Antioxidant-mediated effects in a gerbil model of iron overload.
BACKGROUND
Iron cardiomyopathy is a lethal complication of transfusion therapy in thalassemia major. Nutritional supplements decreasing cardiac iron uptake or toxicity would have clinical significance. Murine studies suggest taurine may prevent oxidative damage and inhibit Ca2+-channel-mediated iron transport. We hypothesized that taurine supplementation would decrease cardiac iron-overloaded toxicity by decreasing cardiac iron. Vitamin E and selenium served as antioxidant control.


METHODS
Animals were divided into control, iron, taurine, and vitamin E/selenium groups. Following sacrifice, iron and selenium measurements, histology, and biochemical analyses were performed.


RESULTS
No significant differences were found in heart and liver iron content between treatment groups, except for higher hepatic dry-weight iron concentrations in taurine-treated animals (p < 0.03). Serum iron increased with iron loading (751 +/- 66 vs. 251 +/- 54 microg/dl, p < 0.001) and with taurine (903 +/- 136 microg/dl, p = 0.03).


CONCLUSIONS
Consistent with oxidative stress, iron overload increased cardiac malondialdehyde levels, decreased heart glutathione peroxidase (GPx) activity, and increased serum aspartate aminotransferase. Taurine ameliorated these changes, but only significantly for liver GPx activity. Selenium and vitamin E supplementation did not improve oxidative markers and worsened cardiac GPx activity. These results suggest that taurine acts primarily as an antioxidant rather than inhibiting iron uptake. Future studies should illuminate the complexity of these results.
Otto-Duessel
Maya
M
Division of Radiology, Children's Hospital Los Angeles, Los Angeles, Calif 90027, USA.
Aguilar
Michelle
M
Moats
Rex
R
Wood
John C
JC
D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D001219:Aspartate Aminotransferases / Q000097:blood; D009202:Cardiomyopathies / Q000209:etiology / Q000517:prevention & control*; D004353:Drug Evaluation, Preclinical; D005260:Female; D005849:Gerbillinae; D005979:Glutathione Peroxidase / Q000032:analysis; D006321:Heart / Q000187:drug effects; D019190:Iron Overload / Q000150:complications / Q000188:drug therapy*; D007505:Iron-Dextran Complex / Q000493:pharmacokinetics / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D008315:Malondialdehyde / Q000032:analysis; D023421:Models, Animal; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D018384:Oxidative Stress; D064586:Selenic Acid; D018036:Selenium Compounds / Q000008:administration & dosage / Q000627:therapeutic use; D013654:Taurine / Q000008:administration & dosage / Q000627:therapeutic use*; D014810:Vitamin E / Q000008:administration & dosage / Q000627:therapeutic use
D000975:Antioxidants; D018036:Selenium Compounds; D014810:Vitamin E; D013654:Taurine; D008315:Malondialdehyde; D007505:Iron-Dextran Complex; D005979:Glutathione Peroxidase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D064586:Selenic Acid