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10 záznamů v Medvik Filtry

Článek

Early and delayed cardioprotective intervention with dexrazoxane each show different potential for prevention of chronic anthracycline cardiotoxicity in rabbits

Toxicology. 2013 ; 311 (3) : 191-204.

ISSN 1879-3185
Medvik
Zdroj

Despite incomplete understanding to its mechanism of action, dexrazoxane (DEX) is still the only clearly effective cardioprotectant against chronic anthracycline (ANT) cardiotoxicity. However, its clinical use is currently restricted to patients exceeding significant ANT cumulative dose (300mg/m(2)), although each ANT cycle may induce certain potentially irreversible myocardial damage. Therefore, the aim of this study was to compare early and delayed DEX intervention against chronic ANT cardiotoxicity and study the molecular events involved. The cardiotoxicity was induced in rabbits with daunorubicin (DAU; 3mg/kg/week for 10 weeks); DEX (60mg/kg) was administered either before the 1st or 7th DAU dose (i.e. after ≈300mg/m(2) cumulative dose). While both DEX administration schedules prevented DAU-induced premature deaths and severe congestive heart failure, only the early intervention completely prevented the left ventricular dysfunction, myocardial morphological changes and mitochondrial damage. Further molecular analyses did not support the assumption that DEX cardioprotection is based and directly proportional to protection from DAU-induced oxidative damage and/or deletions in mtDNA. Nevertheless, DAU induced significant up-regulation of heme oxygenase 1 pathway while heme synthesis was inversely regulated and both changes were schedule-of-administration preventable by DEX. Early and delayed DEX interventions also differed in ability to prevent DAU-induced down-regulation of expression of mitochondrial proteins encoded by both nuclear and mitochondrial genome. Hence, the present functional, morphological as well as the molecular data highlights the enormous cardioprotective effects of DEX and provides novel insights into the molecular events involved. Furthermore, the data suggests that currently recommended delayed intervention may not be able to take advantage of the full cardioprotective potential of the drug.

MeSH
citrátsynthasa metabolismus MeSH
daunomycin toxicita MeSH
faktor 2 související s NF-E2 metabolismus MeSH
funkce levé komory srdeční účinky léků MeSH
kardiotonika aplikace a dávkování MeSH
králíci MeSH
nemoci srdce chemicky indukované metabolismus patologie prevence a kontrola MeSH
oxidační stres MeSH
protinádorová antibiotika toxicita MeSH
razoxan aplikace a dávkování MeSH
troponin T krev MeSH
zvířata MeSH
Check Tag
králíci MeSH
mužské pohlaví MeSH
zvířata MeSH
Publikační typ
časopisecké články MeSH
práce podpořená grantem MeSH

Článek

Protective effects of dexrazoxane against acute ischaemia/reperfusion injury of rat hearts

Canadian journal of physiology and pharmacology. 2012 ; 90 (9) : 1303-10.

Can J Physiol Pharmacol
ISSN 1205-7541
Medvik
Zdroj

Dexrazoxane (DEX), an inhibitor of topoisomerase II and intracellular iron chelator, is believed to reduce the formation of reactive oxygen species (ROS) and protects the heart from the toxicity of anthracycline antineoplastics. As ROS also play a role in the pathogenesis of cardiac ischaemia/reperfusion (I/R) injury, the aim was to find out whether DEX can improve cardiac ischaemic tolerance. DEX in a dose of 50, 150, or 450 mg·(kg body mass)(-1) was administered intravenously to rats 60 min before ischaemia. Myocardial infarct size and ventricular arrhythmias were assessed in anaesthetized open-chest animals subjected to 20 min coronary artery occlusion and 3 h reperfusion. Arrhythmias induced by I/R were also assessed in isolated perfused hearts. Only the highest dose of DEX significantly reduced infarct size from 53.9% ± 4.7% of the area at risk in controls to 37.5% ± 4.3% without affecting the myocardial markers of oxidative stress. On the other hand, the significant protective effect against reperfusion arrhythmias occurred only in perfused hearts with the dose of DEX of 150 mg·kg(-1), which also tended to limit the incidence of ischaemic arrhythmias. It is concluded that DEX in a narrow dose range can suppress arrhythmias in isolated hearts subjected to I/R, while a higher dose is needed to limit myocardial infarct size in open-chest rats.

Článek

Long-term serial echocardiographic examination of late anthracycline cardiotoxicity and its prevention by dexrazoxane in paediatric patients

European journal of pediatrics. 2005 ; 164 (11) : 678-684.

Eur J Pediatr
ISSN 0340-6199
Medvik
Zdroj

The authors conducted an 8-year prospective non-randomised study to determine whether dexrazoxane (ICRF-187) would reduce late anthracycline-induced cardiotoxicity in patients treated in childhood for haematological malignancy. The authors examined prospectively 75 patients (40 male/35 female) aged 2-17 years (median 6.5 years) at the time of diagnosis. The cardioprotection was given to 53 patients (26 male/17 female) and the standard protocol was used in 22 patients (14 male/8 female). The prospective echocardiographic evaluation was done before and after the chemotherapy and every year during the follow-up period. Dynamic stress echocardiography (DSE) was assessed in the final year. The clinical cardiotoxicity was not diagnosed. Higher cumulative doses of anthracycline were given in the dexrazoxane group (234+/-58 mg/m(2), median 240 mg/m(2) versus 203+/-86 mg/m(2), median 210 mg/m(2), P <0.04) and a significantly higher percentage of patients received cumulative doses >240 mg/m(2) of anthracycline ( P <0.05). During the follow-up period, the fractional shortening (FS) declined in the no-dexrazoxane group only in the 8th year and was significantly lower compared to the dexrazoxane group ( P <0.05). The pathological decrease in FS was present in 24% of patients; 41% in the no-dexrazoxane and 17% in the dexrazoxane groups, respectively ( P <0.05). DSE demonstrated lower rest EF and cardiac index (CI) in the no-dexrazoxane group ( P <0.05); however, neither the response of EF and CI to the stress echocardiography nor the exercise tolerance significantly differed between sub-groups. A higher number of patients in the dexrazoxane group had very good exercise tolerance (ET) >3 Watts/kg ( P <0.05) and a lower number responded with a decreased ET <2 Watts/kg ( P <0.05) compared to the no-dexrazoxane group. CONCLUSION: Dexrazoxane seems to reduce the risk of late subclinical cardiotoxicity. Dexrazoxane-treated patients revealed better exercise tolerance; however the haemodynamic response to the stress was no different in both sub-groups.