Differential effects of cisplatin on mouse hepatic and renal mitochondrial DNA

Demonstration of the protective effect of ghrelin in the livers of rats with cisplatin toxicity

Despite the various and newly developed chemotherapeutic agents in recent years, cisplatin is still used very frequently as a chemotherapeutic agent, even though cisplatin has toxic effects on many organs. The aim of our study is to show whether ghrelin reduces the liver toxicity of cisplatin in the rat model. Twenty-eight male Sprague Dawley albino mature rats were chosen to be utilized in the study. Group 1 rats (n = 7) were taken as the control group, and no medication was given to them. Group 2 rats (n = 7) received 5 mg/kg/day cisplatin and 1 ml/kg/day of 0.9% NaCl, Group 3 rats (n = 7) received 5 mg/kg/day cisplatin and 10 ng/kg/day ghrelin, Group 4 rats (n = 7) received 5 mg/kg/day cisplatin and 20 ng/kg/day ghrelin for 3 days. Glutathione, malondialdehyde (MDA), superoxide dismutase (SOD), plasma alanine aminotransferase (ALT) levels, and liver biopsy results were measured in rats. It was determined that, especially in the high-dose group, the MDA, plasma ALT, and SOD levels increased less in the ghrelin group as compared to the cisplatin group, and the glutathione level decreased slightly with a low dose of ghrelin, while it increased with a higher dose. In histopathological examination, it was determined that the toxic effect of cisplatin on the liver was reduced with a low dose of ghrelin, and its histopathological appearance was similar to normal liver tissue when given a high dose of ghrelin. These findings show that ghrelin, especially in high doses, can be used to reduce the toxic effect of cisplatin.

The abrupt pathological deterioration of cisplatin-induced acute kidney injury: Emerging of a critical time point

Cisplatin (CP), an anticancer drug, often causes kidney damage. However, the mechanism of CP-induced acute kidney injury (AKI) is not completely understood. AKI was induced by intravenous injection (i.v.) of cisplatin at doses of 5, 8, and 10 mg/kg. Anemoside B4 (B4) (20 mg/kg, i.m.) and dexamethasone (DXM) (0.5 mg/kg, i.v.) were used for AKI treatment. Biochemical indicators were assessed using an automatic biochemical analyzer, protein expression was analyzed by western blotting, and morphological changes in the kidney were examined by PAS staining. The serum creatinine (Cre) and blood urea nitrogen (BUN) levels did not change significantly in the first 2 days but abruptly increased on the third day after CP injection. The serum albumin (ALB) and total protein (TP) levels decreased in both a time- and dose-dependent manner. The urine protein level increased, the clearing rate of Cre decreased distinctly, and morphologic changes appeared in a dose-dependent manner. The protein expression of p53/caspase-3, NLRP3, IL-6, and TNF-α was obviously upregulated on day 3; concurrently, nephrin and podocin were downregulated. The expression of LC3II and p62 was upregulated significantly as the CP dose increased. B4 and DXM obviously decreased the BUN and Cre levels after 3 or 5 days of treatment. AKI appeared distinctly in a time-dependent manner at 2 to 5 days after the administration of 5 mg/kg CP and in a dose-dependent manner upon the administration of 5, 8, and 10 mg/kg CP. The third day was a significant time point for renal deterioration, and treatment with B4 and DXM within the first 3 days provided significant protection against AKI.

Mitochondrial quality control in kidney injury and repair

Mitochondria are essential for the activity, function and viability of eukaryotic cells and mitochondrial dysfunction is involved in the pathogenesis of acute kidney injury (AKI) and chronic kidney disease, as well as in abnormal kidney repair after AKI. Multiple quality control mechanisms, including antioxidant defence, protein quality control, mitochondrial DNA repair, mitochondrial dynamics, mitophagy and mitochondrial biogenesis, have evolved to preserve mitochondrial homeostasis under physiological and pathological conditions. Loss of these mechanisms may induce mitochondrial damage and dysfunction, leading to cell death, tissue injury and, potentially, organ failure. Accumulating evidence suggests a role of disturbances in mitochondrial quality control in the pathogenesis of AKI, incomplete or maladaptive kidney repair and chronic kidney disease. Moreover, specific interventions that target mitochondrial quality control mechanisms to preserve and restore mitochondrial function have emerged as promising therapeutic strategies to prevent and treat kidney injury and accelerate kidney repair. However, clinical translation of these findings is challenging owing to potential adverse effects, unclear mechanisms of action and a lack of knowledge of the specific roles and regulation of mitochondrial quality control mechanisms in kidney resident and circulating cell types during injury and repair of the kidney.

The protective effect of pomegranate extract against cisplatin toxicity in rat liver and kidney tissue

OBJECTIVES

The purpose of this study was to perform a histopathological investigation, at the light microscopy level, of the protective effects of pomegranate extract in cisplatin-induced liver and kidney damage in rats.

MATERIAL AND METHODS

Twenty-eight adult male Wistar albino rats were randomly divided into four groups of seven animals: Group 1: Control; Group 2: Treated for 10 consecutive days by gavage with pomegranate juice (2 ml/kg/day); Group 3: Injected intraperitoneally with cisplatin (8 mg/kg body weight, single dose) onset of the day 5, and Group 4: Treated by gavage with pomegranate juice 10 days before and after a single injection of cisplatin onset of the day 5. After 10 days, the animals were sacrificed and their kidneys and liver tissue samples were removed from each animal after experimental procedures. Cisplatin-induced renal and hepatic toxicity and the effect of pomegranate juice were evaluated by histopatological examinations.

RESULTS

In the kidney tissue, pomegranate juice significantly ameliorated cisplatin-induced structural alterations when compared with the cisplatin alone group. But in the liver tissue, although pomegranate juice attenuated the cisplatin-induced toxicity only in two rats, significant improvement was not observed.

CONCLUSION

In conclusion, these results demonstrate that the anti-oxidant pomegranate juice might have a protective effect against cisplatin-induced toxicity in rat kidney, but not in liver. Pomegranate juice could be beneficial as a dietary supplement in patients receiving chemotherapy medications.

Prediction of nephrotoxicity induced by cisplatin combination chemotherapy in gastric cancer patients

AIM: To evaluate the treatment options for nephrotoxicity due to cisplatin combination chemotherapy.

METHODS: We retrospectively reviewed patients who had received cisplatin combination chemotherapy for gastric cancer between January 2002 and December 2008. We investigated patients who had shown acute renal failure (ARF), and examined their clinical characteristics, laboratory data, use of preventive measures, treatment cycles, the amount of cisplatin administered, recovery period, subsequent treatments, and renal status between the recovered and unrecovered groups.

RESULTS: Forty-one of the 552 patients had serum creatinine (SCR) levels greater than 1.5 mg/dL. We found that pre-ARF SCR, ARF SCR, and ARF glomerular filtration rates were significantly associated with renal status post-ARF between the two groups (P = 0.008, 0.026, 0.026, respectively). On the receiver operating characteristic curve of these values, a 1.75 mg/dL ARF SCR value had 87.5% sensitivity and 84.8% specificity (P = 0.011).

CONCLUSION: Cessation or reduction of chemotherapy should be considered for patients who have an elevation of SCR levels during cisplatin combination chemotherapy.

Cisplatin-mediated impairment of mitochondrial DNA metabolism inversely correlates with glutathione levels

Cisplatin accumulates in mitochondria, which are a major target for this drug in cancer cells. Thus alterations in mitochondrial function have been implicated in cancer cell resistance to chemotherapeutic agents. Moreover, cisplatin toxic side effects seem to be associated with mitochondrial injury in vivo and in vitro. In order to clarify the potential effect of cisplatin in mtDNA (mitochondrial DNA) maintenance and expression, we have analysed rat liver mtDNA and mtRNA (mitochondrial RNA) synthesis as well as their stability under the influence of in vivo treatment or in vitro exposure to cisplatin. We show that cisplatin causes a direct and significant impairment of mtDNA and mtRNA synthesis and decreases steady-state levels of mtRNAs in isolated mitochondria. Furthermore, in vivo treatment of the animals with cisplatin exerts a protective effect from the impairment of mtRNA metabolism caused by in vitro exposure to the drug, by means of increased mitochondrial GSH levels after in vivo cisplatin treatment.

Cisplatin induces mitochondrial oxidative stress with resultant energetic metabolism impairment, membrane rigidification and apoptosis in rat liver

Cisplatin is a potent and widely used chemotherapeutic agent. Nephrotoxicity induced by this drug has been well documented. However, very little information is available on cisplatin-induced hepatotoxicity and its underlying mechanism remains unclear. High doses of cisplatin have been known to produce hepatotoxicity. Additionally, elevated expression of CYP 2E1 has been associated with enhanced cisplatin-induced hepatotoxicity. Several studies suggest that cisplatin toxicity occurs by the increased generation of reactive oxygen species (ROS) in mitochondria. Therefore, the present study examined, in vivo, the cisplatin-induced effects on hepatic mitochondrial structure and function as well as the occurrence of hepatocellular death by apoptosis. Adult male Wistar rats (200-220 g) were divided into two groups (n=8) treated as follows: (1) control group (saline solution, 1 ml 100 g(-1) body weight, i.p.) and (2) cisplatin group (10 mg kg(-1) body weight, i.p.). The animals were killed 72 h after the treatment. Hepatotoxicity was evidenced in the cisplatin group by the increased serum levels of alanine (ALT) and aspartate (AST) aminotransferases. The mechanism of cisplatin-induced hepatotoxicity was found to involve membrane rigidification; decreased GSH/GSSG ratio, ATP, GSH and NADPH levels; lipid peroxidation; oxidative damage of cardiolipin and protein sulfhydryl groups. Moreover, cell death by apoptosis was also demonstrated and the findings strongly suggest the participation of the mitochondrial signaling pathway in this process. Therefore, the results show the key role of mitochondria in the hepatotoxicity induced by cisplatin and delineate several mitochondrial processes that could be targeted in future cytoprotective therapy approaches.

Pharmacokinetics and tissue distribution of novel traditional Chinese medicine-platinum anticancer agents in rats

The pharmacokinetics and tissue distribution profiles of a novel series of traditional Chinese medicine-platinum (TCM-Pt) compounds [Pt(C(8)H(8)O(5))(NH(2)R)(2)]: 1 (where R=H), 3 (R=CH(3)) and 5 (R=C(6)H(10)), were studied in Sprague-Dawley rats following a single bolus intravenous (i.v.) injection. Platinum concentrations in total plasma, plasma ultrafiltrate, urine and tissues were measured by flameless atomic absorption spectroscopy. Pharmacokinetic studies showed that plasma concentrations of total and free platinum for the novel TCM-Pt compounds as well as cisplatin and carboplatin declined in a biexponential manner with a short distribution half-life (t(1/2alpha): 0.12-0.34h). Compared with cisplatin, the novel TCM-Pt compounds had a longer elimination half-life (t(1/2beta)), larger dose normalized area under the curve (AUC/D), larger volume of distribution at steady-state (V(ss)), slower clearance (CL) of free platinum and higher percentage of cumulative urinary excretion (CUE), which can be attributed to their lower chemical reactivities. In tissues, the highest Pt concentrations were found in the kidney, followed by the liver and the lowest in the heart; no Pt was detected in the brain. Twenty-four hours after drug administration, platinum concentrations in tissues were significantly lower for the novel TCM-Pt compounds. These findings suggest that the novel compounds might afford higher clinical efficacy and reduced systemic side effects, when compared with cisplatin.

Depletion of mitochondrial DNA and enzyme in estrogen-induced hamster kidney tumors: a rodent model of hormonal carcinogenesis

Mitochondrial DNA (mtDNA) encodes for 13 polypeptides critical for normal functioning of the electron transport chain and damage to mtDNA has been associated with aging, and implicated in several disease processes. Although damage to mtDNA is being implicated in mutagenesis and carcinogenesis, there are limited studies demonstrating the role and extent of mtDNA damage in human or rodent cancers. Using serial dilution and competitive polymerase chain reaction analysis, we have quantitated the amount of total mtDNA and analyzed the extent of mtDNA damage in estrogen-induced and estrogen-dependent hamster kidney tumors. The hamster kidney tumor model is a useful and widely investigated rodent model of hormonal carcinogenesis, which shares several characteristics with human breast and uterine cancers, and point to a common mechanistic pathway. Our data indicate a significant decrease in the copy number of total mtDNA and the activity of a nuclear-encoded mitochondrial enzyme citrate synthase in hamster kidney tumors compared to age-matched controls. Since there are several hundred mitochondria in a cell and each mitochondrion has multiple copies of mtDNA, a very small percentage of somatic deletion mutation may not be enough to result in a decreased capacity of the mitochondrial genome. However, a significant increase in deletion mutations or a decrease in the mtDNA copy number can result in a decreased oxidative phosphorylation capacity of the mitochondria and decreased energetics, and thus increased susceptibility to the disease process. Therefore, estrogen-induced hamster kidney tumor model can be a useful rodent model of carcinogenesis to understand the role of mtDNA damage in cancer progression and development.

Cisplatin exposure induces mitochondrial toxicity in pregnant rats and their fetuses

High levels of cis-diamminedicholorplatinum II (cisplatin)-DNA adducts have previously been observed at term in mitochondrial DNA (mtDNA) from organs of pregnant rats, and from their offspring, after administration of a single injection of cisplatin 15 mg/kg body weight (bw) to the pregnant rat on day 18 of gestation. The consequences of such DNA damage may be clinically relevant as cisplatin is given to pregnant women discovered to have ovarian cancer during pregnancy. In this study, kidneys, livers, and brains of exposed pregnant rats and their offspring were examined for mitochondrial functional integrity. Consistent with previous literature, the most severe toxicity occurred in maternal kidney, where oxidative phosphorylation (OXPHOS) enzyme activities were significantly (approximately 50%) impaired for Complexes II, III, and IV, mtDNA levels in drug-exposed animals were higher than in the unexposed controls, and abnormal mitochondrial morphology was observed by transmission electron microscopy (TEM). In fetal kidneys and livers, cisplatin exposure did not alter mitochondrial morphology or mtDNA quantity, but specific activities of OXPHOS Complexes II and IV were significantly decreased. Fetal brain sustained no discernible mitochondrial toxicity. Therefore, cisplatin-induced mitochondrial toxicity in maternal rat kidney is severe, while damage to mitochondria in fetal kidney and liver, occurring as a result of the transplacental drug exposure, appears to be mild.

Abnormal lipid and fatty acid compositions of kidneys from mice with polycystic kidney disease

Renal cyst development in polycystic kidney disease (PKD) involves hyperplastic growth and extensive membrane alterations, suggesting abnormal membrane composition and function. Using thin-layer and gas-liquid chromatography, we analyzed the lipid components of the kidneys from 120-day-old DBA/2FG-pcy (pcy) having PKD as compared to normal DBA/2J (DBA) mice. At sacrifice, kidneys from pcy mice were four times larger than DBA controls, indicating that extensive renal cyst growth had occurred. The ratios of cholesterol/phospholipid, choline glycerophospholipid (GPC)/ethanolamine glycerophospholipid (GPE) and alkenylacyl GPE/diacyl GPE were higher (by 25%, 41% and 72%, respectively) in the cystic kidneys, while total phosphatidylinositol (PI), GPE and cardiolipin (DPG) were lower (by 13%, 23% and 27%, respectively). With respect to fatty acid compositions, there were significantly lower levels of docosahexaenoic acid (DHA, 22:6n-3) and higher levels of adrenic acid (AdA, 22:4n-6) in the phospholipids of pcy mouse kidneys. These changes were not present in serum, indicating that they were not generalized differences. Interestingly, the lower level of DHA in GPE was found to be associated with the alkenylacyl, but not the diacyl species. The fatty acids comprising the product/substrate ratio for the delta 4 desaturase activity were lower across all phospholipids, indicating a possible abnormality in polyunsaturated fatty acid metabolism in this model of PKD. These lipid abnormalities may influence membrane-mediated events such as receptor activation, signal transduction, ion transport and enzyme activities. The renal pathophysiologies associated with PKD may be related to the tissue lipid abnormalities described herein.

Mitochondrial DNA damage by anticancer agents

Mitochondrial DNA (mtDNA) is susceptible to damage by a number of anticancer agents either directly or indirectly. This damage is of little consequence if only a few of the mtDNA molecules are damaged. However, multiple drug treatments could result in a significant effect on a cell's ability to survive. The differential effect of anticancer agents on either organ specific toxicities or selective tumor kill can be partially accounted for by differential mtDNA content of cells and on the basis of differential protective mechanisms within mitochondria of various organs or tumor tissue. The concept of damage to mitochondria, especially its genome, is a subject of active investigation in various laboratories. This area of research may provide mechanism(s) by which organ specific toxicities or tumor specific toxicities may be elaborated. Also, the concept of targeting tumor specific mitochondria and/or mtDNA by anticancer agents is very attractive but has not come to fruition due to a lack of understanding of the regulation of the genome in tumor cells. Future investigations in this arena will enhance our knowledge on the interaction between anticancer agents and extranuclear DNA.

Evidence for lack of mitochondrial DNA repair following cis-dichlorodiammineplatinum treatment

The purpose of this study was to determine whether cis-dichlorodiammineplatinum (cisplatin) causes mitochondrial DNA (mtDNA) damage. A specific and sensitive method for quantitation of damage to mtDNA was used, by which the physical forms of mtDNA (supercoiled, open circular and linear forms) were separated by gel electrophoresis. The DNA specificity was then obtained by hybridizing with a mtDNA probe. In vitro incubation of mtDNA with cisplatin showed that the drug did not induce any changes in the proportion of physical forms; similar results were obtained in vivo. Since cisplatin did not cause any strand scission in mtDNA but induces strand breaks in nuclear DNA, which is an indirect effect, a lack of repair for cisplatin-induced adducts in mtDNA is suggested.