Slawomir Mandziuk

Different Effects of Resveratrol on Dose-Related Doxorubicin-Induced Heart and Liver Toxicity

The aim of the study was to evaluate the effect of resveratrol in doxorubicin-induced cardiac and hepatic toxicity. Doxorubicin was administered once a week throughout the period of 7 weeks with 1.0 or 2.0 mg/kg body weight or concomitantly with resveratrol (20 mg/kg of feed). Heart and liver toxicity was histologically and biochemically evaluated. Resveratrol protected from the heart lipid peroxidation caused by 1 mg doxorubicin and it sharply diminished superoxide dismutase activity. An insignificant effect of resveratrol on the lipid peroxidation level and the superoxide dismutase activity was observed in the hearts of rats administered a higher dose of doxorubicin. However, resveratrol attenuate necrosis and other cardiac histopathological changes were induced by a high dose of doxorubicin. Interestingly, it slightly intensified adverse cardiac histological changes in rats receiving a lower dose of doxorubicin. Resveratrol did not have any protective effect on the hepatic oxidative stress, while exerting a mild beneficial effect on the morphological changes caused by doxorubicin. All in all, this study has shown different effects of resveratrol on dose-related doxorubicin-induced heart and liver toxicity. Resveratrol may modulate the hepatic and cardiac effect of doxorubicin, depending on the drug dose.

The Redox Imbalance and the Reduction of Contractile Protein Content in Rat Hearts Administered with L-Thyroxine and Doxorubicin

Oxidative stress and disorders in calcium balance play a crucial role in the doxorubicin-induced cardiotoxicity. Moreover, many cardiotoxic targets of doxorubicin are regulated by iodothyronine hormones. The aim of the study was to evaluate effects of tetraiodothyronine (0.2, 2 mg/L) on oxidative stress in the cardiac muscle as well as contractility and cardiomyocyte damage markers in rats receiving doxorubicin (1.5 mg/kg) once a week for ten weeks. Doxorubicin was administered alone (DOX) or together with a lower (0.2T4 + DOX) and higher dose of tetraiodothyronine (2T4 + DOX). Two groups received only tetraiodothyronine (0.2T4, 2T4). Coadministration of tetraiodothyronine and doxorubicin increased the level of lipid peroxidation products and reduced RyR2 level when compared to untreated control and group exposed exclusively to doxorubicin. Insignificant differences in SERCA2 and occasional histological changes were observed. In conclusion, an increase of tetraiodothyronine level may be an additional risk factor of redox imbalance and RyR2 reduction in anthracycline cardiotoxicity.

The differential effects of green tea on dose-dependent doxorubicin toxicity

Background Doxorubicin (DOX) is an anticancer drug displaying cardiac and hepatic adverse effects mostly dependent on oxidative stress. Green tea (GT) has been reported to play a protective role in diseases resulting from oxidative stress. Objective The objective of this study was to evaluate if GT protects against DOX-induced oxidative stress, heart and liver morphological changes, and metabolic disorders. Methods Male Wistar rats received intraperitoneal injection of DOX (1.0 or 2.0 mg/kg b.w.) for 7 weeks or concomitantly GT extract soluble in drinking water. Results There were multidirectional effects of GT on blood metabolic parameters changed by DOX. Among all tested biochemical parameters, statistically significant protection of GT against DOX-induced changes was revealed in case of blood fatty acid–binding protein, brain natriuretic peptide, and superoxide dismutase. Conclusion DOX caused oxidative stress in both organs. It was inhibited by GT in the heart but remained unchanged in the liver. DOX-induced general toxicity and histopathological changes in the heart and in the liver were mitigated by GT at a higher dose of DOX and augmented in rats treated with a lower dose of the drug.

Protective effect of Mutellina purpurea polyphenolic compounds in doxorubicin-induced toxicity in H9c2 cardiomyocytes

Abstract The delayed cardiomyopathy caused by doxorubicin – an chemotherapeutic drug with broad spectrum of anticancer activity – is mainly triggered by oxidative stress. The aim of this study was to assess an effect of Mutellina purpurea methanolic extract fraction and other antioxidants of plant origin: rutin, quercetin and chlorogenic acid (all 1 mg% w/v) on oxidative stress and morphological changes induced by doxorubicin in cardiomyocytes H9c2. Mitochondrial oxidative stress in cardiomyocytes induced by 1 µM doxorubicin was evidenced by MitoTracker and RedoxSensor Red CC-1 dyes. Moreover, cardiomyocytes morphological changes and cell viability were evaluated. The tested fraction slightly reduced mitochondrial ROS fluorescence, similar to quercetin. Chlorogenic acid revealed concentration dependent prooxidative and antioxidative properties in the applied H9c2 model. The evaluation of the protective effect of tested compounds on doxorubicin-induced cytotoxicity was based on the examination of induced oxidative stress and morphology changes. The protective effect was described in the following order: rutin > chlorogenic acid (0.5 µM) > LH8 and quercetin. According to the MTT test, rutin seems to be the most promising compound that should be tested in a future studies.

Tirapazamine-Doxorubicin Interaction Referring to Heart Oxidative Stress and Ca2+ Balance Protein Levels

Doxorubicin (DOX) causes long-term cardiomyopathy that is dependent on oxidative stress and contractility disorders. Tirapazamine (TP), an experimental adjuvant drug, passes the same red-ox transformation as DOX. The aim of the study was to evaluate an effect of tirapazamine on oxidative stress, contractile protein level, and cardiomyocyte necrosis in rats administered doxorubicin. Rats were intraperitoneally injected six times once a week with tirapazamine in two doses, 5 (5TP) and 10 mg/kg (10TP), while doxorubicin was administered in dose 1.8 mg/kg (DOX). Subsequent two groups received both drugs simultaneously (5TP+DOX and 10TP+DOX). Tirapazamine reduced heart lipid peroxidation and normalised RyR2 protein level altered by doxorubicin. There were no significant changes in GSH/GSSG ratio, total glutathione, cTnI, AST, and SERCA2 level between DOX and TP+DOX groups. Cardiomyocyte necrosis was observed in groups 10TP and 10TP+DOX.

Tirapazamine has no Effect on Hepatotoxicity of Cisplatin and 5‐fluorouracil but Interacts with Doxorubicin Leading to Side Changes in Redox Equilibrium

Tirapazamine is a hypoxia‐activated prodrug which was shown to exhibit up to 300 times greater cytotoxicity under anoxic in comparison with aerobic conditions. Thus, the combined anticancer therapy of tirapazamine with a routinely used anticancer drug seems to be a promising solution. Because tirapazamine undergoes redox cycle transformation in this study, the effect of tirapazamine on redox hepatic equilibrium, lipid status and liver morphology was evaluated in rats exposed to cisplatin, doxorubicin and 5‐fluorouracil. Rats were intraperitoneally injected with tirapazamine and a particular cytostatic. The animals were killed, and blood and liver were collected. Hepatic glucose, total cholesterol, triglycerides, NADH, NADPH glutathione and the activity of glucose‐6‐phosphate dehydrogenase were determined. Liver morphology and the immune expression of HMG‐CoA‐reductase were also assessed. Glucose, total cholesterol, triglycerides, bilirubin concentrations and the activity of aspartate and alanine aminotransferases were determined in the plasma. Tirapazamine displayed insignificant interactions with cisplatin and 5‐fluorouracil referring to hepatic morphology and biochemical parameters. However, tirapazamine interacts with doxorubicin, thus leading to side changes in redox equilibrium and lipid peroxidation, but those effects are not severe enough to exclude that drug combination from further studies. Thus, tirapazamine seems to be a promising agent in successive studies on anticancer activity in similar schedules.

The effect of thyroxin on hepatic redox equilibrium and lipid metabolism in rats treated with doxorubicin

Abstract The main side effects of the administration of doxorubicin, a widely used anticancer drug, is the generation of a reactive oxygen species (ROS) in normal cells. As a result, redox disorders and secondary oxidative stress are developed. Doxorubicin ROS generation is attributed to enzymes that are produced abundantly in hepatocytes. Oxidative stress has been a well-known risk factor of doxorubicin-related toxicity. However, in addition, according to the data collected in the last decade, changes in thyroxin status can propagate ROS generation, and, thus, initiate the doxorubicin hepatic effect. Moreover, both compounds have an impact on the cell metabolism. The aim of the study was to verify the thesis that thyroxin can modulate the effect of doxorubicin with regard to redox status and lipid metabolism disorders. In our work, we determined the ratio of NADP+/ NADPH and NAD+/NADH in liver homogenates, blood ketone bodies and triglycerides in the liver and blood in rats treated with doxorubicin and thyroxin. Our results indicate that thyroxin has an insignificant effect on NAD+/NADH, NADP+/NADPH ratios and on hepatic and blood triglycerides. Moreover, thyroxin administration normalized the level of blood ketone bodies that was disturbed by doxorubicin.

The effect of one-electron reduced drugs on hepatic aconitase activity and triglycerides level

Abstract The redox cycle triggered by one electron reduction of doxorubicin and tirapazamine - both anticancer agents - leads to superoxide production. This superoxide production itself removes one iron atom from the [4Fe-4S] cluster, being an active center of aconitase. In addition, the incurred changes in cell redox equilibrium may affect lipid metabolism. The aim of the study was to evaluate a concomitant effect of both drugs on hepatic aconitase activity and triglycerides level. In our study, doxorubicin (1.8 mg/kg b.w.) was administered intraperitoneal (i.p.) six times, once a week, within male Wistar rats, to achieve a cumulative dose of 10.8 mg/kg b.w. Two hours before every doxorubicin administration, tirapazamine in the dose of either 5 or 10 mg/kg b.w. was also i.p. injected. A week after withdrawing drug administration, the liver was taken for biochemical analysis. Therein, an increase in aconitase activity and a decrease in triglycerides level was seen in all groups exposed to doxorubicin. Our work demonstrated that tirapazamine administration had no influence on both tested parameters, but its higher dose rate normalized aconitase activity affected by doxorubicin.

Inhibition of Rho kinase by GSK 269962 reverses both corticosterone-induced detrusor overactivity and depression-like behaviour in rats

ABSTRACT Literature data give clear evidence that upregulated RhoA/Rho‐kinase signalling is one of the factors that may lead to the development of detrusor overactivity and various disorders of the central nervous system. Therefore, the main objective of our study was to investigate whether administration of a Rho‐kinase inhibitor – GSK 269962 could reverse corticosterone‐induced depressive‐like behaviour and changes in cystometric parameters associated with detrusor overactivity, as well as undo the alterations of several biomarkers related to both disorders (i.e., pro‐inflammatory/anti‐inflammatory cytokines and neurotrophins) in serum, urinary bladder, and different brain structures. The experiments were carried out on female Wistar rats. Surgical procedures, cystometric investigations, biochemical analyses, and behavioural studies (measurement of the locomotor activity and the forced swim test) were performed according to the published literature. As expected, administration of corticosterone at a daily dose of 20mg/kg for 14 days increased the immobility time of animals in the forced swim test, induced changes in the cystometric parameters specific to bladder overactivity, reduced levels of neurotrophins, and elevated concentrations of the pro‐inflammatory cytokines. Inhibition of Rho‐kinase by 7‐day treatment with GSK 269962 (10mg/kg/day) reversed the symptoms of both detrusor overactivity and depression as well as normalized levels of the tested biomarkes. Our findings encourage the idea of Rho‐kinase inhibitors as a potential future treatment option for overactive bladder accompanied by depression.

Analysis of KRAS, NRAS, BRAF, and PIK3CA mutations could predictmetastases in colorectal cancer: A preliminary study

BACKGROUND Colorectal cancer (CRC) is usually diagnosed in the metastatic stage, when chemotherapy and molecularly-targeted therapies, instead of surgery, play the most important therapeutic role. Application of anti-epidermal growth factor receptor (EGFR) therapy requires the analysis of RAS mutation status and only RAS wild-type (wt) patients are qualified for the therapy. OBJECTIVES The objective of this study was to analyze driver mutations in KRAS, NRAS, BRAF, and PIK3CA genes in CRC patients. MATERIAL AND METHODS We assessed the KRAS, NRAS, BRAF, and PIK3CA genes in 102 inoperable, locally advanced and advanced CRC patients. Real-time polymerase chain reaction (RT-PCR) and high resolution melt PCR (HRM-PCR) techniques with DNA intercalating dye were applied in the study. RESULTS Forty-six patients demonstrated the presence of examined mutations (45.1%). No significant differences in driver mutation occurrence between men and women, as well as between younger (<65 years) and older (≥65 years) patients were found. The mutations were present significantly more frequently in metastatic than in primary tumors (p = 0.039) due to the high incidence of KRAS gene mutations in metastatic tissue. BRAF and PIK3CA mutations were found only in primary tumors. The incidence of PIK3CA mutations was significantly higher (11.77%) in early than in advanced stages of the disease (1.96%; p = 0.05); NRAS mutations were found only in metastatic cancer (7.85%; p = 0.041). Only a single mutation of the PIK3CA and no mutations of NRAS were found in rectal cancer. CONCLUSIONS Our results have shown low occurrence of driver mutations in Polish CRC patients, involving also mutations in rarely tested genes. The extent of the research panel of additional mutations could contribute to creating a better method of qualifying patients for molecularly targeted therapies and obtaining a better outcome for these therapeutic strategies.