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OBJECTIVES: Disseminated fibrin-rich microthrombi have been reported in patients who died from COVID-19. Our objective is to determine whether the fibrin clot structure and function differ between critically ill patients with or without COVID-19 and to correlate the structure with clinical coagulation biomarkers. DESIGN: A cross-sectional observational study. Platelet poor plasma was used to analyze fibrin clot structure; the functional implications were determined by quantifying clot turbidity and porosity. SETTING: ICU at an academic medical center and an academic laboratory. PATIENTS: Patients admitted from July 1 to August 1, 2020, to the ICU with severe acute respiratory syndrome coronavirus 2 infection confirmed by reverse transcription-polymerase chain reaction or patients admitted to the ICU with sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Blood was collected from 36 patients including 26 ICU patients with COVID-19 and 10 ICU patients with sepsis but without COVID-19 at a median of 11 days after ICU admission (interquartile range, 3-16). The cohorts were similar in age, gender, body mass index, comorbidities, Sequential Organ Failure Assessment (SOFA) score, and mortality. More patients with COVID-19 (100% vs 70%; p = 0.003) required anticoagulation. Ex vivo fibrin clots formed from patients with COVID-19 appeared to be denser and to have smaller pores than those from patients with sepsis but without COVID-19 (percent area of fluorescent fibrin 48.1% [SD, 16%] vs 24.9% [SD, 18.8%]; p = 0.049). The turbidity and flow-through assays corroborated these data; fibrin clots had a higher maximum turbidity in patients with COVID-19 compared with patients without COVID-19 (0.168 vs 0.089 OD units; p = 0.003), and it took longer for buffer to flow through these clots (216 vs 103 min; p = 0.003). In patients with COVID-19, d-dimer levels were positively correlated with percent area of fluorescent fibrin (ρ = 0.714, p = 0.047). Denser clots (assessed by turbidity and thromboelastography) and higher SOFA scores were independently associated with delayed clot lysis. CONCLUSIONS: We found aberrant fibrin clot structure and function in critically ill patients with COVID-19. These findings may contribute to the poor outcomes observed in COVID-19 patients with widespread fibrin deposition.
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COVID-19 , Sepsis , Tromboembolia , Trombosis , Enfermedad Crítica , Estudios Transversales , Fibrina , Fibrinólisis , HumanosRESUMEN
Sucrose consumption impairs behavioral and cognitive functions that correlate with decreased neurogenesis in animal models. When consumed during early adolescence, this disaccharide promotes anxious and depressive behaviors, along with a reduction in the generation of new neurons in the dentate gyrus of the hippocampus. Data concerning sucrose consumption during late adolescence are lacking, and the effect of sucrose intake on the ventral dentate gyrus of the hippocampus (which modulates anxiety and depression) remains elusive. Here, we tested whether sucrose intake during late adolescence causes anxiety or impaired neurogenesis in the ventral dentate gyrus. Rats did not display anxiety-like behaviors neither at the light−dark box test nor at the open field exploration. However, there was a significant increase in proliferative cells in the subgranular zone of the ventral dentate gyrus in rats exposed to sucrose (p < 0.05). This increased proliferation corresponded to neural stem cells (Radial Type 1 cells) in the group exposed to sucrose until adulthood but was not present in rats exposed to sucrose only during late adolescence. Remarkably, the phosphorylation of ERK1/2 kinases was increased in the hippocampi of rats exposed to sucrose only during late adolescence, suggesting that the increased proliferation in this group could be mediated by the MAPK pathway. On the other hand, although no differences were found in the number of immature granular neurons, we observed more immature granular neurons with impaired dendritic orientation in both groups exposed to sucrose. Finally, GAD65/67 and BCL2 levels did not change between groups, suggesting an unaltered hippocampal GABAergic system and similar apoptosis, respectively. This information provides the first piece of evidence of how sucrose intake, starting in late adolescence, impacts ventral dentate gyrus neurogenesis and contributes to a better understanding of the effects of this carbohydrate on the brain at postnatal stages.
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Giro Dentado , Células-Madre Neurales , Ratas , Animales , Giro Dentado/metabolismo , Sacarosa/metabolismo , Neurogénesis/fisiología , Células-Madre Neurales/metabolismo , AnsiedadRESUMEN
Cathepsin B is one of the major lysosomal cysteine proteases involved in neuronal protein catabolism. This cathepsin is released after traumatic injury and increases neuronal death; however, release of cystatin C, a cathepsin inhibitor, appears to be a self-protective brain response. Here we describe the effect of cystatin C intracerebroventricular administration in rats prior to inducing a traumatic brain injury. We observed that cystatin C injection caused a dual response in post-traumatic brain injury recovery: higher doses (350 fmoles) increased bleeding and mortality, whereas lower doses (3.5 to 35 fmoles) decreased bleeding, neuronal damage and mortality. We also analyzed the expression of cathepsin B and cystatin C in the brains of control rats and of rats after a traumatic brain injury. Cathepsin B was detected in the brain stem, cerebellum, hippocampus and cerebral cortex of control rats. Cystatin C was localized to the choroid plexus, brain stem and cerebellum of control rats. Twenty-four hours after traumatic brain injury, we observed changes in both the expression and localization of both proteins in the cerebral cortex, hippocampus and brain stem. An early increase and intralysosomal expression of cystatin C after brain injury was associated with reduced neuronal damage.
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Lesiones Encefálicas/mortalidad , Lesiones Encefálicas/patología , Catepsina B/biosíntesis , Cistatina C/farmacología , Animales , Apoptosis , Tronco Encefálico/metabolismo , Catepsina B/metabolismo , Cerebelo/metabolismo , Corteza Cerebral/metabolismo , Plexo Coroideo/metabolismo , Cistatina C/biosíntesis , Hemorragia/inducido químicamente , Hipocampo/metabolismo , Masculino , Neuronas/patología , Ratas , Ratas WistarRESUMEN
Normally, von Willebrand factor (VWF) remains inactive unless its A1A2 domains undergo a shear stress-triggered conformational change. We demonstrated the capacity of a recombinant A2 domain of VWF to bind and to affect fibrin formation, altering the fibrin clot structure. The data indicated that VWF contains an additional binding site for fibrin in the A2 domain that plays a role in the incorporation of VWF to the polymerizing fibrin. This study is to examine the hypothesis that active plasma VWF directly influence fibrin polymerization and the structure of fibrin clots. The study used healthy and type 3 von Willebrand disease (VWD) plasma, purified plasma VWF, fibrin polymerization assays, confocal microscopy and scanning electron microscopy. The exposed A2 domain in active VWF harbors additional binding sites for fibrinogen, and significantly potentiates fibrin formation (Pâ<â0.02). Antibody against the A2 domain of VWF significantly decreased the initial rate of change of fibrin formation (Pâ<â0.002). Clot analyses revealed a significant difference in porosity between normal and type 3 VWD plasma (Pâ<â0.008), further supported by scanning electron microscopy, which demonstrated thicker fibrin fibers in the presence of plasma VWF (Pâ<â0.0003). Confocal immunofluorescence microscopy showed punctate VWF staining along fibrin fibrils, providing visual evidence of the integration of plasma VWF into the fibrin matrix. The study with type 3 VWD plasma supports the hypothesis that plasma VWF directly influences fibrin polymerization and clot structure. In addition, a conformational change in the A1A2 domains exposes a hidden fibrin(ogen) binding site, indicating that plasma VWF determines the fibrin clot structure.
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Fibrina , Factor de von Willebrand , Factor de von Willebrand/metabolismo , Humanos , Fibrina/metabolismo , Fibrina/ultraestructura , Enfermedad de von Willebrand Tipo 3/sangre , Sitios de Unión , Microscopía Electrónica de Rastreo/métodosRESUMEN
Traumatic brain injury (TBI) represents a public health issue with a high mortality rate and severe neurological and psychiatric consequences. Mood and anxiety disorders are some of the most frequently reported. Primary and secondary damage can cause a loss of neurons and glial cells, leading to dysfunction of neuronal circuits, which can induce imbalances in many neurotransmitter systems. Monoaminergic systems, especially the dopaminergic system, are some of the most involved in the pathogenesis of neuropsychiatric and cognitive symptoms after TBI. In this work, we summarize the studies carried out in patients who have suffered TBI and describe alterations in the dopaminergic system, highlighting (1) dysfunction of the dopaminergic neuronal circuits caused by TBI, where modifications are shown in the dopamine transporter (DAT) and alterations in the expression of dopamine receptor 2 (D2R) in brain areas with dopaminergic innervation, thus establishing a hypodopaminergic state and (2) variations in the concentration of dopamine and its metabolites in biological fluids of post-TBI patients, such as elevated dopamine (DA) and alterations in homovanillic acid (HVA). On the other hand, we show a large number of reports of alterations in the dopaminergic system after a TBI in animal models, in which modifications in the levels of DA, DAT, and HVA have been reported, as well as alterations in the expression of tyrosine hydroxylase (TH). We also describe the biological pathways, neuronal circuits, and molecular mechanisms potentially involved in mood and anxiety disorders that occur after TBI and are associated with alterations of the dopaminergic system in clinical studies and animal models. We describe the changes that occur in the clinical picture of post-TBI patients, such as alterations in mood and anxiety associated with DAT activity in the striatum, the relationship between post-TBI major depressive disorders (MDD) with lower availability of the DA receptors D2R and D3R in the caudate and thalamus, as well as a decrease in the volume of the substantia nigra (SN) associated with anxiety symptoms. With these findings, we discuss the possible relationship between the disorders caused by alterations in the dopaminergic system in patients with TBI.
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BACKGROUND: Sepsis can lead to coagulopathy and microvascular thrombosis. Prior studies, including ours, reported an increased level of extracellular vimentin in blood derived from septic patients. Moreover, we identified the contribution of extracellular vimentin to fibrin formation and to the fibrin clot structure ex vivo in plasma from septic patients. Here, we tested the status of plasma vimentin and its impact on fibrin clots using our recently described swine model of methicillin-resistant Staphylococcus aureus (MRSA) sepsis-induced coagulopathy. RESULTS: We employed ELISA, size-exclusion chromatography, vimentin antibodies, confocal microscopy, and turbidity assays on piglet plasma obtained at pre- and post-MRSA inoculation. Plasma vimentin level at 70 h post-MRSA inoculation was on average twofold higher compared to pre-infection (0 h) level in the same animal. Anti-vimentin antibody effectively reduced fibrin formation ex vivo and increased porosity in the fibrin clot structure generated from septic piglet plasma. In contrast to plasma at 0 h, the size-exclusion chromatography revealed that phosphorylated vimentin was in-complex with fibrinogen in septic piglet plasma. CONCLUSIONS: Thus, our swine model of sepsis-induced coagulopathy, reproduced increased extracellular circulating vimentin and subsequent potentiation of fibrin formation, often observed in septic patient. These outcomes validate the use of large animal models to investigate the dysregulated host immune response to infection leading to coagulopathy, and to develop new therapies for sepsis-induced disseminated microvascular thrombosis.
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The endocannabinoid system is a component of the neuroprotective mechanisms that an organism displays after traumatic brain injury (TBI). A diurnal variation in several components of this system has been reported. This variation may influence the recovery and survival rate after TBI. We have previously reported that the recovery and survival rate of rats is higher if TBI occurs at 1:00 than at 13:00. This could be explained by a diurnal variation of the endocannabinoid system. Here, we describe the effects of anandamide administration in rats prior to the induction of TBI at two different times of the day: 1:00 and 13:00. We found that anandamide reduced the neurological damage at both times. Nevertheless, its effects on bleeding, survival, food intake, and body weight were dependent on the time of TBI. In addition, we analyzed the diurnal variation of the expression of the cannabinoid receptors CB1R and CB2R in the cerebral cortex of both control rats and rats subjected to TBI. We found that CB1R protein was expressed more during the day, whereas its mRNA level was higher during the night. We did not find a diurnal variation for the CB2R. In addition, we also found that TBI increased CB1R and CB2R in the contralateral hemisphere and disrupted the CB1R diurnal cycle.
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Ácidos Araquidónicos/uso terapéutico , Lesiones Encefálicas/terapia , Antagonistas de Receptores de Cannabinoides/uso terapéutico , Endocannabinoides/uso terapéutico , Fármacos Neuroprotectores/uso terapéutico , Alcamidas Poliinsaturadas/uso terapéutico , Animales , Lesiones Encefálicas/metabolismo , Lesiones Encefálicas/mortalidad , Corteza Cerebral/metabolismo , Ritmo Circadiano/fisiología , Modelos Animales de Enfermedad , Hemorragia , Masculino , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Receptor Cannabinoide CB1/genética , Receptor Cannabinoide CB1/metabolismo , Receptor Cannabinoide CB2/genética , Receptor Cannabinoide CB2/metabolismo , Tasa de SupervivenciaRESUMEN
INTRODUCTION: Thrombosis is frequently manifested in critically ill patients with systemic inflammation, including sepsis and COVID-19. The coagulopathy in systemic inflammation is often associated with increased levels of fibrinogen and D-dimer. Because elevated levels of vimentin have been detected in sepsis, we sought to investigate the relationship between vimentin and the increased fibrin formation potential observed in these patients. MATERIALS AND METHODS: This hypothesis was examined by using recombinant human vimentin, anti-vimentin antibodies, plasma derived from healthy and critically ill patients, confocal microscopy, co-immunoprecipitation assays, and size exclusion chromatography. RESULTS: The level of vimentin in plasma derived from critically ill subjects with systemic inflammation was on average two-fold higher than that of healthy volunteers. We determined that vimentin directly interacts with fibrinogen and enhances fibrin formation. Anti-vimentin antibody effectively blocked fibrin formation ex vivo and caused changes in the fibrin structure in plasma. Additionally, confocal imaging demonstrated plasma vimentin enmeshed in the fibrin fibrils. Size exclusion chromatography column and co-immunoprecipitation assays demonstrated a direct interaction between extracellular vimentin and fibrinogen in plasma from critically ill patients but not in healthy plasma. CONCLUSIONS: The results describe that extracellular vimentin engages fibrinogen in fibrin formation. In addition, the data suggest that elevated levels of an apparent aberrant extracellular vimentin potentiate fibrin clot formation in critically ill patients with systemic inflammation; consistent with the notion that plasma vimentin contributes to the pathogenesis of thrombosis.
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COVID-19 , Hemostáticos , Trombosis , Humanos , COVID-19/complicaciones , Enfermedad Crítica , Fibrina , Fibrinógeno/química , Inflamación/complicaciones , Trombosis/etiología , Vimentina/metabolismo , Espacio Extracelular/metabolismoRESUMEN
Sepsis-induced coagulopathy leading to disseminated microvascular thrombosis is associated with high mortality and has no existing therapy. Despite the high prevalence of Gram-positive bacterial sepsis, especially methicillin-resistant Staphylococcus aureus (MRSA), there is a paucity of published Gram-positive pediatric sepsis models. Large animal models replicating sepsis-induced coagulopathy are needed to test new therapeutics before human clinical trials. HYPOTHESIS: Our objective is to develop a pediatric sepsis-induced coagulopathy swine model that last 70 hours. METHODS AND MODELS: Ten 3 weeks old piglets, implanted with telemetry devices for continuous hemodynamic monitoring, were IV injected with MRSA (n = 6) (USA300, Texas Children's Hospital 1516 strain) at 1 × 109 colony forming units/kg or saline (n = 4). Fluid resuscitation was given for heart rate greater than 50% or mean arterial blood pressure less than 30% from baseline. Acetaminophen and dextrose were provided as indicated. Point-of-care complete blood count, prothrombin time (PT), activated thromboplastin time, d-dimer, fibrinogen, and specialized coagulation assays were performed at pre- and post-injection, at 0, 24, 48, 60, and 70 hours. Piglets were euthanized and necropsies performed. RESULTS: Compared with the saline treated piglets (control), the septic piglets within 24 hours had significantly lower neurologic and respiratory scores. Over time, PT, d-dimer, and fibrinogen increased, while platelet counts and activities of factors V, VII, protein C, antithrombin, and a disintegrin and metalloproteinase with thrombospondin-1 motifs (13th member of the family) (ADAMTS-13) decreased significantly in septic piglets compared with control. Histopathologic examination showed minor focal organ injuries including microvascular thrombi and necrosis in the kidney and liver of septic piglets. INTERPRETATIONS AND CONCLUSIONS: We established a 70-hour swine model of MRSA sepsis-induced coagulopathy with signs of consumptive coagulopathy, disseminated microvascular thrombosis, and early organ injuries with histological minor focal organ injuries. This model is clinically relevant to pediatric sepsis and can be used to study dysregulated host immune response and coagulopathy to infection, identify potential early biomarkers, and to test new therapeutics.
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The endocannabinoid system is found in tissues that regulate the glycemia, including adipose tissue, muscle, and pancreatic islets. Diet-induced metabolic syndrome changes the expression of the CB receptors in muscle, adipose tissue, and liver. However, it is poorly understood whether metabolic syndrome (MetS) affects the expression of CB receptors in pancreatic ß cells. We analyzed the expression of CB receptors in pancreatic ß cells under chronic high-sucrose diet (HSD)-induced MetS. Wistar rats fed an HSD as a model of MetS were used to investigate changes in cannabinoid receptors. After 8 weeks of treatment, we evaluated the appearance of the following MetS biomarkers: glucose intolerance, hyperinsulinemia, insulin resistance, hypertriglyceridemia, and an increase in visceral adiposity. To determine the presence of CB1 and CB2 receptors in pancreatic ß cells, immunofluorescence of primary cell cultures and pancreatic sections was performed. For whole-islet quantification of membrane-bound CB1 and CB2 receptors, western-blotting following differential centrifugation was conducted. Our results revealed that an HSD treatment closely mimics the alterations seen in MetS. We observed that in primary cell culture, CB1 and CB2 receptors were expressed at a higher level in pancreatic ß cells compared with non-ß cells. MetS resulted in a reduction of CB1 in the islet, whereas abundant CB2 was observed after the treatment. CB1 and CB2 receptors are differentially expressed in pancreatic ß cells during MetS development.
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Células Secretoras de Insulina , Islotes Pancreáticos , Síndrome Metabólico , Animales , Síndrome Metabólico/etiología , Ratas , Ratas Wistar , Receptores de CannabinoidesRESUMEN
Systemic inflammation can lead to coagulopathy and disseminated intravascular coagulation (DIC). In prior studies, the recombinant A2 domain of human von Willebrand factor (VWF; A2 protein) attenuated DIC and decreased mortality in lipopolysaccharide (LPS)-treated mice. Here, we performed studies to dissect the mechanism by which the A2 protein moderates DIC. We used confocal microscopy to analyze the fibrin clot structure in plasma from healthy humans and endotoxemic mice, turbidity assays to examine fibrin polymerization, and a murine model for LPS-induced DIC and introduced a loss-of-function mutation into the A2 protein for fibrin. The mutation of the residue E1567 located in the α2 helix of the folded A2 domain of VWF inhibited binding activity for fibrin, possibly mapping a novel region containing a putative binding site for fibrin. The A2 protein increased the initial rate of change of fibrin polymerization, intercalated into the fibrin network, and modified the resultant clot structure in vitro. Furthermore, ex vivo experiments using plasma from mice with endotoxemia treated with the A2 protein revealed an increased rate of fibrin formation and an altered clot structure as compared with plasma from nontreated sick animals. Moreover, and in contrast to the A2 mutant, the A2 protein improved survival and reduced fibrin deposition and microvascular thrombosis in mice with endotoxemia-induced DIC. Importantly, in vivo and in vitro studies indicated that the A2 protein did not affect experimental thrombosis. Thus, we provide evidence for a novel treatment to attenuate systemic inflammation-induced coagulopathy/DIC via targeting fibrin formation, without an increased risk for bleeding.
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Coagulación Intravascular Diseminada , Trombosis , Animales , Coagulación Intravascular Diseminada/tratamiento farmacológico , Coagulación Intravascular Diseminada/etiología , Fibrina , Inflamación/tratamiento farmacológico , Ratones , Trombosis/tratamiento farmacológico , Trombosis/etiología , Factor de von WillebrandRESUMEN
Von Willebrand factor (VWF), an exceptionally large multimeric plasma glycoprotein, functions to initiate coagulation by agglutinating platelets in the blood stream to sites of vascular injury. This primary hemostatic function is perturbed in type 2 dysfunctional subtypes of von Willebrand disease (VWD) by mutations that alter the structure and function of the platelet GPIbα adhesive VWF A1 domains. The resulting amino acid substitutions cause local disorder and misfold the native structure of the isolated platelet GPIbα-adhesive A1 domain of VWF in both gain-of-function (type 2B) and loss-of-function (type 2M) phenotypes. These structural effects have not been explicitly observed in A1 domains of VWF multimers native to blood plasma. New mass spectrometry strategies are applied to resolve the structural effects of 2B and 2M mutations in VWF to verify the presence of A1 domain structural disorder in multimeric VWF harboring type 2 VWD mutations. Limited trypsinolysis mass spectrometry (LTMS) and hydrogen-deuterium exchange mass spectrometry (HXMS) are applied to wild-type and VWD variants of the single A1, A2, and A3 domains, an A1A2A3 tridomain fragment of VWF, plasmin-cleaved dimers of VWF, multimeric recombinant VWF, and normal VWF plasma concentrates. Comparatively, these methods show that mutations known to misfold the isolated A1 domain increase the rate of trypsinolysis and the extent of hydrogen-deuterium exchange in local secondary structures of A1 within multimeric VWF. VWD mutation effects are localized to the A1 domain without appreciably affecting the structure and dynamics of other VWF domains. The intrinsic dynamics of A1 observed in recombinant fragments of VWF are conserved in plasma-derived VWF. These studies reveal that structural disorder does occur in VWD variants of the A1 domain within multimeric VWF and provides strong support for VWF misfolding as a result of some, but not all, type 2 VWD variants.
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Estructura Secundaria de Proteína/genética , Deficiencias en la Proteostasis/genética , Enfermedad de von Willebrand Tipo 2/genética , Factor de von Willebrand/genética , Sustitución de Aminoácidos , Plaquetas/química , Plaquetas/metabolismo , Regulación de la Expresión Génica/genética , Células HEK293 , Humanos , Mutación con Pérdida de Función/genética , Espectrometría de Masas , Dominios Proteicos/genética , Pliegue de Proteína , Multimerización de Proteína/genética , Deficiencias en la Proteostasis/sangre , Deficiencias en la Proteostasis/patología , Enfermedad de von Willebrand Tipo 2/sangre , Enfermedad de von Willebrand Tipo 2/patología , Factor de von Willebrand/química , Factor de von Willebrand/ultraestructuraRESUMEN
RATIONALE: One of the adaptive abilities of the brain is the generation of a strategy to optimize acquisition of information, i.e., learning. In this study, we explored the role of environmental conditions (the light-dark cycle) and of the endocannabinoid anandamide in rats to select a strategy to solve the Barnes maze (BM). OBJECTIVES: To determine the effects of manipulating the cannabinergic system on a spatial task in relation to the light-dark cycle. MATERIALS AND METHODS: Rats received an intrahippocampal or intrastriatal administration of anandamide, AM251, or their combination at two different points of the light-dark cycle (1300 and 0100 hours), and their performance in the BM was evaluated. In addition, we determined the expression of the cannabinoid 1 receptor (CB1R) in the hippocampus and striatum throughout the light-dark cycle. RESULTS: Results indicate that rats solved the BM by using a spatial strategy during the light phase and a procedural (serial) strategy during the dark phase of the cycle. CB1R expression varied in the hippocampus, being higher at 1300 hours and lower at 0100 hours, whereas its expression remained unchanged in the striatum. CONCLUSIONS: Changes in the brain, which include changes in the endocannabinoid system, prompt it to use different strategies (spatial and procedural, or others not evaluated in this study) to cope with the environmental demands. These cerebral changes are adaptive responses to the light-dark cycle.
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Ácidos Araquidónicos/farmacología , Moduladores de Receptores de Cannabinoides/farmacología , Endocannabinoides , Aprendizaje por Laberinto/efectos de los fármacos , Orientación/efectos de los fármacos , Alcamidas Poliinsaturadas/farmacología , Animales , Ácidos Araquidónicos/administración & dosificación , Western Blotting , Ritmo Circadiano/efectos de los fármacos , Oscuridad , Hipocampo/fisiología , Inmunohistoquímica , Luz , Masculino , Microinyecciones , Neostriado/fisiología , Piperidinas/administración & dosificación , Piperidinas/farmacología , Alcamidas Poliinsaturadas/administración & dosificación , Pirazoles/administración & dosificación , Pirazoles/farmacología , ARN/biosíntesis , ARN/aislamiento & purificación , Ratas , Ratas Wistar , Receptor Cannabinoide CB1/antagonistas & inhibidores , Receptor Cannabinoide CB1/biosíntesis , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
OBJECTIVE: Data from our laboratory suggest that recovery from a traumatic brain injury depends on the time of day at which it occurred. In this study, we examined whether traumatic brain injury -induced damage is related to circadian variation in N-methyl-D-aspartate receptor expression in rat cortex. RESULTS: We confirmed that traumatic brain injury recovery depended on the time of day at which the damage occurred. We also found that motor cortex N-methyl-D-aspartate receptor subunit NR1 expression exhibited diurnal variation in both control and traumatic brain injury-subjected rats. However, this rhythm is more pronounced in traumatic brain injury-subjected rats, with minimum expression in those injured during nighttime hours. These findings suggest that traumatic brain injury occurrence times should be considered in future clinical studies and when designing neuroprotective strategies for patients.
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Lesiones Traumáticas del Encéfalo/metabolismo , Lesiones Traumáticas del Encéfalo/fisiopatología , Ritmo Circadiano/fisiología , Corteza Motora/lesiones , Corteza Motora/metabolismo , Corteza Motora/fisiopatología , Receptores de N-Metil-D-Aspartato/metabolismo , Animales , Modelos Animales de Enfermedad , Masculino , Ratas , Ratas Wistar , Factores de TiempoRESUMEN
Traumatic brain injury (TBI) is a contemporary health problem and a leading cause of mortality and morbidity worldwide. Survivors of TBI frequently experience disabling long-term changes in cognition, sensorimotor function, and personality. A crucial step in understanding TBI and providing better treatment has been the use of models to mimic the event under controlled conditions. Here, we describe the known head injury models, which can be classified as whole animal (in vivo), in vitro, and mathematical models. We will also review the ways in which these models have advanced the knowledge of TBI.
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Lesiones Traumáticas del Encéfalo/fisiopatología , Lesiones Traumáticas del Encéfalo/terapia , Modelos Animales de Enfermedad , Recuperación de la Función/fisiología , Animales , Línea Celular , Cognición/fisiología , Humanos , InvestigaciónRESUMEN
Traumatic brain injury (TBI) represents a significant public health concern and has been associated with high rates of morbidity and mortality. Although several research groups have proposed the use of repetitive transcranial magnetic stimulation (rTMS) to enhance neuroprotection and recovery in patients with TBI, few studies have obtained sufficient evidence regarding its effects in this population. Therefore, we aimed to analyze the effect of intermediate-frequency rTMS (2 Hz) on behavioral and histological recovery following TBI in rats. Male Wistar rats were divided into six groups: three groups without TBI (no manipulation, movement restriction plus sham rTMS, and movement restriction plus rTMS) and three groups subjected to TBI (TBI only, TBI plus movement restriction and sham rTMS, and TBI plus movement restriction and rTMS). The movement restriction groups were included so that rTMS could be applied without anesthesia. Our results indicate that the restriction of movement and sham rTMS per se promotes recovery, as measured using a neurobehavioral scale, although rTMS was associated with faster and superior recovery. We also observed that TBI caused alterations in the CA1 and CA3 subregions of the hippocampus, which are partly restored by movement restriction and rTMS. Our findings indicated that movement restriction prevents damage caused by TBI and that intermediate-frequency rTMS promotes behavioral and histologic recovery after TBI.
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Conducta Animal , Lesiones Traumáticas del Encéfalo , Estimulación Magnética Transcraneal , Animales , Lesiones Traumáticas del Encéfalo/patología , Lesiones Traumáticas del Encéfalo/fisiopatología , Lesiones Traumáticas del Encéfalo/terapia , Masculino , Ratas , Ratas WistarRESUMEN
Many studies indicate that the hour of the day at which the onset of stroke occurs is very important in patient recovery. Furthermore, multiple studies have been conducted which show that ischemia in rats produces different magnitudes of injury depending on the hour of the day at which it was induced. Using a traumatic brain injury (TBI) model, we analyzed the effect of the time of day on the recovery of rats and obtained a higher survival rate if TBI was induced at 01:00 h as compared with TBI induced at 13:00 h. We also analyzed the effect of the protease inhibitor cystatin C (CC) on the recovery of rats from TBI and found that it increased mortality and bleeding, and that these effects were more pronounced at 13:00 h.
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Lesiones Encefálicas/tratamiento farmacológico , Ritmo Circadiano , Cistatinas/administración & dosificación , Fármacos Neuroprotectores/administración & dosificación , Recuperación de la Función/efectos de los fármacos , Análisis de Varianza , Animales , Lesiones Encefálicas/fisiopatología , Cistatina C , Modelos Animales de Enfermedad , Esquema de Medicación , Masculino , Ratas , Ratas Wistar , Índices de Gravedad del TraumaRESUMEN
It has been hypothesized that proteins modulate rapid eye movement sleep (REMS). Studies have shown an increase in the liberation of proteins in the mesencephalic reticular formation of cats during REMS. It has also been determined that protein-synthesis inhibitors diminish REMS and that protease-inhibitors increase this sleep phase. These and other studies support the importance of "di novo" protein molecules in sleep, and in particular, in REMS regulation. In this context, it is important to determine the role of endogenous proteases and their endogenous inhibitors in sleep regulation. In this study, we found that Cystatin C (CC), an endogenous protease inhibitor, diminishes wakefulness and increases REMS. We have also found an increase in CC expression after REMS deprivation and a tendency to decrease after a 2 h period of REMS rebound. We further showed that REMS deprivation increases the expression of Cathepsin H (CH), a protease inhibited by CC. These results suggest that naturally occurring protease-inhibitors enhance REMS, perhaps by facilitating the availability of proteins.
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Ritmo Circadiano/fisiología , Cistatinas/metabolismo , Sueño REM/fisiología , Animales , Anticuerpos/farmacología , Western Blotting/métodos , Ritmo Circadiano/efectos de los fármacos , Cistatina C , Cistatinas/inmunología , Cistatinas/farmacología , Inyecciones Intraventriculares/métodos , Masculino , Polisomnografía/métodos , Ratas , Ratas Wistar , Privación de Sueño/metabolismo , Privación de Sueño/fisiopatología , Sueño REM/efectos de los fármacosRESUMEN
Traumatic brain injury (TBI) is an alteration in brain function, caused by an external force, which may be a hit on the skull, rapid acceleration or deceleration, penetration of an object, or shock waves from an explosion. Traumatic brain injury is a major cause of morbidity and mortality worldwide, with a high prevalence rate in pediatric patients, in which treatment options are still limited, not available at present neuroprotective drugs. Although the therapeutic management of these patients is varied and dependent on the severity of the injury, general techniques of drug types are handled, as well as physical and surgical. Baclofen is a muscle relaxant used to treat spasticity and improve mobility in patients with spinal cord injuries, relieving pain and muscle stiffness. Pharmacological support with baclofen is contradictory, because disruption of its oral administration may cause increased muscle tone syndrome and muscle spasm, prolonged seizures, hyperthermia, dysesthesia, hallucinations, or even multisystem organ failure. Combined treatments must consider the pathophysiology of broader alterations than only excitation/inhibition context, allowing the patient's reintegration with the greatest functionality.
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Baclofeno/uso terapéutico , Lesiones Traumáticas del Encéfalo/complicaciones , Relajantes Musculares Centrales/uso terapéutico , Espasticidad Muscular/tratamiento farmacológico , Espasticidad Muscular/etiología , Lesiones Traumáticas del Encéfalo/clasificación , Lesiones Traumáticas del Encéfalo/tratamiento farmacológico , Progresión de la Enfermedad , HumanosRESUMEN
During the process of a brain injury, responses to produce damage and cell death are activated, but self-protective responses that attempt to maintain the integrity and functionality of the brain are also activated. We have previously reported that the recovery from a traumatic brain injury (TBI) is better in rats if it occurs during the dark phase of the diurnal cycle when rats are in the waking period. This suggests that wakefulness causes a neuroprotective role in this type of injury. Here we report that 24h of total sleep deprivation after a TBI reduces the morphological damage and enhances the recovery of the rats, as seen on a neurobiological scale.