Endothelium serves a vital homeostatic function by preserving the fluidity of blood and preventing escape of blood constituents from the intravascular space. This proposal examines the effects of hypoxia on endothelial cell coagulant and barrier function. Preliminary studies indicate that hypoxia down-regulates two endothelial cell anticoagulant properties, fibrinolysis and the protein C/protein S pathway. The mechanisms underlying these observations will be investigated, as well as the effects of hypoxia to modulate other endothelial coagulant functions. Because hypoxia also appears to perturb endothelial monolayer barrier properties, the integrity of the monolayer under hypoxic conditions will be determined by examining permeability to a variety of macromolecules and lower molecular weight solutes. Permeability changes will be correlated with changes in cell morphology (shape, cytoskeleton and junctions). A hypoxic vascular microenvironment occurs in the setting of a variety of diseases in{ which host response mediators, such as norepinephrine and TNF, are elaborated. Studies will examine the endothelial cell response to these agents in hypoxia. Preliminary data indicating that the number of endothelial alpha1-adrenergic receptors and an alpha1-adrenergic response increases following hypoxic exposure provide a rationale for performing a detailed examination of transduction proteins and effector mechanisms (phosphoinositide hydrolysis, calcium mobilization, eicosanoid production) activated by alpha1-adrenergic receptors and the role of these intracellular signalling mechanisms in the control of cellular coagulant and barrier function. Similar studies investigating the effect of TNF on endothelial cell function, the cellular mechanisms involved and their modulation by hypoxia are proposed. Exposure of cultured cells to low levels of oxygen increases the rate of synthesis of a specific class of oxygen-regulated proteins. Our preliminary data indicate that endothelium labelled metabolically with 35S-methionine and exposed to low concentrations oxygen demonstrates new/enhanced bands on autoradiograms from SDS- PAGE of culture supernatants and lysates. The final objective of this proposal is to produce monoclonal antibodies relatively selective for hypoxic endothelium. These immunologic reagents will be used to characterize the evolution of the hypoxic state in vitro and, in the future, hypoxic vascular injury in vivo These specific plans are directed toward our long-term objective: understanding the role of endothelium in the pathogenesis of vascular injury.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
Project #
Application #
Study Section
Pathology A Study Section (PTHA)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Columbia University (N.Y.)
Schools of Medicine
New York
United States
Zip Code
Imuta, Naohiko; Hori, Osamu; Kitao, Yasuko et al. (2007) Hypoxia-mediated induction of heme oxygenase type I and carbon monoxide release from astrocytes protects nearby cerebral neurons from hypoxia-mediated apoptosis. Antioxid Redox Signal 9:543-52
Yan, S F; Lu, J; Zou, Y S et al. (2000) Protein kinase C-beta and oxygen deprivation. A novel Egr-1-dependent pathway for fibrin deposition in hypoxemic vasculature. J Biol Chem 275:11921-8
Maruyama, S; Cantu 3rd, E; Galili, U et al. (2000) alpha-galactosyl epitopes on glycoproteins of porcine renal extracellular matrix. Kidney Int 57:655-63
Biancone, L; Cantaluppi, V; Segoloni, G et al. (2000) Role of platelet-activating factor in functional alterations induced by xenoreactive antibodies in porcine endothelial cells. Transplantation 70:1198-205
Maruyama, S; Cantu 3rd, E; DeMartino, C et al. (1999) Interaction of baboon anti-alpha-galactosyl antibody with pig tissues. Am J Pathol 155:1635-49
Yan, S F; Lu, J; Zou, Y S et al. (1999) Hypoxia-associated induction of early growth response-1 gene expression. J Biol Chem 274:15030-40
Maruyama, S; Cantu 3rd, E; Demartino, C et al. (1999) Membranous glomerulonephritis induced in the pig by antibody to angiotensin-converting enzyme: considerations on its relevance to the pathogenesis of human idiopathic membranous glomerulonephritis. J Am Soc Nephrol 10:2102-8
Maruyama, S; Cantu E3rd; Pernis, B et al. (1999) Alpha-galactosyl antibody redistributes alpha-galactosyl at the surface of pig blood and endothelial cells. Transpl Immunol 7:101-6
Niitsu, Y; Hori, O; Yamaguchi, A et al. (1999) Exposure of cultured primary rat astrocytes to hypoxia results in intracellular glucose depletion and induction of glycolytic enzymes. Brain Res Mol Brain Res 74:26-34
Yan, S F; Zou, Y S; Gao, Y et al. (1998) Tissue factor transcription driven by Egr-1 is a critical mechanism of murine pulmonary fibrin deposition in hypoxia. Proc Natl Acad Sci U S A 95:8298-303

Showing the most recent 10 out of 57 publications