The Effects of Bisphosphonates on Taurine Transport in Retinal Capillary Endothelial Cells Under High Glucose Conditions - Advances in Experimental Medicine and Biology - page 59

100

*

*

50

0

0 8 16 24 32 40 48

Pre-incubation time (h)

Fig. 7.1 Time-course of the effect of high glucose on [ 3 H]taurine uptake by TR-iBRB cells.
25 mM glucose was pre-incubated for the time period in the figure. The cells were incubated for
5 min at 37°C with ECF buffer containing [ 3 H]taurine (28 nM). Each point represents the
mean ± SEM ( n = 3-4). * p < 0.05, signi fi cantly different from time 0

7.3.2 Effect of Bisphosphonates on the [ 3 H]Taurine Uptake

in TR-iBRB Cells Under High Glucose Condition

It has been suggested that bisphosphonates such as alendronate and pamidronate
have anti-angiogenic effects by inhibiting upregulation of VEGF in the diabetic
retina (Yokota et al. 2007 ). We investigated the change of [ 3 H]taurine uptake by
bisphosphonates in TR-iBRB cells under high glucose condition. Under exposing
TR-iBRB cells to 25 mM glucose for 48 h, TR-iBRB cells were exposed to 10 m M
alendronate and 10 mM pamidronate for 0.5, 4, and 6 h. As shown in Fig. 7.2 , [ 3 H]
taurine uptake was increased significantly by pretreatment of alendronate and
pamidronate compared with the values for 25 mM glucose.

7.3.3 Effect of Mevalonate Pathway Intermediate,

Geranylgeraniol on the [ 3 H]Taurine Uptake
in TR-iBRB Cells Under High Glucose Condition

Increased [ 3 H]taurine uptake by pretreatment of alendronate and pamidronate was
significantly reduced by mevalonate pathway intermediates, GGOH (10 mM) (Fig. 7.3 ).