FLIM58, a blocking peptide for FAS ligand, reduces apoptotic cell death of allogenic-transplanted hepatocytes in spleen

FLIM58, a Blocking Peptide for FAS Ligand, Reduces Apoptotic Cell Death of Allogenic-Transplanted Hepatocytes in Spleen E. Song, J. Chen, J. Lutz, M. Wang, and U. Heemann

H

EPATOCYTE transplantation (HTx) has been proposed as a potential therapeutic modality for various liver disorders by providing metabolic support during acute and chronic liver failure and replacing specific liver functions in inherited metabolic liver diseases. However, following allogenic hepatocyte transplantation into the spleens, the transplanted cells are rejected within a few days without immunosuppression.1 We have previously demonstrated that this is related to the expression of Fas ligand (FasL) on splenocytes, which probably mediates apoptosis of the transplanted hepatocytes by Fas and FasL interaction.2 FLIM58 is a blocking peptide for Fas ligand to interact with its receptor, FasR (CD95), and thus inhibits apoptotic cell death mediated by such interaction.3 The present study was designed to investigate the effects of FLIM58 on the survival of allogenic intrasplenically transplanted hepatocytes. MATERIALS AND METHODS Hepatocytes from Wistar rats were transplanted into spleens of Sprague-Dawley (SD) rats as described before.4 The recipients were treated with either FLIM58 (20 mg/kg body weight, intravenous, Mochida Pharmaceutical, Tokyo, Japan) or vehicle for the first 5 days after transplantation (n ⫽ 10/group). Spleens were harvested on day 21 after transplantation. Apoptosis of transplanted hepatocytes was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL, Boehringer Mannheim GmbH, Mannheim, Germany), and the number of TUNEL-positive hepatocytes exhibiting apoptotic morphology is given as a percentage. At least 1000 transplanted cells were counted. Additionally, survival of transplanted cells was evaluated by examining the level of glutamate dehydrogenase (GLDH), a specific enzyme produced by hepatocytes.4 All data are expressed as mean ⫾ SEM.

0041-1345/01/$–see front matter PII S0041-1345(00)02184-9

RESULTS

FLIM58 reduced the percentage of TUNEL-positive transplanted hepatocytes (4.0 ⫾ 0.5%) as compared to vehicle treated ones (9.4 ⫾ 0.7%) (P ⬍ .01). Additionally, FLIM58 resulted in a higher survival rate of allogenic hepatocytes in recipient spleens as determined by GLDH levels as compared to the controls (21.4 ⫾ 2.5 ␮g vs 15.8 ⫾ 2.0 ␮g) (P ⬍ .01). DISCUSSION

Blockade of Fas ligand and Fas receptor interaction by Fas ligand blocking peptide, FLIM58, can inhibit apoptosis of allogenic hepatocytes transplanted into spleens, and thus improves survival. REFERENCES 1. Mito M, Kusano M, Dawaura Y: Transplant Proc 24:3052, 1992 2. Song E, Chen J, Min J, et al: Asian J Surg 23:163, 2000 3. Miwa K, Hashimoto H, Yatomi T, et al: Int Immunol 11:925, 1999 4. Vroemen JM, Buurman WA, Schutte B, et al: Transplantation 45:600, 1988

From the Department of Medicine, Essen University Hospital, Essen, Germany; and Department of Surgery, Sun-Yat-Sen Memorial Hospital, Guangzhou, P.R. China. Supported by the Natural Scientific Research Grant from Guangdon (980098). Address reprint requests to Dr U. Heemann, University Essen Innere Medizin, Hochdruckkrankheiten, Hulfelandstr. 55, 45122 Essen, Germany.

© 2001 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010

650

Transplantation Proceedings, 33, 650 (2001)