Preclinical characterization of alginate‐poly‐L‐lysine encapsulated HepaRG for extracorporeal liver supply

Abstract

We recently demonstrated that HepaRG cells encapsulated into 1.5% alginate beads are capable of self-assembling into spheroids. They adequately differentiate into hepatocyte-like cells, with hepatic features observed at Day 14 post-encapsulation required for external bioartificial liver applications. Preliminary investigations performed within a bioreactor under shear stress conditions and using a culture medium mimicking acute liver failure (ALF) highlighted the need to reinforce beads with a polymer coating. We demonstrated in a first step that a poly-L-lysine coating improved the mechanical stability, without altering the metabolic activities necessary for bioartificial liver applications (such as ammonia and lactate elimination). In a second step, we tested the optimized biomass in a newly designed perfused dynamic bioreactor, in the presence of the medium model for pathological plasma for 6 h. Performances of the biomass were enhanced as compared to the steady configuration, demonstrating its efficacy in decreasing the typical toxins of ALF. This type of bioreactor is easy to scale up as it relies on the number of micro-encapsulated cells, and could provide an adequate hepatic biomass for liver supply. Its design allows it to be integrated into a hybrid artificial/bioartificial liver setup for further clinical studies regarding its impact on ALF animal models.

Microencapsulated Hepatocytes Differentiated from Human Induced Pluripotent Stem Cells: Optimizing 3D Culture for Tissue Engineering Applications

“…The ability of cells to detoxify lactate and ammonia at levels higher than physiological norms was assessed after incubating the cells in culture medium supplemented with NH 4 Cl (Sigma-Aldrich) and L-Lactate (Sigma-Aldrich). Two conditions were assessed: (1) the samples were incubated for 2 h with medium containing 1.5 mM NH 4 Cl and 2 mM L-Lactate, as described previously [ 21 ], and (2) the samples were incubated for 6 h in ultra-pathological model plasma containing 70 g/L bovine serum albumin (BSA, Sigma-Aldrich), 2 mM NH 4 Cl and 7 mM L-Lactate [ 30 ]. After incubation, the supernatant was collected and frozen at −20 °C until analysis.…”

Pancreatic islet transplantation: current advances and challenges

“…One strategy is encapsulating islet cells without immunosuppression to solve the immune rejection problem in porcine islet xenotransplantation. Various natural or synthetic biomaterials are used for encapsulation, such as polyethylene glycol diacrylate (PEG-DA) ( 65 ), agarose ( 66 ), and other biological materials like alginate ( 67 ). Coating islet cells with alginate films containing polyethylene glycol acrylate has allowed survival up to 6 months without immunosuppression ( 68 , 69 ).…”

Multiparametric Material Functionality of Microtissue‐Based In Vitro Models as Alternatives to Animal Testing

“…Herein, PLL reinforced the mechanical stability of pure alginate microbeads, whereby the elastic module increased from ≈1 to 5 kPa with PLL modification. [ 166 ]…”

“…Herein, PLL reinforced the mechanical stability of pure alginate microbeads, whereby the elastic module increased from ≈1 to 5 kPa with PLL modification. [166] Due to its LCST slightly above the physiological temperature range (LCST = 40-50 °C), methyl cellulose is usually viscous at physiological conditions and has a correspondingly low mechanical strength. [107] An increase in viscosity could be improved by increasing the polymer concentration and the molar mass of the polymer strands.…”