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1.
Transpl Infect Dis ; 20(5): e12934, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29809312

RESUMO

INTRODUCTION: Although antiviral prophylaxis is effective in preventing early cytomegalovirus (CMV) reactivation following liver transplantation (OLT), it predisposes patients to late CMV after prophylaxis has ceased. QuantiFERON-CMV (QFN-CMV, Qiagen, The Netherlands) measures an individual's viral-specific immune response. METHODS: Fifty-nine OLT recipients were prospectively monitored post-OLT in an observational cohort study. QFN-CMV was performed at regular time-points. An absolute QFN-CMV <0.1 IU/mL was considered non-reactive. RESULTS: 50/59 (84.7%) had a reactive QFN-CMV by M6. 38/59 (64.4%) had antiviral prophylaxis or treatment before M6, with 31/38 (81.6%) developing a reactive QFN-CMV by 6 months. Over 90% already had a reactive result as early as 3 months post transplant, 3 patients (5.08%) developed late CMV between 6-12 months (median 251 days)-all had a non-reactive M6 QFN-CMV. And 2/3 experienced CMV disease. Non-reactive M6 QFN-CMV was significantly associated with late CMV (OR = 54.4, PPV = 0.33, NPV = 1.00, P = .003). CONCLUSION: Although only 5% of recipients developed late CMV, 2/3 suffered CMV disease. M6 QFN-CMV has an excellent NPV for late CMV, suggesting patients who exhibit a robust ex vivo immune response at M6 can safely cease CMV monitoring. Furthermore, >90% already express viral-specific immunity as early as 3 months. Conceivably, antiviral prophylaxis could be discontinued early in these patients.


Assuntos
Infecções por Citomegalovirus/sangue , Citomegalovirus/fisiologia , Transplante de Fígado/efeitos adversos , Linfócitos T/imunologia , Ativação Viral , Antibioticoprofilaxia/métodos , Antivirais/uso terapêutico , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Testes Sorológicos/instrumentação , Testes Sorológicos/métodos , Resultado do Tratamento , Carga Viral/imunologia
2.
J Viral Hepat ; 23(9): 730-43, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27167351

RESUMO

In recurrent hepatitis C (HCV) post-liver transplantation (OLT), the combination of immunosuppressants and HCV is postulated to increase hepatocyte apoptosis and liver fibrosis. We evaluated hepatocyte apoptosis within the liver tissue of patients with postOLT HCV recurrence compared to HCV-negative individuals and correlated these findings with the effects of immunosuppressants on HCV-induced cell death and its inhibition in primary mouse hepatocytes (PMoH). Liver biopsies from patients with and without HCV were evaluated by immunohistochemistry for markers of apoptosis M30 CytoDEATH (M30) and cleaved PARP (clPARP). PMoH from C57BL/6 mice were infected with recombinant adenoviruses (rAdHCV) that expressed HCV proteins in hepatocytes. Infected cells were treated with cyclosporine, tacrolimus, sirolimus and/or MMF with or without pan-caspase inhibitor Q-VD-Oph. Cell viability and apoptosis were evaluated using crystal violet assays and Western immunoblots probed for cleaved caspase-3 (clCas3) and clPARP. Both M30 and clPARP were increased in the liver biopsies of patients with postOLT HCV recurrence compared to HCV-negative individuals. Treatment of rAdHCV-infected PMoH with cyclosporine, tacrolimus or sirolimus reduced cell viability and increased clCas3 and clPARP compared to rAdHCV infection alone. Addition of MMF to cyclosporine, tacrolimus or sirolimus further reduced cell viability and increased clCas3 and clPARP. Q-VD-Oph improved cell viability in HCV-infected PMoH treated with immunosuppressants alone and in combination and reduced clCas3 and clPARP by approximately 90%. Immunosuppressive agents, especially in combination, enhanced apoptosis in HCV-infected hepatocytes. The finding that Q-VD-Oph reversed hepatocyte death suggests that treatments utilizing apoptosis inhibition might reduce liver injury in postOLT HCV recurrence.


Assuntos
Apoptose , Hepatite C/patologia , Hepatócitos/fisiologia , Hepatócitos/virologia , Imunossupressores/uso terapêutico , Transplante de Fígado , Animais , Biópsia , Sobrevivência Celular , Células Cultivadas , Humanos , Imuno-Histoquímica , Fígado/patologia , Camundongos Endogâmicos C57BL
3.
Am J Transplant ; 15(2): 555-9, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25582147

RESUMO

Unexpected donor-to-recipient infectious disease transmission is an important, albeit rare, complication of solid organ transplantation. Greater work and understanding about the epidemiology of these donor-derived transmissions is continually required to further mitigate this risk. Herein we present the first reported case of proven donor-derived transmission of coxsackievirus serogroup-3, an enterovirus, following solid organ transplant. Swift and effective communication between the organ donation agency, treating physicians, laboratory testing and notification ensured a coordinated approach. The resulting clinical syndromes in the organ recipients were mild. This case highlights the requirement for ongoing surveillance over a broad range of infecting pathogens that may present as a donor-derived infection.


Assuntos
Infecções por Coxsackievirus/transmissão , Enterovirus Humano B/patogenicidade , Transplante de Rim , Transplante de Fígado , Transplante de Pulmão , Transplante de Pâncreas , Doadores de Tecidos , Adulto , Biópsia , Enterovirus Humano B/isolamento & purificação , Humanos , Rim/patologia , Rim/virologia , Fígado/patologia , Fígado/virologia , Pulmão/patologia , Pulmão/virologia , Pâncreas/patologia , Pâncreas/virologia , Transplantados
4.
Intern Med J ; 44(6): 601-4, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24946816

RESUMO

Homozygous familial hypercholesterolaemia (FH) causes severe premature coronary artery disease because of very high levels of low density lipoprotein (LDL)-cholesterol. Standard lipid-lowering drugs and LDL-apheresis may not be sufficiently effective. Liver transplantation replaces defective LDL receptors and vastly improves the lipid profile, and we present the first report of an Australian adult to receive this treatment. Emerging drug treatments for FH may be alternatives to LDL-apheresis and transplantation, but long-term safety and efficacy data are lacking for all of these options.


Assuntos
Hiperlipoproteinemia Tipo II/tratamento farmacológico , Hiperlipoproteinemia Tipo II/cirurgia , Hipolipemiantes/uso terapêutico , Transplante de Fígado , Adulto , Atorvastatina , Azetidinas/administração & dosagem , Azetidinas/uso terapêutico , Remoção de Componentes Sanguíneos , LDL-Colesterol/sangue , Terapia Combinada , Consanguinidade , Ponte de Artéria Coronária , Doença das Coronárias/genética , Doença das Coronárias/cirurgia , Quimioterapia Combinada , Ezetimiba , Fenofibrato/administração & dosagem , Fenofibrato/uso terapêutico , Doenças das Valvas Cardíacas/genética , Doenças das Valvas Cardíacas/cirurgia , Implante de Prótese de Valva Cardíaca , Ácidos Heptanoicos/administração & dosagem , Ácidos Heptanoicos/uso terapêutico , Homozigoto , Humanos , Hiperlipoproteinemia Tipo II/sangue , Hiperlipoproteinemia Tipo II/dietoterapia , Hiperlipoproteinemia Tipo II/terapia , Hipolipemiantes/administração & dosagem , Lipoproteínas LDL/sangue , Masculino , Pirróis/administração & dosagem , Pirróis/uso terapêutico , Receptores de LDL/deficiência , Receptores de LDL/genética
5.
Am J Transplant ; 13(11): 3031-4, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24007548

RESUMO

We describe the first case of a patient undergoing orthoptic liver transplantation for acquired generalized lipodystrophy-related nonalcoholic steatohepatitis who developed severe recurrence of nonalcoholic fatty liver disease in the first few months posttransplant but responded rapidly to the administration of exogenous leptin. The beneficial effects of therapy were supported by histology along with magnetic resonance spectroscopy studies, which demonstrated that leptin therapy greatly reduced fat deposition in the liver. Leptin therapy may have a role to play in preventing patients with lipodystrophy developing end-stage liver disease or in rescuing such patients who develop disease recurrence postliver transplantation.


Assuntos
Fígado Gorduroso/complicações , Leptina/farmacologia , Lipodistrofia/complicações , Transplante de Fígado/efeitos adversos , Complicações Pós-Operatórias/prevenção & controle , Prevenção Secundária , Adulto , Fígado Gorduroso/patologia , Fígado Gorduroso/cirurgia , Feminino , Humanos , Lipodistrofia/patologia , Lipodistrofia/cirurgia , Espectroscopia de Ressonância Magnética , Hepatopatia Gordurosa não Alcoólica , Resultado do Tratamento
6.
Gut ; 60(2): 247-54, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21036792

RESUMO

OBJECTIVE: To determine the efficacy of tenofovir disoproxil fumarate (TDF) in adults with chronic hepatitis B virus (HBV) infection who had previously failed lamivudine (LAM) and had significant viral replication (HBV DNA >105 copies/ml if HBeAg positive, > 104 copies/ml if HBeAg negative) despite at least 24 weeks of treatment with adefovir dipivoxil (ADV). DESIGN: A prospective open-label study of TDF 300 mg daily. Patients receiving combination ADV/LAM prior to baseline were switched to TDF/LAM. SETTING: Multiple tertiary referral centres. METHODS: Sixty patients were enrolled. The median age was 48.5 years (range 21e80), 46 (77%) were male and 40 (67%) were HBeAg positive. Thirty-eight patients (63%) were switched from ADV to TDF, the remainder from ADV/LAM to TDF/LAM. At baseline, substitutions conferring resistance to LAM or ADV were present in 20 patients (33%) and 17 patients (28%), respectively. The median baseline viral load was 5.33 log10 IU/ml (range 2.81-8.04). Patients initially treated with TDF monotherapy with persistent viral replication at or after 24 weeks were switched to TDF/LAM. The main outcome measures were change in HBV viral load from baseline and percentage of patients achieving an undetectable viral load (<15 IU/ml). RESULTS: Results are reported at 96 weeks of treatment. One patient discontinued TDF at 10 days due to rash. The time-weighted change in viral load from baseline to week 12 was -2.19 log10 IU/ml overall. The median change in HBV DNA from baseline to weeks 12, 24, 48 and 96 was -2.86, -3.23, -3.75 and -4.03 log10 IU/ml, respectively. At 48 and 96 weeks, 27/59 (46%) and 38/59 (64%) patients achieved a HBV DNA <15 IU/ml. The response was independent of baseline LAM therapy or mutations conferring ADV resistance. CONCLUSIONS: In heavily pretreated patients with a high rate of genotypic resistance, TDF retains significant activity against HBV although this appears diminished in comparison with studies of naïve patients.


Assuntos
Adenina/análogos & derivados , Hepatite B Crônica/tratamento farmacológico , Organofosfonatos/uso terapêutico , Inibidores da Transcriptase Reversa/uso terapêutico , Terapia de Salvação/métodos , Adenina/efeitos adversos , Adenina/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , DNA Viral/sangue , Farmacorresistência Viral/genética , Métodos Epidemiológicos , Feminino , Vírus da Hepatite B/efeitos dos fármacos , Vírus da Hepatite B/genética , Vírus da Hepatite B/isolamento & purificação , Hepatite B Crônica/virologia , Humanos , Lamivudina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Mutação , Organofosfonatos/efeitos adversos , Inibidores da Transcriptase Reversa/efeitos adversos , Tenofovir , Falha de Tratamento , Resultado do Tratamento , Carga Viral , Adulto Jovem
7.
Am J Transplant ; 11(1): 169-72, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21199357

RESUMO

Multicentric Castleman disease is a lymphoproliferative disorder which when seen in the setting of HIV/AIDS is often associated with human herpes virus 8 (HHV-8) infection. We describe the case of a HIV-negative man who developed HHV-8-associated multicentric Castleman disease 11 years after liver transplantation. The patient presented with fevers and weight loss. Physical examination revealed enlarged cervical, axillary and inguinal lymph nodes. Widespread lymphadenopathy was confirmed on computed tomography (CT) scanning. Histology of an enlarged lymph node showed a polymorphous infiltrate with mature plasma cells, plasmacytoid lymphocytes and occasional blasts within the cortex and paracortex. The diagnosis of Castleman disease was confirmed by the finding of numerous HHV-8-immunopositive cells around the regressed lymph node follicles and the detection of HHV-8 on plasma PCR. Although the conventional treatment for this condition has been combination chemotherapy, in the post-transplant context it was decided to treat the patient with valganciclovir and cessation of immunosuppression. His symptoms resolved rapidly and repeat plasma PCR done 3 months after starting treatment was negative for HHV-8. A follow-up CT scan showed a dramatic reduction in the size and amount of lymphadenopathy. After 15 months of treatment, he remains well with no evidence of graft dysfunction or rejection.


Assuntos
Ganciclovir/análogos & derivados , Hiperplasia do Linfonodo Gigante/tratamento farmacológico , Hiperplasia do Linfonodo Gigante/etiologia , Hiperplasia do Linfonodo Gigante/patologia , Ganciclovir/uso terapêutico , Humanos , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Valganciclovir
8.
Aliment Pharmacol Ther ; 47(3): 401-411, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29205432

RESUMO

BACKGROUND: Antiviral therapy for hepatitis C has the potential to improve liver function in patients with decompensated cirrhosis. AIMS: To examine the virological response and effect of viral clearance in patients with decompensated hepatitis C cirrhosis all with MELD scores ≥15 following sofosbuvir/daclatasvir ± ribavirin. METHODS: We prospectively collected data on patients who commenced sofosbuvir/daclatasvir for 24-weeks under the Australian patient supply program (TOSCAR) and analysed outcomes including sustained viral response at 12 weeks (SVR12), death and transplant. RESULTS: 108 patients (M/F, 79/29; median age 56years; Child-Pugh 10; MELD 16; genotype 1/3, 55/47) received sofosbuvir/daclatasvir and two also received ribavirin. On intention-to-treat, the SVR12 rate was 70% (76/108). Seventy-eight patients completed 24-weeks therapy. SVR12 was achieved in 56 of these patients on per-protocol-analysis (76%). SVR12 was 80% in genotype 1 compared to 69% in genotype 3. Thirty patients failed to complete therapy. In patients achieving SVR12, median MELD and Child-Pugh fell from 16(IQR15-17) to 14(12-17) and 10(9-11) to 8(7-9), respectively (P<.001). In those who died, MELD increased from 16 to 23 at death (P=.036). Patients who required transplantation had a significantly higher baseline MELD (20) compared to those patients completing treatment (16) (P=.0010). The odds ratio for transplant in patients with baseline MELD ≥20 was 13.8(95%CI 2.78-69.04). CONCLUSIONS: SVR12 rates with sofosbuvir/daclatasvir in advanced liver disease are lower than in compensated disease. Although treatment improves MELD and Child-Pugh in most patients, a significant proportion will die or require transplantation. In those with MELD ≥20, it may be better to delay treatment until post-transplant.


Assuntos
Antivirais/administração & dosagem , Hepatite C Crônica/tratamento farmacológico , Imidazóis/administração & dosagem , Cirrose Hepática/tratamento farmacológico , Sofosbuvir/administração & dosagem , Austrália/epidemiologia , Carbamatos , Ensaios de Uso Compassivo , Progressão da Doença , Quimioterapia Combinada , Feminino , Hepatite C Crônica/complicações , Hepatite C Crônica/epidemiologia , Hepatite C Crônica/patologia , Humanos , Cirrose Hepática/epidemiologia , Cirrose Hepática/patologia , Cirrose Hepática/virologia , Transplante de Fígado/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Pirrolidinas , Estudos Retrospectivos , Ribavirina/administração & dosagem , Análise de Sobrevida , Resultado do Tratamento , Valina/análogos & derivados
9.
Intern Med J ; 37(10): 705-12, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17894766

RESUMO

It is well known that immunosuppressive drugs or cancer chemotherapy can stimulate replication of hepatitis B virus (HBV) and precipitate severe flares of HBV infection. The risk of this syndrome of 'reactivation hepatitis B' is highest in haematopoietic stem cell or solid organ transplant recipients and in those undergoing chemotherapy for haematological malignancies; however, it has been described following almost any form of immunosuppressive treatment. Fortunately, it can be largely prevented by prophylactic therapy with oral anti-HBV nucleoside/nucleotide analogues. Importantly, chronic HBV infection is usually asymptomatic, and most patients at risk are likely to be unaware that they carry the infection. Thus, the key to avoiding this potentially fatal complication of immunosuppressive treatment is to ensure that all patients at risk of chronic HBV infection are screened for the disease before commencing immunosuppressive treatment or chemotherapy.


Assuntos
Vírus da Hepatite B/fisiologia , Hepatite B/prevenção & controle , Hepatite B/terapia , Imunossupressores/efeitos adversos , Guias de Prática Clínica como Assunto , Ativação Viral/efeitos dos fármacos , Animais , Gerenciamento Clínico , Hepatite B/imunologia , Humanos , Guias de Prática Clínica como Assunto/normas , Ativação Viral/fisiologia
12.
Aliment Pharmacol Ther ; 43(7): 765-77, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26847265

RESUMO

BACKGROUND: Sarcopenia (loss of muscle mass) is common in cirrhosis and is associated with poor outcomes. Current teaching recommends the use of protein supplementation and exercise, however, this fails to address many other factors which contribute to muscle loss in this setting. AIMS: To summarise existing knowledge regarding the aetiology of sarcopenia in cirrhosis, diagnostic modalities and the clinical significance of this condition. In addition to discuss recent research findings that may allow the development of more effective treatments. METHODS: We conducted a Medline and PubMed search using the search terms 'sarcopenia', 'muscle', 'body composition', 'cirrhosis', 'liver' and 'malnutrition' from inception to October 2015. RESULTS: Cirrhotic patients with sarcopenia have reduced survival, experience increased rates of infection and have worse outcomes following liver transplantation. The aetiology of this condition is more complex than simple protein and calorie malnutrition. Cirrhosis also results in depleted glycogen stores and metabolic alterations that cause excessive protein catabolism, increased activation of the ubiquitin-proteasome pathway and inappropriate muscle autophagy. Satellite cell differentiation and proliferation is also reduced due to a combination of elevated myostatin levels, reduced IGF-1 and hypogonadism. Although there is some evidence supporting the use of late evening snacks, branched chain amino acid supplementation and high protein/high calorie diets, well designed clinical trials addressing the effects of treatment on body composition in cirrhosis are lacking. CONCLUSION: Sarcopenia in cirrhosis has a complex pathogenesis and simple dietary interventions are insufficient. Improved understanding of the multiple mechanisms involved should allow the development of more effective therapies, which target the specific underlying metabolic derangements.


Assuntos
Cirrose Hepática/complicações , Cirrose Hepática/diagnóstico , Sarcopenia/diagnóstico , Sarcopenia/etiologia , Adulto , Composição Corporal , Feminino , Humanos , Cirrose Hepática/terapia , Transplante de Fígado/efeitos adversos , Transplante de Fígado/tendências , Síndromes de Malabsorção/complicações , Síndromes de Malabsorção/diagnóstico , Síndromes de Malabsorção/terapia , Pessoa de Meia-Idade , Proteólise , Sarcopenia/terapia , Resultado do Tratamento
13.
Biochem Pharmacol ; 37(7): 1207-12, 1988 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-3355595

RESUMO

In isolated hepatocytes the availability of intracellular glucose appears to be a key factor controlling the rate of xenobiotic glucuronidation during hypoxia. This study in the isolated perfused rat liver examines the effect of both a 24-hr fast and removal of glucose (8 mM) from liver perfusate on the elimination of bolus doses of harmol (20 mumol) under normoxic and hypoxic conditions. In the preparations used in these experiments, harmol glucuronide is the major metabolite (greater than 80%) with the remainder being sulphate. During normal oxygenation, in the livers from fed rats, harmol was rapidly eliminated (t1/2 = 4.2 +/- 0.4 min; mean +/- SD, N = 4). Fasting led to a small reduction in harmol elimination rate (t1/2 = 5.6 +/- 0.4 min; P less than 0.025) while removal of glucose from perfusate made no difference in either fed or fasted preparations. In the same livers, a second bolus dose of harmol was given during hypoxia. This produced a modest decline in harmol elimination in fed rats (t1/2 = 7.1 +/- 2.0 min; P less than 0.05). However, in fasted rats there was a striking reduction in harmol elimination (t1/2 = 109.8 +/- 54.0 min; P less than 0.025). The removal of glucose from perfusate made no significant difference to these results (t1/2 = 253 +/- 209 min in fasted preparations, P greater than 0.1). In all preparations, reoxygenation resulted in a rapid recovery of drug elimination. We conclude that nutritional state is important in determining the impact of hypoxia on harmol elimination by the liver. This study suggests that clinically significant reductions in xenobiotic glucuronidation are most likely to occur in poorly nourished or fasted subjects who became hypoxaemic.


Assuntos
Alcaloides/metabolismo , Jejum , Harmina/metabolismo , Hipóxia/metabolismo , Fígado/metabolismo , Animais , Glucose/farmacologia , Harmina/análogos & derivados , Técnicas In Vitro , Lactatos/análise , Ácido Láctico , Masculino , Consumo de Oxigênio , Perfusão , Piruvatos/análise , Ácido Pirúvico , Ratos , Ratos Endogâmicos , Uridina Difosfato Ácido Glucurônico/metabolismo
14.
Biochem Pharmacol ; 45(3): 763-5, 1993 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-8442773

RESUMO

The effect of hypoxia and acidosis on the elimination of an oxidatively metabolized drug, S-propranolol, was examined in the single-pass isolated perfused rat liver (IPRL). The experiments (N = 6) consisted of four consecutive 30 min phases: normal pH (pH 7.4)/normal oxygen delivery, normal pH/hypoxia, hypercapnic acidosis (pH 7.1)/normal oxygenation and hypercapnic acidosis/hypoxia. Hypoxia and acidosis were produced by equilibrating the perfusate with appropriate mixtures of O2, N2 and CO2. With normal oxygen delivery there was no difference in hepatic clearance of propranolol between normal pH and acidosis (9.65 +/- 0.34 and 9.78 +/- 0.11 mL/min, respectively. P < 0.05). During hypoxia, propranolol clearance was impaired to a similar extent under both pH conditions (7.41 +/- 0.97 and 8.06 +/- 0.81 mL/min, respectively, P > 0.05). Therefore, respiratory acidosis does not affect the clearance of propranolol by the IPRL, nor does it influence the sensitivity of propranolol clearance to hypoxia. Neither acidosis nor hypoxia resulted in a significant reduction in bile flow compared with the normal pH/normal oxygen phase and there was no correlation between bile flow and perfusate bicarbonate concentration (P > 0.05).


Assuntos
Acidose Respiratória/fisiopatologia , Hipóxia/fisiopatologia , Fígado/fisiopatologia , Propranolol/farmacocinética , Acidose Respiratória/complicações , Animais , Dióxido de Carbono , Concentração de Íons de Hidrogênio , Hipóxia/complicações , Masculino , Consumo de Oxigênio , Perfusão , Ratos , Ratos Sprague-Dawley
15.
Biochem Pharmacol ; 38(9): 1443-9, 1989 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-2719719

RESUMO

Although impairment of drug metabolism by severe hypoxia is well documented in perfused liver preparations, the degree of hypoxia required to produce inhibition of drug elimination pathways in the intact liver has not been defined. In this study, in the isolated perfused rat liver, we examined the relationship between the rate of hepatic oxygen supply and the elimination rate of the drug salbutamol, which in the rat liver is eliminated largely by glucuronidation. Livers (N = 15) from male Sprague-Dawley rats were perfused in a non-recycling design with 10% human red cells in a Krebs-Henseleit electrolyte solution. Salbutamol elimination was examined during normal oxygenation (perfusate equilibrated with 100% O2; mean O2 delivery 3.21 mumol/min/g liver), at a given lower rate of oxygen delivery (achieved by producing different mixtures of N2 with O2 in the perfusate oxygenator) and after reoxygenation. In these experiments, hepatic clearance of salbutamol (perfusate concentration 50 ng/ml) was essentially independent of oxygen delivery above a rate of 2.0 mumol/min/g liver; below this level, clearance fell linearly as O2 supply was reduced. In all livers, reoxygenation restored drug elimination to control levels. In further experiments using a recycling design (N = 22), the effect of hypoxia on salbutamol elimination was found to be very similar. In recycling normoxic experiments (N = 3), the glucuronide metabolite was detected in perfusate and bile, but no sulphate metabolite was detected. While previous studies indicate that elimination of some oxidatively metabolised substrates is very sensitive to reductions in hepatic oxygenation, the present study shows that, in the isolated liver, large reductions in hepatic oxygen supply were required to produce significant impairment of the glucuronidation-dependent elimination of salbutamol.


Assuntos
Albuterol/farmacocinética , Fígado/metabolismo , Oxigênio/farmacologia , Animais , Glucuronatos/metabolismo , Meia-Vida , Técnicas In Vitro , Masculino , Taxa de Depuração Metabólica , Consumo de Oxigênio , Perfusão , Ratos , Ratos Endogâmicos
16.
Biochem Pharmacol ; 45(3): 573-8, 1993 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-8442756

RESUMO

We investigated, using the single-pass isolated perfused rat liver preparation, whether the centrilobular location of hepatic oxidative drug metabolism could be a contributing factor to the marked sensitivity of drug oxidation to hypoxia. Livers (N = 7) were each perfused for 130 min with 2 micrograms/mL (+)-propranolol, a drug metabolized almost entirely by oxidation in the rat. The direction of flow was reversed after 60 min, the order of flow direction being randomized. Normal oxygenation was used during the first 30 min of antegrade and of retrograde perfusion, but in the second 30 min perfusate was equilibrated with a N2/O2 mixture designed to reduce hepatic oxygen delivery by half. During normal oxygenation there was no significant difference between antegrade and retrograde perfusion in hepatic oxygen delivery and physiological parameters such as oxygen consumption and extraction, perfusion pressure and bile flow. During hypoxia, mean oxygen delivery was slightly lower with retrograde perfusion (retrograde: mean = 2.37 mumol/min/g liver, range = 1.56-3.17; antegrade: mean = 2.90 mumol/min/g liver, range = 1.96-4.08; P = 0.04), but there was no significant difference in physiological parameters within each liver (P > 0.05). Propranolol clearance during normal oxygenation was similar to the perfusion rate (10 mL/min) and was the same for both directions of perfusion (antegrade 9.88 +/- 0.07 mL/min, retrograde 9.88 +/- 0.13 mL/min, P > 0.05). Hypoxia reduced propranolol clearance substantially, but the decrease was significantly greater with antegrade perfusion (5.65 +/- 1.89 mL/min) than with retrograde perfusion (6.76 +/- 1.95 mL/min, P = 0.014). Oxidative drug metabolism is located primarily in the centrilobular zone and sinusoidal oxygen concentration is lowest in the "downstream" zone with both antegrade and retrograde perfusion. These findings suggest that the centrilobular location of propranolol metabolism may influence the effect of hypoxia on propranolol elimination, but is not a major contributor to the marked sensitivity of propranolol elimination to hypoxia antegrade perfusion.


Assuntos
Fígado/metabolismo , Oxigênio/metabolismo , Propranolol/farmacocinética , Animais , Hipóxia/metabolismo , Masculino , Oxigênio/farmacologia , Consumo de Oxigênio , Perfusão , Ratos , Ratos Sprague-Dawley
17.
Aliment Pharmacol Ther ; 4(3): 213-25, 1990 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2104086

RESUMO

Most major pathways of hepatic drug metabolism are dependent on oxygen. Hepatic mixed-function oxidases use oxygen directly as a substrate, while many other enzyme systems are indirectly dependent on oxygen for the generation of essential co-factors, such as NAD+ and ATP. Studies in vitro show that many of these oxygen-dependent reactions are impaired by relatively minor reductions in oxygen supply, of a magnitude likely to be encountered in vivo. Phase I metabolism by mixed-function oxidases appears to be more sensitive to hypoxia than phase II drug conjugation, although the oxygen requirements of conjugation reactions, such as glucuronidation, may be greatly enhanced by poor nutrition or fasting. Studies in humans are few, but in general they affirm the potential importance of the effects of hypoxaemic states on hepatic drug elimination. On present evidence, special care should be taken in hypoxic patients with drugs extensively metabolized by the liver, particularly those which have a low therapeutic ratio.


Assuntos
Hipóxia/metabolismo , Fígado/metabolismo , Preparações Farmacêuticas/metabolismo , Animais , Humanos
18.
Bone Marrow Transplant ; 31(8): 701-3, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12728924

RESUMO

A small number of case reports of steatorrhoea after allogenic BMT have been published, but the incidence and natural history of this complication have not been defined. We reviewed the incidence of steatorrhoea in 184 consecutive allograft recipients surviving at least 100 days. Steatorrhoea was documented in five patients, a median of 5.5 months (range 4-14) post-transplant. All patients had recent or concomitant acute gut or liver graft versus host disease (GVHD). The probability of developing steatorrhoea by 2 years post-transplant was 3.3% (95% confidence interval (CI) +/- 2.9% in the group overall, rising to 4.8% (CI +/- 4.2%) in patients with acute and/or extensive chronic GVHD. All patients responded clinically to pancreatic enzyme supplements. While these observations are consistent with previously reported autopsy data suggesting that GVHD of the exocrine pancreas is likely to be predominant underlying pathological process, in two patients concomitant small bowel or hepatic dysfunction may have contributed to the severity of steatorrhoea. Enzyme supplements were subsequently ceased in three patients without return of steatorrhoea, suggesting that the process is usually reversible. Our data demonstrate that steatorrhoea is not infrequent complication in the 2 years postallograft, particularly in patients with GVHD.


Assuntos
Transplante de Medula Óssea/efeitos adversos , Doença Celíaca/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Adulto , Doença Celíaca/fisiopatologia , Feminino , Humanos , Incidência , Síndromes de Malabsorção/etiologia , Síndromes de Malabsorção/fisiopatologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/fisiopatologia , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo , Transplante Homólogo
19.
Bone Marrow Transplant ; 29(11): 931-3, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12080360

RESUMO

Bone marrow transplantation is potentially curative therapy for the hematologic complications associated with Shwachman-Diamond syndrome (SDS). This syndrome is, however, also associated with significant pancreatic and hepatic dysfunction, which may complicate BMT. We report a case of liver failure due to non-alcoholic steatohepatitis (NASH) following BMT for SDS. This case illustrates the need for assessing liver dysfunction pre-BMT in these patients, in addition to highlighting the potential risk posed by pre-existing steatosis for the development of rapidly progressive hepatic failure following transplantation.


Assuntos
Transplante de Medula Óssea/efeitos adversos , Insuficiência Pancreática Exócrina/terapia , Hepatite/etiologia , Falência Hepática/etiologia , Adulto , Contraindicações , Insuficiência Pancreática Exócrina/complicações , Evolução Fatal , Fígado Gorduroso/complicações , Fígado Gorduroso/etiologia , Fígado Gorduroso/patologia , Feminino , Hepatite/complicações , Hepatite/patologia , Humanos , Falência Hepática/patologia , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/terapia , Transplante Homólogo/efeitos adversos
20.
Nutrition ; 15(9): 661-4, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10467609

RESUMO

The longevity of recipients of liver transplant may be compromised by spinal osteoporosis and vertebral fractures. However, femoral neck fractures are associated with a higher morbidity and mortality than spine fractures. As there is little information on bone loss at this clinically important site of fracture, the aim of this study was to determine whether accelerated bone loss occurs at the proximal femur following transplantation. Bone mineral density and body composition were measured at the femoral neck, lumbar spine and total body, using dual x-ray absorptiometry in 22 men and 19 women, age 46 +/- 1.4 y (mean +/- SEM) before and at a mean of 19 mo after surgery (range 3-44). Results were expressed in absolute terms (g/cm2) and as a z score. Before transplantation, z scores for bone mineral density were reduced at the femoral neck (-0.47 +/- 0.21 SD), trochanter (-0.56 +/- 0.19 SD), Ward's triangle (-0.35 +/- 0.14 SD), lumbar spine (-0.76 +/- 0.13 SD), and total body (-0.78 +/- 0.15 SD) (all P < 0.01 to < 0.001). Following transplantation, bone mineral density decreased by 8.0 +/- 1.7% at the femoral neck (P < or = 0.01) and by 2.0 +/- 1.2% at the lumbar spine (P < or = 0.05). Total weight increased by 12.2 +/- 2.3%, lean mass decreased by 5.7 +/- 1.4%, while fat mass increased from 24.1 +/- 2.0% to 35.1 +/- 1.8% (all P < or = 0.001). Patients with end-stage liver disease have reduced bone mineral density. Liver transplantation is associated with a rapid decrease in bone mineral density at the proximal femur, further increasing fracture risk and a reduction in lean (muscle) mass, which may also predispose to falls. Prophylactic therapy to prevent further bone loss should be considered in patients after liver transplantation.


Assuntos
Composição Corporal , Fêmur , Transplante de Fígado/efeitos adversos , Osteoporose/etiologia , Absorciometria de Fóton , Tecido Adiposo , Adulto , Idoso , Índice de Massa Corporal , Peso Corporal , Densidade Óssea , Feminino , Humanos , Estudos Longitudinais , Vértebras Lombares , Masculino , Pessoa de Meia-Idade
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