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PubMed2001

Reducing adverse effects of immunosuppressive agents in kidney transplant recipients.

Success in solid organ transplantation with minimal complications can now be achieved for most patients, and a remarkable rate of graft and patient survival can also be expected. However, the potential for adverse events and comorbid conditions increases with longer graft survival. Although the immunosuppressive regimen is central to the outcome of the transplant recipient and directly impacts the survival of the graft, chronic use of immunosuppressive agents is associated with metabolic disturbances such as hypertension, hyperlipidemia, loss of bone density, nephrotoxicity, and diabetes, which may contribute to other comorbid conditions. In addition, changes in appearance, gingival hyperplasia, hirsutism, alopecia, and weight gain disrupt quality of life and may lead to noncompliance with the immunosuppressive regimen. New immunosuppressive medications, including mycophenolate mofetil, sirolimus, basiliximab, and daclizumab, have allowed for experimentation with new regimens designed to reduce or allow discontinuation of corticosteroids and calcineurin inhibitors. This review highlights the impact and cost of immunosuppressive side effects and the potential for new immunosuppressive regimens to reduce this substantial clinical burden in transplantation.

Adrenal Cortex Hormones↗
PubMed1999

The modulation of B7.2 and B7.1 on B cells by immunosuppressive agents.

Several recent studies demonstrate that B7.2, but not B7.1, play an important role in allergic inflammation and IgE production. Agents that down-regulate B7.2 may therefore be of benefit for the treatment of Th2-driven allergic diseases. Our current study was carried out to investigate the effect of immunosuppressive agents, cyclosporin A (CsA) and dexamethasone, on B7.2 and B7.1 expression on B cells stimulated with the superantigen, toxic shock syndrome toxin-1 (TSST-1). The analysis of B7.2 and B7.1 on the same cells by flow cytometry demonstrated that TSST-1 up-regulated B7.2+B7.1- but not B7.1+B7.2- on B cells in a dose-dependent fashion. CsA and dexamethasone significantly down-regulated B7.2+B7.1- but up-regulated B7.2-B7.1+ B cells in the presence or absence of TSST-1 (100 ng/ml). Interestingly, the combination of CsA and dexamethasone was much more potent in the inhibition of B7.2 expression than either of these agents alone. As CD40 is known to up-regulate B7.2 expression on B cells, the mechanism of B7.2 down-regulation by CsA and dexamethasone was further studied by investigating the effect of these agents on CD40 expression on B cells. TSST-1 significantly increased CD40 expression on B cells. However, the addition of CsA or dexamethasone significantly down-regulated CD40 expression. Anti-CD40 MoAb significantly reversed the effects of CsA or dexamethasone on B7.2 and B7.1 expression, suggesting that T cell engagement of CD40 plays a role in the mechanisms by which CsA and dexamethasone acts on B cells. These data demonstrate the modulatory effect of CsA and dexamethasone on B7.2 and B7.1 expression on B cells and the potential role of CD40 in mediating this effect.

Adult↗
PubMed1999

Changes in fecal fat excretion from allo-intestine transplanted rats after discontinuance of immunosuppressive agents.

We have previously shown in a rat model of segmental small bowel transplantation, that an ileal graft was more favorable for lipid absorption than a jejunal graft. In the present study, we investigated changes in the lipid absorption of allo-ileal grafts after the withdrawal of an immunosuppressant (methyldeoxyspergualin; given for 1 or 2 weeks at 2.5mg/kg per day) and compared the findings with the results of histological examinations. Heterotopic segmental small bowel transplantation (SBT) was performed using cuff anastomoses in the inbred rat strain combination DA (RT1a) and LEW (RT1). Orthotopic SBT was performed as reconstruction SBT. Reconstruction after resection of the original intestinal tract of the recipient was performed on the seventh day after heterotopic segmental ileal grafting. For the histological evaluation of graft rejection, we performed biopsies in the heterotopic model and autopsies in the orthotopic model. Fecal fat excretion from the orthotopically reconstructed recipients was measured by Folch's method. One- and 2-week use of methyldeoxyspergualin allowed the heterotopic allografts to remain intact histologically for 16.8+/-5.6 and 25.3+/-3.3 (mean+/-SD) days, respectively, whereas the grafts were rejected at 7.3+/-1.1 days when the immunosuppressive drug was not used. All the recipients in the orthotopic group had died by 19 days after reconstruction. After discontinuance of the immunosuppressive agent, fat excretion in feces in the surviving orthotopic grafted rats had increased markedly prior to histologically assessed heterotopic graft rejection. Evaluation of fecal lipid excretion may be a useful parameter for detecting graft rejection in rats.

Animals↗
PubMed1994

Effects of aminosalicylates and immunosuppressive agents on nitric oxide-dependent N-nitrosation reactions.

Recent studies have demonstrated that nitric oxide (NO) rapidly and spontaneously decomposes in oxygenated solutions to generate potent N-nitrosating agents. These electrophilic substances have been shown to mediate mutagenesis and carcinogenesis via the formation of aliphatic and aromatic nitrosamines. We have also demonstrated that extravasated neutrophils and macrophages produce significant amounts of N-nitrosating agents derived exclusively from NO. During the course of these studies, we found that certain antioxidants, including 5-aminosalicylic acid (5-ASA), inhibited the leukocyte-mediated N-nitrosation reaction. Because 5-ASA and other anti-inflammatory and immunosuppressive drugs are used to treat inflammatory bowel disease, we wondered if any of these other compounds might also modulate N-nitrosation reactions in vitro. Therefore, the objectives of this study were to assess the ability of aminosalicylates and certain immunosuppressive agents to inhibit NO-dependent N-nitrosation of a model aromatic amine (2,3-diaminonaphthalene) and to determine whether this inhibitory activity correlated with their oxidation potential. We found that the concentrations necessary to inhibit the N-nitrosation reaction by 50% (IC50) were 25, 50 and 100 microM for 5-ASA, olsalazine (dimeric 5-ASA) and sulfasalazine, respectively. In contrast, sulfapyridine, 4-ASA, N-acetyl-5-ASA, 6-mercaptopurine, azathioprine, and methotrexate were either much less effective or inactive at inhibiting the N-nitrosation reaction. Although 5-ASA was able to fully scavenge the stable free radical 1,1-diphenyl-2-picrylhydrazyl, neither olsalazine nor sulfasalazine was found to be effective at scavenging this weak oxidant. We did find that olsalazine possessed an oxidation potential substantially less than that of sulfasalazine, suggesting that it may, in fact, scavenge more potent oxidizing agents such as the N-nitrosating agent. We conclude that 5-ASA and olsalazine inhibit NO-dependent N-nitrosation reactions by scavenging or decomposing the nitrosating agent(s). We propose that the secondary nitrogen unique to sulfasalazine interacts with the nitrosating agent to yield a secondary nitrosamine, thereby competing for N-nitrosation of our detector.

2-Naphthylamine↗
PubMed1985

Immunosuppressive agents and plasmapheresis in immunological disorders.

Plasmapheresis (PA) was introduced in the treatment of immunologically mediated disease at the beginning of last decade and it was initially claimed to be the panacea for several diseases. It was quickly realized that PA on its own did not have a sustained therapeutic effect and it was the immunosuppressive drugs which could help in the maintenance of an established effect. In this communication we review the immunoregulatory effects of several immunosuppressive agents and discuss their role when used in conjunction with PA primarily in the treatment of rheumatological disorders.

Animals↗
PubMed1994

Comparative influence of steroid hormones and immunosuppressive agents on autoimmune expression in lacrimal glands of a female mouse model of Sjögren's syndrome.

PURPOSE: Previous research has demonstrated that testosterone therapy causes a profound suppression of autoimmune disease in lacrimal glands of female mouse models of Sjögren's syndrome. The aim of the present study was to determine whether other anabolic androgens, nonandrogenic steroids, or immunosuppressive agents might duplicate this hormonal effect. For comparative purposes, we also evaluated the influence of these various pharmacologic compounds on the tear volume, the magnitude of lymphocyte infiltration in the submandibular gland, and the extent of mucosal and peripheral lymphadenopathy. METHODS: Female MRL/MpJ-lpr/lpr mice were administered vehicle, steroids, or immunosuppressive compounds for 21 days after the onset of disease. Lacrimal glands and tears, as well as submandibular glands, spleens, and superior cervical and mesenteric lymph nodes were collected immediately before or after treatment and then processed for analysis. RESULTS: Our results showed that: (1) the immunosuppressive impact of testosterone on lymphocyte infiltration in lacrimal tissue was reproduced by the administration of 19-nortestosterone or cyclophosphamide, but not by therapy with 17 beta-estradiol, danazol, the experimental steroid Org 4094, cyclosporine A or dexamethasone; (2) treatment with testosterone, 19-nortestosterone, cyclophosphamide, or dexamethasone significantly reduced the extent of inflammation in salivary glands; (3) exposure to cyclophosphamide markedly diminished the size of lymphatic and splenic tissues, whereas glucocorticoid treatment only decreased the weight of superior cervical lymph nodes; and (4) administration of 17 beta-estradiol, Org 4094, or dexamethasone led to a significant decrease in tear volume. CONCLUSIONS: Overall, these results demonstrate that androgen or cyclophosphamide therapy may successfully ameliorate autoimmune expression in lacrimal and salivary glands of a female mouse model of Sjögren's syndrome.

Animals↗
PubMed1977

[Modification of immune reactions by antigen-immunosuppressive agent conjugates. V. Studies on antigen-specific activity of 6-mercaptopurine bovine gamma globulin conjugates on the humoral immune response in rabbits].

Rabbits treated daily and for seven consecutive days with 6-mercaptopurine bovine gamma globulin conjugates (MPI--n-BGG; 'I'--characterizes the king of chemical binding and 'n' the number of coupled MP-residues per one mole BGG) show an altered immunological reactivity. A following intradermal immunization with BGG alum adsorbate results in a suppressed anti BGG antibody production on the third day after antigen application (antibody titer 1:320, antibody titer of control animals--pretreated with BGG and uncoupled 6-MP equals 1:5120). Already three days later the antibody titers of the test groups show a significant increase and are two dilution stages higher than the titers of the controls. A suppressive effect on the third day is induced by MPI--13-BGG, MPI--26-BGG, MPI--36-BGG and MPI--46-BGG; the later adjuvant effect can only be seen in the MPI--26-BGG, MPI--36-BGG and MPI--46-BGG but not in the MPI--13-BGG pretreated animal group. While the short time suppression was antigen specific--the humoral immune response against a second unrelated antigen was not reduced--the adjuvans effect was not antigen specific. A pretreatment with the substances mentioned above results in an increased anti BGG and anti HSA serum antibody level. Comparing investigations on the unspecific immunosuppression in rabbits by 6-mercaptopurine shows that application of 10 mg 6-MP/kg/day for seven days at first leads to a suppression but later on to an enhancement of antibody production. Application of 10 mg 6-MP/kg/day for 10 days results in a long lasting suppression without enhancement effect. As a reason for these differences the different catabolism of immunosuppressive agent and antigen is discussed. For the phenomena following antigen specific immunosuppression, similar mechanisms can be responsible.

Agglutination↗
PubMed1991

The effect of a new immunosuppressive agent, FK-506, on xenogeneic neural transplantation in rodents.

This study examines the effect of a novel immunosuppressive agent FK-506 (FK) on the survivability of embryonic (E14) rat ventral mesencephalic tissue after intracerebral grafting to the lateral ventricle of adult mice. The recipient mice were given FK in doses of 10 mg/kg or 1 mg/kg for 2 weeks postgrafting, at which time they were sacrificed and histologically processed except for one group of animals on the high dose (10 mg/kg). In this group most animals died from side effects of the drug during the following days. Only the mice receiving the high dose of FK displayed healthy grafts without signs of rejection.

Animals↗
PubMed2005

Synthetic iminosugar derivatives as new potential immunosuppressive agents.

Several iminosugar derivatives were synthesized, and their effects on the secretion of IL-4 and IFN-gamma from the mouse splenocytes were examined. The effects on membrane expression of other T cell-associated molecules (CD3, CD4, CD8) and B cell-associated molecules (CD19) were also investigated. The experimental data demonstrated that synthetic iminosugars hold potential as immunosuppressive agents.

Animals↗
PubMed2005

Transplant immunosuppressive agents in non-transplant chronic autoimmune hepatitis: the Canadian association for the study of liver (CASL) experience with mycophenolate mofetil and tacrolimus.

BACKGROUND: Conventional treatment of autoimmune hepatitis consists of either prednisone alone or in combination with azathioprine. Ten to 20% of patients do not respond to or are intolerant of this treatment. Novel drug treatments include immunosuppressive drugs such as tacrolimus (TAC), mycophenolate mofetil (MMF), methotrexate and cyclosporine. We describe a multi-centre Canadian experience with MMF and TAC. OBJECTIVE: To study a multi-centre patient population who had failed conventional therapy and were treated with non-conventional medical therapy for autoimmune hepatitis and document response. METHODS: Members of the Canadian Association for the Study of Liver (CASL) obtained MMF from Hoffmann-La Roche Ltd, as part of a compassionate release program, were contacted for standardized data on patients with AIH who received MMF or TAC. Response definitions based on aminotransferase changes were: Complete response (CR)-sustained normalization, partial response (PR)-improvement by greater than 50%, non-response (NR)-less than 50% improvement and relapse (RP)-initial CR or PR followed by an increase in aminotransferases. RESULTS: A total of 16 patients were identified: six in Ontario, one in Quebec, five in Alberta and four in British Columbia. Three were treated with TAC, eleven with MMF and two with combination MMF and TAC. CR was observed in 50%, PR in 12.5%, RP in 25% and NR occurred in 12.5%. The CR for MMF without TAC was approximately 64%. CONCLUSIONS: MMF is effective and well tolerated by patients with autoimmune hepatitis who do not respond to, or are intolerant of, conventional immunosuppressive agents.

Adult↗
PubMedDate not supplied

[Biomarkers and pharmacokinetic-pharmacodynamic studies of immunosuppressive agents].

Biomarkers are characteristics that are objectively measured and evaluated as indicators of normal biological processes, pathogenic processes, or pharmacological responses to a therapeutic intervention. Biomarkers of pharmacological responses allow pharmacokinetic-pharmacodynamic modelling based on what is known of the mechanism of action of the drug. Characteristics predictive of the pharmacological response, such as a genotype, constitute a specific category of biomarkers and can be used as covariates in the model. In the case of "classical" immunosuppressive agents, the biomarkers of response most studied are lymphocyte calcineurin activity for ciclosporin and tacrolimus, and inosine monophosphate dehydrogenase activity for mycophenolate. Pharmacokinetic-pharmacodynamic analysis of monoclonal antibodies with immunosuppressive properties requires complex models and immunological biomarkers such as, for example, the number of circulating lymphocytes with a given surface antigen. Pharmacodynamic indirect response models are particularly relevant in this instance.

Antibodies, Monoclonal↗
PubMed1991

The effects of immunosuppressive agents on in vitro production of human immunoglobulins.

We have evaluated the effects of CsA, methylprednisolone (MP), 6-mercaptopurine (6-MP), and FK506 on T cell-dependent and T cell-independent immunoglobulin production. FK506 and 6-MP were potent inhibitors of IgG and IgM production by PWM-stimulated peripheral blood mononuclear cells, which depend on the presence of T cells. CsA was less effective in this system and MP actually enhanced IgG and IgM production. In order to assess the direct effects of these various immunosuppressive agents on B cells, we utilized human B cell lines representing different stages of B cell differentiation. The B cell lines CESS and SKW6.4 exhibit increased production of IgG and IgM, respectively, in response to interleukin-6. These cells represent activated, but not fully differentiated, B cells. CsA inhibited IL-6-induced IgG production by CESS cells by 64% at 100 ng/ml and 6-MP inhibited this response by 82% at 250 ng/ml. Neither CsA nor 6-MP effectively inhibited IL-6-induced IgM production by SKW6.4 cells. MP at 250 ng/ml inhibited IL-6-induced IgG production by 89%, but enhanced IL-6-induced IgM production more than two-fold. FK506 did not inhibit IL-6-induced IgG or IgM production, suggesting that it has no direct effect on the ability of B cells to respond to this differentiation factor. These experiments clearly demonstrate that CsA, MP and 6-MP have direct inhibitory effects on the response of human B cells to IL-6. In contrast, FK506 has no direct effect on these B cells lines, but is more potent than the other agents at inhibiting T cell-dependent immunoglobulin production.

Anti-Bacterial Agents↗
PubMed1983

Alterations in rat pulmonary macrophage function by the immunosuppressive agents cyclosporine, azathioprine, and prednisolone.

Disturbances of the immune response of the lung induced by the action of immunosuppressive agents on the functional abilities of rat pulmonary alveolar macrophages (PAM) were analyzed following in vitro incubation or in vivo administration (for 30 days) of cyclosporinea, (CsA) azathioprine (Az) or prednisolone (Pr). Two major parameters were analyzed: oxygen consumption and superoxide release as indices of the overall state of oxygen metabolism of these cells reflecting the integrity of PAM oxidative mechanisms of microbicidal activity, and chemotaxis, an event clinically important for normal defense to infection. In vitro incubation with cyclosporine at concentrations as low as 10(-9) M caused a 52% inhibition of PAM superoxide release, but Az had no effect at concentrations up to 10(-6) M. Prednisolone caused a 38% inhibition of superoxide release; comparable levels of inhibition with Pr required concentrations at least 10-fold greater than with cyclosporine. Further experiments indicated that cyclosporine induced a 40% inhibition after contact with PAM for only 30 min. In vivo experiments indicated that cyclosporine (5 mg/kg), Az (20 mg/kg), or Pr (2 or 0.5 mg/kg) administered intraperitoneally had no effect on the number of PAM available for host defense, PAM oxygen consumption, or PAM superoxide release. However, PAM from cyclosporine-treated animals demonstrated complete inhibition of active migration or chemotaxis in modified Boyden chambers upon incubation with formylmethionyl-leucyl-phenylalanine (FMLP). The effect was apparently dampened by simultaneous administration of Pr with cyclosporine. These experiments suggest that with the exception of a marked effect on chemotaxis the in vivo effects of physiologic amounts of cyclosporine on PAM function are modest compared with the marked depression after in vitro addition.

Animals↗
PubMedDate not supplied

[Side effects and toxicity of immunosuppressive agents].

The toxicity and side effects of immunosuppressive drugs currently used in the clinical practice of renal transplantation are examined. Different immunosuppressive drugs act during different points of T-cell maturation, thus allowing the concomitant association of different drugs to reduce clinical toxicity. Immunosuppressive drugs have two kinds of toxicity: "therapeutic toxicity" and "nontherapeutic toxicity". Only the latter is the topic of this review. A similar toxicity profile is shared by various immunosuppressive drugs. In planning treatments, drugs must be chosen based on their toxicity profile and their adequate effect on the clinical syndrome being treated. The main calcineurine inhibitors (CNI) side effects are nephrotoxicity, cardiotoxicity, and post transplant diabetes mellitus (PTDM). Steroids have multiple side effects, the most important of which are negative effects on bone and cardiovascular function. New drug trials have been undertaken to find immunosuppressive drugs with lower toxicity and less negative impact on bone and cardiovascular function. In preliminary studies, Sirolimus seems to have a less severe side effects profile.

Antibodies↗