mna-715 and Disease-Models--Animal

Renal ischaemia/reperfusion (I/R) injury and hypertension represent major alloantigen-independent risk factors contributing to the development of chronic allograft nephropathy. In a model of accelerated major histocompatibility complex-independent renal injury, we evaluated the effect of leflunomide derivate - FK778 - on the progression of accelerated nephropathy. Thirty-six uninephrectomized hypertensive transgenic (m-REN-2)-27 rats received a clip on renal pedicle for 45 minutes. Animals were treated with FK778 3 mg/kg/day (I/R 3 mg, N = 12), 10 mg/kg/day (I/R 10 mg, N = 12) or placebo (N = 12) via gavage for 16 weeks. Eighteen animals were sham-operated and treated with FK778 3 mg/kg/day (sham 3 mg, N = 6), 10 mg/kg/day (sham 10 mg, N = 6) or were untreated (sham, N = 6). Proteinuria and blood pressure were evaluated throughout and the kidneys were harvested for morphological and immunohistochemical analysis at the end of the experiment. At week 16, rats with I/R injury and FK778 treatment had lower proteinuria compared with placebo-treated rats (I/R 3 mg: 48.42 +/- 26.16, I/R 10 mg 27.28 +/- 21.86 vs. Placebo: 70.13 +/- 50.19 mg/day, P < 0.05). The untreated sham group exhibited lower proteinuria compared with FK778-treated sham groups (Sham 3 mg: 24.23 +/- 10.89; Sham 10 mg: 17.37 +/- 4.13; Sham: 14.23 +/- 1.18) There was no difference in glomerulosclerosis and interstitial fibrosis among the treated groups. In the untreated animals the rate of interstitial fibrosis decline reached statistical significance (Placebo vs. Sham: 1.125 +/- 0.641 % vs. 0.250 +/- 0.500 %, P < 0.05). There was higher CD5+ leukocyte infiltration in the placebotreated group. FK778-treated rats displayed amelioration of some changes induced by the I/R injury. Our observation also suggests potential nephrotoxicity of FK778.

Topics: Alkynes; Animals; Blood Pressure; Disease Models, Animal; Immunosuppressive Agents; Isoxazoles; Kidney; Kidney Diseases; Leflunomide; Male; Nitriles; Placebos; Rats; Rats, Transgenic; Reperfusion Injury

Acute rejection is the major risk factor for the development of subsequent chronic allograft nephropathy (CAN), which is the primary reason for late allograft loss in kidney transplantation. Platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) are the main mitogens mediating mesenchymal cell proliferation. Their early post-transplant induction may start cascades leading to the development of CAN. An immunosuppressive drug, FK778, inhibits de novo pyrimidine biosynthesis and several receptor tyrosine kinases (RTKs). Here we investigated its effects on acute and chronic rejection as well as post-transplant PDGF and TGF-beta expression in combination therapy with calcineurin inhibitors (CNIs).. Kidney transplantations were performed from DA to WF rats. Syngenic DA-DA grafts were used as controls. Allografts were immunosuppressed with a combination of FK778 (10 mg/kg/day p.o.) and CsA (1.5 mg/kg/day s.c.) or tacrolimus (Tac) (1.5 mg/kg/day p.o.). Grafts were harvested 5 and 90 days after transplantation for histology and immunohistochemistry (PDGF-A, PDGF-B, PDGFR-alpha, PDGFR-beta, TGF-beta, TGF-betaR). The dose response of FK778 on acute rejection was studied with monotherapy of 5, 10 and 20 mg/kg/day. Chronic changes were scored according to the Chronic Allograft Damage Index (CADI).. FK778 ameliorated the early post-transplant inflammatory response dose dependently. Additive effects were seen with FK778 and CNIs. Significantly lower CADI scores were seen in combination therapy of FK778 and CNIs compared with CNI monotherapies. FK778 also significantly reduced both early and late PDGF and TGF-beta expression when combined with CNIs.. These results indicate that FK778 could prevent the development of CAN and be a promising therapy also in clinical kidney transplantation.

Topics: Alkynes; Animals; Calcineurin Inhibitors; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cyclosporine; Disease Models, Animal; Dose-Response Relationship, Drug; Graft Rejection; Immunosuppressive Agents; Isoxazoles; Kidney Diseases; Kidney Transplantation; Male; Nitriles; Platelet-Derived Growth Factor; Rats; Rats, Inbred WF; Risk Factors; Tacrolimus; Transforming Growth Factor beta; Transplantation, Homologous

This study examines the efficacy of FK778 regimens for prevention of different phases of xenograft rejection.. Antibody and complement tissue depositions were measured by immunofluorescence in a discordant ex vivo rat-to-human heart perfusion model of hyperacute rejection with immunosuppressant-enriched human blood. The concordant hamster-to-rat aortic xenotransplantation model was used to assess host cellular (lymphocyte activation, mixed lymphocyte reaction [MLR]) and humoral responsiveness (xenoantibody production) as well as histologic xenograft rejection. Recipients were treated for 14 days with FK778, tacrolimus, sirolimus or combination regimens at varying doses.. Antibody binding during hyperacute rejection was unaffected by the immunosuppressive treatment, but complement deposition was reduced in the following order: tacrolimus > FK778 approximately sirolimus. FK778 most effectively reduced complement factor 5 in vitro. In untreated rats with hamster aortic xenografts, a large infiltrative response was observed within the grafts with extensive myocyte necrosis. Tacrolimus > FK778 approximately sirolimus dose-dependently diminished xenograft infiltration and in the same order reduced vessel-wall myocyte necrosis. Tacrolimus approximately FK778 > sirolimus reduced in vivo lymphocyte CD25 expression and tacrolimus > FK778 approximately sirolimus diminished MLR. Xenoreactive IgM and IgG antibody production levels were vigorously upregulated a few days after transplantation, but were significantly reduced by tacrolimus > FK778 approximately sirolimus. Combination regimens revealed no significant benefit when compared with the corresponding monotherapy groups.. FK778 mildly interfered with hyperacute rejection and markedly suppressed acute humoral and cellular aortic xenograft rejection. However, T-cell-dependent host responses were most potently suppressed by tacrolimus, and the overall efficacy of FK778 was similar to that of sirolimus.

Topics: Alkynes; Animals; Antibodies, Anti-Idiotypic; Aorta, Abdominal; Cricetinae; Disease Models, Animal; Endothelium, Vascular; Flow Cytometry; Graft Rejection; Humans; Immunoglobulin G; Immunoglobulin M; Interleukin-2 Receptor alpha Subunit; Isoxazoles; Male; Nitriles; Rats; Rats, Inbred BN; Rats, Inbred Lew; T-Lymphocytes; Transplantation, Heterologous; Treatment Outcome

The aim of this study was to assess the efficacy of FK778 to prevent acute and chronic allograft rejection compared with other immunosuppressive agents.. 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.. 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.. 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.

Topics: Acute Disease; Alkynes; Animals; Chronic Disease; Disease Models, Animal; Graft Rejection; Graft Survival; Heart Transplantation; Immunosuppressive Agents; Isoxazoles; Nitriles; Rats; Rats, Inbred BN; Rats, Inbred Lew; Sirolimus; Tacrolimus; Trachea; Transplantation, Homologous

Aim of this study was to prove the efficacy and safety of the new malononitrilamide immunosuppressive FK778 in prolonging clear graft survival following allogeneic orthotopic keratoplasty in rats.. Sixty-seven penetrating keratoplasties were performed using Fisher and Lewis rats as donors and recipients, respectively: group 1 (n=11), allogeneic control without therapy; group 2 (n=12), syngeneic control; group 3 (n=11), mycophenolate mofetil (MMF) 40 mg/kg bodyweight; group 4 (n=12), FK778 5 mg/kg bodyweight; group 5 (n=12), FK778 10 mg/kg bodyweight; and group 6 (n=9), FK778 20 mg/kg bodyweight. Four animals in each group were killed for immunohistological evaluation on day 14. Therapy was administered orally for 18 days. The grafts were evaluated every three days by means of a scoring system including opacity, oedema, and vascularization. Time to rejection was analysed with the Kaplan-Meier survival analysis and compared with the log-rank test. The densities of infiltrating immune cells were compared statistically using the non-parametric Mann-Whitney test.. Mean rejection-free graft survival was 11.4 days in group 1 (allogeneic control), 100 days (total follow-up time) in group 2 (syngeneic control), 24.0 days in group 3 (MMF 40 mg/kg), 15.7 days in group 4 (FK778 5 mg/kg), 19.1 days in group 5 (FK778 10 mg/kg), and 25.4 days in group 6 (FK778 20 mg/kg) (P<0.005).. Systemic immunosuppression with FK778 prolongs graft survival in the rat keratoplasty model. FK778's efficacy is comparable with that of MMF in preventing immunologic graft rejection.

Topics: Alkynes; Animals; Cornea; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Graft Rejection; Graft Survival; Immunosuppressive Agents; Isoxazoles; Keratoplasty, Penetrating; Mycophenolic Acid; Nitriles; Postoperative Care; Postoperative Period; Rats; Rats, Inbred F344; Rats, Inbred Lew; Survival Analysis; Treatment Outcome

Chronic allograft nephropathy (CAN) still belongs to the leading causes of graft loss over the long term. The leflunomide derivative FK778 is a novel immunosuppressant with improved pharmacokinetic properties that effectively prolonged graft survival in several transplantation models. In the present study, we investigated the effects of FK778 at different phases after transplantation on the progression of CAN.. Fisher 344 kidneys were orthotopically transplanted into Lewis recipients. Recipients were treated with FK778 (5 mg/kg/day) over different time periods (early: days 0-10 only, continuous: day 0 to week 24, or late: weeks 16-24 only posttransplantation). Proteinuria was measured every 4 weeks, whereas grafts were harvested at 24 weeks posttransplantation for morphological and immunohistochemical analysis as well as transforming growth factor-beta and platelet derived growth factor-B chain expression.. Continuous treatment with FK778 ameliorated the progression of CAN, whereas late treatment reduced proteinuria and resulted in a similar grade of CAN as compared to animals with continuous treatment. In contrast, FK778 given only during the early phase after transplantation had no effect on the progression of CAN as compared to controls.. In summary, FK778 is a potent immunosuppressive drug that can delay the progression of CAN, even when given at later stages after transplantation.

Topics: Alkynes; Animals; Creatinine; Disease Models, Animal; Disease Progression; Dose-Response Relationship, Drug; Graft Rejection; Immunosuppressive Agents; Isoxazoles; Kidney; Kidney Transplantation; Male; Nitriles; Proteinuria; Proto-Oncogene Proteins c-sis; Rats; Rats, Inbred F344; Rats, Inbred Lew; RNA, Messenger; Transforming Growth Factor beta; Transplantation, Homologous

This study examined the efficacies of sirolimus and the novel immunosuppressive agent FK778 to prevent obliterative airway disease (OAD). Tracheae from Brown-Norway donors were heterotopically transplanted in the greater omentum of Lewis rats. Recipients were treated for 28 days with sirolimus (0.5 or 2 mg/kg), FK778 (5 or 20 mg/kg), or combination regimens (0.5 + 5 mg/kg, 2 + 20 mg/kg). Tracheal segments were evaluated for degree of luminal obliteration, percentage of luminal epithelial cell coverage, and peritracheal infiltration. In vitro smooth muscle cell (SMC) proliferation and migration assays were performed to assess direct nonimmune-related effects of the drugs. Sirolimus 2 mg/kg and FK778 20 mg/kg effectively reduced graft infiltration and prevented airway obliteration, whereas FK778 5 mg/kg was insufficient. Sirolimus 0.5 mg/kg at least showed moderate inhibitory effects on luminal obliteration and graft infiltration. Combination regimens revealed no significant beneficial effects. Both sirolimus and FK778 barely showed preserved epithelial coverage. Within the range of relevant concentrations, FK778 showed more potent anti-proliferative and anti-migratory effects on SMC in vitro than sirolimus. Both agents proved effective to prevent OAD development without preserving relevant amounts of epithelium. The anti-proliferative potency on SMCs seems to be an especially important mechanism for FK778. De novo combination regimens revealed no beneficial interaction and thus remain doubtful.

Topics: Alkynes; Animals; Disease Models, Animal; Immunosuppressive Agents; In Vitro Techniques; Isoxazoles; Lung Diseases, Obstructive; Lung Transplantation; Male; Myocytes, Smooth Muscle; Nitriles; Rats; Rats, Inbred BN; Rats, Inbred Lew; Sirolimus; Trachea; Transplantation, Homologous; Transplantation, Isogeneic

To test the efficacy of limited oral administration of the new leflunomide analogue FK778 for suppression of neointima proliferation in a double-injury restenosis model in the rat.. For induction of aortic lesions, silicon cuffs were placed operatively around the infrarenal aortas of Lewis rats. After 21 days, the aortic cuffs were removed and the lesions were dilated with 2-F Fogarty catheters inserted via the left common carotid artery. The novel immunosuppressant FK778 was administered at a dose of 5 mg/kg body weight (group 1) or 15 mg/kg body weight (group 2) in a total of 38 animals. For both doses, three different periinterventional time periods, each with a 5-day course of oral FK778, were defined as follows: (i) days -2 to 2, (ii) days 1-5, and (iii) days 7-11, with six or seven rats in each group. After 3 weeks, intima/media ratios were assessed morphometrically and immunohistochemistry for quantification of intimal alpha-actin expression was performed.. In both dose groups, there was a trend toward inhibition of neointima formation when the 5-day course of FK778 was started before or 1 day after the intervention. However, in the lower-dose group, inhibition of neointima was not statistically significant regardless of the time frame of treatment (groups 1a-c). With the higher dose, suppression of intimal hyperplasia was significant when FK778 was administered between days 1 and 5 after angioplasty (group 2b; P<.01). Expression of alpha-actin in the intima of FK778-treated rats was significantly reduced when the drug was started 2 days before angioplasty in group 1a (P<.05) or 1 day after angioplasty in both dosage groups (group 1b, P<.01; group 2b, P<.05).. In the double-injury rat model presented, balloon-mediated proliferation of smooth muscle cells in the intima with consecutive intimal thickening was influenced by FK778 in a dose-dependent manner. However, long-term studies are needed to exclude a delay of vascular healing in this particular model.

Topics: Actins; Administration, Oral; Alkynes; Angioplasty, Balloon; Animals; Disease Models, Animal; Hyperplasia; Immunohistochemistry; Immunosuppressive Agents; Isoxazoles; Male; Muscle, Smooth, Vascular; Nitriles; Rats; Rats, Inbred Lew; Tunica Intima

The effectiveness of the novel immunosuppressive agent FK778 and of tacrolimus to prevent the development of obliterative airway disease (OAD) was investigated in an animal model.. Tracheae from Brown-Norway donors were heterotopically transplanted in the greater omentum of Lewis rats. Recipients were treated for 28 days with FK778 (5 or 20 mg/kg), tacrolimus (1 or 4 mg/kg) or combination regimens at varying doses (5 + 1 mg/kg, 10 + 2 mg/kg or 20 + 4 mg/kg). Grafts were harvested and processed for histologic and immunohistochemical evaluation. Lymphocyte surface antigen expression was quantified and in vitro smooth muscle cell (SMC) proliferation assays were performed.. In untreated recipients, very large amounts of infiltrating CD4+, CD8+ and ED1+ mononuclear cells were observed in the peritracheal region with epithelial loss and complete luminal obliteration. Granulation tissue consisted of alpha-actin-positive cells and collagen-rich fibrosis. FK778 and tacrolimus as well as combination regimens of both agents dose-dependently inhibited peritracheal infiltration and luminal obliteration. Only tacrolimus-treated recipients showed preserved luminal epithelial coverage with airway goblet cells, whereas, in animals that received FK778, no epithelium was found. Both agents equally suppressed in vivo lymphocyte CD25 expression. Only FK778-treated animals were completely free of adverse drug side effects. FK778 but not tacrolimus showed potent anti-proliferative effects on SMC in vitro.. Although both agents proved effective to prevent OAD development, histology revealed major differences. The anti-proliferative potency of FK778 on SMC may be an important mechanism of action. Combination regimens showed favorable drug interaction and allowed dose reduction of both agents to achieve maximal immunosuppressive efficacy.

Topics: Actins; Alkynes; Animals; Bronchiolitis Obliterans; Disease Models, Animal; Granulation Tissue; Immunosuppressive Agents; Isoxazoles; Lymphocyte Activation; Nitriles; Postoperative Complications; Rats; Rats, Inbred BN; Rats, Inbred Lew; Tacrolimus; Trachea

Topics: Acrylamide; Acrylamides; Alkynes; Animals; Antibodies, Antinuclear; Arthritis, Experimental; Arthritis, Rheumatoid; Caproates; Disease Models, Animal; Female; Immunoglobulin G; Immunosuppressive Agents; Isoxazoles; Mice; Mice, Mutant Strains; Nitriles; Rats; Rats, Inbred Lew

The use of inbred mouse strains of defined genetic background has allowed for the development of systems capable of reproducibly generating either an acute or chronic graft-versus-host disease (GvHD). The malononitrilamides MNA 279 and MNA 715, analogues of the main metabolite of leflunomide, have been shown to directly inhibit T-cell proliferation and B-cell functions. Therefore, they have been studied in a local GvH reaction in the popliteal lymph node (PLN) assay in LBN rats, on the development of an acute and lethal GvHD in B6C3F1 mice and on a chronic autoimmune GvHD in BDF1 hybrid mice. In the PLN assay an oral administration of various concentrations (7.5 to 50 mg/kg) of both MNAs inhibited the localized GvH reaction dose-dependently and suppressed the lymph node hyperplasia. Both MNAs also acted therapeutically in this assay when they were given as late as day 4 or 5 after challenge. In the model of an acute lethal GvHD the treatment of the GvH-B6C3F1 hybrid mice with the MNAs (2.5 to 20 mg/kg/day) shortly after disease induction on days 3 to 12 resulted in a dose-dependently improved survival rate. With 20 mg/kg of drugs, mortality of this life-threatening GvHD was completely prevented and also other parameters like splenomegaly, erythrocyte counts and hematocrit values were strongly suppressed. Treatment of sensitized GvH-BDF1 hybrid mice in the chronic autoimmune-like model with the MNAs (30 mg/kg/day), given on days 3 to 36 by oral gavage, resulted in an improved survival rate, inhibited lymphadenopathy and splenomegaly, reduced the levels of autoantibodies and other immunoglobulins like IgE and IgG1, prevented proteinuria and the development of glomerulonephritis. Both MNA 279 and MNA 715 can inhibit ongoing aberrant immune responses in animals suffering from GvHD.

Topics: Alkynes; Animals; Disease Models, Animal; Graft vs Host Disease; Graft vs Host Reaction; Immunosuppressive Agents; Isoxazoles; Lupus Erythematosus, Systemic; Lymph Nodes; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Nitriles; Rats; Rats, Inbred BN; Rats, Inbred Lew

Due to their immunosuppressive mode of action, we examined the therapeutic effects of the malononitrilamides MNA 279 and MNA 715 in acute EAE, and two models of chronic relapsing EAE in Lewis rats and Biozzi mice. In the first model, sensitization of adult Lewis rats with guinea pig spinal cords results in an acute clinical episode of severe EAE, and by day 15 all animals had died. Treatment of these sensitized rats with the MNAs was most effective in delaying and reducing the onset of clinical symptoms, and mortality of acute EAE was prevented in a dose-dependent manner. The protection afforded by the two MNAs was long-lasting and no subsequent relapse was observed. Similarly, in the chronic relapsing disease, aged Lewis rats were immunized with rabbit myelin basic protein, and all untreated animals developed a disease with up to three relapses. The second and third episodes were both milder and shorter in duration than the first. All animals treated with the MNAs survived the first attack, which also was delayed. Pathological signs were reduced and relapses did not occur. Inhibition of chronic relapsing EAE in aged Lewis rats was observed, even when the MNA-treatment was started after the first appearance of clinical symptoms. All treated animals recovered completely and mortality was prevented. Also in the second model of chronic relapsing EAE in Biozzi AB/H mice, MNA treated animals showed only one acute and delayed episode and no further relapses. All these results qualify both MNA 279 and MNA 715 as powerful immunosuppressants with therapeutic potential in human multiple sclerosis (MS).

Topics: Acute Disease; Alkynes; Animals; Chronic Disease; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Female; Guinea Pigs; Immunosuppressive Agents; Isoxazoles; Mice; Mice, Inbred Strains; Nitriles; Rabbits; Rats; Rats, Inbred Lew

Topics: Aging; Alkynes; Animals; Antibody Formation; Crosses, Genetic; Disease Models, Animal; Female; Graft vs Host Disease; Immunoglobulin E; Immunoglobulin G; Immunosuppressive Agents; Isoxazoles; Lupus Erythematosus, Systemic; Mice; Mice, Inbred DBA; Mice, Mutant Strains; Nitriles