Long-term cardiac effects of treatment for childhood leukemia

Omega 3 fatty acids can reduce early doxorubicin-induced cardiotoxicity in children with acute lymphoblastic leukemia

OBJECTIVES

Omega 3 polyunsaturated fatty acids are dietary factors with several beneficial cardiovascular effects. This study aimed to assess the possible protective effect of omega 3 fatty acids on early doxorubicin-induced cardiac toxicity in children with acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Sixty children of newly diagnosed ALL were randomized into two groups: group I (n = 30) who received omega 3 fatty acids 1000 mg/day for 6 months in addition to their usual protocol of chemotherapy including doxorubicin; and group II (n = 30) who received their usual doxorubicin protocol during the period from February 2020 till August 2021. Echocardiographic examinations were performed before and after the treatment. Glutathione, malondialdehyde (MDA), superoxide dismutase (SOD), troponin I, creatine kinase MB (CK-MB), and N-terminal pro-brain natriuretic peptide (NT-proBNP) were measured also before and after omega 3 treatment.

RESULTS

After 6 months of omega 3 administration, group I had a significantly lower MDA level and a significantly higher glutathione and SOD levels than group II. Similarly, the levels of troponin I, CK-MB, and NT-proBNP were significantly high in group II, whereas they were unchanged in group I after treatment. Similarly, systolic function (presented with peak mitral annular systolic velocity and two-dimensional global longitudinal strain) of the heart was preserved in omega 3-treated patients, unlike the control group that showed significant impairment of left ventricular function after 6 months.

CONCLUSION

Omega 3 fatty acids may decrease early cardiac injury and doxorubicin-induced cardiotoxicity in children with ALL.

Sex-related differential susceptibility to doxorubicin-induced cardiotoxicity in B6C3F1 mice

Sex is a risk factor for development of cardiotoxicity, induced by the anti-cancer drug, doxorubicin (DOX), in humans. To explore potential mechanisms underlying differential susceptibility to DOX between sexes, 8-week old male and female B6C3F₁ mice were dosed with 3mg/kg body weight DOX or an equivalent volume of saline via tail vein once a week for 6, 7, 8, and 9 consecutive weeks, resulting in 18, 21, 24, and 27mg/kg cumulative DOX doses, respectively. At necropsy, one week after each consecutive final dose, the extent of myocardial injury was greater in male mice compared to females as indicated by higher plasma concentrations of cardiac troponin T at all cumulative DOX doses with statistically significant differences between sexes at the 21 and 24mg/kg cumulative doses. A greater susceptibility to DOX in male mice was further confirmed by the presence of cytoplasmic vacuolization in cardiomyocytes, with left atrium being more vulnerable to DOX cardiotoxicity. The number of TUNEL-positive cardiomyocytes was mostly higher in DOX-treated male mice compared to female counterparts, showing a statistically significant sex-related difference only in left atrium at 21mg/kg cumulative dose. DOX-treated male mice also had an increased number of γ-H2A.X-positive (measure of DNA double-strand breaks) cardiomyocytes compared to female counterparts with a significant sex effect in the ventricle at 27mg/kg cumulative dose and right atrium at 21 and 27mg/kg cumulative doses. This newly established mouse model provides a means to identify biomarkers and access potential mechanisms underlying sex-related differences in DOX-induced cardiotoxicity.

The minipig as a new model for the evaluation of doxorubicin-induced chronic toxicity

Doxorubicin can cause life-threatening toxic effects in several organs, with cardiotoxicity being the major concern. Although a large number of animal models have been utilized to study doxorubicin toxicity, several restrictions limit their use. Since the Göttingen minipig is an accepted species for non-clinical safety assessment and translation to man, we aimed at exploring its use as a non-rodent animal model for safety assessment and regulatory toxicity studies using doxorubicin. Three groups of three males and three females adult Göttingen minipigs received 1.5 mg kg(-1) , 3/2.3 mg kg(-1) or vehicle at intervals of 3 weeks for 7 cycles. Doxorubicin treatment resulted in a dose-related decrease in the erythrocytes, hemoglobin and hematocrit count, accompanied by leukopenia and thrombocytopenia. Bone marrow smears revealed dose-related hypocellularity. Urea and creatinine levels were elevated in treated animals, associated with proteinuria and hematuria. Histopathological evaluation detected nephropathy and atrophy of hematopoietic tissues/organs, mucosa of the intestinal tract and male genital tract. Cardiac lesions including chronic inflammation, endocardial hyperplasia, hemorrhage and myxomatous changes were evident in hematoxylin and eosin stains, and evaluation of semi-thin sections showed the presence of dose-related vacuolation in the atrial and ventricular cardiomyocytes. Cardiac troponin levels were increased in the high-dose group, but there was no direct correlation to the severity of the histopathological lesions. This study confirms that the Göttingen minipig has a comparable toxicity profile to humans and considering its anatomical, physiological, genetic and biochemical resemblance to humans, it should be considered as the non-rodent species of choice for studies on doxorubicin toxicity. Copyright © 2015 John Wiley & Sons, Ltd.

NT-proBNP as early marker of subclinical late cardiotoxicity after doxorubicin therapy and mediastinal irradiation in childhood cancer survivors

Background. Childhood cancer survivors treated with anthracyclines and mediastinal irradiation are at risk for late onset cardiotoxicity. Aims of the Study. To assess the role of N-terminal pro-brain natriuretic peptide (NT-proBNP) and tissue Doppler imaging (TDI) as early predictors of late onset cardiotoxicity in asymptomatic survivors of childhood cancer treated with doxorubicin with or without mediastinal irradiation. Methods. A cross-sectional study on 58 asymptomatic survivors of childhood cancer who received doxorubicin in their treatment protocols and 32 asymptomatic Hodgkin's lymphoma survivors who received anthracycline and mediastinal irradiation. Levels of NT-proBNP, TDI, and conventional echocardiography were determined. Results. Thirty percent of survivors had abnormal NT-proBNP levels. It was significantly related to age at diagnosis, duration of follow-up, and cumulative dose of doxorubicin. TDI detected myocardial affection in 20% more than conventional echocardiography. Furthermore, abnormalities in TDI and NT-pro-BNP levels were more common in Hodgkin lymphoma survivors receiving both chemotherapy and radiotherapy. Conclusions. TDI could detect early cardiac dysfunction even in those with normal conventional echocardiography. Measurement of NT-proBNP represents an interesting strategy for detecting subclinical cardiotoxicity. We recommend prospective and multicenter studies to validate the role of NT-proBNP as an early marker for late onset doxorubicin-induced cardiotoxicity.

Development of doxorubicin-induced chronic cardiotoxicity in the B6C3F1 mouse model

Serum levels of cardiac troponins serve as biomarkers of myocardial injury. However, troponins are released into the serum only after damage to cardiac tissue has occurred. Here, we report development of a mouse model of doxorubicin (DOX)-induced chronic cardiotoxicity to aid in the identification of predictive biomarkers of early events of cardiac tissue injury. Male B6C3F(1) mice were administered intravenous DOX at 3mg/kg body weight, or an equivalent volume of saline, once a week for 4, 6, 8, 10, 12, and 14weeks, resulting in cumulative DOX doses of 12, 18, 24, 30, 36, and 42mg/kg, respectively. Mice were sacrificed a week following the last dose. A significant reduction in body weight gain was observed in mice following exposure to a weekly DOX dose for 1week and longer compared to saline-treated controls. DOX treatment also resulted in declines in red blood cell count, hemoglobin level, and hematocrit compared to saline-treated controls after the 2nd weekly dose until the 8th and 9th doses, followed by a modest recovery. All DOX-treated mice had significant elevations in cardiac troponin T concentrations in plasma compared to saline-treated controls, indicating cardiac tissue injury. Also, a dose-related increase in the severity of cardiac lesions was seen in mice exposed to 24mg/kg DOX and higher cumulative doses. Mice treated with cumulative DOX doses of 30mg/kg and higher showed a significant decline in heart rate, suggesting drug-induced cardiac dysfunction. Altogether, these findings demonstrate the development of DOX-induced chronic cardiotoxicity in B6C3F(1) mice.

Role of NT-proBNP in detection of myocardial damage in childhood leukemia survivors treated with and without anthracyclines

Background

Exposure to anthracyclines (ANT) during childhood represents a high risk for development of late cardiotoxicity. Cardiotoxicity is usually detected only when clinical symptoms or progressive cardiac dysfunction have already occurred. Early detection of cardiotoxicity may lead to better therapeutic outcome. N-terminal pro-brain natriuretic peptide (NTproBNP) has been hypothesized to reflect increased left ventricular wall stress before development of echocardiographic abnormalities. The aim of this study was to detect cardiac abnormalities using plasma NTproBNP and echocardiography in asymptomatic childhood leukemia survivors treated with or without cardiotoxic anthracycline therapy.

Methods

Serum levels of NTproBNP were determined in 69 asymptomatic survivors of childhood leukemia treated with or without anthracyclines and in 44 apparently healthy controls. The survivors were divided into two treatment groups: 36 patients after chemotherapy containing anthracyclines (ANT) and 33 patients after chemotherapy without anthracyclines (nonANT). Levels of NTproBNP were measured by using the Elecsys 2010 immunoassay analyzer (Roche Diagnostics). Echocardiography using M-mode, two-dimensional and Doppler measurements were performed on the same day as blood samples were obtained for NTproBNP analysis in survivors.

Results

Serum levels of NTproBNP were significantly higher in the ANT group than in controls (median 51.52 vs 17.37 pg/ml; p=0.0026). Survivors exposed to ANT had significantly increased levels of NTproBNP compared with patients treated without ANT (median 51.52 vs 12.24 pg/ml; p=0.0002). Female exposed and unexposed survivors had significantly higher NTproBNP levels than males. Four of the 36 survivors (11%) treated with ANT and two of the 33 patients (6%) not exposed to ANT had abnormal NTproBNP levels. Although no patient had echocardiographic abnormalities, significant differences were found in values of left ventricular ejection fraction (LVEF) and deceleration time (DT) between survivors treated with or without anthracyclines.

Conclusions

Higher levels of NTproBNP detected in childhood leukemia survivors after low anthracycline cumulative doses might reflect an initial stage of ANT cardiotoxicity before the development of echocardiographic abnormalities. Although the current studies support NTproBNP as one of the best available biochemical markers of late anthracycline cardiotoxicity, a possible strategy toward further improvement and combination with other cardiac biomarkers and novel echocardiographic methods should be explored in additional studies.

Role of biomarkers in cardioncology

Cardiotoxicity is a serious adverse effect of anticancer drugs, impacting on quality of life and overall survival of cancer patients. According to the current standard for monitoring cardiac function, cardiotoxicity is usually detected only when a functional impairment has already occurred, precluding any chance of preventing its development. Over the last decade, however, a new approach, based on the use of cardiac biomarkers, has emerged, and has proven to be an effective alternative strategy for early detection of subclinical cardiac injury. In particular, the role of troponin I in identifying patients at risk of cardiotoxicity and of angiotensin-converting enzyme inhibitors in preventing left ventricular ejection fraction reduction and late cardiac events represent an effective tool for the prevention of this complication.

Cardiac function in survivors of acute lymphoblastic leukaemia and Hodgkin's lymphoma

AIM

The study objective was to assess plasma N-terminal-pro-brain natriuretic peptide (BNP) levels and to evaluate left ventricular mass as well as left ventricular systolic and diastolic functions in 44 children who had undergone treatment for acute lymphoblastic leukaemia and Hodgkin's lymphoma, with regard to gender, age at disease onset, time that had passed since therapy completion, cumulative dose of antracyclines and mediastinal radiotherapy applied.

METHODS

The median levels of pro-BNP were found to be higher in the whole study group as compared with the control (55.9 ± 53.1 ng/mL vs. 38.5 ± 47.7 ng/mL, P= 0.059). The pro-BNP values >80.0 ng/mL (standard deviation score (SDS)) were noted in 11/44 patients, including those exceeding 115.0 ng/mL (2 SDS) - in 6/44 patients.

RESULTS

No correlation was observed of pro-BNP levels with the accumulated dose of antracyclines (r=-0.42, P= 0.79) or mediastinal radiotherapy (r= 0.197, P= 0.2). However, negative correlation was found between pro-BNP and the time that had passed since therapy completion (r=-0.378, P= 0.009). In echocardiography, shortening and ejection fractions remained normal, whereas the indexed stroke volume was below 40 mL/m(2) in 16/44 patients. The E/A index below 1.5 was found in 6/44 cases. The left ventricular systolic mass remained within the normal range. Negative correlation was noted between isovolumetric diastolic time and pro-BNP level.

CONCLUSIONS

Increased levels of pro-BNP after anti-cancer treatment with the involvement of cardiotoxic substances may indicate the first symptoms of myocardial dysfunction, despite the lack of major echocardiographic disorders.