The Liver

The liver is a complex soft organ composed of parenchymal cells, such as hepatocytes, hepatocyte precursor cells (oval cells or Ito cells), stellate cells, Kupffer cells, epithelial cells, sinusoidal epithelial cells, biliary epithelial cells, and fibroblasts [67]. Liver cells are mitotically quiescent, although they are all capable of undergoing division, for example after partial resection of the liver. Hepatocytes are instrumental in detoxification and drug metabolism, involving a large group of enzymes coupled to different families of cytochrome P-450 proteins. Other crucial functions of the liver include the production/synthesis of albumin, blood clotting factors and a/P globulins [10]. In spite of the fact that a (healthy) liver has a large capacity for regeneration, and that liver transplants have become more feasible (i.e., through live donors), there is a continual need for engineered liver tissue for implantation in those patients with hepatic failure. Engineered liver tissue may be also useful for the design of in-vitro pharmacological models that could assist in the discovery and characterization of novel compounds, which target liver diseases or for predicting the liver metabolism of newly developed drugs.

Hepatocytes, the basic cellular units of the liver, represent 60% of all the cells in the liver; therefore, most attempts at engineering liver tissue focus primarily on their use. A first critical step in liver tissue engineering is the development of an appropriate scaffold (matrix) on which cultured hepatocytes can attain and retain the full repertoire of their biological functions. To achieve these goals, different 3D scaffolds were developed which mimicked the liver environment and allowed suitable growth and function of hepatocytes.

12 | 1 Intelligent Biomatrices and Engineered Tissue Constructs 1.4.2

0 0

Post a comment