Search Results (176)

Liver failure and advanced chronic liver disease remain major causes of morbidity and mortality, while donor organ shortages, procedural complexity, cost, and the need for lifelong management after transplantation limit the availability of liver transplantation. Mesenchymal stromal cells (MSCs) have attracted substantial interest as a cell source for liver regeneration because of their accessibility, expansion capacity, immunomodulatory properties, and regenerative secretome. MSC-based hepatic differentiation, however, remains challenging, and cells generated in vitro frequently display an incomplete hepatocyte phenotype and limited maturation. Increasing evidence indicates that soluble differentiation factors alone are insufficient to reproduce the complex microenvironmental cues that regulate hepatic cell fate. Biomaterials can provide three-dimensional architecture, extracellular matrix (ECM) ligands, mechanical cues, cell-adhesive sites, and controlled presentation of growth factors, thereby acting as more than passive carriers of cells. In this mini-review, we summarize studies investigating natural and synthetic biomaterials for MSC hepatic differentiation, with emphasis on collagen-, gelatin-, heparin-, alginate-, and decellularized ECM-based systems as well as synthetic polymeric scaffolds such as poly(lactic-co-glycolic acid) and poly(L-lactic acid)-co-poly(ε-caprolactone). We discuss how biomaterial composition and three-dimensional organization may cooperate with hepatic differentiation media to promote hepatic phenotype and function. We also highlight an important distinction between expression of hepatic markers and acquisition of mature hepatocyte function, and identify opportunities for biomaterial systems that integrate biochemical, biophysical, and paracrine cues to achieve more reproducible hepatic maturation and clinically relevant liver regeneration. Full article

Cell sheet technology has evolved into a unique scaffold-free and biomaterial-free regenerative medicine platform that enables transplantation of intact cellular constructs while preserving extracellular matrix and cell–cell interactions. Clinical applications of cell sheet technology have demonstrated successful tissue and organ regeneration in the cornea, esophagus, heart, cartilage, and retina. More recently, the therapeutic scope of cell sheet technology has expanded beyond tissue replacement toward stem cell-based regenerative therapy, in which paracrine signaling, anti-fibrotic activity, and microenvironment remodeling play important roles. In this review, we use the term “functional regeneration” as an integrative therapeutic framework of a regenerative medicine platform capable of promoting the regenerative processes that modify disease pathophysiology and may alter the natural history of a disease, irrespective of complete anatomical reconstitution. Liver cirrhosis is a representative target disease for this concept of functional regeneration because the functional regenerative therapy that reverses progressive fibrosis and restores hepatic function has the opportunity to prevent the onset of hepatocellular carcinoma. This review discusses the evolution of cell sheet technology, the biological basis of stem cell-based functional regeneration, and the development of KCS-003, a cell sheet-based therapeutic product manufactured from mesenchymal stem/stromal cells preconditioned with IC-2, which has potent anti-fibrotic action and promotes liver regeneration. In addition, clinical investigations, including corneal and retinal reconstitution, esophageal regeneration, cartilage repair, and cardiac patches, were shown as representative clinical cases of cell sheet technology. Full article

The liver is an immunologically distinctive organ. Portal blood continuously delivers gut-derived antigens and microbial products, requiring hepatic immunity to balance surveillance with restraint. In hepatocellular carcinoma (HCC), this physiology is commonly overlaid by chronic injury, inflammation, and fibrosis, so the background liver forms part of the disease context in which the tumor microenvironment (TME) develops. This review synthesizes how cellular architecture, tumor-intrinsic programs, and structural, metabolic, and microbial conditions interact to shape immune evasion and heterogeneity. HCC provides the principal evidence base, with intrahepatic cholangiocarcinoma (iCCA) used as a structured, biologically distinct comparator. We organize therapies by the microenvironmental barriers they are intended to modify and distinguish established clinical efficacy from evidence that the proposed mechanisms mediate treatment benefit. Single-cell and spatial studies have resolved cellular states and spatial arrangements, including onco-fetal endothelial–myeloid neighborhoods and a macrophage–fibroblast boundary band separating lymphocyte-rich stroma from malignant tissue. These patterns operate within fibrotic and metabolically altered tissue and vary by etiology, spatial context, and tumor type. Vascular endothelial growth factor blockade with immune checkpoint inhibition and dual checkpoint blockade are established first-line options in advanced HCC. Chemo-immunotherapy is established in biliary tract cancer, and IDH1 inhibition has established efficacy in IDH1-mutant cholangiocarcinoma. Myeloid- and stroma-directed strategies, natural-product approaches, and engineered-cell therapies remain preclinical or early clinical. None of the pivotal trials tested whether the proposed microenvironmental mechanism mediated treatment benefit. The liver TME informs treatment selection without yet determining it. Full article

Metabolic dysfunction-associated steatotic liver disease (MASLD) and its progressive form, metabolic dysfunction-associated steatohepatitis (MASH), are a growing global health burden with extremely limited pharmacological options, thereby indicating an urgent need for innovative therapeutic strategies. Hepatokines are liver-derived secreted proteins that coordinate metabolic communication between the liver and peripheral organs and have emerged as mechanistically compelling therapeutic candidates. This review comprehensively examines beneficial hepatokines with protective roles in MASLD/MASH, detailing their molecular mechanisms of action across key metabolic tissues, including their effects on hepatic lipid metabolism, insulin sensitivity, inflammatory signaling, and fibrogenesis. We further discuss the fundamental pharmacokinetic barriers of these protein therapeutics, particularly their susceptibility to renal clearance and proteolytic degradation. Furthermore, we examine the principal half-life extension strategies to overcome these limitations, with particular emphasis on their clinical application to FGF21-based drug candidates that are currently advancing through phase 3 trials. Overall, this review highlights the therapeutic potential of hepatokine-based biologics and the critical role of protein engineering in translating these mechanistic insights into durable, clinically viable treatments for MASLD/MASH. Full article

Drug-induced liver injury (DILI) remains a major cause of acute liver failure and drug withdrawal from the market. Recently developed three-dimensional (3D) hepatic in vitro systems exhibit improved functionality and drug sensitivity compared with conventional two-dimensional cultures. These 3D models range from simple physiologic-like culture systems to advanced bioreactors with dynamic flow to provide sufficient nutrients and consistent drug exposure. However, whether dynamic perfusion improves sensitivity and reproducibility of hepatotoxicity testing remains unclear. Here, we developed a tailor-made perfusion platform to support volumetric bioprinted hepatic constructs for hepatotoxicity testing. The constructs consist of intrahepatic cholangiocyte organoids (ICOs) differentiated towards hepatocyte lineage and embedded in a gelatin methacryloyl bioresin. For toxicity evaluation, the hepatocyte-like ICO constructs were exposed to prolonged subtoxic acetaminophen treatment (10 mM, 7 days). The perfusion system effectively maintained and enhanced hepatocyte differentiation, evidenced by upregulated hepatic markers under perfused conditions compared to static controls. Testing of acetaminophen hepatotoxicity revealed that the perfused constructs displayed elevated cellular injury, with markedly higher liver injury markers relative to controls. Collectively, this study demonstrates the successful application of perfusion-based 3D model culture and highlights its potential as a more physiological platform for hepatotoxicity risk assessment in drug discovery and regenerative medicine. Full article

Background/Objectives: Pulmonary fibrosis is a progressive and fatal disease characterized by excessive extracellular matrix deposition and irreversible lung remodeling. Although modified mRNA (modRNA) therapeutics offer a promising strategy for regulating disease-driving pathways, effective pulmonary delivery remains challenging due to the inherent liver tropism of conventional lipid nanoparticles (LNPs). This study aimed to establish an optimized platform for lung-selective modRNA delivery and therapeutic screening for pulmonary fibrosis. Methods: A panel of charge-modified LNP formulations was evaluated in vivo for pulmonary tropism following systemic administration of luciferase (Luc) modRNA. Administration routes, biodistribution in healthy and bleomycin (BLM)-induced fibrotic lungs, and endogenous microRNA (miRNA)-mediated de-targeting strategies were assessed. Candidate antifibrotic modRNAs targeting the transforming growth factor-beta (TGF-β) signaling pathway were subsequently evaluated in normal human lung fibroblasts (NHLFs). Results: Among the formulations tested, 50% DOTAP MC3 LNPs demonstrated the most favorable balance of pulmonary transfection, physicochemical properties, and limited off-target expression. Intravenous (IV) administration achieved robust lung expression with a superior safety profile compared with intratracheal (IT) delivery. Importantly, pulmonary biodistribution was preserved in BLM-induced fibrotic lungs despite extensive tissue remodeling. Incorporation of miR-122 recognition sites further enhanced selectivity, resulting in 94.5% of total transgene expression being localized to the lungs while substantially reducing residual hepatic expression. In vitro screening identified dominant-negative TGF-β receptor II (DNTGFBR2) modRNA as a potent inhibitor of TGF-β-induced fibrotic activation, significantly suppressing α-SMA and CTGF expression. Conclusions: These findings establish a comprehensive platform for pulmonary modRNA therapeutic development by integrating lung-selective LNP engineering, optimal systemic delivery, miRNA-mediated de-targeting, and therapeutic payload screening. This strategy provides a foundation for the development of targeted RNA therapies for pulmonary fibrosis and other organ-specific diseases. Full article

Ex vivo liver perfusion (EVLP) sustains human or large animal livers outside the body under near-physiological conditions, enabling functional monitoring for lactate clearance, bile production, and oxygen consumption and allowing targeted therapeutic interventions. Originally developed to optimize donor grafts for transplantation, EVLP has evolved into a powerful translational research platform bridging preclinical discovery and early clinical translation. This review discusses EVLP as a platform for gene therapy, immunotherapy, pharmacology, and personalized medicine, with particular emphasis on gene- and immune-based interventions as mechanistically mature exemplars. We consolidate advances in pharmacological testing and toxicity modeling, viral and non-viral gene delivery, genome engineering, and immunomodulation using perfused livers. We further describe emerging applications, including autologous EVLP pathways for organ-confined therapy, ex vivo liver surgery, and bioengineering strategies such as biliary organoid repair, RNA interference, and mitochondrial transfer. We highlight how these applications align with a paradigm shift in biomedical research, including the NIH’s recent initiative to prioritize human-based experimental models over animal-only studies. By leveraging transplant-declined or surgically resected organs that would otherwise be unused, ex vivo perfusion bridges the gap between pre-clinical testing and clinical practice, enabling real-time evaluation of interventions in functional human tissue. We discuss both the scientific opportunities afforded by EVLP and the technical, biosafety, and ethical challenges that must be addressed to enable responsible clinical translation. Full article

This study presents a comprehensive computational evaluation of radiofrequency (RF) ablation efficacy and the spatial formation of thermal ablation zones within a 3D model of a liver tumor. By systematically comparing these configurations, the study aims to elucidate the physical mechanisms governing electromagnetic (EM) energy dissipation in hepatic tissue and to provide clear engineering guidelines for optimizing RF applicator selection and treatment planning in clinical practice. To reliably simulate the biophysical phenomena of the RF ablation procedure, a coupled electro-thermal model based on the finite element method and the Pennes bioheat equation was implemented. The research investigates six distinct applicator variants: conventional needle-type applicators and advanced expandable umbrella-type RF applicators equipped with four- and eight-tine electrodes, each evaluated in both monopolar and bipolar configurations. Numerical simulations were conducted for a standard 10 min ablation procedure at varying applied voltages to assess the specific absorption rate (SAR) distribution, transient heating dynamics, and the exact volumes of the resulting coagulation necrosis which were quantified using rigorous isotherms and the cumulative equivalent minutes at 43 °C (CEM₄₃) thermal dose index. Volumetric analysis of the ablation zones revealed that bipolar multi-tine electrodes induce highly localized heat concentration. Conversely, monopolar multi-tine setups strongly disperse EM energy. The results demonstrated that, for conventional needle applicators, the monopolar configuration generated significantly larger necrosis zones than the bipolar operating mode. The RF applicator geometry and its operating mode directly dictate the spatial extent of liver tissue necrosis. Moreover, advanced numerical treatment planning is essential for optimizing SAR and CEM₄₃ distributions and ensuring safe and complete hepatocellular carcinoma eradication. Full article

Annually, there are more than two million deaths from liver disease. This is driven by organ inflammation and scarring, leading to a decline in function and regeneration. Frequently, this can develop into decompensated liver disease, resulting in the loss of physiological balance and toxin build-up within the body, with an increased risk of patient mortality. Currently, there are no approved medicines for the long-term treatment of liver cirrhosis. The only successful treatment option for end-stage liver disease patients is donor organ transplantation. However, patient requirement outstrips the number of donated organs. To address this bottleneck, researchers around the world have developed cell-based prototype systems to restore failing liver function, with some in clinical trials. Although significant progress has been made, no mainstream commercial liver assist products are available for routine clinical use. In this study we developed a stem cell-derived vascularized liver tissue implant prototype from pluripotent cells. The liver tissue was produced from a stem cell line that is banked at clinical grade, and displayed stable and mature liver function over a 6-week period in vitro. This included decreasing levels of the fetal marker, alpha-fetoprotein, when the serum albumin increased. This was further supported by stable alpha-1-antitrypsin secretion and cytochrome P450 function. Following the establishment of stable liver tissue, it was delivered as a cell product or attached to an electrospun polycaprolactone scaffold, to form a tissue implant. Next, cellular material was quality-controlled, and subsequently shipped to a contract research organization for external in vivo validation. The transplanted liver tissue functioned when implanted into the kidney capsule and subcutaneously, remaining functional for up to two weeks in vivo. Full article

Primary biliary cholangitis (PBC) is an autoimmune-mediated cholestatic liver disease characterized by the progressive destruction of intrahepatic bile ducts, which ultimately leads to hepatic fibrosis and cirrhosis. The current first-line therapy, ursodeoxycholic acid, is associated with a high rate of non-response. Moreover, second-line treatments are constrained by variable efficacy and safety concerns. Mesenchymal stem cells (MSCs), owing to their potent immunomodulatory and tissue-repairing capabilities, represent a promising new therapeutic strategy for PBC patients with poor response to conventional therapies. This review systematically outlines the pathogenesis of PBC, focusing on factors including genetics, environment, and immune dysregulation. Furthermore, it examines recent evidence on the mechanisms by which MSCs and their derivatives, such as exosomes, may intervene in PBC progression through immunomodulation, anti-fibrotic effects, and potential hepatic differentiation. This paper also reviews the current status and challenges of the clinical translation of MSCs therapy, and proposes that engineered modification and standardized preparation are the key directions to promote its application. In conclusion, this review provides a theoretical foundation and future directions for deepening the understanding of PBC pathogenesis and developing novel MSC-based therapeutic strategies. Full article

Chronic liver disease remains a major global health burden, with liver transplantation as the only definitive therapy despite severe limitations in donor availability, surgical morbidity, and patient eligibility. Although the liver has substantial intrinsic regenerative capacity, endogenous repair is often insufficient in chronic injury, cirrhosis, and acute-on-chronic liver failure. As a result, regenerative strategies that restore liver function without whole-organ replacement are increasingly pursued. This review examines controlled release biomaterial-based liver regeneration platforms, particularly those that utilize hydrogels and/or complementary nanoparticle systems, as clinically practical tools to enhance endogenous regeneration. We include discussion of both 3D scaffold-based and injectable hydrogels to enhance regeneration. Used as biological support and controlled release mixtures, they enable local retention, entrapping and controlling the release of regenerative cues including growth factors (HGF, EGF, etc.), nucleic acids for gene expression, stem cells or other cell populations, and conditioned extracellular vesicles, overcoming poor cell engraftment, short cytokine half-lives, and other limitations. Further, synthetic nanoparticles can structure release at the protein/molecular level as well as catalytically modulating oxidative stress and inflammation. Within the context of these systems, we structure the anatomical, engineering, and imaging considerations essential for the clinical translation of gel composite systems while highlighting remaining barriers to wider clinical adoption. Collectively, these advances position biomaterial-enabled regenerative therapies as a realistic alternative or bridge to donor restricted liver transplantation. Full article

Lipid nanoparticles (LNPs) have become an important platform for the delivery of RNA therapeutics, including messenger RNA (mRNA) and small interfering RNA (siRNA). However, most clinically approved LNP formulations exhibit strong liver tropism following systemic administration, which limits efficient delivery to extrahepatic tissues. This inherent biodistribution profile has therefore been recognized as a key challenge for expanding the therapeutic applications of RNA nanomedicine. Recent efforts have focused on engineering functionalized LNP systems to improve delivery specificity beyond the liver. Surface modification with targeting ligands—such as antibodies, peptides, and nucleic acid aptamers—can promote receptor-mediated uptake by specific immune cell populations, including macrophages, dendritic cells and T lymphocytes. In parallel, advances in lipid design have improved intracellular RNA delivery by facilitating endosomal escape. These developments have broadened the potential use of RNA nanomedicine for inflammatory disorders, including autoimmune diseases, neuroinflammation, and cardiovascular inflammation. Functionalized LNPs are also being investigated for in vivo engineering of immune cells. This review summarizes current strategies for designing functionalized LNP systems, highlights their emerging applications in immune and inflammatory diseases, and discusses key challenges for clinical translation. Full article

Tissue engineering integrates concepts from medicine, biology, and engineering to create living constructs capable of repairing, replacing, or supporting damaged tissues. This multidisciplinary field relies on the interplay between biomaterials, cellular sources, and bioactive signaling to achieve functional tissue regeneration. This review provides a comprehensive overview of recent advances in scaffold design, highlighting natural, synthetic, and hybrid materials, as well as innovative fabrication techniques such as electrospinning, 3D bioprinting, and smart biomaterials. It discusses the role of stem cells and growth factors in directing regeneration and examines a wide range of clinical applications, including skin regeneration, cartilage repair, bone tissue engineering, dental and periodontal regeneration, nerve repair, cardiac tissue engineering, liver tissue models, and ophthalmic applications. Current challenges, such as immune responses, limited vascularization, scalability, and regulatory barriers, are addressed alongside emerging strategies aimed at improving clinical translation. By integrating diverse tissue types and engineering approaches within a unified framework, this review offers a broad yet detailed perspective on the current state and future directions of regenerative medicine. Full article

Aging is a complex biological process characterized by progressive loss of cellular homeostasis, impaired regenerative capacity, and accumulation of senescent cells that collectively predispose tissues to disease. Traditional two-dimensional culture systems and animal models have provided valuable insights but fail to fully recapitulate the spatial organization, cellular heterogeneity, and microenvironmental cues of aging human tissues. Organoid technology—three-dimensional self-organizing structures derived from adult stem cells or pluripotent stem cells has emerged as a transformative platform to model aging in vitro. These mini-tissues retain the architecture, signaling dynamics, and lineage hierarchy of native organs, making them powerful systems to interrogate age-associated cellular phenotypes, DNA damage responses, and senescence programs. This review discusses how organoid models are advancing our understanding of aging biology across multiple organ systems, from the intestines and liver to the brain and lung. We highlighted key molecular pathways driving cellular senescence within organoids—including p16INK4a/p21CIP1 signaling, SASP activation, mitochondrial dysfunction, and epigenetic drift—and how these can be targeted to restore tissue homeostasis. We further discussed how organoids derived from aged tissues, induced pluripotent stem cells, and engineered oncogene systems reveal new therapeutic opportunities to modulate senescence in age-related disorders, cancer, and regenerative medicine. Finally, we discussed emerging integrative tools such as organoid co-cultures, single-cell omics, and senolytics drug screening that are expanding the potential of organoids as translational platforms for anti-aging and disease intervention. Full article

Ubiquitin-specific protease 2 (USP2) is a deubiquitinase that controls various cellular events, including cell cycle progression and tumorigenesis. Along with cell culture models, mouse models induced using chemical blockers and gene engineering have substantially contributed to our knowledge of the crucial roles of USP2 in energy metabolism and metabolic disorders. This review summarizes the evidence of the role of USP2 in regulating energy metabolism in mice and cells under physiological and pathological conditions. In hepatocytes, a short isoform of USP2, USP2b, aggravates type 2 diabetes and metabolic dysfunction-associated steatotic liver disease. Meanwhile, a long isoform of USP2 in adipose tissue macrophages, USP2a, attenuates the onset of diabetes. USP2a mitigates insulin resistance and subsequent muscle atrophy. In ventromedial hypothalamic neurons, USP2b inhibits an increase in blood glucose by repressing hepatic glycogenolysis. In addition to regulating diabetes, USP2 isoforms potentially regulate the progression of atherosclerosis by modulating macrophages and hepatocytes. In brown adipose tissue, USP2a regulates thermogenesis, thus influencing systemic energy control. Meanwhile, in testicular macrophages, USP2 protects the mitochondrial respiration of sperm and consequently contributes to maintaining the quality of frozen sperm for use in the treatment of male infertility. As USP2 is distributed to multiple cellular components, it mediates the polyubiquitination of various molecules. For instance, USP2 modulates the stability of various transcription regulators, including C/EBP-α, PPARγ, EBF2, and PGC1α. The accumulating evidence indicates that USP2 functions as a modulatory molecule for energy metabolism across organs. Full article