Research and Application of Kupffer Cell Thresholds for BSA Nanoparticles

Over the past decade, the dose of nanoparticles given to solid tumors has remained at a median of 0.7% of the injected dose. Most nanoparticles are trapped in a mononuclear phagocyte system (MPS), of which 85% are Kupffer cells. In our study, threshold doses of bovine serum albumin (BSA) nanoparticles were investigated for the uptake of Kupffer cells in vitro and in vivo. The antitumor effect and safety of albumin-bound paclitaxel (ABP) were improved by using threshold doses of BSA nanoparticles. We found a threshold dose of 20,000 nanoparticles per macrophage uptake in vitro and a saturation dose of 0.3 trillion nanoparticles in tumor-bearing mice. In vivo efficacy and safety evaluations demonstrated that the threshold doses of blank BSA nanoparticles could significantly improve the efficacy and safety of ABP against tumors compared with ABP alone. In this study, the delivery efficiency of ABP was improved by using blank nanoparticles to saturate Kupffer cells, which provided a new approach to studying the Kupffer cell saturation threshold and thus a new scheme for improving the curative effect of ABP.