Blood levels of TGFbeta1 in liver transplant recipients receiving either tacrolimus or micro-emulsified cyclosporine.
BACKGROUND
Transforming growth factor beta-1 (TGFbeta1) is pro-fibrotic in addition to being a potent immunosuppressive cytokine. Cyclosporine (cyclosporin A[CsA]) has been found to increase circulating TGFbeta1 levels in patients (1, 2). To determine whether tacrolimus (FK506) similarly increases TGFbeta1 we have measured TGFbeta levels in blood samples from liver graft recipients who were of known TGFbeta1-responder status.


METHODS
Sequential serum and plasma samples were obtained from liver transplant recipients in the UK trial of tacrolimus versus microemulsified CsA, with a follow up period of between 50 and 265 days. Twelve patients received CsA and 13 received tacrolimus. Active and total TGFbeta1 protein were measured and plasma beta thromboglobulin (betaTG) levels were used as an indirect indication of platelet-derived TGFbeta contamination of samples.


RESULTS
We found no correlation between trough drug levels and active TGFbeta1 levels in serum of either set of patients. Plasma beta thromboglobulin was detected in platelet-depleted plasma samples, indicative of platelet damage before plasma separation.


CONCLUSIONS
Neither CsA nor tacrolimus induced active TGFbeta1 blood levels in liver transplant recipients during a follow up period of < or = 265 days.
Hughes
J R
JR
University of Bath, School of Biology and Biochemistry, UK.
Hughes
V F
VF
Trull
A K
AK
Metcalfe
S M
SM
D015331:Cohort Studies; D016572:Cyclosporine / Q000097:blood / Q000494:pharmacology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood / Q000494:pharmacology*; D016031:Liver Transplantation / Q000276:immunology*; D016559:Tacrolimus / Q000097:blood / Q000494:pharmacology*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000097:blood*
D007166:Immunosuppressive Agents; D016212:Transforming Growth Factor beta; D016572:Cyclosporine; D016559:Tacrolimus