title: Inhibition of host-versus-graft and graft-versus-host responses after small bowel transplantation in rats by rapamycin.
abstract: The effect of rapamycin (RAPA) on both host-versus-graft (HVG) and graft-versus-host (GVH) immune responses was examined in small bowel transplant models using strongly histoincompatible donor-recipient combinations. Normal Wistar Furth (WFu; RT-1u) recipients rejected Buffalo (BUF; RT-1b) small bowel allografts within a mean survival time (MST) of 10.5 +/- 0.5 days. Administration of RAPA (0.8 mg/kg) by continuous intravenous infusion for 14 days via an osmotic pump prolonged graft survival to 25.0 +/- 4.6 days (P = 0.01). In a second strain combination, the 12.5 +/- 2.2 day survival of Brown Norway (BN; RT-1n) small bowel allografts in Lewis (RT-1l) recipients was prolonged to 21.6 +/- 2.0 and 28.5 +/- 2.8 days by 14 days of i.v. RAPA at doses of 0.8 and 1.6 mg/kg, respectively. In this model RAPA is five times more effective than cyclosporine, which at 4.0 mg/kg prolongs BN small bowel allografts in Lewis recipients to 21.6 +/- 6.3. To isolate HVG and GVH immune responses, (BN x Lewis)F1 hybrid rats served as the graft donor or host, respectively. In the HVG model, (BN x Lewis)F1 small bowel allografts, which were rejected by normal Lewis recipients at 12.2 +/- 3.6 days, were prolonged to 40.8 +/- 5.8 days (P = 0.001) by RAPA (0.8 mg/kg x 14 days). In the GVH model, the ability of Lewis small bowel allografts to produce severe GVH disease in untreated (BN x Lewis)F1 recipients at 12.3 +/- 2.8 days was delayed to 21.3 +/- 5.2 days by 0.8 mg/kg RAPA (P = 0.025). Thus, RAPA protects small bowel allografts more effectively against HVG than GVH immune responses.
authors.affiliation: Department of Surgery, University of Texas Medical School, Houston 77030.
authors.forename: S M
authors.initials: SM
authors.lastname: Stepkowski
authors.forename: H F
authors.initials: HF
authors.lastname: Chen
authors.forename: M E
authors.initials: ME
authors.lastname: Wang
authors.forename: P
authors.initials: P
authors.lastname: Daloze
authors.forename: B D
authors.initials: BD
authors.lastname: Kahan
mesh_terms: D000818:Animals; D001835:Body Weight; D016572:Cyclosporine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006085:Graft Survival; D006087:Graft vs Host Reaction / Q000187:drug effects* / Q000276:immunology; D006789:Host vs Graft Reaction / Q000187:drug effects* / Q000276:immunology; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007408:Intestinal Absorption; D007421:Intestine, Small / Q000637:transplantation*; D008297:Male; D008320:Maltose / Q000378:metabolism; D011090:Polyenes / Q000494:pharmacology*; D051381:Rats; D011914:Rats, Inbred BN; D011915:Rats, Inbred BUF; D011917:Rats, Inbred Lew; D011920:Rats, Inbred WF; D020123:Sirolimus; D014184:Transplantation, Homologous / Q000276:immunology
chemical_list: D007166:Immunosuppressive Agents; D011090:Polyenes; D008320:Maltose; D016572:Cyclosporine; D020123:Sirolimus