kg body weight with or without prior administration of either carnosine at 100 mg/kg body weight/day for 7 days or NAC at 100 mg/kg body weight/day for 5 days. Rats were killed after 24 h, and intestinal preparations were used for the evaluation of biochemical alterations and histological abrasions. Administration of NaNO₂ alone decreased the activities of intestinal brush border membrane and metabolic enzymes and significantly weakened the anti-oxidant defense system. DNA damage was also evident as observed by increased DNA-protein crosslinking and fragmentation. However, prior administration of carnosine or NAC significantly ameliorated NaNO₂-induced damage in intestinal cells. Histological studies support these biochemical results, showing intestinal damage in NaNO₂-treated animals and reduced tissue injury in the combination groups. The intrinsic anti-oxidant properties of carnosine and NAC must have contributed to the observed mitigation of nitrite-induced metabolic alterations and oxidative damage. Based on further validation from clinical trials, carnosine and NAC can potentially be used as chemo-preventive agents against NaNO₂ toxicity.

N-Acetyl-L-Cysteine Protects Liver and Kidney Against Chromium(VI)-Induced Oxidative Stress in Mice

Acute hexavalent chromium [Cr(VI)] compound exposure may lead to hepatotoxic and nephrotoxic effects. Cr(VI) reduction may generate reactive intermediates and radicals which might be associated with damage. We investigated effects of N-acetyl-l-cysteine (NAC) pre- or post-treatment on oxidative stress and accumulation of Cr in liver and kidney of Cr(VI)-exposed mice. Intraperitoneal potassium dichromate injection (20 mg Cr/kg) caused a significant elevation of lipid peroxidation in both tissues as compared to control (p < 0.05). Significant decreases in non-protein sulfhydryl (NPSH) level, as well as enzyme activities of catalase (CAT) and superoxide dismutase (SOD) along with significant accumulation of Cr in the tissues (p < 0.05) were of note. NAC pre-treatment (200 mg/kg, ip) provided a noticeable alleviation of lipid peroxidation (p < 0.05) in both tissues, whereas post-treatment exerted significant effect only in kidney. Similarly, Cr(VI)-induced NPSH decline was restored by NAC pre-treatment in both tissues (p < 0.05); however, NAC post-treatment could only replenish NPSH in liver (p < 0.05). Regarding enzyme activities, in liver tissue NAC pre-treatment provided significant restoration on Cr(VI)-induced CAT inhibition (p < 0.05), while SOD enzyme activity was regulated to some extent. In kidney, SOD activity was efficiently restored by both treatments (p < 0.05), whereas CAT enzyme alteration could not be totally relieved. Additionally, NAC pre-treatment in both tissues and post-treatment in liver exerted significant tissue Cr level decreases (p < 0.05). Overall, especially NAC pre-treatment seems to provide beneficial effects in regulating pro-oxidant/antioxidant balance and Cr accumulation caused by Cr(VI) in liver and kidney. This finding may be due to several mechanisms including extracellular reduction or chelation of Cr(VI) by readily available NAC.

Effects of atorvastatin on biomarkers of acute kidney injury in amikacin recipients: A pilot, randomized, placebo-controlled, clinical trial

BACKGROUND

The most common clinical indication of aminoglycosides (AG) is the treatment of serious Gram-negative infections. The aim of this study was to evaluate plausible effects of atorvastatin on the biomarkers of acute kidney injury (AKI) in patients receiving amikacin.

MATERIALS AND METHODS

In this double-blinded randomized clinical trial, fifty patients (25 in each group) receiving amikacin (15 mg/kg/day) were randomly assigned to either atorvastatin (40 mg/day) or placebo (40 mg/day) groups for 7 days. Blood urea nitrogen (BUN), serum creatinine (SCr), and urinary neutrophil gelatinase-associated lipocalin (NGAL) levels were measured at days 0, 1, and 7 of amikacin treatment.

RESULTS

During the study period, 4 (8%) patients including two patients in each atorvastatin and placebo group experienced AKI. Urine NGAL/urine Cr did not change significantly between and within placebo and atorvastatin groups during the study period. Similarly, the mean changes in SCr, BUN, and urine NGAL/urine Cr values did not differ significantly between and within patients with and without AKI.

CONCLUSION

Our data suggested that the changing pattern of urine NGAL/urine Cr ratio did not differ significantly between the atorvastatin and placebo groups during the early phase of amikacin treatment.

A systematic meta-analysis on the efficacy of pre-clinically tested nephroprotectants at preventing aminoglycoside nephrotoxicity

Nephrotoxicity limits the use of aminoglycoside antibiotics. Kidney damage is produced mainly in the renal tubule due to an inflammatory and oxidative process. At preclinical level, many drugs and natural products have been tested as prospective protectors of aminoglycoside nephrotoxicity. The main objective of this work was to make a systematic literature review of preclinical studies about aminoglycoside nephrotoxicity protection and a statistical analysis based on the meta-analysis methodology. Studies published up to January 2016 were identified. After applying inclusion criteria, 54 studies were chosen. The size of the experimental groups, means and standard deviations of data on renal function (i.e. plasma creatinine and blood urea nitrogen [BUN] concentrations) were extracted and registered in a database. The studies were grouped according to the mechanism of nephroprotection and their route of administration. The Mean Difference (95% confidence interval) was calculated for each study and group. 40 of 54 products tested produced an amelioration of aminoglycoside nephrotoxicity based on creatinine results. Also a dose dependent protective effect was observed (both in creatinine and BUN). Products orally administered were more effective than via i.p. Products with attributed antioxidant activity were the most used and those which proved statistically significant nephroprotection as a class effect. Aminoglycoside tubular reuptake inhibitors, excretion inducers and calcium channel blockers also showed a promising and rather homogeneous class tendency towards nephroprotection, although more research is necessary to obtain solid and conclusive results, based on a larger number of studies.

Prevention of gentamicin ototoxicity with N-acetylcysteine and vitamin A

OBJECTIVE

To investigate the use of systemic N-acetylcysteine and vitamin A in the prevention of gentamicin ototoxicity in rats.

METHODS

Forty-two Wistar rats were divided into four groups according to treatment: intratympanic saline, intratympanic gentamicin, intraperitoneal vitamin A after intratympanic gentamicin, and intraperitoneal N-acetylcysteine after intratympanic gentamicin. Signal-to-noise ratio and distortion product otoacoustic emissions were evaluated in all groups.

RESULTS

N-acetylcysteine had a significant protective effect at 1.5, 2, 3, 4, 6 and 8 kHz, whilst vitamin A had a significant protective effect at 2, 3, 4 and 6 kHz, as determined by the distortion product otoacoustic emission measurements. According to the signal-to-noise measurements, N-acetylcysteine had a significant protective effect at 1.5, 2, 3, 4, 6 and 8 kHz, whilst vitamin A had a significant protective effect at 3, 6 and 8 kHz.

CONCLUSION

Gentamicin-induced hearing loss in rats may be prevented by the concomitant use of vitamin A and N-acetylcysteine. Specifically, N-acetylcysteine appeared to have a more protective effect than vitamin A for a greater range of noise frequencies.

Pinocembrin attenuates gentamicin-induced nephrotoxicity in rats

Oxidative stress mediated apoptosis of renal tubular cells is a major pathology of gentamicin-induced nephrotoxicity, which is one of the prevailing causes of acute renal failure. Pinocembrin is a major flavonoid found in rhizomes of fingerroot (Boesenbergia pandurata). It has pharmacological and biological activities including antimicrobial, anti-inflammatory, and antioxidant effects. Preclinical studies have suggested that pinocembrin protects rat brain and heart against oxidation and apoptosis induced by ischemia–reperfusion. The aim of the current study was to investigate the mechanisms of renoprotection elicited by pinocembrin in gentamicin-induced nephrotoxicity. Nephrotoxicity was induced in rats by intraperitoneal injection (i.p.) of gentamicin, and pinocembrin was administered via i.p. 30 min before gentamicin treatment for 10 days. Gentamicin-induced nephrotoxicity was indicated by the reduced renal function and renal Oat3 function and expression. Gentamicin treatment also stimulated Nrf2, HO-1, and NQO1, as well as the pro-apoptotic proteins Bax and caspase-3, concomitant with the attenuation of Bcl-XL expression in the renal cortical tissues. Pinocembrin pretreatment improved renal function and renal Oat3 function and reduced oxidative stress and apoptotic conditions. These findings indicate that pinocembrin has a protective effect against gentamicin-induced nephrotoxicity, which may be due in part to its antioxidant and anti-apoptotic effects, subsequently leading to improved renal function.

Effects of N-acetyl cysteine on renal functions evaluated by blood neutrophil gelatinase-associated lipocalin levels in geriatric patients undergoing coronary artery bypass grafting

Objective:

Recent conflicting studies on the renal effects of N-acetyl cysteine (NAC) after cardiac surgery have been published. The aim of this study was to evaluate the renal effects of NAC using neutrophil gelatinase-associated lipocalin (NGAL) blood levels in elderly patients undergoing coronary artery bypass grafting (CABG).

Methods:

This randomized, double-blinded, placebo-controlled study was conducted among geriatric patients (>65 years) scheduled to undergo CABG. A total of 60 consecutive patients were randomly assigned to 2 groups. The first group received I.V. NAC (n=30) and the second group received placebo (n=30) at induction of anesthesia and then for 20 h. NGAL values were determined and conventional renal function tests were performed. Statistical analysis was performed using SPSS 17.0 (IL, Chicago, USA). A p value of <0.05 was considered statistically significant

Results:

Plasma creatinine levels at 24 h postoperatively were significantly higher in the placebo group than in the NAC group (1.41±0.63 vs. 1.13±0.35; p<0.05). The mean serum NGAL levels at 3 h postoperatively were higher in the placebo group than in the NAC group (104.94±30.51 vs. 87.82±25.18; p<0.05). NGAL levels were similar between the groups at all other measurement time points. Plasma creatinine levels of ≥1.5 mg/dL or >25% of the baseline value at any time during the study period were observed in 27% of patients in the NAC group and 37% of patients in the placebo group; the difference was statistically significant (p<0.05).

Conclusion:

In the present study, we found that I.V. NAC infusion in elderly patients undergoing CABG reduced the incidence of acute kidney injury as determined by blood NGAL and creatinine levels.

Protective effects of N-acetylcysteine against hyperoxaluria induced mitochondrial dysfunction in male wistar rats

The purpose of the present study was to evaluate the nephro-protective potential of N-acetylcysteine against hyperoxaluria-induced renal mitochondrial dysfunction in rats. Nine days dosing of 0.4 % ethylene glycol +1 % ammonium chloride, developed hyperoxaluria in male wistar rats which resulted in renal injury and dysfunction as supported by increased level of urinary lactate dehydrogenase, calcium, and decreased creatinine clearance. Mitochondrial oxidative strain in hyperoxaluric animals was evident by decreased levels of superoxide dismutase, glutathione peroxidase, glutathione reductase, reduced glutathione, and an increased lipid peroxidation. Declined activities of respiratory chain enzymes and tricarboxylic acid cycle enzymes showed mitochondrial dysfunction in hyperoxaluric animals. N-acetylcysteine (50 mg/kg, i.p.), by virtue of its -SH reviving power, was able to increase the glutathione levels and thus decrease the oxidative stress in renal mitochondria. Hence, mitochondrial damage is, evidently, an essential event in ethylene glycol-induced hyperoxaluria and N-acetylcysteine presented itself as a safe and effective remedy in combating nephrolithiasis.

N-acetyl cysteine in prevention of amphotericin- induced electrolytes imbalances: a randomized, double-blinded, placebo-controlled, clinical trial

PURPOSE

The aim of this study was to evaluate the effectiveness of oral n-acetyl cysteine, as a potential nephroprotective agent, in preventing and/or attenuating amphotericin B-induced electrolytes imbalances.

METHODS

During a one year period, patients were to receive conventional amphotericin b for any indication for at least one week and were randomly allocated to receive either placebo or 600 mg oral n-acetyl cysteine twice daily during the treatment course of amphotericin b. Demographic and clinical data of the study population were gathered. Different aspects of amphotericin b nephrotoxicity including decrease of glomerular filtration rate, hypokalemia, hypomagnesemia, renal magnesium and potassium wasting were assessed. Each patient was monitored for any adverse reaction to n-acetyl cysteine. Sixteen and 14 patients in the n-acetyl cysteine and placebo groups completed the study, 3incidences of hypokalemia (75 % versus 70 %; P = 0.724) and hypomagnesemia (30 % versus 20 %; P = 0.468) did not differ significantly between placebo and NAC groups, respectively. Although the rate of AmB nephrotoxicity was higher in the placebo than in the NAC group (60 % versus 40 %), this difference was not statistically significant (P = 0.209) even after adjusting for probable associated factors of amphotericin b nephrotoxicity (P = 0.206). The incidence as well as time of onset of electrolyte abnormalities also did not differ significantly between placebo and n-acetyl cysteine groups. About 44 % of n-acetyl cysteine recipients experienced new onset nausea and a mild unpleasant taste during the study.

CONCLUSION

Oral n-acetyl cysteine during the amphotericin B treatment course was not significantly effective in preventing or mitigating different features of its nephrotoxicity including decrease of glomerular filtration rate, hypokalemia, hypomagnesemia, and renal potassium as well as magnesium wasting.

Protective Effects of Houttuynia cordata Thunb. on Gentamicin-induced Oxidative Stress and Nephrotoxicity in Rats

Development of a therapy providing protection from, or reversing gentamicin-sulfate (GS)-induced oxidative stress and nephrotoxicity would be of great clinical significance. The present study was designed to investigate the protective effects of Houttuynia cordata Thunb. (HC) against gentamicin sulfate-induced renal damage in rats. Twenty-eight Sprague-Dawley rats were divided into 4 equal groups as follows: group 1, control; group 2, GS 100 mg/kg/d, intraperitoneal (i.p.) injection; group 3, GS 100 mg/kg/d, i.p. + HC 500 mg/kg/d, oral; and group 4, GS 100 mg/kg/d i.p. + HC 1000 mg/kg/d, oral administration). Treatments were administered once daily for 12 d. After 12 d, biochemical and histopathological analyses were conducted to evaluate oxidative stress and renal nephrotoxicity. Serum levels of creatinine, malondialdehyde (MDA), and blood urea nitrogen (BUN), together with renal levels of MDA, glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) were quantified to evaluate antioxidant activity. Animals treated with GS alone showed a significant increase in serum levels of creatinine, BUN, and MDA, with decreased renal levels of GSH, SOD, and CAT. Treatment of rats with HC showed significant improvement in renal function, presumably as a result of decreased biochemical indices and oxidative stress parameters associated with GS-induced nephrotoxicity. Histopathological examination of the rat kidneys confirmed these observations. Therefore, the novel natural antioxidant HC may protect against GSinduced nephrotoxicity and oxidative stress in rats.

Role of diuretics and lipid formulations in the prevention of amphotericin B-induced nephrotoxicity

PURPOSE

To collect available clinical data to define the role of diuretics and lipid formulations in the prevention of amphotericin B (AmB)-induced nephrotoxicity (AIN) in human populations.

METHOD

A literature search was performed in the following databases: Scopus, Medline, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews.

RESULTS AND CONCLUSION

Co-administration of mannitol failed to show any clinically significant benefit in preventing AIN. Potassium-sparing diuretics, such as amiloride and spironolactone, have been shown to have beneficial effects as an alternative or adjunct to oral/parenteral potassium supplements in preventing hypokalemia due to AmB. Lipid-based formulations of AmB are clinically effective and safe in preventing AIN. However, due to their high cost and limited accessibility, these formulations are generally used as second-line antifungal therapy in cases of conventional AmB refractoriness and/or intolerance or pre-existing renal dysfunction. The potential effects of other nephroprotective agents, such as N-acetylcysteine, AIN merit further considerations and investigations.

Protective effect of N-acetylcysteine on kidney as a remote organ after skeletal muscle ischemia-reperfusion

PURPOSE: To investigate whether N-acetylcysteine has a protective effect against renal injury as a remote organ after skeletal muscle ischemia-reperfusion in rats. METHODS: Twenty Wistar male rats were divided randomly into two experimental groups: group ischemia-reperfusion (group I) and group ischemia-reperfusion + N-acetylcysteine (group II). After ketamine and xylazine anesthesia, femoral artery was exposed. All animals were undergone 2h of ischemia by occlusion femoral artery and 24h of reperfusion. Rats that were treated with N-acetylcysteine given IV at a dose of 150 mg/kg-¹, immediately before reperfusion. After 24h of reperfusion, the blood samples were collected and submitted for evaluation of plasmatic urea, creatinine values and then rats were euthanized and left kidney harvested for histopathological analysis under light microscopy. RESULTS: The urea (35±7.84 mg.dL-1), creatinine (1.46±0.47 mg.dL-1) values were significantly lower in group II (P=0.000). Renal histopathologic study in group I showed extensive distal and proximal tubular cells necrosis and sloughing of epithelial cells into the tubular lumen, cast formation in tubule and glomerul, glomerul fibrosis and hemorrhage. Histopathologically, there was a significant difference (p=0.037) between two groups. CONCLUSION: The N-acetylcysteine was able to decrease renal injury induced by skeletal muscle ischemia reperfusion in rats.

Nephroprotective activity of Macrothelypteris oligophlebia rhizomes ethanol extract

CONTEXT

Macrothelypteris oligophlebia (Bak.) Ching (Thelypteridaceae) is a Chinese herbal medicine used traditionally for the treatment of diseases such as edema, boils, burns, and roundworms. However, research about the nephroprotective potential of this plant is not available.

OBJECTIVE

Present study was designed to evaluate the protective effect of ethanol extract of M. oligophlebia rhizomes (EMO) on gentamicin (GM)-induced nephrotoxicity.

MATERIALS AND METHODS

Rats were intraperitoneal (i.p.) injected with GM (100 mg/kg) to induce nephrotoxicity and simultaneously EMO (250 and 500 mg/kg) was orally given to GM-treated rats for 8 days. Blood urea nitrogen (BUN), serum creatinine (Cr), malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were evaluated in renal tissues. Histopathological analysis was used for evaluation of the renal damage.

RESULTS

Administration with GM-induced renal dysfunction in rats. Pre-treatment with EMO (500 mg/kg) significantly decreased the levels of BUN, Cr, MDA and NO (decreased BUN from 12.71 ± 1.28 to 7.19 ± 0.23 mmol/l, Cr from 39.77 ± 5.34 to 19.17 ± 0.90 μmol/l, MDA from 5.60 ± 0.37 to 2.63 ± 0.24 nmol/ml, and NO from 868.17 ± 22.67 to 589.51 ± 8.83 μmol/ml), and also restored the activities of renal antioxidant enzymes (SOD, CAT, and GSH-Px) (restored SOD from 1.59 ± 0.17 to 2.94 ± 0.13 U/mg protein, CAT from 3.22 ± 0.34 to 10.57 ± 0.27 U/mg protein, and GSH-Px from 9.11 ± 1.29 to 20.72 ± 1.83 U/mg protein).

DISCUSSION AND CONCLUSION

Our results suggest that the rhizomes of M. oligophlebia potentially have a protective role in renal tissue against oxidative stress in acute renal failure.

[Allele-specific therapy: suppression of nonsense mutations by readthrough inducers]

Ten percent of human hereditary diseases are linked to nonsense mutations (premature termination codon). These mutations lead to premature translation termination, trigger the synthesis of a truncated protein and possibly lead to mRNA degradation by the NMD pathway (nonsense mediated mRNA decay). For the past ten years, therapeutic strategies have emerged which attempt to use molecules that facilitate tRNA incorporation at premature stop codon (readthrough), thus allowing for the synthesis of a full length protein. Molecules currently used for this approach are mostly aminoglycoside antibiotics (gentamicin, amikacin…) that bind the decoding center of the ribosome. This therapeutic approach has been studied for various genetic diseases including Duchenne muscular dystrophy (DMD) and cystic fibrosis. The feasibility of this approach depends on induced readthrough level, mRNA quantity, re-expressed protein functionality and characteristics of each disease.

Cytogenetic damage after ischemia and reperfusion

Tourniquets are often used to provide a bloodless operating field. However, they carry the risk of adverse effects caused by DNA damage from the free radicals generated during postischemic reperfusion of the blood. The aim of this study was to evaluate the cytogenetic damage caused by postischemic reperfusion on peripheral lymphocytes of five women and six men undergoing total knee arthroplasty "bloodless" operation using samples received before, during, immediately, and 1 h after the operations. The sister chromatid exchange assay was applied to peripheral blood lymphocyte cultures and the levels of sister chromatid exchanges were analyzed as a quantitative index of genotoxicity, along with the values of mitotic index and proliferation rate index as qualitative indices of cytotoxicity and cytostaticity, respectively. We observed that postischemic reperfusion induced cytogenetic damages specifically through reperfusion. DNA effects were most pronounced after tourniquet release and declined afterward without returning to preischemic baseline values. Our findings suggest the presence of a functional association between postischemic reperfusion and cytogenetic damage that may have important clinical implications.

N-acetylcysteine improves residual renal function in peritoneal dialysis patients: a pilot study

BACKGROUND

Preservation of peritoneal membrane function and residual renal function is important for the optimal care of peritoneal dialysis patients. N-Acetylcysteine may ameliorate oxidative stress, which is thought to be involved in peritoneal membrane dysfunction. In addition, N-acetylcysteine may have a positive effect on renal function in the setting of nephrotoxic contrast media administration. The aim of this study was to investigate the effect of N-acetylcysteine on peritoneal and residual renal function in peritoneal dialysis patients.

METHODS

Ten prevalent peritoneal dialysis patients were administered oral N-acetylcysteine 1200 mg twice daily for 4 weeks. At baseline and at the end of treatment, peritoneal membrane function and residual renal function were assessed using a 4.25% dextrose peritoneal equilibration test and 24-hour dialysate and urine collection for calculation of peritoneal and residual renal Kt/V and mean urea and creatinine residual renal clearance.

RESULTS

No significant changes were demonstrated in peritoneal membrane function, including dialysate-to-plasma creatinine ratio, sodium sieving, and net ultrafiltration. Residual renal function improved significantly: urine volume increased from 633 ± 426 to 925 ± 552 mL/24 hours (p = 0.022), residual renal Kt/V increased from 0.56 ± 0.41 to 0.75 ± 0.47 (p = 0.037), and mean residual urea and creatinine clearance increased from 4.96 ± 3.96 to 5.95 ± 4.08 mL/min/1.73 m(2) (p = 0.059).

CONCLUSIONS

N-acetylcysteine may improve residual renal function in patients treated with peritoneal dialysis.

Pentoxifylline ameliorates glomerular basement membrane ultrastructural changes caused by gentamicin administration in rats

Gentamicin is commonly used for the treatment of severe gram negative bacterial infections but inevitably cause renal failure during prolonged use. The aim of our study was to emphasize protective effects of pentoxifylline on glomerular basement membrane (GBM) alterations induced by gentamicin in rats. Experiments were done on 40 male Wistar rats divided in three experimental groups. GM-group was treated daily with gentamicin in dose of 100 mg/kg during 8 days. PTX-group was treated daily with pentoxifylline in dose of 45 mg/kg and the same dose of gentamicin as in GM-group during 8 days. The control group received 1 ml/day saline intraperitoneally. Morphometric parameter measured during the analysis was glomerular basement membrane thickness. In GM-group of animals glomeruli were enlarged and GMB was diffusely and unequally thickened with neutrophil cells infiltration. In proximal tubules epithelial cells, vacuolization of cytoplasm with coagulation-type necrosis were observed. In PTX-group of animals glomeruli were somewhat enlarged and GBM was thickened only in some segments. Coagulation-type necrosis was not found. Blood urea and serum creatinine concentration in GM-group were significantly elevated in comparison with PTX-group while potassium level was decreased. Our results suggest that PTX has protective effects on GBM and proximal tubules in GM-treated rats.

Potentially detrimental effects of N-acetylcysteine on renal function in knee arthroplasty

Ischaemia/reperfusion induces systemic inflammation and oxidative stress and thereby remote organ injury in the kidney. In a double-blind, placebo-controlled clinical trial of 30 patients undergoing knee arthroplasty with tourniquet, this study evaluated the effect of N-acetylcysteine (NAC) infusion on renal function by measuring urine alpha-1-microglobulin, N-acetyl-beta-D-glucosaminidase (NAG), glutathione-S-transferase-alpha and -phi and serum creatinine and cystatin C concentrations up to 24 h post-operatively. Compared to the baseline, urine alpha-1-microglobulin/creatinine increased in both groups and was higher in the NAC group than in the placebo group at tourniquet deflation and at 3 h thereafter. Urine NAG/creatinine increased at deflation and at 3 h thereafter in the NAC group and the ratio was higher than in the placebo group. The two sensitive indicators of proximal tubular damage and function used in the present study suggest that use of NAC in clinical setting of ischaemia/reperfusion injury may increase the risk of remote kidney injury.

Comparative protective effect of N-acetyl cysteine and tetramethylpyrazine in rats with gentamicin nephrotoxicity

Gentamicin (GM) is used against serious and life-threatening infections, but its use is limited by the occurrence of nephrotoxicity, which involves the generation of free radicals. In this work we tested the effect of a compound with antioxidant properties, tertamethylpyrazine (TMP), a major constituent of the Chinese medicinal plant Lingusticum wallichi, on GM-induced nephrotoxicity, and compared it with an established anti-oxidant compound N-acetyl cysteine (NAC). Six groups of rats were studied: (1) control, treated orally (p.o.) and intraperitoneally (i.p.) with saline; (2) treated i.p. with GM (80 mg kg(-1) per day for 6 days); (3) TMP, given p.o. (100 mg kg(-1) per day for 10 days) + GM (same dose as above during the last 6 days); (4) NAC, given i.p. (500 mg kg(-1) per day for 10 days) + GM as above; (5) TMP (100 mg kg(-1) per day for 10 days) + saline; (6) NAC (500 mg kg(-1) per day for 10 days) + saline. GM nephrotoxicity was characterized by reduced creatinine clearance, increased creatinine and urea concentrations in plasma, increased urinary excretion of N-acetyl-beta-d-glucosaminidase (NAG) and total protein. These functional and structural alterations were prevented or ameliorated by NAC treatment, while TMP had only a slight mitigating effect that was less marked than that produced by NAC. The concentration of GM in the renal cortex of the rats given GM + NAC (but not TMP) was lower than that found in rats treated with GM alone by about 25%. The mechanism by which NAC and, to a lesser extent TMP, protected against GM-induced nephrotoxicity may be related, at least in part, to the decrease in oxidative stress in renal cortex.

Amikacin-Induced Nephropathy: Is There Any Protective Way?

Amikacin is a commonly used antibacterial drug that can cause significant nephrotoxic effects in both humans and experimental animals. It has been reported that one mechanism of the toxic effects of aminoglycoside antibiotics are the result of oxidative reactions. The aim of this study is to examine the effects of N-acetylcysteine, a thiol-containing antioxidant, on renal function (serum creatinine) and morphology (renal tubular damage) in mice subjected to amikacin-induced nephrotoxicity. A total of 32 mice were equally divided into four groups that were injected with either saline, amikacin (1.2 g/kg intraperitoneally), N-acetylcysteine (150 mg/kg intraperitoneally for three days) plus amikacin (1.2 g/kg intraperitoneally on the third day as a single dose), or N-acetylcysteine (150 mg/kg intraperitoneally). Amikacin administration led to granulovacuolar tubular degeneration in light microscopic examination and myeloid bodies, mitochondrial electron-dense material deposition, and mitochondrial swelling in the proximal tubule epithelium in the electron microscopic evaluation. N-acetylcysteine administration before amikacin injection caused significant decreases in myeloid body and mitochondrial swelling and granulovacuolar tubular degeneration formation. Serum creatinine levels did not change as a result of any treatment. The results show that N-acetylcysteine has a protective effect on nephrotoxicity induced by amikacin. Higher doses of amikacin should be tried to observe biochemical effects.

Efficacy of the combination of N-acetylcysteine and desferrioxamine in the prevention and treatment of gentamicin-induced acute renal failure in male Wistar rats

BACKGROUND

Oxidative stress and the formation of aminoglycoside-iron complexes through iron-dependent Fenton reaction have been proposed to be the major mechanisms in the development of GM-induced acute renal failure (ARF); however, the efficacy of the combination of N-acetylcysteine (NAC) and desferrioxamine (DFX) in the prevention and the treatment of GM-induced ARF has not previously been investigated.

METHODS

In the prevention protocol, adult male Wistar rats received gentamicin (GM) [70 mg/kg, intraperitoneally (i.p), each 12 h for 7 days], NAC (20 mg/kg, sc, each 8 h for 7 days) and/or DFX (20 mg/kg, sc, at first, fourth and seventh days). In the treatment protocol animals received GM for 7 days. Additionally, animals received NAC and or DFX starting in the fourth day after GM administration. Parameters of renal function had been evaluated 24 h, 4 and 8 days after the beginning of GM administration in the prevention protocol and in Days 5 and 8 in the treatment protocol. At the end of experiment, lipid peroxidation (TBARS assay) and protein oxidation (protein carbonyls levels) formation were evaluated in kidney tissue as oxidative damage parameters.

RESULTS

In the prevention protocol, GM-induced ARF was prevented by the NAC and DFX association. Lipid peroxidation was attenuated by both antioxidant treatments, but the effects of NAC plus DFX were of greater magnitude. In the treatment protocol, plasma markers of renal injury were improved only in the NAC group, despite the similar antioxidant effect of both NAC, DFX and NAC plus DFX.

CONCLUSION

Although the combination of NAC and DFX was more effective in the prevention protocol, the use of NAC alone seemed to be superior to NAC-DFX combination, in the treatment of GM-induced ARF in adult male Wistar rats.

Effects of co-supplementation of vitamins E and C on gentamicin-induced nephrotoxicity in rat

Gentamicin (GM) is an effective antibiotic against severe gram-negative infections. However it can produce nephrotoxicity in human. Reactive oxygen species (ROS) have been proposed as the causative factors of the renal side effects the drug. This study was performed to investigate the protective role of antioxidant vitamins against GM-mediated nephropathy in an in situ model of isolated rat kidney. Male Sprague-Dawley rats were randomly assigned to one of the following groups of seven rats: group 1 (Control) was perfused with Tyrode solution; group 2 (GM), 200 microg ml(-1) GM was added to the perfusate; group 3 (GM + Vit C), as group 2 with vitamin C added to the drinking water for 3 days (200 mg l(-1)) and to the perfusate (100 mg l(-1)); group 4 (GM + Vit E), as group 2 with vitamin E (100 mg (100 g body weight)(-1), i.m.) injected 12 h before the start of the experiment; group 5 (GM + Vit C + Vit E) as group 2 with vitamin E and C co-administered (concentrations and conditions as in groups 3 and 4). To compare the groups, urinary lactate dehydrogenase (LDH), N-acetyle-beta-D-glucosaminidase (NAG) and alkaline phosphatase (ALP) activities, inulin clearance (glomerular filtration rate, GFR) and renal tissue glutathione (GSH) content were measured. GM caused a significant nephrotoxicity demonstrated by an increase in urinary LDH, NAG and ALP activities. Reduction in GSH content and a marked decrease in GFR were observed compared to controls. Vitamin C inhibited the GM-induced increase in urinary enzyme activities but did not show a significant effect on the GSH content or GFR. Vitamin E prevented the GM-induced reduction in GSH level without a significant improvement in GFR. Co-administration of vitamins C and E significantly prevented the GM-induced nephrotoxicity demonstrating by preservation of GFR and GSH levels and prevention of increase in urinary enzyme activities. We conclude that co-administration of moderate doses of vitamins C and E has beneficial effects on renal preservation in GM-induced nephrotoxicity.

Effect of silymarin and vitamin E on gentamicin-induced nephrotoxicity in dogs

Drug-induced nephrotoxicity is an important cause of renal failure in dogs. Aminoglycoside antibiotics, such as gentamicin, can produce nephrotoxicity in dogs, due to in part to an imbalance of pro- and antioxidants (oxidative stress). Silymarin (the mixture of flavonolignans extracted from Silybum marianum) has potentially beneficial antioxidant properties. A control group (saline, group 1, n = 5) was compared with dogs that were administrated gentamicin by intramuscular injection, at dosage of 20 mg/kg, once daily for 9 days (groups 2-5, n = 5 per group). The effects of vitamin E (group 3) and silymarin (group 4) alone and in combination (group 5) were compared for induced nephrotoxicity. Renal function was assessed using serum biochemical markers (creatinine and urea). Malondialdehyde (MDA) concentration were measured as a marker of lipid peroxidation. The activity of total serum antioxidants (TSAO) was assessed as a marker of antioxidant defences. Serum creatinine and urea concentrations were increased significantly and TSAO was decreased significantly in group 2 compared with group 1. Serum creatinine concentrations but not urea concentrations were significantly lower in groups 3 and 4 than in group 2 (P = 0.001). Serum MDA concentrations was significantly different between groups 2 and 3 (P = 0.01), 2 and 4 (P < 0.001) and 4 and 5 (P = 0.01). TSAO activity was significantly in group 4 (silymarin) than in group 2 (P = 0.002). Silymarin and vitamin E decreased gentamicin-induced nephrotoxicity in dogs.

Protective effects of caffeic acid phenethyl ester, vitamin C, vitamin E and N-acetylcysteine on vancomycin-induced nephrotoxicity in rats

The objective of this study was to compare the beneficial effects of caffeic acid phenethyl ester (CAPE), vitamin C, vitamin E and N-acetylcysteine on vancomycin-induced nephrotoxicity. Thirty rats were randomly devided into six groups: (i) control; (ii) vancomycin, 200 mg/kg administrated via intraperitoneal route; (iii) vancomycin plus CAPE-vancomycin with 10 micromol/kg CAPE; (iv) vancomycin plus vitamin C-vancomycin (intraperitoneally) with 200 mg/dl vitamin C in drinking water; (v) vancomycin plus vitamin E-vancomycin with 1000 mg/kg body weight vitamin E (intramuscularly); and (vi) vancomycin plus N-acetylcysteine-vancomycin with 10 mg/kg body weight (intraperitoneally) of N-acetylcysteine. Vancomycin treatments were started 1 day after the first administrations of these agents and continued for 7 days. At the end of the experiments, catalase activity was significantly decreased by vancomycin in kidney homogenates (P < 0.05). Vitamin E, vitamin C, N-acetylcysteine and CAPE administrations decreased the blood urea nitrogen levels increased by vancomycin, although significant differences were detected only in the vitamins E and C groups (P < 0.05). Increased renal malondialdehyde and nitric oxide levels by vancomycin were significantly suppressed by agents used in the study (P < 0.05). Histopathological examination demonstrated prominent damages in the vancomycin-treated group. Vitamin E was the most beneficial agent on vancomycin-induced tubular damage, followed by vitamin C, N-acetylcysteine and CAPE treatments, respectively. The data suggest that vitamin E, as well as vitamin C, N-acetylcysteine and CAPE, could be useful for reducing the detrimental effects on vancomycin-induced toxicity in kidneys.

Gentamicin-induced ototoxicity in hemodialysis patients is ameliorated by N-acetylcysteine

Aminoglycoside (AG) antibiotics are associated with several side effects, including a reversible nephrotoxicity and a permanent ototoxicity. Oxidative stress is thought to contribute to the pathophysiology of both conditions. We studied the possible protective effect of the antioxidant N-acetylcysteine (NAC) in gentamicin-induced hearing loss in hemodialysis patients. This study includes 53 hemodialysis patients scheduled to receive gentamicin for dialysis catheter-related bacteremia that were randomized to receive the antibiotic with or without NAC. Hearing function was assessed by the standard technique of pure-tone audiograms over a range of frequencies. Audiometric evaluations were performed at baseline, 1 week and at 6 weeks after the completion of gentamicin therapy. A total of 40 patients completed the study protocol with a mean duration of therapy of almost 15 days. At both 1 and 6 weeks after the completion of antibiotic therapy, there were significantly more patients exhibiting ototoxicity in the control group compared with the group receiving NAC. Additionally, significantly more patients in the control group had bilateral ototoxicity. The greatest otoprotective effect of NAC was noticed in the high audiometric tone frequencies. Taken together, our study suggests that NAC treatment may ameliorate gentamicin-induced ototoxicity in hemodialysis patients.

Oxidative stress pathways in the potentiation of noise-induced hearing loss by acrylonitrile

We hypothesize that the disruption of antioxidant defenses is a key mechanism whereby chemical contaminants can potentiate noise-induced hearing loss (NIHL). This hypothesis was tested using acrylonitrile (ACN), a widely used industrial chemical whose metabolism is associated with glutathione (GSH) depletion and cyanide (CN) generation. CN, in turn, can inhibit Cu/Zn superoxide dismutase (SOD). We have shown previously that ACN potentiates NIHL, even with noise exposure approaching permissible occupational levels. However, the relative involvement of GSH depletion and/or CN production in this potentiation is still unknown. In this study, we altered these metabolic pathways pharmacologically in order to further delineate the role of specific antioxidants in the protection of the cochlea. We investigated the effects of sodium thiosulfate (STS), a CN inhibitor, 4-methylpyrazole (4MP), a drug that blocks CN generation by competing with CYP2E1, and l-N-acetylcysteine (l-NAC), a pro-GSH drug, in order to distinguish between GSH depletion and CN production as the mechanism responsible for potentiation of NIHL by ACN. Long-Evans rats were exposed to an octave-band noise (97 dB SPL, 4h/day, 5 days) and ACN (50 mg/kg). Separate pre-treatments with STS (150 mg/kg), 4MP (100 mg/kg) and l-NAC (4 x 400 mg/kg) all dramatically reduced blood CN levels, but only l-NAC significantly protected GSH levels in both the liver and the cochlea. Concurrently, only l-NAC treatment decreased the auditory loss and hair cell loss resulting from ACN + noise, suggesting that GSH is involved in the protection of the cochlea against reactive oxygen species generated by moderate noise levels. On the other hand, CN does not seem to be involved in this potentiation.

Post-treatment with N-acetylcysteine ameliorates endotoxin shock-induced organ damage in conscious rats

N-acetylcysteine (NAC) is an antioxidant and cytoprotective agent with scavenging action against reactive oxygen species and inhibitory effects on pro-inflammatory cytokines. In a previous study, we found that pretreatment with NAC attenuated organ dysfunction and damage, reduced the production of free radicals, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) following endotoxemia elicited by administration of lipopolysaccharide (LPS). In the present study, we tested the effects of post-treatment with NAC on the sepsis-induced change. Post-treatment imitates clinical therapeutic regimen with administration of drug after endotoxemia. Endotoxin shock was induced by intravenous injection of Klebsiella pneumoniae LPS (10 mg/kg) in conscious rats. Mean arterial pressure (MAP) and heart rate (HR) were continuously monitored for 48 h after LPS administration. NAC was given 20 min after LPS. Measurements of biochemical substances were taken to reflect organ functions. Biochemical factors included blood urea nitrogen (BUN), creatinine (Cre), lactate dehydrogenase (LDH), creatine phosphokinase (CPK), aspartate transferase (GOT), alanine transferase (GPT), TNF-alpha, interleukin-6 (IL-6), and interleukin-10 (IL-10). LPS significantly increased blood BUN, Cre, LDH, CPK, GOT, GPT, TNF-alpha, IL-6, IL-10 levels and HR, and decreased MAP. Post-treatment with NAC diminished the decrease in MAP, increased the HR, and decreased the markers of organ injury (BUN, Cre, LDH, CPK, GOT, GPT) and inflammatory biomarkers (TNF-alpha, IL-6, IL-10) after LPS. We conclude that post-treatment with NAC suppresses the release of plasma TNF-alpha, IL-6, and IL-10 in endotoxin shock, and decreases the markers of organ injury. These beneficial effects protect against LPS-induced kidney, heart and liver damage in conscious rats. The beneficial effects may suggest a potential chemopreventive effect of this compound after sepsis.

Effects of N-acetylcysteine on radiocontrast nephropathy in rats

OBJECTIVE

N-acetylcysteine (NAC) has yielded some promising results recently in the prevention of radiocontrast nephropathy (RCN). In this study, the structural and functional effects of NAC on RCN were analyzed.

MATERIAL AND METHODS

Twenty-eight Wistar rats were randomized into four groups, as follows: Group 1, controls; Group 2, contrast; Group 3, contrast+NAC; and Group 4, NAC. All rats were deprived of water for 24 h and then contrast medium (ioxoglate; 10 ml/kg) was administered to Groups 2 and 3. NAC (50 mg/kg) was introduced enterally to Groups 3 and 4 at a dose of 50 mg/kg in 0.5 ml of distilled water, in four sequential doses 12h apart, starting after 12?h of water deprivation. After 4 days, rats were sacrificed. Creatinine clearance was calculated. The malondialdehyde (MDA) level was quantified in tissue samples. Slides stained with hematoxylin-eosin and periodic acid-Schiff were examined by means of light microscopy. Each tubular cross-section from all images was scored as either mild (preserved brush border, no necrosis), moderate (loss of brush border, no necrosis) or severe (loss of brush border accompanied by necrosis) and the frequencies of these lesion severities were compared.

RESULTS

Mean baseline serum creatinine levels and creatinine clearances were similar in all groups. Mean serum creatinine level increased significantly only in Group 2 (0.6+/-0.1 vs 0.7+/-0.2 mg/dl; p<0.05). Tissue MDA levels were similar in all groups. Moderate (13.8%+/-1.5% vs 42%+/-1.4%; p<0.05) and severe (0% vs 40%+/-2.1%; p<0.05) lesions were significantly more frequent in Group 2 compared to Group 1. The frequency of severe lesions in Group 3 was found to be halved compared to that in Group 1 (40%+/-2.1% vs 20.2%+/-0.86%; p<0.05).

CONCLUSION

NAC protects the kidneys following exposure to contrast medium as it decreased the severity of tubular lesions in rats.

Biomarker discovery by imaging mass spectrometry: transthyretin is a biomarker for gentamicin-induced nephrotoxicity in rat

Adverse drug effects are often associated with pathological changes in tissue. An accurate depiction of the undesired affected area, possibly supported by mechanistic data, is important to classify the effects with regard to relevance for human patients. MALDI imaging MS represents a new analytical tool to directly provide the spatial distribution and the relative abundance of proteins in tissue. Here we evaluate this technique to investigate potential toxicity biomarkers in kidneys of rats that were administered gentamicin, a well known nephrotoxicant. Differential analysis of the mass spectrum profiles revealed a spectral feature at 12,959 Da that strongly correlates with histopathology alterations of the kidney. We unambiguously identified this spectral feature as transthyretin (Ser(28)-Gln(146)) using an innovative combination of tissue microextraction and fractionation by reverse-phase liquid chromatography followed by a top-down tandem mass spectrometric approach. Our findings clearly demonstrate the emerging role of imaging MS in the discovery of toxicity biomarkers and in obtaining mechanistic insights concerning toxicity mechanisms.

Comparison of N-acetylcysteine and fenoldopam for preventing contrast-induced nephropathy (CAFCIN)

BACKGROUND

N-acetylcysteine and fenoldopam are commonly prescribed for prevention of contrast mediated nephropathy, however, comparative superiority of either agent is unknown.

METHODS

In a prospective, randomized, parallel-group trial, adult cardiac catheterization patients at the university and veterans' hospitals with pre-existing stable renal insufficiency were randomized to N-acetylcysteine 600 mg orally twice daily for 4 doses or fenoldopam 0.1 mcg/kg/min intravenously for a minimum of 8 h. All patients received intravenous hydration with normal saline (5% dextrose in normal saline for diabetics on insulin). Randomization was stratified for diabetes. The primary endpoint was mean change in Scr at 72 h. Secondary endpoint was the incidence of contrast-induced nephropathy (25% increase above baseline Scr or absolute increase of 0.5 mg/dL).

RESULTS

Study termination occurred after ninety-five patients (mean age 68+/-10 years, female 25%, diabetic 42%, mean baseline Scr 1.5+/-0.4 mg/dL) were randomized, with 84 completing follow-up (44 N-acetylcysteine, 40 fenoldopam). Overall, there were no significant differences in mean change in Scr at 72 h (N-acetylcysteine 0.20+/-0.72 vs. fenoldopam 0.08+/-0.48 mg/dL, p=0.4) or incidence of contrast-induced nephropathy (N-acetylcysteine 5 vs fenoldopam 8, p=0.4). No differences were detected in subgroup analyses for diabetes, baseline Scr >1.7 or 2.0 mg/dL, gender, age >70 years, or contrast volume >150 mL. Results were similar after multivariate adjustment for diabetes, contrast volume, heart failure and gender.

CONCLUSIONS

Our randomized comparison failed to demonstrate a significant difference in the abilities of N-acetylcysteine and fenoldopam to prevent the decline in renal function or the incidence of contrast-induced nephropathy during cardiac catheterization.

Effect of Spirulina, a blue green algae, on gentamicin-induced oxidative stress and renal dysfunction in rats

Gentamicin (GM), an aminoglycoside, is widely employed in clinical practice for the treatment of serious Gram-negative infections. The clinical utility of GM is limited by the frequent incidence of acute renal failure. Experimental evidences suggest that oxidative and nitrosative stress play an important role in GM nephrotoxicity. Spirulina fusiformis is a blue green algae with potent free radical scavenging properties. The present study was designed to investigate renoprotective potential of S. fusiformis, against GM-induced oxidative stress and renal dysfunction. Spirulina fusiformis (500, 1000, 1500 mg/kg, p.o.) was administered 2 days before and 8 days concurrently with GM (100 mg/kg, i.p.). Renal injury was assessed by measuring serum creatinine, blood urea nitrogen and creatinine clearance and serum nitrite levels. Renal oxidative stress was determined by renal malondialdehyde levels, reduced glutathione levels and by enzymatic activity of superoxide dismutase (SOD) and catalase. Chronic GM administration resulted in marked renal oxidative and nitrosative stress and significantly deranged renal functions. Treatment with S. fusiformis significantly and dose-dependently restored renal functions, reduced lipid peroxidation and enhanced reduced glutathione levels, SOD and catalase activities. The results of present study clearly demonstrate the pivotal role of reactive oxygen species and their relation to renal dysfunction and point to the therapeutic potential of S. fusiformis in GM-induced nephrotoxicity.