Does the association of tacrolimus and mycophenolate mofetil change the healing of the abdominal wall? study in rats submitted to ischemia and kidney reperfusion / A associação de tacrolimus e micofenolato mofetil altera a cicatrização da parede abdominal? estudo em ratos submetidos à isquemia e reperfusão renal

ABSTRACT Background: Tacrolimus and mycophenolate mofetil are immunosuppressive agents widely used on the postoperative period of the transplants. Aim: To evaluate the influence of the association of them on the abdominal wall healing in rats. Methods: Thirty-six Wistar rats were randomly assigned in three groups of 12. On the early postoperative period, four of the control group and three of the experimental groups died. The three groups were nominated as follow: control group (GC, n=8); group I (GI, n=11, standard operation, mycophenolate mofetil and tacrolimus); group II (GII, n=10, standard operation, mycophenolate mofetil and tacrolimus). The standard operation consisted of right total nephrectomy and 20 min ischemia of the left kidney followed by reperfusion. Both NaCl 0.9% and the immunosuppressive agents were administered starting on the first postoperative day and continuing daily until the day of death on the 14th day. On the day of their deaths, two strips of the anterior abdominal wall were collected and submitted to breaking strength measurement and histological examination. Results: There were no significant differences in wound infection rates (p=0,175), in the breaking strength measurement and in the histological examination among the three groups. Conclusion: The combination of the immunosuppressive agents used in the study associated with renal ischemia and reperfusion does not interfere in the abdominal wall healing of rats.

RESUMO Racional: O tacrolimus e o micofenolato mofetil são imunossupressores amplamente utilizados no pós-operatório dos transplantes de órgãos. Objetivo: Avaliar os efeitos deles sobre a cicatrização da parede abdominal em ratos. Métodos: Foram utilizados 36 ratos Wistar, distribuídos aleatoriamente em três grupos de 12. No pós-operatório imediato, quatro do grupo controle e três do grupo experimentação morreram. Os três grupos receberam as seguintes denominações: grupo controle (GC, n=8); grupo I (GI, n=11, operação-padrão, micofenolato mofetil e tacrolimus); grupo II (GII, n=10, operação-padrão, micofenolato mofetil e tacrolimus). A operação-padrão consistiu de nefrectomia total à direita, isquemia durante 20 min seguida de reperfusão do rim esquerdo. Solução de NaCl 0,9% e micofenolato mofetil + tracolimus foram administradas a partir do 1° dia do pós-operatório e mantidas até o dia do sacrifício dos animais, no 14° dia. Na data do sacrifício, foram retirados dois fragmentos da parede abdominal para análise da resistência à ruptura e exame histológico. Resultados: Não houve diferença estatisticamente significativa no índice de infecção de ferida operatória (p=0,175), nos valores de resistência de ruptura e nos achados histopatológicos entre os três grupos de animais. Conclusão: Os esquemas de imunossupressão empregados associados ao fenômeno da isquemia-reperfusão renal não induzem fraqueza significativa da cicatriz da parede abdominal em ratos no 14° dia de pós-operatório.

Effects of mycophenolate sodium on mucociliary clearance using a bronchial section and anastomosis rodent model

OBJECTIVE: To study the effects of mycophenolate sodium on mucociliary clearance. INTRODUCTION: Mycophenolate is one of the most commonly used immunosuppressive drugs in lung transplantation. Although its pharmacokinetic properties are well defined, its side effects on mucociliary clearance have not yet been studied. METHODS: Sixty rats were subjected to left bronchial section and anastomosis. The right bronchus was used as a control. After surgery, the rats were assigned to two groups based on whether they received saline solution (n = 30) or mycophenolate sodium (n = 30). After 7, 15, or 30 days of treatment, 10 animals from each group were sacrificed, and in vitro mucus transportability, in situ mucociliary transport velocity and ciliary beat frequency were measured. RESULTS: The analysis of mucus transportability revealed that neither mycophenolate nor bronchial section altered any transportability related property for up to 30 days of treatment after surgery (p>0.05). With regard to ciliary beat frequency, the operated left bronchi from the mycophenolate group showed a significant decrease on post-surgical day 30 (p = 0.003). In addition, we found a significant reduction in the in situ mucociliary transport velocity in the mycophenolate-treated group (p = 0.0001). DISCUSSION: These data add important information regarding mucociliary clearance dysfunction following mycophenolate therapy and suggest that mycophenolate might contribute to the high incidence of respiratory tract infections in lung transplant patients. Further studies are needed to investigate the combined action of mycophenolate with other immunosuppressive drugs and to establish methods to protect and recover mucociliary clearance, an important airway defense mechanism.

Is mycophenolate more than just an immunosuppressant?--An overview.

The development of immunosuppressant compounds, such as cyclosporine and tacrolimus was crucial to the success of transplant surgery and for treatment of autoimmune diseases. However, immunosuppressant therapy may increase the concentrations of reactive oxygen species (ROS), inducing oxidative damage such as an increased vascular damage. The major source of ROS in the vascular endothelial cells is NADPH oxidase. The subunit structure and function of this enzyme complex in vascular cells differs from that in phagocytic leucocytes. The enzyme subunits Nox1, Nox2 and Nox4 are only found in vascular cells. The GTP-dependent protein subunit Rac 1 needs to be activated for this enzyme to function. Inhibiting this protein subunit should reduce NADPH oxidase-induced oxidative stress. In the cardiovascular system, oxidative stress is observed as hypertension, hypertrophy, fibrosis, conduction abnormalities and endothelial dysfunction, as well as cardiac allograft vasculopathy in transplant patients. In contrast to cyclosporine and tacrolimus, the immunosuppressant mycophenolate inhibits the Rac 1 subunit thus inhibiting NADPH oxidase in the vasculature. This may reduce oxidative stress, prevent the development of cardiac allograft vasculopathy, decrease the deterioration of vascular function and improve cardiovascular function chronically in transplant patients. This overview discusses whether this antioxidant immunosuppressive property could translate into a more general protective role for mycophenolate in the prevention of cardiovascular disease.

Inmunosupresión para receptores de trasplante renal: estrategias actuales / Immunosuppression for kidney transplant recipients: current strategies

Immunosuppressive therapy aims to protect transplanted organs from host responses. The success achieved during the last two decades in patient and graft survival is mainly related to the development and clinical use of efficacious immunosuppressive drugs. Nevertheless, the challenge of achieving a balance of adequate graft protection while minimizing the adverse consequences of excessive immunosuppression in the long-term continues. Current maintenance immunosuppression for renal transplant recipients generally consists of a calcineurin inhibitor plus an adjunctive antiproliferative agent, and steroids. The addition of induction therapy with a variety of monoclonal or polyclonal antibodies provides a more potent immunosuppression and its use is more relevant in patients with a high immunological risk. More recently, mammalian target of rapamycin inhibitors have been incorporated in different schemes proven its efficacy in a number of protocols. The incidence of acute rejection is now in its lower historical percentage and excellent results are reported from many transplant centers all over the world due mainly to a judicious combination of these drugs evaluated through many clinical studies. However, long-term use of immunosuppressive drugs convey inherent risks which translate in an increase of cancers and infections, among others. Ongoing investigations and clinical protocols involving new immunosuppressive drugs and biological agents are yielding important information on how to obtain tolerance or the nearest to this goal. Furthermore, there should be a continuous improvement in patient and graft survival, as the use of different immunosuppressive agents for induction and maintenance are individualized (adapted to each patient).

La terapia inmunosupresora empleada en receptores de trasplante tiene el objetivo de proteger el injerto de la respuesta inmunoloógica generada por parte del huésped. El éxito logrado en el transcurso de las últimas dos décadas en la supervivencia de receptores e injertos, ha dependido en gran medida del desarrollo y uso clínico de fármacos inmunosupresores de probada eficacia. Empero el enorme beneficio que han representado, el reto continúa para mantener un balance adecuado entre la protección inmunológica del injerto y la minimización de las consecuencias adversas derivadas de su indispensable utilización a largo plazo. La terapia inmunosupresora actual de mantenimiento en receptores de trasplante renal consiste habitualmente en la administración de un inhibidor de calcineurina, un agente antiproliferativo, como adyuvante, y esteroides. La adición de terapia de inducción, con modalidades biológicas de anticuerpos mono o policlonales, proveen un mayor grado de inmunosupresión y su empleo adquiere gran relevancia en pacientes con mayor riesgo inmunológico. En una etapa más reciente, los inhibidores del blanco de rapamicina han sido introducidos en varios esquemas después de probar su eficacia en múltiples protocolos. La incidencia de rechazo agudo ha alcanzado sus más bajos índices históricos y los resultados alcanzados en muchos centros de trasplante del mundo son excelentes, derivados en gran medida de la combinación juiciosa de estos fármacos, evaluados en una gran variedad de estudios. El empleo crónico de estos fármacos conlleva riesgos inherentes que se traducen en riesgos incrementados para el desarrollo de infecciones y neoplasias, entre otros. Así, mientras esperamos nuevos avances derivados de una gran profusión de estudios de investigación y protocolos clínicos con nuevas drogas inmunosupresoras y compuestos biológicos, encaminados a obtener tolerancia o lo más cercano a este propósito, deberemos ser capaces de continuar mejorando la vida funcional de la mayoría de los injertos y, desde luego, de sus receptores, "individualizando" (de acuerdo con los riesgos de cada paciente) el empleo de los agentes inmunosupresores disponibles para inducción y mantenimiento.

Introducción de micofenolato asociado a suspensión o reducción de la ciclosporina en trasplante renal: evaluación de una estrategia para el manejo de la nefropatía crónica del injerto / Effects of the administration of micofenolate mofetil associated to suspension or reduction of the cyclosporin in kidney transplant: evaluation of a management strategy of the chronic graft nephropathy

Esta revisión incluyó seis pacientes trasplantados, en tratamiento con CyA (Neoral) y Prednisona, con diagnóstico clínico de NCI caracterizado por un alza progresiva de la creatinina plasmática, y en cuatro de ellos estudio histológico concordante. MM se incorporó en un lapso no inferior a seis semanas, período en el cual se redujo y/o suspendió la CyA. La función renal y las complicaciones del tratamiento se evaluaron semanalmente en este período y en forma mensual hasta los 24 meses. La introducción de MM se efectuó en promedio a los 66 meses post-trasplante (rango 12 a 240 meses). Durante los 24 meses de seguimiento, se observó una tendencia progresiva a disminuir los niveles de creatinina. Sin embargo, esta diferencia no fue estadísticamente significativa. Durante este período no se observó ningún episodio de rechazo agudo o eventos adversos mayores. Sólo un paciente presentó toxicidad gastrointestinal, secundaria al uso de MM. La adición de MM acompañado de reducción o suspensión de CyA, en este grupo de pacientes con NCI, permitió mantener estables los niveles de creatinina durante el período en estudio, disminuyendo aparentemente la progresión de la enfermedad. La conversión demostró ser segura.

Effects of mycophenolate mofetil on renal interstitial fibrosis after Unilateral ureteral obstruction in rats / 华中科技大学学报（医学）（英德文版）

To investigate the effects of mycophenolate mofetil (MMF) on the process of renal interstitial fibrosis, unilateral ureteral obstruction (UUO) model was established in rats. Twenty Sprague-Dawley rats underwent UUO and received vehicle (n = 10) or MMF (20 mg.kg-1.d-1, by daily gastric gavage, n = 10) during a period of 5 days following surgery, and the additional 10 rats were served as sham-operated group. The rats were killed 5 days after surgery. Immunohistochemistry was performed on renal tissue for proliferating cell nuclear antigen (PCNA), alpha-smooth muscle actin (alpha-SMA) and type I and III collagen (col I, col III). Histological studies were also done by MASSON staining. Five days after surgery, proliferating cells in tubules, interstitium as well as interstitial myofibroblast (MyoF) infiltration and interstitial col I, col III deposition were all significantly reduced by MMF treatment. MMF also alleviated the histological changes of UUO rats. These results suggested that the reduction of interstitial MyoF infiltration may be an important event by which MMF prevents renal injury caused by UUO and MMF could be used to limit the progression of renal fibrosis.