Nanoparticle-based systems for liver therapy: Overcoming fibrosis and enhancing drug efficacy.

Liver diseases are among the most insidious and life-threatening conditions due to their progressive nature and late symptom onset. Cirrhosis and hepatocellular carcinoma account for most liver-related deaths, often following the progression from fibrosis. Fibrosis creates a hostile microenvironment, characterized by portal hypertension, vascular capillarization, intrahepatic vasoconstriction, and extracellular matrix deposition, which severely limits drug efficacy. Advances in pharmaceutical science have prompted efforts to develop liver-targeted drug delivery systems to prevent or reduce the progression of fibrosis, a central feature of many liver diseases. Fibrosis often reduces the in vivo efficacy of both approved and experimental drugs, underscoring the need for improved delivery strategies focused on stability, controlled release, and precise targeting. Nanoparticle (NP)-based systems show promise, either by delivering therapeutic agents, or in some cases, by contributing directly to the therapeutic effects. This review summarizes the main types of NPs explored for liver disease treatment, especially those aiming to reverse fibrosis or prevent its progression, a critical therapeutic target in chronic liver diseases. Additionally, it examines gene delivery and ultrasound-guided microbubble strategies, which can be combined with NPs to improve cell-specific targeting and boost therapeutic effects. Together, these approaches have the potential to address current therapeutic challenges and accelerate the development of liver-targeted treatments for clinical application.