Alteration of the neurovascular unit and the Inflammatory contribution during the encephalopathy produced by Shiga toxin 2 (STX2) from enterohemorrhagic Escherichia coli (EHEC) in the brain striatum of mice

PINTO ALIPIO; BRENER GABRIELA; CANGELOSI ADRIANA; GEOGHEGAN PATRICIA; ARENAS DAVID; GOLDSTEIN JORGE

Boston, Massachusetts

Simposio; 9th Triennial International Symposium on Shiga Toxin (Verocytotoxin)-producing Escherichia coli (VTEC) meeting; 2015

ALTERATION OF THE NEUROVASCULAR UNIT AND THE INFLAMMATORY CONTRIBUTION DURING THE ENCEPHALOPATHY PRODUCED BY SHIGA TOXIN 2 (STX2) FROM ENTEROHEMORRHAGIC ESCHERICHIA COLI (EHEC) IN THE BRAIN STRIATUM OF MICE.Alipio Pinto1*, Gabriela Brener1, Adriana Cangelosi2, Patricia Geoghegan2, David Arenas1, Jorge Goldstein1.1 Instituto de Fisiología y Biofísica "Houssay" IFIBIO, CONICET/UBA.2 Centro Nacional de Control de Calidad de Biológicos (CNCCB), ANLIS ?Dr. Carlos G. Malbrán?.*Presenting author: A. Pinto (pintoalipio@gmail.com)Introduction: The striatum is involved in central motor pathways and is frequently affected in patients infected with EHEC. In addition to Stx2, LPS is secreted by the bacteria and may also contribute to the observed striatal dysfunction. The aim of this study was to determine: i) whether LPS exacerbates the deleterious effect of Stx2 in the neurovascular unit (NU) of the striatum, and ii) the existence of a proinflammatory component that contributes to the clinical signs. Methods: NIH male mice were injected intravenously with Stx2+LPS or Stx2 or LPS or vehicle (control). In addition the same described groups were treated with Dexamethasone. Mice were intracardially perfused with a fixative solution or with the addition of Evans Blue, to test the blood brain barrier (BBB) permeability. Their brains were subjected to immunofluorescence with lectins to identify the microvasculature, anti-VEGF, anti-GFAP to identify astrocytes and anti-Stx2. Results and Discussion: Stx2+LPS maximally increased the permeability of the BBB (79+5 in arbitrary units [AU]), increased the expression levels of GFAP (32+5 AU), and decreased completely the expression levels of VEGF (63+5 positive particles) in comparison to controls. Immunopositive cells for Stx2 were higher in Stx2+LPS treated mice than Stx2 alone (80+6). Dexamethasone significantly reduced the permeability of the BBB in Stx2+LPS treated mice and partially reverted the damage on the microvasculature and the changes observed in the expression of VEGF, GFAP, and immunopositive Stx2 cells (P