Size-dependent Nanoparticle Accumulation In Venous Malformations

The current treatment of venous malformations (VMs) consists of medications with systemic toxicity and procedural interventions with high technical difficulty and risk of hemorrhage. Using nanoparticles (NPs) to enhance drug delivery to VMs could enhance efficacy and decrease systemic toxicity. NPs can accumulate in tissues with abnormal vasculature, a concept known as the enhanced permeation and retention (EPR) effect. EPR has been documented in tumors, bioengineered vessels, and VMs. However, in VMs, it is unknown if NP size affects EPR and if so, which particle size improves NP accumulation.

In this study, we used a murine model of subcutaneous VMs using human umbilical vein endothelial cells that express the most frequent VM-causing tyrosine kinase with immunoglobulin and EGF homology domains mutation, tyrosine kinase with immunoglobulin and EGF homology domains-L914F. Hollow silica NPs coated in polyethylene glycol (PEG) and conjugated to a fluorophore were administered systemically via tail vein injection. We studied the accumulation of a range of NP sizes within the VM and organs using confocal microscopy and an in vivo imaging system.

The 20, 50, 80, and 180 nm PEGylated, fluorophore-tagged hollow silica NPs were spherical and had hydrodynamic diameters of 31.6 ± 0.9, 58.5 ± 0.1, 87.1 ± 2.4, and 232 ± 1.26 nm, respectively. Following systemic NP administration, 20 nm NPs had 2 times more fluorescence accumulation within VMs compared with 50 nm, and 6 times more fluorescence accumulation compared with larger (greater than 80 nm) NPs (P < .01).

This study helps to determine the optimal NP size for passive accumulation within VMs and lays the foundation for engineering NPs for the treatment of VMs.