Non-protein bound iron release during chemotherapy in cancer patients.
Non-protein bound iron (NPBI) is able to catalyse oxidative reactions, causing damage to vital structures. Adverse effects induced by cisplatin seem, in part, to be mediated by free radicals. In the present study, we have measured plasma NPBI, various other iron parameters and antioxidants in 28 cancer patients undergoing cisplatin-based chemotherapy at various time points before and during chemotherapy. No NPBI was present prior to therapy, but within 1-4 days following the first administration of chemotherapy, mean NPBI rose significantly to 10.6+/-6.6 micromol/l (range, 0.6-21.3 micromol/l) in 18 (64.3%) of the 28 patients measured. The rise in NPBI was accompanied by a significant rise in total plasma iron and ferritin and a marked decrease in the latent iron-binding capacity. Concomitantly, plasma vitamins C and E decreased significantly, indicating consumption of antioxidants. Similar observations were also made during the fourth chemotherapy cycle. The increase in NPBI preceded and correlated significantly with chemotherapy toxicity, such as a decrease in leucocyte count and haemoglobin, with a transient rise in various liver enzymes and with known cisplatin-related toxicity, i.e. the loss of renal and hearing function. In conclusion, cisplatin chemotherapy induces oxidative damage which rapidly leads to release of iron from intracellular proteins and the appearance of NPBI. Bone marrow, red blood cells, liver and kidney seem to be a likely source of NPBI. The observed high levels of NPBI may be a major causative determinant in chemotherapy-induced toxicity.
Weijl
N I
NI
Department of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands.
Elsendoorn
T J
TJ
Moison
R M W
RM
Lentjes
E G W M
EG
Brand
R
R
Berger
H M
HM
Osanto
S
S
D000293:Adolescent; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D000975:Antioxidants / Q000378:metabolism; D001205:Ascorbic Acid / Q000097:blood / Q000627:therapeutic use; D002945:Cisplatin / Q000008:administration & dosage / Q000009:adverse effects; D005260:Female; D005293:Ferritins / Q000097:blood; D018237:Germinoma / Q000097:blood / Q000188:drug therapy*; D006309:Hearing / Q000187:drug effects; D006801:Humans; D007501:Iron / Q000097:blood*; D033862:Iron-Binding Proteins; D007668:Kidney / Q000187:drug effects / Q000503:physiopathology; D008099:Liver / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D014810:Vitamin E / Q000097:blood / Q000627:therapeutic use
D000975:Antioxidants; D033862:Iron-Binding Proteins; D014810:Vitamin E; D008315:Malondialdehyde; D005293:Ferritins; D007501:Iron; D001205:Ascorbic Acid; D002945:Cisplatin