Efficacy of Dexrazoxane in Cardiac Protection in Pediatric Patients Treated With Anthracyclines

Therapeutic potential of synthetic and natural iron chelators against ferroptosis

Ferroptosis, a regulated form of cell death, is characterized by iron accumulation that results in the production of reactive oxygen species. This further causes lipid peroxidation and damage to the cellular components, eventually culminating into oxidative stress. Recent studies have highlighted the pivotal role of ferroptosis in the pathophysiological development and progression of various diseases such as β-thalassemia, hemochromatosis, and neurodegenerative disorders like AD and PD. Extensive efforts are in progress to understand the molecular mechanisms governing the role of ferroptosis in these conditions, and chelation therapy stands out as a potential approach to mitigate ferroptosis and its related implications in their development. There are currently both synthetic and natural iron chelators that are being researched for their potential as ferroptosis inhibitors. While synthetic chelators are relatively well-established and studied, their short plasma half-life and toxic side effects necessitate the exploration and identification of natural products that can act as efficient and safe iron chelators. In this review, we comprehensively discuss both synthetic and natural iron chelators as potential therapeutic strategies against ferroptosis-induced pathologies.

Doxorubicin-Induced Cardiac Remodeling: Mechanisms and Mitigation Strategies

BACKGROUND

The therapeutic prowess of doxorubicin in oncology is marred by its cardiotoxic consequences, manifesting as cardiac remodeling. Pathophysiological alterations triggered by doxorubicin include inflammatory cascades, fibrotic tissue deposition, vascular and valvular changes, and finally cardiomyopathy. These multifarious consequences collectively orchestrate the deterioration of cardiac architecture and function.

METHOD

By charting the molecular underpinnings and remedial prospects, this review aspires to contribute a novel perspective using latest publications to the ongoing quest for cardioprotection in cancer therapy.

RESULTS AND DISCUSSION

Experimental analyses demonstrate the pivotal roles of oxidative stress and subsequent necrosis and apoptosis of cardiomyocytes, muscle cells, endothelial cells, and small muscle cells in different parts of the heart. In addition, severe and unusual infiltration of macrophages, mast cells, and neutrophils can amplify oxidative damage and subsequent impacts such as chronic inflammatory responses, vascular and valvular remodeling, and fibrosis. These modifications can render cardiomyopathy, ischemia, heart attack, and other disorders. In an endeavor to counteract these ramifications, a spectrum of emerging adjuvants and strategies are poised to fortify the heart against doxorubicin's deleterious effects.

CONCLUSION

The compendium of mitigation tactics such as innovative pharmacological agents hold the potential to attenuate the cardiotoxic burden.

The Protective Effects of Carvacrol Against Doxorubicin-Induced Cardiotoxicity In Vitro and In Vivo

Doxorubicin (DOX) is a remarkable chemotherapeutic agent, however, its adverse effect on DOX-induced cardiotoxicity (DIC) is a rising concern. Recent research has identified carvacrol (CAR), an antioxidant and anti-inflammatory agent, as a promising natural compound for protecting against DIC. This study aims to investigate the potential cardioprotective effects properties of CAR in vitro and in vivo. The cardioprotective effect of CAR was assessed by pretreating H9c2 cells with non-toxic CAR for 24 h, followed by co-treatment with DOX (10 μM) for an additional 24 h. The cell viability was determined using an MTT assay. For the in vivo study, male Sprague-Dawley rats (200-250 g) were randomly divided into three groups: control, cardiotoxicity (DOX), and treatment (CAR + DOX) groups. CAR (50 mg/kg, BW) was administered orally to the CAR + DOX groups for 14 days. Then, a single dose of DOX (15 mg/kg/i.p, BW) was administered on day 15 for DOX and CAR + DOX groups. The rats were allowed to recover for 3 days before being sacrificed. Our results demonstrated that DOX (10 µM) significantly reduced H9c2 cell viability by 50% (p < 0.0001), and CAR (0.067 µM) protected H9c2 cells from DIC (p = 0.0045). In the rat model, CAR pretreatment effectively mitigated DOX-induced reductions in systolic pressure (p = 0.0007), pulse pressure (p = 0.0213), hypertrophy (p = 0.0049), and cardiac fibrosis (p = 0.0006). However, the pretreatment did not alter the heart function, oxidative stress, and antioxidant enzymes. In conclusion, our results indicate that CAR could potentially serve as an adjuvant to reduce cardiotoxicity by ameliorating myocardial fibrosis and hypertrophy.

Abnormal Global Longitudinal Strain During Anthracycline Treatment Predicts Future Cardiotoxicity in Children

Global longitudinal strain (GLS) is a sensitive predictor of cardiotoxicity in adults with cancer. However, the significance of abnormal GLS during childhood cancer treatment is less well-understood. The objective was to evaluate the use of GLS for predicting later cardiac dysfunction in pediatric cancer survivors exposed to high-dose anthracyclines. This was a retrospective study of pediatric patients exposed to a doxorubicin isotoxic equivalent dose of ≥ 225 mg/m2. Transthoracic echocardiograms (TTE) were obtained prior to chemotherapy (T1), during anthracycline therapy (T2), and following completion of therapy (T3). Cardiotoxicity was defined as meeting at least one of the following criteria after anthracycline therapy: a decrease in left ventricle ejection fraction (LVEF) by 10% from baseline to a value < 55%, fractional shortening < 28%, or a decrease in GLS by ≥ 15% from baseline. Nineteen of 57 (33%) patients met criteria for cardiotoxicity at T3. Cardiotoxicity was associated with a lower LVEF at T2 (p = 0.0003) and a decrease in GLS by ≥ 15% at T2 compared to baseline (p =  < 0.0001). ROC analysis revealed that the best predictor of cardiotoxicity at T3 was the percent change in GLS at T2 compared to baseline (AUC 0.87). A subgroup analysis revealed that a decrease in GLS by ≥ 15% from baseline at 0-6 months from completion of anthracycline therapy was associated with cardiotoxicity > 1-year post-treatment (p = 0.017). A decline in GLS during chemotherapy was the best predictor of cardiotoxicity post-treatment. GLS serves as an important marker of cardiac function in pediatric patients undergoing treatment with anthracyclines.

Serum Carnitine Concentrations and Cardiac Function in Pediatric, Adolescent and Young Adult Oncology Patients Receiving High-Dose Anthracyclines

OBJECTIVE

Anthracycline chemotherapy agents have significant dose-dependent cardiotoxic effects. -Carnitine, a non-essential amino acid, is involved in long chain fatty acid oxidation, and carnitine deficiency can result in cardiomyopathy and cardiac arrhythmias. If administered concurrently with chemotherapy, carnitine supplementation could be a potential strategy to prevent cardiotoxicity. However, the association between serum carnitine concentrations and anthracycline cardiotoxicity during cancer treatment in the childhood, adolescent, and young adult (CAYA) age range has not been established.

METHODS

This prospective pilot cohort study characterized changes in serum carnitine concentrations and cardiac function before, during, and approximately 1 year after large-dose anthracycline therapy in newly diagnosed CAYA cancer patients.

RESULTS

Among 21 patients with a mean cumulative anthracycline dose exposure of 409 mg/m2 of -doxorubicin equivalents, left ventricular ejection fraction and relative wall thickness decreased, indicating an overall decline in cardiac function. A reversible decrease in serum carnitine concentrations was also observed. A non-statistically significant positive correlation was observed; for every 1 mmol/L decrease in serum carnitine concentration, there was a 0.09% decrease in LVEF (p = 0.2).

CONCLUSIONS

These findings from this small pilot study suggest that there may be a relationship between serum carnitine concentrations and cardiac function after anthracycline therapy that should be evaluated in larger studies.

Update on clinical and experimental management of diabetic cardiomyopathy: addressing current and future therapy

Diabetic cardiomyopathy (DCM) is a severe secondary complication of type 2 diabetes mellitus (T2DM) that is diagnosed as a heart disease occurring in the absence of any previous cardiovascular pathology in diabetic patients. Although it is still lacking an exact definition as it combines aspects of both pathologies - T2DM and heart failure, more evidence comes forward that declares DCM as one complex disease that should be treated separately. It is the ambiguous pathological phenotype, symptoms or biomarkers that makes DCM hard to diagnose and screen for its early onset. This re-view provides an updated look on the novel advances in DCM diagnosis and treatment in the experimental and clinical settings. Management of patients with DCM proposes a challenge by itself and we aim to help navigate and advice clinicians with early screening and pharmacotherapy of DCM.

Drug Selection and Posology, Optimal Therapies and Risk/Benefit Assessment in Medicine: The Paradigm of Iron-Chelating Drugs

The design of clinical protocols and the selection of drugs with appropriate posology are critical parameters for therapeutic outcomes. Optimal therapeutic protocols could ideally be designed in all diseases including for millions of patients affected by excess iron deposition (EID) toxicity based on personalised medicine parameters, as well as many variations and limitations. EID is an adverse prognostic factor for all diseases and especially for millions of chronically red-blood-cell-transfused patients. Differences in iron chelation therapy posology cause disappointing results in neurodegenerative diseases at low doses, but lifesaving outcomes in thalassemia major (TM) when using higher doses. In particular, the transformation of TM from a fatal to a chronic disease has been achieved using effective doses of oral deferiprone (L1), which improved compliance and cleared excess toxic iron from the heart associated with increased mortality in TM. Furthermore, effective L1 and L1/deferoxamine combination posology resulted in the complete elimination of EID and the maintenance of normal iron store levels in TM. The selection of effective chelation protocols has been monitored by MRI T2* diagnosis for EID levels in different organs. Millions of other iron-loaded patients with sickle cell anemia, myelodysplasia and haemopoietic stem cell transplantation, or non-iron-loaded categories with EID in different organs could also benefit from such chelation therapy advances. Drawbacks of chelation therapy include drug toxicity in some patients and also the wide use of suboptimal chelation protocols, resulting in ineffective therapies. Drug metabolic effects, and interactions with other metals, drugs and dietary molecules also affected iron chelation therapy. Drug selection and the identification of effective or optimal dose protocols are essential for positive therapeutic outcomes in the use of chelating drugs in TM and other iron-loaded and non-iron-loaded conditions, as well as general iron toxicity.

Iron Load Toxicity in Medicine: From Molecular and Cellular Aspects to Clinical Implications

Iron is essential for all organisms and cells. Diseases of iron imbalance affect billions of patients, including those with iron overload and other forms of iron toxicity. Excess iron load is an adverse prognostic factor for all diseases and can cause serious organ damage and fatalities following chronic red blood cell transfusions in patients of many conditions, including hemoglobinopathies, myelodyspasia, and hematopoietic stem cell transplantation. Similar toxicity of excess body iron load but at a slower rate of disease progression is found in idiopathic haemochromatosis patients. Excess iron deposition in different regions of the brain with suspected toxicity has been identified by MRI T2* and similar methods in many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Based on its role as the major biological catalyst of free radical reactions and the Fenton reaction, iron has also been implicated in all diseases associated with free radical pathology and tissue damage. Furthermore, the recent discovery of ferroptosis, which is a cell death program based on free radical generation by iron and cell membrane lipid oxidation, sparked thousands of investigations and the association of iron with cardiac, kidney, liver, and many other diseases, including cancer and infections. The toxicity implications of iron in a labile, non-protein bound form and its complexes with dietary molecules such as vitamin C and drugs such as doxorubicin and other xenobiotic molecules in relation to carcinogenesis and other forms of toxicity are also discussed. In each case and form of iron toxicity, the mechanistic insights, diagnostic criteria, and molecular interactions are essential for the design of new and effective therapeutic interventions and of future targeted therapeutic strategies. In particular, this approach has been successful for the treatment of most iron loading conditions and especially for the transition of thalassemia from a fatal to a chronic disease due to new therapeutic protocols resulting in the complete elimination of iron overload and of iron toxicity.