Protective Effects of Vitamin C on Cisplatin-Induced Renal Damage: A Light and Electron Microscopic Study

Vitamin C Deficiency Causes Cell Type-Specific Epigenetic Reprogramming and Acute Tubular Necrosis in a Mouse Model

BACKGROUND

Vitamin C deficiency is found in patients with variable kidney diseases. However, the role of vitamin C as an epigenetic regulator in renal homeostasis and pathogenesis remains largely unknown.

METHODS

We showed that vitamin C deficiency leads to acute tubular necrosis (ATN) using a vitamin C-deficient mouse model (Gulo knock-out). DNA/RNA epigenetic modifications and injured S3 proximal tubule cells were identified in the vitamin C-deficient kidneys using whole-genome bisulfite sequencing, methylated RNA immunoprecipitation sequencing, and single-cell RNA sequencing.

RESULTS

Integrated evidence suggested that epigenetic modifications affected the proximal tubule cells and fenestrated endothelial cells, leading to tubule injury and hypoxia through transcriptional regulation. Strikingly, loss of DNA hydroxymethylation and DNA hypermethylation in vitamin C-deficient kidneys preceded the histologic sign of tubule necrosis, indicating the causality of vitamin C-induced epigenetic modification in ATN. Consistently, prophylactic supplementation of an oxidation-resistant vitamin C derivative, ascorbyl phosphate magnesium, promoted DNA demethylation and prevented the progression of cisplatin-induced ATN.

CONCLUSIONS

Vitamin C played a critical role in renal homeostasis and pathogenesis in a mouse model, suggesting vitamin supplementation may be an approach to lower the risk of kidney injury.

Pharmacological Effects of Cisplatin Combination with Natural Products in Cancer Chemotherapy

Cisplatin and other platinum-based drugs, such as carboplatin, ormaplatin, and oxaliplatin, have been widely used to treat a multitude of human cancers. However, a considerable proportion of patients often relapse due to drug resistance and/or toxicity to multiple organs including the liver, kidneys, gastrointestinal tract, and the cardiovascular, hematologic, and nervous systems. In this study, we sought to provide a comprehensive review of the current state of the science highlighting the use of cisplatin in cancer therapy, with a special emphasis on its molecular mechanisms of action, and treatment modalities including the combination therapy with natural products. Hence, we searched the literature using various scientific databases., such as MEDLINE, PubMed, Google Scholar, and relevant sources, to collect and review relevant publications on cisplatin, natural products, combination therapy, uses in cancer treatment, modes of action, and therapeutic strategies. Our search results revealed that new strategic approaches for cancer treatment, including the combination therapy of cisplatin and natural products, have been evaluated with some degree of success. Scientific evidence from both in vitro and in vivo studies demonstrates that many medicinal plants contain bioactive compounds that are promising candidates for the treatment of human diseases, and therefore represent an excellent source for drug discovery. In preclinical studies, it has been demonstrated that natural products not only enhance the therapeutic activity of cisplatin but also attenuate its chemotherapy-induced toxicity. Many experimental studies have also reported that natural products exert their therapeutic action by triggering apoptosis through modulation of mitogen-activated protein kinase (MAPK) and p53 signal transduction pathways and enhancement of cisplatin chemosensitivity. Furthermore, natural products protect against cisplatin-induced organ toxicity by modulating several gene transcription factors and inducing cell death through apoptosis and/or necrosis. In addition, formulations of cisplatin with polymeric, lipid, inorganic, and carbon-based nano-drug delivery systems have been found to delay drug release, prolong half-life, and reduce systemic toxicity while other formulations, such as nanocapsules, nanogels, and hydrogels, have been reported to enhance cell penetration, target cancer cells, and inhibit tumor progression.

Increase in Protective Effect of Panax vietnamensis by Heat Processing on Cisplatin-Induced Kidney Cell Toxicity

Cisplatin is a platinum-based anticancer agent used for treating a wide range of solid cancers. One of the side effects of this drug is its severe nephrotoxicity, limiting the safe dose of cisplatin. Therefore, many natural products have been studied and applied to attenuate the toxicity of this compound. In this study, we found that steamed Vietnamese ginseng (Panax vietnamensis) could significantly reduce the kidney damage of cisplatin in an in vitro model using porcine proximal tubular LLC-PK1 kidney cells. From processed ginseng under optimized conditions (120 °C, 12 h), we isolated seven compounds (20(R,S)-ginsenoside Rh2, 20(R,S)-ginsenoside Rg3, ginsenoside Rk1, ginsenoside-Rg5, and ocotillol genin) that showed kidney-protective potential against cisplatin toxicity. By comparing the 50% recovery concentration (RC₅₀), the R form of ginsenoside, Rh2 and Rg3, had RC₅₀ values of 6.67 ± 0.42 µM and 8.39 ± 0.3 µM, respectively, while the S forms of ginsenoside, Rh2 and Rg3, and Rk1, had weaker protective effects, with RC₅₀ ranging from 46.15 to 88.4 µM. G-Rg5 and ocotillol, the typical saponin of Vietnamese ginseng, had the highest RC₅₀ (180.83 ± 33.27; 226.19 ± 66.16, respectively). Our results suggest that processed Vietnamese gingseng (PVG), as well as those compounds, has the potential to improve kidney damage due to cisplatin toxicity.

Synergistic Effect of Vitamin C with Cisplatin for Inhibiting Proliferation of Gastric Cancer Cells

Background:

Ascorbic acid, known as vitamin C, has been used in combination with a number of cytotoxic agents in vitro and in vivo with contradictory results on its effectiveness. It is believed that vitamin C can sensitize different cancer cells to common therapy strategies such as chemotherapy and radiotherapy. During current research, the combination effect of vitamin C with cisplatin was evaluated against gastric cancer cells.

Methods:

MTT-based proliferation assay, CI method, and flow cytometry technique were employed for the assessment of cell cycle and determination of apoptosis/necrosis on the AGS cell line.

Results:

Co-treatment of gastric cancer cells with vitamin C in its IC₅₀ dose in addition to cisplatin in both IC₅₀ (10 µg/ml) and five times less (2 µg/ml) doses could increase the cytotoxicity effect of cisplatin in a synergistic manner. Moreover, the pointed co-treatment approach could induce the cell count in sub-G0 phase while reducing it in the G0/G1, G2/M, and S phases. Further findings showed that the combined dose of vitamin C and cisplatin could increase the percentage of apoptotic and necrotic cells in comparison with a single dose of cisplatin.

Conclusion:

This study introduces a possible approach for the treatment of gastric cancer with more potency and less amount of administered cisplatin to induce toxicity.

Nephroprotective effect of Rudgea viburnoides (Cham.) Benth leaves on gentamicin-induced nephrotoxicity in rats

RELEVANCE

Rudgea viburnoides, popularly known as "congonha-de-bugre" or "erva de bugre", is used in folk medicine as hypotensive, blood depurative, anti-rheumatic, diuretic and in the treatment of kidney and bladder pain.

AIM

Based on the popularly acclaimed nephron-protective effect of R. viburnoides, we investigated, using rats, the protective effect of this plant extract on gentamicin-induced kidney injury.

MATERIAL AND METHODS

Urinary volume, water and food intakes were assessed in adult male Wistar rats (naive or gentamicin-induced model of nephrotoxicity) treated with R. viburnoides extract. Also blood and kidney samples were collected for further laboratory and histological analyses.

RESULTS

R. viburnoides leaves extract improved renal function. It also improved the renal function impairments caused by gentamicin-induced nephrotoxicity, as revealed by glomerular filtration rate, urine output and proteinuria.

CONCLUSION

R. viburnoides exert renoprotective effect, which may support its popular use for renal diseases treatment.

An integrative view of cisplatin-induced renal and cardiac toxicities: Molecular mechanisms, current treatment challenges and potential protective measures

Cisplatin is currently one of the most widely-used chemotherapeutic agents against various malignancies. Its clinical application is limited, however, by inherent renal and cardiac toxicities and other side effects, of which the underlying mechanisms are only partly understood. Experimental studies show cisplatin generates reactive oxygen species, which impair the cell's antioxidant defense system, causing oxidative stress and potentiating injury, thereby culminating in kidney and heart failure. Understanding the molecular mechanisms of cisplatin-induced renal and cardiac toxicities may allow clinicians to prevent or treat this problem better and may also provide a model for investigating drug-induced organ toxicity in general. This review discusses some of the major molecular mechanisms of cisplatin-induced renal and cardiac toxicities including disruption of ionic homeostasis and energy status of the cell leading to cell injury and cell death. We highlight clinical manifestations of both toxicities as well as (novel)biomarkers such as kidney injury molecule-1 (KIM-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). We also present some current treatment challenges and propose potential protective strategies including combination therapy with novel pharmacological compounds that might mitigate or prevent these toxicities, which include the use of hydrogen sulfide.

Nephroprotective effect of estrogen and progesterone combination on cisplatin-induced nephrotoxicity in ovariectomized female rats

Recently, we reported that estrogen (Es) has no beneficial effect on cisplatin (CP)-induced nephrotoxicity, but the role of progesterone (Pr) and the combination of Es and Pr are not yet well-defined. In this study, we investigated the protective role of Pr, and co-administration of Es/Pr on CP-induced nephrotoxicity. Eighty-six ovariectomized female Wistar rats were divided into 13 groups, and the experiments were performed in two phases. In Phase I, Groups 1-4 received 2, 5, 10, and 25 mg/kg, IM Pr dissolved in sesame oil every 5 days for four doses. Groups 5-8 had the same treatment regimen as Groups 1-4, but after the third injection the animals also received continuous dose of CP (2.5 mg/kg/day, i.p.) for 8 days. Group 9, as the positive control group, received sesame oil instead of Pr plus CP. Group 10, as the negative control group, received sesame oil instead of Pr. After the most effective dose of Pr was determined in Phase I, Groups 11-13 in Phase II received 10 mg/kg Pr plus either 0.25, 0.5, or 1 mg/kg, IM estradiol valerate every 5 days for four doses. After the third injection, they also received a continuous dose of CP for 8 days. The levels of blood urea nitrogen (BUN) and creatinine (Cr), kidney tissue damage score (KTDS), and kidney weight (KW) increased and body weight (BW) decreased in the positive control group (P < 0.05). Administration of Pr (10 mg/kg) plus CP decreased KTDS and BW loss and KW. Co-administration of ES/Pr at specific doses improved Cr, BUN, and KTDS; and resulted in reduced CP-induced nephrotoxicity. The results obtained suggest that the beneficial effect of Pr on CP-induced nephrotoxicity is dose-dependent. In addition, combination of Es/Pr with a specific dose decreased CP-induced nephrotoxicity.

Riboflavin Arrests Cisplatin-Induced Neurotoxicity by Ameliorating Cellular Damage in Dorsal Root Ganglion Cells

Cis-Diamminedichloroplatinum II- (CP-) induced neurotoxicity is one of the least explored aspects of this drug. Dorsal root ganglia (DRG) cells are considered as the primary target, and their damage plays a vital role in pathogenesis and etiology of CP-induced neurotoxicity. The present study is aimed at confirming if riboflavin (RF) has any protective role in shielding the DRG from CP-induced toxicity. After conducting the established treatment strategy on mice under photoillumination, it was observed that, despite the fact that RF alone is partially toxic, its combination with CP significantly ameliorated the drug-induced damage in DRG cells as evidenced by histological analysis. In addition, it was interesting to observe that the combination group (RF + CP) was able to induce apoptosis in the target cells up to a significant extent which is considered as the most preferred way of countering cancer cells. Therefore, RF can act as an effective adjuvant compound in CP-based chemoradiotherapy to improve clinical outcomes in the contemporary anticancer treatment regimes.

Icodextrin reduces insulin resistance in non-diabetic patients undergoing automated peritoneal dialysis: results of a randomized controlled trial (STARCH)

BACKGROUND

Insulin resistance is a common risk factor in chronic kidney disease patients contributing to the high cardiovascular burden, even in the absence of diabetes. Glucose-based peritoneal dialysis (PD) solutions are thought to intensify insulin resistance due to the continuous glucose absorption from the peritoneal cavity. The aim of our study was to analyse the effect of the substitution of glucose for icodextrin on insulin resistance in non-diabetic PD patients in a multicentric randomized clinical trial.

METHODS

This was a multicenter, open-label study with balanced randomization (1:1) and two parallel-groups. Inclusion criteria were non-diabetic adult patients on automated peritoneal dialysis (APD) for at least 3 months on therapy prior to randomization. Patients assigned to the intervention group were treated with 2L of icodextrin 7.5%, and the control group with glucose 2.5% during the long dwell and, at night in the cycler, with a prescription of standard glucose-based PD solution only in both groups. The primary end-point was the change in insulin resistance measured by homeostatic model assessment (HOMA) index at 90 days.

RESULTS

Sixty patients were included in the intervention (n = 33) or the control (n = 27) groups. There was no difference between groups at baseline. After adjustment for pre-intervention HOMA index levels, the group treated with icodextrin had the lower post-intervention levels at 90 days in both intention to treat [1.49 (95% CI: 1.23-1.74) versus 1.89 (95% CI: 1.62-2.17)], (F = 4.643, P = 0.03, partial η(2) = 0.078); and the treated analysis [1.47 (95% CI: 1.01-1.84) versus 2.18 (95% CI: 1.81-2.55)], (F = 7.488, P = 0.01, partial η(2) = 0.195).

CONCLUSIONS

The substitution of glucose for icodextrin for the long dwell improved insulin resistance measured by HOMA index in non-diabetic APD patients.

Angiotensin Type-1 Receptor Blockade May Not Protect Kidney against Cisplatin-Induced Nephrotoxicity in Rats

Background. Cisplatin (CDDP) is an anticancer drug, which is accompanied with major side effects including nephrotoxicity. We tested two doses of losartan (10 and 20 mg/kg/day) against nephrotoxicity in a rat model treated with daily administration of CDDP (2.5 mg/kg/day). Methods. Five groups of rats were examined. Groups 1 and 2 received losartan 10 and 20 mg/kg/day, i.p, for a period of 10 days. Group 3 received saline for 10 days, but from day 3 the animals received CDDP (2.5 mg/kg/day, i.p) for the next seven days. Groups 4 and 5 received treatment regimen the same as groups 1 and 2, but from day 3 they also received CDDP for the next seven days. At the end of the experiment, blood samples were obtained and the kidneys were removed to undergo pathological investigation and to obtain supernatant from homogenized tissue. Results. CDDP induced nephrotoxicity, but the serum levels of creatinine and blood urea nitrogen were not attenuated by losartan. The pathological findings confirmed that losartan did not have nephroprotective effect in this experimental model. Conclusion. According to the findings, losartan could not improve renal function impaired by toxicity induced by continuous doses of CDDP, and also it worsened the renal failure.

The potential role of Azadirachta indica treatment on cisplatin-induced hepatotoxicity and oxidative stress in female rats

Azadirachta indica A. Juss. (neem, family: Meliaceae) is perhaps the most commonly used traditional medicinal plant of India. In this study we investigated the protective effect of methanolic neem leaves extract (MNLE; 500 mg/Kg bwt) on rats treated with cisplatin (CDDP)-induced hepatotoxicity. Adult rats were randomly divided into four groups. CDDP was given to rats by intraperitoneal injection, while MNLE was given by oral gavage for 5 days after the CDDP injection. The injury and oxidative stress caused by CDDP on the liver and the effect of MNLE were evaluated by measuring (a) histological changes, (b) tissue biochemical oxidant and antioxidant parameters, and (c) investigating apoptosis markers immunohistochemically and by real time PCR. After treatment with MNLE, the histological damage and apoptosis induction caused by cisplatin were improved. Malondialdehyde and nitric oxide were significantly decreased; the antioxidant system, namely, glutathione content, glutathione-S-transferase, glutathione peroxidase, catalase, and superoxide dismutase activities were significantly elevated. In conclusion, MNLE may have a potential role when combined with cisplatin in chemotherapy to alleviate cisplatin-induced damage and oxidative stress in liver.

Effects of Fennel Essential Oil on Cisplatin-induced Nephrotoxicity in Ovariectomized Rats

Background:

Cisplatin (cis-diamminedichloroplatinum II (CDDP)) is an effective drug in cancer therapy to treat solid tumors. However, the drug is accompanied by nephrotoxicity. Previous reports indicated that estrogen has no protective role against CDDP-induced nephrotoxicity, but the role of phytoestrogen as an estrogenic agent in plants is not determined yet. The major composition of fennel essential oil (FEO) is trans-anethole that has estrogenic activity; so, we used FEO as a phytoestrogen source against CDDP-induced nephrotoxicity.

Materials and Methods:

Fifty-four ovariectomized Wistar rats were divided into seven groups. Groups 1-3 received different doses of FEO (250, 500, and 1000 mg/kg/day, respectively) for 10 days. Group 4 received saline for 10 days plus single dose of CDDP (7 mg/kg, intraperitoneally (ip)) at day 3. Groups 5-7 received FEO similar to groups 1-3, respectively; plus a single dose of CDDP (7 mg/kg, ip) on day 3. On day 10, the animals were sacrificed for histopathological studies.

Results:

The serum levels of blood urea nitrogen (BUN) and creatinine (Cr), kidney tissue damage score (KTDS), and kidney weight (KW) and body weight changes in CDDP-treated groups increased significantly (P < 0.05). FEO did not reduce the levels of BUN and Cr, KTDS, and KW and body weight changes. Also, the serum and tissue levels of nitrite were not altered significantly by FEO.

Conclusion:

FEO, as a source of phytoestrogen, did not induce kidney damage. In addition, FEO similar to estrogen was not a nephroprotectant agent against CDDP-induced nephrotoxicity.

Cisplatin : an old drug with a newfound efficacy -- from mechanisms of action to cytotoxicity

INTRODUCTION

Cisplatin is a highly effective antineoplastic drug with an extremely current mechanism of action. Cisplatin-induced side effects are dose-dependent and limit the administration of increased dosages, thus compromising its therapeutic efficacy.

AREAS COVERED

This review aims to describe the emerging knowledge about the biochemical mechanisms that mediate cisplatin cytotoxicity and side effects. A specific section is devoted to discuss the pathogenesis of cisplatin-related toxicities and the potential measures to counteract them.

EXPERT OPINION

Although cisplatin has been used for a long time, only recently its exact mechanism of action has been better defined. The cytotoxic activity of cisplatin is largely dependent on the glycolytic metabolism of tumor cells: cisplatin redirects cancer cells to oxidative phosphorylation from the 'Warburg effect', which is considered one of the most important mechanisms of tumor cell survival. The interference of cisplatin with glucose metabolism is also a cause of its relevant toxicities. The emerging knowledge on the complex mechanisms, which mediate cisplatin cytotoxicity and side effect, may lead to a more appropriate and safe use of this drug. Further studies are warranted to define and implement its effectiveness in combination with targeted drugs able to interfere with cellular energy metabolism, such as mTOR inhibitors.

Protective effect of CV247 against cisplatin nephrotoxicity in rats

CV247 (CV), an aqueous mixture of copper (Cu) and manganese (Mn) gluconates, vitamin C and sodium salicylate increased the antitumour effects of cisplatin (CDPP; cis-diamminedichloroplatinum) in vitro. We hypothesized that the antioxidant and cyclooxygenase-2 (COX-2; prostaglandin-endoperoxide synthase 2) inhibitory components of CV can protect the kidneys from CDPP nephrotoxicity in rats. CDPP (6.5 mg/kg, intraperitoneally) slightly elevated serum creatinine (Crea) and blood urea nitrogen (BUN) 12 days after treatment. Kidney histology demonstrated extensive tubular epithelial damage and COX-2 immunoreactivity increased 14 days after treatment. A large amount of platinum (Pt) accumulated in the kidney of CDPP-treated rats. Furthermore, CDPP decreased renal iron (Fe), molybdenum (Mo), zinc (Zn), Cu and Mn concentrations and increased plasma Fe and Cu concentrations. CDPP elevated plasma free radical concentration. Treatment with CV alone for 14 days (twice 3 ml/kg/day orally) did not influence these parameters. Chronic CV administration after CDPP reduced renal histological damage and slightly decreased COX-2 immunoreactivity, while failed to prevent the increase in Crea and BUN levels. Blood free radical concentration was reduced, that is, CV improved redox homeostasis. CV restored plasma Fe and renal Fe, Mo and Zn, while decreased Pt and elevated Cu and Mn concentrations in the kidney. Besides the known synergistic antitumour effects with CDPP, CV partially protected the kidneys from CDPP nephrotoxicity probably through its antioxidant effect.

Cisplatin-induced neurotoxicity in vivo can be alleviated by riboflavin under photoillumination

Cisplatin (CP)-induced neurotoxicity is one of the major clinical problems in CP-based chemoradiotherapy, leading to its discontinuation depending upon their severity. In the present investigation, the photosensitizing property of riboflavin (RF) has been used to ameliorate the CP-induced neurotoxicity. According to dosing plan, the healthy mice were given RF, CP, and their combinations under photoillumination with their controls without any light exposure. After the treatment, antioxidant enzymes, cellular reductants, glutathione-S-transferase, brain markers, and oxidation products were assessed besides histopathology in their brain samples. These parameters revealed that RF ameliorates CP-induced neurotoxicity in a dose-dependent manner under photoillumination. Hence, inclusion of RF in CP-based chemoradiotherapy can be an effective strategy to counter CP-induced neurotoxicity.

Cisplatin-induced nephrotoxicity and targets of nephroprotection: an update

Cisplatin is a highly effective antitumor agent whose clinical application is limited by the inherent nephrotoxicity. The current measures of nephroprotection used in patients receiving cisplatin are not satisfactory, and studies have focused on the investigation of new possible protective strategies. Many pathways involved in cisplatin nephrotoxicity have been delineated and proposed as targets for nephroprotection, and many new potentially protective agents have been reported. The multiple pathways which lead to renal damage and renal cell death have points of convergence and share some common modulators. The most frequent event among all the described pathways is the oxidative stress that acts as both a trigger and a result. The most exploited pathways, the proposed protective strategies, the achievements obtained so far as well as conflicting data are summarized and discussed in this review, providing a general view of the knowledge accumulated with past and recent research on this subject.

Carvedilol protects against apoptotic cell death induced by cisplatin in renal tubular epithelial cells

Cisplatin is a highly effective chemotherapeutic drug; however, its use is limited by nephrotoxicity. Studies showed that the renal injury produced by cisplatin involves oxidative stress and cell death mediated by apoptosis and necrosis in proximal tubular cells. The use of antioxidants to decrease cisplatin-induced renal cell death was suggested as a potential therapeutic measure. In this study the possible protective effects of carvedilol, a beta blocker with antioxidant activity, was examined against cisplatin-induced apoptosis in HK-2 human kidney proximal tubular cells. The mitochondrial events involved in this protection were also investigated. Four groups were used: controls (C), cisplatin alone at 25 μM (CIS), cisplatin 25 μM plus carvedilol 50 μM (CV + CIS), and carvedilol alone 50 μM (CV). Cell viability, apoptosis, caspase-9, and caspase-3 were determined. Data demonstrated that carvedilol effectively increased cell viability and minimized caspase activation and apoptosis in HK-2 cells, indicating this may be a promising drug to reduce nephrotoxicity induced by cisplatin.

Pomegranate seed extract attenuates chemotherapy-induced acute nephrotoxicity and hepatotoxicity in rats

Cisplatin (CDDP), one of the most active cytotoxic agents against cancer, has adverse side effects, such as nephrotoxicity and hepatotoxicity. The present study was designed to investigate the potential protective effect of pomegranate seed extract (PSE) against oxidative stress caused by CDDP injury of the kidneys and liver by measuring tissue biochemical and antioxidant variables and immunohistochemically testing caspase-3-positive cells. Twenty-four Sprague-Dawley rats were divided into 4 groups: control; CDDP: injected intraperitoneally with CDDP (7 mg/kg body weight, single dose); PSE: treated for 15 consecutive days by gavage with PSE (300 mg/kg per day); and PSE+CDDP: treated by gavage with PSE 15 days after a single injection of CDDP. The degree of protection against CDDP injury afforded by PSE was evaluated by determining the levels of malondialdehyde as a measure of lipid peroxidation. The levels of glutathione and activities of glutathione peroxidase, glutathione S-transferase, and superoxide dismutase were estimated from liver and kidney homogenates; the liver and kidney were also histologically examined. PSE elicited a significant protective effect toward liver and kidney by decreasing the level of lipid peroxidation; elevating the levels of glutathione S-transferase; and increasing the activities of glutathione peroxidase, glutathione S-transferase, and superoxide dismutase. These biochemical observations were supported by immunohistochemical findings and suggested that PSE significantly attenuated nephrotoxicity and hepatotoxicity by the way of its antioxidant, radical-scavenging, and antiapoptotic effects. This PSE extract could be used as a dietary supplement in patients receiving chemotherapy medications.

Ameliorative effect of riboflavin on the cisplatin induced nephrotoxicity and hepatotoxicity under photoillumination

Cisplatin is a widely used anticancer drug. It is documented that it elicits major side effects like nephrotoxicity and hepatotoxicity due to oxidative stress forcing the patients to limit its clinical use in long term treatment. Riboflavin (vitamin B(2)) is a strong photosensitizer because it generates reactive oxygen species (ROS) upon photoillumination. We have tried to trap its photosensitizing property to ameliorate the cisplatin induced nephrotoxicity and hepatotoxicity in mice. They were treated with riboflavin and cisplatin separately as well as with their combination under photoilluminated condition. The status of major antioxidant enzymes, antioxidant proteins, functional markers, lipid peroxidation and protein oxidation was studied in liver, kidneys and serum samples of all the groups. Cisplatin treated group showed significantly compromised level of antioxidant enzymes and the proteins with higher extent of lipid and protein oxidation. Similar but less pronounced pattern was observed in the riboflavin treated group. The groups treated with the combination of cisplatin and riboflavin showed all the parameters tended towards normal levels in a dose dependent manner. Hence, it can be hypothesized that riboflavin shows ameliorative effect on the cisplatin induced nephrotoxicity and hepatotoxicity under the mentioned treatment conditions.

Carvedilol protects against the renal mitochondrial toxicity induced by cisplatin in rats

The clinical use of cisplatin is highly limited by its nephrotoxicity, which has been associated with mitochondrial dysfunction. We investigated the protective effect of carvedilol, an antihypertensive with strong antioxidant properties, against the nephrotoxicity induced by cisplatin in rats. Carvedilol was able to counteract the renal damage by preventing the mitochondrial dysfunction induced by cisplatin. The mitochondrial eletrochemical potential, calcium uptake, respiration and the phosphorylative capacity were preserved by the co-administration of carvedilol. The mechanism of protection probably does not involve alterations in the cellular and sub-cellular distribution of cisplatin. The study suggests that carvedilol is a potential drug for the adjuvant nephroprotective therapy during cisplatin chemotherapy.

Protective effect of L-carnitine against cisplatin-induced liver and kidney oxidant injury in rats

The present study was designed to investigate the protective effects of L-carnitine (LC) on changes in the levels of lipid peroxidation and endogenous antioxidants induced by cisplatin (cis-diamminedichloroplatinum II, CDDP) in the liver and kidney tissues of rats. Twenty-four Sprague Dawley rats were equally divided into four groups of six rats each: control, cisplatin, L-carnitine, and L-carnitine plus cisplatin. The degree of protection produced by L-carnitine was evaluated by determining the level of malondialdehyde (MDA). The activity of glutathione (GSH), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST), and superoxide dismutase (SOD) were estimated from liver and kidney homogenates, and the liver and kidney were histologically examined as well. L-carnitine elicited significant liver and kidney protective activity by decreasing the level of lipid peroxidation (MDA) and elevating the activity of GSH, GSHPx, GST, and SOD. Furthermore, these biochemical observations were supported by histological findings. In conclusion, the present study indicates a significant role for reactive oxygen species (ROS) and their relation to liver and kidney dysfunction, and points to the therapeutic potential of LC in CDDP-induced liver and kidney toxicity.

Pediatric myocardial stunning underscores the cardiac toxicity of conventional hemodialysis treatments

BACKGROUND AND OBJECTIVE

In adults, hemodialysis (HD)-induced ischemia causes reversible myocardial dysfunction (myocardial stunning) that is progressive with raised attendant mortality. Children share an increased risk for death from a spectrum of uremia-related cardiovascular abnormalities but in the absence of significant classical atheromatous coronary artery disease; therefore, we elected to assess children who were on HD for the occurrence of myocardial stunning to investigate the relative importance of characteristic uremic cardiovascular abnormalities in the development of ischemic cardiac injury.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We included all single-center long-term HD patients (n = 12; range 2 to 17 yr), excluding those with structural cardiac disease. Patients underwent conventional thrice-weekly HD for 4 h using high-flux membranes. We measured regional left ventricle wall motion using serial echocardiography (before HD, during HD, and 15 min after HD). Significant stunning was defined as a 20% reduction in regional wall motion (RRWM) in two or more segments and hyperkinesis as an either >20 or >50% increase in shortening fraction (SF).

RESULTS

Eleven of 12 patients developed myocardial stunning with varying degrees of compensatory hyperkinesis in unaffected segments, maintaining left ventricular ejection fraction throughout HD. The mean segmental %SF([Overall]) and %SF([RRWM]) fell during HD (2.19 to 1.77 and 2.72 to 1.37, respectively). Intradialytic BP reduction was significantly associated with mean segmental %SF([RRWM]).

CONCLUSIONS

Children who receive conventional HD experience myocardial stunning. These data, in combination with previous adult studies of intradialytic myocardial blood flow, suggest a characteristic cardiovascular phenotype in HD patients that predisposes to significant demand ischemia.

Vitamin C protects against ionizing radiation damage to goblet cells of the ileum in rats

The aim of the present study was to evaluate the radioprotective effect of vitamin C on gamma-radiation-induced damage to goblet cells of the ileum. Thirty male Wistar albino rats weighing between 250 and 300 g were randomized into the following study groups: I, control; II, single dose radiation treated; III, two dose radiation treated with a 4-day interval between doses; IV, single dose radiation treated with vitamin C; V, two dose radiation treated with vitamin C. Each group contained six animals. The rats in groups IV and V were given a daily dose of 100 mg/kg of vitamin C for 14 and 18 days, respectively. During the vitamin C administration period, the rats in group IV were exposed in the abdominal area to a gamma-ray dose of 5 Gy on day 10 and group V was exposed to same dose of radiation on days 10 and 14. Irradiation and treatment groups were decapitated 4 days after exposure to single or two dose irradiation and ileum tissues were removed for light and electron microscopic investigation. Single or two dose gamma-irradiation caused a marked intestinal mucosal injury in rats. Radiation produced increases in the number of goblet cells. Using transmission electron microscopy, extensions in the area between the cells, disorders in the microvilli, mitochondrial damage and endoplasmic reticulum (ER) cisternae dilatation were observed. Antioxidant treatment with vitamin C prior to irradiation provided protection against intestinal damage.