Tacrolimus (FK506) reduces ischemia-induced hippocampal damage in rats: a 7- and 30-day study

The neuroprotective effect of the immunosuppressant agent FK506 was evaluated in rats after brain ischemia induced for 15 min in the 4-vessel occlusion model. In the first experimental series, single doses of 1.0, 3.0 or 6.0 mg FK506/kg were given intravenously (iv) immediately after ischemia. In the second series, FK506 (1.0 mg/kg) was given iv at the beginning of reperfusion, followed by doses applied intraperitoneally (ip) 6, 24, 48, and 72 h post-ischemia. The same protocol was used in the third series except that all 5 doses were given iv. Damage to the hippocampal field CA1 was assessed 7 or 30 days post-ischemia on three different stereotaxic planes along the septotemporal axis of the hippocampus. Ischemia caused marked neurodegeneration on all planes (P<0.001). FK506 failed to provide neuroprotection to CA1 both when applied iv as a single dose of 1.0, 3.0 or 6.0 mg/kg (experiment 1), and after five iv injections of 1.0 mg/kg (experiment 3). In contrast, the repeated administration of FK506 combining iv plus ip administration reduced CA1 cell death on all stereotaxic planes both 7 and 30 days post-ischemia (experiment 2; P<=0.01). Compared to vehicle alone, FK506 reduced rectal temperature in a dose-dependent manner (P<=0.05); however, this effect did not alter normothermia (37ºC). FK506 reduced ischemic brain damage, an effect sustained over time and apparently dependent on repeated doses and on delivery route. The present data extend previous findings on the rat 4-vessel occlusion model, further supporting the possible use of FK506 in the treatment of ischemic brain damage.

Exposição de fibroblastos provenientes de pterígios recidivados e da cápsula de Tenon normal ao tacrolimus (FK-506)

OBJETIVO: Avaliar a taxa de proliferação de fibroblastos provenientes de pterígios recidivados e da cápsula de Tenon normal, quando expostos in vitro ao tacrolimus (FK 506). MÉTODOS: Foi realizado estudo prospectivo, controlado, avaliando-se 8 amostras de explantes de cápsula de Tenon de pterígios recidivados e 6 de cápsula de Tenon normal, obtidas na Faculdade de Medicina de Botucatu - UNESP. A cápsula de Tenon normal foi colhida da região temporal inferior, do mesmo portador de pterígio. As amostras foram cultivadas em meio específico e posteriormente expostas ao tacrolimus 1M (FK 506), em única exposição, com avaliação da taxa de proliferação celular 1, 5, 12 e 19 dias após a exposição. RESULTADOS: Avaliando-se a proliferação dos fibroblastos provenientes de cápsula de Tenon de pterígios recidivados e da cápsula de Tenon normal, os fibroblastos expostos ao tacrolimus tiveram taxa de proliferação significativamente menor (p<0,05) do que quando não houve exposição a droga, quando a avaliação foi feita 1 dia após a exposição. Quando a avaliação foi feita 19 dias após a exposição, a taxa de proliferação foi maior nos grupos expostos a droga. CONCLUSÃO: Os fibroblastos provenientes da cápsula de Tenon de pterígios recidivados apresentaram taxa de proliferação significativamente menor um dia após a exposição ao tacrolimus. Novos estudos devem ser realizados para definir dose e tempo de exposição dos fibroblastos a droga, com o intuito de definir se o tacrolimus pode ser útil como tratamento coadjuvante do pterígio.

Protective effects of Tacrolimus, a calcineurin inhibitor, in experimental periodontitis in rats

Objective: Periodontitis is a well-appreciated example of leukocyte-mediated bone loss and inflammation with pathogenic features similar to those observed in other inflammatory diseases, such as arthritis. Since Tacrolimus, is an immunomodulatory drug used for the treatment of some cases of arthritis, we hypothesized that it may modulate periodontal disease.Design: Using a murine model of ligature-induced periodontal disease, we assessed the effects of daily administrations of Tacrolimus (1 mg/kg body weight) on bone loss, enzymatic (myeloperoxidase) analysis, differential white blood cells counts, airpouch exudate and cytokine expression for 5-30 days.Results: Radiographic, enzymatic (myeloperoxidase) and histological analysis revealed that Tacrolimus reduced the severity of periodontitis. More specifically, Tacrolimus suppressed the expression of serum interleukin (IL-1 beta), tumour necrosis factor (TNF-alpha), IL-6, airpouch exudate PGE(2) and leukocytosis usually observed after the induction of periodontitis. Tacrolimus treatment in periodontitis-induced rats conferred protection against the inflammation-induced tissue and bone loss associated with periodontitis, through a mechanism involving IL-1 beta, TNF-alpha and IL-6.Conclusions: the effects of Tacrolimus on periodontal disease pathogenesis may provide clues to a novel approach to host modulation therapy in destructive periodontal disease. (C) 2007 Elsevier Ltd. All rights reserved.

Immunosuppressant Prograf (R) (Tacrolimus) Induces Histopathological Disorders in the Peritubular Tissue of Rat Testes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Structural alterations in the seminiferous tubules of rats treated with immunosuppressor tacrolimus

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Interaction of the Anti-Inflammatory Annexin A1 Protein and Tacrolimus Immunosuppressant in the Renal Function of Rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Oral health in renal transplant recipients administered cyclosporin A or tacrolimus

OBJECTIVE: the aim of this study was to determine the oral status of renal transplant recipients receiving cyclosporin A (CsA) or tacrolimus (FK-506) as immunosuppressant.SUBJECTS AND METHODS: A total of 88 renal transplant recipients receiving CsA (63 men and 25 women, mean age 51.4 years) and 67 receiving FK-506 (57 men and 10 women, mean age 33.5 years) were included in the study. Donor type, histocompatibility, cold ischemia time and prior delayed graft function were similar between the two groups. Demographics and pharmacological data were recorded for all subjects.RESULTS: the results demonstrated that CsA caused a greater number of oral diseases. A greater number of gingival overgrowth was present in patients treated with CsA. However, the combined use with calcium channel blockers increased the gingival overgrowth number. The occurrence of candida in saliva was observed in 80 renal recipients treated with CsA and 20 treated with FK-506. The presence of squamous oral carcinoma (n = 3) and herpes simplex (n = 10) was observed in patients treated with CsA. These alterations were not observed in renal recipients treated with FK-506.CONCLUSIONS: Renal recipients constitute a high-risk group for oral diseases, as they are immunocompromised. However, the FK-506 regime appears to ameliorate this effect, compared with CsA. Adequate pre- and post-transplant oral health care is recommended for these subjects, irrespective of the time interval for which the drug is administered.

Conversion of immunosuppressive monotherapy from cyclosporin A to tacrolimus reverses bone loss in rats

Tacrolimus is used for transplant patients with refractory graft rejection and those with intolerance to cyclosporin (CsA), without the disfiguring adverse effects frequently attributed to CsA therapy. Since we have shown that CsA-associated bone loss can also affect alveolar bone, the purpose of this study was to evaluate the effects of conversion of monotherapy from CsA to tacrolimus on alveolar bone loss in rats. Groups of rats were treated with either CsA (10 mg/kg/day, s.c.), tacrolimus (I mg/kg/day, s.c.), or drug vehicle for 60 and 120 days, and an additional group received CsA for 60 days followed by conversion to tacrolimus for a further 60-day period. Bone-specific alkaline phosphatase (BALP), tartrate-resistent acid phosphatase (TRAP-5b), calcium (Ca2+), interleukin (IL)-1 beta, IL-6, and tumor necrosis factor alpha (TNF-alpha) concentrations were evaluated in the serum. Analyses of bone volume, bone surface, number of osteblasts, and osteoclasts were performed. Treatment with CsA for either 60 or 120 days was associated with bone resorption, represented by lower bone volume and increased number of osteoclasts; serum BALP, TRAP-5b, IL-1 beta, IL-6, and TNF-alpha were also higher in these animals. After conversion from CsA to tacrolimus, all the altered serum markers returned to control values in addition to a significant increase of bone volume and a lower number of osteoclasts. This study shows that conversion from CsA to tacrolimus therapy leads to a reversal of the CsA-induced bone loss, which can probably be mediated by downregulation of IL-1 beta, IL-6, and TNF-alpha production.

Cyclosporin but not tacrolimus significantly increases salivary cytokine contents in rats

Background: Cyclosporin (CsA) and tacrolimus (FK-506) are immunosuppressive drugs that specifically inhibit T-cell activation via calcineurin inhibition. Gingival overgrowth is a common side effect following the administration of CsA. The severity of gingival overgrowth seen in patients taking FK-506 is less than that observed with CsA. Little is known about the involvement of saliva in drug-induced gingival overgrowth. The purpose of this study was to investigate the salivary contents of tumor growth factor β1 (TGF-β1), epidermal growth factor (EGF), and interleukin-6 (IL-6) as well as the hystometry of gingival tissue obtained from rats treated with either FK-506 or CsA. Methods: For 30 or 60 days rats received daily subcutaneous injection doses of either CsA or FK-506 (10 mg/kg). The concentrations of TGF-β1, EGF, and IL-6 in saliva were determined by enzyme-linked immunosorbent assay, and after histological processing, the oral epithelium and connective tissue were assessed at the region of the lower first molars. Results: The levels of TGF-β1, EGF, and IL-6 in saliva were not significantly altered by any of the treatments after 30 days. After 60 days of treatment with CsA, gingival overgrowth and significant increase in salivary TGF-β1, EGF, and IL-6 concentrations were observed; no statistically significant changes were induced by FK-506. Conclusion: Within the limits of this experimental study, it can be concluded that CsA, but not FK-506, induced gingival overgrowth associated with an increase of the salivary levels of the cytokines TGF-β1, EGF, and IL-6.

Biochemical evaluation of glycemic levels of long-term tacrolimus therapy in rats

One of the more serious complications following transplantation is the development of post-transplantation diabetes mellitus (PTDM), which has a major impact on the quality of life, with effects ranging from the control of glycemia times to increased susceptibility to infections and cardiovascular complications. It has been suggested that immunosuppressive therapy, mainly tacrolimus therapy, may be an important factor in the development of PTDM. There is a lack of studies that explore the effects of long-term tacrolimus on PTDM in animal protocols. The objective of this study was therefore to evaluate the effects of long-term therapy with tacrolimus in rats. One group was treated with tacrolimus, injected subcutaneously, in a daily dose of 1 mg/kg of body weight. The chosen dose was sufficient to achieve therapeutic tacrolimus serum levels. The experimental periods were 60, 120, 180 and 240 days. One group was used as control and received daily subcutaneous injections of saline solution during all periods. A tendency towards increased glycemia levels during the initial periods (60 and 120 days) was observed. However, at 180 and 240 days, the glycemia levels were not statistically different from that of the control group of the same period. It may thus be concluded that the deleterious effects of tacrolimus therapy on glycemia may be a time-related side effect.

The effects of up to 240 days of tacrolimus therapy on the gingival tissues of rats - A morphological evaluation

Background: Tacrolimus, an immunosuppressive drug used in organ transplantation, has been reported not to induce gingival overgrowth. However, prevalence studies are limited, and the methods used for assessing gingival overgrowth varies among studies. Objective: The purpose of this study was to evaluate the effects of up to 240 days of tacrolimus therapy on gingival tissues of rats. Materials and methods: Rats were treated for 60, 120, 180 and 240 days with daily subcutaneous injections of 1 mg/kg body weight of tacrolimus. After histological processing, the oral and connective tissue, volume densities of fibroblasts (Vf), collagen fibers (Vcf) and other structures (Vo) were assessed in the region of the lower first molar. Results: After 60 and 120 days of treatment with tacrolimus, gingival overgrowth was not observed. The gingival epithelium, connective tissue, as well as the values for Vf, Vcf, and Vo were similar to those of the control rats (P > 0.05). After 180 and 240 days of the treatment, gingival overgrowth was associated with a significant increase in the gingival epithelium and connective tissue as well as an increase in the V f and Vcf (P < 0.05). Conclusions: Within the limits of the experimental study, it may be concluded that the deleterious side effects of tacrolimus on the gingival tissues of rats may be time-related. © 2007 Blackwell Munksgaard All rights reserved.

Avaliação do efeito da Sinvastatina em ratos submetidos a periodontite experimental e imunossuprimidos por Ciclosporina-A e Tacrolimus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Treatment with tacrolimus enhances alveolar bone formation and decreases osteoclast number in the maxillae: A histomorphometric and ultrastructural study in rats

Recent studies have suggested that tacrolimus monotherapy is a beneficial therapeutic alternative for the normalization of cyclosporin- induced bone loss in animal models and humans. The mechanism accounting for this action is unclear at present. In the present study, we attempted to determine the effect of tacrolimus monotherapy on alveolar bone using histological, histomorphometrical and transmission electron microscopy (TEM).Groups of rats (n= 10 each) were treated with either tacrolimus (1mg/ kg/ day, s.c.) or drug vehicle for 60 days. Fragments containing maxillary molars were processed for light microscopy to investigate the alveolar bone volume, trabecular separation, number of osteoclasts and osteoblasts, and transmission electron microscopy to investigate their ultrastructural basic phenotype.Treatment with tacrolimus monotherapy during 60 days may induce increases in alveolar bone volume (BV/ TV,%; P < 0.05) and a non- significant decrease in trabecular separation (Tb. Sp, mm; P > 0.05), represented by a decrease in osteoclast number (N. Oc/ BS; P < 0.05) and maintenance of osteoblast number (N. Ob/ BS; P > 0.05). Osteoblasts were often observed as a continuous layer of active cells on the bone surface. Osteoclasts appeared to be detached from the resorbed bone surface, which was often filled by active osteoblasts and collagen- rich matrix. Moreover, osteoclasts in the treated group were frequently observed as inactive cells (without ruffled border, clear zone and detached from the bone surface).Within the limits of the present study, we conclude that tacrolimus leads to an increase in alveolar bone formation, which probably exerts action on osteoclasts. Tacrolimus could, therefore, play a crucial role in the control of both early osteoclast differentiations from precursors, as well as in functional activation.

Uso subconjuntival de lipossomas com rapamicina e tacrolimus tópico no tratamento de ceratoconjuntivite seca em cães

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cytotoxic and genotoxic effects of high concentrations of the immunosuppressive drugs cyclosporine and tacrolimus in MRC-5 cells

Immunosuppressive drugs are used to suppress immune system activity in transplant patients and reduce the risk of organ rejection. The present study evaluated the potential cytotoxic, genotoxic and mutagenic of the immunosuppressive drugs cyclosporine (CsA) and tacrolimus (FK-506) on normal human fibroblasts (MRC-5 cells). Based on plasma concentrations of the immunosuppressive drugs, which were obtained from the records of kidney transplant patients at the Kidney Institute of Londrina, Brazil, 11 concentrations of each immunosuppressive were chosen to evaluate cell viability using the MIT assay. From these results, CsA and FK-506 concentrations of 135, 300, 675, and 1520 ng/ml and 8, 16, 24, and 32 ng/ml, respectively, were evaluated using (i) the comet assay, (ii) the nuclear division index (NDI), (iii) the micronucleus test (CBMN) and (iv) cell proliferation curves generated by quantifying cell numbers and protein levels. In this study, 1520 to 3420 ng/ml CsA decreased cell viability after 48 h of exposure. Genotoxic effects were observed only with a concentration of 1520 ng/ml after 3 h of exposure and with concentrations of 675 and 1520 ng/ml after 24 h of exposure. Mutagenic effects were observed only for the concentration of 1520 ng/ml. FK-506 decreased cell viability after 72 h of exposure for concentrations up to 20 ng/ml; genotoxic effects were observed with concentrations up to 8 ng/ml for both treatment times (3 and 24 h) and mutagenic effects were observed with concentrations of 24 and 32 ng/ml after 24 h of treatment. The cell proliferation curves demonstrated the absence of cytostatic effects of these drugs, and these data were confirmed by the NDI analysis. Our results suggest that concentrations lower than 300 ng/ml of CsA and 16 ng/ml of FK-506 are safe for use, as they did not induce genotoxic and mutagenic damage or affect MRC-5 cell viability and proliferation. (C) 2014 Elsevier GmbH. All rights reserved.