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

Expression of syndecan-1 and cathepsins D and K in advanced esophageal squamous cell carcinoma.

The key features of malignant neoplasms are their local invasiveness and metastatic potential. Syndecan-1 - integral membrane heparan sulfate proteoglycan and cathepsins D and K - lysosomal proteases are important factors influencing different aspects of these processes. The study was undertaken to determine their expression in esophageal squamous cell carcinoma, and analyze relationship to selected clinicopathological features as well as to survival. Formalin-fixed, paraffin-embedded sections from 39 advanced esophageal squamous cell carcinoma were used for immunohistochemical staining. The epithelial and stromal staining were evaluated separately and compared to conventional clinicopathological features and one-year survival. Positive epithelial immunostaining for syndecan-1, cathepsin D and K were observed in 82.05%, 56.41% and 30.77% of tumors, respectively. However, stromal staining was noted in 51.28%, 51.28% and 46.15% ones, respectively. Epithelial syndecan-1-positive cases were significantly more frequent in well- and moderately differentiated carcinomas. Stromal cathepsin D expression predominated in tumors with infiltrative growth pattern. However, there were no statistically significant differences between any marker-positive and -negative groups with respect to other clinicopathological features studied. The only factors significantly influencing one-year survival were epithelial cathepsin D staining and distant metastasis. In a group of patients who survived one year post surgery, the percentage of cases with negative epithelial cathepsin D staining and without features of distant metastasis were higher. The results may suggest a relationship between syndecan-1 and cathepsins D and K with growth and invasiveness of esophageal squamous cell carcinoma, but such thesis requires further study on a larger and more heterogeneous population

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

The Role of Molecular and Inflammatory Indicators in the Assessment of Cognitive Dysfunction in a Mouse Model of Diabetes

The brain is the most vulnerable organ to glucose fluctuations, as well as inflammation. Considering that cognitive impairment might occur at the early stage of diabetes, it is very important to identify key markers of early neuronal dysfunction. Our overall goal was to identify neuroinflammatory and molecular indicators of early cognitive impairment in diabetic mice. To confirm cognitive impairment in diabetic mice, series of behavioral tests were conducted. The markers related to cognitive decline were classified into the following two groups: Neuroinflammatory markers: IL-1β, IL-6, tumor necrosis factor-α (TNF-α) and genetic markers (Bdnf, Arc, Egr1) which were estimated in brain regions. Our studies showed a strong association between hyperglycemia, hyperinsulinemia, neuroinflammation, and cognitive dysfunction in T2DM mice model. Cognitive impairment recorded in diabetes mice were associated not only with increased levels of cytokines but also decreased Arc and Egr1 mRNA expression level in brain regions associated with learning process and memory formation. The results of our research show that these indicators may be useful to test new forms of treatment of early cognitive dysfunction associated not only with diabetes but other diseases manifesting this type of disorders. The significant changes in Arc and Egr1 gene expression in early stage diabetes create opportunities it possible to use them to track the progression of CNS dysfunction and also to differential disease diagnosis running with cognitive impairment

The Lack of Synergy between Carvedilol and the Preventive Effect of Dexrazoxane in the Model of Chronic Anthracycline-Induced Cardiomyopathy

The anticancer efficacy of doxorubicin (DOX) is dose-limited because of cardiomyopathy, the most significant adverse effect. Initially, cardiotoxicity develops clinically silently, but it eventually appears as dilated cardiomyopathy with a very poor prognosis. Dexrazoxane (DEX) is the only FDA-approved drug to prevent the development of anthracycline cardiomyopathy, but its efficacy is insufficient. Carvedilol (CVD) is another product being tested in clinical trials for the same indication. This study’s objective was to evaluate anthracycline cardiotoxicity in rats treated with CVD in combination with DEX. The studies were conducted using male Wistar rats receiving DOX (1.6 mg/kg b.w. i.p., cumulative dose: 16 mg/kg b.w.), DOX and DEX (25 mg/kg b.w. i.p.), DOX and CVD (1 mg/kg b.w. i.p.), or a combination (DOX + DEX + CVD) for 10 weeks. Afterward, in the 11th and 21st weeks of the study, echocardiography (ECHO) was performed, and the tissues were collected. The addition of CVD to DEX as a cardioprotective factor against DOX had no favorable advantages in terms of functional (ECHO), morphological (microscopic evaluation), and biochemical alterations (cardiac troponin I and brain natriuretic peptide levels), as well as systemic toxicity (mortality and presence of ascites). Moreover, alterations caused by DOX were abolished at the tissue level by DEX; however, when CVD was added, the persistence of DOX-induced unfavorable alterations was observed. The addition of CVD normalized the aberrant expression of the vast majority of indicated genes in the DOX + DEX group. Overall, the results indicate that there is no justification to use a simultaneous treatment of DEX and CVD in DOX-induced cardiotoxicity

Evaluation of the impact of the proteasome inhibitor on calcium channel expression in cardiomyocytes treated with doxorubicin

One of the less known mechanisms of doxorubicin action is the effect on the functioning of the ubiquitin-proteasome degradation system (UPS). So far, the role of impaired proteasome activity in the development of anthracycline cardiomyopathy has not been clarified. It has been shown, however, that doxorubicin decreases the expression of proteins, including the expression of the calcium channel. However, it has not been established whether the observed disturbances are due to the activation of the UPS system by doxorubicin, or due to inhibition of translation or transcription. Therefore, the aim of the study was to evaluate the mRNA and protein expression of plasmalemmal (NaCaX, L-type) and sarcoplasmic reticulum (SERCA2, RyR2) channels in rat embryonic cardiomyocytes treated with doxorubicin and the proteasome inhibitor – bortezomib. The study was conducted utilizing the rat cardiomyocyte H9C2 line that was treated with doxorubicin and bortezomib in different concentrations. After 24 hours incubation, mRNA and protein expression analysis followed. The study did not show any universal mechanism of doxorubicin influence on calcium channel expression. With regard to the Na/Ca exchanger, we saw that DOX decreased the protein level in a proteasome activitydependent manner. Moreover, we noted that the SERCA2 protein expression level was regulated by degradation intensity, however at the same time, no significant effect of doxorubicin on the level of this protein was demonstrated

Cytotoxic activity of methanolic fractions of different Marrubium spp. against melanoma cells is independent of antioxidant activity and total phenolic content

The Marrubium genus (horehound) has proved to be an abundant source of biologically active compounds, but there is little knowledge about its potential anticancer activity. Moreover, some Marrubium species have not been the subject of study in this regard. In this study, we performed comparative analysis of phenolic acid (PhA) content and total phenolic content in fractions obtained from methanolic extracts of Marrubium vulgare L. (common horehound), Marrubium cylleneum Boiss. & Heldr. and Marrubium friwaldskyanum Boiss herbs. We examined the cytotoxicity of these fractions against a human melanoma cancer cell line (A375) and normal human skin fibroblasts (BJ) using a 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide test, cell cycle analysis and real‐time monitoring of cell viability. We detected caffeic, p‐coumaric, ferulic and gentisic acids among the PhAs. Although the extracts obtained demonstrated low total phenolic content and did not show significant antioxidative properties, the nonhydrolyzed PhA fraction exhibited cytotoxic activity against a human melanoma cancer cell line, without affecting normal fibroblasts. Both acidic and alkaline hydrolysis abolished this activity, indicating that the esterified forms of phenolic compounds caused the observed cytotoxic effects. Further investigation of these compounds may facilitate the development of novel drugs for cancer treatment

Assessment of the Impact of Carvedilol Administered Together with Dexrazoxan and Doxorubicin on Liver Structure and Function, Iron Metabolism, and Myocardial Redox System in Rats

Late cardiotoxicity is a formidable challenge in anthracycline-based anticancer treatments. Previous research hypothesized that co-administration of carvedilol (CVD) and dexrazoxane (DEX) might provide superior protection against doxorubicin (DOX)-induced cardiotoxicity compared to DEX alone. However, the anticipated benefits were not substantiated by the findings. This study focuses on investigating the impact of CVD on myocardial redox system parameters in rats treated with DOX + DEX, examining its influence on overall toxicity and iron metabolism. Additionally, considering the previously observed DOX-induced ascites, a seldom-discussed condition, the study explores the potential involvement of the liver in ascites development. Compounds were administered weekly for ten weeks, with a specific emphasis on comparing parameter changes between DOX + DEX + CVD and DOX + DEX groups. Evaluation included alterations in body weight, feed and water consumption, and analysis of NADPH2, NADP+, NADPH2/NADP+, lipid peroxidation, oxidized DNA, and mRNA for superoxide dismutase 2 and catalase expressions in cardiac muscle. The iron management panel included markers for iron, transferrin, and ferritin. Liver abnormalities were assessed through histological examinations, aspartate transaminase, alanine transaminase, and serum albumin level measurements. During weeks 11 and 21, reduced NADPH2 levels were observed in almost all examined groups. Co-administration of DEX and CVD negatively affected transferrin levels in DOX-treated rats but did not influence body weight changes. Ascites predominantly resulted from cardiac muscle dysfunction rather than liver-related effects. The study’s findings, exploring the impact of DEX and CVD on DOX-induced cardiotoxicity, indicate a lack of scientific justification for advocating the combined use of these drugs at histological, biochemical, and molecular levels

New tirapazamine derivatives protect cardiomyocytes from doxorubicin toxicity

Doxorubicin cardiotoxicity is caused by various mechanisms, most importantly by oxidative stress originating in the mitochondria. Tirapazamine is a hypoxia-activated anticancer experimental drug. Both drugs in normoxia conditions undergo univalent reduction, thus tirapazamine may compete with doxorubicin in univalent reduction enzyme uptake. Herein, tirapazamine derivatives consisted of drug molecules and alkyl chain-connected triphenylphosphine cations that bring about an accumulation in mitochondria. The aim of this study was to evaluate the interaction of newly synthesized tirapazamine derivatives with doxorubicin in rat cardiomyocytes via an vitro model. In the work, H9C2 cells were incubated with combinations of doxorubicin, tirapazamine and seven variants of tirapazamine derivatives. After 24 hours, cell viability was assessed using MTT assay and the results were confirmed by microscopic observation. Tirapazamine in all tested concentrations did not revealed significant protective activity to cardiomyocytes treated with doxorubicine. However, tirapazamine derivatives diminished the cytotoxic effect of doxorubicin regardless of concentration and alkyl chain length. Tirapazamine derivatives have shown protective effects in relation to cardiomyocytes treated with doxorubicin and the mechanism of this phenomenon must be confirmed