Development of Sentinel LN Imaging with a Combination of HAase Based on a Comprehensive Analysis of the Intra-lymphatic Kinetics of LPs

Masaki Gomi,Yu Sakurai,Takaharu Okada,Naoya Miura,Hiroki Tanaka,Hidetaka Akita

doi:10.1016/j.ymthe.2020.09.014

Masaki Gomi, Yu Sakurai + Show 4 more

Open Access

https://doi.org/10.1016/j.ymthe.2020.09.014

Copy DOI

Abstract

The sentinel lymph node (LN) is the first LN to which lymph fluid flows from tumor tissue. We identified the key parameters of liposomes (LPs) that affect their accumulation in regional (primary) LNs with minimum leakage to its connecting (secondary) LNs by a comprehensive analysis of the LN-to-LN trafficking of LPs with various surface charges and various sizes. We used a lymphatic flow-modified (LFM) mouse that allows for the chronological analysis of inguinal (primary) LN-to-axillary (secondary) LN at the body surface. As a result, the anionic medium-sized LPs (130 nm on average) exhibited the highest accumulation in the primary LNs. A mechanism-based analysis revealed that CD169-positive macrophages in LNs were the dominant cell population that captures anionic LPs. Sentinel LN imaging was also performed by the intratumoral injection of fluorescent medium-sized anionic LPs using a breast cancer orthotopic model. In comparison with the typically used contrast agent indocyanine green, the anionic LPs were detected in sentinel LNs with a high sensitivity. Additionally, the co-injection of hyaluronidase significantly improved the sensitivity of detection of the fluorescent LPs in sentinel LNs. In conclusion, medium-sized anionic LPs combined with hyaluronidase represents a potent strategy for investigating sentinel LNs.

Highlights

The lymphatic system is recognized as the third vasculature system next to arteries and veins
The findings clearly showed that, in the case of the large-sized LPs, their drainage in inguinal LN (ILN) and axillary LN (ALN) was quite poor regardless of the surface charge of LPs
The second interesting finding was that in the case of small- and middle-sized LPs, the accumulation of the cationic LPs in primary lymph node (LN) (ILNs) www.moleculartherapy.org was less than that for the neutral LPs, and that of anionic LPs was significantly higher than the corresponding values for the neutral ones

Summary

Introduction

The lymphatic system is recognized as the third vasculature system next to arteries and veins. The highly sensitive detection of sentinel LNs in surgical patients is an important technology for their efficient removal Fluorescent contrast agents such as indocyanine green (ICG) and radioactive probe are currently used to accomplish this.[5] One of the major obstacles to sentinel LN imaging is the low sentinel/non-sentinel LN fluorescent ratio and the diffusion of fluorescence dyes from the sentinel LN to surrounding tissues and its connecting LNs.[6,7] Recent papers with breast cancer patients suggest that ICG promptly flows to other tissues within a few minutes because the hydrodynamic diameter of ICG is

Methods

Results

Discussion

Conclusion