RESUMO
The development of refractory status epilepticus (SE) following sarin intoxication presents a therapeutic challenge. Here, we evaluated the efficacy of delayed combined double or triple treatment in reducing abnormal epileptiform seizure activity (ESA) and the ensuing long-term neuronal insult. SE was induced in rats by exposure to 1.2 LD50 sarin followed by treatment with atropine and TMB4 (TA) 1 min later. Double treatment with ketamine and midazolam or triple treatment with ketamine, midazolam and levetiracetam was administered 30 min post-exposure, and the results were compared to those of single treatment with midazolam alone or triple treatment with ketamine, midazolam, and valproate, which was previously shown to ameliorate this neurological insult. Toxicity and electrocorticogram activity were monitored during the first week, and behavioral evaluations were performed 2 weeks post-exposure, followed by biochemical and immunohistopathological analyses. Both double and triple treatment reduced mortality and enhanced weight recovery compared to TA-only treatment. Triple treatment and, to a lesser extent, double treatment significantly ameliorated the ESA duration. Compared to the TA-only or the TA+ midazolam treatment, both double and triple treatment reduced the sarin-induced increase in the neuroinflammatory marker PGE2 and the brain damage marker TSPO and decreased gliosis, astrocytosis and neuronal damage. Finally, both double and triple treatment prevented a change in behavior, as measured in the open field test. No significant difference was observed between the efficacies of the two triple treatments, and both triple combinations completely prevented brain injury (no differences from the naïve rats). Delayed double and, to a greater extent, triple treatment may serve as an efficacious delayed therapy, preventing brain insult propagation following sarin-induced refractory SE.
Assuntos
Lesões Encefálicas , Ketamina , Agentes Neurotóxicos , Estado Epiléptico , Ratos , Animais , Sarina/toxicidade , Agentes Neurotóxicos/toxicidade , Midazolam/farmacologia , Midazolam/uso terapêutico , Ratos Sprague-Dawley , Anticonvulsivantes/farmacologia , Anticonvulsivantes/uso terapêutico , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/tratamento farmacológico , Colinérgicos/efeitos adversos , Lesões Encefálicas/induzido quimicamenteRESUMO
rVSV-ΔG-SARS-CoV-2-S is a clinical stage (Phase 2) replication competent recombinant vaccine against SARS-CoV-2. To evaluate the safety profile of the vaccine, a series of non-clinical safety, immunogenicity and efficacy studies were conducted in four animal species, using multiple doses (up to 108 Plaque Forming Units/animal) and dosing regimens. There were no treatment-related mortalities or any noticeable clinical signs in any of the studies. Compared to unvaccinated controls, hematology and biochemistry parameters were unremarkable and no adverse histopathological findings. There was no detectable viral shedding in urine, nor viral RNA detected in whole blood or serum samples seven days post vaccination. The rVSV-ΔG-SARS-CoV-2-S vaccination gave rise to neutralizing antibodies, cellular immune responses, and increased lymphocytic cellularity in the spleen germinal centers and regional lymph nodes. No evidence for neurovirulence was found in C57BL/6 immune competent mice or in highly sensitive type I interferon knock-out mice. Vaccine virus replication and distribution in K18-human Angiotensin-converting enzyme 2-transgenic mice showed a gradual clearance from the vaccination site with no vaccine virus recovered from the lungs. The nonclinical data suggest that the rVSV-ΔG-SARS-CoV-2-S vaccine is safe and immunogenic. These results supported the initiation of clinical trials, currently in Phase 2.
Assuntos
Vacinas contra COVID-19/toxicidade , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Vacinas contra COVID-19/imunologia , Cricetinae , Feminino , Glicoproteínas de Membrana/genética , Mesocricetus , Camundongos , Camundongos Endogâmicos C57BL , Coelhos , Suínos , Vacinação , Vacinas Sintéticas/toxicidade , Proteínas do Envelope Viral/genéticaRESUMO
The development of refractory status epilepticus (SE) induced by sarin intoxication presents a therapeutic challenge. In our current research we evaluate the efficacy of a delayed combined triple treatment in ending the abnormal epileptiform seizure activity (ESA) and the ensuing of long-term neuronal insult. SE was induced in male Sprague-Dawley rats by exposure to 1.2LD50 sarin insufficiently treated by atropine and TMB4 (TA) 1 min later. Triple treatment of ketamine, midazolam and valproic acid was administered 30 min or 1 h post exposure and was compared to a delayed single treatment with midazolam alone. Toxicity and electrocorticogram activity were monitored during the first week and behavioral evaluation performed 3 weeks post exposure followed by brain biochemical and immunohistopathological analyses. The addition of both single and triple treatments reduced mortality and enhanced weight recovery compared to the TA-only treated group. The triple treatment also significantly minimized the duration of the ESA, reduced the sarin-induced increase in the neuroinflammatory marker PGE2, the brain damage marker TSPO, decreased the gliosis, astrocytosis and neuronal damage compared to the TA+ midazolam or only TA treated groups. Finally, the triple treatment eliminated the sarin exposed increased open field activity, as well as impairing recognition memory as seen in the other experimental groups. The delayed triple treatment may serve as an efficient therapy, which prevents brain insult propagation following sarin-induced refractory SE, even if treatment is postponed for up to 1 h.
Assuntos
Anticonvulsivantes/administração & dosagem , Encéfalo/efeitos dos fármacos , Ketamina/administração & dosagem , Midazolam/administração & dosagem , Sarina , Estado Epiléptico/tratamento farmacológico , Ácido Valproico/administração & dosagem , Animais , Comportamento Animal/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Encéfalo/fisiopatologia , Proteínas de Transporte/metabolismo , Dinoprostona/metabolismo , Modelos Animais de Doenças , Esquema de Medicação , Quimioterapia Combinada , Injeções Intramusculares , Injeções Intraperitoneais , Masculino , Teste de Campo Aberto/efeitos dos fármacos , Ratos Sprague-Dawley , Receptores de GABA-A/metabolismo , Reconhecimento Psicológico/efeitos dos fármacos , Estado Epiléptico/induzido quimicamente , Estado Epiléptico/patologia , Estado Epiléptico/fisiopatologia , Fatores de TempoRESUMO
Long-term retrospective monitoring of exposure to organophosphorus nerve agents is challenging. We recently developed two highly sensitive analytical methods for regenerated sarin (GB) nerve agent in blood and its primary metabolite, isopropyl-methylphosphonic acid (IMPA), in urine. These methods were implemented in a toxicokinetics study carried out with sarin injected (i.v.) to rabbits at doses corresponding to 0.1, 0.5 or 0.9 LD50. The time frame for monitoring regenerated sarin from blood was 70 days for 0.1 LD50 and 0.5 LD50 and 77 days for 0.9 LD50, where rapid elimination occurred in the first 8 days with an initial average half-life of 1.2 days, followed by a second, slower elimination, with a terminal average half-life of 8.4 days. The time frame for monitoring IMPA in urine was 7, 15 and 16 days for 0.1 LD50, 0.5 LD50 and 0.9 LD50 intoxications, respectively. Rapid elimination of IMPA in urine occurred after exposure, with an average half-life of ~ 0.8 days on days 2-6. For the first time, a slower elimination route for IMPA, with an average half-life of ~ 4 days from day 6 onwards, was revealed. Both IMPA and regenerated sarin pharmacokinetics exhibit linearity with dose. The overlaid pharmacokinetic profiles of regenerated sarin in blood along with IMPA in urine emphasize the dominance of IMPA with a rapid decay in urine in the first week and the slower long-term decay of protein-bound sarin later in blood. To our knowledge, the two new sensitive methods exhibit the longest monitoring time frame reported in biological samples.
Assuntos
Substâncias para a Guerra Química , Sarina , Animais , Substâncias para a Guerra Química/metabolismo , Compostos Organofosforados/metabolismo , Coelhos , Estudos RetrospectivosRESUMO
BACKGROUND: Sarin is an irreversible organophosphate cholinesterase inhibitor. Following toxic signs, an extensive long-term brain damage is often reported. Thus, we evaluated the efficacy of a novel anticonvulsant drug retigabine, a modulator of neuronal voltage gated K+ channels, as a neuroprotective agent following sarin exposure. METHODS: Rats were exposed to 1 LD50 or 1.2 LD50 sarin and treated at onset of convulsions with retigabine (5 mg/kg, i.p.) alone or in combination with 5 mg/kg atropine and 7.5 mg/kg TMB-4 (TA) respectively. Brain biochemical and immunohistopathological analyses were processed 24 h and 1 week following 1 LD50 sarin exposure and at 4 weeks following exposure to 1.2 LD50 sarin. EEG activity in freely moving rats was also monitored by telemetry during the first week following exposure to 1.2 LD50 and behavior in the Open Field was evaluated 3 weeks post exposure. RESULTS: Treatment with retigabine following 1 LD50 sarin exposure or in combination with TA following 1.2 LD50 exposure significantly reduced mortality rate compared to the non-treated groups. In both experiments, the retigabine treatment significantly reduced gliosis, astrocytosis and brain damage as measured by translocator protein (TSPO). Following sarin exposure the combined treatment (retigabine+ TA) significantly minimized epileptiform seizure activity. Finally, in the Open Field behavioral test the non-treated sarin group showed an increased mobility which was reversed by the combined treatment. CONCLUSIONS: The M current modulator retigabine has been shown to be an effective adjunct therapy following OP induced convulsion, minimizing epileptiform seizure activity and attenuating the ensuing brain damage.
Assuntos
Anticonvulsivantes/administração & dosagem , Encefalopatias/induzido quimicamente , Encefalopatias/prevenção & controle , Carbamatos/administração & dosagem , Fármacos Neuroprotetores/administração & dosagem , Fenilenodiaminas/administração & dosagem , Sarina/toxicidade , Animais , Atropina/administração & dosagem , Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Encefalopatias/patologia , Substâncias para a Guerra Química/toxicidade , Inibidores da Colinesterase/toxicidade , Masculino , Neuroglia/patologia , Neurônios/patologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos dos fármacos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/fisiologia , Ratos , Ratos Sprague-Dawley , Convulsões/induzido quimicamente , Convulsões/prevenção & controle , Trimedoxima/administração & dosagemRESUMO
Highly toxic organophosphorous nerve agents (OPAs) have been used in several armed conflicts and terror attacks in the last few decades. A new method for retrospective determination of alkyl methylphosphonic acid (AMPA) metabolites in urine after exposure to VX, GB and GF nerve agents was developed. This method enables a rapid, sensitive and selective determination of trace levels of the nerve agent biomarkers ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA) and cyclohexyl methylphosphonic acid (CMPA) in urine. The new technique involves a unique combination of two solid phase extraction (SPE) cartridges: a Ba/Ag/H cartridge for urine interference removal, and a ZrO2 cartridge for selective reconstitution and enrichment of the AMPAs. Extraction of AMPAs from the ZrO2 cartridge was accomplished with a 1% ammonium hydroxide (NH4OH) solution and was followed by analysis via liquid chromatography-mass spectrometry (LC-MS). The limits of quantitation (LOQs) were in the range of 10-100 pg/mL with recoveries of 64-71% (± 5-19%) after fast sample preparation and a total LC-MS analysis cycle time of 15 min and 13 min, respectively. This method was successfully applied in vivo in a rabbit that was exposed to 0.5 LD50 (7.5 µg/kg, i.v.) sarin for retrospective monitoring of the IMPA metabolite in urine. For the first time, IMPA was determined in rabbit urine samples for 15 days post-exposure, which is longer than any reported post-exposure method for AMPAs. To the best of our knowledge, this new method is the most sensitive and rapid for AMPA determination in urine by LC-MS/MS analysis.
Assuntos
Agentes Neurotóxicos/toxicidade , Compostos Organofosforados/toxicidade , Animais , Biomarcadores/urina , Substâncias para a Guerra Química , Humanos , Agentes Neurotóxicos/metabolismo , Organofosfonatos , Compostos Organofosforados/urina , Coelhos , Estudos Retrospectivos , Sarina , Extração em Fase SólidaRESUMO
The highly toxic nerve agent sarin (o-isopropyl methyl-phosphonofluoridate, GB) has been used in several armed conflicts and terror attacks in recent decades. Due to its inherent high sensitivity, liquid chromatography-mass spectrometry (LC-MS/MS) has the potential to detect ultratrace levels of fluoride-regenerated G and V agents after appropriate chemical derivatization. A new method for the retrospective determination of exposure to sarin was developed. The method is based on sarin regeneration from blood using the fluoride-induced technique followed by derivatization with 2-[(dimethylamino)methyl]phenol (2-DMAMP) and LC-ESI-MS/MS (MRM) analysis. The validated method presents good linear response in the concentration range of 5-1000 pg/mL with a limit of quantitation (LOQ) of 5 pg/mL, 13.8% accuracy, 16.7% precision and a total recovery of 62% ± 9%. This new analytical approach has several advantages over existing GC/GC-MS-based methods in terms of sensitivity, specificity and simplicity, in addition to a short LC-MS cycle time of 12 min. The method was successfully applied in an in vivo experiment for retrospective determination of sarin in a rabbit exposed to 0.1 LD50 sarin (1.5 µg/kg, i.v.). GB-2-DMAMP was easily determined in samples drawn up to 11 days after exposure. The high S/N ratio (500) observed for the GB-2-DMAMP signal in the 11day sample poses the potential for an extended time frame of months for analysis with this new method for the retrospective detection of sarin exposure. To the best of our knowledge, this is the first report on LC-MS/MS trace analysis of regenerated GB from biological matrices.
Assuntos
Cromatografia Líquida/métodos , Agentes Neurotóxicos/análise , Sarina/sangue , Espectrometria de Massas em Tandem/métodos , Animais , Feminino , Fluoretos/química , Meia-Vida , Humanos , Limite de Detecção , Agentes Neurotóxicos/química , Agentes Neurotóxicos/farmacocinética , Coelhos , Sarina/química , Sarina/farmacocinética , Sensibilidade e Especificidade , Solventes/químicaRESUMO
Objective: Sarin is an irreversible organophosphate cholinesterase inhibitor and a highly toxic, volatile warfare agent. Rats and guinea pigs exposed to sarin display cholinergic excitotoxicity which includes hyper-salivation, respiratory distress, tremors, seizures, and death. Here we focused on the characterization of the airways injury induced by direct exposure of the lungs to sarin vapor and compared it to that induced by the intramuscularly route. Materials and methods: Rats were exposed to sarin either in vapor (â¼1LCT50, 34.2 ± 0.8 µg/l/min, 10 min) or by i.m. (â¼1LD50, 80 µg/kg), and lung injury was evaluated by broncho-alveolar lavage (BAL). Results and discussion: BAL analysis revealed route-dependent effects in rats: vapor exposed animals showed elevation of inflammatory cytokines, protein, and neutrophil cells. These elevations were seen at 24 h and were still significantly higher compared to control values at 1 week following vapor exposure. These elevations were not detected in rats exposed to sarin i.m. Histological evaluation of the brains revealed typical changes following sarin poisoning independent of the route of administration. The airways damage following vapor exposure in rats was also compared to that induced in guinea pigs. The latter showed increased eosinophilia and histamine levels that constitutes an anaphylactic response not seen in rats. Conclusions: These data clearly point out the importance of using the appropriate route of administration in studying the deleterious effects of volatile nerve agents, as well as the selection of the appropriate animal species. Since airways form major target organs for the development of injury following inhalation toxicity, they should be included in any comprehensive evaluation of countermeasures efficacy.
Assuntos
Substâncias para a Guerra Química/toxicidade , Pulmão/patologia , Sarina/administração & dosagem , Sarina/toxicidade , Administração por Inalação , Animais , Lavagem Broncoalveolar , Inibidores da Colinesterase/administração & dosagem , Inibidores da Colinesterase/toxicidade , Cobaias , Inflamação , Injeções Intramusculares , Dose Letal Mediana , Pulmão/efeitos dos fármacos , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Sarin is an irreversible organophosphate cholinesterase inhibitor and a highly toxic warfare agent. Following the overt, dose-dependent signs (e.g. tremor, hyper secretion, seizures, respiratory depression and eventually death), brain damage is often reported. The goal of the present study was to characterize the early histopathological and biochemical events leading to this damage. Rats were exposed to 1LD50 of sarin (80µg/kg, i.m.). Brains were removed at 1, 2, 6, 24 and 48h and processed for analysis. Results showed that TSPO (translocator protein) mRNA increased at 6h post exposure while TSPO receptor density increased only at 24h. In all brain regions tested, bax mRNA decreased 1h post exposure followed by an increase 24h later, with only minor increase in bcl2 mRNA. At this time point a decrease was seen in both anti-apoptotic protein Bcl2 and pro-apoptotic Bax, followed by a time and region specific increase in Bax. An immediate elevation in ERK1/2 activity with no change in JNK may indicate an endogenous "first response" mechanism used to attenuate the forthcoming apoptosis. The time dependent increase in the severity of brain damage included an early bi-phasic activation of astrocytes, a sharp decrease in intact neuronal cells, a time dependent reduction in MAP2 and up to 15% of apoptosis. Thus, neuronal death is mostly due to necrosis and severe astrocytosis. The data suggests that timing of possible treatments should be determined by early events following exposure. For example, the biphasic changes in astrocytes activity indicate a possible beneficial effects of delayed anti-inflammatory intervention.
Assuntos
Encéfalo/efeitos dos fármacos , Inibidores da Colinesterase/toxicidade , Sarina/toxicidade , Animais , Substâncias para a Guerra Química , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Ricin, a highly potent plant-derived toxin, is considered a potential bioterrorism weapon due to its pronounced toxicity, high availability, and ease of preparation. Acute damage following pulmonary ricinosis is characterized by local cytokine storm, massive neutrophil infiltration, and edema formation, resulting in respiratory insufficiency and death. A designated equine polyclonal antibody-based (antitoxin) treatment was developed in our laboratory and proved efficacious in alleviating lung injury and increasing survival rates. Although short-term pathogenesis was thoroughly characterized in antitoxin-treated mice, the long-term damage in surviving mice was never determined. In this study, long-term consequences of ricin intoxication were evaluated 30 days post-exposure in mice that survived antitoxin treatment. Significant pulmonary sequelae were demonstrated in surviving antitoxin-treated mice, as reflected by prominent histopathological changes, moderate fibrosis, increased lung hyperpermeability, and decreased lung compliance. The presented data highlight, for the first time to our knowledge, the possibility of long-term damage development in mice that survived lethal-dose pulmonary exposure to ricin due to antitoxin treatment.
Assuntos
Antitoxinas , Lesão Pulmonar , Insuficiência Respiratória , Ricina , Animais , Cavalos , Camundongos , Antitoxinas/uso terapêutico , Ricina/toxicidade , Pulmão/patologia , Lesão Pulmonar/tratamento farmacológicoRESUMO
Sarin, a potent organophosphate cholinesterase inhibitor, induces an array of toxic effects including convulsions. Many antidotal treatments contain anticonvulsants to block seizure activity and the ensuing brain damage. Magnesium sulfate (MGS) is used to suppress eclamptic seizures in pregnant women with hypertension and was shown to block kainate-induced convulsions. Magnesium sulfate was evaluated herein as an anticonvulsant against sarin poisoning and its efficacy was compared with the potent anticonvulsants midazolam (MDZ) and caramiphen (CRM). Rats were exposed to a convulsant dose of sarin (96 µg/kg, im) and 1 min later treated with the oxime TMB4 and atropine to increase survival. Five minutes after initiation of convulsions, MGS, CRM, or MDZ were administered. Attenuation of tonic-clonic convulsions was observed following all these treatments. However, radio-telemetric electro-corticography (ECoG) monitoring demonstrated sustained seizure activity in MGS-injected animals while this activity was completely blocked by MDZ and CRM. This disrupted brain activity was associated with marked increase in brain translocator protein levels, a marker for brain damage, measured 1 week following exposure. Additionally, histopathological analyses of MGS-treated group showed typical sarin-induced brain injury excluding the hippocampus that was partially protected. Our results clearly show that MGS demonstrated misleading features as an anticonvulsant against sarin-induced seizures. This stems from the dissociation observed between overt convulsions and seizure activity. Thus, the presence or absence of motor convulsions may be an unreliable indicator in the assessment of clinical status and in directing adequate antidotal treatments following exposure to nerve agents in battle field or terror attacks.
Assuntos
Anticonvulsivantes/farmacologia , Antídotos/farmacologia , Substâncias para a Guerra Química/intoxicação , Sulfato de Magnésio/farmacologia , Sarina/intoxicação , Convulsões/tratamento farmacológico , Animais , Lesões Encefálicas/induzido quimicamente , Lesões Encefálicas/patologia , Lesões Encefálicas/fisiopatologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/patologia , Córtex Cerebral/fisiopatologia , Ciclopentanos/farmacologia , Epilepsia Tônico-Clônica , Masculino , Midazolam/farmacologia , Ratos , Ratos Sprague-Dawley , Convulsões/induzido quimicamente , Convulsões/fisiopatologia , TelemetriaRESUMO
Organophosphates are highly toxic substances, which cause severe brain damage. The hallmark of the brain injury is major convulsions. The goal of this study was to assess the spatial and temporal MR changes in the brain of paraoxon intoxicated rats. T2-weighted MRI and ¹H-MR-spectroscopy were conducted before intoxication, 3 h, 24 h, and 8 days postintoxication. T2 prolongation mainly in the thalami and cortex was evident as early as 3 h after intoxication (4-6% increase in T2 values, P < 0.05). On spectroscopy, N-acetyl aspartate (NAA)/creatine and NAA/choline levels significantly decreased 3 h postintoxication (>20% decrease, P < 0.005), and 3 h lactate peak was evident in all intoxicated animals. On the 8th day, although very little T2 changes were evident, NAA/creatine and choline/creatine were significantly decreased (>15%, P < 0.05). Animals who succumbed had extensive cortical edema, significant higher lactate levels and a significant decrease in NAA/creatine and NAA/choline levels compared to animals which survived the experiment. Organophosphates-induced brain damage is obvious on MR data already 3 h postintoxication. In vivo spectroscopic changes are more sensitive for assessing long-term injury than T2-weighted MR imaging. Early spectroscopic findings might be used as biomarkers for the severity of the intoxication and might predict early survival.
Assuntos
Lesões Encefálicas/diagnóstico , Lesões Encefálicas/metabolismo , Síndromes Neurotóxicas/diagnóstico , Síndromes Neurotóxicas/metabolismo , Intoxicação por Organofosfatos/diagnóstico , Intoxicação por Organofosfatos/metabolismo , Paraoxon/toxicidade , Algoritmos , Animais , Lesões Encefálicas/induzido quimicamente , Estudos de Viabilidade , Inseticidas/toxicidade , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Masculino , Síndromes Neurotóxicas/etiologia , Prognóstico , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Medição de Risco/métodos , Sensibilidade e Especificidade , Análise de SobrevidaRESUMO
Fundamental key processes in viral infection cycles generally occur in distinct cellular sites where both viral and host factors accumulate and interact. These sites are usually termed viral replication organelles, or viral factories (VF). The generation of VF is accompanied by the synthesis of viral proteins and genomes and involves the reorganization of cellular structure. Recently, rVSV-ΔG-spike (VSV-S), a recombinant VSV expressing the SARS-CoV-2 spike protein, was developed as a vaccine candidate against SARS-CoV-2. By combining transmission electron microscopy (TEM) tomography studies and immuno-labeling techniques, we investigated the infection cycle of VSV-S in Vero E6 cells. RT-real-time-PCR results show that viral RNA synthesis occurs 3-4 h post infection (PI), and accumulates as the infection proceeds. By 10-24 h PI, TEM electron tomography results show that VSV-S generates VF in multi-lamellar bodies located in the cytoplasm. The VF consists of virus particles with various morphologies. We demonstrate that VSV-S infection is associated with accumulation of cytoplasmatic viral proteins co-localized with dsRNA (marker for RNA replication) but not with ER membranes. Newly formed virus particles released from the multi-lamellar bodies containing VF, concentrate in a vacuole membrane, and the infection ends with the budding of particles after the fusion of the vacuole membrane with the plasma membrane. In summary, the current study describes detailed 3D imaging of key processes during the VSV-S infection cycle.
Assuntos
COVID-19 , Vírus da Estomatite Vesicular Indiana , Humanos , Vírus da Estomatite Vesicular Indiana/genética , SARS-CoV-2 , Proteínas Virais/metabolismoRESUMO
SARS-CoV-2, a member of the coronavirus family, is the causative agent of the COVID-19 pandemic. Currently, there is still an urgent need in developing an efficient therapeutic intervention. In this study, we aimed at evaluating the therapeutic effect of a single intranasal treatment of the TLR3/MDA5 synthetic agonist Poly(I:C) against a lethal dose of SARS-CoV-2 in K18-hACE2 transgenic mice. We demonstrate here that early Poly(I:C) treatment acts synergistically with SARS-CoV-2 to induce an intense, immediate and transient upregulation of innate immunity-related genes in lungs. This effect is accompanied by viral load reduction, lung and brain cytokine storms prevention and increased levels of macrophages and NK cells, resulting in 83% mice survival, concomitantly with long-term immunization. Thus, priming the lung innate immunity by Poly(I:C) or alike may provide an immediate, efficient and safe protective measure against SARS-CoV-2 infection.
Assuntos
COVID-19/imunologia , COVID-19/prevenção & controle , Imunidade Inata , Poli I-C/imunologia , Poli I-C/uso terapêutico , SARS-CoV-2/efeitos dos fármacos , Receptor 3 Toll-Like/agonistas , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/imunologia , Animais , Síndrome da Liberação de Citocina/imunologia , Síndrome da Liberação de Citocina/prevenção & controle , Modelos Animais de Doenças , Feminino , Humanos , Pulmão/imunologia , Pulmão/virologia , Camundongos , Camundongos Transgênicos , SARS-CoV-2/imunologia , Receptor 3 Toll-Like/imunologia , Carga Viral/efeitos dos fármacos , Tratamento Farmacológico da COVID-19RESUMO
Recent advances in the field of cell therapy have proposed new solutions for tissue repair and regeneration using various cell delivery approaches. Here we studied ex vivo a novel topical delivery system of encapsulated cells in hybrid polyethylene glycol-fibrinogen (PEG-Fb) hydrogel microspheres to respiratory tract models. We investigated basic parameters of cell encapsulation, delivery and release in conditions of inflamed and damaged lungs of bacterial-infected mice. The establishment of each step in the study was essential for the proof of concept. We demonstrated co-encapsulation of alveolar macrophages and epithelial cells that were highly viable and equally distributed inside the microspheres. We found that encapsulated macrophages exposed to bacterial endotoxin lipopolysaccharide preserved high viability and secreted moderate levels of TNFα, whereas non-encapsulated cells exhibited a burst TNFα secretion and reduced viability. LPS-exposed encapsulated macrophages exhibited elongated morphology and out-migration capability from microspheres. Microsphere degradation and cell release in inflamed lung environment was studied ex vivo by the incubation of encapsulated macrophages with lung extracts derived from intranasally infected mice with Yersinia pestis, demonstrating the potential in cell targeting and release in inflamed lungs. Finally, we demonstrated microsphere delivery to a multi-component airways-on-chip platform that mimic human nasal, bronchial and alveolar airways in serially connected compartments. This study demonstrates the feasibility in using hydrogel microspheres as an effective method for topical cell delivery to the lungs in the context of pulmonary damage and the need for tissue repair.
RESUMO
Government-sanctioned use of nerve agents (NA) has escalated dramatically in recent years. Oxime reactivators of organophosphate (OP)-inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) serve as antidotes toward poisoning by OPNAs. The oximes used as therapeutics are quaternary compounds that cannot penetrate the blood-brain barrier (BBB). There remains an urgent need for the development of next generation OPNA therapeutics. We have developed two high-throughput screening (HTS) assays using a fluorogenic NA surrogate, O-ethyl methylphosphonyl O-4-methyl-3-cyano-coumarin (EMP-MeCyC). EMP-MeCyC detoxification and EMP-BChE reactivation screening campaigns of ~155,000 small molecules resulted in the identification of 33 nucleophile candidates, including non-quaternary oximes. Four of the oximes were reactivators of both Sarin- and VX-inhibited BChE and directly detoxified Sarin. One oxime also detoxified VX. The novel reactivators included a non-quaternary pyridine amidoxime, benzamidoxime, benzaldoxime and a piperidyl-ketoxime. The VX-inhibited BChE reactivation reaction rates by these novel molecules were similar to those observed with known bis-quaternary reactivators and faster than mono-quaternary pyridinium oximes. Notably, we discovered the first ketoxime reactivator of OP-ChEs and detoxifier of OPNAs. Preliminary toxicological studies demonstrated that the newly discovered non-quaternary oximes were relatively non-toxic in mice. The discovery of unique non-quaternary oximes opens the door to the design of novel therapeutics and decontamination agents following OPNA exposure.
Assuntos
Barreira Hematoencefálica/efeitos dos fármacos , Butirilcolinesterase/química , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/farmacologia , Agentes Neurotóxicos/toxicidade , Oximas/farmacologia , Animais , Ativação Enzimática , Humanos , Masculino , Camundongos , Camundongos Endogâmicos ICRRESUMO
Mice are normally unaffected by SARS coronavirus 2 (SARS-CoV-2) infection since the virus does not bind effectively to the murine version of the angiotensin-converting enzyme 2 (ACE2) receptor molecule. Here, we report that induced mild pulmonary morbidities rendered SARS-CoV-2-refractive CD-1 mice susceptible to this virus. Specifically, SARS-CoV-2 infection after application of low doses of the acute lung injury stimulants bleomycin or ricin caused severe disease in CD-1 mice, manifested by sustained body weight loss and mortality rates greater than 50%. Further studies revealed markedly higher levels of viral RNA in the lungs, heart, and serum of low-dose ricin-pretreated mice compared with non-pretreated mice. Furthermore, lung extracts prepared 2-3 days after viral infection contained subgenomic mRNA and virus particles capable of replication only when derived from the pretreated mice. The deleterious effects of SARS-CoV-2 infection were effectively alleviated by passive transfer of polyclonal or monoclonal antibodies generated against the SARS-CoV-2 receptor binding domain (RBD). Thus, viral cell entry in the sensitized mice seems to depend on viral RBD binding, albeit by a mechanism other than the canonical ACE2-mediated uptake route. This unique mode of viral entry, observed over a mildly injured tissue background, may contribute to the exacerbation of coronavirus disease 2019 (COVID-19) pathologies in patients with preexisting morbidities.
Assuntos
Bleomicina/toxicidade , COVID-19/patologia , Lesão Pulmonar , Ricina/toxicidade , Animais , Chlorocebus aethiops , Comorbidade , Modelos Animais de Doenças , Feminino , Lesão Pulmonar/induzido quimicamente , Lesão Pulmonar/virologia , Camundongos , Células Vero , Ligação Viral , Internalização do Vírus/efeitos dos fármacosRESUMO
Dry blood spot (DBS), a micro whole-blood sampling technique, enables rapid and self-blood collection; it is stable and economical. Currently, DBS filters require various sample preparation procedures specifically tailored for the target compounds, which are followed by GC-MS or LC-MS analysis. However, the small amounts of blood make the approach analytically challenging, mostly in terms of sensitivity and quantification. Herein, we introduce a new DBS concept for GC-compatible volatile to semi-volatile compounds in which DBS is directly coupled with thermal desorption analysis, thus eliminating time consuming treatments. Furthermore, to stabilize the target compound over the sampling DBS substrate, a commercial filter based on an extremely efficient trapping adsorption phase, styrene-divinylbenzene (SDVB), is first used. The performance of the new SDVB-DBS concept was demonstrated herein for monitoring the most volatile chemical warfare agent, sarin, which might be present in blood and the detection of which is usually challenging due to its rapid metabolism. This study encompasses adequate sampling and analysis method parametrization and validation, leading to a detection sensitivity of 100â¯pg sarin per 30⯵L whole blood in 5-day-old samples, with a linear dynamic range of two orders of magnitude, adequate precision, and acceptable accuracy. Applying the method to an in-vivo mouse intranasal exposure experiment (3LD50 GB) enabled the successful detection of 25-90â¯ngâ¯mL-1 free sarin in blood samples drawn 2â¯min after exposure. The method's performance clearly emphasizes the potential of the new concept in "freezing the clock" for reactive whole blood media in pharmacokinetics and pharmacodynamics studies, as well as in applications in which informative and reliable monitoring of unstable target compounds and biomarkers is desired.
Assuntos
Teste em Amostras de Sangue Seco/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Sarina/sangue , Adsorção , Animais , Limite de Detecção , Modelos Lineares , Masculino , Camundongos , Camundongos Endogâmicos ICR , Reprodutibilidade dos Testes , Estireno/química , Compostos de Vinila/químicaRESUMO
Angiogenesis and lymphangiogenesis are key processes during embryogenesis as well as under physiological and pathological conditions. Vascular endothelial growth factor C (VEGFC), the ligand for both VEGFR2 and VEGFR3, is a central lymphangiogenic regulator that also drives angiogenesis. Here, we report that members of the highly conserved BACH (BTB and CNC homology) family of transcription factors regulate VEGFC expression, through direct binding to its promoter. Accordingly, down-regulation of bach2a hinders blood vessel formation and impairs lymphatic sprouting in a Vegfc-dependent manner during zebrafish embryonic development. In contrast, BACH1 overexpression enhances intratumoral blood vessel density and peritumoral lymphatic vessel diameter in ovarian and lung mouse tumor models. The effects on the vascular compartment correlate spatially and temporally with BACH1 transcriptional regulation of VEGFC expression. Altogether, our results uncover a novel role for the BACH/VEGFC signaling axis in lymphatic formation during embryogenesis and cancer, providing a novel potential target for therapeutic interventions.
Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/genética , Proteínas de Grupos de Complementação da Anemia de Fanconi/genética , Neovascularização Fisiológica/fisiologia , Fator C de Crescimento do Endotélio Vascular/genética , Proteínas de Peixe-Zebra/genética , Moduladores da Angiogênese/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Linhagem Celular Tumoral , Proteínas de Grupos de Complementação da Anemia de Fanconi/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento/genética , Humanos , Linfangiogênese/fisiologia , Vasos Linfáticos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Nus , Morfogênese , Transdução de Sinais , Fator C de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/genética , Peixe-Zebra/embriologia , Proteínas de Peixe-Zebra/metabolismoRESUMO
Successful implantation is associated with a unique spatial pattern of vascular remodeling, characterized by profound peripheral neovascularization surrounding a periembryo avascular niche. We hypothesized that hyaluronan controls the formation of this distinctive vascular pattern encompassing the embryo. This hypothesis was evaluated by genetic modification of hyaluronan metabolism, specifically targeted to embryonic trophoblast cells. The outcome of altered hyaluronan deposition on uterine vascular remodeling and postimplantation development were analyzed by MRI, detailed histological examinations, and RNA sequencing of uterine NK cells. Our experiments revealed that disruption of hyaluronan synthesis, as well as its increased cleavage at the embryonic niche, impaired implantation by induction of decidual vascular permeability, defective vascular sinus folds formation, breach of the maternal-embryo barrier, elevated MMP-9 expression, and interrupted uterine NK cell recruitment and function. Conversely, enhanced deposition of hyaluronan resulted in the expansion of the maternal-embryo barrier and increased diffusion distance, leading to compromised implantation. The deposition of hyaluronan at the embryonic niche is regulated by progesterone-progesterone receptor signaling. These results demonstrate a pivotal role for hyaluronan in successful pregnancy by fine-tuning the periembryo avascular niche and maternal vascular morphogenesis.