[Downregulation of the pigment epithelium derived factor by hypoxia and elevated glucose concentration in cultured human retinal pigment epithelial cells].
OBJECTIVE
To explore the effect of hypoxia and high glucose concentration on the production and secretion of vascular endothelial growth factor (VEGF) and pigment epithelium derived factor (PEDF), an antiangiogenesis factor, in the cultured human retinal pigment epithelium (RPE) cells.


METHODS
Human RPE cells were cultured under normoxic or hypoxic (1% O(2)) condition with or without (25 mmol/L) glucose. RT-PCR and real-time quantificaton analysis were used to examine the expression of VEGF and of PEDF mRNAs. Western blot analysis was used to measure the levels of VEGF and PEDF proteins.


RESULTS
The expression of VEGF mRNA in RPE cells under hypoxic condition for 12 hours was 2.6 times that under the normoxic condition (P = 0.001), and the expression of PEDF mRNA was only 0.77 time that of the controls (P = 0.251). Under hypoxic condition with high concentration of glucose the expression of VEGF mRNA in RPE cells was 3.8 times that under the normoxic condition (P < 0.001), and the expression of PEDF mRNA was further decreased (only 0.23 time that of the controls, P = 0.02). The expression levels of VEGF protein under hypoxic condition with and without glucose were 1.69 and 1.27 times respectively those under the normoxic condition (P < 0.0001 and P = 0.004). The expression level of PEDF protein under hypoxic condition with glucose was 0.49 time that under the normoxic condition (P < 0.0001) and the expression level of PEDF protein under hypoxic condition without glucose was 0.92 time that under the normoxic condition (P = 0.114).


CONCLUSIONS
Hypoxia indirectly influence the downregulation of PEDF and high concentration of glucose directly downregulates the expression of PEDF and increases the expression of VEGF simultaneously, thus supporting the concept that hyperglycemia is one of the most dangerous consequences of diabetes-associated "glucose toxicity" in vivo.
Yao
Yi
Y
Department of Ophthalmology, Chinese PLA General Hospital. Beijing 100853, China.
Guan
Ming
M
Zhao
Xiu-qin
XQ
Huang
Yi-fei
YF
D015153:Blotting, Western; D015687:Cell Hypoxia; D002478:Cells, Cultured; D015536:Down-Regulation; D005136:Eye Proteins; D005786:Gene Expression Regulation; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D009414:Nerve Growth Factors; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D015843:Serpins / Q000235:genetics*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics; D000099174:Pigment Epithelium-Derived Factor
D005136:Eye Proteins; D005947:Glucose; D009414:Nerve Growth Factors; D011506:Proteins; D012333:RNA, Messenger; D015843:Serpins; D042461:Vascular Endothelial Growth Factor A; D000099174:Pigment Epithelium-Derived Factor