J774A.1 cell studies demonstrate uptake of paramagnetic and fluorescent HDL by macrophages in vitro.
J774A.1 macrophages were incubated for 2 h at 37°C with medium only or with medium containing 2.0 μM (as calculated for Rhodamine B) paramagnetic and Rhodamine B-labeled discoidal HDL (dHDL) or spherical HDL (sHDL) synthesized using a 1:1 mixture of oxidized synthetic apo A-I peptides H4 and H6. (A) Fluorescence intensities of cell lysates were measured and normalized to total cell protein content (mean ± SD, n = 3). (B) Loosely packed cell pellets were generated and T1 values were measured using T1-weighted MR imaging. Shown in the inset are T1-weighted images of cell pellets incubated with medium alone (M), dHDL (D) or sHDL (S). (C) Normalized enhancement ratio (NER) values for cell pellets are calculated from corresponding T1-weighted images and are relative to cells incubated with medium only. (D) Contrast-to-noise ratio (CNR) values for cell pellets are calculated from the corresponding T1-weighted images and are relative to cells incubated with medium only.
