RESUMEN
BACKGROUND: Devic's neuromyelitis optica (NMO) is an autoimmune astrocytopathy, associated with central nervous system inflammation, demyelination, and neuronal injury. Several studies confirmed that autoantibodies directed against aquaporin-4 (AQP4-IgG) are relevant in the pathogenesis of NMO, mainly through complement-dependent toxicity leading to astrocyte death. However, the effect of the autoantibody per se and the exact role of intrathecal AQP4-IgG are still controversial. METHODS: To explore the intrinsic effect of intrathecal AQP4-IgG, independent from additional inflammatory effector mechanisms, and to evaluate its clinical impact, we developed a new animal model, based on a prolonged infusion of purified immunoglobulins from NMO patient (IgG(AQP4+), NMO-rat) and healthy individual as control (Control-rat) in the cerebrospinal fluid (CSF) of live rats. RESULTS: We showed that CSF infusion of purified immunoglobulins led to diffusion in the brain, spinal cord, and optic nerves, the targeted structures in NMO. This was associated with astrocyte alteration in NMO-rats characterized by loss of aquaporin-4 expression in the spinal cord and the optic nerves compared to the Control-rats (p = 0.001 and p = 0.02, respectively). In addition, glutamate uptake tested on vigil rats was dramatically reduced in NMO-rats (p = 0.001) suggesting that astrocytopathy occurred in response to AQP4-IgG diffusion. In parallel, myelin was altered, as shown by the decrease of myelin basic protein staining by up to 46 and 22 % in the gray and white matter of the NMO-rats spinal cord, respectively (p = 0.03). Loss of neurofilament positive axons in NMO-rats (p = 0.003) revealed alteration of axonal integrity. Then, we investigated the clinical consequences of such alterations on the motor behavior of the NMO-rats. In a rotarod test, NMO-rats performance was lower compared to the controls (p = 0.0182). AQP4 expression, and myelin and axonal integrity were preserved in AQP4-IgG-depleted condition. We did not find a major immune cell infiltration and microglial activation nor complement deposition in the central nervous system, in our model. CONCLUSIONS: We establish a link between motor-deficit, NMO-like lesions and astrocytopathy mediated by intrathecal AQP4-IgG. Our study validates the concept of the intrinsic effect of autoantibody against surface antigens and offers a model for testing antibody and astrocyte-targeted therapies in NMO.
Asunto(s)
Acuaporina 4/inmunología , Astrocitos/efectos de los fármacos , Líquido Cefalorraquídeo/fisiología , Inmunoglobulina G/administración & dosificación , Neuromielitis Óptica/líquido cefalorraquídeo , Neuromielitis Óptica/etiología , Animales , Animales Recién Nacidos , Acuaporina 4/metabolismo , Astrocitos/ultraestructura , Axones/patología , Axones/ultraestructura , Células Cultivadas , Líquido Cefalorraquídeo/efectos de los fármacos , Modelos Animales de Enfermedad , Proteína Ácida Fibrilar de la Glía/metabolismo , Ácido Glutámico/metabolismo , Humanos , Trastornos del Movimiento/complicaciones , Proteína Básica de Mielina/metabolismo , Vaina de Mielina/metabolismo , Vaina de Mielina/patología , Neuromielitis Óptica/complicaciones , Neuromielitis Óptica/patología , Nervio Óptico/patología , Nervio Óptico/ultraestructura , Ratas , Médula Espinal/patología , Médula Espinal/ultraestructuraRESUMEN
Collapsin Response Mediator Protein (CRMP)-2 is involved in T-cell polarization and migration. To address the role of CRMP2 in neuroinflammation, we analyzed its involvement in lymphocyte recruitment to the central nervous system in mouse infected with neurotropic and non-neurotropic virus strains (RABV, CDV). A sub-population of early-activated CD69+CD3+ T lymphocytes highly expressing CRMP2 (CRMP2hi) peaked in the blood, lymph nodes and brain of mice infected with neurotropic viruses, and correlated with severity of disease. They displayed high migratory properties reduced by CRMP2 blocking antibody. These data point out the potential use of CRMP2 as a peripheral indicator of neuroinflammation.
Asunto(s)
Encéfalo/inmunología , Moquillo/inmunología , Encefalitis Viral/inmunología , Péptidos y Proteínas de Señalización Intercelular/fisiología , Proteínas del Tejido Nervioso/fisiología , Rabia/inmunología , Linfocitos T/fisiología , Animales , Antígenos CD/análisis , Antígenos de Diferenciación de Linfocitos T/análisis , Encéfalo/patología , Complejo CD3/análisis , Movimiento Celular , Encefalitis Viral/patología , Femenino , Péptidos y Proteínas de Señalización Intercelular/análisis , Lectinas Tipo C , Ratones , Ratones Endogámicos BALB C , Proteínas del Tejido Nervioso/análisis , Linfocitos T/químicaRESUMEN
Obesity results from disturbances of tightly regulated interactions between the nervous, endocrine, and metabolic systems that can be caused by external factors, such as viral infections. A mouse model of obesity induced by brain infection with a morbillivirus, canine distemper virus, allowed us to identify obesity-related genes. Using a subtractive library for the hypothalamus, the main brain structure regulating energy homeostasis, we identified a new gene on mouse chromosome 19 which we named upregulated obese product (Urop) 11 and, which has no homology with any known mRNA. A step-by-step molecular approach allowed us to isolate the full-length mRNA, predict the protein sequence, and identify consensus sites. Urop11 was mainly detected in the hypothalamus and adipocytes, and was dramatically upregulated in these central and peripheral structures in obese mice. Urop11 was also expressed in human neural and lymphoid samples and its expression seemed to be regulated by the state of lymphocyte activation. Interestingly, Urop11 expression was strongly upregulated both in vivo in mouse hypothalamus and in vitro in mouse neural cell lines, after leptin treatment. Taken together, our data show that Urop11 is a target of leptin, the satiety factor produced by adipocytes, in physiological and pathological conditions, including obesity. This new gene can be considered a key molecule in the hypothalamic integration pathway and demonstrates the importance of Urop11 as a target of leptin action.
Asunto(s)
Hipotálamo/metabolismo , Leptina/fisiología , Proteínas del Tejido Nervioso/genética , Obesidad/metabolismo , Regulación hacia Arriba/fisiología , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Línea Celular , Moquillo/metabolismo , Virus del Moquillo Canino , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/biosíntesis , Obesidad/virologíaRESUMEN
The aim of this study was to investigate interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) production by peripheral blood mononuclear cells (PBMC) in response to oral challenge in patients with food allergy. Thirty-one patients were compared with 10 healthy subjects. Cell cultures were prepared before and 150 min after single-blind, placebo-controlled, oral food challenge. In vitro production of cytokines was observed after stimulation with phytohemagglutinin (PHA) plus phorbol myristate acetate (PMA). Patients were characterized according to their reactions. In vitro IL-4 production was significantly greater in patients with food sensitization than in controls. The 18 patients with positive food challenge presented significantly greater IL-4 production after food challenge than before. IFN-gamma production was not modified. In the 10 control subjects and in 13 patients with negative food challenge, IL-4 and IFN-gamma production was comparable before and after food challenge. The increased IL-4 production in patients with positive oral food challenge could account for the development of polysensitization. This situation might be relevant to other allergic diseases and to treatments.
Asunto(s)
Hipersensibilidad a los Alimentos/inmunología , Interleucina-4/biosíntesis , Leucocitos Mononucleares/inmunología , Adolescente , Adulto , Anciano , Niño , Femenino , Alimentos , Hipersensibilidad a los Alimentos/metabolismo , Humanos , Interferón gamma/biosíntesis , Interferón gamma/inmunología , Interleucina-4/inmunología , Leucocitos Mononucleares/metabolismo , Masculino , Persona de Mediana Edad , Método Simple CiegoRESUMEN
The fragment of the Fc segment of IgE resistant to proteolytic enzymes was determined by a radioimmunologic method in fecal extracts from several groups of patients. IgEs remained undetectable in the 95 healthy subjects studied. IgEs were detected in 16/27 carriers of intestinal parasites (60%), with a mean of 92.4 IU/g dry weight. IgEs were also detected in 236/312 food-sensitization patients, with the sensitizing foodstuffs being identified by searching for the specific IgEs in circulation (75%), with a mean of 63.9 IU/g dry weight. The simultaneous determination of alpha-1-antitrypsin in fecal extracts and in sera from 21 control subjects and 21 food-sensitization carriers demonstrated that extravasation of plasma proteins into the gut lumen cannot be responsible for the presence of IgE in stools. Testing for IgE in stools therefore appears to be a simple and economical means of identifying patients without parasites who present with food sensitization.
Asunto(s)
Heces/química , Hipersensibilidad a los Alimentos/diagnóstico , Inmunoglobulina E/análisis , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Niño , Preescolar , Diagnóstico Diferencial , Femenino , Hipersensibilidad a los Alimentos/inmunología , Humanos , Lactante , Parasitosis Intestinales/diagnóstico , Parasitosis Intestinales/inmunología , Masculino , Persona de Mediana EdadRESUMEN
Food allergy is a group of distinct clinico-pathological entities that have an immunological basis in common, and in which an abnormal or exaggerated immunological response to a specific food leads to disease. Some clinical pictures involving multiple organ system (anaphylaxis) are potentially fatal. The data on the incidence, prevalence, mortality rate and food products involved in food-induced anaphylaxis and the evolution of food sensitization compared with changes in eating habits are not very reliable. In the present study we analysed, over a period of 9 years (1984-1992), a group of 580 patients with pathological reactions to foods, 60 of which presented severe, near-fatal reactions. We sought the etiologic components and food sensitization in comparison with the principal tendencies of food consumption in France. Food products most frequently incriminated in anaphylactic reactions are not of a primary nutritional importance: celery (30%), crustaceans (17%), fish (13%), peanuts (12%), mango (6%), mustard (3%), but they are often hidden allergens in commercial foods. The sensitization to food products in the group of 580 patients reveals, in decreasing order of frequency: wheat (39%), peanuts (37%), crab (34%), celery (30%), soy (30%). Compared with previous data, the frequency of sensitization to different foods has changed; for instance, the sensitizations to wheat, soy, peanuts, celery, mustard, rice, are definitely increasing. The increased consumption and more attentive clinical research may be the reasons for this evolution. For products such as egg and pork, the data are stable and parallel with consumption, whilst for other products like milk and other dairy products, the increased consumption is accompanied by a decrease of the incidence of sensitization. The reactivity to some allergens may be affected by the way of preparing the food.
Asunto(s)
Alérgenos/administración & dosificación , Hipersensibilidad a los Alimentos/etiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anafilaxia/etiología , Niño , Preescolar , Femenino , Hipersensibilidad a los Alimentos/diagnóstico , Hipersensibilidad a los Alimentos/epidemiología , Francia/epidemiología , Humanos , Lactante , Masculino , Persona de Mediana EdadRESUMEN
Intestinal absorption of mannitol (used as a marker of normal monomer passage) and intestinal absorption of lactulose (used as a marker of macromolecule exclusion) were measured in 15 healthy subjects and in 20 patients with food allergy. When studied in the fasting state, there was no apparent difference in the absorption of mannitol between control subjects and allergic patients although the absorption of lactulose was more marked, but not significantly, in the latter group. Ingestion of an allergen by these patients led to a significant increase in the absorption of lactulose (intestinal passage increased by a factor of two). Administration of 300 mg cromoglycate 1/4 hour before the provocation test completely averted abnormal intestinal permeability. Digestive absorption of cromoglycate was also studied in the same 15 control subjects and 20 allergic patients. The peak plasma concentration and area under the curve were significantly greater in healthy subjects when the study was carried out in the fasting state. The application of an oral provocation test with an allergen also significantly increased the plasma concentration of cromoglycate in allergic patients. Contact between an allergen and the digestive tract in allergic patients therefore leads to an increased intestinal absorption of macromolecules but also to cromoglycate passage, which inhibits allergic reactions.
Asunto(s)
Cromolin Sódico/metabolismo , Hipersensibilidad a los Alimentos/metabolismo , Absorción Intestinal , Adolescente , Adulto , Anciano , Femenino , Humanos , Lactulosa/metabolismo , Masculino , Manitol/metabolismo , Persona de Mediana Edad , PermeabilidadAsunto(s)
Hipersensibilidad a los Alimentos/inmunología , Permeabilidad de la Membrana Celular , Desensibilización Inmunológica , Relación Dosis-Respuesta Inmunológica , Hipersensibilidad a los Alimentos/diagnóstico , Hipersensibilidad a los Alimentos/fisiopatología , Humanos , Tolerancia Inmunológica , Mucosa Intestinal/fisiopatologíaRESUMEN
Gastrointestinal permeability was evaluated in 90 fasting healthy subjects and 60 patients with food allergy by oral administration to both groups of 5 g of mannitol, a marker of absorption of small molecules, and 5 g of lactulose, a marker of abnormal absorption of large molecules, and subsequent measurement of urinary excretion of mannitol and lactulose. In healthy subjects, mean 5-hour urinary excretion of mannitol was 14.11% and of lactulose 0.26%. In the fasting state, the 60 patients with food allergy exhibited a mean urinary recovery of mannitol of 13.22%, not significantly different from that in healthy subjects. Mean recovery of lactulose in the patients with food allergy was 0.55%, significantly greater than in the healthy patients. After ingestion of food allergens by the patients, mean mannitol recovery fell to 11.57% and mean recovery of lactulose rose to 1.04%, both values being significantly different from those obtained in the fasting patients. On challenging the patients after they had taken sodium cromoglycate, mean mannitol and lactulose recoveries (13.53% and 0.62%, respectively) were not significantly different from those in fasting patients but were significantly different from those obtained on challenging patients unprotected by sodium cromoglycate. Evaluation of intestinal permeability in this way provides an objective means of diagnosing food allergy and assessing the effectiveness of anti-allergic agents such as sodium cromoglycate.
Asunto(s)
Cromolin Sódico/uso terapéutico , Hipersensibilidad a los Alimentos/fisiopatología , Hipersensibilidad a los Alimentos/diagnóstico , Hipersensibilidad a los Alimentos/tratamiento farmacológico , Humanos , Absorción Intestinal , Lactulosa/metabolismo , Lactulosa/farmacocinética , Manitol/metabolismo , Manitol/farmacocinéticaRESUMEN
IgA-, IgM-, IgG- and IgE-positive plasmocytes and mast cells were counted in the fundic mucosa of two groups of rats which underwent gastroenteroanastomosis or sham operation 12 months previously. Experimentally induced duodenogastric reflux constitutes a model for biliary gastritis which is characterized by a decrease in the IgA plasmocyte count along with an increase in IgG and IgE plasmocytes and, especially, an increase in mast cells. It is suggested that this allergic-type reaction is responsible for the hyperplasia of gastric crypts seen in biliary gastritis.
Asunto(s)
Reflujo Duodenogástrico/inmunología , Mucosa Gástrica/inmunología , Mastocitos/inmunología , Células Plasmáticas/inmunología , Animales , Femenino , Gastritis Hipertrófica/inmunología , Inmunoglobulinas/metabolismo , Masculino , Ratas , Ratas EndogámicasRESUMEN
Using an animal model of gastric ulceration, in vivo and in vitro methods were developed to assess the importance of histamine in the cell turnover abnormalities previously found to occur in the preulcerous phase of gastric ulceration induced by mucosal anaphylaxis, and by using specific H1- and H2-receptor agonists and antagonists to define which receptors were involved. In ovalbumin-immunized animals, intramucosal ovalbumin injection led to a highly significant increase in cell turnover as measured by [3H]thymidine uptake (p less than 0.001). This increase was not affected by treatment with the H2 antagonist cimetidine, but was significantly reduced by the H1 antagonists promethazine and clemastine (p less than 0.01). A cell culture method was then used to examine the effects of added histamine and its antagonists. Histamine at a concentration of 10(-7) M was found to have a significant stimulatory effect on cell proliferation (p less than 0.001), and this effect was blocked by promethazine and clemastine but not by cimetidine. In contrast, histamine at a concentration of 10(-2) M had an inhibitory effect on cell proliferation which was accentuated by cimetidine and partially reversed by promethazine and clemastine. The H1 agonist betahistine was found to have stimulatory effects similar to those of histamine in low concentration (10(-7) M and 10(-6) M), but the H2 agonist 4-methyl histamine did not affect thymidine uptake at these concentrations. Both H1 and H2 agonists had a similar inhibitory effect at a concentration of 10(-2) M. It is concluded that histamine probably plays an important part in the changes in cell kinetics associated with gastric ulceration induced by this method, and that the trophic effects of histamine are mediated by H1-receptors. H2-receptors appear to have only a limited role in the control of cell proliferation.