Cardioprotective Effects of Subcutaneous Ebselen against Daunorubicin-Induced Cardiomyopathy in Rats

Ebselen: A Review on its Synthesis, Derivatives, Anticancer Efficacy and Utility in Combating SARS-COV-2

Ebselen is a selenoorganic chiral compound with antioxidant properties comparable to glutathione peroxidase. It is also known as 2-phenyl-1,2-benzisoselenazol-3(2H)-one. In studies examining its numerous pharmacological activities, including antioxidant, anticancer, antiviral, and anti- Alzheimer's, ebselen has demonstrated promising results. This review's primary objective was to emphasize the numerous synthesis pathways of ebselen and their efficacy in fighting cancer. The data were collected from multiple sources, including Scopus, PubMed, Google Scholar, Web of Science, and Publons. The starting reagents for the synthesis of ebselen are 2-aminobenzoic acid and N-phenyl benzamide. It was discovered that ebselen has the ability to initiate apoptosis in malignant cells and prevent the formation of new cancer cells by scavenging free radicals. In addition, ebselen increases tumor cell susceptibility to apoptosis by inhibiting TNF-α mediated NF-kB activation. Ebselen can inhibit both doxorubicin and daunorubicin-induced cardiotoxicity. Allopurinol and ebselen administered orally can be used to suppress renal ototoxicity and nephrotoxicity. Due to excessive administration, diclofenac can induce malignancy of the gastrointestinal tract, which ebselen can effectively suppress. Recent research has demonstrated ebselen to inhibit viral function by binding to cysteinecontaining catalytic domains of various viral proteases. It was discovered that ebselen could inhibit the catalytic dyad function of Mpro by forming an irreversible covalent bond between Se and Cys145, thereby altering protease function and inhibiting SARS-CoV-2. Ebselen may also inhibit the activation of endosomal NADPH oxidase of vascular endothelial cells, which is believed to be required for thrombotic complications in COVID-19. In this review, we have included various studies conducted on the anticancer effect of ebselen as well as its inhibition of SARS-CoV-2.

Toxicology and pharmacology of synthetic organoselenium compounds: an update

Here, we addressed the pharmacology and toxicology of synthetic organoselenium compounds and some naturally occurring organoselenium amino acids. The use of selenium as a tool in organic synthesis and as a pharmacological agent goes back to the middle of the nineteenth and the beginning of the twentieth centuries. The rediscovery of ebselen and its investigation in clinical trials have motivated the search for new organoselenium molecules with pharmacological properties. Although ebselen and diselenides have some overlapping pharmacological properties, their molecular targets are not identical. However, they have similar anti-inflammatory and antioxidant activities, possibly, via activation of transcription factors, regulating the expression of antioxidant genes. In short, our knowledge about the pharmacological properties of simple organoselenium compounds is still elusive. However, contrary to our early expectations that they could imitate selenoproteins, organoselenium compounds seem to have non-specific modulatory activation of antioxidant pathways and specific inhibitory effects in some thiol-containing proteins. The thiol-oxidizing properties of organoselenium compounds are considered the molecular basis of their chronic toxicity; however, the acute use of organoselenium compounds as inhibitors of specific thiol-containing enzymes can be of therapeutic significance. In summary, the outcomes of the clinical trials of ebselen as a mimetic of lithium or as an inhibitor of SARS-CoV-2 proteases will be important to the field of organoselenium synthesis. The development of computational techniques that could predict rational modifications in the structure of organoselenium compounds to increase their specificity is required to construct a library of thiol-modifying agents with selectivity toward specific target proteins.

Mechanisms of ebselen as a therapeutic and its pharmacology applications

Ebselen is a synthetic organoselenium radical scavenger compound that possesses glutathione peroxidase-like activity and its own unique bioactivity by reacting with thiols, hydroperoxides and peroxynitrites. Owing to its high affinity toward several essential reactions, ebselen protects cellular components from oxidative and free radical damage, and it has been employed as a useful tool for studying redox-related mechanisms. Based on numerous in vitro and in vivo research, mechanisms are proposed to understand the biomedical and molecular actions of ebselen in health and disease, and it is currently under clinical trials for the prevention and treatment of various human disorders. Based on these outstanding discoveries, this review summarizes the current understanding of the biochemical and molecular characteristics, pharmacological applications and future directions of ebselen.

Fisetin, a plant flavonoid ameliorates doxorubicin-induced cardiotoxicity in experimental rats: the decisive role of caspase-3, COX-II, cTn-I, iNOs and TNF-α

Doxorubicin (DOX) is a widely used anthracycline antibiotic for the management of carcinoma. However, it is associated with cardiotoxicity. Fisetin is a plant flavonoid reported to have anti-inflammatory and antiapoptotic potential. To evaluate the cardioprotective potential of fisetin in DOX-induced cardiotoxicity in experimental rats. Sprague-Dawley rats were pre-treated with either fisetin (10, 20 and 40 mg/kg) or sitagliptin (10 mg/kg, p.o.) for 7 days. Cardiac toxicity was induced in rats (except the normal group) by doxorubicin (15 mg/kg i.p.) on 8th day. Various behavioral, biochemical, molecular and histological parameters were assessed in cardiac tissue. DOX-induced alterations in electrocardiographic, hemodynamic and left ventricular function were significantly (p < 0.05) inhibited by fisetin (20 and 40 mg/kg) treatment. Fisetin significantly decrease (p < 0.05) DOX-induced elevated serum CK-MB, LDH, AST, ALT and ALP levels. DOX-induced elevated cardiac oxido-nitrosative (SOD, GSH, MDA and NO) was significantly inhibited (p < 0.05) by fisetin. Up-regulated cardiac caspase-3, COX-II, cTn-I, iNOs, TNF-α, and IL-1β mRNA, as well as protein expressions were significantly decreased (p < 0.05) by fisetin treatment. It also significantly (p < 0.05) attenuated DOX-induced histopathological alterations in cardiac tissue. In conclusion, the fisetin exerts its cardioprotective potential against DOX-induced toxicity via inhibition of multiple pathways including oxidative stress (SOD, GSH, MDA and NO), inflammation (COX-II, TNF-α, and IL-1β), and apoptosis (Caspase-3). Therefore, fisetin can be considered as a potential cardioprotective agent during the management of carcinoma using doxorubicin anthracyclines.

Enoxaparin attenuates doxorubicin induced cardiotoxicity in rats via interfering with oxidative stress, inflammation and apoptosis

Background

Doxorubicin (DOX) is commonly used in the treatment of many types of cancers but its cardiotoxicity is limiting its clinical use. Beyond its anticoagulant action, enoxaparin (ENX), a low molecular weight heparin, has been shown to exert multiple pharmacological actions including antioxidant, anti-inflammatory and antiapoptotic effects. Therefore, the current study aimed to assess if ENX could ameliorate cardiotoxicity induced by DOX.

Methods

Twenty-one adult male Wistar albino rats were randomly allocated into three groups (n = 7 each) of control, receiving 0.9% saline (i.p.), DOX, receiving 2.5 mg/kg of DOX (i.p.) thrice weekly; and DOX + ENX, receiving ENX (250 IU/kg/day i.p.) and a DOX dose equivalent to that of the DOX only group.

Results

DOX-induced cardiotoxicity was indicated by marked increases in cardiac troponin I (cTnI) and severe histological lesions, which significantly correlated with cardiotoxicity, oxidative stress, inflammation and apoptosis markers, compared to controls. DOX group also showed elevations in malondialdehyde (MDA), a marker of oxidative stress, and reductions in total antioxidant capacity (TAC). Cardiac inflammatory markers including tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) and caspase-3, an apoptotic marker, were also elevated in the DOX group. DOX, however, did not significantly alter brain natriuretic peptide (BNP) levels. ENX significantly attenuated, but not completely reversed, DOX-induced cardiotoxicity through lowering cTnI and improving cardiomyopathy histopathological scores as compared to the DOX group. ENX also decreased MDA, increased TAC of rats’ heart to levels relatively comparable to control. Significant reductions in TNF-α, IL-1β and caspase-3 were also observed following ENX treatment relative to the DOX only group.

Conclusions

Collectively, these results describe a cardioprotective effect for ENX against DOX-induced cardiotoxicity which is likely facilitated via suppression of oxidative stress, inflammation and apoptosis.

Association of oxidative stress to the genesis of anxiety: implications for possible therapeutic interventions

Oxidative stress caused by reactive species, including reactive oxygen species, reactive nitrogen species, and unbound, adventitious metal ions (e.g., iron [Fe] and copper [Cu]), is an underlying cause of various neurodegenerative diseases. These reactive species are an inevitable by-product of cellular respiration or other metabolic processes that may cause the oxidation of lipids, nucleic acids, and proteins. Oxidative stress has recently been implicated in depression and anxiety-related disorders. Furthermore, the manifestation of anxiety in numerous psychiatric disorders, such as generalized anxiety disorder, depressive disorder, panic disorder, phobia, obsessive-compulsive disorder, and posttraumatic stress disorder, highlights the importance of studying the underlying biology of these disorders to gain a better understanding of the disease and to identify common biomarkers for these disorders. Most recently, the expression of glutathione reductase 1 and glyoxalase 1, which are genes involved in antioxidative metabolism, were reported to be correlated with anxiety-related phenotypes. This review focuses on direct and indirect evidence of the potential involvement of oxidative stress in the genesis of anxiety and discusses different opinions that exist in this field. Antioxidant therapeutic strategies are also discussed, highlighting the importance of oxidative stress in the etiology, incidence, progression, and prevention of psychiatric disorders.

Induction of apoptosis in human multiple myeloma cell lines by ebselen via enhancing the endogenous reactive oxygen species production

Ebselen a selenoorganic compound showing glutathione peroxidase like activity is an anti-inflammatory and antioxidative agent. Its cytoprotective activity has been investigated in recent years. However, experimental evidence also shows that ebselen causes cell death in several cancer cell types whose mechanism has not yet been elucidated. In this study, we examined the effect of ebselen on multiple myeloma (MM) cell lines in vitro. The results showed that ebselen significantly enhanced the production of reactive oxygen species (ROS) accompanied by cell viability decrease and apoptosis rate increase. Further studies revealed that ebselen can induce Bax redistribution from the cytosol to mitochondria leading to mitochondrial membrane potential ΔΨm changes and cytochrome C release from the mitochondria to cytosol. Furtherly, we found that exogenous addition of N-acetyl cysteine (NAC) completely diminished the cell damage induced by ebselen. This result suggests that relatively high concentration of ebselen can induce MM cells apoptosis in culture by enhancing the production of endogenous ROS and triggering mitochondria mediated apoptotic pathway.

Oxidative stress, redox signaling, and metal chelation in anthracycline cardiotoxicity and pharmacological cardioprotection

SIGNIFICANCE

Anthracyclines (doxorubicin, daunorubicin, or epirubicin) rank among the most effective anticancer drugs, but their clinical usefulness is hampered by the risk of cardiotoxicity. The most feared are the chronic forms of cardiotoxicity, characterized by irreversible cardiac damage and congestive heart failure. Although the pathogenesis of anthracycline cardiotoxicity seems to be complex, the pivotal role has been traditionally attributed to the iron-mediated formation of reactive oxygen species (ROS). In clinics, the bisdioxopiperazine agent dexrazoxane (ICRF-187) reduces the risk of anthracycline cardiotoxicity without a significant effect on response to chemotherapy. The prevailing concept describes dexrazoxane as a prodrug undergoing bioactivation to an iron-chelating agent ADR-925, which may inhibit anthracycline-induced ROS formation and oxidative damage to cardiomyocytes.

RECENT ADVANCES

A considerable body of evidence points to mitochondria as the key targets for anthracycline cardiotoxicity, and therefore it could be also crucial for effective cardioprotection. Numerous antioxidants and several iron chelators have been tested in vitro and in vivo with variable outcomes. None of these compounds have matched or even surpassed the effectiveness of dexrazoxane in chronic anthracycline cardiotoxicity settings, despite being stronger chelators and/or antioxidants.

CRITICAL ISSUES

The interpretation of many findings is complicated by the heterogeneity of experimental models and frequent employment of acute high-dose treatments with limited translatability to clinical practice.

FUTURE DIRECTIONS

Dexrazoxane may be the key to the enigma of anthracycline cardiotoxicity, and therefore it warrants further investigation, including the search for alternative/complementary modes of cardioprotective action beyond simple iron chelation.

Protection against adriamycin-induced cardiomyopathy by carnosine in rats: role of endogenous antioxidants

The aim of this study was to investigate the effects of carnosine, a biological antioxidant, on the acute cardiac damage induced by a single dose of adriamycin in rats. The experimental design consisted of four groups: Control (saline, i.p.); carnosine (CAR; 10 mg/kg/day, i.p.); adriamycin (ADR; 16 mg/kg on the 14th day, i.p.); carnosine with adriamycin. Carnosine was given 2 weeks before and following adriamycin treatment. Blood samples were collected for analysis of plasma creatine kinase (CK) and plasma antioxidant enzymes, glutathione peroxidase (GSH-Px), Cu, Zn-superoxide dismutase (SOD), and catalase (CAT). The rats were then sacrificed, and the hearts were autopsied for hemodynamic study, ECG, and histopathological examination. Results showed that adriamycin produced evident cardiac damage revealed by hemodynamic change, histological alterations, decreased plasma antioxidant enzymes activities, and increased lipid peroxidation to the control value. Carnosine treatment led to significant attenuation of adriamycin-induced cardiomyopathy revealed by normalization of the LVDP, ST interval, CK, SOD, GSH-Px, CAT, and lipid peroxidation. An increase in oxidative stress and inactivation of SOD, GSH-Px, CAT by a single dose of adriamycin were prevented when carnosine was given 2 weeks before and on the same day adriamycin treatment was administered.

Multiple aberrations in shared inflammatory and oxidative & nitrosative stress (IO&NS) pathways explain the co-association of depression and cardiovascular disorder (CVD), and the increased risk for CVD and due mortality in depressed patients

There is evidence that there is a bidirectional relationship between major depression and cardiovascular disorder (CVD): depressed patients are a population at risk for increased cardiac morbidity and mortality, and depression is more frequent in patients who suffer from CVD. There is also evidence that inflammatory and oxidative and nitrosative stress (IO&NS) pathways underpin the common pathophysiology of both CVD and major depression. Activation of these pathways may increase risk for both disorders and contribute to shared risk. The shared IO&NS pathways that may contribute to CVD and depression comprise the following: increased levels of pro-inflammatory cytokines, like interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-12, tumor necrosis factor-α, and interferon-γ; T cell activation; increased acute phase proteins, like C-reactive protein, haptoglobin, fibrinogen and α1-antitrypsin; complement factors; increased LPS load through bacterial translocation and subsequent gut-derived inflammation; induction of indoleamine 2,3-dioxygenase with increased levels of tryptophan catabolites; decreased levels of antioxidants, like coenzyme Q10, zinc, vitamin E, glutathione and glutathione peroxidase; increased O&NS characterized by oxidative damage to low density lipoprotein (LDL) and phospholipid inositol, increased malondialdehyde, and damage to DNA and mitochondria; increased nitrosative stress; and decreased ω3 polyunsaturated fatty acids (PUFAs). The complex interplay between the abovementioned IO&NS pathways in depression results in pro-atherogenic effects and should be regarded as a risk factor to future clinical CVD and due mortality. We suggest that major depression should be added as a risk factor to the Charlson "comorbidity" index. It is advised that patients with (sub)chronic or recurrent major depression should routinely be assessed by serology tests to predict if they have an increased risk to cardiovascular disorders.

Alleviation of doxorubicin-induced toxicities by anthocyanin-rich bilberry (Vaccinium myrtillus L.) extract in rats and mice

The objective of this study was to investigate the effects of anthocyanin-rich bilberry extract (BE) with highly antioxidative potential against doxorubicin (Dox)-induced toxicity in rat and mouse models. Sprague-Dawley rats treated with Dox (15 mg/kg intraperitoneally) showed marked body weight loss, increased abdominal ascites and serum glutamate oxaloacetate transaminase (GOT) level, serum and cardiac lipid peroxidation, myocardial histopathological damage, and depletion of cardiac glutathione (GSH). Dietary supplementation with 1% BE significantly reduced serum lipid peroxidation and increased cardiac creatine phosphokinase activity and total GSH level compared with the levels in the Dox control rats (P < 0.05). Serum GOT and cardiac lipid peroxide levels did not change significantly after BE treatment. Morphologic examination revealed that Dox-induced myocardial damage was also significantly suppressed in rats fed with the 1% BE diet. Oral administration of 500 mg/kg of BE for 10 days to mice treated with Dox (10 mg/kg) partially restored the Dox-induced changes by increasing red blood cell and bone marrow cell counts, and hemoglobin level. Although the protective effects of BE were insufficient to completely counteract the toxic effects of Dox, these results suggest that BE supplementation provides moderate protection against Dox-induced cardiac and hematopoietic damage.

Erdosteine and ebselen as useful agents in intestinal ischemia/reperfusion injury

BACKGROUND

Reactive oxygen and nitrogen species generated during reperfusion of the tissue are characteristic of ischemia/reperfusion (I/R) injury. The purpose of the present study was to investigate whether erdosteine and ebselen, molecules with antioxidant properties and peroxynitrite scavenging capability, respectively, can reduce oxidative stress and histological damage in the rat small bowel subjected to mesenteric I/R injury.

MATERIALS AND METHODS

Forty Sprague-Dawley rats were divided into five groups equally: sham, I/R, I/R plus erdosteine, I/R plus ebselen, and I/R plus erdosteine and ebselen. Intestinal ischemia for 45 min and reperfusion for 3 d were carried out. Ileal specimens were obtained to determine the tissue levels of malondialdehide (MDA), protein carbonyl content (PCC), superoxide dismutase (SOD), glutathione peroxidase (GPx), nitrite/nitrate (NO(x)) level and histological changes.

RESULTS

Intestinal I/R resulted in increased tissue MDA, PCC, and NO(x) levels and decreased SOD and GPx activities. Both erdosteine and ebselen alone significantly decreased MDA, PCC, and NO(x) levels and increased antioxidant enzymes activities, but all values were different from control. These changes almost returned to control values in the group treated with erdostein and ebselen. Histopathologically, the intestinal injury in rats treated with erdosteine and ebselen as well as combination were less than I/R group.

CONCLUSIONS

Both erdosteine and ebselen were able to attenuate I/R injury of the intestine via inhibition of lipid peroxidation and protein oxidation, maintenance of antioxidant, and free radical scavenger properties. Nevertheless, combination treatment showed more promising results, suggesting that scavenging peroxynitrite nearby antioxidant activity is important in preventing intestinal I/R injury.

Ebselen increases cytosolic free Ca2+ concentration, stimulates glutamate release and increases GFAP content in rat hippocampal astrocytes

We have investigated the effect of the seleno-organic compound and radical scavenger ebselen on rat hippocampal astrocytes in culture. Throughout our study we carried out determinations of [Ca2+](c) in fura-2-loaded cells by single cell imaging, glutamate secretion employing an enzymatic-based assay and GFAP expression, which was monitorized by immunocytochemistry and confocal microscopy. Our results show that ebselen (1-20microM) dose dependently increases [Ca2+](c), stimulates glutamate release and increases GFAP content, a hallmark of astrocyte reactivity. Ebselen did not alter significantly cell viability as assayed by determination of LDH release into the extracellular medium. Ebselen-evoked glutamate release and increase in GFAP content were Ca2+-dependent, because incubation of astrocytes in the absence of extracellular Ca2+ (medium containing 0.5mM EGTA) and in the presence of the intracellular Ca2+ chelator BAPTA (10microM) significantly reduced ebselen-evoked changes in these parameters. The effects of ebselen we have observed may underline various signalling pathways which are important for cell proliferation, differentiation and function. However, aberrations in astroglial physiology could significantly compromise brain function, due to their role as modulators of neuron activity. Therefore, we consider that careful attention should be paid when employing ebselen as a prophylactic agent against brain damage.