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Tacrolimus (TAC) is an immunosuppressant drug that prevents organ rejection after transplantation. This drug is transported from cells via P-glycoprotein (ABCB1) and is a metabolic substrate for cytochrome P450 (CYP) 3A enzymes, particularly CYP3A4 and CYP3A5. Several single-nucleotide polymorphisms (SNPs) have been identified in the genes encoding CYP3A4, CYP3A5, and ABCB1, including CYP3A4-392A/G (rs2740574), CYP3A5 6986A/G (rs776746), and ABCB1 3435C/T (rs1045642). This study aims to evaluate the association among CYP3A4-392A/G, CYP3A5-6986A/G, and ABCB1-3435C/T polymorphisms and TAC, serum concentration, and biochemical parameters that may affect TAC pharmacokinetics in Mexican kidney transplant (KT) patients. METHODS: Forty-six kidney transplant recipients (KTR) receiving immunosuppressive treatment with TAC in different combinations were included. CYP3A4, CYP3A5, and ABCB1 gene polymorphisms were genotyped using qPCR TaqMan. Serum TAC concentration (as measured) and intervening variables were assessed. Logistic regression analyses were performed at baseline and after one month to assess the extent of the association between the polymorphisms, intervening variables, and TAC concentration. RESULTS: The GG genotype of CYP3A5-6986 A/G polymorphism is associated with TAC pharmacokinetic variability OR 4.35 (95%CI: 1.13-21.9; p = 0.0458) at one month of evolution; in multivariate logistic regression, CYP3A5-6986GG genotype OR 9.32 (95%CI: 1.54-93.08; p = 0.028) and the use of medications or drugs that increase serum TAC concentration OR 9.52 (95%CI: 1.79-88.23; p = 0.018) were strongly associated with TAC pharmacokinetic variability. CONCLUSION: The findings of this study of the Mexican population showed that CYP3A5-6986 A/G GG genotype is associated with a four-fold increase in the likelihood of encountering a TAC concentration of more than 15 ng/dL. The co-occurrence of the CYP3A5-6986GG genotype and the use of drugs that increase TAC concentration correlates with a nine-fold increased risk of experiencing a TAC at a level above 15 ng/mL. Therefore, these patients have an increased susceptibility to TAC-associated toxicity.
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Subfamília B de Transportador de Cassetes de Ligação de ATP , Citocromo P-450 CYP3A , Imunossupressores , Transplante de Rim , Polimorfismo de Nucleotídeo Único , Tacrolimo , Humanos , Citocromo P-450 CYP3A/genética , Transplante de Rim/efeitos adversos , Tacrolimo/sangue , Tacrolimo/farmacocinética , Tacrolimo/administração & dosagem , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Feminino , Masculino , Polimorfismo de Nucleotídeo Único/genética , Adulto , México , Imunossupressores/farmacocinética , Imunossupressores/sangue , Imunossupressores/administração & dosagem , Pessoa de Meia-Idade , Genótipo , Rejeição de Enxerto/genéticaRESUMO
SUMMARY: Although tacrolimus (TAC) significantly reduces allograft rejection incidence in solid-organ transplantation, its long-term use is associated with an increased risk of TAC-induced nephrotoxicity. In this study, we investigated the renoprotective effects of green tea extract (GTE) with or without the dipeptidyl peptidase 4 inhibitor, gemigliptin, by assessing serum creatinine levels, the amount of proteinuria, and histopathology in TAC-induced nephrotoxicity. TAC-induced nephrotoxicity was induced by intraperitoneal TAC injection, GTE was administered via subcutaneous injection, and gemigliptin was administered orally. Mice with TAC-induced nephrotoxicity exhibited a significant increase in both serum creatinine levels and 24-hour urine protein. However, when treated with GTE via subcutaneous injection, mice showed a decrease in serum creatinine levels and the amount of proteinuria. When GTE was combined with gemigliptin, further renoprotective effects were observed in biochemical assessments, consistent with the attenuation of TAC-induced nephrotoxicity in histopathology. The expression of p53 protein was lower in the mice treated with the combination of GTE and gemigliptin compared to mice with TAC-induced nephrotoxicity. Our results demonstrate that the combination of GTE and gemigliptin treatment reveals synergistic renoprotective effects by decreasing the expression of p53 protein. These findings suggest that the combination of GTE and gemigliptin could potentially be used as a prophylactic or therapeutic strategy for TAC-induced nephrotoxicity.
Aunque tacrolimus (TAC) reduce significativamente la incidencia de rechazo de aloinjertos en trasplantes de órganos sólidos, su uso a largo plazo se asocia con un mayor riesgo de nefrotoxicidad inducida por TAC. En este estudio, investigamos los efectos renoprotectores del extracto de té verde (GTE) con o sin el inhibidor de la dipeptidil peptidasa 4, gemigliptina, mediante la evaluación de los niveles de creatinina sérica, la cantidad de proteinuria y la histopatología en la nefrotoxicidad inducida por TAC. La nefrotoxicidad inducida por TAC se indujo mediante inyección intraperitoneal de TAC, el GTE se administró mediante inyección subcutánea y la gemigliptina se administró por vía oral. Los ratones con nefrotoxicidad inducida por TAC mostraron un aumento significativo tanto en los niveles de creatinina sérica como en la proteína en orina de 24 horas. Sin embargo, cuando se trataron con GTE mediante inyección subcutánea, los ratones mostraron una disminución en los niveles de creatinina sérica y en la cantidad de proteinuria. Cuando se combinó GTE con gemigliptina, se observaron efectos renoprotectores adicionales en las evaluaciones bioquímicas, lo que concuerda con la atenuación de la nefrotoxicidad inducida por TAC en histopatología. La expresión de la proteína p53 fue menor en los ratones tratados con la combinación de GTE y gemigliptina en comparación con los ratones con nefrotoxicidad inducida por TAC. Nuestros resultados demuestran que la combinación de tratamiento con GTE y gemigliptina revela efectos renoprotectores sinérgicos al disminuir la expresión de la proteína p53. Estos hallazgos sugieren que la combinación de GTE y gemigliptina podría usarse potencialmente como estrategia profiláctica o terapéutica para la nefrotoxicidad inducida por TAC.
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Animais , Camundongos , Piperidonas/administração & dosagem , Pirimidinas/administração & dosagem , Chá , Extratos Vegetais/administração & dosagem , Tacrolimo/toxicidade , Nefropatias/tratamento farmacológico , Piperidonas/farmacologia , Pirimidinas/farmacologia , Extratos Vegetais/farmacologia , Substâncias Protetoras , Sinergismo Farmacológico , Imunossupressores/toxicidade , Rim/efeitos dos fármacos , Nefropatias/induzido quimicamenteRESUMO
This study shows that the distribution of CYP3A5 alleles (*1, *3, *6 and *7) and genotype-predicted CYP3A5 phenotypes vary significantly across Latin American cohorts (Brazilians and the One Thousand Genomes Admixed American superpopulation), as well as among subcohorts comprising individuals with the highest proportions of Native, European or sub-Saharan African ancestry. Differences in biogeographical ancestry across the study groups are the likely explanation for these results. The differential distribution of CYP3A5 phenotypes has major pharmacogenomic implications, affecting the proportion of individuals carrying high risk CYP3A5 phenotypes for the immunosuppressant tacrolimus and the number of patients that would need to be genotyped to prevent acute rejection in kidney transplant recipients under tacrolimus treatment.
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Farmacogenética , População da América do Sul , Tacrolimo , Humanos , Citocromo P-450 CYP3A/genética , Citocromo P-450 CYP3A/metabolismo , Genótipo , Rejeição de Enxerto/genética , Imunossupressores/efeitos adversos , América Latina , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Tacrolimo/efeitos adversos , Povos Indígenas , População Branca , População da África SubsaarianaRESUMO
Introducción. El tacrolimus es un medicamento inmunosupresor ampliamente usado en trasplante hepático, que presenta una gran variabilidad interindividual la cual se considera asociada a la frecuencia de polimorfismos de CYP3A5 y MDR-1. El objetivo de este estudio fue evaluar la frecuencia de los polimorfismos rs776746, rs2032582 y rs1045642 y su asociación con rechazo clínico y toxicidad farmacológica. Métodos. Se incluyeron pacientes inmunosuprimidos con tacrolimus a quienes se les realizó trasplante hepático en el Hospital San Vicente Fundación Rionegro entre 2020 y 2022, con supervivencia mayor a un mes. Se evaluaron las variables clínicas, rechazo agudo y toxicidad farmacológica. Se secuenciaron los genes de estudio mediante PCR, comparando la expresión o no en cada uno de los pacientes. Resultados. Se identificaron 17 pacientes. El 43 % de los pacientes se clasificaron como CYP3A5*1/*1 y CYP3A5*1/*3, entre los cuales se encontró asociación con aumento en la tasa de rechazo agudo clínico, al comparar con los pacientes no expresivos (100 % vs. 44 %, p=0,05); no hubo diferencias en cuanto a la toxicidad farmacológica u otros desenlaces. Se encontró el polimorfismo rs2032582 en un 50 % y el rs1045642 en un 23,5 % de los pacientes, sin embargo, no se identificó asociación con rechazo u otros eventos clínicos. Conclusiones. Se encontró una asociación entre el genotipo CYP3A5*1/*1 y CYP3A5*1/*3 y la tasa de rechazo clínico. Sin embargo, se requiere una muestra más amplia para validar estos datos y plantear modelos de medicina personalizada.
Introduction. Tacrolimus is an immunosuppressive drug widely used in liver transplantation, which presents great interindividual variability which is considered associated with the frequency of CYP3A5 and MDR-1 polymorphisms. The objective of this study was to evaluate the frequency of the rs776746, rs2032582 and rs1045642 polymorphisms and their association with clinical rejection and drug toxicity. Methods. Immunosuppressed patients with tacrolimus who underwent a liver transplant at the Hospital San Vicente Fundación Rionegro between 2020 and 2022 were included, with survival of more than one month. Clinical variables, acute rejection and pharmacological toxicity were evaluated. The study genes were sequenced by PCR, comparing their expression or not in each of the patients. Results. Seventeen patients were identified. 43% of the patients were classified as CYP3A5*1/*1 and CYP3A5*1/*3, among which an association was found with increased rates of clinical acute rejection when compared with non-expressive patients (100% vs. 44%, p=0.05). There were no differences in drug toxicity or other outcomes. The rs2032582 polymorphism was found in 50% and rs1045642 in 23.5% of patients; however, no association with rejection or other clinical events was identified. Conclusions. An association was found between the CYP3A5*1/*1 and CYP3A5*1/*3 genotype and the clinical rejection rate. However, a larger sample is required to validate these data and propose models of personalized medicine.
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Humanos , Farmacogenética , Transplante de Fígado , Polimorfismo de Nucleotídeo Único , Transplante de Órgãos , Tacrolimo , Rejeição de EnxertoRESUMO
OBJECTIVES: Tacrolimus (TAC) is the most widely used immunosuppressive agent after lung transplantation. Considering that the ciliary beat frequency (CBF) mainly depends on the cytoplasmic calcium concentration and that TAC can affect this due to its binding with the intracellular immunophilin FKBP12, we hypothesized that TAC could also impair the airway mucociliary clearance of rats. METHODS: Sixty rats were divided into two groups (n = 30 each): Control = water; TAC = tacrolimus. After 7, 15 or 30 days of treatment, ten animals from each group were euthanized and the following parameters were studied: mucus transportability, CBF, mucociliary transport velocity (MCTV), and neutral and acid mucus production. RESULTS: There was a significant decrease in CBF (Control vs TAC: 7 days, p = 0.008; 15 days, p = 0.007; 30 days, p = 0.001) and MCTV (Control vs TAC: 7 days, p = 0.004; 15 days, p < 0.001; 30 days, p < 0.001) in all immunosuppressed animals. TAC therapy also caused an increase in acid mucus production at all treatment times (Control vs TAC: 7 days, p = 0.001; 15 days, p = 0.043; 30 days, p = 0.001). CONCLUSIONS: TAC impairs airway mucociliary clearance of rats.
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Transplante de Pulmão , Tacrolimo , Ratos , Animais , Tacrolimo/uso terapêutico , Depuração Mucociliar , Ratos Wistar , Imunossupressores/uso terapêuticoRESUMO
BACKGROUND: Acute rejection remains one of the main complications in the first months after transplantation and may influence long-term outcomes. Tacrolimus has proven its usefulness in solid organ transplants and its monitoring through the application of pharmacokinetic concepts to optimize individual drug therapy. OBJECTIVE: This research proposes to evaluate the tacrolimus pharmacokinetic parameters in patients suspected of acute kidney graft rejection under methylprednisolone pulse therapy. METHODS: Eleven adult tacrolimus-treated renal recipients were selected from a prospective, single-arm, single-center cohort study, with suspicion of acute rejection although in use of methylprednisolone pulses therapy. They were followed up for three months posttransplantation, being tacrolimus trough serum concentrations determined using a chemiluminescent magnetic immunoassay, and pharmacokinetic parameters were estimated by using a nonlinear mixed-effects model implemented by Monolix 2020R1. A tacrolimus trough serum concentration range of 8 to 12 ng.mL-1 was considered therapeutic. RESULTS: Six patients showed acute cellular rejection, and two of them in addition had an antibody- mediated rejection. Tacrolimus trough serum concentration was below the reference range in eight patients. Most patients showed a high tacrolimus concentration intrapatient and pharmacokinetic parameters variability. CONCLUSION: The obtained pharmacokinetics parameters helped in understanding the kidney recipient patients' tacrolimus behavior, assisting in the improvement of individual drug therapy and reducing the risk of acute rejection episodes.
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Tacrolimus (Tac) is currently the most common calcineurin-inhibitor employed in solid organ transplantation. High intra-patient variability (IPV) of Tac (Tac IPV) has been associated with an increased risk of immune-mediated rejection and poor outcomes after kidney transplantation. Few data are available concerning the impact of high Tac IPV in non-kidney transplants. However, even in kidney transplantation, there is still a controversy whether high Tac IPV is indeed detrimental in respect to graft and/or patient survival. This may be due to different methods employed to evaluate IPV and distinct time frames adopted to assess graft and patient survival in those reports published up to now in the literature. Little is also known about the influence of high Tac IPV in the development of other untoward adverse events, update of the current knowledge regarding the impact of Tac IPV in different outcomes following kidney, liver, heart, lung, and pancreas tran splantation to better evaluate its use in clinical practice.
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INTRODUCTION: Despite significant advancements in immunosuppressive regimens and surgical techniques, the prevalence of adverse events related to immunosuppression remains a major challenge affecting the long-term survival rates of pancreas and kidney allografts. AREAS COVERED: This article presents a comprehensive review of the literature and knowledge (Jan/2012-Feb/2023) concerning glucose metabolism disorders and nephrotoxicity associated with tacrolimus and mammalian target of rapamycin inhibitors (mTORi). Novel signaling pathways potentially implicated in these adverse events are discussed. Furthermore, we extensively examine the findings from clinical trials evaluating the efficacy and safety of tacrolimus, mTORi, and steroid minimization. EXPERT OPINION: Tacrolimus-based regimens continue to be the standard treatment following pancreas transplants. However, prolonged use of tacrolimus and mTORi may lead to hyperglycemia and nephrotoxicity. Understanding and interpreting experimental data, particularly concerning novel signaling pathways beyond calcineurin-NFAT and mTOR pathways, can offer valuable insights for therapeutic interventions to mitigate hyperglycemia and nephrotoxicity. Additionally, critically analyzing clinical trial results can identify opportunities for personalized safety-based approaches to minimize side effects. It is imperative to conduct randomized-controlled studies to assess the impact of mTORi use and steroid-free protocols on pancreatic allograft survival. Such studies will aid in tailoring treatment strategies for improved transplant outcomes.
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Hiperglicemia , Transplante de Pâncreas , Humanos , Tacrolimo/efeitos adversos , Transplante de Pâncreas/efeitos adversos , Transplante de Pâncreas/métodos , Imunossupressores/efeitos adversos , Sirolimo/efeitos adversos , Hiperglicemia/induzido quimicamente , Hiperglicemia/tratamento farmacológico , Rejeição de Enxerto/prevenção & controle , Rejeição de Enxerto/tratamento farmacológico , Inibidores de CalcineurinaRESUMO
BACKGROUND: Ototoxicity is a side effect of drugs and medications that usually leads to bilateral and symmetric sensorineural hearing loss that commonly affects the high-frequency range initially, with or preceded by tinnitus. Possible ototoxic side effects of calcineurin inhibitor immunosuppressants have been suggested, but this remains unclear. Therefore, this study aims to evaluate audiological changes in patients undergoing transplantation receiving immunosuppressive treatment with calcineurin inhibitors. METHODS: Prospective cohort study. Adult patients undergoing liver or kidney transplantation treated with calcineurin inhibitors were included. Pure-tone audiometry, distortion product otoacoustic emissions, and the Tinnitus Handicap Inventory questionnaire were completed at baseline, one, three, and six months after transplantation. Hearing thresholds were compared and correlated with plasma concentrations of calcineurin inhibitors. RESULTS: Seventeen patients were included, 59% males, with a median age of 54.7 years (29-68 years). Twelve patients underwent liver transplantation, four underwent kidney transplantation, and one patient underwent both. The medianfollow-up was 5.8 months (4-8 months). Significant pure-tone average shifts were observed in two patients. Both cases presented fluctuations in their hearing levels, which were not bilateral or symmetrical and affected the higher frequencies. All patients received tacrolimus within the therapeutic range during the follow-up period. Three different patients exceeded the expected range once; however, they were rapidly corrected and did not correlate with any changes in hearing. CONCLUSIONS: It appears that tacrolimus does not cause hearing loss when levels are within the therapeutic range for a follow-up period of six months post-transplantation.
INTRODUCCIÓN: La ototoxicidad corresponde a un efecto secundario a agentes terapéuticos que se manifiesta como hipoacusia sensorioneural bilateral simétrica de frecuencias agudas. Se postulan posibles efectos ototóxicos de los inmunosupresores inhibidores de la calcineurina, pero hasta la fecha es aún incierto. El objetivo de este estudio fue evaluar los cambios audiológicos en pacientes trasplantados en tratamiento inmunosupresor con inhibidores de calcineurina. MATERIAL Y MÉTODO: Cohorte prospectiva. Se incluyeron pacientes adultos sometidos a trasplante hepático o renal tratados con inhibidores de calcineurina. Se realizó una evaluación otorrinolaringo-lógica pre-trasplante con audiometría tonal, emisiones otoacústicas por producto de distorsión y cuestionario Tinnitus Handicap Inventory. Se realizó una evaluación audiológica de seguimiento uno, tres y seis meses después del trasplante. Se compararon los umbrales auditivos antes y después del inicio del tratamiento inmunosupresor y se correlacionaron con las concentraciones plasmáticas de IC. RESULTADOS: Se incluyeron 17 pacientes, 59% hombres, con una mediana de edad de 54,7 años. La mediana de seguimiento fue 5,8 meses. Se observaron cambios en el promedio tonal puro en dos pacientes, los cuales no seguían un patrón audiométrico sugerente de ototoxicidad. Todos los pacientes recibieron Tacrolimus dentro del rango terapéutico durante el seguimiento. Tres pacientes diferentes excedieron el rango esperado una vez sin embargo, se corrigieron rápidamente y no se correlacionaron con cambios auditivos, puntaje de tinnitus o emisiones otoacústicas. DISCUSIÓN: Impresiona que Tacrolimus no se asocia a hipoacusia cuando los niveles están en rango terapéutico durante un período de seguimiento de seis meses post trasplante.
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Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Audiometria de Tons Puros , Transplante de Rim , Transplante de Fígado , Inibidores de Calcineurina/efeitos adversos , Ototoxicidade , Imunossupressores/efeitos adversos , Fatores de Tempo , Estudos Prospectivos , Seguimentos , Tacrolimo/efeitos adversos , Perda Auditiva Neurossensorial/induzido quimicamenteRESUMO
Tacrolimus (Tac) is a calcineurin inhibitor commonly used as an immunosuppressor after solid organ transplantation. However, Tac may induce hypertension, nephrotoxicity, and an increase in aldosterone levels. The activation of the mineralocorticoid receptor (MR) is related to the proinflammatory status at the renal level. It modulates the vasoactive response as they are expressed on vascular smooth muscle cells (SMC). In this study, we investigated whether MR is involved in the renal damage generated by Tac and if the MR expressed in SMC is involved. Littermate control mice and mice with targeted deletion of the MR in SMC (SMC-MR-KO) were administered Tac (10 mg/Kg/d) for 10 days. Tac increased the blood pressure, plasma creatinine, expression of the renal induction of the interleukin (IL)-6 mRNA, and expression of neutrophil gelatinase-associated lipocalin (NGAL) protein, a marker of tubular damage (p < 0.05). Our study revealed that co-administration of spironolactone, an MR antagonist, or the absence of MR in SMC-MR-KO mice mitigated most of the unwanted effects of Tac. These results enhance our understanding of the involvement of MR in SMC during the adverse reactions of Tac treatment. Our findings provided an opportunity to design future studies considering the MR antagonism in transplanted subjects.
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TACROLIMUS, a mainstay of immunosuppression after orthotopic heart transplantation (OHT), is associated with a broad range of side effects. Vasoconstriction caused by tacrolimus has been proposed as a mechanism underlying common side effects such as hypertension and renal injury. Neurologic side effects attributed to tacrolimus include headaches, posterior reversible encephalopathy syndrome (PRES), or reversible cerebral vasospasm syndrome (RCVS). Six case reports have been published describing RCVS in the setting of tacrolimus administration after OHT. The authors report a case of perfusion-dependent focal neurologic deficits attributed to tacrolimus-induced RCVS in an OHT recipient.
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Transplante de Coração , Síndrome da Leucoencefalopatia Posterior , Vasoespasmo Intracraniano , Humanos , Tacrolimo/efeitos adversos , Vasoespasmo Intracraniano/induzido quimicamente , Vasoespasmo Intracraniano/diagnóstico por imagem , Síndrome da Leucoencefalopatia Posterior/induzido quimicamente , Síndrome da Leucoencefalopatia Posterior/diagnóstico por imagem , Estado Terminal , Perfusão/efeitos adversos , Transplante de Coração/efeitos adversosRESUMO
Purpose: Tacrolimus is recommended by KDIGO Clinical Practice Guidelines as an initial therapy for the treatment of membranous nephropathy (MN). However, little is known about the factors that influence response and recurrence of the disease after tacrolimus therapy, and there are limited data regarding the duration of tacrolimus treatment. Here, we present a real-world retrospective cohort study of 182 MN patients treated with tacrolimus, aiming to assess the efficacy and safety of tacrolimus in the treatment of MN. Patients and Methods: The clinical data of 182 patients with MN treated with tacrolimus and followed up for at least one year were analyzed retrospectively for the efficacy and safety of tacrolimus. Results: The mean follow-up period was 27.3 (19.3-41.6) months. A total of 154 patients (84.6%) achieved complete or partial remission, and 28 patients (15.4%) did not. Multivariate Cox regression analysis showed that male and higher baseline BMI were independently associated with lower, while higher serum albumin was associated with higher probability of remission. Among the responders, 56 patients (36.4%) relapsed. After adjustments for age and sex, Cox regression analysis revealed that the longer period of full-dose tacrolimus was administered, the lower the incidence of relapse. However, high levels of serum creatinine and proteinuria at the onset of tacrolimus discontinuation were risk factors for relapse. During the treatment of tacrolimus, a decline in renal function (≥50% increase in serum creatinine after the onset of tacrolimus treatment) was the most common adverse reaction, observed in 20 (11.0%) patients, followed by elevated blood glucose and infection, but the latter two occurred mostly during treatment with tacrolimus plus corticosteroids. Conclusion: Tacrolimus is effective in the treatment of MN, but the relapse rate is high. Clinical studies with larger sample sizes are needed to further explore the use of tacrolimus in the treatment of membranous nephropathy.
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The activity of the Na+-Cl- cotransporter (NCC) in the distal convoluted tubule (DCT) is finely tuned by phosphorylation networks involving serine/threonine kinases and phosphatases. While much attention has been paid to the With-No-lysine (K) kinase (WNK)- STE20-related Proline Alanine rich Kinase (SPAK)/Oxidative Stress Responsive kinase 1 (OSR1) signaling pathway, there remain many unanswered questions regarding phosphatase-mediated modulation of NCC and its interactors. The phosphatases shown to regulate NCC's activity, directly or indirectly, are protein phosphatase 1 (PP1), protein phosphatase 2A (PP2A), calcineurin (CN), and protein phosphatase 4 (PP4). PP1 has been suggested to directly dephosphorylate WNK4, SPAK, and NCC. This phosphatase increases its abundance and activity when extracellular K+ is increased, which leads to distinct inhibitory mechanisms towards NCC. Inhibitor-1 (I1), oppositely, inhibits PP1 when phosphorylated by protein kinase A (PKA). CN inhibitors, like tacrolimus and cyclosporin A, increase NCC phosphorylation, giving an explanation to the Familial Hyperkalemic Hypertension-like syndrome that affects some patients treated with these drugs. CN inhibitors can prevent high K+-induced dephosphorylation of NCC. CN can also dephosphorylate and activate Kelch-like protein 3 (KLHL3), thus decreasing WNK abundance. PP2A and PP4 have been shown in in vitro models to regulate NCC or its upstream activators. However, no studies in native kidneys or tubules have been performed to test their physiological role in NCC regulation. This review focuses on these dephosphorylation mediators and the transduction mechanisms possibly involved in physiological states that require of the modulation of the dephosphorylation rate of NCC.
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Background and Aim: Keratoconjunctivitis sicca (KCS) is predominantly an immune-mediated chronic inflammatory ocular disease that is commonly diagnosed in dogs. This study aimed to compare the conventional use of topical immunosuppressant tacrolimus 0.03% eye drops and a new therapy injectable homologous platelet-rich plasma (HPRP) into the third eyelid gland and inferior and superior palpebral conjunctiva of dogs with KCS. Materials and Methods: A total of 66 eyes from 33 dogs were evaluated. The eyes were divided into three equal groups: Negative control group, tacrolimus group (TG), and homologous platelet-rich plasma group (HPRPG). The animals were evaluated using the Schirmer's tear test-1 (STT-1), osmolarity test (OT), strip meniscometry test (SMT), tear film break-up test (TBUT), fluorescein test, lissamine green test (LGT), and cytological and histopathological analyses. Results: In TG, there was a significant increase (p < 0.05) in the STT-1 and SMT values, and goblet cell count in the palpebral conjunctiva by the end of the study. In HPRPG, 36% (four dogs) received three applications, 55% (six dogs) received two applications, and 9% (one dog) received one application before the initial ocular signs improved. There was a significant decrease (p < 0.05) in the lymphocyte and neutrophil counts of the palpebral conjunctiva in HPRPG than in TG. Both groups showed equivalent improvements in TBUT, OT, and LGT values. Conclusion: Tacrolimus 0.03% eye drops were more efficient than HPRP in increasing tear production and the number of goblet cells. However, injectable HPRP was more efficient than tacrolimus in decreasing the number of conjunctival inflammatory cells. Treatment with injectable HPRP requires an average of two to three applications, is safe and feasible, and can be used as a cheaper alternative or as an adjuvant to conventional treatment with topical immunosuppressants.
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Background: Kidney transplantation (KTx) requires immunosuppressive drugs such as Tacrolimus (TAC) which is mainly metabolized by CYP3A5. TAC is routinely monitored by trough levels (C0) although it has not shown to be a reliable marker. The area-under-curve (AUC) is a more realistic measure of drug exposure, but sampling is challenging in pediatric patients. Limited-sampling strategies (LSS) have been developed to estimate AUC. Herein, we aimed to determine AUC(0-24) and CYP3A5 genotype in Chilean pediatric kidney recipients using extended-release TAC, to evaluate different LSS-AUC(0-24) formulas and dose requirements. Patients and methods: We analyzed pediatric kidney recipients using different extended-release TAC brands to determine their trapezoidal AUC(0-24) and CYP3A5 genotypes (SNP rs776746). Daily TAC dose (TAC-D mg/kg) and AUC(0-24) normalized by dose were compared between CYP3A5 expressors (*1/*1 and *1/*3) and non-expressors (*3/*3). We evaluated the single and combined time-points to identify the best LSS-AUC(0-24) model. We compared the performance of this model with two pediatric LSS-AUC(0-24) equations for clinical validation. Results: Fifty-one pharmacokinetic profiles were obtained from kidney recipients (age 13.1 ± 2.9 years). When normalizing AUC(0-24) by TAC-D significant differences were found between CYP3A5 expressors and non-expressors (1701.9 vs. 2718.1 ng*h/mL/mg/kg, p < 0.05). C0 had a poor fit with AUC(0-24) (r 2 = 0.5011). The model which included C0, C1 and C4, showed the best performance to predict LSS-AUC(0-24) (r 2 = 0.8765) and yielded the lowest precision error (7.1% ± 6.4%) with the lowest fraction (9.8%) of deviated AUC(0-24), in comparison to other LSS equations. Conclusion: Estimation of LSS-AUC(0-24) with 3 time-points is an advisable and clinically useful option for pediatric kidney recipients using extended-release TAC to provide better guidance of decisions if toxicity or drug inefficacy is suspected. The different CYP3A5 genotypes associated with variable dose requirements reinforce considering genotyping before KTx. Further multi-centric studies with admixed cohorts are needed to determine the short- and long-term clinical benefits.
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Purpose: Conjunctival melanoma is a rare ocular tumor. We report a case of ocular conjunctival melanoma during topical immunosuppression, after a corneal transplant from a donor with metastatic melanoma. Observation: A 59-year-old white male presented with a progressive nonpigmented conjunctival lesion in his right eye. He had previously undergone two penetrating keratoplasties, and he was being treated with topical immunosuppression with 0.03% tacrolimus (Ophthalmos Pharma; Sao Paulo, SP/Brazil). The histopathology evaluation revealed the nodule to be a conjunctival epithelioid melanoma. The donor's death cause was disseminated melanoma. Conclusion and importance: The correlation between cancer and systemic immunosuppression after a solid organ transplant is widely known. The local influence, however, has not been reported. In this case, a causal relationship was not established. The correlation between conjunctival melanoma, exposure to topical tacrolimus immunosuppressive therapy, and the malignance characteristic of donor cornea should be better evaluated.
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OBJECTIVE: This study aimed to investigate the effects of FK506 on experimental sepsis immunopathology. It investigated the effect of FK506 on leukocyte recruitment to the site of infection, systemic cytokine production, and organ injury in mice with sepsis. METHODS: Using a murine cecal ligation and puncture (CLP) peritonitis model, the experiments were performed with wild-type (WT) mice and mice deficient in the gene Nfat1 (Nfat1-/-) in the C57BL/6 background. Animals were treated with 2.0 mg/kg of FK506, subcutaneously, 1 h before the sepsis model, twice a day (12 h/12 h). The number of bacteria colony forming units (CFU) was manually counted. The number of neutrophils in the lungs was estimated by the myeloperoxidase (MPO) assay. The expression of CXCR2 in neutrophils was determined using flow cytometry analysis. The expression of inflammatory cytokines in macrophage was determined using ELISA. The direct effect of FK506 on CXCR2 internalization was evaluated using HEK-293T cells after CXCL2 stimulation by the BRET method. RESULTS: FK506 treatment potentiated the failure of neutrophil migration into the peritoneal cavity, resulting in bacteremia and an exacerbated systemic inflammatory response, which led to higher organ damage and mortality rates. Failed neutrophil migration was associated with elevated CXCL2 chemokine plasma levels and lower expression of the CXCR2 receptor on circulating neutrophils compared with non-treated CLP-induced septic mice. FK506 did not directly affect CXCL2-induced CXCR2 internalization by transfected HEK-293 cells or mice neutrophils, despite increasing CXCL2 release by LPS-treated macrophages. Finally, the CLP-induced response of Nfat1-/- mice was similar to those observed in the Nfat1+/+ genotype, suggesting that the FK506 effect is not dependent on the NFAT1 pathway. CONCLUSION: Our data indicate that the increased susceptibility to infection of FK506-treated mice is associated with failed neutrophil migration due to the reduced membrane availability of CXCR2 receptors in response to exacerbated levels of circulating CXCL2.
Assuntos
Neutrófilos , Sepse , Humanos , Camundongos , Animais , Tacrolimo/farmacologia , Tacrolimo/uso terapêutico , Células HEK293 , Camundongos Endogâmicos C57BL , Sepse/metabolismo , Infiltração de NeutrófilosRESUMO
BACKGROUND: Losing-salt tubulopathies, such as Bartter syndrome, are rare and usually inherited due to mutations of tubular reabsorption channels of the nephrons. Despite its scarcity, some cases of acquired losing-salt tubulopathies have been described. In this case report, we discuss the main aspects of Bartter syndrome and present a rare pediatric case of probable tacrolimusinduced Bartter-like syndrome in a renal transplanted boy. CASE PRESENTATION: A ten-year-old male patient with end-stage renal disease due to endo and extra capillary glomerulonephritis was submitted to renal transplantation from a deceased donor. The post-operatory evolution was satisfactory with normalization of serum creatinine levels, mild hypertension, and the absence of metabolic disorders. The immunosuppression protocol included tacrolimus (0.3 mg/kg/day), mycophenolate (455 mg/m2/day) and prednisone (0.5 mg/kg/day). Two months later, the patient was hospitalized due to vomiting, dehydration, intense hypokalemia (1.3 mEq/L), hyponatremia (125 mEq/L), and hypochloremia (84 mmol/L). During hospitalization, he evolved with polydipsia (3000 mL/day) and polyuria (120-160 mL/m2/h) associated with major elevation of urinary potassium excretion, hypercalciuria, mild metabolic alkalosis, hyperfiltration, and proteinuria. The tacrolimus dose was reduced under the suspicion of tubular dysfunction, leading to a better metabolic profile. However, the patient developed a Banff IIb graft rejection, which required pulse therapy and elevation of tacrolimus and mycophenolate doses. Recovery of renal function parameters occurred, but the metabolic disorders worsened following tacrolimus dose elevation. The patient required chronic potassium, chloride, and sodium replacement. CONCLUSION: After administering immunosuppressive medications, physicians should be aware of the possibility of Bartter-like or other losing-salt tubulopathies syndromes that can affect metabolic homeostasis. The suspicion must always be considered in the case of a transplanted patient who presents dehydration and hydroelectrolytic disorders right after the commencement of nephrotoxic immunosuppressive drugs, including tacrolimus and cyclosporine.
Assuntos
Síndrome de Bartter , Transplante de Rim , Masculino , Criança , Humanos , Síndrome de Bartter/induzido quimicamente , Síndrome de Bartter/diagnóstico , Síndrome de Bartter/complicações , Tacrolimo/efeitos adversos , Transplante de Rim/efeitos adversos , Desidratação/complicações , Desidratação/tratamento farmacológico , Imunossupressores/efeitos adversos , Potássio/uso terapêuticoRESUMO
Abstract Voriconazole increases tacrolimus blood concentration significantly when coadministrated. The recommendation of reducing tacrolimus to 1/3 in voriconazole package insert seems not to be satisfactory in clinical practice. In vitro studies demonstrated that the magnitude of inhibition depends on the concentration of voriconazole, while voriconazole exposure is determined by the genotype status of CYP2C19. CYP2C19 gene polymorphism challenges the management of drug-drug interactions(DDIs) between voriconazole and tacrolimus. This work aimed to predict the impact of CYP2C19 polymorphism on the DDIs by using physiologically based pharmacokinetics (PBPK) models. The precision of the developed voriconazole and tacrolimus models was reasonable by evaluating the pharmacokinetic parameters fold error, such as AUC0-24, Cmax and tmax. Voriconazole increased tacrolimus concentration immediately in all population. The simulated duration of DDIs disappearance after voriconazole withdrawal were 146h, 90h and 66h in poor metabolizers (PMs), intermediate metabolizers (IMs) and extensive metabolizers(EMs), respectively. The developed and optimized PBPK models in this study can be applied to assit the dose adjustment for tacrolimus with and without voriconazole.