A human astrocytoma cell line is highly susceptible to infection with Trypanosoma cruzi

Astrocytes play a vital role in neuronal protection, homeostasis, vascular interchange and the local immune response. Some viruses and parasites can cross the blood-brain barrier and infect glia. Trypanosoma cruzi, the aetiological agent of Chagas disease, can seriously compromise the central nervous system, mainly in immune-suppressed individuals, but also during the acute phase of the infection. In this report, the infective capacity of T. cruzi in a human astrocyte tumour-derived cell line was studied. Astrocytes exposed to trypomastigotes (1:10 ratio) produced intracellular amastigotes and new trypomastigotes emerged by day 4 post-infection (p.i.). At day 6 p.i., 93% of the cells were infected. Using flow cytometry, changes were observed in both the expression of major histocompatibility complex class I and II molecules and the chemokine secretion pattern of astrocytes exposed to the parasite. Blocking the low-density lipoprotein receptor on astrocytes did not reduce parasite intracellular infection. Thus, T. cruzi can infect astrocytes and modulate the immune response during central nervous system infection.

Bases moleculares de la Neuroinmunología (I): barrera sangre-líquido cefalorraquídeo y síntesis intratecal de inmunoglobulinas / Molecular bases of neuroimmunology (I): blood-cerebrospinal fluid barrier and intrathecal synthesis of immunoglobulins

La Neuroinmunología surge como disciplina en las últimas décadas del pasado siglo, a partir del desarrollo de las ciencias matrices. Para comprender las bases moleculares de estas ciencias es necesario conocer los conceptos actuales de barrera hematoencefálica y síntesis intratecal de inmunoglobulinas. La barrera hematoencefálica es un equilibrio físico-químico de transporte bidireccional restringido, donde las moléculas se difunden de acuerdo con su masa molecular. Existen proteínas que se difunden de la sangre al líquido cefalorraquídeo y otras se sintetizan en éste. Las inmunoglobulinas se difunden hacia el líquido cefalorraquídeo y se sintetizan en él. Para discriminar la síntesis intratecal de éstas se emplean diversas fórmulas, entre las que se encuentran las de Link, Tourtellotte, Schuller y Reiber

Inflammatory response of the spinal cord to multiple episodes of blood-brain barrier disruption and toxic demyelination in Wistar rats

Multiple episodes of blood-brain barrier disruption were induced by sequential intraspinal injections of ethidium bromide. In addition to the barrier disruption, there was toxic demyelination and exposure of myelin components to the immune system. Twenty-seven 3-month-old Wistar rats received 2, 3 or 4 injections of 1 mul of either 0.1 percent ethidium bromide in normal saline (19 rats) or 0.9 percent saline (8 rats) at different levels of the spinal cord. The time intervals between the injections ranged from 28 to 42 days. Ten days after the last injection, all rats were perfused with 2.5 percent glutaraldehyde. The spinal sections were evaluated macroscopically and by light and transmission electron microscopy. All the lesions demonstrated a mononuclear phagocytic infiltrate apparently removing myelin. Lymphocytes were not conspicuos and were found in only 34 percent of the lesions. No perivascular cuffings were detected. In older lesions (38 days and older) they were found only within Virchow-Robin spaces. This result suggests that multiple blood-brain barrier disruptions with demyelination and exposure of myelin components to the immune system were not sufficient to induce an immune-mediated reaction in the central nervous system.

Imunologia na esclerose múltipla / Immunolgy in multiple sclerosis

A patogênese e a etiologia da esclerose múltipla (EM) é desconhecida. A EM é adquirida por indivíduos geneticamente susceptíveis. A doença se desenvolve devido à quebra da impermeabilidade da barreira hematoencefálica. Esta alteraçäo causa edema e inflamaçäo. O papel do sistema imune e, em particular, dos linfócitos T é revisto

Permeabilidad de la barrera hematoencefálica al magnesio magnesio en preeclampsia

Objetivo: Determinar si el magnesio cruza la barrera hematoencefálica en pacientes con preeclampsia. Material y Métodos: Se seleccionaron 41 embarazadas, 20 con preeclampsia(grupo de estudio) y 21 sin preeclampsia (grupo control). El grupo con preeclampsia recibió sulfato de magnesio en bolo inicial de 4 gr vía intravenosa y 1 gr/hora en dosis de mantenimiento. El grupo control no recibió sulfato de magnesio. A todas las pacientes se les practicó operación de cesárea(por indicación obstétrica) y se les recolectó 1 cm3 de líquido cefalorraquídeo en el momento de la punción espinal para la anestesia regional. Se mostraron además muestras de sangre periférica basal y 2 horas después. En todas las muestras se midió concentración de magnesio. Lo cual se hizo de menera ciega por uno de los investigadores. Resultados: Los niveles de magnesio en líquido cefalorraquídeo no fueron significativamente diferentes entre los dos grupos 4.88 mEq/L (grupo control) y 5.58 mEq/L (grupo estudio) (p=0.29). En contraste, los niveles séricos de magnesio fueron significativamente más altos en el grupo con preeclampsia(5.91 mEq/L) que en el grupo control (4.27 mEq/L) (p menor 0.003). Conclusiones: La barrera hematoencefálica parece no ser permeable al paso del ión magnesio en la preeclampsia