title: Vascular permeability induced by protein product of malignant brain tumors: inhibition by dexamethasone.
abstract: Serum-free conditioned medium derived from confluent monolayer cultures of malignant human astroglial tumors contains a substance that rapidly increases capillary vascular permeability after intradermal injection into guinea pigs. Accumulation of vascular permeability factor (VPF) activity occurs with increasing duration of tumor incubation in vitro. Expression of this activity is inhibited by incubation of cell cultures with cycloheximide or dexamethasone. This VPF is an acid-stable heat-labile macromolecule that is inactivated by trypsin and pepsin and binds immobilized heparin. Activity is retained by ultrafiltration with 30,000-dalton cut-off microconcentrators. Pretreatment of test animals with systemic dexamethasone prior to intradermal injection of VPF diminishes microvascular permeability. Furthermore, VPF activity is not inhibited by antihistamines. Secretion of VPF may cause the vasogenic brain edema that is frequently associated with malignant primary and metastatic intracerebral tumors. Inhibition by dexamethasone of both VPF expression in tissue culture, and VPF activity at the microvascular level in test animals, is in keeping with the known efficacy of this agent in treating the vasogenic edema associated with brain tumors.
authors: Surgical Neurology Branch, National Institute of Neurological and Communicative Disorders and Stroke, Bethesda, Maryland.
authors: J N
authors: JN
authors: Bruce
authors: G R
authors: GR
authors: Criscuolo
authors: M J
authors: MJ
authors: Merrill
authors: R R
authors: RR
authors: Moquin
authors: J B
authors: JB
authors: Blacklock
authors: E H
authors: EH
authors: Oldfield
mesh_terms: D000818:Animals; D001929:Brain Edema / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D001932:Brain Neoplasms / Q000378:metabolism* / Q000503:physiopathology; D002199:Capillary Permeability / Q000187:drug effects*; D003513:Cycloheximide / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology* / Q000627:therapeutic use; D005910:Glioma / Q000378:metabolism* / Q000503:physiopathology; D006168:Guinea Pigs; D006801:Humans; D008222:Lymphokines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D012867:Skin / Q000378:metabolism / Q000503:physiopathology; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D003907:Dexamethasone; D003513:Cycloheximide