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1.
Thromb Res ; 237: 79-87, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38555718

RESUMO

BACKGROUND: Acquired hemophilia A (AHA) is a rare autoimmune disorder due to autoantibodies against Factor VIII, with a high mortality risk. Treatments aim to control bleeding and eradicate antibodies by immunosuppression. International recommendations rely on registers and international expert panels. METHODS: CREHA, an open-label randomized trial, compared the efficacy and safety of cyclophosphamide and rituximab in association with steroids in patients with newly diagnosed AHA. Participants were treated with 1 mg/kg prednisone daily and randomly assigned to receive either 1.5-2 mg/kg/day cyclophosphamide orally for 6 weeks, or 375 mg/m2 rituximab once weekly for 4 weeks. The primary endpoint was complete remission over 18 months. Secondary endpoints included time to achieve complete remission, relapse occurrence, mortality, infections and bleeding, and severe adverse events. RESULTS: Recruitment was interrupted because of new treatment recommendations after 108 patients included (58 cyclophosphamide, 50 rituximab). After 18 months, 39 cyclophosphamide patients (67.2 %) and 31 rituximab patients (62.0 %) were in complete remission (OR 1.26; 95 % CI, 0.57 to 2.78). In the poor prognosis group (FVIII < 1 IU/dL, inhibitor titer > 20 BU mL-1), significantly more remissions were observed with cyclophosphamide (22 patients, 78.6 %) than with rituximab (12 patients, 48.0 %; p = 0.02). Relapse rates, deaths, severe infections, and bleeding were similar in the 2 groups. In patients with severe infection, cumulative doses of steroids were significantly higher than in patients without infection (p = 0.03). CONCLUSION: Cyclophosphamide and rituximab showed similar efficacy and safety. As first line, cyclophosphamide seems preferable, especially in poor prognosis patients, as administered orally and less expensive. FUNDING: French Ministry of Health. CLINICALTRIALS: gov number: NCT01808911.

2.
Rev Med Interne ; 43(8): 494-497, 2022 Aug.
Artigo em Francês | MEDLINE | ID: mdl-35637030

RESUMO

The occurrence of acquired hemophilia during pregnancy or postpartum is rare (2 to 10 % in series). It is generally suspected in the presence of haemorrhagic manifestations (especially subcutataneous or mucosal bleeding) associated with an isolated prolongation of the activated partial thromboplastin time (APTT). The diagnosis is confirmed by the association of a low level of factor VIII (FVIII) and the presence of an anti-FVIII inhibitor. Postpartum management is similar to that of other acquired haemophilias: correction of a severe haemorrhagic syndrome by "bypassing" agents, eradication of the inhibitor by corticosteroids alone or in combination with another immunosuppressive agent depending on the residual level of FVIII and the titer of the inhibitor. Management of the forms occurring during pregnancy is based on rare experiences or expert opinions. The management of childbirth is particularly delicate in terms of haemorrhage, especially if the anti-FVIII inhibitor is still present, and must be prepared in a multidisciplinary manner. Finally, as with any acquired hemophilia, a relapse is possible, especially in the year following remission. During a subsequent pregnancy, the risk of recurrence is possible but should not be a contraindication to a new pregnancy.


Assuntos
Hemofilia A , Corticosteroides , Fator VIII , Feminino , Hemofilia A/diagnóstico , Hemofilia A/etiologia , Hemofilia A/terapia , Humanos , Imunossupressores/uso terapêutico , Gravidez
3.
Rev Med Interne ; 43(3): 139-144, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34344579

RESUMO

PURPOSE: Acquired hemophilia (AH) is a rare, serious bleeding disorder most often associated with older age and life-threatening complications. The patient care pathway for AH is complex because of the different types of bleeding, the presence of comorbidities, and the heterogeneity of medical specialists who care for these patients. METHODS: This observational study used the French national PMSI (Programme de médicalisation des systèmes d'information) database to characterize patients with AH in real-life practice and analyze their hospital pathway. In total, 180 patients with AH were identified over a 5-year study period (January 2010 to December 2014), based on three criteria: bypassing agent use, International Classification of Diseases, 10th revision code allocation, and aged over 65 years. Comparison of the incidence rate of AH versus registry data validated the PMSI as an epidemiological database. RESULTS: Rituximab was prescribed more often (60/180; 33.3%) than expected following guidelines and was associated in half of cases to early infections (32/60; 53.3%), surgery procedures were frequently performed during the year before AH onset (29/159; 18.2%), which may suggest a triggering effect, extended hospital stays (median: 20 days) and mortality remaining high (66/180; 36.7%) that occurred mainly during the first month after AH diagnosis. Median costs and number of injections were comparable between recombinant activated factor VII and plasma-derived activated prothrombin complex concentrate. CONCLUSION: These findings could inform future medico-economic approaches in this AH population (duration of stays, bypassing agents, rituximab use, comorbidities, hospitalizations with infections).


Assuntos
Hemofilia A , Idoso , Bases de Dados Factuais , França/epidemiologia , Hemofilia A/epidemiologia , Hemofilia A/terapia , Hospitalização , Hospitais , Humanos , Incidência
5.
Cardiovasc Intervent Radiol ; 42(8): 1175-1182, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31025052

RESUMO

PURPOSE: Arterial embolization has been shown to be effective and safe for the management of bleeding, especially for postpartum and pelvic traumatic bleeding. We propose to evaluate the proof of concept of feasibility and effectiveness of arterial embolization with absorbable and non-absorbable sutures in a porcine model. MATERIALS AND METHODS: In the acute setting (n = 1), several different arteries (mesenteric, splenic, pharyngeal, kidney) were embolized using non-absorbable sutures (NAS): Mersutures™ braided sutures (polyethylene terephthalate). In the chronic setting (n = 3), only lower pole renal arteries were embolized. On the right side, NAS was used, whereas on the left side embolization was realized with absorbable suture (AS): Vicryl® braided suture (polyglactin 910). The chronic group was followed for 3 months. The pigs received contrast-enhanced CT the day before embolization (D-1), after the embolization (D0), at 1 month and 3 months after embolization (M1 and M3); digital subtraction angiography (DSA) was done at D0 and M3 and histological analysis at M3. RESULTS: All vascular targets were effectively embolized without any pre- or postoperative complications. Both DSAs and CTs at M3 showed a 100% recanalization rate for the AS embolization and a partial reversal rate for the NAS embolization. A renal hypotrophy in the embolized region was observed during both the M1 and M3 scans for both sutures (AS and NAS) with a clear hypotrophy for the NAS embolized kidney. CONCLUSION: Embolization by AS and NAS (FAIR-Embo) is a feasible and effective treatment which opens up the possibility of global use of this inexpensive and widely available embolization agent.


Assuntos
Implantes Absorvíveis , Artérias/cirurgia , Embolização Terapêutica/instrumentação , Polietilenotereftalatos , Poliglactina 910 , Suturas , Angiografia Digital , Animais , Artérias/diagnóstico por imagem , Embolização Terapêutica/métodos , Estudos de Viabilidade , Seguimentos , Modelos Animais , Suínos , Tomografia Computadorizada por Raios X , Resultado do Tratamento
6.
Haemophilia ; 24(2): 211-220, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28815880

RESUMO

INTRODUCTION: Nuwiq® (Human-cl rhFVIII) is a fourth generation recombinant FVIII, produced in a human cell line, without chemical modification or protein fusion. No inhibitors developed in studies with Nuwiq® in 201 previously treated patients with haemophilia A (HA). The immunogenicity, efficacy and safety of Nuwiq® in previously untreated patients (PUPs) with severe HA are being assessed in the ongoing NuProtect study. METHODS: The study, conducted across 38 centres worldwide, is evaluating 110 true PUPs of all ages and ethnicities enrolled for study up to 100 exposure days (EDs) or 5 years maximum. The primary objective is to assess the immunogenicity of Nuwiq® (inhibitor activity ≥0.6 BU) using the Nijmegen-modified Bethesda assay at a central laboratory. RESULTS: Data for 66 PUPs with ≥20 EDs from a preplanned interim analysis were analysed. High-titre (HT) inhibitors developed in 8 of 66 patients after a median of 11.5 EDs (range 6-24). Five patients developed low-titre inhibitors (4 transient). The cumulative incidence (95% confidence interval) was 12.8% (4.5%, 21.2%) for HT inhibitors and 20.8% (10.7%, 31.0%) for all inhibitors. During inhibitor-free periods, median annualized bleeding rates during prophylaxis were 0 for spontaneous bleeds and 2.40 for all bleeds. Efficacy was rated as "excellent" or "good" in treating 91.8% of bleeds. Efficacy of surgical prophylaxis was "excellent" or "good" for 8 (89%) procedures and "moderate" for 1 (11%). No tolerability concerns were evident. CONCLUSION: These interim data show a cumulative incidence of 12.8% for HT inhibitors and convincing efficacy and tolerability in PUPs treated with Nuwiq® .


Assuntos
Hemofilia A/imunologia , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Cães , Humanos , Estudos Prospectivos , Adulto Jovem
7.
Oncogene ; 35(42): 5489-5500, 2016 10 20.
Artigo em Inglês | MEDLINE | ID: mdl-27065325

RESUMO

CD146 (MUC-18, MCAM) expression on cancer cells correlates with cancer progression and a bad prognosis in several tumors, including melanoma and pancreatic tumors. Deciphering the mechanism mediating the CD146 role in cancer is essential for generating new therapeutic strategies. We found that CD146 expression in cancer cells is associated with a secretion of soluble CD146 (sCD146) that constitutes an active player in tumor development. Indeed, sCD146 induces the overexpression of its binding protein, angiomotin, on both endothelial and cancer cells and promotes both paracrine effects on angiogenesis and autocrine effects on cancer cells proliferation and survival. These last effects are mediated in part through the induction and phosphorylation of c-myc in cancer cells. In mice models xenografted with human CD146-positive melanoma or pancreatic cancer cells, administration of a novel monoclonal antibody specifically targeting sCD146, but not its membrane form, successfully suppresses tumor vascularization and growth. Our findings demonstrate that sCD146 secreted by CD146-positive tumors mediates important pro-angiogenic and pro-tumoral effects. Targeting sCD146 with a novel neutralizing antibody could thus constitute an innovative therapeutic strategy for the treatment of CD146-positive tumors.


Assuntos
Anticorpos Monoclonais/farmacologia , Anticorpos Neutralizantes/farmacologia , Antígeno CD146/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia , Neovascularização Patológica/metabolismo , Angiomotinas , Animais , Apoptose/efeitos dos fármacos , Biomarcadores , Antígeno CD146/imunologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Células Endoteliais/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Nus , Proteínas dos Microfilamentos , Neoplasias/tratamento farmacológico , Neoplasias/mortalidade , Neovascularização Patológica/tratamento farmacológico , Ligação Proteica , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Haemophilia ; 19(4): 564-70, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23574453

RESUMO

Although extremely rare, acquired haemophilia A (AHA) can cause severe bleeding, which may be fatal. The underlying causes of autoantibody development are not fully understood. Treatment goals are bleeding control and autoantibody eradication. At the time of our study, there was no consensus on a standard treatment strategy for AHA. Previous data were mainly retrospective or from single-centre cohorts. We conducted a prospective, controlled, registry-based study of patients with AHA in France. The prospective French registry (Surveillance des Auto antiCorps au cours de l'Hémophilie Acquise [SACHA]) collected data on prevalence, clinical course, disease associations and outcomes for haemostatic treatment and autoantibody eradication in 82 patients with a 1-year follow-up. Similar to earlier studies, the prevalence of AHA was higher in the elderly, with two thirds of patients aged >70 years. Around half of AHA cases were associated with underlying disease, most commonly autoimmune disease and cancer in younger and older patients respectively. Haemostatic treatment was initially administered to 46% of patients. Complete resolution or improvement of initial bleeding occurred in 22/27 (81%) rFVIIa-treated patients and in all six cases receiving pd-aPCC. The majority of patients (94%) received immunosuppressive therapy, with complete remission at 3 months in 61% (36/59) and in 98% (50/51) at 1 year. Overall mortality was 33%: secondary to bleeding in only three patients but to sepsis in 10. Bypassing agents were effective at controlling bleeding in patients with AHA. Immunosuppressive therapy should be used early but with caution, particularly in elderly patients.


Assuntos
Hemofilia A/tratamento farmacológico , Hemofilia A/epidemiologia , Sistema de Registros , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Autoanticorpos/imunologia , Causas de Morte , Fator VIII/imunologia , Feminino , França/epidemiologia , Hemofilia A/complicações , Hemofilia A/mortalidade , Hemorragia/complicações , Hemorragia/tratamento farmacológico , Hemostáticos/uso terapêutico , Humanos , Imunossupressores/uso terapêutico , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Resultado do Tratamento
9.
Rev Neurol (Paris) ; 169(4): 291-306, 2013 Apr.
Artigo em Francês | MEDLINE | ID: mdl-23246427

RESUMO

INTRODUCTION: Stroke is one of the leading causes of death and disability worldwide. Intravenous recombinant tissue plasminogen activator is the only available therapy for acute ischemic stroke, but its use is limited by a narrow therapeutic window and cannot stimulate endogenous repair and regeneration of damaged brain tissue. Stem cell-based approaches hold much promise as potential novel treatments to restore neurological function after stroke. STATE OF THE ART: In this review, we summarize data from preclinical and clinical studies to investigate the potential application of stem cell therapies for treatment of stroke. Stem cells have been proposed as a potential source of new cells to replace those lost due to central nervous system injury, as well as a source of trophic molecules to minimize damage and promote recovery. Various stem cells from multiple sources can generate neural cells that survive and form synaptic connections after transplantation in the stroke-injured brain. Stem cells also exhibit neurorevitalizing properties that may ameliorate neurological deficits through stimulation of neurogenesis, angiogenesis and inhibition of inflammation. PERSPECTIVES/CONCLUSION: Performed in stroke, cell therapy would decrease brain damage and reduce functional deficits. After the damage has been done, it would still improve neurological functions by activating endogenous repair. Nevertheless, many questions raised by experimental studies particularly related to long-term safety and technical details of cell preparation and administration must be resolved before wider clinical use.


Assuntos
Transplante de Células-Tronco , Acidente Vascular Cerebral/terapia , Animais , Isquemia Encefálica/patologia , Humanos , Células-Tronco Neurais/fisiologia , Resultado do Tratamento
10.
J Thromb Haemost ; 10(9): 1914-28, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22738133

RESUMO

BACKGROUND: Endothelial colony-forming cells (ECFCs) are promising candidates for cell therapy of ischemic diseases. Erythropoietin (EPO) is a cytokine that promotes angiogenesis after ischemic injury. EPO receptors (EPORs) classically include two EPOR subunits, but may also associate with the ß-common chain (CD131) in a newly identified receptor involved in EPO cytoprotective effects. OBJECTIVE: The aim was to take advantage of the proangiogenic properties of EPO to enhance ECFC graft efficiency. We postulated that priming ECFCs by adding epoietin α in culture medium prior to experiments might increase their angiogenic properties. We also explored the role of the CD131 subunit in EPO priming of ECFCs. METHODS AND RESULTS: By western blotting on cord blood ECFC lysates, we showed that EPOR and CD131 expression increased significantly after EPO priming. These proteins coimmunoprecipitated and colocalized, suggesting that they are covalently bound in ECFCs. EPO at 5 IU mL(-1) significantly stimulated proliferation, wound healing, migration and tube formation of ECFCs. EPO priming also increased ECFC resistance to H2 O2-induced apoptosis and survival in vivo. Similarly, in vivo studies showed that, as compared with non-primed ECFC injection, 5 IU mL(-1) EPO-primed ECFCs, injected intravenously 24 h after hindlimb ischemia in athymic nude mice, increased the ischemic/non-ischemic ratios of hindlimb blood flow and capillary density. These effects were all prevented by CD131 small interfering RNA transfection, and involved the phosphoinositide 3-kinase-Akt pathway. CONCLUSION: These results highlight the potential role of EPO-primed ECFCs for cell-based therapy in hindlimb ischemia, and underline the critical role of CD131 as an EPO coreceptor.


Assuntos
Subunidade beta Comum dos Receptores de Citocinas/metabolismo , Endotélio Vascular/efeitos dos fármacos , Eritropoetina/farmacologia , Neovascularização Fisiológica , Células-Tronco/efeitos dos fármacos , Animais , Células Cultivadas , Subunidade beta Comum dos Receptores de Citocinas/genética , Modelos Animais de Doenças , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , Humanos , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , RNA Interferente Pequeno , Células-Tronco/citologia , Células-Tronco/metabolismo , Regulação para Cima
12.
Pharmacol Ther ; 128(3): 445-59, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20732352

RESUMO

Over the past 15 years, a large body of evidence has revealed that the cytokine erythropoietin exhibits non-erythropoietic functions, especially tissue-protective effects. The discovery of EPO and its receptors in the central nervous system and the evidence that EPO is made locally in response to injury as a protective factor in the brain have raised the possibility that recombinant human EPO (rhEPO) could be administered as a cytoprotective agent after acute brain injuries. This review highlights the potential applications of rhEPO as a neuroprotectant in experimental and clinical settings such as ischemia, traumatic brain injury, and subarachnoid and intracerebral hemorrhage. In preclinical studies, EPO prevented apoptosis, inflammation, and oxidative stress induced by injury and exhibited strong neuroprotective and neurorestorative properties. EPO stimulates vascular repair by facilitating endothelial progenitor cell migration into the brain and neovascularisation, and it promotes neurogenesis. In humans, small clinical trials have shown promising results but large prospective randomized studies failed to demonstrate a benefit of EPO for brain protection and showed unwanted side effects, especially thrombotic complications. Recently, regions have been identified within the EPO molecule that mediate tissue protection, allowing the development of non-erythropoietic EPO variants for neuroprotection conceptually devoid of side effects. The efficacy and the safety profile of these new compounds are still to be demonstrated to obtain, in patients, the benefits observed in experimental studies.


Assuntos
Encefalopatias/tratamento farmacológico , Lesões Encefálicas/tratamento farmacológico , Eritropoetina/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Receptores da Eritropoetina/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encefalopatias/fisiopatologia , Lesões Encefálicas/fisiopatologia , Ensaios Clínicos como Assunto , Eritropoetina/efeitos adversos , Eritropoetina/metabolismo , Eritropoetina/farmacologia , Humanos , Neurogênese/efeitos dos fármacos , Fármacos Neuroprotetores/efeitos adversos , Fármacos Neuroprotetores/farmacologia , Proteínas Recombinantes , Transdução de Sinais
13.
Toxicol In Vitro ; 23(8): 1450-4, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19591918

RESUMO

Cross-species differences between human and fish estrogen receptor (ER) binding by environmental chemicals have been reported. To study ER transactivation in a fish cellular context, we stably co-transfected the PLHC-1 fish hepatoma cell line with a rainbow trout estrogen receptor (rtER) and the luciferase reporter gene driven by an estrogen response element (ERE). This new cell model, called PELN-rtER (for PLHC-1-ERE-Luciferase-Neomycin), responded to 17beta-estradiol (E2) in a both concentration- and temperature-dependent manner, as well as to environmental ER ligands from different chemical classes: natural and synthetic estrogens, zearalenone metabolites, genistein, alkyphenoles and benzophenone derivatives. The comparison with other in vitro models, i.e. human reporter cell lines (HELN-rtER, MELN) and vitellogenin induction in primary cultures of rainbow trout hepatocytes, showed an overall higher sensitivity of the human cells for a majority of ligands, except for benzophenone derivatives which were active at similar or lower concentrations in fish cells, suggesting species-specificity for these substances. Correlation analyses suggest that the fish cell line is closer to the trout hepatocyte than to the human cell context, and could serve as a relevant mechanistic tool to study ER activation in fish hepatic cellular context.


Assuntos
Estrogênios/farmacologia , Receptores de Estrogênio/efeitos dos fármacos , Ativação Transcricional/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Células Cultivadas , Relação Dose-Resposta a Droga , Estradiol/farmacologia , Peixes , Genisteína/farmacologia , Hepatócitos/efeitos dos fármacos , Luciferases/genética , Masculino , Oncorhynchus mykiss , Receptores de Estrogênio/genética , Especificidade da Espécie , Temperatura , Vitelogeninas/biossíntese , Zeranol/farmacologia
14.
Rev Med Interne ; 28(12): 862-5, 2007 Dec.
Artigo em Francês | MEDLINE | ID: mdl-17707554

RESUMO

INTRODUCTION: Acquired hemophilia due to an inhibitor of factor VIII is a rare clinical situation. EXEGESIS: Rituximab is now used in the treatment of acquired hemophilia. We report two cases of acquired hemophilia treated by rituximab with efficiency. CONCLUSION: Rituximab appears to be a first line immunosuppressive therapy in acquired hemophilia, especially in post-partum hemophilia.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Hemofilia A/tratamento farmacológico , Fatores Imunológicos/uso terapêutico , Adulto , Idoso , Anticorpos Monoclonais Murinos , Fator VIII/metabolismo , Feminino , Humanos , Rituximab
15.
Neuroscience ; 137(1): 231-9, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16289353

RESUMO

BACKGROUND: The mechanisms underlying the neuroprotective effects of the immunosuppressant tacrolimus, observed in vivo, remain unclear. Here we quantify these effects in vitro, and evaluate the potential involvement of the glutamate and/or immunophilin FK506 binding protein 12 kDa in tacrolimus-induced neuroprotection. METHODS: Primary cultures of neurons and astrocytes from rat cerebral cortex were subjected to transient oxygen-glucose deprivation. Neuronal injury was evaluated by cell counting after immunostaining experiments, lactate dehydrogenase release and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction. The involvement of the immunophilin FK506 binding protein 12 kDa was explored using an anti-FK506 binding protein 12 kDa antibody, (3-3-pyridyl)-1-propyl(2 s)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidine carboxylate and rapamycin. Extracellular glutamate and glutamate uptake were respectively measured by high performance liquid chromatography and l-[3H]glutamate incorporation. RESULTS: When added during either oxygen-glucose deprivation or reoxygenation, FK506 (50-500 pM) offered significant neuroprotection. During oxygen-glucose deprivation, it was able to reverse the oxygen-glucose deprivation-induced increase in extracellular glutamate and decrease in glutamate uptake and this effect was reversed in the presence of threo-3-methyl glutamate, a specific inhibitor of glutamate transporter-1. Blocking FK506 binding protein 12 kDa inhibited the neuroprotection induced by tacrolimus added during either oxygen-glucose deprivation or reoxygenation. Tacrolimus-induced neuroprotection was also reversed in the presence of rapamycin, an immunosuppressant FK506 binding protein 12 kDa ligand devoid of neuroprotective properties and (3-3-pyridyl)-1-propyl(2 s)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidine carboxylate, a non-immunosuppressant ligand of FK506 binding protein 12 kDa, exerteing neuroprotective effects. CONCLUSION: The beneficial effects of tacrolimus during in vitro ischemia/reperfusion seem to indicate the restoration of a glutamate transporter-1-mediated activity and could be mediated by a FK506 binding protein 12 kDa pathway.


Assuntos
Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Traumatismo por Reperfusão/tratamento farmacológico , Proteínas de Ligação a Tacrolimo/efeitos dos fármacos , Tacrolimo/farmacologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/patologia , Células Cultivadas , Córtex Cerebral/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Glucose/deficiência , Ácido Glutâmico/metabolismo , Imuno-Histoquímica , Técnicas In Vitro , Neurônios/patologia , Ratos , Ratos Wistar , Proteínas de Ligação a Tacrolimo/metabolismo
16.
Neurochem Int ; 46(4): 337-46, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15707698

RESUMO

This study described the involvement of short-term PKA, PKC or PI3K phosphorylation-mediated processes in the regulation of activity and trafficking of the excitatory amino acid transporters EAAC1, GLAST and GLT-1 endogenously expressed in neuron-enriched cultures. Glutamate uptake was dose-dependently decreased by inhibitors of protein kinase A (PKA), [N-[2-(p-bromocinnamylamino)-ethyl]-5-(isoquinolinesulfonamide)] (H89) or phosphatidylinositol 3-kinase (PI3K) (wortmannin), but not altered after protein kinase C (PKC) inhibition (staurosporine) or activation phorbol-12-myristate-13-acetate (PMA). Biotinylation and immunoblotting results (% of controls) showed that EAAC1 membrane expression was significantly decreased by H89 (71.9+/-4.7%) and wortmannin (63.3+/-20.0%) and increased by PMA (137.7+/-15.5%). H89 and PMA induced a significant decrease of the cell surface fraction of GLAST (54.0+/-34.1% and 73.3+/-14.3%, respectively) whereas wortmannin significantly increased this fraction (119.8+/-9.3%). After treatment with H89, the GLT-1 membrane level showed a two-fold increase (179.4+/-19.7%). Conversely, PMA and wortmannin induced a significant decrease of the cell surface expression of GLT-1 (49.0+/-15.4% and 40.7+/-33.7%, respectively). Confocal microscopy revealed a wortmannin-induced clustering of EAAC1 in the intracellular compartment. These data suggest that trafficking of glutamate transporters can be differentially regulated by PKA-, PKC- and PI3K-dependent signaling pathways and could therefore control total glutamate uptake activity. These processes may represent rapid adaptive responses to changes in the cellular environment, which significantly contribute to regulation of EAA transmission and further prevent possible excitotoxic events.


Assuntos
Proteínas de Transporte/metabolismo , Membrana Celular/metabolismo , Sistema Nervoso Central/metabolismo , Ácido Glutâmico/metabolismo , Neurônios/metabolismo , Proteínas Quinases/metabolismo , Sistema X-AG de Transporte de Aminoácidos/metabolismo , Animais , Proteínas de Transporte/efeitos dos fármacos , Compartimento Celular/efeitos dos fármacos , Compartimento Celular/fisiologia , Membrana Celular/efeitos dos fármacos , Células Cultivadas , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Citoplasma/efeitos dos fármacos , Citoplasma/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Transportador 1 de Aminoácido Excitatório , Transportador 2 de Aminoácido Excitatório/metabolismo , Transportador 3 de Aminoácido Excitatório , Proteínas de Transporte de Glutamato da Membrana Plasmática , Neurônios/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Fosforilação/efeitos dos fármacos , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/metabolismo , Transporte Proteico/efeitos dos fármacos , Transporte Proteico/fisiologia , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Simportadores/metabolismo
17.
Eur J Neurosci ; 20(5): 1255-66, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15341597

RESUMO

There is growing experimental evidence for the implication of glutamate-mediated mechanisms both in the pathophysiology of Parkinson's disease and in the development of dyskinesias with long-term administration of L-3,4-dihydroxyphenylalanine (L-DOPA). However, the impact of this treatment on glutamate transmission in the basal ganglia has been poorly investigated. In this study, we examined the effects of 6-hydroxydopamine-induced lesion of nigral dopamine neurons with or without subsequent chronic L-DOPA treatment on several parameters of glutamate system function in the rat striatum and substantia nigra pars reticulata. All the lesioned animals treated with L-DOPA developed severe dyskinesias. Extracellular glutamate levels, measured by microdialysis in freely moving conditions, and gene expression of the glial glutamate transporter GLT1, assessed by in situ hybridization, were unaffected by dopamine lesion or L-DOPA treatment alone, but were both markedly increased on the lesion side of rats with subsequent L-DOPA treatment. No change in the expression of the vesicular glutamate transporters vGluT1 and vGluT2 was measured in striatum. These data show that chronic L-DOPA treatment leading to dyskinesias increases basal levels of glutamate function in basal ganglia. The L-DOPA-induced overexpression of GLT1 may represent a compensatory mechanism involving astrocytes to limit glutamate overactivity and subsequent toxic processes.


Assuntos
Gânglios da Base/efeitos dos fármacos , Transportador 2 de Aminoácido Excitatório/biossíntese , Líquido Extracelular/metabolismo , Ácido Glutâmico/biossíntese , Levodopa/administração & dosagem , Doença de Parkinson/tratamento farmacológico , Animais , Gânglios da Base/metabolismo , Esquema de Medicação , Líquido Extracelular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Masculino , Doença de Parkinson/metabolismo , Ratos , Ratos Wistar
19.
Neurochem Int ; 40(7): 661-71, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11900862

RESUMO

The expression and activity of glutamate transporters (EAAC1, GLAST and GLT1) were examined during the development of cortical neuron-enriched cultures. Protein content and mitochondrial respiration both increased during the first 7 days, later stabilized and decreased from DIV14. Glutamate transport and extracellular concentration were relatively constant from DIV3 to 18. The kinetic parameters of glutamate transport were at DIV7: K(m)=19+/-3 microM and V(max)=1068+/-83 pmol/mg protein/min and at DIV14: K(m)=40.8+/-9.3 microM and V(max)=1060+/-235 pmol/mg protein/min. The shift in K(m) towards higher values suggest a more important participation of GLAST after DIV14. At DIV7 and 14, glutamate transport was poorly sensitive to dihydrokaïnate (DHK) suggesting a weak participation of GLT1 in glutamate transport. Western blot experiments and immunocytochemistry showed that EAAC1 was expressed by neurons whatever the stage of the culture. GLAST was found in astrocytes as soon as DIV3 and labeling increased during the development of the culture. There was little neuronal GLT1 immunoreactivity at DIV7, only detected by immunocytochemistry. From DIV10 to 18, an increasing astrocytic expression of GLT1 was observed, also detected by Western blotting. These results show that: (1) glutamate uptake remains stable all along the development of the cultures although the pattern of expression of the different transporters is changing, suggesting that glutamate transport is highly regulated; (2) neuronal EAAC1 may play a critical role during the early stages of the culture when it is expressed alone; and (3) the developmental expression pattern of glutamate transporters in cortical neuron-enriched cultures is quite similar to that observed in vivo during early postnatal development.


Assuntos
Sistema X-AG de Transporte de Aminoácidos/genética , Córtex Cerebral/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Sequência de Aminoácidos , Sistema X-AG de Transporte de Aminoácidos/metabolismo , Animais , Western Blotting , Células Cultivadas , Córtex Cerebral/citologia , Imuno-Histoquímica , Dados de Sequência Molecular , Ratos
20.
Rev Med Interne ; 22(9): 854-66, 2001 Sep.
Artigo em Francês | MEDLINE | ID: mdl-11599187

RESUMO

PURPOSE: Acquired haemophilia is a rare disease, occurring most frequently in elderly patients, caused by the development of autoantibodies against factor VIII. CURRENT KNOWLEDGE AND KEY POINTS: The disease is characterised by spontaneous haemorrhagic complications which can be fatal in 15-20% of the patients. However spontaneous remission is possible and in fact natural evolution and aetiology are still partly unknown. Acquired haemophilia may arise in association with auto-immune diseases, lymphoproliferative malignancy, pregnancy and also as a drug reaction. The aims of the treatment are first to treat the bleeding which is the most common cause of morbidity and mortality, and second to eliminate the inhibitor by immunosuppression. However no consensus exists for these two parts of the treatment. Bleeding may be controlled by prothrombin complex concentrates, recombinant factor VIIa or porcine factor VIII. The inhibitor is abolished in up 70% of patients using prednisone and cyclophosphamide. Other combinations of prednisone with azathioprine or with cyclophosphamide and vincristine or the use of high-dose immunoglobulin or double-filtration plasmapheresis have also proven effective in some patients. FUTURE AND PROJECTS: The rare occurrence of the disease, the associated with various diseases, and lack of consensus about treatment, require multicentric prospective studies.


Assuntos
Hemofilia A , Idoso , Autoanticorpos/imunologia , Doenças Autoimunes/complicações , Fator VII/uso terapêutico , Fator VIII/administração & dosagem , Fator VIII/imunologia , Feminino , Hemofilia A/diagnóstico , Hemofilia A/etiologia , Hemofilia A/imunologia , Hemofilia A/terapia , Hemorragia/etiologia , Hemorragia/terapia , Humanos , Terapia de Imunossupressão , Imunossupressores/uso terapêutico , Transtornos Linfoproliferativos/complicações , Masculino , Pessoa de Meia-Idade , Plasmaferese , Gravidez , Protrombina/uso terapêutico
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