Adriamycin-induced cardiomyopathy can serve as a model for diabetic cardiomyopathy – a hypothesis

Exploring the Pattern of Metabolic Alterations Causing Energy Imbalance via PPARα Dysregulation in Cardiac Muscle During Doxorubicin Treatment

Cardiotoxicity by anthracycline antineoplastic drug doxorubicin is one of the systemic toxicity of the cardiovascular system. The mechanism responsible for doxorubicin cardiotoxicity and lipid metabolism remains elusive. The current study tested the hypotheses that the role of peroxisome proliferator-activated receptor α (PPARα) in the progress of doxorubicin-induced cardiomyopathy and its mechanism behind lipid metabolism. In the present study, male rats were subjected to intraperitoneal injection (5-week period) of doxorubicin with different dosages such as low dosage (1.5 mg/kg body weight) and high dosage (15 mg/kg body weight) to induce doxorubicin cardiomyopathy. Myocardial PPARα was impaired in both low dosage and high dosage of doxorubicin-treated rats in a dose-dependent manner. The attenuated level of PPARα impairs the expression of the genes involved in mitochondrial transporter, fatty acid transportation, lipolysis, lipid metabolism, and fatty acid oxidation. Moreover, it disturbs the reverse triacylglycerol transporter apolipoprotein B-100 (APOB) in the myocardium. Doxorubicin elevates the circulatory lipid profile and glucose. Further aggravated lipid profile in circulation impedes the metabolism of lipid in cardiac tissue, which causes a lipotoxic condition in the heart and subsequently associated disease for the period of doxorubicin treatment. Elevated lipids in the circulation translocate into the heart dysregulates lipid metabolism in the heart, which causes augmented oxidative stress and necro-apoptosis and mediates lipotoxic conditions. This finding determines the mechanistic role of doxorubicin-disturbed lipid metabolism via PPARα, which leads to cardiac dysfunction.

Paeonol Reverses Adriamycin Induced Cardiac Pathological Remodeling through Notch1 Signaling Reactivation in H9c2 Cells and Adult Zebrafish Heart

Adriamycin is a commonly prescribed chemotherapeutic drug for a wide range of cancers. Adriamycin causes cardiotoxicity as an adverse effect that limits its clinical application in cancer treatment. Several mechanisms have been proposed to explain the toxicity it causes in heart cells. Disruption of inherent cardiac repair mechanism is the least understood mechanism of Adriamycin-induced cardiotoxicity. Adriamycin induces pathological remodeling in cardiac cells by promoting apoptosis, hypertrophy, and fibrosis. We found that Adriamycin inhibited Notch1 in a time- and dose-dependent manner in H9c2 cells. We used Paeonol, a Notch1 activator, and analyzed the markers of apoptosis, hypertrophy, and fibrosis in H9c2 cells in vitro and in adult zebrafish heart in vivo as model systems to study Adriamycin-induced cardiotoxicity. Paeonol activated Notch1 signaling and expression of its downstream target genes effectively in the Adriamycin-treated condition in vitro and in vivo. Also we detected that Notch activation using Paeonol protected the cells from apoptosis, collagen deposition, and hypertrophy response using functional assays. We conclude that Adriamycin induced cardiotoxicity by promoting the pathological cardiac remodeling through inhibition of Notch1 signaling and that the Notch1 reactivation by Paeonol protected the cells and reversed the cardiotoxicity.

Deciphering the molecular mechanism during doxorubicin-mediated oxidative stress, apoptosis through Nrf2 and PGC-1α in a rat testicular milieu

Doxorubicin is an extensively applied anti-cancerous drug since 1950's and its usage is constrained because of its accumulation in a non-cancerous organ. Many studies have proven that doxorubicin causes reproductive toxicity depends on its dosage, particularly due to increased oxidative stress and apoptosis. A number of the researches have been carried out concerning its prevention. But there is a need to recognize the mechanism at the back of its toxicity to get better and improved method of treatment. To clarify the feasible mechanism of doxorubicin-mediated reproductive toxicity in rats, we have administrated doxorubicin at distinct dosages inclusive of low dosage (male rats that are at 230-250 g acquired cumulatively 1.5 mg/kg; ip; once per week for five weeks) and high dosage (male rats which are at 230-250 grams obtained cumulatively 15 mg/kg; ip; once every week for five weeks). Doxorubicin decreases antioxidant level such as GSH, Cu/Zn SOD, Mn SOD both in serum and testes. Increased oxidative stress is considered via elevated MDA level both in serum and testes. The level of ROS is measured via the DCFDA method in testes. Apoptosis become found through DNA fragmentation assay and quantification of Caspase 3, Caspase 9, Bcl2 and Cytochrome C. Doxorubicin mediated oxidative stress and apoptosis in testicular milieu is through deregulation of Nrf2, PGC-1α, AHR, ARNT, PXR, SUMO-1, UCP2, UCP3, ANX A5, Caspase 3, Caspase 9, Bcl2, Cytochrome C, GR, and GPX. In end, doxorubicin-mediated oxidative stress and apoptosis is through diverse transcriptional factors and genes with respect to decreased antioxidant level, augmented ROS level and Annexin A5 in the testicular milieu.

Elevated lipolysis in adipose tissue by doxorubicin via PPARα activation associated with hepatic steatosis and insulin resistance

Adipose dysfunction is tightly associated with hepatic insulin resistance and steatosis condition. Doxorubicin would disturb the lipid metabolism both in adipose and liver. Here we projected that doxorubicin would impede lipogenesis and elevated lipolysis in adipose tissue would elevate the circulatory lipid profile and leads to insulin resistance. Further exacerbated lipid profile in circulation would impair the lipid metabolism in hepatic tissue which leads to fatty liver condition and consequently related disease during doxorubicin treatment. Doxorubicin impairs the lipogenesis through PPARγ and augments lipolysis and fatty acid oxidation through ATGL and PPARα in adipose tissue. Increased fatty acid level by adipose tissue in circulation would translocate into the liver and dysregulates AHR, PXR, PPARγ, ATGL and Apo B,which further develop insulin resistance and hepatic steatosis condition. The findings add to the mechanistic role of association between adipose tissue dysfunction and hepatic dysfunction.