The role of polyol pathway in high glucose-induced endothelial cell damages.
To clarify the mechanism by which hyperglycemia in diabetes mellitus causes endothelial cell damages, the effects of high glucose on DNA fragmentation and caspase-3 activity of cultured endothelial cells and on the generation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) were studied. Furthermore, the involvement of the polyol pathway in this process was investigated using aldose reductase inhibitor (SNK-860). Human umbilical vein endothelial cells (HUVECs) were incubated with 5.5mmol/L (low glucose medium) or 28mmol/L (high glucose medium) of glucose. The amounts of fragmented DNA, caspase-3 activity and 8-OHdG in the medium increased in significantly greater extent in high glucose-incubated HUVECs than in low glucose-incubated HUVECs. No significant increase in fragmented DNA or 8-OHdG was observed when HUVECs were incubated with mannitol (500mg/mL). The concentration of intracellular sorbitol was significantly higher in HUVECs incubated in high glucose medium than that in low glucose medium. Addition of the aldose reductase inhibitor SNK-860 dose-dependently decreased the intracellular sorbitol concentration in HUVECs incubated in high glucose medium, and also significantly suppressed the increases in fragmented DNA, caspase-3 activity and 8-OHdG by conditioning with high glucose medium. These results suggest that high glucose-induced endothelial cell damages may be mediated by activation of the polyol pathway accompanied by augmented oxidative stress.
Oyama
Tomokazu
T
Center of Diabetes, Endocrine and Metabolism, Sakura Hospital, School of Medicine, Toho University, 564-1 Shimoshizu, Sakura-City, Chiba, Japan.
Miyasita
Yoh
Y
Watanabe
Husako
H
Shirai
Kohji
K
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism; D050260:Carbohydrate Metabolism / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D003470:Culture Media / Q000494:pharmacology; D053938:DNA Fragmentation / Q000187:drug effects; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology*; D006801:Humans; D048289:Imidazolidines / Q000494:pharmacology; D011108:Polymers / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013012:Sorbitol / Q000378:metabolism
D003470:Culture Media; D048289:Imidazolidines; D011108:Polymers; C024617:polyol; D013012:Sorbitol; D000080242:8-Hydroxy-2'-Deoxyguanosine; C077139:fidarestat; D000449:Aldehyde Reductase; D053148:Caspase 3; D003849:Deoxyguanosine; D005947:Glucose