RESUMO
BACKGROUND: Whole-blood therapeutic drug monitoring of tacrolimus is conducted to maintain tacrolimus concentrations within a safe and effective range. Changes in hematocrit cause variability in blood concentrations of tacrolimus because it is highly bound to erythrocytes. Measuring plasma concentrations may eliminate this variability; however, current methods have limitations owing to the use of cross-reactive immunoassays, plasma separation at nonbiological temperatures, and lack of clinical validation. This study aimed to develop and validate a clinically applicable method to measure plasma tacrolimus concentrations in renal transplant recipients and to examine the concentration differences between genotypic CYP3A5 expressors and nonexpressors. METHODS: Plasma tacrolimus concentrations were measured in 9 stable renal transplant recipients who were genotypic CYP3A5 expressors or nonexpressors. Tacrolimus was extracted from plasma using solid-phase extraction, and liquid chromatography-tandem mass spectrometry was used for detection and quantitation. RESULTS: This assay was sensitive, selective, and linear between 100 and 5000 ng/L, with intraassay and interassay imprecision and inaccuracy <10% and <5% respectively. The extraction recovery of tacrolimus and ascomycin was 74%. Matrix ion suppression effects were 31.5% and 35% with overall recovery of 50.6% and 48.3% for tacrolimus and ascomycin, respectively. Whole-blood concentrations accounted for approximately 46% of the variation in plasma concentrations in CYP3A5 expressors and nonexpressors. No difference in dose-adjusted whole-blood and plasma concentrations was observed between CYP3A5 expressors and nonexpressors. CONCLUSIONS: This assay is clinically applicable with excellent performance and demonstrated that tacrolimus plasma concentrations highly correlated with whole-blood concentrations.
Assuntos
Transplante de Rim , Espectrometria de Massa com Cromatografia Líquida , Humanos , Cromatografia Líquida , Citocromo P-450 CYP3A/genética , Tacrolimo , Espectrometria de Massas em TandemRESUMO
BACKGROUND: The presence and extent of left ventricular hypertrophy (LVH) is a major determinant of symptoms in patients with hypertrophic cardiomyopathy (HCM). There is increasing evidence to suggest that myocardial energetic impairment represents a central mechanism leading to LVH in HCM. There is currently a significant unmet need for disease-modifying therapy that regresses LVH in HCM patients. Perhexiline, a potent carnitine palmitoyl transferase-1 (CPT-1) inhibitor, improves myocardial energetics in HCM, and has the potential to reduce LVH in HCM. OBJECTIVE: The primary objective is to evaluate the effects of perhexiline treatment on the extent of LVH, in symptomatic HCM patients with at least moderate LVH. METHODS/DESIGN: RESOLVE-HCM is a prospective, multicenter double-blind placebo-controlled randomized trial enrolling symptomatic HCM patients with at least moderate LVH. Sixty patients will be randomized to receive either perhexiline or matching placebo. The primary endpoint is change in LVH, assessed utilizing cardiovascular magnetic resonance (CMR) imaging, after 12-months treatment with perhexiline. SUMMARY: RESOLVE-HCM will provide novel information on the utility of perhexiline in regression of LVH in symptomatic HCM patients. A positive result would lead to the design of a Phase 3 clinical trial addressing long-term effects of perhexiline on risk of heart failure and mortality in HCM patients.
Assuntos
Cardiomiopatia Hipertrófica/tratamento farmacológico , Cardiomiopatia Hipertrófica/fisiopatologia , Fármacos Cardiovasculares/uso terapêutico , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/prevenção & controle , Perexilina/uso terapêutico , Adulto , Cardiomiopatia Hipertrófica/diagnóstico por imagem , Método Duplo-Cego , Ecocardiografia , Feminino , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Imageamento por Ressonância Magnética , Masculino , Estudos ProspectivosRESUMO
Anthracyclines are used to treat solid and haematological cancers, particularly breast cancers, lymphomas and childhood cancers. Myelosuppression and cardiotoxicity are the primary toxicities that limit treatment duration and/or intensity. Cardiotoxicity, particularly heart failure, is a leading cause of morbidity and mortality in cancer survivors. Cumulative anthracycline dose is a significant predictor of cardiotoxicity risk, suggesting a role for anthracycline pharmacokinetic variability. Population pharmacokinetic modelling in children has shown that doxorubicin clearance in the very young is significantly lower than in older children, potentially contributing to their higher risk of cardiotoxicity. A model of doxorubicin clearance based on body surface area and age offers a patient-centred dose-adjustment strategy that may replace the current disparate initial-dose selection tools, providing a rational way to compensate for pharmacokinetic variability in children aged <7 years. Population pharmacokinetic models in adults have not adequately addressed older ages, obesity, hepatic and renal dysfunction, and potential drug-drug interactions to enable clinical application. Although candidate gene and genome-wide association studies have investigated relationships between genetic variability and anthracycline pharmacokinetics or clinical outcomes, there have been few clinically significant reproducible associations. Precision-dosing of anthracyclines is currently hindered by lack of clinically useful pharmacokinetic targets and models that predict cumulative anthracycline exposures. Combined with known risk factors for cardiotoxicity, the use of advanced echocardiography and biomarkers, future validated pharmacokinetic targets and predictive models could facilitate anthracycline precision dosing that truly maximises efficacy and provides individualised early intervention with cardioprotective therapies in patients at risk of cardiotoxicity.
Assuntos
Neoplasias da Mama , Neoplasias , Adulto , Idoso , Antraciclinas/efeitos adversos , Antibióticos Antineoplásicos/efeitos adversos , Neoplasias da Mama/tratamento farmacológico , Cardiotoxicidade/etiologia , Criança , Feminino , Estudo de Associação Genômica Ampla , Humanos , Pessoa de Meia-Idade , Neoplasias/tratamento farmacológicoRESUMO
AIMS: Long-term use of the immunosuppressant tacrolimus is limited by nephrotoxicity. Following renal transplantation, the risk of nephrotoxicity may be determined more by allograft than by blood tacrolimus concentrations, and thus may be affected by donor CYP3A5 and ABCB1 genetics. Little is known regarding factors that determine tacrolimus intrarenal exposure. METHODS: This study investigated the relationship between trough blood (C0Blood ) and allograft (CGraft ) tacrolimus concentrations and tacrolimus dose, haematocrit, genetics, acute nephrotoxicity, rejection status, delayed graft function, and time post-transplant. C0Blood and CGraft were quantified in 132 renal transplant recipients together with recipient and donor CYP3A5 (rs776746) and ABCB1 3435 (rs1045642) genotypes. RESULTS: C0Blood ranged from 2.6 to 52.3 ng/mL and CGraft from 33 to 828 pg/mg tissue. Adjusting for dose, recipients who were CYP3A5 expressors had lower C0Blood compared to nonexpressors, whilst delayed graft function was associated with higher C0Blood . Linear regression showed that the significant predictors of CGraft were C0Blood (point-wise P = 7 × 10-10 ), dose (P = .004) acute nephrotoxicity (P = .002) and an interaction between C0Blood and acute tacrolimus nephrotoxicity (P = .0002), with an adjusted r2 = 0.35 and no contribution from donor or recipient CYP3A5 or ABCB1 genotype. The association between CGraft and acute nephrotoxicity depended on one very high CGraft (828 pg/mg tissue). CONCLUSIONS: Recipient and donor CYP3A5 and ABCB1 3435C>T genotypes are not determinants of allograft tacrolimus exposure in kidney transplant recipients. However, tacrolimus dose and C0Blood were significant predictors of CGraft , and the relationship between C0Blood and CGraft appeared to differ in the presence or absence of acute nephrotoxicity.
Assuntos
Transplante de Rim , Tacrolimo , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Aloenxertos , Citocromo P-450 CYP3A/genética , Genótipo , Humanos , Imunossupressores/efeitos adversos , Polimorfismo de Nucleotídeo Único , Tacrolimo/efeitos adversos , TransplantadosRESUMO
BACKGROUND: CYP3A4/5 and P-glycoprotein (P-gp, ABCB1) affect tacrolimus (TAC) exposure in T cells and kidney cells. Genetic variability of these genes has been widely studied for effects on acute rejection and kidney function after transplantation, but findings remain contradictory. In addition, cytochrome P450 reductase (POR) is important for CYP3A4/5 activity, and the pregnane X receptor (NR1I2) regulates CYP3A4/5 and P-gp expression. However, the relationship between POR and NR1I2 genetics and acute rejection and kidney function has not been extensively investigated. OBJECTIVE: The aim of this study was to investigate the effect of ABCB1 (61A>G, 1199G>A, 1236C>T, 2677G>T, 3435C>T), CYP3A4*22, CYP3A5*3, NR1I2 (8055C>T, 63396C>T) and POR*28 genotypes/haplotypes on acute rejection and kidney function in the first 3 months after transplant. PARTICIPANTS AND METHODS: The study included 165 kidney transplant recipients, who received TAC, mycophenolate and prednisolone, and 129 donors. TAC dose was adjusted to target trough blood concentrations of 8-15 ng/ml by therapeutic drug monitoring. Recipient and donor genotype/haplotype differences in acute rejection incidence within the first 2 weeks after transplant were assessed by logistic regression, adjusting for induction therapy, human leucocyte antigen mismatches, kidney transplant number, peak panel-reactive antibodies and donor type. Recipient and donor genotype/haplotype differences in estimated glomerular filtration rate in the first 3 months after transplant were assessed by linear mixed effects analysis, adjusting for acute rejection, delayed graft function and donor type. RESULTS: No genetic factors significantly affected acute rejection or estimated glomerular filtration rate after correction for multiple comparisons (P>0.004). CONCLUSION: Recipient and donor dispositional genetics had no significant effect on short-term clinical outcomes in kidney transplant patients receiving TAC therapeutic drug monitoring.
Assuntos
Citocromo P-450 CYP3A/genética , Sistema Enzimático do Citocromo P-450/genética , Rejeição de Enxerto/tratamento farmacológico , Imunossupressores/administração & dosagem , Receptor de Pregnano X/genética , Tacrolimo/administração & dosagem , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Feminino , Taxa de Filtração Glomerular/efeitos dos fármacos , Rejeição de Enxerto/genética , Humanos , Imunossupressores/farmacologia , Transplante de Rim , Masculino , Variantes Farmacogenômicos , Polimorfismo de Nucleotídeo Único , Tacrolimo/farmacologia , Doadores de TecidosRESUMO
The immunosuppressant cyclosporin is a P-glycoprotein (P-gp) substrate whose impaired function has been associated with an increased risk of cyclosporin-induced nephrotoxicity following renal transplantation. This study investigated the relationship between blood and allograft cyclosporin concentration, and the effect of P-gp expression. Fifty biopsy samples were obtained from 39 renal transplant recipients who received cyclosporin as part of maintenance immunosuppression. Blood cyclosporin concentrations (2 hours postdose) were obtained from clinical records, matching allograft cyclosporin concentrations were measured in frozen biopsy tissue by liquid chromatography-tandem mass spectrometry, and allograft P-gp expression was assessed by immunohistochemistry. Blood and allograft cyclosporin concentrations in the 1st month post-transplantation ranged from 505-2005 µg/L and 0.01-16.7 ng/mg tissue, respectively. Dose was the only significant predictor of allograft cyclosporin concentrations (adjusted R2 = .24, F-statistic = 11.52, P = .0019), with no effect of P-gp expression or blood cyclosporin concentrations. P-gp expression is not the major determinant of allograft cyclosporin concentrations.
Assuntos
Inibidores de Calcineurina/farmacocinética , Ciclosporina/farmacocinética , Rejeição de Enxerto/prevenção & controle , Transplante de Rim/efeitos adversos , Subfamília B de Transportador de Cassetes de Ligação de ATP/análise , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Adolescente , Adulto , Idoso , Aloenxertos/química , Aloenxertos/imunologia , Aloenxertos/metabolismo , Aloenxertos/patologia , Biópsia , Inibidores de Calcineurina/administração & dosagem , Inibidores de Calcineurina/isolamento & purificação , Ciclosporina/administração & dosagem , Ciclosporina/isolamento & purificação , Relação Dose-Resposta a Droga , Feminino , Rejeição de Enxerto/sangue , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Humanos , Rim/química , Rim/imunologia , Rim/metabolismo , Rim/patologia , Masculino , Pessoa de Meia-Idade , Transplante Homólogo/efeitos adversos , Adulto JovemRESUMO
BACKGROUND: There are inconsistent findings regarding the relationship between trough whole blood tacrolimus concentration (TAC C0) and acute kidney rejection in recipients undergoing TAC therapeutic drug monitoring (TDM). However, studies have not always assessed TAC C0 at the time of rejection or accounted for variability in hematocrit. Therefore, this study aimed to investigate the temporal relationship between TAC C0 and acute rejection, including when accounting for variation in hematocrit. METHODS: For 38 recipients who developed biopsy-proven acute rejection (BPAR) in the first 14 days after kidney transplantation, daily TAC C0 from TDM and hematocrit was collected from case notes. Differences in log10-transformed TAC C0 between the day of BPAR (log Cr), 1 day before BPAR (log Cr-1), and 2 days before BPAR (log Cr-2) and the combined median concentrations for the days preceding these (log Cprior) were examined by repeated-measures analysis of variance with Dunnett post hoc testing. Generalized linear mixed-effects regression (glmer) examined the ability of TAC C0 to predict acute rejection episodes with and without controlling for hematocrit. RESULTS: Log Cr-1 [mean difference (95% confidence interval) = -0.13 (-0.21 to -0.048), post hoc P = 0.002] and log Cr [-0.13 (-0.24 to -0.025), post hoc P = 0.013] were significantly lower than log Cprior. TAC C0 was a significant (P = 0.0078) predictor of rejection episodes (area under the receiver operating characteristic curve = 0.79) only in glmer models accounting for variability in hematocrit. CONCLUSIONS: In recipients who developed BPAR, there was a significant temporal relationship between TAC C0 and BPAR incidence under TAC TDM that may not be detected in cross-sectional studies, especially if variability in hematocrit is not addressed. This supports a TAC C0-rejection relationship, which differs between recipients, and may explain why some recipients do or do not experience rejection within or below the TDM range, respectively. However, studies with larger sample sizes are needed to confirm this finding.
Assuntos
Rejeição de Enxerto/sangue , Imunossupressores/sangue , Tacrolimo/sangue , Monitoramento de Medicamentos/métodos , Humanos , Transplante de Rim , Fatores de TempoRESUMO
AIMS: Although therapeutic drug monitoring of plasma mycophenolic acid (MPA) concentrations has been recommended to individualize dosage in transplant recipients, little is known regarding lymphocyte concentrations of MPA, where MPA inhibits inosine monophosphate dehydrogenase (IMPDH). This study investigated the utility of measuring predose MPA concentrations in peripheral blood mononuclear cells (C0C ) and predose IMPDH activity, as predictors of graft rejection in renal transplant recipients. METHODS: Forty-eight patients commencing mycophenolate mofetil (1 g twice daily) in combination with tacrolimus and prednisolone were recruited. Blood was collected for determination of trough total (C0P ) and unbound (C0u ) plasma MPA concentrations. Peripheral blood mononuclear cells were isolated for determination of C0C and IMPDH activity. The incidence of rejection within 2 days of sample collection was determined histologically and classified according to the Banff 2007 criteria. RESULTS: There was no association between MPA C0C and C0P (rs = 0.28, P = 0.06), however, MPA C0C were weakly correlated with MPA C0u (rs = 0.42, P = 0.013). Multivariate analysis indicated that MPA C0C was the only covariate independently associated with rejection (FDR-adjusted P = 0.033). The receiver operating characteristic area under the curve (AUC) for the prediction of severe rejection using MPA C0C was 0.75 (P = 0.013), with 73% sensitivity and specificity at a C0C threshold of 0.5 ng 10-7 cells. However, predose IMPDH activity was not a predictor of rejection (P > 0.15). CONCLUSIONS: MPA C0C measurement within the early post-transplant period may be useful to facilitate early titration of MPA dosing to significantly reduce rejection.
Assuntos
Monitoramento de Medicamentos/métodos , Rejeição de Enxerto/diagnóstico , Imunossupressores/farmacocinética , Transplante de Rim/efeitos adversos , Leucócitos Mononucleares/química , Ácido Micofenólico/farmacocinética , Adulto , Idoso , Área Sob a Curva , Quimioterapia Combinada/métodos , Ensaios Enzimáticos , Feminino , Rejeição de Enxerto/sangue , Rejeição de Enxerto/epidemiologia , Rejeição de Enxerto/prevenção & controle , Humanos , IMP Desidrogenase/antagonistas & inibidores , IMP Desidrogenase/imunologia , Imunossupressores/administração & dosagem , Imunossupressores/análise , Incidência , Masculino , Pessoa de Meia-Idade , Ácido Micofenólico/administração & dosagem , Ácido Micofenólico/análise , Prednisolona/administração & dosagem , Prognóstico , Estudos Prospectivos , Sensibilidade e Especificidade , Tacrolimo/administração & dosagem , Transplantados , Adulto JovemRESUMO
BACKGROUND: The polymorphic nature of cytochrome P450 2D6 has made therapeutic drug monitoring of the anti-anginal agent perhexiline a compulsory step in reducing adverse events associated with plasma concentrations above the therapeutic range (0.15-0.60 mg/L). The aim of this study was to develop a high-performance liquid chromatography-mass spectrometry/mass spectrometry method for the determination of plasma perhexiline concentrations and its major metabolite cis-hydroxy-perhexiline to reduce sample extraction procedures and improve sample turnaround times. METHODS: The method was validated by determining the precision and accuracy of calibrators and quality control material, comparing quality assurance program samples and patient samples measured by a previously reported liquid-liquid extraction fluorescence (FL) detection high-performance liquid chromatography method and performing matrix effects investigations. RESULTS: Replicates of calibrators at concentrations of 3.00 and 0.05 mg/L demonstrated imprecision of <10.8% and inaccuracy of <8.2% for perhexiline and <10.1% and <4.5% for cis-hydroxy-perhexiline, respectively. All samples measured by the 2 methods (n = 102) demonstrated Deming regression of perhexiline = 1.20 FL + 0.00 (Sy.x = 0.08, 1/slope = 0.67); cis-hydroxy-perhexiline = 1.48 FL - 0.20 (Sy.x = 0.40, 1/slope = 0.67). CONCLUSIONS: The assay performance was deemed acceptable and integrated into the routine therapeutic drug monitoring program of the department.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Monitoramento de Medicamentos/métodos , Perexilina/análogos & derivados , Espectrometria de Massas em Tandem/métodos , Calibragem , Citocromo P-450 CYP2D6/genética , Humanos , Extração Líquido-Líquido , Perexilina/sangue , Polimorfismo Genético , Reprodutibilidade dos TestesRESUMO
PURPOSE: Perhexiline is a prophylactic anti-ischaemic agent with weak calcium antagonist effect which has been increasingly utilised in the management of refractory angina. The metabolic clearance of perhexiline is modulated by CYP2D6 metaboliser status and stereoselectivity. The current study sought to (1) determine whether the acute accumulation of perhexiline in the myocardium is stereoselective and (2) investigate the relationship between duration of short-term therapy and the potential stereoselective effects of perhexiline within myocardium. METHOD: Patients (n = 129) from the active arm of a randomised controlled trial of preoperative perhexiline in cardiac surgery were treated with oral perhexiline for a median of 9 days. Correlates of atrial and ventricular concentrations of enantiomers were sought via univariate followed by multivariate analyses. RESULTS: Myocardial uptake of both (+) and (-) perhexiline was greater in ventricles than in atria, and there was more rapid clearance of (-) than (+) perhexiline. The main determinants of atrial uptake of both (+) and (-) perhexiline were the plasma concentrations [(+) perhexiline: ß = -0.256, p = 0.015; (-) perhexiline: ß = -0.347, p = 0.001] and patients' age [(+) perhexiline: ß = 0.300, p = 0.004; (-) perhexiline: ß = 0.288, p = 0.005]. Atrial uptake of (+) enantiomer also varied directly with duration of therapy (ß = 0.228, p = 0.025), while atrial uptake of (-) perhexiline varied inversely with simultaneous heart rate (ß = -0.240, p = 0.015). CONCLUSION: (1) Uptake of both perhexiline enantiomers into atrium is greater with advanced age and displays evidence of both saturability and minor stereoselectivity. (2) Atrial uptake of (-) perhexiline may selectively modulate heart rate reduction.
Assuntos
Fármacos Cardiovasculares/farmacocinética , Miocárdio/metabolismo , Perexilina/farmacocinética , Administração Oral , Idoso , Fármacos Cardiovasculares/administração & dosagem , Fármacos Cardiovasculares/química , Átrios do Coração/metabolismo , Ventrículos do Coração/metabolismo , Humanos , Pessoa de Meia-Idade , Perexilina/administração & dosagem , Perexilina/química , Estereoisomerismo , Distribuição TecidualRESUMO
1. Perhexiline, a chiral anti-anginal agent, may be useful to develop new cardiovascular therapies, despite its potential hepatotoxicity. 2. This study compared Dark Agouti (DA) and Sprague-Dawley (SD) rats, as models of perhexiline's metabolism and hepatotoxicity in humans. Rats (n = 4/group) received vehicle or 200 mg/kg/d of racemic perhexiline maleate for 8 weeks. Plasma and liver samples were collected to determine concentrations of perhexiline and its metabolites, hepatic function and histology. 3. Median (range) plasma and liver perhexiline concentrations in SD rats were 0.09 (0.04-0.13) mg/L and 5.42 (0.92-8.22) ng/mg, respectively. In comparison, DA rats showed higher (p < 0.05) plasma 0.50 (0.16-1.13) mg/L and liver 24.5 (9.40-54.7) ng/mg perhexiline concentrations, respectively, 2.5- and 3.7-fold higher cis-OH-perhexiline concentrations, respectively (p < 0.05), and lower plasma metabolic ratio (0.89 versus 1.55, p < 0.05). In both strains, the (+):(-) enantiomer ratio was 2:1. Perhexiline increased plasma LDH concentrations in DA rats (p < 0.05), but had no effect on plasma biochemistry in SD rats. Liver histology revealed lower glycogen content in perhexiline-treated SD rats (p < 0.05), but no effects on lipid content in either strain. 4. DA rats appeared more similar to humans with respect to plasma perhexiline concentrations, metabolic ratio, enantioselective disposition and biochemical changes suggestive of perhexiline-induced toxicity.
Assuntos
Oxirredutases do Álcool/metabolismo , Fármacos Cardiovasculares/metabolismo , Fígado/efeitos dos fármacos , Modelos Animais , Perexilina/metabolismo , Ratos Sprague-Dawley , Animais , Fármacos Cardiovasculares/toxicidade , Família 2 do Citocromo P450 , Feminino , Fígado/metabolismo , Fígado/ultraestrutura , Perexilina/toxicidadeRESUMO
AIM: Little is known regarding the steady-state uptake of drugs into the human myocardium. Perhexiline is a prophylactic anti-anginal drug which is increasingly also used in the treatment of heart failure and hypertrophic cardiomyopathy. We explored the relationship between plasma perhexiline concentrations and its uptake into the myocardium. METHODS: Blood, right atrium ± left ventricle biopsies were obtained from patients treated with perhexiline for a median of 8.5 days before undergoing coronary surgery in the perhexiline arm of a randomized controlled trial. Perhexiline concentrations in plasma and heart tissue were determined by HPLC. RESULTS: Atrial biopsies were obtained from 94 patients and ventricular biopsies from 28 patients. The median plasma perhexiline concentration was within the therapeutic range at 0.24 mg l⻹ (IQR 0.12-0.44), the median atrial concentration was 6.02 mg kg⻹ (IQR 2.70-9.06) and median ventricular concentration was 10.0 mg kg⻹ (IQR 5.76-13.1). Atrial (r² = 0.76) and ventricular (r² = 0.73) perhexiline concentrations were closely and directly correlated with plasma concentrations (both P < 0.001). The median atrial : plasma ratio was 21.5 (IQR 18.1-27.1), ventricular : plasma ratio was 34.9 (IQR 24.5-55.2) and ventricular : atrial ratio was 1.67 (IQR 1.39-2.22). Using multiple regression, the best model for predicting steady-state atrial concentration included plasma perhexiline, heart rate and age (r² = 0.83). Ventricular concentrations were directly correlated with plasma perhexiline concentration and length of therapy (r² = 0.84). CONCLUSIONS: This study demonstrates that plasma perhexiline concentrations are predictive of myocardial drug concentrations, a major determinant of drug effect. However, net myocardial perhexiline uptake is significantly modulated by patient age, potentially via alteration of myocardial:extracardiac drug uptake.
Assuntos
Miocárdio/metabolismo , Perexilina/farmacocinética , Fatores Etários , Idoso , Biópsia , Método Duplo-Cego , Humanos , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
BACKGROUND: Tacrolimus (TAC) has a narrow therapeutic index and high interindividual and intraindividual pharmacokinetic variability, necessitating therapeutic drug monitoring to individualize dosage. Recent evidence suggests that intragraft TAC concentrations may better predict transplant outcomes. This study aimed to develop a method for the quantification of TAC in small biopsy-sized samples of rat kidney and liver tissue, which could be applied to clinical biopsy samples from kidney transplant recipients. METHODS: Kidneys and livers were harvested from Mrp2-deficient TR- Wistar rats administered TAC (4 mg·kg·d for 14 days, n = 8) or vehicle (n = 10). Tissue samples (0.20-1.00 mg of dry weight) were solubilized enzymatically and underwent liquid-liquid extraction before analysis by liquid chromatography tandem mass spectrometry method. TAC-free tissue was used in the calibrator and quality control samples. Analyte detection was accomplished using positive electrospray ionization (TAC: m/z 821.5 â 768.6; internal standard ascomycin m/z 809.3 â 756.4). RESULTS: Calibration curves (0.04-2.6 µg/L) were linear (R > 0.99, n = 10), with interday and intraday calibrator coefficients of variation and bias <17% at the lower limit of quantification and <15% at all other concentrations (n = 6-10). Extraction efficiencies for TAC and ascomycin were approximately 70%, and matrix effects were minimal. Rat kidney TAC concentrations were higher (range 109-190 pg/mg tissue) than those in the liver (range 22-53 pg/mg of tissue), with median tissue/blood concentrations ratios of 72.0 and 17.6, respectively. In 2 transplant patients, kidney TAC concentrations ranged from 119 to 285 pg/mg of tissue and were approximately 20 times higher than whole blood trough TAC concentrations. CONCLUSIONS: The method displayed precision and accuracy suitable for application to TAC measurement in human kidney biopsy tissue.
Assuntos
Rejeição de Enxerto/prevenção & controle , Imunossupressores/química , Imunossupressores/farmacocinética , Rim/química , Fígado/química , Tacrolimo/química , Tacrolimo/farmacocinética , Animais , Biópsia , Cromatografia Líquida/métodos , Monitoramento de Medicamentos , Rejeição de Enxerto/metabolismo , Humanos , Rim/metabolismo , Transplante de Rim , Fígado/metabolismo , Masculino , Ratos , Ratos Wistar , Espectrometria de Massas em Tandem/métodosRESUMO
Background: Dysregulated inflammation is important in the pathogenesis of many diseases including cancer, allergy, and autoimmunity. Macrophage activation and polarisation are commonly involved in the initiation, maintenance and resolution of inflammation. Perhexiline (PHX), an antianginal drug, has been suggested to modulate macrophage function, but the molecular effects of PHX on macrophages are unknown. In this study we investigated the effect of PHX treatment on macrophage activation and polarization and reveal the underlying proteomic changes induced. Methods: We used an established protocol to differentiate human THP-1 monocytes into M1 or M2 macrophages involving three distinct, sequential stages (priming, rest, and differentiation). We examined the effect of PHX treatment at each stage on the polarization into either M1 or M2 macrophages using flow cytometry, quantitative polymerase chain reaction (qPCR) and enzyme linked immunosorbent assay (ELISA). Quantitative changes in the proteome were investigated using data independent acquisition mass spectrometry (DIA MS). Results: PHX treatment promoted M1 macrophage polarization, including increased STAT1 and CCL2 expression and IL-1ß secretion. This effect occurred when PHX was added at the differentiation stage of the M1 cultures. Proteomic profiling of PHX treated M1 cultures identified changes in metabolic (fatty acid metabolism, cholesterol homeostasis and oxidative phosphorylation) and immune signalling (Receptor Tyrosine Kinase, Rho GTPase and interferon) pathways. Conclusion: This is the first study to report on the action of PHX on THP-1 macrophage polarization and the associated changes in the proteome of these cells.
Assuntos
Perexilina , Proteômica , Humanos , Perexilina/metabolismo , Perexilina/farmacologia , Proteoma/metabolismo , Macrófagos , Diferenciação Celular , Inflamação/metabolismoRESUMO
Perhexiline (Px) inhibits carnitine palmitoyltransferase 1 (CPT1), which controls uptake of long chain fatty acids into mitochondria. However, occasional cases of hypoglycaemia have been reported in Px-treated patients, raising the possibility that Px may also increase sensitivity to insulin. Furthermore, Px increases anti-aggregatory responses to nitric oxide (NO), an effect which may theoretically parallel insulin sensitization. We therefore sought to examine these relationships in patients with stable Type 2 diabetes (T2D) and cardiovascular disease (n = 30). Px was initiated, and dosage was titrated, to reach the therapeutic range and thus prevent toxicity. Investigations were performed before and after 2 weeks, to examine changes in insulin sensitivity and, utilizing aggregometry in whole blood, platelet responsiveness to the anti-aggregatory effects of the NO donor sodium nitroprusside (SNP). Other parameters that affect may affect NO signalling were also evaluated. Px substantially potentiated inhibition of platelet aggregation by SNP (from 16.7 ± 3.0 to 27.3 ± 3.7%; p = 0.005). Px did not change fasting blood glucose concentrations but reduced insulin sensitivity (HOMA-IR score increased from median of 4.47 to 6.08; p = 0.028), and increased fasting plasma insulin concentrations (median 16.5 to 19.0 mU/L; p = 0.014). Increases in SNP responses tended (r = -0.30; p = 0.11) to be reciprocally related to increases in HOMA-IR, and increases in HOMA-IR were greater (p = 0.002) in patients without NO-sensitizing effects. No patient developed symptomatic hypoglycaemia, nor was there any other short-term toxicity of Px. Thus, in patients with stable T2D and cardiovascular disease, Px increases anti-aggregatory responsiveness to NO, but is not an insulin sensitizer, and does not induce hypoglycaemia. Absence of NO-sensitizing effect occurs in approximately 30% of Px-treated patients with T2D, and is associated with induction of insulin resistance in these patients.
RESUMO
Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide. Perhexiline, a prophylactic anti-anginal drug, has been reported to have anti-tumour effects both in vitro and in vivo. Perhexiline as used clinically is a 50:50 racemic mixture ((R)-P) of (-) and (+) enantiomers. It is not known if the enantiomers differ in terms of their effects on cancer. In this study, we examined the cytotoxic capacity of perhexiline and its enantiomers ((-)-P and (+)-P) on CRC cell lines, grown as monolayers or spheroids, and patient-derived organoids. Treatment of CRC cell lines with (R)-P, (-)-P or (+)-P reduced cell viability, with IC50 values of ~4 µM. Treatment was associated with an increase in annexin V staining and caspase 3/7 activation, indicating apoptosis induction. Caspase 3/7 activation and loss of structural integrity were also observed in CRC cell lines grown as spheroids. Drug treatment at clinically relevant concentrations significantly reduced the viability of patient-derived CRC organoids. Given these in vitro findings, perhexiline, as a racemic mixture or its enantiomers, warrants further investigation as a repurposed drug for use in the management of CRC.
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Therapeutic drug monitoring is used to individualize cyclosporine A (CsA) dosing after transplantation. However, immunosuppressant concentrations within the graft may better predict clinical outcomes, including toxicity. This study aimed to develop a method suitable for CsA measurement using routine fine-needle biopsy samples. CsA was quantified retrospectively in kidney and liver tissues from 10 rats administered CsA, and 21 core needle kidney biopsies taken from renal transplant patients with suspected graft dysfunction. Dried biopsies were weighed (mean ± SD weights of 0.22 ± 0.18 mg), enzymatically solubilized, and then CsA was extracted and quantified using online 2-dimensional liquid chromatography-tandem mass spectrometry. The method was linear (r² > 0.997, n = 10), accurate, and precise (quality control and calibrator coefficient of variation and bias <15%), with minimal matrix effects (coefficient of variation and bias <15%). Reproducibility of tissue weight measurements was confirmed by retrospective DNA quantitation, with a significant linear correlation between weight and total DNA concentration (r² = 0.988). In rats, there was a significant linear correlation between CsA concentrations in liver and kidney tissues (r² = 0.996) but there was no correlation between blood (C0) and tissue CsA concentrations (Spearman r = 0.430 and 0.503, P > 0.05). Similarly, in 16 transplant patients, for whom blood CsA concentrations (C2) were available within 1 day of the renal biopsy being performed, there was no significant correlation between CsA concentrations in blood and kidney tissue (Spearman r = 0.168, P > 0.05). In situ CsA measurements acquired using this method could make an easy transition into clinical use due to their retrospective nature and minimal disruption to current clinical protocols and could provide an additional tool for optimizing clinical outcomes in the future.
Assuntos
Inibidores de Calcineurina , Ciclosporina/farmacocinética , Inibidores Enzimáticos/farmacocinética , Rejeição de Enxerto/prevenção & controle , Imunossupressores/farmacocinética , Transplante de Rim/efeitos adversos , Rim/química , Adolescente , Adulto , Idoso , Animais , Biópsia por Agulha Fina , Ciclosporina/análise , Ciclosporina/sangue , Ciclosporina/uso terapêutico , Monitoramento de Medicamentos , Inibidores Enzimáticos/análise , Inibidores Enzimáticos/sangue , Inibidores Enzimáticos/uso terapêutico , Feminino , Humanos , Imunossupressores/análise , Imunossupressores/sangue , Imunossupressores/uso terapêutico , Rim/patologia , Transplante de Rim/patologia , Fígado/química , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Ratos , Ratos Wistar , Reprodutibilidade dos Testes , Estudos Retrospectivos , Distribuição Tecidual , Adulto JovemRESUMO
MATERIALS AND METHODS: Two hundred patients at steady-state on long-term perhexiline were identified retrospectively. The ratio of maintenance dose to steady-state plasma concentration (dose:[Px]) was correlated with the following putative determinants via simple and multiple linear regression analyses: age, weight, left ventricular ejection fraction (LVEF), and creatinine clearance (CrCl, Cockroft-Gault formula). A Mann-Whitney U test was performed to determine if severe left ventricular systolic impairment affected maintenance dose. RESULTS: Advanced age, left ventricular systolic impairment, and renal impairment were frequently encountered. Using simple linear regression, age was a negative correlate of dose:[P] (R = 0.23, P = 0.001), whereas weight (R = 0.27, P = 0.0001) and CrCl (R = 0.30, P < 0.0001) were positive correlates. Mann-Whitney U analysis showed no difference between dose: [Px] among patients with LVEF of less than 30% versus 30% or greater. Advancing age was strongly associated with decreasing weight (R = -0.45, P < 0.00001) and calculated CrCl varied directly with weight, as expected (R = 0.66, P < 0.0001). Stepwise multiple linear regression using age, LVEF, CrCl, and weight as potential predictors of dose:[P] yielded only weight as a significant determinant. DISCUSSION: Perhexiline has become a "last-line" agent for refractory angina as a result of complex pharmacokinetics and potential toxicity. Use has increased predictably in the aged and infirm who have exhausted standard medical and surgical therapeutic options. Beyond genotype, the effect of patient characteristics on maintenance dose has not been explored in detail. In this study, dose requirement declined with age in a frail and wasting population as a result of weight-related pharmacokinetic factors. LVEF had no apparent effect on maintenance dose and should not be considered a contraindication to use. CONCLUSION: A weight-adjusted starting dose may facilitate the safe and effective prescription of perhexiline and is calculated by 50 + 2 × weight (kg) mg/d, rounded to the closest 50 mg/day.
Assuntos
Envelhecimento , Angina Pectoris/tratamento farmacológico , Fármacos Cardiovasculares/farmacocinética , Perexilina/farmacocinética , Insuficiência Renal/metabolismo , Disfunção Ventricular Esquerda , Idoso , Idoso de 80 Anos ou mais , Angina Pectoris/fisiopatologia , Peso Corporal/fisiologia , Fármacos Cardiovasculares/efeitos adversos , Fármacos Cardiovasculares/sangue , Fármacos Cardiovasculares/uso terapêutico , Creatinina/metabolismo , Humanos , Pessoa de Meia-Idade , Perexilina/efeitos adversos , Perexilina/sangue , Perexilina/uso terapêutico , Estudos RetrospectivosRESUMO
Tacrolimus is an essential immunosuppressant for the prevention of rejection in solid organ transplantation. Its low therapeutic index and high pharmacokinetic variability necessitates therapeutic drug monitoring (TDM) to individualise dose. However, rejection and toxicity still occur in transplant recipients with blood tacrolimus trough concentrations (C0) within the target ranges. Peripheral blood mononuclear cells (PBMC) have been investigated as surrogates for tacrolimus's site of action (lymphocytes) and measuring allograft tacrolimus concentrations has also been explored for predicting rejection or nephrotoxicity. There are relatively weak correlations between blood and PBMC or graft tacrolimus concentrations. Haematocrit is the only consistent significant (albeit weak) determinant of tacrolimus distribution between blood and PBMC in both liver and renal transplant recipients. In contrast, the role of ABCB1 pharmacogenetics is contradictory. With respect to distribution into allograft tissue, studies report no, or poor, correlations between blood and graft tacrolimus concentrations. Two studies observed no effect of donor ABCB1 or CYP3A5 pharmacogenetics on the relationship between blood and renal graft tacrolimus concentrations and only one group has reported an association between donor ABCB1 polymorphisms and hepatic graft tacrolimus concentrations. Several studies describe significant correlations between in vivo PBMC tacrolimus concentrations and ex vivo T-cell activation or calcineurin activity. Older studies provide evidence of a strong predictive value of PBMC C0 and allograft tacrolimus C0 (but not blood C0) with respect to rejection in liver transplant recipients administered tacrolimus with/without a steroid. However, these results have not been independently replicated in liver or other transplants using current triple maintenance immunosuppression. Only one study has reported a possible association between renal graft tacrolimus concentrations and acute tacrolimus nephrotoxicity. Thus, well-designed and powered prospective clinical studies are still required to determine whether measuring tacrolimus PBMC or graft concentrations offers a significant benefit compared to current TDM.
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BACKGROUND: Innate immunity contributes to acute rejection after kidney transplantation. Genetic polymorphisms affecting innate immunity may therefore influence patients' risk of rejection. IL2 -330T > G, IL10 -1082G > A, -819C > T, and -592C > A, and TNF -308G > A are not associated with acute rejection incidence in Caucasian kidney transplant recipients receiving a calcineurin inhibitor, ciclosporin or tacrolimus (TAC). However, other important innate immune genetic polymorphisms have not yet been extensively studied in recipients and donors. In addition, innate immunogenetics have not been investigated in kidney transplant cohorts receiving only TAC as the calcineurin inhibitor. OBJECTIVE: To investigate the effect of recipient and donor CASP1, CRP, IL1B, IL2, IL6, IL6R, IL10, MYD88, TGFB, TLR2, TLR4, and TNF genetics on acute kidney rejection in the first 2 weeks post-transplant in TAC-treated kidney transplant recipients. METHODS: This study included 154 kidney transplant recipients and 81 donors successfully genotyped for 17 polymorphisms in these genes. All recipients were under triple immunosuppressant therapy of TAC, mycophenolate mofetil, and prednisolone. Recipient and donor genotype differences in acute rejection incidence within the first 2 weeks post-transplantation were assessed by logistic regression, adjusting for induction therapy, human leukocyte antigen mismatches, kidney transplant number, living donor, and peak panel-reactive antibody scores. RESULTS: A trend (Cochran-Armitage P = 0.031) of increasing acute rejection incidence was observed from recipient IL6 -6331 T/T (18%) to T/C (25%) to C/C (46%) genotype [C/C versus T/T odds ratio (95% confidence interval) = 6.6 (1.7 to 25.8) (point-wise P = 0.017)]. However, no genotype differences were significant after Bonferroni correction for multiple comparisons. CONCLUSIONS: This study did not detect any statistically significant effects of recipient or donor innate immune genetics on acute rejection incidence in the first 2 weeks post-transplantation. However, the sample size was small, and future larger studies or meta-analyses are required to demonstrate conclusively if innate immune genetics such as IL6 influence the risk of acute rejection after kidney transplantation.