Hemodynamic effects of HPMA copolymer based doxorubicin conjugate: A randomized controlled and comparative spectral study in conscious rats

Carnosic acid mitigates doxorubicin-induced cardiac toxicity: Evidence from animal and cell model investigations

Objectives

Utilization of doxorubicin (DOX) as a chemotherapy medication is limited due to its cardiotoxic effects. Carnosic acid exerts antioxidant, anti-inflammatory, besides cytoprotective effects. The objective of this study was to investigate the ability of carnosic acid to protect rat hearts and the MCF7 cell line against cardiotoxicity induced by DOX.

Materials and Methods

The study involved the classification of male Wistar rats into seven groups: 1) Control 2) DOX (2 mg/kg, every 48h, IP, 12d), 3-5) Carnosic acid (10, 20, 40 mg/kg/day, IP, 16d)+ DOX, 6) Vitamin E (200 mg/kg, every 48h, IP, 16d)+ DOX 7) Carnosic acid (40 mg/kg/day, IP, 16d). Finally, cardiac histopathological alterations, ECG factors, carotid blood pressure, left ventricular function, heart-to-body weight ratio, oxidative (MDA, GSH), inflammatory (IL-1β, TNF-α), plus apoptosis (caspase 3, 8, 9, Bcl-2, Bax) markers were evaluated. DOX toxicity and carnosic acid ameliorative effect were evaluated on MCF7 cells using the MTT assay.

Results

DOX augmented the QRS duration, QA, RRI, STI, and heart-to-body weight ratio, and reduced HR, LVDP, Min dP/dt, Max dP/dt, blood pressure, boosted MDA, TNF-α, IL1-β, caspase 3,8,9, Bax/Bcl-2 ratio, decreased GSH content, caused fibrosis, necrosis, and cytoplasmic vacuolization in cardiac tissue but carnosic acid administration reduced the toxic effects of DOX. The cytotoxic effects of DOX were not affected by carnosic acid at concentrations of 5 and 10 μM.

Conclusion

Carnosic acid as an anti-inflammatory and antioxidant substance is effective in reducing DOX-induced damage by enhancing antioxidant defense and modifying inflammatory signal pathway activity and can be used as an adjunct in treating DOX cardiotoxicity.

Thiosemicarbazones Can Act Synergistically with Anthracyclines to Downregulate CHEK1 Expression and Induce DNA Damage in Cell Lines Derived from Pediatric Solid Tumors

Anticancer therapy by anthracyclines often leads to the development of multidrug resistance (MDR), with subsequent treatment failure. Thiosemicarbazones have been previously suggested as suitable anthracycline partners due to their ability to overcome drug resistance through dual Pgp-dependent cytotoxicity-inducing effects. Here, we focused on combining anthracyclines (doxorubicin, daunorubicin, and mitoxantrone) and two thiosemicarbazones (DpC and Dp44mT) for treating cell types derived from the most frequent pediatric solid tumors. Our results showed synergistic effects for all combinations of treatments in all tested cell types. Nevertheless, further experiments revealed that this synergism was independent of Pgp expression but rather resulted from impaired DNA repair control leading to cell death via mitotic catastrophe. The downregulation of checkpoint kinase 1 (CHEK1) expression by thiosemicarbazones and the ability of both types of agents to induce double-strand breaks in DNA may explain the Pgp-independent synergism between anthracyclines and thiosemicarbazones. Moreover, the concomitant application of these agents was found to be the most efficient approach, achieving the strongest synergistic effect with lower concentrations of these drugs. Overall, our study identified a new mechanism that offers an avenue for combining thiosemicarbazones with anthracyclines to treat tumors regardless the Pgp status.

Protective Effect of Rifampicin Loaded by HPMA-PLA Nanopolymer on Macrophages Infected with Mycobacterium Tuberculosis

Purpose

This research was designed to investigate the protective effect of rifampicin (RIF) loaded by N-(2-hydroxypropyl) methylacrylamide- (HPMA-) polylactic acid (PLA) nanopolymer on macrophages infected with Mycobacterium tuberculosis (MTB).

Methods

We first induced H37Rv to infect macrophages to build a cell model. Then, the HPMA-PLA nanopolymer loaded with RIF was prepared to treat MTB-infected macrophages. The macrophage activity was tested by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the nitric oxide (NO) in cells was measured through Griess reagent, and the bacterial activity of MTB was observed via the colony-forming unit (CFU) assay. The inflammation-related factors in cells were detected via the enzyme-linked immunosorbent assay (ELISA), the apoptosis of macrophages was examined via flow cytometry, and the expression of apoptosis-related proteins was determined by western blot (WB).

Results

HPMA-PLA had no obvious toxicity to macrophages. The expression of NO and inflammatory factors in macrophages infected with MTB increased significantly, but the apoptosis rate was not significantly different from that of uninfected cells. However, after treatment with HPMA-PLA-RIF or free RIF, the inflammatory reaction of infected cells was inhibited, the expression of NO was decreased, the apoptosis rate was increased, and the bacterial activity in cells was decreased, with statistically significant differences; moreover, HPMA-PLA-RIF was more effective than free RIF.

Conclusions

HPMA-PLA-RIF has a high protective effect on macrophages infected with MTB, with high safety. Its protective mechanism is at least partly through inhibiting the production of NO and inflammatory response, which can inhibit bacterial activity and induce cell apoptosis.

Novel self-assembled nanogels of PEG-grafted poly HPMA with bis(α-cyclodextrin) containing disulfide linkage: synthesis, bio-disintegration, and in vivo biocompatibility

Synthesis of self-assembled nanogels of PEG-grafted poly HPMA with bis(α-cyclodextrin) containing disulfide linkage.

Paroxetine mitigates cardiac remodelling by doxorubicin and increases survival

Doxorubicin (DOX) is an effective anticancer drug. However, its use is hampered by the development of very mortal cardiomyopathy. Here, we investigate whether the co-administration of the antidepressant paroxetine (P), known to exert beneficial cardiovascular effects, would provide effective cardioprotection. Experiments were performed in male Wistar rats randomly assigned to control group (0.5 mL/kg 0.9% NaCl, i.v., n = 7), DOX group (DOX 5 mg /kg i.v., n = 23) and DOX+P group (DOX 5 mg/kg, i.v. plus P 10 mg/kg p.o. daily, beginning five days before DOX administration and during the follow-up period, n = 11). Rats' body weight and echocardiography parameters were monitored before and after drug/vehicle administration. Cardiac histology was performed post-mortem, as well as beta1-adrenergic receptor (β₁-AR), beta2-adrenergic receptor (β₂-AR), G protein-coupled receptor kinases type 2 (GRK2), type 3 (GRK3), beta-arrestin 1, and beta-arrestin 2 gene expression using RT-qPCR. DOX-treated rats exhibited bad general condition, adynamia, loss of body weight, and low survival. Echocardiography revealed two phenotypes: cardiomyopathy with left ventricular (LV) hypertrophy (DOX-HCM) and cardiomyopathy with LV dilation (DOX-DCM). In DOX-HCM rats only, there was an increased GRK2 and GRK3 gene expression and synthesis. DOX+P co-treated rats exhibited good general condition, normal spontaneous behaviour, gained weight over time, had increased survival, and preserved LV morphology and contractility. In these rats, gene expression and synthesis of GRK2 and GRK3 were decreased, while β₁-AR and β₂-AR were increased. Present results show for the first time that P effectively reduces DOX-induced cardiotoxicity and enhances survival.

In Vivo and In Vitro Protective Effects of Rosmarinic Acid against Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is an anticancer medicine that may trigger cardiomyopathy. Rosmarinic acid (RA) has shown antioxidant, anti-inflammatory, and anticancer effects. This investigation assessed the cardioprotective effect of RA on DOX-induced-toxicity in both in vivo and in vitro experiments. Male rats were randomized on 7 groups: (1) control, (2) DOX (2 mg/kg, per 48 h, 12d, i.p), (3) RA (40 mg/kg, 12d, i.p.), (4-6) RA (10, 20, 40 mg/kg, 16d, i.p.)+ DOX, (7) Vitamin E (200 mg/kg, per 48 h, 16d, i.p.) + DOX and then indices of cardiac function were estimated. Also, DOX and rosmarinic acid effects were examined on MCF7 cells (breast cancer cells line) to clarify that both cardiotoxicity and anticancer effects were analyzed. DOX increased heart to body weight ratio, RRI, QA, STI, QRS duration and voltage, attenuated HR, blood pressure, Max dP/dt, Min dP/dt, LVDP, enhanced MDA, declined GSH amount, and caused fibrosis and necrosis in cardiac tissue. Administration of RA ameliorated the toxic effects of DOX. In vitro studies showed that RA did not affect the cytotoxic effect of DOX. RA as an antioxidant, anti-inflammatory, and cardioprotective compound could be a promising compound to help minimize DOX-induced cardiotoxicity.

Strategies for the design of nanoparticles: starting with long-circulating nanoparticles, from lab to clinic

Short half-life is one of the main causes of drug attrition in clinical development, which also leads to the failure of many leading compounds and hits to become drug candidates. Nowadays, nanomaterials have been applied to drug development to address this problem. In fact, the clinical application of nanoparticles (NPs) is severely limited due to their rapid elimination by the reticuloendothelial system (RES) in vivo. In this paper, we aim to summarize representative strategies on prolonging the circulation time for bridging the gap between excellent pharmaceutics and proper half-life and encourage clinical translation.

Phenomapping for classification of doxorubicin-induced cardiomyopathy in rats

Cardiomyopathy resistant to treatment is the most serious adverse effect of doxorubicin (dox). The mechanisms of dox-induced cardiomyopathy (DCM) have been extensively studied in dilated forms of DCM. However, efficient treatment did not emerge. The aim of the present work was to revisit the experimental model of DCM in rats, to define phenotype/s and associate them to the changes in cardiac transcriptome. Male Wistar rats equipped with radiotelemetry device, were randomized in DOX group (5 mg/0,5 mL/kg, IV dox; n = 18) and CONT group (0,5 mL/kg IV saline; n = 6). Echocardiography, autonomic spectral markers and baroreceptor reflex evaluation was performed prior to, and after treatment. Blood samples were collected at the end of experimentation. Cardiac, renal and hepatic tissues were analysed post-mortem by histology. Changes in expression of key cardiac genes affected by dox were assessed by RT-qPCR. Phenotypes were identified by clustering non-redundant features using four different algorithms averaged by evidence accumulation cluster technique. The results emphasize the existence of two major phenotypes of DCM with comparably high mortality rates: phenotype 1 characterized by, left ventricular (LV) dilatation, thinning of LV posterior wall, reduced LV ejection fraction (LVEF) and fractional shortening (LVFS), decreased HR variability (HRV), decreased baroreceptor effectiveness index (BEI) and increased NT-proBNP; and phenotype 2 with LV hypertrophy - increased LV mass, preserved LVEF, LVFS, no changes in HRV and BEI and moderate NT-proBNP increase. Both phenotypes exhibited a genetic shift to a new-born program.

Polymeric micelles in cancer therapy: State of the art

In recent years, polymeric micelles have been extensively utilized in pre-clinical studies for delivering poorly soluble chemotherapeutic agents in cancer. Polymeric micelles are formed via self-assembly of amphiphilic polymers in facile manners. The wide availability of hydrophobic and, to some extent, hydrophilic polymeric blocks allow researchers to explore various polymeric combinations for optimum loading, stability, systemic circulation, and delivery to the target cancer tissues. Moreover, polymeric micelles could easily be tailor-made by increasing and decreasing the number of monomers in each polymeric chain. Some of the widely accepted hydrophobic polymers are poly(lactide) (PLA), poly(caprolactone) (PCL), poly(lactide-co-glycolide) (PLGA), polyesters, poly(amino acids), lipids. The hydrophilic polymers used to wrap the hydrophobic core are poly(ethylene glycol), poly(oxazolines), chitosan, dextran, and hyaluronic acids. Drugs could be conjugated to polymers at the distal ends to prepare pharmacologically active polymeric systems that impart enhanced solubility and stability of the conjugates and provide an opportunity for combination drug delivery. Their nano-size enables them to accumulate to the tumor microenvironment via the Enhanced Permeability and Retention (EPR) effect. Moreover, the stimuli-sensitive breakdown provides the micelles an effective means to deliver the therapeutic cargo effectively. The tumor micro-environmental stimuli are pH, hypoxia, and upregulated enzymes. Externally applied stimuli to destroy micellar disassembly to release the payload include light, ultrasound, and temperature. This article delineates the current trend in developing polymeric micelles combining various block polymeric scaffolds. The development of stimuli-sensitive micelles to achieve enhanced therapeutic activity are also discussed.

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.

Metabolic and non-metabolic pathways that control cancer resistance to anthracyclines

Anthracyclines Doxorubicin, Epirubicin, Daunorubicin and Idarubicin are used to treat a variety of tumor types in the clinics, either alone or, most often, in combination therapies. While their cardiotoxicity is well known, the emergence of chemoresistance is also a major issue accounting for treatment discontinuation. Resistance to anthracyclines is associated to the acquisition of multidrug resistance conferred by overexpression of permeability glycoprotein-1 or other efflux pumps, by altered DNA repair, changes in topoisomerase II activity, cancer stemness and metabolic adaptations. This review further details the metabolic aspects of resistance to anthracyclines, emphasizing the contributions of glycolysis, the pentose phosphate pathway and nucleotide biosynthesis, glutathione, lipid metabolism and autophagy to the chemoresistant phenotype.

Cardiovascular variability and β-ARs gene expression at two stages of doxorubicin - Induced cardiomyopathy

Using comprehensive analysis of heart rate (HRV) and blood pressure (BPV) short-term variability we estimated the time course of changes of autonomic nervous system remodeling in two stages of doxorubicin-induced cardiomyopathy (DCM). We also investigated the level of gene expression of cardiac β-1 (β-1AR) and β-2 (β-2AR) adrenoceptors. Experiments were performed in adult male Wistar rats equipped with indwelling catheters for BP recording and blood withdrawal. A 15 mg/kg total cumulative dose of doxorubicin was injected i.p. to rats to induce DCM or saline for control (n=18). Rats were assessed for general toxicity, cardiovascular hemodynamic and echocardiography before treatment (n=6), 35 days (DOX35; n=6) and 70 days (DOX70; n=6) post-treatment. HRV was evaluated by spectral analysis, Poincaré plots, sample and approximate entropy. Expression of β-1AR and β-2AR mRNA was evaluated by RT-qPCR. Doxorubicin-treated rats exhibited poor general condition and lower survival than saline-treated rats. In DOX35 rats, there were no echocardiography signs of decompensation, no increase in serum cardiac troponins, but there was an increase of HRV and decrease of HR complexity. In these rats typical microscopic signs of cardiotoxicity were seen along with over-expression of β-1AR mRNA. 70 days post-treatment echocardiography revealed signs of decompensation and serum cardiac troponin T was increased. At this stage BPV decreased. In conclusion, HRV increase matches transient over-expression of cardiac β-1AR mRNA in compensate stage of DCM while decompensate stage of DCM is characterized by a decrease of BPV and no changes in β-1AR and β-2AR gene expression.

Sudden death: Neurogenic causes, prediction and prevention

Sudden death is a major health problem all over the world. The most common causes of sudden death are cardiac but there are also other causes such as neurological conditions (stroke, epileptic attacks and brain trauma), drugs, catecholamine toxicity, etc. A common feature of all these diverse pathologies underlying sudden death is the imbalance of the autonomic nervous system control of the cardiovascular system. This paper reviews different pathologies underlying sudden death with emphasis on the autonomic nervous system contribution, possibilities of early diagnosis and prognosis of sudden death using various clinical markers including autonomic markers (heart rate variability and baroreflex sensitivity), present possibilities of management and promising prevention by electrical neuromodulation.

The Light at the End of the Tunnel-Second Generation HPMA Conjugates for Cancer Treatment

It is almost four decades since N-(2-hydroxypropyl)methacrylamide (HPMA) - based copolymers arose as drug carriers. Although fundamentals have been established and significant advantages have been proved, the commercialization of this platform technology was hampered due to modest outcome of clinical trial initiated with PK1, the symbol of first generation polymer-drug conjugates. In this review, we illustrate the exciting progress and approaches offered by more effective 2^nd generation HPMA-based polymer-drug conjugates in cancer treatment. For example, a new synthetic strategy endorses inert HPMA polymer with biodegradability, which permitted to prepare high molecular weight HPMA-drug conjugates with simple linear architecture while maintaining good biocompatibility. As expected, extended long-circulating pharmacokinetics and enhanced antitumor activities were achieved in several preclinical investigations. In addition, greater inhibition of tumor growth in combination regimes exhibits the remarkable capability and flexibility of HPMA-based macromolecular therapeutics. The review also discusses the main challenges and strategies for further translation development of 2^nd generation HPMA-based polymer-drug conjugates.