title: Blood-brain barrier disruption and oxidative stress in guinea pig after systemic exposure to modified cell-free hemoglobin.
abstract: Systemic exposure to cell-free hemoglobin (Hb) or its breakdown products after hemolysis or with the use of Hb-based oxygen therapeutics may alter the function and integrity of the blood-brain barrier. Using a guinea pig exchange transfusion model, we investigated the effect of a polymerized cell-free Hb (HbG) on the expression of endothelial tight junction proteins (zonula occludens 1, claudin-5, and occludin), astrocyte activation, IgG extravasation, heme oxygenase (HO), iron deposition, oxidative end products (4-hydroxynonenal adducts and 8-hydroxydeoxyguanosine), and apoptosis (cleaved caspase 3). Reduced zonula occludens 1 expression was observed after HbG transfusion as evidenced by Western blot and confocal microscopy. Claudin-5 distribution was altered in small- to medium-sized vessels. However, total expression of claudin-5 and occludin remained unchanged except for a notable increase in occludin 72 hours after HbG transfusion. HbG-transfused animals also showed increased astrocytic glial fibrillary acidic protein expression and IgG extravasation after 72 hours. Increased HO activity and HO-1 expression with prominent enhancement of HO-1 immunoreactivity in CD163-expressing perivascular cells and infiltrating monocytes/macrophages were also observed. Consistent with oxidative stress, HbG increased iron deposition, 4-hydroxynonenal and 8-hydroxydeoxyguanosine immunoreactivity, and cleaved caspase-3 expression. Systemic exposure to an extracellular Hb triggers blood-brain barrier disruption and oxidative stress, which may have important implications for the use of Hb-based therapeutics and may provide indirect insight on the central nervous system vasculopathies associated with excessive hemolysis.
authors.affiliation: Laboratory of Biochemistry and Vascular Biology, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA.
authors.forename: Omer I
authors.initials: OI
authors.lastname: Butt
authors.forename: Paul W
authors.initials: PW
authors.lastname: Buehler
authors.forename: Felice
authors.initials: F
authors.lastname: D'Agnillo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001253:Astrocytes / Q000187:drug effects / Q000473:pathology; D001803:Blood Transfusion; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000201:enzymology / Q000473:pathology*; D053148:Caspase 3 / Q000378:metabolism; D002474:Cell-Free System / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006168:Guinea Pigs; D006418:Heme / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis; D006454:Hemoglobins / Q000008:administration & dosage* / Q000494:pharmacology*; D007074:Immunoglobulin G / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism
chemical_list: D005904:Glial Fibrillary Acidic Protein; D006454:Hemoglobins; D007074:Immunoglobulin G; D008565:Membrane Proteins; D006418:Heme; D007501:Iron; D006419:Heme Oxygenase (Decyclizing); D053148:Caspase 3