Technical Review: Cellular and Noncellular Influences on Lipid Nanoparticle Tropism In the Liver
- perryt6
- Sep 24
- 3 min read
Author: Mario Yomir Mata Corral
Advisor: Wilson Poon
Affiliation: University of Texas at El Paso, El Paso, Texas, USA
Background Introduction
Hepatocellular carcinoma (HCC) represents the second leading cause of cancer-related mortality worldwide, claiming over 700,000 lives annually. The liver's central role in blood filtration and metabolism makes it an attractive target for drug delivery, with lipid nanoparticles (LNPs) showing particular promise due to their natural hepatic tropism. However, LNP efficacy becomes compromised in HCC environments due to inadequate understanding of liver physiology under cancerous conditions.
Current therapeutic options for liver cancer, including partial hepatectomy, liver transplantation, ablation therapy, and embolization, face significant limitations. Many patients with HCC also suffer from cirrhosis, restricting surgical eligibility. The shortage of donor organs further compounds treatment challenges, with only approximately 6,000 transplants performed annually among 17,500 patients on waiting lists. These constraints underscore the urgent need for more effective and targeted therapeutic strategies.
Materials and Methodology
The researchers first developed SPARKLE-tagged LNPs compatible with tissue clearing techniques. Briefly, a lipid formulation was optimized for peptide conjugation with a custom CK7 peptide sequence, and LNPs were produced both with automatic pipetting and microfluidic mixing. LNPs from both methods were characterized and eventually administered to mice. A pilot study first compared SPARKLE LNPs to a PBS control, while a subsequent high fat diet (HFD) study examined their efficacy in mice affected by fatty liver disease. Organs were collected at set intervals post-injection and fixed for visualization using a CLARITY tissue clearing protocol.
Results
LNP Synthesis Optimization
The transition from microfluidic to pipetting robot-based synthesis yielded significant improvements in scalability. While the early screening microfluidic system exhibited similar performance, its low production volume limited translation to the murine model. Eight pipetting robot batches were successfully combined to produce 1.6 mL of LNP solution with final measurements of 131.9 nm size and 0.167 PDI, both within acceptable quality control parameters. This optimization enabled consistent batch production for animal studies while maintaining particle uniformity.
SPARKLE-LNP Compatibility Validation
The pilot study successfully demonstrated SPARKLE-LNP compatibility with CLARITY tissue clearing and light-sheet microscopy. LNP signals remained detectable in lung tissue 1 hour post-injection and in liver tissue at 24 and 72 hours post-injection. Notably, SPARKLE LNPs accumulated in blood vessel regions, consistent with expected liver sinusoidal localization. This validation represents a significant methodological breakthrough, as conventional fluorescent labeling approaches fail during tissue clearing due to lipid membrane removal. The SPARKLE tag's unique chemistry enables peptide retention through crosslinking during fixation, preserving fluorescent signals for accurate biodistribution tracking.
HFD Model Characterization and Fibrosis Assessment
The HFD model successfully induced liver fibrosis, as evidenced by significant weight gain (40-50g by week 15) and increased collagen deposition. Quantitative segmentation analysis revealed a statistically significant difference in collagen percentage between control (20.03%) and HFD livers (32.99%, p = 0.0241).
LNP Biodistribution Patterns
The most significant finding emerged from comparing LNP distribution between healthy and fatty liver environments. In HFD livers, LNPs were widely distributed along tissue borders and frequently co-localized with high collagen regions. Conversely, normal livers showed LNPs more localized in interior regions and perivascular spaces. This differential distribution pattern suggests that hepatic microenvironmental changes, particularly extracellular matrix remodeling, significantly impact LNP delivery efficacy. The preferential accumulation in fibrotic regions may indicate altered vascular permeability or modified cellular uptake mechanisms in diseased tissue, findings crucial for optimizing therapeutic targeting strategies.
Conclusion
This study successfully developed and validated innovative methodologies for tracking lipid nanoparticle biodistribution in both healthy and diseased liver environments. The research demonstrated that liver pathophysiology significantly influences LNP distribution patterns, with fibrotic tissues showing altered accumulation compared to healthy controls. The findings provide critical insights into designing more effective nanoparticle-based therapies for hepatocellular carcinoma treatment.
Notably, this research utilized the PreciGenome NanoGenerator Flex-S for LNP synthesis in the HFD study, demonstrating the platform's capability to produce consistent, well-characterized nanoparticles suitable for advanced in vivo applications.
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