Cardioprotective effect of metformin against doxorubicin cardiotoxicity in rats

Dapagliflozin Pretreatment Prevents Cardiac Electrophysiological Changes in a Diet and Streptozotocin Induction of Type 2 Diabetes in Rats: A Potential New First-Line?

Purpose

Dapagliflozin exerts cardioprotective effects in Type 2 Diabetes Mellitus (T2DM). However, whether these effects prevent electrocardiographic changes associated with T2DM altogether remain unknown. Our aim was to investigate the prophylactic effect of dapagliflozin pretreatment on the rat ECG using a high-fat, high-fructose (HFHf) diet and a low dose streptozotocin (STZ) model of T2DM.

Methods

Twenty-five (25) rats were randomized into five (5) groups: normal control receiving a normal diet while the other groups received an 8-week HFHf and 40mg/kg STZ on day 42, and either: saline for the diabetic control (1 mg/kg/d), low dose (1.0 mg/kg/d) and high dose dapagliflozin (1.6 mg/kg/d), or metformin (250 mg/kg/d). Oral glucose tolerance (OGT), electrocardiograms (ECGs), paracardial adipose mass, and left ventricular fibrosis were determined. Data were analyzed using GraphPad version 9.0.0.121, with the level of significance at p < 0.05.

Results

Compared to the diabetic control group, a high dose of dapagliflozin preserved the OGT (p = 0.0001), QRS-duration (p = 0.0263), QT-interval (p = 0.0399), and QTc intervals (p = 0.0463). Furthermore, the high dose dapagliflozin group had the lowest paracardial adipose mass (p = 0.0104) and fibrotic area (p = 0.0001). In contrast, while metformin showed favorable effects on OGT (p = 0.0025), paracardial adiposity (p = 0.0153) and ventricular fibrosis (p = 0.0291), it did not demonstrate significant antiarrhythmic effects.

Conclusion

Pretreatment with higher doses of Dapagliflozin exhibits prophylactic cardioprotective characteristics against diabetic cardiomyopathy that include antifibrotic and antiarrhythmic qualities. This suggests that higher doses of dapagliflozin could be a more effective initial therapeutic option in T2DM.

Synergistic effect of metformin and doxorubicin on the metastatic potential of T24 cells

BACKGROUND

The motor ability of cancer cells to cross the basement membrane contributes to their implantation in a new location. Metastasis is a significant factor that worsens the prognosis of cancer patients. Thus, reducing cell invasiveness is an important aspect of anticancer therapy, also in bladder cancer treatment.

MATERIAL

The study material was the T24 cell line of human urinary bladder cancer. The migratory potential of the cells and the effect of the treatment with individually doses and synergistic combination of doxorubicin and metformin in the 500:1 ratio for 24 h were analyzed.

RESULTS

The results obtained show a compound-initiated decrease in the motor abilities of bladder cancer cells compared to controls. A decrease in the rate of colony formation was observed, as well as inhibition of migration through inserts. The visualized reorganization of the vimentin and actin networks confirms the drug-initiated limitation of the metastatic potential of T24 cells.

CONCLUSION

According to our knowledge, we are the first to show, that combination of doxorubicin and metformin also worth considering in the treatment of bladder cancer. We showed that simultaneous administration of these cytostatic enhances the antiproliferative effect of drugs, but also limits cells' migratory potential.

Modeling Doxorubicin-Induced Cardiomyopathy With Fibrotic Myocardial Damage in Wistar Rats

Background

Cardiovascular complications, arising after anthracycline chemotherapy, cause a significant deterioration in the life quality and expectancy of those patients who were previously successfully treated for malignant neoplasms. A number of clinical studies have demonstrated that patients with cardiotoxicity manifested during anthracyclines therapy also have extensive fibrotic changes in the cardiac muscle in the long term. Given the lack of an unambiguous understanding of the mechanisms of fibrotic changes formation under doxorubicin treatment in the myocardium, there is the obvious necessity to create a relevant experimental model of chronic doxorubicin-induced cardiomyopathy with fibrotic myocardial lesions and delayed development of diastolic dysfunction.

Methods

The study was divided into two stages: first stage (creation of acute doxorubicin cardiomyopathy) - 35 male Wistar rats; second stage (creation of chronic doxorubicin cardiomyopathy) - 40 male Wistar rats. The animals were split into eight groups (two control ones and six experimental ones), which determined the doxorubicin dose (first stage: 25, 20.4, 15 mg/kg; second stage: 5, 10, 15 mg/kg, intraperitoneally) and the frequency of injection. Echocardiographic, hematological, histological, and molecular methods were used to confirm the successful modeling of acute and chronic doxorubicin-induced cardiomyopathy with fibrotic lesions.

Results

A model of administration six times every other day with a cumulative dose of doxorubicin 20 mg/kg is suitable for evaluation of acute cardiotoxicity. The 15 mg/kg doxorubicin dose is highly cardiotoxic; what's more, it correlates with progressive deterioration of the clinical condition of the animals after 2 months. The optimal cumulative dose of doxorubicin leads to clinical manifestations confirmed by echocardiographic, histological, molecular changes associated with the development of chronic doxorubicin-induced cardiomyopathy with fibrotic lesions of the left ventricular of the cardiac muscle and ensure long-term survival of animals is 10 mg/kg doxorubicin. A dose of 5 mg/kg of the doxorubicin does not ensure the development of fibrous changes formation.

Conclusion

We assume that cumulative dose of 10 mg/kg with a frequency of administration of six times in 2 days can be used to study the mechanisms of anthracycline cardiomyopathy development.

Cariporide Attenuates Doxorubicin-Induced Cardiotoxicity in Rats by Inhibiting Oxidative Stress, Inflammation and Apoptosis Partly Through Regulation of Akt/GSK-3β and Sirt1 Signaling Pathway

Background: Doxorubicin (DOX) is a potent chemotherapeutic agent with limited usage due to its cumulative cardiotoxicity. The Na⁺/H⁺ exchanger isoform 1 (NHE1) is a known regulator of oxidative stress, inflammation, and apoptosis. The present study was designed to investigate the possible protective effect of cariporide (CAR), a selective inhibitor of NHE1, against DOX-induced cardiotoxicity in rats.

Methods: Male Sprague-Dawley rats were intraperitoneally injected with DOX to induce cardiac toxicity and CAR was given orally for treatment. The injured H9c2 cell model was established by incubation with DOX in vitro. Echocardiography, as well as morphological and ultra-structural examination were performed to evaluate cardiac function and histopathological changes. The biochemical parameters were determined according to the manufacturer’s guideline of kits. ROS were assessed by using an immunofluorescence assay. The serum levels and mRNA expressions of inflammatory cytokines were measured by using ELISA or qRT-PCR. Cardiac cell apoptosis and H9c2 cell viability were tested by TUNEL or MTT method respectively. The protein expressions of Cleaved-Caspase-3, Bcl-2, Bax, Akt, GSK-3β, and Sirt1 were detected by western blot.

Results: Treatment with CAR protected against DOX-induced body weight changes, impairment of heart function, leakage of cardiac enzymes, and heart histopathological damage. In addition, CAR significantly attenuated oxidative stress and inhibited the levels and mRNA expressions of inflammatory cytokines (TNF-α, IL-6, IL-18, and IL-1β), which were increased by DOX treatment. Moreover, CAR significantly suppressed myocardial apoptosis and Cleaved-Caspase-3 protein expression induced by DOX, which was in agreement with the increased Bcl-2/Bax ratio. Also, DOX suppressed phosphorylation of Akt and GSK-3β, which was significantly reversed by administration of CAR. Furthermore, CAR treatment prevented DOX-induced down-regulation of Sirt1 at the protein level in vitro and in vivo. Finally, Sirt1 inhibitor reversed the protective effects of CAR, as evidenced by reduced cell viability and Sirt1 protein expression in vitro.

Conclusion: Taken together, we provide evidence for the first time in the current study that CAR exerts potent protective effects against DOX-induced cardiotoxicity in rats. This cardio-protective effect is attributed to suppressing oxidative stress, inflammation, and apoptosis, at least in part, through regulation of Akt/GSK-3β and Sirt1 signaling pathway, which has not been reported to date.

Cancer Therapy-Induced Cardiotoxicity-A Metabolic Perspective on Pathogenesis, Diagnosis and Therapy

Long-term cardiovascular complications of cancer therapy are becoming ever more prevalent due to increased numbers of cancer survivors. Cancer therapy-induced cardiotoxicity (CTIC) is an incompletely understood consequence of various chemotherapies, targeted anti-cancer agents and radiation therapy. It is typically detected clinically by a reduction in cardiac left ventricular ejection fraction, assessed by echocardiography. However, once cardiac functional decline is apparent, this indicates irreversible cardiac damage, highlighting a need for the development of diagnostics which can detect CTIC prior to the onset of functional decline. There is increasing evidence to suggest that pathological alterations to cardiac metabolism play a crucial role in the development of CTIC. This review discusses the metabolic alterations and mechanisms which occur in the development of CTIC, with a focus on doxorubicin, trastuzumab, imatinib, ponatinib, sunitinib and radiotherapy. Potential methods to diagnose and predict CTIC prior to functional cardiac decline in the clinic are evaluated, with a view to both biomarker and imaging-based approaches. Finally, the therapeutic potential of therapies which manipulate cardiac metabolism in the context of adjuvant cardioprotection against CTIC is examined. Together, an integrated view of the role of metabolism in pathogenesis, diagnosis and treatment is presented.

Targeting Oxidative Stress, NLRP3 Inflammasome, and Autophagy by Fraxetin to Combat Doxorubicin-Induced Cardiotoxicity

Doxorubicin belongs to the class of anthracycline antibiotics that is widely used in the treatment protocols of a wide range of malignancies. The major deleterious effect of doxorubicin use is the possible occurrence of cardiotoxicity. This study aimed to delineate the possible effects of targeting oxidative stress, NLRP3 inflammasome, and autophagy by fraxetin on doxorubicin-induced cardiac dysfunction in rats. In a model of doxorubicin-induced cardiotoxicity, the effects of different doses of fraxetin were assessed by determination of biochemical, histopathological, immunohistochemical, and electron microscopic changes. Fraxetin, in a dose-dependent manner, was found to have the ability to mitigate the harmful effects of oxidative stress and inflammation on myocardial muscles with significant decrease in NLRP3 inflammasome, augmentation of autophagy, and amelioration of the apoptotic signaling pathways. In addition, fraxetin, in a dose-dependent manner, had the ability to combat the echocardiographic, histopathological, immunohistochemical, and electron microscopic changes induced by doxorubicin in cardiomyocytes. As a result, fraxetin may be put into consideration as a new adjuvant line of therapy on the way to mitigate doxorubicin-induced cardiotoxicity.

Protective Role of Vitamin B1 in Doxorubicin-Induced Cardiotoxicity in Rats: Focus on Hemodynamic, Redox, and Apoptotic Markers in Heart

Up until now, the specific mechanisms involved in doxorubicin (DOX)-induced cardiotoxicity have not been fully elucidated. Since thiamine deficiency is associated with myocardial dysfunction and it may lead to cardiomyopathy, we aimed to investigate whether thiamine (Vitamin B₁) treatment provides cardioprotection and modulates DOX mediated subchronic cardiotoxicity as well as to determine possible mechanisms of its effects. The study involved 48 Wistar albino rats divided into four groups: healthy non-treated rats and healthy rats treated with thiamine and DOX rats without treatment and DOX rats treated with thiamine. DOX was applied as a single i.p.injection (15mg/kg), while thiamine treatment lasted 7days (25mg/kg/dayi.p.). Before and after the treatment hemodynamic changes were monitored in vivo by echocardiography. When the protocol was completed, animals were sacrificed and rat hearts were isolated in order to evaluate parameters of cardiac oxidative stress [superoxide anion radical-O₂ ^-, hydrogen peroxide-H₂O₂, nitric oxide-NO^-, index of lipid peroxidation-thiobarbituric acid (TBA) reactive substances (TBARS), superoxide dismutase - SOD, catalase (CAT), and reduced glutathione-GSH] and apoptosis (Bax, Bcl-2, caspases). DOX treatment significantly reduced the ejection fraction, while thiamine treatment led to its minor increase in the DOX-treated group. In that sense, heart oxidative stress markers were significantly increased in DOX-treated rats, while therapeutic dose of thiamine decreased the levels of free radicals. Our study demonstrated the promising ameliorative effects of thiamine against DOX-induced cardiotoxicity through modulation of oxidative stress, suppression of apoptosis, and possibility to improve myocardial performance and morphometric structure of rats` hearts.

Metformin attenuates angiotensin II-induced cardiomyocyte hypertrophy by upregulating the MuRF1 and MAFbx pathway

Pathological cardiac hypertrophy induced by aging and neurohumoral activation, such as angiotensin II (Ang II) activation, is an independent risk factor for heart failure. The muscle really interesting new gene-finger protein-1 (MuRF1) and muscle atrophy F-box (MAFbx) pathway has been previously reported to be an important mechanism underlying the pathogenesis of cardiac hypertrophy. Metformin is currently the first-line blood glucose-lowering agent that can be useful for the treatment of cardiovascular diseases. However, the potential role of metformin in the modulation of MuRF1 and MAFbx in cardiomyocyte hypertrophy remains poorly understood. The present study used H9c2 cells, a cardiomyocyte cell model. The surface area of cultured rat H9c2 myoblasts was measured and the expression levels of MuRF1 and MAFbx were quantified using western blot or reverse transcription-quantitative PCR. H9c2 cells were transfected with MuRF1 and MAFbx small interfering (si) RNA. The present study revealed that Ang II treatment significantly increased the cell surface area of model cardiomyocytes. Additionally, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNA and protein expression was increased following this treatment. Ang II also downregulated MuRF1 and MAFbx protein and mRNA expression. In the H9C2, treatment with metformin attenuated hypertrophic remodeling. In addition, expression of ANP and BNP was significantly reduced in metformin-treated H9C2 cells. The results indicated that metformin increased the activity of MuRF1 and MAFbx and upregulated their expression, the knockdown of which resulted in deteriorative Ang II-induced cell hypertrophy, even following treatment with metformin. Taken together, data from the present study suggest that metformin can prevent cardiac hypertrophy through the MuRF1 and MAFbx pathways.

Exercise, but Not Metformin Prevents Loss of Muscle Function Due to Doxorubicin in Mice Using an In Situ Method

Though effective in treating various types of cancer, the chemotherapeutic doxorubicin (DOX) is associated with skeletal muscle wasting and fatigue. The purpose of this study was to assess muscle function in situ following DOX administration in mice. Furthermore, pre-treatments with exercise (EX) or metformin (MET) were used in an attempt to preserve muscle function following DOX. Mice were assigned to the following groups: control, DOX, DOX + EX, or DOX + MET, and were given a single injection of DOX (15 mg/kg) or saline 3 days prior to sacrifice. Preceding the DOX injection, DOX + EX mice performed 60 min/day of running for 5 days, while DOX + MET mice received 5 daily oral doses of 500 mg/kg MET. Gastrocnemius–plantaris–soleus complex function was assessed in situ via direct stimulation of the sciatic nerve. DOX treatment increased time to half-relaxation following contractions, indicating impaired recovery (p < 0.05). Interestingly, EX prevented any increase in half-relaxation time, while MET did not. An impaired relaxation rate was associated with a reduction in SERCA1 protein content (p = 0.07) and AMPK phosphorylation (p < 0.05). There were no differences between groups in force production or mitochondrial respiration. These results suggest that EX, but not MET may be an effective strategy for the prevention of muscle fatigue following DOX administration in mice.

Cinnamomum zeylanicum Blume (Ceylon cinnamon) bark extract attenuates doxorubicin induced cardiotoxicity in Wistar rats

Anti-tumour efficacy of doxorubicin is hindered by the cumulative dose-dependent cardiotoxicity induced by reactive oxygen species during its metabolism. As Cinnamomum zeylanicum has proven antioxidant potential, objective of this study was to investigate the cardioprotective activity of Cinnamomum bark extract against doxorubicin induced cardiotoxicity in Wistar rats. Physicochemical and phytochemical analysis was carried out and dose response effect and the cardioprotective activity of Cinnamomum were determined in vivo. 180 mg/kg dexrazoxane was used as the positive control. Plant extracts were free of heavy metals and toxic phytoconstituents. In vivo study carried out in Wistar rats revealed a significant increase (p < 0.05) in cardiac troponin I, NT-pro brain natriuretic peptide, AST and LDH concentrations in the doxorubicin control group (18 mg/kg) compared to the normal control. Rats pre-treated with the optimum dosage of Cinnmamomum (2.0 g/kg) showed a significant reduction (p < 0.05) in all above parameters compared to the doxorubicin control. A significant reduction was observed in the total antioxidant capacity, reduced glutathione, glutathione peroxidase, glutathione reductase, superoxide dismutase and catalase activity while the lipid peroxidation and myeloperoxidase activity were significantly increased in the doxorubicin control group compared to the normal control (p < 0.05). Pre-treatment with Cinnamomum bark showed a significant decrease in lipid peroxidation, myeloperoxidase activity and significant increase in rest of the parameters compared to the doxorubicin control (p < 0.05). Histopathological analysis revealed a preserved appearance of the myocardium and lesser degree of cellular changes of necrosis in rats pre-treated with Cinnamomum extract. In conclusion, Cinnamomum bark extract has the potential to significantly reduce doxorubicin induced oxidative stress and inflammation in Wistar rats.

Date Palm Pollen Extract Avert Doxorubicin-Induced Cardiomyopathy Fibrosis and Associated Oxidative/Nitrosative Stress, Inflammatory Cascade, and Apoptosis-Targeting Bax/Bcl-2 and Caspase-3 Signaling Pathways

Simple Summary

The use of date palm pollen ethanolic extract (DPPE) is a conventional approach in improving the side-effects induced by Doxorubicin (DOX).DPPE mitigated DOX-induced body and heart weight changes and ameliorated DOX-induced elevated cardiac injury markers. In addition, serum cardiac troponin I concentrations (cTnI), troponin T (cTnT), and N-terminal NBP and cytosolic (Ca⁺²) were amplified by alleviating the inflammatory and oxidative injury markers and decreasing histopathological lesions severity. DPPE decreased DOX-induced heart injuries by mitigating inflammation, fibrosis, and apoptosis through its antioxidant effect. To reduce DOX-induced oxidative stress injuries and other detrimental effects, a combined treatment of DPPE is advocated.

Abstract

Doxorubicin (DOX) has a potent antineoplastic efficacy and is considered a cornerstone of chemotherapy. However, it causes several dose-dependent cardiotoxic results, which has substantially restricted its clinical application. This study was intended to explore the potential ameliorative effect of date palm pollen ethanolic extract (DPPE) against DOX-induced cardiotoxicity and the mechanisms underlying it. Forty male Wistar albino rats were equally allocated into Control (CTR), DPPE (500 mg/kg bw for 4 weeks), DOX (2.5 mg/kg bw, intraperitoneally six times over 2 weeks), and DPPE + DOX-treated groups. Pre-coadministration of DPPE with DOX partially ameliorated DOX-induced cardiotoxicity as DPPE improved DOX-induced body and heart weight changes and mitigated the elevated cardiac injury markers activities of serum aminotransferases, lactate dehydrogenase, creatine kinase, and creatine kinase-cardiac type isoenzyme. Additionally, the concentration of serum cardiac troponin I (cTnI), troponin T (cTnT), N-terminal pro-brain natriuretic peptide (NT-pro BNP), and cytosolic calcium (Ca⁺²) were amplified. DPPE also alleviated nitrosative status (nitric oxide) in DOX-treated animals, lipid peroxidation and antioxidant molecules as glutathione content, and glutathione peroxidase, catalase, and superoxide dismutase activities and inflammatory markers levels; NF-κB p65, TNF-α, IL-1β, and IL-6. As well, it ameliorated the severity of histopathological lesions, histomorphometric alteration and improved the immune-staining of the pro-fibrotic (TGF-β1), pro-apoptotic (caspase-3 and Bax), and anti-apoptotic (Bcl-2) proteins in cardiac tissues. Collectively, pre-coadministration of DPPE partially mitigated DOX-induced cardiac injuries via its antioxidant, anti-inflammatory, anti-fibrotic, and anti-apoptotic potential.

What is considered cardiotoxicity of anthracyclines in animal studies

Anthracyclines are commonly used anticancer drugs with well-known and extensively studied cardiotoxic effects in humans. In the clinical setting guidelines for assessing cardiotoxicity are well-established with important therapeutic implications. Cardiotoxicity in terms of impairment of cardiac function is largely diagnosed by echocardiography and based on objective metrics of cardiac function. Until this day, cardiotoxicity is not an endpoint in the current general toxicology and safety pharmacology preclinical studies, although other classes of drugs apart from anthracyclines, along with everyday chemicals have been shown to manifest cardiotoxic properties. Also, in the relevant literature there are not well-established objective criteria or reference values in order to uniformly characterize cardiotoxic adverse effects in animal models. This in depth review focuses on the evaluation of two important echocardiographic indices, namely ejection fraction and fractional shortening, in the literature concerning anthracycline administration to rats as the reference laboratory animal model. The analysis of the gathered data gives promising results and solid prospects for both, defining anthracycline cardiotoxicity objective values and delineating the guidelines for assessing cardiotoxicity as a separate hazard class in animal preclinical studies for regulatory purposes.

Luteolin attenuates doxorubicin-induced cardiotoxicity by modulating the PHLPP1/AKT/Bcl-2 signalling pathway

Background

Luteolin (LUT) is a flavonoid found in vegetables and fruits that has diverse functions. Doxorubicin (DOX) is an anthracycline antibiotic that is frequently used for the treatment of various cancers. Unfortunately, the clinical efficacy of DOX is limited by its dose-related cardiotoxicity. In this study, we aimed to investigate the potential mechanism through which LUT attenuates cardiotoxicity in vivo.

Methods

We evaluated the body weight, heart weight, electrocardiogram, and pathological changes before and after administration of LUT. Moreover, the effects of LUT (50 mg/kg in the low dose group, 100 mg/kg in the high dose group) on biochemical parameters (brain natriuretic peptide, creatine kinase MB, cardiac troponin T, and dehydrogenation of lactate enzyme) and oxidative stress parameters (malondialdehyde and superoxide dismutase) were studied in the sera of cardiotoxicity model rats. We also identified the apoptotic mediators whose expression was induced by LUT by quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR) evaluation. In addition, we used network analysis to predict DOX-induced cardiotoxicity and protection afforded by LUT. Western blotting was used to detect the expression of associated proteins.

Results

LUT significantly improved DOX-induced cardiotoxicity in a dose-dependent fashion. LUT ameliorated DOX-induced weight loss and heart weight changes, as well as changes in biochemical parameters and oxidative stress parameters in heart injury model rats. LUT’s protective effect was observed via regulation of the apoptotic markers Bcl-2, Bax, and caspase-3 mRNA and protein expression levels. Network analysis showed that the AKT/Bcl-2 signalling pathway was activated; specifically, the PH domain leucine-rich repeats protein phosphatase 1 (phlpp1) was involved in the AKT/Bcl-2 signal pathway. LUT inhibited the activity of phlpp1 leading to positive regulation of the AKT/Bcl-2 pathway, which attenuated doxorubicin-induced cardiotoxicity.

Conclusions

These results demonstrate that LUT exerted protective effects against DOX-induced cardiotoxicity in vivo by alleviating oxidative stress, suppressing phlpp1 activity, and activating the AKT/Bcl-2 signalling pathway.

Effects of doxorubicin-induced cardiotoxicity on cardiac mitochondrial dynamics and mitochondrial function: Insights for future interventions

Anthracyclines is an effective chemotherapeutic treatment used for many types of cancer. However, high cumulative dosage of anthracyclines leads to cardiac toxicity and heart failure. Dysregulation of mitochondrial dynamics and function are major pathways driving this toxicity. Several pharmacological and non‐pharmacological interventions aiming to attenuate cardiac toxicity by targeting mitochondrial dynamics and function have shown beneficial effects in cell and animal models. However, in clinical practice, there is currently no standard therapy for the prevention of anthracycline‐induced cardiotoxicity. This review summarizes current reports on the impact of anthracyclines on cardiac mitochondrial dynamics and mitochondrial function and potential interventions targeting these pathways. The roles of mitochondrial dynamics and mitochondrial function in the development of anthracycline‐induced cardiotoxicity should provide insights in devising novel strategies to attenuate the cardiac toxicity induced by anthracyclines.

Cardioprotective Potential of Murraya koenigii (L.) Spreng. Leaf Extract against Doxorubicin-Induced Cardiotoxicity in Rats

Dose-dependent cardiotoxicity of doxorubicin may lead to irreversible congestive heart failure. Although multiple mechanisms are involved, generation of free radicals is the most commonly postulated mechanism. Therefore, free radical scavengers are considered as potential therapeutic agents. As Murraya koenigii leaves are a rich source of flavonoids and phenols, they have the ability to scavenge free radicals effectively. Therefore, the objective of this study was to investigate the cardioprotective potential of Murraya leaf extract against doxorubicin-induced cardiotoxicity in rats. Rats were randomly divided into five groups with 10 animals in each group. Doxorubicin was administered intraperitonially at 18 mg/kg while lyophilized plant extract was administered orally at 2 g/kg. Dexrazoxane, at 180 mg/kg, was used as the positive control. Cardiac damage of doxorubicin control was evident with a significant increase (p < 0.05) in cardiac troponin I, NT-pro BNP, AST, and LDH compared to the normal control. Plant-treated group showed cardioprotective effect by significantly reducing (p < 0.05) all of the above parameters compared to doxorubicin control (p < 0.05). Increased oxidative stress in doxorubicin control was evident with a significant reduction in reduced glutathione, glutathione reductase, glutathione peroxidase, total antioxidant capacity, superoxide dismutase, and catalase activity and a significant increase in lipid peroxidation compared to the control. Interestingly, treatment with Murraya leaf extract showed a significant increase in all of the above antioxidant parameters and a significant reduction in lipid peroxidation by showing an antioxidant effect. A significant increase in myeloperoxidase activity confirmed the increased inflammatory activity in doxorubicin control group whereas plant-treated group showed a significant reduction (p < 0.05) which expressed the anti-inflammatory effect of Murraya leaf extract. Doxorubicin-treated group showed histological evidence of extensive damage to the myocardium while plant-treated group showed a preserved myocardium with lesser degree of damage. Pretreatment with Murraya leaf extract may replenish cardiomyocytes with antioxidants and promote the defense against doxorubicin-induced cardiotoxicity.

Metformin as a protective agent against natural or chemical toxicities: a comprehensive review on drug repositioning

BACKGROUND

Metformin is the first prescribed drug for hyperglycemia in type 2 diabetes mellitus. Mainly by activating AMPK pathway, this drug exerts various functions that among them protective effects are of the interest.

PURPOSE

Herein, we aimed to gather data about the protective impacts of metformin against various natural or chemical toxicities.

RESULTS

An extensive search among PubMed, Scopus, and Google Scholar was conducted by keywords related to protection, toxicity, natural and chemical toxins and, metformin. Our literature review showed metformin alongside its anti-hyperglycemic effect has a wide range of anti-toxic effects against anti-tumour and routine drugs, natural and chemical toxins, herbicides and, heavy metals.

CONCLUSION

It is evident that metformin is a potent drug against the toxicity of a broad spectrum of natural, chemical toxic agents which is proved by a vast number of studies. Metformin mainly through AMPK axis can protect different organs against toxicities. Moreover, metformin preserves DNA integrity and can be an option for adjuvant therapy to ameliorate side effect of other therapeutics.

Immune Biomarkers for Diagnosis and Treatment Monitoring of Tuberculosis: Current Developments and Future Prospects

Tuberculosis (TB) treatment monitoring is paramount to clinical decision-making and the host biomarkers appears to play a significant role. The currently available diagnostic technology for TB detection is inadequate. Although GeneXpert detects total DNA present in the sample regardless live or dead bacilli present in clinical samples, all the commercial tests available thus far have low sensitivity. Humoral responses against Mycobacterium tuberculosis (Mtb) antigens are generally low, which precludes the use of serological tests for TB diagnosis, prognosis, and treatment monitoring. Mtb-specific CD4⁺ T cells correlate with Mtb antigen/bacilli burden and hence might serve as good biomarkers for monitoring treatment progress. Omics-based techniques are capable of providing a more holistic picture for disease mechanisms and are more accurate in predicting TB disease outcomes. The current review aims to discuss some of the recent advances on TB biomarkers, particularly host biomarkers that have the potential to diagnose and differentiate active TB and LTBI as well as their use in disease prognosis and treatment monitoring.

Protective effects of olmesartan and l-carnitine on doxorubicin-induced cardiotoxicity in rats

Doxorubicin (DOX), an anthracycline antibiotic, is an important antineoplastic agent due to its high antitumor efficacy in hematological as well as in solid malignancies. The clinical use of DOX is limited due to its cardiotoxic effects. The present study aimed to investigate the possible protective effect of olmesartan (Olm), l-carnitine (L-CA), and their combination in cardiotoxicity induced by DOX in rats. Male albino rats were randomly divided into seven experimental groups (n = 8): group I: normal control, group II: L-CA, group III: Olm, group IV: DOX. The other three groups were treated with Olm (10 mg/kg), L-CA (300 mg/kg), and their combination for 2 weeks after induction of cardiotoxicity by a single dose of DOX (20 mg/kg). In the results, DOX showed a significant elevation in serum troponin I, creatine kinase-MB (CK-MB), and lactate dehydrogenase (LDH) together with increased inflammation manifested by the rise of tumor necrosis factor-alpha (TNF-α), intercellular adhesion molecules-1 (ICAM-1), interleukin IL-1β (IL-1β), myeloperoxidase (MPO), nuclear factor-kappa B (NF-κB), and transforming growth factor beta (TGF-β) in cardiac tissues as well as DOX-induced oxidative stress by increasing in malondialdehyde (MDA) and decreasing in superoxide dismutase (SOD) and glutathione (GSH) in heart tissues. In addition, caspase-3 activity was boosted as indication of increased apoptosis. On the other hand, administration of L-CA and Olm attenuated the DOX-evoked disturbances in the abovementioned parameters. In addition, DOX exhibited echocardiographic changes and severe histopathological changes, which were significantly reversed by L-CA and Olm treatment. In conclusion, the present study data confirm the protective role of L-CA and Olm in DOX-induced cardiotoxicity, which may be related to its antioxidant, antiinflammatory, and antiapoptotic agents.

Metformin as Anti-Aging Therapy: Is It for Everyone?

Metformin is the most widely prescribed oral hypoglycemic medication for type 2 diabetes worldwide. Metformin also retards aging in model organisms and reduces the incidence of aging-related diseases such as neurodegenerative disease and cancer in humans. In spite of its widespread use, the mechanisms by which metformin exerts favorable effects on aging remain largely unknown. Further, not all individuals prescribed metformin derive the same benefit and some develop side effects. Before metformin finds its way to mainstay therapy for anti-aging, a more granular understanding of the effects of the drug in humans is needed. This review provides an overview of recent findings from metformin studies in aging and longevity and discusses the use of metformin to combat aging and aging-related diseases.

Cardioprotective roles of sestrin 1 and sestrin 2 against doxorubicin cardiotoxicity

Doxorubicin is a chemotherapy medication widely used to treat a variety of cancers. Even though it offers one of the most effective anti-cancer treatments, its clinical use is limited because of its strong cardiotoxicity that can lead to fatal conditions. Here, we show that sestrin 1 and sestrin 2, members of the sestrin family of proteins that are stress-inducible regulators of metabolism, are critical for suppressing doxorubicin cardiotoxicity and coordinating the AMPK-mammalian target of rapamycin complex 1 (mTORC1) autophagy signaling network for cardioprotection. Expression of both sestrin 1 and sestrin 2 was highly increased in the mouse heart after doxorubicin injection. Genetic ablation of sestrin 1 and sestrin 2 rendered mice more vulnerable to doxorubicin and exacerbated doxorubicin-induced cardiac pathologies including cardiomyocyte apoptosis and cardiac dysfunction. These pathologies were associated with strong dysregulation of the cardiac signaling network, including suppression of the AMPK pathway and activation of the mTORC1 pathway. Consistent with AMPK downregulation and mTORC1 upregulation, autophagic activity of heart tissue was diminished, leading to prominent accumulation of autophagy substrate, p62/SQSTM1. Taken together, our results indicate that sestrin 1 and sestrin 2 are important cardioprotective proteins that coordinate metabolic signaling pathways and autophagy to minimize cardiac damage in response to doxorubicin insult. Augmenting this protective mechanism could provide a novel therapeutic rationale for prevention and treatment of doxorubicin cardiotoxicity. NEW & NOTEWORTHY Doxorubicin is a highly efficient chemotherapeutic medicine; however, its use is limited because of its strong cardiotoxicity. Here, we show that sestrin 1 and sestrin 2 are critical protectors of cardiomyocytes from doxorubicin damage. By upregulating AMPK and autophagic activities and suppressing mammalian target of rapamycin complex 1 and oxidative stress, sestrins counteract detrimental effects of doxorubicin on cardiomyocytes. Correspondingly, loss of sestrin 1 and sestrin 2 produced remarkable dysregulation of these pathways, leading to prominent cardiac cell death and deterioration of heart function.

Metformin reduces radiation-induced cardiac toxicity risk in patients having breast cancer

To analyze the effects of metformin in reducing radiation-induced cardiac toxicity (RICT) risk during adjuvant radiotherapy (RT) after surgery for early-stage breast cancer women. We compare the consecutive occurrence of major heart events (heart failure and coronary artery disease) in women with early-stage breast cancer receiving adjuvant breast RT with metformin and in those receiving RT without metformin. A retrospective national cohort study was conducted using the Taiwan Cancer Registry of 2004-2014. This study included 6,993 women with early-stage breast cancer who received adjuvant breast RT. Metformin users were defined as patients prescribed metformin for >28 days during adjuvant breast RT. An inverse probability of treatment weighting (IPTW) Cox hazards model was used to estimate metformin effects on the occurrence of major heart events. Among women with breast cancer status post-surgery under adjuvant breast RT, 2,062 were prescribed metformin and 4,931 were not prescribed metformin. Cox proportional hazard regression analysis, with adjustment using IPTW, indicated that metformin use during adjuvant breast RT significantly reduces the risk of major heart events (adjusted hazard ratio [aHR], 0.789; 95% confidence interval [CI], 0.645-0.965; P = 0.021). In another negative control exposure, thiazolidinedione use during adjuvant breast RT did not statistically reduce consecutive RICT risk (aHR, 1.106; 95% CI, 0.768-1.594; P = 0.589). Our results suggest that metformin use during adjuvant breast RT was associated with reduced RICT risk in women with early-stage breast cancer.

Bioinformatics identification of potential candidate blood indicators for doxorubicin-induced heart failure

The care of individual patients requiring anthracyclines remains challenging as uncertainty persists on predictors of cardiotoxicity. The aim of the present study was to identify potential candidate blood indicators of doxorubicin-induced heart failure. The gene expression profiles of GSE40447 and GSE9128 microarray data were downloaded from the Gene Expression Omnibus database to identify differentially expressed genes (DEGs) using the R/Limma package or GEO2R. Functional and pathway enrichment analysis on DEGs were performed using DAVID database. The cardiovascular disease (CVD)-related DEGs were screen out based on the CardioGenBase database. The protein-protein interaction (PPI) network was constructed with STRING database and visualized by using Cytoscape. Then, the CVD-related DEGs were validated by intersection analysis with DEGs in GSE9128. The overlapping DEGs with a consistent expression pattern in GSE40447 and GSE9128 were identified as candidate indicators for doxorubicin-induced heart failure. A total of 516 DEGs potentially associated with doxorubicin-induced heart failure in GSE40447 were identified, which were mainly enriched in the gene ontology terms related to B cells, leukocytes, lymphocyte activation and B cell receptor signaling pathway. Of the DEGs, 42 were screened out as CVD-related DEGs by using CardioGenBase. Seven genes with high connectivity degree were presented in the PPI network. Finally, 5/6 CVD-related DEGs revealed by the intersection analysis were validated by GSE9128 and highlighted as candidate indicators of doxorubicin-induced heart failure: CD163, CD28, SLC25A20, ANPEP and TLR5. Several genes, including the 5 previously mentioned, were proposed as potential candidate blood indicators for doxorubicin-induced heart failure. Further experimental validations are greatly warranted for future clinical application.

The Cardioprotective Effect of Metformin in Doxorubicin-Induced Cardiotoxicity: The Role of Autophagy

The molecular mechanisms underlying doxorubicin-induced cardiotoxicity are still being investigated, but are known to involve oxidative stress, mitochondrial dysfunction, and the dysregulation of autophagy. The objective of the current study was to examine the protective role of metformin and its effect on autophagy in doxorubicin-induced cardiotoxicity. Sprague–Dawley rats were divided into four groups at random. The doxorubicin-treated group received doxorubicin (3 mg/kg every second day) intraperitoneally. The metformin-treated group received 250 mg/kg/day metformin via gavage. The doxorubicin + metformin-treated group received both at the above-mentioned doses. The control group received vehicle only. Following the two-week treatment, the hearts were isolated, and cardiac functions were registered. Serum levels of lactate dehydrogenase (LDH), creatine kinase iso-enzyme MB (CK-MB) enzyme, Troponin T, and cardiac malondialdehyde (MDA) were also measured. Heart tissue samples were histopathologically examined by using Masson’s trichrome staining and Western blot analysis was conducted for evaluating the expression level of AMP-activated protein kinase (AMPK) and autophagy-associated proteins beclin-1, LC3B-II, and p62, respectively. The results revealed that treatment with metformin conferred increased cardiac protection against the development of cardiotoxicity manifested by a significant decrease in serum Troponin T and cardiac MDA levels, and remarkable improvement in heart function in connection with histopathological features. Furthermore, by focusing on the contribution of autophagic proteins, it was found that metformin normalised autophagy, which may help cardiomyocytes survive doxorubicin-induced toxicity. These results promote the use of metformin, which would be a preferable drug for patients receiving doxorubicin.

Protective effect of paracetamol in doxorubicin-induced cardiotoxicity in ischemia/reperfused isolated rat heart

OBJECTIVE

Doxorubicin (DOX) induces cardiac dysfunction. Paracetamol (APAP) has also been established as an effective cardioprotective agent during ischemia/reperfusion. Therefore, this study aims to evaluate the effect of APAP on DOX-induced cardiotoxicity in ischemia/reperfused isolated rat heart.

METHODS

A total of 36 rats were equally divided into four groups: control, DOX (30 min, 20 µM DOX perfusion), APAP (15 min before and after ischemia, 0.35 mM APAP perfusion), and DOX+APAP (perfused with the same protocol in DOX and APAP groups). The isolated hearts were perfused according to the Langendorff method. Cardiac parameters, including left ventricular developed pressure (LVDP), heart rate (HR), coronary flow (CF), and rate pressure product (RPP; LVDP×HR) were measured. Lactate dehydrogenase (LDH) concentration was also assessed.

RESULTS

At the end of the baseline period, the RPP, HR, and CF values were lower in the DOX group than in the control group (p<0.01). Meanwhile, there were no significant differences between the values of cardiac function parameters in the DOX+APAP and control groups. In the reperfusion period, the RPP and CF values were significantly increased in the DOX+APAP group compared with the DOX group (p<0.05). Furthermore, the LDH concentration was decreased in the DOX+APAP group compared with the DOX group.

CONCLUSION

APAP perfusion protected the hearts against DOX-induced cardiotoxicity in the baseline and ischemia/reperfusion conditions. These findings can be explained by the effect of APAP on antioxidant capacity and mitochondrial permeability transition pores.

Metformin promotes the survival of transplanted cardiosphere-derived cells thereby enhancing their therapeutic effect against myocardial infarction

BACKGROUND

Transplantation of cardiosphere-derived cells (CDCs) has been shown to exert a therapeutic effect in patients with myocardial infarction (MI). However, poor survival of transplanted CDCs limits their beneficial effect. Metformin (MET) activates AMP-activated protein kinase (AMPK) which is associated with cell survival. The aim of this study is to determine whether MET improves CDC survival in the transplantation microenvironment and enhances the therapeutic effect of CDC transplantation against MI.

METHODS

CDCs were isolated and expanded from transgenic β-actin-GFP mice. CDCs were pretreated with MET and intramyocardially injected into wild-type C57 mouse heart with MI injury. The survival of CDCs was quantified, and the infarct size and cardiac function of treated hearts were evaluated.

RESULTS

CDC transplantation modestly reduced infarct size and improved cardiac function in the post-MI heart, which was further improved by MET treatment. MET pretreatment significantly increased the survival of CDCs transplanted into the myocardium. MET also reduced CDC apoptosis induced by oxidative stress in vitro. The anti-apoptotic effect of MET was blocked by the AMPK inhibitor compound C. MET increased AMPK phosphorylation and upregulated endothelial nitric oxide synthase (eNOS) in CDCs under oxidative stress, which might be associated with the anti-apoptotic effect of MET.

CONCLUSIONS

MET improves the survival of transplanted CDCs in the myocardium, thereby enhancing their therapeutic effect against MI injury. The pro-survival function of MET on CDCs might be associated with an AMPK-eNOS-dependent mechanism.