RESUMO
BACKGROUND: The extent of liver resection for tumours is limited by the expected functional reserve of the future liver remnant (FRL), so hypertrophy may be induced by portal vein embolization (PVE), taking 6 weeks or longer for growth. This study assessed the hypothesis that simultaneous embolization of portal and hepatic veins (PVE/HVE) accelerates hypertrophy and improves resectability. METHODS: All centres of the international DRAGON trials study collaborative were asked to provide data on patients who had PVE/HVE or PVE on 2016-2019 (more than 5 PVE/HVE procedures was a requirement). Liver volumetry was performed using OsiriX MD software. Multivariable analysis was performed for the endpoints of resectability rate, FLR hypertrophy and major complications using receiver operating characteristic (ROC) statistics, regression, and Kaplan-Meier analysis. RESULTS: In total, 39 patients had undergone PVE/HVE and 160 had PVE alone. The PVE/HVE group had better hypertrophy than the PVE group (59 versus 48 per cent respectively; P = 0.020) and resectability (90 versus 68 per cent; P = 0.007). Major complications (26 versus 34 per cent; P = 0.550) and 90-day mortality (3 versus 16 per cent respectively, P = 0.065) were comparable. Multivariable analysis confirmed that these effects were independent of confounders. CONCLUSION: PVE/HVE achieved better FLR hypertrophy and resectability than PVE in this collaborative experience.
Assuntos
Embolização Terapêutica/métodos , Hepatectomia/métodos , Neoplasias Hepáticas/terapia , Cuidados Pré-Operatórios/métodos , Idoso , Feminino , Seguimentos , Veias Hepáticas , Humanos , Regeneração Hepática , Masculino , Pessoa de Meia-Idade , Veia Porta , Estudos Retrospectivos , Resultado do TratamentoRESUMO
BACKGROUND: Based on excellent outcomes from high-volume centres, laparoscopic liver resection is increasingly being adopted into nationwide practice which typically includes low-medium volume centres. It is unknown how the use and outcome of laparoscopic liver resection compare between high-volume centres and low-medium volume centres. This study aimed to compare use and outcome of laparoscopic liver resection in three leading European high-volume centres and nationwide practice in the Netherlands. METHOD: An international, retrospective multicentre cohort study including data from three European high-volume centres (Oslo, Southampton and Milan) and all 20 centres in the Netherlands performing laparoscopic liver resection (low-medium volume practice) from January 2011 to December 2016. A high-volume centre is defined as a centre performing >50 laparoscopic liver resections per year. Patients were retrospectively stratified into low, moderate- and high-risk Southampton difficulty score groups. RESULTS: A total of 2425 patients were included (1540 high-volume; 885 low-medium volume). The median annual proportion of laparoscopic liver resection was 42.9 per cent in high-volume centres and 7.2 per cent in low-medium volume centres. Patients in the high-volume centres had a lower conversion rate (7.4 versus 13.1 per cent; P < 0.001) with less intraoperative incidents (9.3 versus 14.6 per cent; P = 0.002) as compared to low-medium volume centres. Whereas postoperative morbidity and mortality rates were similar in the two groups, a lower reintervention rate (5.1 versus 7.2 per cent; P = 0.034) and a shorter postoperative hospital stay (3 versus 5 days; P < 0.001) were observed in the high-volume centres as compared to the low-medium volume centres. In each Southampton difficulty score group, the conversion rate was lower and hospital stay shorter in high-volume centres. The rate of intraoperative incidents did not differ in the low-risk group, whilst in the moderate-risk and high-risk groups this rate was lower in high-volume centres (absolute difference 6.7 and 14.2 per cent; all P < 0.004). CONCLUSION: High-volume expert centres had a sixfold higher use of laparoscopic liver resection, less conversions, and shorter hospital stay, as compared to a nationwide low-medium volume practice. Stratification into Southampton difficulty score risk groups identified some differences but largely outcomes appeared better for high-volume centres in each risk group.
Assuntos
Carcinoma Hepatocelular/cirurgia , Hepatectomia/métodos , Hospitais com Alto Volume de Atendimentos/estatística & dados numéricos , Laparoscopia/métodos , Neoplasias Hepáticas/cirurgia , Complicações Pós-Operatórias/epidemiologia , Pontuação de Propensão , Idoso , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Países Baixos/epidemiologia , Estudos Retrospectivos , Fatores de RiscoRESUMO
Tumor Necrosis Factor (TNF) is a multifunctional cytokine. It plays an important role in the pathophysiology of several diseases. Recently, it has been discovered that TNF is circulating in two different forms, a bioactive form and an immunologically detectable form. These two forms of TNF show different clearance kinetics. The immunological form is supposed to be an inactivated TNF protein. For this inactivation, proteolytic degradation or TNF binding by inactivating proteins is necessary. In this review we have focused on TNF inactivation by TNF binding proteins. Recent data show that there are soluble TNF receptors circulating which can bind and inactivate TNF. These receptors are membrane-bound TNF receptors which have been proteolytically cleaved from the cell membrane. Two TNF receptors are circulating, the soluble TNF receptor of 55 kDa (P55) and the receptor of 75 kDa (P75). The receptors are held responsible not only for inactivation of the TNF, but also for the clearance of TNF. Recent data show that the kidney is the most important organ for TNF clearance, followed by the liver. All other organs are of less importance. In this review, function, release, and clearance of TNF are discussed.
Assuntos
Membrana Celular/metabolismo , Inflamação/tratamento farmacológico , Neoplasias/tratamento farmacológico , Receptores do Fator de Necrose Tumoral/imunologia , Fator de Necrose Tumoral alfa/imunologia , Animais , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Antineoplásicos Imunológicos/farmacologia , Antineoplásicos Imunológicos/uso terapêutico , Humanos , Inflamação/genética , Inflamação/imunologia , Inflamação/patologia , Metaloproteases/imunologia , Metaloproteases/metabolismo , Mutação , Neoplasias/genética , Neoplasias/imunologia , Neoplasias/patologia , Proteólise , Receptores do Fator de Necrose Tumoral/antagonistas & inibidores , Receptores do Fator de Necrose Tumoral/genética , Receptores do Fator de Necrose Tumoral/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
BACKGROUND: The impact of postoperative complications on long-term outcomes after surgery for colorectal liver metastases (CRLM) remains controversial. During the last decade, advances in surgical as well as non-surgical treatment have increased resectability and altered outcomes. We sought to determine the influence of postoperative morbidity on disease-free (DFS) and overall survival (OS). METHODS: All patients undergoing liver resection for CRLM for the first time between 2000 and 2011 were retrospectively identified from a prospective database. Postoperative morbidity was classified according to Dindo-Clavien grade. A Dindo-Clavien grade ≥ 3a was considered a major complication. Primary outcomes were DFS and OS depending on the presence or absence of postoperative morbidity. RESULTS: Of the 266 included patients, 97 patients (37 %) developed postoperative complications, of whom 61 (23 %) had major complications. Median DFS and OS (5-year) were 17 and 53 months (42 %). The occurrence of postoperative morbidity did not significantly shorten OS (p = 0.130) and DFS (p = 0.101). However, major morbidity reduced DFS significantly (p < 0.05). CONCLUSION: In the present study, the occurrence of major postoperative complications was associated with diminished DFS. However, the effect of (major) complications on OS did not reach statistical significance.
Assuntos
Neoplasias Colorretais/patologia , Hepatectomia/efeitos adversos , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Humanos , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/mortalidade , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida , Resultado do Tratamento , Adulto JovemRESUMO
OBJECTIVE: To evaluate the use of reproductive health care and incidence of paediatric HIV infection during the expansion of antiretroviral therapy and services for the prevention of mother-to-child transmission in rural Malawi, and the influence of integration of these HIV-related services into general health services. DESIGN: Descriptive analysis. SETTING: Thyolo District, with a population of 600,000, an HIV prevalence of 21% and a total fertility rate of 5.7 in 2004. POPULATION: Women attending reproductive health services care in 2005 and 2010. METHODS: Review of facility records and databases for routine monitoring. MAIN OUTCOME MEASURES: Use of antenatal, intrapartum, postpartum, family planning and sexually transmitted infection services; incidence of HIV infection in infants born to mothers who received prevention of mother-to-child transmission care. RESULTS: There was a marked increase in the uptake of perinatal care: pregnant women in 2010 were 50% more likely to attend at least one antenatal visit (RR 1.50, 95% CI 1.48-1.51); were twice as likely to deliver at a healthcare facility (RR 2.05, 95% CI 2.01-2.08); and were more than four times as likely to present for postpartum care (RR 4.40, 95% CI 4.25-4.55). Family planning consultations increased by 40% and the number of women receiving treatment for sexually transmitted infections doubled. Between 2007 and 2010, the number of HIV-exposed infants who underwent testing for HIV went up from 421 to 1599/year, and the proportion testing positive decreased from 13.3 to 5.0%; infants were 62% less likely to test HIV positive (RR 0.38, 95% CI 0.27-0.52). CONCLUSIONS: During the expansion and integration of HIV care, the use of reproductive health services increased and the outcomes of infants born to HIV-infected mothers improved. HIV care may be successfully integrated into broader reproductive health services.
Assuntos
Infecções por HIV/prevenção & controle , Infecções por HIV/transmissão , HIV-1 , Transmissão Vertical de Doenças Infecciosas/prevenção & controle , Serviços de Saúde Materna , Complicações Infecciosas na Gravidez/prevenção & controle , População Rural , Adulto , Fármacos Anti-HIV/uso terapêutico , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Soropositividade para HIV/transmissão , Necessidades e Demandas de Serviços de Saúde , Humanos , Lactente , Recém-Nascido , Transmissão Vertical de Doenças Infecciosas/estatística & dados numéricos , Malaui/epidemiologia , Serviços de Saúde Materna/normas , Serviços de Saúde Materna/tendências , Gravidez , Complicações Infecciosas na Gravidez/tratamento farmacológico , Complicações Infecciosas na Gravidez/epidemiologia , Prevalência , Saúde Reprodutiva , Estudos Retrospectivos , População Rural/estatística & dados numéricosRESUMO
BACKGROUND: The feasibility of randomized controlled trials (RCTs) in liver surgery using a single-component clinical endpoint is low as such endpoints require large sample sizes owing to their low incidence. A liver surgery-specific composite endpoint (CEP) could solve this problem. The aim of this study was to develop a liver surgery-specific CEP with well-defined components. METHODS: Components of a liver surgery-specific CEP were selected based on a systematic literature search and consensus among 28 international hepatopancreatobiliary (HPB) surgeons. As an example, two prospective cohorts of patients who had undergone liver surgery in high-volume HPB centres were used to assess the event rate and effect of implementing a liver surgery-specific CEP. RESULTS: Components selected for the liver surgery-specific CEP were ascites, postresectional liver failure, bile leakage, intra-abdominal haemorrhage, intra-abdominal abscess and operative mortality, all with a Clavien-Dindo grade of at least 3 and occurring within 90 days after initial surgery. The incidence of this liver surgery-specific CEP was 19.2 per cent in one cohort and 10.7 per cent in the other. These rates led to an approximately twofold reduction in the theoretical sample size required for an adequately powered RCT in liver surgery using the CEP as primary endpoint. CONCLUSION: The proposed liver surgery-specific CEP consists of ascites, postresectional liver failure, bile leakage, intra-abdominal haemorrhage, intra-abdominal abscess and operative mortality. It has a considerably higher event rate than any of its components. Its use as the primary endpoint will increase the feasibility and comparability of RCTs in liver surgery.
Assuntos
Determinação de Ponto Final , Hepatopatias/cirurgia , Ensaios Clínicos Controlados Aleatórios como Assunto , Idoso , Consenso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnósticoRESUMO
BACKGROUND: Accelerated recovery from surgery has been achieved when patients are managed within a multimodal Enhanced Recovery After Surgery (ERAS) protocol. This study evaluated the benefit of an ERAS programme for patients undergoing liver resection. METHODS: The ERAS protocol of epidural analgesia, early oral intake and early mobilization was studied prospectively in a consecutive series of 61 patients. Outcomes were compared with those in a consecutive series of 100 patients who underwent liver resection before the start of the study. Endpoints were postoperative length of hospital stay, postoperative resumption of oral intake, readmissions, morbidity and mortality. RESULTS: Fifty-six patients (92 per cent) in the ERAS group tolerated fluids within 4 h of surgery and a normal diet on day 1 after surgery. Median hospital stay, including readmissions, was 6.0 days compared with 8.0 days in the control group (P < 0.001). There were no significant differences in rates of readmission (13 and 10.0 per cent respectively), morbidity (41 and 31.0 per cent) and mortality (0 and 2.0 per cent) between ERAS and control groups. CONCLUSION: The ERAS fast-track protocol is safe and effective for patients undergoing liver resection. It allows early oral intake, promotes faster postoperative recovery and reduces hospital stay.
Assuntos
Hepatectomia/reabilitação , Tempo de Internação/estatística & dados numéricos , Neoplasias Hepáticas/cirurgia , Cuidados Pós-Operatórios/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgesia Epidural/estatística & dados numéricos , Estudos de Casos e Controles , Protocolos Clínicos , Deambulação Precoce/estatística & dados numéricos , Ingestão de Alimentos/fisiologia , Feminino , Hepatectomia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Readmissão do Paciente/estatística & dados numéricos , Cuidados Pós-Operatórios/estatística & dados numéricos , Avaliação de Programas e Projetos de Saúde , Estudos Prospectivos , Recuperação de Função FisiológicaRESUMO
BACKGROUND: The FIRE-3 trial investigated combination chemotherapy plus either cetuximab or bevacizumab in patients with untreated metastatic colorectal cancer (mCRC) not scheduled for upfront surgery. We aimed to determine the number of patients who present with potentially resectable disease during systemic first-line therapy and to compare the findings with study reports concerning resections and outcome. PATIENTS AND METHODS: This evaluation of 448 patients was performed as central review blinded for treatment, other reviewers' evaluations and conducted interventions. Resectability was defined if at least 50% of the reviewers recommended surgical-based intervention. Overall survival was assessed by Kaplan-Meier method. RESULTS: Resectability increased from 22% (97/448) at baseline before treatment to 53% (238/448) at best response (P < 0.001), compared with an actual secondary resection rate for metastases of 16% (72/448). At baseline (23% versus 20%) and best response (53% versus 53%), potential resectability of metastases in this molecular unselected population was similar in cetuximab-treated patients versus bevacizumab-treated patients and not limited to patients with one-organ disease. The actual resection rate of metastases was significantly associated with treatment setting (P = 0.02; university hospital versus hospital/practice). Overall survival was 51.3 months (95% confidence interval [CI] 35.9-66.7) in patients with resectable disease who received surgery, 30.8 months (95% CI 26.6-34.9) in patients with resectable disease without surgery and 18.6 months (95% CI 15.8-21.3) in patients with unresectable disease (P < 0.001). CONCLUSIONS: Our findings illustrate the potential for conversion to resectability in mCRC, certain reluctance towards metastatic resections in clinical practice and the need for pre-planned and continuous evaluation for metastatic resection in high-volume centres. CLINICALTRIALS. GOV-IDENTIFIER: NCT00433927.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/cirurgia , Avaliação de Resultados em Cuidados de Saúde/métodos , Adulto , Idoso , Bevacizumab/administração & dosagem , Camptotecina/administração & dosagem , Camptotecina/análogos & derivados , Cetuximab/administração & dosagem , Neoplasias Colorretais/patologia , Terapia Combinada , Feminino , Fluoruracila/administração & dosagem , Humanos , Irinotecano , Estimativa de Kaplan-Meier , Leucovorina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricosRESUMO
Tumor Necrosis Factor (TNF) is a multifunctional cytokine. It plays an important role in the pathophysiology of several diseases. Recently, it has been discovered that TNF is circulating in two different forms, a bioactive form and an immunologically detectable form. These two forms of TNF show different clearance kinetics. The immunological form is supposed to be an inactivated TNF protein. For this inactivation, proteolytic degradation or TNF binding by inactivating proteins is necessary. In this review we have focused on TNF inactivation by TNF binding proteins. Recent data show that there are soluble TNF receptors circulating which can bind and inactivate TNF. These receptors are membrane-bound TNF receptors which have been proteolytically cleaved from the cell membrane. Two TNF receptors are circulating, the soluble TNF receptor of 55 kDa (P55) and the receptor of 75 kDa (P75). The receptors are held responsible not only for inactivation of the TNF, but also for the clearance of TNF. Recent data show that the kidney is the most important organ for TNF clearance, followed by the liver. All other organs are of less importance. In this review, function, release, and clearance of TNF are discussed.
Assuntos
Fator de Necrose Tumoral alfa/fisiologia , Animais , Humanos , Leucócitos/metabolismo , Taxa de Depuração Metabólica , Receptores do Fator de Necrose Tumoral/fisiologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Albuminuria and increased regional albumin clearance are known to develop concomitantly in diabetes. The anti-proteinuric effect of angiotensin-converting enzyme inhibitor therapy is well established. We studied whether angiotensin-converting enzyme inhibitor therapy with perindoprilat in comparison with conventional antihypertensive treatment could influence the development of increased regional albumin clearance as well as albuminuria in experimental diabetes. Rats with streptozotocin-induced diabetes were randomized into a saline group (n = 7), a perindoprilat (1 mg/kg per day) group (n = 8), and a hydralazine (3 mg/kg per day) group (n = 6); six rats served as non-diabetic controls. After 6-8 weeks, blood pressure was equally reduced in the perindoprilat- and hydralazine-treated groups (P < 0.01). Twenty-four-hour urinary protein and albumin excretion were increased in diabetic rats compared to control rats (P < 0.001). Hydralazine did not reduce 24 h protein or albumin excretion, whereas perindoprilat treatment reduced both (P < 0.001) to levels comparable to those of control rats. Regional albumin clearance, assessed in the eye, ileum, lung, skeletal muscle and skin, was clearly elevated in diabetic rats compared to control rats; however, neither drug therapy had an effect on albumin clearance.
Assuntos
Albuminas/metabolismo , Albuminúria/tratamento farmacológico , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Permeabilidade Capilar/efeitos dos fármacos , Diabetes Mellitus Experimental/fisiopatologia , Indóis/farmacologia , Albuminúria/metabolismo , Animais , Anti-Hipertensivos/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Diabetes Mellitus Experimental/urina , Hidralazina/farmacologia , Masculino , Distribuição Aleatória , Ratos , Ratos WistarRESUMO
BACKGROUND AND AIMS: In the era of expanding costs of healthcare, this study was conducted to perform a cost analysis of introducing a laparoscopic liver surgery programme for left sided liver lesions. MATERIALS AND METHODS: Consecutive patients treated by laparoscopic liver resections of left lateral segments were included. Controls were a group of 14 patients undergoing open resection for similar pathology. Primary outcomes were costs. Secondary outcomes were complications, conversions, blood loss, length of operation, and length of hospital stay. RESULTS: The laparoscopic approach for hepatic left lateral resection (bisegmentectomy 2 and 3) was performed in fourteen patients (group I, median age 54 [range 26-82] years). In the open group, fourteen patients from a prospectively collected database with the same type of resection were selected (group II, median age 64 [range 29-76] years). Costs of theatre usage in the laparoscopic group were significantly lower (p=0.031). No significant differences in costs of disposable instruments, ward stay and total costs were observed between the two groups. There were three complications in the laparoscopic group compared with two complications in the open group. In the laparoscopic group there were 2 conversions (14%). Median blood loss was significantly lower in the laparoscopic group (50 mls [range 0-750], (p=0.001) versus the open group (500 mls [range 150-750]). Furthermore, operation time was also significantly lower in the laparoscopic group (116 [range 85-261] minutes) versus the open group (165 [range 96-217] minutes, p=0.016). Median length of stay was 6 [range 4-11] days in group I versus 6 [range 5-13] days in group II (p=0.508). CONCLUSION: Costs of laparoscopic liver resections proved to be equivalent to open surgery. Furthermore, implementation of a laparoscopic liver resection programme seems feasible and safe with reduced blood loss and operation time and comparable morbidity and length of stay.
Assuntos
Custos Hospitalares , Hospitais Universitários/economia , Laparoscopia/economia , Neoplasias Hepáticas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Perda Sanguínea Cirúrgica , Efeitos Psicossociais da Doença , Custos e Análise de Custo , Feminino , Humanos , Tempo de Internação , Neoplasias Hepáticas/economia , Masculino , Pessoa de Meia-Idade , Países BaixosRESUMO
OBJECTIVE: To report on the trends in new and recurrent tuberculosis (TB) case notifications in a rural district of Malawi that has embarked on large-scale roll-out of antiretroviral treatment (ART). METHODS: Descriptive study analysing TB case notification and ART enrolment data between 2002 and 2009. RESULTS: There were a total of 10,070 new and 755 recurrent TB cases. ART scale-up started in 2003, and by 2007 an estimated 80% ART coverage had been achieved and was sustained thereafter. For new TB cases, an initial increase in case notifications in the first years after starting ART (2002-2005) was followed by a highly significant and sustained decline from 259 to 173 TB cases per 100,000 population (χ(2) for trend 261, P < 0.001, cumulative reduction for 2005-2009 = 33%, 95%CI 27-39). For recurrent TB, the initial increase was followed by a significant drop, from 20 to 15 cases/100,000 (χ(2) for linear trend = 8.3, P = 0.004, constituting a 25% (95%CI 9-49) cumulative reduction between 2006 and 2009. From 2005 to 2009, ART averted an estimated 1164 (95%CI 847-1480) new TB cases and 78 (95%CI 23-151) recurrent TB cases. CONCLUSIONS: High ART implementation coverage is associated with a very significant declining trend in new and recurrent TB case notifications at population level.
Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , Tuberculose/epidemiologia , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Notificação de Doenças/estatística & dados numéricos , Infecções por HIV/complicações , Humanos , Malaui/epidemiologia , Recidiva , Estudos Retrospectivos , Tuberculose/etiologiaAssuntos
Neoplasias Gástricas/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Gastrectomia/métodos , Gastrectomia/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Cuidados Paliativos , Prognóstico , Estudos Retrospectivos , Neoplasias Gástricas/mortalidade , Neoplasias Gástricas/patologiaRESUMO
TNF, a primary mediator of the response to infection, can be injurious to the organism when present in excessive quantities. Circulating soluble TNF receptors (sTNFR) appear to represent a natural mechanism that protects against circulating TNF. Two soluble TNF receptors (sTNFR-P55 and sTNFR-P75) circulate in vivo and are up-regulated in response to endotoxin. In this study, we investigated the kinetics of LPS-induced sTNFR release and the role of the cytokines TNF, leukemia inhibiting factor, IFN-gamma, and IL-1 in this process. The results show that LPS injection results in a rapid increase in levels of both sTNFR. Although sTNFR-P55 decreases after a peak at 30 min, sTNFR-P75 levels show a peak after 4 to 8 h, after which they slowly diminish. Both human TNF and murine TNF are capable of increasing levels of both sTNFR. Blocking circulating TNF by administration of 3 different anti-TNF agents before LPS injection (mAb to murine TNF, sTNFR55-Fc or sTNFR75-Fc) results in a significant increase of sTNFR-P55 levels, whereas only both sTNFR-Fc constructs also significantly increase sTNFR-P75 levels. Although IL-1 receptor antagonist pretreatment before LPS has no effect on TNF or sTNFR levels, leukemia inhibiting factor pretreatment significantly increases sTNFR-P55 levels. Pretreatment with anti IFN-gamma mAb before LPS results in a significant reduction in TNF and sTNFR-P55 levels, but sTNFR-P75 levels are significantly increased. Our data show that both sTNFR can be up-regulated by LPS and TNF. The influence of TNF, leukemia inhibiting factor, IL-1, and IFN-gamma on the kinetics of LPS-induced circulating sTNFR is discussed in the context of the pathophysiology of LPS-induced disease.
Assuntos
Inibidores do Crescimento/fisiologia , Interferon gama/fisiologia , Interleucina-1/fisiologia , Interleucina-6 , Lipopolissacarídeos/farmacologia , Linfocinas/fisiologia , Receptores do Fator de Necrose Tumoral/metabolismo , Fator de Necrose Tumoral alfa/fisiologia , Animais , Feminino , Fator Inibidor de Leucemia , CamundongosRESUMO
In this study, clearance of sTNFR was investigated. The data show that bilateral nephrectomy results in an increase of the levels of both sTNFR after which a new steady state situation develops, suggesting that other organs, apart from the kidneys, are involved in clearing of sTNFR. Bilateral nephrectomy also leads to an increase in circulating TNF. This TNF was detected by ELISA and appeared to be not biologically active. To investigate whether the endotoxin induced increase in sTNFR is dependent of renal function, endotoxin was injected in nephrectomized mice. The data show that nephrectomy followed by endotoxin injection resulted in a further increase of the levels of both sTNFR. However, the endotoxin induced increase in nephrectomized mice was similar to the situation in normal mice after LPS indicating that the endotoxin induced increase is kidney independent in these mice. To investigate the relative participation of various organs in sTNFR clearance, 125I labelled sTNFR-P75 was injected. The data reveal that the majority of the sTNFR is removed from the circulation by the kidneys although indications for involvement of the liver and the lungs were also obtained. Calculation of the parametric clearance revealed that nephrectomy resulted in a 50% reduction of sTNFR-P75 clearance. Furthermore, the data presented strongly suggest that sTNFR release seems to be a continuous process, which is in balance with clearance of the sTNFR by the kidney, although other organs such as the liver and the lungs are involved.
Assuntos
Receptores do Fator de Necrose Tumoral/metabolismo , Animais , Bile/metabolismo , Eletroforese em Gel de Poliacrilamida , Feminino , Radioisótopos do Iodo , Cinética , Lipopolissacarídeos/farmacologia , Camundongos , Nefrectomia , Especificidade de Órgãos , Receptores do Fator de Necrose Tumoral/análise , Receptores do Fator de Necrose Tumoral/isolamento & purificação , Valores de Referência , Fatores de TempoRESUMO
TNF, a cytokine with multiple properties, is known to be rapidly inactivated in vivo. In patients with septic shock and kidney malfunction, conflicting data have been reported regarding the presence of TNF in the circulation. Recently, we have shown that these differences can be the result of the detection of free TNF vs TNF complexed with soluble TNF-R. Enhanced levels of soluble TNF-R have been reported in patients with kidney malfunction. Because the kidney is thought to play an important role in TNF and TNF-R metabolism, we investigated the influence of bilateral nephrectomy on TNF clearance and TNF-R regulation in a murine model. The data obtained show that bilateral nephrectomy results in circulating levels of immunologically detectable (ELISA), but not biologically active (bioassay), TNF. Injection of endotoxin results in significantly higher levels of immunologically detectable TNF in bilaterally nephrectomized mice, compared with sham-operated mice, whereas biologically active levels were similar. To investigate the roles of TNF-R1 (P55) and TNF-R2 (P75) in this process, clearance of TNF was studied by injection of murine and human TNF. Murine TNF injection leads to comparable clearance of bioactive TNF in nephrectomized and sham-operated mice (t1/2 = approximately 12 min). However, clearance of immunologically detectable murine TNF is significantly slower in nephrectomized mice, compared with sham-operated mice (t1/2 = 96 min vs 26 min, respectively; p < 0.05). Administration of human TNF results in a significantly lower clearance in nephrectomized mice, compared with sham-operated mice (t1/2 = 108 min vs 25 min, respectively; p < 0.05). This is observed for both bioactive human TNF and immunologically detectable human TNF. Based on the fact that murine TNF-R1 (55 kDa) has a similar affinity for murine and human TNF, whereas murine TNF-R2 (75 kDa) shows affinity only for murine TNF, the data obtained suggest an important role for TNF-R2 in inactivation and clearance of TNF by the kidney. Moreover, the data suggest that kidney malfunction affects TNF clearance, leading to increased amounts of circulating TNF-TNF-R complexes, which could function as a slow release reservoir for TNF.
Assuntos
Nefrectomia , Fator de Necrose Tumoral alfa/metabolismo , Adrenalectomia , Animais , Feminino , Meia-Vida , Humanos , Rim/metabolismo , Lipopolissacarídeos , Taxa de Depuração Metabólica , Camundongos , Testes de Precipitina , Coelhos , Proteínas Recombinantes/metabolismo , Fator de Necrose Tumoral alfa/imunologiaRESUMO
Tumour necrosis factor (TNF) may play an important role in the increased incidence of complications after surgery in patients with obstructive jaundice. This study evaluated the effect of three different anti-TNF treatments, a monoclonal anti-TNF antibody (TN3), pentoxifylline and lactulose, on outcome after severe surgical trauma in mice with experimental biliary obstruction. Circulating serum TNF levels and mortality rate were monitored. Severe surgical trauma, such as renal ischaemia, in jaundiced mice resulted in increased levels of circulating TNF (3.5 ng/ml) and a high mortality rate (54 per cent). The three different anti-TNF treatments caused a significant reduction in postoperative levels of circulating TNF (TN3, P < 0.001; pentoxifylline, P < 0.01; lactulose, P < 0.05). Treatment with TN3 and pentoxifylline did not lead to a significantly reduced mortality rate (36 and 44 per cent respectively). Only lactulose treatment produced a significantly reduced mortality rate (7 per cent, P < 0.01). TNF is therefore not the only mediator responsible for death after surgery in jaundiced mice. Other mechanisms affected by lactulose are also involved.
Assuntos
Anticorpos Monoclonais/farmacologia , Ductos Biliares/cirurgia , Colestase/sangue , Lactulose/farmacologia , Pentoxifilina/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Colestase/mortalidade , Feminino , Rim/irrigação sanguínea , Camundongos , Fator de Necrose Tumoral alfa/imunologiaRESUMO
The repetitive administration of low doses of hTNF to mice induces tolerance to the lethal effects of mTNF. The underlying mechanism is unknown. In this study we have investigated whether changes in bioavailability and receptor binding could account for the observed differences. To that end we compared the pharmacokinetics of mTNF, the antibody response to TNF, the levels of soluble TNF receptors and the receptor binding of TNF in tolerant and control mice. No differences in pharmacokinetic parameters were observed. An antibody response towards hTNF occurred but the antibodies did not neutralize the mTNF used as a challenge. Furthermore, tolerance failed to protect mice against lethality induced by TNF in the presence of galactosamine, where 100- to 1000-fold lower dose of TNF is required. Also, tolerance could be induced in athymic nude mice where the antibody response is absent. These results show that the mechanism of induction of tolerance is not due to an antibody response. No differences in levels of soluble receptors or receptor binding could be observed in tolerant vs control mice. We conclude that the induction of tolerance involves mechanisms operating at the post-receptor pathways.
Assuntos
Tolerância Imunológica/efeitos dos fármacos , Fator de Necrose Tumoral alfa/farmacologia , Fator de Necrose Tumoral alfa/farmacocinética , Animais , Formação de Anticorpos , Disponibilidade Biológica , Membrana Celular/metabolismo , Feminino , Galactosamina/toxicidade , Humanos , Cinética , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Receptores do Fator de Necrose Tumoral/metabolismo , Proteínas Recombinantes/farmacocinética , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/toxicidade , Fator de Necrose Tumoral alfa/toxicidadeRESUMO
Injection of anti-CD3 is accompanied by an increase in systemic TNF, a mediator of the physiologic changes induced by anti-CD3 injection. Various mechanisms have been reported to be responsible for TNF inactivation and clearance. Recently, it has become evident that circulating soluble TNFRs (P55 and P75), which are known to increase in response to TNF inducers such as LPS, represent a natural protection mechanism against circulating TNF. Here we show that triggering the TCR by anti-CD3 injection results in a strong induction of both systemic TNF and soluble TNFR release. Maximal levels of TNF were reached after 2 h (10 ng/ml). Maximum levels of P55 (450 pg/ml) were reached between 0.5 and 8 h, whereas the highest levels of P75 were reached after 2 h (28 ng/ml). Because TNF and IFN-gamma are supposed to be involved in the pathophysiology of the anti-CD3 response, we investigated the influence of in vivo neutralization of TNF and IFN-gamma. Injection of mAb to TNF and IFN-gamma significantly reduced systemic TNF levels and both soluble TNFR levels. Two inhibitors of anti-CD3 induced TNF release; steroids and pentoxifylline both reduced TNF levels and P75 levels without affecting P55 levels. The results show that T cell activation induces both systemic TNF release and release of both soluble TNFRs. Although TNF and IFN-gamma are involved in this mechanism, their role does not seem to be crucial.