Biodistribution and imaging studies of 67Ga-labeled liposomes in rabbits with a vascular injury

Innate immunity and inflammation are of major importance in vascular repair. Monocytes and neutrophils adhesion and infiltration occur immediately after vascular injury. We hypothesized that the systemic inflammatory state following vascular injury would result in altered biodistribution of the administered liposomes. The purpose of this study was to assess the biodistribution of liposomes in intact and balloon-injured rabbit carotid arteries. Real-time imaging, single photon emission computed tomography (SPECT) and dynamic tomography were used to evaluate the dynamic biodistribution. In addition, γ-counter scintigraphy of organ explants was used. Increased accumulation of liposomes was observed in the liver and spleen. Furthermore, a significantly higher concentration of liposomes was observed in the injured carotid in comparison to the intact artery, 0.091 ± 0.040% and 0.033 ± 0.016%, 24 h post-injection, respectively. Our findings emphasize the importance of assessing the distribution of drug and liposomal formulations under pathological conditions which are associated with an inflammatory process.