Ferric Carboxymaltose-Mediated Attenuation of Doxorubicin-Induced Cardiotoxicity in an Iron Deficiency Rat Model

Since anthracycline-induced cardiotoxicity (AIC), a complication of anthracycline-based chemotherapies, is thought to involve iron, concerns exist about using iron for anaemia treatment in anthracycline-receiving cancer patients. This study evaluated how intravenous ferric carboxymaltose (FCM) modulates the influence of iron deficiency anaemia (IDA) and doxorubicin (3–5 mg per kg body weight [BW]) on oxidative/nitrosative stress, inflammation, and cardiorenal function in spontaneously hypertensive stroke-prone (SHR-SP) rats. FCM was given as repeated small or single total dose (15 mg iron per kg BW), either concurrent with or three days after doxorubicin. IDA (after dietary iron restriction) induced cardiac and renal oxidative stress (markers included malondialdehyde, catalase, Cu,Zn-superoxide dismutase, and glutathione peroxidase), nitrosative stress (inducible nitric oxide synthase and nitrotyrosine), inflammation (tumour necrosis factor-alpha and interleukin-6), and functional/morphological abnormalities (left ventricle end-diastolic and end-systolic diameter, fractional shortening, density of cardiomyocytes and capillaries, caveolin-1 expression, creatinine clearance, and urine neutrophil gelatinase-associated lipocalin) that were aggravated by doxorubicin. Notably, iron treatment with FCM did not exacerbate but attenuated the cardiorenal effects of IDA and doxorubicin independent of the iron dosing regimen. The results of this model suggest that intravenous FCM can be used concomitantly with an anthracycline-based chemotherapy without increasing signs of AIC.

Iron can reduce doxorubicin-induced cardiotoxicity

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The supplemental file includes: Table S1. Renal function according to iron diet, DOX treatment and supplementation with FCM Table S2. Renal oxidative stress according to iron diet, DOX treatment and supplementation with FCM Table S3. Renal histological and immunohistochemical assessment according to iron diet, DOX treatment and supplementation with FCM Figure S1. Immunohistochemical evaluation of nitrosative stress in the kidney Figure S2. Immunohistochemical evaluation of inflammation in the kidney Iron can reduce doxorubicin-induced cardiotoxicity S3

Supplementary Methods
Modulation of DOX-induced kidney toxicity with FCM After 3 weeks acclimatisation, 6 week old male SHR-SP (n=64) were randomised into eight groups (Groups 1-8; n=8/group). Groups 1-6 were fed LID while Groups 7 and 8 were fed ND for 7 weeks. Then, Groups 1-5 and Group 8 received 6 weekly 0.5 mL i.p injections of DOX at 4 mg/kg BW. In addition, starting at the second weekly DOX injection, Groups 1 and 2 received 5 weekly 0.5 mL intravenous (i.v.) injections of ferric carboxymaltose (FCM) at 3 mg iron/kg BW in 0.5 ml concurrent with or 3 days after DOX treatment, respectively, while Groups 3 and 4 received a single 0.5 mL i.v. injection of FCM at 15 mg iron/kg BW concurrent with or 3 days after the second DOX injection, respectively. Group 8 (fed ND) received a single i.v. injection of FCM at 15 mg iron/kg BW concurrent with the second DOX injection. As a control for multiple FCM injections, Group 5 received 5 weekly i.v. injections of saline concurrent with DOX treatment. As controls for combined treatment with DOX and FCM, Group 6 (fed LID) and Group 7 (fed ND) received 6 weekly i.p. and 5 weekly i.v. saline injections, respectively. Two weeks after the last DOX injection, all rats were anaesthetised (sodium thiopental 40 mg/kg BW) and euthanised by subtotal exsanguination. Kidneys were perfused with saline and tissue samples taken from the blood-free organ for histological and immunohistochemical assessment.     counterstained with hematoxylin. The greatest level of nitrotyrosine immunostaining is seen in kidney sections from ND-fed rats treated with DOX and FCM (G8), followed by LID-fed rats treated with DOX (G5) and LID-fed rats treated with saline (G6). In LID-fed rats treated with DOX and FCM (G1-G4), staining was lower compared to G5, whereas only low levels of staining were seen in LID-fed rats treated with saline (G7). Similar Group trends were observed with iNOS immunostaining. Original magnification, x400.
Iron can reduce doxorubicin-induced cardiotoxicity S10 Figure S2. Immunohistochemical evaluation of inflammation in the kidney.
Representative light micrographs of kidney sections from Groups 1-8 (G1-G8) immunostained with antibodies against TNF-α (panel A) or IL-6 (panel B) and counterstained with hematoxylin. Significant proinflammatory cytokine immunostaining is seen in kidney sections from ND-fed rats treated with DOX and FCM (G8) and in LID-fed rats treated with DOX (G5). Lowest degree of staining is seen in ND-fed rats treated with saline (G7). In LIDfed rats treated with DOX and FCM (G1-G4), a moderate level of staining is observed similar to that seen in LID-fed rats treated with DOX only (G6). Original magnification, x400.