RESUMO
Traumatic brain injury (TBI) constitutes a major health problem worldwide and is a leading cause of death and disability in individuals, contributing to devastating socioeconomic consequences. Despite numerous promising pharmacological strategies reported as neuroprotective in preclinical studies, the translation to clinical trials always failed, albeit the great diversity of therapeutic targets evaluated. In this review, first, we described epidemiologic features, causes, and primary and secondary injuries of TBI. Second, we outlined the current literature on animal models of TBI, and we described their goals, their advantages and disadvantages according to the species used, the type of injury induced, and their clinical relevance. Third, we defined the concept of neuroprotection and discussed its evolution. We also identified the reasons that might explain the failure of clinical translation. Then, we reviewed post-TBI neuroprotective treatments with a focus on the following pleiotropic drugs, considered "low hanging fruit" with high probability of success: glitazones, glibenclamide, statins, erythropoietin, and progesterone, that were largely tested and demonstrated efficient in preclinical models of TBI. Finally, our review stresses the need to establish a close cooperation between basic researchers and clinicians to ensure the best clinical translation for neuroprotective strategies for TBI.
Assuntos
Lesões Encefálicas Traumáticas/tratamento farmacológico , Lesões Encefálicas Traumáticas/fisiopatologia , Neuroproteção/fisiologia , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Fatores Etários , Animais , Ensaios Clínicos como Assunto , Modelos Animais de Doenças , Avaliação Pré-Clínica de MedicamentosRESUMO
BACKGROUND: As all anticoagulants, apixaban exposes to a bleeding risk, thus an effective way to reverse its effects is needed. Objectives were to study efficacy and safety of recombinant activated factor VII (rFVIIa), prothrombin complex concentrate (PCC), and fibrinogen concentrate (Fib) to reverse apixaban in a rabbit model of bleeding and thrombosis. METHODS: After a dose-ranging study to assess the minimal amount of apixaban increasing bleeding, 63 anaesthetized rabbits were randomized into 5 groups: control (saline), apixaban (apixaban and saline), rFVIIa (apixaban and rFVIIa), PCC (apixaban and PCC) and fibrinogen (apixaban and Fib). The Folts model was applied: a stenosis and an injury were carried out on the carotid artery, inducing thrombosis detected as cyclic flow reductions (CFRs) within 20 min. A number of parameters were recorded through ear immersion bleeding time (BT), clotting times (CT), thrombelastography, and thrombin generation time (TGT). Ultimately, a hepatosplenic section was performed to evaluate as primary endpoint the blood loss in 15 min. RESULTS: Apixaban increased blood loss (11.6 ± 3 g vs. 8.3 ± 3 g for control, p < 0.0003), lengthened BT, the prothrombin time (PT), thrombelastographic CT and decreased thrombin generation. Only rFVIIa reduced BT yet failed to improve blood loss. PCC and rFVIIa both shortened the PT, CT in thrombelastographic, and lag time in TGT. Fib improved clot firmness, enhanced thrombin generation but increased bleeding. Regarding safety, neither rFVIIa, PCC, nor Fib increased CFRs. CONCLUSION: rFVIIa, PCC, and Fib failed to reverse apixaban-induced bleeding. They only improved several laboratory parameters.
Assuntos
Fatores de Coagulação Sanguínea/uso terapêutico , Fator VIIa/uso terapêutico , Fibrinogênio/uso terapêutico , Hemorragia/tratamento farmacológico , Pirazóis/toxicidade , Piridonas/toxicidade , Trombose/tratamento farmacológico , Animais , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Hemorragia/induzido quimicamente , Hemorragia/fisiopatologia , Masculino , Pirazóis/antagonistas & inibidores , Piridonas/antagonistas & inibidores , Coelhos , Proteínas Recombinantes/uso terapêutico , Trombose/induzido quimicamente , Trombose/fisiopatologiaRESUMO
BACKGROUND: As a potent anticoagulant agent, rivaroxaban exposes a risk of bleeding. An effective way to reverse its effects is needed. Objectives were to study efficacy and safety of recombinant activated factor VII (rFVIIa) and prothrombin complex concentrate (PCC) to reverse the anticoagulant effect of an overdose of rivaroxaban in a rabbit model of bleeding and thrombosis. METHODS: First, a dose-ranging study assessed the minimal rivaroxaban dose that increased bleeding. Then, 48 anesthetized and ventilated rabbits were randomized into four groups: control (saline), rivaroxaban (rivaroxaban and saline), rFVIIa (rivaroxaban and rFVIIa), and PCC (rivaroxaban and PCC). The Folts model was applied: a stenosis and an injury were carried out on the carotid artery, inducing thrombosis, detected as cyclic flow reductions, which were recorded over 20 min. Then the following were measured: ear immersion bleeding time, clotting times, anti-Xa activity, thrombelastometric parameters, and thrombin generation test. Ultimately, a hepatosplenic section was performed and the total amount of blood loss after 15 min was evaluated as primary endpoint. RESULTS: Rivaroxaban increased blood loss (17 g [8-32] vs. 7 g [5-18] for control (median [range]), P = 0.0004), ear bleeding time, clotting times, thrombelastographic clotting time, and decreased thrombin generation. In contrast, rFVIIa decreased ear bleeding time (92 s [65-115] vs. 140 s [75-190], P < 0.02), but without efficacy on blood loss. PCC and rFVIIa decreased activated partial thromboplastin time as well as thrombelastographic clotting time. Regarding safety, neither rFVIIa nor PCC increased cyclic flow reductions. CONCLUSION: rFVIIa and PCC partially improved laboratory parameters, but did not reverse rivaroxaban induced-bleeding.
Assuntos
Anticoagulantes/antagonistas & inibidores , Fator VIIa/uso terapêutico , Morfolinas/antagonistas & inibidores , Protrombina/uso terapêutico , Tiofenos/antagonistas & inibidores , Anestesia , Animais , Anticoagulantes/farmacologia , Tempo de Sangramento , Testes de Coagulação Sanguínea , Pressão Sanguínea/efeitos dos fármacos , Temperatura Corporal/efeitos dos fármacos , Relação Dose-Resposta a Droga , Fator VIIa/administração & dosagem , Hemorragia/sangue , Fígado/irrigação sanguínea , Masculino , Monitorização Fisiológica , Morfolinas/farmacologia , Protrombina/administração & dosagem , Coelhos , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/uso terapêutico , Respiração Artificial , Rivaroxabana , Baço/irrigação sanguínea , Tiofenos/farmacologia , Tromboelastografia , Trombina/biossíntese , Trombose/sangue , Trombose/tratamento farmacológicoRESUMO
BACKGROUND: Traumatic brain injury models are widely studied, especially through gene expression, either to further understand implied biological mechanisms or to assess the efficiency of potential therapies. A large number of biological pathways are affected in brain trauma models, whose elucidation might greatly benefit from transcriptomic studies. However the suitability of reference genes needed for quantitative RT-PCR experiments is missing for these models. RESULTS: We have compared five potential reference genes as well as total cDNA level monitored using Oligreen reagent in order to determine the best normalizing factors for quantitative RT-PCR expression studies in the early phase (0-48 h post-trauma (PT)) of a murine model of diffuse brain injury. The levels of 18S rRNA, and of transcripts of beta-actin, glyceraldehyde-3P-dehydrogenase (GAPDH), beta-microtubulin and S100beta were determined in the injured brain region of traumatized mice sacrificed at 30 min, 3 h, 6 h, 12 h, 24 h and 48 h post-trauma. The stability of the reference genes candidates and of total cDNA was evaluated by three different methods, leading to the following rankings as normalization factors, from the most suitable to the less: by using geNorm VBA applet, we obtained the following sequence: cDNA(Oligreen); GAPDH > 18S rRNA > S100beta > beta-microtubulin > beta-actin; by using NormFinder Excel Spreadsheet, we obtained the following sequence: GAPDH > cDNA(Oligreen) > S100beta > 18S rRNA > beta-actin > beta-microtubulin; by using a Confidence-Interval calculation, we obtained the following sequence: cDNA(Oligreen) > 18S rRNA; GAPDH > S100beta > beta-microtubulin > beta-actin. CONCLUSION: This work suggests that Oligreen cDNA measurements, 18S rRNA and GAPDH or a combination of them may be used to efficiently normalize qRT-PCR gene expression in mouse brain trauma injury, and that beta-actin and beta-microtubulin should be avoided. The potential of total cDNA as measured by Oligreen as a first-intention normalizing factor with a broad field of applications is highlighted. Pros and cons of the three methods of normalization factors selection are discussed. A generic time- and cost-effective procedure for normalization factor validation is proposed.
Assuntos
Lesões Encefálicas/genética , Perfilação da Expressão Gênica/normas , Reação em Cadeia da Polimerase Via Transcriptase Reversa/normas , Actinas/genética , Animais , DNA Complementar/análise , DNA Complementar/normas , Gliceraldeído-3-Fosfato Desidrogenase (Fosforiladora)/genética , Camundongos , Modelos Animais , Fatores de Crescimento Neural/genética , RNA Ribossômico 18S/genética , Padrões de Referência , Subunidade beta da Proteína Ligante de Cálcio S100 , Proteínas S100/genética , Tubulina (Proteína)/genética , Estudos de Validação como AssuntoRESUMO
OBJECTIVE: The benefit of immune-enhancing diets (IEDs) in the intensive care unit remains controversial. Considering their complexity, the role of each component, in particular arginine (Arg), in their properties is largely unknown. The aim of this study was to determine the role of arginine in the immunomodulatory effects of an IED (Crucial) in head-injured rats. DESIGN: Thirty-four rats were randomized into five groups: AL (ad libitum), HI (head-injured), HI-STD (HI + standard enteral nutrition, EN), HI-STD-Arg (HI + standard EN + Arg in equimolar concentration to Arg in IED), and HI-IED (HI + IED). These isocaloric and isonitrogenous diets were administered over 4 days. After death, the thymus was removed and weighed. The density of CD25, CD4 and CD8 on lymphocytes from blood and from Peyer patches was evaluated. Mesenteric lymph nodes, liver and spleen were cultured for analysis of enterobacterial translocation and dissemination. MEASUREMENTS AND RESULTS: HI induced an atrophy of the thymus which was not corrected by the standard diet (HI 0.27 +/- 0.03, HI-STD 0.35 +/- 0.03 vs. AL 0.49 +/- 0.02 g; p < 0.05). However, the standard diet supplemented with arginine limited the thymic atrophy and the IED restored thymus weight. CD25 density and interleukin-2 production were increased only in the HI-STD-Arg and HI-IED groups (p < 0.05). Head injury induced enterobacterial translocation and dissemination which were blunted only in the HI-STD-Arg group (p < 0.05). CONCLUSIONS: In this rat HI model, arginine appears to be safe, contributes to a large extent to the immunomodulatory effects of the IED, and seems to limit enterobacterial translocation and dissemination more efficiently alone than in an IED.