Littérature scientifique sur le sujet « Hydroscaffold »

The 3Rs guidelines recommend replacing animal testing with alternative models. One of the solutions proposed is organ-on-chip technology in which liver-on-chip is one of the most promising alternatives for drug screening and toxicological assays. The main challenge is to achieve the relevant in vivo-like functionalities of the liver tissue in an optimized cellular microenvironment. Here, we investigated the development of hepatic cells under dynamic conditions inside a 3D hydroscaffold embedded in a microfluidic device. The hydroscaffold is made of hyaluronic acid and composed of liver extracellular matrix components (galactosamine, collagen I/IV) with RGDS (Arg-Gly-Asp-Ser) sites for cell adhesion. The HepG2/C3A cell line was cultured under a flow rate of 10 µL/min for 21 days. After seeding, the cells formed aggregates and proliferated, forming 3D spheroids. The cell viability, functionality, and spheroid integrity were investigated and compared to static cultures. The results showed a 3D aggregate organization of the cells up to large spheroid formations, high viability and albumin production, and an enhancement of HepG2 cell functionalities. Overall, these results highlighted the role of the liver-on-chip model coupled with a hydroscaffold in the enhancement of cell functions and its potential for engineering a relevant liver model for drug screening and disease study.

AbstractThe liver plays a key role in the metabolism of lipoproteins, controlling both production and catabolism. To accelerate the development of new lipid‐lowering therapies in humans, it is essential to have a relevant in vitro study model available. The current hepatocyte‐like cells (HLCs) models derived from hiPSC can be used to model many genetically driven diseases but require further improvement to better recapitulate the complexity of liver functions. Here, we aimed to improve the maturation of HLCs using a three‐dimensional (3D) approach using Biomimesys®, a hyaluronic acid‐based hydroscaffold in which hiPSCs may directly form aggregates and differentiate toward a functional liver organoid model. After a 28‐day differentiation 3D protocol, we showed that many hepatic genes were upregulated in the 3D model (liver organoids) in comparison with the 2D model (HLCs). Liver organoids, grown on Biomimesys®, exhibited an autonomous cell organization, were composed of different cell types and displayed enhanced cytochromes P450 activities compared to HLCs. Regarding the functional capacities of these organoids, we showed that they were able to accumulate lipids (hepatic steatosis), internalize low‐density lipoprotein and secrete apolipoprotein B. Interestingly, we showed for the first time that this model was also able to produce apolipoprotein (a), the apolipoprotein (a) specific of Lp(a). This innovative hiPSC‐derived liver organoid model may serve as a relevant model for studying human lipopoprotein metabolism, including Lp(a).

Au cours des programmes de développement de médicaments, des modèles animaux sont utilisés pour évaluer le métabolisme et la toxicité des médicaments. Plusieurs cadres juridiques sont établis pour le remplacement, la réduction et l'amélioration de ces expériences. Le foie est un organe central pour la détoxification des molécules exogènes. Par conséquent, le développement de modèles reproduisant les fonctions du foie reste un objectif ambitieux. Ces dernières années, l'association entre l'ingénierie tissulaire et la technologie des organes sur puce a conduit au développement de modèles alternatifs imitant certaines fonctions hépatiques. L'objectif de ce travail est de développer une plateforme de foie sur puce biomimétique en couplant une biopuce d'hépatocytes et une barrière endothéliale. Dans la première partie, nous avons utilisé la technologie des organes sur puce et un hydroscaffold à base de matrice extracellulaire pour organiser les cellules en 3D. Les sphéroïdes formés ont été caractérisés sur le plan structurel et fonctionnel. Dans la deuxième partie, nous avons caractérisé la formation d'une barrière endothéliale. Nous avons établi les conditions de co-culture et analysé le potentiel du couplage de la barrière endothéliale avec la puce d'hépatocytes pour métaboliser l'APAP. Enfin, nous avons analysé la signature métabolomique de chaque condition, les interactions entre les cellules et identifié la signature métabolique des lésions causées par l'APAP. Dans la dernière partie, nous avons proposé des pistes d'amélioration en utilisant des hépatocytes primaires ou en intégrant la barrière endothéliale et les hépatocytes dans une biopuce bi-comportementalisée
During drugs development programs, animal models are commonly used for the assessment of the metabolism and toxicity of drug candidates. Several legal frameworks are being settled to promote the replacement, the reduction, and the refinement of these experiments. The liver is a central organ involved in the detoxification of exogenous molecules. Accordingly, the development of models mimicking the functions of the liver remain a challenging objective. Conventionally, liver cells are cultured in vitro in 2D Petri dishes but this conformation leads to a rapid loss of their functions. In recent years, the association between tissue engineering and organ-on-chip technology led to the development of more accurate alternative models that mimic the liver functions. The aim of this thesis is to develop a biomimetic liver-on-chip platform by coupling a hepatocyte biochip and an endothelial-like barrier. The goal is to mimic the passage of molecules through the liver sinusoid endothelial barrier and then their metabolism with the hepatocytes. In the first part, we used organ-on-chip technology and ECM-based hydroscaffold to organise the cells in 3D structures. The potential of our model was compared with static Petri dishes and the spheroids formed were characterised structurally and functionally. In the second part, we characterized the formation of an endothelial barrier and identified specific markers indicating the conservation of the phenotype of endothelial cells. We established the coculture conditions and analysed the potential of coupling the endothelial barrier with the hepatocyte-on-chip to metabolize the APAP as a candidate molecule. Finally, we analysed the metabolomic signature of each condition, crosstalk between the cells, and identified the metabolic signature of APAP injury and described the reactions happening at metabolic level. In the last part, we proposed tracks of improvement by using primary hepatocytes or by integrating the endothelial barrier and the hepatocytes in the same bi-compartmentalized biochip