Effects of antioxidant supplementation on blood cyclosporin A and glomerular filtration rate in renal transplant recipients.
BACKGROUND
Transplant recipients have elevated oxidative stress, which has prompted suggestions that supplementary antioxidants may be beneficial. However, only a small number of clinical trials have investigated antioxidant supplementation in transplant recipients, with very few data on their effects on patients' immunosuppressive therapy.


METHODS
A randomized placebo-controlled single-blind crossover trial was conducted in 10 renal transplant recipients (RTRs) taking cyclosporin A (CsA) as part of their immunosuppressive therapy. Each phase of the trial lasted 6 months, with a 6 month wash-out period in between. During one of the phases, patients consumed a tablet twice per day which delivered 400 IU/day of vitamin E, 500 mg/day of vitamin C and 6 mg/day of beta-carotene.


RESULTS
During antioxidant supplementation, there was no change in CsA dose. Antioxidant supplementation resulted in a significant decrease (P<0.05) in blood trough CsA by 24% (mean+/-SD, pre- 127.3+/-38.9, post- 97.2+/-30.7 microg/ml) compared with no change while taking the placebo (pre- 132.2+/-50.6, post- 138.6+/-56.0 microg/ml). The glomerular filtration rate was significantly (P<0.05) improved by 12% during antioxidant supplementation (pre- 66.9+/-20.7, post- 75.0+/-20.1 ml/min/1.72 m2), with no change during the placebo phase (pre- 66.8+/-11.8, post- 66.7+/-16.1 ml/min/1.72 m2). There were no significant differences (P>0.05) in markers of oxidative stress (malondialdehyde, susceptibility of plasma to oxidation) or plasma antioxidant enzymes.


CONCLUSIONS
In CsA-treated RTRs, antioxidant supplementation decreased blood CsA, which may affect adequacy of immunosuppression.
School of Human Movement Studies, The University of Queensland, Queensland, Australia.
Melanie L
ML
Blackhall
Robert G
RG
Fassett
James E
JE
Sharman
Dominic P
DP
Geraghty
Jeff S
JS
Coombes
D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use*; D002784:Cholesterol / Q000097:blood; D018592:Cross-Over Studies; D016572:Cyclosporine / Q000097:blood* / Q000627:therapeutic use; D019587:Dietary Supplements; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000276:immunology / Q000502:physiology*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D010919:Placebos
D000975:Antioxidants; D007166:Immunosuppressive Agents; D010919:Placebos; D008315:Malondialdehyde; D016572:Cyclosporine; D002784:Cholesterol