Examining glucose transport in single vascular smooth muscle cells with a fluorescent glucose analog

Changes in vascular smooth muscle glucose transport are thought to contribu te to the pathogenesis of vascular disease in conditions such as diabetes, yet no single-cell assay for glucose uptake by VSM exists. Therefore, we ex amined the uptake of the fluorescent glucose analog 2-[N-(7-nitrobenz-2-oxa -1,3-diazol-4-yl)amino]-2-deoxyglucose (2-NBDG) in isolated pig vascular sm ooth muscle cells (VSMC) using digital imaging microscopy. Uptake of 2-NBDG by VSMC was inhibited by D-glucose but not by L-glucose, suggesting that 2 -NBDG enters VSMC via glucose transporters. Uptake of 2-NBDG was linear in the presence of 10 mM D-glucose (n=6, R-2=0.9408) but not in its absence (n =4, R-2=0.9993), indicating that 2-NBDG is not metabolized and accumulates within the cells. 2-NBDG fluorescence in VSMC was often non-uniform and app eared to represent binding of 2-NBDG to some cytoplasmic component. The pre sent study demonstrates that 2-NBDG is a useful tool for examining vascular smooth muscle glucose uptake at the single cell level.