Synergistic effect of vincristine with tacrolimus or sirolimus in prevention of acute heart allograft rejection in the rat

The application of multiple immunosuppressive therapy for organ transplantation could enhance therapeutic efficacy, while minimizing the toxicity of individual drugs used in the regimen. In this study, the effect of the combined therapy of vincristine (VCR) with tacrolimus (FK506) or sirolimus (rapamycin, RAPA) was tested in prevention of acute heart allograft rejection in the rat. A Brown Norway (BN, RT 1(n)) to Lewis (LEW, RT 1(1)) rat combination was used in a heart allografting model. VCR was administered intraperitoneally once daily, while FK506 and RAPA were given by gavage once daily for 14 days after transplantation. There were dose-related prolongations of mean survival time (MST) to monotherapy of VCR, FK506, or RAPA. The MST in combination therapy indicated that a synergistic interaction was produced when compared with the respective monotherapies: VCR 0.05 mg/kg/day + FK506 0.5 mg/kg/day (16.00 +/- 1.79 days, P = 0.001; combination index (CI) = 0.557); VCR 0.05 mg/kg/day + FK506 1.0 mg/kg/day (29.00 +/- 10.54 days, P = 0.001; CI = 0.598); VCR 0.05 mg/kg/day + RAPA 0.2 mg/kg/day (17.33 +/- 1.97 days, P = 0.001; CI = 0.500); and VCR 0.05 mg/kg/day + RAPA 0.4 mg/kg/day (21.17 +/- 3.19 days, P = 0.001; CI = 0.838). Combination therapy of VCR and FK506 or RAPA produced synergistic effects in prevention of acute heart allograft rejection in the rat.     

Sirolimus rescue therapy for refractory rejection in renal transplantation.

BACKGROUND: Acute renal allograft rejection episodes refractory to antilymphocyte preparations almost inevitably progress to transplantation loss. To reverse ongoing rejection processes, we administered sirolimus (RAPA) after failure of conventional immunosuppressive regimens including full courses of antilymphocyte sera. METHODS: All 36 renal transplantation recipients reported herein displayed either Grade IIB or Grade III biopsy-proven (Banff 1993 criteria) ongoing rejection episodes despite prior treatment with pulse and/or oral recycling of steroids and at least one 14- to 21-day course of murine (OKT3) or equine (ATGAM) antilymphocyte treatment. We compared the actual 12-month outcomes of two demographically similar cohorts of patients treated for refractory rejection with RAPA (Group I; n=24) or mycophenolate mofetil (MMF; Group II; n=12) added to a baseline regimen of cyclosporine (CsA)/prednisone (Pred). RESULTS: Rescue therapy reversed the renal dysfunction in 96% of patients in the RAPA group versus 67% in the MMF group (P=0.03) despite the fact that a greater fraction of patients in the RAPA (17 of 24) than the MMF group (6 of 12) had experienced two or more episodes of acute rejection before study entry and the fact that the recurrent bouts of acute rejection occurred within the first 6 months posttransplant in 94% of patients in the RAPA group compared with 50% (P=0.005) in the MMF group. Among the patients who were reversed successfully, the rates of rebound acute rejection were similar (4% vs. 8%). The mean serum creatinine values were slightly, although not significantly, lower among RAPA than MMF patients at 1, 3, 6, and 12 months: namely, 2.6 vs. 2.8, 2.8 vs. 3.2, 3.0 vs. 3.3, and 2.8 vs. 3.2 mg/dL, respectively. The 1-year patient and graft survival rates were similar: namely, 88% vs. 92% and 83% vs. 67% for the RAPA versus MMF groups. CONCLUSION: RAPA is a potent immunosuppressive agent for the treatment of refractory renal allograft rejection.     

Coadministration of the new macrolide immunosuppressant RAD and mycophenolate mofetil in experimental corneal transplantation

INTRODUCTION: The effect of RAD, a new macrolide immunosuppressant, was examined as mono- and combination therapy with mycophenolate mofetil (MMF) in prevention of acute allograft rejection in murine corneal transplantation. METHODS: Both drugs were administered orally for 18 days beginning at the day of transplantation. The inbred strains Fisher and Lewis were used as donors and recipients, respectively. Five groups were involved: syngeneic control, allogeneic control, 2.5 mg/kg RAD, 40 mg/kg MMF, and double drug therapy with 1.5 mg/kg RAD and 20 mg/kg MMF. RESULTS: The median transplant survival time in the allogeneic combination was 12 (+/-0.3) days. Monotherapy with 2.5 mg/kg RAD and 40 mg/kg MMF led to a statistically significant prolongation of transplant survival to 25.5 (+/-12.5, P=0.0001) days and 19.5 (+/-13.9, P=0.0053) days, respectively. Combination therapy was superior to both monotherapies (100+/-15.8 days, P=0.03). There was a significant reduction in the number of CD4+, CD8+, as well as CD45RA+ cells in the RAD- and double drug-treated animals when compared with the allogeneic control. This significant reduction in graft-infiltrating lymphocytes has not been found in the MMF monotherapy. CONCLUSIONS: The unique finding of this first study on the combination of RAD and MMF in murine corneal transplantation is that double drug therapy produces a highly synergistic effect in prevention of acute allograft rejection without a higher incidence of complications related to drug toxicity or overimmunosuppression.     

Rapamycin, mycophenolate mofetil, methylprednisolone, and cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin-based conditioning regimen to induce partial tolerance to hind limb allografts without cytoreductive conditioning

BACKGROUND: Composite tissue allograft transplantation may represent the next frontier in the field of reconstructive surgery. However, the main obstacles precluding the routine use of composite tissue allotransplants are rejection and toxicity associated with life-long immunosuppressive therapy. In this study, we investigated a nontoxic immunosuppressant and cytotoxic T-lymphocyte-associated antigen 4 immunoglobulin (CTLA4-Ig)-based protocol to induce donor-specific tolerance to hind limb allografts in rats. METHODS: Fully mismatched, 4- to 10-week-old Brown Norway (BN, RT1n) and Lewis (RT1) rats were used as cell/organ donors and recipients, respectively. Recipients were treated with CTLA4-Ig (2 mg/kg/d) on days -30, -28, -26, -24, and -22, rapamycin, mycophenolate mofetil, and methylprednisolone (RAPA/MMF/MP) combined therapy (from days -30 to day 100), a single dose of anti-lymphocyte serum (10 mg, on day -30), and donor bone marrow (10 x 10(7) T-cell-depleted cells) transplantation (BMT, on day -30). Thirty days after BMT, chimeric animals received hind limb allotransplantations (on day 0). The RAPA/MMF/MP combined therapy was changed to Cyclosporine (CsA, 8 mg/kg/d) on day 100 and maintained thereafter at this level. RESULTS: Hematopoietic chimerism of 17.6 +/- 9.5% at day 0, was stable (15.2 +/- 5.6%) at 230 days post-BMT; there was no sign of graft-versus-host disease. Chimeric recipients (Lewis) permanently accepted (>200 days) donor (BN)-specific (RT11, n = 6) hind limbs, yet rapidly rejected (20 +/- 2 days) third-party hind limbs (Wistar Furth [WF]). Lymphocytes of graft-tolerant animals demonstrated hyporesponsiveness in mixed lymphocyte cultures in a donor-specific manner. Tolerant graft histology showed no signs of acute and chronic rejection. CONCLUSIONS: The immunosuppressant and CTLA4-Ig-based conditioning regimen with donor BMT produced mixed chimerism and induced partial donor-specific tolerance to hind limb allografts.     

Evidence that rapamycin rescue therapy delays rejection of major (MHC) plus minor (non-MHC) histoincompatible heart allografts in rats.

The capacity of delayed onset of rapamycin (RAPA) therapy to block process of destruction was examined in rats undergoing heart allograft rejection. Untreated Wistar Furth (WFu; RT-1u) recipients reject Buffalo (BUF; RT-1b) heart allograft with a mean survival time (MST) of 6.5 +/- 0.5 days. A 14-day i.v.infusion of 0.8 mg/kg RAPA begun on the day of transplantation prolonged the survival to 74.1 +/- 20.2 days (P < 0.001), 0.2 mg/kg to 32.2 +/- 10.0 days (P < 0.001), and 0.08 mg/kg to 36.4 +/- 11.8 days (P < 0.001). When RAPA therapy (0.8 mg/kg) was begun 3 or 4 days after transplantation, the grafts survived 85.2 +/- 31.1 (P < 0.001), and 70.2 +/- 43.3 (P < 0.005) days, respectively. Therapy initiated on day 5 was much less effective; most transplants were rejected within 10 days; one graft survived 32 and two grafts 60 days (MST = 17.6 +/- 20.0, NS). A 0.2 mg/kg RAPA dose prolonged graft survival with initial use on days 3 (31.6 +/- 12.2 days; P < 0.001) or 4 (31.4 +/- 8.1 days; P < 0.001) but not on day 5. The 0.08 mg/kg RAPA prolonged hearts only when started on day 3 (47.2 +/- 2.7 days; P < 0.001) but not on days 4 or 5. WFu recipients treated with a subtherapeutic dose of cyclosporine (1 mg/kg; 9.1 +/- 1.5 days) displayed prolonged heart allograft function when treated subsequently with RAPA (0.8 or 0.08) beginning from days 4, 5, or 6 postgrafting. These in vivo results are supported by in vitro experiments. The frequency of BUF alloreactive elements among normal WFu LN cells (fTc) was 337 +/- 139/10(6) T cells in limiting dilution assay. Addition of RAPA (1 muMol) at the beginning of culture significantly reduced (P < 0.025) the fTc to 17 +/- 6.6/10(6), or alternatively on days 4 or 6 to 37.3 +/- 20.0/10(6) and 58.6 +/- 21.8/10(6), respectively. Thus, both in vivo and in vitro data demonstrate that delayed RAPA therapy may interrupt alloimmune reactions.     

Treatment of early mixed cellular and humoral renal allograft rejection with tacrolimus and mycophenolate mofetil

This prospective study investigated the efficiency of the tacrolimus (Tac) combined with mycophenolate mofetil (MMF) alone without immunoadsorption (IA) or plasmapheresis (PPH) as treatment for early (within 2 weeks) acute humoral rejection (AHR) in non-sensitized renal allograft recipients. Of 160 patients enrolled in this prospective study, 11 patients had histologically and clinically confirmed early steroid-resistant acute rejection with an antibody response and received Tac-MMF therapy. No other aggressive rescue methods such as IA, PPH were used, according to the study design. Patients (n=11) were followed for 13.8+/-3.5 months; nine were females. The complement-dependent cytotoxicity crossmatch was negative before transplantation in all patients and only positive for panel-reactive antibody in one patient. Most of the rejection episodes were mixed with cellular rejection (four patients met Banff IIA criteria, five patients met Banff IIB, one patient met Banff IB, and one patient met Banff borderline). After 16.19+/-6.16 days of treatment, all rejection episodes were successfully reversed and all graft functions were stable, with a mean serum creatinine level of 1.12+/-0.32 mg/dl during follow-up. No patient suffered from severe infectious complications (except one case of urinary infection). Our investigation suggests that Tac combined with MMF alone is adequate to reverse early mixed cellular and humoral C4d-positive rejection in non-sensitized renal allograft recipients.     

Combined use of the JAK3 inhibitor CP-690,550 with mycophenolate mofetil to prevent kidney allograft rejection in nonhuman primates

BACKGROUND: Immunosuppression via Janus kinase (JAK) 3 inhibition affords significant prolongation of allograft survival. We investigated the effects of an immunosuppressive regimen combining the JAK3 inhibitor CP-690,550 with mycophenolate mofetil (MMF) in nonhuman primates (NHPs). METHODS: Life-supporting kidney transplantations were performed between ABO-compatible, MLR-mismatched NHPs. Animals were treated orally twice a day with CP-690,550 and MMF (n=8) or MMF alone (n=2) and were euthanized at day 90 or earlier due to allograft rejection. RESULTS: Mean survival time (+/-SEM) in animals treated with MMF alone (23+/-1 days) was significantly extended in animals that concurrently received CP-690,550 (59.5+/-9.8 days, P=0.02). Combination animals exposed to higher levels of CP-690,550 had a significantly better survival (75.2+/-8.7 days) than animals that received less CP-690,550 (33.3+/-12.6 days, P=0.02). Three combination therapy animals were euthanized at day 90 with a subnormal renal function and early-stage acute graft rejection. Rejection, delayed by treatment, ultimately developed in other animals. Anemia and gastrointestinal intolerance was seen in combination therapy animals that otherwise did not show evidence of viral or bacterial infection besides signs consistent with subclinical pyelonephritis (n=3). One incidental lymphosarcoma was noted. CONCLUSIONS: Addition of CP-690,550 to MMF significantly improved allograft survival. The observed side effects appear amenable to improvements upon alteration of dosing strategies. Efficacy of this combination regimen suggests that it could become the backbone of calcineurin inhibitor-free regimens.     

Inhibition of host-versus-graft and graft-versus-host responses after small bowel transplantation in rats by rapamycin.

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.     

Decrease of apoptosis rate in patients with renal transplantation treated with mycophenolate mofetil.

BACKGROUND/AIMS: Mycophenolate mofetil (MMF) is a powerful immunosuppressant that inhibits the proliferation of lymphocytes by blocking the enzyme inosine monophosphate dehydrogenase. MMF prevents acute graft rejection in organ transplants. The aim of this investigation is to study whether MMF has any influence on apoptosis and proliferation rates of cells other than lymphocytes. METHODS: We conducted a retrospective study of renal allograft biopsies taken during the 1st week after transplantation in 25 patients receiving triple therapy with prednisone, ciclosporin and azathioprine 75 mg/day and in 25 patients treated with MMF at a dose of 2 g/day instead of azathioprine, in order to investigate the differences in the proliferation and apoptosis rates of the glomerular, tubular, interstitial and endothelial cells of the kidney. Twelve normal kidneys were used as controls. Conventional histopathological techniques were applied as usual for pathological diagnosis. Proliferative activity was assessed by use of MIB-1 antibody. Sections of formalin-fixed, paraffin-embedded tissue blocks were stained for the presence of apoptotic cells by TUNEL assay. Evaluation of proliferative or apoptotic rates was made by counting the number of positive cells in 10 glomeruli and in 10 transversely cut tubuli in each biopsy. The positive cells in the interstitium were counted in ten high-power fields. Positive cells in the endothelium were scored semiquantitatively from 0 to 3: 0 = none, 1 = isolated cells, 2 = small groups of cells, 3 = most endothelial cells. Mann-Whitney U and chi-square tests were used for intergroup comparisons. RESULTS: All biopsies were normal or had borderline (Banff classification) acute rejection. MIB-1 rates were similar in both groups, without statistical differences (p > 0.05) between them. Significantly lower apoptotic rates were found in the group treated with MMF in tubular epithelium (23.41 +/- 8.86 vs. 57.4 +/- 13.42; p = 0.021), in glomerular (1.25 +/- 0.78 vs. 5.3 +/- 1.66; p = 0.027), and interstitial cells (1.58 +/- 0.6 vs. 5.8 +/- 1.54; p = 0.043). Apoptosis in endothelial cells (p > 0.05) was similar in both groups. CONCLUSION: We conclude that treatment with MMF of kidney transplant patients does not affect the proliferative rate of cells of the allograft, but decreases the number of apoptotic cells in tubular epithelium.     

Is the malononitrilamide FK778 better for the prevention of acute or chronic rejection?

OBJECTIVE: The aim of this study was to assess the efficacy of FK778 to prevent acute and chronic allograft rejection compared with other immunosuppressive agents. MATERIALS AND METHODS: Heterotopic Brown-Norway (BN)-to-Lewis rat cardiac transplantations and heterotopic BN-to-Lewis tracheal transplantations were performed to study acute heart rejection and the development of chronic obliterative airway disease (OAD), respectively. Recipients were treated with FK778, tacrolimus, MMF, or sirolimus for 10 days (acute rejection study) or 28 days (chronic OAD study) at varying doses. RESULTS: In untreated recipients, cardiac allograft survival was 6.2 +/- 0.4 days. FK778 (20 mg/kg), tacrolimus (2 or 8 mg/kg), mycophenolate mofetil (MMF; 40 mg/kg), or sirolimus (0.5 or 2 mg/kg) significantly prolonged graft survival to 17.0 +/- 2.8, 18.5 +/- 2.7, 25.0 +/- 2.5, 20.7 +/- 3.8, 14.5 +/- 2.2, and 23.2 +/- 1.5 days, respectively (P < .05). Tracheal grafts in untreated recipients showed intense infiltration and complete luminal obliteration by day 28. FK778 (20 mg/kg), tacrolimus (1 or 4 mg/kg), MMF (10 or 40 mg/kg), or sirolimus (0.5 or 2 mg/kg) significantly inhibited tracheal luminal obliteration (19.5% +/- 16.4%, 44.2% +/- 33.6%, 12.3% +/- 3.3%, 61.7% +/- 18.6%, 18.3% +/- 11.3%, 55.0% +/- 30.9%, and 8.5% +/- 3.5% (P < .05). All 4 high-dose groups showed similar efficacy. CONCLUSIONS: When used in therapeutic doses, tacrolimus and sirolimus were more effective than FK778 to prolong cardiac allograft survival. However, with its antiproliferative effects on smooth muscle cells, its good tolerability, and its blockade of cytomegalovirus replication, FK778 proved effective to prevent chronic OAD development. Thus, FK778 may acquire an important role in maintenance therapy for the prevention of long-term fibroproliferative complications.     

霉酚酸酯与雷帕霉素合用预防及逆转大鼠心脏移植排斥反应

目的 评价霉酚酸酯（ＭＭＦ）与雷帕霉素（ＲＡＰＱ）合用预防及逆转大鼠心脏移植后排斥反应的作用。方法 将实验动物随机分为４组：（１）对照组;（２）单用ＭＭＦ组;（３）单用ＲＡＰＡ组;（４）ＭＭＦ与ＲＡＰＡ合用组。结果 单用ＭＭＦ和单用ＲＡＰＡ组与对照组比较均显著延长移植心脏存活时间,ＭＭＦ与ＲＡＰＡ合用组与对照组比较非常显著地延长移植心脏存活时间,并且心脏存活时间明显长于同剂量两药的单用组。     

骁悉和环孢素-A预防肾移植术后早期急性排斥反应

目的 探讨骁悉和环孢素－Ａ预防肾移植术后早期急性排斥反应的效果。方法 回顾性分析１９９７年１２月￣１９９９年１月临床资料完整肾移植患者１４６例,随访时间６￣１６个月。根据应用免疫抑制剂方案的不同分为硫唑嘌呤（Ａｚａ）组（环孢素－Ａ、泼尼松龙、Ａｚａ）和骁悉（ＭＭＦ）组（环孢素－Ａ、泼尼松、ＭＭＦ）。其中Ａｚａ组７８例,ＭＭＦ组６８例。所有受者术前行人类白细胞抗原（ＨＬＡ）配型,ＨＬＡ错配≤３个位点     

Synergistic effect of rapamycin and cyclosporine in prevention of acute kidney allograft rejection in the mouse

The effect of rapamycin (RAPA) and cyclosporine A (CsA) monotherapy and combination therapy was examined in prevention of kidney allograft rejection in the mouse. Both drugs were administered orally for up to 14 days in BALB/c (H-2(d)) to C57BL/6 (H-2(b)) mice strong combination. Six groups were treated with RAPA and/or CsA. This study shows that concomitant therapy of RAPA and CsA produces strong synergistic interaction in prolonging renal allograft survival in mice when compared with monotherapy of RAPA or CsA.     

Anti-LFA-1 alpha reduces the dose of cyclosporin A needed to produce immunosuppression in heterotopic cardiac transplanted rats.

BACKGROUND: Monoclonal antibodies (MAb) against cell adhesion molecules prolong the time to acute rejection of transplanted organs in animals. Postulated mechanisms of action include blockade of trafficking of host leukocytes into or recognizing of effector/target cells within the allograft. We examined whether an anti-ICAM-1 (1A29), anti-LFA-1 alpha (WT.1), or anti-CD-18 (WT.3) could reduce the immunosuppressive dose of cyclosporin A (CsA) when used in combination. METHODS: A rat heterotopic cardiac transplant model with ACI donors and Lewis recipients was used. MAb dose was 3 mg/kg, i.p. with treatment on Days -3 and -1 prior to transplant, followed by daily dosing for 10 days post-transplantation (Tx). Cyclosporin A doses were either 1.5 or 2.75 mg/kg, PO beginning the day of and for 10 days post-Tx. RESULTS: Untreated allografted rats demonstrated a mean rejection time (MRT) +/- SEM of 8.8 +/- 0.6 days. Cyclosporin A at 1.5 and 2.75 mg/kg showed mean rejection times of 8.5 +/- 0.3 (NS) and 20.5 +/- 1.9 (p < 0.05) days, respectively. Monotherapy with 1A29 or WT.3 did not prolong MRT, whereas WT.1 increased MRT to 21.7 +/- 4.3 days (p < 0.05). MAb combination therapy did not extend MRT greater than that demonstrated by WT.1 alone. However, MAb and CsA combination therapy significantly increased MRT with WT.1 and CsA resulting in the greatest extension. WT.1 combination with CsA at 1.5 mg/kg and 2.75 mg/kg increased MRT to > 46.8 +/- 6.3 and > 44.2 +/- 9.4 days, respectively. CONCLUSIONS: Anti-LFA-1 alpha and CsA combination therapy significantly extends the time to rejection of transplanted rat hearts. We conclude that combining an anti-LFA-1 alpha and CsA may be beneficial in prolonging allograft rejection times and in reducing the amount of CsA necessary for immune suppression, thereby minimizing its toxic effects.     

C4d-positive acute humoral renal allograft rejection: rescue therapy by immunoadsorption in combination with tacrolimus and mycophenolate mofetil

OBJECTIVE: We investigated the efficacy of immunoadsorption (IA) in combination with tacrolimus (FK506) and mycophenolate mofetil (MMF) rescue therapy for C4d-positive acute humoral rejection (AHR) of renal transplants. METHODS: Six of 185 cadaveric renal allograft recipients developed AHR at a mean of 4.8 +/- 0.8 days after the operation. C4d deposits were observed in peritubular capillaries (PTC) with accumulation of granulocytes. IA with staphylococcal protein A and FK506-MMF combination therapy were administered. RESULTS: After treatment with IA for 6.3 +/- 1.03 sessions combined with FK506 (0.14 to 0.16 mg.kg(-1).d(-1)) and MMF (1.5 g/d) therapy, renal function recovered in all the patients. The mean duration of treatment to a serum creatinine decrease was 14 +/- 2.9 days. The pre-IA panel reactive antibody reactivity (PRA) peaked at 50.2% +/- 6.1%, and was significantly reduced to 8.3% +/- 2.9% after IA. In four of six patients repeat allograft biopsy revealed a remission of AHR. With a mean follow-up of 18.8 +/- 5.46 months, patient and allograft survival are 100% and renal function remains stable with a mean serum creatinine of 1.2 +/- 0.22 mg/dL. CONCLUSION: The optimal treatment for alloantibody-mediated AHR remains uncertain. Our findings suggest that a therapeutic approach combining IA and FK506-MMF rescue improves the outcome of AHR.     

Conversion from cyclosporine A to mycophenolate mofetil protects recipient kidney and prevents intimal hyperplasia in rat aortic allografts

BACKGROUND: Recent studies have demonstrated that complete conversion from cyclosporine A (CsA) to mycophenolate mofetil (MMF) prolongs graft survival in patients undergoing clinical organ transplantation. We investigated the effects of conversion from CsA to MMF on recipient kidneys and transplant arteriosclerosis in a rat aortic allograft model as a high responder combination. METHODS: DA (MHC haplotype, RT1a) rat abdominal aortic grafts were orthotopically transplanted into Lewis (RT1l) rats. The recipients were divided into four oral treatment groups: (1) vehicle group, (2) CsA group (15 mg/kg/day), (3) CsA/MMF40 group (conversion from CsA 15 mg/kg/day to MMF 40 mg/kg/day on day 14), and (4) CsA/MMF20 group (conversion from CsA 15 mg/kg/day to MMF 20 mg/kg/day on day 14). On day 28 after transplantation, the rats were sacrificed and the hematoserological parameters were analyzed. The grafted aortas and recipient kidneys also were evaluated histologically and immunohistochemically. RESULTS: The CsA group developed serological renal dysfunction, arteriolar hyalinosis, and apoptosis in the recipient kidneys, whereas the CsA/MMF40 and CsA/MMF20 groups did not. In the vehicle group, we observed remarkable intimal hyperplasia and marked inflammatory cell infiltration including macrophages and T cells. In the CsA group, intimal hyperplasia was evident without infiltration of macrophages or T cells. In the CsA/MMF40 and CsA/MMF20 groups, intimal hyperplasia was abrogated, while adventitial infiltration of and adhesion to the endothelium by macrophages and T cells occurred. CONCLUSIONS: Conversion from CsA to MMF protected recipient kidneys and prevented transplant arteriosclerosis. However, insufficient immunosuppression by MMF might reactivate immune cells. This conversion therapy has preventive potential in transplant patients with CsA-associated nephrotoxicity and transplant arteriosclerosis.     

Beneficial effect of thalidomide and ciclosporin combination in heterotopic cardiac transplantation in rats

The effect of thalidomide on the prevention of early rejection was studied in heterotopic cardiac transplants between ACI (donors) and Lewis (recipients) rats, in combination with subtherapeutic doses of ciclosporin. Although allografts treated solely with thalidomide (5 mg/kg/day intraperitoneally) survived longer than controls (9.4 +/- 2.7 and 6.3 +/- 0.6 days, respectively, p less than 0.001), the survival rates of animals treated with low dose ciclosporin (1.25 mg/kg/day intraperitoneally) plus thalidomide (1.25, 2.5 and 5 mg/kg/day) were significantly better at 21 days (70, 88.9 and 88.9%, respectively), compared to 55.6% in those treated with ciclosporin (1.25 mg/kg/day) alone. Graft survival rates at 90 days were not significantly different in the thalidomide-ciclosporin combination groups (60, 77.8 and 55.6%, respectively) compared to the ciclosporin group alone (55.6%). We conclude that thalidomide is effective in preventing early rejection of rat cardiac allograft when combined with subtherapeutic doses of ciclosporin, thus avoiding the dose-dependent side effects of ciclosporin in the early posttransplant period.     

Novel rescue therapy for C4d-positive acute humoral renal allograft rejection

OBJECTIVE: To investigate the efficacy of immunoadsorption (IA) in combination with tacrolimus (TAC) and mycophenolate mofetil (MMF) rescue therapy for C4d-positive acute humoral rejection (AHR) of renal transplants. METHODOLOGY: Six of 185 cadaveric renal allograft recipients transplanted at our institute developed AHR over a mean period of 4.8 +/- 0.8 d after operation. The ages ranged from 35 to 51 yr (mean 42.6 +/- 5.6 yr). C4d deposits in peritubular capillaries (PTC) and accumulation of granulocytes in PTC were observed. IA with staphylococcal protein A and TAC-MMF combination therapy were given. RESULTS: After subjected to IA for 6.3 +/- 1.03 sessions combined with TAC (0.14-0.16 mg/kg/d) and MMF (1.5 g/d) therapy, renal function recovered in all the patients. The mean duration of treatment when serum creatinine decreased was 14 +/- 2.9 d. The pre-IA panel reactive antibody reactivity was as high as 50.2 +/- 6.1%, and was significantly reduced to 8.3 +/- 2.9% after IA. Repeated allograft kidney biopsy in four of six patients revealed a favorable remission of AHR. With a mean follow-up of 18.8 +/- 5.46 months, patient and allograft survival are 100%, renal function remained stable with a mean serum creatinine of 1.2 +/- 0.22 mg/dL. CONCLUSION: The optimal treatment for alloantibody-mediated AHR remains undefined. Our findings suggest that a therapeutic approach combining IA and TAC-MMF rescue has excellence to improve the outcome of AHR.     

Rapamycin, a potent immunosuppressive drug for vascularized heart, kidney, and small bowel transplantation in the rat

The effectiveness of rapamycin (RAPA) was examined for heart, kidney, and small bowel allografts in rats. Untreated or vehicle only-infused Wistar Furth (RT1u) recipients rejected Buffalo (RT1b) heart allografts within a mean survival time (MST) of 6.5 +/- 0.5 and 6.3 +/- 0.5 days, respectively. In contrast, a 14-day continuous intravenous (i.v.) infusion by an osmotic pump of 0.08 mg/kg/day RAPA to WFu recipients prolonged BUF heart allograft survival to an MST of 34.4 +/- 12.1 days (P = 0.0001). There was a graded dose-response to 0.16 mg/kg (39.0 +/- 8.7 days; P = 0.0001), 0.32 mg/kg (55.7 +/- 3.3 days; P = 0.0001) and 0.8 mg/kg (48.0 +/- 3.6; P = 0.0001). Furthermore, intraarterial/intragraft but not i.v. infusion of 0.02 mg/kg/day prolonged BUF heart allografts--namely, an MST of 14.6 +/- 1.4 days versus 8.6 +/- 2.6 days (P = 0.0001), respectively. Local delivery doses of RAPA were about as effective as the same dose delivered i.v.: 0.08 mg/kg MST 37.0 +/- 18.3 days (P = 0.0001); 0.32 mg/kg, 40.0 +/- 3.9 days (P = 0.0001); and 0.8 mg/kg, 54.8 +/- 8.2 days (P = 0.0001). Systemic i.v. RAPA therapy with 0.08 or 0.8 mg/kg/day prolonged the survival of BUF kidney grafts in WFu recipients--namely, an MST of 52.7 +/- 42.7 (NS) and 90.2 +/- 62.4 (P = 0.001) days, respectively, versus an MST of 11.6 +/- 1.5 days in control WFu recipients only infused with vehicle. While normal WFu rats reject heterotopic BUF small bowel allografts within an MST of 10.0 days, a 14-day course of i.v. RAPA treatment significantly (P = 0.0001) prolonged small bowel allograft survival to an MST of 26.8 +/- 3.7 days.