The underlying mechanisms governing the interactions between nanoparticles and vascular endothelial barrier remain largely unexplored, which is crucial for the optimal design of nanoparticles for clinical applications. In this study, the size-dependent interactions between calciprotein particles (CPPs) and endothelial cells (ECs) were investigated using a rat model of chronic kidney disease (CKD) induced by 5/6 nephrectomy. Two primary types of CPP1 were studied: small-sized CPP1 (S-CPP1, <
50 nm) and larger CPP1 (L-CPP1, <
100 nm), detected three and five weeks post-surgery, respectively. By adjusting the amounts of Ca