title: Evans blue staining reveals vascular leakage associated with focal areas of host-parasite interaction in brains of pigs infected with Taenia solium.
abstract: Cysticidal drug treatment of viable Taenia solium brain parenchymal cysts leads to an acute pericystic host inflammatory response and blood brain barrier breakdown (BBB), commonly resulting in seizures. Naturally infected pigs, untreated or treated one time with praziquantel were sacrificed at 48 hr and 120 hr following the injection of Evans blue (EB) to assess the effect of treatment on larval parasites and surrounding tissue. Examination of harvested non encapsulated muscle cysts unexpectedly revealed one or more small, focal round region(s) of Evans blue dye infiltration (REBI) on the surface of otherwise non dye-stained muscle cysts. Histopathological analysis of REBI revealed focal areas of eosinophil-rich inflammatory infiltrates that migrated from the capsule into the tegument and internal structures of the parasite. In addition some encapsulated brain cysts, in which the presence of REBI could not be directly assessed, showed histopathology identical to that of the REBI. Muscle cysts with REBI were more frequent in pigs that had received praziquantel (6.6% of 3736 cysts; n = 6 pigs) than in those that were untreated (0.2% of 3172 cysts; n = 2 pigs). Similar results were found in the brain, where 20.7% of 29 cysts showed histopathology identical to muscle REBI cysts in praziquantel-treated pigs compared to the 4.3% of 47 cysts in untreated pigs. Closer examination of REBI infiltrates showed that EB was taken up only by eosinophils, a major component of the cellular infiltrates, which likely explains persistence of EB in the REBI. REBI likely represent early damaging host responses to T. solium cysts and highlight the focal nature of this initial host response and the importance of eosinophils at sites of host-parasite interaction. These findings suggest new avenues for immunomodulation to reduce inflammatory side effects of anthelmintic therapy.
authors.affiliation: Laboratory of Immunopathology in Neurocysticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Miguel
authors.initials: M
authors.lastname: Marzal
authors.affiliation: Laboratory of Immunopathology in Neurocysticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Cristina
authors.initials: C
authors.lastname: Guerra-Giraldez
authors.affiliation: Laboratory of Immunopathology in Neurocysticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Adriana
authors.initials: A
authors.lastname: Paredes
authors.affiliation: Laboratory of Immunopathology in Neurocysticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Carla
authors.initials: C
authors.lastname: Cangalaya
authors.affiliation: Laboratory of Immunopathology in Neurocysticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.
authors.forename: Andrea
authors.initials: A
authors.lastname: Rivera
authors.affiliation: Facultad de Medicina Veterinaria, Universidad Nacional Mayor de San Marcos, Lima, Peru.
authors.forename: Armando E
authors.initials: AE
authors.lastname: Gonzalez
authors.affiliation: Laboratory of Immunopathology in Neurocysticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru; National Institutes of Allergy and Infections Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Siddhartha
authors.initials: S
authors.lastname: Mahanty
authors.affiliation: Laboratory of Immunopathology in Neurocysticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru; Instituto Nacional de Ciencias Neurológicas, Lima, Peru.
authors.forename: Hector H
authors.initials: HH
authors.lastname: Garcia
authors.affiliation: Laboratory of Immunopathology in Neurocysticercosis, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru; National Institutes of Allergy and Infections Diseases, National Institutes of Health, Bethesda, Maryland, United States of America.
authors.forename: Theodore E
authors.initials: TE
authors.lastname: Nash
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000469:parasitology* / Q000473:pathology; D005070:Evans Blue / Q000493:pharmacokinetics; D006790:Host-Parasite Interactions; D011223:Praziquantel / Q000627:therapeutic use; D013552:Swine; D041201:Taenia solium / Q000472:pathogenicity; D013622:Taeniasis / Q000188:drug therapy / Q000662:veterinary*
chemical_list: D005070:Evans Blue; D011223:Praziquantel