From scaffold to structure: the synthetic production of cell derived extracellular matrix for liver tissue engineering

Abstract

Liver transplant is the only curative treatment option for patients with end-stage liver failure, however there are few donor livers available for transplant. Tissue engineering of a human liver would potentially solve the problem of escalating donor shortages. A major challenge presents itself in the form of the hepatic extracellular matrix (ECM); a finely controlled in vivo niche which supports hepatocytes and plays a critical role in the development of liver disease. Polymers and decellularized tissues each provide some of the necessary biological cues for the hepatocytes, however, neither alone has proved sufficient. Equally, the ability to fine tune the microenvironment using bioactive molecules presents researchers with the opportunity to create personalised niches for hepatocytes, representing both normal and diseased phenotypes. This study combines cell derived ECM with a fibronectin vector and electrospun scaffolding techniques to produce a platform for creating customisable ECM microenvironments for hepatocytes (Abstract image). The resulting poly-L-lactic acid-extracellular matrix (PLA-ECM) scaffolds were validated using HepG2 hepatocytes. As expected, statistically significant mechanical differences were observed between the synthetically derived ECM (SD-ECM) scaffolds and normal ECM (N-ECM) scaffolds, confirming that the ECM has been altered by the fibronectin producing vector. The PLA-ECM scaffolds maintained hepatocyte growth and function and influence the gene expression of key hepatic genes. Furthermore, immunohistochemistry showed SD and N-ECMs differed in ratios of Collagen I, Laminin and Fibronectin. Our results demonstrate that hybrid PLA-ECM scaffolds and the synthetic production of ECM provide a viable, translatable platform for customising microenvironments for hepatocytes. This technology offers a potential solution to current obstacles in regenerative medicine, disease modelling and whole organ tissue engineering.

Assessing the compatibility of primary human hepatocyte culture within porous silk sponges

“…Additionally, besides being mechanically weak, PEGDA requires modication with protease-activated peptides to render it biodegradable for integration with host tissue, which adds to fabrication complexity and cost, in addition to other immune response issues to the degrading PEGDA gel that has prompted others to develop alternative culture platforms to address some of these issues. 13,14 While both chitosan modied with galactosylated hyaluronic acid 15 and PLA 16 modied with extracellular matrix (ECM) proteins have been used for hepatocyte culture for 5-15 days in vitro, these studies have been restricted to either rat hepatocytes or cancerous hepatic cell lines, which do not fully represent PHH functions and oen require different culture conditions than their PHH counterparts. 6,7 Furthermore, chitosan scaffolds typically have low mechanical stability and a lack of porosity tunability, 17 while PLA induces a more severe inammatory reaction in animal models than collagen or silk lms.…”

Polymer- and Hybrid-Based Biomaterials for Interstitial, Connective, Vascular, Nerve, Visceral and Musculoskeletal Tissue Engineering

“…Adherence of NCI-H292 cells; tuning mechanical properties of materials [177,178,248] bFGF and AA2P based PGA/PLA Improving cells adhesion and stimulates cells proliferation and differentiation [249] Kidney (Section 6.2) Mg(OH) 2 and acellular ECM PLGA Neutralization of the effects induced by degradation of PLGA products, suppression of inflammatory reactions [186] l-DOPA and collagen IV PCL Improving cells adhesion and proliferation [250] Liver (Section 6.3) ECM-molecules PLA Microenvironment manipulation; changes of gene expression, protein contents, and cell adherence [251] PCL [252] HGF based Gelatin Controlled release for enhancement of the in vivo therapeutic effects RGD and YIGSR based PCL and PLA Improved hepatocyte adhesion [196] Cardiac muscles (Section 7.1) bFGF based PLGA Neovascular formation [253] Laminin based PU Improving cells adhesion [254] Skeletal muscles (Section 7.2)…”

A Hepatic Scaffold from Decellularized Liver Tissue: Food for Thought

“…The material must be biocompatible, biodegradable, non-toxic, and it must not generate adverse reactions once implanted in the body. Moreover, using these synthetic sources, no pathogenicity due to animal-derived materials would arise and good reproducibility is guaranteed in large-scale production [39]. Different biomaterials, such as polyethylene glycol (PEG), poly-l-lactic acid (PLLA), polycaprolactone (PCL), and thermoplastic polyurethane (PU), have been used for creating synthetic scaffolds in hepatic bioengineering [15,[40][41][42].…”