RESUMO
Neoblasts are totipotent cells, solely responsible for the proliferation and maturation of tissues in free-living flatworms. Similar cells have been isolated from parasitic flatworms such as Echinococcus. Taenia solium causes human taeniasis (intestinal) and cysticercosis in humans and pigs. Brain infection with larvae (cysts) of T. solium results in neurocysticercosis which is hyperendemic in Peru, and its treatment is associated with serious neurological symptoms. The proliferative capacity and development stages of T. solium have not been described and the neoblasts of this parasite have not been characterized We looked for cell proliferation in T. solium cysts collected from an infected pig, which were identified when replicating and incorporating bromodeoxyuridine nucleotide detected with a monoclonal antibody. A stable cell line of neoblasts would be useful for systematic in vitro studies on drug efficacy and the biology of T. solium.
Assuntos
Cysticercus/citologia , Taenia solium/citologia , Animais , Proliferação de CélulasRESUMO
No existen, hasta el momento, imágenes que muestren la disposición de la citoarquitectura de parásitos adultos de Taenia solium, parásitos los cuales se encuentran en el intestino de portadores humanos asintomáticos. Las causas de ello podrían tener como base el que cuando se recuperan los parásitos, ellos han sufrido alteraciones debidas a la respuesta inmune de sus hospederos o bien, por el efecto que han producido en los parásitos los fármacos antihelmínticos que hayan sido usados en el tratamiento de los pacientes. Una de las alternativas que se han encontrado para la obtención de parásitos adultos, es la obtención de tenias a partir del modelo de teniosis experimental en hámsteres dorados e inmunosuprimidos y que gracias a este modelo se han podido efectuar diferentes tipos de estudios de los parásitos de esta fase infectiva. El propósito de este reporte es presentar imágenes de ultraestructura, obtenidas mediante Microscopía Electrónica de Barrido, de un corte transversal obtenido de un proglótido de una tenia recuperada de una infección experimental. Las imágenes se obtuvieron a diferentes aumentos y muestran aspectos relacionados con la superficie tegumentaria, el tegumento sincicial continuo, la capa germinal que incluye el soma de algunas células subtegumentarias y los ductos del sistema protonefridial tanto vacíos como llenos con corpúsculos calcáreos. Las imágenes ultraestructurales obtenidas muestran una forma de observación de la anatomía microscopica de los parásitos en estudio y ello contribuye a ampliar el conocimiento de los mismos en relación a aspectos de su biología celular y su fisiología.
There are no clear morphological evidences of the cytoarchitecture of intestinal adult tapeworms of Taenia solium recovered from infected humans. Parasites could be altered because of the host´s immunological response or by the direct action of drugs used for antihelminthic treatment. Experimental taeniosis in immunosuppressed golden hamsters is a useful way for recovering and studying adult parasites. The purpose of this report is to show images, taken at the ultrastructural level by Scanning Electron Microscopy (SEM), of a cross-sectioned strobilar chain from an adult tapeworm. The parasite was recovered from an experimental infection. Images were taken at several magnifications; they show the brush border tegumental surface, the syncytial tegument, the germinal layer, some cell bodies and the protonephridial system ducts: empty or filled with calcareous corpuscles. Ultrastructural images taken using SEM of T. solium adult parasites, recovered from experimental infections, could be a new way for observing the microscopic anatomy of these parasites and for increasing the knowledge of aspects related to their cellular biology and physiology.
Assuntos
Animais , Taenia solium/anatomia & histologia , Taenia solium/citologia , Taenia solium/microbiologia , Taenia solium/parasitologia , Taenia solium/ultraestrutura , Microscopia Eletrônica de Varredura/métodosRESUMO
The existence of latent Taenia solium post-oncospheral stages in the tissues of infected pigs has been postulated. To assess whether such structures exist and can be detected, we examined muscle samples from cysticercosis-infected and uninfected pigs. Pork samples were homogenized, centrifuged, and resuspended in saline solution. Round microscopic structures of approximately 10 microm with variable refringence were found in the pellets of all samples from both infected and uninfected pigs. These became homogeneously red after staining with Sudan IV and disappeared after ether extraction. The only difference between samples from infected and uninfected pigs was the presence of inflammatory cells and tissue necrosis debris in the former group. Taenia solium oncospheres were stained and observed for comparative purposes, before and after inoculation into pork. Control oncospheres were ellipsoidal, had nucleated basophile cells in their interior, and showed red aggregates on their surfaces when stained with 3% Sudan IV. While rounded microscopical structures similar to those previously reported were found, these differed morphologically from oncospheres, were of a lipid nature, and occurred in both infected and uninfected animals. No evidence supporting the presence of latent post-oncospheral stages of Taenia solium was generated in this series of experiments.
Assuntos
Cisticercose/veterinária , Músculo Esquelético/parasitologia , Sus scrofa/parasitologia , Doenças dos Suínos/parasitologia , Taenia solium/isolamento & purificação , Animais , Centrifugação com Gradiente de Concentração , Cisticercose/parasitologia , Cisticercose/patologia , Feminino , Estágios do Ciclo de Vida/fisiologia , Masculino , Doenças dos Suínos/patologia , Taenia solium/citologia , Fatores de TempoRESUMO
Taenia solium cysticerci infect human beings and pigs, causing cysticercosis. In this study the pig was used as a model to characterize the immune response against cysticerci, given the difficulties in analysing the developing immune response in infected human brains. Metacestodes in different stages of viability or degeneration were isolated from the brain, heart and skeletal muscle of naturally infected swine, and the adjacent tissue was examined histologically. The immune response elicited by the cysticerci was classified into four separate stages. In stage I the parasites were surrounded by a thin layer of collagen type I, and by stage II there was a sparse inflammatory infiltrate. In stage III, granuloma formation was evident, and by stage IV the parasite was surrounded by an eosinophil-rich infiltrate and its vesicular membrane had begun to degenerate. The final stage, IV, was detected mainly in the heart but not in the brain. The granulomatous reaction in swine resembled that described previously in human patients, but differed in the abundance of eosinophils, the relative paucity of plasma cells, and the discrete deposition of collagen. These differences were probably due to the fact that in pigs the immune response can be examined earlier than in human patients, in whom sampling is inevitably made at a more chronic stage.