title: Effects of Bisphosphonates on Glucose Transport in a Conditionally Immortalized Rat Retinal Capillary Endothelial Cell Line (TR-iBRB Cells).
abstract: The objective of the present study was to elucidate the effect of bisphosphonates, anti-osteoporosis agents, on glucose uptake in retinal capillary endothelial cells under normal and high glucose conditions. The change of glucose uptake by pre-treatment of bisphosphonates at the inner blood-retinal barrier (iBRB) was determined by measuring cellular uptake of [(3)H]3-O-methyl glucose (3-OMG) using a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB cells) under normal and high glucose conditions. [(3)H]3-OMG uptake was inhibited by simultaneous treatment of unlabeled D-glucose and 3-OMG as well as glucose transport inhibitor, cytochalasin B. On the other hand, simultaneous treatment of alendronate or pamidronate had no significant inhibitory effect on [(3)H]3-OMG uptake by TR-iBRB cells. Under high glucose condition of TR-iBRB cells, [(3)H]3-OMG uptake was increased at 48 h. However, [(3)H]3-OMG uptake was decreased significantly by pre-treatment of alendronate or pamidronate compared with the values for normal and high glucose conditions. Moreover, geranylgeraniol (GGOH), a mevalonate pathway intermediate, increased the uptake of [(3)H]3-OMG reduced by bisphosphonates pre-treatment. But, pre-treatment of histamine did not show significant inhibition of [(3)H]3-OMG uptake. The glucose uptake may be down regulated by inhibiting the mevalonate pathway with pre-treatment of bisphosphonates in TR-iBRB cells at high glucose condition.
authors.affiliation: College of Pharmacy and Research Center for Cell Fate Control, Sookmyung Women's University, Seoul 04310, Republic of Korea.
authors.forename: Na-Young
authors.initials: NY
authors.lastname: Lee
authors.affiliation: College of Pharmacy and Research Center for Cell Fate Control, Sookmyung Women's University, Seoul 04310, Republic of Korea.
authors.forename: Hyun-Joo
authors.initials: HJ
authors.lastname: Park
authors.affiliation: College of Pharmacy and Research Center for Cell Fate Control, Sookmyung Women's University, Seoul 04310, Republic of Korea.
authors.forename: Young-Sook
authors.initials: YS
authors.lastname: Kang
keywords: Bisphosphonates; Glucose uptake; Inner blood-retinal barrier; Mevalonate pathway; Retinal capillary endothelial cells