J Korean Neurosurg Soc.  2006 Aug;40(2):103-109.

Endothelial Cell Products as a Key Player in Hypoxia-Induced Nerve Cell Injury after Stroke

• Cho CM
• Ha SU
• Bae HR
• Huh JT

Abstract

OBJECTIVE
Activated endothelial cells mediate the cascade of reactions in response to hypoxia for adaptation to the stress. It has been suggested that hypoxia, by itself, without reperfusion, can activate the endothelial cells and initiate complex responses. In this study, we investigated whether hypoxia-induced endothelial products alter the endothelial permeability and have a direct cytotoxic effect on nerve cells.
METHODS
Hypoxic condition of primary human umbilical vein endothelial cells(HUVEC) was induced by CoCl2 treatment in culture medium. Cell growth was evaluated by 3,4,5-dimethyl thiazole-3,5-diphenyl tetrazolium bromide (MTT) assay. Hypoxia-induced products (IL-1beta, TGF-beta1, IFN-gamma, TNF-alpha, IL-10, IL-6, IL-8, MCP-1 and VEGF) were assessed by enzyme-linked immunosorbent assay. Endothelial permeability was evaluated by Western blotting.
RESULTS
Prolonged hypoxia caused endothelial cells to secrete IL-6, IL-8, MCP-1 and VEGF. However, the levels of IL-1, IL-10, TNF-alpha, TGF-beta, IFN-gamma and nitric oxide remained unchanged over 48 h hypoxia. Hypoxic exposure to endothelial cells induced the time-dependent down regulation of the expression of cadherin and catenin protein. The conditioned medium taken from hypoxic HUVECs had the cytotoxic effect selectively on neuroblastoma cells, but not on astroglioma cells.
CONCLUSION
These results suggest the possibility that endothelial cell derived cytokines or other secreted products with the increased endothelial permeability might directly contribute to nerve cell injury followed by hypoxia.

Keyword

Hypoxia; Primary human umbilical vein endothelial cells; Cytokines; Endothelial permeability; Neurotoxicity

MeSH Terms

Anoxia
Astrocytoma
Blotting, Western
Culture Media, Conditioned
Cytokines
Down-Regulation
Endothelial Cells*
Enzyme-Linked Immunosorbent Assay
Humans
Interleukin-1
Interleukin-10
Interleukin-6
Interleukin-8
Neuroblastoma
Neurons*
Nitric Oxide
Permeability
Reperfusion
Stroke*
Transforming Growth Factor beta
Transforming Growth Factor beta1
Tumor Necrosis Factor-alpha
Umbilical Veins
Vascular Endothelial Growth Factor A
Culture Media, Conditioned
Cytokines
Interleukin-1
Interleukin-10
Interleukin-6
Interleukin-8
Nitric Oxide
Transforming Growth Factor beta
Transforming Growth Factor beta1
Tumor Necrosis Factor-alpha
Vascular Endothelial Growth Factor A